EPA/530-SW-91-065D
PB92-124791
Mining Sites on the National Priorities List
NPL Site Summary Reports
U.S. Environmental Protection Agency
Office of Solid Waste
June 21, 1991
FINAL DRAFT
Volume IV
Prepared by :
Science Applications International Corporation
Environmental and Health Sciences Group
7600-A Leesburg Pike
Falls Church, Virginia 22043
REPRODUCED BY
U.S. DEPARTMENT OF COMMERCE
NATIONAL TECHNICAL
INFORMATION SERVICE
SPRINGFIELD. VA 22161
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50272-101
REPORT DOCUMENTATION
3.
PA6E
4.
7.
9.
EPA/530-SW-91-065D
Title and Subtitle
MINING SITES ON THE NATIONAL PIRORITIES LIST: NPL SITE SUMMARY REPORTS
(FINAL DRAFT) VOLUME IV: ORONOSO-DUENWEG MINIMS BELT TO TAR CREEK]
Author (s)
V. HOUSEMAN/OSH
Performing Organization Nate and Address
PB92-124791
5. Report Date
JUNE 21. 1991
6.
8. Performing Organization Rept. No
10. Project/Task/Work Unit No.
U.S. EPA
Office of Solid Waste
401 M. Street SW
Mashington, DC 204AO
11. Contract(C) or Grant(B) No.
(C)
(6)
12. Sponsoring Organization Name and Address
SAIC
ENVIRONMENTAL & HEALTH SCIENCES GROUP
7600-A LEESBUR6 PIKE
FALLS CHURCH. VA 22045
13. Type of Report & Period Covered
SUMMARY REPORT
__
15. Suppleaentary Notes
16. Abstract (Limit: 200 words)
Volume IV of the Mining Sites on the National Priorities List contains the following NPL Site Summary Reports: Oronogo-
Deunweg Mining Belt, Palmerton Zinc, Sharon Steel/Midvale Tailings, Silver Bow Creek/Butte Area Site, Silver Mountain
Mine, Smuggler MOuntain, St. Louis Airport/Hazelwood Interim/Futura Coatings, Sulphur Bank Mercury Mine, and Tar Creek.
17. Document Analysis a. Descriptors
b. Identifiers/Open-Ended Terms
c. COSATI Field/Group
18. Availability Statement
RELEASE UNLIMITED
(See ANSI-Z39.18)
/
19. Security Class (This Report)
UNCLASSIFIED
20. Security Class (This Page)
UNCLASSIFIED
OPT]
(For
21. No. of Pages
22. Price
0
ONAL FORM 272 (4-77)
•merly NTIS-35)
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Oronogo-Duenweg Mining Belt Mining Waste NPL Site Summary Report
Reference 1
Excerpts From Preliminary Health Assessment for Oronogo-Duenweg Mining Belt,
Jasper County, Missouri, CERCLIS No. MDD980686281;
Department of Health and Human Services and ATSDR; June 18, 1990
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E? T B’r:S IC LJ STE REGS DEPT 2— 3—92 i.2:2SPtl
703821 477S
32 . aigs; 3
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON. D.C. 20480
OFFUCE OF
SOL.IO WASTE AND EMERGENCY RESPON3E
D
Appendices of these reports include excerpted
pages from documents referenced in the text of
the reports, and as a result, page numbers in
the appendices axe not necessarily consecutive.
In addition, since many of the references are
3rd or 4th generation copies, some pages may
not be legible, but are the best available.
; i
i nntac’ on Reernd P9 r
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Mining Waste NPL Site Summary Report
Oronogo-Duenweg Mining Belt
Jasper County, Missouri
U.S. Environmental Protection Agency
Office of Solid Waste
June 21, 1991
FINAL DRAFT
Prepared by:
Science Applications International Corporation
Environmental and Health Sciences Group
7600-A Leesburg Pike
Falls Church, Virginia 22043
I, I
I, 1
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Mining Sites on the National Priorities List
- - NPL Site Summary Reports
TABLE OF CONTENTS
Volume IV
Oronogo-Duenweg Mining Belt
Palmerton Zinc
Sharon Steel/Midvale Tailings
Silver Bow Creek/Butte Area Site
Silver Mountain Mine
Smuggler Mountain
St. Louis Airport/Hazeiwood Interim/Futura Coatings
Sulphur Bank Mercury Mine
Tar Creek
Jasper Co., MO
Palmerton, PA
Midvale, UT
Butte, MT
Loomis, WA
Pitkin Co., CO
St. Louis Co., MO
Lake Co., CA
Ottawa Co., OK/Cherokee Co., KS
iv
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V
DISCLAIMER AND ACKNOWLEDGEMENTS
The mention of company or product names is not to be considered an
endorsement by the U.S. Environmental Protection Agency (EPA).
This document was prepared by Science Applications International
Corporation (SAIC) in partial fulfillment of EPA Contract Number
68-W0-0025, Work Assignment Number 20. A previous draft of this
report was reviewed by Mark A. Bogina of EPA Region VII [ (313)
551-7528], the Remedial Project Manager for the site, whose
comments have been incorporated into the report.
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Mining Waste NPL Site Summary Report
ORONOGO-DUENWEG MINING BELT
JASPER COUNTY, MISSOURI
INTRODUCTION
This Site Summary Report for the Oronogo-Duenweg Mining Belt site is one of a series of reports on
mining sites on the National Priorities List (NPL). The reports have been prepared to support EPA’s
mining program activities. In general, these reports summarize types of environmental damages and
associated mining waste management practices at sites on (or proposed for) the NPL as of February
11, 1991 (56 Federal Register 5598). This summary report is based on information obtained from
EPA files and reports and on a review of the summary by the Remedial Project Manager for the site,
Mark Bogina.
SITE OVERVIEW
The Oronogo-Duenweg Mining Belt Site, located near the City of Joplin in Jasper County, Missouri,
is one of two sites located in the Missouri portion of the Tn-State (Missouri, Kansas, and Oklahoma)
Mining District (see Figure 1). The 20-square mile Oronogo-Duenweg Mining Belt site was the
location of the most concentrated mining activities in the 2,400-square mile Tn-State Mining District
(Reference 1, page 1; Reference 2, page 2-1; Reference 3, page 3).
Horizontal mine shafts, open pits, open vertical shafts, and tailings piles remain from commercial lead
and zinc mining operations that were in production from the 1850’s through the late 1960’s. The
Oronogo-Duenweg Mining Belt Site is located within two drainage areas — the Center Creek drainage
area located northeast of Joplin, and the Turkey Creek drainage area located immediately north of
Joplin. Approximately 4.6 square miles of tailings exist in the Joplin area, two thirds of which are in
the Center Creek drainage area (Reference 1, page 1-2). EPA estimated that 20 to 100 million tons
of mining waste are present at the site, and that the area affected by the site may be as much as 30
square miles.
The primary contaminants of concern at the site are cadmium, lead, and zinc. All three of these
contaminants have been detected at elevated concentrations in ground water, surface water, and
sediments. Nickel and mercury have also been detected in environmental media at the site, but their
concentrations are presently not considered to be a public health concern. Surface waters from Center
and Shoal Creeks (as well as pit water) may be used for crop irrigation, livestock watering, sport
fishing, and commercial and recreational purposes (Reference 1, pages 3 and 4).
1
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Orono o-Duenweg Mixiing Belt
FIGURE 1. LOCATION MAP MISSOURI STUDY AREA, TRI’STATE DISTRICT
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Mining Waste NPL Site Summary Report
However, surface water contained in most abandoned pits is too acidic to support aquatic blots, and is
not suitable for that sport fishing, as fish cannot survive in such environments. In addition, most
surface waters contained in the mined pits are too corrosive to be used for commercial purposes.
Both deep and shallow aquifers are used as sources of drinking water. Industrial, commercial, and
retail establishments; recreational facilities; service industries; and residential areas exist within the
site boundaries. New housing construction on reworked mine land occurs frequently. In addition,
schools, hospitals, and nursing homes are located within the site’s boundaries (Reference 1, pages 3
and 4).
According to EPA Region VII, negotiations for the Remedial InvestigationlFeasibiity Study under an
administrative agreement began with 15 Potentially Responsible Parties (PRPs) on March 7, 1991,
and may continue into June 1991. Field activities are expected to begin within the last quarter of
1991. Thus, no determinations have been made regarding site remediation.
OPERATING HISTORY
Lead and zinc ore deposits were discovered in the Tn-State Mining District in 1838. Mining began
in the area around 1848 and continued until the late 1960’s. Between 1850 and 1950, the site
generated over $1 billion in revenue (Reference 1, page 1; Reference 2, page 2-1). As many as
4,000 shallow subsurface mines and some strip mines were worked in the area until 1970 when all
commercial mining had ceased. Because the mines were shallow and of limited size, as one location
became depleted, the operation moved to a new area (Reference 1, page 2).
Mining activities at the site involved mining crude ores and milling these ores to produce lead and
zinc concentrates. Ore-bearing rock was crushed and ground into a fine gravel. Then the separation
of mineral from the crude ore was accomplished through a jigging operation. Tailings (also called
chat) were skimmed from the jigging table and discarded in large piles (Reference 1, page 2;
Reference 2, page 2-1). Waste products from the processing were removed and placed in large
tailings piles. Barren rock containing no valuable minerals was also discarded in piles (Reference 2,
page 2-1).
SITE CHARACTERIZATION
Contaminants from the site spread over a wide surrounding area by surface-water flow, ground-water
migration, and atmospheric dispersion (Reference 1, page 3). Heavy metal contamination of ground
water, surface water, and sediment has been documented in the area. The environmental pathways of
3
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Oronogo-Duenweg Mining Belt
concern at the site are contaminated ground water, surface water, sediment, surface soil, and certain
components of the aquatic and terrestrial food chain (Reference 1, page 5).
Ground Water
Two aquifers are used for drinking water at the site. The shallow aquifer is encountered near land
surface and extends to depths as great as 500 feet in the Joplin area. The deeper aquifer is
encountered at a minimum depth of 300 feet, and extends to depths as great as 1,800 feet. The
deeper aquifer is separated from the shallow aquifer by relatively impermeable shales; however,
hydraulic connection between the shallow and deep aquifers is believed to exist (Reference 1, pages 3
and 6; Reference 3, pages 5, 7 and 12). Specifically, leakage of ground water from the shallow
aquifer to the deeper aquifer may occur (Reference 1, pages 3 and 6). In addition, according to EPA,
some of the mining pits, shafts, and boreholes may provide conduits by which contaminants can
migrate from the shallow aquifer into the deeper aquifer.
Ground-water sampling revealed that lead concentrations in the shallow aquifer range from Not
Detected (ND) to 79 parts per billion (ppb). Zinc concentrations ranged from 130 to 8,000 ppb.
Cadmium concentrations ranged from ND to 27 ppb (Reference 2, page 6-1). The variation in
contaminant levels may be due to differences in the construction, depths, location of wells, and/or
changes in ground-water flow rates. Water-quality degradation is caused when subsurface sulfide ores
are exposed to an oxidizing environment. Oxidation of metal-sulfide minerals and subsequent
dissolution and hydrolysis of soluble sulfates in tailings piles produces sulfuric acid and releases
metals into the surrounding environment. Precipitation of metals occurs as the acid is neutralized by
calcium carbonate in the native rocks (Reference 2, page 2-1).
Surface Water and Sediment
The major drainage feature of the area is Spring River. Turkey Creek, located at the southern end of
the site, and Center Creek, located within the northern portion of the site, are hydraulically connected
with the shallow aquifer, and are major tributaries of Spring River. These two creeks establish the
two drainage areas on which the site is located. The Center Creek Drainage area, located northeast
of Joplin, drains the northern portion of the site, and the Turkey Creek drainage area, located
immediately north of Joplin, drains the southern portion of the site. In addition, drainage channels
constructed in the early 1900’s to divert rain and mine water away from the mining operations now
act as tributaries to Center Creek during rainy periods (Reference 3, page 5).
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Mining Waste NPL Site Summary Report
Downstream sediment samples collected from Center Creek contained levels of zinc, lead, and
cadmium that were elevated relative to background samples (Reference 2, page 6-1). An EPA Field
Trip Report for the site notes that not all contamination should be attributed to mining activities
because of the possible presence of local naturally highly mineralized areas (Reference 2, pages 6-1
and 6-2). According to EPA, their findings will be documented in a Remedial Investigation Report
and Feasibility Study at the conclusion of field investigations.
The U.S. Geological Survey’s (USGS’s) investigation at three main surface water bodies that serve to
drain area tailings piles (Center Creek, Turkey Creek, and Short Creek) found that chromium, cobalt,
mercury, nickel, and silver were present in concentrations similar to those existing in the creeks
upstream of the piles. Aluminum, iron, and manganese were found in higher concentrations, but are
generally not harmful to aquatic life in the creeks. Concentrations of zinc, lead, copper, and
cadmium were also present in higher concentrations, which are harmful to aquatic life (Reference 3,
pages 15 and 16).
An August 1977 report prepared by the USGS details the uEffects of Lead and Zinc Mines and
Tailings Piles on Water Quality in the Joplin Area, Missouri (Reference 3). The report found that
average concentrations of iron, manganese, cadmium, and zinc in mine waters all exceeded
recommended drinking water standards (Reference 3, page 7).
Surface Soils
Soil contamination has not been investigated at the site. Nevertheless, it is expected to exist on (and
around) the tailings piles. Airborne transport of dust has probably also contributed to soil
contamination (mining, machining, and smelting operations can produce particles small enough to be
transported in the air). None of the tailings piles has been stabilized, and the waste materials have
been used to backfill mine shafts, for road construction, and in other unspecified ways (Reference 1,
page 5).
Bipta
Although biological media have not been sampled, environmental fate data suggest that zinc and
cadmium may bioaccumulate in aquatic systems, lead may bioaccumulaxe in some shellfish, and
cadmium may be taken up by edible plants (Reference 1, page 5).
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Oronogo-Duenweg Mining Belt
ENVIRONMENTAL DAMAGE AND RISKS
A Risk Assessment has not yet been performed for the site. However, public health implications of
the site have been discussed in the U.S. Department of Health and Human Services’ Preliminary
Health Assessment for the site (Reference 1).
The most important human exposure pathways for the site are believed to be ingestion of
contaminated ground water and suthce water; inhalation of airborne contaminated dust particles;
ingestion of contaminated soil by children in residential areas; and ingestion of contaminated aquatic
organisms and of foodstuffs grown in contaminated soil. Dermal or mucous membrane contact is
possible but unlikely (Reference 1, page 6).
The documented contamination of ground water, surface water, and sediments with heavy metals
could potentially adversely affect the surrounding populations. Within the site boundaries are
industrial, commercial, retail, and service establishments. There are also residential and recreational
areas onsite. In addition, hospitals, nursing homes, and schools are all present onsite, thereby
exposing potentially sensitive populations (sick, elderly, and children) to contaminants (Reference 1,
page 6).
Preliminary risk calculations indicate that excessive exposure to zinc, cadmium, and lead may be
occurring for residents in the Oronogo-Duenweg Mining area (Reference 1, pages 6 and 7). In
addition, the State of Kansas has conducted several health surveys indicating a high incidence of
tuberculosis and lung cancer among area residents according to EPA. Missouri has also started to
examine lead levels in the blood of local individuals.
Surface water at the site, specifically Center Creek, is used for fishing. In addition, surface waters
potentially affected by the site may be used for crop irrigation, livestock watering, commercial
purposes, and recreational purposes. Consequently, public health risks include the risk of exposure
through the foOd chain and recreational activity (Reference 1, pages 3 through 5).
Individuals in the small towns of the Oronogo-Duenweg area (Webb City, Oronogo, Duenweg, and
Carterville) primarily obtain their drinking water from municipal wells screened in the deeper aquifer.
An estimated 1,500 people living outside of these Towns obtain their water from private wells tapping
the shallow aquifer (Reference 1, pages 3 and 6). Ground-water samples collected in November 1988
contained concentrations of lead and cadmium that exceed EPA proposed Maximum Contamination
Levels (Reference 1, page 8). A municipal water supply well within the Site was abandoned some
time after 1972 when it began producing water with high concentrations of dissolved solids. The data
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Mining Waste NPL Site Summary Report
for this well indicate that contamination of the deep aquifer with mine water may have occurred
(Reference 3, page 13).
Ingestion of the contaminants present at this site (zinc, cadmium, and lead) can cause stomach
irritation, kidney damage, liver damage, brain and central nervous system damage, harmful effects to
blood, and damage to the reproductive system. Excessive zinc concentrations are thought to
contribute to the production of cancerous cells and can block the body’s ability to absorb other
important minerals. Exposure to high levels of lead can lead to fetal damage, including preterm
birth, reduced birth weight, and reduced intelligence in later life (Reference 1, page 6).
REMEDIAL ACTIONS AND COSTS
EPA anticipates that the Remedial InvestigationlFeasibility Study will be started in the last quarter of
1991. Consequently, remediation alternatives have not been developed and the estimated cost for
completing site remediation has not yet been determined.
CURRENT STATUS
EPA Region V I I and the PRPs are presently in the process of negotiations for planning the Remedial
Investigation/Feasibility Study. The field activities for the Remedial Investigation are expected to
begin in the final quarter of 1991. A Record of Decision is expected in 1993.
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Oronogo-Duenweg Mining Belt
REFERENCES
1. Preliminary Health Assessment for Oronogo-Duenweg Mining Belt, Jasper County, Missouri,
CERCLIS No. MDD980686281; Department of Health and Human Services and ATSDR;
June 18, 1990.
2. Final Report for Tn-State Mining Area, Joplin, Missouri, TDD-R-07-8601-12A; EPA Region VII;
June 27, 1983.
3. Effects of Abandoned Lead and Zinc Mines and Tailings Piles on Water Quality in the Joplin
Area, Missouri, USGS Water Resources Investigations 77-75; James H. Barks, USGS;
August 1977.
8
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p
RECEiVED
JUN22 1990 PRELIMINARY
PREP SECTION Health
Assessment
for
ORONOGO-DUE.WEG MINING BELT
JASPER COUNrI’, MISSOURI
CERCLIS NO. MDD980686281
JUN18 1990
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Mining Waste NPL Site Summary Report
BIBLIOGRAPHY
Department of the Interior and U.S. Department of Mines. A Mining Research Contract Report:
Study of Stability Problems and Hazard Evaluation in the MLSSOUri Portion of the Tn-State
Mining Area. April 1983.
EPA. Documentation Records for Hazard Ranking System, Jasper County Mining Area, Joplin,
Missouri. Undated.
EPA Region V I I. Potential Hazardous Waste Site: Preliminary Assessment, Tn-State Mining
(Oronogo-Duenweg Center Creek Area), Missouri. February 24, 1986.
EPA Region VII. Potential Hazardous Waste Site: Preliminary Assessment, Tn-State Mining (Shoal
Creek Area), Missouri. February 24, 1986.
EPA Region VII. Potential Hazardous Waste Site: Site Inspection Report, Joplin Tn-State Mining
(Oronogo-Duenweg Center Creek Area), Missouri. February 24, 1986.
EPA Region VII. Potential Hazardous Waste Site: Site Inspection Report, Joplin Tn-State Mining
(Shoal Creek Area), Missouri. February 24, 1986.
MDNR, Division of Environmental Quality. Census of Missouri Water Supplies. May 1982.
Neenan, Guy. Atmospheric Transport of Lead from Mill Tailings in the Tn-State District;
November 11, 1982.
9
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st 1
The Oronogo-Duenweg Mining Belt site, Jasper County, Missouri. has been
proposed by th. U.S. Environmental. Protection Agency (EPA) for .nc1usLon
on the National Prion.ciss List (NPL). Referred to as the Missouri.
por on of the Tn-State (Missour2., Kansas, and Oklahoma) M2.n .ng DLs:r ,
the si.:e comprises approximately 20 square m .les and was the locat .on of
the most concentrated m .rting effort in the Tr -Sta:. Dis:r .ct. As a
result of commercial zinc and lead mining operations that occurred fron
about 1850 until the late 1960*, large open p2.ts (some fLlled wLth a:er)
:a .lings (called chat) piles, open vertical shafts, and subsurface
horLzoncal mining shafts exist throughout the area. Shallow groundwater.
surface water, sediment, and surface soil are contaminated wLth heavy
metals (zinc, lead, cadsium, and nickel). Munic .paljc .es in the area use
both surface water and a deep aquifer for water supplies; Lndivjdual
household.s outsida these centers rely on a shallow aquifer for water.
Based upon information reviewed, the Agency for Toxic Substances and
Disease Registry (ATSDR) has conclud.d that this site is of public health
concern because of th. risk to human health resulting from probable
exposure to hazardous substances at concentrations that may result in
adverse human health effects. As noted in the Human Exposure Pathways
SectIon below, hi- en exposure to heavy metals may be occurring and may
have occurred in the past via ingestion contaminated groundwater, soil,
sediment, and inhalation of soil and sediment particiss suspended in a .r
Levels of lead and ca iua exceeding the EPA proposed Maximum Contam .nan:
Level (MCI..) hay, been documented in the fey wells sampled. Othet
environmental pathways for which there are no data may represent
additional exposure routes. Recommendations for soil and a r sampling a 4
a well survey, as v.1]. as a suggestion for developing a data base for
accidents involving the physical hazards remaining from the mining
operations, are presented.
BACICCROUND
A. SITE DES .IFrI0N AND HISTORY
The Tn-State Mining District comprises approximately 2,400 square miles
of th. adjoining areas of three states--Kansas, Missouri, and Oklahoma.
After the discovery of valuabl, ore deposits in 1838, coercial, mining
and smelting ven area began in th. .IoplLn, Missouri, area in 1848. During
the century spanning 1850.1930, this area produced 30 percent of the zinc
and 1.0 percent of the lead used in the United States. Almost 4,000 mostly
shallow, subsurface •Lnss and a few strip mines were active at one time or
another, mining an estimated 500 million cons of ore. In the late 1950s,
production declined, and by 1970 all. commercial mining had ceased.
Because ore dsposit.s vere located close to the surface, and transportation
and labor were abundant, most mines in the area were shallow and of
limited size. Thus, they became unproductive in a relatively short perLod
of time (5-10 years). When this happened, the thdepend.nt mine
Page 1
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and mill plants would moVe tO another location and sink another shaft.
Such a prospect hole, if successful, would be mined in vertical and
multiple horizontal directions until it too becam. depleted. As a result,
the Jasper County.Joplirt area is p.rmeat.d with chat piles (the rema ns of
milled ore), waste rock piles (low.grade ore, soil, and rock), open pi
(up to “00 feet deep and filled with varying amounts of water), subsidence
areas (where mine shafts have cellaps.d), and potential subsidence areas
Th. mined areas in the tn-stat. are shown in Figure 1. Figure 2
illustrates th. portion of th. mined area ovn as the Oronogo-Duenueg
Mining Belt. At this time, the majority of investigative activity has
centered on this part of the mined area, and the Hazard Ranking Score was
based on information obtained from this area. It is our understanding
that the EPA, during its Remedial Investigacion/Feasibiliry Study process
may consider additional portions of the tn-state mining area as will.
There are two drainage areas associatsd with the Oronogo.Duenweg Mining
Belt, the Center Creek drainage area located northeast of Joplj . which
drains the northern portion of the mining belt, and the Turkey Creek
drainage area, which is imeediately north of Joplin and drains the
southern portion of th. mining belt. There are an estimated 4.6 square
miles o.f tailings in th. Joplin area, with about 2/3 in the Center Creek
Drainage area. Towns and privat, residences are located throughout the
mining area.
Important surface water features in the area include the Spring River.
which is the main drainage channel in the area. Major tributarie4 include
Turksy Creek, Center Creek, and Shoal Creek, which are in hydraulic
connection with the shallow groundwater. In addition, ntmerous drainage
channels were constructsd in th. early 1900. to divert rain and mine
waters away from important production shaft areas. These channels remain
as wet-weather branches to Center Creek.
The shallow aquifer consists of ch.rty limestone, and the deep aquifer
consists of dolomite and sandstone. A relatively impermeable, silty
limestone and shal. layer separates th. shallow and deep aquifers. The
shallow aquifer reaches land surface in some places and extends as deep as
490 feet in other places. Generally, the shall?v aquifer begins 30 to 100
feet below ground surface. Th. deep aquifer is reached at a minim of
330 feet and extends as deep as 1,800 feet.
More information on the history of mining in the Joplin area and a
detailed description of most of th. major areas of mining activity can be
found in referenc. 1.
3. SITE VISIT
Personnel fro. the Agency for Toxic Substances and Disease Registry
(ATSDR) conducted a site visit on March 20, 1989. This included a
self-guided automobile tour, as d.scrib.d in reference 1. No additional
information was obtained other than that provided in the docunents
reviewed.
Page 2
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C. CO *ftJN y HEALTH CONCERNS
No co ufli:y health concerns have been reported to ATSDR.
Dt WCRAPMICS LAND L’SE. AND ?JATL.’RAL R Spt ’RC!
Surface water, including Center and Shoal Creek., and pit water, nay be
used for crop irrigation, livestock watering, and sport fi.shi.ng. Sone
pits have commercial uses; at least one is used as a SCUBA diving t ai .g
facility. Sam. pits are larg. enough to be part of recreational parks ar d
are used for swimming and boating.
The city of Joplin obtain., its wac.r from Shoal Creek, which is located
south of Jopith. Figure 1 illustrates that some mining had occurred
upstream of this area. Smallsr tovn.s in the Or oflogo..Dusnweg aria (Webb
City, Oronogo, Duenweg. Cartervills) use the deep aquifer as the primary
source of drinking water. Psopl. living outside thes, small towns use
private wells see in the shallow aquif.r. According to one estimate, the
population using shallow groundwater for its do estit water supply numbers
1,500. The de.p aquifer reportedly is separated from tb. shallow aquifer
by impermeable shales that appear to form an effective aquacluds. Leakage
from th. shallow aquifer to th. deep aquifer may occur as a result of
recharge.
The huaa activities that take place vithi the site boundaries involve
industrial, Commercial, and retail, establishments, recreational
facilities; service industries; and residential areas. Within the site
boundaries there are Potentially sensitive pøpulaeions, such as children,
patients, and the elderly at schools, hospitals, and nursing homes. New
housing construction on reworked mine land occurs frequartely,
ENVIRpN 4FJrrAL CONTAMINATION AND 0TH R HAZAR.DS
Th. generally accepted concepts of on. and off-sit. contamination are
diffieult to apply here, because of th. very large area under evaluation
and the possibility that contaminants may be spread widely by
surface-water flow, groundvater migration, and Itmospheric dispersion.
For the purposes of this PrelL in*ry Health Assiasment, we will consider
the 2 Osquare.sjl. area dmljrteated in the site map Specifically and the
Tn-State Mining District in general as bsing subject to the public health
evaluation process. Accordingly, all th. date collected relative to this
site will be considered as on-site data.
In addition to the heavy metals listed in Table 1, nickel and mercury were
found also. However, th. reported concerteracions of th.se latter two are
believed to be sufficiently low that we do not feel that these metals are
of public health conce at this time.
Page 3
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A. ON-SITE CONTAMINATION
The data collected so far in this evaluation are su arjz.d in Table 1.
which utclud.s the environa.ntal media and concentration ranges.
Tabi. 1
On-site concentratjon of environmental conta j ncs
Oronogo-Duenw.g Mining Belt, Missouri
ENVIRON ( NTAL SOURCE SUBSTANCE CONC IRATIoN RANGE
August 1976
Groundwater zinc 0.02 8.8 ppm
Surface water zinc 0.5 35 pp
cadmit 0.0 0.06 ppm
lead 0.0 - 1.3 ppm
February 1986
Private veils zinc 0.1 - 8 ppm
cadsit. 0.01 0.03 pp
lead 0.08 ppm
Sediment zinc 39,000 ppm
cadajia 4 250 ppm
lead 66 - 7,300 ppm
August 1986
Privat. veils zinc 0.2 11 ppm
cadstia 0.03 0.04 ppm
lead ND*
February 1938
Private veils zinc 0.05 - 9.1 ppm
cadmi ND • 0.04 ppm
L.ad ND - 0.04 ppm
November 1988
Private v.lis zinc ND - 2.5 ppm
cadmium ND - 0.02 ppm
- lead ND - 0.05 ppm
*ND: nondatsctabt.
B. QUALITY ASSURANCE AND QUALITY CONTROL
Litti. information was provided about quality assurance and quality
control. We assume that the date are of sufficient quality for th.
purposes of this Pxeli.inary Health Assessment.
C. PHYSICAL. AND OTRft HAZARDS
Remains of the mining activities covr so vast an area that public
access restrictions, such as fencing or posting, would be of little
use. Results of a U.S. Bureau of Nines survey in 1983 shoved that
over 1,500 open mine shafts and nearly 500 subsidence features were
in the Tn-State district, with 124 in Missouri. Accidents to people
and livestock, 4 aaau to buildings and roads above shaft areas and
Pag.4
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underground mine workings, have been repor , . However no
Confj a:jons or statistical information are available.
PA WAYS A. 4ALYS
A. Z VIRO AL PATHWAyS (Fats and Transport)
M .nLrtg and milling process, 5 increase the aOount of heavy metals
available for diSso1utjo by decreasing th. ore particle size and
increasing the surface area of the particle. When ths ores contain
sulfid es , as do sphal.rjt , (zinc sulfide) and galena (lead sulfide)
do, acidic solutions can form as groundwater contacts exposed ore or
chat or as rainwater percolates through the piles. Increased contact
time results in the solution of greater amounts of lead, zine, and
sulfat, after oxidation, thus causing groundwater and surfac, water
contamination Solutions with long residence times may become highly
acidic.
Surfac, water migration results in the movement of sediment
conc infng small wascs.or, particles deposited on th, land surface.
In addition, the mining and machining (milling) of ore results in the
formation of smaller and smaller particles, some of which can become
airborn, readily. Smelting causes the formation of even smaller and
more aerodynamic particles.
Heavy metal contamination of groundwac, , surface water, and sediment
has been documented in the area. Although surface soil contamination
has not been confirmd by sampling, it undoubtedly exists on and
around th. chat piles and probably in surrounding areas affected by
atmospheric dispersion of dust. For th. meat part, none of the piles
hav, been stabilized. In addition, vast, material has been used in
coerc, as road fill and perhaps in other ways. Some backfill in g of
mine shafts has occurr.d.
Surfaàe waters, notably Shoal and Centat Creeks, are used for
fishing, Zinc and cadat a btoaccumulat. in aquatic systems. Laad
does not appear to bioaccumulat. significantly in most fish, with the
except o of sOme sb.Llfjsh (mussels). Cadmiumean be eak.n up by
many edible plants; other metals say be transported on improperly
washed produce. The levsls of acidity (pH) in groundwater and
surface water have not been reported.
Therefore, the environmental pathways of concern at this site ar•
contaminated groundvac.r surfac, eater, sediment, surface soil, and
certain components of th. aquatic and terrescrjaj. food chain.
3. HUMAN CPOSURE PATHVAYS
Several population centers and private residences are located within
the boundaries of the Missouri mining area. Any activity that
exposes persons the environmental media listed above can be
Page 5
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considered a potential human exposure pathway. Most important of
these potential human exposure pathways are ingestion of contam .nated
groundwater and surface water, inhalation of airborne con am taced
dust particlss. ingestion of contaninaced soil by children in
residential areas, and ingestion of contaminated aquac2.c organ isms
and of foodstuffs grown in contaminated soil. Dermal or mucous
membrane contact with highly acidic water may be important also, but
this is unlikely to occur chronically because symptoms are readily
apparent.
PUBLIC HEALTH IMPLICATIONS
Ingestion of media containing heavy metals is the important route of
human exposure here. The shallow groundwater is used as a source of
drinking water for the approximately 1.500 p.rsons who are not on
municipal water systems. Municipal systems in the mining area use
the deep aquifer. The deep aquifer may be hydraulically connected to
the shallow aquifer and subject to contamination. The some of the
pits may extend into the deep aquifer and provide a conduit for
contamination of the deep aquifer. Depending on their concentration,
heavy metals may cause irritation of the stomach (zinc and cadmium),
kidney A. ge (cadmium and lead), liver damage (cadmium), brain and
central-nervous-system 4 -g. (lead), effects on th. blood (zinc and
lead) arid reproductive system (cadmium and lead), and possibly high
blood pressure (cadmium and lead) if ingested.
The important health effect of excess zinc (zinc occurs naturally in
drinking water and many foods) is its interference with the body’s
ability to absorb and use other essential minerals such as copper and
iron. No studies have shown zinc to b. associated with the
production of cancer. In the United Statas, the average daily thtaks
of zinc through th. diet ranges from 7 to 16 milligrams per day.
Using th. highest level, of zinc measured in groundwater (11 ppm) and
assuming a water intake of 2 liters per day for an adult, we can
estimate an intake of zinc from water alone of 22 mg p .r day
(equivalent to a dose of 0.3 mg/kg/day for a 70-kilogram adult).
Although the health effects of long-term exposure of humans to
drinking water containing zinc at this Level are not known, 0.3
mg/kg/day is about 3 times the lowest estimated No Observed Adverse
Effect Level (NOAZL) reported in (10). Coupled with as yet unknown
concentrations in air, food, and soil, excessive exposure to zinc may
be occurring to residents of b. Oronoge-Duenweg Mining area.
Exposure to lead is particularly dangerous for the f.cus- -because it
is highly sensitive during development- -and for young
children• -because they ingest more lead through normal mouthing
activities, absorb more of the lead they ingest. and are more
sensitive to its effects. Exposure of a woman during pregnancy is
important because lead can transfer to the fetus, and result in
pretera birth, and reduced birth weight. Reduced intelligence
quotients (IQ) have been reported in children.
Page 6
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1(idney tumors have been reported in laboratory animals fed large
doses of lead; the evidence is insufficient to suggest that lead
causes cancer in humans, and occupational studies have not supported
any such causal relationship. As a toxicant serving no known
physiological requirement, lead at any level in the bndv s
unnecessary. Current scientific thinking holds that there may be a
risk of some adverse health effect at any level of lead exposure,
even though current epidemiologic and analytic methodology may not be
sensitive enough to measure these effects. In most of the studies on
lead effects in humans, data are reported in terms of blood lead
levels (micrograms lead/deciliter of blood (ug/dL). Typical blood
lead levels in children, derived from intake calculations Considering
all routes of exposure (air, food, beverages, water, and soil
ingestion), range from roughly 3 ug/dL in the least exposed children
to 17 ug/dL in the highest exposed children. Using the data of
Pocock, et al. (13), the blood lead level resulting from ingesting
groundwater at the highest concentration reported for this site (0.08
ppm), would be approximately 4.8 ug/dL, or on the low end of the
exposure spectrum. On the other hand, the average baseline intake of
lead by 2-year-old, non-pica, non-urban children has been estimated
to bs 46.6 ug/day, with 25.1 ug from food, water; and beverages, 0.5
ug from inhaled air; and 21 ug from ingested dust. Considering only
the groundwater at this site, the exposure would be 40 ug/day which,
when added to the as yet unknown levels of exposure from inhaled air,
inhaled and ingested dust, and ingested soil or food, could indicate
excessive lead exposure for children and perhaps adults in the
Oronogo-Duenweg Mining area.
The health effect of primary importance from cadmium ingestion is
kidney injury (kidney stones). Inhalation of airborne cadmium may
cause lung disease, including cancer. Cadmium is a common element;
typically, the most important source of cadmium exposure for humans
is ingestion of food. Consumption of 15-30 ug/day is common.
Long-term uptake of up to 350 ug/day for an adult is believed to pose
relatively little risk of causing injury to the kidney or to other
tissues. Consumption of groundwater contaminated with 0.04 ppm
cadmium would result in an intake of about 80 ug/day. Exposure from
groundwater alone may pose a public health problem, since levels in
excess of the Maximum Contaminant Level (0.01 ppm) have been
documented. As yet unknown contributions from inhaled air and dust
and ingested foodstuffs and soil may result in excessive cadmium
exposure for residents of the Oronogo-Duenweg Mining area.
DNCLUS IONS
Eased upon information reviewed, ATSDR has concluded that this site
is of public health concern because of the risk to human health
resulting from probable exposure to hazardous substances at
concentrations that may result in adverse human health effects. As
noted in the Human Exposure Pathways Section above, human exposure to
heavy metals may be occurring and may have occurred in the past via
Page 7
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ingestion and inhalation of contaminated groundwater, soil, sediment
and air. The most recent groundwater sampling data available to
ATSDR (November 1988, ten wells) shows lead and cadmium exceeding EPA
proposed MCLs.
‘o ta are available with which to evaluate the pctcntjal public
health impact from air and soil pathways.
RECO ’ EN’DATI0NS
In accordance with the Comprehensive Environmental Response,
Compensation and Liability Act of 1980 (CERCLA) as amended, the
Oronogo-nuenweg Mining Belt site has been evaluated or appropriate
follow-up with respect to health effects studies. Since human
exposure to on-site contaminants may currently be occurring and may
have occurred in the past, this site is being considered for
follow-up studies. After consultation with Regional Environmental
Protection Agency staff and State and local health and environmental
officials, the Division of Health Studies, ATSDR, will determine if
follow-up public health actions or studies are appropriate for this
Site.
The following recommendations are offered:
1. The particle size distribution of the chat piles should be
determined to help predict the potential inhalation exposure.
2. Heavy-metal concentrations in soil should be determined.
Particular attention should be paid to residential and other
high-contact areas, such as schools and playgrounds.
3. A data base should be considered for the accidents and injuries
resulting from the open mine shafts and other physical hazards
remaining from the mining operations. Whether some sort of
intervention strategy (such as posting or notification by mail)
is needed could be based on the conclusions drawn from these
data.
4. Considering the extensive use of the grouri vater in the area, a
wider program of private well sampling should be undertaken to
characterize exposures. In addition, irrigation wells, private
wells, or surface water bodies that are used as a source of
water for livestock, gardens, or crops should be identified.
Monitoring may be necessary to characterize the potential for
bioaccumulatjon of heavy metals in livestock, crops, other farm
produce, or garden foodstuffs.
5. Further sampling should be performed in the deep groundwater,
- especially in the area of the deeper mine pits, to determine
whether the deep aquifer has been affected.
Page 8
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Oronogo-Duenweg Mining Belt Mining Waste NPL Site Swnmary Report
Reference 2
Excerpts From Final Report for Tn-State Mining Area,
Joplin, Missouri, TDD-R-07-8601-12A;
EPA Region VI I; June 27, 1983
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: _C r3
DP J
L\.I tid Iw
FINAL RE ORT FOR
TRI-STATE MINING AREA
JOPLIN, MISSOtJRI
TD -R—O7—86O1—12A
June 27, 1986
Subnitted to: Paul E. Doherty, APR3
Prepared by: Region VII REM/FIT
Task Leader: Steven Vaughn
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SECTION 2: SIT! HISTORY
Coi n ercial development of the mnieral resources of southwestern
Missour began tout 1650 and soread into southeastern ansas and
nort’ieastern Oklahoma 1 forming the Tn—State District with Jopliri as
the urban center. The value of the Tn—State mineral production from
l85O to 1950 exceeded one billion dollars, and until 1945 the region
was the world’s leadtrg producer of lead and zinc concentrates, ac—
counting far- one—half of the zinc and one—tenth of the lead produced
in the United States. 3y 1950, most of the rich ores had be.n
extracted, and minin* and milling oo.rations declined during the
1950’s and ceased in the 1960’s (Ref. 2).
The mining involved bringing the crude ores to the surface where
the ores were milled into lead and zinc concentrates. !arren rock was
discarded in piles while the ore—bearine rock was crushed and ground
into fine gravel. The minerals were separated from the rock by a
jt girtg process and the waste products (tailings) skimmed off and
discarded in large piles (Ref. 2).
Spha lerite (sine sulfide) and galena (lead sulfide) were the most
important economic minerals in the Joplin area. Other minerals
commonly associated with zinc emd lead were not economic to mine, such
as pyrice, marcasite (both iron sulfides), dolomite, calcite, cPtert,
and jasneroid (Ref. 2). D. radarion of water quality is associated
with the removal of the sulfide mineral, from the subsurface reducing
environment. Oxidation of insolubli metallic—sulfide minerals in the
mines and tailinge to a soluble form and subsequent solution and
hydrolysis of these soluble sulfates produces sulfuric acid and
liberates metals. Rovev,r, neutruligation of the acid by calcium
carbonate in the r cka ultimately results in high concentrations of
calcium, sulfate-and zinc in solution. Due to the insolubility of
most other mptals, rs id prec pitstion will occur (Ref. 2).
2—1
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SEC t0N 6: COMCI. .UStONS
Based on the analytical results of the ground ster sample, cot—
lected from our samnling effort, it does not appear that Drevi us
minin* efforts in the Joplin area are hav ng a 1ar . effect an the
quality of the groundwater sampled at tPt t me of sampling. The vari-
ance in concentrations between veils may be due to differ ng well
depths, construction, and location. These reported concentrations nay
also vary with season as groundwater flow rates change. Concentra-
tions in the shallow aquifer ranted from undetected to 79 ppb lead,
130 ppb to 8000 ppb zinc, and undetected to 27 ppb cadmium.
Analytical results of stream sediment samples show high zinc,
lead, and cadmium concentrations associated with the mi int areas
relative to the background samples. In the Shoal Creek drainage area
background sediment sample. contained 66 ppm lead, 750 pm zinc, and
4.20 ppm cadmium. Devu;radient sediment samoles detected lead, zinc
and cadmium concentrations as high u 4300 ppm. 26000 ppm, and 90 ope,
respect ivelv. The Center Creek background sediment samples detected
lead, zinc, and cadalue concentrations of 290 pom, 4700 ppm, and 20
ppm. Dovngradi.nt ..idm.nt samples detected 7300 ppm lead, 39000 ppm
zinc, and 250 pp. cadafu..
It would be very difficult to attribute all these concentrations
strictly to mining •ctiviri.s as the area is naturally highly miner—
alized. Since surface water samples were not taken, at the equeac of
!PA, it is not known the extent to which these sediments affect the
surface water oustity. ue to the near neutral water pH detected at
all sediment sampling locations it ii unlikely that the metals bound
in the sediments would_be liberated into solution.
-------
It is difficult to determine how es ch of an effect, if any,
DTCVIOU S i ning has had on the .JODlin Tn—State area due to the fact
chat the natural setting does not exist today. ‘lineralizatjon of the
area may be localized making it difficult to determine appropriate
background areas. The background areas used in this investigatj o may
be outside of these highly mineralized areas, therefore would not be a
natural representation of the nearby mining areas. To document the
effects Drevious mining has had on the Tn—State Mining area would
require a i.ach re extensive study and sampling effort than requested
during this investigation.
S
6—2
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4
Oronogo-Duenweg Mining Belt Mining Waste NPL Site Summary Report
Reference 3
Excerpts From Effects of Abandoned Lead and Zinc Mines
and Tailings Piles on Water Quality in the Joplin Area, Missouri,
USGS Water Resources Investigations 77-75;
James H. Barks, USGS; August 1977
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r
EFFECTS OF ABANDONED LEAD AND ZINC MINES AND TAILINGS PILES ON
WATER QUALITY IN THE JOPLIN AREA, MISSOURI
by James H. Barks
—
U.S. GEOLOGICAL SURVEY
Water-Resources Investigations 77—75
Prepared in cooperation with
the Ozark Gateway Council of Governments
August 1977
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FIGURE 1. L st ó •. Ms n si dy wsi. Tn$%ata Disv t, tha us.a.s .d,s.
- (R.1.1)
August 9, 1990
3
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Water temperature, specific Conductance, pH, alkalinity and dissolved
oxygen were determined in the field. Water temperature was measured w itti
a mercury thermometer to the nearest O.5C (degrees Celsius). Specific
conductance was measured using a portable conductivity meter with temper..
ature compensation designed to express readings in umhos/ at 25’C
(rnicrOmhOS per centimeter at 25 degrees Celsius). The Potentiometric method
was used to measure both the pH and alkalinity. The inflection points in
the titration for alkalinity with 0.01639 normal sulfuric acid were 8.3 and
4.5 for bicarbonate. The azide modification of the Winkler method was used
for dissolved oxygen determinations. The only departure from these methods
was the determination of temperature, specific Conductance, dissolved oxygen,
and pH profiles in mine shafts using an electronic instrument calibrated
according to the manufacturer’s instructions.
GROUND WATER
— vrth e ,rea—’ n’ciade-.the hr1 I qu, er-,n
G: es ss ss 1-age end —the eep req ‘in cherty -do I OC1 tes
The shallow and deep aquifers
are separated by relatively impermeable silty limestones and shale of
Mississippian and Devonian age. A genera1ize section of the geologic
formations and their hydrologic properties is given in table 1, ii, the back
of the, report.
he1low—jfé, at ac,s and extends ds deeo
‘res-5004t (feet)w Brecciated areas generally are highly permeable while
surrounding areas of dense limestone have low permeabilities Mineral
deposits in the brecciated areas were mined at depths from 100 to 250 ft.
The abandoned mines contain large volumes of highly mineralized water.
A potentiometric snap of the shallow aquifer (fig. 2) was prepared from
water levels that were measured in approximately 200 shallow wells and mine
shafts fl September and early October 1976 during a period of little precipj . .
tation and low streainflow. The map Shows the slope and direction of ground-
water movement. Water levels represent the water table except for the few
wells and mines that have water under artesian pressure. ewater t l,
s Jsual y oseto nd•surfaca r streams and Irom -25 to GO Ct
icw larld..; rface away Center and Turkey Creeks are in
,draulic connection with the shallow aquifer and generally act as drains.
r ydrologjc divides generally correspond to topographic divides and movement
of the ground water Is from the divide areas to the streams. Regional
movement of the water In the shallow aquifer is toward the west.
A comparison of the September-October 1976 and June 1966 (Feder and
others, 1969 , p. 28) poteritlometrjc maps Shows that except for the area
north of Duenweg, the altitude of the water table and movement of the ground
water is unchanged. In 1966 heavy pusv ing in the area north of Duenweg
formed a cone od depression and altered the ground-water flow pattern
causing water to flow into the cone to replace water that had been pumped
out. Most of the pumpage stopped soon after the 1966 water—level measure-
ments were made. The 1976 measurements show a recovery of about 100 to
150 ft In water . .table altitude in the Duenweg area. Consequently, the 1976
5
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map does not show a depression in the water table north of Duenweg.
The deep aquifer is reached at a minirmim depth of about 300 ft and
extends as deep as 1,800 ft. Water inthe deep aquifer is under artesian
pressure, but water_level measurements indicate that the potentiometric
surface of the deep aquifer is below that of the shallow aquifer (Feder and
others, 1969, p. 12). This relationship favors downward Seepage of water,
and where faults, fracture openings, and wells connect the aquifers, water
can leak directly from the shallow aquifer to the deep aquifer. Where the
aquifers are separated by the Northview Formation, the Chattanooga Shale, or
both, these shales act as confining beds permitting little water movement.
In 1976 water samples were collected from 14 mines, 21 shallow wells,
and 14 deep wells. Results of analyses of these samples are shown in tables
2, 3, and 4, respectively, in the back of the report. The data are sumarized
in table 5 and figure 3 and discussed under the topics, “Mines,” Shallow
wells,” and “Deep wells.”
Mines
Dissolved-solids concentrations in water from mine drifts are generally
greater than 1,000 mg/L (milligrams per liter). In ground—water recharge
areas (higher altitudes away from main streams) downward water movement
prevents water in the drifts from circulating up into the mine shafts, and
water in these shafts contain less than 500 mg/L dissolved solids. Conversely,
in ground-water discharge areas (lower altitudes near main streams or water
under artesian pressure) upward water movement causes water in the drifts to
circulate up through the mine shafts. This phenomenon is illustrated by the
sketch in figure 4 and by specific conductance, pH, temperature, and dissolved
oxygen profiles (fig. 5) that represent average characteristics for seven
mines (map nos. 101, 102, 103, 106, 107, 108, and 113) in recharge areas and
for three mines (map nos. 104, 112, and 114) in discharge areas. Average
depth to the water surface was 35 ft in recharge areas and 1 ft in discharge
areas. The relation between dissolved solids (DS) and specific conductance
(SC) for water in the drifts and shafts is DS=(0.99XSC)-l2l; the standard
error of estimate is 49 mg/I DS. In table 2, in the back of the report, those
analyses with dissolved-solids concentrations less than 500 mg/I are for
water collected from shafts in ground-water recharge areas. Those with
dissolved-solids concentrations greater than 900 mg/I are for water collected
from drifts in the recharge areas or from shafts in ground-water discharge
areas. All of the analyses were used to compute values shown for mines in
table 5 and figure 3.
Water in limestone rocks is usually a calcium bicarbonate type, but
water in the abandoned mines is a calcium sulfate type (fig. 3), reflecting
the sulfide mineralization.
Average concentrations of dissolved iron, manganese, cadmium, and zinc
in the mine water (table 5) exceed concentrations of 300, 50, 10, and 5,000
i g/L, respectively, recoriTnended as drinking water standards (U.S. Public
Health Service, 1962). Concentrations of other metals in the mine water are
- 7
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well below the drinking water standards. High concentrations of zinc in the
mine water are particularly significant because zinc Is highly toxic to
aquat 4 c animals and some of the mine water reaches the main streams in the
area as discussed later in the report.
Shallow Wells
Many of the 21 shallow wells that were sampled are located between the
flooded mines and Center and Turkey Creeks. Average depth of the wells Is
243 ft. which is a little deeper than most mines in the area.
Water in the shallow wells is generally a calcium bicarbonate type
(fig. 3). Only four of the wells (map nos. 203. 204, 211, and 219) have
water with sulfate concentrations greater than 60 mg/L. Three of these are
in, or very near, mines and the other is probably In Contact with sulfide
minerals. One of the wells (map no. 204), known to penetrate a mine, has
water-quality characteristics similar to the mine water including a dissolved-
solids concentration of 1.190 mgIL, a sulfate Concentration of 560 mg/L, and
a zinc concentration of 8,800 g/L. Water from the other shallow wells is
considerably less mineralized than the mine water.
Metals concentrations in water from the shallow wells are generally low,
except for zinc. Zinc concentrations average 1,100 ug/L and are probably
influenced by galvanized plumbing and (or) local sulfide mineral deposits as
described by Feder and others, 1969, p. 34.
Results of the shallow well sampling indicate that there is not wide-
spread movement of the highly mineralized mine water in the shallow aquifer.
Deep Wells
Water in the deep aquifer is a calcium magnesium bicarbonate type (fig.
and it can be distinguished from water in the shallow aquifer by its lower
mineral content and lower calcium magnesium (Ca:Mg) ratio. The average Ca:Mg
ratio (calcium and magnesium expressed in milliequlvalents) is 23 for water
in the mines, 23 for water In the shallow wells, and 1.7 for water in the
deep wells. The lower ratio for water in the deep aquifer is indicative of
the higher magnesium content of the dolomitic rocks.
TheCa:Mq ratios and concentrations of dissolved solids, sulfate, and
zinc in water fran Webb City Well No. 6 (map no. 305). Webb City Well No. 7
(map no. 308), and Carthage Well No. 1 (map no. 311) indIcate mixing with
water from the shallow aquifer. The water from the shallow aquifer may be
leaking directly into these wells or may be entering the deep aquifer through
faults, fracture openings, or wells that connect the aquifers.
The Oronogo-Duenweg mining belt extends along the east edge of Webb City.
Water from deep wells on the east side of Webb City is more mineralized than
water from deep wells on the west side.
12
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In June 1972 the dissolved-SOlids concentration i water from Webb City
Well Sb. 10 was 840 mg/L. This well IS located near the mining belt and the
high dissolved_solids content indicates the POSsibility of mine-water
contamination of the deep aquifer on the east side of Webb City. This well
has been abandoned as a source of municipal water because of the high
mineralization of the water (Raymond Lawrence, Supt. Webb City Water Dept.,
oral conTnun., 1976).
SURFACE WATER
Center Creek, Turkey Creek, and Short Creek drain about 70, 18, and 5
percent of the mining area, respectively. Some physical and hydrologic
characteristics of these streams are given in table 6. All three streams
flow westward and are characterized by alternating pools and riffles, and
mixed sand, gravel, and boulder bottoms.
The lower part of Center Creek, the largest of the three streams, flows
through the northern part of the mining area and Into the Spring River near
the Missouri-Kansas state line. Most of the baseflow originates in the
headwater area, with little or no increase and some losses In the lower
reach (FeØer and others, 1969, p. 54).
having 4 . tOt-vQlu ofapproxi ,,ately 38 iaifl Ion yd 3 (cubic yards), cover
the ‘ower par.t of ti’e basin (Joseph R. Miller, Ozark Gateway Council of
jovernments, written ccnrun., 1977). Most of these tailings are in the
Oronogo-Duenweg mining belt. Discharges from et least three flowing mines
pnter Center Creek.
Turkey Creek, south of and parallel to Center Creek, flows through the
northern part of Joplin and into the Spring River In Kansas, just across the
state line. It is located in the center of the mining area. ings-pfl
ere -scattered throughout tr.e basin and cover - n rea of about ..500.acres, w tb
a—.t.otaj olumeofab ut1O mil11o?ryd 3 i The flow and quality of water in
Turkey Creek are greatly altered by sewage plant discharge at Joplin,
industrial discharges, and mine—water discharge from at least one abandoned
mine.
Short Creek, south of and parallel to Turkey Creek is a small stream that
originates just west of Joplin. After crossing the state line it flows
4.3 ml (miles) in Kansas before entering the Spring River. Althäügh Short
Creek has a total drainage irei of 78..12 (square miles) only about 7.6 m1 2
contribute to the flow at the state line. ,Mie4ng ‘ectiw 1u .in...the .i&pper part..
oL the -basin have q ‘abouti8SaII--(2g llllon yt 3 ,) of tai4ings. i 1
ca tterad . .Zhe .si rMo.
Tailings Areas
The distribution and size of tailings piles on the surface generally
correspond to the distribution and size of mines beneath the surface. However,
some of the ore was removed from the area for processing and some of the
tailings have been removed to be used for road surfacing and railroad ballast,
or ground Into sand for sand blasting. The greatest concentration of tailings
13
/1 ,
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piles is In the Oronogo—Duenweg mining belt (fig. 6), which is about 2 ml
wide and 10 ml long, reaching from Oronogo to Ouenweq. This mining area is
in the Center Creek basin, except for the southwestern edge which Is In the
Turkey Creek basin. Outside the Oronogo-Duenweg belt the tailings piles
are generally scattered and intermixed with woodlands and farmlands.
iágard I ess- f i- o’oe t4en njn0ff- end seepage from — ii gs ‘O es-i’e ch
emain streams.-elther directly or through natural or man-made drainages ’.
Surface drainage to Center Creek from the Oronogo-Duenweg mining belt
is primarily by Mineral Branch, located in the center part of the belt (fig 1).
It originates southwest of Prosperity and flows into Center Creek at Highway D
about 1.5 ml upstream from Oronogo. Another drainage. Stoutt Branch, origi-
nates in the mining belt southeast of Prosperity, but leaves the mining area
and runs through farmlands and woodlands before entering Center Creek just
downstream from Lakeside. The Sunset mine (map no. 109) and a nearby
unnamed mine (map no. 110) discharge about 1 ft 3 /s of water to Mineral Branch
at Carterville during periods of low flow. Otherwise, Mineral Branch is dry
upstream from Cartervllle and Stoutt Branch Is dry throughout its length
during periods of little or no rainfall, but both carry large volumes of
w4ter during periods of heavy rainfall. These two branches are Important
from the standpoint of the effects of the tailings areas on water quality
in Center Creek.
Rcccz 1n4ussanc..-- L ring the reconcaissance sampling In March 1976 water
j’flowing at eight tailings sites was collected and analyzed to determine the
variation in types and concentrations of major ions and minor elements, as
shown in table 7 in the back of the report. The eight tailings sites are
scattered throughout the area, but most are located in the Oronogo-Duenweg
mining belt. Sources øf the water samples vary from seepage directly Out of
indiv dual tailings piles to flow in ditches draining areas completely
covered by tailings, to flow in ditches draining areas that are only partly
covered by tailings. Water at two of the sites, Mineral Branch at Carterville
and Leadville Hollow near Joplin. Is derived In part from mines that discharge
at the surface. The samples were collected during a period of moderate
rainfall while surface runoff was taking place.
t In table 8 characteristics and dissolved constituents of water from .the
tall 2ags .mmees. maico er,dw*th $ ee .4Oq A3 & .sar4l e co3l acted; from
Center Creek upstream from thi mining area. Water from the tailings areas
is more mineralized than water from Center Creek near Fidelity, and is a
calcium sulfate type rather than calcium bicarbonate. The higher sulfate
concentrations reflect the oxidation and solution of sulfide minerals still
present in the tailings.
Chromium, cobalt, mercury, nickel, and silver are present in tailings
area water at about the same low concentrations as In water from Center Creek
upstream from the mining area. Aluminum, iron, and manganese concentrations
are considerably higher In th. tailings water, but these metals are gener-
ally nontozic to aquatic animals. uMsta that *rS toxlc..to aquatic animils.
15
4 ’)
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Mining Waste NPL Site Summary Report
Palmerton Zinc
Palmerton, Pennsylvania
U.S. Environmental Protection Agency
Office of Solid Waste
June 21, 1991
FINAL DRAFT
Prepared by:
Science Applications International Corporation
Environmental and Health Sciences Group
7600-A Leesburg Pike
Falls Church, Virginia 22043
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DISCLAIMER AND ACKNOWLEDGEMENTS
The mention of company or product names is not to be considered an
endorsement by the U.S. Government or by the U.S. Environmental
Protection Agency (EPA). This document was prepared by Science
Application International Corporation (SAIC) in partial fulfillment of
EPA Contract Number 68-W0-0025, Work Assignment Number 20.
A previous draft of this report was reviewed by Tony Koller of EPA
Region ifi [ (215) 597-3923], the Remedial Project Manager for the
site.
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Mining Waste NPL Site Summary Report
PALMERTON ZINC
BOROUGH OF PALMERTON, CARBON COUNTY, PA
INTRODUCTION
This Site Summary Report for Palmerton Zinc is one of a series of reports on mining sites on the
National Priorities List (NPL). The reports have been prepared to support EPA mining program
activities. In general, these reports summarize the types of environmental damages and associated
mining waste management practices at sites on (or proposed for) the NPL as of February 11, 1991
(56 Federal Register 5598). This summary report is based on information obtained from EPA files
and reports and on a review of one summary by the EPA Remedial Project Manager for the site,
Tony Koller.
SITE OVERVIEW
The Palmerton Zinc Superfund Site is located in the borough of Palmerton, Pennsylvania, at the base
of Blue Mountain and at the confluence of the Lehigh River and Aquashicola Creek (see Figure 1).
Two primary zinc smelters have produced zinc and other metals for machinery, pharmaceuticals,
pigment, and other products. The first smelter, the West Plant, was constructed in 1898, and
produced zinc oxide until 1987. A second smelter, the East Plant, was in operation from 1911 to
1980. The East Plant, the main source of air pollutants, concentrated zinc sulfide ores. Palmerton
Zinc was added to the NPL in September 1983.
Cadmium, lead, and zinc are the contaminants of concern. Approximately 7,000 people live in the
Town of Palmerton. The Palmer Water Company has four production wells, ranging in depth from
200 feet to more than 400 feet at the base of Blue Mountain. The residential water supply for the
Towns of Palmerton and Aquashicola is drawn from this source.
The Palmerton Zinc Superfund Site has four problem areas, and each is being studied as an individual
Operable Unit. These are: (1) the defoliated portion of Blue Mountain near the smelter slag piles;
(2) the Cinder Bank; (3) heavy metal deposition throughout the valley; and (4) the overall ground-
water and surface-water contamination. Only the first two Operable Units will be addressed in this
summary. Operable Units 3 and 4 are still being studied. The interim remedial actions for the first
two Operable Units will be consistent with the comprehensive remedy for the entire Superfund Site.
1
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Palmerton Zinc
FIGURE 1. PALMERTON ZINC SITE
2
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Mining Waste NPL Site Summary Report
The interim remedy for the revegetation of Blue Mountain (Operable Unit 1) is described in the
Record of Decision (ROD). The ROD was signed by the Region ifi Administrator in September
1987. Vegetation damage first appeared m 1951 as isolated patches on the steep, north-facing slope
of Blue Mountain. By 1985, approximately 2,000 acres had sustained vegetation damage. For
assessment purposes, vegetation damage was defined as areas of exposed rock and soil leaving barren,
eroded land visible. The selected interim remedial measure focuses on the establishment of a natural,
eastern forest ecosystem. The estimated cost for implementing this remedial action will be minimal.
The interim remedial action for the Cinder Bank (Operable Unit 2) was signed by the Regional EPA
Administrator in June 1988. Process residues and other plant wastes were deposited on the Cinder
Bank until it had become 2.5 miles long, between 500 and 1,000 feet wide, and up to 100 feet above
the mineral soil layer. In December 1986, it was estimated to contain 28.3 million tons of leachable
metals including lead, zinc, and cadmium. Contaminated leachate percolates down to the ground
water and seeps out of the Cinder Bank. The interim remedial action for the Cinder Bank includes
slope modification, capping, and application of a vegetative cover on the Cinder Bank; construction of
surface-water diversion channels; and a surface-water and leachate-collection and treatment system.
Operable Unit 3 is still in the Remedial Investigation and Feasibility Study stage. It involves the
deposition of heavy metals (mainly cadmium, lead, and zinc) throughout the valley as a result of air
emissions from the smelters. Funding is to be made available during fiscal year 1991 to conduct a
Remedial Investigation/Feasibility Study of Operable Unit 4, which will address the overall ground-
water and surface-water contamination.
OPERATING HISTORY
Palmerton Zinc operated two smelters between 1898 and 1987. The first smelter, the West Plant,
opened in 1898, and produced zinc oxide from zinc silicate ore until its closure in 1987. A second
smelter, the East Plant, was in operation from 1911 until 1980, when primary smelting of
concentrated zinc sulfide ores was stopped (Reference 1, page 2; Reference 2, page 4; Reference 3,
page 1-1). From 1898 to 1967, the smelters were privately owned by the now defunct New Jersey
Zinc Company. In 1967, the smelters were sold to Gulf & Western Inc., which operated the facility
until 1981, when it was purchased by its current owner (Zinc Corporation of America) (Reference 1,
page 1).
The East Plant was constructed for the concentration of zinc sulfide ores. The process consisted of
crushing the ores and removing the sulfur by burning, which replaced the sulfur in the ore with
oxygen to produce a low-grade zinc oxide and sulfur dioxide. The crude zinc oxide was further
3
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Palmerton Zinc
treated by sintering and mixing with coal to convert it to either a relativeLy pure zinc oxide or zinc
metal. The sulfur dioxide was converted to sulfur trioxide and absorbed in a weak sulfuric acid to
produce a merchant-quality sulfuric acid (Reference 3, page 1-1).
Air emissions from the plants contained large quantities of zinc, lead, cadmium, and sulfur dioxides.
The emissions led to defoliation of approximately 2,000 acres on Blue Mountain, and deposited heavy
metals throughout the valley (Reference 2, page 4; Reference 1, page 3). Process residues, other
plant wastes, and municipal wastes were deposited at a cinder bank waste pile located behind the East
Plant (until 1970) (Reference 1, page 6).
SITE CHARACTERIZATION
The ROD (June 1988) indicated that the possible exposure pathways include ground water, surface
water, soil, and the food chain. The contaminants of concern are cadmium, lead, and zinc (Reference
1, page 3).
In compliance with the EPA’s Administrative Order by Consent, dated September 24, 1985, sampling
of all affected media was conducted on behalf of the New Jersey Zinc Company, by R.E. Wright
Associates, Inc. Sediment and surface-water samples were taken during March and August 1986
(Reference 5, page 5-1). Ground-water samples were collected during August 1986 and March 1987
(Reference 5, page 4-10). Flows in both Aquashicola Creek and Lehigh River during the March
sampling period were high due to precipitation and snowmelt, thus characterizing conditions during
the “wet season.” Flows during the August sampling period were much lower, and thus
characterizing the “dry season” (Reference 5, page 5-1).
Blue Mountain
The Blue Mountain Operable Unit is a defoliated 2,000-acre site on the north-facing slope of Blue
Mountain, rising approximately 1,000 feet to an elevation of 1,500 feet above mean sea level
(Reference 1, page 3; Reference 3, page 1-3). The environmental impact of the plant emissions are
obvious to the naked eye. Vegetation is absent and the soil is eroded (Reference 4, page 4-1).
Besides the defoliated vegetation and erosion, the affected area on Blue Mountain is noticeably absent
of microflora, lichens, arthropods, and wildlife species (Reference 2, page 5). A 1972 study by
Nash, an independent researcher, concluded that the richness and abundance of lichen species had
been reduced by approximately 90 percent. In 1984, a study by Beyer, Miller, and Cromartie
reported that the mortality rate of arthropods after 8 weeks in Blue Mountain surface litter was 84 to
87 percent (Reference 4, pages 4-1 and 4-2).
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Mining Waste NPL Site Summary Report
Surface-soil samples collected in the Operable Unit recorded cadmium levels ranging from 364 to
1,300 parts per million (ppm); lead samples ranged from 1,200 to 6,475 ppm; and zinc sample levels
ranged from 13,000 to 35,000 ppm. The maximum levels are up to 2,600 times the typical regional
background levels for cadmium, over 2,000 times the regional background for lead, and over 400
times the regional background for zinc. Depth profiles showed that most metals contamination is
located within the top 6 to 10 inches of the soil. This is because the metals are bound in organic
materials. Water flowing across the defoliated portions of Blue Mountain has eroded the surface and
become contaminated with metals in the soil. The runoff and erosion have carried the metal-ladened
soil into Aquashicola Creek (Reference 2, page 5).
Cinder Bank
Cinders (residue) from the production facilities have been stockpiled along the north side of Blue
Mountain, south and east of the East Plant, since 1913. The Cinder Bank is now approximately 2.5
miles long, between 500 and 1,000 feet wide, and approximately 100 feet above the mineral soil
layer. As of December 1986, the Cinder Bank contained 28.3 million tons of waste material
(Reference 3, page 1-2). The residue materials have been stocked in designated areas based on metal
values. The designated areas are generally divided into boiler house and anthracite coal; horizontal
retort; vertical retort; traveling grate furnace (high and low zinc areas) and Waelz kiln residues; slags;
and Town refuse (Reference 3, page 1-2). As a whole, the Cinder Bank consists of 16 percent
carbon, 2.7 percent zinc, 0.025 percent cadmium, 0.36 percent lead, 0.33 percent copper, and 0.6
ounce per ton indium; the remainder is ash (Reference 3, page 3-2).
Portions of the Cinder Bank Operable Unit smolder continuously, and are posted as fire areas. In
physically undisturbed areas, large cracks have developed and large blocks of partially consolidated
residue occasionally fall from the waste pile. The cracks and the resulting rough surfaces provide
avenues for the infiltration of rain and snowmelt, facilitating leaching of soluble constituents from the
waste pile. In addition, the Cinder Bank has been contoured to a slope of 2 to 1, which is unstable
(Reference 1, page 9).
In runoff and seepage samples taken from the east end of the Cinder Bank, zinc concentrations were
found at background levels ranging from 0.27 to 0.67 milligrams per liter (mg/I) to values as high as
230 mg/I. Increased cadmium concentrations were also highest in this area. At the base of the
Cinder Bank, in seeps and springs, average zinc concentrations have been recorded at 35 ppm, and
average cadmium concentrations were 0.118 ppm (Reference 1, page 9). The ROD indicates that
cadmium concentrations in Cinder Bank runoff were higher than background levels, but the ROD
does not indicate the level of concentration.
5
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Palmerton Zinc
Surface Water
The drainage pattern in the area of concern is toward Aquashicola Creek, a tributary of the Lehigh
River. Aquashicola Creek flows through a buried valley between Blue Mountain on the south and
Stony Ridge on the north. The creek flows southeasterly, and is joined by Buckwha Creek about .5
mile upstream of Harris Bridge and by Mill Creek near the main gate of the East Plant. Aquashicola
Creek joins Lehigh River approximately 1.5 miles southwest of the East Plant (Reference 1, page 4).
The reach of the Aquashicola Creek in Palmerton is classified as a Trout-stocking stream by the
Pennsylvania Department of Environmental Resources (Reference 1, page 4). According to the
criteria of water uses in this classification, the creek should maintain stocked Trout from February 15
to July 31. It should also maintain and propagate fish species and have additional flora and fauna that
are indigenous to a warm-water habitat (Reference 2, page 4).
Significant contributions of zinc, cadmium, and manganese enter Aquashicola Creek from the East
Plant (Reference 1, page 10). Cross-sectional concentration data showed higher zinc and cadmium
levels on the Cinder Bank (south) side of the creek. No significant metal concentrations were found
in Mill Creek, which enters Aquashicola Creek from the north at the East Plant (Reference 1, page
11). Most of the zinc and cadmium is contributed to Aquashicola Creek by ground-water and runoff
sources (Reference 1, page 11). In addition, the ROD estimates that nonpoint sources, such as
ground-water discharge, are responsible for between 80 and 95 percent of metals loadings to
Aquashicola Creek (Reference 1, page 15).
Ground Water
Ground water in the site occurs in both unconsolidated deposits and the underlying bedrock. Specific
conductivity of ground-water samples from seven shallow wells on the East Plant site ranged from
130 to 800 micromhos per centimeter. Calculated dissolved solid concentrations ranged from 85 to
520 mg/I. Generally, water of this quality is acceptable as public drinking water. However, zinc was
detected in all seven wells sampled, and cadmium was found in four of the seven wells sampled.
Zinc concentrations ranged from 0.003 to 3.2 mg/I, and cadmium concentrations ranged from 0.002
to 0.024 mg/I (Reference 1, page 14).
Because of the location and presumed direction of natural ground-water flow from south (Blue
Mountain) to north (Aquashicola Creek), it is likely that the high metal concentrations in the wells
resulted from leachate originating in the Cinder Bank (Reference 1, page 14).
6
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Mining Waste NPL Site Summary Report
Three deep wells (from 200 to more than 400 feet) at the west end of the East Plant on the lower
flank of Blue Mountain were found to have very low concentrations of zinc (the amount was not
given in the ROD). One well had a small concentration of cadmium (the amount of cadmium was not
given in the ROD either). The deep wells have no direct contact with the shallow aquifer or surface
waters (Reference 1, page 14).
Sediments
Samples taken during EPA’s Remedial Investigation show elevated concentrations of zinc and
cadmium in stream sediment samples taken from monitoring stations adjacent to the Cinder Bank, the
East Plant, and on Aquashicola Creek downstream of its confluence with Lehigh River The high
concentrations of heavy metals in Aquashicola Creek and in the Lehigh River are attributable to
discharges and erosion from the Cinder Bank (Reference 1, page 12).
Zinc concentrations in background sediment monitoring stations (location unknown) ranged from 420
to 840 milligrams per gram (mg/g), and averaged 620 mglg. Zinc concentrations at sediment
monitoring stations adjacent to the Cinder Bank, the East Plant, and downstream on Aquashicola
Creek ranged from 6,200 to 42,000 mglg, and averaged 19,900 mg/g (32 times the average
background concentration). The background zinc concentrations in stream sediments from
Southeastern Pennsylvania are generally less than 200 mg/g (Reference 1, page 12).
Cadmium concentrations at background sediment monitoring stations ranged from 2 to 13 mg/I, and
averaged 6 mg/I. Cadmium concentrations in sediment monitoring stations adjacent to the Cinder
Bank, the East Plant, and downstream on the Aquashicola Creek ranged from 39 to 420 mg/I, and
averaged 157 mg/I (26 times the average background concentrations) (Reference 1, page 12).
ENVIRONMENTAL DAMAGES AND RISKS
Neither the RODs nor the Remedial Investigation Report discuss any human health effects associated
with the contaminants of concern, except for those people who consume fish caught in contaminated
water. The contaminants of concern are cadmium, lead, and zinc. Possible exposure pathways are
soil, air, ground water, surface water, and the food chain.
In a February 6, 1987, memorandum, the Agency for Toxic Substances and Disease Registry found
that a potential human health risk exists through the consumption of fish from Aquashicola Creek.
Specifically, the levels of lead and cadmium in the fish present potential health risks to persons who
regularly consume fish caught from Aquashicola Creek (Reference 1, page 15).
7
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Palmerton Zinc
The National Academy of Sciences has estimated the Recommended Dietary Allowance for zinc is 15
milligrams per day. Long-term exposure to excessive levels of zinc (2.1 milligrams per kilogram per
day) could cause a copper deficiency. The human body eliminates zinc through excretion and sweat.
The public has been concerned with the potential health effects of soil and ground-water
contamination and the potential financial impact on the Zinc Corporation of America of any remedial
action costs. Also of concern is the environmental devastation and negative image the barren
mountain projects onto the community (Reference 1, page 16; Reference 2, page 16).
The Aquashicola Creek and Lehigh River are not highly productive sites for benthic
macroinvertebrates but, in reference stations along the Aquashicola Creek upstream of the Cinder
Bank, 29 kinds of organisms were collected. In stations adjacent to the East Plant, conditions begin
to deteriorate with a 4.0-percent reduction in the types of benthic macroinvertebrates, and a 45-percent
reduction in the overall benthic macroinvertebrates population. Changes in the benthic
macroinvertebrate population is attributed to heavy metal concentrations in the runoff from the Cinder
Bank. There was no apparent effect from the Aquashicola Creek’s contamination on Lehigh River
benthic macroinvertebrate populations (Reference 1, pages 12 and 13).
Periphyton populations decreased from 40,000 organisms per square centimeter (organisms/cm 2 )
upstream of the Cinder Bank to 20,000 organisms/cm 2 and 5,000 organisms/cm 2 in the reach adjacent
to the Cinder Bank. This decrease was attributed to Cinder Bank runoff, seepage, and low
chlorophyll concentrations. Periphyton community numbers and composition in Lehigh River were
not influenced by wastes carried by Aquashicola Creek (Reference 1, page 13).
Significant fish mortalities (greater than 10 percent allowable for the control group) occurred in
sampling stations extending from the mouth of Aquashicola Creek to 3 kilometers upstream. This
stretch of the creek receives Cinder Bank runoff and seepage. There appears to be a correlation
between fish mortality and zinc concentrations. Monitoring stations with zinc concentrations of 0.49,
0.71, and 0.87 mg/I had mortality rates of 0, 20, and 40 percent, respectively (Reference 1, pages 13
and 14).
REMEDIAL ACTIONS AND COSTS
The major objective of remedial actions to be taken at the Palmerton Zinc Superfund Site include: (1)
minimizing and restricting direct contact with defoliated areas and the Cinder Bank; (2) reducing the
volume of runon; (3) reducing the volume of runoff; (4) reducing the contamination in runoff;
4
8
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Mining Waste NPL Site Summary Report
(5) collecting and treating leachate; (6) reducing the windborne contaminated emissions; and
(7) reducing particulate erosion (Reference 1, page 16).
Blue Mountain Operable Unit
An interim remedy for the Blue Mountain Operable Unit was established in September 1987. The
selected remedy for this Operable Unit consists of using a mixture of sewage sludge and fly ash to
vegetate the defoliated areas of Blue Mountain. The remedial action presented in the ROD for the
Blue Mountain Operable Unit includes the following activities:
• Constructing access roads in areas targeted for revegetation.
• Spraying areas targeted for revegetation with lime and potash.
• Spraying targeted areas with a sludge-fly ash mixture.
• Applying a mixture of grass or tree seeds to the targeted area. If the tree seed will not
germinate, seedlings will be planted.
• Applying a mulch cover to protect the seeds and permit seed germination (Reference 2, page
14).
The cost to EPA for the above remedial action is minimal, provided it costs the municipalities less to
spray the sludge than current sludge-disposal methods (Reference 2, page 13). The full cost to
implement this remedial action has been estimated at $2,750 per acre. The total cost to revegetate the
2,000 acres is approximately $5,500,000 (in 1986 dollars) (Reference 4, page 7-20).
Cinder Bank Operable Unit
The interim remedial action for the Cinder Bank Operable Unit was selected in June 1988. The
remedial action presented in the ROD for the Cinder Bank Operable Unit consists of the following
activities:
• Contouring to stabilize the Cinder Bank slopes and areas targeted for revegetation
• Installing gas vents where necessary
9
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Palmerton Zinc
• Constructing surface-water channels to direct Blue Mountain water runoff away from the
Cinder Bank area
• Constructing a collection and treatment system for Cinder Bank runoff until it is revegetated
• Establishing a vegetative cover over Cinder Bank
• Performing long-term inspections, monitoring, and maintenance of the site (Reference 1, pages
25 and 26).
The estimated present worth cost for this remedial action will be in excess of $2,861,000; however,
the exact figure will not be known until an agreement is reached on the extent of remediation during
remedial design (Reference 1, Abstract, page 2).
CURRENT STATUS
According to the Acting Remedial Project Manager, RODs for the first two Operable Units have been
signed by the EPA Regional Administrator. Operable Unit 1 (Blue Mountain) has started the
construction phase (May 7, 1991). Operable Unit 2 (Cinder Bank) is currently in consent decree
negotiation with the Potentially Responsible Party. Operable Unit 3 is in the Remedial
Investigation/Feasibility Study stage. Operable Unit 4 will enter the Remedial
Investigation/Feasibility Study stage in the summer of 1991.
10
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Mining Waste NPL Site Summary Report
REFERENCES
I. Record of Decision for Palmerton Zinc Pile, Pennsylvania: Second Remedial Action; James M.
Self, Regional Administrator, EPA Region ifi; September 1988.
2. Record of Decision for Palmerton Zinc Pennsylvania: Interim Remedial Measure; James M. Seif,
Regional Administrator, EPA Region ifi; September 4, 1987.
3. Draft Remedial Investigation Report: The New Jersey Zinc Company, Palmerton, Pennsylvania;
J.F. Griffen, EPA; July 8, 1987
4. Palmerton Zinc Superftmd Site Blue Mountain Project; EPA Region ifi; April 1987.
5. Remedial Investigation Report: The New Jersey Zinc Company, Palmerton, Pennsylvania; EPA;
November 20, 1987.
11
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Palmerton Zinc
BIBUOGRAPHY
EPA Region ifi. Palmerton Zinc Superfund Site Blue Mountain Project. April 1987.
Griffen, J.F. (EPA). Draft Remedial Investigation Report: The New Jersey Zinc Company,
Palmerton, Pennsylvania. July 8, 1987.
Leet, Maria (SAIC). Personnel Communication Concerning Palmerton Zinc to Tony Koller, EPA
Region ifi. June 13, 1990.
Seif, James M. (Regional Administrator, EPA Region ifi). Record of Decision for Palmerton Zinc
Pennsylvania: Interim Remedial Measure. September 4, 1987.
Seif, James M. (Regional Administrator, EPA Region III). Record of Decision for Palmerton Zinc
Pile, Pennsylvania: Second Remedial Action. September 1988.
U.S. Public Health Service and Agency for Toxic Substances and Disease Registry. Preliminary
Health Assessment, Cleveland Mill Site, Silver City, New Mexico. May 9, 1990.
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Palmerton Zinc Mining Waste NPL Site Summary Report
Reference 1
Excerpts From Record of Decision for
Palmerton Zinc Pile, Pennsylvania: Second Remedial Action;
James M. Self, Regional Administrator, EPA Region ifi;
September, 1988
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United States
Environmental Pr tecon
Agency
OffIce of
Emergency and
Remeøiaj Response
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EPA
Superfund
Record of Decision:
Palmerton Zinc Pile, PA
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. .Id 3 tUS
ERFUND RECORD OF DECISION
.glmertofl Z,.nc, PA
corid Remedial Action
11. AbU.ct (L.e”it 200 . ssl
The Palmerton Zinc site is composed of two locations in the Borough of Palmertorl,
Carbon County, Pennsylvania. Smelting operations have been conducted at two locat ons,
a west smelter and art east smelter, flanking the Town of Palmerton, which is located at
the co .fluence of the Lehigh River and Aquashacola Creek. Approximately 7,000 residents
live in palmerton, many of whom work at the smelting facility. Land use in the area is
industrial, residential, and agricultural. The drainage pattern in the site area is
ward Aquashicola Creek, designated a warm water fishery by the State of Pennsylvania,
.iich flows into Lehigh River. Smelting operations were conducted in the west plant
from 1E98 to 1987, and in the east plant from 1911 to present. The site has had tnree
owners, including the current operator, Zinc Corporation of America, and historically
has prcduced zinc and other metals for a variety of products. Primary smelting of
concentrated zinc sulfide ores, conducted until December 1980, resulted in the e’tuSsiOn
of larce quantities of zinc, lead, cadmium, and sulfer dioxide. This air pollution
caused defoliation of over 2,000 acres of vegetation in the vicinity of the east
smelter. Between 1898 and 1987 process residue and other plant wastes (as well as
municipal waste until 1970) were disposed of on Cinder Bank, a 2.5—mile, 2,000-acre
waste pile located behind the east plant at the base of the Blue Mountains. Cinder Bank
(See Attached Sheet)
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palmerton Zinc, PA
Second Remedial Action
Contaminated Media: gw, sw, sediments
Key Contaminants: cadmium, lead, zinc
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EP A/ROD/R03—8 8/0 63
Palmerton Zinc, PA
Second Remedial Action
16. ABSTRACT (continued)
contains approximately 27.5 million tons of leachable metals including lead, zinc, and
cad iuuin, as well as carbonaceous material. Large blocks of residue crack and break off,
allowing rapid infiltration of runoff during periods of rain and snow melt resulting in
contaminated leachate percolating down to the ground water and seeping out of Cinder
Bank. This remedial action addresses Cinder Sank. Additional areas of contaminat ,cn as
well as ground water and surface water contamination will, be addressed in subsequent
remedial actions. The primary contaminants of concern affecting the sethrnents, ground
water, and surface water are metals including cadmium, lead and zinc.
The selected remedial action for this site includes: slope modification, cap ing, and
application of a vegetative cover on Cinder Bank; construction of surface water
diversion channels; surface water and leachate collection and trea.ine t using
lime-activated filtration lagoons and/or constructed wetlands; ,rnp1ementation of an
inspection, monitoring, and ma .ntenance plan; and wetlands resto-atjcr. r’ easures, if
necessary. The estimated present worth cost for this remedia. actiolL will be in excess
of $2,861,800; however, the exact figure will not be known uncil agree’rtent is reached on
the extent of remediation during remedial design.
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— S
?ametton Zinc Site
Operable Lt ti
Cinder Ban’c
:. troduction
The uperfund investigation of tne Palmerton Zinc smelter
focuses on four problem areas whicr are each being studied as
indi1idual unitS: first, the deposition of heavy teeals,
mainly oadmium, lead, and zinc, throughout the valley as a
result of air emissions from the smelter; second, the Cinder
3ank, approximatelY 2.5 miLes Long, which consists of an
estimated 33 milLion torts of slag; thitd, tne defoliated
orriort5 of alue Mountain next to the smelter; and fourth,
tne overall site groundwater and surface water contamination.
The investigation of the Cinder Bank, which is Located on t e
smelter roperty and at the base of Blue Mountain, iS the
subject discussed herein. The Blue Mountain unit has recent.y
entered the design phase, while the valley and g:oundwatet/SurfaC!
water units are in the Remedial tnvestigation and Feasibility
Study thase.
tt. Site Name, t.ocation and Description
The Palrnertor t Zinc Superfund Site is Located in the
Borough of Palmerton, Carbon County, Pennsylvania as shown
on Figure 1.. The town is situated at the confluence of the
t.ehigh River and Aquashicola Creek, just north of the r..ehigh
Water Gap. t.and uses in the area include industrial sites,
forest Lands, residential communities arid agricultural farm-
lands. Approximately 7,øø residents live withiri the town
whicn has historically provided a majority of the workforce
at tne smelter. From 1398 to 1967 the smelter was privately
owned by the now defunct New ,ersey Zinc Company. It was tnen
sold to Gulf & Western Inc. which operated the facility
until 1981, when it was purchased by its current owner Zinc
Corporation of America.
The topography surrounding the site is mountainous, lying
in a deep valley within the Appalachian Mountains between
aLue Mountain (elevation L,5ø feet) and Stony Ridge (elevation
900 feet) . The Appalachian Trail runs along the top of 3].ue
Mountain.
The smelting operations are Located at two separate
locations, a west smelter and an east smelter. Both smelters
are located at the base of Blue Mountairi (see Figure 2).
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The mayor watercourse in the project area is the Lehigh
River. The drainage pattern of the study area is toward
Aquashicola Creek, a tributary of the Lehigh River. Aquash-
icola Creek flows through a buried valley, between Blue
Mountain on the south and Stony Ridge on the north. The
creek flows southwesterly and is joined by Buckuha Creek
about one—half mile upstream of Harris Bridge and by Mill
Creek near the east plant’s main gate (See Figure 2). Aquash-
icola Creek flows into the Lehigh River approximately 1.5
miles southwest of the east plant.
The reach of Aquashicota Creek in Palmerton is classified
as a warm water fishery and is stocked for trout by the Perinsyl-
vania Department of Environmental Resources. According to
the criteria of water uses in this classification, the creek
should maintain stocked trout from February 15 to July 31.
It should also maintain and propagate fish species and addi-
tional flora and fauna that are indigenous to a warm—water
haoi tat.
A water intake is located on the Aquashicola Creek near
the Field Station Bridge. This intake pumps water from the
stream for industrial use at the east plant. Water from Aquash—
icola Creek is also pumped from an intake located between the
Main Gate Bridge and the Sixth Street Bridge during times of
emergency need for industrial process water.
Groundwater in the site vicinity occurs in both the
unconsolidated deposits and the underlying bedrock. The
shallow aquifer is classified as a Class 3 aquifer and the deep
aquifer is classified 2a as determined by EPA Groundwater
Classification Guidelines.
At the foot of Blue Mountain, the Palmer Water Company,
which supplies water to the towns of Palmerton and Aquashicola,
has as its water source four production wells, ranging in
depth from about 200 feet to more than 400 feet, drawing
ground water from bedrock. The yield of these wells reportedly
ranges from 115 to 130 gallons per. minute.
III. Site History
The Zinc Corporation of America currently operates one
zinc smelter in Palmerton, referred to as the east plant,
which opened for operation in £911. Another smelter located
in tne west plant had operated between 1898 and 1987 at which
time it was shut down. The Palmerton Zinc facility historica .
has produced zinc and other metals for machinery, pharmaceu-
ticals, pigments, and many other products.
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Primary smelting of concentrated zinc sulfide ores, wrijch
was tne main source of air pollution, was Stopoed in December
of 1980. However, until then the smelters had emmitted Large
quantities of zinc, lead, cadmium and sulfur dioxide which
caused to the defoliation of many acres of Land including
a oroximareLy 2,300 acres on Blue Mountain, located adjacent
to the east smelter. Aerial photography of the site taken
from L938 to 1985 shows the various stages of damage to
vegetation. Vegetation damage is defined as areas of exposed
rock and soil where the original vegetation, as seen on a
L 38 aerial phoegraph, has been destroyed as a result of the
smelter’s emissions.
Vegetation damage first appeared on a 1951 aerial photo—
:.aon as isolated patches on erie steep, north—facing slope of
3Lue Mountain, located immediately south of the Palmerton Zinc
: plane. uring erie 1938—1985 period of analysis, the
“egetation damage progressed and additional areas of damage
a? eared. By 1985, vegetation damage appeared as a continuous,
widespread area with barren, eroded land visible in aerial
photographs.
The disposal of plant waste since the smelter operations
began at Palmerton in 1898 has enabled the Cinder Bank t be
built to its present dimensions of 2.5 miles and 33 x
tons. It contains large amounts of Leachable lead, zinc,
cadmium, and other metals.
I v. Enforcement History
Past zinc smelting operations have created widespread
heavy metal contamination both on and off the Palmerton Zinc
plant property. The contaminated areas have been divided
nto four distinct areas by EPA and are referred to as the
Blue Mountain Project, the Cinder Bank, the Valley Contami-
nation and overall groundwater and surface water contam—
nation. An RI/I’S for the Cinder Bank has recently been corn-
pleted by the Zinc Corporation of America who, as the current
owner of the facility is a potentially responsible party
(PR?) at this site. The Valley Contamination Study is
currently being performed under a Consent Order by Gulf and
Western, the other PR? associated with this site. Both PRPs
declined participation in the Blue Mountain RI/! S which was
ornpLeeed by EPA in April, 1987.
En a Letter dated June 13, 1987, EPA gave the PRPs notice
.r f their potential Liacility with regard to the implementation
•f the Blue Mountain Project remedial action. Enclosed with
this letter was a copy of the completed RI/ES and a copy of
E’A’s proposed remedial, alternative. The PRPs were extended
ehe opportunity to present a good faith proposal to conduct
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the Remedial Action to tte Agency witniri sixty (60 ) days of
receipt of the June 1.0, 1987 notice letter. EPA received a
proposal from ZCA and completed successful negotiationS in
r ic ZCA, oy means of a Consent ecree agreed to implement
the Blue MoUntain ROD. Gulf and Western Inc. again declined
participatiofl in this rO)eCt.
V. Site Characteristics
4
A. eo1.ogy/HYdr0ge0l0gY
1. SURFACE WATER
The drainage pattern of the study area is towa: Aquash-
cola Creek, a tributary of the t.ehigh River. Aquashicola
C:eek flows through a buried valley, between Blue Mountain on
:ne soutn and Stony Ridge on the north. The creek flows
southwesterly and 13 joined by Buckuha Creek about one—half
niLe upst:aam of Harris Bridge and by Mill Creek near tne
east plant’s main gate. Aquashicola Creek flows into the
Leriigh River approximately 1.5 miles southwest of the zinc
plant.
The reach of Aquashicola Creek in PalmertOrl is classified
as a ro t stocking stream by the Pennsylvania Department of
nvironmenta1 Resources.
A water intake is located Ofl the Aquashicola Creek near
the Field Station Bridge. This intake pumps water from the
stream for industrial use at the east plant. ? 1 quashicola
Creek water is also pumped from an intake located between the
Main sate Bridge and the Sixth Street Bridge during times of
emergency need for industrial process water.
2. GROUND WATER
Groundwater in the site vicinity occurs in both the un—
consolidated deposits and the underlying bedrock. The glacial
outwash deposits in the stream valley contain significant
variabilitY typical of this type of deposit.
Bedrock in the site area also contains significant guan-
tities of groundwater. The intense deformation of the bedrock
is expected to occur through interconnected fractures and in
related solution openings in the limestone formations. The
degree of interconnection between the unconsolidated and bed-
rock aquifers and their relationship to nearby surface waters
has not been defined tO date, but is being investigated.
4’
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At the foot of Blue Mountain, the Palmer Water Company,
which supplies water to the towns of ?almerton and Aquashi—
cola, has as its water source four production wells, ranging
in depth from acout 200 feet to more than 400 feet, which
draw groundwater from the bedrock aquifer. The yield of these
wells reportedly ranges from 115 to 130 galLons per ninute.
The depth to groundwater in the valley is reported to
oe about 5 feet. The flow directions of shallow groundwater
are expected to be controlled by local topography and by
Aquashicola Creek. Shallow groundwater may flow north from
Blue Mountain to the creek. Wells installed in tne ur%conso l-
idared deposits near Aquashicola Creek may receive substantial
recharge from the creek. Deeper groundwater flow may be in-
fluenced pr marily by both structural and stratigraphic
relationsoips. Furthermore, deep groundwater will Likely flow
f: m ene site toward the Lehigh River, t the west-southwest.
The groundwater flow patterns are also being investigated.
3. Soils
.The bedrock of Blue Mountain is Silurian—aged Shawangunk
Conglomerate, ranging from a quartzitic sandstone to a coarse
conglomerate. To the south is the Ordovician Martinsburg
Shale, and, to the north, are red siltstones and sha].es inter-
bedded wirn limestone and sandstone in the Bloomsburg (Cayuga)
formation.
All of Carbon County was glaciated by the Kansan Clacier.
The second, or I llinoian, glacier extended into the valleys
to the north and south of Blue Mountain, but apparently did
not cover the ridge itself.
The periglacial frost action during the Illinoian and Wisconsin
glacial periods resulted in shallow channery soils on most
ridges with deep deposits of colluvial material at the bases.
B. Extent of Contamination
1. Cinder Bank
A. Nature of Cinder Bank Wastes
Much of the Cinder Bank residue is in the form of bri—
quettes from the vertical retorts and contains residual metals
and carbonaceous material. As a result of either incomplete
quenching or spontaneous combustion large portions smolder con—
tinously and several of these areas are posted as “Fire Areas.”
In areas that have not been physically disturbed, large crac s
form in the surface roughly parallel to the outer edge.
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Occasionally large blocks of partially consolidated residue
come off of the main nass of the Cinder Bank and tumble down
the steep north slope towards Aquashicola creek. As the
cracks develoc, steam and smoke issue from them leaving
sublimated yellowish deposits on the ad acent surfaces. These
cracks and resulting broken rough surfaces provide avenues
for rapid infiltration and percolation of rain and snow melt,
and facilitate Leaching of soluble constituents from tne
Cinder 3ank.
tn 1981. approximately 1,800 linear feet of reside in the
Palmerton cinder oank was sampled and analyzed. The pur ose
of tne project was to define as accurately as possible the
recoveraole values in this waste pile.
Twenty—seven holes were drilled by the New jersey Zinc
Company in a more or less random pattern into tne seven zones
hi:n comprise tne residue bank. If there was any bias in
select .ng the locations to be investigated, it was that the
drilling areas were onosen where the expectation of high
metallic values was greatest. Approximately 200 sampLes were
taken and analyzed.
The results of the drilling program, which analyzed for
s ecific metals, are summarized below and as a whole, the
bank can be said to contain the following:
27,500,000 Tons of Res.due
1.6% Carbon
2.7% Zinc
0.025% Cadmium
0.36% t.ead
0.33% Copper
0.6 Oz./T Indiim
The Cinder Bank has been the repository of process re-
sidues and other wastes from the Palmerton operations for the
past 65 years. It is located behind the Last Plant and stretches
approximately two and one—half miles along the base of Blue
Mountain, covering about 200 acres of the lower slope. Unt l
1970, all of Palmerton’s municipal waste was disposed by
burying it in the residue. As of Decemb.!r 1987 the Cinder
Bank ceased to be used as a depository for plant waste material.
n estimated 25—30 million tons of v.irious materials are
deposited over this area in irregular piles and ridges. Some
segregation by type has been practiced in recent years with
tne objective of potential reclamation. During the past 30
years, considerable guantities of material suitable for aggreg-
ate and anti—skid uses have been removed by private contractors.
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B. Cinder Bank Runoff and Seepage
Much of the Cinder 9ank residue is in the form of briquettes
prom the vertical retorts and contains residual metals and
carbonaceouS material. As a result of either incomplete
quenching or spontaneous combustion large portions smolder
continuously and several of these areas are posted as “Fire
Areas”. In areas that have riot been physically disturbed,
large cracks form in the surface roughly parallel to the
outer edge. Occasionally large blocks of partially corisol—
idated residue come off of the main mass of the Cinder Bank
arid tumble down the steep north slope toward Aquashicola
Creek. As the cracks develop, steam and smoke issue from
them leaving sublimated sulfurous deposits on the adjacent
surfaces. These cracks and resulting broken rough surfaces
provide avenues for rapid infiltration and percolation of
rain arid snow melt arid facilitate leaching of soluble con—
st tue ts from the Cinder Bank. In addition, the Cinder Bank
has been contoured to a slope approaching 2 to I which is
unstable.
Evidence of cuinera•L leachate from the Cinder Bank is abun-
dant. Zinc concentrations in waters passing over or through
trie Cinder Bank increased significantly, especially in the
area east of NEIC Station 69 (NJZ Station 1ØA) (see Figure
4) . In this area, zinc concentrations increased from back-
ground levels ranging from .27 to v.67 mg/i to values genera’_Ly
greater than 17 mg/i arid as high as 23 mg/i in Cicider Bank
run—off and seepage. Increase cadmium concentrations in trie
Cinder Bank run—off were also highest in this area.
The high concentrations of zinc in run—off arid seepage
from the east end of the Cinder Bank contributes to significant
increases of zinc in Aquashicola Creek. About one—half of trie
total zinc load to the creek entered upstream of the Field
Station Bridge (see Figure 2).
Cadmium arid zinc were detected in all samples from seeps
arid springs near the base of the Cinder 3ank. The average
concentration of dissolved cadmium in samples from the seeps
arid springs at the base of the Cinder Bank was .ll3 mg/i or
aoout l times higher than the run—off not influenced by the
Cinder Bank. The average of all dissolved zinc concentrations
in samples of seeps arid springs at the base of the Cinder
Bank was 35 mg/i or about 24 times greater than background.
The highest concentrations of cadmium and zinc observed
were in samples from seeps and springs along the eastern .6
mile at the base of the Cinder Bank. These samples
also exhibited low pH values from 4.3 to about 6 standard
units.
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Data from samp].es of seeps and springs at the base of
the Cinder Bank show clearly that cadmium and zinc are being
leached from the Cinder Bank and contrioute to the contamin-
ation of Aquasnicola Creek and the area groundwater.
Average annual precipitation in ene vicinity of PaL erton
LS anout 46 in. (117 cn ) of which acout 49% falls during the
growing season (May to September) ; average annual runoff is
aoout 24 in. (61 cm) . The drainage area directly anove quash-
icola Creek to the crest of Blue Mountain in tne reach sDanned
by ene Z cast Plant and the Cinder Bank is aoout 1,100 acres
(4.5 x L sq m) . Therefore tne average annual run—off to
Aquashicola Creek from the Cinder Bank and Blue Mountain is
about 2,20 acre—ft. Assuming tnat run—off and seepage flows
and metals concentrations during the surveys were represent-
ative of average conditions, the average annual loads of
cadmium and zinc cont iouted to Aquasnicola Creek in the
reach oetween tne ease end of the Cinder Bank and the 6th
Street Bridge would be estimated at anout 0.48 tons/yr and
110 tons/YE, respectively.
During periods of run—off, contaminated storm water 3er-
colates through tne Cinder Bank to the groundwater. The
groundwater recharges the creek and also seeps out through
the Cinder Bank. The Company has attempted to isolate Blue
Mountain runoff from the Cinder Bank with little success.
Pipes were placed at the surface discharges of two rills to
convey this water over the Cinder Bank. The pipes on top of
the Cinder Bank froze, split and were not repaired. As a
result, the water flows into the Cinder Bank.
2. Surface Water
There are significant contributions of zinc, cadmium and
manganese to Aquashicola Creek in the reach from Harris Bridge
to the 6th Street Bridge, located just downstream from the
East Plant. Zinc and cadmium loads each increased about thirty
times in this reach, while manganese increased sevenfold. No
increases in metals above that which was found in the reach of
the Aquashicola Creek from the Harris Bridge to the 6th Street
Bridge were noted between the 6th Street Bridge and the Tatra
Inn Bridge at the confluence of Aquashicola Creek and the t.ehigri
River.
1
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Based on five—day average data, most of the zinc and cadmium
.oad was contributed to Aguashicola Creek by groundwater and
run—off sources:
Source Zinc Cadmiun
Non—point contribution
between Harris and Field
Station Bridges (5) 50
Non—point contribution between
Field Station and 6th Street
Bridges (5) 32 79
Total of non—point contribution
between Harris and 6th Se.
Bridges (5) 82 92
!ast Plant Discharges (5) 18 8
Total (5) 100 100
Most of the zinc enters the creek upstream of the Field S:aeion
Bridge. However, most of the cadmium enters the creek be:ween
tne Field Station and 6th Street Bridges in the reach directly
adjacent to the plant.
Cross—sectional concentration data at three stations in t e
Harris Bridge to 6th Street Bridge reach showed generally
higher zinc and cadmium levels on the Cinder Bank side of the
creek. No significant metal concentrations were found in
Mill Creek, indicating that the run—off and groundwater from
the drainage area on the left side of Aquashicola Creek are
relatively metal—free.
Particulate erosion from the Cinder Bank adds to the contamin-
ation of Aquashicola Creek. Sediment analyses for cadrniw’t,
zinc, manganese, lead, and copper from Aquashicola Creek stations
adjacent to the Cinder Bank showed increases above nearby back-
ground stations of 32, 26, 17, Il, and 10 times, respecti;’ ly.
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Metals released to Aquashicola Creek in the reach adja-
cent to the Cinder Bank had a negative impact on water quality,
resulting in imbalanced aquatic communities. Benthic macro—
inverteorare and periphyton numbers and diversity were reduced,
as was the survival, of test fish.
3. Sediment Quality
Zinc concentrations in sediments from the background
Stations (27, 99 and 30) ranged from 420 mg/g to 840 rng/g and
averaged 620 mg/g. The stations (25, 24, 23, 22, 21, and 20)
adjacent to the Cinder Bank, East Plant and downstream on
Aquashicola Creek to its confluence with the t..ehigh River
ranged from 6,200 mg/g to 42,000 mg/g and averaged 19,900 mg/g.
This is 32 times the average of the bac cground stations.
Cadmium concentrations in sediments from the background
stations ranged from 2 to 13 mg/I and averaged 6 mg/i. The
Stations (25, 24, 23, 22, 21, and 20) adjacent to the Cinder
Bank, East Plant and downstream on Aquashicola Creek to its
confluence with the t.ehigh River ranged from 39 mg/i to 420
mg/i and averaged 1,57 mg/g. This is 26 times the average of
the background stations.
Similarly, manganese, lead, and copper, as compared to
the background stations, showed corresponding increases adjacent
to the Cinder Bank and East Plant areas of 17%, 11% and 1.0%,
respectively.
Background concentrations of zinc in stream sediments in
soutneasteen Pennsylvania are generally less than 200 parts
per million (ppm). The high concentrations of metals in
Aquashicola Creek and in the t.ehigh River sediment are attri-
buted to discharges including erosion from the Cinder Bank.
A. Benthic Macroinvertebrates
Both Aquashicola Creek and the t.ehigh River are character-
ized by a well—entrenched channel, moderate gradient and fre-
quent large cobble—filled riffles over a hard—rock bottom.
Thoughout the study area, including reference (control) sites,
benthiç ruacroinvertebrate population levels ware low (44 to
1851/m’) indicating that both Aquashicola Creek and the r.ehigh
River are not highly productive.
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tn Aquashicola Creek at Station 27, the reference station,
the benthos reflected good water quality. The 29 kinds of orga—
ri’.sms collected were well i.stributed among the. forms present.
Conditions oegan to deter orate at the next two downstream sites,
stations 32 and 25, unere a 43% reducti n in the rtumoer
of kinds and 45% reduction in numbers/mh occurred. This reach
of the stream is influenced by run—off from the N. Z Cinder 3ank
and changes in the benthos population are attributed to the
high heavy metal concentrations in the run—off.
Conditions found in the r ehigh River, both upstream and
downstream of Aquashicola Creek, reflect typical conditions
f r large, organically enriched, eastern U.S. rivers. No
aooarent effect of Aquashicola Creek on the river was ooserved.
B. Periphyton
Periphyton communities reflected the influence of the Palm—
erton Zinc Site in several ways. Attached algal populations
responded to the toxicity of Cinder Bank run—gff and seepage by
decreasing from about 40,000 organisms er cm 4 at reference
Station 27 to about 23,300 and 5,003/cm’ in the reach ad3acent
to the Cinder Bank. This toxicity—induced decrease was also
re ected in low chlorophyll concentrations of 69 and 27 ug/
It appears that wastes carried by Aquashicola Creek did
not influence L,ehigh River periphyton significantly; communities
were similar in numbers and composition upstream and downstream
from the creek confluence.
C. Fish Survival
Mortalities among in—situ test fish occurred at six of eleven
exposure sites. Significant mortality (greater than the 12%
allowable for the control group) only occurred at Stations
22, 21, 22, and 23; this is the reach of Aquashicola Creek
extendirig from the mouth to approximately 3 river kilometers
upstream. This stretch of the creek receives Cinder Bank
run—off and seepage.
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There appears to be a correlation between total zinc
concentration and mortality. P 1 t Station 24, the average
total zinc concentration during the exposure period was 0.49
mg/i and no mortality of test fish was recorded. Station 21
had an average total zinc concentration of 0.87mg/i, and
produced the highest mortality of any site (40%) . At Station
20, near the confluence of Aquashico] .a Creek, total zinc concen-
tration was somewhat lower at 0.71 mg/i and 20% mortality
occurred.
3. Groundwater Quality
Specific conductivity of groundwater samples from seven
wells on tne East Plant site ranged from 130 to 800 micromhos
per centimeter. Calculated total dissolved solids concentrations
ranged from 85 mg/I to 520 mg/l. Generally, waters of this
quality are considered acceptable for public drin ing water
supply. Mowever, zinc concentrations in groundwater ranged
from 0.003 mg/i to 3.2 mg/i and cadmium concentrations ranged
from 0.002 mg/i to 0.024 mg/I. Zinc was detected in all
seven wells sampled and cadmium was detected in four of the
seven wells sampled. Higher levels of zinc and cadmium were
detected in the two wells designated as Stations 93 and 94.
These wells are located on the east side of the field Station
between the Cinder Bank and raw materials storage area on the
south and Aquashicola Creek on the north. Because of its
location and the presumed direction of natural groundwater
flow from south (Blue Mountain) to north (Aquashicola Creek)
it is likely that the high metals concentrations in the wells
resulted from leachate originating in the Cinder Bank.
Pumping of the wells in this well field induces groundwater flow
toward the well field from the Creek. The dilution of the
groundwater provided by this infiltration results in metals con-
centrations somewhat lower than would be expected in the shallow
aquifer if no pumping and induced infiltration were occurring.
Station Nos. 96, 97 and 98 are wells at the west end of
the -East Plant area on the lower flank of Blue Mountain near
the Palmer Water Company maintenan.ce building and a railroad
switching yard. These wells are referred to by the Palmer
water Company as deep wells,N ranging in depth from about
200 ft (6 m) to more than 400 ft (120 in) . The aquifers
tapped by these wells are bedrock aquifers of small yield and
have little or no direct contact with surface waters or the
shallow alluvial aquifer. A small amount of cadmium was
detected in Station No. 98 and low concentrations of zinc
were detected in each of these three wells.
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C. SUMMARY 0 ! SITE RISKS
As required by the Superfund Amendments and Reauthori-
zation Act (SARA) of 1986, PA asked the U.S. Public Health
Service, Agency for Toxic Substances and Disease Registry
(.;TSDR) to evaluate the health threat posed by the defoliated
por:ioris of alue Mountain. In a February 6, 1987 memorandum,
ATSDR found that there is potential risk in human exposure
through consumption of fish.
£rosiot, and run—off from the Cinder Bank have contributed
to high metal levels in fish. The levels of lead and cadmium
in tne fish present a potentially significant health threat
t persons who regularly consume fish from area streams. It
is ATSDR’s opinion that “. . . consumption of fish from the
area streams presents a potential health threat and . . . trie
public should be advised to consume fish from the immediate
area streams on a Limited basis only (rio more than once per
week) .“
Rainwater infiltration and surface water infiltration
(Blue Mountain runoff) are leaching metals from the Cinder
Bank and contributing to contamination of Aquashicola Creek.
t.ow pH values assist in the leaching of metals from certain
sections of the Cinder Bank.
The easternmost portion of the Cinder Bank appears to have
the greatest impact on water quality with the zinc concentra-
tions averaging 40 to 80 times greater than background zinc
conc3r itrations and cadmium concentrating averaging 12 times
grea:er than background cadmium concentrations.
If average metal concentrations obtained from ZCA’S two—
sampUng events in 1996 are assumed for the entire Cinder Bank,
tnen these values, along with run—off and drainage area calcu-
lations from NEIC’s 1979 investigation, indicate that the
Cinder Bank may contribute 283 lbs. of cadmium, 622
Lbs. of copper, 90 lbs. of lead, 296 Lbs. of manganese, and
117,351 lbs. of zinc to Aquashicola Creek each year.
1on—point sources, such as groundwater discharge, are re-
sponsible for between 80 and 95 percent of metals loading to
Aqua ;hicola Creek.
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VI. Community Relations History
The community has generally been concerned about the
environmental devastation and the negative image a barren
mountain pro ects. The action being considered at this time
deals only with the Cinder Bank, however, there are two other
rna or contamination proolems which are of public concern: 1.)
widespread soil contamination which exists because of the
deposition of heavy metals from past air emissions from the
smelter, and 2) significant groundwater and surface water
contamination on and near the smelter property.
The public has been concerned about the potential health
effects of the soil and groundwater contamination and also
about the potential financial impact on the Zinc Corporation
of America of any remedial action. An Rt/F5 on the widespread
soil. contamination is being completed by the previous owners
of the smelter, Gulf & Western, Inc. pursuant to a consent
order with EPA. The report will be available for public
review and comment in he coming months. A separate RI/!S
for the overall surface water and groundwater is also underway.
VII. Remedial Alternative Objectives
The major ob ectives of remedial actions to be taken at the
Palmerto Zinc Superfund Site include (1) minimize direct con-
tact witn the Cinder Bank (2) reduce volume of run—off, (3)
reduce contamination in run—off, (4) reduce the volume of run—
on, (5) collect and treat leachate, (6) reduce wind—borne
contaminated emissions and (7) reduce particulate erosion.
Based on the above ob ectives, numerous source control
and mitigation control technologies were screened to provide
a limited number of technologies applicable for remedial
actions at the Site. Some of these technologies were removed
from further consideration based on site specific information
and other comparative criteria listed in Table 1.
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guidelines require that soil. pH be adjusted to 6.3 in the
first year, up to pH 6.5 by the second year and maintained at
6.5 for 2 years fo].lowirig application. With joint applicationS
of lime and fly ash, these levels should be attainable. ?
rorective erosion and sedimentation plan will be developed
arid implemented.
It nay be technically impossible to meet some of the guide-
Lines (i.e. sludge application and 2 foot municipal landfill soil
cover) because of the terrain on the Cinder Bank. Specifically,
tne steep terrain prevents incorporation of the sludge/fly
ash into some areas of the cinders as preferred by the guide-
lines; the slopes of the Cinder Bank are in excess of the 23%
axi:Ttun recommended by trie guidelines. To overcome these
roolemnS, the project can be implemented tO minimize any
erosion caused by the steep slopes and the inability tO incor-
porate the sludge. Consideration of Wetland and Floodplain
Regulations will be incorporated irito the final plans when
making decisions on slope contours.
Overland movement of the sludge/fly ash mixture was
nonexistent during the field tests. The long term effective-
ness of the alternative can be monitored through soil arid
water sampling. Veg?tattve growth and metals uptake by the
plants can also be e.isily monitored.
O e:ation arid m.ainteflarice will be necessary to control erosion
of the soil amendments arid insure the integrity of the vegetative
cover. Because the pH of the rainfall in Palmerton is acidic,
t is anticipated that over several years the Site could
begin to reacidify. This can be easily monitored through
routine soil testing and top_dressings of lime can be applied
as needed.
A1l remedial action on surface water arid groundwater beyond
controlling Cinderbank Run—on and run—off will be handled under
Palmertorl Zinc Operable Unit 4.
- The costs to im,lement this alternative are calculated
to be approximately 4,5ØØ,3øø which includes some slope contouring
and placement of 2 foot soil cover on 25% of the Cirideroank (this
percentage is for costing purposes only)
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— h .. —
Alternative 3 - Collection arid Treatment of Runoff and Run—on
This alternative would consist of using a combination of
Lime activated filtration lagoons arid/or constructed wetlands
as a treatment for the collected run—off. These systems should
precipitate or bioac:umulate any metals that remain in the run-
off. t..aboratory tests and field studies have demonstrated that
oth of these technologies are technically feasible. The exact
design and procedures will be based on further laboratory arid
field tests.
This alternative will, be effective in both the short—term
arid the long—term for the lime filtration lagoons, and in the
Long—term for the constructed wetlands, following the estab-
lishment of the vegetation. This alternative will reduce the
toxicity and cnooility of the the hazardous substances on site.
This alternative meets all seven of the remedial action ob—
ectives. In addition, it meets the Clean Water Act requirements
of BMP to reduce surface water discharges.
The vegetation in the wetlands will reduce the toxicity,
mobility and volume of metals in the run—off by bioaccumulation.
As the vegetation in the wetlands becomes saturated with metals,
it can be harvested and run through the kiln.
The Lime in the filtration lagoons will reduce the toxicity,
mobility and volume of metals in the water being treated by chem—
‘.cal precipitation of the metals. As the lime becomes saturated
with metals, it can be replaced with fresh Lime, and the old
material can be run through the kiln and regenerated. The short-
term technical and administrative feasibility is very good. It
is technically feasible to install constructed wetlands and
lime—activated filtration lagoons. The materials and equipment
needed are available or could be purchased. The cost of this
alternative is approximately $2,861,800.
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The Long—term effectiveness of this alternative can be
monitored through water, plant, and soil samp].ing. Operation
and maintenance should be Li:nited to harvest of the aoove—
ground portionS of the wetland plants on an infrequent basis
and replenishment of the lime in the filtration lagoons as
needed. Some routine maintenance such as keeping water dis-
persion structures operational will be needed periodically.
The goal of this alternative is to treat Cinder Bank Leacn—
ate and potentially treat Blue tountain run—off and reduce
metal levels to surface water background comparable to areas
not impacted by the Palmerton Zinc Site.
AlternatiVe 4— Capping Using Soil and Vegetation
This alternative would consist of contouring the Cinder
Bank and applying a cap on the Cinder Bank. This cap would
prevent water from infiltrating the cinders and will consist
of an initial placement of 6 inches of soil, and bentonite
mixture covered by 18” of soil. Over the cap, there will be
a cover of soil into which there may be incorporated wastewater
treatment sludge, lime potash, and fly—ash, or some combination
of these materials, to aid in establishing a vegetative cover
of shortrooted grasses for erosion control.
The alternative will meet remedial action ob)ectives.
The toxicity and mobility of the hazardous substances will be
reduced, although, because no cinders will actually be removed
from the Cinder Bank, the volume of hazardous substances at
the site will not be reduced.
The remedy is protective of human health and the environ-
merit, as it will eliminate access to the hazardous substances
by direct contact, prevent water and wind from movtng the
hazardous substances, and, ultimately, will, reduce metal—
contaminated water from entering either groundwater or surface
water.
Finally, the remedy satisfies the statutory preferences
for maximum use of alternative technology and for permanence.
While the remedy is innovative and practical, it is not
experimental, but rather comes from a proven method for
dealing with large piles of waste materials. The method’s
dependability also insures that it will permanently work to
eliminate access to the hazardous substances by water, wind,
animals, and humans. The cost of this alternative, assuming
contouring 25% of the Cinder Bank to a 30% grade, then placing
the cap on 50% of the Cinder Bank, is approximately $5,500, 0
(listed percentage for slope contour and cap placement are for
costing purposes only) . Operation arid maintenance costs arid
technical considerations
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• Documentation of Significant Chances
No significant changes to the preferred alternative pre-
sented in the proposed plan have occurred with the exceotion
of being more specific in addressing the required ARAR base covers
prior to the placement of the sludge—flyash mixture and vegetae:cri.
xrI. Selected emedial Alternative
A. Descriotion and Perfor tance Coals
Section 12]. of SARA and the current version of the National
Contingency Plan (NCP) (50 Fed. Reg. 47912, November 20, l9 5)
establish a variety of requirements pertaining to remedial
actions under CERCLA. Applying the current evaluation c:iter a
in Table 1 to the four remaining remedial Alternatives, we
recommend that Alternative 3 be implemented. tn addition,
on areas of the Cinder Bank which contain RCRA listed waste
Alternative 4 is recommended, otherwise, in the areas not contain’.nc
RCRA listed waste, Alternative 2 will be implemented. Prior to
implementation of any remediation alternatives, both EPA and PADER
will be in comolete agreement with the remedial design for the remedi
This is an interim remedy for the site. When the RI/I’S
for the other Operable Units are eom leted by the responsible
parties, RODS will be issued to address all aspects of the
site. This interim remedy will not, however, be inconsistent
with a final comprehensive remedy for the Site. This interim
remedy attempts to ensure compliance with all ARARS for this
Operable Unit and will be consistent, to the extent practicable,
with those ARARS addressed herein.
The general procedures for the above described remediat on
will be as follows:
Step ].: Contour S1o es of Cinder Bank
Slope modification is required to enhance pre-
cipitation run—off from the Cinder Bank and reduce
the amount of precipitation infiltration and
particulate erosion. Heavy equipment will be used
- to modify slopes targeted for vegetation. Excessively
steep or otherwise unstable slopes may be built—up
from the toe of the slope. Gas vents will be installed,
if necessary. The Remedial Design generated prior
to the implementation of this interim remedial action
will provide grading specifications necessary to
ensure success in the final cap placement.
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Ste 2: Construction of Surface Water Diversion Channels
Surface water diversion channels will be constructed,
which will assure the water run—off from Blue Mountain
will be diverted away from the Cinder Bank area.
During construction of the remediation action,
surface water run—off from Blue Mountain will be diverte
througn channels away from the Cinder Bank and to a
treatment system if warranted. t. eachate from the Cinder
Bank will be collected by channels and diverted to tne
treat.nent system. Initially, lagoons in compliance
with RCRA standards, will be utilized for the temporary
storage of collected surface water.
Step 3: Ccnstruct on and Cao
A cap consisting of a minimum of 18 ” of soils and 6”
of clay or soi]./beritonite mixture will be placed over
tne Cinder Bank
to prevent: 1) leachirig.of heavy metals
into the groundwater; and 2) seeps contaminated
with heavy metals from exiting the toe of the Cinder
Bank. ( See Alternative selection for further discussicri.)_
Step 4: Vegetative Cover
A stabilizing vegetative cover will be applied over
the cap. The cover may be comprised of a wastewater
treatment sludge/flyash mixture, or conventional
mulching, fertilization and seeding. The purpose of
the vegetative cover will be to stabilize the slopes,
prevent erosion, and control surface water movement.
Step 5: Long—Term Activities
An inspection, monitorin.g, and maintenance plan to
assure effectiveness of the remedy will be implemented.
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Palmerton Zinc Mining Waste NPL Site Summary Report
Reference 2
Excerpts From Record of Decision for
Palmerton Zinc Pennsylvania: Interim Remedial Measure;
James M. Self, Regional Administrator, EPA Region ifi;
September 4, 1987
0
-------
L fl1tOø LOS
Environmernai Prote on
Agency
Qthce of
Emergency and
Remed a Responaa
EPNRCO.RO3-.37,Q
Se iember 1987
EPA
Supertund
Record of Decision:
Palmer-ton Zinc,
PA
4
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TECHNICAL REPORT DATA
(Please read Thz:ri 4 cr:o,,: 0” ffie PCYCPTS before com, ler,n j
j Epo r NO 2
£?V OD/R03—87/036
3 c ’sErir S ACCE5$ QN o
41’ITLE ANO SuSTI1 .6
S ?ERF ND RECORD OF DECISIO ’I
?almerton Zinc, PA
r L- medjal Measu..e
S *E OMT QATE —
Seote ber 4, 192
6 PE FO SNGO GANIZATIONCOOE —
7 AUT$OM(SI
8 •Ep Oqup ORGANIZATI OF.l REPO r
9 PEMFOMMING OAl.dIZATIQr NAME ANO AOORE5$ —
10 •MOGRAM ELEMENT NO
II CONfRACT G ANTNO
‘2 SPONSORING AGENCY NAME ANO LOORESS —
J.S. Environmental Protection Agency
431 M Street, S. .
.
Washington, D.C. 20460
13 TYPE OF EPOR1 ANO PERIOD COVE
Final ROD Reoort
14 SPONSORING AGENCY CODE
800/00
15 SUPPLEMENTARY NOTES
15 A9 1MA T
The Palmerton Zinc site iS located in Caroon County, Pennsylvania. The New Jersey
Zinc Company currently operates two zinc smeltors in Palmerton at the base of Blue
‘ountain. These two smeltors are referred to as the ease and west plants. Since 1998,
t-e N w Jersey Zinc facility has roduced zinc and other metals for macninery,
pharmaceuticals, pioments and nany other products. Pri—ary smelting of concentrated
zinc sulfide ores which was terminated in December 1980, is the main source of
oollution. Prior to December 1980, the smeleors emitte: iuge quantities of zinc, lead,
cadrium and sulfer dioxide nicn led to the defoliation of approximately 2,000 acres or.
31.ie Mountain, adjacent to tre east sr eltor. Vegetatio- damage first apmeared on a ?5
aerial p oroora n as isoLated patcnes on the steco, nor:-’—facj.ng slope of Blue ourtain
located immediately soutr. of tr.e east plant. By 1985, vegetation damage progressed ole:
a continuous icesoread area leaving oarren, eroded land visi 1e. The primary
contaminants of concern leading to the defoliation of 31e Mountain include: Zinc,
lad, cadmium and sulfur dioxide.
T e selected interim remedial rneasure focuses on the estaolisnment of a natural
eastern forest ecosystem and includes: onsite installation of a concrete pad with ber—
to nix offs te sewage sludge and fly ash; construction of access roads; application of
lime (10 tons per acre) and potasn (80 pounds actual potassium per acre) on areas
(See trach d Sheet)
17 KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPToRS
b IOENT’FIERS,OPEN ENOED TERMS
C COSATI F:et Group
?ecord of Decision
Palmereon Zinc, PA
interim Re’iecial Measure
Contaminated : ‘ed a: woods, soil, sw
Key contaminants: zinc, leac, C3C iu ,
sulfur dioxide, Lnorganics, -ea;i eeals
15.OISTMIUUTION STATEMENT
19 SECURITY CLASS ‘TJiisR po ,,,
one
21 NO QP ‘AGES
34
20 SEC ...RIT’r C...iSS page, 22 ‘QICE
EPA Ps * 2220—1- (R... 4—771
••L Cu$ (3 ? 0 I 1
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E?A/ROD/RO 3—87/036
Palmerton Zinc, PA
Inter 1 Remedial Action
16. ABSTRACT (continued)
carceted for reVegeta’iOr. applLc3tion of fly ash a d offsite sludge on
target areas: a 1i:a: cn of ra s seed or seedlir.;s onto target areas; and
application of lc to proteCt r e The nunicipalities tnat i ay a ply
t e sewage sludge and orer a ertc entS sould do so at no cost to E?k,
tovided tne cost of i 1e e i t e alternative iS less tnan it costs t e
nunicipalitie s to diSpoSC f t e sLud. e. A ninial capital cost nay oc
develOped pe’ ding : e outco’e of n_c ;alLtY i pie’rentatiOfl iS5UCS. O&
will not oe recuirad.
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‘1
Thc or watercourse in the project area is the Lehigh River.
Th€ drainage pattern of the study area is t ard uashico1a Cre sç, a
tributdry of tne Ler i.gh River. Aquastucola Creek fl is through a
u_ried valley, between Blue ttuuntain on the south and Stony R.idge on
the rtorth. The creek fl s scuthwesteriy and is join by Buckwha
Creek ac o.at one—half mile upstream of Harris Bridge and by Mill Creek
near the east j lant’s main gate. ?4uashi.cola Creek fl s into the
Lehigh River approximately 1.S r iles soutflwest of the zinc plant.
The ream of Aquashico].a Creek in Palrt rton is classified as a
trout-stocking stream by the nnsy1vania part ent of Environn ntai.
Resources. According to the criteria of water uses in this classifica-
tion, the creek should maintain stocked trout fran Febtuary 15 to
July 31. It should also maintain and prcp ate fish species and
adoitional flora and fauna that are indigenous to a warm-water habitat.
A water intake is located on the Aquashicoja Creek near the Field
Stone Brioge. This intake puiips water fran the stream for industrial
use at the east plant. Aquashicola Creek water is also p1 rped fran
an intake located between the Main C te Bridge and the Sixth Street
Bridge during tu es of emergency neeo for industrial process water.
Ground water in the site vicinity occurs in both the unconsolidated
cepos its arc the urcerlyi.ng bedrock • The glacial a.ztwash deposits in
the stream valley contain significant quantities of available ground
water, as is typical of this type of deposit.
At the foot of Blue tiountain, the Palmar Water Caiçany, which
supplies water to the t rns of Palr rtcn and Aquashicola, has as its
water source four production wells, ranging in depth fran about 200
feet to r cre than 4 )0 feet, drawing ground water fran bedrock • The
yield of these wells reportedly ranges fran 115 to 130 gallons per
rnir .ite.
Site History
The New Jersey Zinc Ca any currently erates o zinc s eLters
in Palnerton, referenced to as the east and west plants, re ective1y.
The west lter began erations in 1898, arid in 1911, the east plant
opened for eration. The New Jersey Zinc facility has produced zinc
arc other tals for math inezy, p arm ceutieals, pi nts, arid many
other products.
Primary s ltirç of concentrated zinc sulfide ores, which is the
main source of pollution, was stcpped in I cember of 1980. Hau ver,
up until then the smalters had emitted huge quantities of zinc, lead,
c ni.um arid sulfur dioxide which has led to the defoliation of
approxirat.ely 2,0 0 acres on Blue 1’ intain whith is located adjacent
to the east sn lter. Mrial phor. rapr y of the site taken fran 193U
to 19 .5 has st n the various st es of vegetation iam ge. Vegetation
damage is defined as areas of e çosed rock and soil where the original
vegetation, as seen on a l53 aerial phov. raph, has probably been
stroyed as a result of the s lter emissions.
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egetac .c. n c.anac e tirst a carcd on a l D1 aerial. pnotogra ,n .s
so1at ci pat es on tne st cp nortrt—facir g slc e of Blue Mountain,
LC3tLCj ir eciately South o t i Pairerton Zinc smelter’s east ?lant.
the perioo of analysis, the ve Ctatiort uaxnage progressed and
acc.it.cnal areas of uai ge appeared. y 19 , vegetation carage dopearec
c er a C r tinuous WL(..espreaa area with barren, erodea lsnd visi Ie from
a r ai phct3grapr.s.
Current Site Statt.s
Surface soils s les were collected fran the defoliated port .ons
of Blue t ountain. Five sar le sites fran aiffererit locations of e
r cuntain were selected ancJ analyzec for the metals of concern. Recorced
levels of c r iur ranged f ran a high of 1,3 O ppet to a L of 364 porn, Lead
fran fran ,475 p n to p , and zinc fran 35,OUCI p n to l3,Q( .,
The naxi nisn Levels are up to 2, 600 tires the typical regional backgrcw c
levels for cadniurn, over 2,0C 3 tires the regional backgrour levels for Lead,
ano over 40u tires the regional background levels for zinc. pth profiles
st iea that rcst of the metal cont nj.nation is contained within the t o t
l i irt ies of soil. This is because the metals are .ind in organic r ter.aLs
wtuai prevent significant da’inwarc roverent of metals.
Uater fl ing acrces the defoliated portions of Blue Mountain has
er d the surface anc becae contarninatec with metals contained in
tue soil. The runoff and erce ion has carried the metal laciened soil
into ?çuastucoja Creek.
The runoff has been s led twice in recent years. In May of 1979,
EPA sastpled tne runoff as part of a cceprehensive study of the sr elter.
Ln t tara of l9o6, Horsetiead Industries s i 1ed the runoff ur er a
Supertund consent reement with EPA. The level.s obtaix re coopared
to EPA’s aient water-çua.Uty criteria. At aJ. st every sa lir
Location, the criteria was exceeded; in sate instances, the Levels re
20 tires higher than the criteria. The results of the sazçlir effort
b.ertorred in 1986 by brsehead Inó&stries is presented in Table 1.
A 19 4 study by the U.S. Fish and wildlife Service fa.ind very hign
metal ccncentratia in fish taken fran stream in the area. A.Lthcugh
tue rna or source of the metal cont ni.nating the creek cc s fran the
smelter prc erty, the rur tf fran the o ntain contrth tes to the
contanination and, in turn, to high metal Levels in tue fish. Figure 3
is a s Mry of all fi.sh-saxrplir results.
The envira’t entai Lr acts of the metal cont nination on the affected
area of Blue tlountain are obvious to the naked eye. Besides the defoliated
vegetation and erce ion, a noticeable absence of m icroflora, lichens,
arthr ods and wildlife species has occ.irred. Researchers have studied
this area extensively and have concluded that due to the u çact on
a wide variety of organisre in the ecosystem, a co rthensive picture
of the effects of poorly controlled metal emissions urges.
k
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gu elirias also rcç u.re soil. ph ac ;usteo to 6. ., in t f.rst
year, up to u.5 h by e seconc jear anc rr intair at for 2 years
af:er application. itn JOL t applicat oc of Li estonc an fly asn
evels shou1 be attainacle. A protectLve erosion an sec.L r tati:r.
ttrc plan will be ceveicpec anc lerrenc .
tt is tea rtical1 Lr pract ca1 to r eet sa e ot the guidelir.es because
of r. e terrain n Blue Iour1ta].n. Specifically, the rocky terrain prevents
incor oraticn of the sluc;e into the soil as preferrec by the guic.eii.r.es;
tne ic es of tfle trcuntai.n re in excess of the 20 percent naxi t r recccrrerce,
oy the guidelines; ano, there are becrock Q. tcrcçs on the r ntain that
tr e guidelines rec rrend be avoided. To overc these prooier , t e
project can c.e irrpler entec to rn.iruxtize any erosion caused y the steep
slopes ar .1 e i.nao i. ii ty to incorporate the sludcje. ierlanc r cver c.t
of sluuge was nonexistent during the field test. Application of the sludge
on out:rc.ç s sticuld cause no negatwe irpacts ano ray irprove water quality
by reducing the arount of contar u.nated runoff entering the bedrock.
Operation and tt intenance will not be necessary because the goal. is
to establish a natural eastern forest ecosyster t. Consistent with Sect .on
121 of the Superfund krendnents and Reauthorization Act of l9 u (SARA)
(P.L. 99— 99), the site woul be revisted every five years to ensure continued
eftccti.veness of the selected alternative.
The cost to u pler ent the alternative would be minimal. The
rm nici.paiities that may apply the sewae sludge and other r er ts
should do so at no cost to EPA, provided the cost of irp1eti nting the
alternative is Less than it costs the rm. nicipalities to dispose of
the sludge.
Catiparative Analysis
o enviror ntal or public health ber f its would result fr ix p1emanting
Alternatives 1. or 2. The re ction of existing or future health risks by
preventing contira ed exposure to matals would not be addressed. Unlike
Alternative 3, the matals would re i.n rrcbile and will continue to cnta nanate
area surface waters by not mini.uu.zirq runoff and erosion. This would not
c rply with the requirenmnts of the Clean Water Act regarding Best ?‘anagemant
Practices (B1W).
Addressing i le ntability, Alternative I does not require an i.rrplerent-
ability analysis since there is no irple ntation issues associated with taking
no action. The effective irtplerrentation of Alternative 2 wcxild depend on the
prcperty ners voluntary placemartt of restrictions in the deed. Based on the
results of field test plots, Alternative 3 is irple”entable, provided their
are reliable sources of sewage sludge to x lete the revegetation of the
defoliated areas.
There are no ts for Alternative I. since this involves no action. The
costs for Alternative 2 are minimal which should involve only U legal
fees for the r thfication of deeds. Likewise, ts for u pleosnti.ng
Alternative 3 would also be ru.ninal, if the cost of applying the sewage sludge
for u. nicipalities is a cost effective r ar of disposal in Lieu of t’.e r
current practices.
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Recoended Alternative
Section 121 of SARA and the current version of the National. C ntingencv
Plan (NCP)(50 Fed. Reg. 47912, November 20,1985) establish a variety of
requir ents relating to the selection of reme aj actions under CERCI..A.
Applying the current evaluation criteria in Table 2 to the three rena n ng
r edial alternac jves we reco mend that AlternatIve 3 be implemented at
at the Palmerton Zinc Superfund Site.
This is art interim r edy for the site. When the RI/F5’s for the
other operable units are completed by the responsible parties, ROD’s
will be Issued to address all aspects of the site. This interim remedy
wtjj. not, however, be inconsistent with a final comprehensive remedy for
the site. This Interim remedy does not attempt to ensure compliance wit t
all AR.ARS for the entire site, but as diSCUSSed abov, under Alternative 3,
will be consistant, to the extent pract cabje, with those action Specific
AR.ARS addressing sludge application, the Clean Water Act and Best Managemert
Practice require e ,
This alternative consists of using a mixture of sewage sludge and
fly ash to revegetate the defoliated areas of Blue Mountain. Based on
greenhouse stt ies and results of field test plots it appears that this
technology is feasible.
Although changes may be made to application rates and/or sludge—fly
ash ratios, It appears that a general outline of the procedures for the
revegerstion program would be as follows:
Step 1: Site preparation —— Heavy equipment (i.e., bulldozers)
would be used to install access roads In the areas targeted for
revegetation.
A concrete pad with reasonable berms would be installed to mix
the sludge and fly ash on—site.
Step 2: Ue potash application —— Lime and potash would be sprayed
on the areas targeted for revegecatlon. Lime would be applied at
approx1 tely 10 torts per acre and potash at 80 pounds actual K per acre.
Step 3: Sludge..fly ash application —— The sludge—fly ash mixture
would be applied by spraying the mixture onto the target area. The
sludge—fly ash ratio will be based on further analysis of the field
test plots. The sludge will, be obtained from the Town of Palmercon,
A.llencown, and, if necessary, Philadelphia.
Step 4: Plant target area —— Grasses would be planted by blowing
a mixture of grass seed onto the target area. Studies are continuing
on the feasibility of also blowing tree seed onto the area. It is not
yet clear if tree seed will germinate on the site. If tree seed wiLl
not germinate, seedlings will be planted.
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A
Step 5: Apply r g.ilch — To protect tjie seed and er ait gerrn iriation,
adeçuate rrulcr will have to be appliec. Mul u. may be r c. uced or
elu nat€.d if sprir oats are piartteu in tfle fall. This will provide
winter ver that will Qi by spring. The target area.s can then ce
Seeded witn tfl per nent plant species in the spring, ano the spring
oat stubble will serve as a protective “n Lcn” layer for the perx anent
species seed.
Schedule
The anticipated sd edule is to continue with sane lixn ited design
studies in the Fall of l9 7. Beginning as soon as possible, .it
pro .bly not before the end of l9 7, large scale, ti.ilti—aci e revegetation
will begin. It will take a number of years to t lete the remedial
action, the exact time depending on the ount of sludge available.
E.PA’s goal is to cat lete the project in five years.
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es s:;e. ess Su a
This resprnsiveiess Su nmary iS divid into tne foli —
Sect ions:
sect on I Overview . A discussion of EPA’s preferred remedial
a Lterriat.ije.
Section ii Bac 1 cgrout.id of Cotn:nunity Involvement and Concerns.
A di cus i ri of trie community interest arid CO irnS
raised during remedial planning activities at trie
Palmertori Zinc Superfund Site.
Section n i Summary of Major Comments Received During the Public
Comment Period arid Agency Responses. A summary of
comments and responses received by the general public
and potentially responsible parties.
I. Overview
The proposed remedial action is to revegetate the defoliated areas
of Blue Mountain using a mixture of sewage sludge arid fly ash. An RI,’E
report discussing the environmental arid public health problems ass3c1a
with the defoliated portions of Blue Mountain was prepared by EPA. Th€
report also examined potential methods to address these problems. Base
on trie information in the report, the revegetatiori program is reco nt e-
The RIlE’S report arid a description of the recommended alterna:’.’;e
.ias released for public review arid comment on May 22, 1987, a puolic
meeting was held on June 18, 1987 arid the comment period closed on
July 6, 1987. A total of five...written comments were received.
II. Background of Community Interest and Concerns
The community has generally been concerned about the environmental
devastation arid the negative image the barren mountaian projects. The
action being considered at this time deals only with the mountain,
however, there are two other major contamination problems which have
been of public concern. Widespread soil contamination exists because
of the deposition of heavy metals from past air emissions from the
smelter. There is also significant ground water and surface water
contamination on and near the smelter property.
The public has been concerned about the potential health effects
of the soil arid groundwater contamination and also about the porent aL
financial impact on the zinc company of any remedial action. The
current owners of the smelter, Horsehead Industries, are completing
and RI/FS on the ground water arid surface water problems on arid near
the smelter property. An RIlE’S on the widespread soil, contamination
is being completed by the previous owners of the smelter, Gulf & Wester
Inc. These Rt/FS’s are being done under a consent order with EPA arid
the reports will be available for public review and comment in the
coming months.
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Palmerton Zinc Mining Waste NPL Site Summary Report
Reference 3
Excerpts From Draft Remedial Investigation Report:
The New Jersey Zinc Company, Palmerton, Pennsylvania;
J.F. Gnffen, EPA; July 8, 1987
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• 1 14 ,
RD(EDIAL INVESTIGATION REPORT
1.0 — Introduction
1.1.1. Background Infornation
The New Jersey Zinc Company is located in the Borough of Palmerton
which is situated along the southern boundary of Carbon County, Pennsylvania.
The Borough lies in a narrow valley bounded on the south by the Blue Mountain
and on the north by Stoney Ridge, in the vicinity of Lehigh Gap on the
Lehigh River (see Figure 1.1). The New Jersey Zinc Company occupies approxi-
mately 267 acres in the Borough and consists of two (2) plants — the West
Plant in the western end of the Borough on the northern bank of the Lehigh
River and the East Plant and Cinder Bank in the eastern end of the Borough
on the southern side of the Aquashicola Creek and at the foot of the north
side of the Blue Mountain.
Construction of the West Plant was started in early 1898 with the
first zinc oxide produced from zinc silicate, ores mined in New Jersey.
Zinc metal was produced from the same ores in the first quarter of 1900.
The zinc silicate ores were relatively pure in that they were free of lead
and cadmium. Construction of the East Plant was started in 1910 for the
treatment of zinc suiphide ores which contained small amounts of lead and
cadmium. The process consisted in crushing the ores, removing the sulfur by
burning which replaced the sulfur in the ore with oxygen to produce a low
grade, crude zinc oxide and sulfur dioxide. The crude zinc oxide was
further treated by sintering (forming lumps), mixing with coal and converted
to either a relatively pure zinc oxide (American Process) or zinc metal.
The sulfur dioxide was converted to sulfur trioxide and abosrbed in a weak
sulfuric acid to produce merchantable quality sulfuric acid. These processes
started operation in 1913.
Just prior to World War II (September 1941), the employment reached
a high of 3,600. Maximum annual production reached was approximately 134,000
00 00 1 3
- (I ,’
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A.
1—2
net tons of zinc metal, 93,000 net tons of zinc oxide, 157,000 tons of
sulfuric acid, 40,000 tons of anhydrous aonia, 6,600 tons of rolled zinc
products and miscellaneous by—products.
Shutdown of the basic zinc metal circuit in 1980 due to foreign
imports, depressed prices and high cost of environmental controls reduced
the employment to approximately 630 in 1982. As of mid—1986, 550 were
employed.
Cinders (residues) from the production facilities of both the East
and West Plants have been stocked in designated areas (based on metal values)
along the base of the north side of the Blue Mountain, south and east of the
East Plant since 1913. The Cinder Bank is now approximately 2.5 miles long,
between 500 and 1,000 feet wide at the base and the top up to 100 feet above
the mineral soil layer. At the time of a bank drilling program in l9&l, it
was estimated that 27,500,000 tons of material were stored. Updating this
to December of 1986, indicated that 28,300,000 tons were stored at that
time. The designated areas are generally divided into boiler house and gas
producer ash from anthracite coal, horizontal retort, vertical retort, travel-
ing grate furnace (high and low zinc areas) and Waelz kiln residues, slags
and town refuse.
Residue from the operations was normally quenched in water directly
from the processes, loaded into railroad cars and/or trucks, and transported
to the designated storage area. Here, the material was spread, by locomotive
crane originally and later by front—end loader with compaction originally by
settlement only and later by traveling across the area with the front-end
loaders.
Generally, the major portion of the Cinder Bank is stable. However,
occasionally steam and smoke is seen in certain areas of the bank and minor
subsidences have occurred.
Analyses prior to and during stocking of residues, along with the
drilling program carried out in 1981, indicates the greater percentage of
(10001€
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1—3
the refuse to be ash and carbon with small amounts of metals of wtiicb zinc
is the greatest — averaging 2.7% (see Appendix 1—2). The New Jersey Zinc
Company has performed many investigations on their own volition, as well as
those suggested, requested or demanded by various State and Federal agencies.
The Environmental Protection Agency National Enforcement Center
EPA—330/2—79—022 issued a report “Evaluation of Runoff and Discharge from
New Jersey Zinc Company, Palmerton, Pennsylvania” dated December 1979.
Plant discharges to the Aquashicola Creek and the Lehigh River are covered
by NPDES Permit No. PA—0012751.
The New Jersey Zinc Company is an unincorporated division of Horse—
head Industries, Inc., 204 East 39th Street, New York, NY 10016. The proper-
ties were purchased from Gulf • Western Industries, Inc. on September 30,
1981.
The site shown on Figure 1.1 is located in a narrow valley with
the Stoney Ridge on the north and the Blue Mountain on the south in the
south side of the Borough of Palmerton, as previously noted. The Cinder
Bank is located south of the Aquashicola CreeK along the base of the north
side of the Blue Mountain. Elevation at the base of the Cinder Bank is
approximately 500 feet above mean sea level and the top of the mountain at
approximately 1500 feet above mean sea level. Pbotograetric maps are
attached — Plates 4—1, 4—2, and 4—3. Prevailing winds in the area are
generally westerly, parallel to the valley.
The Borough of Palmerton is on more than ten tracts of land purchased
and sub—divided by The Palmer Land Company, a subsidiary of the original New
Jersey Zinc Company, starting in late 1898. The majority of the population
of the Borough, until the late sixties, was made up of families of employees
of The New Jersey Zinc Company. The counity population was 5,455 at the
time of the 1980 census.
000017
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3—2
of two to four Vertical retorts. Initially, leach tests of these residues
aetermined that they were not hazardous. However, later it was found tnac
some of these residues failed the toxicity test. The operation was shut
down October 11, 1985. The entire 15,000 N.T. will be recycled through the
Waelz kilos and the area closed as per a closure plan submitted to Mr.
Patrick McManus (3HW11), U.S. EPA Region III. (Copy attached marked
Appendix 3—2.)
3.2 Materials Component Characteristics and Behavior
As a whole, the bank was reported to contain 27,500,000 estimated
total tonnage in aforementioned drilling report containing approximately:
16% Carbon, 2.7% Zinc, 0.025% Cadmium, 0.36% Lead, 0.33% Copper,
0.6 Oz/T Indium, Remainder Ash.
Practically all of the above are in the form of oxides and are
contained in materials ranging in size of fine powders through the original
two inch square and two inch by four inch loaf briquets to lumps and layers
of material too hard and/or heavy to be moved with a large bulldozer.
000035
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Palmerton Zinc Mining Waste NFL Site Summary Report
Reference 4
Excerpts From Palmerton Zinc Superfund Site Blue Mountain Project;
EPA Region ifi; Apr11 1987
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4. PUBLIC } ALTH AND EVIR0N) NT j IMPACTS
4.1 E.NVIRO?MENTAL IMP.CTS
The environmental impacts of the metal contamination
on the affected area of Blue (ountain are obvious to the
naked eye. Vegetation is absent, and the soil is
completely eroded. A number of articles, cited in this
chapter, appeared in scientific journals documenting the
environmental damage caused by the contaminants under
study.
4.1.1 Reduction In Microflora
Reduced microbial activity can be seen throughout the
defoliated portions of Blue Mountain. Tree trunks that
fell 10 to 20 years ago have riot decayed, as would occur
in areas with normal bacterial activity. The wood here
has the appearance of dry, weathered driftwood, rather
than of decayed wood commonly found in forested areas.
The absence of microbial activity was documented by
researchers in 1975 (Jordan and Chevalier 1975). The
researchers concluded that over the approximately 40-year
period of accelerating vegetation damage. increasing
denudation, and increasing soil zinc levels, it is
inevitable that the microbial populations have undergone
changes in the Lehigh Gap area, Zinc has affected the
microbial populations by direct toxicity and by secondary
environmental effects, such as destruction of vegetation.
drought, high soil temperatures, elevated pH. loss of soil
nutrients, and decreased input of fresh Iitter;
4.1.2 Reduced Lichen Growth
Lichens are sensitive indicators of environmental
pollution. A study in 1972 (Nash 1972) estimated that. on
the defoliated areas of Blue Mountain, the richness and
abundance of lichen species were reduced by approximately
90 percent. The researcher concluded that the abnormally
high concentrations of zinc in the defoliated areas are
primarily responsible for the poor condition of lichen
flora. Although the smelter was operating at the time of
the lichen study, and sulfur dioxide (SO 2 ) was present
in [ eve Is high enough to cause injury, the SO 2 was not
detected at elevated levels at the periphery of the
Lichen-impoverished zone. Consequently, it was concluded
that the extremely high soil concentrations of zinc were a
more significant factor than SO 2 concentrations in
causing the reduced lichen growth.
4—1
Cb9
(‘ ed)
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,. p _i
4.1.3 Reduced Arthropod Growth
Leaf—litter arthropods are important organisms in the
ecology of healthy forests. Arthropods break down organic
matter (e.g., leaves and bark) and contribute to the
normal flow of nutrients through a healthy forest. On
Blue Mountain. and beyond, researchers have shown that
metal contamination has severely affected the arthropod
population.
In 1978, Strojan reported that total arthropod density
was only 22 percent of that in an uncontaminated area
(Strojan, Emissions . 1978). It was concluded that the
cause of the decrease is the high Levels of soil
pollutants. In another article. Strojan presented data
demonstrating that the reduction of arthropods is creating
an abnormally thick layer of undecayed organic debris
(Strojan. Decomposition , 1978).
In 1984. researchers Beyer. Miller, and Cromartje
reported that the mortality rate of arthropods (woodi ice)
after 8 weeks was 84 to 87 percent in surface litter from
Blue Mountain (Beyer et at. 1984). These researchers
believe that the findings from this and previous studies
demonstrate how the Palmerton smelters are changing the
surrounding environment. The populations of soil
organisms, the soil profile, and the nutrient flow through
the ecosystem have been altered at sites near this
smelter.”
4.1.4 Siznificantly Reduced Ve etat iv . GrowLh
The lack of vegetation in the affected area is
obvious. The first systematic studies to documt.nt the
role of metal contamination in this damage wete tind rtaken
in the early seventies. En an initial study. metal
contamination of the vegetation on Blue Mountain was
documented (Buchauer 1973). In a subsequent repàrr
(Jordan 1975). the •ffects of metal contamination on the
vegetation were further documented, and a number of causes
for the lack of vegetation were presented:
• High soil zinc levels apparently inhibited seed
germination and prevented reestablishment of
vegetative cover.
• En the absence of vegetative cover, soil erosion
occurred, and eroded areas are even less likely
to revegetate.
The lack of vegetative cover exposes the dark
surface to solar radiation. The exposed surface
may attain temperatures as high. as 144F, which
can kill stems of tree seedlings.
4—2
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I
of’ mulch, and other minor variables. At an average of $25
per ton it will cost approxi, t y $2,750 per acre. T
total cost to revegetate the 2,000 acres could be
approximately $5.500.000. The calculations made to derive
these figures are provided in a letter from the City of
Allentown to EPA dated December 29. 1988. This letter s
provided in Appendix F.
It is anticipated that if Philadelphia sludge is used
to expedite the project, similar cost savings will be
available to Philadelphia. The Palmerton sludge would be
delivered to the mountain by the Borough of Palmerton.
Costs that will be assumed by the EPA would be those
associated with procuring experts to provide continuing
design assistance on the project. Experts from
Pennsylvania State University and SCS wilL be used to
continuously refine the design of the project. For
example, sludge—fly ash mixtures, plant species, and other
parameters nay have to be refined as the project
proceeds. It is anticipated that these design —assista 5
costs should not exceed $50,000 per year. These costs
would (funded through inter—agency agreements) Lnclude
travel, salary, and analytical costs associated with
vegetation, soil, and water analysis.
Replacement costs are nil because the project can only
have a net benefit. Currently, the high metal levels and
absence of nutrients preclude any significant vegetation
on the mountain. Application of the sewage sludge and the
other amendments can only serve to benefit Blue Mountain
and would not have to be removed or replaced.
7-20
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Palmerton Zinc Mining Waste NPL Site Summary Report
Reference 5
Excerpts From Remedial Investigation Report:
The New Jersey Zinc Company, Palmerton, Pennsylvania;
EPA; November 20, 1987
-------
4—10
520R09
Upon completion of monitoring well, installation and veil
development, wells were surveyed to determine their locations
and elevations. (Survey criteria were within 0.01 feet
vertically and ± 1 foot horizontally.) Monitoring we].].
elevations are included on the lithologic and well. construction
logs in Appendix 4-1.
4.2.2 Supervision, Sample Collection, and Record Keeping
All drilling activities and veil construction activities were
supervised by REWAI’s on—site project geologists, who were in
constant contact with NJZ’s project coordinator and REWAI’s
project manager. Litholegic samples were collected from bailed
cuttings every five feet and stored in clean glass jars for
future reference. These collected samples are being stored by
NJZ at their East Plant facility. Sample jars were clearly
labeled with the job number, well number, and sample depth
intervals. All observations made by REWAI’s project geologists
are included on the lithologic and well construction logs in
Appendix 4-1.
4.3 Groundwater Sampling Procedures
Upon completion of the unconsolidated aquifer monitoring well
installations, two complete rounds of groundwater sampling were
conducted by REWAI. The first round occurred the week of
August 18, 1986, and approximately corresponded with the August
surface water sampling event. The second round occurred the week
of March 23, 1987, which corresponds seasonally with the March
1986 surface water sampling event. This sampling was not
conducted in 1986 because monitoring wells were not installed at
that time.
( i)OQ i
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520R20
5.0 INTRODUCTION
In compliance with the U. S. Environmental Protection Agency
(EPA) Administrative Order by Consent (AOC) dated September 24,
1985, two (2) required surface water samplings were conducted on
behalf of the New Jersey Zinc Company (NJZ), by R. E. Wright
Associates, Inc. (REWAI). All work associated with the
collection and analysis of surface water samples was completed as
specified by the Task VI Site Operations Plan (SOP), approved by
EPA Region III on March 6, 1986.
Five (5) distinct sampling areas at and around the NJZ East Plant
site were included in these sampling events. These areas were:
o Runoff from Blue Mountain (seeps and springs).
o Runoff from the Cinder Bank (seeps).
o Permitted discharges (NPDES) to Aquashicola Creek.
o Water and sediment samples from Aquashicola Creek.
o Water and sediment samples from the Lehigh River.
The R.EWAI field sampling crew wa, on-sit, between March 10, 1986
and March 14, 1986 and then again between August 11, 1986 and
August 15, 1986 to conduct all fieldwork associated with these
sampling events • Flows in both the Aquashicola Creek and Lehigh
River during the March sampling period were high due to
precipitation and snowmelt, thus characterizing conditions during
the “wet season.” Flows during the August sampling period were
much lower, and thus characterized the “dry season.”
000112
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qi
Mining Waste NPL Site Summary
Sharon Steel/Midvale Tailings Site
Midvale, Utah
U.S. Environmental Protection Agency
Office of Solid Waste
June21, 1991
FINAL DRAFT
Prepared by:
Science Applications International Corporation
Environmental and Health Sciences Group
7600-A Leesburg Pike
Falls Church, Virginia 22043
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DISCLAIMER AND ACKNOWLEDGEMENTS
The mention of company or product names is not to be considered an
endorsement by the U.S. Government or by the U.S - Environmental
Protection Agency (EPA). This document was prepared by Science
Applications International Corporation (SAIC) in partial fulfillment of
EPA Contract Number 68-WO-0025, Work Assignment Number 20.
A previous draft of this report was reviewed by Sam Vance of EPA
Region Vifi [ (303)293-1523], the Remedial Project Manager for the
site, whose comments have been incorporated into the report.
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Mining Waste NPL Site Summary Report
SHARON STEEIJMID VALE TAILINGS sim
MIDVALE, UTAH
INTRODUCTION
The Site Summary Report for Sharon Steel/Midvale Tailings is one of a series on mining sites on the
National Priorities List (NPL). The reports have been prepared to support EPA’s mining waste
program activities. In general, these reports summarize types of environmental damages and
associated mining waste management practices at sites on (or proposed for) the NPL as of February
11, 1991(56 Federal Register 5598). This summary report is based on information from EPA files
and reports and on a review of the summary by the EPA Region VIII Remedial Project Manager for
the site, Sam Vance.
SiTE OVERVIEW
The Sharon Steel/Midvale Tailings site is the milling portion of a former milling and smelting
operation originally owned and operated by U.S. Smelting (later renamed U.S. Smelting, Refining
and Mining Company). Operations involved the milling and smelting of lead, copper, and zinc. The
Mill site is approximately 260 acres, and is located in the City of Midvale, Utah, which is 12 miles
south of Salt Lake City. The Mill site is bordered by streets to the north, northeast, and southeast
and by the Jordan River to the west and south. Directly north of the site, where the smelter
operations were conducted, a slag pile from smelting operations was generated, which constitutes the
Midvale Slag NPL site. A separate NPL Site Summary Report has been completed for that site.
The Sharon Steel/Midvale Tailings Mill site includes the tailings source area, tailings piles, Mill
buildings, and wetlands (Reference 1, page 1-4; Reference 2, page 2; Reference 3, pages 1-4 and 1-
5). Figure 1 depicts the approximate boundaries of the Mill site as well as the more expansive study
area for the Remedial Investigation/Feasibility Study. Approximately 14 million cubic yards of
tailings were generated from past milling operations on the site (Reference 3, page 1-1). The 1990
estimated population within 2 miles of the site was 43,911 people. In the City of Midvale (less than 1
mile from the tailings piles), the 1990 estimated population was 12,085 (Reference 1, page 4-7). The
site was proposed for the NPL in 1984, and added to the list in August 1990 (55 Federal Register
35502; Reference 3, page 1-10). The Remedial Investigation was conducted from July 1987 to 1988.
The Feasibility Study was published in June 1989; in July 1989, the EPA Region Vifi Supethmd
Program Proposed Plan was issued for the entire site. After extensive public comment on the
Proposed Plan, EPA decided to postpone the Record of Decision (ROD) for a year and divide the site
1
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Sharon SteellMidvale Tailings Site
SHARON STEELJMiOVAL..E TAIUNGS SITE
MIDVALE. UTAH
N f l Sits & Study Aria
Carna O’ ss.r 6 MeKo. Inc . C2 kd. by..! .L Figura No.
CDU Oazo: i ! ! ”Se I
FIGURE 1. MILL SITE AND STUDY AREA
I
I
SLts Boundary
Aria Boundary
.1
I.
112
N Sc..
2
L
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Mining Waste NPL Site Summary Report
into two Operable Units for further Remedial Investigation/Feasibility Study investigations (Reference
8, page 2).
Operable Unit 1 is the Mill site, including tailings and ground water; Operable Unit 2 consists of the
“study area” in Figure 1 (excluding the Mill site area). Operable Unit 2 includes offsite soils,
residential areas, and public-use areas adjacent to the mill; (Reference 3, page 1-7; Reference 4, page
1). The primary constituents of concern in the soil are arsenic, cadmium, and lead (Reference 1,
page 2-13). The primary constituent of concern in the ground water is arsenic (Reference 10,
Appendix A, page 5-1).
The ROD for Operable Unit 2 was signed on September 24, 1990. The selected remedial action
includes excavation of the contaminated soils from the residential areas and the temporary storage of
these soils at the Mill site. The estimated remediation cost for Operable Unit 2 [ capital and Operation
and Maintenance (O&M) costs] is approximately $20 million (Reference 4, page 16). The Feasibility
Study and the Proposed Plan for Operable Unit 1 were released for public comment on October 5,
1990 (Reference 3, page 1-1). The ROD for Operable Unit 1, estimated to be completed in
December 1991, will address remediation of the residential soils stored at the Mill site, tailings
present at the Mill site, and contaminated ground water underlying the Mill site (Reference 4,
Abstract, page 1; Reference 9).
OPERATING HISTORY
U.S. Smelting conducted both milling and smelting operations at the site. The milling portion of the
facility operated from 1910 to 1971. In 1971, UV Industries bought U.S. Smelting. The smelter,
located to the north of 7800 South Street (see Figure 1), is on the Midvale Slag Superfund Site, and
was closed in 1958. Sharon Steel acquired the Mill and tailings site in 1979. The original operations
involved receiving lead, copper, and zinc ores; extracting sulfide concentrates of these metals in the
milling operation; and smelting these concentrates to extract the metals in purer form. The facility
also operated as a custom mill, receiving ores and concentrating and extracting metals. The wastes
from the milling operations were disposed of in unconsolidated tailings piles. The Mill site includes
several Mill buildings and approximately 12 to 14 million cubic yards of tailings in uncovered piles
(Reference 1, page 1-4; Reference 3, pages 1-8 and 1-9; Reference 6, page 14).
In June 1982, wind-blown tailings were sampled and found to have high concentrations of arsenic,
cadmium, chromium, copper, lead, and zinc (Reference 3, page 1-9). A 6-foot chain-link fence was
erected by Sharon Steel along the northern boundary of the property to prevent direct contact with the
tailings piles. The fence, however, did not prevent the tailings from blowing down the embankment
3
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Sharon Steel/Midvale Tailings Site
of a highway right-of-way (Reference 3, page 1-12). On September 17, 1982, the Utah State Bureau
of Air Quality issued a request for a compliance plan to control the fugitive dust emanating from
Sharon Steel (Reference 7, page 4; Reference 3, page 1-9). Sharon Steel Corporation responded to
this request in October of that year with a proposal to use water flooding to suppress the dust. The
State withdrew initial approval of the plan, and ordered Sharon Steel to design an alternative plan.
Ultimately, a dust-mitigation program (using a chemical polymer dust suppressant) was implemented
in May and June of 1988 (Reference 3, pages 1-9 and 1-13).
Also in 1988, a slope-stabilization and river bank-restoration plan was implemented. Where the berm
bordering the site had been washed out by high river flows, it was reconstructed to serve as a buffer
zone between the tailings and the River. Rehabilitation involved removing all tailings from the berm
where it had been washed out. These tailings were placed on existing piles away from the River, and
embankments were sloped at a ratio of approximately 3 to 1 in a horizontal to vertical configuration.
In addition, stream-bank areas requiring repair were filled with gravel material, compacted, and
covered with a graded rip-rap. Debris and sediments that were directing River flow into the tailings
side of the River were also removed and the River channel was “cleaned” so that River flow would be
redirected away from the bank bordering the tailings (Reference 3, pages 1-13 and 1-14).
SiTE CHARACTERIZATION
The Mill site has three small offices, a bunkhouse, a machine-storage shed, and three Mill buildings.
A 22-acre wetlands area and several small ponds are also located on the Mill site, along with the
tailings piles. The sources of contamination at the site are the tailings piles (Reference 2, page 2).
Descriptions of each potentially contaminated medium are presented below.
Ground Water
The original Remedial Investigation/Feasibility Study for the Sharon Steel Mill site, completed in June
1989, provided a general background on the ground-water system and its quality underlying the site.
In response to public comment on the original Proposed Plan and Remedial Investigation/Feasibility
Study, a ground-water/geochemistry Remedial Investigation Addendum was begun in November
1989, and completed in May 1990. This in-depth study was conducted to understand, in further
detail, the geology, hydrologic system, and geochemistry of the site.
Four aquifers comprise the ground-water system at the Mill site. Two of these hydrologic units are
regional aquifers: the Deep Principal Aquifer and the Upper Sand and Gravel Aquifer. They are
4
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Mining Waste NPL Site Summary Report
similar in their regional extent, composition, and depositional history. Two local aquifers were
identified: the Perched Terrace Aquifer and the Saturated Tailings Zone (Reference 9, page 4-1).
The Deep Principal Aquifer, composed of unconsolidated clay, silt, sand, and gravel deposits, is
confined by a thick (6.5 to 24.1 feet at the site) clay, silt, and fme-sand layer in the central part of the
Valley and is generally unconfined along the perimeter of the Valley (the recharge area of the
Aquifer) (Reference 9, pages 3-1 and 3-9). Beneath the Mill site, ground-water flow in the Aquifer is
to the northeast toward pumping centers (Reference 9, page 4-1). During most of the year, the
Aquifer displays artesian conditions in the site study area; however, high rates of summer pumping
may reverse this gradient, as was observed in the summer of 1990 (Reference 9, page 3-11). The
Remedial Investigation cautioned that this reversal could become more persistent if pumping were to
continue year-round at rates similar to those occurring during the summer (Reference 9, page 4-1).
The Upper Sand and Gravel Aquifer is similar in composition to the underlying Deep Principal
Aquifer. Overlying the Upper Sand and Gravel Aquifer is a discontinuous clay and silt layer that
separates this Aquifer from the tailings at the Mill site (Reference 9, Executive Summary, page 6).
Beneath the Mill site, ground-water flow in the aquifer is to the northwest most of the year; however,
later in the summer, the flow direction has been observed to change to a northern direction
(Reference 9, Executive Summary, pages 6 and 7; Reference 9, page 3-8). The onsite upward head
difference between the Deep Principal Aquifer and the Upper Sand and Gravel Aquifer indicates that
upward leakage from the Deep Principal Aquifer is occurring. However, locally, slight downward
gradients exist, perhaps related to recharge from overlying units or from pumping of large municipal
wells completed in the basal portion of this Aquifer and the Deep Principal Aquifer (Reference 9,
page 3-9).
The two local hydrologic units present in the study area, the Perched Aquifer and the Saturated
Tailings Zone, lie laterally adjacent to each other. The Perched Aquifer is located on the east side of
the Mill tailings in the ancient Lake Bonneville clay, silt, and fine-sand deposits that form a terrace
above the Jordan River (Reference 9, Executive Summary, page 7 and page 3-3). In general,
recharge into this Aquifer percolates into the underlying Upper Sand and Gravel Aquifer; however,
water may become perched above impermeable layers. In addition, some ground water flows from
the Perched Aquifer into the Saturated Tailings Zone (Reference 9, page 3-4). The Saturated Tailings
Zone is comprised of fine-grained metalliferous sand and silty sand and interbeds of slimes (low-
permeability silts/clays) hydraulically deposited into tailings ponds constructed on the River’s
floodplain. At some locations, the tailings directly overlie the Upper Sand and Gravel Aquifer at
what may be the pre-1951 channel of the Jordan River. In the 1950’s, the Jordan River was diverted
west to increase the area available for tailings disposal. Ground water is generally found in the lower
portion of the tailings; flow is both lateral and downward through Jordan River overbank deposits, or
5
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Sharon Steel/Midvale Tailings Site
the buried Jordan River channel (Reference 9, pages 3-4 through 3-6). Some water remains above
the slime interbeds. In November 1987, water levels indicated a fairly uniform ground-water gradient
to the west; however, June 1990 measurements indicated different flow paths. Ground-water flow
was determined to be to the north in the northwest part of the tailings and to the east and northeast in
the western portion of the tailings (Reference 9, page 3-6). Overall, ground-water levels are
decreasing in the tailings due to the discontinuation of dust-suppression activities (Reference 9, page
3-6).
The Deep Principal Aquifer is the primary drinking-water source in the Salt Lake Basin, serving
300,000 people. The nearest operating municipal supply well is approximately 1.5 miles north
(downgradient) of the site. According to the State of Utah, the present allocation of water rights
exceeds Aquifer recharge potential (Reference 3, pages 1-15 and 1-24). Both the Deep Principal
Aquifer and the Upper Sand and Gravel Aquifer are potential sources of drinking water for Salt Lake
County, which is north of the site (Reference 1, page 4-2). In the study area, two large-volume
public supply wells pump water from the lower Upper Sand and Gravel Aquifer and the Deep
Principal Aquifer (Reference 3, pages 1-15, 1-23, and 1-24; Reference 10, Executive Summary, page
6).
The location of the tailings provides the potential for the migration of contaminants to the
unconsolidated deposits of the Jordan River Valley. Of 14 tailings samples, 10 were reported as
exceeding Extraction Procedure (EP) toxicity test limits for lead, and 3 exceeded EP toxicity test
limits for cadmium. One soil sample collected from the Mill site also exceeded the EP toxicity
criteria for lead (specific levels were not provided) (Reference 3, page 1-23).
Chemical analyses of solid materials and water from below the tailings confirm that contaminants are
migrating from the tailings into these materials. Onsite sampling concluded that contaminant
concentrations decrease with depth in materials immediately below the tailings.
Wells completed in the tailings have the highest arsenic [ average value 920 micrograms per liter
(jzgll)] and Total Dissolved Solids (TDS) values (Reference 9, pages 3-23, 3-24, 4-2, and 4-3).
Perched Aquifer ground-water samples collected from both onsite wells and wells in the vicinity of
the site have arsenic concentrations ranging from 4.2 to 31.6 g/l. The 31.6 igfl sample was
collected from a well on the site (Reference 9, page 3-24). Ground-water samples from the upper
portion of the Upper Sand and Gravel Aquifer show concentrations of arsenic ranging from less than
1 to 288 g/l, with an average of 68 zg/l. TDS values ranged from 1,530 to 2,420 milligrams per
liter (mg/I). Arsenic concentrations detected in upgradient wells are generally 1 g1l (Reference 9,
pages 4-2 and 4-3). Concentrations of arsenic and TDS in the upper portion of the Upper Sand and
Gravel Aquifer suggest a mixing of water in the upgradient Aquifer with water from the tailings.
6
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Mining Waste NPL Site Summary Report
Three wells completed in the Deep Principal Aquifer beneath the tailings site have very low arsenic
concentrations (generally below detection limits) and low TDS values. Ground-water samples of
private wells completed in this Aquifer show the same analytical results. These values suggest that
arsenic has not yet migrated to the Deep Principal Aquifer, or that dilution has taken place (Reference
9, pages 3-23, 3-24, 4-3, and 4-4). The geometric mean of ground-water (and other media)
contaminant concentrations are presented in Table 1 (Reference 10, page 1-17).
Soils in the Midvale area vary with the three local land features: the Jordan River floodplain; terraces
from the Great Salt Lake/Lake Bonneville system; and artifacts of the mining industry (tailings dumps
and man-made fill) (Reference 3, page 1-16, Reference 1, page 4-3). Levels of metals found in the
soils and tailings are presented in Table 1. The mean lead concentration at the Mill site, for example,
was 2,100 milligrams per kilogram (mg/kg), and in residential soils it was 722 mg/kg, with no
samples for either location below 150 mg/kg lead (Reference 3, pages 1-28 and 1-29). Results of a
geochemistry study completed by Drexlor in 1989, which was reported in the 1990 Baseline Risk
Assessment, suggest that both the tailings and slag sites have contributed to lead levels in the soil
(Reference 1, pages 2-8 and 2-9). The geometric mean of soil (and other media) contaminant
concentrations are presented in Table 1.
Surface Water
Some of the sites, including most of the tailings piles, lie in the floodplain of the Jordan River. At
one time, the River flowed through the Mill site, but was later relocated to the west of the site to
facilitate tailings deposition. The tailings piles, which form an embankment on one side of the Jordan
River, lack any provisions for containment or diversion of surface-water runon or runoff (Reference
1, page 4-3).
Water-quality data suggest that the dissolution of metals from the tailings to the aqueous phase is
occurring; but, it is not significant. This could be a result of: (1) low fluvial transport of sediment
or tailings material, as indicated by low Total Suspended Solids (TSS) values (59 to 61 mg/I) or (2)
high pH values (7.5 to 7.8) in the Jordan River, which would cause metals to remain bound to the
sediments (Reference 3, page 1-40).
7
-------
n - Number of samples
BDL - below detection limit
TABLE 1. GEOMETRIC MEAN OF CONTAMINANTS OF CONCERN IN VARIOUS MEDIA
I
I
‘“Local Background” as defined in the Remedial Investigation (CDM, 1988b). It was referred to as “ubiquitous contamination” in the Feasibility Study.
2 No samples were collected from the deep confined aquifer because previous research showed no contamination.
‘Geometric mean exceeds Maximum Containment Level (MCL) for dnnking water.
Source: Reference 3, page 1-28
00
Element
Local Background’ Soil
Contaminated Surface Soil
Tailings
Terrace
Floodplain
Terrace
floodplain
Residential
Mill Site
Surface
(Oxidized)
Surface
(Dunes)
Subsurface
(Unoxidized)
(mg/kg)
Aluminum
13,669.0
7,283.0
12,461.0
10,883.0
9,560.0
9,267.0
3,982.0
3,270.0
3,002.0
Antimony
6.1
< 5.5
6.4
8.8
5.7
72.7
73.5
16.0
17.0
Arsenic
15.2
5.7
31.5
40.7
65.5
158.0
425.1
320.2
411.2
Cadmium
3.2
2.0
5.4
7.1
12.5
27.6
46.8
37.3
36.4
Chromium
18.0
11.9
17.8
18.6
15.8
29.8
25.4
17.0
18.3
Copper
81.4
40.7
160.6
344.6
195.1
324.1
298.5
760.2
578.1
Lead
97.0
78.6
373.2
536.8
722.0
2,100.0
6,278.0
5,470.0
5,209.0
Manganese
454.3
249.5
466.0
452.8
508.9
833.7
1,199.0
1,497.0
2,032.0
Silver
1.4
< 1.4
1.9
2.8
3.0
10.4
26.9
24.9
27.1
Thallium
BDL
BDL
BDL
1.6
1.4
2.0
3.3
3.2
8.0
Zinc
124.3
4.0
100.3
5.0
320.8
23.0
537.4
17.0
591.8
22.0
2,143.0
31.0
4,821.0
13.0
6,048.0
22.0
6,372.0
4.0
n
/07
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Mining Waste NPL Site Summary Report
ENVIRONMENTAL DAMAGES AND RISKS
An environmental health problem was first suspected in June 1982 when the Utah State Department of
Health was notifi d that citizens were gathering wind-blown tailings for sandboxes and gardens. Sand
and wind-blown tailings were sampled by the State. High concentrations of arsenic, cadmium,
chromium, copper, lead, and zinc were found (Reference 1, 1-4; Reference 2, page 2; Reference 7,
page 1; Reference 3, page 1-9). A sample of “sand” analyzed by the State contained 4,000 parts per
million (ppm) of lead (Reference 6, page 14).
The City of Midvale, less than 1 mile away, has a population of 12,085, and within 2 miles of the
site there are 43,911 people. The Jordan River is classified for recreational use, excluding
swimming, cold-water game fishing, and agriculture (Reference 1, page 4-3).
Contaminants of concern in the Mill tailings are aluminum, antimony, arsenic, cadmium, chromium,
copper, lead, manganese, silver, thallium, and zinc. Arsenic, cadmium, and lead are likely to be of
greatest potential concern to human health, as discovered in the Endangerment Assessment performed
as part of the Remedial Investigation (Reference 1, page 6-3).
The exposure pathways evaluated for current and potential future use conditions are:
• Direct ingestion of site tailings or contaminated surface soils
• Ingestion of contaminated ground water
• Inhalation of tailings-contaminated dust
• Ingestion of home-grown produce by nearby residents
• Dermal adsorption of tailings or contaminated surface soils
• Ingestion/contact with contaminated surface water and sediments (Reference 1, page 6-3;
Reference 3, pages 3-21 and 3-22; Reference 10, page 3-3).
In the Baseline Risk Assessment, arsenic is the only carcinogen evaluated for all exposure pathways
except inhalation. For the inhalation pathway, both arsenic and cadmium are carcinogenic. The
excess upperbound lifetime cancer risks for all current use exposure pathways combined is 5 x
primarily from exposure to arsenic from ingestion of tailings in sandboxes and ingestion of indoor
dust (note that the ground-water pathway is currently incomplete). However, “public information
efforts by the State of Utah and EPA have generally eliminated the route of exposure involving
11
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Sharon SteelfMidvale Tailings Site
efforts by the State of Utah and EPA have generally eliminated the route of exposure involving
tailings ingestion from sandboxes.” Noncarcinogenic effects can also result from exposure to arsenic
and cadmium through the evaluated pathways (Reference 1, page 5-2).
The overall excess upperbound cancer risk for all exposure pathways, except ground water, under
future use conditions is 1 x i0 , resulting primarily from exposure to arsenic through indoor dust and
tailings ingestion. Noncarcinogenic adverse effects could also occur due to exposure to arsenic and
cadmium (Reference 1, page 5-2).
Of greatest concern is the ingestion of lead from the tailings study area that can cause noncarcinogenic
adverse effects. Exposure of young children to lead may cause cognitive dysfunction and reduced
growth, and in adults, hypertension may result from high lead-blood levels (Reference 1, page 5-8;
Reference 3, page 1-25).
Assessment of the ground-water pathway is currently incomplete at the site; however, a future use and
hypothetical current use scenario was examined in the Baseline Risk Assessment for ground water
(Reference 10, Appendix A, page 5-1). Arsenic is the only contaminant of concern identified for the
ground-water pathway.
Current domestic ground-water usage from hypothetical onsite and offsite (downgradient) wells
completed in the upper portion of the Upper Sand and Gravel Aquifer would result in potential
upperbound excess cancer risks of 4.4 x i0 and 1.2 x 10 , respectively (Reference 10, Appendix A,
page 5-1). In addition, there would be a potential for noncarcinogenic adverse health effects from the
use of ground water produced from the onsite well. A future use scenario (arsenic concentrations
were determined with a ground-water quality model) suggests that potential upperbound excess cancer
risks for the years 2020 and 2090 would range from 5.6 x 1CP to 8.8 x 10 for an onsite domestic-
use well and 1.2 x 10 to 5.6 x 10 for an offsite well. Noncarcinogenic adverse health effects are
likely for th onsite domestic well; but, they are unlikely for the offsite domestic well (Reference 10,
Appendix A, pages 5-4 and 5-5).
The combined risk from all pathways, including ground water, was determined for two future use
scenarios based upon current water quality, hypothetical onsite residential use, and the offsite
residential use. The excess upperbound lifetime cancer risk resulting from all exposure pathways for
an onsite resident is 5.4 x i0 . The excess upperbound lifetime cancer risk resulting from all
exposure pathways for an offsite resident is 1.7 x 10 (Reference 10, Appendix A, pages 6-1 through
6-3). In addition, adverse noncarcinogenic health effects are likely for each residential scenario.
12
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TABLE 1. GEOMETRIC MEAN OF CONTAMINANTS OF CONCERN IN VARIOUS MEDIA (Continued)
Element
Sediment
Jordan River Surface
Water
Ground Water 2
Air Data From December
1987 Event
Upstream
Downstream
Upstream
Downstream
Perched in
Tailings
Shallow
Unconfined
Upwind
Downwind
(mg
1kg)
pg/I
Aluminum
1,492.0
3,365.0
1,010.0
1,030.0
60.0
54.0
--
--
Antimony
< 29.0
< 34.0
< 60.0
< 60.0
73.0
62.0
--
--
Arsenic
1.5
16.1
14.0
10.0
109.0’
29.0
314.0
438.0
Cadmium
< 1.5
2.2
0.36
0.44
< 3.0
5.0
< 3.0
25.2
Chromium
3.8
7.3
< 3.0
< 3.0
< 3.0
< 3.0
8.4
108.0
Copper
4.0
151.0
7.0
10.0
3.5
7.1
24.0
787.0
Lead
5.8
115.0
6.0
11.0
6.4
5.3
37.0
3,865.0
Manganese
38.2
128.9
53.0
53.0
305.0
79.4
—
—
Silver
< 2.0
3.0
< 0.2
< 0.2
< 4.0
< 4.0
--
—
Thallium
BDL
BDL
< 10.0
< 10.0
BDL
I3DL
--
—
Zinc
16.0
3.0
331.0
3.0
19.0
1.0
20.0
1.0
62.0
7.0
195.0
7.0
90.0
2.0
5,422.0
5.0
n
n - Number of samples
BDL - below detection limit
‘“Local Background” as defined in the Remedial Investigation (CDM, 1988b). It was referred to as “ubiquitous contamination” in the Feasibility Study.
2 No samples were collected from the deep confined aquifer because previous research showed no contamination.
3 Geometric mean exceeds MCL for drinking water.
2.
I
Source: Reference 3, page 1-28
-------
Sharon Steel/Midvale Tailings Site
None of the surface-water sample analyses found metals to be in excess of the criteria for protection
of aquatic life, except for the seep along the side slope of the tailings above the Jordan River.
Despite high metal concentrations in the seep, River-water quality does not appear to be adversely
affected. The geometric mean of sampling results is presented in Table 1 (Reference 3, pages 1-28,
1-40, and 1-41).
Sediment
The Sharon Steel/Midvale Tailing site is located in the Jordan Valley, which is a flat, sediment-filled
Valley separated by fault-block mountains. The Valley has been filled with lacustrine sediments
deposited in ancient Lake Bonneville, interlayered with coalescing alluvial fans derived from the
adjoining mountains (Reference 1, page 4-2; Reference 3, page 1-14). Sediment data indicate that
tailings are migrating from the Mill site into the Jordan River due to either ongoing erosion or
previous slope failures. However, as previously stated, such migration is not causing significant
dissolution in the aqueous phase. In addition, these data indicate that wetland sediments contain
tailings. Sediment data are presented in Table 1 and the attached references (Reference 3, pages 1-40
through 1-42).
Air
During dry, windy periods in mid- to late-summer, contaminants may be transmitted through the air,
causing inhalation exposure. This may also occur during off-road vehicle use at the Mill site, and to
a lesser extent, during removal or stabilization as part of a potential site remedial action (if protective
measures are not taken). The effect on health from inhalation exposure depends on the proximity of
individuals to the site and particle size. Small particles (less than 10 microns), which may be carried
farther than larger particles, could potentially affect more people; however, only a small proportion of
the tailings particles are that small (Reference 3, page 1-23). Therefore, only nearby exposure may
cause threats to human health. No indication of the exposure level was provided.
Air samples were taken in December 1987. Downwind concentrations of lead and zinc were at very
high levels (3,865 and 5,422 g/l, respectively). Other metal concentrations found in these samples
are presented in Table 1 (Reference 3, page 1-23). Further details of the type of air sampling (i.e.,
particle size) or distance of downwinds samples from the source were not provided in the Feasibility
Study (Reference 3).
10
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Mining Waste NFL Site Summary Report
Modeled future ground-water quality was also investigated to determine human health risks for future
use scenarios (for both onsite and offsite residents). Health risks for these scenarios are predicted to
increase over time due to the increased degradation of ground-water quality, as calculated by ground-
water quality modeling (Reference 10, Appendix A, pages 6-3 and 6-4).
Potential threats to environmental receptors including vegetation, aquatic life, and wildlife were also
evaluated. Soil lead levels as low as 100 ppm are known to be phytotoxic. The geometric mean
contamination level of lead in residential soils was found to be 722 mg/kg (see Table 1), far above the
phytotoxic level (Reference 3, page 1-26 through 1-28). Aquatic life can be exposed to contaminants
in both surface water and sediments. Of greatest concern are the high levels of metals in the
sediments (see the previous section), which may act as a reservoir that can supply metals to the water
column or be directly consumed by benthic organisms. Wildlife in the wetlands may be exposed to
site-related contaminants through direct contact with surface waters or sediments or through the food
chain. Among the metals present at the study area, lead has been shown to bioconcentrate in insects,
small mammals, and songbirds (that may then be consumed by larger animals). While the potential
of adverse effects due to lead exposure exists, it is presently unknown whether wildlife is being
adversely affected by the metals found in the study area (Reference 3, page 1-27).
REMEDIAL ACTIONS AND costs
The October 1990 EPA Region VIII Superfund Program Proposed Plan announced EPA’s preferred
site remediation for Operable Unit 1. The preferred remedial action was listed as site capping,
ground-water treatment, and institutional controls. However, EPA is continuing to evaluate the
reprocessing of tailings as an alternative for remediation at Operable Unit 1. The U.S. Bureau of
Mines is currently conducting a two-phase study to characterize the tailings and evaluate methods for
their beneficiation. The preferred remedy outlined in the Proposed Plan includes the following
activities:
• Installing a multi-layer vegetated soil cap over tailings and soils that exceed the action levels
established for residential soils at Operable Unit 2.
• Pumping and treating contaminated ground water to reduce arsenic concentrations to action
levels. The Feasibility Study for Operable Unit 1 specifies an ion-exchange treatment for the
remedy that was selected; however, the Proposed Plan did not state the specific treatment to be
used.
• Diverting storm water from the site through a drainage system.
‘9 13
-------
Sharon SteelIMidvale Tailings Site
• Regrading the tailings bordering the Jordan River to prevent erosion.
• Excavating contaminated wetland sediments and placing them on tailings prior to capping; and
restoring wetlands.
• Decontaminating, (possibly) demolishing, and disposing of Mill facility and support buildings
offsite.
The 30-year present worth capital and O&M costs for the selected remedy are estimated to be
$43,138,000 (Reference 10, Appendix C, pages 8 through 10). EPA will continue dust-suppression
activities until final implementation of a remedy.
The remedy selected in the 1990 ROD for Operable Unit 2 (offsite residential soils) includes the
following activities (Reference 4, pages 17 and 18):
• Testing soils on each property prior to any action.
• Offering relocation during construction activities if testing of the hazards associated with
construction at a vacant, contaminated lot in Midvale shows that relocation is advisable because
of violations of the National Ambient Air Quality Standards.
• Removing contaminated household dust from residences when lead concentrations in the dust
are greater than 500 ppm.
• Removing existing garden soils down to 18 inches (for soils with concentrations of lead greater
that 200 ppm and arsenic greater than 70 ppm). Institutional controls will be employed to
regulate the installation of new gardens.
• Removing contaminated soils that are not covered by pavement or structures that contain
concentrations greater than 500 ppm lead and 70 ppm arsenic. The depth of excavation, based
on data gathered during the Remedial Investigation, is not expected to exceed 24 inches.
• Replacing excavated areas with clean fill (up to the original grade).
• Revegetating the soil to initial conditions.
• Temporarily storing contaminated soils at the Mill site (Operable Unit 1), separating them from
the tailings, and placing them where they will be included in the final remedy for Operable
Unit 1.
• Installing a plastic liner under (and over) the excavated soil which will be stored at Operable
Unit 1. This liner will prevent redispersal of the soils before remediation of Operable Unit 1.
14
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4
Sharon SteelfMidvale Tailings Site
FIGURE 2. SOIL EXCAVATION AND DISPOSAL
O.U. 2
RESIDENTIAL SOILS
REMOVE AND DISPOSE REMOVE CONTAMINATED
OF SOD AND VEGETATION SOIL AND DISPOSE OF
AT THE MILL SITE
O.u.1
I
REPLACE WITH
CLEAN SOIL
MILL SITE
RE VEGETATE
. I
A
I PLACE CONTAMINATED SOIL
I ON LINER AND COVER
I WITH PROTECTIVE CAP;
• SOIL WILL BE KEPT
SEPARATE FROM TAIUNGS
before
• 1i J’ ’C
;EAN SOIL > j
after
.1
16
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Mining Waste NPL Site Summary Report
Implementing institutional controls to require building permits prior to construction during
removal or replacement of pavements or foundations. Such activities may expose contaminated
soils left in place by remediation and such activities will require special precautions. A
“citizens repository” may be created to provide a place for residents to dispose of soils during
future activities.
The 30-year present worth capital and O&M costs for the selected remedy are estimated to be
$22,650,000 (Reference 4, Table 7). Figure 2 is a graphical depiction of the selected remediation
activities for residential soils.
CURRENT STATUS
The site was listed on the NPL on August 30, 1990 (55 Federal Register 35502). The ROD for
Operable Unit 2 was signed on September 24, 1990. According to EPA Region VIII, the State of
Utah is leading the Remedial Design Phase for Operable Unit 2. A final Remedial Design was
expected by the end of May 1991. The Remedial InvestigationfFeasibility Study and the Proposed
Plan for remediation for Operable Unit 1 were released for public comment on October 5, 1990. The
associated ROD is projected for completion in December 1991 (Reference 5).
15
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Sharon Steel/Midvale Tailings Site
BIBLIOGRAPHY
Camp, Dresser & McKee. Final Feasibility Study Report for the Mill Site Operable Unit 1 of the
Sharon Steel/Midvale Tailings Site, Midvale, Utah, and Appendices. July 14, 1989.
EPA. Interim Baseline Risk Assessment for the Sharon Steel/Midva.le Tailings Site, Midvale, Utah,
Draft. April 23, 1990.
EPA. Interim Baseline Risk Assessment for the Sharon Steel/Midvale Tailings Site, Midvale, Utah,
Appendix A: Recommended Health-Based Soil Action Levels for Residential Soils. May 11,
1990.
EPA Region VIII. Proposed Plan for the Mill Site, Operable Unit No. 1, Sharon Steel Site, Midvale,
Utah. October 1990.
EPA Region VIII. Superfund Program Proposed Plan, Sharon Steel/Midvale Tailings Site, Midvale,
Utah. July 1989.
EPA Region Vifi and the Utah Depamnent of Health. Declaration for the Record of Decision -
Sharon Steel (Operable Unit 02) Residential Soils, Midvale, Utah. September 24, 1990.
Lamb, Laurie (SAIC). Meeting Notes Concerning Sharon Steel/Midvale Tailings Site to Sam Vance,
EPA Region VIII. March 26, 1991.
Prepared for EPA by Camp, Dresser & McKee. Remedial Investigation Addendum for
Sharon Steel/Midvale Tailings Site, Midvale, Utah, 1989-1990 Ground Water/Geochemistry
Data Report. Undated.
Prepared for EPA by Camp, Dresser & McKee. Feasibility Study, Operable Unit 1, Mill and
Tailings Site, Sharon Steel/Midvale Tailings Site, Midvale, Utah, Volumes I and II. October
1990.
Prepared for EPA Region Vifi by Ecology and Environment, Field Investigation Team. Potential
Hazardous Waste Site - Site Inspection Report, Sharon Steel Corporation. March 14, 1983.
Prepared for EPA Region VIII by Ecology and Environment, Field Investigation Team.
Potential Hazardous Waste Site Identification and Preliminary Assessment, Sharon Steel
Corporation. March 14, 1983.
Prepared for EPA Region Vifi by Pat Janni (Ecology and Environment, Field Investigation Team).
Report on the Preliminary Assessment/Site Inspection of Sharon Steel Corp. March 15, 1983.
18
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Mining Waste NPL Site Summary Report
REFERENCES
1. Interim Baseline Risk Assessment for the Sharon Steel/Midvale Tailings Site, Midvale, Utah,
Draft; EPA; April 23, 1990.
2. Superfund Program Proposed Plan, Sharon Steel/Midvale Tailings Site, Midvale, Utah; EPA
Region Vifi; July 1989.
3. Final Feasibility Study Report for the Mill Site Operable Unit 1 of the Sharon Steel/Midvale
Tailings Site, Midvale, Utah, and Appendices; Camp, Dresser & McKee; July 14, 1989.
4. Declaration for Record of Decision - Sharon Steel (Operable Unit 2) Residential Soils, Midvale,
Utah; EPA Region VIII and the Utah Department of Health; September 24, 1990.
5. Meeting Notes Concerning Sharon Steel/Midvale Tailings Site; From Laurie Lamb, SAIC, to
Sam Vance, EPA Region VIII; March 26, 1991.
6. Report of the Preliminary Assessment/Site Inspection of Sharon Steel Corp.; Prepared for EPA
Region VIII by Pat lanni, Ecology and Environment, Field Investigation Team, March, 15,
1983.
7. Potential Hazardous Waste Site Identification and Preliminary Assessment, Sharon Steel
Corporation; Prepared for EPA Region VIII by Ecology and Environment, Field Investigation
Team, March 14, 1983.
8. Proposed Plan for the Mill Site, Operable Unit No. 1, Sharon Steel Site, Midvale, Utah; EPA
Region VIII; October 1990.
9. Remedial Investigation Addendum for Sharon Steel/Midvale Tailings Site, Midvale, Utah, 1989-
1990 Ground-water/Geochemistry Data Report; Prepared for EPA by Camp, Dresser & McKee;
Undated.
10. Feasibility Study Operable Unit I, Mill and Tailings Site, Sharon Steel/Midvale Tailings Site,
Midvale, Utah, Volumes I and II; Prepared for EPA by Camp, Dresser & McKee; October
1990.
17
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Sharon Steel/Midvale Tailings Site Mining Waste NPL Site Summary Report
Reference 1
Excerpts From Interim Baseline Risk Assessment
for the Sharon SteelIMidvale Tailings Site, Midvale, Utah, Draft;
EPA; April 23, 1990
-------
INTERIM BASELINE RISK ASSESSMENT
FOR THE
SHARON STEEL/MIDVALE TAILINGS SITE
MIDVALE, UTAH
DRAFT
April 23, 1990
-------
Steel/Midvale Tailings Study Area prepared by Camp Dresser & McKee (1988)
Information obtained from other sources is referenced accordingly
The Sharon Scee]./Midvale Tailings study area is located in the town of
Midvale, Utah, approximately 12 miles south of Salt Lake City (Figure 1-1)
The study area includes the region from which samples were collected during
the Remedial Investigation (RI). The mill site is defined as the tailings
source area, including the tailings piles and mill buildings. It is bordered
by 7800 South Street on the north, South Holden Street and Le ox Street on
the northeast, South Main Street on the southeast, and the Jordan River on the
west and south (Figure 1-2). The western border does extend, however, to
include a smaller tailings pile on the western side of the Jordan River.
The site comprises the milling portion of a former milling and smelting
operation originally owned and operated by U.S. Smelting (later U.S. Smelting,
Refining and Mining Company) and is approximately 260 acres in size. The
milling facility operated for a period of about 61 years (from 1910 to l97l);
the smelter, located to the north of 7800 South Street, closed in 1958. The
original operations involved receiving lead, copper, and zinc ores; extracting
the sulfide concentrates of these metals in the milling operation; and
smelting these concentrates to extract the metals in purer form. The facility
also operated as a custom mill, receiving ores from many clients and
concentrating and extracting a variety of metals to their specifications. The
wastes from the milling operations were disposed of in unconsolidated tailings
piles at the present site. The mill site includes several mill buildings and
approximately 12-14 million cubic yards of tailings in uncovered piles up :o
50 feet de.p in places.
An envirot sntal health problem was first suspected in June 1982 (UDOH l982a),
when the Utah Stats D.psrtment of Health was notified that citizens were
gathering windblown tailings along the 7800 South Street right-of-way and
utilizing them in s*ndbox.s, gardens, and similar areas. The Utah Department
of Health analyzed a sample of the sand, and found that it contained 4,000
mg/kg of lead. In August 1982, the State of Utah sampled the windblown
1-4
-------
Figure 1-i
SHARON STEEL/MIDVALE TAILINGS sr
MIOVALE, UTAH
Sit• LocatIon
Camo O,.ss.r & PACKIS Inc Dy____
CDN Oat.—
N•rTh
SALT LAKE CITY
I
0 1
N
2 1
Sca*
Mfl•s
3-5
I
-------
-c
500
250 0
1000
eee
CONTOUR INTERVAL — 250 mg/kg SH?RON S1EEi/MIc VALE 1AILII46S SITi
I sbVAL SO%LS
Pb O•2 INCHES
(mg/kg)
CA O IO0c I 0 U Oic.
NC.
2 4
-------
The quality of the residential soils data is discussed in detail in CDM
(1990) Data quality relative to sample splits, blanks, ririseates, and
performance evaluation samples appears to be excellent
2.1.3 Surface Water and Sediments
Water samples from the Jordan River were collected both upstream and
downstream of the mill site as described in the Final Draft RI (CDM 1988) In
the EA, Table 2-9 summarizes the concentrations of dissolved metals at these
two locations. Table 2-10 presents the results of samples taken from surface
water bodies other than the Jordan River. Table 2-11 presents the results of
sediment analyses for both the Jordan River and other surface water bodies
2.1.4 Geochemistry Study
A limited geochemistry study of the soil and waste materials associated with
the Sharon Steel/Midvale Tailings site was conducted by Drexler (1989). This
study examined 15 samples including two tailings, one slag, one bag ouse dust,
nine soil, and one dross samples. Some of these samples are more associated
with the adjacent Midvale Slag site. The methodology used was electron
microprobe utilizing energy dispersive, wave length dispersive, and
backscatter detectors. Details including quality assurance (quality control)
may be found in Drexler (1989).
The results of four of these analyses are reported in Table 2-3. In general
there is considerable variability in the sample results. Both the tailings
and slag sites appear to have contributed to the soil lead. The results also
indicate that other sources of lead (e.g., automobile exhaust or paint) are
unlikely to b. significant contributors to the soil lead burden. The wide
variability and matrix complexity of lead associations suggests the potential
for a wids variation in bioavailability and, potentially, toxicity.
2-9
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4.0 EXPOSUP.E ASSESS) NT
This section addresses the potential pathways by which human populations could
be e’:posed to contaminants at, or originating from, the Sharon Steel/Midva].e
Tailings site and study area In identifying potential pathways of exposure,
both current and likely future land-use of the site and surrounding area are
cons :dered.
Important steps in identifying exposure pathways are to characterize the site
setting and consider mechanisms of migration for the selected chemicals in the
environment. Accordingly, Section 4.1 presents a brief summary of information
characterizing the site study area including hydrogeology, hydrology, soils
and climatology. Mechanisms of migration were discussed in the EA and Section
3 of the Draft Final RI (CDM 1988), and are also briefly suarized here in
Section 4.1. In Section 4.2, demographic information for the Midvale area is
presented, potential exposure pathways are discussed, and those selected for
detailed evaluation are identified. In Section 4.3, chemical concentrations
at potential exposure points are provided and human exposure estimates for the
selected pathways are presented. Section 4.4 siimm rizes uncertainties in the
Exposure Assessment.
4.1 CRARACTEB.IZATION OF SITE SETTING
The following sections provide background information on hydrogeology,
hydrology, soils, and climatology of the site .study area. This information
was also provided in the Draft Final RI. In addition, a brief suary of key
mechanisms of migration at the site is provided in Section 4.1.5.
4.1 1 Sits Bydrogso]ogy
The information in this section may be revised pending receipt of the results
of current groundwater monitoring studies.
4-1
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The Sharon Steel/Midvale Tailings study area is located in the Jordan River
Valley, which is a flat, sedinient-filled valley separated by fault-block
mountains typical of the Basin and Range physiographic region The valley s
bounded on the east by the Wasatch Mountains, on the west by the Oquir:h
Mountains, on the north by the Great Salt Lake, and on the south by the
Transverse Mountains. The valley has been filled with lacuscririe sediments
deposited in ancient Lake Bonneville, interlayered with coalescing alluvial
fans derived from the adjoining mountains. Sediments are estimated to exceed
2,000 feet in thickness.
The groundwater system in the Jordan Valley consists primarily of a shallow
uriconfined aquifer overlying a deep confined aquifer. In addition, a
localized shallow perched zone has been identified above the unconfined
aquifer.
Regional and local studies of groundwater movement have been conducted and
provide information pertinent to the site (Nely et al. 1971, Seiler and
Waddell 1984, Earth Fax Engineering 1987). Section 7 of the Final Draft RI
(CDM 1988) presents a detailed discussion of the site hydrogeology. Recently,
however, a very extensive additional ground water investigation has occurred
at the site which will allow a much more definitive description of site-
specific hydrogeological conditions. Reports detailing the methods and
results of this investigation and potential risks associated with ground water
will be available in the Fall of September 1990. The degree and extent of
interconnection between the two aquifers at the site will also be discussed in
the groundwater report.
Both the deep and shallow aquifers are a source of drinking water for Sal:
Lake County. Municipal supply wells operated by Murray, Midva.le, Sand City.
and the Salt Lake Water Conservancy District are located within three miles of
the Sharon Steel/Midvale Tailings study area. The direction of groundwater
flow for the deep confined aquifer is believed to be westerly, toward the
Jordan River.
4-2
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TABLE 2-4
PARTICLE SIZE DISTRIBUTION DATA FROM TAILINGS SAMPLES
Sample
Percent lO urn
Percent <10 urn
Sample A:
Total Mass
73.1
26.9
lead
29.0
71.0
zinc
52.4
47.6
copper
38.9
61.1
Sample 8:
Total Mass
77.6
22.4
lead
28.6
71.4
zinc
47.4
52.6
copper
31.5
68.5
Sample C:
Total Mass
84.0
16.0
lead
42.0
58.0
zinc
57.0
43.0
copper
62.6
37.4
Sample D:
Total Mass
82.1
17.9
lead
38.0
62.0
zinc
48.1
51.9
copper
54.7
45.3
* Source: Montgomery (1989b).
2-12
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that there were two distinct populations of soils data (CDM 1988) The
population with the lower mean metal concentrations was considered to
represent local background conditions (CDM 1988) The results for the metals
of concern in soil for this SPA are summarized in Table 2-5 Some of the
values estimated to represent local background conditions in Table 2-5 are
slightly greater than the values for U.S. background soils summarized in Table
5-1 in the Final Draft RI (CDM 1988). It is likely, however, that histor ca1
mineral processing and smelting activities in the valley have contributed to a
general increase in local background metal concentrations in soils.
Alternatively, local background values could be representative of lithologic
differences in the sediments deposited in the study area. Analysis of the
over 180 soil sample results in the Final Draft RI generally indicated that
the concentration separating local background soil samples from contaminated
soil samples is approximately 150 mg/kg for lead (CDM 1988). For arsenic, the
data indicated an upper limit of approximately 20 mg/kg for background
concentrations (CDM 1988).
2.3 S A&Y OF CHE(ICALS OF CONCERN
Results of the previous EA, data quality considerations, and estimated
background soil concentrations support the focus of this assessment on
arsenic, ca ium, and lead as the primary chemicals of concern.
- 2-13
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4.1.2 Site Hydrology
Portions of the Sharon Steel/Midvale Tailings mill site, including most of the
tailings piles, lie in the floodplain of the Jordan River. The Jordan River
flows northerly from Utah Lake to the Great Salt Lake. Historically, the
Jordan River flowed through the mill site, but was relocated to the west of
the site to facilitate tailings deposition. The eastern part of the site lies
on a terrace above the floodplain. The tailings piles currently form an
emban1 ent on the east side of the Jordan River. The tailings lack any
provisions for containment or diversion of surface water rurion or runoff.
The Jordan River, where it passes the mill site, is classified by the state of
Utah for the following uses: recreation, excluding swi ing (Class 28); cold
water game fish (Class 2A); and agriculture (Class 4). Ten irrigation intakes
from the Jordan River lie within three miles of the site and irrigate
approximately 160 acres. Use classifications upstream and downstream of the
mill site differ from the classifications of the river where it passes the
site. The site hydrology is discussed in more detail in Section 6 of the
Draft RI Report (CDII 1988).
4.1.3 Soils
The soils in the Midvale area occur on three different land features with the
soils on each feature very closely related. The soils located on each feature
are markedly different from the soils on the other two features. The first
feature is the floodplath which is composed of Bramvell, Chipman, and Magna
soils, and mixed alluvial land and sandy alluvial land units. The floodplain
is the area along the Jordan River between the North Jordan canal and Galena
canal (Figure 2-2). The second feature is composed of the terraces from the
Great Salt Laire/Lak. Bonneville system, with Taylorsvil]e, Hulifield, Kidman,
Welby, Parleys, and Harrisville soils. The third feature is made up of
artifacts of the mining industry, namely tailings di.ps and man-made fill.
4-3
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Residential units in Midvale are on terrace and mining industry artifacts
complete description of the floodplain and terrace soils and the mining
industry artifacts (e.g , old equipment) is presented in Section 5 of the
Final Draft RI Report (CDM 1988) During the recent off-site residential
soils investigation, a narrow “black layer” was identified in some of the
residential soil samples The potential origin of this layer is discussed in
detail in the off-site soils report (CDM 1990).
4.1.4 Climatology
The site vicinity is generally classified as mid-latitude semi-arid,
indicating an area of high suer temperatures, cold winters, and sparse
rainfall. Mean maximum temperatures for the years 1951-1980 range from 42
degrees Fahrenheit (‘F) in January to 93 ’F in July; mean minimum temperatures
are 22F in January and 66 ’F in July. The mean number of days with air
temperatures at or lower than freezing is approximately 65 days/year (NOAA
1988).
The mean annual precipitation for the years 1951-1980 in the vicinity is 22.5
inches per year, with highest precipitation in April (3.0 inches) and lowest
precipitation in July (0.7 inches).
The climate along the Wasatch Front is strongly influenced by elevation and
topography. Wind flows, in particular, are influenced by surrounding terrain
Site-specific meteorological data collected during the RI showed that the
predomi-riant wind directions were from the south (39 percent) and south-
southeast (11 percent).
4.1.5 S m..’y of Xecha”isma of Migration
As described in the EA, a number of inorganic contaminants are present at
elevated concentrations in the soils and mill tailings, air, ground water, and
surface water or sediments at the Sharon Steel/Midvale Tailings study area.
4-4
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4.2.1 Site Demographics
The City of Midval.e is located adjacent to the mill site and to the east
Producing agricultural lands are located across the Jordan River to the west
of the mill site. Occupied residential and commercial areas lie immediately
adjacent to the mill site on the east
For the purposes of this project, demographic statistics were obtained for
three areas surrounding the site (CAd 1990): within 2 miles, for the City of
Midvale, and for Census Tract 1124.02 (see Figure 4-1 for delineation of these
areas). The results of the survey are provided in Tables 4-1 through 4-3. As
can be seen from these tables, the 1990 estimated population for the three
areas is 43,911, 12,085, and 6,716, respectively. The average per capita
income for the three areas is reported to be $9,849, $10,151, and $10,730,
respectively. The national average per capita income in the U.S. is $12,121
(1989 estimate) (CACI 1990). The age distributions indicate that from 36-39%
of these populations are from 0-16 years of age, 48-49% are from 17-54 years,
and from 11-16% are over 54 years. Individuals who are members of low
socioeconomic groups (i.e., below average per capita income) are more likely
to be subject to nutritional deficiencies and have less access to health care
delivery systems. The large proportion of children in the population
indicates that a high degree of exposure associated with childhood behavior
patterns such as mouthing of objects may also be experienced by the Midvale
population. Taken together, the low income and large proportion of children
constitute a sensitive subgroup which should be considered in setting remedial
goals at the sire.
4.2.2 Potential. Exposure Pathways Under Current Use Conditions
Sampling data generated during the RI (CDM 1988) and subsequent efforts (CDM
1990) suggest that there is a potential for exposures to occur through contact
with contaminated soil, air, groundwater and surface water under current use
conditions of the mill site and surrounding area. The primary receptors of
4-7
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/.l. L
I
City
of
Midvale
-
1
FIGURE 44
D arsp ic Ar ss E iDed
for the Shar Si Site
H 114. i,,:,
/ .-i
// ,/y
Tract
1124.02
_r,_. 1 1 1 1
P •‘1,
/
---V
,
./31r
I
1 MILE
SCALE
— - City of Mldval Boundary
a Csnsus Tram Boundary
a 2 MIls Radius Boundary
-------
5.0 RISK CRAR.ACTERIZATION
This section presents quantitative risk estimates for the exposure pathways
and chemicals examined in this assessment. To calculate risks, the chronic
daily intakes estimated for each chemical of potential concern were combined
with health effects criteria (RfDs and cancer slope factors). In the case of
lead, the blood lead levels estimated in Section 4 were compared to blood lead
levels considered to be of concern to human health. In Section 5.1 below,
risks associated with current land and site use conditions are presented for
arsenic and cadmium. In Section 5.2, risks associated with future site and
land use conditions are presented, also for arsenic and cadmium. Section 5.3
presents an evaluation of the potential for adverse effects from lead
exposure, both under current and future land use conditions. In addition,
Section 5.4 presents a review of recent risk characterization efforts at
similar sites. Section 5.5 discusses uncertainties affecting the risk
characterization. Section 5.6 suarizes the risk characterization for the
Sharon Steel,/Midvale Tailings site.
To evaluate risks associated with exposure to carcinogens (e.g., arsenic), the
excess lifetime cancer risk was calculated by multiplying the CDI by the slope
factor as follows:
Excess lifetime cancer risk — CDI x CSF
where
CDI chronic daily intake of chemfcal (mg/kg/day), and
CSF cancer slope factor for chemical (mg/kg/dayY 1 .
Potential rick, for noncarcinogens with the exception of lead are presented as
the ratio of rh. CDI to the reference dose (CDI:R.fD). Ratios that are greater
than one can indicat. the potential for adverse effects to occur, ratios less
than one indicate that adverse effects are unlikely to occur.
In accordance with USEPA’s guidelines for evaluating the potential toxicity of
complex mixtures (USEPA 1986b), the excess lifetime cancer risks and CDI :R.fD
5 -1
-------
ratios are each summed. The sum of the CDI:RfD ratios is referred to as the
hazard index. Values greater than one indicate that adverse effects could
occur. In this assessment, however, the CDI:RfD ratios for arsenic and
cadmium were not combined because these two chemicals affect different target
organs (see Table 3-2). Specifically, arsenic exposure may result in
hyperpi entation and keratosis of the skin, as well as in adverse effects to
the central nervous system. Cadmium exposure can result in adverse effects to
the kidney, hypertension and iunosuppression. The CDI:RfD ratios were added
across exposure pathways for each of these chemicals separately.
5.1 POTENTIAL RISES UNDER CURRENT LAND USE CONDITIONS
Table 5-]. presents the results of the quantitative risk assessment for the
exposure pathways evaluated under current use conditions. For all pathways
except inhalation, arsenic is the only carcinogenic chemical evaluated. For
the inhalation pathway, both arsenic and cadmium are carcinogenic. The excess
upperbound lifetime cancer risks for all exposure pathi ays combined is 5xl0 ,
primarily due to exposure to arsenic from ingestion of tailings in sandboxes
and ingestion of indoor dust. It should be noted that public information
efforts by the State of Utah and USEPA have generally eliminated the route of
exposure involving tailings ingestion from sandboxes. 1
Table 5-2 s’immarizes the CDI:RfD ratios for the same exposure pathways (except
inhalation for which both arsenic and cadmium are carcinogenic). Also shown
is the overall hazard index for arsenic and cadmium (treated separately)
across -exposure pathways. As shown in this table, the hazard index for
arsenic exceeds one, pr{ *rily due to exposure via tailings ingestion and
indoor dust ingestion. For cadmium, the hazard index also exceeds one, due
predominantly to exposure via indoor dust ingestion and soil ingestion.
1 Symonik, D. Utah Depar ent of Health. Personal counication. April
10, 1990.
5-2
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TABLE 5-4
POTENTIAL FOR ADVERSE NONCARCINOGENIC EFFECTS AT THE
SHARON STEEL/HIDVAI.E TAILINGS SITE
FUTURE SITE USE
Exposure Pathway/
Chenical
Chronic Daily
Intake
(mg/kg/day)
Reference Dose
(mg/kg/day)
(Uncertainty
Factor] (a)
CDI:RfD
Ratio
Tailings Ingestion
Arsenic
Ca uiij ii
1.12E-O5
1.82E-06
1 OOE—03 [ 1]
I.OOE-03 (10]
1E—02
ZE- 03
Dust Ingestion
Arsenic
Cadoiimi
3.22E-03
2. SOE— 03
1.OOE—03 [ 1]
1.OOE-03 (10]
3E+0O
2E.O0
Produce Ingestion
Arsenic
Ca n iiei
5.45E—04
1.68E—03
I.OOE—03 [ 1]
1.OOE—03 (10)
5E-0I
ZE.OO
Total Hazard Index
Arsenic
Ca a1im i
———
-——
———
--—
4E+O0
4E.00
(a)
Uncertainty factor, used to develop reference doses generally consist of
ltiples of ten (10). wIth each factor representing a specific area of
uncertainty in the available data. Standard uncertainty factors include a
factor of 10 to account for variation In sensitivity ng m ers of the
hi an population Modifying factors may also be applied at the discretion
of the revismer to cover other uncertainties in the data.
5-7
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Table 4-18 suarizes the calculated blood lead levels under both current and
future use conditions for two combinations of exposure pathways, all of them
combined and all except sandbox tailings ingestion and homegrown produce
ingestion combined. As shown in this table, blood lead levels exceed 30
ug/dL, the highest value that can be reliably predicted using USEPA’s model
(i e. , the relationship between lead intake and blood lead levels is nonlinear
at blood lead levels above 30 ug/di). Under current use conditions, this was
the case for children ass ed to ingest tailings in sandboxes and homegrown
produce as veil as not, except in the <500 mg/kg residential soil lead
concentration band for a child assumed not to ingest sandbox tailings or
homegrown produce (for which a blood lead level of 24 ug/dL was predicted).
Table 5-5 s1 1mInRrizes the input parameters used to calculate lead intakes and
ultimately blood lead levels.
Based on the estimated blood lead levels, adverse effects from exposure to
lead could potentially occur to young children under both current and future
use conditions at the Sharon Steel site. These effects in children could vary
from blood disorders through cognitive dysfunction and reduced growth.
Although blood lead levels in adults were not specifically ca]culated, it is
also possible that exposures via the same pathways could potentially result in
adverse effects; in adults these effects may be manifested as hypertension.
5.4 RISK CHARACTERIZATION EFTOR.TS AT SIMILAR SITES
To put the results of this assessment, spec.ifically with respect to lead, into
better perspective, information available from studies conducted at other
mining/smelting site in the western United States can be useful. There are
several studies that have been conducted in an attempt to relate blood lead
and envirQLaental lead levels. A review of all of these is beyond the scope
of this siug].e eport, however, a few are discussed here to provide some
information on the types of approaches that have been used and results
observed. Studies at the Midvale site (Boernschein et al. 1989), the Helena
site in Montana (MDHES 1986), the Bunker Hill site in Idaho (USEPA l988c), and
5-8
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6 .3 POSURE ASSESSMENT
Potential pathways by which humans could be exposed to arsenic, cadmium, and
lead at or originating from the site under current or future use conditions
were identified and selected for evaluation The exposure assess enr was
performed in accordance with concepts on exposure advanced in the NC? (USEPA
l990a). The exposure pathways selected for evaluation in the ZRA were
follows:
Current Use Conditions
- direct contact with and incidental ingestion of site tailings in
sandboxes by children;
- direct contact with and incidental ingestion of residential area
soils by an individual assumed to be exposed both as a child and
subsequently as an adult (e.g., a gardener);
- inhalation of windblown particulates from the site by nearby
residents; and
• ingestion of home-grown produce by nearby residents.
uture Use Conditions
- direct contact and incidental ingestion of site soils by an on-site
resident assumed to be exposed both as a child and an adult;
- inhalation of windblown particulates from the site by an on-site
resident; and
- ingestion of home-grown produce by an on-site resident.
To evaluate exposures for each pathway, concentrations to which individuals
might be exposed were calculated based directly on site-specific sampling data
or were predicted using environmental models. For the inhalation pathway,
emission and dispersion models were used to estimate air concentrations For
the homegrown produce ingestion pathway, particle deposition and plant uptake
models were used to predict concentrations in vegetables. The approach used
to estimats these concentrations (and to calculate potential human exposures)
followed recent USEPA guidance for Superfund site risk assessments, in which
USEPA states that the baseline risk assessment should evaluate •reasonable
maximum exposures” (RHE) expected to occur under both current and future land
use conditions. USEPA notes that “the intent of the RH! is to estimate a
6-3
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Sharon SteellMidvale Tailings Site Mining Waste NPL Site Summary Report
Reference 2
Excerpts From Superfund Program Proposed Plan,
Sharon SteelfMidvale Tailings Site, Midvale, Utah;
EPA Region VIII; July 1989
-------
EPA ANNOUNCES PROPOSED PLAN
This Proposed Plan identifies the preferred option to remedy the threat posed by contaminated tailings, Soil, arid
ground waler at the Sharon SteeL,),fidvaJe Tailings Superfund site. This Plan also incfudes summaries of the other
alternatives that were analyzed for this site. This document is issued by the U.S. Envtronm.rnaj Protection Agency
(EPA). the lead agency for site activities. EPA will select a final remedy for the site only after the public comment pe•
nod has ended and the information submitted during this time has been reviewed.
The EPA is using this Proposed Plan as part of its public participation responsibmtjes under sections 104 and 117(a)
of the Comprehensive Envirorimentaj Response, Con’çensatiori and Liability Act (CERCLA), as amended by the
Superfund Amendments and Reauthonzat,on Act (SARA). This document surrr Iarlaes hdormalion which can be
found in greater detail in the Remedial Investigation and Feasibility Study (Rl/FS) reports and other documents
contained in the administrative record file for this site. The EPA encourages the public to review these other docu-
ments for a more comprehensive understanding of the site and Superfund activities that have been conducted there
The administrative record file, which contains the information upon which the selection of the response action will be
based, is available at the following locations:
Ruth Vine Tyler Lbrary and U. S. EPA Ubraiy
315 Wood Street EPA- Region VIII
Midvale, Utah 999 19th Street. Suite 500
Hours: Mon. Thuri, 9:00am - 900pm Denver, Colorado 10202
Fn - Sat, 900am 530pm 1.(800) 759.4372, ext. 1414
Hours: Mon. Frf, 1:00am 430pm
The EPA may modify the preferred alternative, select another response action presented in this Plan and the RI/FS
Report, or select a more appropriate alternative based on new urdorrnation or public comments. Therefore, the public
is encouraged to review and comment on $9 the alternatives identified here, as wet as to provide any information not
previously identified. More delailed Wdomiatlon on an the aftemaftvu can be found in the FS Report.
Superfund Program U.S. EPA
Proposed Plan Region VIII
Sharon Steel/Midvale Tailings Site
Midvale, Utah July 1989
MARK YOUR CALENDAR
July 14-August 21, 1919:
Public co4wnerit pitied on remedies to control contaminated sea amid taitings at the Sharon S*eeI4.4idvale Tailings
S erfund sle.
August 17. 1919:
Public meeting at the Midvale Bowery. M vaIe City Path, 327 East 6th Avere e, M vaIe, Utah at 700 p
Septervter3O, 1989
Record of Decision, which selects final remedial alternative for the Mill site.
- /
I
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SiTE BACKGROUND
The Sharon SsseVMldvsIe T rigs sle
io lecated in M vale, Utah, gh z1 -
inately 12 mIss south of Salt L*e Cly
arid west of Interstate 15. Tbs 2SOws
as used by an ore refining
coIT aflyfrom 1905 to 1971. Generally.
the tr ale le bordered by 7800 South
Streeton the r rth,by Main Street on
the east arid the Jordan River on the
west and south (See Fi jre Isle loca-
t n map).
Eight buildings are located on the mill
5* 1 includIng three small olf es, a
bunichouse, $ machine storage shed,
and three mill buildings. A 22acre
wetland arid several small ponds are
also located on the mill ale. During
miLling activ*ies at the site, metals such
as lead, pper . and zlrc were remevsd
from crushed ore. Tailings remaining
after metals had been extracted from
the ore were deposled on the s Ic. EPA
estimates that 14
million cubic yards of tailings currently
remain on the 5* 5.
An environmental health problem was
f si suspected in 1982 when the Utah
State Department of Health learned that
• Gather Irdormatiori needed to develop remedial
o ons.
To determine N the ale caused a cor*arninatlon problem,
EPA reviewed previous studies conducted near the mill
sitS. EPA also collected samples from the taings piles,
soil, ground water, suu1 water, sediments, and air in
Vhs dy area. An Endangerment Assessment (LA) was
prs edby EPA to determine rWcsto t aman health and
the environment resulting from exposure to she contami-
.ft
The LA revealed that lead and arsenic contained In on•
site tailings or windblown tailings dI s$ may threaten
human health I the tailings tui eives or tailings di st
are ingested. EPA o concluded that humans may be
e osed to coiWninerls by eating vegst les grown
directly on the tailings or in contaminated sot The
greatest ri s c lies in ewailewing tailings and eating leafy
and roct crops grown in sols contaminated with the
tailings. Children ate especially at riok because during
play I le possible for them to come W*o contact with dirt
that may be contaminated.
+
d*Izens were
Figure 1 SitS Location Map.
using windblown tailings from 7800 South Street in sand
boxes arid gardens. The State analyzed a sample of the
sand and found that I contained unsate levels of lead.
Samples from the wlnXlown t ngs from locations
along 7800 South Street showed elevated concentra
lions of arsenic, cadmlum, chromium, copper . lead, arid
zW .
Several sançlngefiorts revsaledthat cof*winateds*
aW and ground water were esira. EPA proposed the
mlH ili for listing on is lonai Priorities L (P4PLJ W i
1984. The NPLianatIor ldeIatofsllssthatareeIgible
for Investigation arid dear under the Supeøund p
EPA ’s Remedial Wwes*igatlon at the M I sic began In
My 1987 and cor*lr*asd thmu ’i lune 1988. The sludy
was designed to:
• lderdiy the nature arid extent c i contamination
related tothe ale;
• Determine whither current or future contamination
from the site may threatsn human health or the
environment; and
2
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Sharon Steel/Midvale Tailings Site Mining Waste NPL Site Summary Report
Reference 3
Excerpts From Final Feasibility Study Report
for the Mill Site Operable Unit 1 of the Sharon SteellMidvale Tailings Site,
Midvale, Utah, and Appendices; Camp, Dresser & McKee;
July 14, 1989
-------
I
‘I
FEASIBILITY STUDY REPORT
POE T IE
MILl. SITE OPERAILE UNIT 01
OP TIE
SIARON STEEL/MIDVALE TAILINGS SITE
NIDVALE, UTAR
JULY 14, 1989
EPA Contract No.: 003-8140
Docuasnt Control No. $ 7760-003—PS— edT
Prepared fort
U.S. Ioviron..ntal Protection Agency
999 18th Strait
Denver, Colorado 80202
Prepared by:
Cup Druser & NcR.. Inc.
2300 15th Street, SuIte 400
Denver, Colorado 80202
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1.0 INTRODUCTIOI4
July 1987, EPA initiated the Eseedial Investigation/Feasibility Study
(El/PS) for the Sharon Ste.1./Midvaie Tailings site. A Final Draft of the
pj report coapleted in June 1988 (CDIi 1988b) detereined that past silling
operations on the site generated approxisately 14 sillion cubic yards of
tailings vhieb have contaainated local soils and ground vater.
To ensure that re.ediation proceeds in a tiasly aanner, EPA has divided the
,ite into tvo operable enits. An operable unit is a discrete portion of an
entire site, vhich is addressed separately ira. other units. Operable Unit
. is the sill site vhich is the prisary source of contaaination.
operable Unit No is adjacent to the .111 sits and includes residential
areas and other areas ir.quently used by the public vhich have been
contasinated by tailings. This PS addresses only Operable Unit ., the
aill site. The focus is on rs.ediating the source of contasination. The
VS f or Operable Unit Tvo viii be co.pleted foi]oving signing of the Record
of Decision (ROD) on Operable Unit One; the ROD is nov scheduled for fall
1989.
This section includes a brief discussion of the purpose of the P1/PS
(Section 1.1), a s’ ry of activities co.plsted during the Ii (Section
1.2), a site description including the history of the sits (Section 1.3), a
s ary of the nature and extent of contasination (Section 1.4) and an
outline of the PS process (Section 1.3).
1.1 PURPOSE
EPA conducted the Sharon Steel/Midvale Tailings LI to deternine the nature
and general extent of the release of hazardous substances; the extent to
bich th. release or threat of release eny pou a threat to hur health
and the sovironsent; the extent to vhich sources can be adequately
identified; and to gather sufficient inforastion to dsteraioe the necessity
for resedial action.
1—1
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me Endangerment Usessnent (BA), coapleted as part of the L I, deterained
that under current lend use conditions, carcinogenic end toxic
non—carcinogenic) risks exist for children and adults in the residential
eu adjacent to the ciii site as a result of exposure to arsenic (10 —
10_S carcinogenic risk) and lead. Action levels appropriate for future
nd use scenarios at the mill site, including residential development end
light industrial use, are developed in this PS. Potential risks to
vironmental receptors are discussed qualitatively in the LA. The risks
juclude phytotoxicity and adverse effects to viidlife. These findings are
discussed in sore detail in Section 1.4. Arsenic and lead are the primary
contaminants addressed in the PS.
The PS evaluates remedial action alternatives based on the data in the RI
report and on supplemental investigations subsequent to the RI. £ su ry
of RI activities is presented in Section 1.2 and th. supplemental
jnvestigationi are described in Section 1.3.2. The purpose of the PS for
the Sharon Steel/Plidvale Tailings site is to develop a list of
alternatives (1) that are protective of human health and the environment,
(2) that attain Federal and State requirements that are applicable or
relevant and appropriate (ARAP.s), (3) that are cost —ti fective, (4) that
utilize permanent solutions and alternative treatment technologies or
resource recovery technologies, to the maxi ua extent prac ticable, and (5)
that satisfy consideration of the preference for remedies vith treatment.
The PS his been prepared in eccordanee vith the provisions of the Superfund
Amendments and Reauthorization Act of 1986 (SARA), CL (42 U.S.C. 9601,
et .) end the National Contingency Plan (NCP) (November 20, 1985), and
the proposed NC? (December 21, 1988). The folioving EPA docuse ts have
also been folloved: Guidance on Feasibility Studies Under CLA (EPA
1983) and Guidance for Remedial Investigations and Feasibility Studies
der CL& (October 1988).
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Based on the evaluation of the alternatives identified in the PS, EPA has
developed a Proposed Plan for resediating the sill site. The public ii
encouraged to rsviev the PS and the Proposed Plan and to jubsit coenta to
EPA. A glossary of teras has been included U Appendix A to uaist the
reader in interpreting these docusents. Based on the PS and the co ents
received by the public, EPA viii develop a Final Plan for inclusion in the
Record of Decision (ROD).
1.2 StflO ARY or B! ACLL’fITIES
Field investigatiOns vere perforsed f roe July 1987 through Decesber 1987
and included the foliovirig activities
o Site surveying and sapping
o Installation of nine sonitoring veils on the sill sits
o Soil, tailings, and sill building siapling on the sill ite
o Soil saspling in residential and agricultural areas adjacent to the
sill sits
o Surface vater flov uessureaentl
o Surface vater and sedisent saspling
o Ground vatsr level onitoriflg
o Ground vater saapiing
o Air sonitoring for three onths at four air quality stations and for
six .ontha at tvo seteorological stations
The field setivitiei vera conducted utilizing the enst recent EPA R I
guidance vhich required the preparation of the folloving docaefltat
Final York Plan for RI/PS, Sharon StesllMidv$le Tailings Site, Hidvale,
Utah (CON 1987a).
Final Bealth and Safety Plan, Sharon Steel/Midvale Tailings RI/PS,
Midvale, Utah (CON 1987b).
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Final Sampling and Analysis Plan, Sharon Steel/Nidvale Tailings RI/PS
(CDN 198Th).
Final Quality Assurance Project Plan, Sharon Steel/Nidvale Tailings
RI/FS (CDM 1987d).
Final Community Relations Plan, Sharon Steel/Midvale Tailings Site,
Hidvale, Utah (cDfl 1988a).
The data obtained during the field activities vera compiled and summarized
in the ‘Final Draft Remedial Investigation Report, Sharon Steel/Midvale
Tailings Site, Midvale, Utah’ (CVN, 1988b), vbich is used as the basis for
conducting the PSs for both operable units.
In total, 531 samples vere collected f roe the Sharon Steel/Nidvale Tailings
study area and analyzed by the Contract Laboratory Program (CL ?). These
samples included 15 surface vater sasples, 19 ground vater samples, 97
tailings samples (44 surf icial, 53 subsurface) from the mill site, 12
stream sediment samples, and 229 air samples. The results are of varyin
data quality in terms of Quality Assurance/Quality Control, and also
address Operable Unit 2, off-site residential areas. In addition, field
observations/measurements and screening analyses of 182 soil samples vere
performed. These included 34 soil samples fro. the mill site and 125 soil
samples from residential and agricultural area* adjacent to the mill site.
All sampling and analytical york v conducted using methods approved by
EPA Region VIII.
1.3 SITE DESCRIPTION
1.3.1 SITE LOCATION AND DESCRIPTION
/
The Sharon Steel/Midvale Tailings site is located in Midvale, Utah,
approximately 12 miles south of Salt Lake City (Figure 1—1) and vest of
Interstate 15. Th. approximate study area is depicted on Figure 1—2 and
includes the tailings, agricultural land to the vest and south, the
•outhvest portion of the Nidvale counity, and vetlands located to the
south and seat. The mill site area, vhich includes the tailings, .111
1-4
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Sit. Location
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buildings, and the vetlands, is located south of 7800 South Street, east of
the Jordan River and vest of Nain Street. The mill site boundary, as
ahovn in Figure 1—2, vas used as the site boundary vben the site vms
nominated for placement on the NPL. Based on an estimated extent of
contamination, 81 investigations vere conducted vithin the study area shovn
in Figure 1—2. Figure 1—3 illustrates the locations of ground vater,
surface vater, and sediment sampling on the mill site.
To provide for timely selection of a remedy on at least one portion of the
site, the study area vas divided into tvo operable units, as noted
previously. The mill site area comprises the original site boundary and is
Operable Unit One (OU1). Operable Unit Tvo (0U2), hereafter referred to as
off—mill site, encompasses the residential and high public use areas
adjacent to the mill site. Its boundaries are subject to revision based on
additional sampling vbich viii be conducted as part of the FS for 0U2. As
illustrated in Figure 1—2, the entire study area covers approximately 830
acres, of vhich 260 acres comprise the mill site. Approximately 200 acres
comprise the residential and high public use areas adjacent to the mill
site. The remaining 370 acres comprise agricultural lands to the vest, and
light industrial and co..ercial lands to the south and east.
The site can be divided into tvo operable units, because the location and
use of each pose varying risks to human health and th. environment. OUl
has been defined as a ‘source area and public access is restricted by a
fence, security personnel, and locked gates; vherw 0U2 has been defined
as an ‘impacted area’, and includes the co unity and other areas
frequently used by the public.
1.3.2 SITE BISTORT
The Sharon Steel/Nidvale Tailings mill site includes the milling portion of
a former milling and smelting operation originally ovned and operated by
the U.S. Smelting, Refining and Wining Company (USSRIO, later knovn as UV
Industries, Inc. The operations vere in effect from 1910 to 1971. The
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seelter, vhich is located north of 7800 South Street, closed in 1958; the
cluing operation closed in 1971. Sharon Steel subsequently acquired the
ciii and tailings site in 1979. The s..lt.r is located on the Widval. Slag
Suparfund site, and, therefore, yes not investigated during the Sharon
SteellMidvale Tailings P1/PS (see Section 1.4.3 for detailed discussion).
In the .illing operation, sulfid. concentrates of lead, copper, zinc, and
other .etals vera extracted f ton or.. Tb. facility operated as a custo.
.111, receiving ores ira. cany sources for concentrating and extracting a
variety of ..tals.
.n environaental health proble. vu first suspected in June 1982, vhen the
Utah State Departent of Dealth vas notified that one or more citizens had
gathered vindblovn sand and tailings along 7800 South Street and vu
utilizing the .aterial for sandbozez and gardens. Tb. State Department of
Bealth analyzed a sample of the sand’ (obtained ftc. the citizen vho had
reovsd it near the site) and found that it contained 4,000 pp. of lead
(UD8 1982a). In August 1982, the Stat. umpl.d vindblovn tailings ito.
nine locations along 7800 South Street (UDI 1982b). The analyses shoved
elevated concentrations of arsenic, cadaiu., chrosium, copper, lead, and
zinc in the vtndblovn tailings.
In 1982, Sharon Steel Corporation erected a fence along the northern
boundary of its property. Hovever, tailings hays been blovu by the vied
through and over the fenc. and dovn the banka.nt of the bigh’vay right—of-
vay. In September 1982, the State Bureau of Air Quality requested that
Sharon Steel Corporation subsit a compliance plan for ths control of
fugitive dust from their tailings piles. Sharon Steel Corporation
responded to this request in October 1982 vith a proposal to us. vater
flooding to suppress th. dust. The State initially approved but
subsequently vithdr.v approval of Sharon Steel’s dust control plan and
issued another order to Sharon Steel to suppress the dust. Subsequently,
Sharon Steel i.plemanted a dust .itigation program in Nay and June of 1988
using a chemical polymer dust suppressant (see Section 1.3.2.2).
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In I1arch 1983, the St&te of Utah and EPA coepleted $ hazardous vests site
preli eiflaxl usesseentand sit. investigation of the Sharon Steel tailings.
Th, results indicated that elevated concentrations of aetals vere present
in the soil, air, and ground vater (EPA 1984).
In 1983, the U.S.G.ologiC*i Survey (USGS 1983) drilled veils at the
northvest corner of the sits, vhere 7800 SOUth Street crosses the Jordan
River. Saaplss f roe one of these veils contained concentrations of lead
that exceed the Safe Drinking Water Act (SDVA) eaxisue contaainant levels
(MCLS) standard for lead in drinking vater.
In early 1984, EPA ’s Yield Investigation Tm (PIT) cospleted a
docua.ntatiOn record and site asssssnent for the Sharon Steel/Midvale
Tailings cii i site (EPA 1984). This assess.eflt docuesnted elevated
concentrations of arsenic, cadaiu, lead, chrosiuc, and iron in releases
free the ciii site to the air and, possibly, ground vater. Releases to
surface vater and direct husan contact vlth these contaMnants vere also
considered possible. A score of 73.49 Va ’ assigned to the sill site. On
October 15, 1984, EPA proposed the ciii site for listing on the NP !. under
CERCLA. The current status of the ciii site is ‘in rulwking.’
Studies cospleted in 1985 included a reprocessing study conducted for the
State of Utah (Professional Mining Systons 1985) and a site investigation
conducted by potentially responsible party (PEP) Sharon Steel (Mont$0 5er7
Engineers 1985). Approxicatell 11 cillion tons of unconsolidated tailings
f roe the cilling operations vere reported to be located at the ciii site in
uncovered piles f roe 10 up to 40—50 feet deep. Arsenic, cadsiia, lead,
chrosiuc, copper, and zinc vere identified in elevated concentrations in
analyses of tailings saspies (Montgo.erY Engineers 1985, Professional
Mining Syst 1985).
After the site vu proposed for listing on the Nfl., the Utah uruu of
Solid and Hazardous Waste vu given funding by EPA to conduct an RI/PS at
the site. The State entered into a contract vith Caap Dresser and McX.e
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. in December 1985 to provide support to the State in conducting
these studies. Under the State Ri/PS, W v ms to undertake field sampling
nd analysis of mill tailings, soils, surface vater, air quality, and
gilding samples in the site vicinity. Due to hazardous vute insurance
gi d liability probleas, I4 could not conduct the ground yates portion of
the RI/PS under the State’s contract. In June 1986, to facilitate progress
g t the site, the State asked EPA to assume responsibility for the ground
vater.portiofl of the RI/PS.
During 1986, EPA continued to negotiate vith PEP5, including Sharon Steel.
In February 1987, EPA decided to assume responsibility for the RI/PS in
order to expedite the RI/PS investigation. EPA then tasked I1 to expand
their ground vater activities to include the full RI/PS for the site. The
CVM team began a phased RI/PS in June 1987. The Phase I sampling plan vas
designed as a screening phase to determine the general extent of
contamination. Any Phase I data that indicated contaminant migration into
ground yates or onto vicinity properties vould then be used to design a
Phase II sampling program that vould alloy site boundaries to be defined.
Phase I field studies for the RI vere completed in December of 1987. A
final draft of the RI vms completed in June 1988. Preliminary york on the
PS occurred betveen March 1988 and August 1988. During this time, the need
for additional data resulted in further field investigations (similar to
the previously planned Phase II ;tudies) of tailings, reprocessing, and
ground yates. These investigations delayed the PS until the additional
data could be collected. Results of a metals speciation study sad an
additional reprocessing study vere available in March and Nay of 1989,
respectively. Results fro. an additional ground yates investigation vere
available is Play 1989. It is estimated that results from an additional
residential soil investigation viii be available foiloving the signing of
the ROD for 01 )1 in September 1989; these viii provide data needed for the
01 )2 PS to estimate the voline of residential property soils in need of
remediation.
1—11
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In addition, EPA’a Emergency Response Team (UT), in cooperation with
Sharon Steel working pursuant to a consent order with EPA, completed
interim activities including fencing, dust prevention, and slope
stabilization of tailings piles during 1988 and the early part of 1989.
Following is a s i ry of these activities:
1.3.2.1 !! i I
The construction of perimeter fencing as proposed by Sharon Steel and EPA
was completed by Sharon Steel to limit site access. A fence was
constructed on an existing berm located on the east bank of the Jordan
River along the entire reach of the river bordering the vest edge of the
tailings. This fence connects with existing property boundary fencing.
The fencing is industrial grade, six-foot chain link topped with a 45’
angle extension arm fitted with three strands of barbed wire angling
outward free the site. An effort was made to place the fence on property
lines but in some instances it was located back free the property line to
provide a better fence base. The fencing encloses all the tailings but
still allows limited public access to the Jordan River.
Setback locations include:
1. Along the vest bank of the Galenà Canal where, in order to avoid
crossing the canal, the nev fence vu placed en the bank rather
than on the east property line.
2. Along Main Street vhere approximately 1200 feet of existing fence
vu partially submerged in a ditch. The new fence was placed en
the existing berm which vu originally constructed as a starter
dike vhen the river was rerouted to expand the tailings area.
3. Along 7800 South where a new fence vu constructed approximately 21
feet fros the edge of pavement to provide for the legal highway
right of vay. Tailings which had blown out on the shoulder of the
road were removed and placed within the fenced boundary of the
property.
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part of the security fence includes approximately 1,300 feet of existing
in link property boundary fence which had the 45’ angle extension are
yjth three strands of barbed wire added. In addition, a three acre plot
ovned by Sharon Steel vest of the Jordan River yes fenced separately from
the property east of the river.
1.3.2.2 Dust Prevention
A dust mitigation program yes commenced by Sharon Steal en Nay 19, 1988 and
completed on June 16, 1988 in response to a compliance order issued to
Sharon Steel by the Utah Department of Health, Bureau of Air Quality ( lAO).
Approximately 75 acres of tailings vere stabilized by spray application of
9,000 gallons of a polymer dust suppressant mixed with vater and 90,000
lbs. of wood mulch. £ second polymer dust suppressant application,
covering approximately 57 acres, vas completed Nay 24, 1989. The polymer
is designed to bind together the near surface soil or tailings particles,
forming a wind erosion resistant crust. Previous experience at other sites
has shovn that such a crust remains intact for one to two years.
1.3.2.3 Slope Stabilization and River Bank Restoration
In approximately five locations, the berm bordering the site had been
vaahed out by high river flows. This berm was rehabilitated and
reconstructed to serve three primary purposes:
1. To serve as a platform f or placement of the security fence.
2. To serve as a buffer zone between th. tailings and the river.
3. To serve as an access road for construction and maintenance
activity. This road has a width of approxitely 10 feet.
All tailings were roved from th. berm in these five locations as part of
this rehabilitation effort. These tailings were placed on existing piles
away from the river and embankeents were sloped to approximately 3:1
(horizontal to vertical) configuration. This york was performed along 600
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to 800 feet of the bers. £11 strean bank arW requiring repair vere
filled vith gravel eaterial, cospacted and covered vith a graded riprap.
Steept slopes resain on other portions of the esbankeent.
Existing obstructions in the river, including debris and s.diaent vhich
vere directing river flov into the tailings side of the river, have been
resoved and the river channel cleaned so as to redirect flov avay free the
east bank.
1.3.3 SITE GEOLOGT AND ETDIkOGEOLOGY
The Sharon Steel/Midvale Tailings study area is located in the Jordan River
Valley, $ flat, ,ediaent-filled valley surrounded by fault-block .ountains
typical of the Basin and Range physiographic region. The valley is bounded
on the east by the Vasatch Mountains, on th. vest by the Oquirrh Mountains,
on the north by the Great Salt Lake, and on the south by the Transverse
Mountains. The valley has been filled vith lacustrine s.di.ents deposited
in ancient Lake onn.ville, interlayered vith coalescing alluvial fans
derived f roe the ad joinin$ .ountaifl*. Unconsolidated sedisents axe
estiaated to exceed 2,000 feet in thicknesU hovever, the exact depth of
the sedisents in the valley is unknovn.
The ground vater systen beneath the Jordan River Valley underlying the sill
site consists pri.a ilY of a shallov unconfined aquifer overlying a deep
confined aquifer. The tvo aquifers are separated by deposits of clay,
silt, and fine sand ranging free about 20 to 40 feet in thickness in the
vicinity of the sill site. In sose parts of the salt Lake Valley, the
shallov unconfined aquifer has a perseabilitl only slightly greater than
that of the underlying confining bed. The .sxiiun thickness of the shallov
unconfined aquifer is about 50 feet. This aquifer is cosposed of clay,
silt, and fine sand. A portion of the tailings vers deposited on the old
river bed of the Jordan River, vhich vu rerouted to the vest, on its
present course, at the level of the shalloV unconfinSd aquifer.
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The top of the confining bed be]ov the shaflov unconfined aquifer is
generallY 50 to 150 feet b.lov ground surface (Bely et al 1971). The
confining bed is present at the site but its continuity throughout the site
js unknovn. The confining bed is absent along the eargins of the valley
vbers only a single unconfined aquifer •xists.
The ground vater units described in the literature have been identified at
the site. Tb. uppsrsost unit is a local perched zone of ground vater vhich
occurs vithin the tailings, and east of thea in terrace deposits. The
aiddl• unit (sha]lov unconfined aquifer) underlies th. tailings and terrace
deposits, and is separated f roe these perched zones by a layer of clayey,
unsaturated saterial. This unit is correlative to the diastes aquifer
described in previous Sharon Steel/Plidvale Tailings site reports. Ground
vater levels in this unit are closely related to the level of the Jordan
River. In addition, the shallov unconfined aquifer appears to discharge to
the Jordan River. Neither the perched zone nor the shallov tmconfined
aquifer are a current source of drinking vater vithin the boundary of the
Sharon Steel/Midvale sill site.
The lover unit is the deep principal aquifer. It underlies the sha]lov
unconfined aquifer and is separated f roe it by 20 to 40 feet of clayey
saterial. The deep aquifer is reported to be artesian in th. sill ste
area, and appears to discharge upvard to the overlying unit. There is sose
evidence, hovever, that heavy puaping of the deep aquifer could result in a
reversal of artesian conditions in localized areas. Given th. arid nature
of the region, it is likely that pusping of the deep aquifer esy increase
in the future. Tb. deep principal aquifer is a sajor source of drinking
vater in the Salt lake Basin. The Utah Division of Vater Rights has
recently conducted hearings regarding lisitations on vithdravals fro. this
principal aquifer, to prevent infiltration of shallov ground vater to this
deep zone. Presently allocated vater rights for the principal aquifer far
exceed aquifer recharge, according to the State.
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For a sore si.pflfisd discussiOn of the ground vater situation and probable
contamination, see the text and diagram in SectiOn 1.4.4.2.
1.3.4 SOILS
Th. soils in the Nidvale ares are closely related to each other and occur
on three different land festuress floodplain soils, terrace soils and
mining industry artifacts. The Jordan River Floodplain lies along the
Jordan River b.tvesfl the North Jordan and Galena canals. The floodplain
includes Braavell, iipean and Nagna soils and mixed alluvial and sandy
alluvial land units. Tb. terraces are from the Great Salt t ./Lak*
Bonneville system, vith Taylorsville , gilifield, K.id ” , Velby, Portleys
and Iarrisville soils. Tb. artifacts from th. mining industry include
dumps of tailings and made-land. lade—land is a ,iscellaflsous land type
consisting of areas covered vith such aterial as gravel, rock, concrete
blocks and non organiC material other than soil.
Different soil types occur in different portions of the study area, namely:
o Silty soils on the terrace vst of the sill site
o Silty to sandy soils on the floodplain
o Sandy soils on the terrace east of the mill site vith primarily
residential land use
- o Sandy and slag_cofltaminst sd soils on the mill site.
The mill sits is located on floodplain soils, the residential area is on
terr soils and th . agricultural ares is on floodplain and terrace soils.
Made-land has bean observed at the si te and the residential area.
1.3.5 SITh u OLOGT
Portions of the Sharon St.el/Ptidvale Tailings sill site, including most of
the tailings piles, ii. in the floodplain of the Jordan River vhich forms
- the western and southern boundaries f or the mill site. The Jordan River
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floes north from Utah Lake to the Great Salt Lake. Ristorlcafly, the
Jordan River flowed through the mill si te, but it was relocated to the vest
of the site in the early 1950s to facilitate tailings deposition.
currently, the tailings for. an embankment which limits flooding on the
east side of the Jordan River. The tailings piles previously were
contained by tailings dams, and remnants of these dams remain. Surface
water run-on generally flows into 1ev areas of the tailings, especially
these vestiges of the old ponds. Runoff is generally uncontrolled, but
appears minimal.
The Jordan River, in the reach bordering the Sharon Steel/Midva].e Tailings
mill site is classif fed by the State of Utah for the following uses:
recreation, excluding svieming (Class 2B); cold water game fish (Class 3A);
and agriculture (Class 4) (UVB 1978). Ten irrigation intakes from the
Jordan River ii. vithin three miles dovnstreaa of the mill site and
irrigate approximately 160 acres (EPA 1984). Stream classifications change
approximately eight miles dovnstrea. from the mill site at the confluence
with Little Cottonwood Creek. At this point, the fisheries classification
becomes 33 which is protective of warm—water game fish; the other
classifications remain the same.
Stream f 1ev measurements fro. the Jordan River during the RI indicated
average flow conditions for the month of August. With the exception of
linghaa Creek vhich enters fro. the vest, the quantity of flow coming from
all other Jordan River tributaries in th. vicinity of the mill site is
insignificant when compared to the flow of the Jordan River. Plow data
indicated Bingham Creek comprises 13 percent of the Jordan liver floe at
the downstream boundary of the mill site (7800 South). Perched water from
the tailings discharg, into the Jordan fro. a seep at a rate of
approximately 0.0001 cfs. ø annelization of the Jordan River in the
vicinity of the mill site has resulted in so.e unstable banks some of
which were repaired by Sharon Steel during early 1989. There is evidence
of past erosion along the east and vest bank of the Jordan Liver as it
passes by the mill site.
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1.3.6 TAILINGS STABILITT
The stability of the tailings pile located adjacent to the Jordan River vs.
evaluated during the RI in order to determine th. potential for collapse of
tailings into the river. The results of the slope stability analyses is
the RI report (CDI I 1988b) indicated that:
1. In its existing configurations much of the tailings pile perimeter
is unstable or marginally stable under static or pseudostatic
loading conditions. Failures from either deep or shallov slip
surfaces could adversely impact the Jordan River.
2. Flattened perimeter side slopes of 3:1 (horizontal to vertical)
vould stabilize the tailings pile for static loading conditions and
pseudostatie loading conditions using seismic coefficients on the
lover end of the O.15g to 0.30$ range. Most of the perimeter side
slopes have not yet been sufficiently flattened.
3. Even flattened perimeter slopes viii apparently not stabilize the
tailings pile for pseudostatic loading conditions using seismic
coefficients on the upper end of the O.15g to O.30g range.
4. Continued undercutting of the to. of the slope by the Jordan River
may destabilize portions of the tailings pile vhich are currently
stable or areas made stable by resediation. Areas of marginal and
unstable slopes resulting from the evaluation are shovn in Figure
1—4.
As described in Section 1.3.2.3, hovever, Sharon Steel has rehabilitated
and reconstructed some of these slopes along a 600—800 foot reach of the
Jordan River.
1.3.7 D IOCRAPHT AND LAND USE
According to 1980 census data, approximately 1,M0 people live vithin 0.25
mile of the mill site and 8,180 people Liv. vithin one mile of the mill
site. Occupied residential and commercial areas lie immediately adjacent
to the mill site on the east. Producing agricultural lands are located
immediately across the Jordan River on the vest side of the mill site.
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Vind patterns in the vicinity of the .131 site incr.ase the likslihood that
populated areas nearby say be exposed to airborne contaminants.
The City of Nidvai.e is located adjacent to the iill site to the east.
Nidvale currently has a population of about 12,200 with approximately 4,300
dwelling units and a land area of approximately 3.4 square iii. , (City of
Midvale 1987). Th. city has a planning coission and has adopted a master
plan and zoning ordinance. This has allowed the City of Midvale and Sharon
Steel Corporation to explore alternatives with various parties for both
recovery of .stals from the tailings and reclamation of the mill site for
co .aercial develop.ent.
The deep confined aquifer is a source of drinking vater for Salt Lake
County. Municipal supply veils operated by Murray, Nidvale, Sandy City,
and the Salt Lake Vater Conservancy District are located vithin three miles
of the Sharon Steel/Nidvale Tailings •ill site. The nearest dovngradient
municipal supply well currently in use is located approximately 1.5 miles
north of the mill site in Murray. The direction of ground water flow for
the deep confined aquifer is believed to be vesterly, tovard the Jordan
River and then north, tovards Great Salt Lake (lely, et .1 1971; Vaddell
1987b).
Th following public eater supply wells, located within a three—ui. radius
of the site, draw water from the deep confined aquifer. In addition,
approximately 32.5 people are served by private veils fro. the deep aquifer
in the sase area.
Location Number of yells Population Served
Salt Lake City 5 (part of blended system) 300,000
Sandy City 7 83,700
Midvale 5 10,000
Murray 1 28,000
Private Veils Not Listed 325
1-20
-------
1.4 NATURI AND EXTVIT OF CONTAMINATION
This section revievs the nature and extent of contamination based upon RI
data and s additional data available after the RI. One of the key
factors in assessing the nature and extent of contamination is the degree
of public health or environmental risk posed by the contaminants. For
.,‘imple, if there is no current or potential future migration pathvmy or
receptor for a contaminant, then there is essentially no risk. The U
completed during the II revi.ved 11 potential contaminants of concern and
revieved the potential migration pathvays and potential receptors for these
contaminants to determine the degree of risk posed by the mill site.
The folloving three sections su rize the results of the U regarding
contaminants of concern (Section 1.4.1), potential migration pathvmys and
receptors (Section 1.4.2), and the risks posed by the site (Section 1.4.3).
Section 1.4.4 revievs the extent of the nature and extent of contamination.
1.4.1 CONTAMINANTS OF CONCDN
The LA included in the II report (CON 1988b) identified the folloving
contaminants of concern in the mill tailings: aluminum, antimony, arsenic,
cadmium, chromium, copper, lead, manganese, silver, thallium, and zinc.
Sued upon site-specific data, the LA determined that arsenic and lead pose
the most significant threats to both human health and the environment.
This PS focuses on reducing arsenic and lead exposures.
1.4.2 - POi TL&L )II ATICW PATIWAYS AND UCEPTORS
Under cur S and potential future land use conditions at the Sharon
Steel/Mid * Tailings study area, the LA determined that the principal
migration pathvays by vhich human receptors could potentially be exposed to
site contaminants are:
1—21
-------
o Direct ingestion of tailings or contasinated surface soils
o Ini alation of tailings-contasinated dust
o Ingestion of produce grovn in hose gardens located in the study area
o Ingestion of contasinated ground water
Environeental receptors (aquatic life and wildlife) could be exposed via
the ease routes (except ground vater) and, in addition, via ingestion of or
contact with contasinated surface vater and s.diients. Environsental
receptors include cold water gase fish, aigratory vaterfovi, end
terrestrial isseals. Ingestion of these receptors by hu.ana is not
considered to be a significant pathvay due to 1ev exposure rates. These
receptors are discussed in sore detail in the RI report. £11 potential
receptors and exposure levels at. discussed in sore detail in the LA.
1.4.2.1 Soil/Tailings
Direct ingestion of tailings or conta.sinated soil is a potentially
significant route of exposure. Toung children ((6 years) constitute the
sost sensitive population, via the norual outhing of soiled objects, their
hands, or the actual consuaption of dirt. Older children are less likely
to eat soil or to south soiled objects, but they say still ingest dirt ira.
their hands. Sisilarly, although adults say ingest sash asounts of
contasinated soil or tailings, they an, less likely to be exposed by this
route. Derial absorption is a less isportant route of exposure, and
generally 1i.it.d to instances where exposed cuts or scrapes ahoy
absorption through the skin. Such instances would occur vhen persons get
dirt/tailings on their skin or clothes during work or play activities, or
via exposure through clothes handling (e.g., laundry).
Taillngs—contaainated soils on or near th. sill site an. also available for
uptake by vegetation. Consuaers of garden vegetation or produce in the
area may be potential receptors.
1—22
-------
1.4.2.2 4j
Air transaission of contazinants say occur during the vindy, dry periods of
aid to late suer. In addition, off-road v.hicle use on the sill site say
lead to inhalation exposures. Airborne release say also occur, to a
lisited extent, during resoval or stabilization as a part of potential site
resediation activities If protective s.asures are not taken. Migration
pathv*Y$ correspond to local vind—flov patterns. InhAlation exposure is
contifl(eflt on the receptors being relatively close to the sill site,
although ss..ll particles, less than 10 sicrons in size, say be carried
great distances, but will usually be v.11—dispersed and in low
concentrations. It is estiaated, further, that only a ssall proportion of
the tailings are less than 10 sicrons in size, adapting sose previous P.1
data ( N l988b).
1.4.2.3 Ground Vater
Ground vater provides a pathway for transporting contasinants off the sill
site. Specifically, saturated unconsolidated deposits in the Jordan River
Valley say receive aetals leached fro. the tailings. Laboratory tests were
conducted to deterain. the potential leachability of etala f roe th..
tailings pile. The sathodology used vas the P.? toxicity test (a leach with
sild acetic acid). Results indicated that 10 of 14 tailings sesples
exceeded EPA leachability hefts for lead and 3 of 14 for cad.iua. One
soil sasple f roe the ciii site also exceeded the leachabihity hi.it for
lead ( I4 1988).
Three ground water sources are potentially subject to .etals contaain.atiofl
ir e . the sill sit.. The first is perched ground water within the tailings
piles. This perched water, however, is hiuited in extent to vi thin the
tailings and would not be considered a viable source of drinking water.
Sose of this perched vater currently seeps into the Jordan River, but no
adverse ispacts to river water quality were detected. There is sos .
1-23
-------
indication, hov.v.r, that this perched ground vater discharges into the
stiallov unconfined aquifer described belay (CDII 1988).
The second ground vater source is a shallov unconfined aquifer that extends
beyond the .111 site. Regional veils in this aquifer have by metal
concentrations but high average TDS (1,695 eg/L) and sulfate (2,130 g/L).
Dovngradient of the .ill site, this aquifer discharges to the Jordan River.
This aquifer is not currently used as a drinking vater source either on or
dovngradient from the .ill site. According to EPA’s ground vater
classification, this aquifer is 23 (potential drinking vater source), and
its future use viii be addressed in this PS.
A deep confined artesian aquifer also occurs vithin the study area and is a
primary drinking vater source for the Salt lake County Water Conservancy
District, vhich serves 300,000 people. The nearest operating municipal
supply veil, dovngradient of the .ill site, is located approximately 1.5
miles to the north. Available data f ron this yell indicate that the deep
aquifer is not currently contaminated by metals. As noted previously,
vithdravals f ran this deep aquifer are under study by the Utah Division of
Water Rights. Also, see Section 1.4.4.1 for a diagram of the ground vater
situation.
1.4.2.4 Surface Water
The surface water system represents a potential route of exposure. Both
the Jordan River and a 22-acre wetland on the mill site are subject to
metal releases from the mill site. Diuolved and suspended metals may be
released to, and transported by, the surface vater systan. Jordan River
sediments and vet]and sediments may currently act as a ‘sink’ for metals
fro. the site. These sediments may also be resuspended and diverted
dovnstrum during high flows.
1-24
-------
CURRENT RISE CRARACTERIZATION
1.4.3.1 Risk characterization for Dusan Receptors
The greatest carcinogenic risk at the Sharon Steel/Midvale Tailings study
area under both current and future use conditions is th. direct ingestion
of contacinated surface soil/tailings end the ingestion of leafy and root
crop! grovn on conta.ainated soils.
carcinogenic risks posed by ingestion are the result of exposure to
arsenic. Under current use conditions, for the average case, children and
adolescents living in residential areas are at the greatest risk (4x10 6 to
2x10 5 ). For the reasonable caxicue case, children playing in sandboxes
containing tailings, anyone living in the residential area, and adults
consuing leafy and root crops are at the greatest risk (2x10 3 to 1x10 3 ).
ReaediatiOfl of these risks viii be addressed in 0U2.
carcinogenic risks on the .111 site (OU1) viii be dependent on future land
use of the ciii site. For purposes of developing action levels (cleanup
goals) for the sill site, tvo future land use scenarios have been
considered. One scenario considered is residential deve]op.ent of the ciii
site. This scenario vould allow for unrestricted use of the sill site in
the future. The second scenario considered is tight industrial
developsent. Evaluation of this scenario considers potential exposures
received by construction yorkers on the sill site. Appendix D describes
these scenarios and the deveiop.ent of corresponding action levels in core
detail:
carcinogenic risks posed by inhalation of airborne conta inant$ are the
result of exposure to arsenic end cadalus. Although these risks appear to
be relatively by (4x10 6 to 4x10 5 ), there is s evidence presented in
the RI that the risks for inhalation exposure say be underesticated.
1—25
-------
The greatest toxic (non_CarCiflOPflk) risk at the Sharon Steel/Kidvale
tailings study area under both current end future use conditions is posed
by the ingution of lead. Under current use conditions for 0112 and the
future residential use scenario for the sill site, children are at the
greatest risk folloved by adults consuming vegetables under reasonable
maxisus case assumptions. At this ties, EPA has vlthdravn the reference
dose (RfD) for lead (previouslY knovn as the Acceptable Daily Intake (ADI))
and is valusting lead toxicity. Research indicates that lead .ay be
sore toxic than previouslY estimated. Specific health risks associated
vith lead exposure are further analyzed in S.ctiofl 5.3 of the IA and in
Appendix D of this PS.
1.4.3.2 Risk Characterization for gnviroiaental Receptors
The potential threats to vegetation, aquatic life, and vildlife posed by
the chemicals of concern at the Sharon Steel/Midvale Tailings area vera
considered. The major conclusions of this evaluation are sn..arized b.lov.
Lead is known to be phytotoXic at soil levels as by as 100 pp.
(Kabsta -PefldiU and Pendiu 1984). Soil i..a concentrations exceed this
level over a large portion of the study ares, especiallY 00 the .111 site.
Aquatic Life
Aquatic life can be exposed to contaminants in both surface vater and
s.di.entl. Undercurrent conditions, one metal, zinc, is present in the
river at unnaturally high concentrations dovnstream of the sill site, but
the zinc concentration at this location (35 ugh.) is bela ’ the federal
Ambient Water Quality Criterion (AVQC). The concentration of zinc in the
river is, therefore, considered unlikely tO adversely affect the fish
population. Of greater significance are the unnaturally high concentra-
tions of .tals in the river sediments. These sediments saY act as a
1-26
-------
;,servoir vhieh supp]ies metals to the vater co usn or may directly
adverselY affect benthic organisms.
Wildlife
nalysis of surface vaters and sediments from the vetlands adjacent to the
tailings piles indicates that zinc concentrations are unnaturally high in
surface vater and several metals are present at unnaturally high
concentrations in sediment. Vildlife in the v.tlands habitat say be
exposed to site-related contaminants directly through contact vith
contaminated surface vaters or sediments, through consumption of organisms
living in the surface vaters or sediments, or through consumption of larger
insects or animals feeding on these organisms. Some metals are knovn to
accumulate in animal tissues vhich may serve as a source of exposure for
large predatory birds, such as the vhite—faced ibis or other terrestrial
animals. Among the metals present at the study area, lead has been shovn
to bioconcentrate in insects, small .als, and songbirds vhteh may then
be consumed by larger animals (Beyer et al 1985). It is uncertain vhether
vildlife in the vetlands habitat is currently being adversely affected by
the metals present at the study area; hovever, the potential does exist for
vilditfe exposures that may lead to adverse effects.
1.4.4 EXTDIT OP CONTAJ1INATION
Table 1—1 lists the geometric mean for the contaminants of concern detected
in the various media. Complete laboratory data results are reported in the
RI ( 1988b). The tolloving subsections describe the extent of
contamination in soils, ground vater, surface vater, and sediments. The
focus of this PS for Operable Unit 1 is on mill site contamination. Some
references to off—site contamination are included in the foiloving
sections, but the full extent of off—site contamination viii be described
in detail in the PS for Operable Unit 2.
1-27
-------
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In order to determine the extent of contamination, a bu. concentration
level for each contaminant bad to be established. Local background levels,
as described in the RI, vere used as the basis. Table 1—1 lists local
background levels determined during the RI.
1.4.4.1 Soils and Tailingi
Due to the history of smelting activity in the Salt Like Valley, it vu
considered unlikaly that vs vould find any uncontaminated soils in the area
vhieh could serve as an estimate of natural background. When analyzing the
of f—site soil data, hovever, it vu apparent that the soil data folloved a
bimodal distribution vtth samples < 150 egIT. g forming one node and samples
> 500—700 mgllg forming a second node. It is also apparent that th. lover
concentrations occur farther fro. the mill site than the higher
concentrations.
No samples from the residential area or the sill sits had lead values belov
150 mgIT g lead. Four samples f roe floodplain soils and 23 samples from
terrace soils vere belov 3.50 ug Y g for lead and vere used to estimate
background contamination levels for these soil types.
£ suite of inorganic contaminants exist at high concentrations in the
tailings; from high to 1ev concentrations in mill site and off iill site
soils; and in sediments of the Jordan River. The suite of contaminants
includes antimeny, arsenic, cadmium, copper, lead, silver, and zinc.
Figure 1-4 ahoy. .chtically the extent of tailings and soils on the sill
site. Tailings cover 207 acres east of the Jordan liver and an area 2.3
acres in siz, just vsst of the river (not ahoy in Figure 1-5). The main
tailings pile has $ vsight.d average depth of approximately 36 f.et and the
vestern area is estimated to be approximately 6 feet damp. In addition, a
6.5 acre area on the sill site is covered approximately 8 feet damp vith
concentrated pyrite materials. Tvo areas of surface soils also exist on
th. mill site: 41 acres in the vicinity of the sill buildings and 1.3.5
acres along the original channel of the Jordan liver.
1—29
-------
0 500
TAiLINGS AREA DESIGNATION
YEARS OF TAIUNG DEPOSITiON
ON—SITE SOIL AREA
SHARON STEEL/MID VALE TMUNGS SITE
MIDVALE. WAI4
DESiGNATION CF TAIUPIGS/SOILS AREAS
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1—30
-------
5 read of contasiflation to the deep confined aquifer (vater supply aquifer)
j, unlikely to occur unless influenced by heavy pusping f roe vater supply
vell in the area. If the gradient is reversed due to heavy pueping,
contsainated ground vater could start to f 1ev dovnvard to the deep aquifer.
1. • •3 Surface Water and Sediments
Surface vater and sediments sasples vere collected f roe upetreas and
dovnstreai in the Jordan River and from accessible surface vater on the
.ill site. Results for vater and sediment aseples are listed in Tables 1—3
and 1—4, respectiVely.
Sediment data indicate that tailings are migrating from the sill site into
the Jordan River. This migration may be due to ongoing erosion or previous
slope failures along the vestern boundary of the sill site. These data
also indicate that vetland sediments contain tailings.
Water quality data suggest that in the Jordan River, dissolution of metals
from transported tailings to the aqueous phase yes not significant at the
time of saspling. One factor potentially responsible for reduced
dissolution of metals is the lick of significant fluvial transport of
sediment or tailings material, as indicated by by TSS values (59 to 61
mg/L). A second factor could be th. high Jordan River pH values (7.5 to
7.8). At these pH values, metals vould tend to remain bound to the
sediments.
With the exception of the seep visible along the side slope of the tailings
above the river, none of th. surface vater sasples exceeded metals criteria
for the protection of aquatic life. Although metal concentratiOns vere
high in the seep, Jordan River vater quality did not appear to be adversely
affected. The potential exists for continued undercutting of the tailings
piles by the Jordan River and related local slope failures vhicb could
increase etal concentrations in the river, hovever, recent slope
stabilization activities (Section 1.3.2.3) have reduced this possibility.
1—40
-------
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Sharon SteelfMidvale Tailings Site Mining Waste NFL Site Summary Report
Reference 4
Excerpts From Declaration for Record of Decision - Sharon Steel
(Operable Unit 2) Residential Soils, Midvale, Utah;
EPA Region VIII and the Utah Department of Health;
September 24, 1990
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.
DE LM A11ON FOR 11€ OF DEC ON
Sharon Steel (Operable Unit 02)
Residential Soils
dvale, Utah
September 24, 1990
U.S. Environmental Protection Agency Region VIII
Utah Department of Health
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DECLARA11ON FOR ThE RECORD OF DECISiON
STE NAME AP LOCATION
Sharon Steel (Operable Unit 02, Residential Sods), Midvale, lJtaJi
STATEMENT OF BASS AP PURPOSE
This decision document presents the selected remedal action for the Sharon Steel, Operable
Unit 02 (0U2) Site, in Midvale, Utah. The selected remadal action was chosen in accordance
with the reqi rements of the Comprehensive Environmental Response, Compensation, and Liability
Act of 1980 (CERCL.A), as amended by the Superfund Amendments and Reauthorization Act of
1986 (SARA), and the National Cd and Hazardous Substances Pollution Contingency Plan (NCP).
This decision is based on the Administrative Record (AR) for this Site.
The State of Utah concurs with the selected remedy, as indcated by cosignature.
ASSESSMENT OF ThE SlT
Actual or threatened releases of hazardous substances at and from this Site. if not addressed
by implementing the response action selected in this Record of Decision (ROD), may present an
imminent and substantial endangerment to the pubdc health, welfare, or the environment.
DESC PTION OF ThE SELECTED REMEDY
The selected remedy for Sharon Steel 0U2 addresses the sod contamination in the residential
and commercial area immedately east of the Sharon Steel ml site (Operable Unit 01 (CU 1)).
These sods in O1J2 are contaminated with talngs blown from the ml site and contaln elevated
levels of lead, arsemc, and cadmium.
The action descit ed harem is the first part of a two-step remedy and addresses the most
immedata threat to pubde health. It cons4ts of excavation of the contaminated sod and
plcemflof fr 0 the residential areas, temporardy, at the ml site (OUI). A
separate ROD wI, at a later date, address the remedy for the talngs already present at the ml
site and the contaminated residential sods temporardy placed there as a result of this initial
action. The major components of the first phase of the remedy (0U2) include:
o Removal of contaminated sods and associated vegetation, to the action leveL The level of
contamination which would thgger removal is 500 parts per muon ( ppm ) lead and 70 ppm
arser c ice. ons in the sod. Existing sods being used for gardening would be
remedated to the action level of 200 ppm lead and/or 70 ppm arsenic.
o The sods removed from this area wI be transported to the ml site (OU1). The remedy
selected for the ml site wi address the tathngs at the ml site and the contaminated sods
from 0U2, tempcra Iy placed there as a result of this action.
o Clean sod wI replace the excavated sods back to the ori nal ground surface.
o Clean sods wI be graded to the ori nal contour arid revegetated.
-------
o The residents wifi be offered the opportunity for temporary relocation, if monitoring of
a test site suggests this is necessary.
o Homes w be tested and cleaned to remove household dust if the dust exceeds the
action levels for lead and arsenic, following outdoor cleanup.
o if removal of the soils affects their viabifity, trees and shrubs will be removed and
replaced where possible only if this is necessary.
o InstItutional controls w be implemented to provide special provisions for future
construction when removing or replacing existing sidewalks, driveways, foundations, etc.
which may have contaminated soils beneath them, and for initiation of new gardens.
The selected remedy wifi remove the principal threat at 0U2, the exposure of the residents
to unacceptably high levels of lead and arsenic in their soil. The sod presents a hazard
particularly to children who can ingest the sod drectty, ingest the sod by eating food with c rty
hands, inhale the dust from the sods, and ingest contaminants in vegetables wown in the sod.
AU of these exposure pathways will be reduced when the immedate sources of the exposure - the
contaminated soils in their yards and gardens - are removed
STATLT ORY DETERMNATION
The selected remedy is protective of human health and the environment, compiles with
Federal and State reqLñrements that are legally applicable or relevant and appropriate to the
remedal action, and is cost-effectiva This remedy uses permanent solutions and alternative
treatment (or resource recovery) technologes, to the maximum extent practicable for this site.
However because treatment of the princ al threats of the site was not found to be practicable,
this remedy does not sati5fy the statutory preference for treatment as a principal element.
Because this remedy will result in hazardous substances remalning on-site above health-based
levels, a review will be conducted within five years after commencement of remedal action to
ensure that the remedy continues to provide adequate protection of human health and the
environment-
s ROD W i be fo owedby another Operable Unit ROD which Wi address the final
remedatlon of the Site.
0 -
-. --- - -
James herer /
Regon dm i trator
United States EnvEcnmental Protection
Regon V II
-
‘ /Date
Agency
enneth Alkema
Director
Utah Division of Environmental Health
a-
\
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DECISION SUMMARY
Sharon Steel Operable Ult 02
Residential Sois
ibdvale, Utah
Septenther 24, 1990
U.S. Envi’omiental Protection Agency, Re on Vi
Utah Department of Health
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DECISION SUMMARY
1. & E NAME, LOCATION, A D DESCRiPTION
The Sharon Steel 0U2 is kicated in Midvale, Utah, bounded on the west by Sharon Steel OU1
mill bui1 ngs, site, and tailings, on the north by 7200 South Street, on the east by a llne one
or two bidcks east of Interstate Highway 15, and on the south by the newer residential and
commercial area in south Mdvaie City. The exact boundanes of the site, however, are
imprecise due to the widespread nature of the contamination. A map showing the approximate
location of 0U2 and its relationship to OUI is ven in Figure 1.
There are three main topographic and gedogc features of the Sharon Steel site: Jordan River
Fk,o Ialn, terraces from the Great Salt Lake/Lake Bonnev e system, and artifacts from the
mining industry. The tathngs (OUI) from the mill are located on the Jordan Rh,er floo leln,
and the m site (OU 1) and nearby residential area (0U2) are on the terraces The terrace
soils, having on nated from the weathenng of sedmentary and igneous rocks from the
Wasatch Mountains, are generally well drained.
0U2 encompasses part of the City of Midvale, Utah and surroundng areas. Approximately
44,000 people hve within a two mile radus of the mill site, 12,000 within the City of PJridvaie,
8.000 peoplellve withinone mile, and 1,400 People ye withina mileof the m s ite.
Theagedstrlbutionis:36- 39%from0 - l6years;48 -49%from 17-S4years;arid 11-
16% over 54 years.
The land south and west of Midvale s used primarily for agricultural and commercial
activities; the land north and east of Mdvale is mostly urban . The entire area dralned by
the Jordan River which provides cold water and warm water habitat for fish, but is more
heavily used for agncuttural irrigation. Adjacent to the Jordan River are wetlande, and
potential wik fe habitat. but these features are not within 0U2. The Salt Lake Valley has
substantial ground water resources consisting of shallow and deep aquifers used for various
domestic, agricultural and industrial applications. There are a number of pttiic thinking water
supply wells within a three mile radus of the Site, most of which use the deep aquifer.
These serve approximately 440,000 people. Recent data suggests that the shallow and deep
aqwfers are hy&auilcally connected. However, the Rl/FS shows that orgy the sh ow a
drectly under the m site itself (OU 1) has been contaminated Ground water issues w
considered as part of the later OU1 remedy. To date, none of the ptdc water s ply wells
have been contaminated
2. &rE I4STORV APC ENFORCEMENT ACTIVITIES
The Sharon Steel Site includes a former milllng operation ori rially owned and operated by
the U.S. Smelting, R&hng arid r’druiuig Company, later known as IN tnthistnes, hic. The m
operated from 1906 to 1971. During the mi ng operation, sulfide concentrates of lead,
copper, and vnc were extracted from the ore by froth flotation. The facity operated as a
custom mi, receiving ore from many sources, then concerikatiug arid extr& 1iflg a variety of
metals. The tailngs from the m ng operations are located at the mi site (OU1) m
uncovered piles to 50 feet deep, and have an estimated volume of 14 mion cubic yarda.
I
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The t ngs are fine ç ained and the pies resemble sand dunes. Sharon Steel purchased the
mlsitem 1979.
An environmental health problem was first suspected m 1982 when the Utah Department of
Health was notified that local citizens were gathering wind blown tMngs and then using them
for sandoxes and gardens. The talings had high concentrations of lead, cadmium, and
arsenic. A pttic education campagn was launched to warn residents about the dangers of
this practice. In adckbon to the residential use of the t Ings, an investigation in 1988
revealed that talhings and other dusts had been blown by the wind and had contaminated the
sd with lead, cadmium, arid arsenic, over a 571 acre area of the City of Midvale downwind of
the ml site. Analysis of the contaminants in the sd stron y suggest that a major
contrtutor to 0U2 contamination s due to wind-blown t Ings from the Sharon Steel ml
site. Some of the contamination may also have orignated from the smelter at an adjacent
St erfund site (Midvale Slag). Of the 571 acre residential area contaminated by the t ngs,
further investigations have revealed that about a 142 acre area (with an estimatd volume of
242,000 cttiic yerda) ties sois which contsin levels of lead and/or arsenic above the action
level of 500 ppm lead and/or 70 ppm arsenic.
The Sharon Steel site, inclu&ig both the ml site (OU 1) off-site sols contaminated
areas (0U2), waspr sedortheS erfundNationalPrioritiesList(NpL)in 1984 andbecame
final on Au jst 28, 1990. The State of Utah was the lead agency for the Site between 1985
and 1987. Since 1987, the U.S. Environmental Protection Agency (EPA) has been the lead
agency. The initial Remedal Investigation (RI) for the site was completed in June 1988. A
Feastlty Study (FS) for the entire Site was pt shed in June 1989, and a Proposed Plan
issued in Jily 1989. A pt ic hearing on this Proposed Plan was held in Au st 1989. As a
restit of extensive ptdc comment, EPA decided to dvide the Site into two operable units,
with OU1 referring to Qround water, the ml site, and its t ngs, and 0U2 referring to the
residential sois contaminated by wind blown t lngs. The decision to c vide the Site into
operable units was based on the endangerment presented by the residential sois and the need
to further investigate the round water beneath the ml site. issuance of the ROD was
postponed for one year to ow adi bonal studes to answer questions posed by the ptt ic.
Further RI/FS studes and reports concerning wound water and residential sois were
completedduring 1989 and 1990. The FSforOU2 was completedon June 6, 1990. andthe
Proposed Plan was issued on June 6. 1990. A pt Ic hearing was held on th Proposed Plan
forOU2onJune 14, 1990,inMldvale, Utah.
Whie the St erfund process is underway, the State of Utah has been working with Sharon
Steel to stçpress the release of fu tive dust from the ml site to prevent further
contamination of the residential sols and to prevent re-contammation after implementation of
the remedy.
Three Potenti y Responsbe Parties (PRPs) have been identified at the Site. These include:
(1) Sharon Steel Corporation - the current owner of the ml site; (2) UV Industries, Inc. and
UV Industries, Inc. LiqLidating Trust - the former owner and operator of the ml site; and (3)
Atlantic Richfield Company - a generator of hazardous stiistances dsposed of at the ml site
and a potential former operator of the mt General notice letters were sent to the PRPs on
Au ist 28, 1985; and requests for information were sent on May 12, 1988 (CERCLA 104e). No
special notice letters have been sent. Al of these parties have been named as defendants in
2
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Crftenon 4 : Reduction of Toxicity, Mobity, or Volume Through Treatment
is the antic ated performance of the treatment techndo es a remedy may employ.
lthOugh containment options do reduce mobity, this is not ‘treatment’ m the context of
this criterion. This criterion reflects the statutory preference for treatment alternatives.
or y two of the alternatives classify as treatment: Alternative 4 ( stabization ) and
Alternative 5 (sod washing). Alternative 4 ’s treatment would decrease toxicity and mobity
,ut increase volume. Alternative 5’s treatment would reduce toxicity, mobity, and volume.
Alternative 3c may meet this criterion if sods stored at OU1 receive treatment ui the future.
Criterion 5: Short-term Effectiveness
This criterion addresses the period of time needed to achieve protection and any adverse
effects on human health and the environment that may be posed during the construction and
hiplementation period, unti clean t goals are achieved Because there is no construction
required in Alternative 1, the ‘no action’ alternative, there would be no risks in addtion to
those already present Alternative 2 does not reqiAre any movement or transport of
contaminated sods, therefore, tughive dust from this source wi be mnmal. Alternatives 3
through 5 od re Ere movement of contaminated saL so there is some threat of exposure via
fu tive dust emissions. Exposure via fug tive dust wi be minimized for these alternative
by temporary relocation of the residents during construction, and by use of dust siçpression
methods.
Criterion 6: hiipiementabity
frnp4emental ity addresses the techilcal and adm mstrative feastity of the remedy, includng
avail ity of materials and services needed to implement a particular option . Because
Alternative 1 requires no action, it is easdy implemented Alternatives 2 through 5 use
technolo es_and construction that are ready av thle. Alternatives 3 and 5 re ire dsposal
sites and therefore pose more dfflculty, but nonetheless dsposal c adty is av le.
Alternatives 3 and 4 re ire moderate coordnation with local officials aid Alternative 5
reqiires a high degree of coorJnation because of the production of sod washing effluents
which wi recire dsposal.
Criterion 7: Costs
Cost factors include estimated cØtal and operation and mEitenaice ( O&M) costs , as wd as
present worth costs . Alternative 1, the ‘no action’ alternative has UtIle c Atal costs but
does re ire monitcwñig and therefore OW expencUtures. it is obviously the least ccstiy
alternative. Alternatives 2,3c, and 4 have moderate costs in the $20 mion range.
Alternatives 3a, 3b, aid 5 have sttstantiiy higher costs ($70-90 mion).
Criterion 8: Stets Acceptance
This criterion indcates the State’s preferences regardng the various alternatives. The State
of Utah st ports Alternative 3c as evidenced by its testimony at venous pi ic mee ige, and
its written s mittal cUsing the comment period
16
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REMOVE AND DISPOSE
OF SOD AND VEGETATION
REMOVE CONTAMINATED
SOIL AND DISPOSE OF.
AT THE MILL SITE
REPLACE WITH
CLEAN SOIL
RE VEGETATE
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I
O.u.1
MILL SITE
PLACE CONTAMINATED SOIL
ON LINER AND COVER
WITH PROTECTIVE CAP;
SOIL WILL BE KEPT.
SEPARATE FROM TAILINGS
Figure 3
Alternative 3c:
Soil Exca va tion and Disposal
O.U.2
RESIDENTIAL SOILS
before
S
CLEAN SOIL
>
after
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Criterion 9: Community Acceptance
This criterion addresses the public’s general response to the alternatives descrli,ed in the
Proposed Plan. Most of the residents interviewed and local political officials supported
Alternative 3c.
Of the various alternatives proposed. Alternative 3c was the best overali hi satisfying the nine
remedy selection criteria of the NCP.
9. THE SELECTED REMEDY
EPA has chosen Alternative 3c as the selected remedy ( lustrated in Figure 3) for the Sharon
Steel Operable Unit 02. In summary, this alternative has the following components:
Sods on each property wifi be tested prior to any action.
B. If testing of the hazards associated with construction at a vacant contaminated lot in
Midvale shows that relocation is advised, because the National Air Quality Standards may
be violated, residents will be offered relocation during construction activities.
C. Removal of contaminated household dust from residences when lead concentrations in the
dust are above 500 ppm lead using field analysis.
D. Removal of existing garden sods down to 1 8 inches for soils with concentrations of lead
greater than 200 ppm and arsenic greater than 70 ppm. Institutional controls wlU be
employed to regulate the installation of new gardens.
E. Removal of contaminated sods, not covered by pavement or structures, contarung
concentrations greater than 500 ppm Pb and 70 ppm As. The depth of excavation, based
on data gathered during the 0U2 RI is not expected to exceed 24 inches.
F. Replacement of excavated areas with clean I upto the ori nal grade.
G. Revegetation to initial concitions.
H. Temporary storage of contaminated soils at OU 1, separate from the ta ngs arid where
they w be induded in the nal remedy for OUI.
I Installation of a plastic ner under and over the excavated soil which w be stored at
OUI. This liner w prevent recispersal of the sods before remedation of OUI.
J. Institutional controls to require builcing permits pnor to construction during removal or
replacement of pavements or foundations. Such activities may expose contaminated sods
left in place by remedation and such activities w require special precautions. A
cthzens repository may be created to provide a place for residents to depose of soils
during these future activities.
17
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K Detaled descriptions of institutional controls wdl be produced during RD. and they w
be enacted by the appropriate local governments prior to implementation of R&
The objecthie of the selected remedy is reduction of exposure of the residents of Midvale to
the unacceptably high levels of lead and arsenic In their sods. The action levels based on
health-based calculations are 500 ppm lead and 70 ppm arsenic for sods. Because home grown
vegetables grown in contaminated sod can incorporate lead and thereby produce an ad tionaJ
exposure route, the action level for garden soils is 200 ppm lead and 70 ppm arsenic. When
this remedy is implemented, thç risks from cancer due to arsenic exposure will be reduced
from current risks of 5 x 1 0 to 2.6 x 1 the current hazard index due to arsenic exposure
will be reduced from 2 to 0.44. The percentage of children precicted to have blood lead
levels in excess of 10 ug/d will be reduced from 85% to approximately 11% in areas of
greatest contamination. In areas of intermedate contamination, the percentage will be
reducedfrom36%to 11%.
10. STATLT ORY D TERMNA11ONS
Protection of Humai Health aid th En*onment
The selected remedy meets the three goals for human health concerns to the maximum extent
practicable: (1) it wW reduce the blood lead level for most children 10 ug/d.. or less; (2) it
reduces the risk of cancer due to arsenic exposure to 2.6 x i0 5 , within the acceptable risk
range; and (3) it reduces the chronic daly intake/reference dose for arsenic to 0.44, a value
below the EPA goal of 1. The preferred goal of 10-6 excess risk of cancer due to arsenic
exposure could not be reached at this Site because the concentration of arsenic in local
background soils resi.dted in a s ghtly higher risk. Nonetheless, the risk does fall into the
acceptable range for arsenic and meets the other goals.
In adcition, short-term effects wm be minimized during remedal action because, during the
excavation process, the residents w be temporarily relocated if necessary and f 4tive dust
controls during transport of contaminated soils will be implemented. Therefore, there will be
no unacceptable short-term risks or cross-meda impacts caused by implementation of the
selected remedy.
Compi ice with ARARs
The selected remedy w comply with all Federal and State ARARS. A llst of ARARs for the
selected remedy is gven in Table 8. Because the remedy involves excavation of contaminated
soils from 0U2 and placement of them into OU 1, the ARARs affecting OU I must be
considered. Where Utah is authorized to implement Federal law, Federal standards have the
force of Utah Law as wet
Cost Effectiveness
Of the two remecles in which the contaminated sods are transported away from the residences
in 0U2, the selected remedy is the most cost effective while still provdng an equal level of
protectiveness. It also compares favorably with alternatives where the wastes remain on Site.
18
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ThRLE 1
cOMPARATIVE ANALYSIS or P 1MM. ALTERNATIVES
Alternative I
Criteria No Action
Altern.ttv. 2
Capping
Alternative 3
SoiL R.movat/
Replacement
Alternative 4
In Situ
Stabilisatlon
? lt.rnativ. S
Soil Washing
OVERALL PROTECTIVENESS
Hu.an Health No significant Cap r.ducea direct Removal of Imaobillcstion of R..ovaL of
reduction in risk contact with contaminated soil ..tals reduca. risk cont..rnat.d soil and
contaminant r.duce. risk of of direct contact regulated disposal
dic.ct contact r.duc.s risk of
direct contact
Environmental Allows continu.d Spread of Migration pot.ntial Migration potential S.. Alternative 3
Protection spread of contamination •ini.ised du. to .ini.as.d due to
conta.ination curtailed by cap, and r.moval of accessible atsbilialng of
v.g.tation layer contamination acc.aaible
contaminstion
COMPLIANCE W/ARARS
themical Specific ARAR Does not me.t air or Mr and water S.. Alternative 2 S.. Mt.rnative 2 S.. Alternative 2
water release protection .tandsrda
standards ace sot
Location Specific ARAR Not relevant S.. AlternatiVe 1 OperabLe Unit I S.. Alternative 1 S.. Alternative 3
location specific
ABARS will be met
Action Specific ARAR Would not melt ARABs Ml Iedsral and State See Altarnative 2 See Alt.cnatlve 2 See kltecnativ. 2
regulations are set
by procedures
incorporated during
r...diat Ion
Other Criteria/Guidance Allows soil Prot.cts against soil See Alternative 2 5.. Alternative 2 See Alternative 2
inq.station exceeding ingestion to 500
500 mg/kg Pb mg/Kg lead
Wt TERN LUECTIVENESS
& PERMANENCE
Magnitud. of Source baa not been U .sidual risk from Residual risk from Residual risk from See Alternative 3
Residual Risk Removed. Eristing potential breach in contaminant below contamination below
risk will remain, cap eiti.ting barriers etabiligad soil
Adequacy and No control, over Integrity of imported Institutional Institutional See Alternative 3
Reliability of Controls remaining soil layer will b. controls are d.siqn.d constrois are
contamination maintained by to prevent esposure designed to prevent
institutional control to contamination espo.ure to
measures. below esisting stabilig.d atid
Reliability barriers - contaminated o1ls.
questionable. Reliability
queationable.
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TABLE 7 cont.l
1 COIUMMIvE ANALYSIS 0? P1MM. ALTCIQUi TIVE5
Alternative 1
Alt.rnstjv. 2
Alternative 3
Soil R..ovaj/
Alt.rn.tive
In Situ
4
Alternative S
Criteria No Action
Capping
Replacement
Stabilisation
Soil
Washing
REWC ’rloN 0? TOXICITY,
It BIUTY . VOUJH
Tr.at..nt Proc.s. 11usd None Non, used 3. 3b — None used 1 ..ical and physical Contamination
3c — to b. determined tsbilitstion of extracted fro. soil
conta.insnts to solution
Amount D..troyed or lion. Non. None 24200 CT 242.000 C V
Tr.at.d
Reduction of Toxicity, lions No reduction in 3. 3b, — No Nobility prevented by Highly conta.inst.d
Mobility or Volume volume or toxicity, reduction in volume Incorporation into volume reduced to
Nobility reduced by or touicity. Nobility .011 matrix. Volume 2,000 CV. Mobility
cap reduced by disposal incr.ss.d. Toxicity and toxicity of soil.
location controls, decreased. ar. reduced.
3c — to be detersined
Irr.v.reibl. Treatment Hone No tr.st..nt used 3m 3b — No tresta.nt Initially Irreversible
used irreversible, long
Sc — to be determined te&-a unkno,m.
Typ. and Quantity of 110 treatment used S.. Alternative 1 3., 3b — See 280,000 CV of 240,000 CV washed
Residuals remaining ‘ther.for. no klternstiv. 1 stabili,.d soil soil and 2,000 CV of
after treatment r.siduaLa remain. 3c — to be det.r.ined metal sludge
Statuatory Preference boee not satisfy See Alternative 1 See Alternative 1 Satisfies See Alternative 4
for Treatment
SHORT TERM
CFFCCPIVLNESS
Coinity Protection Rick not increased by Re.idents relocated See Alternative 2 See Alternative 2 See Alternative 2
ru.dy i l..entation during i.plementation
Worker Protection No risk to workers Leas risk because Level C protection See Alternative 3 See Alternative 3
minimal dust required.
generated, however
Level C protection
r.qui rid.
Environmental Impacts Continued impact from Duat generated during See Alternative 2 See Alternative 2 See Alternative 2
existing conditions construction
Time Until Action is H/A 3 1/2 years 3 1/2 years 3 1/2 years 3 1/2 years
Complete
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TADLS 7 (cent.)
C PARATIVE ANALYSIS OF FINAL ?ILTSRNATIVSS
Iilt.rnativs 1
Crit.ria No Action
?dt.rnativs 2
Capping
klt.rnativ. 3
Soil 9.moval/
R.placu.nt
klt.rn.tiv. 4
In Sktu
Stabilization
AJt.rnativ. S
Soil Washing
I1 WW 11TAULITY
Lass of additionaL
r..adlation if n..d.d
Ability to Monitor
Lttsct iv.na.s
Ability to obtains
approval from oth.r
ag.nci.i
If monitoring
indicatsa mon action
is n.c.ssary, FS/ROD
procsa. say n..d to
b. dons again.
Soil monitoring will
indicat. incr.a.ing
contamination
Standard construction
t.chniquss r.quii.d
to oper.t. and
construct.
Ground wat.r
monitoring will jivs
notics of failurs
b.fors significant
.spoaun. occuru
Klni.al coordination
with local, stats and
f.d.ral aganciss
ns.dsd
Modarats lsv.L of
coordination with
local, stats and
f.d.ral ag.nci.s
n..dsd
T.chno logy rsad.t ly
availab I. to
construct and op.rat.
stabilization proc.ae
T.chnology r.adily
availabls to
construct and op.rats
washing proc...
High l.v.1 of
coordination with
local, siSt., and
f.d.ral ag.nci..
n..d.d
Availability of Ho ..nvicss or
S.cvlcsS and Capaclti.s capacitiss n.quirsd
Availability of Non. c.quir.d
Cqutp.snt. Sp.ctaliats.
it. t .n a La
Availability TachnolOgy Non. rsqutn.d
COST
S.. klt.rnativ. 2 Disposal capaciti..
to b. d.t.rmin.d
S.. ?..lt.rnativ. 2 Sp.ciaiiu.d .quipmsnt
ava ilab l.
5.. ALt.rnativ. 3 S.. A.ltsrnativ. 3
Ability to Construct
and Op.rats
No construction or
op.nation r.quirsd
Would d.stroy
original r.msdy
S.. klt.rnativ. 2
S.. Mt.rnativ. 2
S.. Alt.rnstiv. 2
No approval n.c.asary
S. 1lt.rnativ. 2
S.s Mt.rnativ. 2
S.. Mt.rnativ. 2
S.. Alt.rn.tiv. 2
S.. Mtsrnativs 3
Diaposal not r.quir.d Disposal capacity
availab l.
Typical construction S.. Alt.rnativ. 2
.quip.flt. ..at.rial,
.p.claltst n..d.d
Cap t.chnology R.quir.d t.chnology
r.adily availabi. r.adiiy availabis
a 97.340,000
b 72,190,000
c 21,910,000
72,000
a 90,000,000
b 73,230,000
c 22,650,000
Capital
150,000
16.680.000
First Ysar
Annual
0tH
Coat
120,000
78,000
Pr.sant Wotth Cost
1,300,000
17.483,000
24.010,000
78,000
24,833.000
91,520,000
72,000
92,260,000
,‘-
-------
TABLE 7 icont.)
C IPARATIVE ANALYSIS or rINAL ? L1TRW1IVES
Ccit.ria
klt.rnstiv. 1
No Action
klt.rn.tiv. 2
Capping
kit.rn.tjv. 3
Soil Re.ovsl/
Replac ..snt
kltsrnatjv. 4
In Situ
Stabilisation
Mt.rn.tjv. S
Soil Waahing
STA AC PTANCE
Not pr.t.rr.d
Not pr.f.rr.d
Pr.t.rr.d •lt.rnstiv.
Not
pr.f.rr.d
Hot
pr.f.rrsd
coit nu Y ACCEPTANCC
Minor faction
supports
Not prsfsrr.d
Major support of
r..id.nts and
political l.ad.r .hip.
So .. r.proc.ssora
•xpr.s..d conc.rn.
that naturs of soils
with tailing. •&ght
pr.s.nt probi.., for
r.proc.s.ing option.
at OU I.
Not
pr.f.rr.d
Not
pr.f.rr.d
-------
Sharon Steel/Midvale Tailings Site Mining Waste NPL Site Summary Report
Reference S
Meeting Notes Concerning Sharon Steel/Midvale Tailings Site;
From Laurie Lamb, SAIC, to Sam Vance, EPA Region VIII;
March 26, 1991
-------
MEETING
SUMMARY REPORT
SAIC Contact: Laurie Lamb Date: 3/26191 Time: 8:00 a.m.
MeetingatSAlC X MeetingatEPA
Person(s) Contacted (Organization): Sam Vance, EPA Region VIII Remedial Project Manager
Subject: Sharon SteellMidvale Tailings Clean-up
Summary: Overall, Sam felt the NPL Site Summary for Sharon Steel was well written. It was simply
lacking the most updated information for the site.
Operable Unit 1 has a new Remedial Investigation/Feasibility Study and Proposed Plan which came out
in October. (Perhaps that’s why it didn’t make it into our document?) The Proposed Plan is
significantly different than the one proposed in 1989. The ground-water Addendum Remedial
Investigation is approximately 1,800 pages - this document (study) provided a better understanding of
the site hydrology.
The State is leading the Remedial Design for Operable Unit 2 with incremental funding from EPA. A
draft Remedial Design work plan is expected by May. The final is expected at the end of May.
A ROD for Operable Unit 1 should be out in December 1991. The tailings reprocessing study is ongoing
at the Salt Lake, Spokane, and Rolla offices of the U.S. Bureau of Mines.
-------
Sharon SteellMidvale Tailings Site Mining Waste NPL Site Summary Report
Reference 6
Excerpts From Report of the Preliminary AssessmenUSite Inspection
of Sharon Steel Corp.; Prepared for EPA by Pat lanni, Ecology and Environment,
Field Investigation Team;
March, 15, 1983
/
-------
Cc,1 0313
ADMINISi ATIVE RECORD
SF FILE NUMBER
‘.4.
REFORT ON THE
PR D-tLN RY ssEss’. r /S1Th Th SPECTI
OF
SHARON STEEL CORP.
TDD NO.R8-8301-03
Sub tted to: 1
-------
CO1 0915
SHARON STEEL CORPORATION SI I .
Sharon Steel Corporation owns 260 acres of land occupied by an
old smelting/milling operation and several tailings ponds. This
property is located in Midvale, Utah just south of 7800 South Street.
Bordering the site is a railroad track, part of the Denver and Rio
Grande Western Line, along the northeast side, and 700 West Street
along the southeast side. The Jordan River flows along the south and
west boundaries.
The site was orginally owned and operated by U. S. Smelting
(later known as U. S. Smelting, Refining and Mining Company) from
approximately 1910 until 1971. The smelter was shut down in 1958 and
the mill ceased operations in 1971. U. V. Smelting purchased U. S.
Smelting in 1971 and also operated a smelter on the north side of 7800
South Street. In 1979, Sharon Steel purchased the land south of 7800
South Street. The northern parcel, containing black slag piles from
the former smelting operation, was sold to Material Services, Inc.
The original on—site operations involved receiving lead, copper
and zinc ores, extracting the sulfide concentrate of these metals, and
then smelting these concentrates to extract the metals in a purer
form. The primary source of the ores was the Lark Mine in Lark, Utah.
The facility also operated as a custom mill, receiving ores from many
sources and extracting a variety of metals. Thus, the wastes (mill
tailings) produced varied depending on the specific ores and refining
processes used. The wastes were disposed on-site in flotation ponds
located to the south and west of the mill. Sharon Steel purchased the
site with the intention of reclaiming precious metals from the mill
tailings. however, their only activity to date has been selling yr1te
concentrate) which is stored on-site. Currently, ten million tons of
tailings, approximately 40 to 50 feet deep in places, are piled
on—site.
An environmental/health problem was first detected in June,
1982, when thejitah State Department of Health was notified that
citizens were gathering i d—blOwfl mill tailings along the 7800 Sou i
Street right f-waY , and using them for sand boxes, gardens, et:.
this time,- he State analyzed a sample of the “sand whic’i had Efl
removed by a citizen and found it contained 4000 pp 1ea . In
14
-------
Sharon Steel/Midvale Tailings Site Mining Waste NPL Site Summary Report
Reference 7
Excerpts From Potential Hazardous Waste Site Identification
and Preliminary Assessment, Sharon Steel Corporation;
Prepared for EPA by Ecology and Environment, Field Investigation Team;
March 14, 1983
-------
WASTE SITE
/4. AND PRELIMIP4ARY ASSESSMENT
NOTE. This fer is compl .t .e I waste in. to help set priorities for site inspection. The In(orm.uo
subuntited Ihi f Is baud on available reccrds and may be updated on subsequent forms as a resiaft of additional inqulnes
and oe..hte enspectiona.
GENERAL INSTRUCTIONS Complete Section, and III threugl I as Completely as pOssibI before
4.... . ,,.nt ). File this form in the Regional Hszardous Wait. Log Fil, and submit a copy to U .S. Envi ,enm.ntai Protecti
Agency; Site Tracking Syst.m; Hazardous Wait. Enforcement Task Force (EN.335 401 M St., SW; Washington DC 20460.
____________________________ 1. SITE IDENTIFICATION
A. SITE WAM( STREET (or oh.,
Shcirr,i S kQj Cdrpr 4ho.l 7OO t J +
0. STATE C. ZIP CODE I F COUNTY NAME
C. CITY ( I 5 I Jo La I
C. OWNER/OPERATOR (I I k,ioen)
I. MAM 2. TCLEDi Op g NU StR
J ’ 1 y” - ‘- - I 8o;- 3 5—53o
N. TYPE OF OWNERSHIP
Dt. FEDERAL 2. STATE 3 COUNTY 4. MUNICIPAL 5. PRIVATE Ds u wow,
I. SITE DESCRIPTION
v .Ils.j/S tt ’ r hc.., a. d*3p aai a” .c 4 4...— 6 1 C ,dC 1/oh .- —
u C c.- ,., I o —
J. 40W IOCWTIFI b (1... cUSs... coOVIainta. OSHA CSi ationI. lIe.) . DATE IOENTIFIEO —
I -t- “tid I . ‘ c l (me.. day, a yr.)
I
I .. PRINCIPAL STATE CONTACT
I. N*M 2. T( (P g NU gR
/b La I
e ’—
II. PRELIMINARY
ASSES$MENT(campgct . section last)
A. 4P AflFNT SERIOUSME OF PRO9LEI4
I HIGIq Z. MEDIUM 03. LOW NONE Os. UN MOwN
9. RECOMMENDATION
:
I. NO ACTION NEEDED (no ha ,ard) 02. IMMEDIATE SITE INSPECTION NEEDED
a. YCNYATIVg V SCNgDU gQ CO.
3. SITE INSPECTION . f , ‘t4ij L td:
a. TENTA?.Vg ScHEDULeD COR b. WILL as PERF .)RMLO av
b. WILL. s PCRrOSWED Sr
— 4. SITC INSPECTION NEEDED (toe Pliorily)
1 dlII ‘ htr
.- i R i t 1s n C 2 C,. j
C. PREPARER INFORMATION
I. NAME 2. TELEPHONE NU SER I. DATE (mc.. day.Ayr.)
P /Mar J
I
3—N -
ill.
A. SITE STATUS
0 t. ACTIVE (The.. in . .j.i 2. INACTIVE (Th... OTHER (ap .cSIp .):_____________________________
aiinuicipaj air.. .*Sch . b.Sn va. a 1•• w*ich ma Iontar .IPcai..j a. air.. hal inclwda audi ‘Acid.,,. Ilk. msd .s hi d ,ipln 5
10, Wa.,. IVamas , . Waal*a.)
o n a ‘ ..ç,,,,. no r.uIa, 0 COAIIAWA 1 ea.ot th. aSs. So. waai. diap.. a1 ha. occwv.d.)
qvanI Iy.)
1 11 (i E. Ikd o.m-s .,k.
S. IS GENERATOR ON SITE?
I. NO 02. YES (apcilp amao..,o,.. too. di4Ss SIC C.d.).
No r t --& ‘n r 4or -1c#-- 1’Uo —I(li,
C. AREA O
SITE (in
LO
aa..)
-
0. IF AP
I. LATIT
PARENT SERIOUSNESS OF
UOI (d• .—Pbi._..C,)
SITE IS HIGH. SP
a.
I
£Cip’ ’ COORDINATES
LONSITUOS (d.g... .iin....aac.)
—
OC 1 086
i GION SITE NUMSER (I. b•
I s
C. ARE THERE SLJILOINGS ON THE SIT!?
.01. NO 3. YtS(.P.ciI ?.) off t .c. , null O?e hcn3(Scutr I rt 4frJ-Ic,I, (C.C _ Clvii. j ( i . )
T2070..2 (lO..7 ) G O
. .D
-------
VII. PERMIT INFORMATION
APPLICABLE PEPUITS sILO BY THE SITE.
cc l
0(5 PERMIT
AIR PERMITS
7 RCRA STORER
02 SPCCPL.AN
0 S. LOCAL PERMIT
0 a. RCRA TREATER
0 3. STAY ( PCRMIT(.p.cgIy).
0 ACRA TPAN$POR7
PC A O’SPOSER
0 tO OTHER (.p.CS1?)
3 IN COMPLIANCE?
0 I. v s 0 2. NO 0 3. UNKNOWN
4. WITH RESPECT TO (11.1 ,. uIatton .ø,• è
VI I I. PAST REGULATORY ACTIONS
0 A NONE B. YES (.ur u .rèi . b .J.)
- I-) -9 *, .. . c c pks
IX. INSPECTION ACTIVITY (past or onaolngj
1 0 A. NONE B. ‘TES (copl .t . ,.,. 1.2.3. A 4 b .So)
I TYPE O ACTIVITY
2 OATS O
PAST ACTION
( ‘to.. d.y . A yr.)
$ PER OR 5D
SY
(EPA/Sea’.)
4. OESCRIPTION
? ‘v c $ sc,s. . 4 ./
2 .-I -Q
€.i€ FrT ‘
.
S/IS JC& I?CI: .i7C1v,
X. REM
EDIAL ACTIVITY
(past or ors-aoina)
A. NONE 0 B. YE5(c pJ.e . St.. ,. ),
2.3. A 4b.io)
I. TYPE OY ACTIVITY
2. OATS 0
PAST ACTION
(‘tO.. d. . & it.)
S. PERPORMED
SY
(EPA/SS.t.)
4 DESCRIPTION
NOTE: Based on the isformataon in Sections III through A, il1 out the Preliminary Assessment (Section II)
information on the first page of this form.
EPA F’t— T2070-2 (10.79)
PAGE 40F 4
-------
Sharon Steel/Midvale Tailings Site Mining Waste NPL Site Summary Report
Reference 8
Excerpts From Proposed Plan for the Mill Site, Operable Unit No. 1,
Sharon Steel Site, Midvale, Utah; EPA Region VIII; October 1990
-------
U.S. EPA Fact Sheet
October 1990
Proposed Plan for the Mill Site
Operable Unit No. I
Sharon Steel Site
Midvale, Utah
EPA ANNOUNCES PREFERRED ALTERNATIVE FOR THE MILL SiTE AND TAILINGS J
The U.S. Environmental Protection Agency (EPA) has
announced its preferred alternative to address contarnina-
tion of tailings 1 and ground water at the Sharon SteeU
Midvaie Tailings Superfund site (Sharon Steel site) in Mid-
vale, Utah. EPA is the lead agency for the cleanup at the
site.
The preferred remedy for the mill site (Operable
Unit 1) is to implement Alternative No.4, capping with
ground water treatment However, EPA will also estsbiish
a process to continue evaluating reprocessing as a pcten-
tiai remedy. EPA will continue dust suppression activities
until final implementation of a remedy is initiated. For more
details about this alternative, see page 8.
The Proposed PIan - -
This Plan presents EPA’s preferr alternative for
remedianng Operable Unft 1 (OU1) atthe Sharon Steel site.
It includes the mill site, surrounding tailings, and con-
taminated residential soils (from 0U2) that EPA plans to
incorporate into the mill site remedy.. . . .. .. -
— -.— .—. .. ——-—- -‘i— — :
MARK YOUR CALENDAR: OPPORTUNmES FOR PUBLIC INVOLVEMENTS
Public Meeting
January 9. 1991. 7:00 p.m.
Midvale Middle School
138 Pioneer Street
Midvale, Utah 84047
Public Comment Period
October 9, 1990 January 15. 1991
Send commerite to
Sam sice. Remedial Project Manager
U.S. Environmeri i Protection Agency
999 18th Street
Denver Colorado 80202
Record of Decision
March 31, 1991
Information Repositories
The Proposed Plan, the Remedial hnestlgatlon and Feasi-
bility Study (RL’ S) reporte, and other documents in the
Admin,strative Recoid ate available st inform on repositones
at the following Ioc cns (see next column):
Ruth Vine Tyler Library
315 Wood Street
Midvale, Utah 84047
Hours Mon-Thurs: 9:00 arn-9:00 pm
Fn-S 9:00 am-5:30 pm
City of Midvale
City Hail
80 East Center Street
Midvale, Utah 84047
Hours: Mon-Fn: 8:00 am-5:00 pm
Utah Department of Health
Bureau of Environmental Response and Reme anon
288 North 1460 West Fourth Floor
Salt Lah City, Utah 84116
Hours: Mon-Fri: 8:00 am-5:00 pm
EPA Superfund Records Center
999 18th Street
Derivei Colorado 80202
Hours: Mon-Fn: 8:30 am430 pm
‘Wor s shown in bold italics ot the first mention are defined in the glossary at the end of this Proposed Plan.
PPINT ON RE ”C ‘APER
\
-------
PUBLIC INVOLVEMENT PROCESS
Residents arid other interested parties are encouraged
This Proposed Plan is prepared in fulfillment of E
to read and comment on this Proposed Plan and the
public participation responsibilities unaer Section 117
Remediai Investigation and Feasibility Study (Rl/FS)
of the Comprehensive Environmental Response, Cc
Reports. prepared by EPA in cooperation with the Utah
Department of Health (UDOH). These documents
pensation, and Liability Act (CERCLA) of 1980.
amended by the Superfund Amendments and Reauth
desCrloe site conditions and all the cleanup alternatives
izatlon Act (SARA) of 1986.
considered during studies conducted at the mill site.
EPA will make its final selection of an alternative only
after considenng State arid community comments. EPA
may modify the preferred alternative, select another
alternative presented in this plan, or select a more ap.
propnate alternative based on new information or public
comments. Therefore, the public is encouraged to
review and comment on all the alternatives identified
Comments on the Proposed Plan and FS Rep
may be submitted either orally or in writing at t
here, as well as to provide any new information for
public meeting, or you can send EPA wntten Co
EPA’s consideration. More detailed information on all
merits postmarked no later than January 15, igS
the alternatives can be found in the Mill Site Feasibility
Study (FS) Report. By March 31, 1991, EPA will publish
a Record of Decision (ROD) that responds to State and
community comments and documents the rationale for
its decision. This will be the second ROD for the site.
The first ROD was issued on September 24, 1990 and
addressed contaminated residential soils, Operable
Unit 2 (OLJ2).
—_ -__ .— . -, -.. . —- - — , .. - . —-- . - - .
- .- - - - — -. - —. - _.nc - — - -- - - - S Th. - - - — - — - - —
-- - . - - - This Proposed Plan Covers - i
— — _ _ . — __ — — — — _. • ——— ?
- - — . ,_ _— - ‘- -
- - - - .. .- - —— - .1 — - -—— _ ,.. . - -. - , - - - .-- -
- Site Background -:
— - — —.. — — t .... — - —. :.—..-
RiskEvaluations . . .;. -- - . p 4:f —
- - Cleanup Evaluation Critena . .. . - - .. . - ... . . . p. 5 - -.
Summary of Alternatives . p. 5
Preferred Alternative -.. - .. -. p.6
Comparison of Alternatives p. 7
Reprocessing - ... .... p. 8
Glossary p.9
.2.
-------
Sharon Steel/Midvale Tailings Site Mining Waste NPL Site Summary Report
Reference 9
Excerpts From Remedial Investigation Addendum
for Sharon SteelfMidvale Tailings Site, Midvale, Utah,
1989-1990 Ground-water/Geochemistry Data Report;
Prepared for EPA by Camp, Dresser & McKee;
Undated
-------
REMEDIAL PLANNING ACTIVITIES AT
SELECTED UNCONTROLLED HAZARDOUS
SUBSTANCES DISPOSAL SITES IN A ZONE
FOR EPA REGINS VI, VU, & vru
U S EPA CONTRACT NO. 68-W9-0021
REMEDIAL INVESTIGATION ADDENDUM FOR
SHARON STEEL/MID VALE TAILINGS SITE
MID VALE. UTAH
1989-1990 GROU SD WATERJGEOCHEMISTRy
DATA REPORT
VOLUME I - TEXT
Work Assignment No. 003-8L40
Document Control No. 7760 -003-RI-BLRT
Prepared for:
U S Environmental Protection Agency
Prepared by
CDM Federal Programs Corporanon
8215 Melrose , Suite 110
Lenexa, KS 66214
-------
EXECUTIVE SUMMARY
Editor’s Note: This Executive Swnmar% provides a general overview of the Remedial Investigation
Addendum. The reader should note that, in szmp1 fyrng the language and generalizing the conclusions
for this summary, nuances tha are important to the scientific reader are lost. For this reason, the
body of this report is written for the scientific communiry and should be consulted by those readers If
an)’ confission between the content of this summary and the content of the final Remedial Investigation
Addendum is apparent, the confusion is interpreted in accordance with the report.
1.0 INTRODUCTION
The Sharon Steel/Midvale Tailings Superfund Site (the Size) is located in Midvale, Utah,
approximately 12 miles south of Salt Lake City The study area includes: the Sharon Steel mill
tailings. agricultural lands that lie to the west and south of the mill site, the southwest portion of the
Midvale community, and wetlands located to the south and east of the mill tailings pile
The Sharon Steel/Midvale Tailings Site has been divided into two Operable Units by the
Environmental Protection Agency (EPA) Operable Unit One (OU1) is the Sharon Steel property,
which includes the mill buildings. wetlands and tailings piles. These features were used to define the
site boundary during nomination for placement on EPA’s National Priorities List (NPL) as a
Superfund site. Operable Unit Two (0U2) includes the residential and high public use areas in
Midvale adjacent to the Sharon Steel property. 0U2 boundaries were first defined by the EPA in
1988, but have been revised based on the additional sampling described in the 1990 Soils Remedial
Investigation (RI) Addendum, and in the Feasibility Study (FS) for Operable Unit Two (see Volume
III of the FS). The site was officially listed on the NPL in August 1990.
The 1990 Remedial Investigation Addendurns (Soil and Ground Water/Geochemistry) and Feasibilit
Study were conducted by the EPA in response to a request by local citizens and officials from the
local and State governments for a study which had more detail than the 1988 RI and FS conducted b
EPA. This report presents the results of the additional ground water, ground water geochemistry, ar.d
subsurface soils chemistry studies conducted in and near the community of Midvale, Utah from
-------
November 1989 through May 1990. The primary objectives of the ground water/geochemistry
investigation are:
• To further describe the ground water system underneath the Sharon Steel/Midvale
Tailings Site.
• To further describe ground water quality at the site and the extent of ground water
contamination.
• To use the above information to predict the movement of contaminants, particularly
arsenic, in the ground water system beneath OU I.
Figure ES-i conceptually depicts the site and lists the major objectives for the ground water and
geochemistry studies. To describe these studies, the report is divided into four sections:
Introduction, Methodology, Results and Interpretation, and Summary of Results. In addition, several
data appendices are included which contain results of analyses and supporting data developed during
the course of the investigation.
Several previous field studies have been conducted at the site (including EPA ’s 1988 RI); data and
information from these studies have been incorporated in the current study and reported herein.
2.0 METHODOLOGY
EPA is required to document the methods and procedures to be used in data gathering prior to the
field study. Often the methods are modified or changed in the field because on-site conditions are
found to be different than expected. The methodology section describes the procedures that were
actually used in the study.
Sixteen wells were completed to evaluate the soils and tailings of the Site study area during this
investigation. The purpose of the wells was to determine subsurface geology, to provide a monitoring
device for recording changes in ground water levels, and to obtain subsurface soils and ground water
samples for chemical analysis. The wells were drilled and completed in a manner to preclude any
cross-contamination between foreign substances and the soil and water in the drilled hole and
subsequently completed well.
7
-------
I
I
1E IFA
1 )MY—9O ;t
tiDY INCLUL)ID:
,
:iiI li l;(IIIIi W\U I
ONJAMINAJ
LI) GROIJND
WAT [ I [ J !1LW Y
MI
OFISIIF)
‘
I’
i
I / UI lI( ’. WI I I IIlIi
IJ ,.‘ s ,) ‘ ‘I Ill I 1.’
III .‘ ‘iii ‘i i wi i i.
NW
N —
RI / [ R
SlAG (Sill
IJOUNOARY OR 1/4
I Ni — -— OAK ST Wit
INCIUASE 0 I UMF’ING I.
i
IF [ CIS — Mi [ )VAI II
WIlLS
‘
• ‘
‘
WI I I I 1 Ml Ii’ I •. Iii ut Iii
“I .1 WI II I J I 1.1 ‘ . wi Ii i
I I_JlII,•! Al
LJIIIbI i\IlI P IiIi ‘,i /’/i I
j i.I Jj I I•
I(IIiIII)/ I , IIII J II .” i
I 1( I I t .11 II 1t II ‘II h
Figure ES-i - Ground Water/Geochemistry Study Summary
,1
-‘
/
“/4 /
i_I_• .1 II I lii i
(‘flia
-------
Subsurface geology was determined by geologists present during the well drilling. The on-site
geologist described the subsurface soils as they were extracted from the drill hole. Later, geologic
logs for each hole were written and compiled into a geologic cross-section which represented the
subsurface geology of the site.
Subsurface soils extracted from the drill holes were recorded and sent to storage; some samples were
divided, with portions sent to EPA-approved laboratories for both chemical and physical analyses.
Extreme care was taken to ensure that the soils were representative of subsurface conditions and were
not cross-contaminated by foreign substances.
When the target depth for a particular hole was reached, the drill tools were removed and the hole
was completed as a monitoring well Upon completion, the well was developed by surging and
removing water until the well water quality stabilized.
Ground water levels were monitored periodically. The levels were measured using electronic devices
that were checked for accuracy. All monitoring devices were decontaminated before and after
placement in a well.
Ground water samples were obtained using pumps designed to extract water which were
representative of the ground water found at the well location. Care was taken to insure that the
sampling method did not influence the chemistry of the water.
A Quality Assurance (QA) program was conducted throughout the course of the study to ensure that
collected samples were representative of the site. The QA program included: collecting duplicate and
triplicate sample sets during the same sampling event; collecting samples (ground water) at the same
monitor well during different sampling events; and creating blank samples. These procedures allowed
the study team to evaluate the sampling program with respect to accuracy and precision of the results
A long-term aquifer test was performed on a well centrally located on the mill tailings. The purpose
of the test was to determine the hydraulic properties of the aquifer directly beneath the tailings. The
test was conducted for 14 days, seven days of pumping and observation and seven days of observation
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only. Water pumped from the well during the test was continually monitored for water quality to
ensure that no contaminants were distributed to the surface.
Laboratory, or analytical, methods were used to analyze both subsurface soil samples and ground
water samples collected during the investigation. The procedures used in the analyses were developed
for the EPA ’s Contract Lab Program (CLP), in order that the analyses provide the most accurate
results possible. In addition to the CL? analyses, analyses for stable and radioactive isotopes of
oxygen, hydrogen, and sulfur were performed by non-CL? laboratories These other laboratories
used procedures equally as rigorous as the CL? laboratory Quality Control (QC) programs were
required for all laboratories used in this study. QC programs are used to detect flaws in the anaiyti aJ
procedures so that the procedures can be amended and results of the analyses qualified
Understanding the interactions of soils with contaminated ground water can help determine the
ultimate fate of the contarninanon at the Site. Laboratory tests were performed by the U.S. Bureau of
Reclamation (USBR) Research Center in Denver, Colorado to determine the interactions between
arsenic-contaminated water from the tailings and noncontaminated subsurface soils found at the site
The laboratory tests entailed shaking a mixture of tailings water and subtailings soils together for an
extended period (batch tests) and percolating tailings water through the subtailings Loils (column
tests) The test procedures included precautionary measures intended to mimic conditions found at
the Site.
The data and results from the above analyses and studies were used in computer models which were
designed to aid EPA in determining the hydrologic and geochemical characteristics of the Sharon
Sceei/Midvafe Tailings Site These computer programs aided in determining such characteristics as
the amount of waxer flowing through the tailings pile and into the subsurface soils beneath; the
direction and speed with which the regional ground water flows around and under the site; the
chemical form which the arsenic takes in the tailings and subtailings water and soil, and finally, the
expected behavior of the arsenic contamination in the ground water beneath the site.
5
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3.0 RESULTS AND INTERPRETATIONS
3.1 HYDROGEOLOGIC INVESTIGATION
The aim of the hydrogeologic investigation at the Sharon Steel/Midvale Tailings Site was to determine
the subsurface geology, hydrology and geochemisny of the Site. The information gathered was used
to characterize the physical parameters of the aquifers of interest and the magnitude and direction of
ground water flow. These results, in turn, were used in the computer modeling of regional ground
water flow, and along with the results of the geochemical investigation, were used in the computer
modeling of contaminant transport in the ground water.
Four hydrologic units or aquifers at the Sharon Steel/Midvale Tailings Site are recognized: two
regionally extensive aquifers, the Deep Principal Aquifer and the Upper Sand and Gravel Aquifer,
which are similar in extent, composition, and depositional history; and two local aquifers, the Perched
Terrace Aquifer and the Saturated Tailings Zone.
The Deep Prir .ipal Aquifer is the main source of ground water in the Salt Lake Valley. The aquifer
is composed of clay, silt, sand, and gravel deposits resulting from erosion of the Wasatch Front The
Deep Principal Aquifer is generally unconfined along the perimeter of the valley, the recnarge area
for the aquifer In the central part of the valley the Deep Principal Aquifer is confined which causes
the aquifer to become artesian in this region. The confining layer consists of a relatively
impermeable deposit of clay, silt, and fine sand which ranges from 40 to 100 feet in thickness. The
confining layer at the Sharon Steel/Midvale Tailings Site is an effective barrier to the rapid exchange
of water between the Deep Principal Aquifer and the overlying Upper Sand and Gravel Aquifer.
Ground water flow in the Deep Principal Aquifer beneath the site is in a northeast direction.
The Upper Sand and Gravel Aquifer has a deposnional history and composition similar to the
underlying Deep Principal Aquifer. Ground water usage in this upper aquifer is primarily by small
domestic wells: however, in the study area some large volume public water supply wells pump water
from this aquifer. At the Sharon Steel Midvale Tailings Site, the Upper Sand and Gravel Aquifer is
overlain by the Perched Terrace Aquifer (described below) and the Saturated Tailings Zone (described
below). A discontinuous clay and silt layer, referred to in this report as the subtailings unit, separates
6
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the Upper Sand and Gravel Aquifer from the overlying tailings material. Ground water flow in this
aquifer beneath the site is in a northwest direction, with the Jordan River being a point of discharge
for the ground water.
The Perched Terrace Aquifer is composed of sediments that were deposited during a period of time
when the Salt Lake Valley was covered by ancient Lake Bonneville. These lake sediments are
comprised mainly of clay and silt with thin interbeds of fine sand. These sediments have been eroded
in the central portion of the Salt Lake Valley by the Jordan River and form a terrace above the river
Water from precipitation will, in general, percolate through sediments and into the underlying Upper
Sand and Gravel Aquifer; but sometimes, water will stop flowing and accumulate above an
impermeable layer, such as a clay layer This water is described as being perched. Some ground
water flow is into the Saturated Tailings Zone that lies in a lateral position to the Perched Terrace
Aquifer (see Figure ES-I).
The Saturated Tailings Zone, which currently contains water, consists of mill tailings deposited during
the refining operations of the Sharon Steel mill. Different types of ores were refined at the mill at
different times; therefore, the tailings produced were of varying composition and characteristics. In
general, the tailings are composed of fine grained sands and silts with interbeds of slimes (low
permeability deposits produced by the refining operations). Ground water flow in the Saturated
Tailings Zone is similar to the Perched Terrace Aquifer in that the water flows laterally and
downward into the Upper Sand and Gravel Aquifer, with some water remaining perched above the
slime layers.
3.2 OUALITY CONTROL AND OUALITY ASSURANCE (OA1OC) RESULTS
The results of QAIQC program for the study indicated that the sampling program provided samples
that were usable for purposes of supporting the investigative efforts. With few exceptions, the
sampling and laboratory analyses were consistent and reliable. The exceptions were not used in any
subsequent analyses.
7
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3.3 EVALUATION OF ANALYTICAL RESULTS
3.3.1 Subsurface Soils
Results from laboratory analyses of the subsurface soils showed that metal concentrations were highest
in the mill tailings, lower in the subtailings unit, and background levels in the Upper Sand and Gravel
Aquifer. It appears that the metals are being leached from the tailings by ground water percolating
downward. When the metal-laden ground water reaches the subtailings unit, the chemical conditions
found in that unit promote the precipitation of minerals that contain the metals and sulfur. Most of
the remaining metals will be adsorbed to the aquifer matrix or coprecipitate when the percolating
tailings water reaches the Upper Sand and Gravel Aquifer. An exception to this scenario is arsenic
Arsenic does not appear to precipitate as a mineral in the Upper Sand and Gravel Aquifer.
3.3.2 Ground Water
The chemistry of the ground water at the Site uniquely reflects the particular aquifer in which it is
found. As expected, the water in the Saturated Tailings Zone has high concentrations of metals,
including arsenic; furthermore, the water has high concentrations of total dissolved solids (TDS). The
ground water in the Upper Sand and Gravel Aquifer east-southeast (hydraulically upgradient) of the
Site and at depth beneath the tailings in the Upper Sand and Gravel Aquifer has no detectable
concentrations of arsenic and lower concentrations of TDS than in the Saturated Tailings Zone. The
ground water in the Upper Sand and Gravel Aquifer immediately beneath the tailings has detectable
concentrations of arsenic (over 200 parts per billion (ppb)) and TDS concentrations that are
intermediate to concentrations found in the tailings water and the ground water upgradient of the Site
and at depth beneath the tailings. The water chemistry of the ground water found beneath and in
close proximity to the tailings reflects that tailings water is mixing with ground water immediately
beneath the tailings, adversely affecting the water quality of the Upper Sand and Gravel Aquifer. Th
analyses of the stable isotopes of oxygen and hydrogen also reflect the mixing of tailings water and
ground water immediately beneath the tailings
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3.0 RESULTS AND INTERPRETATION
3.! HYDROGEOLOGY
3.1.1 REGIONAL HYDROGEOLOGY
The regional basin-wide ground water system in the Salt Lake Valley is an important water resource
to many users and consequently has been the subject of extensive study. References which have been
reviewed to gain insight into the relationship between the local hydrologic conditions observed at the
Sharon Steel/Midvale Tailings Site and the regional hydrologic system include Dames and Moore
(1988), Hely (1971), Jensen (1985). Kennecort (1984), Marine (1964), Miller (1980), Morrison
(1965), Taylor (1949), U.S.G.S. (1983b), and Waddell (1987a, 1987b)
The regional, basin-wide ground water system is generally characterized as consisting of two major
hydrogeologic units within the Quaternary age valley fill in the Salt Lake ValleyS the Shallow
Unconfined Aquifer and the Deep Principal Aquifer. These hydrogeologic units are separated by a
regionally extensive confining unit Within the regional system, the Shallow Unconfined Aquifer ts
described as being comprised of clay, silt, and fine sand and less than 50 feet in thickness. The
aquifer is generally reported to yield poor quality water slowly to wells The base of the Shallow
Unconfined Aquifer is marked by relatively impermeable deposits of clay, silt, and fine sand,
separating it from the confined, underlying Deep Principal Aquifer. The confining layer ranges from
40 to 100 feet in thickness and generally lies between 50 and 150 feet below the ground surface
(Hel , 1071).
The Deep Principal Aquifer is the main source of ground water produced by wells in the Salt Lake
Valley area. The aquifer consists of both an unconfined portion, generally located at the edges of the
valley near the mountain fronts, and a confined portion in the central part of the valley. Similar to
the Shallow Unconflned Aquifer, the matrix of the Deep Principal Aquifer is comprised of clay, silt.
sand, and gravel deposits (Hely. 1971)
Older Tertiary age deposits of claystone arid mudstone underlie the Deep Principal Aquifer. These
deposits consist of hard, sticky clay, clayey gravel, and thin interbeds of gravel (Dames and Moore.
1988). Although these materials are generally of lower permeability and yield, they are utilized
I
to
3-1
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locally for ground water production. Hely (1971) included these deposits with the Deep Principal
Aquifer for his studies. Other investigations have not included these materials with the Deep
Principal Aquifer because they are considered to be relatively impermeable when compared to the
overlying material (Dames and Moore. 1988). A review of well completion records from the studs
area shows that fewer wells have perforated zones within the underlying than overlying material
3.1.2 LOCAL HYDROGEOLOGIC SYSTEM
The local hydrogeologic system under investigation in this RI Addendum comprises a subset of the
basin-wide, regional system, briefly described in the previous section. The area! extent of the local
system includes the Sharon Steel/Midvale Tailings Site (the Site) itself in addition to that area within
an approximate two mile radius around the Site. Available data from well boring logs were used for
a fairly detailed conceptualization of the hydrogeology of the local system (see Plates 3.1-1 and 3 1-
2)
Site specific investigative activities were performed in areas both on and immediately adjacent to the
tailings site, providing more detailed hydrogeologic arid geochemical data than previously provided in
inc original RI (CDM 1998). These additional focused investigative activities allowed for further.
more detailed characterization and analysis of the local ground water system and provided a
conceptual model by which to predict potential impacts to the local system from the tailings site.
As a result of the additional efforts, an understanding of the geology and hydrog logy as previousl
described in the original RI is superseded by this discussion of the local hydrogeologic system.
Four separate ground water zones have been identified and differentiated at and in the vicinity of the
Sharon Sceel/Midvale Tailings Site: the Perched Terrace Aquifer, the Saturated Tailings Zone, the
Upper Sand and Gravel Aquifer and the Deep Principal Aquifer. The Perched Terrace Aquifer
occurs within the upper portion of the lacustrine deposits that underlie the terrace area east of the
tailings site. The Saturated Tailings Zone is comprised of saturated tailings in the old tailings dispos ;
area. Both the Perched Terrace Aquifer and the Saturated Tailings Zone are underlain by the Upper
Sand and Gravel Aquifer. In the original RI (CDM 1988), the Upper Sand and Gravel Aquifer was
called the Diastem Aquifer, but has been renamed for this document. As described for the regional
system, the Deep Principal Aquifer underlies the Upper Sand and Gravel Aquifer and is separated
3-2
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from it by a confining layer The following sections discuss the hydrogeologic characteristics of these
units in detail.
Plate 3.1-1 shows the location of wells utilized in the local hydrogeologic and stratigraphic analysis
A fence diagram shown on Plate 3 1-2 illustrates the areal and vertical relationship between these
units in the study area. This diagram was developed from driller’s logs of water wells on file with
the Utah Division of Water Rights (UDWR, 1986, UDWR, 1990b) Plate 3 1-3 depicts additional
detailed geologic cross sections of the Sharon Steel/Midvale Tailings Site.
Additional information concerning the hydrologic properties of these materials is also presented in
Sections 3.4 and 3.6.
3.1.2.1 Perched Terrace Aquifer
The Perched Terrace Aquifer occurs within the terrace on the east side of the Jordan River Valley
The terrace which abuts the east side of the mill tailings is comprised of native lake sediments
deposited in the ancestral Great Salt Lake The lake sediments consist of clay and silt with interbeds
of fine-grained sand. The log for borehole MW-401 provides a detailed lithologic description of this
unit (see Appendix B). Table 3 1-1 summarizes the results of geotechnical tests performed on
selected terrace materials from borehole MW-401. These tests show that clay/silt size material of lo
plasticity comprises all of the samples analyzed. Visual observations of the samples in MW-401
indicate that fine-grained sand and silty sand comprise some intervals. In some cases, the sand “as
thinly interbedded with the silt/clay materials. The thickness of these deposits range up to 67 4 feet
(MW-401) and 68.0 feet (MW-13) Thin remnants of the lake sediments are also present at some
locations on the margins of the Jordan River floodplain, ranging up to 5.7 feet in thickness (A02)
Fine- grained overbank deposits from the Jordan River also comprise portions of the Jordan River
floodplain.
Ground water within the lacustrine deposits is most commonly associated with the sandy interbeds
Five wells (MW-403, MW-404, OW-i, MW-i and 004) are completed in this unit. Logs from these
wells indicate that a high degree of stratification exists within the lake sediments. Figure 3.1-1 is a
hydrograph comparing water levels in wells MW-404, MW-403 and MW-402 which are completed in
a nested fashion into the ..shallow lake sediments, deep lake sediments, and Upper Sand and Gravel
0 ’
3-3
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Aquifer (immediately underlying the lake sediments), respectively. This figure illustrates the different
potentiometnc levels existing within different horizons of the lake sediments and the presence of a
downward hydraulic gradient. Available data indicate that ground water flow within this Perched
Terrace Aquifer is generally to the west, discharging to ground surface along the exposed vallevwall.
forming erosional flanks of the terrace materials or discharging into the mill tailings which abut the
terrace on the east side of the mill site. A minor component of discharge is also downward to the
Upper Sand and Gravel Aquifer to the extent permitted by the lacustrine clay/silt layers. Recharge of
the perched zone is reported to occur largely by infiltration of water from irrigation activities —
especially as a result of seepage from irrigation canals constructed within the lacustrine deposits
(Hely, 1971). Water level data (Figure 3.1-2) from well 004 shows a close correlation between the
presence of water in the adjacent Galena Canal and fluctuations in ground water levels. The
hydrograph for well MW-404 which is screened across the upper terrace materials (Figure 3.1-1) also
exhibits a rise in water table in May 1990 that could correspond with the onset of irrigation activities
Similar increases are also apparent in wells MW-I and OW-i.
3.1.2.2 Saturated Tailin2s Zone
The Saturated Tailings Zone is comprised of fine-grained, metalliferous sand and silty sand generated
by ore processing operations and deposited hydraulically into settling ponds constructed upon the
Jordan River channel and its adjacent floodplain. In the 1950s, the Jordan River was diverted to the
west to increase the area available for tailings disposal. Slime interbeds comprised of silty/clay
material are present in varying amounts throughout the tailings. Table 3.1-2 summarizes the results
of grain size analyses performed on tailings slime samples. The slimes consist of 80-100 percent
silt/clay fines of low plasticity. Previous analyses on the sandy fraction of the tailings (CDM, 1988)
show this fraction consists of 45 to 79 percent fine and very fine sand with 19 to 53 percent siWcla
fines. Coarser material comprises only Oto 5 percent of the material. Slime interbeds range from
less than 0.01 feet up to several feet in thickness.
The tailings range in thickness up to 61.6 feet (MW-752), depending upon the area of deposition.
Figure 3.1-3 provides an isopach map showing the tailings thickness over the Sharon Steel/Midvale
Tailings Sire. The base of the tailings generally lies between 4280 and 4290 feet elevation in the
Jordan River Valley. Figure4. 1-4 is a contour map showing the elevation of the base of the tailings
deposit.
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The tailings are usually underlain by organic-rich clay, silt, and fine sand representing overbank
deposits derived from the Jordan River Remnants of the lake sediments are believed to be present at
some locations along the valley margins where stiff clay/silt is found (well 004). Up to 6 1 feet
(MW-601) of subtailings material was encountered beneath the tailings. At some locations (SR.K-1O.
MW-200 series and MW-750 series wells) the tailings directly overlie the , indicating that these wells
may have intercepted the pre-1951 channel of the Jordan River. As detailed below, the subtailings
unit was penetrated by drilling at eight locations during the remedial investigations.
Subtailings
Thickness
Well(s) ( feet) Notes
001/AOl 3 9 Organic rich
002/A02 5 7 Upper 0.8 feet organic rich
003/A03 3 6 Sulfur odor, upper 1.7 feet organic rich
MW-201/202 0 Subtailings absent
MW-301/302 2.35 Organics near contact
MW-60 1 6 1 Sulfur odor, upper 0.6 feet organic rich
MW-751/752 0 Subtailings absent
SRX .10 0 Subtailings absent
In addition, 60 boreholes drilled during the reprocessing investigations (1MM, 1989) encountered this
subtailirigs horizon. Of these 60 boreholes, seven boreholes penetrated this horizon, indicating that at
locations A-3, B-3, B-7, B-9, B-13, B-l6. C-i, C-9, C-10, and C-18 the subtailings were apparently
absent. One of the areas ex.hibiting the lack of low permeability subt.ailings material was east of well
.1-03, and MW-601.
Table 3.1-3 summarizes the results of geotechnical tests performed on the floodplain deposits which
form the subtailings unit. In all cases, the materials tested were classified as clays, CL or CH,
according to the Unified Soil Classification System (USCS).
Ground water generally occurs in the lower portion of the tailings deposits. At some locations —
generally where the tailings deposit is thin — little or no ground water accumulation was observed
Thin zones of saturated materials were also observed locally, perched atop some slime layers. As
much as 24 feet of saturated thickness has been observed (well 003). Drilling conducted in the Cell
area in 1987 did not encounter saturated tailings Since August 1987, declining water levels
3.5
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have been observed in each of the tailing wells; this trend appears to be continuing. Figure 3.1-5 is a
hydrograph of 001 whaJ illustrates this trend. Table 3.1-4 summarizes this decline for each of the
wells in the tailings. This trend is probably a result of reduced infiltration to the tailings from the
surface and may be associated with the discontinuation of dust suppression efforts by water flooding
the tailings surface.
Water levels in November 1987 indicated a fairly uniform ground water gradient in a general westerk
direction (CDM, 1988). Figure 3.1-6 provides a water level contour map based on June 1990
measurements from the tailings monitoring wells. These recent data indicate a much different flo
path within the tailings, by the presence of a steep gradient to the west between well 003 and wells
001 and SRX-1O. A discontinuity or barrier within the tailings deposit, such as a buried access road
or sedimentation control dike is believed to be responsible for this phenomenon. In the northwest
part of the tailings the gradient becomes flatter and turns to a northerly direction. Near the west edge
of the tailings, the gradient is to the east and northeast The contours imply that a point of discharge
exists near or north of well MW-754 and could be associated with the absence of subtailings materials
in the area of the original Jordan River channel. This area has been the target of detailed studies to
characterize the hydrologic relationships at this interface.
Figures 3.1-7 and 3.1-8 are comparative hydrographs for wells MW-2OIIMW-204 and MW-301 1 M\ -
303, respectively These nested well pairs are completed in the upper and lower portions of the
saturated tailings. The hydrographs indicate that a downward gradient exists within the tailings at
both locations, suggesting that leakage through the subtailings material takes place.
3.1.2.3 UDDer Sand and Gravel Aquifer
The Upper Sand and Gravel Aquifer occurs in the upper portion of alluvial valley fill deposits whi
underlie the lake sediments and tailings/subtailings material. These deposits are interpreted to be
alluvial fan materials deposited b streams entering the Salt Lake Valley from the adjacent mountains
prior to the rise in level of the ancestral Great Salt Lake. These deposits are present throughout the
study area and generally correspond to the basin-wide, regional upper Shallow Unconfiaed Aq*afer as
described in Section 3.1.1. More recent alluvial fan materials and deltaic materials deposited ;L ’
the ancestral Great Salt Lake may also be included in this unIt in some locations near the perimere
3-6
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the study area. Recent Jordan River Valley alluviai sands and gravels may also be present and are
included in this unit.
The Upper Sand and Gravel Aquifer at the site ranges in thickness from 118 feet (MW-651) up to 158
feet (MW-401 — see Plate 3.1-3). The aquifer is mantled by floodplain deposits and/or remnants of
lake sediments over much of the Jordan Valley, but is exposed at several locations along the river
channel. The base of the unit is marked by a confining layer of clay and silt which represents a
significant hydrologic control at the site.
The Upper Sand and Gravel Aquifer consists of a heterogeneous mixture of fine to very coarse-sand
and gravel with cobbles in some intervals. Grain size analyses (Table 3.1-5) of samples obtained
from this unit show gravel content ranges up to 64 percent More gravel may be present in some
intervals, but sampling retrieval efforts were frequently unsuccessful in the more gravelly zones
Many intervals contain a significant silt/clay fraction, which in some cases appears to be of
depositional origin and, in others, related to the in-place weathering of the gravels. The grain size
analyses also show that the percentage of fines ranges between 3 and 34 percent. In addition,
interbeds of clay, silt, fine sand, and silty sand occur within the unit. These layers usually contain
more than 85 percent fines. Figure 3 1-9 shows the geotechnical test results plotted with depth to
illustrate the variability of material encountered at MW-40l. These interbeds are probably lenticular
and discontinuous since they do not appear to significantly influence hydrologic conditions at the site
They may, however, be an important factor concerning the movement of ground water on a localized
basis. The clay interbeds are interpreted to represent gaps in the deposition of high energy sediments
resulungeither from natural areal migration of stream channels or changes in the depositional
environment, such as intervals between the episodic periods of mountain building at the margins of
the valley.
Twenty-one of the ground water monitoring wells at the Sharon Steel/Midvale Tailing Site are
completed in the Upper Sand and Gravel Aquifer Most wells monitor the upper 20± feet of the
unit. Three wells (OW-3, MW-202, and MW-752) are installed deeper into the unit and are nested
with shallower completions. Figures 3 1-10, 3 1-11, 3.1-12, and 3.1-13 are potentiometric contour
maps developed from water levels measured in the upper portion of the aquifer in April, May, June.
and July 1990, respectively. During the period April through June, 1990, the maps indicate a west to
3-7
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west-northwesterly flow direction. Contours based on the July 1990 measurements show a more
northerly flow except near the eastern portion of the tailings area where flow is to the northeast
Water level measurements on a variable subset of available wells are available extending back to
October 1987. The gradient on the average planar surface describing the configuration of the
poteiniornetric surface can be determined using statistical methods to remove subjective interpretation
This best fit planar slope can be utilized in conjunction with hydraulic conductivity information to
estimate ground water flow rates and velocities. The statistical method selected consisted of a least
squares fit of the observed potentiometric surface elevations to the following equation:
= a + bx + cy
Z 1 d = Zo .
z , minimized using least squares method
where
- Least squares predicted potentiometric surface elevation
z, - Least squares difference between predicted and observed potentiometic surface ele uon
z . - Observed potentiometric surface elevation
a,b,c - Coefficients of pla. equation
x - Local northing coordinate of observation point
y Local easting coordinate of observation point
The statistical plane fits were conducted on available data with the results summarized in Figure 3 1-
-14 for available periods where flow was toward the Jordan River. An average gradient of 0.0024
feet/foot was calculated for all periods in the record except the July 1990 set, since use of a simple
plane to describe flow direction for this set is inappropriate. This average gradient may be somewhat
high, since it does not consider the reversal in flow occurring at the peak of summer pumping. A
weighted average of 10 months at the 0.0024 feet/foot and 2 months at 0.001 feet/foot was used to
develop the average year-round gradient of 0.0022 feet/foot.
Table 3.1-6 compares water levels measured in April, June and July 1990. In each of the wells
installed in the Upper Sand and Gravel Aquifer, a decline in the potentiometric surface is exhibited
The greatest decline occurred in MW-402 (6.64 feet), with declines of greater than 2 feet at A-01, A
— n
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on these materials. Blebs (blisters or air bubbles) of carbonaceous and limy mottling (spotting and
streaking) are commonly observed and could indicate some soil development at this horizon. The
material ranges from moderately stiff to hard and contains beds and concretions cemented with
calcium carbonate. Evidence of soft sediment erosion and deposition in the form of angular clasts of
sediment embedded in the matrix was also observed locally.
Water level data collected at the Sharon Steel site indicates that the confining unit maintains a
significant head differential between the over- and underlying sand and gravel formations. This unit
appears to correlate with the regional confining layer identified in the USGS studies (Waddell,
198Th)
Based on the results of low permeability column testing (see Section 3 5.2) of similar material from
the Upper Sand and Gravel Aquifer, the hydraulic conductivity of the confining unit is estimated to be
less than 2.3 x 1O ftiday.
3.1.2.5 Deeo Principal Aquifer
The Deep Principal Aquifer is also comprised of alluvial fan material similar to that which forms the
Upper Sand and Gravel Aquifer, but is separated from it by the clayey confining unit described in the
previous section. Only the upper 15-20 feet of the Deep Principal Aquifer has been explored at the
Sharon Steel/Midvale Tailings Site. Available regional data indicate that the unit ranges from
approximately 100 to 400 feet in thickness (Waddell 1987b) The base of the unit is formed by
claystones and mudstones reported to be of Tertiary age (Dames and Moore, 1988).
Locally at the sire, the Deep Principal Aquifer consists of sand, gravel, and clayey sand and gravel
Although no grain size analyses were performed on these rnaterials,resulrs would be expected to be
much the same as for the Upper Sand and Gravel Aquifer. Water well logs from nearby areas
indicate clayey interbeds are also common within the unit. Such layers may also constitute additional
confining layers to underlying sands and gravels.
Three ground water monitoring wells (MW-401, MW- 51 and MW-701) are completed in the Deep
Principal Aquifer at the S iaron Steel!Midvale Tailings Site. Wells MW-651 and MW-701 flow 20-5
, gpm at the ground surface under natural artesian pressure. While drilling MW-401, a 2-3 feet rise n
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03, MW-.451, MW-601, MW-2, and MW-13. The smallest declines were observed in wells closest to
the Jordan River. These water level changes are the result of increased pumping at large capacity
municipal supply wells located east and/or southeast of the site in Midvale and Sandy City These
municipal wells are known to have production zones that cross the regional confining zone, producing
a portion of their discharge from the Upper Sand and Gravel Aquifer.
A comparison of water levels between nested wells MW-203 and MW-202 (Figure 3.1-15), as well as
MW-751 and MW-752 (Figure 3.1-16), indicates that a slight downward gradient exists within the
Upper Sand and Gravel Aquifer. An upward gradient exists between OW-3 and OW-2 (Figure
3.1-17) adjacent to the Jordan River. Upward leakage is known to take place based on the onsite
upward head difference between the Deep Principal Aquifer and the Upper Sand and Gravel Aquifer
Since the Jordan River acts as the regional discharge point, an upward gradient would also be
expected to exist at well nests MW-203/202 and MW-75 1/752. However, localized recharge from
rainfall and snowmelt and seepage from the Perched Terrace Aquifer and Saturated Tailings Zone
may account for the observed very slight downward gradient. Pumpage from large municipal supply
wells could also be a factor in creating this gradient, since most of these wells pump only from the
basal portion of the Upper Sand and Gravel Aquifer and the Deep Principal Aquifer.
3.1.2.4 Confining Unit
The base of the Upper Sand and Gravel Aquifer is marked by a zone of fine-grained sediment. At
the site, this zone was observed to range in thickness from 6.5 feet at MW-401 to 24.1 feet at ? 4\ -
651. Drillers logs from water wells in the site study area show the presence of similar material,
which appears to correlate to this unit. Plate 3.1-4 shows interpreted extent and thickness of these
materials. The unit may be comprised of several coalescing layers or from a single quiescent episodic
deposition of flne-grained material Whichever, the unit influences ground water movement by
creating a local aquitard, or confining unit, between the Upper Sand and Gravel Aquifer and the Deep
Principal Aquifer. This confining unit appears to roughly correspond to the regionally extensive
confining unit (see Section 3.1.1) although, locally, it is thinner than expected based on the regional
information.
As observed in the exploratory borings at the Sharon Steel site, the confining unit consists of clay,
silt, and si lty/clayey sand and gravel. Table 3.1-7 presents the results of g technical tests performe
3-9
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Although these studies did not differentiate ground water usage by aquifer, they indicated that the
Shallow Tinconflned Aquifer is seldom used for water supply because of poor water quality and small
yields to wells. In contradiction, within the local Sharon Steel/Tailings Site study area, the Upper
Sand and Gravel Aquifer is utilized to a significant extent due to the aquifer’s high permeability and
good water quality. A number of municipalities, including Midvale and Sandy City, have wells that
produce from both zones, the Upper Sand and Gravel and Deep Principal Aquifers. Regionally, the
most productive wells are reported to be located in the unconfined part of the Deep Principal Aquifer
near the mountains, where the aquifer is comprised of thick, coarse-grained deposits.
To characterize local ground water use in the Sharon Steel/Midvale Tailings Site study area, records
from the Utah Division of Water Rights were reviewed in an area extending three miles north
(generally down gradient) and two miles east, south, and west of the site (UDWR, 1990a). A listing
of underground water rights is included in Appendix G. A total of 625 ground water appropriations
have been listed for this area. Of these, 587 are for wells and 38 for underground drains, springs,
and surnps. Some wells are suspected of having multiple water right numbers and multiple listings
under different, inaccurate, or preliminary locations Additional wells may also exist which are not
included in the State records Some wells represent appropriated water which has not yet been
developed by the water right holder Other wells listed may now be out of service or abandoned. No
inventory has been made to identify these situations in the field in the Midvale vicinity.
These records do not identify the aquifer from which the wells produce ground water. However.
boring logs available for some of the wells usually denote the perforated intervals. Upon review
many of the shallower wells and some of the deep supply wells produce ground water, at least in
part, from intervals correlating to the Upper Sand and Gravel Aquifer. USGS modeling estimates that
annually 89 percent of the ground water production is from the Deep Principal Aquifer. During
summer months, when production is increased due to irrigation and domestic demands, approximatel
84 percent is produced from the Deep Principal Aquifer. Many of the municipal wells are operated
only during the summer months to supply the increased demands upon the municipal systems
(Goodyear, 1990).
Table 3.1-9 provides a summary of the State records by location and well use. The largest number or
wells are located in Sections 18. 19. and 30 of Township 2 South, Range 1 East (the southwest part
of Murray City). Mosrof these wells are relatively shallow (less than 150 feet deep), small-capa it
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the water level was also observed in the borehole when this unit was penetrated indicating a strong
upward gradient occurs across the confining unit. Figures 3.1-18, 3.1-19, and 3.1-20 are
potentiometric surface contour maps based on water levels collected from these monitoring wells in
April, May, and June 1990, respectively. Each map shows a gradient to the northeast at about 0 004
feet per foot. Figure 3.1-21 provides a comparable map presenting water levels measured in July
1990. This figure shows the gradient to be in a more easterly direction and steeper at 0.014 feet per
foot.
The ground water in the Deep Principal Aquifer occurs under generally confined conditions. The
hydrographs in Figures 3.3-22, 3.1-23, and 3.1-24 indicate the presence of an upward gradient from
the Deep Principal Aquifer to the Upper Sand and Gravel Aquifer in all of the nested well pairs
except at MW-401/MW-402 in July 1990. At this location, the potentiometric level in well MW-401
has declined 13.31 feet between April 29 and July 7, 1990 with 10.27 feet of the decline occurring
since June 12. The water level in MW -402, completed in the Upper Sand and Gravel Aquifer, has
also declined 6.19 feet between April 29 and July 7 with 4.88 feet of the decline occuring since June
11 The July data show that a downward gradient existed between MW-402 and MW-401 at that
time This gradient reversal is probably a result of increased pumping by high capacity public water
supply wells located east and southeast of the site.
3.1.3 GROUND WATER USE
Detailed U.S. Geological Survey (USGS) studies have been performed to estimate ground water use
in the Salt Lake Valley, notably those by Hely (1971) and Waddell (198Th). Figure 3.1-25 displays
these estimates by type of usage on a yearly basis between 1969-1982. Ground water production by
wells has ranged from approximately 105,000 acre-feet in 1970 to 130,000 acre-feet in 1980. Hely
and Waddell’s estimates show the largest increase in usage to be for public supply and institutional
purposes. Field inspection in 1983 by Waddell indicated that 15 percent fewer wells were in use in
1983 than in 1968. Changing land use patterns manifested by the replacement of individual
household wells used for domestic and other purposes by public waxer supplies was cited as the cause
for this reduction (Waddell, 198Th) Table 3.1-8 summarizes the average annual ground water usage
of the Salt Lake Valley from 1964-1968 and 1969-1982. This table shows that an average 117,000
acre-ft/year of ground water were produced from the Salt Lake Valley between 1969 and 1982.
Production for this period wLcapproximately 9 percent higher than for the period 1964 through 1968
3-Il
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The three wells completed in the deep portion of the Upper Sand and Gravel Aquifer beneath the
tailings site have arsenic concentration values (Figure 3 3-7c) which are very low and are generally
below the detection limit of the instruments used to measure them (see Section 2.9.2.1). It is
apparent from these values that the arsenic release has not reached this zone or that the arsenic
concentrations have beer diluted to values below the detection limit.
Wells completed in the Upper Sand arid Gravel Aquifer upgradient of the tailings pile indicate little to
no arsenic concentrations (Figure 3 3-7d).
Water from wells completed in the Perched Terrace Aquifer have arsenic concentrations ranging from
4.2 g/l to 31.6 zg!i (Figure 3 3- 7 e) The latter value is from OW-i which is located on the Sharon
Steel/Midvale Tailings Site and could possibly have been influenced by the distribution of tailings on
the property.
Water from private wells and wells completed in the Deep Principal Aquifer show little to no arsenic
concentrations (Figure 3.3-7f)
3.3.2.2 Total Dissolved Solids
Values for total dissolved solids (TDS) for all samples obtained during 1990 from ground water
monitoring wells are found in Figures 3 3-Sa through 3.3-Sf. In general, the tailings waters (Figure
3 3-8a) have the highest TDS values and the waters from the private wells and the Deep Principal
Aquifer (Figure 3.3-Sf) have the lowest TDS values. Waters from wells completed in the Upper Sans.
and Gravel Aquifer just beneath the tailings pile (Figure 3.3-8b) have TDS values that are slightly
higher than both the wells completed in deeper zones beneath the tailings (Figure 3.3-Sc) and wells
upgradient from the tailings (Figure 3.3-Sd). The Perched Terrace Aquifer wells have similar TDS
values (Figure 3.3-Se) to the other upgradient wells with the exception of MW-i, which has an
exceptionally high TDS value.
3.3.2.3 Trilinear Diagrams
Trilinear diagrams permit the cation and anion compositions of many samples to be represented on a
singlegraph by which major groupings or trends in the data can be discerned visually The SDS d at 4
3-24
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Concentrations of arsenic for waters sampled in the different aquifers is of interest in this study.
Arsenic concentrations and concentrations of total dissolved solids (TDS) are discussed in the Sections
3.3.2.1 and 3.3.2.2, respectively.
Graphical and statistical valuations have been employed to interpret the standard chemical analyses.
The graphical methods were used to group the waters by plotting the major ions on thlinear diagrams.
(Section 3.3.2.3) and plotting iron and arsenic species on Eh vs. pH diagrams (Section 3.3.2.6).
Statistical methods were also used to group the waters by employing cluster and factor analyses
(Section 3.3.2.4). The results of isotope analyses of the ground waters are discussed in Section
3.3.2.5.
3.3.2.1 Arsenic Concentrations in Ground Waters
Arsenic concentrations are summarized in Table 3.3-1 and in Figures 3.3-7a through 3.3-7f. These
tables and figures list all samples collected from monitoring wells (filtered through 0.45 micron
filters) and the associated arsenic values measured by the CLP laboratory in 1990. Arithmetic means
are presented in Table 3.3-1 for wells with multiple arsenic values and for each aquifer. Means were
calculated on a conservative basis with values in the data set below detection set to the detection limit
for the computations. The aquifer means are calculated using the well means. Arithmetic means are
used here for strictly qualitative comparison purposes, since the sample populations rarely follow a
normal distribution.
The wells completed in the Saturated Tailings Zone have the highest values for arsenic concentrations.
with an average value of 920 ig1 (Figure 3.3-7a).
The wells completed in the shallow portion of the Upper Sand and Gravel Aquifer beneath the tailings
(also described using the term, subtailings) have arsenic concentrations that range from less than 1.0
ig/l to 288 g/1, with an average value of 68 Mg /i (Figure 3.3-7b). The arsenic concentrations are
highest at MW-601 and A-03 which are in close proximity to one another. If only one value of
arsenic concentrations for both wells is used then the average value for the shallow wells is 49 ig/l
These values are significantly higher than any of the upgradient wells, indicating release to the aquifer
from the tailings.
3-23
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normalized (see Table 3.3-3). A cluster analysis was performed on this subset and is presented in
Figure 3.3-lOa. Another cluster analysis was performed on a second subset of the SDS data
containing log normalized values of all major metals with data consistently above the detection limit
Table 3.3-2 lists the metals data used before they were log normalized. The results of the metals data
cluster analysis are presented in Figure 3.3-lOb.
The dendrograins from both cluster analyses places the chemical analyses of samples obtained from
Saturated Tailings wells (Group I) and the Upper Sand and Gravel Aquifer below the tailings
(shallow completion- Group 2) wells in closer relationship to each other than chemical analyses from
other wells. This suggests a chemical relationship between waters in the tailings and waters in the
Upper Sand and Gravel Aquifer just below the tailings, with a possibility that the water in the Upper
Sand and Gravel just below the tailings may be a result of mixing between the tailings water and
water from the Upper Sand and Gravel Aquifer upgradient of the tailings area.
Factor analysis is a mathematical method which reduces multivariables of a problem to a manageable
size In this study, factor analysis was used to consolidate the relationships of the log normalized
SDS major ion data (Table 3.3-4) Into four factors (Table 3.3-5), with similar data having similar
factor values. All major ions were chosen because they were thought to have the greatest variabilit
between samples. A plot of the values from the first factor (Figure 3.3-11) indicates a close
relationship among the wells in Group 1 and Group 2
3.3.2.5 Stable Isotoi,es and Tritium
Elemental isotopes in the environment (Table 3.3-6) may act as indicators of the source and history ot
the material being studied. The isotopes of oxygen and hydrogen are used in ground water studies as
indicators of the source of the water. Sulfur isotopes are used as indicators of either a mineralogical
or biological source of the sulfur in the water. In general, isotopic fractionation occurs during severai
different kinds of chemical reactions and physical processes:
• Isotopic exchange reactions involving the redisuibution of isotopes of an element among
different molecules containing that element.
• Unidirectional chemical reactions in which reaction rates depend on isotopic compositions of
the reactants and products. Examples of unidirectional reactions are precipitation and
dissolution of minerals and biological reduction of elements.
.,
3-26
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from this study are plotted in Figures 3.3-9a through 3.3-9f. The TDS values shown on the figure
are calculated TDS values vs. the actual measured values. Figure 3.3-9a has plotted, in addition to
the compositions of the Saturated Tailings waters, the outlines of the groupings from the other
diagrams.
The results from the triinear diagrams indicate that there are three groups of waters at the Sharon
Steel/Midvale Tailings Site;
• Group I - Saturated Tailings. The ground water in the mill tailings aquifer are classified as
CaSO 4 type waters.
• Group 2 - Upper Sand and Gravel Aquifer beneath tailings (shallow completions). This
water is classified as a calcium-sodium sulfate water.
• Group 3 - Upper Sand and Gravel Aquifer beneath tailings (deep completions), Perched
Terrace Aquifer and Upper Sand and Gravel Aquifer upgradient of site (background). This
water is classified as a calcium-sodium chloride-sulfate water, but generally does not have a
dominant anion or cation.
The water sampled from the Deep Principal Aquifer is scattered on the diagram and does not group
together, but generally fails in the same area as the non-tailings waters (Figure 3.3-9a).
It appears from the diagrams that the water from Group 2 has a major anion-canon composition
intermediate to the Group 1 and the Group 3 waters.
3.3.2.4 Statistical Evaluations
Two statistical evaluations were performed on the ground water data: cluster and factor analyses
The geologic applications and mathematical basis of these techniques are described in Davis (1973)
In essence, cluster analysis places objects (in this case the water sample analyses) into more or less
homogeneous groups such that the relation between the groups is revealed. The result of cluster
analysis using the SDS data from this study are shown on two dendrograzns (Figure 3.3-lOa and 3 3-
lOb).
The cluster analysis was performed on two subsets of the SDS data. The first subset contained all
parameters except those that were consistently below the detection limits. The data set was then log
C
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• The extremely low vertical hydraulic conductivity of the aquitard separating the Deep
Principal and Upper Sand and Gravel Aquifers limits movement of water, even under
gradient reversal conditions
• Aquifer testing at the Site in’dicates that the Upper Sand and Gravel Aquifec responds as a
non-leaky system and does not show recharge boundary effects from the Jordan River for
durations of pumping of a least a week. Hydraulic characteristics of the Upper Sand and
Gravel Aquifer at the site indicate that the aquifer has a hydraulic conductivity of 135 to
208 ft/day and responds as an aquifer which is transitional between semi-confined and
unconfined.
• The Saturated Tailings Zone overlies low permeability clays or slimes, except where it
overlies the buried channel of the Jordan River The tailings are currently draining and
are anticipated to stabilize at a level that will allow discharge of all water percolating from
the surface to the Upper Sand and Gravel Aquifer. Steady state discharge from the
tailings to the Upper Aquifer is estimated to be 0.08 feet/year with the current surface
management practices
4.2 GEOCREMISTRY
• The migration of contaminants from the tailings into the subtailing soils and aquifer
- materials is shown by chemical analyses of solid materials and water from below the
tailings. Contaminants (including arsenic, lead, and zinc) have migrated from the tailings
into the material below the tailings
- This contaminant migration is shown by analyses of sohd samples in 0031A03,
MW-2011202, MW-301/302, MW-751 and MW-601. Samples from these borings
showed elevated concentrations of the contaminants in samples immediately below the
tailings with concentrations decreasing with depth below the tailings. At MW-
2011202, the contamination is contained in a mixed zone of native materials and
tailings. At MW-601, MW-301/302, and 003 1A03 the subtailings material is a low
permeablélayer including an organic-rich, reducing zone at the top of the layer hi
‘a
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4.0 SUMMARY OF RESULTS
This section provides a summary of results of studies described in earlier sections.
4.1 HYDROGEOLOGY
I Four zones of hydrologic significance are present at the Site in the subsurface:
- the Deep Principal Aquifer
- the Upper Sand and Grave! Aquifer
• the Perched Terrace Aquifer
- the Saturated Tailings Zone
• An areally extensive aquitard separates the Deep Principal Aquifer and the Upper Sand
anci Gravel Aquifer
• Ground water in the Deep Principal Aquifer flows toward pumping centers to the northe . -
of the site
• The Upper Sand and Gravel Aquifer is used for drinking water supply an the area east arid
southeast of the site, production from this aquifer reaches a peak during peak summer
pumping periods. Throughout most of the year, ground water in the Upper Sand and
Gravel Aquifer beneath the site flows west to northwest and discharges into the Jordan
River; during the peak summer pumping season, the flow changes to a more nor .:lv anJ
easterly direction
• An upward gradient exists from the Deep Principal Aquifer to the Upper Sand and Gravel
Aquifer at most locations and times of the year near the Site. An exception to this was
observed at the MW-401/MW-402 site, where a significant downward gradient developed
due to peak summer pumping from surrounding municipal supply wells. Future increase
in pumping may lead to a more widespread gradient reversal.
4-1
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upgradient wells. This result suggests that the water below the tailings in the Upper
Sand and Gravel Aquifer resulted from mixin , of tailings and upgradient water.
- Factor analyses using a combination of the concentrations of all major anions and
cations result in distinctly different factor scores for water from wells completed
upgradient of the site in the Upper Sand and Gravel Aquifer and for water from wells
completed in the Saturated Tailings Zone. Waters from the shallow portion of the
Upper Sand and Gravel Aquifer below the tailings have factor scores between the
upgradient and tailings waters. This evaluation supports that waters in the shallow
portion of the Upper Sand and Gravel Aquifer wells result from mixing of tailings and
upgradient type waters
- Cluster analyses using metal concentrations and all parameters with detectable
concentrations indicate that waters from the tailings wells and waters from the
upgradient Upper Sand and Gravel Aquifer cluster into distinct groups. Waters from
the upper portion of the Upper Sand and Gravel Aquifer below the tailings also cluster
together in a group between the upgradient and tailings groups. Waters from the
lower poruon of the Upper Sand and Gravel Aquifer below the tailings group cluster
with the upgradient waters from the Upper Sand and Gravel Aquifer.
• Evaluation of the results from analyses of hydrogen and oxygen isotopes (3D and
ö”O) indicate that waters from the tailings and waters from the Upper Sand and
Gravel Aquifer upgradient from the Site are distinctly different. Waters from the
upper portions of the Upper Sand and Gravel Aquifer below the tailings have 3D and
ô O between the tailings and upgradient waters.
• Analyses of arsenic(TrI) by differential pulse polarography indicates that the majority of the
arsenic (90 to 100 percent) in the water from the tailings wells is arsenic(III). The
majority of arsenic (67 to 79 percent) in well MW-601 completed in the upper portion of
the Upper Sand and Gravel Aquifer below the tailings is arsenic(V). Most waters from
the shallow portion of the Upper Sand and Gravel Aquifer have a higher percentage of
arsenic (V) than the tailings wells. The measured values are not consistent with
4-4
-------
this reduced zone, sulfides h 1 ve precipitated. At MW-201/202 and MW-751, the lo
permeable zone is not present and contaminants migrate directly into the Upper Sand
and Gravel Aquifer.
• Contaminants (including TDS, arsenic, and zinc) have migrated from the water in the
tailings through the subtailmgs material or directly into the water contained in the Upper
Sand and Gravel Aquifer.
- Elevated concentrations of these prameters are observed in selected wells completed
in the upper portion of the Upper Sand and Gravel Aquifer below the tailings. These
wells include OW-2, AOl, A03. MW-601, A02, MW-302, MW-203, MW-751, arid
MW-753. Concentrations of arsenic ranged from
-------
thermodynamic calculations, indicating an incomplete thermodynamic data base, high
measured E1 i values or nonequilthriurn conditions. However, the concentrations of iron(11)
and iron(I11) generally agree with thermodynarrnc predictions.
I Batch test results using contaminated water from the tailings (arsenic concentrations =
1,035 gfL) and non-contaminated soil indicates that the arsenic adsorption properties are
quite variable for the different materials at the site.
4.3 MODELING
• The results of the solute transport modeling effort demonstrate that concentrations of
arsenic in the shallow portion of the Upper Sand and Gravel Aquifer beneath the tailings
and downgradient of the tailings have already or will reach the MCL in the future.
• Scenarios for hypothetical receptor wells located on-site indicate that the arsenic MCL has
already been reached. This agrees with the arsenic concentrations found in waters from
wells completed in the shallow subtailings portion of the Upper Sand and Gravel Aquifer
• Scenarios for hypothetical receptors under conditions of a northerly hydraulic gradient
indicate that
• Arsenic concentrations for waters in a receptor well at the northern edge of the Site
will reach the MCL before the year 2000.
- For a receptor 1,000 feet north of the Site, the arsenic MCL will be reached in
approximately 10 years after the onset of the northerly hydraulic gradient.
• A receptor well located in-line with the Oak St. well will have concentrations of arsenic at
or above the MCL in approximately 425 years after the time that the hydraulic gradient
reverses and the Jordan becomes a losing river.
4-5
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Sharon SteellMidvale Tailings Site Mining Waste NPL Site Summary Report
Reference 10
Excerpts From Feasibility Study Operable Unit 1, Mill and Tailings Site,
Sharon SteellMidvale Tailings Site, Midvale, Utah, Volumes I and II;
Prepared for EPA by Camp, Dresser & McKee;
October 1990
-------
REMEDIAL PLANNING ACTIVITIES AT
SELECTED UNCONTROLLED HAZARDOUS
SUBSTANCES DISPOSAL SITES IN A ZONE
FOR EPA REGIONS VI, VII, & VIII
U.S. EPA CONTRACT NO. 68—W9-0021
DRAFT FINAL
VOLUME I
FEASIBILITY STUDY INTRODUCTION
SHARON STEEL/MIDVALE TAILINGS SITE
MIDVALE, UTAH
tjork Assignment No.: 003-8L40
Document Control No.: 7760-003—FS—BLRI(
Prepared for:
U.S. Environmental Protection Agency
Prepared by:
CD II Federal Programs Corporation
8215 Melrose, Suite 110
Lenexa, KS 66214
This document has recei ;ed internal technical review by EPA, CDM/FPC. and the
Sharon 5tee1/Midv e Technical Advisory Committee. Their comments and
revisions are incorporated in this copy. This document is therefore terned
Draft Final, and viii be finalized following public review and comment.
I
-------
o Direct ingestion of tailings or contaminated surface soils
o Dermal absorption of tailings or contaminated surface soils
o Ingestion of contaminated ground water
o with contaminated surface water and sediments
o Inhalation of dust
o Ingestion of produce grown in contaminated soils or irrigated with
contaminated ground water
The following sections describe these pathways of exposure.
Direct Contact
Direct contact with tailings and soil is probably the most common exposure
route for the chemicals at the Sharon Steel/Midvale Tailings site. Direct
contact through ingestion may result from the actual consumption of
tailings and soil or through mouthing of soiled objects or extremities.
Derma]. absorption is also a direct contact pathway; but is limited to
instances when exposed cuts or scrapes allow absorption through the skin.
Absorption of the contaminants of concern through unbroken skin is not
considered significant.
Ground Water
Ground water also provides a pathway for the transportation of contaminants
leached from the soil or tailings. Receptors using the ground water as a
drinking vater supply or for crop irrigation would then be exposed to risk.
Surface Water and Sediments
The surface water system represents a potential route of exposure. Both
the Jordan River and a 22-acre wetland on the Sharon Steel property are
subject to metal releases from airborne tailings and soil, as well as the
shallow unconfined aquifer. Dissolved and suspended metals would,
3—3
-------
REMEDIAL PLANNING ACTIVITIES AT
SELECTED UNCONTROLLED HAZARDOUS
SUBSTANCES DISPOSAL SITES IN A ZONE
FOR EPA REGIONS VI, VII, & VIII
U.S. EPA CONTRACT NO. 68-V9—0021
DRAF! FINAL
VOLUME II
FEASIBILITY STUDY - OPERABLE UNIT 1
MILL AND TAILINGS SITE
SHARON STEEL/MIDVALE TAILINGS SITE
MIDVALE, UTAH
Work Assignment No.: 003-8L40
Document Control No.: 7760-003-FS—BLRK
Prepared for:
U.S. Environmental Protection Agency
Prepared by:
CDM Federal Programs Corporation
8215 Meirose. Suite 110
Lenexa. KS 6621’4
Th1 5 document has received internal technical review by EPA, CDM/FPC. and
The Sharon Stee1/Mi vale Technical Advisory Committee. Their comments and
revisions are incorporated in thiS COpy. This document is therefore termed
Draft ririal, and il1 be finalized following public review and comment.
-------
I waI Soil ( itami,jated Siti fare Sull Tail tr€s
Sit (ace Sut ii e Sul a fae
let tace Flo tpIain let i ace Fkxslplain R suk it lal Hi I I Site (Oxidizaj) (I es) (tb x1dIzed)
- -(IrE/ g)---- -— ____ _______
Alt.nm in 11,669.0 1,281.0 12,461 .0 I0 , U11.0 9,560.0 9,267.0 3,982.0 3,210.0 3,002.0
Aiit nutty 6.1 <5.5 6.4 8.8 5.1 72./ 71.5 16.0 17.0
Atsenic 15.2 5.7 31.5 40./ 65.5 158.0 425.1 320.2 411.2
Cadniiun 3.2 2.0 5.4 7. 1 12.5 27.6 46.8 37.1 36.4
(liuiiiit.n 18.0 11.9 17.8 18.6 15.8 29.8 25.4 17.0 18.3
Copper 81.4 40.7 160.6 144.6 195.1 324.1 298.5 760.2 578.1
97.0 78.6 373.2 536.8 722.0 2,100.0 6,278.0 5,470.0 5,2 .0
t Iangane e 454.3 249.5 466.0 452.8 5 1 ) 0.9 833.7 1,199.1) 1,497.0 2,032.0
SIlver 1.4 <1.6 1.9 2.8 3.0 10.4 26.9 26.9 27.1
l ltal liuii B i t Nt 1.6 1.4 2.0 3.3 3.2 8.0
7,ju,c 124.3 100.1 320.8 5 )/.4 591.8 2,143.0 4,821.0 6,048.0 6372.0
no 4 5 23 17 22 Il 13 22 4
Sediment
Jordan
Surface
River
Vater
Gioiu l ValetS
Air t ta Fran
(h ceder 1987 Event
I ilu l I nvlu 1
(n /Eg)
Perdied In Upper Sand &
Tai1li s Gravel/Sha1Io
t ?ef) Pt Inc.
Residential
uifet/
lelLs
Upstream
Ikwnstream
Elanent
Upstream
(n / l g)
Iliwnstteam
-(t /L)
—
Ahiiiiinin
1492.0
3365.0
1010.0
1030.0
21.0 25.84
26.15
-
-
Aittititiny
<29.1)
<34.0
<60.0
<60.0
<28.1) 30.18
29.59
-
-
Arsenic
1.5
16.1
16.0
10.0
1.63 28.14
1.64
314.1)
438.0
Cadmitun
<1.5
2.2
.36
.44
3. 1) 3.1)
3.0
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APPENDIX A
BASELINE RISK ASSESSPqEN’r
FOR GROUND WATER
SHARON STEEI./N1DVALE TAILINCS SITE
NIDVALE, UTAH
OCTOBER 1990
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5.2 FUTURE MODELED WATER QUALITY SCENARIOS
Table 5-3 summarizeS carcinogenic risks from arsenic in ground water for
the future on-site and downgradient domestic veil scenarios at years 2020
and 2090. The on-site veil scenario and dovngradient domestic well (3)
have risks ranging from 4x10 3 to 9x10 3 associated with them for the years
2020 and 2090 respectively. These risks exceed EPA’s allowable risk range
of lO6 to The dovngradient domestic veil (5), however, has a risk
of approximately 1x10 4 for the years 2020 and 2090 which fails vi thin
EPA’s allowable risk range.
Table 5—4 summarizes the CDI:RfD ratios for arsenic for future scenarios.
The ratio ranges from 2.3 - 5.0 for the on—site domestic veil and the
dovngradient domestic veil (3). The ratio associated with ingestion of
ground water from downgradient domestic well (5), however, is less than
one, indicating that adverse noncarcinogenic health effects are unlikely t
occur as a result of this exposure.
5.3 UNCERTAINTIES ASSOCIATED WITH RISK CHARACTERIZATION
The uncertainties associated with the risk characterization information
presented above are limited. For noncarcinogenic effects, the CDI:RfD
ratios are within the same order of magnitude as or greater than the RfD
- safety factor of one. This indicates that there is only a small degree of
uncertainty surrounding the potential for noncarcinogenic adverse effects
from exposure to arsenic calculated according to the exposure scenario
defined in this BA. Although the arsenic MD is currently under review by
EPA, Its safety factor of one indicates that because the study was based o
a human epidemiological study on a large population, relatively little
uncertainty exists.
EPA has calculated a CPF for ingested inorganic arsenic of 1.75 based on
long term epidemioiogical data on a large population in Taiwan. There is
data which suggests, however, that at low doses, inorganic arsenic
5—4
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5.0 RISK CHARACTERIZATION
This section provides quantitative risk estimates for the ground water
ingestion pathway. Both carcinogenic and noncarcinogenic r sks from
arsenic are evaluated. Carcinogenic risks are calculated for each
scenario by multiplying the CDI by the cancer slope factor (CS?) for
arsenic as follows:
Excess lifetime cancer risk = CDI x CSF
Where
CDI Chronic daily intake (mg/kg/day)
CS? 1.75 (mg/kg/day) 1
Noncarcinogeni: risks are evaluated by the ratio of the CDI to the
reference dose (RfD) for arsenic. The RfD for arsenic, 1x10 3 mg/kg/day
(USEPA 1990b), has recently been withdrawn but will be utilized here for
purposes of comparison with the soil/tailings RA. Ratios which exceed one
indicate that adverse health effects may occur. Ratios less than one
suggest that adverse health effects are unlikely to occur.
5.1 CURRENT WATER OUALITY SCENARIOS
Table 5-1 summarizes carcinogenic risks from arsenic in ground water for
the on—site and dovngradient domestic well scenarios. Both the on—site
scenario at 4.4x10 3 and the dovngradient scenario at 1.2x10 3 exceed EPA ’s
allowable risk range of io_6 to 10 .
table 5—2 summarizes the CDI:RfD ratios for the current water quality
scenarios The hazard index for arsenic is 2.5 for the on-site well and
0.7 for the downgradjent well.
I
5-1
-------
6.0 INTEGRATION OF GROUND VATER PATHVAYS VITH OTHER PATRVAYS
The soils/tailings RA (Volume III, Appendix B) characterized risks
usocfated vith ingestion of Contaminated soils, tailings, dust, and
produce as veil as inhalation of contaminated airborne particulates under
both current and future land use scenarios. To accurately evaluate total
potential future risk, It is necessary to combine the risk from
soils/tailings pathways with the risk from the ground water pathway for the
future land use scenarios.
Future site use scenarios In the Soils/tailings PA assume future
residential use of the mi llsite. These future site use risks are most
appropriately combined .‘ith the ground water risk estimated for an on-site
domestic veil.
6.1 CURRENT SCENARIOS
Table 6—1 summarizes the risks from all pathways for the current scenarios.
The on—site residential scenario assumes residential use of the millslte
including construction of a shallow domestic well. The off—site
residential scenario assumes ground water exposure from a shallow domestic
well near the Site boundary, dovngradie of the site and soils/tailings
exposure from off—site residential areas. For the on—site residential
scenario, the CDI:RfD ratio of 7 exceeds one and the excess upperbound
lifetime cancer risk of 5 x lO exceeds EPA’s allowable risk range of io_6
to 10 . For the off-site residential scenario, the risks are less. The
CDI:RfD ratio of 3 still exceeds one, however, and the excess upper bound
lifetime cancer risk of 2 x 10 still exceeds EPA’S allowable risk range.
To pu these risk numbers in perspective, it is worth noting that the
current drinking water MCL for arsenic (0.05 mgiL), using the same intake
assumptions as this RA, results in a CDI:RfD ratio of 2 and an excess
-------
TABLE 5-3
POTENTIAL UPPERBOIJND EXCESS LIFETIME CANCER RISKS
FROM GROUND WATER FOR FUTURE MODELED WATER QUALITY SCENARIOS
Excess
scenario
CDI
(mg/kg/day)
Slope Factor 1
(mg/kg/day)
Upperbound
Lifetime
Cancer Risk
on-Site Domestic Well
Drinking Water
Year 2020
3.li x 10
1.75
5.6
10
Year 2090
5.0 x
1.75
x
8.8 x 10
Dovngradient Domestic
Well
( 3 )a
Drinking Water
Year 2020
2.3 x 1O
1.75
4.0
10
Year 2090
3.4 x 1O
1.75
x
5.6 x
Dovrigradient Domestic
Well
( 5 )b
Drinking Water
Year 2020
7.1 x 10
1.75
1.2
10
Year 2090
10
x
a Assumes that current summer pumping rates and patterns occur year round.
b Assumes increased pumping at the Oak Street Well in Midvale such that a
reversal of the current hydraulic gradient occurs.
5-5
-------
upperbound lifetime cancer risk of 1 x 10 . The present MC I.. for arsenic
(0.05 ug/L) was actually established in 1942 by the U.S. Public Health
Service to protect the public from acute health effects. At that time,
adverse health effects from chronic exposure had not been investigated and
were not understood. As an interim measure, EPA has continued to use 0.05
ugfL as the MCL. Currently, however, EPA is re—evaluating the MCI.., as well
as the recently withdrawn reference dose (RfD), based on more recent
toxicological and epidemiological data. Additional considerations regarding
the MCL may include the natural background concentrations of arsenic in many
municipal water systems and technological problems associated with removing
arsenic from these water systems.
From a remedial perspective, if remediation activities substantially reduced
or eliminated risks from the Soils/tailings pathway for the current off-site
scenario, the remaining ground water risk would be •quivalen to the risk
associated with the MCL for arsenic. In the future, however, the ground
water risk would increase due to the predicted increased concentrations of
arsenic in ground water.
6.2 FUTURE MODELED WATER QUALITY SCENARIOS
Table 6—2 summarizes the risks from all pathways for the future scenarios
based on ground water quality modeling results. The on—site residential
scenario assumes future residential use of the mill site including
construction of a shallow domestic well. The off—site residential scenario
assumes future ground water exposure from a shallow domestic well near the
site boundary, dovngradfent of the site, and soils/tailings exposure from
off-site residential areas.
For the On—site residential scenario, total risks would continue to increase
due to the predicted increased degradation in ground water quality such that
In 30 years the CDI:RfD ratio would be 7 and the excess upperbound lifetime
cancer risk Vould be 7 x 1O . In 100 years, the CDI:RfD ratio would be 9
and the excess upperbound lifetime cancer risk would be 1x10 2 .
6-3
-------
TABLE 6-1
SUMMARY OF RISK CHARACTERIZATION RESULTS FOR
SOILS/TAILINGS PATHVAYS AND GROUND WATER PATHWAY
FOR FUTURE LAND USE SCENARIOS BASED UPON CURRENT WATER QUALITY
Exposure Scenario
CDI :RfD
Ratio for
Arsenic
Excess Upperbound
Lifetime Cancer Risk
On-Site Residential
Soils/Tailings Pathways
4
. 1.0
x 1O
Ground Water Pathway
2.5
4.4
x 10
TOTAL:
6.5
5.4
x 10
Off-Site Residentiala
-4
.
Soils/Tailings Pathways
2
5.0
x 10
Ground Water Pathway
TOTAL:
0.7
2.7
1.2
x 1O
1.7
x
a This scenario assumes ground water exposure from a shallow domestic well
near the site boundary. downgradieflt of the site, and soils/tailings
exposure from off-site residential areas.
p)
6-2
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filansais ALT4A.WkI
SCILINING or ILHLDIAI. ACTION ALTtRNAT1V S Pa,i I
COST C$TJHATINO WOP I SHII? DATG. 02-Oct-IS 1 1, 12 PIt
.3l% to -30% Level) IV . 51.1
pIOJICT. INASON STCtLIHIDVALI TAILINGI SITS
PIASIIILITY STUDY - OPUASLI UNIT O Il
ALTISNATIVI 4. CAPPING
DSSCIIPTION. ConetructiOn ot a .u lti- lsyeISd soIl cop
groundwater COntrOl with •it,.ctlOfl. tgeat•Int and Jordan liver disposal.
sill Isoility desolition and d.bris d$.pos.i.
OIUCT CAPITAL COSTS
Inc1udis Labor. Iquip.snt. & HategisiS. Unless Oth.fwtsi Noted)
COST UNIT CAPITAl.
c ONPONINT UNIT QUANTITY COST COST
I. lecavatlon
a. Hill facility Aria CV 133000 $8 1i . 07 1.ll0
CaGey & Spread)
b. Wetlands pa.ovell.store CV 43 0 l Ill $438,000
0. TailingS Weal ot Jordan CV 22300 so sss*.l•I
ladY I Spread)
2. Surlaci Water Control
a. legrading 4 lncludii CV 8 4S IS SI $ 4SlSS
lb. 0U3 soils)
b. Osiana Canal S.hsb U 3950 $75
a. Slops Stabi lilat lofl Iloil C.s.nt ) If $800 $871 $5171811
3. CappIng 4Inc l .111 (scility area)
a, $2• Gravelly Send CV 40010 1 I I I $3941110
H. 34 Vegetation Layer CV 50030 . $8 $ , 8IS .S 0 l
0. p,v*git$ttOfl AC 348 18)3 5* 57.000
4. Groundwater
a. Oroundwatir SatractiOn IA 21 $I .500 $448800
b. On-site ?reat.ent LS I $585,000 $115,110
o. pu,plnglDiSCbarQi to Jordan liver 1.5 I $397,400 $391,508
d. Inleroepter Trench U 5580 $82 $344880
S M I II reclllty
a. IaoilttY D.soltIiOfl L8 I 1573.800 3514,00 1
Disposal at USPCI 1.8 I $2,215,000 53,35 5800
b. US? Sesovel 1 5 3 5)7.310 $35,000
C. AsbastlS Pipe Disposal I A 5000 $3 $31,000
4. Liquid Otuposal GAL *0000 32 116.500
CV 500 541 $34,011
11(0 005
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APPENDIX C
COSTS
ts for •ach alternative were develop.d as foUowe. Direct capital costs
Lnclud• materials, labor ii d egU.L ent costs for th. remedial, action items in
each alternative. Th. en. t COlt involve in the iflsti .tutional control of
deed, well. p.rm .t restrictions and re—zoning ordinance, is also included here.
Indirect capital costs were •stablished as percentages of direct capital costs,
and include Engineering and Design COsts, contingency allowances to cover costs
related to unforseen circumstances, other direct costs such as legal and
regulatory fees, and mobilization/demobilization costs incurred by the
construction crews.
Annul o&x costs are post—construction costs which include the costs for yearly
s .t. reviews and an •st .mate of remediation activities as a result of those
rev2ews. Ad .n .str*t ion colts related to those remedies, and adeinistering deed
and permit restrictions on the site were also included.
costs were evaluated over a 30 year p.riod (unless noted otherwise) presented as
a Present Worth Total Cost.
0
C- I
-------
Pag i S
5CRCCNlNG or REIILDIAL ACTION ALTERNATiVES
COST ESTIMATING WORKSHEET
1.51% tO -31% L.v.l)
PROJECT. SHARON STLCLIHIOVALC TAILINGS SITE
ISAIISILITY STUDY - OPERASLE UNIT ONE
ALTSRNATIVS 4. CAPPING
DIRECT ANNUALIURIODIC COSTS
COST COMPONENT UNIT
DIRECT ANNUALIPERIOD1C COSTS
s.c .,
a. Inspection CA
b. Mowing A I.w.g.tatlon CA
a. Cap Repair A Maintenance IA
2. Groun4wa l il
a. Replace Groundwater
lutraction Wells CA
b. Will CAN 5.5
0. Trialuent Plant 0 A H 5.3
4. Pu.pinglDiSCbaESS to Jordan OAH LS
TOTAL DIRECT ANNUAL COSTS.
TOTAL PRESENT WORTH Of DIRECT COSTS.
TOTAL PRESENT WORTH Of DIRECT PERIODIC COSTS.
TOTAL PRUENT WORTH 01 DIRECT APNUALIURIODIC COSTS.
ONE EVERY
YEAR
ANNUAL
ANNUAL
ANNUAL
INDIRECT ANNUALIPERIODIC COSTS P.ra.ntagi ot
Ad.ini.IfaIiOa ill) 5.5
Maintenance Reserve &
Contingency Cost. 3 %I 5.8 ANNUAL
TOTAL PRESENT WORTH or INDIRECT ANNUAL,PERIODIC COSTS.
31 $34111 1 ala
s s . 5ee SI $413111 ala
DATE. WI-Oct-90
ST. SLK
0 1.12 nI
QUANTITY
fREQUENCY 51CR YEAR)
ANNUAL
ANNUAL
ANISUAL
PRESENT WORTH
DIRECT LIPS 01
ANNUAL ITCH ANNUAL PIRIODIC
COST SYCARSI COSTS COSTS
UNIT
COST
$2 . . ’.
I $5530.
$ $ 11111
I $5455,
* $4.....
I $S3.5I•
I S.*II
30 $3) ISI
31 $541...
31 $ 113,111
13. 1 5 1
$SS.2 1 1
sissee
$ 14,50 1
$41111
$5). 551
$11.11
$243, 111
ala
ala
ala
3• $111111 ala
31 $411111 ala
31 SSIS.ISI ala
31 $544,111 ala
$34141 1 1
1 l
Total Direct Annual Costs).
ANNUAL
TOTAL PRESENT WORTH ICapital & Annua*lPeriOdiCI COSTS.
14). I)S.IIl
-------
5CP LN3MG Of RLHLDIAL ACTION ALTSRNAT IVCS
COST SSTIHATING WORNBHIST
1.1.1 to •3S% L•vsl)
ROJCCT, SHARON $TCELIHIDVALS TAILINGS SITS
UASISILITY STUDY - OPIPABIS UNIT ONC
ALTSPNATIVI 4. CAPPING
INDIRLCT CAPITAL COSTS 1% ot DIrscI Csp&tsl COStS
i. Inginisring & D.slgn US$1
3. Conttng.ncy A)lowsna. 2951
3. Othir Indlr.ot Costs
A. L•gsI (5%)
S. R.gul.to:y (5%)
C. HobIIIsstIon/DsaobIllzsUon (*0%)
TOTAL INDIPCCT CAPITAL COSTS
TOTAL CAPITAL COSTS (DIRSCT • IMDIRCCT)
$3. 154,500
$4. 1)3,000
$1 • 730.000
SI. 731.10 1
$2 , 449. e lI
5I4,8Il.SlS
539.500.000
Psg. 3
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I ) ,
Mining Waste NPL Site Summary Report
Silver Bow Creek/Butte Area Site
Butte, Montana
U.S. Environmental Protection Agency
Office of Solid Waste
June 21, 1991
FINAL DRAFT
Prepared by:
Science Applications International Corporation
Environmental and Health Sciences Group
7600-A Leesburg Pike
Falls Church, Virginia 22043
-------
DISCLAIMER AND ACKNOWLEDGEMENTS
The mention of company or product names is not to be considered an
endorsement by the U.S. Government or the U.S. Environmental
Protection Agency (EPA). This document was prepared by Science
Applications International Corporation (SAIC) in the partial fulfillment
of EPA Contract Number 68-WO-0025, Work Assignment Number
20. A previous draft of this report was reviewed by Russ Forba, Sara
Weinstock, Ron Bertram, Mike Bishop, and Scott Brown of EPA
Region Vifi [ (406) 449-5414], the Remedial Project Managers for the
site, whose comments have been incorporated into the report.
-------
Mining Waste NPL Site Summary Report
SILVER BOW CREEK/B LIE AREA SITE
BLYITh, MONTANA
INTRODUCTION
The Site Summary Report for Silver Bow Creek/Butte Area is one of a series of reports on mining
sites on the National Priorities List (NPL). The reports have been prepared to support EPA’s mining
program activities. In general, these reports summarize types of environmental damages and
associated mining waste management practices at sites on (or proposed for) the NPL as of February
11, 1991 (56 Federal Register 5598). This summary report is based on information obtained from
EPA files and reports and on a review of the summary by the EPA Region Vifi Remedial Project
Managers for the site, Russ Forba, Sara Weinstock, Ron Bertram, Mike Bishop, and Scott Brown.
SITE OVERVIEW
The Silver Bow Creek/Butte Area site is one of four separate but contiguous Superfund Sites located
along the course of the Clark Fork River in southwestern Montana. The four sites, known
collectively as the Clark Fork Superfund Sites, are the Anaconda Smelter site, the Milltown Reservoir
site, the Montana Pole site, and the Silver Bow Creek/Butte Area site (see Figure 1). All four sites
have the potential to contaminate Silver Bow Creek and/or the Clark Fork River (Reference 1, page
4). Also, Miitown Reservoir has the potential to contaminate the sole-source aquifer below
Missoula. The Superfund effort in the Clark Fork Basin encompasses the largest geographic area of
all Superfund assignments in the United States. Except for the Montana Pole site, contamination at
the sites is primarily mining wastes and heavy metal-laden soils and water. The Montana Pole site,
which lies adjacent to the Silver Bow/Butte Area site, is contaminated with wood-treating wastes
(Reference 1, pages 3 and 4).
The Silver Bow Creek/Butte Area Superfund Site is the largest and most complex of the four sites.
Silver Bow Creek has historically received discharge from mining, smelting, wood treating, and other
industrial sources for over 110 years (Reference 5, page 1).
The Silver Bow Creek/Butte Area site includes the Cities of Butte and Walkerville (population
38,000), the Berkeley Pit (a nonoperating open-pit copper mine); numerous underground mine works
(operated by New Butte Mining, Inc.); the Continental Pit (operated by Montana Resources); Silver
Bow Creek; Warm Springs Ponds (mine tailings); and Rocker Timber Framing and Treating Plant.
The approximate size of the Silver Bow Creek/Butte Area site is 450 acres.
l
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I
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Mining Waste NPL Site Summary Report
The Silver Bow Creek site was added to the NPL in September 1983. Originally, the site
encompassed the Silver Bow Creek floodplain from Butte (downstream) to Warm Springs Ponds.
Remedial Investigations were initiated in this area in 1985. In November 1985, the site boundaries
were expanded to include Butte (Reference 1, page 4).
In October 1988, EPA and the Montana Department of Health and Environmental Sciences (MDHES)
released the first Clark Fork Superflind Master Plan to coordinate remedial activities of all four sites
in the Clark Fork Basin. Since February 1990, EPA has assumed the lead role on most of the Silver
Bow CreekfBune Area Operable Units, except for streamside tailings (which are under the lead of the
MDHES (Reference 2, page 2). At present, there are seven Operable Units within the Silver Bow
CreekfButte Area site. These units will be discussed in the next section.
A Phase il Remedial Investigation for the Warm Springs Ponds Operable Unit was completed in May
1989 (see Figure 2). The Record of Decision (ROD) for this Operable Unit was signed in September
1990. According to EPA, the selected remedial alternative, which is designed to control
contamination associated with pond-bottom sediments, surface water, mine tailings, contaminated
soils, and ground water is currently being implemented. In addition, three removal actions are
underway (Mill Willow Bypass, TravonaiWest-Caxnp Pond, and Butte Priority Soils). Remedial
Investigations are underway for the Streamside Tailings, Rocker Timber Plant, and Butte Mine
(Berkeley Pit and underground mines) Operable Units. The Butte Mine Feasibility Study is scheduled
to be completed by 1993 (Reference 11, page 1).
OPERATING HISTORY
In the years following the discovery of gold (in 1864), the Butte area became an internationally
recognized mining center with over 300 combined copper and silver mines and 8 smelters in operation
by 1884. The Butte area has been mined almost continuously for 110 years (Reference 1, page 4).
Most of the ore mined in Butte was shipped 26 miles west to the smelting complex in Anaconda,
Montana (a separate Superfund Site); however, ore was also smelted in any of eight smelters in the
Butte area. Smelting continued in the Butte area until the Washoe Smelter became operational in
Anaconda in 1902 (Reference 8, page 3). By the 1950’s, the Anaconda Company (purchased by
Atlantic Richfield Comj,any in 1979) had consolidated all mining activity in the area.
Copper, silver, gold, zinc, lead, manganese, and molybdenum have been mined by both underground
(vein) mines and open-pit mines in the Butte area. Major underground mining activity took place
from the late 1880’s through 1960. Over 3,500 miles of underground workings exist in the area;
some of the vein mines reached over 5,000 feet in depth (Reference 1, page 4). The Berkeley Pit, an
3-
-------
P J T
POINT IOI CU
NAN rflINt W*NICI
(jWIIM) WARM DS 4UARG&.
AND M*IALI MIINOII
SILVER 60W CREEK
SITE SCHEMATIC
WAHU SPAINGS PONDS
riAslAft fly StUDY
I
WARM SPRINGS
PONDS
OPERABLE UNIT
ISAN UTIE
u.aM IUY
PIT
WAJIM SMINDI
TUIADINI P0II
I
I
I
I
A1LJSAL
NOT TO SGM l
KEY MAP
MAP 2
-------
Mining Waste NPL Site Summary Report
open-pit mine, operated from 1955 to 1982. It is estimated that over 3,500 miles of underground
mine workings are interconnected with the Berkeley Pit. The pit is over 1 mile deep and 1.5 miles
wide at the rim. Mining companies installed a pumping system to dewater the underground mines
and the Berkeley Pit during active mining . In the 1950’s, bulkheads were installed underground to
inhibit the flow of water between mines and the pits and create two underground flow systems, the
east camp (includes the Berkeley Pit) and the west camp (see Figure 3). These bulkheads were
installed to improve the efficiency of pumping operations (Reference 1, page 4).
In 1964, a mill was constructed in Butte to concentrate the copper sulphide ore from the Butte mines.
High-grade ore was processed through the mill and smelter, while lower-grade ores were leached with
acid water from the mines in large leach dumps located near the tailings disposal area. The mill
tailings were impounded behind a 2-mile-long dam northeast of the mining operation (Yankee Doodle
Tailings Pond). Prior to 1911, when pollution control measures were first initiated, all mining,
milling, and smelting wastes were discharged directly to Silver Bow Creek (Reference 9, page ES-i;
Reference 10, page 2).
The first pollution control measures consisted of ponds created by dams built to trap and settle the
mining wastes (sediments, tailings, and sludges). In 1911, a 20-foot high dam was erected on Silver
Bow Creek, creating Warm Springs Pond 1. Another dam, 18 feet high, was erected on the creek in
1916, creating Warm Springs Pond 2. (This dani was extended to a height of 23 feet.) A third dam,
28-feet high (built between 1954 and 1959), was primarily for sediment control. This dam was
eventually raised to 33 feet. In 1967, Pond 3 was converted to treat mill losses, precipitation plant
spent solution from Butte operations, and overflow from the Opportunity Ponds. Treatment consisted
of adding a lime/water suspension to raise the Ph of the surface water in Silver Bow Creek and
precipitate heavy metals in Pond 3. The three ponds are currently used to physically, chemically, and
biologically treat Silver Bow Creek surface water through sedimentation and chemical and biological
precipitation of heavy metals (Reference 10, page 3).
Mining activity in the Butte area continued until 1982, when the Berkeley Pit was closed (Reference
9, page ES-i). At this time, the pumps dewatering the mine were shut down and the underground
mines began to flood. As the water levels reached the bottom of the Berkeley pit, it began to fill
(Reference 5, page 1). In 1986, mining activity resumed, although on a smaller scale. The
Continental Pit, operated by Montana Resources, produces approximately 50,000 tons per day of
copper/molybdenum ore; New Butte Mining, through its underground operation, produces
approximately 500 to 1,000 tons per day of silver, lead, and zinc ore. Montana Resources operates
an onsite mill to concentrate its ore, discharging the tailings to the Yankee Doodle Tailings Pond
area; New Butte Mining ore is shipped offsite for milling and smelting.
5- -
-------
Silver Bow CreeklButte Area Site
BIG BUTTE
9
WEST CAMP
MONTANA
AREA TEC)4
- I. v1s
MAP3
FIGURE 3. BUITh AREA
6-
2
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Mining Waste NPL Site Summary Report
SITE CHARACTERIZATION
The wastes generated by mining , milling, and smelting activities are sources of contamination for
soils, surface water, and ground water. Contamination is occurring through blowing dust,
contaminated runoff and contaminants leaching through the soil into the ground water (Reference 1,
page 4). The Silver Bow Creek/Butte Area site is divided into seven Operable Units. The Operable
Units are:
• Warm SDrin!s Ponds - Three settling ponds were built in 1911, 1916, and 1959 for the
purpose of trapping mining wastes in Silver Bow Creek before the contaminated water reached
the Clark Fork River (Reference 2, page 2). The ponds (still in use) operate by settling out
tailings particles and other solids and reducing the concentrations of the dissolved metals.
They now cover an area of approximately 4 miles square and contain 19 million cubic yards of
submerged and unsubmerged heavy metal contaminated sediments and tailings (Reference 9,
page ES-2; Reference 10, page 2).
The Mill-Willow Bypass, a subunit of Warni Springs Operable Unit, is a diversion ditch that
routes water around the ponds and into the Clark Fork River. Tailings and contaminated soils
wash into the bypass during summer storms, carrying heavy metals into Clark Fork River.
These heavy metals are suspected to have caused fish kills in the bypass and upper Clark Fork
River (Reference 2, page 2).
• Streamside Tailings - Mine tailings have been deposited on the banks of Silver Bow Creek
between the Colorado Mill Tailings Pile and the Warm Springs Ponds. Vegetation is absent in
these areas, making the tailings susceptible to wind and water erosion (Reference 2,
page 2).
• Rocker Timber Plant - The Rocker Timber Framing and Treatment plant was in operation from
the early 1900’s to 1956. The plant treated mine timbers with a preservative containing
arsenic. In addition, creosote was used at this plant to treat poles and to lubricate skids for
mine timber loading and unloading. Waste material from the pressure treatment was dumped
along the banks of Silver Bow Creek. Surface soils at the plant were found to have high levels
of arsenic (Reference 12, page 18).
• Butte Mine Flooding - The areas included in this Operable Unit are the Berkeley Pit and the
underground mines. The mines are flooding and the pit is filling with acidic mine water
containing heavy metals, sulfates, and arsenic. If left unchecked, the mine water may
discharge to shallow ground water and surface water (Reference 2, page 3). In 1989, EPA
began pumping water from the Travona Mine shaft to prevent it from flooding basements and
running into Silver Bow Creek (Reference 2, page 3). ELevated levels of arsenic and other
heavy metals were detected in ground-water samples taken from the Travona Mine Shaft
(Reference 3, page 1).
7-
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Silver Bow Creek/Butte Area Site
• Butte Priority Soils - This Operable Unit includes 36 cont2minated soil sites in Butte that pose
a potential threat to human health and the environment. Contaminants include lead, zinc,
copper, cadmium, and arsenic. The soil areas vary in size, location, and composition. The
sources of contamination are being addressed in this Operable Unit. Sources include waste
rock dumps, smelter wastes, or tailings piles. This Operable Unit includes the Colorado
Tailings Area along Silver Bow Creek and the Butte Reduction Works (Reference 2, pages 3
and 4).
• NpnDripritv Soils - This Operable Unit includes potential human health risks from contaminated
soils in the nonresidential areas of Butte (Reference 7, page 36).
• Active Mining Area - This Operable Units includes the active mining operations in the Butte
area. The problem areas include fugitive dust emission sources; source areas of acid mine
drainage discharge to the Berkeley Pit; impacts on wildlife from exposure to mining waste; and
potential human exposure to contaminated soils (Reference 7, page 36).
Sells
Soil sampling indicates that the soils at the site contain elevated levels of lead, arsenic, copper,
cadmium, and mercury (Reference 6, page 1). Soil contamination in the Silver Bow CreekfButte
Area Superfund Site is concentrated in two areas. The first area of contamination is the alluvial soil
along the Silver Bow Creek floodplain between Butte and the Warm Springs Ponds. This area is
defined as the Streamside Tailings Operable Unit. The tailings that cover the soil occur primarily on
lower terrace levels along the stream channel, where they have undergone active erosion and
redeposition. The second area of soil contamination involves surface soils and sediments (in areas
farther removed from the stream banks) contaminated by mine and mill tailings and acid mine-water
discharges. These areas are the Warm Springs Ponds, the Rocker Timber Plant, and the Butte
Priority Soils Operable Units.
In May 1988, EPA and MDHES completed the Butte Area Soils screening study. The study showed
metal levels to be highest at old mill sites and mine waste dumps. Residences located near mine
wastes tended to have higher metals levels in their soils, than those in other parts of the city. A Butte
Priority Soils Study was then conducted, which covered 36 areas of Butte that pose a potential threat
to human health and the environment due to the high concentrations of arsenic, cadmium, copper,
lead, mercury, and zinc in the soils (Reference 1, page 5). Two subunits within the Butte Priority
Soils Operable Unit, Walkervile (residential area) and Timber Butte Mill, were found to have
mercury and lead contamination. In Walkerville, mercury vapor was found in residential basements.
At the Timber Butte Mill, high levels of lead were found in the soil (Reference 4, page 6).
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Mining Waste NFL Site Summary Report
Surface Water
Contanlin2red soils and tailings pile leachates from the Warm Springs Ponds, Streamside Tailings,
Rocker Timber Plant, and Butte Priority Soils Operable Units have contributed to the surface-water
contamination of Mill Creek, Willow Creek, the Mill-Willow Bypass, Silver Bow Creek, and the
Clark Fork River (Reference 11, pages 2-23 through 2-2 8). Results from the Phase I and Phase II
Remedial Investigations (conducted in 1987 and 1989, respectively) indicated that concentrations of
heavy metals in Mill, Willow, and Silver Bow Creeks exceed State water-quality standards (Reference
10, page 5). It is possible that these exceedances are a result of three sources (ground-water inflow,
surface-water inflow, and mobilization of mine wastes deposited in the streambed). Ground-water
inflows have contributed to the contamination of Silver Bow Creek at the reach between Montana
Street and the Colorado Tailings Pile. Large increases in copper, zinc, sulfate, arsenic, and cadmium
loads are apparent in this reach of the Creek (Reference 12, page 27).
Monitoring data for the Warm Springs Ponds shows that the ponds provide 50 to 90 percent removal
of metals from the pond influents. Despite this removal/treatment, sampling performed in 1987 and
1988 indicated that the pond effluents frequently exceeded Ambient Water Quality Standards for
cadmium and iron. Ambient Water Quality Standards for copper, lead, and zinc were also
occasionally exceeded in the pond effluents, particularly during the winter months. It should be noted
that no sampling was conducted during high runoff events, which cause inflows to be diverted around
the pond system (Reference 11, pages 2-12 through 2-14).
Warm Springs Ponds pose a further risk to the Clark Fork River because they are susceptible to flood
and earthquake damage, which potentially could release millions of cubic yards of tailings,
contaminated sediments, and metal precipitates into the River. The Ponds are not strong enough to
withstand a moderate earthquake, and a 100-year flood could seriously damage the berms supporting
the ponds.
Ground Water
Ground-water studies involve the Butte Mine Flooding and the Warm Springs Ponds Operable Units.
The first Operable Unit 14 is miles square and includes the Berkeley Pit, the Yankee Doodle Tailings
Pond, the Montana Resources Leach Dumps, the Weed Concentrator, all mine workings, and all
surface areas draining into the mine workings (Reference 5, page 1). EPA is concerned with the
Butte Mine Flooding Operable Unit because the flood waters are highly acidic and contain high
concentrations of copper, iron, manganese, lead, arsenic, cadmium, zinc, and sulfates. If the water
continues to rise in the Berkeley Pit, contaminated water may eventually flow into shallow ground
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Silv Bow Creek/Butte Area Site
water (alluvial aquifer) and to Silver Bow Creek, creating the potential for significant environmental
impacts and human health problems (Reference 5, page 1).
Shallow ground water in the area of the underground mines was tested in 1986 and 1987, and was
found to contain arsenic, cadmium, and other contaminants (Reference 10, page 6). During the Phase
I Remedial Investigation (1987), it was found that Federal Drinking Water Standards (DWSs) were
exceeded for arsenic, cadmium, copper, iron, zinc, and sulfate at several domestic wells (Reference
12, page 27 and page 32).
An additional ground-water problem exists below Warm Springs Pond 1 and in the area of the Mill-
Willow Bypass. Monitoring data collected from the shallow aquifer below Pond 1 and the bypass
indicates exceedances of Montana’s Maximum Contaminant Levels (MMCLs) for cadmium,
manganese, iron, and sulfide. The MMCL for arsenic was also exceeded in the shallow aquifer
below Pond 1. Monitoring data for deep wells at both locations demonstrate exceedances of MMCLs
for manganese and sulfide. The MMCL for iron was also exceeded in the deep wells below Pond 1
(Reference 11, pages 2-17 through 2-19).
Air
Mine-waste dumps and dried-tailings piles are susceptible to wind-blown erosion, and pose a threat to
air quality in the area. Potential exposure pathways are inhalation of contaminants from wind-blown
dust and direct contact with contaminated soils.
ENV1RONMEr ff AL DAMAGES AND RISKS
Investigations into the environmental problems associated with mining activity in the Upper Clark
Fork area were conducted first by the Potentially Responsible Party (PRP) (Anaconda Minerals
Company) from 1966 to 1982. EPA initiated the Remedial Investigation/Feasibility Study process in
1983. An Initial Remedial Investigation for the Silver Bow Creek site prior to inclusion of the Butte
area was completed in 1987.
EPA established priorities to ensure the most serious problems were dealt with first (i.e., areas
involving potential human health risks were given a higher priority than environmental risks). The
four Operable Units at the Silver Bow Creek/Butte Area Superfund Site which are considered jg
priorities are: (1) Warm Springs Ponds; (2) Rocker Timber Plant; (3) Butte Mine Flooding; and
(4) Butte Priority Soils. The Streamside Tailings Operable Unit is considered an intermediate priority
(Reference 1, page 5).
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Mining Waste NPL Site Summary Report
The ROD for the Warm Springs Ponds Operable Unit identified the following risks to human health:
• Workers at the Ponds face an increased cancer risk estimated to be 2 x 10 (2 chances in
10,000) due to incidental ingestion of arsenic in contaminated soils, sediments, and tailings.
People at the site for recreational purposes (e.g., hunters, fishermen, bird watchers, etc.) also
face increased cancer risk from exposure to arsenic.
• Workers and people at the site for recreational purposes face additional cancer and noncancer
health risks due to ingestion of lead and other hazardous substances in the contaminated soils,
sediments, and tailings.
• Current residents adjacent to the Ponds face actual or potential risks from contaminated soils,
sediments, and tailings becoming windborne.
• The contaminated ground water below Pond 1 poses a potential threat to ground-water users.
• The berms protecting the Ponds fail to meet current dam safety standards. Their failure (in
flood or earthquake) could result in catastrophic consequences (Reference 11, pages 2-23
through 2-27).
The following environmental risks were also identified for the Warm Springs Operable Unit:
• Periodic fishkills have occurred in the Mill-Willow Bypass and the Clark Fork River, which
were likely due to copper and zinc released from the tailing deposits. Contaminated soils,
sediments, and tailings also pose an unquantifiable chronic risk to aquatic life and wildlife,
both within the Operable Unit and downstream.
• Aquatic life water-quality criteria have been exceeded in water discharged from the Ponds and
water diverted around the Ponds without treatment.
• Berm failure could result in significant environmental consequences for the Clark Fork River
(Reference 11, pages 2-27 through 2-2 8).
Ground-water infiltration into underground mines and the Berkeley Pit could potentially contaminant
the shallow ground-water aquifer and surface water if the water in Berkeley Pit rises beyond 5,410
feet. As of February 27, 1990, the water level was 4,975 feet, and has not, therefore, reached the
critical level. The contaminants of concern are arsenic, cadmium, lead, copper, zinc, iron,
manganese, and sulfates (Reference 5, pages 4 and 5). Wells for domestic-water consumption are
located in the vicinity of the Silver Bow Creek site and draw water from the shallow aquifer.
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Silver Bow Creek/Butte Area Site
Surface water in Silver Bow Creek was sampled to determine levels of heavy metals and the results
were reported in the 1987 Remedial Investigation. For the protection of aquatic life, the
concentrations of total recoverable arsenic, cadmium, copper, lead, and zinc in surface water should
not exceed specific criteria. When these heavy metals were measured, concentrations did exceed the
standards for protection of aquatic life in Silver Bow Creek (Reference 12, page 33).
The West Camp/Travona underground mine-flooding discharges could contaminate Silver Bow Creek
through direct discharge of ground water into Missoula Gulch, which joins Silver Bow Creek. When
pumps for the West Camp mines were shut off in 1965, ground water began to flood basements in the
residential areas south of the mine shafts. An intercept well was drilled in 1965. From 1965 to
1969, water flowed from this well into Missoula Gulch, and then, into Silver Bow Creek (Reference
3, page 2).
Agricultural soils and crops were also affected by the mine wastes from the Silver Bow Creek site.
Circumstantial evidence exists that approximately 5,400 acres of land have been contaminated by
heavy metals to varying degrees, by using Silver Bow Creek or the Upper Clark Fork River water for
irrigation (Reference 12, page 37).
Fish and water fowl were also studied during the 1987 Phase I Remedial Investigation. There is
evidence thatfish, particularly Rainbow Trout, are receptors of heavy metals within the study area. It
was also found that arsenic concentrations in fish tissue were below U.S. Department of Agriculture
(USDA) food standards (Reference 12, page 46).
REMEDIAL ACTIONS AND COSTS
Remedial actions for each Operable Unit are described below.
Warm Surinas Ponds Operable Unit
As described in the 1990 ROD, the selected remedy for the Warm Springs Ponds Operable Unit
includes controlling contamination associated with pond bottom sediments, surface water, mine
tailings, contaminated soils, and ground water within the boundaries of the Operable Unit. The
following actions are required:
• Allow Ponds 2 and 3 to continue to function as treatment ponds until upstream sources of
contamination are cleaned up. Increase the capacities of Ponds 2 and 3 to receive and treat
flows up to the 100-year flood. Provide for flows greater than the 100-year flood to be routed
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Mining Waste NPL Site Summary Report
around the ponds. Wet portions of Pond 1 will be dewatered, and the pond will be covered
and revegetated.
• Raise and strengthen all pond berms according to specific criteria, which will protect against
dam failure during earthquakes or floods.
• Remove all remaining tailings and contaminated soils from the Mill-Willow Bypass and
consolidate them over existing dry tailings and contaminated soils within Pond 1 (prior to its
closure) and Pond 3. Reconstruct the Mill-Willow Bypass to safely route flows up to half the
probable maximum flood.
• Construct intercept trenches to collect contaminated ground water from below Pond 1 and
pump the water to Pond 3 for treatment.
• Establish surface and ground-water monitoring systems.
• Implement controls to prevent future residential development, swimming, and fish
consumption.
• Delay (for no more than 1 year) decisions related to remediation of contaminated soils,
tailings, and ground water below Pond 1 (Reference 11, pages 1-2 through 1-4).
The estimated cost of these remedial measures is $57,037,000 (for construction) and $379,000
annually (for operation and maintenance) (Reference 11, pages 2-50 and 2-82).
Streamside Tailinas Onerable Unit
The Phase I Remedial Investigation was initiated by MDHES to evaluate levels of contamination in
soils/tailings, ground water, surface water and aquatic animals and plants in Silver Bow Creek (along
with the Warm Springs Ponds). Phase II Remedial Investigation/Feasibility Study activities, which
are building on the initial investigations, are currently ongoing and include a site-wide assessment of
health and environmental risks; evaluation of possible remedies for streamside tailings along Silver
Bow Creek; and additional investigations and remedy evaluations for other Operable Units of the
Silver Bow Creek site.
Butte Priority Soils Operable Unit
EPA replaced heavy metal-contaminated soils with clean soils from 23 homes in Walkerville during
1988. In addition, the PRPs (Atlantic Richfield, New Butte Mining, and the City of Walkervile)
removed and regraded several old mine dumps in preparation for reseeding and fencing. Removal
4 - .
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Silver Bow Creek/Butte Area Site
actions were completed at Walkerville (a residential area) in 1988 and Timber Butte Mill in 1989,
after the Butte Priority Soils Study indicated high concentrations of heavy metals (Reference 4, page
6).
Butte Mine Flooding Operable Unit
A PRP-sponsored Remedial Investigation/Feasibility Study for the Berkeley Pit began in 1990. The
Remedial Investigation/Feasibility Study will be completed in 2 to 3 years, after which clean-up will
be performed. A likely solution is a treatment system for water in the Berkeley Pit and other
underground mine runoff.
In 1989, PRPs began pumping rising water from the Travona mine to prevent contaminated water
from flooding residential basements and entering Silver Bow Creek. Water was discharged (in 1989)
to the Butte Metro Treatment Plant, and was required to meet State water-quality standards and
drinking-water standards for arsenic. Pumping continued through May 1990, and it is still done on
an occasional basis to control the water level in the mine (Reference 3, page 2).
Rocker Timber PLant Operable Unit
The Remedial Investigation/Feasibility Study was initiated during 1990. Approximately 1,000 cubic
yards of arsenic contaminated soils and wood chips were removed in 1989 (Reference 7, page 37).
CURRENT STATUS
Remedial measures began in 1990 at the Warm Ponds Springs Operable Unit. Specifically, the Mill-
Willow Bypass removal action began. According to EPA, a Remedial Investigation/Feasibility Study
is currently being conducted at the Butte Mine Flooding Operable Unit by the PRP. An expedited
response action has been implemented at the Travona Mine site. The response entails pumping of
contaminated ground water from the mine shaft to a Publicly Owned Treatment Works for treatment.
Under the Butte Priority Soils Operable Unit, three soil removal actions have been completed. A
removal is currently underway at the Streamside Tailings Operable Unit. A Remedial Investigation
and Feasibility Study is underway at the Rocker Operable Unit.
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Mining Waste NPL Site Summary Report
REFERENCES
1. Clark Fork Superfund, Master Plan; EPA and MDHES; October 1988.
2. Progress - Clark Fork Basin Superfund Sites; EPA and MDHES; May 1990.
3. Superfund Program Fact Sheet, Silver Bow CreeklButte Area Site; EPA and MDHES;
September 1988.
4. Progress Report No. 2: Clark Fork Superfund Sites; EPA and MDHES; August 1988.
5. Superfund Program Fact Sheet, Silver Bow Creek/Butte Area Site; EPA Region Vifi; May 1990.
6. Superfund Program Fact Sheet, Silver Bow Creek Site, Butte Area; EPA Region Vifi (Montana
Office), May 1990.
7. Clark Fork Superfund Sites: Master Plan; EPA and MDHES, November 1990.
8. Site History of Smelter Hill - Anaconda Smelter NPL Site; Prepared by GCM Services Inc. for
ARCO Coal Company; June 1989.
9. Feasibility Study for the Warm Springs Ponds Operable Unit, Volume I, Draft; MDHES and
CH2M Hill; October 1989.
10. Proposed Plan: Warm Springs Ponds; EPA and MDHES; October 1989.
11. Record of Decision, Silver Bow Creek/Butte Area NPL Site, Warm Springs Operable Unit,
Upper Clark Fork River Basin, Montana; EPA; September 1990.
12. Silver Bow/Butte Site Profile, Document #983-TS 1-RT-I I’1R; Author Not Provided; Undated.
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Silver Bow Creek/Butte Area Site
BIBLIOGRAPHY
Author Not Provided. Silver Bow/Butte Site Profile, Document #983-TS1-RT-ET [ R. Undated.
EPA. Record of Decision, Silver Bow Creek/Butte Area NPL Site, Warm Springs Operable Unit,
Upper Clark Fork River Basin, Montana. September 1990.
EPA and MDHES. Clark Fork Superfund, Master Plan. October 1988.
EPA and MDHES. Clark Fork Superfund Sites, Master Plan. November 1990.
EPA and MDHES. Progress - Clark Fork Basin Superfund Sites. May 1990.
EPA and MDHES. Progress Report No. 2: Clark Fork Superfund Sites. August 1988.
EPA and MDHES. Proposed Plan: Warm Springs Ponds. October 1989.
EPA Region Vifi. Superfund Program Fact Sheet, Silver Bow CreekfButte Area Site. September
1988.
EPA Region Vifi. Superfund Program Fact Sheet, Silver Bow Creek/Butte Area Site. May 1990.
EPA Region Vifi (Montana Office). Superfund Program Fact Sheet, Silver Bow Creek Site, Butte
Area. May 1990.
Forba, Russ (EPA). Personal Communication Concerning Silver Bow Creek/Butte Area Site to Maria
Leet (SAIC). June 27, 1990.
Forba, Russ (EPA). Personal Communication Concerning Silver Bow Creek/Butte Area Site to Maria
Leet (SAIC). October 22, 1990.
MDHES and CH2M Hill. Feasibility Study for the Warm Springs Ponds Operable Unit, Volume I,
Draft. October 1989.
“Montana Standard,” Butte, Montana. February 4, 1990.
Prepared by GCM Services Inc. for ARCO Coal Company. Site History of Smelter Hill- Anaconda
Smelter NPL Site. June 1989.
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Silver Bow Creek/Butte Area Site Mining Waste NPL Site Summary Report
Reference 1
Excerpts From Clark Fork Superfund, Master Plan;
EPA and MDHES; October 1988
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/ C7 1
I.._.. . ......
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PREFACE
1.0 INTRODUCTION
This Master Plan has been developed by the U S Environmen-
tal Protection Agency (EPA) and the Montana Department of
Health and Environmental Sciences (MOHES) It describes
the overalt general approach being used to address concerns
regarding hazardous substances. pollutants, and con-
taminants at the Superfund sites in the Clark Fork Basin The
detailed technical approaches being used at specific Super-
fund sites are described in site-specific workplarls which are
available to the public at Supertund document repositories
throughout the Clark Fork Basin The coordination of these
technical approaches is accomplished through active com-
munication among all Superfund project managers and the
Superfund Coordinator.
The scope of Superfund problems and specific human health
and environmental concerns associated with each site are
discussed in Section 2 and the Appendix of the Master Plan
The Superfund effort in the Clark Fork Basin encompasses
the largest geographic area of all Superfund assignments in
the United States The number and complexity of existing and
potential human health and environmental problems in the
basin require that priorities be set for response actions. The
approach that EPA and MDHES have used to prioritize
response actions is explained in Section 3. This pnontization
process has resulted in identification of three broad categories
of Superfund problem areas problems pnmarily related to
human health, problems which primarily affect the quality of
Silver Bow Creek. and problems which relate primanly to the
Clark Fork River and adjacent areas. The technical and legal
interrelationships among these categories and among sites
are discussed in the Master Plan Section 3 also summarizes
the major accomplishments of the Superfund program at the
Clark Fork sites
Federal laws governing Superfund response actions require
that technical and legal issues be addressed in a well
documented and consistent manner at all sites. The Super-
fund process is outlined and mechanisms available to imple-
ment interim and final response actions are described in Sec-
tiOn 4 The influence of site interrelationships on the process
and schedule is discussed in light of the need for effective.
coordinated response actions. A schedule for addressing
Superfund problem areas, which is based on information cur-
rently available to EPA and1CT ES, is presented in Section
5 This Master Plan will be updated periodically as cleanup
activities progress. EPA and MDHES welcome public com-
ments on the information presqnted in this Master Plan
1.1 GOALS AND OBJECTIVES
This Master Plan has been prepared for public distribution tiy
the U S Environmental Protection Agency (EPA) and the Mon-
tana Department of Health and Environmental Sciences
(MDHES) to provide a better understanding of the overall
approach being used to manage Superfund activities in the
Upper Clark Fork Basin of southwestern Montana These ac-
tivities are being conducted under authority of the Com-
prehensive Environmental Response. Compensation and
Liability Act (CERCLA) or “Superfund” which was passea by
Congress in 1980 arid amended in the Superfund Amend-
ments and Reauthonzatjon Act of 1986. Appropriate state
authorities are also utilized in the Superfund process
Superfund activities in the Clark Fork Basin are focused on
reducing risks to human health arid the environment from the
release or threatened release of hazardous substances.
pollutants, or contaminants primarily from past mining and
smelting activities
Other Federal. State. and local agencies are also conductng
natural resource investigations in the Basin These investiga-
tions have been summarized in a report prepared by me
Governor’s Clark Fork Basin Project (Johnson arid Schmt t
1988) In addition to integrating appropriate information from
these investigations. Superfund activities in the Basin must
be conducted in a specified manner as required by CERCLA
and the National Contingency Plan (NCP)’ which guices
technical implementation of Superfund activities
To ensure that effective response actions are achieved Super.
fund activities must be coordinated so that the technical aid
legal requirements of CERCLA and the NCP are met In ad•
dition, consistent approaches to response actions must e
followed since study results and response actions at one loca-
tion will affect these activities at other contaminated sites To
assist in coordinating response actions in a technically aric
legally-consistent manner. EPA has developed guidance for
the Superfund program throughout the country Interpretation
and application of this guidance to achieve appropriate con-
sistency among sites is achieved through active communica-
tion among the Superfund project managers, the Superfurid
coordinator, and other staff.
This Master Plan was developed to aid the public in uricer-
standing how requirements of the Superfund process relate
to response actions which are being planned or implemented
at the Supertund site. Some specific objectives of the Master
Plan are to:
identify, prioritize, and coordinate inter-site activities to
achieve the most rapid and effective investigation and
where necessary, remediation of the Clark Fork Superfund
sites as possible;
I Terms whicfl aopeai in bold ?ac Iy s on firs mention are detned r ‘e
glossary on pass 11 01 ll’*is documere
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• coordinate Superfund activities with otner environmental im-
provement programs.
• provide for consistent approaches to response actions for
all sites.
• communicate information on Superfund aCtMtieS to all in-
terested parties
A projected schedule for addressing contamination problem
areas is included in this Master Plan This schedule will, of
necessity. be modified and updated as new information
becomes available and major decisions are made
1.2 HISTORICAL BACKGROUND
The EPA and the State of Montana are working together in the
Superfund program to seek solutions to the impacts from
hazardous substances (pnmanly metais) left by over 100 years
of mining and processing operations, as well as other in-
dustnal activities. The area of concern includes the Upper
Clark Fork Basin above Warm Spnngs Creek and the main
stem of the Clark Fork River to the Bitterroot River below
Missoula. Montana.
Investigations in the upper Clark Fork area, initiated by EPA
in 1982. resulted in tl ’ establishment of tour separate but con-
tiguous Superfund sites. The sites are the Milttown Reservoir
site, the Anaconda Smelter site, the Montana Pole site. and
the Silver Bow Creek/Butte Addition site (See Map. page 2)
EPA and MOHES initially identified 77 existing or potential con-
tamination problems at the sites As described in Section 3,
these problems have been consolidated where possible for
more efficient responses. EPA has provided funds to MDHES
to take the lead for investigations at the Silver Bow Creek site,
the Montana Pole site, arid the Milltown Reservoir site. The
Atlantic Richfield Company (ARCO) is conducting investiga-
tions at the Anaconda Smelter site and may undertake work
at other sites EPA also intends to offer the opportunity to
potentially responsible parties to conduct the investigations
for the Butte Addition to the Silver Bow Creek site under an
enforcement agreement (see Section 4.4 SuperfundEnfoi’ce-
merit Authorities) EPA is managing response actions for the
Butte Addition
In an effort to develop an integrated approach for addressing
these sites. EPA. MDHES. the Montana Governors office.
representatives from the commur itles of Butte and Anaconda.
and the Atlantic Richfield Company (ARCO) have provided in-
put to this Master Plan to help define investigation and
remedial priorities and establish a schedule for coordinated
action.
2.0 PROBLEM AREA DEFINITION
Each Clark Fork Superfund site is comprised of several ex-
isting or potential contamination problems. The most impor-
tant problems are summarized for each site in the Appendix
The history arid interrelationships of problems among sites are
descnbe i further in the narrative below The major corrective
actions that have already been taken at each site are des-
cribed in Section 3.3.
2.1 MIU.TOWN RESERVOIR SITE
Milltown Reservoir is located adjacent to
Militown, Montana at the confluence of the
Blackfoot and Clark Fork Rivers Milltowri
Reservoir was created in 1907 as part of a
hydroelectnc power generating facility which has been owned
and operated since 1929 by Montana Power Company The
reservoir has accumulated 6.5 million tons of sediments
transported by the Clark Fork River and its tributanes
(Woessner et al. 1984). Unusually high concentrations of
arsenic, lead, zinc, cadmium, and other metals have been
found in reservoir sediments These contaminants have been
transported from the reservoir sediments into the shallow
ground water that provided drinking water for Militown
residents. The reservoir was designated a Superfund site ri
September 1983.
2.2 ANACONDA SMELTER SITE
The Anaconda Smelter is located at the
southern end ot the Deer Lodge Valley ao-
proximately 25 miles northwest of Butte
Ore from the Butte area mines was transported to Anaconda
and processed at various locations (Old Works. Arbiter Plant.
and Smelter Hill) from 1884 to 1980. Ore processing wastes.
including about 185 million cubic yards of tailings, about 27
million cubic yards of furnace slags, and about 250.000 cubic
yards of flue dust (CH2M Hill, October 1984), are contained
within an area of more than 6,000 acres and contain elevated
concentrations of copper, cadmium. arsenic, lead. and znc
The Anaconda Smelter area was designated as a Superfuria
site in September 1983.
Tailings were typically deoos’ted in ponds where SOlidS were
allowed tO settle before the wastewatet was recycled or
released into nearby watercourses. These ponds (AnaconOa
Opportunity, Bradley. and Iron) were created by a series of
dikes which have left mounds of tailings as deep as 90 feet
These ponds contain various wastes which have led to ground
water and surface water quality degradation Additionally.
emissions from the smelter stack have resulted in soils con’
tamination throughout a broad area of the upper valley
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2.3 MONTANA POLE SiTE
The Montana Pole site encompasses approx-
imately 40 acres immediately south of Silver
Bow Creek at the southweSt edge of Butte
From 1947 to 1983 the Montana Pole Treating
Company treated poles with pentachlOrOpheflOl (PCP) and
creosote at this site In 1983. seepage of these wastes from
the Montana Pole site into Silver Bow Creek was estimated
to be two to five gallons per day The site was designated a
Superfund site in November 1986.
2.4 SILVER BOW CREEK!
BUTTE ADDITION SITE
Following the discovery of
gold in 1864, the Butte area
became an internationally
recognized mining center with over 300 combined copper and
silver mines. 9 silver mines, and 8 smelters in operation dur-
ing 1884 In 1955. excavation of the Berkeley Pit began and
mining continued until 1977. Silver Bow Creek has historical-
ly received discharge from mining, smelting. wood treating.
arid other industrial sources for over 100 years
The Silver Bow Cre’ek site was designated a Superfund site
in September 1983 The original site encompassed the
floodplain of Silver Bow Creek from Butte downstream to the
Warn ’ Spn rigs Ponds. Remedial investigations were initiated
within this area during 1985. In November 1985. the boun-
daries of the site were expanded to include the Butte area.
Downstream portions of the Clark Fork River floodplain from
Warm Springs Ponds to MilItown Reservoir were identified as
an expanded study area
Today mining, milling, and smelting wastes exist as sources
of soil, watei and air contaminatiOn throughout the Butte area.
Contaminated surface water runoff from the Butte area
discharges directly to Silver Bow Creek. In addition.
underground mines in the area are filling and generatrng acid
water as water revels rise. During active mining, these mines
were dewatered by a network of pumps with some water be-
ing recycled and some ben ttarged to Silver Bow Creek.
It is estimated that over 3,500 miles of underground mine work-
ings are interconnected with the Berkeley Pit. These mines
contain approximately 11 2 billion gallons of acid mine water
(CDM 1988) Initial investigationS suggest that within eight
years at the earliest, water in the Berkeley Pit may rise to a
level where acid mine drainage could contact the
bedrock/alluvium interlace with the possibility for contaiyiina-
tion of Silver Bow Creek
In addition tO contaminants from the Butte area. the Montana
Pole and Rocker wood treating sites contribute to the contami-
nant load of Silver Bow Creek Continuous deposits of metals-
laden sediments and tailings lie within the floodplain and con-
k
taminate surface and ground water along Silver Bo Creek
and the Upper Clark Fork River The Anaconda Smelter site
also has contributed contamination to the Clark Fork River
2.5 INTERRELATIONSHIPS AMONG SITES
Geographic, technical, and legal interrelationships among
Superfund sites in the Clark Fork Basin dictate that close coor-
dination will be required during implementation of this Master
Plan Due to their geographic proximity. all Superfund sites
are sources of contamination to Silver Bow Creek and/or the
Clark Fork River. As a result of this interrelationship, response
actions need to be coordinated so that downstream. dow’l-
gradient. or downwind sites are not recontaminated, follow-
ing cleanup, by upstream, upgradient. or upwind sites
Another similarity among these sites is the problem of deal-
ing with large volumes of mining wastes which contain similar
metallic contaminants. The sites also share similar pathways
through which human health and the environment are
adversely affected. Due to geographic proximity and
similarities of waste characteristics, response action criteria
which are established for these sites will be closely related
For the same reason, response actions appropriate at one
mining waste site may also be appropriate at other sites
All of these interrelationships among Superfurid sites in the
Clark Fork Basin require that response actions are carefully
coordinated to ensure that effective solutions are identified
and implemented in an appropriate sequence The overall pur-
pose of this continuing master planning effort is to ensure that
activities being conducted at individual sites complement
each other and lead to the most efficient response possible
3.0 ADDRESSING OPERABLE UNITS
In order to manage the interrelated problems identified at the
four Clark Fork Superfufld sites. EPA and MDNES have con-
solidated the 77 potential contamination problems into 25
Opefable Units, An operable unit is a clearly defined, smaller
portion of the overall work to be completed at a Supertund site
Each operable unit is generally investigated and remeaiated
on an individual basis. The cntena used to designate operacle
units are
• Areas with similar contaminated media (soils flue ouSt.
ground water. etc.);
• Areas within a similar geographic area;
• Areas that will be remediated using similar techniQues.
• Areas that will be remediated within a similar time “ame
and
• Areas that can be managed and addressed as an ircivcual
Rl/FS
4.
-------
thea. 25 operable units VS sijb9eot to change as more infor.
natiO becomes available. For example. it may be poSsible
co further cOniOl1d operable units if additional similarities
atV 44 widindUal unite VS ,dsitbflsd, or further invsengauon
may show that the consolidated Operable units m at be broken
oack down untO smaller. more manageable units to carry out
aropriate remedies.
3.1 CRITERiA FOR ESTABLISHING PRIORiTiES
Since there are so many Superfund problems tO be
addressed, priorities are established tO ensure the most
serious problems are dealt with first. The EPA and MOHES
have identified high, medium, and low priority operable units
according to the sequencing criteria listid in Thole 1.
Table 1:
Crttsf 1$ for Establishing PriorIties for Operable Unite
High Priority Sequencing Ci1ted
1. High potential human health exposure
2. Nigh potential environmental exposure
3. Provides critical-path data ne.ded to fully address
other operable units
Medium Priority Sequencing Critda
1 Medium potential human health exposure
2. Medium potential environmental exposure
3. PownUal for recontamination of other operable units
located downstream, downgradlent. or downwind
4 Unusually complex problem requinng lengthy
evaluation
Low Priority Sequencing Critsds
1 Low potential human health eiposure
2. Low potential environmental expoSure
3. Low present human health or environmental su.
posurs but potential future po.ure
4 Low risk of off-sits contamination
The sequencing criteria are rifled ecoording to several I
lore. Human exposures its generally given a higher raflang
tnan other cnteni ”TWere is recognition that some human
he i concerns pass an immediate health risk that should be
Thai with as a removal a on . Other health owiciems involve
chronic nals owr a Istku1I of & QIiwe that can be reiponded
to with a later. longer-term addon. In total the sequencing
criteria provide for the orderly resolution of human health and
environmental concerns at the Superfund sites.
3.2 RANKING OPERAeLE UNrTI
Each of the 25 operable units wes evaluated against the
criteria shown above and placed into a high, medium, or t
priority eatigomy . This ranking Is praunhid in Table 2. Each
of these operable units is shown on ths ma r schedule in
Seaion 5
3.3 COMPUSHMENTS
A significant amount of rk has already occurred on r
of these operable unite. This secilon briefly summarize
efforts to date.
3.3.1 MflhIo n Reservoir Site
In 1983 a Remidlal InvesdgetioniFeas
ty Study (RIIF$) was initiated by MO
and EPA. As a re uft of these studies.
provided funds for a new water supply sy
for Milltown in 1985. RLIFS activities are continuing at Mill’
under the lead d.reaion of MOHES. These studies will adc
the need for. and possible solutions to, the contaminated ri
voir sedimem and ground st Mfltown. In addition, ti
studies are being expanded to determine if releases of h
dow substances, pollutants, or contaminants have occu
or have the potential for occumng downstream from
reservoir.
.5.
Table2
Ust of PrIorities of
Clark Fork
Operable Units
High Priority Operable Units
urn Creek
W l e
Butte Priority Soils’
Old Wadis Removel
Fiue Dust
Warm — Ponds
Montana Pole
Mine Flooding (Bedeuey Pit)
Rocler
Medium Priority Operable Units
SBC Ares I (Metro Storm Drain—Colorado Tailinç
Stjumslds $lngs ( Colorado ThllngaWarm Sprin
Smelter NM
Clark Fork R
MUltown volr
An.condmUnhty Sofia
Anaconda Slts.wide Ground Water
Old Wads (General)
Low Priority Operabls Units
Suite N Pdonly Sods
Tailings (ground w dalluvtum)
Smelter Wulss (Beryllium, Slag)
Anaconda Surface Water and Sediment
— Lands
dve Mine Me&
on J .iieIS ui S __.. in boI0tl r qi .i ’ ‘s ncIi.
ie I’II I uld moe iflediim U11 i1I ’v O VI IS .
-------
Silver Bow Creek/Butte Area Site Mining Waste NPL Site Summary Report
Reference 2
Excerpts From Progress -
Clark Fork Basin Superfund Sites;
EPA and MDHES; May 1990
-------
PROGRESS
of metals to soils and waters.
The Li S. Environmental Protection Age r.c
(EPA) and the Montana Department of Kealth ar
Environmental Sciences (MDHES) investigate a -.d
clean up Superfund sites in Montana Periodi-
cally. the agencies produce public Information
site activities. This progress report Summarizes
current Clark Fork Basin Superfund act1v t!es
where the public can obtain more inforrnat ct
and how they can get more Involved in the St.. :e-
fund process.
Clark Fork sites have colorful history
Four Superfurid sites lie In the Clark Fork
Basin from Butte to Mlssoula. 138 rIver miles.
The Clark Fork sites include the Silver Bow
Creek/Butte Area. Montana Pole. Anaconda
Smelter and Milltown. Except for the Montana
Pole site. contai’ntnatlon at the sites Is primarily
mining wastes and he yy metals-laden søils and
water. The Montana P iie site which lies adjacent
to the Silver Bow Creek/Butte Area site in south-
western Butte is contauliriated with wood treating
wastes
EPA and MDHES have designed a coordi-
riated plan emphasizing efficient Invesugaflon and
cleanup of the sites. In 1988. EPA published a
Clark Fork Master Plan. This summer, EPA will
publish an updated and expanded Master Plan.
Both the coordinated plan and the Master Plan
prioritize the activities of 25 operable unhts and
77 smaller problem areas of the Clark Fork
Superfund sites. The Master Plan also includes
work underway by other agencies conducting
studies In the basin.
Silver Bow Creek/Butte Area
Montana Pole
Anaconda Smelter
Militown Reservoir Sediments
Document repositories
Superfund hotline
Offiicial contacts
Clark Fork map
2
4
5
6
7
7
8
May 1990
Clark Fork Basin Superfund Site
By the Montana Department of Health and Environmental Sciences
and the U.S. Environmental Protection Agency
Introduction
Superfund remedjation activities are pro-
gressing at a rapid pace this spring In the Clark
Fork Basin Superf’und sites. Major events Include
accelerated cleanup of the Mill-Willow Bypass.
emergency soils removal in Butte, and a study of
the Coloradp Tailings, which Is scheduled for
cleanup in 1991. More than 100 years of mining
have left a hazardous legacy along Silver Bow
Creek and the Clark Fork. Millions of tons of
tailings. rich in heavy metals, have contaminated
soils, groundwater and surface water. Planned
remedlat ion activities will lessen the contribution
Printed on recycled paper
-------
Silver Bow Creek/Butte Area
The Silver Bow Creek/Butte Area site gener-
ally includes Walkerville. Butte. the BerkeleY Pit.
Silver Bow Creek. Rocker. the Warm Springs
Ponds and the Clark Fork River to the Militown
Reservoir. about fIve miles southeast of Missoula.
The Silver Bow Creek site officially became a
Superfurid site in 1983 when it was added to the
National Priorities List of Superfund sites. Min-
ing. milling and smelting wastes. primarily heavy
metals. have contaminated thousands of acres of
flood plain and streambariks as well as residential
areas in Butte. The wastes are to tic to plant and
aquatic life and may pose a threat to human
health.
Since Februaiy 1990. EPA has assumed the
lead role on all Silver Bow Creek Investigations
except for studies of streamside tailings which
remain under MDHES lead. The main potentially
responsible party. ARCO. will be gi rvn the oppor-
tunity to conduct the actual remedial investiga-
tions and feasibility studies for all Silver Bow
Creek operable units. EPA may offer the respon-
sible parties the opportunity to conduct site
investigations and cleanup. ARCO will conduct
its investigations In compIt ive with work plans
developed or approved by. and under close super-
vision of. EPA and MDHES.
Warn SprInR Pon The ponds Wv v
originally built by Anaconda Mining Company
beginning In 1911 wIth the con uCUon of Pond
1. The ponds were designed to U ap and hold
mining wastes flowing dawn Silver Bow Creek and
other streams bdore being released Into the Clark
Fork. MDHES prepüid a fe fhtIlty study and
cleanup plan for the ponds. and held public
meetings and hearings last December to present a
cleanup plan to the public. MDHES Is now
preparing detailed responses to the numerous
cor ents received.
In addition. ARCO developed a somewhat
different alternative for cleanup of the ponds and
presented it to MDHES and the public. MDMES
and EPA are viewing the merits of ARCO’s plan
In detaiL As a result of the public coents and
ARCO’s proposed plan. the final cleanup of the
ponds is likely to be a combination of plans. The
final cleanup approach will be uncertain until
EPA completes the Record of Decision which will
PROGRESS
speU out the selected cleanup plan. Improve-
ments to the pond berms to protect them from
earthquake and flood hazards will begin this
summer. with other improvements to the pond
systems to begin In 1991. The proposed cleanup
is expected to defer decisions about the riced for
an upstream flood management Impoundment
and the adequacy of utilizing Pond 3 for treat-
ment of flood flows until 1995. when operating
experience and other Superfund activities up-
stream can better define the viability of ARCOs
proposed treatment approach.
Mill-Willow BypuL Because EPA and
MDHES suspect the Mill-Willow Bypass is the
major area responsible for fish Itills in the upper
Clark Fork. ARCO has begun to ident1 arid
Isolate tailings and contaminated soils that wash
into the bypass and upper Clark Fork during
su1m1 er storms. A work plan for removal of these
wastes is being developed now and cleanup is
projected to begin in the bypass late this summer.
.- ..
“ ‘ tre”u’”4de T 41hig : Large amc unts of
tailings have been deposited on the banks of
Silver Bow Creek between the Colorado Tailings in
Butte and the Warm Springs Ponds. Because
vegetation will not grow in these contaminated
areas, they are typically bare and are susceptible
to wind and water erosion. MDHES is currently
investigating one alternative to revegetate these
tailings to prevent erosion arid movement of
contaminants. In addition, a remedial investiga-
tion and fe 1h1I1ty study, which will begin this
year and last about two years. will consider
several alternatives for handling tailings deposits
in the streambed including removal. rechanneling
the creek. revegetation and combinations of these
alternatives. The Streambank Tailings and
Revegetatlon Study (STARS) test plots are part of
this thvestigatio
— I•
Clirk Pork Rlver Tailings have been de-
posited at numerous eath n along the Clark
Fork River between the Warm Springs Ponds and
Militown Rgservo . MDMES conducted a prelinli-
nary survey of cont 111th2tion along the Clark
Fork. The results of this survey will be available
this sun er . EPA Is planning to begin the
remedial tnvest igauonf feasibility study on this
site in early 1991. The upper portion of the river
Site baektronnd
-------
is the site of an ARCO-furided demonstration
project that will test various methods for stablliz-
trig the tailings In place.
Rocker Timber Framing and Treating
Plant: The Rocker plant treated timbers for the
mines in Butte Timber treatment consisted of an
arsenic-based preservative which was resistant to
fire Last fall. MDHES directed ARCO to conduct
an emergency removal of highly contaminated
soils at the site. ARCO completed the removal.
contoured the site and tore down some old. po-
tentially dangerous buildings. ARCO transported
the soils to a disposal site In Oregon. A remedial
investigation will Identify remaining contaxriina-
tion sources at the site. This investigation wIll
begin In early 1991 under EPA oversight.
EPA will develop work plans for these stud-
ies this sun ner. Formal negotiations with re-
sporisible parties will begin this fall, with field
investigations expected in the spring of 1991. and
collective action to begin in two years.
Butte mine flooding: The mine flooding
area ix cludes the Berkeley Pit and underground
mines. Left unchecked. mine flood water may
discharge to groundwater and surface water. The
mine water Is addic and Is contaminated with
heavy metals, sulfates and arsenic. EPA and
several potentially responsible parties. Including
ARC 0. Montana Resources Incorporated.
ASARCO and Washington Corporation have
reached agreement on the Remedial InvestIga-
tlon/Feaslblllty Study Work Plan. EPA has not
reached agreement with several other responsible
parties. All consenting parties have agreed to try
to complete this study by late 1993. ThIs remedial
lrwestlgauon/feasibility study will evaluate alter-
natives for addressing the mm. flooding problem
and determine a critical water level at which the
Berkeley Pit has to be maintained to prevent
contamination from being spread by floodMg .
The Mtne1’ lng Remedial Investigation
will Include the following:
1) Inflow control Investigation - to evalu-
ate the possibility c( controlling flows Into the
Berkeley Pit.
2) Surface water Investigation - to moni-
tor the quality of water at the treated mine water
discharge point Into Silver Saw Creek to deter-
mine whether it meets water quality standards.
3) Synd4 ate Pit evaluation - to evaluate
the effect and po,’thle control of Syt vib te pft
water which flows Into the Berkeley Pit.
4) Butte disturbed soils Investigation - to
determine the effect that contamination from
mine waste piles In Butte has on mine flooding.
5) TailIng darn safety assessment . to
review the safety of the Yankee Doodle Ta1ltngs
Ponds Darn which lies above the Berkeley Pit.
6) Bedrock groundwater monitoring -
monitor water quality In the mines and measure
bedrock water levels. The results of this study
will give the agencies information they need to
determine whether water levels are rising more
quickly than previously believed.
7) Leach pad area alluvial Irlvesugauon.
monitor the leach pad area above the Berkeley Pit
to determine if they are a scurce of groundwater
and surface water contamination.
8) Private well inventory - to tdenti,fv and
possibly monitor all private and rnuruclpal shal-
low wells to coUect Information on groundwater
levels and quality
9) Neutraflza jon Investigation - to
determine if Berkeley Pit water could be neutraJ-
ized by adding mine tailings to it.
Travona/West Camp: In 1989. EPA began
pumping the rising water of the Travona Mine to
prevent the water from flooding basements and.
running Into Silver Bow Creek. The waste water
pumped from the Travona Is discharged to the
Butte Metro Treatment Plant and must meet
water quality standards. including the ‘I classifi-
cation discharges for to c metals and drtnl ng
water standards for arsenic. The Involved respon-
sible parties constructed a pumping and piping
system to the Metro sewer line on Iron Street.
Approximately 200 gallons per minute of the
Travona water has been pumped to the Metro
Plant since January 1990. a total of 40.000.000
gallons from January to May. Pumping stopped
in May because the water level was brought below
the desired control elevation. Pumping will be
Initiated when necessary to keep the water below
the control level.
V Butte priority soiio The Butte priority soils
Include 36 areas of Butte which pose a potential
threat to hiim n health and the environment
because of lead. sinc. copper. ca iiuzn and/or
arsenic. These areas vary In size, location and
composition. Some areas are waste rock dumps.
smelter wastes or tailings. Cleanup of these sites
will proceed In four phases:
1) Thne-crltical removal - During the
1990 and 1991 cori uct1on seasons, one of the
responsible parties. ARCO. will remove or reclaim
10 source areas with a b c of these scheduled for
this sim ner . These 10 source areas cover 12 of
the 36 areas so far identlfled.2) Non tlme-crtuca.L
Cont. on page 4
FROG RES
-------
w
Site haektround
Preliminary Investigations at the Montana
Pole site showed the presence of hazardous
contaminants. Including pentachiorophenol
(PC?) arid dioxin, in site soils and groundwater
The Montana Pole site Is located at 202 West
Greenwood Ave in Butte The facility operated
from 1947 untIl 1984 preservIng poles, posts and
bridge timbers.
Current activities
In June. MDHES begins oversight of a
remedial investigation/feasibility study of the
Montana Pole site. The remedial trivest .Igatlon/
feasibthty study will determine the extent of
contamination, the effects upon human health
w
and the environment, and appropriate cleanup
alternatives. The downstream extent of contami-
nant studies associated with the Montana Pole
site will be to the lower end of the Colorado
Tailings. The Silver Bow Creek Strearnstde Tail-
ings Remedial Investigation will determine if
Montana Pole contaminants have extended
further downstream and if they need to be reme-
diated. ARCO will perform the site Investigations
under MDHES supervision.
A public review period on the Remedial
Invest Igation/Feasibility Study Mmnlnlstrative
Order on Consent will end June 1. 1990. MDHES
and EPA encourage the public to become Involved
in the Superfund process at the Montana Pole
site.
Silver Bow Creek/Butte Area
(Cant. from page 3)
removal - EPA is developing a plan for cleanup of
the residential areas, in Butte and Walkervifle
that are not addressed In the time-altical removal
action.
3) Lower Area I (Colorado Tailings and
Butte Reduction Works) - EPA and ARCO are
developing a plan to address this area with the
goal of cleanup in 1991. An interim remedy will
be selected, consistent with the final remedy, after
public Input. ARCO will conduct this cleanup
action under an order by EPA.
4) Remedial InvestIgation/feasibility
study- EPA and MDHES will address those areas
not included In the time-altical and non time-
critical removals in a remedial lnv’estlgauon/
feasibility study. The Investigation and study will
focus on how storm run-off from Butte may aiTect
health and the environment In the Silver
Bow Creek study area. EPA has prepared a
scoping document and this suner will write a
work plan for remedial InvestigatIon/feasibility
study activities,
Superfund Hotline
If you have questIons. concerns or comments
about the Superfund program. in general. or
about specific sites, call the Montana ioU-free
Superfund hotilne. The hothne Is answered by
Montana Deparin ent of Health and Environ-
mental Sciences Supetfund staff In Helena. and Is
in service 8 a.m. to 5 p.m. weekdays. except
holidays. Un-state use only)
1-800-648-8465
Montana Pole
PROGRESS
4
-------
F ”
Silver Bow Creek/Butte Area Site Mining Waste NPL Site Summary Report
Reference 3
Excerpts From Superfund Program Fact Sheet,
Silver Bow Creek/Butte Area Slte
EPA Region VIII; September 1988
-------
Supertund Program
Fact Sheet
Silver Bow Creek/Butte Area Site
Butte, Montana
September 1988
iNTRODUCTiON
The U.S Environm.n l Pvc e ion
qency ( EPA ) s oop on with the
Montana OepsiVnsnt of Health and En-
—
pissed a study to desermine whedier
mine boding in the 1 Camp awe of
Butse ( see pegs 2 r di uion
Camp) prser*s a threst to public health
or ths eiMronmsi*. and to identify and
& s se p I)le sok lans to the flooding.
The *ady ind tt 1)the p sn-
n iiaud nine rto
discharge i Siher B Creek or the
a1jw s,1 alluvial aqui r 2) the situalion
should be monitored so that ion n
benatthepnipetoawertajch
discharge ; and 3) there are se ri
response ons that could mitigate the
— — uso d with such
ha
EPA *cpo to respond in t
EPA asmnt pr aed itemil ths
first gs is to monisx pound sr
te ,te and diemimsy so that on i
bet ian a tthepdme t oa
di gs ian d r as.
ce or ground v Reeulte from this
g - pubic ut wi he d r-
mine the bming and deign the
scond ge respone The monitoring
be ted to thggsrths iuØme n
of a gs t response that wiN dr
t on one of the hsr fesilbis response
ons duc.t4.d on pegee 2 and 3 of
this shs
EPA oon rned about flooding of
the West Camp mines because
disthage m underground. ga
could ther cor n Si r B
Cre& Ground r sampiss from the
Tra ne Sh kx I inthe Camp
sh sl d is te of arsenic and
heavy m EPA bolimree that er
Creek could be af Ie by dire
c echarge of corsaminaid ground water
to Mieax a Gulch, which joins Silver
e Ciw w of Montana Street.
Water guilty in Silver Bow Creek also
could be edveissly afisuid if con.
taminated ground r from the West
Care mine i1dngs e to flow into
the shallow ground water along Silver
Bow C r est
EPA hea prepared this sheet to
dee ’ibe the o ions it Pies studied
soMng p i West Camp flooding
pwt lems , and to deechbe current
preferred plan br the first stage
response . The public is encouraged to
ask qu on oomme and offer su
gsstions regarding all the poss ie
Commer from the pubic are sougnt
b h a a public meeting on Septemt*r
Public Misting
ToBsKs ld
Siptsmber 14
ubu are invited to attend a
messing on September 14, 1988
about the West Camp mine
flooding. The US Envimnmsn
Pn Ncllor Agen wiN discuss its
plUpOiId sokiorwto the flooding
problem, respond to questions
and recave comrne
7 OO p.m., September 14, 1988
P l aCL
Montana Colleg of Mineral
Sc in and chnofog Room
of the Engineering Laboratory
B din West
Pat S B Montana
Mep of Butte Mining Distriet
-------
Silver Bow Creek/Butte Area Site Mining Waste NPL Site Summary Report
Reference 4
Excerpts From Progress Report No.2:
Clark Fork Superfund Sites;
EPA and MDHES; August 1988
-------
Progress Report
Clark Fork Superfund Sites
Southwestern Montana
U.S. Environmental Protection Agency &
Montana Department of Health and Environmental Sciences
ISSUES OF INTEREST
Master Plan Develops Prtorltles
In the cooperative effort to improve the environment in
the Clark Fork River Basin, the U.S. Environmental Protec-
tion Agency (EPA) and the State of Montana have
developed a plan for establishing pnorities for study and
action in the Basin.
EPA arid the State have identified 77 potentiai contamina-
tion problems within the four Superfund sites in the Basin.
Each problem represents part of a larger problem or
response action 1 at a Superfund site. The four sates are
the Mulltown Reservoir site, the Anaconda Smelter site, the
Montana Pole site, and the Silver Bow Creek site. For pur-
poses of study and cleanup, the Butte Addition of the Silver
Bow Creek site i being managed separately from the
downstream portion of the site.
order to manage the large number of complex, inter-
related problems identified within the Clark Fork Superfund
sites, EPA and the Montana Department of Health and En-
vironmental Sciences (MDHES) have consolidated the 77
problem areas into 25 “operabl. units.” These 25 operable
units are subject to change as more information becomes
available. An operable unit is a clearly defined, smaller por-
tion of the overall work to be done at a Superfund sits. Each
operable unit is studied and addressed separately to pro-
vide the most effective cleanup.
EPA and MDHES have been setting pnonties on Super-
fund work to be done throughout the Clark Fork River
Basin. They have developed guidelines for establishing the
order of work, and based on these guidelines, they have
identified high; intermediate, and low priority operable units
within the basin (see Table_1 g ge 3). The guidelines for
setting pnonties should ensure that the most serious or
complex problems are dealt with first.
l $ defined in m l giOiWy E the end ef ml P.... 1 ,....& RiCed pW in bold
lace typs oi’ firs mention
The proposed general guidelines for ranking operable
units are presented below.
High Priority Operable Units:
• May have imminent health exposure (e.g., Waikerville).
• Have threat of imminent environmental damage (e g.,
Warm Springs Ponds).
• Provide information needed for other operable units
(e.g., mine flooding at Berkeley Pit).
Intermedlat Priority Operable Units:
• Have long-term lower level health exposure (e g., Ana-
conda Community Soils).
• Have potential threat of environmental damage (e g..
Silver Bow Creek Area 1).
• Have potential to contaminate other operable units
located downstream, down gradient, or down wind (e g,
Streamsade Tailings).
• Have unusually complex problems requinng in-depth in-
vestigation (e.g.. Smelter Hill).
Low Priority Operable Units:
• Have potential for $ow4evel human health exposure (e g..
agricultural lands).
• Have potential for $aw4ovel environmental damage (e g.,
active mine area).
• Have low present impact but potential for increased
health or environmental damage (e.g., Opportunity
Ponds).
• Have low potential for off-site contamination (e g.,
Arbiter).
I
NOTE: The Clark Fork Progress Report provides a
periodic ovenulew of Superfund activities and important
documents in the study and cleanup of the Clark Fork
River Basin. These Reports include information on
issues of interest, plans and progress at Clark Fork sites,
upcoming meetings ways to obtain further information,
and a glossary of Supetfund terms
Specific questions about these actMtles should be
directed to Bob For at the Montana E P A of fico, X l South
Park, Helena, Montana 59626; phone: (4w) 449-5414;
or contact Janie Stiles, Public Information Officer
Oepartment of Health and Environmental Sciences,
Cogswell Building, Helena, Montana 59620; phone:
444-2821 or 1.8X-648 -8465 (toll4ree in-state).
Public invofvement is an important pail of the Super-
fund pro and is encouraged by Superfund person-
nel. EPA and MOHES encourage residents to offer sug-
gestions for inibnnation to include and issues to cover
in the Progress Reports
—1—
-------
14. 1988 (see b below) and dunng the
public comment — from M.igust 29
through September 28. EPA also en-
courages interested persons to review
the lull study, called an Engineering
Evaluation/Cost Analysis at the inforina-
tion repositories listed at the end of this
fact sheet.
After the public comment period
doses EPA will decide how tO proceed
at the West Camp. The ion chosen will
be cornp ble with long4eftfl Superfund
plans for the Silver Bow Creek/Butte
Area Site.
SITE BACKGROUND
During the period of active mining in
the West Camp. ground water was
pumped out of the mines from the Emma
Shaft to the East Camp, where it was us-
ed in Anariconda Minerals Compan s
water management system. (See map.
page 1) The West Camp mines were
sealed off from the East Camp mines by
watertight bulkheads dunrig the l
1950e.
Pumping of w ater from the West
Camp mines was discontinued in 1965.
Dunng the fail of 1965. ground water
began to flood basementa in the area
south of the Emma and Tra na SMite.
To control this problem. Anaconda
Minerals Company drilled a well down
gradient of the Travona Shaft to intercept
water at an elevation below the area
where basement flooding was occurring.
From 1965 to 1969, water flowed from this
well, known as Relief l 21, into
Missoula Gulch and then into Silver Bow
Creek. Water levels in the Travona Shaft
dropped about 40 feet while water flow-
ed out of Relief Well 21.
The Montana Bureau of Mines and
Geology in Butte has monitored water
levels in the Travona Shalt and Relief
Well 21 since 1982. The 1982 water level
in the Tra na Shaft was almost 300 feet
below the el recorded when the flow
from Relief Ydell 21 stopped in 1969. At
that time, the water level in the Travona
Shaft was appr omatelY 400 feet below
the surface of the ground.
H f’. in 1984 water levels in the
Travona Shalt began rising, and by
Mazth 1988 the depth to water was 193
feet. This rise was apparently due in part
to the rising water levels in the Berlwley
Pct system. Water levels in Relief Well 21
began tO rise in 1987 and reached an
elevabon 50 feet below the surface of the
ground in March 1988 (see Figure 1). Re.
cent monitoring results have indicated
that the rate at which water levels are ris-
ing has stowed. Based on this recent
trend, h EPA has conduded that
IRA V ONA
SHAFT
it is difflc*itto predict when coritamuiaed
mine water might discharge from Relief
Well 21.
EPA became concerned about
flooding in the West Camp mines
because contaminated mine water may
discharge from the mines to Sitver Bow
Creek. The State of Montana recently
upgraded and reclassified Silver Bow
Creek from an “E” stream to an ‘t”
stream to e b s’1 legal basis to improve
the quality of Silver Bow Creek The
change in classification means that the
creek must meet higher water quality
standards ui the future. If flooding were
to occur, water from the West Camp
could introduce arsenic, zinc, copper,
cadmium, lead, and iron in concentra
boris that would violate requiremenis for
the 1” fas flcation.
WHAT RESPONSES ARE
BEING CONSIDERED?
Dunng the study of this problem. EPA
identified and screened potential
responses to the floodIng based cii three
cntena effectiveness. unplementability.
and cost. Alter the screening, six poten-
tial remedies remained:
1. Monltoiing. EPA would monitor
water levels and sample ground
water for dissolved metals at the
Travona and Emma Shafts, within
or near Relief Well 21, arid within a
new shallow well to be drilled near
Missoula Gulch. Row rates on
Silver Bow Creek would also be
monitored. EPA would use the
monitoring data to refine its
estimates of when additional
response actions should be taken.
and to refine the final design of its
second stage altemative
Estimated $37Q 7
2. PumpIng end Treatment of
Ground Water. Ground water
would be withdrawn from a new
beflearRelIetWe I 21
and treated with lime. There may
also be a need to rem e arsenic.
The treated water would be
discharged to Silver Bow Creek
Estimated cost $1,714 0a
aces $ smgIs fi ute caicuI ed tram
veiaia ft*ts S flies 0 m ate
4 .1I,msl a rneivsS.
caou%D SURFACE
RELIEF
WELL ’” ” TRAVO A SHAF1
WATER TAIi,E ELEVATION iN
SILVER SOW CUtE ALLUV 1USI
EAR %4ISSOVI.A GULCH • 5117
=
5650—
5600-
5550.
5500—
5450-
5400.
Figure
IFALL 19 05)
ELEVATiON
WHEN
WELL 21
OPERATED
= 12117 & 311$
4 — WATER ELEVATION IN
RELIIS WELL 21
(312111$ A D 131301$?)
“.Olt. LL,EVATIONS ARE APPROXIMATE
1 Water Levels in Travona Shalt and Relief Well
I
-------
EPA DESCRIBES BUilt ADDITION PROGRESS
The focus at the Butte Addition includes mine flooding
issues related to the Berkeley Pit and the Travona Shaft,
planning for the Remedial Investigation/Feasibility Study
on contaminated soils, and removal actions in Walkerville
and at the Timber Butte Mill. . -
Efforts to Avert Mine Flooding Underway -
EPA and MOHES are concerned about the rising water
in the Berkeley Pit because contaminated mine water may
eventually seep into the shallow ground water or be
discharged via surface drainage to Silver Bow Creek. By
late 1988 or earty 1989. EPA plans to initiate a study regard-
ing the pit and related mine flooding. This study will develop
alternatives for preventing possible flooding and the spread
of contaminated mine water. The public will have an oppor-
tunity to review and comment on the plans pnor to initia-
tion of the study. EPAwill provide information about a public
meeting to local newspapers and radio arid TV stations.
EPA is investigating another potential flooding problem
in an area of Butte known as the “West Camp” near the
Travona Shaft (see map). As the mine water level nses in
this area, the potential for spread of metals into Silver Bow
Creek and the adjacent alluvial ground water increases.
However, data from the Travona and Emma shafts and an
observation well in the area show that dunng the past three
months, the rate of water level rise has slowed significantly.
EPA completed an EngIneerIng Evaluation and Cost
Analysis on the Travona shaft dunng July 198& The
analysis indicated that it would be appropnate for EPA to
continue to monutpr the rising mine water in the area and
be prepared to conduct an Expedited Response Action
if necessary to prevent ooritaimn of the shallow ground
water and Silver Bow Creek. This action would be com-
patible with whatever final long-term remedy is im-
plemented after the more comprehensive study that will
follow The Engineering EvaluatiorilCost Analysis will be
placed in the Butte information repositories listed on page
8. and EPA encourages residents to read and comment on
the report. EPA will hold a public meeting in August on the
proposed Travona action The time arid location of the
meeting will be announced by area newspapers, radio, and
TV stations.
Soils Screening Study helps to sit priorities
In May 1988, EPA and MDHES completed the Butte area
soils screening study that was initiated during the summer
of 1987 The full report is available for review at Butte area
information repositories. In general, the study showed
metals levels to be highest at old mill sites and mine waste
dumps. Residences located near mine wastes tended to
have higher levels of metals than those located on the flats.
or even than those on Butte Hill that are somewhat removed
from old mining operations. EPA has prepared a project
summary of the soils screening study. Interested residents
may obtain a copy by contacting Sara Weinstock. EPA
Remedial Project Managei or Janie Stiles, MDHES Super-
fund Public Information Officer, at the addresses shown on
page 8 of this Progress Report.
Wall rvllle Removal Completed;
Timber Butte EvaluatIon Underway
The two-part Waikerville Removal has been completed.
For one part of the removal, the EPA Emergency Response
Branch (removal team) has completed the Removal Action
begun in WalkeMlle during April 1988. While mercury vapor
did not appear to be a significant problem dunng tests con-
ducted in 198Z more recent tests revealed that some
residences with unexcavated basements in the Walkerville
area did contain mercury vapor. Therefore, the removal
team excavated basements and built new walls in seven
homes where elevated levels of lead and mercury vapor
were found.
The removal team also removed soils containing
elevated levels of metals located at or adjacent to 22
residences. These matenals were removed and stabilized
so they cannot be spread by wind or water erosion back into
residential areas.
For the other part of the removal, the responsible parties,
including Atlantic Richfield Company (ARCO), New Butte
Mining, and the City of Walkervifle, have completed the ma-
jority of their work in removing and regrading several old
dumps. The areas will be reseeded and fenced to protect
and maintain new vegetation and soil cover over the dumps
The removai team has also begun to follow up on results
of the Soils Screening Study that show very high levels of
lead at the Timber Butte Mill. EPA collected air and soil
samples at or near the mill property and is now evaluating
analytical results of the sampling. After all test results have
been evaluated, the removal team may begin work on a
removal action at the mill some time during August.
-6-
-------
Silver Bow Creek/Butte Area Site Mining Waste NFL Site Summary Report
Reference 5
Excerpts From Superfund Program Fact Sheet,
Silver Bow Creek/Butte Area Site;
EPA Region VIII; May 1990
-------
Fact Sheet
Superfund Program
Silver Bow Creek Site
Butte Area, Butte, Montana
INTRODUCTION
The U S Environmental Protec on Agency
(EPA) has completed a Work Plan to assess
problems and develop and evaluate solutions
to environmental and pubbd health issues
related to mine flooding and pit filling at the
Silver Bow Creekl8utte Area Superlund site.
The Work Plan was developed in coogera
non with the Montana Department of Health
and Environmental Sciences (MOHES), It
describes activities that wifi be undertaken
during the REMEDIAL INVESTIGA.
TIONJFEAS 1II ,ITY STUDY (R F$)’ on mine
flooding. EPA has issued a UIS.AT A1.
ORDE and an AOMNSTRATIVE ORDER ON
COH$BIT that regime the POTEITIAuLT
RESPONSIOLE PAITES (PIPe) to conduct
the RVFS.
May 1990
SITE DESCRIPTION
AND BACKGROUND
The Butte area has been mined aknout
continuously since 1880. Over thle 110-yew
period, silver, gold, copper, aE lead and
molybdenum have been mined in about 400
underground mines and siverel open pit
mines. This mining adllvity P resulted in
Soil and water contamjnadon and clàng.s in
the way ground and surface water flow in
and near Butte. In 1985. the S vsr Bow
Creek site, which had been on the Superfund
NATIONAL PRIDSITU LIST since Oecesnbur
1982. was expended to include the Buse
Are a.
The mining companies installed an
extensive pumping system to dewatir the
underground mines and the Berkeley Pit
during adllve m n ng . In the lete 1950s
bulkheads, or barners, were installed
underground to inhibit the flow 01 water
between the mines and pito and thereby
improve the efficiency of pumping
operations. The resulting underground
systems caine to be called the East Camp
and the West Camp. The East Camp is the
area that includes the mine workings
Connected to the Berkeley Pit. The West
Camp mines are located south and west 01
the East Camp.
Water was pumped from the West camp
aria un 1965. With th e end 01 acdvs
mining in 1982, the pumps were turned 011
and the underground mines began to flood.
Once water levele reached the bottom 01 tl e
pit it began to fill. The water levels in the
West Camp are currently fligner than thms
in the East Camp. with water in the Berkeley
Pit lower than the water levels elsewhere in
the area. This causes-water to flow into th
pit (See Figure 2. page 4)
The shady area for the mine flooding
portion of the Butte Area site consisis 0114
square miles and includes the Berkeley Pit.
Yankee DOodle Tailings Ponds, the Montana
Resources Leach Pads, all surface areas
draining to the mine workings, me Weed
Concenv’ator and the East Camp and West
Camp mute workings (see Figure 1 page 2)
EPA is concerned about mine flooding in
the aria because the water is highly acidic
and contens high concennitlons of iron,
manganese, arsenic, lead, cadmium, copper.
zinc and sulfates. It the water continues to
rise in the pit contaminated water may
evenhialy flow into the shallow ground
water and to Silver Bow Creek creating the
potential for significant environmental
impacs and human health problems
The purpom of Superfund work at ‘ri’s s e
is to develop solutions to the c3n:ar’r ’ation
to prevent these problems ‘rom xc rrIng
EPA and the PRPs will develop ce a e ians
to resolve these problems I’ “e Mine
Flooding RUFS.
CONTENTS
The purpose of this fact sheet is to
• Provide background on the Silver
Bow Creek/Butte Area Superlund
site:
• Describe the Mine Flooding Work
Plan and proposed RI and FS tasks;
• Describe the Adminisv tjve Order
on Consent and me Unilateral
Order:
• Describe EVA’s and the State’s
Responsibilities:
• Answer commonly asked ques
nons; and
• Oescnbe how the public can
become informed about the site and
involved in the decision-making
process for selecting a cleanup
plan
Public Meeting To Be
Held May 30, 1990
A formal public meebng will be
held on May 30, 1990. EPA will
receive corrimento on the Work
Plan, the Administiatave Order on.
Consent and the Unilateral Order,
Yni, attendance, questions, and
commen are encouraged. The
mo iii wil be held at
TUe 7:00 p.m.
PLACE.. Montana College of
Mineral Sciences and Techno4oqy
Auditorkatt, Library Building, West’
P it Skeet Butte. Montana.
‘Words shown in SMALL CANTAI.
lett on the tir t mention are delined
in the glossary on page 4
-------
TASKS OF THE REMEDIAL
INVESTIGATION SUMMARIZED
EPA has directed the PRPs tO undsr kS
the toliowing teaks duflng the Rimedial iii.
vestigasorl gordon the RVFS.
• lnflsw CesPil inns,aIse monilor
ssgnillcalfl amoUnte el water . ntoii g is
pit rnflou,sl so that alterTlabYiS to CeA
trol inflow c i be evaluated. It inflows can
be conVollid, VsaislM of tile pit waler
potsnba ’ cm ii hI
• Surface Ws isssl msiliW the
flow and quality of waler ii is Sliver Bow
Creeklflufli Ares at the a,.prilMali isa
hoe where Vialed mine waler disisgs
would sew is cresli. This wil piceils
as date neentiy to determine d
discharges to Silver Bow creek meet stete
w —
• S rf1 IN evakiall U.
is l l ngda t e t ode l emis i saflOl lt i ii
I his to the S i4cate PIt system frem
storm waler ninoft tim uppsr Mlssoute
Gulch. Storm waler entering as Sys
dicale Pit evsntu* reaches the Berkeley
Pit ttirouglt the mine workings. it this flow
is signdlcafl and canbe contolied . test.
merit of the Berkeley Pit waler poten y
could be detsiTed .
• i Oleleibed $ ivesIgslS riview
currenly available date iii relevant
Iiterafln to determine wl*UW water p•
— — sliteted so d solid
wUlI pus contdaales signiflca *y to
mine floodIng. This stidy urli evabnale
whether cley UWTISIS ast prevent waler
s.’ ee ’ rc ’) are *roPulSle 1 W CoIl.
yelling is inflow. C s could extend the
time auailehli to develop Vesiflint aIler•
natives tor’the waler is the pit.
• Asu.1i4 ii T g Bern $ review
a previmna safety svaluadis ii is
Yank’s Doodle T Ilnge Pond D to
dslSfmiIIe s ty vis as cut eat c
amount of waW wuld maisdlele1y mw
vie pit, thereby poIedm mdinc1 tile
amount ii time avaiis4 for action.
• Bedisuk S,e W M• le use
existeig stiette arid instell wells to monitor
waW quality and waler levels is the
bedrock. Resulting date would be used to
develop a critical waW acoan level a id to
monitor whether waW Ievel$ ri ’ s more
quickty than anticipated.
RI/FS WORK PLAI’
DESCRIPTION
The Butte Miss Flooding RIIFS Work P’s:
describes how the involved parties dl cci
lect the necessary information to assess
human health arid environmental roØien
associated with mine flooding ard deveic
SOlutionS tO the problems identified. This .r
formation must be garnered in crcer
understand what is haooemnq now and
develop tile most appropnate solutions. Suc
information will also help document ana sig
port the remedial action taken .n fle ever
that litigation becomes necessary. The qI/F
is scheduled so REMEOIAL DESI .
/flEM(OSAL ACTiON (RWflA) can start y
Fall of 1993. ThIS allows time to actuai’
design and construct a treamient iant :
tate 1996 ii it is necessary.
The general obpicbves of the AI/FS are
identify the nature and extent of contamin
dori associated with mine flooding r
evaluate remedial alternatives. The specif
gools of the remedial response for thiS w
are to mitigate the impact of mine at
discPwge on Silver Bow Creek a the aoi
cent ALLUViAL aquifer and to maintain tic
toward the pit and thereby contain tne cc
taminaled bedrock ground water n
Berkeley Pit for ultimate treatment Spec’:
remedial response ob ectives to meet :r.e
goals are to control the rate of mine tIOOCi
and to design and implement an aopropn
remedy to ensure that discharges at mi
waler to Silver Bow Creek or tne adlace
alluvial aquifer meet applicable state a
federal waw quality standards.
• Leasi Pill Ales ABevial Investigatiee:
s monitoring wells tO evaluate whe
me leach peds are a current sourci
conlanhoaboli to the alluvial ground w
system and Silver Bow Creek.
• P1W tend le uWy centify
p01 monitor all existing pnvale
mwh al shallow wells to yovide a
hois usloimabon on alluvial water Is
aid waler —.
• NS.S1 JitiS — es sI ’ s sample
waler aid conduct studies to deterr
the f i 1 ty of nsutiulizrnq me pit *
by dlspeaing ii mine tansncs n me p
it die null fm yeaml.nT s ; stDorec
indicated in some of ‘e i•s aoove)
novative tieUnent tecr: .s nigh
developed will reat e a:er
complem and sthcient v
i s a iUr E
C
-------
ADMINISTRATIVE ORDER
ON CONSENT AND
UNILATERAL ORDER
EPA has issued an Administrative Order on
Consent and a Unilateral Order. These
documents outline me work to be conducted
during the RUFS. ‘he Schedule for me woric.
and me arves esoonsiOIe for eacn portion
of the work. These legal documents direct
me PRPs to conduct tne iork accoraing to
tne work alan Hith EPA and MOHES over
sight.
The Unilateral Order governs actions by
me Tollowing cornoanies: New Butte Mining
Inc.. Central Butte Mining. Inc.: North Butte
Mining. Inc.; Tzarina.Travona Mining Cor-
oraDon: Mountain Con Mining Company;
West Butte Metals. Inc.; Blue Bird Mining
Company: Eureka Mining Company; Yankee
Mining Company: East Ridge Mining Corn.
pany. and Black Rock Mining Company.
These companies are to compiete me foNow-
1 ng tasks, which ate descnbed on page 2 of
this Fact Sheet.
• Pnvate Wee Inventory
• Butte Disturbed Soils
• Bedrock Ground Water Monitoring
• Syndicate Pit Evaluation
INFORMATION CENTERS
EPA and MOHES hive estaoutsnea
files where residents can review documeq
related to me Butte Ar Su erfunø wo,
The Work Plan for me me
ministrative Order on Consent, and
Unilateral Order for Mine Floooing mo
documents can be fOund ifl these eacii
files, The locations are listed below
Butte EPA Office
Silver Bow County Courthouse
1 55 West Granite Street
Butte, MT 59701
(406) 7824452
Monday.Friday 8:00 a.m. 5 00 n.
U.S. Environmental Protection agency
Federal Buiiding, 301 South Paric
Helena, MT 59626
(406) 449.5414
8:00 a.m. 5:00 p.m.
Butte Silver Bow Library
106 West Broadway
Butte, MT 59701
(406) 7231262
Tuesday 12:00 p.m. 9:00 p.m.
Widesaday 9:00 a.m. 9:00 n.m.
Thursday-Saturday 9 am. - 6.00 p.m.
Clesed Sunday & Monday
Figure 2 illustrates the onsilip of ground water beneath the Butte Area to the Berkelsy PIt and me 5.410-foot criticai •..
datum). Relative waterievels are shown to indicate the separation of the.East Camp and the West Camp. Thu data used for wa
figure are from the Montaiw8&areau of Mines and Geology (MGMG).
SGS
The AOm.nisuative Order on Consent
governs actions by me i oNowuig companies
and ndividua Atlantic Richfield Company
(ARCO). Mr. Dennis Wasltinglon, Montana
Resources. Inc., AR Montana Corporation,
ASARCO. Inc.. and Montana Resources. AM
tasks and work outfined in me Rl/F$ except
those specific tasks listed immediately atiove
ate to be Completed by these companies. In
addition, the Administrative Order requires
the PRPs to maintain the water elevation in
the 8erkeley Pit below 5.410 feet (USGS
datum).
WHAT ARE EPA’S AND THE
STATE’S RESPONSIBILITIES?
EPA. MOHES. and the PRPs each have par-
ticular responsibilities related to this RI/FS.
The PRP responsibilities are spelled out in
the section on mu Administrative Order on
Consent and th Unilateral Order. EPA has
the agency lead on all Butte Superfund ac
tivitles, working with the State.
EPA and the Stats w :
1. Oversee the RVFS;
2. Identity appropriate requirements
(dischurgs standards, sludge dispooal
standards, ito).
3. Conduct a U$K A$$ESSM8IT : and
4. Select lbs final mmed .
Conceptual Model of Water Levels Below the Surface
Butte
Travons
Montana College of Mineral
Science & Technology Library
West Park Street
Butts. MI 59701
Monday .
8:00 a.m. . 10:00 p.m.
Friday 8:00 a.m. 5:00 p.m.
Saturday 9:00 a.m. . 5:00 o.m.
Sunday 1:00 p.m. . 10:00 p.m.
I
*
Mns
I
w _ r loved
k 5lT1nS
Ground w r Bow
V Ground wa r loved * MBMG d
Silver Bow Creek Superfund Site
Butte, Montana
-------
0. Why is EPA so concerned about the
water in the Berkeley Pit?
A 1 tue water in the pit and associated
mines is released, it Could further con.
aminate the ground water and surface
mater The water fl the Dit and mines
contains high levels of arsenic Cacimum.
lead. cooper, zinc, iron, manganese and
sulfates These substanCeS have proven
adverse ettects on me environment.
human health and aquatic life
0. WIly 1 5 the pit water level such an issue?
A As long as the water level in the pit re
mains below a critical level all excess
water in the mine workings will continue
to flow into the pit. The cnucal level is
based on extensive monitonng of water
levels in both the alluvial and bedrock
ground water systems by the Montana
8ureau of Mines and Geology (MBMG)
and me Montana Department 01 Health
and Environmental Sciences (MOHES).
This level is the lowest alluvial ground
water elevatIon in the area.
Once the water in the pit exceeds this
elevation, the potential exists for water to
flow away from the pit into the shallow
ground water Without action to control
the water level in thO pit. the pit water
would Contaminate the ground water.
Eventually this contaminated ground
water would reach Silver Bow Creek and
contaminate the stream. MBMG monitor-
ing has revealed that the water ui the pit
rose 30 feet in 1989 MBMG records also
show that the rate of rise Ms decreased
each year. This provides ample ome to
complete tne R IIFS and implement a per-
manent solution.
The PRPs who signed the Adinininvadve
Order on Consent have agreed not to
allow the water in the ENSIGTIP S istSin
to exceed the 5.410 lest (USGS data)
level. If the water doss ei’csed Vex level,
they are sub Sct to $25000-per-day
stipulated penalbsS.
a. wth ss Ithei i
—7
A. Under the Comprehensive Envwoiimsn
Response, Colupensabon, and Lia bil ity
Act (CERCLA) of 1980. also known as
Supertund. the costs are paid by Vie
P Ps. EPA lies issued an AdmiflisVaVvS
Order on Consent and a Unilateral Order
that outhne each company’s responsabdi.
ty for the mine flooding work. i.e.. who
will complete and pay for each W I of the
w .
0. Can the metals in the water be recovered
and sole to help oftiel the cuts of the
cleanup?
A The Mine Flooding FS will evaluate this
alternative Currently, the technologies
that exist to recover the metals may be
too expensive to make metal recovery
cost ettective Some of the costs to be
considered are construction, operation.
and maintenance of a facihty Other fac
tot’s that must be evaluated in relation to
these costs are: reduction in sludge
volumes, reduction of sludge toxicity.
ability to meet water discharge standards
and value Of recovered metaJs.
0. When w a treatment facaty be built?
A The RIIFS is expected to be completed by
the fall of 1993 This schedule allows
time to design and construct a trealiTlent
plant by late 1996 if necessary.
However, current information indicates
that a much later construction date is ap
propnate. A final date for construction
will be dictated by the Record of Decision
(ROD) after completion of the AIIFS.
Pnmary factors involved in this decision
will be final cnncal water levels, the long-
term rate of pit tilhng and the inflow con-
tainment measures taken to slow mine
flooding.
0. Why 4. the I4h take a lug?
A. The 11 O.year history of mining in this
area has left high levels of contamination
in the sod and the water Throughout the
Clark Forth River Basin. The magnitude of
the problems and the volumes of the
wastes require extensive evaluadon in
order to achieve solutions that are effec-
tive. implementable . and compadhi *1111
other remedies the Basin. Superlund is
an enforcement program, in which those
who contaminate the environment are re-
quoed by law to pay for tile cleanup. In
order to enforce this the study data must
hole up to cowl scrutiny. The data must
also meet quality assurance and quakty
control requirements and EPA regulations
and guleancL
GLOSSARY
A number of technical terms are usec
Superlund wont; those used fl ‘fliS
sheet are defined below
Administrative Order on Consent:
negotiated legal document issued by E
and signed by PAPs directing an rCi’ ’Ci
business, or other entity to taxe c rrec-
action or refrain from an activity cesc’:
the actions to be taken iiolauicns
penalties for failure to comoly t’ic can
enforced in court
Afluvwm materials cepos teo by a srea
generally composea of sand cay cr ;a
Aluviel refers to sucn lcrmauions
Aquifer A porous uncergrour.c .
tion composed of materials s c as a
sandstone, or lH’nestone iral can s::re
transmit ground water to i eils s r rgs
creeks.
BedrocL generally unbroken Scud
overlaid in most places by Soil r
fragments.
Grosud Water The Supply of ‘resn a
tound beneath the earth s surface -
tnstitutisnal Controls: laws nicrt are cast
by local governments that govern ac-ion ‘r
can be taken at hazardous saste st
These would include zoning ‘eguiatioi
waste disposal regulations etc
National Ptiontlss List (NP 14 EPa of
most senous unControlled or aoancor
hazaj’dous waste sites identified 1 or ooss.
long-term remedial action under Supertu
A Site must be on the NPt. to receive ‘riot’
from the Superfund Trust Fund
Potutlaly Respensales Parties tPRP*
dividuals or companies such as owne
operators, transporters. or Maste enerat
potentially responsible for or contributing
contamination problems at a Superfund S
Whenever possible. EPA reQuires PR
ough administrative and legal actions.
clean up hazardous waste sites
Na Il Adsu The actual construction
implementation phase of a Sucertund
cleanup that follows remecial Ce sign
Rerr’ Design: A phase of remedial ac
that follows the RIIFS and includes devel
meAt of engineering drawings and specifi
lions for a site cleanup.
Re..dlal tuestlqatlenlFeasibillty Sti
(Rli $ a two-pan study to betermine
nature and extent at contamination and w.
to solve the problems created by thiS C
taminatiofl. During the RI sc entists den
the types. locations, anc 3r ”Ouflts Of C
tanunation and the riskS triey av cresefi
human health and tile en r:r’e t Jur
the FS scientists and ‘ç - ‘s Cevel
screen, and evaluate a S ‘ n u
contamination.
ANSWERS TO COMMONLY ASKED QUESTIONS
As Supertund work proCeedS in the Butte area, residents ask EPA a number of questions. The
lollowing are some of the most comrgOflty asked questions, and EPA’s responses.
a
-------
Silver Bow Creek/Butte Area Site Mining Waste NPL Site Summary Report
Reference 6
Excerpts From Superfund Program Fact Sheet,
Silver Bow Creek Site, Butte Area;
EPA Region VIII (Montana Office); May 1990
-------
Fact Sheet
Superfund Program
Silver Bow Creek Site
Butte Area, Butte, Montana
May 1990
INTRODUCTiON
The U.S. Ervwonmental Protecdon Agency (EPA) ii oooperaxn e Montana Depat nent of Heaidi and Enwonmentaj Sc*nces (MD ES) as
pletad a plan to elimirtato or isotato a number of souros arm øta may P OSe PO flbaI fiske to l’iuman healdi at die St er Bow Cteei Butte Area s :i
Bufle. Montana. Woekwil be i tnJirie 1990 and sl concen on mine stes mps loca d nearresidentaj areas or ainages leading into ouoic are
Ths work is part of a larger overall etfort to c an t Butto area nei ’tborfloods ø I have beeii contaitmaxed by rmrvng wastes. The deanup Of $cur ar
is neOSssary before acoon is maad on resiUern l Propeflies bemuse sour areas petendally cotid recontaminate properdes pre iousJy aCores
DESCRIPTION OF AREA
The area idenelted acdon contains ste mate 1al from former mnng
milling, and sine teroperadons in popuated areas of Bu Waikandis,
Montana. The lends from the Nordi WaJisMWssoiMGti ,area
to the Berkeley Pit and soum to Silver Bow Creeli.
The cioes of Bu and WaMrWl, have been dMded into six general work
areas.
WALXERVfl.LE. (PriorIty Soil Area 4)
Rising Star
Moose Dump Damage DtotI
Adar ide
CorTa I I
Movie Cans
Sister
Rock ls id
WE$1 DE BUTTEIWALXERVIUL ( Pilorty Sod Mm 8,27)
Eveline Dump
Railroad bed soi, area we of Montana Tide
SOUTHCENTRAL BUTTE: ( PrIority Sod Ms 29)
Tenaon 4eansy
Green Cooper- CtidUwuId
C 4TRAl. BUTTE: ( Priority Sodpifies 31)
BA&P Railroad backs between P. y id lal Mør ni S1mst.
SOUThWEST BUTTE: (Priority Sods Ms 28,32)
Travone $oiát Tra ne
Star Weet Waaitos Sampl ig
UPTOWN BUTTE: (Priority Sods Mea 5,9, 18, 20)
Jasper Steward P Ins Ys
West Stewerd Pailang Lot Man i Pit
Waste Dump Northwest of Old osy
the Moun tainCon I I Riafto
T? i dcofN b ecom p l Fdof1 0w l1 i N
emainingwortto be shed by d i i FaM of 1991.
TP ou iana eementwi EPA and MOMES, the Potendally Res
sibli Pardis (PRP) eu be responsible ior me work and for ture
tertan . EPA w provide cormious oversi it to assure stat w r
completed prope ty and on sthitis.
E i Is sv js, therefore the ac on taken at ea a
eli be peoIcfo Ntvsa. Msome b bons the work eu com ne sev
a ons. in general, however . the wart eu fad inc the following categor
• To r.mavl—4fl waste wil be removed aruo taken to ore c i
Ji lw areas.
• Pitaf rumovaf—gert of die wastes *11 be removed and ken
dspo l area. The remasang material euU be tecontoureo
amsiw rapped , revegutated and nced where necessary
INFORMATION FAIR
TO BE HELD MAY 21,1990
You we iMted to a n N ma i Faa ’ to earn more at
Si uitmd sort on contaml 1 .id sods in flto and WaJkeMle. The E
$*to sthudwo r tandrecervepu.
nimwL Yaw aasI ni. , as8ons, and comments are encourage
7 0 m.
PL E: Copper Kng Convundon Centw
HarrIson Avemis, Bus. Montana
The lnfonnallon Fir saVe depteys and ad bonaJ flfotTT?a or
remi plans, ar how thu proposed wait affects nearby drainaç
va iote and reaJsndafsstengsw nthsCdesof Butti anc Walkerv
EPA pereomuf e be avallibis to ad su yota’ comments arid conce
ANSWERS TO
COMMONLY ASKED QUESTiONS
As $i srft%uf wait pr oeeds Ii N B area residents ask the EP
ruii er of aedorie. Fodowrg ii some of N most commonty as
qIJM11One and EPA’s rsapwiais .
0. 1%?it of cwitemtiai*jn age pearl in the soil’
A. Resits from sod semping ai cate mere may be elevated ‘eve
one or mare of die blowing metals . lead, arsenic, spper, oac
and mer sy.
GOALS —
The wait is designed to remove or stan” miimg waits matuitato in
orto
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Silver Bow Creek/Butte Area Site Mining Waste NPL Site Summary Report
Reference 7
Excerpts From Clark Fork Superfund Sites: Master Plan;
EPA and MDJIES; November 1990
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Bütte Area
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area Further, EPA is overseeing an engineering evalua-
tion and cost analysis for Lower Area One, which In-
cludes the Colorado Tailings, the Butte Reduction
Works, and the manganese stock piles.
Initial work has begun on the Priority Soils expedited
response action, which will focus on lower level con-
tamination in residential yards.
The operable units and related contamination issues
are listed below Operable units are identified in bold
face at the left margin, removals are underlined
Butte Area
Priority Soils
Human health risks associated with exposure to
soils contaminated with lead, cadmium, arsenic,
and mercury from mining waste
Wal kervi lie—Removal completed In 1988
• Human health risks associated with exposure to
soils Contaminated with lead and mercury from
mining waste.
• Remedy: approximately 300,000 cubic
yards of contaminated soils were removed
Timber Butte—Removal completed in 1989
• Human health risks associated with exposure to
soils contaminated primarily with lead and
arsenic.
• Remedy approximately 40,000 cubic yards
of contaminated soils were removed.
Other Priority Waste Sources—Removal underway
in 1990, anticipated to be completed in 1991
• Human health risks associated with exposure to
soils contaminated with lead and arsenic from
mining waste.
• Remedy: contaminated soils will be re-
moved in 1990 and 1991.
Residential Soils—all identified residences not
previously addressed under the other actions.
Mine Flooding (Berkeley Pit)
• Underground mine workings and Berkeley Pit
flooding and generating of acid mine waters.
• Potential for discharge of acid mine water to SilverS
Bow Creek.
• Contamination of ground water.
• Potential impacts to wildlife.
Travona—Removal implemented in 1989
• Flooded underground mine workings
• Potential for discharge of mine water to Silver
Bow Creek.
• Contamination of ground water and potential
drinking and irrigation water sources.
• Potential impacts to wildlife.
• Remedy: More than 60,000,000 gallons of
mine water treated and discharged so far
Butte Non-Priority Soils
• Potential exposure of future human populations to
contaminated soils in non-residential areas
Butte Active Mine Area
• Source areas of fugitive dust contaminated with
heavy metals.
• Source areas of acid mine drainage discharge to the
Berkeley Pit.
• impacts to wildlife resources resulting from
exposure to mining waste
• Potential exposure of future human populations to
contaminated soils
Silver Bow Creek
(Original Portion)
Lower Area One (including Colorado Tailings, Butte
Reduction Works, and manganese stock piles)
• Surface soils and sediments, surface water, and
ground water contaminated by mine and mill tailings
and acid mine water discharges. High levels of
heavy metal contamination.
• Contamination of potential drinking water supplies.
• Potential exposure of future human populations tO
contaminated soils and/or tailings.
—36—
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Streamside Tailings
• Extensive deposits of mine tailings and sediments
contaminated with heavy metals.
• Potential contamination of irrigation and drinking
water supplies.
• Potential exposure of future human populations to
contaminated soils and/or tailings
Rocker
• Soils contaminated with arsenic and potential
organic contamination as a result of past timber
treating activities
• Potential for contamination of ground water and sur-
face water.
• Potential human health risks associated with ex-
posure to contaminated soil and ground water.
• Remedy 1,021 cubic yards of arsenic-contami-
nated soils and wood chips were removed in
1989
Warm Springs Ponds
• Contaminated surface water, soils, pond bottom
sediments, and ground water associated with treat-
ment ponds that capture mining waste from
upstream sources.
• Potential for release of contaminated water and
sediments due to instability of pond dikes during a
flood or earthquake.
• Impacts to wildlife.
• Potential contamination of irrigation and drinking
water supplies.
• Potential exposure of future human populations to
contaminated soils and/or tailings.
Mill-Willow Bypass—Removal begun July 1990
Remedy. 210,000 cubic yards of tailings and
contaminated soils will be removed from the
Mill-Willow Bypass and placed in the dry
area of Pond 3 by November 1990. The
north-south pond berms will be raised and
strengthened to withstand a maximum
credible earthquake and 0.5 probable max-
imum flood. The removal will be completed
by December 1990.
MONTANA POLE SITE
The Montana Pole site is located in Butte at 202 West
Greenwood Avenue. It is 40 acres in size and lies at the
southwest edge of the city on the banks of Silver Bow
Creek From 1947 to 1984, the Montana Pole Treating
Company used the site as the location of its wood
treating operation. Montana Pole commonly used
organic compounds including pentachiorophenol
(PCP) and creosote in its operations. In 1983, EPA deter-
mined that wastes were seeping from the site to Silver
Bow Creek at the rate of two to five gallons per day. In
addition, EPA found that on-site soils and ground water
had been contaminated by these wastes. These prob-
lems were addressed in a removal action initiated in
1985 while the site was still part of the Silver Bow Creek
site. The Montana Pole site became a separate Super-
fund site in November 1986. Specific problem areas at
the Montana Pole site are summarized below
• Pole treatment activities have resulted in high levels
of organic contamination in soils and ground water:
• Human health risks associated with exposure to
contaminated soil, ground water, and surface water;
• Source of PCP and other organic contamination in
ground water and in Silver Bow Creek; and
• Impacts on water and land wildlife.
Montana Pole—Removal completed in 1987
Remedy. 10,000 gallons of contaminated
ground water were treated: 12,000 cubic
yards of contaminated soils were removed.
In June 1990, MOHES began oversight of a remedial
investigation and feasibility study of the Montana Pole
site. This will determine the extent of contamination, the
effects upon human health and the environment, and
the appropriate cleanup alternatives. Contaminant
studies associated with the Montana Pole site will be
conducted downstream to the lower end of the Colorado
Tailings. The streamside tailings remedial investigation
will determine if Montana Pole contaminants have
extended further downstream and if they need to be
remediated. ARGO will perform the site investigations
under MDHES’s supervision.
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Silver Bow CreekfButte Area Site Mining Waste NPL Site Summary Report
Reference 8
Excerpts From Site History of Smelter Hill -
Anaconda Smelter NPL Site; Prepared by GCM Services Inc.
For ARCO Coal Company; June 1989
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3
increasing daily production of 99.97 percent pure copper to 120 tons. putting Daly and the
Anaconda Mining Company on equal footing with Michigan copper producers. Additional
improvements were made to the Upper Works in 1894. Daly arranged to have the reverberatory
furnaces enlarged, increasing daily production and efficiency. By increasing the length of the
reverberatories Daly’s engineers doubled daily output while maintaining the same fuel consumption.
The Lower Works used three masonry flues and smokestacks the size of those at the Upper Works.
Yearly production at the Upper and Lower Works (130 million ibs) far outdistanced all the
competition in Butte and Great Fails (Boston & Montana, 54 million Ibs) by 1901 but Daly’s
acquisition of other highly productive Butte mines prompted the need for further expansion at
Anaconda. Daly’s chief problem in his location north of Warm Springs Creek was space for
expansion which he solved in 1902 by moving operations south across the valley. Demolition of
the Old Works (Upper and Lower) began in 1903, shortly after the startup of the Washoe Reduction
Works, with the removal of all equipment wood and steel, leaving only stone and brick ruins after
1906. (Quivik 1984).
Creation of a Mining and Metallurgical Empire: The Anaconda Copper Mining Co.
By the lame 1890s Marcus Daly’s conso1i tion of mining interests in Butte led to a shortage of
smelter capacity in Anaconda. In addition, Daly’s vision for the future had outsuipped his personal
financial means. Daly’s dilemma ar acmcd the attention of William Rockefeller and Henry It
Rogers of Standard Oil and in 1899 they formed the Amalgamated Copper Company, which
absorbed Daly’s Anaconda Copper Mining Company. Daly traded his conn oUing shares in the
Anaconda Copper Mining Company for shares in the new copper trust, and as president of
Amalgamated, Daly had the assets needed to build the reduction works of his dreams as well as to
create America’s first fully integrated copper company, with control of all aspects of production
from mine to smelter to refinery to fabrication. Daly hired Frank Kieperko, designer of the stare-of-
the-art Boston & Montana smelter and refinery in Great Falls, to build one of the most efficient and
adaptable mineral processing plants in the world. The Washoe Reduction Works began operating in
1902, two years after Daly’s death, at a capacity of 4800 tons daily. Klepezko designed the Washoc
smelter so that each department could grow and expand with demand : by 1908 production capacity
grew to 12,000 tons of ore daily, producing 600,000 lbs of copper and 9000 tons of slag and
r2ilings and by 1933 the Washoe smelter produced 1,000,000 lbs daily. The legacy of Daly’s
vision did not end with construction of the world’s largest non-ferrous mineral processing plant.
Daly’s successor, John D. Ryan, continued to add to the ACM Co. portfolio by acquiring additional
smelting capacity in Great Falls, Monrana Toocle, Utah; mining operations in Arizona and Chile;
expanded refining capacity in Great Falls and New Jersey and the purchase of a fabricator in the
American Brass Company. Facilities at the Washoc Works expanded into more complete use of the
Butte ore with ilie addition of zinc and manganese plants. ACM Co. interests also included coal,
timber and an ore-hauling railroad, the Butte, Anaconda & Pacific. By the end of World War I the
ACM Co. represented the most powerful economic and political force in Montana and one of the
world’s largest producers of base metals (ACM Co. Collection, Tn-County Historical Society,
Boxes 8; 59; 60).
HISTORICAL DEVELOPMENT OF THE WASHOE REDUCTION WORKS
When completed in 1902 the Washoc Reduction Works constituted an industrial processing plant
of extraordinary magnitude, covering over 230 acres with a monthly copper production of 12
millign lbs. Expanding to meet the demand created by increasing Butte mines production, the
Washoe eventually expanded to 25 million lbs monthly with a workforce of 2800. To meet the
17,000 ton per day production capacity the Wasboe consumed 750 tons of Diamnondville,
Wyoming bituminous coal (12-15 percent ash), 2500 tons of lime (for flux), 778,000 kilowatt
hours of electricity and 60 million gallons of water (75 percent reclaimed in process) transported
through eight miles of wooden flume. The following is a detailed description of the on-site
I )
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Silver Bow Creek/Butte Area Site Mining Waste NFL Site Summary Report
Reference 9
Excerpts From Feasibility Study For
the Warm Springs Ponds Operable Unit, Volume I, Draft;
MDHES and CH2M Hill; October 1989
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1. SILVER BOW CREEK
INVESTIGATION
Feasibility Study
for the
Warm Springs Ponds
Operable Unit
Montana Department
of
Health and Environmental Sciences
( S)
Prepared by
•. 1 DRA T
Volume I Report
H2M HII
October 1989
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CUTLVE S fLRT
The War5 Springs Ponds are a part of the Silver Bow Creek
Superfund Site. The ponds ar. located at the downstream end
of Silver Bow Creek, just above the cortfluenc. of the Mill-
Willow Bypass and Warn Springs Creek. That confluenc. is
the defined beginning point of the Clark Pork iver.
Pigurs ES-i shows the major features of th.-Wtn Springs
Ponds Operable Unit and establishes the bóqs Iac ies of the
study area.
The Clark Pork Basin, which include thà Silver Bow Creek
Site, is the largest geograpl nation being
addressed under Supsrfund. en impacted by
over 100 years of mining one in the
Butte and Anaconda an with th . discovery
of geld in 1864 on . By 1884, the Butte
area contained ove ‘copper and silver mines,
9 silver mines, . Minittg and smelting contin-
ued until 1982 4naconda Minerals Company, by that
tins owned by -Richfield Company, closed the
Berkeley Pit in Buvbsy $(ning and milling has since
resumed, with the takeover of operations by Montana
Resources, Inc., and others in 1986.
Over th.—years, the ffiining and related activities have
resulted in extensive soil, water, and air conta {nation
within tbe study area. Cont2ffi4nstion of Silver Bow Creek
occurred from th. outset of 1 4-fiing activities. Mining,
milling, and smelting wastes were dumped directly into
ES-i
“vy
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Silver Bow Creek and transported downstream to the Clark
Pork River.
In 1911, the Anaconda Copper Mining Company built its first
treatment pond near Warm Springs, Montana, to settle out
wastes from Silver Bow Creek before the watsr reached the
Clark Fork River. This is now noted as Warm Springs Pond 1
(see Figure ES-i). Warm Springs Ponds 2 and 3 were
constructed in approximately 191.6 and 1959, respectively, as
additional settling capacity was needed. The .ponds now
cover an area of approximately 4 square mili/ Over the
past 80 years, an estimated 1.9 million cub 4.j rds of
tailings and heavy metal cont { .atsd s mstits (sludges)
have coliseted in th. ponds. The 13 million cubii yards of
wastes could cover the playing ar.a .rai football fields
90 feet deep, which is as building.
Mining wastes are no longe el k.d,fr1ic ectly into Silver
Bow Creek, but tailings4e s t$\*1 )Ug th. creek banks
continua to erode and rs ,sii creek during periods
of above-average f]h vJ P4 - lo . It is estimated that
approximately 3 .1!! min’ci bj yards of contamii,ated tailings
are still pres t\along\ th.e banks of Silver Bow Creek.
Through dissolut th&-tailinge and sediments cause the
water flowing in Si .t Bow Creek to be cont inated
with dissolved metals, particularly copper and zinc. Other
metals detscted in Silver Bow Creek are arsenic, cadmium,
lead, iron, al i (t um, and manganese.
The Warm Springs Ponds ar. still used to contain entrained
sediments and treat the contsi inated water flowing down
Silver Bow Creek before it reaches the Clark Pork River.
Th. ponds operate by settling out tailings particles and
other solids and by reducing the concentrations of the
ES-2
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Silver Bow Creek/Butte Area Site Mining Waste NPL Site Summary Report
Reference 10
Excerpts From Proposed Plan: Warm Springs Ponds;
EPA and MDHES; October 1989
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October 1989.
Warm Springs Ponds
Proposed Plan
Silver Bow Creek Superfund Site Report
By Montana Department of Health and Environmental Sciences
and the U S. Environmental Protection Agency
Introduction
The Montana Department of Health and Environmental
Sciences (MDHES) and the U S Environmental Protection
Agency (EPA) are seeking comments from the public on the
Warm Springs Ponds Feasibility Study and this Proposed Plan
to ensure that the remedies selected will meet the needs of the
interested public. The Warm Springs Ponds are one of five
operable units identified for the Silver Bow Creek Superfund
Site The public comment period extends from October26 to
December 29, 1989.
Sections 1 l3(k)(2)(B) and 117(a)oftheComprehensive
Environmental Response. Compensauon, and Liability Act
(hereafter “CERCLA”). as amended by the Superfund Amend-
ments and Reauthorization Act (SARA), requires the lead
agency to issue a proposed plan of remediation (cleanup) for
any site addressed under CERCLA and to make the plan
available to the public for review and comment. This Proposed
Plan fulfills that requirement. The plan discusses alternauves
for conuoUing contaminauon associated with groundwater,
surface water, pond bottom sediments, tailings and containi-
nated soils within the boundaries of the Warm Springs Ponds
operable unit. The plan presents the cleanup alternative pre-
ferred by MDHES (the lead agency) and EPA (the support
agency); and the rationale foridenufying thealcernanve. Italso
provides background information on the site, summarizes site
risks and the results of emedial Investigation, describes
cleanup alternatives evaluated for the site, and outlines the
public’s role in the final selection of a remedy. The preferred
cleanup alternauve identlfied isaprelmunary selection and will
be made final in the Record of Decision (ROD) after MDHES
and EPA have considered the public’s comments and any new,
significant information received during the comment period.
The Preferred Alternative is based on the Adminisuauve Rec-
ord that has been dcveloped. the remedial invesugauon reports
which characterize the site and discuss the nature and extent of
cornazninauon, and the feasibility study, which describes how
the vanoujs remedial alternatives were developed and evalu-
ated.
WFffiS emphasizes that comments arc being solicited
on all of the alternatives presented in the feasibility stuth and
in this Proposed Plan, not the Preferred Alternative alone The
remedy ultimately selected for the operable unit may be the
Preferred Alternative, a modification of it. a combinauon of
elements from sortie or all of the alternatives, another response -
action based on new and significant information, or public
comments.
Detailed information concerning any of the material
included in the Proposed Plan may be found in the remedial
investigation and feasibility study reports. These reports ha’. e
been placed, as have earlier reports , ax information repositories
The locations of these repositories are listed on page 16 of this
plan.
Additional documentation regarding remedy selection
is available in the Adminisnacive Record for the site The
administrative record has been pLaced at three locations, also
listed on page 16 of this plan.
u sfr Adwa,u zsv. Record LI a owha. of a re,,igd aI .ic wit
p eii for the Por4, beiq ‘op ed by :fr AiL ,itic Richfield Cov tpaity
(ARCO) ARCOis i 4 ified rup ib1e pony for the Won,t Spn*g:
P o r4,.
Contents -
Ponds background
Warm Springs Ponds map
Siteriska 4
Public rneatlnp 4
Cleanup Objectives S
Cleanup alternathes 6
Publ lccomment 11
SilBowCreeksitemap 11
Evaluation of alternatives... 12
Summ*ry of Preferred Alternative IS
Gto arT’ - 15
Where to fInd site documents 16
.1
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Ponds have a long history
SITE LOCATION
The Warm Springs Ponds operable unit is one of five
operable units idenufied for the Silver Bow Creek Superfund
Site. The S Rer Bow Creek Site is one of four dist inct but
conuguous Superfund sites in the Upper Clark Fork Basin area
of Montana. The Silver Bow Creek Site begins in Butte and
extends approximately 145 river miles to the Militown Reser-
voir juSt east of Missoula.
The Warm Springs Ponds are located within Deer Lodge
County. about 27 river miles northwest of Butte, at the end of
Silver Bow Creek.jusrabove theconfluenceof the Mill-Willow
Bypass and Warm Springs Creek. The confluence of the Mill-
Willow Bypass and Warm Springs Creek is the beginning of the
Clark Fork River. The unincorporated town of Opponunity lies
at the southern-most edge of the site, west of U.S. Interstate 90
(1-90). The unincorporated town of Warm Springs is at the
northern boundary, adjacent to Pond I on the west side of 1-90.
The only incorporated town within the county is Anaconda. ap-
proximately six miles west of the site along Highway 48.
The boundaries of the Warm Springs Ponds operable
unit are depicted in the figure. The site extends from the
intersection of Silver Bow Creek and 1-90 upstream of Pond 3
at the south, to the confluence of the Mill-Willow Bypass with
Warm Springs Creek at the north. The western boundary is
slightly west of the Mill-Willow Bypass (although east of 1-90)
and the eastern boundary is the interface between marsh vege-
tation and the foot hills on the eastern edge of the ponds. The
site covers approximately 2.500 acres. Its major features
include three settling ponds. a series of wildlife ponds. and the
Mill-Willow Bypass.
SITE HISTORY
From the beginning of ore COOCCZICStinWSmC Isin8 ac-
uvitiesin l88Ountil l9ll,mining,Mil1ing,andflg 1S1
from the Butte and Anaconda areas were dumped directly into
Silver Bow Creek and were transported down seam to the
Clark Fork River, at least as far as Milliown Reservoir. some
145 river miles. Although mining wastes areno longerrdewd
directly into Silver Bow Creek, poruons of an estimated tiwee
million cubic yards of tailingsremain deposited along the creek
banks where they ar 1bjeCt to erosion aid movement clown
the creek during high flows and floods . Over the past 80 years.
,an estimated 19 million cubic yards of sediments. tailings and
/ heavy metal sludges have collected in the ponds.
The Anaconda Cop Mining Compwy (ACM) made
the first attempt to control the anotmt of sedinlali carried into
the Clark Fork River from Silver Bow Creek in 1911 by
building a 20-foot high tailings dam on Silver Bow Creek near
the town of Warm Springs. This created Watn Springs Pond
I. In 1916 another 18-foothighdam wasbuiliat Warm Springs
by ACM upstream from the first dam, creasing Warm Springs
Pond 2. This darn subsequently was raised five feet so a soul
heightof 23 feetduring 1967-1969. Warm Springs Ponds 1 and
2 continued to trap and settle out sediment from Silver Bow
Creek.
A third and much larger 284oo high dam was built
upstream of Pond2by ACM between 1954 and 1959. primar !v
for sediment control. This structure created Warm Springs
Pond 3. The heightof thisdam was increased by five feet unng
1967-1969 to a ma.x.imtun height of 33 feet.
In 1967. Warm Springs Pond 3 was converted :nto a
treatment facility to treat mill losses, precipitation p Lint spent
I
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3
solution from Butte Operations, and overflow from the nearby
Opportunity Ponds. Treattnencconsistedofintroducingalime/
water suspension from the Anaconda Smelter into Silver Bow
Creek above Warm Springs Pond 3. The addiuon of the lime
suspension raised the pH of the creek water to help precipitate
hca y metals in the Warm Springs Ponds. Currently. the ponds
arc used to physically, chemically, and biologically treat Silver
Bow Creek surface water through sedimentation and chemical
and biological precipitation of heavy metals.
The current configuration of the Mill-Willow Bypass
•. as constructed about 1969.1970 while making improvements
to the Pond 3 berm. The Bypass was constructed to divert what
was thought to be relatively clean waler from Mill and Willow
Creeks around the pond system. Recent information obtained
from the remedial investigation indicates that concentrations of
metals in these surface waters are tugherthan originally thought.
In 1987 the berm between the Warm Springs Ponds and the
Mill-Willow Bypass adjacent to Pond 3 was raised by the
Anaconda Minerals Company (AMC) in an attempt to better
protect the irnegsny of the pond system during flood flows
The Wildlife Ponds were constructed about 1967 by the’
Montana Department of Fish and Game in association with
AMC. The purpose of the ponds was to enhance waterfowl
habitat in the upper Deer Lodge valley Two large cells and
several smaller sub-cells and islands were consu’uc ted for this
purpose. Water within the Wildlife Ponds is treated water frcm
Pond 3, and its quality is generally much improved o er the
quality of water entering Pond 3.
The Warm Springs Ponds system is operated b dantic
Richfield Company (ARCO), successor to AMC. irid the
Montana Department of Fish, Wildlife, and Parks (\tDFWP
Pond us currently not used in the treatment process .it j,e s t
because the pond is largely filled with sediment }4cAe cr
Ponds 2 and 3 are still used to treat the contaminat. Aater
flowing down Silver Bow Creek before it reaches the C .irK
Fork River Undercurrentoperaungcondiuons. the a’. .itLac c
storage capacity remaining in the ponds would allow them ic
used for this purpose for approximately 70 years
Ponds are part of a larger picture
Subsequent top of the Superfund law in 1980, and
following preliminary investigations and assessments, in Sep-
tember 1983 the Silver Bow Creek Site was placed on the
Superfund National Priority List. Since then. MDHES has
administered and directed the efforts to conduct remedial inves-
tigation/feasibility study (RI/PS) acuviues at the site.
As mentioned earlier, three other sites in the Upper Clark
Fork Ri’.er Basin have also been listed as Superfund sites.
These are the Montana Pole. Anaconda Smelter, and Mill town
Reservoir Superfund sites. MDHES and EPA identified 25
thfferentoperable um thesefourSuperfundsites. Toensure
that the most serious problems would be addiessed first. MDHES
and EPA prioritized the 25 units into high, medium, and low
priority categories. Those operable units with the greatest
potential for human health and environmental exposure have
received the highest priority for remedial action. MDHES and
EPk. identified the Warm Springs Ponds as a high priority
operable unit.
The Wag n ‘gt Ponds were identified as a high
priority operable unit because they are susceptible to flood and
earthquake damage, which potentially could release millions of
cubic yards of tailings. sediments containing tailings, and metal
precipitates into the Clark Fork River causing considerable
environmental damage downstream of the ponds. The Warm
Springs Ponds are not strong enough to withstand even a
moderate earthquake. A 100-year flood could cause extensive
damage to the berms supporting the ponds, while a 1.000 year
flood or probable maximum flood could result in a general
failure of the pond system.
In addition to the potential for catastrophic flood or
earthquake damage, the Warm Springs Ponds present signifi-
cant environmental and human health threats associated with
contaminated surface water, soils, and tailings. These contarni-
nated media, and their interaction, have contributed to recurrent
fish kills in the Mill-Willow Bypass and the Clark Fork Ri ’ .er.
the most serious of which occurred in July 1989 An estimated
j 000 fish were killed during that single episode.
The location of the Warm Springs Ponds operable ..riit.
in relation to otheroperable units at the Silver Bow Creek S.te
as well as other sites in the Clark Fork River Basin. played .i
significant part in determining the remedianon alternau’.es
available to achieve a permanent remedy at the Ponds. l
threats to human health and the environment at Warm Springs
Ponds can be aw bu ed toconlamination which has m iErated to
the Ponds from upstream sources, has passed through the
Ponds, or has been deposited within the boundaries of the
operable unit. The prunary vehicle for the migauon of con-
tamination to the Ponds has been, and continues to be. surface
water flowing from Silver Bow, Mill. and Willow creeks.
Surface water functions to transport other media, such .is
tailings and sediments to the Warm Springs Ponds V hile
surface water contamination upstream from the ponds I ike lv
will be reduced by future cleanup actions, until then and for the
foreseeable future, that surface water will require u’eatrnent to
reduce us toxicity as it (lows downstream into the Clark Fc’rk
River.
Some of the contamination at the Warm Springs Ponds
is located within theoperable unitandeitheris migrating or has
the potenual to migrate from the operable unit downstream
Othercontaminauonconunuesu,migraze from upstream sources
to the operable unit.. Therefore, source control measures in
some instances and migration management measures in other
instances will need to be used to achieve the Superfund statu-
tory mandateofassuring permanent protection of human health
and the environment,
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4
Site risks summarized
A Public Health and Environmental Assessment (PF A)
was conducted to determine the potential threat to human health
and the environment posed by coniamiflanLs present at the
Warm Springs Ponds. The no-action alternauve assessed in the
PHEA assumes continuation of current site operations and
conditions. The human health risk characterization of the site
includes potential health effects that are both carcinogenic
(cancer causing) and non-carcinogenic.
Health Risks
The contaminants of concern are inorganic metals such
as arsenic, cadmium, copper. lead and zinc and their com-
pounds. Potential human health risks from these and other
contaminants were calculated using current and future residen-
ual. occupational. and recreauonal exposure scenarios involv-
ing contaminated media (soils, sediments. water) and coniasni-
nation within the food chain (waterfowl and fish) The PHEA
exposure scenarios defined the amounts of contaminated media
that could be absorbed by quantifying each potential receptor!
media/exposure pathway corn binauon for the site. The scenar-
ios assessed consider current site conditions and take into
account potential future site developments (addiuonal recrea-
uonal use, new residential areas. etc.).
The maximum potential excess lifetime carcinogenic
risks for all site media under the current recreauonal scenario is
estimated to be 8 X tO” (eight chances in 100.000). The
maximum potential excess lifetime carcinogenic risks for all
site media under the current occupational scenario is an esti-
mated 2 X 10” (two chances in 10.000). In other words, if
assumptions concerning current occupational use are accurate.
a worker at the site is subjected to increased cancer risks
because of frequent and long-term exposure to the cotuami-
nated media. The increased risk is estimated to be two chances
in 10,000 which is a high cancer risk by EPA standards. EPA
considers acceptable a range of I X l0 ”to I X 10 ’ 7 (one chance
in 10,000 to one chance in 10,000,000). The maximum excess
lifetime potential carcinogenic risk for all sue media under the
future residential scenario is estimated ar2 X 10.2 (two Chances
in 100) No potential human health threat was identified from
exposure to noncazemsgemc contaminants for the current rec-
reational. the current occupational, or the future residential
scenarios.
Underthecurrentresidenual scenario, potential carcino-
genic risks were identified only for the inhalation and ingestion
of contaminated dust. At the town of Warm Springs, the excess
lifetime cancer risk for dust inhalation or ingestion ranged from
an estimated IX l0”(onechancern 1,000,000) to IX 10 2 (one
chance in 100.000). At residences east of the operable umi.
excess lifetime cancer risks due to dust inhalation or ingestion
ranged from zero to 9 X 10” (nine chances m 1,000,000). No
potential human health threat was identified from exposure to
noncarcinogenic contaminants for the current residential sce-
nario,
Environmental Risks
Undercurrent conditions, the average concent.rauons of
several site inorganic contaminants in surface water exceed
Montana standards for the protection of aquatic life The
chronic toxic effects of site contaminants may be expressed ii
local fish and wildlife populations through reduced crov .th
rates, reduced fertility, and increased mortality ; pnnc’ ’al
envu’onmental impact associated with the operable unit the
periodic fish kills in the ClarkForkRiver “vIDHES bdie’.es t’-c
kills result from the solubilizauon of metal saiLs tram uilrn s -‘
the Mill-Willow Bypass during summer rainfall e”ent C . r-
rent effects on other local wildlife populations are unkno”. i
Future adverse environmental effects v. ithout r rncd.a-
uon are expected to be similar to current conditions P r c
fish kills can be expected to recur and chronic conur’1 rar
effects (reduced growth, fertility, etc.) may be e prossed &fl
andJor wildlife populations. The potential also exists r .
catastrophic event (flood, earthquake) where the pcnd
bermscould be breached, releasing site contaminants that c ’u
adversely affect aquauc resources (fish and wildlife popu.,i.-
tions, aquatic habitat) for miles downstream
PUBLIC MEETINGS
Anaconda - Thursday, Nov. 9 at 7
p.m. in the Metcalf Center.
Missoula - Monday, Nov. 13 at 7 p m.
in the St. Patrick Hospital Broadway
Building Auditorium.
Butte - Wednesday, Nov. 15 at 7 p.m.
in the Mining/Geology Building, Room
206, at Montana Tech.
The Montana Department of Health and
Environmental Sciences will hold three
public meetings to discuss the options for
cleanup of the Warm Spnngs Ponds
operable unit of the Silver Bow Creek
Superfund site as discussed in this Proposec
Plan.
For more information, call Jarite Stiles,
MDHES, 1-800-648-8465, in Helena
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S
Ponds underwent careful study
In October 1984. MDHES contracted with MultiTech of
Butte cc perform a remedial investigation (RI) of the Silver Bow
Creek sue. The RI consisted of coordinated individuaj studies
to develop data on the extent and severity of contamination
within the entire sue. This Phase I RI included a study of the
Warm Springs Ponds.
In May 1987, MuluTech reported the findings of the
Phase I RI conducted for the ponds. Upon completion of the
Phase I RI, several data gaps were identified for which addi-
uonal information was necessary before a feasibility study (FS)
could be completed.
In February 1986, MDHES contracted with CH2M-H.ill
of Helena to complete Phase II Rl/FS activities at the Silver
Bow Creek site. Among the first investigations undertaken was
the Phase II RI for the Warm Springs Ponds. Phase II RI
activities began in October 1987 and CH2M-Hill reported the
findings of the Phase II RI in May 1989.
As a result of all previous investigations undertaken, the
following problems have been identified at the site:
1) Pond instability creates the potential for release of
contaminated pond bottom sediments to the Clark Fork River
during high flows, floods and earthquakes due to failui e of
the pond berms
2) The tailings in and along the Mill-Willow Bypass are
a source of high concentrations of dissolved metals and are the
likely cause of fish kills in the Bypass and Clark Fork River
during rainfall runoff events;
3) Tailings within the Mill-Willow Bypass continually
erode and transport dissolved metals and sediment to the Clark
Fork River.
4) Under normal flow conditions, the concentration of
dissolved metals in Mill, Willow, and Silver Bow creeks and the
Clark Fork River exceed those concentrations acceptable under
Stare waler quality standards;
5) The Warm Springs Ponds are ineffective in capturing
tailings transported by Silver Bow Creek during high flows and
floods. During these conditions a portion of the saearn flow is
routed around the ponds and transported to the Clark Fork
River, untreated,
6) A groundwater contamination plume exists within
andbelow Pond 1;and
7) There is the potential for unacceptable human expo-
sure to exposed tailings and contaminated soils within the
boundaries of the Warm Springs Pond operable unit.
Objectives of Ponds cleanup
0 ’
The existence of environmental and human health prob-
lems within the operable unit directly correlates with non-
compliance with applicable orrelevant an p require-
ments (ARARs) or unacceptable health risks, Ii is the ARARs
and human health protectiveness standerds which form the
basis of remedial action objectives. Remedial action objectives
are essentially site cleanup goals designed to address the
problems identified at the sue.
Based on the 1 thed problems, the results of the
Public Health and EnVironmental M isinenr , and the analysis
of ARARs, a list of renl ..dial action objectives has been identi-
fied for all of the mediaaz the site:
1) For pond bottom sediments, the remedial objective is
to prevent releases of the pond bottom sediments due to floods
or earthquakes. The Montana Depamnent ofNaniral Resources
and Conservation (DNRC) darn safety requirements have been
identified as the applicable standard. The standard requires
protecting the ponds to fractions of a probable maximum flood
(PMF) and to the maximum credible earthquake (MCE).
2) For surface water, the remedial objectives are to:
- Meet ambient waxer quality standards established pur-
suant to the Montana Waxer Quality Act for arsenic, cadmium.
lead, mercury, copper , iron and zinc ata”compliance point” just
above the defined starting point of the Clark Fork River
- Prevent ingestion of waxer within the operable unit
above the Montana Public Waxer Supply Act’s maximum
contaminant levels for arsenic, cadmium, lead, mercury and
silver, and above established reference doses for copper. iron.
lead, zinc, and cadmium. Also, prevent ingestion of water
containing arsenic in ccncentzauons that would cause excess
cancer risk greater than 1O to 10” (one chance in 10.000 to one
chance in 10,000,000).
• Inhibit the migration of tailings from the Mill.Wdlow
Bypass to the Clark Fork River in order to reduce the potenual
forfuuireexceedancesofamhienx water quality standards in the
Clark Fork River.
- Inhibit the migration of tailings from the upper reaches
of Silver Bow, Mill, and Willow creeks to the Clark Fork River
in order’ to reduce the potential for recontamination of the “till-
Willow Bypass and future exceedances of ambient waler qual-
ity standards m the Clark Fork River.
3) For tailings deposits and contaminated soil.s e
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6
remedial objective is to reduce the potential for direct human
contact, tnl lanon, and ingestion of exposed tailings and
contaminated soils posing excess cancer risks above 10 ’ to
10-’
4) For groundwater, the remedial objective is to reduce
the levels of ariemc. cadmium, and other contaminant con-
ceniranons in the groundwater in the Pond 1 area to achieve
compliance with Montana groundwater maximum contami-
nant levels.
Cleanup alternatives summarized
The remedial action alternatives that were developed
in the FS to address the site problems just identified are
described below. The numbering system used here is
consistent with the numbering system used in Chapter 8 of
the FS. The descriptions include the estimated present-worth
costs and the umeframe that may be required to implement
or complete the activity for each of the alternatives. In
general, the alternatives are presented in order of their
overall protectiveness in addressing the problems at the site;
Alternative 1 being more protective and Alternauve 7 being
the no-action alternative.
Ih addition to the cleanup alternatives, the Superfinid
program requires that a “rio-action” alternative be evaluated
at every site. The no-action alternative serves primarily as a
point of comparison for the other alternatives, but would
only be selected if human health and environmental risks
were found to be negligible. Based upon the risks present at
the site, MDHES and EPA believe that all the media (surface
water, groundwater, pond bottom sediments, and soils)
require remediauon.
AItern2tiv 1 ( L19 iOO.OOO
The components of Alternative 1 include solidifying
all on-site contaminated soils, tailings, sediments, and
sludges to protect against a probable maximum flood (PMF)
and a maximum credible eanhqrimke (Ma); coum’ucung a
new treatment pond for surface waler u menI and an
upstream flood impoundment to capuan flood flows for
additional treann jpd installing a groundwater intercep-
uon trench to apune and then treat contaminated groundwa-
ter as it migrates from the ponds
The current inability of the three existing ponds to
withstand floods and earthquakes would be addressed by
using an rn-site (in-place) solidifie2 on process to stabilize
the pond bottom sludges and sediments. This would mini-
mize the risk of pond failure due to an earthquake or flood
event. In addition, contaminated soils and exposed tailings
which exceed an action level of 250 parts per million (ppm)
for arsenic and 750 ppm for lead would be excavated and
disposed of in the existing ponds poor to soIidi&anc o.
This alternative would effectively limit the toxicity and
mobility of tailings to acceptable concentinuon levels and
greatly reduce the potential for future human or animal
contact with harmful con unan is
Alternauve 1 would also improve surface water
quality with the construction of a new pond treaunent
system. A new u’eaanenc pond would be constructed to
replace the existing, now solidified, pond system The new
pond would be capable of capturing and treaung flows up to
600 cubic feet per second (c(s). This is the flow the current
pond system is capable of treating.
In addition, an upstream flood impoundment (8.000
acre-feet) would be coasmicted to provide settling and -
treatment of flows on Silver Bow Creek up to the peak flow
of a 100 year flood (4,000 cfs). Currently flood flows on
Silver Bow Creek which exceed 600 cfs (the desi i hmit of
the Pond 3 inlet structure) are routed around the ponds.
untreated. A flow of 600 cfs on Silver Bow Creek repre-
sents, approximately, a two- to three- year return flood.
The goal of the upstream impoundment is to pres ent
large quantities of sedunents and dissolved metals from
bypassing the pond system and flowing into the Clark Fork
River. The impoundment would serve two functions. First.
it would serve as a conventional sedimentation basin: as the
velocity of the water entering the impoundment slows, the
sediment being transported by the flow would settle out.
Second. the impoundment would have the storage capacity to
contain up to the 100-year flood. The water would then be
metered to the ponds for treatment of dissolved metals, if
necesnary. Floods exceeding 4,000 cfs would be routed
around the impoundment to protect it from damage due to
overfiuing.
Contaminated groundwater moving from the operable
unit would be collected in an open trench constructed within
and below Pond 1. The collected groundwater would then
be pinriped to the inlet of the new pond for treamienc. This
would reduce the discharge of contamin 1 groundwater
into the Clark Fork River, and enable the aquifer to be used
for drinking water and other beneficial uses.
Alternative 1 is one of two alternatives expected to
exceed at 1e one ARAR. Whereas the DNRC safety
standards require protection of the existing ponci md 3
to 0.2,03, and 0.5 PMF, respectively, the rn-sit .. .:a-
iron process would provide protection of all thre
agair the full PMF. Alternative I is expected - all
other AR.ARS with one exception; surface waxer ..irds
for arsenic and mercury forprotecuon of public hearth from
ingestion of contaminated water and fish are technically
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4’
Reference 11.
Excerpts from Telecori between Maria Leet (SAIC) and Russ Forba
(EPA) on October 22, 1990.
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C
Contract No.___________
Originator I -
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Made Call Received Call Meeting at SAIC Meeting At
Persons) Contacted (Organization) L
SAIC Perwnnel ___________________
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A,
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Silver Bow Creek/Butte Area Site Mining Waste NPL Site Summary Report
Reference 11
Excerpts From Record of Decision, Silver Bow Creek/
Butte Area NPL Site, Warm Springs Operable Unit,
Upper Clark Fork River Basin, Montana;
EPA; September 1990
-------
RECORD OF DECISION
PART I: THE DECL4.RATION
Silver Bow Creek/Butte Area NTL Site
Warm Springs Ponds Operable Unit
Upper Clark Fork River Ba.sin, Montana
STATEMENT OF BASIS AN) PURPOSE
This decision document presents the selected interim remedial action for the War-rn
Springs Ponds, an operable unit of the Silver Bow Creek/Butte Area NPL Site (original
ortion), in the Upper Clark Fork River Basin of southwestern Montana. The selected
remedial action was developed in accordance with the Comprehensive Environmental
Response. Compensation, and Liability Act of 1980 (CERCLA), as amended by the
Super-fund Amendments and Reauthorization Act of 1986 (SARA), 42 USC Sec. 9601, . j
. and, to the extent practicable, the National Contingency Plan (NCP). 40 CFR
Part 300. This decision is based on the administrative record for the site. 1
All determinations reached in the Record of Decision were made in consultation with the
Montana Department of Health and Environmental Sciences (MDHES), which conducted
the Remedial Investigations and Feasibilit Study for this operable unit and participated
fully in the develQ 1ent of this Record of Decision.
Tim. I LnLItzatL,. r.cord t d.z d copi.. of k.y sit. doc .nts az. sv ..LL.bL. for pu Lic r.vi.w
st tb. P Ltc Lthr.ry. t.bs M ta a T.ch Librsz, oo W..t Pszk Stz..t th Ii tt.. d etb.:
tafor3.Uon rsposLtort.s lo th. CLark Fork 3uj Tb. c pLste s otstauv. r.cod say b.
r.vt. .d at tb. effic.. of tb. 0.3. EPA. 301 So , th P.zk. Tsd.ra . 3 i1.4thj. 1s u a. P .
1 .1
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4SSESSME I’T OF THE SITE
- :_a. nd :::ea:ened r eases ha: :: us _:s:a:ices rorn :n .s s . I ot a cr ss
ienien::ng trie response action seLec:ec in :his Recorc of Decision. may present an
.n-h.rrunent and substantial endangerment to public health, welfare, or the environment.
DESCR1PTTO’ OF THE REMEDY
The Warm Springs Ponds Operable Unit is one of eleven operable units identified as part
of the Silver Bow Creek/Butte Area NPL Site in the Upper Clark Fork Basin area of
Montana. The Warm Springs Ponds Operable Unit is located within Deer Lodge County,
approximately 27 river miles northwest of Butte and just above the confluence of the Mill-
Willow Bypass and Warm Springs Creek. Silver Bow, Mill, Willow and Warm Springs
creeks are principal headwaters streams of the Clark Fork River, which begins at the
northernmost boundary of the Warm Springs Ponds Operable Unit.
The operable unit covers approximately 2,500 acres that include three settling ponds, the
area below the Pond 1 berm to the Clark Fork River’s beginning point, a series of wildlife
ponds, and the Mill-Willow Bypass (see Figure 1). The remedy includes means for
controlling contamination associated with pond bottom sediments, surface water, tailings
and cont2minated soils, and ground water within the boundaries of the operable unit. The
selected remedy for the Warm Springs Ponds Operable Unit may be summarized as
follows:
• Allow the ponds to remain in place; Ponds 2 and 3 will continue to
function as treatment ponds until upstream sources of contamin2tion are
cleaned up;
• Raise and strengthen all pond bertns according to specified criteria, which
will protect against dam failure in the event of major earthquakes or
1 -2
1,
‘I,
-------
1
floods. and increase the 3:orage capac ’ , f Pond 3 to receive and : en:
flows up to the 100-year flooa:
• Coastruct ne’ inlet anc hycrawic ct’ es :o prevent deoris ±‘om
plugging the Pond 3 inlet and to saieiy route flows in excess of the 100-
year flood around the ponds;
• Comprehensively upgrade the treatment capabthzv of Ponds 2 and 3 to
fully treat all flows up to 3,300 cfs (100-year peak discharge) and
construct spiilways for rouung excess flood water into the bypass channel:
• Remove all remaining tailings and conza.rninazed soils from the Mill-
Willow Bypass, consolidate them over existing dry tailings and
contaminated soils within the Pond 1 and Pond 3 berm.s and provide
adequate cover material which will be revegetated;
• Reconstruct the Mill-Willow Bypass channel and armor the north-south
berrns of all ponds to safely route flows up to 70,000 cubic feet per
second (one-half of the estimated probable maximum flood);
• Flood (wet-close) all dry portions of Pond 2;
Construct interception trenches to collect contaminated ground water in
an below Pond 1 and pump the water to Pond 3 for treatment;
• Dewater wet portions of Pond 1 and cover and revegetate (thy-close) all
areas within the Pond 1 berms;
1 -3
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• Establish surface and ground water quality rnor cortng vstez s a c
- erform all otrie- 2:tIv t es ecessarv :o assure i:a c— . -- -
.a DiicabLe or re e a : anu a procr ate equ rernents.
• Implement institutional controls to prevent future residenttal
development, to prevent swimming, and to prevent consumption of fish by
burn iri ; and
• Defer, for not more than one year after the effective date of this
document, decisions concerning the rernediation of contaminated soils.
tailings, and ground water tn the area below Pond 1, pending evaluation
of various wet- and dry-closure alternatives and a public review.
Although the majority of Iciown tailings and contaminated sediments and soils deposits
within this operable unit will be rernediated by actions specified in this Record of
Decision, a final soil cleanup level is not selected. A decision regarding a final soil
cleanup level, which affects primarily the area below Pond 1, but also the Mill-Willow
Bypass and all diy portions of the ponds, will be made within one year of the effective
date of this document. In addition, the final decision concerning the ultimate disposition
of Ponds 2 and 3 must be deferred until upstream sources are cleaned up and the two
ponds cease to be needed as ueatment ponds. Each of these decisions will be subjected to
separate public reviews, during which a range of alternatives will be examined and public
input solicited.
The selected remedy presented in this Record of Decision attempts to permanently
rernediate the p rincipa1 threats posed by contamination at the site. The remedy will
reduce or e1imii, te most of the human health and environmental threats present at this
operable unit, but the remedy is an interim measure for the reasons stated below. Future
records of decision, or other decision documents, will direct cleanup actions at the other
operable units and NPL sites that affect Silver Bow Creek and the Warm Springs ponds.
‘-4
A
0
t)
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Unul those source areas are cleaned up. the effectiveness and permanence of tflzS reme v
cannot be fully or finally deternuned.
One component of the selected remecv presented in this Record of Decision departs
significantlY from the preferred remedy, as originally identified and evaluated in the
feasibility study and described in the proposed plan. Whereas the feasibility study and
proposed plan recommended construction of an upstream sediment settling basin, and as
a consequence, discontinuance of Pond 2 as a treatment pond, the selected remedy
presented herein calls for storage and treatment of flood flows (up to the 100-year event)
in Pond 3 and retention of Pond 2 as a treatment pond.
The rationale for this significant change is as follows:
1. There was considerable public opposition to the proposed upstream
settling basin. Residents of the Deer Lodge Valley were concerned about
economic and environmental impacts that might have been caused by the
impoundment.
2. Upon examination of an alternative proposal presented by the potentiall
responsible party, the Atlantic Richfield Company (ARCO), specifically to
store and treat flows up to the 100-year flood within Pond 3, the EPA and
State concluded that that is an acceptable alternative to the concept of an
upstrea.rn settling basin. In fact, treatment of dissolved metals in flood
rs would not have been a feature of the upstream settling basin:
however, such treatment will be possible once the selected remedy is in
place. This revised component of the selected remedy offers the
additional advantage of keeping cont n’in2nts within the e sting
boundaries of the operable unit.
1 -5
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While this deDarture represents a sigmflcant iarige to trie pre errec rernecv idenufied in
‘he rooosed clan, it was deve looec ‘ rOU c 5tr i ”e i3Jo ’. e ‘ Zh :he ubhc arid
.A.RCO. The overall re. eoial oojec es. a ...-ie . -_y and desc- ed
in the proposed plan, remain unchanged.
As a result of the dialogue with the public and ARCO, which followed a series of public
meetings concerning the proposed plan, :ne Mill-Willow Bypass Remo il Action was
initiated. On July 3, 1990, the EPA and ARCO entered into agreement through an
Administrative Order on Consent to undertake expedited action on the tailings and
contaminated soils along the Mill-Willow Bypass. In the process of developing a work
plan for this removal action, maly state and federal agencies, ARCO, and the public have
cooperated to assure that the extensive excavation, consolidation and disposal of tailings
and contaminated soils, and raising, widening, and armoring of the north-south pond berrri.s
are completed in a manner consistent with the overall remedy. At the time of signing of
this document, the removal action is proceeding well and invaluable experience has been
gained concerning site conditions, which will facilitate followup work prescribed in thus
Record of Decision.
DECLARATION
The selected remedy is protective of human health and the environment; attains and
complies with federal and state requirements that are applicable or relevant and
appropriate for this remedial action except where waivers, as noted, have been applied;
and is cost-effec E The remedy utilizes permanent solutions and treatment altemnauves
that reduce the toxicity, mobility, or volume as a principal element to the maximum extent
practicable for thu operable unit The use of treatment alternatives to address the human
health and environmental threats posed by the pond bottom sediments, exposed tailings,
and cont2mirtated soils was determined not to be practicable because of the extensive
volume of material present on the site and the absence of available technologies to
effectively treat the contaminants.
1 -6
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3e.a...se ± s :eme will :es i: Lfl . a ..dots . s:anc:s -camng onsite. a ie’ .
on uc:ed within i e years after co encerr er: of remedial action to esure a: :ie
e: . :cr ::: es .c r -de acect : ec::; h_a: heai: c : e e : e-:
AJd.:.onah, ne remedy seec:ec s R orc i Dec:sion iil oe su jec: :o a seDarace
7uoii review once work at the other NFL s:tes :iat affect this operable unit is completed.
Stg r iature:
- _ ,z _ . __ . _ . - , 4-i’- . F
—/ /
James J. Scherer Date
Regional Administrator (Region VIII)
U.S. Environmental Protection Agen .
1 -7
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s amps. The presence oi the pond syste m affec .s shallow v ound water eieva::cr. .s
:-d grDund ‘ .‘ a:er mc ement w thm the s::e
S:a! ou . aquifers oc ir along present-day 3:ream crianneis u: do not extend ateraJ .
: roughout the s:te. Deeper aquifers are associated with Tertiary-age valley fill and thick
deposits of glaciofluvial material. These aquifers generally exhibit moderate to low
?ermeabUitles and are probably connected on a regional scale, although tine-grained inter-
Deds tend to confine the deeper aquifers locally.
The uppermost aquifer at the site is a 10- to 15-feet-thick sand and gravel unit, which s
r .pically present approximately 10 feet below ground surface. This sand and gravel aquifer
appears :0 he present throughout most of the site. Ground water movement through the
.s erieraUy south to north, although a significant component of ground water enters
from the O poruni Ponds area to the southwest. (See Figure 2).
No domestic well is located within the Warm Springs Ponds Operable Unit. Several are
located east of the pond system within a mile of the operable unit, but these wells are
completed in bedrock aquifers that do not appear to be affected by the pond system. The
town of Vvarm Springs derives its water from supply wells constructed in unconsolidated
Tertiary deposits, from depths of approximately 200 feet. These wells appear to be
supplied with water derived from ground water resources west of and hydraulically isolated
from the Warm Springs Ponds.
4.3 NATURE AN EXTENT OF CONTAMINATION
Sediments, surface water, soils, and ground water are all affected by contaminants in the
Warm Springs Ponds Operable Unit. A schematic that shows the contaminated areas and
the migration pathways is presented as Figure 3. Four contaminated media have been
identified for the operable unit: pond bottom sediments, surface water, tailings deposits
and contaminated soils, and ground water. The media are discussed in the following
2-9
p 1
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I ’ )
TABLE I
SUMMARY OF .AR.EAS C’ D VOLUMES OF COYTA.\IINATED MEDIA
(acio4 t) ( )
ocrom Sc ime,t
?ond 1
P .’ 4 Sedemee 59 734
Vet4/Su rge4 Scdime u 2 S60oo
Pond 2
Exposed Sed, erns o 1.300000
Vegeu crg Scdu cn&z . 3 590,
S02 3 030 4390.000
Pond 3
Submerged Sedimenu cJ 6903 11180000
cal Pond Bottom Scdimc . -$1 11.753 18960.000
Su ’aee Water
i,i er Bc Czcck’
‘.lil! and wiu Cr b
a;lin Der omrs and Co lm wed Soti
Mi1J.Wt11 BypwC
Exposed Taa linp 21 47 5300
Vegetated Tadtnp & Contaminated Sod .1 . 130000
54 1 : 7 2 OSS O O
Area Abo e Pond 3
F pri .d Tathnp 22 36 90.300
Vegetated Tadiep & Contaminatcd Sod . L130.000
290 756 1.220.300
A Pond I
Ex sd Tathnp 17 48 77.400
Vegeeaeed Tadiap & Comamsnazcd Soil 39’ 000
76 294 474.100
Ground w i fe ? 4
Ar ‘- ‘.l sq d.r bsncac & do nps4 ent o( Pond 1 180
‘flo.’ ringos tense 412 (75 ai aizs) . Data collection tense Mazeh 1985 to Aug 1
tangos from 3.17 (27 ó a azq.J Data tec? from Dcceinbee 1984 to Aug 19g.
C ft Bypsat thIiI.pL sad aoi are being remowed by an expedited acoon atbeduic far compeetton ta Nowember
& pnmaay mum iswe for vacate sa os miom .
2-13
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secuons. Ta presents a breakdown of the areas and volumes for each of the four
niedia.
.L 3.1 Sediments. Tailings, and Contaminated Soils
Two of the media—the pond bottom sediments, and the tailings deposits and cont2minated
soils—contain the majority of the cont2rnir!ants in the Warm Springs Ponds Operable Unit.
These materials are typically fine to coarse sand and generally contain metals associated
with the sulfide ore body present near Butte. Pond bottom sediments are also comprised
of precipitated hydro des and oxyhydroxides resulting principally from the addition of lime
to treat the water entering the pond system and from biologically mediated precipitation.
The e cposed unsubmerged) sediments, tailings deposits and contaminated soils cover an
area of approximately 634 acres within the Warm Springs Ponds Operable Unit.
rnick. esses of these deposits range from less than 1 inch to several feet. The submerged
sediments in Ponds 1, 2, 3. and the wildlife ponds cover an area of approximatel>
1 227 acres and range in thickness from less than 1 foot to over 20 feet. (See Table 1)
4.3.2 Surface Water
The data obtained during the remedial investigation characterize the surface water for
near-average flow rates. Few data are available to characterize the surface water quality
during higher flows because of drier-than-normal conditions in the area experienced during
the remedial investigation. No opportunity was available during the sampling period to
collect flow and cont2mination data during one of the high runoff events that cause inflows
to be diverted around the pond system.
Surface water samples were collected at 25 sampling points in and adjacent to the Warm
Springs Ponds Operable Unit during Phase I and Phase II remedial investigations. The
Phase I remedial investigation showed that metals are being removed from the Silver Bow
2 - 12
f l , 1
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1
Zreek ow by the cur :: pond trea ent system. Inflow loads oi total copper and totaz
znc were reduced by over 90 percent by the time the water left the pond System during
: e s .unmer months and by 50 :o 0 percent dur ng winter months. Although metals
:oncentratjons are reduced in the pond system, Montanis chronic ambient water quality
standards for copper, lead, and zinc were occasionally exceeded in the water leaving the
pond system, particularly in winter months. Ambient standards for cadmium and iron
were also frequently exceeded during the sampling events.
Four 24-hour, or diurnal, sampling episodes were completed within the Warm Springs
Ponds system during the Phase 11 remedial investigation to gain a better understanding of
changes in water quality over 1-day periods and on a seasonal basis. These sampling
episodes were completed in September 1987 and in January, April, and July 1988.
Hourly data from the diurnal sampling studies have been compiled. 4
The data for the 24-hour sampling episodes indicate the following:
• pH varied by up to 2.2 units throughout the day at all stations sampled.
• Total metals concentrations decreased 50 to 90 percent between pond system
inflow and outflows.
-. Dissolved metals concentrations for copper and zinc were generally 20 to
50 percent higher in the winter at all sampling stations in the pond system.
Higher dissolved metals concentrations in the winter correlate directly with lower
pH values measured during winter sampling events.
cwi an.i.. u s a fta ss :: &...4L.1 v .ztiit on Dazi
2- 14
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The pond system reduced metals coricen:rations at the outflows from the s’stem during the
:our ciurnal sampling events. frequently :0 evels ociow o:n .nroruc arid ac’..ite acuat:c
si o s an exanipie of :ri s prieriorrienon recorded durtng one of :ne
diurnal sampling events.
Removal of metals in the ponds is accomplished by physical, biological, and chemical
processes. Pb ’ sicai reduction of metal-bearing solids occurs through simple sedimentation.
Increases in pH, which are partly due to the addition of lime and partly due to
photosynthesis, can precipitate metals as a result of changing metals solubiliues. Yet
another important metals removal mechanism may be the precipitation of calcite and
coprecipitation of metals and phosphorus, which follow the photosynthetic removal oi
carbon dioxide and a compensating shift in the bicarbonate buffering system. 5 Direct up-
take or absorption of metals by algae and aquatic macrophytes is also probable. Addition
of lime to the Silver Bow Creek inflow during the winter months also contributes to
precipitating metal contaminants when the amount of sunlight to support photosynthesis :s
reduced.
Several fishkills have occurred in the Mill-Willow Bypass and in the upper Clark Fork
River, with the most recent known episode being in July 1989. Analysis of fish ussue by
Montana Department of Fish, Wildlife, and Parks from one event in the summer of 1986
revealed acute copper poisoning as the cause of the fish mortality. Although MDF ? did
not determine the source of metals responsible for the killings, that source most hkeiv
consists of tailings material along the Mill-Willow Bypass.
W.Is.L. LG. • 1173. Li e1oi ThiLsd.Lp i. W 3 S. d.rs C p y.
2-15
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4 (N) - --
-. .-.-.-. ---.---. --—.1.-- -
I.
i 1r1—r-rrT
NOTE:
BASED ON PHASE U RI.
24 HOUR SAMPLING— —SEPTEMBER 19B7
Ambient Water Quality Standards
Based on Average Hardness 01160 mg/i
::: -L .-.__
- t r T 4 iri
SS—20 SS—22 j2S PS—12
POND 3 POND 2 POND 1 2 POND 2
INLET OUTLET
FIGURE 4
‘4
3
z
0
I-
I-
0
z
0
U
100
200
I)
DISS. COPPER
—, I I I v i TTr
“—I.
POND 3
INLET
ACUTE
STANDARDS
‘CHRONIC
5 TANDARL)
a.,
DECREASE IN
COPPER CONCENTRATIONS
THROUGH THE POND SYSTEM
WARM SPRINGS PONDS
SOURCE: PHASE II RI REPORT. CH2M Hilt 19R9
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.3.3 Ground Wat
3rounc wa:e ;u ’ . :a:a ere enera:ed :hr ugr sam:.. g u:or ng he_s : r o
occasions t Jariuary and May. :988) Figure 5 shows :ne .ocauocs of :ne monitoring veUs at
the site. Table 2 summarizes ground water quality data for these monitoring wells.
Ground water beneath Ponds 2 and 3 may be contaminated also. Wells were not installed
:0 determine the quality of the ground water beneath those rwo ponds. Given the
h drogeology of the site. contaminated ground water under the ponds would flow north
and be detected at the northern end of the pond system.
With one exception, all detected exceedences of the primary maximum contaminant levels
for metals (arsenic and cadmium) were north of the Pond 1 berm. Ground water cualit
c wnaracient of Pond 1 is generally of poorest quality immediately north of the berm.
most metal contarruriants decrease to the north. or downgradient of the pond system.
Concentrations of rnost metals also decrease with depth.
Highest concentrations of metals are generally associated with the shallow sand and gra e
aquifer in the area immediately below the Pond 1 berm. Calculations of ground water
discharge from the area below Pond 1 into the Clark Fork River indicate that the grounc
water system contributes very little flow to the river because of the relatively low
permeability and low gradient of the shallow aquifer. Under average conditions, the flow
in the Clark Fork River is appro .mately 137 cfs, while the ground water discharge to the
river is appro mate1y 1.0 cfs. Nevertheless, the exceedences of the maximum contaxn.inant
levels for arsenic and cadmium in the ground water constitute a violation of the drinking
water standards.
2• 17
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.‘.‘... •1
I.
‘ sj
-•-
• • ‘S. ••. • • • •.. .•• ‘ • .:
ii -,
1’ I )
•!.1 •.. I -.;.. -I
-
- I -
—‘
r :. ....!
I
ii. ..
. 3
—
I :
.j•.•. •-•t
• /_:
- !, -.••__•
fI #
• ! •
:-- -_‘ 3—%
•I
I.
I
r a - t-
1
••
••‘ :
—
‘S. ..
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—
_
SCA tW fUr
2000
LOCATION OF
£ PHASE I OHITORING WELL
• PHASt U MQP tQ PIQ WELl.
PHASE I PuIaPw4a WELL
FIGURE 2-13
‘ (IS (2
-------
tkW2.
Oe ’.D WAT QeAur DAt¼
WAR.\ ‘R , ICS PON OP . j2 L TT
____ Mu ______
_ Le a) 4onn G ’
of S pL wa Rqta aaons
.. .pçad s Monaorw
2.0 4.
.0’
- j 3
Manganese <3. .3 3
7 . ..r ic 4 10.3
Iron < 150 19 3 yc
Sulfate (mg/i) 680 49 250 ’
,GII-W J By ( aU Wclk)
‘ scn ic 2 <2.0 0 So
Cadmium :: <50 3 10 b
Ccp e .50 <6.0 46 10 1.0C C ’
Lead IS <10 2.5 10
Manganes.c 14.500 45 4 5S 10 50 ’
265 10
Iron 4000 305 10
Sulfate (mL ’I) .X 563 10 250’
Mzll-Vf Bvpaz (Deep Weli )
cC . . 3
Cadmium <52 3
Copoc- ‘1 <60 3
< IC S s0
Manganese S.S SC 73 2 221 8 SC’
Zinc 380 6 . : 8
Iron ‘0 <25 33 8 3 0 0 ’
Sulfate (mg/I) 1.060 9.0 4°4 8 250’
adienI o( Pond 1 ( a11 Wefla)
1970 <2.0 28.3 13
Cadmium :2.7 <50 36 14 10
Copper 159 <60 5.8 13
Lead <2.0 <1.0 2.0 14
Manganese 31.600 309 10.297 14 50 ’
Zinc 253 16.3 390 14 50 0 0 ’
lron - 30.900 45 :6.. o 14
Sulfate (mg/I) 1.o20 250 950 14 250’
D adicnt of Pood I (Deep Wç
Arsenic <3.0 <2.0 1.0 13 sob
Cadmium 8.4 <5.0 4.3 13
Copper <10 <6.0 3.5 13 1.000’
Lead <2.0 <1.0 0.8 13
Manpneac 4,460 30 S 13 SOC
43 6.2 19.8 13 5.000’
Iron 409
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0
5.0 APPLICABLE OR RELEVA AND APPROPRIATE REQLTIREME rS
Applicable or relevant and appropriate requirements (ARARs) are a basic standard by
. .hich all aspects of conta.minant cleanup are measured. Compliance with ARARs or
invocation of an appropriate ARAR waiver, is required by Section 121 (d) of CERCLA
The feasibility study evaluated potential compliance of the developed remedial alternatives
th federal and Montana ARARs. Compliance with ARARs is a threslihold
determination for selection of a remedy. 40 CFR § 300,430(f)(i)(A).
The discussion of ARARs in this section is a general discussion, which highlights the major
ARARs for the remedial action. A full list of all ARAR.s and compliance points, as well as
: formation to be considered (“TBCs ), and other relevant legal requirements, is contained
:ri the attachment to Part II: The Decision Summary. The basis for EPA’s selection of
the ARARs is given in the feasibility study and Part III, Responsiveness Sumrr arv.
.ARARs are divided into three categories: chemical-specific, location-specific, and action-
specific. Chemical-specific ARARs include laws and regulations that set human health- or
environmentally-based numerical values governing materials having certain chemical or
Dhysical characteristics. These values set the acceptable concentrations of chemicals that
may be found in, or released to, the environment Location-specific ARARs restnct
contaminant concentrations or cleanup activities due to the site’s geographic or physical
location. Action-specific ARARs are based on actions taken during contarnin nt cleanup.
Section 121(d)(4)ofCERCL 42 U.S.C. § 9621(d)(4), provides for the waiver of ARARs
if certain criteria are met. This Record of Decision waives two ARARs for surface water—
arsenic and mercury—and establishes replacement numeric limitations for those standards
waived. The waivers are based on technical impracticability from an engineering
perspective, as permitted under section 121(d)(4)(c) of CERCLA, 42 U.S.C.
2 - 20
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ô21(c (4 (c . The replacement ruer:a w i a: fullY r teci: e of man
e:or..e :. The e lac ..en: ::ena :e
Mercury 0.3002 mg,’l
A.-seaic: 0.02 mg/i
There is uncertainty over whether creation of permanent disposal facilities within Ponds I
and 3 and the Pond 2 and 3 impoundments in place is in compliance with a relevant anc
appropriate requirement from the State’s Solid Waste Disposal Regulations, hich
prohibits disposal of solid waste within the 100-year floodplain. EPA believes that the
xaste units will be outside of the floodplain when the Pond berms are raised arid
strengthened to specified standards. Even if the water within the ponds is considered part
.f the floodplain, the disposal units are probably outside of the 100-year flood pool of the
. .ater within the Ponds. To the extent the areas within the pond berrns are considered to
e within the 100-year flood plain, EPA waives the Solid Waste Disposal ARAR pursuant
to section 121(d)(4)(c), as technologically infeasible from an engineering perspective a d
pursuant to section 121(d)(4)(A), as an interim action.
Additionally, if it is later determined that the area within the Pond berrns is within the
100-year floodplain, then a waiver of the state’s solid waste disposal regulations,
prohibiting disposal within the 100-year floodplain, is invoked, on the same bases as above.
51 CHEMiCAL-SPECIFIC ARARs
The most significant state and federal chemical-specific ARARs consist of standards
protecting the quality of surface and ground water resources for hurn n health and
environmental purposes. Surface waxer ARARs include ambient water concentration
limits to protect both aquatic life and public health, point source discharge standards for
discharges from the pond System, and drinking water standards. Ground water ARARs
include only drinking water standards. The contaminants of concern at the site a. e
arsenic, cadmium, copper, iron, lead, silver, selenium, mercury, aluminum, and nc.
2 - 21
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f 2 LOCATION-S?ECWIC ARARs
iocauor. wec .± c AR.ARS c .ide :le : act:v ’ . es: c:c :c rc:ec:
rnmize impacts on nistonca1l si iflcant features and endangered speces.
5.3 ACflON-SPECiFIC ARARs
Action-specific ARARS pertinent to the Warm Springs Ponds Operable Unit include
regulations concerning dam safety in event of floods and earthquakes, hazardous waste
management and land reclamation for mining areas.
Dam safety re ulauons address berm design and modification for the existing treatment
system. Hazardous waste management ARA.Rs include requirements for contarriiriant
disposaL Reclamation ARARs require proper grading, bacI lling, subsidence
stabilization, water control, revegetation and other measures needed in surface rrur ..irig
areas to eliminate damage from soil erosion, subsidence, landslides, water pollution, and
hazards dangerous to life and property.
2-22
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5ECT1O 6.t)
SUMMARY OF HUMAN HEALTH . ND ENVTRO’MENT4L RISK5
A p oi c ricaith and nvtron.rnentai sk assessment as conducted by the Montana
Department of Health and Environmental Sciences to identify and characterize the actual
and potential threats to human health and the environment posed by conrarttinants present
at : e Warm Springs Ponds Operable Unit. Carcnogenic and noncarcinogenic human
ealth effects were characterized, as were significant environmental effects. With respect
to both human health and the environment, endangerment was established.
6.1 HUMAN HEALTH RISKS
The EPA has determined that the Warm Springs Ponds Operable Unit poses the following
actual or potential endangerment to human health:
• Workers at the ponds face an increased risk of cancer estimated to be 2 x 1O ,
or two excess cancers in 10,000 individuals exposed for a lifetime, due to
incidental ingestion of arsenic in the contaminated soils, sediments and tailings.
Recreationists (hunters, fishermen, bird watchers) also face increased cancer risk
from exposure to arsenic.
• Workers and recreatioriists face additional cancer and noncancer health risks due
- to ingestion of lead and other hazardous substances in the contaminated soils,
sedirrn’nrc . and tailings .
• Current. residents adjacent to the ponds face actual or potential risks from
contaminated soils, sediments, and tailings becoming wind-borne. If homes were
to be built within the operable unit boundaries, residents would also face risks
greater than the levels noted above.
2-23
I l )
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• The contaminated ground water below Pond 1 poses a potenuai threat to u.sers
of the groi. .nd water.
• The berms protecing the ponds fail to meet current darn safety standards. Their
failure due to a flood or earthquake could result in catastrophic consequences,
inciuding loss of life.
The baseline risk assessment establishes current and potential threats to human health.
40 CFR § 300.430(d)(4).
The NC? states that the goal of a Superfund cleanup should be reduction of risk to
acceptable ranges, if ARARs do not exist or are not sufficiently protective. The point of
departure, or target risk range, is 1 x 1O for cancer risk and levels that do not create
adverse effect, incorporating a margin of safety, for system ic toxlcants. 40 CFR §
300.430(e)(2)(i)(A)(2).
The preamble to the NCP states that the 1 x 10’ risk range should be the goal of a
cleanup, unless revision to a lesser protective level is appropriate for site specific reasons.
55 FR 8715-8717. Risks should not exceed 1 x IO .
6.2 SUMMARY OF TOXICiTY ASSESSMENT
Arsenic, a known carcinogen, is present at this operable unit. Samples of exposed tailings
and contaminated soils contained a maximum arsenic concentration of 597 mg/kg and an
average of 349 mg/kg arsenic. Lead, a hazardous substance that is both a suspected
carcinogen and toxic noncarcinogen, is also present at elevated concentrations (maximum
of 1000 mg/kg and average of approximately 490 mg/kg). Risks from lead were not
quantified in the risk assessment, but the presence of lead risks is noted. In addition to its
suspected carcinogenic effects, lead is known to damage the central nervous system and
cause other serious health effects. The EPA believes there is no safe threshhold for lead
2 - 24
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intake. Other hazardous substances, sucri as cacrn.iurr a:e a’so present at &e a:ec
o nc:ntrauo ris.
6.3 SUMMARY OF EXPOSURE ASSESSMENT
In addition to serving as an active water treatment system for contaminants transported by
Silver Bow Creek, the Warm Springs Ponds and surrounding area also function as a
wildlife management area. Since two employees of the Montana Department of Fish,
Wildlife and Parks work within the operable unit, managing the wildlife area, their
occupational exposure was evaluated. A recreational exposure scenario was also evaluated
because hunters and Eshermen are often present at the ponds. The risk to current
residents was evaluated because several homes are located near the operable u ut
boundary.
As required by EPA policy, the risk assessment also examined risks under a future
residential scenario. Because the operable unit is comprised almost entirely of the ponds
and associated wetlands, EPA considers it unlikely that homes will be built within its
boundaries. To ensure that future residential development does not occur, the Record of
Decision requires implementation of institutional controls. The remedy then focuses on
active measures to address the occupational, recreational, and environmental threats.
The current humpn exposure routes are summarized on Figure 6 for each exposure
scenario. The principal component of human health risk comes from incidental ingestion
of arsenic duri occupational activity.
6.4 RISK CHARACTERIZATION
The risk assessment evaluated risks from carcinogenic elements such as arsenic, lead, and
cadmium, and risks from numerous noncarcinogenic elements such as copper, iron, lead,
and zinc. The hum n health risks from noncarcinogens are evaluated based on their
2-25
4;)
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-p
It ________
FIGURE 6
POTENTIAL CURHENJ HUMAN
r’AThwAys OF EXPOSURE
WAIIM SPHIN I fl I r
Adjacent
I tesudents
CtianneI/ - I flio oncenIra i i,i
I-
U
UI
I)
I
I I
0
I
I
0i
I
(1
C)
C.
sti
‘U
-------
hazard index. If the combined chemical hamd index is eater than one (based on a
detailed calculation presented in the risk assessment), then an unacceptable risk is present.
Although some risks due to :ioncarcinogens were found, the hazard index was in all cases
less than one. As indicated previously, lead was not quantitatively evaluated in the risk
assessment. However, the EPA believes there is no safe threshhold for lead intake.
Although copper and nc do not present a risk to human health, they do pose significant
risks to the environment, especially to aquatic organisms.
The maximum excess lifetime cancer risk due to arsenic exposure (arsenic is the
contaminant of primary concern) for workers at the ponds is estimated to be 2 x 10’, or
rwo excess cancers in every 10,000 exposed individuals. This estimated risk is based on
exposure to maximum measured concentrations of arsenic in exposed tailings and
corirarrunated soils present at the Warm Springs Ponds, but excluding the Mill-Willow
Bypass.
Because of difficulties in developing risk-based cleanup levels for the occupational and
recreational scenarios, EPA has elected to delay selection of a specific health-based soil
cleanup action level. The EPA will continue to examine appropriate methods for
calculating specific soil cleanup levels for this operable unit. Nevertheless, EPA 1.5
confident that the risk assessment has demonstrated actual and potential risks posed by
conditions at this operable unit to justify the Record of Decision requirements. The next
section, concerning environmental risks, explains how the human health risks will be
reduced by mitigation of the environmental risks.
63 ENVIRO NTAL RISKS
The EPA has det rmined that the Warm Springs Ponds pose the following actual or
potential endangerment to the environment.
2 - 27
ti
A,
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tc
• Periodic tishicilis have occurred due to salts o copoer a.rid zinc wa.shing from
:a±ngs de osits into the Clark Fork River curiuig thunderstorms. Contaminated
soils, sediments, and tailings also pose an uncuant flabie cnronic risk to aquatic
iie and wildlife, both within the boundaries oi :he operable unit and in the river
downstream.
• Water quality criteria for the protection of aquatic life have been exceeded by
water discharged from the ponds, and by water routed around the ponds without
treatment.
• The berms protecting the contaminated pond water and sediments fail to meet
current darn safety standards. Their failure due to floods or earthquakes could
result in catastrophic environmental consequences u’i the Clark Fork River
Although this Record of Decision does r it require a specific soil cleanup action level,
EPA is confident that the risk assessment has sufi ciently demonstrated the actual and
potential environmental risks posed by conditions at the Warm Springs Ponds to justify the
cleanup requirements.
The actions required by this Record of Decision are necessary and appropriate to address
the risks described above, even though an exact quantification of acceptable risk levels was
not determined. The actions required will reduce or eliminate the principal risks. This
statement is based on the knowledge that several components of the selected remedy
require excavati or covering of exposed tailings, sediments, and contaminated soils. For
example, drying and covering Pond 1 will retard or stop the ground water contamination
which currently exists, and increasing the operational level of Pond 2 will flood areas of
contaminated soils, sediments, and tailings, thereby reducing exposure by direct contact to
those areas.
2-28
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J :o 30 ?ercent of the suspended solids woui continue :o be setiled t vithin : e
D25Lfl but only flows up to 600 cfs (the inlet Capacity 0 f Pond 3 would then be ::ea:ed .r
•::e ;czds :r issoi ed ne:a s. The : a.ri .i : e ::scharzed o e: the SpLL a o
: e se:: ng • asin ouid be routed arouna Po c 3 c :1o :ie brass z:cL:
:reatrnent of dissolved metals.
The actions proposed in Alternative 3 are expected to result in compliance with all Sta:e
and federal ARAR . These include Montana’s darn safety standards, aquatic water qualnv
standards (with the exception of arsenic and mercury, as previously described), maximum
contaminant levels, and selected RCRA closure requirements.
The actions proposed for Alternative 3 are technically feasible ane are expected to re abiv
reduce the environmental and human health risks at the site. The actions proposed na
-esult in adverse effects to wetlands, endangered species. or historical resources. The
estimated present worth cost is S71,100,000. ft is estimated that the remediation measure
:denufied will take 5 years to complete.
8.4 ALTERNATIVE 3+3A S(57,416,000)
Alternative 3+3A, identi ed by the EPA and MDHES as the selected remedy, is a
synthesis of Alternative 3 and ARCO’s Alternative 3A. Alternative 3 + 3A was developed
following consultation with the public and ARCO to address concerns about some of the
aspects of Alternative 3 as pres ted in the feasibility study. Alternative 3 +3A i ciudes
many of the fe1 es of Alternative 3, including protecting the pond berxris against the
maximum credible earthçiake and fractions of the probab’e maximum flood, upgrading
the treatment sys’tem, reoving Mill-Willow railinp , covering and revegetating Pond 1,
and installing ground water interception trenches. It is different from Alternative 3 in that
storage of flood flows would be within Pond 3 rather than in an upstream impoundment;
the bypass channel would be realigned in places; Pond 2 would be improved and retained
2. 50
0
1 ’ ,
-------
( )
Pond stability in this alternar.ive is achieved by protecting Pond 1 against a 0.2 PMT. Pond
2 against a 0.3 P vff , and Pond 3 against a 0.5 PMF These are the standards th : are
-equired by Monta. ‘ . ai safet’i :e uiatioas for Sigh Saza.-d dams such as those a: : e
• ‘ arm Spring Ponds.
In Alternative 3, all exposed tailings and contaminated soils in the Mill-Willow Bypa.ss.
within Pond 3, and below Pond 1 that exceed an action level of 250 ppm arsenic and
50 ppm lead would be excavated and disposed of in Pond 1. Pond 1 would be ciosed
with a RCRA-compliant cap as described in Alternative 1.
Consolidating excavated material into Pond 1 under a RCRA-corxipliant cap would
effectively isolate the material from direct contact and effectively limit the mobility of the
material. It would also effectively consolidate all material which exceeds the cleanup
criteria within a smaller area. As long as the cap is properly maintained, the material
would be safe from release because of erosion of the cap.
The final difference between Alternatives 2 and 3 is that Alternative 3 includes the
construction of a smaller upstream settling basin (2,000 acre-feet). During flood flows on
Silver Bow Creek greater than 600 cfs, surface water would pass through the upstream
settling basin. The settling basin would be similar to the upstream impoundment with t o
exceptions. First, the storage capacity would be much lower (2,000 acre-feet versus
8,000 acre-feet). Second, the amount of water that would receive full treatment for both
suspended solids and dissolved metals would be less.
During flood flo between 600 and 4,000 cfs, all surface water from Silver Bow Creek
would pass through the upstream settling basin. Full treatment would be provided for
floods that do not completely fill and then overflow the 2,000 acre-foot settling basin
Suspended solids would settle within the basin and the captured water would then be
released slowly from the basin for treatment of dissolved metals in Pond 3. Floods that
exceed the storing capacity of the settling basin, however, would be only partially treated.
2 - 49
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Up to 80 percent of the suspended solids would continue to be settled out within the
basin, but only flows up to 600 cfs (the inlet capacity of Pond 3) would then be treated n
the ponds for dissolved me:als. The remainder of the flows discharged over the pi1l av of
the se:tLing basin would be routed around Pond 3 and 1ow down the bypass without
:rea ent of dissolved metals.
The actions proposed in Alternative 3 are expected to result in compliance with all State
and federal ARAR . These include Montana’s dam safety standards, aquatic water quality
standards (with the exception of arsenic and mercury, as previously described), maximum.
contaminant levels, and selected RCRA closure requirements.
The actions proposed for Alternative 3 are technically feasible and are expected to reliably
reduce the environmental and human health risks at the site. The actions proposed may
result in adverse effects to wetlands, endangered species, or historical resources. The
estimated present worth cost is 571,100,000. It is estimated that the remediation measure
identified will take 5 years to complete.
8.4 ALTERNATIVE 3+3A 5(57,416,000)
•Alternative 3+3A, identified by the EPA and MDHES as the selected remedy, is a
synthesis of Alternative 3 and ARCO’s Alternative 3A. Alternative 3+3A was developed
following consultation with the public and ARCO to address concerns about some of the
aspects of Alternative 3 as presented in the feasibility study. Alternative 3+ 3A includes
many of the feat .cs of Alternative 3, including protecting the pond berms against the
maximum credible earthquake and fractions of the probab maximum flood, upgrading
the treatment system, removing Mill-Willow tailings, covering and revegetating Pond 1,
and installing ground water interception trenches. It is different from Alternative 3 in that
storage of flood flows would be within Pond 3 rather than in an upstream impoundment;
the bypass channel would be realigned in places; Pond 2 would be improved and retained
2 - 50
-------
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fl)
Silver Bow Creek/Butte Area Site Mining Waste NFL Site Summary Report
Reference 12
Excerpts From Silver Bow /Butte Site Profile,
Document #983-TS1-RT-icrrR; Author Not Provided; Undated
-------
TABLE 1].
SUMMARY OF DOMESTIC wELLS(a) EXHIBITING FEDERAL DRINKING WATER
STANDARD EXCEEDENCES
Sulfate Cadmium Iron Arsenic Zinc
DW—13]. DW—206 DW—131 DW_230(b) DW—132
DW—132 DW—336
DW—202 DW—337
DW- 207
DW—311
DW— 314
DW— 3 18
DW—504
Notes : -
(a) Well locations shown on iiap 7.
(b) Exceedence measured was for total fraction; corresponding
dissolved fraction was less than standard of 0.05 mg/I ..
—32—
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Impacts to Silver Bow Creek measured during the RI are described below,
presented as percent contributions to the creek and gross material
loadings. Table 7 summarizes ground-water loading to Silver Bow Creek.
Host, if not all, of the contaminant loads in the Metro Storm Drain (MSD -
that portion of Silver Bow Creek which flows through Butte) were derived
from ground water, although some of the loads may be from sediment
re—entrainment. Ground water from the MSD was a significant source of
zinc, cadmium, sulfate, copper, iron, arsenic, and lead to Silver Bow Creek
at the confluence with Blacktail Creek, and it degraded water quality at
that point. Table 8 shows a ranking of contaminant sources to Silver Bow
Creek with loads in lbs/day.
A significant inflow of contaminated ground water was present between
Montana Street and the Colorado Tailings. Large increases in copper, zinc,
sulfate, arsenic, and cadmium loads are apparent in this reach.
Ground—water inflov here must be of extremely poor quality to cause these
drastic increases in metal loads.
Another significant ground—water inflow is present along the Colorado
Tailings, although its flow contribution is half that of the previous one.
This inflow contributes significant loads of copper, zinc, iron, arsenic,
and cadmium to Silver Bow Creek and also must be ground water with high
concentrations of contaminants.
Table 9 briefly describes the major surface water contaminant sources and
Table 10 de ibes ground—water contaminant sources.
Federal drinking water standards were exceeded for most parameters at
several wells sampled in the RI study area (Table 11). Concentrations
exceedences were measured for arsenic, cadmium, copper, iron, lead, zinc,
and sulfate.
-27—
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A 4
A total of 4,250,000 cubic years of mixed tailings, mine waste rock,
natural sediments, and precipitates were estimated to occur along Silver
Bow Creek from Butte to Warm Springs and along the upper Clark Fork River
from Warm Springs to Deer Lodge, Montana. Over 1,100 acres of visible
vaste deposits were mapped during the preliminary Silver Bow Creek Remedial
Investigation (SBC RI) studies.
Acid Mine Vaters
Mine waste water was discharged Into Silver Bow Creek beginning in the
early 1880’s. From the 1880’s until the early 1900’s water pumping systens
were operated at virtually every mine in Butte to remove mineral—laden
water from mines. In 1912, it was estimated that 4,000—5,000 gpm was
pumped from the Butte mines.
In 1889 the Anaconda Company began precipitating copper out of the mine
waste vater and continued this operation into the 1970’s. Throughout this
period, mineral—laden water was discharged from precipitation plants into
Silver Bow Creek. Water quality data characteristics of the chemical
composition of mine waste water during this period is not readily
available. Chemical characteristics of mine vater and precipitation plant
spent leach solution discharged into Silver Bow Creek in 1972 is shown in
Table 6.
Timber Treatment Sites
The Anaconda..1p t Treatment Facility (pickling plant) near Rocker (see Map
3) treated mine timbers with a preservative containing arsenic. Waste
material from the pressure treatment was dumped along the banks of Silver
Bow Creek. This facility operated at Rocker from the early 1900’s until
1956. Also, creosote vas used at this plant to treat poles and to
lubricate the skids for mine timber loading and unloading. Surface soils
at this facility had very high levels of arsenic. This site is currently
—18-
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SILVER BOW/BUTTE
SITE PROFILE
Document * 983—TS1-RT—ETTR
A. SITE OPERATIONS
A.1 PRODUCTS — Gold, Silver, Copper, Lead, Manganese
A.2 SITE OPERATION A.3 PROCESSES
Products Process Time Period
Gold/Silver, Lead/Silver Mining 1864 — Present
Copper/zinc/manganese
Copper/Silver Milling 1866 — 1910
Separation/concentration
Jigging
Flotation
Heap Roasting
Stall Roasting
Hearth Roasting
Gold/Silver/Copper Smelting 1866 — 1910
Copper/Zinc Blast Furnace
Reverberatory
Pyritic
Waste Management Practices:
• Direct dumping of mining, milling, and smelting vastes into
Silver Boy Creek (1870’s - 1972)
—1—
I ’
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Streamside Tailings Impacts
Erosion of streamside tailings deposits were not evaluated per se during
the RI. Instead, sediment entrainment was quantified, vhich represents
both bank erosion and channel sediment re—entrainment. Distinguishing
between the two processes is not possible vith existing data.
Surface vater data indicate contributions of channel or bank material
during higher flows to be significant along Silver Bow Creek from the
Colorado Tailings to Silver Bow and from Ransay Flats to Fairmont Hot
Springs. In both these reaches, increases in solid—phase metals (copper,
zinc, iron, arsenic, and lead) during high flows are consistent. This
probably represents previously deposited metals (including those
precipitated from discharge of mineral-laden mine waste vater) that are
remobilized during higher flows and the lack of extremely high flows during
the RI probably prevented significant bank erosion from occurring in the
study area.
Table 12 summarizes metal loads contributed in both stretches, some of
which are probably from stream bank tailings. The Surface Water and Point
Source Investigation (Appendix A of RI, MultiTech, 1987) found both ground
water and channel sediments to be major sources of vater quality
degradation in Silver Bow Creek. Impacts of ground—water inflow were
especially severe; impacts of bank entrainment could not be specifically
evaluated.
Other Impacts
For the protection of aquatic life, the concentrations of total recoverable
arsenic, cadmium, copper, lead, and zinc in natural waters should not
exceed specific criteria. Table 13 shows the number of times the USEPA
one—hour or Montana Department of Health and Environmental Sciences
criteria were exceeded at each surface water station sampled during the SBC
—33—
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RI. For comparison, the number of measurements of a contaminant are also
indicated.
Tables 14 and 15 show the number of water samples exceeding the primary and
secondary standards for drinking water at each of the surface and
ground—water sampling sites. Also shown in these tables are the number of
measurements at each site for total arsenic, cadmium, copper, iron, lead,
and zinc.
Algae
Water quality and algal sampling conducted during the Silver Bow Creek
Remedial Investigation (Multitech, 1987) provided limited evidence that the
algal communities in the Warm Springs Ponds have shown some metal uptake
(Table 16). Algal communities situated between the confluence of Silver
Bow and Blacktail Creeks and the Warm Springs Ponds have been slowly
recovering over the past ten years.
Riparian Vegetation
The riparian communities associated with the Silver Boy Creek and the upper
Clark Fork River have been significant receptors of waste and contaminants
transported by the Silver Bow Creek and the upper Clark Fork river.
Approximately 11,000 acres of riparian community areas have been inundated
by waste materials which do not support vegetative growth. Additional
areas have been affected by contaminant migration.
Agricultural Soils and Crops
The Agriculture Investigation provided circumstantial evidence that
approximately 5,400 acres of land have been contaminated by heavy metals to
varying degrees of severity, by using Silver Bow Creek or Upper Clark Fork
river water for irrigation. During the Phase One (reconnaissance level)
investigation, 38 soil horizon and 18 plant samples were acquired at 16
-37-
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Creek as far downstream as Miles Crossing; pollution stress apparently
resulted also In depauperate communities as far dovnstream as east of
Opportunity. Since then, more tolerant forms have begun recolonizing this
stream reach. However, the degree of annual fluctuation in both organism
density and biomass levels, as veil as generally by diversity, indicate
early stages of biological recovery.
High density arid biomass levels, but low diversity communities, or organic
matter—tolerant caddis flies plus Dipterans exist immediately downstream
from the Warm Springs Ponds discharge into the Clark Fork River.
Fisheries
The RI provided evidence that fish, particularly rainbow trout, are
receptors of heavy metal contaminants present within and downstream of the
study area (Table 17). Arsenic concentrations in all tissues tested were
below USDA food standards.
Measurable concentrations of PCP and PCB were found in the tissues tested
(Tables 18 and 19).
Waterfowl
The Waterfowl Investigation provides evidence that, at least cadmium is
accumulating in waterfowl residing in the wildlife management area of the
Warm Springs Ponds. Analytical results indicate that only cadmium was
significant 1 y i 1 evated above background levels in liver tissue, but not in
muscle tissue. None of the other trace elements were found to exceed
background levels in either tissue type (Table 20).
PCP was detected in muscle and particularly in liver tissues. The
concentrations measured do not appear to represent a significant public
health concern. Three of the four muscle tissues from wildlife ponds’
-46-
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have developed on alluvial fans and pediments (U.S. Soil Conservation
Service 1973). In the valleys, gently sloping, deep soils have developed
along terraces. Adjacent to Silver Bow Creek and the Clark Fork River,
shallow, gravel-textured to deep, fine—grained alluvial soils have
developed. Nutrient rich, organic soils of various depths are present in
some low and vetland areas.
Much of the natural soil in the study area has been affected by mining
wastes. Many soils along Silver Bow Creek and the Clark Fork River
floodplain are covered with waste materials which may contain a seasonally
fluctuating water table.
These mining-related wastes are generally sandy textured, reflecting their
granitic origin, and typically have high concentrations of metals and
sulfide minerals. The oxidation of sulfide minerals produces acidic
conditions that increase the solubility of many metals. Accumulation of
bio-availab].e heavy metals severely limits vegetation establishment, which
in turn limits soil development.
Pathways
Groundwater containing various dissolved and suspended pollutants were
produced from the characterized and potential waste sources by surface
water infiltrating downward through the sources, and/or by non—contaminated
ground-water contacting the sources. Once entrained in the aquifer, the
pollutants were distributed to other components of the site ecosystem by
discharge to- rface water and by beneficial water use (primarily
irrigation) withdrawal from the aquifer.
Groundwater efficiency as a pathway was determined by site—specific
factors. The physiochemical properties and concentrations of the
contaminants were affected by the nature of the source, reactions occurring
within the ground water, and aquifer ground-water interactions as they
migrated away from the source. Contaminant plume distribution was affected
-54—
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A l
Mining Waste NPL Site Summary Report
Silver Mountain Mine
Loomis, Washington
U.S. Environmental Protection Agency
Office of Solid Waste
June 21, 1991
FINAL DRAFT
Prepared by:
Science Applications International Corporation
Environmental and Health Sciences Group
7600-A Leesburg Pike
Falls Church, Virginia 22043
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4 J
DISCLAIMER AND ACKNOWLEDGEMENTS
The mention of company or product names is not to be considered an
endorsement by the U.S. Government or by the U.S. Environmental
Protection Agency (EPA). This document was prepared by Science
Applications International Corporation (SAIC) in partial fulfillment of
EPA Contract Number 68-W0-0025, Work Assignment Number 20.
A previous draft of this report was reviewed by Neil Thompson of
EPA Region X [ (206) 553-17771FTS 399-1777], the Remedial Project
Manager for the site, whose comments have been incorporated into the
report.
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Mining Waste NPL Site Summary Report
SILVER MOUNTAIN MINE
LOOMIS, WASHINGTON
INTRODUCTION
The Site Summary Report for the Silver Mountain Mine is one of a series of reports on mining sites
on the National Priorities List (NPL). The reports have been prepared to support EPA’s mining
program activities. In general, these reports summarize types of environmental damages and
associated mining waste management practices at sites on (or proposed for) the NPL as of February
11, 1991 (56 Federal Register 5598). This summary report is based on information obtained from
EPA files and reports and on a review of the summary by the EPA Region X Remedial Project
Manager for the site, Neil Thompson.
SITE OVERVIEW
The Silver Mountain Mine is an inactive precious metal heap leaching site, which covers
approximately S acres in a remote area of northern central Washington State. In 1980 and 1981,
previously mined materials (approximately 5,300 tons of ore) were piled on top of a plastic liner and
treated with sodium cyanide and caustic soda in an attempt to leach and recover gold and silver.
Leachate flowed from the leach heap through a lined ditch to a plastic lined basin. Activated carbon
at the site was possibly intended for use to remove the metal cyanides from the leachate.
Approximately 4,400 pounds of sodium cyanide was used to treat the tailings pile (leach heap). The
site was abandoned in 1981 without removal of any chemicals or treatment of cyanide leaching
solution.
Arsenic, antimony, and cyanide are the primary contaminants of concern. Population near the site is
relatively sparse, with less than 20 people within a 3-mile radius served by drinking water wells. The
land closest to the site is used for cattle grazing. The closest domestic water well is located
approximately 3 miles south of the site.
The Washington Department of Ecology conducted three remedial actions at the site, the last
occurring in 1985. In addition, in 1988 the Bureau of Mines closed and sealed a shallow well at the
site. A Record of Decision (ROD) describing the remedy at the site, selected in accordance with the
Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), has been
signed by the Region X Administrator and verbally concurred on by the State of Washington. This
ROD estimates the present value of costs of future remedial actions, assuming a 30-year period for
1
/11
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Silver Mountain Mine
site activities, to be $635,600. Currently, EPA is nearing completion of the technical design phase of
the remedial action. The timing of construction will depend on fund financing.
OPERATING H1S1 ORY
Underground mining for silver, gold, and copper began at the site in 1902. EPA’s Remedial
Investigation Report states that the mine was active in 1936, 1943, 1945, and 1956, and that by 1956
the mine had approximately 2,000 feet of underground mine workings and a few thousand tons of
mine dump. A mill was built in 1952 but may have never been used. No other records of
production were found. From late 1980 to late in the summer of 1981, Precious Metals Extraction
(PME), Ltd., constructed and operated the leaching operation described above (Reference 1,
Executive Summary, page 1, and Chapter 1, page 5). This operation was abandoned in 1981 with no
site closure or clean-up of contaminated material (Reference 1, Chapter 1, page 7).
Detailed records on the process used by PME and the construction of the leach heap and leachate
collection pond were not available to EPA during its Remedial Investigation. However, field
observations and data collected by the Bureau of Mines during its investigation in 1989 provided basic
information on the leaching process and unit construction (Reference 1, Chapter 1, pages 5 through
7).
“PME cleared an area of approximately 180 feet by 140 feet, adjacent to existing mine dumps. A
leach pad base of sandy soil up to 3 feet thick and graded with a 2.5 percent slope to the southwest
was prepared. At the southern end of the leach pad a rectangular trench 7 feet by 75 feet and
averaging 4 feet in depth was dug as a Leachate collection pond. The soil base and pond were then
covered with a green 20-mil thick plastic liner. Another layer of sandy soil, from 0 to 6 inches thick
was then placed over the plastic liner. Last, approximately 5,300 tons of material from the mine
dump were loaded onto the pad. The prepared heap was approximately 100 feet long, 105 feet wide,
and 14 feet high” (Reference 1, Chapter 1, page 6). As stated above, several tons of caustic soda and
lime, and approximately 8,000 pounds of sodium cyanide were combined with water and applied to
the leach heap (Reference 2, page 1; Reference 3, page 1).
Processing of the leachate to remove the precious metals may have been accomplished through direct
electroplating or by using activated carbon. Information on the type processing is not conclusive,
however containers of activated carbon were found onsite. The operation was abandoned in the late
summer of 1981 without neutralizing the solution in the leachate pond or materials in the leach heap.
Empty cyanide drums and large containers of activated carbon also remained onsite (Reference 1,
Chapter 1, page 6; Reference 3, page 1).
A)
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Mining Waste NPL Site Summary Report
SITE CHARACTERIZATION
EPA conducted a Remedial Investigation, completed in January 1990, to determine the environmental
characteristics and the type and extent of contamination. EPA found four potential sources of
contaminants (the leach heap, mine dump, mine drainage, and bedrock) and four potential exposure
pathways (onsite soils, onsite surface water, onsite ground water in a shallow aquifer, and offsite
ground water in the Horse Springs Coulee-Aeneas Lake aquifer.) The contaminants of concern have
been identified as arsenic, cyanide, and antimony (Reference 1, Executive Summary, page 2;
Reference 4, page 9).
Samples taken during EPA’s Remedial Investigation show levels of arsenic at moderate to high
concentrations in both the mine dump and the leach heap, the three highest values being 652
milligrams per kilogram (mg/kg) at the toe of the heap, 626 mg/kg at the top of the heap, and 1,075
mg/kg in the mine dump. Cyanide levels in the heap reach 173 mg/kg and appear to concentrate at
the toe of the heap with values of 10 times those occurring elsewhere in the heap (Reference 1,
Chapter 4, pages 2 through 5).
Arsenic, antimony, lead, other metals, and cyanide are contaminants at lower levels in the shallow
soils under the leachate pond and in soils adjacent to the leach heap (Reference 1, Executive
Summary, page 2 and Chapter 4, pages 2 through 5).
Ground Water
Ground-water monitoring was conducted during May, June, and July 1989. Onsite concentrations of
ground-water contaminants were compared to concentrations in downgradient water supply wells in
the Horse Springs Coulee Aquifer. Cyanide, as well as sodium, potassium, nitrate, nitrite, and
fluoride are contaminants that originate at the leach heap. Contaminants that originate in the mine
dump include arsenic, antimony, barium, chromium, copper, chloride, iron, lead, manganese, nickel,
silver, and zinc. In addition, arsenic and antimony occur in mine drainage and originate in the
bedrock of the mine workings (Reference 1, Executive Summary, page 2 and Chapter 4, pages 13
through 33).
Ground-water contaminants from the leach heap extend in a plume at least as far downgradient as the
furthest monitoring well (Well 3), 50 feet southeast of the heap. However, the Remedial
Investigation Report concluded that as of 1989 ground-water contaminants do not influence the nearest
4 -
3
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Silver Mountain Mine
offsite water supply wells 2 to 4 miles downgradient to the southeast of the site (Reference 1,
Executive Summary, page 3 and Chapter 4, pages 13 through 33).
Fate and Transport of Cyanide
According to EPA’s Remedial Investigation, the future impact of cyanide on ground and surface water
is primarily controlled by the amount and form of cyanide remaining in the leach heap, and by
seepage and degradation rates. These factors indicate that the cyanide concentrations occurring in
ground water during 1989 probably originated in spillage or leachate pond overflow at the time of
leach heap operations in 1980 and 1981. The Remedial Investigation estimates that, as a result of
remedial actions, little or no leachate has been produced since the heap was covered in 1985.
However, according to the Remedial Investigation, with time and deterioration of the plastic liners,
leaching of cyanide from the heap would be expected to resume with transport of cyanide to ground
water. Infiltration of cyanide is projected to occur at progressively reduced concentrations and rates
as a result of degradation, including speciation to hydrogen cyanide and subsequent volatilization.
Projected maximum concentrations of cyanide in leachate are on the order of a few milligrams per
liter (mgIl). Infiltration of leachate at these concentrations is projected to decrease to significantly
lower levels during passage through the unsaturated zone (Reference 1, Executive Summary, pages 2
and 3).
Fate and Transport of Arsenic
The future impact of arsenic on ground and surface water is primarily controlled by the amount and
form of arsenic in mined materials, the amount and form of arsenic in bedrock, and the sorption
capacity of iron- and aluminum-rich soils, according to the Remedial Investigation. These factors
indicate that, as the materials in the heap and dump oxidize, leachate from the leach heap and mine
dump could produce high concentrations of arsenic, on the order of a few tens of mg/l. The
Remedial Investigation concluded that with time and the anticipated decrease in sorption capacity of
the soils, arsenic concentrations impacting ground water could reach the same level as those in the
infiltrating leachate. In 1989, levels of arsenic in ground water indicated that oxidation of the mine
dump and buried bedrock has not yet progressed to the point of producing highly concentrated
leachate. Elevated levels of arsenic in mine drainage in 1989, however, indicated that oxidation may
now be taking place in the mine workings. Consequently, according to the Remedial Investigation, a
potential exists for arsenic concentrations to increase in leachate from the mine or any of the mined
material continually exposed to the oxidizing influences of weathering or water infiltration (Reference
1, Executive Summary, page 3).
4
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Mining Waste NPL Site Summary Report
ENVIRONMENTAL DAMAGES AND RISKS
Initial interest in the site was created in 1981, when the owner of the land’s surface rights informed
the Okanogan County Health Department of the heap leaching operation (Reference 1, Chapter 1,
page 7; Reference 5). Originally, the Washington Department of Ecology responded to the threat
caused by the cyanide in the leachate collection basm. Upon further investigation, EPA found
additional potential sources of contaminants (the leach heap, mine dump, mine drainage, and
bedrock), and additional contaminants of concern (arsenic and antimony, as well as cyanide)
(Reference 1, Executive Summary, pages 1 and 2; Reference 4, page 9).
The Remedial Investigation, completed in January 1990, presented a human health risk assessment for
the site. The risk assessment identified arsenic, antimony, and cyanide as the contaminants of
concern at the site. Population near the site is sparse, with less than 20 people within a 3-mile radius
served by drinking water wells. The land closest to the site is used for cattle grazing. The closest
domestic water well is located approximately 3 miles south of the site Currently, the closest
livestock watering well is located 2 miles from the site. Other concerns include use of the site by
local teenagers who may potentially become exposed to the contaminants (Reference 1, Chapter 6,
pages 12 and 13; Reference 3, page 1; Reference 4, page 10).
Arsenic, antimony, and cyanide are the most important contaminants in water. Based on future
exposure scenarios, exposure to arsenic in water could result in an increase in cancer risk of 2 x 10’.
There is also risk of noncarcinogemc effects from arsenic, cyanide, and other chemicals (Reference 1,
Executive Summary, page 4).
The most important contaminant in soil is arsenic. Based on future exposure scenarios, exposure to
soil could result in an increased cancer risk of 2 x i0 , as well as noncarcinogenic effects (Reference
1, Executive Summary, page 4).
REMEDIAL ACTIONS AND costs
The Washington Department of Ecology conducted three remedial actions at the site, the last
occurring in 1985. In addition, in 1988 the Bureau of Mines closed and sealed a shallow well at the
site.
The site was included on the NPL in October 1984. A ROD describing the final EPA remedy at the
site has been signed by the Region X Administrator and verbally concurred on by the State of
Washington. Each of these actions, as well as available cost data, are described below.
s
f t 1
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Silver Mountain Mine
On November 19, 1981, the Washington Department of Ecology treated the leachate in the trench
with approximately 600 pounds of chlorine (calcium hypochlorite), which converted the cyanide to
carbon and nitrogen. The neutralized solution was then pumped into a County water truck and
sprinkled over a wide area (Reference 1, Chapter 1, pages 8 and 9; Reference 6). A second attempt
to neutralize leachate collected in the basin was made by Washington Department of Ecology in
December 1982. However, concentrations continued to increase after neutralization due to continued
leaching from the mine tailings. The cost of the first neutralization, in 1981, was approximately $930
for chlorine and gasoline (Reference 1, Chapter 1, page 8; Reference 3, page 5; Reference 6).
In June 1985, the Washington Department of Ecology stabilized the site by removing liquids and
residue from the leachate pond, and covering the leaching heap and pond with geotextile fabric and a
33-mu hypalon liner (Reference 1, Chapter 1, page 9).
In November 1988, the Bureau of Mines permanently closed the shallow well located 75 feet south of
the leach heap. The well was viewed as a potential conduit for contaminants to enter the aquifer.
The well was sealed by filling it with bentonite and capping it with a concretefbentonite mixture
(Reference 1, Chapter 1, page 9).
The remedial actions presented in the ROD consist of the following (Reference 4, page 2):
• Consolidating and grading approximately 5,740 cubic yards of contaminated materials.
• Covering the materials with a soil/clay cap.
• Fencing the site and sealing the underground mine entrance.
• Disconnecting the mine drainage pipe from the existing stock tank and installing a new well in
Horse Springs Coulee aquifer to provide an alternative water supply for the cattle.
• Placing a deed restriction to protect the cap.
• Monitoring the ground water to assure that it does not become contaminated. If ground-water
analyses indicate contamination at a concentration in excess of EPA health-based levels, a
contingent ground-water treatment program will be implemented. Notice will be provided to
the community of the ground-water sampling and results and any potential contamination.
The estimated capital cost of the above remedial action is $370,360 and the annual operating and
maintenance costs are $39,650. The present value, assuming a 30-year period for site activities, is
6
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Mining Waste NPL Site Summary Report
$635,600 (Reference 4, page 25). More specific cost estimates are provided in the Feasibility Study
Report.
According to the Remedial Project Manager for the site, these costs will be revised after final design.
Estimates are now closer to $700,000 just for the construction of the cap. The State will be in charge
of periodic monitoring.
CURRENT STATUS
According to the Remedial Project Manager for the site, EPA is nearing completion of the remedial
action design. The design addresses all activities identified in the ROD, from consolidating and
capping contaminated materials to monitoring the ground water. Because it is a fund-lead site, timing
of the construction depends on fund financing. Once financed, the construction can be completed in a
single construction season (Reference 7).
-
7
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Silver Mountain Mine
REFERENCES
1. Remedial Investigation Report, Silver Mountain Mine; EPA Region X; January 19, 1990.
2. Letter Concerning Cyanide Contamination at the Silver Star Mine; From Patrick D. Ewing,
Chemist, Precious Metals Extraction, Ltd., to Dennis Bowhay, Washington Department of
Ecology; August 20, 1982.
3. Potential Hazardous Wastes Site: Preliminary Assessment, Silver Mountain Mine, Washington;
Washington Department of Ecology; Undated.
4. Record of Decision for the Silver Mountain Mine Superfund Site; Thomas P. Dunne, Acting
Regional Administrator, EPA Region X; March 27, 1990.
5. Notes Concerning Damage Report and Mineral Rights; Dennis Bowhay, Washington Department
of Ecology; July 21, 1983.
6. Memorandum Concerning Neutralization of Silver Mountain Cyanide; From Harold Porath,
Washington Department of Ecology, to John Hodgson, Washington Department of Ecology;
November 19, 1981.
7. Telephone Communication Concerning the Current Status of the Silver Mountain Site; From
Ingrid Rosencrantz, SAIC, to Neil Thompson, EPA Region X Remedial Project Manager; August
9, 1990.
8
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Mining Waste NPL Site Summary Report
BIBLIOGRAPHY
Bowhay, Dennis (Washington Department of Ecology). Notes Concerning Damage Report and
Mineral Rights. July 21, 1983.
DeNike, Ed (Washington Department of Ecology). Notes Concerning Cyanide Neutralization.
January 28, 1982.
Dunne, Thomas P. (Acting Regional Administrator, EPA Region X). Record of Decision for the
Silver Mountain Mine Superfund Site. March 27, 1990.
EPA Region X. Feasibility Study Report, Silver Mountain Mine. January 17, 1990.
EPA Region X. Remedial investigation Report, Silver Mountain Mine. January 19, 1990.
Ewing, Patrick D. (Chemist, Precious Metals Extraction, Ltd.). Letter Concerning Cyanide
Contamination at the Silver Star Mine, to Dennis Bowhay, Washington Department of Ecology.
August 20, 1982.
Gallagher, Michael J. (Washington Department of Ecology). Memorandum Concerning Onsite
Inspection of the Silver Mine Site, Loomis, Okanogan County, By Ecology and Environment
Inc., on September 4, 1984, to File. September 17, 1984.
Nelson, Barry (Okanogan County Health Department). Motion and Affidavit for Order to Enter
Private Property and Abate Public NuisancelHealth Hazard, Superior Court of the State of
Washington. November 13, 1981.
Porath, Harold (Washington Department of Ecology). Memorandum Concerning Neutralization of
Silver Mountain Cyanide, to John Hodgson, Washington Department of Ecology. November 19,
1981.
Russell, Robert H. and Eddy, Paul A. (Washington Department of Ecology). Geohydrologic
Evaluation of Aeneas Lake-Horse Springs Coulee, Okanogan County, Washington. January 1972.
Superior Court of the State of Washington. Order for Entry and Abatement of A Health Hazard.
November 13, 1981.
Washington Department of Ecology. Potential Hazardous Waste Site: Site Inspection Report, Silver
Mountain Mine, Washington. August 13, 1982.
Washington Department of Ecology. Potential Hazardous Wastes Site: Preliminary Assessment,
Silver Mountain Mine, Washington. Undated.
Weston, Donald. Hazard Ranking System Score Sheet and Documentation for the Silver Mountain
Mine. April 17, 1984.
9
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Silver Mountain Mine
Weston, Donald. Telephone Communication Concerning Silver Mountain Mine to Barry Nelson,
Okanogan County Health Department. April 13, 1984.
10
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tl ,
Silver Mountain Mine Mining Waste NPL Site Summary Report
Reference 1
Excerpts From Remedial Investigation Report,
Silver Mountain Mine; EPA Region X;
January 19, 1990
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REMEDIAL INVESTIGATION REPORT
SILVER MOUNTAIN MINE
OKANOGAN COUNTY, WASHINGTON
January 19, 1990
U • S. !nviron snta1 Prot.ction Aq.ncy
R.gion 10
S.attl., Waahington
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EXt CUTIVE SUMMARY
The Silver Mountain Mine site comprises about five acres in
Okanogan County, Washington, which have been contaminated with
mining wastes containing cyanide, arsenic and other metals. The
mine site is six miles northwest of Tonasket along the west
margin of Horse Springs Coulee, a north—south trending valley.
Horse Springá Coul.. contains as much as 150 feet of
unconsolidated glacial drift and alluvium overlying
metasedimentary bedrock. Unconsolidated sediments thin toward
the valley wall in th. area of the mine site. Th. region is
semi—arid with scrub vegetation and is used primarily for cattle
grazing.
Underground mining for silver, gold, and copper production
began at the site in 1902. Mining occurred in silicified zones
of disseminated eulfides in the bedrock. By 1956, sporadic
development produced about 2000 feet of underground mine workings
and a few thousand tens of mine dump consisting of waste and
mineralized rock. A 400-ten per day mill was constructed in
1952, but nay never have been used. The mill has since been
removed.
From 1980 t 1981, Precious Metal. Extraction, Ltd.,
constructed and operated a cyanide leach heap of previously mined
material in an attempt to extract silver and geld. Th . heap
consisted of about 5300 ton. of or. in a 100 X 105 X 14 foot pile
on top of a 20-nil plastic liner. About 4400 pounds of sodium
cyanide was mixed with water and sprayed on the top of the heap.
Th, cyanide—laden effluent was then collected in a leachats pond
at the base of ths h.ap. The leach heap operation was abandoned
in. 1981 without cleanup of contaminated material.
The Washington Department of Ecology investigated the site
in 1981 and in 1982 used sodium hypochiorit. to neutralize the
leachate pond and heap. Th. U.S. Environmental Protection Agency
conducted a Preliminary Assessment and Sits Inspection in 1984.
The sits was added to the National Priority List of Superfund
sites in 1984. In 1915, the Department of Ecology conducted a
sits stabilization effort which included removal of liquids from
the leachate pond and installation of a 33-nil plastic cover over
the heap and pond to reduc. infiltration. pty cyanide drums
were also removed, a fenc. was installed, and the site was
posted. A Remsdta.t Investigation and Feasibility study under an
Interagency Agreement with the U.S. Bureau of Kin .. wa, commenced
by EPA in 1988.
Th• physical and chemical characteristics of the site and
the nature and extent of contamination were evaluated b field
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RI EXECUTIVE SUMMARY
PAGE 2
geologic napping, hydrogeologjcal investigation, and chemical and
petrographic analysis of site materials. The hydrogeological
investigation incorporated four monitoring wells and three
offsite water supply wells, and two surfac, water sites. Thirty-
four samples of leach heap and mine dump material, twenty samples
of nearby soils, and three rounds of water samples from the seven
wells and two surface water sites wer. collected and analyzed.
The investigation identified and evaluated four potential sources
of contaminants: the leach heap, nine dump, mine drainage, and
bedrock. Potential exposure pathways for contaminants were
identified as onsite soils, onsite surface water, onsite ground
water in a shallow aquifer, and of fsite ground water in the Morse
Springs Coules’Asneas Lake aquifer.
Elevated levels of contaminants in solid material are
largely confined to mined bedrock that has been crushed through
the process of mining. The mined material has been either
abandoned in unleachad piles (mine dump).. or abandoned after
leaching with cyanid. solutions (leach heap). Relative to
background soils, levels of arsenic, antimony, lead, and other
metals and aetalloids . are elevated in th mm. dump, and these
same constituents plus cyanid. are elevated in th. leach heap.
The sass contaminants occur at lower, but still elevated,
concentrations in shaXloi. soils beneath the heap lsachat.
collection poz4 z4 in a localized area o& shallow soil, within 25
feet adjacent to the heap.
Onsits concentrations of ground water contaminants were
compared to concentration. in downgradi.nt water supply wells in
the Morse Spring. Coul.. aquifer.. Contaminants which originated
at the leacb heap and which wars elevated in onsit. ground water
included cyanide, and slightly levated levels of sodium,
potassium njtrat.F nitrit, and fluoride.. Elevated contaminants
which originated either at b.droc or at the mine dump included
arsenic.. anti.aonT ,,. barium, chrenium, copper, chlorid•, iron,
lead., ___ nickel, silver, and zinc. In addition, elevated
arsenic and antta? occur in sine drainag, and originate in the
mine workings, is. bsdrcck.
Ground water contaminants f run the leach heap extend in a
pl at leaa as. far downgradisnt as the furthest monitoring
well, Well 3. 50 f..t southeast of the heap. Ground water
contaminants fr either the mine dump or bedrock are
substantially reduced at W.11 3, which is lOO 2OO feet
dovngradi.nt of then. potential sources. No ground water
contaminants influence the nearest offsits water supply wells 2-4
miles doimgradi.nt to the southeast of the sine site.
The future impact of cyanide on ground and surface water is
primarily controlled b the amount and form of cyanide remaining
in ths heap, and by seepag. and d.gradatioft rates. Measurements
,
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RI EXECUTIVE SUMMARy
PAGE 3
of total and weak acid dissociab]. , cyanide indicat, that the
Cyanid, in heap material is mostly in the form of poorly Soluble
iron Cyanids compounds. The estimated degradation and seepage
rates for cyanide indicate that the levels now occurring in
ground water probably originated in spillage or leachat, pond
overflow at the time of leach heap operationa during 1980 and
1981. Probably little, if any, leachat, has been produced since
the heap was covered in 1985. However, with time and
deterioration of the plastic top and bottom liners, leaching of
cyanids from the heap would be expected to resume vith transport
of cyanide to ground water. Infiltration of cyanid, is projected
to occur at Progressively reduced concentrations and rates as a
result of degradation, including speciation to hydrogen cyanide
(HCN) and subsequent volatilization. Projected maximum
concentration, of cyanide in leachat. are on the order of a few
mil ligrw per liter. Infiltration of leechat. at these
concentrations is projected to degrad. to significantly lower
levels during passage through the unsatur t, zone.
The future impact of arsenic on ground and surface water is
primarily controlled by the amount and form of arsenic in all
mined materials, including the heap and sin, dump, by the amount
and form of arsenic in bedrock, and by the sorption capacity of
iron- and aluminum-rich soils. The estimated salubility of
ars.njc and sorption capacity of soils indicate that, as the
surf icial piles oxidize, leachat. from the heap and the mine dump
could produce high concentrations of arsenic on th• order of a
few tens of milligram. per liter. Retazdatj of initially high
concefltr j y. of arsenic in leachat. could occur during
infiltration. However, with time and saturation of sorption
sites, arsenic level, impacting ground water could reach the same
levels of arsenic aw infiltrating leachat.. Current levels of
arsenic in’ ground water indicat, that oxidatjo of the sine dump
and buried bedrock has not yet progressed to the paint of
producing highly concentrated- leachat.. Current elevated levels
of arsenic in sin, drainage, however, ind.tcat. that oxidation may
now be taking place i the ain* workinge. Conseque tly, a
potential exist, for arsenic concsntratjo to increase in
leachat. from any of the mined material continually exposed to
the oxidtzi influence. of vsatherthq or Water infiltration.
At prs..,t, water supply well, in the main part of Horse
Spring. Coul. aquifer ar, not affected by contaminated ground
water from the mine sit.. The projected impact from estimated
futur, levels of cont j t, is significantly less in the
Horse Springs Coulee aquifer than in the shallow aquifer at the
sin, site becaus, of dilution resulting from a larg. contrast in
ground water flow between the two areas.
The human health risk from cyanide, arsenic, and other
contaminar t. is based on the likely future use of the site.
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RI EXECUTIVE STJ)*(ARY
PAGE 5
time, vegetation, wildlife, and other biota could potentially be
exposed to toxic concentrations of metals in pond.d heap leachate
or in heap soils. Soils fl the heap and dump are most likely to
be toxic if they erode, spread out, leach, or are otherwise mad.
more availabl. to onsit. biota.
Air transport of particulate. from the tailings pile is
negligible under present conditions. Ground water is not toxic
to plants or aquatic biota at present. Surface water transport
is absent for most of th• year and the intermittent streams do
not feed the clos..t surface water bodies of concern. Transport
to the.. nearby sensitive couniti. . in Horse Springs Ceul..
dos not occur by either surfac. water or ground water discharge
from th. sit...
Although small in area, the soils nearby the heap and dump
are contaminated with arsenic, manganes., seleni , and zinc, at
concentrations that ca affect vegetation and animals. In
particular, ruminants - rabbits, rodent., and birds are at risk
when consuming vegetation, soil biots, and associated soil fro
these contaminated 50i1$e Manganes. and selenium concentrations.
ars- of concerm. threugh at the sit., including background areas.
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RI HA7 ER 1
PAGE 2
Based on information about the cyanide heap leaching
operation at the sit., an abandoned leach heap and adjacent mine
dump are considered to be sources of contamination. The Remedial
Investigation addresses potential contamination in th. leach
heap, the. mine dump, onsit. soils and surface water, and
underlying ground water. Potential releases of hazardous
materials tothe air are considered in the risk assessment
portion of the RI report.
1.2 SITR BACXG )lD
This section includes a brief description of th. site,
information about historical development an land use practices,
a sii ary of events leading to th. site’s inclusion on the NPL,
and a discussion of the results of previous investigations
1.2.1 Site Description-.,
The- Silver Mountain Mine sit, consists of five acres in
okanogan County, north-centra’ Washington (southwest quarter of
Section 34-, T3$W, R26$). The sits (Figure 1.3) is-six air miles.
northwest- of the town of Tonasiist. (population 1055) and. lies in a
north-south trend m c basin between a scarpion the vest and a low
ridge on the east- The valley- is pert-ofe larger north-south
running valley b’own as Hors. Spring. Coules.
The area surrounding the sit, is sen-i -arj3 vith. scrub,
vegetation and is used primarily for cattle grazing. From county
road 9410, an unpeve access road leadnL.5 miles to th• site,
which is surrounded. by a barbed-wire fenc ,
Of key interest- at th. sit, is a heap of mined material and
a trench remaining’ from an abndoned cyanide heap leaching
operation (Figure 1.2). These viii be r.f.rr.6 to as the leach
heap and leachats pond in this- report. Both th• heap and the
pond are presently covered with a scrin-rejnforc.d Hypalon liner,
to be referred to as the cover. Directly vest of the leach heap
is a larger pu. of unprocessed mined aat.rial,, which will be
referred te a. the mine dump.
The foundation, of a former mill building are about 250 feet
southwest of the heap. A mine entrance, or edit portal, is
located• approximately 200 feet west of the heap in the scarp, and
water from saturated mm. workings is piped from within the
portal to a cattle watering trough, or stock tank., outside the
fenced area. Approximately 75 feet south of the heap !as a
shaliov well, nov sealed and abandoned. A small, freshwater seep
northwest of the heap creates a small shallow pool of standing
water. A single tree provid.s shad• and seasonal greenery at the
site.
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RI HAPT 1
PAGE 6
metals ar. then recovered from the solution. The used solution
is typically adjusted for pH and cyanide content and is re—
applied to the top of th. ore heap until sufficient recovery of
the precious metals is mad.. Additional information on cyanide
heap leaching techniques is provided in Appendix A.
No historical records or company staff ar, available to
describe the process used during the development by Precious
Metals Extraction (PM!). Th• following scenario is based on
field observations and data collected by the Bureau in 1989. To
begin the heap Leaching process, PM! Cleared an area
approximately 180 feet by 140 feet, adjacent to existing mine
dumps. A leach pad bass of sandy soil, up to 3 feet thick and
graded with a 2.5 percent slops to the southwest, was then
prepared. At the southern end of the sloped pad base a
rectangular trench 7 feet by 75 f set and averaging 4 feet in
depth, was dug as a leachat. collection pond. The soil base and
pond were the covered with a green 20-sil thick plastic liner.
Another layer of sandy soil, from 0 to 6 incbu thick, was then
placed over the plastic liner. Last, approximately 5,300 tons of
material from th. mm. dump were loaded onto the pad. The
prepared heap was approximately 100 feet long, 105 feet wide, and
14 feet high.
Ecology and Environment (1985) report that during the months
PM! operated .hs heap leach, several tons of caustic soda and
lime- and approximately 4,400 pounds (20 55-gallon drums) of
granular sodium cyanide were combined with water and pumped over
the heaped material on the pad. After ths alkaline cyanide
solution percolated through the heap and drained into the
collection pond, the remaining processing sequenc. is unclear.
Ecology and Environment (1985) state that gold and silver were
slectroplat.d directly from the metals—laden leachats and that
the alkalinity and cyanide content of the leachat. were adjusted
before reapplication of th. solution to the heap. Woodward-Clyde
(1987)- report that activated carbon was used to remov. the silver
and gold from th leachat.. Direct electrovinning of leach
solutions is possible, but the two most commonly used methods for
removing gold and silver from alkalin, cyanide heap leach
solutions ax. Merrill-Crows zinc dust precipitation and activated
carbon adsorption. Photographs taken by the Department of
Ecology in July 1981 and 3uly 1982 (Appendix B) suggest that
solution was .d from the leachat pond into barrels of
activated carbon lined up next to the pond. Excess solution was
allowed to overflow the barrels onto a plastic liner and run back
into the pond. The photos also indicate that the carbon,
containing gold and silver, may have been pressure-stripped of
the precious metals on site.
Available information does not indicate whether an
additional tank or pond was used to adjust the alkalinity and
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RI CHAPTER 2.
PAGE 8
On November 13, 1981, the Superior Court of the Stat.
of Washington issued an order for Okanogan County
officials to enter the site and addr.s, potential
health hazards posed by the leachat, in the collection
pond and by discardect chemical and Processing
containers.
The owner of the property surfaca rights put temporary
fencing aroun4 the sits to prevent cattle from EXposure
to contaaj, ated pond liquids in 1981.
In Noveabez 1981, Department of Ecology sampling
indicated total cyanide. conc .ntra of 600 mg,/]. in
the leachat. pond arid <0.002 ag/i in the onsit. well.
Ecology neutralized leacbat. in the collection pond
with sodium hypocbjorit. (HTE which converts cyanide
to carbon and nitrogen. Free chlorjj was observed,
indicating that neutralizati was CO.upist*. Using a
water tanker-spray truck, Ecology spray.d the
neutrsij solution around ta. ains ares. AdditiOnal
IIT VU put into the trench to ne1*rali any leachat.
that might collect over the winter.
In Spring of 1982, Departaer of Ecology sampled the
winter. leechat. and found total cyanide values of 220
ag/i. Soil. where the neutralized liquids- had been
dispcs.o o in November’ i s v. , also sampled and
indicated 0.23 ag/kg tota.b cyanid. , J1T solids which
had settled in the pond were stirred up to activate
nUtz’aijzati
In Decesbem lSS 3 ’j the pond was again neutralized by the
Department of Ecology. Reportedly, the liquid was
circulated zpeat.aiy tbrough the h.a during
neutj j . 4 Over 5 hour., total Cyanide levels in
the pond dropped from - 19 ag/i to <0.007 ag/i. Small
amounts at liquid coming fro, tb. heap after the
proces ve measured at 30 mg/i total Cyanide. A soil
sampl. taken near the pond showed 100 ag/kg total
cyani4.. In November 1983, samples from the leachate
poa indicated that leaching by rain and snowmelt
througk the heap had brought total cyanide
conce tratj in the pond up to 9.2 ag/i.
In September’ of 1984, Ecology and Environment, Inc. (E
& B) conducted a preliminary sit. insp .cti.ri for EPA
and mad• reconsn4a jo for neutralizing cyanid, in
the leach heap. Leachats collection pond liquids, heap
soil, and onsite backgrouj soil were analyzed for
total cyanide and metals. B & B collected two water
and two soil samples far the Department of Ecology.
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RI CHAPrER 4
PAGE 2
to 561 mg/kg, copper to 546 mg/kg, lead to 267 mg/kg, barium to
110 mg/kg, nickel to 51 mg/kg, and silver to 39 mg/kg. Mercury
ranges from values below the detection limit of 0.02 ag/kg to
maximum concentrations of 0.36 mg/kg in the heap and 0.78 mg/kg
in the mine dump.
Cyanid . results are shown in Table 4.1 both as total cyanide
and as weak acid dissociable (WAD) cyanide. Total cyanide ranges
up to 173 mg/kg in the heap with a corresponding weak ac .d
disseciable cyanide value of 15.1 mg/kg.
Examination of Table 4.1 and Figure 4.1 indicates that
preferential concentration of cyanid. occurs at the toe of the
heap, with values about ten times those occurring elsewhere in
the heap. Additionally, a few other elements including sodium,
manganese, copper, zinc, and lead, ar . concentrated along with
cyanide at the to. of the heap, whereas chromium appears to be
depleted from the top of the heap.
Arsenic occurs at moderate to high concentrations in both
the mine dump arid the leach heap, as shown in Figure 4.2. The
three highest values of arsenic are 652 mg/kg at the toe of the
heap, 626 mg/kg on top of the heap and 1075 ag/kg in the mine
dump.
The rssultm of toxicity characteristic testing of eight
samples are 1ist .iu Table 4.2, four sample. as EP-Toxicity
(extraction procedure toxicity test) and four as TCLP (toxicity
characteristic leaching procedure). Th• P toxicity tests show
that heap aat.ria.1.does not .xcud inorganic leachate criteria
that would de.igi’sts the waste as hazardous waste under federal
RCRA reguLations (40 CYR Section 261) or dangerous waste under
Washington Stats Dangerous Wast. regulations (WAC 173-303).
Of the eight parameters analyzed in th. toxicity
characteristic tests, lead, cadmium, and barium appear to leach
from th. hasp material at concentrations greater than that found
in ground- water s les. Th teat procedures are performed under
acidic conditions and would indicate that these metal. should be
relatively higk in leachats if the heap were leached under acidic
conditions. Both the heap arid ground water are slightly
alkaline, howevr, and acidic leaching should not occur under
current conditions. Additional discussion of the leaching
characteristics of heap material with respect to cyanide and
arsenic is includd in apter 5.
t o
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R I CHAPTER 4
PAGE 4
A
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Figurs 4 • 2. Th* distribution of arsenic in the leach heap, am.
di , az soil. Siapi. locations irs nswbsred in figure
2 • 3a. Data irs in ag/kg. The two values not.d by arrows
are background .a les no. 53 and 54 • Values separated by
horizontal ho represent upper and lover saaplss at the
sane location.
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-------
RI cH PTER 4
PAGE 14
Cyanide analyses were made of samples collected after first
checking for the presence of interfering Constituents, including
sulf ides or oxidants, using the procedure discussed in Chapter 2.
cyanide samples were then preserved with sodium hydroxide. Anion
and cyanide results are listed in Tables 4.5 (Round 1), 4.6
(Round 2), and 4.8 (Round 3).
4.3.2.1 Onsits Ground Water
Th. field parameters (Table 3.3) and th. relative
proportions of the major dissolved constituents may b. used to
characterize the gen.ral compositional pattern in ground water.
Figure 4.3 displays a trilinear Piper diagram (after Piper, 1944)
of the proportions in milliequival.ntz of the major cations
(sodium, potassium, calcium, and magnesium) and anions (chloride,
sulfate, bicarbonate. and carbonate f or all of the Round 3
analyses (Tables 4 • 7 and.. 4.8). The Piper diagram, laboratory
analyses, and field parameters indicate that ens its ground water
is a neutral to slightly alkaline magnesium-sodium sulfate
solution with about 400-900 aq/L total. dissolved solids.
The major cation., in order of decreasing. concentration, are
sodium, magnesium, calcium, and potassium. Sa mpl.. from
Monitoring Well 3, at the sc.utheast corner of- ths leach heap,
showed the highest concentrations of major cation.. Samples from
Wells 1 and 4 were relatively high in iron and aluminum. The
highest values in Round 3 were obtained from Well 1 with 10.7
mg/L of iron and 9.3 ag/L of alumin ., Other dissolved
constituents measured at relatively high; concentrations in Round
3 samples include manganese at 270 jhq/1 and copper at 48 g/L in
Well 1, and antimony at 44 Mg/L in Well 2.
The major anion. in onsit. ground water, in order of
decreasing a dancs, are sulfate, bicarbonate, nitrate, and
chloride. The Piper diagram (Figure 4 • 3) indicates a somewhat
higher proportion of sulfate in onsit. ground water relative to
offsite water. ffcvsvr, no compositional trend comparable to
that for cation. i. apparent for the anion, shown in th. diagram.
In Round 3 the highest nitrate concentration occurred in
sampl from Well 3, at. 17 mq/L. Much greater concentrations of
nitrate 1 the highest at 120 ag/L, were found in Round 2 samples
fro* Wells. 1, 2, and 3. Round 2 values are qualified as
estimates, however, and neither the high concentrations nor the
distribution pattern of nitrate from Round 2 were verified in
Round 3 • Thus the nitrat. values from Round 3 are considered to
be the most representative.
For all thre, rounds, total cyanide concentrations are
,“
-------
RI CXApr 4
PAGE 15
Consistently highest in Well 3, with values ranging from 30
in Round 2 to 280 Mg/L in Round 3. Corresponding weak acid
dissocia.ble cyanide concentrations for Well 3 range from 3.1. to
92 Mg/L.
Two divergent distribution pattern.s of major constituents
and contaminants are apparent from the Round 3 data. An increase
in concentration of several parameters occurs in the downgradjent
direction as ground water passes beneath the heap. A
representative example of this pattern is the distribution of
cyanide, nitrate, and electrical conductivity sbmm in Figure
4.4. All are highest to the southeast in v.11 3 which is the
downgrsdient direction. This pattern is consistent with the
compositional trend for major cations shoving increasing
proportion of sodium and potassium in the dovngradient direction
from wells 1 and 2 to wells 3 az 4 (Figure 4.3). Other
parameters showing the sam, trend include fluoride and nitrite.
On the other hand, other parameterB show higher
concentrations in wells 1 and 2, which lie respectively
upgradient and marginal to the dovngradient direction from the
heap. Included in this set of parameters are arsenic, antimony,
barium, chloride, chromium, copper, iron, lead, manganese,
nickel, silver, and zinc. Ths concentrations of arsenic are
displayed in figure 4.4.
4.3.2.2 Onsits Surface Water
In contrast to the onsita ground water, both the seep and
the mine drainag. ax, slightly alkaline aagn siua sulfate
solutions (Tables 4 • 7, 4 • 8). As shown by the Piper diagram
(Figure 4 • 3), sodium and potassium occur in much lower
proportions in the surface water than in the ground water. With
the exception of arsenic, elevated levels of most constituents do
not occur in th. surface water. Although cyanid. was detected at
1.2 Mg/L in a Round- 2 sample of the mine drainage, it was below
detection limits in the other two rounds.
Arsenic, on the other hand, is higher in the mine drainage
than in any other water at this sit.. Dissolved arsenic
concentration in the mine drainage was 91 g/L in Round 3.
4.3.2.3 Offsite Ground and Surface Water
Samples from the three veils within three miles dovrtgradieflt
of the site indicate that ground water from the main portion of
the Hors Springs Coule—Aeneas Lake aquifer is a ca1cium
magnesium bicarbonate solution (Figure 4.3) varying from neutral
-------
RI CHAPTER 4
PAGE 16
to slightly alkaline. The of fsite ground water samples were
lower in the proportion of sodium, potassium, and sulfate in
comparison with ensite water. The offsit. water also had lower
concentrations of all other major constituents (Table 4.7, 4.3)
and did not contain elevated levels of contaminants. Overall,
water drawn at ths offsite wells appears to be of good quality.
The quality of offaite surface water was not investigated.
The closest discharge of water from the area of the mine site to
an offsite surface waber body is likely no closer than Aeneas
Lake, five miles to the southeast (Russell and Eddy, 1971). The
flow path would be from onsite, through the Horse Springs Cou].ee
aquifer, to Aeneas Lake. The three water supply wells examined
during the Remedial Investigation lie between the mine site and
the lake. The water quality in these wells is expected to be
more indicative of ground water directly upqradi.nt of any
discharge. to surface water (such. as Mn.a, Lake) than onsite
ground water. As noted above these wells hav, generally good
water quality. Therefore, onsite contaminants are unlikely to
extend at present t either offsite ground water or surface
water.
A;.
-------
RI iAP1’ER 4
PAGE 17
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RI CHAP1’ER 4
PAGE 18
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RI APX’KR 4
PAGE 19
Tabls 4.5. tsr M tyt$c.I ts jIts. lard 1 MI _ Cywdds.
Loc.t$ W 0C • C I F S a(tot.I) ( $;
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MoMtorIn W11 2 190515041 4.4 0.77 U 541 3.2 5
i toe1, i tI 3 890015043 5.4 0.12 U 779 40.2 5
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NanItorII *41 40 3.0 0.29 126
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lrr$89t*ou *11 2 8905150* 1.4 0.12 U 126 0.2 1
lIv .t. 890513049 0.26 0.05 U 1.7 0.2 1
iI , *. 190515000 0.17 0.00 U 6.3 0.2 I
lfrst 1 9051S19t 0.31 0.02 U 3.4 0.2 $
O4dzud *tor 1S052 0.10 0.11 U 1.3 0.2 I
Notouz 1. P Ct . 104 u .s 4,, .I I IIirltl Ioy Sf s.
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-------
RI CHAPTER 4
PAGE 20
Tabls 6.6. Wt1? AIIIIYIIC$I ii$UtI$. R t 2 CywI .
LoC.tiOfl WFCC I CL V N03 $06 C (Totat) C1( s )
Monitoring Will I 89060705! 6.4 J 0.26 121 j 156 . 0.80
R1I at. 890607056 0.15 J 0.03 U 0.1$ J 0.19 .1 0.40
Mon to ng Will 2 890607057 3.0 J 0.36 98.5 J 315 a 2.6
Rin.t• 890607055 0.14 J 0.03 U 0.16 UJ 0.19 a 0.80
onItorfns WiLL 3 890501059 3.1 J 0.54 42.5 J 682 .1 30.6 3.2
Monitoring Will 35 3.1
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RI AP ER 4
PAGE 21
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A)
RI cHAprER 4
PAGE 22
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-------
RI CHAPTER 4
PAGE 23
T 4s 4.1. tir A, tytIc.I Isgts. 4sl 3 MIsS
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-------
PELCE)IT OF TOTAL
)IILLIEQIJIVALU’!S PU LI’TU
A$IO
Figure 4.3. Pip.r diaqrsa of percsntags aillisquivalents of
aajor cations (left triangle), anions (right triangle), and
eoebined ions (diaond). Values are grouped according to
type of sa pls locality: 5)01 GW-ground water in shallow
aquifer at Silver Mountain Mine where I II-, $2, $3, and M4
represent aonitoring wells; $101 S*’onsite surface watsr
where ST is stock pond and SE is seep; and MSC-offsit.
ground water in Horse Springs Coules where Ii and 12 are
irrigation wells and RE is a residential water supply well.
, )
RI cHAPrER 4
PAGE. 24
*—‘ CA CL
-------
RI (AF ER 4
PAGE 25
— I
Figure 4 • 4 • Th distribution of electrical conductivity (EC in
zS), cyanid. and arsenic ( 1 and AS in uqfL), and nitrate
( $03. in s/L) in ground water and surface water. Electrical
conduativity 1 cyanide, and nitrate values indicate the
presenc, of a dilute plus. (shown by interred contours)
utendi fr the leach heap in the downgradiant direction
to the southeast. As discussed in the text, other
paraseters which show a sisilar distribution include sodium
potassius, and fluoride. The distribution of arsenic, on
the OthS handy indicates highest values associated with
sources to the west of the heap including sine drainage, the
sine dusp , or bedrock. As discussed in the text, elvat.d
antinony and several other setals also originat, west of the
heap.
. — I_ r
c ’
IXPLAN*T ON ___
2.
— rrv
• - I
r ri c vr
— 1
\
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RI CHAPTER 4
PAGE 26
4.4 NATURE OF CONTAMINATION
The analytical results of rock, soil, and water samples and
the risk evaluation in Chapters 6 and 7 indicat, that two
potential contaminants of concern, cyanide and arsenic, merit
further discussion, particularly with respect to their amount and
chemical form.
4.4.1 Cyanide
4.4.1.1 Cyanid. in Rock and Soil
me quantity of cyanide in the leach heap may be estimated
by combining measured concentrations with assumptions concerning
th• central part of the heap where samples were not collected.
The distribution of measured concentrations suggests preferential
concentrations of cyanide at the tOe of the heap, where leachate
discharged . into th. pond. Relatively high concentrations would
also be expected next to the liner under the heap materials,
since leaching solutions would hav• flov.d through the heap and
saturated materials on the liner befor, travelling toward the
pond..
Therefore, for th• purpos. of estimating quantities, the
Center was divided into two equal parts. The upper half was
assumed to have conCentrations of cyanid, comparable to that
found in the top samples, whereas th. lower half was assumed to
be comparabi. to the toe samples. These assumptions should be
environmentally conservative, becaus. they probably overestimate
the amount of cyanide in the lower half of the heap’ s center.
Table 4.9 lists the data used to derivs estimated values for the
quantity of contaminants in the heap. The volumes of different
parts of the heap irs taken from Appendix C, arid the
concentrations irs from Table 4 • 1.
The . . data and assumptions yield an average mass of 200 kg
(440 lbs) of cyanide, as C I I, in the heap. About 2000 kg (4400
lb.) of sodins cyanid. (Na ) is believed to hav, been applied to
the heap during leaching operations see Section 1 • 2 • 2). This
amount of Na would correspond to 1060 kg of . Therefore, on
the basis of averaged value., approximately 19% of the cyanide
originally applied to the heap remain, in place. Tbs remainder
of th• cyanide either discharged to the leachat. pond, where it
was removed in metals-laden or. solution or was degraded by
treatment or natural processes, or infiltrated intO the ground
through the liner or through spills.
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RI CHAPTER 4
PAGE 27
Table 4.9. List of cyanid. and arsenic Concentrations and sass
in the heap and pond bottom.
Totol
111 10.
4.75 64 660 300 310 3100 1 0
Moos dstsruboo I roo vslis If d l I f.rsvst psns of hs (A,,..iIla?) .lty .1 93 tbs/ft3.
To. ti Is .si st s In .JIx 7; sI* vs$ with -
oorth t, soot ulepss; tsp vst with tsp I SIf of c.it’ bIoe ;
ooisr I s with ttoo hi lt if cootur bboo •— p.d with 3fssi dssp blot
_ - - —.
MUD
MU Of M W
ft3 10.6 Ihi 10.6 k
Tsp
27720
2.63
1.19
Sids
43413
4.12
1.17
Too
12144
1.13
0.32
C tsr
Z77 2P
2.63
1.19
s,W
6379
0.61
0.27
Totsl
1175??
0 0 1 k.
1MIU
Ikg
AVtlA 5
MU
kg
IMS
OF CONTAMIIAIT
kg
AWSAGI
i
AVERAGE
TDD.L
Cyaaigg
1.7-14
0.2 3.3
26-175
64 -175
5.4-101
5.1
1.4
1%
1%
fl
2.0-17
0.4
45
102-2%
1.3-2?
6.2
-00
6.9
2.6
SS
126
1.9
iS
5.?
121
278
20
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RI CHAPTER 4
PAGE 28
The chemical form of the cyanide may be estimated from data
on total and weak acid dissociabi. cyanide and from correlation
with concentrations of other elements found in the heap. Figure
4.5 shows the relation between total and weak acid dissocjab le
cyanide for data from Table 4.1. A linear regression calculation
illustrated in Figure 4.5 indicates that about 1]. percent of the
cyanide is in weak acid dissociabi. form. As noted in section
4.1.2, some other elements, including sodium, copper, zinc, and
lead, tend to be pr.f.rentially concentrated at the to. of the
heap along with cyanide. Of thea. elements, sodium would be the
most likely to combin. with cyanid, in a weak acid dissocjab le
form.
The less soluble forms that make up the remaining 89% of the
total cyanid. may’ consist of a variety of compounds. The high
iron content of the heap material suggests that iron cyanide
compounds may predominat. in th. poorly soluble fraction.
Preferential concentration of zinc, copper, and lead at ths toe
of the heap suggests these elements may also be incorporated into
iron cyanide compound Chapter 5 discusses contaminant mobility
in relation to the probable forms of cyanide.
4.4.1.2 Cyanide in Water
The rssultt â’t the field and analytical work indicate that a
dilute cyanide- plum. sxtend* from- the hap toward Well 3, 25 feet
south of th. heap in a dovngradient direction. The concentration
of cyani -in ground-water at th. site is about 1,000 to 10,000
times lower than the estimated concentration of the original
leaching solution.. Th. plum. does not extend as far as the
nearest water supply well, located 2 mile. doimgradient in the
Horse Spring. Coule. aquifer.
- Between June and July 1989, cyanid. concentrations increased
by a factor of about 10 in Well 3. The increas, occurred during
a period of decrsssinq water level at Well 3 and rising levels at
the othas wall... The increas, in cyanide was not accompanied by
a corr oudizq increas. of the sam, magnitude in other
constituents. Th, significance of the increas, is not known.
Perhap. cyanide- is held in moderately soluble solid phases in the
aquifer meterial near the heap and is mobilized at low levels
by transient infiltration events. Th• data for weak acid
dissociabi. cyanide indicate that about 10-30 percent of the
aqueous cyanide is in the weak acid dissociabie form.
‘ 1
-------
RI CHAPTER 4
PAGE 29
-J
E
- 10
z
0
-I
0
1•
100
.
TOTAL CN — 11.2618 (wAD CN) — 1.74403
5
I I II liii I I I I I I I IJ
1 10
WAD CN,
mg/L
Figure 4 • S. Graph shoving correlation between total cyanide and
weak-acid dissociable (WAD) cyanide in samples of leach heap
material • A linear regression curve that accounts for 90%
of the residuals is shown as a solid line through the data
points.
U
S •
.
.
S
S
•
S
S
S
S
S
S
-------
RI cHAPTER 4
PAGE 30
The relatively high concentration of cyanide in Soil beneath
the pond liner suggests that at least one likely pathway to
ground water is leakage through or over the liner.
concentrations in the soil under th. pond liner are comparable to
those found at the to. of the heap and probably could only have
resulted from direct contact of the soil with leaching solutions.
Drainage of leaching solution or runoff into th. subsequently
plugged well southeast of the heap was considered as another
possible pathway. However, samples of this well taken in 1981
and 1983 (Table 1.1) showed cyanide below detection limits (0.002
mg/i) and argu. against the well as a contaminant pathway to
ground water.
4.4.2 Arsenic
4.4.2.1 Arsenic in Rock and Soil
The quantity of arsenic in the heap may be estimated in a
manner similar to that for cyanide, using heap dimensions and.
measured concentrations (Table 4 • 9). Unlik. cyanide, the arsenic
was not preferentially concentrated at the to. or in any other
part of the heap. Arsenic quantity can thus be estimated based
on the rang. and average of values for all heap samples. Using
th• data in Table 4.1, a range of 64 to 65G mg/kg for arsenic in
23 samples, or an average of 398 mg/kq. yields a ma ,.. range of
310 to 3100 kg or an average of 1900 kg (4200 ibs) of arsenic in
the heap.
The av.rag. concentration of arsenic in the leach heap
samples was about half of the averag, concentration in the
samplea of unleachsd mine dump material (Figure 4.2). Assuming
that the heap material originally contains a similar amount of
arsenic to that in the mine dump, perhaps as such as half of the
arsenic originally in the heap say hay, been removed by leaching.
ms present capacity of the heap to be a source for arsenic
in ground. water should be similar to that of the abandoned mine.
In 198t arsenic was detected at an elevated level of 110 øg/1 in
the leachate pond. Th.t. concentration indicates some leaching of
arsenic from ths heap at that time. A comparabl. level, up to 9].
j g/l, occurs in mine drainage at present (Figure 4 • 4).
Currently, the mine drainage contain, the highest arsenic values
deteCted in any water at the site.
The mine drainage concentrations and 1984 leachate value may
provide an estimate of the general leaching potential of arsenic
from bdrock and from mined materials. Ths potential fdr arsenic
leaching in the future depends on the fore in which arsenic
a?
-------
RI CHAPTER 4
PAGE 31
exists in th. rock. The form of arsenic was investigated in a
petrographic analysis of heap samples (Appendix D). On the basis
of electron micropreb. results, arsenic probably occurs as sub-
microscopic sulfide minerals, including arsenopyrjte and arsenic-
bearing pyrite. The mobility of arsenic in the sulfide form is
discussed in Chapter 5.
4.4.2.2 Arsenic in Water
Arsenic occurs in ground water at concentrations as high as
15 sg/L. No clear influence of the heap is apparent in the
distribution of the arsenic (Figure 4.4). A comparison of
arsenic values for onsit. wells with thos. of wells of f site
suggests a somewhat higher level of arsenic in ground water at
the sit, than in the main part of the Horse Springs Coulee
aquifer. Arsenic in on-sits ground water samples ranged from 3 • 3
to. 15 øg/I., with an average of 10 Mg/L for 4 samples. Offsite
samples had values of c i and 1.6 Mg/L.
4 • 4 • 3 Sources of Contaminants in Ground Water
The distribution, of cyanide in ground water, relativ. to
flow direction an to the leach heap, clearly shove that the area
of the heap and leachat. pond is the source of thi. contaminant.
As discussed under the extent of contaminants in Section 4 • 3 • 2.2,
several additional parameters, including sodium, potassium,
fluoride, nitrat., and nitrite show the same distribution pattern
as cyanide for Round 3 samples. Th. elevated levels of these
parameters downgradi.nt of the heap can be inferred to originate
from leakage spillage, or overflow of leaching solutions used on
the heap.
As noted above, several additional parameters including
arsenic, anti ny, barium, chromium, copper, lead, iron,
manganese, nickel, silver, and zinc show a divergent distribution
pattern with pr.fersntiafly greater concentration, in Wells 1 or
2. Although present in heap materials, the distribution of these
parameters in ground water clearly indicates an origin other than
the heap. Wells I aM 2 are doimgradient of thre, potential
sources: the sin. d , mine drainage (well 2 only), and bedrock.
The relative influenc. of thes, three potential, sources is
somewhat speculative at present. The proximity of the well
intakes to both bedrock and to the probable infiltration path
through th• sin, dump- (Figure 3. ib), suggests that either or both
could be the primary source for thes, parameters.
Two of the probable bedrock contaminants, arsenic and
antimony, have higher concentrations in well 2 compared to well
-------
RIcH?IPTER 4
PAGE 32
. The elevated levels of arsenic and antimony in well 2 suggest
thatWhatever bedrock or mine dump influence exists for these
contaminants is furthSr enhanced by th. mine drainage. The high
levels of arsenic (ROund 3) and antimony (Round 1) in the stock
tank also suggest that mm. drainage is a potentially major
source of these contaminants to ground water.
4 • 5 SU1O ARY
The nature and extent of contamination at Silver Mountain
Mine has been evaluated by field geologic mapping, hydrogeologic
investigation, incorporating four monitoring wells and three
offsit water supply wells, and analysis of the chemical
composition of 34 samples of leach heap and mine dump material,
20 samples of nearby soils, and three rounds of water samples
from seven wells and two surface water site.. Elevated levels of
contaminants in solid material are largely confined to mined
bed_rock that has been crushed through the process of mining, and
abandoned in piles (mine dump), or that has additionally been
abandoned after leaching with cyanido solutions (leach heap).
contaminants are, considered SW ated in relation to background
soils that sa be influenced by natural erosion of bedrock and
glaciofl zvial deposition, but ar. not influenced by mining
activities. Contaminants that appear to be elevated relative to
background soils consist primarily of arsenic and other metals
and metalloid_a in the sin, dump, and these same constituents plus
cyanide in the leach heap. The same contaminants occur at lower,
but still el.vat.d, concentrations in shallow soils beneath the
heap leach collection pond and in a localized area of shallow
soil within 25 feet adjacent to the heap.
Elevated levels of contaminants also occur in ground water
at the sins sits and in surfacs water in a stock pond fed by mine
drainage. In this respect, elevated aqueous contaminants from
the heap are considered elevated relativ, to concentrations
upgradient of the heap. Elevated contaminants from other
sources, the sin, dump , sine drainage, and bedrock, are
considered elevated when more concentrated than the furthest
dovngr.dient monitoring well at the site, well 3. Elevated
constituents in ground water consist of cyanide and slightly
elevated levels of sodium, potassium, nitrate, nitrite, and
fluoride originating from the leach heap, and arsenic, antimony,
barium, chromium, copper, chloride, iron, lead, manganese,
nickel, silver, and zinc originating either from bedrock or the
mine dump . Additionally elevated arsenic and antimony occur in
sine drainage.
‘I!
-------
RI CHAPTER 4
PAGE 33
Ground water contaminants from the leach heap extend in a
plum. at least as far downgradient as the furthest monitoring
well, well 3, 50 feet southeast of the heap. Ground water
contaminants from either the sin, dump or b.drock ax.
substantially reducsd at well 3, which is 100—200 feet
downgradient of thes. potential sources • No ground water
contaminants influence offsit. water supply wells 2-4 miles
dovngradient to the southeast of the mine sit..
Piper, A.X., 1944, A graphic procedure in the geochemical
interpretation of water analyses: American Gophysical Union
Transactions, v. 25, p. 914—923.
Russ.ll, Robert H., and Eddy, Paul A., 1972, Geohydrologic
evaluation of Aeneas Lake-Morse Springs Coulee, Okanogan
County, Washington: Washington Department of Ecology
Investigations, January 1972, 16 p., 1 app.
-------
RI HAP ER 6
PAGE 12
300 and 350 ug/day respectivelY (USEPA, 1989.; 1989g). Estimated
intake of these compounds from the Silver Mountain Mine site is
low compar.d to the average daily intake from food, which is not
associated with adverse effcts. Thus, the lack of toxicity
information for these elements is expected to have a minor impact
on the findings of the risk assessment.
The second major area of uncertainty is evaluation of risks
from darmal contact. Dermal Rfd’s have not been developed,
therefore oral Rfd’s were uased by converting the orally
administered dose to an ad dose. Sinc, there is little
data in the studies used to develop Rid’s r.garding the amount of
chemical absorbed, it was assumed that only 5% of the orally
administered dose was absorbed in the GI tract. This assumption
is believed to b conservative and could have a significant
impact on the results of the risk assessment.
6 • 3 EXPOSURE ASSESS1 T
6.3.1. Potentially Exposed Population.
Current. The 1987 community relations plan (Woodward-Clyds
Consultants, 1987) and documentation for the NP!. listing of the
site provid, information about the current population and
demography in the sit. vicinity. No significant changes in the
population distribution of the area are believed to have occurred
sinc, ths information was assembled.
Within a three-mile radius of the sit ., fswer than 20 people
ar. served by watar supply veils. The land immediately
surrounding the sit . is ovned by a Loomis resident who uses the
land for cattle grazing. Th. nearest residence is a single
family dwelling on a far. thre. mile, south of the sit.. At this
location a domestic wsll (sampled during the Remedial.
Investigation) serves th residence, and a larger well supplies
water for irrigation. The nearest well, used for cattle watering
and for irrigation, i. approximately two miles from the sit..
The sit. is located midway between Loomis (population 200) and
Tonasket (population 1055). The largest town in Okanogan County
is Omak (population 4,000), 26 miles south of the sit ..
Use of the site by local teenagers has been reported by the
land owner. Early reports indicate that warning signs posted
around the site were removed more than once. Ecology records
also document that after the placement of the pond and heap
cover, much of the rop. used to hold this down was removed.
Based on the above information, only infrequent visitors to the
site ar. thought to be currently exposed.
C’
-------
RI CHAP’rER 6
PAGE 13
Future. It is expected that the site will continue to be
accessible to visitors in the future assuming there is no clean
or remedial action. Others who could be exposed in the future
include workers at the site or residents if people choose to liv
there. If it becomes profitable to continue the original mining
activity, exposure to Workers, ie. miners, would be a distinct
possibility. Workers and residents are expected to spend far
more tim. at the site than infrequent visitors, and as a result
will be at greater risk. Since current exposures are low in
comparison to potential future exposures, only future exposure
scenarios will be quantified in th. risk assessment.
6.3.2 Reasonable Maximum Exposure (RME)
Draft revisions of the preambl. to the National Oil and
Hazardous Substances Pollution Contingency Plan (NC?) (USEPA,
1989L ) indicate that remedial actions at Superfund sites should
be based upon the “reasonable maximum exposure”. This is the
highest exposure reasonably expected to occur at the site, and i
intended to protect currently exposed individuals as well as
those who may be exposed in th. future. The method of
establishing the “reasonable maximum exposure” for Silver
Mountain Mine follows.
Of the current and futur, potentially exposed populations
described in 6.3 • 1, workers or residents exposed in the future
are expected to be at higher risk than those who currently visit
the site only occasionally. Therefore, estimating exposure and
risk based on future exposure scenarios is expected to be
protectiv• of both currently and potentially exposed populations
and will be used to develop the reasonable worst case.
As far as could be determined, the Silver Mountain Mine sit
has not bsen occupied in recent times. At present the nearest
residence is. three miles away, roughly in the center of the Hors
Springs Coule.. The nearest population center, Tonasket, is six
mils distant. Residential growth into the immediate vicinity o
th• Silver Mountain Mine sit., though possible, does not appear
likely’ in the near future. In addition, ground water
availability in the immediate vicinity of the mine is very low i
comparison to the center of the coulee (Chapter 3), making the
sit. less desirable for residential occupation than areas of
greater groundwater availability, assuming groundwater is used a
a drinking water supply.
The site has a history of industrial. use (mining) beginning
in 1902 with the Silver Star Mine, and most recently the cyanide
leach operation in 1981. It is possible that mining activities
could occur again if it became profitable. Given the previous
history of the mine, limited ground water availability, lack of
-------
Silver Mountain Mine Mining Waste NPL Site Summary Report
Reference 2
Letter Concerning Cyanide Contamination
at the Silver Star Mine; From Patrick D. Ewing, Chemist,
Precious Metals Extraction, Ltd., to Dennis Bowhay,
Washington Department of Ecology; August 20, 1982
(t)
-------
PATRIC)( 0. EwI
115
URTo ’ , ‘ASHI GTO
AUGUST 20 ’ 1332
CEPA THE T OF ECOL Gr
36fl wEST lAS GfON E u!
Y4 IW4 , WA5hijI GTO’ 999 3
E: CY- toE CONIA ‘4ATO T T ‘SILVEq STa.
CEA wq. O . ’4v:
TI4IS LETTER IS TO I F w i o u OF CERTAuj FACTS NICH I REG4RCIAIG
S LyEc STAQ INE’ NEAR TO’d4S ET, 4SHINGTON. A5 TO o YOU OURIHG OU WO J.
CONVERSATION OF JIJLr iS. 1932, 1 WOR EO AT TsiS MINE FROM ‘dnvE EQ 1983 r ;
JANUARy 1981. i as E P .oYEo £5 A Ci4EWIST TO HELP OPERATE THIS FACILITY. T_
CO ’PANy WHICH WAS ATTEMPTING TO OPERATE THIS MINE WAS CALLED PRECIOUS ETAt
EXTRACTION, I NC. (ME INC.) • A ASHINGTON CORPORATION. THE PRESIDEPIT OF P :
c. was J. WAYNE TATMAN — T E AN WHO HIRED ME. HIS SILENT PARTNER WAS .
PA1R(C MORRIS. THERE WERE SEVERAL OTH R INVESTORS INVOLVED UHO I KNOW OF.
1 1. 1Ev WERE O(’UGLAS OSTREM. C. JAMES ENGLAND. AND MEL PRUIT. ALL OF THESE
PEOPLE A ! FROM THE SEATTLE AREA.
THIS MINING TECHUIDUE IS CALLED HEAP LEL 4 CYANIDATION £NØ INVOLVES
? OCE5s OF LEACHING METALS FROs ORE USING A CYANIDE SOLUTION. THE CYANIC:
OLUT ION IS PUw?E3 TO THE TO? OF A PILE OF ORE AND ALLO WEO TO LEACH TO T
OTTuM OF THE PILE WHICH IS LINED WITw PLASTIC. THE PLASTIC DRAINS TO A
DITCH ALONGSIDE THE PILE AND THf METALLIC CYANIDE IS RE Ov PROs THE SOLUTION
USING O iE OF A VARIETY OF CHEMICAL METHODS.
MY CONCERN PRESENTLy IS THAT THE CYANIDE HIS NOT qEEN DESTROYED.
IERE L30jjT TWENTY DRUMS OF SODIuw CYANIDE (431 POu os EACe ,) WHICH WERE AOCEC
TO THf PROCESS IN ADDITION To SEVERAL TONS OF CAUSTIC AND LIPE. THE EATER
S PLES WHICH I CHECKED HAD CYANIDE LEVELS GREATER THAN ONE THOUSAND PPw USING.
iRMA STAaO IRD METHOD 4IZ.C. iaee AND I Pw GREATER THAN 11. IN ADDITION TO T .E
FREE CYANIDE, THERE MAY BE SU9STANTIAL AMOUNTS OF HEAVY METAL tYANIDES O
OTHER COMPOUNDS WHICH MIT PRESENT A THR fl TO THE ENVIRONMENT INCLUDING THE
GaO,JNO WATER. THESE CONFOUNDS MAY if FOUND IN 114€ DITCH WATER £NØ SLUDGE S
‘ELL AS THE ORE PILE.
THERE IS A DRAINAGE WELL 9? THE FENCE LINE 130uT THIN?? FEET FROM 1
Polio WHICH WAS PUT THERE TO DRAIN THE ENTIRE LOWER AREA WHICH FL000ED FRO
TIME TO TIME. IF IT HAS NOT ALREADy HAPPENED, TsEqE NaY 9€ a SUBSTANTIAL RAIN
O S’O. FAIL ONTO TIlE PILE. WHICH EXCEEDS THE CAPACITY OF THf DITCH, FLOWS INTO
THIS WELL AND THUS CONTAMINATES Twi GROUND WATER DIRECTLy. THERE IS ALSO SOME
)UEST ION IPI MV MIND ABOuT THE INTEGRITy OF THE LINER iTSELF GIVEN THE EXISTING
CIRCUMSTANCES. IT HAS ALREADY COLLAPSED NEAR THE FRONT EDGE OF THE DITCH A?,O
MAy if PUNCTURED BY FREEZING ICE. Y LARGE ANIMALS WALIIING IN IT. T
VANDALISM, OR BY A COM9IIATIQN OF THESE.
AN ADDITIONAL CONCERN IS THAT THE LEACHATE MIGHT ESCAPE THE PLASTIC LINER
PY TRAVELLING SIDEMAYS diTH 1N THE PILE AND FIND £ PITw OVER THf EDGE OF T’
PLASTIC WHERE THf ORE HAS COLLAPSED. 9 SAd THIS HAPPEN DURING THE TIME I VAS
THERE AND THE CONOITI3p .S WHICH CAUSED THIS TO HAPPEN HAVE NOT BEEN CORRECTED.
-------
THE FOtj..OWING LIST INCLUDES ALL OF THE PEOPLE WHO I 4NOi TO WAVE qEE* OI FCT’y
INVOLVED I’ THE SILVER STAR MINE’
J WAYNf TITMAN
i913 CAMAS COURT S.E.
NTON wASHINGTON 93055 j
PHONE 206—255—0280
PqESIOENT NQ GE’ ERAL MAP4tGER OF PHE INC. ORIGINAL NAGE AT SIIvER ST.R
DOUGLAS OSTREM
14 2 ‘iE 32ND
!ELLE UE’ WASHINGTON
PWOP,E 206—8917879
INVESTOR i i PVE INC. LATER WAS APPOINTED GENERA ,. MANAGER OF •SILVE Sra
OIP4S A SILVER MINE NEAR CONCONULLY’ WASHINGTON
C. JAMES ENGLAND
4444 !ONSY 9RAE DRIVE
ELLEVUE’ WASHINGTON
P OHE 206—154—0999 OR 206 —32S -1i1? OR 206—921—20 1
INvESTOR AND PILOT FOR PVE INC.
SUPPOSEDLY WAS BOUGHT OUT BY PAT wORRIS IN LATE JANUARY 1981
‘EL PRUITT
7 2 WEST CASINO ROAD
APT. V133
EVERETT, WASHINGTON 98224
CC’ STRUCTED PILE OF ORE WITH WAYNE TATNAN • BOUGHT OUT BY TATMAN BEFORE I WA5
MIRED.
G. PATRICK NORRIS
13 J1 9TH Nd
SFATTLE, WASHINGTO’O
P ICNE 236—365—4331 (HONE), 206—363•3613 (WORM)
IPi ESTOR IN P E P lC. BOUGMT OUT JIM ENGLAND
HAS A BUSINESS INTEREST IN MERFYS AND MEENER FOODS • MULTIMILLIONAIRE
OQ. (WILLII ?) GROVES
PsONE 604—084 .9934 (WORK). 4- 41•4383 (HOWE)
WAS A CONSULTANT TO WAYNE TATNAN AND PMf INC.
WESTERN TESTING LAGS
‘du qER 3 — 1386 LINDI WIT
SPARKS. NEVADA 89431
GILL CLEW ASSAYER
PERFOR ’ED TESTING OF CRE FOR P’E INC.
BILL PETERSON
ORIENT’ WASHINGTON
PHONE 509-634.2315
LEASED EOULPVENT TO PME INC.
-
-------
Silver Mountain Mine Mining Waste NPL Site Summary Report
Reference 3
Excerpts From Potential Hazardous Wastes Site:
Preliminary Assessment, Silver Mountain Mine, Washington;
Washington Department of Ecology; Undated
q
-------
S. ,. ‘0
POTENTIAL HAZARDOUS WASTE SITE Ca t, Okanog,
PRELIMINARY ASSESSMENT
MEDL
Summary MeIeora, um ., 85
Name and Lo tion :
Silver Mountain Mine j.
.oosis . VA (509) 223—3175
T38N, R26E, S.c 34 VM S’t ,StJt ( )Actn ,. ( (
‘ Sit e Description ITSD Activities: ______
Sit. is an abandoned silver/gold sin. located in N central W A. In an
effort to extract precious sinerals fros sine tailings a Proce caLj
heap leach cyanidation was aced La which a plastic liner was laid and
the sine tailings piled on top. Apprex. 20 druss of sodium cyanide and
c cv. tons of caustic soda were poured ou & leachate cOllected in basin.
Waste Type$/Q ntjtj.i / Characteristics : —
Tailings pile — Approz. 400 cubic yd of sacerial hay, been contas nac.4
by cyanide. Leachate collection basin — Approx. 30,000 gal of liquj4 in
the coll e tL basin is contaminated by cyanid, and ftuserogs heavy
metals.
Physicai/5 i Environment:
Sit, is in a remote area with th. nearest residence 3 si to the NV. Area
is primarily used Qor cattl, grazing. Sit. is in an arid region with
evapocranspiration equaling rainfall. Nearest surfac, water is an inter-
sittent stream 2300’ to th. east etch a less than 3Z slop, of interven-
ing terrain,
POIIut. t MObIIiZ1J /P*U Iy$jRjSk:
Ther, is an uncappe4 veil. on sits providing direct access to groundwater
at a depth of about 20’. Soil is a highly permeable sandy gravel. Signi-
ficant potential exists for CV conc$einatioa. The only ases of CV within
3 si are irrig., stock vacering and a. single upgradie veil 3 si away
vbich serves 1 family. Littl , potential for surfac, eater contamination.
Priority Aue me t,p ji Reduction Category :
M!DIUw Contaminatie, probably not a threat to off—sit, pop. bat may
represent. a series, health threat to any people, livestock or wildlife
on site. C7$sL4. contamination over 200 tim*s above EPA. limits have been
seasured is collection basin. VDOI has already twice neutralized cyanide
in basin bnt COnCs$t?aejons have always increased again with leaching.
FoIlo p Recommendations :
Site should be immediately fenced and posted, Due to the relatively
ssall quantity of hazardous material and the confined nature of the
waste, remedial action is feasible. The possib i lity of removing the con-
taminated material or continuing neutralization action should be evaL-
uated.
fir,
-------
POTENTIAL HAZARDOUS WASTE SITE IDE :FUCATC
01 5141. 32 S.ti mo,e
PRELIMINARY ASSESSMENT
Part 2 - Waste Information D98 0722739
II . WASTE STATES. QLJANTITIE5. AND CHARACTERISTICS
SI aca’ St .t . .
(crIocS eli IM* .551V1
áiijsts Qtj1t tit at S e .
(m Mt’SI Of i 51• 4* 4ilI,tI
03 0 5 51 5 ChrIclI,IsIica ICN * 511 1 1 10 1 $Ooly
SI
(X A soi . ( )I.
Ni S1 50 dUVSPCSIII
( A. .sc ( )i. Sol ls ( )i iqsiy VO14t II
( )s aowos, Jr,i..( OI i. aw
)c SIwdq . ( )c. c ..
C ) o
Ci 4150
N5 S I Or s:
( )e Corroeav. ( )P l,’V t.sis ( )j.
C )c *so.osCtsvI C )c. PI.ses ( )ii as.tv.
( ) 0 SfIi 51 lt C ) I9 Wt$ 5 ( ) I..
(__) Net 0 00l.c.5u .
III. WASTE TYPE
Cat.qoe,
Swosiag’ice N 01 Cross Aosjrn
Sludge
Oily Waits
Solvents
Pesticides
02 IJnIC or
t SIu’ 5
03 C i.s.uts
SLU
OLW
SOL
PSD
0CC
Other Organic Chemicals
IOC
Inorganic Chemicals
4 150
Cu yd
Sus of solid and Liquid was eg
ACO
• X
Acids
Bases
Unknown
N/A
Caustic soda
ME5
IV. H
Heavy Metals
AZARbOUS SUBSTANCE
Unknown N/A cached fros sins taiiin s.
(see Appendix for most fr.guevitly cited CAS numbers)
03 CAl Nq aSw 45 S1Si$5S100I U..I 5$ C.ic. .,iu .m ti
te t. .!,ef .
143339 20 druss poured on Unknown N/A
Ii Cat.
33 SjISIW e NS
bC
Sodius cyanide
ZOC
Caustic soda
5 50 (VI&QN jNTAL
1310732
TK
tailinç. oil.
Several eons on pile
Unknown
N/A
LOC
Total cyanide
57135
Mine tailings
360—390
ag/kg
LOC
Total cyanids
57135
Groundva;er on •it•
<0.002
sgJJ.
OC
T
F
F
F
F
F
F
Total cyanide
Copp.r cospeundi
Zinc cospounds
4 :: ::: 0:5de___
Lead cospounde
Nickel coapounds
Chro
9!:;:!!
V.FIED5TOCKS
57135 sachet. co]. basin
n macbats eel. basin
a n L.achate co ] . basin
T n Leechate co ] . basin
- isachats eel. basin
unknown t.eachats ee l . basin
Liachats eel. basin
• E n Leachst• co]. basin
• n machats co]. basin
ETn machate eel. basin
0—1100
0.03—100
Q. .42—190
.0ZL.0
ag/i
ag/I.
ag/i
ag/i
9.3340
ag/ I
.16—0.22
.05—3.0
.02-0.17
ag/i
ag/i
ag/i
.L20.91
ag/i
42
ugh
(see A psnd ?F XFnumbers
,— --
- ii r - - .s. S2 M o...T Cst v SI 0S 52 CAS MumDSr
......E.g . ........ ‘ ‘
- --
FOS
IT 2 QL
cots weci EF7 encu. e.g. stat. files, etc.)
VI. SOUl
CES OF INFORMATION
WOO! Files
0
-------
4
POTENTIAL HAZARDOUS WASTE SITE LL. IDENTIFICAT
PRELIMINARY ASSESSMENT °‘ Si. ,. • •
Part 3 - Description of Hazardous CondIt,o g D98o7z27s
II. HAZARDOUS CONDITIONS AND I
NCIDENTS
0l ( ) _‘-•, 32 (
(C0ntinu. )
) Obs vuo (Oil.
OS N.,., ,.,.
J
(
) etiøi .i ( ) A
O.ic,i,im
No 1 observ.d.
ot ( X ) * 03 (
) Obiir ,. (Oit .
0 5 N1. ’et ,v.
(
) ( vJ .
( ,iqc* .li “i..f Si If lilciss)
The owner reported a dead
cause/effect relationship has
and dead birds on site
r o been established.
but
a detinite
0 ( ) L. CM,I.U .,, sq Chs..i so (
) Obs..-,.S
0 5 NiPPSi (v• D.SC,.aU...
(Dii.
(
) C )
Non. observed.
-
(
)p,,,,,, ( j ui
ii ( X ) UAsi s Cøtaii. s 02 ( Xi ObWv ii (O.s. 08/1 3/82
($S I 5lpsfl/ st$j
03 utis,.. lSlllSlly MfM?.I.
Vast.. i a uncov , plastic lined collection basin. The 0kanag
Co. Eealth Dept. is concerned that the plastic liner may soon decerior.
—• . t!i. P l1 • i ft , w$i 111 4 ttp4 a haive
it ( ) . p ii o,,su . P I N _ n y 02 ( ) ON...rv.l (Dii .:
51 N .FuMO.
None observed.
j
(
)
(
) A,
•
ii ( ) o. C. ta.u.uiit , 1 SIwi SO( ) Ob v (D i i i:
Suii DriM1.
(
I
WW?Ps
OS Nii jy D u...
No severs score drains, WVTPs in the area.
(
)
ot ( ). o,ii 03 ( ) onw ii
iS M1 , 5II,s Diisrisi,
(
I
(
) AUsg
No * reported.
IS Ouwsjs Offis.
N s. klIs, NSas
No ne.
III. TOTAL POPULATION
POTENTIALLY AFFECTED: (10
IV. COMMENTS
WOO! has made 2 attempts to neutraliz, the cyanide with ETH with he 1st
attempt in the winter of 81/82 and the 2nd in the winter of 82/83. The
cyanide in the collection basin has been neutralized after each ac:empt
but concentrations have increased again with continued leaching from the
nine tailjn s.
V. SOURCES OF INFORMATION (cite specific references: stats files, reports, etc.)
WOO! Files; EPA Files; USGS Topo maps (Aeneas Lake and Enterprise,
7 L/2); WOOS report, 1972, Geohydrojogic Evil, of Asnsas Lake — i orse
Springs Coul.., Okan. Co., WA; 3. Nelson, Okanogan Co. ealth Dept.
-------
Silver Mountain Mine Mining Waste NPL Site Summary Report
Reference 4
Excerpts From Record of Decision for the
Silver Mountain Mine Superfund Site;
Thomas P. Dunne, Acting Regional Administrator, EPA Region X;
March 27, 1990
-------
DECLA SA?Io$
for the Silver Mountain Mine
Superfund Site
RECORD OP DECISION
SITE MANE Mm LOCATION
Silver Mountain Nine
Okanogan County, Washington
STAT (ENT OP RASIS MID PVRPOSE
This decisian doct snt presents the selected rnsdjal action
for th. Silver Mountain line sit., developed in accordanc, with
the CoWr. .jvs iviror t j R 5* O ., and
Liability Act of 19*0, as aa.nded by the Superfur4 Anendoent., and
Reauthorization Act of 19*6, and, to the extent Practicable, the
National Contingency Plan. This decision is based an the
Adpinistrstjv. Rcord for this sit.. The attached index
identifies the itw that cospris. the ? 4 i iseraeiv. Record upon
which the selection of r a.dial action is based.
The Stat of Washington h s verbally concurred on the selected
r.a.dy.
ASSESSM 4? OP
Actual or- threatened releases of hazardous substances fros
this sits, if not addressed by ispleasnting the response action
selected in this noa, sey present an 4 ir ent and substantial
endangsr ese to public health, welfare, or the environment.
4. ..
This is tb first and final Record of Decision, because the
entir. site in being handled as a single operabl. unit. The
Silver Mountain sits is an abandoned sins dt where a heap
leachiaq operation left cyanide and arsenic contaa.tnation. The
Washington Depar .z of Ecology stabilized the sit . in 1985,
treating the imeedjat. threat of cyanide in the leach heap. The
selected remedy will provide longtsrm environmental protection
by:
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3
Because this remedy will result in hazardous substances
remaining onsite above health-based levels, a review will be
conducted within five years after commencement of remedial action
to ensure that the rs edy continues to provide adequat. protection
of human health and the environment.
3/ 7)
Date ThO aI P. Dunne
Actinq Rqional Ad iTIistrator
U.S. Environental Protection Agency
Region 10
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A 1
9
Mio’ration Pathways
contamination is believed to originate from four maj.n
sources: the leach heap, mine dump, mine drainage, and
bedrock. Leaching, weathering, erosion, infiltration and
other processes and mechanisms have intermixed contamination
from man—made and natural sources, and transported it to other
media. The potential exposure pathways are through
groundwater, air, surfac. water and soil, contact.
The potential for airborne migration of arsenic or cyanide
is minimal.. The heap is presently covered with a 33 -mu
hypalon ]jn. . Should the liner fail, the top layer of the
heap is so cours. that very littl• contaminated soil would
blow from the heap, as estimated by worst cas. modelling.
Likewise, the potential for transport of contaminants from
the site via surface water is pinimat. Th topography at the
site is relatively flat arid there is n connection with
surface water bodies in th are.. The closest surface water
is approximately two mile. from the sit..
The main potential pathway of off-sit. contaminant
migratioir identified for this sit, is the regional groundwater
system (the Horse Springs Coizlss aquifer) As. stated above,
cyanidé and arsenic were detected in the shallow aquifer under
the site during the remedial investigation. Th• quantity of
water flowing througb the shallow aquifer is very low (with an
estimated specific discharge of 0.1 ft/yr), and it currently
is not us.d as a sourc. of drinking water, rather it connects
with the regional aquifer downgradient of the site.
Groundwater sampling will continue to confirm whether elevated
conc.ntrstious of contaminant. from ths site are affecting the
Hors. Springs l.. aquifer.
Potential pathways for contaminants in soil
include inaJ ztant ingestion (s.q. • while eating or smoking),
direct d.zmel contact, and irk*1 ation of suspsnd.4
particalatse. The last of these is not considered
significant, uric. it is unlikely that contaminated soil
particles will be irih*1.d unless the beep is disturbed.
V I • SU1O AT 07 SITI RZ
Introduction
A basal in. risk assessment was conducted as- part of the
Remedial Investigation to estimate the risks to hia n health
and the envirozasnt that ar. posed by the existing conditions
at the Silver Mountain Mine sits. The basslin. risk
assessment estimated that there are unacceptabl. potential
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25
The treatment alternative reql.iires about a year’s work.
Safety clothing and equipment are required to assure worker
safety, and precautions are taken when materials are hauled
offsjte, as in the above alternative. This alternative has
the lowest short—term effectiveness becaus, the likelihood of
contaminated materials becoming airborne durutg sizing
operations is very high.
Imolementability
Offsits landfilling is easy to implement. Loading,
hauling, and long—term disposal services ar. readily
available, and landfill capacity dos not pose a problem.
future site remediation or monitoring is required. Some
potential for groundwater conta ii ation remains at the site
due to naturally occurring arsenic in the bedrock.
Capping is also easily implemented. The technology to
construct the alternative i. well developed and th. means to
perform maintsnance functions on the cap and monitor the
effectiveness of the remedial action are available.
Treatment is less implementable. ThS technologies to wash
and sirs the contaminated materials and to treat the rinsate
are generally proven, and the availability of equipment and
technical, personnel should b good. Mowever, treatability
tests are r.quirsd to determine how effective this alternative
will b in reducing arsenic concentrations. It is doubtful
that treatment/removal of fines could reduce the arsenic
present in the sulfide mineral form to the cleanup standard of
200 mg/kg (see Table 6 below). In addition, the ARARs for
this alternative might necessitate disposal of wastevater of f-
sit., making implementation more difficult than orginally
planned. Under this alternative, the site requires no future
monitoring, but if treatability studiss indicat.d the need,
capping and groundwater monitoring will be added to this
alternative.
The capping alternative has an estimated capital cost of
$370,360 and annual O&M costs of $39,650. The present value,
based on a 30-year period for sits activities, is $635,600.
Capital costs for th. treatment alternative ar. estimated
at $855,290, and present worth at $1.2 million. No moni.toring
or maintenance costs are included.
Offsite disposal, would cost an estimated $1.4 million.
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13
Toxicity Assessment
Cancer potency factors (CPFs) have been developed by EPA’s
Carcinogenic Assessment Group for estimating excess lifetime
cancer risks associated with exposure to potentially
carcinogenic chemicals. CPFs, which are expressed in units of
(mg/kg/day) , are multiplied by the estimated intake of a
potential carcinogen, in mg/kg/day, to provide an upper-bound
estimate of the excess lifetime cancer risk associated with
exposure at that intake level. The term “upper bound”
reflects a conservative estimate of the risks Calculated from
the CPF. Use of this approach makes underestimation of the
actual cancer risk highly unlikely. Cancer potency factors
are derived from the results of human epidemiological studies
or chronic animal bioassays to which animal-to-human
extrapolation and mathematical extrapolation models have been
applied.
Reference doses (RfDs) have been developed by EPA for
evaluating the potential for adverse noncarcinogenic health
effects resulting from chemical exposure. RfDs, which are
expressed in units of mg/kg/day, are estimates of daily
exposure levels for humans, including sensitive individuals,
below which noncarcinogenjc effects are not expected to occur.
Estimated intakes of chemicals from environmental media (e.g.,
the amount of a chemical ingested from contaminated drinking
water) can be compared to the RZD. RfDs are derived from
human epidemiological studies or animal studies to which
uncertainty and modifying factors have been applied (e.g., to
account for the use of animal data to predict effects on
humans). These uncertainty factors help ensure that the RfD
will not underestimate the potential for adverse
noncarcinogenic effects to occur.
Table 2 lists cancer potency factors and reference doses
for contamjnanr of concern identified in the baseline risk
assessment.
Table 2. Cancer Potency Factors & Reference Doses
Contaminant
CPF
(mg/kg/day)
Reference Dose
(mg/kg/day)
Level of Confidence
Arsenic
50
2. E—03*
Cyanide
none
2 E-02
not established
medium
Antimony
none
4 E-04
low
Lead
none
none deve]’d
Nitrate
none
2. E+OO
not applicable
Nitrite
high
* 1 E—03 = 2. x
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14
Risk Characterization
Excess lifetime cancer risks are determined by multiplying
the average daily dose with the cancer potency factor. These
risks are probabilities that are generally expressed in
scientific notation (e.g., lxlo’ or 1 E—06). An excess
lifetime cancer risk of 1 E—06 indicates that, as an upper
bound, an individual has a one in one million chance of
developing cancer as a result of site-related exposure to a
carcinogen over a lifetime under the specific exposure
conditions at the site. Because these are upper bound
estimates, it is likely that the actual risk is less than the
estimated excess cancer risk.
Potential concern for noncarcinogenic effects of a single
contaminant in a single medium is expressed as the hazard
quotient (HQ) (or the ratio of the estimated intake derived
from the contaminant concentration in a given medium to the
contaminant’s reference dose). By adding the HQs for all
contaminants within a medium or across all media to which a
given population may reasonably be exposed, the Hazard Index
(HI) can be generated. The HI provides a useful reference
point for gauging the potential significance of multiple
contaminant exposures within a single medium or across media.
a. Excess Lifetime Cancer Risks
Future lifetime cancer estimates are based entirely on
exposure to arsenic assuming industrial site usage and
reasonable maximum exposure arsenic concentrations. In
addition to arsenic, other contaminants at the Silver Mountain
Mine site that are known or probable human carcinogens are
beryllium, cadmium, chromium, nickel, and lead. However,
beryllium, cadmium, chromium, and nickel have only been found
to be carcinogenic via inhalation. As stated above,
inhalation of particulates and volatiles is not a significant
pathway for this site. The carcinogenicity of lead could not
be evaluated because a cancer potency factor has not been
established at this time. The carcinogenic risk from exposure
to arsenic is shown in Table 3 for each exposure pathway.
b. Noncarcinogenic Effects
Risks of developing noncarcinogenic effects are presented
in terms of a hazard quotient and hazard index. If the
exposure is equal to or less than the RZD——a hazard quotient
of 1.0 or less-—then adverse effects are not expected. If the
hazard quotient is greater than 1.0, there is an increasing
chance that adverse effects will occur. The hazard indices,
summed across each exposure pathway, are shown in Table 3.
Table 4 shows the noncarcinogenic and carcinogenic risks
broken down by contaminant and medium.
4 ,
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15
Table 3. Carcinogenic & Noncarcinogenic Risks
Pathway/Medium
Soil ingestion
Water ingestion
Dermal contact
Particulate inhalation
Vapor inhalation
Total Risk
2.3 E—04
2.4 E—04
1.9 E—03
0.0 E+00
0.0 E+00
2.3 E—03
Hazard Ouotient
2.7 E—01
3.1 E+00
2.2 E+O0
0.0 E+00
0.0 E+00
5.5
Table 4.
Reasonable Maximum Exposure Risks by Medium
A. NONCARCtNOG NtC
Rfd
Ant 1 ny
Arsenic
ri tr
Bery1ht
Ca niae
Chr n i
Co er
Cyanide
F i isor ds
Manganese
Mercury
Nickel
Nitrate
Nitrite
Selenft.
Si lvr
Thai lii
Tin
21 no
Hazard md ix:
Water
I 7(.OO
2.5E-O1
4 7E-02
5. IE—03
9.8E-02
1.1 .oI
Z.6E-02
4 .2E-O1
2.OE—O1
3 .6E—02
5.7E-03
3 .3E-02
O.OE—OO
O.OE.OO
2. ZE—02
14E—O2
LiE — a z
9.Ot-04
7. 8E-02
1. 1E—O2
3.1
Soil
5.3E-OZ
2. 2E’OO
6. 3E-03
4.ZE—04
2.5€ - az
1.2E-O2
1. 1E—04
3.7€—az
0. 0E.OO
1.6E-02
5.OE—03
8.7E-03
O.0E.O0
0.OE .O0
17E—03
2. 1E—02
L7E—02
0.0E.O0
1.3€—a z
7. 1E-03
2.4
C tn.d Hazard Index:
8. CARCINOGENIC (Arsenic only)
Water
2.4(-04
5.5
Soil
2.1E—03
Tot 1 risk: 2.3E03
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16
Table 5. Stock Tank Drinking Water Risks
Noncarcinogenic R,sk Carcinogenic Risk
CQnOound Mazar quotient C iiOound Risk
Ant tn ny 0 OE.OO
Arsenic 1 6E.OO Arsenic 1 5E-03
Bari i. e 3 4E-03
Beryl li i.e i I 7E O3
Ca n ita 1.7E-02
Chr eiw 3 4f-Q3
CyaniCe 4 1E-03
Fluorice 7 1E-05
Manganese 2.OE-04
Mercury S ?E—03
Nickel I 1E02
Selennaii 0 0E O0
Silver 1 4E—02
Thalliu. s I. IE-0Z
Tin 2.9E-04
Z.4E-03
Zinc SLE-04
Hazard index • 1.7E.OO
The total rioncarcinogenic hazard quotient for the water in
the stock tank is 1.7. Arsenic, with a hazard quotient of
1.6, accounts for nearly all of this risk. The risks
presented by the stock tank are shown in Table 5 above.
Conclusjo s - Human Health Risks
-At the Silver Mountain Mine site, the most important
exposures routes are ingestion of and dermal contact with
soil, and ingestion of groundwater or surface water.
Using reasonable maximum exposure assumptions, arsenic,
antimony, and cyanide are the most important contaminants in
water. Nitrate/nitrite and lead were each present in a single
groundwater sample at concentrations above extablished
criteria, though these samples may not be representative of
overall site conditions. Exposure to arsenic in water could
result in an increased cancer risk of 2 in ten thousand.
There is also a risk of noncarcinogenic effects, mainly
neurologic, liver, and skin related, from arsenic, cyanide and
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/
17
other chemicals. The hazard quotient for these effects is
2.5.
The most important contaminant in soil is arsenic.
Exposure to soil could result in an increased cancer risk of
two in one thousand. The hazard index of 2.4 indicates that
soil exposure could also result in a risk of noncarcinogenic
effects, principally skin and neurologic disorders.
Uncertainty is inherent in all risk assessments. The
major sources of uncertainty in the Silver Mountain Mine risk
assessment are toxicity reference values, assumed future land
use, the actual toxicity/risk of the dermal pathway, and the
water data (as mentioned above). Due to the uncertainty in
these and other areas, conservative assumptions were made in
order to be protective of human health.
Actual or threatened releases of hazardous substances from
this site, if not addressed by implementing the response
action selected in this Record of Decision, may present an
imminent and substantial, endangerment to public health,
welfare, or the environment.
Environmental Risks
The greatest risk to wildlife and plants appears to be
from the arsenic concentrations in the soils surrounding the
leach heap. These soils are contaminated with levels of
arsenic toxic to vegetation and ruminants, and are likely to
be utilized by sagebrush biota, although the area involved is
small. In the future, once the heap cover deteriorates, there
may be some acute toxicity at times from temporary pondirig of
leachate. Soils from the heap and dump may exert their
potential toxicity if they erode, spread out, leach, etc.
There is no current risk to wildlife or plants from
groundwater, and no future risk is anticipated. Surface
- waters, however, attract wildlife, enhancing exposure to toxic
levels of pollutants within those waters. The mine drainage
to the trough will probably continue to be a source of
elevated arsenic concentrations. To a lesser extent, the seep
area may continue to be a source of elevated aluminum, copper,
and lead.
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18
VII. DESCRIPTION OF ALTERNATIVES
The Feasibility Study developed eight alternatives, utilizing
a variety of treatment, containment, and disposal options, to
reduce the risks remaining at the site after early initial
treatment actions. The three alternatives which best met the
evaluation criteria (protectiveness, cost effectiveness,
compliance with regulations were selected for detailed analysis
and are described below, along with the no action alternative,
which must be considered to comply with the NC?. As discussed
further in Section X of this document, the primary applicable or
relevant and appropriate regulations are action—specific. There
are no location—specific ARARs for this site, and the Safe
Drinking Water Act standards are the only potentially applicable
chemical-specific APAR. The alternatives are referred to by the
numbers assigned in the Feasibility Study and Proposed Plan.
Alternative 1: No Action
This alternative leaves the site as-is, with no treatment
or containment of contaminated materials and no restrictions
on site access. The leach heap is subjected to all normal
weathering forces and seasonal water runoff. No ARARs are
invoked, and thus none are violated.
Alternative 2: Gradin . ClavJSoil Cap. Institutional Controls.
and Groundwater Monitoring
This alternative consists of a series of actions leading
to capping the leach heap. First, all contaminated materials
on site are consolidated onto the leach heap, with sampling
conducted to verify that contaminated materials are adequately
consolidated. These contaminated materials consist of surface
soils surrounding the heap that contain cyanide and elevated
arsenic concentrations and approximately 1600 yd 3 of
mineralized mine dump. The leach heap is then graded and
contoured to a shape that will minimize water erosion of the
surface layer and seasonal runoff contact with the reshaped
heap. A soil/clay mixture is placed and compacted over the
graded heap to reduce infiltration of both air and water into
the contaminated materials.
Because the wastes at Silver Mountain Mine are
specifically exempt from the Resource Conservation & Recovery
Act, the remedy does not involve the disposal of RCRA-
regulated waste, and RCRA land disposal restrictions and
Subtitle C closure standards are not applicable. The
Washington State Dangerous Waste Act does regulate certain
wastes containing concentrations of arsenic greater than 100
mg/kg if the waste was generated after 1981. Because the
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19
waste at the site was generated prior to th.i.s date, the State
Dangerous Waste rules are not applicable; however, they have
been determined to be relevant and appropriate to the type of
waste being managed.
The cap will be designed and constructed to promote
drainage, minimize erosion of the cover, and provide long-
term minimization of migration of liquids through the
underlying contaminated materials. Because mean annual
precipitation is only 11.4 inches per year, the cap is
expected to readily meet or exceed these performance criteria.
Long—term operation and maintenance will be conducted to
monitor the groundwater around the site and to ensure the
integrity of the cap.
Groundwater sampling is conducted for five years or more
to verify whether contaminants are migrating. As an added
precaution, a restriction or notice not to disturb the cap
shall be placed on the deed for the site, and a fence with
appropriate warning signs is constructed around the site to
limit access. The community will be provided notice of
groundwater sampling activities, sampling results, and the
potential for contamination of the low-yield aquifer under the
site.
This alternative does not completely eliminate the problem
of the remaining cyanide and toxic metals migrating from the
leach heap, but it does minimize these problems by shielding
the contaminated materials from the conditions that promote
migration of arsenic and cyanide. The cap significantly
reduces natural oxidation of the metal sulf ides and the
remaining cyanide compounds and eliminates casual contact with
the contaminated materials by humans and animals. Future
disturbance of the cap is minimized by the fencing and deed
restrictions placed on the site.
ARABs for this alternative include Occupational Health and
Safety Administration (OSHA) regulations on worker safety,
Clean Air Act (CAA) emission standards during implementation,
- Washington State Dangerous Waste regulations on capping,
Maxim Contaminant Levels (MCLs) for groundwater protection,
and the state’s Minimum Standards for Construction and
Maintenance of Wells.
Construction of the cap should take 2—3 months. Operation
and maintenance (O&M) requirements include semi-annual
groundwater sampling and yearly inspections of the site to
monitor the condition of the cap. The present value cost,
including construction and O&M, is estimated at $635,600.
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20
Alternative 6: Removal and Continuous Rinse to Treat for Cyanide.
Fine Solids to Resource Conservation and Recovery Act (RCPA)
Disposal to Remove Arsenic
The major feature of this alternative is the additional
treatment of approximately 5740 yd 3 of heap, mine dump, and
soil to destroy the remaining cyanide arid remove the more
mobile arsenic. The material is moved to a trommel where it
is rinsed with water (to remove the cyanide and water-soluble
metals) and sized to remove the finer solids. Oversized
solids are allowed to drain and then are left on the site if
they meet treatment standards of 200 mg/kg arsenic and 95
mg/kg cyanide (see Table 6 below). The fine solids are
further dewatered and then transported to a landfill that
meets RCRA requirements.
Treatability tests are needed to determine the proper
operating conditions for meeting the arsenic and cyanide
treatment standards. It is doubtful that this alternative can
meet the arsenic standard of 200 mg/kg, because it will not
remove the arsenic that is present in the tightly bound
sulfide mineral form. The arsenic in this form is not mobile
now, but it will slowly oxidize and become available to the
environment over time.
The rinsate is processed to destroy the cyanide and remove
the soluble metal contaminants by precipitation. Treated
rinsate would be released to the ground if it meets State land
application discharge limits. The discharge of treated
rinsate is regulated under the State Water Pollution Control
Act (RCW 90—48), although no discharge limits specific to this
project have been set by the State. The volume of rinse water
generated is estimated to be 400 gal/hr. The metal-containing
sludge generated by the rinsate treatment is disposed of at a
hazardous waste facility, in accordance with Resource
Conservation and Recovery Act (RCRA) regulations.
ARARs include the OSHA and CAA requirements as under
Alternative 2, and several State of Washington water quality
regulations, including the State Water Pollution Control Act
and the State Waste Discharge Permit Program (although no
permits are required for on—site activities).
No groundwater monitoring or institutional controls are
included in this alternative. The estimated time required for
implementation is one year. Neither 0&M nor monitoring is
anticipated in the cost calculation. However, both
groundwater monitoring and capping may be needed if
treatability study results show that health-based-risk levels
cannot be met through treatment. Estimated present worth
costs are $1.2 million.
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A 0
21
Alternative 7: Offsite RCRA Disposal
The major features of this alternative are the excavation,
transport, and disposal of approximately 5740 yd 3 of
contaminated materials (leach heap, mineralized mine dump, and
surrounding soil). The contaminated materials are hauled in
appropriately controlled trucks to an existing RCRA landfill.
After disposal, the site no longer has any Contaminated
materials stored on it, and there is no need to restrict site
entry and future use. Because the low—yield aquifer is
affected by naturally occurring arsenic in the bedrock, the
community will be provided notice of the possibility of
groundwater contamination.
ARARs include the State Dangerous Waste Regulations for
transportation and disposal of hazardous wastes; the CAA and
OSHA regulations again apply during implementation.
Implementation time for this alternative is 2-3 months. No
O&N, monitoring, or institutional controls are required.
Disposal costs are estimated at $1.4 million.
VIII. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
Each of the four alternatives described in the preceding
section was evaluated according to the following nine criteria:
Threshold Criteria
1. Overall protection of human health and the environment :
whether or not the remedy provides adequate protection or
describes the mechanisms for controlling risk for the
different exposure pathways.
2. Compliance with ARARs : whether or not the remedy ensures
compliance with Applicable or Relevant and Appropriate
Requirements of other federal and state environmental
standards or statutes.
Primary Balancing Criteria
3. Long—term effectiveness and permanence : the ability of
the remedy to provide protection and reduce risks to
health and the environment after cleanup goals have been
met.
4. Reduction of toxicity,. mobility, or volume throuah
treatment : the anticipated effectiveness of treatment
technologies used.
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22
5. Short-term effectiveness : the speed with which the remedy
achieves protection, as well as any adverse effects which
it may create during construction and implementation.
6. Implementability : the technical and administrative
feasibility of the remedy.
7. Cost : includes capital and O&M costs.
Modifying Criteria
8. State acceptance : whether the state concurs with or
opposes the remedy.
9. Community acceptance : whether or not the remedy is
acceptable to the community, and how it addresses their
continuing concerns about the site.
The following section describes how each alternative meets the
various criteria.
Overall Protection of Human Health and the Environment
The offsite disposalS option affords the strongest measure
of protection at the site , in that the contaminated materials
are completely removed from the site. Once the materials are
removed, there will be no restrictions on activities at the
site. However, disposal at another facility merely moves the
risk from one site to another. Some potential for groundwater
contamination remains at the site due to naturally occurring
arsenic in the bedrock.
The capping alternative prevents direct contact with the
contaminated materials, by means of both the cap itself and
the fence erected around the heap. There still remains a
small potential for arsenic and the remaining cyanide to
mobilize and enter the ground under the capped heap; however,
the cap should minimize that potential by minimizing contact
of a ir and water with the contaminated materials. Groundwater
monitoring and contingent groundwater treatment included in
this alternative will assure that it remains protective.
The treatment alternative provides a good measure of
protection, because all of the contaminated material will be
washed and the more mobile arsenic in the fine materials will
be removed and disposed offsite. However, the washed coarse
material, which will remain onsite, will, still contain
arsenic-bearing sulfide minerals. The arsenic in this form
has a low mobility, but over time the sulfide minerals will
oxidize and the arsenic will become available to the
environment. Depending on treatment results (whether health-
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23
based levels can be achieved), capping and groundwater
monitoring may have to be added to this alternative.
The no action alternative does not protect human health or
the environment. Humans and animals can come in contact with
the contaminated materials, and potentially harmful leachate
could accumulate in the catchmerit pond downslope from the
leach heap during wet periods of the year, as the existing
cover deteriorates from natural weathering.
Since the no action alternative fails to meet this
threshold criterion, it will not be considered further in this
analysis.
Compliance with ARARs
The capping and offsjte disposal alternatives meet all
ARARs. The treatment alternative can be designed to meet
ARARs, but some difficulty may arise due to Washington State
regulations governing wastewater. If rinsate treatment
operations cannot be designed to meet State standards, the
wastewater might have to be transported a minimum of 30 miles
to a POTW for treatment.
Long-Term Effectiveness and Permanence
Offsite disposal of the Contaminated materials eliminates
the long-term risks associated with the site. No
institutional barriers or restrictions are placed on the site
and there is no need for any inspection, repair, or
maintenance activities. Some potential for groundwater
contamination remains at the site due to naturally occurring
arsenic in the bedrock.
The capping alternative is highly reliable and effective.
Due to the dry climate in the area, the need for major repairs
of the cap during its 30—year design life is considered very
low. A notice or restriction in the deed to the property
should restrict future owners from disturbing the cap.
The treatment alternative has, in theory, a high level of
long-term effectiveness. The washed materials left onsite are
free from cyanide and soluble—metal contaminants. While this
technology is not new, its effectiveness in meeting the
arsenic treatment standard is not known. The arsenic
remaining in the cleaned materials is in the form of low
mobility sulfide minerals that undergo slow oxidation. Over
time the arsenic would become more mobile due to natural
weathering conditions. No institutional controls or barriers
are included, but if treatability studies indicated the need,
.- .
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24
capping and groundwater monitoring will be added t tnis
alternative.
Reduction of Contaminant Mobility. Toxicity. or Volume
Early treatment actions significantly reduced the
concentration of cyanide in the leach heap. Further treatment
of the leach heap would reduce the toxicity and somewhat
reduce the volume of the washed materials to be left onsite.
Cyanide and soluble—metal contaminants are washed from the
contaminated material, and the rinsate is subsequently treated
to destroy and precipitate the contaminants. The principal
threat, arsenic, is partially removed (rather than treated)
through sizing operations that separate out the fine
materials. Precipitated sludge and fine solids are disposed
at a hazardous waste site. Arsenic in the form of sulfide
minerals remains in the washed materials, but it has very low
mobility.
Capping the heap greatly reduces the potential for the
contaminants to move into the environment, because it
eliminates wind and water erosion. Capping minimizes water
and air infiltration into the heap, thus limiting the natural
oxidation rate of the metal suif ides and the cyanide and metal
complexes; this in turn significantly reduces the potential
for contaminant mobility. Capping slows the natural
degradation of cyanide. This alternative does not reduce the
volume of contaminated materials.
Disposal of the materials at a hazardous waste landfill
does not reduce either the toxicity or the volume of the
contaminants. Placement of the contaminated materials in a
properly constructed RCRA landfill should reduce the mobility
of the contaminants into the environment.
Short-Term Effectiveness
The capping alternative has the highest short-term
effectiveness, as it takes only 2—3 months to implement and
involves the least movement of contaminated materials. Worker
safety is assured through wetting the contaminated materials
to control blowing dust, and taking other routine safety
measures to prevent exposure to contaminated material.
Offsite disposal also takes 2—3 months and requires safety
precautions during the removal of the leach heap materials.
Materials are hauled to the landfill in appropriately sealed
and .labeled trucks to minimize the risk of human contact with
the contaminants.
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25
The treatment alternative requires about a year’s work.
Safety clothing arid equipment are required to assure worker
safety, and precautions are taken when materials are hauled
offsite, as in the above alternative. This alternative has
the lowest short-term effectiveness because the likelihood of
contaminated materials becoming airborne during sizing
operations is very high.
Implementabj ljty
Offsite landfilling is easy to implement. Loading,
hauling, and long—term disposal services are readily
available, and landfill capacity does not pose a problem. No
future site remediation or monitoring is required. Some
potential for groundwater contamination remains at the site
due to naturally occurring arsenic in the bedrock.
Capping is also easily implemented. The technology to
construct the alternative is well developed and the means to
perform maintenance functions on the cap and monitor the
effectiveness of the remedial action are available.
Treatment is less implementable. The technologies to wash
and size the contaminated materials and to treat the rinsate
are generally proven, and the availability of equipment and
technical personnel should be good. However, treatability
tests are required to determine how effective this alternative
will be in reducing arsenic concentrations. It is doubtful
that treatment/removal of fines could reduce the arsenic
present in the sulfide mineral form to the cleanup standard of
200 mg/kg (see Table 6 below). In addition, the ARARs for
this alternative might necessitate disposal of wastewater of f-
site, making implementation more difficult than orginally
planned. Under this alternative, the site requires no future
monitoring, but if treatability studies indicated the need,
capping and groundwater monitoring will be added to this
alternative.
Cost
The capping alternative has an estimated capital cost of
$370,360 and annual O&M costs of $39,650. The present value,
based on a 30—year period for site activities, is $635,600.
Capital costs for the treatment alternative are estimated
at $855,290, and present worth at $1.2 million. No monitoring
or maintenance costs are included. -
Offsite disposal would cost an estimated $1.4 million.
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26
State Acceptance
The Washington State Department of Ecology has given
verbal approval of Alternate 2, capping.
Community Acceptance
Two cominentors suggested using an alternative other than
the selected capping alternative. Community interest in the
site is generally low. A total of three private citizens and
one local official commented on the proposed plan: two
favored a capping option, the official favored taking no
action, and the other citizen gave no opinion. All public
comments are shown in Section XI of this document, the
“Responsiveness Summary.”
IX. THE SELECTED REMEDY
The selected remedy is Alternative 2 (grading and capping the
leach heap; institutional controls; and groundwater monitoring).
EPA and the state of Washington agree that this alternative best
meets the selection criteria. A more detailed description of the
•components of the remedy follows.
Consolidation and Gradina
All contaminated soils and mine dump material will be
consolidated with the leach heap, graded, and contoured to a
shape that will minimize water infiltration. Locations which
might include such materials include the mine dump areas and
surface soils around the leach heap. This work will be
accomplished using conventional earth—moving equipment.
Samples will be collected after contaminated materials have
been consolidated to verify that all material contaminated
with concentrations of arsenic greater than 200 mg/kg or
cyanide greater than 95 mg/kg is made part of the heap. The
rationale for these cleanup standards are shown in Table 6
below.
Table 6. Cleanui Standards for Leach Hear. Mine Dump, and Soil
Concentration
at
Constituent
Standard
Rationale
arsenic
274
mg/kg
max
200
mg/kg
Hazard
Cancer
Index
Risk
=
=
1.0
10’
cyanide
101
mg/kg
max
95
mg/kg
Hazard
Index
0.1
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13
27
Capping
Capping is the most important component of this remedy in
terms of preventing contaminant migration. Five types of caps
were evaluated in the Feasibility Study; the soil/clay type
was selected because it was as protective as any other
evaluated, and it was the most cost effective. The Remedial
Design work will include designing a specific cap to meet the
following criteria: promote drainage, minimize erosion of the
cover, and provide long-term minimization of migration of
liquids through the underlying contaminated materials.
Mine Adit and Stock Tank
The entrance to the mine will be plugged using
conventional techniques in order to protect public safety,
particularly the curious visitor who may enter the mine. The
pipe that now carries mine drainage water to the stock tank
will be removed. A new well will be installed on the land
owner’s property in the Horse Springs Coulee aquifer to
replace the stock tank as an animal water supply.
Institutional Controls
The site will be fenced to prevent people and animals from
disturbing the cap and existing monitoring wells. A
restriction or notice will be placed on the deed to the
property which restricts future disturbance of the cap. The
community will be provided notice of sampling of the low—
yield aquifer under the site, the sampling results, and the
potential for contamination, including that from naturally
occurring arsenic in the bedrock.
Groundwater Monitoring
A groundwater monitoring program will be implemented to
verify concentrations of potential contaminants, both
spatially and temporally. During the Remedial Investigation,
groundwater concentrations of contaminants exceeded human
health-based standards on a sporadic basis. A groundwater
monitoring program to meet the objective of detecting and
verifying the extent of contamination would be conducted in
two stages:
Stage 1 . Existing wells will be sampled on a quarterly basis
for two years for selected parameters to verify any changes in
contaminants of concern at the site, and whether they occur at
concentrations above cleanup standards. All existing wells
will be used in the verification analysis for cyanide,
nitrate, and nitrite, which are the groundwater contaminants
that originate only in the heap. The other contaminants of
concern, arsenic, antimony, and lead, have a probable major
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28
source in bedrock and would therefore be verified primarily in
well 3, which should have the least bedrock influence among
existing wells. If elevated levels of contaminants are not
detected, sampling frequency will be decreased to semi-
annually.
If elevated levels of contaminants are detected and
verified, a more extensive monitoring system will be
established in Stage 2 to monitor contamination at the point
of compliance and to clarify the natural bedrock component of
contamination in relation to contamination coming from on-
site sources. If elevated levels of contaminants are not
verified, Stage 2 will not be needed either for verification
of contamination or for compliance monitoring. The selected
parameters and the standard (acceptable concentration) for
each are shown in Table 7 below.
Stage 2 . The more extensive monitoring system will include the
four existing monitoring wells, three additional downgradient
wells, one additional upgradient well, and a contingency for a
fourth additional downgradient well. if required to adequately
span the flow path of groundwater at the point of compliance.
Two of the downgradient wells will, be installed at the point
of compliance established in the western margin of the Horse
Springs Coulee aquifer. A third downgradient well and an
upgradierit well will be installed to provide an adequate two-
dimensional array of monitoring points to verify the direction
of flow.
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29
Table 7. Groundwater Parameters & Standards
Concentration
Constituent at Site Standard Rationale
antimony 40 ug/l 120 ugh Health based level
arsenic 14 ugh 6 ug/i iO(-4) cancer risk
cyanide 122 ug/l 154 ug/]. Health advisory
lead 23 ug/i 20 ugh Proposed MCL
nitrate (N) 17 mg/i 10 mg/i (as N) MCL
(45 mg/i as NO 3 )
nitrite (N) 0.4 mg/i 1 mg/i (as N) Proposed MCL
(3.3 mg/i as NO 2 )
combined 17.4 mg/i 10 mg/i (as N) Proposed MCL
nitrate and
nitrite
The parameters to be used for ground water monitoring will
include the field parameters (water level, temperature, pH,
electrical conductivity, and Eh) and the parameters of concern
identified in the Remedial Investigation (total cyanide, weak
acid dissociable cyanide, arsenic, antimony, lead, nitrate,
and nitrite). The need for continued groundwater monitoring
will be evaluated during the five—year review of the site.
A statistical procedure will be used to evaluate
monitoring data for determining the spatial and temporal
trends in contaminant levels. Groundwater treatment design
would begin if the Stage 2 (point of compliance) wells show
- contamination coming from the site exceeds the standards in
Table 7 g is not the result of naturally occurring
contamination, based on statistical evaluation of all the
data.
Contingent Groundwater Treatment Proaram
If groundwater treatment is chosen as a remedial
alternative based on analyses of monitoring results,
groundwater extraction and treatment at the surface will be
employed. Potential treatment for cyanide could be chosen
from methods listed in Section 2.5.4 of the Feasibility Study
Report (EPA, Jan. 17, 1990) for treatment of rinsewater from
ieachate. Potential treatment for arsenic will employ arsenic
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30
removal by use of iron sulfate or other precipitant. In this
method of treatment, ferric sulfate is added as a floc to the
water to be treated. A high oxidation state is maintained by
aeration during treatment in order to keep iron in the ferric
form and arsenic in the arsenate form. A slightly acidic
operating pH of pH 6-7 is maintained to promote chemical
removal of arsenic from water by any of three following
processes:
1. Precipitation of ferric arsenate.
2. Coprecipitation of arsenic with ferric hydroxide.
3. Adsorption of arsenic with ferric hydroxide.
Arsenic removal is then completed by separation of sludge from
water.
As noted above, groundwater treatment would not be
implemented until the level of groundwater contamination is
verified. A design phase would also precede any groundwater
treatment to verify that groundwater extraction is practical
in the shallow aquifer. On the basis of the Remedial
Investigation, groundwater treatment is at present considered
to be an inappropriate alternative because of the low levels
of contaminants and the low hydraulic conductivity of the
shallow aquifer.
Points of Compliance
A point of compliance f or groundwater standards will be
established in the western margin of Horse Springs Coulee
aquifer 100-200 feet downgradient from the edge of the leach
heap. This point is chosen on the basis of two findings of
the Remedial Investigation:
1. The shallow aquifer beneath the heap has a very low
hydraulic conductivity on the order of 7 x 10-6 cm/s.
Such low hydraulic conductivity makes the shallow aquifer
unusable as a water supply. Horse springs Coulee aquifer,
on the other hand, is an important water supply for
irrigation and residential use. The part of Horse Springs
Coulee aquifer adjacent to the mine site is the most
appropriate point to monitor for effects of contaminants.
2. Some of the contaminants of concern (arsenic, antimony, and
lead) in the shallow aquifer have a potential natural
source in bedrock adjacent to the leach heap and mine
dump. A point of compliance in Horse Springs Coulee
aquifer, rather than the shallow aquifer, is more removed
from the potential bedrock source and will better allow
differentiation of contaminants from the mining activities
versus naturally occurring contaminants.
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31
X. STATUTORY DETERMINATIONS
The selected remedy meets statutory requirexnent of Section
121 of CERCLA, as amended by SARA, and to the extent practicable
the National Contingency Plan. The evaluation criteria are
discussed below.
1. Protection of Human Health and the Environment
The selected remedy will protect human health and the
environment by consolidating the contaminated materials onto
the leach heap; capping and covering the heap and implementing
institutional controls to minimize exposure; and monitoring
the groundwater to assure it is not affected by sources at the
site. These are all long—term measures. In the short term,
standard health and safety precautions will be taken to
protect workers; no other populations are currently at risk
from this site.
2. Attainment of ARARS
The selected remedial actions meets all identified ARARs.
These are listed below, by media. Except for the Safe
Drinking Water Act (SDWA) standards, these are all action-
specific ARARS (SDWA standards are chemical-specific) There
are no location—specific ARARs for this site.
Hazardous Waste :
RCRA. Not applicable due to mining waste exclusion (40 CFR
261.4). Not relevant and appropriate because the waste at the
Silver Mountain Mine site does not exhibit a characteristic of
hazardous waste and is not similar to a RCRA waste.
Washington Stat. Dang.rous Wast• Regulations (WAC 173-303).
Some wastes containjr g greater than 100 ppm arsenic are
regulated as dangero wastes. Although the remedial actions
planned do not constitute treatment, storage, or disposal, the
actions are sufficiently similar to make these regulations
- relevant and appropriate. Specific sections of the
regu1atjo that are relevant and appropriate include:
Section 610 Closure and Postclosuz.
Suba .ction 2a: Closure psrfornanc. standard. Must close
in a manner that: minimizes the need for further maintenance;
and controls, minimizes or eliminates to the extent nessary to
protect human health and the environment, postclosure escape
of dangerous waste, dangerous constituents, leachate,
contaminated runoff, or dangerous waste decomposition products
to the ground, surface water, groundwater, or the atmosphere;
and returns the land to the appearance and use of surrounding
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32
land areas to the degree possible given the nature f tne
previous dangerous waste activity.
Subsection 7d: Postclesure care and use of property.
Postclosure use of property on which dangerous wastes remain
after closure must never be allowed to disturb the integrity
of the final cover or any other components of any containment
system, or the function of the facility’s monitoring systems,
unless the Department finds that the disturbance is necessary
to the proposed use of the property, and will not increase the
potential hazard to human health or the environment.
Subsection lOb(i) (A) (3): Notice in deed to property.
Within sixty days of closure the owner or operator must:
record, in accordance with state law, a notation on the deed
to the property, or on some other instrument which is normally
examined during title search, that will in perpetuity notify
any potential purchaser of the property that the land has been
used to manage dangerous wastes; and that its use is
restricted as specified in subsection 7d.
Section 645, subsection 8: Groundwater monitoring
requirements.
Section 665, subsection 6: Closure and postclosure care
for landfills. This subsection contains general requirements
for a final cover, maintenance, and monitoring.
Water :
Safe Drinking Water Act, Maximum Contaminant Levels (MCLs).
An applicable requirement at the point of compliance, these
are the federal standards for drinking water supplies. MCL5
exist for several elements found at the site, including
arsenic, cadmium, lead, silver, and several others.
Minimum Standards for Construction and Maintenance of Wells
(WAC 173.160). An applicable requirement, this state of
Washington regulation addresses how wells must be installed
and abandoned by licenses well contractors. The well to be
drilled to replace the stock tank must comply with both the
administrative and substantive requirements of WAC 173.160 and
WAC 173.162, because the well will be located in the Horse
Springs Coulee aquifer, outside of the site boundaries.
State Water Pollution Control Act (RCW 90.48). This could be
applicable if groundwater treatment were conducted. This act
requires the use of all known available and reasonable methods
to prevent and control pollution of the waters of the state.
Specific substantive requirements are set forth in:
90.48.010 Policy enunciated
0
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33
90.48.020 Definitions (pollution & waters of the state)
90.48.080 Discharge of polluting matter in waters
prohibited.
Regulation of Public Ground Waters CRCW 90.44). This could be
applicable if groundwater treatment were conducted. This
chapter establishes that the “first in time, first in right”
doctrine of water appropriation applies to groundwater as well
as surface water. If the groundwater extraction system
adversely impacts either the quantity or quality of a senior
water right holder, the impacts must be mitigated.
Water Resources Act of 1971. (RCW 90.54). This could be
applicable if groundwater treatment were conducted. This act
sets forth fundamentals of water resource policy for the state
to insure that waters of the state are protected and fully
utilized for the greatest benefit to the people of the state
and, in relation thereto, to provide direction to the
Department of Ecology and other state agencies and officials,
in carrying out water and related resources programs.
Specific substantive requirements are set forth in:
90.54.020 General declaration of fundamentals for
utilization and management of waters of the state.
Establishes: beneficial uses; the basis for allocation
which includes the loss of opportunity in the equation for
maximum net benefits; base flow in perennial streams and
rivers shall be retained, and all known available and
reasonable methods of treatment shall be applied to
discharge of wastes into waters of the state.
Protection of Withdrawal Facilities Associated with Ground
Water Rights (WAC 173—150). This could be applicable if
groundwater treatment were conducted. The purpose of this
chapter is to establish and set forth the policies and
procedures of the Department of Ecology in regard to the
protection of the availability of groundwater as it pertains
to the water withdrawal facilities of holders of groundwater
rights. Particularly:
173—1.S0—0 0 Defines impairment of water rights.
173—150—0 O Voluntary agreements. Allows junior and
senior water right holders to reach a mutually satisfying
agreement regarding impairment of water supply by one of
the parties.
173—150—100 Ensures protection of water quality as well
as quantity.
Water Quality 8tandarda for Surfac. Waters of the State of
Washington (WAC 173—210). This would be applicable if
groundwater treatment were conducted and resulted.in
discharges to surface water. The purpose of this regulation
is to establish water quality standards for surface water of
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I
Silv€r Mountain Mine Mining Waste NPL Site Summary Report
Reference S
Not Concerning Damage Report and Mineral Rights;
Dennis Bowhay, Washington Department of Ecology;
July 21, 1983
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Silver Mountain Mine Mining Waste NPL Site Summary Report
Reference 6
Memorandum Concerning Neutralization
of Silver Mountain Cyanide; From Harold Porath,
Washington Department of Ecology, to John Hodgson,
Washington Department of Ecology; November 19, 1981
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/
•1
DLI AJ . T 1E’ 01 :c( ;i CY
• • ,.•,•. .t • ; •;•_• .,
Har j ?orath
SUBJECT: Nsutrajj:atjon of 5LLv r (out t.zth Cvar
ovc. be: L9, 1981.
ta - Ini 4, eZ.a .r Ubrc:ht, asr cud Ka.rol4 ?or. :,
1.U ) h ur , : ove er t3, 1931, tO look ov ptec:reg of SLiver o j
gjj 3pc?atLn pr.,c i,.jr f .,r the r%etr jj:atjon 0 ! the CY3 jje
SLiver ic p oune4 f r thc_ day. Arrae
a. ta :, been a4c to ti • p a apnr puap froii c’i City of O ak, iced
Couzi:y ?ui 1.ic Works) to be at the ine sLt t 1 t
4Jv. •3 y, 3 SEILkCS and P r.jt. thgn cr. vc •j ca St?IC Ju 1tat nine t
: d 3s ik,* :o st a ftr c ‘ an4 ‘.ook g :tic its and to f-rthgr eftu
Jp* tiofl 4 1 pL*fl fJ th* fOi1.3Vi diy.
ftr kjn tie i.ap, tra ::, eni , L.rech: nd Por c: :
La intaj 1ins 3t 3:25 hoiars, and i dj jy cleared dsbrj f: e
th site to .illow vc iicL.e a c Co the ev4uLd rcncI . Th puop
tiona L a1oe aiLs ths tren La uc a n.igc that too 3o1 &tj coeLd b
a:i4 within the trsnd . 3arrsIe and oth c debrLs were also r ooved
trench. The county wet r trii.k, drivt by Dvayna orc then zrrt,nd.
.‘ sam,la for cyae 4e anaj 7 ,j$ was co1L ct g before :he naiitr L:etjo-
s be pn. The p I vie asi at this tLg s and fo•iad to be pM s ThL pu
sai atjrtsg and chiorios m addad starti at 91.3 nours. Dry ca1ct
1orit e was mløvLy shavel.g into one end of the cya Ue aolutj, trenc ,
in front of the snetion Lntaics to the punt,. In this vs—, the ch1orj wa.
4u kL ,L into the puap and aized with the c auide solution using the actiofl
pump to z and disso lv. the chlorine. Observations of the pump 4tsc .i :; . at
ts4 ag end of the cyanide s 1ation treucI thdicate d chat the caiciuo ypo-
chlorLg 5 d ost coapletely dissOl.v.d in t1i cyanide solution.
/
_ __
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Silver Mountain Mine Mining Waste NPL Site Summary Report
Reference 7
Telephone Communication Concerning the Current Status
of the Silver Mountain Site;
From Ingrid Rosencrantz, SAIC,
to Neil Thompson, EPA Region X Remedial Project Manager;
August 9, 1990
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TELECOMMUNICATIONS
SUMMARY R ORT
SAIC Contact: Ingrid Rosenaan*z Date: 8/9/90 Time: ____
Made Call Received Call —
Person(s) Contacted (Organization): Neil Thom on, PA Region X RPM, Silver Mountain Mine,
(206) 442-1987.
Subject: Silver Mountain Mine te
Summnry: EPA Is nearing completion of the Remedial Action design phase. The RPM antiopates
having biddable documents by the end of the quarter. Construction will depend on fund financing -
it is a fund-lead project and requires the State to match funds. Construction ean be completed in
one construction season. The design addresses the entire ROD - capping through ground-water
monitoring.
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L2-7
Mining Waste NPL Site Summary Report
Smuggler Mountain
Pitkin County, Colorado
U.S. Environmental Protection Agency
Office of Solid Waste
June 21, 1991
FINAL DRAFT
Prepared by:
Science Applications International Corporation
Environmental and Health Sciences Group
7600-A Leesburg Pike
Falls Church, Virginia 22043
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0
DISCLAIMER AND ACKNOWLEDGEMENTS
The mention of company or product names is not to be considered an
endorsement by the U.S. Government or by the U.S. Environmental
Protection Agency (EPA). This document was prepared by Science
Applications International Corporation (SAIC) in partial fulfillment of
EPA Contract Number 68-W0-0025, Work Assignment Number 20.
A previous draft of this report was reviewed by Paula Schmittdial of
EPA Region VIII [ (303) 293-1527], the Remedial Project Manager for
the site, whose comments have been incorporated into the report.
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Mining Waste NPL Site Summary Report
SMUGGLER MOUNTAIN
PITKIN COUNTY, COLORADO
INTRODUCTION
The Site Summary Report for the Smuggler Mountain site is one of a series of reports on mining sites
on the National Priorities List (NPL). The reports have been prepared to support EPA’s mining
program activities. In general, these reports summarize types of environmental damages and
associated mining waste management practices at sites on (or proposed for) the NPL as of February
11, 1991 (56 Federal Reaister 5598). This summary report is based on information obtained from
EPA files and reports and on a review of the summary by the EPA Region VIII Remedial Project
Manager for this site, Paula Schmittdial.
SiTE OVERVIEW
The Smuggler Mountain site is located immediately northeast of the City of Aspen in Pitkin County,
Colorado. One hundred ten acres of waste rock, tailings, and slag (containing high levels of lead and
cadmium) comprise the site. The mining wastes that characterize the site are the result of years of
extensive mining, milling, and smelting operations. Silver, lead, and zinc mining operations were
conducted in the late 1800’s and early 1900’s. In the 1960’s, a reprocessing facility was run at the
site. Soil is the primary contaminated medium; however, contaminants have been found in ground
and surface water. The key contaminants of concern are lead, cadmium, zinc, and other heavy metals
(Reference 1, Summary of Remedial Alternative Selection, Section A).
EPA determined that the site was to be defined as those areas with surface contamination of greater
than 1,000 parts per million (ppm) lead (Reference 2, page 1-3). There are two Operable Units
designated within the site. Operable Unit 1, indicated by the bold black lines in Figure 1,
encompasses residential areas including the site repository at the Mollie Gibson Park (designated for
soil remediation). The boundaries of Operable Unit 2, the Smuggler Mine, have not yet been
established (see Figure 2) (Reference 8).
The site is within the City of Aspen, Colorado, which has a year-round population of 4,500
(Reference 1, Abstract; Reference 4, page 1). In many cases, development in the Aspen area has
taken place directly over waste piles, or waste piles have been moved to the side of developed areas
and remain as berms or mounds of contaminated soil. The site is approximately 90 percent developed
(97 percent within Operable Unit 1) as residential housing (Reference 3, page 2; Reference 4,
1
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Smuggler Mountain
s:1’ , Lzf l7 I
10 TTY t13. 5 (7 1 CZLI.—
— — —
I
/ f7fl?r ra?
/ 02 ? ‘Z LJ
I
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/
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0•
—
— S
FIGURE 1. SMUGGLER MOUNTAIN SITE VICINITY MAP
S
S
‘4
I
—. S
w
• t trrs — - szrr
rUTW ‘ t L4
2
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Mining Waste NPL Site Summary Report
Ss.i.s: CDM I•sS
SC.S.: 1 — S•e.
FIGURE 2. PRESENT SITE FEATURES
N
C.
S
0
•Sii
ASPEN
3
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Smuggler Mountain
page 1). The residential properties consist of two large condominium complexes, two mobile home
parks, several small condominium developments (4 to 12 units), approximately 25 to 30 homes, and a
tennis club (see Figure 1) (Reference 4, page 1; Reference 1, Summary of Remedial Alternative
Selection, Section A).
EPA added the site to NPL in May 1986. The Operable Unit 1 Remedial Investigation/Feasibility
Study was completed by the Potentially Responsible Party (PRP) in early 1986 and amended by EPA
in the same year. Using the Remedial Investigation data, EPA prepared an Endangerment
Assessment. The Superfund Enforcement Decision Document, signed on September 29, 1986,
describes the remedial actions to be taken at the site (Reference 1, Abstract and Cover
Memorandum). Subsequent sampling (in 1988) prompted EPA to change the selected remedy for
Operable Unit 1 and postpone re-evaluating the remedy for Operable Unit 2 until a Remedial
Investigation/Feasibility Study was completed (Reference 3, page 5).
OPERATING HISTORY
In the late 1800’s and early 1900’s, mining companies ran extensive silver, lead, and zinc mining,
milling, and smelting operations onsite. Although several small operations started and stopped after
1930, records indicate that the bulk of the mining wastes at the site were placed on the steep slope of
the western side of Smuggler Mountain near the Smuggler shaft from 1880 to 1915. In the mid-
1960’s, a reprocessing facility was run on the site, causing the dispersion of the wastes from the
relatively distinct piles at the mine shaft to other locations throughout the site. Also, a number of
settling ponds were created around the site during reprocessing. The wastes were dispersed further
by subsequent residential development (Reference 1, Site History, Section B; Reference 2, page 2-1).
Mine wastes, such as waste rock, tailings, and slag, comprise much of the site. It is estimated that
approximately 2.4 million cubic yards of these waste materials were generated at the site; however,
volume estimates are uncertain and have been difficult to determine (Reference 5, page 2-3). The
wastes have been spread over a wide area and at depths varying from 1 or 2 to 40 feet. They occur
covered, uncovered, or mixed with native soil, and they contain high concentrations of lead and
cadmium, among other constituents (Reference 1, Site History, Section B; Reference 5, pages 2-1, 2-
3, and 2-6).
SITE CHARACTERIZATION
Soils, surface water and sediments, ground water, and air at the site were sampled by the PRPs and
EPA to define the extent of contamination. The site is characterized by high concentrations of lead,
cadmium, and zinc, as well as elevated concentrations of arsenic, barium, copper, manganese, silver,
4
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Mining Waste NPL Site Summary Report
and mercury (found in tailings and other mining wastes). Tables 2 through 9 in the attached
Reference 1 present the concentration levels of these and other constituents in each medium
(Reference 1, Current Site Status, Section C). The following sections characterize each medium
(soils, surface water, sediments, ground water, and air). According to EPA Region Vifi, the
available air, ground-water, and surface-water data has not provided a complete characterization of
contamination for those media.
The site, for purposes of action under the Comprehensive Environmental Response, Compensation,
and Liability Act (CERCLA), was defined as those areas having surface contamination of lead at
concentrations over 1,000 ppm. Figure 1 outlines the most recent site boundary determined by
extensive surface and subsurface soil sampling and testing. Soil-sample analyses indicated that all
tailings materials, or materials which contained mine tailings, had levels greater than EPA’s action
level of 1,000 ppm (Reference 2, page 1-3; Reference 3, page 4).
Several soil sampling projects have been completed. Sampling was conducted downslope from the
tailings piles in 1983 by Ecology and Environment. Results found elevated levels of arsenic, barium,
cadmium, copper, lead, manganese, and zinc (levels not provided) (Reference 2, page 2-6).
Four soil types were sampled during the 1986 Remedial Investigation/Feasibility Study:
• Mine Tailin2s - By-products of Smuggler silver/lead mine operations
• Man-made Fill - Material used as fill that contains some mine tailings usually identified by its
gray to black color
• fiji - Soil used as fill, which may include dirt, stone, brick, slag, glass, etc., but does not
contain mine tailings
• Native Soil - Undisturbed, natural soil varying from alluvial terrace deposits to glacial drift
and colluvium.
Both mine tailings and man-made fill were considered to be contaminated with lead at concentrations
greater than 1,000 ppm. Each sample of fill and native soil had lead levels below 1,000 ppm
(Reference 1, Current Site Status, Section C; Reference 2, pages 1-3, 3-5, and 3-6). The average
5
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Smuggler Mountain
lead values for surface samples and subsurface samples collected for the 1986 Remedial
InvestigationlFeasibiity Study are presented in Table I below (Reference 2, page 4-13).
TABLE 1. AVERAGE LEAD CONCENTRATIONS IN SOILS
Surface
(in ppm)
Subsurface
(in ppm)
Mine Tailings
10,477
7,923
Man-made Fill
—
2,985
Fill
546
520
Native Soil
443
452
Cadmium is also of concern due to its toxicity. Laboratory analyses showed that all samples with a
high lead content also contained significant amounts of cadmium; samples that exhibited low lead also
exhibited low cadmium (Reference 2, pages 5-1 and 5-2).
According to EPA Region Vifi, 1,000 soil samples were collected from various depths (the surface to
approximately 4 feet) in the residential and commercial areas built on tailings in 1988. The samples
were analyzed using X-ray Fluorescence (XRF). However, the most extensive soils sampling
program took place in 1990. At that time, over 3,300 samples were collected from over 1,100
sample locations. Three samples were extracted from each location at defined depths: 0 to 2 inches,
2 to 6 inches, and 6 to 12 inches. XRF was used to analyze the samples for lead. Soil lead
concentrations were found to range from 0 to 107,000 ppm. The geometric mean of all lead samples
collected during the 1990 sampling was 6,577 ppm. Table 2 provides a percentage breakdown by
lead concentration of all samples collected in 1990 (Reference 8).
6
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Mining Waste NPL Site Summary Report
TABLE 2. LEAD CONCENTRATIONS IN SOILS
PERCENTAGE OF SAMPLES BY CONCENTRATION
RANGE
Lead Concentration
(in ppm)
Percentage of Samples
0-500
49
500-1,000
16
> 1,000
35
Surface Water and Sediments
The Roaring Fork River is approximately 1,000 feet downgradient to the southwest of the site. There
are no major, natural drainage channels crossing the site; however, two small- to moderate-sized
basins located to the east and northeast affect site drainage. Hunter Creek (see Figure 2) passes
approximately 500 feet to the north of the site. The Salvation Ditch (see Figure 1), an irrigation
canal, surfaces on the northern part of the site from a buried pipe. Drainage at the site occurs largely
as runoff although channelization of mine-drainage water, such as from the Mollie Gibson Mine shaft
and the Cowenhoven Tunnel, which both traverse the site, is apparent (see Figure 2).
Samples taken in 1983 showed that Total Dissolved Solid (TDS) concentrations ranged from 540
milligrams per liter (mg/I) for the Mollie Gibson drainage to 918 mg/I for the Cowenhoven Tunnel
(which discharge to the Roaring Fork River and Hunter Creek, respectively) (Reference 2, page 2-4).
Roaring Fork River was sampled in 1983, and barium, iron, manganese, and zinc were detected at
levels within the compliance range for Federal and State ambient water quality standards. Stream
sediments were also sampled. Based on the available data, it was concluded in the Enforcement
Decisidn Document that onsite contaminants were not mobile enough to cause a substantial increase in
the levels of metals in surface water and surface-water sediments (Reference 1, Current Site Status,
Section C). Results of the Remedial Investigation indicated that the existing surface-water system,
including Cowenhoven and Mollie Gibson drainages, Hunter Creek, and the Roaring Fork River, has
not been contaminated by onsite tailings (Reference 6, page 21).
Although the Enforcement Decision Document’s abstract mentioned that the City of Aspen obtains
drinking water from surface waters in the area, no further mention was made of drinking-water
sources, and no indication was given of any associated concern. This is most likely because surface-
7
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Smuggler Mountain
water samples were within Federal and State standards for the metals of concern (Reference 1,
Abstract).
Ground Water
Ground water beneath the Smuggler site occurs in both unconsolidated surficial deposits and within
the underlying sedimentary bedrock strata. The bedrock has extensive faulting and fracturing, which
control the occurrence and flow of ground water in undisturbed strata. It is likely that the ground-
water flow within the aquifers is also complicated by underground mine workings. The bedrock
ground-water system is not of great concern because of the limited existing and potential future use.
Current water resources are from the alluvial aquifer of the Roaring Fork River Valley; the only
concern relative to the aquifer underlying the site is whether it recharges the alluvial aquifer. Based
on existing knowledge of the site, the alluvial system recharge is provided from the Cowenhoven and
Mollie Gibson adits, not the bedrock ground-water system (Reference 6, page 11).
The unconsolidated surficial aquifer is in direct communication with the ground water in the alluvium
of the Roaring Fork Valley and is, therefore, of greater concern than the bedrock ground water
(Reference 6, pages 11 and 12). Investigations indicate that there is no alluvial ground-water system
underneath the tailings at the site (Reference 2, page 2-4).
Prior to 1985, contamination was found in private wells drawing from the alluvial aquifer; however,
it could not be determined if it resulted from the natural condition of the nearby bedrock, the heavy
metal-laden tailings at the Smuggler site, or (as alleged by some PRPs) the lead solder in the water
pipes. A 1985 Focused Feasibility Study (focusing on ground-water contamination) concluded that
the risk associated with the ground-water medium was moderate. However, largely insoluble heavy
metals may be leached by infiltrating rainfall, and the ground water could contribute to the
contamination of surface water through the interface between alluvial ground water and the surface
waters in the Roaring Fork River and Hunter Creek (Reference 5, pages 3-2 and 3-4).
Concern over the contamination of ground water onsite and offsite from tailings leachate was
expressed in the 1986 Remedial Investigation/Feasibility Study. However, acid/base balance studies
determined that the buffering capacity of the natural soils would most likely prevent acid mine
drainage problems (Reference 2, page 1-4).
Seven existing private wells and eight newly installed monitoring wells were sampled between 1983
and 1986. The potential ground-water problem was indicated by elevated levels of cadmium, zinc,
uranium, and gross alpha. Elevated levels of cadmium were noted in two private wells and two EPA
8
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Mining Waste NPL Site Summary Report
monitoring wells. Cadmium in one EPA monitoring well was near EPA’s Maximum Contaminant
Level (MCL) of 0.01 mg/I. Uranium and gross alpha were found to be elevated in two monitoring
wells, and zinc concentrations were highest in a private well. PRPs have postulated that despite the
abundance of calcium carbonate in the host rock, leaching could occur m localized pockets of
mineralized materials if derived from the core of the mineralized zone. Results indicated that lead
and arsenic are not ground-water contaminants (Reference 1, Current Site Status, Section C).
During the Remedial Investigation/Feasibility Study, selected ground-water samples were analyzed for
radium-226, gross alpha, and uranium because of the potential for elevated concentrations of
radioactivity. Results indicate that gross alpha concentrations do not exceed MCLs under the Safe
Drinking Water Act [ set at 15 pico Curies per liter (pCi/I)]. Uranium values, however, exceed the
Colorado guidance level of 10 pCi/I (about 0.015 mg/I) (see Table 3). In addition, samples in two
wells were found to have substantially high levels of uranium and gross alpha, which is consistent
with the wells showing higher TDS and trace-metaj concentrations. Because radioactivity appears to
be associated only with the tailings, it is believed that leaching of tailings is occurring (Reference 6,
Table 1). It was recommended in the Addendum to the Remedial Investigation/Feasibility Study that
monitoring for radionuclides should continue (Reference 6, pages 12 through 15).
Air
Air samples were taken from onsite and background locations in 1985. Levels of arsenic, cadmium,
lead, and zinc in the air onsite were elevated as compared to background. Only cadmium and arsenic
were found to be present at levels above the proposed National Emissions Standards for Hazardous
Air Pollutants (Reference 1, Current Site Status, Section C). No additional information was provided
in the references concerning air quality.
ENVIRONMENT DAMAGES AND RISKS
The site was first identified in 1981 when research into crop uptake of trace metals indicated a
potentially serious problem with the uptake of lead and cadmium by vegetables grown on regraded
mine and mill tailings (Reference 7, page 1).
Presently, the potential for human exposure exists through direct contact of soils and inhalation of
contamirnint-laden dusts by people onsite as well as those in nearby residential areas. The risk of
ingesting drinking water ccntaniinated by site soils also exists, although due to site conditions (i.e.,
soil and pollutant characteristics), the potential for exposure is significantly reduced (Reference 2,
page 5-2).
9
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Smuggler Mountain
TABLE 3. GROUND-WATER ANALYSES FOR FEBRUARY 1986
Well Number
Parameter
Units
GW-1_ [ _GW-S
GW-7
GW-8
GW-9
GW-1O
Arsenic
mg/I
ND
Dry
ND
ND
ND
ND
Cadmium
mg/I
ND
Dry
0.010
ND
ND
ND
Calcium
mg/I
46.5
Dry
168.0
22.3
120.0
136.0
Iron
mg/I
0.034
Dry
0.121
0.026
0.022
0.086
Lead
mg/I
ND
Dry
ND
ND
ND
ND
Magnesium
mg/I
14.5
Dry
53.9
6.2
41.2
39.5
Manganese
mg/I
0.025
Dry
0.226
0.05
ND
0.174
Potassium
mg/I
0.95
Dry
2.43
ND
1.49
1.64
Sodium
mg/I
19.4
Dry
4.95
0.93
3.97
6.19
Zinc
mg/I
0.020
Dry
1.44
0.065
0.460
0.066
Oil and Grease
mg/I
1.1
Dry
2.2
1.4
ND
ND
TOC
mg/I
15.0
Dry
2.1
46
4.9
1.7
Chloride
mg/I
29.0
Dry
ND
ND
ND
30.0
Sulfate
mg/I
111.0
Dry
215.0
30.0
313.0
220.0
Bicarbonate
mg/I
54.0
Dry
180.0
49.0
162.0
199.0
TDS
mg/I
280.0
Dry
905.0
95.0
625.0
625.0
Radium-226
pCi/I
0.04 ±
0.02
Dry
0.45 ±
0.02
0.21 ±
0.01
0.34 ±
0.02a
0.37 ±
0.02
GrossA lpha
Pci/I
3.0
Dry
140.0
4.0
120.0
17.0
Uranium mg/I 0.0024 Dry 0.310 0.00021 0.230w 0.036
Validation criteria qualifiers pertain to some data and are included in REM II files.
• Duplicate values:
• Radium-236 0.36±0.02
• Gross alpha 100
• Uranium 0.210
Source: CDM, 1986
10
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Mining Waste NFL Site Summary Report
Lead and cadmium are the two metals of most concern at the site due to their elevated concentrations
at the site and acute toxicities. Lead exposure is of specific concern to children, who have the
greatest risk of exposure through soil ingestion and a greater susceptibility to blood lead poisoning. It
should be noted that toxic effects of lead ingestion in children from lead-based paints (i.e., elevated
blood levels) have been documented, but exposure to lead in tailings and soil such as those at the
Smuggler site has not been documented (Reference 2, page 2-7).
Cadmium can also be acutely toxic, and cadmium compounds are generally more bioavailable than
lead compounds. A ground-water sample in one well at the site (on one occasion) had a cadmium
concentration of 13 micrograms per liter (jig/i), which exceeded the ambient water quality standard of
10 ig/l. The well was checked again and found to be less than 10 ig/l (Reference 2, page 2-7).
Studies have also shown that cadmium may be carcinogenic to humans, has chronic effects on the
kidneys, and may affect human reproduction. Plants, including leafy green vegetables and root crops,
are subject to uptake of cadmium from contaminated soils. Ingestion of such vegetables may cause
exposure of humans to cadmium (Reference 4, page 2).
The metals found at the site are relatively insoluble due to the relatively neutral pH (6.38 to 7.22) of
the tailings, soil, and bedrock materials. The insolubility of the metals decreases their bioavailability
and, therefore, their toxicity (Reference 2, pages 2-7 and 2-8).
REMEDIAL ACTIONS AND COSTS
The Smuggler Mountain site was added to the NPL in May 1986. The Enforcement Decision
Document describing the final remedial action for Operable Unit 1 was signed on September 29,
1986. There are two Operable Units: (1) residential areas, including the site of a repository at the
Mollie Gibson Park; and (2) the Smuggler Mine site. The remedy for the first Operable Unit, as
decided in 1986, was separated into 5 components: (1) source isolation of high-lead wastes;
(2) source isolation of low-lead wastes; (3) increased ground-water monitoring; (4) alternative water
supply; and (5) operation and maintenance of low- and high-lead waste caps. The remedy for
Operable Unit 2 is mine reclamation and possible ground-water corrective action (Reference 1, Cover
Memorandum).
During the design of the remedy presented in the 1986 Decision Document, additional soil sampling
was conducted to determine the necessary capacity for the onsite repository. The results of this
sampling, which was conducted in 1988, indicated that the remedy selected in 1986 for Operable Unit
1 needed to be changed because it was unreasonable to separate remediation by level of
11
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Smuggler Mountain
contamination, as the levels were so interspersed. According to EPA Region VIII, in 1990,
additional sampling was conducted to determine final design requirements. The final remedial actions
to be conducted at the site, decided in 1990, are presented below (Reference 3, pages 2, 3, and 5;
Reference 4, pages 1 and 2).
The revised remedy consists of four major elements: (1) onsite repositories; (2) clean-up of
individual residential properties; (3) remedial action at Hunter Creek & Centennial Condominiums;
and (4) institutional controls. In general, the minimum requirements for the site remedy are that the
top 1 foot of soil must not show lead contamination levels greater than 1,000 ppm, and that there is a
healthy vegetative cover, a paved driving area, raised garden beds, and limited access under homes,
decks, and similar structures (Reference 3, pages 5 through 12).
Onsite Reoository
Two onsite repositories will be constructed to serve as the primary locations for disposal of
contaminated soil/tailings excavated during the residential clean-up. These repositories will be located
at the Racquet Club (with a design capacity of 9,000 cubic yards) and the Mollie Gibson Park site
(with a design capacity of 45,000 cubic yards) (Reference 8). The park repository will also serve as
the “open” repository for disposal of contaminated soil/tailings displaced due to property development
within the site boundary subsequent to clean-up. The Salvation Ditch irrigation pipeline (see Figure
1), which passes through the Mollie Gibson Park site, is currently being relocated to accommodate the
repository. Additionally, the clean fill and topsoil used as cap material for the repository will have
lead concentrations of 250 ppm or less. The Smuggler Racquet Club property is the proposed
location of this repository (Reference 3, pages 5 through 7).
Clean-up on Individual Residential Pronerties
Properties with soil lead concentrations above 1,000 ppm will be fully remediated using a geo-textile
liner covered with foot of clean fill and topsoil and a vegetative cover to minimize erosion. The geo-
textile liner is used to prevent mixing of the contaminated materials with the clean fill. Properties
with soil-lead concentrations of less than 1,000 ppm may require some remedial action to meet the
minimum requirements of the remedy as described above (Reference 3, pages 7 through 9).
12
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Mining Waste NPL Site Summary Report
Remedial Action at Hunter Creek and Centennial Condominiums
The proposed remedy at the condominiums is similar to the remedy for the individual properties,
except that 6 inches of clean topsoil and a vegetative cover will be required to minimize erosion for
all areas not paved or covered by permanent structures. A geo-textile liner covered with 1 foot of
clean soil will be required for all existing (and any new) play areas because of the threat of lead
exposure to children. One foot of clean sand over the geo-textile liner and the 1-foot soil cover may
be substituted for a vegetative cover (Reference 3, pages 9 and 10).
Institutional Controls
“institutional Controls” refers to administrative requirements adopted by governing bodies to require
or prohibit certain types of activities. In this case, they will include various measures to maintain the
integrity of the soil and vegetative cover. For example, notices to future owners of properties on the
site will advise them of the need to maintain the vegetative cover on their property. County
ordinances can also serve as institutional controls (Reference 3, pages 10 through 12).
For Operable Unit 2, the 1986 decision listed mine reclamation and ground-water remediation as the
remedies. The final decision for Operable Unit 2 requires completion of a Remedial Investigationl
Feasibility Study to characterize the wastes and determine the appropriate extent of the remedy at the
Smuggler Mine Site in accordance with the National Contingency Plan (Reference 1; Reference 4).
Note that in the 1985 Focused Feasibility Study, a preferred action for ground-water remediation was
presented. This included criteria for technical effectiveness, safety, and public acceptance. In the
1990 remedy, however, ground-water remediation was excluded from the remedy for Operable Unit
1. It is expected that ground-water remediation will be included in the remedial action for Operable
Unit 2, subsequent to completion of the Remedial Investigation/Feasibility Study (Reference 5, page
1-3; Reference 3). In the 1990 remedy, the estimated cost of site remediation is $7.2 million
(Reference 4, page 15).
13
-------
Smuggler Mountain
CURRENT STATUS
Operable Unit 1 is presently in the Remedial Design/Remedial Action phase of clean-up. Extensive
soil sampling was conducted to identify the percent of lead in the soil. The design team is working
with homeowners on remediation. Of 160 residents, 158 have voluntarily participated in EPA’s
plans. A demonstration project, including the remediation of soil at approximately nine homes, was
to begin in mid-July 1990, to demonstrate how EPA would remediate the soils. The project was
modified because Pitkin County would not allow access to the disposal site until a Consent Decree
was established; however, EPA was able to conduct the demonstration project on two properties in
September and October 1990. The completion of the Salvation Ditch irrigation pipeline relocation
project is scheduled for June 1, 1991. Further work on Operable Unit 2 has not yet been scheduled
(Reference 8).
14
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Mining Waste NPL Site Summary Report
REFERENCES
1. Superfund Enforcement Decision Document: Smuggler Mountain Co., EPAJRODIRO2-86/037;
EPA; September 1986.
2. Remedial Investigation/Feasibility Study, Smuggler Mountain Site; Fred C. Hart Associates, Inc.;
March 1986.
3. Soil Clean-up of Smuggler Mountain Site, Aspen-Pitkin County, Colorado, Explanation of
Significant Differences; EPA Region VIII; March 1989.
4. Soil Clean-up of Smuggler Mountain Site, Aspen-Pitkm County, Colorado, Explanation of
Significant Differences; EPA Region VIII; May 16, 1990.
5. Focused Feasibility Study for Ground-water Remediation, Smuggler Site, Aspen, Colorado; Fred
C. Hart Associates, Inc.; July 5, 1985.
6. Addendum - Remedial Investigation/Feasibility Study, Smuggler Mountain, Colorado, Document
No. 149-WP1-RT-CMYB-1; Prepared for EPA; Undated.
7. Potential Hazardous Waste Site Identification and Preliminary Assessment, Smuggler Mine Site;
EPA Region VIII; March 31, 1984.
8. Personal Communication Concerning Smuggler Mountain; From Laurie Lamb, SAIC, to Bob
Elkington, EPA Region Vifi; May 10, 1991.
15
-------
Smuggler Mountain
BIBLIOGRAPHY
EPA. Superfund Enforcement Decision Document: Smuggler Mountain Co.,
EPAIROD/R02-86/037. September 1986.
EPA Region Vifi. Potential Hazardous Waste Site Identification and Preliminary Assessment,
Smuggler Mine Site. March 31, 1984.
EPA Region Vifi. Soil Clean-up of Smuggler Mountain Site, Aspen-Pitkin County, Colorado,
Explanation of Significant Differences. March 1989.
EPA Region Vifi. Soil Clean-up of Smuggler Mountain Site, Aspen-Pitkin County, Colorado,
Explanation of Significant Differences. May 16, 1990.
Fred C. Hart Associates, Inc. Focused Feasibility Study for Ground-water Remediation, Smuggler
Site, Aspen, Colorado. July 5, 1985.
Fred C. Hart Associates, Inc. Remedial Investigation/Feasibility Study, Smuggler Mountain Site.
March 1986.
Lamb, Laurie (SAIC). Personal Communication Concerning Smuggler Mountain to Bob Elkington,
EPA Region VIII. May 10, 1991.
Prepared for EPA. Addendum - Remedial Investigation/Feasibility Study, Smuggler Mountain,
Colorado, Document No. 149-WP1-RT-CMYB-1. Undated.
16
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Smuggler Mountain Mining Waste NPL Site Summary Report
Reference 1
Excerpts From Superfund Enforcement Decision Document:
Smuggler Mountain Co., EPAIROD/R02-86/037;
EPA; September 1986
-------
LVI.d S’s
Ei w t P * on
Offi oI
EPh OO,RO2 ee c
EPA
Supertund
Enforcement Decision Document:
Smuggler Mountain, CO
&
-------
I uPv.1- Q.
EPA/ROD/R08 —86/00 5
j TITj. 5 AND $USt1Y
ENFORCEMENT DECISION OOC(JMENT
Smuggler Mountain, Co
7 a1MOC($) -
TEC$NICA 5IPQ y DATA
‘ fl IAS 4Cl1 ZR PWv o m.nm j
12.
iIaPOaMU.G e DANlzATtO u *ws a.se aDoNs I0 moo *aa ii ,.i. .,
II
I
13 SPONSOaINO AQINCY NAMS AND £O0 IU ‘3 ?V QP m5p *N CO i .e
(J.S. Environmental Protection Agency
n
401 M Street, S.W.
Washington, D.C. 20460
800/00
IS $UP’I.IMIN?Aav NO?U$
is * &cy
The Smuggler MOuntain site is located is aediately northeast of the City of Aspen -
Pitkin County, CO. It comprises 110 acres of waste rock, tailings, and slag contaLrt
high levels of iead and cadmium. The site is in close proximity of Aspen, CO WhIC. as
a year—round population of 4,500. In many cases, development in the Aspen area as
taken place directly over waste piles, or waste piles have been moved to the sides :f
developed areas and remain as berms or mounds of contaminated soil. Portions of
contaminated soil have also been used for fill in some areas. The City of Aspen O 3
drinking water from surface waters in the area. The Roaring Porice River passes t e s.
approximately 1,000 feet downgradient to the southwest, and is the nearest surface
water. The mining wastes which characterize the site are the result of years of
extensive mining, milling and smelting operations. As a result, wastes are highly
dspersed, and little s known about their disposition. Soil is the primary
contaminated medium: however, contaminants have been detected in some ground and s..rf a:
waters.
The selected remedial action for the site is broken into two distinct operable
units. Operable tnit 1 — excavation and permanent onsite disposal of soils with ea
above 5,000 ppm, including a RC*A multi—layer cap; soil capping of all areas
between 1,000 and 5,000 ppm lead: five—year ground water monitoring: and provision of i
(S.. APPAfPI. 4
IV COS £ O OOC SN? £N* ’$s$
DU iP?O $
a OUN?I 5s($. 0P 5 ,q (‘sO(Q timw$
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—
Enforcement Decis3on Doc nt
Smuggler Mountain, CO
Contaminated Media: soil, qw
ey contaminants: heavy metals, lead,
cadmium, zinc
fIL] sT sss.jioN $?ATSNIIeT
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-------
EPk/ROO/R08—86/005
Smuggler Mot ta fl. CO
L6. A TR?CT (cont .nu.4)
p.rm&n. t aiternata water iupply for 5—7 resa.d.ncea. Op.rabl. — supplSm1
RI/VS. w .th possible groi. 4 water rsmsd.iation and in rsc1amat on
Eatz tsd capital cost of tha remedy is 11.816.550 vath annual O&?I of $30,900.
-------
UNITED STATES &acNM N r • I N
REGION VIII
ONE 0ENVER ACE — 999 18TH STREET — SUITE 1300
1vER. COLORADO 80202.2413
ENFORCE1 ENT DECISION DC T
RENEDIM. ALTERNATIVE 5 .WTIO
SITE
Smug ler MCuflt.aifl
p,t ccjnty, Colorado
ctjr. EM rs REVtEWE )
I am basing decision primarily on the following docim ents descrloing
the analysis of the cost and effectiveness of IIIMd lal alternatives for the
Sr g1er Mountain Site:
-SimIggler Mountain R edial Investigation/Feaslblity Study
Fred C. ttrt Associates; March l 86
-Smuggler Mountain Endangerment Assesszent
Clement Associates, May 1986
-Smuggler Mountain Focused Feasloility Study
Fred C. )Irt Associates, July 1985
‘Smuggler Mountain Addendi to Remeaial Invest1gatien/Feasio1l y Stuoy
Camp, Dresser and Mckee, May 1986
-minter Creek Soils Investigations and Corrective Measure Recoomendations
Engineering Science, 1985
-Finial Technical Oversight Report, ?ctivlties i1/84 3/86, for the
Smuggler ‘,ountain Site
Camp, Dresser and Mckee, august, 1906
- Issues stract for Smaggler Mountain Enforcement Decision Doci ent,
Cleemens, Sept er 1986
DESCRIPTION OF R DY
I have carefully reviewed and considered l1 the Information, the
alternatives analysis, and the puolic c1 nts pertaining to the selection of
a remedy for the Smuggler Mountain Site. Based on ‘ review, I have
determined that the following actions at the Smuggler Mountain Site will
effectively mitigate and minimize demags to and provide acceptable protection
of the public health, welfare, and the envirorEent. This determination is
made by the Regional A lnistrstor of Region VIII consistent with the
delegation of authority for remi4y selection dated Msy 6, 1986.
-------
The selected alternative is separated into O Operable Vfl1t The first
operable unit addresSeS the Smuggler site and does not re ation
of the actual Smuggler Mine portion of the site. A second oP abe unit W I 11
address the mine reclamation wore and will consider grouna’ . ace. ator
response actions If the results of ground water monitoring during •Jm first
operable unit indicate that such actions are appropriate.
Operable Urtit 1 - Site Rmne4y. :
A. Source Isolation of High-Level Wastes.
Create an on—site repository on County-owed property to per anent 1y
dispose of the high-level wastes (over 5,000 ppm lean) excavated t the
site. The repository will be under the perpetual care of a permanent
entity. Pltkln County, to assure the permanent disposition of the
contaminants. Consolidate all4ilgh level wastes from the site (XCl dj g
the mine site) In the repository. Cap the repository with a altl -lay,r
stable cap that ets RA performance standards for In—place closure
(40 CFR Part 264, Subpart N).
B. Source Isolation of Low-Level Wastes.
Isolate all low—level wastes (defined as areas with soil lead
• concentrations of be een 1,000 and 5.000 pp. lead) capping in place
wIth 6-12 Inches of clean topsoil and revegetatlng.
C. Increase Ground-Water Monitoring.
Monitor ground water quarterjy on-site for a period of five (5) years to
determine efficacy of the caps In enhancing ground-water quality.
arterly reports to A will describe the results of monitoring and note
any trends observed. Monitoring results and reports will be usd to
determine If further response actions are required.
0. Alternate Water Simply.
Provide a permanent, alternate, water supply ‘ closing ground-water
wells for 5—7 resIdences and connecting the residences to the existing
public water supply.
E. Operation and Maintenance of Law- and II1gh -Lvel a3te Caps.
Periodically Inspect caps to note and repair are’ deterioration,
disturbance, or discontimilty to prevent cap failure. Weekly inspections
are anticipated during the first year. Bimonthly inspections Will take
place for the second year. After o years, Inspections will be
conducted monthly. From the beginning of the fourth year, quarterly
Inspections will be conducted for the next twenty-sIx years.
Operable tk 1t 2 - Mine Reclatlofl and Possible Ground-Water Corrective Action :
A. Mdends to Redial Investigation and Feasibility Study (RI/FS).
M addendi to the existing RI/FS will be prepared to characterize the
nature and extent of contamination and determine the appropriate extent
of easdy at the S.aggler - raflt Mine site. This addsndia will be
-------
ep red in accordance with the National Contingency Plan. The Stm ggler r’ ine
J/FS will be subject to public ccc ent prior to selection of a remedy.
B. Possible Ground-Water Corrective Action.
Current water quality data do not justify action, and ground.. r
conditions are expected to Improve after Operable unit one Is
ftaplemented. However, ground-water monitoring resulta from the first
operable unit will- be used to determine if ground-water response actions
need to be Implemented. This determination will be made In a subsequent
decision document.
C. Performance of Reme4y.
Perform remedy as approved by EPA In a subsequent decision document.
Such reme4y will Include reclamation of the mine site and, If determined
to be necessary, ground-water corrective action.
DECLA RAIl ONS
Consistent with the Compr hensfve Environesntal Response, Compensation,
and Liability Act of 1980 (CE LA), 42 U.S.C. section 9601 et q., and the
hatlonal Contingency Plan (40 C.F.R. Part 300), I have dets iijj that the
selected reme4y at Smuggler Mountain Is cost-effective and consistent with a
permanent remedy that provides adequate protection of public health, welfare,
and the envlrormsnt. I also have determined that the action being taken is a
cost-effective 11 ternative n compared to the other remedial options
dewed. The State of Colorado has been consulted on the selected r dy.
.e action will require future operation and maintenance activities to ensure
the continued effectiveness of the remedy. These activities will be
considered part of the approved action. EPA has not reached agrent with
the responsible parties at the site to implement the selected remedy.
Ground water quality will continue to be monitored on site. Subsequent
response action will be considered if the monitoring shows Increasing
contamination.
The EPA or the potentially responsible parties for the Smuggler-Ourant
Mine area of the site will conduct an additional RZ/FS to further characterize
the extent of contamination at that portion of the site, and will undertake
further response actions as determined to be necessary by A in a subsequent
decision dociasnt.
_____________ L/O(
Regional Adel ni strator
Region VIII
•LO SI Q 29, 1986
1
-------
SU14’ .ARY OF REI ZDIAL. ALTERNATIVE SELE TLQN
A. SITE LOCATION AND DESCRIPTION
The Smuggler Mountain Site is located lirrediately northeast of the City of
Aspen in Pltkin County, colorado. Th. location of the site is 5how on
Figure 1. Beginn1 ng with the old Smuggler- jrant mine workings located high
on the steep slope of the western side of Smuggler Mountain, the site grades
1 nto the gentler si opes and terraces to the west-southwest towar the ci t .
Present site features are shown on Figure 2. Site elevation ranges from 7,930
to 8,lt.O feet above mean sea level. The site has been significantly altered
over the years by extensive coolDercial and residential development. Mine
wastes, such as waste rock, tailings, and slag, comprise much of the site.
The wastes occur either covered, uncovered, or mixed with nitive soil and
contain high levels of minerals containing lead and ca i a, ng other
constituents. Through the Endangerment Assessment (EA) process, A has
established a site boundary based upon a 1,000 millIgrams per kilogram (mg/kg)
or parts per million (ppm) soi1’contamination level in soils and mine wastes.
This action level has been concurred upon by the Agency for Toxic Substances
anø Disease Registry (ATSOR) in their letter to EPA Region VIII of
September 11, 1985. The State had recomo.nded an action level of 500 ppm
lead, but such a level was detrmined.by ATSDk not to be appropriate.
.ACcordingly, the llU-acrs sits is defined by a 1,000 ppm lead isopleth which
is shown on Figure 3.
The site is in close proximity to the resort city of Aspen which has a year-
round population of 4,500. Consequently, the site is comprised of both
developed and undeveloped properties. In marw cases, development has taken
place i ediately on top of waste piles, or such piles have been moved to the
slots of developed areas and remain as berms or mounds of contaminateø soil.
Portions of the contaminated soil have been excavated, used for fill, or
otherwise disturbed by grading, significantly altering the topograpt y of the
site over the years.
The Roaring Fork River passes the site approximately 1,000 feet downgradient
to the southwest. Site drainage occurs largely as surface runoff with
channelizatlon from mine discharge water (the Mollie 1bson Mine Shaft
discharges to the Roaring Fork River, and the Cowenhoven Tunnel discharges to
Hunter Creek). Drainage Is also affected ‘ o moderately sized basins:
Ptinter Creek to the north; and the Salvitlon Irrigation ditch, which
transverses the site at an elevation of approximately 8,000 feet. The ground-
water systam at the 5.ugglier site Is complex and not clearly defined. Ground
water has been found to be present in both the sedimentary bedrock and In the
unconsolidated murflclal deposits. Flow In the sedimentary bedrock is
characterized by secondary permeability, I • c. fractures and fault systems.
Current ground’water use in the area Is limited to some private wells that tap
the alluvial aquifer of the Roaring Fork River Valley. The City of Aspen does
not use the alluvial aquifer but uses surface water from other sources.
Accordingly, the Importance of the bydrology of the underlying sedimentary
strata is restricted to Its role in recharging the Roaring Fork alluvial
System.
-------
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. fl i jI f
The rnirnng wastes wi Ch Characterize the site are the results of ye3rS of
mining, milling, and smelting operations. Mining Companies ran extensive
silver, lead, and zinc mining operations on—site in the late l80 nd ear’y
1900’s. Although several small operations started arto Ceased Ofl the site
after 1930, records indicate that the bulk of the mlnifl9 wastes at iii site
were placed from 1880 to 1915 on the steep slope of the western side of
Snisgg er Mountain near the Smuggler Mine shaft. In the mld.lgco ’ 5 ,
reprocessing facility-was run at tne site, causing the dlsper jo of the
wastes from the relatively distinct piles at thc mine site to other locations
in the vicinity. The reprocessing also spawned a number of Settling Ponds
around thC site. The wastes were dispersed further by subsequent residential
cevel opment.
From the time of the generation of the mining wastes to the present, the
r ater1als have been strewn and dispersed over a wide area and at varying
depths from 1 or 2 feet to 40 feet. The relative toxicity of the remnants or
the waste piles varies with the cagree to which they are mixed with or covered
by other materials (native soil, topsoil, etc.). Since the waste piles have
oeen randomly dispersed, mucn of their disposition is unknown. The site Is
underlain by relatively permeable strati. Ground water and, ultimately,
surface water may be affected by the percolation of precipitation through the
iunerallzec waste materials.
A tiui ber of investigations have taken place at the site. Air quality, stream
sediment, surface- and ground-water quality and soil/tailings data were
coll€cted in the vicinity of the Smuggler site by EPA and the Potentially
aesponsible Parties (PRPs) from June 1962 through June 1986. Analyses of soil
an plant samples taken from the area In 1982 indicated elevated levels of
trace metals (lead, ca 1um) and called the site to the attention of local
State, and Federal authorities. At the request of Pltzin County envirorm ental
officials, the Ea A Field Investigation Team (FiT) performed a sampling
investigation at the site In 1983. The Smuggler site was proposed for the
ational Priorities List (NPL) In October 1984 and becam. final on the PL in
;ay 19C6. On several occasions durIng 1981.1983, news releases, meetings, and
other publicity issued by the Aspen Public alth Department advlsd local
residents against a) the use of garden soils suspected to be derived from
tailings and b) children playing In tailings ( anlop 1986). FollowIng
negotiations with the Identified PRPs In early 1985, EPA approved the PRPS’
proposal to conduct the Remedial Investlgat lon/Feasibillty Study (RI/PS) with
CPA retaining an oversight role.
EPA issued three orders pertaining to the site durIng 1985. In June, EPA
issued a unilateral lnistrative Oreer which names the property owners,
describes the site and potential hazards, and requires that EPA be notified of
and give approval for any movement of the soils or mining wastes in excess of
one cubic yard. An lnlstratlve Order on Consent was negotiated and signed
by EPA and the PRPs in July 1985. This Order accepts the PRPS’ RI/FS work
-------
,H4flS flQ sets ror;n otrier iegaiiy D nc ng agreements to govern various Site
activities. EPA and the pruperty owners a’so entered into a Consent Oroer n
August to undertake a hunted emergency action on the site in which the
heavily contaminated area south of the mine and north of the tennis courts was
Isolated by installing a fence to prevent access, and signs were erected to
warn the residents.
The final RI/FS was submitted to EPA in early 1986. EPA prepared an
endangerment assessement based on tne RI in May 1986, and an addendum to the
RI/PS was prepared.ln June 1986. The data from these and other related
studies are suam arized on Table 1 and FIgure 4.
C. CURRENT SITE STATUS
The total quantity of contaminated materials at the site has been estimated at
approximately 410,000 cubic yards. The site is characterized by high
concentrations of lead, ca 1um, and zinc, as well as elevated concentrations
of arsenic, barium, copper, manganese, silver, and marcuvy as found In
tailings and other mining wastes. Three different amdla were san.pled by the
PRPs and EPA at the site to further define the extent of contamination. The
results of the sampling are:
Soil Sampling . Field activities have concentrated on determining t e
extent of lead contamination. The initial site definition shown on
Figure 5 was adopted as a FIT starting point for investigation when the
site was proposed for the MPL in October 1984. The site definition was
based on data from preliminary soil leao content values compiled by the
FIT investigation. The emphasis of subsequent surface sampling programs
Conducted by the PRPs and EPA was to define the horizontal and vertical
distribution of lead in the soil. A perpendicular grid system with
400ofoot sampling intervals was adopted to provide field reference for
sample locations, and soil sampling went as deep as 35 feet. The
sampling grid Is illustrated In FIgure 6. A s ary of the soil sampling
activities is shown on Taole 2. The Initial FIT site definition was
refined by the PRP efforts which distinguished the site by using four
soil conditions, i.e., mine tailings, fill, man-made fill, and native
soil. Both mine tailings and man-made fill were Considered to be
contaminated with lead at Concentrations of over 1000 pp.. Figure 7
illustrates the PRP site definition. The EPA contractor (Camp, ‘esser &
McKe*) collctad additional soil samples, conducted soil analyses, and
defined the site In terms of the 1,000 ppm soil lead contour with the use
of geostatlstlcs. The resulting contour map (FIgure 8), whIch also shows
contours of higher levels of Contamination, has been adopted as the site
definition sap ‘ EPA and the PRPs.
Surface Water and Sadisant Sampling . FIT conducted surface water
sampling efforts in the vicinity of the S iggler Mine site. The sampling
locations arid the rationale for choosing them are shown on Table 3. A
su ary of the results of the surface witer sampling efforts are shown on
Table 4. Only barium, Iron, manganese and zinc were detected in the
river. In addition, the levels of these constituents found in the river
-------
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-------
• r’\\ •\ % 0• \ ..f__••’ ••;“, ---—._..;— ,..--.
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FIGure 4
CON ISSO
flvcrvleu of Vata Collecllusi Activities
-------
FIp ssrv S
1s,It1 sI Sit. I).i m it lull 11.111
Source: F I I 19114
-------
Table 2
SUMMARY OF SOIL SA PLING ACTIVITIES
1UGGLER SI TE: JULY—AU( UST 1 985
Sampling Procedure jinber of Samples Collected Depth
Surface samplIny 34 soil samples collected 04 Inches
frcm each node of grldpolnt
Test pits 7 test pits 10 feet (average)
15 soIl samples Collected sample co1lecte
at each
lithologic unit
Test boring 1 borehole 35 feet
2 soIl samples Collected Sample collected
for each unit
Source: Fred C. P rt
1985
-------
S
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FIguie 6
GRID SYSTEM SHOWING SURFACE
SAMPI.IIIG I.OCA1IOPI ;
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-------
FIgure 7
MAP OF SURFACE SOIL CONDITIONS
AT THE SMUGGLER MOUNTAIN SITE
Messeds Fill
Miss TeSNage
Msaa•d• Fill I MIa• ,•*. s
o $.olscs Ra.pN. (•t.ll...
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FIR •ITANIS SON CONIIUON$ 1 lEVIS TI Pt*US OS. VOINNI NI
IDOlS NOt 1 5 50W lOSS SINI,$ flPIC*t$.V 5 1550( 5 5000 p . 5*550( 1
-------
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Figure $
Curr.nt Site Delinit Ion IL
L(AD CONTANINAT ION
Pb KRIGCD CSTIHAT(5
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-------
Table 3
iWATJG RU ATRN I RR IUMI VAUR auwtitii sr n
SWi ii
f I *ihii t tia MtIapJe
- - with i with Poag-1s ,t ‘a]tte aiIer Q atfty revIan to
IntIu of srIs
9I-4IO .k II eIa, amth c* with ftmtN Ia*t. dr *k t& qiallty of t 1nth i
of Q t I I Ibsitsin site.
9 .Øfl rb k 1I r wiflix* with I mter sItat. *rbi sk aLIty idor to
lnfli of Itmt O a I at tor lnth of
Ior I*uitala sit..
V nw1 ikib prior to w flswnce with t sJi te Oa 1 i 1 ne.I &*Intie prior to
staa èali . dtadwie Mt. st tor uU.cikm syst.
Ibili. GI stt èab prior to cmflsioe isbte lUll. CIvsm éab prior to Intbic*
with 1r rk Il . of rbr k ftIv .
k II - • cmnflumes of UI. LMte sir qiality of arIr Poik liver prior
• GI deft èaIi to its IntIaii* of a ’ .lnli or ai11Ig
jk.itsu In. Ior lbmtaln sit..
Oil I .
-------
Table 4
Concentrations o( Dibsolved Heta1
in Surliice Water Samples
StatI
Di 1vu 1 l ta)3
I
-
1s
Ai dc
Zinc
l iuay
(i /1)
dia
lb
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V
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10
10
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.
N)
N)
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N)
78
91 0 ( rb a* e
1flm.c*v1th .$u,Q, )
it
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N)
N)
1 1
193
91-01W. ( à i øind tp)
2.7’
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II)
278
K)
39
41
30
727
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10
P0
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377
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41
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1800
ft,
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N)
N)
10
P0
P0
29
130
321
-------
were within the Compliance range for ambient water quality standards set
by tne State and EPA. Stream sediment sar. ples were also collected ifi the
vicinity of the site, the results of which are suer.arjzed on Table 5.
3ased on available data and in Consideration of the reducing Conditions
of tailings piles, it was Concluded that on—site contaminants were not
mobile enough to lead to a Substantial Increase in the levels of metals
in surface water and surface water sedir ents.
Ciround WaterSamp1fng . Seven existing private wells were sampled and
ei ht monitoring wells were installed to obtair ground water data.
Private wells PW-5 and PW —7 are considered to be down—gradient. EPA
installed four monitoring wells, two of which were dry. EPA subsequently
installed four more monitoring wells. EPA well GW.0l was established as
an upgradlent well. .PA well —Q5 was established as downgraølent, and
EPA wells GWO7, GW-08, GUO9, and GW-l0 wire established as on-site
wells. All ground water well locations (private and EPA) are shown on
Figure 9. The private wells were sampled by the EPA FIT In 1983, results
from those tests are shown on Table . Ground-water samples were
collected from the six operational EPA monitoring wells in November 1985,
an.,1 February and May 1986. Results frogs thi dissolved-metals analyses of
these samples are presented on Tables 7, 8, and 9. Water-quality trends
from these sampling data indicate that lead and arsenic are not prtsent
as ground water contaminants. Nowever, elevated levels of ca ium were
noted at two private well sampling locatloi ,s (Table 6) and at two EPA
monitoring well locations (Table 9).
Of particular Importance to the selection of vie recomended recied was
the absence of lead in the well sam,les and the variable occurence of
cac ium in G —O7 near the Maximum Contamin r 1 t Level (MCI. .) of .01 m/1 as
established by EPA. In addition, levels of uranium and gross alpha were
found to be elevated In G J.U7 and GW-09. Zinc concentrations were also
found to be highest In PW—7. The PRPS have postulated that despite the
abundance of calcium carbonate In the host rock, localized pockets of
mineralized materials could produce leaching conditions if derived from
the core of the mineralized zone. Using the results from the Focused
Feasibility Study and ground water monitoring, EPA has deter Ined that
the potential ground water problem (as Indicated by elevatso levels of
cadmium, zinc, uranium, and gross alpha in GW-07 and GW-09) would most
likely be adequately addressed by the prevention of Infiltration of
surface water through the tailings. Continued long—tare monitoring of
the ground water was d d necessary to evaluate the effects of tile
remedy on the ground water quality.
Air Samplinq . EPA took 115 samples of air particul,ee matter from a
background site and four on-site locations in 1985. A compilation of the
resulting data Is presented on Table 9. Analyses of these data reve , Ieø
that levels of arsenic, cadmium, lead and zinc In the air on-site were
elevated as compared to background. however, only cadmium and arsenic
were found to be present at levels above the proposed National
Enviror .ntal Standards for ) zardous Air Pollutants- (ML 4APS).
-------
t&
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-------
V
Table 7
GROUND WATER ANALYSES FOR NOVEM8ER 1985
Parameter
well
No.
GW .1
GW-5
Gw”7
GW .8
GW .9
GW-1O
Arsenic
ND
-Cadmi n
MO
ND
ND
ND
ND
ND
Calcium
0.004
0.007
ND
ND
ND
Iron
Lead
4.59
ND
ND
136 .
ND
143
NO
20
ND
119
ND
128
ND
Magn.si
14.1
ND
ND
ND
ND
ND
Manganese
0.017
23.8
52.5
5.74
38.5
36.8
Potassium
ND
ND
0.052
ND
NO
0.343
SodIum
ND
1.92
NO
ND
ND
Zinc
0.062
9.69
0.060
6.68
1.00
• 4.16
0.018
ND
0.413
6.35
0.053
Notes :
Concentrations In m /L; metals are di sSolye4.
Validation criteria qualifiers pertain to some data; details are lnclude4
In REM II files.
Soitrce: COM 1986.
-------
Table 8
oouwa w*iti ao*tvsts ro. rtuu*av 906
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0.440
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Source: tIN INS.
-------
TABLE 9
GROUND WATER ANALYSES FOR METALS
MAY, 1986 SAMPLING
eter Ground Water Wells
01 05 07 08 0 9 09
nurn [ 40.] [ 17.] [ 36.] [ 29.] [ 18.] 1l.u [ 2 )
ny 25.u 25.u 25.u 25.u 27. 25.u
10.u 10.u 10.u 10.u 1O.u 10.u LU.u
[ 62.] [ 81.) [ 33.] [ 40.) [ 28.] [ 30.] [ 62.]
hum 1.Ou LOu 1.Ou 1.Ou 1.Ou 1.Ou
4,Qu 4.Ou 18.* 4. Ou 54 4 .Ou
47000. 124000. 29500. 192000. 138000. 137000. 131030.
lurn 4 .Ou 4,Ou 4.Ou 4 . Ou 4 .Ou 4.Ou
3. Ou 3.Ou 3.Ou 3.Ou 3.Ou 3 .Ou
- [ 11] 3.Ou [ 5.5) 3.Ou [ 5.2] 3.Ou 3. lu
[ 17) [ 7.7] [ 72.] [ 25.] [ 9.8) [ 5.8] [ 3.2]
5.Ou 5.Ou 2 5.u” 5.Ou 5.Ou S.Ou
- 146003 21800. 99800. 5540. 49200. 462000. 35è0 0 rj.
ese [ 14.] [ 4.6] 23 [ 6.1] [ 3.5] [ 4.7] 16
O.Zu - 0.2u 0.2u O.2u 0.2u 0.2u
8.Ou 8.Ou 8.Ou 8.Ou .0u 8 .Ou
[ 1030.] [ 1730.] [ 2190.] [ 602.] [ 1760.] [ 148u.] [ 12 O.j
7.9 7.9 25.u 5. Ou 5.Ou 2. Su
• 3.Ou 3.0 3.Ou 3.Ou 3.Ou 3 .Ou
1 20600. 7920. 6210. 2250.] 5080. [ 4730.) S43..
urn 10. 10.u 10.u 10.u 10.u 1O.u 13 u
17.u 17.u 170.u” 17.u 170.u 170.u
urn 2.0 2. Ou 2. Ou 2.Ou 2.Uu 2.Ou 2 . u
87. 48. 2510. 25. 590. 596. 3 .
esult is value greater than or equal to tfte Instrument detection limit but less tnan t e
ontract required detection limit.
lement was analyzed for but not detected. Detection Halt Is reported.
xceeds Maximum Cont me*t Level (Primary Drinking Water Standards)
st inated due to spltt’recover l.s outside limits.
lution Factor of 5
I) values are expressed in micrograms per liter (ugh)
Source: cON 1986
-------
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-------
Cperaole Jnit 1: Site Remedy
0pev able unit 1 is separated into five components as follow:
A. Source Isolation of High Leve Wastes . Isolate soils and tailings
with levels of lead at or above 5,000 pp b,’ excavation and removal to a
secure repository. This alternative could involve either the removal of
Such material by shipping It to a RCRA certified facility, or by
depositing It in a secure repository on—site, as defined by EPA. EPA has
identified -a suitable repository on the site, the County-owned Mollie
aibSOn Park. If the repository is chosen for deposition of the
high-level wastes, it will be excavated to the extent necessary to
accomodate the entire volume of high level waste on the site. It will
then be prepared to Specifications set bj EPA that adequately address tn
issues of surface runn and stability. All hlgh.leve l wastes from the
site (other than the mine site, itself) will be consolidated and placec
In the repository. The repository will be graded and capped in
accordance with the appropriate and relevant RA standirds for landfills
(caQped with a multi—layer cap possessing a permeability of at least
lCr’j, A drainage system will be designed according to EPA
specifications (designed to pass the 100-year runoff event with a minimum
of erosion). The repository will be under the perpetual care of a
permanent entity, PltkIn County, to assure the permanent d15p $itj and
zero mobility of the contaminants.
. Source Isolation of Low Level Wastes . Confine soils with levels of
lead bclow l,(J00 ppm in such a manner that direct contact, surface water
erosion, and wind dispersal are precluded. This operable unit involves
the Identification of the affected areas using the geostatistica
iso 1eth nap. After Identification and possible further sampling to more
clearly define the contaminated areas, the low level areas will either be
covered by six inches of topsoil, graoed, and revegetated, or covered
wth six inches clean fill plus sIx Inches of topsoil and graded. Areas
neeaing further Identification will be defined by additional sampling.
If such sampling Is performed by the PRPs, EPA will verify such
sampling. Areas alrea4y rlmedla.ted by property owners will be examined
by EPA to determine c plianc. with design Standards.
C. Increased Ground Water Monitoring . Because the ground water system
In the area of the sit. is so uncertain , groundwater monitoring Is
necessary to confirm the effectiveness of the remedy. ?dditlonil well $
will be Installed as deemed necessary by EPA. A monitoring grid and
monitoring schedule w1 be *staDllstie4. iarter1y reports to EPA will
describe the results of monitoring and any trends observed. Ground water
in the vicinity of the site will be monitored fora period of five (5)
years quarterly to determine efficacy of the capping In enhancing ground
water quality. After tne close of the mon1torlng period, the decision
must be made by EPA to either Implement plume capture and treatment,
select alternate concentration limits, or take no further response action.
-------
i. Alternate water 3u p1y . This operable unit invo’veS the
identification of Gomestic water wells i ied1ately downgradient of the
site. After identification, such wells wifl be replaced by hook-ups to
the City water supply nd will no longer serve as domestic-use wells.
£. Operation and Maintenance of Low and High Level Waste Caps . The
purpose of cap inspections is to note and repair any deterioration,
disturbance, or discontinuity before ft can impact cap integrity. heel1y
inspections are anticipated during the first year. 81-monthly
inspections wifl take place for the second year. After two years,
inspections will be conducted monthly, and from the beginning of the
fourth year, quarterly inspections will be conducted for the fcflowing
twenty-sIx years.
Operable Unit 2: MIne Reclamation and Ground Water Corrective Action
A. Mine Reclamation . The Smuggler. 4 rant Mine site will be remediated
separately from the remainder of the site. The current extant of
toxicity and mobility of the contamination at the mine site is unknown.
An addendL to the existing Remedial Investigation and Feasibility study
will be prepared to characterize the wastes and determine the appropriate
extent of remedy at the Smuggler- .srarit Mine site in accordance with the
liational Contingency Plan and i i accordance with the applicable or
relevant and appropriate requlremcnts necessary to rn et Federal public ‘
hc•alth and environmental requirements. The Smuggler Mine RI/F5 will be
subject to public coninent and a reconmiended remedy Will be presented.
The appropriate extent of remedy, ccnsistent with tne ICP, would address
the possible historic value of the mine site. The plan for mine site
rei eoiation, consistent with the goals and objectives of the RI/FS and
I CP , will be prepared bj the owners of the mine site and submitted to EP
for approval, or would be prepared by EP/. In accordance witn the
requirements of the National Environmental Policy ict (kEP ), if the mine
site is declarec a National Historic Site, the buildings and other
structures on the mine site uld be adequately maintainea for their
historic value. Applicable and relevant or appropriate standards and
requirements for the safety of warkers and visitors to the mine sit.
would be complied with. At the same time, wastes on the mine site will
be treated or remed lsd so as to prevent and/or mitigate the present or
future threat of release In a manner that Is protective of public health,
welfare and U i. envirwaent. Such remedy wauld provide a level of
protaction of public health and environeent comparable to the remedy on
the remainder of the site.
B. Ground Water Corrective Acti on . If the results of ground water
monitoring conducted during the first operable unit Indicate that
corrective action is necessary, alternatives will be developed tO address
the situation and possible response actions will be considered.
C. Perfo,,nan:e of Mine Reclamation a’id Ground Water Corrective Action as
Approved by
A conservative estimate of the total capital and operat1 and maintenance
costs for the rec ’ended remedial alternative Is 1.5 to 2 millIon dollars.
A
-------
Smuggler Mountain Mining Waste NPL Site Summary Report
Reference 2
Excerpts From Remedial Investigation/Feasibility Study,
Smuggler Mountain Site; Fred C. Hart Associates, Inc.;
March 1986
-------
3F FILE NUMBER
AD lfST *T1VE RECORD
REMEDIAL INVESTI ATI 1/F!ASI3ILITY STUDY
4UGGLER MOUNTAIN SITE
Aspen, Pitkfn County, C. 1orado
March 1986
Prepared by:
Fred C. Hart Associates, Inc.
530 F fth Avenue
1ew Yort, New Yort 10036
-------
1 —1
1 .0 EXECUTIvE SUP ARY
The Sn igg1er Mountain site is located In an old silver and lead mine
area which Is located ininediately northeast of the City of Aspen, Colo-
rado. Mine tailings produced during the peak mining years, between 1879
and 1920, were piled outside of the mine shafts in the vicinity. Over the
course of the years, the tailings have been moved, used for fill material,
or have been mixed with man-made materials. At the present time, the site
is almost completely covered with residential developments and recreation-
al facilities. Some construction Is still underway at the Centennial
Development. On a portion of the site owned by Pitkin County, a public
park is planned.
A number of investigations have been undertaken at this site. Ecology
and Environment, Inc. (‘E&E) Field Investigation Team performed a sam—
pling investigation at the site in 1983. The Investigation was the result
of a request by Pitkln County to characterize any human or environmental
threat posed by abandoned mine tailings In the northeast quadrant of
Aspen, Colorado. The county became concerned following the analyses of
soil and plant samples taken from the Aspen area which indicated elevated
levels of trace metals, specifically lead and cadmium (Boon, 1982). An
initial report of the results of the E&E sampling was drafted in response
to a Technical Directive from the Environmental Protection Agency ( EPA M )
and was distributed in March 1984 (E&E. l984a). E&E was subsequently
directed to perform a limited groundwater investigation at the site fol-
lowing a proposed ranking on the National Priority List of Hazardous Waste
Sites. The results of this groundwater investigaton were inconclusive as
to the presence of groundwater contaminants originating from mine wastes
on the site, but did not eliminate concern over possible groundwater
contami nation.
Recently, Engineering-Science performed a study sponsored by Western
Slope Development Company, and a plan for surface covering and revege-
tation was developed for certain areas surrounding the Hunter Creek
condominium development (Engineerl ng-Science, 1985). SimIlarly, studies
sponsored by Centennial—Aspen, a Limited Partnership, analyzed the distri-
butlorms of contaminants on the Centennial development site and recomeuended
(0023F)
-------
1—2
topsoil coverl-ng and landscaping to Isolate contaiflated materials (B n
1983).
In July1985. discussions between the EPA and a number of potentially
responsible parties* associated with the site Culminated in the signing of
a Consent Order under which these parties agreed to perform certain stu-
dies for the EPA. There Is not agreement as to whether groundwater is
affected by contaminants at the site. Nonetheless, for purposes of
reviewing remedial technologies, groundwater Impacts were assumed. Conse-
quently, an initial focused feasibility study of remedial options for
groundwater protection was performed, followed by this remedial site
investigation and final feasibility study (R 1/FS). Fred C. Hart Asso-
ciates was retained by the group of apotentlally responsible partiesa to
carry out these studies.
The focused feasibility study for groundwater remedlation (HART.
1985), which preceded the RI/FS, examined a range of possible remedial
alternatives for the site. This study concluded that many remedial alter-
natives aimed at groundwater protection were not technically feasible for
a number of reasons, Including technological Infeasibility, unreliability,
and significant environmental impact. Several remedial alternatives were
found to warrant further investigation, including surface grading and
revegetation, removal of contaminated materials from the site, and extrac-
tion and trea ent of groundwater leaving the site.
The Initial screening of remedial alternatives performed by the
focused feasibility study allowed a more cost-effective remedial investi-
gation study plan to be devised. This report contains the results of the
RI/FS program.
A. Surface Contamination
Because of the highly modified nature of the site, a result of years
of residential construction activity, the remedial investigation was
- (0023F)
-------
1-3
designed to carefully examine the lead Concentrations In the soils and
present surface distribution of different soil types containing tailings
Which could be related to the lead contamination.
The application of geoStatistics to vastly different sample popula-
tions can be misleading, particularly In instances where materials have
been relocated. Mine tailings possessing high levels of lead have been
relocated, seemingly at random, over the surface of the site. Tailings
and fill materials with relatively high lead concentrations and used in
small, distinct areas such as driveways or lawns would probably not be
identified by geostatistics. Conversely, It might be assumed that an area
between several widely spaced points which reported high lead levels would
also contain high concentrations of lead; the reality, though, might be
that the area contains native soil with only background concentrations of
lead. Sampling programs could be devised through geostatistical tech-
ntques, such as analysis of variance, to examine for such variations.
Such analyses would suggest an appropriate sampling interval.
The EPA decided that, for purposes of action under CERCLA, the site
was to be defined as Including those areas with surface contaminations of
over 1,000 ppm of lead. In order to assess contaminant concentrations and
distributions at the site, extensive surface and subsurface soil sampling
and testing was performed. Aerial photography and ground surveys of the
site established an accurate soil classification system upon which soil
mapping could proceed. The soil mapping methodolo was confirmed by
chemical analysis of the soil samples, which indicated that all tailings
materials or materials which contained mine tailings had lead levels In
excess of the EPA ’s action level of 1,000 ppm, while soil types which did
not contain tailings were found to contain less than 1,000 ppm in every
case. This relationship was demonstrated statistically to a 99% conf 1-
dence level. A series of detailed maps describing the distribution of
these soils is contained in the report.
(002 3F)
-------
1-4
B. Groundwater Protection
In the initial conversations with the sponsors of the RI/FS, EPA
expressed concern over the potential of the tailings material to generate
leachate, a possible source of groundwater contamination on and off the
site. Acid/base analyses in the RI/FS were designed to address these
concerns. The acid/base balance studies demonstrated that acid mine
drainage problems probably could not exist at the site, given the buffer-
ing capacity of the natural soils.
Water balance studies, analyzing drainage characteristics of the site,
showed low permeabilities and percolation rates over most of the area
which would prevent most leachate generation, although a small potential
was found for generation of leachates containing lead. (This potential
may be present in the Molly Gibson and Cowenhoven Tunnel mine drainage
ditches which could be losing water over areas which contain mine tail-
ings, possibly recharging groundwater with potentially contaminated leach-
ates.)
C. Analysis of Remedial Technologies
Environmental protection goals and remedial objectives used to analyze
potential remedial alternatives called for an isolation of the source of
contamination (lead In mine wastes) to prevent direct contact and the
distribution of windblown dusts, along with the protection of potential
groundwater receptors.
Potential remedial technologies screened prior to use in the develop-
ment of alternatives Included capping, grading, revegetation, surface
water diversion, alternate water supply, groundwater collection and treat-
ment and complete excavation, removal and disposal of contaminated materi-
als. All of these technologies were evaluated and retained for use in
developing remedial action alternatives for the uggler Site. Three
technologies —— incineration, groundwater barriers and flood control --
were evaluated and considered to be not appropriate for use at the site.
- (0023F)
-------
2—1
2.0 BACKGROUND !NF0 4A pj
This chapter of the Remedial Investigation at the Smuggler Mountain
Site presents a brief overview of background irifor nation. Section 2.1
discusses site background Information Including the location of the site,
waste disposal practices at the site, and site geology and hydrology.
SectIon 2.2 briefly discusses previous Investigations of the nature and
extent of contamination problems at the site. Section 2.3 discusses
previous response actions at the site.
2.1 Site Description
2.1 .1 Loc t1on . The site is located limnediately northwest of the
City of Aspen In Pltkin County. The tailings area Is situated In the
northwesterly trending valley of the Roaring Fork River at the base of
Smuggley Mountain. A location map Is presented In Figure 2—1.
2.1.2 Waste Disposal Practices . The area encompasses approximately
75 acres of developed and undeveloped properties. Tailings from the
Smuggler, MotIle Gibson, Free Silver and perhaps other mines, the
Cowenhoven Tunnel and from past smelting and milling operations related to
these mines and tunnels have been deposited tn the area. In some places,
tailings have been mixed with native soil. Native soil also comprises
part of the surface of the area, with fill material derived from native
soil which does not contain tailings.
The deposited tailing material was a result of the mining and mi11iri
of silver, lead and zinc. The distribution of the tailings, as well as
their reworking since their original distribution, was not well—defined.
Past records Indicate that tailings on the Smuggler Mountain site were
placed there from 1880 to 1915. The tailings piles from the Cowenhoven
Tunnel were leveled and scattered when the Hunter Creek condominiums were
built. Recent investigations indicated that some of the tailing piles
were leveled and tailings were scattered over the present sites of the
Smuggler Trailer Court, Smuggler Racquet Club, Hunter Creek Condominiums
and the Centennial-Aspen Condominiums. e objective of this Remedial
(0647F)
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Investigation was to define the extent of tailings and fill related soil
types for potential remedial actions.
2.1.3 Topography . Topographically, the overall site slopes moderate-
ly toward the west and southwest, with an overall gradient on the order of
approximately 10 to 15 percent. However, at Isolated locations throughout
the site and along the southeastern boundary, gradients on the order of
100% occur. The ground surface elevation ranges from approxImately 7930
to 8160 feet above mean sea level.
Throughout the years, parts of the land surface at the site have been
altered as a result of mining and earth-moving activities. Characteris-
tics of the site Include some small closed depressions. Several of these
areas of interior drainage are located above abandoned mine shafts and
tunnels. Some of these closed depressions are the result of ground
subsidence, particularly over the old Mollie Gibson Mine shaft, the Free
Silver Mine shaft and Cowenhoven Tunnel. A depression approximately 12 to
15 feet deep is evident at the Free Silver shaft. As mentioned, the
topography on the site has changed due to miscellaneous grading (both
cutting and filling) through the years. It appears that portions of the
site have been either borrowed from, filled on, or disturbed by grading.
2.1.4 Hydrology . The Roaring Fork River passes the site at a dis-
tance of approximately 1000 feet to the southeest. In this reach, the
river elevation is about 7870 to 7920 feet above mean sea level. There
are no major natural drainage channels crossing the site. However, site
drainage Is affected by two small to moderate—sized basins located to the
east and northeast. Hunter Creek passes approximately 500 feet north of
the site. The Salvation Ditch, an irrigation canal, surfaces on the
northern part of the site from a buried 45 inch concrete pipe, and trav-
erses the site at an elevation of approxImately 8000 feet.
Any drainage from the site occurs largely as runoff although channeli-
zatlon Is apparent from mine discharge water. Specifically, drainages
from the Mollie Gibson Mine shaft and Cowenhoven Mine access tunnel trav-
erse the site. Each discharge Is In the range of 1 cubIc foot per second
(0047F)
-------
2-4
(cfs) or less. Existing water quality data from each channel show the
discharge to be moderately laden with dissolved constituents, Including
Iron, manganese and zinc. Based on samples collected in 1983, total
dissolved säilds (TDS) concentrations range from 540 mg/i for the Mollie
Gibson discharge to 918 mg/i for the Cowenhoven Tunnel. The Mollie Gibson
and Cowenhoven drainages discharge to the Roaring Fork River and Hunter
Creek, respectively. Discharge in both streams is seasonally variable.
For the Roaring Fork River, low flows of 15—20 cfs occur during the Jan-
uary through early March perIod, and high flows of typically 400 to 800
cfs occur durftig the mid-Nay through early July period. As for Hunter
Creek, flows generally range from 5 to over 400 cfs during similar periods
(CON, 1985).
2.1.5 Kydrogeology . Generally, the groundwater system underlying
Snuggler Mountain is dominated by extensive honeycombed mine workings.
These workings serve as conduits transporting groundwater from within the
mountain to the level of the Roaring Fork River. Groundwater in mountains
such as those surrounding the Roaring Fork River Valley discharges into
the center of the valley towards the river valley deposits (Freeze and
Cherry, 1979; Todd, 1983). Flow in the valley deposits would be down
valley, in the direction that the Roaring Fork River flows.
The investigation performed by Ecology and Environment, Inc. in March
1984 indicated there was no alluvial groundwater system underneath the
tailings at the site. Recent groundwater Investigations by Camp, Dresser
and Mckee, however, Indicated that water—bearing medium grain sand was
present underneath tailings in 3 of 4 monItoring wells (Appendix G). The
hydrogeology of the uugg1er Site is complex for several reasons. First,
because of the position of the site on a valley wall, it is difficult to
determine the d l scharge of groundwater from the bedrock aqul fer into the
alluvial aquifer at that point. Secondly, since the area had been exten-
sively mineralized and mined, the generation of heavy metal contamination
in groundwater from the bedrock aquifer would be expected. It Is Impor-
tant to note that ft Is not possible to install a well in alluvium to
monitor upgradient background water quality conditions. For these
(0047F)
-------
2-5
reasons It Is extremely difficult to determine the groundwater flow and
chemical background conditiOnS at the site and the potential Impacts of
the site on the groundwater. The recent well drilling effort by CDN did
not aid In identifying groundwater flow directions at the site.
The site is underlain by various surficial deposits which Include
alluvial deposits, glacial moraine and glacial outwash deposits. These
deposits are characteristic of valley fill deposits. It is estimated that
the valley fill deposits are several hundred feet thick In the Roaring
Fork River Valley (Lincoln DeVore. 1983). DependIng on their extent and
thickness, as well as permeability, these deposits could yield anywhere
from 5 to 1,000 gallons of water per minute.
Underlying the aforementioned surficlal deposits, the bedrock aquifer
is comprised of the Gothic Shale, Belden Shale and Leadville Limestone ‘
Formations. The occurrence of water is a characteristic of fractures and
solution conduits found In the aquifer. The Leadville Limestone, which
may be up to 200 feet In thickness, has been reported to yield as much as
several thousand gallons of water per minute.
2.2 Previous Investigations
Various studies have been conducted in the recent past to characterize
the tailings around the S uggler area (Boon 1982; Lincoln DeVore, 1983;
Boon 1983; E&E 1984*; Clement 1985; McIntosh 1985; EngIneering—Science,
1985). Resul ts of these studies show that several metal s were detected I n
the soils and tailings. Concentrations of arsenic, barl an, cadmium,
copper, lead, manganese, mercury and zinc In the mine tailings and soil
were considered elevated compared to a selected soil background sample
(E&E 1984*). The concentrations of these metals In the samples also
exceeded the expected concentration of those elements found In similar
native soils throughout the United States. These soil and tailing areas
and their constituents noted to date are described briefly below.
(0047F)
-------
2-6
2.2.1 Tai11ng . Six tailing samples were colleCted in Septan er 1983
(EU 1984a). EU reported that chemical analysis of these samples Show
elevated concentrations of arsenic, barium, cadmium, copper, lead, manga..
nese, mercuv’y and zinc. Arsenic, cadmium, copper, mercury, lead and zinc
were reported, by EU as being above background levels expected for these
types of soils IS generally described in the literature by Connor and
Shackletter (1975).
2.2.2 Soils . Preliminary soil samples were collected dOwfl5l p from
the tailings piles during September 1983, at an area underlain by graded
tailings and covered with transported topsoil (EU l984a). Chemical
analysis of these samples indicated that, on the average, at some di5ta
downslope of the tailings soil showed elevated levels of arsenic, barium,
cadmium, Copper, lead, manganese and zinc.
Results from other sampling events conducted by Boon (1983) and the
Aspen/Pittin Enviro,m ntal Health Depar nt have shown some elevated
metal concentrations when compared to Connor and Shacklette,. (1975). It
should be noted, however, that Connor and Shackletter (1975) did not refer
to background in areas near mines which may have naturally occurring
elevated levels of lead. Boon’s data showed elevated levels of cadmium,
copper, lead and zinc. Three samples were collected at the Smuggler
Trailer Part by the Aspen/Pit in Environmental Health Depar nent and
analyzed for lead and cadmium (CDI I 1982). The average and maximum concen-
trations reported were 90 and 223 ug/g for cadmium and 11,723 and 21,700
ug/g for lead. Whether these samples were of soil or tailings is unclear
(Clement 1985); however, subsequent work by Camp, Dresser and Mckee, Inc.,
suggests they were either man-made tiii material or tailings (1985 written
co4mlun icat lon).
In June 1985, Eng1neering_Scien (1985) tested eleven surface samples
and three subsurface samples In the Hunter Creek area for concentrations
of heavy metals and the EP toxicity of those metals. This Is included as
Appendix A. Although these soils are not able to generate acid conditions
(0047F)
-------
2-7
similar to those In the EP loxicity analyses, Englneering. jen conclud-
ed that the levels of ca 1tm,, zinc and lead were found to be elevated in
SOnIe soils on the Hunter Creek property.
2.2.3 ToxIcity of Contaminants . The site contains elevated concen-
trations of heavy metals in tailings and contaminated Soils. Concentra-
tions for these metals could exceed levels at which toxic effects have
been observed tn plants, wildlife, domestic animals and man. EPA has
performed a risk assessment and has set action levels for soil cleanup at
1,000 ug/g lead.
Lead and ca nium are the two metals of most concern at the site
because of their concentrations and acute toxicitles. Lead concentrations
in some types of soils in the area could exceed the 1,000 ug/g action
level set by EPA. Lead exposure related toxicity has been reported for
children. Children of the 1—5 age group are at greatest risk because of
their soil ingestion habits and greater Susceptiblity to blood lead pot-
soni ng.
It Is important to note that the blood lead studies conducted to
establish the 1,000 ug/g soil lead concentration were based on atmospheri-
cally deposited lead from automobile emissions and smelters. While toxic
effects of lead ingestion in children from lead based paints has been
doclinented, it has not been shown that exposure to lead in tailings and
soil such as that at the uggler site will produce elevated blood levels
(CDI’I, 1985).
Various forms of ca 1im, are acutely toxic, and ca iian compounds are
generally more bloavailable than lead compounds. A groundwater sample of
13 ugh ca iua exceeded the ambient water quality standard of 10 ug/l, In
one well on one occasion. This well was checked again and found to be
less than 10 ugh.
Due to the relatively neutral pH (6.38-7.22) of the tailings, soil and
bedrock materials, the metals on the site are in relatively insoluble
(0047F)
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2-8
fonns. The Insolubility of the metals decreases their bloavailability
and, therefore, toxicity. None of the metals are volatile, and, thus,
they are expected to persist for an extended period of time (CDM, 1985).
2.3 Previous Response Actions
A number of Investigations have been undertaken at the site. Pitkin
County became concerned following analyses of soil and plant samples taken
from the area. Analyses indicated elevated levels of trace metals, speci-
fically lead and cadmium (Boon, 1982). The Ecology and Environment, Inc.
(E&E) Field Investigation Team performed a sampling investigation at the
site In 1983. The investigation was conducted resulting from a request by
the county to characterize any human and environmental threats posed by
abandoned mine tailings in the northeast quadrant of Aspen, Colorado. An
initial report of the results of the E&E sampling was drafted in response
to a Technical Directive fran the Environmental Protection Agency (EPA)
and distributed in March 1984 (EIE, 1984a).
EPA requested Camp, Dresser & McKee, Inc. (CDM), to prepare a Draft
Work Plan for the Remedial InvestIgatIon/Feasibility Study (RI/FS) of the
site. A group of potentially responsible parties retained Fred C. Hart
Associates, Inc. (HART) to provide technical support. Because gaps exist-
ed in the database used for the ranking, EPA, through its subcontractor
Ecology and Environment (E&E), performed a hydrogeologic assessment at the
site to address the appropriateness of the ranking of the site. The
assessment s inconclusive. EPA, in a Consent Order and Agreement with
the group, has worked with Fred C. Hart Associates to develop and carry
out a Remedial Investigation at the Site. This report contains the
results of that Investigation.
( 0047F)
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3—1
3.0 SU* ARY OF FIELD INVESTIGATION ACTIVITIES
A group of potentially responsible parties retained HART to perform a
remedial lnyestlgation at the Smugglers Mountain Site. The scope of work
contained In the remedial investigation was agreed to between EPA and the
group of potentially responsible parties prior to the Initiation of any
work activities at the site. This agreement took the form of a consent
order. To insure that the scope of work was adequate, EPA required the
submission of a Focused Feasibility Study (FFS). The FF5 examined the
various options for the reinediation of groundwater at the site. The FFS
found that subsurface technologies for groundwater remediation at the site
were not feasible for technical reasons. The results of the FSS enabled a
more cost-effective remedial investigation and feasibility study to be
undertaken. The Investigation was conducted In July-August of 1985. The
sampling program consisted of three phases: surface mapping and sampling; ‘
subsurface sampling activities, and surface water studies. Table 3-1
sunriarizes the sampling program.
Because of the suspected lead contamination, the emphasis of the
surface sampling programs was to define the horizontal distribution of
lead in the soil. Samples were obtained using three different techniques.
During the sampling program, 34 samples were collected at the surface
using a clean plated steel trowel. In addition, soil samples were
obtained from 7 test pits dug with a backhoe. Finally, soil samples were
obtained using a solid stem auger and split spoon sampler.
3.1 Surface Sampling
The surface field activities were designed to determine the lateral
extent of the mine tailings and other soil types at the Smuggler site and
to define the lateral extent of heavy metal contamination and its associa-
tion to soil type. This work involved the development of a reference
grid, soil sampling and soil mapping.
3.1.1 Procedures . A grid system was needed to provide a field refer-
ence for sample locations (Figure 3-1). This was established through the
(004SF)
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3—2
TABLE 3-1
SUMMARY OF SC L SA;• PLING Ac’r vI :Es
SMUGGLER $1E. JULY - ‘JGU5T 1985
Sampling Procedure Number of Samples Collected Depth
Surface sampling 34 soil samples collected 0-6 inches
from each nods of gr dpotnt
Test pits 7 test pits 10 feet (ave’age)
15 soil samples collected sample collectec at
each lithologic un’:
Test boring 1 borehole 35 feet
2 soil samples collected Sample collected
each litnologic r:
I
-- -
-------
c’
•sou.ii -s
scas, I I1’s
o ann ,o soo
S
GRID SV3TEM ShOWING SURFACE
SAMPLING LOCATION ;
I ;)
SJJ
-------
3-4
use of aerial photographs and the Centennial site construction map. Two
baselines were developed from the existing Centennial Project Grid and
perpendicular lines marked at 400’ intervals. Each grid point was marked
using survey tape and the correct coordinants. The grid covered the
entire acreage owned by the named PRPs, plus the 1 IT*diate surrounding
areas.
Significant landscape points noted on both aerial photographs and
established reference objects on the site and In surrounding areas were
correlated to develop the baselines. The accuracy of the established
baselines was assessed by using the standard land surveying technique of
measuring tape and compass. The sampling program took place July 22
through August 1, 1 985.
Soil samples were collected and tested for heavy metals In order to
determine the lateral extent of the affected areas. The samples were
collected from each node on the grid, producing a total of 34 samples.
Samples were collected from the surface to a depth of six inches using a
plated steel trowel. The samples were placed directly into sample jars
and analyzed on—site.
In order to avoid cross—contamination between sampling, strict decon-
tamination procedures were followed. All trowels were decontaminated
using a detergent and water wash, tap water rinse and distilled water
rinse.
- i—s1te analyses were provided by EPA subcontractors, Camp Dresser
Mckee. This Involved the utilization of a Columbia Scientific X-Met 840
portable x-ray analyzer. Lead values were determined for all 34 grid
point samples. In addition, 15% (sIx) of the surface samples collected
had duplicates sent to Rocky Mountain Analytical Laboratories ( AL) of
Arvada, Colorado, for verification of the technique. Appendix A presents
the analyses performed by AL, Including ial1ty Control Data. The
samples were analyzed at 4AL an EPA contract laboratoTy for metals,
according to EPA approved analytical techniques. Sample analysis were
deemed to have an acceptable level of ial1ty Control. As requested by
- (004SF)
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3—5
EPA, the samples were tested for arsenic, barium, cadmium, copper, zinc,
manganese, iron, lead and mercury. See Table 4-1 for a comparison of the
data.
Concurrently with the sampling, the litholo , of the soil sample was
described. The soils were classified in a two—fold process. The initial
determination as to the soil type was made at the sample location. The
sample was described by its color, grain size arid the presence of man-made
artifacts. The general setting of the sample, including the distribution
and age of types of vegetation were also recorded given the intimate
relationship which exists between the soil and the root system (Alexander,
1965). For example, if the type of vegetation natural to the area was
found, the soil most likely would be considered Native Soil, usually
reinforced by the presence of a combination of other indicative fa tor .
It Is likely, however, that mine waste may have affected the soil type but
not the natural vegetation arid for this reason careful consideration of
each soil sample was given in the office looking at all the samples
together, under the same lighting conditions. It was this second
descriptive process upon which the final classifications were based. Four
generalized soil classifications were delineated for the site. A
hypothetical stratigraphic column was developed based on existing soil
relationship at the site. The SOIlS can be described as follows:
1. Native Soil (NS): Undisturbed natural soil, native to a part icu-
lar area and not brought in from anywhere else. Varies from
alluvial terrace deposits, to glacial drift and colluvium.
2. Fill (F): Soil used as fill, may include dirt, stone, brick,
slag, glass, etc., but does not contain mine tailings.
3. Mine Tailings (MT): By-product of Smuggler silver/lead mine
operations. L1tholo t is usually silty sand, fine to coarse
grained, trace cinders, silt, gravel, pebbles, cobbles, gray to
black.
(004SF)
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3-6
4. Man-made Fill ( IF): Material used as fill, may IflCl d dirt,
stone, bricks, slag, glass, etc., and contains some mine tailings
usually Identified by their gray to black color.
Mapping of the surface soil conditions around the site was critical to
determine the lateral distribution of contaminated materials. Soil types
were characterized and defined fri the field and mapped on 1 “SO’ aerial
photos. Because of the construction activities and associated landscaping
around the area of the site, a low altitude fly—over was conducted as part
of this investigation. Color aerial photos were taken at different angles
for use in updating the soils maps to reflect changes at the site. The
individual photos were used to reconstruct a panorama view of the site at
a scale of approximately 1Ms280. Finally, all maps were field checked
for accuracy during and after the sample collection. This map series is
presented as Volume II!. It is important to note that contacts between
soil units are often gradational. The existing contact lines reflect
areas where one soil type predominates over another. A slash line between
soil types indicates that both units are present.
3.2 Subsurface Sampling
The subsurface field activities were needed to provide access to the
materials underlying the site. Visual observation along with chemical
analysis allowed the determination of the vertical extent of the mine
tailings and heavy metal contamination.
- 3.2.1 Procedures — Test Pits . Seven test pits were dug to sample and
Identify the subsurface conditions (Figure 3-2). The test pits were dug
with a backhoe and a professional operator provided by Ran Excavation,
Woody Creek, Colorado and were made under the direct supervision of a HART
hydrogeologlst. Test pits were excavated to a depth of 10’ to reach natur-
al materials. Test pit logs and stratigraphic columns were prepared for
each pit describing l1tho1o ’ and stratigraphy (Appendix D). The selec-
tion of the specific location for each test pit was based on various
combination of stratigraphic relationships of the different materials.
TP-l represented mine tailings over man-made fill over native soil. TP-2
(004SF)
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Ic* I (( I
FIUUM 3-7
TEST PIT LOCATIODS
BOREHOLE LOCATION
• T.sS P11 tocallons
• Toss •o,.I,oI. tocallon
Suilaco $.mplIn tOcaSSø 5
-------
4-3
the values obtained In the laboratory. Since the XRF may appear to
exaggerate lead values, application of the 1,000 ppm lead action level in
this case would insure that any error would be on the side of safety.
4.2 DistrIbution of Contaminated Soils
Table 4—2 shows the results of the surface s&nple analyses. Lead
values ranged from a high total of 15,925 ppm at GP-24 to a low total of
185 ppm at GP-21. Two other sanples, taken from GP-7 and GP-29, show lead
values In excess of 7,000 ppm. Values were 7,890 ppm at GP-7 and 7,615
ppm at GP—29. Six samples, other than GP-21, had lead concentrations less
than 300 ppm; GP—17 (290 ppm), GP-19 (218 ppm), GP—25 (209 ppm), GP-30
(299 ppm), GP-31 (208 ppm) and GP-34 (282 ppm).
Over the entire site, the four soil types of native soil, fill, man— ‘
made fill and mine tailings were mapped extensively on aerial photographs
(FIgure 4—1) (Plates 1—6). It was not possible, however, to delineate
every area in specific detail due to inaccessibility and/or complexity of
soil types. This was the case In the trailer part, where every yard or
driveway may have had a different soil type used as fill. Other areas
where complete mapping was not possible was in much of Jnter Creek Devel-
opment and other landscaped areas. The mapping performed was surficial
mapping and when an area was landscaped, the area was defined with a soil
type, such as fill, but given a qualifier of •r, for Probeblyu. These
types of areas were generally clean on the surface, however at a depth of
several Inches, contineted material could be encountered. Further
investigation can positively define these probable areas.
A composite map has been included in a pocket at the end of this
report volume. The map shows the detailed soils mapping, HART sampling
results, and CON sampling results, all referenced to the site grid. Soil
units containing mine tailings are shown in green, and soil units not
containing mine tailings are shown In red. This map provides the most
complete sumary of all soil mapping and sampling done at the site. For
blueprint copies, hatch marks can be used to identify different soil
types. A suimnary of the results of EPA’s geostatistical analyses is
presented in appendix H.
00l3F)
-------
TABLE 4-1
C ARISON OF XRF AND ROCKY MOUNTAIN LABORATORIES DATA
Sample Nwi ber Sample Type CDM RJ4I
GP-7 Grid Point 7890 3,770
GP-9 Grid Point 909 962
GP- 19 Grid Point 218 201
GP-24 Grid Point 15,925 19,700
GP-27 Grid Point 879 718
GP-31 Grid PoInt 208 90
1P6-1 Test Pit 298 9
TP3-2 Test Pit 5,540 1,800
(0239F)
-------
3
I C US I I
cm
S •SS 4 S
‘I
FO DETAILED SOIL CONDITIONS. EIIR TO PLATESI
soU E4- I
El
‘.1
M SØM Sd• Fill
M1.• TsIIin s
rise a aas... V
J ’)
MAP OF SURFACE SOt.. CONDIJIONS
-------
4-6
TABLE 4.2
RESULTS OF XRF LEAD ANALYSIS
Sam 1e Number Lead Concentration
;: dpof nts
GP1 560
GP2 648
GP3 553
GP4 348
GP5 802
GP6 391
GP7 7,890
GPS 611
GP9 909
GP1O 553
GP11 483
GP12 767
GP13 636
GP14 380
GP15 368
GP16 347
GP17 290
GP18 732
GP19 218
GP2O 657
GP21 185
GP22 660
GP23 709
GP24 15,925
GP25 209
GP26 539
GP27 879
GPZ8 450
GPZ9 7,615
GP3O 299
GP31 208
GP32 540
GP33 481
GP34 232
(0239F)
-------
4-7
Mapping was accomplished through physically walking over the area and
correlating soil units with high altitude aerial photographs and recent
low altitude color aerial photos taken during the course of the Field
Studies. Composition, texture and color defined the soil unit to which a
particular sample belonged.
Each sample was assigned a soil unit based on composition, texture and
color. Table 4-3 shows that each soil type has a characteristic lead
level. Average levels of lead concentration in mine tailings and manmade
fill were above the 1,000 ppm level. In every sample of fill and native
soil, lead levels were below the 1,000 ppm level (Table 4—3).
In samples GP—l9, GP—20, and GP—23, Mavm ade fill was present together
with mine tailings which contained less than 1000 ppm Concentration of
lead. The reason for this is that these samples of fill containing’
tailings did not possess enough tailings to reach the action level. This
is not a problem if that mapped unit is treated as contaminated.
Calculation of the Spearman rank correlation coefficient indicated
that the correlation between lead concentrations and soil type has not
an Sen by chance (Table 4—4). Since each soil type can be mapped by
visual classification and its typical concentration is known, the site
could be mapped at the 1,000 ppm isopleth by the definition of tailings
and margDade fill soil types with an accuracy of 99%. Rank values for soil
types were determined by assigning each of the 4 soil groups the same
average rank, depending on the number of values in that soil group. For
example, native soil was assigned the lowest rank of 10.5. The value of
10.5 was calculated by averaging the sum of 1 + 2 • 3...+ 20. The value
of 30 for fill was calculated by averaging the sum of 21 • 22 + 23...’ 38,
etc.
Wherever samples were collected from an area with high mine tailing
content, lead values were the highest. At GP—7, an area of ma,uade fill
containing mine tailings, lead values were 7,890 ppm. At GP—24 , also an
area of saomade fill containing mine tailings, values were 7,890 ppm.
Again at GP—29, an area of mine tailings, lead concentration was 7,615
(OOl3F)
-------
4-8
Sample
Number
Table 4-3
LEAD VALUE/SOIL TYPE COMPARISON
Sample Type
Mapped Soil Type
Nine Tailing,
Mine Tailings
Mine Tailings
Mine Tailings
Mine Tailings
Mine Tailings
Mine Tailings
GP-7
GP -24
GP-29
TP1 —1
TP2 .1
3-2
IB 1- 1A
TP4-l
TP S-l
GP- 12
GP-20
GP-23
Grid
Grid
Grid
Test
Test
Test
Test
Test
Test
Gri d
Grid
Gri d
P01 flt
Point
Poi nt
Pit
Pit
Pit
Boring
Pit
Pit
Point
P01 ut
Point
Lead
Concentration (ppm )
7,890
15,925
7,615
3,425
13,400
5,540
8,514
3,600
2,370
767
657
709
Manmade
Manmade
Manmade
Manmade
Manmade
Fill
Fill
Fill
Fl 11
Fl 11
GP-25
Grid
Point
Manmade Fill
209
GP-l
Grid
Point
Fill
560
GP-2
Grid
Point
Fill
648
GP-8
Grid
Point
Fill
611
GP-9
Grid
Point
Fill
909
GP-13
Grid
Point
FIll
636
GP-15
Grid
Point
Fill
368
GP-16
Grid
Point
Fill
347
GP-17
Grid
Point
Fill
290
GP-18
Grid
Point
FIll
732
GP-l9
Grid
Point
Fill
218
GP—2 1
Grid
Point
Fill
185
GP-22
Grid
Point
Fill
660
GP -26
Grid
Point
Fill
539
(0239F)
-------
4 j
Table 4-3
(Continued)
LEAD VALUE/SOIL TYPE COMPARISON
Sample Lead
rnmiber Sample TYP! Mapped Soil Tyn Concentration (pDm )
GP-27 Grid Point Fill 379
GP—28 Test Pit Fill 450
TP 1—2 Test Pit Fill 807
TP3—l Test Pit Fill 455
TP6—l Test Pit Ff1 1 298
GP—5 Grid Point Native Soil/Fill 802
GP-3 Grid Point Native Soil 553
GP-4 Grid Point Native Soil 348
GP—6 Grid Point Native Soil 391
GP—lO Grid Point Native Soil 553
GP-ll Grid Point Native Soil 483
GP- 14 Grid Point Native Soil 380
GP-30 Grid Point Native SoIl 299
GP-31 Grid Point Native SoB 208
GP-32 Grid Point Native Soil 540
GP-33 Grid Point Native Soil 481
GP-34 Grid Pot nt Native Sal 1 282
TP 1-3 Test Pit Native Soil 433
TP2—2 Test Pit Native Soil 600
1P3-3 Test Pit Native Soil 345
TP4—2 Test Pit Native Soil 894
P5—2 Test Pit Native Soil 260
TP6.2 Test Pit Native Soil 289
TP7.i Test Pit Native Soil 370
TB 1—2A Test Boring Native Soil 427
(0239F)
-------
TABLE 4—4
SPEA 1AN RANK CORRELATION COEFFICIENT
x y
PP Concentration (Dpm) Rank Soil Type Rank d
185 1 F 30 -29 841
208 2 MS 10.5 —8.5 72.25
209 3 F 30 —27 729
218 4 F 30 -26 676
260 5 MS 10.5 —5.5 30.25
282 6 MS 10.5 —4.5 20.25
289 7 NS 10.5 -3.5 12.25
290 8 F 30 —22 484
298 9 F 30 —21 441
- 299 10 MS 10.5 .5 .25
345 11 MS 10.5 .5 .25
347 12 F 30 —18 324
348 13 MS 10.5 2.5 6.25
368 14 F 30 -16 256
370 15 MS 10.5 4.5 20.25
379 16 F 30 -14 196
380 17 MS 10.5 6.5 42.25
391 18 MS 10.5 7.5 56.25
427 19 MS 10.5 8.5 72.25
433 20 MS 10.5 9.5 90.25
450 21 F 30 .9 81
45$ 22 F 30 -8 64
481 23 MS 10.5 12.5 156.25
483 24 NS 10.5 13.5 182.25
539 25 F 30 -5 25
540 26 MS 10.5 15.5 240.25
553 27 MS 10.5 16.5 272.25
553 28 MS 10.5 17.5 306.25
560 29 F 30 -1 1
(0239F)
Ic
tq
-------
4-11
TABLE 4—4 (ContInued)
SPEA 4AN RANK CORRELATION COEFFICIENT
x y
Ph Concentration (ppm) Rank Soil Type Rank d
600 30 NS 10.5 19.5 380.25
611 31 F 30 1 1
636 32 F 30 2 4
648 33 F 30 3 9
657 34 itr 42 -8 64
660 35 F 30 5 25
709 36 III 42 6 36
732 37 F 30 —7 49
767 38 rir 42 4 16
802 39 NS 10.5 28.5 812.25
807 40 F 30 10 100
894 41 NS 10.5 30.5 930.25
909 42 F 30 12 144
2370 43 42 1 1
3425 44 MT 48 —4 16
3600 45 42 3 9
5540 46 MT 48 -2 4
7615 47 M I 48 —1 1
7890 48 MT 48 0 0
8514 49 MI 48 1 1
13400 50 MT 48 2 4
15925 51 MI 48 3 9
d • 0.0 d 2 s 8314.0
Do’
11
- (0239F)
-------
4-12
TABLE 4-4 (Continued)
SPEA AN RANK CORRLEATI COEFFICIENT
x y
Ph Concentration (ppm) Rank Soil Typ Rank d
r — 1 — 6 ( d 2 )
n (n 2 —1)
r a 1 - 6 (8314 )
51(512_i) • — .62
132600
N • 51 OF N - 2 • 49
HO: Ps • 0 the correlation between x and y, I.e. their tendency to vary
together, has au sen by chance.
t. r • . 6 • . 6 • 5.36
_______ .62 —
N-2 49 49
Reject Ho tos • 2.0 t.01 - 2.68
The correlation between lead concentration and soil type has not arisen by
chance.
(0239F) ‘1
-------
4-13
ppm. Areas of native soil contained the lowest concentrations of lead,
while areas of fill and then manmade fill (containing tailings) show
respectively higher values, with mine tailing areas having the highest
values. Average lead values for surface samples taken In areas of native
soil were 443 ppm, 546 ppm when taken In areas of fill, and 10,477 ppm in
areas of mine tailings.
This trend also applied to subsurface sampling. Table 4-6 shows the
stratification of soil types and lead contents In each Test Pit. The
highest lead concentration values were found where samples were taken from
soil layers containing mine tailings only, or from manmade fill which
contained a large percentage of mine tailings. Other high lead values
were found In TP-l, TP-3 and TB—l, where samples were also taken from
areas rich in mine tailings. These values were 3,425 ppm in TP1-l, 5,540
ppm In TP3-2 and 8,514 ppm In TB1-lA. The lowest lead concentrations were
found In areas of native soil, the lowest reading beIng 260 ppm at 1P5-2.
Lead values were slightly elevated in the native soil below surface mine
tailings In one sample, 1P2—2. The Mann—Whitney U statistical test was
used to determine if a significant difference in lead concentration exists
between the surface native—soil and the subsurface native soil. The
U—test is used as an alternative to the t—test when the parent population
Is not known to be a normal distribution (Till, 1982). Calculation of the
Mann-Wltney U statistic Indicated that lead concentrations In surface
native soil are not significantly different from lead concentrations in
subsurface native soil (Table 4—5). This would preclude the possibility
of extensive leaching to the groundwater, and Is in agreement with the
l4inter Creek Soils Investigation performed by Engineering-Science
(Appendix F). In addition, It Is unlikely that leaching Is a concern on
the site due to the low permeability of mine tailIngs (SectIon 4.4) com-
bined with slow percolation rates.
Concentrations of lead increased from native soIl, to fill, to manmade
fill (containing mine tailings), to mine tailings. Averages were 452 ppm,
520 ppm, 2,985 ppm and 7,923 ppm, respectively.
‘1
(OOl3F)
-------
S —
.
5.0 CONTAMINATION ASSESSMENT
Determination of the nature and extent of remedial actions needed at a
site requires an understanding of the hazards posed by the site under
investigation. This chapter presents an assessment of contamination at
the Smuggler Mountain site based on this and other studies.
ce the type and extent of contamination has been defined, exposure
routes and migration pathways can be Identified. Endangerment scenarios
based on this data can be envisioned and examined to determine the risks
posed by contamination at the site to public health and the environment.
The appropriate level of risk reduction necessary for the protection of
public health and the environment can then be quantified Into an environ-
mental protection goal. The environmental protection goal Is used to
assess the adequacy of the remedial alternatives examined in the feasi- ‘
bility study contained In subsequent chapters of the report.
5.1 Type and Extent of Contamination
EPA has defined the boundaries of the Simiggler Mountain site as the
1,000 ppm lead Isopleth. Areas with soils containing higher than 1,000
ppm lead are considered as part of the site. It was shown that lead
concentrations are related to soil types. Further, it was demonstrated
statistically at a high confidence level that two mapped soil units con-
sistently contained higher than 1,000 ppm lead and two did not. The two
mapped units which contained concentrations of lead which were generally
close to or over 1,000 ppm were the mine tailings and the man made fill.
Since these two units reported lead concentrations generally over 1 ,000
ppm, they are defined as the site, and will need to be considered for
remedlatlon. The other two mapped units were consistently under the 1.000
pm lead concentration level and will not be considered further.
It should be noted that cadmii is also of concern due to its toxi-
city. Laboratory analyses showed that all samples with a high lead con-
tent also contained significant amounts of cadmlir and samples which
exhibited low lead also exhibited low cadmii . This finding suggests that
( OOl8F)
-------
5-2
lead can be used as the indicator parameter which determines if the sofl
is significantly contaminated with cadmium or not.
Treatment of the theory of lead Concentration in soil as a fUn tj of
the mapped soil unit Is critical in this Case. A composite map Showing
grid points, analytical data and mapped soil units are shown In the map
contained in a pocket at the end of this report volume. CDM’s pollutant
contour map is presented in Appendix H. Since the surface area of the
site is not homogeneous, Contour maps showing the 1,000 ppm lead (sopleth
which did not consider areal changes In soil type would not be accurate.
This is critical to a proper understanding of the areal extent of
contamination at the site. Contalnated soils have been moved and
scattered at random all over the site as lawns, driveways, and road base,
an Important consideration for remediation. Problems of m1s1eading
boundaries were avoided by careful soil mapping. The series of six de-
tailed maps which cover the soil conditions at the site are present In
Volume 111 (Plates). Conmion statistical analyses shows that an accurate
delineation of cont ninatjon can then be related to the mapped soil
types. Remedlation can focus on those units which are generally over
1,000 ppm lead, and the individual outcrops of those units.
5.2 Exposure Routes and Migration Pathways
Several routes of exposure presently exist at Smuggler Mountain which
could cause adverse effects if contamination reaches receptors. Direct
contact with the waste could permit exposure. Contaminant laden dusts
could be inhaled. WInd could carry fugitive dust particles Potentially
laden with contamination to nearby residential areas. Soil and pollutant
characteristics are an effective barrier to groundwater pollution fron
site soils (tailings and manmade fill). The risk to groundwater from the
site, then, Is minimal. Consequently, there Is a theoretical risk to
public health through Ingestion of drinking water contaminated by site
soils, but existing site conditions reduce this risk significantly. Since
(00 18F)
-------
5—3
previous studies have Shown no Contamination of surface water, surface
water will not be considered here.
Studies to determine whether there may be groundwater contamination in
domestic wells near the site have been inconclusive. The possibility of
contaminated groundwater, if any, emanating from the site may exist.
Although elevated levels of metals in wells could be indicative of ore
deposits, mining operation, or well construction materials, they may also
be associated with the Smuggler Mountain site. Future groundwater de-
velopment in the area could be limited by the Occurrence of this contami-
nation; however, future use of this aquifer is Inhibited by the control of
development in Pitkln County.
5.3 Endangerment Scenarios
Haying enumerated the threats of Contamination posed by the uncovered,
unstabilized tailings and mixed soils at the Smuggler Mountain site, this
section will proceed on the assumption that the site poses routes of
exposure through air and direct contact, and a potential threat through
the medium of groundwater. A complete discussion of the difficulties with
evaluating the potential contamination of groundwater was developed In the
FF5. This discussion is reiterated below.
As the geological description of the site indicates, the fractured
bedrock underlying much of Smuggler Mountain contains mineralized zones,
several of which were mined. Regionally, rain and snownelt percolating
down the Interior of the mountain forms a horizontal flow downgradient in
the direction of the alluvial aquifer in the valley. It Is likely that
water In the bedrock aquifer percolates through the mineralized zones and
through the abandoned mining areas as It travels to dischargeS into the
alluvial aquifer below and dcwnslope of the Smuggler Mountain site.
Hence, arw metals found in the alluvial aquifer may be due to the trans-
mission of heavy metals from the bedrock inside Smuggler Mountain, a plume
of contamination from the Smuggler Mountain site, or some combination of
(OOl8F)
-------
5-4
the two. best, this combination would be impossible to evaluate due to
the inability to obtain data regarding upgradient background conditions.
Potentially, as rain and snowmelt continue to percolate vertically
through the Smuggler Mountain site, the site could eventually have at
least some role In contaminating the alluvial aQuifer downgradient of the
site. It should be noted, however, that acid-base studies showed no
potential for acid mine drainage, indicating that leachate percolation at
the site would not become worse than it Is now.
5.4 Environmental Protection Goals
The overall goal is to minimize the actual or potential release of
hazardous substances Into the environment from the site. Where direct
study allows for a precise identification of those threats, both actual,,
and potential, precise remedial steps can be taken to arrest contamination
through available media, as in the case of air direct contact. Where such
identification is confounded by geological ambiguities, as In the case of
groundwater, means of abatement must be undertaken co1 ensurate with
reasonably established parameters of potential harm.
The specific environmental goal for the Smuggler Mountain site is to
Insure the protection of the health of residents in the area. Goals for
the mitigation of surface releases have been established by EPA In the
form of a risk assessment. EPA has defined the site boundary as the 1 ,000
ppm isopleth. All soil containing higher than 1,000 ppm lead must be
Isolated such that human health and the environment will be protected.
Specific environmental goals with respect to groundwater are to mitigate
the threat of exposure to present and future users of the groundwater
supply.
/
- (001 8F)
-------
Smuggler Mountain Mining Waste NPL Site Summary Report
Reference 3
Excerpts From Soil Clean-up of Smuggler Mountain Site,
Aspen-Pitkin County, Colorado, Explanation of Significant Differences;
EPA Region VIII; March 1989
-------
Admiriustrat,ve R.cor
.P File NuTber
In. t
0222400
Region VIII
Superf’wid Program
SOIL CLEANUP OF
SMUGGLER MOUNTAIN SiTE
ASPEN-PITKIN COUNTY, COLORADO
EXPLANATION OF SIGNIFICANT
DIFFERENCES
________ MARCH 1990
OVERVIEW
r ’r,u ’ns ul the Smuggler Mountain Site in Aspen.
l’urkiii County. Colorado, are ct,ntnmtnsted with
mining wastes, which contain high concentrations
ol lead and cadniuum. These concentrations pose a
puientuol health nsk to humans, especially small
children arid pregnant women. Consequently, the
!: e placed . the Eiiv:ronrneatal Porec ori
AgenCVS i EPA) National Priorities List for clean
up under the Comprehensive Environmental
Response. Compensation. and Liability Act (better
known as CERCLA or Superfund). Under the
Superfund luw, EPA is charged with the
responsibility of developing and implementing
cleniitip reniedies that protect human health end the
environment.
After thorough StUdy and evaluation. EPA issued a
Record of Decision in September 986. deacnbing
the remedy chosen to clean up the site. This remedy
was subsequently changed because additional
sanipling results caused EPA to question the
iiiipknientability of the clean-up plan. Changes
were reflected in EPAs Match 989 Explammon
of Significant Differences, a document which
described differences between the remedy proposed
in the Record of Decision and the remedy to be
urn pleiiiented at the sate.
Aspen residents and local officials expressed
c’ncern with the changes and submitted to EPA an
.iltermit,ve proposal for site cleanup. Given these
concerns and the results of additional soil sampling,
EPA decided to make further rev,ssnns to ihe
remedy. The revisions affect four primary
curnpunents (I I on-site reposac ’ry, 12) cIe ii up r ri
individual residential properties, t3i remedial
action at Hunter Creek and Centennial
Condumumums. and t4 institutional controls
The community us invited to attend one of the
scheduled meetings desvrtbing the l99U di4ft
Explanation of Significant Differences to be held
the week of March 19. 990, in Apsen The
community is also invited tn submit w,itten
commerra to EPA by Friday, March 30. IQQ()
Major chanr, to the rsmeds proposed In iii I ’
draft Explanetloe ofSlgniflcant Differences are as
rolIo w
I. The number and size of the on-cite
repoeftorle needed for the dtsposai of
contamluated soil may be reduced.
2. For individual properties, the protective
cover 01 clean soil to be placed over
contaminated areas will be reduced fnu,ii
2 feet to a po4eztIIe liner overlain with L
foot ol dean sot
3. For the Bunter Creelt and Centennial
Condondalems. the protective cover of
cleats soil to be placed over cossti.miui.ied
arw wil be reduced from 2 feet to 6
4 Mon atlls4IId institutional controls will
be implemented to ensure the
effectiveness and permanence of the
remedy .
These dia.tpes are descrthed In detail m this
Explanation o(Slgniflcani Differences.
-------
0222401
SOIL CLEANUP OF SMUGGLER MOUNTAIN srr
ASPEN-PITKIN COUNTY, COLORADO
- DRAFT EXPLANATION OF SIGNIFiCANT DIFFERENCES
March 1990
CONTENTS PAGE NO.
INTRODUCTION 2
SUMMARY OF SITE HISTORY AND CONTAMINATiON PROBLEM
SfteH tory 2
Background on Lead and Cadmium Contamination 3
SUMMARY OF THE I 999 RECORD OF DECISION (ROD) 3
SUMMARY OF THE 1990 REMEDY
SIte Boundary 4
JustificatIon for Chargina the Remedy 5
On -sIte Ppository
Cleanup on IndMdUaI Residential Properties 7
Remedial Act n at Hunter Creek and CentennIal 9
Condomintums
Institutional Controls 10
Protectivenses of the Remedy 12
EXPLANATION OF SIGNIFICANT DIFFERENCES 13
SUPPORTING AGENCY COMMENTS 14
STATUTORY DETERMINATIONS 14
SCHEDULE FOR SAMPLING AND CLEANUP 18
PUBLIC PARTICIPATION 10
-------
INTRODUCTiON
I lis i a drThIt E;plannt.on of Signiflca,it
lPiITer,, tES [ H on htcIi the E,tv,roiintenrn l
L’roieviiu,, , envv (EPA) will be taking
co’iiinems frog,. Mardi 8 through March 30.
1990. EPA will consider wrItten cus.ime,,ts fron.
the public and will reipond to signiflca.it
cmimients recened in a suiim ry report to be
Lvwed at the lime the FSD Is made Anal. The final
£SD us scheduled to be published by Apnl 15.
1990.
The purpose of this document is to explain the
sugiiificant differences between the Record of
Decisiuni ROD, signed by the EPA in 986 iwh,ch
was subsequently modified by a prev ous
Cxp’tnnat.uu , of Significant Differences in Marcl
i J Q and the remedy ei prnposed herein, which
will be implemented at the site.
The ROD divided the site into two operable units
(OW #1 Residentialareas including the site of the
ie ,siiniy or the Mullie Gibson Park and #2
Smuggler Mine sure. The ROD selected a remedy
t nh toi OU #1 The previous ESD and this ESD
int address changes to the remeth selected for OU
HI AremedywillnotbeselectedforOU#Zunt ,la
ieniedial investigation and feasibility scudytRl/PS
is completed fur the mine site.
Under Section 117 of the Comprehensive
Environmental Response, Compensation, and
Liability Act of 980 tCERCLAI, amended by
the Supuerfund Amendmenti and Reauthorization
Act ut 986 (SARA), EPA is vequu’ed to publish an
e punatiun of significant differences when
sign.ricant, but not fundamental, changes are
proposed to the previously selected remedy. This
document provides a brief history of the site.
describes the remedial action to be undertaken at the
site, and explains the ways in which this remedial
acinin differs from the remedy selected by EPA in
1986 and subsequently modified in 1989.
This ESD presems only a synopois of information
on the site. The final ESD will be incorporated into
the rtdniinistrative record file. The reader may wish
ii’ refer to the previous ESD issued in March 1989,
which is available at the Pitkzn County Library and
4, ’
2
at the Aspen-Pitkin Couiic Enviio, ,me,ir fe3liII
L)epa -trneiit.
Siti History
The Smuggler M’unta,n Site ithe sitei I ‘a
Aspen, Pitkin County, C ’lnrado The old Sin,, £gter
mine workings are located at the base at the westel ii
side of Smuggler Mountain.
Waite rock, tailings, and lag frrim Smuzgler mine
cover much of the site. The mine wastes ire either
exposed,covered,or, in many Instances. mu *ed with
native or imported soil. Due to it luvali in in the
resort town of Aspen, some residential deveIopi ent
lia.s taken place immediatels on top of these waste
piles. In addition, some piles have been leveled ur
moved to the edge of the developed uress where
they now remain as berms o(contai ,iuiiutej snil
The site is approziniarely 90 percent ueveio ed
Development includes two laige cousdtmiiiiitiii,
complexes. approximately 160 ,nd,v,thml h ’iies.
several small or condominium developmeiics 4- L
unitsi, and a tennis club.
Soil analyses in the early 1980s. conducted lust h
residents, later by EPA and the pvtentialR
responsible parties (PRPs’,, identilied
concentrations of lead up to 46,000 parts per , i,ll
ppmt. Elevated levelsofcadmium, as well .j oilier
metals, were alio found in the soils. The potential
fi,r ground water conranuna lson was also identifled
during the investigations. The site was propi ‘setl Ii ‘r
the National Priunties List tNPL.i, the Superfund
list, in October 1984. Lissiuig was final in 198ö
In 986, EPA selected a remeth for soil cleanlir ’ at
the site. During the design of the retneds. EPA
conducted additional soil sampling at the site to
determine the necessary capecity fur the on•site
repository. The results of this additional soil
sampling, which was conducted in the stinirnet of
1q88, indicated that the remeth selected iii 1986
needed to be changed.
SUMMARY OF SITE HISTORY
AND CONTAMINATION
PROBLEM
S.-
-------
A
Iii Match 1989. an initial SD wa diafteti and
presented to the Aspen conirnunitI. The residents
had itiaioi concerns regarding the exten 3nJ
ii i , ,ii ,pde tif ihe ‘ e’ ,,e J,ai action 1li tr conce, us
iet .iteiJ die at.cu i esigti and unipleinernart n o
cite, entecj’.. cite estimated cost. evidenceof art actual
health ,‘ k and tite,, pc tencial tiabilits. as defined
under (. RCLA
Throughout the spring and summer of 1989. EPA
met with local officials anti citizens in an effort to
add,etq then concerns EPA received a i .imizens
rrr rosnl through Pctkin County dated June 28.
I’J*9. which proposed an alternative remeth which
cjuiIered (mimi the one presented in the 1989 ESD.
Flits proposal also included a request for assurances
liii, l:PA iegarduiig the resttiencs pntenhial
liability Discussions occurred between EPA and
he (. ‘unt concerning the cmcmzens proposal. The
i enieth jwnposeci in this ESD addresses both EPAs
concerns about the impracticality of the 1986
i emetly anti. to the extent practicable, concerns
expressed by the citizens about the reniedy.
In the disct,sssons between EPA and the
community, other issues wee identified which will
not be addressed in this ESD. Design issues, such
as preservation of ue# or the soil sampling of
individual prnperttes. will be addressed in more
detail during the design phase of the pruject after
rime St) us final Other issues of conceni to the
residents, such as statutory contnbution protection
anti the potential deletion of stewtory reopener
clauses, would be addressed as part of any
seulenient between EPA and the property owners.
Finahib, del sting of the site from the NPL will be
addressed in more detail after completion of the
reniedy.
Background on Laid and Cadmium
Contamhiatton
The pnmar health risk at thesiteisthe potential for
huinaii exposure to lead and cadmium through
direct contact with mine wastes and contaminated
soils.
Lead is a lieav metal that is associated with the
nit nC wustes fi nind at Smuggler Mountain. Lead can
be tilisrirbed by humans either through breathing
dust in the air or inadverenth. Because small
cli , kit en tend to put things in their mouths. clii di i
no live near a source of le iJ pollution ate atoce
ikeh to be exposed to lead than adults
Fqw’sure to lead ma cause long.’ernt intl
permanent damaie to the nervous S% Steln. which
ina esuht in learning disabilities and hemi,iviccrai
problems in chuidien Even at very low Iecefs. leud
e pusure cat, cause haruiful effects to the iie vous
system in childien.
Lead exposure may also cause k’n -teriii clainage tc
the cardiovascular s sueni, rhei eprcidtict ,ve s’. steai.
the kidneys, arid the live Lead has been situ” Ii tcj
be carcinogenic itt annual studies
C ’adniium is a heavy metal that is also as nciaced
with the mine wastes found at Sniuugglei- Mountain
Studies have shown that cadnimtitn rna be
carcinogenic to humans. Exposure to cadmium can
cause lung-termeffectscn the kiuinecs. bones. liver.
and respiratory and immune s stems. Cadri ium
may also adversely affect liumnami reprotluctioti
Plants, including leafy green vegetables and root
crops. may uptake cadmium from cu,uuam,naued
soils. In addition, vegetables collect dust. cwlitLfi Is
not easily removed. “egetables gic’wrm in
contaminated soils may present an exposute Lu
humans who consume those vegetables
-I
The objectives of the remedy selected in the ‘986
ROD were to isolate waste nuatenals with lead
concentrations greater than 10 1 )0 ppm by requiting
U excavarionand disposal of sc ,il&,l u lmngs with lead
concentrations greater than 5000 ppm in an on-site
repository, 2) capping of soils with lead
concentrations between 1000 and 5000 ppm with 6
to 12 inches of clean soil and revegetation. i
continue monitoring of the groundwater, 4;
provisionufanahiernatewatersupph f yi residences
w,th domestic wells, and ii uperamiiii .ittd
nunintenance of the remedy through regular
inspections as well as through insututiumil cviii , ohs.
The 1986 ROD selected a soil cleanup level lot leuci
concentrations of 1000 ppm based on the
0
SUMMARY OF THE 1986
RECORD OF DECISION (ROD)
-------
(.ie.2 J4
,,ife’rmatit’n in the Endangerment Assessment and
ih RLTS reio, t and on the recommendation In the
Agenc% frr Tovc Substances and Disease Regtstr
.\ISOR to EPA.
The rei d i- mn% refer r the ROD fors rnt ,e detailed
di’cucsn’n 4 f the remedy selected in (986. The
ROD , av %,I(.( le ,t the Pitkin Counts Librar and
it the Aipen-I’itki a Environmental Health
L)epu’ tinent.
The (989 l SD has been superceded by the remedy
proposed in this ESD. Many components of the
remedy proposed in this ESI) have not changed
frossi the 9*9 ESD. It will be noted in the
discussiuns below whether a component has
changed from the previous remedies. The havi es
will be noted at the end of a paragraph h . 1,racke’.s
L J and lsighlighhug.
Before desci-ibing the components the ‘,t’gvseJ
reméth, an explanation nf h w the site Ix,u,,dars in
E*hibit I was determineci and a disctissu’n rif the
factors that led EPA to make changes to the seleucd
remedy will be provided.
Sits Boundary
The proposed remedy addresses the re ’den.uil
areas within the site boundarii forOIi I I which ako
includes the Mollie Gibson Park repository. Ezhahtt
I of this ESD shows the site boundars which has
been drawn to conform to the prupertb buundai ies
of those properties on the border •‘I the
contaminated as . The site boundar is considered
an administrative boundary that defThes the area
subject to the institutional controls adopted by he
County.
SUMMARY OF THE
PROPOSED 1990 REMEDY
Stt’ w v
?0 —‘
— —
£thibã#I Site Boundary ‘fap
• t grin — it?,
.
‘V. 17 W )
4
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0222405
ini;iling h lir wn lend cornam,nnrinn gtetner
itj sj ‘vn in the soils on the properties at the
e i e • F lie site These pu peitIeS have been
iptI d uripii, rh pr hr iincla, ‘. Because the site
‘,uridai has been diawrt to conform to the
hi’iiini ,ii es . ‘i these pmperties, it may appear that
the i.,,ig,r aI uce ,otiiid. r’i. has expanded in some
aieas Additioii.ih soil sampling during the design
r’mse ma be necessar for some properties to
Jeinuf the contaminated portion of the property
th.ti uild ret u,re remediauon
Justification for Changing ths
R.m.dy
Previous nvesrigations conducted at the site did not
cleark identify the exact areas of soil
cc’iIWnhination In addition, the volume of material
ii ’ be e cavmed and buried in an on-site re . sitory
ii e. so,l with lead concentrations greater than
cIMMI ppmi was not fully known, since previous
Ii lvestigmis)iis had iiut sampled at depth.
Ilie results of the pee-design sampling conducted
l,s Fl’A in 1988 indicated that the volume of
material with lead concentrations higher than 5000
p rni was sign. ricantly greater than the capacity of
the Mollie Gibson Park reposgorv. The results also
indicated that both the areal and vert I distribution
‘f lend cuncenuat,ons in thesoilwtailings are highly
variable. This vanability in lead concentrations
made it impractical to calculate exact volumes
needing to be excavated. The variability also made
it extremeR impmct cal to impIenient two different
approuches (or soil cleanup, ti.e., total excavation
fur soils 50(K) ppm v . soil capping for soils
IUtKJ-SUUO ppmj.
lime 1 9 *9 ESD required 2 feet of clean soil with a
egetative cover for areas where lead
ci’ncentrati(,m s were greater than IOUU ppm. In
ninny situations, achievement of the 2-loot soil
cover would have required excavating 2- feet of
contaminated material first, before placing 2- feet
of cleats fill and topsoil. Based on the 938 soul
sanipling resulu and the requirement for a 2- foot
sail cover. EPA estimated that the volume of
inutet nil to be exuavaueuj and buried in an un-site
repository ranged from ‘5,000 to 85,000 cubuc
.iids A second on-site repository would have been
required to accommodate this volume of material.
4-
The res,denr and local offhials expre e l ct’nce”i
about several components of rIte 1980 retimeiji,
1 heir iliasor c(’ncerns uitclu Jed the anI ’u,Ii ‘
e scavariu n. the resulting c.listtii hance to The
community, and the need for two On-site
repositories EPA considered the 2 .f ,ot soil cover
in the 1989 renieth a necessary balamice between
engineering controls and institutiviial Cuiftrt’l .
because some contam,natit,n wotmkj be left tuii- it
The citIzens proposal subniiuicsi to CPA iii June
089 suggested an alternative balance that would
still provide protection ot human health and the
environment, 2 nhin,inize the need fai a seiuiid
on-site repository, and t provide mere cerinint’. in
calculating the volume of excavated fl latei,dl
requiring on-site disposal.
EPA is proposing revisions to the selected rented’.
given the flndiiigs ul the soil suniphng. the need to
address the impructzcahity of the 986 reiiueth, .i U
the concerns expressed b the citizens abtiuit the
remedy in the 1989 ESD l PA is pruiposing the
following changes to the remedy The pru ’useuA
remedy cunsisu of four majui elemenu.
O’ fteRepc ftory
2. Cleanup on Individual Resideimisal
o rtIea
Remedial AcUoui at Hunter Creek &
Centennial Condoinhawnis
4. Instifutloand Contro&,
I. On-else Rapoeflory
• An on-site repository will be constructed at the
MoHie Gibson Park Site with a design ca ’ncit’.
of approximately 35.000 cubic y.irds This
repository will serve as the primnan l’ucauio,i br
disposal of contaminated soil/tailings
excavated during the residential cleanup
Access to the repository will be cuntiolleuA b.
the County.
• The Mohlie Gibson Park repository will also
serve as the ‘open repository for disposal of
coinaminsted soth siIinp displaced due to an’.
kind ofdevelopmentofthe properties wiihii millie
site boundary after completion of cleanup
repoeltory at the MolDs Gibson Park Site
was ens’lsloiwd In the remedy in the 19R9
ESD. flowerer, the primary purpose of
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5
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0222406
reposilor sS IIISMOIIleGD,SO,I Park was for
fulere disposal after completion u t he
ruisedlal adiusLj
ihe Salvation Ditch lnigauon pipeline, which
urrenals passes direi.ih’ through the Mullie
(Jibsun P:irk site, will betetocated. See Exhibit
2 in this ESD. The pipe itself will be upgraded
to withstand thi expected additional weight
from the materials placed in the repository and
the pipeline will be re-aligned along the outer
edge of the lower bench of the repository for
future access. (The relocadon at the pipeline
has not changed (runs she L $ £SD.J
The Mnllie Gibson Park repository will be
constructed to be structurally stable, to
minimize surface runoff, and to prevent
unauthorized access. The open portion of the
iepositnry will have a temporary cover to
minimize dust and a fence to prevent direct
contact with the contaminated materials.
Exhibit 2 Piuposed R.Itscmin o’f Se1 ion Ditch
‘I,
• The clean fill and topsoil used as cap niaceritl
for the repositors will have lead concentrat, i
of 254) ppm or less. (This reqssirenwne lu. iws
been changed Irons the remedy in She (989
ESI)J.
To conserve the capacity of the ‘open y nu’n
of the repositor , the County will encourage the
containment of contaminated soil/tailings i’n s
many properties heingdevek pedas possible b
adniinisteri,ig local ordinances.
* Containment of contaminated suiVrnilitigs on
future properties wi l$ be accomplished ihsuugh
one of the following approaches:
I) Designing
minimize
contaminated
the devek’pment project to
the displacement or
materials, or
2) Relocating the contaminated materials
on the property being developed ‘bad
covering the masenals with an aprruved
cover that is in compliance with the
remedy. Any decision to dispose of
contaminated materials on the pn peTt will
include consideration of the arnoumli r f
material being relocated, the surr nnding
topography. surface runoff petterns and the
effect on adjacent properties.
• A second On-site repo’itorv nia’ be ncar’.
depending on the amount of cnniaiiti,iaied
soiI iIinp to be excavated during cleanup.
The proposed location of the second repusiwrv
is the Smuggim’ Racquet Club pruperts . A
major design goal during the clesnup will be to
minimize the volume of suiltu be excavated and
moved, thereby reducing or even eliminating
the need for a second repository.
• The decision forasacondon-siterepositir% will
be based on the number of properties to be
rernedjated and the volume of material to be
excavated from those properties. ‘this decision
will be male late in the summer of I’I’ I, when
allot the soil sampling and volume calculations
have been completed.
• Because of proposed changes to the rented in
thisESD(i.e..thecbangeinthesui lcuci depth
from 2 feet to I foot would result in a reduction
fXZZTZ,4 smt,rarW.
% . .
p ,.
c i ’ .
—
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0222407
of volume of material to be e c vare Jt. the
likelihood of a second repositor)’ is reduced
s lf,i econcI on-site repositoll. ‘S necessar%. the
SIZC ind C p Cit . would be sign lficancl% less
than the repository envisioned in the l9 9
,etneth It is hoped that, the second repository
wc .t ,kj no ’ “ecessitate Jisturbatices of the tennis
u’utts at the Smuggler Racquet Club
The berm separating the Racquet Club and the
Smuggler Mobile Home Park will be
reniedioted and vegetated whether or not a
second on-site repository at the Racquet Club is
necessiirv [ Remediallon of the benn was
always * component of the remedies
previously seleciedj.
2. Cleanup on Individual Realdentlal Properties
• Soil sampling will be conducted prior to
iniunnng remedial action on each individual
esidentini propert% that is not part of the Hunter
Creek or the Centennial developments.
• Sampling will be conducted in the w’p I fort e lf
SOil to detern,ine ii the existini soil co et u .s
lead concen(racio, , greater than hi *) i’ i ”
[ Soil sasnplina will provide EPA w;t 1 (lie
alisiIiv to calculate accurately the voIi of
soil to he excavated and dl1 pi e(j of in the
on—site repository. Additional detnii in , tlis
soul saisipliiii prut_nutis will be provided to
residents early in the Spring of 1990.1
• Properties where sampling shows se i Ie,J
concentrations above l($. )ppni wi ’ukl he (tilk
remediaced. as described below The w I
cleanup on the individual prupenies incIttde
the following components. (See Exhibit 3
showing the components of the retneds
A geocexcile liner coveted with I foot f
clean fill and topsoil isettled atiti
compacted and a vegetative cover to
minimize erosion is required for all ai, eas
not paved or covered h’, pernhiuiie ’Ic
strucwre. A geo-cexttle liner is a
£thib 3 Typical R.nicdy Compocunu
rReiSeø bed
\ garøen
‘ l v ’
LJ
18 Clean sail t’2
- I
Gras 7
House
\Pavement
7/7/ /7/7/7
Giatexti Ia
1:2. //
Geotextile
—Cor itamtnated
mater
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O222 . 0E
mnn .rnade mntennlts,milarro fein that will
be laid over the conramuiuaied soul&’tailings
I lie geo—te tile liner ‘ S 1)01 a
o.Itp4me , ,l oS Ike remedies prevnnislv
celected. [ he requiremnemit Cur the I-foot
soil co er is a chnna, from the 1989
I eniedv ‘rluicli required a 2-Soot soil
cut er. The flriginal 98 ren ,edv
required 6-Li Inches of clean lop oil for
soils with had coneen lraliuns ranging
null, IIM)O -5000 ppm.j
The pwpo e of die geo-iexule liner is to
pievent muting of the contaminated
iiiaterials with, the clean flu Also, the liner
will serve to alert property owners that
excavation below this liner would require
approval from the County The geo-teztile
liner with the I -foot sod cover functions as
a harrier to break exposure pathWaYS and to
prevent direct contact with contaminated
inatenals, thus protecting human health.
-(EPA hefteves that the geo.lezf Ii . liner
plus a I-foot soil cover will achieve the
saute goal of preventing the ndztng of
clemin soil with conIan nat d sod that
ttnnld be achieved with a iuui soil
Ahiclean rillandtopsoiliisedasbackmhjn
the residential areas will have lead
concentrations of 250 ppm or less. [ This
requirenuens has not changed from the
1989 reniedy.J
Paved areas such as sw o , driveways,
pnuus. parking areas, and sports facilities
provide on adequate coverto prevent direct
conta.i with any underlying contaminated
sui I/tailings. Driving ateas on the site, such
as streets and driveways. that are currentl
i n paved will be paved to prevent direct
contact. (The 19$, remedy allowed
gravel as weH as paving. However, gravel
it .ini as permanent as paving. Dust
leseb sire usually greater wlih gravel
surfaces.J
/
-1
Permanent structures such as single family
homes, condominiums, modular homes,
garages and other structwes with a hluor
arid foundation provide adequate cover for
preventing direct Ci iit
Contaminated materials e
modifications to these structuies that iii i nr
increase the ‘isk for d’vect c1.,IIi.iLt ili
Cflnt;inhina(ed materials Wotiki ieqIiirr ‘r? !r
approval b% Pitkin Counts a pair of lie
mnstiLut lonal contiols tt be init’le,nente ’J .is
part of the remeth (This cnnlpo.Ieiis lii.s
nut changed frtni , the 1989 re ,ned .J
Access tinder an home, deck, or ciitiiljr
structure will be hinitted or the ni.ice, ak
adequately covered to prevent the pt’tetiii.tl
for direct contact with contaminatej
materials [ This component has iwi
changed from the 1989 remedy.J
Where topographical condititirts permit.
contaminated motenals ma be ci,vered
in-place with a geo-textile liner, I foot of
clean fill settled and compocteiji, zu ii a
vegetative cover to minimize ert’SR’n
l’rnctical considerations such as rite
drainage patients and preservatioi , til lai ge
trees, as well as discussiuns with ahfeue ’J
property owners will determine mite
appropriate approach durnii cteai’i’o
IThis coniponens has only chaisged from
the 1989 ESD with, respect in the
required geo-lextlle and the thiuckiiess of
the soil cover.J
Undeveloped loc will be covered wnh I
foocofcican fill overa geo-cextile hue, md
revegetated with a natural grass mnixiure
Other acceptable covers that provide a
procectivebnrnerandareapprovenih EPA
may be substituted. Dunng construction or
the remeth, EPA will work with propei-t’
owners to the extent possible to
accounmotlate the owner’s plans f i
deveiupnveni. where those phinsm.iiui loi iii It)
the remedy. (This coniponeni hia m ,lv
changed from the 19*9 ESD with respect
ho the required geo-lest lie and ihie
thklussss of the soil cover.J
• All flower and vegetnhhe gm’ciens will he
replaced with raised-bed gardens that are it
least 6 inches above die top of the soil and
vegetative cover The piurp.’se of
raised-bed gardens is to provide a total f
8
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4
at fenst 18 inches of clean snil that will h
ensure that an adequate harrier exists
I’et een the mocs of vegetat’les and ans
cc ntanitnateti materials and 2i minimize
luetluelit digging below the top I foot of
LIeun soil [ TI,. requlreme ,ut for
aic 4 .bed zardein * new component
i, he prol,o ed remedy due to chang$ng
the required soil cover depth from 1 feet
t , i
- All residential areas WIll be restored to their
otiginal condition to the maximum extent
prssible. Since preserving the large trees is
a major concern to the residents on the site.
‘pectal care will be taken during cleanup in
working around the trees. Because
epincertient in-kind of large trees is very
eu rlv and not ilwa s possible. efforts will
be made to protect the existing trees. For
ii.aIIei- trees and bushes it may be more
cast-effective to replace them rather than
work around them during construction.
[ Thit component of the proposed
remedy lies not thang.d (ruin the 1989
reined .J
• Additional information and design details
regarding the treatment of trees will be
devekped diinng the design phase with
opportunities for residents’ input.
Those properties where sampling of the top I
footuf soil does noisbow contamination greater
than I ( iOU ppm may still requite same remedial
action to inert the minimum requrements of the
reniech In addition to the I-foot soil cover
aIreacI’ in place: the minimum requirements
include a healthy vegetative covert paved
diiving area raised bed pudens and limited
access under homes, decks, and similar
structures. -
During remedial design, EPA will evaluate
each property where sampling does not show
cuntasitination in the top I foot for compliance
with the remedy. It a property is not in
ct’mpliance with the remedy , those dcienues
will be addressed during the cleanup. Fur those
properties where soil sampling shows no
tu’iiinnhinat,i’n in the top I fool of soil,
ewavatiun of the property would not be
required, hence, the geo-te rile luiter wu’tild uuu,t
be pnrl of the remedy on that pi ’pert
3. RemedIal Actlo at Hunter Creek &
Ceiiteriiüal Cuiidonu,,iiiins
The propr ed remedy at the Flunter Ceek and
Centennial Condominiums differs somewhat fit,,
that at the rest of the site There are severul i easuns
for the these differences in the remeth
flrst. property ownership at the Ilumei Creek aid
Centennial Condominiums is unique in that access
and usage of the common areas is airead’. littited
by the condominium reguiutiuns. i e . declatati ”is.
by-lnws. and association rules. Second. the grounds
at theconiiominium areas i including the I4iid’ aueU
arid paved areas which cornpiise the cover, ac
maintained by the property management
associations.
Activities such ns individual gnrdening ciher than
in cuniatnersi and use of the hiwi,s lur ievreat ’L inii
activities such as soccer or foothaih that would
tend to be detrimental to the sod cover are currenik
prohibited by the condominium association niles
Third. although condomir.ium regulattc ns cot, Id be
changed to allow other uses, making those hiauges
involves the collective decision of the group u aiiier
than the decision of one individual owning the
property, as is the case with the ,uiividudl
residential property areas.
Finally, maintenance of the comrni’n arens I’. the
condominium asaocianons will also be required by
the County’s proposed ordinances.
When Centennial Condominiums were
constructed, must cuntaminated materials we, e
relocated to the Mollie Gibson Park site
However, soil sampling results in t 88 and
1989 at Centennial Condominiums show some
limited areas where contamination greater thait
11 )00 ppm still exists in the top 6 inches of the
soil.
• In 9*3, a 6-inch soil cover was applied at the
hunter Creek Condominiums. The 1988 and
989 sail sampling results at the Hunter Ci eek
Condominiums show that in many areas Ie id
concentrations are greeter than WOO ppni in the
top 6 inches of the soil cover.
9
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4,
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• The cause for failure of the soil cover is not
known since EPA did not conduct oversight
Jut ng construction at etcher the Hunter Creek
ot Centennial Condominiums The lack of
,1(llletenceto suict CL ’nscructlon standards in
cunsti uction of the so’ I cover mas be one of the
causes lot f4ilure of the soil etjver
• Most of the components of the remedy
described fur the inih v,dual residential
pr enie1 will be the same for the Hunter Creek
and (. enienuwl Condonuinums. The following
di usston i ii the snil chenntip remedy at the
hunter Cieek and Centennial Condominiums
will iitdude o,tl tinise cunipunents that differ
tiutti the individual residential properties.
• Six t6i titcites of clean topsoil settled and
criflipacted) and a vegetative cover to
siiiniiuize erosion will be required for all
are not paved or covered by permanent
Structures. LTl iIs component has changed
- from the 19*9 remedy which required a
2-toot soil cover. The (9*6 remedy
required l2 Inchee at dean INI and
I—.’
• Areas where the soil cover has tailed will
be repaired such that an uncumaminated
6-inch soil cover after settling and
compocciont exists at all times throughout
the Hunter Creek and Centennial
condominiums properties.
• Recausea 6-inch soil cover is proposed for
the condonurnums instead of the I -(oat soil
cover required at the rest of the site
additional institutional controls including
certain access restrictions on common
areas will be implemented. These
additional controls will be discussed in
more detail in #4 below. (MthouØi
InstItutIonal controls were always a
component oldie remedy , the addhiuual
iistllullunal controli for the cu ion
areas are a new component In ihe
proposed remedy.j
• flecause childrrns ex sure to lead is a
mnpr concern at the site,a geu-texale liner
covered with I toot of clean soil will be
iet 1 uired for all existing and an3 new play
areat at Centennial and Utinter Cieek
Contio ,n,n ,unii A vegetative cc ”. er will I ,
tequired to complete the protective battier
iii the pla areas In place of the veaetJtI%e
cover. I foot of clean sand Over the
gro-textile liner and tie 1-fuot soil cover
may be substituted in these pla zuens
These requiremenu will provide an e tia
level of ptotecuoru in areas nere child, en
ma play for extended periods of nine
(Thi, component of the rvniedy luig
cliaii ed from the 1989 reuieiiv which
required a 2-fool soil cover. Alto. the
19*9 remedy did not provide for
cover as a uhmtlInse for a vegetative
cover to complete the rernedy.j
Institutional Controls
The term institutional controls refers to
administrative requirements adoptetfl by
governing bodies to require or prohibit certain
t)pesof activities. Under the rn’posed remed’..
institutional controls will be adoined Cu ensure
the effectiveness and permanence f the
remedy. Institutional contrt ’ls include (‘uuiiny
or City ordinances, condominium association
covenants, b -laws. or rules and reguiauvns
• A mepor comçwrnent of the pmposed remed’. t
the adoption of institutional ct’ntiuls that wilt
ensure the effecti veness and perniaitence ol the
remedy. The purpose of the instiiuitio ,ml
controls is to ensure that any future
development or other activity within the
boundaries of the site doernot interfere with the
integrity and effectiveness of the permunetit
remedy. Elnattluslonal controls have alwavu
been a conipomienl u I She previously selected
remedies although they have never bee ”
defined in detail as they have been in this
ESD.J
• The institutional controls will apply to all
properties within the site buundary ias shown
on Exhibit h. whether or nun the pruperlies ure
remcdiaied during the cleanup.
• Institutional controls will include varn iis
measures to maintain the integnt ut the iou
and vegmtativecover. instiwt,wialcon,rnli ma’.
also include notices to future owners on the site
4.
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a . i
1 .
advising them of the need to maintain the
vegetative cover on the r property
• The jw iiitai’. measute will be the enactmentand
enf rienieifl of C ,unts ordinances that will
ieqtilie permits fur some ts pes of activities and
t . ,i,, ‘lu,iiu.e with the emeth for otheracti vuties.
I he ei fornianve standards in the Counc ‘s
.r.i 1 ’ sed o,dinances are based on the
ietlli lrements of the remedy as described in the
1 (01) und in this ESD.
• The County ordinances will include additional
requirements for the Hunter Creek and
Centennial Condominiums due to the
difference in the required thickness of the soil
cover. Other measures may include existing
regulations and restrictive covenants enforced
by the Hunter Creek and Centennial
Cunduininiuni associations.
• The County ordinances are betng drafted by the
Cuu,nt with input from EPA. the State of
Colorado. and local elected officials. Residents
of Aspen and Pitkin County will have an
to provide input on the ordinances
dunng the Cotinti adoption process . A draft of
flit proposed ordinances will be published in
iiiuil-March IQQO,as part of theCounty’s tormal
adoption process.
• A draft of the County ordinances will be
atutdte J to the final ESD. When the ordinances
are adopted. a cops of the adopted ordinances
will replace the draft and beatteched to the final
ESD. If the ordinances are not adopted by the
County as presented in the drsft tT hed to the
flnal ESD. then EPA will reevaluate the
proposed remedy.
• The County ordinances under development ate
described in general terms es follows:
• Permits will be requited for activities or
developments that will involve excavation
of more than I cubic yard of soil. For
activities that involve no excavation or
excavation ol less than 1 cubic yard of
soil, the property owner will not need a
prrmit. but will haveto comply with certain
requirements or peifotinince standards.
• Information regarding the pri’p *e ’J
activity or development such as the Je ih
of excavation, the vnlume of inatet i.il to ut
e cavared. the duration of the rrn,ect. eec.
will be requited forapplucauuui ufJ ieimi
• The performance stand.irds or
requirements for maiunainiiig and iestortng
the renied are bitefly summaiizeti bchuw
• Flowers and vegetables will he rlanted
only in raised bed gardens at least (
inches a ve the soil cover lut •t toi.tl
of 1$ inches of clean soul .iL,uve
cont.arntnaied soils
• Where excavation of the iou cover is
necessary for landscaping purpoies
trees and shrubs. the property owner
must comply with the perforniance
standards discussed below Excavation
for landscaping will be limited to !ps
than a (out where possible.
• For excavation and constiuction
activities, interim safety measures will
be required in minimize d i t, to
prevent surface runoff and erosion, and
to prevent access to conianuiiiated
materials throughout the duration of
the project.
• The Direetnr ii? the Mpen.Pif kin
Environmental Health Department will
determine through the permitting
process the appropriate method fur
disposal of coneatninated sot l .’1ai lings
displaced due to development
activities. Disposal of displaced
contaminated soils/tailings will be
eidser I) on the property covered b.
the approved remedy or 2 in the
on-site repusitury. The Duiei.tui
requite soil sampling to determine the
lead cuntent of such materials.
• Containment of contaminated
soilMailinp on the prupeity will be
encouraged to the maximum extent
possible by minimizing their
displacement in the project design or
by incorporating the material into the
existing topography and coveting with
44
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I I
vi:._ .L....
the appropriate components of the
remedy
After completion of any act lvlvv or
debek’pmellt, the propert owner will
be retuired to ieplace or restote the
permanent remedy, I e. geo-cextile
Imimer co’.emed by I foot of clean topsoil.
and a vegetative cover to rnininiize
eros ion.
Because the remedy is diffeient for the
Hunter Cieek and Centennial
Condonii iiium complexes. additional
requirenients will be included in the
Counr s ordinances. These additional
requirements are sunrniarized as follows:
• Lawns or other landsca ’ed areas may
be fenced, as determined to be
necessar by the Cownv. to prevent
deterioration of the vegetative cover by
foo traffic from residents. Such areas
would be fenced with wood or other
effective fencing materials at a height
of 3-1,2 feet. Any fencing would be
appro’ted by the County prior to
installation.
• Lawns and other landscaped areas will
be posted it, notify reardenu of the
restricted use of such areas. The
purpose of the signs would be to
remind residents to keep to the
designated walkways.
• Vegetated and paved areas will be
regularly maintained. Any changes in
the use of the v .etat4 or paved areas
will require prior ap uvai frum the
County.
• The Cnndomimum Associations will
be responsible for maintaining the
common ar and will be required to
submit an annual budget and
maintenance plan to die County fat
approval.
• The Condominium Associations will
also be required to pasta bond with the
County to guarantee annual
maintenance costs. The County may
draw on the bond should rI,
Condominium A3soci tiu’ns fail t
meet their maintenance uWigatiuiis
• The County will conduct monthi’.
Inspections of the conimtm ness I he
cost of these inspections will be borne
by the Condommiuni Auoci4tionS
• Restrictive covenants will be placed on
the properties governing the use arid
maintenance of playiiig fields and
recreational areas.
• No new playing flelds or recreaiiuii:il
areas will be constructed withcjtit
County approval.
The implementation and enforcement n( the
institutional controls by the Counr is a nia’.’r
component of the remedy As such. if the
institutional controls as envisioned in
document are not adopted by the Count’.. then
EPA would need to reevaluate the proposed
remedy once again.
Protictlv.n.ss of th• Rimidy
The remedy proposed in this ESI) is proreciive ‘f
human health and the environ menc because it 1,resks
the exposure pathway between the containi nated
soilMailings and the residents living tin-site The
gea-cextilehineranda I-foot soil cover pn’posetl in
the remedy provide a protective barrier that
preventa direct contact with cumannnuted soils
Paved driving areas, etc., and permanent
structures also provide a protective barrier against
direct contact.
The gee-textile liner prevents mi ring of underl’. i ng
contaminated materials during the plau.etiieiii of the
soil cover and due to frost heave and other natuial
forces after cleanup. The liner also alerts a pmopei
owner of the need for a permit under (..uunty
ordinances.
A maintained vegetanve cover ensures that the soil
cover remains intact and does not erode. :nd expose
the underlying contaminated soils. A vegetative
cover also minimizes dust, protecting the overall air
quality.
12
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0222413
The County ordinances and condomiiiium
i estr,ctwns provide institutional measures that
ensure the ifltegrit of the engineering crintrols r i
tli eme J Because contaminated so, Is will remain
ufl-Site nsttt etiunal controls are necessai to
enswe the permanence of the soil cover
The Counr r tdin rKeS allow for some disturbnnce
of the soil cove,, but the institutional controls will
ensure that the remeth is restored or replaced upon
cuiiiple,iun of the ticti vit Provisions for an ‘ i ‘pen
ie7’OSiti;rV ensure tin appropriate disposal place for
ct .iitnininnted niutenals.
The (‘ountv ordinances include additional
retluiremenis governing the use and maintenance of
the landsc petl areas at the Hunter Creek and
Cententinal Condominiums. The County ordinances
also require fiiiuncial assurances from the Hunter
Creek and Centennial Condominiums to ensure
proper maintenance of the grounds.
The County has comnntted to implementation and
enforcement of the ordinances descnbed in this
ESD Enforcement of the institutional controls is
a iiretJ by the County entering into a Consent
Decree with EPA.
Additionil institutional controls will ensure the
niainternuiice of the vegetative cover. Restrictive
cuveirnilta currently exist at the Hunter Creek and
Centeniutal Condominiums which govern the use of
the landscaped areas. Notices will advise ill future
owilers on the site of the need to maintain the
vegetative cover on their properly .
Although the 989 remedy requuing .2-foot soil
cover anticipated institutional controls as a
coniponent of the remedy , the b 1 lth and scope of
the institutional conuuls werenaeucomprebensive
as those proposed here. Underthe (919 remedy with
a 2-foot soil cover, most “homeowner’ st.’tivities,
i.e.. gardening and other yard improvements, would
nut have involved excavation below the top 2 feet,
thus minimizing the permitting requirements under
the Count> ordinances. With the proposed remedy
iequiring e I-foot suil cover, permits under the
Counts ’s ordinances may be required in more
inutinces. A prntectlve barrier against direct contact
with cunuiniinated soils would be provided with
eithern I-or 2-foot soil cover,as longaseither is
iiwiniained apprupnately.
The 086 remeciv,as modified b the I 89 remetI .
and the proposed 1990 reme h ieniain
fundamentally the same. The same waste
management practices will be emplo eti Both
remedies have combined the practice of isol iiiiig
the contaminated with instimuii n I .‘miols
to protect human health and the environment The
other elements of the 1986 remedy iemuin in the
proposed remedy.
The major differences between the (986 revnedi..
which was subsequently modified b> the I ‘189 ESD.
and the proposed 1990 remedy are as follows
• The proposed remedy requires a gec-textile
liner covered with I foot of clean sail at i a
vegetative cover. The previous reniedy as
modified by the 989 ESD required 2 feet of
clean soil and a vegetative cover Both remedies
are considered protective since I””” rwvide a
Pt oteu.’ttve bather to pre’ent direu. - .tii t with
contaminated soils. However, a I -foot .over
will likely require more intervention (mm the
County through its permitting progiurn to
ensure that the shallow cover is niaintauneti
• Thepvoposedremedvwiflrequiresc ’iltampiing
on each property to demonstrate containti lauivn
within the top I foot before soil removal arid
placement of. gea-textile liner covered with I
foocof clean topsoil and a vegetative cover rhe
previous remedy did not require sampling of
each properly prior to soil remediuu;un By
sampling each property before remediatii,n.
EPA will be able to more .,.‘curateI detei iniiue
the required p. ’ty for the un-site repository
• Changingthesoilcoveirequirement from 2 feet
to I foot will minimize the need for a second
on-site repository at the Smuggler Racquet
Club. Should a second repository be necessars,
the scale of the fepvstcory at the Racquet L tub
will be much sn*LIer.
• Soil sampling will indicate only whether
contamination was found in the soil sanil’ies
EXPLANATION OF
SiGNIFICANT DIFFERENCES
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0222414
taken in the trip 2 inches Previous soil
,sampling restilts have indicated crirnamirmtp
ari exist 1,ekiw the top 12 uwl,es Situ.e the
‘. .i fl( i3l f’r contannhlation CX IStS below the op
I . u ,il I pi Qp. htie3• all rroperhlel will be
ietpi.ir d ti Irnve the rnn or componetn of the
renieth. e. i vegetative cover and paved
Jitviiig ,iien.s All ptuperty OWners Will also be
required to nulintain the equivalent of the
emeth and compl with the tnscitutjuiial
c ntrt’ls whether or not the property is
emedmted
A major difference between the 10S6 remedy
s modified by the 989 ESD is the thickness
of ihe soil cover required for the Hunter Creek
and Centennial Condomimums. Because of the
difference in uses of the property and the
“aintenance of the property by the
oiidiiiii,n,um assoc ions , the prnposedd
ietiietjs will consist of 6 inches of clean soil, a
vegeltsiive cover and additional institutional
-l’iItio45 that will be enfor - d by the Coumy.
ilic l’ 8Q remedy required 2 feet of clean
L ’w.klill and topsoil and. vegetative cover.
Itisiltutional controls area major component in
k’ih the pruposed remedy and in the remedy in
(lie 1989 ESD. However, as discussed above
under the Protecuveneas of the Remedy ’, the
institutional controls envisioned in this remedy
will be more comprehensive. Additional
institutional controls will be required fOr the
HuncerCreek and Cemennle1Conju,,
ensure maintenance of the dit Ip,d atese.
• The destgn enteria (e.g., cap me sl, erosional
stability. etc.) of the on-site re, .itonrq leai will
- not signilkantly change from the 19*9 remedy .
However, the scale of the second un-site
repository, if needed, will be much smaller.
• Institutional cdntrols wijj become a more
iiiegral pert of the proposed remedy than was
etivisioned in the previous remedy. The
Count ’s role in the implementation and
enforcement olthe institutional controls will be
trucial to preserving the integrity of the
proposed remedy. The County’s enay into a
Coitsent Decree with EPA ensures that the
tiistiiuti. .,nal controls will be enforced.
/ ‘
7
The monitoring reqt ,Iremen,3 outlined in ri
ROD for ground water qualics ‘rid ti v
mjlntenance of ihie soil over will be
to reflect the rhanges to the remer.h as preset,ce.j
in this ESD
SUPPORTING AGENCY
COMMENTS
The Colorado Department of Health h s reviewed
the proposed 1990 reniedv in ‘his ESD and has
provided commenu to EPA. These coillinents have
been iricorporateti into this CSD to the n ’axI, ,,ti,i,
extent practicable. The Colorado Deportment L’f
Health Concurs with EPA in the proposed
modifications to the remedy
The changes to the remedy were ninIe in
accordance with all applicable and statt,tur
requiremenu for hazardous substances rem ii rung
on site. Because hazardous substances above
recom,y,enñ levels will remain at the site. r i icdi
review (every 5 yeats of the response action will
be conducted, pursuant to CERCLA. to ensure that
the remedy remains protective of human health and
the environment.
The proposed remedy meets the statutory and
regulatory evaluation crnena for selection of a
remedy. Because treatment of the principal threats
at the site was determined to not be prai.ii al. this
reniedv does not satisfy the statutory preference fur
treatment a pinciple element of the i enietly
However, the revised remedy utilizes permanent
solutiuns and alternative treatment technologies to
the maximum extent practicable for this site.
Considering new and existing iniorniatmomi and the
changes to the selected remedy, EPA has
determined that the remedy remains lwu lective ut
human health and the environment because ii breaks
L
STATUTORY
D TERMINAT1ONS
‘4
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0222415
the exposure pathwa b pteventing direct contact
with cutitantinated suilsitailings
Th renieti’, complies with the recommended he2lth
atI .ist ,,’. b the Agency fur Toxic Substances and
Oiiease Registry for cleanup of soils Contaminated
with lend The remedy requires remediation, where
lead cc ncentrntiuns are greater than I 000 ppm in the
top I foul of soil on the site.
As noted iihove. conmminated materials will remain
on-site after completion of the remedy The
kmg-tenn effectiveness of the rented is ensured by
the engineering coin patients of the remedy and the
ongoing maintenance of the vegetative cover
i equited b the mnstitutiunal convuls.
D inng imnplementneion of the remedy, dust levels
may increase slightly. Stringent health and safety
measures will be implemented to minimize dust
levels and ensure the safety of both the workers and
the resident,, thus ensun ng short-term effectiveness
of the remedy.
linplementabiliry of the remedy should ‘i ”t he
l’r blem because the technology i i
engineering practice for preventing dute .t curii .t
with coittaiiiii ted soils.
The cost of the proposed remedy is estimated Ii
between $4 5 million to $5 0 million This is less
than the previous cost estimates for 986 anci 9R’I
remedies, due in large part to the reductit ,, in the
soil cover frumn 2 feet to I loot, and he pvteiii.iul by
not needing a second repository
EPA has worked extensively with the c ,iiinluini’.
during the pest year to understand the residents
concerns regarding the remeds To the e ient
practj bIe, EPA baa addressed the cunh,nu ,,,,y s
concerns. Because the changes tu the reniedy
presented in the 1989 ESD ra, ed fltimCi ,,yi
concerns,EPA isprovidingthis F.St)rndran It ” the
community to review and provide comments be lure
a final ESD is issued. EPA will attempt to ad4iess
the community’s comment, regarding this draft
—
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—
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-
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15
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A ‘S
to
ESP to the extent pos uhIe The State rif Colorado
surports the proposed changes CO the remedy
SCHEDULE FOR SAMPLING
AND CLEANUP
TIie schedule for the Smuggler Mountain site soil
sampling and cleanup is presented below in Exhibit
4 The relocation of the ptpeline isscheduled forthe
f&iI I of 1Q90 and the cleanup in the residential areas
will begin in the Sprrngof 1991.
PUBUC PARdT1CIPAT1ON
Citizens ave invited to attend one of the scheduled
,sIoriirntii’isal meetings on the draft Explanation of
SigiiiIkant Differences to the remedy to be held the
week of March 19,1990. in Aspen.The Community
k invited to submit written commertu on the draft
l!SD to EPA. Comments should be sent to EPA ax
the address given below by Friday, March 30.1990.
Questions regard ing the Explanation of Significant
Differences should be directed to:
Paula M Schmittdiel
Remedial Project Manager
Phone 0: 303) 293-1527
available for public review at the following
locations:
Pilkin County Library
IZUE Main Street
Aspen, Colorado 81611
303-925-7124
Hours. M.Th, lOam.9prn. F-Sat.
IOam-6pni. Sun. l2prn-ópm
Aspen-Pitkan County Environmental
Health Department
30 S. Galena Street
Aspen. Colorado 81611
303-920-5070
Hours: M-P, Sam-$ptn
EPA Superfund Document Control R wtt
999 18th Street. 5th Floor
Denver, Colorado 80202
303-293-1*07
Hours:M-F,*am-4pm
MNUNG UST ADDmoNS
if you did not receive this update b mail, and you
would like to be .iAded w EPA’s mailing list foi the
Smuggler MountainSite, please send the following
infonnation to:
Ms. Sony. Pennock
Office of External Aff airs i8OEM
U. S. Environmental Protection Agency
999 18th Street, Suite 500
Denver, Colorado 80202-2405
Sony. Peniwck
Community Rele ona CoonIii
- PhoneO(303)2N-1115
Toll-free Nu ber 1-100 .7594372 (in Colorado)
Written cnmmefga on the draft ESD should be
addressed to Paula M. Schmitrdlel at the address
given below:
U S. Environmental Protection Agency,
SHWM-SR
999 18th St.. Suite 500
Denver, CO. 80202-2405
The administrative record, which contains the
cunip4ete documentation for the site and additional
copies f the ROD and the 1989 and 1990 ESDs, is
I
C)
Addrans
at y st ase Zip
Company, organization, or governmental
entity
—
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16
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0222417
UMTED STATES ENVIRONMENTAL PROTECflON AGENCY
REGION VU
999 ISthSTREET -$UTE 500
DENVER, COLORADO 80202-2405
R•f: SOEA
MEEr:Nc ANNOUNCEMENT
To: Property Owners and Residents
Smuggler Mountain Superfund Site
From: Sonya Pennock, Commun .ty Involvement Coordinator
Re: Community Meetings on Proposed Explanation of
Sign .iicant Differences, March 19—22, 1990
The U.S. Environmental Protection Agency (EPA) will begin a
public comment period on a draft Explanation of Significant
Difference. (ESD) modifying the cleanup plan for the Smuggler
Mountain Superfund Sit. Friday, March 9, 1990. The public
comment period will end Friday, Ma.rch 30, 1990.
A seri s of meetings have be.n scheduled to provide you with
information on the ESO. This information will help you decide
whether you wish to submit written comments on the proposed
change. to the cleanup plan. 8ecaub. m.eting space is l rn .ted,
EPA encourages you to attend the meeting designated for the area
in which you live; If you wish to meet individually with EPA
dur .ng this time, plea.. call Carolyn Hunks, SRM, 920-4408. For
more information on procedures for public co.nt, please call ne
at the EPA toll—ire. number 1-800-759—4372 or at my office number
(303) 294—1115 or Diane Sanelli, Community Involvement
Coordinator, (303) 294—1139.
MEETING SCHEDULE
March 19:
-7:00 PM - Smuggler Landowner Task Force & County
Co tssioners
March 20:
11:30 AM — Smuggler Racquet Club
5:30 PM — Site—wide, Pitkin County Library
120 E. Main St.
8:00 PM — Centennial Condominiums
Community Center - Old Dining Room
March 21:
1:30 PM — Site—wide, Pitkin County Library
120 E. Main St.
6:30 PM - Smuggler Mobil. Home Court
Smuggler Mobile Home Owners Assn. Office
Mareh 22:
6:00 PM — Hunter Creek Condominiums
community Center - Large Dining Room
•1
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Smuggler Mountain Mining Waste NPL Site Summary Report
Reference 4
Excerpts From Soil Clean-up of Smuggler Mountain Site,
Aspen-Pitkin County, Colorado, Explanation of Significant Differences;
EPA Region VIII; May 16, 1990
I
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O2O22 6
EPA
Region VIII
Superfund Program
SOIL CLEANUP OF __
SMUGGLER MOUNTAIN SITE
EXPLANATION OF SIGNIFIC T
DIFFERENCE S
MARCH 1989
ADMiNISTRATIVE RECORO
- 7 9FMLIE P4 UMBER
INTRODUCTION I
The purpose of this document is to explain the significant dif-
ferences between the Record of Decision (ROD) signed by the
TJ. . Environmental Protection Agency (EPA) in 1986 and the
remedy which will be implemented at the site. Under Section
117 of the Comprehensive Environmental Response. Com-
pensation, and Liability Act of 1980 (CERCLA), as amended
by the Superfund Amendments and Reauthor i uon Act of
1986 (SARA), EPA is required to publish an explanation of
significant differences. This document provides a brief back-
ground of the site, describes the remedial action to be under.
taken and explains the ways in which this remedial action dif-
fers from the remedy selected by EPA in 1986.
This Fact Sheet will, by necessity, present only a synopsis of
information on the site. Theadmuusirauve record, which con-
tains the complete documentation, is available for public re-
view at the Pitkzn County Library and the Aspen-Pukin
County Environmental Health Department in Aspen. Colo-
rado. An additional copy of the administrative record iS 10-
cated at the EPA Region VII I Library in Denver, Colorado.
SITE
HISTORY
AND
BACKGROUND
The Smuggler Mountain Site is located in Aspen. Pithn
County, Colorado. The old Smuggler mine workings are to-
cated at the base of the western side of Smuggler Mountain.
Waste rock, tailings and slag cover much of the site. The mine
wastes are either exposed, covered, or, in many instances,
mixed with native or imported soil. Due to its pro mny to the
resort city of Aspen. development has taken place iminedi-
ately on top qf the waste piles. or e piles have been leveled
$1
or moved to the edge of developed areas, where they remain as
berms of contaminated sod.
The site is approiarnately 90 percent developed. Development
consists primarily of residential properties including two large
condominium complexes. two mobile home par 9 . several
small condominium developments (4—12 unIts). approxi.
mately 25—30 individual homes and a tennis club.
Soil analyses in the early l980sby EPA and the potentially re-
sponsible parties (PRPs), identified concentrations of lead up
to 46.000 parts per million (ppm). Elevated levels ofcadmiurn.
as well as other metals. were also found in the sods. A poten-
tial ground water problem was also identified. The site was
proposed, for the National Priority List (NPL)ui October 1984.
The primary concern at the site is the potential for humans to
be exposed to lead and cadmium through direct contact by in-
halation or ingestion with mine wastes and contaminated soils.
1;
vIEErING
, r- —-- —,
the ptdeanup
dmembersofthe tyiara.
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1
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02022:
BACKGROUND ON LEAD AND
I CADMIUM CONTAMiNATION
I SUMM j y OF THE 1986
RECORD OF DECISION (ROD)
Lead is a heavy metal which is present in the environment
from various sources. Lead can be absorbed by humans either
through inhalation or ingestion. Because smalL children tend
to put things in their mouths. they are more at risk to lead ex-
posure than adults. if they live near a source of lead pollution.
Lead toxicity affects red blood cells, the nervous system and
the kidneys. Lead may also affect human reproduction and has
been shown to be carcinogenic in animal studies. Even at very
low levels, lead exposure can cause harmful effects to the
nervous system in children.
Cadmium is a heavy metal that is also frequently associated
with mine wastes, as is the case at the Smuggler Mountain site.
Studies have shown that cadmium may be carcinogenic to hu-
mans, has chronic effects on the kidneys and may affect human
reproduction. Plants, including leafy green vegetables and
root crops are subject to uptake of cadmium from contami-
nated soils. Vegetables grown in such soils may present an ex-
posure to humans through the ingestion of those vegetables.
• The objectives of the 1986 ROD were to isolate waste rnater i-
als with lead concentrations greater than 1000 ppm. to con-
tinue monitoring the groundwater, to provide an alternate
water supply for residences with domestic wells, and to con-
duct operation and maintenance of the remedy.
The ROD also divided the site into two operable units (OL’):
OU 1— Residenzga areas including the site of the repository 3t
the MoUie Gibson Park and OTJ 2- Smuggler Mine site. This
Explanation of Significant Differences will only address
changes to the remedy selected for the residential area (i.e..
OU1)
The remedy selected in 1986 consisted of the following ele-
ments:
• All soils/tailings with Lead concentrations greater than 5000
ppm were to be excavated and placed in an on-site repository
under the ownership of Pitkin County. The Motha Gibson
Park. Located on Smuggler Mountain below the Smuggler
Mine. was proposed as a suitable site for an on—site repository.
AERIAL VIEW OF THE SMUGGLER MOUNTAIN sm
2
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Smuggler Mountain Mining Waste NPL Site Summary Report
Reference S
Excerpts From Focused Feasibility Study for Ground-water Remediation,
Smuggler Site, Aspen, Colorado; Fred C. Hart Associate, Inc.;
July 5, 1985
4
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FOCUSED FEASIBILITY STUDY
FOR GROUNDWATER REMEDIATION
Seuqgl.r Site
Aspen, Colorado
Prepared by:
Fred C. Hart Associats, Inc.
a . a.. S
u riiui svvusuv
New York, New York 10036
July 5, 1985
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1.0 Executive Sun nary
The Smuggler site is an old silver—lead mine area which is located
approximatel , one mile northeast of the city of Aspen. Mine tailings pro-
duced durir. the peak minirTg years 1879 to 1920 are piled outside of the
mine shafts. Over the course of the years, the tailings have been moved,
used for fill material, or have been mixed with nan—made materials.
The exact extent of the site area is not yet defined. A study is
currently planned to define these limits. Several tunnels and shafts exit
Smuggler Mountain within the site area, namely the Cowenhoven Tunnel, Smug-
gler Shaft and the Mollie Gibson Shaft.
The site is topographically located on the northeast slope of the
Roaring Fork River Valley. Coarse—grained unconsolidated glacial outwash,
poorly sorted glacial noralnal deposits, and alluvial fan deposits imme’ i-
ately underly the mine tailings. The bedrock underlying the unconsolidated
materials Is the Belden Formation. This formation is composed of limestone,
dolomite, slate and evaporites. The are body which was mined is a zone of
mineral enrichment located along a thrust fault which follows the contact of
the Leadville Formation and the unconformably overlying Belden Formation.
A number of investigations have been undertaken at this site. The
Ecolo ’ and Environment, Inc. (E & E) Field Investigation Team performed a
sampling investigation at the site in 1983. The Investigation was the
result of a request by P itkin County to characterize any human or environ-
mental threat posed by abandoned mine tailings in the northeast quadrant of
Aspen, Colorado. The county became concerned following the analyses of soil
and plant samples taken from the Aspen area which indicated elevated levels
of trace metals, specifically lead and cadmium (Boon, 1982). An initial
report or t,rie results or tne E & E sampling was crafted in response to a
Technical Directive from the Environmental Protection Agency (EPA) and was
distributed in March 1984 (E & E, 1984a).
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1-2
During this time, EPA requested Camp, Dresser & McKee, Inc. (CDM), to
prepare a Draft Work Plan for the Remedial Irivestlgatlon/FeaSibilftY Study
of the site. EPA is currently reviewing all subaittals to determine whether
the site .sho.urabe formally listed or removed from NPI. consideration.
Currently, the RI/FS work plan proposed to EPA by CDM notes that the
short term risks posed by the site are primarily due to the uncontrolled
tailings. Direct contact with dusts may lead to dermal ingestion, arid
potentially contaminated wind blown dusts could lead to ingestion through
inhalation. Surface water transport of heavy metals originating from the.
site could also be responsible for contaminant dispersion.
The currently planned Field Study proposes to provide data to help
mitigate these risks. All areas of tailings, mixed tailings and fill mate-
rial, and contaminated soils which exceed toxic action levels will need to
be covered, and surface drainage controls such as culverts, toe drains,
settling basins will need to be implemented to mitigate the problem of
dispersion of contaminants by surface water.
Chapter 3 indicated the need for implementation of remedial actions f r
the proection of the public health. This Feasibility Study was prepared ir
response to those needs with respect to groundwater. The Feasibility Study
evaluated alternative technologies and alternatives that could be imple-
mented at the Smuggler site for mitigation and/or elimination of potential
endangerment mechanisms.
- F4ve categories of resediai actions were evaluated for implementation
at the site, includ ing monitoring, source removal, source isolation, 2 ume
capture and water supply replacement. Sixteen remedial technologies w re
initially evaluated for applicability to the Smuggler site. Nine technolo-
gies were found to be applicable and combined into twelve remedial actions.
These twelve remedial actions were initially screned based on an evaluation
of their evironaental effects, environmental protection, and iinplementaci 1-
ity/reliabilttY. Nine alternatives survived the initial screening process
and were subjected to detailed evaluation.
1
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Nine criteria were used to perform a detailed evaluation of each alter-
native. These criteria included: reliability, i,nplementability, technical
effectiveness, environmental concerns, safety, operation and maintenance,
costs, regul ry requirements, and public acceptance. Using these cri-
teria, it was possible to assess and identify the most appropriate alterna-
tive for the Smuggler site.
Based on the detailed evaluation of the nine alternatives, a combina-
tion of alternatives 3, 5, and 9 appears to be the proper the lowest cost
alternative that is technologically feasible and reliable; and which efrec—
tively mitigates risks pàsed by the Smuggler site.
Additional studjes may be required for the analyses of slope stability,
leachability (acid/base potential) and permeability in order to determie the
need for surface sealing (alternative 4) and/or subsurface drains (alter-
native 8). These studies could be performed during the currently p’an ed
field studies.
‘1’
Ilk
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2.0 BACKGROUND INFORMATI N
This chapter of the Focused Feasibility Study for groundwater remedia-
tion at the Smuggler Site presents a brief overview of background inforTna-
tion. Sect-ion 2.1 discusses site background information including t e
location of the site, waste disposal practices at the site, and site geolo y
and hydrology. Section 2.2 briefly discusses the nature and extent of
contamination problems at the site. SectIon 2.3 discusses previous resp ise
actions and investigations at the site. For additional detailed background
i,iformation concerning the site, the reader is referred to t e following
documents:
a. Lincoln DeVon, Inc. 1983. “Interim Report on the Surface Geology
and Mine Study, Centennial Project, Aspen, Colorad&’ Prepared for
Centennial Partners Ltd.
b. Ecology and Environment, Inc. 19844. “Interpretive Report and
Health Risk Assessment of the Smuggler Mine, Aspen, Colorado”.
c. Caap, Dresser, and Mckee Inc. 1985. uDraft Work Plan for Smuggler
Mountain RI/FS, Pitkin County, Colorado.” U.S. Environmental
Protection Agency Region VIII, Denver, Colorado.
2.1 Site Description
2.1.1 Location . The site is located imaediately northwest of the City of
Aspen i Pitkin County_ The tailings area Fs situated In the nortnwes .c.r1y
trending valley of the Roaring Fork River at the base of Smuggler Mountain.
A location map Is presented in Figure 2-1.
A .‘ — Af. ..I •_ j•• _ A ’ ——
d I ul QU I rtal.l.i e . use eses eti uu aa e e lsuAIusGbC’J
acres of developed and undeveloped properties. Tailings from the Smuggler,
Mollie Gibson, and Free Silver Mines, the Cowenhoven Tunnel, and from past
smelting and milling operations related to these mines and tunnels, have
been deposited in the area. In most places, tailings have been mixed with
other materials. However, some tailings used as fill have remained un-
covered (E&E l984a). It is e imated that undisturbed mine tailings make up
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SMUGGLER MINE SITE
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approximately 25 percent of the 75 acre area while undisturbed soils :n,—
prise another 25 percent (E&E 1984a). The remaining 50 percent is primarily
a complex mixture of mine and mill tailings, native soil, and fill.
The deposited tailing material was a result of the mining and milling
of silver, lead, and zinc. Quantities of the tailing ma’erials have been
established at approximately 2.4 x i0 cubic yards CE&E 1984b). The distri-
bution of the tailings, as well as their reworking since their original
distribution, is not well-defined. Past records indicate that tailings on
the Smuggler site were placed there from 1880 to 1915. The tailings piles
from the Cowenhoven Tunnel were leveled and sc .tere i when the Hunter Creek
condominiums were built. Recent investigations indicate that some of the
tailing piles were leveled, and tailings were scattered over the present
sites of the Smuggler Trailer Court, Smuggler Racquet Club, Hunter Creek
Condominiums, and the Centenitial—Aspen Condominiums (McIntosh 1985). There
is currently an active permitted mining operation with tailing piles upslape
of the-sits which, due to permitting, is not considered as part of the site.
2.1.3 Topography . Topographically, the overall site slopes moderately
toward the west and southwest, with an overall gradient on the order of
approximately 10 to 15 percent. However, at isolated locations throughout
the site and along the southeastern boundary, gradients on the order of 100%
occur. The ground surface elevation ranges from approximately 7936 to 8164
feet above mean sea level. -
Throughout the years, parts of the ground surface at the site have been
altered as a result of mining and earthmoving acti Itles. Characteristics
of the sit. include numerous small closed depressions. Several of these
areas of interior drainage are located above abandoned min, shafts, tunnels,
anø stopes cavernous lined—out areas). some of tnese closed aepressions
are the result of ground 3ub:id nc;, particularly over thc old t c C ::r
Mine shaft, the Fr e Silver Mine shaft and Cowenhoven Tunnel. A depression
approximately 12 . 15 feet deep is evident at the Free Silver shaft. As
mentioned, the topography on the site has changed due to miscellaneous
grading (both cutting and filling) through the years. On more than one
occasion, it appears that portions of the site have been either borrowed
from, filled on, or disturbed by grading.
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2.1.4 Hydrogeology . Generally, the groundwater system underlying Smuggler
Mountain is dominated by extensive honeycombed mine workings. These work-
ings serve ac conduits transporting groundwater from within the mountain to
the level of ..the Roaring Fork River. Groundwater levels are affected only
slightly bythe stage of the river, moderately by the amount of rainfall dnd
snow nelt runoff available on the mountain, and gre t1y by the efficiency of
the drainage network formed by the nines. Cave-ins and other blockages in
the old workings may impede drainage, generating large rises in water
levels. Conversely, “b1ow—outs ’ of blocked tunnels resulting from hign
water pressure can produce large water discharges .at the ground surface,
with consequent falls in groundwater levels. Variations in pore water
pressures caused by changes in the grounawater regime may have a significant
effect on the overall stability and subsidence potential of the shallow mine
workings.
The sit, is underlain by various surficial deposits wnich include
alluvial deposits, and glacial moraine and glacial outwash deposits. These
deposits are characteristic of valley fill deposits. It is reported that
the valley fill deposits are several hundred feet thick in the Roaring Fork
River Valley. Depending on their extent and thickness, as well as perme-
ability, these deposits will yield anywhere from 5 to 1000 gallons of water
per minute. However, it should be noted that the investigation performed by
Ecolo and Environment, Inc. in•March 1984 indicated there was no alluvial
groundwater system underneath the tailings at the site.
Underlying the aforementioned surficial deposits, the bedrock is divid-
ed into the Gothic Shale, Belden Shale, and Leadville Limestone Format.io.r s.
The Leadville aquifer, which may be up to 200 feet in thickness, has been
reported to yield as much as several thousand gallons of water per minute.
The occurrence of water is a characteristic of fractures and solution con-
duits found In the aquifer.
2.1.5 Hydrology . The Roaring Fork River passes the site at a distance of
approximately 1000 feet to the southwest. In this reach, the river eleva-
tion is about 7870 to 7920 feet above mean sea level. There are no major
çô 1
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natural drainage channels crossing the site. However, site drathage is
affected by two small to moderate-sized basins located to the east and
northeast. Hunter Creek passes approximately 500 feet north of the site.
The Salvation Ditch, an irrigation canal, crosses the southern part of the
site at an elevation of approximately 8000 feet.
Any drainage from the site occurs largely as unconcentrated overland
flow, although channelization is apparent from mine discharge water. Speci-
fically, drainages from the Mollie Gibson Mine shaft and’ Cowenhoven Mine
access tunnel traverse the site. Each discharge is in the range of 1 cubic
foot per second (cfs) or less. Existing water quality data from eacr
channel show the discharge to be moderately laden with dissolved consti-
tuents, Including iron, manganese, and zinc. Based on samples collected it,
1983, total dissolved solids (TDS) concentrations range from 540 mg/i for
th Mollie Gibson discharge to 918 mg/i for the Cowenhoven Tunnel. The
Mclii. Gibson and Cowenhoven drainages discharge to the Roaring Fork Ri er
and Hunter Creek, respectively. Discharge in both streams is seasonally
variable. For the Roaring Fork River, low flows of 15—20 cfs occur during
the January through early March period, and high flows of typically 400 to
800 cfs occur during the mid-May through early July period. As for Hunter
Creek, flows generally range from 5 to over 400 cfs during similar periods.
2.2 Nature and Extent of Problems
As was previously described, the area under consideration encompasses
approximately 75 acres of developed and undeveloped properties. It is
estimated that 2.4 x 10 6 .cublc yards of mine tailings materials have been
generated at the sits (E&E 1984a).
Various studies have been conducted In the recent past to characterize
tne tailings arouna tn. muggier area (Boon 1982; LIncoln Devore, .L ; OOfl
1983; E&E 1984a; Clement 1985; McIntosh 1985). Results of these studies
show that several metals were detected in the soils and tailings. Con-
centrations of arsenic, barium, cadmium, copper, lead, manganese, mercury,
and zinc in the mine tailings and soil were elevated compared to a selected
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soil background sample (E&E 1984a-). The concentrations of these metals
the samples also exceeded the concentration of those el2ments found n
native soils throughout the United States (Clement 1985). These soil and
tailing areas and their constituents noted to date are described briefly
below.
2.2.1 Tailings . Si tailing samples were collected in September 1983 (E&E
1984a). Chemical analysis of these samples show elevated concentrations of
arsenic, barium, cadmium, copper, lead, manganese, mercury, and zinc. f
these metals, arsenic. ca’lmium, copper, mercury, lead, and zinc were report-
ed as being above background levels as described by Connor and Shacklet er
(1975).
2.2.2 Soils . Soil samples were collected downslope from the tailings piles
during September 1983, at an area underlain by graded tailings and covered
with transported topsoil (E&E 1984a). Chemical analysis of these samp es
indicated that, on the aver3ge. soil downslope of the tailings showed ele-
vated levels of arsenic, barium, cadmium, copper, lead, manganese, and zinc.
Results from other sampling events conducted by Boon (1983) and the
Aspen/Pitkin Environmental Health Department have shown some elevated metal
concentrations when compared to Connor and Shackletter (1975). Boon’s data
showed elevated levels of cadmium, copper, lead, and zinc. Three samples
were collected at the Smuggler Trailer Park by the Aspen/Pitkin Environ-
mental Health Department and analyzed for lead and cadmium (CDH 1982). The
average and maximum concentrations reported were 90 and 223 ug/g for cadmium
and 11,723 and 21,700 ug/g for lead. It Is uncertain whether these samples
were of soil or tailings (Clement 1985).
2.2.3 Toxicity of Contaminants . The site contains elevated concentrations
of arsenic, barium, copper, manganese, and mercury, and high concentrations
of cadmium, lead, silver, and zinc in tailings and contaminated soils.
Concentrations for these metals may exceed levls at which toxic effects
have been observed in plants, wildlife, domestic animals, and.man. EPA has
performed a risk assessment and has arbitrarily set action levels for soil
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cleanup. A study is planned to collect and analyze data to determine the
extent of surface remediation necessary at the site to mitigate risks posed
by the dermal ingestion or direct contact exposure routes.
Lead an Cadmium are the two metals of innst concern at the site because
of their concentrations and acute toxicities. Mean lead concentrations in
soil throughout the site area (4,060 uglg) and taflings (8,120 ug/g) exceed
the 1,000 uglg soil concentration In which significant lead exposure-related
toxicity has been reported for children. Children of the 1—5 age group are
at greatest risk because of their soil ingestion habits and greater sus-
ceptiblity to bluod lead poisoning. Studies in lead—contaminated environ-
ments show that children’s blood lead levels increase proportionately to
soil lead concentrations. When soil lead concentrations exceed 1,000 ug/g,
childrens’ blood lead concentrations exceed could 25 ug/dl, a level above
which toxic effects of lead poisoning have been observed in children.
(Blood lead levi s for children not exposed to lead are usually in the ra ge
of 12.7 ug/di or less. The primary effect of lead exposure is the inhibi-
tion of hemesynthesis i t t the biosynthesis of hemoglobin.)
It is Important to note that the blood lead studies conducted to estab-
lish the 1,000 ug/g soil lead concentration were based on atmospherically
deposited lead from automobile emissions and smelters. It is not known
whether exposure to lead in tailings and soil such as that at the Smuggler
site will produce elevated blood levels.
Cadmium is of concern for three reasons. First, Its reported concen-
trations in tailings a.na soils throughout the site area (means of 56 uglg
and 26 ug/g respectively). Second, various forms of cadmium are acutely
toxic. Third, cadmium compounds are generally more bioavailable than lead
compounds. Phytotoxic reactions to cadmium have been observed at soil con-
centrat.ions of 5—10 ug/g (background normally 0.1 to 1.0 ug/g). Feec con-
centrations of 1—5 ug/g have also resulted In cadmium toxicity. Increased
cadmium uptake normally results in increased tissue concentraTions, part cu-
larly in the liver and kidneys. As tissue levels increase, disfunctions of
thes. organs can occur. Cadmium is also of a concern at the site, one
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groundwater sample of 13 ugh exceeded the ambient water quality standard of
10 ugh. Elevated atmospheric cadmium concentrations were also observed.
Exposure to cadmium through water, dust, and direct contact could increase
concentrationr-to toxic levels.
Due to the rel tively neutral pH (6.38—7.22) of the tailings, soil and
bedrock materials, the metals on the site are in relati”ely insoluble forms.
The insolubility of the metals decreases their bioavailability and, there-
fore, toxicity. None of the metals are volatile, and, thus, they are
expected to persist for an extended period of time. Ev.idence suggests that
heavy metals in domestic wells downgradient of the site could be a problem.
It is unknown whether compounds detected in these wells to date could cause
a health related problem in these wells. These limnediate concerns lead to
an impending concern of further future impacts from the tailings to the
groundwater system. This Focused Feasibility Study acknowledges he
potential for future contamination of groundwater supplies, and therefore
looks specifically at alternatives to mitigate these problems. However, any
alternatives proposed for groundwater remediation in this Focused Feasibility
Study would al.so contain components of cleanup to address the other issues
of potential exposure from unstabilized surface wastes via the direct
contact or inhalation routes.
2.3 Previous Response Actions
A number of investigations have been undertaken at the site. Pitkin
County became concerned following analyses of soil and plant s’mples takø
from the area. Analyses Indicated elevated levels of trace metals, soecif i-
cally lead and ca 1u (Boon, 1982). The Ecolo ’ and Environment, Inc.
(E&E) Field Investigation Team performed a sampling investigation at the
site in 1983. The Investigation was conducted resulting from a request by
the county to characterize any human and environmental threats posed by
aDandoned mine tailings in the northeast quadrant of Aspen, Colorado. An
initial report of the results of the E&E sampling was drafted in response to
a Technical Directive from the Environmental Protection Agency (EPA) and
distributed in March 1984 (E&E, 19844).
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EPA requested Camp, Dresser & Mckee, Inc. (COM), to prepare a Draft
Work Plan for the Remedial Investigation/Feasibflity Study (RIFS) of the
site. The co’i ittee of Potentially Responsible Parties (PRPs) retained Fred
C. Hart Associates, Inc. (HART) to provide technical support to the
cot ittee. B ause gaps existed in the data base used for the ranking, EPA,
through its ;ubcontractor Ecolo c and Environment (E&E), performed a hydro-
geo1oglc assessment at the site to address the appropriateness of the
raiklng of the site. EPA is currently reviewing all submitt.als to determine
if the site should either be formally listed or removed from NPL considera—
ti n.
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3.0 CONTAMINATION ASSESSMENT
Determination of the nature and extent of remedial actions, if any,
needed at a sjte requires an understanding of the hazards posed by the site
under investigation. This chapter presents a brief assessment of the con—
tamir-ltion at the Smuggler site. Section 3.2. discusses the groundwater
pathway by which the contaminants present at the site may migrate to impact
gruundwater receptors. Section 3.2 susm arlzes the groundwater endangerment
scenarios developed at the Centennial site. Section 3.3 discusses esta-
blishment of an environmental protection goal, based on the results of the
groundwater contamination assessment. The environmental protection goal is
used to assess the adequacy of the no—action alternative as well as any
reco endsd remedial action alternatives.
3.1 Groundwater Contaminant Migration Pathways
Th. sourc. of contamination at the Smuggler site is solid wastes. The
solid wastes Include mine wastes, mill tailings, and smelter wastes that
were generated from silver, lead, and zinc mining. As previously mentioned,
It is estimated that undisturbed mine tailings make up approximately 25
percent of the 75 acre area, and 50 percent is comprised of a complex mix-
ture of mine and mill tailings, native soil, and fill material (E&E 1984a).
Potential migration pathways for these wastes include: air, surface water,
groundwater, and there is some potential for direct contact with the con-
taminants at the site.
- A study Is currently planned address the type and amount of surface
remedlation necessary to mitigate risks caused by the occur.nce of heavy
metals at the site. A final feasibility study will set cleanup criteria at
the stated action levels from EPA’s risk assessment.
BioavailabilIty and acute toxicity posed by heavy metals and soils at
the site via direct contact or inhalation exposure routes, however, are not
the only concerns for proper remediation.’ Since heavy metals could leach
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into local aquifers, groundwater users could be at risk, and regional
groundwater supplies could be damaged. There has been in conclusive
evidence of current contamination of local receptor wells, although, ft is
generally agreed that future risks to groundwater and groundwater users have
not been Identified or characterized.
Based on previous work, the concept of groundwater flow is well under-
stood at the site. Due to the complex geologic conditions at the site
caused by the occurrence of groundwater through fractured bedrock flow
systems, and extensive mining, it Is doubtful that any study regardless of
cost could ever provide reliable local data to support groundwater remedia-
tion alternative designs.
The purpos. of this Focused Feasibility Study is to determine the
alternatives available for groundwater remedlatlon at the site. In the
event that the present data base will not technically support attractive
alternative remedial designs, this study will outline data gaps and propose
additional study requirements which could be performed during the study
planned to define the limits of the site. A final Feasibility Study wf 11 be
included In that study to reco ’end a conceptual design for mitigation of
risks posed by all media at the site.
The risk associated with the groundwater media is considered to be
moderate. There is some potential for largely insoluble heavy metals to be
leached by infiltrating rainfall. In addition, the groundwater media could
contribute to the contamination of surface water through the interface
between alluvial groundwater and the iurface waters i n the Roaring Fork
River and Hunter Creek. Potential receptors 1 ncluoe human and animal popu-
lations ingesting surface waters from Roaring Forks and Hunter Creek Rivers
and persons ingesting contaminated groundwater obtained from the alluvial
a a . . • • . . I I I I I I • • I
dquuler. uua i wvui uujut. u pu .vtu.u t WI UhIId SUII $tII.lUU d$J J(VAI
mataly five residential wells located between the site and Roaring Fork
River.
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Off-site groundwater Contamination at levels approaching state and
federal drinking water standards have been demonstrated by previous studies
(Ecolo i and Environment 1984a). Although elevated levels of metals in
these wells c ld be indicative of ore deposits, mining operations, or well
constructiorc materials, they nay also, at least in part, be associated with
the Smuggler Site. Future groundwater development in the area could be
limited by the occurrence of this contamination, however, future use of this
aquifer is prohibited in Pitkin County. Future wills drawing on the alluvial
aquifer adjacent to the Smuggler site could be endangered by this contanhina-
tion.
3.2 Endangerment Scenarios
Having enumerated the threats of contamination posed by the uncovered,
unst.abilizsd tailings and mixed soils at the Smuggler site, this section
will proceed on the assumption that the Centennial site poses a relativ ly
well—established and predictable threat of transmission through air, surface
wateriand direct contact, and a moderate to high threat through the medium
of groundwater. Since a site definition study is currently planned, this
section will focus on the groundwater media only.
Although concentrations of two heavy metals significantly higher than
backgrobnd have been found in samples of alluvial groundwater, the presence
of mineralized zones in the bedrock in the vicinity of the Smuggler site
destroys all simple sourcr’pathwarreceptor analysis.
- As the geological description of the site indicates, the ,fractured
bedrock underlying much of Smuggler Mountain contains mineralized zones,
several of which were mined. Regionally, rain and snowmelt percolating down
the interior of the mountain forms a horizontal flow downgradient in the
direction of the alluvial aquifer In the valley. Water In the bedrock
aquifer percolates through the mineralized zones and through the abandoned
mining areas as it travels to discharge into the alluvial aquifer below and
downstope of the Smuggler site. Hence, the contamination of heavy metals
found in the alluvial aquifer may be due to the transmission of heavy metals
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from the bedrock inside Smuggler Mountain, a plums of contamination from the
Smuggler site, or some combination of the two.
Further complicating this source—pathway—receptor analysis is the fact
that a plume from the Centennial site would have to percolate vertically
through alluvial deposits into the bedrock then horizontally out of the
bedrock back into the alluvial deposits downgradient to the location of the
private wells In the residential area. This Is due to the way in which the
Smuggler site Is situated at the edge of the valley deposits, nestled
against the mountain at the point where bedrock is no longer covere&by the
alluvial deposits.
Potentially, as rain and snowmslt continue to percolate vertically
through the Smuggler Sits, the site could eventually have at least some
role, If It does not already exist, In contaminating the alluvial aquifer
used by resld nts downgradlent of the sits. Furthermore, as time goes ‘bn,
chemical changes in the heavy metal laden tailings may render those metals
more likely to leach, thus accelerating the above-described process.
Sumary . In accounting for the contamination found in the private
wells drawing on the alluvial aquifer, it is Impossible to distinguish
between contamination that may be caused by the natural condition of the
nearby bedrock and contamination that may be caused by the heavy ntetal-lader
tailings at the Smuggler sits. However a moderate risk of exposure to
groundwater receptors can be attributed to the continued presence of Smug
gler site In its present stats.
3.3 Environa.ntal Protection Goals
Th. overall goal is to minimize the actual or potential reiease of naz-
r cus substances into the environmsr.t from the site. Where direct study
allows for a precise identification of those threats, both actual and poten-
tial, precise remedial steps can be taken to arrest contamination through
available media, as in the case of air, surface water and direct contact.
Where such identification is confounded by geological ambiguities, as in the
case of groundwater, means of abatement must be undertaken commensurate w th
reasonably established parameters of potential harm.
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The specific environmental goal for the Smuggler site is to insure the
protection of the health of residents in the area. Goals for the mitigation
of surface releases have been extablished by EPA in the form of a risk
assessment. Specific environmental goals with respect to groundwater are to
mitigate the threat of exposure to present and future users of the grour —
water supply.
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Smuggler Mountain Mining Waste NPL Site Summary Report
Reference 6
Excerpts From Addendum - Remedial InvestigationlFeasibility Study,
Smuggler Mountain, Colorado, Document No. 149-WP1-RT -CMYB-1;
Prepared for EPA; Undated
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SF FiLE NUMBER
‘ -1. 7 ADDENDUM
- REMEDIAL INVEST!GAT Qpi/FEASI3 LITy STUDY
OI T r1vE RECORD SMUGGLER UNTAIN, CO
Document No.: 149-WP1-RT-CMYB—1
I 1TRODUCTI0N AND 3ACKGROUND
This addendum is prepared by the REM II Team as a portion of our tecinical
oversight support for the Smuggler Mountain Site. It will suppleient an
clarify the RI/FS (Hart 1986) prepared consistent with a consent or e’-. It
also will reference the National Contingency Plan where app’opria:e. The
addendum is presented in sections to address U) additional R da a and
analysis, by discipline, and (2) additional FS analysis, by discipline,
especially concerning alternatives analysis and applicaole or relevant an
aporopriate requirements. An overall assessment of cost—effectiveness, : “
conparative cost estimates, ar.a other alternatives analysis criteria is
also included.
As background, the REM II Team was initially assigned the RI/FS or t.ilZ
site. Following negotiations with trte PRPs, EPA approved P P plans :
c3nduct the RI/FS, and a final . I/FS report was suoriitted in ea”ly L 35.
The REM II Team s assigned a Technical Oversight r ie. This Addendum is
another oversight effort of the REM II Team.
REMEDIAL INVESTIGATION (RI)
Soil/Tail ings
EPA has through the endangerment assessment process establisned a 1,300 pm
Pb action level in soil and tailings to define the site boundaries of
Smuggler Mountain. Various schemes have been pr000sad by the EPA, trie REI
II Team, and others to define the site, eac i with its advanta as arid
isadvantages. 4owever, for purposes of trie health risk at the 5rin ggler
site, a final endangerment assessment (Clement 1925) has been prepares
022829
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TABLE 1
SOIL ANALYSIS FOR RADIOACTIVITY
Parameter
unIts
Location
71
10
104
37
118
78
16
94
120
43
Radium 226
pCI/g
3.4+0.1
1.5+0.1
5.9+0.1
6.6+0.1
3.8+0.1
4.7+0.1
5.6+0.1
1.8+0.1
1.4+0.1
1.2+0.1
Gross alpha
pCl/g
28
15
56
48
27
31
44
31
22
15
Uranium
pba
escr Iptionb
ug/g
ug/g
——-
20
21,694
CP
3.2
704
MV
45
9450
MF
14
3,840
MV
9.4
5,300
I
11
517
F/NS
15
5,210
T
13
237
NS
2.0
347
NS
1.3
225
F
a) X-MET value.
b) CDII Field Classification.
HF • Mixed fill w/ta llings
I Tailings
F = Fill w/out Tailings
NS • Native soil
CP • Chemical precipitate
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It is apparent that the potential for contamination of the hydrologic
system Is dependent on the chemical Interaction between water and
tailings/fill. From existing data, it is likely that such Interaction
involving s urface water is Confined to the marshy area adjacent to the
Cowenhoven drainage. The potential geochemical Implications, as well as
the probable role of ground water, is discussed in the following section.
Ground Water
Ground water beneath the Smuggler site occurs in both unconsolidated
surficlal deposits, and within the underlying sedimentary bedrock strata.
As stated in the RI/FS report, the bedrock system is decidedly complex,
with extensive faulting and fracturing which controls the occurrence and
flow of ground water in undisturbed strata. The aquifer(s) are further
complicated by underground mine workings, which probably represent the
preferred ground water flow paths. In general, however, the bedrock ground
water system is of minor importance, due to (1) limited existing ground
water use, (2) limited potential for future development, and (3)
significantly greater use, and potential for use, associated with the
alluvial aquifer of the Roaring Fork River valley. The importance of
bedrock ground water, therefore, Is restricted to its role, if any, in
recharging the alluvial system. Based on existing knowledge of the site,
the majority of such recharge is provided by discharges from the Cowenhoven
and Mollie Gibson adits. The unsaturated to slightly saturated conditions
in evidence from wells and boreholes between and upsiope of these adits
indicates that any other bedrock contributions are negligible.
Considerably more is kno m regarding the surficlal unconsolidated aquifer.
Monitor wells installed by the FIT in February 1985 (4 wells) and by the
REM II team In October 1985 (4 wells) clearly show that saturated deposits
beneath the site are In direct communication with ground water In the
alluviic of the Roaring Fork Valley, in an unconfined aquifer system.
Water levels measured from six of the eight wells during November 1985,
February 1986, and April 1986 exhibIt a piezometric surface which parallels
the Roaring Fork River; i.e. flowing in a down—valley, northwesterly
direction. The remaining two wells, located upslope from the valley
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bottom, exhibit unsaturated conditions, indicating that ground water
occurrence Is limited to beneath the lower slope areas comprising the
southwest half of the site. AS noted above, some recharge to this aquifer
may occur from the Mollie Gibson and Cowenhoven adits; the direct
infiltration of incident precipitation and surficlal runoff undoubtedly
also provides some recharge. Based on the piezometric data, however, it is
apparent that the large majority of recharge occurs as underfiow in the
alluvial system from up the Roaring Fork Valley. As such, monitor Well 1
is established as an upgradierit well, Well 5 as downgradient, and Wells 7,
8, 9 and 10 are situated within the site itself.
Ground water chemistry data from these six monitor wells have been
collected in November 1985 and February 1986; a third sampling effort was
performed during the week of May 12, 1986 (data not yet available). These
November and February data are presented in Tables 2 and 3. Of particular
importance to the RI#’FS is the absence of lead in all samples, and the
occurrence of cadmium in Well 7 (both sampling rounds) and Well 5 (November
1985 only; the well was unsaturated In February 1.986). A slight increase
in cadmium, from 0.007 to 0.010 mg/L, occurred between the two sampling
periods. Zinc concentrations are also highest in Well 7 for both sampling
periods. Given the absence of cadmium in both the upgradient well (No.1)
and the Mollie Gibson and Cowenfloven discharges, the data indicate that the
occurrence may be a localized phenomenon, potentially as a result of
tailings. Data collected for the RI/FS suggest that the acid-forming
potential of the soils Is negligible, attributable to an abundance of
calcium carbonate In the host rock. These conclusions are valid, but based
on a very limited number 0 f samples. There may be significant potential,
therefore, for localized pockets of tailings to produce acidic conditions
if they are derived from the ucoreN of the mineralized zone with a low
percentage of buffering calcium carbonate. Further monitoring is
therefore warranted in all wells.
Because of the potential for elevated concentrations of radioactivity,
selected ground water samples were analyzed for radlum-226, gross alpha and
uranium. The samples were split from those collected by REM I I personnel
and were analyzed by EPA ’s Region V I I ! laboratory. The results of the
—12—
-------
TABLE 2
GROUND WATER ANALYSES FOR NOVEMBER 1985
Parameter
Well
No.
GW-1
GW-5
GW-7
GW-8
GW-9
GW-10
Arsenic
ND
ND
ND
ND
ND
ND
Cadmium
ND
0.004
0.007
MD
ND
ND
Calcium
4.59
136
143
20
119
128
Iron
ND
ND
ND
ND
ND
ND
Lead
ND
ND
ND
ND
ND
ND
Magnesilml
14.1
23.8
52.5
5.74
38.5
36.8
Manganese
Potassium
0.017
ND
MD
MD
0.052
1.92
ND
MD
MD
ND
0.043
MD
Sodium
20.5
9.69
6.68
4.1.6
ND
6.35
Zinc
0.062
0.060
1.00
0.018
0.413
0.053
Concentrations In mg/I; metals are dissolved.
Validation criteria qualifiers pertain to some data; details are included
in REM II files.
Source: CDM 1986.
Notes :
‘7 / -
-------
TABLE 3
GROUND WATER ANALYSES FOR FEBRUARY 1986
Para ter
(Mits
Well
No.
6W-i
6W-S
6W- i
6W-B
GW-9
GW-lO
Arsenic
ag/i
ND
Dry
ND
ND
ND
ND
Cadmium
ag/i
ND
Dry
0.010
ND
ND
ND
Calcium
ag/i
46.5
Dry
168
22.3
120
136
Iron
mg/i
0.034
Dry
0.121
0.026
0.022
0.086
Lead
mg/i
ND
Dry
ND
ND
ND
ND
Magnesium
Manganese
Potassium
Sodium
ag/i
ag/i
ag/i
mg/i
14.5
0.025
0.95
19.4
Dry
Dry
Dry
Dry
53.9
0.226
2.43
4.95
6.2
0.05
ND
0.93
41.2
ND
1.49
3.91
39.5
0.174
1.64
6.19
Zinc
mg/i
0.020
Dry
1.44
0.065
0.460
0.066
Oil and Grease
TOC
ag/i
ag/i
1.1
15
Dry
Dry
2.2
2.1
1.4
4.6
ND
4.9
ND
1.7
Chloride
ag/i
29
Dry
ND
ND
N I)
30
Sulfate
ag/i
ii i
Dry
215
30
313
220
Bicarbonate
ag/i
54
Dry
180
49
162
199
TDS
Radiu.-226
Gross alpha
Uranium
ag/i
pCi/i
pCi/i
mg/i
280
0.45 0.02
3
0.0024
Dry
Dry
Dry
Dry
905
0.45 + 0.02
140
0.310
95
0.21 + 0.01
4
0.00021
625
0.34 • 002 a
120 a
0 230 a
625
0.37 + 0.02
11 —
0.036
Validation criteria qualifiers pertain to so data and are included In REM II files.
a) Duplicate values:
Radiua-236 0.36 0.02
Gross Alpha 100
Uranium 0.210
Source: CON 1986.
-------
analyses are provided In Table 3. As shown, higher concentrations of
uranhimi and gross alpha exist in Wells 7 and 9. The current MCI under the
Safe Drinking Water Act Is 5 pCI/i for the combined total of radium-225 and
raditmi—228. The standard for gross alpha (excluding uranium and radhmi) is
15 pCI/i. In addition, Colorado has a guidance level of 10 pCI/i (about
0.015 mg/i) for uranium. Comparison of these standards and the values
shown in Table 3 IndIcate that elevated levels of gross alpha and uranium
may exist. However, the gross alpha values reported on Table 3 by the
laboratory Include the radioactivity contributed by all emitters except
radon, but Including uranium. Therefore, to compare these values with the
standard for gross alpha, the contribution of the uranium to the gross
alpha radioactivity should be removed. By correcting the reported gross
alpha concentration for uranium using the value of 677pC1/ing of uranium,
the values do not exceed the standard for gross alpha. However, the
uranium values for GW—7, GW—9, and GW—10 do exceed the Colorado guidance
level. In addition, substantially higher values for uranium and gross
alpha were measured in samples from Wells 7 and 9. This observation is
consistent with the wells showing higher TDS and trace metal
concentrations. Because radioactivity, appears to be only associated with
the tailings (see Table 1), the results at Well 7 and 9 may indicate that
leaching of tailings Is occurring. As previously recommended, these wells
should continue to be monitored for radlonuclides.
Because 0 f the potential of surface waters to recharge ground water, the
interaction of the surface water with minerals contained in the tailings
and host rock was modeled using the computer program PHREEQE (Parkhurst
t980). PHRE QE is a thermodynamic based program used to model equilibrium
water/rock interactions under a variety of pH and oxidation/reduction
conditions. In particular, the Interaction of waters from the Cowenhoven
and Mollie Gibson drainages with minerals assumed to be present at the
Smuggler site were modeled at the following conditions:
pH: 6.4 to 7.1 s.u.
Eh: -200 to +400 my
—15—
-------
4. The proposed county Park area and Smuggler Mine No. 2
tailings pile and vicinity show visually the largest
remaining area of tailings and apparent contaminated
material, totaling several acres in extent.
Detailed comments on the field visit are included In the trip report (CDM
1986).
Movement of contaminated materials to a repository on—site by the PRPs is
yet under negotiation. REM II comments regarding PRP estimated costs for
excavation and removal are addressed in a later section of this document.
Remedial design for capping and removal efforts will be addressed in a
forthcoming Work Plan and Remedial Design Oversight Report prepared by the
REM II Team.
Surface Water
Result from the RI indicate that the existing surface water system,
including the Cowenhoven and Mollie Gibson drainages, Hunter Creek, and the
Roaring Fork River, has not been contaminated by on—site tailings. The
latter two streams exhibit consistently low major ionic and trace metal
concentrations. The mine drainages are typified by moderate to high
concentrations of selected metals, including zinc, manganese, and iron, but
these constituents are not attributable to dissolution of the tailings nor
are they considered a significant threat to public health. For these
reasons, site remediation must focus on ensuring that surface water
conditions are consistent with other protective measures; remediation of
the surface water drainages themselves is not warranted. This approach is
consistent with the findings of the RI/FS. Critical components of the
surface water system which may affect site remediation are as follows:
1. Infiltration through tailings and contaminated fill, potentially
leaching metals into the ground water system.
2. ErosIon of tailings and contaminated fill, either by existing mine
drainage channels or overland flow.
3. InstabilIty of the cap and/or other surface remedies due to
erosion by surface water.
—21-
-------
1
Smuggler Mountain Mining Waste NPL Site Summary Report
Reference 7
Excerpts From Potential Hazardous Waste Site Identification
and Preliminary Assessment, Smuggler Mine Site;
EPA Region VIII;
March 31, 1984
-------
PRELIMINARY ASSESSMENT
SITE INSPECTION
HAZARD RANKING EVALUATION
FOR THE
SMUGGLER MINE
ASPEN, COLORADO
TDD R8-8403-13
SUBMITTED TO: KEITH SCHWAB, FIT, RPO
LINDA BOORNAZIAN, REM, RPO
SUBMITTED BY: GEOFFREY UPSON - PROJECT OFFICER
JEFFREY FOSTER
DATE SUBMITTED: APRIL 5, 1984
022745
-------
________________________ - - Rt .G ION i T
a POTENT:AL. flAZ. RDCuS WASTE SITE j•lJ wI4b,HV
IDENTIFICAT 1OK A 4D PRELIMINARY ASSESSMENT C0D980806277
HOTS: rbi. foim is crmp).t.d tot ..h potundat b.s&rdous waste site to help set priorlu.. for C I I . In speciJon. The nlo at efl
•ub ittsd o this (oem is bused on availsblo ,.cotds sod may be updated on subuqusnt form. es a resuit Of additionsi megan..
sod ..t1i iaspcUoos.
C!NERAL INSTRUCTIOMS: Compist. S.c oas I and UI throu t 1 se CowplSt.ly as passable before Section Ii (Preliminary
4.... .nt) PU. hi. form In tha.R.tltonsl H.zadOu$ Vaste L.o Pil e and submit a copy to U.S. Ea itonii.ntal Proiectio
A100cr. alt. Tracking Syst.s; Has.?e%as Vast. !.nfovcement Task Po,vs (EN-333)-. 401 N St.. SS; Vaziw,f on, DC 20460.
I. SITE IDENTIFICATION
.
SITE NAME
S. STREET 1 (.’
.ffi., id .At .t..r)
—
Smuggler
Mine
N/A
:.
CITY
Q• STATE
C. ZIP CODE
F. COUNTY
NAN(
Aspen
CO
81611
Pitkin
;.OwN/OPErnATOrn(OI s.rm) .
I. Na 5
See Addendum
i. TYPE OF OWNERSH
D i. FEDI AL
IP
D L STATE Z COUNTY
D MUN’C’PAI.
Z PRIVATE
4 UW NOe ’i
SITE DESCRIPTION
A lead—silver
mining
operation
(intermittent
operation)
with
adjacent
mine and mill
tailings from
previous local mining operations.
• NOW IOENTIFIE.. ...... ca ll.. .. ses,l•Ml .. OSNA I,.u.aa. .rc ., R ea h into cro k . DATE lIEN TIdED
uptake of trace metals indicated a potentia y Iriou prod’iem with thá ,Q.. yr.)
uptake of lead and cadmium by vegetables grown on regraded mine and mull
t i1in c (Rnrmn’ - I
PRINCIIAL S 5 .t CONTACT Municipal — Mr. Tom Dunlop, City of Aspen, Env. (303) 925-2020
Health Dept. V AL’
County — Mr. Patrick Dobie, Pitkin Cty. Eng. Dept. (303) 925-6527
Li. P ELI’nINARY
ASS
ESSMENT (
CompleI. (his secHor
APPARENT SE
RIOUSNESS Or PROSLEM
Qi. HIGH
2. MEDIUM
Q3
LOW
Qi
NONE
5 UNKNOWN
I. R C C 0 NMEWOA TI OM : A lead biuui.rnim.uring St..uuy ror young cnuioren iu years is recomena
I. NO ACTION NEEDED (..A.wd) 2 MMCOIATE StC IwSnE’IOP. wsc:
5 YCi .8YvkL. 5C,.CULc ace
3. SITE IN P!CTlON NEEDED
T(w,4Y.V b •CnLDui.CD FOR t• St • S OSb t
b. es s. IC PIAPOnse4Dse
ITI INSPECTION NC!OCD II.w pne,,,7 )
Site Sampling completed September 1983 and November 1983. _________
PREPAP1ER INFORMATION
3 T(LFC .,3NI iR
Geoffrey L. Upson (303)757—4984 March 31, 1984
111. ITEti’4FORMATlON ______
A. SITE STATUS
I. ACTIVI r... i..ot..., - 2. INACTIVE 17 ) ... ). OTWES .,p.c:P,,
a..irIpal . 11.. .M4A . t.M4 u..d • • .. .na.li na Son,r mesS.. (TIi... .u.i •‘,a, u,el 5. ... A c.i *nS Sia. . “2”
t..r .... Ir..i..*I, •.toa.. .v d,.,..al mWaS.•.) n. r.j sr a. e•. .. ..ving we. i( e si. I.. .‘.,ie CS .? , . .. ACC .,eCg 3.r
• 5 es.SrmM3 b..I.. ,1•ø II MO .— I
S. IS GEP ,EAATOR ON SIT Ct
Qi. NO YES (.p.dlSy wm .iSw• I ... —d. .i tC C.. N/A ______
C.AIC SITE (Sw . . ,..) 0. IF APPAb. HT N’Ot.,iuES O $IY( i N, PI. s0:Ir •
I. L T,TU C . i .Q.. . lu- I. (J.4. i”. —..s)
75 acres ___________ 390 11’ 30” North ____ j 106° 481 361 West ___
E.AMECRCS ..DINGSON1MCSITL?Mine Buildino on the Smugaler Mine Site. Sinole family —
Du.wo z.vCs(.....u,J dwellings,Trãiler court, Tennis club, Condominiums and Apartr nts.
, P
-------
Smuggler Mountain Mining Waste NPL Site Summary Report
Reference 8
Personal Communication Concerning Smuggler Mountain;
From Laurie Lamb, SAIC, to Bob Elkington, EPA Region VIII;
May 10, 1991
-------
57D
PERSONAL COMMUNICATION
SUMMARY REPORT
SAIC Contact: Laurie Lamb Date: 5/10/91 Time: 9:00 a.m.
Meeting at SAIC — Meeting at EPA .
Person(s) Contacted (Organization): Bob Elkington, Assistant to Paula Schmittdial
Subject: Discussion of Smuggler Mountain NPL Site Summary, RPM Smuggler Mountain
Summary: Bob displayed a map of Operable Unit 1 boundaries. Operable Unit 2 has no defined
boundary at this time. The mine site is updip from Mollie Gibson Park. Virtually nothing has been
done on Operable Unit 2.
Two repositories are in the planning stage. The first to be constructed and used will be the Racquet
Club repository, which will have a design capacity of 9,000 cubic yards.
The Salvation Ditch project is currently underway. It requires the redirection of the ditch to make way
for the Mollie Gibson repository in Mollie Gibson Park. The expected completion date is June 1. BOR
is the prime contractor for the site. Remediation will begin on August 2. Design engineers have been
meeting with property owoers to work Out the details. The Mollie Gibson repository has a design
capacity of 45,000 cubic yards. Most remediation will be completed by the end of next summer.
Operable Unit 1 Is a 116-acre site (90 percent of it is developed).
In 1988, Jacobs Engineering collected 1,000 samples from 0 to 4 feet and analyzed them using XRF.
Camp, Dresser and McKee’s 1990 sampling included 3,300 samples (1,100 locations and 3 samples at
each location at defined depths of 0 to 2 inches; 2 to 6 inches; and 6 to 12 inches. XRF was used to
analyze for lead concentrations.
The geometricmean for all lead samples was - 6,577 ppm (all depths); the mathematic lead mean was
2,084 ppm; the lead action level was 1,000 ppm.
The ranges In concentration were from 0 to approximately 107,000 ppm.
• 0 to 500 ppm -49 percent of samples
• 500 to 1,000 ppm - 16 percent of samples
• Greater than 1,000 ppm -35 percent of samples.
-------
5 71
( t\
Mining Waste NPL Site Summary Report
St. Louis Airport!
Hazeiwood Interim Storage!
Futura Coatings Company Site
St. Louis County, Missouri
U.S. Environmental Protection Agency
Office of Solid Waste
June 21, 1991
FINAL DRAFT
Prepared by:
Science Applications International Corporation
Environmental and Health Sciences Group
7600-A Leesburg Pike
Falls Church, Virginia 22043
-------
DISCLAIMER AND ACKNOWLEDGEMENTS
The mention of company or product names is not to be considered an
endorsement by the U.S. Government or by the U.S. Environmental
Protection Agency (EPA). This document was prepared by Science
Applications International Corporation (SAIC) in partial fulfillment of
EPA Contract Number 68-WO-0025, Work Assignment Number 20.
A previous draft of this report was reviewed by Greg McCabe of EPA
Region VII [ (913) 551-7709], the Remedial Project Manager for the
site, whose comments have been incorporated into the report.
-------
Mining Waste NPL Site Summary Report
ST. LOUIS AIRPORT/
HAZELWOOD INTERIM STORAGE/
FUTURA COATINGS COMPANY SITE
ST. LOUIS COUNTY, MISSOURI
INTRODUCTION
This Site Summary Report for the St. Louis Airport/Hazeiwood Interim Storage/Futura Coatings
Company Site is one of a series of reports on mining sites on the National Priorities List (NPL). The
reports have been prepared to support EPA’s mining program activities. In general, these reports
summarize types of environmental damages and associated mining waste management practices at sites
on (or proposed for) the NPL as of February 11, 1991 (56 Federal Register 5598). This summary
report is based on information obtained from EPA files and reports and on a review of the summary
by the EPA Region V II Remedial Project Manager for the site, Greg McCabe.
SITE OVERVIEW
The NPL site consists of three areas: the St. Louis Airport location immediately north of the St.
Louis International Airport; the Hazeiwood Interim Storage area on Latty Avenue .5 mile north of the
Airport location; and the Futura Coatings Company property, adjacent to the Hazelwood Storage
area. These three properties total 33 acres; (see Figure 1) (Reference 1, pages 10 through 13;
Reference 2, page 2). The three areas, located in an industrial section of St Louis County
approximately 15 miles northwest of downtown St. Louis, were used for the storage of residues
resulting from offsite uranium processing at a facility located in downtown St. Louis (Reference 2,
page 4). Historic management practices resulted in the contamination of soil at the site. In addition,
some wastes stored in these areas remain onsite. Constituents of concern at the site are uranium,
thorium, radium, and radon.
Operation of the downtown facility and the Airport location was conducted by the Manhattan
Engineering District in the 1940’s and 1950’s. None of the areas are presently owned or operated by
the Department of Energy (DOE) (Reference 2, page 4; Reference 3, page 2). All three areas are
under investigation through the DOE’s Formerly Utilized Sites Remedial Action Program (Reference
1, page 2). An agreement between DOE and EPA was finalized in August 1990, giving DOE
authority to conduct all remedial actions and giving the EPA oversight authority (Reference 4). Some
remedial actions, described in the next section, were conducted in 1984 and 1986. No further
remedial actions are scheduled prior to the signing of a Record of Decision (ROD), expected in 1994
(Reference 3, page 19).
1
-------
C,)
I .
•1
I
I
I
COLOWATIN CRIEK
4
10 U MIt U TO
DOWNtOWN AT LOUIS
• SI INS
• SIMs
-------
Mining Waste NPL Site Summary Report
OPERATING HISTORY
Storage of uranium ore processing residues at the St. Louis Airport location began in 1946 by the
Manhattan Engineering District (MED) (Reference 2, page 4). The Airport location was used to store
residues from a uranium ore processing facility in St. Louis, which operated under a MED and
Atomic Energy Commission (AEC) contract until 1957 (Reference 5, pages 5 and 8).
Residues sent to the St. Louis Airport location included pitchblende raffinate residues, radium-bearing
residues, barium sulfate cake, Colorado rafflnate residues, and contaminated scrap. Most residues
were stored (in bulk) as drums or metal scrap on open ground, although some were buried onsite
(Reference 5, page 8; Reference 6).
In 1966, residues stored at the Airport location were moved to the Hazelwood Interim Storage area .5
mile north of the Airport location (Reference 2, page 4). Also in 1966, Continental Mining and
Milling Company acquired the Hazelwood Storage area property and recovered uranium from wastes.
The company sold the property the following year (Reference 6). Residues on the Hazelwood Storage
area in 1966 included 74,000 tons of pitchblende raffinate, 32,500 tons of Colorado raffinate, 8,700
tons of leached barium sulfate, and a total of approximately 68 tons of uranium (Reference 7, page
4). Some residues were sold to a Colorado facility from 1967 to 1973, while the leached barium
sulfate was transported to a St. Louis County landfill.
Since the 1970’s, Futura Coatings has leased the western portion of the Hazelwood Storage area. The
facility is used for plastic coatings manufacturing and is unrelated to mining activities.
In August 1979, approximately 13,000 cubic yards of contaminated soil from the Hazelwood Storage
area was excavated and stockpiled on the property. In 1984, DOE conducted remedial actions in the
area, as directed by the 1985 Energy and Water Appropriations Act (Reference 5, page 8; Reference
6). As a result of remedial actions and construction activities on adjacent properties and at Laity
Avenue in 1984 and 1986, an additional 18,600 cubic yards of soil was placed on the property. As
of 1986, two piles of contaminated soil, totaling 32,000 cubic yards, were located on the Hazelwood
Interim Storage area (Reference 7, page 5). As of 1988, a total of 4,100 tons of contaminated scrap
and residues were at the Airport location (Reference 1, page 28).
SITE CHARACTERIZATION
Characterization activities were performed by DOE as early as 1976, but the most extensive
characterization of the site was performed by DOE from 1985 to 1987 to determine the extent of
offtite soil contamination and to characterize onsite soil and ground water (Reference 7, pages 9 and
3
-------
St. Louis Airport/Hazeiwood/Futura
10; Reference 2, page 11). Ongoing monitoring activities, consisting of ground-water, surface-water,
creek sediment, and air sampling, have been performed at the St. Louis Airport location annually by
DOE since 1984. Airborne release of contaminants is the primary exposure route at the site
(Reference 1, page 45).
Two ground-water systems underlie the St. Louis Airport location. The first system consists of an
upper, unconsolidated glacial deposit at a depth of 11 to 35 feet, and a lower glacial sediment deposit
at a depth of 35 to 87 feet. Flow in both deposits is east to west, towards Coldwater Creek. The
second system is a bedrock limestone aquifer several hundred feet below the area, of generally poorer
quality (Reference 5, pages 4, 5, 13, and 16 through 20). The well nearest the Airport location is
approximately 1.5 miles north (Reference 5, page 5). Ground-water flow at the Hazelwood Storage
area is reported to be towards Coldwater Creek (Reference 1, page 44). The Airport location is
adjacent to Coldwater Creek, while the Hazeiwood Storage area and the Futura property are less than
500 feet east of Coidwater Creek (Reference 2, page 7).
Air
Annual average levels of radon-222 were measured at nine perimeter locations at the Airport area in
1988. Average levels of radon-222 at the Futura property were reported from building interiors.
Average levels of radon-222 at the Hazelwood Storage area were reported from unknown monitoring
locations. Studies were performed by DOE and the results are presented below (in ranges) in Table I
(Reference 5, pages 27 through 33; Reference 1, pages 42 and 73 through 76).
TABLE 1. ONSITE RADON-222 CONCENTRATION IN AIR pCi/I (IN RANGES)
Airport
Hazeiwood
Futura
Background
0.7
-2.1
0.2-
1.8
0.3
-0.7
0.4-0.5
A standard of 3 pico Curies per liter (pCi/l) has been established for radon-222 by the Nuclear
Regulatory Commission as the maximum permissible concentration for air in unrestricted areas
(Reference 1, page 43).
Levels of gamma radiation exposure were measured at perimeter locations at the Airport area. Levels
of gamma radiation at the Futura property were reported from building exteriors. Levels of gamma
radiation at the Hazelwood Storage area were reported from unknown monitoring locations. Results
of these measurements are presented below (in ranges) in Table 2.
4
C 1
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Mining Waste NFL Site Summary Report
TABLE 2. ONSITE GAMMA RADIATION EXPOSURE, IN AIR ( RJhr) (IN RANGES)
Airport
Hazelwood
Futura
Background
9-261
13-55
8-27
8
Based on data collected annually from 1984 to 1988, levels of radon and exposure to gamma radiation
in the air have remained constant at the Airport location (Reference 5, pages 43 through 46). No
information concerning trends at the other locations was provided.
Surface Water
Annual average radioactive constituent concentrations of Coldwater Creek water were measured 15
meters north (downstream) of the St. Louis Airport location boundary and at an upstream location in
1988. Coldwater Creek water quality was measured at the Hazelwood Storage area in 1986
(Reference 1, page 41; Reference 5, pages 33 through 35). Upstream concentrations were reported to
provide background data. Surface-water contaminant levels are near background at the Airport
location. Although no conclusions concerning levels of thorium in surface water from the Hazelwood
Storage area were provided, results are provided below in Table 3.
TABLE 3. COLDWATER CREEK WATER CONCENTRATION, (IN pCi/I)
Constituent
Airport
Hazelwood
Upstream
Uranium (total)
4
<3 - 5
4
Radium-226
0.3
0.1 - 0.4
0.5
Thorium-230
0.3
<0.1 - 1
0.1
Based on data collected annually from 1984 to 1988, levels of uranium, radium-226, and thorium-230
in surface water have remained constant at the Airport location (Reference 5, pages 43 and 47). No
information concerning trends at the other locations was provided.
5
-------
St. Louis AirporuHazeiwood/Futura
Sediments
Annual average contaminant levels of Coldwater Creek sediments were measured at the same
upstream and downstream locations as the surface-water samples (Reference 1, page 41; Reference 5,
page 39). Upstream concentrations were reported to provide background data. Results are provided
below in Table 4. No conclusions concerning levels of thorium in sediments from the Hazelwood
Storage area were presented.
TABLE 4. COLDWATER CREEK WATER CONCENTRATION (IN pCilg) DRY WEIGHT
Constituent
Airport
Hazelwood
Upstream
Uranium (total)
2.6
5.6
1.7
Radium-226
1.0
5.6
1.5
Thorium-230
5.4
200
1.3
Ground Water
At the St. Louis Airport location, an unknown number of ground-water monitoring wells were
installed in 1981, 10 wells were installed in 1986, and 27 wells were installed in 1988 (Reference 5,
page 9). The ranges of average levels of constituents measured quarterly in 1988 from each of 16
onsite wells are presented below in Table 5 (Reference 5, pages 34 through 38). Data from the
Hazelwood Storage area is from the 1986 DOE annual report, while a source of the Futura data was
not provided (Reference 1, pages 40 and 47 through 49). High levels of uranium in ground-water
monitoring wells at the Airport location reportedly result from subsurface soil contamination
(Reference 5, page 38). Conclusions regarding thorium levels at the Airport location, as well as
conclusions regarding uranium and thorium levels at the Hazeiwood Storage area, were not given.
Levels of all three constituents at the Futura property are near background.
TABLE S. GROUNDWATER CONCENTRATION (IN pCiIl) (IN RANGES)
Constituent
Airport
Hazelwood
Futura
Background
Uranium (total)
<3 - 5,590
<3 - 33
<3 - 6
3 - 4
Radium-226
0.3 -0.9
0.1 - 0.7
0.6 - 1.3
0.6 - 1.1
Thorium-230
0.3 - 52
<0.1 - 1
0.1 - 0.4
0.2
6
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Mining Waste NPL Site Summary Report
Based on data collected annually from 1984 to 1988, levels of radium-226 and thorium-230 have
remained constant. Levels of uranium in two wells increased in 1988 while remaining stable in five
others (Reference 5, pages 43 and 48 through 50). No explanation for the increase in these wells was
provided. No information concerning trends at the other locations was presented.
Conventional parameters were also measured at the Airport location. Levels of pH and total organic
carbon in onsite ground-water monitoring wells were found to be similar to background levels, while
levels of specific conductance and total organic halogens were found to be above background levels
(Reference 5, page 51). Explanations for elevated levels of total organic halogens were not available
(Reference 5, page 51).
Data on concentration of uranium 238, radium 226, and thorium 230 from unspecified studies were
presented in the Hazard Ranking System Scoring Package (Reference 1, pages 73 through 76) (see
Table 6). EPA standards for radium-226 and DOE clean-up criteria for thorium-230 have been
established at 5 pico Curies per gram (pCi/g).
TABLE 6. SURFACE SOIL CONCENTRATION (IN pCilg)
Constituent
Airport
Hazelwood
Futura
Background
Uranium-238
<3 - 1,600
4 - 800
<3 - 2,500
1.0
Radium-226
0.5 - 5,600
0.5 - 700
0.4 - 2,300
0.5
Thorium-230
0.6 - 2,600
1 - 790
<1.1 - 2,000
0.2
Characterization activities at the NPL site were conducted from 1985 to 1987 by DOE. Soils for the
Airport location revealed levels of molybdenum and cobalt, while levels of other metals were not
provided. Soil contamination at the Airport location was found up to 18 feet below the surface;
contamination at the Futura property was found at depths of up to 15 feet; and contamination at the
Hazeiwood Storage area was found at depths of up to 6 feet (Reference 2, pages 12 and 13;
Reference 7, page 10). DOE guidelines for determining thorium-230 and radiuin-226 contamination
is 5 pCi/g (average) for surface soil and 15 pCilg (average) for subsurface samples (Reference 2,
page 12).
7
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St. Louis AirportfHazelwood/Futura
ENVIRONMENTAL DAMAGES AND RISKS
Although contamination of surface water and ground water has been documented, these routes were
not considered in the Hazard Ranking System scoring because of the lack of exposure targets.
Ground water is of poor quality. The nearest well is approximately 1.5 miles north of the Airport
location; its function was not specified (Reference 1, page 45). No uses of Coldwater Creek are
known. The primary exposure route is air due to the emission of radon-222 and the proximity of
people working near the sites (Reference 1, page 45). An estimated 7.5 millirem per year was
determined to be the exposure to the maximally exposed individual from the Airport location. The
DOE radiation protection standard is 100 mihirem per year (Reference 5, pages 41 and 42).
Uses of nearby property are predominantly commercial and industrial. A 24,000-person commercial
building complex is located .25 mile west of the Airport location, while the St. Louis International
Airport facilities are 1 mile south of the Airport location (Reference 1, pages 29 through 30 and 37).
Numerous industrial facilities are within .25 mile of the Airport location. A park is immediately
north of the Airport site. Nearby residential areas include 75 to 100 people living .5 mile west of the
Airport location, 1,500 people living 1 mile northwest of the Airport location, and 8,800 people
residing more than .75 mile north of the Hazelwood and Futura locations in the City of Hazelwood.
Commercial and industrial facilities are located north and east of the St. Louis Airport vicinity
properties and the Hazeiwood and Futura locations (Reference 1, pages 37 and 38).
An estimated 142,000 cubic yards of contaminated media is present in the St. Louis Airport vicinity
properties (Reference 2, page 6). Soil contamination adjacent to the three areas is shown in Figures 2
and 3 (Reference 2, page 17; Reference 7, page 11). DOE guidelines for determining thorium-230
and radium-226 contamination is 5 pCi/g (average) for surface soil and 15 pCi/g (average) for
subsurface samples (Reference 2, page 12).
REMEDIAL ACTIONS AND COSTS
Contaminated material was excavated from the Futura property and placed on the Hazeiwood Storage
area (Reference 1, page 39). This excavation was performed in 1979 (Reference 1, page 6). Offsite
remedial excavation was conducted from 1984 to 1986 near the Hazelwood Storage area, adding
contaminated soil to the Hazelwood Storage area (Reference 7, page 5).
Additional work to be performed at the site includes Remedial Investigation/Feasibility Study
development, Environmental Impact Statement preparation, monitoring, and waste storage. Cost at
the Airport location was estimated at $32 million; at the adjacent Airport properties, it was estimated
8
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I
2.
I
1
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Ul
or mm CONIANINAMON
[;| AIMS OF SIIM'K 111) IONIAN I MA I ION
CH OUIIOINC
PHOPfim BOUNDARY
SO
Si
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Mining Waste NPL Site Summary Report
at $50 million; and at the Latty Avenue properties (which includes the Hazelwood and Futura
properties) it was estimated at $25.5 million. RODs for all areas are scheduled for 1994.
CURRENT STATUS
The Airport, Futura, and Hazelwood areas were added to the NPL in October 1989 (Reference 3,
page 6). The Federal Facilities Agreement was signed in late June and became effective August 17,
1990. DOE is the head agency and will be conducting all investigations and remediation, while EPA
has oversight authority and must approve the final remedial selections. A ROD is scheduled to be
completed in 1994 (Reference 4).
4-. 11
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St. Louis Airport/Hazeiwood/Futura
REFERENCES
1. Hazard Ranking System Scoring Package, St. Louis Airport/Hazeiwood Interim StoragelFutura
Coating Site, St. Louis, Missouri; EPA; June 3, 1988.
2. Site Plan for St. Louis Airport Site and Vicinity Properties, St. Louis, Missouri; Prepared for the
U.S. Department of Energy by Bechtel National, Incorporated; November 1989.
3. Environmental Restoration and Waste Management Site-Specific Plan for Oak Ridge Operations
Office (Formerly Utilized Sites Remedial Action Program, Missouri); Prepared for U.S.
Department of Energy; November 1989.
4. Telephone Communication Concerning the Current Status of the St. Louis Airport Sites; From
Sue McCarter, SAIC, to Gene Gunn, EPA Region VII; December 18, 1990.
5. St. Louis Airport Site Annual Site Environmental Report, St. Louis, Missouri, Calendar Year
1988; Prepared for the U.S. Department of Energy by Bechtel National, Incorporated; April
1989.
6. National Priorities List Summary Sheet for the St. Louis AirportlHazelwood Interim
StoragefFutura Coatings Company Site; EPA; Undated.
7. Site Plan for Latty Avenue Properties, Hazelwood, Missouri; Prepared for the U.S. Department
of Energy by Bechtel National, Incorporated; November 1989.
12
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Mining Waste NPL Site Summary Report
BIBLIOGRAPHY
EPA. Hazard Ranking System Scoring Package, St. Louis Airport/Hazeiwood Interim Storage/Futura
Coating Site, St. Louis, Missouri. June 3, 1988.
EPA. National Priorities List Summary Sheet for the St. Louis Airport/Hazeiwood Interim
StoragefFutura Coatings Company Site. Undated.
McCarter, Sue (SAIC). Telephone Communication Concerning the Current Status of the St. Louis
Airport Sites to Gene Gunn, EPA Region V I I. December 18, 1990.
Prepared for the U.S. Department of Energy by __________. Environmental Restoration and
Waste Management Site-Specific Plan for Oak Ridge Operations Office (Formerly Utilized Sites
Remedial Action Program, Missouri). November 1989.
Prepared for the U.S. Department of Energy by Bechtel National, Incorporated. Site Plan for Laity
Avenue Properties, Hazeiwood, Missouri. November 1989.
Prepared for U.S. Department of Energy by Bechtel National, Incorporated. Site Plan for St. Louis
Airport Site and Vicinity Properties, St. Louis, Missouri. November 1989.
Prepared for the U.S. Department of Energy by Bechtel National, Incorporated. St. Louis Airport
Site Annual Site Environmental Report, St. Louis, Missouri, Calendar Year 1988. April 1989.
13
c i
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St. Louis Airport/Hazeiwood/Futura Mining Waste NPL Site Summary Report
Reference 1
Excerpts From Hazard Ranldng System Scoring Package,
St. Louis Airport/Hazeiwood Interim Storage/Futura Coating Site,
St. Louis, Missouri; EPA; June 3, 1988
-------
MifRE
— . I
-_ . ) 26 October 1988
W52.398
OCT 31 C8
— . — m — — • , -•
rr .r— $ ,
Ms. Shelley Brodie
U.S. Environmental Protection Agency
Region VII
726 Minnesota Avenue
Kansas City, KS 66101
Dear Ms. Brodie:
Enclosed is the QA signed package for St. Louis Airport/Hazeiwood
Interim Storage/Fucura Coating Site, Sc. Louis, Missouri. Please submit
the package, in triplicate, to the EPA Docket Clerk, Ms. Tina Maragousis
at EPA Headquarters and retain the original in your program file. In your
transmittal letter to Ms. Maragousis, please indicate that this site is
being considered for Update 8.
If you have any questions regarding this material, please contact
Barry Nash at (703) 883-5843.
Sincerely,
L. Sue Russell
Group Leader
Hazardous Waste Systems
LSR/flh
Enclosure
cc: S. Crysta].l
J. Kruger
The MITRE Corporation
Civil Systems Dwision
7525 Colshire Drive, McLean. Virgirua 22102-3481
Telephone (703) 883 -6000/Te1 248923
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SITE AGGREGATION RATIONALE
St. Louis Airport, Hazeiwood Interim Storage, and Futura Sites
St. Louis County, Missouri
The St. Louis Airport (SLAP) Site and the Latty Avenue properties consisting of
the Hazelwood Interim Storage (HIS) Site and the Futura Coatings (FUTURA) Site
are located near the Lambert St. Louis International Airport. These sites were used
for storing radioactive by-product wastes and other wastes resulting from the
activities of the Manhattan Engineering District ( D) under the jurisdiction of
the U.S. Army, and the U.S. Atomic Energy Commission (AEC). The responsibility
for management of these wastes was ultimately transferred to the U.S. Department
of Energy (DOE) in 1977. All three sites are under investigation through DOE’s
Formerly Utilized Sites Remedial Action Program. (FUSRAP) (Reference 2, P. 1).
The St. Louis Airport Site and the Latty Avenue properties are presented in this
HRS package as one aggregated site. The aggregation of these three sites is based
on several factors, including the close proximity of all three sites, the storage at
each site of radioactive wastes from the same waste source, detected radioactive
contamination along roads used to transport the wastes between the sites, similar
threats posed by the contaminants from all three sites on the same surface water
and groundwater resources, similar threats of air releases posed by contaminants at
all three sites, and the historical involvement of the U.S. Department of Energy in
the management of wastes at each of these sites (Reference 20). Details pertaining
to the location and history of each Site and the rationale for aggregation of the
sites are presented in the following paragraphs.
The SLAP, HIS, and FUTURA Sites are located within approximately one-half
mile of one another, as shown on Figure 1. The SLAP Site is the largest of the
three sites (21.7 acres) and is located immediately north of the Lambert St. Louis
-------
Additional wastes stored at the HIS and FUTTJRA Sites were moved to the West
Lake Landfill in Sc. Louis County at an unknown date (Reference 1).
Radiological surveys of the Latty Avenue properties by the Nuclear Regulatory
Commission (NRC) in 1976 and the Oak Ridge National Laboratory (ORNL) in
1977 disclosed the presence of Uranium, Thorium and Radium in on-site buildings.
In addition, detected concentrations of these contaminants in soil exceeded NRC
and DOE guidelines for a release from unrestricted land areas (Reference 1,
Reference 2 P. 17). Cleanup actions at these sites by the property owner resulted
in the generation of approximately 13,000 cubic yards of radioactive material
This material was placed on the HIS Site to form the main storage pile. Remedial
actions in 1984 resulted in the excavation of an additional 14,000 cubic yards of
contaminated soil from the Lacty Avenue properties (Reference 1). This material
was formed into the secondary storage pile at the HIS Site. Both of these storage
piles have remained on the HIS Site to date.
Radiological and/or chemical characterization studies have been performed at all
three sites. These studies indicated that a significant volume of the remaining
surface and subsurface soils at each site contain elevated concentrations of
radioactive contaminants (Reference 2, p. 18). A radiological survey in 1985 of
roads used for transporting the contaminated wastes from the SLAP Site to the HIS
and FUTLJR.A Sites, indicated elevated levels of radioactive contaminants along
Latty Avenue, which forms the northern boundary of the HIS and FUTURA Sites.
As a result, the roads between the SLAP Site and the HIS and FUTIJRA Sites
which were used for transporting the contaminated wastes were designated for
remedial action under DOE’s FUSRAP in 1986 (Reference 3, p. 3). Subsequent to
this designation, Thorium -230 was detected at concentrations as high as 600 pico
.-
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NARRATIVE SUMMARY
St. Louis Airport, Hazeiwood Interim Storage, and Futura Sites
St. Louis County, Missouri
The St. Louis Airport (SLAP) Site and the Latty Avenue properties consisting of
the Hazelwood Interim Storage (HIS) Site and the Futura Coatings (FUTURA) Site
are located near the Lambert St. Louis International Airport. These sites were used
for storing radioactive by-product wastes and other wastes resulting from a U S.
Department of Energy (DOE) uranium processing operation. All three sites are
under investigation through DOE’s Formerly Utilized Sites Remedial Action
Program (FUSRAP).
The St. Louis Airport Site and the Latty Avenue properties are presented in this
HRS package as one aggregated site. The aggregation of these three sites is based
on several factors, including the close proximity of all three sites, the sto age at
each site of radioactive wastes from the same waste source , detected radioactive
contamination along roads used to transport the wastes between the sites, similar
threats posed by the contaminants from all three sites on the same surface water
and groundwater resources, similar threats of air releases posed by contaminants at
all three Sites, and the historical involvement of the U.S. Department of Energy in
the management of wastes at each of these sites. Details pertaining to the locations
of the Sites and the history of radioactive waste disposal at these sites are provided
in the following paragraphs.
The SLAP, HIS, and FUTURA Sites are located within approximately one-half
mile of one another, as shown on Figure 1. The SLAP Site is the largest of the
three sites (21.7 acres) and is located immediately north of the Lambert St. Louis
International Airport. The SLAP Site is bounded by the Norfolk and Western
Railroad on the south, Coidwater Creek on the west, and McDonnell Boulevard on
c i
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Figure 1.
I Ocitt ion ol thi. . SI.AP, HIS ind FUTIJRA s teF.
Reference 2.
W [ I I [ RAIJ
CROCLI1 CO.
MRA1
MOlOfiS
‘I
I i
I
I
flANSp E ROAD
LAIJEIFRI - SI. 10 1115 INTEHUA1IONAI AIRI 1 OAI
O f to g*it
-------
the north and east. The McDonnell Douglas Corporation is adjacent to the SLAP
Site on the west and southwest. The office buildings of this company are within
one-half mile of contaminated surface soil at the SLAP Site. Twenty four
thousand employees of this company work at the location adjacent to the SLAP
Site. The Latty Avenue properties, consisting of the adjoining HIS Site and the
FUTURA Site, span 11 acres along Latty Avenue in Hazeiwood, Missouri, as shown
on Figure 2. This area is bounded on the north by Laity Avenue, on the east by
the Hazeiwood city limit, on the west by the Norfolk and Western Railroad and on
the south by a tributary to Coldwater Creek.
Wastes from uranium processing operations were stored on the open ground at the
SLAP Site from 1947 until 1967. These wastes included: pitchblende raffinate,
radium-bearing residues, barium sulfate cake residues, Colorado raffinate residues,
used dolomite liner and recycled magnesium fluoride liner generated as slag, and
uranium containing sand and scrap metals. In 1957, contaminated scrap metal and
miscellaneous radioactive materials were buried in the western end of the property.
In 1966 and 1967, most of the wastes stored at the SLAP Site were transported to
the Latty Avenue properties (HIS and FUTUR.A Sites). In 1969, the St. Louis
Airport Authority initiated partial remediation of the SLAP Site. At that time, the
remaining barium sulfate waste was transported to the Laity Avenue properties
-and all structures except a security fence were buried on-site. From 1967 to 1973,
a portion of the wastes which were previously transported from the SLAP Site to
the HIS and FUTUR .A Sites was shipped to the Cotter Corporation in Canon City.
Colorado. Additional wastes stored at the HIS and FUTURA Sites were moved to
the West Lake Landfill in St. Louis County at an unknown date (Reference 1).
Cleanup actions by the owner of Laity Avenue properties resulted in the
generation of approximately 13,000 cubic yards of radioactive material. This
‘7
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HAZELW000
BERKELEy
Boundaries of the HIS
Reference 9, page 6.
and PUTURA sites.
TO
COLDWATEM
I
WAGN1
£LfCT iC CORP
DECON FACfljTy
(TEMPO ARYI
GENERAL $NVESTMPIIT FUPaØ
EA&. ESTATE COMPANY
SUPPLEMENTARY
STORAGE PILE
SiTE
MAIN
STORAGE
PILE
NO SCALE
HAZELWOOD
BERKELEY
1.)
Figure 2.
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2. WASTE CHARACTERISTICS
Reactivity and IncornDatibilitv
Most reactive compound:
Radioactive residues present on all three subsites are believed to be
relatively stable. It is not known whether the intermixing of these residues
poses a threat of a fire or explosion.
SCORE - 0
Most incompatible pair of compounds:
None found
Toxicity
Most toxic compound:
Uranium (Reference I page 2711).
SCORE - 9
Hazardous Waste Ouantitv
Total quantity of hazardous substances at the site (Give a reasonable estimate even
if quantity is above maximum):
At least 4,100 tons of hazardous wastes were deposited at the SLAP Site, as
documented below:
SCORE - 8
Basis of estimating and/or computing waste quantity:
Basis of Computing Waste Quantity
(Reference 8, p. 7; and Reference 16, pp. 2-1 and 2.4)
Waste Material Ouantitv *
(1) Contaminated steel and alloy 3,500 tons
scrap.
(2) Drums containing miscellaneous 600 tons
residues, Japanese uranium con-
taining sand, and contaminated
scrap metal.
(3) 50 to 60 truckloads of contaminated
metal scrap, not calculated because
of lack of data.
TOTAL 4,100 tons
* Note: All quantities were converted to tons using the conversion factors given in
reference 17, p. 19.
6
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3. TARGETS
PoDulatlon Within 4-Mile Radius
Circle radius used, give population, and indicate how determined:
0 to 4 mi 0 to 1 mi 2mi 0 to 1/4 mi
The McDonnell Douglas Corporation borders the SLAP Site on the west and
southwest (Reference 16, p. 3-20). The office buildings of this company are
within one-half mile of contaminated surface soil on the SLAP Site
(Reference 16, pp. 3-19 and 3-27). Twenty four thousand employees (24,000)
of this company work at the location adjacent to the SLAP Site (Reference
19).
SCORE - 27
Distance to a Sensitive Environment
Distance to 5-acre (minimum) coastal wetland, if 2 miles or less:
No coastal wetlands exist within two miles of the site.
SCORE - 0
Distance to S-acre (minimum) fresh-water wetland, if I mile or less:
No fresh-water wetlands are known to exist within one mile of the site
(Reference 16, pp. 1-2 and 3-18; and Reference 22).
SCORE - 0
Distance to critical habitat of an endangered species or national wildlife refuge, if
I mile or less:
No critical habitat areas are known to exist within one mile of the site
(Reference 16, pp. 1-2, 3-17, and 3-18).
SCORE - 0
7
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Land Use
Distance to commercial/industrial area, if 1 mile r less:
The McDonnell Douglas Corporation borders the SLAP Site to the west and
the southwest (Reference 16, p. 3.20). Thus, the distance to an industrial
area is less than one-fourth mile.
SCORE - 3
Distance to national or state park, forest, or wildlife reserve, if 2 miles or less:
No national or state park, forest, or wildlife reserve is known to exist
within two miles of the Site (Reference 22).
Distance to residential area, if 2 miles or less:
The nearest residential area is in Hazelwood, one-half mile from the SLAP
Site. This area of Hazelwood has 75 to 100 residents (Reference 16, p. 3-20).
Distance to agricultural land in production within past 5 years, if 1 mile or Iess
No agricultural land is known to exist within one mile of the site
(Reference 16, pp. 3-18, 3-19, and 3-20). -
Distance to prime agricultural land in production within past 5 years, if 2 miles or
less:
No agricultural land is known to exist within one mile of the site
(Reference 16, pp. 3-18, 3-19, and 3-20).
Is a historic or landmark site (National Register of Historic Places and
National Natural Landmarks) within view of the site?
There are no archaeological or historical sites or districts which are
included in the National Register of Historic Places within one mile of the
site (Reference 16, p. 3-21). -
8
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.4-
River. Both the quantity and quality of flow in Coidwater Creek are influenced by
surface water runoff from adjacent developed areas (e.g., the airport and industrial
and residential areas) and industrial and municipal discharges; there are no known
uses of the flow in the creek. Groundwater in the vicinities of the sites is of very
poor quality (saline), and the yields from water wells in the local limestones are
very low. Consequently, groundwater is not generally used in the area around the
sites. Water from the Missouri and Mississippi Rivers is treated to meet the area’s
water needs; the closest water treatment facility is on the Missouri River upstream
of its confluence with Coldwater Creek. There are no records of any producitig
water wells within a 1-mile radius of the SLAP Site with the nearest water well
being approximately 1.5 miles north of the SLAP Site (Reference 3, pp 1-1, 1-2, 3-6
through 3-13, Reference 6, pp. 1, 4).
The observed release of Rn-222 from the SLAP and HIS Sites may present a
potential hazard to the population located within the vicinity of the sites. Seventy.
five to 100 people reside in an industrially zoned area of Hazelwood approximately
0.5 mile west of the SLAP Site, and approximately 1,500 people reside along Chapel
Ridge Drive one mile northwest of the SLAP Site (Reference 3, p. 3-20) The
McDonnell Douglas Corporation employs 24,000 people adjacent to the SLAP Site
(Reference 7), and Ford Motors maintains a large facility approximately 0.5 mile
north of the site. The Lambert-St. Louis International Airport facilities are
approximately one mile south of the SLAP Site. Recreational programs are
conducted at Berkeley Khoury League Park immediately north of the SLAP Site,
and numerous other industrial facilities are located within 0.25 mile of the site
(Reference 3, pp. 3-18 through 3-21). Residential areas nearest the HIS and
FUTTJRA Sites are approximately 0.3 mile to the west in Hazelwood; most of
Hazelwood’s residents (1980 population of 8,819) are north of Interstate Highway
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-5.
270 approximately 0.75 mile north of the HIS and FTJTURA Sites (Reference 3, p. 3.
20; Reference 6, P. 4). Residences in the city of Berkeley (1980 population of
16,146) are southeast of the site. Commercial and industrial facilities are adjacent
to the HIS and FUTURA Sites to the north and east (Reference 3, p. 3-19; Reference
6, p. 3).
2. INFORMATION ON CONSTITUENTS OF WASTE
Ouantitv
All of the contaminants evaluated at the SLAP, HIS and FtJTURA Sites were
constituents, or are decay products of the constituents, of the radioactive wastes
that were stored at the sites. The radioactive wastes stored at the sites wire the
result of uranium processing operations (Reference 5, pp. 2, 3; Reference 2, pp 2, 3.
5) and, therefore, are special study wastes under Section 3001 (b)(3)(A)(ii) of the
RCRA. Consequently, all wastes at the sites are special study wastes, and all
potential environmental hazards are due to special study wastes.
A total of 125,150 tons of radioactive wastes were stored at the SLAP Site; this total
included 106,500 tons of raffinates, 10,200 tons of leached and unleached barium
sulfate cake, 4,000 tons of liner slag, 350 tons of miscellaneous residues (Reference
8, p. 32). 3,500 tons of contaminated scrap metal, and 600 tons (2,400 drums) of
uranium bearing sand, contaminated scrap materials, and miscellaneous residues.
An unknown quantity (50 to 60 truckloads) of contaminated scrap metal and
possibly contaminated structure s were also buried at the site (Reference 3, pp. 2-1.
2-4). The quantity of wastes that was moved to the HIS and FUTITRA Sites cannot
be determined from existing documents; consequently, the quantities of wastes still
remaining at the SLAP, HIS and FUTURA Sites are unknown. The original storage
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‘I-
-6-
pile at the HIS Site contains approximately 13,000 tons (cubic yards) of
contaminated materials that were excavated during remediation of the adjacent
FTJTTJRA Site (Reference 2, p. 7). The 4,100 tons of special study (radioactive)
wastes used for scoring purposes received the maximum hazardous waste quantity
factor score of 8 in the HRS scoring.
Concentration
The concentrations of radionuclides in the radioactive wastes originally stored at
the SLAP Site are unknown. An inventory of these wastes estimated that the
121,050 tons of raffinates, barium sulfate cake, liner slag, and miscellaneous
residues contained approximately 241 tons of uranium (Reference 8, p. 32).
Radiological characterizations of the SLAP, HIS and FUTURA Sites in 1977 and
1986 indicated that Ra-226, Th-230, and U-238 are the major radioactive
contaminants at the sites. The ranges in concentrations of these radionuclides in
soil, groundwater, surface water, stream sediment, and air samples from the sites are
provided in Tables 1 through 5.
Reactivity and Incomoatjbjljty
Radioactive residues present on.site are believed to be relatively stable. It is not
known whether the intermixing of these residues would pose a threat of a
fire/explosive hazard. Therefore, the special study wastes received a reactivity
factor score of 0.
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-7-
Table I
Radlonucilde Conceotratlous In SLAP, HIS and FUTURA Soil Samples
Concentration Range In Soil Sam pies
SLAP Sit. HIS Sit. YUTUIU, Sat. Background
Rsthonuci d. (pCi/ c) 5 (pCi/g)b ( p C / 1 )C (pC a/ g )”
Rs-226 OSlo 5,620 05 to 700 OSlo 2300 0.5
Th-230 0.6 to 2,600 0.1 to 790 0.2 to 2000 0.2
U -238 c3to l,60 0 41*300 10 1o25 00 10
5 Raf .r.uc. 5, pp. 19, 21. PacoCw ’i.s psi ps = pCi/g.
b Raf.r.nc. 2, pp. 16, 19, 42 througla ST PicoCw ’t.. p .r grain = pC i ! g
C Ref.rsnc. 9 PicoCun p .r gram = pCs/g.
d for hi St. Lows, Mia.oura, u .s.
Table 2
Radionuclide Conceatrationg In SLAP, HIS and FUTIJRA Groundwater Samplesa
Concentration Range In Groundwater Samples
SLAP Sat. HIS Sit. FV’?UR& Sit.
Rad aonue id. ( p C / )b (pCi/If (,Ci/I)d
Rs.226 0.2 to 0.5 0.1 to 0.7 06 to 1.3
Th-23o 0.2 to 1.2 0.6 to 2.6 0.1 to 0.4
Total uranuun 16 to 6,170 <3 to 33 <3.0 to 6.0
5 Bsckground ridionuclid. concontrations an C usdvos.r win sos provid.d In neferonc. doc os. for ks SLAP, HIS and
PUTURA Sat.
b • .nscai pp. 21, 22. PlcoCufls pin list • pC i/I.
C Rafsr.nc. 6, pp. 22, 23, PacoCura.. pin Ills, — pCi/I.
d f 10. PicoCui .s psi tat., pCI/I.
TotsI ura iu ii U-234 and U-Us coabis.d.
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Table 3
Radionuclide Concentrations In SLAP and HIS Surface Water Samples
Concentration Range in Surface Water Samples
SLAP Sit. HIS Sit. Background
R.a.d ionuchd. (pCi/i)’ (pCi/l)b (pCl/i) .b.c
R a.226 0 1 tO 0.4 0.1 to 0.4 0.2 to OS
Tb.2S0 <0OS t o0.5 <0.1101.0 <021002
Total uranium
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-9-
Table S
Radon-222 Concentrations In SLAP and HIS Air Samples
Concentration Range In Air Samples
SLAP Site SLAP Av.re. s HIS Sit. HIS Avsn e
(pCi/I)’ (pCi/l)1 b (pCI/l)$ C (pC&/l)
Olto6$ 04to35 0.ltoS4 02so1$
PicoCuriss per lis.r pCi/i All conc.ntrstiona include the bckround Rn-lU concentration of 0.3 pCi/I
b Reference 1, pp 14, 15. 16
e Reference 6, pp 14. 15, 16
Toxicity
The toxic components of the special study wastes include Ra-226, Rn-222, T.h-230,
and U-238. Ra-226 is a highly radiotoxic element, and inhalation, ingestion, or
bodily exposure to Ra-226 can result in lung or bone cancer and skin damage The
chief hazard from Rn-222 is inhalation of the gaseous element and its solid
daughters (decay products) that are attached to particulates in the air Once
inhaled, the solid radon daughters attach to the lungs and then decay, transmitting
energy (radiation) to the lungs. Inhalation or radon has been considered to be a
major cause of the high incidence of lung cancer in uranium miners. On an acute
basis, Th-230 has caused dermatitis; however, taken internally as thorium oxide, it
has proven to be carcinogenic due to its radioactivity. U-238 is a highly toxic
element on an acute basis. Permissible levels for soluble uranium compounds are
based on chemical toxicity while the permissible body level for insoluble uranium
compounds is based on radiotoxicity. The high chemical toxicity of uranium and its
salts is largely shown in kidney damage, and the high toxicity effect of insoluble
uranium compounds is largely due to lung irradiation by inhaled particles
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-10-
(Reference 11, PP. 2357, 2577, 2711). Due to the toxicitjes of the radjonuclides in
the special study wastes, the special study wastes received the maximum toxicity
factor score of 9.
The concentrations of Ra-226 and Th-230 in surface and subsurface soils at the
SLAP, HIS and FUTIJRA Sites greatly exceed the DOE’s soil (land) guidelines or
maximum limits for unrestricted use; these guidelines for radionuclides (Ra-226, Ra-
228, Th.230, and Th-232) are S pCi/g averaged over the first 15 centimeters of soil
below the surface and 15 pCi/g when averaged over any 15-centimeter thick soil
layer below the surface (Reference 5, P. 24). Individual and average concentrations
of Rn-222 in air samples from the SLAP Site exceed the maximum permissible
concentration (MPC) of 3.0 pCi/i for air in unrestricted areas as promulgated by the
U.S. Nuclear Regulatory Commission (NRC) in Title 10, Code of Federal
Regulations, Part 20 (10 CFR 20). The concentration of radionuclides in
groundwater and surface water at the SLAP, HIS, and FUTT.JRA Sites are within
the standards and guidelines promulgated by the NRC in 10 CFR 20 and the EPA in
40 CFR 141 (Primary Drinking Water Standards)(Reference 12, p. 4-3).
3. EXPOSURE INFORMATION
- Releases
At the present time, contaminants can leach from the SLAP, HIS and FUTtJRA
Sites into groundwater. This type of release is confirmed by the concentrations of
radionuclides in on-site monitoring wells (Table 2). Groundwater samples collected
at the SLAP Site in 19*6 contained average concentrations ranging from 0.2 to 0.5
picoCuries per liter (pCi/I) for Ra-226, 0.2 to 1.2 pCi/ I for Th-230, and 16 to 6,570
pCi/i for total uranium (U.234 and U-238 combined) (Reference 1, pp. 21, 22).
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—11—
Groundwater samples collected at the HIS Site in 1986 contained maximum average
concentrations of Ra-226, Th.230, and total uranium of 0.7, 2.6, and 33 pCi/i,
respectively (Reference 6, pp. 22, 23).
As shown in Table 1, soils at the SLAP, HIS, and FUTURA Sites contain
concentrations of radionuclides that exceed background soil con ntrations
Therefore, surface runoff from the sites could transport contaminants to Coidwater
Creek by direct overland flow or in drainage ditches adjacent to the sites. Surface
water samples collected in 1986 at locations downstream of the sites had average
concentrations of Ra-226, Th-230, and total uranium that exceeded background
concentrations in samples collected upstream of the sites (Table 3) Analyses of
sediment samples collected at surface water sampling locations produced similar
results at both sites (Table 4) and indicated Th-230 contamination at concent ations
much greater than background in a drainage ditch north and downstream of the HIS
and FUTURA Sites (Reference 6, pp. 20, 22, 24, 25). The direction of groundwater
flow at all three sites is toward Coidwater Creek, and groundwater may discharge
into the creek allowing contaminants to enter surface water. The surface water
monitoring at both sites indicates that this potential contamination mechanism has
not affected surface water quality at the sites (Reference 1, pp. 19, 21; Reference 6.
p. 19).
A statistical analysis of Rn-222 data in the MRS scoring package (Reference 12)
confirmed an observed air release at the SLAP Site. Rn-222 is constantly being
emitted as a radioactive decay product of the Ra-226 present at both sites. Air
monitoring at the SLAP Site during 1986 revealed annual avera Rn•222
concentrations of 0.4 to 3.5 pCi/I (Table 5). Annual average Rn-222 comntrations
at the HIS Site during the same time period were 0.2 to 1.8 pCi/ I (Table 5) The
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‘to’
12-
annual average Rn-222 Concentrations at both sites include the approximate
background Rn-222 concentration of 0.3 to 0.5 pCi/I (Reference 6, pp. 14, 15, 16;
Refereace 1, p. 14; Reference 12). The special study wastes received the maximum
observed air release factor score of 45.
Exnosures
The groundwater and surface water routes are not primary routes of exposure for
the SLAP. HIS and FTJTTJRA Sites. The groundwater in the area of the sites is of
very poor quality, and water well yields are very low. There are no known uses of
the flow in Coidwater Creek (Reference 3, pp. 1-1, 1-2, 3-6 through 3-13; Reference
6, pp. 1, 4). However, one report (Reference 3, pp. 3-6) indicates that there is a
potential water well approximately 1.5 miles north of the SLAP Site. Thus.
groundwater is a potential exposure route. The use of this well is not known.
Although water is withdrawn from the Missouri and Mississippi Rivers for
municipal drinking water, the closest withdrawal points (treatment plants) are on
the Missouri River upstream of the Coldwater Creek confluence and on the
Mississippi River more than 3 miles downstream of the SLAP, HIS and FUTURA
Sites (Reference 3, p. 3-9; Reference I, p. 5). Due to the lack of targets, th-
groundwater and surface water routes were not evaluated in the HRS scoring
package.
The air route is the primary exposure route for the SLAP, HIS and FUTURA Sites
due to the constant emission of Ra-222 from the decay of the Ra-226 at the sites.
This exposure route has the potential to affect people residing and working in the
vicinity of the sites. There are numerous residences in the cities of Hazeiwood and
Berkeley within 4 miles of the sites, and several small to large, industrial and
commercial facilities are adjacent to and in close proximity to the sites (Reference
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-13-
3, pp 3-18 through 3-21; Reference 6, PP. 3, 4). Based on the employment of 24,000
people at the McDonnell Douglas Corporation within 0.5 mile of the SLAP Site
(Reference 7), the special study wastes received a population within 4-mile radius
factor score of 27. The special study wastes received the maximum land use factor
score of 3 because commercial and industrial facilities are immediately adjacent to
all three sites.
4. HAZARD TO HUMAN HEALTH AND THE ENVIRONMENT
The SLAP, HIS and FUTURA Sites present a threat to human health and the
environment. Radioactive wastes from uranium processing operations, designated as
special study wastes in Section 300l(b)(3)(A)(ii) of the RCRA, were stored at the
sites. Most of these radioactive wastes have been removed from the sites, but
radionuclides from the wastes (i.e., Ra-226, Th-230, and U-238) have been detected
in surface and subsurface soils, groundwater, surface water, and stream sediments.
Radon gas (Rn-222) from the decay of Ra-226 at the sites is constantly being
released into the air. The concentrations of Ra-226 and Th-230 in surface and
subsurface soils at the SLAP, HIS and FUTURA Sites are as much as 1,124 times
greater than the DOE’s soil guidelines for unrestricted use, and concentrations of
Rn-222 in air samples from the SLAP and HIS Sites are one to two times greater
than the DOE’S concentration guide for uncontrolled areas and the NRC’s MPC for
restricted areas. Groundwater and surface water are generally not used in the area
of the sites; however, more than 24,000 people work within 0.5 mile of the sites, and
there are numerous residences and commercial and industrial facilities within 4
miles of the sites. Residents and employees in the vicinities of the Sites could be
exposed to the carcinogenic radon gas.
1\
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‘I
.14.
S. SUMMARY
Radioactive wastes from uranium processing operations were stored at the SLAP,
HIS and FUTURA Sites; these wastes were designated as special study wastes by
RCRA. In accordance with the SARA and EPA directives, this evaluation was
prepared to determine to what extent these special study wastes affected the HRS
score for the sites. Toxic radionuclides from the special study wastes have been
released to groundwater, surface water, and air. Human exposure to the
contaminated waters is not likely, but a large population adjacent and in close
proximity to the sites could be exposed to radon gas that is constantly released into
the air from the decay of radionuclides at the sites. Therefore, the sites present a
threat to human health and the environment due to the presence of the special Study
wastes. The HRS score for the sites was based solely on the special study waSt s.
6. REFERENCES
References from MRS Scorina Packaae
All references cited in the documentation record for the HRS scoring package were
reviewed for this evaluation. The references from the HRS scoring package tha
were cited in this evaluation are as follows:
1. St. Lpuj Air prt Site. Annual Site Environmental Re prt. St. Louis. Missouri.
Calendar Year 1986 . DOE/OR/20722.145, prepared by Bechtel National, Inc.,
Oak Ridge, Tennessee, for the U.S. Department of Energy, Formerly Utilized
Sites Remedial Action Program (FUSRAP), Oak Ridge Operations Office, Oak
Ridge, Tennessee, May 1987.
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-15-
2. Characterization ReDort for the Mazeiwood Interim Stornie Site. Hazeiwood.
Missouri . DOE/OR/20722-141, prepared by Bechtel National, Inc., Oak Ridge,
Tennessee, for the U.S. Department of Energy, Formerly Utilized Sites
Remedial Action Program (FUSRAP), Oak Ridge Operations Office, Oak Ridge,
Tennessee, June, 1987.
3. Draft Report, Environmental Impact Assessment of the Former Airport Storage
Site of the Atomic Energy Commission, St. Louis County, Missouri, prepared by
Roy F. Weston, Inc., Westchester, Pennsylvania, for Oak Ridge National
Laboratory Nuclear Division, Union Carbide, Oak Ridge, Tennessee, October
1978.
4. Avel, Andy, U.S. Department of Energy, UAttachment 1, Outdoor .adon
Monitoring, personal communication to John Chen, U.S. Environmental
Protection Agency, dated September 30, 1987.
5. Radioloaical and Limited Chemical Characterization Renort for the St Louis
Air ort Site. St. Louis. Missouri . DOE/OR/20722-163, prepared by Bechtel
National, Inc., Oak Ridge, Tennessee, for the U.S. Department of Energy,
Formerly Utilized Sites Remedial Action Program (FUSRAP), Oak Ridge
Operations Office, Oak Ridge, Tennessee, August 1987.
6. Hazelwood Interim Storane Site. Annual Site Environmental Renort. Hazeiwood.
MlssourL Calendar Year 1986 . DOE/OR/20722-143, prepared by Bechtel
National, Inc., Oak Ridge, Tennessee, for the U.S. Department of Energy,
Formerly Utilized Sites Remedial Action Program (FUSRAP), Oak Ridge
Operations Office, Oak Ridge, Tennessee, June 1987.
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16.
7. Copeland, Joe, McDonnell Douglas Corpora jo St. Louis, Mi o rj, persona!
communication to Jill Biesma, Jacobs Engineering Group Inc., Leneza, Kansas.
dated November 9, 1987.
8. Radiplpajcpl Survey f the St. Lpui Airport Storpi Site. St. Louj . Misspuçj
Seotember 1979. Final Rep 1 , DOE/EV.0005/l6, prepared by Oak Ridge
National Laboratory, Oak Ridge, Tennessee, for the Formerly Utilized
? D/AEc Sites Remedial Action Program, U.S. Departme of Energy,
Assistant Secretary for Environment, Divj io of Envjropmentai Controi
Technology, Washington, D.C.
9. Radjplo2jCpI Chprppterjzptipn Report For The Fu jrp Cpptj 5 S 11
DQE/OR/20722.1sg prepared by Bechtel National, Inc., Oak Ridge, Tennessee
for the U.S. Department of Energy, Formerly Utilized Sites Remedial Action
Program (FTJRSAP), Oak Ridge, Tennessee, July 1987.
10. Summary of Radiological Data For SLAP, HIS and FUTTJRA Sites.
11. Sax, N. Irving, Din erpu 5 Proney,je 5 of Indunrjp l Materials. Sixth Editip . Van
Nostrand Reinhold Company, New York, New York, 1984.
12. Biesma, Jill, Observed Air Release Statistical Analysis, Hazard Ranking System
(lIRS) Scoring for the St. Louis Airport and HaZCJwood Interim Storage Sites.
St. Louis County, Missouri, Jacobs Engineering Group Inc., Lenexa, Kansas.
June 3, 198*.
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U•23 8
Th-232
Tb-230
Ra-226
Pb•2 10
4.0-1600
<0.5
0.6.2600
0.5-5600
no dati
16-6570
<0.2-1.2
0.3-0.5
BIcktrourtd
1.0
0.4
0.2
0.5
1.0
SUMMARY OF RADIOLOGICAL DATA
FOR SLAPS, HISS AND PUTIJRA.
ST. LOUIS AIRPORT SITE (SLAPS)
OwDeribip: DOE purchi e from ST. Louis Airport Authority
Statu: of Site Ch*rICt.tIZ*tIOD: Chemicaj and hydro1ogjc charaeterjut; 00 in
progress. Radi I gj characterju an complete.
Gamma Expoiuy, Rat.E 9-261 mictoR/br along the northern Site boundary with a
mean of 84 microR/hr. No other dati presented.
Alrbor e CoacentiatlonE Annual radon ConeentyatjO , ranged from 0.4.3.5 pCi/I.
- The average radon concentration of 0.95 pCi/i u above the single estimate of
background levels of 0.45 pCi/I. No gross tipha or air partic tat data presc cd.
Surfac. and Groundwater Radionuclide concentratj , in pCi/I from 16 on•sjte
monitoring veils and a single Coidwater Creek Station are as foliows
r Creek WelJj
Natural uranium 4.3
Th-230 <0.2
Ra-226 <0.2
Background water concentration data are not presented.
Soil CoaeentratIonE Ranged from baekgroun to CoQcCfltf$tjO greatly ezccedthg
EPA standards for Ra-226 and DOE cleanup criteria for Th-232 and Th230.
Cle3nup criteria and EPA standard are as foijewE
EPA standard Ra.226 S pCi/g surface,
pCi/g subsurface
DOE guideLines Th-232, Th-230 same as for Ra-226
Concentration ranges are as follows
‘I’
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2
Depths of contamination ranged from the surface to 11 fee: with an average depth
of six fee:.
General Comments:
o Sufficient saples from 102 borehole across the 21.7 acres site have bee:
collected and archived. However, additional saple analyses are needed to
adequately determine average concentrations and characterize the source
term as a function of depth.
o Soil concentrations arc highly variable with depth and greatly exceed Ra .226 and
Th-230 cleanup criteria. No U-231 guideline has been developed.
o Elevated radon concentrations greater than 3pCi/l exist at some boundary
locations and background radon concentrations are not well established.
FUTURA SITE
Owacrahip: Jarboc Realty and Investment Company
Status of Site Characterlzatlon: No chemical characterization. Rad iologtcal
characterization is complete.
Gamma Exposure Rate.: 8-27 microR/hr outside existing structures. The
background exposure rate is micro R/hr.
Airborne Cancentratlons: Radon 0.3.0.7 pCi/I inside buildings. Background radon is
limited to one measurement (0.4 pCi/I). Gross alpha concentrations inside buildings
ranged from 0.001-0.004 pCi/m . Removable contamination on building surfa :t
was minimal and below DOE guidelines.
Surtace and Groundwater. Radionuclide concentrations (pCi/I) in Coldwater Creek
and from on si:e monitoring wells arc as follows:
Creek Wells
Natural uranium 4.0 4.0-6.0
Th .230 0.2-0.4 0.1.0.4
R.a-226 0.3 0.6-1.3
Background water COncentration data are not presented.
SoIl Concutratlonr Ranged from background to concentrations greatly exceeding
EPA standards for Ra .226 and DOE cleanup criteria for Th .232 and Th-230. Soil
concentration ranges in pCi/i are as follows:
I , ,
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3
C - it Baekrrrn,nd
U-23$ <3.0-2500 1.0
Th-232 ‘cLO-26 0 .4
Tb-230 <1.1-2000 0.2
Ra-226 0.4-2300 0.5
Pb-210 no data i.o
Dcptht of contamination ranged from the surface to more than 15 feet. No Pb-210
or P0-2 10 data were presented.
General Comm.ntz
o Airborne COflCentration , gamma exposure rates and water concentratjo all
appear to be well below appropriate standards and guidelines.
0 Soil Concentratie are quite variable with depth and can greatly exc: d
limits for Ra -226 and guidelines for Th-230. Th•232 cOncentrations are not
significantly above background. No U-238 guideline has been developed.
0 Potential impacts to Coldwat r Creek need to be investigated by sampling
sediments adjacent to the FUTURA/HLSS Complex.
o Additional work needs to be completed to further establish background
radionucljdc COOCentration for radon and w&tcr.
}IAZEL WOOD INTERIM STORAGE SITE (HISS)
Ownership: Leased to Fucura Coating, Inc.
Status of Cbaract.rIzttlea: No chemical characterization sad incon plete
radiological characterization.
Gamma Exposure Rate: 13-55 m.icroftfhr with a ean of 24 microR/hr. Background
exposure is $ microR/hr.
Airborne Concentration: Radon ranged from 0.3-2.2 pCi/I in 1984, 0.3-0.7 pCi/I in
1985 and 0.2-1.8 pCi/i in 1986. Background radon was determined to be 0.5 pCi/i in
1983 and 0.3 pCi/I in 1986.
Surfac, and Cro,ndwater Ridionuclide concentration ranges (pCi/I) from four on-
site monitoring veils and tour surface water stations were as follows:
--
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4
Surface Gr indwater
Natural uranium ‘c3.0 4.33
Th•230 .‘cO.1.O.4 1-2.6
Ra-2.26 0.2 0.3-0.7
There is no apparent effect of surface runoff from the site on surface waters of
Coldwatcr Creek. Uranium concentrations in surface waters by HISS have deelincd
since partial remedial action in 1984.
Soil Conc.ntyatlont Radionuclide concentrations ranged from background to above
EPA standards and DOE guidelines in pCi/g u follow
On-!ite Paekçro
TJ .238 4.0.800 1.0
Th-232 0.7.5.0 0.4
Th-230 1.0-790 0.2
Ra-226 0.5-700 0.5
Pb-210 no data 1.0
Depths of Ra-226 ranged for the surface to six feet with a mean depth of three feeL
There is evidence that Th-230 is more mobile with concentrations as deep as ten
feet. Background Ra•226 concentrations were observed at four feet.
General Co=ments
o Additional fl-230 analyses of archived samples are needed to ade uate1y
deterine the Th-230 content as a function of depth.
o Adjacent properties need to be characterized to determine extent of off•site
contamination along Coidwater Creek and Laity Avenue.
o -Investigation of waste materials sent to the West Lake Landfill needs to be
conducted.
o The main and supplementary waste storage piles need to be radiologically
and chemieslly characterized.
OFF-SITE PROPERTIES
Ditches : designated for FUSRAP cleanup in 1982. The primary
contamination is Ra-226.R.a-226 is at depth I0S0’ adjacent to western
half of SLAPS between SLAPS boundary and McDonnell Blvd. Rs-266 on
the surface (0-IS em) ranged from 0.1.656 pCi/g adjacent to the western
boundary of SLAPS, extending under McDonnell Blvd.
‘4,
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St. Louis Airport/Hazeiwood/Futura Mining Waste NPL Site Summary Report
Reference 2
Excerpts From Site Plan for St. Louis Airport Site
and Vicinity Properties, St. Louis, Missouri;
Prepared for the U.S. Department of Energy by
Bechtel National, Incorporated; November 1989
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SITE PLAN FOR ST. LOUIS AIRPORT SITE AND VICINI’ry PROPERTIES
ST. LOUIS, MISSOURI
NOVEMBER 1989
Prepared for
UNITED STATES DEPARTIIEPJ’r OF ENERGY
OAK RIDGE OPERATIONS OFFICE
Under Contract No. DE-ACO5—810R20722
By
Bechtel National, Inc.
Oak Ridge, Tennessee
Bechtel Job No. 14501
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FIGURE I-i LOCATION OF SLAPS
(
I
I
.%‘
COLDWATIR CNUK
I%J
I . .-
4
• • INI
0 isi.
—t
I. —
LOUIS
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Site: VP/SLAPS
WBS: 134/153
Date: 10/06/89
II. HISTORY
In 1946, the Manhattan Engineering District (P D). a
predecessor of the Atomic Energy Commission (AEC), and DOE
acquired the 21.7—acre tract now known as SLAPS to store
residues resulting from the processing of uranium ores at a
facility in downtown st. Louis.
The uranium processing (under a D contract) Continued
through 1953; the resulting radioactive residues were stored
at SLAPS. These materials included pitchblende raffinate
residues, radium-bearing residues, barium sulfate cake,
Colorado raffinate residues, and contaminated scrap
(Ref. 1). Most of the residues were stored in bulk on open
ground. Some contaminated materials and scrap ware buried at
the western end and in other parts of the site. To limit
direct radiation exposure to the public, the site was fenced
to prevent casual entry.
In 1966 and 1967, most of the stored residues were sold arid
removed from the site. These residues were transferred to
the the Hazelwood Interim Storage Site (HISS--one of the
Latty Avenue Properties) for storage. On—site structurjs
were razed, buried on the site, and covered with 1 to 3 ft of
clean fill. Although these activities reduced the surface
dose rates to acceptable levels, buried deposits of
uranjum—238, radium—226, and thorjum—230 remained on the site
(Ref. 2).
In 1973, at the request of the city, the tract was
transferred by quitclaim deed from AEC to the City of
St. Louis. The 3.985 Energy and Water Development
Appropriations Act (Public Law 98—360) authorized DOE to
reacquire the property from the city for use as a permanent
disposal site for the waste already on site, contaminated
soil in the ditches surrounding the site, and the waste from
the Latty Avenue Properties, approximately 1 mi to the north
(Ref. 1). Actions to transfer ownership of the SLAPS
property to DOE have been initiated.
From 1976 through 1978, Oak Ridge National Laboratory (ORNL)
conducted a radiological investigation of SLAPS (Ref. 3).
This survey indicated the presenc• of elevated concentrations
of uranium—238 and radium-226 in drainage ditches north and
south of McDonnell Boulevard. In 1983., the drainage ditches
were designated for remedial action under FUSRAP.
0209N 4
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Site: VP/SLAPS
WBS: 134/153
Date: 10/06/89
o Construction of an accese road across the site and
along the west end of the cite
o Excavation of the Slope on the west end of the site
abutting Coidwater Creek
o Construction of a storage pile for the excavated
mate cia I.
o Construction of gabion (i.e. retaining) wall along
Colduater Creek
Prior to the start of the FT 1986 characterization at SLAPS,
BNI prepared a plan to outline the activities necessary to
support the long-term management plan and developed the
engineering packages necessary for the
and geological/hydrological characterization of SLAPS. This
work involved the preparation of detailed cost estimates,
design drawings, technical specifications, schedules, and
requisitions.
In 1985, ORNL performed a radiological survey of the roads
thought to have been used to transport contaminated mat.erial
from the St. Louis sites (Ref. 6). As a result of this
survey, parts of Maze]wood Avenue, Persha] .]. Road, and
McDonnell Boulevard were designated for remedial action in
1986. In 1988 and 1989, BNI performed a radiological
characterization of the roads, as shown in Figure 1-3, and
approximately 70 adjacent vicinity properties. Results from
this characterization effort indicated thorium-230
contamination was present along the rights-of-way of these
roads, extending onto some of the adjacent properties. The
contamination is chal ] .ow (approximately 1 to 2 ft). The
boundaries of contamination for these roads and the vicinity
properties have in general been established.
No formal radiological characterization had been performed on
- the area south of SLAPS until thi r.c.nt (1986-1989)
survsys. This area includes the Norfolk and Western Railroad
prop.rty, which forms the southern boundary of SLAPS. Banshee
Road, and a portion of the St. Louis Airport Authority
property south of Banshee Road. Thorium-230 contamination
was d.t.cted on th. railroad property, at two isolated areas
on Banshee Road, and on portions of the St. Louis Airport
Authority property. The contamination is confined to the top
2 ft of soil.
The •stimated volume of wait. that wt ].1 be collsot.d as a
result of c.m.dial action at the SLAPS vicinity properties is
142.000 yd 3 .
0209N 6
‘4
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• • • • TRANSPORTATION
ROU if S
cAu uI
FIGURE 1-3 LOCATION OF SLAPS AND THE TRANSPORTATION ROUTES
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Site: VP/SLAPS
WBS: 134/153
Date: 10/06/89
IV. RE DIAL ACTION
A. Site Characterization and Scopjng
The following activities were necessary to characterize
the site. These activities were completed in PY 1987.
o Radiological and chemical characterization of the
site.
o Geologic and hydrogeologjc characterization of
the site.
O Radiological characterization of vicinity
properties, including ditches adjacent to the
site, along McDonnell Boulevard, and in and along
Coldwater Creek. NOTE: Additional
characterization is required on Coldwater Creek
to determine the downstream boundaries of
contamination.
Radiological characterization was Completed along t_he
haul routes and vicinity properties in 1989.
In October 1985, BNI initiated engineering activities to
develop the engineering packages necessary for the
radiological/chemical and geological/hydrological
characterizations of SLAPS. These characterization
activities were completed in PY 1987.
Radiological and chemical characterizations were
conducted in accordance with FUSRAP project instructions
and monitoring plans developed for each characterization.
The objective of the characterization was to determine
the vertical and horizontal limits of contamination.
Parameters measured included, but were not limited to,
uranium—238. radium—226, thorium—232, thorium-230, and
soil and water parameters specified in the Resource
Conservation and Recovery Act (RCRA). All composite
samples were subject to multi—element analysis and a
total organic carbon analysis. Results of these analyses
were compared with those made on background soil
samples.
Characterizing the SLAPS ditch., involved analyzing
• archived soil samples from the 1982 EN! survey for
thorium—230. The results of these analyses indicated
that it was necessary to collect additional surface and
subsurfac, soil samples in FY 1987 to adequately
determine the extent of contamination in excess of
0209N Li
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Site: VP/SLAPS
WBS: 134/153
Date: 10/06/89
remedial action guideljne • The DOE guideline for
thorjum—23 0, thorjtjm..232 , and radjum 226 Contamination is
5 pCi/g averaged over the first 15 cm of soil below the
surface and 15 pCi/g when averaged over iS—cm—thick 801].
layer8 more than 15 cm below the surface, averaged over
100 m 2 .
Soil sample analyses indicated elevated levels of
uranium -238 , radium-226, thorium_232, and tborjum...23 0 in
surface and subsurface samples. The radiological
characterization indicated contamination present Ofl SLAPS
to depths as much as 18 ft. Figure IV-1 shows the areas
and depths of radioactive contamination at SLAPS.
Sediment samples were collected from Colduater Creek.
Samples were analyzed for uranjum_238, radium-226,
thorium-232, and thorium-230. Results showed that Spotty
contamination was present from 50 ft Upstream of SLAPS to
the Pershal]. Road intersection Underpass, approximately
1.2 mi north of the site.
Soil samples collected from the Norfolk and Western
Railroad property south of SLAPS, Banshee Road, and the
St. Louis Airport Authority property were analyzed for
uranjum—238. radjum—226, thorjum—232, and tborjum—23 0.
Results showed that contamination was present south of
SLAPS extending to approximately 2 ft in depth in some
areas.
Soil samples were Collected from the rights_of_way of the
haul roads and adjacent vicinity properties. These
samples were analyzed for thorium—230 only because
previous field work had already identified thorjum-23 0 as
the primary contaminant. Results showed that shallow
(approximately 1 to 2 ft) contamination was present.
Results of the metals analyses for SLAPS soil samples
confirmed the presence of some metals (i.e., molybdenum
and cobalt) at concentrations above background.
None of the soil samples analyzed for RCRA
characteristics indicated that the soil is hazardous.
Volatile organic analyses confirm.d the presence of three
compounds in soil including tolu.ne, trichioroethene, and
trans —1.2_dichloro.th.n.. Concentrations of these were,
in general, in the low parts per billion.
Semivolatjle analyses did not identify any Hazardous
Substance List compounds.
0209N 12
‘V
-‘1
-------
NI fR i IRON GROIN) M1ifAC(
FIGURE IV-1 AREAS AND DEPTHS OF RADIOACTIVE CONTAMINATION AT SLAPS
I
-sH. a IlLS ConI hsiIIon
o. . so L I
(A l
US
-------
AREAS ($ KN( WN CONIANINA ION
milloiNc
PROPERlY BOUNDARY
‘ —NO1WOLK
& WESTERN
FIGURE IV-2
AREAS OF CONTAMINATION IN EXCESS OF GUIDELINES AT SLAPS
—ll
0
Q
——
çNCDONNELL
BLVD.
/
BANSIII..E I OAD
I
S S W 5 l ’ 5I
-------
Site: VP/SLAPS
WBS: 134/153
Date: 10/06/89
V. COST AND SCHEDULE
Estj ated costs associated with the portion of work
specifically addressing SLAPS and its vicinity properties
during the time period covered by this plan are listed n
Figures V-i. 2, 3, and 4. The schedule of work for FY 91
through FY 95 as illustrated in Figure V-s and V-6, and the
text of this plan are based upon current progress and
priorities. Therefore, there may be some discrepancies
between cost and schedule.
0209N 22
-------
($000)
ACTiVITY F? 90
FY91 I FY 921
1 ‘
1
BNI
AssEssML’rr
(B&R AH-I0-05-01)
353
1 .552
448
433
F? 94
343
FY95
•
CI . ,L&j.JT .jp
(B&R A11-ZG.05.02)
.
—
-
17.270
—
8.039
14.336
4.895
SUBTOTAl
353
1.552
17,718
—
8.472
—
14.679
ANL
5
25
80
125
100
4.895
HQ
75
115
930
335
470
50
TOTAL
—
433
1,692
—
18.728
—
8.932
15,249
NOlt: Dollars are BA
1Q $ .121O 13
1
FIGURE v-i ST. LOUIS VICINITY PROPERTIES SITE BUDGET
23
-------
( 5000)
ACTiVITY
FY90
FY91
FY92
FY 93
FY94
F? 95
BNI
ASSESSMENT
(B&R AH-l0-05-01)
716
474
1.268
1.659
1.595
.
a.EA.NtJP
(B&R A1 i .10-05-02)
-
670
•
-
4.313
19.784
SUBTOTAL
716
1.144
1.268
1.659
5.908
19.784
ANt
5
50
120
150
150
50
HQ
150
90
70
70
195
sgs
TOTAL
871
1284
1.458
1.879
6.253
20429
NOTE. Dollars are BA
FIGURE V.2 ST. LOUIS AiRPORT SITE BUDGET
24
,O S.l21O 2
4
-------
134 SLAPS VICINITY PROPERtIES
HAUL ROADS CHARACTERIZATION
REPORT DOE REVIEW
PREPARE SCOPING/PLANNING DRAFT
DOCUMENTS ______________________________________________________
PREPARE COMMUNITY
RELATIONS PLAN
REMEDIAL INVESTIGATION
REPORT _____________________________
EE/CA MEMORANDUM FOR
INTERIM REMEDIAL ACTION
ALONG HAUL ROADS _____________________________
DESIGN & PROCURE
SUBCONTRACTS FOR INTERIM
REMEDIAL ACTION ALONG
HAUL ROADS
ENVIRONMENTAL MONITORING
54 34 25 20 25 21 34 28 28 28 28 28
— 1 1 1 1 1
6 6 6 6 6 6 6 6 6 7 7 7
60 40 31 26 31 28 41 35 35 36 35 35
FIVE YEAR PLAN FY90 VS. FY90 BASELINE RECONCtIATION: ThE RVFS PROCESS HAS BEEN ACCELERATED AND STARTED IN FY 89 AND
WtL CONTUIUE IN FY 90. OIIK)INALLY FY 9OPLANNED ACTIVITIES FOR THIS SITE WERE INCLUSIVE TO THE COMPLETK)N OF THE FIELD RI
OF PROPERTIES ALONG THE HAUL ROADS
PROPOSED MILESTONES CONTROLLED BY DOE HO ORO TSD 0 PMC Q ANI
S9ll4l 21
FY90 DETAIL ST. LOUIS AIRPORT SITE VICINITY PROPERTIES, MO
OCTI NOVI DECJ JAN I FEB MAR APR MAY I JUN I JUL lAva ISEP
PUBLISH
F..,
(p
DOE REVIEW DRAFT V
DOE REVIEW DRAFT 7
DOE REVIEW DRAFrç7 FINAL DRAFT V
O
FUSRAP
ANL
HO
TOTAL ($000-BA)
I
FIGURE V-3 FY 90 DETAIL
-------
FY90 DETAIL — ST. LOUIS AIRPORT SITE, MO
____________________ ocTi_NOVI_DECI_JANIFEB MAR_IAPH_IMAYIJUN_Ijui_JAUG_ISEP
189 SLAPS
I M PAFiI- SCOPIMW
PLANNING boi UMENTS DOE REVIEW DRAFT 7
PREPARE COMMUNITY
RELATIONS PLAN DOE REVIEW DRAFT ¶7
REMEDIAL
INVESTIGATION REPORT DOE REVIEW DRAFT ¶7
ENVIRONMENTAL
MONITORING _________________________________________________________
FUSRAP 72 53 69 63 68 48 93 50 51 50 51 48
ANL — — — — — 1 1 1 1 1 — —
HO 12 13 12 13 12 13 12 13 12 13 12 13
TOTAL ($000-BA) 84 66 81 76 80 62 106 64 64 64 63 61
FIVE YEAR PLAN FY90 VS FY90 BASELINE RECONCILIATION THE RI/FS PROCESS HAS BEEN ACCELERATED AND STARTED IN FY80 AND WILL CONTiNUE IN
FY90 ORIGINALLY FY90 PLANNED ACTiVITIES FOR THIS SITE WERE INCLUSIVE TO SURVEILLANCE AND MAINTENANCE ACTIVITIES
PROPOSED MILESTONES CONTROLLED BY DOE HO V 0110 TSD PMC Q ANI
•a ,iiu ie
FIGURE V-4 FY 90 DETAIL
-------
p. .)
.4
6 ’
ST. LOUIS AIRPORT SITE VICINITY PROPERTIES — 5-YEAR PLAN
FY91
FY92
1234
1
234
1
FY93
FY94
FY95
ASSESSMENT
A I/FS - EIS
WORK PLAN
TO PUBUC
1
234
SIGN
ROD
-
1
234
— —
(,
CLEANUP
HAUL ROADS AND VICINITY PROP.
STORAGE OF WASTE AT HISS
—
—
—
—
—
POST-REMEDIAL ACTION REPORT
CERTIFICATION DOCKET
•
— —
113213
9/20/89
FIGURE V-S FY 91 -95 SCHEDULE
-------
‘ASSUMES. FOR THE PURPOSES OF THIS
SCHEDULE. THAT THE SELECTED REMEDIAL
ACTION ALTERNATIVE IS LAND DISPOSAL IN
THE ST LOUIS AREA
Slia I 322I
6
ST. LOUIS AIRPORT SITE 5-YEAR PLAN
1
FY91
FY92
23
41
234
1
234
FY94
FY95
U
RI/FS-EIS
CLEANUP
REMEDIAL ACTION DESIGN
CONSTRUCT DISPOSAL CELL
START CELL OPERATIONS
SIGN
ROD
f )
()
()
—
—
9/20/89
FIGURE V-6 FY 91 -95 SCHEDULE
-------
St. Louis Airport/Hazeiwood/Futura Mining Waste NPL Site Summary Report
Reference 3
Excerpts From Fan ironmental Restoration and Waste Management
Site-Specific Plan for Oak Ridge Operations Office
(Formerly Utilized Sites Remedial Action Program, Missouri);
Prepared for U.S. Department of Ener ; November 1989
‘I.
-------
DOE/ORO/2O7 22 _ 25 g 3
ENVIRONMENTAL RESTORATION AND WASTE MANAGEMENT
SITE-SPECIFIC PLAN FOR
OAK RIDGE OPERATIONS OFFICE
FORMERLY UTILIZED SITES REMEDIAL ACTION PROGRAM
MIS SOUR I
NOVEMBER 1989
Prepared for:
RECEIVED
U.S. DEPARTMENr OF ENERGY
, rnI 1 1 9
OAK RIDGE OPERATIONS orr!CE
p i. SECTION
-------
As of September 1989. 30 sites at which DOE has authority to proceed
have been identified as requiring some form of remedial action, and
one other site has been identified as requiring radiological
surveillance to monitor the effectiveness of past remedial actions
Conducted by DOE’s predecessor agencies. Sites may be added to
FUSRA,P based on (1) the results of ongoing radiological surveys,
health and safety evaluations, and review of authority being
conducted by DOE and (2) legislative actions.
FUSRAP activities have been under way since 1974, with remedial
actions beginning on a limited basis in 1979. Remedial action has
been completed at 10 of the 30 currently authorized sites and has
been initiated at 8 other sites. Preliminary engineering has been
partially completed for 1 of the remaining 12 authorized sites.
The FUSRAP and SFMP site locations are shown in Figure 1.
This Site-Specific Plan (SSP) pertains to the FUSRAP sites in
Missouri, the locations of which are shown in Figure 2. An overview
of these sites is provided in Section 1.2.
1.2 ENVIRONMENTAL RESTORATION AND WASTE MANAGEMENT OVERVIEW
This SSP addresses the assessment and cleanup activities to be
conducted at FUSRAP sites in the State of Missouri. These include:
o St. Louis Downtown Site
o St. Louis Airport Site and Vicinity Properties
o Latty Avenue Properties
None of the sites are owned by DOE, but each site contains
radioactive residues from federal uranium processing activities
during and after World War II. The sites are described in detail in
separate site plans, provided as appendices to this SSP. The site
plans provide specific information regarding sit. locations,
histories, and assessment and cisanup activities performed to date.
0819t 2
-------
2.0 REQUIREMENTS FOR IMPLEMENTATION
DOE has authority under AEA, as amended, to undertake radiological
surveys and other research work, including radiological monitoring,
at sites formerly utilized to support the nuclear activities of
DOE’S predecessor agencies. DOE also has authority under that act
to conduct remedial actions at 25 of the sites identified to date as
requiring some form of remedial action. Public Law 98—50, the
FT 1984 Energy and Water Development Appropriations Act, authorized
DOE to conduct a decontamination research and development project at
four sites: Wayne/Pequanfloc (New Jersey), Maywood (New Jersey).
Co].onie (New York), and Latty Avenue (Missouri) properties.
Public Law 98-360, the FT 1985 Energy and Water Development
Appropriations Act, authorized DOE to acquire title to the St. Lo js
(Missouri) Airport Site and to perform necessary remedial action and
develop the property as a disposal site for the waste already there.
as well as for waste on vicinity properties and the Latty Avenue
properties, consistent with appropriate regulatory requirements and
in a manner satisfactory to the City of St. Louis. Continued
authorization has been provided each year in the passage of the
subsequent Energy and Water Development Appropriations Act.
The St. Louis Airport site, Latty Avenue Properties site, and the
vicinity properties were added to the National Priorities List (NPL)
as one site by the EPA in October 1989. The Wayne/Pequann ock and
Maywood, New Jersey, sites and their vicinity properties were added
to the NPL as two sites by the EPA in December 1982 and September
1983. respecitv.ly.
0819t 6
-------
5.0 ENVIRON NTAL RESTORATION
5.]. TASK DESCRIPTION
The general sequence of events to accomplish environmental
restoration at FUSRAP sites is described in Section 3.2. This
section of this SSP pertains specifically to the Missouri sites and
the actions to be taken there over the next five years.
There are two overall activities to be performed: assessment and
cleanup. Assessment activities are considered to be priority i
because they are ongoing and are designed to reduce health risks
that would be associated with uncontrolled exposure of the general
public to the contamination.
These assessment activities, including a RI/p$-EIS, are the first
steps in the overal l, process of waste cleanup at the sites. Without
completion of these activities, the ROD cannot be reached and
cleanup activities cannot start. Therefore, the driving force
behind this work is the need to initiate the process of
understanding site conditions 80 eventual cleanup can be
undertaken. Discussions with community leaders and officials
regarding the disposition of this waste have been ongoing.
The activities that have been initiated and are needed to complete
the RI/FS—EIS include: field investigations to complete definition
of the nature and extent of the contamination, documentation of the
results of these field investigations, and evaluation of cleanup
alternatives. The assessment activities will culminate in a ROD in
FY 1994 for cleanup of the sites.
Cleanup activities are consid e r.d to be priority i. because they are
follow-up actions to ongoing assessment activities. The cleanup is
necessary to reduce health risks associated with uncontrolled
exposure of the general public and workers to th. contamination.
0819t 17
-------
Remedial actions at the FUSRAP sites in Missouri include all actions
following the signing of the ROD that formally selects the remedial
action alternative to be implemented. The cleanup activities
include design engineering for the waste cleanup and disposal.
preparation and procurement of subcontracts to implement the design
engineering, execution of the cleanup subcontracts, waste
management, verification and certification of the effectiveness of
the cleanup, and surveillance and maintenance of waste disposal
sites. With the completion of a ROD for the sites, cleanup will
proceed.
At present the sites represent a potential health hazard to the
general public. There is no control of off—site contamination to
prevent the further spread of this material. This problem is
magnified by the extensive commercial development in this area.
Because of the potential health risk that the contamination could
pose, the sites were given a priority 1 for cleanup.
Additional information regarding each site is provided in the ‘site
plans provided as appendices. Milestones and schedules are provided
in Section 5.3, and cost is discussed in Section 5.4.
5.2 RESOURCES
Standard industrial equipment and supplies are generally sufficient
for accomplishment of activities at the Missouri sites. Labor
intensive efforts are generally subcontracted to qualified local or
regional contractors. Any need for special equipment or uniquely
trained personnel will be id.ntified as activities progress.
5.3 SCHEDULED MILESTONES
The key milestones for the Missouri sites that fall within the
five-year planning period are listed below. For planning and
budgeting purposes, a disposal site in Missouri is assumed.
08].9t 18
-------
Milestone
Sit. t*ik/Actjvjty Ds!ç j ptjoi. 1 _ L.v.]. Date
All Issue Draft R edia1 Investliation Report 1 08/90
Issue Draft SCQpjfl$/p1* j Documents 2
to EPA
Issue Final Draft Scopin /p1. j Documents 3 09/91
to Public
Issue Record of Decision and Proposed Plan for 3 03/94
Remedial Action
SLAPS Start Construction of Disposal Call 1 06/94
Start Disposal Cell Operations 1 04/95
SLAPS Issu• Final Draft SE/CA for Haul Roads Remedial 2 03/90
Vicinity Action
Proprti.s Publish Certification Dock.t 3 01/95
Latty Avenue Acquire Real Estate Interest in HISS 3 03/9 1
Properties Property
Start Cleanup of Vicinity Properties 1 10194
St. Louis Publish Characterization Report, Phase 1 & 2 2 03/90
Downtown Site
Milestones: 1—Site; 2—ORO; 3—HQ
The detailed schedules for each Missouri site are provided in the
appropriate appendices.
5.4 COST
Figure 5 is provided to show the overall costs for FUSRAP sites,
including costs for DOE Headquarters and ANL activities-_which
pertain to all four sit, groups. The overall cost for the Missouri
sites, excluding Hsadquart.rs and ANL costs, is illustrated in this
figure. Spscific dollar amounts by activity and year are provided
in Table 1.
0819t 19
U
-------
St. Louis Airport/HazelwoodfFutura Mining Waste NPL Site Summary Report
Reference 4
Telephone Communication Concerning the Current Status
of the St. Louis Airport Situ; From Sue MeCarter, SAIC,
to Gene Gunn, EPA Region VU; D ember 18, 1990
-------
TELECOMMUNICATIONS
SUMMARY REPORT
SAIC Contact: Sue McCarter Date: 12/18/90 Time: 930 a.m.
Made Call X Received Call —
Person(s) Contacted (Organization): Gene Gunn, Region V I I Remedial Project Manager
(913) 551-7776 [ Gene is no longer Remedial Project Mankger - contact Greg McCabe at
(913) 551-7709]
Subject: Current Status - St. Louis Airport
Summary: (The majority of Federal sites have been lumped into one unit.) Current Status: Federal
Facilities Agreement (IZO LAG CERCLA) was signed and made final in late June. It became
effective on August 17, after a public comment period, etc.
This Federal Facilities Agreement establishes DOE as the lead agency. It ‘ ill be doing all the work,
removal actions, etc. (“what they do, they earn.”) EPA has oversight authority and has final say
over final remedy selection. The agreement is basically a procedural one that sets out requests and
schedules for primary documents, which include Remedial InvestigationlFeasibility Study, ROD,
proposed plan, and remedial action. DOE has submitted a schedule - EPA has approved it. The
ROD is scheduled to be completed in 1994.
-------
St. Louis Airport/Hazeiwood/Futura Mining Waste NPL Site Summary Report
Reference 5
Excerpts From St. Louis Airport Site Annual Site Environmental Report,
St. Louis, Missouri, Calendar Year 1988; Prepared for the U.S. Department of Energy
by Bechtel National, Incorporated; April 1989
-------
DOE/0RJ20722-220
Formerly Utilized Sites Remedial Action Program (FUSRAP)
Contract No. DE-ACO5-81 0R20722
ST. LOUIS AIRPORT SITE
ANNUAL SITE ENVIRONMENTAL REPORT
St. Louis, Missouri
Calendar Year 1988
O1$ .O2 O a
k
Bechtel Nationai, Inc.
-------
SLAPS is located in the upper half of the Coidwater Creek
watershed. Coidwater Creek originates about 5.8 km (3.6 ml) south
of SLAPS at a small, spring-fed lake in Overland, Missouri; flows
along the western end of the site; and discharges to the MiSSOUrI
River approximately 6.4 km (4 ml) upstream of its confluence with
the Mississippi River. Passing through culverts under the
Lambert-St. Louis International Airport, flow in Colduater Creek is
influenced by stormuater runoff from the upstream areas of
residential, commercial, industrial, and airport land (Ref. 1) (see
Figure 3-1).
Rainwater runoff from SLAPS leaves the site by evaporation, seepage
into groundwater, or surface drainage to Coidwater Creek. Surface
drainage from the site is intercepted by drainage channels along crie
northern and southern boundaries of the site that direct flow into
Coidwater Creek. To halt erosion of the western end of SLAPS, a
gabion wall consisting of rock-filled wire baskets was constructed
in 1985 along the section of Coldwater Creek bordering the site.
There are no facilities on Colduater Creek that withdraw water for
human consumption. Coldwater creek empties into the Missouri RIver,
which in turn empties into the Mississippi River. The closest water
treatment facility is on the Mississippi River, approximately 12.8
km (8 mi) downstream of the confluence of the Mississippi and the
Missouri (Ref. 2).
Groundwater at SLAPS occurs in two basic systems. The first is t e
groundwater being monitored at the site as the “upper” and “lower”
groundwater systems that occur in unconsolidated glacial sediments
and are thought to be hydraulically connected. These groundwater
systems yield insufficient quantities f water to wells installed at
the site to be considered aquifers. The second basic system is the
bedrock aquifer located in Paleozoic limestones several hundred feet
beneath the site. The groundwater in the bedrock aquifer is
typically of poor quality (Ref. 2), containing more than 1,000 ppr
of dissolved solids, and is classified as saline (Ref. 3). In
addition, yields from wells in this aquifer are very low, with
4
‘1
-------
reported specific yields of less than 7.6 1/minIm (2 gal/rninlft) of
drawdown. There are no plans at present to install monitoring wells
in the bedrock aquifer at the iite. Groundwater is not generally
used for any purpose in the SLAPS area, and the nearest well is
about 2.4 km (1.5 m l) north of the site. The water needs for the
area are met with treated Mississippi River water.
The climate at SLAPS is classified as modified continental. The
average annual daily temperature ranges from 7.4 to 18.6°c (45.4 t
65.5°F). The highest average monthly temperature is 31.6°C (89°F)
(July) and the lowest is -6.7°C (19.9°F) (January). Normal annual
precipitation is slightly over 87.5 cm (35 in.). The average annual
snowfall is 65.8 cm (26.3 in.). Prevailing winds tend to be frotr
the south, the northwest, and west-northwest. Average wind speeds
range from 12.2 to 18.9 km/h (7.6 to 11.8 mph). Figure 1-3 shows
the distribution of wind direction and speed for the SLAPS vicinity
(Ref. 4).
There are no sizeable residential population centers within 1.6 k-
(1 m l .) of the site. The nearest population center comprises 75 tc
100 people residing about 0.8 km (0.5 mi) west of the site in an
industrially zoned area of Hazelwood. The next nearest (about 1.533
people) is about 1.6 km (1 mi) northwest of the site along Chapel
Ridge rive. Most of Hazelwood’s population is north of Interstate
270, more than 2.4 km (1.5 mi) north of the site (Ref. 2). Land use
immediately adjacent to the site is varied (Figure 1-4. Ref. 2).
More than two-thirds of the land within 0.8 km (0.5 mi) of the site
is used for transportation-related purposes, primarily Lambert-St.
Louis International Airport. Land immediately adjacent to the site
is also used for commercial and recreational purposes.
1.2 SITE HISTORY
In 1946, the Manhattan Engineer District (MED). a predecessor of the
Atomic Energy Commission (AEC) and DOE, acquired the 8.8-ha
(21.7-acre) tract now known as SLAPS to stor. r.siduss r• u1ting
fzo th proc.i.in of. uzantu ores at a tactl..ity ifl St. Louis.
5
‘3
-------
Uranium processing at this facility was conducted under a contract
with MED/AEC until 1957. Processing residues sent to the tract now
known as SL.APS included pitchblende raffinate residues.
radium. bearing residues, barium sulfate cake. Colorado raftinate
residues, and contar inated scrap. Most of the residues were Stored
in bulk on open ground. Some Contaminated materials and scrap were
buried at the western end and in other parts of the site. To lin it
direct radiation exposure to the public, the site was fenced to
prevent casual entry.
in 1966 and 1967. most of the stored residues were,,% ’ ’ and moved
approximately 0.8 km (0.5 mi) north toa sit on Latty Avenue .
On-site structures were razed, buried on the site, and covered with
0.3 to 1 m (1 to 3 ft) of clean fill. Although these activities
reduced the surface dose rates to acceptable levels, buried depcs: s
of residue containing uraniun-238, radium-226, and thorjutT . 230
remained on the site (Ref. B).
in 1973, the tract was transferred by qui.tclairn deed fror AEC tc t ie
City of St. Louis, at the City’s request. The 1985 Energy and Waer
Appropriations Act (Public Law 98-360) authorized DOE to take the
necessary steps to consolidate and dispose of waste materials fro—
the Latty Avenue site and the nearby St. Louis Airport vicinity
properties locally by reacquiring, stabilizing, and using the old
8.8-ha (21.7-acre) AEC airport site in a manner acceptable to the
City of St. Louis.
From 1976 through 1978, ORNL conducted a radiological 1nvestigaticr
of SLAPS (Ref. 6). This survey indicated the presence of elevated
concentrations of uranium-238 and radium-226 in drainage ditches
north and south of McDonnell Boulevard. in 1981. the drainage
ditches were designated for remedial action under FUSRAP.
In 1982. ENI performed radiological characterizations of the ditches
on either side of McDonnell Boulevard and portions of Coldwater
Creek (Ref. 7). Neither of these surveys included measuring
thorlum -230 in soil. During’l986, however, archived soil samples
8
-------
from the ditches were reanalyzed to determine thorium-230 content,
and new samples from the ditches and Coidwater Creek were
radiologically and chemically analyzed. -
Additional radiological characterization and limited geological and
chemical characterization of SLAPS were undertaken during 19Sf arid
included installation of 10 groundwater monitoring wells at the
site. Radiological characterization was also performed on three
properties immediately adjacent to SLAPS: the ball field property
north of the site, the railroad bordering the site on the south, and
a triangular-shaped area between the SLAPS fence line and McDonnell
Boulevard at the eastern end of the site.
There are no continuing commercial or industrial activities at
SLAPS: therefore, no radioactive effluents exist at the site...
1.3 HYDROGEOLOCICAL CHARACTERISTICS OF THE SITE
This section presents data on the hydrogeoloqypat SLAPS. The
interpretations are ba..d on groundwater levels m.asvr.d in calendar
year 198w An early set of monitoring wells at the site was
installed by Roy F. Weston, Inc., in 1981 (Ref. 8). These wells are
not used for groundwater level measurements but are used to obtain
samples for environmental monitoring. The groundwater monitoring
wells where wat.x- lev. s were measured to collect data for this
report i(Figure 1-5)’ ataUe4 at SLAPS by BN1 in mi.d-l986
(Ref. 9). Twenty-seven additional wells were installed by 3N1 in
1968 at the adjacent ball field. The ball field wells nearest to
SLAPS supplement the groundwater level monitoring presented in this
report and are also shown in Figure 1-5. A summary of well
construction information is given in Table 1-1. An example of well
construction details is included as Appendix E.
In previous reports the two groundwater systems at SLAPS have been
referred to as “shallow” and “deep” (Refs. S and 9). In this report
the two groundwater systems monitored are designated “upper” and
“lower” to be consistent with data being reported for the ball field
9
-------
area (Ref. 10). Background information on site geology.
hydrogeology. and well installation methods can be found in
Refs. 8-10.
Groundwater levels at SLAPS were measured weekly with an electric
downhole probe water level indicator.
1.3.1 Upper Groundwater System
The unconfined upper groundwater system occurs in a zone
approximately 3.4 to 10.7 in (11 to 35 ft) below the ground surface
(Ref. 8). Wells in this zone are screened in unconsolidated glacial
materials at depths from 3.4 to 10.1 in (1]. to 33 ft) above a clayey
aquitard (Ref. 9). Groundwater surface elevations measured in 1968
for each well are shown as hydrographs (Figures 1-6 and 1-7).
Precipitation records for the St. Louis area are presented with the
hydrographs in Figures 1-6 and 1-7.
The hydrographs for the upper groundwater system show apparent
seasonal fluctuations in groundwater levels. The water levels are
highest during late winter-early spring, then slowly fall 0.6 to
2.4 n (2 to 8 ft) until the lowest water levels are reached in the
fall. Except during December, the changes in water levels correlate
froim well to well. In December the water levels for wells M10-8$,
M13.S-8.5s, and M11-9 dropped. while the rest of the water levels
were relatively steady. This behavior may be associated with
discharge of shallow groundwater into the Colduater Creek channel.
Correlation between precipitation and water levels is not
consistent. Apparently, minimal recharge occurs at the site.
The slope and flow direction of the upper groundwater system were
determined from potentiometric surface maps. (Potentiometric
surface is defined as the level to which water will rise in tightly
cased wells. Delineation of the potentiometrjc surface of an
aquifer indicates groundwater slope and flow direction.) The dates
for the information shown on these two maps (Figures 1-8 and 1-9)
13
‘I
-------
FIGURE 1-8 SlAPS UPPER GROUNDWATER SYSTEM
POTENTIOMETIIIC SURFACE (3/18/88)
0 500
‘,(.AIt IPIII I I
A I AI’I’lk )%IMA II
(
FIELDS
D53W 10S
053W14S
0
( ‘ v i ’ ,
520.80
SN I*H
MONITOR WELL INSTALLED’ I I8
MONITOR WElt I 1STALLEP %98G
DIRECTION UI (;fl)IJP4UwAJ [ fl FLOW
S FT CON IOURS IN 11 1.1 A&)V( MEAN SEA LEVI
ELI VA lION ( POIINIIOMF TRIG SURFACE IN FEE
Allovi MI AN t A I I VI
-------
UFAN SEA LFVEL
SURFACE IN FEE I
FIGURE 1-9 SLAPS UPPER GROUNDWATER SYSTEM
POTENTIOMETRIC SURFACE (11/11/88)
0 500
i;ait wii iii
SCAt I APt’ItOMIMAH
is
‘4
RAIL FIELDS
i5
o BS3WIOS
5 16.6
520
525.4
ss s IWb
MONITOR WELL INSTALLED 1988
MONITOR WElL INSTALLED 1986
DIRECTION OF GROUNDWAIER Ft OW
SIT CONTOURS IN 1(11 AROVE
ELEVATION OF POTENTIOMETIIIC
AIIOVE M i AN I A II VI t
-------
were chosen because they represent seasonal high and low water level
periods and are the same dates used to ;repare potent iometric
surface contour maps for the adjacent ball field area
characterization report (Ref. 10). The groundwater flow direction
is generally east to west. The contours suggest a flow direction
approximately parallel to the site topography (Ref. 8. P. 4-3) with
discharge into Coidwater Creek. The hydraulic gradient for both
dates is on the order of 0.009.
1.3.2 Lower Groundwater System
The lower groundwater system is located in the glacial sediments
below the clayey aquitard and above bedrock (Ref. 9). approximately
10.7 to 26.5 nt (35 to 87 ft) below the ground surface. The lower
system wells are screened at depths ran ing from 11 to 26.5 m (36 to
87 ft). Hydrographs of wells monitoring the lowe groundwater
system are shown in Figure 1-10. Precipitation records for the St.
Louis area collected at the St. Louis Airport are also shown on the
hydrographs.
The hydrographs for the lower system (Figure 1-10) show little
seasonal variation of water levels. Water levels in wells M10-1SD
and M10-25D show a slow but steady drop amounting to almost 0.9
(3 ft) over the course of the year. Well M13.5-8.SD water levels
fluctuated 2.4 in (8 ft) during September-October and the year-end
level declined 5 ft in 1988, as did those of MlO.1SD arid M10-25D
Water levels in M10-8D rose during 1988, except for the last
measurement. The reason for the inconsistent behavior of the lowe:
system wells is not known, but the overall effect of this behavior
on hydraulic gradient and flow direction is minimal. Correlation :f
the water levels with the precipitation record is inconsistent.
Hydraulic gradient and flow direction for the lower groundwater
system were determined using two potentiometric surface contour maps
(Figures 1-11 and 1-12) from the water level measurements for the
same dates as those for Figures 1-8 and 1-9. The potentiometric
surface maps show a consistent flow direction from east to west.
18
‘3
-------
t
DJI
*— *_*--* )I(-*--*-*-
IHII—*--*- *-*-*.*
0—n oc
ea—Ge
30(1(11
.r
‘fl -fl Elf) I.}F) (it3
G- -4-E s—-- - ) 0 e O- 4— -.
2
I
MI SOURI SITES PRECIPUATK N (INCIWS)
L_ .I..L I ..
JAN FEB MAR
LEGEND: 0 MIOtSO
* MIO.250
o uioeo
x M13515D
AI’fl
MAY
JUN JUl
TIME, month.
YEAR 1980
SEP OCT
NOV DEC
FIGURE 1-10 HYDROGRAPHS OF LOWER GROUNDWATER SYSTEM
WELLS M10-15D, M1O-25D, M1O-8D, AND M13.5-O.5D
‘I
ti
I
A
U
p
I
0-
0
0
I)1t
-)( ,(
NOIE: MONIIItY AVG. FOIl
NO DATA FOR JULY.
I
J
.1111
-------
• MONITOR WELL INSTALLED 1906
DIRECTION OF GROUNDWATER FLOW
2 FT CONJOURS IN FEEl AAOVE MEAN SEA LEVEL
ELEVATION OF POTENTIOMETRIC SURFACE IN FEET
ABOVE MEAN SEA ( (V II
FIGURE 1-11 SLAPS LOWER GROUNDWATER SYSTEM
POTENTIOMETRIC SURFACE (3/18/88)
o 500
S(.AII *1111 I
SCAII APPIK*W1A1l
0
-------
3.1 RADON SAMPLING
Nine radon detectors are maintained along the site boundary. spaced
so as to ensure adequate detection capability under most atmospheric
Conditions. The locations of the radon monitors are shown in
Figure 3-1. Three background detectors are maintained off-site.
Radon concentrations are determined using monitors purchased fror
the Terradex CorporatiorL. These devices (Terradex Type F
Track-Etch) consist of an alpha-sensitive film contained in a small
plastic cup covered by a membrane through which radon can diffuse.
Radon will diffuse through the membrane (in or out of the cup) when
a concentration gradient exists; therefore, it will equilibrate With
radon in the outside air. Alpha particles from the radioactive
decay of radon and its daughters in the cup create tiny tracks when
they collide with the film. When returned to Terradex for
processing. the films are placed in a caustic etching so lutiofl to
enlarge the tracks. Under strong magnification, the tracks can be
counted. The number of tracks per unit area (i.e., tracks/tr . 2 ) is
related through calibration to the concentration of radon in air.
Fresh Track-Etch monitors are obtained from Terradex each quarter.
Site personnel place these units in each sampling location and
return the exposed monitors to Terradex for analysis.
Table 3-1 reports the radon concentrations measured at the nine
monitoring locations. The annual average concentrations ranged fro—
7 x 10 to 2.1 X 1O aCi/ml (0.7 to 2.1 pCi/l). Background
concentrations ranged from 4 x to s x io biCi/mi
(0.4 to 0.5 pCi/i) and have not been subtracted. Based on measured
radon concentrations at SLAPS, the on-site radon source has a
minimal effect on radon concentrations in the area.
For comparisons of radon concentrations measured from 1984 through
1988, see Subsection 3.6.1.
27
-------
£ SURFACE WAFE N *NO$tl Iw( SAMP( INU I OCAIION
• GROUNDWAV(R UUNI!ORING WELL
• NAII pN ANt) I II I RNAI OANA RAUIAINJN MONI1ORINU IOCAI•ON
i
• NIl 21
I :
p . .,
(a)
• PAlO IS SlOA
MIO7SSID
“I®
:-—-r--—---—
RAW WATER FROM MISSISSIPPI
CHAIN OF ROCKS WATER
TREATED WATER
NOT TO SCALE
FIGURE 31 SLAPS ENVIRONMENTAL MONITORING LOCATIONS
-------
TABLE 3-1
CONCENTRATIONS OF RADOW-222 AT SLAPS. 1988
Sampling
Locationa
Number of
Samples
Minimum
(10-9
Maximum
ci/m1)b.c
Average
1
4
0.3
2.9
1.].
2
4
0.5
1.7
1.2
3
4
0.7
1.5
1.0
4
4
0.6
1.2
1.0
5
4
0.7
4.6
2.1
6
7 d
4
4
0.5
0.4
1.0
1.1
0.8
0.7
8
4
0.5
2.9
1.8
9
4
0.4
2.0
1.0
Background
4
2
0.3
0.4
0.6
0.4
0.4
16 e
17 f
18 g
0.4
asampling locations are shown in Figure 3-1.
bBackground has not been subtracted. Note that some
locations have radon concentrations below background.
C 1 x 10 Ci/m1 is equivalent to 1 pCi/i.
dLocat ion 7 is a quality control for Location 3.
eLocated in Plorissant, MO. 26 km (16 mi) northeast of SLAPS.
Located at McDonnell Blvd., 0.8 km (0.5 mi) east of SLAPS.
Established in April 1988.
L.ocated in St. Charles County. MO. approximately 32 km
(20 mi) southwest of SLAPS. Established in April 1988.
29
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3.2 EXTERNAL GAMMA RADIATION LEVELS
External gamma radiation levels were measured at the nine monitoring
locations that correspond to the radon (Terradex) detector locat ons
shown in Figure 3-1.
External gamma radiation levels are measured using lithium fluoride
(LiF) thermoluminescent dosimeters (TLDs). Beginning in 1988, the
system of measurement utilizes tissue-equivalent dosimeters to
provide values that are more realistic in terms of radiation dose to
the tissues of the body at a depth of 1 cm. This dosimetry syste—
offers advantages in accuracy and sensitivity that were not
available with the system used previously.
Each dosimetry station contains a irinimum of four dosimeters, which
are exchanged after one year of accumulated exposure. For example.
a dosimeter placed in the station in October 1987 would be ret oved
in October 1988. Each dosimeter contains five individual LiF chips
(each group of which was preselected on the basis of having a
reproducibility of ± percent across a series of laboratory
exposures). the responses of which are averaged. Analysis is
performed by Thermo Analytical/Eberline (TMA/E). The average value
is then corrected for the shielding effect of the shelter housing
(approximately 8 percent) and for the effect of fade.
Fade is the loss of dose information brought about by environenza .
effects, primarily high summer temperatures. Fade is determined by
collocating dosimeters that have bean exposed to a known level of
radiation (called a spike) before they are placed at a minimum of
two stations, generally on the eastern and western boundaries of a
site. The fade factor can be determined by subtracting the station
radiation value from the fade control dosimeter radiation value
followed by dividing by the known spike level. The corrected value
is then converted to milliroentgens per year by dividing by the
number of days of exposure and subsequently multiplying by 36S days.
30
‘3.
-------
Some differences in external gamma radiation values may be noted in
the 1988 data in comparison With the 1987 values. The current
measurement system is more Sensitive to low radiation levels and
more accurate in its resolution than the system used previously.
Therefore, some stations that previously demonstrated no measurable
external gamma radiation value in excess of background now exhibit a
small measurable value. Similarly, at some other stations values
are higher or lower because of the improved method of measurement,
not because of deterioration of site conditions or remedial action.
The results of the measurements for external gamma radiation are
presented in Table 3-2. Annual radiation levels ranged from 38 to
2128 mR/yr above background at the monitoring locations. The
highest radiation level occurred at Location 2, which is in an area
known to be contaminated. The elevated level is due to this
station’s proximity to a ditch that is located between the site
fence and McDonnell Boulevard (Ref. 7). The radioactive
contamination in the ditches will be cleaned up as part of the,
remedial action to be conducted at the site, and these areas will be
monitored along with the site itself until remedial action is
complete.
The next highest annual average gamma radiation level measured at
the SLAPS in 1988 was 129 mR/yr above background. The annual
average background radiation level was 73 mR/yr. For comparisons of
external radiation levels measured from 1984 through 1988. see
Subsection 3.6.2.
The background external gamma radiation value for a given location
is not a static constant. Because the background radiation value ‘ s
a combination of both natural terrestrial sources and cosmic
radiation sources, factors such as the location of the detector in
relation to surface rock outcrops, stone or concrete structures, or
highly mineralized soil can affect the value measured. Independent
of the placement of the detector at the Earth’s surface are the
factors of site altitude, annual barometric pressure cycles, and the
occurrence and frequency of solar flare activity (Ref. 17).
31
-------
TABLE 3-2
EXTERNAL GAMMA RADIATION LEVELS AT SLAPS. 1988
Sampling
Locationa
Number
Measureme
of
nts
Radiation
Level
(mR/yr)b
Minimum
Maximum
Average
1 4 30 56 47
2 4 1898 2229 2128
3 C 4 81 122 10].
4 4 16 48 38
5 4 17 70 45
6 4 24 53 43
4 77 167 129
8 d 4 21 49 38
9 4 88 183 129
16 4 63 86 73
asampling locations are shown in Figure 3-1.
bMeasured background has been subtracted from the readings
taken at the nine sampling locations shown in Figure 3-1.
CLocatjons 3 and 7 are quality control locations.
dLocation 8 was moved in April 1987.
ej April 1988. background detectors were installed at
McDonnell Blvd., 0.8 km (0.5 mi) east of SLAPS, and in St.
Charles County. approximately 32 km (20 mi) southwest of
SLAPS. Because the instruments have been in place for less
than 1 year. data will not be reported until 1989.
t Located in Florissant. MO. 26 km (16 mi) northeast of SLAPS.
32
-w
-------
Because of these factors, the background radiation leve ] , is not
constant from one lo:ation to another even over a short time. Thus
it is not abnormal for some Stations at the boundary of a site to
have an external gamma radiation value less than the background
level measured some distance from the site.
In April 1988, additional background monitoring locations were
established at the Federal Aviation Administration Building, located
0.5 !fli east of SLAPS at McDonnell Blvd.. and at St. Charles County
Airport. located approximately 32 km (20 mi) southwest of SLAPS Lfl
St. Charles County. Because the 6 months of exposure time is not
representative of the yearly fluctuations in background that occur
because of seasonal weather variations, data from these locations
will not be reported until 1989.
3.3 WATER SAMPLING
During 1988, sanpling was performed to determine the concentrations
of uranium, radium, and thorium in surface water and groundwater at
both off-site and on-site locations (Figure 3-1).
3.3.1 jface Water
Surface water samples were collected quarterly from four off-site
locations. Water samples were taken from Colduater Creek
approximately 15 m (50 ft) downstream of the ditch that runs along
McDonnell Boulevard (Location 1) and at the intersection of the
creek and Interstate 70 (Location 2). Location 2 is upstream of
SLAPS and provides an Indication of background concentrations.
Locations 3 and 4 are at the Chain of Rocks Water Treatment Plant
downstream of the point at which Coidwater Creek discharges into the
Missouri River. which then discharges into the Mississippi River.
Samples were collected using nominal 1-liter (0.26-gal) grab samples
to fill a 4-liter (1-gal) container and were analyzed by TMA/E.
Total uranium was determined by a fluormetric method. Radiuin-226
concentrations in water were determined by radon emanation. (This
33
-------
method consists of precipitating radium as Sulfate and transferring
the treated sulfate to a radon bubbler, where radon-222 is allowed
to come to equilibrium jth jt radium- 226 parent. The radon-222 is
then withdrawn into a scintillation cell and counted by the gross
alpha technique. The quantity of radon-222 detected in this manner
is directly proportional to the quantity of radium-226 originally
present in the sample.) Thorium-230 was eluted in solution,
electrodeposited on stainless steel discs, and counted by alpha
spectrometry.
The results of analyses for uranium, radium-226, and thorjurn-230 at
all sampling locations are presented in Table 3-3. The average
concentrations of each of these radionuclides at the three sampling
locations downstream of SLAPS were nearly equal to the background
concentrations measured upstream of the site. These values may be
compared with the levels of radioactivity in the commonly consu’red
liquids listed in Appendix D of this report.
For comparisons of radionuclide concentrations measured in surface
water from 1984 through 1988, see Subsection 3.6.3.
3.3.2 Groundwater
During 1988, groundwater samples were collected quarterly from 16
on-site wells., Samples were collected by a hand bailer after the
wells had been pumped dry or three well casing volumes had been
removed and ample time had been allowed for well recharge. Norr na
1-liter (0.26-gal) grab samples were collected to fill a 4—liter
(1-gal) “container. Samples were analyzed by ThA/E for total
uranium, dissolved radjum-226. and thorjum-230 using the methods
applied to surface water analyses (see Subsection 3.3.1).
Results of analyses for concentrations of total uranium, radium, arid
thorium in groundwater are presented in Table 3-4. Averages for
radium-226 ranged from 3 x 1O to 9 x 1O Cj/Thl
(0.3 to 0.9 pCi/i). For thorium-230, averages ranged from
34
0
-------
TABLE 3-3
CONCENTRATIONS OF TOTAL URANIUM, RADIUM-226. AND THORIUM- 230
IN SURFACE WATER IN THE VICINiTY OF SLAPS. 1988
Sampling
Locationa
Number of
Samples
Concentration
cio-
Minimum
Maximum
i Ci/tnl)b.c
Average
Total Uranium
4
4
3 e
3 e
<3
<3
3
3
5
5
3
4
4
4
3
1
2 d
3
4
Radium- 226
1
2 d
3
4
4
4
3e
3 e
0.2
0.2
0.].
0.1
0.4
1.3
0.4
0.3
0.3
U.s
0.3
0.2
Thor iut - 230
4
4
3 e
3 e
0.1
<0.1
0.3
0.5
0.2
0.4
0.3
0.1
0.3
1
2 d
3
4
asampling locations are shown in Figure 3-1.
b 1 x i - i Ci/ml is equivalent to 1 pCi/i.
CWhere no more than one value is less than the limit of
sensitivity of the analytical method, values are considered
equal to the limit of sensitivity, and the average value
is reported without the notation “less than.”
dLocatlon is upstream of the site and acts as background.
Background values have not been subtracted.
esamp]es lost in transit to the laboratory in the fourth
quarter.
35
-------
TABLE 3-4
(coat inued)
qe 2 of 2
Sampling Number of
Locatjoria Samples
Concentration (l0-
UC1/fl%l)b.C
Minimum
Maximum
Average
Radium-226 (continued)
Background
Well BS3WO1S 2 d
Well BS3WO1D 2 d
0.3
1.0
0.8
1.1
0.6
1.1
Thor ium-230
Well A 4
1.].
4.9
2.8
Well B 4
1.3
3.2
2.0
Well C 4
<0.1
0.4
0.3
Well D 4
0.4
1.3
0.9
Well E 4
0.2
14.0
4.8
Well F 4
1.1
3.0
2.0
Well M10-25S 4
0.2
0.6
0.4
Well Ml0-25D 4
0.2
0.9
0.5
Well M11-21 4
8.0
130.0
S2.0
Well M10-1SS 4
1.3
17.0
5.3
Well M10- .1SD 4
0.1
4.5
1.3
Well Ml0.-8S 4
0.2
1.].
0.5
Well Ml0-8D 4
0.1
0.6
0.3
Well M1] .-9 4
0.3
2.6
1.0
Well M13.5-8.SS 4
0.2
1.1
0.7
Well M13.5-8.5D 4
0.2
0.9
0.7
Background
Well BS3WO1S 2 d
0.1
0.2
0.2
Well BS3WO1D 2 d
0.2
0.2
0.2
asa 1ing locations are shown in Figure 3-1. Background
locations are shown in Figure 1-5 as WO1D and W0].S.
b 1 x Ci/ml is equivalent to 1 pCi/i.
Cwhere no more than one value is less than the limit of
sensitivity of the analytical method, values are considered
equal to the limit of sensitivity, and the average value
is reported without the notation “less than.”
dNew wells; first sampled in duly 1988. Located at
Byassee Drive, approximately 0.8 km (0.5 mi) northwest of
SLAPS.
37
-w
-------
3 x l0 to 5.2 x Ci/ml (0.3 to 52 pCi/i). Averages for
total uranium in groundwater ranged from <3.0 x 10 to
s.s x Ci/ml (<3 to 5,590 pCi/i).
Concentrations of total uranium in several of the shallow wells at
SLAPS are high because the wells are located in areas of known
subsurface contamination. However, because SLAPS s fenced, the
public does not have access to these wells; furthermore, there is no
known consumption of groundwater in the vicinity of the site.
Groundwater that might discharge to Coidwater Creek is monitored as
part of the surface water monitoring program. Current indications
are that this potential transport pathway has not resulted in
degradation of surface water quality. As a result, there is no
evidence that anyone is being exposed to levels of radiation that
approach the DOE radiation protection standard of 100 mrem/yr.
For a discussion of the comparisons of radionuclide concentratiofls
in groundwater measured from 1984 through 1988, see Subsection 3.6.4.
3.4 SEDIMENT SA 4PLING
During 1988. samples consisting of approximately 500 g of sedinent
(1.1 ib) were collected oft-site at surface water sampling
Locations 1 and 2 (Figure 3-1). THAI! analyzed the samples for
total uranium, radium-226. and tPioriuin-230. Total uranium
concentrations were obtained by summing the results from isotopic
uranium analyses. Isotopic uranium and thorium-230 were deterr ’ir ed
by alpha spectrometry, wherein the uranium and thorium-230 are
leached, extracted, and electroplated on metal substrates.
Radium- 226 concentrations were determined by radon emanation.
Analytical results for uranium. radium-226. and thorium-230 (based
on dry weight) are presented in Table 3-5. The annual average
concentration of total uranium. radium-226. and thorium-230 at the
downstream sampling location was 2.6, 1.0, and 5.4 pciig.
respectively. These concentrations of radium-226 are lower than
background concentrations measured at upstream Location 2. Total
38
-------
TABLE 3-S
CONCENTRATIONS OF TOTAL URANIUM, RADIUM-226, AND THORItJM-230
IN SWIMENT IN THE VICINITY OF SLAPS, 1988
Sampling
Locationa
Number of
Samples
Concentration [ Cifg
(dry)1
Minimum Maximum
Average
Radium-226
4
4
0.9
1.0
1.1
1.9
1.0
1.5
1
2
Thor iuin-230
4
4
2.7
0.4
8.0
3.3
5.4
1.3
1
2
Uraniur - 234
4
4
1.1
0.8
1.3
1.0
1.2
0.9
1
2
Uraniurn-235
1
2
4
4
<0.1
<0.1
0.1
<0.1
<0.].
<0.1
Uranium- 238
4
4
1.2
0.6
1.3
0.8
1.3
0.7
1
2
Total Uraniumb
4
4
2.4
1.5
2.7
1.9
2.6
1.7
1
2
asampling locations are shown in Figure 3-1. Location 1 is
downstream and Location 2 is upstream of the site.
bTotal uranium concentration for each location is determined
by summing the measured concentrations of each isotope for
the respective location.
39
-------
Subsection 3.5.1. Measured radon Concentrations are discussed fully
in Subsection 3.1.
3.5.1 Dose to the Maximally Exposed Individual
To identify the individual in the Vicinity of SLAPS who would
receive the highest dose from on-site radioactive materials, the
dose from exposure to external gamma radiation was calculated at
various monitoring locations that could be accessible to the
public. From these calculations, it was determined that the highest
overall dose would be received by an individual who walked daily
along the northern site boundary. Because the area adjacent to
SLAPS is normally unoccupied, exposure was calculated assunt]ng that
the maximally exposed individual walked along the fence line twice a
day, 5 days per week. It was also assumed that the individual
walked at a rate of 4.8 km/h (3 mph) along the 0.8 .km (0.5-mi)
northern site boundary and during this period was exposed to an
average of the annual exposure rates observed at Locations 1. 2.
and 3.
The external exposure to this individual would be 7.5 mR/yr above
background. Because 1 mR 5 approximately equivalent to 1 mrerr,
this exposure is approximately equivalent to 7.5 percent of the DOE
radiation protection standard of 100 mrem/yr and is approximately
equal to the exposure a person would receive during two round-trip
flights from Los Angeles to New York as a result of the greater
amounts of cosmic radiation at higher altitudes (see Appendix D).
This scenario is highly conservative in that it is unlikely that any
individual would spend so much time at this location. A more
realistic assessment of the use of the site would demonstrate that
the incremental dose is less than 1. mrem/yr.
3.5.2 Dose to the Population in the Vicinity of SLAPS
The dose to the population represents the conceptual cumulative
radiation dose to all residents within an 80-km (50-mi) radius of a
given site. This calculated dose includes contributions from all
41
-------
potential pathways. For SLAPS, these pathways are direct exposure
to gamma radiation, inhalation of radon, and ingestion of water
containing radioactivity.
The contribution to the population dose made by gamma radiation fror
on-site radioactive materials is too small to be measured because
gamma radiation levels decrease rapidly as distance from the source
of contamination increases. For example, if the gamma exposure rate
at a distance of 1 m (3 ft) from a small—area radioactive source
were 100 mR/yr, the exposure rate at a distance of 6.3 in (21 ft)
would be indistinguishable from naturally occurring background
radiation. Similarly, radon is known to dissipate rapidly as
distance from the radon source increases (Ref. 18). Therefore.
radon exposure does not contribute significantly to population dcse.
On the basis of radionuclide concentrations measured in water
leaving the site, it also appears that there is no plausible pathway
by which ingestion of water could result in a significant dose to
the population. As water migrates farther from the source, -
radionuclide concentrations are further reduced, lowering potent:al
doses to even less significant levels.
Because the contributions to population dose via all potential
exposure pathways are inconsequential, calculation of dose to the
population is not warranted. The cumulative dose to the population
within an 80.kr (50-mi) radius of SLAPS that results from
radioactive materials present at the site is indistinguishable fro—
the dose the same population receives from naturally occurring
radioactive sources.
3.6 TRENDS
The environmental monitoring program at SLAPS was established to
allow an annual assessment of the environmental conditions at the
site, to provide a historical record for year-to.year comparisons.
and to permit detection of trends. In the following subsections.
1988 annual averages for each monitoring location for radon.
42
-------
external gamma radiation, Surface water, and groundwater are
compared with results for 1984 through 1987 (Refs. 12-15). As the
environmental monitoring program at SLAPS continues and nore data
are collected, comparisons and analyses of trends will become more
meaningful.
3.6.1 Radon
As shown in Table 3-6, overall radon levels remained relatively
constant as compared with 1987 levels. Radon concentrations along
the northern boundary of the site are heavily influenced by soil
moisture and the presence or absence of standing water in the ditch
that abuts the fence line. In 1988, dry weather conditions
moderated slightly, and the ditch contained some standing water
throughout the year. This may account for the slight decrease in
radon levels.
3.6.2 External Ga rma Radiation Levels
As shown in Table 3-7, external gatrma radiation levels at the site
boundary have not demonstrated a significant change since mon1zori ;
began in 1984. Overall, the 1988 external gamma radiation leve:s
remained stable as compared with the 1987 values.
3.6.3 Surface Water
Measured concentrations of radionuc]ides in surface water at SLAPS
have remained relatively stable since 1984 and remain about equai :c
the upstream values. Surface water data for the 1984-1988 period
are given in Table 3-8.
3.6.4 Groundwater
Ten new wells installed in 1986 were added to the groundwater
monitoring program in April 1987. Uranium, radium-226. and
thorjum-230 values for 1987 and 1988 in these new wells are
presented in Table 3-9. Statistical comparisons are made only on
43
I. ’-
-------
TABLE 3-6
ANNUAL AVERAGE CONCENTRATIONS OF RADON-222
AT SLAPS. 1984 1988 a
Sar p1ing
Locatiorib
Concentration
C10
Ci/rnl) .d
1984
1985
1986
1987
1988
1
0.1
0.5
0.4
1.6
1.1
2
0.5
1.2
3.5
3.6
1.2
3
0.3
0.8
0.8
0.7
1.0
4
0.6
0.4
0.9
0.8
1.0
5
0.8
0.6
2.1
2 .
6
0.4
0.5
0.6
0.5
c.
7
0.5
0.7
0.8
0. ’
8
1.0
0.7
1.3
1.8
9
-f
f
3.1
1.0
Backqround
0.5
. 1
0.3
. 1
0.4
-
. .,1
0.4
0.4
5
16c
17 h
181
aData sources for 1984-1987 are the annual site environrrental
reports for those years (ReIs. 12-15).
bsa :ing locations are shown in Figure 3-1.
Cuackground has not been subtracted.
x i0 wCi/ml is equivalent to 1 pCi/i.
eDete: or installed in 1985.
1 Detector installed in April 1987.
‘ ackground detector installed in 1985 in Florissarit. MO.
approximately 24 km (15 mi) northeast of SLAPS.
bsackground detector installed in April 1988 at McDonnell
Blvd., approximately 0.8 km (0.5 mi) east of SLAPS.
1 Background detector installed in April 1988 in St. Charles
County, approximately 32 km (20 m i) southwest of SLAPS.
44
-------
TABLE 3-7
kNNUAL AVERAGE EXTERNAL GAM?4A RADIATION LEVELS AT
SLAPS, 1984 _ 1988 a
Page 1 of 2
Sanpling
Location
Radiation
Level
1984
1985
1986
(mR/yrC
1987
1988
5 9 d
46
14
34
2
2157 d
2087
1363
1557
2128
115 d
116
67
87
10:
4
51 d
57
21
38
38
3
81
67
4E
6
28 d
41
10
35
4
71
43
58
129
12
17
25
38
9
110
129
BackgroU h
16
i
99
97
77
aoata sources for prior years are the annual site environnental
reports for those years (Rels. 12-15).
bsampling locations are shown in Figure 3-1.
CMeasured background has been subtracted frorn the readings
taken at the nine sampling locations shown in Figure 3-1.
dsaitpl ing location installed in late 1984; data are for fourth
quarter only.
•Sampling location established in early 1985.
Location 7 is a quality control for Location 3.
gL.ocation 9 was established in April 1987.
45
-------
TABLE 3-7
(cent inued)
2 of 2
hBackground detector installed at McDonnell Blvd.. approximately
0.8 km (0.5 mi) east of SLAPS, and in St. Charles County.
approximately 32 km (20 mi) southwest of SLAPS. Because the
instruments have been in place for less than 1 year. data will not
be reported until 1989.
1 Background detectors installed in April 1985. Located in
Florissant. MO. approximately 24 km (16 mi) northeast of SLAPS.
46
-------
TABLE 3-8
ANNUAL AVERAGE CONCENTRATIONS OF TOTAL URANIUM.
RADIUM-226, AND THORIUM.230 IN SURFACE WATER
IN THE VICINITY OF SLAPS. 1984 1988 a
Sampling
Locationb
Concentrat
1984
1985
ion
1986
uCi/ml)C
1987
1988
Total Uranium
14.0
4.0
3.4
<3.0
4.3
4.2
4.0
1
2 d
3
<3.0
<3.0
<3.0
4.0
4
...e
<3.0
<3.0
3.5
<4.0
<4.0
4.0
3.0
Pad iurr- 226
3.
0.2
0.2
2 d
0.1
0.1
0.2
0.3
0.4
0.3
3
. e
0.2
0.3
C .s
4
0.1
0.2
0.2
0.3
0.3
0.3
0.2
Thor iu - 230
0.1
1
2 d
0.36
<0.4
<0.2
0.4
0.3
3
...e
<0.5
<0.2
0.2
0.1
4
<0.4
0.3
<0.2
0.3
<0.2
0.3
<0.1
aData sources for 1984-1987 are the annual site environmental
reports for those years (Refs. 12-15).
bsaim .pi ng locations are shown in Figure 3-1.
Cj . x i - i Ci/m1 is equivalent to 1 pCi/i.
dLocation is upstream of the site and acts as background.
Background values have not been subtract.d.
esampling Locations 3 and 4 were added in 1985.
47
\1
-------
TABLE 3-9
ANNUAL AVERAGE CONCENTRATIONS OF TOTAL URANiUM.
RADIUM-226. AND THORIUM-230 IN GROUNDWATER AT
SLAPS. 19841988 a
Pane 1 of
2
Sampling
Location
b.c
Concentration i -
iiCiimljd
1984 1985
1986
1987 1985
Total Uranium
Well A 1287 2375 1184 1139 173C
Well B 5700 4735 6570 5829
Well C 40 36 16 13 19
Well D 233 474 802 637 47 5
Well E 129 114 540 576
Well Fe 141 177 146 106 265
Well MlC-25S — — -— —- 25 35
Well MlO-25D -- —- 4 4
Well Mll-2l -- -- —- 4S 73
Well Ml0-1SS -— -- 11 9
Well M10-1SD —— -- 9 S
Well M10-8S - - —- 32
Well M10-8D -. -- 5 4
Well M11-9 —. 4578 462C
Well Ml3.S-8.5S —- 4 4
Well Ml3.5-8 .SD —- <3
kground t
Well BS3WO1S 3
Well BS3WO1D 4
Radiu r-226
Well A 0.3 0.2 0.3 0.3 0.4
Well B 0.3 0.2 0.3 0.3
Well C 0.3 0.2 0.3 0.4 0.5
Well D 0.2 0.1 0.3 0.1 0.3
Well E 0.6 0.2 0.5 0.3 C 6
Well FC 0.2 0.1 0.2 0.3 2.6
Well Ml0-25S -- — -- 0.2 C 6
Well M10—25D —- —— — — 0.2 0.4
Well M1l—2]. —— —— - — 0.5
Well M10-1SS —— -— — — 0.3 0.5
Well Ml0-1SD —— —— — — 0.4 0.9
Well M10—BS —— —— —- 0.4 0.5
Well M10-8D - - —- - - 0.3 0.6
Well M1l-9 —- -- —_ 0.5 0.8
Well M13.5-8.55 —- -- -- 0.5 0.8
Well M13.5—B.5D -- — - -- 0.5 0.6
48
-
-------
TABLE 3-9
(continued)
P4 __2__of__2
Sampling
Locationb.C
Concentration j -9
] 984
1985
1986
1987
1968
Radium-226 (continued)
--
—-
--
Backpround
Well ES3WO1S
Well BS3WO1D
--
--
--
- -
--
0.6
:.:
Thorium- 230
9.5
2.3
<0.4
0.8
Well A
Well B
0.3
0.3
1.2
1.4
Well C
0.2
0.2
0.2
0.9
Well D
0.9
1.3
0.3
0.9
C. 3
Well E
0.3
1.0
0.4
0.9
Well Fe
0.4
1.).
0.2
1.7
4.8
Well M10-25S
—-
--
—-
0.2
2.C
Well MiD- 25D
--
--
--
<0.8
Well Mil-21
--
.
15.2
Well Mi0-1SS
--
--
—-
1.8
5.3
Well MiD- 1SD
--
“
0.4
Well M10-8S
--
--
—-
0.2
Well MiD-SD
--
——
--
<0.1
0.S
0.3
Well Mll-9
--
—-
—-
03
Well M13.5-B55
- -
--
--
0.4
1.0
Well M135-8.5D
—-
--
—-
<0.1
C.
Ba c k g rou nd f
Well BS3WO1S
--
—-
--
Well BS3WO1D
-.
-.
--
-.
0.2
aData sources for 1984-1987 are the annual site environmental
reports for those years (Refs. 12-15).
b$ampljng locations are shown in Figure 3-1. and background
locations are shown in Figure 1-5.
CThe M M wells were added to the environmental monitoring
program in April 1987.
d 1 x i - uCi/mi is equivalent to 1 pci/i.
•Upgradient well.
SWells established for background in July 1988.
49
-------
the A-F wells because there are insufficient data for analyses of
the M wells (Figure 3-1). As shown in Table 3-9. concentrations of
total uraniun’ in groundwater have remained consistently high .n
wells A and B: in 11-9, which is located approximately 15.2 m
(50 ft) east of well B: and in Ml3.5-8.5 5. Uranium concentrations
in well C remained low over the period 1984-1988. These five wel:s
are located on the western end of the site.
Levels of radiurn-226 and thoriuin-230 have been generally stable at
low levels. An insignificant increase in levels of radium.226 and
thorjum-230 was observed in 1988.
Uraniu- concentrations in groundwater are strongly Influenced by t e
rate at which groundwater moves through the site. For years in
which there is a significant deficit in rainfall and thus a reduced
recharge of the groundwater. uraniui levels can be expected to
rise. Uraniu ’ concentrations observed in certain wells (F and A)
increased fror those measured in 1987.
Though these increases cannot be definitively explained, it is
that wells and E are located adjacent to buried radioactive
materials. Because SLAPS is fenced, the public does not have access
to these wells and there is no known consumption of groundwater in
the vicinity of the site. Based on analytical results for surface
water and hydrogeological studies concerning discharge of
groundwater into Coldwater Creek, there is no evidence that surface
water downstrean of the site has been degraded. Therefore, there :s
no reason to suspect that any member of the public receives an
internal dose of radiation that would approach the DOE radiation
protection standard.
50
-------
4.0 RELATED ACTIVITIES AND SPECIAL STUDIES
4.1 RELATED ACTIVITIES
In April 1987, monitoring of the groundwater for chemical indicator
parameters began at SLAPS. These parameters include pH, Specific
conductance, total organic carbon (TOC). and total organic halide
(TOX). These parameters are indicators of changes in the inorgan:c
and organic composition of the groundwater.
Specific conductance and pH measure changes in the inorganic
composition of the groundwater. Acidity and basicity are measured
by pH. A change in pH affects the solubility and mobility of
chemical contarrinants in groundwater. Specific conductance rreas. :
the capacity of water to conduct an electrical current.
Condu tivity generally increases with elevated concentrations o
dissolved solids. Waters with high saliriities or high total
dissolved solids exhibit high conductivjties.
Groundwater is analyzed for TOC and TOX to determine the organic
content of the water. TOC measures the total organic carbon cor. er.:
of water but is not specific to a given contaminant. TOX measures
organic compounds containing halogens, which are organic corrpour. s
containing fluorine, chlorine, bromine, and iodine.
Table 4-1 lists the ranges of observed concentrations of the fo..r
indicator parameters. Except for specific conductance and the T X
values, all other parameter levels are within the range of the
background wells (BS3WO1S and BS3WO] .D).
The elevated TOX values occurred in wells B. D, and M11-9. No
explanation for these elevated levels is currently available.
However, investigations will be conducted in 1989 to determine the
possible cause.
5 ].
13
-------
St. Loujs MrportJHeIwoodJFij ra Mining Waste NPL Site Summary Report
Reference 6
Excerpts From National Priorities tht Summary Sheet for the
St. Louis Airport/Razeiwood Interim Storage/Futura Coatings Company Site;
EPA; Undated
-------
Nationel Priorities Ust
Superfund hazardous waste site listed under the
Comprehensive Environmental esponse. Compehsatlon and Liability Act (CERCLA) as amer ed In 19
sr. i.aiis
St. Lcvis C ty, Pts. iri
‘Z St. L iis Airp rt/Maze1 Interiir. Storageffiztura Coatings Co. Site
is in St. 1 .045 COzxty, Miss ri. It sists of three areas used for Stor2.ng
r .to tive ard othar wastes resulting fran urar i .mt cessing rati s
c ó. ted in St. La.iiS by t1 * Z ’iic fl rgy C nt issi ( ) &d its strcessor,
t U.S. r r rt of rgy (U X ). of t three areas is r
by t Fe ral GovezTE t.
The St. L iis Airport area covers 21.7 res i iately rcrth of Lairbert
St. Lo.iis Internati a1 Airport, a r dn te1y 3.5 miles zrrtt& t of rrtowr
St. I.oiis. It is by a railroed tr )c, Col iater Creek, aid !t r efl
Bou.levard. R .io tive lietal scr aid dr .rs of waste ware stored in the
a.irport area in t rovered aid iz stabi1ized piles fran 1947 to t mid—1960s,
wt i they ware traiisferred 0.5 mile rcrtleast to ‘S Haze l od Interim
Storage (} S) area. 3.iild.thgs in t a.irport area ware razed, iried, aid
covered with cleart fill after 1967. C4 tai inated soil was r toved to t
ring aiarry in St. C arles CQrzty, Missouri, w?uch was p1 ed c t e
in Ju.ly 1987. In 1969, t1 lard was caiveyed to tha St. Lcuis-Lair ,ert
Airport Aur1 rity.
ICS aid t e Futura Coatings Cc. plairt cover 11 ecres edj rt to Latty
Av • Cold .aater Creek, aid Haii.ley Av n e. l96 C rtii ta.l Mining aid
li lung Co. aquired tr pro rty aid r vera2 uraiüun fran wastes p.ircha.sed
fran Am’s St. Lo.i.is c ratia s. In 1967, tle c aity sold the p u .erty, aid
by 1973 cst processing resi ies t bee raroved. kder the di.rectiai of the
Mrlear Regulatory Catmissian (! ), the prese t rer avated cartairu.r ated
soil aid is storing it in t large piles in tha eastern portion of the 11.
ree. Sixre tIe 19708, Futura Coatings, a z Lf turer of plastic coatix s,
has leased tIe tern portion.
High levels of urai itzn, tI riun, aid r iirt are preseit in aiirf e aid
subsurf e soils aid grazd water rear tI airport area, cording to tests
ca rted by (3976), k Ridge tia a.l La ratory (1977), aid a U E
cattr tor (1986). -222 was presert in tIe air rear tIe a.irp,rt area in
‘tIe U XE tests. A ? ael1 ag1as Corp. office biilding with 24,000
eip1oy is vithin 0.5 mile of tIe airport area.
U XE has investigsted tIe site s r its TOz r1y Utilized Sites Rwed .tal
ctian Pru ,i .z (Ft P). Iii 1982, ti E rted preliminary sti.dies of
ra2.i ti itaninatian of tIe ditcI alag tIe si s of tIe roeds leading
to aid fran the areas. In 1986 • r les ware drilled to ira.e tIe con—
stidy aid collect g 1OgiCal infoz tion. In 1984, U X* cleared
tIe ICS aid Futwa Coatings areas, tr .rted a v iic1e decartanination
f i1ity, ireta.lled a iveter fe e, e avated aid Jth lied tIe edges aid
sI l rs of Latty Avez , aid Eso1idated tIe r i1ting caitaninated soil -S
into ae storage pile. In 1986, ing a city roed iupiuvw t project,
cartaninated soil fran roeds leeding to aid fran all three areas was ccavated.
U p1ai s furthar sttdies In all areas, which ‘411 leed to itiona.1
rd! ia1 tia s.
4 ’
LI S Environmental Protection Agency/Remedial Response Program
-------
St. Louis Airport/Hazeiwood/Futura Mining Waste NPL Site Summary Report
Reference 7
Excerpts From Site Plan for Latty Avenue Properties, Hazeiwood, Missouri;
Prepared for the U.S. Department of Energy by Bechtel National, Incorporated;
November 1989
‘I
-------
‘3
SITE PLAN FOR LATTY AVENUE PROPERTIES
HAZELWOOD, MISSOURI
NOVEMBER 1989
Prepared for
UNITED STATES DEPARTMENT OF ENERGY
OAK RIDGE OPERATIONS OFFICE
Undet Contract No. DE-ACO5 81OR2O722
By
Bechtel National. Inc.
Oak Ridge 1 Tenn..g.e
Bechtel Job No. 14501
-------
Site: Latty Avenue
Prope j
WBS: 140
Date: 10/09/89
II. HISTORY
In early 1966, ore residues and uranium.. and radium_bearing
process Wastes that had been stored at SLAPS were purchased
and moved to a storage sit, on Latty Avenue. These wastes
had been generated by a St. Louis plant from 1942 through the
late 1950s under contracts with the Atomic Energy COmmjssjo
and its predecessor, the Manhattan Engineer District.
Residues on the site at that tim, included 74.000 tons of
Belgian Congo PitChbl,fld, raffinate containing approximately
13 tons of uranium; 32.500 tons of Colorado raffinate
containing roughly 48 tons of uranium; and 8,700 tons of
leached barium sulfate containing about 7 tons of uranium.
The Commercial Discount Corporation of Chicago. Illinois,
purchased the residues in January 1967; much of the material
was then dried and shipped to the Cotter Corporation
facilities in Canon City, Colorado. The material remaining
at the Latty Avenue site was sold to the Cotter Corporation
in December 1969. From August through November 1970, Cotter
Corporation dried some of the remaining residues at the Site
and shipped them to its mill in Canon City. In
December 1970. an estimated 10.000 tons of Colorado raffinate
and 8.700 tons of leached barium sulfate remained at the
Latty Avenue Site.
In April 1974, the newly established Nuclear Regulatory
Commission (NRC) was informed by Cotter Corporation that the
remaining Colorado raffinate had been shipped in mid-1973 to
Canon City without drying and that the leached barium sulfate
had been diluted with site soil and transported to a landfill
area in St. Louis County. Reportedly, 12 to 18 in. of
topsoil had been removed with the leached barium sulfate.
Before the present owner occupied the site, a radiological
characterization was performed by the Oak Ridge National
Laboratory (ORNL) (Ref. 2). Thorium and radium contamination
in excess of DOE guidelines were found in and around the
buildings and in the soil to depths of up to 18 in.
Subsequently, in Preparing the property for use, the owner
demolished Ofli building, excavated portions of the western
half of the property, and paved certain areas in addition to
erecting several new buildings. The material excavated
during these activities (approximately 13.000 yd 3 ) was
piled on the eastern portion of the property.
In 1981. Oak Ridge Associated Universities (ORAU)
characterized the pile and surveyed the northern and eastern
boundaries of the Property for radioactivity (Refs. 3 & 4).
0213N 4
-------
Site: Latty Avenue
Properties
WBS: 140
Date: 10/09/89
Levels of contamination (principally thorium-230) similar to
those on site were found in both areas. As a followup to
this survey, ORNL conducted a detailed radiological survey of
the north and south shoulders of Latty Avenue for DOE in
January and February 1984 (Ref. 5). Results indicated that
contamination in excess of DOE guidelines was present along
the road beyond Hazelvood Avenue. Properties adjacent to
HISS were also found to be contaminated, probably as a result
of flooding, surface runoff, and road and utility line
activities.
The 1984 Energy and Water Appropriations Act directed DOE to
conduct a decontamination research and development project at
four sites throughout the nation, including 9200 Latty Avenue
and properties in its vicinity. Although the contamination
in Hazeiwood did not result directly from the atomic energy
program, the Latty Avenue Properties were added to PUSRAP by
Congress to expedite the decontamination process.
Remedial action activities in 1984 consisted of clearing the
site and selected adjacent properties, constructing the
decontamination facility and installing the perimeter f nce,
excavating and backfilling the edges and shoulders of Latty
Avenue, and consolidating and covering the contaminated soils
storage pile. The 1984 remedial action resulted in the
addition of 14.000 yd 3 of contaminated soil to the HISS
storage pile.
In 1986, a municipal drainage improvement project was
implemented, which included the installation of a storm sewer
along Latty Avenue. As a result of the excavations for sewer
pipe placement, 4,630 yd 3 of contaminated spoils were
placed in HISS in a pile just north of the 27,000 yd 3
stockpile. This brought the total amount of contaminated
material in above grade storage at HISS to approximately
32.000 yd 3 .
In 1985. remedial action activities consisted of Latty Avenue
cleanup, surveying services, material testing, and monitoring
well installation. Work activities started in July 1984 and
were completed in June 1985. Approximately 100 yd 3 of
contaminated soil was excavated at locations along Latty
Avenue and placed on the existing pile.
0213N S
-------
Site: Latty Avenue
Propert ies
WES: 140
Date: 10/09/89
IV. RE DIAI. ACTION
A. Site Characterj2atjon and ScoDing
Radiological and chemical characterization of LAP was
completed in FT 1987. Both MISS and the Futura Coatings.
Inc., properties were characterized. This
characterization included both surface and subsurface
investigations. Monitoring of the environment within the
buildings on the Futura Coatings, Inc., property was
conducted for four quarters.
Routine surveillance and maintenance of the interim
storage area, including environmental monitoring, wi ]]. be
continued. Radiological characterization was completed
along the vicinity properties in 1989.
Analyses of soil samples taken during an NRC
investigation of HISS in 1976 indicated the presence of
uranium- and thorium-bearing residues. Furthermore, at
some areas on the site, direct readings of radiation
exceeded guidelines established by the DOE for
decontamination of land areas prior to release for
unrestricted use.
A radiological characterization of the site was done by
ORNL in the summer of 1977 prior to occupation of the
site by the current owner. At that time, radioactive
contamination in excess of the DOE guidelines was found
in the buildings and over the site from uranium, thorium,
radium, actinium, and their decay products. Sample
analyses indicaced contamination exceeding the guidelines
at various depths down to 45 cm (18 in.).
Characterization of the soil pile on the eastern part of
the sit, was completed in the fall of 1981 by ORAU. In
addition, ORAU performed radiological surveys on the
northern boundary of the site along Latty Avenue and
along the eastern boundary. These surveys showed
elevated levels of the same radionucljd,, that are
present on site.
A surface scan along the north and south shoulders of
Latty Avenue was completed in the summer of 1983 by
ORNL. Th. results of this surface survey indicated that
a formal radiological characterization should be
completed to determine surface limits and depths along
the roadway. This survey was conducted from January 23
to February 4, 1984. It included the City of Berkeley’s
proposed road and storm drain construction area, i.e..
0213N 9
-------
Site: Latty Avenue
Properties
WBS: 140
Date: 10/09/89
the roadway and both shoulders of Latty Avenue.
Additional surveys conducted in March and April 1984
included the site boundaries and surrounding areas.
Bechtel National. Inc. (BNI) initiated engineering
activities to develop the engineering packages necessary
for the radiological/
chemical characterization of 9200 Latty Avenue. These
characterization activities were completed in 1987.
Radiological and chemical characterizations were
conducted in accordance with FUSRAP Project Instructions
and monitoring plans developed for each characterization.
The objective of the characterization was to determine
the vertical and horizontal limits of contamination on
site. Parameters measured included, but were not limited
to, uranium-238, radium—226, thorium—232, ttlorium—230,
and soil and water parameters specified in the Resource
Conservation and Recovery Act (RCRA). All composite
samples were subject to multielement analysis and a total
organic carbon analysis. Results of these analyses were
compared with those made Ofl background soil samples.
In 1987 and 1988, BNI performed a radiological
characterization of the vicinity properties shown in
Figure IV—1. Results from this characterization effort
showed radioactive contamination present on all six
properties. Thorium-.230 was identified as the primary
contaminant. Typically, the contamination is confined to
the top 3 ft of soil.
The radiological characterization indicated contamination
present on HISS to a depth of 6 ft at one location. The
average depth of contamination at HISS is 3 ft.
Contamination is present on the Futura Coatings site to a
depth of 15 ft at one location. Soil sample analyses
indicated elevated levels of uranium-238, radium-226.
thorium-232, and thorium—230. Figures IV-2 and IV-3 show
the areas and depths of radioactive contamination at HISS
and Futura. respectively.
Soil samples collected from the six Latty Avenue vicinity
properties and the Norfolk and Western Railroad property
immediately adjacent to 9200 Latty Avenue were analyzed
for uranium—238. radjum—226 , thortum—232, and
thorium-230. At Property 1. results shoved that depths
of contamination range from the surface to 14 ft.
Typically, the contamination is confined to the top 3 ft
of soil. In general, the areas of contamination are
smaller and fewer relative to greater distances from
HISS.
0213W 10
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FIGURE IV-1 RADIOLOGICAL CHARACTERIZATION OF THE
LATTY AVENUE VICINITY PROPERTIES
1’
p - I
‘a,,!
AVIMI
rD AREAS ( kNO 4 CONIAMINA! ION J
I 0 AREAS OF SUSPECtED CONIAMINAIIONI
I [ J
PROPIRFY BOUNDARY
1141 l/?.IN.N
-------
Site: Latty Avenue
Propert ies
WBS: 140
Date: 10/09/89
V. COST AND SC T!DULE
Estimated costs associated with the portion of work
specifically addressing the LAP during the time period
covered by this plan are listed in Figures v—i and V-2. The
costs shown are in year—of—expenditure dollars The schedule
of work for F? 91 through F? 95 as illustrat.d in Figure V-3
and the text of this plan are based upon current progress and
priorities.
0213W 20
-------
ACTIVITY
FY 90
F? 91
FY92
FY93
FY94
F? 95
BNI
ASSESSMENT
(B&R A}l-I0-05 .01)
-
644
386
216
99
.
CIANUP
(B&R AH-10 .05.02)
640
8.600
600
771
1.016
10.878
SUBTOTAL
640
9.244
986
987
1.115
10.878
ANL
5
25
75
125
100
50
HQ
130
690
55
45
40
330
TOTAL
775
9,959
1,116
1,157
1,255
11.258
N0Th Dollars aie BA
FIGURE v-i LATTY AVENUE PROPERTIES SITE BUDGET
1 1Z1ft14 21
‘9
-------
FY90 DETAIL — LATFY AVENUE PROPERTIES, MO
________ OCTI NOVI DECI JANIFEB IMAR I*p 1 IMAYIJUN IJUL IAUG SEP
PUBLISH
V
p ..
F..
‘140 LATTY AVE.
CHARACTERIZATION REPORT
LEASE HISS PROPERTY
DESIGN & PROCURE
SUBCONTRACT FOR HISS
EXPANSION
PREPARE SCOPING/
PLANNING DOCUMENTS
COMMUNITY RELATIONS PLAN
REMEDIAL INVESTIGATION
REPORT
ENVIRONMENTAL MONITORING
FUSRAP
ANL
HO
TOTAL ($000-BA)
DOE RE VIEW DRAFT
DOE REVIEW DRAFT V
DOE REVIEW DRAFT V
71
49
63
57
66
58
78
40
39
39
40
40
—
—
—
—
—
1
1
1
1
1
—
—
11
11
11
11
11
11
11
11
11
11
10
10
82
60
74
68
77
70
90
52
51
51
50
50
FIVE YEAR PLAN FY90 VS FY90 BASELINE RECONCIUATION THE ft 111S PROCESS HAS BEEN ACCELERATED AND STARTED IN FY09 AND WILL CONTiNUE IN
FY90 ORIGINALLY FY90 PLANNED ACTIViTIES FOR THIS SITE WERE INCLUSIVE TO SUR 1 VEILLANCE AND MAINTENANCE ACTIVITiES
PROPOSED MILESTONES CONTROLLED BY DOE HO V ORO TSD 0 PMC Q ANL
b9 1141 I?
r-srs sri , i ,— , rir r q—-r a as
-------
4.
LAITY AVENUE PROPERTIES — 5YEAR PLAN
FY91
FY92
FY93
1
2
3
4
1
2
3
4
1
2
3
4
1
FY94
2J3
FY95
ASSESSMENT
SIGN
R I/FS - EIS
CLEANUP
ACQUIRE HISS
—
—
—
—
EXPAND HISS (FOR RECEIPT OF
WASTE FROM SLAPS V.P.)
CLEANUP VICINITY PROPERTIES
ENVIRONMENTAL MONITORING
(
>
—
—
—
—
—
—
—
—
—
—
ANNUAL
REPO
IflS
— —
*1
Sig 11)1 14
9/20/89
FIGURE “-3 FY 91 -95 SCHEDULE
-------
Mining Waste NPL Site Summary Report
Sulphur Bank Mercury Mine
Lake County, California
U.S. Environmental Protection Agency
Office of Solid Waste
June 21, 1991
FINAL DRAFT
Prepared by:
Science Applications International Corporation
Environmental Health Sciences Group
7600-A Leesburg Pike
Falls Church, Virginia 22043
-------
DISCLAIMER AND ACKNOWLEDGEMENTS
The mention of company or product names is not to be considered an
endorsement by the U.S. Government or by the U.S. Environmental
Protection Agency (EPA). This document was prepared by Science
Applications International Corporation (SAIC) in partial fulfillment of
EPA Contract No. 68-W0-0025, Work Assignment Number 20. A
previous draft of this report was reviewed by Carolyn d’Almeida of
EPA Region IX [ (415) 744-2225], the Remedial Project Manager for
the site, whose comments have been incorporated into the report.
-------
Mining Waste NPL Site Summary Report
SULPHUR BANK MERCURY MINE
LAKE COUNTY, CALIFORNIA
INTRODUCTION
This Site Summary Report for Sulphur Bank Mercury Mine was developed as one of several National
Priorities List (NPL) Site Summary Reports and will be used to support EPA mining waste program
activities. In general, these reports summarize the types of environmental damages and associated
mining waste management practices at sites on (or proposed for) the NPL as of August 30, 1990 (55
Federal Register 35502). Each summary report is based on pertinent information gathered from EPA
files and reports, and on a review of the summary by the EPA Region LX Remedial Project Manager
for the site, Carolyn d’Almeida.
SITE OVERVIEW
Sulphur Bank Mercury Mine is located in Lake County, California, on the eastern shore of the Oaks
Arm of Clear Lake (see Figure 1). Mining has occurred at the site intermittently since 1865 and has
involved sulphur and mercury mining (Reference 1, page 4). The site consists of approximately 120
acres of mine tailings and waste rock, a partially dismantled mill facility, and an open, unlined, and
unstabiized mine pit referred to as the Herman Pit, or Herman Impoundment. An earthen dam was
constructed at the west end of the pit in 1979, with a design capability to withstand overflow from a
200-yeax flood. Prior to dam construction, water from the pit would overflow into Clear Lake
seasonally and during large magnitude storm events (Reference 2, page 12). The pit, which is located
about 700 feet east of Clear Lake (see Figure 2), covers approximately 23 acres and is filled with
water to a depth of up to 90 feet (Reference 1, page 4; Reference 2, page 3).
Mercury cOnt2rninalion of biota, surface water, and sediments has been found in the vicinity of the
site (i.e., the Oaks Arm of Clear Lake). Although mercury is the main contaminant of concern,
significant levels of arsenic are present in surface-water mine discharges and Oaks Arm bottom
sediments (Reference 2, page 18; Reference 4, page 2). In May 1986, the State of California issued
public health advisories recommending restrictions on consumption of fish from Clear Lake due to the
levels of mercury detected (Reference 2, page 4).
Based on the nature and distribution of the contamination, EPA has designated three Operable Units at
the site. These include Herman Impoundment; waste piles and contaminated soils; and lake sediments
in Oaks Arm of Clear Lake (Reference 2, page 1).
1
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Sulphur Bank Mercury Mine
3
SCAIl IN MI 11
FIGURE 1. SULPHUR BANK MERCURY MINE LOCATION
*
$
•33.S
CI...i.k. Osks
K MINE
N
I
24”
2 6 ’
30”
2
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Mining Waste NPL Site Swnmary Report
-
Oaks Ar of Clear Lake . •••••“ •.:
— I -
— ‘ r ‘ / Y r 7 -/2 ’
__ ___ __
i z i -‘ LrJi
0
SCML rsz000
7ig ar. 2. C.nua1 Sits Lacsct.n Kap.
FIGURE 2. GENERAL SITE LOCATION MAP
2000
*000
4000
3
-------
Sulphur Bank Mercury Mine
The Sulphur Bank site was proposed for the NPL in June 1988, with a Hazard Ranking System score
of 46.59 (53 Federal Register 23988; June 24, 1988). The proposed listing was based mainly on a
perceived threat to the City of Clear Lake Oaks’ ground-water supply wells (currently serving
approximately 4,700 people). The NPL site proposal was also based on the fact that the State of
California does not have an approved program under the Surface Mining Control and Reclamation
Act (SMCRA) of 1977, making the site ineligible for SMCRA reclamation funds.
On August 22, 1988, the only “surviving” Potentially Responsible Party (PRP) identified to date,
Bradley Mining Company (BMC), protested the listing proposal on the grounds that the primary
source of mercury, arsenic, and other inorganic substances in both Herman Lake and Clear Lake is
from natural geothermal activity and not surface runoff from mining waste. It also argued that the
releases, which it claimed were occurring naturally, have not contaminated public drinking-water
supplies and did not threaten to do so (Reference 3, pages 1, 3 and 30). Despite this opposition, the
site was placed on the NPL on August 30, 1990.
Enforcement actions and investigations at the site have progressed as described here. The Central
Valley Regional Water Quality Control Board (RWQCB) has been the lead agency in addressing the
site contamination. In 1983, the Clear Lake Mercury Task Force was set up to address public and
regulatory concerns that arose from “hundreds” of mercury-contaminated fish samples collected in the
late 1970’s and early 1980’s. It consisted of representatives from the California Departments of
Health Services (DHS) and Fish and Game, RWQCB, the Elem Indian Reservation, and several other
county and local concerns (Reference 2, page 4). In 1985, a Preliminary Site Assessment was
completed by Columbia Geoscience for the BMC. In 1987, as required under the California Toxic
Pits Clean-up Act (IPCA), BMC conducted a study addressing contaminants in the Herman
Impoundment (Reference 6). In 1989, DHS determined that as long as the sediments remain at the
bottom of Herman Impoundment they might not be considered as hazardous waste, but if removed,
the sediments would be a State-regulated hazardous waste (Reference 2, pages 4 and 5).
Phase One of the Hydrogeological Assessment Report (which addresses onsite ground-water
characterization) was completed by Columbia Geoscience for BMC in 1988. Several monitoring
wells were drilled, water samples were collected, and field tests were conducted to determine aquifer
characteristics. An ongoing ground-water monitoring program is part of the Hazard Ranking System
study. Phase II and Phase ifi reports were submitted by Columbia Geoscience in 1989 and 1990,
respectively (Reference 2, page 5).
In addition, researchers from Humboldt State University completed a study for the RWQCB on the
source of mercury and arsenic contaminants in Clear Lake (Sulphur Bank Mine was identified as the
primary source) and on methods to control further contamination of the Lake. This study (Abatement
4
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Mining Waste NPL Site Summary Report
and Control Study: Sulphur Bank Mine and Clear Lake) was completed and submitted to the
RWQCB in January 1990 (Reference 1, pages ix and 2; Reference 2, page 5).
In February 1990, the RWQCB issued Waste Discharge Requirements to BMC regarding the Sulphur
Bank Mercury Mine site. Under the Water Discharge Requirements, BMC will implement, with EPA
oversight, erosion control measures over a 5-year period. The Water Discharge Requirements do not
address the contamination present in Clear Lake sediments (Reference 2, page 5).
OPERATING HISTORY
Prior to mining, the Sulphur Bank site consisted of various hot springs surrounded by thick surface
deposits of native sulphur. The California Borax Company began removing sulphur from the surface
pits in 1865. The sulphur was transported by rail to a refinery where the ore was liquifled to drive
off impurities, then cooled and shipped. Mine operations ceased in 1871 when market prices
decreased and when increasing impurities increased refinery costs. Approximately 1,000 tons of
sulphur were produced from 1865 to 1871 (Reference 2, page 3).
In 1872, California Borax Company reopened the mine for mercury ore production. The ore was
mined from the Herman shaft at a depth of 450 feet. Approximately 3,200 tons of mercury were
produced by the time California Borax ceased operations in 1883. The Sulphur Bank Quicksilver
Mining Company began mining in 1887 by sinking two new shafts, the Diamond and Babcock shafts
(about 640 and 710 feet deep, respectively). The Sulphur Bank Quicksilver Mining Company
removed 400 tons of mercury by the time the operation was closed in 1897. The Empire
Consolidated Mining Company assumed ownership in 1899, and operated until 1906. The three
previous shafts collapsed and the new owners sank two new shafts, the Empire shaft and the Parrot
shaft (about 610 and 730 feet deep, respectively). Underground mining operations ceased in 1905
because of extreme heat and gas. About 20 tons of mercury were produced during these years
(Reference 2, page 3).
Mining resumed at the site in 1915, when the Sulphur Bank Association of San Francisco began open-
pit mining. Operations ceased in 1918; between 1915 and 1918, 80 tons of mercury were produced.
The BMC began open-pit operations at the site in 1927 under a lease from the G. T. Ruddock estate.
It also sank two new shafts, which subsequently caved in by 1944. By the time BMC ceased
operations in 1945, approximately 1,200 tons of mercury had been produced. At the conclusion of
BMC’s operations, the pit filled with precipitation and runoff, forming the Herman Impoundment.
Ten years later, in 1955, BMC owned the mine. It drained Herman Impoundment and resumed open-
pit mining. During this final production phase, BMC removed 120 tons of mercury. Mine
5
-------
Sulphur Bank Mercury Mine
operations ceased in 1957, and the pit filled with precipitation and runoff again, forming the existing
Herman Impoundment (Reference 2, pages 3 and 4).
Sulphur Bank was one of the largest producers of mercury in California with an estimated total
production ranging from 4,400 to 7,000 tons. Between 1865 and 1945, an estimated 1,250,000 tons
of material were removed, processed, and disposed at Sulphur Bank (Reference 1, page 4).
Both mining activities and natural sources have caused mercury deposition in Clear Lake. Recent or
current sources of mercury contamination include:
• Shoreline erosion of steep slopes made of tailings and waste rock; sheetwash erosion from
the banks; and/or slope failures from undercutting of the slope by lake waves. Mercury
concentrations measured in the Humboldt study averaged 158 parts per million (ppm);
mercury loadings from this source were estimated at greater than 132 kilograms (kg) per
year in 1988 and 1989 (which were dry years, so the average may be higher).
• Fluvial transport (as drainage from the rest of the mine site) of mercury-contaminated
sediments to the Oaks Arm. The possibility that the Herman Impoundment Dams might
fail is of particular concern (and has to be addressed under the RWQCB order). Water in
onsite peripheral streams contained mercury at 330 to 490 parts per billion (ppb) in 1989.
The Humboldt study estimated the average mercury load in drainage as 1.24 to 18.6 kg of
mercury per year.
• Ground-water transport from Herman Impoundment to the Lake.
• Air transport of mercury vapor and/or mercury-contaminated particulates (Reference 2, pages
20 through 22).
Historical sources, in addition to those listed above, included:
• Mercury from mine water and sludge pumped into the Lake during open-pit mining operations
• Airborne mercury from ore smelting
• Disposal of overburden and mercury tailings from ore smelting (Reference 2, page 18).
6
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Mining Waste NPL Site Summary Report
Natural mercury inputs from active hydrothermal (high-temperature water) sources have also been
documented in the Sulphur Bank vicinity (Reference 1, pages 10 and 11). Deeper sediments in Clear
Lake also contain high mercury concentrations, the result of natural sources prior to mining
(Reference 2, page 18). For example, there is a mercury peak at a depth of about 4 meters. These
sediments were deposited about 6,000 years ago.
In the 1990 study done by Humboldt State University for the RWQCB, it was concluded that sheet-
wash erosion and slope failures deliver approximately 100 kg of mercury into Oaks Arm annually;
fluvial transport contributes about 10 kg; and ground-water sources deposit less than 1 kg per year.
Sulphur Bank Mine was found to be the most significant source of mercury entering the Oaks Arm of
Clear Lake.
SITE CHARACIERIZATION
Mining Wastes
Waste generated at the site consists of waste-rock piles and tailings piles. The waste-rock piles
contain overburden and barren rock that were removed from the mine shafts and open excavations
from 1865 to 1957. The excavated, barren, waste-rock piles occupy about 90 acres of land at
Sulphur Bank. The tailings piles, derived from milled and roasted ore-bearing rock from which
mercury was extracted, cover about 17 acres (Reference 5, page 36). There is a minimum of
193,600 cubic yards of wastes onsite (Reference 2, page 17). The distribution of these wastes at the
site is presented in Figure 3. Both mercury and arsenic concentrations in these materials are elevated.
RWQCB samples (in 1983 and 1984) showed mercury concentrations from 1 to 624 milligrams per
kilograms (mg/kg). Humboldt later found an average mercury concentration of 158 ppm. Although
arsenic in wastes has not yet been adequately characterized, RWQCB’s data also showed arsenic
levels of up to 140 ppm (Reference 2, page 17).
Surface Water
The Clear Lake Watershed is approximately 1,370 square kilometers (km 2 ) and Clear Lake itself is
approximately 178 km 2 (Reference 1, page 5). The Sulphur Bank site is bounded by the Oaks Arm of
Clear Lake to the north and west. Most of the year’s precipitation occurs between September and
April, and ranges from 56 to 165 centimeters per year depending on elevation and location within the
basin (Reference 1, page 5). Lake outflow is through the west arm of the Lower Lake forming the
headwaters of Cache Creek, which drains into the Sacramento River.
1
-------
Sulphur Bank Mercury Mine
I I -— - .-u.----.-----— \
R.4
N )
- t .... . • _ •%••
j
‘V
;
.‘ .. S ... •I 4. ..
0’ -
. .c 1?r1 .: ..m to ir
r I i
: pt.rL, I .j:W: : fl _______
__ ___ -
—
PMw Ovs WU ft
-_
Qa
C .aasiftcattOfl aud Spacta 1.
DLsC tbuCiDfl of Mm. W.it..
ac Si&1p u B k Mtns
USEPA Stts Ma a$.*m t
Pun Ja nuaZ7 1990
FIGURE 3. CLASSIFICATION AND SPATIAL DISTRIBUTION OF MINE WASTES
AT SULPHUR BANK MINE
- - MmllhI!RfmIIu . uH1IIflhIImhI1 4gI
r —
QOi&
Figur. 3
8
o s
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Mining Waste NPL Site Summary Report
Clear Lake is classified as “eutrophic to highly eutrophic” and is thermally stratified for only short
periods in the summer (ranging from a few hours to a week). The Lake is ranked as one of the most
productive sport fisheries in California, and supports over 300,000 angler days per year (Reference 1,
page 5). (Results of sampling conducted on fish in the Lake are discussed below with environmental
damages and risks). The pH of the lake is high, ranging from 7.5 to 9.0 (Reference 5, page 23).
Steeply sloped tailings and waste-rock piles extend into the Lake and are in contact with about 2,060
feet of shoreline. Runoff from these piles drains into Clear Lake. In addition, wave activity from
storms results in erosion at the base of the piles (Reference 2, page 13).
Researchers from Humboldt State University collected water-column samples from four locations in
the Oaks Arm region of Clear Lake from February 1988 to March 1989 (Reference 1, page 193). In
the 1990 report to RWQCB, the researchers found no consistent pattern in depth or season for
evidence of mercury in the water column. The average mercury concentration based on 40 samples
was 1.0 micrograms per liter (jtgll) with a standard deviation of 2.1 g/l. However, when two
outliers were removed from the sample (both more than 3 standard deviations larger than the mean),
the average mercury concentration was 0.5 igfl with a standard deviation of 0.3 g/l (Reference 1,
page 79). As noted, water in peripheral streams that drain the mine site and discharge to Oaks Arm
of Clear Lake contained mercury concentrations of 330 to 490 ppb (jig/l) in 1989 (Reference 2, page
21).
Herman Impoundment, fonned in the mine pits, has water levels several feet above the surface of
nearby Clear Lake. It contains about 700 acre-feet of water and is up to 90 feet deep in some areas.
Prior to construction of an earthen dam in 1979, overflow into Clear Lake from the Impoundment
occurred seasonally and during large storm events. The source of water is primarily infiltrating
ground water and drainage from 88 acres of the mine site (Reference 2, page 12).
Herman Impoundment also contains high concentrations of sulfate, sodium, chloride, boron, and
ammonia. Large volumes of geothermal gases (carbon dioxide, methane, nitrogen, and hydrogen
sulfide) continuously boil through the oxygen-rich water, creating a highly reactive environment
(Reference 5, pages 24 and 25).
The Impoundment is a unique water body, very acidic (with a pH of about 3.0, the result of natural
geothermal and chemical activity) and with elevated trace metals. The unusual geochemical nature of
Herman Impoundment sediment and waters is the combined result of diverse sources, including:
9
-------
Sulphur Bank Mercury Mine
• Discharge of natural geothermal fluids and gases
• Erosion of sediment from waste rock and tailings
• Discharges of meteoric water in contact with waste rock and tailings
• Chemical reactions between impoundment water and pit wall-rock (Reference 2, page 12).
“The major source of mercury in the pit sediments was likely associated with detrital accumulation
from site surface runoff. Less significant contributions may be attributed to pit-wallrock reactions and
precipitation from geothermal fluids entering the bottom of the pit” (Reference 2, page 15).
In 1987, Columbia Geoscience conducted a study for the PRP (BMC), to comply with the
requirements for the California TPCA. In this study, water samples from Herman Impoundment
were found to be below the toxic limits specified in the TPCA (Reference 6, page 1). According to
this study, the average mercury concentration from nine samples taken in Herman Impoundment
ranged from 0.0038 to 0.00025 milligrams per liter (mgll), with an average of 0.00081 mg/l. One
sample exceeded the EPA Maximum Contaminant Limit Drinking Water Standard (DWS) of 0.0020
mg/I of mercury (Reference 6, page 22; Reference 5, page 25). However, two filtered water samples
from the impoundment contained 1.3 and 0.75 ig/l of mercury, which exceed EPA’s No-Adverse-
Response Level of 0.144 tg/l and the Ambient Water Quality Standard of 0.012 ig/l for fresh-water
aquatic life. Pit water also exceeds DWSs for cadmium and Ambient Water Quality Criteria for
fresh-water aquatic life for beryllium, copper, nickel, and zinc (Reference 2, pages 15 and 16).
Sediments
Mercury concentrations from bottom sediments in the Oaks Arm portion of Clear Lake range from 11
to 250 mg/kg, with an average of 80 mg/kg. This compares to the State action level for mercury in
sediments of 20 mg/kg. Bottom sediments in the rest of Clear Lake ranged from not detected to 12
mg/kg, with an average of 2 mg/kg. High levels of mercury were found in the upper 50 to 60
centimeters of sediment, which corresponds to the last 100 years of lake deposition (i.e., during the
period of mining) (Reference 2, pages 17 and 18).
Much of the mercury in Oaks Arm is in the upper sediments, about 100,000 kg, as compared to about
440 kg in the sediments blanket and 60 kg in the water column. Mining practices “appear to be the
most likely source for mercury” (Reference 2, pages 17 and 18).
10
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Mining Waste NFL Site Summary Report
High arsenic levels have also been detected in the bottom sediments of the Oaks Arm portion of Clear
Lake. Concentrations ranged from less than 5 to 95.9 mg/kg, with an average of 27.9 mg/kg
(Reference 2, page 18).
Data from the study of Herman Impoundment performed by Columbia Geoscience also showed that
the sediments of the Oaks Arm portion of Clear Lake and Herman Impoundment contain elevated
levels of mercury. However, the study concluded that high mercury levels have been present in the
sediments of Clear Lake for thousands of years. Columbia Geoscience further concluded that the data
also showed that mercury is not leaching into Herman Impoundment from the sediments or adjacent
rock. Additionally, it contends that mercury-bearing geothermal water and gas continued (through
1987 - the date of the study) to be discharged into Clear Lake and Herman Impoundment. Finally, it
provided volume calculations in an attempt to show that erosion from the mine cannot account for the
near-surface, mercury-rich sediments in the Oaks Arm portion of Clear Lake (Reference 6, page 40).
A primary concern for the Lake Sediments Operable Unit is the bioaccumulation of mercury in the
food chain and, potentially, the human population; this occurs when inorganic mercury in Oaks Arm
sediments (and possibly the water column as well) is biologically converted (by microorganisms in
water and/or sediments) to its methylated form. Methyl mercury, in turn, is assimilated by fish and
bioaccumulated (and concentrated). Many factors influence the methylation process, including
speciation of the inorganic mercury (e.g., elemental or ionic); dissolved oxygen content of water;
temperature; (a measure of ionization potential); pE; pH; type and concentration of bacteria present;
and type and concentration of complexing ligands and chelating agents (Reference 2, pages 22
through 27, 30 and 31). Critical to the process of evaluating and selecting remedies for sediment
contamination will be an understanding of the significance of Sulphur Bank as a source of bioavailable
mercury in the Lake (Reference 2, page 45), and of the other factors that influence or control methyl
mercury production in Clear Lake and its sediments (Reference 2, page 25).
Ground Water
Ground-water contamination has been characterized by data collected from onsite and offsite wells.
Three monitoring wells exist at the site. No domestic-water wells are known to have detectable levels
of mercury (Reference 2, page 18). Columbia Geoscience reported that the mercury level in an
unused onsite BMC well was 0.2 ig/1 (Reference 2, page 19). Researchers from Humboldt State
University found (unfiltered) mercury concentrations from one sample site to range from 7 to 130
zg/l. Analysis of two filtered samples from one monitoring well were 0.4 and 0.6 g/l of mercury;
the other two monitoring wells’ samples measured 15 and 60 g/l. The research team considers the
sampling results suspect because of improper filtration (Reference 2, pages 18 through 26).
11
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Sulphur Bank Mercury Mine
The Herman Impoundment receives shallow ground-water seepage from the north, east, and south.
Seepage from Herman Impoundment migrates westward to Clear Lake (Reference 5, page 43;
Reference 2, page 19). The amount of mercury being transported via ground water from Herman
Impoundment to Clear Lake is dependent on the elevation difference between the two water bodies,
the hydraulic conductivity of the aquifer, and the mercury content in ground water. Compared to
erosion of shoreline sediments, Herman Impoundment’s contribution of mercury to Clear Lake via
ground water is considered very low (Reference 2, page 19).
No domestic, stock, or public water-supply wells are located downgradient of the Sulphur Bank mine
site. Nearby wells showed mercury at, or below, detection limits (sampling data were not provided)
(Reference 2, page 19).
Air
The air migration pathway has not been evaluated to date. A mercury vapor survey by RWQCB (in
1988) found vapor concentrations well below the 0.05 milligrams per cubic meter exposure limit (10-
hour time-weighted average) recommended by the National Institute of Occupational Safety and
Health. Indoor mercury concentrations have not been measured in the onsite caretaker’s residence or
several homes in the Elem community, which are constructed on mine tailings. Nor have onsite or
offtite particulate concentrations been measured (Reference 2, page 22).
ENVIRONMENTAL DAMAGES AND RISKS
Elevated levels of mercury were first detected in Clear Lake in 1970 by the California DHS. Since
then, samples from fish and water fowl and from sediments and water in the vicinity of Sulphur Bank
Mercury Mine and the Oaks Arm of Clear Lake have been analyzed for mercury. Data from these
samples indicate that the highest levels of mercury are found in the Oaks Arm portion of Clear Lake
in the proximity of the Sulphur Bank Mine (Reference 1, page 11).
In fish and bird populations, mercury concentrations from 0.1 to 10 ppm are common. Mercury rates
in fish ranged from 0.07 to 1.5 mg/kg (fresh weight) while mercury rates in Grebe populations
ranged from 0.4 to 9.8 mg/kg (fresh weight). Concentrations of mercury in fish sometimes exceed
the Food and Drug Administration limit of 1.0 ppm and often exceed the National Academy of
Science level of 0.5 ppm established to protect fish and predator species that consume fish (Reference
1, page 11).
12
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Mining Waste NPL Site Summary Report
In 1983, the Clear Lake Mercury Task Force was formed due to growing public and regulatory
concern about the site. Toxicological studies addressing mercury in fish from Clear Lake were
conducted by DHS. As a result of these studies, guidelines for human consumption of fish
contaminated with methyl mercury in Clear Lake were issued in May 1986 and in April 1987. In
May 1986, the State of California issued health advisories recommending restrictions on fish
consumption due to the levels of mercury detected in Clear Lake fish (Reference 2, page 4).
REMEDIAL ACTIONS AND COSTS
To date, no remedial actions have been taken under Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA). However, BMC has been ordered by RWQCB to take
several actions to control sources of mercury contamination from the waste piles and Herman
Impoundment (Reference 2, page 32). Table 1 presents the primary environmental concerns
associated with each of the three Operable Units and possible remedies to address these concerns.
CURRENT STATUS
The site was placed on the NPL on August 30, 1990. EPA Region IX recently completed the interim
final work plan for the Remedial Investigation/Feasibility Study (Reference 2). The tentative schedule
calls for the work plan to be made final by the summer of 1991; the Records of Decision (ROD)
should be finalized for two of the Operable Units (Herman Impoundment and Mine Waste Piles) in
the winter of 1993-1994. A ROD for the Lake Sediments Operable Unit should be complete by the
winter of 1994-1995 (Reference 2, Appendix I, page 1).
I’ 13
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Sulphur Bank Mercury Mine
TABLE 1. PRIMARY CONCERNS AND POTENTIAL REMEDIES FOR SULPHUR BANK
NFL SiTE
Operable
Unit
Primary
Concerns
Possible
Remedies
Herman Impoundment
•
Human/ecological direct contact with
acidic pit water
• No action
•
Potential surface- and ground- water
discharge of acid and metals into
Clear Lake
• Neutralizing acid waters (by
liming)
• Draining aixi plugging the pit
• Rerouting ground-water flow
with barners
Mine Waste Piles
•
Physical hazards
To be accomplished by BMC under
RWQCB order:
•
Potential soil ingestion by children
playing onsite
• Rip-rapping shoreline
•
Potential ingestion of tules, wild
berries, or garden vegetables
growing onsite or in adjacent areas
with mercury-contaminated soils
• Constructing toe buttress on
waste piles to stabilize slope
• Mmtmii’ing erosion with gully
work
•
Possible air exposure to mercury and
arsenic vapor arid particulates
• Improving dam
•
Continued erosion of mine waste
into Oaks Arm of Clear Lake
Potential additional remedies:
• Cutting back sloped piles along
shoreline
.
• Capping (with clean soil) and
revegetating piles
• Onsite rebunal of wastes in the
pit
• Growing, covering, solidifying,
and/or vitrifying waste piles
Lake Sediments
•
Methyl mercury production and
bioaccumulation
• No action
• Dredging some or all sediments
Source: Reference 2, pages 31 thou
• Covering some or all sediments
with clean sand or clay
gh 33 and 40 through 45
14
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Mining Waste NPL Site Summary Report
REFERENCES
1. Abatement and Control Study: Sulphur Bank Mine and Clear Lake; Charles Chamberlin et aL;
Prepared for the California Regional Water Quality Control Board by Humboldt State University;
January 1990.
2. Work Plan for the EPA Region IX In-house Remedial InvestigationfFeasibility Study, Sulphur
Bank Mercury Mine Site: Interim Final; EPA Region IX; April 1991.
3. Comments of Bradley Mining Company in Opposition to the Proposed Listing of the Sulphur
Bank Mine on the NPL; Anthony 0. Garvin, Landels, Ripley & Diamond; August 22, 1988.
4. Memorandum Concerning Special Study Waste Support Documentation; From Scott Parish, EPA,
Office of Solid Waste and Emergency Response; Hazard Ranking and Listing Branch; May 17,
1988.
5. Hydrogeological Assessment Report, Sulphur Bank Mercury Mine, Clear Lake, California;
Prepared for Bradley Mining Company by Columbia Geoscience; July 1988.
6. Herman Lake TPCA Assessment, Sulphur Bank Mercury Mine, Lake County, California;
Prepared for Bradley Mining Company by Columbia Geoscience; 1987.
-------
Sulphur Bank Mercury Mine
BIBLIOGRAPHY
EPA. NPL for Uncontrolled Waste Sites, 55 Federal Register , pages 35502-35525.
August 30, 1990.
EPA Region IX. Work Plan for the EPA Region IX In-house Remedial Investigation/Feasibility
Study for SuiphurBank Mercury Mine Site: Interim Final. December 1990.
Garvin, Anthony 0. (Landels, Ripley & Diamond). Comments of Bradley Mining Company in
Opposition to the Proposed Listing of the Sulphur Bank Mine on the NPL. August 22, 1988.
Parish, Scott (EPA, Office of Solid Waste and Emergency Response, Hazard Ranking and Listing
Branch). Memorandum Concerning Special Study Waste Support Documentation to the Hazard
Ranking System Package. May 17, 1988.
Prepared For Bradley Mining Company by Columbia Geoscience. Herman Lake TPCA Assessment,
Sulphur Bank Mercury Mine, Lake County, California. 1987.
Prepared For Bradley Mining Company by Columbia Geoscience. Hydrogeological Assessment
Report, Sulphur Bank Mercury Mine, Clear Lake, California. July 1988.
Prepared For California Regional Water Quality Control Board by Charles Chamberlin et al.
(Humboldt State University, Arcata, California). Abatement and Control Study: Sulphur Bank
Mine and Clear Lake. January 1990.
-------
Sulphur Bank Mercury Mine Mining Waste NPL Site Summary Report
Reference 1
Excerpts From Abatement and Control Study: Sulphur Bank Mine and Clear Lake;
Charles Chamberlin et al.; Prepared for the California Regional Water Quality Control Board
by Humboldt State University; January 1990.
0 ’
I’
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0
Abatement and Control Study:
Sulphur Bank Mine and Clear Lake
Contract No. 7-703.150.0
Prepared for
California Regional Water Quality Control Board
Central Valley Region
3443 Routier Road, Suite A
Sacramento, CA 95827-3098
Prepared by
Dr. Charles E. Chamberlin
Dr. Ronald Chaney
Dr. Brad Finney
Ms. Misti Hood
Dr. Peter Lehman
Dr. Mac McKee
Dr. Robert Willis
Environmental Resources Engineering Department
Humboldt State University
Arcata, CA 95521
January 1990
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Executive Summary
This report details the procedures, findings, and recornmendauons of a source
coiurol and polluuon abatement study of the mercury contamination problem in Clear Lake,
California, The project has sought to identify the eritical mercury sources, understand the
mercury nansport processes that are most important, and design and evaluate connol and
abatement snaxegies that are most promising. The major sections of the report deal with:
(1) mercury discharges from the Sulphur Bank Mine (SBM); (2)the calculation of a
mercury balance for the Oaks Arm of the lake, including the identification of the principal
inputs and outputs of mercury and the amounts of mercury contained in the waters,
sediments, etc.; (3) an analysis of source coiurol snaregies for limiting the rate at which
mercury enters the lake; (4) an analysis of pollution abatement srngies for dealing with
the quanunes of mercury that are presently in the lake; and (5) recommendations.
The principal findings may be summarized as follows:
Mercury Sources and Transport:
1. The most significant source of mercury entering the Oaks Arm of Clear
Lake is the Sulphur Bank Mine.
2. Shoreline ansport of soil materials through sheet-wash erosion and slope
failures represent the largest conthbuuon of mercury to the Oaks Arm. This
delivers approximately 100kg of mercury per year, in conuast to fluvial
nansport and groundwater sources, which conthbute approximately 10 and
less than 1 kg of mercury per year, respectively, to the Oaks Attn.
3. Of the mercury already in the Oaks Arm, the largest amount (about
100,000kg) is in the upper sediments, while the sediment blanket and the
water column account for much smaller quantities of mercury (respectively,
440kg and 60kg).
4. The most significant outputs of mercury from the Oaks Arm are losses into
the sediments. This amounts to approximately 100kg of mercury per year.
Losses to the atmosphere and flows our of the Oaks Aim each account for
approximately 10kg per year.
5. Historically, mining practices that have disposed of waste rock and surface
overburden directly into the lake during the periods of 1927-44 and 1955-57
appear to be the most likely source for the mercury stored in the upper
sediments of the Oaks Arm.
Source Control Strategies:
6. For greatest effectiveness, source conool suategies should focus first on
reducing raves of shoreline erosion and then on fiuvial transport
mechanisms.
7. Twelve source connoj suategies were targeted for detailed examinauon, and
various combinations of these suategies were evaluated on the basis of
ix
, 0
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magnitude of mercury transport via groundwater, it would be necessary to
develop a groundwater flow model for the aquifer involved. In other cases.
applicable control and/or abatement experience from other sites with mercury
contamination were used.
3. Data Analysis and Report Preparation
The results of the data collection program and the detailed assessments were
analyzed and are presented here in this final report. A range of source control
and pollution abatement measures axe described that would provide a gradation
of control and abatement levels and costs.
Following a brief description of the context and history of the current problem in
Section II, the eswnaxed current mercury discharges into Clear Lake from the SBM will be
discussed in Section ifi and a mass balance for mercury in the Oaks Arm and Clear Lake as
a whole will be developed in Section IV. This section will also cover esnm r s of historical
loadings from the mine site. Sections V and VI will outline and evaluate source control
strategies for the SBM site and pollution control strategies for mercury contamination in the
Oaks Arm. Finally, Section VU will present recommendations and conclusions regarding
the trade-offs between the costs and effectiveness of the most promising control and
abatement strategies.
Disclosure Statement
This work was carried out by the Environmental Resources Engineering Department of
Humboldt State University through the Humboldt State University Foundation for the
California State Water Resources Control Board under Contract No. 7-703-150-0
beginning 10 December 1987. The total project budget was $80,000. Dr. Charles E.
Chamberlin was the project director and principal investigator. Drs. Ronald Chaney, Brad
Finney, Peter Lehman, Mac McKee, and Robert Willis were co-pnncioal invesng:tors.
2 .
I ”
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United S taxes Geological Survey has drilled coxes in Clear Lake sediment to depths up to
112 meters (350 feet) enurely within recent sediment Pollen data and ash bed correlations
from Clear Lake cores show a paleodlimauc record of approximately 130.000 years Sims
et al., 1981).
Sulphur Bank Mine
White and Roberson (1962) classify Sulphur Bank as the most productive mineral
deposit in the world that is clearly related to hoc springs. The ore is late Quaternarv in origin
and is localized in rocks immediately below the water table as it existed prior to mining.
The hydrothermal alteration and mineralogy of the veins have been conuvlled largely by the
water table.
At the time of its discovery by Veatch in 1856, native sulphur, without cinnabar, was
abundant near the surface; but, as the water table was approached, sulfur decreased, and
cinnabar became abundant The principal ore bodies were ax and below the water table and
consisted of cinnabar, maxcasite, pyrice, dolomite, calcite, quarta. a zeolite mineral, and all
minerals of the original rocks. In the process of removing the ore first by shaft mining and
later by open pit mining, overburden and waste rock piles and tailings piles were built up
within the anne site. For the purposes of the current work, the overburden and waste rock
piles that form the bluffs along the shoreline of the Oaks Ann of Clear Lake are the most
significant
The mineralization produced by the hot springs is quite recent (late Quaxernarv and is
still continuing (Sims and White, 1981). The springs in the vicinity of the mine yield gases
rich in C02, CH4, and H 2 S, in con ast to springs at other sites in the lake. Ac all sites.
mercury levels in the waxer and gases associated with the springs has been approximately 1
to 3 ppb (White et aL, 1970). The principal ore bodies at the Sulphur Bank Mine resulted
from the reaction of mercury and H 2 S to form the insoluble precipitate HgS, or cinnabar at
the interface formed by the groundwater table. The spring flowrate has been estimated
variously from 0.15 m 3 /min to 1.1 m 3 lmin. It currently enters the deep pond (Herman
Lake) filling the mine pit.
Although these deposits originally am acted commercial attention because of na ve
sulfur deposits (Ca. 1865), the Sulphur Bank mercury mine became a very producn’ e
mercury mine, active from 1873-97, 1899-1902, 1915-18, 1927-47, and most recently
from 1955-57.
White and Roberson (1962) cite unpublished data to estimate that the mine eided
129,418 flasks of mercury from 1873 through 1957. Each flask contained about 75 lbs of
mercury (specifically, 76.5 lbs from 1873 through 1903 and 75 lbs from 1904 on ara).
Therefore, the total commercial yield of mercury from the Sulphur Bank Mine as 3400 to
4500 MT. Taking into account mining and furnace losses and mercury left in the gi ’ound..
White and Roberson (1962) estimate that the original mercury content of the site i no
more than 7000 MT. Combining these limits, 4400 to 7000 MT of mercury were removed
from the site. According to Avenul (1947), mining activity at Sulphur Bank Mine r een
1865 and 1945 resulted in the removal, processing, and subsequent disposal of over
1,250,000 tons of material.
The mine is currently inactive. The site contains approximately 120 acres of t.1i n is,
overburden and dumps and 23 acres covered by a pond (up to 150 feet deep) 1tlhin ‘ e
abandoned mine pit, Neither the tailings nor dumps axe vegetated and are theretc’re ur’ject
F”
4
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to severe erosion. Along 1240 feet of shoreline, mine dumps are in direct contact with the
lake and are highly susceptible to shoreline erosion. Along an additional 820 ft. other mine
waste is in contact with water but less susceptible to erosion. See Figure LI-i.
Several geological maps of the mine site have been prepared: Becker(1888),
Ross(1940), Everhardt(1946), and Columbia Geoscience(1988). Figure 11-2 is based on
the most recent of these maps and distinguishes three categories of mine wastes: RMw -
overburden and waste rock, RMt - tailings, and RMu - undifferentiated excavated material
Water Quality Setting
Clear Lake consists of an approximately circular main basin or upper arm (UA) with
two narrow arms, the Lower Arm (LA) and the Oaks Arm (OA). See figures 11-3 and 11-4.
Inflows to the lake come primarily from Rodman Slough (Scotis Creek, Middle Creek),
Adobe Creek, and Kelsey Creek all of which enter the Upper Arm. A small (ca. 13 rm 2 or
34 km 2 drainage area) seasonal steam , Schindler Creek, feeds into the Oaks Arm. Outflow
exits from the Lower Arm via Cache Creek which is a thbutaiy of the Sacramento-San
Joachim system. Table 11-1 summarizes hydrologic data for these sites (USGS, 1984;
USGS, 1971).
Located along the north edge of the Clear Lake volcanic field, the lake is ax a current
elevation of 400 rn in a valley of the Northern Coastal Range, bounded by the Russian
River basin on the west. Its drainage area is about 5228 mi 2 or 1370 km 2 (Sims et al.,
1981). Lake morphological properties are summarized in Table 11-2.
The lake phytoplankton and producuvity have been studied by Goldman and others
(Goldman and Wetzel, 1963; Home and Goldmari,1972; Home et aL, 1971; Sandusky
and Home, 1978). The lake is classed as eun’ophic to highly eunophic but is thermally
snanfied for only short periods in the summer ranging from only a few hours to a week.
Water temperanne ranges from 6-27 C. Precipitation is concentiated from September
through April (valley - 56cm to hills - 165 cm). Both during winter storms ana aur ng e
summer. substantial wave action is observed. The sediment remains anoxic from Jw :o
November and the water near the sediments also has very low dissolved oxygen (DO)
levels. The water is quite turbid throughout most of the year.
Blooms of both blue-greens and dinofiagellates have been observed in the lake
(Sandusky and Home, 1978; Home and Goldman, 1971). Other dominant phytoplankton
species observed include Scenedesmus spp., Cryptomonas spp., and Cyclotella spp. In
some cases, the blooms have been, at least initially, concenuated in the Oaks Arm and/or
Lower Arm.
The lake is ranked as one of California’s most productive sport fisheries. It supports
over 300,0(X) angler-days per year of effort and yields 34.7 kgJha. Unfortunately, the
composition of the fishery catch has changed dramatically from the 1930’s to the present.
with marked declines in the largernouth bass populations (Week. 1982). The changes in the
composition of the catch and the decline in the largemouth bass fishery are both aimbuted
to loss of littoral (e.g., marshland) habitat.
In addition, Clear Lake has also had the distinction of being the only lake in California
to support a commercial fishery. About 250,000 lbs of Carp and 350,000 lbs of Blackfish
were commercially removed each year during the early 1970’s (DWR, 1975).
5
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Table IT-i
Streamfiow Properties
Drainage
USGS Area Ave Flow Mm Daily Period of
STN No. (mi2l (CFS (CFSI (*) Record
Adobe Cr. 11448500 6.36 11.8 0.00 (120) 1956-68
Highland Cr. 11448900 11.9 18.6 0.00 (30) 1964-68
Highland Cr. 11449000 12.7 20.1 0.00 (60) 1956-62
ScottsCr. 11449100 52.3 70.5 0.00(120) 1961-68
Kelsey Cr. 11449500 36.6 71.5 0.7 1947-68
Cache Cr. 11450500 528 500.8 0.0 (0) 1902-15
Cache Cr. 11451000 528 318.2 0.3 1946-68
Indicates the approximate number of days per year at 0.0 CFS.
Table 11.2
Clear Lake Morphology (after Home and Goldman, 1972)
Surface Mean Max Max
Area Depth Depth Fetch Volume
(mi2 l (hal (ml (ml (krnl (l0’ 6 m
UpperArm 49.0 12,700 7.1 12.2 16.4 904
Lower Arm 14.4 3,720 10.3 18.4 13.4 384
OaksArm 4.8 1,250 11.1 18.4 8.5 138
Total 68.2 17.670 8.1 18.4
Chemical analyses (Goldman and Werzel. 1963; DWR, 1975) show that the waters are
“hard’ with substannal levels of sulfate (see Table 11-3).
The lake lies in a fault-bounded valley and contains a long sediment accumulanon
history. Analysis of pollen patterns , C14 dating, and ash-bed correlations for long cores
removed from the UA indicate that the lake has existed for at least 130,000 years (SLrns et
aL, 1981). Cores taken from the Oaks Arm provide a sediment record covering about
44.000 years. Hot springs, some subaqueous, feed into the lake. carrying high levels of
CO 2 ana CH4.
Mercury levels in sediment cores indicate that there have been periodic episodes of high
mercury levels in the lake (Sims and White. 1981). Peaks are notable at 6 core depths vblth
ages estimated from C14 dates and ash-bed correlanons as summarized in Table 11-4.
4 -
10
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TABLE 11-3
Clear Lake Water Chemistry (Upper Arm)
Anions Concenuinon Cadons Concentration
(mg,I) (rn /1) (mg/i) (meajl)
HCO3 - 136 2.2 Mg ++ 17 1.4
S04-- 8 0.2 Ca+-s- 17 0.9
C- 7 0.2 Na+ 7 0.3
1 0.03
Total Anions 2.6 Total Cations 2.6
7.5 < pH <9
Table 11-4
Paleo-History of Mercury Contamination in Oaks Arm Sediments
(after Shns and White, 1981)
Peak Age Mercury Content
( Years Before Present) ( ppm )
3600 35
74.00 65
9500 12
18000 20
23300 5
34000 10
(local background) 0.4
High levels of mercury have been observed in the lake sediments and in fish and bird
populations. Typical values observed on the mine site range from 10 to 1000 ppm (dry
weight); in the surface sediments of the Oaks Arm mercury levels are generally about 10 to
100 ppm (dry weight). Sediment levels of mercury in the Upper Arm and Lower Arm are
much lower, suggesting localization of the mine conwibutions to the Oaks Arm. The
following chapter discusses these levels in greater detail.
In the fish and bird populations, mercury concentrations of 0.1 to 10 ppm (fresh
weight) am common. Tables 11-5 and 11-6 reproduce a summary of mercury levels in fish
and birds at Cle.ar l ik prepared by the CVRWQCB(1987). Mercury levels in the fish
species examined range 0.07 to 1.5 mg kg (fresh weight) while mercury Levels in the grebe
range from 0.4 to 9.8 mg/kg (fresh weight). The fish levels sometimes exceed the FDA
established limit of 1.0 ppm and often exceed the NAS level of 0.5 ppm established to
protect fish and predator species that consume fish.
11
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C 1 = mercury concentration in mbutary streamflow into the Oaks Arm
(kg/rn 3 )
Lab = flux from water column to sediment blanket (k /vr)
La = flux from water column to air (kg/yr)
= flow due to currents from the Oaks Arm into the Narrows (m 3 /vr)
= mercury concentration in Oaks Arm water column (kg/rn 3 )
La = flux from sediment blanket into sediments (kg/yr)
Estimates for some of these contributions can be taken directly from the hvdrolog c ‘)ajar.ce
for the Oaks Arm summarized in Table IV. 12 or from the analysis of mercury discharges
from the Sulphur Bank Mine site given in Chapter III. In this section, estimates will be
developed for the current mercury mass stored in the water column, the sediment blanket.
and the upper sediments and for the remaining contributions to the balance.
Mass Storage Levels
Three storage comparunents collectively make up the Oaks Arm and Narrows mercury
storage: I) storage in the water column (Sw), 2) storage in the sediment blanket Scb), and
3) storage in the upper sediments (S 5 ). The current mass of mercury stored in each of the
first two compartments can be estimated based on the observed mercury concentrarton i e.
mass/volume) and the compartment volume. The current mass in the upper sediments can
be estimated from observed mercury concentrations (i.e.. mass/mass dry weighti. ‘ . arer
content, bulk density. and compartment volume.
Essentially all of the mercury in the water column is expected to be associated
particulates which is consistent with the results of GiU(1987). In this project. water
samples were collected from the water column on four occasions at two locations at ti’ . e
depths each time. Sampling locations were determined by triangulation. Figure IV- 14
shows the sampling locations. Sample depths were distributed over the total ‘ . ater column
depth but were concentrated near the bottom, e.g.. if the water column depth “as 4() ft.
then samples might be collected at 3, 20, 30, 35, and 37 ft.
t .ich sample was analyzed ror mercury (i.e.. :otal recoveraole mercury r RH ’
Details ot the collection, sample handling, and analyses are given in Appencix A. .i
addition, half of the samples were filtered through 0.45 pm membrane filters to ret y
particulates and the mercury level in the filtrate was determined. This filtrable rracuon ‘ as
used to approximate the dissolved fraction. None of the filtered samples contained
measurable mercury levels but essentially all of the TR.Hg analyses contained 1c eL .ioo e
the detectable limit (i.e.. approximately 0.2 pg/I). Figure IV- 15 shows the mercur’.
profiles observed in the water column. Jo consistent pattern with depth or season is
evident. The average concentration based on all 40 samples was 1.0 u .gil with a stana rd
deviation (SD) of 2.1 pg/I. However, two of the observed concentrations were more itin
3 SD’s larger than the mean and were suspected of being contaminated ‘.‘.ith matenal rn
the sediment blanket. If these probably spurious data are censored, then the mein or the
remaining 38 observations drops to 0.5 pg/I with a SD of 0.3. The medians oi the tout
and the censored data sets were the same: 0.4 pg/I.
!3ased on a water level of 7.5 ft n the Rumnscv gagc. the ater ‘o unie of the Oaks .
0. 111 l0 ac-ft or 138 • l(P m 3 . The sediment blanket is assumed to be 1ppn .r rrn.izeL I
m thick. Since the surface area of the Oaks Arm is about 264 .ic or I I • lO n . U’e
volume of the sediment blanket is about II • lOb n ij. Therefore the ‘ . ater column ‘olurtt
/
79
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Sampling Methods
The following were the methods used for the collection of soil and water samples for
the study period of February 1988 thru March 1989.
Sample Types
Three types of sampling took place; subsurface, surface and shore sampling. Boats and
scuba diving teams were used for the subsurface collection of cores and suspended
sediment samples form the lake. Surface teams procured water column samples from the
lake by boat. Shore teams gathered soil samples and water samples from morutorrng weUs
and from the shores of both the lake and Herman Lake. Site location for the lake stations
was done by line of sight mangulanon from the boat or marked according land based
survey team mangulauon. Land stations were located according to surveys or by
cartographic marking.
Subsurface Transect Sampling
Using two boats the weighted ends of a twenty five meter uansect with makings at ten
meter increments and a float attached to the westward end, was released from a taught
surface position such that the tiansect was es.cennally suaight and oriented Eas JWest.
Additionally, a single boat method was applied by dropping the eastern end and running the
boat westerly releasing the float end while the boat was still moving and keeping the float
line taught. In either case, the float line was attached to the boat to act as an anchor line.
The suspended sediment samples were obtained prior to any core on a given ansect
for the purposes of minimal water column disturbance. All of the suspenaed sediment
samples were obtained utilizing a u ansect. such that one set was collected at each marking
for a total of three sets per nansecz. The cores were collected cm a basis Ut t O ‘e
a distance ot ten or twenty meters apart.
Subsurface Station Sampling
Using a single boat, an anchor line was lowered and the core taken near the anchor
Suspended Sediment Sampler
Discrete suspended sediment samples were obtained utilizing a polyvinyl chloride P\ C
pipe 110cm in length and a 6cm OD with circular openings drilled across the cenmii .i’
.ind through both sides at the selected heights of 100. 50. 0. 10 and 5 cm from the SL ’
grate bound to the bottom. In each opening a 60 ml all plastic syringe ith plunger
affi,ted in the PVC stand using waterproof tape.
While on the uanscct site, the leading diver would s 1 c iy lofler the grate into inc
edimeni-water interface .it an arms length in tront of them. Ensuring that the simrier
properly aligned vertically, they would then pull from the bottom plunger up t’illin t”c
syringes while making as little movement as possible. The tilled sampler was then rr - ’ .:
193
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Sulphur Bank Mercury Mine Mining Waste NPL Site Summary Report
Reference 2
Excerpts From Work Plan for the EPA Region IX In-house Remedial Investigation/
Feasibility Study, Sulphur Bank Mercury Mine Site: Interim Final;
EPA Region IX; April 1991
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WORKPLAN FOR THE
EPA REGION 9 IN-HOUSE
REMEDIAL INVESTIGATION/FEASIBILITY STUDY
(RI / FS)
SULPHUR BANK MERCURY MINE
SUPERFUND SITE
Clear Lake, California
INTERIM FINAL
April 1991
Prepared by:
Carolyn d’Alineida
John Lucey
Sharon Seidel
Stewart Simpson
Rich Freitas
Vicki Rosen
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TABLE OF CONTENTS
CHAPTER
1.0 Executive Summary
2.0 Site Background
Site Location, Description & Potential Contaminants
History of Mine Operations
Regulatory Status: Enforcement and Investigations
to Date
3.0 Site Physical Setting 3
Physiography
Climate
Regional Geology
Regional Hydrogeology
Site Geology
Site Hydrogeology
Surface Water
3.7.1 Herman Impoundment
3.7.2 Clear Lake
3.7.3 springs and Ponds
4.0 Site Contamination Characteristics 14
Study Area
Herman Impoundment Water and Sediments
Site Soils
Mine Waste Rock and Tailing Piles
Clear Lake Surface Water and Sediments
Ground Water
5.0 Conceptual Model of Site Contamination 19
- 5.1 Potential Contamination Sources and
Extent of Contamination
5.2 Contaminants of Concern
5.3 Contamination Migration Pathways
5.4 The Methylation Process
5.5 Toxic Effects
5.6 Uses of Mercury and Prevalence in the Environment
5.7 Potential Receptors
5.7.1 Surrounding Populations
5.7.2 Ecological Concerns
5.8 Conceptual Model
6.0 Preliminary Identification of Remedial Alternatives 31
6.1 Source Control Alternatives
6.2 Pollution Abatement Alternatives
2.1
2.2
2.3
PAGE
3.].
3.2
3.3
3.4
3.5
3.6
3.7
4.1
4.2
4.3
4.4
4.5
4.6
4 ’
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7.0 Data Managentent Requirements
33
7.1 Identification of Data Needs and Uses
7.2 Data Quality Objectives
8.0 Remedial Investigation 35
RI/FS Objectives
Project Planning and Management
Compilation and Review of Data
Development of ARARs
Development of CRP
Development of QAPjP
Development of HSP
Development of FSP
Field Investigation Activities
8.9.1 Herman Impoundment Operable Unit
a. Surface water Geochemistry
b. Groundwater Hydrology
8.9.2 Mine Waste Piles Operable Unit
a. Sampling of Soil, Mine Waste and Vegetation
b. Air Investigation
8.9.3 Lake Sediments Operable Unit
a. Water/Sediment Sampling
b. Ecological Assessment
c. Mercury Geochemical/Bioaccumulation Model
8.9.4 Cultural Resources Survey
8.9.5 Biological Assessment
Sample Analysis and Data Validation
Data Management and Interpretation
Remedial Investigation Report
9.0 Risk Assessment: 46
Human Health Evaluation
Ecological Assessment
10.0 Feasibility Study 47
Identification of Alternatives
Screening of Alternatives
Treatability Studies
Detailed Analysis of Alternatives
11.0 Remedial Investigation/Feasibility Study Reports 51
and Deliverables
8.1
8.2
8.3
8.4
8.5
8.6
8.7
8.8
8.9
8 . 10
8 . 11
8 . 12
10.1
10,2
10.3
10.4
I c ’
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r\1
APPENDIX
I. Tentative RI/FS Schedule
II. Compliance With Other Laws: Applicable, or Relevant and
Appropriate Requirements (ARARs)
A. Discussion
B. Initial Identification and Screening of ARARs
II. Remedial Investigation
A. Community Relations Plan (CRP)
B. Quality Assurance Project Plan (QAPjP)
C. Health and Safety Plan (HSP)
D. Field Sampling Plan (FSP)
III. Risk Assessment Workplan
A. Human Health Risk Assessment
B. Ecological Assessment
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SULPHUR BANK MERCURY MINE
RI/FS WORXPL N
1.0 Executive Summary
This workplan has been prepared for the In-House Remedial
Investigation and Feasibility Study (RI/PS) for the Sulphur Bank
Mercury Mine Superfund site located near Clear Lake, in Lake
County, California. The objectives of the RI/FS will be to
characterize the nature and extent of contamination at the site;
identify the contaminants of concern, and their potential migra-
tion and exposure pathways; evaluate the adverse effects of ac-
tual or threatened releases upon human and ecological receptors;
and evaluate the feasibility and cost-effectiveness of potential
remedial alternatives to aid in selecting a cleanup remedy.
The Sulphur Bank Mine is located on the eastern shore of the
Oaks Arm of Clear Lake, within a geotherinally precipitated ore
body of cinnabar (mercury sulfide) and native sulphur. During
past open pit mining activities, waste rock excavated from the
mine pit and ore processing wastes were directly disposed in
Clear Lake. Erosion from the mine continues to add to the mer-
cury contaminated sediments already present in the lake. Inor-
ganic mercury in the lake sediments is biologically converted to
methyl mercury, which bioaccumulates in the food chain. Tissue
samples collected from fish and some birds indicates that mercury
is concentrating in higher trophic level species. Many samples
collected from Clear Lake fish contain mercury levels in excess
of the U.S. Food and Drug Administration (FDA) guideline. Al-
though the State has issued a public health advisory limiting the
consumption of Clear Lake fish, the lake still supports an
economically important sport and commercial fishery.
The RI/PS will be conducted primarily in-house, using EPA
personnel and expertise to the maximum extent possible. Work
which cannot be readily carried out in-house will be assigned to
contractors. RI/FS will be conducted in a phased approach, and
wil]. focus on investigating and developing remedial alternatives
for three operable units: the mine pit, waste piles and con-
taminated soils, and contaminated lake sediments.
2.0 Site Background
1
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FIGURE 1
SITE LOCAT N MAP
SULFUR BANK MINE
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2.1 Site Location, Description, Potential Contaminants
The Sulphur Bank Mercury Mine (SB ) is located on the east-
ern shore of the Oaks Arm of Clear Lake, located in Lake County,
California (Figures 1 & 2). The surrounding area is largely
rural; the community of Clearlake Oaks (population 2,677) lies
approximately 1/2 mile across the lake to the north of the mine
site; the larger town of Clearlake (population 15,200) lies ap-
proximately 5 miles to the south. The Elem colony of Porno In-
dians is located immediately to the north of the site, a group of
residential homes are located just south of the mine, along Sul-
phur Bank Point.
Clear Lake is the oldest and largest fresh water body lying
entirely within California, and supports a highly productive com-
mercial and sport fishery. Clear Lake is classified as a highly
eutrophic lake, which supports large algal blooms during the sum-
mer months. Elevated mercury levels in Clear Lake were first
detected in 1970 by the California Department of Health Services
(DHS). Since that time, hundreds of samples from fish and
waterfowl tissues and water and sediment samples have been col-
lected near the SB site and elsewhere in Clear Lake. The
highest mercury levels found in Clear Lake were in the bottom
sediments of the Oaks Arm, near the Sulphur Bank Mine. Mercury
levels in Clear Lake fish often exceed the U.S. Food and Drug Ad-
ministration (FDA) and National Academy of Sciences (NAS)
guidelines for human consumption. The highest mercury levels
tend to be found in fish caught in the Oaks Arm of the lake.
The Sulphur Bank Mine has been identified as the most significant
source of mercury contamination entering the Oaks Arm.
The Sulphur Bank Mine, inactive since 1957, was one of the
largest mercury producers in California and has been considered
one of the world’s most productive mineral deposits clearly re-
lated to hot springs (White & Roberson, 1962). The Sulphur Bank
Mine is situated at the intersection of several regional faults
and associated shear zones which serve as avenues for upward flow
of hot-mineralizing water and gas. Prior to mining, the ore body
consisted of cinnabar (mercury sulfide, HgS) geothermally
precipitated along fault lines, in rocks immediately below the
water table. As the gasses produced by the springs rose above
the water table the mercury content of the ore decreased, and
elemental sulphur was deposited just below and at the ground sur-
face.
The mine site consists of approximately 120 acres of tail-
ings and waste rock and an unlined pit (Herman Impoundment) which
is filled with acidic water (pH 3) to a depth of up to 90 feet.
The mine tailings and waste rock were disposed in the Oaks Arm of
2
SW
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WINDFLOWER POINT WATER
WATER INTAKE
$ulpiu’ Søk P4.it
R.StI.wi ki FIISHWATE WE
IsInd
‘S
FIGURE 2
. & a .. .
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the Lake along 1,320 feet of shoreline. The Herman Impoundment
covers approximately 23 acres and is located 750 feet upgradient
from the lake. (Figure 3)
2.2 History of Mine Operations
The Sulphur Bank ore deposit was first discovered in 1857 by
Dr. John Veatch of the California Borax Company. California -
Borax Company filed a mining claim on the ore deposit and began
removing the sulphur from surface pits in 1865. The sulphur ore
was hauled away in rail cars to a refinery where the ore was
heated to a liquid state to drive off impurities, then cooled and
shipped. Mining operations ceased in 1871 when market prices
dropped and increasing cinnabar contamination increased the
refining costs. Approximately 1,000 tons of sulphur were
produced during this period. -
In 1872 California Borax Company reopened the mine for the
production of mercury ore. The ore was mined from the Herman
Shaft which was sunk to the 950 foot elevation (approximately 450
foot depth). The ore was heated with a fluxing agent in a Knox
Osborne/Scott furnace to vaporize the mercury, which was drawn
of f, collected and cooled to a liquid state. Approximately 3200
tons of mercury were produced by California Borax by the time
their operations ceased in 1883.
Sulphur Bank Quicksilver Mining Company resumed mine opera-
tions in 1887, sinking two new shafts: the Diamond shaft sunk to
elevation 1140 feet, and the Babcock shaft to elevation 1210
feet. Approximately 400 tons of mercury were recovered by the
time operations ceased in 1897.
Empire Consolidated Mining Company assumed ownership in 1899
and operated until 1906. The three previous shafts caved in; Em-
pire Consolidated sank the Empire shaft to the 1110 foot level,
and the Parrot shaft to the 1230 foot level, producing about 20
tons of mercury. Underground mining operations ceased in 1905
due to extreme heat and gas.
In 1915 to 1918, Sulphur Bank Association of San Francisco
resumed mining operations using open pit mining techniques. They
replaced the old Knox-Osborne/Scott furnace with a new rotary
furnace. 80 tons of mercury were produced during a three year
period.
Bradley Mining Company began open pit mining at the site in
1927, under a lease from the G.T. Ruddock Estate. They also sunk
two new shafts, which caved by 1944. With the introdtction of
power shovels and blasting techniques, 1200 tons of mercury were
produced.
3
4
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1 \
“7
Sourcs: Ru be1dt Stats University — Abats ent and Control Study
FIGURE 3
SULPHUR BANK MERCURY MINE
SITE GEOLOGY
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In 1945, following the end of World War II, Bradley Mining
Company ceased operations, allowing the mine pit to fill with
rainwater and run—off, forming Herman Impoundment. Bradley Min-
ing Company eventually assumed ownership of the mine and ten
years later, in 1955, Bradley Mining Company drained the mine pit
and resumed open pit operations, producing 120 tons of mercury
during the final production period. Mine operations ceased in
1957, and the mine pit again filled with water, forming the ex-
isting Herman Impoundment.
An estimated 4400 to 7000 tons of mercury were removed from
the site, considering furnace losses and residual left behind in
tailings and waste rock. Over 1,250,000 tons of material were
estimated to have been removed, processed and disposed during
nearly a century of mining activity.
2.3 Regulatory Status: Regulatory Enforcement and Investigations
to Date
Until the final NPL listing in August 1990, the Central Val-
ley Regional Water Quality Control Board (RWQCB) was the lead
regulatory agency at SBMN. Bradley Mining Company (BNC), the
current property owner, which conducted open pit mining ac-
tivities at the site during the last two productive periods
(1922-1944 and 1955—1957) is the only surviving potentially
responsible party identified to date.
Hundreds of fish tissue samples were collected by the
California Department of Fish and Game (DFG) during the late 70’s
and early 80’s which were found to contain elevated mercury
levels in edible tissue. Growing public and regulatory concern
led to the formation of the Clear Lake Mercury Task Force in
1983, which consisted of representatives from the California
Department of Health Services (DHS), RWQCB, DFG, Elem Indian
Reservation and several other county and local concerns. DHS
conducted toxicological studies concerning the elevated mercury
levels in Clear Lake fish, summarized in two reports: Methvl
Mercury in Clear Lake Fish: Guidelines for Fish Consumption (May
1986) and Methyl Mercury in Northern Coastal Mountain Lakes:
Guidelines for Snort Fish Consumption for Clear Lake (April
1987). In Nay 1986, DHS issued public health advisories recom-
mending restrictions on consumption of Clear Lake fish, which
have been incorporated in the California Sport Fishery Regula-
tions for each subsequent year.
Under the supervision of the RWQCB, Bradley Mining Company’s
consultant, Columbia Geoscience, has conducted several studies of
the SB site. In 1985, they completed a preliminary site as-
sessment. Under the Toxic Pits Cleanup Act (TPCA), BMC was re-
4
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quired to conduct a study of the contaminants in Herman Impound-
merit, which was completed in 1987. In December 1989, DM8 deter-
mined that the bottom sediments of the Herman Impoundment might
not be considered a hazardous waste under state law, as long as
they remain in place. However, if removed, the sediments would
be classified as a State—regulated hazardous waste. DHS indi-
cated that the erosional sediments from the mine tailings might
also be classified as a hazardous waste under state law, but more
information would be required to be certain.
Columbia Geoscience completed Phase I of the Hvdro eolo jca].
Assessment Report (MAR) in late 1988, addressing the on—site
ground water contamination. As a part of this study, several
on—site groundwater wells were installed, water samples were col-
lected, and field tests were conducted to determine aquifer
characteristics. The MAR study includes an on—going groundwater
monitoring program; Columbia Geoscience submitted the Phase II
and Phase X XI reports in 1989 and 1990.
Additionally, under a contract with the RWQCB, Humboldt
State University completed the Abatement and Control Study: Sul-
phur Bank Mine and Clear Lake in January 1990. The study iden-
tified the SB as the primary source of mercury contamination of
Clear Lake and proposed methods to control further mercury inputs
into the lake. Several abatement strategies were proposed to
control both the erosion of waste piles and to address the con-
taminated mine sediments already present in Clear Lake.
Following the completion of the Abatement and Control Study,
the RWQCB issued Waste Discharge Requirements (WDRs) to Bradley
Mining Company in February 1990 to address the erosion from the
mine site. The WDRs do not address the problem of the con-
taminated lake sediments. Under the WDRs, Bradley Mining Company
will be implementing erosion control measures over a 5 year
period. EPA will review and comment on Bradley Mining Company’s
submittals to the RWQCB, and oversee the work to be performed un-
der the WDRs. EPA’s Remedial Investigation and Feasibility Study
will be to characterize the potential threats posed by the SB)N
site- upon human health and the environment, arid to examine the
need for further remedial action.
3.0 Site Physical Setting
The Sulphur Bank Mine is located on the eastern shore of the
Oaks Arm of Clear Lake, approximately 1.5 miles south of the com-
munity of Clearlake Oaks in Lake County, California. The mine is
associated with naturally occurring geothermal hot springs which
have deposited various minerals at the site for thousands of
5
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Source: Humboldt State Univer.ity — Abatement and Control Study
FIGURE 4
MA3OR SECTIONS 0? CLEAR LAKE
Upper Basin
Oaks
LW I
0
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years. The following sections present a summary of what is known
about the site physical setting and the relationships between the
lake, the geothermal hot springs, and the mine site.
3.1 Physiography
The Sulphur Bank Mine property occupies approximately 2Q3
acres of land adjacent to the shore Clear Lake. The lake is
naturally occurring and lies in a valley formed by a complex
structural depression surrounded by mountains. Clear Lake is at
a current elevation of about 1320 feet above mean sea level (MSL)
and the surrounding mountains vary in elevation from 2000 to 4600
feet above MSL. The lake is 18 miles long, covers an area of
about 68 square miles, and is the largest freshwater lake en-
tirely within California. Clear Lake consists of an ap-
proximately circular northern main basin called the Upper Arm
with two southern narrow arms, the Lower Arm and the Oaks Arm
(Figure 4).
Communities surrounding the Sulphur. Bank Nine include Clear-
lake Oaks, residential homes located along Sulphur Bank Point,
and the Elein colony of the Poino Indians adjacent to the Sulphur
Bank Mine. Many recreational resorts and communities are located
on the shores of Clear Lake. Lake water is used for recreational
water sports, fishing, domestic purposes, and agricultural ir-
rigation. Important economic activities in the Clear Lake area
include cattle and sheep ranching, fruit orchards, recreational
resorts, forestry harvesting, and mining. Clear Lake is ranked as
one of California’s most productive sports fisheries and is the
only lake in California to support a commercial fishery.
3.2 Climate
The climate and vegetation of the Clear Lake area is typical
of Mediterranean climates. Moderate to heavy annual precipita-
tion can locally exceed 100 inches in the mountains and can be as
low as 20 inches in the Clear Lake basin. The mean annual
precipitation at the Sulphur Bank Mine is estimated to be 24
inches, with 80% of the rain falling between the months of Novem-
ber and March. Snow is common in the mountains above the 3,000
foot elevation. The mean annual lake evaporation is estimated to
be 48 inches. Mean monthly precipitation usually exceeds mean
monthly evaporation from November through February. Mean annual
temperatures for the Clear Lake area are about 60 degrees Fah-
renheit, with summer temperatures ranging above 100 degrees Fah-
renheit and winter temperatures below freezing.
6
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Vegetation patterns are affected by climate, elevation, and
soil type. Grassland, scrub oak, stands of cypress, manzanita,
and other chapparra].-type plants are distributed between the
lowlands and moderately high ridges. Evergreen conifers and some
deciduous plants, such as dogwood, are most common in the higher
elevations and often are specific to soils developed on certain
rock types, such as serpentine and rhyolite. Prevailing winds
are from a northwesterly direction. Air pollution is not a com-
mon problem at the site.
3.3 Regional Geology
The Clear Lake Area is located in the northern portion of
the Coast Range geomorphic province. Clear Lake is approximately
60 miles east of the San Andreas Fault at the margin of the
Pacific and North American Plates. The Coast Range is
predominated by north west-trending faults and shear zones re-
lated to right—lateral stress of the San Andreas Fault system.
Clear Lake is generally fault bounded and situated in a subsiding
structurally controlled depression. The structure in the Clear
Lake area is interpreted as a local development of the overall
structural pattern of the San Andreas Fault system, overprinted
by local deformations related to active volcanism. The subsiding
Clear Lake basin is thought to be an extension of a graben struc-
ture related to movements along the San Andreas Fault system.
The late Cenozoic history of Clear Lake is characterized by
faulting and volcanic activity.
Bedrock in the Clear Lake basin consists of the structurally
broken and complex group of rocks known as the Franciscan Forina—
tion. These rocks were formed approximately 65 million years ago
during the Cretaceous time period when the sea floor in the
Pacific Ocean was subducted beneath the North American continen-
tal plate. Sediment and rock scraped from the top of the descen-
ding Pacific plate, accumulated along the margin of the upper
North American plate, and formed the Franciscan Formation. The
Geysers-Clear Lake area has many occurrences of geothermal ac-
tivity -believed to be related to a shallow magma source defined
by geophysical evidence. The shallow magma chamber in this area
is also thought to be related to the subduction of the Pacific
plate beneath the North American Plate. The shallow magma cham-
ber is located within and below the Franciscan Formation which
acts as a cap rock to contain the magma. Geothermal activity is
evidenced in the surface geology where the Franciscan Formation
is thin or fractured and the magma chamber protrudes near the
surface. Commercial geothermal power plants are currently
operating near Cobb Mountain and the Geysers steam field located
about 15 miles southwest of Clear Lake.
7
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r .
*s 30 my.
d .
L
s_ c s
Source: XcLaughlin, USGS Professional. Paper 1141
FIGURE 5
MAJOR CRUSTAL FEATURES OF NORTHERN
AND THEIR RELATION TO EMPLACD ENT
BENEATH THE GYESERS-CLEAR LAKE
(1981)
CALIFORNIA
OF MAGMA
EA
*4
—-- mid
— w. c mip i
— mid —
&UI1 W —
T rm bI—
— w —
— _ 1 ___ J __
a
*1
-------
surface. Commercial geothermal power plants are currently
operating near Cobb Mountain and the Geysers steam field located
about 15 miles southwest of Clear Lake.
3.4 Regional Hydrogeology
There is relatively little background information available
on the regional hydrogeology of the Clear Lake area and the site
hydrogeo].ogy has not been fully characterized. The regional
ground water flow system primarily consists of relatively shallow
ground water aquifers which flow down from the surrounding moun-
tains into Clear Lake. It is believed that there is little
ground water seepage lost from Clear Lake because the entire lake
area is underlain by the impermeable, non-water bearing, Francis-
can Formation. The regional ground water flow direction in the
vicinity of the site is believed to be towards the North from the
steep mountains towards Clear Lake.
The U.S. Geological Survey has mapped numerous hot springs
throughout the Clear Lake area; many of them discharge directly
into the lake. (See Figure 6)
3.5 Site Geology
The geology of the Sulphur Bank Mine has been well docu-
mented in published literature. In general, the Herman Impound-
ment area is the center of a pipeline zone of hydrothermal al-
teration where three faults and shear zones intersect. Geother-
mal fluids moving upward along the faults altered the existing
rock units and deposited various minerals. The original ap-
pearance of the deposit was described by Veatch who discovered it
in 1856. The “hill of white powder” consisted of altered lava
impregnated with abundant native sulphur. Hot vapors and sul-
furous fumes escaped from cracks and fissures, and small springs
rich in boric acid emerged from the south base of the hill.
Prior to the first mining activity in 1856, the Sulphur Bank
area consisted of hot springs and gas vents surrounded by thick
deposits of native sulphur in a nearly pure form. As mining ac-
tivities proceeded deeper and the water table was approached, the
sulphur decreased and cinnabar became abundant. The principal
ore bodies were at or below the water table and consisted of cin-
nabar, marcasite, pyrite, dolomite, calcite, quartz, metacin-
nabar, and stibnite.
There are four major rock types present at the site. The
oldest rocks are metamorphic sandstones and shales of the Fran-
ciscan Formation of late Mesozoic age. These are overlain uncon-
formably by lake sediments and landslide debris of late Pleis-
8
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Adapted froa USGS Map XF-271, Sins & Rymer 1976
Sulphur
Bank Mine
FIGURE 6
APPROXIMATE LOCATIONS 07 GASEOUS SPRINGS
AND ASSOCIATED FAULTS IN CLEAR LAKE
‘I
a
S
S
S
/
4,
4
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site are thin, usually less than 30 centimeters, acidic, and
generally derived by residual weathering of natural rock and mine
waste rock. The four major rock types are described below:
Franciscan Formation — In the Sulphur Bank area the Franciscan
Formation is composed of contorted beds of graywacke and black
shale with local chert-bearing zones. Evidence of low-grade
metamorphism is present throughout the formation. In the eastern
portion of the mine area and where the formation crops out at the
surface in the western part of the mine, kaolinite/halloysite and
hydrous sulfate alteration of the Franciscan rocks is observed.
These white zones of alteration are often associated with the
smell of sulphur-bearing gas and no vegetation is growing on
these rocks.
Lake Sediments arid Landslide Debris — This grouping of sediments
generally consists of two major units. The uppermost unit is a
poorly bedded conglomerate and breccia, with many lenses of
cross—bedded sandstone and other beds that are dominated by silt
and sand. The conglomerates and breccias consist of blocks of
sandstone and shale derived from the Franciscan Formation, in a
shaly or sandy matrix. The angularity of these fragments sug-
gests a landslide origin for these sediments. Underlying the
coarser sediments is a thick section of blue—gray lake sediments
consisting mainly of clay with minor silt and sand. Drilling
near the site encountered about 60 feet of blue—gray clay. The
entire grouping of lake sediments and landslide debris is as much
as 200 feet thick in the south-central portion of the mine area.
Augite Andesite Lava Flow - An augite andesite lava flow overlies
the lake sediments. It mantles the area of about one square mile
above lake level and averages close to 100 feet in thickness.
The fresh lava is dark gray with irregular vesicles that are com-
monly more abundant in the upper part. The upper bleached zone
is generally glaringly white without prominent megascopic struc-
ture. In places it is in sharp contact with the underlying
boulder zone, but elsewhere the contact is gradational through a
few feet. The bleached zone consists predominantly of opalized
aridesite, best explained as a product of attack by sulfuric acid,
and corresponding to the near surface zone of bleaching in the
older rocks.
Post Andesite Sediments — The Andesite flow is overlain by s nds
and gravels of possible lacustrine origin as much as 50 feet
above the lake level. Two small patches of coarse clastic sedi-
mnents as much as 75 feet above lake level were also described as
lacustririe deposits. The origin and age of these rocks is uncer-
tain and has been debated.
9
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GEOLOGIC MAP AND SECTION A - A’
SULPHUR BANK MERCURY MINE
LGtND
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FIGURE 7
1
*1
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The mineral deposit at the the Sulphur Bank Mine is situated
at the intersection of three sets of regional faults and shear
zones which serve as conduits for upward flow from depth of hot
mineralized water and gas. Three sets of faults intersect at the
mine: 1) The northwest trending fault associated with the ore
body arid soil mercury anomalies; 2) A set of two steeply dipping,
northwest trending faults exposed in the mine workings; and 3)
the fault or shear zone delineated by as east-west line of gas
leakage. The faulting and the associated discharge of mineral
bearing geothermal fluids which formed the ore deposit postdates
the augite andesite lava flow.
The hydrothermal alteration and mineralogy of the ore and
gangue are controlled to a major extent by the water table. .The
upper part of the augite andesite flow probably has always been
above the water table and is extensively leached by sulfuric acid
formed by oxidation of hydrogen sulfide in the hydrothermal
fluid. Waters deep in the system appear to be neutral, but near
the water table they become acidic because of mixing with super-
gene nonineteoric waters containing sulfuric acid. Native sulphur
was deposited at the surface down to the water table. The main
ore deposit was restricted to depths near or below the inferred
position of the water table prior to mining. Rich ore bodies
were found as veins and disseminated masses in the lower part of
the andesite and in the lake and landslide deposits immediately
below the contact. Some commercial grade ore was deposited in
the Franciscan Formation but in decreasing concentrations with
depth.
The original location of geothermal springs and gas vents on
the site have been altered or covered up by mining activities.
It is likely that mining operations have altered the hydrothermal
system which previously existed at the site.
3.6 Site Hydrogeology
The major aquifer at the site is located within the lake
sediments and landslide debris deposit of late Pleistocene age.
The occurrence of ground water at the site generally corresponds
with the contact between the lake sediments and landslide debris
deposit and the overlying augite andesite flow. The occurrence
of ground water in the augite andesite flow and the interconnec-
tion between the aquifer and Clear Lake is unknown. The shallow
aquifer is unconfiried to seiniconfined and is first encountered at
depths of less than 3. foot near the shore of Clear Lake to 80
feet below the ground surface further away from the lake. The
shallow aquifer includes fractured rock of low permeability and
lake sediments of moderate permeability consisting of silt, sand,
a gravel alluvial deposits with thin clay layers. Wells screened
in the aquifer generally have a low yield which may be attributed
10
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to a low hydraulic conductivity and because the aquifer averages
only 75 to 100 feet in thickness. The permeability of specific
layers in the alluvial deposits is highly variable and the extent
to which individual layers are interconnected is unknown. it is
also likely that ground water exists within the waste rock stock
piles. The unsaturated zone at the site has not been charac-
terized. Also, the elevation of the ground water at the site has
been altered by mining activity and the existence of Herman Im-
poundinent.
The presence of Herman Impoundment clearly alters the direc-
tion of regional ground water flow and most likely creates a
ground water mound anomaly. Previous investigations have shown
that ground water flows from the higher elevation Herman Impound-
ment to the lower elevation Clear Lake. This flow direction is
confirmed by ground water surface elevations and pH gradients,
measured in three monitoring wells between Herman Impoundment and
Clear Lake. Other monitoring wells have been drilled at the site
but their present condition and locations are unknown. The
ground water flow characteristics on the north, south, and east
sides of Herman Impoundment are unknown.
Local geothermal waters flow upward from depth along fault
zones and are responsible for the formation of the Sulphur Bank
Mine deposit. The hot geothermal waters have a unique metamor-
phic origin and generally follow a fault zone located at the bot-
tom of Herman Impoundment, where previous mining activities and
mineral deposits were concentrated. The shallow water table
caused problems during early mining operations and has been al-
tered by the formation of Herman Impoundment. The temperature
and water chemistry of the shallow aquifer varies considerably
over the site. Water temperatures as high as 400 degrees
Farenheight have been measured at the site during previous
geothermal investigations.
3.7 Surface Water
- The two major surface water features related to the site are
Herman Impoundment and the Oaks Arm of Clear Lake. Some small
seasonal ponds and. springs are located in and around the mine
site. Surface water drainage from the site is to the Herman Im-
poundment and the Oaks Arm of Clear Lake. The majority of sur-
face drainage at the mine site drains into Herman Impoundment.
The water level in Herman Impoundment is several feet higher than
the level in Clear Lake. Potential overflow from Herman Impound-
ment would drain to Clear Lake. An earthen dam was constructed
on the west end of Herman Impoundment to control drainage into
Clear Lake. Three small drainage areas and the surfaces of
1].
-------
steeply sloped tailings piles at the lake shore drain directly
into Clear Lake. Parts of these tailings piles extend into the
lake and are exposed to erosion from wave action.
3.7.1 Herman Impoundment
Herman Impoundment is an unlined man—made excavation which
cuts through all four geologic rock units at the site including
the Franciscan Formation. Herman Impoundment is a highly unique
acidic water body containing elevated trace metals and standard
mineral constituents. The unique geochemical character of the
sediment and waters of Herman Impoundment is the result of a com-
bination of diverse sources. These sources include discharge of
natural geothermal fluids and gases, erosion of sediment from
waste rock and tailings, discharge of meteoric waters in contact
with waste rock and tailings, and chemical reactions with the im-
poundment water and the pit wall—rock. An analysis of the gasses
issuing from a vent near the north shore of the pit reported
93.33% carbon dioxide, 46% methane and 0.13% (1300 ppm) hydrogen
sulfide. The water in the pit contains dilute sulfuric acid and
has a pH of approximately 3.0. The acid is derived from oxida-
tion of of geothermal hydrogen sulfide gas venting into the bot-
tom of the pit and mixing with impounded water.
The pit is approximately 90 feet deep and has a surface area
of about 23 acres. The pit volume is approximately 700 acre
feet. Herman Impoundment is located 750 feet east of Clear Lake.
The earthen dam was constructed in 1979 at the west end of the
pit to provide sufficient freeboard to withstand overflow from a
200 year flood event. Prior to construction of the dam, water
from Herman Impoundment would overflow into Clear Lake seasonally
and during large magnitude storm events.
Even though no perennial streams exist near Herman Impound-
ment, there is an area immediately surrounding the pit that con-
tributes surface water run—off during storm events. This area is
estimated to have a drainage area of approximately 88 acres, not
including the surface water area of the pit, which varies from 21
to 23 acres.
Herman Impoundment is regulated under the Toxic Pits Cleanup
Act (TPCA) due to hazardous levels of mercury found in the sedi-
ments. The Central Valley RWQCB maintains that the hazardous
materials found in Herman Impoundment, derived principally from
mining activities, represent culturally disturbed or altered sub-
stances, and are therefore subject to state hazardous waste
management laws.
3.7.2 Clear Lake
12
1 \
-------
I ’
Clear Lake is 18 miles long, and covers an area of about 68
square miles. Clear Lake consists of an approximately circular
northern main basin called the Upper Arm with two southern narrow
arms, the Lower Arm and the Oaks Arm (Figure 4). The average
depth of the Upper Arm is 7.]. meters, the Lower Arm is 10.3
meters, and the deepest part of the lake is the Oaks Arm with an
average depth of 11.]. meters. Previous exploration drilling in-
vestigations performed by the USGS have recorded over 350 feet of
accumulated sediments in the bottom of Clear Lake.
The Clear Lake drainage basin covers an approximate area of
528 square miles (Figure 8). The main tributaries into the lake
consist of seven creeks, all of which enter the northern Upper
Arm. The lake drains from the south at Cache Creek on the Lower
Arm. The level of lake water is controlled by a dam at Cache
Creek; the lake is at a current elevation of about 1320 above
MSL.
Clear Lake is classified as a highly eutrophic lake and sup-
ports seasonal algae blooms of both blue-greens and dinof].agel-
lates. Considerable nutrient concentrations, related principally
to run-off from the drainage basin, sustain high levels of algae
growth. Studies have also been performed which indicate that
waste water treatment facilities at Clear].ake Oaks and other com-
munities are adversely impacting lake water quality. The algae
blooms often appear to be concentrated in the Lower Arm and the
Oaks Arm of the lake which may be attributed to prevailing
northwesterly winds that blow the algae blooms to the south and
east ends of the lake. Seasonal water temperatures range between
6 and 27 degrees Celsius. The pH is of the lake water is basic
and ranges from 7.5 to 9.0. Thermal stratification exists only
weakly and intermittently for periods of up to a week during the
summer. Bottom sediments remain anoxic during the summer and the
fall. The shallow lake is generally turbid because surface and
bottom waters are rapidly mixed by wind induced circulation.
Three separate sub—basin drainage areas with a total surface
area of 14 acres drain from the mine site directly into Clear
Lake. Steeply sloped tailing stockpiles from mining operations
are located adjacent to the lake shoreline and extend into the
lake. The tailing piles are in contact with about 2060 feet of
shoreline, and run—off from these piles also drains into Clear
Lake. Large storms are capable of producing strong wave ac-
tivity on the lake which results in erosion at the base of the
waste piles.
3.7.3 Springs and Ponds
13
-------
Source: Humboldt Stats University, Abatement & Control Study 1990
FIGtYRE 8
CLEAR L XE WATERSHED
I .
II
5 TflilP5
• •.•••. • • •
Cm’. Cr
I ’
-------
Submerged springs have been mapped throughout the entire
Clear Lake region (Figure 6). Several small seasonal springs and
ponds are located in and around the mine site. The exact number
and location of all the springs and ponds is unknown but several
have been identified. IHydrogeologica] . Assessment ReDort (MAR).
Columbia Geoscience) . The Green Pond is located within the tail-
ings piles and is extremely acidic with a pH of 2.27. This pond
acts as a retention basin for run—off from a portion of the sur-
rounding steeply sloped drainage area.
The temperature of naturally occurring springs in the
vicinity of the site is variable, and associated with gas vent-
ing. The original mineral deposit at the mine was formed by
thermal springs flowing upward along faults. These springs are
reported to still be actively discharging into the bottom of Her-
man Impoundment. Thermal springs have previously been reported
at the mine site and near the lake shore but they have apparently
been disrupted by mining operations or covered by tailings. It
is likely that mining operations have altered the hydrothermal
system that previously existed at the site.
4.0 Site Contamination Characteristics
This initial evaluation of contamination at the site is
based on a preliminary review of existing data concerning the
site. Data limitations of the existing data will be identified
and further investigated in order to completely characterize site
contamination. This evaluation includes a description of the
study area and contaminants at the mine site and in Clear Lake.
4.1 Study Area
The SB!’ site and surrounding areas which may be affected by
site contamination are the primary focus of RI/FS activities dis-
cussed in this work plan. The SB!*! property occupies ap-
proximately 203 acres of land. The study area consists of Herman
Impoundment and the SBMX property, and surrounding areas which
include but are not limited to, drainage areas contributing sur-
face water run—off to the site, surface soils down—wind from mine
smelting operations, the Oaks Arm of Clear Lake, the Elem Indian
Colony located adjacent to the site, the community of Clearlake
Oaks and other nearby residential areas. During the course of
the investigation other areas may be discovered which need to be
included in the study.
4.2 Herman Impoundment Water and Sediments
14
-------
The major surface water feature located on the mine site is
Herman Impoundment. The contamination in the Herman Impoundment
has been characterized in the Herman Lake TPCA Assessment report,
completed by Columbia Geoscience in 1987, under contract with the
Bradley Mining Company in compliance with the requirements of the
California Toxic Pits Classification Act (TPCA). The purpose of
the study was to characterize the chemistry of the water and bot-
tom sediments of the mine pit to determine if it fell within the
State definition of a toxic site.
The field investigation was conducted in early November,
1987. Prior to sampling, a bathymetric survey of the mine pit
was conducted using a recording fathometer along several
straight-line transects. The bathymetric survey revealed a maxi-
mum bottom depth of 90 feet. Gas discharges were observed and
recorded in several locations within the impoundment. (Figures 9
— 13).
Surface water temperature, pH, specific conductivity, and
dissolved oxygen readings were taken from several near—shore
locations. Pit sediments, thermal springs and ground water
samples were collected within and adjacent to the Herman Impound-
ment and analyzed for metals and selected anions. The results
are tabulated in Tables 1 & 2.
The TPCA report concluded that the water and bottom sedi-
inents of Herman Impoundment were below the toxic limits for all
title 22 categories of the Toxic Pits Cleanup Act, except for
mercury, which ranged from 9 — 46 ppm and averaged 26.33 mg/kg.
(TPCA limit - 20 ppm). Bottom sediments were found to be up to
27 feet thick in some areas, have an estimated volume of
5,990,000 cubic feet, and contain an estimated 7.74 tons of mer-
cury. Columbia Geoscience noted that the mercury concentrations
observed in the pit sediments were much lower that the mercury
levels observed in sediment cores taken from the Oaks Arm of
Clear Lake, and elevated mercury levels occur naturally
throughout the region. The major source of mercury in the pit
sediments is likely associated with detrital accumulation from
site surface water run-off. Less significant contributions may
be attributed to pit wallrock—water reactions and precipitation
from geothermal fluids entering the bottom of the pit.
The water in Herman Impoundment is very acidic with a pH of
about 3.0. The source of impoundment water is mostly from in-
filtrating ground water and surface run—off. Pit water also con-
tains high concentrations of sulfate, sodium, chloride, boron,
and ammonia. Two filtered samples of pit water had 1.3 and 0.75
ugh of mercury which exceed the EPA No-Adverse—Response Level
(SNARL) of 0.144 ug/l and the EPA ambient Water Quality Standard
to freshwater aquatic life of 0.012 ug/l. The pit water also ex-
ceeds drinking water standards for cadmium and ambient water
15
-------
BATHYMETRy OF HERMAN LAKE, CALIFORNiA
Lax, W& Lisa.....
XZ M e1(.3.
i sis ,
wa,z,t ,i • .
s usiLtis I ,e,,. .
• ..
3* Ii$ia.I4 seats •.,t
1 ,21.1 Hus.kefl
•*e4?1. •lsi e ISSL
tft.u anus
S .$ list
$4.14 Net
*31
•.U list
.2 12.12 list
1*.*4 Sties)
2. 1 1
__Ift .o. S00
. his e1$La ttauuss
P h?
Siits S•st•s al duS Si Pelt
Source: Herman Lake TPCA Assessment,
a’-
ISISLI? .11111 SS P*iy
p sss ,.I S S.I..ss. S.. slsse.
0.it.S$
Columbia G.osciencs,
1987
i s a
LUI _ • —
uats* .s’m 1 . t
FIGZJR! 9
-------
DISCHAGE AREAS
Os. ass. WSI tM e
ISS V s•I Sft ’p Os.
ZE
o-= - -4
1t
Source: Herman Late TPCA Assessment, Columbia Geoscience,
GAS
Os tIs a P•si
3.987
FIGURZ 10
-------
FATHOMETER RECORDS
iN PREPARING
USED
HERMAN LAKE BATHYMETRY
Lake TPCA AZS Si . t, Co1u bj Geoscience,
FIGURE 13.
1987
3 4
10
a.
at
ii!
fO
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0 1
10
$0
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J
$0
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•0
Source: Eer an
I
I
‘I ’
-------
— .I e ’
IN FREPAR INC
HERMAN LAKE BATHYMETRY
Source: Herman Lake TPCA Assessment, Columbia Geoscience, 1987
13
2
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so
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s0
I .o
70
so
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10
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$0’
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so
70
FIGURE 12
-------
FATHOMETER RECORDS USED
IN PREPARING
HERMAN LAKE BATHYMETRy
Source: Herman Lake TPCA Assessment,
Co1u bia Geoscience, 1987
0
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quality goals to protect freshwater aquatic life for beryllium,
copper, nickel, and zinc. Boron and ammonium concentrations
exceed EPA estimated permissible ambient goals.
Columbia Geoscience concluded that the acidic conditions of
the Herman Intpouridinent were due to the large volume of hydrogen
sulfide (H 2 S) in naturally discharging geothermal fluids reacting
with oxygen, rather than due to oxidation of pyrite-bearing rock
(FeS 2 ), to form sulfuric acid (H 2 S0 4 ), as is typical of acid mine
drainage. The report also concluded that mercury ore continues
to form in the mine pit and is not leaching from the sediments
into the water. Columbia Geoscience sensed that the physical and
chemical conditions in Herman Impoundment act as a natural treat-
ment process, trapping the discharging geothermal fluids, and
restricting solubility and confining the mercury to the bottom of
the pit.
Columbia Geoscience estimated that up to 8 tons of mercury
may be present in bottom sediments of the Herman Impoundment, and
more than 2,600 tons of mercury may exist within the ore bodies
below the mine pit.
4.3 Site Soils
The majority of contaminated soils at the site are as-
sociated with surface weathering of the mine waste piles. Con-
tamination of the tailing piles and associated soils are dis-
cussed in the following section. Other soils at the site which
could be contaminated are surface soils downwind from the mine
smelting operations which were adversely impacted by airborne
contaminants. The actual location and extent of these con-
taminated soils is unknown and will be further investigated
during the RI. -
A soil mercury survey was previously conducted at the site
during geothermal exploration activities. Soil mercury anomalies
are often associated with geothermal resources and can be used as
an indicator during reconnaissance exploration. The mercury sur-
vey at the site imply that the mercury bearing shear zone extends
both northeast and southwest of the mine and is at least two
miles long. A study of wind currents at the site demonstrated
that the soil mercury anomaly is not the result of downwind fall
out from processing the mercury ore. Soil sampling at the site
will be performed in order to determine the extent of naturally
occurring mercury anomalies and establish background levels for
the site.
4.4 Mine Waste Rock and Tailing Piles
16
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• TAILINGS AND MINE DUMPS
CLEAR LAKE
SULPHUR BANK MiNE
Hg data in
*
v - s
0
4 J
0
U
.1
I
-------
Two different types of mine wastes are found at the SBMM
site, including the reddish tailings (wastes from ore processing)
and waste rock, or unprocessed overburden excavated during mining
operations, which are white in color. Based on volume estimates
of existing tailings and waste rock piles on site, there is a
minimum of 193,600 cubic yards of wastes on site. The mine tail-
ings and waste rock extend 1,320 feet in the north-south direc-
tion, in contact with 2,060 feet of shoreline, and extend some
3,000 feet eastward from from the lake.
Sampling conducted on-site indicate the mine waste piles
contain elevated levels of mercury and arsenic. Samples col—
lected by the RWQCB from all over the mine site during 1983—1984
contained concentrations of mercury ranging from 1 — 624 mg/kg,
with a mean concentration of about 60 mg/kg (Figure 14). Arsenic
concentrations in the waste rock and tailings have been reported
as high as 140 ppm, but have not been sufficiently characterized.
However, surface water drainage from the mine site has been found
to contain arsenic concentrations as high as six times the Maxi-
mum Contaminant Level (MCL) of 0.05 mg/i (RWQCB, 1984).
Subsequent sampling of mine tailings by HSU at various
locations indicate the waste piles are uniform with respect to
the distribution of mercury levels. Samples that contained fine
grained material (clay and silt) had higher mercury contents than
samples without fines, but using conventional statistical methods
it is not possible to distinguish one sample type from another
based on mercury levels. In other words, what “hot spots” do ex-
ist are as likely to occur in one area of the mine waste piles as
another.
4.5 Clear Lake Surface Water and Sediments
Elevated levels of mercury were first detected in Clear Lake
in 1970 by the California Department of Health Services. Since
that time hundreds of samples from fish and waterfowl tissue and
from sediment and water in the vicinity of SBI*1 and in Clear Lake
have been analyzed for mercury. These data indicate that the
highest concentrations of mercury are found in the Oaks Arm of
Clear Lake in the proximity of SB?* . Of the mercury already in
the Oaks Arm, the largest amount (about 100,000 kg) is in the up-
per sediments, while the sediment blanket and the water column
account for much smaller quantities of mercury (respectively 440
kg and 60 kg). The most significant outputs of mercury from the
Oaks Arm are losses into the sediments; this amounts to ap-
proximately 100 kg of mercury per year. Losses to the atmosphere
and flows out of the Oaks Arm each account for approximately 10
kg per year.
17
I’
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C Y r L!A! LA SURIAC!
Regional 3oar Study ssu1ts
2/29/ SM..3/1/84
Source: Regional Water Quality Control Board
IL ,-
, 1
-—aec, £tu4 y esuits
8/83
L csti
Rodman Si.
lower Lake
Rattl. snake
Is.•
Bulf u’ Bask
!‘line Tail.
Z St ady
Results
Locatioj !Sh
Upper Ar
Lower £x
Oaks Ar
3 1
4.4
33.4
oI
o:
14.4
430.
FIGURE 15
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Historically, mining practices have contributed mercury into
the lake during the periods of 1927—44 and 1955—57 and appear to
be the most likely source for the mercury stored in the upper
sediments of the Oaks Arm. Mercury inputs from mining sources
can be further subdivided into five major categories: 1) From
mine water and sludge pumped into the lake during open pit mining
operations; 2) Airborne inputs during ore smelting operations at
the mine; 3) Disposal of wastes during smelting operations; 4)
Erosion of detrital material from unstabilized waste piles and
local drainages; and 5) Ground water discharge from Herman Im-
poundment into Clear Lake. Natural inputs from active geothermal
systems have been documented in the vicinity of SBMN and
throughout the Clear Lake area. The mercury in the deeper por-
tions of lake sediments are associated with natural deposition
prior to mining operations at the site.
Mercury levels in the lake water are generally very low and
near or well below the analytical detection limit of 5 ugh.
Mercury concentrations from lake bottom sediments in the Oaks Arm
range between 11 mg/kg and 250 mg/kg (dry weight) with an average
of 80 mg/kg. This is well above the state action level for mer-
cury in sediments of 20 kg/mg. Bottom sediment samples in the
rest of Clear Lake range from non-detect to 12 mg/kg with an
average of 2 mg/kg (Figure 15). Short cores collected from lake
bottom sediments in the Oaks Arm in the vicinity of SBMM contain
high levels of mercury in the upper 50 to 60 cm of sediment,
which corresponds with the last 100 years of lake deposition,
during the period mining activity. Substantially lower amounts
of organic matter and soil moisture coincide with this mercury
peak, suggesting a changing lacustrine depositiorial environment
with higher shore-derived detrital influx. The presence of pes-
ticides from aerial spraying during the l950s and l960s in these
upper sediments provide further evidence of recent deposition.
Sediments below this mercury peak contain substantially lower
concentrations of mercury, until a depth of about 4 meters is
reached where a natural mercury peak occurs (depositional age es-
timated to be about 6000 years before present).
High arsenic levels have also been detected in the bottom
sediments of the Oaks Arm of Clear Lake. Concentrations from
twenty samples ranged from less than the detection limit at 5
mg/kg to 95.9 mg/kg arsenic with an average of 27.9 mg/kg.
4.6 Ground Water
Ground water contamination has been characterized by data
collected from wells on site and nearby. Three monitoring wells
are known to currently exist at the site. No domestic water•
wells in the vicinity of the site are known to have have detec-
table levels of mercury. Mercury levels in water, and specif i—
18
1
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-a
cally ground water, s dependent upon pH, Eh, chloride and su].-
fide levels, and temperature. Observed levels in filtered and
unfiltered samples from springs and wells near mercury deposits
in north—central California are reported to range from non—
detectable to 0.7 ugh. The “Sulphur Bank” well is reported to
have levels of 0.5 ugh, in a 1973 survey. The HAR reports mer-
cury levels at 0.2 ugh in the unused Bradley Mining Company well
BN3 located on site.
Humboldt State University (HSU) sampled three on site ground
water monitoring wells for the Abatement and Control Study com-
pleted under contract to the RWQCB. Mercury analysis of unfil-
tered samples from the monitoring wells ranged from about 7 to
130 ug/l of total recoverable mercury. Analysis of two filtered
samples from one single monitoring well were 0.4 and 0.6 ugh of
mercury and 60 and 15 ugh for the other two wells. However, HSU
considered the latter two results suspect due to improper filtra-
tion.
The magnitude of ground water transport of mercury from Her-
man Pit to Clear Lake is dependent on the elevation difference
between Herman Pit and Clear Lake, the hydraulic conductivity of
the aquifer, the thickness and area]. extent of the aquifer, and
the mercury level in the ground water transport. Since the water
level of Herman Lake is approximately 3 to 10 feet higher than
the level of Clear Lake it is likely that ground water flows from
Herman Pit to Clear Lake. The flow of ground water from Herman
Pit to Clear Lake is further supported by the hydraulic head and
pH gradient measured in the three on site monitoring wells. The
pH gradient went from 2.8 at Herman Lake to 4.1 in the well near
Clear Lake. Using computer modeling and assuming a flow rate of
20 gpm and 0.5 ug/l as the mercury level, the annual ground water
input of mercury is estimated to be 0.02 kg/yr. By this estima-
tion, the contribution of mercury in the ground water from Herman
Pit into Clear Lake is very low in comparison to other transport
mechanisms such as shoreline erosion.
No domestic, stock or public water supply wells are located
downgradient of the Sulphur Bank Mine. Mercury concentrations in
water from nearby wells were at or below detection limits at the
date and time of measurement.
5.0 Conceptual Model of Site Contamination
5.1 Potential Contamination Sources and Extent of Contamination
19
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Mercury inputs - into Clear Lake can be subdivided into two
sources: mining activities and natural sources. The Sulphur Bank
Mine is not the only mercury mine in the Clear Lake area. The
abandoned Bell Mine, and the nearby S-Bar-S quarry are both lo-
cated in the vicinity of Mount Konocti. Other mercury mines in
Clear Lake region include the Mirabel, Helen and Abbott Mines.
At the SB site, contaminant sources directly resulting
from mining activity include the mine tailings and waste rock
piles, which continue to erode into the lake, and the mercury
contaminated sediments resulting from direct disposal into the
lake. Acid water from the Herman Impoundment from groundwater or
surface water discharges may also leach metals into Clear Lake
and impact water quality. High concentrations of mercury have
been reported in the mine tailings and waste rock piles, ranging
from 1 to over 600 ppm mercury. Lake sediment samples collected
just off shore from the mine site have been found to contain as
high as 250 ppm mercury. Elsewhere in the lake, outside the
Oaks Arm, bottom sediments have thus far been found to contain
mercury levels ranging from non—detect to only as high as 12 ppm.
(Figures 14 & 15) The state action level for mercury in sedi-
inents is 20 ppm.
Natural mercury inputs from active hydrothermal sources have
also been documented within the immediate vicinity of SBMM. Hot
springs have been observed discharging into the Herman Impound-
ment and elsewhere on the mine site. Historical accounts indi-
cate that several large springs existed along the Clear Lake
shoreline, before the hydrothermal system was disrupted by mining
activity. The U.S. Geological Survey has mapped numerous springs
throughout the Clear Lake Area (Sims & Rymer, 1976). The con-
tribution of these natural springs to the methylation and bioac—
cumulation of mercury in Clear Lake fish must be investigated
prior to selecting a cleanup remedy for the contaminated lake
sediments.
5.2 Contaminants of Concern
To date, mercury, in both it’s inorganic and methylated
forms, and arsenic have been identified as the primary con—
taminarits of concern. Previous investigations have not suff i—
ciently characterized the extent and significance of arsenic con-
tamination. Other metals may also be present in the sediments,
tailings and waste rock, in concentrations which may effect water
quality, but data collections to date have not been sufficent to
identify other metals as contaminants of concern.
5.3 Contaminant Migration Pathways
20
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a) Shoreline Erosion: — - - -
Approximately 2060 feet of Oaks Arm shoreline is in direct
contact with mine wastes; of this, about 1240 feet of shorelIne
is in contact with very steep (up to 60 degrees), barren slopes
made up of tailings and waste rock. Samples collected by Hum-
boldt State University contained an average mercury level of 158
ppm. Two possible erosional processes for mercury transport from
the shoreline deposits into Clear Lake include sheetwash erosion
from the steep banks and slope failures due to undercutting of
the slope by wave action. The shoreline slopes have well
developed gully systems and talus cones, indicating sheetwash
erosion and mass wasting processes are in progress. Humboldt
State University (HSU) estimated the annual contribution of mer-
cury due to mass wasting processes at 132 kg/yr, based on field
measurements made using an array of erosion pins and measurements
of precipitation and soil properties. These measurements were
taken during dry years (1988-1989); consequently, the normal ero-
sion rates may be higher.
b) Fluvial Transport
In addition to shoreline erosion, drainage from the rest of
the mine site is likely to carry additional mercury laden sedi-
ment into the lake. The possibility of failure of the dams con-
taining the Herman Impoundment during heavy rains is of par—•
ticular concern, and is being addressed under the RWQCB order.
Water samples collected from on-site ephemeral streams by RWQCB
in 1989, contained mercury levels between 330 and 490 ppb. Based
on estimated annual discharge rates, Humboldt State University
estimated the average annual mercury discharge from fluvial
transport ranges from 1.24 to 18.6 kg Hg/yr.
C) Ground Water Transport
As the water level in Herman Impoundment is approximately 10
feet higher than in Clear Lake, ground water flows is likely to
be from the mine pit into the lake. The depth to the water table
is approximately 10 feet. Two wells were installed by Humboldt
State University between the Herman Impoundment and Clear Lake,
and head and pH gradients were measured confirming this assump-
tion. The pH gradient went from a pH of approximately 2.8 at
Herman Impoundment to 3.9 in the well closest to the mine pit, to
4.1 in the well nearest the shoreline, to 6.9 in the lake.
The aquifer between the Herman Impoundment and Clear Lake
consists of 3 layers. The upper layer consists of the waste rock
layer, which is underlain by a unit of quaternary sediments up to
35 feet thick, including silty lake sediments, landslide debris
and beach sediments. Quaternary andesite volcanics, of unknown
thickness, make up the bottom-most layer of the aquifer.
21
( J
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Columbia Geoscience estimated hydraulic conductivities for
these units through pump tests and litho].ogic interpretations.
The hydraulic conductivity of the waste rock unit was estimated
to range from 1.8 X 10 to 8.4 X 10 cmJsec. For the quater-
nary sediment 1aye , hydraulic c2nductivities were estimated to
range from 1 X lO ’ to 4.3 X 10° cm/sec, and for the andesite
volcanics, 3.4 — 3.6 X io6 cm/sec.
Mercury levels in groundwater are dependent upon pH, PE,
temperature and levels of chloride and sulfide. Samples col—
lected from on—site wells (Columbia Geoscience — 1988) had
reported mercury levels ranging from non-detectable Cc 0.2 ug/l)
to 0.2 ug/].. Unfiltered samples collected by HSU ranged from 7
to 130 ugh recoverable mercury. Filtered samples contained 0.4
and 0.6 ugh in one well and 60 and 15 ugh in the other two
wells. IjsTJ considered the latter two results suspect due to im-
proper filtration.
Based on modeling, HSU and Columbia Geoscience reported es-
timated ground water transport rates for mercury to be 0.0001 -
0.02 kg/year.
d) Air Transport
Previous investigations have not evaluated the air migra-
tion pathway. However, a mercury vapor survey was conducted on—
site by the RWQCB in 1988. The survey was conducted using a
Jerome Instruments mercury vapor analyzer. The results indicated
that vapor concentrations throughout the site were well below the
NIOSH recommended exposure limit (10 hour time weighted average,
TWA) of 0.05 mg/cubic meter. The highest levels found, (0.012
mg/cubic meter) were found inside structures in the old mill
processing area. Background concentrations were mostly between 0
and 0.002 mg/cubic meter, with occasional readings as high as
0.05 mg/cubic meter. Mercury vapor concentrations near the hot
springs were not higher than for other areas.
Prevailing winds blow in an easterly direction across the
mine site. The potential also exists for particulates to be
blown off—site. On windy days, hydrogen sulfide fumes can be
smelled as far away as the mine gate.
Both the on—site caretakers residence and several homes in
the adjacent Elem community were constructed on mine waste. To
date, indoor mercury concentrations in those homes have not been
measured.
5.4 The Methylation Process
22
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The recent discovery of elevated mercury levels in certain
aquatic species and subsequent findings that mercury tends to
bioaccumulate and concentrate in higher life forms, with poten-
tially serious toxic effects, spawned a surge of research into
the behavior of mercury in the environment. Research has shown
that while mercury in water is present predominantly in inorganic
form, methyl mercury is the form usually identified as being
present in contaminated aquatic organisms. Inorganic mercury is
biologically converted to it’s methylated form by microorganisms
present in the water and sediments.
Inorganic mercury may enter the natural waters as dissolved
mercury bound to suspended solids, as detrita]. cinnabar, or in
solution. Inorganic mercury may be present in elemental form
(Hg’ ’, metallic vapor) ionic form (Hg , formed by photochemical
ox dation in air or possibly by methylation, or more commonly,
Hg ) or as a compound (e.g.: HgS). Metallic mercury and mercury
compounds have low solubility in water (>1 ppm) and tend to sink
below the sediment/water interface and become immobilized. Ionic
mercury is more soluble, and may form organic species. In
general, the speciation of mercury in natural waters is dependent
on pH, redox potential, and availability of ligands or binding
groups. Under most conditions, dissolved mercury is mainly bound
to solids via surface layer adsorption to clays, hydrous oxides,
and organic debris so that at least 50%, and more likely 80—96%
of total mercury is transported along with suspended solids. The
movement of mercury between the water column and surface sediment
is rapid, reaching equilibrium within days, and is responsive to
short—term physical and chemical changes.
Inorganic mercury is converted to organic mercury in either
the form of monomethylmercury (e.g.: methylmercuric chloride) or
dimethylmercury. Dimethylmercury is the ultimate product, which
may rapidly volatilize in the water column. Monomethylmercury is
more stable and more likely to bioaccumulate. Methylation of
mercury appears to occur primarily in the upper 5 to 15 cm of
sediments under mildly to strongly reducing conditions. Methyla-
tion has been shown to occur in the water column as well as in
sedIments.
Levels of methyl mercury may fluctuate seasonally as the
lake switches from aerobic to anaerobic conditions. In addition
to dissolved oxygen content, other factors governing the methyla—
tion process include temperature, pE, pH, type and concentration
of bacteria present, and type and concentration of complexing or-
ganic and inorganic ligands and chelating agents (ie: reduced
sulphur, chlorides, hydroxides, and suspended solids).
23
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Mercuric ions also tend to chemically adsorb to humic mat-
ter, forming soluble complex ions. WM1e these complex ions may
not be readily available for methylation by bacteria, they may be
oxidized, or metabolized by benthic organisms, and thereby made
available to bioaccumulate.
It has been clearly shown that fish assimilate methyl mer-
cury directly from the water column through their gills, from the
upper layer of sediments, and may also produce methyl mercury
within their own intestines from mercuric precursors. Once in
the food chain, mercury may bioaccumulate at levels exceeding FDA
guidelines, particularly in the upper trophic level species.
The following mathematical model has been proposed and
verified for describing the methylation phenomenon (Bisogni &
Lawrence, 1975):
NSNR =
where:
NSNR = Net specific 2nonoxnethylmercury production rate
a = microbial growth rate
b = biochemical availability of inorganic mercury for
rnethylation -
n = reaction order (For mean aerobic systems, n = 0.28;
for mean anaerobic systems, n = 0.15)
As numerous factors may potentially effect the methylation
process, it may be possible to reduce the methy].ation rate in a
given natural system by the manipulation of one or more factors.
Several remedial strategies have been proposed to date, includ-
ing:
1) change the mercury binding characteristics of the sediment by
adding a strong complexing agent (such as sulfide ions) in suff i-
dent quantity to reduce the availability of mercuric ion for
methylat ion.
2) Eliminate or reduce organic input in the benthic zone to stop
or reduce biological activity.
3) Reduce the total inorganic mercury concentration by:
a) dredging, treatment and off-site disposal of mercury
contaminated sediments.
b) covering contaminated sediments with a cap of sand, clay
or gravel.
c) using a getter system (mesh network treated with a
24
I ’
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complexing agent, such as sulphur) to adsorb mercuric
ions and remove them from the water column.
In order to select the most appropriate remedial strategy
for a particular system, it is essential to understand which fac-
tors control inethylmercury production in the particular system of
concern.
5.5 Toxic Effects
A considerable amount of research has been conducted and
data published on the toxic effects of mercury poisoning, par-
ticularly since the widespread outbreak of mercury poisoning in
the fishing village of Minimata, Japan in 1953. For years, a
plastics plant had directly discharged methyl mercury into the
bay. Strange behavior and high death rates were first noted in
cats, then neurological disorders, birth defects, and some deaths
were reported in the human population. After intensive inves-
tigations, the cause of the epidemic was found to be mercury
poisoning from the consumption of local fish and shellfish. The
source of the mercury was eventually traced to the plastics
plant, where near—shore sediments were found to contain as high
as 2010 ppm mercury. (Sediments in the Oaks Arm of Clear Lake
range from 11 to 250 ppm mercury, with an average concentration
of 80 ppm.)
Another case of mercury poisoning was reported in the early
1970’s in Iraq, where homemade bread made from seed wheat that
had been treated with a mercurial fungicide poisoned over 6500
children and adults. Over 500 hospital deaths were reported;
many other deaths may have gone unreported. Patients experienced
numbness in their hands, feet and around the mouth (paresthesia),
loss of motor control (ataxia), slurred speech (disarthria), tun-
nel vision and hearing loss.
Symptoms of mercury poisoning include headaches, weakness,
forgetfulness, aggressiveness and personality changes in its
mildest form, and tingling skin, muscle numbness and slurred
speech, to convulsions, delirium, respiratory failure, kidney
failure, and death in its most severe forms. The milder symptoms
of mercury poisoning, (headache, fatigue, memory loss, lack of
concentration) are reversible; the physical effects, (blurred vi-
sion, hearing loss, impaired motor control, numbness) are irre-
versible.
Mercury has been found to be a teratogen in all animal
studies; there have also been reported cases of blindness, hear-
ing loss and mental and physical defects in human babies exposed
to mercury in the uterus. In most cases of fetal exposure, in-
fants appear normal until the age of six months, then begin to
25
.1 ,
, 1
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show signs of slowed reflexes, poor motor control, delayed speech
and cerebral palsy. Mercury kills brain cells and other nerve
cells, possibly due to its tendency to form covalent bonds with
sulfur, by deactivating sulfhydryl enzymes essential to cellular
metabolism. In pregnant women, mercury tends to cross the
placenta and concentrate in the fetus; breast milk may also con-
tain concentrated levels of mercury.
Mercury is toxic in both its organic and inorganic forms.
Inorganic mercury most frequently effects the kidneys first, and
may also damage the central nervous system with chronic exposure.
Organic mercury tends to be retained in the body, particularly in
the brain and the placenta. It attacks the central nervous sys-
tem and is the form of mercury most often responsible for birth
defects.
Methyl mercury is the organic form of primary concern at
SB 1. Inorganic mercury in lake sediments is converted biologi-
cally to methyl mercury, which enters the food chain and bioac-
cumulates and concentrates in higher trophic level species.
Studies have shown that 98% of methyl mercury in food is absorbed
by the tissues, whereas only 1% of inorganic mercury is absorbed.
At Clear Lake, high mercury levels in fish prompted the Califor-
nia Department of Health Services to issue a health advisory in
May 1986 against consumption of all Clear Lake fish for pregnant
women, nursing mothers, and children under age 6, and limiting
fish consumption for all others.
While fish consumption is a primary route of exposure, mer-
cury poisoning can also occur through inhalation of mercury dusts
or vapors and skin contact with methyl mercury or organic salts.
Although the U.S. Food and Drug Administration has issued an
action level of 1 ppm mercury in food, toxic effects are
generally not seen until a level of 10 ppm is reached. The ac-
ceptable Daily Intake (ADI) for an average 70 kg adult is 30 ug
methyl mercury per day. The World Health Organization (WHO) has
established 10 ng Hg/mi (0.010 ppm) as a “safe” blood level, al-
though the lowest blood level associated with adverse health .ef-
fects found to date is 200 ng Hg/mi (0.2 ppm), taking into ac-
count the most sensitive populations. Methyl mercury has a half
life of 70 days in most humans, however, in some individuals, it
may take up to 120 days to excrete half of the toxin. Mercury
levels can be measured in hair, blood and urine samples. While
hair and blood data tend to correlate well, urine mercury levels
cannot be used to calculate an exposure level, but can only be
used to provide evidence of recent mercury exposure.
5.6 Uses of Mercury and Prevalence in the Environment
26
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Mercury has anuinber of industrial uses, including the
manufacture of chlorine and caustic soda (chior—alkali industry)
and plastics manufacturing. it was formerly used as a slimicjde
in the paper manufacturing industry, and is still used in
agriculture as a fungicide treatment for seeds. Mercury has also
been used in paint, cosmetics, filters on sewage treatment
plants, thermometers and scientific instruments, dental prepara-
tions, amalgamation, and various mining extraction processes.
Coal burning power plants also produce mercury vapor; mercury
also occurs naturally in fossil fuels.
Although there are hundreds of potential uses for mercury,
only about 18% is recycled. Most of it eventually ends up in the
environment.
5.7 Potential Receptors
5.7.1 Surrounding Populations
The Elem community of Pomo Indians is located on the north
side of the SB site. The community consists of approximately
21 homes and a community center, half of them constructed on mine
tailings and waste rock. While the residents formerly relied
heavily on subsistence fishing, most of them no longer eat the
fish due to the health advisory. Residents still collect tules
along the shoreline and eat the raw bulbs. Children freguently
play on the mine site and eat wild blackberries that grow on mine
tailings. The community’s drinking water wells are abandoned;
water is now piped through the lake from Clear Lake Oaks. In ad-
dition to the Elem community, the caretaker’s residence is lo-
cated on the mine site and was constructed on mine tailings;
eight other homes are located just to the south of the mine. The
fish and wild game consumption habits and drinking water source
for these inhabitants is presently unknown.
The nearby communities of Clear Lake and Clear Lake Oaks,
population 15,000 and 2,700 respectively, may also be affected.
Residents may still be eating fish caught in the Oaks Arm of the
Lake, also, residents have reportedly used algae from the lake as
compost for vegetable gardens. Samples of algae collected by EPA
from the canals in Clearlake Oaks contained low levels of mer-
cury, below 0.16 ppm (wet weight). The drinking water supply
wells for Clear Lake Oaks are located near the Clear Lake
shoreline. The depth and screened intervals of the wells are
presently unknown, but these wells could conceivably be pumping
lake water.
4 27
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- I4any of the nearby residents and tourists who come to the
area swim in Clear Lake. As methyl mercury may also be absorbed
through the skin, swimming provides another possible exposure
route.
Beef cattle and sheep also graze near the mine site. hi1e
health advisories have been issued against consumption : iear
Lake fish, there are currently four commercial fishing ienses
issued for Clear Lake. Most of the fish are caught in ie Upper
Arm and only a few species are marketed commercially, including
Sacramento Blackfish, Carp, Clearlake Hitch and Goldfish (sold a
Silver Carp). These fish are sold to Asian markets in the - -
Area, Sacramento and Los Angeles.
5.7.2 Ecological Concerns
Clear Lake is host to a variety of terrestrial, aquatic and
benthic communities. The surrounding area includes freshwater
marshes and seasonal wetlands containing sedges, rushes and
grasses; riparian—woodlands dominated by hardwoods, pines, wi].-
lows and vines; and grassy chaparrals of shrubs and brush
species. These are home to deer, gray squirrels, raccoon, fox,
mink, jackrabbit, and many other small mammals, as well as
egrets, great blue heron, the rare yellow—billed cuckoo, owls,
and many other waterfowl and birds of prey. The U.S. Fish and
Wildlife Service reports that federally endangered species found
in Lake County include:
American Peregrine Falcon ( Falco peregrinus anatum )
Bald Eagle ( Haliaeelus leucoupha].us ) -
Northern Spotted Owl ( Strix occidentalis caurina )
Loch Lomond Coyote Thistle ( Ervn iuin constancei )
Other California rare, protected and endangered species and U.S.
Forest Service sensitive species found in Lake County include:
Black-shouldered Kite ( Elanus caeruleus )
Northern Goshawk ( Acci itier aentilis )
Golden Eagle ( Acuila chrvsaetos )
Prairie Falcon ( Falco inexicanus )
Blue Grouse ( Dendra apus obscurus )
Ringtail ( Bassariscus astutus )
Badger ( Taxidea taxus )
Although various wildlife species may prefer one particular
vegetative habitat type, many are dependent on other habitat for
specific time intervals. For example, hawks may nest in the
riparian-woodland areas but feed in other vegetative zones. The
wetlands are particularly important in providing the nutrients
28
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for the growth of micro-organisms which are the base of of both
aquatic and terrestrial food chains. The loss of wetlands due to
past mining activity and the potential for future losses during
remediation is an important ecological concern.
Previous studies at Clear Lake have identified seven species
of sport fish which live in Clear Lake. Upper trophic species
include largemouth bass, channel catfish, and black and white
crappie. Middle trophic fish include white catfish and brown
bullhead. Lower trophic fish include Sacramento blackfish and
hitch. Hundreds of fish tissue samples have been collected by
the California Dept of Fish and Game since the late 70’s; many
fish, particularly the upper trophic species contain levels of
mercury in excess of the FDA guideline.
A naturally occurring annual fish kill happens each year.
when the oxygen level in the water is too low for the fish to
survive. The carcasses of the fish wash up on the lake shores
where predatory and domestic animals eat the potentially con—
taniinated fish. Also scavenger birds such as vultures feed on
the dead fish. Tissue samples collected from two species of
birds at Clear Lake indicate a potentially significant ecological
impact of mercury contamination on the wildlife population.
Samples collected from the fish-eating grebes contained mercury
levels 70 times higher than those found in the strictly plant-
eating coots.
The toxic effects of mercury on wildlife has been widely
studied. In general, mercury is a known mutagen and teratogen,
which adversely affects reproduction, growth and development, be-
havior, motor coordination and sensory perception in birds, mam-
mals arid aquatic organisms. The presence of pesticides in addi-
tion to mercury tends to increase the toxic effects, whereas the
presence of selenium tends to counteract the toxic effects.
In fish species, signs of acute mercury poisoning include
flared gills, increased respiratory movements, and loss of equi-
librium. Chronic symptoms include emaciation, brain lesions,, ab-
normal and diminished motor coordination, erratic behavior, and
diminished response to changes in light intensity. Mercury tends
to be most concentrated in the liver, then the brain, and
thirdly, in the carcass. Symptoms of severe poisoning appear at
relatively high concentrations (5 — 7 mg/kg in the whole body).
Signs of mercury poisoning in birds include poor muscular
coordination, falling, slowness, fluffed feathers, calmness,
withdrawal, drooping eyelids and hyporeactivity. Mercury levels
in birds tend to be highest in the brain, then the liver, kidney,
muscles and carcass, in that order.
29
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In mammals, methyl mercury effects the central nervous sys-
tem, causing sensory disturbances and diminished motor coordina-
tion in acute exposures, to brain damage, mental derangement,
coma and death following extreme exposures. Additional symptoms
of acute exposure may include loss of appetite, belching, bloody
diarrhea, and piloerection (hair more erect than usual). In
general, -larger mammals tend to be more resistant than smaller
mammals. Mercury tends to be most concentrated in the fur, fol-
lowed by the liver, kidney, muscle and brain.
5.8 Conceptual Model
The Sulphur Bank Mercury Mine has been identified as the
most significant source of mercury entering the Oaks Arm of Clear
Lake. The Oaks Arm is the most contaminated segment of the lake;
sediments adjacent to the mine site contain mercury levels in ex-
cess of 200 ppm, whereas sediment samples in the rest of the lake
range from non-detect to only as high as 12 ppm. Fish from the
Oaks Arm also tend to have higher mercury levels than fish from
other arms of the lake. Mine wastes were directly disposed in
the lake, and erosion from the mine continues to contribute mer-
cury through mass wasting and fluvial processes. To a lesser
degree, groundwater migration of contaminants from the Herman Im-
poundment may also impact water quality. There are currently no
water supply wells downgradient of Herman Impoundment. The
potential also exists for mercury contaminated particulates to be
blown off—site. Mercury does not appear to be volatilizing of f
the mine wastes, however, this pathway has not been thoroughly
investigated.
The znethylation of mercury from contaminated lake sediments,
and the bioaccumulation of mercury in the food chain and ul-
timately the human population, is a primary concern. Numerous
factors influence the methylation process, namely the
availability of mercuric ion, and availability of nutrients for
bacterial growth. Additionally, the heavy algal blooms may in-
directly accelerate the methylation process by adsorbing inor-
ganic mercury to form complex ions, which are metabolized by ben-
thic organisms, become methylated, and enter the food chain that
way. The Oaks Arm tends to heavily accumulate algae blown in
from other parts of the lake by prevailing winds.
As natural springs may also discharge mercury into the lake,
the speciation and bioavailability of mercury contributed by•
these springs would need to be evaluated in order to determine
the significance of their contribution to the overall production
of methylmercury and the bioaccumulation of mercury in fish. If
discharges from submerged springs are at all similar to the
springs currently discharging in the Herman Impoundment, the sul-
fide ions contributed by discharged hydrogen sulfide gas would
30
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likely bind the mercuric ions, precipitating cinnabar rather than
forming methylmercury. In mine tailings, the roasting process to
liberate mercury vapor may have also been instrumental in
liberating mercuric ion.
6.0 Preliminary Identification of Remedial Alternatives
Remedial Alternatives for this site will be developed and
evaluated during the Feasibility Study, as described in Chapter
10. Remediatjon of site contamination will be dependent on es-
tablishing clean—up goals and standards, and results of the
ecological and human health risk assessments. The relationship
between remedial alternatives at the site and the actual reduc-
tion of exposure to the contaminants will be investigated during
the RI/FS. Bench and/or pilot scale treatability studies may be
needed to determine the effectiveness of proposed remedial alter-
natives.
Considerable work has already been done in identifying and
screening potential alternatives. The Abatement and Control
Study prepared by Humboldt State University (HSU) focused on two
primary objectives concerning remedial alternatives for the site:
1) Develop and evaluate source control alternatives to reduce or
eliminate future mercury contributions from SBMM to Clear Lake;
and 2) Develop and evaluate pollution abatement alternatives to
reduce or eliminate human and wildlife exposure to mercury al-
ready existing in the water and bottom sediments if Clear Lake.
The Abatement and Control Study did not consider or propose
remedial alternatives to address the impact of ground water con-
taininatjori from the Herman Impoundment. In order to ensure that
all potential contamination problems are addressed, EPA has
divided the investigation of the site into three parts, or
operable units (OUs). The Herman Impoundment, soils and mine
waste piles, and contaminated lake sediments will investigated
separately, and remedial alternatives will be developed and
screened for each operable unit.
The source control and pollution abatement alternatives that
have been identified to date are summarized below.
6.2. Source Control Alternatives
Effective source control alternatives will have to consider
the Herman Impoundment and the mine waste piles, and should focus
on reducing rates of shoreline erosion. A total of 12 alterna-
tives were evaluated during the detailed analysis in the Abate-
ment and Control Study and are listed below:
31
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a
1) Cut back the shoreline slope of tailing piles to reduce
erosion and prevent slope failures
2) Revegetate all or part of the mine waste piles to reduce
erosion
3) Riprap the Clear Lake shoreline to protect the base of the
shoreline waste piles slope from wave action undercutting
4) Grout the waste piles
5) Cap the waste piles with soil—cement
6) Cover the waste piles with a flexible geotextile
7) Cover the waste piles with a concrete blanket
8) Cover the waste piles with a webbed geotextile
9) Solidify the waste piles
10) Vitrify the waste piles
11) Excavate and dispose of the mine waste piles
12) Raise the dam and/or construct a spillway on the Herman
Impoundment to prevent overflow and dam failure
The Abatement and Control study estimated the costs for
these source control alternatives to range from approximately
$200,000 for slope cutback and revegetation to $250,000,000 for
vitrification.
Alternatives to address the groundwater pathway and the
physical hazards of acid in the Herman Impoundment were not
specifically addressed in the Abatement and Control Study, but
could include: no action, draining and plugging the pit, deep un-
derground injection of impoundment water, acid neutralization, or
installing barriers to restrict groundwater. Arty alternatives
considered for the Herman Impoundment will have to account for
the presence of natural springs.
The Abatement and Control Study concluded that source con-
trol alternatives should focus on reducing shoreline erosion and
on fluvial transport mechanisms for mercury contributions from
SB to Clear Lake. The study recommended a combination alterna-
tive of riprapping the lake shoreline, reducing the shoreline
slope to 20 degrees and revegetating to minimize erosion, and
raising the Herman Impoundment dam and adding a spi]lway and
channel, was recommended as the most cost—effective alternative.
The RWQCB has ordered the potentially responsible party (PRP) to
implement the erosion controls consistent with these recominenda-
tions. EPA will evaluate the effectiveness of measures being
implemented by Bradley Mining Company under the RWQCB Order and
will determine whether further measures are needed.
6.2 Pollution Abatement Alternatives
32
A
I ’
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The pollution abatement alternatives for mercury in Clear
Lake water and bottom sediments evaluated in the Abatement and
Control Study are:
1) Do Nothing
2) Implement a source control program on the mine site but do
nothing in the lake
3) Dredge the entire Oaks Arm or only the most contaminated lake
sediments
4) Cover all, or only the most contaminated sediments with clean
sand or clay
5) Establish a bounty system to remove contaminated fish
6) Periodically remove and restock fish
Costs for these alternatives ranged from $3,000,000 for
dredging or covering the area of greatest contamination to
$129,000,000 for periodic removal and restocking of fish.
The most cost-effective pollution abatement alternatives
will probably involve either dredging or covering the lake bottom
sediments in the Oaks Arm with clay or sand. These approaches
have proven to be satisfactory for sediment contamination
problems in other areas, but will require additional study to
verify their appropriateness for application in Clear Lake. Of
particular concern is that the ultimate costs and efficacy of the
lake pollution abatement alternatives can only be imprecisely
quantified at present. Since these abatement alternatives will
be very expensive, it is important that their costs and
likelihood of success be more accurately assessed during the
RI/FS. Understanding the mercury methylation and bioaccumulation
process in Clear Lake will be key in the development of a concep-
tual model for establishing sediment clean-up criteria that
equate to acceptable mercury exposure levels. The technical im-
p].ementability of these remedial alternatives will be studied
during the Feasibility Study, and may require bench and/or pilot
scale treatability studies to determine the potential effective-
ness of these remedies.
7.0 Data Management Requirements
The RI/FS objectives will be accomplished by collecting en-
vironmental data from soils, mine tailings, groundwater, lake
water and sediments, lake biota, and air. The quantity and•
quality of data required will be determined by the establishment
of Data Quality Objectives; the data requirements for the RI/FS
and are identified and summarized below.
7.2. Identification of Data Needs and Uses
33
‘ S.
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Sulphur Bank Mercury Mine - Mining Waste NPL Site Summary Report
Reference 3
Excerpts From Comments of Bradley Mining Company in Opposition
to the Proposed Listing of the Sulphur Bank Mine
on the NPL; Anthony 0. Garvin, Landels, Ripley & Diamond;
August 22, 1988
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1 I
( \1
CO1 (ENTS 07 BRADLEY 3WNI COMPMY
IN OPPOSITION TO THE
PROPOS LISTI OP
TEE ST3Lpj BMix NINE
ON THE NkT z PRIORITIES LIST
August 22, 1988
Aflt1 ø y 0. Garvj 1
Land.1 s, RipL.y &
450 Pacifie AVSZIU.
San Prancis 0 , CA 94133
Cou .t For Th.
Mining Compsn
.1.1_
-------
a
PRELIMINARY SThT t!NT
Th* Bradley Mining Company (‘Bradley Mining’) objects to the
:.S. Environmental. Protection Agency’s (“EPA ) proposed
esiqn.tion of the Sulphur Bank Mm. on the National Priorities
. .st VNPL ’) under rhe Comprehensive Environm-- .
Compensation, and Liability Act ( ‘C!RCLM), 4 :z /‘
212•; 53 Fsd.Req. 23988 (June 24, 1988).
Sradl.y Mining believes that EPA’s propos r
ranking of the Sulphur Bank Mine on th. NPL is / ‘
under CERCLA and EPA’s own regulations Line. t
of mercury and other inorganic chemical. are t
rta:ural, geothermal processes and not the resul
of the mine. Bradley Mining also believes tha
iu .sapplied the Hazard Ranking System ( ‘) S’) t
failing to consider all relevant data, making numerous inaccurate
statements, and using erroneous, unsupported assumptions that
skewed the results.
For these reasons, the Bradley Mining respectfully requests
EPA to withdraw its proposed designation of the Sulphur Bank Mine
for inclusion on the National Priority List.
II. DESCRIPTION OF TM! PROPOSED ACTION
On June 24, 1988, EPA proposed to add 229 new sites to the
NFL. 53 P.d.R.g. 23988 (June 24, 1988). The proposed list
includes the Sulphur Bank Min•. ., at 23995. EPA ranked the
Sulphur Bank Mine under group 5 on the proposed list based
i\Il\ -
1 \
.
-------
discharged some water tO nearby Clear Lak. during priods of
heavy rainfall, such discharges ceased in 1979 as a result of t .
construction of an earthen aam y Bradley Mining at the request
of the California Regional Water Quality Control Board.
Z Recent hydrogeolegic studies conducted by Columbia
Goscience on behalf of Bradl.y Mining indicate that the primary
source of mercury, arsenic and other inorganic substances in both
Herman Lake and Clear Lake is natural geothermal activity and not
surface runoff from mining waste. The studies conducted by
Columbia Geoscienc, were performed at the request of the
California Regional Water Quality Control Board pursuant to
S•ction 25208 of the California Health and Safety Code. These
studies are entitled “Herman Lake ?PCA Assessment, Sulphur Bank
Mine, Lake County, California” (1987) and “Mydrogeologic
Assessment Report, Sulphur Bank Mercury Mine” (July 1988) (“MAR
Repor ts). The MAR Reports contain site Specific data regarding
conditions at Sulphur Bank Mine which should be taken into
consideration by EPA in performing any assessment of the mine for
purposes of determining whether the mine should be ranked for
listing en the National Priority List. In order to facilitate
EPA’s reevaluation of the proposed listing of the Sulphur Bank
Mine, Bradley Mining hereby submits a copy of the MAR Reports and
Appendices and incorporates the data contained in these reports
as part of its c nts.
As mentioned above, the data developed by Columbia
Geoscience establishes that the primary source of mercury,
-3.-
F’
A
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1860s hays diituZb .d th . siarfac, of ths az*, tha i. ifting
activitisi hav not $iqftific*fltly altezid rh. nature or d.gr of
these releases. The data *1.0 di onstrate1 that the.. naturally
occurring relsass’ have nor cont1 DinatSd public drinking water
supplies and do not threaten to do so. For these reasons,
Bradley Mining .ub iti that it is inappropriate to include the
Sulphur Bank Mine en the National Priority List. Accordingly,
Bradley Mining respectfully requests EPA to withdraw its proposal
to add rh. Sulphur Bank Mine to that lilt.
.30 ..
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Sulphur Bank Mercury Mine Mining Waste NPL Site Summary Report
Reference 4
Memorandum Concerning Special Study Waste Support Documentation;
From Scott Parish, EPA, Office of Solid Waste and Emergency Response;
Hazard Ranking and Listing Branch; May 17, 1988
-------
A
/ I
I. ‘ — . . V
tQ S? 4
I UNITED STATES ENVIRONMENTAL PROTE T1ON AGENCY
WASHINGTON. D.C. 20480
4 ’ a,’:J ’
occ cE oc
)4AY 1 7 T9 SOIJO WASTE AND EMEIGENC ESPOP
MEMORANDUM
SUBJECT: Special Study Waste 5 ’
FROM: Scott Parrish, Chi.
Hazard Ranking and
TO: The Record
Until the Agency’s Hazard Ranking System (ERS) is revised,
Sections 105(g) and 125 of the Comprehensive Environmental
Response, Compensation and Liability Act, as amended by the
Superfund Amendments and Reauthorization Act (SARA), require
EPA to consider certain additional information before sites
.uvuiving special study wastes may be propo d for inclusion
on thQ National Priorities List (NPL). Special study wastes
are defined under Sections 3O01 b)(2) and 3001(b)(3)(A) of the
Resource Conservation and Recovery Act and include_tb .._f.o.U
categories of wastes: drilling fluids, ‘produced waters, an4.
ër wastes associated wi.tn the exploratior evelopment .
production of crude oi,l or natural gas,lly ash, slag, and flue
gas emission control waste generated primarily from fossil fuel
combustion; cement kiln dust waste; and flolid waste from the
xtract1 n, beneficiatiori. and processing of ores and miner Ts .
EPA has determined that the final category listed above includis
coal tars from coal. gasification plants and spent pot liners
from aluminum production.
Before sites containing any special study wastes except
fly ash, slag, and flue gas control wastes can be proposed in
Update 07 to the KPL, Section 105(g) requires that the following
information be considered:
— The extent to which the ERS score for the facility
is affected by the presence of the special study
waste at or released from the facility.
— Available information as to the quantity, toxicity,
and concentration of hazardous substances at, or
released from, the facility; the extent of or
potential for release of such hazardous constituents;
the exposure or potential exposure to human popula—
I ”
Branch
A—9
-------
—2-
tion and the environment, and the degree of hazard
to human health or the environment posed by the
release oe such hazardous Constituents at the faci1it .
Section 125 presents the requireme 8 for listing fly ash, slag,
and flue gas emission control Wastes. No sites in Dpdate #7
were scored based on this type of waste.
To comply with Section 1 O5(g) of SARA, the Agency has
prepared addenda that evaluate the information required for
each proposed site having or Potentially having Special study
wastes.
The special Study waste addendum for this site is attached.
It indicates the Special study wastes present a threat to human
health and the environment, and fujfjlis the requjreme 3 of
Section 1 05(g).
Attachment
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SAMPLE ANALYSIS FOR
SULPHUR BANK MERCURY M!WE
CLEARLAKE OAKS, LAKE COUNTY, CALIFORNIA
1. Introduction
The Sulphur Bank Mercury Mine (SBM) is located on the east shore
of the Oaks Arm of Clear Lake, Lake County, California. Mining of
mercury at the SBM began in the late 1800’s and continued on and off
until 1957 using underground and open pit methods.
The mine site contains approximately 120 acres of mine tailings
and an open, unlined mine pit (called the Herman Pit), which Is water
fifled up to 150 feet deep. Mine tailings extend Into the Oaks Arm of
Clear Lake along 1320 feet of shoreline. The Herman Pit Is
approximately 23 acres in size and located 750 feet uogradient from
the lake. A drainage channel with a flow of approximately 20 gallons
per minute (GPM) leads from the western edge of the Herman Pit to
Clear Lake (Ref. 5).
2. InformatIon on Constituents of Wastes
quantity . Evidence from site inspections conducted by the
California Central Valley Regional Water Quality and Control Board
(RWQCB) and interviews with state agency representatives Indicates the
primary wastes disposed of at the site are mercury bearing mine
tailings (Ref. 8, 9). These mining wastes are classified as special
study wastes under RCRA Section 3001 (b) (3) (A) (ii ). Therefore, all
wastes at the site are special study wastes and all threats fran the
site are due to special study wastes.
Sampling conducted on-site Indicates that the tailing piles
contain elevated levels of mercury and arsenic. Water contained in
the Herman Pit also contains low levels of mercury and arsenic.
However, because the pit receives water naturally containing low
levels of mercury arid arsenic through a geothermal vent located at the
base of the pit, it Is impossible to distinguish contamination
emanating from the geothermal vent from leachate derived from the
surrounding mine tailings. Therefore, the water-filled Herman Pit is
not included In the total quantity of on-site waste. Based on the
existing on—site mine tailings at the site a minimum of 193,600 cubic
yards of waste are estimated to be on-s ite.
Sediment grab and core samples taken from the lake bottom indicate
that the lake bottom area within a one-half-mile radius of the mine
site Inculding most of the Oaks Ann of Clear Lake contain elevated
levels of mercury in comparison to other areas of the lake (Ref. 10).
Concentration . Eighty-nine tailings samples, eight sludge
samples, and 23 mine pit and drainage surface water samples were
collected at the site and analyzed for mercury and arsenic. All of
the samples were analyzed for mercury content, while the only samples
-------
analyzed for arsenic content were the surface water samoles.
Currently, analytical data are not available for arsenic
concentrations in soils at the mine site or in lake bottom sediments
(Ref. 10, Attachment 1).
Mine tailings at the site contain mercury with concentrations that
range from 1-624 mg/kg and have a mean concentration of 60 mg/kg.
Sludge samples from the Herman Pit and drainage area range from 45-260
mg/kg mercury and average 143 mg/kg mercury. Surface water that
drains from the mine pit downhill from the facility and enters the
lake contains mercury at 0.203 mg/i and arsenic at 0.303 mg/l (Ref.
10, p. 1 and Attachment 1).
RWQCB analyzed lake bottom sediments within a 1/2 mIle radius of
the mine site and detected mercury levels with an average
concentration of 102 mg/kg in the surface sediment samples. Levels of
mercury in the sediments from other arms of the lake ranged from
undetectable to 3.0 mg/kg mercury in the Upper Arm and 7.6 mg/kg
mercury in the Lower Arm.
Department of Health Services (DOHS), Department of Fish and Game
(DFG), and RWQCB analyses indicate that levels of mercury are present
above background in the blota and lake bottom sediments in the Oaks
Arm of Clear Lake. In addition, the levels of mercury in fish from
Clear Lake are such that the DOHS issued an advisory aoainst the
consumption of fish from the lake on May 14, 1986 (Ref. 5).
Thorough sampling of soil, sediment, and water in mine tailing
piles and surface water around the site, in addition to samples of
lake bottom sediments and lake blota in Clear Lake have been carried
Out for this site In the course of site investigations and routine
samoling since 1970. Results of these samplings serve as the basis
for the concentration data used In this analysis.
Toxicity . Toxic compOunds of the mine tailings and pit water
found at the site include mercury and arsenic. Both of these
contaminants were determined to have the same combined toxicity and
persistence score on the Hazard Ranking Systen (HRS). Mercury and
arsenic are listed as highly toxic In Dangerous Properties of
Industrial Materials (Ref. 11), the standard reference for toxicity
classification in MRS scoring. These contaminants are also
persistent, which would give than the highest MRS toxicity score of 18
(Ref. 11).
The maximum concentration levels (MCL) for mercury in drinking
water Is 0.002 mg/l (Ref. 15). Mercury Is found In the surface waters
of the Herman Pit and associated surface drainages at concentrations
100 tImes higher than the MCL (Ref. 10, IS). The concentrations of
mercury found in the surface water at the site is over four orders of
magnitude higher than the EPA chronic fresh water aquatic toxicity A
criterion for mercury of 0.012 ugh, and almost two orders of magn1tu e
higher than the acute fresh water toxicity criterion for mercury of
2.4 ugh (Ref. A).
The MCL for irsenic In drinking water Is 0.05 mg/i (Ref. 15).
Arsenic is found In the surface waters at the site in concentrations six
—2—
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Sulphur Bank Mercury Mine Mining Waste NPL Site Summary Report
Reference S
Hydrogeological Assessment Report, Sulphur Bank Mercury Mine,
Clear Lake, California; Prepared for Bradley Mining Company
by Columbia Geoscience; July, 1988
-------
NDROCEO C ASSESS q. PZPOR
STJLPKJR ZANX M C y MINE
CI.EAR LAICE, CALIFORNIA
JULY 198$
For: 3R MININC COMpANY 3y: COUJMJIA CEOSCI CE
SA1 FRANCISCO CALI7OgN HII.L,$$ORO OREGON
A— 3
-------
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6. SUVACZ WATU. . Continued
6.1 Clear Lab.
6.1.2 .eieal Charletsri2atiolt
CLEAR LAZE IS A WARM. VJ71 PRZC F?ISRWATZR LAZE WITH HEAVY
71ZENT LZVEI.. MD sr’ru ALGAE c rx. ttwzvzz.y RICH 1O N
AND L.TTN1Z LEVELS VJCCEST I X ? ? . ! ? FWM Nor sn.rxcs • SIMILAR PERHAPS
TO THOSE TRAY FORMED THE MERCURY ORE DEPOSIT AT SUZIRUR lAWN.
?.ECZRT MERCURY PSOFIW ZR CLEAR LAZE AVERAGED 41W? .0005 MG/L.
Th. water in Clear Lake can be described as relatively warm vith
substantial. concentrations of mapt.stia and caLct carbonates
(Table 6.1.2.1). The pH is typically in the rang. from 7.5 to
9.0. The Lab. is quite turbid during ths fall, winter and early
spring as a result of seasonal r a off and vtnd .tndunsd aixing,
whil, in the late spring and s r clarity improves
considerably. Stratification occurs during short periods in the
s er with a v.11-mixed layer near the surface where oxygen
levels are reasonably high and an uraiz.d layer below causing
anaerobic bottom conditions. Cenzid.rabls nutrient
concentrations, related principally to runoff from the drainage
basin, sustain high levels of alga. growth which is a primary
water quality concern in Clear Labi.
Boron and tithiue concentrations, probably related to thermal
springs, have been noc.d to be relatively high, with Boron
occasionally exceeding standards for irrigation of sensitive crops
( ). Mercury is generally non-d.tectable or at trace levels.
but relatively high concentrations have bean detected in certain
species of fish from the Lake, and in boctoa sediments. According
to Charles Chamberlain of H .abolc State University (personal
co unLcation to the Board 20 July 1913, Fig. 11), profiled
mercury concentrations at 2 sites in nearby Oaks Arm of Clear Lake
en 17 June 1$ ranged ft.. about .00025 to .00123 aaJi. The
apparent av.rag. concentration is about .0005 mg/i. The presence
in Clear Lake waters of boron and lithi a, and lithiia/chlortda
ratios nearly identical to those of Herman Lake and th. thermal
springs that feed it (bottom of Table 6.1.2.1), suggest a coon
origin .f regional scale for both the boron, lithiia, and the
mercury.
According to NcLmag}ilin (1931), a large mapa chamber dirsetly
w d.rli.s the Clear lake basin (Fig. 6.1.2.1) at a depth of about
25 miles. This is the basic driving force for upv.lttng
mineralized fluids and gas in the region, and Li responsible for
the continuing inf1 a of mercury into Clear lab . basin and into
Sulphur Bank.
23
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6. SUPiAC& Warn.. :tnued
6.2 Xu lake and Tharsal Spring.
6.2.1 b..erfn tan a nd Ch.eicil Character
HERMAN LaXE IS A WELl. MiRED GEOTHERMAL L .4U CONTAINING ACID WATER
WITH NIGH CONCENTRATIONS OF SULFA2Z • SODIUM. CXW*IDE • JOH N.
AJV ONZA. AND TRACE MERCURY CONCENTRATIONS 07 .00081 MC/L. LARGE
VOWIf ES OF GAS CONTZNOUSLY JOIL TR UGR THE Orfcrg-P.IcH W471R.
CREATING A RICHLY REACTIVE £ VI NMV4T FOR PRECIPITATION OF
DZSSO2..VZD METAIJ INCIJIDING MERCURY.
The chasistry of Herman Lake. it. bottom sediment and th.
submerged thsrsal springs. v.r. fully characterized in the 19S7
TPCA assessment report by Col abta Gosciencs. Hovever. in ordar
to provids continuity, vs bay. included in this r.port ths tvo
TPCA analytic chonistry tables (Tables 3.1-1 and 3.1-2), and a new
analytic chemistry tibia siarizing the l9$$ MAR data (Tabi.
6 1.2-1). This table also contains a s sry near the bottom, of
all published analytic data on the submerged tharmal springs, and
several analyse. of Clear Lake water. Thermal vicar analyses .26
.29 and .30 of the TPCA report were not previously ovn as to
sampling location; however. th. old bathhouse hot vicar veIl (.26)
has bean id.ntlfied from old maps and plotted as Well 3011 (Plate
3. north sid. of Herman Lake, site now submerged).
Analysis .30 (TPCA report) has nov been identified as G.ys.r
Sprin$, north 514. of Herman Pit, cl iv. 1230 in 1957 (White,
1962. Table 1). and is includ.d in the 19U Analysis .29
(TPCA report). similarly is identified as being in Herman Pit
sotithvst of a spring (W4) on th. north sid. at .1ev. 1225.
Although specific field locations era not provided, it La obvious
from the elevations in Whit.. Table 1, of 1220 to 1250, that his
analyses vets all vithin th. deepest .zcava:Lens of the
impourtdeuit. His field descriptions and te eraturs data clearly
demons crate the .i’ ra1izsd character of these hoc springs. The
springs vets of peat variety. with temperatures tap to 77°C, and
frequently guckarpd. Dsspits the n .r of hot springs, White
.stiaet.d total thermal spring flow of about SO gal/sin during pit
d.vEt.risg. The highest mercury concentration detected was
0.20 pp. is ‘Ink Spring’ on $ovsab.r 9. 195$. or about 10 cLass
higher th an earlier asssureasnt of .02 pp. (Table 6.1.2.1)
(Whit., 1962, p. 415). White speculated that a p14 difference
(6.6 vs 4.1) caused the variation or that mercury vu sore
ezcanstvsly precipitated by sulfide dissolving in the relatively
cool, spring pool fre, rising gases (July 6. 1955).
24
-------
U
, 0 -
6. SURZACL W&TD ..Contjmad
6.2 Ns i Zak. and Th.r al Springs
6.2.1 beaeri tien and Chemieal Charaet.r..ç
During the TPCA fieldwork, 9 samples of Nerm . Lake eater
cell.ct.d from various d.ptha (Tabi.. 3.1-1,2) had aver . 1 . mercury
cencsntratjo of .00081 mg/i with a range of .0036 tø .00025
mg/i. At the time of sampling, th. lake v.a eel]. mixed and
od.racely Oxygenated dui to vind and large ‘ol .e of gas
discharge thyough the bottoa sediaento. Analyses in
Tables 3.1-1,2 shoe that Herman Lake eaters are rather exotic etch
u 1>. high boron/chlori ratios and variou.s ether ion ratios
such as litht a/eh1erj that are essentially idntjca l to the..
of the hoc springs (see also sI ary on charm.], springs in
Table 6.1.2.1).
In general, Herman Zak. is typically a veil mixed acid eater body
(0.0. 5 mg/i, pH 3.1), etch high eoncencraci of sulfate,
sodi , chioTid .. boron, aonja. calcj and uagtesi . Large
ve1 aes of gas (CO 2 . methane, n2.:rog.n end H 2 1) constantly
boi,i, he water surface in many areas of the lab. (see TPCA
report).
Such Conditio j in the presence of wall.. ygisnaced hLjhiy
mineralized acid eater, helps maintain a highly reactive
envjre nc in which precipitation and dissolution reaction,
probably occur with hours or ai uc s.
On the baa La of eater geochemistry Herman Lak. La a geothermal
lake fed by subsurface hot springs, with dilutj by rw off and
rainfall. The sa3e processes that produced the mercury ore
deposit during the past 40,000 years or so is still active end
largely responsible for dpositio of mercury in bocto, sediments
and the aLntenar e of crace levels of mercury in the lake waters.
25
-------
D ftU & A&
7. VELL3 VITRIjI 1-MILE 1AD!US
7.1 M.uby Wit.r Veils
NO VSZ ISTIC. STXI. OR PUl l -IC 7ppi.y vzzz,.ç
DaPNCR iJz .DT OP TNt WIPRUR J4NX RINZ
Sulphur lank Nina Is bound.d on the north and vest by Clear 1aka,
and on th. south by Steap So mtajn ridga vith. .07 ksovn
inhabitant.. To the north .ist, Cl ,a lak , Oaks Vato District
supplies eater to .o.t of the nearby eQ jtj.s, including th.
£1 . . Indian Colony northeast of cbs am.. Only ceo dosestic veils
(PV3, PV4) and three irrigation v.11. (PVi, W2, and 1N4), are
to be in use vithia a i-oils radius of the ipo doet
(Fig. 7.1.1). N senicoring v.11. hav, also bean drilled in
the vicinity of th. Clearlake Oaks vaste eater ponds to aonicor
leakage northeast of Sulphur lank Mine. Many of these have bean
located and osasured, and used to assist in Rapping the regions],
ground.va:.r floe sys:..a (Fig. 7.1.1).
In general, v.11 logs in the area effstte shoe that th. C1ear1a
Oaks vast, eater ponds ars excavated into a uod.rately per .ab1 ,
shsilov vatsr.gable aquifer consisting of alluvius Coap unit Qs in
this report) about 13 feet thick, rssting on fractured,
scoriaceog , basalt (Qa) at least 80 feet d..p (veil log PW2,
Appsn4 I S.c:ion 13.3). Croundest.r ho. irrigation veil 2 is
ussd partly to supply a stock pond on the Ito. property Just
north’,,.: of oonitor ng veil 5110. Most of cbs Ion itoring veils
near the vast. vator ponds are shal]ov and do not penetrat. the
und.rlyin.g basalt floe.
The growt .va , surface and floe direcei .app.d in April 198$
danon. ,trat. that existing eater supply veils in the region ca ot
be affected a 7 ground.va . transport of conta i ant. fro. the
Sulphur lank Kin, property, Tea public supply veils op.rat. by
Cloariak. Oaks Water District are locst.d on the shore of Clear
Laka northeast of Stubbs Island, sore than one oil. fros Sulphur
lank Iapow nt. The veils are reported to be less than 70 feet
d .ep, and beca s, of the nature of ground.vator floe at the sit.,
they c’ ot be L iact.d by the Lupoundos t•
31
-------
Stubb* island
IIAN411ER1
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7. WILLS VITHIJ 1 -MILL UDnIS. •Centiaa.4
7.2 e.iul aruur Of Water in Isarby Ve l 1s
NXIffU icvrrwzo,’s ZN VATU r ‘ y wzz.z.c vrz , j ’ o,
THE D1TZCTZ v LMZT. VATIR CNZMZST, DiTA ZNDzc tj’jg rw ig, jy
WZLZJ TAP C. uN vA2U OF NOV-TZWgaz, o*zczzv.
Covpr.benstv. gTowld.vater cbesist y hu bean deterRi .d for five
vat.r veils in the area (FIg. 7.1.1, veIls PV1, PVI, PV3, 11(3,
11(4). Field ch a nts try aeaaure.ex (p11. to eratu e, and
•isct jcai conthactiviry) vex. miae aad. and axe Included in
Tabli 6.1.2-1.
As the contaaine of primary interest, marcury concentra j. in
all veils v.re beiov the detection limit of .0002 ag/] ., szcspt La
vater from ths wnased Eradley Mining Company veil 1113 which vms at
the detection limit. In general, cbs inorganic quality of water
ire. thue veils is suitable for most purposes and may be
charact.riz.d aa slightly acidic (pM 5.11 tO 6.26),
growtdvac.r with total dissolved solid., (TD$)
concspera:i ranging from 312 to 140 mg/l. Three veils (PV3,
11(3, 11(4) slightly ezc..d secondary vatsr quality standards fox
TDS of 500 mg / i. All nearby veils draw growidwater from various
rock types in the depth range of 0 to 105 feet. The trace levels
of boron, lLthit , sodita, chloride end onia, coupled with ion
ratios show that i r e . these veils is no: of deep-seated
thermal origin.
32
-------
QJJ1( & MNE NINE HA&
$. !m .VATU K IDLCCY
$.l Sulpbia lank Geology
/! .plUl L4JIX MINE IS SITYJA1’ED AT THI ZNTLpJg fl J 0? SIVUAL
R2 ZONAL FAULTS All V £$SXIAT SHEAR ZOJILS vIZct SWI AS AVENVES
FOR UPVA.W 71W or HOT MINFJALZZIN WAlER AND QAS. T&4NCISCAN
3ED Z. QUATERNARY SZVZNIZ’TS. AND 4 TCUWC AWDSSITE Z.4V4 PWl WERE
AIMED FOR ? ERCURY ORE V L4CZD WRING THE PAST 34,000 TEARS.
Clear Lak. basin lies in an active hinge greben structure. The
basenent rock in the aria is !!casciscan ?orsarton,
cosp.a.d of aecreted s.dinents. In th. Sulphur lank ass late
Pisistocens lactistrine and terrestrial udisenca imconforaably
ov.rlay the Franciscan Foramtion, thickening to the vest toward
Clear Lake and pinching out to the ease. I te Pleistocene
anduitic lava has flowed ever the aedtasnta and Is currently th.
upp.rsoat rock ie in nest of ch. central northern portion of
the ama property (Fig. $1). Locally in low arsas northeast of
the sine, soil davelopsent and amer sediesneation obscures the
snd.aie. flow. Hot peth.r.a l fluidi ascending along vertical
faults and fractures have caused alteration within each of the
rock types present in the sine area and to seat in an area
vpgradiant Eros the aining property. The ascending g.oth.rsaL
fluids are the carrying aechani,. by which aercury is being
brought into th. area. Earning era deposits where the degre. of
aineralisatien is nost concentrated, as in the shear zones.
Details of these structural features and geology of Sulphur lank
Nine are incl ad.d on Plate 1 (pocket). Geologic cross sections
and th.rsal gradients contours in the sine area an, included
within the following foldouti as Figure. 1.1.1 through $1.5.
5.1.1 Fravtefaeg,t To satjan (LJf
In the Sulphur lank ares the Franciscan Pornation Is couposed of
contor t ed b eds of paywsck. black shale with local
cbert.b.arjng zones. tvtdsncs of low-grad. aet rphisa is
present throughout. In the eastern portion of th. sine property
-and apslsps seat of the sins property, kaolthite/bslloystte and
hydrous owUaz. alteration of Franciscan rocks is observed. Thea.
whit. ass es St incense alteration (Ti;. 5.1.1.1) are often
associated with the sash of sulfur .bsaning gasses, no vegetation,
and are the result of .n.going alteration caused by discharging
high-teuperacure ;eotherasl fluid and gas along dssp . .satad fault
zones.
33
-------
5. aou D .vAm Y I0LXY Conti m4
1.1 Sulphur lank Geology
£ZCAVAT 1A**fN V / iTt CZ PILlS X PPT A1 ff 1 ACZIS W’ L ND
JLP1U1 JANZ. TAILINGS Dt&IV F M AZZJ. AND AS W
ORt.JLWNC Ct F WHZ N tRCVRY V /i WZ# TW • XV I I AIX?
.27 ACRES.
$14 Va.r. leek Pilci (l11v
The saterial .aktn$ up the sins piles consists predasinsatly of
overburden and barrsn rock rsnev.d true the sins shifts aM open
s csvstton1 free 1165 to 1957. The tsr. gg g_3 g is forsally
defined within the sintr*g .rgi ift Ig professiob as ‘ValuaIiii.
rock that suit be fractursd end rsaoved in order to gain access to
or upgrade .rs. (KcGrav .HLl1 Dictionary of £arth Sciences. 1984,
p.51 .6). .
That usage is fol.low.d her. and such usage should net b. cons rusd
in any way to represent industrial vests products and
concastn.ancs. The .at•rial ranpi in sic. fr .. clay, silt and sand
of pr...nd.sit. aadiaent.s to aM.stts boulders up to about 3 fast-
in dia..car. Tb. specific size range, .rig&n. aM extent of
d.ceapesttton is szzr...ly variable both vertically and
horizontally thro ag out the waste piles. Tb. greatest percentage
of th. rock seking up the piles is snd.sit.. The degree of
alteration observed within the andesit. in the vests reflects the
sane wide range of alteration observed in w szcavscad outcrops of
andesit.. Clay alr..retien within the tsp 10 ca. of the pile.
surfac. is coueen, resulting in reduced infiltration capacity and
add.d r moff during heavy rains. Waacs rock piles cover about
90 acres of the sins property (Plate 1) and extend beyond the 1911.
and 1927 shoreline .1 Clear L ake (PLate 3).
1.1.5 Tailing. (IMt
Tb. tailings piles consist of cr iabed and routed or..grad. rock
free whish nerc y was extracted. Tb. tailings consist of silted
rock ranging in sic. ft.. silt to rock frspsnts teas then I ca.
across. Oft.. th. piles zhibtt b.ddsd atnsc .. reflecting
aseP ical sticking and grading. Tailings ire. the earliest
mining activities are often ai d with charcoal, reflecting the
tias vb.n the fuznsc.a vase operated with weed rather than oil.
Perneability aM initleracton capacity within the tailings pile.
appears to be such biter than in the vast, rock piles. Tailings
cover about 17 acres of the sins property (flats 1) • aM probably
var. excavated during later mining along th. south side of )Ier.an
lab. .
3’
-------
SULPEtJR WIX MINE HAR
L GROUND -VATs HYDROLOGY.• C ntinu.d
$ .2 la ionsl Crow dvatsr Flow System
SULPHUR AHE MINE IS S J.t ED WITHIN A JROAD REGiON OF SRAUA72
GF UND-WAiER Fl ’ THAT MIGRATES NOZTWARD F.Wn STEEP MO11 TA1N
FWbTS TO CLEAR LAKE. WCAZ.LY AT SULPHUR lANK MINE. SHAUi7-’ AND
DEE? -iEATED GP.OUNDWATER SEEPAGE PiOVES DZP2 TLY Zifto NEM LAE.E
AND WESTWARD T t#J.D CLEAR LU E.
The regional ground-water flow system to the Sulphur lank Mine
area consists of a relatively shallow flow system driven by
rainfall and gravity, a. exemplified in Pig. 7.1-1, arid a
dasp.seat.d, pressure-driven geothermal syste. at Sulphur lank
Mine that cannot be shov suLly in plan view. The ground-water
surfac. on is based en shallow wells which g.n ral1y penetrate
less than 100 feet of moderately permeable a1luviu and lake
sediments about 15 feet thick, overlying a fractured andesictc
basalt flow, perhaps 100 feet thick. The Clsarlake Oaks vast.
water ponds northeast of Sulphur lank Kin, appear to have formsd a
alight mound in the regional flow system and seas divergence in
ir.cttons of ground-water flow. However, the predominant
directions of ground-water flow are directed towards Cls.r Lake
from the surr.undirg te ; mountain fronts.
Locally at Sulphur lank Mine, excavations beneath Herman Like have
accentuated the westward flow of groundvat.r as shown by the
1340 foot contour which nov .ncompasses and surrounds Herman
talc.. Under native ground-water flow conditions prior to the
start of mining in 1863 the 1340 slevacion contour would have
closely followed the 2 .330 contour vest of Sulphur lank Mine. In
place of Herman Lake, desp.seat.d upv.Utng geothermal fluids arid
gas, still in obvious abundance in Herman Lake, would have been
forced to ris, to higher levels in the rock mass to find exit
points and migration paths to Clear Lake. Field evidence on the
Lportancs of the water table in controlling mercury ore
deposition at Sulphur lank (White, 1962) suggests that at some
point the vacer .tabls was vithin 15 feet of the oviginal land
surface. The present surfacs of the and.sit. flow at Sulphur lank
Mins is mors than 1,400 feet in elevation, suggesting that the
native groi d-vatsr surface o ne. contained a mound approximately
located at the north side of Herman Lake, at about 1,400 fast in
.levation. The deep-seated vertical pressure gradient still
exists, but an infinite east-vest permeability zone now exists
(Herman Lake). This has allowed th. tounded ground-water surface
to dissipat, and decay to the level of Herman Lake.
41
-------
SUL.PHTJR lANK MINE MAR
8. HYDEOLOCY. -Continued
8.3 Sulphur 3a 1 k Ground-Water Flow System
AT SCI(! TIM ! IN T N! AST, NATi’IE CROVND-WATD P1W AT SULPHUR lANK
MINE WAS DCPIINATED IT A T I ALLY.PtD 0UND-WATD MOIflID ftEA INc
ELEVATIONS CLOSE TO 1400 FEET. HDIIAN TAlC!. AT ELEVATION 1334,
HAS SUIMERGED THE THERMAL SPRING V ITS AND ACTS AS A MAJOR
DEPRESSION IN THE LOCAL GROUND-WATER SURFACE.
The ground-water potentiometric surface at Sulphur lank Mine and
direetjo s of movem. are shown in Plate 2 (pock.t) and in $
series of cress-s.c:ion s (Fig. 8.3-1,2,3,4) on the following
pages. Othsr relevant figures include the •pi llvay axis section
(Fig. 4.2-1), and a sap shoving th. regional flow system
(Fig. 7.1-1). The ground-water surfac, contours of Plate 2 ars
based on well seasures.nts in late April and early May, 198$.
Herman Zak . and Clear Lake wat.r surface elevations vera 1334 and
1324 f.et respsctiv.1,y on April 4, 1988 (th. dat. of aerial
photography aged in constructing the bas..ap). Thes. elevations
yen, used in sapping th. ground-water surface and may b. expected
to vary seasonally in elevation with a typical head difference
ranging from about 7 to 10 feet based on 1987-88 data. During
severe winter storms that affect both lakes, th. head difference
during short p.niods say be as low as 3 f..t (1335-1331). lecause
these two lakes are the major ground-water sinks tn t th. area, the
adjacent ground-water surface viU tend to fluctuat. roughly in
proportion to changes in th. levels of Herman L.k and Clear Lake.
Th. ground-water surface contours of Plate 2 represent a period of
near maxim head difference (10 feet) and therefore maxiaia rates
of ground-water sov.mene from Herman Lake impoundment to Clear
Lake. Configuration of the water-level contours show that Herman
Lake iapoundaent receives (in addition to deep-seated flow from
submerged thermal springs, shallow ground-water seepage from the
north, east, and south. Seepage escaping fro. the impoundment
migrates westward to Clear Lair, , however, as shown by the davnvard
slope of the ground-water surface from the vest wall of Herman
Lake to Clear Take (Figs. 4.2.1 and 8.3.3). The spt].lway axis
section represents the shortest and steepest ground-water flow
path fro, the impoundment to Clear Lake. For the conditions shown
(10 foot head difference), th. ground-water gradient works out to
about 73 feet per mile over a distance of 720 feet. Gradients
along the longest flovpatha to Clear T.a e of about 1,000 feet, are
about 54 feet per mile. La will be shown in section 8.5, the
average rate of ground-water movement is extremely slow and the
seepage quantity is relatively smell.
43
-------
Sulphur Bank Mercury Mine Mining Waste NPL Site Summary Report
Reference 6
Herman Lake TPCA Assessment, Sulphur Bank Mercury Mine,
Lake County, California; Prepared for Bradley Mining Company
by Columbia Geoscience; 1987
4,
-------
I RI AN LAJ ?PCA ASSESs ,
SULPMUR MIIX MINE,
LAJ COUNTY, CALI?QRN
fez th.
BRADLEY MINING COMPANY
by
Co1 bj. Gsosej, ,
1987
-------
I RMAN LAJ TPCA ASSESSM N ’.
SULPHUR 8A C I1%NZ
LAJCE COUNTy, CALZ?OR1
CONCLUSIONS
1) The Herman lake water 5 found to be below toxic limits for all Title
22 catageri.s of the Toxic Pits Cleanup Act. Ths sediments at the bottom
of the Herman lake is found to be below toxic limits for all catagories
other than mercury.
2) The values for mercury observed in the sediment cores from the Herman
lake are among the lowest mercury eonsentratj s observed for sediments
an the Oak Arm area of Clear Lake.
3) Five of the nan, sediment core taken from the Herman lake show mercury
an excess of the 20 ppm limit for toxic pits. The Mercury concentrations
rang, from 9 to 46 ppm and average 26.3 ppm for the nine sediment
samples.
4) Analyses of water fractions from the sediment cores show the pore
water to be well below the toxic limits.
5) Mercury is flOt found to be leaching from the Herman lake sediments
anto the water.
6) Herman lake is currently acting as a natural treatment process to
impound mercury which may enter at.
—1—
-------
m. water chemistry prof iles (temperature, Conductivity. an
dissolved oxygen), confirmed that the entire water column was extremely
well mixed throughout with a temperatur, about 20° C, dissolved oxygen
about S ag/i, pH about 3.02, and specific condUctivity about 6,600
micro s/ ce. • Lb measurements at profile sit. P2 were 791 my at is, 763
my at 9m, and 762 my at 23m. Measurements of the 9m and 23m depth water
samples were made by inserting the Lb probe into the rubber drain tube at
the base of 2.5 lite “ai. Dorn sampler, immediately after bringing the
sampler to the surface. A slow flow of water was allowed to drain across
th. probe during each measurement. Stable readings were Obtained within
about 2 s nutes.
TPCA C ttSTRY
waters of Herman Lake
The field investigation of the waters of Herman lake, has failed to
detect any violations of the Caljforni,a Toxic Pits Cleanup Act.
Persistent and bioaccumulative toxic substances under paragraph 66699
(Title 22), including organic and inorganic substances ware undetectable
or at concentrations far below those required to trigger action under the
current hazardous waste criteria (Tables 1 and 2). Notably, the average
concentration of mercury was only 0.00081 mg/ i in 9 samples of Herman
lake collected in August and November, 1987 (Table 2, samples 1 through
9) • The range in mercury concentrations V55 0.00380 to 0.00025 ag/ i
(i.e., deep water at 23 meters versus shallow water at 9 meters, profile
P2). The deep water sample at P2 is the only sample in Herman lake that
exceeds the EPA drinking water standard of 0.0020 ag/l mercury, and at is
about 53 times lower than the STLC trigger level for hazardous waste (0.2
mg/l).
The November samples as shown elsewhere in this report, represent
well—mixed, moderately oxygenated lake water recovered from various
regions and depths in Herman lake. it is possible that Herman lake
becomes moxie at certain times of the year, thus increasing the
selubility of mercury. The 1976 June sample (#12), suggests some
increased levels of other metals and anions, but mercury levels and the
exact loeitje of the sampling site are not providsd. The 1987 August
samples by the bard on the other hand, show that. the water chemistry at
Herman lake remained nearly identical into the November sampling run,
despite crossing • typical time of the year when most lakes turn over,
causing a mixing of cold, anezic bottom waters with warm, oxygenated
shallow water. Mcause of the prevailing west wind and the large volume
of gas discharge from bottom vents, Eerm Lake probably remains
veil-sized and moderately oxygenated except on rare occasions.
Therefore, the 1987 chemical characterization of Herman lake by the board
and by Coli.bja Geoscience, probably is representative of the overall
long term physical and chemical conditions at Herman lake.
110
—22—
-------
Bottom S.diaents of Berman Lake
The field investigation of the bottom sediments of B.rman lake, his
shown that S out of the 9 ore .ampl.s contain elevated ?ILC a.rcury
concentrations ranging from 21 to 46 mg/kg (Table 2), which is sufficient
to classify parts of the lake bottom sediments as hazardous waite (20
eq/kg). Pour cot. samples contain mercury concentrations ranging from 9
to 19 eq/kg. The average concentration of mercury in all core samples ii
26.33 mg/kg, or slightly in excess of current hazardous west. criteria.
Leachable STLC mercury concentrations in all cores were at trace levels
or below the detection limit (see original lab sheets appendix B) • All
other inorganic constituents classified under the TPCA were also at trace
levels or below the dstectQn limit.
All coring sites shoved •videnc. of anoxic conditions within the
s.dimsnt (black to dark green colors. Figure ) • Cores at sztea P4 and PS
were also obtained that showed substantial orange—yellowish coloring,
particularly at PS. sample 020 (Tables 1 and 2). Th. lighter coloring
seems to be associated with the gas vents and some type of apparent
ozithzing process that penetrates th. sediment. Th. presence of both
anoxic and oxidized sediments is not inconsistent with th. character of
the lake water and the presenc. of the gas vents. At least some of the
mercury contained within the sediment may be originating from the gas
phas, as suggested by the elevated mercury level (38 mg/kg) in sample 20.
sit, P5.
Three duplicate 60—cm cores have bean retained by Columbia
Geoscience, as originally retrieved at sites P2, P3, and P4, as well as
submerged gas samples from a ma or gas vent (Figure 18). These may be
available for detailed study and analysis at a later date, such work is
outside the scop. of the present investigation.
DISCUSSWN
Hermn Lake Water
Chemistry data on Berman lake, the geothermal springs and wells, and
lake bottom sediments, have been tabulated in Tables 1 and 2, along with
several calculated ion ratios. Both Tables include all analyses of which
the writers are awsre for th. period 1937 to 1987, and many of the
referenced analyses may contain aupplementry data not reported here. The
logic of each Table layout is as follows: samples 1u12 (Herman lake
water) samples 13—22 (cores and a surface sediment sample near the
lake), samples 23—26 (ground—water sample. from wells), samples 27-28
(ponded spring water in a vent area)i and samples 29—30 (geothermal
springs now submsgqed by Berman lake).
One of th. accepted methods of examining a contaminated site is to
—23—
-------
Heraa lake is less than one million cubic meters. The proposal rsqv r,s
a total of from 495,000 to 540,000 cubic meters of mercury_rich
sedimentation in the bottom of Clear Lake since 1957 and a total of from
1,335,000 t: .,440,000 Cubic meters sines 1947. These figures represents
volumes of 1 S0 ft. by 73 ft. by 73 ft. for a ainim of mercury—rich
sedimentation sines 1957 and 3,280 ft. by 120 ft. by 120 ft. fog a
minimum since 1947. Extending the area out to include both U.S.G.S.
cor.s as the Board’s above—mentionad 1986 doc ent proposes, covering a
area of 1.5 ha by 3.5 ha lake—bottom area, the required vol . of
mercury—rich sedimentation from the Sulphur Bank area would be equal to
4.200.000 cubic meters, or 3,280 ft. by 385 ft. by 385 ft.
Based on the bathymetric lake voli e of about 900,000 cubic meters
(figure 4), and adding a rough estimate of an additional 50% to
represent excavated area above the current Herman lake water level, the
total excavation volume is unlikely to exceed 1,400,000 cubic meters for
the 125 years of the mine’s history. Xf one were to assune that the
sedimentary cores from Clear Lake were 50% water, the solid portion would
still equal 2,100,000 cubic meters of mercury rjeh sediments to be
derived from the Sulphur lank area to satisfy the above 1.986 document.
All of this is further compounded by the fact that the bulk of the
tailings piles are still present to the south, west, and north of the
mine excavations. The above volume calculations suggest that it would be
Physically impossibl, to attribute the mercury—rich sedimentary mass in
the up r an c of even a small portion of the Oak Arm to erosrun from
mining activities.
St1 ! ary
Many scientific investigations have been undertaken in the north-
eastern portion of Clear Lake, including the Sulphur Bank area. Most have
been undertaken by the U.S. Geological Survey or the California Bureau of
Mines. More recently the California Regional Water Quality Control Board
has also contributed to the body of data available for the area.
Currently the Bradley Mining Co. is funding this study of Herman Lake in
compliance with the California Toxic Pit Classification Act. The data
from these studies show that sediments in the Oak Arm of Clear Lake and
in Herman lake contain mercury. The data show that the ed{ments in Clear
Lake contain much more mercury than the sediments in Herman Lake. High
mercury values have been present in the sediments of Clear Lake for
thousands of years. The data show that mercury is not leaching into the
water of Herman lake from the sediments or adjacent reck. The data show
that mercury—bearing geothermal water and gas has been and is currently
discharging into Clear Like and Herman lake. Volume calculations show
that erosion from the Sulphur lank Mine cannot account for the
near-surfac , ercury-rich sediments in the Oak Arm of Clear Lake.
The water in Herman lake is acting to impound mercury which is
entering it either through discharging geothermal fluid or through
—40—
-------
erosion. The physical and chemical conditions of the lake act as a
atural treatment process which appears to efficiently restrict the
solubility of mercurY. This process acts to confine mercury to the floor
of the lake. As long *j the current pnysical and chemical conditions of
the Herman lake are preserved, t .s natural treatment proc. .. will
likely continue to impound the mercury.
CLOSURt OPTIONS
Th. options available for changing the toxic mercury deposition
from the geothermal discharge in both Clear Lake and the Herman lake are
limited. at. best. Unfortunately man cannot always control many ongoing
geologic forces of nature. Long—lived high temperature geothermal
systems, like earthquakes, fall into this catagory. Technology does not
exist today to stop an active geothermal system. Th. deposition point for
much of the mercury entering the mine, however. has likely been lowered
due to past mining activities. Prior to mining, the bulk of both sulfur
and mercury were being deposited at and very near the topographic
surface. Mining has lowered th. abrupt thermal and chemical gradients
fron the topographic surface to in and probably somewhat below the bottom
of the excavated area. except for the small area of intense discharging
on th. northern edge of the excavation where White observed cinnabar.
pyrit. and sulfur being deposited (Sims and White, 1981) the bulk of
mercury deposition in the mine area is probably now occurring at and
below these abri.ipt thermal and chemical boundaries.
The current physical conditions of the mine excavations stimulate the
precipitation of mercury introduced from the upwelling geothermal fluids.
An attempt to neutralize the water would be an aggressive and never-
ending process as long as the geothermal system continues to discharge
sulfur gasses. The c on closure action for acid water in actual acid
wine drainage problems, neutralizing the water and/or filling in th. body
of water, would have an und.sirable effect on the mercury distribution at
Sulphur 8ank. Filling the mm. excavation would remove the mercury—
impounding effects. The abrupt thermal and chemical boundaries would
again be at the topographic surface. Nercury and sulfur would likely
again be deposited on the surface of the Clear lake shore line.
The most effective strategy for the toxic mercury conditions in the
Sulphur Eank area would appoar to be one of preserving the current
conditions, allowing the Herman lake to continue to act as a natural
treatment process for that portion of the geothermal fluids discharging
to the east of the Clear Lake shore line.
l x
-41-
-------
I
(M*1ytt Z..boratory D t.a S ssta)
MN £ TPCA A33 3, rr.
SULPHUR MIOC MII .
tIAJ COUNT!. CALIFORNIA
for the
BRA©LET MINING CO WMT
by
Coliabt& Geoset. .
ease E. T.gztsr
ALbrt?. N iM1
i s a ?
-------
December 3, 1987
Lab ID: 32139
Enseco
James Luzler
Columbia Geoscience
2 Gershwin Ct.
Lake Oswego, OR 97034
Dear Mr. Luzier:
Enclosed Is the report for the
Mine Project, Number TPCA-58M which
November 1987.
nineteen Samples for your Sulfur Bank
were received at Enseco-Cal Lab on 3
The report consists of the following Sections:
I
II
“I
IV
No problems
If you have
Sample Description
Analysis Request
Quality Control Report
Analysis Results
were encountered with the analysis of your samples.
any questions, please feel free to call.
Sincerely,
li corp ...i4
2 44 Induarial Boukmd
E SWULILt*U . Californ ia 9 69I
9W372.I3 ) Fat: 916/)72 lulq
d . c
c Lab Manager
-------
C.A.N. NETAU
California Title 22 (TItle 26) Protocol
ITIC (Total) Data Sheet
Client Name : Columbia Geoscience
Client ID : P2-2111’ Z3P
Lab ID : 32139-012 Enseco ID : NA
Matrix : Soil Sainoled : 01-Nov-87 Received : 03-Nov-87
Authorized : 03-Nov-87 f gar : 10-Nov-87 Analyzed : 11-Nov-87
Wilts Reporting Re U ated Analytical
Eui ].t LOt wt.l Limit T1 ’LC STJg Method
Arsenic 49 mg/kg 40 500 5.0 6010
Antimony ND mg/kg 40 500 15 6010
Barium 1300 mg/kg 10 10000 100 6010
Beryllium ND mg/kg 0.50 75 0.75 6010
Cadmium ND mg/kg 0.50 100 1.0 6010
ChromIum 15 mg/kg 1.0 2500 560 6010
Chromium-y l NA mg/kg 1.0 500 5.0 7196
Cobalt 5.6 mg/kg 3.0 8000 80 6010
Copper 16 mg/kg 3.0 2500 25 6010
Lead ND mg/kg 5.0 1000 5.0 6010
Mercury .o mg/kg 0.10 20 0.2 7471
Molybdenum ND mg/kg 10 3500 50 6010
Nickel 18 mg/kg 5.0 2000 20 6010
Selenium NO mg/kg 5.0 100 1.0 7740
Silver ND mg/kg 2.0 500 5.0 6010
Thallium ND mg/kg 50 700 7.0 6010
Vanadium 16 mg/kg 5.0 2400 24 6010
Zinc 34 mg/kg 2.0 5000 250 6010
ND—Not Detected
NA—Not Applicable
Reported by: BEY — Approved by: JR8 )
The co r letter Is an integral part of this report.
Rev 230787
-------
C.AJI. METALS
California Title 22 (Title 26) Protocol
TTLC (Total) Data Sheet
QJ. .L2 : Columbia Geoscience
C]ient ID: P2 -23NT2
Lab 10 : 32139-011 Enseco ID : NA
Soil Sampled : 01-Nov-87 Received : 03-Nov.87
Authpr zed : 03-Nov-87 f ggar : 10-Nov-87 Analyzed : 11-Nov-87
Units Reporting Reaulat$ Ililti Analytical
( Wet wt. ) Limit TTLC ST ç Method
Arsenic ND mg/kg 40 500 5.0 6010
Antimony mg/kg 40 500 15 6010
Barium 120 mg/kg 10 10000 100 6010
Beryllium ND mg/kg 0.50 75 0.75 6010
Cadmium ND mg/kg 0.50 100 1.0 6010
Chromium 17 mg/kg 1.0 2500 560 6010
Chromium-VI NA mg/kg 1.0 500 5.0 7196
Cobalt 3.1 mg/kg 3.0 8000 80 6010
Copper 19 mg/kg 3.0 2500 25 6010
Lead ND mg/kg 5.0 1000 5.0 6010
Mercury 21 mg/kg 0.10 20 0.2 7471
Molybdenum ND mg/kg 10 3500 350 6010
Nick’& 6.3 mg/kg 5.0 2000 20 6010
Selenium ND mg/kg 5.0 100 1.0 7740
Silver MD mg/kg 2.0 500 5.0 6010
Thallium ND mg/kg 50 700 7.0 6010
Vanadium 21 mg/kg 5.0 2400 24 6010
Zinc 24 mqJkg 2.0 5000 250 6010
NO—Not Detected
NA—Not Applicable
c Reported by: 8EV Approved by: JRB )
The cover letter is an Integral part of is report.
Rev 230787
-------
C.A.M. METALS
California Title 22 (Title 26) Protocol
TTLC (Total) Data Sheet
Client Name : Columbia Geosc 4 e’c
Client ID : P3 -flMfl (1.. ‘tz. C v i i . ’)
Lab ID : 32139.014 Enseco ID : NA
Matrix : Soil Samoled : 01-Nov-87 Received : 03-Nov-87
Authorized : 03-Nov-87 £ 3 g : 10-Nov-87 Analyzed : 11-Nov-87
Units Reporting R.qu at.d Limits Analytical
EtsiLl.t ( Wet wt.) Limit TTI.C STLC Method
Arsenic ND mg/kg 40 500 5.0 6010
Antimony ND mg/kg 40 500 15 6010
Barium 120 mg/kg 10 10000 100 6010
Beryllium ND mg/kg 0.50 75 0.75 6010
Cadmium ND mg/kg 0.50 100 1.0 6010
ChromIum 10 mg/kg 1.0 2500 560 6010
Chromium-Vt NA mg/kg 1.0 500 5.0 7196 .
Cobalt 4.0 mg/kg 3.0 8000 80 6010
Copper 9.0 mg/kg 3.0 2500 25 6010
Lead ND mg/kg 5.0 1000 5.0 6010
Mercury 18 mg/kg 0.10 20 0.2 7471
Molybdenum ND mg/kg 10 3500 350 6010
Nickel 12 5.0 2000 20 6010
Selenium ND mg/ku 5.0 100 1.0 7740
S;lver ND mg/kg 2.0 500 5.0 6010
Thallium ND mg/kg 50 700 7.0 6010
VanadIum 16 mg/kg 5.0 2400 24 6010
Zinc 20 mg/kg 2.0 5000 250 6010
ND-Not Detected
NA—Not Applicable
Reported by: 8EV Approved by: JRBk )
The cover letter is an Integral part of TIi’s report.
Rev 230187
-------
C.A.N. NETAU
California 11th 22 (Tithe 26) Protocol
TTL C (Total) Data Sheet
C)ient Name : Columbia Geoscience
Client ID : P3-27 ) 181
Lab jQ : 32139-013 Enseco ID : NA
) 1ttrfx : Soil Samoled : 01-Nov-87 03-Nov-87
Authorized : 03-Nov-87 !rggjtgg: 10-Nov-87 Analyzed : 11-Nov-87
Units Reporting Rgoula .d If i1t Analyticaj
Aiai i.t ( Wit wt) limit TTLC STLC N.tho4
Arsenic 140 mg/kg 40 500 5.0 6010
Antimony MD mg/kg 40 500 15 6010
Sirius 250 mg/kg 10 10000 100 6010
Beryllium ND mg/kg 0.50 75 0.75 6010
Cadmium NO mg/kg 0.50 100 1.0 6010
Chromium 26 mg/kg 1.0 2500 560 6010
Chromium-Vt NA mg/kg 1.0 500 5.0 7196
Cobalt ND mg/kg 3.0 8000 80 6010
Copper 16 mg/kg 3.0 2500 25 6010
Lead ND mg/kg 5.0 1000 5.0 6010
Mercury 23 mg/kg 0.10 20 0.2 7471
Molybdenum ND mg/kg 10 3500 350 6010
Nickel 6.3 mg/kg 5.0 2000 20 601.0
Selenium ND mg/kg 5.0 100 1.0 7740
Silver ND mg/kg 2.0 500 5.0 6010
Thallium ND mg/kg 50 700 7.0 6010
VanadIum 29 mg/kg 5.0 2400 24 6010
ZInc 12 mg/kg 2.0 5000 250 6010
ND-Not Detected
NA-Not Applicable
Reported by: 8EV Approved by: JRB )
The cover litter is an integral part of bit’s report.
Rev 230787
-------
C.A.N. NETAU
California 11th 22 (Title 26) Protocol
TTLC (Total) Data Sheet
Client Name : Columbia Geoscience
Client 10 : P4-2SMTC (r’(I Ii
Lab 10 : 32139-015 Enseco ID : NA
Matrix : Soil Samoled : 01-Nov-87 Received : 03-Nov.87
Authorized : 03-Nov-81 f g j. g: 10-Nov-87 Analyzed : 11-Nov-87
Units Reporting R euhatd Limits Analytical
k kt& ( Wit wt.) Limit TTLC STLC Method
Arsenic ND mg/kg 40 500 5.0 6010
Antimony ND mg/kg 40 500 15 6010
BarIum 100 mg/kg 10 10000 100 6010
Beryllium ND mg/kg 0.50 75 0.75 6010
Cadmium ND mg/kg 0.50 100 1.0 6010
Chromium 14 mg/kg 1.0 2500 560 6010
Chromium-VI NA mg/kg 1.0 500 5.0 7196
Cobalt ND mg/kg 3.0 8000 80 6010
Coppsr 11 mg/kg 3.0 2500 25 6010
Lead ND mg/kg 5.0 1000 5.0 6010
Mercu”v 19 mg/kg 0.10 20 0.2 7471
Molybdenum ND mg/kg 10 3500 350 6010
Nicks) 5.3 mg/kg 5.0 2000 20 6010
a len1um ND mg/kg 5.0 100 1.0 7740
Silver ND mg/kg 2.0 500 5.0 6010
Thallium ND mg/kg 50 700 7.0 6010
Vanadium 17 mg/kg 5.0 2400 24 6010
Zinc 14 mgJkg 2.0 5000 250 6010
ND-Not Detected
NA-Not Applicable
Reported by: 8EV Approved by:
The cover letter Is an integral part of This report.
Rev 230787
-------
C.A.N. METALS
California Title 22 (Ti tie 26) Protocol
T1LC (Total) Data Shut
Client Name : Columbia Geoscience
Client i : P4-25 C ‘1•: C. ,..)
LabjQ : 32139-016 £nseco ID : NA
Matrix : Soil Samo : 01-Nov.87 Rece1y : 03-Nov-87
Authorized : 03-Nov-87 £ gQjr : 10-Nov.87 Analyzed : 11-Nov.87
Units Reporting Analytical
jj] tWit wt.l Llmit _ TrJ 1 ç ST ç Method
Arsenic ND mg/kg 40 500 5.0 6010
Antimony MD mg/kg 40 500 15 6010
BarIum 110 mg/kg 10 10000 100 6010
Beryllium ND mg/kg 0.50 75 0.75 6010
Cadmium ND mg/kg o.so 100 1.0 6010
Chromium 16 mg/kg 1.0 2500 560 6010
Chromium.yI NA mg/kg i.o 500 5.0 7196
Cobalt 3.9 mg/kg 3.0 8000 80 6010
Copper 12 mg/kg 3.0 2500 25 6010
Lead 5.4 mg/kg 5.0 1000 5.0 6010
Mercury 44 mg/kg 0.10 20 0.2 7471
Molybdenum ND mg/kg 10 3500 350 6010
N lcke 11 mg/kg 5.0 2000 20 6010
Selenium ND mg/kg 5.0 100 1.0 7740
Silver mg/kg 2.0 500 5.0 6010
Thallium ND mg/kg 50 700 7.0 6010
Vanadium 21 mg/kg 5.0 2400 24 6010
ZInc 14 mg/kg 2.0 5000 250 6010
ND-Not Detected
NA-Not Applicable
Reported by: 8EV Approved by: JR I
The cever letter Is art integral part of this report.
Rev 230787
-------
C.A.M. METALS
California Title 22 (Title 26) Protocol
TTLC (Total) Data Sheet
Client Name : Columbia Geoscience
Client ID : P4-ZSMBC ‘I
Lab ID : 32139-017 En3eco ID : NA
Matrix : Soil Sainoled : 01-Nov-87 Received : 03-Nov-87
Authorized : 03-Nov-87 gj g: 10-Nov-87 Analyzed : 11-Nov-87
Units Reporting Regglat Limits Analytical
( Wet wt.l Limit TTLC STLC Method
Arsenic ND mg/kg 40 500 5.0 6010
Antimony ND mg/kg 40 500 15 6010
Barium 86 mg/kg 10 10000 100 6010
Beryllium ND mg/kg 0.50 75 0.75 6010
Cadmium NO mg/kg 0.50 100 1.0 6010
ChromIum 13 mg/kg 1.0 2500 560 6010
Chromlum-VI NA mg/kg 1.0 500 5.0 7196
Cobalt NO mg/kg 3.0 8000 80 6010
Copper 11 mg/kg 3.0 2500 25 6010
Lead 6.2 mg/kg 5.0 1000 5.0 6010
Mercury 46 mg/kg 0.10 20 0.2 7471
Molybdenum ND mg/kg 10 3500 350 6010
Nickel 6.9 mg/kg 5.0 O0 20 6010
Selenium ND mg/kg 5.0 100 1.0 7740
Silver ND mg/kg 2.0 500 5.0 6010
Thallium ND mg/kg 50 700 7.0 6010
VanadIum 21 mg/kg 5.0 2400 24 6010
ZInc 15 mg/kg 2.0 5000 250 6010
ND-Not Detected
NA—Not Applicable
Reported by: 8EV Approved by: JR )
The cover letter Is an Integral part of this report.
Rev 230781
-------
C.A.N. METALS
California iiti. 22 (TItle 26) Protocol
TTLC (Total) Data Sheet
Ctlent Name : Columbia Geoscience
dlieLntJQ : PS-5NTI $/3,2j 3 •
LabJQ : 32139-018 Enseco 10 : NA
Matrjj : Soil Samoled : 01-Nov.87 Received : 03-NOV.87
Authorized : 03-Nov-87 Prepared : 10-Nov-87 Analyzed : 11-Nov.87
Units Reporting Reaulated L1m1 Aflhlytj .l
k iil1 !Mttwt.) Limit TTL. STLC _ Netho (
Arsenic ND mg/kg 40 500 5.0 6010
Antimony ND mg/kg 40 500 15 6010
Barium 1600 mg/kg 10 10000 100 6010
Beryllium ND mg/kg 0.50 75 0.75 6010
Cadmium NO mg/kg 0.50 100 1.0 6010
Chromium 26 mg/kg 1.0 2500 560 6010
Chromium-yl NA mg/kg 1.0 500 5.0 7196
Cobalt 4.8 mg/kg 3.0 8000 80 6010
Copper 27 mg/kg 3.0 2500 25 6010
Lead 5.2 mg/kg 5.0 1000 5.0 6010
Mercury 38 mg/kg 0.10 20 0.2 7471
Molybdenum ND mg/kg 10 3500 350 6010
Nickel 13 mg/kg 5.0 2000 20 6010
Selenium ND mg/kg 5.0 100 1.0 7740
Silver ND mg/kg 2.0 500 5.0 6010
Thallium ND mg/kg 50 700 7.0 6010
VanadIum 14 mg/kg 5.0 2400 24 6010
ZInc 16 mg/kg 2.0 5000 250 6010
ND—Not Detected
NA—Not Applicable
Reported by: 8EV Approved by: JR8, ,i
The cover letter Is an Integral part of Nts report.
Rev 230787
-------
C.A.N. METALS
California 11th 22 (TItle 26) Protocol
TTLC (Total) Data Sheet
Client Mime : Columbia Geoscience
Client ID : P5-5MhZ (C..r€.2 ’) 113; ,
Lab ID : 32139-019 Enseco ID : HA
Matrix : Soil SamDled : 01-Nov-87 Received : 03-Nov-87
Authorized : 03-Nov-87 gj g: 10-Nov-87 Analyzed : 11-Nov-87
Units Reporting R.aula d L1mi i Analytical
f .tiz k iili filet wt.l Limit TTLC STLC Method
Arsenic ND mg/kg 40 500 5.0 6010
Antimony ND mg/kg 40 500 15 6010
BarIum 980 mg/kg 10 10000 100 6010
Beryllium ND mg/kg 0.50 75 0.75 6010
Cadmium ND mg/kg 0.50 lOG 1.0 6010
ChromIum 16 mg/kg 1.0 250C 560 6010
Chromium-VI NA mg/kg 1.0 500 5.0 7196
Cobalt 5.0 mg/kg 3.0 8000 80 6010
Copper 22 mg/kg 3.0 2500 25 6010
Lead 5.9 mg/kg 5.0 1000 5.0 6010
Mercury 19 mg/kg 0.10 20 0.2 7471
Molybdenum ND mg/kg 10 3500 350 6010
Nickel 11 mg/kg 5.0 2000 20 6010
Selenium ND mg/kg 5.0 100 1.0 1740
Sliver ND mg/kg 2.0 500 5.0 6010
Thallium NO mg/kg 50 700 7.0 6010
Vanadium 9.3 mg/kg 5.0 2400 24 6010
Zinc 24 mg/kg 2.0 5000 250 6010
ND—Not Detected
HA—Not Applicable
Reported by: BEY Approved by: JRB . j
The cover letter Is an integral part of tMs report.
Rev 230787
-------
C.A.N. METALS
California TItle 22 (Title 26) Protocol
STIC (Leachable) Data Sheet
Citrate Buffer Leachat.
Client Name : Columbia Geoscience
Client ID : P2-Z5N2.3f’
Lab jQ : 32139-012 Enseco ID : NA
Matrix : Leachate Simoled : 01-Nov-87 Received : 03-Nov.87
Authorized : 03-Nov-87 18-Nov-87 Analyzed : 20-Nov-87
Reporting Reoulazed L1 It Analytical
RHMLt Un1t Limit TTJ STLC Method
Arsenic ND mg/I 1.0 500 5.0 200.7
Antimony ND mg/I 1.0 500 15 200.7
Barium 0.61 mg/I 0.50 10000 100 200.7
Beryllium ND mg/I 0.050 75 0.75 200.7
Cadmium ND mg/I 0.10 100 1.0 200.7
ChromIum 0.26 mg/I 0.10 2500 560 200.7 ._
Chromlum-VI NA mg/I 0.10 500 5.0 7196
Cobalt o.ig mg/I 0.10 8000 80 200.7
Copper 0.40 mg/I 0.10 2500 25 200.7
Lead ND mg/I 1.0 1000 5.0 200.7
Mercury ND mg/I 0.010 20 0.2 245.2
Molybdenum ND mg/I 1.3 3500 350 200.7
Nickel 0.78 mg/I 1.0 2000 20 200.7
Selenium ND mg/I 0.50 100 1.0 200.7
Silver ND mg/I 0.50 500 5.0 200.7
Thallium ND mg/I 1.0 700 7.0 200.7
Vanadium ND mg/I 0.50 2400 24 200.7
Zinc 1.4 mg/I 0.10 5000 250 200.7
ND.Not Detected
NANot Applicable
Reported by: 8EV Approved by: JRB )
The cover letter is an integral part of this report.
Rev 230787
-------
C.A.M. NETAU
California Title 22 (Title 26) Protocol
STIC (Leachable) Data Sheet
Citrate Buffer Leachat.
Client Name : Columbia Geoscience
Ctlent ID : P2 .23MT2
Lab 10 : 32139-011 Enseco TO : NA
Matrix : Leachate Sampled : 01-Nov47 Received : 03-Nov-87
Authorized : 03-Nov-87 frg2j : 18-Nov.87 Analyzed : 20-Nov-87
Reporting Reguipted Limiti Analyticil
Units LI mit TTLC S1 Method
Arsenic NA mg/I 1.0 500 5.0 200.7
Antimony NA mg/I 1.0 500 15 200.7
Barium NA mg/I 0.50 10000 100 200.7
Beryllium NA mg/I 0.050 75 0.75 200.7
Cadmium NA mg/I 0.10 100 1.0 200.7
Chromium NA mg/I 0.10 2500 560 200.7
Chromium-VT NA mg/I 0.10 500 5.0 7196
Cobalt NA mg/I 0.10 8000 80 200.7
Copper NA mg/I 0.10 2500 25 200.7
Lead NA mg/I 1.0 1000 5.0 200.7
Mercury 0.049 mg/I 0.010 20 0.2 245.2
Molybdenum NA mg/I 1.0 3500 350 200.7
Nickel NA mg/I 1.0 2000 20 200.7
Selenium NA mg/I 0.50 100 1.0 200.7
Silver NA mg/I 0.50 500 5.0 200.7
Thallium NA mg/I 1.0 700 7.0 200.7
Vanadium NA mg/I 0.50 2400 24 200.7
Zinc NA moj l 0.10 5000 250 200.7
ND.Not Detected
NA.Not Applicable
Reported by: BEY Approved by: JR8 j
- The cover letter is an Integral part of flis report.
Rev 230787
-------
C.A.N. NETAU
California 11th 22 (TItle 26) Protocol
STLC (Leachable) oats Sheet
Citrate Buffer Leachate
Client Na ’s . Columbia Geoscience
Client ID : P3-27MTI (T., ‘ s. C..ra)
Lab ID : 32139-014 Enseco ID : NA
Matrix : Leachat. Samoled : 01-Nov-87 Received : 03-Nov.87
Authorized : 03-Nov-87 .E ggj g: 18-Nov-87 Analyzed : 20-Nov-87
Reporting Reeulat L1.iti Analytical
IJiLLt Unita Limit TTLC STLC j 4
Arsenic NA mg/I 1.0 500 5.0 200.7
Antimony NA mg/I 1.0 500 15 200.7
Barium NA mg/I 0.50 10000 100 200.7
Beryllium NA rig/I 0.050 75 0.75 200.7
Cadmium NA mg/I 0.10 100 1.0 200.7
Chromium NA mg/I 0.10 2500 560 200.7 s..
Chromlum-VI NA mg/I 0.10 500 5.0 7196
Cobalt NA mg/I 0.10 8000 80 200.7
Copper NA mg/I 0.10 2500 25 200.7
Lead NA mg/I 1.0 1000 5.0 200.7
Mercury 0.019 mg/I 0.010 20 0.2 245.2
Molybr NA mg/I 1.0 3500 350 200.7
Nickel NA mg/ I. 1.0 2000 20 200.7
Selenium NA mg/I 0.50 100 1.0 200.7
Silver NA mg/I 0.50 500 5.0 200.7
Thallium NA moJL 1.0 700 7.0 200.7
Vanadium NA mg/I 0.50 2400 24 200.7
Zinc NA mg/I 0.10 5000 250 200.7
ND.Not Detected
NA.Not Applicable
4 Reported by: 8EV Approved by: JR j
th.’
Th. cover letter Is an Integral part of tills report.
Rev 230781
-------
C.A.N. METALS
California Title 22 (TItle 26) Protocol
STIC (Lea habl.) Data Sheet
Citrate Buffer Leachite
Client Name : Columbia Geoscience
C i lent ID : P3-Z7MB1 (3.’k’. - ‘li.. C.c.i 1 ,’)
Lab ID : 32139-013 Enseco ID : NA
Mttr1 : Leachate Samoled : 01-Nov.87 Received : 03-Nov-87
Authorized : 03-Nov-87 fr.egj g: 18•Nov .87 Analyzed : 20-Nov.87
Reporting Reculated Li ii t Analytical
Eui 1.t Units L1mlt TTLC S1 Method
Arsenic NA mg/I 1.0 500 5.0 200.7
Antimony NA mg/I 1.0 500 15 200.7
Barium NA mg/I 0.50 10000 100 200.7
Beryllium NA mg/I 0.050 75 0.75 200.7
Cadmium NA mg/I 0.10 100 1.0 200.7
Chromium NA mg/L 0.10 2500 560 200.7
Chromlum-VI NA mg/I 0.10 500 5.0 7196
Cobalt NA mg/I 0.10 8000 80 200.7
Copper NA mg/I 0.10 2500 25 200.7
Lead NA mg/I 1.0 1000 5.0 200.7
Mercury 0.035 mg/I 0.010 20 0.2 245.2
Molybdenum NA /L 1.0 3500 350 200.7
Nickel NA mg/I 1.0 2000 20 200.7
Selenium NA mg/I 0.50 100 1.0 200.7
Silver NA mg/I 0.50 500 5.0 200.7
Thallium NA mg/I 1.0 700 7.0 200.7
Vanadium NA ma lI 0.50 2400 24 200.7
Zinc NA mg/I 0.10 5000 250 200.7
ND—Not Detected
NA-Not Applicable
Reported by: BEY Approved by: JR9 )
The cover letter Is an Integral part of this report.
Rev 230187
-------
C.A.N. NETALS
California Title 22 (Title 26) Protocol
STLC (Leachable) Data Sheet
Citrate Buffer Leachate
Client Name : Columbia Geosc1snc
Client ID : P4.2SMTC (..t., 13
Lab jQ : 32139-015 Enseco ID : NA
Matrix : Leachate SamDled : 01-Nov-87 Received : 03-Nov-87
Authorized : 03-Nov-87 £.gjrgg: 18-Nov-87 Analyzed : 20-Nov-87
Reporting Re2ulat.d Ll,itJ Analytical
Eu 1.t Unita Limit TTLC STLC Method
Arsenic NA mg/I 1.0 500 5.0 200.7
Antimony NA mg/I 1.0 500 15 200.7
Barium NA mg/L 0.50 10000 100 200.7
Beryllium NA mg/I 0.050 75 0.75 200.7
Cadmium NA mg/I 0.10 100 1.0 200.7
Chromium NA mg/I 0.10 2500 560 200.7 .
Chromlum-VI NA mg/ I. 0.10 500 5.0 7196
Cobalt NA mg/L 0.10 8000 80 200.7
Copper NA mg/I 0.10 2500 25 200.7
Lead NA mg/I 1.0 1000 5.0 200.7
Mercury NO mg/I 0.010 20 0.2 245.2
Molybdenum NA mg/I 1.0 3500 350 200.7
Nickel NA mg/I 1.0 2000 20 200.7
Selenium NA mg/I 0.50 100 1.0 200.7
Silver NA mg/I 0.50 500 5.0 200.7
Thallium NA mg/I 1.0 700 7.0 200.7
Vanadium NA mg/I 0.50 2400 24 200.7
Zinc NA mg/I 0.10 5000 250 200.7
ND—Hot Detected
NA-Not Applicable
Reported by: BEY Approved by: JR8 1
The-cover letter is an integral part of 1 s report.
Rev 230787
-------
C.A.N. METALS
California iiti. 22 (Iitle 26) Protocol
STIC (Leachable) Data Sheet
Citrate Buffer L.achate
Columbia Geoscience
Client ID : P4-25#IC (t & I ( ‘3
1.ab 10 : 32139.016 Enseeo ID : NA
Matrix : Leachate Samoled : 01-Nov.87 Received : 03-Nov-87
Authorized : 03-Nov.87 jz g: 18-Nov-87 Analyzed : 20-Nov-87
Reporting Regu &t Lipits Analytical
fiuiil.t Unite LImit TTLC ST
Arsenic NA mg/I 1.0 500 5.0 200.7
Antimony NA mg/I 1.0 500 15 200.7
Barium NA mg/I 0.50 10000 100 200.7
Beryllium NA mg/i 0.050 75 0.75 200.7
Cadmium NA mg/I 0.10 100 1.0 200.7
Chromium NA mg/i 0.10 2500 560 200.7
Chrom lum.yI NA mg/I 0.10 500 5.0 7196
Cobalt NA mg/I 0.10 8000 80 200.7
Copper NA mg/i 0.10 2500 25 200.7
Lead NA mg/i 1.0 1000 5.0 200.7
Mercury ND mg/i 0.010 20 0.2 245.2
Molybdenum NA mg/ I. 1.0 3500 350 200.7
Nfek.1 NA ma l I. 1.0 2000 20 200.7
Selenium NA mg/i 0.50 100 1.0 200.7
Silver NA mg/i 0.50 500 5.0 200.7
Thallium NA mg/I. 1.0 700 7.0 200.7
Vanadium NA mg/i 0.50 2400 24 200.7
Zinc NA mg/i 0.10 5000 250 200.7
ND—Not Detected
NA-Not Applicable
Reported by: BEY Approved by: JR ,,)
The covs letter is an Integral part of this report.
Rev 230787
-------
C.A.M. METALS
California Title 22 (Title 26) Protocol
STLC (Leachable) Data Sheet
Citrate Buffer Leichat.
Client Name : Columbia Geoscience
Client ID : P4-ZSMBC ‘Ii
Lab ID : 32139-017 Enseco ID : NA
Matrix : Leachate Sainoled : 01-Nov-87 Received : 03-Nov.87
Authorized : 03-Nov-87 frgggi g: 18-Nov-87 Analyzed : 20-Nov-87
Reporting Reculatpd L1m1 1 Analytf &l
g jg 1tt Limit TTLC STLC Method
Arsenic NA mg/I 1.0 500 5.0 200.7
Antimony NA mg/I 1.0 500 15 200.7
Barium NA mg/I 0.50 10000 100 200.7
Beryllium NA mg/I 0.050 75 0.75 200.7
Cadmium NA mg/i 0.10 100 1.0 200.7
Chromium NA mg/I 0.10 2500 560 200.7
Chromlum-VI NA mg/I 0.10 500 5.0 7196
Cobalt NA mg/I 0.10 8000 80 200.7
Copper NA mg/I 0.10 2500 25 200.7
Lead NA mg/I 1.0 1000 5.0 200.7
Mercury ND mg/i 0.010 20 0.2 245.2
Molybdenum NA “ /I 1.0 3500 350 200.7
Nickel NA mg/I 1.0 2000 20 200.7
Selenium NA mg/I 0.50 100 1.0 200.7
Silver NA moJI 0.50 500 5.0 200.7
Thallium NA mg/I 1.0 700 7.0 200.7
Vanadium NA moJi 0.50 2400 24 200.7
Zinc NA mg/I 0.10 5000 250 200.7
ND-Not Detected
NA-Not Applicable
Reported by: 8EV Approved by: JR8 )
7 -
The cover letter is an Integral part of t Is report.
Rev 230187
-------
C.A.N. NETAU —
California Title 22 (Title 26) ProtKol
STLC (Leachable) Data Sheet
Citrate Buffer Leachat.
Client Name : Columbia Geoscience
Client ID : P5-SKTI
Lab 10 : 32139-018 Enseco IP : NA
Matrix : Leachate Samol.d : 01-Nov-87 Bg ij : 03-Nov-87
Authorized : 03-Nov-87 18-Nov-87 Analyzed : 20-Nov-87
Reporting Raoulat.d Liulti Analytical
Eui Lt Units Limit TTLC STjg PIethod
Arsenic ND mg/I 1.0 500 5.0 200.7
Antimony ND mg/I 1.0 500 15 200.7
Barium 1.2 mg/I 0.50 10000 100 200.7
Beryllium ND mg/P. 0.050 75 0.75 200.7
Cadmium ND mg/I 0.10 100 1.0 200.7
Chromium 0.45 mg/I 0.10 2500 560 200.7
Chromium-VI NA mg/I 0.10 500 5.0 7196
Cobalt 0.16 mg/I 0.10 8000 80 200.7
Copper 0.93 mg/I 0.10 2500 25 200.7
Lead ND mg/I 1.0 1000 5.0 200.7
Mercury NO mg/I 0.010 20 0.2 24 .5.2
Molybdenum 0.26 mg/I 1.0 S oO 350 200.7
Nickel ND mg/i 1.0 2000 20 200.7
Selenium ND mg/I 0.50 100 1.0 200.7
Silver ND mg/ I. 0.50 500 5.0 200.7
Thallium ND mg/I 1.0 700 7.0 200.7
VanadiwD ND mg/I 0.50 2400 24 200.7
Zinc 0.11 mg/I 0.10 5000 250 200.7
ND—Not Detected
NA—Not Applicable
Reported by: BEV Approved by: JRB /
- The coverietter is an Integral part of this report.
Rev 230787
-------
C.A.N. NETAU
California Title 22 (TItle 26) Protocol
STIC (Leachable) Data Sheet
Citrate Buffer Leachate
Client Name : Columbia Geoscience
( Ilent ID : P5 .5MT2 I1L2.
lab IQ : 32139.019 Enseco ID : NA
Mitrj : leachate Samoled : 01-Nov.87 Received : 03-Nov-el
Authorized : 03-Nov-87 .! jr g: 18-Nov-87 Analyzed : 20-Nov.87
Reporting Regulated haiti Analytical
f ir Rui Lt Units Limit TTLC STLC Method
Arsenic NA mg/I 1.0 500 5.0 200.7
Antimony NA mg/I .0 500 15 200.7
Barium NA mg/I 0.50 10000 100 200.7
Beryllium NA mg/I 0.050 15 0.75 200.7
Cadmium NA mg/I 0.10 100 1.0 200.7
Chromium NA mg/I 0.10 2500 560 200.7
Chromlum-VI NA mg/I 0.10 500 5.0 7196
Cobalt NA mg/I 0.10 8000 80 200.7
Copper NA mg/I 0.10 2500 25 200.7
Lead NA mg/I 1.0 1000 5.0 200.7
Mercury ND mg/I 0.010 20 0.2 245.2
Molybdenum NA mg/I 1.0 3500 350 200.7
Nickel NA mg/I 1.0 2000 20 200.7
Selenium NA mg/I 0.50 100 1.0 200.7
Silver NA mg/I 0.50 500 5.0 200.7
Thallium NA mg/I 1.0 700 7.0 200.7
Vanadium NA mg/I 0.50 2400 24 200.7
Zinc NA mg/I 0.10 5000 250 200.7
ND-Not Detected
NA-Not Applicable
Reported by: 8EV Approved by: JR )
The ëäver letter Is an integral part of this report.
Rev 230787
-------
4
Mining Waste NPL Site Summary Report
Tar Creek
Ottawa County, Oklahoma and Cherokee County, Kansas
U.S. Environmental Protection Agency
Office of Solid Waste
June 21, 1991
FINAL DRAFT
Prepared by:
Science Applications International Corporation
Environmental and Health Sciences Group
7600-A Leesburg Pike
Falls Church, Virginia 22043
-------
‘I
DISCLAIMER AND ACKNOWLEDGEMENTS
The mention of company or product names is not to be considered an
endorsement by the U.S. Government or by the U.S. Environmental
Protection Agency (EPA). This document was prepared by Science
Applications International Corporation (SAIC) in partial fulfillment of
EPA Contract Number 68-WO-0025, Work Assignment No. 20. A
previous draft of this report was reviewed by Noel Bennett of EPA
Region VI [ (214) 655-6715], the Remedial Project Manager for the
site, whose comments have been incorporated into the report.
-------
Mining Waste NPL Site Summary Report
TAR CREEK
OTI’AWA COUNTY, OKLAHOMA AND CHEROKEE COUNTY, KANSAS
INTRODUCTION
The Site Summary Report for the Tar Creek site is one of a series of reports on mining sites on the
National Priorities List (NPL). The reports have been prepared to support EPA’s mining program
activities. In general, these reports summarize types of environmental damages and associated mming
waste management practices at sites on (or proposed for) the NPL as of February 11, 1991(56
Federal Register 5598). This summary report is based on information obtained from EPA files and
reports and on a review of the summary by the EPA Region VI Remedial Project Manager for the
site, Noel Bennett.
SITE OVERVIEW
The Tar Creek site, a lead/zinc mining site, covers approximately 40 square miles across the border
of Ottawa County, Oklahoma, and Cherokee County, Kansas, in an area known as the Picher Mine
Field (see Figures 1 and 2). Lead and zinc were mined at the site from 1904 to the mid 1960’s.
After lead-zinc mining operation ceased in the 1960’s, the mines were flooded by inflows of surface
and ground water. The Boone limestone formation, where the mines are located, is rich in pyrite.
Excavation and subsequent flooding of the mine has resulted in the generation of acid mine water,
which has, in turn, mobilized the metals in the rock surrounding the mine workings. The acidic
nature of the mine water as well as the constituents of concern (zinc, lead, cadmium, and iron)
present problems at the site.
Approximately 21,000 people in five communities obtain their drinking water from the underlying
Roubidoux aquifer, which is approximately 1,100 feet from the surface. (Reference 1, pages 1 and
5.) According to the Remedial Project Manager, several municipalities in the mining region that use
the Roubidoux aquifer for drinking water have experienced water quality problems related to the
mines. For the most part, the water quality problems have been attributed to inadequate casings that
have allowed mine water to migrate into the Roubidoux wells. Acute surface-water problems in the
area exist. Although the surface water is not a source of drinking water, it is used for recreational
purposes, thus increasing the likelihood of dermal exposure to mine water through direct contact
(Reference 1, pages 4 and 5).
-------
Tar Creek
FIGURE 1. TAR CREEK DRAINAGE BASIN
‘a- “a
2
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[ PLANATION
- a —.
-
1 9
Mining Waste NPL Site Summary Report
FIGURE 2.
GENERALIZED LOCATION OF UNDERGROUND MINE WORKINGS
IN THE PICHER FIELD, OKLAHOMA AND KANSAS
A ’-
a
I . .’
I
3
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Tar Creek
In 1979, the Oklahoma Water Resources Board (OWRB) and the U.S. Geological Survey (USGS)
first investigated the site. Soon after the mine drainage began in late 1979, most of the biota in the
creek were killed, the banks and bottom of the creek turned red due to ferric hydroxide deposition,
and red stains appeared on bridge abutments and cliffs in the Grand River, downstream from its
confluence with Tar Creek (Reference 3, page 14). In October 1981, Tar Creek was added to the
NPL list (Reference 4, page 1).
A Record of Decision (ROD) describing the remedy at the site was signed in June 1984 by the EPA
Assistant Administrator for the Office of Solid Waste and Emergency Response. The States of
Oklahoma and Kansas agreed with the remedy, which included diversion of surface flows at three
sites and plugging of 66 Roubidoux wells followed by a ground-water monitoring plan to assess the
effectiveness of the surface diversion and well plugging. During the remedial action, an additional 17
wells were plugged. The ROD estimated the cost of future remedial actions, assuming a 30-year
period for site activities, to be $4 million in capital outlays and $5,000 per year in Operation and
Maintenance (O&M). Additional expenses were to be taken on by the State of Oklahoma, which
would conduct long-term ground-water monitoring (Reference 3, page 13). According to EPA,
remediation of the site was completed in 1986 and EPA is currently conducting monitoring.
OPERATING HISTORY
Lead-zinc ores were first discovered at the site in 1901, and the first mining output began in 1904. In
1914, the main body of ore was discovered, and mining activities increased substantially. From 1904
to the early 1930’s, mining was conducted by small operators on separate 4.0-acre tracts. In the
1930’s, centralized milling began, which led to the consolidation of mining operations. Large
capacity pumps were used during active mining to control ground-water inflow and flooding.
However, when large-scale mining activities ceased in the mid-1960’s, the pumps were removed from
the mines. By 1979, the majority of the underground mines were completely flooded. Acid mine
water began to discharge via abandoned or partially plugged mine shaft openings and boreholes
(Reference 1, pages 1 and 2).
SITE CHARACTERIZATION
The Tar Creek site encompasses several mines that open into the Boone formation, cherty limestone
averaging about 370 feet in thickness. Below the Boone formation are the Cotter dolomite and the
Jefferson City dolomite, each approximately 200 feet thick. Directly below the dolomite layers is the
Roubidoux formation, a 160-foot thick sequence of cherty dolomite with several sandy sequences (see
Figure 3). Surface features are characterized by numerous large tailing piles consisting primarily of
4
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Mining Waste NPL Site Summary Report
FIGURE 3. GENERALIZED GEOLOGIC SECTION SHOWING TILE LOCATION
OF THE WATER-FILLED MiNES
wtsT
LAST
100
00
100
S ALCV(L
—100
( I
5
-------
Tar Creek
limestone and chert (Reference 1, page 1 and Figure 3; Reference 1, Addendum 4, pages 1 and 2)
with collapsed structures such as mines and subsidence areas (Reference 1, page 1). An investigation
of the site identified two potential exposure pathways (surface water and ground water).
Surface Water
Tar Creek is the principal drainage system in the site. Tar Creek discharges to the Neosho and
Spring Rivers, and Grand Lake. Two springs were identified as the primary discharge sites for acid
mine water into the Tar Creek watershed. The first site is intermittent and discharges at an average
flow of 1.04 cubic feet per second (cfs) when flowing. The average pH at the point of discharge is
5.7, but can reach a minimum of 3.9. The concentration of the constituents of concern can vary at
the point of discharge, as shown in Table 1 (Reference 1, Table 2).
TABLE 1. SURFACE-WATER CONSTITUENT CONCENTRATIONS (j ig/I)
I Site One Site Two
Constituent
Mean
Maximum
Mean
Maximum
Iron
53,751
290,000
53,450
129,000
Zinc
38,644
141,000
87,250
137,000
Cadmium
56
260
43
69
Lead
171
1,920
27
47
The second site discharges year round at an average flow of 0.31 cfs. The average pH at the point of
discharge is 4.1, but can reach a minimum of 3.6. The variance in the concentration of the
constituents of concern is shown in Table 1.
Tar Creek can be best characterized as having high heavy metals concentrations, high hardness, and
low pH, as a result of low flow velocities and a low buffering capacity. Thus, the impact from acid
mine water is severe (Reference 1, page 3).
The Neosho and Spring Rivers, and Grand Lake, which receive water from Tar Creek, can be safely
used as a raw water source for public water supplies, and fish samples indicate that the fish are safe
for human consumption (Reference 1, page 5). Most of the heavy metals present in the acid mine
water precipitate out of the water and into the Tar Creek and Neosho River stream sediments. This
occurs primarily at the Tar Creek and Neosho River confluence, because the Neosho River has a flow
capacity approximately 500 times greater than Tar Creek and a much greater buffering capacity
(Reference 1, page 4). The Neosho River has received little impact from acid mine drainage into Tar
6
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Mining Waste NPL Site Summary Report
Creek other than aesthetic alteration at the Tar Creek confluence (Reference 1, page 6). Air impacts
were not evaluated.
Ground Water
There are two possible pathways for the migration of acid mine water from the Boone formation into
the Roubidoux formation according to the Remedial Project Manager. natural flow through the pores
and fractures of the intervening strata and flow through abandoned Roubidoux wells. Due to the low
permeabiities of the intervening strata (Cotter and Jefferson City dolomite formations), it is unlikely
that flow through the pores of intact material would occur. The hydraulic conductivities of the Cotter
and Jefferson City dolomite formations, measured from intact specimens, were 3.1 x i0 and 9.6 x
10 centimeters per second (cmlsec), respectively. It is also unlikely that fractures in the intervening
strata would be sufficiently interconnected to transmit flow from the Boone into the Roubidoux, a
distance of 300 to 400 feet. In addition, a self-plugging mechanism caused by chemical precipitation
was thought to impede natural flow (Reference 1, page 4).
A more likely mechanism for cross-contamination between the Boone and Roubidoux is abandoned
wells, which would provide direct access for mine water migration. To date, according to the
Remedial Project Manager, approximately 100 abandoned wells have been identified that extend from
the surface into the Roubidoux. USGS studies indicate a downward water flow at two of the
abandoned wells (Reference 1, page 5; Reference 5, pages 45 and 46).
ENVIRONMENTAL DAMAGES AND RISKS
Surface Water
At locations both above and below the acid mine water discharge points, chronic water quality criteria
for several heavy metals is exceeded. Heavy metal loadings increase downstream, while the pH
decreases, resulting in severe stress to the aquatic community of Tar Creek. Studies found no fish
and only a few bethnic macroinvertebrates surviving in Tar Creek. The greatest threat to human
health comes from dermal exposure to mine water from direct contact. Tar Creek is used for
recreational purposes, including swimming (Reference 2, page 2; Reference 1, pages 3 and 4).
Ground Water
The Roubidoux aquifer is the primary source of public drinking water in Ottawa County, according to
the Remedial Project Manager. It serves a population of 21,000 in five communities (Miami, Picher,
7
C’
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Tar Creek
Cardin, Quapaw, and Commerce) and a few rural water districts (Reference 2, page 5). Several
communities in Ottawa County have experienced water-quality problems related to the mines. The
contamination has been attributed to mine water entering the wells as a result of inadequate casings
(Reference 5, pages 45 and 46). Another possible pathway of contamination is migration of mine
water from the contaminated Boone formation through wells to the Roubidoux aquifer (Reference 1,
page 5).
REMEDIAL ACTIONS AND COSTS
The remedial action presented in the ROD consists of the following (Reference 1, pages 8 and 9).
• Roubidoux Wells - Well plugging at the site involves clearing the well holes of obstructions
and setting an acid-resistent cement plug from bottom to top. For the 66 abandoned
Roubidoux wells in Kansas and Oklahoma, the projected cost of construction varied from
$10,000 to $25,000 per well, depending upon the difficulty in clearing each well. The total
capital costs, including design, contingencies, and administrative costs, were estimated at
$1,951,900 with no associated O&M costs (Reference 1, page 8). According to EPA, the
actual cost of well plugging was $2,698,708. In addition to the 66 Roubidoux wells that were
identified for plugging at the time the ROD was prepared, an additional 17 wells were
identified for plugging during remedial actions. A total of 83 wells have been plugged to date.
• Surface Diversion - Construction of water diversion was proposed to prevent surface runoff
inflows into mine shafts, subsidence areas, and open boreholes. The action targeted three
major inflow areas (Muncie, Big John, and Admiralty) that combined, allowed approximately
75 percent of the yearly surface flows into the mine workings. Diversion work was directed
on two of the sites (Muncie and Big John), but the third site (Admiralty) would be diverted
only if changes in ground-water inflow made it necessary. Estimated costs for diversion at the
three sites is $2,000,000 in capital outlay and $5,000 in O&M per year for 30 years (Reference
1, page 13). According to EPA, the actual cost of the surface diversion program was
$1,570,605, with $8,000 in yearly O&M costs.
• Mpnitorin2- - A 2-year ground-water surveillance program was called for to determine if
diversion successfully stopped the discharge of mine water. The program was to begin after
the completion of the surface diversion efforts at Muncie and Big John to record ground-water
level changes. In particular, the surveillance program would monitor the impact of diversion
efforts at the Admiralty site to determine if diversion was needed there. In addition,
monitoring of the Roubidoux aquifer was directed to detect infiltration from the Boone aquifer
(Reference 1, Addendum 4, page 3). According to EPA Region VI, although no cost estimate
for the monitoring program was provided in the ROD, the cost of after-action monitoring was
$59,586.
8
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Mining Waste NPL Site Summary Report
The outlay to date for remediation of the Tar CreekfPicher Mine Field site is $3,269,313 in capital
expenditures and $59,586 for after-action monitoring, representing a total outlay of over $4.32
million plus $8,000 per year for O&M. The estimated cost of remediation was $3.95 million, with
O&M costs of $5,000 per year. The difference in the figures is attributable to a significantly higher
cost for well plugging, offset slightly by a moderately lower cost for the diversion program.
CURRENT S1 AThS
According to EPA Region VI, the well plugging and surface diversion activities have been completed.
Ground-water monitoring efforts will continue for several years. The State of Oklahoma continues to
assess the impact of the tailings piles at the site and to assess the impact of water degradation on
municipal water system wells
- 9
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Tar Creek
REFERENCES
1. Record of Decision for the Tar Creek Superfund Site, Oklahoma;, Lee M. Thomas, Assistant
Administrator, EPA Office of Solid Waste and Emergency Response; June 6, 1984.
2. Summary of Data Collected by Governor’s Tar Creek Task Force Regarding Ground-Water
Discharge From Abandoned Lead and Zinc Mines of Ottawa County, Oklahoma; Oklahoma
Water Resources Board; December 1979 to March 1981.
3. Tar Creek Field Investigation Task 1.1: Effects of Acid Mine Discharge on the Surface Water
Resources in the Tar Creek Area, Ottawa County, Oklahoma; Oklahoma Water Resources Board,
Water Quality Division; March 1983.
4. Hazard Ranking System Package, Tar Creek, Ottawa County, Oklahoma; EPA; August 2, 1983.
5. Geohydrology and Water Quality of the Roubidoux Aquifer, Northeastern Oklahoma, Open-file
Report 90-570; Scott C. Christenson, David L. Parehurst, and Roy W. Fairchild, U.S. Geological
Survey, Oklahoma City, Oklahoma; 1990.
10
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Mining Waste NPL Site Summary Report
BIBLIOGRAPHY
EPA. Hazard Ranking System Package, Tar Creek, Ottawa County, Oklahoma. August 2, 1983.
Hittman Associates, Inc. Surface and Ground Water Contaminated from Abandoned Lead-Zinc
Mines, Picher Mining District, Ottawa County, Oklahoma, Interim Report. July 1981.
Leet, Maria (SAIC). Telephone Communication Concerning the Tar Creek Site to Denis Hrebec,
Oklahoma State Industrial Waste Division. June 11, 1990.
Oklahoma Department of Health. Site Feasibility, Tar Creek Site, Ottawa County, Oklahoma, EPA
Grant No. CX 810192-0. January 1983.
Oklahoma Department of Health. Site Investigation, Tar Creek Site, Ottawa County, Oklahoma,
EPA Grant No. CX 810192-0. April 1983.
Oklahoma Water Resources Board. Governor’s Tar Creek Task Force: Data Summary of Surface
and Ground Water from Abandoned Lead and Zinc Mines of Ottawa County, Oklahoma.
December 1980 to July 1981.
Oklahoma Water Resources Board. Oklahoma Comprehensive Water Plan. April 1980.
Oklahoma Water Resources Board. Summary of Data Collected by Governor’s Tar Creek Task Force
Regarding Ground-Water Discharge From Abandoned Lead and Zinc Mines of Ottawa County,
Oklahoma. December 1979 to March 1981.
Oklahoma Water Resources Board, Water Quality Division. Tar Creek Feasibility Investigation.
1983. [ Ed. Note: individual task reports were submitted between August and December 1983.]
Oklahoma Water Resources Board, Water Quality Division. Tar Creek Field Investigation Task 1.1
Effects of Acid Mine Discharge on the Surface Water Resources in the Tar Creek Area, Ottawa
County, Oklahoma. March 1983.
Oklahoma Water Resources Board, Water Quality Division. Tar Creek Field Investigation Task 1.2:
Water Quality Characteristics of Seepage and Runoff at Two Tailings Piles in the Picher Field,
Ottawa County, Oklahoma. March 1983.
Oklahoma Water Resources Board, Water Quality Division. Tar Creek Field Investigation Task 1.3:
Water Quality Assessment of the Flooded Underground Lead and Zinc Mines of the Picher
Field in Ottawa County, Oklahoma. March 1983.
Oklahoma Water Resources Board, Water Quality Division. Tar Creek Field Investigation Task 1.3,
Subtask I.3.D: Estimation of the Quantity of Water in the FlOOded Underground Lead-Zinc
Mines of the Picher Field, Oklahoma and Kansas. March 1983.
11
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Tar Creek
Oklahoma Water Resources Board, Water Quality Division. Tar Creek Field Investigation Task 1.4:
Ground-Water Investigation in the Picher Field, Ottawa County, Oklahoma. March 1983.
Prepared for Oklahoma Water Resources Board by Hittman Associates, Inc Synopsis of Engineering
Perspectives for Contamination Occurring in the Picher Mining District, Contract No. H-
D8034-OO1-1042 FR. January 1982.
Reed, W.W., S.L. Schoff, and C.C. Branson. Geological Survey Bulletin 72. Ground-Water
Resources of Ottawa County, Oklahoma. 1955.
Tar Creek Task Force Health Effects Subcommittee. An Environmental Health Evaluation of the Tar
Creek Area: Executive Summary. March 1983.
Tar Creek Technical Subcommittee. Tar Creek Technical Subcommittee Superfund Reports:
Executive Summary, Draft. Undated.
Thomas, Lee M. (Assistant Administrator, EPA Office of Solid Waste and Emergency Response).
Record of Decision for the Tar Creek Superfund Site, Oklahoma. June 6, 1984.
U.S. Department of Agriculture. Soil Conservation Service, Engineering Division Computer
Program for Project Formulation, Technical Release Number 20. May 1982.
U.S. Department of Agriculture. Soil Conservation Service, Engineering Division. Technical
Release Number 61, WSPZ Computer Program. May 1976.
Wolfe, Mary (SAIC). Telephone Communication Concerning the Tar Creek Site to Denis Hrebec,
Oklahoma State Industrial Waste Division. July 11, 1990.
12
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0
Tar Creek Mining Waste NPL Site Summary Report
Reference 1
Excerpts From Record of Decision
for the Tar Creek Superfund Site, Oklahoma;
Lee M. Thomas, Assistant Administrator,
EPA Office of Solid Waste and Emergency Response;
June 6, 1984
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Rsvi aiaI R.spons.
Superfund
Record of Decision:
Tar Creek
Site,
Ag.nc
LOG
OK
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RECORD OF DECISION
REMEDIAL ALTERNATIVE SELECTION
SITE: Tar Creek/Picher Mine Field, Ottawa County, Oklahoma, and
Cherokee County, Kansas
DOCUMENTS REVIEWED
I am approving this action based on the followinc documents
describing the analyses of cost—effectiveness of remed al alter-
natives for the Tar Creek site:
— Tar Creek Site Investigation Report — Tar Creek Feasibility
Report Summary of Remedial Alternative Selection
DESCRIPTION OF SELECTED REMEDY
— Diversion and diking at two major inflow areas in Kansas. A
third area will also be diverted and diked if it becomes an
inflow site in Oklahoma.
— The plugging of 66 Roubidoux aquifer wells, 26 of which are
located in the Picher Mine Field area of Kansas.
— Implementation of a monitoring plan to assess effectiveness
of diversion in mitigating discharge of acid mine water to
the surface and well plugging in preventing contamination
of the Roubidoux aquifer.
DECLARATIONS
Consistent with the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA) and the National
Contingency Plan (40 CFR part 300) , I have determined that the
plugging of abandoned Roubidoux wells and diversion of surface
inflow-away from the mine workings provides adequate protection
of public health, welfare, and the environment. The States of
Oklahoma and Kansas have been consulted and agree with the
approved remedy.
In addition, I have determined the following conditions apply
to the enactment of the selected remedy.
1. The action being taken is appropriate when balanced
against the availability of Trust Fund monies for use at
other sites.
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—2—
2. The cost—effective remedy does comply with other
environmexital regulations.
3. Future remedial actions may be required if selected
alternatives do not adequately mitigate the risk to
human health.
4. Superfund assistance is necessary for Tar Creek because
of the limitations associated with other possible resources
for funding (see addendunt 5).
,e
Lee M. Thomas
Assistant Administrator
Office of
Solid Waste & Emergency
Response
/ Date
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SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
TAR CREEK
SIT! LQCAT ION AND DESCRIPTION
The Picher Field, located in Ottawa County, Oklahoma, and
Cherokee County, Kansas, is one of the lead—zinc subregions
which comprise the tn—state mining region of Oklahoma, Kansas,
and Missouri. The field encompasses six square miles, and was
one of the most productive lead—zinc mining districts in the
United States. Figure 1 shows the mine workings in the main part
of the Picher Field.
Surface features are characterized by n terous large
tailing piles consisting primarily of limestone and chert. There
are also several collapsed structures such as subsidence areas
and mine shafts that have caved in.
The Picher Field is situated on the west ridge of the Ozark
Plateau province. The Ozark Plateau is a broad, low Strubtured
dome laying mainly in southern Missouri and northern Arkansas.
However, the main part of the Picher Field is within the Central
Lowland province. This province is characterized by a nearly
flat, treeless prairie underlain by Pennsylvania shales.
The streams that traverse the mining field flow southward
to the Neosho River. Elm Creek, on the western edge of the
field, and Tar Creek and its main tributary, Lytle Creek, are the
principal streams. A short distance east of the mining field is
the Spring River, which is the major south—flowing tributary of
the Neosho.
The principal communities within the Picher Field are
Miami, Picher, Cardin, Quapaw, and Commerce. All these communities
receive their drinking water from the Roubidoux aquifer, which
/ is approximately 1,100 feet from the surface.
SITE HISTORY
Lead—zinc ores wer, first discovered in the Picher Field in
1901, with output of concentrates beginning in 1904. The main
portion of the ore body was discovered in 1914, leading to a
vast increaa in ore production. Early mining was characterized
by a multitude of small operators on 40 acre tracts, with each
operator conducting mining, drilling, and milling operations. In
the 1930’s centralized milling began, leading to the consolidation
of mining and milling operations.
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—2—
Large scale mining activities ended in the mid 1960’s and
ps were removed from the mines. By 1979, the majority of
the dergr0 mine workings were completely flooded and acid
mine water began to discharge via abandoned or partially plugged
mine shaft openings and boreholes.
Land ownership in Oklahoma was originally vested with the
Quapaw Indian tribe. The Quapaw Indians were given 150 sections
of land in southeastern Kansas and northeastern Oklahoma in 1833.
However, an allotment plan approved in 1893-94 divided the
reservation into 236 200—acre allotments and 231 40—acre allotments.
Today ownership can be classified as private, or Indian restricted.
ApproXimately 9,120 acres of Indian restricted lands are held by
Indian aliottees and (or) their heirs in the vicinity of the
Picher Field.
Since November 1979, the Tar Creek watershed has received
highly mineralized acid mine discharges from flooded underground
lead—zinc mines of the Picher Field in Ottawa County, Oklahoma.
The Oklahoma Water Resources Board (OWRB) in cooperation with
the Tar Creek Task Force investigated the problem initially in
1980 and 1981. Additional study of specific areas was deemed
necessary in order to fully assess the impact of acid mi.ne water
on the area’s surface and ground water resources.
In October 1981, Tar Creek was listed among the sites on the
National priorities List under the Comprehensive Environmental
Response, Compensation, and Liability Act of 1980 (CERCLA). A
Cooperative Agreement, with a grant award of $435,368 to conduct
Remedial Investigation/Feasibility Studies was signed between EPA
and the Oklahoma State Department of Health on June 16, 1982. An
Interagency Agreement was finalized with the Oklahoma Water
Resources Board for $173,000 to conduct monitoring and sampling.
Investigation work began in July 1982 and was completed in
March 1983. The final report was approved the month thereafter.
The Feasibility Study was initiated in May 1983 and completed in
December 1983. The major findings of the investigation and
feasibility reports are discussed in the section titled Current
Site Statu s.
CURRENT SIT! STATUS
As with many underground mines in the area, continual inflo .
of ground water during mining posed a probl.m. Inf lows were con-
trolled by th. instillation of large capacity pumps. However,
upon cessation of mining activities, drifts and shafts of the
abandoned workings began to flood. Pyrit.—rich wastes in the
Boone formation were being oxidized by exposure to the ozygen-r
atmospher. while mining was occurring. Upon flooding, these
oxidized suif ides rsadily dissolved into th. surrounding ground
water producing acid mine water. The acid water reacted with
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the surrounding rock causing many of the metals present to dissolve
resulting in s water with high concentrations of zinc, lead and
cadmiuut. These are pollutants and contaminants and are listed
hazardous substances under 101(14) of CERCL 1 A. Th concentratLon
of these three metals, as well as iron, greatly exceed dri.nk ng
water standards as shown in Table 1.
Discharge of these acid ground waters at the surface has
resulted in degradation of Tar Creek and could eventually affect
other major water resources of the area. Of potentially greater
importance is the impact of acid mine water on the underlying
Roubidoux aquifer. The contamination of the Rouba.doux on a
large scale would result in the loss of current municLpal water
supplies for much of the region.
The Tar Creek Investigation was developed to assess the
health and environmental impacts of acid mine drainage on
potential ground water and surface water receptors. Of foremost
concern are the impacts to the area’s drinking water sources:
Grand Lake and the Roubidoux aquifer.
The following is a separate discussion on each of the cri.t .cal
pathways for migration.
Surf ace Water Impacts -
Tar Creek is the principal drainage system in the Picher
Field. With its headwaters in Cherokee County, Kansas, Tar Creek
flows southerly through the field between Picher and Cardin,
passing Commerce and Miami on the east, to its confluence with
the Neosho River, one of two major rivers in northeastern Oklahoma.
Tar Creek is a small ephemeral stream characterized by standing
pools. Along with its major tributary Lytle Creek, Tar Creek
drains approximately 53 square miles of area.
The primary discharge points for acid mine water into the
Tar Creek watershed are sites 45 and 14 (Figure 2). Site 4s is
intermitent and discharges at an average flow of 1.04 cf s when
flowing. Site 14 discharges all year long at an average flow of
0.31 of s. Typical concentrations of heavy metals discharging
from the streams ar. shown in Table 2. Because of the low flow
velocities at most times of the year, and the low buffering
capacity of Tar Creek, the impact from acid mine water is severe.
ence Tar Creek is characterized as having high concentrations
f heavy metals, high hardness, and low pH. Tar Creek has had a
,H of 2.9 as far downstream as Miami.
As exhibited in Table 2, the chronic water quality criteria
r several heavy metals is exceeded for all parameters above
nd below the acid mine water discharge points. There is, however,
a significant increase in heavy metal loadings (and a decrease
I
‘1
Ec ’
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Table 2.
Statistical sus mary of Water quality data for mine
disàharge sites (1980—82).
Site
•
Mean
Maximum
Number
Concentration
Concentration
Water Quality
Criteria
pH (SO )
4
5.7
3.9
10
5.7
3.3
14b
4.1
3.6
20
5.4
2.9
22
6.5
4a
12,020
4
53,751
96,000
290,000
10
27,137
162,000
14b
53,450
20
8,853
129,000
52.000
22
1,278
2,890
4a
Zinc
27,398
(ug/L)
4
38,644
10
37,247
151,000
15b
87,250
20
21,333
22
7,582
14,200
320
47
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Table 2. (ContLnuation)
Site *
Nwnber
Mean
Concentration Concentration
Crir_
Acute
eria
ChronLc
4a
4
10
].4b
20
22
Cadn iu % (ug/L)
3.0
0.025
24.0 59
56.0 260
32.0 82
43.0 69
18.6 63
4.0 11
4a
4
13
14b
20
22
Lead (ug/L)
2.0 49
171.0 1,920
92.0 1,090
26.7 47
33.0 196
20.0 20
* site 4a is upstrsam of discharge point; 4 is a mine discharge
site; Sit. 10 is approximately 3 miles downstream from Site 4;
Sits 14 is 1/2 ails below discharge point 14; Site 20 is 10
miles below dischar;I point and near Miami; Site 22 is at the
tar Cre.k—NsOshO Rivsr confluence.
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—4—
downstream from the acid mine discharge points at site 4s
14 resulting in severe stress to the aquatic community of
and creek. Studies conducted by the Tar Creek Task Force
bCo flittee on Environmental Effects found no fish and only a
few benth C macroinverte ateS surviving in Tar Creek.
Tar creek is not used for a drinking water source. The
greatest threat to human health along Tar Creek comes from possible
dermal exposure to mine water from direct contact. Local residents
use Tar Creek for recreational purposes including swimming.
The remedial investigation showed that Tar Creek currently
has flO significant irr.pact on Grand Lake because when Tar Creek
waters flow into Grand Lake, mcst of the heavy metals prec oitate
out of the water and into the Tar Creek and Neosno River stream
sediments. The primary location where this phenonmenon occurs
is at the Tar Creek and Neosho River confluence. With the Neosho
River having flow capacities approximately 500 times greater
than that of Tar Creek plus much greater buffering capacity, the
acid mine water dilutes quickly and the heavy metals precipitate
out. Inspection of water quality data at site 22b and data
from heavy metal loadings in the sediments confirms these
predictions.
Ground Water Impacts
There are two possible pathways for migration of acid water
from the Boone Formation into the Roubidoux (Figure 3). These
pathways are: natural flow through intervening strata and flow
through abandoned Roubidoux wells. Therefore, the goal of the
ground water portion of the investigation was to assess the
potential for migration via these pathways.
To assess the potential for acid mine drainage to flow under
natural conditions from the Boone into the Roubidoux, hydraulic
conductivity studies were done on cores from the intervening rock
formations. The findings revealed very low permeabilities of
3.1 x 1o and 9.6 x i0 9 cm/sac, for the Cotter and Jefferson
City dolomites, respectively.
In addition to the low permeabilities, a self plugging
mechanism caused by chemical precipitation is thought to impede
natural flow. On the same cores in which permeability studies
were conducted, mine water was introduced at a mixture of 1:2 and
1:20 mine water to Roubidoux water. In the subsequent permeability
tests, there was a reduction in core permeabilities of 72% and
67% respectively.
Some potential exists for contamination of the Roubidoux by
natural flows if fractures are interconnected from th. Boone down
through the Cotter and Jefferson City formations and into the
Roubidoux. It is unlikely that any interconnections span the
entire 300—400 ft. distance between the Boone and the Roubidoux.
-
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— —
Mother mechanism for cross—contamination between the Boone
and Roubidoux is abandoned wells. These wells provide direct
access for mine water to migrate into the Roubidoux. The USGS
conducted studies on two of the abandoned wells and showed that
water was flowing downward. Sixty—Six wells have been identified
that extend from the surface into the drinking water aquifer. A
possibility exists that more abandoned wells could be discovered
in the future. If this occurs, additional funds would have to
•be requested in order to plug them.
Unlike the acute surface water problem, the Roubidoux aquifer
is still a safe drinking water supply. Five communities (Miami,
Picner, Cardin, Comrnerce and QuaDaw) and a few rural water distr .cts,
with a total population of approximately 21,COO, receive their
drinking water from the Roubidoux aquifer. Most of the historical
data on drinking water quality of the affected community wells
indicate no degradation to date. The exception is the city wells
serving Quapaw. At this location, two wells were abandoned
because of mine water influx. Contamination is attributed to
either casing failure or migration of mine water from nearby
abandoned wells.
Other Environmental and Public Health Findings :
• Water distributed by the public water supplies and rural
water districts of the Tar Creek area is safe to drink.
• The Neosho River, Spring River and Grand Lake can be
safely used as a raw water source for public water
supplies.
• The fish fillet samples indicate fish from the mouth of
Tar Creek, Neosho River, Spring River and Grand Lake are
safe for human consumption.
• No significant concentrations of toxic metals or radiation
were observed in the particulate air samples collected
at Pich.r.
• Effects on th. fish co unity diminish rapidly, once
waters enter the Neosho River.
• Metals found in the fish indicate that biomagnification
is not significant in the fish community of Grand Lake.
Although Tar Creek provides a concentrated source of
metals, the head waters of the Neosho and Spring Rivers
also contribute large quantities of metals.
• Sediments provide an effective long-term sink for metals
and should effectively remove them from most biological
processes.
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—6—
• The Neosho River has received little impact .. om acid
mine drainage into Tar Creek other than aesthetic
alter4tiw at the Tar Creek confluence.
• At current spring flows, all mine water will be displaced
in 60 to 100 years.
• There is an estimated 76,000 acre feet of heavy metal
laden mLne water .ri the flooded underground mines.
• Mine waters are be .ng introduced into the Roubido .ix v a
abandoned wells.
• Although sorne contam nati n of heavy metals re provided
by the tailings piles the overall quantity is nsign .f cant
compared to loading rates from the springs.
ENFORCEMENT
A meeting was held with the potentially responsible parties
on anuary 16, 1984, to determine willingness to participate in
design/construction activities. None of the companies provided
assurances that they would participate in funding cleanup’at
that time. The companies were asked to negotiate among themselves
and reply as to their intentions by February 16, 1984, and they
did not formally respond. The parties have been informed that
the Agency will proceed with the ROD and they will have 30 days
following its signature to agree on a cleanup.
ALTEP2 ATIVES EVALUATION
The objectives for cleanup at the Tar Creek site were to
mitigate the potential threat to public health and the environment
by preventing contamination of the Roubidoux and by minimizing
toxic releases damage to Tar Creek. Two of the seven alternatives
initially selected for evaluation addressed both cleanup ob ect ves
and would accelerate the improvement at ground water quality in
the Boone formation. Thes, remedial options were:
• In situ treatment of mine water
• Collection and treatment of mine water
Both alternatives were eliminated from detailed analysis
because they were excessively expensive. Long-term pumping and
treatm•nt of ground water from the Tar Creek area would be
expensive and imprecise. Present value capital and operation
and maintenance costs were estimated to approach $30 million.
This option is ineffective because long-term pumping would not
assure significantly less contaminated ground water.
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—8—
2. Plug 66 RoubidOux WeUs
The well plugging program would consist of clearing the well
holes of obstructions and setting an acid resistant ceme ”: plug
from bottom to top (Figure 4) in Sixty—Six abandoned Rou:.. oux
wells in Kansas and Oklahoma (see Figures 5 and 6 for locations).
It is projected that construction costs will vary from $10,000
to S25,000 per well depending upon the difficulty in clearing
each well. The total capital costs, including design, contirtgenc es,
and administrative costs, are $1,951,900 with no associated O&M
costs.
The well plugging program will not completely mitigate all
threats tO the Roubidoux aquifer. There are several ways that
the Boone may contaminate the Roubidoux (as ou:li ed in tne C:
water Impacts Section) including: fractures, unknown abandoned
wells and natural flow. There is also a slight potential that
some of the identified abandoned Roubidoux wells may be technically
difficult or impossible to plug. If additional abandoned
Roubidoux wells are located, add tional funds would be required
in order to plug them. Therefore, implementation of a monitoring
program is recommended to detect trends in water quality of the
RoubidOUx. The detailed plans for the Roubidoux monitoring
program are given in Addendum 4.
3. Surface Diversion
There are 600 mine shafts and collapse depressions within
the cstudy area each providing avenues for inflow of surface
water into the mines. Total inflow is estimated to be 5,000
acre—feet per year. Once water has entered the mines, it acidifies
and flows out of springs into Tar Creek further downstream.
Surface discharge is estimated to be 1,000 acre—feet per year.
The remainder of the inflow is believed to be removed from the
system via lateral ground water flow in the Boone. Inf low points
were ranked in th. feasibility study to determine those providing
significant inflow reduction and the cost effectiveness of
plugging or diverting water from these areas as shown in Table 3.
- The hydraulics of the mine system are such that water entering
the mines at sites —1 and K—2 in Kansas flow out of springs and
into Tar Creek downgradient in Oklahoma. Approximately 3,800
acre—feet p.r year flows into these sites. The main inflow
point is K—i (Muncie) which drains 4.52 sq. mi. and provides
2800 acre-feet of water to the mines in a year. The next priority
area is x—2 (Big John) which is responsible for 1,000 acre—feet
of the total surface water entering the mines each year.
Diversion work at K—i and K—2 will significantly reduce the
inflow and cause ground water levels to recede. If ground water
levels drop below the present static water level at site 0—3,
then it too will become an inflow point and may require diking
and diversion work.
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RECOMMENDED ALTERNATIVES
Section 300.58(j) of the National Cont ngency Plan states
that RThe appropriate extent of remedy shall be determined by
the lead agency’s selection of the remedial alternative which
the agency determines is cost—effective (i.e. tne lowest cost
alternative that is technologically feasible and reliable and
which effectively mitigates and minimizes damage to and provides
adequate protection of public health, welfare or the environment)”
Based upon investigation and feasibility studies, EPA Region VI
and the States of Oklahoma and Kansas agree that the well plugging,
and the diversion and dik ng programs meet the NC? criteria.
The diversion program will constitute rerouting surface
flows away from mine shafts, subsidence areas, and open boreholes.
Three major inflow areas allowing approximately 75% of the yearly
surface flows into the mine workings are designated for diversion
work. The Muncie and Big 3ohn diversion work will be implemented
at the completion of design. However, the Admiralty diversion
work will be delayed twelve to eighteen months to establish new
inflow and outflow patterns. The Admiralty will be constructed,
if required.
Because the diversion work may not completely stop all
surface discharge of acid mine water, a ground water monitoring
rrogram of the Boone aquifer will be conducted for two years to
allow time for the system to equilibrate and to determine the
effectiveness of the diversion work. If there continues to be
significant discharge, remedial measures would be evaluated to
determine if further action is appropriate.
There are many more inflow areas that were considered, but
each taken on a individual basis is insignificant compared to
the top three priority sites. Therefore, to do diversion work
at these sites would result in decreasing environmental protection
that cannot be justified by the increased costs. The capital
cost for diversion at the three sites is $2,000,000 with O&M
costs of $5,000 per year for 30 years.
The diver-sion work may not completely stop the surface
discharge of mine water. A surveillance program will be initiated
after construction to record ground water level changes. The
plan for this monitoring program along with th• water quality
monitoring program for the Roubidoux is given in Addendum 4.
Well plugging is the cost—effective remedy to protect the
ROubjdo x. This portion of the remedy is expected to cost
UJO0,000 and should assure that contaminated mine waters from
the Boone do not affect the Roubidoux. Provision of an alternative
source of water to the Town of Commerce is not required because
the ROubid ux is a saf• source of drinking water. The State
will undertake a long—term ground water monitoring program of
the R ubidoux to assure the safety of the Roubidoux.
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ADDENDUM 4
Tar Creek Site
Ottawa County, Oklahoma
Remedial Alternatives Analysis
TAR CREEK GROUND WATER MONZTORING PROGRAM
I. PURPOSE
T e u: ose of th :s t :
1. Review the Tar Creek Site Remedial Alternatives Ana1ys .s
itt areas discussing a post closure ground water level
monitoring plan.
2. Describe i tt more detail a post closure ground water
level monitoring plan.
II. INTRODUCTION
The Site Investigation report presented a descriptio of
the Tar Creek site hydrogeology. The following discussion only
refers to the Boone and Roubidoux hydrogeology.
The Boone Formation is a Mississippian age cherty limestone
averaging about 370 feet in thickness. Lead and zinc deposits
of the Picher Mining District are found in various members of
the Boone. Prior to initiation of large scale mine dewatering,
the Boone was probably the manor source of water for the local
residents.
To maintain unsaturated conditions in the mine workings,
large capacity suap pumps were used. Pumpage from the Boone
varied with time and depth of mining. During World War II an
estimated 14 mgd were discharged by the various mining operations.
As the demand for lead and zinc declined after the war, pumpage
declined to about 9 mgd as the lower grade ore present in deeper
workings wire abandoned (Reed, 1955). Pumping from the Boone
continued until the mid—]960’s when major mining ceased.
Water levels of the Boone recovered to their approximate
pre—mirti.ng level by 1980 and began discharging at the surface
in 1979. Recharge to the Boon. system comes not only from
natural infiltration, but also from direct surface water inflow
to shafts, bore holes and collapsed structures.
-C ’
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—2—
The Boone contains so1ut .on openinçs which enhance the
movement of g round water and produce large water yields from
wells intersecting these passageways. A well not enc3unter ng
any solutiort cavities or fractured zones might y eld only
moderate amounts of water. TrartSmissivity values as calculate
by Hittman AssocLates, ranges between 43,000 to 75,000 gpd/ft
for confined and urtcortfirted conditions respectively.
III. ROUBIDOUX FORMATION
The Rou idoux Formation is a 160 foot th ck sequence of
Ordovician a;e cherty doomite th several v ss e-ices.
This aqu.fer is the c a;or a:er prc:uce ror C: t,.
Depth to this aquifer is genera .ly between 03 to 1000 feet in
the miru.ng area. Reed (1955) reported that wells completed in
the Roubidoux flowed at the surface prior to 1919. The increased
water withdrawals by t e numerous mining and milling operations
caused a lowering of the potentiometric surface of the Roubid ux,
with pumping Lifts reaching more than 500 feet by 1947. water
level decline within the Roubidoux apparently has stabilized,
at least since 1975, based upon water level data obtained from
the city of Miami, Oklahoma. Seasonal water level fluctuations
can be observed; however, the potentiornetric surface of the
Roubi.doux appears to have remained about 320 feet above msl.
around Miami, Oklahoma, since 1975.
Away from the major pumping areas, the potentiometric
surface of the Roubidoux is higher. P. well completed in the
Roubidoux at the Eagle Picher Boron Plant had a reported water
elevation of approximately 490 feet above ms ].
D rection of ground water movement in the Roubidoux is not
well defined; however , it is inferred to be in a generally
wester1y direction.
1. Aquifer Parameters
Data concerning aquifer testing in the Roubidoux are
limited. Reed (1955) analyzed three pumping tests of Roubidoux
wells at the B.F. Goodrich plant near Miami, Oklahoma, and
determined an av.rag. tranamissivity valu• of approximately
39,000 gpd/ft and a storag. coefficient of 8 x 10 .
2. Water Quality
Ground water dsrivsd from Roubidoux wells generally has a
total dissolved solids (TDS) concentration of less than 500
milligrams per liter (mg/i). Water from the Roubidoux is
typically classified as a calcium—bicarbonate or a sodiumchloride
type, based upon the milli.quival.rtt concentration p.r liter of
-------
—3—
tr e major anions and cations. Dissolved metals are us..ially
reseflt Only in trace amounts; however, a well, at the Eagle Picher
Boron plant has reported high Concentrations of dissolved metals,
especially iron.
IV. Proposed Post Closure Ground Wate: Mcnitor g Plan
‘here are two separate c torirtg programs reCorru!tended for
implementatio’t. These are the Roubidoux water cuality monit rir ’ ;
program and the mine ground water level surveillance pian. The
following is an outline of ea:rt program.
A. Roi oux u fe: ‘:n.:cr:’.; ia
The following Roubidoux Aquifer Monitoring Plan is sug;este
as a possible measure to detect infiltration from the Boone
Aquifer.
The municipal wells listed below are suggested as possible
indicator locations for monitoring of the Roubidoux Aquifer:
Each well will be collected and analyzed twice each year,
once in October and once in April for the following parameters:
a) e) Total hardness
b) Iron f) Lead
c) Manganese g) Cadmium
d) Sulfate h) Specific Conductance
B. Mine Ground Water Level Monitoring Plan
A ground water level surveillance program is suggested to
determine success of diking and diversion work in preventing
surface flow of mine discharges. The plan will entail monitoring
the rates of spring discharge arid ground water levels in selected
nearby mines for two years after closure. Actual n asurements
of these parameters should be done at least four times a year
with the greatest number of observations being collected during
high ground water levels and/or after high precipitation events.
/
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“p
Tar Creek Mining Waste NPL Site Summary Report
Reference 2
Excerpts From Summary of Data CoHected by
Governor’s Tar Creek Task Force Regarding
Ground-Water Discharge From Abandoned Lead and Zinc Mines
of Ottawa County, Oklahoma; Oklahoma Water Resources Board;
December 1979 to March 1981
-------
TARCK.1 JOB X July 15, 1981 DRAFT
INTRODUCTION
In response to a complaint regarding historically poor water quality and
recent mine discharges into Tar Creek, Oklahoma Water Resources Board
personnel reconnoitered the Tar Creek basin in Ottawa County on February
5, 1980.1 Conclusions of this reconnaissance led to the following
recomeendations:
Further Investigation is necessary to determine:
(1) Mov.ment of water In the Boone Formation through the
mined area, and directions of flow and possible
consequences to Roubidoux Formation, and the impact of
these formations on rural domestic and stock wells,
stream contamination, and springs.
(2) Variations and trends of water quality In groundwater in
abandoned mines and groundwater levels.
(3) Future impact of mine discharge of the artesian spring on
Tar Creek.
On June 2, 1980, Governor George Nigh formed the Tar Creek Task Force
which is composed of 23 state and federal agencies, and local interest
groups (Appendix A). The interdiscipl inary nature of the Tar Creek Task
Force provided needed expertise in each of the problem areas identified
by OWRB reconnaissance, i.e., stree ater, groundwater, and mine water
quantity and quality, and biological reconnaissance and sampling and
allowed development of a work plan which •stabllshed a monitoring system
to satisfy the recomeendations cited In the OWRB Tar Creek
reconnaissance report (Appendix B). This report will sumarize the data
gathered on all elements of the work plan.
1 Adams, James C. 1980. Tar Creek Quality Reconnaissance Regarding
Groundwater Discharge From Abandoned Lead and Zinc Mines of Picher
Field, Ottawa County, Oklahoma. Oklahoma Water Resources Board,
Publication No. 100.
4
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TARCX1 JOB X July 15, 1981
MATERIALS AND METHODS
Stream sample sites, frequency, and analyses parameters are in
accordance with Phase I of the Task Force work plan. Sample sites were
located as shown in Figure 1. Narrative descriptions of each sample
site are given in Table 1.
Water samples were taken from each site sample and consisted of one-half
liter for chemical quality, iced to 4°C; one-half liter for filtered
metals using a 0.45 micron Mull pore filter system; and one-half liter
for total metals preserved both with nitric acid and iced to 4°C. Field
parameters were recorded at each site using a Model 4041 dIgital
Hydrolab. Sample analyses were performed by the Oklahoma State
Department of Health, Water Quality Laboratory (see Tables 2 and 3).
Bottom material sampling was discontinued because of substrate type.
The U.S. Geological Survey collected 24—hour monitoring data at SI tes 10
and 20 for pH, 0.0., specific conductance, and temperature, using a
mounted Hydrolab unit. Site 20 also contained a USGS manometer to
record flucuatlons in stream stage. Flow measurements at Sites 10 and
20 were performed by USGS personnel for development of a flow/stage
curve. Flows were measured with a py ny flow meter using a beaded
transect line and stopwatch.
Table 2 is a compilation of all data collected at stream sites from
December 27, 1979, to March 6, 1981. It is presented by site and by
dates for each par eter analyzed. Table 3 is a historical presentation
of the sims data organized In a format to compare various sites by date.
Groundwater sampling consisted of two types; mine water and well or
drill hole water. Nine water samples were taken from the three
previously sampled sin, shafts reported In USGS Open File Report 78-294
(Figure 2). Mine shaft samples wire collected using a USGS aluminum
boom and a two liter PVC kemserer sampler. A Model 4041 dIgital
Hydrolab was used for measuring field parameters at 20 foot Increments
in each shaft from surface to bottom. The water level was recorded and
samples were taken at the surface of each shaft. When stratified levels
5
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Tar Creek Mining Waste NFL Site Summary Report
Reference 3
Excerpts From Tar Creek Field Investigation Task 1.1:
Effects of Acid Mine Discharge on the Surface Water Resources
in the Tar Creek Area, Ottawa County, Oklahoma;
Oklahoma Water Resources Board, Water Quality Division;
March 1983
-------
obtained. Loading rates for site 4S were computed using the overall
average pollutant concentrations and average flow data collected at the
weir between December 11, 1982, and February 16, 1983. For site 14,
loading rates were computed using the overall average pollutant
concentrations and average flow data measured at the weir between
September 9, 1982, through February 14, 1983. The calculated loading
rates for various pollutants are listed in Table 5.
It should be noted that the mean flow computed at site 4S is only valid
for those months during which the spring is flowing. During these
months the loading from site 4S is generally greater than the loading
from site 14.
EFFECTS OF ACID MINE DRAINAGE FROM THE PICHER FIELD ON STREAI’tWATER
Mine drainage has had a severe impact on Tar Creek since late 1979.
Soon after discharge commenced, most of the biota in the creek were
killed. The banks and bottom of the stream turned red due to ferric
hydroxide precipitates. Red stains have been observed on bridge
abutments and cliffs in Grand River downstream from its confluence with
Tar Creek.
D1s harge of acid mine water with a high concentration of ferrous iron
(Fe 2 ions) to a body of surface water can result in substantial changes
in surface water quality, especially if the surface waters have a low
buffering capacity. The absence of significant amounts of bicarbonate
in Tar Creek results in an extremely low buffering capacity.
Cons quently, the vater course is very sensitive to any external sources
of H ions and OH ions. A rapid change in pH an be expected under
such conditions. When grou dwater with high Fe 2 ion concentrations
reaches the sur ace, the Fe 2 ions in solution are oxidized to form
ferric iron (Fe ions). These Ions, in turn, form an insoluble
hydroxide and produ e hydr .n ions according to the reaction:
4Fe 2 P0 2 +4 14 .4Fe +21120
4F.’ + 121120 . . 4F.(OH) 3 4 • 1211’
The release of hydrogen ions could substantially decrease the pH of the
surface water body, and jn the process, the surface water can become
oxygen depleted as the Fe 2 ions are oxidized.
The pH has usually remained moderate near th. discharge points, sites 4S
and 14, because there is not sufficient oxygen present to rapidly
oxidize the Fe 2 ions and because sewage treatment effluent, with a
higher pH, is discharged to the drainage. However, a pH 0 f 2.9 was
recorded in Tar Creek at site 20 In Miami, Oklahoma, which is a
violation of the Oklahoma Water Quality Standards of 6.5 su. It is
thought that eventually the waters of Tar Creek can recover to the
previous quality, once the discharge of acid mine watr ceases.
In Figures 6 and 7 the pH was much lower at site 20 than at upstream
sites, indicating the above reactions take place relatively slowly. In
Figure 8, when flow velocities ar• much reduced, low pH’s occur much
further upstream. A statistical summary for the pH data, as well as for
14
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\
( J
Tar Creek Mining Waste NPL Site Summary Report
Reference 4
Excerpts From Hazard Ranking System Package,
Tar Creek, Ottawa County, Oklahoma; A;
August 2, 1983
-------
Lb’J
TAR CREEK
Ottawa County, lahoma
The Tar Creek Site, located near Picher, Qclahoina, in Ottawa Couhty,
covers 40 square miles. Tar Creek is a segment of the Eagle Picher
1injng District, which covers 100 square miles and extends into 1 issourj
and ansas. The primary concern raised over this site is its potential
for contamination of both surface and zroundwater,
The area produced significant quantities of iron and zinc n the
1920s and 1930s. Major mining operations ceased in the 1970s. ater
from an underlying aquifer began to discharge to the surface through the
abandoned mine shafts in 1979. At this point, the U.S. GeoLog1 aj. Survey
and the Q lahoma Water Resources Board (0WR3) became involved in the sitc
investigation. R3 contracted to conduct additional water monitoring
and sampling.
In 1981, the State of Q lahoma declared the site its number one ool—
lution problem. Negotiations began between the U.S. Environmental Pro-
tection Agency, t 1R3, and the O lahoma State Department of health (OSDH),
which resu.lted in the award of $ 435 , 3 68,on 1 July 1982. This amount was
set aside for two phases of remedial activities at the Tar Creek Site.
OSOR, the primary Superfund State aaency, has staned an interagency
agreement for $173,000 with OWR3 to continue surface and mine water moni-
toring and s ling.
This site was on the Interim Priority List of 160 sites.
-------
( v i
Tar Creek Mining Waste NPL Site Summary Report
Reference S
Excerpts From Geohydrology and Water Quality of the Roubidoux Aquifer,
Northeastern Oklahoma, Open-file Report 90-570;
Scott C. Christenson, David L. Parehurst, and Roy W. Fairchild,
U.S. Geological Survey, Oklahoma City, Oklahoma; 1990
-------
J - / ? 2: 2 F ’ EFA E ON r STE i1, TO
21.1 ’S4
GEOHTDROLOGY AND WATER QUAL.ITT OF TEE ROUBIDOUX AQULm,
NORTEEASTERN O LARo
By Scott C. Christenson, David L. Parkh irst. and RoyT. Fairchild
U.S. GEOLOGICAL SURVEY
Opeu-File Report 90-570
Prepared in coop.iatien iith the
OXLAHOWA CEOLOCICAI. SURVEY
Ok1aho a City, Okiahosa
1990
-------
e5 3-199: :2: 2 FPOI’l E . iC J — DL TO
U.S. DV1&NEBT OF TEE I1fl kIOR
MAJUEL LUJAL JL , Secretary
U.S. GEOLOGICAL J1VET
Dallu L. Peck, Director
For additional foriatic
writs to:
District Chief
U.S. Geological Survey
atr Reao irces Division
202 N! 66th (3141. 7)
Okiahosa City. 73116
Copies of this report can
be purchased fron:
U.S. Geological Survey
Books and Open-File Reports Section
Federal Center. Bldg. 810
Box 25425
Denver, CO 80225
ii
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5 i2.5 ‘ N E k . r. £. -= G : : . TG-1 .-J.4
gross-alpha radioactivity, it is possibl. that th. vat.r from these nine
wells exceeded the gross—alpha radioactivity IC !.. If uranium radioactivity
contributes a large part of gross-alpha radioactivity, ground water that
exceeds the gross-alpha radioactivity MCI. would be rare.
The MCL for radium is 5 pCi/I. for the sum of radium-226 and radium-228
radioaetiv ty. Seven wells that bad large gross-alpha radioactivity and two
wells that had large censored values for gross—alpha radioactivity were
resawpled and analyzed for radiia-226 (an alpha emitter) and radius-228 (a
beta emitter). Concentrations of radiia-228 were reported as censored
values in all nine samples. However, concentrations of radi a-226 exceeded
the 5-pCi/L MCI. in samples from all seven of the tells that had samples with
large uncensored gross-alpha radioactivity.
later-Dn Fity Prob1 s
Three water-quality problems are apparent in the koubidoux aquifer in
northeast Oklahoma: (1) Con a iT1atjOfl by am. water, (2) large
concentrations of sodium and chloride, and (3) large concentrations of
xadina-226. In this section, the spatial occurrence of these problems is
discussed.
Wine-later ont ’4’ tion
Lead and zinc suif ides were lined from the Boone Formation in the
northeast part of the study unit from about 1900 until about 1970. The
nines vere devatered during mining operations by extensive pumping, but
later filled with water when 1 ping ceased. The compositions of the mine
waters in the Boone Formation are detailed in Playton. Davis, and McClaflin
(1980) and in Parkhnrst (1987). Sulfate is the do’ ’ t anion in the mine
waters, and calcium. magnesium, iron,, and zinc are the dominant cations.
Large concentrations of cadmium, copper, fluoride, lead, manganese, and
nickel have been 2n- yzed in some mine water.
Because the hydraulic head in the Boone Formation is higher than the
head in the knbido aquifer, water will tend to move from the line
workings in the Boone Formation downward through pores and fractures in the
rock units, toward the Roubido aquifer. The Q attanooga Shale and the
Northview Shale are stxatigraphically below the Boone Formation, and have
very small vertical hydraulic conductivity. Although they are not
impervious, they could slow the downward movement of water. However, the
two shale formations are absent in a large part of the the 4 n 4 ig area.
Besides flow through the pores and fractures of the rock units, mine
water could reach the Roubidoux aquifer through leaky well casings.
According to Reed. Schoff, and Branson (1955), about 100 wells were drilled
into the Roubjdoux aquifer in the m 4 ”g area to supply water for . iflang
oDerations. Leaks in the casings at the level of the mine workings would
allow movement of line water down into the koubidoux aquifer. Movement of
this type was demonstrated in two abandoned wells in the “ ring area.
29R-23E-16 DDD 1 and 29N-23E-32 AAC 1. These wells were logged with a
down-bole flotmeter and the data show du.i,.rd water flow in both wells.
4$
--
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2 3 FROfl EFI EGIGI. -iAZ •i STE t
The flow rate in each well was estimated to be lees than 2 gallons per
minute. The U.S. Environmental Protection Agency has funded work to locate
and plug any abandoned veils in the mii ing area that penetrate the Ronbidoux
aquifer. Both wells described here were plugged in 1984.
Several municipa.lities in the r 4 n ng area hare experienced
water-quality problems related to the mines. In two of the public-supply
wells for the City of Comeerce, concentrations of sulfate, iron, zinc, and
dissolved solids increased between July 1981 and October 1982. Repairs were
made in the casings of these wells and the water quality returned to
acceptable limits for public supply. The problems were apparently due to
mine water entering the wells through leaks in the casings or thxongh the
grout . seals of the veils.
Another municipality that has experienced_water-qiality problems
related to the ai_nes is uapaw. then a water-supply Tell. 291-23E-25 BDB 1.
was completed in toveaber 1977. the iron concentration in water from the
ve].l was about 100 ug/L (micrograms per liter) and the pB vas 7.8. By July
1981, the pH was 7.0 and th. iron concentrations us 20.000 ugfL. The well
was abandoned and plugged. The large iron concentrations and lowered pH
indicate mine-water contamination.
The background concentrations of sulfate in the Roubidoux aquifer are
relatively low. Three samples from the Picher water-supply wells, which
were taken between 1942 and 1951. had sulfate concentrations ranging from 11
to 6 mg/L. These concentrations are similar to the median concentration of
16 mg/L for all of the available data (table 7). line-water concentrations
of sulfate are large. appro’ 4 t.ly 3,000 ug/L layton, Davis and
McClaflin, 1980). If sulfate migrates into the lonbidoux aquifer, it is
expected to be conservative (unreactive). Therefore, increasing sulfate
concentration is an indicator of mine-rater contamination. Samples taken
during this study (1981 and 1982) from the Picher water-supply veils had
sulfate concentrations ranging from 47 to 92 ig/L. The increase in sulfate
concentrations between the early samples and the samples of this study
indicate mine—water contamination. Iron concentrations in the samples of
this study were slightly greater than the median, but no other trace
elenents shored increased concentrations. In 1985, one of Picher ‘i three
water-supply wells began producing water with large concentrations of
sulfate, iron, and dissolved solids. This v.13. was subsequently abandoned
and a nem veil was drilled in a new location.
At present (1990), all instances of ground-water conta ii tion by mine
water can be laind by faulty seals or leaky casings in wells that pass
through the zone of aim. vor ngs and down to the Ronbidoux aquifer. All of
the wells that have had robleas with mine-water cont ’i’ tion are within
the perimeter of the ii ing area. lone of the data available to date
indicate that mine water has migrated from the Boone Formation through the
pores and fractures of the intervening geologic units to the Roubidoux
aquifer.
46
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