PB95-964410
EPA/ROD/R08-95/097
January 1995
EPA Superfund
Record of Decision:
Summitville Mine Superfund
Site (O.U. 2), Summitville, CO,
12/15/1994
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ADMINISTRATIVE RECORD
INTERIM RECORD OF DECISION
FOR
CROPSY WASTE PILE, BEAVER MUD DUMP/
SUMMTTVILLE DAM IMPOUNDMENT,
AND MINE PITS
Summitville Mine Superfund Site
Summitville, Colorado
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INTERIM RECORD OF DECISION
for
CROPSY WASTE PILE, BEAVER MUD DUMP/
SUMMTTVILLE DAM IMPOUNDMENT,
AND MINE PITS
Summitville Mine Superfund Site
Summitville, Colorado
DECLARATION FOR THE INTERIM RECORD OF DECISION
Site Name and Location
Summitville Mine Superfund Site, Summitville, Rio Grande County, Colorado.
Statement of Basis and Purpose
This decision document presents the selected interim remedial action, for reducing or eliminating
acid mine drainage from the Cropsy Waste Pile (CWP), Summitville Dam Impoundment (SDI),
Beaver Mud Dump (BMD), and Mine Pits at the Summitville Mine Superfund Site (Site) in Rio
Grande County, Colorado chosen in accordance with the Comprehensive Environmental
Response, Compensation and Liability Act of 1980 (CERCLA), 42 U.S.C. § 9601 et seq., as
amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA) and the
National Oil and Hazardous Substances Pollution Contingency Plan (NCP)(40 CFR Part 300).
This decision is based on the administrative record for this Site.
The State of Colorado Department of Public Health and Environment concurs with the selected
interim remedial action.
Assessment of the Site
Interim remedial actions are appropriate "to protect human health and the environment from an
imminent threat in the short term, while a final remedial solution is being developed." ("Guide to
Developing Superfund No Action, Interim Action and Contingency Remedy RODs", EPA.
OSWER Publication 93553-02FS-3, April 1991). Therefore, actual or threatened releases of
hazardous substances from this Site, if not addressed by implementing the interim remedial
action selected in mis Interim Record of Decision, may present imminent and substantial
endangennent of public health, welfare, or the environment
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Description of Selected Remedy
This interim remedy addresses the reduction or elimination of acid mine drainage (AMD) from
the CWP, SDI, the BMP, and the Mine Pits. The AMD originates from sources altered or
disturbed during mining activities at the Site.
This interim remedy is consistent with current and anticipated future remedial activities to be
implemented to attain sitewide remediation goals
This interim remedial action is anticipated to produce continued reduction of contaminated water
flows to the Alamosa Watershed. The results of the interim remedial action will be routinely
monitored to determine the additional actions needed at each portion of the Site to achieve the
final, sitewide remediation goals.
The selected alternative is feasible, implementable, and cost effective in reducing AMD at the
Site and meets all criteria for the selection of interim response actions required by Section
300.430 of the NCP.
The major components of the selected interim remedy are listed below:
Excavation of the CWP to an elevation of 11,620 feet;
Excavation of the BMD and SDI;
• Line the Bottom of the Mine Pits with a layer of pH neutralizing material; and
• Placement and capping of excavated material in the Mine Pits.
.It is anticipated that the completed interim remedial actions will result in a reduction of
contaminated water flows which currently require treatment and control from the Site. The
results of the interim remedial actions will be monitored to determine the additional actions
necessary at the Site to achieve the final, sitewide remediation goals.
No significant changes have been made to the preferred alternative as it was originally presented
in the CWP, SDI/BMD, and Mine Pits Focused Feasibility Study.
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Statutory Declarations
This interim remedial action is protective of human health and the environment, complies with
Federal and State applicable or relevant and appropriate requirements (ARARs) for this interim .
limited-scope action, and is cost effective. Although this interim action is not intended to
address fully the statutory mandate for permanence and treatment to the maximum extent
practicable, this interim action does utilize treatment and thus is in furtherance of that statutory
mandate. Because this action does not constitute the final remedy for the Site, the statutory
preference for remedies that employ treatment that reduces toxicity, mobility, or volume as a
principal element, although partially addressed in this remedy, will be addressed in the final
response action. Subsequent actions are planned to fully address the threats posed by the
conditions at this Site. Because this remedy will result in hazardous substances remaining on-
site above health-based levels, a review will be conducted to ensure that the interim remedy
continues to provide adequate protection of human health and the environment within five years
after commencement of the remedial action. Because this is an interim ROD, review of this Site
and of this remedy will be ongoing as the EPA continues to develop final remedial alternatives
for the Site.
William P. Yellowtail ^ / December 15,1994
Regional Administrator
U.S. Environmental Protection Agency, Region
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TABLE OF CONTENTS
1.0 DECISION SUMMARY 1
1.1 Site Location and Description ... 1
1.1.1 Climate 1
1.1.2 Topography 1
1.1.3 Geology 2
1.1.4 Hydrogeology ....... 3
1.1.5 Present Surrounding Land Use and Populations 4
12 Site History and Enforcement Activities 4
12.1 Site History 4
122 Enforcement Activities .6
1.3 Community Participation 7
1.4 Scope and Role of Interim Remedial Action within Site Strategy 8
1.4.1 Remedial Action Objectives and Goals .15
IA2 Removal Actions 16
1.4.3 Ongoing Actions 16
1.5 Site Characteristics 17
1.5.1 Nature and Extent of Contamination 17
1.52 Description of Impacted Water 18
1.5.3 Contaminant Transport and Migration 24
1.5.4 ARARs 25
1.6 Summary of Site Risks 38
1.6.1 Screening Ecological Risk Assessment 38
1.6.2 Environmental Risk Assessment 39
1.6.3 Human Health Risk Assessment ...: 1 40
1.7 Description of Alternatives 41
1.7.1 Alternative*! NoAction 42
1.7.2 Alternative #2 Water Treatment 42
1.73 Alternative^ Removal to Mine Pits .42
1.7.4 Alternative^ CropsyValley.Adit 44
1.7.5 Alternative #5 Cropsy Channel Drainage 44
1.8 Comparative Analysis of Alternatives 45
1.8.1 Criteria 1: Overall Protection of Human Health and the Environment
46
1.8.2 Criteria2: Compliance with ARARs 46
1.8.3 Criteria 3: Long-term Effectiveness and Permanence 47
1.8.4 Criteria 4: Reduction of Toxicity, Mobility, and Volume through
Treatment 47
1.8.5 Criteria 5: Short-term Effectiveness 47
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1.8.6 Criteria 6: Implementability 48
1.8.7 Criteria 7: Cost 48
1.8.8 Criteria 8: State Acceptance 48
1.8.9 Criteria 9: Community Acceptance 48
1.9 The Selected Alternative 49
1.10 Statutory Determinations 49
1.10.1 Protection of Human Health and the Environment 49
1.102 Compliance With Applicable or Relevant and Appropriate Requirements
49
1.10.3 Cost Effectiveness 50
1.10.4 Utilization of Permanent Solutions and Alternative Treatment
Technologies or Resource Recovery Technologies to the Maximum Extent
Practicable (MEP) , 50
2.0 RESPONSIVENESS SUMMARY FOR THE CROPS Y WASTE PILE, BEAVER MUD
DUMP, SUMMITVILLE DAM IMPOUNDMENT, AND MINE PITS.
51
2.1 Responsiveness Summary Overview 51
22 Response to CWP, BMD, SDI, and Mine Pits Specific Comments 52
22.1 Summary and Response to Local Community Concerns 52
222 Comprehensive Response to Specific Legal and Technical Questions .. 57
2.3 Summary and Response to General Comments 64
2.4 Summary and Response to ARARs Comments 79
2.5 Summary and Response to Reynolds and Chandler Adit Questions 84
3.0 REFERENCES 92
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LIST OF TABLES
Table 1-
Table 2-
TableSa-
Table 3b -
Table 4-
TableS-
Table6-
TableT-
TableS-
Table 9-
Copper Content - Site Contaminated Water
Cyanide Content - Site Contaminated Water
Site Surface Water and Treatment Plant Flow Rates
Site Surface Water and Treatment Plant Water Volume
Containment Content During High and Low Flow Periods
Copper Concentration at W.F. 5.5
Total Cyanide Concentration at WJ. 5.5
ARARs
Numeric Surface Water Quality Goals and ARARs
Evaluation of Alternatives
ill
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LIST OF FIGURES
Figure 1 - Area Map
Figure 2 - Minesite Footprint
Figure 3 - Geology - Cropsy Valley Section
Figure 4 - Contaminated Surface Water Streams
FigureS- Alamosa River Stream Segment Classifications
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1.0 DECISION SUMMARY
1.1 Site Location and Description
The Summitville Mine Superfund Site is located about 25 miles south of Del Norte, Colorado, in
Rio Grande County (Figure 1). It is located within the San Juan Mountain Range of the Rocky
Mountains, approximately two miles east of the Continental Divide, at an average altitude of
11,500 feet The 1,231 acre mine permitted area is positioned on the northeastern Sank of South
Mountain. The disturbed area at the Site covers approximately 550 acres (Figure 2). On the
North, this area is bounded by the deserted town of Summitville and by Wightman Fork Creek.
It is bounded by Cropsy Creek to the east and the peak of South Mountain to the southwest The
Site is located in the Rio Grande Drainage Basin near the headwaters of the Alamosa River. Two
tributaries drain the Site - Wightman Fork Creek and Cropsy Creek. The confluence of Cropsy
Creek and Wightman Fork is located on the northeastern perimeter downstream of the Site.
Wightman Fork Creek drains into the Alamosa River approximately 4.5 miles below the Cropsy
Creek confluence.
1.1.1 Climate
The Site's climate is characterized by long cold winters and short cool summers. Winter
snowfall is heavy and thunderstorms are common in the-summer (SRK, 1984). Temperatures
range from a high of 70°F and a low of 17°F in the summer to a high of 40°F and a low of-25°F
in the winter. The Site receives an average of 55 inches of precipitation annually, mostly in the
form of snowfall, and has an annual evaporation rate of approximately 24 inches (Remedial
Measures Plan, 1992).
There is a relatively snow-free period of 5-6 months from May through October. This time
period is regarded as the "construction season". Site access and operations during the rest of the
year requires a significant amount of snow removal. Continued water treatment and flow, or
meticulous winterization, is required to prevent water from freezing in the pipes.
1.1.2 Topography
Approximately 550 acres of the Site is comprised of heavily altered terrain due to mining
operations. The Site's pre-1870 topography consisted of upland surfaces, wetlands, and South
Mountain peak. The predominant Site ground cover was alpine tundra at the higher elevations
with coniferous forest and subalpine meadow in the lower elevations. The mountains which
surround the Site, including Cropsy Mountain to the south, are between 12300 feet and 12,700
feet in elevation.
The Wightman Fork drainage covers approximately 3.0 square miles upstream from the
Wightman Fork diversion. The catchment elevations range from 11,225 feet to 12,754 feet The
Cropsy Creek drainage area entails 0.85 square miles on the northeast slopes of the Cropsy
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Mountain and the southern slopes of South Mountain. Elevations within this drainage range
from 12,578 feet down to 11,200 feet at the Cropsy Creek confluence with Wightman Fork
(Klohn Leonhoff, 1984). Wightman Fork drains into the Alamosa River approximately 4.5 miles
from the Cropsy Creek confluence.
Disruption of the topography began, on a limited scale, in 1870 with placer gold mining in
stream- formed alluvial deposits. This placer mining was followed by open cut mining on gold-
bearing quartz veins. Underground mining followed. As mining production depths increased,
several processing mills were constructed to handle the increased capacity and produce a
concentrate suitable for transit This initial mining phase lasted through 1890. Additional
underground mining occurred from 1925 to 1940 and resulted in surface deposition of waste
rock near the adit entrances. Additionally, piles of mill tailings were placed downgradient from
the stamp mills and the 1934 flotan'on-cyanidation mill, which was located at the site of the
present HMD.
Further surface disruption of the topography resulted from work in the late 1960's when
Wightman Fork was diverted north to allow construction of a dam and tailings pond. With this
new impoundment, mill tailings were put on the BMD down to the area above the SDL The SDI
was formally referred to as the Cleveland CliSs Tailings Pond.
The most dramatic alterations of the surface started in 1984 with the construction of the mine pits
and dumps associated with Summitville Consolidated Mining Company, Inc.'s (SCMCFs) open
pit heap leach gold mine. The main topographical feature is the highwall of South Mountain
This highwall is fractured and has a one to one (horizontal to vertical) slope.
1.1.3 Geology
Summitville is located near the margin of the Platoro-Summitville caldera complex. Rocks in
the mine area consist of South Mountain Quartz Latite Porphyry. The porphyry is underlain by
the Summitville Andesite. The contact between the latite and andesite is intrusive, faulted hi
some areas and is nearly vertical. On the north side, the contact is fault-bounded by the
Missionary Fault South Mountain is bounded on the southwest by a large northwest-southeast
trending regional fault called the South Mountain Fault The South Mountain Quartz Latite
Porphyry is bounded to the west, on both sides of the South Mountain Fault, by slightly older
Park Creek Rhyodacite. It is overlain at higher elevations by erosional remnants of slightly
younger Cropsy Mountain Rhyolite (Stofiregen, 1987). Figure 3 shows a geologic section of the
Cropsy Valley.
South Mountain volcanic dome emplacement, alteration, and mineralization occurred hi rapid
sequence approximately 22.5 million years ago (Rye, et al., 1990). Magmaric, sulfate-laden
water expulsed from the quartz latite magmas was hot and highly acidic (pH*2, temperature of
250° C - Stofiregen, 1987), and caused extensive alteration to the quartz latite. Alteration occurs
in four sequential zones: the massive vuggy silica zone, the quartz-alunite zone, the quartz-
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kaolinite zone, and the clay alteration zone. The massive vuggy silica zone is often a highly
porous zone in which all major elements but silica and iron were leached by acidic solutions and
replaced in places by excess silica. This zone occurs in irregular pipes and lenticular pods, and
generally shows greater vertical than lateral continuity (Stoffregen, 1990). The next outwardly
occurring zone is the quartz-alunite zone, in which feldspars of the quartz latite porphyry were
replaced by alunite. This zone grades outward to a thin quartz-kaolinite zone, which is not
always present, and then into an illite-montmorillonite-chlorite zone in which feldspar and biotite
grains were replaced by illite and quartz, with lesser kaolinite and montmorillonite. The quartz-
alunite and clay alteration zones are the most volumetrically significant Fine-grained pyrite is
disseminated through the groundmass hi all zones (Stoffregen, 1987).
Summitville mineralization is an example of epithermal Au-Ag-Cu mineralization associated
with advanced argillic alteration. Mixed magmatic and surface water (derived from snowmelt
and rainfall), less acidic and more reducing than the magmatic water that produced the alteration
zones, deposited metals and metallic sulfides at shallow (<1 km) depths (Rye, et al., 1990).
Mineralisation is associated mostly with the porous vuggy silica zone, and occurs as covellite +
luzonite + native gold changing with depth to covellite + tennanite. Gold also occurs in a near-
surface barite + goethite + jarosite assemblage that crosscuts the vuggy silica zone (Stoffregen,
1987).
Post-volcanic geologic processes have been largely erosional. The two major streams that drain
the Site, Cropsy Creek and Wightman Fork, tend to follow the quartz latite/andesite contact
Numerous springs and seeps occur at this junction between the fractured quartz latite porphyry
aquifer and the underlying dense andesite aquitard.
Site cover material consists of topsoil, silt, clays, and gravel. The topsoil is described as
grey/brown/orange, non-plastic with a trace of roots and sand. Clays are of low to medium
plasticity with some gravel.
1.1.4 Hydrogeologv
Ground water at the Site is present as a series of intermittent, .shallow, perched aquifers. Shallow
ground water occurs in surficial deposits consisting of colluvium, "slope wash" alluvium and/or
glacial ground moraine; and weathered parts of the Summitville Andesite. These shallow
systems eventually discharge to surface water. The upper perched aquifer system also contributes
to the ground-water recharge of the fractured bedrock system. Numerous springs and seeps
cover the entire Minesite, the greatest number at the locus of the distal edge of the dome. Most
of the springs and seeps flow hi direct response to precipitation, with high and low flows
corresponding to Ugh and low flow of me surface water system in the area.
A natural surface water drainage system exists along the southern portion of the Summitville
Site. The surface water drainage system inclines Cropsy Creek and Wightman Fork. Extensive
re-working of both drainage systems has been conducted.
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1.1.5 Present Surrounding Land Use and Populations
The Site is surrounded by National Forest Service land (Rio Grande National Forest). The
multiple-use designation of this land gives it a high level of desirability for snow mobiling, cross
country skiing, Hiking, camping, horseback riding and picnicking. Additionally, logging activity
is on-going adjacent to Park Creek Road and other roads adjacent to the Site. During the summer
months, domestic cattle and sheep graze in the surrounding area and during the winter months,
the surrounding area is heavily used for hunting.
The distance to the nearest off-Site building is 2.1 miles to the east (EPA, 1992). The water from
the Site flows past the town of Jasper into Terrace Reservoir, both of which are recreational
areas. Private residences and a Phillips University Camp use water from wells adjacent to the
Alamosa River. Below the Terrace Reservoir, the river flows past the town of Capulin which
contains two municipal wells and many domestic wells. Throughout this drainage area, homes,
farmsteads and ranches depend upon alluvial wells or river water for potable or agricultural water
production. However, recent EPA analysis indicates mat the Site has not impacted alluvial
drinking water supply wells (Morrison Knudsen, 1994). Additionally, water from the Alamosa
River is used within the Monte Vista Wildlife Refuge and in the La Jara Creek system through
the Empire Canal (District Court, Rio Grande Co., 1992).
1.2 Site History and Enforcement Activities
1.2.1. Site History
Placer gold was discovered in Wightman Gulch hi the summer of 1870 (Guiteras, 1938). The
lode deposit was found near the headwaters in 1873 and by 1875 open cut workings had been
established. The ore consisted of native gold in vein quartz, reportedly associated with limonite
and other ion oxides, which comprised the surficial, oxidized zone of the deposit Because this
zone reportedly extended to 450 feet below the surface, adits and shafts had to be driven into the
veins (Garrey, 1933). There was only minor production in the mine area from 1890 to 1925.
In 1897, the Reynolds Adit was driven into the Tewksbury vein, located below the central
portion of the contemporary Summitville pit The Adit was completed in 1906 (Knight Piesold,
1993). Reports of acidic water exiting the adit soon followed (Garrey, 1933).
A significant gold find occurred hi 1926 when high grade ore was struck. From 1926 to 1931,
864 tons of ore was extracted. The Reynolds Adit was rehabilitated to provide haulage and
development access. Plans were made to connect the Reynolds to the Iowa Adit, 540 vertical
feet above the Reynolds. This connection was completed in 1938. Iowa ores were then dropped
down to the Reynolds level for haulage. The Reynolds and the Iowa Adits also provided
drainage for the main workings (Knight Piesold, 1993).
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In 1934, a 100 ton-per-day flotation/cyanidation mill and gold retort was installed at the site of
the present HMD. Records indicate that dewatering filtrate from the flotation circuit was
discharged directly into Wightman Fork throughout the mid-1930's.
In 1941, three tunnels were in operation: the Iowa, Narrow Gauge, and Reynolds. During World
War n, the government mandated the termination of mining of non-essential minerals to focus on
essential minerals needed for the war effort Gold production ceased.
From 1943 to 1945, a high grade copper vein found in the Narrow Gauge and Reynolds was
developed. By 1944, only the Narrow Gauge Tunnel was operating. In 1947, the Reynolds was
again rehabilitated. Approximately 4,000 feet of rail needed replacement due to deterioration
from acidic water. By 1949, the water flow discharge from the Reynolds ranged from 100-200
gallons per minute (gpm) (Stevens, T A., 1960).
From 1950 to 1984, the Minesite was the target of several exploration and underground
rehabilitation programs. Production of copper, gold, and silver was sporadic. An extensive
drilling program was conducted in the late 1970's and early 1980's to delineate a potentially
minable gold deposit (Knight Piesold, 1993).
The underground and surface operations during the original discovery of gold to the early 1980's
resulted in surface deposition of waste rock near adit entrances and deposition of mill tailings
downgradient of the original mill. An attempt to process ore to extract copper content in the late
1960's and early 1970's resulted hi a diversion of Wightman Fork from its original route to
further north of the existing tailings, construction of the SDI (1969) and deposition of mill
tailings east of existing tailings piles.
During recent operations (1984-1991), SCMCI, a wholly-owned subsidiary of Galactic
Resources, Inc., developed the remaining mineral reserves as a large tonnage open pit heap leach
gold mine Gold containing ore (9.7 million tons) was mined, crushed and heaped onto a
constructed clay-and-synthetic-lined pad. A solution containing 0.1 -0.5% sodium cyanide was
applied to crushed ore on the Heap Leach Pad (HLP) and was allowed to percolate through the
ore to leach out gold. The solution was then pumped from the ore and gold was removed from
the leachate with activated carbon. The leaching solution was rejuvenated by restoring the target
cyanide level and recycled through the heap. Gold was stripped from the carbon, precipitated
from the stripping solution, smelted to make dore metal, and sold.
The Summitville HLP is a "valley fill" design. This design differs from more widely employed
designs in that it is more of a lined depression, or rock filled pond, man a lined leaching "pad".
Utilization of a valley fill design usually results from topographic limitations that make
construction of a free draining pad difficult The process solution was pumped directly from the
HLP to the gold recovery plant The more common leach pad design enables water percolated
through ore to constantly drain to a "pregnant solution pond" outside of the HLP, rather than
being held in the same containment area as the crushed ore. The design of the HLP as a
continuous water containment structure prevents the natural drainage of water from the cyanide
bearing pad and complicates the closure of the .ore pile.
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The HLP containment feature was constructed in a portion of the valley occupied by Cropsy
Creek. Cropsy Creek was moved to allow construction of the HLP. After diversion of Cropsy
Creek, a portion of the valley was enclosed by dikes. The area between the dikes was contoured
and lined and became the HLP.
Open pit mining operations conducted by SCMCI did not expose standing ground water in the
mine pit Infiltration of surface water (derived from snowmelt and rainfall) through the pit may
have resulted in elevated dissolved metal concentration in the water draining from the Reynolds
Adit This trend is observed when compared to the available pre-open pit drainage data.
During the SCMCI operation, topsoil was stripped and placed into stockpiles. Other overburden
and waste material was used for road and dike construction, placed into the Cropsy Waste Dump
and the North Pit Waste Dump (NPWD), and placed over the historic mill tailing* to form the
Beaver Mud Dump. Difficulties in processing some of the ore resulted in formation of the Clay
Ore Stockpile, near the present solution pumphouse location, and an in-pit stockpile. Figure 2
illustrates these areas.
The last ore tonnage was placed on the HLP in October 1991. Addition of sodium cyanide to the
ore continued until March 1992. After mining operations were concluded, SCMCI proceeded
toward Site cleanup and closure by converting the gold recovery plant to a cyanide destruction
facility for HLP detoxification, converting the existing alkaline chlorination water treatment
plant to a sulfide precipitation process, and installing a treatment plant to process Reynolds Adit
drainage.
1.2.2 Enforcement Activities
In February of 1991, after monitoring rising concentrations of cadmium, copper, zinc and
cyanide in Wightman Fork, the State of Colorado cited violations of water quality legislation and
issued a Cease and Desist Order to SCMQ (Holm, 1991).-.
On December 3,1992, SCMCI declared bankruptcy and announced that financial support of Site
operations would not continue beyond December 15,1992. On December 16,1992 the EPA
Region VTH Emergency Response Branch, as a part of an Emergency Response Removal Action
(ERRA), began treating cyanide-contaminated leachate from the HLP and AMD from three
significant sources: the French Drain Sump, the Cropsy Waste Pile, and the Reynolds Adit
(Ecology and Environment, 1993).
Site operation oversight was undertaken by the United States Bureau of Reclamation (USBR)
under an inter-agency agreement with the EPA. In December 1992, Environmental Chemical
Corporation (ECC), under the direction of the USBR, began conducting engineering evaluations
of the water treatment processes and subsequently began improvements to water treatment
processes and facilities.
The Site was added to the Superfund National Priorities List (NPL) on May 31,1994.
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U Community Participation
The Proposed Plan for the Summitville Mine Site was released to the public in August 1994.
The Proposed Plan, the Focused Feasibility Study, and other documents in the Administrative
Record are available at information repositories at the following locations: Del Norte Public
Library located in Del Norte, Colorado; the Conejos County Agricultural and Soil Conservation
Service located in La Jara, Colorado; and the EPASuperfund Records Center located in Denver,
Colorado.
Public meetings were held in Alamosa, Colorado on Septemer 8 and October 12 to present the
Proposed Plans and to take public comment The comment period was extended 30 days to
October 23,1994.
Highlights of community participation are summarized as follows:
• When EPA took over the Site hi December 1992, there was a great deal of public interest,
mostly from farmers downstream of the Site who were concerned that their irrigation
water would be contaminated. As EPA worked to reduce the chance for a large toxic spill
and began more water treatment at the Site, the farming community became satisfied that
there was no imminent danger of contaminating their water supply. Since that time there
has been a decreased interest about the Site from the general public. The interest in the
Site nationally has been very high due to the media using Summitville as a "red flag11 for
the need for mining reform.
In June 1993, a Superfund informational workshop was provided to the public in La Jara,
Colorado.
On August 2,1993, a public meeting was held in Alamosa, Colorado describing
alternatives for reducing AMD from the CWP, the BMD, the SDI and the Mine Pits. An
Engineering Evaluation/Cost Assessment (EE/CA) fact sheet was published. Public
comment was taken until September 3,1993.
• The Community Relations Plan for Summitville was written and distributed in September
1993. The Community Relations Plan provides a guide for EPA's community
involvement program based on interviews with local citizens.
A Technical Assistance Grant (TAG) was awarded for the Site hi February 1994. This
group is now well organized and has hired several consultants. The TAG Group has been
active in the area hi an attempt to generate interest in the Site. They have published
regular Summitville columns in the Valley Courier newspaper and have held
informational meetings.
• EPA held a briefing for Congressional aides in May 1994.
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• Press releases have been written dealing with the following:
Proposal to place on the National Priorities List (NPL),
Listing on the NPLy
- Announcing meetings,
. Availability of materials,
Comment periods,
Availability of work through bid process,
Bid awards, and
Status of work at the Site.
• Five Site Status Updates have been written and distributed to over 200 interested parties
as well as a year end report for 1993.
• Articles about the mine were written by local newspaper writers and appeared at least
weekly for the past year. Files of these newspaper articles are available in the
Community Relations office and will be placed in the information repositories.
• In December 1993, the EPA produced and distributed copies of videos of the Summitville
Mine Site. One hundred fifty copies have been circulated to school official, and
interested community members. The video gives an overview of the contamination at the
Site, a brief history of the Site, and a "video tour".
1.4 Scope and Role of Interim Remedial Action within Site Strategy
The original mine permitted area included 1,231 acres; the area referred to as the Site is
comprised of approximately 550 acres of land disturbed by historic as well as recent mining
activities. The most common type of contamination associated with production of a metal mine
such as Summitville is the formation and discharge of large volumes of acidic water. The acid
generation can occur either chemically or biologically; as part of the living processes of certain
microorganisms. The acid is formed chemically when water,-such as rainfall or snowmelt, and
air come into contact with metallic sulfide ores. The sulfide (S"2) then reacts to form sulfuric acid
and sulfates. The sulfuric acid and sulfates react with the surrounding rock or soils to generate
the metal concentrations within the acidic water and is then known as Acid Mine Drainage
(AMD). This process continues as long as mere is sulfide or sulfates, water, and air.
The primary metallic sulfides and secondary sulfates found at the Summitville Mine Site are
pyrite (iron sulfide), alunite (potassium aluminum sulfate), and jarosite (potassium iron sulfate).
There are fourteen areas of concern at the Summitville minesite including twelve which either
generate or may potentially generate AMD. The fourteen areas are briefly described below in
their general order of priority:
1. HEAP LEACH PAD (HLP): The HLP is approximately 55 acres in size and 127 feet
deep at its lowest point The Cropsy Creek was diverted around the HLP area and the
HLP was then constructed in the former Cropsy Creek drainage bed. The HLP is
underlain by a French Drain system and extends onto the toe of the CWP which is located
8
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upgradient within the Cropsy Creek drainage bed. The leach pad liner is leaking, causing
the water within the French Drain to become contaminated with cyanide. The HLP
consists of ore containing high levels of metallic sulfides sitting hi a vat of cyanide and
heavy metals contaminated water. In December of 1992, the EPA took over operations of
the Site water treatment plant to prevent overflow of the contaminated water to the
Wightman Fork and, ultimately the Alamosa River during Spring runoff. Currently the
HLP is maintained at a pH of 9 to prevent the evolution of hydrogen cyanide gas. It is
currently proposed that the Heap be detoxified as one of four interim actions. This action
will also address the potential acidification of the heap once the cyanide is removed and a
high pH is no longer maintained. The former continuous overflow of AMD to the HLP
from the adjacent CWP is currently being addressed as discussed hi 3. below.
2. REYNOLDS ADIT SYSTEM: The Reynolds System is composed of the
underground workings which still exist under the large open Mine Pit excavated by
SCMCI, and the remaining adits which access those workings. The Adits include the
Reynolds, the Dexter Crosscut, the Chandler, and the Iowa. The Reynolds Adit is the
main adit which was driven to drain the workings and provide an access and haulage
route. The Dexter Crosscut, a drift branching westward from approximately 100 feet into
the Reynolds Adit, also provided drainage, access, and haulage. The Chandler Adit
accesses the upper areas of the underground workings at a higher elevation than the
Reynolds Adit. The Iowa Adit accesses even higher levels of the workings and areas near
the rim of the Mine Pit The Mine Pit was hydraulically connected to the Reynolds
System and contributed much of the AMD observed at the Reynolds Adit The EPA
operated an interim treatment plant to treat the average 120 gallons per minute (gpm) of
AMD which exited the Reynolds Adit
Based upon the estimated release of 44.5 percent of total copper loadings directly from
the Reynolds Adit, it was determined that plugging.ofthis system be conducted as a time-
critical Removal action. A contract to plug the Reynolds Adit System was awarded on
October 4,1993 and work began on November 22,1993. After extensive technical
considerations, only the Reynolds and Chandler Adits were ultimately plugged. The
Dexter Adit was found to terminate approximately 450 feet from its intersection with the
Reynolds so no plug was needed. Upon completion of the Reynolds plug, there was an
immediate decrease in flow and a 65 percent reduction in copper concentrations from the
Site overall. Copper loadings directly attributed to the Reynolds Adit were decreased by
97 percent
On May 25,1994, the Chandler Adit was discovered to be discharging high volumes of
water from porous/fractured rock surrounding the plug. The leak was initially estimated
at 340 gallons per minute (gpm) and peaked at 725 gpm hi June 1994 with high
concentrations of metals and low pH. However, this new contaminant source produced
less flow and less copper concentrations than experienced from the Reynolds Adit system
during the previous year. Work to fortify the Chandler plug was initiated in November
1994 and plug performance will be closely monitored through the 1995 spring runoff
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season. Since November 20,1994, AMD exiting the Chandler has been treated through
the PITS water treatment plant and no longer discharges directly to Wightman Fork.
3. CROPSY WASTE PILE (CWP): The CWP was composed of approximately 6.5
million tons of low grade ore, overburden, and waste rock excavated from the mqi" Mine
Pit during SCMCI's mining operations. The CWP covered approximately 35 acres and
was piled as high as 120 feet from the bottom of the old Cropsy Creek drainage bed in
which it was placed. Although the CWP had been capped to prevent percolation of
snowmelt and rainfall, upward infiltration of ground water has begun the process of
acidifying the CWP and AMD discharges are occurring. When the HLP was extended
onto the toe of the CWP, the French Drain system beneath the CWP was severed from the
system below the HLP. As a result, water backed up behind the liner of the HLP into the
CWP saturating that part of the CWP and creating a 5 million gallon reservoir of highly
contaminated water within the bottom of the CWP.
To prevent the overflow of AMD into the HLP, it was determined that the CWP would be
addressed as a non-time-critical Removal action. During development of the EE/CA
report, it became apparent that the same response action would also apply to the SDI and
BMD, and that concurrent implementation would be cost effective. The response action
selected in the Action Memorandum #4 issued by the EPA on September 24,1993,
required consolidation of the various waste piles in the Mine Pits. Because this work
would require more than one construction season to complete, the design and actual
construction were phased. Phase I work was initiated on October 1,1993 and concluded
in February 1994. During this time, approximately 927,000 cubic yards of the Cropsy
Waste Pile was placed in the Mine Pits. The waste materials were isolated from ground
water by lining the surface of the Mine Pits with impermeable material identified on-site.
A protective layer of lime kiln dust was placed on the liner prior to placement of the
waste materials to neutralize any AMD generated during this work.
Phase n work was initiated in August 1994. The CWP was completed in November 1994
and the SDI/BMD are expected to be completed in December 1994. Phase fl will have
moved an additional 3.5 million cubic yards of waste material to the Mine Pits.
Phase IQ work will include construction of a final, impermeable cap and vegetation of the
"footprint" areas below the CWP, BMD, and SDI. Since Phase HI removal action work
had not begun, the EPA evaluated the removal action alternative selected in the action
memo as one of its remedial alternatives for the CWP, SDI, BMD, and Mine Pits. This
alternative was ultimately selected as the interim response action for these areas of the
Site.
4. WIGHTMAN FORK, ALAMOSA RIVER, TERRACE RESERVOIR (OFF-
SITE): The release of large quantities of AMD from the Site have occurred since the
1870's when mining first began, though the concentrations have significantly increased
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since the beginning of mining activities by SCMCI. Much of the AMD generated at the
Site finds its way into the Cropsy Creek or Wightman Fork creek, unless it is diverted for
treatment The Cropsy Creek flows into the Wightman Fork at the southeastern comer of
the Site. The Wightman Fork, located on the northern boundary of the Site, empties into
the Alamosa River approximately 4.5 miles from the Site. The Alamosa, in turn, flows
into the Terrace Reservoir about 18 miles from the Site. There are three small wetland
habitats along the Alamosa where several endangered species, including the bald eagle,
whooping crane, and peregrine falcon have been identified. The closest wetland is 1.8
miles from the Wightman Fork confluence. The other wetland areas are 4.2 and nine
miles downstream from the confluence. These wetlands are all upstream of the Terrace
Reservoir. Concerns regarding other water usage requirements, including drinking water
and farm irrigation needs, are being investigated.
5. BEAVER MUD DUMP (BMD): The BMD encompasses 15 acres and consists of
approximately 900,000 cubic yards of historic metallic sulfide tailings as well as
overburden from SCMCFs operations. It is located immediately adjacent to and south of
the Wightman Fork Creek and is a significant source of AMD. The BMD is also
infiltrated by ground water and discharges AMD to the SDL This area is being addressed
as part of the CWP Removal action and proposed interim action.
6. SUMMITVILLE DAM IMPOUNDMENT (SDI): Formerly referred to as
Cleveland Cliffs Tailings Pond, the SDI is a historic sulfide rich tailings pond located
within the former Wightman Fork drainage bed. The Wightman Fork was routed around
the impoundment While the SDI only contains about 133,000 cubic yards of material, it
is thought to be hydraulically connected to the Wightman Fork and, therefore, providing
AMD directly into the creek. This area is being addressed as part of the CWP Removal
action and interim remedial action.
7. FRENCH DRAIN SUMP: The French Drain is a collection system which was
constructed underneath the CWP and HLP to intercept and route ground water flowing
from seeps below these units (CWP and HLP) back into the diverted Cropsy Creek.
Because much of this ground water flows through the CWP or becomes contaminated
with cyanide when passing below the HLP, it is currently routed to the water treatment
systems or pumped directly into the HLP. While the French Drain is not itself a source
generating contaminant*^ it serves as a point source discharge for contaminated water in a
fashion similar to that of the Reynolds Adit system.
8. CLAY ORE STOCKPILE (StockpUe): The Stockpile is located just north of the
CWP and HLP border and was originally meant to be ore for placement on the HLP.
Because of its high clay content SCMCI was unable to provide the special handling
needed before the ore could be leached. The one million ton Stockpile was purposely
created because of its high content of metallic sulfides and is considered to be a source of
AMD.
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9. MINE PITS : This is the location of the former orebody mined by SCMCI arid the
location of the veins that were historically mined within the Summitville mining district
The 100-acre Mine Pit has consumed most of the underground mine workings with the
exception of the Reynolds Adit System described above. This area was and is highly
mineralized and contains high concentrations of metallic sulfides. Approximately 70
million gallons of water (snow or rain) per year entered the Pit, passed through the
remaining underground workings, and exited as AMD from the Reynolds Adit, prior to
plugging. The Pit is the origin of the rock in each of the tailings areas on-site and the ore
in the HLP. This area is being addressed as part of the CWP Removal Action and interim
action. At this time, the Pit has been filled by the waste material and is free draining of
surface water.
10. THE NORTH WASTE DUMP (DUMP): This refers to a large area located north
of the Pit composed of waste rock and overburden from the Mine Pit It contains
relatively moderate amounts of metallic sulfides and is a potential source of AMD. The
northern portion of the dump, primarily the slope below the 11,580 bench, was reclaimed
and upper portions of the dump were regraded with some subsoil and topsoil placement
during the 1991 operational season. Vegetation success has been limited due to high
wind exposure.
11. GOMPERTS PONDS: These are a series of small ponds, located approximately
400 feet north of the HLP, that contained severely acidic and toxic metals contaminated
water and sludges. The ponds were excavated and then covered with soils. It is unknown
if any sludges or contaminated soils remain where the ponds were. If so, this area is
another source of AMD..
12.. ACID ROCK DRAINAGE SEEPS: There are over 48 potential acid rock drainage
seeps identified on the Site. These are areas where ground water naturally comes to the
surface though some may be a result of construction activities at the Site. The seeps have
not yet been evaluated to determine if they are an AMD source.
13. MINE SITE ROADS: Many of the roads at the Site were constructed with waste
rock from the Mine Pit The material in these roads has not yet been evaluated to
determine if they are an AMD source.
14. LAND APPLICATION AREAS: There are areas where cyanide contaminated
AMD was sprayed onto the soils as a treatment method. Aeration, as a result of spraying,
was meant to eliminate the cyanide contamination while the soils were supposed to
attenuate the metals. These areas have not yet been evaluated to determine if they are a
current AMD source.
Once these areas had been identified, the EPA was able to establish Remedial Action Objectives
(RAOs) for the overall Site. Pursuant to 40 CFR section 300.43 (e)(2)(i), the RAOs were
established to provide remedial goals for the Site and were developed in consideration of current
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regulatory guidelines, compliance with ARARs, and other identified limiting factors. The
sitewide RAOs for the Summitville minesite are:
1. Reduce or eliminate deleterious quality water flow from the Summitville minesite into
the Wightman Fork.
2. Reduce or eliminate the need for continued expenditures in water treatment for the
Summitville minesite.
3. ; Reduce or eliminate the acid mine/rock drainage from the manmarig sources on the
Summitville minesite.
4. Reduce or eliminate any human health or adverse environmental effects from mining
operations downstream from the Site, to include the Alamosa River.
5. Encourage early action and acceleration of the Superfund process for the Summitville
Site. •- •
An analysis of metal loadings attributable to each of the AMD source areas resulted in the
development of five primary areas of focus. Many of these source areas are in drainages or are
located where large amounts of surface or ground water are available for continued generation of
AMD. The Cropsy-Wightman stream drainage system for the Site also serves as a way to
transport the generated AMD contaminants off-site. The following table illustrates the copper
loadings and flows from these drainage points as measured by SCMCI in July of 1991. This
approach is also based on the water quality data regarding copper loading into Wightman Fork,
The table lists the contaminant sources, the yearly copper contribution to me creek from each
source, and the relative percentage loading of each source:
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SOURCE
Reynolds Adit
Cropsy Waste Pile
Heap Leach Pad
overflow potential
French Drain
Summitville Dam Impoundment/
Beaver Mud Dump
Other
TOTAL
POUNDS OF COPPER PER
YEAR
143,000
33,400
84,000
14,600
17,000
29,000
321,000
RELATIVE
44.6
10.4
262
4.5
5J
9.0
100.0
Due to the size of the Site and extent of the contamination, the sitewide interim remediation
activities are being addressed in five separate, though related actions. These five actions are:
• Plugging the Reynolds and Chandler Adits
Movement of the CWP, SDL and BMD
• HLP Detoxification/Closure
• Sitewide Reclamation
• Interim Water Treatment
The first action of the containment/isolation and stabilization project was the plugging of the
Reynolds and Chandler Adits. The second action is excavation of the CWP, SDI, and BMD,
with subsequent placement of this material into the Mine Pits. Both of these removal actions are
in progress under Emergency Response authority as discussed above.
The Phase HI work for CWP, SDI, and BMD, as well as the remaining three actions will be
completed as interim remedial actions. The CWP, HLP, and Reclamation work are expected
begin during the 1995 construction season. The Water Treatment action will continue without
interruption though modifications in actual treatment processes may be implemented during
1995.
This IROD addresses the reduction or elimination of dissolved metal contaminants and the
transportation of metal contaminants in surface water from the Site. This interim remedial action
is targeted to mitigate sources of AMD generated at the CWP, BMD, SDI and Mine Pits. The
remediation measures described in this IROD are a continuation to the substantial cleanup
measures undertaken by EPA using Emergency Response Removal Authorities at the CWP,
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BMD, SDI and Mine Pits. The Emergency Responses were taken by EPA to quickly minimise
potential impacts to downgradient receptors. These actions have included the removal of
materials from the CWP, BMD, SDI, placement of waste materials into the Mine Pits and
plugging of the Reynolds and Chandler Adits. This interim remedial action is intended to
complete the clean up of the CWP, BMD, SDI and Mine Pits initiated by EPA under its removal
authorities.
1.4.1 Remedial Action Objectives and Goals
Specific remedial objectives for the CWP, BMD, SDI and Mine Pits are confined to removal,
containment or treatment nf contaminated materials and drainage and the elimination or
reduction of AMD. Remedial actions will be implemented hi order to eliminate
metal transport to the Wightman Fork and the Alamosa River. It is expected that the impacts of
transport will be monitored in the Alamosa River below the confluence with Wightman Fork.
The interim RAOs and goals for CWP are as follows:
1 . Reduce and/or eliminate acid rock drainage and metals released from the CWP Drainage
2. Ensure compatibility with the sitewide remedy.
3. Remove, reduce, stabilize and/or contain significant man-made sources of acid rock
drainage to prevent further release.
4. Divert water from flowing into the HLP, thereby reducing treatment costs.
5. Separate or eliminate the CWP drainage impact, (including volume and quality of water)
on structural integrity of the valley drainage system (e.g., dikes, waters diverting from
outside the French Drain underneath the HLP).
6. Implement pre/post monitoring programs at the CWP and at subsequent compliance
points.
The interim RAOs and goals for BMD and SDI are as follows:
1. Ensure compatibility with the sitewide remedy.
2. Remove, reduce, stabilize and/or contain significant manmade sources of acid rock
drainage to prevent further release.
3 . Implement pre/post monitoring programs at the BMD, SDI and at subsequent compliance
points.
4. Reduce and/or eliminate acid rock drainage and metals released from the BMD and SDI
area.
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The interim RAOs and goals for Mine Pits are as follows::
1. Ensure compatibility with the sitewide remedy.
2. Remove, reduce, stabilize and/or contain significant manmade sources of acid rock
drainage to prevent further release.
3. Implement pre/post monitoring programs at the Mine Pits and at subsequent compliance
points.
4. Reduce drainage into the Mine Pits and the consequent AMD loading at the Reynolds
AdiL
1.4.2 Removal Actions
A non-time critical Removal action was initiated for the CWP, HMD, SDI and the Mine Pits in
October 1993. Due to the short construction season associated-with the high elevation of the
Summitville Mine Superfund Site, this response action was designed and was to be implemented
as three separate phases, each phase to be completed during a single construction season. These
response action will reduce AMD from the Site by an estimated 140 million gallons per year.
Phase 1 was initiated in October 1993. During Phase I, approximately 927,000 cubic yards of
waste material from the Cropsy Waste Pile were excavated and placed into the Mine Pits. The
Mine Pits were previously lined with clay, and lime kiln dust was placed on top of the clay liner.
Phase n was initiated in August 1994 as a continuation of the non-time critical removal action.
Phase II is scheduled to be completed in July 1995. Work to be completed during Phase n
includes the excavation of 2.5 million cubic yards of waste materials from the CWP, excavation
of 1.5 million cubic yards of material from the BMD, and removal of waste material from the
SDI, and placement of the waste material into the Mine Pits.
Phase m, which incorporates a final cap of the Mine Pits and revegetation of the areas exposed
from the removal of wastes from the CWP, BMD, and SDI will be initiated in 1995, as part of
mis interim remedial action.
1.4.3 Ongoing Actions
At the present time, water collected from the AMD reservoir impounded beneath the CWP, and
the French Drain Sump is currently being treated by the Cropsy Water Treatment Plan
(CWTP). EPA continues to treat water recirculated through the HLP and the French Drain Sump
at the Cyanide Destruct Plant (CDP) and the Metals Removal Plan (MRP).
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EPA is providing the following actions to continue the water treatment operations:
• Maintenance of access roads
Snow removal
• " Site security
1.5 Site Characteristics
1.5.1 Nature and
The EPA (1992) identified the Contaminants of Potential Concern (COPC) based on elevated
concentration and potential toxicity of mobilized chemicals. The COPC will be finalized upon
completion of the Baseline Risk Assessment These concentrations were compared to Site-
specific background levels, which were determined by standard statistical analysis (Morrison
Knudsen Corp., 1994). Potential adverse effects on human health and the environment,
including affected wildlife, were preliminarily assessed (EPA, 1992). The COPC identified for
the Site are copper, cadmium, chromium VI, lead, silver, zinc, arsenic, aluminum, iron, mercury,
manganese, and cyanide.
All of these contaminants, except cyanide, are found at the Site in naturally occurring minerals
and compounds. They are made soluble during the AMD-generating chemical process. The
AMD process is accelerated by the mining activities which took place at the Site.
1.5.1.1 Acid Mine Drainage
At Summitville, mining activities resulted in additional sulfidic material surface area available
for contact with oxygen and water. Air and water contact with the additional surface area
provided by broken rock accelerates oxidation of minerals and creation of low pH drainage. This
drainage water is high in acidity, sulfate (SO4) ions and dissolved metals.
AMD water contributes metal loads to Wightman Fork and Alamosa River. This creates adverse
conditions preventing the growth and maintenance of a healthy aquatic ecosystem. These adverse
effects have been noted in various studies of water quality of Wightman Fork and the Alamosa
River.
1.5.1.2 Water Containing Cyanide
Commercially manufactured sodium cyanide (NaCN) was used at the Site for extracting precious
metals from ore grade materials. Cyanide has been used for this purpose in the mining industry
since the late 1800's. Cyanide is found either in simple form or in combination with other
elements. Simple cyanide forms designated as "free" cyanide are the cyanide radical, CN", and
hydrogen cyanide, HCN. Cyanide also combines or complexes with alkali metal ions, heavy
metal ions, and transition elements. The complex cyanide bonding is very strong, moderately
strong, or weak (defined by tendency to disassociate in an acidic environment). Presence of
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excess hydrogen ions (acid) will lead to the formation of HCN, depending on the-strength of the
metal/cyanide bond.
Cyanide content is found in residual process water contained in the HLP. The predominant form
of cyanide in solution is a Weak Acid Dissociable (WAD) complex (complex that has a
moderately strong bond and dissociates at a pH of 4.5 or greater) with copper. Complexes with
other elements - silver, sulfur, gold, iron and others - are also present Thiocyanate (SCN) is
present hi significant quantities. The thiocyanates may migrate through the water treatment train
into Wightman Fork. The pH of contained residual process water within the HLP averages about
9.3. ,
Leaks in the HLP containment liner result in the presence of cyanide in drainage that surfaces
downgradient of the HLP. These drainage streams from the Valley Center Drain (VCD), and
several seeps in and below HLP Dike 1 are mixtures of residual process water, AMD, and ground
water. The AMD portion results in low pH (2.5 - 3.5), and cyanide exists as either a
metal/cyanide complex (primarily with copper), or as free cyanide (HCN). These streams are
routed to the French Drain Sump to prevent release to Wightman Fork and Alamosa River
drainages. The water is pumped to the HLP and mixed with residual process water, or treated
separately.
1.5.2 Description of Impacted Water
Tables 2-7 summarize data collected during water monitoring before treatment and during
discharge of surface water to Wightman Fork. The tables include recordings of copper and
cyanide loadings from May 1993 through June 1994. During this period, monitoring emphasis
was given to copper and cyanide because these were the chemicals of highest concentration
during the ERRA. There was also a concern because of the potential toxicity of cyanide.
Table 8 shows data representing the copper load (Ibs.) transported by the Site water. The first
group exhibits copper load from water pumped from the French Drain.(FD) Sump. The JD sump
contains water from the VCD and AMD seeps.
The second data group within illustrates the copper concentration of water contained hi the HLP.
This includes water pumped from the FD Sump, water that surfaced at the toe of the CWP, and
process water contained in the HLP. All water hi the HLP is treated to remove cyanide and
copper, as well as other metals, before release to Wightman Fork.
The underground workings section presents data on copper load that was transported by water
exiting from the Reynolds Adit and the Chandler Adit Also shown is the amount of copper
removed through treatment at the Portable Interim Treatment System (PITS). The PITS treated
water exiting the. Reynolds Adit, the Iowa Adit, and some contaminant surface runoff. The plant
was deactivated after the Reynolds Adit plug was completed.
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The remaining sections of the table present the copper content of surface water discharged into
Wightman.Fork during this time period. These include water from Cropsy Creek, seep LPD-2
(which feeds into Cropsy Creek), and Pond P-4 (a sediment pond that receives surface runoff
from the mine pit area, haul roads, and other runoff). Other streams that contributed copper load
to Wightman Fork include drainage from the SDI, the NPWD, the Clay Ore Stockpile, and
treatment plant effluent
Also shown are the pounds of copper that would have been added to Wightman Fork if water had
flowed into Wightman without treatment Annual totals from July 1993 to June 1994 are given
to the right of monthly totals. The twelve month period, July 1993 through June 1994, represents
the time frame when existing treatment facilities utilized maximum capacity.
Table 2 shows monitored cyanide loading (Ibs.) or the potential for cyanide loading to Wightman
Fork during the same period.
Table 3a shows monitored flow rate for streams which are capable of carrying contaminant load
to Wightman Fork. High and low flow rates illustrate seasonal fluctuations. Combined monthly
totals illustrate potentially required treatment volumes.
Table 3b shows the total gallons for streams capable of carrying contaminant load to Wightman
Fork. This table also shows the treatment plant capacity measured in total gallons.
Table 4 shows other monitored constituents (manganese and iron) that should be taken into
consideration in the selection of treatment processes. Manganese removal to <1 mg/liter is
necessary before cyanide destruction can take place. Significant iron content can produce sludge
volumes that affect plant efficiency.
Tables 6 and 7 show copper and cyanide concentrations monitored at station WF 5.5 on
Wightman Fork from May 1993 through June 1994.
General descriptions of monitored surface water affected by conditions at the Site are given
below. Figure 4 shows contaminated surface water streams.
Stream A - The Valley Center Drain (VCD)
General: Comprised of drainage from the CWP, ground water from beneath the HLP,
and leakage from HLP containment Contains cyanide as a result of leakage from the
HLP. CWP drainage contributes low pH and elevated metals.
Volume: Significant flow throughout the year. Peak flow is concurrent with spring
snowmelt High flow (78 gpm)recorded in April 1994; low flow (57 gpm) was recorded
hi June 1993.
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Loading: Based on copper as the indicator, the VCD ranked as the 4th highest peak flow
carrier of metals. 8,473 Ibs. of copper dissolved in solution were transported by drainage
from July 1993 through June 1994.
Stream B - Cropsy Waste Pile Drainage
General: Comprised of ground water flow from seeps and upgradient drainage through
colluvium and alluvium (Geraghty & Miller, 1992). Includes precipitation (snowmelt
and rain fall) infiltrating through mine waste materials. Significant aluminum content
effects must be considered when selecting a treatment process. Volume and makeup are
expected to materially change with planned relocation of C WP
Volume: Seasonal release to the surface at the toe of the CWP. Year round contribution
to the VCD. High flow (364 gpm) recorded in May 1993. Surface flow was not
observed at the toe of the CWP between January - April 1 994.
Loading: Based on copper as the indicator, water surfacing at the toe of the CWP is the
second highest peak carrier of metals. 23,305 Ibs. of copper dissolved in solution were
transported by drainage from July 1 993 through June 1 994 (includes water sent to the
CWTP).
Stream C - Drainage from Underground Workings
General: Comprised of ground water and precipitation (snowmelt and rainfall)
infiltrating the mine pit area. These infiltrating waters draining through mineralized rock .
into the remaining underground workings have historically surfaced as flow from the
Reynolds Adit Comparatively less water volume drains from the Iowa Adit The
Reynolds and Chandler adit; have been plugged. The long-term effects of plugging the
Reynolds Adit in February 1994 and Chandler Adit in March 1994, and the consequent
rise in the South Mountain water table have not been determined. In May 1994, an AMD
stream developed as discharge from the Chandler Adit It has been observed that the
water is flowing between the top of the plug and the roof of the adit (Abel, pers. comm.,
1994). Peak flow from the Chandler Adit leak in June 1994 was 661 gpm with a copper
concentration of 409.40 mg/1 and a pH of 2. 1 6, determined by sampling the stream just
outside the adit entrance. This was almost "instantaneous" (the discharge increased from
0 gpm to 661 gpm in 1 1 days), indicating a direct relationship between the rise in the
South Mountain water table and the filling of the adit system with water. By the end of
July 1994, the flow of the AMD stream decreased to 130 gpm with a copper content of
268 mg/1 and a pH of 2.30. Eventual volume of AMD that may require treatment is
unknown. Corrective measures are planned.
Volume: Significant flow throughout the year. High flow from the Reynolds Adit (763
gpm) was recorded in June 1993; low flow from the Reynolds Adit (6 gpm) was recorded
in April 1994.
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Loading: Based on copper as the indicator, Stream C is ranked as the highest peak flow
carrier of metals. 198,221 pounds of copper dissolved in solution were transported by
drainage from July 1993 through June 1994. Peak: flow of AMD from the underground
workings in June 1994 was 14% less than flow in June 1993. Copper load from
underground workings in June 1994 was approximately 23% less than the load in June
1993. In July 1994 volume from the underground workings was 25% less than in July
1993. Copper load from underground workings in July 1994 was 15% less than in July
1993.
Stream D - Summitville Dam Impoundment and Beaver Mud Dump Drainage •
General: Comprised of the surface drainage into the impoundment and surrounding area
and the ground water migration through the mud dump. Possible ground water migration
through tailings contained in the pond. Includes precipitation (snowmelt and rainfall)
infiltrating through BMD materials. Volume and makeup of this stream is expected to
materially change with planned solid waste relocation in 1994-95 (Cropsy Phase n
operations).
Volume: High flow (202 gpm) was recorded in May 1993; low flow (33 gpm) was
recorded in November 1993. Monitoring was not possible from January 1994 through
April 1994, due to snowpack. • ._
Loading: Based on copper as the indicator, Stream D is ranked as the third highest peak
flow carrier of metals. 12,294 Ibs. of copper dissolved in solution were transported by
drainage from July 1993 through June 1994.
Stream E - North Pit Waste Dump drainage
General: Comprised primarily of surface runoff from waste dump materials. There is
some ground water seepage.
Volume: Significantly varies with precipitation (rainfall and snowmelt). Affected by
spring runoff. High flow (284 gpm) was recorded in May 1993; low flow (1 gpm) was
recorded in October 1993. Monitoring was not possible from November 1993 through
April 1994, due to snowpack.
Loading: Based on copper as the indicator, Stream E is ranked as the 6th highest peak
flow carrier of metals. 4,321 Ibs. of copper dissolved in solution were transported by
drainage from July 1993 through June 1994.
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Stream F - Clav Ore Stockpile Drainage
General: Comprised of surface drainage migration through lower portions of the waste
dump and precipitation (snowmelt and rainfall) infiltrating through upper level materials.
Water migrating from beneath the CWP may also contribute.
Volume: High flow (66 gpm) was recorded in June 1993; low flow (37 gpm) was
recorded in May 1994.
Loading: Based on copper as the indicator, Stream F is ranked as the 8th highest peak
flow carrier of metals. 1,113 Ibs. of copper dissolved in solution were transported by
drainage from My 1993 through June 1994.
Stream G - Sediment pond P-4 drainage
General: Comprised of surface drainage from upgradient disturbed areas. Includes some
contribution from Iowa adit drainage.
Volume: Highly variable, dependent on precipitation events. High flow (948 gpm) was
recorded in May 1994; low flow (4 gpm ) was recorded in November 1993.
Loading: Based on copper as the indicator, Stream G is ranked as the 5th highest peak
flow carrier of metals. 4,508 Ibs. of copper dissolved in solution were transported by
drainage from July 1993 through June 1994.
Stream H - Drainage from Cropsv Creek
General: Comprised of surface drainage from upgradient undisturbed areas. Rerouted
around the CWP and HLP areas during SCMCI operations. Receives some metals
loading from surface runoff from the Cropsy Waste Pile and seep LPD-2, downgradient
from the HLP and Dike 1. May receive loadings from effected ground water. Route does
not go through sediment control features.
Volume: Peak flow is concurrent with spring runoff. Significantly affected by
precipitation (snowmelt and rainfall). High flow was recorded in May 1993; low flow
was recorded in February 1994.
Loading: Based on copper as the indicator, Stream H is ranked as the 7th highest peak
flow carrier of metals. 1,737 Ibs. of copper dissolved in solution were transported by
drainage from July 1993 through June 1994.
The affected stream segments are summarized in the following Table. The streams are ranked in
decreasing order according to the metal load during peak flow.
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Ranking of Surface Water Streams at Peak Row
without Operation of C WIT, CDP and MRP
Metal Load at Peak Flow*
1
2
3
4
5
6
7
8
Stream**
Stream C- Underground Workings Drainage
Stream B- CWP Drainage
Stream D- SDI/BMD Drainage
Stream A- VCD
Stream G- P-4 Drainage
Stream £• NPWD Drainage
Stream H- Cropsy Creek Drainage
Stream F- Clay Ore Stockpile Drainage
*
*»
Rankings are listed in decreasing order.
Table does not include the HLP wastewater stream.
French Drain Sump Inflows
The FD Sump was originally constructed to prevent drainage from the VCD (Stream A) from
entering the Cropsy Creek and Wightman Fork. A collection and pumping facility was installed
after VCD drainage was found to contain cyanide. The sump was also utilized to contain other
contaminated water. These drainages (described below) were found to be contaminated in later
years. Tables 1 - 3b summarize data for copper, cyanide, and water volume for these streams.
General descriptions follow.
FDSump-1 Seepage from Dike 1
General: Comprised of water exiting a point at the base of Dike 1.
Volume: Peak volume (1,785,600 gal., June 1993) is concurrent with spring snowmelt
Loading: At peak flow, Stream FD Sump-1 transports up to 83 Ibs of copper per day.
Load declines to less than 3 Ibs per day as flow decreases.
FD Sump -2 Seepage from the Dike 1 ramp
General: Comprised of water exiting a point on the access road that flanks Dike 1.
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Volume: Peak volume (820,000 gal. in June 1993) is concurrent with spring snowmelt
Flow ceases soon after the peak snowmelt period. Water is acidic, and contains cyanide.
Loading: At peak flow, Stream FD Sump-2 transports up to 5.7 Ibs of copper per day.
Load declines to less than 1 Ib. per day as flow decreases. - •- .
FDSump-3 Drainage from beneath the HLP
General: Comprised of water exiting rock drains built to divert water during HLP
construction at 1 1,510 and 1 1,530 elevations. Discharges are combined and routed to the
FD Sump. There is a wide range in copper content Contains a slight amount (0.12 mg/1)
of cyanide at peak volume discharge. ____ ............ ,.......•
Volume: Peak volume (1,1 16,000 gal. in June, 1993) is concurrent with spring
snowmelt Significant flow continues throughout the year.
Loading: At peak flow, Stream FD Sump-3 transports up to 27 Ibs of copper per day.
Load declines to less than 1 Ib. per day as flow decreases.
j.5.3 C9nt3niTnaTlt Tranmnr| and Migration
1.5.3.1 Surface Water
Surface water is considered the most significant media for off-site transport of metals. Surface
water has been impacted by mining operations from the Site throughout the reach of Wightman
Fork, from the Site to the Alamosa River, and within the Alamosa River from 'Wightman Fork to
Terrace Reservoir and points further downstream. According to the Conceptual Sitewide
Remediation Plan prepared for the EPA, it has been determined that the Site is the predominant
source of metals loading to the Alamosa River system.
As pH of water rises from the addition of water with higher pH, iron precipitates from solution as
a hydrated iron (HI) oxide product (ferric hydroxide). This forms the red or yellow staining seen
on rocks in the streams or on banks. Copper, cadmium and zinc will co-precipitate with iron
precipitates. Metals concentrations are further reduced by dilution from downstream tributaries.
COPC could be biologically transported through an aquatic food ehaii^ and could be transported
to birds, animals and humans. The Baseline Risk Assessment (BRA) has not been completed;
however, qualitative risk analysis has been performed by EPA which verifies this data (ERT,
1993). The BRA is scheduled for completion in 1995. Currently, the full range of COPCs is
being reassessed and additional contaminants of concern (COC) may be identified in the BRA.
1.5.3.2 Ground -water
Ground water depths vary at the Site. In general, water levels are relatively close to the surface
except in the vicinity of the old mine workings where depth to water can be as much as 300 feet
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The old workings act as effective underdrains. Ground water and precipitation infiltrating
through the Mine Pits pass through mineralized rock and into the underground workings. This
water has historically surfaced as AMD at the Reynolds Adit It is anticipated that the ground
water level will rise as water backs up behind the plugged Reynolds and Chandler Adits.
The ground water occurs hi surficial deposits consisting of colluvium, alluvium, and/or glacial
moraine; and fractured andesite of the Summitville Formation. Ground-water flow is within the
weathered and fractured bedrock and, within alluvium near the Cropsy Creek and Wightman
Fork channels. Ground-water flow and metals are capable of being transmitted to Wightman
Fork through the alluvial and bedrock systems. Ground water is generally shallow (02 to 25 feet
within the alluvium) and flows northeast in both the Cropsy and Wightman Fork drainages. The
CWP and HMD were placed on springs and seeps in these drainages.
This underground flow is the primary source of water that generates AMD from the CWP and
BMD.
Shallow ground water at the Site is present as a series of intermittent, perched systems. The
perched aquifer system contributes to recharge of the shallow fractured bedrock system. No
regional ground-water table has been identified at the Site. The ground water close to the surface
is strongly influenced by precipitation. During spring runoff, these shallow systems discharge to
surface water. Numerous springs and seeps are evident throughout the Site and most flow hi
direct response to precipitation.
1.5.3.3 Soil and Air
Site cover consists of topsoil, silt, clays, and gravel. The topsoil is described as
grey/brown/orange, non-plastic with a trace of roots and sand. The clays are low to medium
plasticity with some gravel. The gravel is indicative of colluvial deposits or tailings. The
disruption of the surface soils may be a secondary source of excess metals migration.
1.5.4 ARARs
ARARs are "applicable" or "relevant and appropriate" requirements of federal or state law which
address a hazardous substance, pollutant, contaminant, remedial action, location or other
circumstance found at a CERCLA Site. Refer to Table 7 for a detailed summary and discussion
of ARARs. The NCP defines "applicable" requirements as cleanup standards, standards of
control, and other substantive environmental protection requirements, criteria, or limitations
promulgated under Federal or State law that specifically address a hazardous substance,
pollutant, contaminant, remedial action location or other circumstance found at a CERCLA site.
"Relevant and appropriate" requirements address problems or situations sufficiently similar to
those encountered at the CERCLA site that then* use is well suited to the environmental or
technical factors at a particular site. (See 40 CFR Section 300.5.)
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ARARs are grouped into three categories:
• Chemical Specific
4 Action Specific
• Location Specific
Chemical specific ARARs include health or risk based narrative standards, numerical values, or
methodologies that, when applied to site-specific conditions establish the acceptable amount or
concentration of a chemical that may remain or can be released to the environment Action
specific ARARs are usually technology or activity-based requirements or limitations on actions
taken with respect to hazardous substances found at CERCLA sites. Location specific ARARs
are restrictions placed on the concentration of hazardous substances or the conduct of activities
solely because they occur in special locations. Examples of special locations include fioodplains,
wetlands, historic places and sensitive ecosystems or habitats. (See "CERCLA Compliance with
Other Laws Manual Draft Guidance," EPA/540/G-89/006 August 1988.) .
In addition, the NCP has identified a fourth category of information "to be considered" when
evaluating remedial alternatives, known as TBC. TBC represent Federal and State advisories,
criteria or guidance that are not ARARs, but are useful in developing CERCLA remedies. (See
40CFR300.430(g)(3).)
The analysis of ARARs has been limited to the scope of the interim action. The NCP allows
waiver of ARARs for interim remedial measures that do not exacerbate site problems or interfere
with final remedy (40 CFR 300.430(f)(l)(ii)(C)(l) and 55 FR 8747). Other ARARs may be
involved in enacting final remedy(ies).
The sitewide ARARs were identified in the addendum to the HLP FFSs. However, in response
to comments submitted during the public participation process on the CWP FFS and Proposed
Plan, EPA is further defining the ARARs from Federal and State laws or regulations which must
be met by any alternative implemented as the CWP interim remedial-action; Since the sitewide
ARARs have already been identified in the " ARARs Addendum to the HLP Focused Feasibility
Study Report", this further refinement of ARARs as they relate to the CWP IROD represents
only a minor change to the CWP FFS and Proposed Plan. Consistent with its "Interim Final
Guidance on Preparing Superfund Decision Documents", OSWER Directive 9355.3-02 (June
1989), EPA has determined that this minor change will have little or no impact on the overall
scope, performance, or cost of each alternative as originally presented in the CWP FFS or
Proposed Plan.
The following sitewide ARARs, or relevant portions of the sitewide ARARs, must be met in
accordance with Section 12 l(e) of CERCLA and 40 C.FJL 300.430 of the NCP by each
potential CWP interim remedial action alternative:
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1.5.4.1 Chemical Specific ARARs
Surface Water ARARs
The Colorado Water Quality Standards (CWQS) establish a system for classifying state surface
waters and procedures and criteria for assigning numeric water quality standards. (See 5 CCR
1002-8, Sections 3.1.0 through 3.1.17.)
o Colorado Water Quality Standards, Applicable
Criteria for Stream Classification
The CWQS require that surface waters be:
classified for the present beneficial uses of the water, or the beneficial uses mat
may be reasonably expected in the future for which the water is suitable in hs
present condition or the beneficial uses for which it is to become suitable as a
goal— Where the use classification is based upon a future use for which the
waters are to become suitable, the numeric standards assigned to such waters to
protect the use classification may require a temporary modification to the
underlying numeric standard... (See §3.1.6.)
The CWQS employ four broad types of beneficial use to frame the classification process:
• recreational
• aquatic life
• agriculture
• domestic water supply .
Recreational Use
The recreational uses are divided into two classifications. Recreational Use, Class 1 -
Primary Contact, addresses surface water quality concerns where ingestion of small
quantities of water during the use is likely to occur. Recreational Use, Class 2 -
Secondary Contact, focuses on streamside activities where ingestion of water is unlikely
to occur. The effect of the recreation classification on numeric water quality criteria is <
limitprf the primary consideration being the concentration of fecal colifbnn bacteria. The
Summitville Minesite is unlikely to contribute bacterial contamination to the watershed.
For mat reason, the recreational use classifications will not be considered further.
Aquatic Life
Two aquatic life classifications are currently promulgated for stream segments of interest.
Class 1 cold water aquatic life is defined as: .
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...waters thai (1) currently are capable of sustaining a wide variety of cold
water biota, including sensitive species, or (2) could sustain such biota but
for correctable water quality conditions. Waters shall be considered
capable of sustaining such biota where physical habitat; water flows or
levels , a"d water quality conditions result in no substantial impairment of
the abundance and diversity of species. (See §3.1.13(l)(c)(i).)
Class 2 cold and warm water aquatic life is defined as:
...waters that are not capable of sustaining a wide variety of cold or warm
water biota, including sensitive species, due to physical habitat, water
flows or levels, or uncorrectable water quality conditions that result in
substantial impairment of the abundance and diversity of species. (See
Domestic Water Supply
Domestic water supply is defined as: ...''_.
...suitable or intended to become suitable for potable water supplies. After
receiving standard treatment ... these waters will meet Colorado drinking
water regulations... (See §3.1.13(1 )(d), emphasis added.)
Agricultural Use
Agricultural use is defined as:
...suitable or intended to become suitable for irrigation of crops usually
grown in Colorado and which are not hazardous as drinking water for
livestock... (See §3.1.13(l)(b).)
• I
Three segments of the Alamosa River are classified for various uses according to mis system:
Si* c^ent 6, the Wightman Fork at and below the mine; Segment 3b, the Alamosa River from
k_nediately above the confluence with Wightman Fork to Terrace Reservoir; and Segment 8,
Terrace Reservoir. Figure 5 shows segments of the Alamosa River Basin.
Segment 6 is classified for Class 2 and Agriculture. It is not classified for aquatic life. No
numeric water quality standards have been assigned. The lack of an aquatic life classification
was derived by the use attainability analysis performed by the Colorado Water Quality Control
Commission (WQCC). The WQCC determined that an aquatic life classification cannot be
attained within 20 years.
Segment 3b is classified as Class 1 Cold Water Aquatic Life. Numeric Standards are set for
surface water downstream of the confluence of Wightman Fork and the Alamosa River.
28.
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Terrace Reservoir is classified as Class 2 Cold Water Aquatic Life. This classification
recognizes a limit on the ability of Terrace Reservoir to sustain a diverse aquatic community.
Standards
The CWQS provides a three-tiered structure for establishing numeric water quality standards.
For unimpacted high quality waters, numeric levels known as the Table Value Standards"
(TVS) are established and presumed to be protective. For impacted waters where pollutant
concentrations exceed TVS values but the beneficial uses are adequately protected, Ambient
Quality-Based Standards can be adopted. For impacted waters where beneficial uses are not
currently adequately protected, TVS are adopted as a goal. Temporary modifications to numeric
standards may be adopted in these areas. Where classified uses are not being protected and a use
attainability analysis hag found nonattainability, Site-Specific-Criteria-Based Standards e*»ri be
developed. The TVS and Ambient Quality-Based Standards are applicable regulations for
determining compliance with surface water discharges at the Site. Segment 3b of the Alamosa
River is downstream of the Site at the confluence of the Wightman Fork and the Alamosa River.
These regulations were used to establish promulgated standards in this segment of the Alamosa
River. Specifically, the Classifications and Numeric Standards for Rio Grande Basin are found
in Section 3.6.6. of the regulation. Table 8 illustrates these levels. These standards are
categorized into acute and chronic limits. Acute limits represent an upper level not to be
exceeded in any 24 hour period. Chronic standards are average levels which can not be exceeded
in a 30 day period. '~.'"'
Table Value Standards
The TVS are based upon the Federal Water Quality Criteria. The TVS, however, have been
adjusted to protect the beneficial uses of Colorado waters (See §3.1.7(b)(i).) The TVS for
aluminum (acute), arsenic (acute), 'lead (acute/chronic), nickel (acute/chronic), selenium
(acute/chronic), silver (acute/chronic), *?nc (acute/chronic), chromium VI (acute/chronic),
chromium. DI (acute), mercury (chronic), manganese (chronic), cadmium (acute/chronic), pH,
dissolved oxygen, Fecal Coli, ammonia, chlorine, sulfide, boron; nitrate and cyanide are set at
Segment 3b. It is important to note mat many of the TVS for protection of aquatic life from
metal pollutants are harrmegg dependent. The WQCC has adopted an acute and a chronic copper
standard for Segment 3b. The acute copper standard for Segment 3b is established using the "
TVS; however, the WQCC has adopted a less stringent temporary modification to this standard
based upon WQCC hearing testimony. The EPA has adopted and will meet the ambient quality
based chronic copper standard as applicable for mis interim action and is not using the less
stringent acute copper standards from the TVS or the less stringent August 1 994 temporary
modification. The IAL, as monitored at WF-5.5, were developed to meet the more stringent
ambient quality-based chronic copper standard at Segment 3b.
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Ambient Quality-based Standards
Ambient quality-based numeric surface water quality standards are the mechanism where limited
water quality impacts are controlled through less stringent water quality standards. Ambient
quality-based standards are specifically intended to address circumstances where natural or
sible man-induced ambient water quality levels are higher than the specific numeric levels
icrcvciai
contained in the TVS Tables I, n, and HI, but are determined "adequate to protect classified
uses." (See §3.1.7(l)(b)(ii).) The chronic standard for copper is established at Segment 3b using
this regulation. Copper is one of the primary contaminants of concern for water quality. The
chronic copper standard was used as the most strict ARAR for copper at the Site. The lALs were
developed u-sipg this standard. The chronic standard for iron also falls into1 ambient water quality
standards. There are no acute iron standards.
To evaluate the ability of alternatives to meet the stream classification and numerical standard of
the CWQS ARARs, EPA established interim action levels (IAL) for water quality. These IAL
can be found at page 23 of the Water Treatment FFS. The IAL are developed using a model
which utilized high flow and low flow average concentration^ of the contaminants to set
threshold loadings allowable at Wightman Fork monitoring point 5.5. Numerical standards mat
would enable the river water quality to meet the water quality ARAR at Segment 3b under
average conditions were then calculated. Based upon theWQCC numeric water quality
standards for Segment 3b, the TVS levels were used for all COPC at the Site with the exception
of copper and iron. EPA used the WQCC ambient quality standard for copper and iron. The
ambient level for copper is 30 ug/1 based upon the 85th percentile ambient data in Segment 3a.
The methodology used to develop these levels is similar to the criteria applied in the
development of the Numeric Criteria Levels (NCL), that is, back modeling the contaminant
loading from the promulgated ARARs at the Alamosa River. These IAL are formally adopted as
remedial goals in the IRODs.
The discharge monitoring point, WF-5J, is the interim monitoring point for the Site, and the
IAL are the interim water quality standards during this remedial action five year period. It is
important to note that the lALs are not "interim" due to their inability meet ARARs; rather, EPA
believes thaf these ARAR-derived limits at the point of compliance do g**ai" the numerical
standards at Segment 3b. The ability of the IAL to achieve the applicable water quality
standards, however, will be reassessed by EPA upon the completion of the quantified Risk
Assessment and the State of Colorado use-attainability study. The results of these efforts will be
incorporated into a final remedy.
o Federal Water Quality Criteria, Applicable
The preamble to the proposed NCP states:
(a) State numerical WQS is essentially a site-specific adaptation of a Federal
Water Quality Criteria (FWQC), subject to EPA approval, and, when available, is
generally the appropriate standard for the specific body of water." (See 53 FR
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51442, right column, top.)
As noted above, the FWQC would only be applicable in the absence of current, segment specific
CWQS. In this circumstance, current, segment specific CWQS are available and will be applied
as the surface water quality ARARs for the Site. The FWQC are considered applicable since this
ARAR establishes me basis for tne State of Colorado's numerical standards. .
Ground Water ARARs
The Colorado Ground Water Standards (CGWSs) provide for identification of specified ground
water areas, classification of the specified areas, and numeric ground water quality standards.
5 CCR 1002-8 establishes a system for classifying ground water and adjusting water quality
standards to protect existing and potential beneficial uses. The ground water classifications are
applied to "specified areas," a concept identified in the definitions and explained in Section
3.1 1.4(C)(1). Those ground waters not classified as within "specified areas" may be subject to
Statewide radioactive material standards listed in Section 3.1 1.5(C)(2) of the Basic Standards of
Ground Water, 3.11.0 (5 CCR 1002-8) and organic standards identified in Table A. of Section
Since the Colorado Water Quality Commission has yet to classify the Site as a "specified area,"
there are no currently applicable or relevant and appropriate Colorado Ground Water numeric
standards for the Site. However, since the publication of the WTFFS, the Colorado Water
Quality Control Commission b^s adopted an interim narrative standard for all unclassified
ground waters of the State that supplements the Statewide standards for radioactive matgrjajg and
organic pollutants established in Section 3.1 1-5(C) of the Basic Standards for Ground Water.
This narrative standard requires that ground water quality be maintained for each parameter at
whichever of the following levels is less restrictive:
(i) existing ambient water quality as of January 31, 1994, or
(ii) mat quality which meets the most stringent criteria set forth in Tables 1
through 4 of "The Basic Standards for Ground Water."
Ambient water quality is established by agencies "with authority to implement this standard"
using "their best professional judgment as to what constitutes adequate information to Heiwmine
or estimate existing ambient quality, talcing into account the location, sampling date, and quality
of all data available" prior to January 31, 1994. Based on Rule 1, Section 1.1(5) of the Mineral
Rules and Regulations, EPA believes the Mined Land Reclamation Board is the agency that has
me primary authority to implement the narrative standard for ground water at the Summirville
Site. MLRB and WQCD established Numeric Criteria Levels for surface and ground water
quality at the Summitville Site in SCMCTs operating permit, as well as its 1991 Settlement
Agreement between SCMCI and the State of Colorado. These NCLs are not applicable or
31
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relevant and appropriate, since they are not legally binding, promulgated regulations. However,
these standards have been considered by EPA in establishing its interim action levels for water
quality because they provide useful information or recommended procedures in addressing the
interconnected ground water and surface water at the Site.
This interim ground water narrative standard, since it became effective on August 30,1994, was
not identified as an ARAR in any of the FFSs for the Site. However, since compliance with mis
ground water ARAR will have tittle or no impact on the overall scope, performance or cost of the
alternatives evaluated, inclusion of this ARAR represents only a minor change to the FFS and
Proposed Plan. See "Interim Final Guidance on Preparing Superfund Decision Documents,"
OSWER Directive 93553-02 (June 1989), at p. 5-3.
EPA further expects that once the CWQC completes its use attainability study and classifies Site
ground water, the interim narrative ground water standard will be replaced by a "specified area"
classification or "site-specific" standard for the Site. This ground water ARAR will be attained
by the final remedial action^) forme Site.
Storm Water Management and Effluent Limitations ARARs
Storm water management is governed by the storm water permitting requirements and the
Categorical Standards for Ore Mining and Dressing. Both the storm water permitting program
and the categorical standards are as applied pursuant to the Colorado Discharge Permit System.
Requirements are collection and treatment of storm waters using the Best Available Technology
(BAT) for those storm waters which contact mine waste. In addition, bom regulatory programs
require implementation of Site-specific Best Management Practices (BMP). The BMP
emphasize storm water diversion and land/soil reclamation to mtmtnfag the contact of storm
water with mine wastes.
o Copper, Lead, Zinc, Gold, Silver and Molybdenum Ores Subcategory Effluent
Limitations, Relevant and Appropriate
This ARAR applies to "process waste waters" only. Process waters are defined in 40 CFR
401.11(q)as:
"any waters which, during m«ri"i?e*"""g or processing, comes into direct contact
with or results from the production of any raw material, intermediate product,
finished product, by-product, or waste product"
The effluent limitations found in 40 CFR 440.103 would be appropriate and relevant to the
Water Treatment FFS activities but not applicable because the discharges are not "process waste
waters." The IAL established by EPA to meet me surface water quaUtyARARs are
stringent than these categorical effluent limitations.
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o Colorado Discharge Permit System Regulations/Federal Storm Water Permitting
Requirements
Colorado's authority to require permits for the discharge of pollutants from any point source into
waters of the state are derived from the Federal National Pollutant Discharge Elimination System
(NPDES) regulations. (See 40 CFR Part 122.) Colorado's NPDES based program can be found
in the Colorado Discharge Permit System Regulations (CDPSR). The WQCC Division Permit
issued for the treatment plant at the Site (CDP #CO-0041947), dated November 12,1991, is the
CDPSR document for the Site. Additional permit modification activities are documented in the
July 1991 Settlement Agreement and the July 1992 Amendment to the Settlement Agreement
Storm water is defined in NPDES program as "storm water runoff, surface runoff, snow melt
runoff, and surface nmoff and drainage". (See 40 CFR 12226(b)( 13).) A permit application is
required for active and inactive mining sites where an owner can be identified and when
discharges of storm water runoff from mining operations come into contact with any overburden,
raw material t intermediate product, finished product, by product, waste product or areas where
tailing have been removed. (See 122-26(b)(14)(ffi).) As such, the substantive NPDES Storm
Water permit requirements are applicable to discemable surface flows of storm water mat
contacts waste rock, the crushed ore currently contained in the heap leach pads, wet waste rock
(miiffy clay ore, nr tailings at the Siimmitville Minesite. Infiltration is not covered by this
program, (See 55 FR 47996, left column, center.)
The storm water permit regulations require compliance with Sections 301 and 402 of the Clean
Water Act Sections 301 and 402 require use of BAT to control toxic pollutants, and where
necessary, further control to achieve ambient water quality criteria. In addition, the storm water
regulations require implementation of stormwater BMP as part of the comprehensive program.
EPA has established effluent limitation guidelines for storm water discharges from the Ore
Mining and Dressing category. These effluent limits require application of BAT to the Ore
Mining and Dressing category • In those regulations, EPA nag defined "mine" broadly and a in
manner which coincides with the definition provided in the Storm Water Permit requirements.
(See 40 CFR 440.132(g).) The effluent limitation guidelines for Ore Mining and Dressing also
provide an exemption for overflow of excess storm water caused by a greater than a 10 year 24
hour precipitation event when a facility has met certain design and operational prerequisites.
This exemption remains in effect as part of the new independent storm water permitting program.
(See 55 FR 48032, right column, bottom.)
Both the effluent limits and the storm water permitting program require application of BAT and,
if necessary, additional controls to meet ambient water quality standards. In addition, both
programs require implementation of stormwater BMP. The only jurisdicn'onal distinction is that
the Ore Mining and Dressing Category effluent limits are not applicable, but instead relevant and
appropriate. The recognition by the storm water permit program of the overflow exemption
demonstrates the existing equivalence of the programs. Thus, attainment of the Effhi
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Guidelines and Standards for Ore Mining and Dressing will ensure attainment of the storm water
discharge requirements.
Eight outfalls were identified at the Summitville Mine site which meet the point source discharge
requirement for storm water permitting. The discharge from each of these outfalls have been
attributed to one of the three categories of precipitation related discharges defined by the storm
water regulations. (See 40 C J JL 12Z26(b)(13); 55 Federal Register at 48065.)
Pursuant to the NPDES Storm Water Permitting requirements and in response to obligations
under the July 1, 199 1 Settlement Agreement and Compliance Plan (the Compliance Plan) for
Summitville Mine, a two volume Best Management Practices (BMP) plan dated October 3 1,
1 991 was developed. The Compliance Plan required mat the BMP provide a reclamation plan
and implementation schedule that included existing and planned pollution prevention practices.
The BMP also evaluated the need for long term treatment of storm water drainage at the facility.
The BMP was designed to mirrimiye or control contact between precipitation and potential
sources of pollutants. The BMP developed at the Summitville Minesite included housekeeping,
employee training, inspections, preventative maintenance. In addition, reclamation activities
such as grading, stabilization, revegetation, erosion control and sediment control were included
as part of the BMP. Each of the measures was designed to protect the existing water quality and
quantity during the operation phase and upon closure of the Summitville Mine.
The existing BMP plan which is currently being implemented at the Site and will continue to be
implemented regardless of which alternative is selected, attains compliance with the NPDES
stonnwater and categorical point source standards.
1.5.4.2 Action Specific ARARs
RCRA Subtitle C
40 CFR 26 1 .400(7) specifically excludes "solid waste from the extraction, beneficiation, and
processing of ores and minerals..." from the rules governing management of hazardous waste in
Resource Conservation and Recovery Act (RCRA) Subtitle C. Mine wastes present at the
Summitville Minesite, including waste rock, the crushed ore currently contained in the heap
leach pads, wet waste rock (mud), clay ore, and tailings, were generated as a result of the
extraction, processing, or beneficiation of ores and minerals. Accordingly, RCRA Subtitle C is
not applicable to the remediation of this mine waste.
RCRA Subtitle C may be relevant and appropriate to actions at the Summitville Minesite if the
mine waste material;? are sufficiently similar to RCRA hazardous waste, particularly if the
subject wastes fail the Toxichy Characteristics Leachibility Procedure (TCLP) or exhibit other
characteristics of RCRA hazardous wastes (e.g., low pH). (See "Superfund Guide to RCRA
Management Requirements for Mineral Processing Wastes, 2nd Edition," OERR Directive
9347 Ja-12 (August 1991).)
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Further, if the disposal activity involves the use of a waste management unit sufficiently similar
to a RCRA regulated unit, and the unit is to receive wastes sufficiently similar to RCRA
hazardous wastes, the RCRA Subtitle C requirements pertaining to that type of waste
management unit would be relevant and appropriate. (See 55 FR 87630.)
The EPA has stated, when describing its overall liquids management strategy for RCRA Subtitle
C land disposal units:
as described in the preamble to the minimum technology regulations (47 FR
32274, July 26,1982 and 51 FR 10706, March 28,1986), the Agency's general
strategy for such units is to impose design and operation requirements to :
minimize l^a^hatg generation (e.g. caps and prohibition on liquids in landfill) and
then to require removal of the leachate before liquids migrate into the
environment (See 52 FR 8712.)
Given the acid and contaminated leacfaate generating potential of the materials found at the
C WP, HMD, SDI and Mine Pits portions of the Site, EPA determined that the wastes are
sufficiently similar to hazardous wastes to warrant imposition of selected portions of RCRA
Subtitle C requirements. The Subpart L Waste Pile closure requirements, Subpart K Surface
Impoundment closure requirements, and Subpart N Landfill closure requirements are therefore
relevant and appropriate to the closure of the CWP, BMD, SDI and Mine Pits. Accordingly,
following placement of the materials in the Mine Pits, the unit must be closed in a manner that
attains the following relevant and appropriate requirements:
+ provision of a low maintenance cover that minimises migration of liquids
through the closed unit; promotes effective drainage; minimi-^ cover
erosion; and is capable of accommodating settling and subsidence (see 40
CFR 264.310(a), 264.228(a), 264.258(b)); and
• provision for long term maintenance of the cover, continued operation of the
leachate collection system and continued control of runon and runoff (40 CFR
264.310(b), 264.228(b), 264.258(b).)
Colorado Mined Land Reclamation Act
The Colorado Mined Land Reclamation (MLR) regulations at 2 CCR 407-1 require the
reclamation of mined areas. The MLR regulations provide specific reclamation criteria which
are applicable to the Summitville Minesite. In particular, Rule 3 of the Mineral Rules and
Regulations of the Colorado Mined Land Reclamation Board is applicable to the remedial action
being implemented at the CWP. The remedial alternatives must attain the requirements for
reclamation measures and the reclamation performance standards found in §§ 3.1.5 (Reclamation
Measures - Materials Handling), 3.1.9 (Topsoiling), and 3.1.10 (Revegetation). The general
water (§3.1.6), ground water (§3.1.7), wildlife (§3.1.8) and building and structures (§3.1.11)
requirements, while also applicable to the CWP interim remedial action, will be met with the
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attainment of other federal or state ARARs which provide more stringent standards for the same
subject matters.
The conditions imposed by the Colorado MLR Permit #M-84-157 for the Summitville Mine
stipulated a phased approach to land reclamation which minimizes the total disturbed area at any
point in time. When mining activities in each area have been completed and the sections are no
longer needed, the permit requires that all land associated with waste dumps, leach heaps, roads,
mine pits and plant facilities be reclaimed for forage and timber use. Reclamation activities at
the Summitville Minesite will emphasize surface soil stabilization (to include grading, top soil
management, and revegetation), preservation of water quantity and quality, and concern for the
safety and protection of wildlife.
The reclamation requirements of the MLR are ARARs, not the site specific MLR reclamation
plan. Regardless, the existing MLR reclamation plan does represent the site specific application
of the MLRs, and is, therefore, TBC from an ARAR perspective.
Clean Air Act
Federal and state ARARs were identified for construction and generation of paniculate matter
(PM10) at the Site. An emission permit will be required if temporary construction activities
exceed more than two years (See 5 CCR1001, §3(T)(B)(3)(e).) Control measures to minimise
dust and air monitoring will be implemented if necessary during remedial construction activities.
Regulation i of the Colorado Air Pollution Control Regulations requires all sources of particulate
emissions to utilize technically feasible and economically reasonable control measures. This
requirement is applicable to remedial activities that produce fugitive particulate emissions at the
Site.
An air pollution permit was applied for at Summitville Minesite for the emission of hydrogen
cyanide as a stationary source. The permit included a description of the cyanide heap leach pad
process at the Summitville Mine and all associated process chemistry. Permit # 92-RG-653 was
given an exempt status in September of 1992. The Summitville Site claimed uncontrolled
emissions of less than one ton per year and no emissions of hazardous, odorous or toxic
pollutants and was therefore exempt (see 5 CCR Section 3(II)(C)(l)(j).) Thus, this particular
requirement is not applicable or relevant and appropriate at the Site.
1.5.4.3 Location Specific ARARs
National Historical Preservation Act
The National Historic Preservation Act (NHPA) requires federal agencies to account for the
effects of any federally assisted undertaking on districts, sites, buildings, structures of objects
that are included on the National Register of Historic Places. Executive Order 11593 also
requires consideration of the cultural environment Similarly, the Colorado Register of Historic
Places establishes requirements for protection of properties of state historical interest In
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addition, the Historic and Archeological Data Preservation Act of 1974 establishes procedures to
preserve historical and archeological data which might be destroyed through alteration of terrain
as a result of federal construction projects.
At the Summitville Minesite, an inventory of historic, cultural and archeological resources will
be performed. This inventory will serve to identify cultural and historic resources that must be
considered during the development, analysis, selection and implementation of a remedy. In
addition, the inventory will identify historic and cultural resources that are candidates for
inclusion on either the state or national historic registers.
Endangered Species
The Endangered Species Act requires that federal agencies ensure that federal actions will not
jeopardize the continued existence of any threatened or endangered species or impact critical
habitat In response, a Preliminary Natural Resource Survey will be performed to identify
natural resources, habitat types, endangered or threatened species, and any potential adverse
effects or injury to trust resources.
Protection ofFloodplains and Wetlands
Executive Order No. 11988 and Executive Order No. 11990 require federal agencies to evaluate
the potential adverse effects of proposed actions on Floodplains and Wetlands, respectively.
Floodplains and wetlands potentially subject to adverse impacts from site remedial actions will
be inventoried and considered during the analysis, selection, and implementation of the remedy.
Clean Water Act—Dredge and Fill Requirements.
Section 404 of the Clean Water Act prohibits the discharge of dredged or fill material into
navigable waters, including wetlands. The Section 404 requirements are applicable if any
remedial action construction will involve dredge and fill activities.
Fish and Wildlife Coordination Act
The Fish and Wildlife Coordination Act serves to protect fish and wildlife when federal actions
result in the control or structural modification to natural streams or water bodies. Federal
agencies must develop measures to prevent, mitigate, or compensate for project related losses of
fish and wildlife. Specifically included are projects involving stream relocation and water
diversion structures. If applicable, prior to modification of water bodies, the applicable
regulations will be followed.
Colorado Wildlife Act
The act establishes the Colorado Wildlife Commission, provides for wildlife management, and
prohibits actions detrimental to wildlife. The act is applicable if wildlife observed at the Site
would be adversely impacted by the implementation of the remedial action.
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Wildlife Commission Regulations • .
Chapter 10 of the Colorado Wildlife Commission regulations 92 CCR 406-8, Chapter 100
designates and protects certain endangered or threatened species. The regulations are applicable
if endangered or threatened species observed at the Site are adversely impacted by the
implementation of the remedial action.
Floodplain Management
The Executive Order on Floodplain Management (No. 11988) and 40 CFR §6.302(b) and
Appendix A requires federal agencies to evaluate the potential effects of actions they may take in
a floodplain and to avoid, to the maximum extent possible, any adverse impacts associated with
direct and indirect development in a floodplain. This requirement may be applicable if the
remedial activities take place in a floodplain.
Wetlands Protection
Executive Order on Protection of Wetlands (No. 11990) and 40 CFR §6.302(b) and Appendix A
require federal agencies to evaluate the potential effects of actions they may take in wetlands, in
order to minimize adverse impacts to wetlands. This requirement is applicable if the remedial
activities take place in wetlands.
1.6 Summary of Site Risks .
The Human Health and Ecological Risk Assessment for the FFS was conducted using relevant
EPA guidance including the Risk Assessment Guidance for Superrund (EPA, 1989)and the
RCRA Facility Investigation (RFI) Guidance (EPA, 1989). This risk assessment was a screening
level risk assessment intended to briefly examine risks associated with the HLP.
1.6.1 Screening Ecological Risk Assessment
A Screening Ecological Risk Assessment for the Summitville Minesite was prepared by EPA in
April, 1993. The screening ecological risk assessment reviewed the no action alternative to
determine if there is an imminent hazard to the Wightman Fork from the site. .Copper, zinc, and
cyanide were chosen as the COPC for the assessment
The assessment modelled, measured, and predicted concentrations and loading of copper in
Wightman Fork for three scenarios:
April 1993 conditions (included treatment of HLP contained water and discharge
from the Reynolds Adit);
• Cessation of water treatment activities; and
• Catastrophic release of water contained in the HLP that could result from an event
such a failure of Dike 1, the downgradient impoundment feature.
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Effects of the contaminants on rainbow trout and brook trout were estimated by correlating acute
toxicity levels of the contaminants with measured and predicted concentrations. The degree of
metals toxicity for aquatic life as affected by the pH and hardness of water was described. Study
results of copper concentrations that are toxic to trout at differing water hardnesses were included
in the assessment to illustrate the variation of toxic copper concentrations with water hardness
(the sum of calcium and magnesium concentration expressed in terms of equivalent calcium carb
Continuation of Site water treatment prior to discharge and decrease of loading of
metals into the stream to State of Colorado NPDES permit levels;
• Reduction of the flow of contaminated ground water through plugging the adits
for long-term metal loading reductions to the Wightman Fork;
• Conducting an ecological survey of Wightman Fork to obtain Site specific
information to document actual discharge impacts and document recovery of
Wightman Fork after remediation; and
• Completion of a baseline risk assessment because the review of the no action
alternative produced an unacceptable risk, defined as exceeding the Low
Observed Adverse Effect Level (LOAEL).
The screening ecological risk assessment predicts an imminent hazard to the environment and
suggests that all appropriate response actions should be undertaken to prevent the adverse effects
from continuing to take place. The remedial actions are intended to stabilize specific portions of
the site, prevent further environmental degradation, and achieve significant risk reduction.
1.6.2 Environmental Risk Assessment
/.6.2.1 Aquatic Receptors
In general, the potential risks to aquatic organisms posed by an untreated release from the French
Drain are predicted to be immediate and pronounced.. Chemicals of potential concern in the
French Drain exceed acute and chronic surface water goals by several orders of magnitude.
Modelling predicts that concentrations of cyanide discharging from Cropsy Creek remain acutely
toxic until the confluence of the Wightman Fork with the Alamosa River. Furthermore, the
concentrations of cyanide would remain at levels in excess of the Colorado TVS in the Alamosa
River for some distance below Wightman Fork. The TVS are promulgated, risk based standards
developed to protect aquatic life uses.
It is important to note that the Site's impact on pH alone may contribute to toxicity to aquatic
organisms, as there is a limited range of pH levels tolerated by aquatic receptors.
Prior to treatment of the Chandler Adit, the Colorado TVSs, ARARs in Segment 3b of the
Alamosa River, were regularly exceeded for copper, zinc, aluminum, iron and manganese. These
exceedences are especially problematic as the hardness-dependent Colorado TVS may
underestimate the potential toxicity of metals in the acid drainage (low pH) environment below
theHLP. Normally, toxicity is reduced as hardness is increased. However, an underlying
assumption of the criteria is that alkalinity increases as hardness increases. This assumption
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holds for many natural waters, however, at the Summitville Minesite hardness is relatively high
and alkalinity is low. Ranges of data collected by the USGS in 1993 at Station 45.4 from
Segment 3b of the Alamosa River are as follows:
Flow Season Analvte . Maximum Mean TVS
May-July Dissolved Copper 2600.0(Vg/L 1084.22Mg/L 30 Atg/L
October-March Dissolved Copper 780.00Mg/L 780.00Mg/L SO^g/L
May-July Dissolved Zinc 450.00^8/1 301MngfL 230^g/L
October-March Dissolved Zinc 437.00Mg/L 437.00j
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considered a viable exposed population currently or in the future. Off-site residents and potential
off-site recreational receptors will require evaluation during a baseline risk assessment
1.6.3.2 Exposure Pathways • ..........
An exposure pathway describes the route a chemical may take from the source to the exposed
individual. A complete pathway consists of four elements: a source and mechanism of chemical
release to the environment, an environmental transport medium, a point of potential human
contact with contaminated medium, and an exposure route. The transport medium can be air,
ground water, soil, surface water, etc. The route can be inhalation ingestion or dermal contact
with the medium. -- - .- .
Evaluation of the potential pathways suggests that most exposure pathways at the Site are
incomplete. Currently, the only pathway with sufficient data for assessment is surface water.
There is insufficient sampling data available to determine whether soil, ground water, and/or air
are exposure pathways.
To evaluate current and future risks, EPA is planning to complete a quantitative HHRA in 1995.
1.7 Description of Alternatives
This section describes the alternatives retained for detailed analysis for this interim remedial
action. A description of all options considered for operable unit can be found in the Focused
Feasibility Study Cropsv Waste Pile. Cleveland Cliffs Tailings Pond. Beaver Mud Dump, and
Mine Pits. Summitville Mine Superfund Site, Summitville, Colorado. The Cleveland Cliffs
Tailings Pond is now being referred to as the SDI. The alternatives were developed based on
Site conditions prior to the initiation of response actions by EPA at the CWP, BMD, SDI and
Mine Pits. Site conditions in 1993 warranted that a non-time critical removal action be
implemented to begin to address environmental hazards at the CWP, BMD, SDI and Mine Pits.
Currently, Site conditions dictate a transition from emergency response action to remedial action.
The purpose of this ROD is to provide the documentation required to complete the response
actions at the CWP, BMD, SDI and Mine Pits using CERCLA Remedial Authorities.
The Remedial Action alternatives were developed to eliminate or reduce the AMD generated
from the CWP, BMD, SDI and the Mine Pits. The following five alternatives were retained for
detailed analysis:
Alternative #1 No Action;
Alternative #2 Water Treatment; '
Alternative #3 Removal to the Mine Pits;
Alternative #4 Cropsy Valley Adit Drain; and
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Alternative #5 Cropsy Channel Drainage.
1.7.1 Alternative #1 No Action
Inclusion of a no action alternative is consistent with the NCP and is required under CERCLA
and SARA. The purpose of the no action alternative is to provide a baseline against which other
alternatives can be compared The no action alternative is the cessation of current water
treatment activity and sediment control on the Site. Existing treatment infrastructure would be
mothballed (mothballing is done to ensure reactivation without excessive expense for
replacement of equipment damaged by severe weather or other consequences of inactivity).
Ditches and ponds used to control surface runoff and sediment would not be maintained. Access
to the Site would not be restricted. Monitoring to record and evaluate contaminant transport
effects on human health and the environment would continue.
1.7.2 Alternative #2 Water Treatment
Alternative #2 will prevent AMD from migrating from the CWP, BMD, SDI and Mine Pits to the
Alamosa River system by capturing AMD generated from these areas and treating the water
using the existing water treatment facilities. Other water treatment systems were considered.
However, it was determined that the water treatment capacity in the existing facilities was
sufficient The existing facilities are capable of meeting discharge standards and are the most
cost effective for this interim action. It is anticipated that the existing treatment plants will
require replacement within a ten-year timeframe. Therefore, treatment costs have been estimated
for the ten-year period. Modifications, improvements and replacement of the existing facilities
will be evaluated during the sitewide feasibility study.
Part of the water treatment alternative is already in place. Water is being pumped from wells at
the foot of the CWP and treated at the CWTP. Additionally, French Drain water (CWP
underflow) is being pumped into the HLP. Currently, AMD generated from the BMD and SDI is
released to the Wightman Fork, without treatment To treat these flows, a trench would be
installed at the base of the BMD to collect AMD. Water collected in this trench and the SDI
would be pumped to the existing water treatment facilities. The water would be treated at the
water treatment facilities to meet discharge standards prior to release to the Wightman Fork. It is
estimated that an average of 161.4 million gallons per year (MGY) of water would require
treatment
1.7.3 Alternative #3 Removal to Mine Pits
The intention of this alternative is to eliminate or reduce the generation of AMD by isolating the
waste from water and/or oxygen. The naturally occurring surface water seeps that were covered
during the construction of the CWP and the BMD would be uncovered. It is anticipated that the
water quality from these uncovered seeps and springs would be of sufficient quality that
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treatment would not be required. Thus, this water would be directed to Cropsy Creek or the
Wightman Fork without treatment. Also, acid generating waste and sediments would also be
removed from the SDL Wastes would be placed in the Mine Pits such that precipitation would
drain away rather than collecting in the Mine Pits. Thus, reducing the hydraulic loading to the
underground workings.
The CWP would be excavated to an elevation of 11,620 feet with loaders and trucks, transported
to the Mine Pits, and used to fill the Mine Pits. Based on historical data and aerial photographs,
this excavations should expose the majority of seeps covered by the CWP. If the excavation fails
to uncover any significant seeps and springs, additional CWP material will be excavated by a
series of cuts. The depth of each cut will be 10 ft in thickness to conserve both capital and
manpower expenditures. The flow from seeps and springs that are exposed and surface water
runoff will be diverted into Cropsy Creek. After excavation is completed, the area would be
vegetated.
The acid generating wastes materials found in the BMD and SDI will be excavated or dredged
and placed in to the Mine Pits. The flow from the seeps and springs that are uncovered from this
excavation will be diverted to the Wightman Fork. Once all of the waste material had been
removed the area would be vegetated,. .The SDI would be converted to a storm water
management pond.
The provision for the short term treatment of water expressed from the uncovered springs and
seeps is included. Due to mining wastes placed over the springs and seeps, ground water located
under the waste piles may have become contaminated. Water treatment would be necessary prior
to release the water from the springs and seeps until the contamination has been flushed from the
ground. It is anticipated the water quality in the uncovered springs and seeps will rapidly return
to premining conditions.
Prior to placement of mining waste into the Mine Pits, a clay liner will be placed in the bottom of
the Mine Pits to a finished thickness of three feet The clay liner will extend up the pit walls 60
feet in the South Pit and 40 feet in the North Pit A five foot layer of lime lain dust will be
placed on top of the clay liner in the bottom of the Mine Pits. The lime kiln dust is being placed
in the Mine Pits to neutralize any AMD generated prior to completing construction. The final
surface contour in the Pits would be self draining and capped to reduce the volume of water
percolating through me waste material placed in the Pit
The estimated quantity of mining waste to be moved to the mine pits is 4.5 million cubic yards.
An estimated volume of 160 million gallons per year of AMD would not be generated if this
alternative is implemented.
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1.7.4 Alternative #4 Cropsy Vallev Adit
The intention of Alternative #4 is to eliminate or reduce the generation of AMD by dewatering
the CWP with a drainage adit and isolation of the waste currently located in the BMD, SDI from
water and/or oxygen. To dewater the CWP, a drainage adit would be located and driven into the
bedrock below the HLP and CWP. The adit would extend approximately 1 mile in length under
both piles at an inclined grade of 8% or greater from the portal entrance. Side cuts and drain
holes will be placed based on coring ahead of and to the side of the main tunnel to
drainage of the Cropsy Valley. Water entering the adit from different zones would be
segregated It is anticipated that some flows would require treatment prior to discharge to the
Wightman Fork.
The acid generating wastes found in the BMD and SDI will be excavated or dredged and placed
in to the Mine Pits. The flow from the seeps and springs that are uncovered from this excavation
will be diverted to the Wightman Fork. Once all of the waste material had been removed, the
area would be vegetated and the SDI would be converted to a storm water management pond.
The provision for the short term treatment of uncovered springs and seeps is included. Due to
mining wastes placed over the springs and seeps, ground water located under the waste piles may
have become contaminated. Water treatment of these springs and seeps would be concluded one
of the contamination has been flushed from the ground. It is anticipated the water quality in the
uncovered springs and seeps will rapidly return to premining conditions.
Prior to placement of mining waste into the Mine Pits, a clay liner will be placed in the bottom of
the Mine Pits to a finished thickness of three feet The clay liner will extend up the pit walls 60
feet in the South Pit and 40 feet in the North Pit A five foot layer of lime kiln dust will be
placed on top of the clay liner in the bottom of the Mine Pits. The lime kiln dust is being placed
in the mine pits to neutralize any AMD generated prior to completing construction. The final
surface contour in the Pits would be self draining and capped to reduce the volume of water
percolating through the waste material placed in the Pit
The estimated quantity of mining waste to be moved to the mine pits is 2.5 million cubic yards.
An estimated volume of 160 million gallons of year of AMD would not be generated if mis
alternative is implemented. However, additional AMD may be released from the adit
1.7.5 Alternative #5 Cropsv Channel Drainage
The intention of Alternative #5 is to eliminate or reduce the generation of AMD by dewatering
the CWP with drainage channel in the Cropsy Valley and isolation of the waste currently located
in the BMD and SDI from water and/or oxygen. The drainage channel in the Cropsy Valley
would consists of re-channeling approximately 4,500 linear feet of Cropsy Creek starting at the
existing Cropsy Creek Diversion. The channel will traverse a path through Dikes 2 and 3;
through the northwestern portion of the HLP, including Dike 1; and continue on to the French
Drain Sump. The drainage channel is intended to provide a pathway for the water to be released
from the CWP.
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The entire channel would be excavated into bedrock to a minimum depth of 5 feet to
erosion. The channel would intercept flow from the french drain beneath the CWP. The channel
would be constructed to expose different qualities of waters. Uncontaminated drainage could be
released directly to Cropsy Creek; contaminated drainage would be diverted into the French
Drain Sump for subsequent treatment before release into Cropsy Creek.
The channel would be routed so that approximately 3,200 linear feet would be constructed in
andesite bedrock and 1,300 linear feet in quartz-lathe bedrock. The portion of the channel
located in quartz-latite bedrock would be lined with concrete, gunnite or grouted riprap, and
benned/ditched on both sides to prevent contact with acid-forming quartz-latite resulting in
contaminating the streamflow. Acidic waters collected in the underdrain and surface ditches
would be diverted for subsequent treatment A 10 foot wide road would be constructed on one
side of the channel to provide work stations and maintenance access.
The acid generating wastes found in the BMD and SDI will be excavated or dredged and placed
in to the Mine Pits. The flow from the seeps and springs that are uncovered from this excavation
will be diverted to the Wightman Fork. Once all of the waste material had been removed, the
area would be vegetated and the SDI would be converted to a storm water management pond.
The provision for the short term treatment of uncovered springs and seeps is included. Due to
mining wastes placed over the springs and seeps, ground water located under the waste piles may
have become contaminated. Water treatment of these springs and seeps would be concluded one
of the contamination has been flushed from the ground. It is anticipated the water quality in the
uncovered springs and seeps will rapidly return to premining conditions.
Prior to placement of mining waste into the Mine Pits, a clay liner will be placed in the bottom of
the Mine Pits to a finished thickness of three feet The clay liner will extend up the pit walls 60
feet in the South Pit and 40 feet in the North Pit A five foot layer of lime kiln dust will be
placed on top of the clay liner in the bottom of the Mine Pits. The lime kiln dust is being placed
in the mine pits to neutralize any AMD generated prior to completing construction. The final
surface contour in the Pits would be self draining and capped to reduce the volume of water
percolating through the waste material placed hi the Pit
This alternative would result La the excavation of approximately 1 million cubic yards of the
CWP, 12 million cubic yards of the HLP, 1.5 million cubic yards of the BMD/SDL. 4,000 cubic
yards of quartz-latite bedrock, and 8,000 cubic yards of andesite bedrock. The excavated
materials would be used to either recontour both the HLP and CWP or placed in the mine pits.
1.8 Comparative Analysis of Alternatives
Provisions of the NCP require that a limited number of alternatives that represent viable
alternatives be evaluated against nine criteria hi 40 CFR 300.430(e) (9). The alternatives are
evaluated against each of these criteria and then against each other to determine the preferred
alternative. Table 9 presents a summary of mis analysis. The alternatives were evaluated based
on Site conditions prior to the initiation of any response actions by EPA at the CWP, BMD, SDI
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and Mine Pits. However, Site conditions in 1993 warranted that a non-time critical removal
action be implemented to begin to address environmental hazards at the CWP, BMD, SDI and
Mine Pits. Currently, Site conditions dictate a transition from emergency response actions to
remedial action. The purpose of this IROD is to provide the documentation required to complete
the response actions at the CWP, BMD, SDI and Mine Pits using CERCLA Remedial
Authorities.
1.8.1 Criteria 1: Overall Protection of Human Health and the Environment
The overall protection of human health and the environment criteria addresses whether or not the
interim remedial action provides adequate protection and describes how risks posed through
exposure pathways are eliminated, reduced, or controlled.
Alternative #1, the no action alternative, does not alleviate the threat to human health and the
environment Toxic AMD would continue to be generated from the CWP, BMD, SDI and the
Mine Pits and released to the Alamosa River System under Alternative #1.
Alternative #2,3,4 and 5 are protective of human health and the environment Under Alterative
#2, the toricity of the AMD generated from the CWP, BMD, SDI and the Mine Pits is removed
by collecting the AMD and treating the water prior to release to the Alamosa River System.
Alternatives #3 prevents the generation of AMD by isolation of the waste from water and/or
oxygen. Alternative #4 is intended to prevent the generation of AMD by dewatering the CWP by
placement of a drainage adit in the Cropsy Valley and isolation of the waste currently located in
the BMD and SDI from water and/or oxygen. Alternative #5 is intended to eliminate or reduce
the generation of AMD by dewatering the CWP by installing a drainage channel in the CWP and
isolation of the waste currently located in the BMD and SDI from water and/or oxygen.
1.8.2 Criteria 2: Compliance with ARARs
Alternative #1, no action does not attain the chemical specific ambient water quality ARAR
identified for Segment 3b of the Alamosa River. Alone, Alternatives 2,3,4, or 5 will not attain
the chemical specific ambient water quality ARAR identified for Segment 3b of the Alamosa
River. In conjunction with the other interim remedial actions, EPA has determined that
Alternatives 2,3,4, and 5 will Attain the surface water quality ARARs at the point of
compliance. .
Alternative 1 and Alternative 2 fail to implement acceptable BMP for surface water control.
Alternatives 3,4 and 5 eliminate contact of storm water with mine waste materials following
closure.
Alternatives 3,4 and 5 involve the placement of wastes in the Mine Pit These alternatives will
attain the RCRA Subtitle C Closure requirements.
Alternatives 3,4, and 5 involve reclamation activities. These alternative will attain the MLRB
requirements. .
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Alternatives 3,4,5 involve potential for significant fugitive participate emissions during
implementation. The ARAR will be attained :
After an investigation is completed, Alternatives 2,3,4 and 5 will attain all location-specific
ARARs.
1.8.3 Criteria 3: Long-term Effectiveness and Permanence
Long-term effectiveness and permanence refers to the ability of a remedy to provide reliable
protection of human health and the environment over time.
All of the alternatives, except for alternative #1, will provide long term effectiveness and
permanence. The long-term effectiveness of Alternatives #2,4 and 5 was found to be moderate
since both of these alternatives are dependent on long-term operations and maintenance. If
required operations or maintenance is ceased, the effectiveness and permanence of these
alternatives would be jeopardized.
Alternative #3 was found have the highest overall long-term effectiveness. With Alternative #3,
the majority of the seeps and springs covered by the CWP and BMD will be exposed. Thus,
water expressed from these seeps and springs will no longer come in contact with mining waste
that has the potential to produce AMD. In addition, acid generating wastes in the SDI will also
be removed. In Alternative #3, the mining wastes would be placed in the Mine Pits such that
long-term permanence is achieved.
1.8.4 Criteria 4: Reduction of Toxicitv. Mobility, and Volume through Treatment
Reduction of toxicity, mobility, or volume through treatment refers to the preference for a
remedy that reduces health hazards, the movement of contaminants, or the quantity of
contaminants at the Site. None of the alternatives reduce the toxicity, mobility or volume of the
sources of contamination through treatment However, the potential of generating AMD will be
diminished by placing the material into the Pit.
1.8.5 Criteria 5: Short-term Effectiveness
Short-term effectiveness addresses the period of time needed to complete the remedy and any
adverse effects to human health and the environment that may be caused during the construction
and implementation of the remedy.
Alternatives #2,3,4, and 5 utilize water treatment and other engineering controls to reduce
releases from the Site to achieve short-term effectiveness. The no action alterative is not
effective in the short-term. Under the no action alternative, it is anticipated that the contaminant
loading .to the environment would increase immediately.
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1.8.6 Criteria 6: Implementability
Implementability refers to the technical and administrative ease or difficulty of initiating and
performing a remedy. This includes the availability of materials and services to carry out a
remedy. It also includes coordination of Federal, State, and Local government efforts to clean up
the Site.
Alternative #1, the no action alternative was determined to be easily implemented. All that is
required from this alternative is to moth ball the currently operating water treatment facilities.
Alternative #3 was also determined to be easily implemented. Standard construction practices
are utilized in this alternative.
Alternative #2,4, and 5 were found to have a moderate degree of implementability. The
operation of water treatment facilities in the freezing winter conditions makes Alternative #2
difficult to implement For Alternative #4, the methodology of effectively diverting and
disposing of the waters within the adit is untried and unproven. Therefore, the ease of
implementing this alternative and the availability of material and qualified, experienced
personnel is suspect In Alternative #5, the installation of the lining required to control seepage
from the bedrock into the channel could be difficult to achieve. Also, it is uncertain if the french
drain under the CWP could be successfully intercepted.
1.8.7 Criteria 7: Cost
Cost evaluates the estimated capital plus the treatment and assessment (T+A) costs of each
alternative in comparison to other equally protective alternatives. The costs for each alternative
are summarized on Table 9 and are presented in detail in the FFS.
Alternative #3 has the lowest present worth costs with the exception of the No Action alternative.
Alternative #5 has the next lowest present worth costs. Alternative #2 has the highest present
worth costs. :
1.8.8 Criteria 8: State Acceptance
The State of Colorado has worked in partnership with the EPA throughout the development of
this ROD and concurs with the selected remedy.
1.8.9 Criteria 9: Community Acceptance
The Proposed Plan was issued to the public in August 1994. Two public meetings were held in
Alamosa, Colorado to present the Proposed Plan and to take public comment The community
response to the alternatives is presented in .the Responsiveness Summary for CWP, BMD, SDI,
and Mine Pits, which addresses comments received during the public comment period.
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1.9 The Selected Alternative
Based on the comparative analysis of the nine criteria, Alternative #3, removal to the Mine Pits is
the selected remedy for the CWP, SDI, HMD, and Mine Pits interim remedial action.
The major components of the selected interim alternative include:
Excavation of the CWP to an elevation of 11,620 feet
Excavation of the BMD and SDL
Line the bottom of the Mine Pits with a layer of pH neutralising material.
Placement and capping of excavated material in the Mine Pits.
1.10 Statutory Determinations
The selected remedy meets the statutory requirements of Section 121 of CERCLA as amended
by SARA. These statutory requirements include protection of human health and the
environment, compliance with ARARs, cost effectiveness, utilization of permanent solutions and
alternative treatment technologies to the maYimiim extent practicable, and preference for
treatment as a principal element The manner hi which these requirements are met utilising the
selected remedy is presented in the following discussion.
1.10.1 Protection of Human Health and the Environment
The selected remedy provides interim protection to human health and the environment by
removal of wastes from the CWP, BMD and SDI and placement in the Mine Pits. The waste will
be capped to reduce the volume of water percolating through the waste material placed in the Pit
The remedy will reduce the volume of AMD originating from the Site which is severely
impacting Wightman Fork and the Alamosa River.
1.10.2 Compliance With Applicable or Relevant and Appropriate Requirements
Under Section 121(d)(l) of CERCLA, remedial actions must attain standards, requirements,
limitations, or criteria that are applicable or "relevant and appropriate" under the circumstances
of the release at the Site. The selected remedy meets all applicable or relevant and appropriate
requirements of State and Federal Laws or waives these requirements in accordance with Section
300.430 (f)(i)(ii)(C)(l). The interim remedy rapidly reduces risk and will not exacerbate Site
problems or interfere with the final remedy.
Specifically, this remedy will not attain the surface water quality Applicable or Relevant and
Appropriate Requirements (ARARs) for metals in the Alamosa River at this time. However, this
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action will comply with surface water ARARs when implemented in conceit with the other
interim remedial actions proposed for the Site.
1.10.3 Cost Effectiveness
The selected remedy is cost-effective because it has been determined to provide overall
effectiveness proportional to its costs, the net present worth value being $40,837,975. Removal
and capping is a proven technology in the protection of human health and the environment
1.10.4 TTti|irafton of Permanent Solutions and Alternative Treatment Technologies or Resource
Recovery Technoloies to the Maximum Extent Practicable
It has been determined that the selected remedy represents the maximum extent to which
permanent solutions and treatment technologies can be utilized hi a cost-effective manner to
address the control of AMD at the Summitville Site. Of those alternatives that are protective of
human health and the environment and comply with ARARs, it was determined that the selected
remedy provides the best balance of trade-offs in terms of long-term effectiveness, reduction in
mobility, or volume achieved through treatment, short-term effectiveness, implementability, and
cost, while also considering the statutory preference for treatment as a principal element and
considering state and community acceptance.
The selected remedy reduces the principal threats posed by the possibility of AMD entering the
surface water system by permanently reducing the generation of AMD from the CWP, BMD,
SDI and the Mine Pits. Water quality drainage from the Site is expected to improve as interim
remedial action is completed. This improvement, along with other actions being considered for
the Site, will result in decreased pollutant content in water feeding the Alamosa River and
Terrace Reservoir.
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2.0 RESPONSIVENESS SUMMARY FOR THE CROPSY WASTE PILE, BEAVER
MUD DUMP, SUMMITVILLE DAM IMPOUNDMENT, AND MINE PITS.
This Responsiveness Summary was developed in accordance with the EPA guidance document,
"Community Relations in Superfund: A Handbook" (EPA/540/R-92/009).
2.1 Responsiveness Summary Overview
Prior to the public comment period, the EPA and the Colorado Department of Public Health and
Environment (CDPHE) selected a preferred alternative for the CWP, BMD, SDI, and Mine Pits
remediation at the Summitville Mine Superfund Site (Site) based on information provided in the
CWPFFS. The preferred alternative specified in the IROD addressed the reduction of acid
generation caused by infiltration of surface waters into the sulfide mineral zones (including rock-
filled areas) on the Summitville Mine Superfund Site through containment practices. The
interim remedy addresses the principal threat posed by surface waters infiltrating areas that were
not addressed in other operable units, but were previously disturbed by mining and/or mining
related activities. The interim action is consistent with any future actions to complete the
remediation of the entire Site, and is a logical step in the remediation process.
The major components of the preferred alternative include:
Excavation of the CWP to an elevation of 11,620 feet
Excavation of the BMD and SDI.
• Line the bottom of the Mine Pits with a layer of pH neutralizing material.
• Placement and capping of excavated material in the Mine Pits.
Implementing this interim remedial action will achieve protection of human health and the
environment
The comments received during the extended public comment period suggest that the San Luis
Valley residents, the TAG Members, the Colorado Mining Association, and other Colorado
residents are concerned about several issues regarding CWP, BMD, SDI, and Mine Pit areas of
the Site.
The EPA held a public comment period from August 23,1994 to October 23,1994 for interested
parties to comment on the CWP, BMD, SDI, and Mine Pits FFS for the Summitville Minesite
and the Proposed Plan for the Summitville Mine.
EPA held public meetings on September 8 and October 12,1994 in Alamosa, Colorado to
present the results of the FFS and the preferred alternative as presented hi the document
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All comments received by the EPA prior to the end of the public comment period, including
those expressed verbally at the public meetings are summarised IP this Responsiveness
Summary^
22 Response to CWP, BMD, SDI, and Mine Pits Specific Comments
2.2.1 Summary and Response to Local Community Concerns^
2.2.1.1 Ground Water
Comment 1:
Will yon be conducting additional studies to gain a better working knowledge of the site's
hydrogeology? .
Response:
Yes, EPA will begin conducting additional hydrogeological studies in 1995.
Comment 2:
Will contamination of regional ground water be exacerbated after moving waste materials
to the Mine Pits?
Response:
The placement of waste materials in the Mine Pits is designed to reduce the generation of
AMD by encapsulating over two million cubic yards of potentially acid generating rock.
This reduces the impacts on regional ground water. Removal to the Mine Pits with pH
amendments will directly address the sources of contamination and will reduce the
toxicity, mobility, or volume of contaminated water at the Site by 80%.
2.2.1.2 CERCLA Process
Comment 3:
No cost/benefit evaluation of those alternatives was performed, which is typically included
in a feasibility study.
Response:
EPA is required to base decisions for Remedial Actions on nine evaluation criteria of
which cost is one of the criteria. A range of costs (i.e. low, medium, and high) was
discussed for each alternative.
Comment 4;
The removal of the CWP does not constitute an immediate threat to human health and the
environment and does not constitute an emergency situation that compels immediate
action.
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Response: ' '.
EPA had determined that an immediate threat to human health and the environment
existed* and conditions at the site justified the implementation of a nontime critical
removal action for removal of the CWP. This determination is documented in the EPA
Action Memorandum dated December 18,1992 (Ref: 8HWM-ER, Site DD#: Y3) which
states, "Conditions existing at the Summitville Mine present an immediate and substantial
threat to human health and the environment and meet the criteria for initiating a Classic
Emergency Removal Action (Removal Action) under 40 CFR 300.415 of the National
Contingency Plan (NCP)".
2.2.1.3 Storm Water
Comment 5;
Need Summitville Dam Impoundment area incorporated into Site storm water
management and other surface water plans.
Response:
EPA agrees. SDI area will be incorporated in the storm water management plan.
2.2.1.4 PreferredAlternative
Comment 6:
Does the S40.8 million price tag for the preferred alternative include monitoring costs?
Response:
Yes.
Comment 7;
Has waste isolation been tried and been found to be successful at other sites similar to
Summitville?
Response:
Yes. Almost every mine reclamation project has included in its plans the isolation of
waste materials. For example, New Jersey Zinc Company is consolidating mining wastes
in a repository at the Eagle Mine in Colorado.
.^
Comment 8:
If no immediate reduction of contaminated water flows was expected, what was the
rationale for the action taken in 1993 and 1994 regarding removal of the CWP.
Response:
EPA acknowledges that an immediate reduction in contaminated water flows may not
occur due to AMD that already may have flowed into soils and ground water below the
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waste piles. EPA anticipates that once the waste rock has been removed and
contaminated water has been flushed out, the water quality in the exposed springs and
seeps located under the existing CWP will return to pre-SCMCI conditions.
2.2.1.5 Summitville Dam Impoundment/Beaver Mud Dump
Comment 9:
The hydrogeologic setting of the SDI/BMD is significantly different than that of the CWP.
No assessment was performed by EPA to evaluate the amount and mechanism by which the
SDI/BMD contribute AMD to Wightman Fork.
Response:
The hydrogeologic setting of the SDI/BMD is similar to that of the CWP. In both areas,
springs and seeps located under the waste pile are responsible for the providing water
necessary for the generation of AMD. Section 2.1.2 of the FFS references the
hydrogeologic assessments performed for the SDI/BMD. In this section, it is estimated
that 36 J million gallons per year of AMD are generated from the SDI/BMD. This water
is presently not treated and discharging into the Wightman Fork.
Comment 10;
Does the chemical nature from the SDI/BMD warrant taking a response action?
Response:
The SDI is a historic sulfide rich tailings pond located within the former Wightman Fork
drainage bed. The Wightman Fork was routed around the SDL While the pond only
contains about 133,000 cubic yards of material, it is thought to be hydraulically
connected to the Wightman Fork and, therefore, providing AMD directly into the creek
(Ecology & Environment, Inc. 7/93).
2.2.1.6 Cropsy Waste Pile
Comment |1:
Another alternative that would effectively eliminate water buildup behind the dikes is the
redesign and construction of the CWP containment berm and French Drain System to
intersect the existing Heap Leach French Drain System. This alternative was not
considered.
Response:
EPA considered this option. However it was determined not to be feasible because it
would destroy the dike liner under the Heap Leach Pad.
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2.2.1.7Mine Pits
Comment 12;
What, if any, and how much material such as day was placed on the bottom on the mine
pits before wastes were disposed in them? If there's a clay layer, is this the same on-site
clay that was identified as being an acid-producing material? Will there be some kind of
material (for example concrete) used to line the walls of the mine pits so that water cannot
seep into the wastes?
Response:
During Phase I of the Cropsy Waste Pile Removal Action, a clay liner was placed to a
compacted three foot thickness on the floor and wall of the North and South Pits. Clay
used for this phase was capping material from the CWP. No testing for acid generating
contaminants was conducted since the primary purpose of the clay barrier was to prevent
upward migration of acidic solutions into the mine pits. In addition, the clay was to be
overlaid with lime kiln dust (LKD).
Comment 13;
Was the mine pit lined with a lime material to buffer acid production? If so, how much?
How long will this material's buffering capacity last?
Response:
To add buffering capacity and to offset any negative water quality impacts during
construction activities, LKD was transported to the site and placed in the Mine Pit
during Phase I of the Cropsy Waste Pile Removal Action. The LKD was placed in a
continuous 5-foot layer over the compacted clay liner in the lowest levels of the Mine
Pits. Approximately 1,800 tons of LKD was placed in the Mine Pits. The material's
buffering capacity is intended to last through the completion of construction activities at
the Mine Pits.
Lime kiln dust, comprised largely of calcium oxide, behaves as a base (i.e. would tend to
raise the pH of a given solution when introduced). Therefore, an acidic solution, when
contacting the LKD layer will be neutralized.
Comment 14; -
Relocation of CWP to the Mine Pits is implementable and would be as effective as the
design and/or construction of the liner and placement requirements. Currently only
compaction on the southern side of the Mine Pits is used and it is unclear how effective this
compaction will be.
Response:
Cropsy waste material was spread in horizontal lift thicknesses of 24 inches and 12-feet
wide along the perimeter of all of slopes of the Mine Pits and compacted with a tamping
roller. This compacted zone was designed to significantly reduce, or prevent, long-term
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infiltration of ground water from the perimeter of the Mine Pits into the potentially acid
producing waste materials. The majority of the CWP was placed in the South Pit in a
single 40-foot lift over the compacted clay liner and LKD.
Comment IS;
Design parameters for the cap on the Mine Pits are not discussed.
Response:
The design for the cap has not been completed. EPA will make the design available to
the public for review and comment after it is 90% complete.
Comment 17;
Design parameters for the cap on the Mine Pits are not discussed.
Response:
The design for the cap has not been completed. EPA will make the design available to
the public for review and comment when the 90% design document is developed.
Comment 18;
Clay liners from on-site materials have AMD potential. How is this potential minimized,
eliminated or controlled?
Response:
Clay liners installed to date have been in the mine pits and were used for preventing
upward migration of acidic solutions from the old underground mine workings. The clay
for these liners was taken from the CWP and have lower acid generating capability than
the Clay Ore Stockpile material.
Comment 19;
Caps contribute to poorer water quality since they rechannel contaminated water into
other drainage channels that weren't serviced by water treatment facilities.
Response:
Caps are designed to prevent surface water runoff from coming in contact with wastes
that are acid generating. Thus, surface water runoff from caps should be of sufficient
water quality so that treatment is not required prior to discharge from the Site.
2.2.1.8 Comparative Analysis
Comment 20;
Why were natural wetlands, such as the iron bogs located at the Site, not identified as an
alternative for the CWP, BMD, and SDI?
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Response:
Engineered wetlands and/or bogs are TBC as a final reclamation goal. Locations being
considered include the SDI/BMD sites. Research work is presently underway on the
application of wetlands to the Summitville Site.
Comment 21;
Why was capping the CWP in place not considered as an alternative in the FFS?
Response: •
The CWP was capped by SCMCI. The cap was effective in reducing the volume of
precipitation percolating through the waste. However, springs and seeps located under
the CWP provided a significant source of water for AMD generation. Thus, capping of
the CWP in place was found to be not feasible.
Comment 22:
Why was submergence of the SDI/BMD not considered as an alternative in the FFS?
Response:
Historically, containment and control structures have been constructed for the SDI/BMD.
These measures have been ineffective in controlling AMD from this material. The EPA
believes this is due to its placement within the Wightman Fork drainage and is being
located adjacent to the creek.
Comment 23;
The basis for the cost developed for each alternative was not provided.
Response:
Appendix E of the FFS provides details on how the costs were developed.
2.2.2 Comprehensive Response to Specific Legal and Technical Questions
This section summarizes and responds to the specific legal and technical concerns raised during
the public comment period. •
2.2.2.1 GroundWater
Comment 24;
How could water backing up behind the Reynolds Adit impact the integrity of the bottom
of the mine pits where the highly reactive wastes will be disposed? How will you know if
water has risen to that level?
Response:
There are many alternatives for controlling the water backing up behind the Reynolds
Adit Additional Ground water studies will provide the data needed to determine the
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best approach for controlling ground water. Monitoring wells placed in the mine pits will
be able to determine if the water has risen into the waste.
Comment 25;
This FFS does not include a description of the promised state-of-the-art ground water flow
model that was supposedly developed to make these necessary evaluations. The model, as
well as information on model assumptions, model hydrogeologic boundary conditions,
model parameters, and model calibration, should be included in the FFS. The results of
such modeling evaluations may significantly alter the conclusions of the FFS with regard to
replugging the Chandler Adit and placement of the CWP and SDI/BMD in the Mine Pits.
As an example, if the water table rises in the Mine Pits, they could be a new source of
AMD. Such simulations would have provided insight into the water table levels which
could affect conclusions regarding the effectiveness of the selected alternative.
Response:
When considering the back-filled mine pits as a future possible source of AMD, the
confinement and placement of the fill material must be evaluated as well as the material
itself. The CWP is made up of three distinct types of material: the mine waste material, a
layer of compacted clay subsoil material which functioned as a cap, and a layer of topsoil
about 10 inches thick covering the pile entirely.
Topsoil material, about 72,000 cubic yards, was salvaged from the surface of the CWP
and relocated. The clay cap material was stripped and placed in the bottom of the pits
and finished to a three foot thickness. This clay liner was placed continuously over the
floors of the pits and 40 to 60 feet up the pit walls. About 76,000 yards of clay were
employed in this manner covering 10.4 acres of pit area. To add buffering capacity and
offset negative water quality impacts, a five foot thickness of LKD was placed over the
. clay.
After the mine pits are back-filled to a finalelevation of about 11,765 feet, they will be
capped with natural materials, an enhanced materials cap, or with a geosynthetic
membrane. The resulting structure will amount to an encapsulation of the acid generating
material. Capping is a "containment technology" leaving the contaminant in place and
controlling migration.
At Summitville, the cap is intended to reduce the amount of water percolating down to
the waste material in the pit Water mat percolates through may become acidic but would
be neutralized upon contact with the LKD.
Comment 26;
The FFS does not provide an adequate description of the ground water flow conditions at
the Site. A discussion of the prevailing ground water flow systems should be provided,
including the ground water flow direction, permeabilities, and storage coefficients. Also,
there is no discussion provided on the regional and local hydrogeologic boundary
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conditions at the Site. It is unclear where the recharge and discharge (seep) areas occur,
and the hydrogeologic effect of the underground workings and their significance as a
hydrogeologic boundary condition are unknown. The text does not discuss how plugging of
the Reynolds Adit will affect the ground water table conditions at the site. If these
conditions are unknown, at least a qualitative description is necessary. "'
Response:
Ground water at the Site is present in a series of intermittent, shallow, perched aquifers,
and numerous springs and seeps exist Depth to water is variable with the exception th«tt
in the vicinity of the old mine workings, water depth can attain 300 feet
Plugging of the Reynolds Adit will reduce the metal loading to Wightman Fork and is
expected to cause resaturation of the South Mountain slope. It is estimated that
resaturation will take about seven years and that ground water, flowing northeast toward
Wightman Fork, will take about 20 years to reach Wightman Fork.
2.2.2.2 CERCLA Process
Comment 27:
The remedy for the CWP, BMD/CC, and Mine Pits was selected and implemented prior to
development of the ITS and without providing a meaningful opportunity for the public to
comment
Response:
See Comment 1 in Section 2.3 Summary and Response to General Comments.
2.2.2.3 Remedial Investigation
Comment 28:
Need Remedial Investigation site characterization plan.
Response: A sitewide remedial investigation and Feasability Study will be completed
in 1995/1996.
2.2.2.4 Summitville Dam Impoundment/Beaver Mud Dump
Comment 29:
The administrative record for this portion of the Site does not presently support EPA's
determination that the SDI area requires remediation.
Response:
As previously stated, it is believed that the SDI is hydraulically connected to Wightman
Fork and, Therefore, is a direct outlet for untreated AMD. It is also estimated that
SDI/BMD contribute 17,000 pounds of copper per year to Wightman Fork.
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2.2.2.5 Cropsy Waste Pile
Comment 30;
The FFS states that removal of the CWP to the Mine Pits will reduce and/or eliminate the
build up Of ground water above the HT.P Dikes 2 and 3 at the toe of the existing CWP,
thereby reducing the probability of AMD forming upgradient of the BHLP and thus
reducing the possibility of the crushed ore becoming acid forming upon completion of the
TTTjP detoxification. However, it is unlikely to be effective if considerable springs are left
below the planned levels of the Phase n CWP removal. The planned excavation may not
uncover all the seeps.
Response:
EPA based its excavation limits on historic area! photography and the historical
descriptions of the valley prior to placement of mining wastes in the Cropsy Valley.
Based on this data, a significant contribution of the seepage from CWP will be
eliminated. EPA will evaluate if further excavation is required after completion of the
Phase n Removal Action,
2.2.2.6 Mine Pits
Comment 31;
Effectively, a landfill is being created in the Mine Pits. Are State permitting requirements
for mine wastes used in the design? Are State permitting requirements for water treatment
sludges implemented in the design? Will post-closure monitoring requirements from the
State be met?
Response:
The EPA is not required to obtain permits for the implementation of response actions at
Superfund Sites. However, EPA must meet the substantive requirements of permits for
all actions taken. The State of Colorado has reviewed and concurred on the design for the
placement of the mine waste and water treatment plant sludges into the Mine Pits. The
scope of post-closure monitoring is being developed as part of the sitewide ground water
monitoring program. -
Comment 32;
An explanation of how the design prevents future production of AMD from seeping
through the adit workings is necessary in evaluating this alternative. The engineering
guidelines that are being used to place the materials in the pits, and how implementation of
these guidelines prevent future generation of AMD are not explained or described.
Response:
The design prevents the production of AMD by reducing the volume of water and oxygen
that comes into contact with the waste. By consolidating the waste in the Mine Pits, the
water from precipitation and seeps under the CWP and BMD will no longer contact acid
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generating materials. Also, the cap on the Mine Pits will be designed so that the majority
. of the precipitation will flow off the mine pits or be transpired by the vegetation. This
will significantly reduce the water flow into the Pits and underground workings.
Comment 33:
Information on how the materials will be compacted in the pits is critical in evaluating the
effectiveness of the remedy. If the materials are not properly compacted, then settlement
will occur. Settlement will cause cracking in the cap, which in turn will cause water and
oxygen infiltration, causing AMD generation.
Response:
The material was placed in the Mine Pits in horizontal lifts of 5-foot thickness.
Compaction of waste material placed in the Mine Pits was achieved by equipment travel
during placement Equipment travel was routed so to compact the material evenly.
Waste placed along the perimeter of the Mine Pits were placed hi horizontal lifts of 2-foot
thickness and compacted by 6 passes of a tamping roller.
Comment 34;
An estimate of the water budget through the Mine Pits before and after capping should be
included in the FFS for proper evaluation of this alternative.
Response:
Ecology & Environment, Inc. of Denver, Colorado,, in their July 1993 EE/C A has
estimated that the net precipitation into the mine pits to be 72 million gallons per year. In
then* alternative that utilizes hack-filling the pits and capping, approximately 50 million
gallons (69%) of this would be runoff and not contact the waste rock.
Comment 35:
EPA does not explain if, based on a surface water management plan, the resulting
increased runoff originating from South Mountain will constitute a potentially significant
source of metals loading. As a result, it can only be assumed that the cost of such surface
water management plan is not accounted for in the costing of such an alternative.
Response:
Surface water runoff from South Mountain could potentially be a source of AMD if the
runoff comes into contact with materials that have the potential to generate AMD. The
proposed plan only addresses storm water management for theCWP, BMD, SDI, and the
Mine Pits. A comprehensive storm water management plan is being developed and may
be part of EPA's Final Remedial Action(s) for the Site.
Comment 36;
Need ground water control plan to prevent inundation of wastes in pit Figure 6 of the
Reynolds Adit Control Program (10/94) shows that the water level has risen above bottom
elevation of the pits. In the event of requiring water level control by discharge from the
Reynolds Adit, the water removed should be treated.
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Response:
A ground water study will be started in 1995. The results of this study will be used to
support the final remedial strategy at the Site. Alternatives that may be considered
include flooding the waste in the pits and controlling the water level in the mountain by
releasing water from the Reynolds Adit valve. Flooding acid generating mining waste is
common practice. Flooding waste controls the generation of AMD by reducing the
availability of oxygen, a required element for the generation of AMD. If the water level
in the mountain is to be controlled by discharge from the Reynolds Adit valve, the water
will be treated if necessary to meet discharge limits.
Comment 36:
EPA has not assessed the homogeneity of the CWP and the SDI/BMD material to ensure
that mixing of the materials from the CWP and the SDI/BMD will not trigger chemical
reactions that will generate AMD.
Response:
AMD refers to a process by which the pH is significantly reduced in water as it comes in
contact with sulfide minerals and oxygen. The mixing of wastes will not trigger a
chemical reaction that will generate AMD. The elements needed to generated AMD are
present in both areas. This is demonstrated by the large volumes of AMD generated from
these areas.
2.2.2.7Reclamation
Comment 37:
Is there enough on-site material that can be used and is it suitable? The same stockpiles of
materials are mentioned in the Reclamation Focused Feasibility Study. Is there enough for
multiple remedial actions?
Response:
There is a f»yr»fft*^ amount of on-site p?atffrfcte for capping and final overall site
reclamation. Topsoils intended for use as a growth medium will have to be amended
with soil conditioners, modifiers, fertilizers, etc. EPA expects that, with proper planning
and use of amendments, sufficient material is available for all site remedial activities.
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Comment 38;
The FFS indicates that amendments will be added to the footprint of the CWP prior to
revegetation. However, the FFS does not provide a discussion of the quantity or the type of
amendments that will be used.
Response:
The amount and type of amendments that will be used to promote growth of vegetation
and prevent AMD will be determined during the remedial design. EPA will make the.
design available to the public for review and comment when the 90% design document is
developed.
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23 Summary and Response to General Comments
Introduction On August 16,1994, the United States Environmental Protection Agency (EPA),
Region Vm (EPA), issued four Focused Feasibility Studies (FFS) relating to proposed remedial
action work at the Summitville Mining Site. These four FFSs relate to: (1) Cropsy Waste Pile,
Summitville Dam Impoundment, Beaver Mud Dump and Mine Pits; (2) Heap Leach Pad; (3)
Water Treatment; and, (4) Site Reclamation. EPA requested public comment on the four FFSs
and extended the deadline for comment to October 24,1994..
Comment 1;
A number of commenters complained that some of the alternatives evaluated by EPA in
these FFSs are already being implemented without EPA having followed the remedy
selection and public participation procedures of the NCP.
In particular, various commenters objected to the continued placement of the Cropsy
Waste Pile into the Mine Pits pursuant to an emergency-like schedule, despite public
comment on EPA's previously issued Engineering Evaluation/Cost Analysis (EE/CA). This
prior public comment stated such action was inappropriate because EPA did not consider
the feasibility of capping the Cropsy Waste Pile in its original location and EPA failed to
consider potential short and long term impacts on AMD. Commenters believe removal of
the Cropsy Waste Pile and its placement in the Mine Pits will exacerbate site conditions.
In spite of these public comments, EPA awarded a contract in July 1994 to complete the
excavation and relocation of the CWP, BMD and SDI into the Mine Pits according to the
EE/CA and Action Memorandum. Commenters now object to EPA selecting the placement
of the CWP, BMD and SDI into the Mine Pits as a remedial action alternative.
Commenters have suggested that by selecting the EE/CA response action as the interim
remedial action, EPA has "pre-selected" the remedial action for the Cropsy Waste Pile and
has circumvented the public participation procedures mandated by the Comprehensive
Environmental Response, Compensation and Liability Act of 1980, as amended (CERCLA)
and the National Contingency Plan (NCP).
Commenters note mat both CERCLA and the NCP establish specific steps and procedures
that EPA must follow in selection a remedy for all or a portion of a CERCLA Site. See.
generally. 42 U.S.C. 9604,9621; 40 CFJL 300.430 and claim that EPA has not followed
the NCP procedures. The conunenter states that EPA justifies the implementation of the
allegedly "pre-selected" remedy by arguing that the public participation undertaken
during the EE/CA process last summer satisfies the public's right to participate in the
remedial selection process for the Target Areas.
•
Response;
Excavation and consolidation activities associated with CWP, BMD, SDI, and Mine Pit
were initiated under an EPA non-time critical removal action pursuant to Section 300.415
of the NCP. Such removal activities are appropriate when, among other things,
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"excavation, consolidation, or removal of highly contaminated soils from drainage or
other areas ... will reduce the spread of, or direct contact with, the contamination." See
Section 300.415(d)(6) of the NCP at 55 Fed. Reg. 8843 (March 8,1990). Once EPA
determines such removal actions are appropriate, response actions shall begin as soon as
possible to abate, prevent, minimise or eliminate the threat posed by the contamination to
public health, welfare of the environment (See Section 300.415(b)(3) of the NCP at 55
Fed. Reg. 8843 (March 8,1990).)
According to the NCP, if a six-month planning period exists before EPA initiates a
removal action, EPA must conduct an Engineering Evaluation/Cost Analysis (EE/CA).
This analysis, although not as extensive as a Remedial Investigation/ Feasibility Study,
identifies the objectives of the removal action and analyzes the various alternatives that
may be used to meet these objectives, based on the alternative's cost, implementability
and effectiveness. The EE/CA is then released for public comment, according to the
public participation procedures established in Section 300.415(m)(4). Finally, after a
minimum 30-day public comment period, EPA issues an Action Memorandum which
documents EPA's selection of an appropriate non-time critical removal response action.
See_alsQ. "Guidance on Conducting Non-Time Critical Removal Actions Under
CERCLA," EPA/540-R-93-057, Publication 9360.0-32 (August 1993).
EPA meticulously followed the NCP-prescribed procedure in proposing and selecting the
EE/CA-based non-time critical removal for the CWP, BMD, SDI, and Mine Pit
(collectively, the Target Area). EPA published its EE/CA in July of 1993, solicitedand
accepted public comments on the EE/CA until early September of 1993, responded to
those comments in its' "Responsiveness Summary to the Engineering Evaluation/Cost
Analysis for the Cropsy Waste Pile, Beaver Mud Dump, the Cleveland Cliffs Tailings
Pond (now called the Summitville Dam Impoundment), and Mine Pits, Summitville
minesite, Rio Grande County, Colorado," and issued its Action Memorandum on
September 24,1993. EPA let a contract to begin implementation of this part of the
EE/CA-based removal action hi July 1994.
EPA is not arguing that providing .the public the opportunity to comment on the EE/CA is
sufficient to substitute for soliciting public comment on the Target Area FFS and
Proposed Plan. EPA agrees that the NCP does not allow EPA to satisfy its public
participation obligations for a proposed plan by reference to another document EPA also
agrees that the analysis EPA conducts to evaluate removal alternatives differs greatly
from the analysis conducted to evaluate remedial alternatives. For non-time critical
removals, EPA evaluates the alternatives in terms of effectiveness, implementability and
cost alone. The evaluation of remedial alternative is conducted using the nine criteria of
Section 300.430 of the NCP. The two sets of evaluation criteria are not synonymous.
EPA, however, did fully comply with the NCP-prescribed procedures for screening,
proposing and selecting remedial alternatives for the Target Areas in its Focused
Feasibility Study, Proposed Plan, and Interim Record of Decision (ROD). The removal
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alternative previously selected in the Action Memorandum was one of the alternatives
evaluated during EPA's remedy selection process. EPA took public comment on the
relative merits of all alternatives evaluated in the FFS vis-a-vis the nine NCP criteria and
proposed its preferred alternative in a Proposed Plan, issued in accordance with Section
117ofCERCLA. The alternative previously selected in the Action Memorandum, as
expanded in the FFS and Proposed Plan, met the threshold remedy selection criteria of
the NCP and provided the best balance of the NCP's "balancing" and "modifying"
criteria. It was selected as the appropriate remedial action in the Interim ROD for the
CWP. In accordance of the remedy selection criteria of Section 300.430(e) and (f) of the
NCP. .
EPA therefore selected both the EE/CA-based removal action and interim remedial action
according to the different, applicable standards and procedures of the NCP. the tact that
the two response actions are similar does not make the implementation of the previously
selected removal action illegal or invalid. Moreover, with the letting of the July 1994
contract, EPA was merely initiating the implementation of its validly selected removal
action. EPA's publication of the Target Areas FFS and Proposed Plan has no bearing on
and should not interfere with EPA going forward with this removal action,
Comment 2:
One commenter strongly recommends that EPA delay removal of the Cropsy Waste Pile
until all the potential ramifications have been properly evaluated by the public and by
competent technical consultants. Such an evaluation should be conducted after the "Use
Attainability Study/' which will characterize and evaluate downstream effects from the
Site, is completed. The commenter believes there is no reason to implement this remedy on
an expedited schedule.
Response:
The Use Attainability Study is being completed by the State of Colorado, Division of
Minerals and Geology. The findings of this study will be incorporated into EPA's final
response action for the Site. In the meantime, EPA believes the environmental benefits
that will be gained from the implementation of interim remedial actions at the Site far
outweigh me continued releases of mine waste for the Cropsy Pile.
Comment 3;
Commenters requested an explanation of EPA's rationale for issuing interim rather than
final RODs. These commenters feel EPA has no legal or technical basis for issuing IRODs
and that there will be additional costs associated with first implementing an interim
remedy prior to making a final remedy selection. They also expressed the belief that some
of the interim remedial actions may actually exacerbate site conditions and contamination
or may prove ultimately incompatible with final remedial action(s) for the Site.
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Response:
According to EPA guidance, interim remedial actions are appropriate to "take quick
action to protect human health and the environment from an imminent threat hi the short
term, while a final remedial solution is being developed." (See "Guide to Developing
Superfund No Action, Interim Action and Contingency Remedy RODs," US EPA,
OSWER Publication 9355.3-02FS-3 (April 1991), at p. 5.)
Deterioration of site conditions will lead to continued and heightened exposure of
sensitive human and ecological populations to heavy metals and chemicals (e.g. cyanide)
used by Galactic and others in their mining operations. The IRODs institute temporary
measures to stabilize the Site and prevent further migration of contaminants of concern
from the Site into surrounding soil, air and water media. Further, the types of interim
actions selected hi the IRODs, such as the relocation of contamination from one portion
of the Site (CWP) to another (Mine Pits) and the installation of caps to prevent further
migration of contaminants are exactly the types of response EPA guidance states are
appropriate to implement as interim remedial actions. See. "Interim Final Guidance on
Preparing Superfund Decision Documents," OSWER Directive 9355.3-02 (June 1989), at
Chapter 9.
Given the existing Site conditions, EPA is certain that filling the Mine Pits will
significantly reduce the flow into the Pits and prevent discharges of acid from the Mine
Pits into underground workings and ground water. Relocating other mine waste features
such as the CWP, BMD, and SDI to the Mine Pit will also mitigate these areas as sources
of AMD. Capping the Mine Pits will serve to eliminate or significantly reduce the
movement of contaminants of concern through water and air pathways. Treatment of
surface water and detoxifying the Heap Leach Pad will eliminate releases of metals and
cyanide: Overall, the implementation of interim response actions will quickly reduce the
imminent threats to human and environment receptors at and around the Summitville
minesite. EPA will also continue to monitor the progress of these remedies in
eliminating or reducing the release of hazardous substances from the Site and will
determine what, if any, final remedial actions are necessary to address the remaining risks
attheSite.
Comment 4:
Many commenters sought clarification which applicable or relevant and appropriate
requirements (ARARs) of federal and state statutes and regulations must be complied with
for remedial actions at the Site. Commenters wanted an identification of which ARARs
will be met with by the interim actions and which ARARs will be waived. One commenter
cautions against the use of "Technical Practicability Waivers" as shortcuts in the
remediation.
Response:
The ARARs clarification is provided in the specific Responsiveness Summary on
ARARs. Each IROD also identifies the relevant portions of federal and state
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requirements are being complied with or waived in the implementation of the interim
remedial actions. Commenter should be assured that all ARARs waived with the
selection of interim remedial action will be re-evaluated for the final remedial action(s)
fortheSite.
Comment 5:
One commenter noted that each of the FFSs states an "observational site approach" will be
taken as part of EPA's interim remedial actions. This commenter believes that an
observational approach may be an effective approach to site remediation, provided that all
the possible outcomes of the proposed action are identified, evaluated and monitored. The
commenter suggested that for potential outcomes that may have adverse consequences, the
impacts associated with those outcomes and the probability of their occurrence must be
qualitatively defined. If adverse consequences are likely, or that site conditions could be
make more complicated and problematic, then implementation of the proposed remedy
must be reconsidered. Finally, the commenter declared implementation of a remedial
action without an overall plan for each dealing with range of the potential outcomes is
inconsistent with a responsible observational approach at a complex site like the
Summitville Minesrte.
Response:
As discussed in the "Analysis of Alternatives" section in each of the IRODs, EPA has
considered all the relative merits and detriments of the potential remedial actions
evaluated. "Potential adverse consequences" of implementing the alternatives was
evaluated, as was EPA's ability to deal with these potential adverse impacts when EPA
reviewed the overall protection to human health and the environment, long-term
effectiveness and permanence, short-term effectiveness, implementability criteria of the
NCP. The interim response actions selected in the IRODs represent the alternatives that
provide the best balance of meeting these criteria. EPA will employ the "observational
approach" to continue to evaluate these interim remedial actions' effectiveness in meeting
these NCP criteria, EPA's RAO and performance standards and to determine what, if any,
additional final remedial actions are necessary to ensure that human health and the
environment are protected against unacceptable risks posed by hazardous substances
remaining at the Site.
Comment 6;
A number of commenters are concerned about EPA's estimate of costs to be expended at
the Summitville Site are too low. Commenters have calculated those costs (both removal
and remedial) as exceeding EPA's $120 million estimate. They are concerned that the
staggering amounts for interim response do not include the cost of the final remedy or
remedial investigation/feasibility studies presently being conducted at the Site.
Response:
The commenters are correct in their observation that EPA's initial cost estimate has been
exceeded with the collective costs of the interim remedial actions selected in the IRODs.
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The alternatives selected in the IRODs were screened for cost, and EPA believes that they
are cost-effective. As studies at the Site provide additional information and as remedial
actions are implemented, costs for remediation of the Site will continue to be reassessed.
Comment 7;
Commenters object to the backfilling of the Mine Pits and the plugging of the Reynolds
Adit, since in their view, these actions preclude a future beneficial use, that of re-mining.
The commenters believe that EPA's remediation activities should be immediately
terminated or suspended until the impact to future mining uses can be thoroughly
evaluated.
Response:
None of the proposed or completed EPA activities preclude further mining activities at
the Site. However, any future mining activities must be consistent with and not interfere
with the response actions EPA has implemented at the Site. EPA's remedial actions are
intended to prevent the exposure of humans and ecological populations to hazardous
substances. Any future mining activities that do not exposure these populations to
hazardous substances may be acceptable to EPA. It is anticipated, however, that EPA
will have to review any future mining plans to ensure the protection of human health and
the environment
Comment 8:
Commenters object to EPA's lack of a comprehensive Record of Decision for the Site and
the implementation of parallel or isolated and disjointed actions at the Site without any
overall plan or remedial strategy for the Site. To remedy this lack of coordination, the
commenters suggest that an independent board of technical experts review and select Site
response actions.
Response:
EPA believes that the interim remedial actions selected in the IRODs provide a
comprehensive, coordinated approach to addressing the risks at the Site. Specifically,
EPA believes that all the remedial measures to be implemented according to the IRODs
will go a long way in improving sitewide water quality by controlling surface runon and
runoff, erosion, leaching and metals and other contaminant loadings to the Alamosa
River.
Empowering an independent board of technical experts to review and select remedial
actions at the Site is improper under the Superfund law. Congress explicitly charged
EPA with the authority to select response actions to cleanup releases of hazardous
substances under the CERCLA Section 121 of CERCLA. In fact, this section of
CERCLA unequivocally states that "the President shall select appropriate remedial
actions determined to be necessary to be carried out under section 104 or secured under
section 106 which are in accordance with this section, and to the extent practicable, the • ~
national contingency plan..." [emphasis added]. The President has delegated that
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authority to select response actions at Superfund sites to the Administrator of EPA. The
procedures the Administrator must follow in selecting these cleanup actions are contained
in the National Contingency Plan.1 The NCP provides that affected and interested parties,
such as States, PRP and citizens are given the opportunity to participate in the selection
process, but it is clear that the Administrator retains the responsibility to select the
appropriate remedy. .
Thus, while EPA welcomes input from the community and neutral third parties
concerning the actual health risks from lead-contaminated mining wastes, EPA cannot
abrogate statutory responsibility to be the decision maker in selecting remedial actions for
Superfund sites. EPA can also not allow a third parry to determine the appropriate scope
of EPA's remediation plan, since it is our experience in identifying health and
environmental risks and designing the remedies to address them that Congress relied
upon when it empowered us with the authority to select and implement remedial actions
under Superfund.
Comment 9;
One commenter noted that downstream impacts are currently being ignored and avoided
despite the above stated RAO. Avoidance of downstream impacts adversely affects Terrace
Reservoir, household and municipal wells and allows agricultural land to further degrade.
Response:
Due to the Chandler Adit drainage, all downstream targets are being addressed as quickly
as possible. All three areas mentioned above are part of major research efforts included
in the justification of remedial actions at the Site. Terrace Reservoir is currently
undergoing a study conducted by the U.S. Geological Survey. Agricultural lands have
undergone several studies, including those conducted by Colorado State University. With
regard to household water use, local water supplies have been sampled twice and are
undergoing long-term water sampling.
Comment 10:
The same commenter stated a site drainage plan, which provides control for
surface/subsurface drainage, storm water and sedimentation management and nonpoint
source collection/treatment, is needed.
Response:
A site drainage plan has been implemented. A copy of the plan is available in the
Administrative Record.
1 See, e.g. Section 120(e)(4) of CERCLA (where if the head
of the relevant federal agency and the Administrator of EPA
cannot reach an agreement of the remedial action to-be selected,
the Administrator selects the remedy) .
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Comment 11;
One commenter identified a need for a waste management plan.
Response:
A number of the IRODs have elements is designed to meet waste management ARARs.
The Sampling and Analysis Plans describe how investigative derived wastes are
managed. Also, used oil is being recycled and, as stated in the Focused Feasibility Study,
sludge produced on-site is being recycled for metals recovery.
Comment 12:
One commenter is concerned that EPA does not have sufficient date to establish the
Summirville Dam Impoundment (SDI) as a source of sulfide-rich tailings and metals-laden
acidic water discharged to Wightman Fork. The lack of this data calls into question the
need to remediate the SDI at all, or at least the nature and extent of such remediation. The
commenter suggests EPA collect additional data regarding the nature and extent of
contamination at the BMD and SDI before proceeding with remediation of these areas.
Response:
Historically, the SDI and BMD area have been of significant concern to regulators from
the State. Water discharges emanating from these materials has been recorded as being of
poor quality. Based on existing data, historical precedent, and current sampling and
analysis information, EPA determined that the SDI and BMD are significant contributors
of man-made AMD at the Site. Data collected by Anaconda prior to SCMCI operations
states mat the mill tailings disposed of in this area are strong AMD generators.
Movement of these sources and the Cropsy Waste Pile to the Mine Pits allows capping of
four AMD sources in one action.
Comment 13;
One commenter argues that the FFSs and Proposed Plans fails to comply with the NCP
because: (1) these documents evaluate the "No Action" alternative for the Site as a whole,
rather than by the subject matter of each interim remedial action, (2) they fail to consider
naturally-occurring background concentrations of metals and acids in EPA's analysis of
alternatives, and (3) compliance with ARARs and/or ARAR waivers have not been
identified with any amount of specificity.
Response:
Alternative No. 1 for each of the Focused Feasibility Studies is a No-Action Alternative
related to that particular portion or media of the Site.
Naturally-occurring background levels of metals and acids were taken into account when
evaluating ARARs for the interim remedial actions. For example, EPA determined it was
appropriate to waive the Segment 3b stream classification as an applicable requirement
that must be met by the IRODs because of the historic contributions of metals and acids
from naturally-occurring sources. EPA will determine if this ARAR should be waived in
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any final ROD(s) for the Site when additional background and load reduction information
is collected.
Comment 14:
Cleveland-Cliffs Iron Co. and Union Pacific Resources Company submitted information
regarding their (or their predecessor-in-interest's) operations at the Site, their analysis of
the current state of CERCLA case law related to liability and legal arguments evaluating
their lability at the Site. These commenters also requested that EPA refer to the area
adjacent to the BMD, which EPA has referred to as the Cleveland-Cliffs Tailings Pond, as
the Summitville Dam Impoundment or some similar appellation.
Response: ...
While EPA appreciates information regarding parties' prior activities at the Site,
particularly if this information supplements EPA's CERCLA 104(e) information requests
or helps EPA to characterize the wastes at the Site, EPA believes a submission that
purports to provide comments on an FFS and Proposed Plan is an inappropriate forum to
state one's view of its liability at the Site. Such comments are more appropriately
submitted as part of a party's response to EPA's CERCLA Section 104(e) request, EPA's
Notice Letter or in confidential settlement correspondence between EPA and the
submitting party. A specific response to Cleveland-ClifiTUPRC's legal arguments will be
forwarded under separate cover.
Without any qualitative judgment on the merits of Cleveland-ClifiTUPRC's legal
arguments, EPA nonetheless agrees to hereafter refer to the area below the Beaver Mud
Dump as the..Siimmitville Dam Impoundment. Corresponding changes to this
' ' nomenclature will be T"^d? in all future EPA documents.
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RESPONSIVENESS SUMMARY: GENERAL WRITTEN COMMENTS RECEIVED FROM
CITIZENS AT LARGE OF THE SAN LUIS VALLEY
These written comments represent the universe of comments received through the end of the public
comment period.
Comment 15:
To whom it may concern: My name is Roger Gallegos I have lived in the San Lois Valley just
about all my life. Before the Summitville Mine came to exist, life was good. After they
exploited the government and us, life became much more difficult Take for instance, when
we would water our fields, we could catch fish hi our ditches. Another thing I have noticed is
the crop yield. Before the mine came in my meadow would yield 3000 to 3200 bales of hay.
When the mine had there spills I yielded 1642 bales. My best year while the water quality
improved was about 2853 bales. Now this may not sound important, but it is. I used to sell
hay for a living, and now I feed it to my cows. The mine has hurt my family in die pocketbook,
We have all been hurt by die mine in this community. The government should never have let
them start to begin with. Galactic Mining should be made responsible for the clean up. then
the Government for allowing them to do this. Since the mining company has gotten away with
this, we should not be made to suffer for other peoples mistakes. I say Summitville should be
cleaned up and restored, and our water be put back to normal My Great Grandfather made
a living with my ranch, as did my Grandfather and Dad. I want my kids and their kids to
continue making a living on what is theirs. They have that right, and not be forced to suffer
for what someone else was allowed to do. I myself believe the plan to filter the water down
below where the creeks meet, is the best idea. That system for 8 million, could save money and
work. Thank you for listening. The Gallegos Family. [Letter; undated; no other data given]
Comment 16;'
Dear Ms. Williams: As a farmland owner with land irrigated from die Alamosa River I am
deeply concerned and worried what the continued use of the contaminated water will
eventually do, not only to the land, drinking water from the wells, but also to the livestock and
products which are ultimately consumed by the general public. There are those who say it has
no ill effects on crops or livestock - but for how long. I do know it has played havoc with die
steel structures in the irrigation system. I'm under the Capulin Ditch and we have had to
spend over $40,000.00 replacing all steel structures. I may say that I was Water Commissioner
for this district and know the Alamosa River quite welL In this tune I never saw when so many
irrigation structures all deteriorated in such short time. As for those who say there never were
any fish in the Alamosa River - it is not true. Why else would the Game and Fish Department
consider it a fishing stream. People would ice fish all winter in the Terrace Reservoir up to die
time die mine started to dump die mess into the stream. I have lived here all my life and can
remember when we were little Dad would take us fishing there. As for the different options
to solve the problem it seems to me one that would treat all the water before it got into die
Alamosa River would be the one - probably in just one pond. Thank you Sincerely, Leo B.
Gonzales [Letter; dated Oct. 19,1994; address and phone number given] "
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Comment 17;
Dear Ms. Williams & EPA Summitville Team: Although I may be writing too late for the case
record, perhaps your comment period's been extended; in any case, the information leading
me to voice my concerns reached me after the original deadline. Your recommended plans
generally seem to stress reliance on systems that won't need too much up-keep once set in
place. The biotreatment aspect sounds favorable. However, it has come to my attention that
"caps" or "plugs" contributed to poorer water quality late hi this year's irrigation season,
since the caps rechanneled contaminated water into other drainage channels that weren't
serviced by your water treatment facilities. This indicates two planning factors to me: 1. you'll
want to assess where water will eventually seep out before you start filling the mine pits with
waste materials that are likely to displace ground water, and 2. it would make most sense to
locate your water treatment nnit(s) as far downgradient as possible, even if this entails
relocation of the existing facilities. I was also surprised that the reclamation plan 'mentions
no reseeding or tree transplanting details. Although it may or may not mean anything
scientifically, I notice that the Alamosa creekbed's rocks have a much less "rusty" surface
coloration near my house than they ever did during SMC's last four years. Thanks for your
efforts. Sincerely, Paul Sinder [Letter; dated 9/27/94; address given]
Comment 18;
To Laura Williams: I am writing to voice my concern on the clean-up efforts being taken at
the Summitville Minesite. .Mainly, I would like to state that I fully support the alternatives
researched and proposed to you by the T.A.G. committee. I hope the 1LP.A. system is flexible
and the T.A.G. proposals not only be reviewed, but also implemented. I thought the public
meeting on October 12th, was very informative and positive. It led me to believe that, although
yon have plans made and on paper, you are open to suggestions, criticism and change. The
T.A.G. proposal on water treatment is to my opinion a priority. It will make an immediate
difference in the water quality coming downstream and into our valley. I do hope this will be
realized as soon as possible, it seems common sense. Looking at the T.A.G. proposals, I think
they have found several solutions which promise more lasting and better results (and in some
cases a smaller price tag). A question I have too, is whether the E.C.C has the experience to
tackle the job up there. How many other experts and companies have been approached for
their expertise and advice? I am optimistic that you will find a way of working together with
the T.A.G. team hi finding the right solutions. I appreciate the work you are doing and am
keeping my fingers crossed that all goes welL I realize it's a tough and very complicated job.
Sincerely Lisa ter Knile A rural resident surrounded by Terrace irrigated land. [Letter;
undated; no other data given]
Comment 19;
Dear Ms. Williams: We want to support the recommendations made by the TAG for the
Summitville Minesite. We are concerned here in Conejos County about water quality and the
long term effects of the Summitville Minesite. We want the agricultural community in our
county to remain stable so our role as County Commissioners must look toward the future and
address the long term consequences connected with this site. Please take the TAG
recommendations seriously, the quality of our land and water will determine the future of our
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community. Sincerely, Le Roy Velasquez, Chairman Conejos County Commissioners
[Letter; dated October 18,1994; typed on Conejos County Government letterhead]
Comment 20: . . . : .
Dear Ms. Williams: We, as Board of Directors of the Valle del Sol Community Center in
Capulin, are extremely concerned about the Summitville Minesite and its continuation clean-
up efforts. We are very interested in the quality of our water for our homes as well as for our
farms. We support the enclosure made by the Technical Assistance Grant Committee. We
have showed our interest by making our community center available for meetings so that the
community will continue to be informed and to participate in the process. If there is anything
else we can be doing, please let us know. We are fuHy aware that the results of the Summitville
Minesite on the quality of our water will determine our livelihood in Capulin. Sincerely, Valle
del Sol Community Center Board of Directors. [Letter; dated October 18, 1994; five
signatures, spelling approximate: Rev. Randy Brennig, Delma Ramirez, James A. Quintana,
Cindy Medina, Julia Gomez-Nuanes; typed on Valle del Sol Community Center letterhead]
Comment 21:
Dear Ms. Williams, After reading the TAG newsletter and listening to Maya ter Kuile, I have
some misgivings about the E.P.A. plans for Summitville. The TAG suggestions surely seem
much more reasonable and straight forward than the EPA's approach. Their cost effectiveness
seems much more desirable also. As a new resident to the area I urge you to look again at
what has occurred to the Alamosa River; consider all of us who drink and irrigate in this area
and rethink your approach to what you (Le. EPA) are doing at Summitville. Thank yon
[Letter; dated 21 Oct 94; unreadable signature; address given]
Comment 22:
Dear Ms. Williams, I am writing you to voice my support for the Technical Assistance Grant
Committee's response to the EPA's action plan for clean-up of the Snmmitville Minesite. I
encourage your department to work with the TAG Committee for a thorough clean-up
operation with SLV citizen input Thank you for your consideration - Sincerely, Susan Sawyer
[Letter; undated; address given]
Comment 23;
Dear Ms. Laura Williams, I am writing concerning the Summitville mine clean-up. I attended
and appreciated the meeting on Oct 12, where the EPA presented their progress and future
for clean-up, and the TAG presented their answer and their suggestions on how to improve
the current trend. I have heard and read both sides of the issue. I, as do the residents of this
community, appreciate the work and the concern that the EPA has shown to clean up this
mess. Receiving Superfund status at such a fast rate was excellent We are really grateful to
the organization. My concern, as most of the community's, is the form in which the clean-up
is being performed. Some things were done in obvious haste due to the situation and the
consequences are now being observed Le.: the Reynolds adit plug and the Chandler adit leak.
The best thing to do, I believe, is to sit back and really assess the situation before any more
mistakes are made. The TAG has gone up there, researched the situation, consulted with
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experts and presented a different point of view. I listened to both sides (EPA versus TAG) and
came to the conclusion that the TAG had much better and faster results than the current
method. I was much more comfortable with the research done by the TAG group, seeing that
it was done more in depth and with well experienced experts. The cost, being of great concern
to many, would also be less if you reviewed the TAG group's point of view. There are many
that say that this river has always been polluted. Most of these people do not reside dose to
this river or even in the vicinity. Many live in other counties. I, as many other people in this
community did, fished, not only in this river but also on Terrace Reservoir, not too long ago
(1984-85). This river has not always been polluted. Maybe it's had if s ups and downs, but
it has never been dead. Not only do fish not exist any more but algae can't even grow any
longer. I am stating this because I have heard of people wanting the EPA to pull out, saying
that this river has always been polluted. These people do not know the facts and magnitude
of the damage that can occur and won't see into the future at what will happen to this valley
if nothing is done. I really hope that you really take careful consideration on all our letters,
and take the TAG group's suggestions seriously and implement their ideas. Thank yon for
your time and hope yon will have another update meeting soon. Sincerely, Nitschka ter Knile
and Steven Miller Home and Land Owners, 1/4 mile from Alamosa River. [Letter; dated Oct
20,1994; other data not given]
Comment 24:
Dear Ms. Williams: I have reviewed the TAG committee's recent newsletter and have
discussed the feasibility studies that were done and submitted to the E.PA. with a TAG
committee member. I would like to comment First, I would like to tell you that our farm has
been in our family for five generations. It is irrigated with water from the Alamosa river
which flows through our farm. My husband and I worked for over forty years to purchase
various parcels of land to make up what is now the present 435 acres. It would be a severe
financial loss to my family and to the other farm families here to be forced to abandon our
farms should .the water quality of the Alamosa become incompatible with safe crop and
livestock production. I feel the TAG committee has done an excellent job in their feasibility
study and in the suggestions they have made. I urge the EJ*.A. to consider water treatment
to become a top priority and to take the TAG committee's suggestion to build a water
treatment plant at the bottom of the Minesite, rather than to continue with the current
treatment plan, which is not only more costly, but would delay the treatment of the water in
time to prevent damage to thousands of acres of farmland. Sincerely yours, Leola T. Miller
[Letter; dated October 20,1994; address given]
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EPA RESPONSE TO WRITTEN COMMENTS RECEIVED FROM
CITIZENS AT LARGE OF THE SAN LUIS VALLEY
EPA will address citizen written comments in one response. All but one of the citizen comments
expressed direct concern with water quality issues as related to water quality conditions in the
Alamosa River resulting from mining activities at the Summitville Mine. Many citizen
comments received expressed support for the TAG committees' recommendations, particularly
regarding the location of the existing on-site Water Treatment Plant and associated costs.
EPA appreciates the feet that citizens have taken the time to attend the public meetings and
review the proposed plans and recommendations. EPA feels that citizen input is a component of
the decision making process and the concerns raised regarding water quality are valid and
deserve consideration. EPA further recognizes the time and effort expended by the TAG to
evaluate the proposed plans and develop constructive recommendations. As with citizen
involvement, EPA realizes that impartial technical assistance provides value in the decision
making process.
EPA is also cognizant of water quality issues which are central to human health, agricultural
impacts, and activities related to fishing, recreational or otherwise. EPA agrees with citizen
concerns especially as they relate to water quality.
It is the intent of EPA to integrate recommendations made by the TAG into the final
consideration of alternatives. These may be especially pertinent to specific elements of the Site
Reclamation options. In a letter from the Forest Supervisor of the San Juan/Rio Grande National
Forest dated October 17,1994, the USD A Forest Service expressed agreement-in-principle with
the preferred alternative #4 for site reclamation, stating that "it certainly seems to be the most
reasonable and cost effective in terms of restoring the area to a productive capacity*1.
The letter also stipulates that, pursuant to the current Master MOU (Memorandum of
Understanding) between EPA and the Forest Service, the Forest Service agreed to "provide
expertise related to natural resource management and protection...". In response to the proposed
plan for site reclamation, the Forest Service has offered expertise, "particularly in the area of
soil/surface reclamation", based upon its "considerable experience in conducting high elevation
reclamation". EPA feels that recommendations made by the Forest Service are valuable and will
be carefully considered in final selection of specific elements of the reclamation plan,
particularly those relevant to revegetation.
Regarding the alternatives for water treatment, EPA recognizes TAG concerns in discriminating
between Alternative 5 and Alternative 6 and TAG suggested modifications to Alternative 6.
EPA further recognizes similarities between the two alternatives. EPA acknowledges TAG
efforts in acquiring cost estimates from potential vendors. Relevant to costs for constructing a
new water treatment facility, EPA is cognisant of potential difficulties associated with acquiring
broad-based cost estimates from potential vendors who may or may not be as familiar with site-
specific conditions. Site specific conditions can dramatically affect proposed costs regardless of
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the experience and intentions of potential constructors. However, EPA will take TAG
recommendations under advisement and continue to seek comment from TAG members.
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2.4 Summary and Response to ARARs Comments
Comment 1:
A number of commenters noted that the ground water ARARs are also poorly defined,
causing EPA difficulty in determining whether gronndwater ARARs can be met by EPA
remedial activities. These commenters challenged EPA's adoption of surface water quality
standards for ground water resources, citing a lack of data. Commenters noted the fact
that surface water consists of snow melt and storm water runoff, plus baseflow
contributions from ground water sources. The commenter argued the Site has historically
exhibited high total dissolved solids (TDS) in the ground water and that EPA has not
adequately characterized other background water quality conditions. Water quality data
from surface water sources typically shows less TDS than from ground water tributary
sources. The commenter believes EPA has failed to account for this data in selecting
ground water quality standards. .
Response: ' ... '
EPA has determined that the classification system prescribed by the Colorado Ground
Water Standards is applicable or relevant and appropriate to assignment of Stamfords to
ground water at Superfund sites within Colorado. Since the Colorado Water Quality
Commission has yet to classify the Sitewide ground water, numeric ground water '.
standards are not currently applicable or relevant and appropriate to ground water quality
at the Site. The interim ground water narrative standard adopted by the Colorado Water
Quality Control Commission on July 29,1994, however, is applicable to the Site. This
standard, which became effective on August 30,1994, requires that the ambient water
quality as of January 31,1994, continues to be met This ARAR will be met by
compliance with EPA's interim action levels and with all surface water quality ARARs,
as discussed in each of the IRODs.
EPA, like the commenter, moreover, recognizes the hydrological interconection between
the surface and ground water flows at the Site, particularly during baseflow periods. EPA
expects, therefore, that once:the WQCC completes its use attainability study and
classifies Site ground water, mis classification will be applicable to the Site. This ARAR
will be attained by the final remedial action(s) for the Site.
Comment 2;
Two commenters objected to the use of RCRA Subtitle C performance standards and
design criteria for containment of existing waste rock, spent ore, and tailings at the Site.
Response:
While EPA agrees that RCRA Subtitle C requirements are not applicable to "Bevill
exempt" wastes, i.e., those from the "extraction, beneficiation, and processing of ores and
minerals," EPA has determined that RCRA Subtitle C requirements may be relevant and
appropriate to actions at CERCLA mining sites if the mine waste materials are
sufficiently similar to RCRA hazardous waste, particularly if the subject wastes fail the
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Toxicity Characteristics Leachibility Procedure (TCLP) or exhibit other characteristics of
RCRA hazardous wastes (e.g., low pH). (See "Superfund Guide to RCRA Management
Requirements for Mineral Processing Wastes, 2nd Edition," OERR Directive 93473a-12
(August 1991).) Further, if the disposal activity involves the use of a waste management
unit sufficiently similar to a RCRA regulated unit, and the unit is to receive wastes
sufficiently similar to RCRA hazardous wastes, the RCRA Subtitle C requirements
pertaining to that type of waste management unit would be relevant and appropriate.
(See 55 Fed. Reg. 87630.)
The portions of the RCRA Subtitle C performance standards and design criteria that are
relevant and appropriate to EPA's interim remedial actions at the Summitville site are
identified in the CWP, HLP and Reclamation IRODs.
Comment 3:
Another commenter noted that it was difficult to provide meaningful comment on the
ARARs for the CWP, BMD, SDI and the Mine Pits (collectively, the Target Areas) became
of EPA's vague and incomplete analysis of these standards in the CWP FFS.
The commenter attributed this vagueness to EPA's lack of discussion of how and why it
identified, adopted, or rejected specific potential ARARs and EPA's failure to identify the
ARARs, or portions thereof, that must be met by each interim remedial action.
Response: ,
While EPA was trying to promote efficiency by using the generic ARARs addendum to
the HLP FFS as a means to identify the universe of ARARs for all Site remedial actions,
EPA recogni7.es that this approach may have led to confusion over which ARARs were
applicable or relevant and appropriate for each IROD. In response to this comment, EPA
further defined the ARARs from Federal and State laws or regulations which must be met
by any alternative implemented as the CWP interim remedial action. The ARARs for the
Target Areas can be found in Section 1.5.4 of the CWP IROD. Since the sitewide
ARARs have already been identified in the "ARARs Addendum to the HLP Focused
Feasibility Study Report," this further refinement of ARARs as they relate to the CWP
IROD represents only a minor change to the CWP FFS and Proposed Plan. Consistent
with its "Interim Final Guidance on Preparing Superfund Decision Documents", OSWER
Directive 9355.3-02 (June 1989), EPA has determined that this minor change will have
little or no impact on the overall scope, performance, or cost of each alternative as
originally presented in the CWP FFS or Proposed Plan.
Comment 4;
Commenters question EPA's use of die most stringent stream classification - that of
Segment 3b of the Alamosa River - as the controlling surface water and ground water
quality ARAR. They state EPA has adequately explained why it has selected this stream
classification as the "controlling" standard. Further, commenters argue that the numeric
criteria based on the most stringent stream classification does not account for the lower
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classifications of other stream segments or for high background levels of copper, zinc and
other hazardous substances in the Wightman Fork and Alamosa River which are the result
of naturally occurring oxidation and transport processes acting upon highly mineralized,
unmined and unprocessed rock in the area. EPA, they opine, cannot remediate water
quality below naturally-occurring background levels. Lastly, commenters argue that the
State erred in designating Segment 3b of the Alamosa River as Class 1 Cold Water Aquatic
Life, and that this standard can never be attained because of background levels of metals.
They suggest that EPA waive this flawed classification based on the technical
impracticability of achieving these water quality standards and the State's failure to
consistently apply them, as evidenced by the creation of NCLs in the permit and 1991
Settlement Agreement
Response:
First, the commenters should understand that despite a Class 2 designation in Terrace
Reservoir (Segment 8), Segment 8 carries hardness-based TVS as the ambient standards.
Because the hardness in the Alamosa River decreases with increasing distance from the
water treatment plant at the Summitville Site, the ambient water quality standards in
Terrace Reservoir (Class 2) are more stringent than those assigned to Segment 3b
(Class 1).
The commenters should also note that the WQCC originally proposed to upgrade Terrace
Reservoir to Cold Water Aquatic Life Class 1 but declined because of limited data. In
fact, review of Exhibit 12 to November 1,1993 hearing held by the WQCC in Alamosa,
reveals the intention to collect needed data and review suitability for upgrade to a Class 1
designation. As stated in the HLPFFS, at this time EPA believes that employing the
Segment 3b standards will contribute to attaining Class 1 uses in Terrace Reservoir and
should contribute to attaining the existing, more stringent, hardness-based TVS assigned
to Terrace Reservoir. .
As the commentor is aware, the re-evaluation of water quality standards in Colorado
streams, rivers and reservoirs is an ongoing process controlled by the WQCC. In its
discussion, EPA specifically recognized the inconsistencies and concluded mat the
Colorado Water Quality Standards (CWQs) for Segment 3b of the Alamosa River, as the
applicable ARARs, will serve as the numeric interim remedial action goals for the Site.
At this time EPA does not have a basis for usurping the WQCC authority to determine
appropriate classification and water quality standards for the Alamosa River and its
tributaries. As additional data is gathered and the effects of the interim actions are
quantified, it is within the WQCC's authority to address all of the issues identified in
these comments. Until that time, EPA will use the existing standards as numerical goals
for the remediation.
In the HLPFFS, EPA made its intention to attain surface and ground water quality
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ARARs at Segment 3b of the Alamosa River clear. The attainment of the ARAR for
Segment 3b will be monitored using a "bubble" approach at the downgradient boundary
of the Site, monitoring point 5.5 in the Wightman Fork (WF 5.5). In this way, no single
interim remedial action alone is expected to bear the burden of ARARs attainment
Where the action-specific ARARs associated with interim remedial actions at the
Summitville Site require identification of an ambient-water-quality-based-end point (i.e.,
NPDES point source permitting), the applicable CWQSs for Segment 3b are established
using a model to back calculate compliance at WF 5.5. This modeling resulted in EPA's
establishment of interim action levels (XALs).
As noted in the HLPFFS, given the active interchange typical of alluvial ground water
and surface water in high mountain valleys, EPA has determined that attaining
compliance with surface water quality ARARs and the ground water interim narrative
standard will protect both surface and ground waters. This interchange will only compel
ground water cleanup to the extent required, in combination with other actions, to Attain
ARARs at the point of compliance (WF 5.5) and thereby meet the standards established
for Segment 3b.
The commenter should also be aware that the background concentrations of metals and
acids have been considered. At the triennial review of the Rio Grande Basin the WQCC
did recognize that background metals concentrations in Segment 3a can be attributed to
natural acid mine drainage from Iron, Alum and Bitter Creeks. Consistent with those
findings, the WQCC promulgated standards in Segment 3b which reflect the elevated
background concentrations and the wider pH range documented in Segment 3a. EPA
believes it has made its reliance on the WQCC's work very apparent in the table on page
3-6 of HLPFFS (see the values for chronic copper and chronic iron).
EPA did not participate in the development of the NCLs. .These negotiated numbers are
not duly promulgated and they are not the result of applying she specific data to duly
promulgated NPDES requirements (i.e. mass balance, low flow, etc.) to establish a
discharge limit The NCLs may indicate the appropriateness of a waiver at some time in
the future, but at the present EPA will reserve judgement on the use of and scope of
waivers.
The EPA believes that, as an objective, the protection of the Alamosa River as habitat for
a diverse range of cold water aquatic life is appropriate until the combined effects of the
interim actions come into effect Although it is impossible to precisely quantify, EPA
believes that when the combined, beneficial effects of the IRODs are realized, ARARs
will be attained in Segment 3b of the Alamosa River.
At that time, EPA will be able to better quantify the results and determine if additional
action or waiver is required. Likewise, the WQCC will have another opportunity in three
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years to evaluate the results of the interim RODs and use its own use attainability
authorities and ground water site-specific classifications to adjust standards accordingly.
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2.5 Summary and Response to Reynolds and Chandler Adit Questions
Although the Reynolds and Chandler Adit system is not a part of the current focused feasibility
studies, EPA recognizes the actual and potential contribution that this system may provide to
overall AMD contamination at the Site. Of the four FFSs, the Adit system is of most importance
to the Cropsy action since it is known that precipitation - approximately 72 million gallons per
year - and ground water were funneled by the Mine Pits into the historic underground workings.
The Adits previously drained this water (now ground water) from the mine workings which are
interspersed throughout the sulfide ore body. Contact with the sulfide ore resulted in the
transformation of the natural precipitation/ground water into AMD. This AMD then exited the
Reynolds Adit and flowed into the Wightman Fork stream.
As part of ongoing emergency activities, it was determined that the continual generation of AMD
from the Reynolds Adit could be substantially reduced by plugging the Adit system (see
Attachment F to Summitville Action Memorandum #2 dated January 28,1993.) This would
result in the re-establishment of the historic ground water table, thereby eliminating oxygen from
the mine workings/Adits. Concurrent evaluation of alternatives to address the Cropsy Waste Pile
included moving the CWP to the Mine Pits from which it was originally excavated. Overall
evaluation of the two actions (Reynolds and CWP) strongly favored the filling and capping of the
Mine Pits to prevent water infiltration through the sulfide ore body.
If the evaluation of the two actions had been unfavorable, it is likely that the Mine Pits would
have needed to be regraded and a drainage notch constructed to reclaim the area. The movement
of the waste piles to the Mine Pits, therefore, has actually resulted in a cost savings overall since
the CWP remedy meets the needs of both portions of the Site. In addition, the reduction in
volume of AMD generated by CWP and the Adits system will result in the decrease of Water
Treatment required at the Site and therefore costs for this third action. Evaluation of the Adit
plugs and the re-establishment of the ground water table is ongoing and the information
developed will be incorporated into RI/FS documents to support a separate Reynolds Adit/South
Mountain ground water ROD.
The evaluation of the two actions was discussed in Attachment F of Action Memorandum #2 and
section 5.0 of the EE/CA for the Cropsy Waste Pile, et al. An interim project report on the
Reynolds and Chandler Adit plugs was released on October 12,1994. Each of these documents
is included as part of the Summitville Administrative Record and is available to the public.
Comment 1;
The discussion in all the FFSs regarding AMD concentrations/ volumes attributed to
various sources should have provided a detailed analysis of the chemical mass balances
associated with water quality in and adjacent to the property [Summitville Site].
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Response:
As Tables 1-4 of the FFSs plainly demonstrate, there is not a steady release of chemicals
over time with which to develop chemical mass balances. The bulk of the contaminants
are released during periods of high surface water flow such as spring snowmelt or large
storm events. As discussed in section 1.32.3 of the FFSs, such an attempt is further
complicated by the varying nature of the geologic features encountered at the Site. To
attempt to develop a chemical mass balance for each chemical and geologic feature for
the various time frames does not add any greater understanding of the risks presented by
the Site.
Comment 2:
There is concern associated with backfilling of the Mine Pits (with CWP, SDI, and BMD
waste materials) since the data suggest that die Mine Pits and the Reynolds Adit are
hydraulically interconnected. Because of this hydrogeological connection, a greater
understanding regarding the geochemical interrelationship should have been undertaken
prior to commencing backfilling activities.
The combined impacts of implementing these two actions is still unaddressed, despite the
fact that the combined efforts could well be the reason that another or other alternatives
would be preferred.
Response:
EPA agrees that the hydraulic interconnection between the Mine Pits and the Reynolds
Adit is an area which bears special attention. If the ground water table - as a result of the
Adit plugging - were to rise above the level of the Mine Pits, then the relocated waste
piles could be subjected to a varying saturated condition. Because of this concern, EPA
placed a continuous three-foot (finished thickness), highly-impermeable clay liner on the
bottom and all sides of the Mine Pits. Placement and subsequent compaction by normal
construction traffic of the waste piles appear to have resulted in impermeable waste
materials. As a result, it is EPA's assessment that saturation of the relocated waste piles
is unlikely to occur as a result of infiltration by the ground water table.
A final cap over the Mine Pits is intended to divert surface infiltration so that saturation
of the piles does not occur as a result of precipitation events. The cap also serves to
eliminate oxygen, which is required for AMD generation, from entering the waste piles.
As a precautionary measure, a continuous five-foot layer of lime kiln dust was placed
over the clay liner for both the North and South Mine Pits (approximately 1,800 tons of
lime kiln dust). The lime kiln dust is intended to neutralize any AMD generated as a
result of moisture present within the waste piles as they are excavated and placed, and
AMD generated by precipitation events occurring during construction. In addition, any
surface water infiltration which may occur through the interim caps over the winters of
1993 and 1994 will also be neutralized.
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Should the waste piles become saturated despite the design and construction safeguards
described above, any AMD generation within the Mine Pits would take place under
saturated conditions in a high pH environment (high pH as a result of dissolving the lime
kiln dust). As with the ore body, this saturation would result in the elimination of oxygen
from the waste piles. This lack of oxygen would prevent the generation of AMD. While
a more detailed geochemical discussion may be useful for actual design considerations, it
can generally be understood that the sulfide ore body below the Mine Pits presents the
highest AMD generating potential for the entire Site. If saturated conditions can
minimize the AMD reaction for the sulfide ore body, then the same conditions will also
AMD reaction within the waste materials containing less sulfide.
Comment 3:
This section [1.4.13 of the CWP FFS] indicated that the Reynolds and Chandler Adits have
been plugged, bat that the long term effects of plugging the Reynolds Adit and Chandler
Adit, and the consequent rise in the South Mountain water table have not been determined.
EPA indicated in its response to comments on the EE/CA that a state-of-the-art
groundwater flow model that accounts for flow in fractures is being developed in order to
perform such evaluations. However, the Reynolds Adit was plugged prior to completion of
such a groundwater flow model evaluation and any publication of results of such
evaluations.
Response:
The intent of the "long-term effects" statement was to convey that EPA does not
definitively know the actual long-term effects which the plugging will achieve since
plugging was only recently completed in March 1994. However, the referenced model
has been able to provide some approximation of the resultant ground water table. At this
time, a report on the findings of this model is in the final stages of review prior to its
release to the public.
The development of the model was never expected to be completed prior to commencing
plugging activities. Instead, it was anticipated mat me model would be used to study the
effects of changes in site conditions (i.e., removal/remedial actions) on the ground water
and Adit system. The model has only recently achieved a relative level of accuracy and is
now being evaluated based upon actual field conditions. Because the Adit plugging*
were conducted as a time-critical, removal action, no formal public review process was
required, though the alternatives analysis for the Reynolds Adit has been a part of the
public record since January 28, 1 993.
Comment 4;
Plugging of the Reynolds Adit should have been evaluated as a long-term solution at the
Site rather than an Interim Remedial Action. Plugging of the Reynolds Adit could cause
the following: (1) increase of the water table into the Mine Pits, (2) groundwater to exit the
mountain via another shaft or adit (as was the case with the Chandler Adit), and/or (3) the
creation of additional point sources of Acid Rock Drainage (ARD) through seeps.
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Response:
As discussed previously, the Reynolds and Chandler Adits were plugged as a time-
critical, emergency removal action. However, this does not imply that the plugging of the
Adits is considered to be interim in nature. After initial consideration by EPA of the
three potential effects as listed by the commenter, EPA felt it best to evaluate the impacts
to the ground water table and the actual performance of the plugs as a whole system. As
more about the South Mountain ground water regime is known, then a final decision
regarding the regime can be developed for long-term considerations.
Comment 5; .
EPA apparently has not performed adequate groundwater investigations to evaluate the
short- and long-term effects of the Reynolds Adit plugging. Because of the complexity of
the groundwater flow system at the Site, as related to fracture flow and the hydrogeologic
significance of the mine workings and adits, a groundwater flow model is necessary to
evaluate rises in the groundwater table and the potential for significant groundwater
discharges through existing adits and shafts. Such modeling efforts must take into account
the effects of fractures on groundwater flow characteristics, groundwater recharge
primarily through the Mine Pits before and after filling and capping, groundwater
discharge seeps, and other significant hydrogeologic boundary conditions such as the
underground workings.
Response:
EPA agrees that the South Mountain ground water regime is complex in nature and can
have significant impacts upon the various actions discussed for the Site. As a result, EPA
has directed the development of a state-of-the-art, three-dimensional model with
assistance from the Office of Surface Mining. Each of the parameters identified by the
commenter and other considerations have been incorporated into development of the
model. The model has only recently achieved a relative level of accuracy and is now
being evaluated based upon actual field conditions. It is anticipated that the model can be
developed into a predictive tool for evaluating future actions to be taken at the site.
Comment 6:
As anticipated by individuals commenting on the EE/CA, plugging of the Reynolds Adit in
February 1994 apparently caused discharge of groundwater through the existing Chandler
Adit thus providing another source of ARD. As a result, EPA plugged the Chandler Adit
in March 1994. Shortly thereafter, the plug began leaking low pH metals-laden waters. An
explanation for the failure of the Chandler Adit plug is not discussed in the FFS. Failure of
the plug could be primarily a result of one or both of the following flaws in establishing the
plug design parameters: 1) failure to use conservative hydraulic parameters, such as using
the maximum possible hydrostatic head expected at the plug that would result from
plugging of the Reynolds Adit; and 2) failure to select suitable competent rock for keying
the plug. This section also mentions that corrective measures are planned for the Chandler
Adit, however, no specific discussion of the nature of the contemplated corrective measures
is provided.
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Response:
Concerns regarding potential discharge from the Chandler Adit once the Reynolds Adit
was plugged did result in EPA including plugging of the Chandler Adit as part of the
removal action. However, the work for both Adits was conducted in a concurrent fashion
and was not based upon actual discharge observed from the Chandler. The Chandler did
not fail until May 23,1994, which is a sufficient amount of time after construction for the
plug to have been fully effective.
EPA agrees that the subsequent failure of the Chandler plug is likely to be associated with
the plug design or the surrounding rock conditions. The corrective measures for the
Chandler are not discussed primarily because the plug failure was still being evaluated.
This assessment effort was initiated in November 1994 and it is anticipated that work to
repair or replace the Chandler Adit will be completed by Spring 1995.
Comment 7:
EPA should not repeat the same mistake of replugging the Chandler Adit without
performing the appropriate hydrogeologic investigations and evaluations. Replugging the
Chandler Adit may cause, as was the case in the Reynolds Adit plug, water exiting out of
another adit or shaft or significant hydrostatic pressures in the mountain that would cause
the development of multiple point sources via seeps at the base of the mountain. As
indicated above, the Chandler Adit is presently discharging low pH metals-rich waters
directiy into Wightman Fork. It is not known why EPA did not open the valve in the
Reynolds Adit to reduce or preclude flow from exiting the Chandler Adit and treat this in
the PITS facility prior to discharge to Wightman Fork. This demonstrates a failure on
EPA's part to develop an overall environmental strategy at the Site, as opposed to a
number of disconnected and uncoordinated individual actions.
From an emergency response standpoint, it may have been appropriate to keep the
Reynolds Adit open since water from the Reynolds Adit could be readily treated.
Response:
Based upon the short success during the time that the Chandler Adit was functional, it is
unlikely that replugging of the Adit will result in discharges from other adits/shafts. The
ground water model being developed tends to support this conclusion. However, it is
known that historic seeps did exist on South Mountain and it is reasonable to expect that
these seeps would redevelop. Even so, the rationale for plugging the Adit system was to
flood the mine workings and thereby eliminate oxygen from the reaction which generates
AMD. This will result in the gradual improvement of the South Mountain ground water
and, therefore, the water quality of the seeps.
The design for the Reynolds Adit included two separate plugs with piping between the
plugs. A valve which would allow EPA to drain the water behind the two plugs was to be
installed once the second plug was completed. After observing the better-than-expected
performance from the first plug, EPA determined that a second plug would be a
redundant expenditure and it was eliminated from construction. As a result, the
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capability to open the valve - as originally considered - did not exist at the time that the
Chandler began to discharge to the Wightman Fork. This valving capability has since
been installed and EPA has been treating the Chandler discharge at the PITS facility.
Rather than a lack of an overall environmental strategy for the Site, this incident is more
representative of the extreme physical and timing realities presented by the Site. Overall,
discharge from the Chandler Adit produced less flow and less copper concentrations than
experienced from the Reynolds Adit during the same time frame of the previous year.
Comment 8:
Plugging the Reynolds Adit may not, in the long term, reduce acid mine drainage flows and
may turn out to be a very expensive experiment Also, this interim action may actually
exacerbate site problems and, thus conflict with the National Contingency Plan.
Response:
Base upon current data gathering efforts and the recent predictive capability of the ground
water model, EPA has determined that plugging of the Reynolds Adit will result in a
reduction of contaminant transport from the Site. Therefore, these actions will not
exacerbate Site problems or interfere with the final overall site remedy. However, should
monitoring of the South Mountain ground water indicate that the plugging is actually
exacerbating Site conditions, the (now installed) valve within the Reynolds Adit can be
opened and treatment of the water initiated in the PITS.
Comment 9:
It is stated that "In 1993 and 1994, Emergency Response Removal Actions (ERRA) were
taken to reduce contaminant load in untreated Site water. This was achieved in part
by—prevention of AMD flow from underground workings—" Plugging the Reynolds Adit
probably did not reduce the contaminant load in untreated Site water
If no immediate reduction of contaminated water flows was expected, what was the
rationale for the precipitous action in 1993 and 1994 regarding plugging of the Reynolds
Adit? Alternative actions and consequences of combined actions could have been evaluated
on sound scientific bases thus providing for recommended alternatives with higher
expectations of achievements for interim remedies and final overall site remedies.
Response:
In the spring of 1993, discharge from the Reynolds Adit reached a peak flow of 763
gallons per minute with supersaturated concentrations of copper. Due to treatment
capacity limitations at the PITS facility, approximately 600 gallons per minute of the
discharge overflowed the holding pond and escaped untreated into the ground or
overflowed into the nearby creeks. While this occurred over a limited 3-4 week period,
plugging of the Adits eliminated this highly contaminated discharge to the Alamosa
drainage during the 1994 spring season.
In general, each of the remedies discussed hi the FFSs are anticipated to have a gradual
impact upon water quality and cannot be guaranteed to dramatically improve conditions
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over a short time frame. Also, because of on-going water treatment, implementation of
the remedies is expected to allow EPA to discontinue water treatment while maintaining
compliance with current water quality standards.
Comment 10;
This section [1.4.4.2 of the CWPFFS] does not provide an adequate description of the
groundwater flow conditions at the Site. A discussion of the prevailing groundwater flow
systems should be provided, including the groundwater flow direction, permeabilities, and
storage coefficients. Also, there is no discussion provided on the regional and local
hydrogeologic boundary conditions at the Site. It is unclear where the recharge and
discharge (seep) areas occur, and the hydrogeologic effect of the underground workings
and their significance as a hydrogeologic boundary conditions are unknown. The text does
not discuss how plugging of the Reynolds Adit will effect the groundwater table conditions
at the Site. If these conditions are unknown, at least a qualitative description is necessary.
The FFS does not include a description of the promised state-of-the-art groundwater flow
model that was supposedly developed to make these necessary evaluations. The model, as
well as information on model assumptions, model hydrogeologic boundary conditions,
should be included in an adequate FFS. The results of such modeling evaluations may
significantly alter the conclusions of the FFS with regard to replugging the Chandler Adit
Such simulation would have provided insight into the water table levels which could affect
conclusions regarding the effectiveness of the selected alternative.
In addition, EPA does not provide in the FFS a description of the proposed monitoring to
determine the effectiveness of the plugging in the short- and long-term. Evaluating the
effectiveness of the Reynolds Adit Plug will require monitoring of: (1) fluctuations in the
water table; (2) existing seeps; (3) changes in flow quantity; and (4) changes in water
quality through these seeps. Also, monitoring the development of additional seeps is
critical. Information regarding what EPA is currently considering as baseline for
monitoring and what methods wiU be used to evaluate the effectiveness of plugging is
necessary to determine the impact of plugging these two adits, particularly with regard to
final site remediation. Further, information on the monitoring efforts currently being
performed by EPA to monitor the potential development of additional seeps as a result of
the Reynolds Adit plug, and the results of such monitoring, are critical to evaluate the
effectiveness of the remedy.
Response:
EPA agrees that inclusion of the ground water model in an FFS is essential to evaluating
the effectiveness of a selected alternative for the South Mountain ground water regime.
EPA also agrees that the results of monitoring for the various considerations outlined by
the commenter are essential in assessing the impact of the Adit system plugging,
particularly with regard to final Site remediation. However, the plugging of the Reynolds
and Chandler Adits and their impact on the ground water are not the focus of any of the
four FFSs provided for public review and inclusion of the suggested information in these
FFSs is therefore inappropriate. Nonetheless, the modeling and monitoring efforts are
90
-------
actively being pursued and EPA anticipates that this information will be incorporated into
future RI/FS documents to support a separate Reynolds Adit/South Mountain ground
water ROD. These documents will be provided for public review and comment prior to
remedy selection. '
91
-------
3.0 REFERENCES
ALL REFERENCE MATERIAL IS AVAILABLE IN THE EPA ADMINISTRATIVE
RECORD.
92
-------
Table 1 Copper Content - Site Contaminated Water, 1993-1994 Record
1993/1994 ENVIRONMENTAL ANALYSIS-SUMMITVILLE SUPERFUND SITE
COPPER UBS)
(1983 11994
SAMPLE MAY JUN JULY AUQ SEPT OCT NOV DEC JAN FEB MAR APR MAY JUN
LOCATION
FRENCH DRAIN SUMP
STREAM A
VALLEY CENTER DRAIN
FDS-I
DIKE 1 SEEP
FOS-2
LPD-I 4 ROAD SEEPS
FDS-3
LPD-4 & 6 COMBINED
FRENCH DRAIN SUMP
TOTAL FLOW
HEAP LEACH PAD
STREAM B
CWP OVERFLOW (560-DO)
CROPSY WATER
(TREATMENT PLANTI
HLPllACHATt
(INFLUENT TO CDPI
UNDEROROUNO WORKINGS
STREAM C
REYNOLDS ADIT (AD 0)
PITS
(REYNOLDS ADIT TREATMENT)
CHANOLfn POSTAL
CROPSV CREEK
LPO-i
(EAST OF F. D. SUMP)
STREAM H
CROPSY CREEK
POND 4
STREAM F
POND 4 DISCHARGE
OTHER CONTRIBUTORS TO WIQHTMAN
STREAM 0
CLEVELAND CLIFFS
STREAM f
NORTH DUMP DRAINAGE
STREAM 0
CLAY ORE STOCKPILE (SEEP L|
TREATMENT DISCHARGE
TO WIOIITMAN FORK
MONTHLY TOTAL OP
CURRENT CONTRIBUTORS
MONTHLY TOTAL OP ALL
POTENTIAL CONTRIBUTORS
WF-S.S WIOHTMANFORK
653
1.138
12
827
• 3,181
8.348
38.364
83,242
12.770
'"'
281
3.624
0
FORK
4.438
3.388
2.305
23
64.248
117.687
47.436
1.121
1.418
364
314
3.840
4.037
""^
'37.866
110,739
16.661
~<>
188
860
761
3,804
3.465
1.028
48
105.231
166.660
71.181
831
282
&£.
61
1.823
781
*<:yiz..
33.162
34.432
18.760
'•?<*'
31
127
408
1.287
868
,')'&'
31
17.398
72.884
20.646
622
181
IB
34
1.613
333
•'•,'Ji'/."
24.688
2O.212
18,472
'•/,',"?
69
111
728
1.788
87
^%-t
29
4.48(
48.47C
6.424
1.688
186
35
46
899
348
'^%
22.708
18.272
18.272
'"'f
34
67
323
1,626
31
*i*&
26
1.874
46.173
3,683
683
120
38
37
629
148
£$
21,802
12.352
12,352
'<,'/
28
62
78
'/*?•'
873
4
"•" "is'}
39
1.036
3S.83E
93E
414
147
22
28
481
76
?$j
19.035
6,863
6,963
/-,; %
7
26
B
609
* f t '' /,
*&£
21
669
27.18C
789
417
122
16
28
482
26
- •£;
18.082
8.319
6,319
; '<&'
0
21
- -; ,
644
'/' , >'
'«?
13
87«
22.674
67(
483
104
'- - '„'
23
438
4
••t^y''
13.873
409
63
^ '\
17
374
- v t
'*&>>
ft£
'f-'';-
11
S3
16.786
47E
142
84
ffff ^
'- 'y
IS
'« ' '
'•'•I
"ft!
0
83
9.866
374
381
60
',v£
18
381
' /
2.843
8.047
112
140
>'," ' -
, „'„. ",
26
''„"
""'.Y
.':$
$%l
C
-3
12.417
39!
. 364
37
'£$,
139
492
*x
1.840
7.835
608
632
64
268
2.238
1.181
7,411
8.103
86
164
; ,-
'/;<. „'
169
'V •"
/" ' ' '/
/",/*•' '•
T", "• '
'<• 'sin •
0
83
10.411
80S
0
11.764
184
842
I.O02
468
1.613
876
6
16.181
33.088
20.424
2.160
1.601
302
78
2.410
1.484
8.833
8.018
1.128
0
83.788
268
671
1.868
991
6,110
1.810
237
24
84.830
114,33]
87.480
JULY TO JUNE
COPPER LOAD
UBS)
8.678
3.434
483
767
12.289
4.378
18.827
182.4BB
102.678
86.178
86.642
821
1.737
4.608
12.284
4.321
1.113
189
137.204
460.266
143.09:
PERCENT OF
CURRENT
LOAOINO
12.76%
68.83%
1.27%
3.29%
8.88%
3.16%
0.81%
0.14%
100.00%
'
PERCENT OF
POTENTIAL
LOADING
2.72%
0.97%
4.20%
42.76%
22.80%
21.22%
0.38%
1.00%
2.73%
0.86%
0.26%
0.04%
100%
-------
Table 2 Cyanide Content - Site Contaminated Water, 1993-1994 Record
1993/1994 ENVIRONMENTAL ANAIVSIS-SUMMITVIUE 6UPEHFUND SITE
CYANIDE
IIMJ Ii994
IAMHC • MAY JIM JULY AIM MPT OCT MOV DEC JAM H* MAN AM MAY JUN
IOCATMN
FMNCH OHAM 8UMT
SIRfAUA
VAUCV CENTER DRAM
«>»•»
DIM 1 SEEP
fOS-l
IPO-I * ROA08EIP9
tf>M
IPO 4 ft B COMBMf D
fKlNCH OHAIN SUMP
ItmUENTI
HEAP IIACH PAD
STRIAMB
cur OVERFLOW nso-oot
cflp/sv-tv/UM
(TREATMENT PLANT!
infltACHATt •
IMFIUENT TO COPI
UNOERaKOUNO WOIUMOI
tntMHC
REYNOLDS ADIT IAD-01
mi
(REYNOLDS AWT TREATMENT)
C/MWMMMMMI
CROPIV CREE*
lfO-»
(EAST Of f. 0. BUMF1
STRCAMH
CROPSV CREEK
POND 4
STRCAMf
PONO 4 DISCHARGE
K)Ht4 >4Wf
410
49
•
0
I.t4t
0
*
34,ltl
0
0
'K^ •• -1"
0
M
841
31
HI
0
I.JI*
o
,
n.oii
0
0
"ill' " 1
0
» ,\-
0
1.01 f
0
4 ^ ••
tl.ttl
0
0
"l
tt.914
0
0
. ? . ^! '
0
<»
248
7
(
0
M«
0
<**i--
tt.til
0
0
r'Al^ii4
0
*
392
7
28
0
41t
0
"",>''
o
?$,:*>#
B1
A>i£.
814
14
12
0
495
0
•• *'•• i
IS.J1S
0
0
i)j&f
0
«5
899
8
17
O
SI4
0
' '-.'•'-.
•. ' <
n.ess
0
0
,'„&&__
0
0
0
' Sx '*'
v>^'
1,-:?!,,
ijf
648
3
/: . *-;'-
0
«5
0
:,:->
13.3ft
0
0
..- rf,, -''
" '*."--
J-- .s".
O
> f "• f
fs
822
2
'( ?
"*\-**4
0
4M
, > -
' ••*' ' *•>
-V, x
A«f2
0
0
i 'it
?K'^,S
<-
.
<.?~, -i
1
' '
f- v
V'A n
•^ _,
: "• "*•
^i
™_gil.
89)
8
B
0
633
0
0
S.1M
0
0
0
'•''''V,^
•>' • if
I
399
14
12
0
486
0
0
B.I 26
0
0
0
0
7
p
'1 •*
O
0
JULY TO JUNI
CVANIOS iOAO
UBtl
1.418
•1
102
2
7.348
0
0
198.717
0
0
0
0
84
8
HIM
PERCENT Of
CURRENT
lOAtHNO
0.00*
0.00*
0.00*
I.86K
1.02*
PERCENT Of
POTENTIAL
LOADMO
4.42*
BB.84*
0.00*
0.00*
0.01*
0.00*
OTHER CONTIMUTOM TO WIOHTMAN fORK
sracAMO
CIEVEIAND CIVF8
sraiAut
NORTH DUMP DRAtMQE
STREAM 0
CLAY ORE STOCKPILE (SEEP U
W64 JUIHJ O/SCHAHGt
TO WMHTMAN f OMC
MONTHLY TOTAt Of
CURRENT CONTRIBUTOR!
MONTHIY TOTA1 Of All
POTENTIAL CONTRIBUTOR*
Wf-S.t WIOHniAH fOHX
1
0
• fl
IB]
tic
JS.4I1
1.61
0
0
0
164
Ml
30.41
1.32
0
0
> *, ;
i^'/l ,
100
201
it.ite
221
0
0
„;>:,?'
16
U
13.871
tl
. % ^ "" Sf*
: t
^l . ''.
*:?£
,! t-
,..^,=r
0
1
f.241
t
v ~ /
•% X--'.
.J«^»^
X»" f1-"
*>!""
0
I
•.101
c
%-L *
^${XK
^ '•• ">**
-'-:>/,
•= * ^ ..
0
1
7.7M
39
0
•* ' ^ •
0
38
41
f.«3!
28C
0
• a
0
III
124
. Mil
2.11
0
0
0
722
7B4
118.12)
4.131
0.00k
0.00*
0.03%
•2.09*
100.00*
-
0.00*
0.00*
0.00*
0.43%
100%
-------
Table 3a Site Surface Water and Treatment Plant Flow Rates, 1993-1994 Record
1993/1994 ENVIRONMENTAL ANALYSIS SUMMITVILLE SUPERFUND SITE
FLOW RATE IQPMI
(1893 11984
SAMPLE MAY JUN JULY AUO SEPT OCT NOV DEC JAN KB MAR APR MAY JUM
LOCATION
HIGH FLOW
IGPMI
17/83 TO 6/841
LOW FLOW
(UPM)
17/83 TO 6/841
FRENCH DRAW SUMP
S1RC AM A
VALLEY CENTER DRAIN
fOS-l
DIKE 1 SEEP
FDS-i
IPD-1 i ROAD SEEPS
FOS3
LPO-4 A 6 COMBINED
fKCNCH DRAIN SUMP
IEFFLUENII
SB
40
1
26
1S1
67
29
19
26
190
72
B
7W-
'tax,*'
14
124
69
6
3
12
103
ei
6
3
12
88
71
3
3
13
70
70
4
3
11
70
74
3
2
10
70
73
1
v/*~
-V ?
7
70
70
1
'k^'
6
70
70
1
4^x
6
70
78
1
/&-fj/»
ef fS S*ff f
6
87
HEAP LEACH PAD
STRfAMS
CWP OVERFLOW 1660 DO)
CROPSYWATIR
(TREATMENT PLANT!
IILPttACHATt
(INFLUENT TO COP)
UNDERGROUND WORKINGS
STttCAM C
REYNOLDS ADIT (AD 0)
«rs
(REYNOLDS ADIT TREATMENT)
CROPSV CREEK
IPO 2
(EAST Of F. D. SUMP)
STRfAMH
CROPSY CREEK
POND 4
STHCAMF
POND 4 OISCIIARQE
IOWA ADIT
3B4
' I
694
486
74
•••:.>.•/:-:: •••;;••::•••
26
2.606
191
/, xf/ '
723
7B3
113
2B
2.608
47
JsJ/r^S
877
396
192
•*•",•••.-•••;•:•&•#&.
1
843
IB
,;yv-
686
272
218
•::.*: £::•¥:••;:*.:
6
327
16
'%&?
847
229
237
2
239
B
"','<-(
< V^ f
774
ISO
160
2
104
4
"V *,sf
V(»?
874
119
119
ff "* /' ' ' '''
'''<4<''.:.
69
2
**"'v;
639
87
97
T^'-;
62
0
,tj#,1
860
48
69
' •;$?' ;
^.^ '
62
*. 'f
f// •'
621
8
87
:^-
.('v. «!>..'.
36
' '/ '*''^*',
''-.',''''' ,
108
848
7
72
~-^ "'-Y-k
:".'<,$'''
41
V-"5^'
74
881
8
86
, ,>-$•'
- > **V,
89
132
14
4
10
186
28
176
634
0
13
1,346
119
38
20
13
181
44
182
760
68
0
29
2.480
132
38
20
14
186
47
178
774
388
237
28
2.460
69
1
2
e
70
0
74
834
B
1
86
V
/^ : fJ
766
-ft* '-
1(6
<' i''-.
316
, , /
136
-. '' f, * *
33
<$.;,.
4
v' ^j".
'f f
' Vi
•* ' ,'
, < ,, i'
'/vL./
V ,''„
'' i' i—
•* ' /f
'v/
> ':
948
20
• 768
134
848
N/M
N/M
OTHER CONTRIBUTORS TO WIOHTMAN FORK
STRUM 0
CLEVELAND CLIFFS
STRCAMt
NORTH DUMP DRAINAGE
STttCAM O
CLAY ORE STOCKPILE (SEEP I)
/ ff ' % ""
MONTHLY TOTAL OF
CURRENT CONTRIBUTORS
MONTHLY TOTAL OF AIL
POTENTIAL CONTRIBUTORS
WF-I.S WIGHTMAH fORK
202
2B4
49
,-
3.762
4.935
I6.56£
IBS
282
66
? V i
"'' ' ,'
4.440
6.661
13.623
62
87
.,.,.,..,
*>'', '
' '-If, "/'
! $,&
1.083
2.123
3.363
83
13
:-:r ;
/ ^ ^ '
V' '-"' /,J
^•*^-> ' ' f
786
1.700
2.32C
69
4
t',,'/ ;•
' W» '
'.'?&,"
440
1,420
1.131
43
2
'5 :•>;
'" i" '
<,•' ,y?.-,\ '
Mn&
182
1.214
. 881
33
' /S-s ''
/•''!<
:- -,*
'/•• *' ' .
.,,">.*'<
tot
873
70E
37
ffSs
?' '••
'-•: s*
it*?';.
99
807
493
",„*'$"#' ',
, jf V%
•" * f "
','?,<>'*,
f% / \
A$t f ,'
'^&L
82
ete
34^
<:f^;
/ ^ "* ••
^ -
'-''-.",.'"
'&n£^
38
736
233
i^
X' ' y
^^ ^
; ,-.
•* ^ ••
"vr
^^/.- v* ^'
'* '//<
< ,* '%' ^^.
/5 % V, 5
41
874
286
""'':., '}-
''•• ''',,;,,
•<•;?'< '••
X ft '' f
ftf ^
'^4
89
• 17
1.279
109
284
37
/''.' ',
''•> V ", '
iil y t fffr
3.083
3.886
10.483
168
314
41
-'/','
4.386
6.484
12.621
168
314
41
'> J*%^,'o,c
4.366
B.4B4
12.620
33
37
-£•<£*
36
736
233
-------
Table 3b Site Surface Water and Treatment Plant Water Volume
133/1994 ENVIRONMENTAL ANALYSIS EUMMITVIUE SUPEDFUND SITE
OW (QAUON8I
lAMNt
IOCATION
MAY '(1
JUM'M
JUIVM
AUQ -
(W81 OCT'91 NOVM OtC'tJ JAN '94
MAH'M AFfT(4
MAY'94
JUN'M
(OAUON9I
17/91 IP 8/941
'low How
IOAUONI)
17191 TO 91(41
MUCH PHAM 8UMP
AUIYCINTtBOriAIN
I.eM.llO
1.461.400
J.I 14.080
1,611.760
1.878.400
1.189.440
3.024.OOO
3.301.360
1.188.710
1.821.400
3.114.800
3.389.800
8.6(1.480
1.141.440
8.891.480
1.61).760
OJ-f
lit t SUP
1,788.800
1.161.800
187.110
111.100
1I8.OOO
131.810
111.800
113.110
44.840
40.310
44.840
41.100
814.880
1.617.260
1.817.180
40.310
OS!
fO-l • ROAD 6IIP8
. 810.800
111.810
118.800
111.810
I18.8OO
89.180
178.880
848.710
848.710
88.180
Oil
KM 8. 8 COMBIHIO
I.II8.OOO
I.OIO.OOO
814.8811
818.380
818.400
880,310
111.480
141.810
111.100
118.000
448.400
840.000
814.880
118.000
HINCH DRAIN SUUf
fflUINTL _•
8.740.840
8.108.000
8.818.180
4.881.910
4.104.000
3.114.800
1.024.000
3.114.800
1.114.800
1.811.400
1.114,800
1,788.400
8.JB1.400
8.918.100
1.821.400
tAPttACHfAO
IRIAU»
V/r OVIBf tOW IB80-OOI
16.148.980 (.281.200 2.098.080
801.810
848.000
187.110
171.800
89.180
1.149.810
1.918.080
1.098.090
norsrwATt/1
'MATMtNT ft ANT)
4.811.110
1.188.800
7.888.840
8.998.400
7.898.840
1.198.800
ItftlACHAIl
INFLUINT TO COP)
18.818,180
11.111.800
10.111.180
18.188.140
17,910.400
14,891,360
19.118.800
18.814.980
18.018.000
18,038.710
18.818.720
18.888.100
11.817.780
31.400.000
14.881.360
11.817,780
MOt«aHOUNDWOH«l>IO»
0| 9.891.800 8.018,1001
I0| 10.138.400 8,01B.100|
1KIAUC
RtYNOtOS ADIT I«O 0>
1I.899.O40
11.161.800
17.766.710
11,142.0801 9.692,900
8.018,1001 8.140.800
4.130.080
1,018.684
181.660
105.011
144.080
1.496.860
17.766.710
144.060
MS
IBItNOlPS APIT TMATMtNTI
1.101,1(0
4.661.600
6.670.860
(.711.6101 10.136.400 6.016.1001 8.140.800
4.110.080
1.080.160
1.701.440
1.114.080
3.716.200
10.136.400
CIUHOU* fOKTAl
} %
18,471.180
24.884.240
BOrlY CMIK
H>J
tA8T Of t. O. 8UMH
1.160.840
1.109.800
96.160
111.100
66.400
(9.160
880.110
1.161.600
1.181.800
66.400
IMfMMH
IBOPSV CBiiK
119.116.100
108.148.600
16.701,610
14.667.160
10.114.600
4.641.660
1.980.600
1.767.680
1,111,180
1.461.610
1.810.140
1.644.600
60.086,440
105.611.160
I.46I.61C
SfffMMf
POHO 4 QISCHABOt
9.133.600
14.199,610
6.961.600
1.473.110
171.800
42.118.720
33.069.600
42,118.720
892.800 B.77I.B20
N/A
HI
OTHtH COMIBIlUTOm TO WIOMTMA
S7/HAUD
IUVtLANP CllffS
6.017.260
7.187.600
1,111.160
1709.110
1.848.800
1.619.910
1.416.800
1.881.680
4.868.760
7.146.604,
7.148.604
1.418.600
URIAH t
HOniH DUMP OHAINAOi
11.677.760
11.161.400
1.690 880
171.600
66960
11.1)6.860
13.884.600
13.684.800
SlfitAMO
CLAY OUt 8TOCK«H ISHf tl
1,187.360
1.881.100
1.891.680
1,791.930
1.783.920
1.691.66
MONTHIV TOIAl Of
CURMNT CONTRI8UTOM
167.489.280
191.608.000
46.346,120
38.488.800
19.006.000
3.844.800
188.618.384
1(8.618.384
1.461.61
MONIIIW TOTAl Of AU
rOTtMTIAt CONtKIIUTOM
110.198.400
144.361.400
64.770.710
76.668.000
61.603.100
64.170.640
41.011.600
40.488.480
18.497.864
19.678,810
19.006.431
39.699.290
177.919.040
119.688.084
138.866.064
19.979.91
nr-8.8 WICHTMAHrOM
-------
Table 4
Contaminant Content at High and Low Flows-
Identified AMD Streams
Streams ;v;;
Stream A :- Strata B Stream C Stream D Stream E StreanrF
High Flow
12/08/93
5/24/93
6/10^3
6/02OT
6/08/93
6OI2J93
Low Flow
9/08/93
12/16/93
5A3/93
11/05/93
9/2U93
6/10193
11/17/93
High
74.4
597.5
910
348
2S3
105
1176
Low
62.1
74
19
05
High
40
Low
28.61
63-W
15.4
1&6
54.75
65^3
Higft
1240
1738
636
.447J
2157.1
109^5
Low
438.1
793
368.4
310.3
7&38
800
High Flow
25J5
iNR
NR
OJ)17
•e.01
Low Flow
10.95
NR
NR
NR
Aluminum and Zinc Content at High and Low Flows
Identified AMD Streams
Streamr^-?.^.-^;-.^;*; ;•.•
; Recordfog'D*ter _; - -
High Flow
Low Flow
Zinc digested^-. ~.
High
Low
Aluoiii)iinc.di£.
High
Low
StreuvA;
-,;;•'..•
2C5W
15.98
43
StreamC
'•, • - (*.f. _.'.,^w
6^2m
5AJ1/94
101
64.1
1644
%7J
StrematD-
•.•.••".&••::••-:
6^(MM
5/D3/94
9.73
4J9
I54o
60.78
•Stremnt-E
-.'•' • '•' •'.•'
.Stream-E
" '*.^^
•: StreaorC. .
'• •; •••:•.-:
. Stream K
: V. '' ' .
Mo Infomunon Available
•-'.•
:.FB=C
. ,V-St
. rc-i*(l
6^ 1^4
. ;.^f
105
:--T:
992.1
All concentradoos - mg/l
NR - Not Recorded
-------
TablaB
COPPER CONCENTRATIONS AT WF-B.5
I I I I I I I I I I I I
24- 8- 29- 13- 29-11- 23- 7- 29- 14- 5- 16- 16- 6- 24- 15- 2- 21- 4- 2- 23- 20-
May- Jun- Jun- Jul- Jul- Aug- Aug- Sep- Sep- Oct- Nov- Nov- Dec- Jan- Jan- Feb- Mar- Mar- Apr- May- May- Jun-
93 93 93 93 93 93 93 93 93 93 93 93 93 94 94 94 94 94 94 94 94 94
Date
-------
I
0)
•o
I
TablaG
TOTAL CYANIDE CONCENTRATIONS AT WF-6.6
KM I I
24- 8- 29- 13- 29- II- 23- 7- 29- 14- 5- 16- 16- 6- 24- 15- 2- 21- 4- 2- 23- 20-
May- Jun- Jun- Jul- Jul- Aug- Aug- Sep- Sep- Oc|- Nov- Nov- Dec- Jan- Jan- Feb- Mar- Mar- Apr- May- May- Jun-
93 93 93 93 93 93 93 93 93 93 93 93 93 94 94 94 94 94 94 94 94 94
Date
-------
Standards, Requirements,
Criteria. Limitations
GROUNDWATER:
National Primary Drinking Water
Standards
National Secondary Drinking
Water Standards
Maximum Contaminant Level
Coals
Colorado Ground Water
Standards
Table 7
Potential Chemical Specific ARARs
Citation
40C.F.R. Part 141. SubpartB
pursuant to 42 U.S.C. §§ 300g-l
and 300J-9.
Slate: 5CCR 1003-1 pursuant to
C.R.S. § 25-M07(l)(x)
40 C.F.R. Part 143, pursuant to
42 U.S.C. §§ 300g-l(c) and 300j-
9
40C.F.R. Part 141, SubpartF,
pursuant to 42 U.S.C. § 300g-l
State: 5CCRI002-8
3.11.8
) 3.11.0-
Descrlntlon
Establishes numeric standards
for public water systems.
Maximum contaminant levels
(MCLs) are established to
protect human life-lime drinking
water exposure.
Establishes aesthetics-related
standards for public water
systems (secondary maximum
contaminant level).
Establishes drinking water
quality goals set at levels of no
known or anticipated adverse
health effects, with an adequate
margin of safety.
Establishes a scheme for
identifying groundwater
specified areas, for classification
of Colorado ground water and
provides numeric standards.
Also, establishes an interim
narrative standard for all
unclassified ground water,
supplementing statewide
standards.
Potentially Applicable or
Relevant and
No
No
No
Applicable
Comment
No public water supplies
are present, the State of
Colorado has
comprehensive ground-
• water classification system,
Including numeric standards
equivalent to (MCLs). See
section 3.2.1.
Protects aesthetic character.
not relevant to protection of
human health or
environment.
No non-zero MCLGs set at
levels less than MCLs were
identified for contaminants
of concern.
See section 3.2.1.
-------
Table 7 (continued)
Chemical Specific Criteria Tu-Oe-Considcrcd (TUC)
Standards, Requirements,
Criteria. Limitation!
RCRA Groundwaler Protection
Standard (RCRA GPS)
SURFACE WATER:
Colorado Water Quality
Standards
Citation
40 CFR§§ 264.92- 264.101
Stale: 6 CCR 1007-3
State: 5 CCR 1002-8, §§3.1.0-
3.1.17
Federal Water Quality Criteria 40 C.F.R. Part 131
Quality Criteria Tor Water, 1986,
pursuant to 33 U.S.C.§ 1314
Description
Potentially Applicable or
Relevant and Annronrlate
Establishes standards for ground > No
water quality related to RCRA
hazardous waste facilities.
Establishes standards and
classifications for Colorado
surface waters.
Sets criteria for surface water
quality based on loxicity to
aquatic organisms and human
health.
Applicable
Commenf
The Slate of Colorado has
comprehensive ground-
water classification system,
including numeric standards
equivalent to MCLs and
RCRA GPS.
See section 3.1.1.
Relevant and Appropriate See section 3.1.2.
AIR:
National Primary and Secondary
Ambient Air Quality Standards
National Emission Standards for
Hazardous Air Pollutants
40 C.F.R. Part 50, pursuant to 42
U.S.C. § 7409.
Slate: C.R.S. § 25-7-108. 5 CCR
1001-14.
40 C.F.R. Part 61, Subparts N, O,
P pursuant to 42 U.S.C. § 7412.
State: C.R.S. § 2S-7-108, 5 CCR
1001-10
Establishes standards for Applicable
ambient air quality to protect
public health and welfare
(Including standards for
paniculate matter and lead).
Sets emission standards for No
designated hazardous pollutants.
See section 3.4.
Air emissions are not
anticipated after
construction activities are
complete. See section 3.4.
-------
Table 7 (continued)
Chemical Specific Criteria To-Bc-Considcred (TDC)
Advisories to be
Cqn$ldcred and Guidance CJMlon. Descr)p(lpn To Be Considered Consent
SOILS:
Toxic Substances Control Act, PCD 52 FR 10688 April 2.1987 Establishes guidance cleanup Not considered There is no evidence that
Spill Cleanup Policy . levels for PCB contaminant PCB spills have occurred.
soils.
Interim Guidance on Establishing EPA Directive #9355.4-02, Established guidance cleanup Considered See section 3.3.
Soil Lead Cleanup Levels at September 1989. • levels for lead contaminated
Superfund Sites soils.
-------
Table 7 (continued)
Potential Action Specific ARARs
Potentially Applicable or
Relevant apd Appropriate Citation
SOLID WASTE DISPOSAL ACT f "SWDA"'!
Guidelines for (he Thermal
Processing of Solid Wastes
40 C.F.R. Part 240, pursuant to
42U.S.G. §6901.£LS£&
Guidelines for the Land Disposal of 40 C.R.S. Part 241, pursuant to
Solid Wastes 42 U.S.C. § 6901, £|_Sfi&
Colorado Regulations Pertaining to
Solid Waste Disposal Sites and
Facilities
Guidelines for the Storage and
Collection of Residential,
Commercial, and Institutional Solid
Waste
Source Separation for Materials
Recovery Guidelines
State: 6 CCR 1007-2. pursuant
toC.R.S. §30-20-101 and
C.R.S. §30-20-102,
40 C.F.R. Part 243, pursuant to
42 U.S.C.§ 6901,61583,
40 C.F.R. Part 246, pursuant to
42U.S.C. 6690l.etseq.
Description
Prescribes guidelines for
thermal processing of municipal
solid wastes.
Establishes requirements and
procedures for land disposal of
solid wastes.
Establishes requirements and
procedures for land disposal of
solid wastes and the siting of
disposal facilities.
Establishes guidelines for
collection of residential,
commercial, and institutional
solid wastes.
Establishes requirements and
recommended procedures for
source separation by federal
agencies of residential,
commercial, and institutional
solid wastes. .
Potentially Applicable or
Relevant and Appropriate
No
No
No
No
No
Comment
Thermal processing will not
occur.
Disposal of mine wastes
and closure of mines are
specifically addressed by
the Colorado Mined Land
Regulations. See section
4.2.
Disposal of mine wastes
and closure of mines are
specifically addressed by
the Colorado Mined Land
Regulations. See section
4.2
Not relevant.
Not relevant. Creates no
substantive cleanup
requirements.
-------
Table 7 (continued)
Potential Action Specific ARARs
Potentially Applicable or
Relevant and Appropriate
Guidelines for Development and
Implementation of State Solid
Waste Management Plans
Criteria for Classification of Solid
Waste Disposal Facilities and
Practices
Hazardous Waste Management
System: General
Identification and Listing of
Hazardous Waste
Standards Applicable to Generators
of Hazardous Waste
Citation
40 C.F.R. Part 256, pursuant to
42U.S.C. §6901,61584.
40 C.P.R. Part 2S7, pursuant to
42U.S.C.§690l,filS£Q1
40 C.F.R. Part 260
Slate: 6 CCR 1007-3 Part 260
40 C.F.R. Part 261, pursuant to
42U.S.C. §6921
Slate: 6 CCR 1007-3 Part 261,
pursuant to C.R.S. §25-15-302
Description
Establishes requirements for
federal approval of state
programs to regulate open
dumps.
establishes criteria for solid
waste disposal facilities and
practices.
Establishes procedures and
criteria for modification or
revocation of any provision in
parts 260-26S.
Defines those solid wastes
which are subject to regulation
as hazardous wastes under 40
C.F.R. Parts 262-26S and Parts
124,270,271.
40 C.F.R. Part 262, pursuant to
42 U.S.C. § 6922
State: 6 CCR 1007-3 Part 262,
pursuant to C.R.S. § 25-15-302
Establishes standards for
generators of hazardous waste.
Potentially Applicable or
Relevant and Appropriate.
No
No
No
Applicable
Applicable
Comment
Creates no substantive
cleanup requirements.
Disposal of mine wastes
and closure of mines are
specifically addressed by
the Colorado Mined Land
Regulations. See section
4.2.
Creates no substantive
cleanup requirements.
Provides for the
identification of hazardous
wastes; used to determine
disposal criteria for sludges
& spent process chemicals
generated from water
treatment.
If hazardous waste are
generated onsile and
managed offsite (he-
requirements are applicable.
Used to handle process
chemicals and sludge
management for water
treatment.
-------
Table 7 (continued)
Potential Action Specific ARARs
Potentially Applicable or
Relevant anil Appropriate
Standards Applicable to
Transporters of Hazardous Waste
Standards for Owners and
Operators or hazardous Waste
Treatment, Storage, and Disposal
Facilities
Interim Standards for Owners an
Operators of Hazardous Waste
Treatment, Storage, and Disposal
Facilities
Standards for the management of
Specific hazardous Wastes and
Specific Types of Hazardous Waste
Management Facilities
40 C.F.R. Part 263, pursuant to
42 U.S.C. § 6923
State: 6 CCR 1007-3 Part 263.
pursuant to C.R.S. § 25-15-302,
4 CCR 723-18
40 C.F.R. Part 264, pursuant to
42 U.S.C. § 6924,692S
State: 6 CCR 1007-3 Part 264,
subparts B, C, D, E, F. G, K, L,
and N, pursuant to C.R.S. §
25-15-302
40 C.F.R. Part 265
State: 6 CCR 1007-3. Part 265
40 C.F.R. Part 266
State: 6 CCR 1007-3, Part 267
Interim Standards for Owners and 40 C.F.R. Part 267
Operators of New Hazardous Waste
Land Disposal Facilities Stale: 6 CCR 1007-3, Part 267
Description
Establishes standards which
apply to persons transporting
hazardous waste within the U.S.
If the transportation requires a
manifest under 40 C.F.R. Part
262.
Establishes standards which
define the acceptable
management of hazardous waste
for owners and operators of
facilities which treat, store, or
dispose of hazardous waste.
Establishes standards for
management of hazardous waste
during interim status.
Potentially Applicable or
Relevant and Appropriate
Applicable
Yes
Relevant and Appropriate
Establishes requirements which No
apply to recyclable materials
that are reclaimed to recover
economically significant
amounts of precious metals,
including gold and silver.
Establishes minimum national No
standards that define acceptable
management of hazardous waste
for new land disposal facilities.
Commcpt
If hazardous wastes are
transported offsite the
requirements are applicable.
See section 4.1.
Establishes no substantive
standards applicable or
relevant and appropriate to
the IILP.
Not relevant to activities at
the site.
Part 267 regulations are no
longer effective after
February 13.1983.
-------
Table 7 (continued)
Potential Action Specific ARARs
Potentially Applicable or
Relevant and Appropriate
Hazardous Waste Permit Program
Underground Storage Tanks
dilation
40 C.F.R. Part 270
State: 6 CCR 1007-3. Part 100
40 C.F.R. Part 280
Descrlntion
Potentially Applicable or
Relevant and Annronrlate
Establishes provisions covering No
basic EPA permitting
requirements.
Establishes regulations related to No
underground storage tanks.
Comment
A permit is not required for
onsile CERCLA response
actions.
The use of or remediation
of underground storage
tanks is not anticipated.
-------
Table 7 (continued)
Potential Action Specific ARARs
Potentially Applicable or '
Relevant and Appropriate
SAFE DRINKING WATRR ACT
Underground Injection Control
Regulations
CLEAN WATRR ACT
National Pollutant Discharge
Elimination System
Amendment to the Settlement of
July 1, 1991
Effluent Limitations
Citation
40C.F.R. §§144.12.144.24,
and 144.25, pursuant to 42
U.S.C. § 121 (e)(l)
40 C.F.R. Parts 122,125
pursuant to 33 U.S.C. § 1342
5 CCR 1002-2, §§6.l.0lo
6.18.0, pursuant to C.R.S. § 25-
8-501
July 21,1992 agreement
between Co. Mined Reclamation
Board, Co. Mined Reclamation
Division, CO. Water Quality
Control Division, the Executive
Director of the CDPHE and the
SCMCI
40 C.F.R. Part 440, pursuant to
33 U.S.C. § 1311
5 CCR 1002-3, §§10.1 to
10.1.7, pursuant to C.R.S. § 25-
8-503
Description
Establishes requirements for
injection of waste water into
wells and aquifers.
Requires permits for the
discharge of pollutants from any
point source into waters of the
United Stales including
stormwater.
Establishes Numerical Criteria
Limits for water quality for
outfall 004 (WF5.5) an a
compliance plan
Sets technology-based effluent
limitations for point source
discharges In the Ore Mining
and Dressing Point Source
category. Also provides
exemption for release of storm
water where defined BMP
criteria are implemented.
Potentially Applicable or
Relevant and/Approprlqfe
No
Applicable
Comment
Underground injection is
not anticipated.
See sections 4.3 and 4.4.
Considered
Relevant and Appropriate See section 4.3.
-------
Table 7 (continued)
Potential Action Specific ARARs
Potentially Applicable or
Relevant an'! Appropriate
National Prelrealment Standards
Citation
40 C.F.R. Part 403, pursuant to
33U.S.C. § 1317
Description
Potentially Applicable or
Relevant and Annronrlatc
Toxic Pollutant Effluent Standards 40 C.P.R. Part 129, pursuant to
33U.S.C. §1317
Dredge or Fill Requirements
(Section 404)
Marine Protection, Research &
Sanctuary Act
40 C.F.R. Parts 230,231
33 C.F.R. Part 323, pursuant to
33 U.S.C. § 1344
13 U.S.C. §§ 1401-1445
Toxic Substances Control Act PCB 15 U.S.C. § 2605(c)
Requirements
Uranium Mill Tailings Radiation
Control Act
Surface Mining Control and
Reclamation Act
40C.F.R.Part76l
42 U.S.C. §§ 7901-7942
42 U.S.C. § 2022
30U.S.C. §§ 1201-1328
Sets standards to control No
pollutants which pass through or
interfere with treatment
processes in publicly owned
treatment works or which may
• contaminate sewage sludge.
Establishes effluent standards or No
prohibitions for certain toxic
pollutants: aldrin/dieldrin,
DDT, endrin, loxaphene,
benzidine, PCDs.
Requires permits for discharge No
of dredged or fill material into
navigable waters.
Regulates ocean dumping. No
Establishes disposal No
requirements for PCDs
Establishes requirements related " No
to uranium mill tailings.
Establishes provisions designed No
to protect the environment from
the effects of surface coal
mining operations.
Comment
No discharge to a publicly
owned treatment works is
anticipated.
The discharge of specified
pollutants is not anticipated.
No construction activities
are applicable involving
dredging in water treatment.
Ocean dumping will not
occur.
At this time it is not
anticipated that remedial
activities will involve the
disposal of PCBs.
Uranium mill tailings are
not present at the site.
Not relevant. Creates no
substantive cleanup
requirements.
-------
Table 7 (continued)
Potential Action Specific ARARs
Potentially Applicable or
[Relevant ami Appropriate Citation
Occupational Safety and Health Act 29 U.S.C. §§651 -678
Federal Mine Safely and Health Act 30 U.S.C. §§ 801-962
Hazardous Materials Transportation 49 U.S.C. §§ 1801-1813.
Act, D.O.T. Hazardous Materials 49 C.F.R. Parts 107,171-177
Transportation Regulations
Description
Regulates worker health and
safety.
Regulates transportation of
hazardous materials
Colorado Noise Abatement Statute State: CJtS. §§25-12-101, Establishes standards for
et seq, . controlling noise.
Colorado Mined Land Reclamation Slate: C.R.S. § 34-32-101
Act et seq. and regulations. 2 CCR
407-1
Potentially Applicable or
Relevant arid Appropriate
No
Regulates working conditions in No
underground mines to assure
safety and health of workers.
Applicable
No
Regulates all aspects of mining, Yes
including location of operations,
reclamation, and other
environmental and
socioeconomic impacts.
Comment
While not an ARAR, these
requirements will apply
during implementation of
remedies at the site.
While not an ARAR, the
requirements will be met if
it becomes necessary to
access underground mine
workings.
If hazardous materials are
transported offsite these
regulations will be attained.
Will apply to sludges or
spent or process chemicals
if determined hazardous.
While not an ARAR,
applicable standards will be
met during construction
activities at the Summitville
site.
See section 4.6.
-------
Table 7 (continued)
Potential Action Specific ARARs
Potentially Applicable or
Relevant and Apprpprlqte
Citation
National Historic Preservation Act 16 U.S.C. § 470
40 C.F.R. §6.301 (b)
Archeological and Historic
Preservation Act of 1974
Historic Sites Act of 1935,
Executive Order 11593
36 C.F.R. Part 800
Slate: C.R.S. §§24-80-101-108
16 U.S.C. §469
40C.F.R. §6.301 (c)
16 U.S.C. §§461 gt_sfi&
40 C.F.R. § 6.30l(a)
Description
EPA must account for the
affects of any action on any
property wilb historic,
architectural, archeological or
cultural value that is listed or
eligible for listing on the
National Register of Historic
Places, or the Colorado Register
of Historic Places.
Establishes procedures to
preserve historical and
archeological data which might
be destroyed through alteration
of terrain as a result of a federal
construction project or a
federally licensed activity or
program.
Requires federal agencies to
consider the existence and
location of landmarks on the
National Registry of Natural
Landmarks to avoid undesirable
impacts on such landmarks.
Potentially Applicable or
Relevant and Appropriate
Applicable
Applicable
Applicable
Comment
A survey will be performed
so that the Colorado State
Historic Preservation
Officer may determine if
parts of the site are eligible
for inclusion on the Stale or
National registers. (See
section 5.2).
A survey will be performed
to identify data that requires
protection during remedial
activities.
A survey will be performed
to identify potential natural
landmarks.
Colorado Wildlife Enforcement and
Penalties
Slate: C.R.S. §§ 33-1-101,
Prohibits actions detrimental to Applicable
wildlife.
During the design phase of
the remedy, consideration
will be given to the
protection of wildlife.
-------
Table 7 (continued)
Potential Action Specific ARARs
Potentially Applicable or
Relevant and Appropriate
Wildlife Commission Regulations
Citation
State: 2CCR405-0
Fish and Wildlife Coordination Act 16 U.S.C. §§ 661-666
40 C.F.R. § 6.302(g)
Endangered Species Act
16 U.S.C. §§1531-1543
50 C.F.R. Parts 17,402
40 C.F.R. § 6.302(h)
State: C.R.S. §§ 33-2-101,
et geq.
Coastal Zone Management Act
16 U.S.C. §§ 1451-1464
Pcscrlpllon
Establishes specific
requirements for protection of
wildlife.
Requires consultation when
federal department or agency'
proposes or authorizes any
modification of any stream or
other water body to provide for
adequate provision for
protection offish and wildlife
resources.
Requires that federal agencies
insure that any action
authorized, funded, or carried
out by the agency is not likely to
jeopardize the continued
existence of any threatened or
endangered species or destroy or
adversely modify critical
habitat.
Prohibits federal agencies from
undertaking any activity that is
not consistent with a state's
approved coastal zone
management program.
Potentially Applicable or
Relevant and Appropriate,
Applicable
Applicable
Applicable
No
Comment
During the design phase of
the remedy, requirements
for the protection of
wildlife will be met in the
Summitville Mine area.
Prior to modification of
water bodies appropriate
agencies will be consulted.
See section 5.1.
A survey of threatened and
endangered species is
underway. Prior to any
action that would jeopardize
the continued existence of
any threatened or
endangered species or
destroy or adversely modify
critical habitat, appropriate
State and Federal agencies
will be consulted. See
section 5.3.
The site is not in the
vicinity of a coastal zone.
-------
Table 7 (continued)
Potential Action Specific ARARs
Potentially Applicable or
Relevant *HI|
Wild and Scenic Rivers Act
Executive Order on Protection of
Wetlands
Executive Order on Floodplain
Management
CJlflUfflD.
16 U.S.C. §§ 1271-1287
40 C.F.R. § 6.302(e)
36 C.F.R. Part 297
Exec. Order No. 11,990
40 C.F.R. §6.302(b) and
Appendix A
Exec. Order No. 11,988
40 C.F.R. § 6.302(b) and
Appendix A
Rivers and Harbors Act of 1899, 33 U.S.C. §403
Section 10 Permit
33 C.F.R. Parts 320-330
pescrjpUon
Establishes requirements
applicable to water resource
development projects affecting
wild, scenic, or recreational
rivers within or studied for
. inclusion in the National Wild
and Scenic Rivers System.
Requires federal agencies to
evaluate the potential effects of
actions they may take in
wetlands to minimize adverse
impacts to the wetlands.
Requires federal agencies to
evaluate the potential effects of
actions they may take in a
floodplain to avoid, to the
maximum extent possible, the
adverse impacts associated with
direct and indirect development
of a floodplain.
Requires permit for structures or
work in or affecting navigable
waters.
Potentially Applicable or
Relevant and Appropriate.
Applicable
Applicable
Applicable
No
Comment
The site is not a wild,
scenic, or recreational river
in the National Wild and
Scenic River Systems. It
will be determined if any
part of the site is included
in the inventory of rivers
under consideration.
Wetlands will be
inventoried and considered.
Floodplains potentially
impacted will be
inventoried and considered.
Surface water of the
Summitvllle Mine Site are
not navigable within the
meaning of Section 10 of
the Rivers and Harbors Act
of 1899.
-------
TableS
Numeric Surface Water Quality Goals and AJRARs
AJamosa River - Monitoring Station AR-45.4
METAL
PH
^^^
Aoemciott
Cadmian.cfa.oae
OwmeVLctanne
Copper, CflroniC
Cyuride
Iron* chronic
L^chnmc
MugneB, chronic
Mercury* chionic
Nickd. chrwuc
Suvcr* cflrooic* Lwwi
ZjnCi chraoic
SURFACE WATER QUALTTY COALS
. OasslfTVS)
6J-9.0
RTuu/l diccnhfHL MKV 1 thumoti ^MVmntvr 10 onhr F*» tMlaww nf
yor Ghrooc • Acute TVS « 730ugfl dissolved
50cg/lnx^recoveraWc.I-diy
2Jo^n dissolved @ 250oi^l Mfttoess
1 lug/1 dissolved
jOu^rl dissoivcdt b>sed upon 85t& petceotuc ^fppi*™ dt& 000 f*|pr*n*
3«
Sug/L l-d«y
1408/1 disSDl««l@250m^h«teS5
lOOOug^L dissolved
O.Olus/L tool recovenfale
192ug/l dissolved @ 2SOtng/l hudaess
0 J6usj/l dtssoivcd @ 250ni9/l hudocss
230ng/I dissohwd (g 250mg/l hudnes
Note: Based upon WQCD finding of 250mg/l hardness.Reservoir.
-------
Table 9
Evaluation of Alternatives
CtttCOA
Overall
PVUCCCOOQ 01
•odtfao
FiHyWIHIflgllf
f*/i«npliaiyi»» mith
ARARs
toog-eenn
Reduction of
Toxtoty,
mobility, or
voltnnc
Shoft-tenn
cflemivBoess
fonlaMmfaJlity
CMC
Toul Capital
Aamti
TfBtiiiu HI and
Amiuiiiiiii
Present Worth-
Alternative I
No Acfluo
No
No
Low
No tzcsmcnt of
sowcesof
MMfMIWfWtUlfV
Low
E»y
S 270^)00
s o
S 270,000
AtenativeZ
Water Titttncat
No
Yes
Low
AOUfCGSOf
High
Moderate
S 290,000
S 9,700^00
S«6,000^00
Atenanve3
Ruuuvil to Mine
Ww
Yes
Yes
High
Mfl HMtMHMHI* 1*f
sources of
-jm m JH j miijiii
High
Eisy
123^00,000
S 900.000
s«uooux»
Aitcuuuvc4
Cnpqr Valley Adit
T>«tm
Ye»
Yes
MoojcntB
No tmoiicntof
sources of
annummfum
High
Moderate
S 27400,000
S 1,400,000
$56,400,000
AUBUUUVCt '
CropsyOiinif 1
TVtmor
Yes
Yes
MJDQUittB
No HBxtncui of
sonccsof
High
raodenBB
526^00,000
S 900,000
$46,800^)00
The present we
mfiv Alteraative#2isb3se
-------
ENLARGED AREA MAP
ENVIRONMENTAL CHEMICAL
CORPORATION
-------
-------
B
FIGURE J
Ccologr
Cropiy Valttjr.Sulloa
c a R r o * A T i o .•
-------
•tf^'- \
t I ^^—*
+v •«• . • V.\
»ll» II Ji»ll *.•»«,
UIHC rOOIFRINf
SURrACC StCflACC WAIW
StRLUI AND OIRCCIICN Cf RCW
CeatamloiKi) Surfm
WiiirSlruai
-------
MONTS VISTA NATIONAL W1LDUFB RSFUCS
AIAIIOSA NATIONAL
AQUATIC LIFE COLD 2
RECREATION?
| A JAR A
£BBK
AQUATIC UFEWMU a
SfCUFMT 3b
AIJkUQSA
AQUATIC UFt COD I
KHI
•ml
KMIl I* • • Mill
SummltviUe Mint Site
Alimoia River Stream
Se(mcnt ClMilfleatloni
COBfORATIO.N
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