United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R06-91/067
September 1991
&EPA Superfund
Record of Decision:
Cimarron Mining, NM
X,
t
I
-------
0272-101
REPORT DOCUMENTATION i. REPORT NO. 2.
PAGE EPA/ROD/R06-91/067
4. TWe and Subtitle
SUPERFUND RECORD OF DECISION
Cimarron Mining, NM
Second Remedial Action - Final
7. Author)*)
». Performing Organization Name and Addreu
12. Sponsoring Organization Name and Addreaa
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
3. Recipient's Acceaalon No.
5. Report Date
09/06/91
6.
8. Performing Organization Rept No.
10. ProjecVTaak/Work Unit No.
1 1. Contracted or Grant(G) No.
(C)
-------
EPA/ROD/R06-91/067
Cimarron Mining, NM
Second Remedial Action - Final
Abstract (Continued)
sediment and soil contaminated with high concentrations of metals, particularly lead at
the Sierra Blanca location. A 1990 ROD addressed contamination of the original
Cimarron mill, as OU1. This ROD addresses the final remedial action of the soil and
waste piles at the Sierra Blanca mill location, as OU2. The primary contaminants of
concern affecting the soil, sediment, debris, and sludge are metals including arsenic
and lead.
The selected remedial action for the site includes excavating and treating onsite 225
cubic yards of contaminated material piles and tank sediment, including cinder block
trench sediment which failed the TCLP test, using cement solidification and
stabilization; excavating and disposing of 345 cubic yards of contaminated surficial
soil and sludge that did not fail the TCLP test in an onsite discharge pit along with
the solidified/stabilized waste; capping the discharge pit with an impermeable cover/-
removing all process drums, and decontaminating tanks and associated piping onsite;
filling in the discharge pits and the cinder block trench with onsite soil and covering
with clean fill; installing additional ground water monitoring wells; monitoring ground
water; and implementing institutional controls including deed restrictions, and site
access restrictions including fencing and zoning ordinances. The estimated present
worth cost for this remedial action is $79,000, which includes a total present worth
O&M cost of $10,000.
PERFORMANCE STANDARDS OR GOALS: Chemical- and action-specific soil clean-up goals for
lead are based on the "Interim Guidance on Establishing Soil Lead Clean-up Levels at
Superfund Sites", and remediation levels will not exceed lead 500 mg/kg.
-------
Decision Summary
Cimarron Mining Corporation Site
Operable Unit 2 (Sierra Blanca)
Record of Decision
September 1991
-------
DECLARATION FOR THE RECORD OF DECISION
CIMARRON MINING CORPORATION SITE
OPERABLE UNIT 2 (SIERRA BLANCA)
CARRIZOZO, NEW MEXICO
Statutory Preference for Treatment as a
Principal Element is Met
and Five-Year Review is Not Required
SITE NAME AND LOCATION
Cimarron Mining Operable Unit 2 (Sierra Blanca)
Carrizozo, Lincoln County, New Mexico
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for
the final operable unit of the Cimarron Mining Corporation site in
Carrizozo, Lincoln County, New Mexico, which was chosen in
accordance with the Comprehensive Environmental Response,
Compensation and Liability Act of 1980 (CERCLA), as amended by the
Superfund Amendments and Reauthorization Act of 1986 (SARA) and,
to the extent practicable, the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP).
This decision is based upon the contents of the administrative
record file for the Cimarron Mining Corporation site.
The United States Environmental Protection Agency and the New
Mexico Environment Department (NMED) agree on the selected remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action selected
in this Record of Decision (ROD), may present an imminent and
substantial endangerment to public health, welfare, or the
environment.
DESCRIPTION OF THE SELECTED REMEDY
This final remedy addresses remediation of soil and waste pile
contamination at the Cimarron Mining Corporation Operable Unit 2
(Sierra Blanca) mill location. The principal threats posed by the
site will be eliminated or reduced through treatment and
engineering controls.
The major components of the selected remedy include:
-------
o Solidification/stabilization of contaminated soils and waste .
piles exceeding 500 ppm lead and onsite disposal.
o Ground Water Monitoring
- Install two additional ground water monitoring wells.
- The ground water sampling program, to be developed in the
Operation and Maintenance Plan, may be amended and/or eliminated
if data confirms effective remediation of the site has occurred.
In addition to the soils and waste pile remedy, the following
measures will be implemented:
o Removal of the process chemical drums, and decontamination of
tanks and associated piping;
o Filling in the discharge pits and cinder block trench with
onsite soils and covering with clean fill;
o Inspection and maintenance of the existing fence.
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that are
legally applicable or relevant and appropriate to the remedial
action, and is cost-effective. This remedy utilizes permanent
solutions and alternative treatment technologies (or resource
recovery) to the maximum extent practicable and satisfies the
statutory preference for remedies that employ treatment that
reduces toxicity, mobility, or volume as a principal element.
Because this remedy will not result in hazardous substances
remaining onsite above health-based levels, a five-year review of
the remedial action is not required.
Robert E. Layt6n Jr., P.E. Date
Regional Administrator
U.S. EPA - Region 6
-------
Table of Contents
Page
I. Location and General Description 1
II. Site History and Enforcement Activities 1
Figure 1 - Site Location Map 2
Figure 2 - Site Map 4
III. Community Participation
IV. Scope and Role of the Operable Unit 6
V. Site Characteristics 7
Figure 3 - Estimated Extent of Areas Requiring
Remediation 8
Figure 4 - Estimated Extent of Soils and Waste
Piles Exceeding 500 ppm lead 10
VI. Summary of Site Risks 11
Table 1 - Risks from Ingestion of Compounds in Soil . 13
Table 2 - Risks from Dermal Contact with Chemicals
in Soils 14
.Table 3t - Risks from Inhalation of Dusts 15
Table 4 - Metals Detected at Elevated Concentrations
by Media 17
Table 5 - Oral Reference Doses for Contaminants of
Concern 18
Table 6 - Carcinogenic Slope Factors for Contaminants
of Concern ................ 19
Table 7 - Summary of Risks Associated with Potential
Future Exposure 22
VII. Description of Alternatives 23
VIII. Summary of Comparative Analysis of Alternatives . . 26
IX. Selected Remedy 32
X. Statutory Determination 32
XI. Documentation of No Significant Changes 33
XII. Responsiveness Summary 34
Community Preferences 34
Integration of Comments 34
Attachment 1 - Integrated Uptake/Biokinetic Modelling
Attachment 2 - Identification and Evaluation of Remedial
Action Requirements
-------
Decision Summary
Cimarron Mining Corporation Site
Operable Unit 2
Record of Decision
I. LOCATION AND GENERAL DESCRIPTION
The Sierra Blanca milling location near Carrizozo, New Mexico,
has been identified as an Operable Unit (OU) 2 of the Cimarron
Mining Corporation Superfund site as a result of contamination
of soils with arsenic and metals. The facility, which is no
longer operating, utilized precious metal extraction processes
which resulted in unpermitted discharge of contaminated
liquids, and the stockpiling of approximately 570 cubic yards
of contaminated materials piles and other waste sediment.
Ground water is not contaminated and no surface water exists
near the site. The site is 7.5 acres in size, relatively
flat, and is located in T8S, R10E, Section 11, east of U.S.
Highway 54 (Figure 1). Figure 1 shows the location of both
mill sites (i.e. Operable Unit 1 and Operable Unit 2), and
their relative positions to each other and the town of
Carrizozo, which has a population of approximately 900. One
resident is located directly adjacent to the site and the
primary residential population is approximately 1/2 mile
north/north-west of the site. Access to Sierra Blanca is
restricted by a barbed-wire fence and locked gates.
II. SITE HISTORY AND ENFORCEMENT ACTIVITIES
The Sierra Blanca Facility is an inactive mill originally
owned by Scott-Tex, Inc., and used to recover a variety of
metals from ores transported to the site. The mill
temporarily shut down in the early 1970's, and the Town of
Carrizozo eventually became owner of the site. In 1979, the
site was leased under the name of "American Minerals Recovery
Corporation." Notes acquired from the laboratory in the main
on-site processing building indicate that the facility
operators were attempting to recover silver from various ore
materials. It has been reported that the operators claimed
that platinum was also recovered from the ore material. An
New Mexico Environment Department (NMED) site inspection
report prepared on 11/18/80 states that "this operation
extracts whatever there is a market for - one week gold, the
next silver, platinum and so on."
The Sierra Blanca mill was designed and operated similarly to
the Cimarron mill with the exception that cyanide was
apparently not used at Sierra Blanca. For a short period of
time, the two mills were apparently operated concurrently and
by the same people. EPA and NMED site file information
discusses a possible spill at Cimarron which prompted milling
operations to be relocated to Sierra Blanca in June of 1982.
-------
5500-
Source: USGS. Cub Mountoin 7.5' Quod.. 1961. Corrfaozo Eott. Conizozo W«t. * Church Mountain 7.5' Quads.. 1982.
RGURE 1
SfTE LOCATION MAP
SIERRA BLANCA OPERABLE UNIT
CARRIZOZO, NEW MEXICO
NEW
MEXICO
-------
The Sierra Blanca milling location includes two buildings,
four discharge pits, one cinder block trench, a septic tank
system, and numerous process tanks and materials piles.
A 1975 U.S. Soil Conservation Service aerial photograph (USDA,
SCS, 1983) shows that the site included only a single building
(Process Building 1), and no discharge pits and only a few
materials piles in 1975. Sometime between 1980 and 1984,
discharge pits, process tanks, and more materials piles were
added.
An NMED memo dated March 6, 1980, states that there were two
buildings at the site, each owned by a different individual.
According to the memo, the southern building (Process Building
1) was owned by Sierra Blanca Mining and Processing Co. and
housed operations consisting of mechanical separation of gold
from its natural ore. The ore material was reportedly from
the Jicarilla Mountain area in south-central New Mexico. The
southern building (Process Building 2) was owned by Double
Eagle Mining Co., which planned to chemically extract gold
from ore. The memo indicates that this ore was transferred
from the Cimarron site. The memo states that Double Eagle
Mining Co. maintained extraction equipment both inside and
outside of the northern building.
A February 1985, NMED Site Inspection Report described the
site as an "abandoned ore-processing mill with 2 lined
impoundments, an underground storage tank, 2 above ground
tanks and a small unlined pit." The lining in the
impoundments was noted to be torn. The actual on-site
inspections were performed in April, May, and June, 1984.
Subsequent investigations performed by CDM-FPC under contract
to EPA have resulted in the identification of contaminated
materials above health based levels.
It should be noted that portions of the facility have been
dismantled, sold, moved, and/or removed. The current site
features are shown on Figure 2. The material pile locations
and outlines are approximate.
The extensive RI field work and feasibility study began in May
1990 and was completed in June 1991. The data generated was
used to estimate the extent and magnitude of contamination at
the Cimarron Mining site and to develop and review remedial
alternatives. The alternatives evaluated included various
treatment alternatives for the soils and waste piles,
institutional controls, and no action.
-------
7r
MP\23 MP-20-, U
MP-21 MP-J8 BUXX
NOTE: 10CAT10NS AND DIMENSIONS OF
MATERIAL PILES. TANKS. AND MILLING
EQUIPMENT ARE APPROXIMATE.
LEGEND
cO
MATERIAL PILE LOCATION
MP-00 MATERIAL PILE DESIGNATION
FENCE
CMP-2
MP-03
FIGURE 2
SITE MAP
-------
III. COMMUNITY PARTICIPATION
Community interest in the Cimarron Mining site has been
relatively high due to the close proximity of the site to the
town of Carrizozo.
Major community interest has focused on alleviating the stigma
of a hazardous waste or Superfund site as it relates to the
community and the desire to have an expeditious solution to
allow future industrial development of the site.
A public "open house" workshop was conducted in May 1989 to
inform the community of the general RI/FS activities planned
and the Superfund process and to answer any questions.
Approximately 35 people attended, including out-of-town
individuals and representatives of the local newspaper and the
New Mexico Bureau of Mines.
Questions and comments ranged from concerns regarding the
level of site contamination, potential impacts on the
community and possible solutions to a disregard for the
previous analytical data from the site and an unwillingness
to accept the potential of long term impacts from the site
* contamination.
In March 1990, a second public workshop, primarily for
Cimarron Operable Unit 1, was conducted to notify the
community of the preliminary RI results and to answer
questions. Approximately 25 people attended this workshop.
Most questions evolved around potential remedial solutions and
the schedule of future activities. A major portion of the
meeting involved discussions of the Cimarron Operable Unit 2
(Sierra Blanca) site and the responsible party status of the
town of Carrizozo, which leased the property to the operators
of the mill.
Numerous informal status briefings have been conducted with
various interested citizens and local officials including
presentations, by invitation, at the local chapter of the
Rotary Club.
The public participation requirements of CERCLA sections
113(K)(2)(B)(i-v) and 117 have been met. The RI/FS documents
for the Cimarron Mining Operable Unit 2 (Sierra Blanca) site
and a Proposed Plan of Remedial Action were released for
public comment in June 1991. Public notices were published
in the Lincoln County News. fact sheets were mailed to
interested individuals, and the documents were made available
for review in local repositories. A public meeting to discuss
the Proposed Plan was conducted on June 17, 1991.
-------
Approximately 15 people attended the public meeting. Most
comments (from 2 commentors) on the proposed plan of
solidification/stabilization and onsite disposal focused on
the potential for off site disposal of the treated soils. No
comments were presented which adamantly opposed the
solidification and on site disposal alternative. Officials
representing the Town of Carrizozo also had no comment
regarding the proposed remedy.
The responsiveness summary presented on page 21 provides
further details regarding the comments received at the public
meeting. No additional comments were received during the 30
day public comment period, which ended on July 10, 1991.
IV. SCOPE AND ROLE OF THE OPERABLE UNIT
The Cimarron Operable Unit 2 (Sierra Blanca) RI/FS has been
performed in accordance with EPA's National Contingency Plan
under the Comprehensive Environmental Response Compensation
and Liability Act (CERCLA), and the Superfund Amendments
Reauthorization Act (SARA). This will be the final operable
unit for this site.
The overall objectives of the RI/FS are:
o To collect and evaluate data to determine the extent of
surficial contamination at the site.
o To collect and evaluate data to determine if subsurface
^ contamination has occurred in either the soils or ground
water.
o To collect and evaluate data to characterize the shallow
subsurface geology and hydrogeology.
o To determine if ground water from nearby residential wells
has been affected by site activities.
o To evaluate human health and environmental risks posed by
site-related contamination identified during the RI.
o To identify potentially applicable or relevant and
appropriate regulations (ARARs) for response actions.
o To identify and evaluate remedial alternatives to address
human health and/or environmental risks.
Based on the evaluation of the milling process, findings of
previous investigations, and results of the RI field
investigation, the sources and the areas of environmental
contamination at the Sierra Blanca site have been delineated.
-------
The remedy outlined in this Record of Decision represents the
final remedial action at the site and will address the
principal threats which are posed by the lead contaminated
soils and materials piles.
V. SITE CHARACTERISTICS
In contrast to the Cimarron site, the Sierra Blanca property
is not contaminated with cyanide. At Sierra Blanca, the
ground water has been found to be unaffected by past site
operations; but some soils, tank sediments, discharge pit
sediments, and waste pile soils contain high concentrations
of various metals, particularly lead. Typical background
concentrations of lead in the area average approximately
13 ppm (parts per million), whereas onsite concentrations
range as high as 46,400 ppm.
EPA has issued a directive establishing interim soil cleanup
levels of 500-1000 ppm lead at Superfund sites (OSWER
Directive 19355.4-02, EPA, 1989). These levels represent safe
onsite levels assuming either a residential or industrial
future use, respectively. EPA has established 500 ppm as the
most appropriate soil level for this site. This is a
conservative level in that it assumes future residential use
of the property.
Figure 3 depicts the areas of the Sierra Blanca property which
are contaminated with lead concentrations above 500 ppm.
Other metals besides lead are also found at elevated
concentrations at the site. These elements are arsenic,
barium, beryllium, copper, lead, manganese, mercury, silver,
and zinc. Lead, however, represents the most significant
threat to human health; and therefore lead is considered the
principal threat at the site. The cleanup of these other
compounds will be incidental to the lead cleanup.
Based on the results of the RI, approximately 43 cubic yards
of tank sediments, 182 cubic yards of material pile soils and
rock, and 345 cubic yards of discharge pit sediment and site
soils are contaminated with lead at levels above 500 ppm.
Referring to Figure 3, for the tank samples analyzed for lead,
the maximum on-site lead concentration is 46,400.0 ppm. Seven
tanks (TS-01-TS-07) contained lead at concentrations above 500
ppm. The average concentration of lead in all tanks sampled
is 12,049 ppm.
Lead in the various waste piles on site has a maximum
concentration of 18,900.0 ppm. The contaminated waste piles
are MP-01, MP-02, MP-03, MP-26, and MP-32. In contrast to the
-------
PROCESS
BLDG. 1
INSET
LEGEND
J WASTE MATERIAL WHICH PASSED TCLP
U WASTE MATERIAL WHICH FAILED TCLP FOR LEAD
-X— SITE BOUNDARY
MP ORE PILE
TS TANK
SS CONTAMINATED SOIL
FIGURE o
ESTIMATED EXTENT OF AREAS WITH
LEAD CONCENTRATIONS GREATER THAN 500 PPM
-------
tank sediments, where the majority of samples indicate high
elevated concentrations of lead, only four of the 34 waste
pile samples analyzed indicate contamination with lead at
levels in excess of the 500-1000 ppm guidance levels. Two
piles, MP-01 and MP-26, with lead concentrations of 18,900 ppm
and 18,700 ppm, respectively, are the only piles that
demonstrate significantly elevated lead levels. All other
waste pile samples contain lead at concentrations of 114 ppm
or less.
The maximum level of lead in surface soils at the site is
10,409 ppm, with an overall average concentration of 1470 ppm.
Although surface soil and waste pile samples collected at the
site indicate highly elevated concentrations of lead in some
areas, the contamination has been found to be limited to 6"
to 18" in depth. The contaminated soils areas are shown in
Figure 2 as SS-02 and SS-05.
It is important to note that the various types of contaminated
material at the site differ in physical characteristics. The
materials vary considerably with respect to particle size.
The tank sediments, discharge pit sediments, and site soils
consist of fine particle size soils, whereas the material in
the material piles ranges in size from soil particles to
boulder size rocks. The materials also vary with respect to
their leaching potential.
As part of the sampling program, select samples were analyzed
using Toxicity Characteristic Leaching Procedure (TCLP) for
the elements of concern: arsenic, barium and lead. The TCLP
analysis is a procedure for evaluating a material's ability
to release contaminants to the environment. The samples were
chosen to be representative of contaminated tank sediments,
surface soils, material piles, and discharge pit sediments.
Only the samples of tank sediments and material piles failed
the TCLP test for lead. All of the samples passed the TCLP
test for arsenic and barium.
This indicates that the metals present in soils and discharge
pit sediments are tightly bound within the soil and that
migration of arsenic and the metals of concern from discharge
pit sediments and contaminated surface soils to deeper soils
and groundwater is not likely to occur. However, lead in the
material piles 1, 2, 3, 26, and 32, as indicated in Figure 4,
does have the potential for such migration via leaching. If
tanks were spilled or dispersed on the ground, lead migration
could also occur.
-------
LEGEND
MATERIAL WTTH LEAD CONCENTRATIONS
GREATER THAN 500 PPM
FIGURE 4
ESTIMATED AREAL EXTENT OF ELEVATED METALS CONCENTRATIONS
IN SURFACE SOILS. DISCHARGE PIT SEDIMENTS, & MATERIAL PILES
-------
With respect to the remedial action at Sierra Blanca, the TCLP
results help to direct the cleanup. Those materials which
fail the TCLP test will have to undergo more stringent
treatment to control potential migration of contaminants than
those materials which pass the test. In accordance with EPA
Publication 9347.3-12FS dated January 1991, titled "Superfund
Guide to RCRA Management Requirements for Mineral Processing
Wastes," mineral processing waste is subject to hazardous
waste regulations under RCRA Subtitle C if it meets the
definition of a RCRA hazardous waste (i.e. a listed waste or
exhibits a characteristic, as in failing the TCLP test).
Alternative remedial approaches to the Sierra Blanca waste
materials are further discussed below in this Decision Summary
and in the Feasibility Study for Sierra Blanca.
VI. SUMMARY OF SITE RISKS
The objective of the Risk Assessment was to determine whether
or not the substances present at the Sierra Blanca site
present potential human health risks. Risks were evaluated
by incorporating Sierra Blanca, or Operable Unit 2 (OU2)
contaminant concentration data into tables previously
developed for the risk assessment portion of the Cimarron
(OU1) RI/FS. This data table is used due to the similarity
of contaminants and the geographical proximity of the two
sites. Media evaluated included surface soil, material piles,
discharge pit and tank sediments, and ground water. The Risk
Assessment evaluated the potential cancer and noncancer health
risks associated with incidental ingestion of soils from the
site, dermal contact with soils from the site, and inhalation
of windblown dust containing site-related contaminants.
Groundwater is not evaluated since the groundwater has been
found to not be contaminated with site related contaminants
of concern.
Baseline Risk
Due to the lack of an accepted oral reference dose (Rfd) for
lead, the primary contaminant of concern at Sierra Blanca, it
is difficult to quantify the current baseline risks. However,
any exposure to elevated concentrations of lead can
potentially result in elevated blood lead levels, particularly
in children.
At the present time there are no final regulatory standards
for lead in soils. As previously stated, EPA has issued a
directive establishing interim soil lead cleanup levels of
500-1000 ppm at Superfund sites (OSWER Directive #9355.4-02,
11
-------
EPA, 1989). These levels represent safe onsite levels based
on acceptable inhalation/ingestion risks, assuming either a
residential or industrial future use, respectively. EPA has
established 500 ppm as the most appropriate soil level for
this site. This is a conservative level in that it assumes
future residential use of the property.
EPA currently suggests the use of a computer model, referred
to as the Uptake Bibkinetic Model, for helping to verify or
refine cleanup goals. This model was used taking into
consideration all potential sources (air, soil, water, etc.)
of lead exposure with regards to site specific aspects of the
Sierra Blanca mill and the Carrizozo area, for generating a
safe level. The results of this modeling (Attachment 1)
indicate that a 500 ppm lead cleanup level is safe and
appropriate.
Actual or threatened releases of hazardous substances from
this site, if not addressed by implementing the response
action selected in this Record of Decision (ROD), may present
an imminent and substantial endangerment to public health,
welfare, or the environment.
Exposure Assessment
A degree of conservatism is built into the risk calculations
in several areas. First, all exposures evaluated are for a
hypothetical future on-site population. Assumptions in the
exposure evaluation include residential development on the
contaminated site, 30 years of residence at that location, and
that every day during that period is spent on the site. As
described in the OU1 RI report the evaluation of surface soils
assumes that soil to which ingestion or dermal exposure occurs
contains all site-related contaminants at the maximum level
detected in surface soils. Because contaminant concentrations
vary at different locations at the site and exposure to
maximal concentrations for all contaminants by one individual
is unlikely, this overestimates any combination of exposures
that could actually occur at the site and maximizes the risk
estimates generated by the risk calculations. This approach
is regarded by EPA as sufficient to characterize risks in this
level of analysis. If such as evaluation indicates that
contaminants from the site do not present an appreciable
health risk, even under these "worst case" exposure
assumptions, it can be assumed that exposures associated with
more plausible exposure scenarios are also without appreciable
risks. Tables 1, 2, and 3 present the calculations and
parameters used to estimate ingestion, dermal absorption, and
inhalation exposures in this assessment.
12
-------
TABLE 1
RISKS FROM
INGESTION OF COMPOUNDS IN SOIL
Lifetime Cancer Risk « [ LJfJJ^Jj^osurJ* ]*tCancer P°tency Factor]
CS X IR X CF X FI x EF X ED
Hazard Index = [Daily Exposure] * [Reference Dose]
. f CS X IRCF x FI + [RfD]
where:
CS « concentration of chemical in soil (mg/kg) - compound specific
IR * ingestion rate (mg soil/day) = 200 for child; » 100 for adult
CF - conversion factor (10~6 kg/mg)
FI « fraction ingested from contaminated source = 100%
EF - exposure frequency (days/yr) = 1, current? = 365, future
ED = exposure duration (years) = 1, current; = 30, future
AT - averaging time (days) = 25,550
BWt = average lifetime bodyweight (kg) = 70 kg
BWT = bodyweight at time of exposure (kg) = 15 kg (child)
CPF = cancer potency factor (mg/kg-d)"1 - compound specific
RfD = reference dose (mg/kg-d) - compound specific
-------
Toxicity Assessment
The Hazard Quotient (HQ) approach to evaluation of potential
health risks assumes that there is a level of exposure below
which it is unlikely for even sensitive populations to
experience adverse health effects. If the HQ exceeds unity
(1), there may be concern for potential systemic effects. As
a rule, the greater the HQ above unity the greater the level
of concern. To assess the overall potential for noncancer
effects posed by exposure to multiple chemicals, a Hazard
Index (HI) approach has been developed based on EPA's
"Guidelines for Health Risk Assessment of Chemical Mixtures".
This approach assumes that simultaneous subthreshold exposures
to several chemicals could result in an adverse health effect.
The HI is equal to the sum of the HQs. When the HI exceeds
unity, there may be concern for potential health effects. It
should be noted that not all substances present on the site
act on the same target organ or produce the same adverse
health effect. Therefore, summation or the HQs to generate
a HI is a conservative estimate of risk.
A review of the data indicates that the contaminants of
concern (COCs) at Sierra Blanca are similar in surface soils,
materials piles, and tank sediments. The major COC is lead;
however, arsenic and other metals are present in conjunction
with lead at various locations on the site. The elements
evaluted in the risk assessment are arsenic, barium,
beryllium, copper, lead, manganese, mercury, silver, sodium
and zinc. COCs include all of these, with the addition of
sodium. Tank sediment COCs include all those found in soil,
with the exception of beryllium. COCs in ground water consist
of lead, manganese, and zinc. Table 4 shows all substances
detected and indicates which substances were found at elevated
levels, by media. The Reference Doses (RfDs) available for
COCs at Sierra Blanca are listed in Table 5. The Reference
Doses (Rfds) for the COCs at this site exist only for
evaluation of ingestion exposures. No RfD values are
currently available for evaluation of inhalation or dermal
exposures to these COCs. As in the risk assessment for OU1,
oral RfDs are used to evaluate potential health risks
following dermal absorption of substances. This approach
assumes that systemic toxicity is similar following absorption
via the skin or gastrointestinal tract. This approach was not
used for inhalation exposures in the OU1 assessment or in this
report, as toxicity via this route is frequently specific to
the respiratory tract.
Two of the COCs (arsenic and beryllium) are identified as
known or suspected human carcinogens. These are listed in
16
-------
TABLE 2
RISKS FROM
DERMAL CONTACT WITH CHEMICALS IN SOIL
Lifetime Cancer Risk - orbedose x[Cancer Potency Factor]
f CS X CF X SA X LR X ABS X EF X ED
"I BWX X AT
Hazard Index -= [Daily Absorbed Dose] + [RfD]
- I" CS X CF X SA K LR X ABS j + [RfD]
here:
CS « concentration of chemical in soil (ing/kg) - compound specific
CF * conversion factor (10"6 kg/mg).
SA - surface area of skin available for contact (cm2/event) « 2,100
cm2 child; = 5,300 cm2 adult
LR «• loading rate of soil on skin (mg/cm2) » 0.5 mg/cm2
ABS - absorption fraction (unitless) « 1%
EF = exposure frequency (events/year) = 1/yr for current scenario;
= 260 ages 1-5 (5 times/wk), 104 thereafter (2 times/wk) for
future.
ED = exposure duration (years) = 1 current; = 30 future
BWt = average lifetime body weight (kg) = 70 kg
BWT = bodyweight at time of exposure (kg) = 70 kg adult; = 15 kg
child
AT = averaging time (days) = 25,550
CPF = cancer potency factor (mg/kg-d)"1 - compound specific
RfD = reference dose (mg/kg-d) - compound specific
-------
TABLE 3
RISKS FROM
INHALATION OF DUSTS
Lifetime Cancer Risk
CD X CF. X CF-X RD X ED X WF
AT
X [URF]
where:
CD
CF,
CF2
RD
ED
WF
AT
URF
concentration of contaminant in dust (mg/kg) - compound specifi
conversion factor #1 (103 /ig/mg)
conversion factor #2 (10*9 kg/jig)
concentration of respirable dust in air (/*g/m3) - 12
exposure duration (years) - 30 years
fraction of time, wind blows toward receptor (unitless)
= 10%, current; « 100%, future
averaging time (years) « 70 years
unit risk factor (jig/m3)"1 - compound specific
-------
TABLE 4
METALS DETECTED AT ELEVATED
CONCENTRATIONS, BY MEDIA*
Compound Soil
**
Material Piles Tank Sediments
arsenic
barium
beryllium
copper
lead
manganese
mercury
silver
sodium
zinc
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
*X indicates that the substance was present at an elevated concentration
onsite. Only those compounds detected at elevated concentrations were
included in the human health risk assessment
"Including discharge pit sediments.
-------
Table 6 together with their carcinogenic slope factors (CSFs)
for oral or inhalation exposures. Both of these compounds are
considered to be carcinogenic following either ingestion or
inhalation expsoures.
Ecological Assement
In addition to humanjielath evaluations, environmental impacts
of the site were evaluated. No endangered species were
identified on or near the sierra Blanca site. The primary
opportunity for ecological exposures is through contaminated
soils which may be incidentally ingested by animals during
feeding or may be in contact with plant roots. ' High
concentrations of lead at Sierra Blanca, and associated
elevated concentrations of other constituents such as arsenic
and barium, are not dispersed across the site, but rather are
present in distinct and separable locations on-site.
Contaminated materials are found in discharge pit sediments,
material piles, tank sediments, and two well defined small
areas of surface soils.
The remedial action to be conducted at Sierra Blanca will
entail treatment and disposal of the contaminated material in
such a way that the material will no longer be available for
contact by humans or animals. Since the contaminated material
is only located in the above specific areas of the sie, rather
than scattered across the site as is the case at many
Superfund sites, a remedial action directed at those specific
contaminated areas will effectively remove ecological threats
as well as human health risks. Analyses performed based on
available data indicate that using the 500 ppm lead soil
cleanup level ensures no significant ecological threats at the
Sierra Blanca Mill.
Risk Assessment Summary
As stated previously, the risk calculations performed in this
review are conservative. Maxiumum concentrations of
contaminants are used in all but the inhalation exposure
calculations, even though the maximum concentrations do not
occur in the same sample locations. Additional conservatism
is added by the summation of the Hazard Quotients due to the
fact that not all of the COCs may act on the same target organ
or produce the same adverse health effect. Additionally, only
the exposures by hypothetical future on-site resident
population are used in calculating the HQ and carcinogenicity
of each contaminant. This hypothetical population is expected
to endure the highest exposure to site-related contaminants,
and so experience the greatest health risks.
20
-------
Arsenic and beryllium are evaluated for carcinogenicity
following inhalation exposure to surface soil. The summed
lifetime cancer risk is l.OE-06, with individual cancer risk
of l.OE-06 and 2.5E-08 for arsenic and beryllium,
respectively. Generally, a carcinogenic risk value of l.OE-
04 to l.OE-07 is within the range of target risk levels EPA
has identified as acceptable in the NCP.
Calculations of surface soil ingestion exposure show a summed
HI of 3.2E+00 with the highest HQ of 1.4E+00 presented by
barium. As mentioned earlier, only arsenic and beryllium are
evaluated for lifetime cancer risk following ingestion
exposure. Lifetime cancer risk for these constituents
folllowing surface soil ingestion is calculated as 9.3E-04.
Material pile soil ingestion exposure calculations reveal a
summed HI of 4.3E+00, with HQs of l.OE+00 and 2.3E+00 for
barium and manganese, respectively. Evaluation of material
pile soil ingestion predicts a lifetime cancer risk of 7.7E-
05. Calculations regarding ingestion exposure to tank
sediments show individual HQs of 3.01E+00 and 4.4E+00 for
barium and silver, respectively. Tank sediment evaluation
reveal an ingestion lifetime cancer risk of 9.7E-07. Site
ground water has been found not be contaminated with
contaminants of concern.
Using the future scenario, there are no increased systemic
risks via dermal exposure from any COC in any media. None of
the summed His or individual HQs for dermal exposure are above
one. Evaluation of surface soil dermal exposure reveals a
lifetime cancer risk of 6.1E-05. Evaluation of material pile
dermal exposure show arsenic to present a lifetime cancer risk
of 4.7E-06. Tank sediment dermal exposure calculations reveal
a lifetime cancer risk of 5.1E-08 for a single exposure.
It should be noted that lifetime cancer risk calculations for
surface soil ingestion and dermal exposure are performed using
the maximum concentration of arsenic of 731 mg/kg. This
concentration is an order of magnitude higher than the next
highest sample of 79.6 mg/kg or the arithmetic average
concentration of arsenic in surface soil of 50.5 mg/kg.
Cancer risks associated with these lower concentrations would
be nearly one order of magnitude lower. Additionally, it
should be noted that numerous issues relevant to the
evaluation of arsenic carcinogenicity, particularly following
arsenic ingestion, have been reviewed and include
nonlinearities in the dose-response curve for arsenic
carcinogenicity which could reduce the risk posed by a given
dose. In combination with the lower concentrations of arsenic
found at most locations on the site, actual risk or cancer
21
-------
2
3.
S3 S2 £2
tf OS £
i
X
£2
5
CO
3
ac
GO
fe
S
X
cs
8
U*
O
I
„ 8
0£
S £
3 a
|
.
:l 8,
-
u
,0
03
J
5
i 1
iXZ .
•• m
q
co
oi
g.
I
1
I
E
S
'C
S
S s
u
i
re
E
u
S
eo
O
II
•§
-------
o
NO
CQ
<
s
p"
z
^ 05
pg
if
gS
o e
j b
M 5
o 5
s z
2 S
cu S
8g
z z
gs
*"N ^.^
< 9$
3g
z
o
o (*•
Is
»
^M
»)
5
!—•
il
ZJ
o
p
5
t
1
Vl^^
^^
<«•>
I
>_x
1.8E+00
m
o
UJ
«*J
8
+
w
CO
^
CO
o
W
v
-------
could be lower than the values presented in the attached
tables by up to two orders of magnitude. Table 7 summarizes
the His and total cancer risk for each exposure pathway and
media of concern.
VII. DESCRIPTION OF ALTERNATIVES
Numerous remedial alternatives were screened during the
feasibility study process including reprocessing/recycling,
soil washing, thermal treatment, biological treatment, off
site disposal in mine shafts, etc. The screening process
eliminated those alternatives which were not technically
feasible, could not meet State and/or Federal regulations, or
would not be protective of public health and the environment.
Subsequent to this detailed screening process, a total of five
alternatives for the Sierra Blanca site remediation were
analyzed in detail. The following alternatives were evaluated
using the nine selection criteria outlined on page 27 of this
Decision Summary. The details of this evaluation are
contained in Chapters 8, 9, and 10 of the Feasibility Study
report (Attachment 2).
1. No Action
2. Institutional Controls
3. Cement Solidification/stabilization and On-Site Disposal
4. Cement Solidification/stabilization and Off-Site Municipal
Landfill Disposal
5. Off-Site Municipal Landfill and Hazardous Waste Landfill
Disposal
ALTERNATIVE 1 - NO ACTION
The No Action alternative (consisting of monitoring only)
provides a baseline for reviewing other remedial alternatives
for the Sierra Blanca site. Because no remedial activities
would be implemented to mitigate contamination present at the
site under this alternative, it is possible that people could
be exposed to contaminants. With the exception of the removal
of the process chemical drums and tank sediments onsite, no
reduction in risks to human health and the environment would
occur.
Capital costs are $17,000 and as with all alternatives
evaluated, include installing 2 additional ground water
monitoring wells at the site. Annual operation and
maintenance (O & M) costs include semi-annual ground water
sampling and analysis for metals for a period of 30 years.
Present worth of 0 & M costs is estimated to be $48,000.
23
-------
TABLE
SUMMARY O
F RISKS ASSOCIATED WITH POTENTIAL FUTURE EXPOSURE
Index Quotient Compound Risk to Risk
3.2E+00
43E+00
1.4E+00
2.3E+00
4.4E+00
barium
manganese
silver
9.3E-04
7.2E-05
9.7E-07
arsenic
arsenic
arsenic
Future
Scenario
SOILINGESTION
Lifetime - Surface Soil
Lifetime - Material Piles
From Tanks
DERMAL ABSORPTION FROM SOIL
Lifetime-Surface Soil 1.7E-01 7.2E-02 barium &1E-Q5
Lifetime - Material Piles 2.3E-01 1.2E-01 manganese 4.7E-06
From Tanks - 2.3E-01 silver 5.1E-08
arsenic
arsenic
arsenic
DUST INHALATION
Onsite Residence
l.OE-06 arsenic
-------
ALTERNATIVE 2 -
Under this alternative, no active remedial measures to
directly address contamination at the site would be
implemented; rather, legal controls, such as site access and
land use restrictions, would be used to minimize the
likelihood of contact with contamination. Monitoring of
ground water as described for Alternative 1 is included under
Alternative 2 to ensure that the risks to human health are
being addressed. Institutional control measures that could
be implemented consist of fencing, land use restrictions or
deed notices, and zoning ordinances which would limit
activities on the site. These additional measures will also
be selectively included as elements of the other remedial
alternatives.
The use of institutional control measures provide a greater
degree of protection of human health than the No Action
alternative, however, this alternative will not address the
potential for contaminant migration from the site. Also, long
term effectiveness would likely be low due to difficulties in
enforcement.
Additionally, this alternative provides no reduction in the
toxicity, mobility, or volume of contaminants at the site as
suggested by the Superfund law.
Annual *costs associated with this remedial action are
attributed to ground water monitoring costs. Total estimated
present worth cost of this alternative is $93,000.
ALTERNATIVE 3: CEMENT SOLIDIFICATION/STABILIZATION AND ON-
SITE DISPOSAL
EPA's Preferred Alternative
Alternative 3 entails treatment of contaminated waste material
that can leach, followed by onsite disposal of all wastes.
Treatment would be accomplished by a fixation process using
Portland cement to stabilize the waste material. The 225
cubic yards of waste which failed the TCLP tests (and can
leach) are the material piles and the tank sediments,
including cinder block trench sediments. Contaminated
surficial soils and soils within the discharge pits passed the
TCLP tests but remain a health risk due to other potential
exposure routes. This non-leachable fraction will also be
disposed of in the onsite discharge pit.
Implementation of Alternative 3 would consist of leasing a
standard portable concrete mixer and setting it up on the
24
-------
site. Portland cement of a type to be determined based oh
bench scale tests would be purchased and stockpiled on-site,
together with any supplemental sand or aggregate required to
achieve the mix design.
The contaminated material piles would be excavated and
discharged into the cement mixer, where the material would be
mixed with Portland cement, water, and any supplemental sand
or aggregate required. The resulting concrete mixture would
then be transported to the discharge pit and deposited. Non-
leachable contaminated surficial soils and sediments within
the contaminated discharge pits would be excavated and
disposed directly without treatment. An impermeable cover,
the specifications of which will be determined in the design
phase, will be incorporated to restrict the infiltration of
precipitation. The discharge pit would then be covered with
clean soils. Two additional monitoring wells will also be
installed as an extra precautionary measure to ensure
protection of the ground water.
Alternative 3 would be highly protective of human health and
the environment, as the wastes would be treated to prevent
leaching. Additionally, this alternative would achieve
compliance with all State and Federal regulations. A high
degree of long-term effectiveness and permanence would be
achieved since the waste's mobility would be significantly
reduced. Due to the known reliability of the stabilization
treatment method for the contaminated material, it is
anticipated that monitoring can be significantly reduced
compared to Alternative 1 and 2, therefore, monitoring costs
have been reduced accordingly. Alternative 3 is readily
implementable with an estimated present worth cost of $79,000.
ALTERNATIVE 4: CEMENT SOLIDIFICATION/STABILIZATION AND OFF-
SITE MUNICIPAL LANDFILL DISPOSAL
Alternative 4 also involves cement solidification/fixation
treatment of the leachable portion of the Sierra Blanca waste
material, followed by transportation together with excavated
non-leachable wastes to a suitable off-site municipal landfill
for final disposal. This alternative is similar to
Alternative 3, except that final disposal of the wastes would
be in an off-site landfill. Transportation of the wastes
would be accomplished in standard public highway-approved bulk
carrier trucks, of approximately 40,000 Ib. capacity, which
would be covered to control dust.
Alternative 4 would reduce the mobility of the wastes through
treatment. Implementation of this alternative would provide
a reasonable degree of short-term effectiveness, provided
appropriate precautions and control measures such as dust
control are instituted during the remediation phase.
25
-------
As with Alternative 3, Alternative 4 would be highly
protective of human health and the environment since the
wastes would be treated. The estimated present worth cost of
Alternative 4 is $235,000.
ALTERNATIVE 5; OFF-SITE MUNICIPAL AND HAZARDOUS WASTE
LANDFILL DISPOSAL
In lieu of treatment of the leachable portion of the Sierra
Blanca waste material, an alternate approach would be to
dispose of it in an off-site hazardous waste landfill.
Alternative 5, therefore, consists of excavating the leachable
wastes and transporting them without treatment to a suitable
hazardous waste landfill. Because there is no requirement to
dispose of the non-leachable wastes in a hazardous waste
landfill, these wastes would be excavated, kept segregated
from the leachable wastes, and transported to a municipal
landfill for final disposal.
Although Alternative 5 would be protective of human health and
the environment, the degree of protectiveness would be less
than the alternatives involving treatment. Compliance with
State and Federal regulations would be achieved as disposal
of the wastes in permitted municipal and hazardous waste
landfills is allowed under current regulations. Off site
disposal without treatment however, is the least preferred
remedial action under the Superfund Amendments and
Reauthorization Act. The estimated present worth cost of this
alternative is $344,000.
VIII. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
Figure 3 shows the areas of highest lead contamination (in
excess of 500 ppm). Treatment of these soils and waste piles
would effectively address the principal threats due to lead
contamination, potential ingestion/inhalation impacts and
potential migration to ground water. Accordingly, remedial
action alternatives for the site focus on removal of those
areas of soil .contamination and waste piles above 500 ppm
lead, with some continued ground water monitoring to ensure
long-term effectiveness.
Potential remedial action alternative technologies were
evaluated to address soil and waste pile contamination at the
Cimarron Mining Operable Unit 2 (Sierra Blanca) site. This
evaluation was performed by progressing through the series of
analyses which are outlined in the National Contingency Plan,
(NCP), in particular, 40 CFR Section 300, along with various
guidance documents issued by the EPA, Office of Solid Waste
26
-------
and Emergency Response (OSWER). This process addresses the
Superfund Amendments and Reauthorization Act (SARA) Section
121 requirements of selecting a remedial action that is
protective of human health and the environment, that is cost-
effective, that at least meets Federal and State requirements
that are applicable or relevant and appropriate, and that
utilizes permanent solutions and alternative treatment
technologies or resource recovery technologies to the maximum
extent practicable. Additionally, SARA Section 121 and the
guidance documents referenced above require EPA to give
preference to remedies which employ treatment which
permanently and significantly reduces the mobility, toxicity,
or volume of hazardous substance as their principal element.
The details of this evaluation are contained in Chapters 8,9,
10 of the Feasibility Study report (Attachment 2).
Alternate technologies were identified using best engineering
judgement following the guidelines presented in Guidance for
Conducting Remedial Investigations and Feasibility Studies
Under CERCLA (EPA, 1988), Guidance on Remedial Actions for
Contaminated Ground Water at Superfund Sites (EPA, 1988), and
the Handbook for Remedial Action at Waste Disposal Sites
(EPA, 1988).
The initial step in determining the appropriate remedial
action for the Cimarron Mining Operable Unit 2 (Sierra Blanca)
site was to identify suitable remediation technologies. A
review and analysis of the available remediation methods was
conducted and feasible alternatives were developed.
The detailed evaluation process is a structured format,
designed to provide relevant information needed to adequately
compare and evaluate feasible alternatives to allow selection
of an appropriate remedy for the site by EPA through the
Record of Decision (ROD) process. The remedy must meet the
following statutory requirements:
o Be protective of human health and the environment;
o Attain ARARs (or provide ground for invoking a waiver):
o Utilize permanent solutions and alternative treatment
technologies or resource recovery technologies to the
maximum extent practicable; and
o Satisfy the preference for treatment that reduces toxicity,
mobility, or volume as a principal element, or provide an
explanation in the ROD as to why it does not.
Nine evaluation criteria have been developed to address the
statutory requirements listed above and to address additional
technical and policy considerations that have proven to be
important for selecting remedial alternatives. These criteria
are listed and briefly described below:
27
-------
o Overall Protection of Human Health and the Environment -
How well the alternative reduces risks to human health and
the environment, through treatment, engineering or
institutional controls.
o Compliance with ARARs - How well the alternative complies
with all applicable or relevant and appropriate
requirements or, if a waiver is required, how it is
justified.
o Long-Term Effectiveness and Permanence - How well the
alternative maintains long-term effectiveness in protection
of human health and the environment. Alternatives which
afford the highest degree of long-term effectiveness and
permanence are those that leave little or no untreated
waste at the site.
o Reduction of Toxicity, Mobility or Volume through Treatment
Anticipate performance of the specific treatment
technologies that an alternative may employ and their
ability to destroy or irreversibly treat contaminants.
o Short-Term Effectiveness - How well the alternative
protects human health and the environment during
construction and implementation of a remedy.
o Implementability - Whether the alternative is technically
and administratively feasible and whether the required
goods and services are available.
4
o Cost - Analysis of capital and O & M costs of each
alternative to determine cost-effective remedies. Cost
estimates are developed with relative accuracy (-30% to
+50%) and are presented as present worth costs so that
alternatives can be reasonably compared.
o State Acceptance - To be completed for the most part after
the public comment period; this criterion describes the
preferences of the State or support agency.
o Community Acceptance - To be completed for the most part
after the public comment period; this criterion reflects
the preferences of the community.
Below, each of the five alternatives for Cimarron Mining
Operable Unit 2 (Sierra Blanca) soil and waste pile
contamination is individually evaluated and then comparatively
analyzed on the basis of the first seven of the nine criteria
above. The last two criteria above (State and community
acceptance) were fully addressed after the public comment
period, the results of which are stated in the Responsiveness
Summary on page 34 of'this Decision Summary.
28
-------
Alternative 1
Alternative 1, No Action, is implementable; however, it
provides no treatment, engineering, or institutional measures
to control the exposure of receptors to contaminated material.
No reduction in risks to human health and the environment
would occur, therefore this alternative would not be in
compliance with ARARS.
No controls for exposure, other than the existing fence, and
no long-term or short-term site management are included under
Alternative 1. This alternative provides no reduction in the
toxicity, mobility, or volume of the contaminated ores, tank
sediments, and surficial soils on the site. All existing and
potential future risks associated with the site would remain.
With respect to ground water, no effects from site
contaminants have been detected. With respect to soils,
quantifiable risks are present which consist of hazards
arising from potential exposure to lead, with limited
additional effects from other metals.
Alternative 2
The use of institutional control measures, Alternative 2,
provides a greater degree of protection of human health than
the No Action alternative alone, since institutional action
can reduce the potential exposure of receptors. Access and
land use restrictions further limit activities on the property
which would minimize exposure risks. While some degree of
human health protectiveness would be provided by Alternative
2, it would not be protective of the environment since the
contamination will remain.
Like Alternative 1, Alternative 2 would not comply with ARARs
due to requirements imposed by RCRA Subtitles C and D
regarding disposal of mining wastes, and due to New Mexico
solid waste regulations. Although reduction in the potential
for human exposure would be recognized under this alternative,
only limited long-term effectiveness would be provided due to
difficulties in enforcement of the institutional control
measures. Additionally, this alternative provides no
reduction in the toxicity, mobility, or volume of contaminants
at the site.
Alternative 3
Alternative 3, stabilization and on-site disposal, would be
highly protective of human health and the environment, as the
wastes would be treated to the extent practicable.
Additionally, this alternative would achieve compliance with
29
-------
all ARARs. A high degree of long-term effectiveness and
permanence would be achieved. Stabilization is the state-
of-the-art technology for immobilizing metals and has been
utilized effectively for many years. Durability tests are
being conducted on the solidified material as part of the
bench scale treatability tests. This information will be
utilized in determining the necessary optimum mixture ratios
to ensure the long term effectiveness of this option.
^«
Alternative 3 would reduce the toxicity and mobility of the
wastes through treatment; however, the volume of the wastes
would not be reduced as a result of cement solidification
fixation treatment. Implementation of this alternative should
provide a reasonable degree of short-term effectiveness,
provided appropriate precautions and dust control measures are
instituted during the remediation phase. These measures would
be those that minimize or prevent exposure hazards to on-site
workers and adjacent residents during remediation activities.
Implementation of this alternative is possible without undue
technical or administrative difficulty.
Alternative 4
As with Alternative 3, Alternative 4, stabilization and off-
site municipal landfill disposal, would be highly protective
of human health and the environment since the wastes would be
treatedfc and compliance with ARARs would be achieved. The
degree of long-term effectiveness and permanence would be
comparable to on-site landfill disposal, since a municipal
landfill in compliance with current regulations is monitored
closely.
Alternative 4 would reduce the toxicity and mobility of the
wastes through treatment. The volume of wastes would,
however, be substantially increased as a result of treatment,
which would impact transportation costs.
Implementation of this alternative should provide a reasonable
degree of short-term effectiveness, provided appropriate
precautions and dust control measures are instituted during
the remediation phase. These measures would be those that
minimize or prevent exposure hazards to on-site workers and
nearby residents during remediation activities.
Implementation would be dependant on acceptance of the
material by the off-site facility.
30
-------
Alternative 5
Alternative 5 off-site municipal and hazardous waste landfill
disposal, would be moderately protective of human health and
the environment, although the degree of protectiveness would
be less than the alternatives involving treatment. Compliance
with ARARs would be achieved as disposal of the wastes in
permitted municipal and hazardous waste landfills is allowed
under current regulations. A similar degree of long-term
effectiveness and permanence would be provided with this
alternative as compared to on-site landfill disposal.
Although treatment would be provided prior to disposal in an
on-site landfill, the continuous monitoring and active waste
management present in a permitted hazardous waste landfill
should provide a comparable level of protectiveness. The
long-term effectiveness and permanence of off-site hazardous
waste landfill disposal would be less than treatment and
disposal in a municipal landfill, since treatment of the
wastes would be provided prior to disposal in the municipal
landfill. Additionally, the level of waste management and
waste monitoring provided is comparable at both facilities.
Alternative 5 would reduce the mobility of the wastes as a
result of disposal in a hazardous waste landfill. However,
the toxicity and volume of the wastes would not be affected.
Implementation of this alternative should provide a reasonable
degree of short-term effectiveness, provided the appropriate
precautions and dust control measures are instituted during
the remediation phase involving excavation of the contaminated
material.
Implementation of this alternative would be dependent on
acceptance by the off-site facilities. Off site disposal
without treatment however, is the least preferred remedial
action under the Superfund Amendments and Reauthorization Act.
Cost Comparison
1. No Action $48,000
2. Institutional Controls 93,000
3. Cement Solidification/Onsite Disposal 79,000
4. Cement Solidification/Offsite Municipal 235,000
Landfill Disposal
5. Off-site Municipal and Hazardous Waste 344,000
Landfill Disposal
31
-------
IX. SELECTED REMEDY
EPA's selected remedy (Alternative 3) - cement solidification/
stabilization and on site disposal has been reviewed and
concurred with by the New Mexico Environment Department. The
proposed alternative, along with the other detailed
alternatives, was evaluated and ranked according to the nine
selection criteria outlined above. This ensured a
comprehensive and thorough study of"the benefits of each
alternative. This alternative was found to be the most cost-
effective and protective of the alternatives studied.
Alternative 3 - Cement Solidification/stabilization and On-
site Disposal
Also includes:
- removal of process chemical drums and tanks
install two additional monitoring wells, long term
monitoring of the ground water
- deed notice of remediation activities
installation of an impermeable cover/cap for the disposal
area
X.
Final Remediation Goal
Medium
Soils
Chemical
Lead
Point of
Compliance
On Site Surface
Soils
Remediation
Goal
500 ppm
STATUTORY DETERMINATION
Actual or threatened releases of hazardous substances from
this site, if not addressed by implementing the response
action selected in this Record of Decision (ROD), may present
an imminent and substantial endangerment to public health,
welfare, or the environment.
Stabilization of the soil and waste pile material exceeding
500 ppm would provide protection of human health and the
environment by reducing the mobility of the lead in the soils
and its potential for contaminating groundwater. Treatment
will also ensure that the waste is not a significant ingestion
or inhalation risk. Hazard Indices for noncarcinogens at the
site will be less than 1 upon completion of remedial action.
32
-------
Additionally, implementation of the selected remedy will not
pose unacceptable short-term risks or cross-media impacts.
The selected remedy also meets the statutory requirement to
utilize permanent solutions and treatment technologies to the
maximum extent practicable.
The long-term risks associated with the Sierra Blanca soils
and waste piles contamination would be minimized. Short-term
risks could be addressed by ensuring that airborne dusts are
controlled during implementation of the remedy. The selected
remedy could be readily implemented, since no special
technologies would be required; and the remedy utilizes
typical construction techniques.
All Federal and State requirements for this remedy that are
Applicable or Relevant and Appropriate (ARARs) can be met
through adequate design and planning.
Long-term effectiveness is achieved through solidification and
stabilization of the contaminants of concern. In addition,
treatment is utilized to the maximum extent practicable in
this alternative.
This remedy is cost effective in comparison to other
alternatives. The total cost of the selected remedy is
estimated to be $79,000 net present worth dollars (+50% or
-30%). Five-year facility reviews will not be necessary for
the soils since contaminants above health based levels will
not remain. Ground water monitoring will continue for 30
years if sample analysis deems it necessary.
The selected remedy provides the best balance of tradeoffs
among the selection criteria used to evaluate the five
proposed alternatives for the site, as discussed in this
Record of Decision.
Community and state acceptance is favorable to this remedy in
comparison to other alternatives presented during the public
comment period.
XI. DOCUMENTATION OF NO SIGNIFICANT CHANGES
The Proposed Plan for the Cimarron Mining Operable Unit 2
(Sierra Blanca) site was released for puubliccomment in June
1990. The Proposed Plan identified Alternative 3,
solidification/stabilization and onsite disposal, as the
preferred alternative. EPA reviewed all comments submitted
during the public comment period. Upon review of these
comments, it was determined that no significant changes to the
remedy, as it was originally identified in the Proposed Plan,
were necessary.
33
-------
XII. RESPONSIVENESS SUMMARY
Community Preferences
Based upon the responses received during the public meeting,
it appears that the Citizens of Carrizozo, and town officials
have preference for the selected remedy of solidification/
stabilization and onsite disposal. Only one citizen commented
at the public meeting regarding the potential for off site
disposal and no comments were received from town officials.
No additional comments were received during the 30 day public
comment period, which ended on July 10, 1991. The New Mexico
Environment Department has provided formal concurrence with
the proposed remedy.
Integration of Comments
1. Comment: Could soils available on site be used as a
neutralizing agent and mixed with the lead contaminated
materials to reduce the leaching potential?
Response: No. Athough the soils onsite do provide some
neutralizing capacity, the quantity of soil necessary to
render the contaminated material non hazardous would be
much greater than the cement required for the proposed
solidification remedy. Due to the resulting increase in
quantity of material to be handled and increased monitoring
requirements, soil neutralization would not be as cost
effective nor as protective as the proposed stabilization
remedy.
2. Comment: Are two additional ground water monitoring wells
" necessary?
Response: Yes. Based on the studies conducted at the
site, EPA and NMED concluded that two additional ground
water monitoring wells and continued monitoring are
necessary to ensure protection of the local ground water
resources.
3. Comment: Is the solidification/stabilization of lead
contaminated soils an EPA accepted process?
Response: Yes. The solidification/stabilization of metals
contaminated soils is the state-of-the-art technology for
immobilizing such contaminants. The technology is
successful for treating contaminated soils with much higher
lead concentrations than those found at "Sierra Blanca".
Treatability studies were conducted during the Feasibility
Study to determine optimum cement/soil mixture ratios and
leaching tests indicated the process is highly effective.
34
-------
4. Comment: Why is solidification/stabilization and offsite
disposal not considered a better remedy?
Response: Superfund law requires remedies to be cost
effective and also directs EPA to give preference to on
site remedies. Disposal off site would be approximately
three times the cost due to the extremely high
transportation costs and disposal fees, with no increase
in protectiveness, over on site disposal.
5. Comment: Is the proposed clean-up level of 500 parts per
million lead safe for the residents of Carrizozo?
Response: Yes. This clean up standard presumes that after
remediation the site will be lived upon by families with
children (who are most sensitive to chronic lead
poisoning). It is EPA's best current scientific judgement
that resulting soil lead levels less than 500 ppm are safe
for human beings.
EPA utilized a computer model, referred to as the Uptake
Biokinetic Model, for helping to verify or refine cleanup
goals. This model was used taking into consideration all
potential sources (air, soil, water, etc.) of lead exposure
with regards to site specific aspects of the Sierra Blanca
mill and the Carrizozo area, for generating a safe cleanup
level. The results of this modeling indicate that a 500
ppm lead cleanup level is safe and appropriate.
6. Comment: In a layman's perspective, how many car batteries
would it take to cause the level of lead contamination
found at "Sierra Blanca"?
Response: The lead at this site did not originate from
batteries. A logical comparison can not be made between
the lead in car batteries and the minute particles of lead
found in the approximately 570 cubic yards of contaminated
soils and tank sediments at the Sierra Blanca site.
The severity of lead contamination is based on a potential
for inhalation and ingestion of lead, with 500 parts per
million lead being the health based cleanup criteria. Lead
concentrations at Sierra Blanca range as high as 46,400
parts per million, or more simply stated, approximately 100
times the acceptable health based limit.
35
-------
Attachment 1
Integrated Uptake/Biokenetic Modeling
Since there are no USEPA-approved RfD values for lead, it is not
possible to evaluate the noncancer risks of lead by calculation of
an hazard index. An alternative approach is to estimate the likely
effect of lead exposure on the concentration of lead in the blood
(PbB). Several mathematical models have been developed for
calculating the value of PbB as a function of environmental
concentrations of lead. Of these, the EPA's Integrated
Uptake/Biokinetic (IUBK) «odel called LEAD4 has the greatest
flexibility and has been most thoroughly validated, so it was
selected for use here.
LEAO4 is a lead uptake biokinetic model which could be used as an
alternative to calculating Hazard Quotient for lead. LEAD4
estimates the likely effect of lead exposure based on the
concentration of lead in the blood of children between the ages of
0-84 months. The model was used to evaluate the effect of surface
soil ingestion on blood lead levels in children ages 0-84 months
for the Sierra Blanca site assuming a residential scenario. The
model LEAD4 is limited to children and can't be used for adults due
to large biological differences.
It is commonly agreed that young children are more susceptible to
the effects of lead than older children or adults. This is based
on three facts: 1) young children tend to have higher exposure
levels (especially to soil), 2) young children have higher lead
absorption rates, and 3) the nervous system of infants and young
children is more sensitive to the neurological effects of lead.
It shoi&d be rioted that some parameters of the model cannot be
adjusted to approximate adult exposure, i.e., ingestion rate,
other parameters including specific body compartments could not be
adjusted to the adult representative sizes. Therefore, the risk
to adults from exposure to lead could not be calculated using the
model. However, we might cautiously assume that concentrations
protective to children (sensitive population), might be protective
to adults.
The model was applied on data from the site and Carrizozo the area.
The percentage of the child population that would exceed the
critical cutoff point of 10 ug/dL blood level was 21.38 based on
average lead concentrations on site (Figure 1). The percentage
could increase to 99.99 if the lead exposure concentration is based
on the highest lead concentrations in onsite materials (Figure 2).
A value of less than or equal to 5% is generally considered
acceptable. That is 5% of the population will have a chance of
exceeding the cutoff blood lead concentration of 10 ug/dL. For the
Sierra Blanca site, a soil concentration of 500 mg/kg will achieve
less than the 5% value (see Figure 3).
-------
EPA believes that actual or threatened releases of hazardous
substances from this site, if not addressed by implementing the
response action selected in this ROD, may present an imminent and
substantial endangerment to public health, welfare, or, the
environment.
Figure 1
Input Value: Soil/Dust Lead Concentration = 1470 ppm
Cutorr: IB.a
x Abov*: ai.a*
X Bolow: 71.CX
G. Moan: 7.74
c
«i
II
la is
BLOOD LEAD CONCENTRATION
8 to 84 Month*
aa
-------
Figure 2
Input Value: Soil/Dust Lead Concentration = 18,900 ppm
Cutoff: la.a
X Abovo: 99.9*
x B«iew: a.ei
C. Mean: 40.48
•
I
3
48 68 88
BLOOD LEAD CONCENTRATION
8 to 84 Month*
148
168
-------
Figure 3
Input Value: Soil/Dust Lead Concentration = 500 ppm
• t
e e
- e
2!
Cutoff: 18.0
x Above: 0.33
X B*low: 99.49
C. Mean: 4.14
4 * • 10 12
BLOOD LEAD CONCENTRATION
0 to 84 Months
14
1C
-------
Attachment 2
IDENTIFICATION AND EVALUATION OF REMEDIAL ACTION REQUIREMENTS
8.1 INTRODUCTION
In this Section and the following two Sections, potential remedial
action alternatives are evaluated to address the contamination at the
Sierra Blanca site. This evaluation is performed primarily by
progressing through the series of analyses which are outlined in the
National Contingency Plan (NCP), in particular, 40 CFR Section 300,
the Interim Guidance on Superfund Selection of Remedy, December 24,
1986, Office of Solid Waste and Emergency Response (OSWER) Directive
No. 9355.0-19, and the Additional Interim Guidance for FY 1987 Records
of Decision, July 24, 1987 (OSWER Directive No. 9355.0-21). This
process, in part, enables EPA to address the Superfund Amendments and
Reauthorization Act (SARA) Section 121 requirements of selecting a
remedial action that 1) is protective of human health and the
environment, 2) meets Federal and State requirements that are
applicable or relevant and appropriate, 3) utilizes permanent
solutions and alternative treatment technologies or resource recovery
technologies to the maximum extent practicable, and 4) is cost
effective. Additionally, SARA Section 121 and the guidance documents
referenced above require EPA to give preference to remedies which
employ treatment which permanently and significantly reduces the
mobility, toxicity, or volume of hazardous substances as their
principal element.
Section 121 (b) (1) of SARA requires that an assessment be conducted of
permanent solutions and alternative treatment technologies or resource
recovery technologies that, in whole or in part, will result in a
permanent and significant decrease in the toxicity, nobility, or
volume of the hazardous substances, pollutants, or contaminants. SARA
requires that the following treatment alternatives be developed:
"Treatment alternatives should be developed ranging from an
alternative that, to the degree possible, would eliminate the
8-1
-------
need for long-term management (including monitoring) at the site
to alternatives involving treatment that would reduce toxicity,
mobility, or volume as their principal element. Although
alternatives may involve different technologies (which will most
often address toxicity and mobility) for different types of
waste, they will vary mainly in the degree to which they rely on
long-term management of treatment residuals or low-concentrated
wastes. In addition to the range of treatment alternatives, a
containment option involving little or no treatment and a no
action alternative should also be developed"
Remedial alternatives are identified using the guidelines presented
in Guidance for Conducting Remedial Investigations and Feasibility
Studies Under CERCLA (U.S. EPA, 1988), Guidance on Remedial Actions
for Contaminated Groundwater at Superfund Sites (U.S. EPA, 1988) and
the Handbook for Remedial Action at Waste Disposal Sites (U.S. EPA,
1988) .
Analysis of remedial alternatives is based on an evaluation of the
following for each alternative:
Degree to which alternative is protective of public health
and the environment.
Degree to which alternative meetr. applicable or relevant
and appropriate requirements (ARARs).
Technical feasibility.
Cost/benefit analysis.
Identification and screening of remedial alternatives for the Sierra
Blanca site were performed using the following steps:
Development of Remedial Action Objectives (based on ARARs,
risk assessment, etc.)
8-2
-------
Development of General Response Actions
Identification of Volumes and Areas of Contaminated Media
Identification and Screening of Remedial Technologies
Evaluation of Process Options as to Effectiveness,
Implementability and Relative Cost
Assembly of Alternatives for Remediation
^
These steps are detailed in subsequent sections.
8.2 CONTAMINANTS OF CONCERN AND RISK BASED EXPOSURE CRITERIA
As discussed in Sections 4 and 7, groundwater at Sierra Blanca has not
been impacted by site contaminants and is, therefore, not addressed
in the FS.
The contaminant of concern in soils, discharge pit and tank sediments,
and material piles at Sierra Blanca is lead. As discussed in Section
4 and 7, arsenic and other metals besides lead are found at elevated
concentrations at the site. However, as discussed in Section 6,
arsenic^ and the other metals present much less risk to human health
than the risks posed by levels of lead found in the same materials at
the site. A concentration of lead in soil exceeding 500-1000 ppm has
been established as a cleanup criteria by EPA's Office of Emergency
and Remedial Response and Office of Waste Program Enforcement, Interim
Guidance on Establishing Soil Lead Cleanup Levels at Superfund Sites
(OSWER Directive #93355.4-02, EPA, 1989). As discussed in Sections
4 and 7, lead levels far in excess of 500 ppm are present in various
waste materials at the site. Only those areas of the site where lead
levels are high are arsenic and other metals concentrations also
elevated. By approaching the site remediation in a manner to address
those areas where lead is found at concentrations above 500 ppm,
elevated concentrations of arsenic and other metals will also be
addressed.
8-3
-------
8.3 ARAR-BASED EXPOSURE CRITERIA
Under Section 121(d)(1) of the Comprehensive Environmental Response,
Compensation and Liability Act (CERCLA) as amended in 1986 by the
Superfund Amendment and Reauthorization Act (SARA), remedial actions
must attain a degree of cleanup which assures protection of human
health and the environment. Additionally, CERCLA remedial actions
that leave any hazardous substance, pollutant, or contaminant on-site
must meet, upon completion of the remedial action, a level or standard
of control that at least attains standards, requirements, limitations,
or criteria that are "applicable" or "relevant and appropriate" under
the circumstances of the release. These requirements, known as
"ARARs", may be waived in certain instances (see Section 121(d)(4) of
CERCLA).
ARARs are derived from both Federal and State laws. Under Section
121(d)(2) of SARA, the Federal ARARs for a site could include
requirements under any of the Federal environmental laws (e.g., the
Solid Waste Disposal Act, the Clean Air Act, the Clean Water Act, and
the Safe Drinking Water Act). State ARARs include promulgated
requirements under the State environmental or facility siting laws
that are more stringent than Federal ARARs and have been identified
to EPA by the State in a timely manner. Subparagraph 121(d)(2)(c) of
CERCLA limits the applicability of State requirements or siting laws
which could effectively recult in the statewide prohibition of land
disposal of hazardous substances, pollutants, or contaminants unless
certain conditions are met.
Subsection 121(d) of CERCLA requires that Federal and State
substantive requirements which qualify as ARARs be complied with by
remedies (in the absence of a waiver). State requirements can be
waived if a State has neither consistently applied nor demonstrated
the intent to consistently apply a requirement in similar
circumstances at other remedial actions within the State (Subparagraph
121(d)(4)(E) of SARA). Federal, State or local permits do not need
8-4
-------
to be obtained for removal nor for remedial actions implemented on
site (Subsection 121(e) of CERCLA), although substantive technical
requirements will be attained.
The definitions of "applicable" or "relevant and appropriate"
requirements as derived from the NCP are as follows.
Applicable requirements means those 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 or contaminant,
remedial action, location, or other circumstance at a CERCLA site.
For example, at a site with contaminated groundwater, Federal drinking
water and State groundwater standards would be "applicable" if
contaminated groundwater was being directly used as a drinking water
source.
Relevant and appropriate requirements means cleanup standards,
standards of control and other substantive environmental protection
requirements, criteria or limitations promulgated under Federal or
State law that, while not "applicable" to a hazardous substance,
pollutant, contaminant, remedial action, location, or other
circumstance at a CERCLA site, address problems or situations
sufficiently similar to those encountered at a CERCLA site that their
use is well suited to the particular site. For example, at a site
with contaminated groundwater, Federal drinking water and State
groundwater standards would be "relevant and appropriate" if the
contaminated groundwater was not currently being used, but was a
viable potential source of drinking water. Requirements may be
relevant and appropriate if they would be "applicable" except for
jurisdictional restrictions associated with the requirement.
The determination of which requirements are "relevant and appropriate"
is somewhat flexible. EPA and the State may look to the type of
remedial actions contemplated, the hazardous substances present, the
8-5
-------
waste characteristics, the physical characteristics of the site, and
other appropriate factors. It is possible for only part of a
requirement to be considered relevant and appropriate. Additionally,
only substantive requirements need to be followed. See 40 CFR Part
300, March 8, 1990.
There are three types of ARARs. The first type includes "contaminant-
specific" requirements. These ARARs set limits on concentrations of
specific hazardous substances, pollutants, and contaminants in the
environment. Examples of this type of ARAR are ambient water quality
criteria and drinking water standards. A second type of ARAR includes
location-specific requirements which set restrictions on certain types
of activities based on site characteristics. These include
restrictions on activities in wetlands, floodplains, and at historic
sites. The third type of ARAR includes action-specific requirements.
These are technology-based restrictions which are triggered by the
type tff action under consideration. Examples of action-specific ARARs
are Resource Conservation and Recovery Act (RCRA) regulations for
waste treatment, storage and disposal.
ARARs must be identified on a site-specific basis considering
information about specific chemicals at the site, specific features
of the site location, and actions that are being evaluated as
remedies. If no ARAR covers a particular situation, or if an ARAR is
not sufficient to protect public health or the environment, then non-
promulgated standards, criteria, guidance, and advisories may be used
to provide a protective remedy.
Tables 8-1 and 8-2 contain a listing of ARARs which have been
evaluated for Sierra Blanca. These tables identify each potential
ARAR and whether or not it is "applicable" or "relevant and
appropriate". The remainder of this analysis describes and evaluates
the three types of ARARs in greater detail.
8-6
-------
1
ft
1
< g
£<
4 w
O g M
I » fc -
3 P!
1
Cj S
3s
M B
•Jl
i
u
u.
1
•3 c
c 5
•w £
(A V)
** 10
S3
si
a"
m
e
s
TJ
X C «
3 ".3
S g &
H > O
— ( • U
e
o
Dascripti
§
•H
2 5 >
O TJ -H O T) -H
• UO4J flLt«4J
J5 « U U J5 « iJ U
4J a a w a «
§ j-> « 3 w «
•WOC-4 4JOG-4
ObOV ObO«
z CP u "i z cr u k.
0 0
§. i
u w •
• 1 TJ « 3
• a • «i « -H
m S « u 3 X
5 u C •? o 8
1 "4 O • -H —
£ -1 U u ^ £, M
OK — O U
tntiMm ioi« W4J>*O
Uiane U»MU
(T -H -H
o
O 4J U
«. £ 2
U PS B
S b b
fN O O
tr
w c
E .1 \
U •* -1
B b c b
E C S Q
W < b
0 L7
H ^ 5 TJ C TJ
H 2 • w 0-4
B 8 £ 1 wl
• M * 4
14J AJ «U 4J
g 25 15
. ' '
1
•y
P tJ J N, \
O> O^ \ 5* • ft
B m in
O O f*t *H O O
o o «-< o o o
1 1 1 1 1 1
4fiser«
4J -H -H
2 S 5 u
3 * ° *"
* C B • - *
• • t5 -3 b O JJ
X4J4J* •Tj4JbT9
4JO-HIO •rtgCO'b
e Hi • e i S «
• -rt -^ • JfO
MM>*JJ bO6C
a£ > cn*«4T)4J
U TJ -H 3«MUM
• b • 4J O AM
£ t u u b TJ r o> c
u « « ir*io
iwia § -H • « *J
4JOCM >9D^O
ObO« oenib
zo 4J
5« s • c e
-i a » -H o 4J O O b 4J
C «J -H • « o «
•H 4J w m • •
je 4J e u -u u
B « « • • Ob
•H in *) b 3
b b £ • a O b
TJ 10 O 4J 3. n •
•H ^ 61 b 4J
»«B«j O TJ •
58.SJ81 ^S*
« C os o tr
-H >,.* • C J u C
>^4J m 3 >i -a tr-H
^} -*4 O U 4J -»4 U J<
« ^H c * j: « > • c
. «)
O 9
I ^
ot v n
V -p
• u
2 *J 2
«l f>
js es
p o o v
"3
3 §
JJ -H 0)
C 4J C
s ,s.s
• c «
IQ MM
3Bi*0
« b u
1 1
-------
M
a
g3
M 5
< u
I zle
« H fc *
H u cc 5
ai
si
a5 •
u:
b,
1?
S ;
JJ J
W 0
jj n
C 4.
||
a.
4.
•o
x c e
e 4 4J
-4 4
Sc'Z
u 4 a
H > O
~l 0 b
1st
jj
Descript
§
-H
JJ
4J
•H
O
n
- B
c 2
e jj
• «
e jj
b -H
•4 •
3 H
S
CK b
O
•o •
b •
•1 **4
V b
e e
VI b
U
2 in
O JJ JJ -H
jj « H «
60 H
•nee fl
« jj u £ e
b C 1-H JJ
§ g S -3 * I .
D< JJ 3 U 3 JJ
TJ b « 6" H -1 «
e o £ .- o -4
« JJ n b £ B 3
JO -4 C -4 ^ -.4 O
•H « £ « Si — -4
jj e in jj
>. « £ Hjjjjeb
OJJ3. -1 C U K «
••4 &• c £ • • « a -~
U1-444J 4-HJJIW *O
JJ«I • JJ£O^b«
• 3 o 3 inlbeoe
w 61 jj £ u « a 1 u-i ~i
SO IN
P- •*
1 -4 -H 1
-4mb ^ o
in -4 e o m
-4 *i -H r- jj
b b b
VI « U b VI 4
vi a> e vi a,
Is 6l* s 6
M O3O IN O
«
e c 3
•H jj n
b >, C T3
U b C b
2 H H b Z 4
-4 U Ol JJ
II * -fr«
S b 2 O B -H
e -H o -<
1 i § in
D i D i
n
Is
u
S3
« jj
»|
S »
0 *
•H b
V) «
n
•S5 .
•S3
U JJ -H
•H 3 n
sl!
1
§
b 1
0 3
"" 3 - 0
«J 2 h'S
•C O* b C
b 3 nj
•i in o O1
•g 3 b b
S6 e o
•Sic
jj b -H
Sets emission
designated haz
tants includin
berylliuB, and
arsenic
-•
b
Q.
6
o
i-
flS
|3
* -H
JJ — 1
<"£
o|
n
in in
•H 3
-1 •
• M
0 5
••4
JJ b
1
\
l\
U b
'o •
3.
e o
£ «
S i
u
8. •
n -4
Se e
-4 4J
•*4
S B" "
Sfl B
B 0
|
i!
W ~4
•H TJ
&So
e £ jj
b
« M
^H o e n
0 *> 0 B
b M -H O
Specifies cont
•ents for asbe
and work pract
control ••issi
3
*S
U •-(
Q. *
06 *a
O 1
O
o <*
32
b B
« -1
JJ -4
in o
in
S3
m
in n
•H 3
2£
-4 •
« H
§2
S£
i
e
11-3.2
'b b
1 l|
e > •
4J b
•H e e
ns
§| ;
2 < 3
3S3
~ Pi -H
•H d
O JC
ili
M
M TJ
ft is
•H -H M
° Is
JJ b i
i :§
AMnded Solid
Act
Specific closu
•ents for i»po
landfills
p- «
at o o
T in *3 S
-4 ve u •
e
-------
§
M
|
it
0-
la
°le
I « e -
2 ^ii
i§s
APPLICABLE
)ERAL STANDARDS, R
u
h.
|
Ul VI
*i «
C -u
is
I
0
«-t 9 ki
III
Description
4J
3
M
• *J
f u
o
•D -
S 2
4> ••<
M W
, „,
1 in •§ -S
«• e 3 e
E b .* -H
f 0 U •
A x u
IM e iu e
O O>-H S -I «
•H C *> D « >
u -H c te m o
uwe o Z
a a b b a
b e b « in b
•u u 3 *a H e
X O O C TJ 4J
e b 3 - u o
M *J H b e OH
4J •* E • *"
tn O TJ O 3 01 -
S-H e b o * »
M e
tJ H in 3
B U *> O
• *j tea
Is S-iI
' \c *
I in
0 IN
1C V
VI « O
VI S "
u p t!
•N 0 3
^
m
i 5
U < in
H 3
C Z 0
P O T)
J M b
1 H «i
K < N
W > «J
8 1 £
° le °
SO < e
u» 2
!O 6 'S
w 0 o
:s •
T>^,
• C *O
(A B S b
§ o « 'S a S § 5
O b oeui*HOO
B> B "O -rt O>
emin •-<*>. ne^
| t
£
in -u
in -H -H •
O C 6
- 3 o -a v
•u o u e B
a b 3 «
-1 ,
&> « -H cr 4J
• T) JC b •
b B M b e «M
3 x g T3 «
u c S B en
• o « 3 «
j; jj 4^ n e b
u e B f e
•H ^ e 4J -H 3 J(
~i e o> « nb
.a 4J « ^i' u in o
» • b 3 c « S
4J -H O 6* O
in e 4J e -H o «
M! w
HI ^
ao 3
3 *> B
VI « OH
i ea
. 8-
SH U
*» -H « •
^«i
•H b
b « n T3 3
O C *J n
- .2 § S u
?ti!c°
b • b O b
•H -H -H e
p_ « ? 4J JJ
v. « S1 « a
e e e ^i i
b O b •O *O *
4.S-.191.
o e > e o e
C b H b b E
*j o> 3
M < B O -H
•- J S c • a
0 *J v
4j SL m - -H m
• 0 % e " "
C n > c u*
e e • o e
Out e S -w
, -rt H 0 *J •
< « u s o a
|
n
o e
4J U
5«.55
jj 4J n
B e
b fl O TS
o w b e
** 3 3 4J
-4 O -H
u — « n e
4J O D
•s8-^ .
k* . 0
e b c
* a a n
•H £ b
3 U • «
& M O JJ
IN
fN
•H
in
4J
b
•
S
g
tn
o «N
V -H
&
b
•5
•8
a
•*4
Q
4J •
c e
• 4J
4* a
3 >.
B '3"
*J
1 IS
S O -H
*H •
Z ** -H
2 • *H
U Z U
. '
-------
P»
"4-1
O
8.
«
cu
1
a 3
M §
* <
g <
*• g
0 g M
I OH -
1 lai
F M
si
&
j
1
[L.
It.
*?
c !
* <
tf) V
4J in
s.t
* ~"
tt
V
c
u
T3
x B e
« * JJ
•H «
1 B n
u « a
H > O
L.2 0,
g
H
a
•H
U
in
°
g
•H
^
U
n
jg
E ••<
e *>
krf -*4
•4 •
Q
•o -
b •
' 2 .tJ
w u
*
B •
•H Ul
B B
SO
•H
f 1
0 D>
B
O -H
s 1
!i
x
g
•H
b Ul
3«!tr
S§T,§.
^ ss
>; « «
b> ^1 o< u
0 H B
-i H -i »
0 •" 6 U
E "* -H ^
!.s §
• c • w
J*> « U
« A .1
.3 O **
s'SIs
o
u
cu
PJ
c
o
in
§
u
*a
4J
1
u
1
c
(Jl
in
• H
TJ
O
u T3
E 01
v a
•H
a
ul
o o
Z 4J
t
§
- £ E
S tJ S3
4J 3 E « E
E in •- B 0
o m « 4J u
u a u in 10 •
a « « c >. o>
o n-i u> i- 5 TJ
*J X h" Kl 4J E 3
U « « -H
m •< *> o TJ £ «
•a £ E o a u
u 3 .H u e •« «
fui K O 3 *
*J 0 V J
*j « £ a »H o in
«1 4J D» B U
M -H O fi -H JC *J
4J ~4 U 9 ^ U a
e o £ u 3 0 E
V) Oi *> *J Ch 3 -^
o\
fN
rN
O »<
«r o
4J IN
ia IM
a vi
B U
U. Ul
U 3
o m
B
j
4J O
E P
i i
u
tn
u
M (4
i kJ O
*u VI
i S y
v) x
g
*
4J
•H
n
1
e
o
•o
•M .
•H
JJ
1
•H
U
j
|
g
u
E
a n
4J
shes storage
1 requlremen
•H •
>^ VI
JQ Q
ID QI in
l~
V
h
fi
Q.
Pi
U
O
in
I
kd
H
9*
1
m
e *
• M
a ll
-*4 -H «]
c • •
O kJ i-i Q«
• fn o •
n • 4J £
a M "o, ,»
e P: * S
n U U M
O -H
9v n 4J
•H -H
•H b J= >
g 45 5S
£ 5*8 !.
in
Z S
in
*J ^ £
C ^ 4J
i g -2
5s s
H 1
ki ki U
1
« o
£ 4J «
u in e
•H TJ IT iJ
-< e B « >.
55^ 12
in v « • «
u u *j a M
p^
Ot
•H kl
u
U 0
w •
selected
nvolves t
materials
•H «
^ 5
Will app]
alternati
of hazarc
^
e
X
o
g
•H
*J
es transport
us materials
^
7 *
ll
r-
o
u
a
a.
KP
S £
£§
M M
P 1
•C O
is
2 b
S C
15 S
C5 <
Q P
-------
r-
e
JJ O
B H
* JJ
b -H
•H I
*s
b «
e •
JJ •«
-i « b
* M b •
• b u 3 £
b O H U 4J
3 14 b « O
JJ O 2
U « JJ b
>S~I m >• 0
"•ss. - • a
*J H 4J 4J «
i * ' £ I S
!b -rf b • S . W Bl
^H « 4J — < •
O3OV1 0*3 O b-H
C JO ^ B B 3 »
•o o< -i *" J.
«-«« «« « « C
ccuo: • u • BO
O 4J Ul O -H O
t).^.H-< iitr "O o«
01 -1 * o B •
?C £1-1 >. 21
»JJQ ^O *t5l *^
4JU*»4 «• VJ£ bO
U«4J •£ tb • Z
V H 'r~i 14 9 u • IB
bb^)Z bb bl • b
4J O « "8 b •
« in « « • C •*>
P-OOJJ Po PJ P»
S § § S
• 1
-i ' S -* rf >, u
4JU 6E--, « >, jj £ « >5 O JJ
V O-«J O 0) OUOb jj *OjJbb BB>ifl O
H«4JCH£»C-1 00«JJ«bH ••< O « • b ^ « b TJ rt
u m -i 3 JJ -i o o. m -i -< « bojj u « Z -c « « jj c u ^
BC-Hinja J5 -H CJJOTJiHC u CUM BJ C b • M 3 O "D
• £ in C JJ -1 4J U b«tl OT34JKI « C J< *< 3 fl OON IU-H
erjjin«-U(rigrf 3 > £ « « u tr«bO e -H -H >, >, -H
«J « U • « H 2 b T3t.Uj2CU.ai-D « JJ 5 T3 3 JJ V u c T! C S
JJ 1 --I JJ -0 -< o C«b O '" « Ul J f>, -H -< « C O S O O
« 3 -^ mo £ m o« £ JJ bE « x c W > £ ^|4J
Ub JJ 0 c « B « C H T) • Q<0« C « C JJ 0 £
• •CPU c-!w nb jj jj o -i « £ tj • jj o a b o 5 b «
• elans'* -S« -H«H££«3^D. ••o'qbn S-iS"«i*ib'o'!jS' "onJJb'e* &CUJJCQi W^O-O »O«
• o 3
s §
8 u i
B O* OH
u o * Q
1 « 38
(J P CD H
C 2 u" § 1
1 i ^§ is i
"2 § ^ M ^ §
8 § ii ii
| is si si Is
-------
r-
*j
o
\c
s.
«
CU
«
M
S o
0.
Cu M
% K
< U
<" „ p
o e HI
2 a!8.
M 5 5 fc
uJ 0; 3
a o a
u S
M OJ
& 3
• s
u
u.
i
•3 ?
c 5
4J «
B 4.
II
n
1
u
T)
-4 4
ja u --i
9 E n
H > 0
i e u
*«*
e
o
•H
a
•H
14
U
m
§
•H
•H
U
tn
Jg
i«
• V
•H B
tH
U
0
U «
w u
•o
B in 4J
3 T) u B
o >. • « e
«M £ ' O* 4J .X • O
e TJ « M i in a
e TJ u « S p • -H T> "O- '"
we-* u SinnB • S ^
S4J > -a e u c 3 el •
u u -4 u e o x >*^.
e 3 e m .0 o « u jj I S "
-H >,-6 M on a e OE o
u B •**• •
O. 3 u *j tr>o ue-rf« "
WO-H ki4-H 3^e "O -H
U^'H -i o o -H 3 IU 4J-H
0»U» T)-H| in e c « -£TJ «
BET) • BO * u e
5 H « c O-4U o -H T3 O u
T3 J « C « C CP *J -I 4>O «
• 0 H j; » ^ £ CH « 0 C « «
4JI0^«4J J34J$ H
ee-H 4J U-H « - e
£U4JU. -1 « «J -1 « «4J -" C B
4J 3 - -ISO -1 HJ -rt « ••< C
on> -*4 -HIUT)JS etf e*
UBUI a-H4J t a «4J « -^ T) e
O90< rHkJ 0 >*4Q| «H4J
tr>£3 e-H« « u, S-o "tT -HH
8 3 " , S*40- SOW1£ .g *"
IS§5 pSS g.5i« g£ SS
O O O o Q jQ
« *O a
e « w •
£ o-H*Jmcoy£
• u i *J .a « in c -H w • c w B
> H i jj .H .H o o n
uB£T3 i ^ uu n « u -H H « nuoe«e
m£ i -H .rf » uiu H o in u -< u -H -i j< « U a S >
C4JCfl( ^jti-i^ 4Ji -H
3 o o cr u t, u treino in u • tp w >, o « 13 -H -i
oin in « C 1-1 -i o
4Je«« *O> IU4J 4JU4J4JO4J eB««-H «4J
•H4J«4 mea fi«*-4xiaou«n*4*J ^u
§o « u 4JD, o •) t) e «
B4JC - TJ '- b S U C 3 >M X U 5. e 4J 4J C *> 'S « _
•HcuHa B«O « jt • « » - « « » -i » e £ u « o e w TI
4J Ul XI «1 UU4J I- k. -. -6 £ M B -O C 4J C « k. « •
u 4 eTJB «o^ e^vem MC ejs-HdijJv 4J
« -0 £ -n a - a » « b.«'€T3 bSmafuB unu
ei u o> okiBOB-H c-4H«««m«
• • « • e * «o> e > £ -< w -i « ewHTTe-HQi « c •
utrucr kte-Hin u * hih>04J4/>i4J6 h«4JO«T)o -HU-H
-i c — i c .H O' u u -J-H>w36S »>iM'MT>-5e ^'gw
o
i —
O 0 •
OO o
UOSPiUB* UK OCCQi 0 UP«
DUO DU 3U UONU Off* DU
«oo '•toi-i ^m x^oe MX «o
vHinin m^r\* /^»n uxvff CI]»H «Hin
in » Z z
w oo O H
E -1 M <
« tt J
E b. U CU
ecu o
s I 5 „ £ S
(0 ' OS y 2 ? Z
U cc R O O
^ t -•-; | ^ S B f.
" < t? = ° i. I *
Q |°o IB el ute M
S i ti i i « i] §
° ? ' T ' ?fe . ?
-------
cab
levant
propti
App
s sa
•3 e
si
V) V)
Re
Ap
^.
M U
u
s
It
•H
3
s:
•o u
« •
8,
u «
c2
-a -
ID « E
•H « b
4J *J O*
" * 2
•H V) Q,
sli
as up!
b §b
-------
TE
LIMITATIONS
1
!<•
II
S«
> t
si *
g|
3a
Si
i
w
s
3
Standar
hown)
4J OT
M
5-
4J
U
T>
> B b
III
g
•H
a
•H
U
U
m
2
§
-U
•H
U
n
*:§
B -H
!s
.5 -a
0
•o -
3
E •
4 4J
*> -H
V) b
U
•~J
'on • n
b • >, 3 b
§S-£.
u -6 « • 3
>1 • §• • •
4J £ 4J U
H jj b a a
~H • -4 "W
« n v 3_ b
b J3
b JS 4J 3
• U • O «
4J -H « 4J
C •• «
£ B n «
4J O b m u
H • -3 «
tn in 5 b ib
• M O * b
4J -H fii-O 3
« • B 01
• 1 T3 «
b 0 B U O
u U « in .u
e
•H 0
£ U
4J -H
* I
U »
3 B
n o
•§1
M
o*
ll
U b
"b
r w
V) O
•
•u •
3 ~t
•u U
• -H
o^
u -
M r*
2 .
*H
t1^
t-
fl
U <
C ^
0 H
1 i
S i
f
• o
B M
0 Q
i 2
M »
H U
8
M Cj Cj
«-t m in o o m in o -H o tn
*-C-'^«5M>iS3.
n 1- fl k« IB 3 «*IJJ«-I~H «'OKOi C^Ja^H
(
u y *p
n M jj -on
5 M S "° S &
JJ * W i § •- Qi
« V Qt u e o n
. § 1 * I » *
5O O o
IS. -2
ill f
i
> 1 * S
in
o o e o
e o e o
-i
s S^-
•85 • i * 8
•H • 1 » 4 £
b O O -H u —
Ob b — u
25 5 S3 S
u * * J5 M J5
lilp^frjf
„
-------
i
g
Fj
5?
§3
H O
gl
§ -
4J
| "
|E
gs
as
§ 1
||
w
1
ndards
•>)
* 5
*!
u n
R«lavan
(Units
m
|
(J
•D
>ss
111
-H « U
III
e
o
•H
•H
U
U
in
2
§
•H
S
u
il
9 *•
•* I
* c
•o »
H V
c •
* *
V) k
U
ID IN (N O *O *4 4oo*e *"* *^ t
. . || |
<~ •* « 00 1 t £ 0 _
U Id X Q O O QtC v
U O 4J U ti U 1 9 • •• O M • — ' • *"•
H « -i • — o o «c-ocl«c— c M>JQ
— • « £ 0 -H ~H u «j H C « -H £ -«-• g
ecu ki • j: £ +i.chi»*tft«wu— — ooH
« C » 10 -D U U «JJO*3^>i— 3 IA W —
C N r-t • ki ^H -H -H -H 4J«*44J^«Oi O — C — ' « ^
*-)«>«««UUCO-UB-UC(NUUJJ +J * TJ d. « «1 • D "9 N
^S^n'sNS'oJS^iiHifNir^tH-H •• C Oi O ^ •'^5oiO"^^^*
«J34J*J-H^j=T3^ c ^H c ^ u CE^HCC^ Q<0 C *-i*;W C
** O • JS * *J *• - * -Hie ttJIOUjlXSO -*4X
u H £ U *H • *4 f-i *^ >o« BUUMcGi/iH taoi
0
-t • b
n *J **
4J 4J U
£ SJS
t
£
.
o
u
-H n
•e u
*l O
• u
3 bt
-1 •
•
1
o
i
b
1
2
1
*
.s|
S.S
u°
4.2
•H «
M
u a
2 8>
gb
S
• u
«3
-------
RIATE
«D LIMITATIONS
S 3
cu «ti
7 3*e
^ £ 1 1
< ft H @
U 0* M
3a.
39
1
B
3
^ — .
S j
« j
U
S«
» *
S-
M
•o
\ c «
4> * -U
-H 4
J3 4J -H
S Si
5.8
L-H a
*" *
g
•H
+J
a
-H
Ll
U
n
S
§
-H
5
u
. g
c treatment or
Is proposed for
Lanca site.
No groundwat*
reinjection i
the Sierra BJ
!
i
i
M -O
U kt
O (7*
25
§^
u e
1,2
n u
O «
U
•:
%
0
1
« .2
Q S r
0 O
• t? wild - iugj"4«-H
£ • « • L, 1 U « e 0 «j 3 -i c TI u* ow
u • ^ ewn o c < o - H o 3 £-HW •
•H£unw c 4 • « • ne--e&u u « e
« u T) « • 3 -i u « £ "US9I ° " *; " -i
i j « ^ c in^vie-B -H 3 p i i- i ! £ * •
• e«D< e eokin 73 u H e • o -O.ee -H
bZbi^-»4 klUWQiOtbO 0 kt*O-f4 4J3nV
o 0.6 a •* X ~> & t 2 t, S - •-. £ u -ici
iu«u ee 3M33C-U oeeon oo«4OH
o -o u -o & o S 5 « « » £ 5. H i c e wuiu-ne
men e u -H > e I * o a e«u
« in « e b «i TJ -H o>nee o *J j>« M
n b ^i £ 1 1 be Ob ^^+J* *W'H^-H^
3 • -o IT w eoeSuue b ueno bbei.
ue-4 JB w -H-H.C « - 5 -6 e w J • 1 1 u
m « w -H c *J «i « c 4J K u 13 i J5 ••< > T3 u • e e
e>y«-H e J o « • «i eoL b -H e e H 3 -8
jj i 3 « ntr H 3 r ••< 3 • o *> tr ibeu-^
« c u &• w e b • *j & -o w . " -i « b jj u e -^ «
c u o n c « u « « J M c o « c « " - 1 • S
oiuv)o
II! !
e in • 4J
u b c e u
S S ^5l2 2a-So.
u 4J tn«JiDM • C - v O *
5 C.«S ulS?-§.S
e Hoen -ieU4J
S - U .2 n-H-HUO-HTJ
3 ».• -HO H u e Di'H ••< r a * •'< x >•
in o oa a o £ 3 o Q t u i T: c £
'
fM in
0 O
7 "7 S
^
g
g g §5
s •s & ill
p; • u Ob
i * e a o •
p « 54 fi5"4
OU -" _b O < M b
il i n M >1
i 2 O tfin 2 E K M
1 ' . '
-------
g
o
g
g
! 3
si
g »
S M
7 8*8
< S u £
t- n g n
W K S
5 O CD
i
H (2
Si
3 z
G
u
£
•8
U
S »
5 *>
• 'H
c
I
o
V
T5
licabla/
•vant am
ropriata
Isl
g
•r*
•rt
U
U
«
2
•M
4J
•H
U
«
Jg
e >>
S^
• »J
•H '•
" 0
•o -
• li
fl *•*
** -H
S* | U
« * O
4J O ^ f «> *U
— 4 W -H « ^ Si •
« 3 4J U -H O ^H Wl
S5§"° ~| .g|
w'£g5 S'-SS^
o f u a
o en J v u jj c JJ •
M
t <
O M
g .
n
•^
^
« f
« i
hi 4J
s 5
V
-------
8.3.1 CONTAMINANT-SPECIFIC ARARS
The contaminant pathways of concern are dermal exposure to and
inhalation and ingestion of contaminated soils and waste material.
Solid Waste Disposal Act
The Solid Waste Disposal Act (SWDA), as amended by the Resource
Conservation and Recovery Act (RCRA) of 1976 and the Hazardous
and Solid Waste Amendments (HSWA) of 1984, defines, under
Subtitle C, those solid wastes which are subject to regulations
as hazardous wastes. Municipal waste and waste from the
extraction, beneficiation, and processing of ores and minerals
(i.e. mine waste) are specifically excluded under Subtitle C.
Subtitle D requires States to develop solid waste management
plans and establish criteria to identify unsafe solid waste
facilities or practices.
Mine waste may be subject to RCRA Subtitle C requirements
to the extent that it is RCRA listed or RCRA characteristic
waste and provided that these wastes were disposed after
the effective date of the RCRA requirement. RCRA wastes
have been identified at the Sierra Blanca site, and at
least some disposal of the mine waste was after the
effective date of the first RCRA technical requirements,
i.e. November 19, 1980. Thus, RCRA Subtitle C is a
relevant and appropriate requirement, especially if
remedial action is taken which constitutes treatment,
storage, or disposal of these wastes (as defined by RCRA).
8.3.2 LOCATION-SPECIFIC ARARS
Physical characteristics of the site influence the type and location
of remedial responses considered for cleanup. The location-specific
ARARs identified for the site in Tables 8-1 and 8-2 establish
8-18
-------
consultation procedures with Federal and State agencies and may impose
constraints on the location of remedial measures or require mitigation
measures.
The location-specific ARARs relate to historic preservation, fish and
wildlife, wetlands, floodplains, and work in navigable waters. The
location-specific ARARs influence the type and location of remedial
alternatives developed for the site. No location-specific ARARs have
been identified for the Sierra Blanca site.
8.3.3 ACTION-SPECIFIC ARARS
Action-specific ARARs set controls or restrictions on particular kinds
of activities related to management of hazardous substances,
pollutants, or contaminants. These requirements are not triggered by
the specific chemicals present at a site but rather by the particular
remedial activities that are selected to accomplish a remedy.
Potential action-specific ARARs which deal with requirements for the
degree of treatment for remediation and disposal of contaminated
groundwater or surface water are listed in Tables 8-1 and 8-2 as
neither "applicable" nor "relevant and appropriate", since site
activities have not resulted in contaminated groundwater or surface
water.
Solid Waste Disposal Act (SWDAl
General RCRA Requirements - The Solid Waste Disposal Act
was amended by the Resource Conservation and Recovery Act
(RCRA) to control hazardous substances. The provisions of
RCRA pertinent to the Sierra Blanca site have been
promulgated under 40 CFR Parts 257, 260, 261, 262, 264,
268, and 280. EPA has determined that the above
regulations are "applicable11 to RCRA characterized and
listed hazardous wastes (40 CFR Part 260), which either:
8-19
-------
1) were disposed at a site after November 19, 1980; or 2)
the CERCLA remedial action consists of treatment, storage,
or disposal as defined by RCRA (40 CFR Part 264) . In
addition, these regulations are "relevant and appropriate"
to RCRA hazardous wastes disposed at a site prior to
November 19, 1980. "•
Some of the contaminants of concern at the Sierra Blanca
site are listed in Appendix VIII of RCRA (40 CFR Part 261,
App. VIII) and the wastes were disposed on-site after
November 19, 1980. Therefore, the RCRA regulations are
directly "applicable" for any future remedial action
involving treatment, storage, and disposal as defined by
RCRA. These regulations are "relevant and appropriate" for
any other activities resembling RCRA regulated activities.
However, currently, "waste from the extraction,
beneficiation, and processing of ores and minerals" (40 CFR
Part 261.4, 6, 7) is excluded from regulation under RCRA.
^
RCRA permits are not required for portions of CERCLA
actions taken entirely on-site. Therefore, administrative
RCRA requirements (i.e. reporting, record keeping, etc.)
are not "applicable" or "relevant and appropriate" for on-
site activities. However, all hazardous wastes disposed
off-site are required by CERCLA I21(d)(3) to be in
compliance with all pertinent RCRA requirements.
RCRA Treatment Requirements - CERCLA 121 establishes a
preference for remedial actions involving treatment that
permanently and significantly reduces the volume, toxicity,
or mobility of the hazardous substances, pollutants, and
contaminants at a CERCLA site. The RCRA requirements are
"applicable" at a site if: 1) the waste is hazardous; 2)
the treatment complies with the RCRA definition contained
in 40 CFR 260.10; and 3) the special jurisdictional
8-20
-------
prerequisites in the pertinent subpart for each category of
treatment are satisfied. Otherwise, the RCRA requirements
are "relevant and appropriate".
RCRA Disposal Requirements - EPA has defined disposal under
RCRA to be the movement (grading, excavation, etc.) of a
RCRA hazardous waste originally disposed before the 1980
effective date of RCRA from within a "unit area of
contamination" and placed in another location outside the
"unit area of contamination". The RCRA requirements are
"applicable" to activities of this type, and "relevant and
appropriate" to similar activities.
In the case of the Sierra Blanca site, as with many CERCLA
sites, there is no defined RCRA type "unit", but rather an
"area of contamination" with differing waste types and
levels of contamination. Therefore, excavation, treatment,
and encapsulation conducted within the site would be within
the "area of contamination" and not conform to the RCRA
definition of disposal. The RCRA requirements are not
"applicable". Any transport of wastes off-site do fall
under the definition; the RCRA requirements are
"applicable" in this case. The RCRA requirements may be
"relevant and appropriate" for on-site activities. Using
the disposal requirements in this manner requires the
"design and operating" RCRA requirements. These include
design requirements for landfills (including waste piles
during construction), surface impoundments and land
treatment units.
Land Disposal Requirements - The disposal of RCRA hazardous
waste during the course of remedial action may also be
subject to the special restrictions on land disposal of
hazardous waste established by the Hazardous and Solid
Waste Amendments of 1984 (HSWA). According to HSWA, all
8-21
-------
RCRA hazardous wastes are to be reviewed by EPA to
determine if they should be banned from land disposal.
Banned waste cannot be placed in or on the land unless they
have first been treated to levels achievable by best
demonstrated available technology (BOAT) for each hazardous
constituent in the waste.
EPA has defined placement and disposal to be identical.
Whether the land restrictions are "applicable" or "relevant
and appropriate" depend upon the disposal factors
previously discussed. Any on-site excavation, treatment,
or encapsulation of waste at the Sierra Blanca site does
not follow the RCRA definition of disposal. Therefore,
placement does not occur and the land disposal restrictions
are not "applicable", nor are they considered "relevant and
appropriate" until the EPA promulgates BOAT standards for
RCRA soil and debris. However, any waste transported off-
site for disposal does comply with the RCRA definition; the
RCRA requirements are "applicable" in this case.
8-22
-------
9.0 REMEDIATION ALTERNATIVES
9.1 REMEDIAL ACTION OBJECTIVES
To meet the overall objective of protecting human health and the
environment, specific remedial action objectives are developed for
contaminants of concern (COCs) within affected media. Remedial action
objectives are defined in this section as either the chemical specific
ARAR or the risk-based action level, whichever is more stringent.
Based on sampling data and the Risk Assessment presented in Section
6, the contaminant of concern at Sierra Blanca is lead, with minimal
additional health concerns associated with arsenic and other metals.
As discussed in Section 8.2, a chemical specific action level of 500
ppm for lead is considered appropriate at Sierra Blanca. Only in
those areas of the site where lead levels are high are other metals
concentrations also elevated. Thus, by approaching the site
remediation in a manner to address those areas where lead is found at
concentrations above 500 ppm, elevated concentrations of arsenic and
other metals will also be addressed.
The contaminated areas of the site consist of material piles of
partially processed ore and tailings, tank sediments, discharge pit
sediments and surficial soils. No subsurface soils or groundwater
have been found to be contaminated, and there is no surface water on
or near the site. Pene.1J.auion measures will, therefore, be limited
to the distinct on-site contaminant source areas, collectively
referred to as the Sierra Blanca waste material.
9.1.1 CHARACTERISTICS OF CONTAMINATED MATERIAL
Based on the results of the RI, the contaminated areas at Sierra
Blanca are shown in Figure 9-1, and some of the characteristics of
those areas are presented in Table 9-1. The contaminated material is
located in five material piles of partially processed ore and
tailings; sediments from three discharge pits and a cinder block
9-1
-------
PROCESS
BLDG. 1
INSET
LEGEND
^••MBI^HB
WASTE MATERIAL WHICH PASSED TCLP
WASTE MATERIAL WHICH FAILED TCLP "FOR LEAD
-X— SITE BOUNDARY
MP ORE PILE
TS TANK
SS CONTAMINATED SOIL
ESTIMATED EXTENT OF AREAS WITH
LEAD CONCENTRATIONS GREATER THAN 500 PPM
•CAMP DRESSER & McKEE INC.-
-------
TABLE 9-1
CHARACTERISTICS OF CONTAMINATED MATERIAL
Volume Arsenic Lead
Unit / Sample No. fC.Y.) mo/Kg mg/Kg
MATERIAL PILES
MP-01 120 52.1 18,900
MP-26 53 51.7 18,700
MP-02 4 «- 18,300
MP-03 2 — 16,320
MP-32 3 — 13,850
DISCHARGE PIT SEDIMENTS
DP-01 167 7,850
DP-03 128 22.3 9,050
DP-04 30 79.6 5,140
SURFICIAL SOILS
CBT 21 49.2 5,420
SS-02 15 25.5 10,409
SS-05 5 48 1,360
TANK SEDIMENTS
TS-01
TS-02
TS-03
TS-04
TS-05
TS-06
TS-07
TOTAL VOL./AVG. CONC. 570 47 8,950
3
1
1
1
2
2
10
1,510
51.4
148
5,160
83
66.5
143
14,100
5,520
3,728
46.400
12,600
9,490
1 1 ,500
n
-------
trench; surficial soils in two areas where contaminated runoff or
spillage occurred; and fine textured sediments from seven separate
tanks.
9.2 GENERAL RESPONSE ACTIONS
The general response actions identified for the Sierra Blanca site
which will meet the remedial action objectives, or will provide a
baseline against which actions may be compared, consist of the
following:
No Action. This response is identified for the purposes of
establishing a baseline with which to compare other general
response actions. There are no preventative or corrective
actions taken as a result of this general response action;
however, monitoring of the contamination may be prescribed.
Institutional Controls. This response utilizes actions
which control human contact with the contamination rather
than remediating the contamination itself. These actions
may be physical, such as fences or barriers, as well as
legal actions and zoning actions.
Containment in Place. As a general response action,
containment prevents risk to human health and the
environment by restricting contact or migration of the
contaminants via soil, water, or air pathways. A number of
technologies and different materials are available for use
in establishing migration barriers. Containment in place
is distinct from general response actions which require
excavation of the contaminated material, such as landfill
disposal.
Treatment. This action involves removal of the contaminant
from the contaminated media, or alteration . of the
9-4
-------
contaminant to reduce its toxicity, mobility or volume.
This general response action is usually preferred unless
site or contaminant specific characteristics make it
unrealistic.
• • Disposal. This action involves the transfer of
_ contaminated media, concentrated contaminants, or treated
material to a site reserved for long-term storage of such
materials. Disposal sites are strictly regulated in the
-^
; operation and types of materials they may accept.
""* These general response actions are developed in the following
*
"J sections.
!"»
*"•*
iu 9.3 IDENTIFICATION AND SCREENING OF REMEDIAL ACTION TECHNOLOGIES
•^
^ A number of potentially effective technologies are associated with the
general response actions selected for the site. In this Section,
( remedial action technologies potentially feasible for the Sierra
"* Blanca site are identified and subjected to preliminary screening,
"1 which consists of evaluation on the basis of technical feasibility
~* considering site conditions and characteristics of the waste.
«*•*
f The technologies considered potentially applicable to the Sierra
_ Blanca site are listed iv» Table 9-2. A discussion cf the technologies
H and process options associated with the general response actions, and
the results of preliminary screening, are presented below.
*"1
{
L*
9.3.1 NO ACTION
•»•**
'. I
""" The NCP (1990) requires that No Action be evaluated as a potential
1 remedy for all media types. The No Action alternative serves as a
-. *
— baseline for comparison of other alternatives. No Action means that
no remedial activities would be conducted to remove or reduce the
— hazards on the site. Monitoring may be conducted, however, to
tfi 9-5
-------
r Consideration
£
Required
Feasible
Feasible
Feasible
Feasible
e Without Prior
tlon Due to
•H *4
n
4J U
d Character-
Source Areas
« 0
timber
istics
e Without Prior
~4
J3
in
«
2
tion Due to
d Character-
Source Areas
Is °
^ kl «
0 J U
Feasible
Feasible
8
o ,§ 2 "•
fi « u a c «
e^g.".
2 3 1J 2 "8 H
•v4 X -H -H V)
S •« 8 • 8
e a a • a "
h. T « k. « 3
5C -HO
M 4J O tfl
i £
e Due to Low
1 Insufficient
u
S . !
a|.
|«:
e Due to Low
1 Insufficient
5s
•H W
•< k, « -H
1 U Q
'2
•
—1
J3
•H
i
2
e
a> u
e a
•»4
b ^4
£5
« n
0 O O O
*•* O 4J U
nil
e >. • >.
3 -H 2 -tJ
•*4 X H M
in « in •
« -H « -1
*" U 4J O
2 2
s-
fcs
s
§
JJ
Vego
§ 5
>
3
I -
i -H
ti
2
VI O
I u
S fr
I
k §
2
I
|
5
b
C
-------
u.
= 7
TABLE 9-2
FICATION AND SCREEN
DIAL ACTION TECHNOU
SIERRA BLANCA SITE
(Continued)
P
M
3
«
V)
cr
c
|
u
I/I
E
0
Process Opti
o
o
u
£
IS
•3
i
c
c
4.
u
4
U
e
&
u
a
0
• c
So
•H in
•u «
» « H
-H 4J 4J
.0 e -i
« . . "SIS
a 5 a 2-s.a
ia w ID • - H
! I I 1M
— 1 IA
a- i
u ^
•H a
fN
S^
a u H
§« • -o
-< -c C
•H 4J 4J « VI
4J H -H H kj 4J
IB «J ^H 4-1 IM
•c ^ -H a — H
H 3 *• 3 » j:
•H tn -o to u
-------
quantify the impacts associated with no remedial response.9.3.2
9.3.2 INSTITUTIONAL CONTROLS
Institutional controls potentially feasible for the Sierra Blanca site
consist of access restrictions, deed notices and zoning restrictions.
Access restriction is aimed at preventing human exposure to
contaminated waste material. This option typically consists of
installation of signs warning of the potential hazards associated with
the site, together with barriers, such as fences, to restrict site
access. These measures are technically feasible.
Use restrictions would involve deed notices and zoning ordinances to
regulate use of the property. Deed notices would permit notification
of potential buyers of the property about past activities at the site.
Zoning would allow classification of the site to restrict permissible
uses. These measures are technically feasible.
9.3.3 CONTAINMENT IN PLACE
Containment technologies are remedies that employ a barrier to limit
the mobility of a contaminant. The containment technologies
considered in this section are limited to those which do not require
excavation of the material. On-site disposal alternatives consisting
of excavation, consolidation and disposal are evaluated as disposal
options in subsequent sections.
Containment in place may consist of either capping the waste material
or providing a means of preventing the spread of windblown dust.
Capping controls include clay covers (RCRA cap), soil cement covers,
bituminous pavement, and soil covers. Dust controls consist of a
vegetative mat which is established on the waste material to prevent
wind erosion. For tanks, capping would consist of providing a sealed
cover. Waste material at the Sierra Blanca site is located in
9-8
-------
numerous different source areas which include waste piles, open pits
and trenches, flat expanses of surface soils, and open tanks and
process equipment. Some of these open tanks are located within
buildings, and capping controls would be impractical or cumbersome to
- implement. Due to the number, dispersal, and individual
-J characteristics of the source areas, technologies that provide
_ containment in place without some associated excavation and
consolidation are not considered feasible, and are eliminated from
further consideration. Consolidation of the material and disposal on-
1 site is feasible, however, and is discussed in subsequent sections.
,**
""? 9.3.4 TREATMENT
-i
r$ Treatment technologies that are potentially feasible for the Sierra
'' -t
ij Blanca waste material are fixation, extraction, reprocessing, and
_^ biological and thermal techniques.
o
Fixation
~
-J
Fixation technologies applicable to mining and milling wastes include
1 neutralization and solidification; the latter also being referred to
""' as physical encapsulation or immobilization. Neutralization involves
— the addition of materials with large acid neutralization capacity,
— such as kiln dust, which raises the pH of an acidic environment with
^ the aceoiupaiiyinc, fixation of metals as ip.etelljc hydroxides.
r_ Solidification consists of the fixation of contaminant metals by
chemical binding and physical encapsulation from the addition of
rj
> solidification agents, which make the contaminants unavailable to
I*.
oxidation and leaching.
«»•»
~* As discussed in Sections 4 and 7, Toxicity Characteristic Leaching
•"•» Procedure (TCLP) analyses was conducted on the various types of waste
— material at Sierra Blanca, as part of the XRF program. The findings
of the TCLP analyses indicate that material piles (MP-01, MP-02, MP-
„ 03, MP-26 and MP-32) which consist of crushed ore material, and
.-» 9-9
-------
contaminated tank sediments (TS-01 through TS-07), do leach
significant quantities of lead when subjected to TCLP test conditions.
Arsenic and barium, which were also analyzed per TCLP, are far below
regulatory limits. Notably, contaminated discharge pit sediments and
contaminated soils subjected to TCLP analyses, did not result in the
leaching of any of the tested constituents above regulatory limits.
This indicates that contaminated discharge pit sediments and soils at
Sierra Blanca will not be classified as RCRA hazardous wastes, but the
tank sediments and contaminated material piles do exhibit RCRA
hazardous waste characteristics with respect to leaching potential.
Based on the TCLP results, fixation processes may be applicable to
contaminated material piles and tank sediment at Sierra Blanca, but
may not be necessary for the contaminated soils and discharge pit
sediments.
*
Neutralization
Neutralization of acid formation in the waste material, which results
in inhibition of contaminant mobility, can be achieved through the
addition of sodium compounds, such as soda ash, or calcium containing
materials, such as lime, cement kiln dust, or fly ash.
To determine if neutralization is a feasible response action,
neutralization bench scale testing is currently being performed on
representative samples of the waste material. The results of the
bench scale testing are to be presented as an addendum or supplemental
report. At this time, it is assumed that neutralization is a viable
treatment alternative, and this technology is retained for further
evaluation.
Solidification
Several processes have been developed to immobilize metals in soils
by solidification. These involve mixing the contaminated soils with
9-10
-------
cement or proprietary chemicals to solidify the mass and prevent
leaching of metals. In addition to Portland cement, solidification
agents include thermoplastics and organic polymers. Many of these
treatments are combined with acid neutralization, which will
~- immobilize the metals through conversion to insoluble carbonate and
- hydroxide forms, as well as encase them in a solidified mass.
—^
Pilot testing of solidification treatment methods are required to
^ determine the feasibility of this response action. If the solidified
j material passes the toxicity characteristic leaching procedure (TCLP)
test, then treatment is successful and the material is suitable for
"^ unclassified disposal. To assess the feasibility of solidification
L4
as a treatment option, bench scale tests are being performed on
•3 representative samples of the Sierra Blanca waste material. Since the
** volume of the waste material potentially requiring solidification is
*, comparatively small (225 cy) , the use of a proprietary solidification
nj process is not cost effective. Based on interviews with
representative vendors, it appears that 8,000 to 10,000 cubic yards
•^^
i of material are necessary to warrant mobilization of proprietary
^
fixation treatment process equipment. For this reason, bench scale
7? testing of solidification treatment is limited to Portland cement of
** various mix compositions.
*•**!
«•" The results of the bench scale testing will be presented as an
~> addendum or supplemental report. Since cement solidification is
L feasible, this technology is retained for further evaluation.
r?
ij Extraction
f? Extraction process options for Sierra Blanca waste material include
•^
soil washing and soil flushing. Both remove leachable and/or
f* extractable contaminants from the soil matrix. The ability of these
processes to lower the concentrations of metals depends on the
characteristics of the waste material and the contaminants.
Contaminants which are incorporated into the soil matrix are not
9-11
*_-
-------
readily available for extraction processes. For example, lead
contamination in tailings from mining and milling operations is
commonly incorporated into crystal matrices, which would also be the
case for unprocessed ores. Without other physical treatment, only the
amorphous form of the metals may be recovered. Since this is also the
form that would leach from contaminated soils, removal of this
fraction would be protective of human health and the environment.
Extraction processes may, therefore, be feasible for the material pile
and tank sediment materials that failed the TCLP test.
Soil Washing
Soil washing would involve the addition of acidic or chelating agents
to excavated waste material to bind the metal contaminants. The
physical process of mixing usually occurs in mobile units and helps
to distribute the chemicals, enhance binding, and remove the chemical-
metal complex from the soil. The washed material together with liquid
contaminated with chemical-metal complexes are then separated from the
solution by pH dependent treatment processes, depending on the
chemical agent used. Following dewatering of the metal complexes, a
sludge exists for disposal as hazardous waste. The liquid may be
regenerated for further use or disposal to a Publicly Owned Treatment
Works (POTW).
Soil washing would be feasible to implement although equipment
requirements are substantial. Equipment requirements for a soil
washing process would include a screen, chemical storage and feeding
equipment, mixing tanks, clarifier, and dewatering equipment. Water
separated from the process could be discharged to the Carrizozo POTW,
and dewatered sludge containing the metal complexes would be
transported to a hazardous waste landfill. The equipment requirements
for soil washing are greater than other feasible soil treatment
processes, such as fixation. This process also suffers from the
disadvantage that a separate liquid waste stream is created. Also,
the effectiveness of soil washing as a treatment option cannot be
9-12
-------
properly evaluated without bench and pilot scale tests. Due to the
relatively small volume of material present at the Sierra Blanca site,
and the complexity associated with a soil washing process and likely
high costs, this technology is eliminated from further consideration.
Soil Flushing
*•«
\ Soil flushing uses the same processes as soil washing for chemical
v^l
binding, treatment of the contaminated liquid, and separation of the
^f metal complexes from the liquid. It is an in-situ process, and
*
^ differs from soil washing in that the mixing process occurs through
**» injection of the washing solution directly into the unexcavated
•«* material, rather than in mobile units or tanks. Removal of the liquid
^ with complexed metals is then accomplished through the use of
^ extraction wells and infiltration galleries. The advantage of this
option is that excavation of the material is not required.
•""»!
_i
For the Sierra Blanca site, the waste material is located in numerous
"7 different source areas, some of which are in the form of above grade
""" material piles or tanks which contain contaminated sediments. Soil
— flushing process options would not be feasible for the above ground
— material. The remaining waste material is characterized by relatively
-Y thin layers of surficial soils. Given the shallow depths
J (approximately two feet) , and the fact that this material is not
contiguous, installation and operation of injection and extraction
H wells would not be practical. For these reasons, soil flushing
process options are eliminated from further consideration.
Reprocessing
r-»
*~ Reprocessing wastes to extract recoverable metals, and render the
waste non-hazardous in the process, is a response action that has been
— evaluated for other EPA Superfund sites involving mining and milling
r* 9-13
-------
wastes. This remedial technology generally consists of establishing
a milling process on-site or transporting the wastes to an operating
facility. Processes normally considered include pyrometallurgical
(smelting process) or hydrometallurgical (chemical leaching or froth
flotation process).
For the Sierra Blanca site, there is insufficient volume of waste
material to consider implementation of an on-site reprocessing option.
For off-site reprocessing, the only waste material which would be
potentially suitable would be the material piles and perhaps some of
the tank sediments. These materials contain a metals content
sufficiently high to possibly make them acceptable to a smelting
facility. The contaminated surficial soils and discharge pit
sediments have generally low level metals contamination and, if
excavated, would contain impurities such as organic matter and debris.
This material would not be acceptable to existing smelting or metals
refining facilities for reprocessing. Although the material piles and
tank sediments comprise only about 225 cubic yards of material, this
technology is attractive since it may be very simple to implement.
Additionally, this response action could work well in conjunction with
another remedial technology for the discharge pit sediments and
surficial soils.
To investigate the feasibility of off-site reprocessing of the ores
and tank sediments, a survey of metals sine] tin? end refining
facilities was conducted. The operations manager of the nearest
operating lead smelter to the site was contacted to discuss the
reprocessing option. After having a sample of the Sierra Blanca waste
material assayed for precious metals and lead content, the operations
manager determined that he was not interested in accepting the
material for reprocessing.
Biological
Biological treatment technologies are commonly applied to treatment
9-14
-------
of organic contaminants. For inorganic contaminants, biological
methods have been used in wetlands treatment systems for acid drainage
from tailings piles and to remove metals. For the metals
contamination in the ores, tank sediments, and surficial soils at the
Sierra Blanca site, biological treatment would have a very limited
potential. One recently developed technology involves seeding the
waste material with special surfactants which inhibit the growth of
iron bacteria, the metal/pyrite oxidizers which create acids. This,
in turn, enhances the growth of sulfate reducing bacteria which
converts acids back into pyrite materials.
In this treatment method, the material is consolidated, graded, and
seeded with the surfactants in capsules which provide a timed release
over an approximate three-year period, and which should be effective
in reducing iron bacteria for seven years. After seven years,
revegetation can start acting as a control on the recurrence of the
bacteria by inducing genesis of a normal soil that naturally controls
the iron bacteria. This occurs through the generation of natural
organic acids and the presence of beneficial heterotrophic bacteria
that compete for nutrients with the iron bacteria.
While promising, biological treatment of tailings and soils with
metals contamination has not been proven in full-scale applications.
Thus, the long-term effectiveness of this technology is unknown. Due
to the many uncertainties currently associated with this technology,
and the small volume of waste to be treated, biological treatment of
Sierra Blanca wastes is eliminated from further consideration.
Thermal
Thermal treatment process options applicable to tailings and surficial
soils with metal contamination are in-situ vitrification and
pyrolysis. In-situ vitrification is a thermal treatment process that
converts contaminated solid material into a chemically inert and
stable crystalline product. It is a technology that is potentially
9-15
-------
applicable to immobilize contaminants in the waste material at the
site. Pyrolysis utilizes extremely high temperatures in the absence
of oxygen to dissociate wastes into their component atoms. Cooling
results in recoverable streams of metals, siliceous materials, and
gases. This process option is technically feasible for the metals
contaminated waste material on the site.
Both the in-situ vitrification and the pyrolysis process would be
difficult to implement for treatment of Sierra Blanca wastes. Both
processes are complex to construct and operate, both have extensive
equipment requirements, and both would produce gas sidestreams which
would require further treatment. Additionally, the availability of
services, equipment, and skilled workers for these processes is
limited. Costs to implement either option would be very high compared
to other feasible treatment technologies. For these reasons, neither
in-situ vitrification nor pyrolysis are feasible, thus thermal
treatment of Sierra Blanca wastes is eliminated from further
consideration.
9.3.5 DISPOSAL
Disposal technologies potentially feasible for the Sierra Blanca waste
material include consolidation and disposal on-site, excavation and
removal to an off-site municipal or hazardous waste landfill, or
excavation and disposal in an abandoned nine shaft. These disposal
options may be implemented in association with fixation and
reprocessing options previously discussed.
On-Site
Whereas containing the wastes in place by capping, vegetative mats,
or other means is not feasible due to the number and character of
individual source areas on the site, consolidating the wastes in a
central on-site location would be feasible in conjunction with
suitable controls to prevent the spread of contamination. Disposal
9-16
-------
of the material on-site would be protective of human health and the
environment with a properly designed containment cap over the pile,
or with fixation processes to address leachable materials.
-; Given the characteristics and climate of the Sierra Blanca site, an
4
- appropriate disposal location could consist of an unlined cell with
-» a soil cover, and monitoring wells. This design would prevent
intrusion of surface water into the fill, and allow for periodic
monitoring of the groundwater at the site.
i
If the wastes which have been found to be characteristically hazardous
7 by the TCLP tests are not treatable by fixation or reprocessing, then
a RCRA Subtitle C-compliant landfill, or RCRA vault, would be relevant
5 and or appropriate, unless a variance to the Land Ban (40 CFR Part
•* 268) regulations were granted by EPA and the State of New Mexico.
„ This- landfill would have a double liner, leachate collection system,
4 impermeable cap, surface water run-on/run-off controls, and
groundwater monitoring system. Due to the extensive construction and
operational standards associated with these facilities, the relatively
low volume of contaminated material present, and the availability of
other RCRA Subtitle C-compliant hazardous waste landfills within
reasonable distances, construction of an on-site RCRA vault for Sierra
Blanca wastes is not considered feasible, and is eliminated 'from
further consideration. However, construction of a RCRA Subtitle D-
compliant landfill is feasible and is retained for further
consideration.
Off-Site
The off-site disposal options for Sierra Blanca waste materials are
municipal or hazardous waste landfills or abandoned mine shafts.
Municipal Landfill
The wastes may be disposed of in a municipal landfill if they are not
9-17
-------
characteristically hazardous. However, the municipal landfill must
also be willing to accept the waste. Several landfill operators in
the vicinity of the site were contacted to determine if the Sierra
Blanca wastes are suitable for disposal in their facility. Even
though much of the waste has been determined to be non-hazardous, per
TCLP, and other wastes may be treatable by fixation processes prior
to disposal, some operators are unwilling to accept Superfund wastes
in their municipal landfills. Other operators, however, would be
willing to accept the waste provided it was certified as non-
hazardous, and provided this method of disposal is acceptable to the
State of New Mexico and EPA. Municipal landfill disposal, therefore,
appears to be feasible and is retained for further evaluation.
Hazardous Waste Landfill
Characteristically hazardous wastes must be disposed of in a hazardous
waste landfill, unless a variance to RCRA regulations is given to the
wastes by EPA and the State of New Mexico. The closest Suitable
permitted hazardous waste landfills that would accept the wastes are
located in Nevada, Utah, and Colorado. Given the availability of
these facilities within reasonable transportation distance from the
Sierra Blanca site, this disposal option is retained for further
evaluation.
Abandoned Mine
Another possible disposal option consists of excavating the waste
material and disposing of it in an abandoned mine in the vicinity of
the site. An initial criterion for the acceptability of a potential
mine disposal site is that the proposed repository should be above
seasonal high groundwater levels in the mine to prevent the
possibility of leaching.
To assess the feasibility of this approach, the New Mexico Abandoned
Mine Lands Bureau was contacted, as this agency would have regulatory
9-18
-------
authority over any potential mine disposal site. After considering
this method of disposal, the Abandoned Mines Bureau determined that
they would not be able to accept Superfund wastes at their abandoned
mines sites. Disposal of Sierra Blanca waste material in an abandoned
mine is therefore eliminated from further consideration.
9•4 CRITERIA FOR ALTERNATIVES DEVELOPMENT
In evaluating and screening technologies, the process options
associated with the technology types determined to be potentially
feasible are evaluated and screened in terms of relative
effectiveness, implementability, and cost. Primary emphasis of the
evaluation is placed on effectiveness in protecting human health and
the environment; however, implementability and cost evaluations are
also important. Each of these three evaluation criteria are described
briefly below.
Effectiveness
Specific process options that have been identified should
be evaluated with respect to their effectiveness relative
to other process options within the same technology type.
This evaluation should focus on the following (U.S. EPA,
1988):
1) The potential effectiveness of process options in
handling the estimated areas or volumes of media and
meeting the contaminant reduction goals identified in
the general response actions;
2) The effectiveness of the process options in protection
of human health and the environment during the
construction and implementation phase; and
3) How proven and reliable the process is with respect to
the contaminants and conditions at the site
• Implementability
Implementability encompasses both the technical and
institutional feasibility of implementing a technology
process. Technical implementability is used as an initial
9-19
-------
O
u
JJ
•*4
npleaentabil
w
ictiveness
w
144
U
in
Proces:
Option
- &
« 0
11
" u
e
S §
I-5
a
•
1
-
>
3 &
a o
hi jj
4J 4
01 — 1
l!
e w
hi » JJ
f« tj
-1 «
E
0
H
JJ
O
1
a
H
u
a a
«
- jj >
u
J"
j2
0
i
B
S
g
Jj
y
§
•H
*5
4J
•H
Cb
35
!g
residents to
:ate; may be
Lly unpopula
»53
£ £5
f B
JJ 1 O
B *
JJ O JJ
JJ 0 U «
ixposure threi
it ion; would i
i appropriate
laterial excai
W ^ JH E
« TJ H tr
u $ 3 c
•§ "*
s;sl
T) B U u
3 hi u o
«
I
§
JJ -H
!!
V) —t
£S
S
o
H
jj in
3 -H
JJ O
4J JJ
in e
S3
Q.
O
JJ
25
« O
^
o o
r B
residents to
:ate; may be
Lly unpopula
o «
9 ~* U
e • o
o
jj
JJ
ixposure threi
its; would not
.nation
9 S
• •On
> H JJ
8U B
« 0
« hi U
hi
o « e
X B h.
Permanent
A
JJ
••i
a £
a 3
u o
11
_•
a
Lly implemen1
•o
3
in
a
i exposure thi
:cess
N a
o<
•H E
B -H
H JJ
si
Ijp
Fencing
in
§
jj
u
in H
in w
« jj
U in
5
•H
•H
I
JJ
•g
1
81
••4
>,
3
e
•
hi «
3 T3
u in
O JJ W
0 -H
Sw B h.
•H TJ •
in ~* w
6 ^ |
JJ «
E B
in « •-<
•O U 4J
e o e
Oi *u jj
2 . a
in
u
jj
§
•c
i
in
0
u
H
JJ
• in
«
JQ
• H
•H
J5
J3
IB
JJ
.ly implemen<
•o
(K
Ul
§T3
•H •
•H 3 hi
led by regulat
ictiveness; we
:ential exposi
o u g
-4 e
« a
JJ U
•3 .•€
3 -1 »
JJ M hi U)
3« o -H
1 B h.
Zonxng
Ordj nances
a
M
U
a
JJ £
« ^i
u o
21
.» o^
e B
11
jj n
.ly implement
1 require en
res
« 3 °
•H n
reducing toxic
if contaminant
M w
B >•
e -^
53
28
•w *0
u
o.
u
jj £.
2g
11
jj
•g
4J
B
1
>H
•3
i
•H in
reducing toxic
>f contaminant
B ><
•H JJ
•H
• -H
53
S8
»! -o
S S
B
O
Solidifica
jj
u 5
j O
3 g
e
•g
JJ JX
]h
n
>i «
•-« u
•H O
•3 °
• o
OJ u
• hi
^J M
rendering wast
and in recovi
B 3
•H H
W 0
U B
a
0«
B
•H
tn
0
hi
a
£
m
1
1
n
ffective Cor
Ls
e H
o
M m
•• -H
V) U
^H -H
JJ M
S 3
8-5
u o
« 0
a a
•s!
n
e t
« u
s {j
nantable if
lot characte
f hazardous
Is?
•H
reducing mobi:
:s
B S
H B
•M
e •
> o
•H JJ
!§
U 0
Q
e
J
RCRA Subti
Landfill
e
•H
Ul
1
g
^
•
8.
n
0
a
S
o
jj _
A C
So
in
• 1
jJ -H
0) JJ
Sw
•H
hi
imentable if
lot characte
f hazardous
w »1 HI
8-2^
H « U
•H
reducing mobi:
:s
B 3
•H B
e •
> «
?1
9 U
IM
U O
Q
e
•H
RCFA Subti
(Municipal
Landfill
e
•H
*H
O
*4
JJ
'a
u 5
Jg, O
38
e
•g
^H
•3
1
•*
i
S
1
• «
B S
•H E
H
• •
> ia
•p4 JJ
4J B
U 0
e u
u 'o
U -1
e -H
S 3
RCRA Subti
(Hazardous
W«=te) Lin
-------
screen of technology types and process options to eliminate
those that are clearly ineffective or unworkable at the
site. Therefore, this subsequent, more detailed evaluation
of the process options places greater emphasis on the
institutional aspects of implementability, such as the
ability to obtain necessary permits for off-site actions,
the availability of treatment, storage, and disposal
"; services (including capacity) , and the availability of
necessary equipment and skilled workers to implement the
_ technology.
Cost
~
.J Cost plays a limited role in the screening of process
options. Relative capital and operations and maintenance
,*» (O&M) costs are used rather than detailed estimates at this
* stage in the process. The cost analysis is based on
*"•* engineering judgment, and each process is evaluated as to
whether costs are high, low, or medium relative to other
£J process options in the same technology type that achieve
•j the same degree of protectiveness.
; Screening of the feasible technology process options on the above
basis is conducted in order to identify processes representative of
-; the particular response action. This screening process is
~ illustrated in Table 9-3.
1
"* 9.5 DEVELOPMENT OF REMEDIATION ALTERNATIVES
— In developing remediation alternatives for the Sierra Blanca Site,
„_ general responds actions were combined using technologies developed
i__ and summarized in Table 9-3. The Alternatives considered feasible and
suitable for continued evaluation are described below.
n
VJ
Although No Action does not achieve the remedial action objectives,
^ this alternative is required for consideration. No action, while not
w involving remediation of the waste material, will require some level
n of cost to implement which are evaluated in Section 10.
"it
Of the Institutional Controls available, only access, land use, and
— deed notices are considered appropriate. These restrictions will be
— 9-20
I
-------
relatively simple to implement, as zoning regulations already exist
in Carrizozo, and adding access controls and deed notices should hot
be difficult. Relocation of resic^nts, either on a temporary or
permanent basis, should not be necessary, as adequate measures can be
provided to protect nearby residents during site remediation
activities.
Feasible treatment alternatives for this site are limited, and only
solidification fixation using Port:-ind cement or similar compounds
appears feasible at this time. F isults of bench scale tests on
neutralization processes, currently underway, may also demonstrate the
suitability of this approach. Both r eutralization and solidification
require similar remediation activit es, and are expected to provide
a similar level of treatment at simi .ar costs. Thus, for the purpose
of development and detailed evaluation of alternatives, only one of
these treatment methods is evalue ;ed. Cement solidification is
selected for more detailed evaluat n; chemical neutralization will
not be further considered unless the bench scale test results indicate
that greater treatment efficiency or equivalent treatment efficiency
and cost advantages are possible using this technology.
Disposal alternatives include on-site disposal in an RCRA Subtitle D-
compliant landfill, which would require treatment of the leachable
material (material piles and tank sediments) prior to disposal. Off-
site disposal in a municipal landfill would be feasible provided the
leachable material is first treated. Otherwise, the material would
require disposal in a hazardous waste landfill.
Considering the above requirements, the feasible treatment and
disposal technologies are combined into Alternatives 3, 4, and 5, as
shown on Table 9-4. These alternatives are evaluated in detail in
Section 10.
9-22
-------
TABLE 9-4
SIERRA BLANCA SITE
REMEDIATION ALTERNATIVES
Alternative
DejscriDtion
1. No Action
2. Institutional Controls
3. Cement Solidification / On-Site
Disposal
Cement Solidification / Off-Site
Municipal Landfill Disposal
Off-Site Municipal and Hazardous
Waste Landfill Disposal
No action to reduce the toxicity, mobility,
or volume of contaminants
Access, land use, and deed restrictions
Excavate contaminated material; treat
teachable material piles and tank
sediments by cement solidification;
dispose on-site
Excavate contaminated material; treat
teachable material piles and tank
sediments by cement solidification;
transport to and dispose in municipal
landfill
Excavate teachable material piles and
tank sediments; transport to a permitted
hazardous waste disposal facility.
Excavate non-leachable surficial soils .
and discharge pits; transport to and
dispose in municipal landfill
-------
10.0 DETAILED EVALUATION OF ALTERNATIVES
A total of five alternatives for the Sierra Blanca site remediation
are analyzed in detail in this section. The alternatives that are
evaluated consist of the following:
Alternative 1 - No Action
Alternative 2 - Institutional Controls
Alternative 3 - Cement Solidification/On-Site Landfill
Disposal
Alternative 4 - Cement Solidification/Off-Site Municipal
Landfill Disposal
Alternative 5 - Off-Site Municipal and Hazardous Waste
Landfill Disposal
10.1 EVALUATION CRITERIA
Each of the above alternatives are described in this Section by
providing the following information, as appropriate:
Detailed description of remediation activities
Treatment schematic
Size and configuration of remediation components
Trciluiant rates
Space requirements
Site layout
On-site and off-site activities
Required permits
Time frame required to achieve remediation goals
Detailed capital and O&M costs
Present worth of remediation costs
The detailed evaluation process is a structured format, designed to
provide relevant information needed to adequately compare and evaluate
10-1
-------
feasible alternatives to allow selection of an appropriate remedy for
the site by EPA through the Record of Decision (ROD) process. The
remedy must meet the following statutory requirements:
Be protective of human health and the environment;
• Attain ARARs (or provide grounds for invoking a waiver);
• Utilize permanent solutions and alternative treatment
technologies or resource recovery technologies to the
maximum extent practicable;
Satisfy the preference for treatment that reduces toxicity,
mobility, or volume as a principal element, or provide an
explanation in the ROD as to why it does not; and
i
• Be cost effective.
Nine evaluation criteria have been developed by EPA to address the
statutory requirements listed above and to address additional
technical and policy considerations that have proven to be important
for selecting remedial alternatives. These criteria are listed and
briefly described below:
Overall Protection of Human Health and f.he Environment -
How well the alternative reduces risks to human health and
the environment, through treatment, engineering or
institutional controls.
• Compliance with ARARs - How well the alternative complies
with all applicable or relevant and appropriate
requirements or, if a waiver is required, how it is
justified.
• Long-Term Effectiveness and Permanence - How well the
10-2
-------
alternative maintains long-term effectiveness in protection
of human health and the environment. Alternatives which
afford the highest degree of long-term effectiveness and
permanence are those that leave little or no waste at the
site.
Reduction of Toxicity, Mobility, or Volume through
Treatment - Anticipate performance of the specific
treatment technologies that an alternative may employ and
their ability to destroy or irreversibly treat
contaminants.
Short-Term Effectiveness - How well the alternative
protects human health and the environment during
construction and implementation of a remedy.
Implementability - Whether or not the alternative is
technically and administratively feasible, and whether or
not the required goods and services are available.
Cost - Analysis of capital and O&M costs of each
alternative to determine cost-effective remedies. Cost
estimates are developed with relative accuracy (-30 .to
+50%) and are presented as present worth costs so that
alternatives can be reasonably compared.
State Acceptance - To be completed for the most part after
the public comment period; this criterion describes the
preference of the State or support agency.
Community Acceptance - To be completed for the most part
after the public comment period; this criterion reflects
the preferences of the community.
Each of the five alternatives for Sierra Blanca contamination are
10-3
-------
individually evaluated then comparatively analyzed on the basis of the
first seven of the nine criteria above. The last two criteria (State
and community acceptance) will be fully addressed in the Record of
Decision (ROD) after the public comment period.
10.2 ALTERNATIVE 1; NO ACTION
10.2.1 DESCRIPTION
The No Action alternative (Alternative 1) provides a baseline for
comparing other remedial alternatives for the Sierra Blanca site.
Because no remedial activities would be implemented to mitigate
contamination present at the site under this alternative, long-term
human health and environmental risks for the site are as presented in
the baseline risk assessment in Section 6. Although Alternative 1
does not include any remediation of contamination, it would consist
of continued periodic monitoring of groundwater quality so that human
health and environmental risks posed by site contaminants could be re-
evaluated on a periodic basis.
10.2.2 CRITERIA ASSESSMENT
Alternative 1 is implementable; however, it provides no treatment,
engineering, or institutional measures to control the exposure of
receptcrs to contc*-ninated material. No rtduiTtjon in risks to human
health and the environment would occur.
No controls for exposure, other than the existing fence, and no long-
term or short-term site management are included under Alternative 1.
This alternative provides no reduction in the toxicity, mobility, or
volume of the contaminated ores, tank sediments, and surficial soils
on the site. All existing and potential future risks associated with
the site would remain. With respect to groundwater, no effects from
site contaminants have been detected. With respect to soils,
quantifiable risks are present which consist of hazards arising from
10-4
-------
potential exposure to lead, with limited additional effects from other
metals (Section 6) .
Alternative 1 would not provide any increased protection to human
health or the environment, and it would not be in compliance with
ARARs due to requirements imposed by RCRA Subtitles C and D regarding
disposal of mining wastes, and due to New Mexico solid waste
regulations.
10.2.3 COST ESTIMATE
Although Alternative 1 is to provide no action, some expenditure of
capital costs would be required. These would be for installation of
two additional monitoring wells on the site. These wells would be
required together with the existing wells to allow proper long-term
monitoring of the groundwater which flows away from the site.
Indirect capital costs are also required for engineering and design
of the monitoring well installation, contingency funds,
mobilization/demobilization costs, and associated legal and regulatory
costs. These indirect capital costs are included as an estimated
percentage of the direct capital costs in all of the remediation
alternative cost estimates.
Annual operation and maintenance (O&M) costs would include semi-annual
groundwater sampling and analysis for TAL metals for an estimated 30-
year period. Indirect O&M costs include administration costs and a
maintenance reserve and contingency fund.
The estimated present worth cost for Alternative 1 is $48,000 and is
detailed in Table 10-1. The present worth cost is based on an assumed
life of 30 years and an annual interest rate of 9 percent.
10-5
-------
^ ^™ "^
Hii
cr.
c
'C
S
ffi
73
$
Description: Periodic grounc
Interest Rate: 9%
Level of Accuracy: +50% to -30%
DIRECT CAPITAL COSTS
^ r~
^8
Q. O
O
t- H
^ w
lo
o
t-
z
§
t
z
COST
COMPONENT
ct o
0 0
0 0
ci o"
*
0
o
o
in
CM
o
(0
LU
Install Additional Monitoring Wells
TOTAL DIRECT CAPITAL COSTS
INDIRECT CAPITAL COSTS
o o
in in
t* ^
O O O|
o o eg
in in qt
*1
_
3^
s
V*-
1. Engineering & Design (15%)
2. Contingency (25%)
3. Other Indirect Costs
a. Legal (5%)
b. Regulatory (5%)
c. Mobilization/Demobilization
Ql
a
y
CA
TOTAL INDIRECT CAPITAL COST:
o
0
q.
£
{•
UJ
oc
a
+
H
^^
UJ
TOTAL CAPITAL COSTS (DIR
-------
UJ
0<
II
-Q1"??
o2fc^
LU
_l
m
52
UJ
LL
Sfjg
SI8
£ CO
>- -^
H- CC
< LU
^ Q-
O ~
O
LU
O
UJ
cc
LL
o
u
U
LU
cc
5
§
in
o
CM
O
CO
o
o
0
§
O
83
in irt
O O
co co
o
o
o
o
V*
0
o
o
CM"
o o
s
s
CM
m
3
C
ra
o>
co
LU
en
'55
ta
Sampling/
ra
•o
o
6
co
&
O
O
15 "m
c
CO (0
UJ UJ
co
fc
3
{2
cCC
18"
18 C C
i= <0 «
« c o>
c 5J c
'E E c
l^o
c
UJ
CC
0
u.
o
|
H
UJ
CO
LU
CC
D_
J
<
H
E
a
i
0
ESENT
E
a
_i
<
O O
= T- CM
-------
10.3 ALTERNATIVE 2: INSTITUTIONAL CONTROLS
10.3.1 DESCRIPTION
Alternative 2 consists solely of institutional control measures
designed to isolate receptors from site-based risks. Under this
alternative, no actual remedial measures to directly address the
contaminated material on the site are implemented; rather, legal
controls, such as land use and access restrictions, are employed to
minimize the likelihood of receptor contact with contaminated media.
Continued monitoring of groundwater as described for Alternative 1 is
also included as a part of Alternative 2 to ensure that the risks to
human health are being addressed by the institutional controls.
Institutional controls considered feasible for the Sierra Blanca site
are access and land use restrictions. Access would be restricted by
provision of new site fencing to replace the existing barbed wire
fence, plus appropriate signage to warn of the hazards on the site.
Land use restrictions would consist of altering the zoning in
accordance with the existing City of Carrizozo zoning ordinance to
limit permissible uses of the site. Deed notices would consist of
recording an appropriate notice with the County of Lincoln to alert
parties interested in the property of the hazards contained on the
site. These restrictive measures may also be included as elements of
ct/.ir iciiie.<3iation alternatives.
10.3.2 CRITERIA ASSESSMENT
The use of institutional control measures provides a greater degree
of protection of human health than the No Action alternative alone,
since institutional actions can reduce the potential exposure of
receptors. Access and land use restrictions further limit activities
on the property which would minimize exposure risks. While some
degree of human health protectiveness would be provided by Alternative
2, it would not be protective of the environment since the
10-8
-------
contamination would remain.
Like Alternative 1, Alternative 2 would not comply with ARARs due to
requirements imposed by RCRA Subtitles C and D regarding disposal of
mining wastes, and due to New Mexico solid waste regulations.
Although reduction in the potential for human exposure would be
recognized under this alternative, only limited long-term
effectiveness would be provided due to difficulties in enforcement.
Additionally, this alternative provides no reduction in the toxicity,
mobility, or volume of contaminants at the site. Alternative 2 may
k
also be difficult to implement, since it may be unacceptable to the
State of New Mexico and to the residents of Carrizozo.
10.3.3 COST ESTIMATE
Capital expenditures under this alternative include costs for warning
signs and additional fencing, and administrative costs for deed
notices and zoning restrictions. Additionally, as continued
groundwater monitoring is a component of this alternative, the
installation of two additional monitoring wells is included. Indirect
capital cost items include engineering and design, contingencies,
legal, regulatory, and mobilization/demobilization.
Annual costs associated with this remedial action are associated with
semi-annual grouncLuetiPr sampling. Indirect annual costs, include
administration, contingency, and maintenance reserve.
The present worth cost estimate for Alternative 2 is $119,000 as
detailed in Table 10-2. The present worth cost is based on a life of
30 years and an annual interest rate of 9 percent.
10-9
-------
co
O
cc
Z-UJ
CO CO >
< Z CC
H" ^
CM 2
LU2
> n
ee
LU
M
O
'•g
'C
i
3
•g
JS 8?
! 2
o 3^ m
< en +
1
.ill
ts°
11!
DIRECT CAPITAL COSTS
< CO
t O
3:°
o
i— b.
5 CO
z g
3o
>
2
8
t
Z
o
COST
COMPONENT
o
o
o
o
3
CM
0»
O
in
CM"
LL
j
o
o
o
o
_
»-
CO
i
§fjt
—L ^
T- g
O O
o o
o o
i-"in
i- CM
CO ™
JLU
J2
1. Access Restriction
a. Fencing & Signs
2. Land Use Restrictions
a. Deed Notices
b. Zoning Restriction
3. Install Additional Monitoring We
s
o
CM"
TOTAL DIRECT CAPITAL COSTS
INDIRECT CAPITAL COSTS
o o
0 O
en co
£<°
1 . Engineering & Design (7%)
2. Contingency (15%)
o o o
o o o
oo ao >n
CM CM W
_
0
^— '
3. Other Indirect Costs
a. Legal (5%)
b. Regulatory (5%)
c. Mobilization/Demobilization
i
a
8
CO
TOTAL INDIRECT CAPITAL COST
o
o
0
s
V*
£
IU
cc
5
Z
+
&
IU
TOTAL CAPITAL COSTS (DIR
-------
CO
d
CC
LU
< K
zco
mco> §
CC
Q.
^
5
0.
<
i
H
Ul
CO
IU
OC
o.
CM
-------
10.4 ALTERNATIVE 3; CEMENT SOLIDIFICATION/ON-SITE DISPOSAL
10.4.1 DESCRIPTION
Alternative 3 involves treatment of the contaminated waste material
on the Sierra Blanca site, followed by on-site disposal. Treatment
would be accomplished by a fixation process using Portland cement to
solidify the waste material. Non-leachable wastes (as per TCLP
results) present on the site would not require treatment. After
treatment, both wastes types would be disposed in an on-site landfill.
A schematic of Alternative 3 is shown on Figure 10-1.
As discussed in Section 9, fixation is the only suitable treatment
technology that is feasible for the wastes, and the cement
solidification process appears to be the most appropriate fixation
process. Results of ongoing bench scale studies of both Portland
cement solidification and chemical neutralization fixation processes
will likely confirm this assumption; however, in the event that
neutralization is found to be more effective, neutralization would be
implemented in lieu of cement solidification.
Treatment of Sierra Blanca waste material is applicable to only the
leachable fraction, i.e., that portion of the waste which did not pass
the TCLP tests, and which therefore would be expected to leach lead
to the envi rMiir.tnt. Tbe wastes which failed the TCLP tests are the
material piles and the tank sediments. Contaminated surficial soils
and soils within the discharge pits successfully passed the TCLP tests
(although they remain hazardous due to other potential receptor
exposure pathways besides leaching, such as ingestion). This non-
leachable fraction, thus, does not require further treatment; however,
the non-leachable wastes must be disposed in an acceptable manner.
Minimum standards for land disposal of the non-leachable wastes are
considered to be those contained in RCRA Subtitle D. After fixation
treatment, the leachable wastes will be rendered non-leachable, and
may then also be disposed in accordance with RCRA Subtitle D
10-12
-------
o
f=
!
o
o
CO
10
Ld
o:
o
1
o
en
s
o
-------
(municipal and industrial solid waste) standards. A summary of both
the leachable and non-leachable contaminated material quantities on
the Sierra Blanca site are provided on Table 10-3.
~ Final disposal of the treated wastes (leachable fraction) and the
J untreated wastes (non-leachable fraction) under Alternative 3 would
be on-site. Construction standards for the on-site landfill would be
determined during the remedial design phase prior to implementation,
and would be developed in accordance with Federal and State ARARs.
1
i
~j
RCRA Subtitle D-compliant landfills are designed on a site-specific
~| basis, and for this site it is assumed that appropriate controls would
be provided by a simple subgrade, waste material repository, and soil
9? cap. No impermeable liner in the landfill should be necessary as the
If'S
& treated waste material would be non-leachable, and the landfill could
_ be constructed well above seasonal high groundwater levels.
J Additionally, application of the Hydrologic Evaluation for Landfill
Performance (HELP) computer model (Section 2.5.1) predicts minimal
percolation of precipitation to groundwater at the site. The landfill
lu>
cap would consist of a layer of topsoil to prevent access to the
~"; contaminated material within the landfill. The cap will be graded to
""* promote runoff of stormwater, and external storm water controls, such
~ as drainage swales, would be constructed to keep storm water away from
— the landfill. Monitoring wells would also be provided around the
.., landfill to verify that leaching of contaminants is not occurring
j based on periodic sampling. A representative section for a RCRA
Subtitle D-compliant landfill considered appropriate for the Sierra
Blanca site is depicted on Figure 10-2.
Implementation of Alternative 3 would consist of leasing a standard
portable concrete mixer and setting it up on the site. Portland
cement of a type to be determined based on bench scale tests would be
purchased and stockpiled on-site, together with any supplemental sand
or aggregate required to achieve the mix design. The contaminated
material piles and tank sediments would be excavated and discharged
10-14
-------
TABLE 10-3
SIERRA BLANCA SITE
CONTAMINATED WASTE MATERIAL QUANTITIES
Est. Vol. Estimated
Source Area (C.Y.) S.G. Mass m
1. LEACHABLE MATERIAL*
Material Piles 182 3.00 460
Tank Sediments" 43 2.65 96
Subtotal 225 556
2. NON-LEACHABLE MATERIAL*
Discharge Pits and 345 2.65 770
Surficial Soils
TOTAL 570 1,326
* Per TCLP test (see Section 4.6)
** Includes cinder block trench sediments
C.Y. = cubic yard
S.G. = specific gravity
T =ton
-------
:
Ft
I o
o z
UJ
cc
o
o
U) _l
UJ ^
li
tniQ
3°
g i
(/)UJO
U
-------
into the cement mixer where the material would be mixed with Portland
cement, water, and any supplemental sand or aggregate required. The
resulting concrete mixture would then be deposited in the on-site
landfill (Discharge Pit 1). Non-leachable contaminated surficial
soils and sediments within the contaminated discharge pits would be
excavated and deposited directly without treatment. The discharge pit
would then be capped.
10.4.2 CRITERIA ASSESSMENT
Alternative 3 would be highly protective of human health and the
environment, since the wastes would be treated to the extent
practicable. Additionally, this alternative would achieve compliance
with all ARARs. Long-term effectiveness and permanence would also be
achieved. Durability tests are being conducted on the solidified
material as part of the bench scale treatability tests. This
information will be helpful in further evaluating the long term
effectiveness of this option.
Alternative 3 would reduce the toxicity and mobility of the wastes
through treatment; however, the volume of the wastes would not be
reduced. Implementation of this alternative should provide a high
degree of short-term effectiveness, provided appropriate precautions
and control measures such as dust control are instituted during the
remediation phase.
Implementation of this alternative is possible without undue technical
or administrative difficulty.
10.4.3 COST ESTIMATE
Capital expenditures under this alternative include costs for leasing
a cement mixer, solidification materials costs, and remediation site
work. Additionally, as continued groundwater monitoring is a
component of this alternative, the installation of two additional
10-17
-------
monitoring wells is included. Indirect capital cost items include
engineering and design, contingencies, legal, regulatory, and
mobilization/demobilization.
Annual costs associated with this remedial action are associated with
annual groundwater sampling for the first five years after remedial
site work, then continued groundwater sampling once every five years
for twenty five years. This lesser amount of long-term groundwater
monitoring than assumed for Alternatives 1 and 2 is considered for
Alternative 3 since the contaminated source material will be
remediated under Alternative 3. Indirect annual costs include
administration, contingency, and maintenance reserve.
The present worth cost estimate for Alternative 3 is $79,000 as
detailed in Table 10-4. The present worth cost is based on a life of
30 years and an annual interest rate of 9 percent.
-»
10.5 ALTERNATIVE 4; CEMENT SOLIDIFICATION/OFF-SITE MUNICIPAL
LANDFILL DISPOSAL
10.5.1 DESCRIPTION
Alternative. 4 involves cement solidification fixation treatment of the
leachable fraction of the Sierra Blanca waste material, followed by
transportation together with excavated non-leachable wastes to a
suitable off-site RCRA Subtitle D-compliant landfill for final
disposal. Alternative 4 is similar to Alternative 3, except that
final disposal of the wastes would be in an off-site landfill. As
discussed in Section 9, one qualified off-site landfill which appears
willing to accept the wastes is located 160 miles from the Sierra
Blanca site near Albuquerque. Transportation of the wastes would be
accomplished in standard public highway-approved bulk carrier trucks,
of approximately 40,000 lb. capacity, which would be covered to
prevent generation of airborne contaminants. After disposal of the
wastes in the landfill, management of the wastes would become the
10-18
-------
4i
'(O
§
CD
OT
T3
1
I
•o
15
o
QL
£
I
O
1
o
O O O
o o o
in
o>>
™ rS
0)0
!™
s
Cement Mixer Lease
Purchase Portland Cement
Excavate Leachable Waste Ma
T-
cvi co
in
OJ
CM
>
0
=
Solidify Leachable Material witl
Cement; Place in On-Site Land
*
4
CO
N
>
6
"co =
•C T3
Excavate Non-Leachable Mate
Place Directly into On-Site Lam
in
«- CM
CO a
^LU
JO
^n
Earthwork/Grading
Install Additional Monitoring W<
cb r^
TAL DIRECT CAPITAL COSTS
O
)IRECT CAPITAL COSTS
^
Engineering & Design (20%)
Contingency (15%)
Other Indirect Costs
^ c\i eo
?
o
a. Legal (5%)
b. Regulatory (5%)
c. Mobilization/Demobilization
CO
TAL INDIRECT CAPITAL COST
O
t-
§
LU
OC
5
z
+
H
O
HI
cc
5
CO
^
0
o
_i
E
0
_i
<
o
h-
•i
'55
o
0)
5
0}
I
I
T3
8
o
X
03
o;
1
Q.
0)
S>
ra
HI
'•6
_c
«
£
co
-------
21
o
o
o
in
o
o
o
in
§
in in
UJ
o
eo
o o
eo m
g
flllS
UJ
QUJ
o
0
o
o
o
> O
' O
> in
=; w
^O
3 O
o
o
o
12
(0
&
in
CO
CC
UJ
tn
O
O
O
5
o
£
UJ
Q.
O
UJ
oc
5
^ »-*
1- QC
C V
Z" K
~ ~-
< UJ
8-
v^
o
UJ
2
UJ
OC
U.
t
D
COST
COMPONENT
,
'
~ca
a
c
c
03
'£
0)
CO
ra •
UJ
CO
"«0
t
<
I
Q.
CO
£
CD
•D
3
8
0
CO
fc
0
O
DIRECT PERIODIC
§
CO
CO
o
o
0
Q
o
\^
cc
UJ
Q-
G
UJ
cc
Q
&
PRESENT WORTH
1
(A
CO
O
U
O
5
o
5
CT ANNUAL/PEI
UJ
C
5
^_ ^_
To 15
3 3
C C
C C
< <
(0 CO
UJ UJ
inistration
itenance Reserve 4
tingency
p C C
£« §
<50
to
£
8
g
g
cc
UJ
~J
^
D
Z
<
O
UJ
cc
5
&
PRESENT WORTH
1
g
CO
O
U
*•"*
U
o
o
£
Ul
Q.
_J
Z
z
<
+
<
E
<
0
E
PRESENT WOR
_i
g
Q)
>.
1
I
o
I
C
m
s,
0>
1.
(0
10
ra
1
o>
"5
c
<
I
= T- CM
-------
responsibility of the landfill operator. For this reason, the
operator has stated that the landfill would accept the wastes only if
approved by EPA and the State of New Mexico, and only if the wastes
are certified as non-hazardous as per RCRA.
10.5.2 CRITERIA ASSESSMENT
As with Alternative 3, Alternative 4 would be highly protective of
human health and the environment since the wastes would be treated,
and compliance with ARARs would be achieved. A high degree of long-
term effectiveness and permanence would be provided since an
appropriate municipal landfill is frequently monitored. Additionally,
this alternative would achieve a high degree of permanence.
Alternative 4 would reduce the toxicity and mobility of the wastes
through treatment. Implementation of this alternative should provide
a reasonable degree of short-term effectiveness, provided appropriate
precautions and control measures are instituted during the remediation
phase. These measures would be those that minimize or prevent
exposure hazards to on-site workers and nearby residents during
remediation activities.
10.5.3 COST ESTIMATE
Capital costs for Alternative 4 include excavation of the contaminated
material and associated site grading, on-site cement solidification
fixation treatment of the leachable fraction of the wastes, and
transportation of the material to a municipal landfill. Estimated
tipping fees required by the landfill are also included.
Additionally, as continued groundwater monitoring is a component of
this alternative, the installation of two additional monitoring wells
is included. Indirect capital cost items include engineering and
design, contingencies, legal, regulatory, and
mobilization/demobilization.
10-21
-------
Annual costs associated with this remedial action are associated with•
annual groundwater sampling for the first five years after remedial
site work, then continued groundwater sampling once every five years
for twenty five years. This lesser amount of long-term groundwater
monitoring than assumed for Alternatives 1 and 2 is considered for
Alternative 4 since the contaminated source material will be
remediated and removed from site under Alternative 4. Indirect annual
costs include administration, contingency, and maintenance reserve.
The present worth cost estimate for Alternative 4 is $235,000 as
detailed in Table 10-5. The present worth cost is based on a life of
30 years and an annual interest rate of 9 percent.
10.6 ALTERNATIVE 5; OFF-SITE MUNICIPAL AND HAZARDOUS WASTE
LANDFILL DISPOSAL
10.6.1 DESCRIPTION
In lieu of treatment of the leachable fraction of the Sierra Blanca
waste material, an alternate approach would be to dispose of it in a
hazardous waste landfill. Alternative 5, therefore, consists of
excavating the leachable wastes and transporting them without
treatment to a suitable hazardous waste landfill. Because there is
no requirement to dispose of the non-leachable wastes in a hazardous
waste landfill, these wastes would be excavated, kept segregated from
the leachable wastes, and transported to a municipal landfill for
final disposal.
Suitable hazardous waste landfills are available in Nevada, Utah, and
Colorado. A preliminary estimate of hazardous waste landfill disposal
costs was developed based on the Colorado facility, as it is the
closest to the Sierra Blanca site. When contacted, the hazardous
waste landfill in Colorado expressed an interest in accepting the
wastes and provided a budget estimate for tipping fees.
10-22
-------
0)
I
CT
J
< 53 E
c £ ^ -|
*^ ^^ Ui "
II fc
lit
re
I IIIIIlI
o
Q
1
<
Q.
O
o
o o o o
o o o o
o oo *— oo
in to
«/»
o
8
o
(O
O O O r-,
o o o §
CM O O §
oo m" •» c
CM CM "
05
^ cc
O o-
t-
LU
2
LU
O
LU
CC
LU
(0
(0
o
o
_l
t
E
o
S
in
cc
5
o o
o
o
o>
m
o co
'-CM
o o
o o
00 00 i
r-~r-~i
o
o
q
a
o
o
o
o
CM
o in (o o
o i- m
o
in
O IT)
r~ CM
in 04
o
CM
in o
i- O
- - .
in »- in
-
•? 8
!ll<
«
*°
LU
CC
5
z
ant Mixer Lease
lase Portland Cement
Jo
3
Q.
5
vate Waste Material
ify Leachable Material
Si
x o
LU CO
«_
re
S
•c
c a
(D (/)
el
Q) 2
Oh-
£
cipal Landfill Tipping F<
iwork/Grading
11
2 LU
1
& TCLP Analyses
II Additional Monitoring
||
CO
DIRECT CAPITAL COS
g
O
«
&
O
u
-1
5!
<
O
z
111
cc
3
z
neering & Design (7%)
ingency (15%)
r Indirect Costs
O.C ®
c o S
LUOO
• . •
I
"a
0?
_j
re
c
g
egulatory (5%)
lobilization/Demobilizat
QC 2
ri u
\u
&
INDIRECT CAPITAL CC
g
B
MM
5
CAPITAL COSTS (1
_i
O
T- CM CO •
m
-------
UJ
"X
LU Q
EEC
Q LU
LU
cr
HI
CO
£
o
o
o
5
o
£
UJ
Q.
u
<
3
O
UJ
cc
5
= CO
(- cr
o
LU
cr
LL
z
ENT
OS
§
O
O
o
o
\ri
o
co
0
o
o
o
o
o
o
0
o
in in
o o
co co
(^
in
CO
c
(0
CO
a
LU
CO
•55
"•5.
CO
CO
a
1
C
£ {2
£ 8
& «
B «
5 Q
\k 2
O K
P 8!
I <
s I
co ^
LU .
£ o
^ UJ
< £
15 "m
3 3
c c
co co
LU LU
(0
o
o
co ^
II
o £
8 S
= *
1
o
LU
CC
O
z
LL
O
$
O
cCC
^ m §
|| g
E •§ c
•o « o
<
a
o
c
o
I S
LU CO
CO UJ
LU tr
cr &
a.
O O
= i- CM
g
2
S
CO
>.
§
8
o
I
e
CO
£
o>
s.
CO
I
o
O)
1
c
<
i
-------
10.6.2 CRITERIA ASSESSMENT
Alternative 5 would be protective of human health and the environment
since the contaminated material would be removed from site and safely
disposed of. Compliance with ARARs would be achieved as disposal of
the wastes would be permitted under current regulations. A similar
degree of long-term effectiveness and permanence would be provided
with this alternative compared to on-site landfill disposal. Although
treatment would be provided prior to disposal in an on-site landfill,
the continuous monitoring and active waste management present in a
permitted hazardous waste landfill should provide a comparable level
of protectiveness. The long-term effectiveness and permanence of off-
site hazardous waste landfill disposal would be less than treatment
and disposal in a municipal landfill, since treatment of the wastes
would be provided prior to disposal in the municipal landfill.
Additionally, the level of waste management and waste monitoring
provided is comparable at both facilities. This alternative would
achieve a high degree of permanence since the wastes are removed from
the Sierra Blanca site.
Alternative 5 would reduce the mobility of the wastes as a result of
disposal in a hazardous waste landfill. However, the toxicity and
volume of the wastes would not be affected. Implementation of this
alternative should provide a reasonable degree of short-term
effectiveness, provided the appropriate precautions and control
measures are instituted during the remediation phase involving
excavation of the contaminated material.
10.6.3 COST ESTIMATE
Capital costs for Alternative 5 include excavation of the contaminated
material and associated site work, transportation of the leachable
fraction of the wastes to a hazardous waste landfill, and
transportation of the non-leachable fraction to a municipal landfill.
Confirmation of total waste removal would be conducted by analyses of
10-25
-------
lead in post-remediation surficial soils samples. Additionally, as
continued groundwater monitoring is a component of this alternative,
the installation of two additional monitoring wells is included.
Indirect capital cost items include engineering and design,
contingencies, legal, regulatory, and mobilization/demobilization.
*~i
Annual costs associated with this remedial action are associated with
annual groundwater sampling for the first five years after remedial
site work, then continued groundwater sampling once every five years
~~*- for twenty five years. This lesser amount of long-term groundwater
~ monitoring than assumed for Alternatives 1 and 2 is considered for
~~ Alternative 5 since the contaminated source material will be
> u
~ remediated and removed from site under Alternative 5. Indirect annual
-, costs include administration, contingency, and maintenance reserve.
, "*
j
_ The present worth cost estimate for Alternative 5 is $344,000 as
detailed in Table 10-6. The present worth cost is based on a life of
30 years and an annual interest rate of 9 percent.
4
Table 10-7 provides a cost summary of the five remediation
— alternatives for the Sierra Blanca Operable Unit (OU2) of the Cimarron
—• Mining Corporation NPL site.
10-26
-------
LU
CL
UJ
^
«c
^
.eg
1
'E
i
_c
g
*!<
*o
«*«
i
€
re
-T
C
i
0)
CO
(0
TJ
1
— — 1 (—
52 < c/3
re E o
0
0
"S
re
-c K t-
S Do
1
.t
1 ^
™ ^
o Z
cB <
~ 2
o O
V)
8.
ffi
E E
3 3
<« 55
Cfl M
*
§o o o o o o o
o o o o o o o
^ to in co in o o o
cftin ^ ^ T— in ^ o
«»m ^- CM T- CM '-
- ^
o " o>
:= (D :=
>• . 'E O i O{/5<0«
^^ o o &^ o ^^ ~^
s^. s
JJ
. Excavate Waste Material
. Transport Leachable Fraction
to Hazardous Waste Landfill*
. Hazardous Waste Landfill
Tipping Fee
. Transport Non-Leachable
Fraction to Municipal Landfill"
. Municipal Landfill Tipping Fee
. Earthwork/Gradity
. Lead & TCLP Analysis
Install Additional Monitorina We
»- CM co •«• m
-------
o
ts;
^o
3 o
cc
o
LU
o
LU
CC
LL
CO
fc
o
o
o
S
O
£
UJ
Q.
I]
<
3
Z
Z
<
U
ui
c
COST
COPONE
o
o
o
0
eo
o
UJ
«»
o
0
o
89
tn iri
o o
m m
o o
0 0
m in
o
8
o
in
CM
n
I
a
in
Ground Water Sampling/Analysis
CD to
3 3
C C
C C
«
CO
0
o
E
TOTAL DIRECT PE
^
cc
LU
0.
O
E1
Q
ft
i
^\
i
TOTAL PRESENT V
CO
CO
O
0
O
5
0
£
HI
a
<
Mk
INDIRECT ANNl
CO CO
UJ LU
1. Administration
00
i
s
2. Maintenance Re
Contingency
INDIRECT ANI
LL.
O
£
o
i
TOTAL PRESENT '
(CAPITAL +
f
CC
o
»-
TOTAL PRESEN
-------
TABLE 10-7
COST SUMMARY OF REMEDIATION ALTERNATIVES
Present
Alternative Wo1h CQSt
1. No Action $48,000
2. Institutional Controls 93,000
3. Cement Solidification / On-Site 79,000
Disposal
4. Cement Solidification / Off-Site 235,000
Municipal Landfill Disposal
5. Off-Site Municipal and 344,000
Hazardous Waste Landfill
Disposal
------- |