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DECLARATION FOR THE RECORD OF DECISION
SITE NAME AND LOCATION
Clear Creek/Central City Site
Clear Creek and Gilpin Counties, Colorado
Operable Unit No. One
STATEMENT OF PURPOSE
This decision document represents the selected remedial action for Operable
Unit No. One of the Clear Creek/Central City site developed in accordance
with the Comprehensive Environmental Response, Compensation and Liability
Act (CERCLA), as amended by the Superfund Amendments and Reauthorization
Act of 1986 (SARA), and to the extent practicable, the National Contingency
Plan.
The State of Colorado has been consulted on the selection of remedy. The
State of Colorado has neither concurred nor non-concurred on the selection.
STATEMENT OF BASIS
This decision is based upon the Administrative Record for Operable Unit No.
One of the Clear Creek/Central City site (the index of which is attached in
Appendix C). The index identifies the items which comprise the
Administrative Record upon which the selection of the remedial action is
based.
DESCRIPTION OF SELECTED REMEDY
Low pH mine tunnel discharge water is only one of several sources to the
degradation of water quality and aquatic habitat at the Clear Creek/Central
City site. Data gathered during the remedial investigation has shown that:
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0011273
o Runoff from tailings and waste rock, piles contain dissolved and
suspended metals.
o Tailings and waste rock piles adjacent to Clear Creek and North
Clear Creek are unstable and could collapse into the creeks. These
piles have the potential to produce acid. When introduced to water,
the pH will rapidly decrease and significant amounts of metals will
be released to the environment.
o Hydrostatic pressure will build up in the tunnels due to cave-ins.
After sufficient pressure has built up, the tunnels will blow out,
releasing large volumes of dissolved and suspended metals to the
creeks.
o The ground waters in the vicinity of the acid mine discharges are
contaminated.
o There are additional sources of low pH mine tunnel discharges and
tailings upstream of the site that could be contributing dissolved
and suspended metals to the streams.
All of the above factors contribute to water quality and aquatic habitat
degradation and will be studied in the following subsequent operable units:
Operable Unit No. Two - Tailings and Waste Rock Remediation
Operable Unit No. Three - Source Control
Operable Unit No. Four - Blowout Control
Operable Unit No. Five - Regional Ground Water Contamination
Operable Unit No. Six - Upstream Mine Discharges and Tailings
These operable units are subject to change.
The selected remedy for Operable Unit No. One of the Clear Creek/Central
City site consists of treatment to meet upstream water quality
concentration for contaminants of concern identified in the remedial
investigation (RI) in a treatment system discharge line. The upstream
water quality concentrations will be used as operational standards for this
interim remedy. The upstream water quality concentrations ("upstream
levels") consist of the geometric mean of the subset of RI samples taken on
Clear Creek immediately upstream of the discharge from the Big Five Tunnel
and on North Clear Creek immediately upstream of the discharge from the
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0011274
Gregory Incline. These upstream levels are not to be considered as final
applicable and/or relevant and appropriate requirements for the final site
remedy.
Because a determination of the final remedy is contingent upon the
completion of the other operable units listed above, the selected remedy is
an interim remedy. This interim remedy will consist of construction of
passive treatment systems to treat the low pH mine tunnel discharge from
each tunnel prior to discharge to surface waters. This is the preferred
alternative and is contingent upon the results of ongoing pilot plant
studies demonstrating that upstream levels can be met by a passive
treatment system. If the upstream levels cannot be met by passive
treatment, then either of the following treatment systems will be built:
o a combination system consisting of passive and active treatment
systems will be constructed. A phased approach to construction will
be utilized.
o two active treatment systems (chemical precipitation or
electrochemical precipitation) will be constructed to treat mine
tunnel drainage prior to discharge.
These systems will be designed to reduce the mobility, toxicity or volume
of dissolved and suspended metals in the mine drainage, increase pH, and
meet upstream levels. Upstream levels are listed in the Selected Remedy
section.
A pilot-treatment system for passive treatment has been constructed at tte
Big Five Tunnel. The pilot plant has been constructed to determine the
ability of passive-treatment effluent to meet upstream levels for the
discharge from a treatment facility at the end of the facility discharge
pipe. The pilot plant will also be operated to gather design data for
sizing volume requirements, determine optimum dissolved and suspended metal
removal for various organic and vegetation types and confirm removal
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0011275
efficiencies. Results of studies at the pilot plant will provide data
required in order to determine final design criteria. Siting studies will
evaluate alternate treatment site locations.
The remedy includes the following operation and maintenance activities:
Passive Treatment
o Annual collection of and laboratory analyses of soils and vegetation
to measure heavy metal accumulation.
o Annual maintenance of vegetation.
o Replacement of wetland materials and disposal and treatment of meial
saturated organic materials and plants every 5 to 10 years.
o Maintenance of pipelines carrying low pH mine tunnel discharge water
from tunnels to passive treatment systems.
Active Treatment
o Labor costs for operation and maintenance of the facility.
o Chemical costs and power costs for operation and maintenance of tte
facility.
o Sludge treatment and disposal costs.
o Maintenance of pipelines carrying low pH mine tunnel discharge waier
from tunnels to treatment facilities.
Passive Treatment and Active Treatment Combination
o The combination of costs listed above under passive treatment and
active treatment.
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0011276
DECLARATION
The selected remedy is an interim solution requiring the exercise of the
"interim remedy" waiver (Section 121(d)(4)(A) of SARA) from
contaminant-specific ARARs listed in the ROD Decision Summary. Location
and Action Specific ARARs will be met. The "interim remedy" waiver allocs
for the selection of a remedial action that does not attain ARARs if "the
remedial action selected is only part of a total remediation action that
will attain such level or standard of control when completed." Upstream
water quality concentrations have been selected as the operational standsrd
for the interim remedy. The interim remedy treats low pH mine tunnel
discharges in a treatment facility sufficiently to meet upstream water
quality concentrations in the treatment facility discharge line. Operable
Unit No. One for the Clear Creek/Central City site is only part of the
total remedial action required for the site. Future operable units are
expected to be completed within 18 months, at which time a final solutioi
will be proposed. The interim remedy is consistent with the final site
remedy.
In accordance with SARA section 121(d)(2)(A(ii), EPA intends that the
final remedy will at least attain water quality criteria established under
the Clean Water Act, where such criteria are relevant and appropriate uncer
the circumstances of the release. Additional data collection and analysis
are necessary for EPA to determine whether such national criteria are
relevant and appropriate under the circumstances of these releases or
whether site-specific modification to national criteria would more
appropriately establish a clean-up goal for this site. Until such time
that it is determined that site specific modification to individual
contaminant criteria are necessary, EPA will consider the more stringent of
human health or aquatic life ambient water quality criteria (AWQCs) as ar
ARAR for the final remedy. This interim remedy will provide protection c f
human health and the environment.
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0011277
It is determined that the remedy utilizes permanent solutions and
alternative treatment technologies to the maximum extent practicable.
Therefore, this remedy satisfies the preference for treatment that reduces
mobility, toxicity, or volume as a principal jeiement.
J* c fry
Darfe
Jan$es/3. Scnetfer
Regional Administrator
Environmental Protection Agency
Region VIII
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ADMINISTRATIVE RECORD
SF FILE NUMBER
I
0011278
ROD DECISION SUMMARY
TABLE OF CONTENTS
Section Page
I. Site Name, Location, and Description 1
II. Site History 3
III. Enforcement 13
IV. Community Relations History 14
V. Alternatives Evaluation 15
VI. Selected Remedy 26
Appendix A - Responsiveness Summary
Appendix B - Applicable and/or Relevant and Appropriate Federal and State
Requirements,
Appendix C - Index to the Administrative Record
Appendix D - State Concurrence With Remedy
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0011279
LIST OF TABLES
Table Page
1 Daily Discharge of Metals from Mine Drainages A
2 Mean Upstream Water Quality Concentrations 7
3 Summary of Risk Assessment 11
4 Comparison of Alternatives 27
5 Cost-Effectiveness Summary 30
6 Passive Treatment - Metal Removal Efficiencies 32
LIST OF FIGURES
Figure Page
1 EPA Study Area 2
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ROD DECISION SUMMARY
CLEAR CREEK/CENTRAL CITY SITE
OPERABLE UNIT NO. ONE
0011280
I. SITE NAME, LOCATION, AND DESCRIPTION
The Clear Creek/Central City site was nominated to the Superfund National
Priorities List (NPL) in 1982. The site is located approximately 30 miles
vest of Denver, Colorado and consists of the discharges of acid mine
drainage and milling and mining wastes from five mines/tunnels in the Clear
Creek and North Clear Creek drainages.
The Clear Creek/Central City site encompasses the northeastern portion of
Clear Creek County and southeastern portion of Gilpin County in the
northeastern portion of the Colorado Mineral Belt. Specifically, the focus
of the investigation was five abandoned mines/tunnels proximal to the
cities of Idaho Springs, Black Hawk, and Central City and the influence of
acid mine drainage from those tunnels on adjacent stream courses
(Figure 1). The tunnels are the Argo Tunnel and Big Five portals on Clear
Creek and the National Tunnel, Gregory Incline, and the Quartz Hill Tunnel
in the North Clear Creek drainage. The Argo portal is within the city
limits of Idaho Springs. The Big Five portal borders the Idaho Springs
city limits and is sitauted adjacent to a trailer court. The Gregory
Incline is within the Black Hawk city limits. The National Tunnel is
within a mile of the City of Black Hawk. The Quartz Hill Tunnel is within
a mile of the City of Central City.
Surface water contamination results from acid mine drainage emanating from
the five tunnels and from seepage of ground water through tailings piles
both proximal to these tunnels and along stream courses. Potential
contaminant receptors include inhabitants of the area, downstream surface
water and ground water users and wildlife, both terrestrial and aquatic.
Recent studies completed by EPA indicate that significant loadings of
-1-
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Figure 1 Clear Oeek/Central City Study Area
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0011282
dissolved and suspended metals (1,200 pounds per day, are discharged to the
Clear Creek, drainage from the five mine tunnels. A summary of this data is
listed in Table 1 and discharge concentrations from the tunnels are
compared against Federal Ambient Water Quality Criteria (AWQC) for aquatic
life. A summary of instream water quality concentrations immediately
upstream of the discharges from the Big Five Tunnel on Clear Creek and the
Gregory Incline on North Clear Creek is listed in Table 2. These dissolved
and suspended metal loadings have resulted in a significant depletion of
aquatic life and have potential impact to downstream users of surface and
ground water.
The acidity of the mine drainage is due largely to oxidized ground water
passing through ore zones dominated by iron-bearing minerals, primarily
pyrite. One method of forming acid mine drainage is sulfide oxidation
being catalyzed by aerobic bacteria, particularly the genus Thiobacillus,
resulting in the release of sulfuric acid and, consequently, further
mineral dissolution. Subsequent discharge from the tunnels releases
dissolved and suspended metals to Clear Creek and North Clear Creek,
adversely affecting water quality for downstream users.
II. SITE HISTORY
The Clear Creek/Central City historical hard rock mining site is one of the
most mined areas in Colorado. Data indicate that up to twenty-five (25)
mines and six (6) milling operations are currently operating in Gilpin and
Clear Creek counties. The area includes over 800 abandoned mine workings
and tunnels. The intensity of mining operations has varied in recent
years, due largely to fluctuating market prices for precious metals.
Historically, gold mining accounted for 85 percent of the activity, silver,
for 10 percent and other minerals, such as copper, lead, and zinc, the
remaining 5 percent.
Mining activity in the Central City/Black Hawk area commenced in 1859.
Placer gold was found at the mouth of Chicago Creek, near Idaho Springs, in
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0011283
TABLE 1
DAILY DISCHARGE OF DISSOLVED AND SUSPENDED METALS FROM MINE DRAINAGES
Parameter
(Total)
Mean Discharge
Concentration
Wg/L
Aquatic
Life
AVQCa
Hg/L
Mean Flow
of Discharge
(cfs) (MGD)
Metals
Loading
To Stream
lbs/day
NATIONAL PORTAL
Aluminum
Arsenic
Cadmium
Chromium
Copper
Iron
Lead
Manganese
Nickel
Silver
Zinc
Total
GREGORY INCLINE
Aluminum
Arsenic
Cadmium
Chromium
Copper
Iron
Lead
Manganese
Nickel
Silver
Zinc
Total
243
7
7
6
185
47,475
8
17,625
212
2
6,303
72,073
3,288
5
11
8
879
138,333
20
27,950
192
3
6,315
176,977
150
190j
0.66°
7.2C
6.5€
1.3
88
1.2*
47
150
190
0.66
7.2
6.5
1.3
88
1.2
47
0.06 0.04
0.40 0.26
0.08
0.002
0.002
0.002
0.06
15.8
0.002
5.9
0.07
0.001
2.1
24
7.2
0.01
0.02
0.02
1.9
300.0
0.04
59.4
0.4
0.01
13.7
383
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0011284
TABLE 1 (Cont.)
DAILY DISCHARGE OF DISSOLVED AND SUSPENDED METALS FROM MINE DRAINAGES
Parameter
(Total)
Mean Discharge
Concentration
yg/L
Aquatic
Life
AWQCa
yg/L
Mean Flow
of Discharge
(cfs) (MGD)
Metals
Loading
To Stream
lbs/day
QUARTZ HILL
Aluminum
63,400
150
1.5
Arsenic
1,474
190
0.04
Cadmium
363
0.66
0.009
Chromium
56
7.2
0.001
Copper
48,733
6.5
1.2
Iron
549,667
-
13.3
Lead
137
1.3
0.003
Manganese
62,100
-
1.5
Nickel
480
88
0.01
Silver
18
1.2
0.001
Zinc
89,300
47
2.2
Total
815,728
0.004 0.0029
20
ARGO TUNNEL
Aluminum
19,600
150
49.0
Arsenic
135
190
0.3
Cadmium
126
0.66
0.3
Chromium
19
7.2
0.05
Copper
5,170
6.5
13.0
Iron
144,000
-
360.3
Lead
59
1.3
0.2
Manganese
84,050
-
210.3
Nickel
218
88
0.6
Silver
75
1.2
0.2
Zinc
42,375
47
106.0
Total
295,827
0.46 0.3
740
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0011285
TABLE
1 (Cont.)
DAILY DISCHARGE
OF DISSOLVED AND
SUSPENDED
METALS FROM MINE
DRAINAGES
Aquatic
Mean Flow
Metals
Mean Discharge
Life
of Discharge
Loading
Parameter
Concentration
AWQC3
To Stream
(Total)
Ug/L
pg/L
(cfs) (MGD)
lbs/day
BIG FIVE
Aluminum
14,067
150
3.4
Arsenic
8
190
0.002
Cadmium
27
0.66
0.007
Chromium
14
7.2
0.003
Copper
1,420
6.5
0.3
Iron
51,000
-
12.3
Lead
40
1.3
0.01
Manganese
28,733
-
6.9
Nickel
239
88
0.06
Silver
6
1.2
0.002
Zinc
8,253
47
2.0
Total
103,807
0.045 0.029
25
f AWQC - Ambient Water Quality Criteria (Clean Water Act).
See Fed. Reg. Vol. 51, No. 47, March 11, 1986, p. 8362.
J See Fed. Reg. Vol. 50, No. 145, July 29, 1985.
AWQC for Cadmium, EPA 440/5-84/032, January 1985.
^ AWQC for Copper, EPA 440/5-84-031, January 1985.
AWQC for Lead, EPA 440/5-84/027, January 1985.
? See Fed. Reg. Vol. 45, No. 231, November 28, 1980, p. 79340.
See Fed. Reg. Vol. 51, No. 102, May 28, 1986, p. 19269.
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0011286
TABLE 2
MEAN UPSTREAM WATER QUALITY CONCENTRATION
Clear Creek North Clear
Above Big Five Creek Above
Parameter Units Tunnel Gregory Incline
Aluminum (total)
ug/1
172.60
185.49
Arsenic (total)
ug/1
3.93
3.93
Cadmium (total)
ug/1
4.47
3.42
Chromium (total)
ug/1
5.00
4.75
Copper (total)
ug/1
15.54
17.90
Lead (total)
ug/1
3.68
4.58
Manganese (total)
ug/1
317.34
222.96
Nickel (total)
ug/1
8.45
8.05
Silver (total)
ug/1
.66
.76
Zinc (total)
ug/1
110.71
178.03
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0011287
January of 1859 and in May of the same year, the first lode discovery in
the Rockies was made in Gregory Gulch between Central City and Black Hawk.
Initially, mining was concentrated in the Gregory Gulch area, including the
Gregory Incline. Exploration via adits and shafts rapidly expanded to the
south and west of Central City. The Quartz Hill Tunnel was begun in 1860,
largely for the purpose of transporting ore from the overlying surface
Glory Hole Mine to mills in Central City. The tunnel is over a mile long.
National Tunnel construction was initiated in 1905 and continued to 1937.
The tunnel is believed to be over 3,100 feet in length. The Argo Tunnel
was constructed from 1893 to 1904. The tunnel was built for the dual
purpose of mine drainage and ore transport. The total tunnel length is
4.16 miles, extending from the portal in Idaho Springs in a northward
direction to beneath the headwaters of Gregory Gulch, west of Central City.
In 1982, the Clear Creek/Central City site was ranked as Site No. 174 of
the original National Priority list (NPL) of 400 sites. The site was added
to the NPL in 1983. EPA began a Remedial Investigation (RI) of the site in
June, 1985. During the course of the Remedial Investigation, EPA
determined, in accordance with 40 CFR 300.68(c), that an operable unit
should be conducted to address treatment of mine drainages prior to
discharge to surface waters to assure continued protection of the public
health and environment.
A removal action was initiated by EPA at the Gregory Incline and Tailings
in March 1987 to protect public health and the environment from hazards
associated with the possible collapse of a retaining crib wall that would
have allowed the tailings to slide into North Clear Creek. EPA was
concerned that collapse of the tailings retaining crib would wash a large
load of metals laden tailings downstream into Clear Creek and contaminate
the City of Golden, Colorado municipal water supply. EPA also was
concerned that a collapse could cause short-term flooding in the Black Hawk
area due to North Clear Creek being dammed for a short time. To protect
the public and the environment from these hazards, EPA removed an old
deteriorated crib retaining wall and decreased the slope of the tailings
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0011238
deteriorated crib retaining wall and decreased the slope of the tailings
pile to stabilize it. EPA then constructed a temporary gabion-basket
retaining wall.
Surface water contamination results from low pH mine discharges emanating
from the five tunnels and from seepage of ground water through tailings
piles both proximal to these tunnels and along stream courses. The low pH
mine discharges results in the degradation of water quality and aquatic
habitat. Data gathered during the Remedial Investigation has shown that:
o Runoff from tailings and waste rock piles contains dissolved and
suspended metals.
o There are tailings and waste rock piles adjacent to Clear Creek and
North Clear Creek that are unstable and could collapse into the
creeks. These tailings are acidic in nature. When introduced to
water, the pH will rapidly decrease and significant amounts of
dissolved and suspended metals will be released to the stream.
o Hydrostatic pressure will build up in the tunnels due to cave-ins.
After sufficient pressure has built up, the tunnels will blow out,
releasing large volumes of metals to the creeks.
o Ground water in the vicinity of the tunnels is contaminated.
o There are additional sources of acid mine drainage and tailings
upstream that could be contributing dissolved and suspended metals
to the creeks.
All of the above factors contribute to water quality and aquatic habitat
degradation and will be addressed in the following subsequent operable
units:
Operable Unit No. Two - Tailings and Vaste Rock Remediation
Operable Unit No. Three - Source Control
Operable Unit No. Four - Blowout Control
Operable Unit No. Five - Regional Ground Water Contamintation
Operable Unit No. Six - Upstream Mine Tunnel Discharges and Tailings
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0011289
Current Site Status
The concentrations of most metals (aluminum, cadmium, copper, lead,
manganese, nickel, silver, and zinc) detected in the mine tunnel discharges
exceed Maximum Contaminant Levels (MCLs) established under the Safe
Drinking Water Act (SDWA) for drinking water and Ambient Water Quality
Criteria (AWQC) established under the Clean Water Act for protection of
aquatic life. In several instances, the AWQC for protection of aquatic
life are exceeded in the mine tunnel discharges by more than two orders of
magnitude. Conversely, with respect to the MCLs for drinking water, the
respective dissolved and suspended metal concentrations in Clear Creek and
North Clear Creek are often within the established criteria. It is
important to emphasize, however, that most dissolved and suspended metal
concentrations in the receiving streams exceed AWQC for protection of
aquatic life, which are more stringent than MCLs for drinking water for
these particular contaminants of concern. Table 1 is a computation of the
daily loading of dissolved and suspended metals in the mine discharges from
each of the five mine tunnels in the study and compares mean discharge
concentrations to AWQC.
A public health evaluation was conducted to identify compounds which could
pose a significant health threat. All available data from surface water
and ground water sampling and tailings/waste rock analyses were evaluated.
Results indicate that of the elements detected, there were 10 contaminants
of primary concern due to their widespread extent, potential health and
environmental effects, and relative concentration. The contaminants of
concern were identified as aluminum, arsenic, cadmium, chromium, copper,
fluoride, lead, manganese, nickel, silver, and zinc.
The public health evaluation assessed the following risks associated with
exposure to surface water from ingestion and direct contact by humans and
aquatic life. The results of the public health evaluation follow and are
summarized in Table 3.
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001121)0
TABLE 3
SUMMARY OF RISK ASSESSMENT RESULTS FOR HUMAN EXPOSURE
TO CONTAMINANTS AT THE CLEAR CREEK/CENTRAL CITY SITE
Total Excess Upper-Bound
Lifetime Cancer Risk
Average Maximum Plausible
Exposure Pathway Case Case
Direct contact and incidental
ingestion of water while swimming
& H
*
Clear Creek
5x10 b
2x10
Ingestion of fish
A
Clear Creek
4x10
9x10
North Clear Creek
NE
NE
Ingestion of drinking water
from alluvial wells
O
Clear Creek Subbasin
lxio i
NE
North Clear Creek Subbasin
7x10
NE
NE = not estimated.
It is the Agency's policy that the selected remedy will at least attain a
level of control for such hazardous substances, pollutants, or ^
contaminants that falls within a total risk range of 10" to 10" over a
70-year lifetime exgosure, with a goal of attaining a level of control
that reflects a 10" risk. (See Superfund Public Health Evaluation
Manual.)
k Five additional cancer deaths out of a population of 1 million over a
70-year lifetime exposure.
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0011291
o Concentrations of dissolved and suspended metals in Clear Creek
water, at the intake for the City of Golden water supply, are below
MCLs specified in the Safe Drinking Water Act (SDWA).
o Ingestion of drinking water from ground water wells screened in the
Clear Creek and North Clear Creek alluvial aquifers results in an
upper-bound lifetime cancer risk of 1x10" and 7x10" from exposure
to the geometric mean concentrations of arsenic in the Clear Creek
sub-basin ground water and the North Clear Creek sub-basin ground
water, respectively. Maximum concentrations of arsenic in both
sub-basins exceed MCLs as did the maximum concentrations of cadmium,
chromium, copper, lead, and zinc. The geometric mean concentrations
of cadmium and lead are both above the MCLs. Residents of the
cities of Idaho Springs, Black Hawk, and Central City are on public
water supply systems that meet MCLs.
o Incidental ingestion of arsenic while gwimming incClear Creek may
result in an upper bound risk of 5x10" and 2x10" , under the
average and maximum plausible scenarios, respectively. However, it
should be noted that arsenic concentrations in Clear Creek are
similar to concentrations of arsenic in other Colorado rivers.
o Direct contact with mine discharge water at the Big Five mine and
Argo Tunnel may not irritate hands, but may cause eye irritation.
o Under the maximum plausible scenario, ingestion of fish from Clear
Creek may result in doses greater than the cancer risk criteria for
cadmium, copper, silver, and zinc. Ingestion of fish caught from
North Clear Creek may also result in doses of copper, silver, and
zinc that exceed the cancer^risk criteria. An upper bound lifetime
excess cancer risk of 9x10" was calculated for ingestion in fish
from Clear Creek under the maximum plausible scenario, based on
arsenic. Because arsenic is metabolized in fish to a less toxic
form, the actual risk is probably lower. In addition, as a result
of mine drainage from the five tunnel discharges and other upstream
discharges, neither creek may support enough fish to result in the
assumed intake.
The exposure of aquatic life to acid mine drainage from the tunnel
discharges in the Clear Creek and North Clear Creek drainages, and the
marsh below National Tunnel were also considered. The major conclusions of
this assessment are summarized as follows.
o Several of the chemicals of concern present in Clear Creek, North
Clear Creek, and the marsh below the National Tunnel are at
concentrations that exceed the Federal AWQC established under the
Clean Water Act for the protection of freshwater aquatic life. In
particular, concentrations of zinc, copper, and aluminum
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0011292
consistently exceed the acute and chronic criteria. The pH is lower
than the range of pH's suggested by the EPA for the protection of
freshwater aquatic life. In addition, concentrations of manganese
exceed the lowest observed effect level in rainbow trout. Because
aquatic organisms are exposed to a mixture and not individual
chemicals, toxic effects may be even greater than indicated by
comparison to the criteria. Although some fish may have developed
tolerance to the metals in the creeks, it is highly unlikely that
the population of fish found in these creeks are free of toxic
effects.
EPA conducted a survey of ground water uses in the study area. Samples of
ground water were taken from 13 wells and analyzed for SDVA criteria. Only
one well failed to meet MCLs set under the Safe Drinking Water Act. The
well not meeting SDWA MCLs exceeded cadmium levels. EPA has notified the
owners of the wells of the results of the analyses. A Superfund Removal
Action is planned to replace the contaminated well water.
III. ENFORCEMENT
EPA has determined that the possibility of participation by potentially
responsible parties (PRPs) in the project is minimal. A Potentially
Responsible Party Search was conducted for the Clear Creek/Central City
site but did not result in identifying PRPs for the mine tunnel discharges,
which are the focus of this operable unit. Due to the complexity of the
underground tunnels and lack of historical survey information documenting
tunnel origin and ending, EPA is unable to trace the contamination sources.
The type of investigation that is needed to attempt to determine the origin
of the contaminant source is beyond the scope of a PRP search and would
consist of a land survey and literature, docket and tax record search
conducted to establish which of the mine claims actually cross each of the
tunnels as well as a hydrogeologic analysis of which claims logically drain
into the tunnels. At this time, EPA does not feel that such an
investigation would be fruitful due to the lack of recorded information.
The PRP Search found information on ownership of the mine tailings that
will be used in Operable Unit No. Two. EPA has an extensive list of both
past and present owners of the mine tailings and the underlying property.
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0011293
Because of the inability to identify the origin and therefore allocate
ownership of the mine discharges, EPA does not expect participation in this
operable unit by a financially solvent PRP and for now assumes that the
Hazardous Substances Trust Fund (Superfund) will finance the remedial
action.
IV. COMMUNITY RELATIONS HISTORY
The Community Relations Responsiveness Summary (Appendix A) describes the
community's nature and level of concern regarding the alternatives
evaluated in the feasibility study (FS) for Operable Unit No. One.
After release in June 1987 of the FS Report on Operable Unit No. One, EPA
held two public meetings in conjunction with the public comment period,
June 8 through July 7, 1987. On June 3, 1987 and June 12, 1987,
announcements for the public comment period and public meetings were
published in the newspapers, the Clear Creek Courant and Weekly Register
Call, respectively. EPA distributed the Proposed Plan during the public
meetings. The Proposed Plan was the Executive Summary of the FS Report.
It gave a brief description of the remedial action alternatives and stated
the rationale for the preferred remedy. The Proposed Plan was discussed in
articles in the Clear Creek Courant on June 24 and July 1, 1987.
On June 16 and June 17, 1987, EPA held public meetings on the Proposed
Plan. The preferred remedy stated in the Proposed Plan was construction of
passive treatment systems. In general, the public had mixed reaction to
the passive treatment systems, with some area residents supporting the
concept while others questioned the need for any remediation. The
alternatives selected in the Record of Decision are a logical outgrowth of
the Proposed Plan. Variations from the Proposed Plan will be published
when the Record of Decision is signed. The Responsiveness Summary to this
ROD describes in more detail the nature and level of the community's
concern, and include EPA's responses to all comments received during the
public review of the Operable Unit No. One feasibility study.
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0011294
EPA has established information repositories at the EPA library in Denver,
the Gilpin County Court House in Central City, the Idaho Springs Public
Library and the Idaho Springs City Hall in Idaho Springs, and the Golden
Public Library in Golden, Colorado. The Administrative Record is located
at the Gilpin County Courthouse and the EPA Library. An index of the
Administrative Record is located at each information repository.
V. ALTERNATIVES EVALUATION
The EPA evaluated potential remedial action alternatives to abate the
threat posed by contamination in five mine tunnel discharges primarily by
progressing through the series of analyses which are outlined in the
National Contingency Plan (NCP), in particular, 40 CFR Section 300.68, the
Interim Guidance on Superfund Selection of Remedy, December 24, 1986,
(OSWER Directive No. 9355.0-19) and the Additional Interim Guidance for
FY '87 Records of Decision, July 24, 1987, (OSWER Directive No. 9355.0-21).
This process, in part, enables the EPA to address the SARA Section 121
requirements of selecting a remedial action that is protective of human
health and the environment, that is cost-effective, that attains Federal
and State requirements that are applicable and/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 that EPA give preference to remedies which employ
treatment which permanently and significantly reduces the mobility,
toxicity, or volume of hazardous substances as their principal element.
The selection of remedy process begins by identifying certain site-specific
information to be assessed in determining the types of response actions
that will be considered for the site. A general list of site-specific
information is contained in Section 300.68 (e)(2) of the NCP. This list
was used to identify specific site and waste characteristics of the
Operable Unit No. One of the Clear Creek/Central City site. Based upon
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0011295
these site and waste characteristics, the EPA was able to reduce, from the
universe of many possible response actions, a set of response actions and
associated technologies to be considered for Operable Unit No. One.
Section 121(b)(1) of SARA requires that an assessment 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, mobility, or volume of the hazardous
substance, pollutant, or contaminant be conducted. The alternative
treatment and resource recovery technologies considered included, among
others, passive treatment and metals recovery from sludges.
Before the technologies were evaluated for remedial action alternatives,
they were categorized as either discharge treatment or source control.
Source control measures are intended to contain the mine discharges within
the five tunnels.
The next step of the selection of remedy process is assembling the
technologies and/or disposal options into remedial action alternatives.
Pursuant to OSVER Directive No. 9355.0-19, "Interim Guidance on Superfund
Selection of Remedy", remedial action alternatives were considered ranging
from those that would eliminate the need for long-term management
(including monitoring) at the site to alternatives involving treatment that
would reduce mobility, toxicity, or volume as their principal element.
Remedial action alternatives developed in this way will vary mainly in the
degree to which they rely on long-term site management. Further, a
containment option involving little or no treatment and a no action
alternative were developed as required by Section 300.68(f)(l)(v) of the
NCP.
The remedial action alternatives developed in the FS for Operable Unit No.
One for the Clear Creek/Central City site are:
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No Action
0011206
Active Treatment
o Lime Precipitation
o NaOH (Caustic) Precipitation
o Reverse Osmosis
o Electrodialysis
o Ion Exchange
o Freezing
o Iron Oxidation/Precipitation
o Sulfide Precipitation
o Distillation
o Recycling Bacterial Waste
o Coagulation/Flotation
o Evaporation
o Deep Well Injection
o Electrochemical Precipitation
Passive Treatment
Source Control
o Dry/Air Seals
o Fracture Zone Seals
o Portal Bulkheads
Controlled Release
Alternatives were subjected to an initial screening to narrow the list of
potential remedial actions for further detailed analyses using the criteria
of cost, effectiveness, and implementability (acceptable engineering
practices) as directed by 40 CFR Section 300.68(g) and the ability to
reduce the toxicity, mobility, or volume of contaminants, as directed by
SARA. Costs, including Operation and Maintenance (0&M) were considered for
each alternative. Each alternative was screened by evaluating engineering
feasibility, applicability, and reliability. Effectiveness in protecting
human health and the environment was considered. During the initial
screening process, the controlled release alternative and the following
discharge treatment alternatives were eliminated: reverse osmosis,
electrodialysis, ion exchange, freezing, distillation, recycling bacterial
waste, evaporation, and deep well injection. The Source Control
alternative was recommended for further study, including field
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001121)7
investigations, under Operable Unit No. Three. The remaining alternatives
were further considered in the section on Detailed Analysis of Remedial
Action Alternatives.
The justification for elimination of these alternatives follows.
Reverse Osmosis: This alternative was eliminated for the treatment of mine
tunnel discharges from Clear Creek/Central City study area for the
following reasons:
o The majority of dissolved iron in the Argo, Big Five, and National
discharges are in the ferric form. Maintenance costs in providing
an adequate product flow rate are expected to be extreme due to
membrane fouling.
o Sulfate concentrations in the mine tunnel discharges are expected to
result in significant operational problems from the formation of
calcium sulfates on the membranes.
o Additional treatment or disposal facilities will have to be
constructed to provide for disposal of the brine, estimated to be up
to 25 percent of the influent.
Electrodialysis: Electrodialysis has demonstrated only marginal dissolved
solids removal. The most efficient removal occurs at high temperatures
with a 1 percent removal per degree fahrenheit increase in temperature.
Increases in temperature compound the problem of scaling on the membranes.
Power consumption estimates are 0.2 to 0.4 kwH per 100 mg/L dissolved
solids per 1,000 gallons treated plus an additional 3 to 3.5 kwH/1,000
gallons treated for pumping and brine handling. Power cost estimates,
based on 3,000 mg/L of dissolved solids and $0.06/kwH translate into
$0.09/1,000 gallons. Brine volumes will be in the range of 15 to 25
percent of the influent flow and will require additional treatment by
neutralization and precipitation and sludge disposal. Electrodialysis will
not be considered further because the technology is only marginally
feasible and is not cost-effective for this application.
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0011298
Ion Exchange: This alternative was eliminated as the primary treatment
process for the treatment of mine tunnel discharges for the following
reasons:
o The ion exchange process generates a waste stream that may be as
high as 25 percent of daily influent treated. Ancillary treatment
facilities for these waste present significant additional costs.
o Although the success of the modified DeSal and Two Resin Processes
in removing the reduced form of soluble metal species has been
demonstrated, discharges from the Argo Tunnel contain significant
ferric iron which is expected to clog the weak base resins requiring
extensive regeneration and eventually rendering them ineffective as
a form of treatment.
o Cost comparison on a dollar/1,000 gallons treated basis shows that
cost ranges for ion exchange ($1.00-$7.00/1,000 gallons, 1977
dollars) exceeds that of conventional neutralization/precipitation/
clarification ($0.20-$l.30/1,000 gallons, 1977 dollars) without
realizing significant additional benefits in metals reduction.
o Both the Modified DeSal and Two Resin processes require treatment of
column effluents for the precipitation and removal of metals.
Additional treatment of waste backwashes is also required. Both
treatment processes will generate sludges that require dewatering
and disposal.
Ion exchange will be considered as a tertiary treatment process to remove
trace metals.
Freezing: This technology is considered technically unfeasible. A
literature review shows that freezing has been effective and economical in
recovering cadmium and hexavalent chromium. However, initial concentra-
tions were 100 mg/L. Freezing has not been shown to be technically
feasible or cost-effective for removing other heavy metals, especially on a
large scale.
Distillation: Operating costs are significantly higher than reverse
osmosis, electrodialysis, or ion exchange. Because of attendant high
operating costs, this alternative was excluded from further analysis.
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0 01121> 9
Recycling Bacterial Waste; This technology would not be technically
applicable for the Clear Creek/Central City study area because:
o Mine tunnel discharge and inhibitors would have to be injected at
all surface recharge points. This is not technically feasible
considering the length of main tunnels and connecting tunnels.
o Mine tunnel discharges would have to be continuously recycled to
upstream surface recharge points until bacterial growth was
inhibited.
Evaporation: This technology would not be technically applicable to this
site because:
o There is insufficient land area for construction of a reservoir,
except for Quartz Hill.
o Depth to water table is minimal and reservoir sites would be in the
floodplain.
Deep Veil Injection: This alternative, although technically feasible,
requires significant geological and geophysical subsurface investigative
work and literature review in order to determine a suitable injection
location for disposal of acid mine drainage. Deep well injection may lead
to aquifer contamination and does not result in reduction in the mobility,
volume, or toxicity of contaminants. Even after a suitable site has been
identified, costs for permitting, injection well installation, and
operation and maintenance are expected to be extreme. (With implementation
of land disposal restrictions, under RCRA, the discharge may have to be
treated prior to injection. Moreover, long-term viability of an operating
injection well is constantly in question because for the potential of
formation rejection of injected volumes or plugging of the well.
This alternative will not be analyzed further because it does not reduce
toxicity, mobility, and volume of contaminants and because of the expected
high costs and uncertainty involved with using this technology.
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00113
Controlled Release: Controlled release requires water to be stored for
release to streams during high flow periods to take advantage of dilution.
This alternative would not be technically applicable because:
o There is insufficient land area for construction of a reservoir,
except for Quartz Hill.
o Depth to water table is minimal and reservoir sites would be in the
floodplain.
o Dissolved and suspended metals would precipitate with suspended
charge and releated particles into bottom sediments. Resuspension
would still be possible.
Source Control Alternatives: A literature search and review of available
mine maps was conducted in order to investigate the feasibility of various
alternatives for source and discharge control of mine discharges from the
five tunnels. Available information on the hydrology in the Clear
Creek/Central City area indicates the following:
o The source of discharge from the tunnels is from percolating ground
water that directly enters the mines through fractures, intersecting
veins or intersecting tunnels, shafts, or cross cuts. The water in
intersecting tunnels is also due mainly to ground water inflow.
o Although some of the mine discharge may be related to runoff, the
majority of flow is due to ground water inflow. This is shown by
the relatively constant discharge from the mines. If the discharge
was mostly influenced by runoff, we would expect the discharge to
show a more pronounced seasonal fluctuation.
o The source or recharge area for the ground water is mainly
infiltration over a large area.
o The water infiltrates mainly through fractures and veins and
accumulates in the drainage tunnels. Little of the source is due to
point source contributions (such as the intersection of the adits
with surface channels).
Given this current state of information, no accurate predictions could be
made concerning the feasibility of source control. Therefore, further
investigations including field work will be conducted under Operable Unit
No. Three.
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001130
DETAILED ANALYSIS OF REMEDIAL ACTION ALTERNATIVES
Consistent with Section 300.68(h) of the NCP, the Office of Solid Waste and
Emergency Response (OSWER) Directive No. 9355.0-19, and the OSWER Directive
No. 9355.0-21, the remedial action alternatives remaining after initial
screening were further refined and then subject to detailed analysis.
Detailed analysis of each remedial action alternative entailed evaluation
based on the criteria derived from the NCP and SARA. These criteria relate
directly to factors mandated by SARA in Section 121, including Section
121(b)(l)(A-G). The criteria are as follows:
o Protection of human health and the environment
o Compliance with legally applicable and/or relevant and appropriate
requirements
o Reduction of mobility, toxicity, or volume
o Short-term effectiveness
o Long-term effectiveness and permanence
o Implementability
o Cost
o Community acceptance
o State acceptance
The evaluation of alternatives reflects the mandate to utilize permanent
solutions and alternative treatment technologies to the maximum extent
practicable, as specified in Section 121 of SARA. The alternatives
selected for further analyses included:
o No Action
o Passive Treatment
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0011302
o Active Treatment
o A combination of Passive Treatment and Active Treatment
The alternatives are described in the following paragraphs, followed by a
comparative matrix evaluation, using the above evaluation criteria.
Description of Alternatives
No Action Alternative: The No Action alternative assumes that there will
be no treatment of mine tunnel discharge and that approximately 1,200
pounds per day of aluminum, arsenic, cadmium, chromium, copper, iron, lead,
manganese, nickel, silver, and zinc will continue to be discharged into
Clear Creek and North Clear Creek. Remedial measures would be constructed
to limit the public's exposure to the acid mine drainage, i.e., fencing,
piping, etc.
Passive Treatment Alternative: Passive treatment is an innovative
treatment technology that involves creation of an artificial wetland to
emulate or enhance natural metal ion removal and acidity reduction
processes. Passive treatment was evaluated for the five tunnel discharges
based upon available area requirements, the ability of passive treatment to
significantly reduce the volume, mobility, or toxicity of contaminants, and
its ability to eliminate the need for long-term management. A passive
treatment pilot plant has been constructed at the Big Five Tunnel to
evaluate the effectiveness of wetlands in removing metals from acid mine
drainage. Based upon the results of the pilot plant studies, passive
treatment systems would be built to treat all five tunnel discharges.
There is sufficient land area near each tunnel to install passive treatment
systems.
Observations have shown that concentrations of metals present in acid mine
tunnel discharges are reduced as the water flows through natural bogs and
wetlands. These observations led to the concept that these natural systems
could be designed and constructed to provide a self-sustaining treatment
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0011303
that would be inexpensive and require minimal maintenance for long-term
operation. These "passive" treatment techniques rely upon emulating or
enhancing the process of metal ion removal and reduction of acidity. In
order to design the natural wetland situation, the concept was expanded to
include augmenting or replacing the peat with other organic materials to
provide a growth medium, and then transplanting several appropriate species
of native vegetation to enhance the continual addition of organic matter to
the growth medium.
Investigations of inexpensive, low-maintenance alternative treatment
systems have been and are currently being conducted in Colorado and
elsewhere. These alternative systems rely upon natural processes including
filtration, cation exchange, sorption, coprecipitation, complexation, and
biologic extraction to remove metal ions, and aeration or the addition of
limestone as a buffer to stabilize the pH. Since the investigation into
the heavy metal removal processes is a relatively new field of study, the
removal mechanisms, the relationships among the process, and their relative
importance are not thoroughly understood.
Studies by the Colorado Mine Land Reclamation Board, U.S. Bureau of Mines,
and various universities are currently exploring continual
dissolved/suspended metal extraction using systems that consist of two
basic phases. The first phase removes metals, primarily iron, by employing
the natural processes that occur in self-perpetuating, artificially created
peat bogs. In the second phase, cascades are used to exsolve carbon
dioxide, and coarse limestone rock is added to the effluent discharge
channel to reduce acidity. Results of these studies have aided in the
development of preliminary design concepts for low maintenance, passive
treatment systems.
Cation exchange processes in peat and Sphagnum moss (humus) are believed to
be responsible for the metal ion removal. The cation exchange properties
of peat and peat-forming plants are attributed to the carboxyl functional
groups found in the humic acids of peats and the pectic compounds in plant
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001130
cellular tissue. Pectic compounds are polymers composed primarily of
galacturonic acid. They are found in greatest abundance in the middle
lamella between the plant tissue cell walls.
Annual vegetation and decaying plants generally remain standing for a
period of time until snow, wind, or other phenomena cause them to collapse.
These collapsed materials contribute to the formation of peat and decompose
slowly under anaerobic or low pH conditions. Metals accumulated in
decaying leaves and stems may be retained in the substrate in the formation
of new peat, thus the plants may perform an important metal uptake removal
function in the wetland. Partially decomposed plants have also been shown
to remove metal ions from solution.
Passive treatment sites require placement of a liner before placement of
organic material. The liner will be required to prevent ground water
contamination. To stay within the intent of RCRA, groundwater monitoring
may be necessary.
Active Treatment Alternatives: Alkaline precipitation (by using lime,
sodium hydroxide, or sulfide) was evaluated and identified as an
alternative that would meet upstream water quality concentrations in a
treatment plant discharge line. Laboratory treatability studies of
precipitation technologies were conducted. Lime precipitation was selected
as the preferred technology. Electrochemical precipitation is an
innovative process that may play a role in active treatment. However,
additional investigation will be necessary to determine the applicability
of electrochemical treatment.
Passive Treatment and Active Treatment Combination Alternative: A
combination of passive and active treatment systems would be constructed to
treat mine tunnel discharge. The purpose of combining the two treatment
systems is to reduce the volume of lime required to precipitate metal
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0011305
hydroxides and thereby also reduce the volume of sludges that occur in an
active treatment facility. The reduction in sludge volume is estimated to
be 45 percent.
Comparison of Alternatives
Listed in Table 4, in matrix format, are the key criteria considered in
evaluating and comparing alternatives. These are specified in J. Winston
Porter's memorandum "Additional Interim Guidance for FY '87 Records of
Decision," dated July 21, 1987. The cost summary of alternatives is
compared in Table 5.
VI. SELECTED REMEDY
Description of Selected Remedy
The selected remedy for Operable Unit No. One of the Clear Creek/Central
City site consists of construction of passive treatment systems to treat
mine tunnel discharges prior to discharge to surface waters. This is the
preferred alternative and is contingent upon the results of on-going pilot
plant studies demonstrating that upstream water quality concentrations can
be achieved by a passive treatment system. If the upstream water quality
concentrations cannot be achieved by passive treatment, then either of the
following treatment systems will be built:
o a combination system consisting of passive and active treatment will
be constructed. A phased approach to construction will be utilized.
o two active treatment systems (chemical precipitation or
electrochemical precipitation) will be constructed to treat mine
tunnel discharges prior to discharge to surface waters.
The selected remedy for treating mine tunnel discharges is cost-effective
and is protective of human health and the environment. A pilot treatment
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TABLE 4
-Cr-AKISON OF ALTERNATIVES
No Action
Passive Treatment
1. Coapliance with ARARs Does not meet ARARs
Di* ability to wet upstream levels and
ARARs will be evaluated in a pilot
plant. ARARs for disposal of metal
laden organic Material, including land
disposal restrictions, will be coaplied
with. Fixation technologies will be
used to ensure that the material passes
the CP toxicity test and the treated
material will be disposed in a municipal
landfill.
2. Reduction of Mobility,
. Toxicity, and Volume
I
to
V
3. Short-Tena
Effectiveness
Does not reduce mobility, toxicity, or
volume of contaminants.
Does not reduce risk to aquatic life.
Fencing will reduce dermal exposure to
public.
the organic material in the wetland will
remove significant quantities of heavy
metals, thereby reducing mobility,
of metals in the tunnel discharge.
Heavy metals will build up in the
organic material. The buildup will be
monitored yearly and the organic
material removed and disposed when
necessary (estimated at every 5 to 10
years). Fixation or similar technology
would be used to reduce mobility and
toxicity.
Risk to aquatic life will be reduced by
reducing metal loading to creeks.
Vegetation should acclimate after one
growing season. Yearly maintenance may
be required to reestablish vegetation.
4. Long-Term
Effectiveness
No reduction in exposure of human and
environmental receptors to metal9 in
discharges.
A pilot plant study will assess the
amount of buildup of metals in the
organic material in order to estimate
how often the organic material will have
to be replaced.
Active Treatment
Passive and Active
Treatment Combination
Treatability studies have shown that
active treatment will remove 99.9
percent of metal ions and meet upstream
levels and will not meet all
contaminant-specific ARARs.
Approximately 1,430 cubic yards of
sludge would be produced each year. The
sludge passes the EP toxicity test.
Sludge disposal will meet ARARs for
landfill disposal and any new subtitle D
ARARs.
A combination of passive treatment and
active treatment will meet upstream
levels and will not meet all
contaminant-specific ARARs.
Approximately 1,430 cubic yards of
sludge would be produced each year. Hie
sludge passes the EP toxicity test.
Sludge disposal will meet ARARs for
landfill disposal and any new Subtitle D
ARARs.
Laboratory treatability studies showed
that metal concentrations in the
discharge would be reduced by 99.9%.
The metals would be concentrated in a
lime sludge that would be dewatered and
disposed in a landfill. The dewatered
sludge passes EP toxicity tests.
Passive treatment will reduce the volume
of metal hydroxide sludges produced in
the lime precipitation facility by an
estimated 45 percent. Laboratory
treatability studies showed that metal
concentrations in the discharge would be
reduced by 99.9 percent. Hie metals
would be concentrated in a sludge that
would be dewatered and disposed in a
landfill. The dewatered sludge passes
EP toxicity tests.
Construction of a precipitation plant
will be immediately effective in
protecting the environment.
Both Passive Treatment and Active
Treatment comments apply.
If properly maintained, construction of
a precipitation treatment plant will
protect the environment over the long
term.
Both Passive Treatment and Active
Treatment comments apply
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TABLE 4 (cont.)
COMPARISON OP ALTERNATIVES
Ho Action Passive Treatment
5. Implementability
Fences are easily constructed but mist
be Maintained to prevent human contact,
upon fence deterioration.
The existing pond at the Big Five Tunnel
will have to be drained and filled.
Passive treatment is isplementable once
the pilot plant studies are completed in
September 1988. Design and construction
will take up to 8 months.
Capital costs for construction of
fencing, inlet boxes, and piping is
estimated to be $33,700. The fencing
would have to be replaced every 20 to 30
years.
Construction involves the use of readily
available construction equipment.
Capital costs are estimated at
$1,663,000. This estimate includes
$347,000 for gravity pipelines which lay
be reduced based on siting studies.
Yearly operation and maintenance costs
(0(H) are estimated to be $115,000. Ret
present worth of capital and otM costs
at a 10 percent interest rate was
calculated to be $2,747,000.
7. Community Acceptance
1
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8. State Acceptance
Many residents of Idaho Springs, Central
City, and Black Hawk support the No
tetion alternative because they have
been living with mine drainage all their
lives. Downstream users and fishing
groups do not support the No Action
alternative because of water quality and
aquatic habitat degradation.
The Colorado Department of Health does
not support the No Action alternative.
The Colorado Department of Wildlife
estimates the economic value of the
Fishery Resource potential as $736,000
per year.
The majority of people favor passive
treatment as a low-cost, low maintenance
treatment alternative.
See Responsiveness SuaMry.
The Colorado Department of Health and
Colorado Hined Land Reclamation Board
are in favor of passive treatment as a
low-cost treatment alternative.
Active Treatment
Passive and Active
Treatment Combination
The equipment required for this
technology is readily available and is
used in municipal sewage treatment
plants. Construction will take up to 18
months.
Construction involves the use of readily
available construction equipment.
The passive treatment system will be
constructed and operated prior to
construction of the active treatment
system.
Construction involves the use of readily
available construction equipment.
The capital cost for construction of a
North Clear Creek and Clear Creek
treatment plant is estimated to be
$2,275,000. Annual operation and
maintenance costs for the two plants ace
estimated to be $548,600. ftie present
value of capital and OUt costs based on
a 10% interest rate are $7,732,000.
The capital cost for construction of a
North Clear Creek and Clear Creek
facility is estimated to be $3,864,000.
Annual OtM costs for the two facilities
ace estimated to be $511,200. The
present value costs at a 10% interest
rate are estimated to be $8,967,000.
The community would like to know who is
responsible for long-term facility
operation.
The coamunity would like to know who is
responsible for the long-term facility
operation.
Responsiveness Su
ary.
See Responsiveness Suamary.
The State is concerned about the long-
term operation and maintenance costs for
running the facility.
The State is concerned about the long-
term operation and maintenance costs for
cunning the facility.
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TABLE 4 (cont.)
COMPAPIoON OF ALTERNATIVES
No Action
Passive Treatment
Active Treataent
Passive and Active
Treataent Coabination
9. Overall Protection of
Human Health and the
Environment
Impacts on human health due to the
surface water pathway are minimal due to
dilution of metal concentration by the
flow in clear Creek. The no action
alternative is not protective of the
environment. If fences are not
maintained, it is not protective of
human health because of exposure to low
pH aine tunnel discharge.
Passive treataent significantly improves
protection of human health and the
environment. Pilot plant studies will
determine the extent of protection of
the environaent.
Active treatment significantly iaprovet
protection of human health and the
environment.
The coabination alternative
significantly iaproves protection of
human health and the environment.
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TABLE 5
COST SUMMARY
0011309
Alternative
Cost Estimates
($1,000)
Capital Annual O&M
Present Worth at
Discount Rate ($1,000)
10%
1. No Action 33
2. Passive Treatment 1,663
3. Active Treatment 2,275
4. Passive Treatment and 3,864
Active Treatment
Combination
115
549
511
2,549
7,732
8,967
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00113
plant has been constructed at the Big Five Tunnel in order to gather design
data and determine the extent of treatment attainable from passive
treatment systems.
Target treatment levels for the interim remedy in the treatment system
discharge pipe are upstream water quality concentrations. These are more
stringent than Colorado Effluent Limitations (Table 6).
Disposal of Metal Laden Organic Material From Passive Treatment Systems
The material processes of senescence and death of vegetation will provide
additional organic matter (humus) annually to remove metals from the
discharge. This organic replenishment is estimated to be sufficient to
increase metals uptake capacity so that removal and replacement of the
organic matter in the treatment systems is planned (and included in the
costs) every seven years. The organic matter will contain metals that were
removed from the mine tunnel discharges. For disposal considerations, the
metals of concern are arsenic, cadmium, chromium, lead, and silver. The
accumulation of these metals could result in a material that may be a
characteristic waste under RCRA due to metals which exceed the EP toxicity
levels. In order to determine if the materials are EP toxic, the materials
from the pilot plant will be evaluated using both the EP (extract
procedure) toxicity test and the TCLP (toxicity characteristic leaching
procedure) tests. If the leeichate concentrations exceed standards,
treatment with appropriate fixation agents will be performed prior to
disposal in a municipal landfill. Because the materials are characteristic
wastes, the metals will be made non-hazardous by reducing the leachability
of the metals below EP and TCLP levels. This reduction is achievable by
using various agents (cement, kiln dust, fly ash, etc.) which fix the
metals in a less leachable form.
Current knowledge indicates that passive treatment systems have two removal
zones. An aerobic zone removes metal oxyhydroxides and an anaerobic zone
removes metals in the sulfide form. The aerobic zone may only be 1 to 3
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TABLE 6
METAL REMOVAL ESTIMATE
Expected
Passive
Discharge Water
Expected
Treatment
Quality After
Discharge Water
Colorado
Upstream Water
Mean Discharge
Removal
Passive
Quality After
Effluent
Quality Concentrations
Water Quality
Efficiency
Treatment
Active Treatment
Limitations
(»g/L)
Metal
rng/L (Total)
<%)
(mg/L)
(mg/L)
(aq/L)a
North Clear Creek
NATIONAL
Aluminum
0.2
90
0.02
0.02
_
0.19
Arsenic
0.007
Unknown
¦3
<0.005
-
0.004
Cadmium
0.007
95
<0.001
<0.001
0.1/0.05
0.004
Copper
0.2
95
<0.01
0.003
0.3/0.15
0.018
Iron
47.5
75
12
<0.05
-
*
Lead
0.008
95
<0.001
<0.001
0.6/0.3
0.005
Manganese
17.6
50
9
0.01
-
0.23
Nickel
0.2
95
<0.01
<0.01
-
0.008
Zinc
6.3
95
<0.3
<0.001
1.5/0.75
0.18
QUARTZ HILL
Aluminum
63.0
90
6.3
<0.001
_
0.19
Arsenic
1.5
Unknown
7
<0.001
-
0.004
Cadmium
0.4
80
0.8
<0.001
0.1/0.05
0.004
Copper
48.7
80
10
<0.001
0.3/0.15
0.018
Iron
550.0
90
55
<0.001
-
*
Lead
0.1
80
0.02
<0.001
0.6/0.3
0.005
Manganese
62.0
50
31
<0.001
-
0.23
Nickel
0.5
80
0.1
<0.001
-
0.008
Zinc
89.0
80
18
<0.001
1.5/0.75
0.18
GREGORY INCLINE
Aluminum
3.3
90
0.33
<0.001
_
0.19
Arsenic
0.005
Unknown
7
<0.001
-
0.004
Cadmium
0.011
80
<0.002
<0.001
0.1/0.05
0.004
Copper
0.9
80
0.18
<0.001
0.3/0.15
0.018
Iron
138
90
14
<0.001
-
*
Lead
0.02
80
0.004
<0.001
0.6/0.3
0.005
Manganese
28
50
14
<0.001
-
0.23
Nickel
0.2
80
0.04
<0.001
-
0.008
Zinc
6.3
80
1.26
<0.001
1.5/0.75
0.18
-------
TABLE 6
METAL REMOVAL ESTIMATE
Metal
Mean Discharge
Water Quality
mg/L (Total)
Passive
Treatment
Removal
Efficiency
<%)
Expected
Discharge Water
Quality After
Passive
Treatment
(mg/L)
Expected
Discharge Water
Quality After
Active Treatment
(mg/L)
Colorado
Effluent
Limitations
(mg/L)a
Upstream water
Quality Concentrations
(mg/L)
Clear Creek
ARfiO
Aluminum
Arsenic
Cadmium
Copper
Iron
Lead
Manganese
Nickel
Zinc
BIG FIVE
Aluminum
Arsenic
Cadmium
Copper
Iron
Lead
Manganese
Nickel
Zinc
19.6
0.135
0.126
5.2
144.0
0.059
84.0
0.218
42.0
14.0
0.008
0.027
1.4
51.0
0.04
29.0
0.239
8.3
80
Unknown
80
80
80
80
80
80
80
80
Unknown
80
80
80
80
80
80
80
<2
•y
<0.025
<1
14
<0.01
42
8
8
1.4
->
<0.005
0.28
5
0.008
15
<0.05
1.7
0.4
<0.005
<0.001
0.003
<0.05
<0.001
0.01
<0.01
<0.001
0.02
<0.005
<0.001
0.003
<0.05
<0.001
0.01
<0.01
<0.001
0.1/0.05
0.3/0.15
0.6/0.3
1.5/0.75
0.1/0.05
0.3/0.15
0.6/0.3
1.5/0.75
0.17
0.004
0.005
0.016
*
0.004
0.32
0.008
0.11
0.17
0.004
0.005
0.016
*
0.004
0.32
0.008
0.11
Source: CSM, 1987
a) One day maximum; 30 days average, respectively.
* Not a contaminant of concern.
-------
0011313
inches deep and the anaerobic zone may be up to 3 feet deep. Sulfides in
the anaerobic zone will not resolubilize. As vegetation dies and decays
and the wetlands increase in volume, metal ions may change from the
hydroxide to the sulfide form. If this process does occur, then periodic
removal of metal laden organic material from the passive treatment systems
may not be required.
The passive treatment pilot plant that has been constructed at the Big Five
Tunnel will be used to study the cation exchange process and to determine
the depth of the aerobic and anaerobic zones. The results of the pilot
plant investigation will determine the depth and frequency of removal of
metal laden organic material from the passive treatment systems.
As part of the cost estimate, removal and fixation of the organic material
has been assumed to occur every seven years. Because the materials are
non-hazardous, the materials can be disposed in municipal landfills.
However, as an added precaution, disposal costs were estimated for
containment in lined cells within a fly ash disposal area. A site in
Denver, is currently approved by the State of Colorado for disposal of
metal fixed wastes.
The disposal estimate is based on removal and fixation of 6,500 cubic yards
of material every seven years at $50 per cubic yard. This assumes that the
upper 1 foot of material will be removed from 175,000 square feet of
passive treatment systems and replaced with clean organic material at $10
per cubic yard (1987 dollars).
Disposal of Lime Treated Sludge from Active Treatment Plants
Treatability studies of mine tunnel discharges showed that lime treated
metal hydroxide sludges pass both the EP and TCLP tests and can be disposed
in municipal landfills.
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0011314
Effects of Passive Treatment System Construction 011 Wildlife
Construction of passive treatment systems will result in creation of food
and cover sources for terrestrial and aquatic wildlife. Use of these areas
will be dependent upon the extent of open water habitat created and the
proximity of these areas to other suitable habitats which could attract
wildlife, thereby enhancing the potential for use of passive treatment
areas. Waterfowl (particularly species of Anatid ducks, which are
residents of the area), songbirds which require wetland, or riparian areas
as breeding habitat, and herbivorous vertebrates are among the species most
likely to be affected by wetland construction. Creation of wetland
habitats 1,200 to 80,000 square feet in extent will not have a significant
regional effect on habitat carrying capacity or on population levels of
wildlife. Local concentrations of some species can be expected to occur
where wetlands are created in close proximity to riverine, riparian, or
wetland areas which currently receive use.
Although the potential exists for bioconcentration of some metals in
wetland plants which may be used as wildlife forage, bioconcentration and
subsequent bioaccumulation of metals in vertebrate and invertebrate
wildlife will be dependent upon a variety of site-specific physical,
chemical, and ecological factors. These factors may include: the form or
chemical species of metals present; the amount of contaminants present (and
variation of these amounts throughout wetland areas and over time); the
availability of pollutants to organisms capable of uptake; and the
ecological significance of passive treatment areas as sources of food for
any organism, considering the proportion of its home range which any
treatment area represents. In general, the biological significance of
metallic contaminants in wildlife food chains at these passive treatment
sites is expected to be negligible due to adsorption and complexation
processes within detrital materials or sediments which are expected to
limit bioconcentration in forage and invertebrate prey organisms. In
-35-
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0011315
addition, wildlife access to these sites will be controlled by fencing to
limit exposure. Where feasible, strobe lights will be installed to limit
wildfowl access.
Capital and Operation and Maintenance Costs (O&M)
Estimated capital costs, O&M costs, and present worth costs are listed in
Table 5.
Schedule
The following schedule is planned for this project:
Approve Remedial Action (sign ROD)
Initiate Design
Complete Design
Initiate Construction
Statutory Determinations
Protectiveness: The Public Health Evaluation showed that there is no
immediate danger to public health from mine tunnel discharge at present
flow rates because of dilution from flows in Clear Creek. Also, the cities
of Idaho Springs, Blackhawk and Central City have municipal water supply
systems that meet MCLs. However, mine tunnel discharges have severely
impacted water quality for aquatic life and aquatic habitat has been
destroyed. Construction of treatment systems will improve water quality
and enhance aquatic life.
Consistency With Other Environmental Requirements: Section 121(d)(1) of
SARA requires that selected remedial actions attain a degree of cleanup of
hazardous substances released into the environment and control of further
release at a minimum which assures protection of human health and the
environment. Section 121(d)(2) of SARA states that remedial actions shall
require a level or standard of control which at least attains legally
September, 1987
November, 1987
June, 1989
July, 1989
-36-
-------
0011316
applicable and/or relevant and appropriate standards, limitations,
criteria, and requirements of Federal environmental laws, and applicable
and/or relevant and appropriate promulgated requirements under State
environmental or siting laws that are more stringent than Federal
requirements. The ARARs analysis is included in Appendix B.
The Feasibility Study for this operable unit identified a range of
potential ARARs, including MCLs, and AWQC established under the Clean Water
Act. After consideration of public comments, the Agency has determined
that the contaminant specific applicable and/or relevant and appropriate
requirements for this operable unit are the Maximum Contaminant Levels
(MCLs) established under the Safe Drinking Water Act (SDWA) for hazardous
substances, pollutants, or contaminants identified in mine discharge in the
Clear Creek/Central City Site, Ambient Water Quality Criteria (AWQCs)
established under the Clean Water Act for protection of aquatic life and
human health, and State Contaminant-Specific ARARs.
The interim remedy will meet upstream water quality concentrations for
treating mine tunnel discharges. The remedy is an interim solution for the
overall Clear Creek/Central City site requiring the exercise of the
"interim remedy" waiver from contaminant-specific ARARs (Section 121(d)(4)
of SARA). The upstream water quality concentrations will be used as
operational standards for this interim remedy. The upstream water quality
concentrations ("upstream levels") consist of the geometric mean of the
subset of RI samples taken on Clear Creek immediately upstream of the
discharge from the Big Five Tunnel and on North Clear Creek immediately
upstream of the discharge from the Gregory Incline. These upstream levels
are not to be considered as final applicable and/or relevant and
appropriate requirements for the final site remedy. Cleanup of Clear Creek
and North Clear Creek to meet contaminant specific ARARs is dependent on
further remedial action to be undertaken in future operable units. Future
operable units are expected to be completed within 18 months, at which time
a final solution will be proposed. The interim remedy is consistent with
the final site remedy.
-37-
-------
0011317
In accordance with SARA section 121(d)(2)(A(ii), EPA intends that the final
remedy will at least attain water quality criteria established under the
Clean Water Act, where such criteria are relevant and appropriate under the
circumstances of the release. Additional data collection and analysis are
necessary for EPA to determine whether such national criteria are relevant
and appropriate under the circumstances of these releases or whether
site-specific modification to national criteria would more appropriately
establish a clean-up goal for this site. EPA needs to consider such
circumstances as ambient background levels, stream habitat, upstream
contaminant contributions and non-point source contributions in making a
determination. This interim remedy will provide substantial protection of
human health and the environment, while providing the time necessary for
EPA to make this determination. Until such time that it is determined that
site specific modification to individual contaminant criteria are
necessary, EPA will consider the more stringent of human health or aquatic
life ambient water quality criteria (AWQCs) as an ARAR for the final
remedy.
Location specific and action specific ARARs will be met. Land disposal
criteria established under 40 CFR Section 268 are applicable for disposal
of metal laden organic material. New requirements established for mining
wastes under Subtitle D of RCRA will be applicable. Also, portions of the
site are within Historical Districts and criteria established under the
National Historic Preservation Act are applicable (36 CFR Section 800).
The State of Colorado provided EPA with a list of applicable and/or
relevant and appropriate State standards, requirements, limitations, or
criteria ("State requirements") for this operable unit on May 14, 1987.
The State amended its list on July 27, 1987 to add two additional
requirements. EPA has reviewed the proposed State requirements under the
criteria set forth in Section 121(d) of CERCLA, and determined that certain
provisions within the State requirements generally are applicable or
relevant and appropriate (see Appendix B).
-38-
-------
00113
Cost Effectiveness and Utilization of Permanent Solutions and Alternative
Treatment Technologies to the Maximum Extent Possibles The principal
threats posed by mine tunnel discharges are metals contamination of surface
water, ground water, and sediments. Passive treatment is an innovative
technology that is expected to reduce dissolved and suspended metal loading
by at least 50 to 90 percent in the discharge, depending on the metal. If
passive treatment does not meet upstream water quality concentrations, then
either active treatment or a combination of active treatment and passive
treatment will be implemented.
The installation of either of these treatment systems meets the statutory
preference for permanent solutions that reduce the mobility, toxicity, or
volume of metals in the discharge.
-39-
-------
APPENDIX A
frfrtTgl9
ADMINISTRATIVE RECORD
SF FILE NUMBER
RESPONSIVENESS SUMMARY £, |
OPERABLE UNIT NO. 1 OF THE
CLEAR CREEK/CENTRAL CIT5T SITE
CLEAR CREEK AND GILPIN COUNTIES, COLORADO
SEPTEMBER 1987
This community relations Responsiveness Summary for Operable Unit No. 1 of
the Clear Creek/Central City site was prepared by the U.S. Environmental
Protection Agency (EPA) to describe the issues raised by residents of Clear
Creek and Gilpin Counties regarding EPA's activities in the area and to
summarize EPA's responses to those issues. EPA is conducting a Remedial
Investigation and Feasibility Study (RI/FS) at the site to determine the
nature and extent of contamination that may have resulted from historic mining
activities in the area, and to develop ways of remediating any contamination
found.
A Responsiveness Summary is required under Superfund law to document public
concerns about proposed remedial actions and EPA's responses to those
concerns. This Responsiveness Summary summarizes public comments for the
period that began with the initiation of the Remedial Investigation (RI) of
the site in April 1985, through the public comment period on the Operable Unit
No. 1 FS Report that closed on July 7, 1987. EPA activities, however, are
always open to public review, and this Responsiveness Summary reflects
comments received through September 25, 1987. This report is divided into the
following sections:
Section I. Introduction and Background. This section provides a brief
introduction to the site and EPA's preferred alternatives
for remedial action.
Section II. The Community Relations Program at the Clear Creek/Central
Citv Site. This section provides a brief history of
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Clear Creek/Central City Site
Responsiveness Summary
Page 2
00113
community relations activities conducted by EPA during the
RI/FS at the site.
Section III. Summary of Pub! •!r rnrnmonfg Received and EPA's Responses.
This section summarizes comments received by EPA on Operable
Unit No. 1, categorized as follows:
o Comments and EPA's Responses. Comments received from
inception of the RI/FS on mine drainage through late
September 1987 and EPA's responses to those comments;
and
o Remaining Comments. Comments received for which EPA
will provide more complete answers after further study.
I. INTRODUCTION AND BACKGROUND
Since February 1985, EPA has been investigating public health and
environmental risks posed by metals in mine drainages as a part of the RI/FS
at the Clear Creek/Central City site in Gilpin and Clear Creek Counties. There
has been one RI at the site; the FS has been divided into operable units.
The Proposed Plan that EPA offered for public comment in July 1987 included
passive treatment of mine drainage with the possible inclusion of additional
active treatment later if the need is identified. After considering all the
technical factors and public comments, EPA determined that the appropriate
remedy should include both passive and active treatment.
Community response to the Proposed Plan has been guarded. Residents
expressed misgivings about the need to solve a problem they feel does not
exist -- many area residents would prefer to see the Federal government spend
money to revitalize the economy by helping to reopen mining, rather than to
clean up mine wastes that have not in their minds presented a discernible
threat.
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00113
Clear Creek/Central City Site
Responsiveness Summary
Page 3
Three other alternatives EPA offered for comment are described below.
o No Action would involve only fencing areas where mine drainage is
accessible to the public or enclosing the drainage in pipes. No other
treatment program would be initiated.
o Active Discharge Treatnent would involve the use of lime to remove the
metals from contaminated discharges. Sludge would be produced as a by-product
that would have to be disposed. Some active treatment may be considered later
for the remaining contaminants that passive treatment does not remove.
o Source Control would involve controlling the discharges by sealing them
in the mines or lining streams that feed the mines to prevent additional water
from seeping in.
Several activities with high visibility in the community have been
undertaken during the studies thus far. They are described below.
o Gregory Tailings: A removal action was initiated by EPA at the Gregory
Incline and Tailings in March 1987 to protect the public from hazards
associated with the possible collapse of the tailings into North Clear
Creek. EPA was concerned that collapse of the tailings would wash a
large load of metals downstream into Clear Creek, contaminate the
Golden municipal water supply that is drawn from Clear Creek, and
result in a massive fish kill. EPA also was concerned that a collapse
could cause short-term flooding in the Black Hawk area.
To protect the public and the environment from these hazards, EPA
decreased the slope of the tailings pile to stabilize it and
constructed a temporary retaining wall. EPA originally planned to
implement a remedy at the Gregory Tailings through an Expedited
Response Action (ERA) in the Fall of 1986. Engineering reports were
released in April and June 1986, followed by a public comment period
July 7-28, 1986. EPA was unable to proceed with construction at that
time, however, due to the shortage of funds that preceded
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001132
Clear Creek/Central City Site
Responsiveness Summary
Page 4
reauthorization of the Superfund program. The temporary retaining
wall was built under the EPA Emergency Response program.
o Residential Wells Survey: During the RI/FS, EPA found that shallow
ground water, the source of water for shallow domestic wells, is
contaminated in places with metals including lead, arsenic, cadmium,
zinc, copper, nickel, and chromium. In March and April 1987, EPA
conducted a survey of area households to find out if residents are
using shallow wells. The survey revealed that only a small number of
wells exist, and one private well was contaminated with elevated
levels of cadmium. The owner of that well has been informed of the
elevated levels of cadmium in the well water. A Superfund Removal
Action to address this well is being developed by the Emergency
Removal Branch.
o Passive Treatment Pilot Project: A pilot project for passive
treatment of mine discharge at the Big Five Tunnel portal is now
underway. This project involves construction of a concrete box at the
mine portal to hold some of the mine discharge in front of the portal.
An artificial wetland will be created in the box to study the
efficiency of this technology further in reducing the metal loadings
and neutralizing the acid drainage. EPA expects to use the results of
this project to refine estimates of land requirements and the types of
vegetation most suited to the implementation of this technology for
Operable Unit No. 1.
The draft RI Report and the draft FS Report on mine drainages were
completed and released to the public in June 1987. The RI Report describes
the results of EPA's investigation of the entire site. The FS Report
discusses and evaluates methods of cleaning up mine drainage.
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001132
Clear Creek/Central City Site
Responsiveness Summary
Page 5
II. THE COMMUNITY RELATIONS PROGRAM AT THE CLEAR CREEK/CENTRAL CITY SITE
EPA's community relations activities at the Clear Creek/Central City site
began in the fall of 1982 when the site was placed on the NPL. Since that
time, community concern about EPA's activities at the site has tended to be
moderate, with occasional periods of high interest caused by residents'
concern about the action at the Gregory Tailings and about the Big Five pilot
project. In addition, many local people have been concerned about the fate of
at least two local property owners who may have some liability for cleanup
costs, both of whom are private citizens who live at the site and have many
friends in the communities. In response, EPA representatives have met many
times with local officials, residents, and the press to listen to concerns and
provide information. Much of the community concern has focused on residents'
expressed feelings that mine wastes do not present a problem worthy of the
high level of attention given to this site. In addition, there is a general
antagonism toward the Federal government because of mining regulations that
area residents feel have restricted mining activity in the area.
On several occasions, new information about on-going work at the site has
been the subject of extensive news and editorial coverage in local newspapers,
particularly due to EPA's action at the Gregory Tailings in the Spring of
1987. Residents expressed concern about the cost of and necessity for
conducting the project, particularly in light of the possibility that the
property owner, a local resident, might have to repay the government later for
the costs. The pilot passive treatment project at the Big Five Tunnel portal
has been closely followed in the local newspapers as well. Area residents and
the local newspapers have expressed relatively less interest in the mine
drainage problem than in the Gregory Tailings or the Big Five Tunnel projects.
In preparing the draft Revised Community Relations Plan (CRP) completed in
January 1986, EPA conducted discussions with local officials and community
members in September 1985. The original CRP was prepared in the fall of 1982.
To facilitate the flow of information to the communities, information
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Clear Creek/Central City Site
Responsiveness Summary
Page 6
001132
repositories were established at the Gilpin County Court House in Central
City, the Idaho Springs Public Library in Idaho Springs, and the EPA Library
in Denver in the Fall of 1985. In December 1985, EPA prepared and distributed
to residents an initial Fact Sheet describing the site and the potential
contaminants of concern.
EPA prepared and distributed a second Fact Sheet in July 1986 regarding the
Expedited Response Action planned at the Gregory Tailings for the Fall of
1986. The Agency held a public comment period on the proposed action, and had
a public meeting with local residents. As described in Section II of this
Responsiveness Summary, that action was later conducted as a Superfund Removal
Action in the Spring of 1987. In response to public concern about the cost of
the Removal Action, the potential liability of the property owner, who is a
life-long resident of the community, the potential loss of an historic site,
and the potential for other similar actions in the area, EPA expanded the
number of information repositories to include the Golden Public Library in
Golden, and the Idaho Springs City Hall in Idaho Springs.
Later, in August 1987, EPA placed the full Administrative Record in the
Central City Courthouse and the EPA Library. An index to the Administrative
Record was placed in the other three repositories. In addition, EPA revised
the draft CRP, and signed a Memorandum of Understanding concerning the Gregory
Tailings Removal Action with the Colorado State Historical Society to assure
that the action that EPA undertook at the site was carried out in accord with
state guidelines for preserving historic sites in the area.
During the survey of shallow domestic wells in the Spring of 1987, EPA
prepared a letter to residents and a question-answer Fact Sheet -- both
designed to provide residents with information about the survey and its
purpose -- to be handed out by the individuals taking the survey. Agency
representatives also met with local officials and area residents to discuss
the survey.
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0011325
Clear Creek/Central City Site
Responsiveness Summary
Page 7
The Colorado Historical Society has determined that the Big Five Tunnel
portal is eligible to become a national historic landmark. Thus, EPA
submitted to the State Advisory Council on Historic Preservation drawings of
the passive treatment system at the Big Five Tunnel portal. Upon
recommendation of the Advisory Council, EPA changed the location and materials
of the fence to be built around the passive treatment plant. These changes
were deemed important in preserving historic aspects of the tunnel.
After release in June 1987 of the FS Report on Operable Unit No. 1, EPA
published a question-answer Fact Sheet and held two public meetings in
conjunction with the public comment period from June 8 through July 7, 1987.
The first meeting, in Central City on June 16, had a turnout of about
seventeen people, and only one person asked a question of EPA. A local
property owner later commented to EPA that he felt the public notice for this
meeting was insufficient. He requested an extension of the public comment
period. About forty people attended the second meeting on June 17 in Idaho
Springs. These people had numerous questions and comments, and the atmosphere
at the meeting seemed to be one of questions and reservations about EPA's
plans at the site. Once again, residents expressed doubt about the necessity
for treating mine drainages when they are not perceived as causing any
problems. They also said that the cost of the treatment cast further doubt on
the need for remediation, and expressed concern about the effects of EPA's
activities on the local economy. These concerns are described in greater
detail in Section III.
III. SUMMARY OF PUBLIC COMMENTS RECEIVED AND EPA'S RESPONSES
This section summarizes public concerns expressed about Operable Unit No. 1
during remedial planning at the site through the end of the public comment
period. Community comments generally centered on local economic issues that
may be affected by EPA's actions at the site, and on policy questions about
how EPA first became involved in the area and how EPA sets its priorities.
Several people, most notably the Clear Creek County Metal Mining Association
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0011326
Clear Creek/Central City Site
Responsiveness Summary
Page 8
(CCCMHA) and other area residents at the site, commented that the metals in
mine drainage have economic value. Many comments that EPA received on the
draft FS Report were made by two owners of mining property at the site, both
of whom live in communities at the site.
Aside from local county and municipal governments, the CCCMMA is the only
citizens' group that has expressed interest in EPA's activities. The CCCMMA
includes a broad membership throughout the site and areas downstream. The
residents and CCCMMA suggested that EPA evaluate reclamation of these metals
from the drainage as a way of reducing the public health and environmental
risks at the same time economic return is provided to the communities.
A major concern at the site has been the extent to which EPA's Superfund
activities may adversely impact area property owners and the general prospects
for future mining. A number of citizens have expressed support for area
property owners both encouraging EPA to limit the financial liabilities any
local property owners may have to bear and discouraging EPA from destruction
or removal of the wastes before the minerals can be exploited. These people
and others suggested also that EPA should reevaluate its cleanup priorities --
they said that blowout control is the most important health and environmental
issue at the site and should be addressed first. Blowouts are large explosive
releases of mine drainage from mines whose tunnels were temporarily blocked
for a period of time through natural silting or collapse of mine workings.
The Argo Tunnel has experienced blowouts in the past, with resulting
contamination of Clear Creek downstream to Golden.
During the public meetings, EPA responded that it would examine the
economic benefits of metals reclamation from the mine drainage. The Agency
also agreed that blowout control is an important issue. Noting that blowout
control is currently under study, EPA said that mine drainage remediation is
an initial remedial step that is relatively easily developed and implemented
and treats the baseline, or constant, flow while the difficult question of
blowout control is studied.
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0011327
Clear Creek/Central City Site
Responsiveness Summary
Page 9
The first subsection below provides a summary of comments and GPA's
responses; the second subsection summarizes remaining comments for which EPA
will be able to provide more complete responses after further study.
A. Summary of Comments Received During the Public Comment Period and
Afterwards and EPA1s Responses
This section categorizes questions and comments received during the public
comment period and afterwards, and EPA's responses to those comments in the
categories below.
o Policy Issues. Residents questioned how and why the site was listed on the
National Priorities List (NPL), how the Superfund process would work as
decisions are made and actions taken, how EPA selected water quality
standards for the site, and how EPA would acquire land for a passive
treatment facility.
o Remedial Alternative Issues. In general, residents expressed the opinion
that the mine drainage contains metals with significant economic value,
suggested that EPA address blowout control as a first priority, and urged
EPA to consider reopening the Argo Tunnel as a means of blowout and
drainage control. The Colorado Department of Health (CDH) supported
passive treatment as being relatively cost-effective, but strongly
recommended that EPA consider other methods of remediation -- such as
source control -- that will have even lower long-term costs.
o Technical Issues. CDH recommended that EPA begin tunnel mapping to
expedite investigations of source control, ground water, and blowout
control, and suggested additional tailings characterization and surface
geologic mapping be undertaken. Residents commented that the ground water
may contribute to the contamination problem, and asked how much land would
be needed for a passive treatment facility at the Argo Tunnel portal.
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o Health Issues. Two residents made health-related comments: one said he
had lived at the site for fifty years without negative effects, and the
other suggested that EPA include private wells in its investigation.
o Omnmin-ftv Issues. The Central City Board of Trustees asked EPA to keep it
better informed of activities planned to take place within the city limits.
o Cost Issues. A representative of a resident property owner of Black Hawk
asked whether EPA would leave the question of liability open for a long
time, and another resident commented that studies at the site are costing
too much money.
1. Policy Issues
o Comment: The Mayor of Idaho Springs noted that when the site was
first considered for the National Priorities List (NPL), it initially
received a low Hazard Ranking System (HRS) score. He asked what
prompted the rescoring of the site after the initial low score.
EPA's Response: The preliminary score at the site was based on a
review of available reports. A later field investigation produced
information about the Argo Tunnel blowouts and the importance of this
section of Clear Creek as a critical habitat for aquatic life.
"Critical habitat" refers to the environmental factors that make it
possible for the stream to support the life cycle of animals,
including obtaining food, protecting themselves, and reproducing.
o Comment: A local property owner asked when the HRS site score was
changed sufficiently to cause it to be included on the NPL, and
whether the HRS data were available for review. The Mayor of Idaho
Springs also expressed a desire to see the HRS data, and another
resident asked whether the score can be changed.
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Clear Creek/Central City Site
Re spons ivenes s Summary /
Page 11
EPA's Response: During the Preliminary Assessment, EPA reviewed
initial scoring data, which was based on available reports. The
reviewers determined that a Field Investigation would be needed. The
Field Investigation produced the information about the Argo Tunnel
blowouts and the role of Clear Creek as a critical habitat for aquatic
life. The site was proposed for inclusion on the NPL in 1982. The
change in the initial score occurred during the time when the site was
evaluated for inclusion on the NPL, not at some later date. EPA has
placed the HRS scoring information in the site information
repositories as part of the Administrative Record, but at this time it
is not possible to change the score.
o Comment: The Mayor of Idaho Springs asked to see the EPA criteria
used for ranking the site. He said that if the blowout led to a
higher HRS ranking, then blowout potential should receive priority
treatment.
EPA's Response: The HRS scoring is part of the Administrative Record
that is placed in the information repositories. Blowout study is
underway and the Blowout Control FS Report is scheduled to be issued
for public comment in July 1988. Because of the technical complexity
of the blowout issue, the study cannot be accelerated further.
o Comment: A local property owner asked when EPA expects to select a
remedy for mine drainage and whether it will decide to make this
selection prior to completion of the one-year pilot project at the Big
Five Tunnel portal. The Mayor of Idaho Springs asked whether
construction for the pilot passive treatment project at the Big Five
Tunnel would begin as soon as the remedial action has been selected.
EPA's Response: EPA expects to select a remedy for mine drainage by
the end of September 1987. The primary purpose of the Big Five
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0011330
project is to refine the technology to determine how much land will be
needed, and what kinds of vegetation and organic material will be most
appropriate. Initiation of the project is not dependent upon the
decision for remedial action on mine drainage. EPA is initiating the
pilot project at the Big Five Tunnel portal prior to making a final
decision on the remedial action for mine drainage because the pilot
study will provide EPA with valuable information about how a passive
treatment system should be set up in that area. Seasonal
considerations required that the pilot project be initiated during the
summer months. The project is included as a part of the Proposed Plan
EPA released on June 8, 1987.
o Comment: A resident asked whether EPA has established a baseline or
background figure for water quality in Colorado.
EPA's Response: The State of Colorado has established water quality
standards for all Colorado streams. EPA is committed to cleaning up
the discharges from mine drainages in order to meet Colorado stream
standards wherever possible. Colorado stream standards are based on
protection of human health and aquatic life. These standards may be
higher than background at some points.
o Comment: The Mayor of Idaho Springs said the criteria used by EPA to
evaluate drinking water quality were too stringent. He added that use
of overly stringent concentrations makes the situation appear worse
than it really is.
EPA's Response: EPA responded that national standards for drinking
water were established by Congress under the Federal Safe Drinking
Water Act. These standards are applied uniformly across the country.
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o Comment: The Mayor of Idaho Springs questioned why some area
drainages were included in the FS Report and others were not. He said
that even with cleanup of the five mines, other point source and non-
point source problems would continue to exist. He suggested EPA look
at other sources of contamination. He asked whether EPA has
considered the economic feasibility of restoring Clear Creek water
quality.
EPA's Response: Regarding the concern about continuing sources of
contamination, EPA responded that its studies show that drainage from
the five tunnels is a principal contributor in the degradation of the
water quality of Clear Creek and North Clear Creek. Mine drainage
treatment is just one of the remedial actions that EPA expects to
take, however, and other concerns will be addressed in later studies.
Concerning the question of the economic feasibility of restoring Clear
Creek water quality, the Colorado Department of Wildlife has estimated
that the economic value of Clear Creek as a fishery resource is
$736,000 per year, if Clear Creek is restored to a viable fishery.
EPA has considered the economic feasibility of restoring the water
quality, but it was not a major consideration in the final decision-
making process.
o Comment: The Mayor of Idaho Springs said that the creeks are no
longer stocked with fish below Idaho Springs as they were previously.
He suggested that the RI/FS Report should have considered this fact in
its evaluation of fish populations below Idaho Springs.
EPA's Response: EPA has considered this issue. The Colorado
Department of Wildlife no longer stocks fish below Idaho Springs
because of reduced fish habitat and poor water quality. If the
aquatic habitat is improved, the stream will probably be restocked.
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0011332
o Comment: A local property owner asked how EPA plans to acquire land
for a passive treatment facility, and questioned whether EPA has
condemnation authority.
EPA's Response: EPA has not yet pursued options for acquiring land
for a passive treatment facility. If the Agency encounters a problem
in its efforts to obtain land in one area, it will explore other
options. Although it is not presently contemplating condemnation
proceedings, if necessary, EPA can exercise condemnation authority.
EPA is hopeful that passive treatment locations will constitute a
compatible land use.
o Comment: A local property owner asked whether EPA's decision is
subject to appeal on the grounds that it is not in the best interest
of the local economy.
EPA's Response: One reason that EPA is asking for public comment now
is to be as responsive as possible to community needs in the decision-
making process. EPA's decisions can be changed through a formal
process, although there is no defined period during which appeals can
be made.
o Comment: A local property owner said that individuals who may wish to
appeal a decision need more concrete information about EPA's plans at
the site in order to comment.
EPA's Response: EPA responded that the plans EPA has presented in the
FS Report were as concrete as the Agency had at that time.
o Comment: A local property owner asked if the affected property
owners, the cities, or the counties have input to the final decision
about the treatment.
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EPA's Response: EPA encourages community comments. All comments
received are reviewed during the decision process. EPA expects to
continue to interact with affected property owners as the process
continues to unfold.
2. Remedial Alternative Issues
o Comment: Several commenters expressed the opinion that there is
commercial value to the sludge produced through the active discharge
treatment process. One commenter asked whether EPA will consider the
possibility of resource recovery, adding that the Agency should
consider the potential value of precious metals in the sludge, and in
the mine water. Another commenter said that processing could reduce
the volume of the sludge as much as 50 percent and the value of the
metals would offset the costs of disposal. The President of the Clear
Creek County Metal Mining Association recommended that EPA undertake a
program of research on passive discharge treatment systems to
investigate methods of metals reclamation. The Colorado Department of
Health (CDH) supported this recommendation. It said sludge and
precipitate reprocessing for gold and silver recovery should be
evaluated by assaying the wastes to determine how much precious metal
they contain, and by identifying potential reprocessing technologies
and costs. In earlier studies, the State determined the drainage was
non-hazardous.
EPA's Response: At the public meeting, EPA responded that although it
has not considered the issue of metals reclamation from mine drainage,
the Superfund Amendments and Reauthorization Act (SARA) requires
evaluation of resource recovery and reclamation, and the Agency will
consider this issue before selecting the final remedy. Referring to
the comment that an earlier State study had shown the sludge to be
non-hazardous, EPA said it is required to comply with the laws as they
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001133
exist at the time of treatment. A past determination that the
drainage is non-hazardous may no longer be valid.
o Comment: CDH said it supports the concept of passive treatment
because its long term costs are lower than for active treatment. CDH
added, however, that more discussions are needed on the role of
passive treatment in the treatment sequence. CDH said the same
comment applies to iron oxidation/precipitation,
coagulation/flotation, reverse osmosis, and ion exchange unit
treatment processes. CDH expressed the opinion that detailed costs
presented in Section 3 of the FS Report may not reflect these unit
treatment processes, and are thus too low.
EPA's Response: EPA has subsequently met with CDH and reviewed the
unit treatment processes. The pilot plant that has been constructed
at the Big Five Tunnel will evaluate the removal efficiency of passive
treatment. Active treatment will be added as a polishing step.
o Comment: CDH expressed the opinion that EPA's rejection of source
control alternatives as technically infeasible is premature. It said
consideration should be given to doing remedial design investigations
for channel paving in Lake Gulch to evaluate its effect on flows from
the National Tunnel during Operable Unit No. 1. In any event, CDH
concluded, it is critical that source control evaluations be given the
highest priority, since source control offers the best opportunity for
minimizing long-term costs.
EPA's Response: EPA plans to investigate source control alternatives
for selected areas under Operable Unit No. 3.
o Comment: One commenter noted that the appropriateness of any proposal
would have to be analyzed in detail, particularly with regard to cost
effectiveness and the possible destruction of a valuable economic
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Page 17
asset. Given these two considerations, this party recommended the "No
Action" proposal.
EPA's Response: Consideration of cost effectiveness is the principal
criterion required in the decision- making process. The revised
Superfund legislation requires that priority be given to alternatives
that reduce the mobility, toxicity and volume of wastes. There is no
present indication that mine drainage represents a valuable economic
asset. The No Action alternative is not acceptable, as has been
explained in the ROD.
o Comment: Referring to the Argo Tunnel, a resident noted that passive
treatment is of no value unless the potential for a blowout is
controlled.
EPA's Response: EPA will locate the passive treatment facility away
from the Argo Tunnel portal so that a blowout would not affect it.
Treatment of discharge is a first step in the process of remediation.
Because the remedy must go into the design phase, it will be one to
one-and-a-half years before the Agency actually builds a permanent
passive treatment system. Meanwhile EPA will study blowout control
and reach a decision on the most cost-effective manner to protect
against blowouts.
o Comment: The Mayor of Idaho Springs suggested that EPA re-evaluate
its priorities if blowout was a main consideration in listing the site
on the NPL. He suggested that EPA first address blowout control at
the site.
EPA's Response: EPA has begun to study blowout control; in the
meantime, however, EPA is addressing other important issues related to
metals in the environment. Unless the discharges can be plugged, base
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Clear Creek/Central City Site
Responsiveness Summary
Page 18
flow from the tunnels will always be an issue, and EPA can proceed
with a remedy for it.
o Comment: A resident noted that although the Argo Tunnel blowout
increased the HRS ranking, the Executive Summary of the Rl/FS Report
states that water quality near Golden meets existing drinking water
quality standards. He questioned whether it is essential to spend
money to treat mine drainage. Another resident noted there are two
pathways of human exposure to the contaminants -- wells and municipal
water -- and asked what the pathways were that affected human health
in the ranking of the site.
EPA's Response: In considering potential threats to water quality,
EPA looks at population within three miles of a site, as well as at
all possible pathways of contamination (e.g,. through drinking water).
If a pathway from the contamination to the population exists, that
will raise the score. In the original HRS scoring, it was suspected
that human health was threatened. Subsequent studies indicated,
however, that the primary threat was not to human health, but rather
to the environment. Under the Superfund law, EPA is responsible for
protecting both human health and the environment, however, and must
address both types of problems. Study and action are required at the
site because the creeks do not meet water quality criteria for aquatic
life. The potential also exists for human exposure far downstream if
a blowout were to occur.
3. Technical Issues
o Comment: CDH commented that EPA should begin mine tunnel mapping in
order to expedite investigations of source control, ground water, and
blowout control.
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001133
EPA's Response: EPA believes its files do include all available mine
maps. The Agency is looking further into the availability of
additional maps. EPA has initiated a blowout control study that will
use these maps.
o Comment: A resident asked whether the results from EPA's April 1987
tests of aquifer water quality will be available for review.
EPA's Response: EPA is in the process of writing the reports that
include these findings; these findings will be incorporated into the
Addendum Report to the RI Report, which will be issued in late 1987.
When they are completed, copies will be placed in the information
repositories as part of the Administrative Record.
o Comment: A resident stated that a 1975 study by the State showed
metals concentrations in area wells, and suggested that ground water
may contribute to the contamination problem.
EPA's Response: EPA believes this may be correct, and will study
ground water during Operable Unit No. 6. Meanwhile, EPA's
investigation has also shown that the mine drainages have a
significant impact on the streams, and the Agency is now addressing
this mine drainage problem.
o Comment: A local property owner said that a study done ten to fifteen
years ago showed that water 100 to 150 yards downstream from the Argo
Tunnel portal does not exceed water quality standards.
EPA's Response: EPA's findings do not agree with this statement.
EPA's water quality monitoring studies show that Ambient Water Quality
Criteria are exceeded along Clear Creek as far south as Golden.
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Clear Creek/Central City Site
Responsiveness Summary
Page 20
o Comment: The Mayor of Idaho Springs asked how much land is needed for
passive treatment of the Argo Tunnel drainage.
EPA's Response: EPA estimates that over 200 square feet of land are
needed to treat one gallon per minute of drainage flow. The pilot
project at the Big Five Tunnel portal will help EPA further refine
these estimates. With a 206-gallon-per-minute flow from the Argo
Tunnel, EPA estimates that about one to two acres would be required
for the passive treatment facility for the Argo Tunnel. EPA considers
the question of siting an important one, and will contact the
community again to solicit public comments when it reaches the site
selection stage.
o Comment: A local property owner suggested that further consideration
of passive treatment should be limited to an evaluation of just one
site, and asked whether EPA has considered the Big Five Tunnel site
for such tests.
EPA's Response: The results of the pilot plant program at the Big
Five Tunnel site will be applied to other sites in the area.
o Comment: CDH suggested that additional tailings characterization and
surficial geologic mapping to complete the inventory of tailings/waste
rock piles will be needed to complete the Feasibility Study for
tailings remediation.
EPA's Response: The characterization and mapping have been completed
and will be included in the FS Report on Operable Unit No. 2.
4. Health Issues
o Comment: One resident noted that he has lived in the area for fifty
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Clear Creek/Central City Site
Responsiveness Summary
Page 21
years, and he does not believe that the water quality presents a
health hazard.
EPA's Response: The purpose of the RI/FS process is to determine
scientifically the risks to human health and the environment that
exposure to contaminants at the site may cause. The effects of some
metals may not be observed for years. No human health hazard was
found in the creeks because the metals are diluted by the flow of the
streams. Mine drainage, however, does present human health hazards.
o Comment: The Mayor of Idaho Springs recommended that EPA investigate
health effects from possibly contaminated private wells just outside
the Superfund boundary.
EPA's Response: EPA conducted a well survey in the Spring of 1987 and
determined that an immediate risk does not exist because most people
are using public water supplies that meet the criteria of the Federal
Safe Drinking Water Act. A ground water study will be completed under
Operable Unit No. 6 to evaluate the long-term risks.
5 . r.nmmum'.tV Issues
o Comment: The Central City Council said that EPA should have consulted
with the City Council prior to undertaking activities and making plans
for work within the city limits, and asked EPA to consult with the
City Council on activities already undertaken as well as proposed
activities.
EPA's Response: EPA has subsequently met with the City Council and
agreed to regular consultant meetings. No significant activity has
taken place within the limits of Central City.
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Clear Creek/Central City Site
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o Comment: Representatives of a local property owner requested an
extension of the comment period for community review of the draft RI
and FS Reports, adding that they believe EPA has not done an adequate
job of making the documents available to this individual.
EPA's Response: EPA notified the commenter by letter that comments
would be accepted and considered until mid-September before the ROD is
signed. EPA is always open to public comment at any time.
6. Cost Issues
o Comment: A local property owner commented that the site is the focus
of too much study, adding that such studies are a waste of the
taxpayers' money.
EPA's Response: Whenever possible, EPA attempts to use other studies
and not to duplicate efforts unnecessarily. All of the studies EPA
has conducted to date have been essential to gain a thorough
understanding of the contamination problem at the site.
o Comment: A representative of a local property owner asked whether the
property owner will pay the bill for remediation, or if the question
of financial responsibility will be left open for a long period.
EPA's Response: EPA is conducting a thorough search for all
potentially responsible parties; it is not EPA's intent, however, to
bankrupt anyone.
B. SUMMARY OF REMAINING COMMENTS
Several commenters asked questions that can be answered more thoroughly
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0011
Clear Creek/Central City Site
Responsiveness Summary
Page 23
during later studies. These four remaining comments are summarized below,
followed by EPA's preliminary response.
o £omment: A local property owner asked if EPA has calculated the role
that contaminated ground water plays in contributing metals to the
creeks.
EPA's Response: When EPA began its investigation of the site, it did
not expect ground water to be the focus of study. A ground water
problem was found, however, and EPA plans to study the problem further
under Operable Unit No. 6.
o Comment: A resident asked whether the contamination of Clear Creek
from the ground water originates in the bedrock or the alluvium.
EPA's Response: EPA believes that during periods of high flow, the
stream recharges the ground water; during low flow periods, recharge
is from the aquifer to the stream. EPA has established that the
alluvial ground water is contaminated in some places. It will study
bedrock ground water under Operable Unit No. 6.
o Comment: The President of the Clear Creek County Metal Mining
Association recommended that EPA consider seriously the option of
reopening the Argo Tunnel, cleaning out the cave-ins, and diverting or
grouting the water channels. Two commenters recommended that EPA
consider the benefits of cleaning out the tunnels as a means of
providing economic benefits to the county and the State, and as being
the most viable method of preventing future blowouts. One commenter
added that records will bear out the fact that most of the deposits
above the tunnel are of sufficient value that mines would be reopened
if the tunnel were cleaned out. The other commenter added that
cleaning out the tunnels must be done carefully to minimize safety
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Clear Creek/Central City Site
Responsiveness Summary
Page 24
risks. Further, the Mayor of Idaho Springs stated that blowout
potential exists at several mine adits in the area.
EPA's Response: EPA has initiated a study on blowout control to
protect human health and the environment. Superfund decisions cannot
be influenced by economic benefits that result to the community,
however. A draft FS Report will be available for public review in
July 1988.
o Comment: A local property owner stated that he owns only a small
portion of the land at the Argo Tunnel portal, adding that the Bureau
of Land Management (BLM) owns 99.97 percent of the tunnel.
EPA's Response: EPA is in the process of finalizing a search to
identify potentially responsible parties.
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Responsiveness Summary
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ATTACHMENT 1 TO APPENDIX A
CHRONOLOGY OF COMMUNITY RELATIONS ACTIVITIES AT THE
CLEAR CREEK/CENTRAL CITY SITE
The list below summarizes community relations activities at the Clear
Creek/Central City site. In addition to the activities listed below, EPA has
met with area residents and local officials throughout the RI/FS.
o EPA develops Community Relations Plan (CRP). (October 1982)
o EPA conducts on-site discussions with local officials and area residents.
(September 1985)
o EPA establishes information files at three locations in the local
communities, at the Gilpin County Court House, the Idaho Springs Public
Library, and the EPA Library. (November 1985)
o EPA distributes a kick-off Fact Sheet on the site. (December 1985)
o EPA completes the draft Community Relations Plan. (January 1986)
o EPA releases a question-answer Fact Sheet on the proposed Expedited
Response Action at the Gregory Tailings, holds a public comment period, and
sponsors a public meeting on the ERA. (July 1986)
o EPA holds a public meeting on the proposed Emergency Removal Action at the
Gregory Tailings, and signs a Memorandum of Understanding with the Colorado
Historical Society. (March 1987)
o In response to community requests, EPA expands the number of local-area
information repositories to include the Golden Public Library and the Idaho
Springs City Hall. (May 1987)
o EPA releases a question-answer Fact Sheet on the well survey and writes an
open letter to residents. (April 1987)
o EPA revises the draft CRP. (June 1987)
o EPA distributes a question-answer Fact Sheet, holds a public meeting, and
has a public comment period on the RI/FS and Proposed Plan for Operable
Unit No. 1. (June-July 1987)
o EPA places the Administrative Record in the information repositories at the
Gilpin County Court House and the EPA Library. (August 1987)
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ADMINISTRATIVE RECORD
SF FILE NUMBER
APPENDIX B »>, |
APPLICABLE AND/OR RELEVANT AND APPROPRIATE FEDERAL AND STATE REQUIREMENTS
INTRODUCTION
Under section 121(d) (1) of the Superfund Amendments and Reauthorization
Act of 1986 ("SARA"), remedial actions must attain a degree of cleanup
which assures protection of human health and the environment.
Additionally, Superfund remedial actions that leave any hazardous
substance, pollutant, or contaminant onsite 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
and/or relevant and appropriate" under the circumstances of the release.
These requirements, known as "ARARs", may be waived in certain instances.
(Section 121(d)(4) of SARA.)
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 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.
Subsection 121(d) of SARA requires that Federal and State substantive
requirements that qualify as ARARs be complied with by remedies (in the
absence of a waiver). State requirements can be waived if a State has not
consistently applied or 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 to be obtained for removal or remedial actions
implemented on site (Subsection 121(e) of SARA).
B-l
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The definition of "applicable" and "relevant or appropriate" requirements
is derived from the National Contingency Plan, AO C.F.R. § 300.6 (1986)
("NCP"). "Applicable" requirements are those that would be legally
applicable to a remedial action except that the action is being taken
pursuant to CERCLA authority. Applicable requirements may apply directly
or through incorporation by a Federally authorized State program.
"Relevant and appropriate" requirements are not legally applicable, but are
designed to apply to problems or situations sufficiently similar that their
application is appropriate. For example, requirements may be relevant and
appropriate if they would be "applicable" but for jurisdictional
restrictions associated with the requirement.
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 historic sites. The third type of
ARAR includes action-specific requirements. These are technology-based
restrictions which are triggered by the type of action under consideration.
Examples of action-specific ARARs are Resource Conservation and Recovery
Act (RCRA) regulations for waste treatment, storage, and disposal.
ARAR IDENTIFICATION PROCESS
EPA and the State of Colorado reviewed, respectively, Federal and State
laws, standards, requirements, criteria, and limitations for possible
application to the Clear Creek/Central City site. Tables B-l and B-2
contain a listing of the potential ARARs screened by EPA and the State.
These charts identify each potential ARAR and whether or not it is
B-2
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"applicable" or "relevant and appropriate." The remainder of this analysis
describes the three types of ARARs identified for Operable Unit No. One in
greater detail.
CONTAMINANT-SPECIFIC ARARs
The contaminant pathways of concern are discharge from five distinct
tunnels to Clear Creek and North Clear Creek surface water and subsequent
interactions with shallow ground water. The principal contaminants include
but are not limited to arsenic, cadmium, chromium, copper, fluoride, lead,
nickel, silver and zinc. Humans are a potential receptor of contamination
from discharge through exposure to both contaminated acid mine drainage and
ground water. Aquatic life is exposed to contaminated surface water.
Contaminant-Specific ARARs
The contaminant-specific ARARs for Operable Unit No. One are described
below and listed in Tables B-l through B-3.
1. Maximum Contaminant Levels for Drinking Water
The Federal Safe Drinking Water Act and Colorado drinking water
authorities provide for the establishment of drinking water
standards for public water systems. These standards are
"applicable" only to public water systems as defined by the Act and
regulations. However, they may be considered "relevant and
appropriate" as ARARs for potential ground water and surface water
exposure via drinking water (U.S. EPA, Superfund Public Health
Evaluation Manual (Oct. 1986)). Because of the connection at the
site between surface water and ground water which is an existing or
potential source of drinking water, drinking water standards are
considered ARARs for Operable Unit No. One.
The primary "maximum contaminant levels" or MCLs" for inorganic
chemicals are considered ARARs. Primary MCLs are enforceable
standards establishing maximum permissible levels of contaminants
in drinking water. (AO C.F.R. § 141.2(c) (1986)). These standards
are health-based, but have an economic component. (42 U.S.C. §
1401(1)(C)). Primary MCLs are currently set for the following
chemicals: arsenic, barium, cadmium, chromium, lead, mercury,
nitrate, selenium, and silver. (40 C.F.R. § 141.11(b)). The
B-3
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Federal and State MCLs for these substances are identical.
(Colorado Primary Drinking Water Regulations, 5 Colo. Admin. Code
1003-1 (1981)). MCLs are less stringent than AWQC.
The Safe Drinking Water Act also provides for establishment of
secondary MCLs. These are designed to "control contaminants in
drinking water that primarily affect the aesthetic qualities
relating to public acceptance of drinking water." 40 C.F.R. §
143.1 (1986). The regulations note that secondary MCLs "in the
judgment of the Administrator (of EPA) are requisite to protect the
public welfare." 40 C.F.R. § 143.2(f). Federal secondary MCLs are
set for chloride, color, copper, corrosivity, fluoride, foaming
agents, iron, manganese, odor, pH, sulfate, total dissolved solids,
and zinc. 40 C.F.R. § 143.3. The State of Colorado has not
promulgated secondary MCLs.
Federal Ambient Water Quality Criteria
Section 304(a) of the Clean Water Act, 33 U.S.C. § 1314(a) (1982),
requires EPA to develop water quality criteria related to
protection of human health and aquatic life. EPA has developed
criteria for numerous substances. The Federal water quality
criteria are not legally enforceable and are therefore not
"applicable" to the cleanup. However, they may be considered
"relevant and appropriate" under the circumstances of the release.
Under section 121(d)(2) (A) of SARA, the remedy selected must
"require a level or standard of control which at least attains ...
water quality criteria established under section 304 or 303 of the
Clean Water Act, where such ... criteria are relevant and
appropriate under the circumstances of time release or threatened
release." SARA further provides that "(i) in determining whether
or not any water quality criteria under the Clean Water Act is
relevant and appropriate under the circumstances of the releases,
(EPA) shall consider the designated or potential use of the surface
or ground water, the environmental media affected, the purposes for
which such criteria were developed, and the latest information
available." (Section 121(d)(2)(B)(i) of SARA.)
EPA has determined that the ambient water quality criteria for
acute and chronic toxicity to fresh water aquatic life and to
humans for arsenic, cadmium, chromium, copper, cyanide, iron, lead,
mercury, nickel, selenium, silver, and zinc are relevant for
Operable Unit No. One. Additional data collection and analysis are
necessary for EPA to determine whether such National criteria are
appropriate under the circumstances of these releases into Clear
Creek and North Clear Creek or whether site specific modifications
to national criteria would more appropriately establish a cleanup
goal for this site. Until such time that it is determined that
site specific modification to individual contaminant criteria are
B-4
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-¦v-
0011348
necessary, EPA will consider the more stringent of human health or
aquatic life ambient water quality criteria (AWQCs) as an ARAR for
the final remedy.
3. State Water Quality Standards
Section 303 of the Clean Water Act, 33 U.S.C. § 1313, provides for
promulgation of water quality standards by the States. The
standards consist of designated uses of water and water quality
criteria for water based on uses designated. 40 C.F.R. § 131.3(i)
(1986). The criteria are "elements of State water quality
standards, expressed as constituent concentrations, levels, or
narrative statements, representing a quality of water that supports
a particular use." 40 C.F.R. § 131.3(b).
a. State Contaminant-Specific ARARS
State contaminant-specific ARARs are listed in Table B-l and B-3.
Table B-l compares Federal MCLs, AWQC and State
Contaminant-specific ARARs. State contaminant-specific ARARs are
considered relevant, but to the extent that they are duplicative of
Federal AWQC, their appropriateness for this site has to be
evaluated.
b. Colo. Admin. Code 1002-8.
The State has also identified the "basic standards" portion of "The
Basic Standards and Methodologies" as an ARAR for Operable Unit No.
One. (5 Colo. Admin. Code 1002-8.) Section 3.1.11 of these
regulations establishes basic standards applicable to all waters of
the State. The key portions of these standards which are relevant
and appropriate for Operable Unit No. One state:
Substances attributable to human-induced discharges ... shall not
be introduced into waters of the State:
a. which can settle to form bottom deposits detrimental to the
beneficial uses. Deposits are stream bottom buildup of
materials which include but are not limited to anaerobic
sludges, mine slurry or tailings, silt, or mud; or
b. which form floating debris, scum, or other surface materials
sufficient to harm existing beneficial uses; or
c. which produce color, odor, or other conditions in such a degree
as to create a nuisance or harm existing beneficial uses or
impart any undesirable taste to significant edible aquatic
species or to the water; or
d. in amounts, concentrations, or combinations which are harmful
to the beneficial uses or toxic to humans, animals, plants, or
aquatic life; or
B-5
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0011349
e. in amounts, concentrations, or combination which produce a
predominance of undesirable aquatic life; or
f. in concentrations which cause a film on the surface or produce
a deposit on shorelines.
C. Antidegradation Standard
The State of Colorado has also identified its antidegradation
standard as an MAR for the Operable Unit No. One. Section 3.1,8
of The Basic Standards and Methodologies, 5 Colo. Admin. Code
1002-8, provides:
Existing uses shall be maintained as required by State and
Federal law. No further water quality degradation is allowable
which would interfere with or become injurious to existing
uses.
Under section 3.1.3, the antidegradation standard applies to all
waters of the State and is considered relevant and appropriate for
Operable Unit No. One.
State regulations do not define the term "existing uses". Under
Federal regulations, existing uses are defined as "uses actually
attained in the water body on or after November 28, 1975, whether
or not they are included in the water quality standards." (40
C.F.R. § 131.10.)
LOCATION-SPECIFIC ARARs
Physical characteristics of the site influence the type and location of
remedial responses considered for Operable Unit One. The location-specific
ARARs identified for the site in Tables B-l through B-3 establish
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 for Operable Unit No. One 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.
B-6
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0011350
1. Historic Preservation ARARs
Both Federal and State laws provide for protection of historical
resources. The Central City Historic District is located within
the Superfund site. In addition, there may be features eligible
for the Federal or State historical registers. All regulations
relating to historic preservation will be followed.
2. Fish and Wildlife
The Fish and Wildlife Coordination Act requires EPA to coordinate
with Federal and State agencies if the remedy would modify any
stream or water body. If any remedy selected involves modification
of Clear Creek, or North Clear Creek, EPA will work with these
agencies to provide for protection of fish and wildlife.
3. Floodplains
Portions of the site along North Clear Creek are in the floodplain.
Facilities will be situated out of the floodplain for Operable Unit
No. One. Requirements of the Executive Order on Floodplain
Management are applicable to this operable unit.
4. Wetlands
The Executive Order on protection of wetlands is applicable for
this operable unit.
5. Work in or Affecting Navigable Waters
If the remedy selected for Operable Unit No. One involves work in
or affecting navigable waters, EPA will follow all relevant ARARs
under Section 404 of the Clear Water Act.
Action-Specific ARARs
The action-specific ARARs for Operable Unit No. One deal with requirements
for the degree of discharge treatment required and requirements for
disposal of sludges and metal laden organic material.
1. National Pollutant Discharge Elimination System (NPDES)
The degree of treatment required for low pH mine discharges will be
sufficient to meet upstream water quality concentrations in Clear
Creek and North Clear Creek. The NPDES effluent limitations would
not be as stringent.
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0011351
2. Solid Waste Disposal Act (SWDA)
The SWDA sets criteria for landfilling of sludges and would also
impose a land ban on landfilling of metal laden organic material
removed from passive treatment systems, if not treated to pass EP
toxicity tests. The SWDA is an ARAR. Subtitle D of RCRA is
considered relevant and appropriate upon implementation.
B-8
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TABLE B-l
PCmNIIAL APPLICABLE CR RELEVANT AM) APPROHOAIE CRITERIA
PEPnNENT TO CLEAR CEEEK/CENIRAL CITY SITE
mg/L
Contaminant
of Concern
MCL
(SCWA)
AWQC ,
Hunan Health
(CVA)
AWQC
Aquatic Life
(CWA)
CEB
Contaminant Specific
ARARs
CDB Method
Effluent Limitations Detection
Bid of Pipe Limit0
Aluninun (Al)
Arsenic (As)
Cadmiun (Cd)
Copper (Cu)
Fluoride (F)
Lead (Pb)
Manganese (Mn)
(Total)
Nickel (Ni)
0.Q50
0.010
Chromium (Cr) 0.05 (hex)
(Total)
4.03
0.050
0(2.2 ng/L)
0.010
0.05 (hex)
179.0 (tri)
1.0
organoleptic
0.050
0.015
0.15
0.19f
0.00066g'h
0.0072 (hex)
0.042 (tri)
0.0065g'i
o.oor#'k
0.088
d,g
0.05
0.003 (CC)
0.0004 (NOC)
1.4-2.4
1.0
0.1/0.05
0.3/0.15
0.6/0.3
0.025
0.003
0.001
0.010
0.003
0.002
0.015
0.040
o
o
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TABLE B-l
POTENTIAL APPLICABLE CR RELEVANT AMD APPROPRIATE CRTTERIA
PERTINENT TO CLEAR CREEK/dNTRAL CLTY SHE
mg/L
AW3C ,
AMX
cm
OB
Method
Contaminant
Haa
Hunan Health
Aquatic Life
Contaminant Specific
Effluent Limitations
Detection
of Concern
(SDWA)
(CMA)
(CWA)
ARARs
End of Pipe
Limit0
Silver (Ag)
0.050
0.050
O.OO^'1
0.0001
—
0.010
Zinc (Zn)
5.0
0.047g,m
1.5/0.75
0.002
organoleptic
^ CFR 40, Part 141, Subpart B, 141.11.
Superfund Public Health Evaluation Manual, December 18, 1985, OSWER Directive 9285.4-1.
j For CDM data.
Federal Register, Vol. 51, No._^7, March 11, 1986, p. 8362 (proposed value).
® Value in parenthesis equals 10 carcinogenic risk level.
Federal Register, Vol. 50, No. 145, July 29, 1985.
® At hardness of 50 mg/L CaCCL, four day average concentration.
. AnMent Water Quality Criteria for Cadmium, EPA 440/5-84/032, January 1985.
] Ambient Water Quality Criteria for Copper, EPA 440/5-84/031, January 1985.
P Federal Register, Vol. 51, No. 63, April 2, 1986, p. 113%.
, Ambient Water Quality Criteria for Lead, EPA 440/5-84/027, January 1985.
Federal Register, Vol. 45, No. 231, November 28, 1980, p. 79340.
111 Federal Register, Vol. 51, No. 102, May 28, 1986, p. 19269.
n Standard Units.
° One day maxijnuni/30 days average, respectively. O
O
Note: All values are "total recoverable" concentrations except for Aquatic AWQC for As, Cd, Cu, Pb which are acid soluble.
CO
CJTf
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TABLE B-2
HDfcKAL ARARs
Standard, Requirement,
Criteria, or Limitation
Citation
Description
Applicable/
Relevant and
Appropriate
Caiment
Contaminant-Specific
Safe Drinking Water Act
National Primary
Drinking Water
Standards
National Secondary
Drinking Water
Standards
Maximum Contaminant
Level Goals
Clean Water Act
Water Quality
Criteria
40 U.S.C. § 300g
40 C.F.R. Part 141
40 C.F.R. Part 143
Pub. L. No. 99-339,
100 Stat. 642 (1986)
33 U.S.C. §§
1251-1376
40 C.F.R. Part 131
Quality Criteria for
Water, 1976, 1980,
1986
Establishes health-based standards
for public water systems (maxirrun
contaminant levels)
Establishes welfare-based
standards for public water systems
(secondary maximm contaminant
levels)
Establishes drinking water quality
goals set at levels of no known or
anticipated adverse health
effects, with an adequate margin
of safety
No/Yes
No/Yes
No/No
Sets criteria for water quality
based on toxicity to aquatic
organisms and human health
No/Yes
The MCLs for inorganic
contaminants are relevant and
appropriate. They are less
stringent than AWQC for
aquatic life.
Secondary MCLs for inorganic
contaminants are relevant and
appropriate.
Proposed MCLG's for inorganic
contaminants are found in the
Nov. 13, 1985, Federal
Register. These should be
treated as "other criteria,
advisories, and guidance."
Notices of availability of
final criteria docunents for
nickel and zinc were
published in the December 3,
1986, and March 2, 1987
Federal Registers.
O
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TABLE B-2 (cent.)
FHJEEAL ARARs
Standard, Requirement,
Criteria, or limitation
Citation
Description
Toxic Pollutant
Effluent Standards
Identification and
Listing of Hazardous
Waste
40 C.F.R. Part 129
40 C.F.R. Part 261
Establishes effluent standards or
prohibitions for certain toxic
pollutants: aldrin/dieldrin, EOT,
endrin, toxaphene, benzidine, PCBs
Defines those solid wastes which
are subject to regulation as
hazardous wastes under 40 C.F.R.
Parts 262-265 and Parts 124, 270,
271.
Action-Specific
Clean Water Act 33 U.S.C. §§
1251-1376
National Pollutant 40 C.F.R. Parts 122, Requires permits for the
Discharge Elimination 125 discharge of pollutants from any
System point source into waters of the
United States
Applicable/
Relevant and
Appropriate Carment
No/No These pollutants are not
present in effluent.
No/No Creates no substantive
cleanup requirements. Ihder
40 C.F.R. § 261.4(b)(7),
solid waste from the
extraction, beneficiation,
and processing of ores and
minerals is not hazardous
waste. However, under
CERCLA, SWDA requirements maty
be relevant and appropriate
under the circumstances of
the release at the site. In
this chart, any solid wastes
which pose a threat to public
health or welfare or the
environment are termed
"hazardous materials."
O
O
Yes/Yes A permit is not required for M*
on-site CERCLA response
actions, but the substantive W
requirements apply. Permit ^
requirements currently
utilized by CEH are less
stringent than AHQC.
CJ7
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TABLE B-2 (cont.)
FEEERAL ARARs
Standard, Requirement,
Criteria, or Limitation
Citation
Description
Applicable/
Relevant and
Appropriate
Oomnent
Effluent Limitations
40 CFR Part 440
National Pretreatment
Standards
40. C.F.R. Part 403
Solid Waste Disposal Act
("SWDA")
Criteria for
Classification of
Solid Waste Disposal
Facilities and
Practices
42 U.S.C. §§
6901-6987
40. C.F.R. Part 257
Sets technology-based effluent Yes/Yes
limitations for point source
discharges in the Ore Mining and
Dressing Point Source Category.
Sets standards to control No/No
pollutants which pass through or
interfere with treatment processes
in publicly owned treatment works
or which may contaminate sewage
sludge
Establishes crieria for use in Yes/Yes
determining which solid waste
disposal facilities and practices
pose a reasonable probability of
adverse effects on health or the
environment and thereby constitute
prohibited open dumps
Less stringent than AW3C.
The alternatives developed
do not include discharge to a
publicly owned treatment
works.
The current Subtitle D
program is principally aimed
at nunicipal and industrial
solid waste and does not
fully address mining waste
concerns. Subtitle D is
currently being revised to
address mining wastes. Any
new Subtitle D requirements
are considered relevant and
appropriate.
O
O
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to
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TABUS R-2 (cont.)
FEDERAL ARARs
Applicable/
Standard, Requiremait, Relevant and
Criteria, or Limitation Citation Description Appropriate Comnent
Guidelines for the
Land Disposal of
Solid Wastes
40 C.F.R. Part 241
Establishes requirements and
procedures for land disposal of
solid wastes
No/Yes
Standards Applicable
to Generators of
Hazardous Waste
40 C.F.R Part 262
Establishes standards for
generators of hazardous waste
No/Yes Only relevant and appropriate
if sludge disposal alterna-
tive developed would involve
off-site transportation of
hazardous materials.
Standards Applicable
to Transporters of
Hazardous Waste
40 C.F.R. Part 263
Establishes standards which apply
to persons transporting hazardous
waste within the U.S. if the
transportation requires a manifest
under 40 C.F.R. Part 262
No/Yes Only relevant and appropriate
if sludge disposal alterna-
tive developed would involve
off-site transportation of
hazardous materials.
Standards for Owners
and Operators of
Hazardous Waste
Treatment, Storage,
and Disposal
Facilities
40 C.F.R. Part 264
Establishes minimum national
standards which define the
acceptable management of hazardous
waste for owners and operators of
facilities which treat, store, or
dispose of hazardous waste
No/Yes Part 264 would apply to
sludge only if it were a
hazardous waste. A R.C.R.A.
TSD facility is not being
built.
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TABLE B-2 (cont.)
FEDERAL ARARs
Applicable/
Standard, Requirement, Relevant and
Criteria, or Limitation Citation Description Appropriate Comment
Interim Standards for
Owners and Operators
of Hazardous Waste
Treatment, Storage,
and Disposal
Facilties
40 C.F.R Part 265
Establishes ndninun national
standards that define the
acceptable management of hazardous
waste during the period of interim
status and until certification of
final closure, or if the facility
is subject to post-closure
requirements, until post-closure
responsibilities are fulfilled
No/No
Remedies should be consistent
with the more stringoit Part
264 standards as these
represent the ultimate RCRA
compliance standards and are
consistent with CERCXA's goal
of long-term protection of
public health and welfare and
the environment.
Standards for the
Management of
Specific Hazardous
Wastes and Specific
Types of Hazardous
Waste Management
Facilities
40 C.F.R. Part 266
Establishes requirements which
apply to recyclable materials that
are reclaimed to recover
economically significant amounts
of precious metals, including gold
and silver
No/Yes Does not establish additional
cleanup requirements.
O
O
H4-
to
CTf
00
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TABUS B-2 (cent.)
FEDERAL ABARs
Applicable/
Standard, Requirement, Relevant and
Criteria, or Limitation Citation Description Appropriate Consent
Interim Standards for
Owners and Operators
of New Hazardous
Vaste Land Disposal
Facilities
40 C.F.R. Part 267
Establishes minimum national
standards that define acceptable
management of hazardous vaste for
new land disposal facilities
No/No
Remedies should be consistent
with the more stringent Part
264 standards as these
represent the ultimate RCRA
compliance standards and are
consistent with CERCXA's goal
of long-term protection of
public health and welfare and
the environment.
Land Disposal
Criteria
40 C.F.R. Part 268
Yes/Yes Requirements for landfill
disposal of metal laden
organic material apply.
Hazardous Waste
Permit Program
40 C.F.R. Part 270
Establishes provisions covering basic No/No
EPA permitting requirements
A permit is not required for
on-site (ERCLA response
actions. Substantive
requirements are addressed in
40 C.F.R. Part 264.
Underground Storage
Tanks
40 C.F.R. Part 280
Establishes regulations related to
underground storage tanks
No/No
Use of undergound storage
tanks are not being
considered.
Occupational Safety and
Health Act
29 U.S.C §§ 651-678
Regulates wsrker health and
safety.
Yes/Yes Uhder 40 C.F.R. § 300.38,
requirements of this Act
apply to all response
activities under the NCP.
O
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TABLE B-2 (cont.)
FEDERAL ARABs
Applicable/
Standard, Requirement, Relevant and
Criteria, or limitation Citation Description Appropriate Gomnait
Federal Mine Safety and
Health Act
30 U.S.C. §§ 801-962
Regulates working conditions in
underground mines to assure safety
and health of workers.
Yes/Yes Ihder 40 C.F.R. § 300.38, all
applicable health and safety
requirements apply to all
response activities under the
NCP.
Hazardous Materials
Transportation Act
Hazardous Materials
Transportation
Regulations
Location-Specific
National Historic
Preservation Act
49 U.S.C. §§
1801-1813
49 C.F.R. Parts 107,
171-177
16 U.S.C. § 470
40 C.F.R. § 6.301(b)
36 C.F.R. Part 800
Regulates transportation of
hazardous materials.
Requires Federal agencies to take
into account the effect of any
Federally-assisted undertaking or
licensing on any district, site,
building, structure, or object
that is included in or eligible
for inclusion in the National
Register of Historic Places.
Yes/Yes ARAR only if an alternative
developed would involve
transportation of hazardous
materials.
Yes/Yes If the remedy would affect
any district, site, building,
structure, or object listed
on or eligible for the
National Register.
O
O
CO
o
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TABLE B-2 (cont.)
FEDERAL ARARs
Applicable/
Standard, Requirement, Relevant and
Criteria, or Limitation Citation Description Appropriate Caiment
Archeological and
Historic Preservation
Act
Historic Sites, Buildings
and Antiquities Act
Fish and Wildlife
Coordination Act
16 U.S.C. § 469
40 C.F.R. § 6301(c)
16 U.S.C. §§ 461-467
40 C.F.R.§ 6.301(a)
16 U.S.C. §§ 661-666
40 C.F.R. § 6.302(g)
Establishes procedures to provide Yes/Yes
for preservation of historical and
archeological data which might be
destroyed through alteration of
terrain as a result of a Federal
construction project or a
Federally licensed activity or
program.
Requires Federal agencies to Yes/Yes
consider the existence and
location of landmarks on the
National Registry of Natural
Landmarks to avoid undesirable
impacts on such landmarks.
Requires consultation when Federal Yes/Yes
department or agency proposes or
authorizes any modification of any
stream or other water body and
adequate provision for protection
of fish and wildlife resources.
Portions of the site are in
National Historic
Preservation Areas.
Portions of the site are in
National Historic
Preservation Areas.
Alternatives developed may
modify streams.
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TABLE B-2 (cent.)
FHBRAL ARABs
Standard, Requiranent,
Criteria, or Limitation
Citation
Description
Clean Water Act
Dredge or Fill
Requirements
(Section '404)
33 U.S.C. §§
1251-1376
40 C.F.R. Parts 230,
231
33 C.F.R. Part 323
Requires permits for discharge of
dredged or fill material into
navigable waters.
Rivers and Harbors Act of 33 U.S.C § 403
1899
Section 10 Permit
33 C.F.R. Parts
320-330
Requires permit for structures or
work in or affecting navigable
waters.
Executive Order on
Protection of Wetlands
Exec. Order No.
11,990
40 C.F.R. § 6.302(a)
& Appendix A
Requires Federal agencies to
avoid, to the extent possible, the
adverse impacts associated with
the destruction or loss of
wetlands and to avoid support of
new construction in wetlands if a
practicable alternative exists.
Applicable/
Relevant and
Appropriate Comnait
Yes/Yes
Yes/Yes
Yes/Yes
A permit is not required for
onsite CEBCLA response
actions, but substantive
requirements would be met if
an alternative developed
would involve discharge of
dredged or fill material into
navigable waters. This is
not anticipated.
A permit is not required for
onsite GStCLA response
actions, but substantive
requirements would be met if
an alternative developed
would involve structures or
work in or affecting
navigable waters.
If an alternative developed
would affect a wetland. This ®
is not anticipated.
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TABLE B-2 (cent.)
FEDERAL ARARs
Standard, Requirement,
Criteria, or Limitation
Citation
Description
Applicable/
Relevant and
Appropriate
Conrnent
Executive Order on
Floodplain Management
Exec. Order No.
11,988
40 C.F.R. § 6.302(b)
& Appendix A
Requires Federal agencies to
evaluate the potential effects of
actions they may take in a
floodplain to avoid, to the
maximum extent possible, the
adverse impacts associated with
direct and indirect development of
a floodplain.
Yes/Yes If an alternative developed
would affect a floodplain.
This is not anticipated.
O
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TABLE B-3
COLORADO ARARs
EFFLUENT LIMITATIONS*
Colorado Applicable/
Contaminant Specific Relevant and
Contaminant Unit ARAR Title and Section of State Standard Appropriate Consents
pH standard units
6.0 - 9.0
5
CCR
1002-3,
Sect. 10.1.4.
Yes/Yes
Fecal Coliform
No./lOO ml
200
So/So
Not identified
contaminant of
as
concern
Total Suspended Solids
mg/L
30/20b
5
CCR
1002-3,
Sect. 10.1.3, 40
CFR
Part
440.102
Yes/yes
Biological Oxygen Demand
BODg
45/30C
5
CCR
1002-3,
Sect. 10.1.4.
No/No
Not identified
contaminant of
as
concern
oil and Grease
mg/L
10/No visible sheen
5
CCR
1002-3,
Sect. 10.1.4.
Yes/Yes
Residual Chlorine
mg/L
0.5 maximum
5
CCR
1002-3,
Sect. 10.1.4.
Ho/Wo
Not identified
contaminant of
as
concern
Cadmium
mg/L
0.1/0.050b
5
CCR
1002-3,
Sect. 10.1.3; 40
CFR
Part
440.103
Yes/Yes
Copper
mg/L
0.3/0.15b
5
CCR
1002-3,
Sect. 10.1.3; 40
CFR
Part
440.103
Yes/Yes
Lead
mg/L
0.6/.3b
5
CCR
1002-3,
Sect. 10.1.3; 40
CFR
Part
440.103
Yes/Yes
Mercury
mg/L
0.002/.001b
5
CCR
1002-3,
Sect. 10.1.3; 40
CRR
Part
440.103
Yes/Yes
Zinc
mg/L
1.5/.750b
5
CCR
1002-3,
Sect. 10.1.3; 40
CFR
Part
440.103
Yes/Yes
a End of pipe value. If effluent limitations based on in-stream numeric standards are stricter, the stricter numbers apply.
b One day maximum/30 day average, respectively.
c 7 day average/30 day average, respectively.
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TABLE B-3
COLORADO ARARs
CONTAMINANT-SPECIFIC ARARs WATER QUALITY LIMITED
immant
Colorado
Contaminant-Specific
ARARb
Units
Title and Section of State Standard
Leal and Biological
(standard units)
rbidity
ssolved Oxygen
mperature (°C)
cal Coliform
6.5 - 9.0
7.0
20®/max 3° increase
200
Standard
Utiits
turbidity
units
mg/L
°C
No/100 ml
5 CCR 1002-3, Sect. 3.8.6, Region 3
Segments 2, 11, 13
5 CCR 1003-1, Article 4
5 CCR 1002-8, Sect. 3.8.6, Region 3
Segments 2, 11, 13
5 CCR 1002-8, Sect. 3.8.5
5 CCR 1002-8, Sect. 3.8.5
ganics
monia (unionized)
trite
iloride
ilfate
ranide (Free)
0.020
0.050
250
250
0.005
mg/L
mg/L
mg/L
mg/L
mg/L
5 CCR 1002-8, Sect. 3.8.6, Region 3
Segments 11, 13
5 CCR 1002-8, Sect. 3.8.6, Region 3
Segment 11
5 CCR 1003-1, Article 5
5 CCR 1002-8, Sect. 3.8.6, Region 3
Segment 11
5 CCR 1002-8, Sect. 3.8.6, Region 3
Segment 11
5 CCR 1002-8, Sect. 3.8.6, Region 3
Segments 2, 11, 13
Applicable/
Relevant and
Appropriate
Coments
Yes/Yes —
No/No not identified as contaminant
of concern
No/No Rot identified as contaminant
of concern
Yes/Yes —
No/No Rot identified as contaminant
of concern
No/No Rot identified as contaminant
of concern
No/No Rot identified as contaminant
of concern
Mo/No
Ho/No Rot identified as contaminant
of concern
No/No Rot identified as contaminant
of concern
No/No Rot identified as contaminant
of concern
-------
TABLE B-3 (cont.)
COLORADO ARARs
CONTAMINANT-SPECIFIC ARARs WATER QUALITY LIMITED
Colorado Applicable/
Contaminant-Specific Relevant and
Contaminant ARAR^ Units Title and Section of State Standard Appropriate Contents
Boron
0.750
mg/L
5 CCR 1002-8, Sect. 3.8.6, Region 3,
Segments 2, 11, 13
No/No Rot identified as contaminant
of concern
Sulfur (as H^S)
0.002
rag/L
5 CCR 1002-8, Sect. 3.8.6, Region 3,
Segments 2, 11, 13
So/So Rot identified as contaminant
of concern
Residual Chlorine
rag/L
5 CCR 1002-8, Sect. 3,8.6, Region 3,
Segments 2, 11, 13
No/No Hot identified as contaminant
of concern
Metals
Aluminum
Arsenic
0.150
0.050
mg/L
mg/L
5 CCR 1002-8, Sect. 3.8.6, Region 3,
Segments 2, 11, 13
5 CCR 1003-1, Article 5
Yes/Yes
Yes/Yes
Barium
Beryllium
Cadmium
1
0.0053
0.0004® (HCC)
0.003 (CC)
mg/L
rag/L
mg/L
5 CCR 1003-1, Article 5
5 CCR 1002-8, Sect. 3.8.6, Region 3,
Segment 13 protects aquatic life from
chronic toxicity.
Yes/Yes
Yes/Yes
Yes/Yes
o
o
M.
CO
C5
OS
-------
TABLE B-3 (cont.)
COLORADO ARARs
CONTAMINANT-SPECIFIC ARARs MATER QUALITY LIMITED
Contaminant
Colorado
Contaninant-Specific
ARARb
Uhits
Applicable/
Relevant and
Title and Section of State Standard Appropriate
Coanents
Chromium (III)
0.039
mg/L
5 CCR 1003-1, Article 5. Total
Chromium cannot exceed 50
Yes/Yes
Chromium (VI)
0.011
mg/L
Yes/Yes
Copper
0.0065
a
mg/L
Yes/Yes
Fluoride
Gross Alpha
1.4 - 2.4
15
mg/L
pCi/L
5 CCR 1003-1, Article 5
5 CCR 1003-1, Article 7
Yes/Yes
No/No
Not identified as contaminant
of concern
Iron (Soluble)
0.3
mg/L
5 CCR 1002-8, Sect. 3.8.6, Region 3,
Segment 11
Yes/Yes
Iron (Total)
1.0
mg/L
5 CCR 1002-8, Sect. 3.8.6, Region 3,
Segment 2 protects aquatic life from
chronic toxicity.
Yes/Yes
Lead
Manganese (Soluble)
0.0013
0.050
mg/L
mg/L
5 CCR 1002-8, Sect. 3.8.6, Region 3,
Segment 11
Yes/Yes
Yes/Yes
o
<^>
H*
CO
cs
¦o
-------
TABLE B-3 (cont.)
COLORADO ARARS
CONTAMINANT-SPECIFIC ARARs WATER QUALITY LIMITED
Contaminant
Colorado
Contaminant-Specific
ARARb
Units
Applicable/
Relevant and
Title and Section of State Standard Appropriate
Comments
Manganese (Total)
1.0
mg/L
5 CCR 1002-8, Sect. 3.8.6, Region 3,
Segment 11
Yes/Yes
Mercury
0.012
mg/L
Yes/Yes
Nickel
0.050
mg/L
Yes/Yes
Radium (226 + 228)
pCi/L
5 CCR 1003-1, Article 7
No/No Not identified as contaminant
of concern
Selenium
0.010
mg/L
5 CCR 1002-8, Sect. 3.8.6, Region 3,
Segment 11
5 CCR 1003-1, Article 5
Yes/Yes
Silver
0.0001
mg/L
5 CCR 1002-8, Sect. 3.8.6, Region 3,
Segments 2, 11, 13
Yes/Yes
Thallium
0.013
mg/L
No/No Not identified as contaminant
of concern
Uranium
40
pCi/L
5 CCR 1002-8, Sect. 3.8.5
No/No Not identified as contaminant
of concern
-------
TABLE B—3 (cont.)
COLORADO ARARs
CONTAMINANT-SPECIFIC ARARs WATER QUALITY LIMITED
Colorado Applicable/
Contaminant-Specific Relevant and
Contaminant ARARb Units Title and Section of State Standard Appropriate Comments
Zinc mg/L Yes/Yes
0.28 (CC)
0.5 (NCC)
a standard is hardness dependent. Value is for hardness of 50 mg/L.
k Standards apply to surface water at a compliance point, downstream of mixing zone for effluent and receiving water.
-------
TABLE B-3
COLORADO ARARs
LOGATICN SPECIFIC ARARs - DISCHARGE THEA3WENT
Title and Section
of State Standard
Description
Applicable/Relevant
and Appropriate
Ccmnait
Colorado Water Quality
Control Act Sections
25-8-202 and 25-8-702
Procedural Regulations
for Site Applications
for Domestic Wastewater
Treatment Works, 5 OCR
1002-12, Sections 2.2.3,
2.2.4 and 2.2.5
Requires Water Quality Control Division
approval of the locations of wastewater
treatment facilities, before coranaicing
construction.
Establishes broad siting criteria
relative to floodplains and natural
hazards. Describes review procedure and
decision criteria; sumarizes
information and data requirements
No/Yes
No/Yes
Applicable to domestic waste-
water plants, but relevant aid
appropriate to industrial waste-
water plants
Relevant and appropriate to
treatment works site as a whole
Colorado Hazardous Waste
Management Regulations,
6 OCR 1007-3, Parts 260,
261, 262.11
Colorado Hazardous Waste
Act, Sections 25-15-101,
203, 208, 302
Requirements for siting
of Hazardous Waste
Disposal Sites. 6 OCR
1007-2, Sections 2.1,
2.2, 2.4.1, 2.5.1, 2.5.3
and 2.5.6
Defines hazardous solid wastes, requires
waste characterization
Establishes broad siting criteria and
site evaluation procedures for
individual storage or disposal units
(i.e. impoundments, landfills)
Geologic/Hydrologic conditions must
assure waste isolation from exposure
pathways from 1000 years. Siting mist
assure short and long term protection of
human health and environment.
No/Yes
No/Yes
No/No
Critical for determining siting
requirements
Relevant and appropriate if
waste characterization is
hazardous and cnsite disposal is
proposed. This is not
anticipated. Requires
consideration of local land uses
No disposal site is plamed.
O
O
M-
03
-------
TABLE B-3 (cent.)
OOUCRADO ARARs
LOCATION SPECIFIC ARARs - DISCHARGE TREA3WENT
Title and Section
of State Standard
Description
Applicable/Relevant
and Appropriate
Garment
Colorado Hazardous Vaste
Managemait Regulations,
6 CCR 10070-3, Part 260,
Subpart A and 264.18
Colorado Solid Wastes
Disposal Sites and
Facilities Act, Sections
30-20-101, 104, 110
Regulations Pertaining
to Solid Vaste Disposal
Sites and Facilities, 6
OCR 1007-2, Sections
1.1, 1.2, 1.3.2, 2.1.1,
4.1, 6.1
Regulations Pertaining
to Domestic Sewage
Sludge, 5 OCR 1003-7,
Sections 7 arid 8
Colorado State
Historical Society,
Sections 24-80-201, 202,
211; Sections
24-801-101, 102, 103,
104, 108
Siting is restricted in vicinity of
recent faulting. No hazardous vaste
disposal can occur in a 100 year flood-
plain. Disposal into or below surface
rater and ground rater is prohibited.
Establishes broad siting criteria and
site evaluation procedures for
individual storage and disposal units
(i.e., impouirihnents, landfills)
Siting must maximize wind protection and
minimize upstream drainage area. No
solid waste disposal can occur in a 100
year floodplain. Disposal into or below
surface rater and ground water is
prohibited. Impoundment design is
controlled by a site's location in
relation to the upper-most aquifer and
by water quality in that aquifer.
Siting restrictions for land application
of domestic wastewater sludges based on
soil texture, proximity to surface water
and proximity to diversions for public
water systems.
Sites within state or federal historic
preservation areas will be required to
preserve historic character.
No/No
No/Yes
No/No
No/No
No/Yes
No hazardous waste disposal is
contenplated.
Relevant and appropriate if
waste characterization is non-
hazardous, and onsite disposal
is proposed.
No hazardous waste disposal site
is contemplated.
No land application of domestic
wastewater sludges is
contenplated.
A Memorandun of Agreement has
beai initiated.
O
®
OO
-a
-------
cc Work2/R0D/130
TABLE B-3
OOLCRADO ARARs
ACnCN-SEBdFIC ARARs - DISCHARGE TREATMENT
Title and Section
of State Standard
Description
Applicable/Relevant
and Appropriate
Cement
Colorado Water Quality Control
Act, Sections 25-8-101, 102,
103, 203, 204, 205, 304, 501,
502, 503, 601, 602, 603, 605,
606 , 607, 608, 609, 610
Colorado Wildlife, Sections
33-1-101, 102, 103, 104, 105,
106, 107, 108, 109, 110, 115,
120
Establishes state policies toward rater No/Yes
quality protection. Defines terms.
Authorizes regulations and lists
information, data monitoring and operational
requirements that must be included.
Describes enforcement procedures.
Establishes borad program for protecting No/Yes
wildlife, and suimarizes broad protective
criteria.
Promulgated guidance on program
goals, policies, regulations.
Relevant and appropriate as reason
to treat discharges.
Colorado Department of Health
Administration, Sections
25-1-101, 102, 103, 107(e),
(s), (t), 108, 109, 110, 114,
114.1
Establishes safe drinking water authorities
for the state.
No/Yes
Procedural Regulations for
Site Applications for Domestic
Wastewater Treatment Works, 5
OCR 1002-12, Sections 2.2.3,
2.2.4, 2.2.5
Basic Standards and
Methodologies, 5 OCR 1002-8,
Sections 3.1.2, 3.1.3, 3.1.4,
3.1.5, 3.1.8, 3.1.9, 3.1.10,
3.1.11, 3.1.13, 3.1.14, 3.8.2,
3.8.3, 3.8.4
Describes review procedures and decision No/Yes
criteria. Suimarizes information, data
monitoring, and reporting requirements.
Establishes performance standards and No/Yes
procedures for applying contaminant specific
ARARs.
Applies to treatment facility site
as a whole
O
o
H*
CO
-a
t\T-
-------
TABLE B-3 (Continued)
COLORADO ARARs
ACrrCN-SEECIFIC ARARs - DISCHARGE TOEA3MENT
Title and Section
of State Standard
Description
Applicable/Relevant
and Appropriate
Comnent
Regulations Prohibiting the
Discharge of Certain
Wastewaters to Storm Sewers
and Prohibiting Certain
Connections to Storm Sewers, 5
OCR 1007-2, Sections 5.1.1 and
5.1.2
Prohibits industrial discharges to storm
sewers without permits.
No/No
State Discharge Permit System
Regulations, 5 COR 1002-2,
Sections 6.2, 6.3, 6.5, 6.6,
6.9, 6.10, 6.12, 6.14
Colorado Hazardous Waste
Management Regulations, 6 OCR
1007-3, Parts 260, 261, 262.11
Colorado Solid Waste Disposal
Sites and Facilities Act,
Sections 101, 104, 109, 110,
113, 114
Describes review procedures and decision No/Yes
critieria. Sumnarizes information, data
monitoring and reporting requiremaits.
Defines hazardous solid wastes, requires No/Yes
waste characterization.
Establishes broad design criteria and No/Yes
minimun standards for operating individual
storage and disposal units. Describes
enforcement procedures.
Refer to NPDES in Table B-2
Critical for determining waste
handling requirements.
O
O
-------
TABLE B-3 (Continued)
OOLCRADO ARARs
ACTICN-SPECIFIC ARARs - DISCHARGE TREA3MENT
Title and Section
of State Standard
Description
Applicable/Relevant
and Appropriate
Carment
Regulations Pertaining to
Solid Vastes Disposal Sites
and Facilities, 6 OCR 1007-2,
Sections 1.1, 1.2, 1.3.2,
1.3.3, 2.1.1, 2.1.2, 2.1.3,
2.1.4, 2.2.1, 2.2.2, 2.2.3,
2.2.4, 2.2.5, 2.2.9, 2.2.10,
2.2.11, 2.2.12, 2.2.13, 2.3,
2.4.3, 2.4.5, 2.4.6, 3.1.2,
4.2, 4.3, 4.4, 4.5, 4.6, 4.7,
4.8, 6.2, 6.3, 6.4, 6.5, 6.6,
6.7, 6.8, 6.9
Colorado Hazardous Waste Act,
Sections 25-15-101, 102,
200.1, 200.2, 200.3, 202, 203,
208, 210, 302, 308, 309, 310
Requirements for Siting of
Hazardous Waste Disposal
Sites, 6 OCR 1007-2, Sections
2.1, 2.2, 2.3.2, 2.3.3, 2.3.4,
2.3.5, 2.4, 2.5.1, 2.5.2,
2.5.4, 2.5.5
Colorado Hazardous Waste
Management Regulations, 6 CCS
1007-3, Parts 99; 100.11,
100.12, 100.40, 100.41,
262.12, 262.34, 262.40,
262.43; 264, Subparts A, B, C,
D, E, F, G, I, J, K, L, M, N
Describes specific design criteria and
minimum standards for operating individual
storage and disposal units. Smmarizes
information, data, monitoring and reporting
requirements.
No/Yes
Establishes broad design criteria and
minimum standards for operating individual
storage and disposal units. Sunmarizes
enforcement procedures.
Establishes specific design criteria for
individual storage and disposal units.
Sunmarizes information, data, monitoring and
reporting requirements.
Establishes specific design criteria and
minimum standards for operating individual
storage or disposal units. Sunmarizes
information data, monitoring and reporting
requirements.
No/Yes
Relevant and appropriate if vastes
characterized as hazardous, and if
on-site disposal is considered.
This is not anticipated.
No/No
No/Yes
Relevant and appropriate for on-site
disposal, and for on-site storage
prior to off-site shipment, not for
generators.
®
®
H*
CO
-J
-------
TABLE B-3 (Continued)
COLORADO ARARs
ACTICN-SPBCEFIC ARARs - DISCHARGE TREATMENT
Title and Section Applicable/Relevant
of State Standard Description and Appropriate Carment
Colorado Basic Standards for
Ground Water, 5 OCR 1002-8,
Sections 3.11.0 to 3.11.9
Colorado Hazardous Waste
Management Regulations 6 OCR
1007-3, Parts 262, 263, 264,
Subparts C, D and 264.16.
Public Utilities Law, Sections
40-1-101, 102, 103; 40-2-101,
108, 110.5, 116; 40-2.1-101,
102, 103, 104, 105, 106;
40-11-101, 102, 106, 107, 108,
109, 110, 111, 112, 113, 114,
115, 116, 117
Establishes a system for classifying ground
water and adopting water quality standards
to protect existing and potential beneficial
uses.
Establishes additional reporting
requirements for off-site shipment.
No/No
No/Yes
No/Yes
Hie Section 3.11.0 framework, site-
specific classifications and
standards may be applied when
authority to inplement exists in any
applicable regulatory program (e.g.,
Solid Waste Regulations).
Relevant and appropriate for
generators who accunulate (but do
not store), in containers and tanks,
and for transporters.
Rules and Regulations
Governing the Shipping of
Hazardous Wastes Within
Colorado, 4 OCR 723-17, HMS
1-9
Establishes specific requirements for the
shipping of hazardous materials.
No/Yes Hazardous wastes are a subset of
hazardous materials. Shipping of
hazardous materials is not
anticipated.
O
O
H4,
CO
-a
-------
TABLE B-3 (Continued)
OOLCRADO ARARs
ACITCN-SPBCXFTC ARARs - DISCHARGE TREATMENT
Title and Section
of State Standard
Description
Applicable/Relevant
and Appropriate
eminent
Rules and Regulations
Governing the Transportation
of Hazardous Materials Within
Colorado, 4 OCR 723-18, HMT
1-9
Colorado Air Quality Control
Act, Sections 25-7-101, 102,
105, 106, 107, 108, 109, 110,
114, 117
Colorado Air Quality Control
Regulations, Cormon Provisions
(5 OCR 1001-2) and Regulation
1 (5 OCR 1001-3), Subsections,
I, H(A)(1) and m(D),
Regulations 8 (5 OCR 1001-10);
Ambient Air Standards (5 OCR
1001-14); AAS-1.1
Colorado Noise Abatement
Statute, Sections 25-12-101,
102, 103, 104, 105, 106, 107,
108
Colorado Wildlife Enforcement
and Penalties, Sections
33-6-101, 102, 103, 104, 105,
108, 109, 110, 111, 113, 114,
116, 117, 119, 120, 124, 126,
128, 129, 130
Establishes specific requirements for the No/Yes
transportation of hazardous materials,
especially regarding labelling and
placarding.
Establishes broad standards for air quality No/Yes
protection
Establishes standards for controlling No/Yes
fugitive particulate emissions and air
toxics. Defines terms.
Establishes standards for controlling noise No/Yes
Prohibits specific actions as ways to
protect wildlife.
No/Yes
Hazardous wastes are a subset of
hazardous materials. Supping of
hazardous materials is not
anticipated.
Relevant and appropriate during
construction activities.
Relevant and appropriate during
construction activities.
Relevant and appropriate for
protecting wildlife near the site
during construction activities.
O
o
CO
-a
as
-------
TABLE B-3 (Continued)
oolcrado mm
fcmm-smmc mm - discharge tm&mnt
Title and Section Applicable/Relevant
of State Standard Description and Appropriate Gomnent
Wildlife CGBndssian Establishes specific requirements for No/Yes
Regulations, 2 OCR 406-0, protection of wildlife.
Articles I, m, IV, V, VI,
vn, vm, ix, x, n
Colorado Abatement of Public No/No
Nuisance Act, Sections
16-13-301, 302, 305, 307, 308,
309(4), 312
Regulations Pertaining to No/No
Domestic Sewage Sludge, 5 OCR
103-7, Sections 1-6, 9-14
(Laid Application)
-------
APPENDIX C
INDEX TO THE ADMINISTRATIVE RECORD
-------
s*iv
2K
0011379
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
% «>o^
ONE DENVER PLACE — 999 18TH STREET — SUITE 1300
REGION VIII
ER PLACE — 999 18TH S
DENVER, COLORADO 80202-2413
August 28, 1987
To: Residents and Other Interested Parties
The Administrative Record (AR), a compilation of all significant documents
used in making decisions for the Clear Creek/Central City Superfund site, is
now available. Because of the volume of materials, the full AR has been
placed in the information files at the following addresses:
Gilpin County Courthouse
203 Eureka
Central City, CO 80427
(303) 569-3251
Hours: Mon.-Fri. 8:00-4:30
U.S. EPA Library
999 18th Street
Denver, CO 80202
(303) 293-1444
Hours: Mon.-Fri. 8:00-4:00
An index of the AR is available at all five information files, including those
listed below:
Idaho Springs
City Hall
1711 Miner Street
Idaho Springs, CO 80452
(303) 567-4421
Hours: Mon.-Fri. 8:00-5:00
Idaho Springs
Public Library
219 14th Street
Idaho Springs, CO 80452
(303) 567-2020
Hours: Mon.,Tues.,Thurs.
1:00-7:00
Wed.,Fri. 9:00-5:00
Saturday 10:00-3:00
Golden Public
Library
923 10th Street
Golden, CO 80401
(303) 279-4585
Hours: Mon.-Thurs.
10:00-9:00
Fri.-Sat. 10:00-5:00
Sunday 12:00-5:00
The purpose of the AR is to provide complete documentation of the process and
studies prepared for the site. We encourage you to review these materials.
If you have any questions about the materials, please give me or Walter Sandza
a call. You can reach Walter Sandza at (303) 293-1519. I can be reached at
1-800-332-3321 (toll free) or (303) 293-1699.
jiincerelv.
To
Community Relations Coordinator
-------
csncity
0011380
CENTRAL CITY/CLEAR CREEK ADMINISTRATIVE RECORD
CENTRAL CITY/CLEAR CREEK REMEDIAL ACTION DOCUMENTS
1OOOO1
December 1, 1967
Pages: 150
Report
Pollution/aquatics S. Plat Basin
By: U. S. Dept. of Interior
To: unknown
100002
December 1, 1967
Pages: 32
Rpt Ado
Pollution/aquatics S. Plat Basin
By: U. S. Dept. of Interior
To: unknown
100003
December 1, 1975
Pages: S3
Report
Biota ?< W. Quality S. Plat River
Bluestein 2< Hendricks
By: Unknown
100004
August 1, 1978
Pages: 4
Data
CC fish soecies counts near metro
By: Colo. Div. o-f Wildlife
To: unknown
100005
July 30, 1982
Pages: 41
Report
EPA fit team report on NCC drainage
By: Donna Toeroek, Fred C. Hart Associates, Inc.
To: Keith 0. Schwab (EPA)
-------
cenci tv
00113S1
100006
January 18, 19e3
Pages: 4
EPA action memo proceed w/RI/FS
From; William H. Hedeman (EPA)
To: Rita li. Lavelle (EPA)
100007
February S, 1983
Pages; 48
Report
Black %>. Veatch Rem. Plan to EPA
By; Black and Veatch
To: EPA
100008
June 3, 19S3
Pages: 20
Mcintosh title search and tail ID
From: James Mcintosh
To; Ecology and Environment
100009
Sentember 15, 19B3
Pages: 40
Reoort
CH2M Hill work olan and assign.
By; CH2M Hill
To; unknown
100010
September 19, 1983
Pages: 107
Letter
Colo. Dept. Health comments on CC
From: Various authors
To: Various addressees
100011
June 28, 1984
Pages; 4
Co. mined land reclam on CC RI/FS
By; David Holm (Mined Land Reclaim Div.)
To: John Hardawav
-------
cencitv
0011382
100012
February 25, 1985
Pages: 50
Report
CH2M Hill final work plan RI/FS
By: unknown
Tos unknown
100013
May 31, 1985
Pages: 78
Report
Draft Work Plan for CC RI/FS
By: Robert L. 01 sen (CDM)
To: Judith Wong and Walter Sandza (EPA)
100014
June 6, 1985
Pages: 167
(POP)
Project Operations Plan V. 2 orgs
Bv: CDM
To: EPA
100015
June 6, 1985
Pages: 101
(POP)
Project Operations Plan V. 1 orgs
By; CDM
To: unknown
100016
June 19, 1985
Pages: 13
Letter
Gormley Wk. Plan Recommend on CC
From: James J. Gusek Z>. John T. Gorml ey
To: Roger 01 sen (CDM)
100017
June 24, 1985
Pages: 133
Report
Final Work Plan for CC RI/FS V. 1
By: CDM
To; EPA
-------
cartel tv
0011383
1000 i s
October 1, 1965
Pages: 15
Data
STS Soil Boring Logs, Tail. Tun
By: J. LeClaire (CDM)
100019
October 1, 1985
Pages: 41
Data
Sormley Drilling Borehole Logs CC
By: Gormlev
To: CDM
100020
October 14, 1985
Pages: •-¦2
Mi sc.
Aquatic Ecology Info. Notes Data
Bv; CDM
To: unknown
100021
November, 1985
Pages: 6
Dat s
Ground water results
By: unknown
To: unknown
100022
December 1, 1985
Pages: 4
Figures
Figures for super-fund fact sheet
By: unknown
To: unknown
100023
December 1, 1985
Pages: 4
Fact sheet
Fuoertund proaram -fact sheet CC
By: EPA
To: unknown
-------
certci tv
00113gj
100024
February 4, 1986
Pages: 1
Data
Geotech Borehole Coords
Bv; unknown
Toj unknown
100025
April 22, 1986
Pages: 6
Data
CC Creek Census and Stocking Info
By; unknown
To; unknown
100026
April 23, 1986
Pages: 19
Report
Final Health & Safety PI an Approv
Bv: unknown
To: unknown
100027
May 29, 1986
Pages: 2
CDM to Dept. Health on Water Stds
From: John K. Hopkins (CDM)
To: Thomas Looby (CO Dept. of Health)
100029
June 11, 1986
Pages: 2
Minutes
CDM interview Sol den W. Treatment
By: Qlsen ?•< Hopkins (CDM)
To: Clear Creek/Central City files
100029
June 21, 1986
Pages: 9
Report
Report on Value of Gregory Tail.
By: W. Rex Bull & Thomas R. Wildeman
To: CDM
-------
cenci ty
0011385
100030
July 1, 19S6
Pages: 4
Fact Sheet
Super-fund -fact sheet Gregory tail
By: unknown
100031
July 1, 1986
Pages: 62
ReDort
Bormlev source control investigs.
By: Gormley
To: CDM
100032
Julv 10, 1986
Pages: 23
Ltr Rot
Low Flows CC: Co. Dept. Health
By: Rich Horstmann (CO Dept. o-f Health)
To: John HoDkins (CDM)
100033
August 1. 1986
Pages: 24
Reoort
Big 5 Pass. Treat. Design 3< Cost
By: E. A. Howard (CO School o-f Mines)
To: CDM
100034
August 1, 1986
Pages: 183
Report
Gormley Geotech Investigations
By: James J. Gusek (Gormley)
To: Roger 01 sen (CDM)
100035
August 1, 1986
Pages: 18
Appendix
Gormley Geotech
By: James J. Gusek (Gormley)
To: Roger Olsen (CDM)
-------
csncitv
0011386
100036
August 19, 1986
Pages: 2
EPA memo, RCRA Regs at mine sites
By: Henrv L. Lorgest II (EPA)
To; Waste Management Dv Dir.
100037
November 1, 19S6
Pages: 222
Validated lab data pkgs (V> 2)
Bv: COM
100038
November 1, 1986
Pages: 121
Validated lab data okas 4)
Bv: CDM
100039
November 1, 1986
Pages: 108
Validated lab data okgs (V, 1C)
By: CDM
100040
November 1, 1986
Pages: 175
Validated lab data pkgs (V. 1A)
By: CDM
100041
November 1, 1986
Pages: 301
Validated lab data pkas
-------
cencity
100043
November 1, 1966
Pages: 197
Validated lab data pkgs (V. 10)
By: CDM
100044
November 1, 1986
Pages: 192
Validated lab data okgs (V. 5)
Bv: CDM
100045
November 1, 1986
Pages: 236
Validated lab data pkgs (V. 8)
By: CDM
100046
November 1, 1986
Pages: 229
Validated lab data pkgs (V. IB)
Bv: CDM
100047
November 1, 1986
Pages: 280
Validated lab data pkgs (V. 6)
Bv: CDM
100048
November 1, 1986
Pages: 189
Validated lab data pkgs (V. 9)
By: CDM
100049
December 15, 1986
Pages: 2
Mi nutes
Minutes risk assessment meeting
By: John HoDkins (CDM)
To: Attendees o-f meeting
-------
cenci tv
0011388
100050
December 16, 1986
Pages: 12
Letter
ICF/Clement water quality summs.
From: Patricia Billing (CDM)
To: Paul Chrystowski (ICF)
100051
December 23, 1986
F'aaes: 2
EPA to CO Deot. o-f Health on ARARS
From: Robert L. Duprey (EPA)
To: Thomas Looby (CO Deot. o-f Health)
100052
February 10. 1987
Pages: 4
EPA on Historic Memo o-f Agreement
From: Rick Claggett (Hist. Preserv. Q-f-fi cer)
To: Addressees
100053
March 2, 1987
Pages: 3
Memo o-f Agreement
EPA, CO Hist. Soc. and the Adv. Council on Hist. Preservation
From: unknown
To: unknown
100054
March 10, 1987
Pages: 1
1 tr. re: Memo of agreement
From: Robert Fink (Council on Hist. F'reser)
To: Sharon L. Kercher (EPA)
100055
April 1, 1987
Pages: 589
Report
Dra-ft Remedial Invest. V. 1 Text
Bv: Roaer L. Qlsen (CDM)
To: EPA
-------
c en city
0011389
100056
April 1, 1987
Pages: 732
ReDort
Draft Remedial Invest. V 2 Text
By: Roger L. Qlsen (CDM)
To: EPA
100057
April 7, 1987
Pages: 103
Report
Arao Tunnel Water Treatab. Study
From: Resource Tech. Group
To: CDM
100058
Apri1 7, 1987
Pages:
EPA Release on CC well water surv
By: EPA
100059
Mav 22, 1987
Pages: 1
Klusman Scientific comments on RI
From: Ronald W. Klusman (CO School of Mines)
To: Roger 01 sen (CDM)
100060
Mav 27, 1987
Pages: 7
EPA Ltr to CO Hist Soc on Big 5
From: Walter Standza
-------
cencitv
0011390
100062
June 4, 1987
Pages: 19
EPA ltr 2 to CO Hist Soc on Big 5
From; Walter Standza
-------
cenci ty
001131)1
10006S
June 29, 1987
Pages: 15
Report
Army Corps Eng. comments on RI/FS
By: S. L. Carlock (Dept. of Army)
To: John Hopkins (CDM)
100069
July 2, 1987
Pages: 34
Ltr & Refs
Maxwell comments on RI/FS S< Arqo
From: James N. Maxwell
To: Walter Standza (EPA)
100070
July 3, 1987
Pages: 2
Letter
Idaho Springs comments on RI/FS
From: James Reed (Mayor of Idaho Spr.)
To: Walter Stand2a. (EPA)
100071
July 6, 1987
Pages: 1
Letter
CC metal min. assn. on RI/FS
From: Patricia C. Mosch (Clear Creek Co. Metal Mining
Assoc.)
To: Walter Standza (EPA)
100072
July 7, 1987
Pages: 2
Letter
Attys. -for Blakes on RI/FS
From: Jerald J. Dewitt
To: Walter Standza and Jane ~. Russo (EPA)
100073
July 7, 1987
Pages: 2
Letter
Central City protest on RI/FS
From: Bruce Schmalz (City of Central City)
To: Walter Standza and Jane 0. Russo (EPA)
-------
cencitv
0011392
100074
July 8, 1987
Pages; 1
Historic Preserv. reoly on Big 5
From: Robert Fink (Ad. Council on Hist. Pres.)
Tos Walter Standsa (EPA)
100075
July 10. 198/
Pages: 1
Letter
Trout unltd response to CC RI/FS
From: Kent Fi shman (Trout Unltd)
To: Jane Russo (EPA)
100074s
July 23, 1987
Pages: 67
Ret s
Metal. Acid effects on Strm. life
By: Various authors
To: unknown
100077
July 27, 1987
Pages: 16
Letter
CO Deot. of Health reply on draft RT/FS CC ST IN
From: Ned Noack (Deot. of Health)
To: Jay Si 1 vernale (EPA)
100078
October 11, 1984
Pages: 2
Letter with mail control schedule
Information regarding Argo Tunnel
From: Cynthia S. Leap, Adolph Coors Co.
To: Freedom of Information Act Officer, EPA
100079
September 27, 1985
Pages: 6
Letter with attached forms
Investigation in the vicinities of Idaho Springs and Central City
for acid mine drainage and tailings
From; J. William Geise, EPA
To: The residents
-------
cenci tv
001131)3
100080
October 8, 1985
Pages: 2
Letter
Central City/Clear Creek CERCLA site; request -for access
From: J. William Geise, Jr., EPA
To: George Groves, Raquette Real Estate
100081
October 29, 19B5
Pages: 2
Letter
Central City/Clear Creek CERCLA site; request -for access
From: Stephen P. Cherry,
To: George Groves, Raquette Real Estate
100032
October 31, 1985
Pages: 6
Letter
fleeting on ARAR's inoperable units Clear Creek/Central City RI/FS
From: Roger L. 01 sen, CDM
To: Walter Stanza and Sandra Moreno, EPA
100083
November 11, 1985
Pages: 6
Fact Sheet
Clear Creek/Central City site
By: EPA
100084
November 7, 1985
Pages: 5
Form
USEF'A permission -form -for access to properties concerning the
Clear Creek/Central City hazardous waste site investigations
From: EPA
To: various property owners
100085
November 13, 1985
Pages: 1
Meeting Report
Clear Creek Countv Metal Mining Assn.
From: unknown
To: unknown
-------
cenci ty
0011394
100085A
Apri1 11, 1986
Pages: 38
Report
Preliminary Screening Analysis, Gregory Incline S<
Tailings/Expedited Response
From: Camp Dresser 8< McKee Inc.
To: EPA
100086
May 12. 1986
Pages: 15
Memorandum
Meeting with Colorado Historical Society May 12, 1986
From: Mark Switak, CDM
To: Walter Standza, EPA
100087
June 13, 1986
Pages: 66
ReDort
Engineering Evaluation Cost Analysis o-f Alternatives, Gregory
Incline Tailings Expedited Response
From: Camp Dresser ?< McKee
To: EPA
100088
November 18, 1986
Pages: 14
Memorandum
November 17, 1986 meeting summary and action item
From: Roger 01 sen, CDM
To: Walter Standza, EPA
100089
December 5, 1986
Pages: 2
Memorandum
Agenda -for Clear Creek/Central City RI/FS risk assessment meeting
From: Roger Olsen, CDM
To: Waiter Standza, Sandra Moreno, Jim Baker and Ned
Noack
-------
cenci ty
0011305
100090
December 16, 1986
Pages: 1
Record o-f Communication
The Nederland Mountaineer (a newspaper)
From: Barbara Lawlor
To: Jane Russo
100091
December 22, 1986
Pages: 1
Memorandum
Meeting to discuss ARARs for the Clear Creek/Central City site
From: Patricia Billig, CDM
To: Distribution
100092
February 19, 1987
Pages: 2
Letter
Clear Creek/Central City RI/FS status
From: CDM
To: Sandra Moreno, EPA
100093
February 19, 1987
Pages: 27
Letter
Bite access and site use Big 5 tunnel. Clear Creek/Central City
RI/FS
From: Roger L. Qlsen, CDM
To: Sandra Moreno, EPA
100094
February 25, 1987
Pages: 16
Memorandum
Clear Creek/Central City FS, February 19, 1987 progress report
From: R. L. 01 sen and J. K. Hopkins, CDM
To: Walter Standza, EPA
100095
March 4, 1987
Pages: 5
Letter
Gregory tailings Central City/Clear Creek, CERCLA site
From: Jerald J. Devitt, o-f Devitt and Weiszmann
To: Robert L. Duprey, EPA
-------
cenc itv
0011396
100096
March 4, 1987
Pages: 4
Letter
Gregory tailings Central
From: Jerald J. Devitt,
To: Sandra R. Moreno,
Citv/Clear Creek, CERCLA site
of Devitt and Weiszmann
EPA
100097
March 6, 1987
Pages: 2
Letter
Enclosure of -fact sheets -for the Gregory tailings operable unit
of the Clear Creek/Central City National priorities list site
From: Sharon L. Kercher, EPA
To: Steve Smith, Colorado Second Congressional District
Office
100093
March 10, 1987
Pages: 1
Agenda
Meeting of the Citv of Black Hawk
100099
March 25, 1987
Pages: 1
Consent Form
Clear Creek/Central City CERCLA site, Gregory tailings
From: Marko Lah and Joanne Lah
To: EPA
100100
March 26, 1987
Pages: 1
Consent Form
Clear Creek/Central City CERCLA site, Gregory tailings
From: Kevin J. Roche
To: EPA
100101
March 25, 1987
Pages: 1
Consent form
Clear Creek/Central Citv CERCLA site, Gregory tailings
From: David G. Spellman
To: EPA
-------
cenci tv
0011307
100102
March 27. 1987
Pages: 2
Letter
The City Council meeting o-f March 10, 1987
Froras Sharon L. K.ercher, EPA
To: Bill Lorenz, Mayor o-f Black Hawk
100103
March 27, 1987
Pages: 2
Letter
The Big 5 tunnel site access Clear Creek/Central City RI/FS site
From: John Hopkins, CDM
To: Sandra Moreno, EPA
100104
March 30, 1987
Pages: 3
Memorandum
Clear Creek/Central City FS March 1987 progress report
From: R. L. 01 sen/J. K. Hopkins
To: Walter Standza, EPA
100105
March 31, 1967
Pages: 2
Lett
Issuance o-f the utility permit to highway right-of-way near mile
post 240
From: John Hopkins, CDM
To: P. R. McOllough, Colorado Dept. of Hwys.
100106
March 31, 1987
Pages: 3
Letter
Gregory tailings, Central City/Clear Creek CERCLA site
From: Jerald J. Devitt, Devitt tt Wei szfliann
To: Robert L. Duprey, EPA
-------
cencitv
0011398
100107
April 1, 1987
Pages: 1
Sample letter
Agreement with Norman R. Blake and Mildred L. Blake regarding
utilisation of property owned by the Blake's and located between
Selack "St. and Gregory Mill site
From: Norman R. and Mildred L. Blake
To: Harold W. Zarling, Riedel Environmental Services Inc.
10010b
April 2, 1987
Pages: 1
Letter
Verbal consent to access the mill tailings on adjacent property
from Norman Blake
From: Sharon L. Kercher
To: Harold Zarling, Riedel Environmental Services Inc.
100109
April 6, 1987
Pages: 3
Memorandum
Big 5 tunnel passive treatment pilot land
From: John Hopkins, CDM
To: Walter Sandsa and Sandra Moreno, EPA
100110
April 13, 1987
Pages: 1
Letter
Gregory tailings, Central City/Clear Creek CERCLA site
From: Jerald J. Devitt, Devitt and Weiszmann
To: Sharon Kercher, EPA
100111
April 13, 1987
Pages: 4
Letter
Decision not to place riprap material along the bank of the creek
behind property
From: Sharon Kercher, EPA
To: Mr. and Mrs. Marko Lah
-------
cencity
0011309
100112
April 16, 1987
Pages: 3
Letter
Clear Creek/Central City site request -for access
From: Sandra R. Moreno, EPA
To: The Honorable Bill Lorenz, Mayor City of Black Hawk
100113
April 20, 1987
Pages: 3
Letter
Clear Creek/Central City site request for access
From: Sandra R. Moreno, EPA
To: Kermit's Restaurant
100114
April 24, 1987
Pages: 3
Memorandum
Big 5 tunnel ownership Clear Creek/Central City
From: John Hopkins, CDM
To: Sandra Moreno, EPA
100115
April 29, 1987
Pages: 1
Letter
Papers on passive treatment technology
From: John Hopkins, CDM
To: Jim Reid, Mayor City of Idaho Springs
100116
April 30, 1987
Pages: 1
Letter
Central City/CIear Creek CERCLA site: request for access
From: Sandra R. Moreno, EPA
To: George Sroves, Raquett Real Estate
100117
May 1, 1987
Access Agreement
Construction of a passive treatment pilot plant structure at the
Big 5 tunnel
From: George Groves
To: EPA
-------
cenci tv
0011400
100113
May 14, 1987
Pages: 3
Letter
Geotechnical drilling. Big 5 tunnel waste rock
From: J. William Geise
To: A1 Hoyl, Los Lagos Ranch
100119
June 1987
Pages: 2
Fact Sheet
Clear Creek/Central City super-fund site
By: EPA
100120
June 10, 1987
Pages: 2
Letter
Copy of reauested statute
From: Sandra R. Moreno
To: Alfred G. Hovl, Los Lagos Ranch
100121
June 11, 1987
Pages: 2
Gregory tailings. Central City/Clear Creek CERCLA site
From: Jerald J. Deyitt, Devitt and Weissmann
To: Sharon Kercher and Walter Sandsa, EPA
100122
June 12, 1987
Pages: 1
Access Agreement
EPA authority to enter upon property
From: Alfred G. Hoyl
To: EPA
100123
June 16, 1987
Pages: 3
Letter
Gregory tailings, Central City/CIear Creek CERCLA site request
for information and documents
From: J. William Geise, EPA
To: Jerald J. Devitt, Devitt and Weiszmann
-------
cencitv
0011401
100124
•July 7. 1987
Pages: 6
Letter
Draft feasibility study report, Clear Creek/Central City site
draft remedial investigation report
From: Bruce Schmaltz, Mayor of Central City
To: Walter Standza and Jane 0. Russo, EPA
100125
July 3, 1937
Pages: 1
Record of communication
Central City/Clear Creek NPL site
From: Bill Seise
To: Norm Blake
100126
July 15, 1987
Pages: 1
Record of communication
Meeting at Central City with Mayor Schmaltz 7/15/B7
From: C. Jav Silvernail
To: Walter Standza, EPA
100127
July 16, 1987
Pages: 3
Record of communication ooerable unit schedule
Blow off control
From: Walter Standza, EPA
To: C. Jay Silvernail
100128
July 20, 1987
Pages: 1
Record of communication
Meeting at Central City with Mayor Schmaltz and Aldermen
From: Jane Russo
To: C. Jay Silvernail
100129
July 21, 1987
Pages: 1
Record of communication
Cadmiun and drinking water of residences in Clear Creek
From: C. Jay Silvernail
To: Walter Standza
-------
cenci ty
OOI140
100130
July 21. 19S7
Pages: 1
Letter
The transmittal of revised design -for the -fence at the Big 5
tunnel Clear Creek
From: Walter Standza, EPA
To: Jay Yanz, Colorado Historical Society
100131
July 23, 1987
Pages: 1
Letter
Extension to the oubl ic comment -for Clear Creek super-fund project
From: J. William Geise, EPA
To: Jerald J. Devitt, Devitt and Weiszman
100132
Various dates -from April through July 1987
Pages: 11
Newscaper Articles
Central City/Clear Creek removal site o-f the Gregory tailings
From: various
To: general public
100133
Date unknown
Pages: 5
Site Plans
Gregory tailings
From: CDM
To: unknown
100134
Date unknown
Pages: 6
Report
Characteristics o-f contaminants
From: unknown
To: unknown
-------
cenci tv
0011403
100135
October 10, 1980
Pages: 5
Inter—Office communication
Test of water treatment Argo tunnel
Fromj Don Simpson and Dave Helm, CDH
To: Arden Wallum
100136
June 30, 1982
Pages: 5
Inter-Office communication
Argo tunnel and Gregory tailing pile
From; June Dreith
To: Superfund file
100137
Mav 31, 1983
Pages: 1
Inter-Office communication
Argo tunnel/Mav 28, 1983
From: Mary Cervera
To: Emergency response file
100133
October 21, 1985
Pages: 2
Letter
Technical advisory committee update Clear Creek/Central City
superfuntis site
From: Roger L. 01 sen, CDM
To: Ned Noack. Colo. Dept. of Health
100139
February 19, 1986
Paaes: 2
Letter
Technical* advisory committee update, Clear Creek/Central City
superfund site
From: Roger L. Olsen and Patricia R. Fuller, CDM
To: Ned Noack, Colo. Dept. of Health
-------
cenci tv
0011
100140
•June 19, 1986
Pages: 1
Intef—Office communication
Central City, RI, FS and ERA
From: Ned Noack, Colo. DeDt. of Health
To: Ken Mesch, Central City, CERCLA
100141
June 25, 1986
Pages: 2
Inter—Office communication
Central City ERA
From: Ned Noack, Colo. Dept. of Health
To: Ken Mesch, Central City, CERCLA file
100142
June 26, 1986
Pages: 1
Record of communication
Woodbury and Central City update
From: Ned Noack, Colorado Dept. of Health
To: Ken Mesch
100143
July 3, 1986
Pages: 1
Inter-Office communication
Argo tunnel complex
From: Gary Broetzman, CDH
To: Tom Looby
100144
September 29, 1986
Pages: 1
Letter
Management of superfund site cleanup
From: L. Russell Freeman of James L. Grant and Associates
To: Mr. Peter Kenney, Commission Chairman of Clear Creek
County
100145
November 11, 1986
Pages: 3
Record of communication
CDH/EPA superfund/Colorado Historical Society meeting 11/10/86
From: Ned N.
To: Ken M. and Central City file
-------
cenci ty
0011405
100146
January 20, 1987
Pages: 1
Letter
The Board of County Commissioners of Clear Creek County's
interest in the possibility o-f playing a primary role in the EPA
super-Fund cleanup activities
From: Peggy Stokstad, Peter Kennev and Joe Hruska, Board o-f
County Commissioners
To: Ned Noack, Colo. Dept. o-f Health
100147
February 13, 19B7
Pages: 1
Record o-f communication
Progress, Gregory Incline tailings ERA
From: Ned
To: Ken M., Central City CERCLA
100143
April 1987
Pages: 3
Tabl e
Prooosed schedule of deliverables
From: unknown
To: unknown
100149
April 27, 1987
Pages: 1
Record of communication
Domestic well efforts
From: Ned N.
To: Ken M., Central City CERCLA file
100150
June 15, 1987
Pages: 2
Memorandum
Clear Creek/Central City Colo. Remedial Investigation
From: Ellen Mangione and Sharon Norman
To: Ken Mesch
-------
cencitv 00114 06
100151
July 9, 1987
Pages: 5
Inter-Office communication
Preliminary comments draft RI, Clear Creek/Central City site
From: Ned Noack, Colo. Dept. of Health
To: Ken Mesch and Central City CERCLA file
100152
July 13, 1987
Pages: 2
Memorandum
Clear Creek/Central City feasibility study
From: Maureen Dudley
To: Ned Noack, Colo. Dept. of Health
100153
July 27, 1987
Pages: 5
Inter-Office communication
Clear Creek/Central City FS review
From: Ned Noack, Colo. Dept. of Health
To: Dan Scheppers and Ken Mesch
100154
Date unknown
Pages: 2
Questions and comments
Clear Creek Metal Miners Assn. meeting
From: unknown
To: unknown
100155
Date unknown
List
The technical advisory committee of the Clear Creek/Central City
site
From: unknown
To: unknown
-------
cenci tv
0011407
CENTRAL CITY/CLEAR CREEK REMOVAL ACTION DOCUMENTS
200001
November 18, 1965
Pages: 1
Letter
Mining Association cooperation
From: E. R. Lewandowski
Tos Jane 0. Russo
200002
December, 1985
Pages: 4
Fact Sheet
Mining and milling waste at the source of toxic metal
contamination
By: EPA
200003
April 11, 1986
Paqes: 37
Report
Preliminary screening analysis, Gregory Incline and Tailings,
expedited response action
By: CDM
200004
May 12, 1986
Pages; 2
Memorandum
Meeting with historical society
From: Mark Swatek, CDM
To: Walter Sandza, EPA
200005
June 13, 1986
Report
Engineering evaluation and cost analysis of alternative, Gregory
Incline and Tailings, expedited response action
From: Mark Swatek, Camp Dresser and McKee, Inc.
To: Walter Sandza, EPA
-------
certci tv
0011408
200006
July 1, 1986
Pages: 1
Report
Region 8 incident notification
From: Walter Sandza, Superfund remedial
To: unknown
200007
July, 1986
Pages: 4
Fact Sheet
EPA's proaress at the Clear Creek/Central City super-fund site
Bv: EPA
200008
Ju.lv, 1986
Pages: 188
Report
Geotechnical investigations, tailings and waste rock, Clear
Creek/Central City site
By; Gormley Consultants, Inc.
To: Camp Dresser McKee, Inc.
200009
July. 1936
Pages: 28
Appendix to Geotechnical investigations tailings and waste rock,
Clear Creek/Central City site
By: Gormley Consultants, Inc.
To: Camp Dresser McKee, Inc.
200010
September B, 1986
Pages: 3
News Release
Public comment. Announced by EPA
By: EPA
200011
July 14, 1986
Pages: 2
Letter
Comments on proposal for fifties mill tailing pond
From: Norman R. Blake
To: unknown
-------
cenci tv
0011409
200012
July 22, 1986
Pages: 2
Letter
Recommendations on the engineering evaluation and cost analysis
of alternative and preliminary screening analysis
From: Mona Dawkins, City o-f Black Hawke
To: Jane 0. Russo, EPA
200013
July 24, 1986
Pages: 2
Letter
Response to super-fund program -fact sheet
From: Marvin Thurber, Clear Creek Water User's Alliance
To: Jane 0. Russo, EPA
200014
August 5, 1966
Pages: 4
Memorandum
Review -from the agency -for toxic substances and disease registry
of soil samoles
From: Jeffrey A. Lvbarger, M.B., Dept. of Health and Human
Services
To: Michael A. McGeehin, EPA
200015
August IS, 1986
Pages: 1
Letter
Personal correspondence regarding proposals to contain the hazard
at the Gregory incline and tailings
From: Billy Jean Smith
To: James ~. Russo
200016
October 17, 1986
Pages: 4
Memorandum
Summary of demographics and community concerns
By: Ann Marshall
To: Roger 01 sen
-------
cencitv
0011410
200017
November 21. 1986
Pages: 1
Letter
Phase I and II reports
By: Sharon Kercher, Emergency Response Branch
To: Maureen Dudley, Colorado Dept. of Health
200018
December 12, 1986
Pages: 2
Letter
Memorandum o-f agreement -for the historical value o-f the crib wall
From: Sharon L. Kercher
To: Gregory Kendricks, Nat'1 Park Service
200019
December 18, 1986
Pages: 4
Letter
Request -for comments o-f the Colo, State Historical Preservation
Officer and the advisory council in compliance with 36 CFR PART
BOO
From: Sharon Kercher, EPA
To: Robert Fink, Advisory Council on Historic
F'reservat i on
200020
December 18, 1986
Pages: 4
Letter
Request for comments of the Colo. State Historical Preservation
Officer and the advisory council in compliance with 36 CFR Part
800
From: Sharon Kercher
To: Leslie Wildesen, Colo. Historical Society
200021
December 29, 1986
Pages: 1
Letter
Response to documentation request from the Historic American
Engineering Record
From: Gregory D. Kendrick, Nat'1 Park Service
To: Sharon Kercher, EPA
-------
cenci ty
0011411
200022
December 31, 1986
Pages: 2
Letter
Significance of the crib wall and the need for additional
information required by the council to complete their review
From: Robert Fink
To: Sharon Kercher, EPA
200023
January 12, 1987
Pages: 1
Letter
Historical value and the adverse effects of the constuction
From: Leslie Wildesen, Deputy State Historical Preservation
Qff i cer
To: Sharon Kercher
200024
Januarv 21, 1987
Pages: 9
Memorandum with attached documentation
Historic American Engineering Record, documentation prepared for
Gregory tailings
From: Dave H. Erickson, TAT Region 8
To: Sharon Kercher, EPA
200025
February 4, 1987
Pages: 1
Memorandum
Gregory tailings and incline operable unit of the Clear Creek/
Central City NF'L site
From: John R. Giedt
To: Robert L. Duprey
200026
February 4, 1987
Pages: 1
Letter
Enclosure of a memorandum of agreement
From: Sharon L. Kercher
To: Leslie E. Wildesen, Colo. Historical Society
-------
cencitv
0011412
200027
February 12, 1967
Pages: 1
Letter
The retainment of a portion of the
Historical value
From: Sharon Kercher, EPA
To: Director, Gilpin Historical
crib wall for the Museum -For
Society and Museum
20002S
February 12, 1987
Pages: 1
Letter
Request -From the EPA -for the immediate concurrence o-f the
advisory council on the memorandum agreement
From: Sharon L. Kercher
To: Robert Fink, Advisory Council on Historic
Preservati on
200029
February 17, 19B7
Pages: 1
Letter
Transmittal of documentation package per the Historic American
Engineering Records requirements
From: Sharon L. Kercher
To: Gregory P. Kendrick, Nat'1 Park Service
200030
February 18, 1987
Pages: 1
Letter
Informative letter describing the timber crib wall possible
collapse with the unexplanation of the results if this should
happen
From: Sharon Kercher, EPA
To: Honorable William Lorenz, Mayor City of Black Hawk
200031
February 18, 1987
Pages: 1
Letter
Informative letter regarding the
wall with oossible ramifications
water
From: Sharon Kercher, EPA
To: Ned Noack, Colo. Dept. of
possible collapse of the crvpt
of contamination of drinking
Health
-------
c en c i t v
001141
200032
February 19, 1987
Pages: 1
Letter
Confirmation of telephone conversation of receipt of construction
drawings for Gregory tailings
From: Sharon L. Kercher, EF'A
To: Kaaren Patterson, Colorado Historical Society
200033
February 26, 1987
Pages: 2
Letter
The Gabian wall placement at the Gregory tailings and questions
raised by the Colo. Historical Society
From: Buddy Hines, Robinson Engineering Inc.
To: Peter Barrett, Ecology and Environment, Inc.
200034
February 27, 1987
Pages: 1
Letter
Comments and understandings from the Colo. Historical Society
regarding the qabian wall construction
From: Leslie E. Wildesen, Colo. Historical Society
To: Sharon L. Kercher, EPA
200035
March 2, 1987
Pages: 3
Agreement
Memorandum of agreement by and among the US EPA, the Colorado
State Historic Preservations Officer and the Advisory Council on
Historic Preservation
From: unknown
To: unknown
200036
March 3, 1987
Pages: 8
Memorandum
Request for removal action funding to eliminate the threat posed
by the potential collapse of the mine tailings at North Clear
Creek
From: Sharon L. Kercher, EPA
To: Robert L. Duprev
-------
cenc it v
001141
200037
March 6, 1987
Pages: 1
Letter
In-formation to residents regarding the study and clean-up o-f the
Clear Creek/Central City Super-fund site
200038
March 10, 1987
Pages: 1
Letter
Memorandum o-f agreement regarding emergency resDonse action
From: Robert Fink
To: Sharon Kercher
200039
March 12, 1987
Pages: 7
Report
Drainage calculations -for North Clear Creek, Black Hawke, CO
From: Robinson Engineering, Inc., by H. J. Heinz
To: unknown
200040
March 16, 1987
Pages: 1
Letter
Concern about the placement o-f the Sabian wall and the impact on
personal property
From: Sharon L. Kercher, EPA
To: Mr. and Mrs. Marco Lah
200041
March 17, 1987
Pages: 1
Letter
The acceptance by the cultural resources division o-f the Historic
American Engineering Record documentation o-f the Gregory tailings
From: Gregory Kendrick, Nat'l Park Service
To: Sharon Kercher, EPA
-------
cenci tv
0011415
200042
March 20, 19B7
Pages: 3
Letter
Information regarding the need -for immediate action required to
protect the North Clear Creek
From: Sharon L. Kercher, EPA
To: Curt Musgrave, U.S. Army Core of Engineers
200043
March 23, 1987
Pages: 1
Letter
Written record of the concerns of John Liou of FEMA
From: Buddy Heinz, Robinson Engineering Inc.
To: Peter Barrett, Ecology and Environmentals
200044
March 24, 1987
Pages: 3
Letter
Authorization by the Department of the Army for the proposed work
of the Environmental Protection Agency
From: Eldon E. Strine, Dept. of the Army
To: Sharon Kercher
200045
March 26, 1987
Pages: 1
Consent form
Access to propery
From: Kevin John Roche
To: EPA
200046
March 26, 1987
Pages: 7
Report with attached communications
Flood plain development permit from the City of Black Hawk
By: Peter Barrett
To: Sharon Kercher
-------
cencitv
001141
200047
March 27, 1987
Pages: 2
Letter
Reiteration of initial design plans called for the placement of
the Gabian wall and the specific concerns expressed by the mayor
of the city of Black Hawk
From: Sharon Kercher, EPA
To: Bill Lorenz, Mayor of the City of Black Hawk
20004S
March 27, 1987
Pages: 8
Report
Site health and safety plan for the Gregory tailings project,
Black Hawk, Colorado
By; EPA
200049
March 27, 1987 through April 29, 1987
Pages: 60
Record
Dates and times of various activities associated with the Gregory
incline and mine tailings happenings
From: B. M. Thomas
To; unknown
200050
Apri1, 1987
Pages: 4
Report
Communications strategy for the Gregory tailings removal action
By: unknown
To: unknown
200051
April 1, 1987
Pages: 3
Memorandum
EP toxicity results for wood trimming samples from Gregory
tailings. Black Hawk, CO
From: Rick Chappell
To: Sharon Kercher, EPA
-------
c en c i t y
0011417
200052
April 3, 1987
Pages: 2
Memorandum
Toxicity potential of wood cribbing at Gregory tailings
From: Peter Barrett, Ecology ?•< Environment, Inc.
To: Sharon Kercher, EPA
200053
April 11, 1987
Pages: 1
Letter
Mine owner's opinion on the EPA handling o-f the Gregory incline
project
From: Chas E. Fetterhoff
To: Sharon Kercher, EPA
200054
April 13, 1987
Pages: 2
Letter
Placement of riprap material along the bank of the creek behind
individual property owner
From: Sharon L. Kercher, EPA
To: Mr. and Mrs. Marko Lah, property owners
200055
April 17, 1967
Pages: 1
Letter
Materials submitted to the National Archives pursuant to the
memorandum o-f agreement
From: Sharon Kercher, EPA
To: Director of the Gilpin Historical Society and Museum
200056
April 23, 1987
Pages: 2
Letter
Change in the final construction plans
From: Sharon Kercher, EPA
To: Leslie Wildesen, Colorado Historical Society
-------
cencitv
001141
200057
April 23, 1987
Pages: 1
Memorandum
Removal action at Gregory tailings and decision to remove the
crib wall
From: Sharon Kercher, EPA
To: The record
200058
April 23, 1987
Pages: 2
Memorandum
Gregory Tailings: decision not to install riprap on "Conoco
Bank "
From: Sharon Kercher, EPA
To: The record
200059
April 23, 1987
Pages: 1
Memorandum
Removal action at Gregory tailings and the decision to deviate
-From alignment at Gabian wall as specified in the design drawings
From: Sharon Kercher, EPA
To: The Record
200060
April 23, 1987
Pages: 1
Memorandum
Removal action at Gregory tailings and decision to use key gravel
as back-fill behind Gabian wall
From: Sharon Kercher, EPA
To: The Record
200061
May 11, 1987
Pages: 1
Letter
Justification for the change in the final construction plans and
reauest for a photo of the appearance of the finished product
From: Barbara Sudler, State Historic Preservation Officer
To: Sharon L. Kercher, EPA
-------
cenci tv
001141
200062
Mav 14, 1987
Pages: 13
Letter with enclosures
Lists of applicable and relevant state requirements, standards,
criteria and limitations -for the proposed remedial action at the
Clear Creek/Central City Super-fund site
From: Ken Mesch, CDH
To: EPA
200063
Mav IS, 1987
Pages: 1
Letter
Landowner responsibility -for clean-up costs at the site
From: James J. Scherer, EPA
To: Glen P. Anderson
200064
No date
Pages: 5
Report
Documentation package -for Gregory tailings with a description o-f
the undertaking
By: EPA
200065
no date
Pages: 1
Vicinity map
The project site
By: unknown
To: unknown
200066
no date
Pages: 3
Report
General information on the site with history included
By: unknown
To: unknown
-------
cenci ty
0011420
200067
no date
Pages: 4
Report
Historical information
By: unknown
To: unknown
200063
no date
Pages: 2
Inventory
HABS/HAER Inventory of the Gregory tailings with the significance
noted
200069
no date
Pages: 6
Record
Historic American Engineering
Historical narrative
By: Ecology and Environment,
To: EPA
200070
no date
Pages:
Di aqram
Creek isolation alternative concrete box culvert
By: unknown
To: unknown
200071
no date
Paaes:
Table
The summary of the chemical test results from North Clear Creek
above and below the Gregory tailings and from the Gregory waste
rock tailings and the ground water
By: unknown
To: unknown
Record of the Gregory tailings,
Inc.
-------
cenci ty
0011421
200072
no date
Pages: 2
Plan
The isolation alternative Gaoian wall
From: Robinson Engineering, Inc.
To: EPA
200073
July 18, 1986
Pages: 16
Report
Wrap-up report on the -feasibility o-f reorocessing the Gregory
tai1i nas
By: W. Rex Bull and Thomas R. Wildeman, The Colorado School
ot Mines
To: Camp, Dresser and McKee
200074
July 21, 1986
Pages: 9
Report
Preliminary report on the value ot the Gregory tailings
By: W. Re;< Bull and Thomas R. Wildeman, Colorado School ot
Mi nes
To: Camp, Dresser and McKee
200075
February 13, 1987
Pages: 3
Memorandum
Removal request for the Gregory incline and tailings
By: Peter Barrett, Ecology and Environment, Inc.
To: Floyd Nichols, EPA
200076
February 18, 1987
Pages: 4
Letter
Gregory tailings Central City/Clear Creek CERCLA site
From: Robert L. Duprey, ERA
To: Norman R. Blake
-------
cenci tv
0011422
200077
February 26, 1987
Pages: 1
Recei pt
Gregory tailings
Signed: Norman R. Blake
200078
March 4, 1987
Pages: 1
Record of communication
Removal action at Gregory tailings, Black Hawk, CD
From: Clair Tanner, Weekly Register
To: Sharon L. Kercher
200079
March 11, 1987
Pages; 1
Record o-f communication
Removal action Gregory tailings, Black Hawk, CO. Gabian baskets
vs riprap
From: Buddy Hines, Robinson Engineering
To: Sharon Kercher
200080
March 19, 1987
Pages: 1
Record o-f communication
Removal action: Gregory tailings. Black Hawke, CO
From: Jim Baker , Regional toxicol ogist
To: Sharon Kercher
200081
March 20, 1987
Pages: 4
Letter
Gregory tailings, Central City/Clear Creek CERCLA site
From: Robert L. Duprey, EPA
To: Gerald J. Devitt o-f Devitt and Weiszman, Attys at law
200082
March 23, 1987
Pages: 1
Record o-f communication
Removal action: Gregory tailings, Black Hawk, CO
From: Mel Cassidy
To: Sharon Kercher, EPA
-------
csnci tv
0011423
200083
March 24, 1987
Pages; 1
Memorandum
Data quality review training, April 14, 1987
From: Diane Short, Richard Cheatham, REM II
To: Region 8 EPA
200084
March 24, 1987
Pages: 1
Record of communication
Removal action: Gregory tailinos. Black Hawke, CD/Health Safetv
From: Cindy Coe, 0SHA Health Regs. Team
To: Sharon Kercher, EPA
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0011424
ADMINISTRATIVE RECORD
SF FILE NUMBER
S.i
APPENDIX D
STATE OF COLORADO CONCURRENCE WITH REMEDY
-------
COLORADO DEPARTMENT OF HEALTH
STATE OF COLORADO
. oU ^
4210 East 11th Avenue
Denver, Colorado 80220
Phone (303) 320-8333
Roy Romer
Governor
U.S. Environmental Protection Agency-
Region VIII
One Denver Place
999 18th Street, Suite 500
Denver, Colorado 80202-2405
December 22, 1987
Thomas M. Vernon, M.D.
Executive Director
Attn: Robert Duprey
Dear Bob:
This letter will serve to provide Colorado's concurrence with the
proposed remedy for discharge treatment (Operable Unit #1) at the Clear
Creek/Central City superfund site, in Clear Creek and Gilpin Counties,
Colorado. The remedy selection process is described thoroughly in an
attachment to the record-of-decision dated September 30, 1987.
The proposed remedy authorizes pilot investigations of passive wetlands
treatment, followed by further refinements using active conventional
treatment if pilot testing indicates the need. Discharges from five
sources (the Big 5, Argo, Quartz Hill, National and Gregory Tunnels) are
now slated for remediation, but control strategies for other surface
discharges and ground water contributions will be investigated before a
final treatment remedy is selected. Also, while we recognize that source
control is not likely to eliminate all discharges in the region, the
proposed remedy acknowledges the need to investigate source control's
effectiveness for improving water quality and minimizing the volume of
flow to be treated in the long term.
The concurrence provided by this letter applies to the technical aspects
of the proposed remedy. SARA states that permits are needed for remedial
activities that are not entirely on site. The discharge from this
operable unit would not be entirely on site and a permit should be
required. Policy concerning permitting requirements is currently being
discussed by the state and EPA.
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Mr. Robert Duprey
December 22, 1987
Page Two
If you have any questions, please call Jeff Deckler at 331-4830
Sincerely,
Thomas P. Looby
Assistant Direcftor
Colorado Department of Health
cc: Bill Geise, Jrr
Ken Mesch
Dan Scheppers
Jeff Deckler
Walter Sandza
TPL:nr
-------
COLORADO DEPARTMENT OF HEALTH
Drinking Water/Ground Water Section
0011427
INTER-OFFICE COMUNICATION
TO: |Dave Shelton
FROM : Paul Ferrari
DATE: December 18, 1987
SUBJECT: Concurrence: Record of Decision, Clear Creek/Central City Operable
The ARARS and standards in the ROD appear to meet State aquatic, river,
health and groundwater standards and requirements, the proposed remediation
and contingencies appear to be viable. Therefore, this Division concurs with
the subject Record of Decision excepting as follows:
1. Appendix B, page 1 and table B-2 — OHEP policy is that CPDES permits
must be issued at CERCLA/Superfund sites for discharges to State waters
from treatment plant/passive-treatment systems. Accordingly, the
Division does not agree with the ROD statement that no permits are
required.
2. Page 2 (executive summary) and page 12 (main body) — the Division does
not agree with the ROD that geometric means should be used instead of
arithmetric means to determine ambient and effluent means for metals,
etc., for purposes of compliance with ARARS or standards. In addition
to being non-comparable between data sets and in error (low) compared
to arithmetric means, the use of geometric means, applied to water
contaminants, creates a false tolerance for exceedence of stream
Unit No. One
standards.
PF/ls
xc: John Leifer
Tom Looby
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