,
United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPAIRODIR08-93/068
U"'."'n 1993
PB94-964416
&EPA
Superfund
Record of Decision:
Eagle Mine, CO
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..Kaz.ardbur.WOste COt~,
IOtorrnatIor'\ResourC$ .. teotef
~,.EPA,.~.3 .
PhIlQdefPh(t~PA 19101
EP A Report Collection
1 Information Resource Center:
us EP A Region 3
Philadelphia, PA 19107
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EAGLE MINE SITE
OPERABLE UNIT 1
DEClARATION FOR TIlE RECORD OF pECISION
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EAGLE l\DNE SITE - OPERABLE UNIT 1
Declaration for the Record of Decision
Site Name and Location
Eagle Mine Site, Operable Unit 1
Eagle County, Colorado
Statement of Basis and PutpOse
This dPd~inn document presents the selected remedial action for the Eagle Mine Site, Operable
Unit 1 (OU-l) ("Site"), located in Eagle County, Colorado, which was chosen in accordance
with the requirements of the Comprehensive Environmental Response, Compensation, and
Liability AJ;t of 1980 (CERCLA), as amenrlM by the Superfund Amen~ and
Reauthorization Ai;t of 1986 (SABA) aDd, the N~I CODtingency Plan ~cp). This decision
4uc~ent explains the basis and pulp.OSe of the selected remedy for the Site.
The lemem:lll .adicn desc1'1ned in this document is "in addition to" the State of Colorado (State)
clean up action which began in 1988 under a Natnn) Resource Damages (NRD) suit filed under
CERCLA. The information supporting the State's decision under the NRD suit.is contained in
a separate Administrative Record.
Assessment of the Site
Actual or threatened releases of hazardous substances from the Site, if not addressed by
implementing the response action selected in this Record of Decision (ROD), may present an
imminent and substantial danger to public health, welfare, or the environment.
Description of the Remedy
This Operable Unit, one of two designated for the Site, addresses the principal sources of mine
waste pollution that are impacting lhe Eagle River and . certain ground water resources. The
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pmpose of this Operable Unit (aU-I) is to control the transport of tone metals ori~mlti"g from
various sources to the Eagle River and to Site ground waters. The identified sources include the
:Eagle Mine, the Roaster Pile area, the Waste Rock Piles, Rex FIats, the Old Tailings Pile
(OTP), the Consolidated Tailings Pile (CTP) and the Maloit Park Wetlands.
.The environmental receptors of concem are the tIesh-water biota, particu1arly the :Eagle River
aquatic life. Human health concerns inC:~JJde potP.nti~ 1 impacts and possible re-entrained soils .
conClmination from $e CTP to children and employees attending the Minturn Middle School and
to full-time residents who live adjacent to the school from wind-blown particulate matt~r from
the Consolidated Tailings Pile (CTP). There are also human health concerns related to potential
future coDClmination of the Town of Minturn drinking wate~ wells.
The major components of the selected remedy inc1nde:
.
JD.mtThmon of a &ystcwto ~ :aMitinma1 mine seepage along Rock Creek:
.
Diversion of Rock Creek ~ of c:onrnmimtted mine seepage
.
ExpeditjDg rcv~rinn in the area ofl~oaster Pile I and ~ dmnage, and
d1\>uitu1iug of seep water quality below the Roaster Pile 1 area .
.
Surface water mn-off and ~ound water monitoring at the Waste Rock Piles,
leachability tests on the waste rock, with evaluation of the data for possible future
action
.
Development of an inspection and maintenance plan to ensure the long-tenn'
integrity of stIUctures and facilities associated with the :Eagle Mine Site
.
Implementation of use restrictions for ground water at the Rex Flats and OTP and
accelerated revegetation at Rex Flats
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.
Rapidly complete the cap on the crP, drain and cap the historic pon~ extraCt
and treat leachate/ground water from the crP extraCtion trenches, enhance
crP extraction trenches, constrUct a new up-gradient ground water diversion
StrUctUre and relocate the Town of Minturn drinking water wells
.
Continue the treatment ,of con~Triinated mine seepage and leachate/ground
water from the crP at the Water Tr~anncrot Plant (WI'P) until Site cleanup
goals can be met ,without such treatme~ dewater the treatment sludgey and
dispose of the dewatered sludge in on-site lined cells on the CI'P
.
Remove the cont~minated soils and sediments from the Maloit Park
Wetlands, control seepage from the CI'P, and rapidly add topsoil and
revegetate
.
Contb.Jct regular monitoring of surface water, groundwater, mine poo4 and
biota at e, lOw&ti()~ on the Site and downstream of the Site to determine
progress toftfd cWinnp goals
The components noted above represent the current selected remedY. EP A recognizes that
there is ODgoing research into alternate remedies and encourages the responsible party to
continue this research.
A separate Operable Unit, OU-2, has been established to evaluate additional potential
hwnan health risks at the Eagle Mine Site. 'These concerns relate to: the potential wind-
blown metals deposition in the south end of Minturn and in the Minturn Middle School
area; the potential future risk from metals in soils and waste rock in the Town of Gilman
and; the potential' con~mination of private drinking water wells in the Minturn area.
Statutory Determinations
The selected remedy is protective of human health and the environment, complies with
Federal and State requirements that are legally applicable or relevant and appropriate to
the remedial action, and is cost-effective. This remedy utilizes permanent solutions and
alternative treatment technologies to the maximum extent practicable. A substantial portion
of the metals loading will be removed by collection and treatment of contaminated surface
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and ground water. The remainder of the metals loading will be controlled through capping
and revegetation.
. Because this remedy will result in hazardous substances rem~;n;ng on-site above health-
based levels, a review of the remediation will be cOnducted five years after commencement
of remedial action to ensure that the remedy continues to provide adequate protection of
human health and the environment.
'(~ ..
. ~41./ ftP!yf /'
ad: W4 M~( ictin~ Administrator
Region ~ Environmental Protection Agency
MAR 2 9 1993
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EAGLE MINE SITE
OPERABLE UNIT 1
DECISION SUMMARY FOR THE RECORD OF DECISION
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TABLE OP COH"l'D1TS
Section
Title
I.
OVERVIEW
A. Selected Remedy
B. Changes from the' Remedy Presented in FSA and
Proposed Plan
New Alternatives Suggested by the Public and Not
Pre~ously Considered
~evel of Community
Alternatives
C.
D.
Support
for
Selected
II.
BACKGROUND ON COMMUNITY INVO~VEMENT
A. Communi ty InvclveIJ1~nt During FSA
B. Identification of Key Public Issues
C. Modifications in Response to PubJ.ic
COtJ"IfftPT1tS
III. ~y OF 'COMMENTS RECEIVED AND AGENCY RESPONSES
A. Summary and Response to Local community Concerns
B. Compreh~nsive Response to Specific Technical and
Legal Couments
rv .
Response to Legal Comments
i
pacre
1
2
4
7
8
9
9
9
11
12
12
47
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SECTION TITLE PAGE
VL sUMMARY OF SITE RISKS 19
A. Sources of CoDt~min~nts of Concem 19
B. Human Health Risks . 20
C. Enviro~ental Risks 23
vu. DESCRIPTION OF ALTERNATIVES 24
A. Development of Remedial Action Objectives and Goals 24
B. Description of Alternatives 31
vm. COMPARATIVE ANALYSIS OF ALTERNATIVES 48
A. Eagle Mine Seepage 48
B. Waste Rock PilesfBe~n Non-Point Sources 50
C. ~ Piles 52
Do. Rex RatS/Old T.ai1i~gs Pile Areas 53
E. Coosolidated T~m~ Pile" 54
F. Maloit Park Wetlands 56
G. Water Treatment Plant 57
IX. SELECIJ::JJ REMEDY 59
X. STATUTORY DETERMINATIONS 68
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SECTION
L
II.
III.
IV.
v.
EAGLE MINE SITE
DECISION SUMMARY FOR 'mE RECORD OF DECISION
TABLE OF CONTENTS
T1"I'LE
SITE NAME, LOCATION, AND DESCRIPTION
SITE HISTORY AND ENFORCEMENT AcnvmES
A. Description and History of the Site
B. .Status of State Oeanup
C. EPA's Feasibility Study Addendum
D. EP A's Proposed Plan; Projected FutUre Remedial Efforts
E. Pot~ny Responsible Party (PRP) Response Actions
F. Potenti~l1y Respoasjb1e Parties
L . Par-c:UIlUWIt Ccku,lhJftication Inc..
2 Glem T. Miller doing business as Miller Enterprises
3. Ba~ Mo-..u~in Corporation
. G. Past T'ic11~nce of Notice Letters .
HIGln.IGHTS OF COMMUNITY PARTICIPATION
SCOPE AND ROLE OF OPERABLE UNIT WITHIN SITE
STRATEGY
SUMMARY OF SITE CHARAcrERISTICS
A. Eagle River
B. Eagle Mine Seepage
C. Waste Rock Piles/Belden Non-Point Sources
. D. Roaster Piles
E. Rex Flats/Old Tailings Pile Areas
F. Consolidated Tailings Pile
G. Maloit Park Wetlands
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5
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EAGLE MINE, OPERABLEUN1T 1
Decision S.,mmsary for the Record of Decision
L
SITE NAME, LOCATION, AND DESClUPfION
The Eagle Mine Site is a large abandoned mining and mining facility located along the
banks of the Eagle River near Minturn, Colorado (see Figure 1). The boundaries of the
Site are defined by the areas of past mining activity between the towns of Red Cliff and
Minturn. There are assoc:ia.ted impacts from Site contaminants which extend downstream
in the Eagle River, possibly as far as Gypsum, Colorado. The 235-ac:re Eagle Mine Site,
referred to in this document as the "Site", includes the Eagle Mine Worlcings, the town of
Ginmm, the mine tmHngs pond areas, Rex Flats, Rock Creek Canyo~ and waste rock and
roaster pile areas (see Figur~ 2). The Site is bordered on the south and west by the White
River National Forest which includes the Holy Cross Wilde~ Area. Access to the
wilderness ar~ runs Lluoagh the Site and next to the historic location of the Old T:ti1in~!'
Pile (OTP).
The Eagle River is the major surface water resource affected by the metals contamination
from the Site. The headwaters of the Eagle River origjn~te about 15 miles above Red Cliff.
The Eagle River flows north-northwest through the Site to the town of Avon where it turnS
generally westward until it joins th~ Colorado River at Dotsero. The Eagle Mine workings
. were developed in the lower levels of Battle Mountain to the east of the Eagle River and
just south of Rock Creek. Several wetland and former wetland areas border the Eagle
River betWeen Red Ciff and Minturn. Rex Flats, a low lying area which was once a
wetland, is located on the east side of the Eagle River across from the OTP area about
three miles north of the mine. The OTP area was a hay meadow prior to the advent of
mining operations. Another tailings disposal unit, the New Tailings Pile is called the
Consolidated Tailing Pile (CI'P) in this ROD. The crP is located about a mile north of
the OTP just west of the Eagle River and south of Cross Creek. The Maloit Park Wetland
along Cross Creek. has been affected by surface water and ground water flowing from this
pile.
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The Eagle River is used as a ~ supply. and for recreation (Le., rafting and kayaking).
FIShing also oc:curs on the Eagle River from the headwaters to the Colorado River. There
are numerous diversions from the Eagle River for municipal supply, stock watering, and
irrigation downstream from the confluence with Gore Creek. The closest residence to the
Site is 1,000 feet to the northeast along Highway 24. Minturn, the closest population center,
with 1,500 people, has filter ponds and municipal wells located northwest of the crP and
aaoss Cross Creek. Minturn draws its public water supply both from area wells and from
Cross Creek.
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....."'. - .
. Minturn ~ WeBs
o
I
!Celie in mi les
.2
I
north
~
MaIoit Park Wetiands
New Tailings Pile
)
.r1-
. Corridor
\
.It' Rex Rats
,
Coloraoo
Roaster Piles
1.2.3. and 4'
(HistonCaI)
FtgUfe 1
Site Location Mac.
Eagle Mine Super Fund Site
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o
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scat- in mites
in
1
Figure 2
Site Ma~
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D.
. SITE IUSTORY AND ENFORCEMENT AC1'IV1TIES
A.
DescrintioD and Histor:v of the Site
The Eagle Mine Superfund Site is located near Minturn in Eagle County, Colorado.
J'be Eagle Mine area are deposits, a large body. of zinc and lead ores, along with
some precious metals, were first mined in the 1870's. Early in the 1900's, the New
Jersey Zinc Company consolidated a number of these workings and operated them
as the Eagle Mine until 1966 at which time the company was merged with Gulf +
Western. Ine. .
The Eagle Mine workings are underground. At the turn of this century, ores were
proc:essed by "roasting. It Residues from this process were left in five "roaster piles, n
three on the west side of the Ea.gieRiver and two on the east side. I...ater~ a mill was
\.vlDtulcted underground to process ores. Mill t~mn~ were slurried down valley and
. deposif'pd at the CJI1». T~1in~ were also deposited in the Rex Flars area and some
were left under the shmy tine, probably through accidettta.t spillage. When the OTP
area was "fulI" the sluny line was extended further .to the north and the New Tailings
Pile, now called the CoDsoIidated Tailings Pile (crP), was created. Tailings and
poJluted water ran off the New Tailings Pile depositing me1~k in cuijacent Maloit
Park Wett~nds.. Ground wat~r in the Rex Flats, Old and New Tailings Pile, and
Maloit Park Wetlands area became poJluted. Impacts to the Eagle River from Site
cont2mjnan~ have been noted downstream, possibly as far as ~ Colorado.
Gulf + Western. which has since changed its name to Paramount Communications,
Ine., operated the Eagle Mine unti11979. In 1983~ Gulf + Western sold the property
to Mr. Glenn Miller. Mr. Miller immediately sold portions of the surface property
to the Battle Mountain Corporation and also attempted to operate the mine for a
short period of time. The mining operation was abandoned in 1984. Battle
Mountain Corporation obtained a loan from a Texas savings and loan and later
defaulted. The savings and loan has since become insolvent and has been taken over
by the Federal Deposit Insurance Corporation (FDIC). The FDIC has not yet
foreclosed on the property and holds the notes to the Battle Mountain property.
In 1983, the State of Colorado filed a complaint against Gulf + Western and the
New Jersey Zinc Company for natural resource damages under the Superfund
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statute. In 1986, the State amended their complaint to seek injunctive relief against
Gulf + Western. In 1986, the EPA placed the Eagle Mine Site on the National
Priority Ust, making it a designated Superfund Site. EP A and the State entered into
a MemorandUm of Agreement (MOA) in 1986 which designated the State as 1ead"
agency for the Site cleanup.
The State and Paramount resolved their lawsuit in 1988 when the tWo parties entered
. into a Consent Dec:ree/Remedial Action Plan (RAP). This agreement included the
following major provisions 1) phWng the mine adits and grouting frac:tu.re zones to
flood the mine workings to stop the generation of acid mine drainage; 2) removal of
roaster piles; removal of tailings from Rex Flats, the pipeline corridor, the toes of
CI'P, and the Old Tailings Pile, and removal of contaminated Maloit Park wetland
soils with consolidation of those materials at the CTP; 3) capping and temporary
ground water pumping at the CTP, and; 4) setting compliance objectives and long-
term monitoring of surface water, ground water, mine water, vegetation., soils. CfP
settlement and erosioD. Compl~n~ st~nti~rds were set for dissolved zinc
<:oQC("'ftt'rMinn< in the Eagie River, for soils cleanup (lead and pH c;t:Incfm-ds), and for
cc:vc;g~tation criteria.
The RAP also required nm-on div~rsinn. ditches at the waste rock piles; site-wide
tr.e~nnPnt of t]TInerJy;j1g soDs for pH adjustment, removal or isolation of soil with
high lead levels cmd revegetation of disturbed areas. Temporaxy surface mnoff and
run-on Q.lutt.ol at Rex FIats, OTP, and CI'P were required as were an upgradient
ground water diversion ditch and tWO ground water extraction trenches at the CTP,
removal of Wstmic pond on top of CTP and constrUdicn of lined surge pond at CTP.
Other RAP provisions included diversion of lower Rock Creek, disposal of
contaminated water at the site, regrading and stabiH'7ing the CTP, dust control during
construction, installing an Eagle River gauging station and connecting the Pierson
house to the municipal water supply. 'IbeRAP included a Construction QA/QC
plan, construction element approvals by State inspectors, final constrUction reports
and a State inspection and certification program.
EP A reviewed the Consent Decree/Remedial Action Plan and found it generally
"environmentally acceptable," but expressed reservations about its ultimate success.
EP A believed this success would have to be demonstrated by continued monitoring
of Site conditions.
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B.. Status of State aMlIIUV
Although significant progress has been made at the Site, concerns about the
effectiveness of the cleanup and evidence Ot difficulties in its accomplishment
appeared in late 1989 and early 1990 when metals concentrations in the Eagle River
were extremely high. . In May 1990 the State and Paramount amended the Remedial
Adion Plan and -added: a chemical water treatment plant, a second lined surge
pond, a mine seepage collection system, expanded ground/surface water monitoring,
~nm1~J cournmin~nt 109din! report, temporary sludge disposal at CI'P, Rock Creek
grouting and evaluation. and OTP ground water reduction. Operation of this
treatment plant which presently treats mine seep water and ground water and surface
water from the CTP bas improved the water quality of the Eagle River. The State
continues to pursue additional cleanup measures under its Consent Decree including
improvement of mine seep collection. removal of additional- roaster material, and
revegetation of disturbed areas. .
One notable aspect of the RAP relates to how Paramount was to achieve compliance
with the water quality goals set in the Eagle River. The Eagle River water quality
goals were set at 150 J1g/l dissolved Zn below the. mine and 250J1g/1 dissolved Zn
immeq;~~ety above the confluence with Cross Creek. The goaLs were to be met in
5qlb;wber of an average flow year and were to be averaged over 30 days. In
conuast, EPA be1ieves that thecrmcaJ time of year for meeting in-stream standards
that will lead to re-estabJi!i:hing the aquatic comm11nity including a viable fishery may
be during the low-flow period in late winter.
Another aspect of the RAP that EP A has noted is the absence of consideration of
possible ground water problems in the CI'P jMaloit Park Wetlands area. Minturn
operates municipal wells that draw water from an aquifer that could potentially be
impacted by leachate from the CI'P. This problem has been alleviated by a recent
agreement whereby Paramount will provide Minturn with new drinking water wells
which are. cunently under development. In addition, because of the upstream
location of the surface. water compliance points adopted in the RAP, the full impact
of the contaminated crP Maloit Park ground water on Eagle River water quality is
not reflected in the data.
On April 4, 1991, the Water Management Division at EPA issued a Notice of
Violation (NOY) to the CDH for alleged violations of Section 301 'of the Oean
Water Act by Paramount. These alleged violations included discharg~s from various
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mine seeps and discharge from the Roaster Pile area. The Water Division action
was coordinated with the Superfund program with EP A viewing the NOVas an
opportunity to compel additional clean-up actions at the Site.
. The Colorado Department of Health responded to the NOY on November 1, 1991.
In lieu of further NOY action, CDH and Paramount agreed that Paramount would
do additional. work in the Roaster Pile area. collect additional mine seepage, and
explore the possibility of collection of subsurface mine seepage in the colluvial
material in Rock Creek. CDH also was to pursue Paramount for payment of fines
for several of the alleged violations. EP A accepted this proposal.
c.
EPA's Feasiltili(V Study Addendum
In the fail of 1990, EP A announeed it would conduct a .FeasibiIity Study Addendum
(FSA). The purpose of the FSA was to help solve Site problems using Federal
.3U1ftnririt'!!IL It was called an "Addendum" be~n~ it was being done ""m addition" to.
aDd cnn~;srll!M with, the large effort already underway by the State of Colorado. The
FSA was released to the public aD JuDe 17, 1992. and serves as the technical and
mmlytical basis for the Proposed Plan, and this ROD..
D.
EPA's P'rQ1J8M!d Plair. Pwon~ Future 1l,.mPdi~1 Efforts
The Proposed Pian for OU1 was released to the public on June 3~ 1992. The public.
comment period was first extended to August 30, 1992 and again to September 14,
1992. The extension was specifically to allow complete comments on the water
quality standards.
EP A has recently concluded that additional risk assessment must be conducted at the
Site due to possible wind-blown deposition of metals into populated areas of Minturn
and the nearby Minturn Middle SchooL A screening of soils was initiated in
September 1992. In order to expedite the ROD process, this additional soils work
has been separated from the remainder of the Site and classified as Operable Unit 2.
If no significant risk is found, EPA will document a "no action decision" on OU~2.
If significant risk is found to exist, OU-2 will be the subject of a complete RIfFS.
Proposed Plan, and a Record of Decision.
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'E.
PoteDdaU:L..R~Dsible put\' ~Dse Actions
In 1981 Gulf + Westem personnel entered the mine and drained fluid containing
polychlorinated biphenyls (PCBs) out of three tranSformers located in an abandoned
portion of the mine. These three tranSformers were drained and flushed but an
esrim~ted 28 lbs of PCB rem~ined. EP A has determined that there is very low risk
associaterl with the limited amount of PCBs reU'~ining in the mine. In 1984 the
Colorado Public Service Company notified EP A that it planned to shut off electric
power to the mine due to unpaid bills. If power was shut off the mine would flood
and a quantity of other electrical equipment con~ining PCBs would be under water.
Accordingly, EP A conducted an Emergency Response Action in June 1984 and
removed all but the three previously noted tranSformers from the mine.
In 199~ EP A became aware that hazardous substances may have been abandoned
at the Eagle Mine Site, iD~1J(Hng the company town of Gilman. A confused
OWD.e"hip sitl1~1ion and apparent lack of day-to-day control of access to the property
heightenedEPA ~
~~. EPA decided to c:onduc:t a Site ~dion and ass~nt of the entire
property. Tlris de.dsion -was discussed with personnel from the Colorado Department
o! Health, who decided to participate in the inspection and possible removal
EP A and CDH represcJ1tatives amdncted the inspection over several days beginning
on October 8, 1991. A quantity of hazardous substances were found including
e&9luMVes, labulCl.tUI)' chemic:aJs, PCBs, and one radioac:tive \1ial.
Ceanup negotiations were concluded on November 21, 1991, when Paramount and
the State signed an amendment to the RAP that allowed Paramount to conduct a
removal action. Paramount began the. removal action immediately after the signing
of the agreement. Although various problems arose that kept Paramount from
meeting the target date of June 1992, the removal was essentially, completed by
September 1, 1992.
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F.
L
Paramount CommunicatioD IDC.
A subsidiary of the New Jersey Zinc Company (NJZ), the Empire Zinc Company,
operated the Site from 1915 until 1938. NJZ operated the mine from 1938 until it ..
merged with Gulf + Western Industries, Inc on Febnwy 2S, 1966. NJZ conducted
hard rock mining adivities at the Site that resulted in the creation of acid mine
drainage and waste rock piles. that contrIbute to conrnminanon at the Site.
Paramount Commnnications Inc, formerly known as Gulf + Western Industries, Ine.
is the successor in interest to NJZ. Gulf + Western changed its name to Paramount
Commt)nications IDe. on June S, 1989. Gulf + Western sold the Eagle Mine Site on
September ~ .1983. Paramount is potentially liable under CERCLA as a past
operator of the facility at the time of disposal.
2.
~nT. Miller doing busiDess as Miller Eaterprises
Glenn T. MiDer, .doiDg ~ as Miller Enterprises (Miller), acquired all of the
'Site property.formerly owned and operated-by NJZ/Gulf + WestemIndustTies Ine.
on Sc.ptember 1. 1983. On the same day~ MDler soJd applll~;lIIarely 1,400 acres of
the 6,500 acresobtaiaedfrom Gulf -+ Western Industries Inc. to BattJe MOI}nt::.in
Corporation. Miller brieDy opera%ed the faati1y but almost ~~y defaulted
on the purc:base agr~~ with Gulf + Western. Furthermore. Miller did not pay
taxes on the property and consequently tax lien sales were conducted in 1984 and
1985. Appiications for treasurers deeds are currently pending Treasurers deeds
were scheduled to be issued for a portion of Millers property on August 24, 1992
and October 26, 1992 9ther parcels which were sold at tax lien sales have not been
scheduled for issuance of treasurers deeds. Glenn Miller is potentially liable under
CERa.A as a part owner and operator of the facility.
3.
Battle Mountain CorporatioD
On September 1, 1983, Battle Mountain Corporation (BMC) acquired the surface
rights to approximately 1400 acres of property within the Site boundaries. Situated
on a portion of the BMC property were tailings piles which are the subject of
remedial action at the Site.
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BMCs acquisition of the subject property.was secured by a Deed of Trost to the
. State Savings and Loan of Lubbock, Texas. As a result of a series of tranSactions,
this interest in the property was ulrim~tely assumed by the Federal Deposit Insurance
Corporation (FDIC) when it took over the insolvent State Savings and Loan.
BMC was incorporated in Colorado on August 9, 1983. BMC is currently listed as
a -suspended8. corporation by the Colorado Secretary of State. BMC is potentially
liable under CERCLA Section 107(a) (1) as a current owner of a portion of the
. facility.
G.
Past Issuance of Notice Letters
EP A has not ~ed any general or special notice letters.
IlL
HlGIU.JGHTS OF cOMMUNITY PARTICIPATION
The Feasibility Study Addendum (FSA) for aU-l of the Eagle Mine Site was released to
the ~c for comment on June 17, 1992The Proposed Pian for aU-1 was released to the
public for comment on June 30, 1992.. These tWO documents were made available tQ the
public in. the Administrative Record rrt-.\;,1f~inf!ti at the Town Manager's Offic~ Minwrn
MunU-ipal Bui]rl;ngJ MiJ1tnm, Colorado, and at the EP A Region vm Superfund Records
cemerin Denver, Colorado. Both these documents were also given wide public
distribution.
The notice of availability for the FSA, th£ Proposed Plan, and other documents in the
Atim;n;~trative Record was published in the Vail Daily and Eagle Valley Enterprise on
July 2, 1992 Other notices appeared in the Vail Trail on July 3, 1992, and ABC Times on
July 8, 1992 The initial public comment period was from June 30, 1992, to July 30, 1992.
Upon timely request, the public comment period was first extended for 30 days to
August 30, 1992. A second extension until September 14, 1992 was made specifically to
allow fumer comment on the issue of water quality goals and standards.
A public meeting was held in Min~ Colorado, on July 22, 1992, to allow the public an
oppommity to provide comments on the Proposed Plan and to ask representatives of EP A
about the Site and about the remedial alternatives under consideration. A response to
substantive comments received during the public comment period is included in the
Responsiveness Snmmary, whict1 is part of this Record of Decision.
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This decisiol1 document presents the selected remedial action for OU-1 at the Eagle Mine
Site, in Eagle County, Colorado, chosen in accordance with CERCLA as amended by the
Superfund Amendments and Reauthorization Act with the National Contingency Plan. The
decision for this Site is based on the .Admini~ttative Record.
IV.
SCOPE AND ROLE OF OPERABLE UNIT WITHIN SITE STRATEGY
The remediation measures descnbed in this Record of Decision are additions and
modifications to the substantial clean up measures agreed to, and' implemented by
Paramount Communications, under the 1988 Consent Decree/(RAP). OU-l, developed
under EP A's FeaSIbility Study Addendum analysis of Site problems and alternative solutions,
is one of two operable units within this Site. .
aU-1 encompasses the major environmental problems at the Site and public health concerns
as rp1Med to the Town of Minturn's municipal drinking water supply, to the students and
employees at the Minturn Middle School and to Maloit Park residents. A final
detennirt!2rion on risk, md dean up measures if warranted, related to the Minturn Middle
School and Maloit Park willmn be made until the completion of addWonal risk as~~')TTt.@nt
activities under OU-2, wbic:b bas been tenDed "Soils. If cU-l focuses on the transport of
metals 'to the Eagle River from Eagle. Mine .seepage, the Bna~eT Piles, the Waste Rock
Piles in the GilmanfBelden area, Rex Flats, the Old Tai~ Pile, the CI'P, and MaIoit
Park.
Based on data for the months of NoveInber through April in 1990, 1991 and 1992, EPA has
determined that about 40 to 60% of the increase in metals loadings in the Eagle River at
the Site is from Eagle Mine seepage; about 10 to 30% is from non-point sources in the
Belden area; approximately 2-3% is from the Roaster Pile area; and about 15 to 40% of the
, increase in load is from the crP area, primarily by ground water originating from the latter.
The Rex Flats and OTP areas contnbute an unquantified load during snow-melt and storm
events. The relative contnbution of metals loading for each major source area is variable
depending on seasonal impacts, storm events, snowmelt, and the inherent imprecision in
measurement of stream flow volume.
OU-2 encompasses the soils in the MintUrn Middle School area and in an approximate 2
square mile area in the south end of MintUrn; the surface soils and waste rock piles in the
Town of Gilman area, and private drinking water wells possibly being used in the Minturn
area. OU-2 was created to address human health risk concerns related to potential wind-
blown deposition of metals in populated areas from the Consolidated Tailings Pile, from
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potential wen con~mina,tion near the Site, and from potentially elevated metals
concentrations in soils and in waste roa located in the town of Gilman which may be
reinhabited in the future. OU-2 will result in either a No ACtion or a complete ROD as per
OU-1, depending on the results of the risk analysis currently underway.
v.
SUMMARy OF SITE CHARACl'ERIsrICS .
Over the last 100 years, zinc: mining resulted in the deposition of about 8 to 10 million tons
of mine wastes and mill ~i1in~ along the Eagle River. Degradation of surface water and
ground water is believed to be caused by acid mine drainage and seepage containing toxic
metals which have been transpOrted into surrounding media.
In the original Remedial Investigation (RI) done for the State of Colorado by Engineering
Science in 1985, the me
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- .
'Ibis section descn"bes the sources of cont~min~tioD, the estim~ted quantity of CODt~mina.nts
and the uncertainties associated with these estimates. A brief description of the nature and
extent of cont~mina.tion for each source area is presented in the following sections.
A.
J:aele River
As stated earlier, the quality of the water in the Eagle River has been degraded by
the historic waste disposal activities, by the dosing of Eagle Mine and by some of the
remedial activities conducted at the Site.
The Eagle River is generally a ~ining stream across the Site with the exception of
the segment associated with Rex FlatS/OTP, which is generally a losing reach.
Streamflow in the Eagle River at the Site is characterized by high flow rates during
late spring and summer runoff and a relatively stable baseflow period during the fall,
winter and early :'pli.ag. In 1990, measurements taken at the USGS station at the
Highway 24 bridge located in the middle of the Site, show a range in flow from 13
cubic feet per second (cis) on Jamw:y 4 to 881 cis on June 5. The Eagle River low-
flows calc:ulat~d in the Water Treatment Plant discharge permit are presented in
T.able V-l; these.are ~verage'seasorntllow-t1ow rates based upon statistical analysis
of flow rate measurements collected at the Site over a. number of years. The Eagle
River water quality for the November through April base~t1owperiod are presented
in Table V-2.
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Table V-I
Eagle River Low-Flows
Chromc
(3E30)%
Em!
13.0 ds . November through April
40.0 ds - May through July
28.0 'ds - August through October
16.0 ds . November through April
35.0 ds ~ May through July
1:1.0 ds . August through October
I!B
Acute (1E3)1
1 AI:1IIC tb8 acme law flow "811118 ~t tb8 cmpiricaiIy b8Ied 14ay \ow flaw witb aa avaap l-io-3-
yar ~ iDICIV81
~ die dIIaIIiI: la1t' no.... '''I'._L die .....p;.ic:8IIy b8Ied ava8F JO-day low flow with aD
na8F l-iD-3-,ar £~..&~ iIIIaftI.
MONTH
Table v-z
Eagle Ri¥el' 'Water QwWtT
November. April
DISSOLVED ZINC (MGfL)
YEAR
89 . 90 90 . 91
November NA 1.2000
December 2.9400 1.5500
January 3.6400 1.9000
February NA 2.7000
March 3.6500 2.0400
April NA 2.0000
91 . 92
1.3000
1.7700
1.7000
1.6000
1.3900
0.940
IWatcr quality data (or samples collected at station 8-138 below CI'P. Data (roM Dames &: ~oore. Site quarterty
aad aaDuU repons.
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As indicated in Table V -2, water quality in early 1990 was severely impacted by
remedial consuucnon activities which were being implemented at the various source
areas at the Site; Site sUrface water quality during this period Was the worst since
regular sampling. was initiated at the Site.. Surface water quality is generally
improving, although monthly sampling does not. indicate a completely improving
trend and the final water quality is not predictable. Water quality is now
app~hing the quality in 1985, prior to starting the cleanup. Metals concentrations
are still !rigJ'lificantly above the levels set forth in the final remediation goals.
Another issue of concern is the seasonal pattern of metals concentrations in the
Eagle River. Metals concentrations are generally most elevated during the winter
and early spring, with the highest concentrations occurring between mid-February and
early April. This is a critical period because the fry of certain species of trout
emerge during these months. The fry is the life-stage that is most sensitive to metals
concentrarions.
B.
~. Mille ~~
Water rerninerl inthc flooded mine works .percolates throu:gh fra.ctures in the .
suIroundmg rock mass and enmmltes at several locations as surface and subsurface .
seeps. Seeps occur from the mine near Belden and along Rock Creek. Most of the
surface seeps are being collected in both areas; subsurf~ seepage is indicated to
occur predominantly along Rock Creek. The current zinc concentrations in selected
Rock Creek surface seeps range from 60 to 100 milligrams per liter (mgjl).
Uncollected surface seeps near Rock Creek, surface flow in Rock Creek and
associated subsurface flows represent the principal source of metals loading to the
Eagle River, co~tributing from 40% to 60% of the total loading dunng the November
to April baseflow period. Estimates for the baseflow period of 1991 place the
loading from Rock Creek seeps between 35 to 130 pounds per day (lbsjday) of zinc.
c.
Waste Rock PUeslBelden Non-Point Sources
Previous investigations identified 12 piles covering an area of approximately 93 acres
with a total volume of approximately 1,500,000 cubic yards. The waste rock contains
elevated levels of metals which could potentially be released during snowmelt and
rainstorms. Additionally, during late winter and very early spring the data show
significant non-point loading to the Eagle River in the Belden area. approximately
25% of the total Site incr~ase. Non-point source load for that segment of the Eagle
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River ranged from 13 to 191 lbs/ day with an average of S6 lbs/ day for the period
from 11/90 'to 4/91. Eagle River dissolved zinc concentrations as measured at
Station E-S below Belden ranged from 00320 up to.103 mg/l during the. same period
D.
Roaster Piles
Original1y five piles of waste materials from the ore roasting plant were located in
the Belden area. These roaster piles bave been removed from their original
locations and transpOrted to the CIP. Residual quantities of waste material still
remain in some of the areas. Revegetation efforts have been undertaken at several
of the roaster pile areas.
During 199~ the tributary which drains the RP-1 area (Figure 2), flowed at a rate
of 19 to 22 gallons per minute (gpm) during the November to April baset10w period,
. and up to 133gpm during runoff. Zinc concentrations in surface water draining from
the Roaster Piles varied from 29 mg/1 to 43 mg/l during baset10w and ranged up to
76.2 mg/l dwiDg JUDe. Zinc 1(\2~ from the Roaster Piles to the Eagle River varies
from 7 to 30 lbs/dayin the AUgJJst to October period to about 45 lbs/day during
nmoff. Dms, the 1"r'!ftn~ry which drains the Roaster Piles contributes ~'-.3% of the
. . -
total increase in load in the Beidensegment of the Eagle River.
E.
11- FI.a~/Old Tam~ PUe Areas
As a result of mine operations app.u",;...:rtely one million tons of tailings were
deposited in the Old T~i1in~ Pile (OlP) and approximately 150,000 tons of tailings
were deposited at Rex flatS. These tailings have been removed and placed in the
Consolidated Tailings Pile (CTP). Revegetation efforts have been undertaken at
both areas.
The ground water which underlies the OlP area is contaminated with heavy metals.
The OlP occupies approximately 40 acres, and depth to bedrock is about 40 feet.
Assuming a porosity of 25% there is about 400 acre-feet of contaminated ground
water underlying the area. This estimate is uncertain due to lack of information
concerning the configuration of the alluvial/bedrock structure. Testing performed
in wells completed in the OTP indicated that the formation underlying the OTP has
very low transmissivity.
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The ground water which underlies the Rex Flats area is coDt~mina,ted with heavy
metals. The Rex Flats ,area occupies approximately 20 acres and depth to bedrock
is about 40 feet. Assuming a porosity of 25% there is about 200 acre-feet of
cont~mina.ted ground water underlying the area. This esnmate is uncertain due to
lack of information concerning the configuration of the alluvial/bedrock structUre.
Analysis of the metals load upstream and downstream of Rex Flats/OTP indicates
that. the area generally does not function as a source of metals traDSpOn sufficient
to iinpact surface water quality. For each sampling event conducted from November
1990 through April of 1991, metals load through this reach decreased. It is possible
that"during storm events or periods of rapid snow melt that this area still contributes
a net positive increase in load.
F.
Consolidated Tailinl' Pile
The en- covers about 69 acres. Approximately 30 acres (40%) of the pile have been
gm;r.ed with a low permeability cap. A historic pond on top of the pile creates
hy
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sludge which is currently stored on top of the CIP in the historic pond The wet
sludge disposal practice currently employed prevents the capping of the pile from
being completed Water from the sludge maintains the hydraulic head at the historic
pond
The. treated water which is released to the Eagle River is sampled and analyzed on
a routine basis to verify that metals levels and pH are in compliance with the permit
conditions. (The Permit was issued by Colorado Water Quality Control Division).
The plant produces appro'rim~tely 120 to 150 cubic yards of sludge per day. This
sludge contains about six to eight percent solids with the remainder being water.
Pilot studies have been conducted on the sludge and show that the sludge can be
dewatered by filtration to produce a filter cake which contains approximately 50%
solids by weight. This cake occupies about one.third of the volume of the wet sludge.
The cake will not give up free liquids.
VI.
SUMMARY OF SITE RISKS
QU.1 of the Eagle Mine Site includes S11t'fa= water, groundwater, and on-site taiHn~
material. No baseline risk assessment has been' prepared ~ comprehensively evaluates
all potential human health and enviromDeDtal risks. However, there have been a number
of studies conducted that, collectively, assess the major potential exposure pathways for
these media. After full review of these documents, EP A has determined that these studies
provide all the information and analysis that would be necessary in a baseline risk
assessment. Section 3.0 of the Feasibility Study Addendum snmmarizes the key aspects of
these .studies. Below is a snmmary of the findings of these studies as related to this operable
unit. The discussion includes the . following sections: Source of Contaminants and
Chemicals of Concern, Human Health Risks, and Environmental Risks.
A.
Sources of Contaminants of Concern
Sources of Contamination The main sources of contamination for this
operable unit include: the residual waste material at the Roaster Pile Are~
the OTP, the Rex Flats Are~ and the CTP; waste rock in the Belden Area
and along Rock Creek; and surface and subsurface seepage from the Eagle
Mine. These sources have. contributed to contamination of surface waters
(primarily the Eagle River) and ground water. The tailings material and
waste rock may have been a source of airborne contaminants in the past.
.19.
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Cont~nni)1ants of Cnncem The main cont~min~nts of concem (COCs)
associated with the above Doted sources are arsenic, cadmi~ copper, lead,
and zinc.
B.
Homan Health Risks
As discussed above the main con~min~ted media at the Site are surface soils,
ground water, and surface water. A potential exposure pathway of
con~min~tion is human consumption of trout from the Eagle River, which
will be discussed in the subsection on surface water. Airborne metals have
originated from surface materials and this will be discussed in the surface soil
section. The potential for hl1m~n~ to be exposed to these sources of
coDt~min~tion is discussed below along with estimates of ,potential risk. '
~l1rf~r~ Soils Implementation of the Remedial Action Plan (RAP) has
resulted in the removal of the tailings material from Roaster Piles 1-5, Rex
Flats, ami the OTP. This material bas been moved to the crP, which is
being capped and revegetated. The RAP goal is to remove mine waste
, ' ,
material from the raffinv areas and' to reduce residual lead leveJs to below
1,000 ppm lead in sarface soils by removal or isolation. This goal is assnmed
to be p1oh;"tivc of human health for potential future on-site exposures to
,surfa= soils.. Potenri~1 exposure to airborne contamin~ntS is expected to be
minimal becal1~ the Site is being revegetated.
Ground Water There are no current users of contaminated gr'Jund water at
the Site. Although the Town of Minturn bas tWo dr'inlqng water supply wells
located in the aquifer that extends under the crP, regular sampling and
analysis of this well water indicates that it satisfies federal drinking water
standards.
Surface Water The only surface water use from the Eagle River for drinking
water is in the Avon area. The water treatment plant operated in Avon by the
Upper Eagle Valley Water and Sanitation District has been inspected by the
EP A and was found to provide residents a safe water supply that complies
with State and Federal drinking water standards.
It is possible that residents or tourists in the area could consume trout caught
in the Eagle River. Chemicals of concern from the surface- water' could
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bioac:cumu1ate in trout tissue. The Colorado Department of Health (CDH
1992) evaluated the risks from this potential exposure pathway for arsenic,
ca.timium, lead, mercwy, and selenium. The study concluded that no
significant increase in cancer risk was expected and noncarcinogenic health
effects were not expected as a result of consumption of fish from the Eagle
River.
Numerical human risk values calcnJated for the Site' are summarized in
Tables 1 through 3. As a point of comparison, EP A considers that excess
lifetime cancer risks greater than ala-- (that is, one excess case of cancer per
10,000 people) are outside the acceptable range. Note that the excess lifetime
cancer risks calculated for the Site were at a minimum, 20 times lower.
Similarly, EP A has' determined that non-cancer risks approaching a Hazard
Index of "r are unacceptable.
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TABLE VI.!
SDmm_ry or Cancer Risks from InhSlISitioa EXposure at tbe
Mintunl Middle School and the Maloit Park Area(a)
Minturn
Middle Scl1oo1
Maloit Park
Arsenic 8.8xlo-7 3.2xl~
Cadmium 1.Oxlo-7 3.7xlo-7
Chroinium VI 2.4xlo-7 8.5xlo-7
Total Risk l.2xl~ 4.4xl~
(a) a..a CD daD md-
"att by' CoIondo Dep8nmcDt of Health 1990. Refer to tbis report
Cor specific I:ZpJIUftI -.apcioaL
TABLE VI.%
SommSlry of Non-CardDogenic Risks from Ingestioa or
F"1Sh fmm tile EqIe River(a)
Hazard Index for Children(b)
Based on Mean FISh
TISSUe Concentration
Based on M~Yimnm FlSh
TISSUe Concentration
Arsenic
Cadmium
Methyl Mercury
Selenium
0.14
0.01
0.40
.0.05
0.39
0.02
0.81
0.07
(a) Baed CD data aDd risk .. - at by CoIor8do nq,artment of Health 1990. Refer to tbis repon for specific
apoIUI'C aIIUIIIpIioDL
(b) Note that hazard indices for cbi1dren ~ greater than for adults in all c:ascs.induding women wbo arc
pregIWIt or nwsiDg.
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c.
TABLE VI-3
CaDcer Risks tl'Om Potential Release or
.PCBs to the Eagle River(a)
ActivitY
Ingestion of FISh
Children
Adults
&ME Excess Lifetime
~
1.3xl~
l.lxl~
Incidental Ingestion of
Surface Water(b)
7xl(j10
(a) Baled 011 Risk.~ - _t by MoniIaa K&nadIa 1991. Rdcr to
dIiI zepDIC far specific CIIpCII8I8 ....~
(b). 0aIiIII ......c.uiaa8I W8IU IpOII8 sucII . IrayaiIiq aad raftiq.
(c) em:. 1ifcsiIIIecaaa:r ris.k baicd oa R.cuoaable Maximum ExpoAre.
ERvimnmParnl Risks
This section summarizes the potential exposures and risks to aquatic
OI'Vnim~ and terresttia.1 wildlife associated with the souices of CODt~mination
~1~ced in previous sections.
AQJ1Rtic R~tors The main environmental concem at the Eagle Mine Site
is the poteT1rial for adverse effectS to aquatic organisms in the Eagle River.
The Colorado Division of Wildlife conducted stUdies on the Eagie River
fishery in 1990, 1991 an~ 1992 in we river. These studies are the best
available information on the statuS of potential aquatic receptors. The DO W
collected fish, aquatic invertebrates, and water quality data in April and
. September of 1990 in the Eagle River from Redcliff to Arrowhead; and'
collected fish and water quality data in April 1991 and 1992. The conclusions
of these assessments state that heavy metal concentrations (cadmium, copper,
and zinc) in the Eagle River from Belden to Minturn are above levels that are
acutely and! or chronically toxic to some trout species. In addition, the fish
and aquatic macroinvertebrate communities are severely reduced in this reach
of the Eagle River. In 1992, cadmium exceeded the Colorado Water Quality
Standard (CWQS) for the Eagle River at DOW sampling stations from
Belden to Minturn. Copper was elevated in 1990.but dropped below CWQS
in 1991 and 1992. Zinc concentrations were greater than up ~o 4 times the
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CWQS. Zinc also exceeded the DOW criteria for acclimated brown trout by
up to approximately 6 times. . Total zinc concentrations were higher in April
1991 and 1992 than they were in April 1990. The chronic CWQS are listed
in Table WeB.
~ For wildlife, potential exposures to COCs in surface
soils are assumed to be elimin!lted by the removal of tai1in~ material from
the source areas described previously. Thus, no significant exposures to
surface soils are. expected to occur in the future.
There are no known ground water exposure pathways for wildlife in the area.
Wildlife could be exposed to conrnm;rtants in surface water if the river water
is used by them as a source of drin1dng water.' Wildlife that consume fish
could be exposed to COtltaminants that may accumulate in fish tissues. This
pathway is CWTently limited because of the low bioa('("nmnlanon potential of
the COCS and the low fish biomass in the river.
~ or threat~~ re1easesof hazardous S~tadces from this Site, if not
addressed by implementing the response action selected in this ROD, may
present an ;mIH;.1eUt and substantial endaDgermem to public ~Jth. welfare,
or' the environmf!nt
vn.
DESCRIPTION OF ALTERNATIVES
The Eagle Mine Site is a complex, multifaceted site. A vast array of data and technical and
regulatory analysis has been developed in key documents which have preceded this decision.
This Record of Decision cannot provide the level of detail offered in those earlier
doaunents. For that reason a list of the doaunents employed in the decision-making has
been provided in the Appendix following the Responsiveness Snmmary. Given the
complexity of the Site, the S11mmary of the description of alternatives provided below may
warrant referral to those documents.
.
A.
Develooment of Remedial Action Obiectives and Goals
Prior to developing the alternatives, remedial action objectives and numerical
cleanup goals were framed consistent with 40 CFR 300.430( e )(2)(i). The objectives
and numerical goals were framed in consideration of the Site characteristics which
have resulted from the continuing remedial activities, the resillts of the risk
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. .
assessments performed at the Site, and the results of evaluations of legal Standards
and requfrements which are either applicable or relevant and appropriate to the
remediation (ARAR). In addition to ARARs, other information, known as "to be
considered" (TBCs), which proved useful to establishing Site objectives and goals
were considered and are summarized below.
CERCLA. as amended by Section 121( d) of SARA requires that remedial actions
attain those standards which are ARAR to the Site. The universe of laws, standards,
regulations, and criteria initially screened as potential ARARs were presented in
Appendix B of the FSA The potential ARARs were further evaluated in Section 4
of the FSA in light of Site circumstances and the selected ARARs were presented.
The ARARs were divided into three types: contaminant specific, action specific and
location specific. Typically it is the cont~minant specific ARARs which are germane
to the development of objectives and goals. In contrast. action specific and location
spe("ific ARARs typically create constraints on the remedial alternatives. For that
reason, the cont~minant specific ARARs will be summarized in conjunction with the
remedial aA:tion objectives and goals, while the action and location specific ARARs
will be sw::nmaiized, where appropriate, as part of the description of each alternative.
The selected \;ou",.,II;IIAl1t specific groundwater ARARs for the Eagle Mine Site are
presented in Table Vll-A. The site-wide chemical specifU: ARARs are summarized
in Table X-l and the action and location specific ARARs are snmm3riZed in Table
X-2 in this document. .
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TABLE VU-A
CM"'-......t SpecUk GroaDd Water ARAlb at the
EaaIe MIlle SIte
CITATION
Colorado GftR1114 Wau::r SWuI-da. SCC1l1002-8, Sedjon 3.11
~JBST ANTIVe RFntJlREMEN'l'S
Res FIara GI01IIId WaIer.
Rdcv:mI aad 4t'~opliar.e for ,.1..cciG_rinn as aaaa 3 - Protcc:tioD of Surface Wau;r (sccrion
3.11.4(B)(3». See Table VB-B for the DIIIDCrica1 values.
Old TailiDp PiJc Grouad WaIer.
RcICWDI - 4t'paOplWe for M..uin~rinn as Cass 5 - T j",itf'.d Use and Quality (scc:tion
3.l1.4(B)(S». No ARARs were id-riGcd for the CJaaa S ground water.
Ma10it Park North of Cross Cn:ck Ground Wau:r:
RdcvaD1 - "t'!,&09fWc for cl3ssificatioa as Oass 1 - DomCS(ic Use Quality (section
3.l1.4(B)(1». The 1IDIDC1ica1 values for the roncri~ of ~J1 iadudc:
ArscDic -
C~mm -
ChroIIIium -
Lead -
Mcn:ary -
S04/l
101I8/l
SOI&g/1
504/1
2 11811
Grouad WaICr BG...catb tile ~ TaiJiap Pile:
Rc1cYaDt aDd appauP&~ for ..I.._...:fiq"""" as Cass 4 - ~ Usable Quality (secrioD
3.11.4(B)( 4».
Arsc:Dic -
Cadmium -
Chromium -
Lead -
Mercury-
50411
10 1£811
501&811
501&811
24/1
Ground Wau;r Adjaa:D1 to the Eagle River:
Rclcwnfmd appropriate as Class 3 - Protection of Surface Watcr (section 2.11.4(B)(3». See
Tablc VB-B for the numerical values.
.
[[[
The different source areas of the Site contain a varicty of groundwater regimes with potcntially diffcring
groundwater classifications. These areas have not been formally classificd by the State of Colorado, and for that
reason EP A evaluated thc characteristics of the groundwater regime, evaluated the Colorado requirements and
-------
The EP A considered surface water quality ARARs and a variety of other to-be-considered
(TBC) information when fr-Iming the remedial action objectives and goals. These TBCs
included both the water quality criteria developed by the Colorado Division of Wildlife
(DOW) and the water quality goals established in the Re~edial Action Plan (RAP) and
adopted by reference in the Consent Decree.
The Colorado Table Value Standa1'Cis (TVSs), as the relevant and appropriate criteria at the
Site, are adopted as the surface water quality Fmal Remediation Goals. There are several
reasons for this selection:
rust, the statUtory language of CERa.A specific:ally includes the Federal Water
Quality Criteria (FWQC) in the universe of ARARs where those criteria are relevant
and appropriate. For zin~ the Colorado 1VSs are equivalent to the FWQC, and for
other metal constituents the Colorado TVSs have been established using the FWQC
protocol
Second, the CWQD cl~~~fication for Segment 5 of the Eagle River and the segmentS
i1n1'nMfiateJy upstream and doww.treaD1 of the Eagle Mine Site are all Oass 1, cold
water aquatic life. EP A concurs that the designated Class 1 cold water aquatic life
use for Segment 5 is appropriate and that it reflects an attainable condition. TIie
CWOD M~cm;carinn of Segment 5 has been iip1X
-------
of Segment S as a Cass 1, cold water aquatic life, the EP A believes that the Eagle
River surface waters "are intended to become suitable for such uses" as prescribed
by Section 3.1.13(1)(c)(i), and that the TVSs are' relevant and appropriate to those
uses. (Also see 3.1.16 (1) and 3.1.7. (l)(b)(i)). "Ibis conclusion is inherently
consistent with the. structUre of the Colorado regulations, until such time that the
Commiqion formally redefines the DatIlre of the aquatic community being protected
and the numeric standards required to protect that redefined aquatic community.
The selected conrnrmnsmt specific surface water ARARs. for the Site are presented
. .
in Table VII-B. .
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TABLE VII-8 .
Coatsaminsant Speciftc Surface Water ARARs
. at the Eagle Mille Site
crrAIIml .
Colorado. Water Quality Standards. SCCR 1002-8, Section 3.1.7, Table ill, Table Value
Standards. (TVS). .
Standards apply on a year-round basis.1 Hardness is assumed to be 100 mg/L 2 Standards
are not to De exceeded more than once every three years on average~3 The relevant and
appropriate chronic surface water standards for cont~min~nts of concern include:
Zinc 106 ~g/l (dissolvedt
Cadmium 1.1 ~g/l (dissolved)~
Copper 12 ~g/l (dissolved)"
Lead 4.0 ~g/l (dissolved)4
Silver 0.08 JJ.g/l (dissolvedf
The relevant and appropriate acute surface water standards for cont~min~nts of concern
include: .
Zinc
C~dmium
t:'r
Silver
117 JJ.g/l (dissolved\6
.3.9 JJ.g/l (dissolved)
18 JJ.i,/1 (dissolvedt'
96 JJoiI1 (dissolved)6
.2.0 ~g,tl (dissolved)6
1 The samdards appiy on a ve:D'-rnund basis. (See St-l'rinn 3.L9(1».
% HardaesI js ,"U11ft1..d to be 100 mg/1. A 6Da1 dc:~miDationof the Si£e-speci.6c 41UIIcrical ARAR values for
each of the listed mcraIs wiD require .appli..,.,;on of FooamtC (2) to Table m of the Basic Standards. (See
FootIIOte (2) to Table m of the Basic Standards and Meth~ for Surface Waters, 5 CCR 1002-8,
SCdioB 3.1.16). . .
J Standards are DOt to be u~ IDOI'C tbaD oaa: every three years aU average. (See Footnote (4) to Table
m of the Basic Standards and Methodologies for Surface Waters, S CCR 1002~, Section 3.L16).
. Chronic Table Value Standards. A cbronic standard is that level Dot to be exceeded by the concentration
for either a sU1gle re~"r::lrlve sample or caic:ulated as an average of all samples collected during 3O-day
period. (See Section 3.1.5 (7». Also DOte that the chronic standard is implemented in combination with a
se1err...d dDraIion and frequency of recum:zu:c. (Id).
, The c:bronic Table Value Standard for silver employs the Table Value Standard specific to troUt. Otherwise
the conditions outlined in. footnote 4, above, apply.
.
6 Acute Table value Standards. An acute standard is that level Dot to be exceeded by the concentration in a
single sample or caic:ulated as an average of all samples collected during a one-day period. (See Section 3.1.5
(2). Also Dote that the acute standard is implemented in combination with a selected duration and frequency
of recurrence. (Id).
7 The acute Table Value Standard for cadmium employs the Table Value Standard specific to trout. Otherwise
the conditions outlined in footnote 6, above. apply.
EalPe Mine Remedial Action Objectives and Goals
The general remedial action objective~ and where applicable. -the numerical- goals for the
Eagle Mine Site are presented In Table Vll-C. . .
-29-
-------
TABLE VU..c
General Remedial Action Objectives aDd F"mal Numerical Remedial
Amon Goals for the Eagle Mine Site
'v Final Remedial Action. Goals
Improve the quality of water in the
Eagle River to support Class 1 aquatic
life use;
Conttol or eliminate human ingestion
of CODtaminated ground water;
Control or eHmina,te exposure to
airborne ~nnnants;
Contr{)l or elimina.te exposure to
contaminants in soil;
Zinc
Cadmium
Copper
Lead
Silver
Arsenic:
Cadmium
Chromium
Lead
Mercury
Chronic
106 Jl-g/11
L1 Jl-g/11
12 ",g/l I
4 ",g/ll
0.08 ",g/11
SO",g/l %
10",g/1 %
SO",g/I%
SO",g/1 %
4r.g/12
Acute
106 ",g/1 S
1.1 ",g/l S
12 ",g/l S
4.0 ",g/l S
0.08 .ug/l S
Total Suspended Particulates
Lead
Lead
. .
13S .ug/ m3 3
1.5 ",g/m 3
1000 mg/kg 4
Ensure the long term integrity of
stmc:tures and facilities associated with
remedial activities at the Site.
Chnmic: Coiorado TVSs as die .~y~ aDd appropriarc 9!awviards., Dissolved
conccnttarioDS. If the classific:aJion for Segmcm 5 of the Eagle River is changed or the
CWQSs are updated to refIcc:t the results of the remediation. those new standards
could be adopted as the final remedial action goal at the five-year review.
ldenrificarion of specified gJ'OUDd water areas, classifications, and goals based upon the
Colorado GroUDCi Water Standards. The goals presented here are ARAR. for C1ass
1. DomeStic: Use-Quality gJ'OUDd water. For the Class 3. Surface Water Protection
gJ'Ouud waters the goals for surface water quality apply.
z
3
Based on CI'P construction air permit conditions as To Be Considered criteria. Concentration
in air over a 24-hour period. .
Based upon Interim Guidance on Establishing Soil Lead CleanuD Levels at Suoerfund
~ (Septcmber 1989). Surface soils > 1000 mg/kg are removed. Surface soils> 500
mg/kg but < 1000 mg/kg are treated with lime.
Acw:e Colorado TVSs. as relevant and appropriate standards. Dissolved
concentratioDS. If the classifiCation for Segmcm 5 of the Eagle River is changed or the
CWQSs are updated to reflect the results of the remediation. those new standards
could be adopted as _the final remedial action goal at the -f?;vc-ycar review.- -
s
-30-
-------
. .
Be
Dest!riUtiOD of 4.Itematives
The goals in developing the remedial alternatives were to prov:ide a range of clean
up options with sufficient detail to adequately compare alternatives. The alternatives
developed for the seven sources of cont~m;n~tion are as follows:
~
The remedial action objective specific to this source of conrnm;nation is to: reduce the
traDSpOrt of metals in both surface aDd subsurface mine seepage so that F"mal Remediation
Goals will be achieved in the Eagle River. Four remedial action alternatives were defined:
L
NO ADDED ACI'ION .
The mine workings have been flooded to reduce the formation of acid and
thereby reduce the generation of contam;n~ted water into the Eagle River.
There is limited evidence, althougJ1 DO dear tren~ that this "passive
. ~atm'W4r approach is working. A su~nri~) porti,on of the surface seepage
£rom the mine is being collected and tre3te.d. However,.the uncollected
. .
seepage, mostly in the colluvial area of Rock Cree~ is the major source of
m~t~l~ lo~mng to the river. At the present the rime, the Fmal Remediation
Goals are not being a.tt~;ned in the Eagle River.
II.
EXTRACT /COlLEcrfTREAT /MONITORING
Alternative n is the same as Alternative I but adds: the collection of the
colluvial seep water in Rock c;reek using extraction' wells; pumping to the
existing collection system; conveyance to the water treatment plant; water
treatment; and continued monitoring. The discharge from the water
treatment plant is subject to NPDES permitting and ultimately must meet
water quality ARARs, Management of the water treatment plant sludges is
discussed as part of the description of the water treatment plant,
Ill.
SUBSURFACE/SURFACE COlLECTIONfTREATMEl'lT /MONITORING
In this alternative, tWo gravel-filled trenches with perforated pipe along the
southern side of Rock Creek will collect subsurface seeps emanating from the
hillside beneath the mine. Existing prominent surface seeps would be
collected in three.-foot diameter vertical collection pipes, (hermed on the
-31-
-------
IV.
upstteam end of the drainage to preclude entrance of surface water except in
large storm events). Eac:h ttench discharges to the existing seepage collection
box near the confiuence with the Eagle River, where seepage would be
pumped to the treatment plant. The discharge from the .water treatment plant
is subject to NPDES permitting and ultimately must meet water quality
ARARs. Management of the water treatment plant sludges is discussed as
part of the description of the water treatment plant.
SUBSURFACE/SURFACE COLLECI'ION /TREATMENT/CLEAN
WATER DIVERSION/MONITORING
This alternative includes Alternative m and adds the diversion of surface flow
in Rock Creek upstteam of the impacted ~ea. This addition minimi7.es the
volume of clean water CODt~min~ted by subsurface flow from the mine works.
The diversion of the creek will be ev~Jn~ted under the FISh and Wildlife
Coordination Act to determine if impactS will require mitigation measures.
The discharge from the water treatment plant is subject to NPDES permitting
and ultimately must meet water quality ARARs. Management of the water
treatm.ent plant sludges is discussed as part of the description of the water
trea~nt plant.
Table VU-D illustrateS each altemative for this source area.
-32-
-------
Eagle Mine Seepage
Characteristics:
Curren' zinc concenlration,
range from 60 '0 \00 mg{1.
Surface flow In Rock Creek
ond ossoclaled subsurlace nowe
represent the principal source
a' metal loading, contributing
40" - 601 01 the 'otol.
Eallmo'ee lor the bosenow
r.erlod 01 \99\ place the
oodlng from Rock Creek seeps
between 35 to tJO Ib/do)' 0' line.
Ob Jee Uves IGoals:
Reduce the ,transport 01 melols
In both surloce and subsurface
mine seepage.
The Final Remediation Goals
'or the Eagle River orll
based upon thll Colorado
TVSs 05 ARARa.
Tobie :2II-O
Alternative I ' Conveyance to '
Existing Treatment Monitoring
Continued Sur'ace J Plant 7
Seep Collection . Collection o' eurfdce water ee .
Alternative I I , Treatment ' Monitoring
Includes Alternative I -~ 7
~'us Extroctlon of
olluvlol Seeps . Pumping to .,.I.tIn9 collecllon .
. Sur lace Ditches ond Piping
reducee th. volume of m.t~e p
tron,pOlt,d 10 Ut. £ogle River
. Treatment d. 70 IIpm
. Ot!ee not addle.. .ubsurloce eeep'
. NPDES Permit relJllred
. [.nuent treatm,nt to achieve
~,rm" .tandard.
. Effluent eaU.nel BAT
. 4 Exlroctlon Well.
. Surface Dltchea and Piping
.ptem
. Reduce. ma8' 01 cpntomlnont.
entering the Eagle Rlvir
. Treats lurface Clod sub sur lOCI
aeepage
. NPDES Permit rlqulffd
. ['duent latl~h's BA
. 'Elduent \rea ed ochlev.
pe,mn . 01\ drdl
Alternative I I I , Treatment
Includes Alternative I ~
plus T08 Drain at 80S8
ot Rock Creek
. Two toe drains along soulh
side (II Rock Creek
. Each trench discharge 10
the IlIls, tlng lIOepog' collecllon
box near ihe conlluence of the
Eogl, Rlvqr
. trlotment 0' \20 gpm
. Aeducea moss of conlomlnanl.
.nierlnll ,the Eoglo Alvor
. NPOES Permit r.qulred
. [Ihuenl \reated to achieve
permit IIlondardl
. £fRueni saUsnes 8A T
[- ~--~
Allernative I V
1ncludes Aliernatlve III -- Treolrnent ,-
pius Upgradlent Diversion ---.------
ot Rock Creek . hemoves 'contamlnonls b~
- collecllon and !reolment thus
. Two lac drains 05 In ,educing the moss of COlllufllinonis
Alternallve III delivcred to Ihe [ulJle IUver
. Olver I Hock CIcek surface now . Trealmenl of \20 !jprn
. Heduces volume 01 conlulflinoled . Nl'n[S Pc, ",It required
woler reqllirinylrculmclII . nOllcnt II culed lu uthicve
pm!llil ~IIIIIIIIII <1:1
. Reguior .et .ampllng
. Sample [a e RlvOl otiOV8
and below ock CI,ek
Rlguior aet lampllng
. Sample £0 e RlvOl ObOV8
and betow ock Cleek
~
Monitoring
. Regular seer. lampllng
. Sampll £Ogll RIver above
and below Rock Creek
f
Monitoring
. Regular seep eompllng
. Sample fagle River obove
and below Rock Creek
. Rapid Impltml:ntab.lt,
. Capitol Coel, 0
. Annual 0"" 11250
. Plesent Wor\h, \25,481
(based on \0 )'11011 r.,
51 dlscounl "11.\
. Cosl for water Ifldtmont
Included 01 Tabl. m-J
. Implementobl., Iqu!P.ment
and malerloll avola6le
locoll,
. Capital Co.t, 12J,681
. Annual 0"", 10.656
. Plesent Worth, 1\01(438
(baled on \0 )'liar I f.,
51 dlscounl roll\
. Cost for woter Ifedtmonl
Included 01 Tobll m-J
I
. Implemented b, conventional
construction technIque..
some dllf1cult, ma,b'
encountered
. Capitol Coat. 111}1J
. Annual 0"", 'to,150
. PIesllnt Worth, 1192(1J4
(based on 10 )'liar I '1,
51 discount rotl \
. Cosl for water .rldtmont
Included at Tobll m-J
. Implemented b, convontlonal
conslructlon technIque..
some difncult, ma,b'
encountered
. Capitol Cost, '121,950
. Annuol 0..... \ 1530
. Present Worth, 126J.Jt1
(based on \0 year IIfl,
5~ discount rote\
. Cosl for water "e6'menl
Included ot Table m-J
-------
w
The remedial action objective specific to this source of contamination is to: reduce the
traDSpOrt of metals by iDfiltr2tiOD and surface water runoff' so that the F'mal RemediatioD
Goals will be achieved in the Eagle River. Four remedial. action alternatives were defined:
L
n.
NO ADDED AC110N
There are tWelve waste rock piles on the cliff faces betWeen Gilman and the
Eagle River. These piles, which came from mining activity, cover
approximately 93 acres but their exact thickness is unknown. To prevent
surface water run-on, clean-water diversion ditches have been constructed
upslope of 11 of the piles. .
MONITORING OF SURFACE/GROUNDWATER FROM EACH
WASrE SOURCE
This ~Mive i1'dl1M~ the installation of a series of monitoring wells near
- toe of the waste rock piles plus automatic stOrm sampling stations at
appropriate drainage locati'?DS. Sampling and testing of the groundwater and
surface water would be conducted on a regular basis to determine the amount
of metals lo:ading attributable to the waste rock piles.
m
PARTIAL REMOVAL OF WASrE ROCK Pn..ES WITH ONSITE
'DISPOSAL
This alternative consists of removing and disposing of all the waste rock piles
that are located betWeen the base of the lower cliffs and the railbed through
Belden. This option would include recontouring underlying sediments, limited
bacJcfil1ing and revegetation of lower slopes. Waste rock would be placed at
the current location of the historic pond in a reconfigured crP.
IV.
TOTAL REMOVAL OF WASTE ROCK Pll..ES
This alternative consists of removing and disposing of all the waste rock piles
that are located on the Site betWeen the Eagle River and U.S. Highway 24
and disposing them at the reconfigured crP. This would include some
recontouring and revegetation.
Table Vll-E illustrates each alternative for this source area.
-34-
-------
Waste Rock Piles
Characteristics:
Wel wealher transporl 0'
. conlamlnanl. 10 Ih. (agl. River
Previou. Invesllgallon. Identified
12 pica covering on areo 0'
opproxlmolcl~ 91 acres wllh a
'0101 volume 0' approxlmalely
1.500.000 cubic ~d.
Non-polnl zinc loading 10 Ih.
[ogle River In Ihe Beldon
oro a represen" 10-JO"
In lato wlnler and eorl~
spring
Alternative I
"0 added
action
. Accepl. Impacl. 10 the Eogil
River trom Ihl non-palnl .ourcel
n Ihl. orca
Table ID-E'
Alternative II , Surface Waler " Groundwater ' Leach
Monitor Sur 'ace ~ "'onllorl*'g / Monitoring ~ Testing
and Groundwater
. Aulomatlc: Itorm wcslar runoff. . .
. To Idenllfy primary louree areal
releasing conlomlnanls of concern
. Will nal old In Ihe reduction
of loxlclly. mobUltyor voIum.
Alternative III
Partial removal
o' lower plies
wllhln onslle dis 0901
Non-point source zinc load lor thai. Consists 0' removing and
segmont 0' Ih,e £aglo River disposing all Iho waslo rock
longed 'rom U 10 1911b/day plies Ihat are localed bel ween
with on overage 0' 56 Iblday Ihe base 0' Ihe lower clilfl
In slream zinc concentrollons and Ihe railbed through Beldon
longed 'rom 0.32 up 10 1.3 mgjl during
November Ihrough Apr. In 1991.
Ob Jecllves/Gaals:
Reduco Ihl trp'nsort 0' melols by
InnUroUon and surloce waler
runoff.
Tho final Remedlollon Goals
'or the Eagle River
are based upon Ihe Colorado
TVSs as ARARs
Alternative IV
Tolal removal 0'
wasle rock piles
with onsite disposal
. Conslsls 01 removing and
disposing all Ihe wasle rock
piles Ihat are localed bel ween
Ihe [ogle River and U.S.
IIwy 24
.ompllng Iiolion.
. $qmpliB placed Iri drlllncigi.
dllc:l\OI Gnd channell k\ .0.11
rock pl'l
. Automatic fur'oCO .amplng 01
.tarm even .
Excavation
. 500,000 cubic yarde
. Lllnlng and eorlh momg
equlpmenl required
~
Excavation
. 1,500,000 cubic )'Irds
. Uinlng and earlh moving
equlpmenl required
. Exlended period olUme
duo 10 'sarel~ conslderalions
WoIlI p'!oced bet.een wall.
Jack p'10I and tho (ogle River
. Well. 10 bl .amplld Cflortll1~
DIsposal
. Dispose at Iho reconfigured C1P
. Tran.ported by tron
. 8evlll excluded walt..
.~
Disposal
. Dispose 01 Ihe rDconfigured C1P
. Transported by train
. To dispose entire volume 01 waslo
rock 01 cn' would require ulenslvo
redulgn .
. De..;11 exChHJ~d wasles
leach te.t. on VQllet~
o' wosle material.
pre,ent In th. pie.
RlcontourlnD "
" Reveg.ta on
Recontourlng "
" Revegetation
. prevta~. Ac:tll¥\ In!ded
run-f dlverllOn 0'4
no. wa.~ I p'.'
: ~C~~ Bu.~' 18
. Prelent Wortn. 10
. Implemenlabl.. equ~ent
and molcrfoll Gvolatil.locaI,
.. Copllol COlt, 188.(000
. Annual OW 11~,IIOO
. Presenl Worl~ '188.000
(based on 10 ~or ""
51 dl.count lal.)
. (.tremlly dI'ftcuit 10 mpllment
. Specialized eCUl!Pment nllded
. Copllol Co. I. IUIt.~ .
. Annual OiU VOIr frCl!' 0.000
lor Iho tal )'1101 to IJ.
Ihe 5th )1101
. Presenl Worlh 19.423.000
(baaed on 10 )'101 1110.
51 discount lotl\
. Call highly uncer(aln
. Slgnlficonl ahorl-term
envtronmenlallmpact.
. Exlremely dlfflcullio Implemenl
. Specialized elll!Pment needld
. Capitol COlt. 117.933.000
. Annual OW vOl~ fr~ II80.00c
'or the tal year 10 110,Mo
Ihe 5th )1101
. Presenl Worlh 128\268,000
(based on 10)'101 110.
51 discount rote\
. Cosl highly uncer(!ln
. Signlficanl shorl-lerm
envtronmenlallmpocll
-------
~
The remedial action objectives specific to this source of contamination are to: 1) reduce the
surface water transport of metals from the ares of Roaster Pile 1. and .associated drainage
so that F"mal Remediation Goals will be achieved in the Eagle River, and 2) ~tablish
veget9tiOD to a natural condition. Four remedial action alternatives were defined:
L
NO ADDED AcnON
This alternative leaves the remains of the roaster piles in their existing
conditions with the prospect that the revegetation efforts previously attempted
will .be successful in controlIing the levels of metals discharged to the Eagle
River via surface water runoff. This alternative also includes regular
monitoring of quality of surface water in the drainage to determine the
effectiveness of the revegetation efforts.
n.
COlLEcr /mEAT /MONITOR
This alternative includes: the constrUction of a small collection sttUctUre
(intake dam) at the base of the drainage; the constructiQn of a small diameter
. pipeline to collect and convey the 20 gpm base flow to the existing collection
system.near Belden with subsequent deHvety of the contaminated water to the
water treatment plant. Monitoring ofwate1' quality in the drainage is included
to determine whether water quality iw.proves. The discharge from the water
treatment plant is subject to NPDES permitting and ultimately must meet
water quality ARARs. Management of the water treatment plant sludges is
discussed as part of the description of the water treatment plant.
m.
LIME mEAT jTOPSOll../REVEGETATE SURFACE
This alternative consists of lime treatment of the existing soil, covering the
roaster pile areas with approximately 12 inches of imponed topsoil and
revegetating the areas. Monitoring of the water quality in the drainage will
also be required to test the effectiveness of the topsoiling and revegetation.
IV.
COu..Ecr;'TREAT /MONITOR-LIME TREAT /TOPSOIL/REVEGETATE
This alternative combines the collectio~ treatment and monitoring outlined
in Alternative II with the lime treatment, topsoiling and revegetation of
Alternative III
Table Vll-F illustrates each alternative for this source area.
-36-
-------
I Roaster Plies I
Chorocterls'lcs:
The original 5 plies have
been removed
Tributary "owed at a rate 0'
19 to 22 gpm during '99'
baseftaw season
Zinc concentrations varied
from 29 mg!1 to .u mg,l1
during basenow, but ronged
up to 76.2 mg{1 during Junl
Contributes 2-3" 01 total
metal loading
Ob jedives/Gools:
Reduce the transport 0' metals
by surface water and re-establish
vegetation 'to a natural condition
The final Remediation Goals
for the Eagle River are
based upon the Colorodo
TVSa aa ARARa
Allernatlve II ' Trealment ' Monitoring
Collect, Treat, -, ,
Monitor
. fte utor 10m Iin 0' aur'a
" Treat with lime ,I Reve~etatlon/
Allernatlve III 7 and Topsoil -, Monl orlng
Revegetate, Monitor
. lime elClltin soli to . Mulch blanket stabUlzaU
Tobie ID-F
Alternative I ' Monitoring
No added action '
Monitor
. Leaves RP , In existing
condition
. Assumes revegetation .111 be
luccessfut
. RlgulQf lampllng 0' aur'ace
woler In dralnoge
. Intake dam at base 0'
drainage
. Treotmlnt o' obout 20 gpm
bosellow
. NPOES Permlt.requ".d
. ['Duent trloted to TVS 01
ARAR
. [fRulnt 101l8nOl BAT
. Operot. during ba.eflow
period
. Topsoil, elCpedlte revegetation
. Prevents storm water contact
with contaminated materlols
9
reduce acid lormlng potential
. Dllllcult to tOPfoll given
slope ond presence of
boulders
J-- t~:I~~~,a:~~~:."-J' .-..----.
Monitor
----.----
.- . Regular sampling 01 sur loce
waler In dJ 01lluge
[--
Alternative IV
Combination 0'
Alternative 11 and
Alternative III
g p g
woler In dralnagl
c.
/
on
. Regular sampling 0' surfac.
woler In drolnoge
. 5 )'eors to demonstrote
substantial revegetation
Alternative III
Topsoll/
Revege\ate
. Mulch blanket/stabilization
. Regulor sampling 0' surface
waler In drainage
. 5 Y':urs 10 .lel11o"slr~te
. Extenalve removal cOfIducted
. Added Copl~aI COlt, 10
. Annual 0"", vorw f,om
'20,000 'or the'lt )'ear to
.000 the 5th nor .
. Pfelent Worlh, 168.9OQ
(Dosed on 10 ~or'lIIe, 51
discount foteJ
. Implementabl., equlP-mlllt
and material I avo.util. to
complete Pllle,ln.
. Capitol Cosf. 6,050
. AnnuolOIdA 7425
. Present Wor\h. 16J.386
(based on '0 wear lIIe 51
discount rote)
. Cost 'or water trootment
Included at Tobie 1lII-J
. MarglnollW ImP.lementablf, ..rprnent
anef molerlOJa avo.oble
. Conventlonoll~d.cop.
. Copltol Coat, 1112.000
Annual OIdA, vorw rrom
f20,OOO for the 1It )'IIor to
,000 the 5th )'I!or
. Plesent Worth. 82J9,ooo
(based on 10 }lOor life 51
discount ,ot8) .
. Marglnallw Implementabl.. equlpmenl
ond molerlols ovoUoble
. Capilol Coat, IU8,000
. Present Worth a. OIdA
'or 10 ~or period, 194.000
. Present Worth. 1212,000
(based on '0 ior life 51
discount rate
. Cost lor water reotment
In dUlled ot Table VI1-J
-------
The remedial action objective specific to these' areas is to: reduce the surface and ground
water traDSpOrt of metals so that the Fmal Remediation Goals will be achieved in the Eagle
River. Two remedial action alternatives were defined:
L
.n.
NO ADDED ACI10NfUSE RESTRICI10NS
The state has overseen the removal of the t~mn~ material from these tWo
areas. This waste material is now in the CTP, although residual tailings and
metals in soils remain. This action has been largely success~ however there
is some concern ovet: spring runoff froni snowmelt from both areas and the
success of revegetation in the south end of the Rex Flats area. Restrictions
on wen drilling, deed resttictions and zoning will be used to control ground
water development in both areas. Monitoring will be continued to determine
whether additional measureS (i.e.. additional soil removal and COI1r~min~ted
. water collection and treatment) are needed.
USE ~cnONS/ ALTERNATE WATER SUPPLY/STORM
WATER SAMPLING
T1Ds altemative prohibits installation of cWnking water wells and, if necessaty.
requires a domestic water supply for future residents and recreational users.
The source of domestic water supply could come from the Town of Minturn's
110,000 gallon water tank which is located on a bluff south of the Middle
SchooL
Table Vll-G illustrates both remedial action alternatives for this source area.
-38-
-------
Rex Flats/OTP
Characlerlsllcs:
Tho groundwoler which
underlies IhD OlP and
Rell rials area Is
canlomlf\aled wllh heavy
metals
OlP occuplu
approxlmblely 40 ocros,
deplh 10 bedrock Is 40
'1101. Wells drUled 01 IhD
On) produced very
limited waler and 'ar Ihal
rDason OlP groundwalDf
Is Closs 5, IImlled USD and
quality
Rell flols occupies
approxlmalely 20 acru,
- deplh 10 bedrock Is 40
'eel. Groundwaler
benealh Rex flab Is
Inlerconnecled 10 IhD
£ogle River ond lor Ihal
reoson Rell flail -
groundwaler Is Closs J.
sur/ace waler prolecllon
Db JecUvesjGoals:
ReducD IhD sur'ocD and
groundwaler Ironspor I
0' melals
TIle final R~l11edlolion Gools
'or Ihe (01)10 Rlvu ore b«,1scd
upon Ihe CCJlorodo Ms
as AUAIb .
Alternative I
USQ Reslrlctlons
. AllenuoUan will
evenlually reduco
Iho limited
conlomlnallon In Iho
oroa
Alternative II
Use Reslrlctlons
and ollernqle
waler supply
. AlienuoUon wUI
ovenluallv roduco
Iho limited
conlomlnollon In Iho
area
1 USB Hasl,lelions ~
. Roolrlcl drilling 0' well.
Inlo contomlnaled aquifer
. Oetid reatrlcUan.
. Municipal or counly
zoning
Use Reslrlctlons
. Roolrlct drilling 0' wells -
Inla contomlnalod oqulfor
. Doed rootrlcUanl
. Municipal or county
zoning
Tobie ~-G-
Monitoring
. Sampling and toallng 0'
.toflnwaler run-oil
Alterl)ote Water
Supply
. Polentlal action dependent
upon 'ulure tand
uso
. (mpl0)'f th. Town 01
Lllnlurn s 110,000
gallon woler ank
. In8l01l0Uon 0'
opprolCl,nalely 6000 linear
leel o. 6-lnch dlomoler
pipe
. Inslollallon alan. I1r.
h~ran'f'\ and a low head
pump D ollon
. £olly ImPlem;nlOd
. Copltal COlt, 0
. Annual OW 2 000
. P/esenl War\h, 115.400
(based on 10 VOOlIlf.,
51 dlscounl ,ot.)
Expedited
Re\tegetollon
t.fonllarlng
. 5 )'8ors 10 demonslral. . Sampling and luting o'
subslonllal ,ovogolallon .IIlIm841u run-all
. Implllllentobl., .quk
and molClIaI. owlob
complel. P1ll11n.
. Capital Cosf; 26~~
. Annual OW 2 tJU
. Pluent WOIbi,I28t,I
(baled on 10 par III
- dlscounl 101o)
-------
The remedial action objectives specific to this source of cont~mination are to: 1) reduce the
surface and groundwater transport ot metals so that the F"mal Remediation Goals will be
achieved in the Eagle River; 2) to control potential human ingestion ot ground water
C:ODt~1ftill~~ by metals from. the consolidated tailings pile;' 3) control potential exposure
pathway to m.iDe t~i1iIlr;a; and 4) control exposure to airborne CODtg1ftill~lIts. Four remedial
action alternatives. were defined:
L
II.
NO ADDED AcnON - CAP All. BUT HISTORIC POND
The RAP provided for e1imination of the historic pond on top of the CTP.
Reducing this hydraulic gradient would decrease the leaching and trimsport
, of metals within the pile to ground water. In addition, the pile was to be
, .
completely ~ped to reduce infiltration of rain and snow melt through the
tailings. The CTP is now 40% capped. Currently, the wet sludge (6-8%
solids) from the WTP is being placed in the historic pond located on the CfP.
This altemative assumes that the wet sludges will co~tinue to be disposed in
. the historic po~d. It also assumes that the historic pond will not be drained
and the cap. will not be completed, because wate~ treatment sludge will be
generated indefinitely, and because no option has been identified for sludge
disposal. The disposal of the s1urry~ wet sll)tig~~ is subject to, and does
not satisfy the promoition on the land disposal of liquids as ARM. Also, the
potential for airborne transport of metals may not be completely addressed.
(See the water plant treatment discussion.) The no-added action does not
attain the ARARs requiring continued collectiun of leachate and continued
run-on and run-off controL This alternative also assumes the Town of
Minturn will withdraw ground water from the current wells at ,current rates.
COMPLETE CAPPING fUSE RESTRIcnONS/NEW WATER SUPPLY
This alternative provides: draining the historic pond; completion of low
permeability cap; dewatering of water treatment sludge and disposal in lined
cell at the crP, prohibiting ground water use in the historic waste
m~n::tgement unit zone of influence by zoning, deed restrictions and well
permit prohibitions; and relocation of the Minturn Town well outside of the
historic waste management unit zone of influence. By providing an option for.
long-term management of dewatered water treatment sludges this alternative
would allow the cap to be completed, and would eliminate the land disposal
of liquids. This alternative would not attain the- ARAR reqUiring leachate
40-
-------
m.
IV.
collection or containment. The discl1arge from the water treatment plant is
subject to NPDES permitting and ultimately must meet water quality ARARs
and goals.
. ,
EXTRAcnON FROM EXISTING TRENCHESjTREATMENTj
NEW UPGRADIENT DIVERSION TRENCH
This alternative includes the components outlined in Alternative II, and adds
'two elements. rust" extraction of ground water from the two collection
trenches located at the toe of the CI'P would continue until it can be
demonstrated that surface water quality goals can be attained without such
ground water extraction. The cont~min~ted water would be treated at the
WTP. Secon~ a reconstructed trench would be added to divert up-gradient
clean ground, water 'away from the CIP. 'The trench will convey the
unconrnmin~ted grmmd water to Maloit Park wetland to help maintain the
water leveL An additional deep monitoring well south of Cross Creek would
be added to determine the effect of cont~min:1nt reduction in the deep
aquifer. This 3ltemative would not "attain' the RCRA ARAR requiring
,effective leachate conection or containment due to the inadeqUate size of the
,~~ng tten~hes. The discliarge from. the water treatme~ plant is subject to
NPDES permj~ and 111rim:1tely must meet water quality ARARs and goals.
Management of the water treatment plant sludges is discussed as part of the
description of the water treatment plant.
SLURRY WAU./EXIRAcrjTREAT
This alternative includes the components outlined in Alternative n and
, ,
encircling the consolidated' tailin~ pile with a slUrry w~ from the ground
extending from the surface to bedrock. The completed slUrry wall would
divert most ground water from entering under the tailings pile, and also
minimi-r.e water under the tailings pile from moving downgradient. Ground
water extraction from within the bounds of the slUrry wall would be required
with this alternative. This alternative would satisfy the RCRA capping
requirements and mandate for leachate collection or containment. The
discharge from the water treatment plant is subject to NPDESpennitting and
ultimately must meet water quality ARARs and goals. Management of the
water treatment plant sludges is discussed as part of the description of the
water treatment plant.
Table Vll-H illustrates each r~med.ial action alternative for this source area.
-41-
-------
Tobie TI[-H
Alternatlvo I Collection o' Restrict . Currcntl, In pr0r...1
Cap r.lthdr~r.~1 . £0.17. m&&mfi cd
No added action Groundwater rom n urn Well . Capl ~ Olt. 0
and T r.alment . Annual OUI 0
. l)dck1rc cap .nllr. aroo. .~copt th. . 'M~d~..t af graundwa\1t . Pruent Worth. '0
hl.lar e: pond . U.. of ..IIUng can r . a currenl ro .1 . Doea nol aUem kCRA
. Onl~ when complot. wauld a. "round.ollt cDlloc:tlon AllAR ra1l:1I"0\ canlUvnent
mu 11-10;.10.. .lIulnoabllll, cap r'Cche. :r~ p~m,,1n1 to or cdlec?; conlamhalld
ollaln R RA AA R wa cr Ireo en p on leodIoll Qround8Glw
. Llmltod roducllon lit . T'anlp~ ol'mllal. due 11
conlomlnanllranlporl h)'droul hllad fram hl,lor e:
Consolidated pond wll contlnu. '
Tailings Pile . 'MlhOilI cnhancemcnt
.11111111 "anehll wgl not
ollaln cnn A Aft
requlrlnQ of oetlv. laachal.
collection '
Alternallve II Cap Collection o' 3rou~dwaI8f1 ~It~cat. . I~wnenlabl" ~~t orwI
Choracleris\ics: Cop CWo Groundwaler Groundwater .8 estr c lona n urn Well ma arIaI8 awtable 10 tltiGlIII.
.eII.
\lse restrlcllons . 1)J1d!1~ cap' .nt!'. ariS' and Treatment . w.. plfmllling ~.quhd . Relocal. oul.ld. Zonl . Cupit.. eoal. '5~
Tho ClP coverl about 69 acrca Relocale Minium well . AMu" 011.1. 2 '
Induit II hlalarle: pon . U.. of o~lallng of lIt8uencl 01 hlllar\c . P~ llcot Worth. 11101.000
Appro.lmolel~ 40" ollho pilo . Llulll-larlh1auarmoabUIt, cap "round.aler coU.cllon . OD,d rOltrlcllonl wa8l. managem.nl baaed an I~~ar II. 9
hOI been copped otlalnl A AR ,.cchtl oed p~m"lny 10 unit dlscounl ral
. Conlamlnant .0 If rea ",on P on . Zoning . DOel nal alia HCRA
Conlrlbutes 10 40" 0110101 tronaparl .111 b. reduc.d . 'ranaporl 01 m.lal. due 10 ARAR raTkIl~ conlaWn8nt
molol. loading 10 Iho [agio River h)draullc hlad from hl.lorle: fII edlcc?; 0 contamlnaled
pond wUl be ellmlnol.d loochat. groundwolw ,
Db jectives/Gools: . 'Mthout Inhancement
..I.IIn~ t"nehu wll not
olloln CRA ARAR
Reduce r~ulrlnCJ .1I.e:tlvl I.achal.
groundwoler Ironsport C Ie lion
01 meloll
Conlrol or .Iimlnol. Ingoltlon Alternative III Cap Collection and Groundwator Uonltorlng . Imr.wnlOlobI. 01 l.tractlon
Alternate II plus treatment o' Diversion . Irs wn CIId III. WIP are alrlCld}
01 Yhoundwoler coni amino led Iri :tIlI'otlon
b~ II CTP Collection 01 up gradient . I)Jlckl~ cap' .nllrl area, Groundwater . Cap tal Coat. ,141.000
groundwater . Conve~ clean woter around . Dcap .clln UoIoIl Portl . Annu" 0"'" S 000
Conhol or elimlnale '..pO lure Indud II hilloric pond . Use 0' exlsllng . P~ucot worlh. 1618.000
to minD loilngs and olrborne . LlultHa}«r R laUfFm.obllll, cap ~roundwalar calloe:llon ' CTP In 0 wellandl . Rogular lampllng based an 10 ~ar III. 51
conlomlnonla . altaln. CAR rec'h~1 Qr,d p~m~'ny 10 dllCounl ral. '
. Conlomlnont .0 er reo men p an . COil far wolar 'r.olment
Tho flool Remediation fall IIonlporl will bo reduced . New dlver,lon Irp'c:h Includad 01 Tabl. VII-J
lor Iho [0210 Rivor oro ased abov. 101 01 Cl
u~on tho olorodo lVSs as . Mlhoul anha~emonl
A ARs ' .xlllln~ Irln II wlil nol
olloln ClIA ARM
ro~ultlng ollecllva loochol.
co ecllon
Alternative IV Cap 80nloln CTP funiclng!. . [xlremel, dlillculilo ~sml/l
roundwater rea men' . A pr.-con.welton r Ichnk.
Containment 01 CW In"u~ollon re~h
groundwater . I).Jlckl~ Call entire orca, . Perlmeler Ilurry woll . Reduced IIow (10 gpm) duo to . Capll Cost. II .815.000
Indud II tiblorlc pond Ilurr~ woll . Annual 0""', 5 660
. t.flllll-Io)«r, low fcrmeobllll~ cop . ll~d 10 bedrock . Ptcot Worth, 112.918.107
allolns CRA}J AR . Would contol~ conlomlnolod . Exlractlon wells Insldo based an 10 rar /II. 5.
. Conlomlnonl groundwaler eachotl conlalnmenl dilcounl rat. .
Iron'porl will be reduced and 0110111 RenA ARm . COil far wa er treolment
Included at Tobl. mI-J
-------
~
The remedial action objectives specific to this source of coDt~m;n3-tion is to: prevent direct
contact exposures to t!1li1ings or cont1Jminated sediments ill the Maloit Park Wetlands and
to re-establish vegetation to a more natural self-sustaining condition. Two alternatives were
defined:
L
n.
NO ADDED ACl10NfREMOVE VISmLY CONTAMINATED SOll.S
This alternative includes removing only the visibly cont~m;nated soil from an
area of approximately 7 acres to a depth of 12 inches and disposing of. the
material in the crP. Revegetation would occur in the substrate. This
alternative could allow the oxidation of residual. metals and the release of
those metals by ~ water iIifiltratioD. for 'tranSport to the Eagle River.
REMOVE VISmLY CONTAMINATED SOll.SfREPlACE wrrn
IMPORTED FILL AND TOPSO~/REVEGETATE
This alternative includes excavating the surface soil to a depth of 12 inches
from the appr~m~tely 7 acres and to a .depth of 24 in~es from an area of
approximately 2.6 acres within that 7 acres. The contamin~ted material would
be disposed of in the CIP. Fill would be imported and placed within six
inches of final grade. Fill would be placed almost immediately after removal
to prevent oxidation and release of residual metals in soils. Then six inches
of top soil would be placed over the. entire area. Finally, wetlands type
. .
vegetation would be planted over the entire area. 'J:1ili alternative would
mitigate wetlands impacts.
Table VII-I illustrates each. alternative for this source area.
-43-
-------
IMalol' Park Wetlanda I
Charae I eris lies:
The Malall Part< Weiland,
cover, approximately 27 acres
and received tailing. outwash
lor a number 01 year.
The talllng:l and contaminated
soR range In deplh Irom 1 to
2 leet and cover an area al
approximately 7 acres
Estimated total of 15,800
cubtc ~rd, 01 tailings and
contaminated sediments In
the weiland
Ob jeetlve/Goals:
Prevent potenllallngesllan/
Inhalation e.xposure
Re-establish vegetation to 0
natural condillon
Table 1?II - I
Alternative I " Ol~os~ In ' Revegetation
7 to 5011 a ed /
Removal 0t IIIslbly or lead alllng$ pile
conlamlna e~ materials . Yay be hlnder.d by low
and revegeta Ion . . See figure VI t -H pH or metal.
.
. low Impact earthmoving
. 12 tnch r.moval of 7 ocr..
. 11,600 cubic yard I to be
removed
. T08lngs exempt Irom RcRA
Subtitle C 01 BeiliU Wast.
Wetland. vegetation
. '0 year. '0 ensure ,.vegetotloo
Alternative II " Olspo~al In " Import fill and
7 yonlo Ida ed -I Revagetate
Removal 01 visibly QUlngs pile
contaminated materials and . Rapidly Imported fill
Immediate filling and
revegetation . S.e flgur. VII-H . Will prevent oxidation
at eve etotlo
. low Impact earthmoving
. 12 Inchel from 7.2 acrel
. Addilional12 Inches Irom 2.6 acres .
. 15,800 yards to be removed
. Tolllngi eKem~t from RCRA
Sublille C 01 Bevill Wa,te
and prom' r g
'. Wetland. vegetation
. . Rapid revegetation ,1m.
n
. EconomlC8
. Capital COI'. "55.000
. Annual 0"" '1 000
. Plesen' worbi. 1112,000
(baaed on '0 xeal' I Ie 51
. dllcount rot.)
. . Capital Co.t. ,432.000
. Annual OUA 11.000
. Pluent Wor\h. 1450.000
. (baled on J )'Itor 11'.51
discount ro'.)
-------
.Water Treatm.ent ~
The following section analyses the most promising alternatives for continued treatment of
con~m;n~ted water at the WI'P and m~nagement of WI'P sludges. The objective of the
water treatment plant operations is to: provide adequate capacity and treatment
perfOl"Dl8Dce 1IDtil such time that water treatment is DO longer required to consistently
achieve the Fmal RemediatiOD Goals ill ~ Eagle River.
L
n.
NO ADDED ACI'IONjTREATMENT UNTIL WA'IER QUAlITY
GOALS ARE MET/SLUDGE DISPOSAL IN CI'P HISTORIC POND
This alternative consists of continuing the current water treatment operations
until the Eagle Riv~r water quality criteria. are met. Under the current
scenario, sludge will cOntinue to be pumped into the historic pond at the crP.
The disposal of wet sludges do not satisfy the RCRA prohibition on the land
disposal of liquids. This alternative does not allow completion of the cap.
CONTINUED WATER TREATMENT UNTIL WATER QUAlITY
GOALS ARE MET/DEWATER AND DISPOSE OF_SLUDGE AT CIP
This alternative includes dewatering of the sludge and its placement in an on-
. .
site cell The dewatering process would decrease the sludge volume
substantially. The sludge would be placed on the crP in a lined cell. At
closUre, the lined cell would be capped. This alternative also provides for
construction of a ~tem to convey any incident storm water collected in the
cell to the WTP. The discharge from the w~ter treatment plant is subject to
. NPDES permitting. and ultimately must meet water quality ARARs and goals.
If the water trea~ent sludg~ are disposed on top of the CTP, the historic
p.ond must be eHminated and infiltration control must be implemented that
is equivalent to the level of control that would be provided by a completed
RAP cap. Similarly, if additional water storage is required after the historic
pond is eliIIrinated, a lined pond may be constructed on top of the CTP only
if the crP cap is complete or some equivalent method of infiltration control
has been implemented.
-45-
-------
In.
IV.
v.
CONTINUE WATER TREATMENT UNIU. WATER QUA!lTY GOALS
ARE MET/DEWATER SLUDGEjDISPOSE OF SLUDGE OFFSITE AT
AN EXISTING FACILITY . .
'Ibis alternative is the same as Alternative n, but substitutes the disposal' of
dewatered sludge at an approved off-site disposal location. The nearest
faciIityof this type is near Bennett, COlorado, in the eastern part of the state~
The facility is subject to RCRA Subtitle D and must hold a county
Certification of Desig1'~tion. . .
CONTINUE WATER TREATMENT UNIU. WATER QUAIITY
GOALS ARE MET/DEWATER SLUDGE/DISPOSE OF SLUDGE IN
CONSTRUl:u:.JJ DISPOSAL CBT J IN EAGLE COUNTY
This alternative is ~e ~ ~ Alternative ~ but includes the construction
of a sludge disposal facility in Eagle County. The proposed facility would be
subject to State pet.a1iltiJ1g requirements and receipt of an Eagle County
Certificate of Designation.
CONSTRUcr ARTIFICIAL WETLAND FOR WATER TREATMENT/
DISPOSE OF CONTAMINA'IED SUBSTRATE IN -crP
, .
This altemative iJ1clunes the CODStnlCtion of an artificial wetland to treat all
collected water, preparation of a disposal cell in the CTP for contaminMed
substrate, and the disposal of the cotttaminated ~lr4te in the crP. The
wetlands would remain in operation as a treatment facility until such time as
water quality in the Eagle River has met the specified criteria.
Table VU-] illustrates each alternative for this source area.
-46-
-------
Water
Treatment
Characlerlsllcs:
Innuent Include. [aQlI
IAlnl seepage, and C1P
leachalo/graundwalcr
Seasonal ma.lmum Ihroughput
based upon £a9le Rlyer low-Rolli
Db jeclive/Gools:
P/ovldl adequolo copocll ~
and Ireolment perlormonto
unlU wolar Iroatmonl
I. no longer requited 10
ochei"e nnol Rcmedulloo
Cools In lh~ [ogle River
Allematlve I
No added ocUon
. Consls" 0' conllnulng thl
currcnl watcr t/Calment
opera lion. unlllhi £ogl.
River watu qualll~ cr\lorla
arl mol
Allemallve II
Conllnuo W1P operallon,
de water sludge, onl to
dl~osol !It or noor
ClP loellil
Allernallva III
Conllnuo WTP
opcrallon, dewaler
sl4dgo, dlsposo 01
exlsllnlj oflslle (ocllll)'
Alternallve IV
Conllnuo WTP
opera lion, dewaler
silidge, disposil 01
loeor lo-be-cunslrucled
'otilil y
Alternative IV
Treallnenl In
orlillclol wel nnd,
di5poso subslrulo
in r. TP
--------------
Trealmenl
. Alkallnl proclpllatlon/
clarlRcallon
. NPOES Permll flqulrod
. E'.ucnt lallsn.. BAT
Trealment
. Alkalln. proclpltallonl
clarlnca\lan .
. NPOES Pcrmlt foquhd
. EIRucnl .aU.n" BAT
. [Inuent Irlal.d to
permn Ilmlla
Trealment
. Alkaline proclpllallon/
clarlntallon
. NPDES Pormllllqulr,d
[IRuont 1011.0" BAT
. Elnulnl tr~aled to
pormllllmlil
Trea'mdn'
. Alkallnl pllclpl\allonl
clarlncallon
. NPOI::S Pormlt roqulrod
. [IRuonl .01111181 BA'
. E!Ruont Irflaled to
permlilimlls
Table :2II-J
Wet Sludge
Disposal at CTP
. 150 cubic 'fOIdl/do,/ (Wit)
. . 4-101.olldl
. 00.. nal cam!!l,! "lIh
p'rohlblllon on lalld
iilspolol O. liquid.
Sludge
DewcJler'ng
. fVtrollon O( aludg.
. Comllllu 111 th
r.rohlbltlon on
and .dl,polol 0'
liquid'
Sludge
Dewdterlng
. f1trollon 0' lIudgl
i Sludge
Dewatering
. flItrollon 01 .Iudgl
~
Treolment
. ~~ ~Is~w SUbS':j
Oetolls unavuloblo
Detail. unavailublo
. Impllmentobl.. CUlf8ll1l,/
~ opuallon .
. Don not allow camplltlon
01 the ClP cop
&.Ialntolnl h)dioullc hlad
anC1P
. Capital Co.t. '0
. Annual OW I 000 000
. P/8ICnt Worth; ~7.1~2.000
. (Oaud on 10 )fIOf 11'0.
51 dl.count ,otl)
Dlap-0lal In c.U
at CTP
. 50 - 10 cubic vardl/do,/
. 20 ~o, copaclty
. Llnld c.1 wllh Iquhdant
~l1Ilfallon p'rol8Ctloft
10 cap proVidod ~ RAP
OIl.U. Dlspo1a'
at Existing Facllltv
. Sludgl not ACRA hOlardou..
II dellolor.d mllY bl
dbl'"sed In ACAA Subllll. 0
rotUlt~
0":51', dlSJosal
loco o-b
conslructe . Facllltv
. Subloct 10 fagl. Coun'v
CII OIlco\lon 01 Dealgnatlon
. Sub Joct to .Iole
pOllnll ..qultomentl
. Cell 10 bl trlpll Ilnld.
Iwa .~Ihillc, ani clo,/
. Implom.nlobll. CUI"nll,! In
Gpllallon. aludgl dOllolOllng
and dlspo.aI requlr. addlUoIIaI
.qufclmont
. ADaw. camplillon 0' the C1P c~
. fllmlnat.. "'100110 "lad on C1P
I Capital Call. 3,592,000 .
. Annual OW I 552 SOO
. Plount Yt'OI'h. ~15.~BO.0]0
(bosod an 10 )Car Ille
51 dllCount ,ato)
. Implcmcntabl.. curr.nll,! In
operotlon..ludge d8wotOlIn,
GIld disposal .equlrl oddltlonal
.qulpm.nt
. Lang dilianc. "anlpOlt fl~""
. AUo..1 campletlon oJ th. CTP cc!p
. £llmlnat.. "1auliC "Iod on C1P
. Capital Casl. 62!!,000
. Annual Old.l, 2 "bS 000
. Pllunt Walth, 121.145.000 .
(baud on 10 )'Iar IIf.
51 dl.coun' .01.)
. Implomlntobll, W1P cU(flnU~
~ op.erotlan. .Iudgo dc.olermg
requires odailional .qulpmcot
. Lond acqulllllon and p8lmlll~g
mo,/ b. problimollc
. Allow. complillon 01 Ihl C1P cop
. Capllol Cost. 1].801,000
. Annual OW I 608 000
. P/esDnt WOlih. 'I6,~I4,OOO
(basad on 10 )'tot 1111
51 dlscounl roto) .
. Innavalivi and unprovlR.
. Labor. materials and
equlpmenl ulslln 0'00
10 Inslall wellands
. Capllal Ca,I, ,S791.000
. Annual 0&1.1 117 ,DOO
. PIClent Wal'h, 11,940,000
(based on to )CQ( III..
5" di5counl rulo)
-------
vm. COMPARATIVE ANALYSIS OF ALTERNATIVES
A.
Ea~e Mine Seena~
OveraUJ»rotection of Uuman Health and the En~ronment
This criterion assesses the protection provided by each alternative to human health
and ,the environment. Overall protection focuses on the level of protection provided
by each alternative, and how Site risks will be e1iminated, reduced or controlled
through treatment, engineering or institutional controls.
Alternative IV is most protective of human health and the environment. Alternative
IV consists of a toe drain along the south side of Rock Creek to intercept surface
and subsurface seepage and a ~ io convey the collected,seepage'by pipeline to
the WI'P. The alternative includes the construction of a culvert system to divert
Rock Creek surlace flow from a collection point above the elevation of the mine
pool to an existin~ culvert which drains into the Eagle River. This will isolate clean
surface water from contaminaJ'1ts in the conuvium in the lower part of Rock Creek
and will m;n;m;7.e the amount of water collected in the toe dtain.
The principal environm.euta1 impact frOm this source is contaminated seepage
entering the Eagle River at concentrations ,toxic to aquatic ,life. Alternative IV
controls those impacts to the Eagle River by effectively reducing the amount of
contaminated seepage that is released to the river. Treatment of the cont:1min:ned
water collected in the trenches will occur at the WI'P.
Alternative m provides equivalent protectiveness to Alternative IV but will require
treatment of a larger volume of diluted, cont~m;nated water.
Alternative II is less protective than Alternative ill or IV because, as proposed: the
exttaction wells are less efficient at collecting the colluvial water than an interceptor
trench; the current surface seep collection ditches are exposed and subject to
continual degradation from rock slides and storm events; and the current ditches do
not extend far enough upgradient to collect all the surface seeps. It is possible to
enhance Alternative II to achieve protectiveness comparable to Alternative IV. The
enhancements required for comparable protectiveness would include:, additional
extraction wells combined with containment of the colluvial water to ensure effective
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collection of subsurface seepage from the colluvium; collection of additional
upgradient seeps or demonstration that lowering of the mine water level e1imin~tes
the upgradient seeps; and enclosing the system which collects the surface seeps.
Alternative I - No added action, is not considered adequately protective of the
environment. Water quality data for the Site indicates that this area, despite the
existing seepage collection, rem~in!l: a major source of "cont~min~nt release to the
Eagle River. ..
There are no unacceptable short-term or cross-media impacts associated with any of
the Alternatives except Alternative L Both the toe drain and extraction well fielci
can be constructed without causing added release of metal cont:tmin:tnts to the Eagle
River.
ARARs
None of the alternatives will serve to attain surface water quality ARARs and goals
independently. It is only through combined actions at all"of the source ~eas that the
final remedia.rion goals will be achieved Alternatives IV _and Alternative II, if
. ~nh~nced, would be equivalent in their contnbution towards ARARs attainment.
Alternative I and II (as proposed) and ill do not extract and thus prevent as large
a mass of cont.a.min~tion from re~t"hingthe Eagle River as Alternative IV.
Lon~ Tenn Effectiveness and Pennanence
None of the alternatives would provide a permanent solutio~ however Alternative
IV will be effective until such time as the seepage from the mine has improved ~
quality so that treatment is no longer required. Alternative IV is longer term and
requires less maintenance than Alternative 1, is more effective and as permanent as
Alternative II. and is more effective and as. permanent as Alternative ill.
Reduction of Toxicity. Mobilitv or Volume
Alternative IV reduces the vol~e and mobility of the contaminants to a greater
degree than Alternative ill, II and I. The clean water diversion provided in
Alternative IV will prevent cross contamination of clean surface water and minimize
the volume of water requiring treatment.
49-
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Short-Term Effectiveness
Alternative IV provides short term effectiveness that is equal to or greater than the
other alternatives.
ImnlementabiUtv
Alternative IV is somewhat more difficult to implement than Alternatives I and n
due to the difficulty of excavation. However, the toe drain is believed to be more
effective in collecting the seep water than the existing collection system and/or the
, proposed extraction wells. The implementability of Alternative IV is similar to that
of Alternative n and will reduce the volume of water requiring treatment.
~
Present value cost for Alternative IV is S263,000, compared to $192,000 for
Alternative IlL $107,000 for Alternative n, and $125,000 for Alternative 1.
B.
Waste Rock Piles/Belden Non-Point Sources
, Overall Protection or Human Health and the Environment
Because the cont~m;n~nt release from potential sources in the Belden area is not
adequately characterized, it is difficult to evaluate the relative protectiveness of
rll'mll'diaI alt~1"T1arives. Theoretically, Alternative IV, total removal, should provide
the greatest protectiveness. Removal of all waste rock could reduce this soura: of
metal conr.:tmina.tion thereby reducmg the risk to aquatic receptors in the Eagle
River. After Alternative IV, Alternative ill would provide the most protection by
removing a substantial p()rtion of the source of metal cODtamin3-tion. Alternative n
does not provide protection of the e~onment because it does not include activities
whic;:h will reduce tranSport of metals into the Eagle River; it does however, provide
the basis for assessing future, actions. Alternative 1, No Added Actio~ does not
provide adequate protection of the environment.
It is probable that unacceptable short term impacts would be associated with
Alternatives III and IV. It may not be possible to prevent an increase in transport
of metals to the river during removal due to the steep, unstable configuration of the
piles and the very limited work area available along the river. Exposed surfaces left
after removal could produce a dramatic increase in excess metals due to infiltration
of snowmelt or by surface flow during stonn eventS.. It is possible that transport of
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metals by storm events could be a long-term result of large removal actions at this
location. .
ARARs
Without additional data, the applicability or relevance and appropriateness of the
stormwater regulations are not certain. The proposed monitoring will allow that
potential ARAR to be fully developed. If it is determined that the stormwater
i'egulations apply, EP A would evaluate whether an Explanation of Significant
Differences (ESD) would be necessary. .
I.dmI:J'erm EfI'ectiveness and Performance
Currently, there is no reliable evidence that any of the alternatives would be effective
for long-term reduction of metals loading to the Eagle River~ . Total removal could
provide some reduction in long-term loading, but the magnitude of that reduction is
unknown.
RedUctiOD olToxicitv. Mobilitv. 01' Volume .
Alternative.n will not provide a reduction in'toxicity, mobility or volume of .the
CODtamin:lnts. Alternatives m and IV may reduce mobility below the current levels.
The extent of reduction by any of the alternatives cannot be estimated.
Short-Term EfI'ediveness
Alternative n provides greater shon-term effective~ess than Alternatives ill and IV
and. is equivalent to Alternative L Alternatives' ill and IV are unlikely to be effective
in the shon term due t~ shon-term d~gradation of surface water quality in the Eagle
River. Significant degr;idation will result from the disturbance of the waste rock
required for removal. A long period of time may be required for the river to recover
from that impact.
Implementability
Alternative n is much easier to implement than Alternatives ill and IV and slightly
more difficult than Alternative 1. Alternative ill would be difficult to implement and
Alternative IV would be the most difficult given the location and amount of
earthwork that must be performed.. Depending upon the configuration of the naturai
ground surface underlying the waste rock it may not be possible to totally remove all
of the waste rock.
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.~
Present value cost for Alternative II is $186,000 compared to no added cost for
Alt~rnative ~ $9.4 million for Alternative ill and $28.3 million for Alternative IV.
c.
Roaster Piles
OteraJ1..l"'~OD or }Inman UmlJ,th an~DviroDment
Alternative IV is the moSt protective alternative developed for this source area.
Expedited revegetation combined with collection and tteatment provides the greatest
. .
reduction in metals tranSpOrt. Alternative m provides application of lime and
covering the area with topsoil. Topsoil will expedite revegetatio~ reduce infiltration
and reduce acid formation by m;n;m;.,.;ng the oxygen level in metals laden sediments.
Alternative II provides some protectiveness by preventing cont~m;nated surface water
from the Roaster Pile arca from'cntering the Eagle River. Alternative ill is more
'protective than Alternative I but less protective than Alternative II. Alternative I,
No Added Action, may not be protective of the environment.
ARARs
Alternatives m and IV will both contribute to attaining ARARs by controlling
stQI1I1Water. Alternative . m will accomplish tl$ by preventing cont~ with.
cont~n";n~ted materials. AlternativelY also accomplishes this and provides added
. progress towards achieving the surface water quality goals by collecting the seepage.
Lon~ ~ff'ectiveness and Pennaneuce
Alternative m will have long term effectiveness by reducing contaminant tranSport
on a .permanent basis.' Aiternative IV includes the activities of Alternative ill so it
would be equally effective. The added water collection and treatment component
of Alternative IV does not increase the long term effectiveness or permanence.
Alternatives I and II may not be effective in the long-term and may not lead to a
permanent reduction in metals loading to the Eagle River.
Reduction of Toxicitv. Mobilitv or Volume
Alternative ill will be more effective in reducing the J?obility of the contaminants
than alternatives I and II. Implementation of alternatives II or IV would result in
a greater reduction of volume and toxicity of the contaminants delivered to the Eagle
River.
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Short. Term Effectiveness
Alternative n and IV would be the most effective in the short term because
collection of the discl1arge can be quickly. linked to the existing pipeline in Belden.
Alternative IV will also be more effective in the short-term than the No Added
action.
IDmJemeDtabill~
Alternative m will be very difficult to implement given 1) access to the area with a
Deed to transport topsoil via railroad, 2) the extreme slope of the drainage and 3) the
boulders located in the drainage. Alternative I is implementable as it requires no
remedial activiti~ Alternative n is implementable and Alternative IV would be
comparable to Alternative m to implement.
~
Present value cost for Alternative ill is $239,000. This is compared to $66,900 for
Alternative I, $63,000 for Alternative n and S272,OOO for Alternative IV.
D. .
Rex Flats/Old Tailin~ Pile Areas
OveraIl..P""t~on or f'nmSlln Health and the En~i~nnte4t
p.]t,:~~rive n will provide better overall protection of human health and the
~onment than Alternative I by requiring an altc;auate water supply if future
development of the areas occur. Proh1oiting ground water withdrawals will provide
protection of human health until such time that the natUral attenuation o'~ metals in.
the groundwater occurs.
ARARS
Attainment of ARARs in the Rex Flats groundwater is based upon meeting the
surface water quality ARARs in the Eagle River. None of the alternatives will serve
to attain surface water quality ARARs and goals independently. It is only through
combined actions at all of the source areas that the remediation goals will be
. .
achieved. Due to the . interconnection betWeen the Eagle River and the Rex Flats
groundwater, improvements in Eagle River surface water quality will promote
attainment of the contaminant specific groundwater ARARs at Rex Flats. At the
OTP, the groundwater is of limited use and quality. As a Oass V groundwater area,
ARARs for the OTP were not identified.
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Lone- 'tam.Eff'ectiveness and Pennanence
The long-term effectiveness of both alternatives is dependent upon the success of
loc:al government at limiting the use of the ground water in the area. However,
Alternative n provideS some increased effectiveness by anticipating the demand for
water tbrough provision of an alternate water supply to the Site.
RedumoD of 'fpucit't'. Mgbj1i~ or Volume
Neither alternative will reduce the toxicity, mobility or volume of the CODt~m;n~nts.
The alternate water supply element of Alternative IT does further ensure that the
restrictions on ground. water development will be effective.
Short-Term Erreetiveness
Alternative n will be somewhat less effective in the short term than Alternative L as
it requires the installation of a pipeline and appurtenances.
Imnlementabilitv
The Alternative n will be slightly more difficult to implement than Alternative 1.
QWI
Present value
Alternative L
cost for Alternative n is $284,000 coUlpared to $15,400 for
Eo
Consolidated Tai1m2S Pile
Overall Protectiveness of Human Health and the Environment
Alternatives m and IV are equivalent in protecting human health and the
environment. Under Alternative m, human health will be protected by moving the
. Minturn municipal water wells. The environment will be protected by: completion
of the cap; sludge dewatering; continued pumping of the extraction trenches to
reduce contaminant tranSport to the Eagle River, and the installation of up gradient
diversion trenches to reduce tranSport of metals by groundwater. Alternative IV
places a slurry wall around the crP and pumps groundwater from the interior to
create a barrier to further reduce transport of metals by groundwater. With
Alternative IV it will be difficult to guarantee placement of a gap-free slurry wall due
to variable subsurface conditions. Less protection of the environment is provided by
Alternative n beca~e continued extraction of contaminated ground water from the
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trenches is not included. Alternative I is the ,least protective. Continued disposal of
wet sludge at the pond will maintain the hydraulic gradient that is leaching metals
from the CTP and transporting them to groundwater. Alternative I will not pro~de
protection to human health or the environment.
ARARs
The Colorado Standards for Owners and Operators of Hazardous Waste Treatment,
Storage and Disposal Facilities, (6CCR 1007-3 Part 264, Subpart N) Landfill
standards were determined to be relevant and appropriate to the crP because the
tai1in!rJ materials are sufficiently similar to hazardous wastes to warrant imposition.
The Subpart N, Landfill s~dards. ~~quire construction of an impermeable cap and
continued leachate conf:ainment or ~lleCtion. Only: Alternative IV satisfies both of
these requirements. Alternative ill will only satisfy the leachate collection
requirement if the trenches are enhanced to 1.ulf>rove their perfonnance.
Loml- Term Effectiveness and hXlllanence
Alternative ill would provide greater long-term effectiveness and permanence than
Alternatives I and n and would be approximately equivalent- to Alternative IV in
these aspects.
RetiudieB.&( Toxicity. MobiIitv or VoJD~e
Alternative m will be equivalent to Alternative IV, in reducing the mobility (by
extraction) and toxicity (by treatment) of the groundwater. . Alternative, II would
provide only limited amount of mobility and volwne reduction. Alternative I would
not sufficiently reduce mobility and volume.
m .ven
Alternative m provides short-term effectiveness that is greater than Alternative IV,
II and L By immediately collecting leachate, eliminating the historic pond and
diverting up gradient groundwater, Alternative ill would reduce metals loading to the
Eagle River to a larger degree and more quickly than the other alternatives.
Imnlementability ,
Alternative ill would be more easily implemented than Alternative IV, approximately
equivalent to implementing Alternative II, and slightly more difficult to implement
than Alternative L
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~
Present value cost for Alternative II are $606,000 compared to $679,000 for
Alternative m and $1292 million for Alternative IV. Costs for Alternative I have
not been estimated, but should. be considerably less than those of the other
alternatives.
F.
~
OveraU...Pmtedion or -e:uman tkII1h and the Environment
Alternative II provides overall protection to human health and the environment by
removmg the contam;~a,ted so~ disposing the cont~m;na,ted soil at the crP and
replacing the removed soil with uncontamina.ted material. Under Alternative I the
environment may not be protected as metals in sediments below the surface may be
oxidized and released to groundwater and surface water. Similarly, Alternative I is
not protective of human health as the potential for direct contact exposure to
cont~m;nated tailing and sediments remain~
ARARs
Both altemattves provide for disposal of the tailings in the crP. Either Alternative
m or IV presented for the Consolidated i'ailings Pile will attain RCRA ARARs and
contribute to attainment of ARARs and goals in the E3gie River.
Lon~- ~ffediveness and Pennanence
Alternative II will provide for greater long term effectiveness and permanence than
Alternative I due to a greater probability of providing effective vegetation. If
significant t~ilinS" materials are left in the wetland at the completion of Alternative
1, metals transport into the Eagle River by surface runoff and shallow groundwater
and direct contact exposure risks will continue.
Reduction of Toxicity. Mobilitv or Volume
Alternative II would be more effective in the reduction of the mobility of the
contaminants than Alternative I. by more quickly re-establishing a reducing
environment and eliminating direct contact exposure.
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Alternative II wi1l be more effective in the sho~ term than Alternative I by covering
and quickly creating a reducing environment and elimin,,-ting direct contact
exposures.
lmDJementability
Alternative II and Alternative I are equally implementable.
~
Present value
Alternative L
costs for Alternative II are $450,000 compared to $172,000 for
G.
Water Treatment Plant
Overall Protection or Human Health and the Environment.
.Alternative II is protective of human health and the environment. Dewatering of the
sludg~ and onsite disposal in a.properly designed cell wi11 prevent the migration of
metals and allow completion of the cap. Alternative ill is roughly equivalent in
. protectiveness; because sludge will be removed entirely from the Site, there may be
some risk from increased truck traffic in the area. Alternative IV is similar in
prote",'tiveJ1es5 to Alternative m. assnming that a suitable offsjte disposal cell location
. .
can be found in Eagle County. Alternative V may not be as protective as ill and IV
be~11~p- COT1t~min::Lted wetland substrate may contain leachable metals at toxic levels.
Alternative I is not protective; continued disposal of liquid sludge at crP will
continue to cause infiltration and maintain the release of cont~minated groundwater
from crP. .
ARARs
Continued operation of the water treatment plant pursuant to the existing permit will
contribute to attainment of the TVS as ARAR in the Eagle River. CPDES permits
are renewed once every five years. The sludge is not characteristic and is not listed
and therefore, is not hazardous waste. During the renewal process, EP A may
recommend that the permit limits be adjusted to reflect the Colorado TVS, because
these standards are the surface water quality ARARs and Final Remediation goals
at the Site. Alternatives II, ill and IV all attain ARARs. Alternative I does not
attain ARARs as the Colorado Regulations Pertaining to Solid Wast~s Disposal Sites
- . .
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. and Facilities prohibits the disposal of liquids in landfills. The ARARs affecting
treatment in an artificial wetland have not been evaluated.
~D~~~~nWD~sndh~n~~
None of the alternatives can be considered as a permanent solution although each
would be effective if continued until Eagle Mine seepage and C1'P leachate reach
a quality aDd quantity protective of the environment.
RedumoD ot ToxicitY. MWDlitY or Volume
Alternative ~ n, m and IV will reduce the mobility of the cont~m;n~nts by treatment
and disposal. . A undesirable side effect of Alteri1ativ~. I .is the maintenance of the
hydraulic drive which leaches con~m;nants .from the tailings disposed at the CI'P.
If demonstrate~ Alternative V would reduce the mobility by sequestering the
C011f~III;nan:ts in the substrate.
Short- Tenn Efl'ectiveness .
AlternatiVe n is approximately equivalent in short-term effectiveness to Alternatives
. m and IV. Alternative I is not effective.in the short-term as closure of the historic
. .
poJid and e)im;natiOD of the hydraulic drive are not accomplished. Alternative V
would be somewhat more effective than Alternative m or IV in the short term.
1mDJ.~eDtabi1ity
Alternative IT will be easier to implement than Alternatives ill and IV, approximately
as implementable as Alternative V, and slightly more difficult to implement than
Alternative L .
~
Present value costs for Alternative n are $15.58 millio~ compared to $7.72 million
for Alternative 4 $21.75 million for Alternative m, $1621 million for alternative IV
and a very speculative estimate of $1.94 million for Alternative V.
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IX.
SELECI'ED REMEDY
The selected remedy for cleanup of the Eagle Mine Site is comprised of one alternative for
each of the seven areas of the Site that EP A has found are contributing metals loading to
the Eagle River or have been evaluated for public health concerns. The following are the
selected remedies for each area determined by EP A to meet selection criteria.
The environmental impact from this area results from surface and subsurface cont~1TIin~ted
mine seepage entering the Eagle River. The cont~min~ted mine seepage is toxic to aquatic
life. The selected remedy for this source area, Alternative IV, controls impacts to the Eagle
River by minimi7ing the amount of cont~minsted seepage which is allowed to reach the
river. In addition to continued flooding of the mine workings, Alternative IV employs a toe
drain as the process option to intercept surface and subsurface seepage and dewater the
drainage. Monitoring of the seep volume and quality will continue and data will be
collected. to verify that the toe drain is effectively colleeting subsurface seepage. The
cont~~ina,ted water collected by the system will be conveyed by pipeline to the WTP for
'. treatment.
The selected remedy includes an inlet and culvert system to divert uncontaminated Rock
. Creek surface flow from upstream of the impacted area, around the collection system, to an
existing culvert which drains into the Eagle River. Diverting the uncontaminated Rock
Creek flows will red~ce transport of contaminants to the Eagle River.
Treatment of the cont~minated water, followed by sludge dewatering and disposal in a lined
cell at the crP will reduce the mobility of the contamination and prevent release of the
metalscont~min~tion to the environment.
The present value of the selected alternative is $263,300, with a capital cost ~f $127,950, and
. an annual O&M cost of $ 17,530. .
EP A has determined that an enhanced version of Alternative II, may provide comparable
performance and equivalent protectiveness to the toe drain. Instead of a toe drain, this
alternative utilizes a well field for extraction of subsurface seepage. The well field would
operate in conjunction with subsurface containment, diversion of uncontaminated Rock
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Creek surface water and. if effective, mine drawdown to reduce seepage. This enhanced
version of Alternative n would require a 90% reduction of the. colluvial flow along Rock
Creek and would be implemented in tWo phases: Phase I would consist of installation of
a limited number of extraction wells and conducting a mine drawdown test lasting one full
year. (Phase I actions are currently underway, wells were installed in the summer of 1992
and the mine drawdown was started in September, 1992, pursuant to an agreement betWeen
CDH and Paramount.) If these actions do not result in a 90% reduction in colluvial flow,
then Phase IT WoUld be executed. In Phase IT, more extraction wells would be added in
conjunction with a subsurface cutoff wall containment strUctUre to retain subsurface seepage
for extraction and tranSfer to the W1? This cutoff wall would be installed at a geologically
favorable location along Rock Creek where bedrock is near the surface and fonns a "slot"
in the canyon. A channel w3s blasted in the bedrOck underlying the "slot" to install the
existing culvert which diverts the . lower segment of Rock Creek.. Also in Phase IL if the
mine drawdown bas not improved the quality of the surface water. in Rock Creek, then an
up gradient diversion will be installed to convey uncontaminated surface water to the existing
culvert. All these actions will be completed within 2 construction seasons of the ~gnjng of
this ROD (that is by November, 1994). .
EP A will evalJI~te the eDh~nced extraction well process option as part of Remedial Design.
The present value of the enhanced extraCtion well. process option is $241,100, with a capital
cost of $104,161, and an annual O&M cost of $17,225.
. .
Waste Rock Piles/Belden Non-Point Sources
At the present time, EP A does not believe that removal of the waste rock. piles can be
. justified. There is insufficient data to evaluate how these areas impact the Eagle River and
it is suspected that other non-point sources exist in the vicinity. Removal of the piles would
cause significant, negative short-term ~pacts to Eagle River water quality. Removal of the
waste rock piles would be extremely expensive given the safety concerns associated with
large scale earthmoving in the confines of a narrow, steep canyon.
EP A does believe that a better understanding of the potential impacts from the Waste Rock
Piles is crucial to understanding Segment 5 of the Eagle River and itS potential for
supporting aquatic life. Without additional information on the loading, the transport, and
the seasonal characteristics of the Waste Rock non-point sources, the proposed biological
stUdies cannot accomplish their. objectives.
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For these reasons, EP A has determined that the proper course of action is to delineate the
surface and sub-surface contributions of the waste rock piles to the metals loading in the
Eagle River. As the result, Alternative n was chosen as the selected remedy for the waste
rock pile source areas.
. .
Alternative n consists of inst3.nation of a. series of monitoring wells near the toe of the waste
rock piles at Belden, plus automatic storm sampling stations at appropriate drainage
locations. In addition, leach tests will be performed on' a cross section of the varied mine
waste materials which comprise the waste rock piles to determine metals availability for
tranSport to the Eagle River. 'Ibis alternative will provide valuable data necessary to
determine the amount of con~mination released and the me~tJani~ms by which the
. . ".
. contamination is transported to the Eagle River.' Until. these' mechaniqus are ~derstoo~
it is not possible t~ develop remediation strategies which avoid the negative environmental
impacts associated with the wholesale removal of waste rock from the canyon. Because
residual contamin3.tion will remain in the waste rock piles, the data collected through
implementation of Altemative n will be eva1uate~ as part of the 5-year review.
The sele?ted remedy for this source area does not reduce the transport of metals to the
~e River, but it does provide a basiS for assessing future actiOIIS. -Likewise., the selected
remedy wID not provide a reduction in toxicity, mobility or volume . of contamjnan~c;", The
present value for the selected alternative is $186,000. with a capital cost of S86.,22S and an
annnaJ O&M cost. of $12,920.
Roaster Pile Area
EP A has selected a modified version of Alternative I for this area. It consists of expedited
. revegetation and direct monitoring of seepage from the hillside below Roaster Pile 1 area.
EP A believes that revegetation is the most cost effective and implen:ientable alternative to
control the loading from the roaster area drainage. The appropriateness of this approach
is directly related to the limited (2-3%) metals loading contributed by the Roaster Pile area
to the Eagle River. The revegetation will serve to control erosion of remnant Roaster Pile
materials and to cut the infiltration of rain and snow-melt through these remnant materials.
As a part of this remedy, seepage which emanates from the area of Roaster Pile 1 will be
monitored directly, on at least an annual basis, to determine the extent of loading reduction
which occurs. .
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In contraSt to the Alternative m presented in the Proposed Plan, EP A has determined that
the addition of 12" of topsoil will be difficult or impossible to implement and may not
provide signiticmt1y better reduction of metals tranSport than the approach developed in the
RAP. Liberal application of lime or other soil amendmentS in areas where revegetation is
unsuccessful or marginally successful can be used to further promote rapid revegetation.
EP A does not believe that allowing 9 years to elapse before evaluating the revegetation
effectiveness as provided in the RAP is reasonable. EP A will requir~ as a component of
the selected remedy, continued monitoring and a five year review of the revegetation
program. At that time, if successful revegetation has. not been achieved, additional lime
application, seeding and topsoiling may be required. .
The present value for the selected alternative is $91,200 with a capital. cost of $24,313 and
10 year O&M cost of $66,888.
Rex F1ats/OTP . . .
TheEP A believes that, with one exception, the current approach prescribed by the RAP at
the OTP and Rex Flats, is appropriate and satisfies the evaluation criteria. The .single
exception is the need. to ensure expedited revegetation.and to clearly provide a mechanism
.10 require additional revegetation if successful revegetation is not accomplished within five
years. For that reason, EP A has selected Alternative n. Alternative n also requires for an
alternate water supply if future development of the area occurs. It should be noted that
extensive monitoring will continue to be conducted in these areas.
The present value for the selected alternative is $284,000 with a capital cost of $265,000 and
an annual O&M cost of $2,430. The capital cost of $265,000 mayor may not be incurred
depending upon futUre land use decisions for the area.
Consolj.dated Tailin~ Pile
EPA has selected Alternative m for the CTP. Alternative m consistS of the following
actions. The crP cap must be completed within 2 construction. seasons after the signing of
this ROD and the historic pond must be permanently drained and capped within one
construction season so that the continued infiltration and associated mobilization of metals
is reduced or elim;nated. Effective extraction and treatment of leachate/ground water is
also required to attain MARs, and must be continued until the crP no longer contributes
to violation of the Final Remediation Goals established for the Eagle River. Enhancement
of the existing extraction trenches and the installation of monitoring wells wiH be required
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to ensure the effectiveness of the trenches. These enhancements include extending the
north extrac:tion trench to intercept seepage which is currently entering Maloit Park
Wet1an~ and adding piezometers at both trenches to provide better assessment of the
extraction trenches performance. The enhancement of the trench will also improve the
overall performance of the CI'P as a land disposal unit.
FmaIly, diversion of clean ground water away from the CTP will serve to reduce the volume
of leachate/groundwater requiring treatment and aid the dewatering of the CTP. The
selected alternative, Alternative In, also includes relocation of the Minturn wells (this action
is currently underway per an agreement between the Town of Minturn and Paramount).
RelO<:aring the Minturn wells combined with groundwater use restrictions provides the
highest confidence that human health will be protected and further degradation of
groundwater will be prevented. Overall, the selected alternative is the most protective of
the Eagle River and of public health. It is implementable and more cost effective than a
slurry wall.
The present value for the selected alternative is $679,000 with a capital cost C?f $649,000 and
an annual O&M cost of $5,000.
Water Treatment Plant .
A refinement of Alternative n was chosen for the Water Treatment Plant. Alternative n
employs the existing Water Treatment Plant with the addition of sludge dewatering and
disposal. The existing water treatment plant attains ARARs by meeting the Colorado
Pollutant Discharge System permit limits. When the permit is renewed. the EP A may
recommend that the permit limits require attainment of the Colorado 1VS as ARAR for
Eagle River water quality. The EPA recommendations will be based on information
developed by extended water quality and biological monitoring at the site. EP A will issue
these recommendations at the 5 year review.
Sludge dewatering is required to satisfy the RCRA prohibition on the disposal of liquids in
landfills. The dewatered sludge is not a hazardous waste and will be disposed of in a lined
cell at the completely capped CfP. The. cell liner will serve as a means of controlling and
managing incident stormwater in the cell to prevent infiltration into the CfP. Incident
stormwater will be conveyed from the cell to WTP for treatment. In addition, the sludge
disposal must be accomplished in a manner which prevents the windbome transpon of the
dried sludge. Continued air monitoring will be conducted to verify that windbome ttanspon
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'does not exceed State and Federal air quality standards. This monitoring may be
discontinued if no windbome traDSpOrt occurs due to disposal of sludge. This alternative
is the most cost effective 'and protective. The refinement of Alternative n includes a
reduced estimate of the volume of dewatered sludge, reduced estimated cost for sludge,
stabilization and a modified type of storage cell
The present value for the selected alternative is $13,609,000 with a capital cost of $2,704,875
and an ~nntnal O&M of $1,403,000.
~
Alternative n was chosen as the remedy for the Maloit Park Wetlands. This alternative
provides overall protection to human heal~ and the environment by removing the tailings,
coDtaining them at the CI'P and replacing them with uncontaminated topsoil material.
Furthermore, the selected alternative will provide greater long term effectiveness because
of the higher probability of rapid and successful revegetation. As noted above, EP A has
ddermiDcd that the p.11h~ncement of the north extraction trench is necessary for the
successfn) remediation of the Maloit Park Wetland. Unless the trench is enhanced, Te-
, . '
CODtamination-of the wetlands will continue.
The present value for the selected alternative is $449,600 with a capital cost of $339,300 and
an ammal O&M of $17,000.
,Biolo~~ Monitoriu2 Plan lBMll
Based on comments received fr Jm the public and the PRP and on further internal review
. by EP ~ EP A has determined that it is appropriate to contiilue a rigorous sampling program
to traek progress of the cleanup and to support the work of the Biological Criteria approach
at the Site. The BMP will enSure that universe of data may be integrated into a package
that will aid the understanding of both the long-term potential, and the limits of Segment
5 of the Eagle River to support an aquatic community. The BMP will serve to evaluate the
monitoring specified in the ROD for each source area to ensure that it is adequate to ass~ss
the performance of the source-specific remedies and that the source-specific data may be
effectively integrated to track progress towards compliance of the Final Remediation Goals
in the Eagle River.
EPA's plan for Eagle River biological and chemical monitorii1g will include surface water
quality analyses, surface water flow measurements, sediment ~yses, surface ~ater toxicity
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testing, and assessments of the aquatic community including periphyton, maaoinvertebrates
and fish. Water quality sampling will be conducted at monthly to quarterly. intervals at a
sufficient number of Eagle River and tributary stations to determine water quality trends
due to remedial actions. Storm event-based sampling will also be conducted in the Eagle
River to determine the impact of storms on water quality in the Eagle River. Flow will be
measured concurrent with water quality sampling so that loading due to the various Site
sources and storm events can be determined
F1Sh sh(\l"1nng will be conducted on an annual basis in the spring at the same areas used for
macroinvertebrate and periphyton evaluation. The relative abundance of game fish. game
fish species, size, and age categories will be determined. In addition, non-game indicator
species will be assessed. Water quality sampling will be conducted concurrently with the fish
shocldng. .
The COS%S for the BMP are uncertain due to pending discussions on the number of sampling
stations, specific parameterS to be assessed. and decisions on when ~l1fficient data has been
collected. The maXimum present yalue cost for this a1temative is Sl~mOOO with a capital
cost of S80~OOO and annual sampling and analytical costs of S39O,000. - These costs are based
oil monitoring for a five year period.
InsnectioD anclMaintenanee Plan
In response to many ",-uuunents. received on the Proposed p~ EP A has determined that
it is appropriate to add a comprehensive inspection and maintenance plan which will define
the approach to verification of the long-term integrity of structures and facilities at the Site.
Although operation and maintenance of the remedy implemented for each of the source
areas is noted as .a component of the selected remedy for that ar~ EP A believes that a
comprehensive maintenance plan for the Site will help ensure the protectiveness of these
remedial actions. The comprehensive maintenance plan will clarify the ongoing
maintenance responsibilities for each area and will include contingency planning and
emergency preparedness evaluations.
Schedules and procedures for inspection of waste rock. piles, the Rock Creek collection.
system. bulkheads in the mine adits, the cap on the CfP and extraction trenches at CfP will
be developed. The plan will include criteria for taking corrective actions when potential
problems are noted during inspections. This will include a process for notifying appropriate
authorities at local municipalities, the county, the State, and EP A of "noted .potential
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problems. The plan will specify the required frequency of the uecessary monitoring such
as mine water level, seepage volume and evidence of strUctural stability o~ bulkheads, and
stability of the waste rock piles and will set forth procedures for resolving failures such as
pump failures, power outages or strUctural failures. The inspection and maintenance plan
will set forth contingency adions required for each key facility at the Site. Th.e plan will be
submitted to EPA for approval within six months of the signing of this ROC.. It will be
impl~ immediatelY UPOD EPA appluval. .
The present value cost for this alternative is $40,300 which represents an annual cost of
$2,300 for 30 years. There are no capital costs associated with this alternative.
tQSIS
Costs for the selected remedy are shown in Table IX-l.
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TABLE 0(.1
ESTIMATED COSTS OF Se..ECTED REMEDY
EAGLE MINE SEEPAGE croE CAAlNlCIVERSION)
~ Costs
T 08 CnlinlCiv8r.Iian System
c...IIiI.g8I rt:f @ 2St)(,
O~1IIian 8nd M8int8nMC8
l~anitortMairain
(Annual)
$102.360
$25.590
$127.950
$17.530
$17.530
eAGLE MINE SEEPAGE TCICIV SUBTOTAL (NPV a 5%. 10 YEARS)
$263.300
EAGLE MINE SEEPAGE (EXTRACT10N WEL.L.ALT.)
Capital Costa
Exrradion Well Field
Cutctf Wall
Contingency @ 25%
o~~ 8nd M6int....c:e
~awerfMainb1nanC8
SampleiAnatyz8
$38.330
$45.000
$20.833
$104.163
$11.565
$5.660
$17.225
EAGLE MINE SEEPAGE (EXmACT10N WE1..1.ALT.) SUBTOTAL
(NPV @ S%. 10 YEARS)
ROASiER PILE SURFACe WA"TER
~itaI Costs
WmeirwegBtaSion
Contingency @ 25t)(,
Openmon and Maintenance
Maintain fllVegetabon (5 yrs. NPV)
Insped/Sample (10y~. Npv)
ROASTER PILE SUBTOTAL (NPV @ 5%. 10 YAS)
$19.450
$4.863
$24.313
$37.042
$29.846
$66.888
$91.200
$241.100
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TABLE IX-t, cantInu8d
WASTe ROCK PtLESIBa.DEN NON-POINT SOURCES
Capital Co8t8
1ns1811 '4Nll8lSampI..
ConIingtnCy @ 25%
$68,980
$17.245
S86 "!i
.
O~ and M8int8l18nC8
S8mp1e(An8yz8 (Annu8)
$12,920
$12.920
WASTe ROCK SUBTOTAL (NP'I @ 5,," 10 YEARS)
$186,000
REX FlATSIOrP AREAS
Capita! Costs
InsI8iI 'MIter supply
~ltUlg"'f:f @ ~
$212,000
$S3.0D0
$265,000
Operation and Maintenance
SampA8/An8yze (Annual)
$2.430
$2,430
REX FlATSIOTP SUBTOTAL (NPV as%, 10 YEARS)
$284.000
CONSOUDA1'EJ TAiUNGS PILE
Capital Costs
Diversion Trench
ReIocat8 Minturn Well
1ns1811 Monitoring Well
Compl8t8 Pile Cap
ExtnIction Trench/Piezometers
Contingency @ 25%
$7.500
S22.SOO
$10,000
$472.800
$6.800 .
$129.900
$649.500
Operation and Maintenance
Monitoring/Analysis (Annuai).
Administration/Regulation (Annuai)
. 53.000
$2. 000
$5.000
CONSOUDAT'ED TAIUNGS PILE SUBTOTAL (NPV @ 5%, 10 YRS)
$679.000
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TABLE 1X-1, ccntinu8d
WA'TEFt TREATMENT PLANT .
c.,itaI Costs -
Sludge 08W8t8rin9 System
Sludge O~ Cell
Conting8ftCy @ 25"J'
$500,000
$1,663.900
$S4O.97S
$2,704,815
OP8f8llcn 8nd M8-d881811c8
T,.....
Sludge 0-"";'19
Sludge St8b3:. _I~ -and Oispas8
$1 ,2DO.OCO
$170.000
$33.000
$1,403,000
WATER TREATMENT' PlANT SUBTOTAl (NPV @ 5%, 10 YEARS)
MALOIT PARK WETtJ.NOS
Caf)it8I Costs
- AemovaUTopsai1lRevegetata
Contingency @ 25%
$339.300
$84.825
$424.125
Op8t8licn and Maint8nanC8
U..;. ~ ICe (3 y-=-. NP'I)
$17.030
$17,030
MALOIT PARK WETlANOS SUBTOTAl (NPV @ 5%. 10 YEARS)
BIOLOGICAL MON1TOAtNG Pt.AN
c.,itaI Costs
Stann W81111 Sarnpter.t
Contingency @ 25% -
$64.000
$16.000
$80,000
Operetion and Maintenance
Sampling and Anatysis
$390.000
$390.000
BIOLOGICAL MONITORING SUBTOTAL (NPV @ 5%. 5 YEARS)
INSPECT10N ANO MAINTENANCE PLAN-
Capitai Costs
Maintenance Plan preparation
$5.000
$S.aco
Ooemon and Maintenance
Bulkhead Inspection
S2.3CO
$2.300
INSPECTION AND MAINTENANCE SUBTOTAL (NPV @ 5%, 30 YEARS)
SELECTED AE.\iEDY TOTAL
$13.609.000
$449.600
$1,772.000
$40.300
$.17,374,400
-------
o ,
x.
STATUTORY DETERMINATIONS
The selected remedy satisfies the requirements of Section 121 of Superfund Amendments
and ,Reauthorization Act' of 1986 (SARA). SARA requires that Superfund remedial actions
be protective of human health and the environment. SARA also mandateS that the selected'
remedy attain applicable or relevant and appropriate environmental standards established
under Federal and State environmental laws except in ,those circumstances where a waiver
is justified. In addition, the selec:ed remedy must be cost-effeCtive and utilize permanent
solutions and treatment technologies to the maximum extent practicable. SARA also
expresses a strong preference for remedies that as their principal element employ treatment
technologies that permanently and significantly reduce the volume, toxicity, or mobility of
the hazardous substances. Th~ :folloWing '5ectlonS describe how the seleCted remedy
addresseS these SUltUtnty provisions.
Protection of '6uman Health and the Environment
The selected remedy addresses protection of the principal biotic resource' of the Eagle
River-cold water aquati~ life that has been impacted by m;n;ne activities. The remedy,also
provides for ~e rehabilitation of an existing wetland and the revegetation of the highly
disturbed areas at Rex flatS, Old T~mng5 Pile, and the Roaster Piles. The selected remedy
also addresses three major concerns related to human health, Le., the safety of dnldren and
employees attending the Minturn Middle School; the use of Minturn's municipal water
system; and potential use of area ground water polluted by mining activities. EP A risk
analysis has shown that PCBs (polychlorinated biphenyls) left in the' now-flooded Eagle
Mine pose no significant threat to human health.
The Superfund decision-tJ'I~1cing process will address additional human health concerns as
part of Operable Unit 2. OU-2 includes further efforts to define potential risk: from use
of private drinking water wells in the Minturn area; from possible metal contaminated soils
in the south end of Minturn and in Gilman; and from the waste rock piles.
Metals loading to the Eagle River from the mining and milling activities is very complex.
Visible and subsurface mine seeps, waste rock piles, alluvial ground water, and leachate
from the tailings all contribute to the metals load in the river. The metals loading changes
on a seasonal basis and is probably impacted by daily storm events. The extensive
monitoring accomplished to date has yielded a basic understanding of the major sources of
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. .
loading. but the results of the completed and ongoing remedial actions will require
. . continued monitoring to fully evaluate their impact.
The selected remedy protects the environmental resources of the Site by further controlling
the metals loading which presently impacts the Eagle River. The mine seepage In the Rock
Creek area continues to be the principal source of metals loading to the Eagle River. The
selected remedy provides for continued collection of the surface mine seepage and, as
additional components, will: intercept subsurfaa: flows in the Rock Creek drainage by
collecting colluvial see~age in a toe drain, and use a culvert to divert clean Rock Creek.
surface water directly into the Eagle River. As a process option. EP A will consider
proposals to implement.an enhan~d extraction well process option, if it can be shown to
adequately collect subsurface flows from .the Rock Creek colluvium and that additional
upgradient seep collection is not required. following mine pool drawdown.
The contaminated leachate/groundwater originating from the CfP will be collected and
treated from the enhanced extraction trenches until it can be demonstrated that such
. collection and treatment is not needed to continue to meet the Eagle River Final
Remediatio~ Goals. .The capping of the CfP will be completed within two years and th.e
water treatment plant sludge will be dewatered and disposed in . lined disposal cells
COWttulcted at the CTP. The capping of the CTP, the dewatering of the sludge and
implementation of a lined disposal ce~ combined with. upgPtiient groundwater diversion
will significantly reduce the amount of water contributing to the crP groundwater regime
. and ultimately to metals loading in the Eagle River.
The metals loading from the Old Tailings Pile improved as the result. of tailings removaL
application of lim~ and topsoiling. At the Old Tailings Pile the seleCted remedy seeks to
ensure successful revegetation. Metals loading from the Roaster Pile area will be further
reduced' by ensuring successful revegetation. The Rex Flats metals loading caused by snow-
melt and other storm events will also be controlled through further revegetation.
Restoration of the Maloit Park wetlands will be accomplished by removing the outwashed
tailings and placing them in the CfP. The action will improve the quality of the wetlands,
eliminate potential exposure to tailings contaminated sedimentS and reduce metals loading
to the Eagle River.
a
Human health will be protected through complete capping of the Consolidated Tailings Pile.
To eliminate the potential degradation of existing groundwater quality, new Minturn
- . .
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drinking water wells will be ~tal1ed at an upgradient location so that drawdown during .
heavy use cannot cause cont~m;n~nts from the CI'P to be drawn to wells.
Institutional controls to restri~ the use of groundwater at Rex Flats, the Old Tailings Pile,
and the Maloit Park areas will be pursued. Application of Eagle County zoning authority
to control development of the areas where t~mngs have been removed will also be pursued.
State regulations m conjunction with local zoning authorities will protect the integrity of the
Consolidated T~mn~ Pile cap.
Implementation of the selected remedy will not pose any unacceptable short-term risks or
cross-media impacts.
Under Section 121( d)(l) of CERcu, remedial actions must attain standar~ requirements,
limitations, or criteria that are "applicable or relevant and appropriate" under the
circumstanCeS of the release at the Site. The ARARs that have been selected for the Eagle
" .
Mine Site are listed in Table X-l and Table X-2. In addition, there is another category of
information that was used in .the ROD decision-making process- .known as "To Be
Considered" (TBC) guidelines. TBCs are also provided in Tables X-I and Table X-2. TBCs
represent Federal and State advisories, criteria or guidance that are not ARARs, but are
useful in developing CERCLA remedies.
The major ARARs selected for clean up of the Eagle Mine Site are:
water quality standards for the Eagle River
groundwater quality standards
standards regulating the disposal of water treatment sludge
EP A offers the following discussion regarding attainment of surface water quality ARARs
in the Eagle River. Although EP A believes the remedy selected in this ROD will meet the
in-stream ARARs, these values probably will not be met until all of the components of the
remedy are finished. In all likelihood it will take many years for the results of the remedial
actions to take full effect. For this reason, continued monitoring of the Site will be
necessary to track the continued progress towards compliance. In addition, continued
monitoring will be essential to the review and potential future modifications of the remedies
so as to maximize their beneficial impact. In summary, it will nOt be until the"full beneficial
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effects of the multiple remedial components are brought to 'bear, in concert, that surface
water quality goals will be attained.
To that end, EP A, in conjunction with the State, will pursue an "Eagle River Biological
Criteria Approach" to define what would comprise an acceptable range of aquatic life in
Segment 5 of the Eagle River (for e.~'"Ple, a full aquatic commnnity, a viable self-sustaining
fishety, etc.). EPA will encourage the State will invite federal trustees, Paramount, local
goverDment ami the public to participate in a liaison group to discuss the issues and remain
informed of studies and results. The group will not present any decisions to EP A
However, the EP A and State cannot abrogate any legal role-ma kine or other legal.
respons1Oilities for the fiDal decision as to the use classification of Segment s. In the process
of determining the definition of a viable aquatic community, this approach may also
. .
participate in the development of water quality standards for segments of the Eagle River.
As sta~ the Eagle River will continue to be monitored. This monitoring will inc1ude
m~t!:tlc load 1;Dl\nitoring... evaluation of trends and changes in the system as controls are
implemented, and biological monitoring. The biological monitoring will evaluate the ar.t11aI
biological respOnse of the river biota to metals loading.
five Y ear ~eview
EPA is required to review the "protectiveness" of its clean up measures selected in a ROD
at a S-year point starting from when remedial a~on commenced. Throughout the ROD
process on the Eagle Mine Site, EP A has stated it wOuld consider post-ROD solutions to
Site problems if they could be shown to be equally or more protective, more effective, more
cost-effective, etc:., than the EP A remedies selected in this ROD. Paramount is currently
studying the effectiveness of the use of biological water treatment as a remediation system
for mine seepage. EP A finds this system to have potential merit but the development of a
biological treatment system is now only in the "prototype" state. If Paramount can show this
type system meets all CERClA evaluation criteria then EP A will consider a modification
to its ROD, possibly at the S-year review period or even at an earlier date. If EP A decides
that wetlands treatment system will be implemented, EP A will advise the public by means
of a document and process called an "Explanation of Significant Differenc~s" (ESD). An
ESD explains significant changes that are made to a ROD and setS up a process, including
public involvement, to make these changes, if warranted.
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Another significant alternative that may be addressed by Paramount in the future is an
evaluation of the posSl"bility of intercepting clean water in-flow into the Eagle Mine. EP A
, evaluated this alternative in its Feasibility Study Addendum but did not have sufficie,nt
information to fully evaluate this as a pOSSl"ble component of a remedial alternative. If it
can be shown that reduction of in-flow lowers the mine water level sufficiently to reduce the
volume of seepage from the mine, less cont~mina.ted seepage would require treatment. This
would result in a corresponding decrease in quantity of sludge requiring disposal. EP A will
consider in-flow reduction alternatives on their merits and encourages Paramount to collect
the necessary data to evaluate this concept.
Cost Effectiveness
To ensure that a cost effective rem~dy was selected, EP A sought to understand the relative
, conuibution of the various source areas to the metals load in the Eagle River. In this way,
undue emphasis on small sources with tninima1 contribution to metals loading could be
. avoided, and remedial o~jectives developed accordingly. Funher, where alternatives provide
equivalent protectiven~ the low cost alternatives were given added weight in the selection
process. As a result of this approach, the sel~cted remedy provides overall effectiveness
which is proportionate to the coStS. and bas avoided commitment to expensive, large scale
activities where the data is inconclusive.
~:~= !>UPTm2ft!:J1t :>a-tel and....l!)t;rnarive T1'e1Itmettt T~nolo~es to the
. fYtp-nt ~Preference for Treatment as a Principal Element .
In ,selecting the remedy for the Eagle Mine Site EP A has urili7-ed permanent solutions and
alternative ueaunent technologies to the:naximum extent practicable. This is a challenging
mandate at mine sites given the sources. the types and the distribution of the contaminants.
In selecting the remedy for the Eagle Mine Site EP A identified and screened alternatives
whi~ as a preference, include ueatment as a principal element. Because of the continuous
nature of the sources at the site, source conuol was selected over treatment. However, the
remedy does include continued operation of the water treatment plant. Water treatment
represents a reliable approach which contributes substantially to achieving Site goals and
to some extent permanently reduces the volume and mobility of waterborne contamination
from a wide variety of sources at the Site.
~itional ROD Components
Based upon the comments received on the FSA and proposed plan and further internal
review by. EP A specialists, EP A has determined that it is appropriate t~ identify tWO
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additional remedial components in the ROD for Eagle Mine Site. The first is the
development of a Biological Monitoring Plan which is required to support the work of the
biological criteria approach and provide evaluation of the effectiveness of remedial actions.
The second is preparation of an Inspection and Maintenance Plan which addresses the need
for inspection. maintenance, and emergency preparedness associated with stnlctures and
facilities related to the remedial actions at the Site.
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TABLE X-I
CIlEMICAf,SPECIFIC ARARS AND TO BE CONSIDERED GUIDELINES FOR
THE EAGLE MINE FACILITIES
Applicable or
Relcya.t a.d
Slandard., Rcqulrement., . Appropriate or To
Crtlerill. I.Imllllllnns ~lIalioD f)eKl'iotl.D Be CODlldeu4 Commeat
OROUNOW A TER:
Colorado Groundwater S CCR 1002-8, Section 3.11. Proted' edstins and potential Relevant and Appropriate to The St..e of Colorado Jau aOt
Standards beneficial uses of desipated Site sroundwater.. dusifieCt Site pOODdwater.
Ifoundwater rCloun:CI. ThelO dauificatioaa reprClCDt
.80D-binclin& indepcadeat EPA
dcterminadoDl.
~URFACE WATER:
Colorado Water Quality S CCR 1002.8, II 3.1.0 to EstablishClsegmentcd. AppUcable or relevant and The relevant and appropriate
Standards 3.11.8. beoefidal use-specific appropriate to Site surface Colorado Table Value.
dauificatloDl and year-round waters. Stancluda wero adopted at tho
water quality ~t8Ddards for Ymal RemediatioD Ooali.
surface waters. The cxislin" appUcabio water
quality standarda for Scsmeat
S of the Eagle River uc Dot
protective 01 the f;Ulfeot
bcnefidal use dcsiaaatioD and .
do oot reprcscot usable
remedial 80als.
~
Interim Guidance on EPA Directive 19155.4-02, Eslablisbel pidancc cleanup To-Be-Considered auideUnel. Adopted u the remediadoa
Establishing Soil Lead September 1989. leVtIs for lead contaminated loal for Sile lOlls.
Cleanup Levels at Superfund soils.
Sites
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TABLE X-l
ACfION AND loCATION-SPECIFIC ARARS FOR TilE EAGLE MINE FACIUTIES
Slaadurds, Requlremenls,
Crtlerlu. Umlli,lIons
Cllalloa
~OLlD AND HAZARDOUS WASTB MANAGEMBNT:
Colorado Wasle Facilily Si!ing 6 CCR 1001.2
,Rules
, Colorado Standards for
Owners and Operators of
hazardous Waste Treatment,
Storage, and Disposal
facilities
plSCHARGB OF WATER:
Colorado Pollutant Discharge
Elimination System
fll-UNO Of WETIANOS;
Dredge or fill Requirements
(Section 4(4)
6 CCR 1001-3 Part 264,
. Subpart N
S CCR 1002-2, II 6.1.0 10
6.18.0.
40 C.f.R. Paris 230, 231
33 C.f.R. Pari 323, pursuant
to 33 U.S.C. . 1344
pelcrlnlloa
Eslabliibca lIaDduds for
disposal of 8oo.bazardoua
solid WallCl. '
'Standards for aianagemenl of
bazardous waste attre.lmeDt,
storlie, and disposal facilities. '
Rcquires permits for the
dilChuge of pollutants from
any pomt louree mto waters of
Ibe United States.
Requires permits fo~ discharge
of dredgcd or fill material into
navigable waters.
POlea...II, Applkable or
Relltvaal aad ADafoDriatc
Applicable.
Relevant, and appropriatc.
Applicable.
Relevant and Appropriatc.
~olDmeDI
~pplic:ablc to siUag of 8CW
. facility for off&itc dispoul of
watcr .,cllmenl sludae.
Pursuanlto the rulca Ibc
disposal of liquida ia landfalls
II prohibited.
1110 Subpart N laadfiU
requircmenll arc rclcYaal aad
appropriatc to,tbe
1D1D88CIDCnl of mbae lai1iap
ia Ibc CoDIoIidalcd TaWap
Pile. ,
, The wiler Ireatmenl pIanI
must be d~i8Ded and
opcrllcd 10 meel Colorado
Wiler Quality Slaawda u
AltAR. Each lOurce area wiD
be monitorcd and cvaluated 10
determiDc tbe applicability or
rclevance and appropdatencu
of Ibc Itorm water rcgulatiou.
Where remediation activitiel
cffecl wetlands, tbe mitigation
obligation imposed by Section
404 will be auained.
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TABLE X-l, continued
ACfION AND LOCATION-SPECIFIC ARARS FOR TIlE EAGLE MINE ~ACILITIES
StlDdlirds. Requirements.
Crlle".. Umlhilions
MINE REVEGETATION:
Colorado Mined Land
Reclamation Rcgulalions
fisb and Wildlife
Coordination Act
Cllalloll
pcsmollo8
2 CCR 407,1
Establishcl Mioed Land
Reclamation Requirementl.
16 U.S.C. II 661-666
Requires consultation when
federal depulmeol or aaeocy
proposcs or aulborizes any
modificalion of any Ilrcam or
otber walcr body to provide
for adequate provision for
prolection 01 fish ~nd wildlife
rClourcel.
40 C.f.R. I 6.302(g) .
.,
PoteDtlall, Applicable or
Relevant IDd AODl'qorlalc
Relevanl aod Appropriale.
Relevant and Appropriatc.
~ommelll
Relevanllo revcgelation 01
uea whcre lailings havc.been
removed.
Prior 10 modification of waler
bodies appropriate agencies
wiD be coDSulted.
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