305896

WE Ref: 8HWM-S R

ACTION MEMORANDUM- - ENFORCEMENT

DATE : August 4, 1995

FIL E FLAN

 2

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SUBJECT: Request for Removal (Response) Action at the California Gulch National Priorities List Site , Leadville , Colorado: ACTION MEMORANDUM for PRP Financed Removal Action at the Garibaldi Mine Site , Operable Unit 4 ( OU 4)

FROM: Sam Vance, 8HWM-S R

T O: Robert L. Duprey, Director Hazardous Waste Management Division

Final NPL Sit e ID # 29

CERCLI S ID # COD980717938

Category of Removal: Non-Time Critical

I . Purpose

Thi s Action Memorandum documents the Agency' s decision to

conduct the Removal (response) Action described herein for the Garibaldi Mine site portion of OU 4. The Garibaldi Mine site

is an area which has been contaminated by the mine waste

piles , mill tailin g and fluvial tailing material from historic

mining and millin g operations. The evaluation of alternatives

available to address this area are contained in the final

Engineering Evaluation/Cos t Analysi s (EE/CA ) for the Garibaldi Mine Sit e within Upper California Gulch Operable Unit 4, California Gulch Superfun d Site , Leadville, Colorado which is

dated Jul y 1995. The EE/CA was prepared by Resurrection Mining Company ("Resurrection"), Denver, Colorado for a

portion of the California Gulch Superfun d Sit e (Site ) within

its "area of responsibility" as defined by the August 26, 1994

consent decree between the United State s and Resurrection.

The Removal Action at the Garibaldi Mine site is consistent

with the overall remedial activities to be undertaken by Resurrection at OU 4. As such, the Removal Action

alternatives evaluated in the EE/CA are considered to

represent interim response actions, but the removal

alternatives will also be evaluated as final remedial

alternatives in the Feasibilit y Stud y (FS) and Record of
CONCURRENCE COPY

Ref: 8HWM-S R

ACTION MEMORANDUM--ENFORCEMENT

DATE : August 4, 1995

SUBJECT: Request for Removal (Response) Action at the California Gulch National Priorities List Site , Leadville, Colorado: ACTION MEMORANDUM for PRP Financed Removal Action at the Garibaldi Mine Site , Operable Unit 4 ( OU 4)

FROM: Sam Vance, 8HWM-SR

T O: Robert L. Duprey, Director Hazardous Waste Management Division

Final NPL Site ID # 29

CERCLIS ID # COD980717938

Category of Removal: Non-Time Critical

I. Purpose

Thi s Action Memorandum documents the Agency' s decision to

conduct the Removal (response) Action described herein for the Garibaldi Mine site portion of OU 4. The Garibaldi Mine site

is an area which has been contaminated by the mine waste

piles , mill tailin g and fluvial tailin g material from historic

mining and millin g operations. The evaluation of alternatives

available to address this area are contained in the final

Engineering Evaluation/Cos t Analysi s (EE/CA) for the Garibaldi Mine Sit e within Upper California Gulch Operable Unit 4, California Gulch Superfun d Site , Leadville , Colorado which is

dated Jul y 1995. The EE/CA was prepared by Resurrection Mining Company ("Resurrection"), Denver, Colorado for a

portion of the California Gulch Superfun d Sit e (Site ) within

its "area of responsibility" as defined by the August 26, 1994

consent decree between the United State s and Resurrection.

The Removal Action at the Garibaldi Mine site is consistent

with the overall remedial activities to be undertaken by Resurrection at OU 4. As such, the Removal Action

alternatives evaluated in the EE/CA are considered to

represent interim response actions, but the removal

alternatives will also be evaluated as final remedial

alternatives- n the Feasibilit y Stud y (FS) an d Record of
Decision (ROD) for OU4. The Removal Actions are not intended

to be final actions, but are rather intended to contribute to

the efficien t performance of the remedial actions for OU 4. The ROD for OU 4 will ultimatel y determine whether further

remedial actions are required.

The primary goal of this removal action is to reduce the risk

to the aquatic and terrestrial ecosystems by reducing the

release of contaminated material into the environment from the Garibaldi Mine site. Thi s removal action will also reduce the

potential for leaching and migration of metals from the mine

wastes into surface and ground waters.

Remedial action objectives were identified in the Final Screening Feasibilit y Stud y for Remediation Alternatives at

t he California Gulch NP L Site , Leadville, Colorado (SFS) ,

(EPA, 1993a) . Consistent with the SFS, removal action

objectives for the Garibaldi Mine Sit e are:

O Control wind and water erosion of waste rock

material from the source locations

O Control leaching and migration of metals from waste

rock into surface water

O control leaching and migration of metals from

waste rock into groundwater

Removal alternatives to directl y remediate surface water or

ground water in the vicinity of the Garibaldi Mine site are

beyond the scope of this EE/CA . Consistent with the Consent Decree and Work Area Management Plan (WAMP), Applicabl e or Relevant and Appropriate Requirements (ARARs) specifi c to

surface water and groundwater are not included as performance

standards for evaluation of this response action.

I I. California Gulch Sit e - Conditions and Background

T he California Gulch Sit e was listed on the National Priorities List on September 8, 1983. The Sit e is in a mining

area covering 16 1/2 square miles of a watershed area that drains along California Gulch to the Arkansas River. Startin g

in 1859, the area was mined extensively for gold, lead,

silver, copper, zinc, and manganese. California Gulch

collects runof f that drains numerous abandoned mines and

wastes from mining, millin g and smelting. Seventy-five known

mill s dumped tailings into 5-6 miles of drainages and 6 impounded tailings dumps surround the Cit y of Leadville. Many

smelters operated at various times around the Cit y processing

silver, lead, and zinc. Heavy metal residues are present in

much of the City . The Arkansas River which.receives water
from the California Gulch, has been classified as a

recreational resource, and is used heavily for irrigation,

livestock watering, public water supplie s and fisheries . Approximately 4,000 live in nearby Leadville and Lake County.

(See Site Location Map - Figure 1)

III. Garibaldi Mine Sit e - Conditions an d Background

T he Garibaldi Mine site (Se e Figure 2) is located near the

headwaters of California Gulch. The Garibaldi Mine site is

located approximately three miles southeast of the Cit y of Leadville and is part of Operable Unit 4 (OU 4) of the Site . OU-4 is defined as the area hydrologicall y drained by California Gulch from immediately upstream of the Yak Portal

to the headwaters of the gulch. Prominent features at the Garibaldi Mine site include a waste rock pil e covering an area

of approximately 1.6 acres and a collapsed mine portal . A

steam engine and other mining remains are located adjacen t to

the collapsed portal . Run-on diversion channels have been

constructed by the Resurrection/ASARCO Join t Venture around

the waste rock pile. In additional , a portion of the tunnel

discharge is currently diverted around the pile.

Samplin g of surface water, groundwater and stream sediments

indicates that mining activities may have produced acid mine

drainage and heavy metal contaminations which have impacted

these media. Remedial investigation activities identified

fluvial tailin g and waste rock piles as areas potentiall y

requiring remedial action within OU 4.

B. Other Action s to Date

In 1990/1991, Resurrection/ASARCO Join t Venture

constructed run-on diversion channels around the waste

rock pile and a portal discharge diversion. Also , the

dirt road above the Garibaldi tunnel portal was

reconstructed to convey storm water on the uphil l part

(north side) of the road instead of allowing the water to

flo w across the road and downhill into the mine waste

rock area. The ditches were designed for a 25-year, 6 hour storm event.

C. Stat e and Local Authorities Roles

O The EE/CA was issued for public comment and a public hearing was held to discuss this Removal Action . No substantive comments were received.
O Cultural Resources Concern: On June 29, 1995

t he Stat e Histori c Preservation Office r (SHPO )

commented to EPA on the historic significance of Sit e 5LK805 . At that time, SHPO confirmed that the

resource did not contribute to any proposed

expansion of the Leadville National Historic Landmark District. SHPO further determined that

EE/CA alternatives A and B would have no effec t on

t he qualities of significance of the Leadville Mining District within which the Garibaldi Mine Sit e

is located. Since this action utilizes activities

only within alternatives A and B, no impact to

cultural resources will result.

O City of Leadville: EPA has notified the citizens of Leadville by the release of and acceptance of public

comment on the Engineering Evaluation/Cost Analysis

(EE/CA) concerning this removal action. Under CERCLA § 121(e) , no Stat e or local permits are

required for the excavation since this is an on-site

action conducted pursuant to CERCLA Section s 104 and

122.

I V. Threat s to Public Health or Welfar e or the Environment,

and Statutor y and Regulatory Authorities

A Draf t Final Baseline Aquatic Ecology Risk Assessment

(DFBAERA) , California Gulch, Leadville, Colorado (Roy F. Weston , Inc. [WESTON] , 1994) identifie s the Site-wide impact

of mine waste contamination on the terrestrial and aquatic

ecosystems at the Site . The DFBAERA provides a conceptual

model of Site-wide exposure for aquatic receptors.

Seeps and mine portal discharge contain low pH and elevated

metals. Mine waste contains lead, arsenic and zinc. Leachate

is highly acidic and has elevated levels of zinc, cadmium,

iron, lead and sulfate . Thi s leachate is similar to seep

water collected at the toe of waste rock pile and downstream

in California Gulch.
V. Endangerment Determination

Actual and/or threatened releases of hazardous substances

from the Garibaldi Mine site, if not addressed by implementing

the removal action selected in this Action Memorandum, may

present an endangerment to public health, or welfare , or the

environment.

V I. Proposed Actions/Performanc e Standards/Estimated Cost s

A. Proposed Actions (Se e Drawing No. 3)

1. Four channels would be constructed (approximately

1,960 feet) . Diversion Ditch 1, located along the

southern edge of the waste pile would divert runof f

around the waste rock pile and into Diversion Ditch 2. Ditch 1 would not be lined. Diversion Ditch 2, located along the northeast edge of the

waste rock pile , would divert runof f from Diversion Ditch 1 and the eastern stream channel around the

waste rock pile to Diversion Ditch 4. Diversion Ditch 2 would be routed through a 36-inch culvert

under the existing access road. In addition ,

drainage from the existing collapsed portal and from

the eastern groundwater interceptor trench

(discussed further below) would be routed through Diversion Ditch 2. Diversion Ditches 2 and 4 would

be concrete lined. Diversion Ditch 3, located along

the existing access road northeast of the waste rock

pile , would divert runof f along the northeast end of

the pile to Diversion Ditch 4. Diversion Ditch 3 would be lined with rip rap. Diversion Ditch 4,

located along the existing access road on the north

side of the waste rock pile , would collect runof f

from Diversion Ditches 2 and 3 and the north stream

channel, and route the flo w around the pil e to the

natural stream bed. Diversion ditch 4 would also

convey flo w from the northern groundwater

interceptor trench (discussed further below) . Two

36-inch culverts would be installed in the upper

portion of Diversion Ditch 4 to route the runof f

under the existing access rod. A 48-inch culvert

would be placed at the end of Diversion Ditch 4 to

convey the runof f back under the existing access

road and down the steep slope to the natural

drainage. An energy dissipater would be required at

the end of the 48-inch culvert.
2. Two groundwater interceptor trenches would be

constructed, as shown in Drawing 3. The groundwater

interceptor trench for the eastern channel would

divert flo w into Diversion Ditch 2. The groundwater

interceptor trench for the northern stream channel

would divert flo w into Diversion Ditch 4. The

interceptor trenches would be approximately 3 feet

wide and approximately 10 feet deep, down to

bedrock. The trenches would consist of a gravel

drain back-lined with a high density polyethylen e

(HOPE) liner. A filte r fabric would be installed

around the clean gravel to reduce siltatio n and

clogging. A perforated PVC pipe would be connected

to a solid PVC pipe which would tie into the

diversion channels, as shown on Drawing 3. The

interceptor trench would be keyed into bedrock, as

conditions allow.

3. Best Management Practices (BMPs) would be utilized

during all construction activities at the Garibaldi Mine site. Temporary sediment control structures,

including placement of straw bales, sediment control

fences , or small berms would be utilized to control

sediment runof f from the area, In addition, dust

control, (includin g the use of a water truck) would

be practiced during construction.

B. Applicabl e or Relevant and Appropriate Requirements (ARARs)

ARARs are identified in Appendix F of the EE/CA . They will be met by implementing the Performance Standards

identified in Sectio n C.

1. Chemical Specifi c ARARs -

Chemical-specific requirements are based on

health or risk-based concentration limits or

discharge limitations in environmental media (i.e.

water, air) for specifi c hazardous chemicals. These

may be used to set cleanup levels for chemicals of

concern (in this case, metals) in the designated media, or to set a safe level of discharge (e.g.

waste water discharge, taking into account water

quality standards) where a discharge occurs as part

of the removal activity.
2. Action Specifi c ARARs -

2.1 Clean Air Act

2 .2 Clean Water Act - National Pollutan t Discharge Elimination System

2 .3 Colorado Air Quality Act

2.4 Colorado Mined Land Reclamation Act

2 .5 Colorado Noise Abatement Act

3 Location Specifi c ARARs -

3 .1 National Historic Preservation Act

(Se e Stat e an d Local Authorities Section )

3 .2 Clean Water Act (Sectio n 404)

3 .3 Fish and Wildlif e Coordination Act

3.4 Executive Order 11988 on the Protection of Floodplain s

3.5 Executive Order 11990 on the Protection of Wetlands

C. Performance Standards

The ARARs are being met through the Performance Standards . Performance Standards shall be attained

consistent with ARARs and EPA approved removal action. T he Performance Standards are described below:

1. The response action as designed and constructed

shall include provisions to ensure that there are no

visible emissions (dust ) from the Garibaldi Mine

site during and followin g construction of the

removal action.

2. The response action as designed and constructed

shall include provisions to ensure that there is no

erosion of the tailings materials or sediments due

to rain or snow melt.
3. The design shall contain requirements to ensure

that erosion, run-on, and run-of f are prevented and

to ensure slope stability . Rain, flood and snow

melt shall not be allowed to run onto or from the

tailings area. All slopes shall be graded to be

permanently stable.

4. A long-term maintenance program may be implemented,

if required by the final ROD for OU 4, to ensure the

long-term effectivenes s of this response action.

D. Project Schedule

T he Project Schedule will be documented in the

EPA-approved removal action Work Plans. The construction

of this removal action should be completed by November

1995. Upon completion of construction of the removal

action and attainment of the Performance Standards , longterm maintenance and monitoring will be initiated, if

necessary.

E. Estimated Costs

As provided in the final Engineering Evaluation/Cos t Analysis , Final Revision dated Jul y 1995, the estimated

cost for the removal action described is $219,379. The

estimated cost of long-term maintenance and monitoring

for a 30 year period is no known at this time.

VII. Expected Change in the Situatio n Should Action Be Delayed or N ot Taken

Should this removal action be delayed, or not taken at all , a

potential risk of exposure to heavy metals contained in the

mine waste, groundwater and surface water will continue to

exist.

VIII . Outstanding Policy Issues

A Record of Decision will be issued for OU 4 of the Sit e

selecting the final remedial action for the Garibaldi Mine

site portion of the Site .

I.. Enforcement

Resurrection Mining Company is the party that has agreed to

implement response actions for the OU 4 portions of the Site .
X. Re commendat i on

Thi s decision document represents the selected Removal Action

f or a portion of OU 4 of the California Gulch Superfun d Site ,

in the Cit y of Leadville, County of Lake, Stat e of Colorado. It was developed in accordance with CERCLA, as amended, and is

not inconsistent with the NCP. Thi s decision is based on the Administrative Record for the Site .

Conditions at the Garibaldi Mine site meet the NCP Sectio n

300.415(b)(2 ) criteria for a removal and I recommend approval

of the proposed removal action.

APPROJZAL

Robert L. Duprg Hazardous Waj5r£e xManad;em'ent Division

DISAPPROVAL

Robert L. Duprey, Director Hazardous Waste Management Division
•T

NOT TO SCALE

CALIFORNIA GULCH SUPERFUND SITE

Project No.:

664-0100

File:

RESWLOC.DWG

Design By: J.RAY

Drtiuin By: K.CONRATH

RESURRECTION MININ G COMPAN Y O N E UNITE D BAN K CENTE R 1700 LINCOLN STREET DENVER , COLORADO 60203

Scale:

N/A

Date.:

JUNE 1995

FIGURE 1

CALIFORNIA GULCH SITE

GENERAL LOCATION
GARIBALDI MINE SITE (Refer To Drawing 1 For Details )

sex;/.£

0 2.500' 5,000'

SCALE r.- s.oooLEGEND

V OPERABLE UNIT 4

C G A I G SURFAC E WATE R MONITORIN G LOCATIO N

Project No.; 884-O1OO

File: OU-AREA4.DWG

Design By: J.HAY Drawn By: T.LEVtCH

RESURRECTION MININ G COMPAN Y O N E UNITED BAN K CENTER 1700 LV4COLN STREET DENVER, COLORADO tOXX

Scale:

r * sooo- Date:

JUNE 1995

FIGURE 2

GARIBALDI MINE SITE EE/CA

OPERABLE UNIT 4
LEGEND

CLEA N GRAVEL -

HOPE LINER -

DIVERSION 01TCH

LIMIT OF WAST E ROCK

CULVER T

PORTA L

ACCES S ROAD

GROUNOWATE R TRENC H

PIP E

FLOW DIRECTION

ENERG Y DISSIPATO R

SLOTTED PV C PIP E Note: IWIt l B e Keyed Into Bedrock A s Condition s Allow )

INTERCEPTOR TRENCH

FREEBOAR D i 0.3

TYPICAL UNLINED CHANNEL

CONTCU R INltRVA l

DRAWING No . WHER E - DETAIL/SECTIO N I S REFERENCE D

1 — — DRAWIN G N o WHE" E DETAiL/SECnO K I S SHOWN

DIVERS/ON DITCH SCHEDULE

DITC H

1

2

3

A UPPER

4 LOWER

PEAK DISCHARG E

(CFS I

0.4

23.0

11.0

39.0

62.0

SID E SLOP E

2H:1V

2H:1V

2H;1V

2H:1V

2H:1V

CHANNE L SLOP E W

2

2

17

16

11

VELOCIT Y

(FPS )

1.4

8.7

7.4

21.4

21.3

FLOW DEPT H IFT )

0.1

0.5

0-5

0.6

o.a

LINER

TYP E

GRAS S

CONCRETE

RIPRA P DSO=6"

CONCRET E

CONCRET E

FREEBOAR D = 0.3RIPRA P

-FREEBOAR D : 0.3

L ,J TYPICAL RIPRAP LINED CHANNEL ^TYPICAL CONCRETE LINED CHANNEL

JPROJECT N O

CALIFORNIA GULCH SITE

Garibaldi Mine Site

"DRAWIN G TITLE ; GARIBALDI MINE SITE AL TERNA TIVE B

RESURRECTIO N MININ G CO M O N E UNITE D BAN K CEHT£ «

OENVEO . COt.O"*OO 60203

DRAWING r\ a