Preparedfor: 305633

RESURRECTION MININ G COMPANY

1700 Lincoln Street Denver, Colorado 80203 FIL E PLAN

FINA L

ENGINEERIN G EVALUATION/COS T ANALYSI S

GARIBALD I MIN E SIT E WITHI N UPPER CALIFORNIA GULCH - OPERABLE UNIT 4

CALIFORNI A GULC H SIT E LEADVILLE , COLORADO

July 1995

Prepared by:

TerraMatrix Inc. Shepherd Miller, Inc.

1475 Pine Grove Road, Suite 109 1600 Specht Point Drive, Suite F Steamboat Springs , Colorado 80477 Fort Collins, Colorado 80525

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TABL E OF CONTENT S

Page No.

1.0 EXECUTIV E SUMMARY ......................................... 1

1.1 GENERAL BACKGROUND ................................ 1

1.2 PROJECT SCOPE AND OBJECTIVES ......................... 1

1 .3 REMOVAL ACTION ALTERNATIVES EVALUATED ............ 2

1 .4 RECOMMENDED REMOVAL ACTION ALTERNATIVE .......... 4

1.5 REPORT ORGANIZATION ................................ 4

2 .0 SITE CHARACTERIZATION ...................................... 6

2 .1 SITE DESCRIPTION AND BACKGROUND .................... 6

2.1.1 Site Identificatio n and Background ........................ 6

2.1.2 Regulatory Framework ................................ 6

2.1.3 Facilit y Type and Operational Status ....................... 6

2.1.4 Topograph y ........................................ 7

2.1.5 Pedology and Geology ................................. 7

2.1.6 Hydrology ......................................... 7

2.1.7 Surrounding Land Use and Population ..................... 9

2.1.8 Sensitive Ecosystems .................................. 9

2.1.9 Climate ........................................... 9

2.1.10 Historic and Cultural Resources .......................... 10

2.2 PREVIOUS REMOVAL ACTIONS ........................... 10

2.3 SOURCE, NATURE , AND EXTENT OF CONTAMINATION ...... 11

2.3.1 Identificatio n of Sources of Hazardous or Contaminating Substances ......................................... 11

2.3.2 Characteristics of Source ............................... 11

2.3.3 Physical and Chemical Attributes of Contamination ............ 14

2.3.4 Areas Affected ...................................... 25

2.4 RISK ASSESSMENT ....................................... 25

2.4.1 Scope of Risk Evaluation ............................... 25

2.4.2 Conceptual Site Model ................................. 25

2.4.3 Applicatio n to Garibaldi Mine Site Removal Action ............ 26

3.0 IDENTIFICATION OF REMOVAL ACTION OBJECTIVES ............... 27

3.1 STATUTORY LIMITS ON REMOVAL ACTIONS ................ 27

3.2 REMOVAL ACTION SCOPE, GOALS, AND OBJECTIVES ........ 27

3.2.1 Removal Action Scope ................................. 27

3.2.2 Removal Action Goals ................................. 27

3.2.3 Removal Action Objectives ............................. 27

3.3 REMOVAL ACTION SCHEDULE ........................... 28

3.3.1 Removal Schedule .................................... 28

3.3.2 Planned Activities .................................... 28

4 .0 IDENTIFICATION AND ANALYSIS OF REMOVAL ACTION ALTERNATIVES ............... 29

4 .1 ALTERNATIVE IDENTIFICATION AND INITIAL SCREENING ... 29

4.2 EVALUATION CRITERIA ................................. 31

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4 .3 ALTERNATIVE A - SURFACE WATE R AND PORTAL FLOW DIVERSION ............................................ 33

4.3.1 Description of Alternative A ............................ 33

4.3.2 Analysi s of Alternative A ............................... 34

4 .4 ALTERNATIVE B - SURFACE WATER , PORTAL FLOW, AND

SHALLOW ALLUVIAL GROUNDWATER DIVERSION .......... 36

4.4.1 Description of Alternative B ............................. 36

4.4.2 Analysi s of Alternative B ............................... 37

4 .5 ALTERNATIVE C - SURFAC E WATER , PORTAL FLOW, AND

SHALLO W ALLUVIA L GROUNDWATE R DIVERSION/REGRADING/SIMPLE COVER .................

4.5.1 Description of Alternative C ............................ 39

4.5.2 Analysi s of Alternative C ............................... 40

4.6 ALTERNATIVE D - WASTE ROCK REMOVAL ................. 42

4.6.1 Description of Alternative D ............................ 42

4.6.2 Analysi s of Alternative D ............................... 43

5 .0 COMPARATIV E ANALYSIS OF REMOVAL ACTION ALTERNATIVES ............... 46

6.0 RECOMMENDED REMOVAL ACTION ALTERNATIVE ................ 48

6.1 DESCRIPTION OF ALTERNATIVE B ........................ 48

6.2 RATIONALE FOR SELECTION OF ALTERNATIVE B ........... 49

6.2.1 Effectivenes s ........................................ 49

6.2.2 Implementabilit y ..................................... 50

6.2.3 Cost.............................................. 50

7.0 REFERENCES .................................................. 51

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LIST OF TABLES

Table No. Description Page No.

1 Garibaldi Waste Rock Data ................................. 12

2 Surface Water Analysis - California Gulch Upstream of Garibaldi Mine Site 15-16

3 Surface Water Analysi s - Garibaldi Portal ..................... 17-18

4 Surface Water Analysi s - Garibaldi Waste Rock Pile (Toe Seep ) ...... 19-20

5 Surface Water Analysi s - California Gulch Downstream of Garibaldi Mine Site ..................................... 21-22

6 Garibaldi Ground-water Analysi s ............................. 23

7 Alternative A - Cost Summary .............................. 36

8 Alternative B - Cost Summary ............................... 39

9 Alternative C - Cost Summary ............................... 42

10 Alternative D - Cost Summary ............................... 44

11 Comparison of Alternatives ................................. 45

12 Summary of Garibaldi Waste Rock EE/CA Alternatives ............ 46

1

2

LIST OF FIGURES

(located following text)

Figure No. Description

General Location Operable Unit 4

LIST OF DRAWING S

(located following text)

Drawing No. Description

1

2

3

4

5

Garibaldi Mine Site Existing Conditions Garibaldi Mine Site Alternative A Garibaldi Mine Site Alternative B Garibaldi Mine Site Alternative C Garibaldi Mine Site Alternative D

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LIST OF ATTACHMENT S

Attachment Description

1 Public Comments and Responses

LIST OF APPENDICES

Appendix Description

ABCDEF

G

State Historic Preservation Offic e Letter HEC-1 Model HELP Model Soi l Loss Calculation s Stabilit y Analysi s ARARs Cost Estimates

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1 .0 EXECUTIV E SUMMAR Y Appendix

1 .1 GENERA L BACKGROUND

Thi s Engineering Evaluation/Cost Analysis (EE/CA) has been performed to identif y a preferred

non-time critical removal action to be implemented for the Garibaldi Mine site located within Upper California Gulch. This area, located approximately three miles southeast of the City of Leadville, is part of Operable Unit 4 (OU-4) of the California Gulch Superfun d Site (Site) in Lake County, Colorado. The general location of the California Gulch Superfun d Site is shown

in Figure 1, General Location.

OU-4 is defined as the area hydrologically drained by California Gulch from immediately

upstream of the Yak Portal to the headwaters of the gulch, as shown in Figure 2, Operable Unit

4. The area covers approximately 2.4 square miles and contains mine waste piles , mill tailing,

and fluvial tailin g material. Approximatel y 150 mine waste rock piles exist in this area (USDC,

1994). Samplin g of surface water, groundwater and stream sediments indicates that mining

activities may have produced acid mine drainage and heavy metal contamination which have

impacted these media. Remedial investigation activities identified fluvial tailin g and waste rock

pile s as areas potentiall y requiring remedial action within OU-4.

The Garibaldi Mine site is located within OU-4 near the headwaters of California Gulch, as

shown in Drawing 1, Garibaldi Mine Site Existing Conditions. Prominent features at the Garibaldi Mine site include a waste rock pile covering an area of approximately 1.6 acres and

a collapsed mine portal (WCC, 1990). A steam engine and other mining remains are located

adjacent to the collapsed portal. Run-on diversion channels have been constructed by the Resurrection/ASARCO Join t Venture around the waste rock pile (WCC, 1990). In addition,

a portion of the portal discharge is currently diverted around the pile. Previous site activities

are further discussed in Section 2.2.

Surface water data indicate that the waste rock pile and/or the Garibaldi Mine portal continue

to contribute to surface water contamination (acidic pH levels; elevated heavy metal loadings)

in Upper California Gulch. Seasonal field observations noted by Resurrection in 1993/94 (SML,

1994; SMI/TerraMatrix, 1994b; SMI/TerraMatrix, 1995) indicate that water discharges from the

toe of the pile. Potential flow pathways through the waste rock pile are further discussed in Section 2.3.3.

1 .2 PROJECT SCOPE AND OBJECTIVES

Thi s EE/CA identifies and evaluates removal action alternatives for the Garibaldi Mine site in OU-4. The project scope includes site characterization (utilizing existing Remedial Investigation

data and additionally collected field data); identification of removal action objectives;

identification and analysis of removal action alternatives; and the selection of the preferred

removal action. The objective of the EE/CA is to identif y a preferred removal action that costeffectively controls or reduces the release of contaminants to the environment and consequently

reduces the potential risk to human health and the environment posed by such releases.

Thi s removal action is part of the overall remedial activities being undertaken in the OU-4 Feasibilit y Study (FS) by Resurrection Mining Company. As such, the removal action

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alternatives evaluated in this EE/CA are considered to represent interim response actions in the

context that remedial alternatives for waste rock and other sources in OU-4 will also be

evaluated in the Feasibility Study. The proposed 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 Record of Decision (ROD) for OU-4 will ultimately determine whether

further remedial actions are required.

1 .3 REMOVA L ACTION ALTERNATIVE S EVALUATE D

Thi s EE/CA discusses efficient , implementable, and cost-effective technologies that appl y to

waste rock removal actions. Guidance for the identification of appropriate technologies is from

the Final Screening Feasibility Study for Remediation Alternatives at the California, Gulch NPL Site, Leadville, Colorado, (SFS) particularly Section 9, Waste Rock (EPA, 1993a) and from the EPAapprovedFzrM/ Engineering Evaluation/Cost Analysis Work Plan for the Garibaldi Mine Site (OU4) (TerraMatrix/SMI, 1994). Guidance for the preparation of this EE/CA is also provided in

the Guidance on Conducting Non-Time-Critical Removal Actions Under the Comprehensive Environmental Response, Compensation, and Liability Act (EPA, 1993b).

T he SFS retained the followin g waste rock alternatives for detailed analysis in the Feasibilit y Study :

• Alternative 1: No Action

• Alternative 2: Institutional Control

• Alternative 3: Containment (Surface Water Control)/Institutional Control

• Alternative 4: Containment (Surface Water Control, Surface Barrier)/ Institutional Controls

• Alternative 5: Containment (Surface Water Control, Source Surface Control)/ Institutional Controls

• Alternative 6: Containment (Surface Water Control, Source Surface Control, Surface Barrier)/Institutional Controls

• Alternative 7: Removal/Transport/Disposal/Institutional Controls

Site-specific application s of these broadly defined alternatives were considered and a limited

number of appropriate removal action alternatives addressing waste rock were retained for

analysis within this EE/CA as further discussed in Section 4.0. The alternatives analyzed

incorporate site-specific application s of the SFS Alternatives. In addition, the alternatives are

consistent with the nature and extent of contamination and the removal action objectives. The

removal action alternatives analyzed in further detail within this EE/CA include:

• Alternative A: Surface Water and Portal Flow Diversion — Thi s alternative

entails the interception and diversion of stream flo w

(including portal flow ) around the waste rock by

reconstruction of existing channels and/or construction of

new channels to prevent run-on to and/or infiltration

through the waste rock. Alternative A is shown on Drawing 2 and corresponds to Alternative 3 as presented in

t he SFS (EPA, 1993a).

• Alternative B: Surface Water, Portal Flow , and Shallow Alluvial Groundwater Diversion — Thi s alternative includes the

interception and diversion of stream flow (including portal

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Alternative C:

flow ) around the waste rock by reconstruction of existing

channels and/or construction of new channels to prevent

run-on to and/or infiltratio n through the waste rock. It

also entails the diversion of shallow alluvial groundwater

flow around the waste rock by construction of groundwater

interceptor trenches. Alternative B is shown on Drawing

3 and also corresponds to Alternative 3 as presented in the S FS (EPA, 1993a).

Surface Water, Portal Flow, and Shallow Alluvial Groundwater Diversion/Regrading/Simple Cover — Thi s

alternative includes the interception and diversion of stream

flow (including portal flow ) around the waste rock by

reconstruction of existing channels and/or construction of

new channels to prevent run-on to and/or infiltratio n

through the waste rock; diversion of shallow alluvial

groundwater flow around the waste rock by construction of

groundwater interceptor trenches; and regrading of the

waste rock pile and construction of a simple cover to

minimize infiltratio n through the waste rock pile and

expedite non-erosive runof f from the pile surface. The

simple cover would be designed as both a source surface

control and surface barrier. Alternative C is shown in Drawing 4 and corresponds to Alternative 5 as presented in

t he SFS (EPA, 1993a).

Waste Rock Removal — Thi s alternative entails the removal

of the waste rock from the site and transport to the Oregon Gulch Tailin g Impoundment for disposal . It also includes

reestablishment of the original drainage channel. Alternative D, shown on Drawing 5, corresponds to Alternative 7 as presented in the SFS (EPA, 1993a).

Institutional controls (Alternative 2 in the SFS), including posted warnings, information and

education programs, and/or other controls would also be incorporated as approved by the EPA,

within the removal action alternatives evaluated.

The criteria utilized in the analysis of the four removal action alternatives are defined in the Guidance on Conducting Non-Time-Critical Removal Actions Under the Comprehensive Environmental Response, Compensation,, and Liability Act (CERCLA) (EPA, 1993b), and include

effectiveness , implementability , and cost. These EPA criteria are utilized as screening criteria

to aid in the selection of the appropriate removal action for the Garibaldi Mine site. In

addition, the Work Area Management Plan (WAMP) (USDC, 1994) performance criteria of

erosion stabilit y and flow capacity and stability are utilized in evaluating the effectivenes s of the

removal action alternatives in meeting the removal action objectives (RAOs). RAOs are further

discussed in Section 3.2.

After detailed evaluation of the individual removal action alternatives (Section 4.0), a

comparative analysis of these alternatives is presented (Section 5.0) which identifies the

Alternative D:

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advantages and disadvantages of each alternative relative to one another considering the EPA

criteria of effectiveness , implementability , and cost.

1 .4 RECOMMENDE D REMOVAL ACTION ALTERNATIV E

Based on the individual analysis of alternatives presented in Section 4.0 and the comparative

analysis presented in Section 5.0, Alternative B (Surface Water, Portal Flow, and Shallo w Alluvial Groundwater Diversion) is recommended for implementation. Alternative B would

meet the RAOs described in Section 3.2.

Alternative B entails the interception and diversion of stream flow (includin g portal flow )

around the waste rock by the reconstruction of existing channels and/or the construction of

new channels to prevent run-on to and/or infiltratio n through the waste rock. It also entails

the diversion of shallow alluvial groundwater flow around the waste rock by construction of

groundwater interceptor trenches.

Best management practices (BMPs), as described under Alternative A in Section 4.3.1.2 would

be utilized during all construction activities at the site.

1 .5 REPORT ORGANIZATION

Thi s EE/CA is organized into seven Section s as follows:

• Section 1.0 — Executive Summary: Thi s section provides a general overview of

the site, project scope and objectives, removal action alternatives evaluated, the

evaluation performed, the recommended removal action alternative, and a general

overview of the contents of the EE/CA.

• Section 2.0 — Site Characterization: Thi s section provides a discussion of the site

description and background; previous removal actions; source, nature, and extent

of contamination; analytical data; and the streamlined risk evaluation.

• Section 3.0 — Identificatio n of Removal Action Objectives: Thi s section presents

statutory limit s on removal actions, determination of removal action scope, and

the removal action schedule.

• Section 4.0 — Identification and Analysi s of Removal Action Alternatives: Removal action alternatives are identified and evaluated based upon effectiveness,

implementability , and cost.

• ' Section 5.0 — Comparative Analysis of Removal Action Alternatives: In this

section, a comparative analysis is presented which identifies the advantages and

disadvantages of each alternative relative to one another considering the criteria

of effectiveness, implementability , and cost.

• Section 6.0 — Recommended Removal Action Alternative: The removal action

that best satisfies the evaluation criteria is recommended and described in this

section.

• Section 7.0 — Thi s section list s references cited in the text.

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Supportin g data is presented in several appendices , as outlined below:

Appendix A — State Historic Preservation Offic e Letter Appendix B — HEC-1 Model Appendix C - HELP Model Appendix D — Soi l Loss Calculation s Appendix E — Stabilit y Analysi s Appendix F — ARARs Appendix G — Cost Estimates

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2 .0 SIT E CHARACTERIZATION

2 .1 SIT E DESCRIPTION AN D BACKGROUN D

2.1.1 Site Identificatio n and Background

Thi s EE/CA has been prepared to evaluate potential removal action alternatives and to select

a preferred alternative for the remediation of waste rock at the Garibaldi Mine site located

within Upper California Gulch. Thi s area, located approximately three miles southeast of the City of Leadville, is part of Operable Unit 4 (OU-4) of the California Gulch Superfun d Site in Lake County, Colorado. Lake County is approximately 100 miles southwest of the City of Denver. The general location of the California Gulch Superfun d Site is shown in Figure 1, General Location.

The California Gulch/Leadville area has been an active mining area since the 1850s. Associated

with the extensive underground mining activities are the remaining surface features such as mine

workings, waste rock, and tailin g ponds. In addition , mine drainage tunnels were constructed

to dewater the mine workings.

OU-4 is defined as the area hydrologically drained by California Gulch from immediately

upstream of the Yak Portal to the headwaters of the gulch, as shown in Figure 2, Operable Unit

4. The area covers approximately 2.4 square miles and contains mine waste piles, mill tailing,

and fluvial tailin g material. Approximatel y 150 mine waste rock piles exist in this area (USDC,

1994). Samplin g of surface water, groundwater, and stream sediments indicate that mining

activities may have contributed acid mine drainage and heavy metal contamination to these

media. Remedial investigation activities identified fluvial tailin g and waste rock piles as areas

potentiall y requiring remedial action within OU-4. The subject of this EE/CA is the waste rock

located at the Garibaldi Mine site in OU-4. The Garibaldi Mine site is located within OU-4

near the headwaters of California Gulch, as shown in Figure 2, Operable Unit 4, and detailed

in Drawing 1, Garibaldi Mine Site Existing Conditions.

2.1.2 Regulatory Framework

Thi s EE/CA has been undertaken in accordance with the Work Area, Management Plan (WAMP)

for Resurrection Mining Company included as an appendix to the Consent Decree in settlement

of Civil Action No. 83-C-2388, United States District Court for the District of Colorado

(USDC, 1994), and in accordance with guidance provided in 40 Code of Federal Regulations

(CFR) 300. In addition, guidance provided within the Guidance on Conducting Non-Time- Critical Removal Actions Under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) (EPA, 1993b) has been incorporated into this EE/CA study.

2.1.3 Facility Type and Operational Status

The Garibaldi Mine site is located within OU-4 near the headwaters of California Gulch

approximately 150 feet west of the Western Faul t between Breece Hill and Green Mountain

(WCC, 1990). The Garibaldi Mine site is shown in Drawing 1, Garibaldi Mine Site Existing Conditions. As a component of Garibaldi Mine, the Garibaldi tunnel extends 2400 feet

northeast to the workings of the Sunday No. 2 Mine on the west slope of Ball Mountain, and

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was built to drain these workings (Emmons et al., 1929). Prominent features at the Garibaldi Mine site include a waste rock pile covering an area of approximatel y 1.6 acres and a collapsed

mine portal (WCC, 1990). A steam engine and other mining remains are located adjacent to the

collapsed portal . " Run-on diversion channels have been constructed by the Resurrection/ASARCO Join t Venture around the waste rock pile. In addition, a portion of the

portal discharge is currently diverted around the pile (WCC, 1990).

Surface water data indicates that the waste rock pile continues to contribute to surface water

contamination (acidic pH levels; elevated heavy metal loadings) in Upper California Gulch. Field observations by Resurrection indicate that water discharges from the toe of the pile.

2.1.4 Topograph y

T he Garibaldi Mine site is located near the headwaters of California Gulch in a small tributary

drainage, as shown in Figure 2 and Drawing 1. The site is at an elevation of approximately

11,175 feet above mean sea level (AMSL) at the portal and 11,120 feet AMSL at the toe of the

waste rock pile. The channel downstream of the Garibaldi Mine site is a small, V-shaped valley

with water flowin g in a southwesterly direction. Upper California Gulch crosses Lake County Road 2, approximatel y one third of a mile downstream of the Garibaldi Mine site.

2.1.5 Pedolog y and Geolog y

The Troutville and Bross series, consisting of deep, well drained soils on mountain slopes, are

the predominant soil types in the vicinity of the Garibaldi Mine site. Deep, sandy loam, within

the Tomichi series, also occurs in drainage channels upgradient of the Garibaldi Mine site.

T he geology in Upper California Gulch consists of shallow colluvium over Precambrian granitic

and metamorphic rocks and Paleozoic sedimentary rocks. The Pendry Fault , a local prominent

faul t marking the boundary between Lower and Upper California Gulch, has a north 20 degrees

east trend (Emmons et al., 1927). The Garibaldi Mine site is located upstream of the Pendry Fault . California Gulch was not glaciated and upstream of the Pendry Faul t the unconsolidated

material can generally be characterized as relatively thin deposit s of alluvium, talus, and

colluvium. Extensive areas of the Upper California Gulch drainage, including most of Iron and Breece Hills, are covered with a thin layer of talus "wash" which consists of fragments of the

underlying bedrock (WWL , 1990).

2.1.6 Hydrolog y

OU-4 includes the Upper California Gulch drainage basin which is the area hydrologically

drained by California Gulch from immediately upstream of the Yak Tunnel Portal to the

headwaters of the gulch. Approximatel y 2.4 square miles are drained by Upper California Gulch.

The Garibaldi Mine site is located in the Upper California Gulch sub-basin which covers an area

of approximately 211 acres. The site is located at the confluence of two headwater sub-basins

of Upper California Gulch. The northern headwater basin covers an area of approximately 134

acres, draining a portion of the southern flan k of Breece Hill and the northwestern flan k of Ball Mountain. The channel outlet draining the northern headwater sub-basin lies slightly to the

northwest of the mine portal. The southern headwater basin covers approximately 77 acres,

draining the western portion of Ball Mountain and the northerly portion of the topographic

divide that separates Upper California Gulch from Upper Iowa Gulch. The channel outlet

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draining the southern headwater sub-basin lies slightly southeast of the mine portal . Surface

water flo w in this section of Upper California Gulch is ephemeral, generally resulting from

snowmelt or summer thunderstorms.

Surface water samplin g and flow measurement have been conducted in the vicinity of the Garibaldi Mine site. Section 2.3.3 discusses water quality data for samples collected upstream,

downstream, at the portal , and at the toe of the Garibaldi Mine site. The water is generally

characterized by low pH with elevated levels of dissolved metals.

Groundwater in the Leadville area occurs in both bedrock and alluvial stratigraphy. The

geologic structure of the region varies in relation to the Pendry Fault . The Pendry Faul t lies

along the eastern edge of Leadville and intersects California Gulch jus t below the Yak Tunnel Treatment Plant surge pond (WWL, 1990). Downstream of the Pendry Faul t deep terrace gravel

a nd lake bed unconsolidated deposit s cover the bedrock. Upgradien t of the Pendry Fault , California Gulch was not glaciated (Tweto, 1970), and unconsolidated material can generally be

characterized as relatively thin deposit s .of alluvium, talus, and colluvium over Precambrium

granitic and metamorphic rocks and Palozoic sedimentary rocks (Tweto, 1970; WWL , 1990; WCC, 1993a). Alluvium occurring in the Upper California Gulch as gravel deposit s is limited

to the bed of California Gulch (Emmons, et al., 1927). Drillin g logs suggest that in OU-4 the

thickness of the overlying unconsolidated alluvium/colluvium ranges from 2 to 43 feet (EPA,

1987a; WCC, 1993a).

T he various types of rock that comprise the bedrock are considered to form a single aquifer

system because they are hydraulically connected through mine workings and the extensive

faultin g and fracturing (Turk and Taylor, 1979). A complex system of major and minor fault s

causes significant displacement and fracturing of the bedrock (Emmons, et al., 1927). Flo w

within the bedrock is primarily facilitated by secondary porosity and mine workings in the area

(WCC, 1993a). Secondary porosity consists of the permeable and highly fractured zones

adjacent to the major fault s and the numerous interconnected minor fault s and fractures within

t he faul t blocks. The groundwater in Upper California Gulch occurs primarily in bedrock

aquifers (EPA, 1987), apparently existing under unconsolidated conditions, however,

irregularities in the fracture dominated flo w system may cause partiall y confined or perched

conditions locally (WCC, 1993a). The surficial alluvium/colluvium deposit s appear to be locally

saturated with groundwater (WCC, 1993a; SMI/TerraMatrix, 1995a). Regionally, recharge of

alluvial and bedrock aquifers results from infiltratio n of precipitation (rainfal l and snowmelt) and

surface water.

S ix background bedrock groundwater wells and three bedrock monitoring wells were installed

within the California Gulch Site during the Remedial Investigation (RI) process (WCC, 1993a). Four of the background bedrock groundwater wells are located within OU-4. Additionally , two

shallow alluvial monitoring wells were installed within OU-4 in 1989, only one of which is

currently operational (WWL, 1990). During the fall of 1994, three additional groundwater

monitoring wells were constructed, two which are adjacent to the Garibaldi Mine site and one

within the Agwalt Mine site (SMI/TerraMatrix, 1995a).

The monitoring wells drilled as part of the RI were installed to depths of 291 to 1,227 feet. Depth to groundwater in the bedrock aquifer range from about 30 feet to roughly 670 feet

below ground surface. At the operational alluvial groundwater well upgradient of the Yak Tunnel Portal, a golden brown dolomite bedrock was encountered at a depth of 43 feet (EPA,

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1987a), and the depth to groundwater ranges from approximately 5.9 to 15.8 below ground

surface (WWL, 1990; SMI, 1994; SMI/TerraMatrix, 1994b; SMI/TerraMatrix, 1995).

Depth to bedrock in the two groundwater wells installed at the Garibaldi site ranged from

approximately 10 to 11 feet, respectively (SMI/TerraMatrix, 1995b). Localized groundwater was

encountered in one of the wells during construction at approximately 9.5 feet below ground

surface.

2.1.7 Surroundin g Land Use and Populatio n

T he California Gulch Site is located in the upper Arkansas River watershed, with elevations

ranging from approximately 9,570 feet AMSL to 12,250 feet AMSL. The site encompasses

approximately 16.5 square miles and includes the towns of Leadville and Stringtown and extends

to the confluence of California Gulch and the Arkansas River. The site is located in a highly mineralized area of the Rocky Mountains, and mining, mineral processing and smelting activities

have produced gold, silver, lead and zinc for more than 130 years. A large portion of this site

has been affected by these activities.

Lake County is relatively small (380 square miles) and predominately rural county with a 1990

population of 6,007 (U.S. Department of Commerce, 1990). Approximately half of the

populatio n reside within the City of Leadville. The populatio n of Lake County has fluctuated

with the mining industry. The populatio n increased to approximately 9,000 between 1960 and

1981 and then declined throughout the 1980s. Approximatel y two-thirds of the land in Lake County is federall y owned, and is part of San Isabel National Forest or is managed by the Bureau of Land Management. Land surrounding and within California Gulch is predominately

dedicated to mining, commercial, and residential uses.

An unimproved dirt road runs from the hairpin turn on Lake County Road 2 along California Gulch to the Garibaldi Mine site. No other improvements exist at the Garibaldi site.

2.1.8 Sensitive Ecosystems

Previous investigations reveal that the occurrence of threatened, endangered or sensitive species

in the terrestrial ecosystem is unlikely (WCC, 1993b). However, erosion of tailin g material and

contaminated stream sediment contribute heavy metal loading to California Gulch and the Arkansas River. These releases potentiall y affect the aquatic ecosystem.

2.1.9 Climate

The climate of Lake County is relatively dry, but is otherwise typical of most alpine regions in

the southern Rocky Mountains. The average annual maximum temperature in the Leadville area

is 50.5 degrees Fahrenheit and the average annual minimum temperature is 21.9 degrees Fahrenheit, with an annual mean temperature of 37.3 degrees Fahrenheit.

Precipitation occurs throughout the year with the most significant precipitation occurring as rain

in the summer months of Jul y and August. Precipitation varies throughout Lake County in

relation to the elevation. The south-central portion of the county at an elevation near 9,000 feet AMSL, receives about 10 inches of precipitation annually. At higher elevations precipitation

can reach 40 inches per year. The mean annual snowfall ranges from 134 inches at the lower

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elevations to 271 inches at the higher elevations. The wind is predominantly from the

northwest, with speeds typicall y from 0 to 30 mph (WCC, 1993a).

2.1.10 Historic and Cultural Resources

A cultural resource survey was conducted by Goodson and Associates, Inc., (Martorano, 1990)

prior to implementation of site improvements by the Resurrection/ASARCO Join t Venture in

1990. The objective of the survey was to identify , record, and provide evaluations of the

historic and prehistoric resources which could have been affected by the site improvements. The

primary tasks included a literature and records search, and intensive pedestrian survey of areas

potentiall y impacted, data analysis, and preparation of a report. An assessment of effect is

required for all resources determined eligible for or listed in the National Register of Historic Places (NRHP), and located within the Area of Potential Effec t (APE).

T he 1990 cultural resource investigations at the Garibaldi Mine Site (OU4) resulted in the

recordation and documentation of the Garibaldi Mine as site 5LK805. Thi s resource, 5LK805,

w as officiall y determined not eligible for listin g in the NRHP by the State Historic Preservation Offic e (SHPO), on August 31, 1990 (see Appendix A). Under Section 106 of the National Historic Preservation act of 1966 (as amended), no assessment of effect is required for resources

determined not eligible for the NRHP. No further cultural resource investigations are required

prior to implementation of ground-disturbing activities. Such actions are considered to have no

effect on historic properties , provided the Area of Potential Effec t (APE) does not extend

beyond the area previously surveyed. Additional cultural resource investigations would be

required for any proposed actions outside of the areas previously surveyed.

2 .2 PREVIOU S REMOVAL ACTIONS

In 1990/1991, the Resurrection/ASARCO Join t Venture constructed run-on diversion channels

around the waste rock pile and a portal discharge diversion (WCC, 1990). The intent of the site

improvements was to reduce the volume and mobility of contaminated material by minimizing

the water infiltratin g into and out of the mine workings and waste rock pile.

The main improvement for this site was the regrading of the dirt road above the Garibaldi

tunnel portal. The road was reconstructed to convey stormwater on the uphil l part (northern

side) of the road instead of allowing the water to flow across the road and downhill into the

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

The existing profile of the road did not change and remained relatively flat with a small ditch

on the uphil l side. The road was regraded to be uniformly slopin g at approximately 3 to 5%

down toward the uphil l side. Approximately two feet away from the center of the uphil l ditch,

the downward slope of the road (along the cross-sectional dimension at the beginning of the

ditch) was increased. The cut slope of the existing hill north and west of the road was

maintained or flattened to approximately 1:2 (1 horizontal to 2 vertical). The bottom of the

ditch was constructed to be at least one foot wide and the top at least 3 feet wide. The ditch

was terminated downhill from the waste pile as indicated on Drawing 1. Flow is diverted into

a culvert which carries it under the road and discharges it down the hill below the base of the

waste pile. The outfal l area was protected from erosion with riprap.

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To divert runof f from the hillside east and southeast of the mine waste, a ditch was construaed

along the south side of the pile, near the southwesterly end of the waste pile and extended to

t he portal of the Garibaldi tunnel. Riprap, geotextile, grass, and/or straw were used to protect

t he ditch from erosion. The flow from Garibaldi tunnel is diverted into the new ditch. The

flow is then routed under the road by culvert to the ditch running parallel to the road. The size

of this ditch is the same as described above for the ditch adjacent to the road.

These site improvements were expected to reduce the amount of run-on to the waste pile and

thus reduce infiltratio n into the waste pile in the mine workings area by diverting run-on

around this area. It was anticipated that the quantity of poor quality water seeping from the

mine workings into California Gulch would be reduced. Recent surface water data indicates,

however, that the Garibaldi waste rock and mine portal continue to contribute to surface water

contamination (acidic pH levels; elevated heavy metal loadings) in Upper California Gulch.

2 .3 SOURCE , NATURE , AND EXTENT OF CONTAMINATION

2.3.1 Identificatio n of Sources of Hazardous or Contaminatin g Substances

Thi s EE/CA addresses mitigation of the Garibaldi Mine site. The major source of

contamination at this site is the waste rock pile. Runof f from spring snowmelt and storm

events, and flow from the Garibaldi portal have leached metal contaminants from the waste

rock, and consequently increased the metal loading to Upper California Gulch. Laboratory

analyses of the surface waste rock material collected at the Garibaldi Mine site (Fall 1994)

confirms that the waste rock has the potential to generate acid rock drainage and release metals. Thi s is further discussed in the followin g section.

2.3.2 Characteristics of Source

Field reconnaissance of the waste rock piles within Upper California Gulch was conducted in August 1993 (SMI/TerraMatrix, 1994a) and September 1994 (TerraMatrix/SMI 1995). The

investigations indicated that the Garibaldi waste rock pile covers a surface area of approximately

1.6 acres, has an average height of approximately 35 feet and contains a volume of approximately

27,900 cubic yards of material. The face angle of the waste rock pile is approximately 32-35

degrees. The waste rock is primarily coarse to fine grained material and no vegetation is present

on the pile. The waste rock pile is within the Upper California Gulch drainage and includes

the Xmas, No Name, Ohio Bonanza, and Lady Crawford claims.

Laboratory analysis of a composite sample collected from the Garibaldi waste rock pile in fall

1994 confirmed that surface material on the mine waste pile has the potential to generate acid

and leach metals. The followin g analyses were performed on the sample:

*

• Acid-Base Accounting (ABA) test

• Synthetic Precipitation Leaching Procedure (EPA Method 1312)

• Total Metal s Analysis

• Grain size

Results of these analyses are presented in Table 1, Garibaldi Mine Waste Geochemical Data, and

are discussed below.

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TABLE 1 GARIBALD I WAST E ROCK DATA (Sample Site UCG-1 21 ) October 1994

A BA Analysi s

Sulfur, S04 (%) Sulfur, Pyr. & Org.(%) Sulfur, Total {% ) A G P (T/KT ) Neutralizin g Potential (% CaC03) A N P (T/KT ) A B P (T/KT )

1312 Analysi s

Arsenic Cadmium Calcium Iro n Lead Magnesium Mercury Potassium Sodium Zin c

pHAlkalinit y T D S

Chloride Sulfat e

Total Metal s

Arsenic Cadmium Lead Zin c

Texture

San d (%) Sil t (%) Cla y (%) Texture Classificatio n

0.84

1.59

2.43

75.9

0.1

0

-75.9

Concentration (mg/L )

0.0015

0.034

19.11

10.3

4.59

5.05

< 0.0002

1.78

2.58

6.24

2.9

2

254

1

345

Concentration (mg/kg )

1 15

0.61

3,570

382

60

19

21 S CL

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T he ABA test is a commonly-used method to evaluate the potential of a material to generate

acid. The test involves measuring and comparing a sample's maximum acid production potential

( AP or AGP) with its maximum neutralization potential (NP or ANP). The differenc e between AP and NP is referred to as the Acid Base Potential (ABP) or Net Neutralizatio n Potential

(NNP). As stated in the draft technical document Acid Mine Drainage Prediction, (EPA, 1994):

If the difference between (ANP) and (AGP) is negative then the potential exists

for the waste to form acid. If it is positive then there may be lower risk. Prediction of the acid potential when the (ABP) is between -20 and 20 (T CaCO3/KT ) is more difficul t (EPA, 1994).

T he ABP of the sample collected from Garibaldi was -75.9 (T CaCO3/KT) , indicating that

surface material on the mine waste pile has a high potential to form acid.

To evaluate the potential of this material to leach metals when contacted with precipitation , the

sample was analyzed by EPA Method 1312. Thi s test involves mixing a sample with a synthetic

rainwater solution and analyzing the leachate that is generated for metals and other

contaminants of concern. Although the metal concentrations measured in the leachate cannot

be directly compared to the concentrations that would occur in site runof f due. to differences

in sample dilution , the results do give an indication of which constituents may be elevated.

T he leachate from the surface material collected from Garibaldi was strongly acidic (pH 2.9) and

contained elevated concentrations of cadmium (0.034 mg/1), iron (10.3 mg/1), lead (4.59 mg/1),

sulfate (345 mg/1) and zinc (6.24 mg/1). With the exception of lead, these leachate characteristics

are comparable to the quality of seep samples collected at the toe of the mine waste pile and

surface water samples collected in California Gulch downstream of Garibaldi.

Lead concentrations in the seep and downgradient surface water samples were significantly lower

(0.002 to 0.029 mg/1) than in the leachate sample (4.59 mg/1), suggesting that if this metal is

leached from the surface material at the site, it is significantl y attenuated within and/or

immediately downgradient of the mine waste pile. Conversely, the concentration of arsenic in

the leachate sample was relatively low (0.0015 mg/1) compared to concentrations observed in the

toe seep and downgradient surface water samples (0.010 to 0.084 mg/1). Thi s may suggest a

source of arsenic occurs within, or immediately downgradient of, the Garibaldi mine waste pile.

In addition to ABA and leaching tests, the composite sample collected from Garibaldi was

analyzed for the total concentration of four metals (arsenic, cadmium, lead, and zinc). Total

metal analyses were performed to verify the source of some of the metals measured in the

sample leachate and to assess potential air and water loading effect s should surface material at

the site be disturbed during reclamation activities. The surface material at Garibaldi contained

115 mg/kg total arsenic, 0.61 mg/kg total cadmium, 3,570 mg/kg total lead, and 382 mg/kg total

zinc.

Finally , for use in potential reclamation and geotechnical evaluations, a grain size analysis was

performed on the surface material at Garibaldi. The material was foun d to contain the

followin g grain size fractions:

• Sand (60%)

• Silt (19%) • Clay (21%)

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Note that these percentages reflect the grain size distribution of the finer material exposed on

the surface of the pile that was sampled for geochemical analysis. Coarser material such as

gravels, cobbles, and boulders were not used to prepare the composite sample.

2.3.3 Physical and Chemical Attributes of Contamination

Surface water samplin g and analyses have been conducted at several monitoring locations in the

vicinity of the Garibaldi Mine site (WWL, 1990 and SMI, 1994; SMI/TerraMatrix , 1994b; SMI/TerraMatrix, 1995a). Monitoring activities were conducted at the followin g sites:

California Gulch to the southeast and upstream of the Garibaldi Mine site (CG-17) California Gulch to the northwest and upstream of the Garibaldi Mine site (CG-1F) Garibaldi Portal (GP-1) Garibaldi waste rock pile toe seep (GM-1) California Gulch directly downstream of the Garibaldi Mine site (CG-16) California Gulch downstream of the Garibaldi Mine site at County Road 2 (CG-1G)

In addition, groundwater sampling and analyses have been conducted at a shallow alluvial well

located in the east drainage above the Garibaldi Mine site. The well (GMW1W) was installed

in October 1994 to investigate the presence of groundwater at the site.

Monitoring locations are presented in Drawing 1.

Surface water data are presented in Table 2, Surface Water Analysis - California Gulch Upstream

of Garibaldi Mine Site; Table 3, Surface Water Analysis - Garibaldi Portal; Table 4, Surface Water Analysis - Garibaldi Waste Rock Pile (Toe Seep) ; and Table 5, Surface Water Analysis - California Gulch Downstream of Garibaldi Mine Site. Groundwater data are presented in Table

6, Garibaldi Groundwater Analysis.

Surface and groundwater quality samples were collected at 3 monitoring stations located

upgradient of the Garibaldi Mine site; CG-17, CG-1F, and GMW1W. Analysi s of the samples

indicated the followin g concentration ranges for selected constituents:

Alkalinit y - 7 to 76 mg/1 (as CaCO3); Sulfate (D) - 13 to 103 mg/1; TDS - 32 to 238 mg/1;

pH (field) - 6.34 to 6.75; Arsenic (D) - < 0.001 to < 0.005 mg/1; Cadmium (D) - < 0.005 to 0.002 mg/1 Chromium (D) - < 0.005 mg/1; Copper (D) - < 0.005 to <0.01 mg/1; Iron (D) - <0.01 to 0.07 mg/1; Lead (D) - < 0.001 to < 0.005 mg/1; Manganese (D) - < 0.005 to 0.05 mg/1; Nickel (D)- <0.01 mg/1; Selenium (D) - < 0.005 mg/1; Silver (D) - < 0.0002 to < 0.005 mg/1; and, Zinc (D) - 0.08 to 0.37 mg/1.

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TABLE 2 SURFAC E WATE R ANALYSI S - CALIFORNIA GULCH UPSTREAM O F GARIBALD I MIN E SIT E

Location

Date

Source

Flo w (cfs ) Cd-D

Cd-T

Cu-D

Cu-T

Pb-D

Pb-T

Zn-D

Zn-T

AI-D

AI-T

As-D

As-T

Ba-D

Ba-T

Bi-D

Bi-T

Cr-D

Cr-T

Fe-D

Fe-T

Mn-D

Mn-T

Ni-D

Ni-T

Se-D

Se-T

Ag-D

Ag-T

Sr-D

Sr-T

Ca-D

Ca-T

Mg-D

Mg-T

Na-D

Na-T

K -D

CG-17

06/09/89

W WL

0.0053

<0.005

<0.005

<0.005

<0.005

<0.005

<0.005

0.18

0.17

<0.1

<0.1

< 0.005

< 0.005

0.05

<0.05

<0.5

<0.5

<0.005

<0.005

<0.01

0.03

<0.005

<0.005

<0.01

<0.01

<0.005

< 0.005

< 0.005

<0.005

0.02

0.02

8.4

7.6

1.4

1.3

0.4

0.4

0.7

GMG-1

06/09/89

W WL

0.0043

< 0.005

<0.005

< 0.005

< 0.005

< 0.005

< 0.005

0.031

0.045

<0.1

0.2

< 0.005

< 0.005

0.09

^_ 0.08

<0.5

<0.5

< 0.005

<0.005

0.04

0.26

< 0.005

0.009

<0.01

<0.01

< 0.005

< 0.005

< 0.005

< 0.005

0.02

0.02

6

5.4

0.66

0.63

0.7

0.6

0.6

CG-17 AN D

GMG-1

10/26/89

W WL

DRY

CG-1F

05/26/94

S M I

0.45

0.0006

0.0006

<0.01

<0.01

<0.001

0.003 u(uj )

0.08

0.09 u

0.19

0.19

<0.001

<0.001

na

na

na

na

na

na

0.07

0.08 u

0.04

0.04

na

na

na

na

<0.0005

< 0.0005 u j

na

na

5.4

na

0.8

0.8

0.6

na

na

CG-1F

10/05/94

S M I

DRY

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July 27, 1995 FINAL * EE/CA Garibaldi Mine Site * 16

TABL E 2 (cont'd ) SURFAC E WATE R ANALYSI S - CALIFORNIA GULCH UPSTREAM O F GARIBALD I MIN E SIT E

Location

Date

Source

K -T

Si-D

Si-T

CI-D

CI-T

F -D

F -T

CN-T

Acidit y S 04-T (filt ) S 04-T (unfilt ) Alkalinity- T (filt ) Alkalinity-T (unfilt ) Carbonate-D

Carbonate-T

Bicarbonate-D

Bicarbonate-T

pH (lab )

pH (lab-filt )

pH (lab-unfilt ) Spec . Cond. (lab )

pH (field ) Spe c Cond (field) T D S

T S S

Temp (C° )

CG-17

06/09/89

W WL

0.6

5.3

5.0

<3

<3

<0.5

<0.5

< 0.005

0.04

16

20

na

7

<5

<5

9

9

6.9

ns

ns

76

6.34

66

56

<5

2.2

GMG-1

06/09/89

W WL

0.5

4

3.3

<3

<3

<0.5

<0.5

<0.005

0.04

13

14

na

10

<5

<5

12

12

6.9

ns

ns

47

6.65

44

40

<5

4.6

CG-17 AN D

GMG-1

10/26/89

W WL

CG-1F

05/26/94

S M I

na

na

na

na

na

na

na

na

na

15

12

13

8

na

na

na

na

ns

6.82 J

6.85 j

na

6.75

503

32

na

4.3

CG-1F

10/05/94

S MI

Concentration in mg/l ; discharge in cfs; pH in standard units; specifi c conductance in ^/mhos/cm;

acidit y in meq/l .

T = Total na = not analyzed D = Dissolved u = not detected

ns = not specified j = data estimated

CG-17 = California Gulch to SE above Garibaldi CMG-1 = California Gulch to NE above Garibaldi (site known as CG-1F after 1993 )

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July 27, 1995 FINAL * EE/CA Garibaldi Mine Site 4 17

TABLE 3 SURFAC E WATE R ANALYSI S - GARIBALD I PORTA L

Location

Date Source

Flo w (cfs ) Cd-D

Cd-T

Cu-D

Cu-T

Pb-D

Pb-T

Zn-D

Zn-T

AI-D

AI-T

Sb-D

Sb-T

As-D

As-T Ba-D Ba-T Be-D Be-T Bi-D Bi-T

Cr-D

Cr-T Fe-D

Fe-T

Mn-D

Mn-T Hg-D Hg-T

Mo-D

Mo-T

Ni-D

Ni-T

Se-D

Se-T

Ag-D

Ag-T

Sr-D

Sr-T

Ti-D

Ti-T

Ca-D

Ca-T

Mg-D

Mg-T

GM-1 [WWL ]

06/09/89

W WL

0.0128

0.011

0.011

0.019

0.019

< 0.005

< 0.005

1.7

1.6

0.3

0.2

na

na

<0.005

<0.005

<0.05

<0.05

na

na

<0.5

<0.5

< 0.005

< 0.005

<0.01

0.03

1.5

1.4

na

na

na

na

<0.01

0.01

<0.005

<0.005

<0.005

<0.005

0.05

0.05

na

na

20

19

3.8

3.6

GM-1 [WWL ]

10/26/89

W WL

0.0011

0.009

0.009

0.018

0.028

0.009

0.014

1.2

1.2

0.3

0.4

na

na

<0.005

< 0.005

<0.05

<0.05

na

na

na

na

<0.005

<0.005

<0.01

0.25

1.8

1.7

na

na

na

na

<0.01

<0.01

< 0.005

< 0.005

<0.005

< 0.0.05

0.04

0.05

na

na

na

21

na

4.4

TP-2

10/16/9 1 W CC

0.0025

0.0116 u

0.0102 b

0.05 b

0.05 b

0.0088

0.0103

1.39

1.05n

0.334

0.385

0.12 b

0.12 u

0.02 u

0.02 u

0.4 be

0.4 b

0.01 u

0.01 u

na

na

0.02 u

0.02 u

0.2 u

0.2 b

1.67

1.79

0.0002 u

0.0002 u

0.04 u

0.04 u

0.08 b

0.08 b

0.01 u

,

 na

0.02 u

0.02 u

na

na

0.01 u

0.01 b

na

23

na

5

TP-2

09/15/92

W CC

0.0033

0.024

0.0257

0.0882

0.0778

0.0068

0.0089

3.59

2.99 e

0.431

0.467

0.06 b

0.12 u

0.01 u

0.02 b

0.2 b

0.4 b

0.005 u

0.005 u

na

na

0.01 u

0.02 u

0.1 u

0.1 b

2.06

1.88

0.0002.U

0.0003

0.02 u

0.04 u

0.04 b

0.08 b

0.005 u

0.01 un

0.01 un

0.02 u

na

na

0.01 b

0.01 b

na

26

na

5 u

GP-1

05/26/94

S M I

0.08

0.012

0.012

0.06 j

0.05 j

0.009

0.016

1.6

1.5

0.45 j

0.38 j

na

na

<0.001

0.001

na

na

na

na

na

na

na

na

0.08

0.16 u

0.9

0.87

na

na

na

na

na

na

na

na

<0.005

<0.005 uj

na

na

na

na

13.7

na

2.6

2.5

GP-1

10/05/94

S M I

0.001

0.0033 j

0.018 j

0.05 j

0.04 j

0.008

0.037

2.05

1.88

0.55

1.48

na

na

<0.001 uj

0.004 u

na

na

na

na

na

na

na

na

0.02 u

1.54

1.83

1.84

na

na

na

na

na

na

na

na

< 0.0005

0.0012

na

na

na

na

22

na

5 j

4 j

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TABLE 3 (conf d) SURFAC E WATE R ANALYSI S - GARIBALD I PORTA L

Location Date Source Na-D Na-T

K -D

K -T

Si-D

Si-T

CI-D

CI-T

F -D

F -T

CN- D

CN-T

Acidit y Alkalinity- T (filt ) Alkalinity-T (unfilt ) Carbonate-D

Carbonate-T Bicarbonate-D Bicarbonate-T

NO3/NO 2 S 04

 (unfilt ) S 0 4

 (filt ) P04-T

pH (lab)

pH (lab-filt )

pH (lab-unfilt ) Spec . Cond. (lab )

pH (field ) Spe c Cond (field ) T S S T D S

Tem p (°C )

GM-1 [WWL ]

06/09/89

W WL

0.7

0.6

1.2

1.0

4.4

3.8

<3

<3

<0.5

<0.5

na

<0.005

0.26

na

<5

<5

<5

<5

<5

na

70

67

na

4.7

ns

ns

200

4.57

198

<5

130

2.9

GM-1 [WWL ]

10/26/89

W WL

na

0.8

na

1.2

na

3.3

na

<3

na

<0.5

na

<0.005

0.22

na

<5

na

<5

na

<5

na

86

na

na

4.4

ns

ns

190

4.52

260

6

130

3.1

TP-2

10/16/91 W CC

na

5 u

na

5 u

na

9

1 u

na

0.1 u

na

na

0.01 u

na

na

2

na

na

na

na

0.07

88

na

0.01 u

4.7

ns

ns

229

4.44

202

2

2 u

124

3.9

TP-2

09/15/92

W CC

na

5 u

na

5 u

na

12

5 u

na

0.2

na

na

0.01 u

na

na

na

na

na

na

na

0.14

80

na

0.01 u

4.6

ns

ns

198

4.5

236

6

156

4.1

GP-1

05/26/94

S M I

0.7

na

na

na

na

na

na

na

na

na

na

na

na

<5

<5

na

na

na

na

na

47

52 j

na

ns

4.72 j

4.73 j

na

5.39

142

na

88

3.3

GP-1

10/05/94

S M I

<1

na

1

na

na

na

<1

na

na

na

na

na

na

na

0

na

0

na

0

na

na

76

na

ns

na

4.6 j

na

4.53

220

na

138

4.9

Concentration in mg/l; discharge in cfs; pH in standard units; specifi c conductance in //mhos/cm ;

acidity in meq/l .

T = Total na = not analyzed j = data estimated D = Dissolved u = not detected ns = not specified

n = not validated e = interference

b = below detection limi t

1

2 Table 2.1-5 of the Draft Hydrogeologic Rl list s pH as 4.41, while Table 4.2-9a list s pH as 4.44 Table 2.1-5 of the Draf t Hydrogeologi c Rl list s Spec . Cond. as 202, while Table 4.2-9a list s Spec . Cond. as 215

GM-1 [WWLJ, TP-2, an d GP-1 al l are Garibaldi Portal monitoring samples.

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07/27/95 5:34pm WPSl/cm c
July 27, FINAL * EE/CA Garibaldi Mine Site * 19

TABLE 4 SURFAC E WATER ANALYSI S - GARIBALD I WAST E ROCK PIL E (TOE SEEP ) Location

Date

Source

Flo w (cfs )

Cd-D

Cd-T

Cu-D

Cu-T

Pb-D

Pb-T

Zn-D

Zn-T

AI-D

AI-T

As-D

As-T

Ba-D

Ba-T

Bi-D

Bi-T

Cr-D

Cr-T

Fe-D

Fe-T

Mn-D

Mn-T

Ni-D

Ni-T

Se-D

Se-T

Ag-D

Ag-T

Sr-D

Sr-T

Ca-D

Ca-T

Mg-D

Mg-T

Na-D

Na-T

K -D

K -T

Si-D

GMD-1

06/09/89

W WL

N OT SAMPLE D

GMD-1

10/26/89

W WL

0.0022

0.083

0.084

0.72

0.9

< 0.005

< 0.005

15

15

12

14

0.058

0.07

<0.05

<0.05

na

na

< 0.005

< 0.005

44

43

11

11

0.02

0.02

< 0.005

< 0.005

< 0.005

< 0.005

0.05

0.05

na

22

na

7

na

1.5

na

0.5

na

GM-1

05/27/94

S M I

0.25

0.0515

0.101

1.11 j

0.97 j

0.029

0.04

10.8

17.7

14.1 j

12.5 J

0.084 j

0.056 j

na

na

na

na

na

na

31.2

58

6.15

10.4

na

na

na

na

< 0.0005

< 0.0005 uj

na

na

24.8

na

8.2

7.5

8.8

na

na

na

na

GM-1

10/05/94

S M I

0.004

0.0119 j

0.118 j

1.17

1.12

0.002

0.007

221

224

18.2

17.4

0.068 j

0.1 1 j

na

na

na

na

na

na

53.9

54.2

13.0

12.9

na

na

na

na

< 0.0005

< 0.0005

na

na

25

na

8

8

2

na

<1

na

na

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07/27/95 4:01pm WP51/cmc
July 27, 1995 FINAL * EE/CA Garibaldi Mine Site * 20

TABLE 4 (conf d) SURFAC E WATER ANALYSI S - GARIBALD I WAST E ROCK PIL E (TO E SEEP ) Location

Date

Source

Si-T

CI-D

CI-T

F -D

F -T

CN-T

Acidit y Alkalinity- T (filt ) Alkalinity- T (unfilt ) Carbonate-D

Carbonate-T

Bicarbonate-D

Bicarbonate-T

S 04 (unfilt ) S 0 4

 (filt )

pH (lab )

pH (la b filt )

pH (lab unfilt ) Spec . Cond. (lab )

pH (field ) Spe c Cond (field ) T D S

T S S

Tem p (C° )

GMD-1

06/09/89

W WL

GMD-1

10/26/89

W WL

14

na

<3

na

<0.5

<0.005

5.6

na

<5

na

<5

na

<5

na

400

3.0

ns

ns

980

2.76

1,211

550

8

4.0

GM-1

05/27/94

S M I

na

na

na

na

na

na

na

<5 u

<5 u

na

na

na

na

416

418

ns

2.85 j

2.89 j

na

3.22

1,230

675 j

na

2.3

GM-1

10/05/94

S M I

na

<1

na

na

na

na

na

0

na

n

0

na

0

na

335

ns

ns

2.9 j

na

2.85

730

596

na

6.7

Concentration in mg/l ; discharge in cfs; pH in standard units; specifi c conductance

in /t/mhos/cm ; acidity in meq/l.

T = Total na = not analyzed j = data estimated D = Dissolved u = not detected ns = not specified

GM-1 = Garibaldi Waste Rock Pile (Toe Seep) , (known as GMD-1 prior to 1994)

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July 27, 1995 FINAL *EE/CA Garibaldi Mine Site * 21

TABLE 5 SURFAC E WATER ANALYSI S - CALIFORNIA GULCH DOWNSTREAM O F GARIBALD I MIN E SIT E

Location

Date Source

Flo w (cfs ) Cd-D

Cd-T

Cu-D

Cu-T

Pb-D

Pb-T

Zn-D

Zn-T

AI-D

AI-T

As-D

As-T

Ba-D

Ba-T

Bi-D

Bi-T

Cr-D

Cr-T

Fe-D

Fe-T

Mn-D

Mn-T

Ni-D

Ni-T

Se-D

Se-T

Ag-D . Ag-T

Sr-D

Sr-T

Ca-D

Ca-T

Mg-D

Mg-T

Na-D

Na-T

K -D

K -T

Si-D

Si-T

CI-D

CG-16

06/09/89

W WL

0.0348

0.083

0.078

0.78

0.82

0.018

0.023

17

16

11

11

0.044

0.045

<0.05

<0.05

<0.5

<0.5

<0.005

<0.005

63

60

9.1

8.4

0.02

0.02

< 0.005

<0.005

< 0.005

<0.005

0.05

0.05

24

22

6.7

6.6

0.7

0.8

0.5

0.4

9.8

9.2

<3

CG-15

06/09/89

W WL

0.0889

0.12

0.11

1.1

1.0

0.02

0.021

20

20

27

26

<0.005

<0.005

<0.05

<0.05

<0.5

<0.5

< 0.005

<0.005

4.6

4.5

9.9

9.6

0.05

0.05

<0.005

< 0.005

< 0.005

< 0.005

0.09

0.09

41

39

14

13

1.6

1.4

1.5

1.3

20

18

<3

CG-1 6 AN D CG-15

10/26/89

W WL

DRY

CG-1G

05/27/94

S M I

0.8

0.075

0.078

0.74

0.69

0.016

0.017

13.5

12.8

14.1 j

13.4

0.01 j

0.008 j

na

na

na

na

na

na

14.8

15.6

6.85

6.76

na

na

na

na

< 0.0005

< 0.0005 uj

na

na

24.4

na

8.4

8.3

1.2

na

na

na

na

na

na

CG-1G

10/05/94

S MI

DRY

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July 27, 1995 FINAL * EE/CA Garibaldi Mine Site 4 22

TABL E 5 (cont'd ) SURFAC E WATE R ANALYSI S - CALIFORNIA GULCH DOWNSTREAM OF GARIBALD I MIN E SIT E

Location

Date Source

CI-T

F -D

F -T

CN-T

Acidit y Alkalinity- T (filt ) Alkalinity-T (unfilt ) Carbonate-D

Carbonate-T

Bicarbonate-D

Bicarbonate-T

S 04 (unfilt ) S O 4

 (filt )

pH (lab )

pH (lab filt )

pH (lab unfilt ) Spec . Cond. (lab )

pH (field ) Spe c Cond (field ) T D S

T S S

Tem p (° )

CG-16

06/09/89

W WL

<3

<0.5

<0.5

<0.005

6.5

na

<5

<5

<5

<5

<5

540

520

3.1

ns

ns

1000

2.56

1,136

600

<5

4.9

CG-15

06/09/89

W WL

<3

<0.5

<0.5

< 0.005

4.4

na

<5

<5

<5

<5

<5

380

370

3.6

ns

ns

730

3.41

820

600

<5

3.7

CG-16 AND

CG-15

1 0/26/89

W WL

CG-1G

05/26/94

S M I

na

na

na

na

na

<5 u

<5 u

na

na

na

na

253

2 11

ns

3.17 j

3.16 J

na

3.74

750

452 j

na

3.4

CG-1G

10/05/94 S MI

Concentration in mg/l ; discharge in cfs; pH in standard units; specifi c conductance in

//mhos/cm ; acidit y in meq/l .

T = Total na = not analyzed j = data estimated D = Dissolved u = not detected ns = not specified

CG-16 = California Gulch below Garibald i CG-15 and CG-1G = California Gulch at County Road 2

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07/27/95 5:35pm WP51/cmc
July 27, 1995 FINAL * EE/CA Garibaldi Mine Site * 23

TABLE 6 GARIBALD I GROUNDWATE R ANALYSI S

Location

Date Source

Alkalinit y (as CaC03) Bicarbonate (as CaCOS) Carbonate (as CaC03) Ca-D

Ca-T

Cl

Mg-D

Mg-T

pH (lab ) K -D

Na-D

Na-T

S 04 I D S

T S S

AI-D

AI-T

As-D

As-T

Cd-D

Cd-T

Cu-D

Cu-T

Fe-D

Fe-T

Pb-D

Pb-T

Mn-D

Mn-T

Ag-D Ag-T

Zn-D

Zn-T

pH (field ) Spec . Cond. (field ) Tem p ° C (field )

GMW1 W

10/12/94

S M I

70

70

0

53

na

<1

11

26

7.0 j

2

1

na

103

238 j

na

<0.05

1 11

<0.001

0.059

0.002

0.072

<0.01

0.37

<0.02 uj

136

< 0.001

1.82

0.05 j

20.8

< 0.0005

0.05

0.37 j

6.53

6.48

339

4.2

GMW1 W

2/8/95 Resurrection

76

na

52

51.9

11

12

7.3

3.5

3.5

99

232

932

0.05

23.6

<0.001

0.016

0.0005

0.0210

<0.01

0.15

<0.03

52

<0.001

0.39

<0.01

7.6

<0.0002

0.018

0.13

2.29

6.72

333

1.8

Concentration in mg/l; pH in standard units; specifi c conductance in

/umhos/cm.

T = Total na = not analyzed D = Dissolved u = not detected

j = data estimated

GMW1 W = Garibald i Groundwater Montorin g Wel l

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07/27/95 4:01pm WP51/cm c
July 27, 1995 FINAL * EE/CA Garibaldi Mine Site * 24

Surface water samples were also colleaed from 3 monitoring stations located downgradient of

t he Garibaldi Mine site: GM-1, CG-16, and CG-1G. For purposes of comparison with the

upgradient monitoring sites, concentration ranges for these samples are presented below:

Alkalinity - < 5 mg/1 (as CaCO3); Sulfate (D) - 211 to 520 mg/1; IDS - 452 to 675 mg/1;

pH (field) - 2.56 to 3.74; Arsenic (D) - < 0.005 to 0.084 mg/1; Cadmium (D) - 0.0119 to 0.12 mg/1 Chromium (D) - < 0.005 mg/1; Copper (D) - 0.72 to 1.17 mg/1; Iron (D) - 4.6 to 63 mg/1; Lead (D) - < 0.005 to 0.029 mg/1; Manganese (D) - 6.15 to 13 mg/1; Nickel (D) - 0.02 to 0.05 mg/1; Selenium (D) - < 0.005 mg/1; Silver (D) - < 0.0005 to < 0.005 mg/1; and, Zinc (D) - 10.8 to 221 mg/1.

Comparison of these data indicate that from upgradient to downgradient of the Garibaldi Mine

site, there is a significant decrease in alkalinity and pH and a significant increase in

concentrations of sulfate, TDS, arsenic, cadmium, copper, iron, lead, manganese, and zinc. The

observed changes in water quality suggest that the Garibaldi Mine site is a source of Acid Rock Drainage (ARD) and heavy metals to California Gulch.

Analysi s of water quality samples collected from the Garibaldi portal suggests that portal

outflow contributes to the ARD and heavy metals released from the mine site. The range of

constituent concentrations for the portal samples is provided below:

Alkalinity - < 5 mg/1 (as CaCO3); Sulfate p) - 52 to 76 mg/1; TDS - 88 to 156 mg/1;

pH'(field)-4.44 to 5.39;. Arsenic (D) - < 0.001 to 0.02 mg/1; Cadmium (D) - 0.0033 to 0.024 mg/1 Chromium (D) - < 0.005 mg/1; Copper (D) - 0.018 to 0.0882 mg/1; Iron (D) - < 0.01 to 0.08 mg/1; Lead (D) - < 0.005 to 0.009 mg/1; Manganese (D) - 0.9 to 2.06 mg/1; Nickel (D) - <0.01 mg/1; Selenium (D) - < 0.005 mg/1; Silver (D) - < 0.005 to 0.02 mg/1; and, Zinc (D) -1.2 to 3.59 mg/1.

Compared to the upgradient water quality samples, the portal samples generally exhibit lower

pH and alkalinity and contain higher concentrations of sulfate, TDS and heavy metals. However, for several parameters (sulfate, TDS, pH, arsenic, cadmium, copper, iron, lead,

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manganese, and zinc) the quality of the portal samples is notably better than the downgradient

water quality samples. Thi s suggests that other sources at the mine site, in addition to the

portal , are contributing to the poor water quality observed downgradient of Garibaldi.

T he streams were generally dry during the fall monitoring events, while the portal and toe seep

continued to flow. Seep flow rates ranged from 0.002 - 0.004 cfs during fall monitoring to 0.025

c fs during spring monitoring. Potential flow pathways through the waste rock could include

surface infiltratio n (from run-on or direct precipitation onto the pile) , portal flow not

intercepted by the Resurrection/ASARCO ditch, and/or shallow alluvial groundwater

upgradient of the waste rock pile. The toe seep could result from one or more of these flow

components.

2.3.4 Areas Affected

T he areas affected by the release of contaminants from the waste rock pile includes the surface

water in Upper California Gulch, Lower California Gulch, and the Arkansas River. In addition ,

the groundwater associated with California Gulch may be impacted by the infiltratio n of water

contaminated by metals leached from the waste rock pile. Potential groundwater contamination

however, is not addressed within this EE/CA.

2 .4 RISK ASSESSMENT

2.4.1 Scope of Risk Evaluation

A Draft Final Baseline Aquatic Ecological Risk Assessment (DFBAERA), California Gulch, Leadville, Colorado, (Roy F. Weston, Inc. [Weston] , 1994) identifies the site-wide impact of mine waste

contamination on the terrestrial and aquatic ecosystems at the California Gulch site. The DFBAERA provides a conceptual model of site-wide exposure for aquatic receptors. It identifies

surface water and sediments as the exposure pathways of concern as these media are the most

direct and significant means of exposure for ecological receptors (page 1-12, DFBAERA).

Contaminants are delivered to the surface water and sediments by erosion of contaminated solids

and by direct contact (i.e., runoff over contaminated surfaces during high flow caused by

episodic storm events or spring snowmelt, or by direct contact of contaminated material in

streams) that liberate soluble metals into the water. In addition , water passing through

contaminated material may cause contaminant loading to groundwater which eventually

discharges to surface water under certain hydrologic conditions. However, data (primarily that

collected by the Colorado Division of Wildlif e [CDOW] as discussed in Section 2.4 of the DFBAERA) provided in the DFBAERA indicates that storm events and spring snowmelt runoff

are the hydrologic conditions that cause the most significant loading of contaminants to surface

water and risk to ecological receptors.

2.4.2 Conceptual Site Model

T he DFBAERA constructed a conceptual site model to describe the exposure pathways

applicable to the site (Weston, 1994). Surface soils were identified as the primary sources of

contaminants. Primary release mechanisms are infiltration transported by groundwater flow and

surface runof f transported by surface water flow. Subsequently, groundwater, surface water and

sediment become secondary sources. Seeps from groundwater become secondary release

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mechanisms to surface water. Biotic uptake of surface water and sediment also becomes a

secondary release mechanism. Consequently, four exposure media exist: surface water, biota,

sediment and surface soil. Each impact receptors through two exposure routes: ingestion and

direct contact.

T he receptors in the aquatic ecosystem identified by the DFBAERA include algae and plankton ,

macrophytes, macroinvertebrates, amphibians, and fish (primarily trout species). Benthic

macroinvertebrates are important species of prey for trout. Other species depend on the aquatic

ecosystem including waterfowl and birds which inhabit riparian areas, and mammals.

2.4.3 Applicatio n to Garibaldi Mine Site Removal Action

2.4.3.1 Aquatic Ecosystem Risk

T he conceptual model of risk to the aquatic ecosystem provided in the DFBAERA identifies the

primary exposure pathways for the aquatic ecosystem in California Gulch and the Arkansas River as surface water runof f and sediments due to erosion from contaminated sources. A

secondary exposure pathway is the leaching of contaminated sediments and transport of the

leachate through ground water flow. As such, control of these exposure pathways is the

objective of this removal action. Control of the exposure pathways can be achieved by removal,

isolation, chemical treatment or surface stabilization. The direct contact of runof f with

contaminated surfaces will be reduced, thereby reducing erosion of these surfaces. Infiltratio n

through contaminated material will also be reduced. The effectivenes s of a removal action

alternative to control the releases of contaminants via these pathways is used to evaluate the

relative effectivenes s in reducing aquatic ecosystem risk between the various removal action

alternatives evaluated in this EE/CA.

2.4.3.2 Terrestrial Ecosystem Risk

At this time, the potential risk from uptake of metals by vegetation or direct contact with

contaminated surfaces cannot be assessed. However, it can be concluded that risk does result

from reduction in vegetation and habitat, and the alternatives in this EE/CA address that risk.

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3 .0 IDENTIFICATION OF REMOVAL ACTION OBJECTIVES

3 .1 STATUTORY LIMITS ON REMOVAL ACTIONS

T he statutory limit s on removal actions pursuant to section 104 (c)(l) of CERCLA do not appl y

to this EE/CA since it is not Fund-financed.

3 .2 REMOVA L ACTION SCOPE , GOALS , AN D OBJECTIVE S

3.2.1 Removal Action Scope

T he scope of this removal action is the remediation of the Garibaldi Mine site in Upper California Gulch. Thi s removal action is part of the overall remediation activities undertaken

in OU-4 by Resurrection Mining Company in compliance with the Consent Decree (USDC,

1994).

Thi s EE/CA evaluates interim response actions. The Final Work Plan for this EE/CA (TerraMatrix/SMI, 1994) states that the proposed removal actions are not intended to be final

actions, but are intended to ensure that the site is stabilized until remedial action begins. The

EE/CA nonetheless complies with the National Contingency Plan and applicable EPA guidance

because the EE/CA evaluates removal action alternatives that will contribute to the efficien t

performance of the long-term remedial actions for the site.

3.2.2 Removal Action Goal s

The primary removal action goal of this EE/CA is to reduce the risk to the aquatic and

terrestrial ecosystems by reducing the release of contaminated material into the environment. These releases contribute to the degradation of water quality downstream of the site in Upper California Gulch and potentiall y the Arkansas River. By minimizing run-on to, runof f from,

and infiltration through the Garibaldi Mine site, the removal action is intended to reduce the

overall potential for leaching heavy metals from the waste rock and the migration of heavy

metal contamination into surface water.

3.2.3 Removal Action Objectives

The primary objective of the selected removal action is to control releases of contaminants to

the environment in a cost-effective and timely manner. Remedial action objectives described in

t he SFS (EPA, 1993a) include:

• Control wind and water erosion of waste rock material from the source locations

• Control leaching and migration of metals from waste rock into surface water

• Control leaching and migration of metals from waste rock into groundwater

T he removal action alternatives developed for this EE/CA are intended to control the release

mechanisms of erosion and leaching, and thereby prevent the consequential degradation of water

quality in downstream receiving streams. All alternatives are evaluated based upon their

effectiveness, implementability, and cost.

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Another objective is the implementation of a non-time critical removal action that will be

compatible with the final remedial action plan that is developed for OU-4 within the Feasibilit y Stud y (FS) process.

3 .3 REMOVA L ACTION SCHEDUL E

3.3.1 Removal Schedule

Implementation of the ^referred removal action is currently scheduled to be completed in 1995,

but is dependent on a. proval of the final EE/CA report and remedial design. The detailed

schedule for field activities must be reconciled with the short construction season in Lake County. Potential delays in the preparation of the Action Memorandum that will impact

expeditious scheduling of construction activities will be considered a delay by force majeure. Completio n of the administrative process for the removal action will prevent construction until

at least the fourth quarter of 1995.

3.3.2 Planned Activities

An EE/CA must be completed for all non-time-critical removal actions as required by CERCLA. A public notice describing the EE/CA and announcing a public comment period

of at least 30 days will be published in a major local newspaper. The EE/CA is part of the

administrative record file and is subject to the public comment and comment response

requirements for the administrative record. The public comment period is expected to begin

in early Jun e 1995 and end in early July 1995. A public meting to discuss the removal action

alternatives is expected to be scheduled in mid Jun e 1995.

After the period for public comment, an Action Memorandum will be prepared by the EPA. The Action Memorandum provides a concise, written record of the decision to select an

appropriate removal action. The Action Memorandum also comprises a summary of the

comments from the public. Based on the current schedule, it is anticipated that the Action Memorandum will be finalized by the EPA in early August 1995.

Followin g issuance of the Action Memorandum, a detailed engineering document, referred to

as the Remedial Design (RD), is prepared to present the design of the selected removal action. It is anticipated that the Remedial Design process will be completed in September 1995. A

second document, entitled the Remedial Action (RA) Work Plan, is then prepared to describe

the plans and schedules for implementation of the selected removal action. Based on the current

schedule, it is anticipated that the RA Work Plan will also be completed in September 1995.

Subjec t to EPA issuance of the Action Memorandum, preparation and EPA and State approval

of the RD and RA Work Plan, and contractor selection, it is anticipated that construction of

the selected removal action will be initiated in September 1995. Assuming favorable weather

conditions, it is anticipated that construction could be completed in November 1995.

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4 .0 IDENTIFICATION AND ANALYSI S OF REMOVAL ACTION ALTERNATIVE S

4 .1 ALTERNATIV E IDENTIFICATION AN D INITIA L SCREENIN G

Thi s EE/CA discusses efficient , implementable, and cost-effective technologies that appl y to

waste rock removal actions. Guidance for the identificatio n of appropriate technologies is from

the Final Screening Feasibility Study for Remediation Alternatives at the California Gulch NPL Site, Leadville, Colorado, (SFS) particularly Section 9, Waste Rock (EPA, 1993a) and from the EPAapproved.Fz?M/ Engineering Evaluation/Cost Analysis Work Plan for the Garibaldi Mine Site (OU4) (TerraMatrix/SMI, 1994). Guidance for the preparation of this EE/CA is also provided in

the Guidance on Conducting Non-Time-Critical Removal Actions Under the Comprehensive Environmental Response, Compensation, and Liability Act (EPA, 1993b).

T he SFS retained the followin g waste rock alternatives for detailed analysis in the Feasibilit y Study :

• Alternative 1: No Action

• Alternative 2: Institutional Control

• Alternative 3: Containment (Surface Water Control)/Institutional Control

• Alternative 4: Containment (Surface Water Control, Surface Barrier)/ Institutional Controls

• Alternatives: Containment (Surface Water Control, Source Surface Control)/ Institutional Controls

• Alternative 6: Containment (Surface Water Control, Source Surface Control , Surface Barrier)/Institutional Controls

• Alternative 7: Removal/Transport/Disposal/Institutional Controls

Site-specific application s of these broadly defined alternatives were considered and a limited

number of appropriate removal action alternatives addressing waste rock were retained for

analysis within this EE/CA.

T he No Action alternative defined in the SFS was not retained for detailed analysis in the

EE/CA. In accordance with EPA guidance on conducting non-time-critical removal actions, the

purpose of the non-time-critical removal action process is to evaluate a limited number of

appropriate removal action alternatives and to implement a selected removal action consistent

with the established goals and objectives. The No Action alternative does not seek to control

sources, but leaves sources in their existing condition. As such, the No Action alternative does

not satisfy the objectives defined by the EE/CA, and is inconsistent with the purpose of the

non-time-critical removal action.

T he Institutional Control s alternative defined in the SFS was not retained for detailed analysis

in the EE/CA as a separate alternative, but is a component of other alternatives. Other

technologies identified in the SFS were retained for analysis in the EE/CA. While the EE/CA

incorporates these technologies in alternatives, the structure of presentation has been modified

from the SFS to reflect the site-specific nature and extent of Garibaldi waste rock. For instance,

a surface barrier as defined under Alternatives 4 and 6 in the SFS is not analyzed further within

this EE/CA, since it would not be effective given the nature and extent of site contamination.

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A simple cover, however, has been included in Alternative C which acts as both a source surface

control and a surface barrier. Thi s structure is consistent with the alternatives identified in the

EPA-approved EE/CA Work Plan.

T he alternatives analyzed incorporate site-specific application s of the SFS Alternatives . In

addition , the alternatives are consistent with the nature and extent of contamination and the

removal action objectives. The removal action alternatives analyzed in further detail within this

EE/CA include:

• Alternative A: Surface Water and Portal Flo w Diversion — Thi s alternative

entails the interception and diversion of stream flow

(including portal flow ) around the waste rock by

reconstruction of existing channels and/or construction of

new channels to prevent run-on to and/or infiltratio n

through the waste rock. Alternative A is shown on Drawing 2 and corresponds to Alternative 3 as presented in

t he SFS (EPA, 1993a).

• Alternative B: Surface Water, Portal Flow , and Shallow Alluvial Groundwater Diversion — Thi s alternative includes the

interception and diversion of stream flow (including portal

flow ) around the waste rock by reconstruction of existing

channels and/or construction of new channels to prevent

run-on to and/or infiltratio n through the waste rock. It

also entails the diversion of shallow alluvial groundwater

flow around the waste rock by construction of groundwater

interceptor trenches. Alternative B is shown on Drawing

3 and also corresponds to Alternative 3 as presented in the S FS (EPA, 1993a).

• Alternative C: Surface Water, Portal Flow , and Shallow Alluvial Groundwater Diversion/Regrading/Simple Cover — Thi s

alternative includes the interception and diversion of stream

flow (including portal flow ) around the waste rock by

reconstruction of existing channels and/or construction of

new channels to prevent run-on to and/or infiltratio n

through the waste rock; diversion of shallow alluvial

groundwater flow around the waste rock by construction of

groundwater interceptor trenches; and regrading of the

waste rock pile and construction of a simple cover to

minimize infiltratio n through the waste rock pile and

expedite non-erosive runof f from the pile surface. The

simple cover would be designed as both a source surface

control and surface barrier. Alternative C is shown in Drawing 4 and corresponds to Alternative 5 as presented in

t he SFS (EPA, 1993a).

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• Alternative D: Waste Rock Removal — Thi s alternative entails the removal

of the waste rock from the site and transport to the Oregon Gulch Tailin g Impoundment for disposal. It also includes

reestablishment of the original drainage channel. Alternative D, shown on Drawing 5, corresponds to Alternative 7 as presented in the SFS (EPA, 1993a).

Institutional controls (Alternative 2 in the SFS), including posted warnings, information and

education programs, and/or other controls would also be incorporated within the removal

action alternatives evaluated, as approved by EPA.

The criteria utilized in the analysis of the four removal action alternatives are defined in the Guidance on Conducting Non-Time-Critical Removal Actions Under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) (EPA, 1993b), and include

effectiveness , implementability , and cost. These EPA criteria are utilized as screening criteria

to aid in the selection of the appropriate removal action for the Garibaldi Mine site. In

addition, the Work Area. Management Plan (WAMP) (USDC, 1994) performance criteria of

erosion stabilit y and flow capacity and stabilit y are utilized in evaluating the effectivenes s of the

removal action alternatives in meeting the removal action objectives (RAOs). RAOs are further

discussed in Section 3.2.

After detailed evaluation of the individual removal action alternatives, a comparative analysis

of these alternatives is presented in Section 5.0 identifies the advantages and disadvantages of

each alternative relative to one another considering the EPA criteria of effectiveness,

implementability , and cost.

4 .2 EVALUATION CRITERIA

EPA guidance (EPA, 1993a) prescribes the evaluation of removal alternatives according to three

main criteria: effectiveness, implementability and cost. These criteria are defined in the Guidance on Conducting Non-Time-Critical Removal Actions Under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) (EPA, 1993b) and are

utilized as screening criteria to aid in the selection of the appropriate removal action for the Garibaldi Mine site. These criteria are described below.

Effectiveness — The effectiveness of an alternative refers to its ability to meet the objeaives

within the scope of the removal action. Thi s criterion is evaluated for:

( 1) Overall protection of public health and the environment, comprising of:

how each alternative achieves adequate protection

how each alternative reduces risk

identification of any unacceptable short-term impacts;

( 2) Compliance with Applicable or Relevant and Appropriate Requirements (ARARs)

and other guidance criteria, comprising of:

summary of potential ARARs

strategy for compliance with ARARs;

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( 3) Long-term effectivenes s and permanence, comprising of:

assessment of risk from residual waste

contribution to future remedial objectives

adequacy and reliability of controls;

( 4) Reduction of toxicity, mobility or volume through treatment, comprising of:

treatment process employed and nature of materials treated

amount of contaminated material to be treated

degree of reduction expected in toxicity, mobility or volume

degree to which treatment is irreversible

type and quantity of treatment residuals

whether the alternative satisfies CERCLA's preference for treatment; and

( 5) Short-term effectiveness , comprising of:

protection of the community

protection of the workers

no adverse impacts to the environment

time to achievement of objectives

Implementability — Implementabilit y of an alternative addresses its technical and administrative

feasibility and the availability of necessary services and materials. The evaluation is based on:

( 1) Technical feasibility , comprising of:

ability of the technology to implement the remedy

reliability of the technology

influence of climatic conditions

post-removal site controls

integration with final remediation;

( 2) Administrative feasibility , comprising of:

statutory limits

permits and waivers;

( 3) Availability of services and materials, comprising of:

personnel and technology

off-site treatment, storage and disposal

services and materials

availability of full-scale technology;

( 4) State/EPA acceptance; and

( 5) Community acceptance.

Cost — Thi s is an order-of-magnitude evaluation of projea costs, which is comprised of direct

capital costs, indirect capital costs, and post-removal site control/operation and maintenance

costs. A present worth analysis will be carried out for the post-removal site control/operation

and maintenance costs using a 7% discount rate (EPA, 1987b), assuming that the final

remediation will occur within four years.

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Performance criteria described in the WAMP (USDC, 1994) will also be utilized to evaluate the

effectivenes s of the removal action alternatives in aieeting RAOs.

Diversion ditches (Alternatives A, B, and C) were designed to safely convey the peak discharge

from the 100-year, 24-hour storm. The HEC-1 hydrologic model was utilized to simulate

surface runof f resulting from the design storm. Results are presented in Appendix B. Surface

water diversions were sized using Manning' s Equation for open channel flow.

T he Hydrologic Evaluation of Landfil l Performance (HELP) model was utilized to predict

infiltratio n through the waste rock pile with and without regrading and a simple cover

(Alternatives A, B, and C). HELP results are included in Appendix C. The SEDCAD + model,

utilizin g the Revised Universal Soi l Loss Equation (RUSLE) subroutine, was used to determine

the sediment yield of the waste rock pile with and without regrading and a simple cover

(Alternatives A, B, and C). Sedimen t loadin g calculations are included in Appendix D. A

stabilit y analysis, using XSTABL software, was also performed for the waste rock pile with and

without regrading and a simple cover (Alternatives A, B, and C). The XSTABL analysis is

included in Appendix E.

4 .3 ALTERNATIV E A - SURFACE WATER AND PORTAL FLOW DIVERSION

4.3.1 Description of Alternative A

Alternative A entails the diversipn of surface water flow (including portal flow ) around the

waste rock by reconstruction of existing channels and the construction of new channels to

prevent run-on to the waste rock.

4.3.1.1 Diversion Channels/Acces s Road Improvement s

Under Alternative A, 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. Diversion Ditch 2 located along the northeast edge of the

waste rock pile would divert runoff 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 would be routed through Diversion Ditch 2. 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 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 pile to the natural stream bed. Two

36-inch culverts would be installed in the upper portion of Diversion Ditch 4 to route the runof f

under the existing access road. 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.

The diversion ditches were designed to safely convey the peak discharge from the 100-year, 24-

hour event. All runoff calculations were performed utilizing the HEC-1 Computer Model

developed by U.S. Army Corps of Engineers. HEC-1 is a hydrologic and hydraulic calculation

model adapted for use on a PC system. The HEC-1 hydrologic model calculates peak flow and

runof f volume via a numerical modelin g technique based on user inputs of a design storm event.

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T he methodology and assumptions used in calculatin g runoff , and model output s are included

in Appendix B, HEC-1 Model . The ditch design schedule is presented on Drawing 2.

As shown on Drawing 2, all diversion ditches would be trapezoidal ditches with 2-foot bottoms

and 2H:1V side slopes. Diversion Ditches 2 and 4 would be lined with concrete (or an

alternative lining system) for erosional stability . Ditches which do not cross and/or are not

adjacent to the pile will not be lined with concrete. Diversion Ditch 1 would be grass-lined and Diversion Ditch 3 would be lined with riprap. Alternative ditch lining systems will be further

evaluated in the Remedial Design.

Under this alternative, the access road to the Garibaldi Mine Site would require improvement

for use by heavy equipment and the hauling of materials to the site. Approximatel y 500 feet

of the access road would be improved by minor regrading and blading. Culverts would be

replaced, as shown on Drawing 2.

4.3.1.2 Construction

Best management practices (BMPs) would be utilized during all construction activities at the site. Temporary sediment control structures, including placement of straw bales, sediment control

fences, or small berms will be utilized to control sediment runof f from the site. In addition ,

dust control, (including use of a water truck) would be practiced during construction.

4.3.2 Analysi s of Alternative A

EPA guidance (EPA, 1993b) prescribes the evaluation of removal action alternatives according

to three main criteria: effectiveness , implementability , and cost. An evaluation of Alternative A utilizin g these criteria follows .

4.3.2.1 Effectivenes s of Alternative A

T he effectivenes s of an alternative refers to its ability to meet the objectives within the scope

of the removal action. The effectivenes s of an alternative is evaluated based upon overall

protection of public health and the environment, compliance with ARARs, long-term

effectiveness , reduction of toxicity, mobility , or volume, and short-term effectiveness.

Overall Protection of Public Health and the Environment: Four components of flow through

the waste rock have been identified, including surface water run-on; direct precipitation onto

t he pile; shallow alluvial groundwater; and portal flow. Thi s alternative would divert surface

run-on and portal flow around the waste rock pile and minimize leaching and erosional releases

from these flow components. Surface infiltration (from direct precipitation onto the pile) and

shallow alluvial groundwater could, however continue to flow through the pile and contribute

to the leaching and migration of metals from the waste rock. Infiltratio n through the pile (from

direct precipitation on the pile) was estimated at 1.4 inches per year, utilizin g the HELP model

(Appendix C). In addition, erosion associated with these flow components would continue. Sediment yield was estimated at 6.1 tons/acre/year utilizing the RUSLE equation (Appendix D). The stability evaluation indicates that the waste rock has a Factor of Safety of 1.0 or greater, as

described in Appendix E.

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Compliance With ARARs: Appendix F presents a list of potential ARARs for the remediation

of the California Gulch site, as revised by EPA. Compliance with ARARs (including cultural

resources ARARs, the Cl: n Air Act, the Colorado Air Quality Control Act, the stormwater

program of the National Pollutan t Discharge Elimination System, the Colorado Noise Abatement Act , and the Colorado Mined Land Reclamation Act) will be achieved for this

removal action alternative, as required by EPA.

Long-Term Effectiveness: Thi s alternative, designed for the 100-year flood event, would be

effective in diverting, and stable under, the 100-year peak flow. As discussed previously, it

would be effective in diverting surface run-on and portal flo w around the waste rock. Since less

water would come in contact with the source (waste rock), overall metal loading to Upper California Gulch through leaching and/or erosion would be reduced.

Reduction of Toxicity, Mobility, or Volume: Under this alternative, the overall volume of

water flowin g through/over the waste rock source material would be reduced, thus reducing

erosion and the leaching and migration of metals from the waste rock.

Short-Term Effectiveness: Potential short-term risks to the community resulting from the

implementation of this removal action include dust emissions and increased road traffic . The Garibaldi Mine Site , however is located approximately 3 miles from the populated areas of Leadville and is in a topographicall y isolated area. In addition , short-term risk factors would

be effectivel y mitigated through the implementation of standard construction practices. Dust

abatement practices would be followed during construction activities. Additional road traffic

would be light and limited to the immediate vicinity of the Garibaldi Mine Site , except during mobilization, demobilization, and the delivery of construction materials.

Risk to workers during implementation of this removal action may result from dust inhalation,

contact with contaminated materials, and other industrial safety hazards. Dust abatement

measures during construction would effectivel y manage dust exposure. Contact with

contaminated materials through accidental exposure is unlikely to occur to a trained remediation

worker, because appropriate safety measures would minimize this and other potential hazards.

Impact to the environment during implementation of this removal action may result from

accidental discharge of runof f with suspended solids from contaminated materials disturbed

during construction activities. Potential releases would be minimized through the use of BMPs,

discussed previously in Section 4.3.1.2.

4.3.2.2 Implementabilit y of Alternative A

T he implementabilit y of an alternative addresses its technical and administrative feasibilit y and

the availability of necessary services and materials. The evaluation is based on technical

feasibility , administrative feasibility , availability of services and materials, state/EPA acceptance,

and community acceptance.

Technical Feasibility: The technologies used in this alternative are common and widely

accepted. The time-frame for implementation can occur within the short construction season

of the Leadville area. The reliability of design and implementation is based on established

practice. Climatic conditions will not interfere with "he operation of this removal action

alternative.

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Administrative Feasibility: Compliance with statutory limit s on removal actions will not be

necessary since this removal action is not CERCLA fund-financed. Construction permits will

not be necessary. Certain federal permits, such as a stormwater permit, may be required. Therefore, the schedule for this alternative could be hindered by administrative requirements.

Availability of Services and Materials: Thi s alternative can be implemented using commonly

available earth-moving equipment. Materials and personnel will also be readily available.

State, EPA and Community Acceptance: It is believed that the EPA and State of Colorado

will fin d elements of this alternative acceptable. However, this criterion will be further

addressed in the Action Memorandum.

T he EE/CA process requires public review, and comments from the public will also be

addressed in the Action Memorandum. Community acceptance of this removal action

alternative is expected.

4.3.2.3 Cost of Alternative A

The cost evaluation is an order-of-magnitude evaluation of project costs and is comprised of

direct capital costs, indirect capital costs, and post-removal site control/operation and

maintenance costs.

The cost estimate for Alternative A is summarized in Table 7, Alternative A Cost Summary. Total costs are estimated at $175,615, and include $93,416 for direct capital costs, $57,918 for

indirect capital costs and $24,281 for post removal site control costs (present worth). Further

cost estimate data are presented in Appendix G.

TABLE 7 ALTERNATIVE A - COST SUMMARY

Direct Capital Costs

Indirect Capital Costs

Post-Removal Site Control Costs (present worth)

TOTA L

$93,416

$57,918

$24,281

$175,615

4 .4 ALTERNATIVE B - SURFACE WATER , PORTAL FLOW , AND SHALLOW ALLUVIA L GROUNOWATE R DIVERSIO N

4.4.1 Description of Alternative B

Alternative B entails the diversion of stream flow (including portal flow ) around the waste rock

by the reconstruction of existing channels and the construction of new channels to prevent runon to and/or infiltration through the waste rock. It also involves the diversion of shallow

alluvial groundwater flow around the waste rock by construction of groundwater interceptor

trenches.

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4.4.1.1 Diversion Channels/Acces s Road Improvement s

Diversion channels and access road improvements constructed under Alternative B would be the

same as described under Alternative A in Section 4.3.1.1, with the followin g exceptions:

• Diversion Ditch 2 would also convey flow from the eastern groundwater

interceptor trench, as further discussed below under Section 4.4.1.2.

• Diversion Ditch 4 would also convey flow from the northern groundwater

interceptor trench, as further discussed below under Section 4.4.1.2.

Alternative B is portrayed in Drawing 3.

4.4.1.2 Groundwater Interceptor Trenches

Under Alternative B, two groundwater interceptor trenches would be constructed, as shown in Drawing 3. The groundwater interceptor trench for the eastern channel would divert flow into Diversion Ditch 2 and 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 (HDPE) liner. A filter fabric would

be installed around the clean gravel to reduce siltation and clogging. A perforated polyvinyl

chloride (PVC) pipe would be placed in the bottom of the trench. The 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.

4.4.1.3 Construction

BMPs, as described under Alternative A in Section 4.3.1.2 would be utilized during all

construction activities at the site.

4.4.2 Analysi s of Alternative B

4.4.2.1 Effectivenes s of Alternative B

Overall Protection of Public Health and the Environment — As discussed under Alternative A, four components of flow through the waste rock have been identified, including surface

water run-on; direct precipitation onto the pile; shallow alluvial groundwater; and portal flow. Thi s alternative would minimize the contact of three of these components with the waste rock

and thereby reduce leaching and erosional releases from these flow components. Under Alternative B, surface run-on and portal flow would be diverted around the waste rock pile and

the shallow alluvial groundwater would be diverted from the pile through the groundwater

interceptor trench to the diversion channels. Surface infiltration from direct precipitation

would, however continue to flow through the pile and contribute to the leaching and migration

of metals from the waste rock. Infiltration through the pile (from direct precipitation on the

pile) was estimated at 1.4 inches per year, utilizing the HELP model (Appendix C). In addition,

erosion associated with this flow component would continue. Sediment yield was estimated at

6.1 tons per acre per year utilizing the RUSLE equation (Appendix D). The stability evaluation

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indicates that the waste rock pile has a Factor of Safet y of 1.0 or greater, as described in Appendix E.

Compliance "With ARARs — Appendix F presents a lis t of potential ARARs for the

remediation of the California Gulch site, as revised by EPA. Compliance with ARARs

(includin g cultural resources ARARs, the Clean Air Act, the Colorado Air Quality Control Act,

t he stormwater program of the National Pollutan t Discharge Elimination System, the Colorado Noise Abatement Act and the Colorado Mined Land Reclamation Act) will be achieved for this

removal action alternative, as required.

Long-Term Effectiveness — Thi s alternative, designed for the 100-year flood event, would be

effective in diverting, and stable under, the 100-year peak flow. As discussed previously, it

would be effective in diverting surface run-on, portal flow, and shallow alluvial groundwater

around the waste rock. While it is anticipated that the groundwater interceptor trenches will

divert a portion of the alluvial groundwater around the pile, the overall effectivenes s of totall y

eliminating this source of contact with the pile is uncertain. Since less water would come in

contact with the source (waste rock), however, overall metals loadin g to Upper California Gulch

would be reduced.

Reduction of Toxicity, Mobility, or Volume — Under this alternative, the overall volume of

water flowin g through the waste rock source material would be reduced, thus reducing the

leaching and migration of metals from the waste rock.

Short-Term Effectiveness — Potential short-term risks to the community resulting from the

implementation of this removal action include dust emissions and increased road traffic . The Garibaldi Mine Site , however is located approximately 3 miles from the populated areas of Leadville and is in a topographicall y isolated area. In addition, short-term risk factors would

be effectivel y mitigated through the implementation of standard construction practices. Dust

abatement practices would be followed during construction activities. Additional road traffic

would be light and limited to the immediate vicinity of the Garibaldi Mine Site, except during mobilization, demobilization, and the delivery of construction materials.

Risk to workers during implementation of this removal action may result from dust inhalation,

contact vith contaminated materials, and other industrial safety hazards. Dust abatement

measures during construction would effectively manage dust exposure. Contact with

contaminated materials through accidental exposure is unlikely to occur to a trained remediation

worker, because appropriate safety measures would minimize this and other potential hazards.

Impact to the environment during implementation of this removal action may result from

accidental discharge of runof f with suspended solids from contaminated materials disturbed

during construction activities. Potential releases would be minimized through the use of BMPs,

discussed previously in Section 4.3.1.2.

4.4.2.2 Implementabilit y of Alternative B

Technical Feasibility — The technologies used in this alternative are common and widely

accepted. The time-frame for implementation can occur within the short construction season

of the Leadville area. The reliability of design and implementation is based on established

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practice. Climatic conditions will not interfere with the operation of this removal action

alternative.

Administrative Feasibility — Compliance with statutory limit s on removal actions will not be

necessary since this removal action is not CERCLA fund-financed. Construction permits will

not be necessary. Certain federal permits, such as a stormwater permit, may be required. Therefore, the schedule for this alternative could be hindered by administrative requirements.

Availability of Services and Materials — Thi s alternative can be implemented using commonly

available earth-moving equipment. Materials and personnel will also be readily available.

State, EPA and Community Acceptance — It is believed that the EPA and State of Colorado

will fin d elements of this alternative acceptable. However, this criterion will be further

addressed in the Action Memorandum.

T he EE/CA process requires public review, and comments from the public will be addressed

in the Action Memorandum. Community acceptance of this removal action alternative is

expected.

4.4.2.3 Cost of Alternative B

The cost estimate for Alternative B is summarized in Table 8, Alternative B Cost Summary. Total costs are estimated at $208,039, and include $113,431 for direct capital costs, $70,327 for

indirect capital costs and $24,281 for post removal site control costs (present worth). Further

cost estimate data are presented in Appendix G.

TABLE 8 ALTERNATIVE B - COST SUMMARY

Direct Capital Costs

Indirec t Capital Costs

Post-Removal Site Control Costs (presen t worth)

TOTA L

$113,431

$70,327

$24,281

$208,039

4 .5 ALTERNATIV E C - SURFACE WATER , PORTAL FLOW , AND SHALLOW ALLUVIA L GROUNDWATE R DIVERSION/REGRADING/SIMPL E COVER

4.5.1 Description of Alternative C

Alternative C entails the diversion of stream flow (including portal flow ) around the waste rock

by the reconstruction of existing channels and the construction of new channels to prevent runon to and/or infiltratio n through the waste rock. It also involves the diversion of shallow

alluvial groundwater flow around the waste rock by construction of groundwater interceptor

trenches. Additionally , the pile surface would be regraded and a low permeability simple cover

would be constructed to promote runoff and minimize infiltratio n through the piles.

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4.5.1.1 Diversion Channels/Acces s Road Improvement s

Diversion channels and access road improvements constructed under Alternative C would be

the same as described under Alternative B in Section 4.4.1.1.

Alternative C is portrayed in Drawing 4.

4.5.1.2 Groundwater Interceptor Trenches

The groundwater interceptor trenches constructed under Alternative C would be the same as

described under Alternative B in Section 4.4.1.2.

4.5.1.3 Regrading/Simpl e Cover

T he waste rock pile would be regraded and stabilized to eliminate ponding, promote drainage,

and create a surface configuration that is erosionally stable. No terrain will be regraded steeper

than 3H:1V as shown on Drawing 4. The Factor of Safet y of the regraded pil e was determined

to be 2.0 under pseudostatic conditions and greater than 2.0 under drained conditions. Regrading would require approximately 3,100 cy of material movement.

Stabilized surfaces would be covered with low permeability borrow soil amended with organic

matter and fertilizer. The amendment would be mixed into the top 12 inches of the soil by

discing or using other appropriate methods. Hydroseeding, involving the applicatio n of a

mixture of seed, fertilizer, and a tackifier may be used at the site. Hydroseedin g would prevent

excessive erosion of the site before a productive vegetative cover is established.

4.5.1.4 Construction

BMPs, as described under Alternative A in Section 4.3.1.2 would be utilized during all

construction activities at the site.

4.5.2 Analysi s of Alternative C

4.5.2.1 Effectivenes s of Alternative C

Overall Protection of Public Health and the Environment — As discussed under Alternative A, four components of flow through the waste rock have been identified, including surface

water run-on; direct precipitation onto the pile; shallow alluvial groundwater; and portal flow. Thi s alternative would minimize the contact of all four of these components with the waste rock

and thereby reduce leaching and erosional releases from these flow components. Under Alternative C, surface run-on and portal flow would be diverted around the waste rock pile and

t he shallow alluvial groundwater would be diverted from the pile through the groundwater

interceptor trench to the diversion channels. Surface infiltratio n through the pile and the

erosional release of sediment would be minimized through the construction of the simple cover. Surface infiltratio n through the pile (from direct precipitation on the pile) would be reduced to

approximately 0.8 inches per year (see Appendix C) and sediment yield would be reduced to

approximately 1 ton per acre per year (see Appendix D). Under this alternative, the Factor of Safet y for the waste rock pile is estimated at 2.0 using the XSTABL model, as described in Appendix E.

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Compliance With ARARs — Appendix F presents a lis t of potential ARARs for the

remediation of the California Gulch site, as revised by EPA. Compliance with ARARs (including cultural resources ARARs, the Clean Air Act, the Colorado Air Quality Control Act,

t he storm-water program of the National Pollutan t Discharge Elimination System, the Colorado Noise Abatement Act and the Colorado Mined Land Reclamation Act) will be achieved for this

removal action alternative, as required.

Long-Term Effectiveness — Thi s alternative, designed for the 100-year flood event, would be

effective in diverting, and stable under, the 100-year peak flow. As discussed previously, it

would be effective in diverting surface run-on, portal flow, and shallow alluvial groundwater

around the waste rock and would minimize infiltration flow through the waste rock. While it

is anticipated that the groundwater interceptor trenches will divert a portion of the alluvial

groundwater around the pile, the overall effectivenes s of totally eliminating this source of

contact with the pile is uncertain. Since less water would come in contact with the source

(waste rock), however, overall metals loading to Upper California Gulch would be reduced.

Reduction of Toxicity, Mobility, or Volume — Under this alternative, the overall volume of

water flowin g through the waste rock source material would be reduced, thus reducing the

leaching and migration of metals from the waste rock.

Short-Term Effectiveness — Potential short-term risks to the community resulting from the

implementation of this removal action include dust emissions and increased road traffic . The Garibaldi Mine Site, however is located approximately 3 miles from the populated areas of Leadville and is in a topographicall y isolated area. In addition, short-term risk factors would

be effectively mitigated through the implementation of standard construction practices. Dust

abatement practices would be followed during construction activities. Additional road traffic

would be light and limited to the immediate vicinity of the Garibaldi Mine Site, except during

mobilization, demobilization, and the delivery of construction materials.

Risk to workers during implementation of this removal action may result from dust inhalation,

contact with contaminated materials, and other industrial safety hazards. Dust abatement

measures during construction would effectively manage dust exposure. Contact with

contaminated materials through accidental exposure is unlikely to occur to a trained remediation

worker, because appropriate safety measures would minimize this and other potential hazards.

Impact to the environment during implementation of this removal action may result from

accidental discharge of runof f with suspended solids from contaminated materials disturbed

during construction activities. Potential releases would be minimized through the use of BMPs,

discussed previously in Section 4.3.1.2.

4.5.2.2 Implementabilit y of Alternative C

Technical Feasibility — The technologies used in this alternative are common and widely

accepted. The time-frame for implementation can occur within the short construction season

of the Leadville area. The reliability of design and implementation is based on established

practice. Construction of a simple cover, however, would involve the location and transport

of suitable cover material. Climatic conditions will not interfere with the operation of this

removal action alternative.

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Administrative Feasibility — Compliance with statutory limit s on removal actions will not be

necessary since this removal action is not CERCLA fund-financed. Construction permits will

not be necessary. Certain federal permits, such as a stormwater permit, may be required. Therefore, the schedule for this alternative could be hindered by administrative requirements.

Availability of Services and Materials — Thi s alternative can be implemented using commonly

available earth-moving equipment. Materials and personnel will also be readily available.

State, EPA and Community Acceptance — It is believed that the EPA and State of Colorado

will fin d elements of this alternative acceptable. However, this criterion will be further

addressed in the Action Memorandum.

T he EE/CA process requires public review, and comments from the public will be addressed

in the Action Memorandum. Community acceptance of this removal action alternative is

uncertain, since it would involve covering an area that could have historic value to the

community.

4.5.2.3 Cost of Alternative C

T he cost estimate for Alternative C is summarized in Table 9, Alternative C Cost Summary. Total costs are estimated at $324,233 and include $174,188 for direct capital costs, $107,997 for

indirect capital costs and $42,048 for post removal site control costs (present worth). Further

cost estimate data are presented in Appendix G.

TABLE 9 ALTERNATIVE C - COST SUMMARY

Direct Capital Costs

Indirec t Capital Costs

Post-Removal Site Control Costs (present worth)

TOTA L

$174,188

$107,997

$42,048

$324,233

4 .6 ALTERNATIVE D - WASTE ROCK REMOVAL

4.6.1 Description of Alternative D

Alternative D entails the removal of the waste rock material and transport to the Oregon Gulch Tailin g Impoundment for disposal/utilization in remediation measures in OU-10. Waste rock

would be removed down to the existing channel grade, loaded with an excavator, and

transported via 10 cubic yard trucks. Trucks would travel from the Garibaldi site along the Garibaldi access road to Lake County Road 2. From Lake County Road 2, trucks would

proceed to the access road to the Yak Tunnel Treatment Plant. A new haul road would be

constructed from the plant, over the ridge to the northeast of the plant to the Oregon Gulch Tailin g Impoundment. Construction of the new haul road would provide a shorter haul route,

thus reducing removal costs. In addition, it would eliminate construction traffic through town. Under this alternative, approximately 500 feet of the Garibaldi access road would be repaired

and approximately 1,600 feet of new road would be constructed. Thi s alternative would require

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that additional cultural resource inventory and evaluation be conducted for road improvements

and new road construction. The proposed haul route is delineated on Figure 2. Alternative D

is shown on Drawing 5.

BMPs, as described under Alternative A in Section 4.3.1.2 would be utilized during all

construction activities at the site.

4.6.2 Analysi s of Alternative D

4.6.2.1 Effectivenes s of Alternative D

Overall Protection of Public Health and the Environment: As discussed under Alternative A, four components of flow through the waste rock have been identified, including surface

water run-on; direct precipitation onto the pile; shallow alluvial groundwater; and portal flow. Thi s alternative would eliminate the contact of all four of these components with the waste rock

and thereby eliminate leaching and erosional releases from these flow components. Under Alternative D, the waste rock would be removed from the site and water contact with this

source would be eliminated. The waste rock would be disposed in the Oregon Gulch Tailin g Impoundment and would be remediated along with the overall OU-10 remediation plans to be

determined under the OU-10 Feasibilit y Study . Under this alternative, flow from the Garibaldi

portal would continue to flow through Upper California Gulch.

Compliance With ARARs — Appendix F presents a list of potential ARARs for the

remediation of the California Gulch site, as revised by EPA. Compliance with ARARs (including cultural resources ARARs, the Clean Air Act, the Colorado Air Quality Control Act,

the stormwater program of the National Pollutant Discharge Elimination System, the Colorado Noise Abatement Act and the Colorado Mined Land Reclamation Act) will be achieved for this

removal action alternative, as required.

Long-Term Effectiveness: Under Alternative B, the source material would be relocated

permanently and erosional and leaching releases from the Garibaldi site would be eliminated. The waste rock, however, would be relocated to OU-10 and require remediation under the OU10 Feasibilit y Stud y activities. In addition, flo w from the Garibaldi portal would continue to

flo w through Upper California Gulch.

Reduction of Toxicity, Mobility, or Volume: Under this alternative, the waste rock source

material would be relocated, thus eliminating the leaching and migration of metals from the

waste rock at the Garibaldi site. The waste rock would, however contribute to the metals

loading at its new location in OU-iC, until that site undergoes remediation. In addition, flow

from the Garibaldi portal would continue to flow through Upper California Gulch.

Short-Term Effectiveness: Potential short-term risks to the community resulting from the

implementation of this removal action include dust emissions and increased road traffic. The Garibaldi Mine Site, however is located approximately 3 miles from the populated areas of Leadville and is in a topographically isolated area. In addition, short-term risk factors would

be effectivel y mitigated through the implementation of standard construction practices. Dust

abatement practices would be followed during construction activities. Additional road traffic

would result from the implementation of this alternative, between the* Garibaldi site and the Oregon Gulch Tailin g Impoundment. For a period of approximately 1 month, 130 round trips

of truck hauling would occur per day, assuming use of a 10 cubic yard dump truck.

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Risk to workers during implementation of this removal action may result from dust inhalation,

contact with contaminated materials, and other industrial safety hazards. Dust abatement

measures during construction would effectivel y manage dust exposure. Contact with

contaminated materials through accidental exposure is unlikely to occur to a trained remediation

worker, because appropriate safety measures would minimize this and other potential hazards.

Impact to the environment during implementation of this removal action may result from

accidental discharge of runoff with suspended solids from contaminated materials disturbed

during construction activities. Potential releases would be minimized through the use of BMPs,

discussed previously in Section 4.3.1.2.

4.6.2.2 Implementabilit y of Alternative D

Technical Feasibility: The technologies used in this alternative are common and widely

accepted. The time-frame for implementation can occur within the short construction season

of the Leadville area. The reliability of design and implementation is based on established

practice. Climatic conditions will not interfere with the operation of this removal action

alternative.

Administrative Feasibility: Compliance with statutory limits on removal actions will not be

necessary since this removal action is not CERCLA fund-financed. Construction permits will

not be necessary. Certain federal permits, such as a stormwater permit, may be required. Therefore, the schedule for this alternative could be hindered by administrative requirements. Several administrative issues associated with Alternative D must, however, be resolved prior to

implementation. These include cultural resource inventory work and compliance with Section

106 of the National Historic Preservation Act; access/ownership issues associated with the haul

road construction; potential regulatory ramifications associated with depositin g waste rock

material in Oregon Gulch; and concerns over utilizing Oregon Gulch as a deposit area for waste

rock material.

Availability of Services and Materials: Thi s alternative can be implemented using commonly

available earth-moving equipment. Materials and personnel will also be readily available.

State, EPA and Community Acceptance: It is believed that the EPA and State of Colorado

will fin d this alternative acceptable. Both the State and EPA have expressed interest in the past

in the Removal Alternative. Thi s criterion, however, will be further addressed in the Action Memorandum.

T he EE/CA process requires public review, and comments from the public will be addressed

in the Action Memorandum. Community acceptance of this removal action alternative is

uncertain, since it would involve removing material from an area that could have historic value

to the community.

4.6.2.3 Cost of Alternative D

The cost estimate for Alternative D is summarized in Table 10, Alternative D Cost Summary. Total costs are estimated at $531,191, and include $301,940 for direct capital costs, $187,203 for

indirect capital costs and $42,048 for post removal site control costs (present worth). Further

cost estimate data are presented in Appendix D.

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TABLE 10 ALTERNATIVE D - COST SUMMARY Direct Capital Costs

Indirec t Capita l Cost s Post-Removal Site Control Cost s (presen t worth) TOTA L

$301,940

$187,203

$42,048

$531,191

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5 .0 COMPARATIVE ANALYSIS OF

REMOVAL ACTION ALTERNATIVE S

Thi s section provides a comparison of removal alternatives based on criteria contained in the Guidance on Conducting Non-Time-Critical Removal Actions Under CERCLA (EPA, 1993b) and

discussed in Section 4.2 of this EE/CA Report. In this evaluation, the relative advantages and

disadvantages of the alternatives are directly compared in a matrix evaluation. Criteria used in

this comparative analysis include the same three major categories (effectiveness ,

implementability , and cost) used to individually assess each alternative in Section 4.0.

T he comparative analysis of the four alternatives considered within this EE/CA is presented in Table 11, Comparison of Alternatives. Alternatives are rated poor, fair, good, or very good

relative to the evaluation criteria and each other. Please refer to Section 4.0 for a more complete

discussion of the evaluation of the individual alternatives utilizin g the effectiveness,

implementability , and cost criteria.

TABLE 1 1 COMPARISON OF ALTERNATIVES

Alternative A Alternative B Alternative C Alternative D

Effectivenes s

Overall Protection of Human Health and Environment

Complianc e with ARARs

Long-Term Effectivenes s

Reduction of Toxicity , Mobility , Volume

Short-Term Effectivenes s

F

G

F

F

G

G

G

G

G

G

G

G

G

G

G

VG

G

VG

VG

F

Implementabilit y Technical Feasibilit y Administrative Feasibilit y Availabilit y of Services and Material s

Anticipated State/EPA Acceptance

Anticipated Community Acceptance

G

G

G

G

G

G

G

G

G

G

F

G

G

G

F

G

F

G

VG

F

Cost

Total Direct Capital Costs

Indirec t Capital Costs

Post-Removed Site Control/Other

Gran d Total

$93,416

$57,918

$24,281

$175,615

$113,431

$70,327

$24,281

$208,039

$174,188

$107,997

$42,048

$324,233

$301,940

$187,203

$42,048

$531,191

NOTES: F = Fair G = Good VG = Very Good

Table 12 presents a more detailed discussion of the relative effectiveness of each alternative.

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TABLE 12 SUMMAR Y OF GARIBALD I WAST E ROCK EE/CA ALTERNATIVES - Alternative

Alternative A — Surfac e Water

a nd Portal Flow Diversion

Alternative B — Surface Water, Portal Flow , and Shallow Alluvial Groundwater Diversion

Alternative C - Surface Water, Portal Flow , and Shallow Alluvial Groundwater Diversion/ Regrading/Simple Cover

Alternative D — Waste Rock Removal

Effectivenes s

Reduces 2 of 4 potential flo w components through the waste rock (surfac e run-on and

portal flow ) Reduces leachin g and erosional releases associated with surface run-on and portal flo w Surfac e erosion of waste rock pil e from direct precipitatio n on the pil e would continue

(approximatel y 6.1 tons/acre/year ) Infiltration (1.4 inches/year) through the waste rock pil e from direct precipitatio n on the pil e

would continue

Improves erosional stability of the diversion channels

Surfac e stabilit y factor of safet y greater than 1

Reduces 3 of 4 potential flo w components through the waste rock (surface run-on, portal

flow , an d groundwater) Reduces leachin g and erosional releases associated with surface run-on, portal flow , and

groundwater

Surfac e erosion of waste rock pil e from direct precipitatio n on the pil e would continue

(approximatel y 6.1 tons/acre/year) Infiltration (1.4 inches/year) through the waste rock pil e from direct precipitatio n on the pil e

would continue

Improve s erosional stabilit y of the diversion channels Surfac e stabilit y factor of safet y greater than 1 Reduces 4 of 4 potential flo w components through the waste rock (surfac e run-on, portal

flow , groundwater, and direct precipitatio n on the pile) Reduces leachin g and erosional releases associated with surface run-on, portal flow ,

groundwater, and direct precipitatio n on the pil e Reduces surface erosion of waste rock pile to approximatel y 1 .0 ton/acre/year

Infiltration through the waste rock pil e from direct precipitatio n on the pil e would be

decreased to approximatel y 0.8 inches/year

Improve s erosional stabilit y of the diversion channels

Improve s surface stabilit y of waste rock pil e to factor of safet y of 2.0 under pseudostatic

condition s and greater than 2.0 under drained condition s

Eliminates 4 of 4 potential flo w components through the waste rock (surfac e run-on, portal

flow , groundwater, and direct precipitation on the pile) by removing the waste rock

Eliminates leachin g and erosional releases associated with surface run-on, portal flow ,

groundwater, and direct precipitatio n on the pil e Eliminates surface erosion of waste rock pile

Eliminate s infiltratio n through the waste rock pil e from direct precipitatio n on the pil e

Flo w from Garibald i portal would continue to flo w i n Uppe r California Gulch

Relocated waste rock would require remediation under OU-10 FS activities

Total Estimated Cost

$175,615

$208,039

$324,233

$531,191
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6 .0 RECOMMENDE D REMOVAL ACTION ALTERNATIV E

Based on the individual analysis of alternatives presented in Section 4.0 and the comparative

analysis presented in Section 5.0, Alternative B is recommended for implementation. A

description of Alternative B and the rationale for its selection are provided below.

6 .1 DESCRIPTION OF ALTERNATIVE B

Alternative B entails the diversion of stream flow (including portal flow ) around the waste rock

by the reconstruction of existing channels and the construction of new channels to prevent runon to and/or infiltration through the waste rock. It also involves the diversion of shallow

alluvial groundwater flo w around the waste rock by construction of groundwater interceptor

trenches. Alternative B is portrayed in Drawing 3.

Under Alternative B, 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. 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 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 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 flow around the pile to the natural stream bed. Diversion ditch

4 would also convey flow 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 road. 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.

The diversion ditches would be designed to safely convey the peak discharge from the 100-year,

24-hour event. The methodology and assumptions used in calculating runoff and model outputs

are included in Appendix B, HEC-1 Model. The ditch design schedule is presented on Drawing

3.

As shown on Drawing 3, all diversion ditches would be trapezoidal ditches with 2-foot bottoms

and 2H:1V side slopes. To help reduce infiltration , Diversion Ditches 2 and 4 would be lined

with concrete. Ditches which do not cross and/or are not adjacent to the pile will not be lined

with concrete. Diversion Ditch 1 would be grass-lined and Diversion Ditch 3 would be lined

with riprap.

Under this alternative, the access road to the Garibaldi Mine Site would require improvement

for use by heavy equipment and the hauling of materials to the site. Approximatel y 500 feet

of the access road would be improved by minor regrading and blading. Culverts would be

replaced, as shown on Drawing 3.

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Under Alternative B, two ground-water 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 and the groundwater interceptor trench for the northern stream channel

would divert flow 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 (HDPE) liner. A filter fabric would

be installed around the clean gravel to reduce siltaton and clogging. A perforated polyvinyl

chloride (PVC) pipe would be placed in the bottom of the trench. The 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.

Best management practices (BMPs) would be utilized during all construction activities at the 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 site. In addition,

dust control, (including use of a water truck) would be practiced during construction.

6 .2 RATIONALE FOR SELECTION OF ALTERNATIVE B

6.2.1 Effectivenes s

Alternative B received a "good" rating in terms of overall protection of human health and

environment, compliance with ARARs, long-term effectiveness, short-term effectiveness, and

reduction of toxicity, mobility, and volume. Alternative B minimizes the contact of the three

identified water components at the Garibaldi Mine Site (surface water run-on, portal flow , and

shallow alluvial groundwater) with the waste rock source material.

Alternative B is considered effective for the followin g reasons:

• Reduces 3 of 4 potential flow components through the waste rock (surface run-on,

portal flow and shallow alluvial groundwater)

• Reduces leaching associated with surface run-on, portal flow and shallow alluvial

groundwater

• Reduces erosional releases associated with surface run-on

• Improves erosional stability of the diversion channels

Run-on is considered a fairly major flow component at the Garibaldi site since the drainage area

above Garibaldi is relatively large (211 acres). Since infiltration from direct precipitation on

the pile would not be reduced by this alternative, it is considered slightly less effective than Alternative C. The reduced costs of this alternative, however, justif y the minimal difference in

effectiveness of the two alternatives. While Alternative D is considered to be the most effective

of the alternatives analyzed, extremely high costs and administrative concerns do not warrant

the implementation of this alternative.

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6.2.2 Implementabilit y

Alternative B is considered to be implementable in terms of the technical feasibility ,

administrative feasibility , availability of services and materials, anticipated agency acceptance, and

anticipated community acceptance.

6.2.3 Cost

Total costs for Alternative B are estimated at $208,039, and include $113,431 for direct capital

costs, $70,327 for indirect capital costs, and $24,281 for post removal site control costs (present

worth).

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Dames and Moore, 1986. Stabilit y and Reclamation Evaluation of Abandoned Tailings Ponds Leadville Unit, Leadville, Colorado.

Emmons, S.F., J.D. Irving, and G.F. Laughlin, 1927. Geology and Ore Deposits of the Leadville Mining District, Colorado. U.S. Geological Survey Professional Paper 148.

Haan, C.T., Barfield, BJ. and Hayes, J.C. Design Hydrolog y and Sedimentolog y for Smal l Catchments. Academic Press, San Diego, CA. 588 p.

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Mortorano, Marilyn A. and David G. Killan . 1990. Addendum to Yak Tunnel Remedial Action Historic Resources Survey, Lake County, Colorado. On file at the State Historic Preservation Office, Denver.

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Tweto, O., 1970. Leadvilie District, Colorado. In, MacDiarmid, R.A., ed., Ore Deposits of the United States . U.S. Geological Survey. Washington, D.C. pgs 681-705.

U.S. Army Corps of Engineers (COE), 1991. HEC-1 Flood Hydrograph Package. Hydrologic

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U.S. Department of Agriculture - Soi l Conservation Service (SCS), 1980. Procedures for Determining Peak Flows in Colorado. Technical Release No. 55.

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U.S. Environmental Protection Agency (EPA), 1987a. Phase I Remedial Investigation Report, California Gulch, Leadvilie, Colorado.

U.S. Environmental Protection Agency (EPA), 1987b. Remedial Action Costing Procedures Manual, Offic e of Solid Waste and Emergency Response, Washington, D.C., EPA Contract 68-03-3113, EPA\600\8-87\049, October.

U.S. Environmental Protection Agency (EPA), 1993a. Final Screening Feasibilit y Stud y for Remedial Alternatives at the California Gulch NPL Site. Leadvilie, CO. September.

U.S. Environmental Protection Agency (EPA), 1993b. Guidance on Conducting Non-Time- Critical Removal Actions under CERCLA. Offic e of Emergency and Remedial Response, U.S. Environmental Protection Agency, Washington, DC 20460. August.

U.S. Environmental Protection Agency (EPA), 1994. Acid Mine Drainage Prediction.

Warner, R.C., and Schwab, P.J., 1992. SEDCAD+ Version 3 Training Manual. Civil Software Design, Ames, IA. Water, Waste and Land, (WWL) 1990. California Gulch Hydrologic Investigation Report. Report prepared for Resurrection Mining Company.

H:\664\EECA\GARBALD.FNL

07/27/95 4:01pm W51/cmc
July 27, 1995_________________________________FINAL * EE/CA Garibaldi Mine Site » 53

Weston, R.F., Inc., 1994. Draft Final Baseline Aquatic Ecological Risk Assessment, California Gulch, Leadville, Colorado.

Woodward Clyde Consultants, (WCC) , 1990. Site Improvements for: Garibaldi Workings; North Mike Workings; Oregon Gulch Tailin g Pond; Starr Ditch.

Woodward Clyde Consultants, Inc. (WCC) , 1993. Hydrogeologic Remedial Investigation Report, Draft , California Gulch Site , Leadville, Colorado.

Woodward Clyde Consultants, Inc. (WCC) , 1993a. Terrestrial Ecosystem Evaluation Report, Draft , California Gulch Site , Leadville, Colorado.

Woodward Clyde Consultants, Inc. (WCC) , 1993 b. Surface Water Remedial Investigation Report, Draft , California Gulch Site , Leadville, Colorado.

Woodward Clyde Consultants, Inc. (WCC) , 1994. Final Mine Waste Piles Remedial Investigation Report.

H:\664\EECA\GARJBALD.FNL

07/27/95 4:01pm WPSl/cm c
July 27, 1995 FINAL * EE/CA Garibaldi Mine Site * Drawings

FIGURES/DRAWING S

HA664\EECA\GARBALD.FNL

07/27/95 4:01pm WP51/cmc
O R A D O

CALIFORNIA GULCH SUPERFUND SITE

NOT TO SCALE

Project No.:

664-0 100

File:

RESWLOC.DWG

/Jrx'U/ n Lly : J.RAY

l)ra:nrn By: K.CONRATH

RESURRECTIO N MININ G COMPAN Y O N E UNITE D BAN K CENTE R 1700 LINCOL N STREE T DENVER , COLORAD O 80203

•Sr.nlv:

N/A

Date:

JULY 1995

FIGURE 1

CALIFORNIA GULCH SITE

GENERAL LOCATION
c

..- PROPOSED \ HAUL ROUTE (Alternativ e D )

GARIBALDI MINE SITE (Refer T o Drawin g 1 For Details )

SCALE

0 2,500' 5,000'

SCALE r = 5.000'

LEGEND

N OPERABL E UNIT 4

CGI G SURFAC E WATE R MONITORIN G LOCATIO N

Project No.:

664-O10O

File:

OU-AREA4.DWG

Design By: J.RAY

Drawn By: T.LEIDICH

RESURRECTIO N MININ G COMPAN Y O N E UNITE D BAN K CENTE R 1700 LINCOL N STREE T DENVER , COLORADO 60203

Scale:

1" .- 5000' Date:

JUL Y 1995

FIGURE 2

GARIBALDI MINE SITE EE/CA

OPERABLE UNIT 4
//- w

 V\ \ \ \\ \ \

NOTE : CG-1 G Located 0 Uppe r California Gulch & , Lak e Count y Road 2 (Show n O n Figur e 2 )

LEGEND

DIVERSIO N DITC H

LIMIT OF WAST E ROCK

CULVER T

PORTA L

ACCES S ROAD

FLOW DIRECTION

SURFAC E WATE R MONITORIN G LOCATIO N

GROUNDWATE R WEL L

N o .

kG M- I

iGMWI W

SCAL E

5 0 0 50 100

CONTOU R INTERVA L 5 F l .

ISSUE D FO R FINA L REPORT

ISSUE D FO R DRAF T REPOR T

ISSUE D FO R PRELIMINAR Y DRAF T

UPDATE/REVISE D

DRAF T

REVISIO N

SCALE : SEE BAR SCALE

DESIG N BY : T.LEID/CH

DRAWN BY : T.LEIDICH

CHEC K BY : J.RAY

PROJEC T No .

664-3200

FIL E NAME : GBEXIST.DWC

DAT E

M G M JM R

BY CHK D

CALIFORNIA GULCH SITE

PROJECT : Garibaldi Mine Site

DRAWIN G TITLE : GARIBALDI MINE SITE

EXISTING CONDITIONS

RESURRECTIO N MININ G COMPAN Y O N E UNITE D BAN K CENTE R

170 0 LINCOL N STREE T DENVER . COLORAD O 80203

SHEET: 1 OF 1

DRAWIN G No. : REV .

4
\

FREEBOARD = o.s

1

LEGEND

TYPICAL UNLINED CHANNEL

DIVERSIO N DITC H

LIMIT OF WAST E ROCK

CULVER T

PORTA L

ACCES S ROAD

FLOW DIRECTIO N

ENERG Y DISSIPATO R

-0.33 FREEBOAR D = 0.3 CONCRET E

CONCRETE LINED CHANNEL

SCAL E

5 0 0 50 100

CONTOU R INTERVA L 5 F t .

-1.5 x D50 DIVERSION DITCH SCHEDULE

DITC H

1

2

3

4 UPPE R

4 LOWE R

PEAK DISCHARG E

(CFS )

0.4

23.0

11.0

39.0

62.0

SID E SLOP E

2Hi1V

2H:1V

2H:1V

2H:1V

2H:1V

CHANNE L SLOP E

( %)

2

2

17

16

11

VELOCIT Y

(FPS )

1.4

8.7

7.4

21.4

21.3

FLOW DEPT H (FT )

0.1

0.8

0.5

0.6

0.8

LINE R TYP E

GRAS S

CONCRET E

RIPRAP D50=6"

CONCRET E

CONCRET E

i-FREEBOAR D = 0.3

1 r——— — RIPRA P

TYPICAL RIPRAP LINED CHANNEL DRAWIN G No . WHER E • DETAIL/SECTIO N I S REFERENCE D

-DETAIL/SECTIO N NUMBE R

DETAIL/SJECTIO N I S SHOW N

7K

N o .

ISSUE D FO R FINA L REPOR T

ISSUE D FO R DRAF T REPOR T

ISSUE D FO R PRELIMINAR Y DRAF T

UPDATE/REVISE D

REVISIO N

SCALE :

see BAR SCALE DESIGN BY : T.LEIDICH

DRAWN BY : T.LBD/CH

CHEC K BY : J.RAY PROJEC T No .

664-3200

FIL E NAME : GBAL TIDWC

DAT E

T E L J M R

B Y CHK D

CALIFORNIA GULCH SITE

PROJECT : Garibaldi Mine Site

DRAWIN G TITLE : GARIBALDI MINE SITE AL TERNA TIVE A

RESURRECTIO N MININ G COMPAN Y O N E UNITE D BAN K CENTE R

1700 LINCOL N STREE T DENVER , COLORAD O 80203

SHEET: 1 OF *

DRAWIN G No.:

2

REV .

4
DIVERSION DITCH SCHEDULE

DITC H

1

2

3

4 UPPE R

4 LOWE R

PEAK DISCHARG E

(CFS )

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

(54 )

2

2

17

16

11

VELOCIT Y

(FPS )

1.4

8.7

7.4

21.4

21.3

FLOW DEPT H (FT )

0.1

0.8

0.5

0.6

0.8

LINE R

TYP E

GRAS S

CONCRET E

RIPRAP D50=6"

CONCRET E

CONCRET E

FREEBOAR D = 0.3RIPRA P

TYPICAL RIPRAP LINED CHANNEL

LEGEND

CLEAN GRAVE L -

HOP E LINER -

DITC H

DIVERSIO N DITC H

LIMIT OF WAST E ROCK

CULVER T

PORTA L

ACCES S ROAD

GROUNDWATE R TRENC H

PIP E

FLOW DIRECTION

ENERG Y DISSIPATO R

SLOTTE D PV C PIP E

BEDROCK

Note: (Intercepto r Trench Wil l B e Keyed Into Bedrock A s Condition s Allow )

^\GROUNDWATER INTERCEPTOR TRENCH v3 31

L FREEBOAR D = 0.3

• 2' - TYPICAL UNLINED CHA NNEL

DRAWIN G No . WHER E • DETAIL/SECTIO N I S REFERENCE D

CONTOU R INTERVA L 5 F l .

-DETAIL/SECTIO N NUMBE R

DRAWIN G No . WHER E DETAIL/SECTIO N I S SHOW N

FREEBOAR D = 0.3 CONCRETE -

TYPICAL CONCRETE LINED CHANNEL

ZL\

N o .

ISSUE D FO R FINA L REPORT

ISSUE D FO R DRAF T REPORT

ISSUE D FO R PRELIMINAR Y DRAF T

UPDATE/REVISE D

REVISIO N

SCALE : SEE BAR SCALE

DESIGN BY : T.LSDICH

DRAWN BY : T.LEDICH

CHEC K BY : J.RAY PROJEC T No .

664-3200

FIL E NAME : GBAL T2.DWG

DAT E BY CHK D

CALIFORNIA GULCH SITE

PROJECT : Garibaldi Mine Site

DRAWIN G TITLE ; GARIBALDI MINE SITE AL TERNA TIVE B

RESURRECTIO N MININ G COMPAN Y O N E UNITE D BAN K CENTE R 1700 LINCOL N STREE T DENVER . COLORAD O 80203

SHEET: t OF 7

DRAWIN G No. :

3

REV .

4
1 8" OF LOW PERMEABILIT Y MATERIAL LEGEND

TYPICAL SIMPLE COVER

CLEAN COBBLE -

HOP E LINER -

DITC H

DIVERSIO N DITC H

LIMI T O F WAST E ROCK

CULVER T

PORTA L

ACCES S ROAD

GROUNDWATE R TRENC H

PIP E

REGRADE D TOPOGRAPH Y

FLOW DIRECTION

ENERG Y DISSIPATO R

• 1H2SC.'^'^ J V^^E 1SLOTTE D PV C PIP E

Note: (Intercepto r Trench Wil l B e Keyed Into Bledrock A s Condition s Allow )

^GROUNDWATER INTERCEPTER TRENCH

FREEBOAR D = 0.3

CONTOU R INTERVA L 5 F t .

TYPICAL UNLINED. CH/-NNEL

DRAWIN G NO . WHER E • DETAIL/SECTIO N I S REFERENCE D

-DETAIL/SECTIO N NUMBE R

DRAWIN G No . WHER E DETAIL/SECTIO N I S SHOW N

MATERIA L MOVEMENT - 3100 C Y AREA OF DISTURBANCE - 1.6 ACRE S

DIVERSION DITCH SCHEDULE

DITC H

1

2

3

4 UPPE R

4 LOWE R

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

(%)

2

2

M

16

11

VELOCIT Y

(FPS )

1.4

8.7

7.4

21.4

21.3

FLOW DEPT H (FT )

0.1

0.8

0.5

0.6

0.8

LINE R TYP E

GRAS S

CONCRET E

RIPRAP D50=6"

CONCRET E

CONCRET E

FREEBOAR D = 0.3 RIPRA P FREEBOAR D = 0.3 CONCRETE -

TYPICAL RIPRAP LINED CHANNEL ^2\TYPICAL CONCRETE LINED CHANNEL

7\

7KZ\ N o .

ISSUE D FO R FINA L REPOR T

ISSUE D FO R DRAF T REPORT

ISSUE D FO R PRELIMINAR Y DRAF T

UPDATE/REVISE D

DRAF T

REVISIO N

SCALE :

see BAR SCALE

DESIGN BY : T.LEIDICH

DRAWN BY : T.LEIDICH

CHEC K BY : J.RAY PROJEC T No .

FIL E NAME : GBAL T3.DWG

DAT E B Y CHK D

CALIFORNIA GULCH SITE

PROJECT : Garibaldi Mine Site

DRAWIN G TITLE : GARIBALDI MINE SITE ALTERNATIVE C

RESURRECTIO N MININ G COMPAN Y O N E UNITE D BAN K CENTE R

1700 LINCOL N STREE T DENVER . COLORAD O 80203

SHEET: 1 OF 1

DRAWIN G No. :

4

REV .

4
r

NOTE : VOLUME OF WAST E ROCK REMOVED 27,900 C Y

LEGEND

RE-ESTABLISHED CHANNEL — • • — •

LIMI T OF WAST E ROCK — — - -

CULVERT >—— < PORTA L >——— — ACCES S ROAD ~ ~ ~

PRE-MIN E TOPOGRAPH Y ——n«s-

FLOW DIRECTION

SCALE

0_______SO

CONTOU

^^^R INTERVA Z L 5

7\

No.

ISSUED FOR FINAL REPORT

ISSUED FOR DRAF T REPORT

ISSUED FOR PRELIMINARY DRAF T

UPDATE/REVISED

DRAF T

REVISION

SCALE : SEE BAR SCALE

DESIGN BY :

r.LBOICH

DRAWN BY : T.LEID/CH

CHECK BY : J.RAY PROJEC T No . BBi-3200

FILE NAME : GBAL TJ.DWG

7/95 MGM JMR

DAT E BY CHK D

CALIFORNIA GULCH SITE

PROJECT : Garibaldi Min

e Site

DRAWING TITLE : GARIBALDI MINE SITE ALTERNATIVE D

RESURRECTION MINING COMPAN Y O N E UNITE D BAN K CENTE R

1700 LINCOLN STREET DENVER . COLORAD O 80203

SHEET : 1 OF 1 DRAWIN G No. : 5

REV . 4
July 27, 1995 FINAL * EE/CA Garibaldi Mine Site * Attachments

ATTACHMENT S

H:\664\EECA\GARIBALD.FNL

07/27/95 5:36pm WP51/cmc
ATTACHMENT 1

RESPONS E T O PUBLI C COMMENT S

Responses to comments on the Draft Engineering Evaluation and Cost Analysi s for Garibaldi Mine Site Withi n Upper California Gulch Operable Unit 4 (EE/CA) are presented on the

followin g pages. The EE/CA was submitted to the EPA and the Colorado Department of Public Health and Environment (CDPHE) on June 2, 1995, and was available for public review

and comment from Jun e 5, 1995 to July 7, 1995.

Comments on the EE/CA were received from the CDPHE and the Bureau of Reclamation on Jul y 11, 1995 and from the Lake County Board of County Commissioners on Jul y 13, 1995.

H:\664\gmssub.Itr

07/27/95 4:48pm WP51/cmc
United States Department of the Interior

- BUREAU OF RECLAMATION R*olMUktto» Sctvit* Ovotor P.O. But 85007

6 T, Dcawr F«d«r*l Ctottr

, Cctendo SCOS-COO?

ENV-3.00

JUN30 199S

Environmental Protection Agenc Attention: MS. Denise Link Reroedial Project Manager Region VTII, Suite 500

999 isch street Denver CO 80202

Dear Ms. Link;

Thank you for the opportunity to review the Pi-aft Ena i

t Analvsijs for Garibaldi Miae Site Within

(EE/CA) prepared by Shepherd-ltiller Inc . , and TerraMatrix . I have the lollowing

conmetnt:

Section 4. S.I . 3. Refracting /Simpl e Covwi . This auction

references Drawing 4 and states that 3K:1V slopes are

shown. I do not find, thia 3:1 elope clearly indicated

on the drawing, the slopes within the proposed channels

appear to retain the 2H:1V slopes from previous

drawings .

Section 4.6.1. Description of Alternative D. Thi s

alternative would require the conduct of additional

cultural resource inventory and evaluation for the road

improvements and the new road construction. This is not

identified within the discussion. Tfce discussion should LuwiuUe a. section relative to this worfc and a discussion

that increased costs will be added per the cultural

resource requirements, if new road construction will

require a roadway to accommodate two-way traffic , rather

than just one traffi c direction, if additional turnouts

or staging areas will be involved, these will require

cultural resource work. Compliance with Section 106 of

the National Historic Preservation Act will be required

for improvements and/or new construction. No drawing of

the proposed route is included. If Shepherd-Miller and TerraMatrix have been able to state that construction of

a new haul road would "provide a shorter haul route.

1

 I

assume a proposed route has been identified. Thi s

should be included.
Section 4.6.2.2. Administrative Feasibility , it would

bo helpful to include a statement detailin g that for Alternative D, additional administrative issues

pertinent to cultural resources will be required. Specifically , planning for Section 106 compliance.

section 6.1. Page 48. Spellin g Error: Condition is misspelled.

Appendix F, F.2.4 Cultural Resources. The firs t

paragraph should be corrected to state the removal

action is an "undertaking under the NHPA." The

statement: "EPA has however, made a preliminary

determination that resources within the area potentiall y

effected by the proposed removal action are not eligible

for inclusion in the National Register of Historic Places.8

 should be reworded. The letter the Colorado State Historic Preservation Officer (SHPO) provided in which the SHPO determined the Garibaldi Mine Site 'not

individually eligible, ... not within the existing Leadville Historic District and ... not contribute to

district expansion does not clarif y if A3ARCO was

requested to submit this material to the SHPO for EPA. However, as SPA does not wish to dispute the)

determination made by the SHPO/ EPA nay now utilize this

determination to conclude the Section 106 process, for

this individual site. The determination is final not

preliminary.

in the next paragraph the Historical and Archaeological Preservation Act of 1974 is incorrectly identified. The

word Data needs to be deleted.

F.2.6. Clean water Act (Section 404). is the •National permit discussed here a Section 404 Permit or

a Nationwide Permit?

Table F.I. Archaeological and Historical Preservation Act should be correctly identified. Delete Data from

the title. The Historic Sites Act of 1935 is included within this table but no discussion of this is present

in the text.

Appendix G. Coat Estimates. All cost estimates have

included Cultural Resources, identified as a lump sum

payment* amount ($10,000) and source as previous

projects . For Alternative A, no historic properties are

involved in the on-site construction for ditches 1-4. Any cultural resource work would only be necessity for

the 500 feet of improvement, regrading and blading, to

the existing road. The amount ($10,000) allocated here
for cultural resource work appears to be excessive, in

fact , if road improvements are confined to the rereading

and blading with no increase in roadway width, then

cultural resource work may be eliminated altogether. The initial construction of the road may have destroyed

the potential for significan t cultural properties to be

present.

Again for Alternative B, the same levels of costs are

identified- for cultural resources. Review of Alternative B indicates that on-siLe work will be

confined to areas previously included in cultural

resource inventory and evaluation. Road improvements

are anticipated Lo be the same as Alternative A. My

previous comment relative to the amount ($10,000 )

applies here also,

Alternative C nay also be included in my comment on the

costs.

Alternative D is exactly the same as the others, $10,000

is targeted for cultural resources work. Alternative D will require additional cultural resource work,

reportage, and additional time for EPA Lo initiate and

conclude the Section 106 process. Does the amount

indicated here provide Cor the conduct of this new work

or has the amount allocated simply been carried forward with little thought Cor actual expenses?

I have one correction to comment provided Cor the BE/CA for

the Colorado Zinc-Lead Tailin g Area, letter dated 23 June 1995. in section 1.4, my sentence reading: 'The discussion

here needs to be revised to indicate the removal action for

the tailings will only effec t site 5LK845;" should be

reworded to: The discussion here needs to be revised to

indicate the removal action will only effec t Feature D of

site 5LK845.

I look forward to continuing to work with you and Resurrection Mining Company aa this project moves forward. Should you have questions regarding these conraontc, please

call me at 236-2722 extension 341.

Sincerely,

&- Patricia McCcy O Cultural Resource Sp«ci«liau Technical Service Center
July 24, 1995_______________________________________Comment Responses * OU-4__

BUREAU OF RECLAMATION COMMENTS

1. Comment: Section 4.5.1.3. Regrading/Simple Cover. Thi s section references drawing

4 and states that 3H:1V slopes are shown. I do not fin d this 3:1 slope clearly indicated

on the drawing. The slopes within the proposed channels appear to retain the 2H:1V

slopes from previous drawings.

Response: The drawing will be clarified to indicate a 3:1 slope.

2. Comment: Section 4.6.1. Description of Alternative D. Thi s alternative would require

the conduct of additional cultural resource inventory and evaluation for the road

improvements and the new road construction. Thi s is not identified within the

discussion. The discussion should include a section relative to this work and a discussion

that increased costs will be added per the cultural resource requirements. If new road

construction will require a roadway to accommodate two-way traffic , rather than just one

traffic direction, if additional turnouts or staging areas will be involved, these will require

cultural resource work. Compliance with Section 106 of the National Historic Preservation Act will be required for improvements and/or new construction. No

drawing of the proposed route is included. If Shepherd-Miller and TerraMatrix have

been able to state that construction of a new haul road would "provide a shorter haul

route," I assume a proposed route has been identified. Thi s should be included.

Response: The description of Alternative D will be enhanced to discuss potential

cultural resources requirements associated with the implementation of the alternative. Costs will be updated to include the appropriate level of cultural resources work

anticipated for this alternative. A drawing will be provided indicating the proposed haul

route.

3. Comment: Section 4.6.2.2. Administrative Feasibility . It would be helpful to include

a statement detailin g that for Alternative D, additional administrative issues pertinent to

cultural resources will be required. Specifically , planning for Section 106 compliance.

Response: A statement pertaining to additional administrative issues associated with

cultural resources will be added to this section.

4. Comment: Section 6.1 Page 48. Spellin g Error: Condition is misspelled.

Response: The misspelling will be corrected.

5. Comment: Appendix F, F.2.4. Cultural Resources. The firs t paragraph should be

corrected to state the removal action is an "undertaking under the NHPA." The

statement: "EPA has however, made a preliminary determination that resources within

the area potentiall y effected by the proposed removal action are not eligible for inclusion

in the National Register of Historic Places." should be reworded. The letter the Colorado State Historic Preservation Officer (SHPO) provided in which the SHPO

determined the Garibaldi Mine Site "not individually eligible,... not within the existing Leadville Historic District and...not contribute to district expansion" does not clarify if ASARCO was requested to submit this material to the SHPO for EPA. However, as

EPA does not wish to dispute the determination made by the SHPO, EPA may not

H:\664\COMMENTS-RSP

07/27/95 4:25pm WP51/cmc
July 24, 1995______________________________________Comment Responses * OU-4

utilize this determination to conclude the Section 106 process, for this individual site. T he determination is final not preliminary.

In the next paragraph the Historical and Archaeological Preservation Act of 1974 is

incorrectly identified. The work Data needs to be deleted.

Response: Appendix F, Section F.2.4 will be revised as suggested.

6. Comment: F.2.6. Clean Water Act (Section 404). Is the "National" permit discussed

here a Section 404 Permit or a Nationwide Permit?

Response: The word "National" will be replaced with the work "Nationwide".

7. Comment: Table F.I. Archaeological and Historical Preservation Act should be

correctly identified. Delete Data from the title. The Historic Site s Act of 1935 is

included within this table but no discussion of this is present in the text.

Response: "Data" will be deleted from the title of the Archaeological and Historical Preservation Act. The Historic Sites Act of 1935 will be deleted from the table.

8. Comment: Appendix G. Cost Estimates. All cost estimates have included Cultural Resources, identified as a lump sum payment, amount ($10,000) and source as previous

projects . For Alternative A, no historic properties are involved in the on-site

construction for ditches 1-4. Any cultural resource work would only be necessary for

the 500 feet of improvement, regrading and blading, to the existing road. The amount

($10,000) allocated here for cultural resource work appears to be excessive. In fact, if

road improvements are confined to the regrading and blading with no increase in

roadway width, then cultural resource work may be eliminated altogether. The initial

construction of the road may have destroyed the potential for significant cultural

properties to be present.

Again for Alternative B, the same levels of costs are identified for cultural resources. Review of Alternative B indicates that on-site work will be confined to areas previously

included in cultural resource inventory and evaluation. Road improvements are

anticipated to be the same as Alternative A. My previous comment relative to the

amount ($10,000) applies here also.

Alternative C may also be included in my comment on the costs.

Alternative D is exactly the same as the others, $10,000 is targeted for cultural resources

work. Alternative D will require additional cultural resource work, reportage, and

additional time for EPA to initiate and conclude the Section 106 process. Does the

amount indicated here provide for the conduct of this new work or has the amount

allocated simply been carried forward with little thought for actual expenses?

Response: The costs will be adjusted to reflect the relative differences in the scope of

the cultural resources activities under each Alternative.

H:\664\COMMENTS.RSP

07/27/95 4:25pm WP51/cmc
STATE OF COLORADO

Rwy K.H.rrt, O~«-i i** •• ^ Jfl! ^ » -

r, Acting ExecuCv* Dtre«fer - / Ptf ?.

 Av<

 '

'''' 4300U*nyu««kL>r>. 222 5. «h *nm town 232 Dcn«r. Colorado W222-1530 ^JgjdSoM^do 91 501-2766. ^ Coloiado Pt»fl« 003) 692-3300

nut ciwifofuncot

My 6, 1995

Ms. Denise Link Remedial Project Maoager-^HM-SR California Gulch Site U.S. EPA, Region Vin

999 18th Street, Suite 5UO Denver, Colorado 80202-2405

RE: CDPHE Comments on tbe Following Resurrection Mining Company EE/CAs:

-Draft EE/CA for tb» Garibaldi Mine Site is Upper California Chilct (OU-4);

-Draft EE/CA for the Colorado Zinc-Lead Tailing Area

in Lower California Gulch (OU-8).

Dear Ms. Link:

Attached are the CDPHE comments for the above-referenced EE/CAs. These comments

are in addition to those submitted to EPA on May 26,1995, pertaining to tbe Preliminary Draft versions of the ED/CA». Filial disposition of Ac EE/CA ARARs Usue*, and th»

comments regarding such, will be forthcoming subsequent to further discussion by EPA and

the CDPHE. If you have any questions, please don't hesitate in calling me at 692-3382.

Sincerely. /\ UUUU«s — Russ Alien Hazardous Materials and Waste Management Division

cc: Gary Herbert, CBRCLA-AOO Don Deere, RMC
CDPHE COMMENTS: DRAFT EE/CA. GARIBALDI MINE SITE UPPER CALIFORNIA GULCH, OU-4 JUNE 1995

(TERRA MATRIX & SHEPHERD MILLER FOR RESURRECTION MINING)

GENERAL COMMENTS1. The effectiveness of this EE/CA, in satisfactorily achieving final sitewide

water quality AJRARs (when addressed ic OU-12), cannot be adequately

evaluated until all FS remedial action performance criteria, as presented in

tne Ressurection WAMP (i.e.,surface erosional stability, slope stability, flow

capacity and stability, surface water and ground water loading reduction,

terrestrial ecusystcm exposure, and non-residential soils), have been

quontotatively assessed. Accordingly, the CDPHE concur? with Resurrection's

assertion (page I, last paragraph; and page 2. fust paragraph) that clean-up

conducted under this ht/CA is not intended to be a final action but rather

an interim action that is intended to contribute to the efficient performance

of future remedial actions for OU-4. The Record of Dtxbiuu (ROD) for OU-4 may determine that further clean-up actions will be required by Resurrection Mining (at the Garibaldi Mine Site) pursuant to the Consent Decree in settlement of Civil Action No. 86-C-1675 (consolidated with Civil Action No. 83-C-2388).

2. CDPIIE previously commmented (May 25,1995 correspondence to EPA) that

the 2:1 side slopes on the riprap lined channels were too steep and that they

should be no steeper than 3:1. The Draft EE/CA continues to show side

dopes at 2:1, accordingly, please demonstrate the stability and provide

rationale for the use of these steep side slopes.

3. The EE/CA should be expanded to demonstrate how die effectiveness of this

interim action will be evaluated.
July 24, 1995________________________________________Comment Responses * OU-4

COLORADO DEPARTMENT OF PUBLI C HEALTH AND ENVIRONMENT COMMENT S

1. Comment: The effectivenes s of this EE/CA, in satisfactorily achieving final site-wide

water quality ARARs (when addressed in OU-12), cannot be adequately evaluated until

a ll FS remedial action performance criteria, as presented in the Resurrection WAMP (i.e..,

surface erosional stability , slope stability , flo w capacity and stability , surface water and

ground water loading reduction, terrestrial ecosystem exposure, and non-residential soils),

have been quantitatively assessed. Accordingly, the CDPHE concurs with Resurrection' s

assertion (page 1, last paragraph; and page 2, firs t paragraph) that clean-up conducted

under this EE/CA is not intended to be a final action but rather an interim action that

is intended to contribute the efficien t performance of future remedial actions for OU-4. T he Record of Decision (ROD) for OU-4 may determine that further clean-up actions

will be required by Resurrection Mining (at the Garibaldi Mine Site) pursuant to the Consent Decree in settlement of Civil Action No. 86-C-1675 (consolidated with Civil Action No. 83-C-2388).

Response: Thi s comment requires no response.

2. Comment: CDPHE previously commented (May 26, 1995 correspondence to EPA) that

-the 2:1 side slopes on the riprap lined channels were too steep and that they should be

no steeper than 3:1. The Draft EE/CA continues to show side slopes at 2:1, accordingly,

please demonstrate the stabilit y and provide rationale for the sue of these steep side

slopes.

Response: As discussed in the comment responses to your May 26, 1995 correspondence

with EPA, due to area constraints, the side-slopes have been designed at a 2:1 slope. A

detailed survey of the Garibaldi site is presently underway for use during remedial design

activities. If sufficien t area is available, the remedial design will reflect a 3:1 slope, as

suggested. Otherwise, stability of the 2:1 side slopes will be demonstrated.

3. Comment: The EE/CA should be expanded to demonstrate how the effectivenes s of

this interim action will be evaluated.

0

 Response: Per the Consent Decree and WAMP, no water quality standards for this

interim action are permitted. As discussed in the comment responses to your May 26,

1995 correspondence with EPA, Pre-EE/CA water quality is presently being monitored

at the Garibaldi site. Post-EE/CA water quality will be monitored at the same sites

followin g procedures set forth in the Work Plan for a Water and Aquatic Biological Sampling Program for Upper Arkansas River/California Gulch. Flow and water quality monitoring will continue after implementation of the Removal Action in order to assess

the effectiveness of the Removal Action. Particular emphasis will be placed upon flow

at the toe of the pile.

H:\664\COMMENTS.RSP

07/27/95 4:25pm WPSl/cm c
BOARD OP

cocmnr

July 7,1995

Demise Link U.S. Environmental Protection Agency

8HWM-SR

999 Eighteenth Street, Suite 500 Denver, Colorado 80202-2466

Re: Draft Engineering Evaluation/Cost Analysis For Hie Garibaldi Mine Site

Dear Ms. Unk;

We appreciate the opportunity to comment on the Draft Engineering Kvaluation/Cosf Analysis for The Garibaldi Mine Site. In general we are in agreement with the Recommended Removal Action, Alternative B. The historical significance of the Garibaldi waste rock, as wall as the other wade rock piles included in die California Gulch Superfund Site, require thai these areas be preserved Alternative B accomplishes

this objective which is important to the heritage and economy of our community.

Vcc: Lake Comity Peal v.

Yours very truly,

fames E. Matting ^P^ Lake County Commissioner

Robert W Lake County

Earl B Lake County

COMMISSIONERS fi. Martin-Chairman. Robert W. CWM? • Eari Boeve • timothy H- Berry-County Attorney

— muni. m*> 4MMMMS • Fax (Tit) 4£e-397S TOTflL P.84
July 24, 1995________________________________________Comment Responses * OU-4

LAK E COUNT Y BOARD OF COUNT Y COMMISSIONER S

1. Comment: We appreciate the opportunit y to comment on the Draft Engineering

Evaluation/Cos t Analysis for the Garibaldi Mine Site. In general we are in agreement

with the Recommended Removal Action, Alternative B. The historical significance of

the Garibaldi waste rock, as well as the other waste rock piles included in the California Gulch Superfun d Site, require that these areas be preserved. Alternative B accomplishes

this objective which is important to the heritage and economy of our community.

Response: Thi s comment requires no response.

H:\664\COMMENTS.RSP

07/27/95 4:38pm WP51/cmc
July 27, 1995 FINAL * EE/CA Garibaldi Mine Site * Appendices

APPENDIX A

STAT E HISTORI C PRESERVATIO N 0TMFIC E LETTE R

H:\664\EECA\GARBALD.FNL

07/27/95 4:01pm WP51/cmc
COLORADO HISTORICAL SOCIET Y

The Colorado History Museum 1300 Broadway Denver. Colorado 80203-2137

August 31, 1990

Glenn Anderson

ASARCO

1019 8th Street , Suite 304 Golden , Colorado 80401

R e: Res-ASARCO Join t Venture Draf t Cultural Resources Report

Dear Mr. Anderson:

We have reviewed draf t information for the above report and have the

followin g comments about the components of this undertaking:

Wel l Site s (#1, *2. #3 and *6) - The information satisfactoril y

documents the lack of historic properties in these locations. Therefore we

anticipate that there will be no effec t on historic properties.

North Mike Workings - It is our opinion that this is a contributing

element of the Adelaide site (5LK709) , which has been determined eligible

for inclusion in the National Register of Historic Places. We fin d that

the nature of the proposed site improvement project will have no effec t on

the qualities of significance of the historic property.

Oregon Gulch Tailings Pond fSUC382 ) - We can find no record of a

determination of eligibility for the Resurrection Hill/Ya k Tunnel Site. However, the Resurrection Sites (5LX700) , which are not in the vicinity of

this tailings pond or the mill site, have been determined eligible. The

pond and the large collection of upright supports would be contributing

elements to the cultural landscape of the proposed boundary expansion of

the Leadville Historic District for their contribution to our understanding

of metal mining processes. The two small metal structures would be noncontributing. It is our determination that the proposed site improvement

project will have no effec t on historic properties.

Garibaldi Workings (SLK80S1 - He find that this property is not

individually eligible, is not within the existing Leadville Historic District and would not contribute to the district expansion. Again, the

nature of the site improvements is such that there will be no effec t on

historic properties.
July 27, 1995 FINAL * EE/CA Garibaldi Mine Site * Appendices

APPENDIX B

HEC-1 MODEL

H:\664\EECA\GARIBALD.FNL

07/27/95 4:01pm WP51/cmc
SURFAC E WATE R SYSTEM DESIG N METHODOLOGIE S AN D ASSUMPTION S

HYDROLOGIC MODELING

Hydrologic modeling was performed to determine the peak runof f flows for design of diversion

channels around the waste rock pile.

HEC-1 Flood Hydrograph Computer Model

Runof f calculations for all alternatives were performed utilizin g the HEC-1 Flood Hydrograph Computer Model developed by U.S. Army Corps of Engineers (1991). HEC-1 is a hydrologic

and hydraulic calculation model designed for use on PC computer systems. The model is

designed to simulate the surface runof f response of a watershed to precipitation by representing

the basin as an interconnected system of hydrologic and hydraulic components. The result of

the modeling process is the computation of streamflow hydrographs at desired locations in the

river basin. A hydrograph is simply a plot of flow peak flow rates as a function of time at a

point in the drainage basin. HEC-1 calculates peak flow rates and runof f volumes via a

numerical modeling technique based on user inputs of a design storm event, (i.e., precipitatio n

frequency data and selection of rainfal l distribution). Hydrographs are developed on a

subwatershed basis with the input of area, lag time, and precipitation loss (i.e., SCS Curve Number which relates drainage to soil type, soil cover, land use, and antecedent moisture

conditions). Routing of hydrographs is accomplished by the kinematic wave method for

overland flo w and the Muskingum method for collector channels.

Input s to the model include:

Precipitation Information Precipitation Losses Hydrograph Response Shape L ag Time Routing Parameters

Input values used in this model are explained below and are shown in the HEC-1 Input included

in Appendix B-l (Alternatives A, B, and C) and Appendix B-2 (Alternative D).

Precipitation Information

T he precipitation information needed includes the amount of precipitation and storm

distribution and duration.

T he Work Area Management Plan (USDC, 1994) specifies that remedial alternatives utilizing

diversion channels and/or reconstructed stream channels located outside of the 500-year

floodplai n of California Gulch must have sufficien t capacity to convey the 100-year, 24-hour and

2-hour storm events.

Based on the NOAA Atlas II - Precipitation Frequency Atlas of the Western United States , Volume m, Colorado (May - October), the precipitation amount used for the Garibaldi Mine Site is:

100-year, 24-hour storm event 2.4 inches
T he SCS determined that the relationship between lag time and the time of concentration can

be calculated using the equation:

tL = 0.6 t

c

where, tL is the lag in hours

t

c

 is the time of concentration in hours

Routing Parameters

Subbasin outflow may be obtained utilizin g overland flow planes, collector channels and a main

channel. Two routing methods were used to route rainfal l runof f through the watershed. The Muskingum routing technique was used to route overland flow, and the kinematic wave method

was used to route lateral inflows and upstream hydrographs through channels.

T he Muskingum routing technique relies on the SCS Uplan d Method. The upland method

calculates the time of concentration for a watershed or watershed segment by summing the flow

time for overland flo w and channel flow. Flow time is a function of land use, length of travel,

and slope.

T he kinematic wave method was used to route lateral inflows and upstream hydrographs

through channels. The kinematic wave parameters used to determine the total hydraulic time

are based on an approximation of Manning's equation. Thi s routing method uses physical

channel properties and the upstream inflow hydrograph. Input data consists of channel length,

channel bed slope, Manning roughness coefficient , and channel cross-section information.

CHANNE L MODEL

T he surface water diversions were sized using Manning' s Equation for open channel flow. The

slope of the ditches were determined from a 1" = 1000 computer generated map.

Q = 1.486 AR%S"

n

where, Q = peak discharge from a storm event (cfs)

n = Manning's roughness coefficien t A = cross sectional area of flow (ft2) R = hydraulic radius (ft) S = channel slope (ft/ft)

A Manning's roughness coefficien t of 0.035 and 0.015 was used for grass lined and concrete

channels respectively (Haan, et al., 1994). According to Abt (1988), a Manning's n for riprap

in steep channels can be approximated by:

i0.159 n = 0.0456 (D50

 S)a

where, n = Manning's roughness coefficien t D

50

 = average riprap diameter (inches) S = channel slope (ft/ft)

A Manning's "n" of 0.041 was calculated for the riprap lined channel.
July 27, 1995 FINAL * EE/CA Garibaldi Mine Site * Appendices

APPENDIX B-1

HEC-1 MODEL ALTERNATIVES A, B, AND C

H:\664\EECA\GARIBALD.FNL

07/27/95 4:01pm WP51/cmc
HEC 1 S/N : 0134300665 HMVersion : 6.33 Data File : c:\hecpack\resurrec\garibald.hc1

*************************************

\^_^/ *

* FLOO D HYDROGRAPH PACKAG E (HEC-1 ) *

* HAY 1991 *

* VERSION 4.0.1E * * *

* RUN DAT E 05/11/1995 TIME 11:35:59*

* *

*****************************************

***************************************

U.S . ARMY CORP S OF ENGINEER S

HYDROLOGI C ENGINEERIN G CENTE R

6 09 SECOND STREET

DAVIS , CALIFORNI A 95616

(916) 756-1104

***************************************

X X XXXXXX X XXXX X

X X X X X

X X X X

XXXXXX X XXX X X

X X X X

X X X X X

X X XXXXXXX XXXXX

XXXX X

X

XX

X

X

X

X

X X X

Ful l Microcomputer Implementatio n

by Haestad Methods , Inc .

37 Brookside Road * Waterbury , Connecticut 06708 * (203) 755-1666

THI S PROGRAM REPLACE S AL L PREVIOU S VERSION S O F HEC-1 KNOUN A S HEC 1 (JAN 73), HEC1GS , HEC1DB , AN D HEC1KW .

T H E DEFINITION S O F VARIABLE S -RTIHP - AN D -RTIOR - HAV E CHANGE D FROM THOS E USE D WITH TH E 1973-STYL E INPU T STRUCTURE . T H E DEFINITION O F -AMSKK - ON RM-CAR D WA S CHANGE D WITH REVISION S DATE D 2 8 SE P 81 . THI S I S TH E FORTRAN? ? VERSION

N EW OPTIONS : DAMBREAK OUTFLO W SUBMERGENC E , SINGL E EVEN T DAMAG E CALCULATION , DSS:WRIT E STAG E FREQUENCY , DSS:REA D TIM E SERIE S A T DESIRE D CALCULATION INTERVA L LOS S RATE:GREEN AN D AMP T INFILTRATION

KINEMATI C WAVE : NE W FINIT E DIFFERENC E ALGORITH M
HEC- 1 INPU T PAG E 2

LIN E ID.......1.......2.......3.......4.......5.......6.......7.......8.......9......10

38 KK ditch4Alpin e Overland Flow Routed to Ditch 4

39 KM route alpin e flo w through woods to ditch #4

40 RM -1 0.119 0.339

41 KK 4woodsDitch 4 Woods Subwatershed Generation

42 KM runof f from woods that drain s to ditch #4

43 BA 0.0717

44 LS 0 60

45 UD 0.145

46 KK 3and4Upper Ditch 4 Flow

47 KM combine ditch 3 flo w with inflow s from ditch 4 subwatersheds

48 HC 3

49 KK 4at2Route Upper Ditch 4 Hydrograph to junctio n with Ditch 2

50 KM route flo w through upper ditch 4 to ditch 2 inflo w

51 RK 220 0.16 0.015 TRAP 2 2

52 KK IwoodsDitch 1 Woods Subwatershed Generatio n

53 KM runof f from woods that drain s to ditch #1

54 BA 0.0073

55 LS 0 60

56 UD 0.072

57 KK loutflRout e Ditch 1 flo w to Ditch 2 inflo w

58 KM route ditch 1 flo w to ditch 2

59 RK 441 0.02 0.035 TRAP 2 2

60 KK 2alpinDitch 2 Alpin e Subwatershed Generation

61 KM runof f from alpin e subwatershed that drains to ditch 2

62 BA 0.0611

63 LS 0 80

64 UD 0.126

65 KK ditch2Alpin e Overland Flow Routed to Ditch #2

66 KM route alpin e flo w through woods to ditch #2

67 RM -1 0.13 0.347

68 KK 2woodsDitch 2 Woods Subwatershed Generation

69 KM runof f from woods that drains to ditch 2

70 BA 0.0473

71 LS 0 60

72 UO 0.077

73 KK 1and2Combine Ditch 1 flo w with Ditch 2 subwatershed inflow s

74 KM combine flo w from ditch 1 with ditch 2 inflow s

75 HC 3

76 KK 2at4Route Combined Ditch 1 and Ditch 2 Flow to Ditch 4

77 KM route flow s from ditch 2 to ditch 4 junctio n

78 RK 225 0.08 0.015 TRAP 2 2
INPU T

N O .

7

18

SCHEMATI C DIAGRAM O F STREAM NETWORK

( V ) ROUTIN G (—> ) DIVERSION O R PUM P FLOW

( .) CONNECTOR <<---) RETURN OF DIVERTED OR PUMPED FLOW

3alpi nV

V

ditch3

21 3woods

26

29

DITCH3 . V

V

3outf l

32

37

4alpi nV

V

ditch4

40 4woods

45

48

3and4.

V

V

4at2

51

56

1woods

V

V

loutf l

59

64

2alpi n

V

V

ditch2

67 2 woods

72 1and2.V

V

2at4

78 4and2.

V
RUNOF F SUMMAR Y FLOW IN CUBI C FEE T PE R SECON D

TIM E IN HOURS , AREA IN SQUAR E MILE S

OPERATIO N

HYDROGRAPH A T

ROUTED T O

HYDROGRAPH AT

2 COMBINED AT

ROUTED T O

HYDROGRAPH A T

ROUTED TO

HYDROGRAPH AT

3 COMBINED AT

ROUTED T O

HYDROGRAPH A T

ROUTED TO

HYDROGRAPH AT

ROUTED TO

HYDROGRAPH A T

3 COMBINED AT

ROUTED TO

2 COMBINED AT

ROUTED TO

HYDROGRAPH A T

2 COMBINED AT

STATIO N

3atpi n

ditch3 .

3woods

DITCH 3

3outf l

4alpi n

ditch4

4 woods

3and4

4at2

1 woods

loutf l

2alpi n

ditch2

2woods

1and2

2at4

4and2

4outf l

Iouer4

CalGu l

PEA< FLOW

12.

11.

1.

12.

11.

29.

26.

2.

39.

39.

0.

0.

23.

21.

1.

23.

23.

62.

62.

0.

62.

TIM E O F

PEAK

12.00

12.50

12.50

12.50

12.50

12.00

12.50

12.50

12.50

12.50

12.50

12.50

12.00

12.50

12.50

12.50

12.50

12.50

12.50

12.50

12.50

AVERAG E

6- HOUR

3.

3.

0.

3.

3.

6.

6.

1.

11.

11.

0.

0.

5.

5.

1.

6.

6.

17.

16.

0.

16.

FLOW FOR MAXIMUM

24-HOUR

1.

1.

0.

1.

1.

2.

2.

0.

4.

4.

0.

0.

2.

2.

0.

2.

2.

6.

6.

0.

6.

PERIO D

72-HOUR

1.

1.

0.

1.

1.

2.

2.

0.

4.

4.

0.

0.

2.

2.

0.

2.

2.

6.

6.

0.

6.

BASI N

AREA

0.03

0.03

0.03

0.06

0.06

0.08

0.08

0.07

0.21

0.21

0.01

0.01

0.06

0.06

0.05

0.12

0.12

0.32

0.32

0.01

0.33

MAXIMU M TIM E O F

STAG E MA X STAG E
July 27, 1995 FINAL * EE/CA Garibaldi Mine Site * Appendices

APPENDIX B-2

HEC-1 MODEL ALTERNATIV E D

H:\664\EECA\GAR1BALD.FNL

07/27/95 4:01pm WP51/cmc
HEC 1 S/N : 0134300665 HMVersion : 6.33 Data File : garaltd.hd

*************************************

* FLOO D HYDROGRAPH PACKAG E (HEC-1 ) *

* MAY 1991 *

* VERSION 4.0.I E * * *

* RUN DAT E 05/11/1995 TIME 74:33:34 *

***************************************

* *

* U.S . ARMY CORPS OF ENGINEER S 

HYDROLOGI C ENGINEERIN G CENTE 

6 09 SECOND STREET *

DAVIS , CALIFORNI A 95616 

(916) 756-1104 *

***************************************** ***************************************

X

X

X

X

X

X

xxxxxxx

X

X

X

X

X

X

xxxxxxx

X

X

xxxx

X

X

xxxxxxx

xxxxx

X X

X

X

X

X X

xxxxx

xxxxx

X

XX

X

X

X

X

X X X

Ful l Microcomputer Implementatio n

by Haestad Methods , Inc .

37 Brookside Road * Waterbury, Connecticut 06708 * (203 ) 755-1666

THI S PROGRAM REPLACES AL L PREVIOU S VERSION S O F HEC-1 KNOWN A S HEC 1 (JAN 73), HEC1GS , HEC1DB , AN D HEC1KU .

T H E DEFINITION S O F VARIABLE S -RTIMP - AN D -RTIOR - HAV E CHANGE D FROM THOS E USE D WIT H TH E 1973-STYL E INPU T STRUCTURE . T H E DEFINITION O F -AMSKK - ON RM-CAR D WA S CHANGE D WITH REVISION S DATE D 2 8 SE P 81 . THI S I S TH E FORTRAN7 7 VERSION

N EW OPTIONS : DAMBREAK OUTFLO W SUBMERGENC E , SINGL E EVEN T DAMAG E CALCULATION , DSS:WRIT E STAG E FREQUENCY , DSS:REA D TIM E SERIE S A T DESIRE D CALCULATION INTERVA L LOS S RATE:GREEN AN D AMP T INFILTRATION

KINEMATI C WAVE : NE W FINIT E DIFFERENC E ALGORITHM
HEC-1 INPU T PAG E 2

LIN E ID.......1.......2.......3.......4.......5.......6.......7.......8.......9......10

38 KK upper2Alpin e Overland Flow Routed to Upper Ditch 2

39 KM route alpin e flo w through woods to upper ditch #2

40 RM -1 0.119 0.339

41 KK 2woodsUpper Ditch 2 Woods Subwatershed Generation

42 KM runof f from woods that drain s to upper ditch #2

43 BA 0.0883

44 LS 0 60

45 UD 0.145

46 KK UPPER2Upper Ditch 2 Flo w

47 KM combine runof f from alpin e and woods subuatersheds

48 HC 2

49 KK 2at1Route Upper Ditch 2 Hydrograph to junctio n with Ditch 1

50 KM route flo w through upper ditch 2 to ditch 1 inflo w

51 RK 330 0.19 0.035 TRAP 2 2

52 KK 2at1Combine Ditch 1 hydrograph with Upper Ditch 2 hydrograph

53 KM comined hydrograph for ditch 1 and upper ditch 2

54 HC 2

55 KK calgulRout e combined hydrograph through lower ditch 2 to Cal Gulch

56 KM Combined hydrograph routed to Cal Gulch

57 RK 400 0.13 0.035 TRAP 2 2

58 KK 2lowerLower Ditch 1 Woods Subwatershed Generatio n

59 KM runof f from woods that drain s to lower ditch #2

60 BA 0.0125

61 LS 0 60

62 UD 0.0570

63 KK calgulRout e Lower Ditch 2 flo w to Cal Gulch

64 KM route lower ditch 2 flo w to Cal Gulch

65 RK 400 0.13 0.035 TRAP 2 2

66 KK CalGu l

67 KM combined flo w i n Californi a Gulch below Garibaldi Pil e

68 HC 2

69 ZZ
RUNOF F SUMMAR Y FLOW IN CUBI C FEE T PE R SECON D

TIM E I N HOURS , ARE A I N SQUAR E MILE S

OPERATION

HYDROGRAPH A T

ROUTED TO

HYDROGRAPH AT

2 COMBINED AT

ROUTED TO

HYDROGRAPH A T

ROUTED TO

HYDROGRAPH AT

2 COMBINED AT

ROUTED TO

2 COMBINED AT

ROUTED TO

HYDROGRAPH AT

ROUTED TO

2 COMBINED AT

STATIO N

lalpi n

ditcM

2woods

DITCH 1

1at2

2alpi n

upper2

2woods

UPPER 2

2at1

2at1

calgul

2 lower

calgul

CalGu l

PEAK

FLOW

29.

26.

2.

28.

28.

33.

29.

3.

32.

32.

60.

60.

0.

0.

60.

TIM E OF

PEAK

12.00

12.50

12.50

12.50

12.50

12.00

12.50

12.50

12.50

12.50

12.50

12.50

12.50

12.50

12.50

AVERAG E

6- HOUR

7.

7.

1.

7.

7.

7.

7.

1.

9.

9.

16.

16.

0.

0.

16.

FLOW FOR MAXIMUM

24- HOUR

2.

2.

0.

3.

3.

3.

3.

0.

3.

3.

6.

6.

0.

0.

6.

PERIOD

72- HOUR

2.

2.

0.

3.

3.

3.

3.

0.

3.

3.

6.

6.

0.

0.

6.

BASIN MAXIMUM TIM E O F

AREA STAG E MA X STAG E

0.08

0.08

0.06

0.13

0.13

0.09

0.09

0.09

0.17

0.17

0.31

0.31

0.01

0.01

0.32
July 27, 1995 FINAL * EE/CA Ganbaldi Mine Site * Appendices

APPENDIX C

HELP MODEL

H:\664\EECA\GARIBAID.FNL

07/27/95 4:01pm WP51/cmc
June 2, 1995 HELP Model * Appendix C * Page C-l

Thi s appendix discusses infiltratio n rates for the Garibaldi waste rock pile using the U.S. EPA Hydrologic Evaluation of Landfil l Performance (HELP) model. Infiltratio n was estimated for

bare tailings and was then compared to infiltratio n rates for various cover systems.

C .I Cover Scenarios

T he tailings cover scenarios analyzed are provided below:

Bare tailings Design 1 - Existing weathered cap Design 2 - Simpl e cover

Existin g weathered cap consists of approximately 12-inches off weathered waste rock. The

simple cover consists of an 18-inch thick layer of borrow soil.

C .2 HELP Modellin g

T he U.S. EPA HELP Model version 2 was used to predict infiltratio n and runof f for the waste

rock pile.

T he infiltratio n modellin g was conducted utilizin g HELP's synthetic weather generator. Grand Junction , Colorado, was seleaed from the HELP Model climatic database of cities for climatic

generation. Grand Junction was seleaed bused on its close proximity to Leadville latitude and

climatic conditions. Table C.I shows average monthly temperature data from 1895 to 1960 and

average monthly precipitation data from 1905 to 1960 for Leadville (U.S. Weather Bureau, 1960)

that was entered in the HELP Model to increase the accuracy of the calculations. In addition, Table C.2 shows the humidity data for Leadville, which was entered to increase the accuracy

of the model.

TABLE C.1 AVERAG E MONTHL Y TEMPERATUR E AN D PRECIPITATION

A vg Tem p ( F )

A vg Precip

(in )

J AN

17.9

1.32

F EB

19.3

1.51

M AR

23.2

1.71

A PR

32.2

1.83

M AY

42.0

1.44

J UN

51.4

1.13

J U L

56.9

2.73

A U G

55.6

2.11

S EP

49.6

1.35

OCT

39.4

1.11

N OV

26.4

1.07

DEC

20.3

1.17

TABLE C.2 QUARTERLY AVERAG E HUMIDIT Y IN LEADVILL E

% Humidit y

1 st Quarter

52.3

2nd Quarter

52.6

3rd Quarter

64.3

4th Quarter

47,7

The input parameters used or climatic conditions were: 1) a latitude of 39.14; 2) a leaf area

index of 1.60 for covers with vegetation (the maximum supportable without irrigation); 3) a leaf

area index of 0.00 for covers with no vegetation; 4) 20 years of weather generation; 5) an 18-inch

H:\664\EECA\GARAPP.C

06/01/95 6:29am WP51/cmc
July 27, 1995__________ ______ FINAL * EE/CA Garibaldi Mine Site * Appendices

APPENDIX C-1

HELP MODEL OUTPU T

GARIBALD I WEATHERED CA P

H:\664\EECA\GARBALD.FNL

07/27/95 4:01pm WP51/cmc
* *

** HYDROLOGI C EVALUATION OF LANDFIL L PERFORMANCE HELP MODEL VERSION 3.03 (31 DECEMBER 1994} DEVELOPED BY ENVIRONMENTAL LABORATORY

USA E WATERWAY S EXPERIMEN T STATION F OR USEPA RISK REDUCTION ENGINEERING LABORATORY

PRECIPITATIO N DAT A FILE : TEMPERATUR E DAT A FILE : SOLAR RADIATION DATA FILE : EVAPOTRANSPIRATION DATA : SOI L AN D DESIGN DATA FILE : OUTPU T DAT A FILE :C:\HELP3\LEAD.D 4

7 C:\HELP3\GJLEAD.D1 3 C:\HELP3\GJLDO.Dl l C:\HELP3\GBEXIST.D1 0 C:\HELP3\GBEXIST.OU T

TIME : 9:27 DATE : 5/31/199 5

TITLE : GARIBALD I WEATHERE D CA P

NOTE : INITIA L MOISTUR E CONTEN T OF TH E LAYERS AND SNOW WATE R WERE COMPUTE D AS NEARLY STEADY-STATE VALUES BY THE PROGRAM.

LAYER 1

TYP E 1 - VERTICA L PERCOLATION LAYER MATERIAL TEXTUR E NUMBER 10 THICKNES S

POROSIT Y FIEL D CAPACIT Y WILTIN G POIN T INITIA L SOI L WATER CONTENT

EFFECTIV E SAT . HYD . COND.

12.00 INCHE S

0.3980 VOL/VO L

0.2440 VOL/VO L

0.1360 VOL/VO L

??????????? VOL/VO L

0.119999997000E-03 CM/SE C

GENERAL DESIGN AND EVAPORATIV E ZONE DATA

NOTE : SCS RUNOFF CURVE NUMBER WAS COMPUTED FROM A USER- SPECIFIE D CURVE NUMBER OF 86.0, A SURFAC E SLOPE OF 31.% AND A SLOPE LENGTH OF 100. FEET .

S CS RUNOFF CURVE NUMBER

FRACTION OF . AREA ALLOWING RUNOF F AREA PROJECTED ON HORIZONTAL PLANE

EVAPORATIV E ZONE DEPTH INITIA L WATER IN EVAPORATIV E ZONE UPPER LIMIT OF EVAPORATIV E STORAG E LOWER LIMIT OF EVAPORATIVE STORAG E INITIA L SNOW WATER

INITIA L WATER IN LAYER MATERIALS TOTA L INITIA L WATE R

TOTA L SUBSURFAC E INFLOW

=

=

=

=

=

=

=

=

= ?•>

=•>•>

87.80

100.0

1.600

12.0

2.627

4.776

1.632

0.000

•> •> •> •} •) •>•> •> •>

PERCENT ACRES

INCHE S

INCHE S

INCHE S

INCHE S

INCHE S

INCHE S

0.00 INCHES/YEA R
PERCOLATION/LEAKAGE THROUGH LAYER 1

TOTAL S

STD . DEVIATION S

0.0000

0.4112

0.0000

0.4575

0.0000

0.2964

0.0000

0.4550

0.0167

0.0908

0.0745

0.1869

0.0972

0.0759

0.2171

0.3074

0.2416

0.0124

0.3449

0.0285

0.1831

0.0007

0.3638

0.0032

PRECIPITATIO N

RUNOF F

EVAPOTRANSPIRATION

PERCOLATION/LEAKAG E THROUGH

17.

2.

13.

1.

INCHE S

.69 (

.804 (

.437 (

.42583 (

C U . FEET

2

1.

2.

0.

.573 )

3625 )

2036 )

64216 )

102726.

16283.

78044.

8281.

.1

.31

.84

.223

PERCENT

100.

15.

75.

8.

.00

.851

.974

.06146

CHANG E IN WATER STORAG E 116.73 0.114
FINAL WATER STORAG E AT END OF YEAR 20

LAYER '(INCHES ) (VOL/VOL )

1 ??????????? ?????????

SNOW WATER 0.000
July 27, 1995 FINAL * EE/CA Garibaldi Mine Site * Appendices

APPENDIX C-2

HELP MODEL OUTPU T

GARIBALD I SIMPL E COVER

H:\664\EECA\GARIBALD.FNL

07/27/95 4:01pm WP51/cm c
* *

* *

* *

* *

* *

HYDROLOGI C EVALUATION OF LANDFIL L PERFORMANC E HELP MODEL VERSION 3.03 (31 DECEMBER 1994 ) DEVELOPED BY ENVIRONMENTAL LABORATORY

USAE WATERWAY S EXPERIMENT STATION F OR USEPA RISK REDUCTION ENGINEERING LABORATORY

* *

**

PRECIPITATION DAT A FILE : TEMPERATUR E DATA FILE : SOLAR RADIATION DATA FILE : EVAPOTRANSPIRATION DATA : SOI L AN D DESIGN DATA FILE : OUTPUT DATA FILE :

C:\HELP3\LEAD.D 4

7 C: \HELP3\GJLEAD.D1 3 C:\HELP3\GJLEAD.D1 1 C:\HELP3\GBCOVER.D1 0 C: \HELP 3 \GBCOVER. OUT

TIME : 9: 9 DATE : 5/31/199 5

TITLE : GARIBALD I SIMPL E COVER

NOTE : INITIA L MOISTUR E CONTENT OF TH E LAYERS AND SNOW WATER WERE COMPUTED AS NEARLY STEADY-STATE VALUES BY THE PROGRAM.

LAYER

TYPE 1 - VERTICA L PERCOLATION LAYER MATERIAL TEXTUR E NUMBER 6 THICKNES S = 18.00 INCHE S

POROSIT Y = 0.4530 VOL/VO L FIEL D CAPACIT Y = 0.1900 VOL/VO L WILTING POINT = 0.0850 VOL/VO L INITIA L SOI L WATE R CONTEN T =???????????? VOL/VO L

EFFECTIV E SAT . HYD . COND. = 0.720000011000E-03 CM/SE C NOTE : SATURATED HYDRAULI C CONDUCTIVIT Y I S MULTIPLIE D B Y 2, F OR ROOT CHANNELS IN TOP HALF OF EVAPORATIV E ZONE .

49

GENERAL DESIGN AND EVAPORATIV E ZONE DATA

NOTE : SCS RUNOFF CURVE NUMBER WAS COMPUTED FROM A USER- SPECIFIE D CURVE NUMBER OF 80.0, A SURFACE SLOPE OF 29.% AND A SLOP E LENGTH OF 120. FEET .

S CS RUNOFF CURVE NUMBER

FRACTION OF AREA ALLOWIN G RUNOFF AREA PROJECTED ON HORIZONTAL PLANE

EVAPORATIV E ZONE DEPTH INITIA L WATER IN EVAPORATIV E ZONE UPPER LIMIT OF EVAPORATIVE STORAG E LOWER LIMIT OF EVAPORATIVE STORAGE INITIA L SNOW WATER

INITIA L WATE R IN LAYER MATERIALS TOTA L INITIA L WATER

TOTAL SUBSURFAC E INFLOW

82.50

100.0

1.600

18.0

2.849

8.154

1.530

0.000

=???????????

=???????????

0.00

PERCENT ACRES

INCHE S

INCHE S

INCHE S

INCHE S

INCHE S

INCHE S

INCHE S

INCHES/YEA R
STD . DEVIATION S

PERCOLAT I ON / LEAKAG E

TOTAL S

STD . DEVIATION S

0.

1.

THROUGH

0.

0.

0.

0.

251

080

LAYER

0000

2533

0000

5243

0.150

0.982

1

0.0000

0.1945

0.0000

0.3065

0

0

0

0

0

0

.389

.920

.0000

.0415

.0000

.1075

0.543

0.522

0.0006

0.0422

0.0016

0.1561

0..892

0.278

0.1010

0.0174

0.2644

0.0775

0.914

0.310

0.1185

0.0003

0.3206

0.0014

AVERAGE ANNUAL TOTALS &

PRECIPITATIO N

RUNOF F

EVAPOTRANSPIRATIO N

PERCOLATION/LEAKAG E THROUGH

(STD .

17.

2.

14.

0.

DEVIATIONS )

INCHE S

69 (

291 (

613 (

76927 (

F OR YEAR S 1 THROUGH

C U . FEE T

2

1.

2.

0.

.573 )

2137 )

3894 )

68466 )

102726

13306

84871

4467

.1

.50

.07

.936

20

PERCENT

100.00

12.953

82.619

4.34937

CHANG E IN WATER STORAG E 80.61 0.078
FINAL WATE R STORAG E AT END OF YEAR 20

LAYER (INCHES ) (VOL/VOL )

1 ??????????? ?????????

SNOW WATER 0.000
July 27, 1995 FINAL * EE/CA Garibaldi Mine Site * Appendices

APPENDIX D

SOI L LOSS CALCULATION S

H:\664\EECA\GARBALD.FNL

07/27/95 4:01pm WP51/cmc
ANNUA L SOI L LOSS CALCULATION S METHODOLOGIES AN D ASSUMPTION S

1.0 SEDCAD + SEDIMENTATION COMPUTER MODEL

Sediment yield was determined for a single storm event (10-year 24-hour) and converted to an

annual yield.

The calculations to determine the storm sediment yield were performed by the use of the SEDCAD + Computer Model developed by Civil Software Design.

T he SEDCAD-t- model determines soil loss using the Revised Universal Soi l Loss Equation

(RUSLE) with the followin g input parameters:

Y = 95*(V*Qp)°-56*K*LS*CP

Where: Y = Sediment yield (tons) V = Runoff volume (acre-feet) Q

p

 = Peak discharge (cfs) K = Soi l credibility factor LS = Representative length-slope factor CP = Control practice factor

T he length-slope factor for the RUSLE subroutine is as follows:

LS = —^— * (slope factor) 72.6

Where: X = Representative slope length (ft)

m = 0.6 for slope > 10%

m = 0.5 for 4% < slope < 10%

m = 0.4 for slope = 4%

m = 0.3 for slope < 4%

The slope factor is a piecewise linear relationship with the slope breakpoint at 8% as shown on Figure 5.5, Slope Factor for the RUSLE, contained in the SEDCAD + Users Manual..

Input s for the sedimentology portion of the SEDCAD+ routine are:

Runof f volume Peak discharge Soi l erodibility factor Representative slope length Average slope Control practice factor Sediment specific weight

H:\6M\EECA\GARIBALD.APD

06/01/95 7:00am WP51/cmc
1.5 Control Practice Factor, CP

T he control practice factor is defined as the ratio of sediment loss from an area with a given

cover and conservation practice to that of a field in continuous fallow . The followin g values

were utilized:

Cover Condition

Existin g Cemented Simpl e Cover No appreciable canopy, 20% grass

CP

0.3

0.20

1.6 Annual sediment yield, V,innual

Sedimen t yields calculated by SEDCAD + for single storm events can be converted to annual

yields by the followin g equation:

annual

D

_ annual Rstorm

Where: V,

-D

annual

•annual

F or a SCS Typ e H Storm:

Annual sediment yield (tons/yr) Single storm rainfal l factor Single storm rainfal l factor Settlemen t yield for 10-yr, 24-hr storm event (tons)

Rannual = 27*(P 2

,

6 )

2.2

Where: 2-yr, 6-hr precipitatio n in inches = 0.8 inches

Rstorm

19 .25

£j0.4672

,2.2

Where: 10,24 D

10-yr, 24-hr precipitation in inches = 1.6 inches Storm Duration = 24 hours

2.0 RESULT S

Soi l loss analyses were conducted for alternatives A through C. The followin g are the results:

Alternative A & B Alternative C 6.1 tons/acre/year

1.0 tons/acre/year

H:\664\EECA\GARBALD.APD

06/01/95 7:00am WP51/cmc
July 27, 1995 FINAL * EE/CA Garibaldi Mine Site '• Appendices

APPENDIX D-1

SEDCAD + PRINTOUT S

H:\664\EECA\GARBALD.FNL

07/27/95 4:01pm WP51/cmc
CIVI L SOFTWAR E DESIG N

SEDCAD + Version 3

GARABALDI : SOI L LOS S FO R EXISTIN G CONDITION S

by

Name: TEL

Company Name: ACZ , INC . Fil e Name: D:\TOM\RESURECT\GBASI S

Date: 03-30-1995
CIVI L SOFTWAR E DESIG N

SEDCAD + Versio n 3

GARABALDI : REGRADED AN D SIMPL E SURFAC E

by

Name: TEL

Company Name: ACZ , INC . Fil e Name: D:\TCM\RESURECT\GBREG R

Date: 03-16-1995
July 27, 1995 _____ FINAL * EE/CA Garibaldi Mine Site * Appendices

APPENDIX D-2

SOI L ERODIBILIT Y NOMOGRAPH

H:\664\EECA\GARBALD.FNL

07/27/95 4:01pm WP51/cmc
vo

u4V) Xlu

VJ

\

ONVS 3NU XH3A «• US JJOOWJd

•H C

~4 O u ui U

CM (0 — i-( US •H O W O J O 60-H M C O tu <H CO IU 9 OaCOVi M

7.1-290
July 27, 1995 ____________ FINAL * EE/CA Garibaldi Mine Site * Appendices

APPENDIX E

STABILIT Y ANALYSI S

H:\6fr4\EECA\GARBALD.FNL

07/27/95 4:01pm WP51/cmc
STABILIT Y ANALYSI S GARIBALD I MIN E SIT E ALTERNATIV E A THROUGH C

In Alternatives A and B the waste rock pile will remain in this current configuration. The

waste rock pile is approximatel y 30 feet high with 1.4H:1V slopes. The waste rock pile has

been in existences for more than 50 years with no indications of instability or surface failure. Given this observation, it can be concluded that the waste rock pile in its current configuration

has a Factor of Safet y of at least 1.0 or greater. However, given the current information on the

waste rock material it is difficul t to determine the actual Factor of Safet y for the current

configuration. If there was a failure due to earthquakes, and/or heavy precipitatio n events, there

would be most likel y a minor shallow surface failure. Given the configuration of the waste rock

pile, this type of failure would have little or no effec t on the proposed access road and/or the

proposed drainage diversions.

In Alternative C, the slopes will be regraded to 3H:1V. Waste rock material properties for the

stabilit y analysis of the regraded slopes were determined through back analysis of the existing

conditions. The back analysis was conducted using XSTABL computer software. The Bishop met

1

- >d was selected within XSTABL for computing the Factor of Safety . The back analysis

was conducted on the highest and steepest cross-section as shown on the XSTABL computer

printouts, assuming drained conditions, a cohesion equal to 0, and a Factor of Safet y of 1.0.

Using this approach, a maximum internal friction angle of 36 was determined.

T he material properties determined in the back analysis were then used to determine the Factor

of Safet y for the regraded slopes. With an average regraded slope of 3H:1V and drained

conditions, the Factor of Safet y for Alternative C was greater than 2.0. In addition , the Factor

of Safet y under pseudostatic conditions was determined. Pseudostatic conditions were simulated

using the seismic acceleration coefficien t (k) of 0.04g for 50 year return, this value was

established by review of published data for Algermissen (1991) and was checked against data

published by Dames and Moore in Stabilit y and Reclamation Evaluation of Abandoned Tailings Pond (1986). The Factor of Safety for the regraded slopes under psuedostatic conditions is 2.0.

A ll inputs, cross-sections, failure surfaces, and results are shown on the XSTABL computer

printout s contained in Appendix E-l.

H:\664VEECA\GARAPP-E.TXT

06/01/95 7:3 lam WPS 1/cmc E-l
July 27, 1995 FINAL * EE/CA Garibaldi Mine Site * Appendices

APPENDIX E-1

XSTAB L COMPUTE R PRINTOUT S

H:\664\EECA\GARJBALD.FNL

07/27/95 4:01pm WP51/cmc
EXIST 4-12-95 12:16

225 _

195 _

0) 165

<D

C /3

i —i X

< 135

105 _

75

GARIBALD I EXISTIN G CONDITION S

10 most critical surfaces , MINIMUM BISHOP FOS - 1.035

30

T

60 90 120 150 X-AXI S (feet )

180 210 240
ISOTROPI C Soi l Parameters

2 type(s ) of soil

Soi l Unit Weight Cohesion Frictio n Pore Pressure Water Unit Moist Sat . Intercept Angle Parameter Constant Surfac e N o . (pcf ) (pcf ) (psf ) (deg ) R u (psf ) No .

1 126.0 132.0 .0 36.00 .000 .0 1

2 150.0 150.0 .0 50.00 .000 .0 1

1 Water surface(s ) have been specified

Unit weight of water = 62.40 (pcf)

Water Surfac e No. 1 specified by 2 coordinate point s

**********************************

PHREATI C SURFACE , **********************************

Point x-water y-water N o . (ft ) (ft )

1 80.00 135.00

2 142.00 135.00

A critical failure surface searching method, using a random

technique for generating CIRCULAR surfaces has been specified.

100 trial surfaces will be generated and analyzed.

10 Surfaces initiate from each of 10 points equally spaced

along the ground surface between x = 90.0 ft

and x = 125.0 ft

Each surface terminates between x = 126.0 ft

and x = 212.0 ft

Unless further limitations were imposed, the minimum elevation

at which a surface extends is y = 120.0 ft

5 .0 ft line segments defin e each trial failure surface.

ANGULAR RESTRICTION S :
m)l 4-12-95 12:24 C

225 _

195 _

0) 165 _

0)

C /3 i —i X

I

135 _

105 _

75

0

GARIBALD I REGRADED (.04G )

10 most critical surfaces , MINIMUM BISHOP FOS = 1.988

i

30

i

60 90 120 150

X-AXI S (feet )

180 210 240
Soi l Unit Weight Cohesion Frictio n Pore Pressure Water Unit Mois t Sat . Intercept Angle Parameter Constant Surfac e N o . (pcf ) (pcf ) (psf ) (deg ) R u (psf ) No .

1 126.0 132.0 .0 36.00 .000 .0 1

2 150.0 150.0 .0 50.00 .000 .0 1

1 Water surface(s ) have been specified

Unit weight of water = 62.40 (pcf )

Water Surfac e No. 1 specified by 2 coordinate point s

**********************************

PHREATI C SURFACE , **********************************

Point N o .

1

2

x-water

(ft )

80.00

142.00

y-water

(ft )

135.00

135.00

A horizontal earthquake loading coefficien t

of .040 has been assigned

A vertical earthquake loading coefficien t

of .000 has been assigned

A critical failure surface searching method, using a random

technique for generating CIRCULAR surfaces has been specified.

100 trial surfaces will be generated and analyzed.

10 Surface s initiate from each of 10 points equally spaced

along the ground surface between x = 70.0 ft

and x = 125.0 ft

Each surface terminates between x = 126.0 ft

and x = 212.0 ft

Unles s further limitation s were imposed, the minimum elevation

at which a surface extends is y = 120.0 ft

5 .0 ft line segments defin e each trial failure surface.
( !T01 4-12-95 12:26

225 _

195 _

0) 165 _

0)

Ci —O( X

<CI

135 _

105 _

75

0

GARIBALD I REGRADED

10 most critical surfaces , MINIMUM BISHOP FOS = 2.261

30

i

60 90 120 150

X-AXI S (feet )

180 210 240
. q.TuiTT : = ) adois B aifiu - 9 (o* p saajBa

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f q.safg s ^uauiba 0 3: a qoe : aanifeg

S o * s sq.uaui6a p auTja

s aoejan a spuaq.x T S A = T 0*02 5 ^•

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1 0*92

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B PU x =

> punoa£ s aoejan q uaaMq.a x =i O'O

1 0 s saoBjan t aq.BTq.TU j uioa a qoe o j i o d sq.uTo

 TTT q a 6 paq.Baaua B P U

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i oo . TBTJtq s saoBjan

j ao 6 6uTq.BJ:aua D HVinDHI s saoBjan ^ s q uaa s •pajgiToad

 v o iBOTq.Ta j aantTB s aoBjan s fiuTqoaBa i 'ponqau n £>uTs B

T 00*9C T 00-9C T OO'Sfr8 00*0

Z

I

N • O

d q.uTO

* *********************************

* *********************************

s aoBjan N -O i s paTjToad q A z o 9q.BUTpaoo d sq.uTo

9 Ofr'2 ) (jod

q uaa s paTjToad

n q.Tu i q.qTa/ oj

 T M Jaq.B s (s)aoBjan

I

i

N • O

0 *

o

0 00

o oo

) (jsd

o qsu

d aanssaa

9 00*0

e oo*9

) (6ep

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Z

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u

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q.J

u S IT° n
July 27, 1995 FINAL * EE/CA Garibaldi Mine Site * Appendices

APPENDIX F

ARARs

H:\664\EECA\GARBALD.FNL

07/27/95 4:01pm WP51/cmc
APPENDIX F ARARs

Thi s appendix identifies all requirements that EPA has determined are Applicable or Relevant

a nd Appropriat e Requirements ("ARARs") for the Garibaldi Mine Site removal action.

As a matter of policy , EPA requires attainment of ARARs in removal actions to the greatest

extent practicable given the exigencies at a given site. See CERCLA Compliance With Other Laws Manual at xii, EPA-540-6-89-006 (Interim Final , August 1988). EPA generally determines

that compliance with ARARs is practicable for "non-time-critical" removal actions, such as this

one. Resurrection takes no position with respect to the propriety of this polic y and it reserves

all rights that it may have with respect to complying with it.

In accordance with EPA's directive, all requirements that EPA has determined are ARARs for

this removal action will be met unless EPA determines that compliance is not practicable or

compliance is waived in accordance with Section 300.430(f)(ii)(C) of the National Contingency Plan. Attainment of water-quality based, chemical-specific ARARs is not required until

implementation of the remedial action for Site-wide Surface and Ground Waters (see Resurrection WAMP § 4.6.5).

T he potential ARARs identified below were selected based on standards, guidelines and criteria

found in relevant literature; discussions with appropriate regulatory agency personnel; and prior

project experience. The principal references used were:

• Preliminary Applicabl e or Relevant and Appropriate Requirements Analysis, Appendix A, Final Screening Feasibilit y Study for Remedial Alternatives at the California Gulch NPL Site , Leadville, Colorado (September 1993) (the "Final SFS") ;

• Guidance on Conducting Non-Time-Critical Removal Actions Under CERCLA, EPA/540/R-93/057 (August 1993);

• Guidance on the Consideration of ARARs During Removal Actions, EPA/540/P91/011 (September 1991); and

• CERCLA Compliance With Other Laws Manual, EPA/540/G-89/006, (Interim Final) (August 1988).

A detailed analysis of the potential ARAR selection process and a description of the terms used

below can be found in Sections Al - A5 of the Final SFS.

F .1 CHEMICAL-SPECIFI C ARAR S

Chemical-specific requirements are based on health or risk-based concentration limit s or

discharge limitations in environmental media (i.e., water, air) for specific hazardous chemicals. These requirements may be used to set cleanup levels for the chemicals of concern (in this case,

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

taking into account water quality standards) where a discharge occurs as part of the remedial

activity.

H:\664\EECA\GARIBALD\GARAPPF.TXT

07/27/95 4:04pm WPS 1/cmc F-1
F.1.1 Waste Classificatio n

The waste under consideration is waste rock. The source of contamination is the Garibaldi

waste rock pile. Based on 40 CFR 261.4(b)(7), these wastes are excluded from Resource

Conservation and Recovery Act (RCRA) Subtitl e C. For this reason, RCRA Subtitl e C is not

applicable as a matter of law to these wastes for this removal action.

Based on 6 CCR 1007-3, Section 261.4(b)(7), these wastes are also excluded from the Colorado Hazardous Waste Act. For this reason, the Colorado Hazardous Waste Act is not a potential ARAR for this removal action.

F.1.2 To Be Considered Items ("TBC" ) for Soi l

T he EPA has issued an Offic e of Solid Waste and Emergency Response (OSWER) directive

entitled "Interim Guidance on Establishing Soi l Lead Cleanup Levels at Superfun d Sites"

(OSWER Directive #9355.4-02, September 1989). The directive sets forth interim soil cleanup

levels when the land use is residential and is intended solely as guidance. However, Upper California Gulch is not designated for residential use nor does EPA foresee residential use as a

reasonable future land use. For this reason, OSWER Directive #9355.4-02 is not a potential ARAR for this removal action.

F.1.3 Summary

As discussed on page F-l, there are no chemical-specific requirements that are applicable or

relevant and appropriate requirements for this removal action.

F .2 LOCATION-SPECIFI C ARAR S

Location-specific ARARs are restrictions placed on the types of activities that may occur in

particular locations. The location of a site may be an important characteristic in determining

i ts impact on public health and the environment; thus state standards often establish locationspecific ARARs. These ARARs may restrict or preclude certain remedial actions or may appl y

only to certain portions of a site. Examples of location-specific ARARs include federal and state

requirements for preservation of historic landmarks, endangered species and wetlands protection,

and floodplai n restrictions on management of hazardous waste.

F.2.1 Threatened/Endangered Species

If Threatened/Endangered species are found to inhabit areas that will be impacted by activities,

t he Federal Endangered Species Act and the State Nongame, Endangered, or Threatened Species Act will be applicable and coordination with federal and state agencies will be needed to

implement mitigation measures or alternative removal activities.

A Terrestrial Ecosystem Evaluation (TEE) (WCC, 1993) was conducted in the California Gulch

site as part of the Phase n Remedial Investigations. The TEE stated that no evidence of the

potential presence of threatened, endangered or sensitive species was found within the study area

(WWC, 1993). For this reason, the Federal Endangered Species Act and the State Nongame

Endangered or Threatened Species Act are not potential ARARs for this removal action.

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F.2.2 Species of Special Concern and Undetermined Status

Under Colorado Law (or policy), the Colorado Department of Natural Resources (CDNR) has

established two designations to protect wildlif e species. These two designations are "species of

special concern" and "species of undetermined status". Species of special concern are defined as

native species or subspecies which have been threatened or endangered or could become

threatened or endangered due to low populatio n levels. Species of undetermined status are

species about which too little is known to accurately determine their status in the state. Colorado' s Division of Wildlif e maintains a list of species which have been determined to fit

these categories. If species of special concern or of undetermined status are foun d at the site and

removal activities could potentiall y impact those species (or their habitats), the Division of Wildlife's Directive E-l, 1985 (modified) , should be taken into consideration and coordination

with the Division implemented. These internal designations would be potential To Be Considered (TBCs) for this removal action only if species in either category are found in Upper California Gulch.

F.2.3 Colorado Natural Areas Program

T he Colorado Natural Areas Program maintains a list of Plant Species of Special Concern to the State of Colorado. It is not authorized by statute and is considered a planning and management

tool. If removal activities impact plan t species maintained on the list , the program is a To Be Considered (TBC) ARAR and coordination with the Colorado Division of Parks and Outdoor Recreation may be required.

F.2.4 Cultural Resources

Section 106 of the National Historic Preservation Act (NHPA) is a potential ARAR for this

removal action because the removal action is an undertaking under the NHPA. The State Historic Preservation Offic e (SHPO), however, has determined that the Garibaldi propert y "is

not individually eligible, is not within the existing Leadville Historic District and would not

contribute to the district expansion". The SHPO letter is included in Appendix A. Section

110(f) of the NHPA, which establishes procedures to minimize harm to National Historic Landmarks, is not applicable as Upper California Gulch does not lie within the Leadville National Historic Landmark District.

Executive Order 11593 on the Protection and Enhancement of the Cultural Environment is a

potential ARAR and requires consultation with the Council on the preservation and

enhancement of historic resources if removal activities should threaten them. If historical

and/or archeological data are impacted by removal activities, the Historical and Archeological Preservation Act would also be a potential ARAR.

T he Archeological Resources Protection Act of 1979 provides for the protection of cultural

resources on public or Indian lands and may be a potential ARAR with respect to removal

actions impacting such properties. The Garibaldi Mine Site removal action will impact only

private lands, not public or Indian lands.

T he State Historical , Prehistorical, and Archeological Resources Act addresses the loaning of

archeological resources on state-owned land to scientific or educational institutions. Should

removal activities endanger an archeological site that may necessitate removal of the resource,

the procedures outlined by the Act would be a potential ARAR. In addition, if removal

activities uncover any human remains that are of archeological interest, the procedures for

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excavation of remains under the act would also be "applicable or relevant, and appropriate". Finally , the State's Register of Historic Places is a potential ARAR if removal activities may

impact an area listed on the Register.

F.2.5 Wetlands and Floodplai n Management

Executive Order 11990 requires the avoidance of long and short term impacts associated with

the destruction or modification of wetlands. A wetland evaluation of the California Gulch site

conducted by Woodward-Clyde in 1992 did not identify wetlands at the Garibaldi Mine Site. However, a comprehensive wetland survey will be conducted prior to the implementation of

the recommended removal action. If any wetlands identified in this survey are impacted by the

removal action, mitigation will be addressed during the feasibilit y study for OU-4. Mitigation

will consist of wetland restoration, creation or enhancement in appropriate areas of OU-4, 8,

or 10.

Executive Order 11988 on Protection of Floodplain s is a potential ARAR. Removal must be

conducted to avoid long- and short-term adverse impacts associated with the occupation or

modification of floodplains .

F.2.6 Clean Water Act (Section 404)

Upper California Gulch is one of the major gulches on the site and contains an intermittent

stream that federal agencies, including the EPA, have determined are "waters of the United States" [33 CFR 328.3(a)]. EPA has determined that any removal r, ,</ity discharging fill

materials into, or changing the bottom elevation of, these drainages (suu; as stream diversion

ditches or construction of road crossings which impact the drainages) requires compliance with

the dredge and fill substantive requirements of Section 404 of the Clean Water Act. Pursuant

to Section 121(e) of CERCLA, EPA is not required to appl y for and obtain a Nationwide

permit. Resurrection is exempt from the permittin g process but is required to demonstrate

substantive compliance with the requirements of Section 404.

T he recommended removal action for this EE/CA will avoid dredge and fill activities in Upper California Gulch. A final determination, however, must be made by EPA.

F.2.7 Fish and Wildlife Coordination Act

Activities such as stream flow modification and construction of reservoirs or surge ponds, could

impact fish and wildlife resources in and along these drainages. The Fish and Wildlif e Coordination Act is a potential ARAR since removal activities may affect or modify Upper California Gulch. EPA may need to coordinate with both U.S. Fish and Wildlif e Service and

the Colorado Department of Natural Resources to discuss mitigation measures to prevent loss

or damage to these resources, if necessary.

The implementation of the preferred alternatives of the EE/CA will cause an improvement in

terrestrial habitat in the gulch and a reduction in the amount of water-borne contamination

leaving the gulch. Aquatic life does not exist in Upper California Gulch due to the intermittent

flow s and poor water quality. There will be no loss or damage to fish or wildlife resources in

the remediated area, therefore it is anticipated that the U.S. Fish and Wildlife Service and the Colorado Department of Natural Resources will not object to the preferred alternative

recommended in the EE/CA.

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F.2.8 Summary

Potential location-specific ARARs for removal action in Upper California Gulch are presented

in Table F.I. The removal action alternatives described in this EE/CA have been prepared in

accordance with and/or evaluated for compliance with the followin g location-specific ARARs:

• Cultural resource requirements including Section 106 of the NHPA

• Clean Water Act (Section 404)

• Fish and Wildlif e Coordination Act

F .3 ACTION-SPECIFI C ARAR S

Action-specific ARARs are activity-based requirements triggered by the particular removal

activities selected. Regulations regarding worker health and safety (i.e., GSHA requirements)

are not technically ARARs as they are not environmental or public health requirements.

F.3.1 Clean Air Act

T he Clean Air Act establishes emission standards for certain categories of industrial stationary

sources. It is only applicable if a removal action creates air emissions regulated by those

standards. Removal action activity will involve earth moving and associated dust generation. For this reason the Clean Air Act is a potential ARAR for this removal action. However, these

activities are regulated under the Colorado Air Quality Control Act and will be addressed under

its regulations as described below.

F.3.2 Colorado Air Quality Control Act

T he Colorado Air Quality Control Act establishes emissions standards for airborne particulates

and lead and is applicable if a removal action creates emissions of regulated materials. Removal

action activity will involve earth moving and associated dust generation. For this reason the Colorado Air Quality Control Act is a potential ARAR for this removal action.

It is anticipated that the removal action will be exempt from requirements to file an Air Pollutio n Emission Notice since disturbed areas will not exceed 25 acres and the duration of the

disturbance will not exceed six months. However, as stated in the EE/CA, dust abatement will

be practiced during construction. An air pollutio n control plan will be prepared and submitted

in the Remedial Design report that addresses dust abatement during all aspects of dirt work

required for the implementation of the removal action. Dust controls considered in the air

pollutio n control pla n include watering, chemical stabilizers, compaction, enclosures and

revegetation.

T he regulation of the Colorado Air Quality Control Commission require the use of all available

and practical methods which are technologically feasible and economically reasonable in order

to minimize emissions. The applicable emission limitation guideline is 20% opacity and no offproperty transport.

F.3.3 Solid Waste Disposal Act as amended by the Resource Conservation and Recovery Act

The Resource Conservation and Recovery Act (RCRA) establishes criteria for use in determining

which solid waste disposal facilities and practices pose a reasonable probabilit y of adverse effect s

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on health. RCRA is applicable to land disposal of solid waste. Since any consolidation or

disposal of solid wastes will occur entirely on-site, RCRA regulations do not appl y to this

removal action.

F.3.4 Hazardous Material s Transportatio n Act

T he Hazardous Materials Transportatio n Act regulates the off-site transportation of hazardous

materials and affect s packaging, placarding, use of proper containers, and reportin g of discharges. T he removal action in this EE/CA will not entail off-site transportation of hazardous materials

a nd therefore the Hazardous Material s Transportatio n Act is not a potential ARAR for this

removal action.

F.3.5 Occupational Health and Safet y Act and the Federal Mine Safet y and Health Act

T he Occupational Health and Safet y Act regulates worker health and safety in the workplace

and the Mine Safet y and Health Act establishes requirements to safeguard worker safet y in and

around mines. While each act will be adhered to where applicable, neither is a potential ARAR

because neither is an environmental regulation.

F.3.6 National Pollutan t Discharge Elimination System

T he National Pollutan t Discharge Elimination System (NPDES) requires permits for discharge

of pollutant s from any point source into waters of the U.S., including discharges of storm water. T he State of Colorado has an approved program for managing the NPDES permits within the

state. General permits may be obtained under a category of discharges under the Clean Water A ct for storm water point sources. The NPDES is a potential ARAR for this removal action.

A Construction Storm Water Management Plan (CSWMP) will be prepared and submitted with

t he Remedial Design report. The objective of the CSWMP will be to identif y Best Management Practices (BMPs) that will be used to reduce the pollutant s in storm water discharges associated

with construction activities. The CSWMP will be prepared according to guidelines provided by

t he State of Colorado in their General Permit Applicatio n for Discharges Associated with

Construction Activities. The CSWMP will include a site description, site map, and a description

of BMPs utilized including structural practices (straw bales, silt fences, dikes, swales), nonstructural practices (seeding, mulching, geotextiles, preservation of existing vegetation), and

material handlin g and spil l prevention procedures.

F.3.7 State Solid Waste Disposal Sites and Facilitie s Act

T he State Solid Waste Disposal Sites and Facilities Act establishes policy for licensing,

constructing, and operating solid waste disposal facilities . Permits are'not required for on-site

activities at a site listed on the NPL. Removal actions will not involve establishment of a solid

waste disposal facility. For this reason the State Solid Waste Disposal Sites and Facility Act is

not a potential action-specific ARAR for this removal action.

F.3.8 Colorado Mined Land Reclamation Act

T he Colorado Mined Land Reclamation Act regulates all aspects of land use for mining,

including the location of mining operations and related reclamation activities and other

environmental and socioeconomic impacts. A permit is not required for activities on CERCLA

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sites. EPA has determined that the followin g Colorado Mined Land Reclamaiton Board Rules

a re potential ARARs for this removal action.

• Rule 3: Reclamation Performance Standards , Inspection , Monitorin g and

Enforcement;

• Rule 7: Designated Mining Operations;

• Rule 8: Emergency Response Plan for Designated Mining Operations - Emergency Notificatio n by Operators, and Emergency Response Authority of the Office.

T he alternatives in this EE/CA will be prepared in accordance with and evaluated for

compliance with the Colorado Mined Land Reclamation Board Rules 3, 7, and 8. The

requirements of Rule 3 will be incorporated in the Remedial Design report, excepting references

to water quality standards and numeric protection levels. One of the major requirements of rule

7 is an Environmental Protection Plan. The Remedial Design report will contain an outline of

the requirements of the Environmental Protection Plan and a description of how the applicable

requirements will be met. Rule 8 requires an Emergency Response Plan. A Contingency Plan

containing an Emergency Response Plan will be prepared and contained in the Remedial Design

report.

F.3.9 Colorado Noise Abatement Act

T he Colorado Noise Abatement Act establishes maximum permissible noise levels for particular

time periods and land use zones. Removal action activities under this EE/CA will involve

, construction equipment and therefore, the Noise Abatement Act is a potential ARAR. A

summary of the regulations is provided below.

Construction project s are subject to the maximum permissible noise levels specified for industrial

zones. These are: 80 db(A) from 7:00 a.m. to next 7:00 p.m.; 75db(A) from 7:00 p.m. to next

7:00 a.m. Also, in the hours between 7:00 a.m. and the next 7:00 p.m., the noise levels may be

increased by ten db(A) for a period not to exceed fiftee n minutes in any one-hour period. Sound levels of noise shall be measured at a distance of twenty-five feet or more from the

propert y line.

Since the Garibaldi Mine site is several hundred feet from the nearest residence, it is not

anticipated that excessive noise will be a problem during the construction of this alternative. However, if excessive noise becomes a problem steps considered to remediate the problem

include: 1) operatin g during limited hours, 2) ensuring proper noise suppression equipment is

used on equipment, and 3) installin g noise screening or sound-proofing.

F.3.10 Regulations on the Collection of Aquatic Life

T he Regulations on the Collection of Aquatic Life are requirements governing the collection of

wildlife for scientific purposes and are applicable if removal action activities trigger the need for

biological monitoring. Removal actions will not trigger biological monitoring and these Regulations on the Collection of Aquatic Life are not potential ARARs.

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F.3.11 Summary

Potential action-specific ARARs for removal action in this EE/CA are discussed above and

presented in Table F.2. The removal action alternatives described in this EE/CA have been

prepared in accordance with and/or evaluated for compliance with the followin g action-specific ARARs:

Clean Air Act National Pollutant Discharge -Elimination System Colorado Air Quality Control Act Colorado Noise Abatement Act Colorado Mined Land Reclamation Act

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TABL E F.1 POTENTIA L FEDERA L AN D STAT E LOCATION-SPECIFI C ARARs

Standard, Requirement Criteria, or Limitation Citation Description

FEDERAL

Endangered Specie s Act

Fish an d Wildlife Coordinatio n Ac t

Wildernes s Act

Executive Order No. 1 1 988 Floodplai n Management

Section 404, Clean Water Act

T he Archaeological and Historic Preservation Act of 1 974

National Historic Preservation Act (NHPA )

E.O. 1 1 593 Protection and Enhancement of the Cultural Environment

T he Archeological Resources Protection Act of 1979

Resource Conservation and Recovery Act (RCRA), Subtitl e D

16 USC § 1531 et seq.

50 CFR § § 200 and 402

16 USC § 661 et seq.

40 CFR § 6.302

1 6 USC 1311,16 USC 668; 50 C FR 53, 50 CFR 27

40 CFR § 6.302 (b) Appendi x A

33 USC 1251 et seq.

40 CFR §§ 230, 231

33 CFR part s 320-330

16 USC 469; 40 CFR 6. 301 (c)

1 6 USC § 470 et seq

40 CFR § 6.301 (b)

36 CFR § Part 63, Part 65, Part

800

16 USC 470

16USC470aa-47011

40 CFR 258. 10-15

Provide protectio n for threatened and endangered species and their habitat .

These standards require protectio n of fish and wildlife in water resource

developmen t programs , or actions which impoun d divert or control or modif y any

body of water.

Limit s activities withi n areas designed as wildernes s areas or National Wildlife Refuge Systems .

Pertains to floodplai n management and construction and impoundment s in such

areas.

These standards prohibi t discharge of dredged or fil l material into waters of the United State s without permit .

Establishes procedures to provide for preservation of historical and archeological

data which might be destroyed through alteratio n of terrain as a result of a federal

construction project or a federall y licensed activit y program.

Expands historic preservation programs; applie s to resources eligibl e for listin g on

t he Natural Register for Historic Places.

Federal agencies directed to institute procedures to ensure programs contribute to

t he preservation and enhancement of non-federall y owned historic resources. Consultatio n with the Advisor y Counci l on Histori c Preservation required.

Requires a permit for any excavation or removal of archeological resources from

public lands or Indian lands . Facilitie s where treatment, storage, or disposal of solid waste wil l be conducted

must meet certain locatio n standards . These include locatio n restriction s on

proximit y to airports , floodplains , wetlands , faul t areas, seismic impact zones, an d

unstable areas.

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c

TABL E F. I POTENTIA L FEDERA L AN D STAT E LOCATION-SPECIFI C ARAR s

Standard, Requirement Criteria, or Limitation Citation Description

STATE OF COLORADO

Nongame, Endangered or Threatened Specie s Act

Colorado Register of Historic Places

Colorado Historical , Prehistorical ,

a nd Archaeological Resources Act

Colorado Specie s of Special Concern and Specie s of Undetermined Status

Colorado Natural Areas

State Solid Waste Disposal Site s

a n d Facilitie s Act , Colorado Revised Statutes , Title 30, Article

2 0, Section s 101-118

C RS §§ 33-2-101 to 108

C RS §§ 24-80.1-101 to 108

C RS §§ 24-80-401 to 410

1301 to 1305

Colorado Division of Wildlife Administrative Directive E-1,

1985, modified

Colorado Revised Statutes , Title

33, Article 33, Sec. 104

6 CCR 1007-2

6CC R 1007-2, Part i

These standards provide for the regulatio n of nongame wildlife an d threatened an d

endangered species. Authorize s State Historical Societ y to nominate propertie s for inclusio n on Stat e Register.

Concerns historical , prehistorical and archaeological resources; applie s only to

areas owned by State or its political subdivision .

Protects animal s listed on the Colorado Division of Wildlife generated list . Coordinatio n with the Division of wildlife is strongl y urged if animal species are to

be impacted. T he Colorado Natural Areas Program maintain s a lis t of plan t species of special

concern for the State . Althoug h not protected by State statue, coordinatio n with Division of Parks and Outdoor Recreation is recommended if activities wil l impact

listed species.

Establishes regulation s for solid waste management facilities , includin g locatio n

standards .

Establishes broad citin g criteria an d site evaluation procedures for individual

storage an d disposal units (i.e., impoundments , landfills , etc.)

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TABLE F.2 POTENTIA L FEDERA L AN D STAT E ACTION-SPECIFI C ARARs

Standard, Requirement Criteria, or Limitation Citation Description

FEDERAL

Clea n Air Act

Solid Waste Disposal Act as

amended by the Resource Conservation and Recovery Act of

1976 (RCRA)

Hazardous Material s Transportatio n Act

Occupational Health an d Safet y Act

Federal Mine Safet y an d Health A ct

42 USC § 7401-7642

40 CFR 60

42 USC § 6901-6987

40 CFR 257

49 USC § 1801-1813

49 CFR 107, 171-177

29 USC § 651-678

30 USC § 800-962

Establishe s emission standards for certain categories of industrial stationar y

sources.

Establishe s criteria for determinin g which solid waste disposal facilitie s an d

practices pose a reasonable probabilit y of adverse effect s on health.

Regulates transportatio n of hazardous materials .

Regulates worker health and safety .

Establishes requirements to protect worker health and safet y in and around mines.

STATE OF COLORADO

State Solid Waste Disposal Site s

a nd Facilitie s Act

Colorado Mined Land Reclamation A ct

Colorado Air Qualit y Control Act

Colorado Noise Abatement Act

Colorado Regulaiton for the State Discharge Permit System

Regulation s on the Collectio n of Aquatic Life

6CCR 1007-2

CRS 34-32-1 01 to 125

2CCR 407-1

5CCRS 1001-1, 3, 4, 5, 8, 10

CRS 25-12-101 to 108

6.1.0, 5 CCR 1002-2

2CCR 406-8, Ch. 13, Article III , Sec . 1316

Establishes polic y for licensing, locating, constructing an d operatin g solid waste

facilities . Regulates al l aspect s of land use for mining, includin g the locatio n of minin g

operation s and related reclamation activities and other environmental and socioeconomic impacts .

Establishes emissions standards for particulate s an d lead.

Establishes maximum permissible noise level s for particular time periods and

use zones.

lan d

Establishes regulation s for stormwater runof f at construction sites.

Requirements governing the collectio n of wildlife for scientifi c purposes .

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F .4 REFERENCES

United State s Army Corps of Engineers (COE), 1985. Regulatory Program Applican t Information . EP 1145-2-1, May.

Foothill s Engineering Consultant s (FEC), 1993. Cultural Resources Survey of Proposed RI/FS Samplin g Locations in Oregon Gulch, California Gulch Superfun d Site, Lake County, Colorado. October.

R oy F. Weston, Inc. and Terra Technologies (Weston), 1995. Preliminary Ecological Risk Assessment for Oregon Gulch (OU 10). January.

Woodward-Clyde Consultant s (WWC) , 1992. Wetlands Map for California Gulch RI/FS Stud y Area. September.

Woodward-Clyde Consultant s (WWC) , 1993. Terrestrial Ecosystem Evaluation Report California Gulch Site, Leadville, Colorado. April .

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July 27, 1995 FINAL * EE/CA Garibaldi Mine Site * Appendices

APPENDIX G

COST ESTIMATE S

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California Gulch NP L Site OU-4 Engineering Evaluation/Cos t Analysi s - Garibaldi Min e Site Alternative A- Diversion Channel s

DIRECT CAPITAL COSTS

Component Unit Uni t Cost Quantity Total Cost Source

Construct Ditches Improve Access Road Riprap Haul Riprap Filter Fabric Place Riprap Concrete liner Culverts Portal work Cultural Resources Revegetation Dust Control Sedimen t Controlcu-yd

lump

cu-yd

cu-yd

sq-ft

cu-yd

sq-ft

lump

lum p

lump

acre

lum p

lum p

$25.00

$11.20

$12.60

$0.25

$15.00

$7.50

$3,000

294

193

193

7.000

193

5,497

0.2

$7,350

$10,000

$2,162

$2,432

$1,750

$2,895

$41 ,228

$8,000

$10,000

$3,000

$600

$2,000

$2,000

Idarado Costs S M I ASI-RCC, Buena Vista ASI-RCC, Buena Vista Previous Projects Idarado Costs Idarado Costs Previous Projects Previous Projects Previous Projects R BI Landscape Previous Projects Previous Projects

,co

,co

TOTA L DIRECT CAPITA L COST S $93,416

INDIREC T CAPITA L COST S

Engineering and Design (10% of Direct) Contingency (25% of Direct) Legal Fees (5% of Direct) Regulatory Cost (5% of Direct) Mobilization and Demobilization (10% of Direct) EPA Fees (20% of Engineering, 5% of Direct)

TOTA L INDIREC T CAPITA L COST S

TOTA L CAPITA L COST S

$9,342

$23,354

$4,671

$4,671

$9,342

$6,539

$57,918

$151,334

POST REMOVAL SIT E CONTROL COST S Discount 7.00% for present worth

Component Unit

Present Unit cost Each Each/yr $/year Years Worth

DIREC T OPERATION AN D MAINTENANC E Inspection hour

Erosion Repair lump Vegetation Repair lump

TOTAL

INDIRECT OPERATION AN D Administration (5% of direct) Misc. fees (5%of direct) Reserve (25% of direct)

$40.00

$2,000

$15,000

MAINTENANC E

$556

$556

$2,778

8

1

0

COST S

1

1

1

4

1

0

1

1

1

$1,280

$2,000

$0

$556

$556

$2,778

4

4

4

4

4

4

$4,336

$6.774

$0

$11.110

$1,882

$1,882

$9,408

TOTAL

OPERATION AND MAINTENANCE PRESENT WORTH ( 4 years)

$13,171

$24,281

GRAN D TOTA L $175,615
California Gulch NP L Site OU-4 Engineering Evaluation/Cost Analysi s - Garibaldi Min e Site Alternative C- Diversion Channels/Groundwater Interceptor Trench/ Regrade/Simple Cover

DIRECT CAPITA L COST S

Component Unit Unit Cost Quantity Total Cost Source

Construct Ditches Improve Access Road Riprap Haul Riprap Filter Fabric Place Riprap Concrete liner Culverts Groundwater Trench Regrade Cover Soi l Supply Cover Soil Placement Revegetation Portal work Cultural Resources Dust Control Sedimen t Controlcu-yd

lump

cu-yd

cu-yd

sq-ft

cu-yd

sq-ft

lump

each

cu-yd

cu-yd

cu-yd

acres

lump

lum p

lum p

lum p

$25.00

$11.20

$12.60

$0.25

$15.00

$7.50

$10,000

$1.00

$10.00

$1.75

$3,000

275

193

193

7,000

193

5,120

2

3,100

4,100

4,100

1.8

$6.875

$20,000

$2,162

$2,432

$1,750

$2,895

$38,400

$4,000

$20,000

$3,100

$41,000

$7,175

$5,400

$10,000

$5,000

$2,000

$2,000

Idarado Costs S M I ASt-RCC, Buena Vista , ASI-RCC, Buena Vista , Previous Projects Idarado Costs Idarado Costs Means Previous Projects Previous Projects

CO

CO

Webster Sand and Gravel Idarado Costs R BI Landscapin g Previous Projects Previous Projects Previous Projects Previous Projects

TOTA L DIRECT CAPITA L COST S $174,188

INDIREC T CAPITA L COST S

Engineering and Design (10% of Direct) Contingency (25% of Direct) Legal Fees (5% of Direct) Regulatory Cost ( 5% of Direct) Mobilization and Demobilization (10% of Direct) EPA Fees (20% of Engineering, 5% of Direct)

TOTA L INDIRECT CAPITA L COST S

TOTA L CAPITA L COSTS

$17,419

$43,547

$8,709

$8,709

$17,419

$12,193

$107,997

$282,185

POST REMOVAL SIT E CONTRO L COST S Discount 7.00% for present worth

Component Unit Unit cost Each Each/yr

Present

$/year Years Worth

DIRECT OPERATION AN D MAINTENANC E Inspection hour

Erosion Repair lump Vegetation Repair lump

TOTAL

INDIRECT OPERATION AN D Administration (5% of direct) Misc. fees (5%of direct) Reserve (25% of direct)

$40.00

$2,000

$2,400

MAINTENANC E

$962

$962

$4,810

8

1

1

COSTS

1

1

1

4

1

1

1

1

1

$1,280

$2,000

$2,400

$962

$962

$4,810

4

4

4

4

4

4

$4,336

$6,774

$8,129

$19,239

$3,258

$3.258

$16,292

TOTAL

OPERATION AND MAINTENANCE PRESENT WORTH ( 4 years)

$22,809

$42,048

GRAND TOTAL $324,233
CALIFORNI A GULC H NP L SIT E O U 4 ENGINEERIN G EVALUATION/COS T ANALYSIS - GARIBALD I MIN E SIT E WAST E ROCK REMOVAL UNIT COST DATE: 29-May-95 REMOVE$.WQ1

EQUIPMEN T REQUIRE D

-4 12 CY TRUCKS

-1 EXCAVATOR -1 DOZER -1 WATER TRUCK -1 MOTOR GRADER

PRODUCTIONHAU L TIM E RETURN TIM E FIXE D TIM E TOTA L CYCL E TIM E TRIP S PER HOUR

TRUCK CAPACIT Y R AW PRODUCTIVITY UTILIZATIO N (5 0 MIN/HR ) ADJ . PRODUCTIVIT Y FLEE T PRODUCTIVIT Y

15.0 MIN .

12.0 MIN.

5 MIN .

4 TRUCKS

32.0 MIN .

1.88 TRIPS/HOUR

12 LCY

23 LCY/HR

0.83

19 LCY/SCH HR

75 LCY/SCH HR

SCRAPER FLEET COST

EQUIPMEN T TRUCK S

EXCAVATOR DOZER MOTOR GRADER (16G ) WATE R TRUCK FORMAN AN D TRUCK

UNIT S

4

1

1

0.50

0.50

1

UNI T COST

$60.00

$90.00

$70.00

$75.00

$45.00

$32.00

TOTA L

TOTA L

COST

$240.00

$90.00

$70.00

$37.50

$22.50

$32.00

/SCH H R

/SCH H R /SCH H R /SCH H R /SCH H R /SCH H R

$492.00 /SCH HR

TOTA L UNI T COST DIRECT OVERHEAD AND PROFIT (25% of direct) TOTA L

$6.59 /LCY $1.65 /LCY $8.23 /LCY
TerraMatrix

Engineering & Environmental Services

•^BHiB^BffCTlBM

1475 Pine Grove Road • PO Box 774018 Steamboat Springs , Colorado 80477

303-879-6260 • fax 303-879-9048

Jul y 27, 1995

Ms. Denise Link

EPA Region 8, 8HWM-SR

999 18th Street , Suite 500 Denver, Colorado 80202-2405

Re: Submittal of Final Engineering Evaluation/Cost Analysis for Garibaldi Mine Site Within Upper California Gulch Operable Unit 4.

Dear Ms. Link:

On behal f of Resurrection Mining Company, enclosed are three copies of the Final EE/CA for Garibaldi Mine Site Within Upper California Gulch Operable Unit 4. Thi s final EE/CA

incorporates comments received from the public during the public comment period and provides

responses to those comments.

We will distribute copies to additional parties upon your approval. If you have any comments

or questions, please contact me.

Sincerely,

TerraM;

Alan Project

JMR:cmc

encl.

cc: Dave Baker, Resurrection Mining Company (1 copy)

Eileen Josselyn , Roy F. Weston (1 copy) T om Shepherd, Shepherd Miller, Inc. (2 copies) Bruce Featherstone, Kirklan d & Elli s (1 copy) Russ Alien, CDPHE (2 copies) Don Deere, Rocky Mountain Consultants (1 copy)

H:\664Wissub.ltr

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