Sixth Five Year Review Report for California Gulch Superfund Site Lake County Colorado


SIXTH FIVE-YEAR REVIEW REPORT FOR
CALIFORNIA GULCH SUPERFUND SITE
LAKE COUNTY, COLORADO

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Prepared by

U.S. Environmental Protection Agency
Region 8
Denver, Colorado

BETSY	Digitally signed by BETSY

SMIDINGER

SMIDINGER	Date: 2022.09.28 22:40:30 -06'00'

Betsy Smidinger, Director

Superfund and Emergency Management Division

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Table of Contents

LIST 01 ABBREVIATIONS AND ACRONYMS	viii

I.	INTRODUCTION	1

FIVE-YEAR REVIEW SUMMARY FORM	3

II.	SITEWIDE RESPONSE ACTION SUMMARY	4

Sitewide Basis for Taking Action	4

Sitewide Response Actions	5

III.	PROGRESS SINCE THE PREVIOUS REVIEW	6

IV.	FYR PROCESS	6

Community Notification, Community Involvement and Site Interviews	6

V.	0U1: YAK TUNNEL AND WTP	7

V.l 0U1: RESPONSE ACTION SUMMARY	7

Basis for Taking Action	7

Response Actions	7

Status of Implementation	8

Systems Operations/Operation & Maintenance (O&M)	9

V.2 0U1: PROGRESS SINCE PREVIOUS FYR	9

V.3 0U1: FYR PROCESS	9

Data Review	9

Site Inspection	11

V.4 0U1: TECHNICAL ASSESSMENT	11

V.5 0U1: ISSUES/RECOMMENDATIONS	12

V.6	0U1: PROTECTIVENESS STATEMENT	12

VI.	0U2: MALTA GULCH FLUVIAL TAILING/LEADVILLE CORP. MILL/MALTA GULCH TAILING

IMPOUNDMENTS	12

VI. 1 0U2: RESPONSE ACTION SUMMARY	13

Basis for Taking Action	13

Response Actions	13

Status of Implementation	14

Systems Operations/Operation & Maintenance (O&M)	14

VI.2 0U2: PROGRESS SINCE PREVIOUS FYR	15

VI.3 0U2: FYR PROCESS	15

Data Re view	15

Site Inspection	15

VI.4 0U2: TECHNICAL ASSESSMENT	15

VI.5 0U2: ISSUES/RECOMMENDATIONS	16

VI.6	0U2: PROTECTIVENESS STATEMENT	16

VII.	0U3: DENVER & RIO GRANDE WESTERN RAILROAD COMPANY (D&RGW) SLAG

PILES/RAILROAD EASEMENT/RAILROAD YARD	16

VII. 1 0U3: RESPONSE ACTION SUMMARY	17

Basis for Taking Action	17

Response Actions	17

Status of Implementation	18

Systems Operations/Operation & Maintenance (O&M)	18

VI 1.2 013: PROGRESS SINCE PREVIOUS FYR	18

VII.3 0U3: FYR PROCESS	19

Data Re view	19

Site Inspection	19

VI 1.4 0U3: TECHNICAL ASSESSMENT	19

VII.5 0U3: ISSUES/RECOMMENDATIONS	20

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VII.6	0U3: PROTECTIVENESS STATEMENT	20

VIII.	014: UPPER CALIFORNIA GULCH	21

VIII. 1 014: RESPONSE ACTION SUMMARY	21

Basis for Taking Action	21

Response Actions	21

Status of Implementation	22

Systems Operations/Operation & Maintenance (O&M)	22

VIII.2 014: PROGRESS SINCE PREVIOUS FYR	23

VIII.3 OU4: FYR PROCESS	23

Data Review	23

Site Inspection	23

VIII.4 OU4: TECHNICAL ASSESSMENT	23

VIII.5 OU4: ISSUES/RECOMMENDATIONS	24

VIII.6	OU4: PROTECTIVENESS STATEMENT	24

IX.	01.5: ASARCO SMELTERS/SLAG/MILL SITES	24

IX. 1 01.5: RESPONSE ACTION SUMMARY	25

Basis for Taking Action	25

Response Actions	25

Status of Implementation	27

Systems Operations/Operation & Maintenance (O&M)	27

IX.2 015: PROGRESS SINCE PREVIOUS FYR	28

IX.3 0U5: FYR PROCESS	28

Data Review	28

Site Inspection	28

IX.4 0U5: TECHNICAL ASSESSMENT	29

IX.5 0U5: ISSUES/RECOMMENDATIONS	29

IX.6	0U5: PROTECTIVENESS STATEMENT	30

X.	OU6: STRAY HORSE GULCH AND EVANS GULCH WATERSHEDS	30

X.l OU6: RESPONSE ACTION SUMMARY	30

Basis for Taking Action	30

Response Actions	31

Status of Implementation	32

Systems Operations/Operation & Maintenance (O&M)	33

X.2 016: PROGRESS SINCE PREVIOUS FYR	33

X.3 01 6: FIVE-YEAR REVIEW PROCESS	33

Data Review	33

Site Inspection	33

X.4 OU6: TECHNICAL ASSESSMENT	34

X.5 OU6: ISSUES/RECOMMENDATIONS	35

X.6	OU6: PROTECTIVENESS STATEMENT	35

XI.	017: APACHE TAILING IMPOUNDMENTS	35

XI. 1 OU7: RESPONSE ACTION SUMMARY	36

Basis for Taking Action	36

Response Actions	36

Status of Implementation	37

Systems Operations/Operation & Maintenance (O&M)	38

XI.2 017: PROGRESS SINCE PREVIOUS FYR	38

XI.3 OU7: FYR PROCESS	39

Data Re view	39

Site Inspection	39

XI.4 OU7: TECHNICAL ASSESSMENT	39

XI.5 OU7: ISSUES/RECOMMENDATIONS	39

XI.6	OU7: PROTECTIVENESS STATEMENT	40

XII.	018: LOWER CALIFORNIA GULCH	40

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XII. 1 0U8: RESPONSE ACTION SUMMARY	40

Basis for Taking Action	40

Response Actions	41

Status of Implementation	42

Systems Operations/Operation & Maintenance (O&M)	42

XII.2 018: PROGRESS SINCE PREVIOUS FYR	43

XII.3 OU8: FYR PROCESS	43

Data Review	43

Site Inspection	43

XII.4 OU8: TECHNICAL ASSESSMENT	43

XII.5 OU8: ISSUES/RECOMMENDATIONS	44

XII.6	OU8: PROTECTIVENESS STATEMENT	44

XIII.	OU9: RESIDENTIAL POPULATED AREAS	44

XIII. 1 OU9: RESPONSE ACTION SUMMARY	45

Basis for Taking Action	45

Response Actions	45

Status of Implementation	46

Systems Operations/Operation & Maintenance (O&M)	47

XIII.2 OU9: PROGRESS SINCE PREVIOUS FYR	48

XIII.3 OU9: FYR PROCESS	48

Data Review	48

Site Inspection	49

XIII.4 OU9: TECHNICAL ASSESSMENT	49

XIII.5 OU9: ISSUES/RECOMMENDATIONS	49

XIII.6	OU9: PROTECTIVENESS STATEMENT	50

XIV.	OU10: OREGON GULCH	50

XIV. 1 OU10: RESPONSE ACTION SUMMARY	50

Basis for Taking Action	50

Response Actions	51

Status of Implementation	51

Systems Operations/Operation & Maintenance (O&M)	52

XIV.2 OU10: PROGRESS SINCE PREVIOUS FYR	52

XIV.3 OU10: FYR PROCESS	53

Data Re view	53

Site Inspection	53

XIV.4 OU10: TECHNICAL ASSESSMENT	53

XIV.5 OU10: ISSUES/RECOMMENDATIONS	54

XIV.6	OU10: PROTECTIVENESS STATEMENT	54

XV.	OU11: ARKANSAS RIVER VALLEY FLOODPLAIN	54

XV. 1 OU11: RESPONSE ACTION SUMMARY	55

Basis for Taking Action	55

Response Actions	55

Status of Implementation	56

Systems Operations/Operation & Maintenance (O&M)	56

XV.2 OU11: PROGRESS SINCE PREVIOUS FYR	56

XV.3 OU11: FYR PROCESS	57

Data Re view	57

Site Inspection	57

XV.4 OU11: TECHNICAL ASSESSMENT	57

XV.5 OU11: ISSUES/RECOMMENDATIONS	58

XV.6	OU11: PROTECTIVENESS STATEMENT	58

XVI.	OU12: SITEWIDE WATER QUALITY	58

XVI. 1 OU12: RESPONSE ACTION SUMMARY	59

Basis for Taking Action	59

iv

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Response Actions	60

Status of Implementation	61

Systems Operations/Operation & Maintenance (O&M)	61

XVI.2 0112: PROGRESS SINCE PREVIOUS FYR	61

XVI.3 OU12: FYR PROCESS	62

Data Review	62

Site Inspection	66

XVI.4 OU12: TECHNICAL ASSESSMENT	66

XVI.5 OU12: ISSUES/RECOMMENDATIONS	67

XVI.6	OU12: PROTECTIVENESS STATEMENT	67

XVII.	NEXT REVIEW	67

Tables

Table 1: Land Use-Based Lead Remedial Goals	5

Table 2: Effluent Discharge Limits Established in the 2008 Consent Decree	8

Table 3: Protectiveness Determinations/Statements from the 2017 FYR Report	9

Table 4: Types of Contamination in Each Media for OU2	13

Table 5: Protectiveness Determinations/Statements from the 2017 FYR Report	15

Table 6: Contaminated Media, OU3	17

Table 7: Protectiveness Determinations/Statements from the 2017 FYR Report	19

Table 8: Protectiveness Determinations/Statements from the 2017 FYR Report	23

Table 9: Contaminated Medium, OU5	25

Table 10: Protectiveness Determinations/Statements from the 2017 FYR Report	28

Table 11: Contaminated Media, OU6	31

Table 12: Protectiveness Determinations/Statements from the 2017 FYR	33

Table 13: Contaminated Media, OU7	36

Table 14: Protectiveness Determinations/Statements from the 2017 FYR Report	38

Table 15: Contaminated Media, OU8	41

Table 16: Protectiveness Determinations/Statements from the 2017 FYR Report	43

Table 17: Protectiveness Determinations/Statements from the 2017 FYR Report	48

Table 18: Blood Lead Testing Results, 2017 to 2021 	48

Table 19: Contaminated Media, OU10	51

Table 20: Protectiveness Determinations/Statements from the 2017 FYR Report	52

Table 21: Protectiveness Determinations/Statements from the 2017 FYR Report	56

Table 22: Status of Recommendations from the 2017 FYR Report	57

Table 23: Contaminated Media, OU12	59

Table 24: Surface Water COC Cleanup Goals	60

Table 25: Protectiveness Determinations/Statements from the 2017 FYR Report	62

Table 26: Long-term Monitoring Requirements and Objectives	63

Table 27: Metals Concentration and CO WQS Goals in the Arkansas River, 2021 	63

Table 28: Cadmium and Zinc Exceedances Compared to ROD at POC Location AR-3A	64

Table 29: Summary of Samples Exceeding Groundwater Human Health Standards in 2021	65

Table 30: Maximum 2021 Groundwater Concentrations Compared to Human Health Standards	65

Table B-l: Site Chronology	B-Error! Bookmark not defined.

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Table B-8: Chronology of OU6 Events B-Error

Table B-9: Chronology of Initial EPA Response Actions, OU6 B-Error

Table B-10: Chronology of OU7 Events B-Error

Table B-l 1: Chronology of Removal and Remedial Actions, OU7 B-Error

Table B-12: Chronology of OU8 Events B-Error

Table B-13: Chronology of OU9 Events B-Error

Table B-14: Chronology of OUIO Events B-Error

Table B-15: Chronology of OU11 Events B-Error

Table B-16: Chronology of OU12 Events B-Error

Table C-l: Land Use-Based Lead Remedial Goals C-Error

Table C-2: Response Actions for OU9 C-Error

Table H-l: Previous and Current ARARs for OU12 Groundwater COCs H-Error

Table H-2: Yak Tunnel WTP Effluent Limits H-Error

Table H-3: Comparison of 2009 OU12 Surface Water ARARs to Current Standards H-Error! Bookmark not

defined.

Table 1-1: OU1 Bedrock Groundwater Quality at Monitoring Well BBW-5, 2007 to 20201-Error! Bookmark not
defined.

Table 1-2: Yak Tunnel Blockage Water Quality, 2007 to 2020 I-Error! Bookmark not defined.

Table 1-3: Summary of Yak Tunnel Blockage Water Pumping and Water Levels, 2020 ....I-Error! Bookmark not
defined.

Table 1-4: OUIO Groundwater Quality from Monitoring Well OG1TMW3 I-Error! Bookmark not defined.

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Figure D-l: Site Vicinity D-Error

Figure D-2: OU1 Map D-Error

Figure D-3: OU2 Map D-Error

Figure D-4: OU3 Map D-Error

Figure D-5: OU4 Map D-Error

Figure D-6: OU5 Map D-Error

Figure D-7: OU6 Map D-Error

Figure D-8: OU7 Map D-Error

Figure D-9: OU8 Map D-Error

Figure D-10: OU8 Details D-Error

Figure D-ll: OU9 Map D-Error

Figure D-12: OUIO Map D-Error

Figure D-13: OU11 Map D-Error

Figure H-l: TI Waiver Area at the Site H-Error

Figure 1-1: OU1 Monitoring Locations I-Error

Figure 1-2: OU12 Surface Water Monitoring Locations I-Error

Figure 1-3: OU12 Groundwater Monitoring Locations I-Error

Figure 1-4: OU12 Aquatic Life Monitoring Locations I-Error

Figure 1-5: Zinc Loading to the Arkansas River from Surface Water Sources at CG-6, 2019... I-Error! Bookmark
not defined.

Figure 1-6: Cadmium Loading to the Arkansas River from Surface Water Sources at CG-6, 2019 I-Error!

Bookmark not defined.

Figure 1-7: Dissolved Zinc Concentrations and Load at AR-1 and AR-3A I-Error! Bookmark not defined.

Figure 1-8: Dissolved Cadmium Concentrations and Load at AR-1 and AR-3A.. I-Error! Bookmark not defined.
Figure 1-9: Zinc Loading to the Arkansas River from Surface Water Sources at CG-6, 2021... I-Error! Bookmark
not defined.

Figure 1-10: Cadmium Loading to the Arkansas River from Surface Water Sources at CG-6, 2021 I-Error!

Bookmark not defined.

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Figure 1-11: Flow and Dissolved Zinc Concentrations at AR-3A	I-Error! Bookmark not defined.

Figure 1-12: Flow and Dissolved Cadmium Concentrations at AR-3A	I-Error! Bookmark not defined.

Figure K-l: 2009 County Institutional Control for Operable Units 3 and 8	K-Error! Bookmark not defined.

Figure K-2: 2009 County Institutional Control for 17 Mine Waste Piles Located in OU9 K-Error! Bookmark not
defined.

Figure K-3: 2010 County Institutional Control for OU9	K-Error! Bookmark not defined.

Figure K-4: 2010 County Institutional Control for OUs 4 and 7	K-Error! Bookmark not defined.

Figure K-5: 2013 County Institutional Control for OUs 2 and 5	K-Error! Bookmark not defined.

Figure K-6: 2013 City Institutional Control for OUs 3, 5, 6, 7, 8 and 9	K-Error! Bookmark not defined.

Figure K-7: 2012 Environmental Covenant for Resurrection Mining Company's Zone A properties	K-Error!

Bookmark not defined.

Figure K-8: 2012 Environmental Covenant for Resurrection Mining Company's Zone B properties	K-Error!

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Figure K-9: 2012 Environmental Covenant for Resurrection Mining Company's Zone C properties	K-Error!

Bookmark not defined.

Figure K-10: Lake County Building Permit Procedures	K-Error! Bookmark not defined.

Figure K-l 1: OU12 Institutional Control - Parkville Water Restriction on Private Wells in the Parkville Water
District	K-Error! Bookmark not defined.

Vll

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LIST OF ABBREVIATIONS AND ACRONYMS

AOC

Administrative Order on Consent

amsl

above mean sea level

ARAR

Applicable or Relevant and Appropriate Requirement

ARD

Acid Rock Drainage

AROD

ROD Amendment

ASARCO

American Smelting and Refining Company

AV

Arkansas Valley

AWQC

Ambient Water Quality Criteria

BRA

Baseline Risk Assessment

CDC

Centers for Disease Control and Prevention

CDPHE

Colorado Department of Public Health and Environment

CERCLA

Comprehensive Environmental Response, Compensation, and Liability Act

CFR

Code of Federal Regulations

COC

Contaminant of Concern

CP

Contingency Plan

CPW

Colorado Parks and Wildlife

CSU

Colorado State University

CZL

Colorado Zinc-Lead Mill

D&RGW

Denver & Rio Grande Western Railroad Company

DWR

Division of Water Resources

EE/CA

Engineering Evaluation/Cost Analysis

EGWA

Elgin Smelter, Grant/Union Smelter, Western Zinc Smelter and Arkansas Valley South Hillside



Slag Pile

EPA

United States Environmental Protection Agency

ESD

Explanation of Significant Differences

FFS

Focused Feasibility Study

FS

Feasibility Study

FTS

Fluvial Tailing Site

FYR

Five-Year Review

gpm

Gallons Per Minute

IC

Institutional Control

LCBLUD

Lake County Building and Land Use Department

LCCHP

Lake County Community Health Program

LMDT

Leadville Mine Drainage Tunnel

LMGFT

Lower Malta Gulch Fluvial Tailing

MCL

Maximum Contaminant Level

1-ig/dL

Micrograms per Deciliter

l-Lg/L

Micrograms per Liter

(j,S/cm

micro Siemens per centimeter

mg/kg

Milligrams per Kilogram

mg/L

Milligrams per Liter

MGTI

Malta Gulch Tailing Impoundment

MOU

Memorandum of Understanding

MTI

Malta Tailing Impoundment

NCP

National Oil and Hazardous Substances Pollution Contingency Plan

NPL

National Priorities List

OLEM

Office of Land and Emergency Management

OSWER

Office of Solid Waste and Emergency Response

O&M

Operation and Maintenance

OU

Operable Unit

POC

Point of Compliance

Vlll

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PRP

PWT

RAO

RCRA

RI

ROD

RMP

RPM

SDWA

SEMS

SFS

TBC

TI

UAO
UP

USBR
USGS
UU/UE
WTP

Potentially Responsible Party

Pacific Western Technologies, Ltd.

Remedial Action Objective

Resource Conservation and Recovery Act

Remedial Investigation

Record of Decision

Routine Monitoring Plan

Remedial Project Manager

Safe Drinking Water Act

Superfund Enterprise Management System

Screening Feasibility Study

To Be Considered

Technical Impracticability

Unilateral Administrative Order

Union Pacific

Unites States Bureau of Reclamation
United States Geological Survey
Unlimited Use and Unrestricted Exposure
Water Treatment Plant

IX

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I. INTRODUCTION

The purpose of a five-year review (FYR) is to evaluate the implementation and performance of a remedy to
determine if the remedy is and will continue to be protective of human health and the environment. The methods,
findings and conclusions of reviews are documented in FYR reports such as this one. In addition, FYR reports
identify issues, if any, found during the review and document recommendations to address them.

The U.S. Environmental Protection Agency (EPA) is preparing this FYR pursuant to the Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA) Section 121, consistent with the National
Oil and Hazardous Substances Pollution Contingency Plan (NCP) (40 Code of Federal Regulations (CFR) Section
300.430(f)(4)(ii)) and considering EPA policy.

This is the SIXTH FYR for the California Gulch Superfund site (Site). The triggering action for this statutory
review is the completion date of the previous FYR, September 29, 2017. The FYR has been prepared because
hazardous substances, pollutants or contaminants remain at the Site above levels that allow for unlimited use and
unrestricted exposure (UU/UE).

The FYR was led by Linda Kiefer, the EPA's remedial project manager (RPM) for the Site. Representing the state
of Colorado (State), Kyle Sandor is the project manager for the support agency, the Colorado Department of
Public Health and Environment (CDPHE). EPA contractor support was provided by Treat Suomi and Claire
Marcussen from Skeo. The review began on October 29, 2021.

The 18-square-mile Site is about 100 miles southwest of Denver, in Lake County, Colorado, in the Upper
Arkansas River watershed. (Figure D-l). The Site includes the City of Leadville, various parts of the Leadville
Historic Mining District, and a section of the Arkansas River from the confluence of California Gulch
downstream to the confluence of Two-Bit Gulch. Populated areas include neighborhoods, commercial businesses
such as restaurants and shops, and facilities for recreation, historical tourism, athletics, industrial and mining
activities. Zoned uses for the Site include industrial mining, business, recreational and residential. The Parkville
Water District supplies water to the majority of homes and businesses.

The Site consists of the following 12 operable units (OUs). This FYR Report addresses all 12 OUs (Figure D-l):

1. OU1 - Yak Tunnel and Water Treatment Plant (WTP)

2. OU2 - Malta Gulch Fluvial Tailing/Leadville Corp. Mill/Malta Gulch Tailing Impoundments

3. OU3 - Denver & Rio Grande Western Railroad Company (D&RGW) Slag Piles/Railroad

Easement/Railroad Yard

4. OU4 - Upper California Gulch

5. OU5 - American Smelting and Refining Company (ASARCO) Smelters/Slag/Mill Sites

6. OU6 - Stray Horse Gulch and Evans Gulch Watersheds

7. OU7 - Apache Tailing Impoundments

8. OU8 - Lower California Gulch

9. OU9 - Residential Populated Areas

10. OU10 - Oregon Gulch

11. OU 11 - Arkansas River Valley Floodplain

12. OU12 - Sitewide Water Quality

Former mining operations contributed to metals contamination in surface water, groundwater, soil and sediments.
The Yak Tunnel Water Treatment Plant (WTP) in OU1 primarily treats waters draining from the Yak Tunnel and
OU4 Upper California Gulch. Extensive piles of mine tailing, slag and waste rock are present on the Site;
remedial efforts at OUs 2 through 11 are designed to control these source areas.1 Water quality data are collected

1 The EPA designated OUs 2 through 11 to facilitate source remediation of specific geographic areas.

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on an ongoing basis as part of the OU12 remedy selected in 2009. The OU12 and OU6 remedies are in the
remedial action phase with expected completion dates in 2022 and 2026, respectively.

Remedies for OUs 1, 2, 3, 4, 5, 7, 8, 9, 10 and 11 have been completed. The remedies are monitored and
maintained, as required, and are performing as intended. Except for OU11, all of these OUs have been partially
deleted from the National Priorities List (NPL). The OU1 Yak Tunnel WTP continues to operate.

Remedial actions in OU6 and OU12, once fully implemented, are expected to perform as intended. Additionally,
Institutional Controls are being finalized for OU6, OU11 and OU12. OU11 entered the operation and maintenance
(O&M) phase in May 2017; this OU needs implementation of institutional controls before it can be partially
deleted from the NPL.

The EPA has determined in this FYR Report that the completed cleanup activities at the following operable
units (OUs 1, 2, 3, 4,5, 7, 8, 9,10) are protective. This means these remedies are protective of human health
and the environment. There are no unacceptable risks to human health. Exposure to contamination is being
controlled through the use of institutional controls.

• Yak Tunnel and WTP (OU 1)

o The contaminated waters that flow along and inside the Yak Tunnel are directed to a water
treatment plant that treats the water and discharges it to California Gulch.

• Malta Gulch Fluvial Tailing/Leadville Corporation Mill/Malta Gulch Tailing Impoundments (OU2)

o The contaminated soils have been excavated and the areas are covered with clean soil and
revegetated.

• Denver & Rio Grande Western Railroad Company Slag Piles/Railroad Easement/Railroad Yard (OU3)

o Fine slag was removed and capped. Use restrictions are in place to protect the cap.

• Upper California Gulch (OU4)

o Mine drainage is diverted away from the mine waste piles. Contaminated soils and mine waste
have been excavated and the areas covered with rock or clean soil and have been revegetated.

• ASARCO Smelters/Slag/Mill Sites (OU5)

o Contaminated soils and mine waste have been excavated, consolidated and capped; the areas
were covered with clean soil and revegetated.

• Apache Tailing Impoundments (OU7)

o Mine tailings have been consolidated and capped with surface water controls, and the area was
covered with clean soil or rock and was revegetated.

• Lower California Gulch (OU8)

o Mine waste and sediment were removed, drainage channels were reconstructed, excavated
areas were regraded and revegetated, and erosion controls were placed in tailings areas.

• Residential Populated Areas (OU9)

o A county health program combines blood lead monitoring, education and community

awareness, remediation when appropriate, and advises residents on how to reduce the potential
exposure to lead in Leadville.

• Oregon Gulch (OU 10)

o Contaminated sediment and soil from the channel and floodplain have been removed to the
tailing impoundment and covered, erosion has been controlled, and the leachate is managed by
the Yak Tunnel Water Treatment Plant.

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For the completed cleanup activities at OU11 and OU12, the remedies are short-term protective.

• Arkansas River Valley Floodplain (OU11)

o Soil in ranches in the floodplain was amended to change the pH and was revegetated.
Contaminated waste transported along the river has been treated or stabilized. Institutional
controls are under consideration in the event of the land-use change.

• Sitewide Water Quality (OU12)

o Surface water shows that water quality standards in the Arkansas River at the point of
compliance are being met. There is a technical impractablity waiver for groundwater that
cannot meet standards. In addition, restrictions are in place to limit people coming into contact
with groundwater contamination. The EPA and CDPHE are evaluating if additional restrictions
are necessary to limit people coming into contact with groundwater contamination.

Completed and future cleanup activities at OU6 Stray Horse Gulch and Evans Gulch Watersheds will be
protective once complete. The protection of human health and the environment is achieved by capping several
waste rock piles and diverting water away in channels from acidic waste rock piles, and/or containing
contaminated surface waters in a series of retention ponds; some waters are diverted for treatment at the U.S.
Bureau of Reclamation (USBR) Leadville Mine Drainage Tunnel Treatment Plant. The area is zoned
Industrial/Mining. Institutional controls are under consideration in the event of land-use changes and to protect
engineered remedies.

FIVE-YEAR REVIEW SUMMARY FORM

SITE IDENTIFICATION

Site Name: California Gulch

EPA ID: COD980717938

Region: 8

State: Colorado

City/County: Leadville/Lake

NPL Status: Final

Multiple OUs?

Yes

Has the Site achieved construction completion?

Lead agency: EPA

Author name: Linda Kiefer, with additional support provided by Skeo

Author affiliation: EPA Region 8

Review period: 10/29/2021 - 8/31/2022

Date of site inspection: 6/16/2022

Type of review: Statutory

Review number: 6

Triggering action date: 9/29/2017

Due date (fiveyears after triggering action date): 9/29/2022

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II. SITE WIDE RESPONSE ACTION SUMMARY

Sitewide Basis for Taking Action

The Site has been the location of mining, mineral processing and smelting activities that have produced gold,
silver, lead and zinc for more than 140 years. Numerous mining methods generated several types of waste: waste
rock piles, mill tailings, slag and other smelter waste, and acid rock drainage (ARD).

Prior to listing the Site on the NPL, the EPA, the United States Geological Survey (USGS) and private parties
conducted groundwater and surface water studies. The EPA added the Site to the NPL in 1983 due to the impact
of heavy metals in soils and waste rock on humans, and mine drainage on surface waters in California Gulch and
the Arkansas River. The initial Phase I sitewide remedial investigation (Phase I RI) was completed in May 1987.
The report indicated that surface water in California Gulch exceeded primary drinking water standards for lead
and cadmium and that the site surface water contained cadmium, copper, lead and zinc at levels that exceeded
water quality criteria. In addition, soils and groundwater contained elevated levels of arsenic, zinc, lead, copper
and cadmium. Subsequent remedial investigations and feasibility studies (RI/FSs) occurred throughout the early
1990s. The overall site chronology is presented in Table B-l.

Baseline risk assessments (BRAs) characterized risks to human and ecological receptors at the Site; risk-based
numerical cleanup goals were also established based on land use. A summary of site risks and numerical cleanup
goals is below. Appendix C discusses the BRAs in more detail.

Under the Site's 1994 Consent Decree with Asarco Inc, Leadville Corp., Apache Energy, Resurrection Mining,
Newmont Corp., and the Res-Asarco Joint Venture, assessment of sitewide surface water and groundwater quality
was deferred to OU12. The EPA issued a Record of Decision (ROD) for OU12 in September 2009. Remedial
action activities are near completion to address contaminated surface water and groundwater with the completion
of the remedial action anticipated by September 2022. Site risks and associated numerical cleanup goals
applicable to OUs 2 through 11 are limited to soils, sediments and mine wastes (solid media).

Human Health Risks

The BRAs led to the conclusion that non-lead metals in surface soils and groundwater do not pose a significant
health risk to residents. Thus, the only contaminant of concern (COC) for human health in soil is lead. To evaluate
risk, calculations were performed to identify concentrations (action levels) of lead in soil that were of potential
concern.

The EPA's 1996 risk assessment for lead was supported by a large body of site-specific data that included not
only extensive measurements of lead in soil and dust in residential locations, but also an extensive demographics
survey, data on lead levels in water and paint (both interior and exterior), data on the physical and chemical forms
of lead at various locations around the community, and an informative, community-wide, blood lead study
involving 314 children (about 65% of the total population of children living at the site). These data supported two
parallel lines of investigation and assessment using the EPA's Integrated Exposure Uptake and Biokinetic
(IEUBK) model to calculate the expected impact of lead levels in soil and dust on blood lead levels in area
children. The second approach compared the measured blood lead values in area children with relevant national
blood lead statistics in order to help evaluate the current effects of actual site exposure to lead.

The main findings, as exactly written in the 1999 OU9 ROD, of the 1996 lead risk assessment for the residential
children are listed below.

1. In 1991, geometric mean blood lead levels in children living within the site boundaries were typically
around 5-6 (ig/dL, which was about 1-1.5 (ig/dL higher than reported geometric mean values for children
of similar age and sex living in other areas across the nation.

2. In 1991, the site-wide frequency of children exceeding the CDC's health-based blood lead target of 10
(ig/dL was about 8%, which is slightly higher than the target of no more than. 5% above 10 (ig/dL. This
was indicative of a situation which exceeded EPA's goal of no individual child or group of similarly
exposed children having a greater than 5% chance of exceeding a blood lead level of 10 (ig/dL. In some

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sub-areas of the site, the risk of exceeding 10 (ig/dL appeared to be substantially higher (10%-25%) than
the site-wide average. Additional blood lead data collected by county health agency from more than 100
children per year for each year between 1991 and the present suggests that the incidence of children in the
community with blood lead levels above 10 (ig/dL is continuing to fluctuate between 6% and 9%.

3. There is a statistically significant correlation between lead levels ranging from 3,000 mg/kg to 3,500
mg/kg in soil and dust and elevated blood lead levels in children.

4. Both interior and exterior leaded paint contribute to risk of elevated blood lead levels in children, mainly
by adding to the concentration of lead in soil and/or dust in those homes where lead-based paint is a
potential source of lead exposure.

5. The results of the IEUBK model run using default soil and dust ingestion rates predicted blood lead levels
that were higher than observed. It was concluded that soil and dust ingestion rates in this community were
probably somewhat lower than the national average values, possibly because the ground is frozen or
snow-covered approximately eight months out of the year. Local efforts to minimize lead exposure
through an extensive education and intervention program might also explain some of the variation in
predicted versus currently observed blood lead levels.

6. Based on the analyses conducted, the risk assessment reached the conclusion that soil lead is a relatively
minor source of exposure allocations where lead levels were less than about 1,000 mg/kg. Exposure via
soil probably did not become a dominant source of exposure until lead levels were above the range from
3,000 mg/kg to 3,500 mg/kg. Other sources of lead contributing to current exposure included interior and
exterior paint and indoor dust. Lead levels in the water supplied by the municipal water system are not of
concern, but lead levels in some portions of the shallow aquifer are high enough that it would not be safe
to use that groundwater as a routine source of drinking water.

Based on these results, the EPA developed the land-use-based, lead-remedial goals for soil (Table 1).

Table 1: Land-Use-Based, Lead-Remedial Goals for Soil

l.\|)dNurc-Sccn;irid-|};isc(l
Komodiiilioii (.(i;ils

I.;iml-l se-li;ised l.oiid RciiudLiI
(.(i;ils (inii/kii)'

Reference

Recreational

16,000

BRA PartC, 1995

Worker

6,100 - 7,700 (plausible action levels)

BRA PartC, 1995

Residential

3,500

BRA Part A, 1996 and OU9
ROD

Notes:

1. Remedial goal is associated with child exposures resulting in that no more than five percent of all
children (age 0 to 72 months) who live at this site, either now or in the future, will have blood lead
values higher than 10 ng/dL blood lead level.

Ecological Receptor Risks

The 1995 Aquatic Ecological Risk Assessment evaluated risks both to terrestrial and aquatic receptors. Terrestrial
receptors included plants irrigated with contaminated surface water and herbivores that ingested contaminated
plants and soil. Historical irrigation activities resulted in risk associated with both ecological receptor pathways.

Contamination flowing downstream from California Gulch had adversely affected the Upper Arkansas River for
aquatic receptors, with impacts most severe at the confluence and dissipating with distance downstream. Yak
Tunnel WTP operations, beginning in 1992, improved water quality conditions within the first two years of
operation. However, metals were still present at levels of concern. Zinc presented the greatest hazard for aquatic
receptors, while levels of cadmium, copper and lead presented lower risks than zinc. Appendix C provides more
details on ecological receptor risks.

Sitewide Response Actions

Response actions and status of implementation for each OU are discussed in sections V through XVI below.

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III. PROGRESS SINCE THE PREVIOUS REVIEW

Progress since the 2017 FYR, protectiveness determinations from the 2017 FYR Report, and the status of
recommendations from the 2017 FYR Report will be discussed below, within each individual OU.

IV. FYR PROCESS

Community Notification, Community Involvement and Site Interviews

On May 12, 2022, the EPA published a public notice in the Herald Democrat (Appendix E), announcing
commencement of the FYR process for the Site, providing contact information for EPA RPM Linda Kiefer, and
inviting community participation in the FYR process. No one contacted the EPA or CDPHE as a result of this
advertisement. The EPA contacted several public officials and known interested parties in Leadville/Lake County.

Staff from Newmont Mining Company, parent company of the Resurrection Mining Company
(Newmont/Resurrection), that manage OUs 1, 4, 8 and 10, completed an emailed interview questionnaire on July
7, 2022. The staff indicated that operations and maintenance activities have been performing well; the Arkansas
River, the primary receiving body for any environmental impacts from the Site, is as healthy as it has been in
modern history. The staff also reported that contaminant levels in the water drainage have largely remained the
same or are trending generally down and vary with seasonal precipitation. Regardless of those variations, the
treatment systems in place continue to produce high-quality effluent that meets the discharge standards. The staff
stated that equipment at the water treatment plant and associated conveyance systems are regularly evaluated,
upgraded and/or replaced.

Newmont/Resurrection staff reported that, in comparison with the 1980s, the Arkansas River runs much cleaner,
and the community increasingly looks at the river as a recreational and economic resource. In addition, the staff
reported that reuse activities continue, largely in the form of new trail easements and recreational access.

Newmont/Resurrection has not received any complaints or inquiries from the community about environmental
issues or the remedial action-. They stated that the EPA RPM keeps them well informed regarding site activities
and remedial progress.

Several local officials and residents were invited to participate in an interview and did not voice any concerns
about the Site.

The Site's information repository is available in an online format, which allows the EPA to make information
available to the public more efficiently and conveniently.2

Site Inspection

The Site inspection took place on June 16, 2022, to evaluate the remedies at all OUs. In attendance were EPA
Region 8 RPM Linda Kiefer, Kyle Sandor with CDPHE, and Treat Suomi from EPA contractor Skeo. In addition,
Timothy Runnells with Engineering Analytics, a contractor representing New mont/Resurrection. and William
Santos with Newmont/Resurrection attended the inspection for OUs 1, 4, 8 and 10. The purpose of the inspection
was to assess the protectiveness of the remedy.

EPA RPM Linda Kiefer led the site inspection, with contractor support provided by Skeo. The inspection focused
on reviewing the conditions of capped waste piles, impoundments, diversion structures and engineering controls.
It also included observation of OU9 removal actions completed during the last five years. The inspection also
included viewing of several segments of the Arkansas River (OU11) downgradient. In addition, throughout the

2 On March 18, 2013, the EPA promulgated a final rule to amend 40 C.F.R § 300.805(c) of the NCP "Location of the
Administrative Record File" to acknowledge advancements in technologies used to manage and convey information to the
public. This enabled the EPA to make Administrative Records available to the public via the internet. Also, EPA Region 8
provides space for the public to view records related to Superfund work at the Superfund Records Center by appointment
located at 1595 Wynkoop Street in Denver. Colorado 80202-1129.

6

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inspection, monitoring well locations and several surface water monitoring locations were observed as part of
sitewide OU12. Newmont/Resurrection representatives provided site inspection tours of the Yak Tunnel WTP
(OU1), followed by inspections of OUs 4, 8 and 10.

Sections V through XVI below provide details on the site inspection for each OU. The site inspection checklist
and photographs are provided in appendices F and G, respectively. Data review is included below.

V. OU1: YAK TUNNEL AND WTP

OUl consists of the Yak Tunnel and WTP. The Yak Tunnel was constructed to dewater mines and to facilitate
mineral exploration and development. The EPA estimated that 60,000 feet of tunnels and major laterals and 55
million cubic feet to 74 million cubic feet of void space are associated with the tunnel-mining activities.

At the time of the ROD in March 1988, studies indicated that a combined total of 210 tons per year of cadmium,
lead, copper, manganese, iron and zinc were discharged from the Yak Tunnel into California Gulch, which drains
into the Arkansas River. Surface water contamination is the major impact of the Yak Tunnel discharge. Shallow
alluvial groundwater and stream sediment may have been impacted by historical releases from the Yak Tunnel.

The Yak Tunnel and Yak Tunnel WTP are located southeast of Leadville (Figure D-2).

V.l OUl: RESPONSE ACTION SUMMARY

Basis for Taking Action

Based on the results of the 1987 OUl RI/FS, the EPA determined that surface water, groundwater and sediment
remediation would be required for the protection of human health and the environment. Metals, including copper,
zinc, cadmium and lead, from former mining activities had contaminated surface water, shallow alluvial
groundwater and stream sediments at OU 1. The surface water exposure pathway was identified as the principal
pathway of concern to both human health and the environment to be addressed under OU 1. Appendix B (Table B-
2) provides a chronology of OUl events.

Response Actions

The EPA completed an FS Report in June 1987 and a Proposed Remedial Action Plan for the Yak Tunnel in
August 1987. The EPA issued a Unilateral Administrative Order (UAO) to ASARCO Incorporated, Newmont
Mining Corporation, Res-ASARCO Joint Venture and Resurrection Mining Company on March 29, 1989, for the
remedial design and remedial action of the Yak Tunnel. Two amendments were made to the UAO, on April 30,
1993, and June 16, 1993.

The remedies for the Yak Tunnel were selected initially in the 1988 OU 1 ROD, changed in the 1989 ROD
Amendment (AROD), and further altered in the 1991 and 2013 Explanation of Significant Differences (ESDs).

The remedial action objective (RAO) stated in the 1988 OUl ROD is to decrease the release and threatened
release of hazardous substances, pollutants and contaminants from the Yak Tunnel into California Gulch. The
AROD and ESDs did not change the site RAO.

The selected remedy included: (1) Construction of a single surge pond as a permanent part of the remedy; (2)
Construction of a flow-control bulkhead within the tunnel to prevent surges; (3) Identification of ground water
flow direction and potential gradient reversal as an additional element of the monitoring plan; (4) Placement of six
or more weirs, or other flow-measuring devices, at key locations in the Yak Tunnel; (5) Periodic inspection of the
Yak Tunnel and (5) Development and implementation, as necessary, of a contingency plan to address any adverse
effects on surface water or groundwater resulting from tunnel blockage. The 2013 ESD called for institutional
controls to reduce or control human exposure to contaminants of concern and to maintain the integrity of and
prevent disturbances to engineered features or structures established as part of the current remedy or future
remedies.

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The cleanup goals identified for OU1 are the effluent discharge limits for Outfall 001A presented in Table 2, as
required by the 2008 Consent Decree. In addition, semi-annual whole effluent acute toxicity tests are required,
alternating between aquatic invertebrates and fathead minnow at each semiannual test.

Table 2: Effluent Discharge Limits Established in the 2008 Consent Decree

(¦<>(¦

i niiKMil Discliiiruo l imit (uii/l.)

30-d;i\ A\er;iiie

l)iiil\ Miixiiiiiiin

Cadmium (total recoverable)

100

Copper (total recoverable)

150

300

Mercury (total recoverable)

Lead (total recoverable)

300

500

Zinc (total recoverable)

750

1,500

Notes:

|ig/L = micrograms per liter

Source: 2008 Consent Decree, Appendix A, Table 1.

Status of Implementation

The EPA released a Proposed Remedial Action Plan for the Yak Tunnel in August 1987. The EPA issued a UAO
to ASARCO Incorporated, Newmont Mining Corporation, Res-ASARCO Joint Venture and Newmont/
Resurrection in March 1989 for the Yak Tunnel's remedial design and remedial action. The EPA made two
amendments to the UAO on April 30, 1993, and June 16, 1993.

Construction of a surge pond and permanent WTP began in September 1988 and finished in June 1991. The
construction efforts included four main elements: a surface water conveyance system, the surge pond itself, a
barge transfer system and gravity filters. The Yak Tunnel WTP has been in operation since construction finished
in February 1992.

The Yak Tunnel Bulkhead, constructed in 1994, controls surges of water coming from the Yak Tunnel,
particularly during spring melt. The bulkhead is located about 1,680 feet into the tunnel from the portal.
Additionally, removal actions in OU4 and OU6 in 1990s reduced metals loading into the Arkansas River from
ephemeral tributaries.

Beginning in May 2002, increasing water levels were observed at piezometer BBW-5 and monitoring well BBW-
10. The rise in groundwater elevations occurred concomitantly with the recovery of groundwater levels in the
Black Cloud Mine workings above the 1330 Lateral level and indicated that a blockage existed in the upper
region of the Yak Tunnel downgradient of the 1330 Lateral. A water level control program was implemented in
2005 and 2006 to control the rise of Yak Tunnel blockage water levels. The water level control program consists
of groundwater pumping from behind the blockage and conveyance of this water to the Yak Tunnel WTP for
treatment and discharge. Pumping of the Yak Tunnel blockage water from the Black Cloud began on March 21,
2006. Periodic shutdowns occur for maintenance, replacement or WTP treatment management of other water
sources. Yak Tunnel blockage water levels have dropped during pumping and risen during shutdowns.

Environmental covenants on Newmont/Resurrection's properties with OU1 remedy features were recorded with
the Lake County Clerk and Recorder's Office on July 31, 2012, and October 1, 2012. These covenants are
working as designed; they restrict land-use activities and protect remedy components (Appendix K). These
controls restrict the use of untreated groundwater and protect remedial components. In addition to the
environmental covenants, OUl's industrial mining zoning designation limits land-use changes without Lake
County approval and EPA and CDPHE notification of such proposed changes. All remedial components
described in the OU1 ROD, as amended, are in place and all institutional controls are in place.

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Systems Operations/Operation & Maintenance (O&M)

The 2008 Routine Monitoring Plan (RMP), Contingency Plan (CP) and the OU1 Work Plan govern the long-term
implementation of the OU1 remedy, consistent with the terms of the 2008 Consent Decree by and among the
United States, the State and Newmont/Resurrection, to which the RMP, CP and OU1 Work Plan are appended.

Routine O&M activities include repairing grouted areas of structures due to corrosion, settlement or other factors;
occasional repair or replacement of monitoring well pumps and surface water monitoring equipment; repair of
access roads; routine repair or replacement of pumps, motors, mixers, piping and tankage; and inspections.
Resurrection submits monthly progress reports to the EPA and CDPHE that also summarize discharge monitoring
results. Resurrection also submits annual reports to the EPA and CDPHE that summarize the routine and
enhanced monitoring activities; Yak Tunnel bulkhead data including water levels, flows, and water quality data;
bedrock groundwater levels and quality and Yak Tunnel blockage pumping data.

A series of upgrades and preventative maintenance took place at the Yak Tunnel WTP during this FYR period.
Work at the Yak Tunnel has focused on creating a plan that allows for routine and regular upgrades and
improvements.

In a letter dated October 2, 2014, the EPA allowed a temporary modification to the Work Plan for the effluent to
be discharged from the Yak Tunnel WTP at a more alkaline pH, which is above the previously permitted
maximum level. This temporary modification expanded the upper value of the 30-day average pH range to 11.0.
Newmont/Resurrection can eliminate the addition of sulfuric acid post treatment, a step required to bring plant
effluent within its previous permitted upper value of the pH range to 9.0. This temporary modification of the 2008
Consent Decree Work Plan's effluent limitation was initially a 30-month trial program. Furthermore, in March
2018, this modification became permanent (SEMS#100011451). Effluent data collected during this FYR period
show that OU1 discharge has not exceeded the effluent limits.

Well BBW-5 was not sampled in June 2020 due to pump failure. A new pump was installed, and the well was
sampled in October 2020. Also, water quality samples could not be taken at BBW-10 beginning in 2012 due to
the pump failing and being lodged in the well casing. Multiple attempts were made to dislodge the pump, but they
were not successful. A contractor mobilized to the Site in 2016 and, after inspection of the well, declined to
attempt removal of the pump. Instead, a replacement well was begun in late 2019. However, well installation
stopped due to several large snowstorms and then there were delays due to the COVID-19 public health
emergency. In June 2022, both BBW-5 and BBW-10 were replaced with new wells.

V.2 OU1: PROGRESS SINCE PREVIOUS FYR

This section includes the protectiveness determinations and statements from the 2017 FYR Report (Table 3).
There were no recommendations identified from the 2017 FYR Report.

Table 3: Protectiveness Determinations/Statements from the 2017 FYR Report

()l #

PmU'iiiteiiess
lk'Urniin;i(ion

Pmlecliu'iiess M;iU-im-nl

Protective

The OU 1 remedy is protective of human health and the
environment. The RAOs are being met; contaminated waters
draining from the Yak Tunnel are directed to and treated at the
Yak Tunnel WTP before discharging the effluent to surface
water. Institutional controls have been implemented.

V.3 OU1: FYR PROCESS

Data Review

Resurrection collects the following data to determine the status of the Yak Tunnel hydrologic system and
determine if any changes are warranted to optimize the system:

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1) Water level elevations behind the Yak Tunnel bulkhead, in monitoring wells and piezometers and mine
shafts

2) Yak Tunnel flow and pump rates

3) Piezometer (BBW-7 and BBW-8) and monitoring well field parameter measurements and water quality
(BBW-1 through BBW-4 every five years)

4) Yak Tunnel blockage field parameter measurements and water quality analyses

5) Field and water quality parameters in monitoring well BBW-5 and BBW-103 and the Yak Tunnel (semi-
annual sampling event).

OU-1 monitoring locations are presented in Figure 1-1. A water level control program was implemented to control
the rise of Yak Tunnel blockage water levels. The water level control program consists of groundwater pumping
from behind the blockage and conveyance of this water to the Yak Tunnel WTP for treatment and discharge.
Pumping has continued since March 2006 (with periodic shutdowns for maintenance, replacement or WTP
treatment management of other water sources), and Yak Tunnel blockage water levels have dropped as a result.
At the historically high groundwater elevation, the groundwater elevation data continued to indicate a hydraulic
gradient toward the Yak Tunnel. Therefore, no reversal of the hydraulic gradient away from the Yak Tunnel or
adverse groundwater quality conditions are expected away from the Yak Tunnel, as long as the groundwater
elevation remains below the historically high groundwater elevation. The groundwater elevation data continued to
indicate a hydraulic gradient toward the Yak Tunnel during this FYR period.

Water quality sampling occurs semi-annually in bedrock monitoring well BBW-5 (monitoring groundwater in the
upper portion of the Yak Tunnel behind the Yak Tunnel blockage) to assess bedrock groundwater quality
conditions and identify any adverse water conditions. The monitoring wells have been placed along faults that are
known or thought to connect hydraulically with the Yak Tunnel. The 2020 Annual Monitoring Report for OU1,
published in March 2021, concluded that, overall, the 2020 water quality data from BBW-5 and the Yak Tunnel
did not show significant adverse changes from historical data collected from 2007 through 2019 (Table 1-1 and
Table 1-2, respectively). The October 2020 sample collected from the Yak tunnel blockage showed several
analytes at the higher end of historical concentrations (aluminum, arsenic, cadmium, copper, iron, lead,
manganese, magnesium, silica, specific conductance and zinc) (Table 1-2). The PRP reports that this could
potentially be due to the significant decrease in water levels at the blockage in 2020 due to consistent pumping.
The PRP continues to collect water quality samples and will determine if the trend continues or whether the
concentrations remain within historical ranges. Overall, the 2020 water quality data from the Yak Tunnel
blockage show no significant changes from historical data.

The Yak Tunnel flow rate at the bulkhead does not represent free-flowing conditions because water is impounded
behind the bulkhead and a blockage. The reason for the changes in the Yak Tunnel flow rate are not known
though they may indicate changes to the blockage or may be related to plugging of the bulkhead intakes or pipes.
Monthly average flow rates from the Yak Tunnel ranged from 128 gallons per minute (gpm) in October 2020 to a
maximum of 380 gpm in July 2020. The flow from the Yak Tunnel bulkhead was consistent with seasonal trends
of flows observed since the determination of the Yak Tunnel blockage. Flows from 2014 to 2020 have been
higher than historical flows, but precipitation from 2013 to 2017 and in 2019 has also been higher than the 19-
year average.

The Yak Tunnel blockage pumping system consists of the blockage pump, currently located in the Black Cloud
shaft to dewater the mine pool backed up by the blockage. Pumping of the Yak Tunnel blockage water from the
Black Cloud Shaft began in 2006. The historical high (i.e., pre-2006) groundwater elevation within the Yak
Tunnel blockage of 10,685 feet above mean sea level (amsl) was reached at the Black Cloud Shaft prior to the
initiation of pumping in March 2006. Pumping has continued since March 2006, with periodic shutdowns for
maintenance, replacement or WTP treatment management of other water sources, and Yak Tunnel blockage water
levels have dropped during pumping and risen during shutdowns. Table 1-3 provides a summary of pumping for
each month from January 1, 2020, to December 31, 2020, and includes cumulative volume pumped, groundwater

3 BBW-10 has not been sampled since 2012 due to blockage, and a replacement well was not installed and developed in time
to provide data for this FYR.

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elevation in the Black Cloud Shaft, the estimated water-level elevation above the Yak Tunnel blockage, and the
estimated change in water level behind the Yak Tunnel blockage. The groundwater elevation in the Yak Tunnel
blockage was 10,666 feet amsl in December 2019 and 10,639 feet amsl in December 2020. The water level
elevation behind the blockage did not exceed the 10,684-foot amsl performance standard identified in the 2008
O&M Plan.

Water discharged from the Yak Tunnel WTP goes directly to Upper California Gulch surface water and is
required to meet the EPA's surface water quality standards established in the 2008 Consent Decree. Effluent
waters are sampled before being discharged from the plant. The EPA monitors the effluent results monthly. No
exceedance of surface water quality standards was detected in discharged effluent from the Yak Tunnel WTP
during this FYR period, based on the information accessed for the Yak Tunnel WTP discharge under permit
COU000099.4

Site Inspection

The OU1 site inspection took place on June 16, 2022. Participants are listed in Section III of this FYR
Report. The Newmont/Resurrection's contractor, Tim Runnells and Will Santos, the Plant Manager, led the
inspection of the treatment system, the Yak Tunnel portal and the surge pond. Since 2014, the EPA approved a
request to temporarily allow for the effluent to be discharged at a pH above the previously permitted level. In
2018, the pH change was made permanent.

Site inspection participants noted that the plant was in good working operation at the time of the
inspection. Significant upgrades to the plant have occurred since the previous FYR, including new hardware and
software, ongoing rewiring of all electrical conduits and treatment system improvements, and a new surge pond
and barge. In addition, two wells used for routine water quality and water level measurements in the Yak Tunnel
are in the process of being replaced. All required documents, including safety and O&M guides, were available in
the plant's command station. Photographs were taken of site features, including the Yak Tunnel WTP (Appendix
G). An inspection checklist has been completed. It is available in Appendix F.

V.4 OU1: TECHNICAL ASSESSMENT

QUESTION A: Is the remedy functioning as intended by the decision documents?

The site inspection and the review of documents, applicable or relevant and appropriate requirements (ARARs),
and risk assumptions indicate that the Site's OU1 remedy has been fully implemented and is functioning as
intended by site decision documents. Construction of the Yak Tunnel WTP and support structures was completed
in 1992. The plant has operated continuously since that time, with the exception of being taken offline for routine
maintenance and repairs. Technological and equipment improvements as well as preventative maintenance have
been made at the plant during the current FYR period.

Waters flowing from the Yak Tunnel continue to be a potential source of contamination. If left untreated, the
waters would adversely affect water quality in the Arkansas River. Thus, it is important to continue the treatment
and monitoring of these waters and ensure that the hydraulic gradient is maintained towards the Yak Tunnel
through pumping. Under the 2008 Consent Decree, Newmont/Resurrection agreed to operate and maintain the
OU1 remedy features. On July 29, 2013, the EPA signed an ESD clarifying that institutional controls are required.
All institutional controls required by site decision documents are in place, as are procedures to notify the EPA and
CDPHE should local governments approve a change in land use. Environmental covenants on
Newmont/Resurrection's properties with OU1 remedy features were recorded with the Lake County Clerk and
Recorder's Office on July 31, 2012, and October 1, 2012. These covenants are working as designed; they restrict
land use activities and protect remedy components. The Yak Tunnel WTP, including the surge pond, is enclosed

4 Accessed results for 2017 to 2021 for permit COU00009 at https://echo.epa. gov/tools/data-downloads/icis-npdes-dmr-and-
limit-data-set. Accessed 6/2/2022.

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within secured and signed perimeter fencing. The Yak Tunnel portal discharges via piping that carries the
discharge directly to the WTP. The EPA partially deleted 0U1 from the NPL in April 2016.

QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of the
remedy selection still valid?

QUESTION C : Has any other information come to light that could call into question the protectiveness of the
remedy?

No additional information has come to light that would call into question the protectiveness of the remedy.

V.5 OU1: ISSUES/RECOMMENDATIONS

Issues/Recommendations

Ol (s) without Issues/Reconinieiuhlions Identified in (ho I YR:

OU1

V.6 OU1: PROTECTIVENESS STATEMENT

Operable Unit:
1

Protectiveness Statement(s)

Protectiveness Determination:
Protective

The OU1 remedy is protective of human health and the environment. The RAOs are being met;
contaminated waters draining from the Yak Tunnel are directed to and treated at the Yak Tunnel WTP,
before discharge of the effluent to surface water. Institutional controls have been implemented.

VI. OU2: MALTA GULCH FLUVIAL TAILING/LEADVILLE CORP.
MILL/MALTA GULCH TAILING IMPOUNDMENTS

OU2 is located southwest of Leadville (Figure D-3). It consists of three waste features: the Malta Tailing
Impoundment (MTI), the Malta Gulch Tailing Impoundments (MGTI) and the Lower Malta Gulch Fluvial
Tailings (LMGFT).

The MTI consists of three small impoundments occupying 4.6 acres and estimated to contain about 10,000 cubic
yards of waste. Leadville Silver & Gold constructed the MTI for wastes from a pyrite recovery process mill that
operated from 1983 to 1988. Since 1995, the LMGFT no longer exists since it was moved under a removal action
and deposited into the MGTI. The MGTI and the MTI both contain consolidated mining waste and are currently
capped and re vegetated.

The Stringtown Mill Area of the Leadville Mining Area District, which includes the MGTI, was developed
between 1879 and 1882 as a large group of placer claims. The MGTI is about 23 acres in size, is located at the
upper end of Malta Gulch and contains an estimated 1.5 million tons of waste. Ore and Chemical Company
created the first tailings impoundment as part of a sink-float mill that operated from 1943 to 1946. Hecla Mining
Company (Hecla), in conjunction with Day Mines (Day), leased the property for disposal of tailings generated
from its milling of ores from the Sherman Mine, a silver mine in a dolomite formation. Leadville Corporation

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purchased the 0U2 property in 1968 and leased it to Hecla until 1987; Hecla later purchased Day Mines
(Hecla/Day). The MGTI, in its present configuration, was constructed in 1974 by Hecla/Day. During its
leasehold, Hecla/Day operated an on-site flotation mill, while the Leadville Corporation refitted the mill to use a
cyanide leaching process, adding additional tailings to the impoundments in 1988. On November 17, 2005, the
Colorado Division of Reclamation, Mining and Safety initiated bond forfeiture with the permittee, Leadville
Corporation, for the reclamation of OU2 facilities operated under the permit.

Lower Malta Gulch is located directly downstream of the MGTI. Fluvial tailings are the tailings that have been
washed downstream of the impoundments. When Ore & Chemical Company operated the mill, the LMGFT
impoundments were not entirely effective for containment; about 600,000 tons of the tailings washed or flowed
down Lower Malta Gulch. The LMGFT is about 26 acres in size. It consisted of fluvial tailings deposits with an
estimated volume of 30,000 cubic yards.

VI.1 OU2: RESPONSE ACTION SUMMARY

Basis for Taking Action

In September 1991, the EPA and Hecla/Day signed an Administrative Order on Consent (AOC) for the
performance of an engineering evaluation/cost analysis (EE/CA) at the MGTI. Its purpose was to determine the
nature and extent of releases and to determine an appropriate response action. Based on the results of the Site's
1993 EE/CA, the EPA determined that principal threats at OU2 were: 1) the potential for casual use through direct
contact with the tailings materials, which are contaminated with heavy metals; and 2) the potential release of
heavy metals, cyanide and sulfates to groundwater as a result of precipitation events. Table 4 lists the types of
contamination found in the different media at OU2. Appendix B (Table B-3) provides a chronology of OU2
events.

Table 4: Types of Contamination in Each Media for OU2

Modiii

Coiiiiiiniiiiiiioii

Tailings impoundments

Elevated lead and zinc

Fluvial tailings

Elevated lead

Response Actions

The EPA entered into agreements in January 1993 with Hecla/Day and Leadville Silver & Gold to define the
extent of the companies' liability in paying for cleanup at the MGTI and the MTI. Under a subsequent partial
Consent Decree between the EPA and Hecla/Day, money was set aside for the OU2 cleanup. An August 1994
Consent Decree allowed the United States, as a successor to the Ore and Chemical Company, to settle the
company's liabilities at the LMGFT.

Four removal actions took place at OU2 (Table B-4). Beginning in 1995, the fluvial tailings were excavated from
LMGFT and deposited in the MGTI. The excavated area was revegetated. Four check dams and a runoff control
berm were constructed between the upper and lower portions of Malta Gulch. Confirmation sampling showed that
the excavation and removal had lowered lead levels to below the Site's residential cleanup level. Monitoring in
1997 and 1998 verified that the revegetation was successful; therefore, no further monitoring was required for this
area. The material in the MGTI was consolidated, graded, capped and revegetated. Forty-two drums, some very
corroded, were removed from the Leadville Corporation Mill and disposed of appropriately. The 1996 removal
action at the MTI consolidated the tailings, neutralized acidic leachate, and capped and revegetated the area.

The removal actions have prevented or controlled the release or threatened release of hazardous substances from
the sources of contamination identified in OU2 such that there are no unacceptable risks to human health and the
environment from those sources. Lead is the principal COC. The response actions were designed to control all
COCs in the capped material.

The EPA issued the ROD for OU2 on September 30, 1999. It indicated that the OU2 removal actions reduced or
eliminated any potential risk posed to human health or the environment from releases of hazardous substances
found at the MGTI, the LMGFT and the MTI portions of OU2. Therefore, the OU2 1999 ROD selected a "No

-------
Further Action" remedy assuming the OU remains zoned for Industrial Mining or similar uses that do not allow
residential use. The EPA issued an ESD on July 29, 2013, to clarify that institutional controls are required to
maintain the integrity of and prevent disturbances to engineered features or structures established as part of the
remedy.

Status of Implementation

The EPA partially deleted OU2 from the NPL on July 23, 2001. The Industrial Mining zoning designation for the
MGTI and the MTI remains in place. Future use of the mill and impoundment site will require a permit from the
Colorado Department of Reclamation, Mining and Safety (DRMS), previously the Colorado Division of Mining
and Geology. In addition, Lake County passed an ordinance on April 15, 2013, that acts as an institutional control.
Together, these institutional controls protect remedy components, require best management practices for soil
excavation, and require CDPHE approval for any excavation or earth removal activity that exceeds 10 cubic yards
or that would impact an engineered remedy.

Surface water and groundwater monitoring in the vicinity of OU2 is being addressed as part of OU12.

Systems Operations/Operation & Maintenance (O&M)

In addition to the four removal actions, the 1999 ROD specified the following monitoring requirements to
maintain the effectiveness of the removal actions:

•	Monitor the vegetative covers

•	Inspect impoundments

•	Review the zoning definition to ensure consistency with the remedy

•	Review the status of the Colorado Division of Mining and Geology (now DRMS) permit and use of the
mill and impoundments

•	Upon termination of the Colorado Division of Mining and Geology (now DRMS) permit, ensure that final
facility reclamation is protective of human health and the environment

•	Monitor groundwater for metals and other inorganic parameters in June of each year at nine locations
(conducted as part of the OU12 monitoring program)

CDPHE conducts annual O&M inspections and maintenance activities per the Site's October 2016 O&M Plan.
O&M activities are performed under the EPA grant funded with Special Account monies.5 O&M activities
include inspection and maintenance of the covers and surface water controls. As a result of the September 2021
inspection, TetraTech, the state O&M inspection contractor, made several recommendations to improve the
functionality and longevity of various remedy components. The O&M issues identified do not currently present
concerns for the remedy's protectiveness. CDPHE in consultation with the EPA will determine which of these
recommendations will be implemented as part of O&M activities.

Malta Gulch Tailings Impoundment CDPHE O&M Contractor Recommendations

•	Monitor the erosion features during future inspections

•	Have a comprehensive vegetation inspection performed by a certified specialist

•	Reseed areas lacking vegetation

•	Excavate a larger, more-defined spillway channel to convey potential flows from the pond north of
Tailings Impoundment #3

•	Remove vegetation and transplant trees from channels on eastern and southern edges of Tailings
Impoundment # 1 to facilitate drainage off-site

•	Repair the damaged section on the outlet end of the northeastern culvert and remove the sediment and
vegetation to allow flows to pass through unimpeded and improve drainage from the MGTI

•	Grade the bench on the western edge of Tailings Impoundment #3 to drain down the impoundment face
or reinforce the low spot drainage to minimize erosion

5 Special Accounts arc PRP-funded, site-specific, interest-bearing accounts housed within Superfund s "Hazardous
Substances Superfund (Trust Fund)."

14

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• Repair the fence along the boundary with County Road 36

• Contact the Colorado Department of Reclamation, Mining and Safety and Division of Water Resources to
determine the regulatory status of the MGTI impoundments. If regulated by the Division of Water
Resources, a review of the construction of the embankments with respect to current dam safety rules may
be required.

Malta Tailings Impoundment CDPHE O&M Contractor Recommendations

• Have a comprehensive vegetation inspection performed by a certified specialist

• Have a vegetation specialist develop options to re-establish vegetation in the area where sheet erosion has
removed the topsoil

• Transplant the trees growing in the northern and southern channels

• Continue to inspect the channel for signs of inadequate capacity, such as flow overtopping the channel
banks

• Construct and line a more defined channel on the northern and southeastern boundaries of the site

VI.2 OU2: PROGRESS SINCE PREVIOUS FYR

This section includes the protectiveness determinations and statements from the 2017 FYR Report (Table 5).

There were no recommendations identified from the 2017 FYR Report.

Table 5: Protectiveness Determinations/Statements from the 2017 FYR Report

()l #

PmK'clheiK'ss
Doloi'iniiiiilioii

PniU'Clixeness Si;iicim-nl

Protective

The remedy at OU2 is protective of human health and the environment. The
removal actions conducted at OU2 greatly reduced or eliminated any
potential risk posed to human health or the environment from releases of
hazardous substances and an institutional control ensures that engineered
remedy components are protected and any soil excavation is performed in a
manner protective of human health and the environment.

VI.3 OU2: FYR PROCESS

Data Review

There are no applicable data to review for OU2.

Site Inspection

The OU2 site inspection took place on June 16, 2022. Participants are listed in Section III of this FYR Report.
The capped impoundments remain intact and vegetative covers are in good condition. Fencing and warning signs
are in good condition. It appears that some trespassing occurs, as a few old tires were disposed of at the MGTI.
An inspection checklist has been completed (Appendix F). Representative photographs from the site inspection
are included in Appendix G.

VI.4 OU2: TECHNICAL ASSESSMENT

QUESTION A: Is the remedy functioning as intended by the decision documents?

The site inspection and the review of documents, ARARs and risk assumptions indicate that the remedy is
functioning as intended by the OU's removal actions and the ROD. All institutional controls required by the
decision documents are in place. Should local governments approve a change in land use, procedures are in place
to notify the EPA and CDPHE.

QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of the
remedy selection still valid?

-------
There have been no changes to the ARARs identified in the ROD or since the previous FYR. No newly
promulgated standards have been identified that could call into question the protectiveness of the remedy as
implemented (see Appendix H for more detail). There have been no other changes in exposure assumptions or
toxicity data that would call into question the protectiveness of the remedy. Currently, there are no proposed reuse
plans at the OU2 mill that would affect the protectiveness of the remedy.

QUESTION C : Has any other information come to light that could call into question the protectiveness of the
remedy?

No additional information has come to light that would call into question the protectiveness of the remedy.

VI.5 OU2: ISSUES/RECOMMENDATIONS

Issues/Recommendations

Ol (s) without Issucs/Rccommcndations Identified in the l-'Yk:

OU2

OTHER FINDINGS

Review, assess and implement as appropriate the recommendations in the 2021 O&M OU2, 5 and 7 Inspection
Report.

VI.6 OU2: PROTECTIVENESS STATEMENT

Protectiveness Statement(s)

Operable Unit: Protectiveness Determination:

2 Protective

Protectiveness Statement: The remedy at OU2 is protective of human health and the environment. The
removal actions conducted at OU2 reduced or eliminated any potential risk posed to human health or
the environment from releases of hazardous substances and an institutional control ensures that
engineered remedy components are protected, and any soil excavation is performed in a manner
protective of human health and the environment.

VII. OU3: DENVER & RIO GRANDE WESTERN RAILROAD COMPANY
(D&RGW) SLAG PILES/RAILROAD EASEMENT/RAILROAD YARD

OU3 includes three slag piles - Arkansas Valley (AV) Smelter, La Plata and Harrison Street - owned by the
Denver & Rio Grande Western Railroad Company (D&RGW), an easement that runs diagonally through
Leadville, and part of the rail yard known as Poverty Flats (Figure D-4). Union Pacific (UP) acquired D&RGW's
properties nationwide in 1996, taking over the responsibilities outlined in the 1993 Consent Decree with
D&RGW.

AV Smelter Slag Pile

The AV Smelter Slag Pile covers about 40 acres just west of the Stringtown Mill Area. The pile consists of slag
produced by the AV, which operated from 1882 to 1960. Based on aerial photography, the pile volume in the late
1950s was about 1.2 million cubic yards. In 1998, about 422,000 cubic yards of slag remained, of which 190,000
cubic yards was stockpiled fine slag.

La Plata Slag Pile

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The La Plata Slag Pile, located west of Leadville city limits on Elm Street, has a volume estimated at 105,000
cubic yards. Bimetallic Smelting Company leased the La Plata area in OU3 from 1892 to 1900 for pyritic
smelting of low-grade ores.

Harrison Street Slag Pile

The Harrison Street Slag Pile was located in a residential area, near the northeast corner of Harrison Avenue and
Elm Street, in Leadville. The original slag pile ranged from 20 feet to 50 feet in height, and covered about 3 acres.
The Harrison Street Slag Pile was removed to original grade and relocated to the AV Smelter Slag Pile in March
1998.

Rail Yard

The rail yard, located between 12th Street, Highway 24, 17th Street and County Road 8, has seen over 130 years
of transportation activities mostly associated with mining in the area. The part of the rail yard formerly owned by
D&RGW is near the north end of Leadville, encompasses an area of 43 acres, and is crossed by abandoned rail
lines and access roads. Slag was used in the rail yard as ballast and as a road base to provide support for heavy
vehicle traffic. Slag was also deposited around the loading dock due to spillage during transportation activities.

Rail Easement

The rail easement includes the part of the railroad track that runs diagonally through Leadville. It consists of about
25 feet on either side of the track centerline. Slag was used as a road base to provide support for heavy vehicle
traffic. Slag was also deposited as spillage from passing rail cars.

VII. 1 OU3: RESPONSE ACTION SUMMARY

Basis for Taking Action

Based on the results of the Site's 1989 RI, the 1992 RI and the 1993 screening feasibility study (SFS), the EPA
identified the fine fraction of the stockpiled AV Smelter slag and the potential for particulate release during
ballast operations as a potential human health exposure pathway. Appendix B (Table B-5) provides a chronology
of OU3 events.

Table 6 lists the contaminants found in OU3 media.

Table 6: Contaminated Media, OU3

Modiii

('oill;iilliil;ilioil/lssuo

Slag

Elevated levels of zinc, lead, arsenic and cadmium; low acid-
generating potential and a neutral-to-basic pH.

Fine slag (less than 3/8 of an inch)

Elevated lead.

In May 1996, D&RGW submitted an FS for the stockpiled fine slag at the AV Smelter Slag Pile, in accordance
with the terms of the 1993 Consent Decree.

Response Actions

AV Smelter Slag Pile

After the fine slag (slag with a particle size of 3/8 inch or less) was consolidated at the AV Smelter Slag Pile, the
EPA issued the Stockpiled Fine Slag - AV Smelter Slag Pile ROD (1998 OU3 ROD) on May 6, 1998. Based on
consideration of CERCLA requirements, detailed analyses of alternatives and public comments, the EPA
determined that a "no action" alternative was the appropriate remedy, because no complete human or ecological
exposure pathways were identified for the stockpiled fine slag and the potential for release of metals in leachate
from the stockpiled fine slag is minimal. The 1998 OU3 ROD also included a provision for the potential use of
the slag in the future based on regional market demand for the material as a component in construction materials.

The no action alternative left the stockpiled fine slag in its existing condition with no control or cleanup planned.
The no action alternative included a provision for future use of the slag if it is encapsulated prior to its use or
reuse.

-------
La Plata Slag Pile

Based on the lack of fine slag or leachate generation, the 1998 OU3 ROD did not require remedial action at this
location.

Harrison Street Slag Pile

The 1998 OU3 ROD provides a contingency for resource utilization, which may be undertaken in the future if
regional market demand exists for the material. As part of its ballast operations, UP relocated about 104,000 cubic
yards of slag to the AV Smelter Slag Pile in March 1998 to bring the Harrison Street Slag Pile to grade. As a
result, soils containing elevated concentrations of lead were exposed. These soils create the potential for
unacceptable human health risks if the property was developed for residential use in the future. To date, the land
remains vacant.

Rail Easement

As part of work done under the Site's 1993 Consent Decree, UP submitted a work plan that proposed converting
the easement into a segment of the paved Mineral Belt Bike Trail. The trail was completed in the late 1990s. UP
subsequently donated ownership of the easement to Lake County via a quitclaim deed.

Rail Yard

During summer 1997 and fall 1997, UP removed 1,264 cubic yards of fine slag from the rail yard and placed it
onto the AV Smelter Slag Pile. As a result, soils containing elevated concentrations of lead were exposed. These
soils created the potential for unacceptable human health risks if the property is developed for residential use in
the future.

On August 6, 2014, the EPA issued an ESD that required institutional controls on OU3 properties in the form of a
local ordinance, environmental covenant, and/or restrictive notice.

Status of Implementation

On February 23, 2009, Lake County implemented institutional controls in an ordinance that included OU3. This
ordinance requires best management practices for soil excavation and requires CDPHE approval for any
excavation or earth-removal activity because all of OU3 is considered an engineered remedy. The city of
Leadville adopted a similar ordinance for properties within city limits on May 7, 2013. The EPA completed a
deletion of OU3 from the NPL on April 11, 2016.

Systems Operations/Operation & Maintenance (O&M)

The 1998 no action ROD for OU3 did not require maintenance of the fine slag piles. The 1998 Memorandum of
Understanding (MOU) entered into between UP, Lake County and the EPA indicated that the fine slag on the rail
easement would be incorporated into the Mineral Belt Trail and that Lake County is responsible for long-term
maintenance of the Mineral Belt Trail.

Any future use of the fine slag would require it to be encapsulated for reuse. Encapsulation can include the use of
fine slag in concrete or asphalt aggregate, as a road base or as backfill (so long as the slag is chemically bound or
physically separated from an exposure by a barrier consisting of a different material).

Since the last FYR, several of the properties have changed ownership and future use. CJK Milling acquired the
AV Smelter Slag pile and has received approval from the EPA and CDPHE to use the slag for road base. Lake
County purchased the Harrison Street property from UP and intents to build a Judicial Center on the property; the
EPA provided a "reasonable steps" letter to Lake County. The proposed Rail Yard mixed use development
discussed in the 2017 FYR is under way with several homes constructed; the developer is working with CDPHE
under the voluntary cleanup program and a CDPHE-approved materials management plan.

VII.2 OU3: PROGRESS SINCE PREVIOUS FYR

This section includes the protectiveness determinations and statements from the 2017 FYR (Table 7). There were

-------
no recommendations identified from the 2017 FYR.

Table 7: Protectiveness Determinations/Statements from the 2017 FYR Report

()l #

PmieclheiR'ss
l)cUTinin;ilion

Pro(oc(i\ciK'ss M;iK-iih-iiI

Protective

The remedy at OU3 is protective of human health and the
environment. Institutional controls that protect the engineered
remedy components ensure that soil excavations are performed in a
manner protective of human health and the environment.

VII.3 OU3: FYR PROCESS

Data Review

There are no applicable data to review for OU3.

Site Inspection

The OU3 site inspection took place on June 16, 2022. Participants are listed in Section III of this FYR Report.
The inspection did not result in significant findings. The Rail Easement/Rail Yard area (also known as Poverty
Flats) was annexed into the city of Leadville in January 2017. The new owner contacted CDPHE, as directed in
the institutional controls. A Material Management Plan for the development was approved by CDPHE. During the
inspection, it was noted that several homes have been built and sold and more homes are under construction. In
addition, Lake County purchased the Harrison Street Property from UP in order to construct a new Justice Center.
This property was observed and has not yet been developed. However, the EPA reviewed the development plans
and issued a comfort letter to the county in February 2022, stating that the EPA has not identified any obvious
incompatibility between Lake County's proposed use of the property and the EPA's selected cleanup option, as
described by the county.

All other slag piles in this OU had been relocated to the AV South Hillside Slag Pile in 1998 or incorporated into
the paved Mineral Belt Trail. Photographs were taken of site features, including slag piles (Appendix E). An
inspection checklist has been completed. It is available in Appendix D. The slag piles were intact and appeared to
be in good condition. The Mineral Belt Trail was intact, appeared to be in good condition and was in active use by
people walking, biking and skating. The site inspection checklist and photographs are included in appendices F
and G, respectively.

VII.4 OU3: TECHNICAL ASSESSMENT

QUESTION A: Is the remedy functioning as intended by the decision documents?

The site inspection and the review of documents, ARARs and risk assumptions indicate that the remedy is
functioning as intended by the no action ROD for OU3.

All institutional controls required by site decision documents are in place. The EPA and CDPHE will be notified
if local governments approve a change in land use.

QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of the
remedy selection still valid?

There have been no changes to the ARARs identified in the ROD or since the previous FYR. No newly
promulgated standards have been identified that could call into question the protectiveness of the remedy as
implemented (see Appendix H for detail). There have been no other changes in exposure assumptions or toxicity
data that would call into question the protectiveness of the remedy. There are currently no proposed reuse plans
for OU3 that would affect the protectiveness of the remedy.

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QUESTION C : Has any other information come to light that could call into question the protectiveness of the
remedy?

The OU3 ROD focused on fine slag at the AV Smelter Slag Pile. Redevelopment proposals for the Harrison Street
and Rail Yard (Poverty Flats) properties highlighted that fine slag may not be the only contaminated media of
concern at OU3. As a result, an ESD signed on August 6, 2014, required institutional controls. In addition, the
EPA clarified the use of the term "contingency" for fine slag utilization in the 1998 ROD. Fine slag can be used
for future commercial purposes by following the requirements set out in the 1998 ROD. The city of Leadville
adopted an ordinance on May 7, 2013, and Lake County on February 23, 2009, that limits unacceptable exposures
to slag and contaminated soils. The EPA partially deleted OU3 from the NPL in 2016.

The contingency has been exercised by the Leadville Scenic Railroad and the CJK Milling Company, which
requested letters for approval to use this contingency provision in early January 2022. In mid-January 2022, the
EPA and CDPHE approved the use or reuse of the slag material as a commercial product as long as the slag is
encapsulated for reuse.

Lake County purchased the Harrison Street Property from UP in order to construct a new Justice Center. The
county reached out to the EPA to obtain a "Reasonable Steps" letter regarding the development plans. The EPA
reviewed the development plans and issued a comfort letter to the county in February 2022, stating that the EPA
has not identified any obvious incompatibility between Lake County's proposed use of the property, as described
by the county, and the EPA's selected cleanup option.

Development in the former Harrison Street slag pile does not call into question the protectiveness of the OU3
remedy due to the reasons listed below.

• In 1998, UP removed the Harrison Street Slag Pile, returning the area to its original grade, and relocated
the pile to the AV Slag Pile.

• After the removal, confirmation data show lead in the soils on the Harrison Avenue property may create
the potential for unacceptable human health risks if the property is developed for residential use (> 3,500
mg/kg).

• Lake County (in 2009) and the city of Leadville (in 2013) implemented ordinances requiring CDPHE
approval for any excavation or earth removal activity.

VII.5 OU3: ISSUES/RECOMMENDATIONS

Issues/Recommendations

()l (s) without Issucs/Rccommcndations Identified in the l-'Yk:

OU3

VII.6 OU3: PROTECTIVENESS STATEMENT

Protectiveness Statement(s)

Operable Unit: Protectiveness Determination:

3 Protective

Protectiveness Statement: The remedy at OU3 is protective of human health and the environment.
Institutional controls that protect the engineered remedy components ensure that soil excavations are
performed in a manner protective of human health and the environment.

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VIII. OU4: UPPER CALIFORNIA GULCH

Upper California Gulch (OU4) is part of the Leadville Historic Mining District. It is located southeast of
Leadville (Figure D-5). Placer gold mining started with the discovery of gold in California Gulch in 1860. When
the placer deposits were exhausted, underground mining was used to extract gold, silver, lead and zinc ore. Breece
Hill, above Upper California Gulch, was networked with underground mines in an area that covers about eight
square miles. As mines were developed, waste rock was excavated and left near the mine entrances. Although a
total of 131 waste piles were initially identified in OU4, the number of waste rock piles of concern in the OU has
been reduced to 20 through investigations and analytical screening.

The OU4 waste piles are divided into six sub-basins: Garibaldi, Whites Gulch, Nugget Gulch, AY Minnie, Iron
Hill and South Area, which also includes the Fluvial Tailing Site 4 (FTS 4), also known as Oro City. The 20
waste rock piles in these sub-basins contain a total estimated volume of 431,000 cubic yards, impacting 28.3
acres. Fluvial tailings deposition is discontinuous and appears to have been subdivided into several distinct
pockets. In OU4, the FTS 4 extends for a distance of approximately 1.5 miles along Upper California Gulch, from
slightly upstream of the Yak Tunnel portal to the upstream end of the Printer Boy Mine area. The waste rock piles
are primarily weathered porphyry with limited to no vegetation, and with highly oxidized surfaces. Fluvial tailings
and fluvial tailings mixed with alluvial sediments are located in the South Area and FTS 4/Oro City and have an
estimated volume of 102,000 cubic yards. The tailings piles are largely unvegetated, with grasses and lodgepole
pine growing on a quarter of the tailings surface. A wetland area exists along the Upper California Gulch channel,
within OU4 boundaries. Oro City is considered a cultural and historic resource in the Leadville Historic Mining
District.

The land in OU4 is zoned for industrial and mining land uses.

VIII. 1 OU4: RESPONSE ACTION SUMMARY

Basis for Taking Action

Based on the results of the OU4 1994 RI/FS, the EPA determined that actual or threatened releases of hazardous
substances at and from waste rock and fluvial tailings piles on OU4 may present an imminent and substantial
endangerment to public health, welfare or the environment if not addressed through remedial action. Metals from
former mining activities are present in waste rock and fluvial tailings piles and may leach to surface water or
groundwater via ARD. Appendix B (Table B-6) provides a chronology of OU4 events.

Response Actions

Resurrection Mining Company completed removal activities from 1995 to 1996, prior to the issuance of the 1998
ROD. The activities included work on the Garibaldi Mine in the Garibaldi sub-basin, work on the Agwalt Mine in
Whites Gulch, and work on the Upper California Gulch surface water diversion. The ROD identified the need for
more response activities in the Garibaldi sub-basin, Whites Gulch (Printer Girl Waste Pile), Nugget Gulch Waste
Rock, AY Minnie Waste Rock, Iron Hill Waste Rock and FTS 4/Oro City.

The EPA issued the ROD for OU4 on March 31, 1998. The RAOs established in the 1998 OU4 ROD include:

• Control erosion of contaminated materials into local water courses

• Control leaching and migration of metals from contaminated materials into the surface water

• Control leaching and migration of metals from contaminated materials into the groundwater

The selected remedy for OU4 consisted of the following remedial components:

• Garibaldi sub-basin:

o Diversion of surface water and selected removal of waste

• Whites Gulch sub-basin:

o Excavation, consolidation and removal of waste rock at the Printer Girl Waste Rock Pile.

-------
o Regrading of excavated areas of the Printer Girl Waste Rock Pile and construction of diversion
ditches to control surface water run-on to the regraded areas

• Nugget Gulch sub-basin:

o Excavation and consolidation of the Rubie, Adirondack, Colorado No. 2 East, and North Mike

Waste Rock Piles onto the Colorado No. 2 Waste Rock Pile
o Regrading and placement of a simple rock or vegetated cover over the Colorado No. 2 Waste
Rock Pile

o Terracing, soil amendment and revegetation of excavated areas

o Construction of diversion ditches to control surface water run-on to the terraced and regraded
areas

• AY Minnie sub-basin:

o Construction of diversion ditches to reduce surface water run-on onto the AY Minnie Waste Rock
Pile

o Relocation of Lake County Road 2 to allow space for construction of a sedimentation pond and
provide added protection from stability failures of timber cribbing without destroying the mining
heritage and cultural resources of this mining area

• Iron Hill sub-basin:

o Regrading and placement of a simple cover (revegetated soil or rock) over the Mab Waste Rock
Pile as well as revegetation of surrounding disturbed areas

• Oro City:

o Reconstruction and stabilization of the Upper California Gulch stream channel to prepare for a
500-year flood event

o Regrading and removal, if necessary, of channel spoil material and selected fluvial tailings
o Construction of eight sediment dams in the channel and about 1.5 acres of wetlands along the
channel

The OU4 ROD did not contain numeric cleanup standards, but was meant to address potential source material
contributing to surface water and groundwater contamination at the Site. On March 17, 2004, the EPA issued an
ESD deferring remedial activities at FTS 4/Oro City in response to concerns regarding the historical significance
of the Oro City area as an early mining camp. This decision was supported by interim surface water and
groundwater monitoring data. The OU12 remedy addresses sitewide surface water and groundwater
contamination to monitor the effectiveness of the source control remedies. Further source remediation may be
conducted under OU12 if deemed necessary. On July 29, 2013, the EPA issued an ESD to add institutional
controls as a component of the OU4 remedy.

Status of Implementation

The removal action at the Garibaldi sub-basin finished in January 1996. Response actions at Nugget Gulch,

Whites Gulch, AY Minnie and Iron Hill began in 1998. Resurrection completed the remedial actions in
accordance with the 1998 ROD in 2001.

In December 2010, Lake County implemented institutional controls for OU4 in the form of a resolution amending
the Lake County Land Development Code and adopting regulations that protect both engineered and non-
engineered remedies at OU4 (see K. 1 in Appendix K). A best management practice handout is provided to all
applicants applying for a building permit within OU4. In addition, any disruption of engineered or non-engineered
remedies within OU4 requires written approval from CDPHE. In addition to the institutional controls provided by
the 2008 Consent Decree and the Lake County regulations, all OU4 is in Lake County's Industrial Mining zoning
district, which serves to limit future changes of land use without county approval and notification to the EPA and
CDPHE of such proposed changes. In addition, Newmont/Resurrection recorded environmental covenants on its
OU4 properties on July 31, 2012, and October 1, 2012. These covenants prohibit residential use and restrict
groundwater use. The EPA deleted OU4 from the NPL on October 24, 2014.

Systems Operations/Operation & Maintenance (O&M)

Newmont/Resurrection conducts inspections in accordance with the OU4, 8, 10, Operations and Maintenance

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Plan, California Gulch Superfund Site, which is Appendix D to the 2008 Consent Decree approved on August 29,
2008. Its findings are documented in the Annual California Gulch Superfund Site OU4, OU8 and OU10
inspection reports. During this FYR period, Newmont/Resurrection completed routine maintenance and repairs to
ditches such as removing debris, vegetation, and reseeding localized barren areas.

VIII.2 OU4: PROGRESS SINCE PREVIOUS FYR

This section includes the protectiveness determinations and statements from the 2017 FYR Report (Table 8).
There were no recommendations identified from the 2017 FYR Report.

Table 8: Protectiveness Determinations/Statements from the 2017 FYR Report

()l #

I'mU'iiiteni'ss
Dclcrmiiiiilion

l>ro(cc(i\oiK'ss Siiiiomcnl

Protective

The remedy at OU4 is protective of human health and the environment.
Exposure pathways that could result in unacceptable risks are being
controlled by diverting contaminated surface water and removing,
consolidating and/or covering mine waste. Institutional controls have
been implemented to ensure that engineered remedy components are
protective and that any soil excavation is performed in a manner
protective of human health and the environment. Residentiaf use is
prohibited in certain portions of OU4.

VIII.3 OU4: FYR PROCESS

Data Review

There are no applicable data to review for OU4.

Site Inspection

The OU4 site inspection took place on June 16, 2022. Participants are listed in Section III of this FYR Report.
Photographs were taken of representative waste piles (Appendix G). An inspection checklist has been completed.
It is available in Appendix F.

An unpaved roadway crosses OU4. Based on the results of the O&M activities conducted during this FYR,
Newmont/Resurrection completed routine maintenance and repairs to ditches such as removing debris and
vegetation and reseeding localized barren areas. Most of the OU4 waste piles have been removed and
consolidated; some piles have been revegetated or covered with rock and posted with no trespassing signs. There
are roadways throughout OU4 that local residents and tourists use to access various parts of the Site, primarily for
recreation activities.

VIII.4 OU4: TECHNICAL ASSESSMENT

QUESTION A: Is the remedy functioning as intended by the decision documents?

Newmont/Resurrection constructed surface water diversion structures, moved mining waste; excavated and
consolidated mining wastes and covered and regraded the covered waste rock. Under the 2008 Consent Decree,
Newmont/Resurrection agreed to operate and maintain OU4 remedy features. All institutional controls required
by site decision documents are in place as are procedures to notify the EPA and CDPHE should local
governments approve a change in land use. In addition, Newmont/Resurrection placed environmental covenants
on its OU4 properties to further protect remedy features. These environmental covenants were recorded with the
Lake County Clerk and Recorder's Office on July 31, 2012, and October 1, 2012.

QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of the
remedy selection still valid?

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There have been no changes to the ARARs identified in the ROD or since the previous FYR. No newly
promulgated standards have been identified that could call into question the protectiveness of the remedy as
implemented (see Appendix H for details). The 1998 OU4 ROD did not establish numeric cleanup standards for
surface water or groundwater. The RAOs identified in the 1998 OU4 ROD included controlling erosion of
contaminated materials into local waterways and controlling the leaching and migration of contaminated materials
into surface water and groundwater. These RAOs have largely been achieved based on the review of the sitewide
data collected as part of OU12.

QUESTION C : Has any other information come to light that could call into question the protectiveness of the
remedy?

No additional information has come to light that would call into question the protectiveness of the remedy.

VIII.5 OU4: ISSUES/RECOMMENDATIONS

Issues/Recommendations

()l (s) without Issucs/Rccommcndations Identified in the l-'Yk:

OU4

VIII.6 OU4: PROTECTIVENESS STATEMENT

Protectiveness Statement(s)

Operable Unit: Protectiveness Determination: Planed Addendum

4 Protective Completion Date:

Click here to enter a date

Protectiveness Statement: The remedy at OU4 is protective of human health and the environment.
Exposure pathways that could result in unacceptable risks are being controlled by diverting
contaminated surface water and removing, consolidating and/or covering mine waste. Institutional
controls have been implemented to ensure that engineered remedy components are protective, and that
any soil excavation is performed in a manner protective of human health and the environment.
Residential use is prohibited in certain portions of OU4.

IX. OU5: ASARCO SMELTERS/SLAG/MILL SITES

OU5 includes five smelter sites - the Elgin Smelter, the Grant/Union Smelter, the Western Zinc Smelter, the
AV South Hillside Slag Pile (collectively known as the EGWA sites), and the AV Smelter. OU5 also includes one
mill site, the Colorado Zinc-Lead Mill (CZL) which is co-located with the AV Smelter (Figure D-6).

The AV/CZL site is located about 1.5 miles southwest of Leadville on the north bank of California Gulch. The
combined area covers about 70 acres. The entire AV/CZL site lies above the 500-year floodplain of Lower
California Gulch. This site is also next to parts of OU3 that includes the AV Smelter Slag Pile. The AV Smelter,
which is part of the Leadville Historic Mining District, operated from 1879 to 1961. It was the longest-operating
smelter in the Leadville area, processing a wide variety of ores and reprocessing slag to produce lead, silver and
other metals. The CZL operated intermittently from 1926 to 1938, using a custom flotation process to produce
zinc, lead, gold, silver and some copper. The byproduct of mill operations was tailings that were discharged below
the mill, presumably into the CZL Tailing Impoundment (OU8). The mill closed in 1930. After remodeling, it
reopened in 1935 to process ores from several local mines and waste dumps; these operations ceased in 1938.

The Elgin Smelter, which operated intermittently from 1879 to 1903, is located in north-central Leadville, on the

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south bank of Big Evans Gulch, near the intersection of U.S. Highway 24 and State Highway 91. Several different
companies leased and operated the Elgin Smelter works between 1893 and 1902. The Grant/Union Smelter was
actually two smelters - the Grant Smelter, which operated from 1878 to 1882, and the Union Smelter, which
operated from 1892 to 1900. Both smelters were near the confluence of Georgia Gulch and California Gulch,
northeast of the Colorado Mountain College campus. The Western Zinc Smelter, which operated from 1914 to
1926, is located in the western part of Leadville, about 75 feet west of McWethy Drive and about 100 feet south
of the Lake County fairgrounds. The Western Zinc Mining and Reducing Company used the facility to extract
zinc from ores.

The AV South Hillside Slag Pile (also referred to as the Tramway Slag Pile) is located south of U.S. Highway 24
on the hillside across from the AV Smelter site. It was perhaps used by the AV Smelter or the Grant/Union
Smelter. The site consists of an estimated 16,000 cubic yards of slag in two elongated piles that extend about
2,000 feet parallel to California Gulch and U.S. Highway 24. There are no smelter remains or any other waste
materials except slag at this site.

Prior to the remedial action, smelter debris covered much of the OU5 area. The debris consisted primarily of
brick, concrete, metal, tile, wood and glass, as well as residual mine waste and smelter materials, including
coke/charcoal, limestone, ore, matte, tailings and flue dust.

Most of the smelter and mill structures at the AV/CZL site have been demolished, though some buildings and
foundations remain preserved as cultural heritage properties. The EGWA sites are currently vacant.

IX.l OU5: RESPONSE ACTION SUMMARY

Basis for Taking Action

The final sitewide BRAs conducted from 1991 to 1996 identified non-residential soils and future residential area
soils as potential media of concern at OU5. Metals from former mining practices, including lead, arsenic,
cadmium, copper and zinc in soil and air, presented a potential risk to human and ecological receptors. The human
health risks at the Site have been attributed to lead and arsenic. Therefore, these two contaminants were selected
as indicator chemicals for remedial response. Appendix B (Table B-7) provides a chronology of OU5 events.

Table 9 lists the contaminated medium at OU5.

Table 9: Contaminated Medium, OU5

Medium

AiViiolOl 5

('oni;imin;iiion

Soil

Results of the soils investigation indicate elevated
arsenic, cadmium, lead and zinc levels; the highest
levels of contamination were detected in samples
from the baghouse area.

CZL

Elevated lead levels

Elgin Smelter

Elevated lead and arsenic levels

Grant/Union Smelter

Elevated lead and arsenic levels

Western Zinc Smelter

Elevated lead and arsenic levels

AV South Hillside Slag Pile

Elevated lead and arsenic levels

Response Actions

In September 1990, the EPA and ASARCO Incorporated signed an AOC for sampling at the Site. In 1991, the
EPA issued a UAO that required ASARCO Incorporated to conduct studies and complete RIs. In August 1994,
ASARCO Incorporated entered into a Consent Decree with the United States, the State and PRPs to perform
certain remediation work in OUs 5, 7 and 9.

The EPA issued two RODs for OU5. The EPA issued the OU5 ROD for the AV/CZL site on September 29, 2000.
The EPA issued the second OU5 ROD for the EGWA sites on October 31, 2000.

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The 0U5 ROD for the AV/CZL established the following RAOs:

Tailings

•	Control airborne transport of tailings particles

•	Control erosion of tailings into local water courses

•	Control leaching and migration of metals from tailings into surface water

•	Control leaching and migration of metals from tailings into groundwater

Flue Dust

•	Control airborne transport of flue dust particles

•	Control erosion of flue dust and deposition into local water courses

•	Control release and migration of metals from flue dust in surface water

•	Control leaching and migration of metals from flue dust into groundwater

•	Control contamination exposure to humans, animals and aquatic life

Non-residential Area Soils

•	Control airborne transport of contaminated materials

•	Control erosion of contaminated materials and deposition into local water courses

•	Control leaching and migration of metals from soils in surface water

•	Control leaching and migration of metals from soils into groundwater

•	Control contamination exposure to humans, animals and aquatic life

Residential Area Soils

• Prevent direct exposure of the population to elevated concentrations of contaminants in the surface soil.
The remedy selected for the AV/CZL site consisted of:

•	Excavation of flue dust and relocation to a single-lined, fully encapsulated repository.

•	Consolidation of tailings and non-residential soils and placement of an 18-inch vegetated soil cover over
the consolidated pile. This remedy will make portions of the AV/CZL site a permanent waste
management area.

•	Implementation of institutional controls such as deed notices or deed restrictions to provide notification
that a barrier is in place and to restrict land uses incompatible with the remedy.

•	Development of an O&M program during the remedial design to include inspection and maintenance of
the cover and surface water controls, as well as inspection for evidence of erosion, differential settlement
of the cover and adequacy of vegetation.

The OU5 ROD for the EWGA established the following RAOs:

Slag

•	Control of leaching of metals of concern in concentrations that would have an adverse impact on soils,
surface water, or groundwater

•	Control airborne transport of contaminated materials

•	Control erosion of contaminated materials to prevent deposition into local surface water courses

Non-residential Area Soils

•	Control airborne transport of contaminated materials

•	Control erosion of contaminated materials and deposition into local water courses

•	Control leaching and migration of metals from soils in surface water

•	Control leaching and migration of metals from soils into groundwater

•	Control contamination exposure to humans, animals and aquatic life

26

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Residential Area Soils

• Prevent direct exposure of the population to elevated concentrations of contaminants in the surface soil.
The remedy selected for the EGWA sites consisted of:

• Implementation of institutional controls to warn of potential hazards and to maintain the effectiveness of
the remedy by limiting access to or use of the property for current or potential future land use scenarios

The 2000 EGWA ROD determined that the selected remedy would control airborne transport, erosion and metals
leaching from contaminated materials because no significant pathway for transport of constituents from slag or
soil to other environmental media have been identified for the EGWA sites.

The 2000 OU5 RODs for the EGWA sites and AV/CZL site did not contain numeric cleanup standards but were
meant to address potential source material contributing to surface water, groundwater and releases to air. The
OU12 remedy addresses sitewide surface water and groundwater contamination to measure effectiveness of
source control remedies. The EPA issued a minor ROD Modification (ROD Mod) on May 16, 2013, that clarifies
the institutional controls.

Status of Implementation

Implementation of the 2000 OU5 AV/CZL ROD began in June 2002. Some smelter structures were demolished,
flue dust was excavated, and contaminated materials were transported to an on-site repository. Tailings and
contaminated soil were consolidated on site and placed under 18 inches of clean soil cover that was then
vegetated. Diversion ditches to prevent run-on and ponding on the consolidated waste pile were also constructed.
Remedial actions were initiated by ASARCO Incorporated but discontinued when the company filed for
bankruptcy. The EPA assumed lead responsibility for implementation of the OU5 remedy through a settlement
agreement between ASARCO Incorporated and the federal government signed in 2007. The EPA completed OU5
remedial activities in 2010 and an O&M plan in 2016.

The OU5 RODs for both the EGWA sites and the AV/CZL sites included institutional controls as a component of
the remedy. After the original overlay district concept for implementation of institutional controls proved
infeasible, an alternate course of action was designed during the previous FYR period. Lake County passed an
ordinance that acts as an institutional control on April 15, 2013. It protects remedy components, requires best
management practices for soil excavation, and requires CDPHE approval for any excavation or earth removal
activity that exceeds 10 cubic yards. The city of Leadville adopted a similar ordinance for properties in OU5 and
within city limits on May 7, 2013. The EPA partially deleted OU5 from the NPL on October 24, 2014.

Systems Operations/Operation & Maintenance (O&M)

CDPHE conducts annual O&M inspections and maintenance activities, per the Site's October 2016 O&M Plan.
O&M activities are performed under the EPA grant funded with Special Account monies. O&M activities include
inspection and maintenance of the covers and surface water controls. As a result of the September 2021
inspection, TetraTech, the State O&M Inspection contractor, made several recommendations to improve the
functionality and longevity of various remedy components. The O&M issues identified do not currently present
concerns for the remedy's protectiveness. CDPHE in consultation with EPA will determine which of these
recommendations will be implemented as part of O&M activities.

Arkansas Valley Smelter CDPHE O&M Contractor Recommendations

• Have a comprehensive vegetation inspection performed by a certified specialist

• Reshape the riprap-lined channel adjacent to the ruins on the northern side of the AV repository

• Remove the excess riprap and repair the downstream end of the eastern culvert to restore the culvert's
capacity

• Install a locking device on the Sump to minimize tampering

• With the potential for unauthorized access to the site, it is recommended that "No Trespassing" signs be
placed around each of the historic concrete structures to discourage access.

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• Repair the well casing AVRPMW-3

Colorado Zinc-Lead Mill CDPHE O&M Contractor Recommendations

• Have a comprehensive vegetation inspection performed by a certified specialist

• Institute erosion control measures on unvegetated slopes to minimize the potential for continued erosion
and transport of soils off site

• Institute run-on controls to minimize the impact of future erosion

• Construct runoff control berms along the toe of the eroding slopes to minimize the potential for metal-
laden soils to enter California Gulch

Grant/Union Smelter CDPHE O&M Contractor Recommendations

• After slag removal, utilize slope shaping to stabilize slopes and cover up erodible soils

Western Zinc Smelter Recommendations

• Reshape and reinforce channels in each of the locations noted. The purpose is to provide adequate
capacity and material for an estimated flow rate to prevent further gully erosion or channel migration.

Arkansas Valley South Hillside Slag Pile CDPHE O&M Contractor Recommendations

• "No Trespassing" signs are recommended to discourage vehicle access onto the slag piles.

IX.2 OU5: PROGRESS SINCE PREVIOUS FYR

This section includes the protectiveness determinations and statements from the 2017 FYR Report (Table 10).
There were no recommendations identified from the 2017 FYR Report.

Table 10: Protectiveness Determinations/Statements from the 2017 FYR Report

()l #

PmU'iiiteiiess
lk'Urniin;i(ion

Pmlecliu'iiess M;iU-im-nl

Protective

The remedy at OU5 is protective of human health and the
environment. Source contamination has been addressed
through engineered remedy components. Institutional controls
restrict land uses that would be incompatible with this remedy.
The RAOs stated in the two 2000 OU5 RODs for the EGWA
Sites and the AV/CZL Sites have been achieved. In addition,
CDPHE ensures the remedy remains functioning as intended
through routine O&M activities. All institutional controls
required by site decision documents are in place, as are
procedures to notify the EPA and CDPHE should local
governments approve a change in land use.

IX.3 OU5: FYR PROCESS

Data Review

There are no applicable data to review for OU5.

Site Inspection

The OU5 site inspection took place on June 16, 2022. Participants are listed in Section III of this FYR
Report. The site inspection checklist and photographs are included in appendices F and G, respectively. All
contaminated materials at OU5 former smelter areas have been consolidated and put under a protective cover. The
covers are vegetated and in good condition.

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IX.4 OU5: TECHNICAL ASSESSMENT

QUESTION A: Is the remedy functioning as intended by the decision documents?

The site inspection and the review of documents, ARARs and risk assumptions indicate that the Site's OU5
remedy is functioning as intended by site decision documents. An 18-inch soil cover was placed over the
consolidated waste. The grading of the cover's surface promotes positive drainage. Vegetation minimizes erosion
and the potential for exposure to contaminants. In addition, surface water diversion channels minimize run-on and
ponding on the surface of the waste management unit. The EPA assumed the lead for remedial and O&M
activities at OU5 through a settlement with ASARCO Incorporated in 2007. CPDHE is currently responsible for
O&M activities.

The EPA completed construction of the engineered remedy in 2010. All institutional controls required by site
decision documents are in place. The EPA and CDPHE will be notified should local governments approve a
change in land use. In addition, the EPA signed a minor ROD modification on May 16, 2013, that clarified the
institutional controls. The EPA partially deleted OU5 from the NPL on October 24, 2014.

QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of the
remedy selection still valid?

The RAOs identified in the selected remedies for OU5 included controlling erosion of contaminated
materials into local waterways; controlling the leaching and migration of contaminated materials into surface
water and groundwater; controlling airborne transport of contaminated materials; controlling contamination
exposure to humans, animals and aquatic life; and preventing direct exposure of humans to elevated contaminant
levels in surficial soil. These RAOs have been achieved through implementation of the engineered remedy.

There have been no changes to the ARARs identified in the OU5 RODs or since the previous FYR. No newly
promulgated standards have been identified that could call into question the protectiveness of the remedy as
implemented.

QUESTION C : Has any other information come to light that could call into question the protectiveness of the
remedy?

As per Lake County Resolution 2013-12, written approval from CDPHE is required to excavate and remove any
earthen materials, including, but not limited to, native dirt, mine waste rock (e.g., tailings, slag, flue dust) in
excess of 10 cubic yards from a non-engineered remedial component of the Site. In July 2019, the Leadville,
Colorado & Southern Railroad Company contacted CDPHE to move slag material from the Grant/Union Smelter
Site (OU5) to Southern Railroad's property (OU3) for use as railroad ballast. CDPHE reviewed and approved the
proposal in September 2019. No other information has come to light that could call into question the
protectiveness of the remedy.

IX.5 OU5: ISSUES/RECOMMENDATIONS

Issues/Recommendations

()l (s) without Issiies/Reconinieiulntions Identified in (ho I YR:

OU5

OTHER FINDINGS

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Review, assess and implement as appropriate the recommendations in the 2021 O&M OU2, 5 and 7 Inspection
Report.

IX.6 OU5: PROTECTIVENESS STATEMENT

Protectiveness Statement(s)

Operable Unit: Protectiveness Determination:

5 Protective

Protectiveness Statement: The remedy at OU5 is protective of human health and the environment.
Source contamination has been addressed through engineered remedy components. Institutional
controls restrict land uses that would be incompatible with this remedy. The RAOs in the two 2000
OU5 RODs for the EGWA sites and the AV/CZL sites have been achieved. In addition, CDPHE
ensures the remedy continues to function as intended through routine O&M activities. All institutional
controls required by site decision documents are in place, as are procedures to notify the EPA and
CDPHE should local governments approve a change in land use.

X. OU6: STRAY HORSE GULCH AND EVANS GULCH WATERSHEDS

Located east of Leadville, OU6 is 3.4 square miles in size (Figure D-7). OU6 consists of several consolidated
mine waste piles (including Hamm's Tailing Impoundment and the Penrose Mine Waste Pile), and about 2,200
acres of mining wastes in Stray Horse Gulch, the upper portion and headwater of Evans Gulch, and the lower
portion of Evans Creek. On its western boundary, OU6 also includes some residential areas in Leadville and a
drainage corridor along 5 th Street and Starr Ditch downstream of the confluence with the Stray Horse drainage.
Appendix D contains maps identifying the location of individual tailings piles by number and areas addressed by
the pre-ROD removal action phases, as well as a detailed view of the Stray Horse Gulch area of OU6.

The headwaters of Stray Horse Gulch are east of Leadville, in the area of Breece Hill and the Ibex/Irene
Milling/Mining Complex. This water flows through Leadville via the 5th Street drain and Starr Ditch and
eventually discharges to Lower California Gulch. The Hamm's Tailing Impoundment covers an area of about 6.5
acres, with a volume of about 245,000 cubic yards. The impoundment is located in Stray Horse Gulch. The
Penrose Mine Waste Pile was located south of East 4th Street in Leadville and east of Hazel Street. The Penrose
Mine Waste Pile covered an area of about 4 acres. It contained about 173,000 cubic yards of waste rock.

Historically, during heavy periods of precipitation or snow melt, tailings materials from both Hamm's Tailing
Impoundment and Penrose Mine Waste Pile have been eroded and suspended in surface waters moving
downslope through residential areas of Leadville. This surface water is collected by Starr Ditch and conveyed by
the ditch to California Gulch and the Arkansas River. In addition, metals leached from the multiple other mine
wastes present in OU6 and were transported to California Gulch via the portion of Starr Ditch south of 5th Street.

Lake County's current zoning designation for most of OU6 is industrial mining. Other current land uses for
smaller areas of OU6 include recreation, commercial activities, mine tourism and residential uses. The Leadville
area has been classified as a National Historic Landmark. Little Stray Horse Gulch contains several famous
historic mines, including the Matchless Mine of Baby Doe and Horace Tabor.

X.l OU6: RESPONSE ACTION SUMMARY

Basis for Taking Action

The final sitewide BRA evaluated soil, slag, waste rock and tailings in upland areas, as well as fluvial tailings and
sediments in riparian areas. Contaminants evaluated included arsenic, antimony, barium, beryllium, cadmium,
chromium, copper, lead, nickel, manganese, mercury, silver, thallium and zinc. The EPA selected lead and arsenic
as indicator chemicals for cleanup based on the human health risk posed by these two contaminants at the Site.

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Table 11 lists contaminated media in OU6. Appendix B (Table B-8) provides a chronology of OU6 events.

Table 11: Contaminated Media, OU6

Mcriiii

Conliiiniiiiilioii

Sediment

Based on data from the 1997 EE/CA for Stray Horse Gulch, elevated metals contamination was
found in the sampling stations along Stray Horse Gulch.

Mine tailings
and waste
rock piles

The Stray Horse Gulch tailings and waste rock piles were analyzed by x-ray fluorescence for
lead and arsenic concentrations as part of the mine waste piles RI. Surface soils contained
elevated arsenic, lead, cadmium and zinc levels. Subsurface and foundation soils contained
significantly elevated levels of arsenic, cadmium, lead and zinc.

Response Actions

The EPA implemented several response actions at OU6 between 1990 and 2001 (see Table B-9 for a
comprehensive list), prior to the signing of the ROD to systematically clean up most mine wastes causing
contamination in OU6. These response actions included:

•	Relocation, consolidation and/or capping of selected mine waste piles

•	Collection and treatment of ARD from mine waste piles. Treatment occurs at the WTP operated by the
U.S. Bureau of Reclamation (USBR) at the portal of the Leadville Mine Drainage Tunnel (LMDT).

•	Construction of ARD retention ponds and subsequent maintenance

•	Diversion of clean surface water around mine wastes

•	Rehabilitation of Stray Horse Gulch and Starr Ditch

The EPA issued the ROD for OU6 on September 25, 2003. The 2003 OU6 ROD identified the following RAOs
for OU6:

•	Control erosion of mine waste rock and deposition into local water courses

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

•	Control leaching of metals from mine waste rock into groundwater

•	Prevent direct unacceptable exposures to elevated concentrations of contaminants in the soil and waste
rock

The OU6 selected remedy consisted of the following elements:

•	Maintenance of the existing response actions implemented prior to the ROD

•	Installation of bulkheads in the LMDT

•	Pumping ARD impounded behind the bulkhead to the surface with conveyance to the USBR treatment
plant via a gravity pipeline

•	Removal of the Ponsardine mine waste pile, with on-site disposal

•	Repair of unstable cribbing associated with the Robert Emmet mine site

•	Institutional controls to address future changes in land use

The EPA modified the 2003 OU6 ROD with an AROD on September 28, 2010, to expand 2003 ROD remedy to
include diversion systems and address additional waste rock piles as follows:

•	Phase 1: Improve the clean water diversion systems along the Mahala, Pyrenees, Greenback, RAM, Old
and New Mikado and Adelaide-Ward waste rock piles

•	Phase 2: Selectively cap additional mine waste rock piles to decrease the volume of ARD generated

•	Phase 3: Enlarge and enhance the current ARD collection system and retention ponds

•	Eliminate the use of the LMDT and USBR LMDT Treatment Plant from the OU6 remedy, except in the
case of emergencies

•	Shift the monitoring of groundwater and water levels in the LMDT to OU12 Sitewide Water Quality

•	Site and construct a sitewide repository in OU6

31

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•	Remove implementation of bulkheads in the LMDT

•	Implement institutional controls to protect engineered remedies and to reduce exposure to contaminants
that will remain

The 2003 OU6 ROD and 2010 OU6 AROD did not contain numeric cleanup standards, but were meant to address
potential source material contributing to surface water and groundwater contamination. The OU12 remedy
addresses sitewide surface water and groundwater contamination to monitor the effectiveness of the source
control remedies.

Status of Implementation

Since 2012, the following remedy elements of the 2003 OU6 ROD and 2010 OU6 AROD have been
implemented:

•	Maintenance of the existing response actions implemented prior to the ROD

•	Removal of the Ponsardine mine waste pile, with on-site disposal

•	Repair of unstable cribbing associated with the Robert Emmet mine site

•	Multiple tracer and other studies to investigate the existence and quality of a hydraulic connection
between the Marion adit and the LMDT. These studies assessed the effectiveness of the 2000 removal
action that diverted ARD discharged by surface water control structures to the subsurface for conveyance
to the USBR WTP.

•	Remedial design activities

•	Installation of monitoring wells in the LMDT as part of data collection to support remedial design
activities

•	A non-time-critical removal action in 2005 to construct an engineered outlet for the Gaw Shaft. The Gaw
Shaft is believed to be a relief point for the mine pool impounded behind suspected blockages in the
LMDT

•	Installation of a relief well during the 2008 State of Emergency due to high water levels and a blockage in
the LMDT

•	Pumping the water in the Mikado Pond to the Marion Pond in 2011 to prevent an uncontrolled release
into Stray Horse Gulch

•	Removal of sediment in the Marion, Greenback, Mikado and Adelaide ponds, and addition of signage and
fencing in 2012

•	Adoption of an ordinance enacting institutional controls in OU6 along Starr Ditch by the city of Leadville
on May 7, 2013. These institutional controls protect remedy components, require best management
practices for soil excavation, and require CDPHE approval for any excavation or earth removal activity that
exceeds 10 cubic yards. Additional areas of OU6 are zoned for industrial mining and business use. The
need for additional institutional controls on portions of OU6 outside city limits is being evaluated.

•	In 2014, Mikado Pond was dewatered to prevent overtop; sediments were removed to increase
capacity.

•	A time-critical removal action that began in 2015 provided an additional system to drain Greenback Pond
during spring runoff, extended and improved surface water controls, removal of sedimentation from
retention ponds, pumping of ARD retention ponds to prevent overtopping, and pumping water at the Gaw
Shaft through a relief well, and monitoring of the mine pool. Monitoring of mine pool water levels
continues as part of the O&M activities for completed remedy components.

•	Construction of the repository in June 2013; the repository also receives contaminated residential soils
removed from OU9 (See Section XII).

•	The diversion ditch upgradient of the Mikado, RAM and Pyrenees waste rock piles was re-engineered in
2016 that included construction of the Gaw pump house to better divert clean water into No Name Gulch
and, ultimately, into California Gulch. The effectiveness of this diversion is being monitored.

After completion of Phase 1 activities in 2016, the EPA completed a Technical Assessment Report in March 2021
to support Phase 2 (waste rock pile capping) and Phase 3 (resizing of collection channels and ponds) remedial
design and remedial action activities for OU6. The assessment revised the conceptual understanding of the OU6

32

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geology and hydrology based on information obtained during Phase 1 activities to refine the design for the Phase
2 and Phase 3 remedial actions. Recommendations can be found in the report.

In 2020, to meet the requirements of the OU6 decision documents that require institutional controls designed to
protect engineered remedies and to reduce exposure to contaminants left in place, the EPA and CDPHE proposed
an amendment of the Lake County Land Development Code. The amendment is under review. In order for the
remedy to comply with Colorado's Environmental Covenants Act (C.R.S. 25-15-317 to 327), Lake County will
need to enter into an intergovernmental agreement (IGA) granting the State authority to enforce against violations
of the land-use control ordinance. If an IGA is not reached, areas affected by the amended remedy containing
waste left in place or engineered features will need an environmental covenant or restrictive notice as required by
C.R.S. § 25-15-320.

Systems Operations/Operation & Maintenance (O&M)

An O&M Plan for the repository is in place. An O&M Plan for the remaining components is planned.

X.2 OU6: PROGRESS SINCE PREVIOUS FYR

This section includes the protectiveness determinations and statements from the 2017 FYR (Table 12). There
were no recommendations identified from the 2017 FYR.

Table 12: Protectiveness Determinations/Statements from the 2017 FYR

()l #

PmieclheiR'ss
IkUrminiKion

Pmlecliu'iiess Sliiiomonl

Will be Protective

The remedy at OU6 is expected to be protective of human
health and the environment upon completion. Currently,
contaminated surface waters are contained in a series of
retention ponds and/or channeled for treatment at the USBR
Leadville Mine Drainage Tunnel Treatment Plant via the
Leadville Mine Drainage Tunnel.

X.3 OU 6: FIVE-YEAR REVIEW PROCESS

Data Review

The selected remedy for OU6 is for source remediation. No specific numerical performance standards are part of
the RAOs for OU6. The remedy for OU12 is designed to achieve chemical-specific, numerical performance
standards for sitewide surface water and groundwater. Therefore, there were no data to review for OU6.

Site Inspection

The OU6 site inspection took place on June 16, 2022. Participants are listed in Section III of this FYR Report.
Photographs were taken of site features, including monitoring wells and access controls (Appendix G). An
inspection checklist has been completed. It is available in Appendix F.

The site inspection began at the waste soil repository area and associated drainage pond constructed in 2013 to
receive sitewide contaminated soil and sediment. The repository and pond were surrounded by a fence posted
with warning signs. The repository appeared to be in good condition and the sloped sides were reinforced with
rock. The site inspection continued with observations of a number of waste rock piles and associated surface
water retention ponds and extensive surface runoff diversion features throughout OU6. These included the
Pyrenees, RAM, Old and New Mikado, Greenback and Mahalla waste rock piles. Contaminated runoff from these
piles is contained in the surface water ditch system that ultimately channels the runoff via the Leadville Mine
Drainage Tunnel to the USBR plant for treatment. In addition, participants observed the conveyance system
installed as part of the May 2015 time-critical removal action that transports drainage from the Greenback Pond
and Marion Pond to the Robert Emmet Mine Shaft, with ultimate treatment at the LMDT.

-------
Participants observed the Marion, Greenback, Mikado and Adelaide-Ward ponds, which were surrounded by
fencing and warning signs. Due to four years of drought, the water levels in the ponds visited were well below the
berms. An O&M Plan for OU6 is planned. The waste pile caps and the fences around the ponds were in good
condition and signs were legible. Participants observed improvements to the OU6 diversion ditches, which have
been enlarged and reinforced with riprap rock to disperse flow. The Mineral Belt Trail paved path was also
observed and in good condition.

X.4 OU6: TECHNICAL ASSESSMENT

QUESTION A: Is the remedy functioning as intended by the decision documents?

The OU6 remedy is in the process of being fully implemented. When complete, the remedy is anticipated to
function as intended by site decision documents. The primary objective of the OU6 remedy is to minimize the
volume of ARD that can impact surface water and groundwater. Many waste rock piles are located in OU6. In the
1990s, several piles were capped. Surface water retention and diversion channels to contain ARD were
constructed. Retention ponds capture ARD from the piles. An overflow system channels contaminated surface
water through a series of retention ponds and through the LMDT to the USBR Leadville Mine Drainage Tunnel
Treatment Plant.

The 2010 OU6 AROD outlines a phased approached to reducing ARD in OU6. Phase 1, the enhancement to the
diversion ditch upgradient to the Greenback, RAM, and Old and New Mikado waste rock piles, was completed in
2016. The Gaw shaft relief well, in conjunction with USBR treatment plant operations, is used to manage water
levels in the mine pool. The USBR is in the process of building a new treatment plant in the footprint of the
existing plant. Construction is planned over several years. The EPA completed a technical assessment of OU6 in
March 2021 to support Phase 2 (waste rock pile capping) and Phase 3 (resizing of collection channels and ponds)
remedial design and remedial action activities for OU6.

The city of Leadville's 2013 ordinance serves as an institutional control for Starr Ditch, a portion of OU6 in
Leadville. In addition, areas of OU6 are zoned for industrial mining and business uses. Procedures are also in
place to notify the EPA and CDPHE should local governments approve a change in land use. More institutional
controls through amendments to the Lake County Land Development Code and establishment of resolutions and
ordinances are being considered to protect engineered remedies and to reduce unacceptable exposures to
contaminated soils in the event the zoning changes to residential.

QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of the
remedy selection still valid?

The 2003 OU6 ROD did not establish numeric cleanup standards for surface water or groundwater. The
RAOs identified in the 2003 OU6 ROD included controlling erosion of contaminated materials into local water
courses, controlling the leaching and migration of contaminated materials into surface water and groundwater, and
preventing direct unacceptable exposures to elevated concentrations of contaminants in soil and waste rock. Due
to the volume of ARD generated at OU6 and the continued deterioration of the mine workings and
Leadville Mine Drainage Tunnel, a 2010 AROD modified the remedy to allow for more efficient progress and
long-term maintenance of these RAOs. Remedial design activities are underway.

QUESTION C : Has any other information come to light that could call into question the protectiveness of the
remedy?

No other information has come to light that could call into question the protectiveness of the remedy.

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X.5 OU6: ISSUES/RECOMMENDATIONS

Issues/Recommendations

()l (s) without IsMics/kiTomiiK'iHlalions Identified in the l-'Yk:

None

OU(s):

Issue Category: Institutional Controls

Issue: Institutional controls are a component of the selected remedy but have not
yet been implemented.

Recommendation: Finalize additional institutional controls as appropriate.

Affect Current
Protectiveness

Affect Future
Protectiveness

Party Responsible

Oversight Party

Milestone Date

Yes

Other/Lake County

EPA/State

12/30/2024

X.6 OU6: PROTECTIVENESS STATEMENT

Protectiveness Statement(s)

Operable Unit: Protectiveness Determination:

6 Will be Protective

Protectiveness Statement: The remedy at OU6 is expected to be protective of human health and the environment
upon completion. Currently, surface water is diverted and contaminated surface waters are contained in a series
of retention ponds and/or channeled for treatment at the USBR Leadville Mine Drainage Tunnel Treatment Plant
via the Leadville Mine Drainage Tunnel. The area is zoned industrial mining. Additional institutional controls are
being considered.

XL OU7: APACHE TAILING IMPOUNDMENTS

OU7, the Apache Tailing Impoundments, consisted of four distinct tailings impoundments on the southern edge of
Leadville, adjacent to U.S. Highway 24 (Figure D-8). These impoundments were located in California Gulch,
about 1,500 feet downstream from the Yak Tunnel WTP surge pond.

Tailings, placed in the Main Impoundment and possibly the North Impoundment, were generated by a mill on the
hillside northeast of the Apache Tailing Impoundments. The mill was also known as the Venir Mill, the California
Gulch Mill and the ASARCO Incorporated Leadville Milling unit. Available historical information indicates this
mill operated between 1939 and 1956. It produced about 630,000 cubic yards of tailings in the 11.3-acre Main
Impoundment and an estimated 14,500 cubic yards of tailings in the 1.8-acre North Impoundment.

The Apache Energy & Minerals Company operated the Apache Mill from the late 1970s into the 1980s. The
Apache Mill reprocessed tailings from the Main Impoundment and deposited remaining materials into Tailing
Pond No. 2 and Tailing Pond No. 3, which were located west and downstream of the Main Impoundment, and
were about 1.5 acres and 0.5 acres in size, respectively. Tailing Ponds No. 2 and No. 3 were consolidated into the
Main Impoundment as part of a removal action in 1997.

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XI. 1 OU7: RESPONSE ACTION SUMMARY

Basis for Taking Action

The preliminary 1991 risk assessment evaluated residential risks from exposure to contaminated media. Since the
completion of the preliminary 1991 risk assessment, several studies were completed that provided more
data on contaminant concentrations, and human and ecological exposures. The 2000 Final Focused Feasibility
Study (FFS) assessed the general conditions of the Apache Tailing Impoundments area and evaluated the nature
and extent of contamination in OU7. Arsenic, cadmium, lead and zinc were identified in the FFS as potential
COCs for the evaluation of the remedial alternatives. Arsenic and lead were used as indicator contaminants for
risk in the final risk assessment. These contaminants were selected based on the results of the preliminary risk
assessment, which indicated that lead and arsenic were responsible for most human health risks at the Site.

The preliminary 1991 risk assessment identified potential primary sources of metals of concern, the mechanisms
of release to the environment, and receptors, in a Conceptual Site Model. The final 1995 risk assessment
identified soil ingestion as the exposure pathway of concern for recreational visitors; ingestion of soil and dust
was identified as the exposure pathway of concern for commercial/industrial workers. Exposure to other media
(e.g., slag piles) and exposure to soil/dust through other pathways (e.g., dermal exposure) are considered to be an
insignificant concern for workers and recreational users. The source materials identified at OU7 include tailings
and foundation soils (Table 13). These source materials are not considered to be principal threat wastes. Appendix
B (Table B-10) provides a chronology of OU7 events.

Table 13: Contaminated Media, OU7

Media

Conlaminalion

Tailings

Weathered sulfidic tailings on the surface of the North Impoundment and Main Impoundmeni
contains elevated lead and arsenic concentrations and has a high acid-generating potential.

Dark gray sulfidic tailings occurs below the weathered sulfidic tailings on the North
Impoundment and Main Impoundment and contain elevated lead and arsenic concentrations.

Brown oxide tailings found only on the Main Impoundment contains elevated lead
concentrations and arsenic concentrations lower than those concentrations found in sulfidic
tailings. Brown oxide tailings has a significant neutralization potential, counteracting acidic
sulfidic tailings leachate.

Soil

Foundation soils found at both the Main Impoundment and North Impoundment contain
elevated lead concentrations and slightly elevated arsenic concentrations.

Response Actions

Multiple removal actions took place at OU7 between 1996 and 2000 (Table B-l 1). Removal actions completed
included removal of Tailing Pond No. 2 and Tailing Pond No. 3, consolidation of material removed from Tailing
Pond No. 2 and Tailing Pond No. 3 on the Main Impoundment, and placement of erosion protection along the toe
of the southwest embankment of the Main Impoundment below the clay-tile culverts and wooden box culvert
outfalls. The December 1997 Removal Action Completion Report describes the construction activities in greater
detail.

The EPA issued the ROD for OU7 on June 6, 2000, outlining the selected remedy for OU7. The OU7 remedy was
selected to eliminate or reduce potential threats to humans and the environment through the construction of a soil
cover with a geosynthetic barrier and revegetation, followed by implementation of institutional controls and a
Long-Term Monitoring Plan. A clarification of the types of institutional controls needed was documented in a
memo to the file and was signed by the EPA on May 16, 2013.

The RAOs identified in the OU7 ROD for the Apache Tailing Impoundments were:

• Control airborne transport of tailings particles

• Control erosion of tailings materials and deposition into local water courses

-------
•	Control leaching and migration of metals from tailings into surface water and groundwater
The selected remedy for OU7 included the following components:

•	Surface water controls, including the channelization of California Gulch through the southern part of
the Main Impoundment and diversion ditches to provide surface water run-on and runoff control

•	Application of source surface controls to the impounded tailings, consisting of regrading the
impoundment, placing a multi-layer composite cover over the combined tailings area, and revegetating
the covered surface

•	Institutional controls to warn of potential hazards and to maintain the effectiveness of the remedy by
limiting access to or use of the property (current and future use scenarios), including temporary and
permanent measures

•	A long-term monitoring program to assess the quality of surface water and groundwater after
implementation of the remedy

Per the ROD, the O&M program was developed during the remedial design. It involved vegetation monitoring,
inspecting and maintaining the cover and surface water controls, and identifying areas showing evidence of
erosion or differential settlement of the cover.

The 2000 OU7 ROD did not contain numeric cleanup standards, but was meant to address potential source
material contributing to surface water, groundwater and air contamination. The OU12 remedy addresses sitewide
surface water and groundwater contamination to monitor the effectiveness of the source control remedies.

Status of Implementation

The majority of construction activities for the final remediation occurred from June through December 2001 at
which time construction activities were temporarily suspended for the winter. Earthwork and revegetation
activities recommenced with a different contractor at the end of September 2002 and continued into November
2002. Maintenance activities were conducted over a period of several weeks during September 2003. A summary
of completed activities includes:

•	Installation and maintenance of temporary sediment, diversion and storm water control structures in
accordance with the Storm Water Management Plan and maintenance of such controls during
construction activities

•	Provision of dust control, as necessary, during all excavating, hauling and placing operations

•	Excavation of dispersed tailings and soil adjacent to the Main Impoundment to allow for the construction
of temporary sedimentation ponds

•	Demolition of existing concrete foundations west of the Main Impoundment

•	Relocation of a section of sanitary sewer line around the North Impoundment, connection to an existing
sewer line at the east and west ends, including two new sewer lateral connections and abandonment of
existing manholes and sewer line.

•	Regrading of the tailings impoundments as indicated on the drawings and placement of excavated
material in fill areas between the Main and North Impoundments and on top of the Main Impoundment

•	Removal and replacement of the overhead power line running east and west between the Main and North
Impoundments

•	Channelization of California Gulch through the southern portion of the Main Impoundment

•	Installation of the multi-layer cover system consisting of a geosynthetic clay liner, geocomposite drainage
layer, and an 18-inch soil cover over the regraded tailings impoundments

•	Construction of permanent diversion ditches, berms and swales with appropriate erosion protection to
provide surface water run-on and runoff control

•	Extension or abandonment of monitoring wells or piezometers, as necessary

•	Revegetation of the tailings impoundments and other disturbed areas with specified seed mixture.

•	Site cleanup and demobilization

37

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0U7 achieved remedial action project completion status on December 17, 2003.

On December 22, 2010, Lake County implemented institutional controls for OU7 in the form of a resolution
amending the Lake County Land Development Code and adopting regulations that protect both engineered and
non-engineered remedies at OU7. A best management practice handout is provided to all applicants applying for a
building permit within OU7. In addition, any disruption of engineered or non-engineered remedies within OU7
requires written approval from CDPHE. The city of Leadville adopted a similar ordinance on May 7, 2013.

The EPA partially deleted OU7 from the NPL on October 24, 2014.

Systems Operations/Operation & Maintenance (O&M)

CDPHE conducts annual O&M inspections and maintenance activities, per the October 2016 O&M Plan.
Performed by the State of Colorado under an EPA grant funded with Special Account monies, O&M activities
include inspection and maintenance of the covers and surface water controls. As a result of the September 2021
inspection, TetraTech, the state O&M Inspection contractor, made several recommendations to improve the
functionality and longevity of various remedy components. The O&M issues identified do not currently present
concerns for the remedy's protectiveness. CDPHE in consultation with EPA will determine which of these
recommendations will be implemented as part of O&M activities. A summary is provided as follows:

Apache Tailings Impoundment (ATI) Area CDPHE O&M Contractor Recommendations

• Continue to monitor erosion feature located on the northern portion of the site

• Continue to monitor animal burrows on the southwest corner of the impoundment

• Have a comprehensive vegetation inspection performed by a certified specialist

• Transplant trees growing on the remedy (e.g., cap and channels)

• Reshape the eastern channel to properly convey flows through the rundown channel

• Reshape the riprap at the base of the southwest drainage channel to facilitate flow. Excess riprap can be
placed in areas where geotextile fabric is visible within the channel.

• To prevent interference with flow conveyance, remove trees inside of the channel system and transplant
them elsewhere (not on the cap).

• Remove sediment and vegetation to facilitate drainage through the easternmost culvert on-site

• Clean the Starr Ditch culvert approach and trash rack to facilitate drainage

• Plug the borings in the cap of the impoundment with low permeability material to re-establish the
integrity of the engineered cap as part of the routine O&M

• Contact the landowner to relocate the liquid containers from the southeastern corner of the OU boundary
to an area less susceptible to flooding

XI.2 OU7: PROGRESS SINCE PREVIOUS FYR

This section includes the protectiveness determinations and statements from the 2017 FYR Report (Table 14).
There were no recommendations identified from the 2017 FYR Report.

Table 14: Protectiveness Determinations/Statements from the 2017 FYR Report

()l #

I'mlwlheness
l)i-UTiiiin;ilion

Pmlecli* cness Si;ilonioiH

Protective

The remedy at OU7 is protective of human health and the environment.
No completed human or ecological exposure pathways were identified.
Institutional controls are in place. CDPHE ensures that the remedy
remains functioning as intended through routine O&M activities.

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XI.3 OU7: FYR PROCESS

Data Review

There are no applicable data to review for 0U7.

Site Inspection

The OU7 site inspection took place on June 22, 2022. Participants are listed in Section III of this FYR
Report. The OU7 capped surface was in good condition with a vegetated cover. This area is used by Lake County
for excess snow disposal. Photographs were taken of site features, including the Apache Tailing Impoundments
(Appendix G). An inspection checklist has been completed. It is available in Appendix F. The Apache Tailing
Impoundments were intact and had a well-established vegetated cover.

XI.4 OU7: TECHNICAL ASSESSMENT

QUESTION A: Is the remedy functioning as intended by the decision documents?

Response actions included the installation and maintenance of surface water diversion and stormwater control
structures, excavation, consolidation and capping of tailings and contaminated soil, construction of sedimentation
ponds, demolition of existing concrete foundations, relocation of utilities, regrading of the tailings impoundments.
A review of documents and site inspections indicate that the remedy is functioning as intended by the OU7 ROD.

Sitewide surface water and groundwater in the vicinity of OU7 is being addressed as part of OU12. The annual
O&M review provides information to evaluate the stability, functionality and continued protectiveness of the
remedy. The recommendations are addressed as part of the regular O&M activities and CDPHE addresses any
maintenance and repairs to ensure the functioning of the remedy. All institutional controls required by site
decision documents are in place. The EPA and CDPHE will be notified if local governments approve a change in
land use. The EPA partially deleted OU7 from the NPL on October 24, 2014.

QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of the
remedy selection still valid?

There have been no changes to the ARARs identified in the ROD or since the previous FYR. No newly
promulgated standards have been identified that could call into question the protectiveness of the remedy as
implemented (see Appendix H for detail). There have been no other changes in exposure assumptions to human
health and the environment or toxicity data that would call into question the protectiveness of the remedy. There
are currently no proposed reuse plans for OU7 that would affect the protectiveness of the remedy.

QUESTION C : Has any other information come to light that could call into question the protectiveness of the
remedy?

No additional information has come to light that would call into question the protectiveness of the remedy.

XI.5 OU7: ISSUES/RECOMMENDATIONS

Issues/Recommendations

()l (s) without Issues/Recommendations Identified in (lie I YR:

OU7

OTHER FINDINGS

-------
Review, assess and implement as appropriate the recommendations in the 2021 O&M OU2, 5 and 7 Inspection
Report.

XI.6 OU7: PROTECTIVENESS STATEMENT

Protectiveness Statement(s)

Operable Unit: Protectiveness Determination:

7 Protective

Protectiveness Statement: The remedy at OU7 is protective of human health and the environment. No
completed human or ecological exposure pathways were identified. Institutional controls are in place.
CDPHE ensures that the remedy remains functioning as intended through routine O&M activities.

XII. OU8: LOWER CALIFORNIA GULCH

OU8 is defined as the 500-year floodplain of California Gulch, from immediately below the boundary of the Yak
Tunnel WTP (OU1) to California Gulch's point of confluence with the Arkansas River (Figure D-9). OU8 also
includes the CZL Tailing Impoundment, which is located outside of the 500-year floodplain. OU8 is about 97
acres in size and 4.3 miles long. Lower California Gulch receives runoff and water from tributaries that drain all
or parts of upgradient OUs. Lower California Gulch also receives tributary water from Upper California Gulch
and Stray Horse Gulch via Starr Ditch that drain areas of OU4 (Upper California Gulch) and OU6 (Stray Horse
Gulch/Evan Gulch watersheds). The land area within OU8 is mostly private property. Highway bridges, road
crossings and culverts are located within the 500-year floodplain of Lower California Gulch. Lower California
Gulch roughly parallels U.S. Highway 24.

Appendix D contains detailed maps for OU8 areas: Fluvial Tailing Site (FTS) 1 and FTS 2, the CZL Tailing
Impoundment, FTS 3, FTS 8 and non-residential soils, FTS 6, the Gaw Waste Rock Pile and non-residential soils
(Figure D-10). The land surrounding and within OU8 is zoned for industrial mining or business.

OU8 consists of a former placer and tunnel mining area. Fluvial deposits of tailing occurred as tailings were
released from impoundments. Waste rock from underground mining was frequently dumped near mine shafts, as
was the case with the Gaw Waste Rock Pile. During high-flow events, stream sediments originating from source
areas primarily upstream of OU8 are transported by California Gulch and associated tributaries into and within
OU8. The soluble metals contained in runoff have contributed to the contamination of surface water and
sediments.

The CZL Tailing Impoundment is about 1 mile west of Leadville and immediately north of the Stringtown Mill
Area. The CZL site was an operating flotation mill operation that covered about 1.6 acres at an average depth of 7
feet. The operation processed zinc-lead ores sporadically between 1925 and 1940. The CZL Tailing Impoundment
contained an estimated 17,000 cubic yards of tailings.

Non-residential area soils are defined as poorly vegetated areas outside of the fluvial tailings sites and within the
OU8 boundary. The studies identified about 6.3 acres of non-residential area soils with elevated levels of
contaminants.

Appendix C provides more background information on OU8.

XII. 1 OU8: RESPONSE ACTION SUMMARY

Basis for Taking Action

Several studies and RIs have been conducted addressing Lower California Gulch (OU8). The following areas
were identified as potential contaminant sources in OU8: areas of impounded tailings in the CZL Tailing

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Impoundment located in the California Gulch 500-year floodplain, waste rock in the Gaw Waste Rock Pile,
fluvial tailings in five fluvial tailings sites, non-residential area soils, and stream sediments. Table 15 lists
contaminated media and potential contaminant sources at OU8. Appendix B (Table B-12) provides a chronology
of OU8 events.

Table 15: Contaminated Media, OU8

Modiii

Coiiiiiiniiiiiiidii

C/.l. Urn ml killings

impoundment

1 !le\ ;ilcd coiiccuimiious of lc;id, cadmium, mscuic mid /inc, w illi ilie polcniml lo genomic
ARD.

Non-residential soils

Metals concentrations are generally low and decrease with depth to native, undisturbed
soils.

Gaw Waste Rock
Pile

Surface soil contained lead at slightly elevated concentrations. Outflow from the Gaw
shaft demonstrated neutral pH values, with minimally elevated sulfate concentrations.
Metals levels were typically below limits of detection.

FTSs 1, 2 and 3

Surface tailings had elevated levels of arsenic, cadmium, lead and zinc. Subsurface
tailings had elevated levels of arsenic, cadmium and lead. Foundation soils had elevated
levels of silver, cadmium, arsenic, lead and zinc.

FTS6

Surface tailings had elevated levels of arsenic, cadmium, copper, lead, mercury, silver and
zinc. Subsurface tailings had elevated levels of arsenic, cadmium, copper, lead,
manganese, mercury and zinc. Foundation soils had elevated levels of silver, cadmium,
copper, arsenic, lead and zinc. The waste pile has the potential to generate ARD.

FTS8

Surface tailings had elevated levels of arsenic, cadmium, copper, lead and zinc.
Subsurface tailings had elevated levels of arsenic, cadmium, lead and zinc. Foundation
soils had elevated levels of cadmium.

Stream sediment

Elevated levels of arsenic, cadmium, lead, copper and zinc.

Response Actions

To take advantage of the availability of the Oregon Gulch Tailing Impoundment in OUIO as a repository for
contaminated materials from OU8, two interim removal actions were approved for OU8 in 1995 and 1998. In the
first interim removal action, about 28,000 cubic yards of material were excavated from the CZL Tailing
Impoundment, the western portion of FTS2, and the underlying foundation soils and placed in the Oregon Gulch
Tailing Impoundment (OUIO). The excavated area was backfilled with clean borrow soil, graded and vegetated.
Wetlands adjacent to the CZL Tailing Impoundment site were revegetated in summer 1996. In the second interim
removal action, about 5,794 cubic yards of fluvial tailings were excavated from poorly vegetated, erosion-prone
areas in OU8 (specifically, FTS2, FTS3, FTS6 and FTS8). The excavated tailings were transported and placed in
the Oregon Gulch Tailing Impoundment (OUIO). In conjunction with channel excavation under the second
interim removal action, about 1,339 cubic yards of sediment were removed from accumulated sediment in FTS2
and FTS3. The excavated stream sediment was transported and placed in the Oregon Gulch Tailing Impoundment
(OUIO). Resurrection conducted both removal actions under EPA oversight.

The EPA issued the ROD for OU8 on September 29, 2000. The ROD established the following RAOs:

• Control airborne transport of tailings particles and contaminated non-residential soils

• Control leaching and migration of metals from tailings, soil, waste rock, and contaminated fluvial and
stream sediments into surface and groundwater

• Control erosion of tailings material and soil materials into local water courses

• Control contaminant exposure to animals and aquatic life

The selected remedies for addressing the contaminated media within OU8 are described below.

• CZL Tailing Impoundment. No further action was the selected alternative for impounded tailings within
OU8. All tailings were removed from the CZL Tailing Impoundment site during the 1995 removal action.
No other impounded tailings exist within OU8.

-------
• Non-Residential Area Soils: Containment was the selected alternative for non-residential area soils in
OU8. Non-Residential Area Soils were to be regraded to promote positive drainage, with addition of soil
amendments and revegetation to follow. Institutional controls are required.

• Gaw Waste Rock: No action was the selected alternative for waste rock in OU8. No action was selected
since sitewide studies and remedial investigations showed that the Gaw Waste Rock Pile was not a source
of contamination to surface water or groundwater.

• Fluvial Tailing Sites (FTS): Containment was the selected alternative for fluvial tailings in OU8. This
alternative consisted of regrading, revegetation, riprap or erosion-control matting in erosion-prone areas
of fluvial tailings, and institutional controls.

• Stream Sediment: Sediment removal and channel reconstruction was the selected alternative for stream
sediment in OU8. This alternative consists of reconstruction of unstable braided channel areas of FTS3,
construction of a channel through FTS6, removal of sediment and channel improvements in erosion-prone
areas, and institutional controls.

The 2000 OU8 ROD did not contain numeric cleanup standards but was meant to address potential source
material contributing to surface water and groundwater contamination. The OU12 remedy addresses sitewide
surface water and groundwater contamination to monitor the effectiveness of the source control remedies.

Status of Implementation

Resurrection completed all OU8 remedial actions in September 2003. Remedial actions included regrading of
non-residential soils and FTSs 1, 2, 3, 6 and 8 to promote positive drainage. Soil amendments were added to the
regraded areas to promote reestablishment of vegetation, and native wetland plant species were planted along
wetland areas. Additional efforts were made to control erosion at the FTSs, including placement of riprap, gabion
baskets and 2,400 linear feet of filter fabric at erosion-prone areas along California Gulch.

An area of California Gulch that has been geomorphically unstable and extended through braided channels across
FTS3 was reconstructed to divert flow to the south channel. A channel was also constructed through FTS6 to
preserve the 500-year floodplain so that it may continue to convey and store floodwaters. Sediment excavation
cleared the channel at Removal Site 12 in FTS2 and in other erosion-prone areas of the channel. Channel
improvements stabilized the banks on either side of the channel path.

The remedies met the RAOs, since materials were excavated and removed from OU8, by preventing the release of
waste material or by containing the contaminated materials, and by controlling the release of waste material to air
and water.

In addition, Lake County passed an ordinance on March 2, 2009, that established institutional controls for OU8
(Appendix K). Under this ordinance, the fluvial tailings sites, non-residential soils and constructed elements of the
remedies within OU8 are designated as engineered remedies, and the county will not issue a permit for any
activity on property that contains a designated engineered remedy unless the permit applicant has secured
approval for those activities from CDPHE. For all other parts of OU8 not designated as part of an engineered
remedy, the ordinance provides that any excavation or other earth removal activity that exceeds 10 cubic yards
requires CDPHE approval for such activity as a condition precedent to the county granting a permit. Finally, the
ordinance provides that all permit applicants shall be provided with information regarding best management
practices for potentially contaminated soils and the applicant must certify they have received and reviewed this
information before a permit will be issued. The City of Leadville adopted a similar ordinance for properties in
OU8 within city limits on May 7, 2013. In addition, Newmont/Resurrection recorded environmental covenants on
its OU8 properties on July 31, 2012, and October 1, 2012, that further prohibit residential use and restrict
groundwater use.

All remedial actions have been completed. Long-term monitoring and maintenance activities are underway. The
EPA partially deleted OU8 from the NPL on January 12, 2010.

Systems Operations/Operation & Maintenance (O&M)

-------
Newmont/Resurrection conducts inspections in accordance with the OU4, 8 and 10 O&M Plan, California Gulch
Superfund Site, which is Appendix D to the 2008 Consent Decree approved in August 2008. The EPA approved a
minor modification to the O&M Plan in 2018 that reduced the frequency of inspections at OU8 from biannually to
every five years. The inspection findings are documented in the Annual California Gulch Superfund Site OU4,
OU8 and OU10 inspection reports. These reports are available by contacting EPA Region 8.

The following areas in OU8 are inspected:

• FTS1 revegetated tailings and reinforced embankment

• FTS2 reinforced streambanks and revegetation

• FTS3 reconstructed stream channel, reinforced streambanks and revegetation

• FTS6 reconstructed stream channel, Apache/California Gulch Transition and revegetation

• California Gulch reinforced streambank near the Cloud City Ski Club

• California Gulch reinforced streambank near the Airport Gulch

• Revegetated non-residential soils areas

Maintenance activities during the current FYR period have included repairs to gabion baskets, stabilization of
channel banks in erosion-prone areas, revegetation of barren surfaces and construction of a ditch to drain run-on
water that had been ponding on the surface of tailings at FTS 1.

XII.2 OU8: PROGRESS SINCE PREVIOUS FYR

This section includes the protectiveness determinations and statements from the 2017 FYR Report (Table 16).
There were no recommendations identified from the 2017 FYR Report.

Table 16: Protectiveness Determinations/Statements from the 2017 FYR Report

()l #

PmU'iiiteiiess
lk'Urniin;i(ion

ProU'Clheiiess Si;ilonioin

Protective

The remedy at OU8 is protective of human health and the
environment. No complete human or ecological exposure
pathways were identified. Institutional controls are in place and
the remedy is functioning as designed.

XII.3 OU8: FYR PROCESS

Data Review

No data from OU8 were available for review.

Site Inspection

The OU8 site inspection took place on June 22, 2022. Participants are listed in Section III of this FYR
Report. OU8 extends along the lower reaches of the California Gulch between OU1 and OU11. Site inspection
participants observed portions of California Gulch to look at riprap and other erosion-control mechanisms
installed along erosion-prone areas of the channel. Participants also observed the stabilized tailings sites and
reinforced embankments. Site inspection observations were documented in the inspection checklist. Site
photographs are included in appendices F and G, respectively.

XII.4 OU8: TECHNICAL ASSESSMENT

QUESTION A: Is the remedy functioning as intended by the decision documents?

The site inspection and the review of documents, ARARs and risk assumptions indicate that the OU8 remedy has
been completed and is functioning as intended by site decision documents. Excavation of fluvial tailings, waste
rock, non-residential soil and stream sediments was finished in 2003. Continued maintenance and monitoring

-------
ensure that excavated piles of contaminated materials are stable and do not present a risk of metals loading to
California Gulch. All institutional controls required by the decision documents are in place. The EPA and CDPHE
will be notified should local governments approve a change in land use. Newmont/Resurrection is responsible for
continued O&M activities for OU8. After implementation of all remedial components and achievement of all
RAOs, the EPA partially deleted OU8 from the NPL on January 12, 2010.

QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of the
remedy selection still valid?

The 2000 OU8 ROD addressed potential source material contributing to surface water and groundwater
contamination at OU8. It did not contain numeric cleanup standards for surface water or groundwater. The OU12
remedy addresses sitewide surface water and groundwater contamination.

All the RAOs identified in the 2000 OU8 ROD have been achieved. Vegetation of the contaminated material pile
surfaces controls airborne transport, erosion, and exposure of animals and aquatic life to contamination. Land use
at OU8 has not changed. The exposure assumptions used in the development of the 2000 OU8 ROD remain valid.
There have been no changes to the ARARs identified in the ROD or since the previous FYR. No newly
promulgated standards have been identified that could call into question the protectiveness of the remedy as
implemented.

QUESTION C : Has any other information come to light that could call into question the protectiveness of the
remedy?

No additional information has come to light that would call into question the protectiveness of the remedy.

XII.5 OU8: ISSUES/RECOMMENDATIONS

Issues/Recommendations

()l (s) without Issiies/Reconinieiulntions Identified in (ho I YR:

OU8

XII.6 OU8: PROTECTIVENESS STATEMENT

Protectiveness Statement(s)

Operable Unit: Protectiveness Determination:

8 Protective

Protectiveness Statement: The remedy at OU8 is protective of human health and the environment. No
complete human or ecological exposure pathways were identified. Institutional controls are in place
and the remedy is functioning as designed.

XIII. OU9: RESIDENTIAL POPULATED AREAS

OU9 includes residential area soils in those parts of the Site where the land use is residential or that were zoned as
residential/populated areas and as low-density residential areas on or before September 2, 1999 (Figure D-l 1).
Residential area soils are defined in the 1994 Consent Decree with ASARCO Incorporated as soils in the
residential area of the Site that may have been impacted by past smelting and mining activities. This encompasses
the city of Leadville, Stringtown and outlying areas zoned for residential use. Included are residential properties,
yards, parks, vacant lots, schoolyards, playgrounds and community use areas, including unpaved streets and

-------
alleys. For ease in determining compliance with blood monitoring performance standards, OU9 was
geographically divided into statistical subunits A through G. In addition, OU9 includes 38 mine waste piles
located in populated areas of eastern Leadville. Appendix C provides more information about OU9.

XIII. 1 OU9: RESPONSE ACTION SUMMARY

Basis for Taking Action

Numerous risk assessments were conducted. They included Baseline human health risk assessments (BRAs) (part
A, part B and part C), an ecological risk assessment for Terrestrial ecosystems, a surface water human health risk
assessment, a groundwater baseline human health risk assessment, and a baseline aquatic ecological risk
assessment.

The BRAs concluded that lead was the only COC for OU9 based on lead models and blood-lead monitoring. The
non-lead metals (including arsenic and manganese) in residential soils do not pose a significant health risk to
residents. These results were supported by a large body of site-specific data. Included were:

• Extensive measurements of lead in soil and dust in residential locations

• An extensive demographics survey

• Data on lead levels in water and paint (both interior and exterior)

• Data on the physical and chemical forms of lead at various locations around the community

• An informative community-wide blood lead study involving 314 children (about 65% of the total
population of children at the Site)

These data were used to support two parallel lines of investigation and assessment. The first of these
investigations and assessments employed the EPA's Integrated Exposure Uptake and Biokinetic Model (IEUBK)
to calculate the expected impact of lead levels in soil and dust on blood lead levels in area children. The second
approach compared the measured blood lead values in area children with relevant national blood lead statistics to
help evaluate the current effects of actual site exposure to lead.

The Final Residential Soil FS Report, completed in November 1998, evaluated seven remedial alternatives to
address the residential soils of properties, yards and open-space areas within OU9 where lead levels exceeded the
trigger level of 3,500 mg/kg. The selected FS alternative was the Lake County Community Health Program
(LCCHP), a revised version of the Kids First program used during the interim response. The LCCHP combined
blood lead monitoring, education, community awareness and residence-specific response actions to reduce the
potential for children to be exposed to lead in Leadville and surrounding areas. This program addressed lead in
soil and dust, interior and exterior paint, plumbing fixtures, and dietary and household sources. O&M activities
include LCCHP Phase 2 administration, which includes the community outreach and education program, and the
blood lead monitoring program, along with investigation and remediation activities. Appendix B (Table B-13)
provides a chronology of OU9 events.

Response Actions

Under the Kids First program, time-critical removal actions took place from October 1995 to April 2000. Under
the LCCHP, response actions were completed for multiple residences, commercial properties and vacant lots from
April 2000 to summer 2009.

From October 1995 to summer 2009, 1,040 properties were investigated. Of those properties, 270 required a soil
removal action. Forty properties, which may or may not have had soil removals, have had dust removed or paint
repaired/replaced. The EPA conducted the last property assessment and response actions in summer 2009.
Subsequent investigations and remediations are performed by the LCCHP Phase 2 Workgroup. Appendix B,

Table B-13 provides a complete history of early initial response actions.

Signed on September 2, 1999, the EPA signed a ROD for OU9 and selected a remedy to address the lead
contamination. The purpose of this response action is to reduce the risk of lead exposure to children in residential

-------
areas. The selected remedy created the LCCHP with institutional controls to ensure the effectiveness of the
LCCHP. The intention was for the LCCHP to take the place of the Kids First program. The OU9 remedy was
selected to eliminate or reduce potential threats to humans and the environment posed by concentrations of lead in
soil, dust, paint and water that exceed a specific set of trigger criteria.

The RAOs for OU9 were set in the 1999 ROD, in accordance with the 1994 EPA lead guidance that stated that
the EPA should "limit exposure to soil lead levels such that a typical (or hypothetical, potentially exposed) child
or group of similarly exposed children would have an estimated risk of no more than 5% of exceeding the 10
(ig/dL [micrograms per deciliter] blood lead level."

The RAOs were identified as follows:

• No more than 5 percent of children (age 0 to 72 months) who live at the Site, either now or in the future,
will have blood lead values exceeding 10 (ig/dL.

• Health will be adequately protected if the highest risk level at any sub-location (e.g., a yard for a private
residence) is a probability no higher than one percent that a population of children (age 0 to 72 months)
residing at that sub-location will exceed a blood lead values exceeding 15 (ig/dL.

• Reduce direct exposure of lead incurred by children, which will result in optimal risk reduction through
effective use of resources.

In the 1990s, the EPA-Headquarters-approved LCCHP was considered a "pilot project" that involved a number of
innovative approaches. The program was evaluated by a group of outside scientists and included ongoing review
to ensure that the program was operating as intended and that human health was being protected adequately. The
ongoing review included the establishment of performance standards that, when met, would indicate the
successful completion of the LCCHP and the beginning of O&M activities. The performance standards were
specified in a July 2002 addendum to the OU9 remedial design and are summarized in the 2002 Final Methods
and Standards for Evaluating the Performance of the LCCHP.

The EPA issued an ESD on September 30, 2009. It included the need for institutional controls for the mine waste
piles left in place in OU9. The ESD RAOs are:

• Prevent construction of any type of residential dwelling or facility for human occupancy on the mine
waste piles unless appropriate plans are approved by the EPA or CDPHE

• Maintain the integrity of current or future remedies

Status of Implementation

The LCCHP was implemented as required by the ROD and the Lake County's 2002 Methods and Standards for
Evaluating the Performance document. ASARCO continued to execute the LCCHP until July 2005, when
ASARCO declared bankruptcy, after which the EPA managed the LCCHP soil investigations and cleanups until
2009. The OU9 Work Group manages the program now, as described below.

Data were collected, evaluated and documented in annual reports beginning in 2002 to determine the effectiveness
of the program. The results were analyzed, compared to the performance standards, and expressed as goals for
blood lead levels in children. During 2005, the performance standards established by the EPA for the selected
remedy were met. This conclusion is supported and documented in the 2005 LCCHP Annual Report, dated April
5, 2006. Property owners were given a final chance to have their properties investigated and cleaned up after
performance standards of the LCCHP Phase 1 were met. In 2009, 199 properties were investigated. Thirty-one
properties had areas that exceeded the 3,500 mg/kg action level for lead. These properties were remediated if the
property owners consented.

On March 15, 2010, Lake County passed a resolution (Appendix K) approving the LCCHP Phase 2 Work Plan
and adopting the LCCHP Phase 2 as the institutional control for OU9, which transitioned the OU into the O&M

-------
phase. The county's actions represented the completion of remedial actions for OU9. The LCCHP Phase 2 Work
Plan was also designed as the long-term O&M plan for OU9. The OU9 Work Group, which consists of Lake
County, CDPHE and the EPA, administers, manages and oversees the LCCHP Phase 2 program. The Work
Group approved the LCCHP Phase 2 Work Plan in 2009; the Work Group revised the Work Plan in October
2013.

The OU9 Work Group follows the LCCHP Phase 2 Work Plan. If a blood test indicates an elevated blood lead
level, Lake County Public Health makes follow-up appointments to provide education and counseling to families
and to evaluate the possible sources of lead at each household. The OU9 Work Group reviews results of the home
visit and determines if a formal environmental investigation is warranted. The OU9 Work Group can approve
remediation at a property if an environmental investigation demonstrates that OU9 Trigger Criteria for lead is
being exceeded, or at their discretion. The criteria in the Work Plan were approved in 2009 and revised in 2013
based on updated information regarding lead toxicity.

The lead cleanup at the Site is being implemented in line with the LCCHP Phase 2 Work Plan, which integrates
the EPA's 1994 and 1998 soil lead guidance documents. However, since 1998, the EPA's OLEM has completed a
number of directives which updates the scientific considerations to be used at lead cleanups. The updates
highlight current science and risk assessment tools that the EPA may consider when implementing lead cleanups.
The EPA recognizes this and uses the LCCHP Phase 2 approach which reflects a multi-pathway, community-
based education and outreach approach to identifying sources of lead and exposure pathways in Leadville. The
EPA will continue to evaluate the LCCHP against updated guidance to determine if any changes are warranted in
the LCCHP to ensure future protectiveness.

On December 23, 2009, Lake County passed a resolution that serves as the institutional control for the mine waste
piles in OU9. The resolution amended the Lake County Land Development Code Chapter 3.2 (Appendix K). The
Lake County Building and Land Use Department (LCBLUD) must provide building permit applicants within the
boundaries of the remaining mine waste piles in OU9 with a handout regarding best management practices for
managing potentially contaminated soils (including lead and arsenic). Applicants must sign a document attesting
that they received, read and understood the handout. No building permit is issued without an applicant's written
acknowledgement provided to LCBLUD. Additionally, written proof of approval from CDPHE is required before
LCBLUD will issue a building permit. Similarly, the city of Leadville passed an ordinance on May 7, 2013, that
acts as an institutional control for the six waste piles in OU9 that are located within city limits.

On May 16, 2013, the EPA signed a ROD Mod for the OU9 remedy that required institutional controls to: 1)
reduce or control human exposure to lead and arsenic; and 2) maintain the integrity of and prevent disturbances of
the engineered features or structures of the current or future remedies.

On April 4, 2002, the EPA partially deleted OU9 Subunits A and B, residential waste rock piles, and parks and
playgrounds from the NPL. The EPA partially deleted remaining portions of OU9 from the NPL on September
21, 2011. Environmental assessments and remediation performed by the OU9 Workgroup continue on a case-by-
case basis.

Systems Operations/Operation & Maintenance (O&M)

OU9 entered the O&M phase in 2010, when the EPA, Lake County and CDPHE approved the LCCHP Work
Plan. The LCCHP Phase 2 Work Plan was revised in October 2013. It serves as the O&M Plan for OU9.

The LCCHP Phase 2 has been designed to reduce overall lead-related risk to children in Leadville through
education of parents and blood-lead monitoring of children and, for people with elevated blood lead levels,
additional responses that investigate and address numerous sources. The potential sources of lead exposure that
are addressed include contaminated soil, house dust, interior and exterior paint, foreign candy and many other
items that contain lead. As part of the LCCHP, those tested whose blood-lead results are elevated are receive
educational materials and are monitored by Lake County Health to ensure their blood-lead levels decrease.

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XIII.2 OU9: PROGRESS SINCE PREVIOUS FYR

This section includes the protectiveness determinations and statements from the 2017 FYR Report (Table 17).
There were no recommendations identified from the 2017 FYR Report.

Table 17: Protectiveness Determinations/Statements from the 2017 FYR Report

()l #

PmU'iiiteiiess
lk'Urniin;i(ion

Pmlecliu'iiess M;iU-im-nl

Protective

The remedy at OU9 is protective of human health and the
environment. The remedy is functioning as intended by site
decision documents; the exposure assumptions, toxicity data,
trigger criteria and RAOs used at the time of the remedy
selection are still valid. No other information has come to light
that could call into question the protectiveness of the remedy.
Institutional controls are in place. O&M continues
successfully through the approval and implementation of the
LCCHP Phase 2 Work Plan.

XIII.3 OU9: FYR PROCESS

Data Review

Data from the Lake County Blood Lead Program's blood-lead testing database were reviewed and compared to
site RAOs. Table 18 lists the results.

Lake County Health administered 983 blood-lead tests to 583 individuals any age from 1/1/2017 to 12/31/2021.
Of the 583 individuals, a total of 438 individual children - age 72 months or less - were tested. Of these 438
children, 9 (2.1%) had blood-lead greater than 10 jj.g/dl. Of the 9, 3 (0.7%) had blood-leads greater than 15 jj.g/dl;
one child had recently moved to Lake County.

Some children - 72 months or less - were tested in multiple years. In the number above, 438, the children were
only counted one time during that five-year period. In the table below, individual children are counted once for
each calendar year.

Table 18: Blood Lead Testing Results, 2017 to 2021

# of Children

( oiktiiI ration

V ii of Children

( oiiceiili'iilion

V ii of Children

Tested

(iiViiKT lliiin

l esled > 10

(•iviiler lliiin

Tcsk'd > 15

Year

(11-72 iiionllis)

10 u»/dl.

MS/dl-

15 uji/dl.

20I"7

178

0.6

0.0

201S

149

2.7

0.7

20 iy

140

2.9

1.4

2020

0.0

2021

0.0

A\er;itii'

1.2

0.4

Table 18 shows that the annual average percentages of children ages 0 to 72 months with blood lead levels greater
than 10 (ig/dL and 15 (ig/dL are below the respective percentages of 5% and 1% set in the RAOs. Overall, the
average of the average percentages per year during the FYR period are 1.2% and 0.4%, respectively.

Remediations took place on several properties. Other elevated blood lead levels were resolved through education,
identification and/or further evaluations. The annual and monthly reports indicated that consumption of foreign
candy, lead-based paint, family member's occupation and other factors not related to lead in soil were contributing
factors to elevated blood lead levels. Additionally, remodeling of homes built before 1978 that have lead-based
paint appears to be linked to elevated blood lead levels in some children and adults.

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Site Inspection

The OU9 site inspection took place on June 16, 2022. Participants are listed in Section III of this FYR Report.
OU9 was observed and viewed during the site inspection by driving around the city, visiting several area parks
and observing a home that underwent lead remediation during this FYR period. Participants also observed the
Lake Fork community, where some lead removal had occurred historically. Photographs were taken of some of
the site features addressed under OU9 (Appendix G). An inspection checklist has been completed. It is available
in Appendix F.

XIII.4 OU9: TECHNICAL ASSESSMENT

QUESTION A: Is the remedy functioning as intended by the decision documents?

The site inspection and the review of documents, ARARs and risk assumptions indicate that the OU9
remedy is functioning as intended by OU9's 1999 ROD, 2009 ESD and 2013 minor modification to the ROD.

Performance standards were originally met in 2006. The LCCHP Phase 2 Work Plan is the long-term O&M Plan
for OU9. Per the 2017 through 2021 Blood Lead Testing Annual Reports, the O&M activities successfully
ensured that blood lead is monitored and that households are abated of lead contamination upon OU9 Work
Group approval. Institutional controls are in place through extension of the city of Leadville and Lake County
planning and zoning codes to protect engineered remedies in OU9. In addition, the LCCHP Phase 2 Work Plan
was accepted by Lake County. It serves as the institutional control for OU9, providing community outreach and
education on preventing lead exposures.

QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of the
remedy selection still valid?

The exposure assumptions and toxicity data used to develop range of plausible action levels for arsenic,
published in the BRA Part B, remain valid.

The Site's surface soil lead cleanup levels were established so that a child would have an estimated probability of
no more than 5% of exceeding a blood lead level of 10 (ig/dL. The EPA's scientific considerations to be used at
lead cleanups were outlined in the EPA's 1994 Revised Interim Soil Lead Guidance for CERCLA Sites and
Resource Conservation and Recovery Act (RCRA) Corrective Action Facilities (Office of Solid Waste and
Emergency Response (OSWER) Directive 9355.4-12) and the 1998 update to the 1994 guidance. Since issuing
the 1994 and 1998 guidance, the EPA's experience has demonstrated that lead-contaminated soil responses are
more effective when they employ a multi-pathway approach. However, since 1994 and 1998 when those
documents were issued, increasing evidence has shown that blood lead levels below 10 j^ig/dL may also have
negative health impacts. The EPA is currently evaluating its lead cleanup policy based on recent studies that
suggest adverse health effects are associated with blood levels less than 10 (ig/dL. The EPA will continue using
current lead policy until the Agency provides modified guidance for sites with lead contamination, after which
EPA Region 8 will evaluate the need for revisions to the LCCHP Phase 2 Work Plan. The EPA recognizes this
and uses the LCCHP Phase 2 approach which reflects a multi-pathway, community-based education and outreach
approach to identifying sources of lead and exposure pathways in Leadville.

QUESTION C : Has any other information come to light that could call into question the protectiveness of the
remedy?

No other information has come to light that could call into question the protectiveness of the remedy.

XIII.5 OU9: ISSUES/RECOMMENDATIONS

Issues/Recommendations

-------
()l (s) without Issucs/RocoiiiiiKMulitlioiis Iclcntilied in the l;M<:

OU9

XIII.6 OU9: PROTECTIVENESS STATEMENT

Operable Unit:
9

Protectiveness Statement(s)

Protectiveness Determination:
Protective

Protectiveness Statement: The remedy at OU9 is protective of human health and the environment. The
remedy is functioning as intended by site decision documents; the exposure assumptions, toxicity data,
trigger criteria and RAOs used at the time of the remedy selection are still valid. No other information
has come to light that could call into question the protectiveness of the remedy. Institutional controls
are in place. Testing, outreach, education and, if appropriate, remediation will continue successfully
through the approval and implementation of the LCCHP Phase 2 Work Plan.

XIV. OUIO: OREGON GULCH

OUIO is defined as the 500-year floodplain of Oregon Gulch, extending about one mile from its headwaters to its
confluence with Lower California Gulch. Oregon Gulch is about a half-mile south of Leadville and is
immediately west of OU1, the Yak Tunnel WTP and the surge pond (Figure D-12). The Oregon Gulch area is a
small V-shaped valley with water that flows in a northwesterly direction. The Oregon Gulch watershed drains
about 185 acres, including the 15.8-acre area of OUIO that includes the 14.2-acre Oregon Gulch Tailing
Impoundment and 1.6 acres of a portion of the 500-year floodplain. Oregon Gulch is an ephemeral tributary to
California Gulch. Before remediation, spring snow melt runoff and summer thunderstorms would result in
transport of tailings solids and contaminated surface water into California Gulch.

The Oregon Gulch Tailing Impoundment received tailings from the Newmont/Resurrection-ASARCO mill in
California Gulch from about 1942 through 1957. During removal activities in 1995 and 1996, about 28,000 cubic
yards of tailings and underlying soil from the CZL Tailing Impoundment on OU4 were relocated to the Oregon
Gulch Tailing Impoundment. An additional 550 cubic yards of sediment excavated from the culvert and
embankment in California Gulch within OU8 were also deposited on top of the Oregon Gulch Tailing
Impoundment in September 1996.

Stream sediment in the lower portion of Oregon Gulch has been contaminated with metals from tailings and
runoff complete from the Oregon Gulch Tailing Impoundment embankment. Release of tailings material was due
to erosion, that transported it and re-deposited it in the floodplain and stream channel of Oregon Gulch. Release of
soluble metals contained in runoff from the embankment and contained in a seep at the toe of the impoundment
contributed to the metal contamination of the sediments. The tailings impoundment has not been in operation
since 1957.

Land within OUIO is owned by Newmont/Resurrection Mining Company, with the exceptions of Lake County
Road 6 and two small parcels of federally-owned land managed by the Bureau of Land Management. Lake
County has zoned OUIO for industrial mining land uses.

XIV. 1 OUIO: RESPONSE ACTION SUMMARY

Basis for Taking Action

Based on the results of the sitewide RI/FS, the EPA determined that actual or threatened releases of hazardous
substances from sediments, soils, tailings and seep water on OUIO may present an imminent and substantial

-------
endangerment to public health, welfare or the environment if not addressed through remedial action. Table 19 lists
contaminated media in OUIO. Appendix B (Table B-14) provides a chronology of OUIO events.

Table 19: Contaminated Media, OUIO

Mcriiii

Coniiiiniiiiiiioii

Sediment

Sediments generally display elevated metal concentrations and high concentrations of pyrite.
Sediments collected at the mouth of Oregon Gulch contain elevated cadmium, iron, manganese
and zinc.

Mine tailings
and soil

Elevated lead and zinc concentrations were found throughout the depth of tailings profiles.
Arsenic and cadmium levels decreased as a function of tailings depth. Concentrations in
foundation soils underneath the tailings were significantly lower than in the tailings.

Seep water

A seep discharges from the base of the tailings embankment year-round. Water quality of the
seep discharge is poor, with low pH levels and elevated levels of dissolved metals.

Response Actions

Pursuant to the August 4, 1995, Action Memorandum, Resurrection Mining Company excavated about 3,500
cubic yards of sediment and soil from the channel and floodplain of Oregon Gulch and placed it on top of the
Oregon Gulch Tailing Impoundment. The work took place in 1995 and 1996. After sediment removal,
Resurrection Company constructed a channel capable of conveying a 100-year flood event and remaining stable
for a 500-year flood event. The area outside the channel was also stabilized and revegetated. Resurrection
Company also constructed a sedimentation pond in Oregon Gulch downstream of the toe of the tailings
impoundment to reduce sediment load in runoff from the tailings embankment.

A cultural resource inventory identified a historic trash dump in lower Oregon Gulch. The dump site begins near
the intersection of the gulch and County Road 6 and extends about 500 feet upstream. This area was
recommended for nomination to the National Register of Historic Places. The pre-ROD removal action and post-
ROD remedial actions were designed and constructed to avoid adverse impacts to this historically significant area.

The EPA issued the ROD for OUIO on August 8, 1997. The 1997 OUIO ROD established the following RAOs:

• Control airborne transport of tailings particles

• Control erosion of tailings materials and deposition in local water courses

• Control leaching and migration of metals from tailings into surface and groundwater

The selected remedy for OUIO consisted of the following components:

• Regrade the impoundment to provide positive drainage and to flatten embankments

• Install geosynthetic barrier to control infiltration, followed by a geocomposite drainage layer

• Install a soil cap with vegetation on top of impoundment

• Install a soil-and-gravel cap on the side slopes

• Construct lined diversion ditches to divert runoff from tailings to the covered tailings surface

• Install a groundwater cutoff trench to prevent groundwater infiltration

• Actively manage seeps by collecting seep and transporting (pumping) to the Yak Tunnel WTP

The EPA issued an ESD on July 29, 2013. It required institutional controls as a remedy component for OUIO. The
1997 OUIO ROD did not contain numeric cleanup standards but did specify removal and containment actions to
prevent tailings and stream sediments from contributing source contamination to surface water and groundwater
at the Site.

Status of Implementation

Resurrection completed removal actions in 1996. Resurrection implemented the selected remedy for the Oregon
Gulch Tailing Impoundment from July through October 1998. Activities included re-grading the impoundment

-------
surface to provide positive drainage, installing structural fill as needed over the impoundment surface, installing a
geosynthetic membrane over the structural fill to control infiltration, and placing an 18-inch-thick soil layer with a
vegetated cover over the membrane. A diversion ditch along the eastern side of the impoundment controls run-on
and runoff and an upgradient groundwater interception trench limits the infiltration of groundwater into the
tailings impoundment. A discharge drain system manages seep flow from the impoundment toe.

The EPA partially deleted OUIO from the NPL on April 16, 2001.

Lake County has zoned OUIO for industrial mining land uses. In addition, Newmont/Resurrection recorded
environmental covenants on its OUIO properties on July 31, 2012, and October 1, 2012. The covenants prohibit
residential use and restrict groundwater use.

Systems Operations/Operation & Maintenance (O&M)

Newmont/Resurrection has implemented O&M activities at OUIO since September 1999. O&M activities for the
Oregon Gulch Tailing Impoundment and related systems is required to assure that the remedy remains effective.
O&M includes inspection of the tailings impoundment cap and the seep collection and pumping system.

Newmont/Resurrection conducts inspections in accordance with the OU4, 8, 10, Operations and Maintenance
Plan, which is Appendix D to the 2008 Consent Decree approved on August 29, 2008. The EPA approved a minor
modification to the O&M Plan in 2018 to reduce the frequency of inspections at OU10, other than inspections of
the toe drain/interceptor trench, from biannually to annually. The toe drain/interceptor trench pump back system
continues to be inspected three times per week. Its findings are documented in the annual California Gulch
Superfund Site OU4, OU8 and OUIO inspection reports. These reports are available by contacting EPA Region 8.

The following areas in OUIO are inspected:

• The toe seep collection system, trench collection system and pump house

• The tailings impoundment surface and embankment

• East and South diversion ditches

• The drop channel

• The upper reconstructed channel

• The lower reconstructed channel

• Access road gates

Maintenance during the current FYR period has included repairs to piping, maintenance of the vegetated cover,
pump replacements, upgrades to electrical equipment, and maintenance of secured fencing and signage around the
pump house and the Oregon Gulch Tailing Impoundment.

XIV.2 OUIO: PROGRESS SINCE PREVIOUS FYR

This section includes the protectiveness determinations and statements from the 2017 FYR Report (Table 20).
There were no recommendations identified from the 2017 FYR Report.

Table 20: Protectiveness Determinations/Statements from the 2017 FYR Report

()l #

Pm(cc(i\eness
Ik-UTiiiiiiiilion

Pmlecliu'iK'ss Siiiiomonl

Protective

The remedy at OU 10 is protective of human health and the
environment. Source contamination has been consolidated and
contained to prevent migration of contaminants. Any seep or infiltrated
run-on or runoff is captured through trenches and pumped to the Yak
Tunnel WTP. All RAOs for OU 10 have been achieved and
Newmont/Resurrection Mining Company continues to implement O&M
activities. Institutional controls are in place as environmental covenants.

-------
XIV.3 OUIO: FYR PROCESS

Data Review

Resurrection Mining Company samples well OG1TMW3 annually for dissolved cadmium and zinc. This well is
located about 1,500 feet downstream of the toe of the impoundment embankment and is sampled to evaluate the
performance and effectiveness of the seep collection system. Table 1-4 presents the October 2020 sample results
compared to historical sample results, starting with samples collected by Colorado Mountain College in 2007 and
samples collected by other consulting firms since then. Over time, the concentrations show a continuing
decreasing trend in both dissolved zinc and the cadmium concentrations. The 2020 concentrations are much lower
than 2007 concentrations, with dissolved zinc detected at 129 milligrams per liter (mg/L) or 129,000 (ig/L in
2007, declining to 23.9 mg/L (23,900 (ig/L) in 2020. Similarly, the dissolved cadmium concentrations in 2007
were 0.142 mg/L (142 (ig/L). declining to 0.037 mg/L (37 (ig/L) in 2020. These results suggest that the seep
collection system is performing as intended.

Site Inspection

The OUIO site inspection took place on June 16, 2022. Participants did not observe this area due to time
constraints. This OU is inspected by Newmont/Resurrection. Features inspected include monitoring wells and
access controls. Mr. Runnells reported that a new pump house has been installed, along with new pumps. The
cover of Oregon Gulch tailings pile was reported to be well vegetated, and the drainage systems were
unobstructed and functioning. Groundwater and surface water that are diverted from the impoundment are
collected in the pump house. The water is then pumped to the surge pond to await treatment. An inspection
checklist has been completed (Appendix F). Inspection photographs were taken by the EPA's support contractor
and are included in Appendix G.

XIV.4 OUIO: TECHNICAL ASSESSMENT

QUESTION A: Is the remedy functioning as intended by the decision documents?

The site inspection and the review of documents, ARARs and risk assumptions indicate that the OUIO remedy
has been completed and is functioning as intended by site decision documents. Excavation of stream sediments
finished by 1996. Consolidation and stabilization of the Oregon Gulch Tailing Impoundment finished in 1998.
Newmont/Resurrection Mining Company continues to implement O&M activities for OUIO. All institutional
controls required by site decision documents are in place as are procedures to notify the EPA and CDPHE should
local governments approve a change in land use.

QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of the
remedy selection still valid?

There have been no changes to the ARARs identified in the ROD or since the previous FYR. No newly
promulgated standards have been identified that could call into question the protectiveness of the remedy as
implemented (see Appendix H for detail). The 1997 OUIO ROD did not establish numeric cleanup standards for
surface water or groundwater. The remedy for OU12 encompasses sitewide water quality.

All RAOs identified in the 1997 OUIO ROD have been achieved. These RAOs included controlling airborne
transport of tailings particles, controlling leaching and migration of metals from tailings into surface water and
groundwater, and controlling erosion tailings material into local water courses. The excavation of stream
sediments and consolidation of contaminated materials within the covered Oregon Gulch Tailing Impoundment
minimizes the potential for erosion of contaminated material into local waterways and for the leaching and
migration of contamination into surface water and groundwater. Diversion and interception trenches also capture
run-on, runoff and potential seep flow for treatment at the Yak Tunnel WTP. The geosynthetic membrane and
vegetated cover prevent airborne transport and erosion of tailings material. Land use at OUIO has not changed.
The exposure assumptions used in the development of the 1997 OUIO ROD remain valid.

-------
QUESTION C : Has any other information come to light that could call into question the protectiveness of the
remedy?

No additional information has come to light that would call into question the protectiveness of the remedy.

XIV.5 OUIO: ISSUES/RECOMMENDATIONS

Issues/Recommendations

()l (s) without Issues/Reconinieiuhlions Identified in (ho I YR:

OUIO

XIV.6 OUIO: PROTECTIVENESS STATEMENT

Operable Unit:
10

Protectiveness Statement(s)

Protectiveness Determination:
Protective

Protectiveness Statement: The remedy at OUIO is protective of human health and the environment.
Source contamination has been consolidated and contained to prevent migration of contaminants. Any
seep or infiltrated run-on or runoff is captured through trenches and pumped to the Yak Tunnel WTP.
All RAOs for OUIO have been achieved and Newmont/Resurrection Mining Company continues to
implement O&M activities. Institutional controls are in place as environmental covenants.

XV. OU11: ARKANSAS RIVER VALLEY FLOODPLAIN

OU11 extends from the confluence of the Arkansas River and California Gulch to an area of about 11 miles
downstream from the confluence on the Arkansas River (Figure D-13). It consists of lands impacted by transport
of metals and mining wastes via California Gulch and the Arkansas River.

Mine tailings transported downstream were deposited in many locations adjacent to the river. Contaminated water
and sediments were carried from the Arkansas River, via irrigation ditches, to meadows and fields both within and
outside the 500-year floodplain.

Agricultural land within OU11 is used for wildlife and livestock grazing. The Arkansas River floodplain is
currently used for grazing in some locations and recreation and fishing in other locations. Land-use modifications
are not expected in the near future. Colorado Parks and Wildlife (CPW) designated the Upper Arkansas River as a
Gold Medal fishery in January 2014.

OU 11 extends from the confluence of the Arkansas River and California Gulch to an area of about 11 miles
downstream from the confluence on the Arkansas River (Figure D-13). It consists of lands impacted by transport
of metals and mining wastes via California Gulch and the Arkansas River.

Mine tailings transported downstream was deposited in many locations adjacent to the river. Contaminated water
and sediments were carried from the Arkansas River via irrigation ditches to meadows and fields both within and
outside the 500-year floodplain.

-------
are not expected in the near future. Colorado Parks and Wildlife (CPW) designated the Upper Arkansas River as a
Gold Medal fishery in January 2014.

XV. 1 OU11: RESPONSE ACTION SUMMARY

Basis for Taking Action

Based on the results of OU11 screening-level baseline human health and ecological risk assessments completed in
2004 and 2003, respectively, and a supplemental mercury human health and ecological risk assessment completed
in 2007, the EPA identified metals in the irrigated meadows and riparian area soils as a potential health threat to
herbivores. Low pH conditions and metals result in phytotoxicity and poor plant demographics in the irrigated
meadows, fluvial mine wastes and riparian areas. Human health risks were determined to be below a level of
concern for current land uses. However, human health risks may be above a level of concern if areas of OU11 are
developed for residential uses in the future. Appendix B (Table B-15) provides a chronology of OU11 events.

Response Actions

The EPA's Removal Program stabilized eroding banks containing or protecting fluvial deposits in 1993 and 1994.
Beginning in 1996, the program identified and characterized fluvial deposits along nine miles of the Arkansas
River, evaluated alternatives for management of the wastes, and installed removal demonstration areas to allow
evaluation of the selected alternative.

The EPA signed the OU11 ROD on September 28, 2005. The RAOs established in the 2005 OU11 ROD were:

• Minimizing future human exposures to heavy metals as defined in the human health BRA

• Controlling leaching and migration of metals from contaminated materials into groundwater

• Reducing toxins in plants and improving plant demographics in the irrigated meadows, riparian areas and
fluvial mines wastes, as determined to be necessary

• Reducing exposures of wildlife and livestock to heavy metals in soil and vegetation at toxic
concentrations from direct exposure or bioaccumulation

• Minimizing erosion of fluvial mine wastes into the Arkansas River, as determined necessary to prevent
further harm to aquatic life

Components of the selected remedy in the 2005 OU11 ROD included:

• Treatment and maintenance of irrigated meadows areas. Treatment consisted of lime amendment or
lime/organic amendment, deep tilling and seeding.

• Maintenance of tailings deposits treated during prior response actions, as necessary. Maintenance will
include inspections and retreatment and/or repairs appropriate to enhance or reestablish vegetation.

• Treatment and maintenance of remaining tailings deposits. Treatment consisted of lime and organic
amendment, and deep tilling followed by seeding to physically stabilize the mine wastes through the
establishment of vegetation.

• No active revegetation of the (vegetated) riparian areas, although specific riparian areas may be
remediated if deemed appropriate during design.

• Institutional controls on irrigated meadows, tailings deposits and riparian areas. Institutional controls are
to be implemented to prevent changes in current land use unless the risks under the new land use are
demonstrated to be below a level of concern.

A Remedial Work Plan developed in 2007 specified treatments for irrigated meadows, fluvial deposits and
adjacent streambanks. Treatments included addition and mixing of lime, fertilizer and compost to mine waste and
soils, and seeding with land-use-appropriate species.

Cleanup levels were not established because the remedial action did not reduce contaminant concentrations in site
media. The 2007 Remedial Work Plan established performance criteria for treated areas to ensure that the
remedial action adequately addresses the risks posed by contamination in OU 11. Performance criteria included

-------
soil and vegetation criteria characteristics for irrigated meadows and fluvial deposits and stability characteristics
for remediated streambanks. Several vegetation monitoring events have occurred since the remedial action was
completed, and the success of the vegetation and the near-term ecological trajectory are well documented. The
performance criteria previously established in 2007 were revised in 2013 to account for a lower target organic
carbon addition rate for all areas. The impacts of this change were considered minor, and decision document was
deemed unnecessary.

Status of Implementation

The 2005 ROD called for the implementation of institutional controls on irrigated meadows, tailings deposits and
riparian areas. The EPA is currently working with CDPHE to determine an appropriate institutional control for
OU11.

The objectives of the institutional controls are to:

• Reduce or control human exposure to contaminants of concern

• Maintain the integrity of and prevent disturbances of the engineered features or structures of the current or
future remedies

• Prevent changes in current land use unless the risks under the new land use are demonstrated to be below
a level of concern using EPA risk assessment methods.

During 2008 and 2009, a remedial action by the EPA included in-situ treatment of 154 acres of irrigated meadows
and 18.5 acres of fluvial deposits, followed by seeding. Vulnerable stream banks next to the fluvial deposits were
reconstructed to protect the treated soils and allow establishment of vegetation. Forty acres of demonstration area
fluvial deposits that were treated with soil amendments between 1998 and 2000 and used to evaluate the
effectiveness of the selected alternative are considered part of the OU11 remedy. The EPA signed the Remedial
Action Completion Report for the bank stabilization on September 19, 2013.

In 2020 during the COVID pandemic, the EPA and CDPHE proposed an amendment to the Lake County Land
Development Code; the amendment is under review.

Systems Operations/Operation & Maintenance (O&M)

The treated areas were monitored from 2009 through 2012, in accordance with the Site's Monitoring and
Maintenance Plan. CPW restored fish habitat along the banks of the Arkansas River in 2014 and 2015. CPW
performed maintenance along the banks of the Arkansas to reestablish shoring rock that was relocated by high
water in 2015. The remedy is performing as expected. The results of monitoring will be used to determine when
and what maintenance is required, whether the remedy meets the RAOs, when the remediated areas are mature
and self-sustaining, and to facilitate the EPA's FYR process.

Maintenance work has included re-treatment of small parts of the demonstration areas, reseeding of bare and
sparse vegetation areas, repairs of constructed stream banks, stabilization of native stream banks impacted during
2011 extreme runoff conditions, and removal of construction roads.

The EPA determined that the remedy for OU11 was "Operational and Functional" on April 25, 2017, starting the
O&M phase. CDPHE conducts O&M activities through a Special-Account-funded grant.

XV.2 OU11: PROGRESS SINCE PREVIOUS FYR

This section includes the protectiveness determinations and statements from the 2017 FYR Report (Table 21) as
well as the recommendation from the 2017 FYR Report and the current status of the recommendation (Table 22).

Table 21: Protectiveness Determinations/Statements from the 2017 FYR Report

()l #

PmieclheiR'ss
lk'UTiiiin;ilioii

Prolecliu'iiess M;iU-im-nl

SllOl'l-lCl'lll h'OkVll\ 0

The iviiuxl} al Ul 11 ainvnlK piokvls human licallli and llic
environment. The streambanks have been stabilized to

-------
minimize erosion, exposure and chemical migration. For the
remedy to be protective over the long term, institutional
controls need to be implemented to ensure protectiveness

Table 22: Status of Recommendations from the 2017 FYR Report

Issiio

Kocoiiiiiioii(liili(ins

( II ITCH 1

Sliilus

( iinvnl liiiplcmcnliilion
S(;iliis Description

("11111 pkM ion

l);ilo til"
iippliciihlo)

Institutional
controls are a
component of the
selected remedy
but have not yet
been implemented.

Implement
institutional
controls.

Ongoing

ICs are being prepared that
would reduce exposure to lead in
the event land use were to
change to residential.

Not Applicable

XV.3 OU11: FYR PROCESS

Data Review

The remedial action for OU11 was completed in 2013. The remedy for OU12 is designed to achieve chemical-
specific, numerical performance standards for sitewide surface water and groundwater. Therefore, a summary of
the sitewide surface water and groundwater data are discussed in the Data Review section, Section XVI.3, for
OU12.

Site Inspection

The OU11 site inspection took place on June 16, 2022. Participants are listed in Section III of this FYR Report.
Photographs were taken of site features, including monitoring wells and access controls (Appendix G). The group
toured OU11 along the Arkansas River and nearby ranches. General conditions were noted in the site inspection
checklist (Appendix F). Overall Arkansas River floodplain conditions were observed to be functioning well
downgradient of the confluence with California Gulch. Flows were not impeded. Based on the OU11 inspection,
conditions discussed with site-visit personnel and monitoring and maintenance reports, the OU11 remedy was
implemented as designed.

XV.4 OU11: TECHNICAL ASSESSMENT

QUESTION A: Is the remedy functioning as intended by the decision documents?

The site inspection and the review of documents, ARARs and risk assumptions indicate that the remedy is
functioning as intended, in accordance with decision document requirements and design specifications. The EPA
stabilized the stream banks in 2013. CPW restored fish habitat along the banks of the Arkansas River in 2014 and
2015 due to high water events from snow melts. O&M responsibilities for OU11 transitioned to CDPHE in May
2017. Monitoring of surface water, sediment and biota is part of the OU12 sitewide remedy. Institutional controls
are under consideration.

QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of the
remedy selection still valid?

There have been no other changes in exposure assumptions to human health and the environment or toxicity
data that would call into question the protectiveness of the remedy. There are currently no proposed changes to
reuse plans for OU 11 that would affect the protectiveness of the remedy.

-------
QUESTION C : Has any other information come to light that could call into question the protectiveness of the
remedy?

No additional information has come to light that would call into question the protectiveness of the remedy.

XV.5 OU11: ISSUES/RECOMMENDATIONS

Issues/Recommendations

()l (s) without Issues/Recommendations Identified in the l-'Yk:

Not applicable

Issues itihI Recommendations Identified in the l-'Yk:

OU(s):

Issue Category: Institutional Controls

Issue: Institutional controls are a component of the selected remedy but have not
yet been implemented.

Recommendation: Implement institutional controls to reduce exposure to COCs,
protect engineered remedies and for future changes in land use.

Affect Current
Protectiveness

Affect Future
Protectiveness

Party Responsible

Oversight Party

Milestone Date

Yes

Other/Lake County

EPA/State

12/30/2024

XV.6 OU11: PROTECTIVENESS STATEMENT

Protectiveness Statement(s)

Operable Unit: Protectiveness Determination:

11 Short-term Protective

Protectiveness Statement: The remedy at OU11 currently protects human health and the environment. The
streambanks have been stabilized to minimize erosion, exposure and chemical migration. For the remedy to
be protective over the long term, institutional controls should be implemented to reduce exposure to COCs,
protect engineered remedies and for future changes in land use in the event the land use were to change to
residential.

XVI. OU12: SITE WIDE WATER QUALITY

The EPA listed the Site on the NPL on September 8, 1983. At that time, the EPA divided the Site into 11
geographic, media-driven OUs. An additional OU - OU12 - was included to address sitewide surface water and
groundwater and to measure the improvements on downgradient water quality as source areas are remediated and
stabilized at the other 11 OUs. OU12 encompasses the entire 18-square-mile Site. Included in OU12 are the cities
of Leadville and Stringtown, portions of the Upper Arkansas River Valley below the confluence of California
Gulch with the Arkansas River as well as California Gulch, Stray Horse Gulch, portions of Evans Gulch, and
minor tributaries to these drainages. An additional geographic constraint was imposed on OU12 groundwater.
OU12 groundwater only includes the shallow alluvial aquifer, not to exceed a depth of 250 feet or contact with
bedrock, whichever is the lesser depth below the ground surface.

-------
Residents of Leadville and nearby areas of Lake County are served by Parkville Water District for their drinking
water. Areas not served by Parkville use well water. Testing has revealed no drinking water wells exceeding
MCLs since the mid-1980s.

XVI. 1 OU12: RESPONSE ACTION SUMMARY

Basis for Taking Action

Human Health Risks

In the mid-1990s, human health risk assessments by the EPA concluded that contaminants in sitewide surface
water and groundwater may pose unacceptable human health risks in the future, should people consume
contaminated site water. Sources of contamination of these media include mine wastes that generate ARD. In the
1990s, the EPA considered mine wastes at Upper California Gulch (OU4), Stray Horse Gulch (OU6), the Apache
Tailing Impoundments (OU7) and Oregon Gulch (OUIO) to constitute the significant sources for ARD at the Site.
Since the 1990s, actions have been taken to address these source areas.

Ecological Risk

As described in the 1995 BRA and the 2004 OU12 ecological risk assessment of contaminants in the Upper
Arkansas River, the COCs for trout and macroinvertebrates are zinc and cadmium. Because brown trout are the
predominant species in the river, the EPA has focused primary attention on this species. In 2004, the EPA
concluded that survival of brown trout fry was likely decreased by historical concentrations of zinc and cadmium
that occurred below California Gulch during spring snow melt. This, in turn, was a likely contributing factor to
lower-than-expected fish density below California Gulch (compared to above). In recent years, the level of
predicted risk to fish has been decreasing and the observed number of fish has been increasing. This is consistent
with the completion of remedial activities at mining waste source areas that began in the 1990s. Long-term
monitoring of OU12 will determine whether this apparent trend toward recovery is a consequence of decreased
site releases.

The EPA also concluded that the survival and reproduction of some species of benthic macroinvertebrates are
likely to be decreased by concentrations of zinc and cadmium that often occur below California Gulch during
spring snow melt. This in turn leads to a tendency for reduced numbers of sensitive taxa (mainly mayflies) in the
river below the confluence with California Gulch compared to above. However, the overall density and diversity
of the benthic community does not appear to be substantially impaired. It seems likely that availability of benthic
prey items is not limiting fish.

Risk to herbivores and plants along the Arkansas River, although caused by historical irrigation by sitewide
surface water, were remediated under the remedy for OU11. None of the risk assessments by the EPA to date
provide an assessment of risks to terrestrial receptors from ingestion of potentially contaminated aquatic prey
items. This is not considered to be a major omission or source of uncertainty for the following reasons. None of
the metals of concern at the Site tend to strongly accumulate in the tissues of aquatic species such as fish or
aquatic invertebrates. Ecological risk assessments at other mining sites indicate that exposure of terrestrial
receptors is usually most strongly determined by ingestion of contaminated soils or sediments rather than
ingestion of aquatic prey items. Table 23 presents COCs by medium for OU12. Although there are a wide range
of COCs, zinc and cadmium are considered reasonable indicator parameters with respect to the OU12
groundwater and OU12 surface water, as well as to human health and the environment in the vicinity of OU12.

Table 23: Contaminated Media, OU12

Medium

Popuhilion

COC

Surface water

Human health

Cadmium
Copper
Lead
Zinc

Ecologicaf receptors

Cadmium
Zinc

-------
Medium

Popuhilion

COC

Groundwater

Human health

Arsenic
Cadmium

Lead
Manganese
Zinc

Appendix B (Table B-16) provides a chronology of OU12 events.

Response Actions

Investigations began in the mid-1980s and continued through 2012. A complete list of investigative reports
relevant to OU12 can be found in the OU12 RI Report and in the Administrative Record for OU12. As of fall
2003, response actions designed to reduced metal loading to surface and groundwater have occurred in all areas
identified as major sources (waste rock piles, fluvial and mill tailings, and WTPs for the Yak Tunnel and LMDT).
These response actions were conducted in individual OUs under RODs or action memoranda. These actions
resulted in improvements to surface water and groundwater quality within the individual OUs, and also resulted in
improvements to sitewide surface and groundwater downgradient of the individual OUs. The EPA selected the
OU12 remedy in the 2009 OU12 ROD, which included institutional controls and long-term monitoring of surface
water and groundwater. In addition, the EPA implemented a technical impracticability (TI) waiver for shallow
groundwater (e.g., waiving the maximum contaminant levels [MCLs]).

The RAOs for OU12, as listed in the 2009 ROD, include:

•	Prevent unacceptable exposure of aquatic organisms in the Arkansas River to COCs

•	Prevent unacceptable human exposure to COCs in surface and groundwater

The OU12 remedy includes:

•	No action (no additional active remediation) for sitewide surface or groundwater

•	Institutional controls to restrict the use of surface and groundwater. The controls will minimize the
likelihood of adverse human health effects from the consumption of contaminated site water. Because
Arkansas River water meets drinking water standards, the institutional controls will not apply to the
Arkansas River.

•	Collection and review of long-term monitoring data

•	A TI waiver of MCLs for lead and cadmium in the shallow alluvial aquifer down to a depth of 50 feet in
California Gulch, Oregon Gulch, Stray Horse Gulch and a small area of the Arkansas Valley floodplain
near the confluence of California Gulch (Figure H-l)

Table 24 provides a summary of the cleanup goals for surface water from the ROD, which correspond to
Colorado's 2009 Water Quality Standards for segments of the Upper Arkansas River).

Table 24: Surface Water COC Cleanup Goals

COC

W;ikT Qu;ili(\
Siiindiird

200') ()l 12 KOI) ( Iciiiiup (.(nils lor \ik;nis;is Ri\cr Socmen Is
2h iind 2c (iiii/l.)'1

Cadmium
Dissolved

June to March

Acule. 1.13oo~J-|linlianliios>s>,) \ 0.041S3SJ \ e

Chronic: 1.101672-[ln(hardness) x 0.041838] x e07998[ln(hardness)]"3 1725)

Seasonal Modification
(April to May)

1.34 (ng/L)

Zinc

Dissolved

June to March

AciltC 0 978 X g0-8537[ln(hardness)]+2.2178

Chronic' 0 986 X e°-8537[Mhardness)]+2.0489

Seasonal Modification
(April to May)

649 (ng/L)

60

-------
(¦<><¦

Wilier Qu;ili(\
Siiindiird

200') ()l 12 KOI) ( k-;iiui|> (>o:ils lor Arkiinsiis Ri\cr Segments
2h iind 2c (.nii/l -

Xotes:

;i Criteria listed in 2009 OU12 ROD, pages DS-48 and DS-49.

Status of Implementation

Remedial action at OU12 is anticipated to be completed in fall 2022. The EPA and CDPHE are currently
conducting the long-term monitoring component of the remedy. This effort includes annual sampling events in
accordance with the 2018 California Gulch Superfund Site Final Field Sampling Plan. Long-term monitoring
began following the EPA's approval of the April 2015 Remedial Design Report. The report summarizes the
monitoring plan for sampling surface water, groundwater and aquatic organisms; it was implemented by
modifying the previous sampling plan. As stated in the 2009 ROD, the EPA and CDPHE expect that long-term
monitoring will show that surface and groundwater quality continue to improve as source areas across the other
11 OUs continue to be remediated and stabilized.

Despite the State Water Quality Board's removal of the seasonal modification to water quality standards for
cadmium and zinc in segments 2b and 2c of the Arkansas in 2014, the 2022 water quality standards for these
metals and segments in the Arkansas River are being met (see additional detail in the Data Review section). The
EPA is working to finalize remaining institutional controls for OU12.

The OU12 2009 ROD required the implementation of institutional controls as environmental covenants on
specific parcels, a Lake County Ordinance, Parkville Water District Rules and Regulations, or a Colorado State
Engineer notice. Since the 2009 ROD, OU12 institutional controls have been implemented as environmental
covenants on Newmont/Resurrection land parcels and by Parkville Water District rules.

The environmental covenants on Newmont/Resurrection properties states:

No use of untreated groundwater from wells located on the property for drinking, domestic, or
agricultural purposes shall be allowed. This covenant does not restrict the use of groundwater that is
treated to meet the applicable State water quality standards for the beneficial use to which the water is
being applied. Treatment must meet any applicable State standards that are in place at the time of use.

Parkville Water Rules and Regulations restricts private wells in the Parkville Water District which serves the city
of Leadville, Stringtown, and adjacent areas. More information on this institutional control can be found on page
Appendix K-ll.

More institutional controls are being considered to restrict groundwater and surface water use within OU12. In
2020, the EPA and CDPHE proposed an amendment of the Lake County Land Development Code with additional
measures designed to prevent unacceptable exposures to contaminated waters. The amendment is under review.

Systems Operations/Operation & Maintenance (O&M)

The April 2015 Remedial Design Report contains the long-term monitoring plan for sampling surface water,
groundwater and aquatic organisms. This plan also serves as the O&M Plan for OU12.

XVL2 OU12: PROGRESS SINCE PREVIOUS FYR

The effectiveness of the OU12 remedy was not evaluated as part of the 2017 FYR. There were no issues and
recommendations identified in the 2017 FYR Report for OU12. The remedial design was completed on April 29,
2015. The remedy is currently in remedial action. Its completion is anticipated in September 2022.

This section includes the protectiveness determinations and statements from the 2017 FYR Report (Table 25).

-------
Table 25: Protectiveness Determinations/Statements from the 2017 FYR Report

()l #

PmieclheiR'ss
l)cUTinin;ilion

Pmlecliu'iiess Sliiiomonl

Will be Protective

The remedy at OU12 is expected to be protective of human
health and the environment upon completion. Surface water
and groundwater monitoring is occurring at the Site and the
data show that zinc and cadmium concentrations in surface
water met Colorado Water Quality standards at the point of
compliance. A technical impracticability waiver for
groundwater contamination was enacted by the 2009
ROD. For the OU 12 remedy to be protective over the long
term, institutional controls need to be implemented.

XVL3 OU12: FYR PROCESS

Data Review

OU12 addresses sitewide surface water and groundwater to measure the improvements on downgradient water
quality as source areas are remediated and stabilized at the other OUs. At the time of the completion of the 2003
OU12 RI/FS, response actions were completed that reduced metal loading to both surface and groundwater in all
the major source areas, including:

• Water treatment (OU1 and OU6).

• Consolidated, relocated and/or covered mine wastes (OU2, OU4, OU5, OU6, OU7, OU8, OU9 and
OU10).

• Stormwater diversions (OU4, OU5, OU6, OU7, OU8 and OU10).

• In-situ treatment of soils/mine waste (OU 11).

The Yak Tunnel was identified as contributing 80% of the metal load to Lower California Gulch. The other
contributors were either large tailings piles or impoundments or sulfidic waste rock piles that generated millions
of gallons of ARD during storm or snow-melt events each year.

The EPA, CDPHE and Tetra Tech collectively developed the 2015 Remedial Design Report, which includes a
surface water monitoring program, a groundwater monitoring program and an aquatic life monitoring program in
the California Gulch and Upper Arkansas River watersheds. Figure 1-2 shows the OU12 groundwater and surface
water monitoring locations. The first annual monitoring event occurred in 2015. Data are reviewed as collected on
an ongoing basis by the EPA and CDPHE. The data included for this FYR period are the annual monitoring
reports for data collected in 2017, 2018, 2019 and 2021. Due to the COVID-19 public health emergency, annual
monitoring was not completed in 2020. This data review focuses on the most current data relative to historical
trends to understand whether downstream concentrations are improving as source areas are addressed.

Surface Water Monitoring

Surface water originating on site flows down California Gulch and into the Arkansas River. All tributaries
contributing flow to California Gulch are ephemeral, flowing only in response to spring snowmelt and summer
precipitation events. Prior to mining, California Gulch likely was an ephemeral to intermittent stream; however,
discharges from the Yak Tunnel WTP and the Leadville Sanitation District WTP now result in nearly continuous
flows in California Gulch from the Yak Tunnel WTP outfall to the confluence with the Arkansas River. Routine
surface water samples are collected along California Gulch, Stray Horse Gulch/Starr Ditch, and the Arkansas
River. These samples are analyzed for a number of metals including those found in Table 25. The data review
focuses on zinc and cadmium, as specified in the 2009 OU12 ROD. The single point of compliance (POC) for
evaluating long-term remedy effectiveness of overall site remedies is at a location in the Arkansas River between
the confluences with California Gulch and the Lake Fork of the Arkansas River. The POC is represented by AR-
3A, as this location is located about a half mile downstream of California Gulch and is located within Segment 2b
of the Arkansas River. The 2009 OU12 ROD also specified that long-term monitoring include a reference

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location, AR-1, on the Arkansas River upstream of the Site. This location is about a quarter mile downstream of
Tennessee Creek, and is located within Segment 2a of the Arkansas River, upstream of the Site.

Table 26 summarizes the long-term monitoring program data and objectives.

Table 26: Long-term Monitoring Requirements and Objectives

Monitoring

Ohjeelite

Surface water sampling in
Lower California Gulch and the
Arkansas River

•	Evaluate hydrologic and water quality data in lower California Gulch and assess
loading of COCs from California Gulch to Arkansas River Segment 2b

•	Evaluate seasonal and annual trends in the concentrations and loading of COCs in the
Arkansas River

•	Evaluate water quality data for the upper Arkansas River to understand how changes
in COC concentrations potentially influence the aquatic community upstream and
downstream of California Gulch

Groundwater monitoring

• Evaluate how changes in hydrologic conditions impact COC concentrations

Aquatic life monitoring

• Evaluate results of fish3 population and macroinvertebrate monitoring in the upper
Arkansas River to document how the aquatic community downstream of California
Gulch is influenced by the Site

Notes:

a. The fish monitoring data were not available for inclusion due to the COVID pandemic in the 2021 Annual Surface

Water, Groundwater, and Biological Monitoring Report.

Source: 2021 Annual Surface Water, Groundwater, and Biological Monitoring Report.

Lower California Gulch

Routine monitoring in California Gulch Station CG-6 began in April and continued through August 2021. Station
CG-6 is located in Lower California Gulch just before the Arkansas River confluence, to represent the overall
water quality trends for California Gulch and its tributaries. Dissolved zinc and cadmium concentrations and
loading measured at Station CG-6 during 2021 are illustrated in Figure I-10 and 1-11, respectively. As shown in
these figures, the dissolved zinc and cadmium concentrations and loads peaked in late April. The concentrations
and loads of both metals decreased following the freshet, with zinc trends declining faster than cadmium.

Arkansas River

The attainment of cadmium and zinc aquatic life standards in the Arkansas River at Stations AR-1 and AR-3A
during the most current monitoring events (2021) based on compliance with the current Colorado Water Quality
Standards (WQS) is summarized in Table 27 and discussed below. The Site's annual OU12 surface water,
groundwater, fluvial sediment and biological monitoring reports provide more information. The loads and
concentrations of the dissolved forms of zinc and cadmium at Stations AR-1 and AR-3A in 2019 and 2021 are
illustrated in Figures 1-3 through 1-9. The meeting of compliance standards for zinc and cadmium in 2021 are
illustrated in Figures 1-11 and 1-12.

Table 27: Metals Concentration and CO WQS Goals in the Arkansas River, 2021

Siiniplin^
Million/ CO
\\ OS Segment ol
I pperArk

Number of
Dsijs Samples
collected

Number of l);i\s
Ssimples Mel CO
WQS Chrome
Sliindiirds

Comments





(iidiiiiuin

Vi lie



AR-1/ 2a

12

10

7

Located iiDstrcam of California Gulch.

AR-2/ 2b

1

1

0

Located iiDstrcam of California Gulch

AR-3A/2b

12

12

12

Point of Compliance located a half mile
downstream of California Gulch

AR-3B/2b

1

1

1

Arkansas River just upstream of the
confluence with Lake Fork

63

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AR-4/2c

Arkansas River @ 0.5 miles downstream
of confluence with Lake Fork

AR-5/2c

Arkansas River upstream of confluence
with Empire Gulch and @0.25 miles
downstream of Hwy 24 Bridge

Source: 2021 OU12 Annual Report, chart 3-6.

The results indicate that Colorado water quality standards for cadmium and zinc at the POC location AR-3A are
being met. Because the hardness of the water effects the amount of dissolved cadmium and zinc in the water,
Colorado WQS use a calculated standard that accounts for the hardness. The standards are calculated, using the
applicable formula, for each sample using the measured hardness at the time of sampling. For cadmium, the
meeting of compliance standards for AR-l/WQS Segment 2a uses the Table Value Standard, while the sampling
results for AR-3A/WQS Segment 2b is compared to the hardness calculated standard that uses the site-specific
equation (SSE) formula. The difference in formulas used to calculate the CO WQS compliance standards and the
differences in hardness and flow rates explain the variances between AR-l/Segment 2a and AR-3A/Segment 2b's
compliance rates.

Because ARARs are frozen at the time of the ROD, the compliance standards were recalculated using the
formulas from 2009 for chronic cadmium and chronic zinc in AR-1 (before the POC) and at AR-3A (the POC).
The results for AR-3A were similar to the results compared to the CO WQS analysis. The results for AR-1
showed a higher compliance rate to the 2009 ROD's hardness calculated standards than the compliance rate
compared to the ever-changing CO WQS.

More specifically, when the sampling results since the 2017 FYR for AR-3A are compared to the ROD chronic
standards, only four samples of the 131 AR-3A samples exceeded the chronic standard for cadmium (one sample
is a duplicate sample), and one of these samples also exceeded the acute cadmium value. Similarly, only two of
131 samples exceeded the chronic standard for zinc, one of which also slightly exceeded the acute value. All of
the exceedances occurred in 2019, an extremely high-water year. However, most of the exceedances were only
slightly above the ROD standards adjusted for hardness (Table 28).

Table 28: Cadmium and Zinc Exceedances Compared to ROD at POC Location AR-3A

Siimpk*

I)issnl\i'(l

KOI) ll;ii(liK'ss-l);isc(l

Chronic Se;ison;il

Diilo

( <>iici'iilr;ilioii

Chronic Siiindiinl

Acule Siiindiinl

Siiindiinl ( April-

(.Inno lo Miii'ch)

(.Inno lo Miircli)

M;i\)

( ;i«l in in in

5/21/2019

0.00136

0.00134

5/30/2019

0.00135

0.00134

5/30/2019

0.00140

0.00134

6/13/2019

0.00089

0.00079

0.00080

/.inc

6/4/2019

0.250

0.230

0.271

6/13/2019

0.213

0.186

0.218

Notes:

- = sample date not in this time frame.

All values presented in mg/L.

Reviewing the AR-1 data compared to the 2009 ROD calculated standards, one exceedance for chronic cadmium
(5/5/2017 3.58 jj.g/1 hardness 61 std 1.34 jj.g/1) out of 89 samples was found; no exceedances for chronic zinc.

According to the 2009 OU12 ROD, water quality would be considered to have attained the ROD standards if 85%
of the measurements are equal to or less than the chemical-specific standards. Overall, 97% of the of the cadmium
values and 98% of the zinc values attained the surface water standards established in the 2009 OU12 ROD. Since
the 2009 ROD, the CO WQS have been revised several times for cadmium and zinc in Arkansas River segments
2a, 2b and 2c. The 2009 ROD standards were compared to the most current state standards and the current state

-------
standards are the same as the ROD standards, with one exception. The acute hardness-dependent standard for
cadmium is currently slightly higher (less stringent) than the ROD standard (Appendix H).

Groundwater

The 2009 TI waiver waived the MCLs for cadmium and lead at specific portions of the OU12 shallow alluvial
groundwater, as shown on the map (Figure H-l) of the TI waiver boundary. Groundwater samples are collected
from 29 alluvial groundwater wells on annual basis to monitor groundwater quality in areas along California
Gulch and the Arkansas River where interaction between groundwater and surface water is most likely to occur.
In addition, some of these wells are located closest to engineered remedies (e.g., the Malta, Apache and CZL
Tailing Impoundment). Table 29 lists constituents exceeding a groundwater human health standard and the
number of wells with exceedances in 2021.

Table 29: Summary of Samples Exceeding Groundwater Human Health Standards in 2021

(¦<>(¦

Number of I'.xcml.iiicos

Arsenic

Cadmium

Lead

Manganese

Zinc

Source: 2021 OU12 Draft Annual Report, Chart 3-11.

The highest concentrations observed in California Gulch groundwater monitoring network wells in 2021 are
compared to human health standards in Table 30.

Table 30: Maximum 2021 Groundwater Concentrations Compared to Human Health Standards

((>(

Siiindiird

Miixiiiuiin Value

imii/i.)

Well

Eicporlcri ( (inconlriilion img/l.)

Arsenic

0.01

AP1TMW23

0.0188

Cadmium

0.005

AP1TMW23

0.106

Lead

0.015

AP1TMW16S

0.483

Manganese*

0.05

AP1TMW23

158.0

Zinc*

AP1TMW23

83.2

Notes:

* Secondary drinking water standard contaminant of concern.

Source: 2021 OU12 Draft Annual Report, Chart 3-12.

In 2021, wells AP1TMW23 and AP1TMW16S exhibited the highest exceedances; these wells are monitoring the
Apache Tailings Impoundment. Previously in 2019, the highest exceedances were observed in the area of the
confluence of California Gulch and Arkansas River and downgradient of the CZL Tailings Impoundment.

In general, zinc concentrations observed in select site monitoring wells have decreased by an order of magnitude
since 2000, while zinc concentrations in other wells have not changed. Results show that the number of
groundwater standard exceedances in 2021 indicate that source areas in California Gulch and Stray Horse Gulch
continue to negatively impact groundwater quality.

Aquatic Life

CSU collected benthic macroinvertebrate samples at several Arkansas River locations and in California Gulch
near the mouth in 2021, including the OU12 reference location (AR-1) and point of compliance (AR-3A). The
results of the 2021 CSU macroinvertebrate sampling are summarized in Table 1-5. The 2021 results are
summarized below:

o Macroinvertebrates were more abundant (# individuals) but less diverse (# taxa) at AR-1 and AR-3A
than in the previous year's fall sampling

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o The percentage of Heptageniidae (a metal-sensitive family of mayflies) was higher at AR-1 than at
AR-3A

Comparison of fall 2021 macroinvertebrate metrics in Arkansas River to long-term averages suggest an increase
in abundance upstream of California Gulch (AR-1) and downstream (AR-3A), but a decrease in diversity at both
locations. The percentage of Heptageniidae present at both locations increased at AR-1 and decreased at AR-3A.

Site Inspection

The OU12 site inspection took place on June 16, 2022. Participants are listed in Section III of this FYR Report.
Photographs were taken of site features, including monitoring wells and access controls (Appendix G). An
inspection checklist has been completed. It is available in Appendix F. Monitoring locations in the Arkansas
River and California Gulch were observed. The surface water features were unobstructed and wells appeared to be
in good condition and were secured with locks.

XVI.4 OU12: TECHNICAL ASSESSMENT

QUESTION A: Is the remedy functioning as intended by the decision documents?

The OU12 remedy is fully implemented. The remedy for OU12 includes ongoing long-term monitoring and
institutional controls. An IC to address groundwater and surface water restrictions in OU12, including the TI
waiver area, is under consideration. The EPA and the State continue to work towards establishing additional
institutional controls. Routine surface water and groundwater monitoring are ongoing at the Site. According to the
2009 OU12 ROD, water quality would be considered to have attained the ROD standards if 85% of the
measurements are equal to or less than the chemical-specific standards. Overall, 97% of the of the cadmium
values and 98% of the zinc values attained the surface water standards established in the 2009 OU12 ROD at the
POC.

QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of the
remedy selection still valid?

The exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of remedy selection are
still valid.

The 2009 TI waiver waived the MCLs for metals, specifically cadmium and lead, at specific portions of the OU12
shallow groundwater as depicted on the map of the TI waiver boundary found in the 2009 OU12 ROD. The
selected remedy complies with all action-specific ARARs. Since the selected remedy involves no construction,
location-specific ARARs do not apply. Colorado removed the seasonal modification to the water quality standards
(WQS) for Segments 2b and 2c in 2014. Because these new WQS standards are being met, no newly promulgated
standards have been identified that could call into question the protectiveness of the chosen remedy. The state
surface water quality standards have been revised several times for cadmium and zinc in Arkansas River segments
2a, 2b and 2c. The 2009 ROD standards were compared to the most current state WQS standards and the current
state standards are the same or less stringent as the ROD standards, with one instance where the acute hardness-
dependent standard for cadmium is currently slightly higher (less stringent) than the ROD standard (Appendix H).

QUESTION C : Has any other information come to light that could call into question the protectiveness of the
remedy?

No additional information has come to light that would call into question the protectiveness of the remedy.

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XVL5 OU12: ISSUES/RECOMMENDATIONS

Issues/Recommendations

()l (s) without Issucs/Rccommcndations Iclcntilied in the l-'Yk:

None

OU(s):

Issue Category: Institutional Controls

12

Issue: Additional ICs to restrict groundwater and surface water uses have not
been implemented as required by the OU12 ROD.



Recommendation: Implement additional institutional controls.

Affect Current
Protectiveness

Affect Future
Protectiveness

Party
Responsible

Oversight Party

Milestone Date

No

Yes

Other/Lake
County

EPA/State

12/30/2024

XVI.6 OU12: PROTECTIVENESS STATEMENT

Protectiveness Statement(s)

Operable Unit:	Protectiveness Determination:

12	Short-term Protective

Protectiveness Statement: The remedy at OU12 is protective of human health and the environment in
the short-term. Surface water and groundwater monitoring is occurring at the Site and the data show
that zinc and cadmium concentrations in surface water met Colorado Water Quality standards at the
POC. A TI waiver for groundwater contamination was enacted by the 2009 ROD. For the OU12
remedy to be protective over the long term, the EPA should complete implementation of the additional
institutional controls.

XVII. NEXT REVIEW

The next FYR Report for the California Gulch Superfund site is required five years from the completion date of
this review.

67

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APPENDIX A - REFERENCE LIST

2008-2009 Monitoring and Maintenance Report, Operable Unit 11. California Gulch Superfund Site, Leadville,
Colorado. Prepared by URS Operating Services, Inc. for EPA Region 8. June 20, 2011.

2015 Surface Water, Groundwater, Fluvial Sediment and Biological Monitoring Report, Operable Unit 12.
California Gulch Superfund Site, Leadville, Colorado. Prepared for Colorado Department of Public Health and
Environment Hazardous Materials and Waste Management Division by Tetra Tech. February 2017.

2016 Surface Water, Groundwater and Biological Monitoring Report, Operable Unit 12. California Gulch
Superfund Site, Leadville, Colorado. Prepared for Colorado Department of Public Health and Environment
Hazardous Materials and Waste Management Division by Tetra Tech. June 2017.

2017 Surface Water, Groundwater and Biological Monitoring Report, Operable Unit 12. California Gulch
Superfund Site, Leadville, Colorado. Prepared for Colorado Department of Public Health and Environment
Hazardous Materials and Waste Management Division by Tetra Tech. June 2018.

2018 Surface Water, Groundwater and Biological Monitoring Report, Operable Unit 12. California Gulch
Superfund Site, Leadville, Colorado. Prepared for Colorado Department of Public Health and Environment
Hazardous Materials and Waste Management Division by Tetra Tech. June 2019.

2019 Surface Water, Groundwater and Biological Monitoring Report, Operable Unit 12. California Gulch
Superfund Site, Leadville, Colorado. Prepared for Colorado Department of Public Health and Environment
Hazardous Materials and Waste Management Division by Tetra Tech. July 2020.

2021 Operations and Maintenance Facility Inspection Operable Units 2, 5, and 7. California Gulch Superfund
Site, Leadville, Colorado. Prepared for Colorado Department of Public Health and Environment Hazardous
Materials and Waste Management Division by Tetra Tech. February 2022.

Action Memorandum OU6. Removal action for the Stray Horse Gulch OU6 Site, Leadville, CO. November 2014.

Action Memorandum OU6. Removal action for the Stray Horse Gulch OU6 Site, Leadville, CO. June 2016.

Action Memorandum OU9. Removal action for Three Residential Properties, Leadville, CO. September 2016.

Action Memorandum OU6/12. Removal action forthe Stray Horse Gulch OU6/12 Site, Leadville, CO. June 2016.

Amending the Lake County Land Development Code and Adopting Regulations Concerning Institutional
Controls for Operable Units Within the California Gulch Superfund Site. County of Lake and State of Colorado.
February 2009.

Annual Blood-Lead Program Report - 2017 - 2021 Memorandum. Lake County Colorado. Prepared by the
Environmental Protection Agency. August 2022.

Baseline Human Health Risk Assessment, California Gulch Superfund Site, Leadville, Colorado, Part A, Risks to
Residents from Lead. EPA Region 8. June 2, 1996.

Baseline Human Health Risk Assessment, California Gulch Superfund Site, Leadville, Colorado, Part B, Risks to
Residents from Contaminants other than Lead. EPA Region 8. January 2, 1996.

Baseline Human Health Risk Assessment, California Gulch Superfund Site, Part C, Evaluation of Worker
Scenario. Roy F. Weston, Inc. April 1995.

A-l

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Best Management Practices for Managing Lead, Arsenic and Cadmium Containing Soils in Lake County,
Colorado. Lake County Building and Land Use Department. February 28, 2022.

California Gulch Superfund Site Operations and Maintenance Plan Operable Units 2, 5 and 7. Prepared by
CDPHE. October 2016.

CERCLA Information System Site Information accessed from website

https://cumulis.epa.gov/supercpad/cursites/csitinfo.cfm?id=0801478. Accessed October 21, 2016.

City ofLeadville, Colorado Ordinance 3, Series 2013. Ordinance to Amend the Leadville Municipal Code and
Adopting Regulations Concerning Institutional Controls for Portions of Operable Units 3, 5, 6,7, 8 and 9 within
the California Gulch Superfund Site located within the City. May 2013.

Completion Report, Yak Tunnel Monitoring Wells, California Gulch Superfund Site, Leadville, Colorado.
Woodward-Clyde Consultants. February 1992.

Consent Decree. California Gulch Superfund Site, Leadville, Colorado. United States District Court. May 1994.

Construction Completion Report, Apache Tailing Impoundments, Operable Unit 7, California Gulch Superfund
Site, Leadville, Colorado. MFG, Inc. December 2003.

Construction Completion Report, California Gulch Operable Unit 11, Remedial Action. Frontier Environmental
Services, Inc. January 2011.

Construction Completion Report, Yak Tunnel Operable Unit, California Gulch Superfund Site, Leadville,
Colorado. Res-ASARCO Joint Venture. February 1993.

Direct Final Notice of Partial Deletion of Operable Unit 8, California Gulch Superfund Site, Lake County,
Colorado. EPA Region 8. October 2009.

Direct Final Notice of Partial Deletion of Operable Unit 9, California Gulch Superfund Site, Leadville, Colorado.
EPA Region 8. January 2002.

Direct Final Notice of Partial Deletion of Operable Unit 9, California Gulch Superfund Site, Leadville, Colorado.
EPA Region 8. May 2011.

Draft Monitoring and Maintenance Plan, Operable Unit 11, California Gulch Superfund Site, Leadville, Colorado.
U.S. EPA Region 8. March 16, 2010.

Ecological Risk Assessment for the Terrestrial Ecosystem, California Gulch Superfund Site, Leadville, Colorado.
EPA Region 8. January 1997.

Explanation of Significant Differences, Operable Unit 4, California Gulch Superfund Site, Leadville, Colorado.
July 2013.

Explanation of Significant Differences, Operable Unit 10, California Gulch Superfund Site, Leadville, Colorado.
EPA Region 8. July 2013.

Explanation of Significant Differences, D&RGW Slag Piles and Easement, Operable Unit 3, California Gulch
Superfund Site, Leadville, Colorado. EPA Region 8. August 2014.

Explanation of Significant Differences, Malta Gulch Fluvial Tailing/Leadville Corporation Mill/Malta Gulch
Tailing Impoundments, Operable Unit 2. California Gulch Superfund Site, Lake County, CO. July 2013.

A-2

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Explanation of Significant Differences, Residential Populated Areas Operable Unit 9, California Gulch Superfund
Site, Lake County, Colorado. EPA Region 8. September 2009.

Explanation of Significant Differences, Upper California Gulch, Operable Unit 4, California Gulch Superfund
Site, Leadville, CO. March 2004.

Explanation of Significant Differences, Yak Tunnel, Operable Unit 1, California Gulch Superfund Site, Leadville,
Colorado. EPA Region 8. October 1991.

Explanation of Significant Differences, Yak Tunnel, Operable Unit 1, California Gulch Superfund Site Lake
County, Colorado. July 2013.

Fifth Five-Year Review Report for California Gulch Superfund Site, Leadville, Colorado. EPA Region 8.
September 2017.

Final Focused Feasibility Study, Operable Unit 7, Apache Tailing Impoundments, California Gulch Superfund
Site, Leadville, Colorado. MFG, Inc. January 17, 2000.

Final Focused Feasibility Study for Upper California Gulch Operable Unit 4, California Gulch Superfund Site,
Leadville, Colorado. TerraMatrix and Shepherd Miller Incorporated. January 1998.

Final Modification of 1994 Consent Decree with ASARCO. U.S. Department of Justice. June 2008.

First Five-Year Review Report for California Gulch Superfund Site. EPA Region 8. February 2, 1996.

Focused Feasibility Study, Operable Unit 6, California Gulch Superfund Site, Leadville, Colorado. HDR
Engineering, Inc. September 2002.

Focused Feasibility Study, Operable Unit 12, California Gulch Superfund Site, Leadville, Colorado, HDR.
November 2007.

Fourth Five-Year Review Report for California Gulch Superfund Site, Leadville, Colorado. EPA Region 8.
September 2012.

Lake County Blood-Lead Program 2010 Blood-Lead Testing Annual Report. Lake County Public Health Agency.
2010.

Lake County Ordinance, Resolution 2013-3. Amending the Lake County Land Development Code and Adopting
Regulations Concerning Institutional Control for Operable Units 2 and 5 within the California Gulch Superfund
Site. April 2013.

Memorandum of Understanding Between Union Pacific Railroad, Lake County, and EPA on the Mineral Belt
Trail Project. Union Pacific Railroad and Lake County Board of Commissioners. July 1998.

Minor ROD Modification, OU5. California Gulch Superfund Site, Leadville, Colorado. EPA Region 8. May
2013.

Minor ROD Modification, OU9. California Gulch Superfund Site, Leadville, Colorado. EPA Region 8. May
2013.

Monitoring and Maintenance Report, Operable Unit 11. California Gulch Superfund Site, Leadville, Colorado.
URS Operating Services, Inc. June 20, 2011.

National Oil and Hazardous Substances Pollution Contingency Plan; National Priorities List: Partial Deletion of

A-3

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the California Gulch Superfund Site OU4, 5 and 7. October 24, 2014.

Notice of Intent to Partial Delete Operable Unit 2, California Gulch Superfund Site, EPA Region 8. May 24,

2011.

Operations and Maintenance Facility 2016 Inspection for Operable Units 2, 5 and 7. Prepared by Tetra Tech.
February 23, 2017.

Operations & Maintenance Plan for Operable Units 4, 8 and 10; Rebecca Thomas' Comments; MGF, Inc. October
2007.

Overflow Contingency Plan, Leadville Drainage Tunnel - Remedial Mikado Pond, Operable Unit 6, California
Gulch Superfund Site, Leadville, Colorado. EPA Region 8.

Partial deletion of the of the California Gulch Superfund Site. OU1 (Y ak Tunnel/Water Treatment Plant) and OU3
(Denver & Rio Grande Western Railroad Company (D&RGW) Slag Piles/Railroad Easement/Rai 1 road Yard) by
the EPA. Federal Register/Vol. 81, No. 26. February 9, 2016.

Partial Deletion of the California Gulch Superfund Site. OU02 by the EPA Federal Register/Vol. 66. No. 99. May
22. 2001.

Partial Deletion of the California Gulch Superfund Site. OUs 4, 5 and 7 by the EPA. Federal Register/Vol. 79, No.
206/Friday, October 24, 2014.

Partial Deletion of the California Gulch Superfund Site. OU 8 by the EPA. Federal Register/Vol. 74, No. 218.
November 13, 2009.

Partial Deletion of the California Gulch Superfund Site. OU09 - subunits A and B. residential waste rock piles,
and the parks and playgrounds by the EPA. Federal Register/Vol. 67. No. 34. February 20, 2002.

Partial Deletion of the California Gulch Superfund Site. OU 10 by the EPA. Federal Register/Vol. 66. No. 32.

February 15, 2001.

Partial Deletion of the of the California Gulch Superfund Site. Remaining portions of OU 9 by the EPA. Federal
Register/Vol. 76. No. 183. September 21. 2011.

Pollution Report, Operable Unit 2 Leadville Corporation Lab, California Gulch Superfund Site, Leadville, Lake
County, Colorado. EPA Region 8. June 2004.

Pollution/Situation Report, Acid Rock Drainage Controls, Operable Unit 6, California Gulch Superfund Site,
Leadville, Colorado. EPA Region 8. October 29, 2014.

Pollution/Situation Report, Stray Horse Gulch, Operable Unit 6, California Gulch Superfund Site, Leadville,
Colorado. EPA Region 8. December 16, 2013.

Record of Decision, Operable Unit 1, California Gulch Superfund Site, Leadville, Colorado. EPA Region 8.

March 29, 1988.

Record of Decision, Operable Unit 2, California Gulch Superfund Site, Leadville, Colorado. EPA Region 8.
September 1999.

Record of Decision, Operable Unit 3, California Gulch Superfund Site, Leadville, Colorado. EPA Region 8. May
6, 1998.

A-4

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Record of Decision, Operable Unit 4, California Gulch Superfund Site, Leadville, Colorado. EPA Region 8.

March 31, 1998.

Record of Decision, Operable Unit 5, AV/CZL Sites, California Gulch Superfund Site, Leadville, Colorado. EPA
Region 8. September 2000.

Record of Decision, Operable Unit 5, EGWA Sites, California Gulch Superfund Site, Leadville, Colorado. EPA
Region 8. October 31, 2000.

Record of Decision, Operable Unit 6, California Gulch Superfund Site, Leadville, Colorado, EPA Region 8.
September 2003.

Record of Decision, Operable Unit 7, California Gulch Superfund Site, Leadville, Colorado. EPA Region 8. June
2000.

Record of Decision, Operable Unit 8, California Gulch Superfund Site, Leadville, Colorado. EPA Region 8.
September 2000.

Record of Decision, Operable Unit 9, California Gulch Superfund Site, Leadville, Colorado. EPA Region 8.
September 1999.

Record of Decision, Operable Unit 10, California Gulch Superfund Site, Leadville, Colorado. EPA Region 8.
August 8, 1997.

Record of Decision, Operable Unit 11, California Gulch Superfund Site, Leadville, Colorado. EPA Region 8.
September 2005.

Record of Decision, Operable Unit 12, California Gulch Superfund Site, Leadville, Colorado. EPA Region 8.
September 2009.

Record of Decision Amendment, Operable Unit 6 Record of Decision for the Stray Horse Gulch. California Gulch
Superfund Site. EPA Region 8. September 2010.

Record of Decision Modification, Yak Tunnel Operable Unit, California Gulch Superfund Site, Leadville,
Colorado. EPA Region 8. March 1989.

Record of Decision Modification, Yak Tunnel Operable Unit, California Gulch Superfund Site, Leadville,
Colorado. EPA Region 8. March 30, 2011.

Remedial Action Completion Report, Operable Unit 6, Stray Horse Gulch, California Gulch Superfund Site,
Leadville, Colorado. US EPA Region 8. June 2013.

Remedial Action Completion Report, Operable Unit 10, California Gulch Superfund Site, Leadville, Colorado.
Shepherd Miller, Inc. and Montgomery Watson Mining Group. November 1999.

Remedial Action Completion Report Record of Preparation Review and Approval, California Gulch Superfund
Site Operable Unit 9, Populated Residential Areas. EPA Region 8. January 2011.

Remedial Action Construction Activities for Operable Unit 4 Are Now Complete, California Gulch Superfund
Site, Leadville, Colorado. EPA Region 8. Letter. December 2003.

Remedial Action Report, Operable Unit 11, California Gulch Superfund Site, Leadville, Colorado. EPA Region 8.
June 13, 2013.

A-5

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Remedial Action Report, Revision 1, Remedial Action, California Gulch, Operable Unit 5, Arkansas Valley /
Colorado Zinc Lead Sites, Lake County, Colorado. Pacific Western Technologies, LTD. February 2010.

Remedial Design Report, Operable Unit 12, California Gulch Superfund Site, Leadville, Colorado. Tetra Tech.
April 2015.

Resolution Amending the Lake County Land Development Code and Adopting Regulations Concerning
Institutional Controls for Seventeen Mine Waste Pile Located in Operable Unit 9 within the California Gulch
Superfund Site. Proceeding of the Board of County Commissioners. County of Lake and State of Colorado.
December 2009.

Routine Monitoring Plan, Yak Tunnel Operable Unit, California Gulch Superfund Site, Leadville, Colorado.
Prepared by MFG, Inc. for EPA Region 8. April 2008.

Second Amendment to Administrative Order for Yak Operable Unit Remedial Design/Remedial Action,
California Gulch Superfund Site, Leadville, Colorado. EPA Region 8. June 16, 1993.

Second Five-Year Review Report for California Gulch Superfund Site. Prepared for EPA Region 8 by
TechLaw, Inc. September 29, 2001.

Third Five-Year Review Report for California Gulch Superfund Site, Leadville, Colorado. Prepared for EPA
Region 8 by HDR Engineering, Inc. September 28, 2007.

Transmittal of First Amendment to Administrative Order for Yak Tunnel Operable Unit Remedial
Design/Remedial Action (With Unilateral Administrative Order 89-20 Attached), California Gulch Superfund
Site, Leadville, Colorado. EPA Region 8. April 30, 1993.

Work Plan for the Lake County Community Health Program Phase 2. Lake County Board of County
Commissioners, Lake County Public Health Agency, Colorado Department of Public Health and
Environment, and EPA Region 8. February 2009.

Work Plan for the Lake County Community Health Program Phase 2 - Revision 1. Lake County Board of County
Commissioners, Lake County Public Health Agency, Colorado Department of Public Health and
Environment, and EPA Region 8. October 2013.

A-6

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APPENDIX B - SITE CHRONOLOGY

Superfund Enterprise Management System (SEMS) document numbers are included in the tables below for
reference - SEMS is the EPA's internal document system. Some documents are publicly available at
https://www .epa. gov/superfiind/california-gulch. If documents are not available on the website, contact EPA
Region 8's Information Service Center at https://www.epa.gov/aboutepa/epa-region-8s-information-center.

Table B-l: Site Chronology

Silo r.\enl

Diilo

Placer gold discovered in California Gulch and mining began in the Leadville Mining Area District.

1859

The Harrison Reduction Works in 0U3, the only smelter reported to have processed gold ores, opened on
the northeast corner of Harrison Avenue and Elm Street in 1877; it closed in 1893.

1877-1893

The Grant Smelter was in operation.

1878-1882

Berdell and Witherell Smelter operated near the La Plata slag pile in 0U3.

1878-1887

0U2 area was developed with placer claims.

1879-1882

The Cummings and Finn Smelter Works began operations at Big Evans Gulch in 1879. The plant, which
also operated under the name of the Fryer Hill Smelting Company, was dismantled in 1886. Other
smelters that operated in the Big Evans Gulch Area included the Ohio and Missouri Smelter, the Gage-
Hagaman Smelter, and the Raymond, Sherman and McKay Smelter.

1879-1886

The Elgin Smelter operated intermittently.

1879-1903

The Elgin, Grant and Arkansas Valley (AV) smelters in 0U5 were constructed. The AV Smelter
processed lead ore and reprocessed slag to produce lead, silver and other metals. It operated until 1961.

1879-1961

The AV Smelter operated in 0U5.

1882-1960

The Union Smelter was in operation.

1892-1900

Bimetallic Smelting Company leased the La Plata area in 0U3 for pyritic smelting of low-grade ores.

1892-1900

The Elgin Smelter works in 0U5 were leased and operated by several different companies.

1893-1902

Yak Tunnel driven to dewater mines and facilitate mineral exploration and development in OU1.

1895

The American Smelting and Refining Company purchased the La Plata works in 0U3 in 1900.

1900

The Western Zinc Mining and Reducing Company constructed a smelter to the west of Leadville in 0U5
that extracted zinc from ores.

1914-1926

Harrison Recovery Works was established to rework the Harrison Street slag pile in 0U3.

1917

Last extension to Yak Tunnel occurred - total length of tunnel measures 3.5 to 4 miles into Iron Hill and
Breece Hill in OU 1.

1923

The CZL Site operated a flotation mill that processed zinc and lead ores sporadically between 1925 and
1940. The tailings impoundment at the CZL Site is only tailings impoundment in 0U8.

1925-1940

The Colorado Zinc-Lead Mill in 0U5 began processing ores with a custom flotation process to produce
zinc, lead, gold, silver and some copper concentrations. The mill closed in 1930 but was remodeled in
1935. Between 1935 and 1938, when it closed for good, the mill processed ores from several local mines
and waste dumps. The history of the AV and the Grant/Union smelters indicated disposal of slag at this
area.

1926-1938

The mill that generated the tailings placed in the Main Impoundment, and possibly the North
Impoundment in OU7, was located on the hillside northeast of the North Impoundment. This mill was
known as the Venir Mill, the California Gulch Mill and the ASARCO Leadville Milling unit.

1939-1956

Ore & Chemical Company used OU2 as a disposal area.

1943-1946

The Oregon Gulch Tailing Impoundment in OUIO received tailings from the Newmont/Resurrection-
ASARCO mill in California Gulch.

1945-1957

Hecla Mining Company, which later purchased Day Mines (Hecla/Day), leased the 0U2 property.

1947-1987

D&RGW purchased the AV Smelter slag pile in 0U3 from ASARCO for use as ballast.

1961

Leadville Corporation purchased the 0U2 property.

1968

D&RGW purchased the La Plata Slag Pile in 0U3 from the Leadville Sanitation District in 1970.

1970

The Apache Mill began operations in the late 1970s and continued operations into the 1980s.

1970s-1980s

A mill facility used a cyanide leach process to extract silver from ore obtained from the Sherman and
Diamond Newmont/Resurrection mines. Leadville Corporation purchased the mill in the early 1980s. It
continued operating until the mill closed in 1986.

1970s-1986

D&RGW purchased the Harrison Street Slag Pile in OU3 from NL Industries for use as a ballast
production.

1983

B-l

-------
Siic l.\oii(

Dull*

Leadville Silver & Gold operated a pyrite recovery process at OU2.

1983-198X

The EPA listed the Site on the NPL.

9/8/1983

The EPA signed the ROD for OU1.

3/29/1988

The EPA signed the ROD Mod for OU 1.

3/23/1989

The EPA signed the ESD for OU 1.

10/22/1991

Yak Tunnel WTP began treating Yak Tunnel discharge.

1992

Sitewide Consent Decree - SEMS#303506.

5/16/1994

The EPA signed the Site's first FYR Report.

2/2/1996

ROD signed for OU 10 - Oregon Gulch.

8/8/1997

ROD signed for OU4 - Upper California Gulch.

3/31/1998

ROD signed for OU3 - D&RGW Railroad Slag Piles, Easement, Yard, and the Mineral Belt Trail.

5/6/1998

ROD signed for OU2 - Malta Gulch.

9/30/1999

ROD signed for OU7 - Apache Tailing Impoundments.

6/6/2000

ROD signed for OU8 - Lower California Gulch.

9/29/2000

ROD signed for OU5 - slag and soils for Elgin Smelter, Grant/Union Smelter, Western Zinc Smelter and

9/29/2000

AV South Hillside Slag sites.

ROD signed for OU5 - tailings, flue dust and non-residential soils for AV Smelter and CZL Mill sites.

10/31/2000

OU 10 partially deleted from the NPL.

4/16/2001

Notice of Partial Deletion of OU2 from the NPL.

7/23/2001

The EPA signed the Site's second FYR Report.

9/28/2001

Notice of Partial Deletion of the parks and playgrounds, residential mine waste rock piles, and Subunits A

4/22/2002

and B in OU9 from the NPL.

OU7 Apache Tailing Impoundments capped.

6/24/2002

The EPA signed the OU6 ROD, encompassing previous removal actions.

9/25/2003

The EPA signed the ESD for OU4.

3/17/2004

The EPA signed the ROD for OU 11 - Arkansas River Floodplain.

9/28/2005

Various response actions performed by parties to the Consent Decree.

1994-2006

The EPA signed the Site's third FYR Report.

9/28/2007

State of Emergency in Lake County due to water levels in the LMDT.

2/1/2008

Relief well installed in the LMDT to pump water to the LMDT treatment plant.

3/1/2008

The second EPA-lead sitewide technical assistance grant was completed.

5/1/2008

Sitewide claim in ASARCO bankruptcy proceeding.

5/1/2008

Final Consent Decree with Newmont USA and Newmont/Resurrection Mining Company

6/26/2008

Final Modification of 1994 Consent Decree with ASARCO

7/2/2008

The EPA signed the ROD for OU12 (Sitewide Water Quality).

9/22/2009

Lower California Gulch (OU8) partially deleted from the NPL.

1/12/2010

The EPA signed the ROD Amendment for OU6.

9/28/2010

Residential areas (OU9) partially deleted from NPL.

9/21/2011

The EPA signed the Site's fourth FYR Report.

9/27/2012

ROD Mod - ASARCO Smelters/Slag/Mill Sites (OU5) - SEMS#1261492.

5/16/2013

ROD Mod - Apache Tailing Impoundments (OU7) - SEMS#1261491.

5/16/2013

ROD Mod - Lower California Gulch (OU8) - SEMS#1261490.

5/16/2013

ROD Mod - Residential Soils (OU9) - SEMS#1261489.

5/16/2013

Repository completion - Stray Horse Gulch (OU6) - SEMS#1265520.

6/13/2013

The EPA signed the ESD for OU1 (Yak Tunnel) - SEMS#1267311.

7/29/2013

EPA signed the Malta Gulch Fluvial Tailing/Leadville Corporation Mill/Malta Gulch Tailing
Impoundments (OU2) ESD - SEMS#1267312.

7/29/2013

The EPA signed the ESD for OU4 (Upper California Gulch) - SEMS#1267313.

7/29/2013

ESD Oregon Gulch (OU10) - SEMS#1267314.

7/29/2013

ESD D&RGW Slag Piles and Easement (OU3) - SEMS#1286501.

8/6/2014

Upper California Gulch (OU4), ASARCO Smelters/Slag/Mill Sites (OU5) and Apache Tailing
Impoundments (OU7) partially deleted from NPL - SEMS#1310757.

10/24/2014

Yak Tunnel (OU 1) and DR&G Slag Piles (OU3) partially deleted from the NPL.

4/11/2016

B-2

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Table B-2: Chronology of OU1 Events

()l 1 i:\onl

Diilc

The EPA placed the California Gulch Superfund site on the NPL.

9/8/1983

Phase IRI Report complete - SEMS#325440, 308998, 309003.

5/1987

FS Report complete - SEMS#314983.

6/1/1987

Proposed Remedial Action Plan complete for OU1 - SEMS#333922.

12/7/1987

ROD signed - SEMS#334261.

3/29/1988

Surge pond and interim treatment plant remedy began.

9/1988

ROD Mod (AROD) - SEMS#316277.

3/23/1989

Unilateral Administrative Order (UAO 89-20) - SEMS#304436.

3/29/1989

Construction of Yak Tunnel WTP began.

2/1990

Surge pond and interim treatment plant remedy completed.

6/1991

ESD signed - SEMS#304397.

10/22/1991

Completion of Yak Tunnel monitoring wells - SEMS#2041904.

2/1/1992

Completion of the Yak Tunnel WTP facility - SEMS#320890-96.

2/1992 to
1/1/1993

First amendment to UAO 89-20 - SEMS#309585.

4/30/1993

Second amendment to UAO 89-20 - SEMS#318526.

6/16/1993

Yak Tunnel bulkhead remedy began.

3/1994

Consent Decree with ASARCO - SEMS#303506.

5/16/1994

Completion of the Yak Tunnel bulkhead remedy.

11/1994

Rising water levels detected in the Yak Tunnel.

5/2002

Dewatering of Black Cloud Mine underway.

3/2006

The EPA and the Site's PRPs signed a Consent Decree for performance of remedy and O&M activities -
SEMS#1073144 (this Consent Decree replaced UAO 89-20).

6/26/2008

Environmental covenants placed - SEMS#1242260-62.

7/31/2012

and
10/10/2012

ESD added institutional controls - SEMS#1267311.

7/29/2013

OU partial deletion from the NPL.

4/11/2016

The EPA approved a permanent change for the effluent to be discharged from the Yak Tunnel WTP at a
more alkaline pH

5/9/2018

"able B-3: Chronology of OU2 Events

()l 2 l.\cn(

Diilo

California Gulch Superfund site placed on the NPL.

9/8/1983

Phase I RI Report issued - SEMS#325440, 308998, 309003.

5/1/1987

AOC for EE/CA at the MGTI signed - SEMS#318530.

9/1991

Partial Consent Decree with Hecla Mining Company to settle Hecla's sitewide liabilities - SEMS#301459
and 316075.

1/6/1993

and
8/17/1994

Partial Consent Decree with Leadville Silver and Gold Company to settle its sitewide liabilities -
SEMS#316469.

9/3/1993

EE/CA issued for the MGTI - SEMS#309834.

8/2/1993

Action Memorandum issued for removal action at the MGTI - SEMS#315870.

9/10/1993

Action Memorandum issued for time-critical removal action at the LMGFT - SEMS#317241.

8/14/1995

Start date for removal action at the LMGFT (8/14/1995 Action Memorandum).

9/5/1995

Start date for removal action at the MGTI (9/10/1993 Action Memorandum).

10/5/1995

Action Memorandum issued for time-critical removal action at the MTI - SEMS#321257.

8/9/1996

Start date for time-critical removal action at the MGTI (8/9/1996 Action Memorandum).

9/4/1996

Discovery of drums at the Leadville Mill.

11/7/1997

Completion of removal actions identified in Action Memoranda dated 9/10/1993, 8/14/1995 and
8/9/1996.

3/31/1997

Action Memorandum issued for time-critical removal action of Leadville Mill drums - SEMS#346866.

4/15/1998

Time-critical drum removal action completed.

7/2/1998

B-3

-------
()l 2 l.\cn(

Diilc

Final pollution reports on 9/10/1993, 8/14/1995, 8/9/1996 Action Memorandum issued - SEMS#323615,
323616 and 323617.

8/18/1998

ROD signed - SEMS#211888.

9/30/1999

Notice of intent to partial delete OU2 from the NPL - SEMS#493090, 493091.

2/12/2001

Partial deletion from the NPL - SEMS#1249430.

7/23//2001

The EPA issued a lien on the PRPs' property.

9/23/2002

Lake County passed ordinance that acts as an institutional control - SEMS#1261487.

4/15/2013

ESD signed adding institutional controls - SEMS#1267312.

7/29/2013

O&M Plan finalized - SEMS#1283390.

3/20/2014

Table B-4: Chronology of Removal Actions at OU2

Area

Action
Mcmomiuliim
Diilc

Kcmo\;il Action Tiikcn

Sliirl
Diilc

( oiii plot ion
Diilc

MGTI&
Leadville
Corporation
Mill

9/10/1993

1. Grade and revegetate contiguous fluvial tailings.

2. Remove non-contiguous pockets of fluvial tailings and
dispose of the material in the MGTI.

3. Provide for long-term maintenance and monitoring.

10/05/1995

3/17/1997

LMGFT

8/14/1995

1. Grade and revegetate contiguous fluvial tailings.

2. Remove non-contiguous pockets of fluvial tailings and
dispose of the material in the MGTI.

3. Provide for long-term maintenance and monitoring.

9/05/1995

3/17/1997

MTI

8/09/1996

1. Grade, compact and revegetate the impoundments.

2. Dispose of pyritic materials from the Apache Energy &
Minerals property.

3. Provide for long-term maintenance and monitoring of
the vegetated cap/cover.

9/04/1996

3/31/1997

Leadville
Drums

4/15/1998

4. Stage 42 drums in a secure location.

5. Dispose or recycle oily liquids in accordance with
Standards for the Management of Used Oil, 40 CFR
279.

6. Transport hazardous wastes to a Resource Conservation
and Recovery Act (RCRA)-approved treatment or
disposal facility.

5/26/1998

7/02/1998

Table B-5: Chronology of OU3 Events

()l 3 l.\cnl

Diilc

California Gulch Superfund site placed on the NPL.

9/8/1983

The EPA's contractor sampled the three slag piles as part of the Site's RI.

1986

Phase I RI Report issued - SEMS#325440, 308998, 309003.

5/1/1987

Soils investigation conducted that included sampling of slag from the Harrison Street Pile, La
Plata Pile, and an area west of Leadville (AV Smelter Slag Pile not included).

1988

The EPA conducted second sampling of slag to determine the concentrations of metals in three
D&RGW slag piles and to evaluate potential of migration.

5/1989

AOC with D&RGW for RI/FS of slag piles - SEMS# 1020621.

12/3/1991

RI/FS completed for seven major lead slag piles and a zinc slag pile - SEMS#305053, 303054,
307275.

12/11/1992

Sitewide Screening Feasibility Study (SFS) completed - SEMS#301445.

9/1/1993

AOC with D&RGW for completion of investigation and remediation activities - SEMS#301431.

9/15/1993

The EPA, the State and D&RGW entered into Consent Decree - SEMS#318593.

12/1993

D&RGW submitted ballast operations plan to the EPA.

7/1995

Ballast operations commenced.

8/1995

D&RGW submitted a feasibility study for the stockpiled fine slag at the AV Smelter slag pile
according to Consent Decree terms - SEMS#320758.

5/13/1996

B-4

-------
()l 3 i:\cni

I);ik*

UP assumed D&RGW's responsibilities at the Site.

1996

ROD signature for OU3 (addressed only the fine slag stockpiled as a subpile of the AV Smelter
Slag Pile) - SEMS#323545.

5/6/1998

Request for Partial Deletion of the Mineral Belt Trail from the State of Colorado to the EPA -
SEMS#493093.

11/3/2000

Lake County adopted ordinance that acts as an institutional control - SEMS#1100390.

3/3/2009

City of Leadville adopted ordinance that acts as an institutional control - SEMS#1265522.

5/7/2013

ESD requiring institutional controls signed - SEMS# 1286501.

8/6/2014

OU3 partial deletion from the NPL.

4/11/2016

Table B-6: Chronology of OU4 Events

()l 4 I.mmh

Diilc

California Gulch Superfund Site placed on the NPL.

9/8/1983

Final Yak Tunnel/California Gulch RI Report issued.

1986

PRP began the RI//FS

4/7/1987

Phase I RI Report issued - SEMS#325440, 308998, 309003.

5/1/1987

Newmont/Resurrection entered into a Consent Decree with the United States, the State of
Colorado, and other PRPs to perform remediation work in OU4 - SEMS#303506.
PRP completed the RI/FS

8/26/1994

EE/CA issued for Upper California Gulch - SEMS#316970.

7/1995

Action Memorandum issued for removal action at the Garibaldi Mine Site - SEMS#317242.

8/04/1995

Start date for removal action at Garibaldi Mine Site (08/04/1995 Action Memorandum).

9/22/1995

Action Memorandum issued for time-critical removal action at a portion of Upper California
Gulch-SEMS#320169.

10/31/1995

Completion of removal action at Garibaldi Mine Site (08/04/1995 Action Memorandum).

1/1996

Action Memorandum issued for removal action at the Whites Gulch Sub-basin - SEMS#321250.

7/19/1996

Start date for removal action at the Whites Gulch Sub-basin, Agwalt Mine Site (07/19/1996
Action Memorandum).

8/28/1996

Start date for time-critical removal action at a portion of Upper California Gulch (10/31/1995
Action Memorandum).

10/03/1996

Action Memorandum amendment to July 19, 1996 Memorandum. Amendment deleted the
removal action at the Waste Rock Pile UCG-92A - SEMS#321523.

11/18/1996

Completion of the Whites Gulch Sub-basin (Agwalt Mine) and a portion of Upper California
Gulch (10/31/1995 and 07/19/1996 Action Memorandum).

7/1997

The EPA issued Proposed Plan.

1/01/1998

OU4 ROD issued - SEMS#1141259.

3/31/1998

Final Pollution Report issued, for non-time-critical removal action for the Garbaldi Mine -
SEMS#323550.

6/30/1998

Remedial action - SEMS#2008363.

1998-2001

Construction Completion Report issued - SEMS#2032908.

2/1/2003

ESD deferred remedial action at Oro City to OU12 - SEMS#2008232.

3/17/2004

Consent Decree with Newmont/Resurrection - SEMS#1073144.

6/24/2008

Lake County adopts ordinance that acts as institutional control - SEMS#1261484.

12/22/2010

Environmental Covenants placed on Newmont/Resurrection properties - SEMS#1242260,
1242261, 1242262.

7/31/2012, 10/1/2012

ESD signed that requires institutional controls - SEMS#1267313.

7/29/2013

Partial deletion from the NPL - SEMS#1310757.

10/24/2014

Table B-7: Chronology of OU5 Events

()l 5 i:\enl

Diilo

California Gulch Superfund site placed on NPL.

9/8/1983

Phase I RI Report issued - SEMS#325440, 308998, 309003.

5/1/1987

The EPA and ASARCO entered into AOC for performance of soils sampling and air monitoring
- SEMS#303835.

9/1/1990

B-5

-------
015 i:\oni

Diilo

The EPA issued a UAO and first and second amendments requiring ASARCO to conduct studies

8/29/1991, 11/20/1991.

and complete RIs - SEMS#303587, 303625, 318527.

and 9/12/1991

Smelter site reconnaissance conducted - SEMS#304533.

1991 - 1993

Surface water RI conducted.

1991

Hydrogeologic RI conducted.

1991 - 1992

SFS conducted to initiate the overall CERCLA FS.

1993

Smelter RI Report issued - SEMS#303553, 303554, 303555.

4/28/1993

ASARCO entered into Consent Decree with United States, the State and other PRPs. ASARCO

8/26/1994

agreed to perform certain remediation work in OU5, OU7 and OU9 - SEMS#316074, 303506.

Final Surface Water RI Report issued - SEMS#1077124, 320875.

5/1/1996

Final Hydrogeologic RI Report issued - SEMS#320877.

5/1/1996

FFS - EGWA Sites submitted by ASARCO - SEMS#323796.

4/1/1999

FFS - AV Smelter and Colorado Zinc-Lead Mill Site submitted by ASARCO - SEMS#287877.

2/1/2000

Proposed Plan describing the EPA's preferred alternative issued - SEMS#367805, 367806.

7/1/2000

ROD issued for AV/CZL Site - SEMS#479438.

9/29/2000

ROD issued for EGWA Site - SEMS#479625.

10/31/2000

ASARCO conducted demolition activities.

2004

MFG remedial design approved - Final Remedial Design Report, AV Smelter and Colorado
Zinc-Lead Mill Site - SEMS#2032907.

4/12/2005

ASARCO conducted remedial actions.

2004-2007

PWT remedial design approved - AV Smelter and Colorado Zinc Lead Site, Remedial Action

6/19/2009

Construction Package.

Remedial action construction mobilization.

7/2009

Final inspection, remedial action field work completed

10/23/2009

Final Remedial Action Report issued - SEMS#1142161.

2/23/2010

Lake County adopts ordinance that acts as institutional control - SEMS#1261487.

4/15/2013

City of Leadville adopts ordinance that acts as institutional control - SEMS#1265522.

5/7/2013

Minor ROD Mod clarified institutional controls - SEMS#1261492.

5/16/2013

O&M Plan finalized - SEMS#1283390.

3/20/2014

OU5 partially deleted from the NPL - SEMS#1310757.

10/24/2014

California Gulch Superfund site placed on the NPL.

9/8/1983

Phase I RI Report issued - SEMS#325440, 308998, 309003.

5/1/1987

The EPA and ASARCO entered into AOC for performance of soils sampling and air monitoring
- SEMS#303835.

9/1/1990

The EPA issued a UAO and first and second amendments requiring ASARCO to conduct

8/29/1991, 11/20/1991,

studies and complete RIs - SEMS#303587, 303625, 318527.

and 9/12/1991

Smelter site reconnaissance conducted - SEMS#304533.

1991 - 1993

Surface Water RI conducted for the Site.

1991

Hydrogeologic RI conducted for the Site.

1991 - 1992

SFS conducted to initiate the overall CERCLA FS.

1993

Smelter RI Report issued - SEMS#303553, 303554, 303555.

4/28/1993

ASARCO entered into a Consent Decree with the United States, the State and other PRPs.



ASARCO agreed to perform certain remediation work in OU5, OU7 and OU9 - SEMS#316074,

8/26/1994

303506.



Final Surface Water RI Report issued - SEMS#1077124, 320875.

5/1/1996

Final Hydrogeologic RI Report issued - SEMS#320877.

5/1/1996

FFS Report - EGWA Sites submitted by ASARCO - SEMS#323796.

4/1/1999

FFS Report - AV Smelter and Colorado Zinc-Lead Mill Site submitted by ASARCO -

2/1/2000

SEMS#287877.

Proposed Plan describing the EPA's preferred alternative issued - SEMS#367805, 367806.

7/1/2000

ROD signed for the AV/CZL Site - SEMS#479438.

9/29/2000

ROD signed for the EGWA Site - SEMS#479625.

10/31/2000

ASARCO conducted demolition activities.

2004

MFG remedial design approved - Final Remedial Design Report, AV Smelter and Colorado
Zinc-Lead Mill Site - SEMS#2032907.

4/12/2005

ASARCO conducted remedial actions.

2004-2007

B-6

-------
015 i:\oni

Diilo

PWT remedial design approved - AV Smelter and Colorado Zinc Lead Site, Remedial Action
Construction Package.

6/19/2009

Remedial action construction mobilization.

7/2009

Final inspection, remedial action field work completed

10/23/2009

Final Remedial Action Report issued - SEMS#1142161.

2/23/2010

Lake County adopted ordinance that acts as an institutional control - SEMS#1261487.

4/15/2013

City of Leadville adopted ordinance that acts as an institutional control - SEMS#1265522.

5/7/2013

Minor ROD Mod clarifying institutional controls - SEMS# 1261492.

5/16/2013

O&M Plan finalized - SEMS#1283390.

3/20/2014

OU5 partially deleted from the NPL - SEMS#1310757.

10/24/2014

Table B-8: Chronology of OU6 Events

()l (> r.\cn(

Diilc

California Gulch Superfund site placed on the NPL.

9/8/1983

Phase IRI Report issued - SEMS#325440, 308998, 309003.

5/1/1987

Action Memorandum for removal action at 5th Street/Starr Ditch and Runoff, including
Garibaldi, North Mike and Oregon gulches - SEMS#301684.

2/12/1991

Action Memorandum issued for time-critical removal action at the Stray Horse Gulch
Sediment Dam - SEMS#320168.

11/6/1995

Action Memorandum issued for emergency response removal action for the removal of
sediments from the 5th Street Drainage Ditch and Starr Ditch - SEMS#321329.

5/1/1996

Action Memorandum issued for time-critical removal action at the Hamm's Tailing
Impoundment and the Penrose Mine Waste Pile - SEMS#321251.

7/26/1996

EE/CA for Stray Horse Gulch - SEMS#322065.

6/1/1997

Action Memorandum issued for non-time-critical removal action for source control activities
at designated mine waste piles - SEMS#322106.

6/24/1997

Addendum to EE/CA for Stray Horse Gulch - SEMS#323567.

5/1/1998

Action Memorandum issued for subsequent non-time-critical removal actions for source
control at designated mine waste piles - SEMS#323611.

7/15/1998

Final pollution reports on 11/06/1995, 05/01/1996 Action Memorandums issued -
SEMS#323618.

8/19/1998

Action Memorandum issued for a non-time-critical removal action for water management
activities at the Newmont/Resurrection #1 Tailing Pile at the Upper End of Evans Gulch -
SEMS#323722.

10/26/1998

Final Addendum No. 2 to EE/CA for Stray Horse Gulch - SEMS#301103.

5/1/1999

Addendum to Action Memorandum issued for a non-time-critical removal action for water
management activities at the Newmont/Resurrection #1 Tailing Pile at the Upper End of
Evans Gulch (10/26/1998) - SEMS#232083.

6/2/1999

Addendum to Action Memorandum issued for subsequent non-time-critical removal actions
for source control at designated mine waste piles (07/15/1998) - SEMS#232089.

6/2/1999

Final Pollution Report issued, on 07/26/1996 Action Memorandum for time-critical removal
action at the Hamm's Tailing Impoundment and the Penrose Mine Waste Pile -
SEMS#231856.

10/4/1999

Action Memorandum issued for a time-critical removal action in the Greenback - RAM
runoff collection system - SEMS#301102.

6/20/2000

Amendment to Action Memorandum issued for a time-critical removal action in the
Greenback - RAM runoff collection system (06/20/2000) - SEMS#478818.

8/22/2000

Final Pollution Report on 06/2/2000 Action Memorandum issued - SEMS#479619.

10/16/2000

Final Phase I, II, III, IV Removal Action Completion Report issued - SEMS#1020670,
1020671, 1100381.

12/28/2000

Action Memorandum issued for Ibex/Irene waste pile - SEMS#1162658.

6/25/2001

Action Memorandum issued for Greenback, RAM and Marion Ponds - SEMS# 1202497.

7/13/2001

ROD issued - SEMS#2008670.

9/25/2003

Remedial action (removal of Ponsardine Waste Rock Pile, replacement of cribbing).

2002-2004

Construction completion achieved - Ponsardine mine waste relocation and Robert Emmet
crib wall rehabilitation - SEMS# 1022027.

11/15/2004

B-7

-------
01 (i r.\oiK

Diilc

Construction of an outlet structure on the Gaw Shaft under a non-time-critical removal action

(Site Activities Report) - SEMS#1068045.

7/14/2005

Action Memorandum issued - relief well installed during state of emergency -

SEMS#1092386.

3/12/2008

Memorandum of Understanding with the USBR issued - SEMS#1072292.

6/24/2008

Pilot study on capping alternatives issued - SEMS# 1189921.

12/20/2010

AROD signed - SEMS#1167638.

9/28/2010

Action Memorandum for Mikado Pond issued - SEMS#1202497.

7/13/2011

Action Memorandum for Mikado Pond issued - SEMS#1230841.

9/26/2011

Repository remedial design start.

10/13/2011

Repository remedial action start - SEMS#1242264.

7/9/2012

Action Memorandum for Mikado Pond issued - SEMS#1242278.

8/22/2012

Action Memorandum Amendment issued for Marion, Greenback and Adelaide ponds -

SEMS#1242277.

9/4/2012

Repository remedial design completion - SEMS#1239588.

9/6/2012

Repository remedial action completion - SEMS#1265520.

6/13/2013

Environmental covenants placed on Newmont/Resurrection properties - SEMS#1242260,
1242261 and 1242262.

7/31/2012 and 10/1/2012

City of Leadville passed ordinance on parts of OU6 within city limits - SEMS#1265522.

5/7/2013

Pollution Report issued for Marion Pond and Shaft - SEMS#1292050.

12/16/2013

Pollution Report issued for Marion and Mikado ponds - SEMS#1292075.

10/29/2014

Action Memorandum issued for Mikado Pond - SEMS# 1310761.

11/10/2014

Action Memorandum issued for Stray Horse Gulch - SEMS#1772202-R8.

6/7/2016

EPA placed the California Gulch Superfund site on the NPL.

9/8/1983

Phase IRI Report issued - SEMS#325440, 308998, 309003.

5/1/1987

Action Memorandum issued for removal action at 5th Street/Starr Ditch and Runoff,

including Garbaldi, North Mike and Oregon gulches - SEMS#301684.

2/12/1991

Action Memorandum issued for time-critical removal action at the Stray Horse Gulch

Sediment Dam - SEMS#320168.

11/6/1995

Action Memorandum issued for emergency response removal action for the removal of

sediments from the 5th Street Drainage Ditch and Starr Ditch - SEMS#321329.

5/1/1996

Action Memorandum issued for time-critical removal action at the Hamm's Tailing

Impoundment and the Penrose Mine Waste Pile - SEMS#321251.

7/26/1996

EE/CA issued for Stray Horse Gulch - SEMS#322065.

6/1/1997

Action Memorandum issued for non-time-critical removal for source control activities at

designated mine waste piles - SEMS#322106.

6/24/1997

Addendum to EE/CA for Stray Horse Gulch issued - SEMS#323567.

5/1/1998

Action Memorandum issued for subsequent non-time-critical removal for source control

activities at designated mine waste piles - SEMS#323611.

7/15/1998

Final pollution reports issued on 11/06/1995, 05/01/1996 Action Memorandums -. SEMS

#323618

8/19/1998

Action Memorandum for a Non-Time Critical Removal Action for Water Management

Activities at the Newmont/Resurrection #1 Tailing Pile at the Upper End of Evans Gulch.

SEMS #323722

10/26/1998

Final Addendum No. 2 to EE/CA for Stray Horse Gulch. SEMS #301103

5/1/1999

Addendum to Action Memorandum for a Non-Time Critical Removal Action for Water

Management Activities at the Newmont/Resurrection #1 Tailing Pile at the Upper End of
Evans Gulch (10/26/1998) - SEMS#232083.

6/2/1999

Addendum to Action Memorandum issued for subsequent non-time-critical removal for

source control activities at designated mine waste piles (07/15/1998) - SEMS#232089.

6/2/1999

Final Pollution Report issued on 07/26/1996 Action Memorandum for time-critical removal

action at the Hamm's Tailing Impoundment and the Penrose Mine Waste Pile -
SEMS#231856.

10/4/1999

Action Memorandum issued for a time-critical removal action in the Greenback - RAM

Runoff Collection System - SEMS#301102.

6/20/2000

B-8

-------
01 (i r.\oiK

Diilc

Amendment to Action Memorandum issued for a time-critical removal action in the
Greenback - RAM Runoff Collection System (06/20/2000) - SEMS#478818.

8/22/2000

Final Pollution Report on 06/2/2000 Action Memorandum issued - SEMS#479619.

10/16/2000

Final Phase I, II, III, IV Removal Action Completion Report issued - SEMS#1020670,
1020671, 1100381.

12/28/2000

Action Memorandum for Ibex/Irene waste pile issued - SEMS#1162658.

6/25/2001

Action Memorandum issued for Greenback, RAM and Marion ponds - SEMS# 1202497.

7/13/2001

ROD signed - SEMS#2008670.

9/25/2003

Remedial action completed (removal of Ponsardine Waste Rock Pile, replacement of
cribbing).

2002-2004

Construction completion achieved - Ponsardine Mine Waste relocation and Robert Emmet
Crib Wall rehabilitation - SEMS# 1022027.

11/15/2004

Construction of an outlet structure on the Gaw Shaft under a non-time-critical removal (Site
Activities Report) - SEMS#1068045.

7/14/2005

Action Memorandum issued - relief well installed during state of emergency -
SEMS#1092386.

3/12/2008

Memorandum of Understanding with the USBR issued - SEMS#1072292.

6/24/2008

AROD signed - SEMS#1167638.

9/28/2010

Pilot Study on capping alternatives issued - SEMS# 1189921.

12/20/2010

Action Memorandum for Mikado Pond issued - SEMS#1202497.

7/13/2011

Action Memorandum for Mikado Pond issued - SEMS#1230841.

9/26/2011

Repository remedial design start.

10/13/2011

Repository remedial action start - SEMS#1242264.

7/9/2012

Action Memorandum for Mikado Pond issued - SEMS#1242278.

8/22/2012

Action Memorandum Amendment issued for Marion, Greenback and Adelaide ponds -
SEMS#1242277.

9/4/2012

Repository remedial design end - SEMS#1239588.

9/6/2012

Repository remedial action completion - SEMS#1265520.

6/13/2013

Environmental covenants on placed Newmont/Resurrection properties - SEMS#1242260,
1242261 and 1242262.

7/31/2012 and 10/1/2012

City of Leadville passed ordinance for parts of OU6 within city limits - SEMS#1265522.

5/7/2013

Pollution Report for Marion Pond and Shaft issued - SEMS#1292050.

12/16/2013

Pollution Report for Marion and Mikado ponds issued - SEMS#1292075.

10/29/2014

Action Memorandum for Mikado Pond issued - SEMS#1310761.

11/10/2014

Action Memorandum for Stray Horse Gulch issued - SEMS#1772202-R8.

6/7/2016

B-9

-------
Table B-9: Chronology of Initial EPA Response Actions, OU6

Arc;i(s) AITcclcd

Action
Mcmoi'iinriiim
Diilc

Response Action T;ikcn

Sliirl
Diilc

( umplclion
Diilc

5th Street
Starr Ditch
Harrison Slag Pile

1990
Removal Action

Converted open ditches to covered culverts
along both sides of 5th Street.

Fenced Starr Ditch from just south of 5th
Street to Monroe Street, just east of the
Harrison Street slag pile.

1990

1990

Stray Horse Gulch

11/06/1995
Time-Critical
Removal Action

Removed sediment from ditches and culverts
around Hamm's Tailing Impoundment, from
the 5th Street Drainage Ditch and from Stan-
Ditch south of 5th Street.

Constructed sediment control dam across the
road from the east end of Hamm's Tailing
Impoundment.

8/25/1995

8/30/1995

5th Street Drainage

Ditch

Starr Ditch

5/01/1996

Emergency
Response
Removal Action

Removed sediment from the 5th Street
Drainage Ditch from its headwall to and along
Starr Ditch to its confluence with Lower
California Gulch.

5/06/1996

5/10/1996

Hamm's Tailing
Impoundment
Penrose Mine Waste
Pile

07/26/1996
Time-Critical
Removal Action

Transported mine waste in the Penrose Mine
Waste Pile to Hamm's Tailing Impoundment.

Revegetated the Penrose Mine Waste Pile
footprint and reshaped the Hamm's Tailing
Impoundment to a more uniform and stable
configuration.

7/26/1996

9/30/1998

Maid of Erin
Wolftone Mine
Adams Mill
Mahala Mine

06/24/1997

Non-Time-
Critical Removal
Action (Phase I)

Consolidated about 211,000 cubic yards of
waste from Maid of Erin Mine, Wolftone
Mine and Mahala Mine waste piles.

Placed liner system and rock cap over the
three consolidated waste piles.

6/24/1997

1998

B-10

-------
\iv;i(s) AITcclcd

Action
Moiiioi-iiiidiiiii
l);ilc

Response Action T;ikcn

Sliiri
Diilc

( oniplclion
Diilc





Coiibirucled surface w aler run-on di\ eiMon
channels around six mine waste rock piles.









Constructed surface water runoff collection
channels around four waste rock piles to
capture and convey impacted water to
retention basins.







07/15/1998

Constructed surface water retention basins.





Adelaide-Ward
Mikados
Highland Mary
Pyrenees

Amendment to
06/24/1997 Non-

Time-Critical
Removal Action
(Phase II)

Constructed detention basins in Lower Stray
Horse gulch to convey a 100-year storm event
and to remain stable for a 500-year storm
event.

Rehabilitated Starr Ditch from 3rd Street to
5th Street to convey a 100-year, 24-hour
storm event and to remain stable for a 500-
year storm event.

Revegetated disturbed areas as well as the
Hamm's Tailing Impoundment and Penrose
Mine Waste Pile.

1998

1999

Ponsardine Mine

RAM

Greenback

Newmont/Resurrection
No. 1/Fortune Mine

06/02/1999
Amendment to
06/24/1997 Non-

Time-Critical
Removal Action
(Phase III)

Constructed surface water run-on diversion
channels around six mine waste rock piles.

Constructed surface water runoff collection
channels around four waste rock piles to
capture and convey impacted water to
retention basins.

Constructed surface water retention basins.

1999

1999

Newmont/Resurrection
No. 1 Tailing Pile

10/26/1998 to
6/02/1999
Non-Time-
Critical Removal
Action

Installed sediment control structure in the
drainage basin downstream of the
Newmont/Resurrection No. 1 Tailing Pile.

6/8/1998

1999

B-ll

-------
\iv;i(s) AITcclcd

Action
Moiiioi-iiiidiiiii
l);ilc

Response Action T;ikcn

Sliirl
Diilc

( oniplclion
Diilc





Identified ^impeded blockage in drainage
system leading to the Greenback-RAM
collection system. Excavated blockages from
drainage pathways or modified flow paths.







6/20/2000
to

8/22/2000

Installed berm and drainage improvements
from the Greenback collection system to
direct the flow into a depression.





Greenback - RAM
Runoff

Time-Critical
Removal Action
(Phase IV)

Advanced a borehole and installed a stand-
pipe to convey ARD discharged from the
collection systems described above to the
Marion shaft adit for conveyance to the
Leadville Mine Drainage Tunnel and
ultimately to the USBR water treatment
facility.

Transferred ponded water in the RAM
collection system to the Greenback collection
system to relieve the hydraulic pressure on the
abandoned railroad grade.

Developed and implemented a Water Quality
Monitoring Plan.

6/30/2000

10/13/2000



6/25/2001

Diverted run-on around mine waste pile.





Ibex/Irene Waste Rock
Pile

Time-Critical
Removal Action
(Phase V)

Retained runoff in two impoundments to
settle out sediments that could impact
Parkville Reservoir.

6/25/2001

Fall 2001

Stray Horse Gulch

2004

Ponsardine relocation.

Robert Emmet crib wall rehabilitation.

2003

2004

Gaw Shaft

2005 Non-Time-
Critical Removal
Action

Constructed an engineered outlet for the Gaw
Shaft.

2005

2005

Stray Horse Gulch

3/12/2008
Time-Critical
Removal Action

Installed relief well into the LMDT.

2/2008

2008

Stray Horse Gulch

9/26/2011
Time-Critical
Removal Action

Pumped water from Mikado Pond to Marion
Pond.

5/2011

5/2011

Stray Horse Gulch

8/22/2012
Time-Critical
Removal Action

Cleaned out Marion, Greenback, RAM and
Mikado ponds.

Addition of signage and fencing to prevent
human exposure to contaminated water in the
ponds.

9/2012

9/2012

Action Memorandum
Amendment for
Marion, Greenback,
Adelaide Ponds -
SEMS #1242277

9/4/2012







B-12

-------
\iv;i(s) AITeck'd

Action
Moiiioi-iiiidiiiii
l);iU*

Response Action T;ikcn

Sliirl
Diilo

( oiiiplclion
l);i(c

Cleaned out Mikado. Greenback and Marion.
Added fencing to Mikado and Marion ponds.

Action Memorandum
for Mikado Pond -
SEMS #1310761

11/10/2014

Pumped ARD from Mikado and transferred it
to IBEX pond.

Repaired underground line from Marion Pond
to Marion Shaft.

Added runoffs controls in Greenback and
Marion areas.

Removed sediment from Starr Ditch.

5/22/2014

9/30/2014

Installed additional bypass drainage system in
the Marion Collection area and adjacent areas
to drain ARD into the LMDT during spring
runoff.

Widened, deepened, armored and realigned
existing diversion channel within OU6.

Action Memorandum
for a Time-Critical
Removal Action at
OU6 and OU12
SEMS# 1772202-R8

6/7/2016

Removal of excess sediment in Greenback,
RAM, Marion, Mikado, Adelaide, Highland
Mary, and Pyrenees ponds to increase the
capacity to hold ARD. Pumping of ARD from
retention ponds into the collection system.

Installed permanent pump station at the Gaw
well to manage water levels in mine pool.

Installed monitoring system to provide "real-
time" conditions of the LMDT as water is
pumped from the Gaw relief well or at
stations in the tunnel.

5/1/2015

Ongoing

Table B-10: Chronology of OU7 Events

()l -• i:\cnl

Diilo

California Gulch Superfund site placed on the NPL.

9/8/1983

Investigation study conducted by Colorado Department of Law.

1986

Investigation study conducted by the EPA.

1987

Phase IRI Report issued - SEMS#325440, 308998, 309003.

5/1/1987

Investigation study conducted by the EPA.

1989

The EPA and the PRPs entered into an AOC for the performance of soil sampling and air monitoring
- SEMS#303835

9/25/1990

The EPA issued a UAO that required ASARCO to conduct studies and complete RIs - SEMS
#303586.

8/29/1991

Tailings RI performed - SEMS#303571.

7/1/1991

Surface Water RI for the Site conducted.

1991-1192

Hydrogeologic RI for the Site conducted.

1991

SFS conducted to initiate the overall CERCLA feasibility study process - SEMS#301445.

9/1/1993

ASARCO entered into a Consent Decree with the United States, the State and other PRPs. ASARCO
agreed to perform certain remediation work in OU5, OU7, and OU9 - SEMS#316074.

8/25/1994

Final Tailing Disposal AreaRI Report issued - SEMS#318961 and 318962.

1/1994

Cultural Resources Investigations of the Apache Tailing Area Report issued - SEMS#319927

11/28/1995

B-13

-------
()l ^ i:\cnl

Diilo

Apache Tailing Impoundment Dewatering Treatability Study Work Plan issued - SEMS#318033.

9/1/1995

Action Memorandum issued for Removal (Response) Action at the Apache Energy & Minerals
property - SEMS#321253.

8/8/1996

Final Surface Water RI Report issued - SEMS#1077124, 320875.

5/1/1996

Final Hydrogeologic RI Report issued - SEMS#320877, 320878.

5/1/1996

Action Memorandum issued for Time-Critical Removal Action for Removal of Tailing Pond No. 2
and Tailing Pond No. 3 of the Apache Tailing Impoundment - SEMS#321833.

4/7/1997

Field Investigation Data Report for the Apache Tailing Supplemental RI issued - SEMS#322004.

4/7/1997

Final Pollution Reports for time-critical removal actions at Tailing Pond 2 and Tailing Pond 3 of the
Apache Tailing Impoundment, 04/1997, and Apache Energy & Minerals Property, 08/1996 -
SEMS#323571.

6/30/1998

FFS Report issued for the Apache Tailing Impoundments - SEMS#371805, 1293985.

1/17/2000

Proposed Plan for the EPA's preferred alternative remedy issued - SEMS#287726.

1/25/2000

Action Memorandum issued for time-critical removal action for the Apache Tailing Impoundment -
SEMS#287713.

1/26/2000

ROD signed - SEMS#301097.

6/6/2000

Construction Completion Report issued - SEMS#1100383.

12/1/2003

Remedial Action completed

12/17/2003

Lake County adopted ordinance that acts as an institutional control - SEMS#1261484.

12/22/2010

City of Leadville adopted ordinance that acts as an institutional control - SEM #1265522.

5/7/2013

Minor ROD Modification issued to clarify institutional controls - SEMS#1261491.

5/16/2013

O&M Plan finalized - SEMS#1283390.

3/20/2014

Partial deletion from the NPL - SEMS#1310757.

10/24/2014

Table B-ll: Chronology of Removal and Remedial Actions, OU7

AiVii

Action
Mi-mor;iii(liim
Diilc ;ind Action

Ki'sponsi- Action T;ikcn

Sliirl Diilo

Completion
Diilo

Apache Energy
& Minerals
Property

8/08/1996

Time-Critical
Removal Action

Transported drums and bags of pyrite to the MTI.

Decontaminated and demolished the Apache Mill
building and equipment.

08/08/1996

03/1997

Tailing Ponds
2 and 3

4/07/1997

Time-Critical
Removal Action

Removed Tailing Pond 2 and Tailing Pond 3, berm
material and native soil, and consolidated the
material on the Main Impoundment.

Pumped surface water ponded on Tailing Pond 2
and Tailing Pond 3 to Yak Tunnel WTP prior to
initiating excavation of tailing.

Diversion of potentially contaminated surface
runoff from the Main Impoundment to a sediment
control structure.

Protected the toe of the Main Impoundment.

4/21/1997

12/04/1997

B-14

-------
Area

Action
Memorandum
Dale ;ind Action

Response Action T;ikcn

Sliirl Diilc

Completion
Diilc

Main and
North

Impoundments

1/26/2000

Time-Critical
Removal Action

Regraded die material placed 011 the Alain
Impoundment during the removal of Tailing Ponds
2 and 3.

Regraded the eastern embankment and the
southwest embankment in the vicinity of the
wooden box culvert on the Main Impoundment.

Excavated the tailings material overlying the clay-
tile culvert at the southern edge of the Main
Impoundment.

Placed fill over a portion of the North
Impoundment.

01/2000

12/17/2003

Main and
North

Impoundments

Remedial activity
specified in the
ROD

Channelization of California Gulch through the
southern portion of the main impoundment and
construction of diversion ditches to control water
run-on and runoff.

Regraded impoundments, placed a multi-layer
composite cover (including a geosynthetic barrier)
over the tailings area, and revegetated the area.

06/2001

12/2003

Table B-12: Chronology of OU8 Events

()l S l!\cnl

Diilc

California Gulch Superfund site placed on the NPL.

9/8/1983

Final Yak Tunnel/California Gulch RI Report issued - SEMS#314479.

2/28/1986

Phase I RI Report issued - SEMS#325440, 308998, 309003.

5/1/1987

The EPA and the PRPs entered into AOCs for the performance of soil sampling and air monitoring -
SEMS#1152479, 303835.

9/28/1990

The EPA issued a Unilateral Order on Consent that required ASARCO to conduct studies and complete
RIs - SEMS#309951.

8/29/1991

Newmont/Resurrection entered into a Consent Decree with the United States, the State and other PRPs to
perform remediation work - SEMS #303506.

5/16/1994

EE/CA issued for the Lower California Gulch Colorado-Lead Zinc site - SEMS#316972.

7/1995

Action Memorandum issued for removal action at the CZL Tailing Impoundment site - SEMS#317240.

8/4/1995

Start date for removal action at CZL Tailing Impoundment site (08/04/1995 Action Memorandum).

9/4/1995

Completion of removal action at CZL Tailing Impoundment site (08/04/1995 Action Memorandum).

1/1996

Action Memorandum issued for removal action at FTSs 1, 2, 3, 6 and 8 - SEMS#323578.

6/11/1998

Final Pollution Report on 08/04/1995 Action Memorandum - SEMS#323548.

6/30/1998

Start date for removal action at FTSs 1, 2, 3, 6 and 8 (06/11/1998 Action Memorandum).

8/28/1996

Completion of removal action at FTSs 1, 2, 3, 6 and 8 (06/11/1998 Action Memorandum).

11/7/1998

Final Pollution Report on 06/11/1998 Action Memorandum - SEMS#287865.

2/5/1999

Final FFS Report issued - SEMS#322589, 287786.

9/10/1997
5/22/2000

ROD signed - SEMS#479443.

9/29/2000

Construction Completion Report issued - SEMS#2032901, 2008364.

7/1/2003
9/2/2003

Lake County ordinance implemented as institutional control - SEMS#1100390.

3/2/2009

Partial deletion from the NPL - SEMS# 100000241.

1/12/2010

Environmental covenants placed on Newmont/Resurrection properties - SEMS#1242260, 1242261,
1242262.

7/31/2012

and
10/1/2012

City of Leadville adopted ordinance as an institutional control - SEMS#1265522.

5/7/2013

B-15

-------
Table B-13: Chronology of OU9 Events

()l ') l.\Oll(

Diilo

California Gulch Superfund site placed on the NPL.

9/08/198-

Investigation study conducted by Colorado Department of Law.

1986

Emergency response at a private well - SEMS#314010.

5/22/1986

Phase IRI Report issued - SEMS#325440, 308998, 309003.

5/1/1987

The EPA and settling defendants entered into AOC for performance of soils sampling and air monitoring -
SEMS#348081.

9/28/1990

The EPA issued UAO that required ASARCO to conduct studies and complete RIs related to the
Demographics Work Plan, the Final Sampling Plan for Sampling and Analysis of Lead Occurrence Within
and Immediately Adjacent to Residences, the Soil Investigation Work Plan, the Mine Waste Pile RIs, and
other issues - SEMS#309951.

8/29/1991

The EPA issued a UAO that required Newmont/Resurrection Mining Company to conduct and complete
final Soils Investigation Work Plan - SEMS#303602.

9/10/1991

The EPA entered into an AOC with ASARCO and Newmont/Resurrection Mining Company for
performance of metals speciation program - SEMS#304400.

9/24/1991

Draft Final Report - Lead Speciation Study issued - SEMS#303552.

10/12/1992

Partial Consent Decree among United States, the State and settling defendants settling federal and state
claims for past response costs incurred prior to February 1, 1991, and February 1, 1992 - SEMS#321558.

9/4/1993

Final RI pursuant to UAO dated 09/10/1991 submitted by Newmont/Resurrection Mining Company -
SEMS#315809, 315810, 315811.

7/15/1994

Consent Decree with ASARCO and Newmont/Resurrection Mining Company to define areas of
responsibility for the two companies and the U.S. government and to develop the Kids First Work Group -
SEMS#316074.

8/26/1994

Metals Speciation Data Report submitted - SEMS#318995.

09/01/1994

EE/CA work plan prepared to evaluate lead concentrations in soils within parks and playground areas in
OU9-SEMS#318878.

11/01/1994

Initiation of LCHP/ASARCO outreach program for Kids First program.

5/25/1995

Draft Final Report for Lead Speciation not approved by the EPA - SEMS#319507.

12/05/1995

Action Memorandum issued for time-critical removal action for two residences, Kids First program, in
OU9-SEMS#318303.

10/16/1995

Draft Mine Waste EE/CA issued - SEMS#321328.

12/01/1995

Action Memoranda issued for time-critical removal actions at five separate residences, Kids First program,
in OU9.

1996

Human Health Risk Assessment issued - SEMS#319625, 319626, 316598.

1/2/1996

Responses to Comments #2, Mine Waste EE/CA from ASARCO - SEMS#321243.

7/23/1996

Action Memorandum issued for PRP-financed removal actions addressing Mine Waste Rock Piles -
SEMS#321255.

8/15/1996

Action Memoranda issued for time-critical removal actions at 15 separate residences, Kids First program,
in OU9.

1997

Final Pollution Report issued for 20 time-critical removal actions performed under the Kids First program,
OU9 during the period starting July 31, 1996, through October 30, 1997 - SEMS#323537.

5/26/1998

Action Memoranda issued for time-critical removal actions at 18 separate residences, Kids First program,
in OU9.

1998

Action Memorandum Amendment issued for time-critical removal action for PRP-financed removal
actions addressing mine waste rock piles located in the residential populated areas in OU9, dated August
15, 1996 - SEMS#323547.

7/01/1998

Final Pollution Report issued for 20 time-critical removal actions performed under the Kids First program,
OU9 during the period starting October 31, 1997, through November 6, 1998 - SEMS#323750.

12/15/1998

Action Memoranda issued for time-critical removal actions at nine separate residences, Kids First program,
in OU9.

1999

ROD for Residential Populated Areas issued - SEMS#211891.

9/02/1999

Final Pollution Report issued for three time-critical removal actions performed under the Kids First
program in OU9 during the period starting June 22, 1999, through September 30, 1999 - SEMS#211908.

10/12/1999

Final Pollution Report issued for four time-critical removal actions performed under the Kids First program
in OU9 during the period starting September 13, 1999, through November 1, 1999 - SEMS#231993.

12/01/1999

Action Memoranda issued for time-critical removal actions at two residences, Kids First program.

2000

B-16

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01 y i:\cni

I);iU*

LCCHP initiated to take the place of the interim Kids First program.

6/1/2000

Petition for a Partial Deletion of portions of OU9 - SEMS#493093, 493110.

11/03/2000

Remedial design for LCCHP.

1/2001

Leadville Kids First Program Report, 1994-1999 progress and results issued - SEMS#1081471.

2/28/2001

Waste Rock Pile completion report issued - SEMS#493113.

7/31/2001

Partial deletion of OU9 subunits

4/22/2002

LCCHP Guidelines established - SEMS#2037052.

5/2002

OU9 Performance standards met, noted in the 2005 Annual Report - SEMS#2041224.

4/1/2006

LCCHP Phase 2 Work Plan completed.

3/2009

ESD issued for 17 waste rock piles - SEMS#1118478.

9/30/2009

Lake County Board of County Commissioners amended Land Development Code; institutional controls for
17 mine waste piles - SEMS#1183308.

12/23/2009

Lake County Board of County Commissioners approved LCCHP Phase 2, the institutional control for OU9
-SEMS#1161221.

3/16/2010

Voluntary residential yard cleanups completed - SEMS#1152050, 1152052, 1193006.

Fall 2010

Notice of Intent to Partially Delete published in Federal Register.

5/24/2011

Remaining portions of OU9 partially deleted from the NPL - SEMS#1202469, 1202470.

9/21/2011

City of Leadville adopted institutional controls - SEMS#1265522.

5/7/2013

Minor ROD Mod issued, clarifying institutional controls - SEMS#1261489.

5/16/2013

LCCHP Phase 2 Revision 1 approved - SEMS#1275059.

10/23/2013

Action Memorandum issued for three residences - SEMS#1777574.

9/19/2016

"able B-14: Chronology of OU10 Events

()l 10 r.M'iii

Diilo

California Gulch Superfund site placed on the NPL.

9/08/1983

Phase IRI Report issued - SEMS#325440, 308998, 309003.

5/1/1987

Newmont/Resurrection entered into a Consent Decree and agreed to perform certain remediation work -
SEMS#303506.

5/16/1994

EE/CA issued for stream sediments in Oregon Gulch - SEMS#316972.

7/1/1995

Action Memorandum issued for PRP-financed removal action at the Oregon Gulch Stream Sediments site -
SEMS#317240.

8/04/1995

Removal Action Completion Report issued - SEMS#322119.

6/1/1997

ROD issued - SEMS#322208.

8/08/1997

O&M Plan and Final Remedial Design Report issued - SEMS#323629.

6/03/1998

Remedial Action Completion Report issued - SEMS#287878.

11/15/1999

Vegetation Monitoring Report issued - SEMS#481036.

12/05/2000

The EPA issued Notice of Intent to Partially Delete.

2/15/2001

OU10 partially deleted from the NPL - SEMS#100000238.

4/16/2001

ESD issued, clarifying institutional controls - SEMS#1267314.

7/29/2013

California Gulch Superfund site placed on the NPL.

9/08/1983

Phase I RI Report issued - SEMS#325440, 308998, 309003.

5/1/1987

Newmont/Resurrection entered into a Consent Decree and agreed to perform certain remediation work -
SEMS#303506.

5/16/1994

EE/CA issued for stream sediments in Oregon Gulch - SEMS#316972.

7/1/1995

Action Memorandum issued for PRP-financed removal action at the Oregon Gulch Stream Sediments site -
SEMS#317240.

8/04/1995

Removal Action Completion Report issued - SEMS#322119.

6/1/1997

ROD issued - SEMS#322208.

8/08/1997

O&M Plan and Final Remedial Design Report issued - SEMS#323629.

6/03/1998

Remedial Action Completion Report issued - SEMS#287878.

11/15/1999

Vegetation Monitoring Report issued - SEMS#481036.

12/05/2000

The EPA issued a Notice of Intent to Partially Delete.

2/15/2001

OU10 partially deleted from the NPL - SEMS#100000238.

4/16/2001

ESD issued, clarifying institutional controls - SEMS#1267314.

7/29/2013

B-17

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Table B-15: Chronology of OU11 Events

01 ii

Diilo

California Gulch Superfund site placed on the NPL.

9/08/1983

Investigation study conducted by Colorado Department of Law.

1986

Phase IRI Report issued - SEMS#325440, 308998, 309003.

5/1/1987

Emergency response due to high spring run-off threatening severe erosion of a stretch of the
Arkansas Riverbank.

6/1993

Emergency removal of river tailings - SEMS#478615.

10/28/1993

Two time-critical removal actions to stabilize the embankments of two properties abutting the
Arkansas River - SEMS#2003514, 2003519.

9/1994

Emergency removal of river tailings - SEMS#478617.

11/01/1994

Action Memorandum issued for time-critical removal action - SEMS#322266.

9/15/1997

Amendment to 09/15/1997 Action Memorandum issued - SEMS#323546.

8/04/1998

Action Amendment issued for time-critical removal action issued - SEMS#232091.

6/17/1999

Action Amendment issued for time-critical removal action issued - SEMS#478219.

6/09/2000

Amendment to Action Memorandum dated 06/09/2000 issued - SEMS#478215.

8/11/2000

FS Report issued - SEMS#1049484.

12/1/2004

ROD issued - SEMS#2032941.

9/28/2005

Remedial action started.

9/13/2006

Remedial Work Plan issued - SEMS#1151714.

4/02/2007

Risk/health assessment and risk addendum (risks from mercury) issued - SEMS#1151711.

4/09/2007

Remedial design completed.

9/17/2007

Removal action completed - SEMS#1061008, 1061009, 1061010.

10/26/2007

Remedial action construction started.

6/2008

Monitoring and maintenance started.

7/2009

Construction Completion Report issued - SEMS#1151713.

1/11/2010

Monitoring and Maintenance Plan issued - SEMS#1167694.

3/23/2010

Remedial Action Maintenance Summary issued - SEMS#1283400.

3/16/2011

Remedial Action Report issued - SEMS#1267353.

9/19/2013

Table B-16: Chronology of OU12 Events

()l 12 i:\cnl

I);ik'

EPA emergency workers extended public water supply system lines to residences with private wells.

1986

Preliminary Human Health Risk Assessment issued - SEMS#303951.

12/1/1991

Consent Decree with Asarco Incorporated, Newmont/Resurrection Mining Company, Newmont Mining
Corporation, and the Res-Asarco Joint Venture - SEMS#316074, 303506.

8/25/1994

Baseline Human Health Risk Assessments, Part C issued - SEMS#316598.

4/1/1995

Final Baseline Aquatic Ecological Risk Assessment issued - SEMS#320591.

9/1/1995

Baseline Human Health Risk Assessments, Part A issued - SEMS#319625.

1/2/1996

Baseline Human Health Risk Assessments, Part B issued - SEMS#319626.

1/2/1996

Ecological Risk Assessment for the Terrestrial Ecosystem: Evaluation of Risks to Plants and Herbivores
in the Upper Arkansas Floodplain issued - SEMS#321677.

1/1/1997

Hydrogeological Remedial Investigation Report issued - SEMS#320877.

5/1/1996

Surface Water Remedial Investigation Report issued - SEMS#1077124, 320875.

5/1/1996

Groundwater Baseline Human Health Risk Assessment issued - SEMS#321132.

6/1/1996

Aquatic Biological Assessment Data for the Upper Arkansas River Basin near Leadville, 1995 to 1998 -
SEMS#323620.

9/1/1998

Final Monitoring Plan for Sitewide Groundwater issued - SEMS# 1020443.

11/1/2002

Site Characterization Report for the Upper Arkansas River Basin issued - SEMS#1022097, 1023119,
1052364.

10/31/2002

Preliminary Report on the Biological Data for the Upper Arkansas River issued - SEMS#1022089.

2/1/2003

Draft Interim Remedial Investigation Report (OU12) issued - SEMS#2032904.

5/28/2003

Draft Interim Focused Feasibility Study (OU12) issued - SEMS#2032902.

5/28/2003

A Synopsis of 17 Years Trout Population Biometrics in the Upper Arkansas River issued -
SEMS#2036964.

6/27/2003

B-18

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()l 12 l.\cn(

Addendum issued - Ecological Risk Assessment for the Terrestrial Ecosystem: Evaluation of Risks to
Plants and Herbivores in the Upper Arkansas Flood Plain - SEMS#1048636.

7/1/2003

Restoration Alternatives Report for the Upper Arkansas River Basin issued - SEM #2037490.

12/31/2003

Characterization of Risks to Aquatic Receptors from Mining-Related Contaminants in Upper Arkansas
River Flood Plain issued - SEMS#1052325.

3/17/2004

Aquatic Biological Monitoring Program for the Upper Arkansas River, 1994-2004 - SEMS#1052392.

2/23/2005

OU12 Groundwater/Surface Water Data Evaluation issued - SEMS#1052368.

9/1/2005

Quantitative Exposure-Response Model for Mortality in Brown Trout Fry Exposed to Zinc -
SEMS#1052393.

11/11/2005

Preliminary Evaluation of Potential Site-Specific Zinc and Cadmium Standards for the Upper Arkansas,
Segments 2b and 2c - SEMS#1052370.

9/1/2006

RI completed - SEMS#1052320.

1/1//2007

Human Health Risk Assessment completed.

6/20/2007

FFS completed - SEMS#1096312.

11/1/2007

ROD issued, including TI waiver - SEMS#1102149

9/22/2009

Restoration Plan and Environmental Assessment for the Upper Arkansas River Watershed completed -
SEMS#1293995.

4/14/2010

ROD issued, including TI waiver - SEMS#1102149.

9/22/2010

Environmental covenants placed on Newmont/Resurrection properties - SEMS#1242260, 1242261,
1242262.

7/31/2012 and
10/1/2012

Remedial design completed - SEMS#1558339.

4/29/2015

Action Memorandum for OU 12 issued - SEMS#1772202-R8SDM.

6/7/2016

B-19

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APPENDIX C - SITE BACKGROUND

Sitewide Physical Characteristics and Location

The Site is in the Southern Rocky Mountain Physiographic Province of the United States, which is characterized
by fault-block mountain ranges separated by intermountain valleys. The Site consists of about 18 square miles in
Lake County, about 100 miles southwest of Denver (Figure D-l). It includes the city of Leadville and a section of
the Arkansas River from the confluence of California Gulch downstream to the confluence of Two-Bit Gulch
Creek. Leadville is on the east side of the Arkansas River Valley, at the base of Mount Evans, near the confluence
of Evans Gulch with the Arkansas River. About 2,600 people live in Leadville, according to the 2010 U.S.

Census.

The Site's elevation ranges from 9,300 feet at the confluence of Two-Bit Gulch and the Arkansas River at the
southwestern boundary of the Site to over 12,000 feet near Ball Mountain east of Leadville, Colorado. The
topographic features of Lake County strongly influence the climatic variations in the Leadville area. The elevation
of Leadville is about 10,000 feet above mean sea level. Normal temperatures range from 30°F to 86°F, with an
average minimum temperature of 21,9°F. Average annual precipitation is 18 inches, with the wettest months
being July and August and the driest months being December and January. Summer precipitation is usually
associated with convective showers. The annual peak snowmelt usually occurs in June. The average frost-free
season is 79 days.

Sitewide Land and Resource Use

Land uses at the Site include housing, commercial businesses such as restaurants and shops, and facilities for
recreation, historic tourism, athletics, industrial and mining activities. The zoning districts for the area include
industrial mining, business, recreational and residential districts. The Parkville Water District supplies water to
the majority of homes and businesses in the area.

The Site has been the location of mining, mineral processing and smelting activities that have produced gold,
silver, lead and zinc for more than 130 years. Mining activities in Leadville began in 1859, when gold-bearing
placer deposits were found along California Gulch. Since that time, mining activity was almost continuous,
although there have been production cessations or slowdowns because of economic conditions or labor issues. An
estimated 26 million tons of ore were produced in the Leadville Historic Mining District from 1859 through 1986.
Today, nearly all of the mines within the Site are inactive, and all of the mills and smelters have been either
decommissioned or demolished.

Sitewide History of Contamination

Many mining methods were used at the Site, including placer mining, exposed fissure veins and underground
mining. Waste rock was excavated and left near the mine entrances while metal ores were processed by crushing,
milling and smelting, resulting in the generation of several different types of waste. The types of waste generated
as a result of mining activities are described below:

1. Waste Rock Piles: Waste rock removed from underground workings was placed near mine entrances. This
waste rock often contains elevated levels of heavy metals and sulfide minerals. In the presence of water,
sulfide minerals can generate acid, lowering the pH of the water. This low-pH water promotes the
leaching of heavy metals from the rock and into surface and groundwater.

2. Mill Tailings: At mills on the Site, ores were crushed and separated into metallic concentrates and waste
products by physical processes. Metallic concentrates were then shipped elsewhere or further processed at
a smelter in the area. Waste products (mill tailings) were generally placed in nearby tailings ponds.
Release of contaminants from tailings material can be attributed to seepage from existing tailings deposits
and from additional tailings transported by fluvial processes and deposited along the surface water
channel. Metal contamination in sediments and surface water is the result of tailings pile runoff and seeps
emanating from the toe of some tailings deposits.

C-l

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3. Slag and Other Smelter Wastes: In the smelters, high-grade ores were refined and concentrated into
higher-grade products. Waste products from the smelters include slag flue dust and stack emissions, all
containing heavy metals. Contaminants in smelter stack emissions often commingled with soils as
particulates settled out of the atmosphere. There were 44 known smelters in the district.

4. ARD: Groundwater flooded the mines, bringing oxygen into contact with the pyritic ores. These
materials, when oxidized, break down and alter the sulfide minerals to form ARD water. This low-pH
water leaches heavy metal constituents from rocks and into surface water runoff.

More than 2,000 mine waste piles have been identified on the Site; these are associated with the estimated 26
million tons of ore produced over the history of operations. A few of these waste piles are in residential areas of
Leadville. Contamination of soil and surface water drainage in populated areas occurs throughout the Site. Large
amounts of water are treated by water treatment facilities on site and off site. Mine tailings from the historical
mining activity were also transported downstream via California Gulch to the Arkansas River and deposited in
many locations next to the river. Some contaminated sediments were also transported along irrigation channels
and deposited in fields in the Arkansas River Valley.

The EPA added the Site to the NPL in 1983. The EPA added the Site to the NPL because of concerns about the
impacts of heavy metals in soils and waste rock on humans, and mine drainage on surface waters in California
Gulch and the Arkansas River.

Sitewide Basis for Taking Action

Beginning shortly after site discovery in 1982, private parties, the USGS, and the EPA conducted groundwater
and surface water studies at the Site. The initial Phase I RI Report was complete in May 1987, with subsequent
RI/FSs performed by Woodward-Clyde in 1990 and 1991. The 1987 Phase I RI Report indicated that surface
water in California Gulch exceeded primary drinking water standards for lead and cadmium and that site surface
water contained cadmium, copper, lead and zinc at levels that exceeded water quality criteria. Additionally, soils
at the Site were found to contain elevated levels of arsenic, zinc, lead, copper and cadmium.

BRAs characterized risks to human and ecological receptors at the Site assuming no cleanup has occurred. Risk-
based numerical cleanup goals were also established for the entire populated area as a function of land use. A
summary of site risks and numerical cleanup goals is below.

Under the 1994 Consent Decree, assessment of sitewide surface water and groundwater quality relative to
appropriate performance standards was deferred to OU12. The EPA issued a ROD for OU12 in September 2009;
remedial activities are underway. Although the 1996 BRAs concluded that ingestion of shallow groundwater for
potable purposes would result in future risks to residents above a level of concern, shallow groundwater is not
currently used for drinking water. Therefore, Site risks and associated numerical cleanup goals applicable to OUs
2 through 11 are limited to soils, sediments and mine wastes (solid media).

Several BRAs have been completed for the Site. They are listed below:

1. 1991 Preliminary Human Health Baseline Risk Assessment for the California Gulch National Priority
List (NPL) Site: The presence of elevated levels of heavy metals in soils in and around the residential and
commercial areas of Leadville was discovered during early site investigations. This information informed
the preliminary risk assessment, which indicated that contaminant levels were high enough to be of
potential human health concern. Lead and arsenic were identified as the primary chemicals of potential
human health concern.

2. 1996 Baseline Human Health Risk Assessment for the California Gulch Superfund Site. Part A - Risks to
Residents from Lead: This assessment focused on the risks of lead exposure to young children (ages 0 to
6 years). Because they typically have higher intake rates of environmental media per unit body weight
than adults, young children tend to absorb a higher fraction of ingested lead than adults and they tend to
be more susceptible to some of the adverse effects of lead than adults. The EPA used site-specific inputs

C-2

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to the integrated exposure, uptake and biokinetic model (IEUBK model) along with structural equation
modeling of empirical blood lead and environmental lead data, to assess risk to residents from lead. The
study concluded that residential lead exposure may result in adverse health effects to soil and future
exposure to groundwater.

3. 1996 Baseline Human Health Risk Assessment for the California Gulch Superfund Site. Part B Risks to
Residents from Contaminants other than Lead: This assessment focused on risks to current and future
residents of Leadville from environmental media contaminated with mine-related wastes other than lead.
The assessment adopted a preliminary remediation goal approach to the risk analysis, where a
concentration for each contaminant of potential concern was identified using a specific level of health risk
for each medium. The preliminary remediation goal was then compared to sitewide data to determine if
site concentrations exceed the calculated value. The study concluded that non-lead metals in surface soils
do not pose a significant health risk to residents while future use of groundwater may cause adverse
health effects.

4. 1995 Baseline Human Health Risk Assessment for the California Gulch Superfund Site. Part C: Screening
Level Soil Concentrations for Workers and Recreational Site Visitors Exposed to Lead and Arsenic

1. Baseline Human Health Risk Assessment for the California Gulch Superfund Site. Part C:
Evaluation of Worker Scenario: The BRA evaluated risks to current or future workers in the
commercial and business district of the community. The study focused on the risks associated
with exposure to lead and arsenic in soil and dust through ingestion. The study concluded that
risks to current workers from lead and arsenic are likely to be below a level of concern. The study
further concluded that some uncertainty exists regarding the magnitude of potential future risks as
well as the potential for unacceptable current risks in specific sub-locations within the Site.

2. Baseline Human Health Risk Assessment for the California Gulch Superfund Site. Part C:
Evaluation of Recreational Scenarios: The BRA evaluated risks that environmental
contamination poses to people who engage in recreational activities (e.g., hunting, hiking, bike
riding, and picnicking) in areas in and around the community. This study focused on the risks
associated with lead and arsenic at the Site. The study concluded that average lead levels are
generally below the recreational action level for areas where recreational scenarios are considered
likely.

5. 1995 Final Baseline Aquatic Ecological Risk Assessment for the California Gulch NPL Site: The Aquatic
Ecological Risk Assessment evaluated the impact of mine waste contamination on the aquatic ecosystem
at the Site. The mine wastes in the area are associated with increased heavy metal loading to the surface
water and sediments within the site drainages and the Arkansas River. The study concluded that
discharges of metals from California Gulch continued to result in conditions in the Arkansas River that
were of concern, especially near its confluence with California Gulch.

Human Health Risks

As discussed above, Part B of the Baseline Human Health Risk Assessment concluded that there are no locations
on the Site where antimony, barium, cadmium, beryllium, chromium, copper, mercury, nickel, silver, thallium or
zinc are of significant concern in soils. The risk assessment also concluded that the risk of exceedance is small for
arsenic and manganese and occur only in the most conservative risk calculations. This combined with the
recognition that assumed uptake (bioavailability) of metals used in risk calculations may be higher than actual, led
to the conclusion that non-lead metals in surface soils do not pose a significant health risk to residents. Thus, the
only COC for human health in soil is lead. To evaluate risk, calculations were performed to identify
concentrations (action levels) of lead in soil that were of potential concern. Table 1 summarizes the Site's land
use-based lead remediation goals.

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Table C-l: Land Use-Based Lead Remedial Goals

l.iind I se-li;ised
Kcmcdhilion (io:ils

l.iind I Nc'-I};isc'(l l.oiid Rcnu'diiil (.o;il

Reference'

Recreational

16,00U

BRA Pari C

Worker

6,100-7,700 (plausible action levels)

BRA Part C

Residential

3,500

BRA Part A and OU9 ROD

Notes:

mg/kg = milligrams per kilogram

To identify areas where land use-based remediation goals might be exceeded, the goals were compared to findings
of soil concentration values in previous RIs. Average lead levels over an exposure area are compared to the soil
remediation goal. Occasional measurements of concentrations above the remediation goal do not necessarily
constitute evidence that an area is unsafe.

Review of the prior RIs shows that average lead levels are generally well below the action level of 16,000 mg/kg
for areas where recreational scenarios are considered likely. For the worker scenario, the average lead levels are
mostly below the central tendency range of plausible action levels (6,100 mg/kg to 7,700 mg/kg) for most areas
zoned for commercial land use, with the possible exception of some areas in the historic mining area east of
Leadville and in the vicinity of the former AV Smelter southwest of Leadville.

Although the BRA found that arsenic concentrations in soil posed a negligible risk, soil sampling activities
performed several years later in support of deletion activities identified several isolated areas where arsenic
concentrations exceeded the upper range of plausible action levels for residential land use (120 mg/kg to 340
mg/kg, BRA Part B). The arsenic exceedance occurred where the corresponding lead concentration was below the
residential action level of 3,500 mg/kg. These isolated areas are in outlying, undeveloped portions of OU9
(Residential Populated Areas).

Ecological Receptor Risks

The 1995 Aquatic Ecological Risk Assessment evaluated risks both to terrestrial and aquatic receptors. Terrestrial
receptors included plants that had been irrigated with contaminated surface water and herbivores that had ingested
contaminated plants and soil. Historical irrigation activities resulted in risk associated with both these ecological
receptor pathways, but remedial actions under OU11 have addressed these risks.

The Upper Arkansas River is a suitable habitat for a wide range of aquatic macroinvertebrates (e.g., annelids,
crustaceans, water mites, insects, mollusks and flatworms) and for several species of fish, including four species
of salmonids (brown trout, rainbow trout, cutthroat trout and brook trout), and two species of sucker (i.e., white
sucker and long-nose sucker). In the 1995 Aquatic Ecological Risk Assessment, the EPA established three
assessment endpoints for the Site:

1. Attaining and maintaining a trout population density and diversity below the confluence with California
Gulch within the site boundaries comparable to that observed at reference locations upgradient of the
confluence of California Gulch with the Arkansas River.

2. Maintaining an adequate prey base for trout comparable to that observed in the reference area locations.

3. Maintaining an aquatic community comparable to reference area locations.

Contamination flowing downstream from California Gulch had adversely affected the Upper Arkansas River for
aquatic receptors with impacts most severe at the confluence and dissipating with distance downstream. Initiation
of the Yak Tunnel WTP in 1992 improved water quality conditions within the first two years of operation.
However, metals were still present at levels of concern. Zinc presented the greatest hazard for aquatic receptors,
while levels of cadmium, copper and lead presented lower risks than zinc.

C-4

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Sitewide Initial Response

Prior to the Site's NPL listing, groundwater and surface water studies were conducted by private parties, the
USGS and the EPA.

The contaminated drainage from the Yak Tunnel was identified as the most pressing problem at the Site. It was
thus the first to be addressed. The Yak Tunnel remedy - capturing and treating the Yak Tunnel drainage - was
designated as OU1. The EPA signed the ROD for OU1 in 1988 and modified it by amendment in 1989. An ESD
was signed in 1991.

In 1994, a Consent Decree was executed between the EPA, the State and the following PRPs:

1. ASARCO Incorporated (ASARCO).

2. Joint Venture between ASARCO and Newmont/Resurrection Mining Company (Res-ASARCO).

3. Newmont/Resurrection Mining Company and its parent, Newmont Mining Company
(Newmont/Resurrection).

The 1994 Consent Decree specified that RODs selecting response actions pertaining to source remediation would
be selected before a ROD would be issued for OU12 (Sitewide Water Quality). As a result, the remedies for OU2
through OU11 were selected prior to selecting the remedy for OU12. The EPA issued the OU12 ROD to address
sitewide surface water and groundwater contamination in 2009. Water quality data are collected on an ongoing
basis.

OU8: Complete OU Background

OU8, also known as Lower California Gulch, is defined by the 500-year floodplain of California Gulch from
immediately below the boundary of the Yak Tunnel WTP (OU1) to the point of confluence of California Gulch
with the Arkansas River (Figure D-9). OU8 also includes the CZL Tailing Impoundment outside the 500-year
floodplain. OU8 is about 97 acres in size and 4.3 miles long. OU8 borders portions of several other OUs,
including OU1 (Yak Tunnel WTP), OU2 (Malta Gulch Fluvial Tailing/Leadville Corp. Mill/Malta Gulch Tailing
Impoundments), OU3 (D&RGW slag piles/Railroad Easement/Railroad Yard), OU5 (ASARCO
Smelters/Slag/Mill Sites), OU7 (Apache Tailing Impoundments), OU9 (Residential Populated Areas), and OU10
(Oregon Gulch). Lower California Gulch receives runoff and water from tributaries that drain all or portions of
these other OUs. Lower California Gulch also receives tributary water from upper California Gulch and Stray
Horse Gulch via Starr Ditch that drain areas of OU4 (Upper California Gulch) and OU6 (Starr Ditch/Penrose
Dump/Stray Horse Gulch). The land area in OU8 consists mostly of private property. No residences are located in
OU8. Highway bridges, road crossings and culverts are located in the 500-year floodplain of Lower California
Gulch. Lower California Gulch roughly parallels U.S. Highway 24.

Appendix D contains detailed maps for OU8 (Appendix D), FTS 1 and FTS 2, and the CZL Tailing
Impoundment; FTS 3; FTS 8 and non-residential soils; and FTS 6, the Gaw Waste Rock Pile and non-residential
soils. The land surrounding and within OU8 is zoned for industrial mining and business uses.

The area composing OU8 was originally a placer gold mining district, starting with the discovery of gold in
California Gulch in 1860. When the placer deposits began to be exhausted, underground mining was started to
extract gold, silver, lead and zinc ores. Ore was subsequently crushed and separated into metallic concentrates at
nearby mills, with mill tailings slurried into tailings impoundments. Fluvial deposits of tailings occurred as
tailings was complete from impoundments. Waste rock from underground mining was frequently dumped near
mine shafts, as was the case with the Gaw Waste Rock Pile.

Tailings impoundments at the Site have resulted in fluvial deposits of tailings being transported by surface flows
and deposited at specific locations in OU8. Likewise, during high flow events, stream sediments originating from
source areas primarily upstream of OU8 are transported by California Gulch and associated tributaries into and
within OU8. The stream sediment in Lower California Gulch was contaminated with mine wastes and associated
metals transported from upstream sources. The soluble metals contained in runoff have contributed to the

C-5

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contamination of surface water and sediments. Additionally, waste rock from underground mining was frequently
dumped near mineshafts within the Site and has added to the contamination.

The CZL Tailing Impoundment is the only tailings impoundment identified in OU8. The CZL Site was an
operating flotation mill that processed zinc-lead ores sporadically between 1925 and 1940. The CZL Tailing
Impoundment is located about 1 mile west of Leadville and immediately north of Stringtown. The CZL Tailing
Impoundment at the Site of the flotation mill operation covered about 1.6 acres, at an average depth of 7 feet. The
CZL Tailing Impoundment contained an estimated 17,000 cubic yards of tailings.

The Gaw Waste Rock Pile is located upstream of the Apache Tailing Impoundment (OU7) within OU8. The Gaw
Waste Rock Pile represents the only deposit of waste rock identified within OU8.

Five fluvial tailings sites within OU8 were found to have elevated levels of contamination. FTS1, covering about
3.4 acres, is adjacent to the La Plata Slag Pile (part of OU3) and extends downstream in a westerly direction to a
point about 1,000 feet upgradient of the CZL Tailing Impoundments. California Gulch flows through the tailings
and the gulch has cut a channel through the fluvial deposits. The fine to coarse grained tailings and
alluvial/tailings materials ranged from 1-6 feet in depth.

FTS2 lies 200 feet downstream of FTS1 and covers an estimated 3.2 acres. The fluvial tailings material in FTS2 is
generally light brown-to-brown clay silts and sands overlying light brown silt that contains cobbles and sand.

FTS3 is immediately downstream of Lake County Road 6 on California Gulch and covers about 4.8 acres. The
flow of California Gulch through FTS3 is split into a north and south channel, with most of the flow occurring in
the North Channel.

FTS6 is located on California Gulch between the Yak Tunnel Treatment Plant Surge Pond embankment and the
Apache Tailing Impoundments, and covers about 4.2 acres. Part of the Gaw Waste Rock Pile is also in FTS6. The
pile covers about a half-acre and has an estimated volume of 7,500 cubic yards.

FTS8 extends from the AV Slag Pile (part of OU3) to a point about 6,500 feet downstream to the confluence of
California Gulch with the Arkansas River. FTS8 is a series of small discontinuous tailings deposits with a total
estimated area of 115 acres. The OU8 ROD addresses about 45 acres of fluvial tailings that lie within the
floodplain boundaries of the portion of FTS8.

Stream sediments were identified as a potential contaminant source in the Site's SFS. The primary concerns were
loose and erodible sediments that could be resuspended and carried downstream. The studies estimated that there
were about 4,500 cubic yards of stream sediments of potential concern.

OU9: Complete History of Initial Responses

The State, the EPA and certain PRPs have conducted various studies and investigations to evaluate the nature and
extent of contamination at the Site. In 1991, remedial investigations began for several areas at the Site, including
mine waste rock piles, tailings disposal areas, surface water and aquatics, groundwater, smelter sites,
residential/populated area soils, slag piles and terrestrial studies. These studies found lead in soils to be the
primary COC in OU9.

ASARCO Incorporated and many community members argued that there are numerous environmental sources of
lead in residential areas of Leadville, including mining-related sources such tailings and mine waste piles and
other household sources such as lead-containing paint on interior and exterior surfaces of homes and lead found in
food, water and residential soils. As recommended by ASARCO Incorporated and the community, the interim
response was designed to reduce overall lead-related risk to children in Leadville, including responses that

C-6

-------
address sources that would not normally be remediated under CERCLA authorities. As part of the 1994 Consent
Decree with the EPA and the State, ASARCO Incorporated agreed to undertake actions to address all sources of
lead in lieu of soil removal only at each residence. To determine the effectiveness of the actions, the level of lead
in children's blood was voluntarily monitored and performance standards in relation to concentrations of lead in
the blood of children were established.

In 1995, ASARCO Incorporated began implementing the Lead Risk Reduction Program, more commonly known
as the Kids First program. ASARCO Incorporated agreed to operate the Kids First program as an interim response
action until the EPA selected a remedy for OU9. The purpose of the program, a risk reduction response program
based on voluntary participation, was to provide information to the community and reduce children's exposure to
a variety of sources of lead.

The Kids First program consisted of a variety of services and remedial response activities designed to:

1. Gather information from the community.

2. Identify residences for which response actions are needed.

3. Plan and prioritize the risk reduction responses for these residences.

4. Perform the risk reduction responses.

5. Provide additional information and services to the community.

Initially, the Kids First program targeted residences where sample soil lead levels were found above 3,500 mg/kg,
because the EPA established an interim response level of 3,500 mg/kg of lead for Leadville residential soils. The
basis for this value is presented in the 1994 Consent Decree, along with a discussion of trigger criteria for other
significant environmental media (dust, paint and water). These trigger criteria were used by the Kids First Work
Group to identify and prioritize locations for response actions.

Residences with children that had blood lead levels greater than 10 (ig/dL, measured during the 1991 blood lead
study or any subsequent blood lead monitoring, were targeted for priority response in the program.

Information used in the evaluation of residences and the selection of appropriate response actions (if needed)
came from a variety of sources. Response programs included in the Kids First program were:

1. The blood lead monitoring program by Lake County Health Department.

2. A lead information hotline and a door-to-door survey within priority exposure areas.

3. Additional sampling and property assessment.

Lake County Health Department managed the voluntary blood lead monitoring program, which was funded by
ASARCO Incorporated. The blood lead monitoring program was a key component of the interim response
program. Ongoing blood lead monitoring was provided upon request for children below the age of 72 months (six
years) and for pregnant/nursing women. The data were used as one means of identifying individuals who had
blood lead levels greater than 10 (ig/dL. The data were also used in the finalization of the BRA.

All residents who responded via the hotline, coming into Lake County Health Department or completing door-to-
door survelys received information about the program. The responses resulted in the need for more sampling of
soils, paint, dust, water, and blood-lead levels. Additional sampling was conducted if a residence:

1. Was located in the 3,500 mg/kg lead soils priority area.

2. Had a child with a blood-lead level greater than 10 (ig/dL.

3. Had a pregnant or nursing woman in the home.

4. Was known to have paint in poor condition.

5. Was known to have another possible lead source (e.g., lead pipes, certain hobbies).

6. Was requested by a resident not within the designated priority risk area.

C-7

-------
The first year, remediations were performed at 37 properties in accordance with Action Memoranda prepared for
each property. The Kids First Work Group developed and approved all action and no-action determinations. The
property owners consented on all investigations and remediations.

The Kids First program integrated a variety of lead toxicity intervention and abatement methods. Additionally, the
program addressed reducing children's exposure to lead in soils, dust-containing lead in residences, and additional
lead sources such as paint and tap water. For these reasons, the Kids First program was presented as an alternative
in the FS when it was revised and renamed the LCCHP.

The remediation of OU9 was divided into many separate removal actions as well as remedial actions. Table C-2
summarizes these actions:

Table C-2: Response Actions for OU9

AiVii

1 iiiu'lViiiiH'

Tj |)c of Ad ion

Kciik'(I> Implemented

Private well

5/29/1986

N/A

Water connection to the Parkville Water
District provided.

Kids First program -
individual residences

10/16/1995 to
04/21/2000

Time-critical removal
actions

Addressed contaminated media associated
with residential properties.

Waste rock piles

08/15/1996 to
7/31/2001

Time-critical removal
actions

Addressed elevated levels of contaminants in
mine waste rock piles.

Morning Star day
care

Fall 2005

Time-critical removal
actions

Addressed contaminated media associated
with day care.

LCCHP - multiple
residences

2000 to 2011

Remedial action

Addressed contaminated media associated
with residential properties.

Removal actions under the Kids First program started on October 16, 1995. The LCCHP described in the ROD
took the place of the Kids First program. An EE/CA was prepared in 1995 to evaluate removal action alternatives
for the 38 mine waste piles and one control pile, for a total of 39 piles identified in the populated areas within
OU9. During the RI, eight of the 38 piles were found to be stockpiles of construction materials or to not pose a
threat to human health or the environment. However, one pile representing this group was evaluated with the
remaining 30 piles as a control to confirm the EE/CA's findings. An Action Memorandum issued by the EPA in
August 1996 selected a non-time-critical removal action requiring the removal of 14 piles with surface lead
concentrations greater than 3,500 mg/kg. Implementation of this removal action began in 1997, with the removal
of four mine waste piles. The removal of the remaining 10 mine waste piles finished in 1999. The material
excavated from the mine waste piles was taken to a repository for disposal and the excavated area was
revegetated.

C-8

-------
Figure D-l: Site Vicinity

APPENDIX D - SITE MAPS

D-l

-------
Figure D-2

OUl Map

	mk

proximate Site Boundary |
^ OU1

Bedrock Monitoring Well
1 Yak Tunnel

Disclaimer: This map and any boundary lines within the map are approximate and subject to
change. The map is not a survey. The map is for informational purposes only regarding the EPA's
response actions at the Site. Sources: Esri, HERE, Garmin, SafeGraph, GeoTechnologies, Inc,
METI/NASA, USGS, Bureau of Land Management, EPA, NPS, US Census Bureau, USDA,
Earthstar Geographies, Maxar and the 2012 FYR.

^Skeo

Last Modified: 6/3/2022

1,000 2,000 3,000 4,000 5,000 Feet

D-2

-------
N California Gulch Superfund Site

A City of Leadville, Lake County, Colorado

Disclaimer: This map and any boundary lines within the map are approximate and subject to
change. The map is not a survey. The map is for informational purposes only regarding the EPA's
response actions at the Site. Sources: Earthstar Geographies, Esrf Community Maps
Contributors, Esri. HERE, Garmin, SafeGraph, GeoTechnologies, Inc, METI/NASA, USGS,
Bureau of Land Management, EPA, NPS. US Census Bureau, USDA, Maxarand the 2012 FYR.

Last Modified: 6/3/2022

Figure D-3: OU2 Map

Approximate Site Boundary

VJ^jMalta Gulcfi^O
Tailing Impoundments

Malta Tailing
Impoundment

Lower
Malta Gulch

fued Stream

D-3

-------
N California Gulch Superfund Site

A City of Leadville, Lake County, Colorado

Disclaimer: This map and any boundary lines within the map are approximate and subject to
change. The map is not a survey. The map is for informational purposes only regarding the EPA's
response actions at the Site. Sources: Esri, HERE, Garmin. SafeGraph. GeoTechnologies, Inc.
METI/NASA, USGS, Bureau of Land Management, EPA, NPS, US Census Bureau, USDA,
Earthstar Geographies, Maxar and the 2012 FYR.

Last Modified: 7/1/2022

Figure D-4: OU3 Map

Rail Yard/
Poverty Flats

Mineral Belt
Trail



Harrison Avenue
Slag Piles

La Plata
Slag Pile

Arkansas Valley
Slag Pile

Approximate Site Boundary
OU3



D-4

-------
Figure D-5: OU4 Map

	 Approximate Site Boundary

CQ. OU4

N	California Gulch Superfund Site

A	City of Leadville, Lake County, Colorado

A	i	1	1

^	0	2.000	4,000 Feet

Disclaimer: This map and any boundary lines within the map are approximate and subject to
change. The map is not a survey. The map is for informational purposes only regarding the EPA's
response actions at the Site. Sources: Esri, HERE. Garmin, SafeGraph. GeoTechnologies, Inc,
METI/NASA, USGS, Bureau of Land Management, EPA, NPS, US Census Bureau. USDA,
Earthstar Geographies. Maxar and the 2012 FYR.

^Skeo

Last Modified: 6/3/2022

D-5

-------
Disclaimer: This map and any boundary lines within the map are approximate and subject to
change. The map is not a survey. The map is for informational purposes only regarding the EPA's
response actions at the Site. Sources: Esrl, HERE, Garmin, SafeGraph, GeoTechnoiogies, Inc,
METI/NASA, USGS, Bureau of Land Management, EPA, NPS, US Census Bureau, USDA,
Earthstar Geographies, Maxar and the 2012 FYR.

n California Gulch Superfund Site

A City of Leadville, Lake County, Colorado

Last Modified: 7/1/2022

Figure D-6: OU5 Map

Approximate Site Boundary
OU5

Elgin Smelter
Site

Western Zinc
Smelter Site

Colorado
Zinc-Lead Mill

Arkansas Valley
Smelter

California

Grant/Union
Smelter Site

Arkansas Valley South
Hillslide Slag Pile

D-6

-------
n California Gulch Superfund Site

A City of Leadville, Lake County, Colorado

Disclaimer: This map and any boundary lines within the map are approximate and subject to
change. The map is not a survey. The map is for informational purposes only regarding the EPA's
response actions at the Site. Sources: Esri, HERE, Garmin, SafeGraph, GeoTechnologies, Inc,
METI/NASA, USGS, Bureau of Land Management, EPA, NPS. US Census Bureau, USDA,
Earthstar Geographies, Maxar and the 2012 FYR.

Last Modified: 6/3/2022

Figure D-7: OU6 Map

Approximate Site Boundary
OU6

.LMDT Pump
Station

VRobert /

Emmet Shaft Mikados Pond

Marian-Pond;



'Greenback
Po"nciS<

Yak Tunnel

D-7

-------
Figure D-8: OU7 Map

]i?eaqViillel

Approximate Site Boundary



Starr Ditch.



Apache Tailing
Impoundment

cs&?

nXfiltln

N	California Gulch Superfund Site

A	City of Leadville, Lake County, Colorado

^	i	1	1

^	n	«;nn	^ nnn Con

Disclaimer: This map and any boundary lines within the map are approximate and subject to
change. The map Is not a survey. The map is for informational purposes only regarding the EPA's
response actions at the Site. Sources: Esri Community Maps Contributors. © OpenStreetMap,
Microsoft, Esri, HERE. Garmin, SafeGraph, GeoTechnologies, Inc, METI/NASA, USGS, Bureau of
Land Management, EPA, NPS, US Census Bureau. USDA, Earthstar Geographies, Maxar and
the 2012 FYR.

4^ Skeo

Last Modified: 7/1/2022

D-8

-------
N California Gulch Superfund Site

A City of Leadville, Lake County, Colorado

Disclaimer: This map and any boundary lines within the map are approximate and subject to
change. The map is not a survey. The map is for informational purposes only regarding the EPA's
response actions at the Site. Sources: Esrl, HERE, Garmln. SafeGraph, GeoTechnologies, Inc,
METI/NASA, USGS, Bureau of Land Management, EPA, NPS, US Census Bureau, USDA,
Earthstar Geographies. Maxarand the 2012 FYR.

Last Modified: 6/30/2022

Figure D-9: OU8 Map



California Gulch

Approximate Site Boundary
OU8

D-9

-------
COliORADO ZINC-LEAD
TAItTNa IMPOUNDMENT

YAK TUNNEL
TREATMENT PLANT

Figure D-10: Ol 8 Details

Gaw Waste Rock/FTS-6

SUPERFUND
SITE BOUNDARY

Source: Final Engineering Evaluation/Cost Analysis - Colorado Zinc-Lead Tailing Area within Lower California Gulch - OU8. California Gulch Superfund Site. July
1995.

D-10

-------
N California Gulch Superfund Site

A City of Leadville, Lake County, Colorado

Disclaimer: This map and any boundary lines within the map are approximate and subject to
change. The map is not a survey. The map is for informational puiposes only regarding the EPA's
response actions at the Site. Sources: Esri. HERE, Garmin, SafeGraph, GeoTechnologies, Inc,
METI/NASA, USGS. Bureau of Land Management, EPA, NPS, USDA. Earthstar Geographies,
Maxar and the 2012 FYR.

Last Modified: 6/30/2022

Figure D-ll: OU9 Map

'c.Hiforn/i

Approximate Site Boundary
OU9

D-ll

-------
Figure D-12: OU1G Map

N California Gulch Superfund Site

A City of Leadville, Lake County, Colorado

Disclaimer: This map and any boundary lines within the map are approximate and subject to
change. The map is not a survey The map is for informational purposes only regarding the EPA's
response actions at the Site. Sources: Earthstar Geographies, Esri Community Maps
Contributors, Esri, HERE, Garmin, SafeGraph, GeoTechnologies, Inc, METI/NASA. USGS.
Bureau of Land Management EPA, NFS, US Census Bureau. USDA. Maxar and the 2012 FYR.

Last Modified: 7/1/2022

Approximate Site Boundary
OU10

D-12

-------
Figure D-13: OU11 Map

Disclaimer: This map and any boundary lines within the map are
approximate and subject to change. The map is not a survey. The map is
for informational purposes only regarding the EPA's response actions at
the Site. Sources: Esri. HERE, Garmin. SafeGraph, GeoTechnologies,
Inc. METI/NASA, USGS, Bureau of Land Management, EPA, NPS,
USD A, Earthstar Geographies and the 2012 FYR.

California Gulch Superfund Site

City of Leadville, Lake County, Colorado

Last Modified: 7/1/2022

rmmmm

Approximate Site Boundary
OU11

D-13

-------
APPENDIX E - PRESS NOTICE

Pubished in the Herald Democrat May 12, 2022

The U.S. Environmental Protection Agency,. Region
i Announces the Sixth Five-Year Review for the
California Gulch Superfund Site in Lake County.
Colorado

The U.5, Environmerttal Protection Agency IEPA], in
cooperation with the State of Colorado, is conducting the
sixth *ve-yec" revie-v, of tfe Cci'c-nc Gulci Suoe-fjrd
Site ir Lake Count) Cg crocx F.ve-veo* "eviews provide an
opportunity to evaluate the implementation and performance
of a remedy to determine whether it rewire protective- of
human health and the envKonment The sixth five-year r»iew
wilt be completed in 3022.

"lie Si:- :c "zei cdcu: '8 -xaire ".Is: ir _a68&

Email: loeferJfrKia$epa.gDv

Di.e to Cow d- IS i" e most current site infwimjt™ is
onif ova:Sable on ine at

httpsij\/«*epa.gcw/supe-ri«id/colifoiTiio-giich

Un ted States
hivironmenta Protuct on
/VjiflK v

E-l

-------
APPENDIX F - SITE INSPECTION CHECKLIST

FIVE-YEAR REVIEW SITE INSPECTION CHECKLIST

I. SITE INFORMATION

Site Name: California Gulch

Date of Inspection: Junc_j_6^2022

Location and Region: Leadville, CO Region 8

EPA ID: COD980717938

Agency, Office or Company Leading the Five-Year
Review: EPA

Weather/Temperature: 50 °F. sunny

~ Monitored natural attenuation

~ Groundwater containment

~ Vertical barrier walls

Remedy Includes: (check all that apply)

1X1 Landfill cover/containment
1X1 Access controls
1X1 Institutional controls
~ Groundwater pump and treatment
1X1 Surface water collection and treatment

1X1 Other: Soil and mine waste excavation with consolidation, treating soils with amendments,
groundwater treatment in a treatment plant, tunnel plugging, encapsulation of slag. Retaining walls
along access roads to the waste piles of OU6 including cribbing and caging to prevent erosion.

Attachments: CD Inspection team roster attached CD Site map attached

II. INTERVIEWS (check all that apply)

1. O&M Site Manager Devon Horntvedt and

William Santos Title

representing

Newmont/Resurrection -
QUI. 4. 8 and 10 and
CDPHE for remaining
OUs
Name

Interviewed ~ at site ~ at office ~ by phone Phone: _
Problems, suggestions ~ Report attached:

Date

2. O&M Staff

Name

Interviewed ~ at site ~ at office ~ by phone
Problems/suggestions ~ Report attached:

Title
Phone:

Date

3. Local Regulatory Authorities and Response Agencies (i.e., state and tribal offices, emergency
response office, police department, office of public health or environmental health, zoning office,
recorder of deeds, or other city and county offices). Fill in all that apply.

Agency CDPHE
Contact Kyle Sandor
Name

Problems/suggestions ~ Report attached:.

Project

Manager

Title

Date

Phone No.

Agency.
Contact

Name

Title

Date

Phone No.

Problems/suggestions ~ Report attached:.

Agency.
Contact

F-l

-------


Name Title
Problems/sussestions PI Reoort attached:

Date

Phone No.



Asencv
Contact

Name Title
Problems/sussestions PI Reoort attached:

Date

Phone No.



Asencv
Contact

Name Title
Problems/sussestions |~~| Report attached:

Date

Phone No.

4.

Other Interviews (optional) PI Report attached:









III. ON-SITE DOCUMENTS AND RECORDS VERIFIED (check all that apply)

1.

O&M Documents







1X1 O&M manual ^ Readily available

1X1 Up to date

~ n/a



1X1 As-built drawings £3 Readily available

1X1 Up to date

~ n/a



1X1 Maintenance logs ^ Readily available

1X1 Up to date

~ n/a



Remarks: The Yak Tunnel WTP (OU1) has conies of all O&M documents



2.

Site-Specific Health and Safety Plan

1X1 Readily available

1X1 Up to date CD N/A



1X1 Contingency plan/emergency response plan

1X1 Readily available

IXl Up to date |_| N/A



Remarks:





3.

O&M and OSHA Training Records

Remarks:

1X1 Readily available

1X1 Up to date EH N/A

4.

Permits and Service Agreements







~ Air discharge permit

1 1 Readily available

EH Up to date ^ N/A



1X1 Effluent discharge

1X1 Readily available

1X1 Up to date LJ N/A



~ Waste disposal, POTW

~ Readily available

EH Up to date ^ N/A



PI Other oermits:

~ Readily available

EH Up to date ^ N/A



Remarks: OU1 one rates accordins to the 2008 Consent Decree reauirements: NPDES data are readilv



available for the Yak WTP discharse.





5.

Gas Generation Records

Remarks:

~ Readily available

EH Up to date ^ N/A

6.

Settlement Monument Records ^ Readily available EH Up to date EH N/A
Remarks: Waste oilcs (e.s.. consolidated soil, sediment, tailinss and waste rock) are monitored for



settlement and erosion accordins to the O&M olans.



7.

Groundwater Monitoring Records

1X1 Readily available

IXl Up to date EH N/A



Remarks: Sitewide sroundwater monitorins results are included in the OU 12 Annual Reoort.

8.

Leachate Extraction Records

~ Readily available

EH Up to date ^ N/A

F-2

-------
Remarks:

9. Discharge Compliance Records



~ Air EH Readily available EH Up to date N/A

1X1 Water (effluent) [XI Readily available MUp to date EH N/A

Remarks: OU1 discharge is monitored to measure compliance with limits set in the 2008 Consent

Decree.

10. Daily Access/Security Logs £3 Readily available ^ Up to date EH N/A
Remarks: Access is monitored and controlled at OU1. The MGTI Dortion of OU2 is fenced and

includes sisnase reeardine the presence of soil contamination. Several OUs reauired fencins with

warnins sisns (e.s.. OU6 waste oilc oonds. OU7 impoundment. OU9 soil repository. OU10 dluhd

house). Portions of OU2. OU3. OU8 and OU9 do not reauire access restrictions while other areas are

not fenced but are oostcd with warnine sisns (OU4. OU5. OU11).



IV. O&M COSTS

1. O&M Organization



I~1 State in-house

1X1 Contractor for state (OU2, 3, 5, 6, 7, 9, 11 and 12)

1 1 PRP in-house

1X1 Contractor for PRP (OU1, 4, 8 and 10)

I~1 Federal facility in-house

EH Contractor for Federal facility

n



2. O&M Cost Records



I~1 Readily available

EH Up to date

1X1 Funding mechanism/agreement

in place Unavailable

Orisinal O&M cost estimate:

EH Breakdown attached

Total annual cost by year for review period if available

From: To:

n Breakdown attached

Date Date

Total cost

From: To:

n Breakdown attached

Date Date

Total cost

From: To:

n Breakdown attached

Date Date

Total cost

From: To:

n Breakdown attached

Date Date

Total cost

From: To:

n Breakdown attached

Date Date

Total cost

3. Unanticipated or Unusually High O&M Costs during Review Period

Describe costs and reasons:

V. ACCESS AND INSTITUTIONAL CONTROLS ~ Applicable ~ N/A

A. Fencing

1. Fencing Damaged EH Location shown on site map EH Gates secured EH N/A
Remarks: Fencins is dresent at the Yak Tunnel WTP on OU 1 and around a few other

F-3

-------
areas, such as the leachate collection ponds in OU6. the capped OU7 Apache Tailing Impoundments, the
soil repository for OU9 and the pump house at QUIP. Fencing is generally in good condition and access
gates are secured when authorized persons are not present. Fencing required repair in OU6 around the
Robert Emmet shaft and Marion Pond which is planned to be repaired as part of the routine O&M
conducted by CDPHE contractors. Fencing was not warranted at OU2. OU3. OU4. OU5 and OU8.

B. Other Access Restrictions

1. Signs and Other Security Measures ~ Location shown on site map ~ N/A

Remarks: Signs are present at OU1 and along stretches of OUs 4. 6 and 9 in locations near the Mineral
Belt Trail. This recreational path loops through the Site and includes several educational signs about the
Site history as well as current remedial actions (i.e.. the capping pilot study area on 01161. The ponds
containing ARD are fenced and no trespassing signs are posted. 0U7 and QUIP were also
Fenced and w arning signs posted.

C. Institutional Controls (ICs)

1. Implementation and Enforcement

Site conditions imply ICs not properly implemented ~ Yes |EI No ~ N/A

Site conditions imply ICs not being fully enforced ~ Yes |EI No ~ N/A

Type of monitoring (e.g., self-reporting, drive by): The institutional controls are enforced through the
issuance of building permites bv the citv and county.

Frequency: As building permits are requested

Responsible party/agency: Lake County and the citv of Leadville

Contact

Name Title

Date

Phone no.

Reporting is up to date

I~1 Yes

~ No

|E1 N/A

Reports are verified by the lead agency

I~1 Yes

~ No

|E1 N/A

Specific requirements in deed or decision documents have been met

|EI Yes

~ No

~ n/a

Violations have been reported

I~1 Yes

|E|No

~ n/a

Other problems or suggestions: ~ Report attached

Adequacy ~ ICs are adequate ICs are inadequate ~ N/A

Remarks: Institutional controls have been fully implemented for 10 of the 12 OUs. 0U6 mav require more
institutional controls once remediation is complete. The EPA is working with CDPHE and private
landowners to implement institutional controls for 0U11.

General

Vandalism/Trespassing ~ Location shown on site map ^ No vandalism evident

Remarks: Trespassing has reportedly occurred in 0U4 and 0U6. bv people exploring the area for
prospecting despite warning signs posted of contamination. The local police department has been tasked
with conducting routine visits at these areas to enforce the no trespassing laws.

Land Use Changes On Site ~ N/A

Remarks: Within 0U3. some residential development is occurring and. prior to development, the mine
waste was excavated and taken to the 0U6 repository for disposal.

Land Use Changes Off Site ^ N/A

Remarks:

VI. GENERAL SITE CONDITIONS

Roads Applicable ~ N/A

F-4

-------
1.

Roads Damaged ~ Location shown on site map ~ Roads adequate ^ N/A
Remarks:

Other Site Conditions

Remarks:

VII. LANDFILL COVERS ^Applicable ~ N/A

Landfill Surface

Settlement (low spots) ~ Location shown on site map ^ Settlement not evident

Area extent: Depth:

Remarks: The covers refer to the rock or veeetated soil covers on the minine waste oilcs. former
tailines impoundments. fluvial tailines sites alone the California Gulch and tailines alone the
Arkansas River.

Cracks Q Location shown on site map Cracking not evident

Leneths: Widths: Depths:

Remarks:

Erosion Q Location shown on site map Erosion not evident

Area extent: Depth:

Remarks:

Holes ~ Location shown on site map £3 Holes not evident

Area extent: Depth:

Remarks:

Vegetative Cover Q Grass ^ Cover properly established

1 1 No signs of stress ~ Trees/shrubs (indicate size and locations on a diagram)

Remarks: Veeetative cover includes soecies that can erow at altitude. Occasionally, the cover reauires
some maintenance where localized barren areas reauire reveeetation. as observed at OU7 and OUIO.
However, these areas have been identified durine annual inspections and the O&M contractor is
addressine these areas durine the erowine season.

Alternative Cover (e.g., armored rock, concrete) Q N/A

Remarks: A variety of covers are beine used on the waste oilcs. Thev include armored rock, eravel
and concrete.

Bulges ~ Location shown on site map £3 Bulges not evident

Area extent: Height:

Remarks:

Wet Areas/Water Damage ^ Wet areas/water damage not evident

r~l Wet areas PI Location shown on site man Area extent:

I"! Pondine PI Location shown on site man Area extent:

PI Sccds I-! Location shown on site man Area extent:

PI Soft suberade I-! Location shown on site man Area extent:

Remarks: Overflow from waste oilc oonds in OU6 is routed to the Robert Emmet area, which then
subseauentlv is directed to the LMDT for treatment. However, for the oast four vears. water levels
have remained low in the waste rock oilc oonds. so overflow has not been a concern. Water levels in
donds were well below the berms.

F-5

-------
9.

Slope Instability Q Slides
1X1 No evidence of slope instability
Area extent:

Remarks:

~ Location shown on site map

Benches ^ Applicable ~ N/A

(Horizontally constructed mounds of earth placed across a steep landfill side slope to interrupt the slope in
order to slow down the velocity of surface runoff and intercept and convey the runoff to a lined channel.)

Flows Bypass Bench Q Location shown on site map Q N/A or okay

Remarks: Several of the waste covers include benches to slow down the velocity of surface runoff and

convev the runoff to the waste oilc oonds in OU6.

Bench Breached Q Location shown on site map
Remarks:

1X1 N/A or okay

Bench Overtopped EH Location shown on site map
Remarks:

1X1 N/A or okay

Letdown Channels ^ Applicable ~ N/A

(Channel lined with erosion control mats, riprap, grout bags or gabions that descend down the steep side
slope of the cover and will allow the runoff water collected by the benches to move off of the landfill
cover without creating erosion gullies.)

Settlement (Low spots) ~ Location shown on site map

1X1 No evidence of settlement

Area extent:

Depth:

Remarks:

Material Degradation ~ Location shown on site map

1X1 No evidence of degradation

Material tvpe:

Area extent:

Remarks:

Erosion Q Location shown on site map

1X1 No evidence of erosion

Area extent:

Depth:

Remarks:

Undercutting ~ Location shown on site map

1X1 No evidence of undercutting

Area extent:

Deoth:

Remarks:

Obstructions Tvoe:

I-! Location shown on site mat) Area extent:

Size:

Remarks:

1X1 No obstructions

Excessive Vegetative Growth Tydc:
1X1 No evidence of excessive growth
1 1 Vegetation in channels does not obstruct flow
I-! Location shown on site mat) Area extent:

F-6

-------
Remarks:

D.

Cover Penetrations ^ Applicable ~ N/A



1

Gas Vents Q Active Q Passive



1 1 Properly secured/locked Q Functioning Q Routinely sampled

1 1 Good condition



1 1 Evidence of leakage at penetration Q Needs maintenance

[El n/a



Remarks:



2

Gas Monitoring Probes





1 1 Properly secured/locked Q Functioning Q Routinely sampled

1 1 Good condition



1 1 Evidence of leakage at penetration Q Needs maintenance

IK|n/a



Remarks:



3

Monitoring Wells (within surface area of landfill)





153 Properly secured/locked ^ Functioning ^ Routinely sampled

E3 Good condition



1 1 Evidence of leakage at penetration ~ Needs maintenance

~ n/a



Remarks: Wells were identified in and adiacent to covered waste oilcs and tailines impoundments and



were Droocrlv labeled and locked.



4

Extraction Wells Leachate





1 1 Properly secured/locked ~ Functioning ~ Routinely sampled

1 1 Good condition



1 1 Evidence of leakage at penetration Q Needs maintenance

£3 N/A



Remarks:



5

Settlement Monuments Q Located Q Routinely surveyed

[21 N/A



Remarks:



E.

Gas Collection and Treatment ~ Applicable ^ N/A



1.

Gas Treatment Facilities





1 1 Flaring Q Thermal destruction

1 1 Collection for reuse



1 1 Good condition Q Needs maintenance





Remarks:



2

Gas Collection Wells, Manifolds and Piping





1 1 Good condition Q Needs maintenance





Remarks:



3

Gas Monitoring Facilities (e.g., gas monitoring of adjacent homes or buildings)



1 1 Good condition Q Needs maintenance ~ N/A





Remarks:



F.

Cover Drainage Layer ^ Applicable ~ N/A



1

Outlet Pipes Inspected ^Functioning Q N/A





Remarks: Abandoned piping was observed under a road in OU6. It will be addressed as part of the



routine O&M activities.



2

Outlet Rock Inspected ^ Functioning Q N/A



F-7

-------
Remarks: Manv of the diversion ditches are lined and reinforced with riorao or eravel. Some of the
ditches are concrete lined.

Detention/Sedimentation Ponds ^ Applicable ~ N/A

Siltation Area extent: Dcoth: 1"! N/A
Siltation not evident

Remarks: Remediation or removal actions have occurred historically to remove excess sediment from
waste ponds.

Erosion Area extent: Dcoth:

Erosion not evident
Remarks:

Outlet Works ^ Functioning ~ N/A
Remarks:

Dam ~ Functioning ^ N/A
Remarks:

H. Retaining Walls Applicable ~ N/A

Deformations Q Location shown on site map ^ Deformation not evident
Horizontal displacement: Vertical displacement:

Rotational displacement:

Remarks: Some retaining walls were observed alone the access roads to the waste oilcs of OU6 and
included cribbine and casins to prevent erosion onto access roads.

Degradation Q Location shown on site map ^ Degradation not evident
Remarks:

I. Perimeter Ditches/Off-Site Discharge ^ Applicable ~ N/A

Siltation ~ Location shown on site map ^ Siltation not evident
Area extent: Depth:

Remarks: An elaborate network of diversion ditches are constructed throughout OU2. 4. 5. 6. 7. 8. 9 and
10 to divert runoff to oonds and treatment facilities.

Vegetative Growth Q Location shown on site map ^ N/A
1 1 Vegetation does not impede flow

Area extent: Tvpe:
Remarks:

Erosion Q Location shown on site map ^ Erosion not evident

Area extent: Depth:

Remarks:

Discharge Structure £3 Functioning Q N/A

Remarks: The Mav 2015 time-critical removal action in the Greenback Pond area has included a eravitv-
fed nine to discharge overflow to the Robert Emmet area.

VIII. VERTICAL BARRIER WALLS ~ Applicable ^ N/A

F-8

-------
1.

Settlement Q Location shown on site map Q Settlement not evident

Area extent: Depth:

Remarks:

Performance Monitoring Tydc of monitorins:

1 1 Performance not monitored

Freauencv: 1"! Evidence of breachins

Head differential:

Remarks:

IX.

GROUNDWATER/SURF ACE WATER REMEDIES ^Applicable ~ N/A

Groundwater Extraction Wells, Pumps and Pipelines ~ Applicable ^ N/A

Pumps, Wellhead Plumbing and Electrical

~ Good condition Q All required wells properly operating Q Needs maintenance Q N/A
Remarks:

Extraction System Pipelines, Valves, Valve Boxes and Other Appurtenances

~ Good condition Q Needs maintenance
Remarks:

Spare Parts and Equipment

1 1 Readily available ~ Good condition ~ Requires upgrade ~ Needs to be provided
Remarks:

B. Surface Water Collection Structures, Pumps and Pipelines ^ Applicable ~ N/A

Collection Structures, Pumps and Electrical

1^1 Good condition Q Needs maintenance
Remarks:

Surface Water Collection System Pipelines, Valves, Valve Boxes and Other Appurtenances

Good condition ~ Needs maintenance
Remarks:

Spare Parts and Equipment

Readily available ^ Good condition Q Requires upgrade Q Needs to be provided
Remarks:

Treatment System ^ Applicable ~ N/A

Treatment Train (check components that apply)

Metals removal Q Oil/water separation Q Bioremediation
~ Air stripping O Carbon adsorbers
Kl Filters: O&M contractor replaces media filters as reauired.

Kl Additive (e.g.. chelation asent. flocculent): Addition of lime to increase dH and use of uolvmer to
allow metals to fall out.

F-9

-------

I-! Others:

1X1 Good condition Q Needs maintenance

1X1 Sampling ports properly marked and functional

1X1 Sampling/maintenance log displayed and up to date

1X1 Equipment properly identified

I"! Ouantitv of eroundwater treated annually:

IXI Ouantitv of surface water treated annually: 260 million (since 2006 and averaeed)

Remarks:

Electrical Enclosures and Panels (properly rated and functional)

1 1N/A ^ Good condition Q Needs maintenance

Remarks: Panels were dresent at OU1 and OU6 Gaw pump house. Both are in eood condition.

Tanks, Vaults, Storage Vessels

1 1 N/A ^ Good condition Q Proper secondary containment Q Needs maintenance
Remarks:

Discharge Structure and Appurtenances

1 1 N/A ^ Good condition Q Needs maintenance
Remarks:

Treatment Building(s)

1 1 N/A ^ Good condition (esp. roof and doorways) Q Needs repair
1 1 Chemicals and equipment properly stored

Remarks: In March 2018. the EPA allowed a temporary modification to the Work Plan to be permanent
for the effluent to be discharged from the Yak Tunnel WTP at a more alkaline dH. which is above the
previously permitted maximum level. The modification expanded the upper value of the 30-dav averaee
pH ranee to 11.0. thereby eliminating the need to add sulfuric acid post treatment to brine plant effluent
within its previous permitted upper value of the pH ranee to 9.0.

Monitoring Wells (pump and treatment remedy)

1 1 Properly secured/locked Q Functioning Q Routinely sampled Q Good condition
1 1 All required wells located Q Needs maintenance ^ N/A
Remarks:

D. Monitoring Data

Monitoring Data

1X1 Is routinely submitted on time Is of acceptable quality

Monitoring Data Suggests:

1 1 Groundwater plume is effectively contained Contaminant concentrations are declining

Monitored Natural Attenuation

Monitoring Wells (natural attenuation remedy)

1 1 Properly secured/locked Q Functioning Q Routinely sampled Q Good condition
1 1 All required wells located ~ Needs maintenance N/A
Remarks:

F-10

-------
X. OTHER REMEDIES

If there are remedies applied at the site and not covered above, attach an inspection sheet describing the physical
nature and condition of any facility associated with the remedy. An example would be soil vapor extraction.

XL OVERALL OBSERVATIONS

Implementation of the Remedy

Describe issues and observations relating to whether the remedy is effective and functioning as designed.
Begin with a brief statement of what the remedy is designed to accomplish (e.g., to contain contaminant
plume, minimize infiltration and gas emissions).

The remedy at OU 1 is designed to intercept and treat contaminated surface water nrior to reaching the
Lower California Gulch. The Yak Tunnel WTP has been in continuous operation since 1992 and all
effluent discharge meets criteria established in the 2008 Consent Decree. A number of lid grades to the
olant hardware, software, electrical conduit, treatment system and surge oond have been completed since
the previous FYR. The plant is in good working order and will continue to treat influent from the mine
drainage systems linked to Yak Tunnel.

The remedies at OUs 2 through 11 were designed to address metals source contamination orior to the
design and implementation of the sitewide groundwater and surface water remedy under OU12. Source
control efforts have largely included the excavation and consolidation of contaminated materials,
including mine tailings, slag and waste rock. These remedies also included the construction of an
extensive

network of surface water diversion structures to minimize leaching of metals from these oilcs and to
Drcvent ARD from further impacting surface water at the Site. Phase I remediation is completed at OU6 to
control sources. Phase 2 (waste rock nilc canning) and Phase 3 (resizing of collection channels and nonds)
is ongoing. An evaluation of whether more work is needed at other source areas will be made based on the
results of the OU 12 long-term groundwater and surface water monitoring. In addition, implementation of
institutional controls for OU 11 is currently underway and institutional controls are planned as the OU6
remedy nearing comnlction.

Adequacy of O&M

Describe issues and observations related to the implementation and scope of O&M procedures. In
particular, discuss their relationship to the current and long-term protectiveness of the remedy.
O&M activities largely include monitoring and maintenance of the implemented remedies. The Yak
Tunnel WTP is routinely monitored as Dart of dav-to-dav one rations and renairs and maintenance are
Dcrformcd as needed. Some nilcs of contaminated material have a gravel or vegetative can: these are
maintained bv the annronriate narties.

Early Indicators of Potential Remedy Problems

Describe issues and observations such as unexpected changes in the cost or scope of O&M or a high
frequency of unscheduled repairs that suggest that the protectiveness of the remedy may be compromised
in the future.

Opportunities for Optimization

Describe possible opportunities for optimization in monitoring tasks or the operation of the remedy.
The OU1 remedy was optimized in March 2018. modifying the dH in the effluent discharged from the
Yak Tunnel WTP to a more alkaline dH. thereby eliminating the need to add sulfuric acid oost treatment
to bring nlant effluent within its previous Dcrmittcd dH range. OU6 remediation is ongoing and includes
imnrovcmcnts to diversion ditches and conveyance systems to address increased volumes of water during
high water events (snow melts).

F-ll

-------
APPENDIX G - SITE INSPECTION PHOTOGRAPHS

QUI - Yak Tunnel Water Treatment Plant

OU1 Yak Water Treatment Plant	OU1 - Yak Water Treatment Plant Surge Pond

G-l

-------
QU2 - Malta Gulch Tailings Impoundment (automobile tires observed in photos)

OU3 - Slag Pile

G-2

-------
0U3- Former Harrison Street Slag Pile (location for new courthouse and jail)

Mineral Belt

Trail Sfl

S3 £»ki«J3ike
Wi»Ik» Hike

0U3 - Mineral Belt Trail with new homes built in the background

G-3

-------
0U4 - View from Helen Waste pile showing cribbing along road and drainageway

iCftM

OU4 - View from Helen Waste pile showing cribbing along road and drainage controls

G-4

-------
0U5 - Drainage feature near former smelter area

G-5

-------
0U6 - Greenback Pond and fencing around pond

OU6-

OU6 - Pyrenees Waste Rock Pile
and drainage feature

OU6 - Fencing needing repair at Marion Pond

Mahala Waste Rock Pile

OU6 - Highland Mary Waste Rock Pile

G-6

-------
G-7

-------
0U6 - Surface runoff diversion ditches and structures

G-8

-------
0U6 - Diversion structure under road

OU6 - Starr Ditch diversion structures

G-9

-------
0U6 - Repository for remediated soils from other OUs and associated pond

OU7 - Apache Tailings Impoundment

OU9 - Lead remediated residential home and community where lead remediation has occurred

G-10

-------
OU11- Arkansas River near Hayden Ranch

OU-12 - Monitoring well

OU12 - California Gulch sample location CG6

G-ll

-------
OU-12 - Arkansas River monitoring location Segment 2a

OU12 - Arkansas River monitoring location Segment 2b

G-12

-------
APPENDIX H - DETAILED ARARS REVIEW

CERCLA Section 121(d)(1) requires that Superfund remedial actions attain "a degree of cleanup of hazardous
substance, pollutants, and contaminants complete into the environment and of control of further release at a
minimum which assures protection of human health and the environment." The remedial action must achieve a
level of cleanup that at least attains those requirements that are legally applicable or relevant and appropriate.
Applicable requirements are those cleanup standards, standards of control, and other substantive requirements,
criteria or limitations promulgated under federal environmental laws or state environmental or facility citing laws
that specifically address a hazardous substance, remedial action, location or other circumstance found at a
CERCLA site. Relevant and appropriate requirements are those standards that while not "legally applicable"
address problems or situations sufficiently similar to those encountered at the CERCLA site and that their use is
well suited to the particular site. Only the state standards that are more stringent than federal requirements may be
applicable or relevant and appropriate. To-be-considered (TBC) criteria are non-promulgated advisories and
guidance that are not legally binding, but may be considered in determining the necessary remedial action. For
example, TBC criteria may be particularly useful in determining health-based levels where no ARARs exist or in
developing the appropriate method for conducting a remedial action.

Chemical-specific ARARs are health- or risk-based numerical values or methodologies that, when applied to
site-specific conditions, result in the establishment of numerical values. These values establish an acceptable
amount or concentration of a chemical that may remain in, or be discharged to, the ambient environment.
Examples of chemical-specific ARARs include MCLs under the federal Safe Drinking Water Act (SDWA) and
ambient water quality criteria (AWQCs) enumerated under the federal Clean Water Act.

Action-specific ARARs are technology- or activity-based requirements or limits on actions taken with respect to a
particular hazardous substance. These requirements are triggered by a particular remedial activity, such as
discharge of contaminated groundwater or in-situ remediation.

Location-specific ARARs are restrictions on hazardous substances or the conduct of the response activities solely
based on their location in a special geographic area. Examples include restrictions on activities in wetlands,
sensitive habitats and historic places.

Remedial actions are required to comply with the ARARs identified in the ROD. In performing the FYR, any
newly promulgated standards including revised chemical-specific requirements (such as MCLs, ambient water
quality criteria), revised action and location-specific requirements, and state standards if they were considered
ARARs in the ROD, are reviewed to establish whether the new requirement indicates that the remedy is no longer
protective.

Groundwater

Final performance standards for OU1 through OU11 did not include chemical-specific ARARs for surface water
and groundwater. It was agreed that the decision on remediation of OU12 (Sitewide Water Quality) would be
made between the EPA and the PRPs, and memorialized in the Consent Decree only after remedies for source
remediation was selected and implemented at each OU.

The OU12 ROD identified federal drinking water standards for arsenic, cadmium and lead as groundwater
ARARs. However, according to OU12 ROD, shallow groundwater is not expected to meet ARARs within a
reasonable timeframe. Thus, the EPA issued a TI waiver for a small portion of the Site for cadmium and lead in
the shallow alluvium of Stray Horse, California and Oregon gulches, as well as a portion of the AV floodplain
near the confluence of California Gulch (Figure H-l). The OU12 ROD did not waive the MCL for arsenic since
there were no exceedances of the arsenic MCL (Table H-l).

H-l

-------
Table H-l: Previous and Current ARARs for OU12 Groundwater COCs

()l 12 2012 KOI)

( iinvnl

<()<

Alt Alt

MCI.

AK AK (

(mii/l. );lh

(HSi/l.)-'

Arsenic

0.01

None

Cadmium

0.005 (waived)

0.005

None

Lead

0.015 (waived)

0.015

None

Notes:

Obtained from 2009 OU12 ROD, page DS-49.

Based on the SDWA MCLs. Current MCLs can be found at

httos://www.era.eov/eround-water-and-drinkine-water/table-reeulated-

drinkine-water-contaminants (last accessed 4/12/2022).

mg/L = milligrams per liter

Hg/L = micrograms per liter

Surface Water

The 1989 OU1 AROD waived attainment of the federal AWQC for the discharge from the Yak Tunnel WTP.
Further, in the 1991 ESD, the EPA waived water quality-based effluent limitations and standards for the Upper
Arkansas River since, at that time, it was not yet possible to perform a waste load allocation to determine the
extent to which the Yak Tunnel discharge and each of the other discharges must be treated to in order for the
Arkansas River to meet instream water quality requirements. However, technology-based treatment requirements
that represent the minimum level of control had not been waived. According to the 1991 ESD, the WTP effluent
must meet best available technology requirements based on acute toxicity testing after two years of operation. The
2008 Consent Decree established effluent discharge limitations that apply to the discharge at Outfall 001 (Consent
Decree, Appendix A, Table l)(Table H-2). These values continue to be used to monitor the concentrations of
cadmium, copper, mercury, lead and zinc at Outfall 001.

The 2009 OU12 ROD identified the Colorado Water Quality Control Act (5-CCR-1002.31) and applicable water
quality standards established for the on-site segments of the Arkansas River and California Gulch under the
Classification and Numeric Standards for the Arkansas River Basin (5 CCR 1002-32) as ARARs for OU12
surface water. The ROD identified seasonal temporary modifications to the 5 CCR 1002-32 table value standards
set for cadmium and zinc for the months of April and May in the 2b and 2c segments of the Arkansas River. For
the remainder of the year, hardness-dependent concentration values are identified as the water quality standards
and replace the table value standards. CDPHE updated the water quality criteria in December of 2021. The
hardness-dependent chronic concentrations for cadmium and zinc table value standards have not changed since
the ROD was issued (Table H-3). In addition, the hardness dependent acute concentration for zinc has not
changed but the current acute hardness dependent criteria for cadmium have become less stringent. The seasonal
temporary modifications for segment 2b and 2c expired on December 31, 2013, and renewed in 2021 for both
segment 2b and 2c; the seasonal values for segment 2b have not changed since the 2009 OU12 ROD, while more
stringent seasonal values were established for 2c. These changes do not affect monitoring performance of the
remedy, as the monitoring plan has adopted the most current surface water ARARs.

H-2

-------
Table H-2: Yak Tunnel WTP Effluent Limits

Parameter"

Effluent Limitations

30-Day
Average1'

Daily Max"

Frequency1

Sample

Type"

Flow, MGD

Report

Daily

Continuous

pH, s.u.J

6.0-9.0

Report

Daily

Continuous

Oil and Grease, mg/Le

Report

10.0

Daily/Weekly

Visual/Grab

Total Calcium, mg/L

Report

Monthly

Composite

Total Magnesium, mg/L

Report

Monthly

Composite

Hardness, mg eq. CaC'CVL

Report

Monthly

Composite

TSS, mg/L

Monthly

Composite

TSS, lbs/day (kg/day)

240(109)

360(163)

Monthly

Composite

Ag-TR, pg/LH

Report

Monthly

Composite

Ag- TR, lbs/day (kg/day

Report

Monthly

Composite

Al- AS, pg/L

Report

Monthly

Composite

Al- AS, lbs/day (kg/day)

Report

Monthly

Composite

As- TR. ue/L

Report

Monthly

Composite

As- TR, lbs/day (kg/day)

Report

Monthly

Composite

Cd- TR. ug/L

100

Monthly

Composite

Cd- TR, lbs/day (kg/day)

Report

Monthly

Composite

Cu- TR, pg'L

150

300

Monthly

Composite

Cu- TR, lbs/day (kg/day)

Report

Monthly

Composite

Fe- TR. ug/L

Report

Monthly

Composite

Fe- TR, lbs/day (kg/day)

Report

Monthly

Composite

He- T. ug/LH

Monthly

Composite

Hg- T, lbs/day (kg/day)

Report

Monthly

Composite

Pb- TR. ue/L

300

500

Monthly

Composite

Pb- TR. lbs/day (kg/day)

Report

Monthly

Composite

Mn- TR, (ig/L

Report

Monthly

Composite

Mn- TR, Ibs/dav (kg/day)

Report

Monthlv

Composite

Se- TR, n^/day

Report

Monthly

Composite

Se- TR, lbs''day (kg/day)

Report

Monthly

Composite

Zn- TR, ug/L

750

1500

Monthly

Composite

Zn- TR, lbs/day (kg/day)

Report

Monthly

Composite

Whole Effluent Toxicity, Acute

Semi-Annual

Composite

There shall be no discharge of floating solids or visible foam in other than trace amounts.

T - Total, TR - Total Recoverable. AS = Acid Soluble

a -In addition to monitoring the final discharge at Outfall 001. influent samples shall be taken at the locations described in Section 5.0 and analyzed for all listed
parameters

b -See Section 3.0 for definition of terms. For reporting of effluent loading calculations, measurements less than the practical quantitation level shall be considered as
zero. For reporting of effluent concentrations, the actual concentration will be reported. If the effluent concentration is less than the PQL. a " H will be used for
the concentration. For influent concentrations* individual water sources will be reported separately. For reporting influent loading calculations, measurements less
ihan the practical quantitation level shall be considered as zero. For reporting of influent concentrations, the actual concentration will be reported. If the influent
concentration is less than the PQL. a ** will be used for the concentration,
c -Operator may request and EPA may allow a change in the monitoring frequency,
d -Daily minimum - daily maximum limitation

e -A grab sample shall also be taken from Outfall 001 if a visual sheen is observed.

f -Hardness shall be calculated using the total calcium and magnesium sample analysis from the monthly samples.

g -Serni-annual acute toxicity in the discharge from Outfall 001 is to be conducted. This testing is alternated between C'enodaphnia and fathead minnow at each semi-
annual test.

h - For the purpose of this plan, the practical quantitation level for total recoverable silver and total mercury is considered to be 1.0 jig; L. Analytical values less than
1.0 gg/L shall be reported as "and will be considered to be m compliance with the effluent limitations for total mercury and total recoverable silver. For loading
calculations of mercury and silver analytical results, measurements less than the practical quantitation level shall be considered to be zero.

Source: 2008 Consent Decree, Appendix A, Table 1.

H-3

-------
Table H-3: Comparison of 2009 OU12 Surface Water ARARs to Current Standards

(¦<>(¦

Wilier
Qu;ilil\
Siiindiird

2IMWOI 12 KOI) ARARs lor
Arkiinsiis Ki\cr Segments 21)
iind 2c (iiii/l -

( iirrcnlt DI'lll. Siiindiirds

(,u»/l.)h
2h iind 2c

( liiinuc'

Cadmium

June-March

Acute: 1.136672-[ln(hardness) x
0 041838] xe(a915i[in(harti|iess)]-3-6236)

Acute: 1.136672-
(ln(hardness) x 0.041838) x

g(0.9789[ln(hardness)]-3.866)

Less stringent

Chronic: 1.101672-[ln(hardness)
x 0 041838] x e(°-7998[ln(hardness)]-

3.1725)

Chronic: 1.101672-
[ln(hardness) x 0.041838] x

g(0.7998[ln(hardness)]-3.1725)

No change

Seasonal
Modification
(April-May)

1.34

NA

NA

Zinc

June-March

Acute: 0.978 x

e(0.8537[ln(hardness)]+2.2178)

Acute: 0.978 x

e(0.8537[ln(hardness)]+2.2178)

No change

Chronic: 0.986 x

g(0.8537 [ln(hardness)]+2.0489)

Chronic: 0.986 x

g(0.8537 [ln(hardness)]+2.0469)

No change

Seasonal
Modification
(April-May)

649 (ng/L)

NA

NA

Notes:

Criteria listed in 2009 OU12 ROD pages DS-48 and DS-49, Segments 2b and 2c are located directly
downstream from the confluence of California Gulch.

Based on the water quality standard established for the on-site segments of the Arkansas River and California
Gulch under the Classification and Numeric Standards for the Arkansas River Basin (5 CCR 1002-32)
http://www.sos.state.co.us/CCR/DisplavRule.do?action=ruleinfo&ruleId=2360&deptID=16&agencvID=132&d
eptName=Department of Public Health and Environment&agencvName=Water Quality Control Commission
(1002 Series)&seriesNum=5 CCR 1002-32 (last accessed 4/12/2022).

Based on a comparison assuming a hardness of 100 mg/L calcium carbonate.

NA - not applicable, the seasonal modifications are no longer applied to these segments starting in 2014.





Anile

( hionic



KOI)

( ii rrenl

KOI)

( iirrcnl

<¦<><¦

2h iind 2c

21) iind 2c

21) iind 2c

21) iind
2c

Cadmium

1.7

1.79

1.51

1.51

Zinc

458

458

390

390

H-4

-------
Figure H-l: TI Waiver Area at the Site

wjaleadville "

Ml

Boundary For
Technical Impracticability Waiver

^	Mine Tunnel	C3 ^a'
-------
APPENDIX I -DATA TRENDS

Table 1-1: OU1 Bedrock Groundwater Quality at Monitoring Well BBW-5, 2007 to 2020



1

I

*

-

t

1

1

.

1
*

.

«•
*

.

1

»

1

1
...

s

B.

|

5

S





AIMimi- asraCXB



m

16*

i;v



n

if 3



>

\V



iSi .





A '		

-¦m





-4)03

-¦&M



-AOl

H

.¦ ¦.!.' t



-







i



•*}>**¦

• .5 fHPt

¦a.KJOf



-uxteit

¦-i>,0?KK>S

,>!?

i:MWS

•••¦.wrop



'wmw





CiiviwR

HIS

i.v



l«

IM

\ <¦



h-i

as

i -

...







umnm

I.,

i...\

fv,

J 1

n.»

t >

*5

i.S

IV? 13

>>.« B

-

l ! «,*,¦







Uv

w»

sw



*4*

*«>

f f

s 1 ¦'

¦*iv:

"Jii:



•-n;^





c4ppw



<0 .'Riijf



<•« t&:&$

•ii tKKR

-.'0e»CK



i IV







Cll

^ 4.S0

im

3M

m

4,life

J.S4

IS

.186

155

- p Oft





i li'SL!



omi



1 i>

i.»

A

« f

j i.»5





S-itw

i I."



i :

s :>

i:



n.?

i.

11.6

IIJ

| <"3,!





Sodfcttl

2,

-.4

2.2

12

I 2.)



2.2

2;





1 i,.i«





. ¦ r :. , > v .

2«



,.;

I V

I?7



i?j

J-.V,

.is

3.M

| 117





IDS

551



m

5W

sift





5«

m

mi









Zmc

IMJ4

0.152

f.nt

0.2H

:: Jt:

".274

OJ45

taut

mm



_

11+15







At'MBiik ItsjlcKKIfJl illtlKUta

. . : . i ... ,1.'		

1-1

-------
Table 1-2: Yak Tunnel Blockage Water Quality, 2007 to 2020

Source: Yak Annual Monitoring Report 2020. Prepared by Resurrection Mining Company. March 2021.

1-2

-------
Table 1-3: Summary of Yak Tunnel Blockage Water Pumping and Water Levels, 2020



Monthly

{BiifiengillMS)

Cream*™ter ^Esffamted Water

I Mmuied (.routtdwater
Level Change from 3/21/06

m\am

NA

(1

10.684

289

KA

i a 1/2020

24.8

3,679.2

10,662

26?

-22

2/29/2020

26,2

' !<-, J

10.65?

262

-27

3/31/2020

27.2

V* ' 1.

10.653

r 258

-31

4/302020

215

3,760.1

10,647

252

* -37

5/31/2020

21.7

3,781.S

10.650

255

-34

6/30/2020

22,3

3,804.1

10,660

265

r~ -24

7/31/2020



3,826.)

10.664

269

-20

8/31/2020

26.8

i Hi-' M

a.:..ow:./

265

-24

y/30a020

23.7

3.876.6

10,659

264



V V {1

33.4

3,9 0.7

Hifwi

236

-33

11/30/2020

,'i.O

3.941.7

i 0,645

250

-39

12/31/3020

3! ,0

3.072,7

10.639

244

-45

(1} Voitiiisc smmpeti since imtiwkmt^mnpin^of Yak I'u-md blockageon Match 21. 2006

Table 1-4: OUIO Groundwater Quality from Monitoring Well OG1TMW3

Source: OU-4 ;ind OU-10. 2020 Inspection Report. California Gulcli Superfund Site. Prepared by Engineering Analytics, Inc.
February 2021.

Table 1-5: CSU Macroinvertebrate Sampling Summary in the Arkansas River near Leadville

CSU Sample

Oil 12 Aquatic Life
Monitoring Program
Location

Year

Spring*

Fair

a Spring to Fall

Loeatten

# Individuate

# Tua

% Heptageniidae

# individuals

#Taxa

* Heptageniidae

# individuals

# Taxa

H Heptagenndae





2014

2BG.4

30.8

Am*

NM

m

UM











2015

352.6

30,4

2.1%

316.2

3S.f



S,J

-0,4







im s

336.2

2?, 6

4.8%

307.6

30.B

11.9%

-a.





AR1

AR-1

201?

315,2

29.6

6.4%

34SU

32.4

10.?%











2018

....

74 v

.1 CX

117 *

33.2

7 TO

k.C



....





2021

MM

U*

IW!

,,4>

28.2













202! »5 Average









-2.7









2014



T



V

'¦

M'











2015

iw a

Si A

JUVS,

347.2

¦u H

E.H'JB

,n®



n™





291 e

179.8

21.0

7,2%

325.6

27 A

3 m

I." I1

> «



AR3

AR-3A

2017

137.2

25 9

'! 7»?r

3.64.2

34 17

7 1%

-r.u



r





20«

339.6

31.6



1' i





,n









2021

W,'

M/

MM

i.-r















2021 vs Average









-:4

•1.3%







2014

.



I

E.

r,f<«

NV











2015

335.0





3 .in fi



0.0%







AR5

AR-5

2016







,_1 r





vt





2017



31.2

- "

- i

:c •'

I I



4 4







2018



I M

f.K'

469.2

30,2!

1.0%











2018 vs Average









•1.2

-0.4%







2014

i;.

:?

0

M7

W

l.v











2015

122,4

10.4

am

88.8

8.6









CG

CG-6

2S16

30.0

5.4

0.0%

27IS-S

9.2



.l< !





2017







lrin.









1 ? .





2Q1B

UM

Ul

M"





0.(3%











2018 vs Average











n



V?

a

BokkKi and siwtejfffCKt roffiit

reorestwK roaxirottm value for 6|fecifr

trxxtfixtfiq mm.















4!

For "2021 vs Av«fag»". a RED vateiiKtainstlias

value is J

S* than llx? 5 ye*



'X vote mtfeaies stwt tt*» 2Q21 va









I Km-.i! ante i 4 .MsiraKvWiiljsiB S®sp8n^ C5;3. 20? I slut

1-3

-------
FRYER
HILL

, YAK TUNNEL
BLOCKAGE,

IRENE SHAFT,

l \ M bbW-1

1330 LATERAL

YAK WATER
V TREATMENT
PLAN

BULKHEAD

tV//

YAK TUNNEL
PORTAL

BLACK CLOUD

HELENA
"SHAFT

BLACK CLOUD
TAILINGS PILE

LEGEND

a SHAFTS

	MINE DRAINAGE

TUNNEL

*	PIEZOMETER

•	MONITORING
WELL

	FAULT

worth/

SCAIC ti FEET

5 i

E g



1-4

-------
Figure 1-2: OU12 Surface Water Monitoring Locations



meadvilOe]

[MOOtfTAJtlj

IccAicorl

lOJHTyj

TETRATECH

OU12 SURFACE WATER
MONITORING LOCATIONS

1-5

-------
Figure 1-3: OU12 Groundwater Monitoring Locations

1) AERIAL PHOTOGRAPHY FROM SUMMER OF 2015,
PROVIDED BY USDAIFSA NAIP PROGRAM

SEE STRAY HORSE OULCH

IgEWDVllIijEi

SEE APACHE TAILING
1 IMPOUNDMENT BLOW



llMPOjjJIDMENTj

| STRAY HORSE GULCH AREA]

TETRATECH

CALIFORNIA GULCH SUPERFUND SITE

OU12 GROUNDWATER
MONITORING LOCATIONS

1-6

-------
Figure 1-4: OU12 Aquatic Life Monitoring Locations

3 BENTHIC MACRONVERTEBRATE S FISH POPULATION MONITORING LOCATION

Stream Segments

11 AERIAL PHOTOGRAPHY FROM SUMMER OF 2015.
PROVIDED BY USOA/FSANAIP PROGRAM



TETRATECH

OU12 AQUATIC LIFE
MONITORING LOCATIONS

1-7

-------
Figure 1-5: Zinc Loading to the Arkansas River from Surface Water Sources at CG-6, 2019

¦ Upper Arkansas River Basin (AR-1)

California Gulch (CG-6)

Source: 2019 OU12 Annual Report.

Figure 1-6: Cadmium Loading to the Arkansas River from Surface Water Sources at CG-6, 2019

Source: 2019 01X12 Annual Report.

1-8

-------
Figure 1-7: Dissolved Zinc Concentrations and Load at AR-1 and AR-3A

O

O

Sep-19	Ocl-19

-AR-1 Dissoh/ed Zinc Load

0.0

Mar-19	Apr-19	May-19	Jun-19	Jul-19	Aug-19

AR-3A Dissolved Znc Concentrafien AR-1 Dissolved Zinc Concentration —AR-3A Dissolved Zinc Load

600

Figure 1-8: Dissolved Cadmium Concentrations and Load at AR-1 and AR-3A

0.0015

0
•19

Apr-19	May-19	Jun-19	Jul-19

Aug-19

Sep-19	Oct

0.0005

o

¦O

AR-3A Dissolved Cadmium Concentration
-AR-3A Dissolved Cadmium Load

AR-1 Dissolved Cadmium Concentration
-AR-1 Dissolved Cadmium Load

1-9

-------
Figure 1-9: Zinc Loading to the Arkansas River from Surface Water Sources at CG-6, 2021

100%

Sep-21

¦ Upper Arkansas River Basin (AR-1) California Gulch (C6-6)

Source: 2021 OU12 Annual Report.

Figure 1-10: Cadmium Loading to the Arkansas River from Surface Water Sources at CG-6, 2021

Sep-21

¦ Upper Arkansas River Basin (AR-1) California Gulch (CG-6)

Source: 2021 OU12 Annual Report.

1-10

-------
Figure 1-11: Flow and Dissolved Zinc Concentrations at AR-3A

0.5

_ 0.4 -

_J

6)

E

2 0.3
£

—i—i——¦—1—1—1—i—¦—1—1—i—i-

-- 800

1,000

600

i/>

5
o

nj
Q

400 g,
re

k.

ai
>
<

DC

200 <

0.0
3/1/2021

4/1/2021

5/2/2021

6/2/2021

7/3/2021

8/3/2021

9/3/2021

Dissolved Zinc (mg/L) - Meets Chronic Standard
• 2021 AR 1 Avg. Daily Flow (cfs)

• Dissolved Zinc (mg/L) - Exceeds Chronic Standard
	Historic AR 1 Avg. Daily Flow (cfs)

O:\8596\117-8596006\Docs\Reports\Annual Report\Figures\Ready for Drafting



COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT

Project No.: 117-8596006

¦11. TETRATECH

CALIFORNIA GULCH SUPERFUND SITE

Date: 07/31/2022

L«Cj

2021 ANNUAL MONITORING REPORT

Designed By: JAB

www.tetratech.com

FLOW & DISSOLVED ZINC CONCENTRATIONS

Figure

3-7

V

351 Coffman Street, Suite 200
Longmont, Colorado 80501
Tel (303) 772-5282

AT AR-3A

Bar Measures 1 inch

1-11

-------
Figure 1-12: Flow and Dissolved Cadmium Concentrations at AR-3A

E

o

d>
o
e
O
O

E

2

E

"D

flj

O

¦S

>

o

CO

•SI

0.0025

1,000

0 0020

0.0015

0.0010

0.0005

0.0000

3/1/2021

4/1/2021	5/2/2021	6/2/2021

Dissolved Cadmium (mg/Li - Meets Chronic Standard
• 2021 AR-1 Avg. Daily Flow(cfs)

7/3/2021	8/3/2021	9/3/2021

Dissolved Cadmium (mg/L) - Exceeds Chronic Standard
— Historic AR-1 Avg. Daily Flow(cfs)

Q:\8596\117-8596006\Docs\Reports\Annual Report\Figures\Ready for Drafting

TETRATECH

	www.tetratech.com

351 Coffman Street, Suite 200
Longmont, Colorado 80501
Tel (303) 772-5282

COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT

CALIFORNIA GULCH SUPERFUND SITE
2021 ANNUAL MONITORING REPORT

FLOW & DISSOVED CADMIUM CONCENTRATIONS
AT AR-3A

Project No.:

117-8596006

Date:

Designed By:

Figure

3-8

Bar Measures 1 inch

1-12

-------
APPENDIX J - INTERVIEW FORMS

CALIFORNIA (;i IX IISl I'Lkl I M) SI I L
I'l YL-YLAR RKYIKW INTKRYIENY FORM

Site Name: California Gulch

EPA ID: COD980717938

Interviewer name:

Interviewer affiliation:

Subject name: Devon Horntvedt

Subject affiliation: Newmont Director, Site
Management	

Subject contact information: devon.horntvedt@newmont.com

Interview date: 7/7/22

Interview time: 12:00

Interview location: Email

Interview format (circle one): In Person

Phone

Mail

Email X Other:

Interview category: Potentially Responsible Party (PRP)

1.	What is your overall impression of the remedial activities at the Site?

The Site is in excellent shape, with significant upgrades and evaluations of remedial facilities taking place
every year. Continuous improvement programs, additional internal company oversight, and excellent on-site
management have the Site in as good a shape as it has ever been.

2.	What have been the effects of the Site on the surrounding community, if any?

Largely positive, especially relative to prior to any site activities taking place in the 1980s. The Arkansas river
runs much cleaner, and now recreational and other opportunities for the community continue to be built
around and expounded upon.

3.	What is your assessment of the current performance of the remedy in place at the Site?

The remedy is performing extremely well. The Arkansas River, the primary receiving body to any
environmental site impacts, is as healthy as it has been in modern history.

4.	Are you aware of any complaints or inquiries regarding environmental issues or the remedial action from
residents since implementation of the cleanup?

No.

5.	Do you feel well-informed regarding the Site's activities and remedial progress? If not, how might the EPA
convey site-related information in the future?

Yes.

6.	Do you have any comments, suggestions or recommendations regarding the management or operation of the
Site's remedy?

Not at this time.

7.	Do you consent to have your name included along with your responses to this questionnaire in the FYR
Report?

Yes.

J-l

-------
CALIFORNIA (;i IX IIS1 I'LRI I NDSITK
Fl\ L-YLAR REYIKNY INTKRYIKNY FORM

Site Name: California Gulch

EPA ID: COD980717938

Interviewer name:

Interviewer affiliation:

Subject name: Devon Horntvedt

Subject affiliation: Newmont Director, Site
Management	

Subject contact information: devon.horntvedt@newmont.com

Interview date: 7/7/22

Interview time: 12:30

Interview location: Email

Interview format (circle one): In Person

Phone

Mail

Email X Other:

Interview category: O&M Contractor/Staff

1.	What is your overall impression of the project, including cleanup, maintenance and reuse activities (as
appropriate)?

The project is going very well. O&M activities have largely reached a steady state except for capital
investment in the treatment facilities which are undergoing refurbishment now that they're 30 years into their
life. Reuse activities continue to be developed, largely in recreation, in the form of new trail easements and
recreational access. Secondarily, recreation on the Arkansas River continues to set records as the river system
is as healthy as it has been in modern history.

2.	What is your assessment of the current performance of the remedy in place at the Site?

The current remedy is performing very well.

3.	What are the findings from the monitoring data? What are the key trends in contaminant levels that are being
documented over time at the Site?

Contaminant levels in the water drainage have largely remained the same or are trending generally down, but
vary due to seasonal precipitation. Regardless of those variations, the treatment systems can handle those
variations and produce high quality effluent that meets the discharge standards.

4.	Is there a continuous on-site O&M presence? If so, please describe staff responsibilities and activities.
Alternatively, please describe staff responsibilities and the frequency of site inspections and activities if there
is not a continuous on-site O&M presence.

Yes. There are two on-site WTPs, although only the Yak WTP runs regularly and handles all site water
remediation. Two-to-three staff are on site during work hours and typically work 40 to 50 hours per week, and
staff are on call 24/7 throughout the week. Responsibilities include everything from day-to-day operations of
the WTP to daily sitewide inspections of all pumping and water collection facilities. General sitewide
inspections of the site, stormwater controls, institutional controls and all remedial facilities are performed
regularly.

5.	Have there been any significant changes in site O&M requirements, maintenance schedules or sampling
routines since start-up or in the last five years? If so, do they affect the protectiveness or effectiveness of the
remedy? Please describe changes and impacts.

There have been no major changes to site O&M requirements.

6.	Have there been unexpected O&M difficulties or costs at the Site since start-up or in the last five years? If so,
please provide details.

J-2

-------
Nothing that hasn't been anticipated. Some of the remedial facilities have reached their end of engineered life
and these facilities are constantly being evaluated, upgraded and/or replaced.

7.	Have there been opportunities to optimize O&M activities or sampling efforts? Please describe changes and
any resulting or desired cost savings or improved efficiencies.

There may be some opportunities to reduce sitewide groundwater monitoring requirements, given so few
changes have been noted since the initial and ongoing evaluation and monitoring.

8.	Do you have any comments, suggestions or recommendations regarding O&M activities and schedules at the
Site?

Not at this time.

9.	Do you consent to have your name included along with your responses to this questionnaire in the FYR
Report?

Yes.

J-3

-------
APPENDIX K- INSTITUTIONAL CONTROLS

Figure K-l: 2009 County Institutional Control for Operable Units 3 and 8

A SESOtUTtON AMENQtNC THE IARE COUNTY UW DEVELOPMENT
COW AND ADOmWG KBQUlATtONS CONCEKWIMQ tSSnTUTlONAL CWmOtS

mi o«*AfitE usns wmw the califokmm quick sitbk jnd »rrc

WWKBRAS, dM BomA ci C+mmy CoaiiMegM at ib» RnwiJr of <4*e. Mm* of
Cohs»*> CBoMtf"). a '»u»* Ktawiitwinp; the alban rf ink* Camay. Cutario, purumf
® jttie iHajtosi, «ji;I

WliRUiAS, flu §ot®rt l*a UM > Imi Use md Dwetopmett AppUoSMM, file
wimlw AMI, jpjjwniig Art 4k Like Camy LmS DniltpiM Cote (LDCj be inHndtd to
suet th»	«f flw n«™ gitrknmmUl	*#e«T (P^AJ Rsowtl* of

nwraeo nt A«m» MenonMl* 0* icquin tatiSMMBal coaiorii fx dm CtBtww CwlrJi
bufrtrftimt SiS® ijfe^pscd to piTYim* eosCfcm&Kl.&d wilt &KS Wrtfls; bfcmllct! Mpfwpr.vMy, *r:4
«> aMLB Ob EPA ia Jiirtmt tfac CiMxnli Gi4eh Supwftisd SMti ten "if >UEMati fctamw
Lwt^Nn.)

WlBiffiAS, bconM Sn maiQwi to tim LOG wn Utitud by ciMe Retad, #8
*ppI«E*aaei fee w»» mjiwfed ta he ptii; *ad

WHEREAS, tim Lite Cmo^ land Dtwfcptfaao* Cotk d«w« nra sutierf; «**»
pmvMaat MnWidbMg iMHtntaoil «wt»l* (n ft* Onlitwwa CWqh JWfwftiod Site, «4

WH.O-!J-:a5., sis Kmdaml'ta llm htkm C»\«t l.iMl SevtispBN Coik ii nceMHiy W

mbl itmdsdB of icwiw md fcfimtwpr potuktn® te ioMMtiaRl eostrels far 4w C«kfant»
Gulcb	Sin; sad

WiKREAS, Use Lata Cwuty Hummi® OwojiBuett mi be Beari ®f Coiaify
r»«Bnt*»eo«T» Mrf t joint puMic hwiim ob &i» nwKcr ox fie j&Ji. irr of , 26W*.

ar,:i

the iikmrii d Courir*	hss	die. RmiatffimdiyM

oflte LAtCwmty yMlKieDtepialMrtwdito W*BP«i*€«iBB3ii»ta; mi

WHEREAS, (h* B®»4 trfCtwaay Corajntaraom Siai» i»t Ss»	«a«jihwa»i» «d

tike Cmirts Lml rte*rtn«aaift Cade are ee»ii*HS wiii the pwl*, slsoiasiw, polsow aad
odw p»

nnmMwn*

p»«SBwa w TMt wmm-m cowt'Comwsskwem
CWffllW«'Lm«»STATt«COI»U»

¦mjonwdiim

K-l

-------
1NHH1IIII

•i'J" «, i»KS5- SR5K—,

a J. .lEiKtfniiittsmS Cwtraii* far tta CtiHM* IMdi iiytffiM Sin

1.11, OMral Prevhiaaa

hi Pwjmt. PwwiHt lo to Coopttbragivc fin*in*3wtatel JUapgue.

CcraptMaifoa aad Liability Act (CERCJ.A), 41 tJJS.C. S«#l at seq. ud dw
NrtK*»lCootu*t«>ey Plaa+0 C.F.*. Purt 100, toe U.S. (aovtronmeat*] Protection

A®»y {IP A) fast Kls«oJ jon»iie* fer tta istaiu aftwabte vuris, of ibe
CaMfcrak (Melt Supartod Site (Site) wfeam Wb drtosBUsol ti*. iwttaeowsl
control* am nmiMmmf m ¦ lupptaiMBt to mgimwriiig cgoaral*, In swap? wa'.-ir
te# iapUKC, to maipJy wift appfoafafc St* Jaws, and to jwim kuamalwalfi!
md the cawlffiaiaeaL H* (wrptjte of ttefo wpinffen* "a to rwWiili KBtituiiowl
M«mb v> ant A® nsjoireMeMi of &e vtnoM FJPA Kaconl* of Decision or
Asrtjoo	tfcw* mquine faftitatiwal conlmli, to imp lament re^*nmw«

designed to peeved caataauiatn) xx!» from bekg haadled tCMrpropmarly. acd w
—*M EPA ta dtMttg M Site torn It* Nabonal frtcrWea Un (WPt).

8)	Tta» HfuiMicw m mktpwti paXMRt to die potvm ru-J iwOwnty

w»f«j«sJ by the law wf Uw Stm efCntawto,

C)	TTw board cf County CaaorauHtteo*!*, Couatf »f Lake. Sc»tt of

Colontds lbd» (btt.

t> time Mfuhtwo* mm neceswy to eewjjly with U.S. EwfeanmcmKl Freftsctsofc
A.gzmy rmuiiTEmaDls foe urtlbdiaeal consols lor foe vbims ope/abto unit*
of tfeo Ottfcmsii ttotcfc Sttfertaul Site.

2} Eaaetetwnl of tkaae nguUtoam k required by EPA » order to viae* dektion
of Hw wri«a opambte uuu from tie National ftiowwi ij«t (KPL).

3) The iwptaocatUUoc offbcw aatitwtiaatfl caaaroU which r*awlt«e eaeawtar.
«d ta&ttag	within eerettn loattion* of tie California Gulch

SaptrAari Site amy nwnieiire 4k dinwfcunct, wah, inhalnkn and

attention ofoantaatiaaied »fls, ihu p<*c»ttoly tetsowng usy mk p««d by
certdlp pjrtttM ef-S* Srt» to Ibe pubtk bMlth «nd afay,

PJ DiflmUm*.

I) faJsJorais, Gulp's	Sins, Ttuw aiau wifeJn Lite CMly cutuutvng

of «§>|*®3tBn»tel| 1S iquiR miiss «w AsslpBied m Ae California Gultii
St9*rfwl Site hy tin 0 S, Environnuntai ?ro«acti<3e Agency (EPA)
pufsuiHU, to Ac Co,i-i£Tc!i.tei!.ive Envkm^MaJ Rnpaat, Coei$ieoMtion tad
Ls»tiu:.iy Art, 42 U 6 C Sct«n . Intfitulioaki oonnoU nt non-engiBcattJ

isrtntw^ratj, t«di 
-------
IHIRVRRIN

* V VSODIr * T W
CHS SJ0f» DKWO

»«pf

1 *k« CVwtfy Rusctrdff

the aaefW of * tcawdy by UmWug Uod or fwww use andfar by p>o riding
wfatratwallmt Wpiwdi^'ortriite hw* betuvior it»lite.

4)	Nsdtnul WofMies Lift The National Wwrfc Li* (MP LI U ft* lift of
hwartnwi wag* «im atiglbla fist toarttuBi BWttdkl aetioo Smmstxi wader
tefeienl S^crteid ptognm. HPA w*y Aitct* kfical N?L at® if it
dtferaiiaH that no fiutftn lepniK u nquiwi i» potec* human teaJtin or the
«arifwawmt Ptnital deletions may aba be caaduetad at Sfljwftod »«s,

5)	Noe-Engt»«r»d Remedy. A ow-ojftoeBfwi remedy n tr, EFA-approved

mnedy oeaprittid of ¦ jce®r»ph»e»l tm of an cpenW* unit fins do« not
induda a «o|piiBftirt ranody. Nm-tmgjmmml wmaUm em be mmMraewd
upon. They n»j	poper «wb®§hi*b« of pwtanrially ceot«mi*iE«l

offlriiii (a ttriar »o pntaa tin irtegjrtty oftbarapedy and to jwewa hunao
and awinaiiMMal atluiun. The «*H»|fae«sl rwnodia aubpet to
jwtiWS«al eeutrtto fbr CMiin ojwtbl* units of lie California Gulch
Supcrfuad iila will be defined by m map 6aotained m the Lake Count}
Building and Land U*e DcprtnatKt CJeilf md	Ofifcu utd the

AJMaMtfa Office.

6)	Oparabtc Unit 1 (DU3). Thu oparabie am( u Mly deaenbad by the Ef A
Rcaordl of Decmon far OpenMe Unit 3. dtftsd May 4, 1991. GwianUy, Oil J
aaeamfMm *vara! dUTmar skg pda and bJutoric rail yanta, including lhe
Himaotk A*arv* (lag pile and »ponton of ite tad Bah Trail.

7)	Operable Uek I (QUI). Thu openJbto unit it fidJy described ly the £?A

liiootd «fQdws for Opewble Uoit S, dtfad September SOW. Generally,
Ol *1 cornta* of Ac SCW-year flondpbiii ttuu ia located between the Y»k
Water Tnamcai Want and tfac jniat whew Uk gulch taut* the Afteu*»
Rjvar. W«k o# flUi epentile unit wai wmptetal te 2002 iodadtajt ranu
-------
WBIilMI

4ef« CBS MOW 016.SB	,^k, >, n»«. K

Health and 6tndftmc*«i will, provide an Uutid it^oatt witJlio leo (10) 4ayi
ef nswdpt of *« iwrttfeai and *111 me Ism efcfe to swriiase wto
Lmtaww™ 10 provide* timely re»hitwo of thet«Hi»ai. Applicants arc
solely rcjpcwiMe for obtausag wrinec approval from tbe CokroJo
Departant of Mslw Health m) EnviranMS.

2} NwrfJijpneefied Rmbs&S. II stall be n&lawiii) to eunvsi* and m»v« my
earth*, aaatarnia todudtag, butt w* &Rut«S to. art** «Jgt, native »jl, eine
nwae jack oi mine talli&ga Sw da l* for obufa*n(, *iW» upprewrt two Hie Coiorado
DepHacet of fMfekit Health and Eavituoiwnt.

3) fwadty. Failure m pmvidc proof of prior wttfialion and approval faun the
ratarado Department of Public Health aad Environment fcr tt»e protubswi
•comae* It tukjacl So * civil pctehy of On© liuodrod doUarx (S100.00).
Addtdanatty. Hie	w® be feyowwltothe Cotontda Oepartmeol of

Public HiMlfc and Eo.*ii««iwt k> latter frxn tba Luke Coant) iaiMini and
Land U» DepartumR.

B) 0|xraU> U*k$ tt/ fkf Cgtli/orrttei Guicit Supf rjand SM&

1)	Engiaoered Xasiedlai. llahallbeualawflttldncCt.cM)aRnjcltiMonatiiic<,

¦tor «a# the fcMptitt of aq1 tatMing.	or

land, ittduding cmurvciea. «rUn aa «ain««red T*a»edy in opcmMt «nrt I of
tt® Califcma CM St^afrBia Site without prior notification and a^rpewl
two tike Colofiilo OtpafUBOitt of Pobbc HaiJ(h and l^nratanitiK,

Wrioar pwrf of approval few i*s Cotoredo 0q*lo* of PuWat Heajft tod
EnvvooraaM i» a oondttiaD jaeoedact ta iwuaaoe of a btnMiftg permil by Ae
L»ka Can*? Bulkta* atd Lwd U* Utp*ea*t He apptlcaHt raust *nb»!
« mittni requeal f«	to lh« Colo»»#a Depanaiaal aTPuhlie Health

^towhwwffllwjfliaa>f!()r»1Bw County &uU4ins and 1*4 Uk
IXytuiaat, mub *i» oertillod aaji. Tba Calondo Deparwwau of Mrilc
KmMi hv3 Entiimttn! wifi p-ov>di m isibat reapemie wstlua ttrt (10) day»
of of dw nwttten nqueat aad will use be« etRma to coatdlmte with
kadowMn to provide i Sfflely nwluiws. of iw «q«*t Affjlitwlt ire
•tikly nspena^te tor ot»«aig «(rtP,w	ftooi the Cottmufo

OepansMaai of Public Health and Eavxramnou.

2)	Hot»'Baiiii««84 Reoodiw. ti iball be yrtawflil» ewwitf ud pesneve any
earthoi aaiteruda iaditdiim. but oot Usaied to, nativa 
-------
351114	fmimimm

t m CSS R*0.«»»M»

« written rw|*« tot «pprow*I v> 4k C^kmnte Dc^umm of fubiic Health

aol EBWWKMt urtA (, oopy t» the Late Gcnatty IwMmi toi Land I J*
Dqattn^caefaviaoctti^aHiL TteC^tanteDqwttjeni of Public
Heattli mi Ewinwraw. wiM prevkta m jititUd nstjwioe *4as tea (10) dajs
of fHMpt of to» wriiteti «*iuew mad mil uk hm, eflbrt* to oixwllamis with
todowwi k> {mvifie a timely fweMjem of Kit ns^us* Applicant* at*
solely rMfMswsihfe far obteiakig, mitm ffttmti fivm lis Cotande
l^ejairtBMW of INslfe HcaMt aad Ijcvuvaatatt.

3) Penalty. Ftiiuia to provide proof flfpriM notificaooa and ajiprewiJ 6wn the
Crfurtd# Dtpsilioet;*, ofPtdhlic Health and Envtipaaiett for flaws pwbibitejl
activitiae ti aut?p« to * civil paoaity ol Oat BttediwJ deltar* (S1Q0.Q0),

AOditicmeUy, ffae iafiactfcni will be wp«t»4 lo tta Colorado Dcpaitmami of

?'ibi.ic Health sad EtntaaBMIL (9 teo«r ten {be Laks County Huildui g and
t«nl Um tMpHftaMBL

Sactxm S. "He Late County La®! JDwlapnasig Code Secttai 1.3 u totefcy uMoied to *Jdthe
feUwta§ mm wUMaotfoa, 1.2.) 0.

8.2.10. R*»«vinf Svfart Malarnla ar Cfliwimtlteg Oo a* EPA Engiocrrrd of
NM-EHfaaantf RiwAy WWwrt Prior CrtttM*# Department of MUt

H«M an# Ewirfttuweal Approval

A) OftrmUt Vmtl 3 af ** Coiifamlm GuJdk Smftrftout Si*, To «red, caraftvct,
Kecmftia, aMer or modify the faotpnm of «#f building,	cm

UBprowmeoHi w» bod, HKltxittg emvtika, wttus u EPA euguieessl tzote&r
In opamHe uoii 3 of tba CaiMwut Oukfa Swperftnadl Site wittiou: prior approval

of lie Cwtomlo Department of Mriic Hcalik aod EawMimcui.

To moovc any cartta* maicriab nwludkng, but tm IHtaiud to, nab** criii>k unil ( of fbe QaiifoTjsj.fi OiJf h Supcrfiiai Siw wtlbMl jaw »ppr»**l
of tlw CusIbmAi ttepwtiM® of Public HcaMb ami EnvwuoMeut

1*0 cxci'.-ato Ml mnsve any rartiita ELaicriais iaduilAg, buV not limited. 1», OUiv«
dut,oatiw tail, nine ««(• sock « mine teiJjap fiwaiwowwrt parcel of «~.
EPA ge*«a(«o>t< ai in j^iir nweeiBf heW dw H day «f HHHBI

J

K-5

-------
331214	4;0T> PM

6of6 CRS SJOOO DS0.00

Pwiitu B truer
LaJ« Cfluwy Rccank-

ATTEST;

.	lL-

Patri
-------
Figure K-2: 2009 County Institutional Control for 17 Mine Waste Piles Located in OU9

i i rRi rs.; n$«v«

La'-.c .>.Hv

rFCX'EEDINQ OF THE BOARD OF COUNTY COMMISSIONERS

HI I! II ill ll.li IB

COUNTY Of- i..IKE AND S FATE (Si- COLORADO	1183308-R8SDWIS

KESOLl.TlON ZOIl'KM

A RESOLUTION AMKNUING TIIE LAKE CO! AT* LAND DF V'El Ol'VJKN I
CCMJE AMI AIH>1* II INC. KKtiUi^Al IONS ((IMCKHNIX, INS1 ITl)'riO>Al.
(TOil(>l.S FOR SI'VKNTKJKN MINK WASTE FILES LOCATKD IN OPERA BIT,
T.'NIT 9 WITHIN THE CALIFORNIA OUCH SI I'FRKUM) Sl'HT

WHJvKI-.AS. tJic Bnud of Ciwnty Caromiii^aneH of list- County of Lake. Stetc t-f'
C^iuracb ("BtsnrJ'i, is veto! wife administering we iifTrtjis uf Lake County, Coluradu, ptitiuittit
to vac: stn. M:in:!iaridK. and lixplomlkia of Significant Differences t'ESD) ihjl require
LiiiUtuliuiMJ c-oalru'Iii far ihc Califunsia Quidt Supe.-ftuttl Site tksipiicd! li> pievunt cunlititiitwltid
s«K from being handled indppr.ijiriaiely, ant! U: a»tst the hPA i- dclrhrp the California Ciuirh
Sn-perniniJ Site from the N.ttfonal Priorities LisifVPI }.

WliLRI-Afi. because i>jc EmsnO.rr.ml to "Jw I,IX' was- initiated hy the HtiarcS, no

application ire was required Sn be paid; and

WPFRKAS, ll.u Luke Cuuirty Lawd DcvvSn^c.etit Cink" duvs «pt cunvnil* ci.>tit»U'«
pRsv's'itni esaWishinyi irfrttuiiwrwl corr-iot* furor w.drrn Operable Ur.it1), and

Will Rl'AS, aa airendraent tp the Lake County I and Dcvclrpmen: Voce is necesABf> u:

ucid standards of review urii ik'tlnriora periaitiitig ti_* institutional '.'JiUioSi fur tcMiniesn lti'me
»v Ltuid Ust Departfiiilil «Jut the Pkritr:^ i\«rritMNiitliues aad

ulhci piuviiiciti yf tlic Lakt Couitly C^pieltciiiiitf FIlui xyd the Ixid DtfvtjoptQUijt Cudc. aiw
-.ewvaw) Hec«i*v of ch.trtgi;ig sosial vaiiiot, new plwr.mg tcuct'pis, or nflw »«ial« ccwh^ii;
conditinrix *nc1 w'i prnwotc -nc public health, ssfcH, anJ get:era[ weltaw of tltc citt?ct3 of Lakt
County.

NO* 1 KKRWOKK Hh I'I HhSC5l.VKDtli.it:

Smioji 1, This Kcsuljtwn .s corts:stcni inlh the goals, i>bjt*tu\t.'S. poiicia and othc; psuvisiuj.s
¦jf'iw i.nkcCminly Comprchenvve ?tari «rd l.arni Itevt-Hftnen: Cisk.

Section -¦	Kcsiil'a-.wn ts is«ct.'ssur>- .••ecau.*-; of"	sociul valuo, p:>uniiitg

winccpti ana crthrr %oci*i cjhJ ccon««nit iMmiitwr1;

'1 li? RsiClutiuji & iuuiJ Il» piuKOTC lin- pJjLk' !;s.'ullit, swiftly .u-d gcttuRiI wdfait;

^rcSicti -1 l"hf Lake Cu'inty Land D^veki|m:ent Code Chapter 3 2 ts ht'rby ametuJ^c to jdd llie
f jlk-wtjig i»i.ng,ia|;e.

3.2,1. A) The List smiicikt skdi be acicnccd 3? follc-Wir

K-7

-------
lllllllllilUM

Vi no	i "'i "''i p* .«»*-*«-

-:r%S RV> •) x ;(>	«iri

'1 he purposr or'there ru^uJaliom- n to tvlaBlish rastttulkjM. consols In meet the

i>f the v.iSios '.-PA Recnrd< r f TV-Vision, Action Memoranda sr
1:,S1> lhal require inSlifuliotM1 egalrdi, :o tmpiemcr.t requirements desipned t;i

prevent contaminated soils tecs be-in# .'u-rxilcd inappropriately, jur.J in as? i;i I f'A
in deleting the Sin from the Xslinrul P-inritics I is.1 t'NPL j

:>'! Definitioni. Shall be artmtfcd "o include the following:

S; OytaaHe unit 9 iPPj); Operable L'nit <> ;r^]jdus tlx>se pert.wis .,>f 1Lc
Gull'uttui Giildi site *1w? the laid use ii rcsidsr-Uiil w Out jit* unit tf.lv

invitee as residential. populated areas and ® low-density res.dtMMu' hutm.

3.2.2. UctI Management Practice* Informational Handout. 'Ihc first ^-nUiii-v -.W
In:	as fulbWi.

I	ua:h	m it (wiling pcrcni wit kit Ci c Kxmdwi« of Gpc i ybl ,• Unit 3,

Operable I ml S xid tlx* sewnWn rkiir wp>te. piles in Operable Unit 9 of the
tjulisornia Gvdch Supra fir*", Sitt. will '-vr |-.nn:ilrd w.'.r, .i Han-toil 1'n.^r. the U-it

t'nutty Ifa-Jcm/ aa? t itr> 1114" 1 »t rtmcttl Tcgnrd'.np Hc« Management Practice
tf,.| managing potrnl ally c.i nir;n«j *a'l* i.i 1 »Ve f fn.mi\

J,2,3, lustifirtiuiiHl Control*. Shall he amcrded :c. include the Tbltowmg:

C. Se\pcrih.'c Umt 9 "itie Sepleiaber »UiW LSU documcr.ts tll'A's dr-rNnn to
itstiiie iii.pcm"*>lc
I.nit« flji l»\c «ib >t: the wftx tfwt itm rnda llrf ISwtt pwo "rad w-kwiiti ii
utile. k"ii"l bu! hnvt IijjJ cwntck'niiuiliim 4t Jvpii tbiU	tltf

c«idi.atiaJ jead actiur. d EFA slcsi^twlcd tit? swventc™ nun; nu'c p;.Ci
cngiticered icrnedics in the HSD EPA has prepara! a cinp ttet L-.eniiiies the
swifsr in i.«" pi!f. Ihnsc pj.es are idcntif.ed as nwinieis 12. 1 i. !8 710.
21 J1. 32. .U, ?4, ?« 16,207. Uv, -,i I, ",9 4„j 341} r,m imp w." be

liKMifJ :n ".He l.iskt: (Iiiijnti Hnildinn IJepjrtmwi;, Clerk said	t iliirv

snd A.v.KSftT's Dtlkc

2} Euiliijcifd Rcmcdi_•.•<. It ibr.li be tinljwii.l to erect, construct, rccoiistnajt.
liter fit nto4ify the te^itpint of any building, strucim: or improveraeri1; aa
Unrl. Hk-lsding «ca\'stinn, within ar crgincersd rmtvly in Opf-rah".# Uit:r 9
of the California Gukh i*»fiefft;od Site *'ihout prior r.3',ificatior. mj oppro^ai
trnn the tMwado ilepiulira-nt uf 1'uHic Health itnd Iwnmimcnt

Wj,i(\ctt pit'uf uf ttpptX'vnl fiont the rr>kn»vin Ofpailn^ii: of publiv Ke&Wi ja-j
EnvitvPtrfiif is, u cattdiii.tn :vt:cedc:r. tn	uf .1 h.iUing pcruiil t>y the Liikc

Ci.iur.ry Bir.IditJf Departmeni *lhe appltcan: mttst submit a wr.ttcn	tbi

.ipp:uviil to die Colorado Dqiaitweur of Public ]I«dlii wid Envinxtnicnt vntlt a
ropy 10 the I act t'nmtx Ih ddtr.f (>rpnrttntxt. each via err;tied titsil. "1 he
{?nloracn Dcjiartnwmt (it Public Health and Krtvironir.rrr wll provide ar, in it Mi
respurje Cojrtpriscd ot the scVnowll<\Jgntrtt of ihc nsjue&t artel Unwline and
pfitmiia! 2f?i"i:ts needed by the applicant for successful corap.ction of the icipjes'
dctcrrrtavriiw Afpiicants. arc solely rcsprretrblc fnr ohtaininp mriitnt ipj-tw*:

(•on the Colorado !>spiiijtrri:nt uf Puhlit liunjlh strsl Eciviron-ruTt

?Penalty failure. :>,» ptf>vic5 proof nf prior rtmtfiunra and approval ftvm tjic
Col.-jrsdo .')cparti3rtr. at Public 1 lualth and linvirDnmrm tor these prohsbitsi
itrtiviStt i 'tiNcct in a c.mI penalty ct'Sl Llti.OCI. Addtf.onally, the infraction
mil be reported tdlhe Coferad;-! D;p*r:na'iit nf 1'ublic (Iwlth diid l'lnvif'.>ttT,i:iit
hy Icrcr trim lac Lake Ccunlv Iluiliiing IX-partmcrt.

2

K-8

-------
353410- I2W280M:. nt	-s*m

3 «p CHS mm OKI :t.	r,«*e** k-u-jr

Sccnrci 5 "The Lake Cclintj Land Derekprcwxl Code See'.tur. 8,2 '.C is .tctc.-v arnrr.ded lo
,(*e tolk:.«TKp.

Cf ItperwMf Itiii S> of the Ctfrfonrim CuUk Supeifund Site, Mum H'mte Pikb, J r
crcct. contract. rccortnrxs, iter oc rvadity the footprint cf any bo!d;rrr;.

structure ot unpKwemc.it> ur Sand, ir.dLdnji CMSivurini, with:n sr. f-PA
etitiiiawrw) lemcdj ;n Cpctabk Lhiil 9 uf (he Cdifornid Gulch Superf-md Sitt
wiikut prior approval nf the L'oJuisdo Department nf fnblR I'ea'th and
Lnvjrixur.cn-.

SfylMji f ihiis Rciululiu.-. ihaJI fccinr.: effective -ipoj. its aic|rtUifl

MOVfc'D. READ AND ADOPTED by the Board of Ceutty CoKiniiSiujiKS sf uc
I'-ounTv of like. Stats cf Colorado. at itf. irgukr meeting held the 7 J st day of Dwosntn'i,

UUAKDt)! COU.M i C'O.VIMISXIONLRS
LAKJt C OUN TY, £ OLORADO

a

Kenneth 1 . Ulsm, Ciainnar.

<2~e/:

Carl F. Kcfcauiei
Mizuc Kotttagm /

ATTEST1

p v."-*

* A,

I a'k'i* rcr.rit« neffl;
fir's lr lite Bvwd

K-9

-------
Figure K-3: 2010 County Institutional Control for OU9

PROOKKOSNGS OF THE BOARD OF COUNTY COMMtSSIONEKS

COUNTY OF LAKH Af	t.ORMX)

'A!

RESOLUTION 10 /:i

L

A RESOLUTION APPROVING T1IE LAKE COUNTY COMMIMTV
HEALTH PROCRAM PHASE 2 WORK PLAN TO SERVE AS IIIt
INSTITIT IONAL CONTROL FOR OPERABLE UNIT 9 OF I UE
CALJFORNLV CILCH SUPERFUND SFJ E



WHEREAS, on September 2, 1999, the U.S. Environ menial Protection	¦?-£

Agency (EPA) issued its Record of Decision (ROD) for Operable Unit 9 (OU9) of	f *"

the California Gulch Superfumd Site, which selected ihe Lake County Community	|
Health Program (or "LCC11P") as the remedy for OU9; and

WHEREAS, in March 2005, performance standards set by LP A in the
September 1999 ROD for the initial Lake County Community Hea'th Program
were met, as outlined in the 2005 LCCHP Annual Report; and

WHEREAS, EPA, The Colorado Department of Public Health ami
Environment (CDPRK) and Lake County determined that it was appropriate to
continue certain functions of the initial LCCHP '.o serve as the institutional control
for Operable Unit 9 and tu continue efforts to reduce risks lo resident children from
exposure to lead from various sources; ant!

WHEREAS, Lake County developed and CDPI1E and EPA have approved
the LCCHP Phase 2 Work Plan, dated 2009, which sets forth the framework,
structure and administration of the LCCI1P Phase 2; and

WHEREAS, The LCCHP Phase 2 Work Plan transitions LCCHP
management responsibilities from Asareo and EPA to Lake County and CDPJ IE;

and

WJIEREAS, the Board of Courtly Commissioners has carefully reviewed the
provisions of the said Lake County Community Health Program Phase 2 Work
Plan. (Exhibit "A"), and finds that it would be in the best interests of the county
and its citizens to approve aiui to implement the same; and

WHEREAS, the Board finds that it is authorized to approve said Work Plan
pursuant to the provisions of § 30-I3-101, C.R.S

rVj* 1 J

K-10

-------
NOW, THHRFFORK, BE IT RESOLVED by the Board of County
Commissioners of Lake County, Colorado;

Section 1. The Lake County Community Health Program Phase 2 Work
Plan, a cops' of which is attached hereto, be and ihr same is hereby approved bv
tills Board.

Section 2. The Lake County Community Health Program Phase 2 Work
Plan will serve as the institutional control for Operable Unit 9 of the California
Gulch Superfijnd Site until such time it in determined that the LCCHP Phase 2 is
no longer needed pursuant to the process set forth in the Work Plan.

Section, 3. This Resolution shall become effective upon its adoption.

ADOPTED this

of	j 2010.

BOARD or COUNTY COMMISSIONERS
01 LAKE COUNTY, COLORADO

Michael J, Bordogna, Commissioner

Cleric and Recorder

Lake County, Colorado

Ex-officio Clerk of said Board

Pag# 3 rf 3

K-ll

-------
Figure K-4: 2010 County Institutional Control for OUs 4 and 7

I i

1261464-KB

fa"*™ pps™ _ jgass--'

PROCEMHNCi Of 1UK UOAKI) Of COIN '/ Y'WMMlSSIClNERS

county of lake and state of Colorado
RESOurricw 2»ie-Si

a smmmm *meww«i the ukb countt vmwmxpwm
"COBB AND ADOftWO'.*i(WU.HOM# CONCBKNMO »fll|«ri«M.CWip*S
,«* owaAiie wit <  Ijmd Dmtopm*4S«fa fWC} bt Mnendei to
ijttja ihe mmliinareafto of ihe «tmt* Eiiyir«manl«J huleaiaii Ajtusy (EPA) itaiii of
Dttimui or ActoM Mcntonusk Owl rebuilt utttiimiunai M.itofs for the California Oukh
Supcri«s S'.cc dev^ucd tu prevent wrtaiiluMed »Ua foam Uu* fondled irwppiwmtrtely, mi
to aadil the EPA in iMttiBj fc tulifwoii Gjltb Sepetfuod Site iwtm. Ifee Httiami Kadlis
LiilfWM4»

WHEREAS, tortus? Bit wnendraaiJ to the LDC una jnltiwed fry the Ro*-d, o#
tjipliestttn fee **i K^uiitdlo tepsM; and

WHERKA5, Lie Ub County tj*»l Devetaipmett Code doe* ft* emmay contain
praviswiw trndwivms irttuas.eml tnntJoU forOpefthle Ur.il 4 wrf Oj*r*bit Until ?; *nd

WK6REAS, a# icnewiaMtK 10 the Use Oowy Laud Drtdupmet* Cede is BMeaittf tu
add starsknk at rrr'rr*. arid ctefwiikiffii fwiaouug ss tajfatutiusil Mttmh far fee CaWormii
Gulch Suj*tft»d Sire Op wiSfe LViif 4 »«f Operatic U«i ?; sw«?

WHEREAS, »J* Luke Gnuoly PteiM# OaMniswiiD wd fte Ikwd of Court}-
€>irr.iB»»at3Bni trald < ;,«! publio fc®rir,§ oo this natter on the 11*4 toy oi Ifcwwter, 2010,

KM

WHEREAS, II* S*c*rl of Cwatty Cnounjaioncri to ewsidrred ihe TewTMtwniJations
of the Lake f ouol) Land l>'» DcpartuwH! rtnd tic Flanauiji Cocnmuniwv wild

thf I'oani nf TyiUlty ( untnu^u'ififrfs fiiidH th«t 1he f&rc^uir^; urot-ndtit^nt*. Ii«

Uk Ijrite Cuutly ljK>i Drwrtopiwcii": Code ore cwiaistcni wi1» iht gpjls, oJfestfves, p*cicj ins
nlliw piovisioo uf tte Lite Cowrty CnmiwJMUifflve Hart mk> Si# Iml Pnekiprwru Coit, tee
bct*utc o( efciflpng »«!») vrfues, new pUnumji euwqMs, 
-------
>*c miemted to meltufc ihu Wii.winj,

f, Opmkli Unit 4 (OW): Th« rpevaM* anil is fi.I'y iffjcr bed by rtie EPA
ttotai of Decision U* Opcmfcie l.In>t 4,  cnnlaiw fluvii] liiliagi ad wistc reck files. An FSD
ptL-jMBtvU. b> E?A m 3fXM exemptnJ the 0® Cily.Tfuvai tailing* from the
JS.GO,

I*. OpMnblt l)»il 1 (Qtn): thin upcub'* wit >i fell) ifesciitai by fte BPA
Sesord of DkMm kx Optrabic Umt ?, ik without ft! ®f toii:feiii0S3 luJ iqppnrvi! fr&na Uw?

©(tott® Denton* «r hitlt (Mb «ii Smboanat

WftMea ptwf jf Mppm-al f»« to C«1o««So Uep«wn«s« ef Public Ifeatt	i» *

o^ttf* )R«e«taiit tiM eft MMbig fndt ly'4w tdet iwtMIng D«|Mntnmit

Th£ ftppiii^iti muM subsrJf. a wtittntx ttifutM & jfifniviJ to the C-oldrsis Dtpzctmoa! of Public
IftaM toi Bivuoairiet *,f«Mkiri

mail n* Cokwwtn tkj*rt**nt of PuWk He^tfc mi F/ivsortacu -will [wMt m iwisl
within 10 d»js of ntfl of the written ifquet.1 and will Has hcj efforts to ojonEmitc
Wita liuHk.*twT» w	• Wiady jbboMIusi of Ibe r«i-i«sl- Afplierati are s«telv resjsMnibte

fcf •bwlet hhMW l|yi«wal iwmfc Co!rt«do DepwttenJ of Pubk: HcaMt

I.	Rmrdln. h«»3b» imliwAd Is tt&Mtt and reno»c iny einhn

MMMl Mill* hit wk liiltelWiMiwB Jirt, niaw »t, tmm waste nA« «lue
ll^jy iglll *> (IIIIMI	« SPA. nan-nwpwed nmnlyfc otecm of 10

proviki bufa the Coioradu U^j-orwriCtU of HeoiLH mtd k.ev>tt)anuC3ri.

Wri no* proof of	turn thr Calondp ttepurlmtrU of PtAJic Hesltli gad Envirnnmrat it a

Ooiklilioo jireoedtmt to touexc uf a huiiditl# perwjt by liie Lj*£ CqubIj t«uijd«fi 15rp«rtr«nl.

Tb» »pl"mm .psisi-wtaiirt wiflHi bs(ik«i, for	to 'iw Gflteiie. Dqwfe««t ef.|«lile

HMUi'Mut ftiriwonwni wlli* «py »tw l.«k« Cwiiy flonMin^ rteimnmen), each
wait. IT* Ciik»4> DBparnotnl rf fuMk Ifcsllli and linHronmen". mtl pnmsfc an initial
tafi-xxw wilMu 10 
-------
fSf1 Ctm	™ 		

& fiiwUlV M#i la pevtfc pwfrfpilKiiiiiWiitfn	Ami a*

tTVii!i%l«Sri4.i% ***»——mil" urn „,. | -JT IJb.Ll J, U^mU'A ds.w,ji 1* - - -'' - W-..I......> .-...j, &£.*,	>...»„ >. tau.»... -g .. .a,.*1 .	>-

m jnww rmmm ana ewsifftiSWflil lot WOP |wl«W ««ivgtM» m
»tdvl pond* of IWft* AWbmtiy, ita Mmtom	to fe.

fliihutt/lfl ftrrurtrnml rtT PSiWi^ MVohh a. Jl	V, £.*ii»r ft***. »4x- I

; ItPMIf lr%(pi'Wlrala"wl W* I Www	JUSIm CsX3 wl#»*«lHUKI"l. CJr ^SbUU li£^*3 'Ufp^ wWlf

£	ffiyfe* f~ CMpfcFiHfai!' Cb&JL	fTTu',

l» e«jtjw*r*d RctMrika

modify LV footprint er n,i, builAfl,, sinciwe or imrnvnaaritoa mdud*#

^*^t''1? of tihc

^ ^ j> 1 o^ni RjLnihniv* fwirtr n-^iSfl « "" ' " ' "" " " • * - — » - —	- •

?$**-'<.»« j-*i I'M* .M3t"%a sj'vi

„ jT Proky,^ -tt«S«(Wk SJX.4 K"il li *fif mil- iiii-hDii inT

%Mi trupwK FimmiM TSmf «M¥3OT0lIitM!L

cjwfi-joe jWB»(k*M 10 tuumrc of » biilding pnwut h, ih« Uto County fruiting ENsjwrtBieiit
Ike applicant lousrt mtait > *»ii«Kn Mquat (at	lu lh« Celan**i UepsrttwiH of PuW.c

Men* md EovttMBMM will» copy toth* 1 «$» County Building BejurwtaR, t*ch v>» etttified
mail. The Colorado Dcpaflitnsnt of r*fclic H«*lth «sd Environment will provide aa nuilal
resjmtje within 10 cl> ipafultwrffc wtjtiesl 4wfaMri» an i#l# w#ttaii»fe

'fSw sAislaAs# TXifrtf J- I>«\i1f»~ttiai«l; IRgLcifij iuii ¦<>%&,	T8! ¦¦1rin,-«* iiAi-irm'irrr ¦!¦ .ukl"®! JsK*' l,»-n«>4, -jJ f*-».. ,n1.n ... rn3.

^*	-li "•'»«*» '^PP * *» lIUul Uw vtWJlsuu i^^AilQSCui 1?J	Lirf

'"p ag	y—yi—-^--^1 *J| -|™-	|| ^L^*, M 'iy. - |t^ttl8W|5,|	, L4,-L-jLl-Ji. J| liVl'l -I,. I IJI ¦fly i^u _ III iLMIU'l'iijiJlL

'	' ««--*>» W^BaB w*f-	^s.'i'H. ¥Aff»9«vi> "ijif-Sal al:SiV ®

mntcMii iwSarling krt «rt hmiied to n»ti\* «rt, tativc noi!» mint «mm art «• wfee
IMSu|»k tmacH of i 0 mbk >wh ftwn w EPA aon-ngsntavi remrfr in Openble

1J_|f "jf'fflgjji*iWfB fl||j^VWl|j| /^|||k1l	J ^>r^_	_i^ _i.Tri^I'rs'Wl ^h» '

Wna«» poof of ijpoml ferni the t:«k*»5o Defwnaiew or PuMic ttenl* ind EnviawiMtt ii »
cuMidium fIwtfal to J5M«ce of a lKifldin» j»raill by ifct Lake Cbamy Saikkng IlcfartaKiiL
Ihe »pptic®n« nut icwat • wilitoi	far ipp^iv». » fe Cotorado Ofjjtrtotnt of Mbc

Br 11	A TOpj 10 (hfl I Akt	(jujijjjj iJtjiVlrimi, 'rtV Ii ^ iv LcAsftttd

™u Tfc. CdoMdo tkp«fta«,s of p.ihhc HHhh «ad fcriwMM 'wfli po* m k*W
wtpoiss wishia 10 iwyt ef tsetipx of Uw »rmen nsjues twd will we bes! effoils to wen#*

Itil 11 i ^ -'i"i7ii r^ii'ii'ii'T' i "i ii 1 j'-1 ">i|i ii -^i i ~t m afe fj*^. 111	¦ in mi |, %•- .-t -t — -,.	'ife' -			^ -		 U'i /•_ f ^ ^ ,.. — — ,- — „ Si, :i .„

ismcjwwre kj prtmoe a Ds^fi^ resowDOR y-i ihc ®|WSi. /^fKiiJOti *r« WKiy tttpofftioM

ft* tfMihg w#tw «Kwovri twn'dw.CS6bmtti»	af nUie'HipMi mi HWwoiww.

J*	F»l««'.» P»w* preofcf pnot waU0e«.i>n «td sppiov*! fmfti dw .

^blrff>i4n	Hct'iki Eovis^njtiieiit fot tlieac ptu^bilcd atiiviiiiai i-%

iMfepc! to * civii pciwiji	At)ditionill>. the ialmiion %ill be reported lo flw

OIbi*Jb D#ii»iw#rfl*fc Moiiiaaif fcrtreamenl by tana froa lit Ld»
Ccwi^BaUiaitDt|MlnwL

lUs rr iff rc\	M "*T"'n f?i, -fr ir-"- i-n ¦«1	v n fl w	. I, nn^t' ~'i - --. L 4-^^-	f^i,, iig- ¦.» »

IA upcfiOR ubk i» locnxv Lwstruct, r^nru«rsici, wtcrorWio^ly tf»WXJl^fifiS 01

|f:HSk^l

jTt.limt'Ju-iii-i ''rnimm^Tr *m iOiinr~TJi1lriT r- ,,.> ,J*.- k,.-  OpnUt C«t* dT M'0#fiR(k-Q

Supsrftnd Siw witoi pier »ppm«i rffc Csiomdo nvpwtmxn oTPukiit HaiUi

Eo'vifQiiiaeii',

K-14

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V.N * < R* RW 1-W1

l ^n< > P"T?»

i 'ir K iUiL Hf*

E. Optrmblt UnM T. "S'O awl, cwsuwai, raaotairjct, alio «¦ mbdif}' the footprint of
SJiy traiWmg* St^urc w mtpruVTrneflt'ji Oft jfiL-liidrfig r*uavd1j^n, w?1hlr» flf EP'A
eajpfteerea rtnctj in Optarabls Dint 7 of At Cwiffur a Oukfi Kiifwfural Svi* withnm
jkrfot «ppra% si of the €«lotade Depmmenl al' iVWk We All am! Kootrvnmat".

To ttttm't md rcmc*i say iwthen materials ificJodiog b-jr.not limited to a»n din,
nMiw toil, mtae wcttc fftck it mine slings from the o*aart paced of ui EPA nw»*
w.giocottl remedy In esasaa of 10 caftm -jarfa in Oprrabk link ? of ttw C*)kff
Cmtnilv nf l.akt, ol" CoJarmJo, al il* regular mating held (he

¦OA»ar««JHfycOMMlBKW»S!

Ctaklfi'lta Bond!

4

%

K-15

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Figure K-5: 2013 County Institutional Control for OUs 2 and 5

S6I199 4.*1 s. 2313 1,20PM
1 m S Chs RSOiX; P$0f>ri

Patricia. Hirger
I jkr C imntv

PROCEEDINGS OF THE BOARD OF COUNTY COMMISSIONFRS

COUNrY OK I.AKI. AiNi) STATF OF COI ORAIM)

RESOLUTION 2013- ,/J

A RFSOI.I "HON AMKNIMNC I HK I.AKi: COCNTY 1 AND DFVFLOPMENT COHK
AND ADOPTING REGULATIONS CONCERNING INSTITUTIONAL CONTROL FOR
OPERABLE UNITS WITHIN THE CALIFORNIA GULCH SUPLRFUISD SITE

WHERP-AS, the Board of County Commissioners of the Count} of Lake, State of
Colorado ("Board'"), is vested with afainistcrittj! the affairs of Lake County, Ccsio»ac\ pursuant
to state statutrs;

WT [FRF AS, the Boanl has ir.itksU'.d n Land Use and Do element Application, file
number /J?- , proposing that the Lake Coimn•• Land Development Code t"LDC") be
amended \o meet the requirement', of the various hwhwaneiUal Prelection Agency ("H'A")
Records of Decision ur Action Memoranda that require institutional controls for ;hc California

Gtiidi Superfund Site, designed to prevent «.'a:uam!ruHce Department and the PLavmsg Commission: and

WIILRl-'AS, ihe Board f.nd.s that the foregoing amendments >.o tl v- E PC ;,n* e-onsisirnl
with ihe goals, objectives, policies and other piuvhbits of she I.ake. Count)' Comprehensive Plan
and the LDC, are necessary because of changing social values, new planning concepts, ps other
social or economic wnuttiiom; and will promote the public health, stalely, find gcrmrat wclfcn* of
the citizens of fake Ccu;riiy.

1

K-16

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361199 *LV2MJ 3:20PM
2 of 5 CRS RSCOOOSO.OO

l'atifia fitter
3-akc Ooutv

NOW TlILi RLh'ORLl BE IT KJLSOLVLD that;

Section I. Hi is Resolution is consistent with the goals, objectives, policies and other previsions

of the Ixikc County Comprehensive 1'ian, unci Ihe LDC.

Section 2, This Resolution is necessary because of changing social values, new planning
concepts, or other social or tcunotric conditions.

See lion 3. This Resolution is found to prompts, public health, sefe-ty, and general welfare.
Section 4. The LDC Chapter 3.2 J (D) is amended to add the following new subsections:

11.	Operable X'nit 2 (OC'2). This operable unit is fully described by the UFA Reco:d of
Decision for Operable Unit 2. dated Sep:ember 30, 1999- Generally, OU2 encompasses the
Malta Gnlch drainage, OU2 was deleted from Lhc National Priorities I.isl in June 2001.

12.	Operable Unit 5 (OUS). This operable unit :s fully described by two H'A Records of
Decision for Operable Unit 5. dated September 29, 2000 and October 31, KMX). Generally, OU5
encompasses the AS ARC O &ncitcr/C.olorado Zinc-Lea; Mill Si:e - smelter sites around
I.c.acvir.e Hiid one; mtll she. The smelter kites include the LGWA sites (Elgin Smelter.

Grant'Union Srr.elicr, W;ilcm Zinc Smelter, and Arkansas Valley South Hillside Slag Pile) and
die AV.'CAL sites (Arkansas Valley Smeller and Colorado Zinc-Tead Mill).

Setijyn 5, 1'lic 1 .DC Chapter 3,2.2 i> repealed and replaced with the ibllowing;

3.2.2 Best Management Practices Informational Handout.

Each applicant for a building permit within the boundaries uf Operable Unit 3, Operable Unit 8,
the seventeen nine waste piles in Operable Unit 9, Operable Unit 4. Operable Unit 7, Operable
Unit 2 and Operable Unit 5 of Ihe California Gulch Supsrfund site will be provided with a
foeuM'Wl from (he Lake County Buildirg Department regarding Best Management Practiixa for
managing potentially contaminated soils in 1 ,ake County. Each applicant will he obligated to
sigr a document attesting to r.he fee* that hs'she has read and underpin*! the Utkc County Best
Management Practices handout. No building permit will be issued without the applicant's
written acknowledgement provided to the County.

Section 6. The LDC Caapln 1.2.3 is amended to add the following new subsections-
F, Operable Unit 2 nf the California Gttfek Super fund Site.

I, Engineered Rmwlia.. -It slia'l be unlawful to erect, construct, reconstruct, alter or modify
tTc footprint of any building, structure nr improvements on land, including excavation, within an

2

K-17

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. iiiiiiiniiiii

361199 i-i5,-iDLJ 3:10PM	Patricia Bcigcr

1of1 CRS RS0 00 DSfl.SI	Lake County

engineered remedy in Operable Otiil 2 of the California (julch Superfund Site without prioi
not! Tuition ami approval iron ilic Colorado Department of Public- llcallh and Environment

Written proof of approval from the Colorado Department of Public Health and linvirorjmeat is &
conch mr1 prei'ctknt to issuance of a building permit by the Lake County Building and Land Use
Department The applicant trust submit a written request for approval te 1hv Colorado
Department of Public Health and Environment witn a copy to tlic Lake Count>¦ Building awl
1 .and t.se Department, each via certifier. ntniL The Colorado Department. of Publu: Health and
Knvironment will provide an initial response within ten (1U1 Jj\
-------
Illllllllliilllllll

16i 199 4-15-2013 3 30 PM
4ct5 CHS KWlfl mo00

PaL-.c:ii bcrstor
Lslcr Cc'_nly

Written proof of approval from ihc Colorado Department of Pi.blit: flen'ih aid Diviroruneril is a
tondhior. precedent to issuance of a Voiding permit by the Lake County Building and 1 and Use
Department, I'he applicant muss submit » written request for appro*. al to die t 'olorado
Department nf Public Health and Environment with a copy to the Lake Count)- Building and
Land Use Department, each via certified mail, iiw Colorado Department of Public Health ami
Environment will provide an initial response within ten (10) days of receipt of the written request
and will use b^.st efforts ",o coordinate with landowner* to provide a :imely resoiuNMi nf fie
redes', Applicants arc solely responsible fur obtaining written approval from She Colorado
Departmeivt of Public Health and hnviroomerrt,

2.	.Nob-tnginccrcrt Hciaevlics. It shall be vjilawfd to exeavaie tuid remove any earthen
materials including, but not limitedto, native din, native soil, nuns waste rock, mine tarings,
slag, flue ihiM, smelter waste, resident!h1 area soils acd non-residential area soils from the owned
puree! ?.n EPA non-en fnnecred remedy in mxus often (10) cubic yards in Operable Uni*. 5 iil'
the California Crulcb Superfund Site without prior approval from tJie Colorado Department of
Public Health anc L'nvironmcnt.

Written proof of approval from the Colorado Department of Public Health and bnvironnxat i$ a
condition precedent to issuance of a building permit by ;ke Le'ce County Building and T.ane, Use
Department. Tlbe applicant must submit a written request for approval u? the Colorado
Department of Public Health urtd Environ merit with a copy to the Lake County Building arv;i
Land Use Department, each via etrlificJ mail. The Colnradu Department of Public 1 teal'.b and
Eiwironnicnt will provide an sni'dal rcspoivsc wi'.hir. ten (10) days of receipt of the written request
[ted will use best efforts to coordinate with landowners to provide a timely resolution of the
request. Applicants an: solely responsible lur obtaining written approvtit from fie Colorado
Department of Public Health and Fnvirnr.mcm.

3,	Penalty, failure to provide proof of prio- noli Heat ion and approval f-orti die Colorado
Department nf Public Health and knvirnir-nent for these prohibited activities is subject to z civil
penalty of one hundred collars (MW.CW). Additionally, the infraction will be reported to the
Colorado Department of Public Health and liTivironorat by letter from Ihc Lake County
Building acid I .mid Use Repiinrner.i.

Section 7, The L-DC Chapter H.2,10 is hereby amended to add the following new subsections:
F. Operable Unit 2,

To erect, construct, reconstruct, alter or modify the foot print of any building, structure or
improvements on land, including excavation. within an JiPA engineered remedy in Operable
Unit ?. oflbf Onlilbmu Gulch Si:psrtlind Site without prior approval of the Colorado
Department of Public Health nod Hnvi wnmcti!

4

K-19

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361199 4-IV20IJ3 2nPM	iHi^mBeracr

5 of* CR3 K$0».i Dtoi'D	Lake C't>jn!y

To excavate and remove any earthen materials including, hut not limited to, native dirt, native
soil, mine waste rock or maw tailings from the cn,\i»cd ptireel of an EPA non-engineered remedy
m excess of urn (10) eubic yards in Operable Unit 2 of the California Gulch Supcrfmd Site
withe u1 prior approval of the Colorado Department of Public Health and Invuoiirr.ent.

il. Operable Unit 5.

To erect, construct, reconstruct, alter or modify the foot print of any building, structure or
improvements on land, including ewavatwin, witM« m EPA engineered rcrr.cilv in Operable
Unil 5 of ihc California Ciuich Superfund Site without prior approval of the Colorado

Dcpar.ment of fuhiie Health and Cnvlrrmrneril.

lb excavate and remove any earthen materials. including, but not limited to. native dirt, native
soil, mine waste rock, mine tailings, slag, flue dust, smelwr waste, residential area wils and nnn-
rcsidi'tilia! area soils from the owned parcel of an E1PA ram-en gioifred remedy in excess often
(10) cubic j'ards in Operate Unit 5 of the California Gulch Superfund Site withu.tt prior
approval ofrhe Colorado Department ol" Public Health and Environment.

Section 8. This Resolution sha.Il become effective upon its adoption,

MOVED, READ AND ADOPTED by the Board oT Count)- Crtmnisshincrs of the
County of Lake, State of Colorado, tins _/j" "clay of _ _	,„!(?! 3

BOARD Ol COUN IT COMM1SSIONKKS

. ' • *	LAKE COUNTY, COLORADO

ATTRST:

C		" i	it-vw'-	

Patricia A. Bergcr. Clerk and Recorder,

Lake County. Colorado; a officio
Clerk t« I he Bonnl

5

K-20

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Figure K-6: 2013 City Institutional Control for OUs 3, 5, 6, 7, 8 and 9

CITY OF LEADYILLE, COLORADO
Ordinance 3, Series of 2013

AN ORDINANCE OP THE CITY OF LEADVILLE, COLORADO AMENDING THE LEAPV1L1.F
MUNICIPAL COM AND ADOPTING REGULATIONS CONCKRNlNf; INSTITUTIONAL

CONTROLS FOR THOSE PORTIONS OF OPERABLE UNITS 3,5, C7,8, AND 9 WITHIN
THE CALIFORNIA GULCH SUPERFUND SITE LOCATED WITHIN THE CITY AND SETTING
PENALTIES FOR FAILURE TO COMPLY WITH SUCH REGULATIONS
WHEREAS, pwsuant lo the Comprehensive linvtronmenta! Besp-onse, Compensation arid 1.ability Art
("CERCLA"}, 42 U.S.C. 96Ci, eI scq, aod the National Contingency Plan 40, CAR. Pan SOU, the U.S..
Environmental Protection Agency ("EPA") has sefecieJ miwetlici fur the various operable units ot the
California Gulch Superfund Siti; ("Site*) where EPA h*s determined that institutional controls are necessary
as a supplement to engwpctiag runt rots, 10 manage waste left tn place.. to comply with applicable State
taws, an J to protet: hunaii health aiid tiie environment; and

WHEREAS, certain operable* timts of the Site. spi-dfirally operational unics 3, 5, 6. 7, B, anil 9 lie
pai iialK' within the boundaries of the City: and

WHFREAS, the Hoarri of County romumttonrn of the Cuuritv uf Lake, Culuradu ("Boanl"). previously
amended the Lake County Land Development Code ("LOC") to meet t* if-tniiremertts of th» various EPA
Records of Decision or Action Memorandum that require Institutional controls for the Site lo prevent
contaminated soils from being hancUed improperly, and to assist the KI'A in deleting the Sire from the
National Priorities Lisr ("NPl.'): and

WHEREAS, the County, through its Building Dwiswn, under iulergowninratal ^greunnsiH with ihu City
("l(;A"J, fcas historira!ly enfrtrreri the LIX" prwisiuiss jpplicatiie lu the OUs within the City; and

WHEREAS, the iGA tor building services between the City anrt the County is rrn longer in effrrt; and
WHEREAS, the purpose of this Ordinance and the regulations adtoptai hereby is to establish
institutional conLruls iifflilir to those enacted by the County applicable within t-* Site nn thews portions of
OUs 3, 5, 6, 7, 8, and 9 lying within the City; to meet the requirements of the various EPA Records of
Decision or Action Memoranda that require institutional controls; to implement the requirements dpsigiifd
to prevent contaminated wih» from being handled improperly, and to assist the EPA in deleting the Site
fl'utn the NPL; and

WHEREAS, the City is authorized pursuant to Snellen 31-1.*5-401, C.R.S., tc exercise its police powers to
pry mote and protect the health, safety, and welfare ofthf community anil its inhabitant?, and

WHEREAS, the City Council has determined that fhi.s Ordinance furthers Lfi« public health, safety,
rorivfinien.ee and genera! writer* of the community,

NOW, THEREFORE, HK IT ORDAINfcl) BY THE ClTV COUNCIL OF THE CITY OF LEADVILLE,
COLORADO:

Section 1. Section 1 *>.34.020 of thi: LeadvEUc Municipal Code, concerning amendments to the Snternatlon.il
Building Code, is hereby amended by the addition of 4 new" subscctirm numbered 36, to read as follows in

its entirety:

36. IBC Section 1803, entitled "Excavation, Grading and fill" is iWiprnfM hv adding a new subsection
1803.? to be entitled "Compliance wnh Institutional Controls" which shall read as follows:

IBM,7 Compliance with Institutional Controls. Ksravatiom and grading within those (Rniioc'.s
of Opc«:fcmal Units 3, 5, 6, 7,8, and 9 of the California f.ulrh Jiupprfund .Sit* ("Situ") lying within
the City shall comply with the provisions of Chapter 15.36 of the City ot Leaclvilte Municipal Code.

CltyofLeatMlfe Onttoaar* 3, Ser.es of 2Q13. Culikntii Uaith SupwfunJ Silt InEttatumtl CVnuuit	Page laf 5

K-21

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Section 2. The Uaclville Municipal Code is hereby amended Ity the addition nf a tttw Chapter iVHfi,
pntirif rl 'Jnsrihirwnal Canlrnh fnr the f'.^itnrnia Gulch Superfind Site" which shall read as fallows in Its
entirety:

Chapter 15.36

INSTITUTIONAL CONTROLS FOR TUB CALIFORNIA (illl.CH KlIPEHHJND SITE

Sections:

1S.36.01U General provisions.

15.36.020 Definitions.

!53403ft Variances nrM allowable.

15.J6.040 Rt»t Matwp«irniiil Practices informational hamliKit.

15.36.05l) Institutional Controls far OU3, OU5, OU7 and OUB ar.rf penalty tor violation.

ISJfi.Oftfl Institutional Controls' fnr 1)11'J arsri penalty far violation.

15,36.010 General provisions,

A. these regulations are necessary to compiy with U.S. Environ mental Protection Agency
requirements far institutional controls for the various operable units of the California Gulrh Superfurid
Site located partially within the City

K. f.riartmerit of these regulations Is required by the U S- linviror»mpntal Protection Agenry In nrrter to
achieve deletion of the various operable units from the National Priorities List

C. The iinpfeiiiKiitatiori of rhi*se Institutional controls which regulate excavation stud bu«ldriij| aclivitws
within certain locations of the ("allforr.ia Gtikh Superfuiwf Sir* will ensure Hot various Site remedies
rnmarn protective of human health and the environment arid may a'so minimize the disturbanrp, transfer,
inhalation and ingestion of rontamlnatod soils., rtrtis potentially lessening any rLsl< posed by certain

portion r animation and/or protect the

integrity nf a remedy by limiting land .or resource use and/or by providing information that helps
rrimhfy «r gnlrie human behavior at a site.

"iVatZona! Priori!/es- List" nr "NPL' means the list of hazardous waste .site* eligible for long-term
remedial action financed under the federal Sup&rfunc! program. EPA may delete a final NT! site if it
detrrmlnps that no further response is required to protect human health or the environment. Partial
deletions may ako he conducted at Suporfund sites.

"Nm-Kngimered Wemetif means an SPA approved remedy comprised of a geographical area of an OU
that does ncn Include an engineered remedy. Non-engineered remedies may require pi oper
management of potentially contaminated materials In order to protect the integrity at the remedy and
to prevent human and environmental exposure. The non-sngineered remedies subject to irwtifurlnnal
controls tor certain OUs of the California, Gulch Superfuml site wit lx defined by a map contained in the

"it* .3' katlvi;k Ord nance i. Ser-cs of 701 J, tali fornji Oul J- Super fund Sue Wntutwrwl Controls	F«jr ?. m S

K-22

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Late County Build mji and Land Use Department,, Lake Courtly Clerk and Recorder's Office, the kike
County Assessor's Office, and the City Clerk's QfTkc.

"Operable Unit" or "OU* means a. designated gesgraphicatty based am with in the California Gulch
Supprfund Site

"Operabh: Unil T of "0U3' moans the Oil fully described lay the EPA Record of Decision tor Operable
Unit 3. dated May 6, 1¥)U. Generally, QU3 crtccrepasses several different slag piles and historic rail
yards, including the Harrison Avitjatie slag pik* and a portum of the Mineral ScilTrail
"Operable Unit 5" or "OU5~ means the OU hilly described by two FPA Remrds of Decision for Operable
Unit 5, daied September 29, 2000,, and October 31 200P. Generally, OUS errc«rtipa»cs the ASARCQ
Smeker/Coloracto Zinc Lea it Mill Silt- smelter sites around LeadvUie and one mill site, The smelter
sites include the FGWA site Smelter, Grant/Union Smeller, Western line. Smelter, anif Arkansas
VaIJbv -Sr«;rt ItilS.Tirlf .Slag Pile) and the* AV/C21, .sltas (Arkansas Valley Smelter and Culurad'o Zinc Li-ad
MiU].

"Owotfe |/rwi 6" or *0U6" mems the OU fully described by the EPA Rocyi d of Decision for Operable
Unit 6, dated September 25, 2003. Within the City, 006 consists of rite western portion of the Penrose
Mine Waste PH« that was rainsnliriaitni and capped in 199ti, and also the Stray Horse drainage
conveyance along 5m Street and the portion of Starr Dilcti bptween S!h Street and California Gulch.
"Operable (fall 7" or "OU?" means the O'J fully described by the EPA Record of Decision tor Operable
UniL 7, dated June 6, 2000. Generally. OU? consists of tie Apache Tailing impoundment that was
conwiidBled and rapped m 2002.

"(ipcrabtc Unit 8" or "COT* means the OU hilly desrrihefl by the KPA Rprnrd of Derisirm fur Optra hip
Un;t 8. dated September 200(1. Generally, Ot'O consists of the 500 year floodplain that is located
between the Yak Water Treatment Want and the po»nt where ti« gulrh enters the Arkansas River.
Wort on this operable unit was completed m 2002 including removal of tailing, nan-residential soils
and channel stabilization.

"Operable Unit 9" or "OU9" means this Oil fully described by the FPA Record of Decision for Operable
Unit 9, dated September % 1999 and the Kxplinat»c-n of Significant Differences dated Spptwnbm', 211IW.
General}/. 0119 ftjnstrts ol those porrlnns of the Site where the- land use is residential or that are-
currently owned as resid enttal/popuuited areas and as low-density residential areas,

15.36.031) Variances not allnwahl-e. Tltcxi; institutional control regulations shall not be subject ta
any authority to vary the building or 'iMiinu regulations of the City. No variances are permitted from this
Chapter of the Code.

IS.36.040 lest Management Practices informational handout Each applicant tor a City building
permit within the boundaries of 0U3, OU5. OU6, QU7,0U8. and the six mine waste piles within the City in
0U9 of the California Gulch Superfutsd Site will be provided with a handout from the City Building
Services Department or provider regarding Lake County Best Management Practices for managing
potentially contaminated soils in ilie City and Lake County. Each applicant shall be obligated to sign a
document attesting to the fact that he/she has received, read and understood the Lake County Best
Management Practices handuui. No building permit shall be issued without the applicant's written
acknowledgement provided to the City Building Service* Department i>r provider,

IS.36.0SO Institutional Controls for OU3, UUS, OU6, 0117, and 0118 and penalty for violation,
A Engineered remedies. It shall he unlawful to erect construct, reconstruct, alter or modify the
footprint of  certified mail. The Colorado
Department of Public Health and Environment will provide .in initial response within ts=n (1(1) d*yv i>f
receipt of thu written request and will use Vst rfforts tn coordinate with landowners tn provide a timely
resolution of the request. Applicants arc solely responsible for obtaining written approval f*om the
Colorado Department of Public Health and Environment.

€:ty r*f UjaHviIW* {Sr$n,
-------
11 Kon-pnginfered remedies. It shall be unlawful to excavate and remove any earthen rawterials
including, bu! not limited tn. native dirt, native soil, rnir.e waste rock or mine tailln^h, sldj within -.tn (10) day* nf npreipt cf the
wriitwi mp«st arid will use best efforts to coordinate with landowners to provide n timely resolution of
the request. Applicants are solely responsible tor obtaining written approval from the Colorado
Department fit Public Health and Eir.1ronr.tent.

C Viulatisws and penalty.

1.	It slill be unlawful to erect, construct, reconstruct, niter nr modify the footprlnf of any building,
structure or improvements on land, including excavation, within an engineered remedy ji 0113,
0U5, Oif6,01J7, or OUB of lhn California Gulrh Superfiind Site withnut prior notitication and written
approval frnm the f dorado department of Public Health and Environment

2.	It shall he unlawful to remove any eartb«ii materials mrliidimg, but not limited to, native dirt, nntive
soil, mine waste rock or mine tailings from the owned pawl of as EPA ntsn-Mglnperert remedy !n
excess «r tun (10] cubic yard"; in OlO, iJIIS, Oli6, 01!?, or OUB ot the California Gulcn Superhmd Site
without prior wrirten approval from the Colorado Department of Public Health .atad Environment.

3.	Failure ti> provide prtur notification ami written approval from the Colorado Department of Public
Health and Environment far these otherwise prohibited activities is a viratiwi of this Code and
iuljiett tu a penally of a Ens of up to One Thousand IWtars ((irKllKQO). Artdstiormlly, the infraction
snail br reporter! to the Cufuradu Department of Public Health and Knvtrannienl by a letter from the
City BuiklMj; Service* Department or provider.

15 36 060 Institutional Controls for Six Mine Waste Piles Located In 0U9 and penalty for
vUtlatton.

A. Six Mine Waste Piles Located within the City m 0119 of the California Gulch Superfund Sitr. IS PA
issued an Kx plan at I on of Significant Differences in September 2009 f'ESD") tu document sisnlfkaM
differences ta the Record of Dedsian {"ROD") for OLFJ. the September 200'J ESD documents CPA's
decision to require institutional controls for a total of seventeen mine waste piles within 009 that luve
soils at the surface under the 3S€§ parts per millirtn lead resedential ar;ior> tevei, but below the surface
may have lead contamination eice-eding the residential lead ddiuti l«v«k EPA designated the seventeen
mine waste piles as engineered remedips in , and (h# City Clerk's Office.

D, Engineered Remedies. It shall be unlawful to erect, construct, reconstruct, alter or modify the
footprint of any building, structure or i reprove mcaii un hud, including extavaLimi, within an engineered
remedy in 0U9 uf the California Gulch Superfund Sit* without prior notification and written approval
from the Colorado Department of Public Health and Enviramnttni. Written pruuf of approval frrsim ihn
Colorado Department nf Public Health arid Environment is a condition precedent to issuance of a building
permit liy the City Building Servicta Department i»r provider. The applicant shall submit ,i written
rvi|i.i«st for apprnva! to the Colorado Department of Public Health and Environment with a copy to the
City Building Services Department or provider, p,ich via certified mail. The Colorado department ct
Public Health and Knvironment wil. provide an initial response within ten [10) days nf receipt of the
wi itt«i request and will use best efforts to coordinate with landowners to provide a timely reso.ution of
the request. Applicants arc solely rejputislMe fur obtaining written approval fross the Colorado
Department nf Public Health and Environment
C. Violation a.-id penally.

I. It shall be unlawful to erect, amstrurt, reconstruct, altf»f gr modify the footprint of any building,
structure nr imprnvpiwnrs on land, including excavation, within an engineered remedy in OU9 of

City of Ltvtdvslb	\;t	X S«i u*:. ril 2Eil!i CaliK'fiiia O.iVii	Sitf	Cl*tl"£>K	J-'agc 4 ol $

K-24

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I he OijakH r.i.-t tiiikli sops-itwnd Nile wii liwit unisi 8V.ititii~.ili-.ui ,itkI wi men wpiu»al frrssii 0».'
Uili:t adu Dfp.iti ment nt pyhlii I lent* h ,«id fc'iviniurw r>i.

2. Fjliu'e lu provide |sriui iiiitit.raii'iii; .ind wi itli-n jppi x from tlie Gjiorjdc DupuiLiifiiit ul PuLIil
Hp,i)th rimj Erivimnipeiil fcr eIh'w uthet wiv,~ fHTih{'r ills* Cylwadn liup.iiuiienl uf I'mWil Health ,«id HnviPuitment hy 4 Irtter from r!".e
City Building Sprvicfs l>epnrtrnt*nT nr frovirlpr.

Section 3. Remaining hjovinhjcis Kt*.«=pf as nwiifiLjIlv d.iiKSik'd hereby, all ijlhor pi'uvisiuM t:f Lite-

lo.iisvtlle Municipal Code and the vajiMw	codes adopted by reference therein, ill,til cpminut in

full t'.n c« and e.Tnrt

Section 4. SfvmMMli. "ilumiil ,«iv ur>e nr nnn c ^cLtiinm ur piuvisuuis uf tins uuknaim' uujLtiid hr-iuby
be judicially detcrmiiK-ti invalid or u!ii!i:ftH'it«ibk, such pulRiuent shafi oat affctt, impair ur invalidate the
roiudininx ptiivtsiu;:.i of this, uriiinjhcp t!u> intrntiiJit bi/iiig that t:ic vanuus; .stintiuiis jjhJ pniviiiuris are

scvt'iablf

SetUrw 5. Repeal. Ar>y nnri O.II ortJInjno?? or rodM ur pnrts tfcerent in rnnflirt or iik-onsistfrit herewith

.iff, to tlw extent of such tonftxt «r intximisteniv, hereby rep?a)fil- provided, ifxiwever, thai the repeal oi
.my ".tiffs nrrtmamv r>r rod* or p.irt thereof sh.ill nnf revive any utlier .wtioo or part ot cmy prrhmtTW or
cud!.* yrovtsk/ti hwrtuforc rupfaleti at iupefbeded and this repeal shall nut .stf'ect or prevent the
prcvserutimi or pimrshrwnt nf any person for nny ;ii t dune or i:urnimttod ill vjol.itiwi «:i any n--;linan»'e ur
cr-de hereby repealed prmr to the raking effect of the; ordinanre.

WTHOUIJCKl), HEAD, AFPKIIWIJ AND DRDKHI I) I'UBl.lSHtU in full <>iv first reading llilh 2llJ da? of

April, 2013,

P'lihlisiit'sd in fttl in Tiff Herald Pmhxrwt, s newspaper of grrier.il nn ul.itinn in	f,olrtr,iriu,

mi thp I lth_«J and ariupteit nn final reatfirvg and ot'derert p«hlish«»i1 by tilli- i;n1y with anvrjdriifrrt?;
tirt thp ?1h day fit" Mrsy. 2tH,i

rtibhslU'il by title tink' with ,ir>y j,:t«>n.1mt-nts in '1"Jw lift aid flt-rriiKTuf, j iirwspjpe'r 1 •< uimicj-jI L'irn,l« «»ri#13. Cslift*i»i» (Mdi Sufwfiiml Site IiMiimie*pl fijiMKits

Page S of 5

K-25

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K-26

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Figure K-7: 2012 Environmental Covenant for Resurrection Mining Company's Zone A properties

1242260-R8SDMS

STATE OF COLORADO

EnculM	umi CHel MMCH Ottew

CMtauwl lo poading *nd fenpnmlng »a ntaHh ml •mwaammt o? ih* pia»>« at Ccttrado

*»0 C*»#rTy Crw* & 3	I USamWfy S«ii» DMsiOrt

D®n*»r, COKXMD B0i#6-1530	»l©0 Iwwy BIW.

F»oo» (X3) BSffl-MM	Osrtw, GoMratto SBZ3M6H	CblaadDDmRMM

l«M m> Giwidiia, CotQiado	
-------
IN1 III Hi IIII

SS92SS ®J1.*®12!0:54A¥ i*nc„

lorn cm mmmomoo u*c«n»wj»

IgCTonmmtaLCwenant for Zone A Property

This property is subject to an Environmental Covenant held by the
Colorado Department of Public Health and Environment pursuant
to section 25-15-321, C.RJS.

ENVIRONMENTAL COVENANT

Resurrection Mining Company ("Resurrection"'} grants an Environmental Covenant
{"Covenant") this £~™ day of fy?f.lt~	, 2UI1 to the Hazardous Materials and

Waste Management Divmtja of the Colorado Department of Public Health and tic Environment
{"the Department") pursuant f« § 25'15-321 of Ute Colorado Hazardous Waste Act, § 25 15-101,
& ,«/. The Department's address, is 4100 Cherry Creek Drive South, Denver, Colorado BU246-

1S30.

WHLKFAS, Resurrection is the owner of certain property situated in Lake County,
Colorado, more particularly described in Attachment 1, attached hereto and m«»rpi.»rated herein
by reference as though fully set, forth (hereinafter referred to as "the Property"); and

WHbRt AS, pursuant to that Consent Drew among Resurrection, Newiwnt IS A
Limited ("Newirurnt"), the State of Colorado and the United States, which was entered by the
U,S, District Cotut for (he District of Colorado on August 29, 2008 in Stare <>/ Colorado v.
,4son» Mmrpamred, cr at. ("Consent Decree"'), Resurrection has agreed to grant am
Envituntnenlal Covenant in accordance with the terras thereof

NOW, THEREFORE. Resurrection hereby granis this Hnviiwunratal Covenant tu the
Department, with EPA as n third party beneficiary, and declares that the Property as described in
Attachment I shall hereinafter be bound by, hcid, sold, and conveyed subject lo the nequucraetvit
set furili below, which shall run with the Property in perpetuity and he binding on Resume-lion,
its. heir>. successors and assigns, and any persons using the land, as described herein. As used in
this Fnvironcncntal Covenant, the term "Owner" means the record owner of the Pr\»perty and any
uther person or entity otherwise legally authorized to make decisions regarding the transfer of the
Property «r placemen! of encumbrancer t« the Property, other than by the exercise of eminent
domain,

1) C:* Restrictions.

a. No Residential U*e. Day Care Centers or Schools, as defined in Section 10, shall
be allowed on the property. No portions of Parks or Open Space (as. defined in
Section 10 below) that are designed or intended to provide a designated play or
recreation area for children shall be allowed. Prohibited play or recreation areas

1

K-28

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ill'' 11

.... llVkil	

359265 w Mm z: if 14 -vy rv.tr*®
2«3S COV SfcJS5AT*'"W	l.rfteC.W Rcmte

include designated picnic areas, playgrounds, ball fields. sand boxes and1 similar
areas, but illo roil include trail systems or walkways,

b. No use of untreated groundwater from wells located on the property for drinking,
domestic, or agricullural purposes shall be allowed. This covenant does not
restrict the use of groundwater that is treated to meet then applicable State water
quality standards for the beneficial use to which the water is being applied-
Treatment must meet any applicable State standards that arc in place at the lime of
use.

2)	Inspections,

The Department and EPA as the named third parly beneficiary shall have Ihe right of entry Us the

Property at reasonable times with prior notice for the purpose of determining compliance with
the tarns of this Covenant. Nothing in this Covenant shal 1 impair any other authority the
Department may otherwise have to enter ami inspea the Property.

3)	Termination.

This Covenant runs with the land and is perpetual, unless terminated or modified pursy ant to this
Section or Section 4. Owner may request that the Department approve a termination Br
modification of this Covenant, Consistent with C.R.S. 25-15-319( l){h), the Department shall
terminate this Environment] Covenant in whole or in part when, in addition to satisfying the
requirements of C.R.S. 25-! 5-321 (3) and (5), Owner provides the following applicable showings
to the Department:

a.	Restrictions on Residential Use arid other uses specific*! in Section 1 .a. shall be
terminated on all or part of ihe pruperty if Owner demonstrates to the Department
that the concentration of lead in the upper ft inches of soils on the property for
which termination is sought docs tttrt exceed 3500 parts per million (ppm), and the
concentration of arsenic in the upper 6 inches of soils on the property for which
termination is sought docs not exceed 340 ppro. Suc-h demonstration can be male
bawd on sampling analysis or evidence that the subject property is not Impacted
by any releases or threatened release of hazardous substances, Any soil
sampling conducted for purposes of terminating this Environmental Covenant
shall be conducted in accordance with Attachment 2.

b.	Restrictions on using untreated groundwater from wells located on ail or pari of
the property fur drinking, domestic, and agricultural purposes shall be terminated
i f Owner damonstritcs. to the Department that concentrations of the constituents
listed in Table 1 of Attachment 3 in the subject groundwater dn not exceed State
water quality starttlaniss for drinking, domestic, and agricultural purposes existing
at the time of application. Current water quality standards arc «t forth in T*blc 1
of Attachment 3. Any ground water Kanipling conducted for purposes of
terminating this Environmental Covenant shall be conducted in aeeordwice with
Attaefimcnl 3.

2

K-29

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ifllllHIEi

359265	Ji!: Mi 54 AM	Msrjer

3 of,IS t. >,.A 3S23?Stt WOO	Ln'« Couaiv Red

c. In addition U) the grounds for termination set forth in Sections 3.a and 3.b, the

Environmental Covenants shall also be terminated as to alJ or part of the Property
if it is demonstrated to the Department thai the proposed termination will ensure
protection of human health atuJ die environment, in accordance with C.R.S- 25-
15-319(t J(h).

Consistent with C.R.S. 25-15-321 (6), the Department shall pnnvide Hi Owner a w-ritt«jn
determination on all applications to terminate an Environmental Covenant vrifhin 60 days aftcr
receipt of Such application.

4) Modifications.

Consistent with C.R.S. 25-15-319115(1'}. A® Department shall modify this Environmental
Covenant in whole or in part when, in addition to satisfying the requirements of C.R.S, 25-15-
321 (31 arid (51, Owner provides* the following applicable showings to the Department;

a. Restriction* cm Residential l.'sc and other uses specified in Section 1.3 shall be
modified on all or part of the property i f Owner demtm^tratcs tu the Department
that portions of the subject property, where either soil lead levels exceed 3500
ppm or soil arsenic levels exceed 340 ppm. will be covered by a minimum of two
inches of asphalt, pavement or concrete, or other structures that prevent human
exposure to the soil.

1), Restrictions on using untreated groundwater from wells located on all or part of
the property for drinking, domestic, or agricultural uses shall be modified to
eliminate the restriction against one or more of these uses, if Owner demonstrates
to the Department that concentrations of the constituents listed in TuMe I of
Attachment .1 in the subject groundwater do not cxcocd State water quality
KtamlattjK in existence at I he time of the application for the beneficial use that
would be allowed under the iwdifiratkw. Current water quality standards are set
forth in Table 1 of Attachment 3. Any ground water sampling conducted for
purposes of modifying this Hnvironmetual Covenant shall be conducted in
accordance with Attachment 3.

c. In addition to the grounds for modification set ibrlh in Sections 4 a and 4.b, the

Environmental Covenants shall also be modi lied as to all or part of the Property if
it is demonstrated k> the Department that the pr»p
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359265 nvramojWAM J1#rtr.i3tK»
4^3® r»V it»3»» OlOiW	l^VantySnmfcfr

5)	Conv cyroccs.. Within thirty days (30) after any grant, transfer w conveyance of any interest
iri any or all of the Property, the transferring Owner shall notify the Department amd EPA as the
named third party beneficiary of such grant, transferor conveyance.

6)	Ntfticc to Lasers Owner agrees to incorporate either in full or by reference the
restrictions ofthii Covenant in any leases, licenses, or other instruments granting a right to use
die Properly.

7)	Notification, for proposed construction ati of this Covenant pursuant to §25-15-322. C'.R.S , and may file suit in district
court to enjoin actual or threatened violations of this Covenant.

' 0) Notices. Any document or communication required under tliis Covenant shall be sent or
directed to

NeiifiSSJ?fe OffffitpcnliaUJcjrojvidrfto:

[appropriate Program Manager or imi leader]

Hazardous Materials and Waste Management Division
Colorado Department o<;Public Health mid die Environment
4300 Cherry Creek Drive South
Denver, Colorado 80246-1530

Notices to EPA shall be provided to:

P.PA Remain] Project Manager
California Gulch Supcrfund Site

United State fcnvircmmcnml Protection Agency. Region 8

(SEPR-SR)

1595 Wynkoop Street

Denver, CO 80202-1129

4

K-31

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il'tllllill

35V265 ?.-.
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359265 W.ODC2 1(15-AM *•»*«»» B«®sr
ti.rf.w CV»V SS2J95R	;,ak« t wflyXcconW

A)	Household Living is characterized by the residential occupancy of a
dwelling unit by a household. Tenancy is arranged on a rnonth-to-month

or longer basis.

B)	Examples. Uses include living in houses, duple***, triple***, fourplexes

and other multiclwdling structures, retirement center apartments,
manufactured housing and other structures with sclf-enmluincd dwelling
anils,

C)	Exceptions. l«dgi«g in a dwelling unit or where less than two thirds of
the units are rented on a monthly or longer basis is considered a hotel or
motel use mid not residential,

2) On »up Living,

A)	Group Living is characterized by the residential occupancy of a structure
by a group of people who do not meet the definition of Household Living.
Tenancy is arranged mi a monthly or longer basis, and the si?c of the group
may be larger than a i'umily.

B)	Examples. The Croup Living category includes assisted living facilities,
treatment facilities, nursing homes and other institutions and arrangements
providing care or boarding for a group of unrelated individuals,

C)	Exceptions.

IJ Lodging where tenancy is generally arranged for periods of
less than 30 days is not considered to be residential.

I) Facilities tor people who arc under judicial detainment ami under
the supervision of swom officers arc not considered residential.

"Schools" means public and private schools at the primary', elementary, middle, junior high, or
high school level that provide slate mandated basic education, including associated play areas,
recreational mid sport facilities, and before- aid alkr-sdioo! cure facilities, The term shall
include daytime schools, boarding schools and military academics. The term shall not include
business or trade .schools.

12) Property Modification. Pursuant to the Consent Decree, this Environmental Covenant
is intended to cover only that portion of the Property on which the Settling Defendants own the
entire fee title. If Rourreclion and the Department hereafter agree that, as of the date of this
Environmental Covenant, the Settling Defendants did not own the entire fee title in any portion
of the Property, the Department will modify Attachment I hereto to exclude that portion of the
Property from coverage under this Environmental Covenant.

6

K-33

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3593565 7/3 WO 12 10:54 AM
7 of 38 COVRSJ39.50Dt0.00

Hrrgff

Lift* C«K% Recorder

ResufprLlkwi has cau*c«i this instrument to be executed this ^day of

- tipwf 	__.20l t.

Resttrrertiem Mining Company

ST ATP OF	Aje^Jd 	 )'

71 /	> ss

COUNTY OF. Litest A*-*	>

THe foregoing irw»T>nicut wax acknowledged before nif this^^'tjav ol /.,
20H	P	Mi a I f«> f R e.ni rr ei;t ion Mining; Company

J 4-Uik_.. Jz* h*\Ui

Notary Public

My commission expires

j; t. Sail

1*36$. _	Jnj£* s<^Ma Sk

Address

I-

,jHLt»%3ltr p k1fSu

r<

by the Colovtuki Departnunl of Public Health and EnvnTmment this &?Tkv of

MwtL.			 i

SO- rrg. it* fJjZi /UJ<

\$*y*

P



Title:

f/A*m

7

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COV RS2W.S0 moo	'« R i-corilfl-

STATH OF C/X^'2At>n
cotj.viv of "DFjU-Jfr-ZL.

) »;

The forcgoiag instrument wxi -ackno wiedgod before me thigf^^day of Jo pi 	

.-^bi^bv QAf?.y/ /i.) A1' of the Colorado Department »j' Public Mcallh and
Environment.

Notary Pubfat

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AIlACIiMKVr 1

TO KNVIHOVMKMTAl. COVKNAN1
THE PROPKR'I V

C laim Name

homier

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Bulls Hye
tteme
H P. lrjKl Suh "A"

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T S Wells & Wm. Mover Placer (net C
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Nevada

tlDCV

S)np»*tnr«D
('onr>tock So 1

Crarthntr
Maud Hicks
1 .iHle Fftrepomglt
IntfcpcfxJtTti
f-cliji

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Fv«elf
Little Hcrtlia
Tankets»wn
Tribune
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Tiun
les* Oak
William Roddick
linpita
Mar.a
Ballard
Eiiietpim-
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Litllf Varate
Badger Stale

Buclttji
Irene
Silver Wave
Aa-htr
Florence
Wataw
Glcnsury
Doncvatt
McPeriemh Phicer Tract 0
McDcrmilh Trad A
Mc Denrrith Incl D
McOtmnlh trail E

f

K-36

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359265 111 ©Oil 10:54 am P«Mi&oispr

W of II COV 1121ft JO DStUSO	lite County Ractyder

Claim >ame

Mineral Survey Nil tuber

?i;hcH

i	•	Hirtford I reel S»ub H

802	Vmen

813	Mahinoy

f*49	Uazw

XA2	Unknown C'luun N«iw

883	Triumph

ft9>	Whiw Cap

W	Farfcit

OT5	Honcv Omb

9(|9	Arrows IhrOcnn

Wft	Hsittlew

1(WVS	Detlit

lOPfi .	Eagle

lOlfl	hbpCTimmg

I n.->8	Ruby

1(130	Silver Nuggvl

IfifiS	A P WiiEord

|(«1	fllniJ* Place?

i !20	Royal

1125	Ailelphm

11(it	Or** Wi*

i as j	r itv

I "271	Si, lefesa

1119	Red Heat)

1.123	Rl Jo-»cph

135'H	Minnie Lee

1159	Mineral Fsnps

1444 , '	fUvcmw

MSI	Mabel

|4>5	Huinholrft (ProducinR CUht.)

1481	SiMjl Spring

MM	Amlefcpe

1488	H iogl.uk

1491	Yellow Jacket

1501	i ink Nellie

1532	T.ittl«DaUy

1542	Unknown Claim Name

1543	Hog bye
1552	Slaroftfte Wesf
1514	S«4Uin
1588	V in in j
{59?	Pinal Furac

1594	Ottawa (Produceog Claim I

1654	Elk

1772	Rattling Jack

189 J	Oriole

1S0T	Deer

1912	Carlton

1918	Bessie Wilgus

1928	Snadacr

1935	Revenue Culler

233*	Cnlonel belters

10

K-37

-------
Illlllllilli

359265 73WM21M4AM Much

iltfJB eov i$23f J§ OSO.OO	MKCMwy Smite

Claim Name

Mtnrral Survey Number

2*vU	SIX

Mianoot*

2678	UNKs-

2^88	ntva Lima(Prtwtixmg Claim}

271 *>	Ksy*nw

271"?	RrM

27VS	Ffuddw

2 NO	Miwm*

288?	4 Li

2«20	Old Rye

HW2	I M

3111	feint 1,.

I	Daniel O'Csqmell

.1154 ,	SeJvlin

J155	Bfih IngerMil

1156	N. Rollaii

3161	M'Jhr.

3162	•	Ontario-
J)6«s	Praline
3KSS	Satellite
3169	Uk A A.K-C
3217	I-illic
343?	FAth Tangent
348?	Leo
363 U	fed Pmphyrj
iS22	" Bulldcwr"
Vt77	Old Maid
4161	Unknovm Claim Name
4167	Unknown Omni Nome
424<	(ienent OfAnt
*7^	li'tank

4JM	Laurel W

««	K * (

¦iw	n»bv

4542	Mottjuilu

4624	My Pay

4626	Hernies

4M3	Trumble

5596	H idden T rrasuw;

5 Ml	TpjiuyJlt

6269	Unkwiwn Clnnti Name

$9 J 3	Mk&rk)
I.W» Margaret (Producing Claim)

15) 4	Unknown Claim N-ubc

S«1	Setups

*T2~	SJiwkton

(1982	Grovef Clcvd«K)

8990	Terrible No, .

KWO	Terrible Nil. ?

8990	Tcmbl« No. *

sKW	I.mcob A Joiner

926 i	Unknown Claim N-imt

M52Z	Whip

It

K-38

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359265 tmmnWMm VMricut fimpr

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Claim Name

Mipertl Surv«y Number

 .. 			Mr*

sMJN	Smuialet

jUOS?	Link May

ill8?	Onondaga
; 2343 tnicrmural (Produrinfi Claim)

1344S	(1 T.M

13?®]	Ralph
16064 tircal ex New Y art A (Producing CUud)

17'TJ	Unlax-wn Ci*im Nunc

18112	P.X.O

18184	Lcm 1 cam

1843?	L" nkno wn C laim Nunc

18 7 * fl	Unknown Claim Name

19611	Wcm Ff*c«pn

J 9634	Frank) 
-------
IlilllllHI

159265 *31/3012 W $4 AM W?t«*B«fgsr

llrfis GOV t$».» imm	Ukt County Reenter

ATTACHMENT 2

TO ENVIRONMENTAL COVENANT
SOIL SAMPLING FROCfclWRKS

Soil Sampling and Analysis Plan

This attachment specifies the soil sampling procedures for purposes of terminating an
Environmental Covenant restricting Residential Uses or other uses specified in paragraphs A.2.a
or A3 a of Appendix F1 . Those restricted uses are collectively referred to herein as "Uses." For
purposes of this protocol, a "property" is defined as a portion of a claim, an individual claim or
contiguous claims On which an Environmental Covenant restricting Uses is proposed to be
terminated. A portion of 1he subject properly proposed for Uses may also be subdivided for
purposes of terminating or modifying an En\ irownecital Covenant for only the subdivided
portion of the property. The following sections describe the soil sampling retirements,
methods, sample analysis, and quality wurant* lo support termination of the Environmental
Covenant. Alternate soil sampling protocols and analysis methods may be proposed in a site-
specific sampling plan for the property, subject to approval by the State.

1.1 Soil Sampling Requirements and Protocols

Soil samples will be collected to a total depth of six inches, except in areas that are covered or
will be covered with a minimum 2-inch (Kick layer of asphalt or concrete or other structures that
prevent human exposure to soil or will be covered within a minimum thickness of si* inch® of
imported clean soil. Soil samples will be collected at Wo depth intervals: one from 0-2 inches
deep and one from 2-6 inches deep. Each of these wo soil samples will consist of a composite
collected from three sabsainpks from the same depth interval, as described in Section 1-2 below.

Composite samples for each depth interval (0-2 inches and 2-6 inches) will be collected at four
locations per acre, with not less than four composite samples collected for each depth interval a
property. The composite samples will be equally spaced within the property. Hath composite
sample will consist nf three subsamples of approximately equal amounts of soil collected from
the same depth interval, At each composite sample location, the subsamples will be col looted in
a triangular pattern with the snbsaraplcs ipaced approximately five feet apart. The composite
sample will cons!si of (he three subsamples collected from the same depth interval,

If any deposits of mining, milling, or smelting related materials (waste rock, tailing, or slag) arc
known or suspects! to be present wifhin the property, the footprinl of these areas will be defined
as separate sampling areas not to exceed 10,000 square feet each (100 feet by 100 feet) A
composite sample (minimum of three subsamples) will collected fixmi the materials within each
sampling area to a single sampling depth of §-6 inches, or less, if the materials are shallower.

Imported soil shall be sampled as defined below to demonstrate that the imported soil has lead
and arsenic concentrations less than 1,5fl0 tng/Kg and 340 mg/K.g, respectively, for Residential

Hie,

IS

K-40

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i in ii m if ii

359265	10'. 54 AM Wn«ii Berger

'4of«l rev 1S235 30 IKMM	Lata! Cdmitiy Recorder

Prior to soil sampling, a site sampling plan will be developed and the sampling areas and
sampling locations will be plotted on a site plaa, The site sampling plan will show the property
boundaries and any existing residential structures, commercial facilities, or improvements. The
sampling area* and sampling locations will be Mollified an the site sampling plan. In addition,
any known or suspected deposits of mine, mill or smelter related materials (tailing, waste rock,
or stag) will also be delineated an the silt sampling plwi with sampling locations identified.

1.2	Soil Sample Collection and Handling Procedure.

Soil samples will be collected using a plastic or stainless steel trowel, soil probe, land auger,
spade or drive sampler. A pick or spade may Ik utilized, as necessary, to looser the soil for
sample collection, The specific sampling tool utilized will be dependent on the soil composition
and density. Additional sampling equipment may include jtainlesi steel bowls, measuring tape,
hand-held GPS, plastic sample bags, camera, log book, pen, pencil, and marker.

At eauh composite sample fowtkm, & subsompte will be collected at each apex of a triangle
spaced approximately five feet apart. At each subsaniple location, any loose debris at id any sod
or dense vegetation will he removed tk>m an area approximately six inchev in diameter. Sampler
will not be collected under or immediately adjacent to trees, shmbs and or stmctures. A soil
sample will be collected ai the same s>ubsample location lo a depth of 0-2 inches and then 2-6
niche*, using the sampling tool, Approximately the same volume of soil should be collected at
eflch subsamplc location for each depth. The soil from each subsample will be collected into a
separate clean plastic bag or stainless steel bowl for each sample Uepih interval. 1'or each
composite sample, combine the subsaniplcs from the same depth interval together in a sealed
plastic bag and mix by hand in the sealed bag. Label ihe plastic bag with the property
identification, sampling area, depth interval, and date of collection. A chain of custody form will
be maintained for all soil samples from the time of collection until its final deposition.

All equipment used for soil sampling will be dedicated or will be decontaminated prior to sample
collection. Decontamination equipment will include, pump spravera, spray bottles, deionixal

water, phosphate free soap solution, scmb bmshes, buckets, disposable gloves, etc. Field
personnel will wear disposable poly ethylene gloves to avoid sample cross, contamination during
the collection uf »kh1 samples.

1.3	Imported Soil

Soil imported to a property for use within the upper six inches of the final ground surface will be
sampled to demonstrate that the lead and arsenic concentrations achieve acceptable
concentrations for residential use and that the lead concentrations achieve acceptable
concentration* for commerviiil use, as detined in Appendix. Fl. Far up lo 1,000 cubic yants of
imported soil delivered to a property, a sample will be collected every 250 cubic yards, For
volume* greater than 1,000. cubic yards, a wimple of tile imported soil will be collected for every
SOU cubic yards.

1.4	Equipment Decontamination

Sampling equipment will be decontaminated between sample collection points, if the equipment
is not disposable, in order to avoid cross contamination between samples, field personnel will

K-41

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159215	2 10:54 AM FWrio» B«pf

1S,if.W COV 1123# 50 tmo© • Lake Oowly Recorder

wear disposable gloves while decontaminating equipment. The following procedures will be
followed to ensure thai sampling equipment is dccontammated:

1 j Visually inspect sampling equipment for soil; a stiff bmsh will be used to remove
any visible materia]

2)	Wash the field equipment with phosphate free soap and water, rinse with distilled
water, and air dry or wipe with disposable paper towels

3)	Water used for decontamination will be disposed of on site. All disposable items
such as, paper tuwds. disposable gloves and wash cloths, will be dtiposiled into a
garbage bag arid disposed of in a solid waste landfill

1 5 Sml Sample Documentation

Field sampling information will he recorded in a field logbook or field sampling forms
Information that will be recorded at each composite soil sampling ligation will include the

location fe.g. determined by hand»helil OPS or measured in i defined reference point) unci
sampling depth interval. The documents, to be completed for each composite sample in each
sampling area, arc:

Site Plan fPlot Plan)

Chiii)-i>(-Custody transmittal form
Sample tag and'or label
Sample master log

All pertinent sampling information will be recorded on a field logbook, Entries will be made in
the field documents in indelible ink, with all corrections consisting of initialed line-out deletions.

Each day s entries will be initialed ami dated at the end of each day by the field sampling crew

At minimum, entries ir« the field log shall include;

Date and time

Site description tie,, physical address and assessor pared number)

Description of weather conditions
Names ut:field sampling crew

Description of wtc conditions and any unusual circumstances
Location of Rumple site, including map reference
Equipment identification

Details of actual work effort, particularly any deviations from :hc afcrcmcclionedi
method*

Field observation*

Details of photo documentation, if any

IS

K-42

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359265 731/201210:54 AM	Patricia Bag a

16,>.fW cnV RSSJS.SO 1*00	fjtoCwmylUtMdw

1.6 Soil Sample Packaging arid Shipping

Each sample awiteincr will He properly labeled in the field, All containers will be checked for
proper seal and entered by sample number on the chain of. custody form. After collection,
nunpoiite samples will be placed in an insulated cooler fnr storage in the ticltl.. Samples will be
shipped to Ac laboratory in a cooler with ice. I be ice in the cooler will be double-bagged. One
copy of the chair, of cusUxlv form will be enclosed in a plastic hag in each cooler containing the
samples identified on the form- The cooler will be taped shut and custody seals will be attached
to the outside of the cooler to ensure that the cooler cannot be opened without breaking the seal.
The cooler will be shipped using an authorised shipping service to the laboratory for analysis,

I.? Soil Sampling Quality Control

Duplicate samples will be collected ami submiticd to (he laboratory If evaluate (he precision ami

reproducibility nf sampling and analysis procedures. Duplicate samples will be collected at a
minimum of one for every 10 soil composite triples The duplicate samples will be collected,

preserved, packaged, and hitmiltsd in the same maimer as the snii samples. No cquiprr.cnf blanks
<>r field blanks will be collected.

1.1 Laboratory Analytical Protocols

The soil samples will be analyzed by the laboratory using methods detailed in Test Methods for
Evaluating Solid Waste. Revised Methods, SW-K46. The laboratory shall be accredited by the
Colorado Certification Program. For Residential Development, samples will be analyzed for
arsenic and lend. For Commercial Development, soil samples will Ik analyzed for lead. Soil
samples will be digested in accordance with SW-846 EPA Mulhod 3050. After digestion, all
samples will be analyzed by EPA Method 601 OR.

The report of analytical results will include a cover letter from the laboratory identifying the
sample group and any noo complaint quality control results together with the affected samples.
Attached to the cover letter will be a summary of sample results and a summary of quality
control results. "The summary of quality control results will include instrument performance

results such as standard recoveries and Wanks results; matrix QC results such as .spikes,
duplicates and procedural blanks, and laboratory control standard recoveries.

16

K-43

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lilllllillH

35926? 7M|.:«I2 III <4 AM	(iflTK.afiejttf

COV REW.jn nvcin	I #1m exility Recede.

A JTACUMLNT 3
to I.NVI HON MKNTA!. COV>N\NI

GKO I. NI >\\ ATE R SAM PI 1NG P M< >K KlO l.S

Groundwater Sampling *tid Analysis Wan

This attachment specifies the groundwater sampling procedure* for purposes of term mating or
modifying an fcnvjronmcntal Covenant for groundwater use restriutiwis, as specified in
Appendix I I. l;or purposes olUhe protocol. a "properly" is defined as a portion of a claim, an
individual claim or contiguous claims not exceeding 35 acres in total area for which the
groundwater use restrictions of.an aquifer are to be terminated, The followings sections describe
the groundwater swSripling requirements, methods, sample aitalysis, and quality assurance that
will support such termination or modification, Alternate groundwater sampling procedures and
analysts methods for a property may he proposed in a silc-spccific sampling plan for the
property, suhjcct lit approval by the Slate.

1.9 Groundwater Sampling Requirements

One groundwater sample will be collected from a well completed in the aquifer of the
hydit) gee logic until (alluvial, unconsolidated sedimentary deposits, or bedrock) pretpnscd for
beneficial use underlying each property, for alluvial or unconsolidated sedimentary deposits, the
hydrogcologic unit is defined as the aquifer with the same Ethology ami within the same surface
water hytJrolegic divide, 'lie bedrock hydrogcologic unit is defined as the aquifer within the
some geologic formation and structure. The groundwater use restrictions will be terminated or
modified for a property lot only that aquifer of the hydrologic unit in which the well is
completed.

The groundwater sample fnini die well will he analyzed for constituents that are relevant to the
California Gulch Superfund Site for which numeric groundwater quality stundartfa. have bear
established by ihc Stale for the proposed beneficial use al the lime ofi the application for
termination or rwtdifitatiori ofdhtr F.nvm>nmerjf;d Covenant.,hereafter referred to as the Numeric
Standards, The constituents that arc relevant to the California Gulch Superfund Site and the
current Numeric Standards are presented in Table 1 for drinking/domestic or agricultural uses.
The groundwater in tic aquifer will be determined acceptable for the proposed use, and the
Environmental Covenant restricting groundwater will be terminated for the property or modified
to allow a particular beneficial use, it! the constituent concentrations ofithe sample from the well
arc less than lie Numeric Standards for ill beneficial uses (in tie event of termination) or the
particular beneficial use (in the event ofimodi fie^tion).

UO Ground water Sampling Methods

The groundwater sample from the well will be collected according to the methods described in
SOP No. 4-Ground Water Well Sampling, N on-dedicated or twn-disptwable sampling
equipment will be decontaminated prior to collection of the sample according to the methods
described in SOP No, 1-Decontamination. Sample collection documentation, sample

1?

K-44

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159265 7-31-Xi;:'i:-54A.\f	Pr.rfcta Rrtgc

IK,-: \si ::r>V RSi"® 5^i»ivS

lJia*'L

0.2 tntfL

RuoriJc-iisielvrf

4 J mg/i

2 mu'L.

fton-ditaolved

0 3 m&'L

5 mg'L

Ixvriklissolved

0.05 in grl.

0.1 mg'L

MainaBBe-iisselvHl

11.05 m&'L

0.2 m&'L

Menaary-^Ussdved

ojx&

0.01 mj^'L

MolybdeflumHdiasolved

0.035 rnjt'L



Nickel-dissolved

0.1 nm/L

1 " rii "

Selenium-dissolved

0.05 m«/'L



li»er-iiiasQlv«l

0.06 m&'L



Sul fatc-di .isol v«d

2 SO m*'L



llalliuia-iii»lwrf

0.002 mg/L



Zlnc-iiisolvrf

5

1 mm' L

II

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359215 ?/!ia«210 54 AM [-atnew >r*rr
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SOP-1

SOP Dafe,' I tbtuary 2008

DECONTAMINATION

l.f» lMRODDCTIDN AND TYPES OF CON'TAMINA 1 ION

The purpose of this document is to define the standard procedure lot decontamination associated
with tmvitunmenUt investigation ft* Hit* California Gulch Suptrfuml Site. This procedure i:-.

intended to he ysetl with other SOP*.

LI Site and/or Sample Crnss^Contaminalioji

11* overalJ objective of multimedia .sampling programs is to obtain samples which accurately

depict the ebcroicaL physical, andor biological conditions at the sampling site, Extraneous
contaminant materials can be brought onto the sampling location-and/or introduced intn the
medium of interest during the sampling program (e.g., hy contacting water with equipment
previously containinatcd at another sampling site). Trace quantities of these contaminant
materials can thus be captured in a sample and Iwsd to false pMsilivt: analytical result* ami,
ultimately, u» an incorrect a.s%ont«mi riant conditions assMScytol with the site.
DtxontaminatKm of Jiotv dcdicirtcd or m>n-disposable sampling equipment (e.g., baiterc, pumps,
and tuhing) and field support equipment (e.g., drill rigs, vehicles;) is required. To ensure that
sampling cross-con t«n in «tion is prevented, ami that on site contaminants are not earned off site,

2.0	PROCEDURES

2.1	Equipment List

The following is a list of equipment thai may be needed to perform drnvrtamiftatrntr

B rushes

Wash tubs

Buckets

Scrapers

Stcasn cleaner or high-pressure washer
Paper towels

Aicooox detergent (or equivalent)

Potable water

Deionized or distilled water
Garden type water sprayers
Clean plastic sheeting and/or trash ha^s

22 Dccoala ruination



K-47

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2.2.1	Sampling Equipment

The following steps will be used to decontaminate iwm-dedicjttcd or non-disposable sampling
equipment (including reusable filter apparatus):

Personnel will dress in suitable SHit'eiy equipment to reduce personal exposure (e.g.. laic*

gloves, safety glasses, etc, |,
dross contamination an equipment will be scraped offal the sampling Or otmsimetion site.
Equipment that will nol hedwriaged by water will be washed with sin Alconox solution or
low-sudsing detergent ami potable water and scrubbed with u bristic bmsh or similar
utensil (impossible), Equipment will be triple rinsed with potable water followed by a
triple rinse with deionized or distilled water.

Following decontamination. equipment will be placed in a clean area, an or in clem plastic
sheeting to prevent contact with contaminated soil. If the equipment is not used immediately, the
equipment will be covered or wrapped in plastic sheeting or heavy duty trash bag?. to Minimize
potential airborne contamination.

2.2.2	Submersible Pumps

If non-dedicated submersible pumps are used they wit! be decontaminated between wells,. The
outside of the pump and hose will be tripled rinsed with deiontzed or distilled water, Dcionim!
or distilled water will be pumped through the pump and hose. The volume of deiemized or
distilled water pumped through will be at a minimum equal to three limes the volume of Haiti
thai could be contained by the pump and hose.

2,2J> Water l.cvcl Probes

Efeclric water level probes will be decontaminated by rinsing with dcionizcd or distilled water or
by wiping the probe during removal with paper towels welted with deiimi/ed or distiilud wdtcr.
The water level probe will be placed in a plastic bag alter decontamination.

2.2.4	Sensitive Equipment

Sensitive equipment that may be damaged by water will be carefully wiped clean using paper
towels and detergent water or spray bottle and lowcl and rinsed with deionbed or distilled water
Care will be taken to prevent any equipment damage,

2.2.5	Drilling arid Heavy Equipment

Drilling and heavy equipment will be decontaminated at a designated tlecontairiination area for
larjic equipment, The following steps will be used to decontaminate drilling and heavy
equipment;

Personnel will dress in suitable safely equipment to reduce personal exposure (e.g., gloves,
safety glasses or splash shields, etc.).

11

K-48

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.15926 5 7•'.< ] .• J'J 12 i!J 54 am	Pati lew -i^r

^ CoV	5i! ;>yi	. nkc < V:ur*t\ Rroortitr

Equipment showing gross* conlamittittion or having drill tunings caked or will be scraped off

with a tlat-Wadcd scraper at the sampling. or construction site
Equipment, such 
-------
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SOP-4

SOP Dij.%.' Ffhnuin 200$

GROUNDWATER WELL SAMPLING

1J PUKPOSF. AND SCOPE

The purpose of this document is to define the standard procedure for collecting groundwater
samples from wells for the California Gulch Supcrfund Site. This procedure gives descriptions
of equipment, field procedures, and UA-'QC procedures necossaiy to collect groundwater
samples from wells. The sample locations ami frequency of collection are specified in the
QAPP

TW» procedure is intended to be used, together with several other SOPs, as applicable, including:
SOP 1 DecantaminaHon

SOP 7 Sample Handling, Documentation, and Analysis

2.0	WATF.R SAMPLING PKOCtDUKLs

2.1	Equipment List

Sample Mtlcs, preservatives, sample labels will be obtained from the analytical laboratory
Several extra sample bottles will be obtained in taw of breakage or other problems. Sample
bottles can be cither pre-p reserved or preservatives can be added in the field.

Equipment that may be used during well evacuation:

Well keys

Electronic water level probe

Assorted fouls (knife, screwdriver, etc.)

PVC. Teflon, or stainless steel bailer (bottom filling)

PVC hand pump

Nylon or polypropolene fwpe

Bailer tripod

PVC pump tii.whargt; hose
Gas-powered electric generator
Staiol«s-
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339265 7/31/203 2 ) 0;54 AM
24rfil COV WC59J0'tJW AO '

F*nc» ^ctt-cr
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Calculator
Field notebook
Waterproof' pen

Plastic steeling (for placing aiouud well}

Appropriate health and safely equipment

Equipment that may he used during w ell sampling:

Electronic water level measurement probe

PVC, Teflon, or slainjess steet baiters (bottom filling)

Stainless-steel submersible pump

PVC pump discharge hose

Electric generator

Nylort or polyprupolcue rope or twine
Bailer tripod

pH mete (with automatic temperature caropensation)

Specific conductivity ruder

Plastic squcec h«i[tle filled with deiiiniMid water
Sample bottles

Dedicated jug for holding sample for filtering
Cooler with itc

Polyethylene or glass jar for field measurement samples
Sample labels

Equipment used during sample filtration:

Disposable flltcrware with 0 45-micrc.m filler

Hand pump or peristaltic pump

Tygtm or silicon tubing (2- to 4 ft lengths)

Equipment u*ed during daiontaifiinatioii:

Peioniied or distilled water
Decontamifutjofi buclietwjwuls

Paper towels
Plastic brashes
Sprayers

2.2 Sampling Procedures

This section gives the step-hy-.-itep procedures fi»r collecting samples in ihtr field, Obscrs »tiujis

made during sample collection should he recorded in the field notebook and field data sheet as
specified in Section 2.4 of this SOP.

2.2.1 Decontaminate Equipment

•>4

K-51

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35')265	m'AL'WI; ! il ^4 AM	F*atriea Llrrgfr

ot : :>v 50 DtfiH!	Lake C'ouriv Uftpffit:

Before any evacuation or sampling begins, all well probes, bailers, and other sampling devices
shall he decuntam mated, If dedicated equipment is used, it should be rinsed wilh deionized

water, Dedicated dnwnhok pumps, will not be deeojiimninatad. A discussion of equipment and
personnel decontamination is contained in SOP No. I, Decontamination, and in the site Health
and Safely Plan.

2,2.2 Instrument Calibration

Electronic equipment used during sampling includes & pH meter with temporalure scale, a
conductivity meter and a turbidity meter. Before going into the field, the sampler shall verify
thai all of these are operating properly. The pH and conductivity meters require calibration and
calibration checks every day poor to use. The turbidity meter requires * calibration check by
reading measurements cells of a known value. Calibration times ant! readings will be recorded in
a notebook and/or on Calibration Data Sheet, which are to be kept by the field sampler.

2.2.J Evacuate Well

"Hie fmrfio.se of well purging is lt» remove stagnant water from the well to obtain representative
water from the geologic formation being sampled while minimising disturbance to lite collected
samples. Before a sample in taken, the well will be purged until a minimum of three well easing
volumus have been removed and field parameters have stabilized, or until a maximum of five
well volumes hnvc beta removed, Purging will be considered completed if the well is pumped
or bailed dry. A well should be pumped at a rate no faster than approximately I gallon per
minute if ii has, * tendency to dry up prior to evacuating three casing volumes. Evacuated well
water may tie disposed of at the well site in a manner thai docs not causts Minuff

Before well purging begins, the folly wing procedures are to be performed at each well;

Note the condition of the outer well casing, concrete well pad, protective posts (if present).

and any other unusual conditions in the area around the well.

If bailing place clam plastic sheeting around the well.

Open I he well.

Note lite condition of the inner well cap ami casing.

Measure (to nearest 0.01 fool} and record depth of sialic water level from the measuriiig
point on die well casing and indicate time. Record what the measuring point is (i.e.,
notch tm TKirth side, tup of PVC well casing)

Calculate volume of water in (he well casing in gallons based on feet of water and casing

diameter. (See Section 1.4.3 for calculation of volumes.)

From the above calculation, calculate the three casing volumes to be evacuated.

Obtain an initial sample (which is not retained) from the bailer or purge pump for field
measurements (temperature, conductivity, and pH measurements) and observation of
water quality.

25

K-52

-------
liiiiMniii

359265 7 31 '2'Jl2 U< 54 A\1	UfrRer

2.2 pH unit and
conductivity and temperature readings within =10 percent between consecutive readings
irxiiuiie gixad stability «f the water chemistry, If the chemistry is not swblc, continue
purging up to a maximum of five well volumes, measuring pH and specific contkotitnec
after each uric half well volume.

When evacuating a well using a pump, ihe pump intake should be placed;

for tow recovery wells (wells thai can be pumped dry), place pump intake at bottom of
screened interval.

for high recovery' wells (little drawdown with pumping), place pump at or rfightly
above the middle of the screened ml oval to ensure trne removal of stagnant water from
the well bore.

If the well is bailed or pumped dry during evacuation, it can be assumed that tie purpose of
removing 3 well volumes of water has been accomplished, that is, removing all stagnant
water lhat had prolonged contact with the well casing or air. If recovery is very slow,
samples may be obtained as won as sufficient water is available.

22A Obtain Water Samples

Obtain samples for chemical analysis within 2 hours after purging is completed. if possible. For
slow recovering wells, the tuunple shall he collected immediately after a fiufHeieot volume i*
available (water has recovered to screened interval}. The water quality samples shall be taken
from within the well screen interval.

The following sampling procedure is io be used at each well:

1.	Assemble decontaminated sampling equipment Jf bailers arc used, new nylon or
polypropylene rope will be used for each well for each sampling event. Assemble
the filtering apparatus.

2.	Make sure that sample labels have been filled out for each well.

3 Lower the bailer slowly arid gently into contact with the water in the well Lower
the bailer to the. same depth in (he well each time, within the screened interval.
Retrieve the bailer smoothly and em ply the water in a slow steady stream inks the
containers. If submersible or bladder pumps are utilized to collect samples, hUut
the pump and fill the sample bottles* hi tlesvribcd belcn*.

4. Triple rinse the sample containers with sample water and then fill the sample
bottles. If not enough sample water is available to perform the triple rinse, then at
a minimum a single rinse will be performed and will be rceortM in the field
logbook and/or data sheet Cap the sample containers quickly IF sample bottles
are pre-pres«rv«L fill the sample bottles without riming. Add preservative if the
bottle- is ntrt pre-preserved. Dy not allow the sample containers with preservatives
to overflow, See Section 2,2.5 for details on field filtering.

26

K-53

-------
IHIIMlllill

"*59265	7-v«X<	Fjkif Ct'.utrtv Rec,itd«

5,

Slowly pour an un filtered portion into the sample container for field parameter



(pH, specific conductance, temperature, and turbidity) analyses and perform the



in-field analyses and record.

6

Place samples on tee m a cooler.

7.

Record time of sampling.

R,

Replace and lock well tap.

9,

Complete field documentation.

2.2.5 Filtering Samples

Samples for metals analyses will be filtered during the field sampling event by using a
disposable filter apparatus and pemlaltk nr htmii vacuum pump.

The following procedure is t« he used for filtering:

Assemble fitter device according to manufacturer's mst motions,

IVior to the collection of aliquots, flush the filter with approximately 100 to 200
milliliters of groundwater. Filter sample cither by poursng sample in the top portion of
liltci unit or pumping thiough an in line filler using a peristaltic pump. Sample may also
be filtered by attaching the in-line filter to the submersible pump discharge.

Triple riiwc the iampk containers with filtered sample water and then fill the sample
bottles. If not enough sample: w*ut is available to perform the triple rinse, then at a
minimum a single rtnsc will be performed and will He rcasrttetl in the liehf logbook
and/or ikta sheet Cap the sample containers qukkly. If sample bottles arc pre-
preserved, fili the sample bottles without rinsing. Add preservative if the tattle is. not
pre preserved. Do not allow the sample containers with preservatives to overflow.

Place the used fillet membtonc or disposable filter equipment in a Ziploc* bag for
disposal with the personal protective equipment.

Any reusable filtering equipment will be decontaminated in accordance with SOP No 1.
23 Sample Handling

Sample containers and preservatives are specified in SOP No. ?, Sample Handling,
DtKunicntatkm and Analysis. Samples will be labeled 
-------
1I1IR1IU

359265 MWOi: 11; 54 AM Paflrma

IHurW C">V RS213
-------
Ill ill I ill!l II

359265	;it|; il> 54 AM	Patricia 3ctget

2i| A* 'V Ri;.N 5i < PS»"i r ft	!,,-it < L'ouiity R«i\ niM

Depth fit]) x 0,6528 gai/ft
= gaTlonswdl ctoitug volume

For h-inch welt:

Evacuation Volume |gal| = (Total Depth [ft] - Water 1-evel

Depth {ft]) x 1,4688 gul/ft

= galkxis-wrll trying volume

Multiply the volume of one well casing volume by 3 to obtain the minimum volume of water to
be evacuated.

25

K-56

-------
Ill I II I] 111 II

359265 W3IEB12 10J4AM	I'lMjKr

,»of» GOV nmj»moO	[.AeCw^tyRwrder

afpf.\t>i\ a
GROUNDWATER DATA SHEET

K-57

-------
7/3t>'»l2 10:34 AM	PalticiB Soger

1« COV RS239.50 DKI.W	Lake C oUnty kcco-ilci

(JROLIMOW A 11K DA f A SiHtlt l

BEHEEAH2H

Siimpte Location, _ 	f>*tt	Timc	PitfC	of.

Sanipte Control Number		Samplers' 				

WEATHER coyprrtoNS

Ambient Am* Temperature	. *r H	'FO Nut Mea,Mii«P O

Pteapitatic* Nunc ~ RiinD ShwD Ucav> O Motfcnr* ~ Light O 5uim> O Fully Cloudy O
WELL MEASUREMENTS.iMcagurcaiMm n» {M1J> |

il

(







s

Was at
)

was a mm mMSM. WWiSf
)

Yes ~ No ~	control number.

Yes ~ No ~ («implc control number

31

K-58

-------
lillWII

3^265	7;V,Om; IftW A\1	PaSncwBerper

KofiS f< -v 1KP 5C< ran «1	LiikeCnium Seen:*!

Was a rmsafe $a«pi4 tnlloctei?	Yc-i ONoD I'saapie ci nitre 1 nuintiar

)

Notes:

32

K-59

-------
ilium ii

359265 vmmnmS4Jm mttlmBemer

JlofSI COV W239 50 B®»	tab Corny tUsonkr

SOP-7

SOP Dflfe1; Fc/irwury 20(M

SAMPLE HANDLING, DOCUMENTATION, AND ANALYSIS

hi! 1H RPOSK AM) SCOPF.

The purpose of this document is to define the standard protocols tor sample handling,
documentation, and analysis for the California Gulch Superftmd Site. This procedure is
intended to be used together with other SOPs and is refer eoccd in all SOPs that apply to
sampling.

2.0	PROCEDURES FOR SAMPLE HANDLING, DOCUMENTATION, AND ANALYSIS

2.1	Sample Monti Oca Han and Labeling

Samples collected during monitoring, investigations, or remediation activities will be assigned
unique nam pie identification Ttumhws. Each sample identification number will identify the
organization collecting the sample or lhc program under which it is collected, sampling location,
type of sample, and sampling sequence for each sample. These numbers are required for
tracking (he handling, analysis, and verification or validation status of all samples collected
during monitoring. In addition, the sample identification numbers will be input into the project
database to identify- analytical results received from the laboratory.

Sample identification numbers that arc assigned will be divided into four fields as shown in the
following example:

M -CG W1 -01 -900423

The first field is one character m length unci identifies the company conducting the stmplmg.
The second field is an alphanumeric code identifying the location of the sample and lhc last letter
of this field initicitio the matrix (e.g., CCifVfl indicate? California (iulch Well No. 1, the second
W indicates a water matrix), lhc next field identified is the type of sample being collected; this
is used to identify whether the sample is a primary or grab sample, a composite sample, field
duplicate, field Wank, or equipment rinsatc. 'The final field contains the date in a ycar-motrth-day
format. For example, the sain pit identified above was collected on April 23, 1990.

Each sample that is collected in the field will be labeled for future identification. Sample labels
will be filled out as completely a«» possible by a member up the sampling team prior to the start of
lhc slay's field sampling activities. t'he date, time, sampler's signature, and fht last field of the
sample identification number should not be completed until the sample is actually collected All
sample labels will be filled out using waterproof ink. At a minimum, each label will avium the
following information:

33

K-60

-------
1111II !U lli'll

3<.926S Ml,-20!2M:S4ftM	Patricia Boger

M ur« ci 
-------
	win muni

359265 7-J. iul. Im.54 AM	Patnct:i Berger

)Snf_W Cv:V RI339 50 CSH fti	! sike Cnunlv HfenniSer

chain-(»f-cuxlody seals will be attached to the outside of the cooler to ensure ifaat the cooler

cannot be opened without breaking the seal Final packaging and shipping will be conducted in
compliance with current JAlA Rcsolytiwn 618 and DOT 49 CFR Pan 171 Regulations.

All samples will he shipped for laboratory receipt and analysis wiilnn the holding times specified
in Tabic 2. This may require daily shipment of samples wiii short holding limes..

2.4 Sample Documentation and Tracking

This section describes the information that should be pn.iv ided in field motes unsl sample Chain'
uf-C'ustody documentation.

2.4.1	Pickl Notes

Documentation of observations and data acquired in thv field provide int
-------
JilllMli1!

359265 7.-3|.'2ui: !^:54 A\t	fatnci,. Ht-gc

K, rf ,W < ¦(.! v m:.K 50' Dsn "»'i	Lake Cuuniy Rrcordw

cmciai for resolving future problems if analytical results arc caJlaJ into question and lor
minimizing the possibility of sample mix-up. Initial information concerning collection of rtie
samples will be recorded in the field log book or tin data sleets as described above. Information
on I he custody, transfer, handling and shipping of samples will be rt'cwlcd <>ri a Cham-<>f-
Custody (COC) form.

The sampler is responsible for iniliating and filling out the COC form. The COC will be signed

by the sampler when he or she relinquishes the samples to anyone else. A COC farm will be
completed for each set of water quality samples collected, and will con urn the following
mfunnation:

Sampler's signature aid affiliation
Project number	,

Date and tunc of collection
Sample ideniiticalion number

Sample type
Analyses requested
Number oi'wintainsra

Signature of persons relinquishing custody, dttcs, and times
Signature of persons accepting custody, dates, arid times
Method of >>hipmcnl

Shipping air hill number (if the samples arc shipped)

Any additional instructions to the laboratory.

The person responsible for delivery nf the samples to the laboratory- will sign the COC form,
retain the third copy of the form, document the method of shipment, and send the original and
the second copy of the form with the samples. Upon arrival at the laboratory, (he person
receiving {he samples will sign the COC' form and return the second copy to the Project
Manager, Copies of all (XX documentation will be compiled arid maintained in the central files.
The original COC forms will remain with the samples until the lime of final disposition, After
returning samples for disposal, the laboratory will send a copy of tic original COC to the
Operator, litis will the# be incorporated into the central file*



K-63

-------
1

K-64

-------
K-65

-------
111111111(11

take County Siuswfef

.¦Btaeli. Cloud Mine Tailing Pmfierty

This property is subject to an Environmental Covenant held by
the Colorado Department of Public Health and Environment
pursuant to section 25-15-321, C.R.S.

Resurrection Mining Company ("Reswnrection") grants an Environmental

Covenant ("Covenant") this , day of AflW ...	2011 Ut the HayAnloun

Materials and Waste Management Division of the Colorado Department of Public Health
and the Environment ("the Department") pursuant to §25-15-321 of the Colorado
Hazardous Waste Ad, § 25-15-101, e( seg. The Department's address is 4300 Cherry
Creek Drive South, Denver, Colorado 80246-1530.

WHEREAS, Resurrection is the owner of certain property situated in Lake
County, Colorado, more particularly described in Attachment 1, attached hereto and
incorporated herein by reference as though fully set forth (hereinafter referred to » "the
Property"), and

WHEREAS, pursuant to thai Consent Decree among Resurrection, Newman 1
USA limited ("NewrocnP), the State of Colorado and the United States, which was
entered by the L.S. District Court for the District of Colorado on August 29. 2008 in
Stale, of Colorado v Asaroo Incorporated, ef ai. {"Consent Decree"), Resurrection has

agreed to grant an Environmental Covenant in accordance with the terms thereof.

NOW, THEREFORE, Resurrection hereby grants this Environmental Covenant to
(he Department and EPA as a third party beneficiary, declares that the Property-as
described in Attachment A shall hereinafter be bound by, held, sold, and conveyed
subject to the requirements «t forth below, which shall mn with the Property in
perpetuity aral I* binding fin Resurrection, its heirs, successors and Assigns, and any
persons using the Ituid, ss described herein. As used ia this Environmental Covenant, the
Icon "'Owner" means the record owner of the Property and any other person or entity
otherwise legally authorized lo make decisions regarding the transfer of the Property or
placement of encumbrances on the Property, other than by the exercise of eminent
domain.

!} UacJUstrtctjflaa-

No uses or activities that would in any manner interfere with or adversely affect the
implementation, integrity, or protectivencss of the reclamation and closure actions that
haw been or will be performed or instituted on the property including, without limitation,
revegetated areas, retaining ponds, adits, roads, ditches, pipelines, utility corridors, waste
disposal facilities, tailings ponds, monitoring wells, signs and governmental use

EWVIROKM ENT AJL COVENANT

K-66

-------
IlillMilBI!

359264 "31 <2012 KKC AM	Patriew.Bttger

2of? COV RW-lN WOiOT	T.attCouaty^eairdn

restrictions and controls, shall be allowed. These restrictions wilt not apply to any future
mineral prospecting, exploration or mining activities conducted on the properly in
accordance with the Colorado Mined Land Reclamation Act and implementing
regulations.

2)	lQ*pect!ons

The Department awl EPA as the named third party beneficiary shall have the right of
entry to the Property at reasonable times with prior notice for (lie purpose of determining
compliance with the terms of this Covenant. Nothing in this Covenant shall Impair any
other authority the Department may otherwise have 10 enter and inspect the Property,

3)	Termination.

This Covenant inns with the land and is perpetual, unless terminated or modified
pursuant to this Section or Section 4. Ow ner may request thai the Department approve a
termination or modification of this Covenant. Consistent with C.R.S. 25-15-319( I )(h),
the Department shall terminate ttiis Environmental Covenant in whole or in part when, in
addition to satisfying the requirements pf C.R.S. 25-15-321(3) and (5), Owner provides
the following applicable showings to (he Department;

a.	Restrictions on uses or activities that would disturb or have tie potential to
disturb caps, covers or revcgctated areas, or interfere or have the potential
to interfere with or adversely affect the implementation, integrity, or
protect)veocu of the reclamation actions that have been or will be
performed or instituted on the property shall be terminated if ibe waste in
place within the area proposed for disturbance is removed or response
Facilities on tlie property arc dismantled with the approval of fcPA and the
State.

b.	In addition to the grounds for termination set forth in Suction 1.x, the
Environmental Covenant* shall also be terminuted as to all or part of the
Property if it is demonstrated to the Department that the proposed
termination will ensure protection of human health and the environment,
in Accordance with C.R.S. 25-15*319( l)(h).

Consistent with C.R.S. 25-15-321(6), the Department shall provide to Owner a written
determination on all applications to terminate this Environmental Covenant within 60
days after receipt of such application.

*) MMiicatimi

The Department shall modify this Environmental Covenant in whole or in part when, in
addition to wristying the requirements of C.R S. 25-15-321(3) and (5), Owner

demonstrates to the Department thai lite proposal modification will ensure protection of
human health and the environment, in accordance with C..R..S, 25-15-3I9( I )
-------
Efllllllll

159264 TOUWiaiO-JOAM Mriculfciur

•" COV, RWU5 D® 00	Ufa CW*}¦ Recife

Consistent with CHS. 25-15-321(6), the Department shall provide Owner a written
determination on all applications to modify tilts Environmental Covenant within 00 days,
after receipt of such application,

5)	Conveyances. Withm thirty days (30} after any gram, transfer or conveyance of
any interest in any or all of the Property, the transferring Owner shall .notify the
Department and EPA as the named third party beneficiary of such giant, transfer or
conveyance,

6)	Notice	Owner agree* to incoipnrate cither in full or by reference the

restrictions of this Covenant in any leases, licenses, «r other instruments granting a. right
to use the Property.

7)	Moljfie^on for proposed construction and land use. Owner shall notify tic
Department arwJ EPA as the named third party beneficiary simultaneously when
submitting any application I© a local government for a building permit or change m land
use that would authorize a land use prohibited under Section I.

8)	No Liability. The Department docs no* acquire any liability under Stan: law by
virtue of accepting this Covenant,

9)	Enforcement. The Department and EPA as the named third party beneficiary may
enforce the faros of this Covenant pursuant to §25-15-322- CR.S, awl may file suit in
district court to enjoin actual or threatened violations oft this Covenant.

10)	Notices. Any document or communication required .under this Covenant shall be
seal or directed to:

to ftg PtOTiurtm«LjM-fe^Qvidg£A>:

[appropriate Program Manager or L'njf leathrj

Hazardous Materials and Waste Management Division
Colorado Department of Publ ic Health and the Environment
4300 Cherry Crock Drive South
Denver, Colorado §0246-1530

Njfiijjca to EPA shall be provided to:

EPA Remedial Project Manager
California Gulch Suptrrfund Site

United Stales Environmental Prelection Agency, Region 8

(8EPR-SR)

1595 Wynkoop Street

Denver, CO §0202-1129

K-68

-------
'""Willi

WJ1/3M2 10:50 AM
4ta#1 COV KS4*'foy of

s 2111L

Resurrection Mining Company

By..

Titic: Vtt<

STATE Of

0A-ZtAJ Jei

COUNTY	. -

5 ss:

The foregoing instrument was acknowledged before me this^day of

2011 by,	chalfof Resurrection Mining

C ompany

K-69

-------
IWIJJI/UJ

359264 . mtmu 30:30AM
5 of .7 COV »»S,25

tWrkiiBttfpr

f Ji« County R

	J\*'	hiiL



Noiary Public
Address

My commission expires; ^ l.2»l

Accepted by the Cokmido Department of Publiu Health ami Environment this 'Ic*

pfSjTm%e. , »**/£•

f ^ / ) /Y

Bv: w- / ^-

¦ -'A,

K-70

-------
iiiiiiifiiiiu

J5W64	io so am

6 of? COV RS45 2S DSrtftt

ATTACHMENT 1
TO ENVXRONMENTAti COVENANT
THE PROPERTY

Mineral Survey 'Vumber	Claim N

1536

Cletr Grit

1771

EUa Heeler

2249

Montreal

2619

Slide

3|(»0

American Liberty

MM

Coosttmee

J.191

lane Fugenc

1604

Aimed*

3fi05

las*



Helena

04

Tyrant Lwte

15908

l*dy Alice

K-71

-------
Black Cloud Zone

8 -IS ISO 46CMstera
I ¦ --t	l—1	1	t	I	I

K-72

-------
Figure K-8: 2012 Environmental Covenant for Resurrection Mining Company's Zone B properties

ill

1242261-R8SDM8

STATE OF COLORADO

JOMW H.ctank»pcr, Qomikp

Christopher ff.lMSM, MO, MMf

F>m«r CkV am "•»»• HlJi-jl mucin

P"l	j	<£-** , .zv*,-*. Hk« ~\ib>n	,jn n-> gn un- .t.i.-t =-_# It-A	I **.,4 a-%	.j...

MwJPvMtvU •v1 p»* CWI I*jf mHJw ™|r'vW'tj]l *•» TIW«Mn •>1V *1 * WWlW* ¦BWil Elf (KK)$!IIB ijH 'wOlGfwJCS*

4300CH*nyO>MkDr.a. UMSWrteivkiMeiMlHii
0«w»r. Ccfcxaoo n»IW |1§0 Lm>M.

I ni" n Ci«pJa<«. Cptaradn I'ATJ) (98-X3K

tffftr.tffMiw udche itole.to us

October 10, "2012

GsJondft Dwnitiiwnt
Mid

Hen. Carl Schaefer

Chairman, Board of County Commissi oners

Lake County Government

505 Harrison Avenue

P.O. Box 964

Lcadvilk CO 8046!

RF Environmental Covenant for Resurrection Mining Company's Zone B Properties
Dear Carl,

The enclosed Environmental Covenant for Resurrection Mining Company % Zone B properties has now
been executed by nil parties utxJ filed with the Lake County Recorder

As you know, the Colorado Environmental Covenant statute, C R S. i> 25-15-321 to J27, requires that
local government!* notify the CDPHF when they receive applications affecting I are! use »r development
of land that is subject u> an environment.!! covenant. Irs lum, the CDPHIi must review the proposed
application and provide timely advice to the local government as to whether the application is consistent
with the terms of She covenant or restrictive notice.

Therefore, we respectfully request that you forward the enclosed environmental covenant to appropriate
Lake County Departments to assist them in identifying applications that alTcu itw land use or
development of the parcels described in the covenant.

Please don't hesitate to. contact me or Doug Jami sun with any questions or comments

Sincerely,

Craig Gander
Project Manager

Suptrfund and Voluntary Cleanup Unit
Hazardous Materials and Waste Management Division

ccr Linda Kicfer

liSHI'A Region §

8FPR-SR

1595 Wynkoop St

Denver, CO 10202-1

29

K-73

-------
?!?P7rv~, waawnwAM pb.-(«b^
i >f CvUymdn v.
Alarm !rcc>rp(traled, et at ("Consent Decree"), Resurrection has agreed to grant an

Environmental Covenant in accordance with tic terms thereof

MOW, THEREFORE, Resurrection hereby grants this Environmental Covenant to Ihe

Department with EPA as the third party beneficiary, and declares that Ihe Property as described
in Attachment 1 shall hereinafter be bound by, held, sold, and conveyed subject to the
requirements set forth below, which shall mn with the Property in perpetuity mid be binding on
Resurrection, its heirs, successors and assigns, and any persons using the land, as described
herein. As used in this Environmental Covenant, the term "'Owner" means the record owner of
the Property and any other person or entity otherwise legally authorized to make decisions
regarding the transfer of the Property or placement of encirmhfarces on the Property, other than
by the exermc of eminent domain,

1) Uw. lustrations.

a. No Residential Use, Day Care Centers or Schools, as defined in Section 10, shall
be alia wed on the property. No portions of Parks or Open Space (as defined in
Section 10 below) that are designed or intended to provide a designated play or
lecreatioti area for children shall be allowed. Prohibited play or recreation areaj

?-e* -/Zr

K-74

-------
iii ;i ii Nil i ii if

159747	n r.I am Patricia Ikrzer

: t-r 36 ('(>V Hi20:;m DSG m	T.ak* Recorder

include designated picnic areas, playgrounds, ball fields, sand boxes and similar
«reas. but do not include trail systems or walkways.

b. No use of untreated groundwater fiorn wells located on the property tor drinking,
domestic, or agricultural purposes shall be allowed This covenant docs not
restrict the use of groundwater that is treated to meet then applicable Slate water
quality standards ft* the beneficial use to which the water is bong applied.

Treatment rausi meet any applicable standards that are in place at the time of use.

6, Mo uses or activities that would disturb or have the potential to disturb caps,

covers or other rcvegetatod arras, or otherwise interfere or have the potential to
interfere with or adversely affect ihe implementation, integrity, or protectveness
of ihe response actions that have been or will be performed or instituted cm ihe
property including, without limitation, water treatment plunls, retaining ponds,
adits, roads, ditches, pipelines, utility corridors, waste disposal facilities,
monitoring wells, signs and governmental use restrictions and contnih, shall be
allowed. These resirictiiws will mrt apply to any future mineral prospecting,
exploration or mirttng activities conducted on the property in ucconlance with the
Colorado Mined Land Reclamation Act and implementing regulations,

2)	Jaspssisai,

The Department and EPA as the named third party beneficiary shall have the nght of entry to the
Property at reasonable times with prior notice ftrr the purposu of determining cirtMptiaqce with
the term si of this Covenant. Nothing in this Covenant shall impair any other authority Ac
Department may otherwise have to enter and inspect the Property.

3)	Termination.

This Covenant wins with the land and is perpetual, unless terminated or modified pursuant to this
Section or Suction 4. Owner may request that die Department approve a termination or

modification uf this Covenant. Consistent with C.R.S. 25-15-319{ 1 ){h), the Department shall
terminate this Environmental Covenant in whole nr in part when, in addition to satisfying the
requirements of C.R.S. 25-15-321 (3) and (5), Owner provides the following applicable showings
to tlic Department;

8. Restrictions on Residential Use and other uses sped Red in Section 1 .a shall be

terminated on all or part of the property if Owner demonstrates to the Department
that the concentration of lead in the upper 6 inches of soils on the property for
which termination is sought docs not exceed 3500 parts per million (ppm), and the
concentration of arsenic in the upper 6 inches of soils on ihe property for which
termination is sought docs not exceed 340 ppni. Such demonstration can be made
based on sampling analysis or evidence that the subject property is not impacted
by any releases or threatened releases of hazardous substances. Any soil
sampling conducted for purposes of terminating this Environmental Covenant
shall be conducted in accordance wilb Attachment 2,

7Z1-1

K-75

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359747 ICKttQl2 ] ] .0! AM Pauiciu Bcmer
3 «t 36 C< >V K 1302.00 DHMQ	Ltiki^ Cranty Rewctei

b,	Restrictions on using untreated groundwater from wells locaiod on a]] or part of
die property for thinking, domestic, or agricultural purposes shall be terminated it-
Owner demonstrates lo the Department that concentrations of the constituents

. listed in Table 1 of Attachment 3 in the subject groundwater do nut exceed State
water quality standards for drinking, domestic, or agricultural purposes existing at
the lime of application. Current water quality standards are set forth in Tabic 1 of
Attachment 3. Any ground water sampling conducted for purposes of terminating
this Environmental Covenant shall be conducted in accordance with Attachment
3.

c.	Restrictions on uses or activities that would disturb or have the potential to disturb
caps, cover* or mnvegctalcd areas, or interfere or have the potential to interfere
with or adversely affect the implementation, integrity, or proteciiveness of (he

response actions that have been or wilt be performed or instituted on the property
shall be terminated if the waste in place within the area proposed for disturbance
is removed, or response facilities on the area proposed for disturbance are
dismantled with the approval of EPA and the State.

J, In addition to the grounds for termination set forth in Sections 3.a and 3.b, the

Environmental Covenants shall also be terminated as to all or part of the Property
if it is demonstrated to the Department that the proposal termination will ensure
protection of human health and the environment, in accordance with C.R.S. 25-
15-319(1 In-
consistent with C H S. 25-15-321(6), the Department shall provide to Owner a written
determination on all applications to terminate an Environmental Covenant within 60 day* after
receipt of such application.

4) Modifications.

Consistent with C-R.S- 25-!5-3l9( 1 Mi), the Department shall modify this Environmental

Covenant in whole or in part when, in addition to satisfying the requirements of C.R .S. 25-15'
321{31 and (5), Owner provides the following applicable showings lo the Department:

a.	Restrictions on Residential Use and other uses speeifled in Section I .a shall be
modified on all or port of the property if Owner demonstrates to the Department
that portions of the subject property, where cither soil lead levels exceed 3500
pprn or soil arsenic levels exceed 340 ppm, will be covered by a minimum of two
inches of asphalt, pavement or concrete, or other s tinctures that prevent human
exposure to the soil.

b.	Restrictions on using untccatcd ground water from wells located on all or part of
the property for drinking, domestic, or agricultural uses shall be modified to
eliminate the restriction against one or more of these uses, if Owner demonstrates
to the Department that concentrations of the constituents listed in Table 1 of



K-76

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359747 Wl,'>jt2 11 Ait A\{ Patricia Bagcr
¦»^v« cov R*2fCw mm<»>	bbemrlMb

Attachment 3 in the subject groundwater do not exceed State water qualify
standards in existence at (he time of the application for the beneficial use that
would be allowed under Ihe modification. Current water quality standards are set
forth in Table 1 of Attachment 3, Any ground water sampling conducted for
purposes of modifying this Environment*! Covenant shall be conducted in
accordance with Attachment 3,

c. In addition to the grounds for modification set forth in Sections 4,a and 4 b, the

Environmental Covenants shall also be modified as to all or part of the Property if
it is demonstrated So the Department that the proposed modification wilt ensure
protection of human health and the environment, in accordance with C.R S. 25-
15-319(1)00.

Consistent with C.R.S. 25-15-321(6), the Department shall provide Owner a written
determination on all applications to modify an Environmental Covenant within 60 days after
receipt of such application

5)	Conveyance. Within thirty days (30) after any grant, transfer or conveyance of any
interest in any or all of the Property, the transferring Owner shall nott fy the Department and EPA
as the named third party beneficiary of such grant, transfer or conveyance.

6)	Notice to Lessees. Owner agrees to incorporate either in full or by reference the
restrictions of this Covenant in any leases, licenses, or other instruments granting a right to use
the Property.

?) Notification for proposed const metion and land use. Owner khalt notify the Department

and EPA as the named third party beneficiary .simultaneously when submitting any application to
a local government for a building permit or change in land use that would authorize a land use
prohibited under Sections I a or I x.

8)	No Liability. The Department doe* not acquire arty liability under Slate law by virtue of
accepting this Covenant.

9)	Enforcement. The Department and EPA as the named third party beneficiary may
enforce the terms of this Covenant pursuant to §25-15-322, C.R S., and may file suit in district
court to enjoin actual or threatened violations of this Covenant.

10)	Notices. Any document or communication required under this Covenant shall be seal of
directed to:

N0!iiallsJ^£JBeT'iniS£BLg]liiLb£J>"'vtdcd to:

{appropriate Progr/tm Manager or limit leader]

Hazardous Materials and Waste Management Division
Colorado Department of Public Health and Ihe Environment
4300 Cherry Creek Drive South

4

K-77

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Denver, Colorado 80246-1530

FIS' aw SSS8 ST BX3!—.

Notices to EPA shall be provided to;

EPA Remedial Project Manager
California Gulch Superlund Site

United States Environmental Protection Agency, Region 8

(MEI'R-SR)

1595 Wymkeop Street

Denver, CO 80202-1121)

NwU.£^i^^ui.rffitHa5KaH. he prwdedlc:

Law Department

Resurrection Mining Company
1700 I .iireoln Street, Suite 3600
Denver, CO 80203

And

Director of Reclamation and Closure
Resurrection Mining Company
1700 Lincoln Street, Suite 3600
Denver, CO 80203

Either party may change its designated notice recipient upon 5 days prior to notice tu the other
party.

11) Definitions,

"Day Care Center'"' means facilities that provide care, protection and supervision for
children on a regular basis away from their primary residence for less than 24 hours per day.

1)	Examples. Examples of Day Care Centers include preschool*, nursery schools,
and; latch key programs "Child Care Center*," as defined inC'.R S. §26-6-102(1), arc classified as
"day care" uses.

2)	Exceptions. Day Care Centers do not include facilities, operated in connection
with an employment use, shopping ©enter or other principal use, where children are cared for
while parents or guardians are visiting the premises Or io the immediate vicinity for a limited
period of. time

"Parks and Open Spaces" means areas consisting mostly of« vegetative landscaping or outdoor
recreation, community gariens, or public square*, and include open areas designed and
developed for use by the occupants of. a proposed development and by other persons, fur uses

5

¦?4jnL

K-78

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!5?2F . EI®01-?11''®! m p*"1

OOV kXSBiM) lltW	Lake County Recorder

including but not limited to recreation, parks, and grcraWts, The lamia tend to have few
wmctures

t) Examples, Examples of Parks and Open Space include parks, golf courses,
public squares, plazas, playgrounds, ball fields, recreation anas, botanical gardens. and nature
preserves.

"Residential Use" means stmeturcs or facilities used for Household Living or Group Living, as
defined Wow,

1 Household Living.

A- Household Living is characterized by the residential occupancy of a
dwelling unit by a household. Tenancy is arranged on a flnotith-to-nronth

or longer basis.

B. Examples, Uses include living in houses, duplexes, triplexes, Fourplcxcs
and other multidwcUing stmciures, retirement earner apartments,
manufactured housing and other structures with self-contained dwelling
units

C Exceptions. Lodging in a dwelling unit or where less than two thirds of
the units are rented on a monthly or longer basis is considered a hotel or
motel use and not residential.

2) Group Living,

A, Group Living is characterise*! by the residential occupancy of a structure
by a group of people who do nol meet the definition of Household Living.
Tenancy is arranged on a monthly or longer basts, and the size of the group
may be larger than a family.

B- Examples The Group Living category includes assisted living facilities,
treatment facilities, nursing homes and other institutions and arrangement#
providing care or boarding for a group of unrelated individuals.

t_ Exceptions.

1.	Lodging where tenancy is generally arranged tor periods of
less than 30 days is. not considered to be residential.

2,	Facilities for people who are under judicial detainment and under
the supervision of swom officers are not considered residential.

"Schools"' means public ami private schools at the primary, elementary, middle, junior high, or
high school level that provide state-mandated basic education, including associated play areas,

§

.^= _	 	 __-==-,

K-79

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359747	UVI/iO;2 11 01 AM	ttcncii Drrgcr

? of 36 C'jv RSJM 00 T Vl$\ N«»T^Kc

. „	¦»bJJhjkJi,. Jl UH-A.

p(/8LlO /„# Address

My commission expires.

. Y*

Accepted by I he Colorado Department of Public Health and Environment this day of

.	L~ ¦ J-1 .%-* r~ —* JOHlSr-



K-80

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J 59747 IO«'i >jitl5 no". AM

t-QV	CSls.W

ima

P*icii Berber
f-llle CV*jr>ty RcanJrr



/ Cjf



Ry ^ , _

^ 'l'e:	irr . /	)sS-//..J>

STATE OF
COUNTY Of O pJ)jj 9A

) s&:

The foregoing msu mucin was acknowledged before me this j£>. day of >S

on behalf of the Colorado Department of Public Health and

I he foregoing msu mucin
^2&_by Cjt&&J (Khx^rtrnfo)

Notary Nbhc

iotary Nbhc

4< '-frlO C.M-4/lt^	sO.4 > C

Address	/

^ . ^T/l) i

My commission expires: CJCrjkj/,S~

7n-, x.

K-81

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illllllllll

)747	i II 01 am	Paftfcw.Btoger

36 OOV t$2lSi>#0 OSOtf)	take County Sccarter

ATTACHMENT 1
TO ENVIRONMENTAL COVEN Aft?
THE PROPER IV

Claim N»b«

Mineral Survey Number

217

Swns

214

Seventy-Sin

3f»

Wm Moycr PIkct

Ml

Thompson PUoct

m

Robtnscn i'tacrr fall less tract 3,2,3)"

in

Motown Placer Ttwi J

430

MoiHginmery

441

IVtike

442

Thcmti Starr

443

GoocfcU

455

Uncle Sim

457

Eliza

460

Hope

4fif

Qunftzik*

475

Swamp Angel

490

Gilt Edge

501

Wild Ctt

518

Little Johnny

545

Little Slell*

5«

Ocahiia PUlc/

«2

John Leary

643

BMfik Prince

735

McDcrmlih Plater Tract C

749



790

A.V

US

Rubie

m

Black

918

UKler

«*?

Arnold Placer



tan Rack

975

Minnie

989

Ctemrt Tract A

lOJfi

Cta* (> AnwM Placer

1124

Ullle Hiit).I-.:

1326

Capitol

1437

Garden City

WW

Alan

1627

Anlioch

21 ft J

La% Adel*

2291

Charlie B.

22%

Sncbcr

23»

Fortune

23«4

Chapman PUccr Mine Tract 3



AccidetH

.1(104

KJ.

.U*W

Helen

j«ua

Fanny



Golden Gate

9

7-r»->x

K-82

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35W47 »«IOii2H:«AM
War* OOV k«02C"H ?»»:»

Claim .Name

ftl T! r. in ivn fn tl	m, \ — -- •-	.. -.¦. ¦- .

>iiiierai Purvey .MtmlD&r

3A56	Chmmpion

3W	Lupe, Lupc(Na End), l«p*{So, End)

408C!	Gow Plfc.tr

Cache

«*6S	i oup j pjn cf C»chc.H 2V)	Xm«

72M	Boron Kite

UW?	Com«antt

131ft"	Free Coinage

15320	Maljd

17S-4I	Ausable

t M 3fc	Adirondack

IR590	Hand Saw

16H' A M,	Confident

768 A M	Ocean Wiw

Mote: * Enyrojinvent* Covenant wil be
provided on surveyed portion of Robinson

Placer that encompasses the Oevon Gulch
Tailing Impoundment seep collection system
and conveyance channel

10

K-83

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3597**7 K!-- 1-C1H2 I1 
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iiuiun

359747 Irfl'JfhJ 11:0! AM )'Mricnt Sewer

i2of.» COV RKSKUO DRW	Uke Cornty Reeunitf

Prior to soil sampling, a site sampling plan will be developed -and the sampling areas and
sampling locations will be plotted on a site plan. The sitc sampling plan will show the property
boundaries and any existing residential structures, commercial facilities, or improvement,*. The
sampling areas awl sampling locations will be identified cm the site sampling plan. In addition,
any known or suspected deposit's of mine, mill or smelter related materials (tailing, waste rock,
or slag) will also be delineated on the site sampling plan with sampling, locations identified

1.2 Soil Sample Collection and Handling Procedures

Soil samples will be collected using a plastic or stain Iras steel trowel, soil probe, hand auger,
spade or drive sampler. A pick or spatlc may be utilized, as necessary, to loosen the soil for
sample collection. The specific sampling tool utilized will fee dependent on the soil composition
and density. Additional sampling equipment may include stainless steel bowls, measuring tape.

hand-held GPS, plastic sample bags, camera, log book,, pen, pencil, and marker,

At each composite sample location, a subsample will be collected at cadi apes of a triangle
spaced approximately five feet apart. At each subsample location, any loose debris and any sod
or dense vegetation will be removal from an area approximately six inches in diameter. Samples
will not be collected under or immediately adjacent to trees, shrabs «nd «r strictures. A soil
sample will be- collected at the .suite subsample location lo a depth of 0-2 inches and then 2-6
indies using the sampling tool. Approximately the same volume of xnil should be collected at
each sifcampfe location few each deplh The soil from each subsample will be collected into a
separate dean plastic bag or stainless steel bowl for each sample depth interval. For e*ch
composite sample, combine the subsamples from the same depth interval together in a sealed
plastic bag and mix by hand in the sealed bag. Label the plastic bag with the property
identification, sampling area, depth interval, and date of collection. A chain of custody form will
be maintained for all soil samples from the time of collection until its final deposition.

AH equipment used for soil sampling will be dedicated or will be decontaminated prior to sample
collection. Decontamination equipment will include, pump sprayers, spray bottles, deiewtixod
water, phosphate J'rec soap solution, sc/nb brashes, buckets, disposable gloves, elc. Field
personnel will wear disposable polyethylene gloves to avoid sample cross contamination during
the collection of soil samples.

1*3 Imported Soil

Soil imported to a property for use within the upper six inches of the final ground surface will be
sampled to demonstrate that the lead and arsenic concentration* achieve acceptable
concentrations for residential use ami thai the lew! concentrations achieve acceptable
concentrations for commercial use, as defined in Appendix Fl. For up to 1,000 cubic yards of
imported soil delivered to a property, a sample will be collected every 250 cubic yards. For
volumes greater than 1,000 cubic yards, a sample of the imported soil will be collected for every
500 cubic yards.

1.4 Equipment Decontamination

Sampling equipment will be decontaminated between sample collection points, if the equipment
is not disposable, in order to avoid cross contamination between samples. Fteid personnel will

12

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Illlllill

359747	AM Storicui Bafeu

13 of *5 COV Rf»2 00 DSO «	LAe County S

wear disposable gloves while decontaminating equipment. The following procedures will be
followed to' ensure that sampling equipment is decontaminated:

1)	Visually inspect sampling equipment for soil; a stiff brush will be used to remove
any visible material

2)	Wash the field equipment with phosphate fee soap and water, rinse with distilled
water, and air dry or wipe with disposable paper towels

3)	Wafer used for decontamination will be disposed of on site. All disposable items
such as, paper towels, disposable gloves and wash cloths, wilt be deposited into a
garbage bag and disposed of in a solid waste landfill

1.5 Soil Simple Docitmenlation

Field sampling information will be recorded in a field logbook or field sampling forms,
information that will be recorded at each composite soil sampling location will include the
location (e.g. determined by 'hand-held GPS or measured i<» a defined reference point) and
sampling depth interval. The documents to be completed for each composite sample in each
sampling area are:

Site Flan (Plot Plan)

Cha»n-of-Cu siod y transmittal form
Sample lag wxL'or label
Sample master log

All pertinent sampling information will be recorded on a field loghook. Entries will be made in
the field documents in indelible ink, with all corrections consisting of initialed line-out deletions.
Each day's entries will be initialed and dated at the end of each day by the field sampling crew.

At minimum, entries in the field1 log shall include:

Date and time

Site description (i.e., physical address and assessor parcel number)

Description of weather condition*

Names of field sampling crew

Description of site conditions and any unusual circumstances
l.iscaiion of sample site, including map reference
Equipment identification

Details of actual work cfFort, particularly any deviations from the aforementioned

methods
Field observations

Details of photo documentation, if any

K-86

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•j-T't	IW1 Ml211:01 AM	Patricia Reiser

Woflfi COV aS»3.tt>D»W)	Lak« Colfcrfv Rjtvurder

LS Soil Sample Packaging and Shipping

Each sample container will be properly labeled in the field. All containers will be checked for
proper seal and entered by sample number on the chain of. custody form. After collection,
composite samples will be placed in an insulated cooler for storage in the field. Samples will he
shipped to the laboratory in a cooler with ice. The ice in the ctioler will be double-bagged. One
copy of the Chain of custody form will be enclosed in u plastic bag in each cooler containing the
sample identified on the form. 'I"he cooler will he taped shut and custody seals will be attached
to the outside of.'the cooler to ensure that the cooler cannot be opened without breaking the seal.
The cooler will be shipped using an authorized shipping service to the laboratory for analysis.

1.7 Soil Sampling Quality Control

Duplicate samples will be collected and submitted to the laboratory 60 evaluate the precision and
reproducibility of. sampling and analysts procedures. Duplicate samples will tie collected at a
minimum of one for every 10 soil composite samples. The duplicate samples will be collected,
preserved, packaged, and handled in the same manner as the soil samples, No equipment blanks
or field blanks will be collected.

IJ Laboratory Analytical Protocols

The soil samples will be analyzed by the laboratory using methods detailed in Test MctJnxls for
Evaluating Solid Waste, Revised Methods, SW-846. Hie laboratory shall be accredited by the

Colorado Certification Program. F«r Residential Development, samples will be analyzed for
arsenic and lead. For Commercial Development, swl samples will be analyzed for lead, Soil
samples will he tjigusltsd in accordance with SW-846 EPA Method 3050, After digestion, all
samples will be analyzed by EPA Method 6010B.

The report of analytical re$ul1< will include a cover letter from the laboratory identifying the
sample group and any non-complaint quality control results together with the aftbeted samples.
Attached to the cover letter will be a summary of sample results awl a summary of quality

control results. The summary of quality control results will include instrument performance
results such as standard recoveries and blanks results; matrix QC results such as spikes,
duplicate and procedural blanks; and laboratory control standard recoveries.

14

K-87

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359747 ti¥l <1012 I Nil AM I-atom Ocrpr
15 oS 30 COV WaQ.W DfOJW	l*c County fttwmler

ATTACHMENT 3
TO ENVIRONMENTAL COVENANT

grocndwatkr sampling protocols

Groundwater Sampling ami Analysts Plan

This attachment specifics the groundwater sampling procedures for purposes of terminating or

modifying an Rnvironmental Covenant for groundwater use restrictions, as specified in
Appendix Fl. For purposes of the protocol, a "property" is defined as a portion of a claim, an
individual claim or contiguous claims not exceeding 35 acres in total area for which the
groundwater use restrictions of an aquifer arc to be terminated. The Following® sections describe
the groundwater sampling requirements, methods, sample analysis, and quality assurance that
will support such termination or modification. Alternate groundwater sampling procedures ami
analysis methods for a property may be proposed in a site-specific sampling plan for the
property, subject to approval by "the State.

1.9 Groundwater Sampling Requirement*

One groundwater sample will Ik collected from a well completed in the aquifer of the
hydro geologic unit (alluvial, unconsolidated sedimentary deposits, or bedrock) proposed for
beneficial use underlying each property. I or alluvial or unconsolidated sedimentary deposits, the
hydrogeologic unit is defined as the aquifer with the same lithology and within the »c surface
water hydroiogic divide. The bedrock hydrogcologic unit is defined as the aquifer within the
same geologic formation and stmcture. The groundwater use restrictions will be term mated or
modified for a property for Only that aquifer of the hydrologie unit in which the well is
completed.

The groundwater sample from the well will be analyzed for constituents that arc relevant to the
California Gulch Supcrfund Site For which numeric groundwater quality standards have been
established by the Slate for the proposed beneficial use at the time of the application for
termination or modifiisUion of the Environmental Covenant,,hereafter referred to as the Numeric
Standards. The constituents that are relevant to the California Gulch Superfond Site and the
current Numeric Standards are presented in Table 1 for drinking/domestic or agricultural use,
The groundwater in the aquifer will be determined acceptable for the proposed use, and the
Environmental Covenant restricting groundwater will be terminated for the property or modified
to allow a particular beneficial use, if the constituent concentrations ofitlie sample from the well
are less than the Numeric Standards for all beneficial uses (in the event of termination) or the
particular beneiicial use (in the event of modi ft cation).

HO Groundwater Sampling Methods

The groundwater sample from the well will be collected according to the methods described in
SOP No. 4-Grmund Water Well Sampling, Non-dedicated or non-disposable sampling
equipment will be decontaminated prior to collection ofi the sample according to the methods
described in SOP No. 1 -Decontamination. Sample collection documentation, sample

15

K-88

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Ill llini! II;!

359747 IWl.-iSiP II 01 AM	Patricia Ekrget

I6wf« COV &S2o:i»n$nm	1 oke CVUnly RtWif

containment, preservation, identification, labeling and shipping wit] he performed according to
the procedures described in SOP No, 7- Sample Handling, Documentation, and Analysis,

1.11 Laboratory' Analytical Methods

Samples will be analyzed for the parameters for which Numeric Standards have been established
for the proposed beneficial use. Sample container, preservation, and holding times are provided
in SOP No, 7-Samplc Handling, Documentation, and Analysis The laboratory will be required
to process all samples submitted according to the specific protocols for sample custody, holding,
times, analysis, reporting and associated laboratory quality assurance. Laboratory quality
assurance checks will include the use of.blank, spiked, split and duplicate samples, calibration
checks, and interna] .standards. Designated laboratory personnel will be required to ensure that
Q.A/QC procedures arc achieved. The laboratory or labor atones for constituent amalysij must be
accredited by the Colorado Certification Program. Laboratory calculations and data review will
be performed by the laboratory in acamiancc with the procedures described by the analytical
rotihod. The laboratory will review the results of the laboratory Q€ analyses, instrument
calibration and maintenance records, calculations., and the record oi< sample custody (including
holding times) within the laboratory.

Tabic I Groundwater Standards for Beneficial Use



Domestic Water





Supply and





Drinking Water

Agricultural

Parameter

Standards

Standards

Antimony-dissolved

0 006 mji' L



A lumi num -di ssolv cd _ 	

Arsenic dissolved



5 mg'l

O.OI tTIRi'L

.... O.lmg'L

Barium-dissolved

2 0 mg/l,

0.1 mg/L

Beryl Iium-di ssolvod

J1.004 mg/L

Cadm lum-dissnl ved

0.005 mg/L

r oil «#E !

Chloride-dissolved

250 mg/L



Chrommm -dissolved

0 1 mg/l.

0.1 mg/L

(

F luonde -di ssol ved

1,0 m®'L

0.2 mg/L

mg/L

2 mg?'L

iron-dissolved

©J mg/L

5 mg/L

Lead-dissolved

0.05 rag/L

0.1 mg/L

Manganese-dissolved

0.05 mgi'L

0.2 mg.'L

jvf ercury-disso 1 ved

0.002 mg'l.

0 0! mg/l.

Molybdenum-dissolved

0.035 rag/L



Niekel-di®oh*ed

0.1 mg/L

0.2 mg'l

Selenium-diisolvcd

0.05 mg.'L

0.02 mg/L

Silver-dissolved

0.05 mg/L



Sulfatc-dissolvcd

250 mx'L



ThaIlium dissoIvcd

0 002 mg/L



Zinc-dissolved

5 mg/L

2 mg/L

16

K-89

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17

K-90

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35974? Miopia if-til Ma" tw^-n

"*36 Cov RS2Jlno ' i-SSSSJLw*,

SOP-l

SOP Dale; Fetrnmrv 2tm

DECONTAMINATION

1.0	INTRODUCTION AND TVl'ES OF CON T A Ml > ATI ON

Hie purpose of (his tboiitncnt is to define the standard procedure for decontamination associated
with environmental investigation for the California Gulch Supcrfuml Site, Hits procedure is
intended to be used with other SOPs,

IJ Site «Mlfor Staple Crow-Contamiiiatioii

The overall objective of multimedia sampling programs is to obtain samples which accurately
depict the chemical, physical, and/or biological conditions at the sampling site. Extraneous
contaminant materials can be brwugbt onto the sampling location and/or introduced into the
medium of interest during the .sampling program {e.g., by contacting water with equipment
previously conUtllmated al another .vafnplmg site). Trace quantities of these umlamiii
-------
lIURHlll

M9747 IWV301211:Ctl AM Pwriei# Bet*
Is of 36 gov wasmmtmm

1.1,1 Sampling Equipment

The following steps will be used to decontaminate non-dedicated or non-disfxasable sampling
equipment (including reusable filter apparatus):

Personnel will dress in suitable safely equipment to reduce pereonal exposure (c,g,„ latex

gloves, safety glasses, etc.).

Gross contamination on equipment will be scraped oft'at the sampling or const met ion site.
Equipment that will dm be damaged by water will be washed with an Alconox solution or
low-sudsing detergent and potable water and scrubbed with a bnsfle bush Or similar
utensit (if possible). Equipment will be triple rinsed with potable water followed by a
triple nnse with cNoniyisJ or distilled water,

Following decontamination, equipment will be plated in a clean area, on or in clean plastic
sheeting to prevent contact with contaminated soil, IF the equipment is not used immediately. the
equipment will be covered or wrapped in plastic sheeting or heavy duty trash bags to minimize
potential airborne contamination.

2 J,2 Submersible Pumps

If non-dedicated submersible pumps are used they will be decontaminated between wells. The
outside of the pump and hose will be tripled rinsaJ with dcioni/.cd or distillal water. Deionizcd
or distilled water will be pumped through the pump and hose. The volume of defcinizcd isr
distilled water pumped through wilt be at a minimum equal lo three times the volume of fluid
that could be contained by the pump and hose.

2.2.3 Water Level Probes

fcicctnc water level probes will be decontaminated by rinsing with deionized or distilled water or
by wiping the probe during removal with paper towels wetted with tfcnom/.od or distilled water
The water level probe will be placed in a plastic bag after decontamination

2J.A Sensitive Equipment

*

Sensitive equipment that may be damaged by water will be carefully wiped clean using papa-
towels and detergent water or sptay bottle and towel and rinsed with dciomzed or distilled water.
Care will be taken to prevent any equipment damage.

2.2.5 Drilling and Heavy Equipment

Drilling and heavy equipment will be decontaminated at a design*red decontamination area lor
large equipment. The Ml owing steps will be used to decontaminate drilling and heavy
equipment;

Personnel will dress in suitable safety equipment to reduce personal exposure (e.g., gloves,
safety glasses or splash shields, etc).

19

K-92

-------
lliilliil

359747 H'-'l :ir.2 11 m AM	hur.ciaTWr

36 CUV R5202 no DM nn	LsAeCi-.ua1yRi«jr*r

Equipment showing gross contamination or having drill cuttings caked cm will be soaped off

with a (lat-blafCM scraper at ihc sampling «r eonstmethm site
Equipment, such as drill rigs, augers, drill bits, and shovels will be sprayed with potable
water by a high-pressure washer. Care should be taken to adequately clean the msides of
the hollow-stem augers and back hoc buckets.

Following decontamination, drilling equipment will be placed on the clean drill ng and moved to "
a clean area. If the equipment is not used immediately, tt should be stored in a designated clean
ares,

2.2.6	Equipment Leaving the Site

Vchicks used for non intrusive activities shall be cleaned on an as needed basis. Const taction
[equipment such as earth moving equipment, trucks, drilling rigs,, backhoes, trailers, etc., will be
pressure washed at the desi gutted decontamination area before (he equipment is removed from
tie site.

2.2.7	Wastewater

Used wash and nnse solutions may be discharged to the ground at the sampling site
2.2.X Other Wastes

Solid waste* such as paper towels and used filters will be sealed in plastic garbage tags an J
disposed of in a sanitary landfill.

2.3 Documentation

Sampling personnel will be responsible for documenting the decontamination of sampling and
drilling equipment The documentation will be recorded with waterproof ink in the sampler's
field notebook with consecutively numbered pages. The information entered in the field book
concerning decontamination should include the following:

Decontamination personnel

Date

Decwilunination observations

K-93

-------
.159747 WW»1211«AM

2t#fl6 00 V RS.V2.0Q OJOuQO

PMrwiaRcivr
fjkeCMMyRtcwfer

SOP-4

SOP Dan- February 200H

GROUNDWATER WELL SAMPLING

I.® PURPOSE AND SCOPE

The purpose of this document is to define the standard procedure for collecting groundwater
samples from wells for the California Gulch Superfund Site. This procedure gives descriptions
of equipment, field procedures, and QA/QC procedures necessary to collect groundwater
samples from wells. The sample locations and fiequency of collection arc specified in the
QAPF.

This procedure is intended to he med together with several other SOPs, as applicable, including:
SOP 1 Decontamination

SOP 7 Sample Handling;, Documentation, and Analysis

2.0	WATER SAMPLING PROCF.DIJRF.S

2.1	Equipment List

Sample bottles, preservatives, sample labels will be obtained trow the analytical laboratory.
Several extra urn pie bottles will be obtained in case of breakage or other problems. Sample
bottles earn be either pre-preserved or preservatives can be added in the field.

Equipment thai may be used during well evacuation;

Well keys

Electronic water level probe

Assorted tools {knife, screwdriver, etc.)

PVC, Teilon, or stainless-steel bailer (bottom filling)

PVC hand pump

Nylon or polypropolene rope

Bailer tripod

PVC pump discharge hose
Cias-powered electric generator
Stamlcss-stecl submersible pump

pH meter (with automatic temperature compensation)

Specific conductivity meter

Plastic squeeze bottle filled with dcionized water

Polyethylene or glass container (for field parameter measurements)

Chemical-free paper towels or Kim wipes

21

K-94

-------
35974? IOT20I2JI:01AM Mcto'ictpr
22«CJ« COV RS2Q2.0D MM®	Lake Camty fteconter

Calculator

Field notebook
Waterpmofpen

Plwstic starting (for placing around well)

Appropriate hcaitb and safety equipment

Equipment thai may be used during well sampling:

Electronic water level measurement probe

PVC, Teflon, or stainl«s-st«] bailcis (bottom filling)

Stainless-steel submersible pump

PVC pump discharge hose

Electric generator

Nylon or pMlypropolcric rope or twine
Bailer tripod

pH meter {with automatic temperature compensation)
Specific conductivity meter

Plastic squeeze bottle filled with deionized water
Sample bottles

Dedicated jug for holding sample for filtering
Cooler with icc

Polyethylene or glass jar for field measurement samples
Sample labels

Equipment used during ^ajnpli; filtration:

Disposable filterware with 0.45-micmn filter

Hand pump or peristaltic pump

Tygon or silicon tubing (2- to 4 ft lengths)

Equipment used during decontamination:

Ocioaizcd or distilled water
Decontamination buekcts'pails

Paper towels
Plastic brashes
Sprayers

2.2 Sampling Procedures

This section gives the stqp-by-step procedures for collecting samples in the field. Observations
made during sample collection should be recorded in the field notebook and field1 data sheet as
specified in Section 2.4 of this SOP.

2.2.1 Decontaminate Equipment

22

K-95

-------
iiiiuiiiiiiiE

359747 WW»121! :01AM	Baser

y«'36 cc>v KKK&OO mum	Uk* Corny ttoxmte

Before any evacuation or sampling begins, all well probes, bailers, and other sampling devices
shall be decontaminated. If dedicated equipment is used, if,should be rinsed wilh tiekwmed
water, Dedicated ckmnhwle pumps will not be decontaminated. A discussion of equipment and
personnel dexuntarnination is contained to SOP No. 1, Decontamination, and in the site Health
and Sttfety Plan,

2.2J Instrument Calibration

Electronic equipment used during sampling includes a pH meter with temperature scale, a
conductivity meter and a turbidity meter. Before going into the field* the sampler shall verify
that all of these arc operating properly. The pH and conductivity meters require udtbrarion and
calibration checks every day jwtor to use. Tie turbidity meter requires a calibration check by
reading mea-sunrmenis cells of a known value. Calibration limes and readings will be recorded in
a notebook and/or on Calibration Data Sheet, which are to be kept by the field sampler.

2.2.3 Evacuate Well

The purpose of well purging is to remove stagnant water from the well to obuin representative
water from the geologic formal ion being sampled while minimizing disturbance to the collect od

samples. Before a sample is taken, the well will be purged until a minimum of three well casing
volumes have been removal and field parameters have stabilized, or until a maximum of live
well volumes have been removed. Purging will be considered completed if the well is pumped
or bailed city, A well should be pumped at a rate nn faster than approximately 1 gallon per
minute if it has a tendency to dry up prior to evacuating three casing volumes- Evacuated well
water may be disposed of at the well site in a manner thai docs not cause mnoff.

Before well purging begins, the following procedures arc to be performed at each well:

Note the condition of the outer well casing, concrete well pad, protective posts (if present),

ami any other unusual conditions in the area around the well.

If bailing place dean plastic sheeting around the well.

Open the well.

Note the condition of the inner well cap and casing.

Mensure (to nearest 0-01 foot) anil record depth of static water level from the measuring
point on the well casing and indicate time. Record what the measuring point is (i.e.,
notch on north side, top of PVC well casing).

Calculate volume of water in the well casing in gallons based on feet of water and casing

diameter- (See Section 2.4 J for calculation of volumes.)

From the above calculation, calculate the three casing volumes to be evacuated,

Obtain aii initial sample (which is not retained) from the bailer or purge pump for field
measurements (temperature, conductivity, and pH measurements) and observation of
water quality.

II

K-96

-------
Pili1!II SIMM!

3 5974? 10/120 ] 2 H i) I AM Pilncw Berper
24 of .16 0(>V Ri2fi;.00 TJVi'i i	Luke County Rea««kf

Fvacuatc three volumes of water in casing with a'bsriler or pump. Take temperature, specific
conductance, «nd pH measurements after evacuation of each well volume to iron linn that
the water chemistry has stabilized Generally. pH values within ±0.2 pll unit awl
conductivity and temperature readings within ±10 percent between consecutive readings
indicate good stability of the water chemistry, [f the chemistry is not stable, continue
purging up to a maximum of live well volumes, measuring pH and specific conductance
after each one half well volume.

When evacuating a well using a pump, the pump intake should be placed:

for low recovery wells (wells that can be pumped dry), place pump intake at bottom of
screened interval,

fof high recovery wells (little drawdown with, pwiping), place puinp at or slightly
above (he middle of (he screened interval to ensure the removal of stagnant water from
the well bore.

If the well is bailed or pumped dry during evacuation, it can be assumed that the purpose of
removing 3 well volumes of water has beer accomplished, that is, removing all stagnant
water that had prolonged contact with the well casing Of air, If recover)-' is very slow,
samples way be obtamod as soon as sufficient water is available.

2>2.4 Obtain Water Samples

Obtain samples for chemical analysis within 2 hours after purging is completed, if possible. For
stow recovering wells, the sample shall be collected immediately after a sufficient volume is
available {water has recovered to screened interval), The water quality samples shall be taken
from within die well screen interval.

The following sampling procedure is to be used at each well:

1.	Assemble decontaminated sampling equipment. If bailer* are used, new nylon or
polypropylene rope will be used for each well for each sampling event. Assemble
the filtering apparatus

2.	Make H-ure chat sample labels have been filled out for each well.

3.	Lower the "bailer slowly and genlly into contact with the water in the well. Lower
the bailer to the same depth in the well cadi time, within Ac screened interval.
Retrieve the bailer smoothly and empty the water in a slow neady stream into the
containers- If submersible or bladder pumps are utilized to collect samples. Stan
the pump and fill the sample bottles as described below.

4.	Triple rinst the sample containers with sample water Mid then fill the sample
bottles. If nut. enough sample water is available to perform the triple rinse, then at
a minimum a single rinse will be performed and wilt be recorded in the field
logbook and/or data sheet Cap the sample containers quickly. If sample bottles
are pre-preservod. fill the sample bottle* without rinsing. Add preservative if the
bottle is not pre-preserved. Do not sdlow the sample containers with preservatives
to overflow. See 'Section 2,2.5 for details on field filtering.

24

K-97

-------
liHifJI

35974? 1 •>' i i; 11 -oi AM	Pimricn Bcrger

3^ of .*!> CU\ RS2DI IJV! >'*I	! .akc ("ourtv R«r: Jt'f

5.	Slowly pour so unfiltered portion into the sample container for field parameter
(pH, specific conductance, temperature, and turbidity) analyses awl perl'vrui the
in-field analyses and record,

6.	Place samples on ice in a cooler.

7.	R ecord lime of sampling.

I. Replace and lock well cap.

9. Complete field documentation.

2,2,5 Filtering Samples

Samples for metals analyses will be filtered during the field sampling event by using, a
disposable filter apparatus and peristaltic or hand vacuum pump.

The following pmcedure is to be used for filtering;

Assemble filter device according to manufacturer's instructions,

Prior to the collection of aliqiiois, flush the filter with approximately ltMi to 200
milliliter* of groundwater. Filter sample cither by pouring sample in the cup portion of

filter unit or pumping through an in line filler using a peristaltic pump, Sample may also
be filtered by attaching the in line filter to the submersible pump discharge.

Triple rinse the sample containers with filtered sample water and then fill the sample
kittles, [f not enough sample water is available to perform the mpk rinse, then at a
minimum a single rinse will be performed and will he recurdtsd in the field logbook
and/or data sheet. Cap the sample containers quickly. Ifisamplc bottles arc pre-
prescrvod. fill lie sample bellies without rinsing. Add preservative if the bottle is twt
prc-preserved. Do not allow the sample containers with preservatives to overflow,

Place the used filter membrane or disposable filter equipment in a ZtpJoc* bag for

disposal willi the personal protective equipment.

Any reusable filtering equipment will be decontaminated in accordance with SOP No. I.
2 J Sample Handling

Sample containers and preservatives are specified in SOP No, 7, Sample Handling,
Documentation and Analysis, Samples will be labeled and handled as described in SOP No, 7,

2.4 Documentation

2.4,1 Groundwater Data Sheet

A groundwater data sheet for groundwater samples (Appendix A) will be completed at each
sampling location. The data sheet will be completely filled in. If items on the sheet do not apply

K-98

-------
¦mm

*59747 . 1 Rrvwda-

to a specific location, the item will be labeled as not applicable (NA). The information on the
data sheet includes (he following:

Well number

Date and lime of sampling
Person performing sampling
Depth to water before sampling
Volume of water ev acuated before sampling

Conductivity, temperature, ,irxt pH during evacuation (note number of well volumes)

Time samples are obtained

Number of samples taken

Sample identification Humberts)

Preservation of samples

QC samples taken (if any)

How the samples were collected (i c„ bailer, pump, etc,)

2.4,2 Field Notes

Field notes shall be kept in a bound field book. The following information will be recorded
using waterproof ink:

Names of personnel

Weather conditions

Date and time of sampling

Location and well number

Condition of the *ell

Decontamination information

Initial static water level and total well depth

Calculations (e.g., calculation of evacuated volume)

Calibration information

Sample methods, or reference to ihc appropriate SOP
2.43 Well Volume Calculations

The following equation shall be used to cakalate th« volume of water to be removed during well

evacuation.

For 2 inch well:

Evacuation Volume (galJ = {Total Depth [ft] - Water Level

Depth [ft]) x 0.1632 gat/ft

« gal Ions.'1well casing volume

For 4-inch well:

Evacuation Volume [gal] — (Total Depth [ft] - Water Level

26

K-99

-------
For 6-irich well"
Evacuation Volume [gal]

35974? wiamm am

27 of M COV RS302.00 D40.O5
Depth [ft]) x 0.6528 gal/fl
gallons/welt casing volume

(Total Depth [ft] - Water Level
Depth [ft]) x 1-4688 gal/ft

gatlons/wcl! casing volume

Patncw Berger

Lakt CotMy R«rfer

Multiply the volume of one welt casing volume by 3 to obtain the minimum volume of water to
'be evacuated.

27

K-100

-------
inimi

35974? I"! WI2 S 1.01 AM Ftfnc* n^e,

MafM COY RSXC.f») imC«	t*eC««nlfftmHfcf

APPENDIX A

groundwater data shee i

21

K-101

-------
amsmam

Sample Location	

$sa «,v isgsi'jfflf

GROUNDWATER DATA SlfF.ET

Date		 Time	Piute of

LAeCoiiiy iUwanler

Sample Conlrri Mnnfcf^

. SaoipLcrv

lgATHER....C.QIiBmCM

Ambient Air I cmpr/amit.		 "C O „ °F O N« Mtaawred' O

Prtsipiaiion: Norw-Q RainO Snow ~ Heavy ~ Modci* O Ugh D Sunny~ Partly Cloudy D
WiLLMIMiaail ' ¦¦ :%1' ¦ ¦ ' --¦¦'.J. 3r._-- r ,g_j_ PVC eaaitfl}

t*p«h lo Sunt W«tr _ .	 	feet Twtai Depth of W«U:„

--inch 0.1fi3gal/fi 4-mch !lCi*» gal'i fi-irnrh- l.€?gal'ft
I Casing Votiwne 	 	gallura	3 C u

feet Fas ©f watts:

TVpih PUTnp Inwallrd 			 ^ fcrt Vciuinr water purg«l

	giUotw

.ftiltw

Wei pu,T!»j wall

HELD PARAMETER MfcASL'RtMfcN 1"S DURING Pl.'RGlNG

Tone

Volume
Cjtailons)

PH

Cond

(p&'cm)

Temp."

•CD
•FQ

T«b>d»ty

{visual
estimate)

-

a

Sample
Dale

™—™.3 — J 1g

tropic J * omifi&c

Time I (gallons)

.pi

Cn»r*l
(liSi'cm)

Temp. I

TvobtdHylMU) 1



I







Was a duplicate	cailcetsed?

)

'Was a fiiM blink wHeetrf?

Yes ~ No ~ (naraptc control m*

Y<"< D No ~ (simple wnUwt numhrr_

29

K-102

-------
IlllilUlfl

35§747 WVI0012 11:01 AM Wjk-u Hctmct

.16 if IS mv 1S»2,® DSrj.i®	X^OoSn^Rasonfcr

Wa,« nr-vj# *mpfe a tircttd?	Ves O N» ~ (unfit caorol liiini		

)

Notes:

30

K-103

-------
iinniH

359747 Wl«!2ll:fl»,«

JlufJfi OOV BMW MmiO	Uta Cwm^eewdw

SOP-7

SOP Dale: February 2008

SAMPLE HANDLING, DOCUMENTATION, AND ANALYSIS

1,0 PURPOSE AND SCOPE

1Ti« purpose of this document is to define the standard protocols for sample handling,
documentation, and analysis for the California Gulch Supar&nd Site. This procedure is
intended to be used together with other SQPs and is referenced in all SOt's thai apply to
sampling.

2.0	PROCEDURES FOR SAMPLE HANDLING, DOCUMENTATION, AND ANALYSIS

2.1	Sample Identification and labeling

Samples collected during monitoring, investigations, or remodtafi«n activities will be assigned
unique sample identification numbers Each sample identification number will identify the
organization collecting the sample or the program under which it is collected, sampling location,
type of sample, and sampling sequence for each sample, These numbers are required for
tracking ihc handling, analysis, and verification or validation status of all samples collected
during monitoring In addition, the sample identification numbers will be input into Ihc project
database to identity anal>1 teal results received Horn the laboratory.

Sample identification numbers that arc assigned will be divided into four fields as shown in the
following example:

M-CGW1 01-900423

The ft nil field is one character in length and identities the company conducting the sampling.
The second field is an alphanumeric code identifying the location of the sample and the last letter
of this. field indicates the matrix, (e.g., CGMI indicates California Gulch Well No. I, the second
W indicates a water matrix). The next field identified is the type of sample being collected, this
is used to identify whether the sample is a primary or grab sample, a composite sample, field
duplicate, field blank, or equipment rinsatc. The final field contains the date in a year-month-day
format. For example, the sample identified above was ailfae-tad ik» April 23, 1990.

Each sample that is collected in the field will be labeled for future identification. Sample labels
will be filial out as completely as possible by a member of the sampling team prior to the start of
the day's field sampling activities. The date, time, sampler's signature, and the last field ulthc
sample identification number should not he completed until the sample is actually collected. All
sample labels will be filled out using waterproof ink. At a minimum, each label will contain the
following information:

31

K-104

-------
iniiniiRini

j«9?47	ifMflfiM MAI #»t	hKfK-*'w-^r

l2cf36 CoV saw W,W	UiU-1 nuntyR«e:ir«ler

Sampler's company affiliation;

Site location;

Sample identification;

Date and time of sample collection;

Method of preservation used;

Sample matrix; and

SwmfJer's initials.

2.2	Sample Containers, Preservatives, and Holding Times

2.2.1	Sample Containers

Proper sample preparation practices will he observed to minimize sample contamination and
potential repeal analyses due So anomalous, analytical results. Prior to sampling, commercial]y-
cicancd sample containers will be obtained torn the analytical laboratory. The bottles will be
labeled as described in the previous section to indicate the type of sample and sample matrix to
be collected Sample battles can be either pr«-preserved from the laboratory or preservatives can
be added in the field Airing sample collection.

2.2.2	Sample Preservation

Samples are preserved in order u> prevent or minimize chemical changes that could occur during
transit and storage Sample preservation should be performed immediately upon sample
collection to ensure thai laboratory results are not com promised by improper coordination of
preservation requirements and holding times, Samples will be preserved immediately and stored
on ice ia coolers prior to shipping. Sample preservation requirements are based an the most
current publication of 40 CFR, Pari 136-3 and. are provided in Table I,

2.2.3	Sample Holding Times and Analyses

Sample holding times are established to minimize chemical changes in a sample prior to analysis
andA>r cxtr*aiun. A holding time is defined as the maximum allowable time between simple
collection and analysis and/or extraction* based on (he nature of the unalyte of interest and
chemical stability factors. Holding times applicable for analytes arc listed, in Table I. Samples
should be sent to the laboratory as soon as possible after collection by band delivery or an
overnight courier service to minimize the possibility of exceeding holding times.

For most samples, preservation by cowling to -1°C is required immediately after collection while
the samples are held for shipment and during shipment to the laboratory.

2.3	Sample Preparation and Shipping

After collection, samples will be labeled and prepared as described in the previous discussion,
and placed on ice in an insulated cooler. The sample containers will be placed in re-closeable
plastic storage bags. Samples will then be placed right side up in a coaler with ice for delivery to
the laboratory. The ice in the cooler will be double-bagged. The cooicre will be taped shut and

32

K-105

-------
359747 J*V2M 211:01 AM mm Bmm

rov «,»•#	f «k« Gotuty fcsasniir

chain-vf-custody seals will be attached to tie autstde of the cooler to ensure that the cooler
caanoi be opened without breaking the seal, Final packaging and shipping will be conducted in
compliance with current I ATA Resolution 618 and TOT 49 CFR Pari 171 Regulations.

All samples will be shipped for laboratory receipt and analysis within the holding times specified
in Table 2. This may require daily shipment of samples with short holding times.

2.4 Sample Documentation and Tracking

Thii section describes the information that should be provided in field notes and sample tbaim-
of-Custody documentation.

2.4.1	Field Notes

Document at km of observations and data acquired in the field provide information on sample
acquisition, field conditions at the time of sampling, and a permanent record of field activities.
Field observations and daia collected during routine monitoring activities will be recorded with
waterproof ink in a permanently bound weatherproof field tag book with consecutively
numbered pages or on field data sheets as specified in tie project SOP?.

Field notebook and/or data sheet entries will, at a minimum, include the information listed
below. Relevant SOPs should be consulted to supplement this list.

Project name;

[xxration of sample;

Data and time of sample collection;

Sample identification numbers;

Description of sample (matrix sampled);

Sample depth (if applicable);

Sample methods, or reference to the appropriate SOP;

Field observaiiotu;

Results of any field measurements, such as depth lo water, pH. temperiTure, specific
oonductoice; and

Personnel present.

Change* or deletion"; in the- field bc*>k or on the data sheets should be recorded with a single
strike mark, and remain legible. Sufficient information should be recorded to allow the sampling
event to be reconstructed without having to rely on the collector's memory.

All field books will be signed on a daily basis by the person who has made the entries Anyone
making entries in another person's field book will sign and date those entries,

2.4.2	Sample Chain-Of-Custody

During lick! sampling activities, traceability of the sample must be maintained from the time the
samples arc collected until laboratory data are issued. Establishment of traccability of datet is

K-106

-------
til ill! II ll!l

%^9747 H.VU2fll2 ; 1 -fit AM	Patneia Brtfrr

jlrf.V- CCA" KS202.MI FSJ.'JJ	Lake Court v Rewrite

cmcial for resolving future problems jf analytical results are called into qycsibn and for
minimizing the possibility of sample mix-up. Initial information concerning collection of the
samples will be recorded in rhc field log book or on data sheets as described above. Information
on ihe custody, transfer, handling and shipping of samples will be recorded on a Chain-of-
Custody (COC) form.

The sampler is responsible for initiating and filling out the C'QC form. The COC will be signed
by the sampler when he or she relinquishes the samples 1o anyone cisc. A COC form will be
completed for each set of wafer quality samples collected, and will contain (he following
inlbimstion:

Sampler's signature and affiliation

Project number

Date and time of collection

Sample identification number

Sample type

Analyses requested

Slumber of containers

Signature of persons relinquishing custody, dates, and times
Signature of persons accepting custody, dates, and times
Method of shipment

Shipping air bill number (if the samples arc shipped)

Any additional instructions to the laboratory,

The person responsible for delivery of the samples to the laboratory will sign the COC" form,
retain ihe third copy of the form, document the method of shipment, and send the original and
(he second copy of the form with the samples., Upon arrival at Ac laboratory, (he person
receiving the samples will sign the COC form and return the second copy to Ihe Project
Manager. Copies of all COC documentation will be compiled and maintained in the central tiles,
The original COC fiwis wilt remain with the samples until the time of final disposition. After
returning samples for disposal, tie laboratory will send a copy of the original COC to the
Operator. This will then be incorporated into the central files.

14

K-107

-------
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K-108

-------
35974? Ki 1391211 «1 AM
Irioftf 00\ RS2r£w Dfc>i*i

KauKia Hcr^s;
l.jrfw i.'ounli Rfcertkr

K-109

-------
Figure K-9: 2012 Environmental Covenant for Resurrection Mining Company's Zone C properties

1242262. RbSdS

STATE OF COLORADO

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October 10T 2Q12
Hub Carl Schaefcr

rhnirman, Hoard of County Commissioners

Lake County Govern mem
503 Ham son Avenue
P.O. Box 964
l.eadviHe CO 80461

RE: Environmental Covenant for Resurrection Mining Company's Zone C Properties	,

.Dear Ctrl,

The enclosed Environmental Covenant for Resurrection Mining Company's Zoat! C properties has now
been executed by all parties and filed with the l,ake County Recorder,

As you know, the Colorado l-jivirmwucniai Covenant statute, C.R.S. § 25-15«321 to 32?, requires thai
local governments notify the CDPH1: when they receive applications nffaiing land use or tfcvrfupmcM
of land thai is subject to an environmental covenant Jn turn, the CDPHE musi review the proposed
application and provide timely advice to the lt?«al government us to whether the applicant* is consisted,
with (he terms of the covenant or restrictive notice.

Therefore, we respectfully request that you forward the enclosed environmental covenant to appropriate
Lata* Ccunly Departments tit assist ihern in identifying applications that atl'ect the land use or
development of the parcels described in the covenant.

Please don't hesitate to contact me or Doug Jamison with any questions or comments.

Sincerely,

Craig Gender	Linda Kiefcr

Project Manager	"	USF.PA Region 8

Superfumd ami Voluntary Cleanup Unit	8KPR SR

Hiuarduus Materials and Waste Management DiviM«n	1595 Wynkoop St

Denver, CO 80202-1129

K-110

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Environmental Covenant for Zone C Property

This property is subject lo aa Environmental Covenant held by she
Colorado Department of Public Health and Environment pursuant
to section 25-15-321, C.R.S.

EBTVIRQWMF.N'TAL COVENANT

Resurrection Mining Company l"Resurrection") grants an Fnvjrvm mental Covenant

("Covenant") this 2tlz day of		, 2012 to the Hazardous Materials and

Waste Management Division of the Colorado Department of Public Health and the Environment
("the Department") pursuant ro § 25-15-321 of the Colorado Hazardous Waste Act, § 25-15-101,
tai se.q. The Department'! address is 4J00 Cherry Creek Drive South, Denver, Colorado 80246-
1530.

WHEREAS, Resurrection is the owner of certain property situated in Lake Comity,

Colorado, more particularly described in Attachment 1, attached hereto and incorporated herein

by reference as though fully set forth (hereinafter referred to as "the Property"); and

WHEREAS, pursuant to that Consent Decree among Resurrection, Newmont USA
Limited ('"NcwraonCh the State of Colorado and the United States, which was, entered by the
U.S. District Court for the District of Colorado on August 29, 2008 in State of Coforadu v.

Asurw Incorporated* ft a I. ("Consent Decree"), Resurrection has agreed to grant an
Environmental Covenant in accordance with ihe terms thereof

NOW, THEREFORE, Resurrection hereby grants this Environmental Covenant to the
Department w ith EPA «S a third party beneficiary, and declares that the Property as described in
Attachment I shall hereinafter he bound by, held, sold, arri conveyed subject to the requirements
-set forth below, which shall mn with the Property in perpetuity and be binding oil Resurrection,
its heirs, successors and assigns, and any persons using the land, us described herein. As used in
this Environmental Covenant, the term "Owner" means the record ovmcr of the Property and any
other person or entity otherwise legally authorized In make decisions regarding the irmsfer of the
Property or placement of encumbrances on the Property, other than by the exercise of eminent
domain.

I) Use Restrictions.

No use of untreated alluvial groundwater frvro wells located on the property within 500 feet uf
California Gulch for drinking, domestic, or agricultural purposes shall be allowed. This covenant
does not restrict the use ofgroundwater thai is treated to meet then applicable State water quality
standards for the beneficial use to which the water is being applied. Treatment must meet any
standards that are in place at the time «f use.

I

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35974S K-*' 1 '2U12 11 »U:1 AM Patricia BcTjKr

: of » COV R| ] 5IMj OSillft	County Kmwfer

2)	Inspections,

The Department and BP A as the named third party beneficiary shall have the right of entry to the
Property at reasonable times with prior notice for the purpose of delcrmming compliance with
{he terms of this Covenant. Nothing in this Covenant shall impair any other authority the
Department may otherwise have to enter and inspect the Property.

3)	Termination.

This Covenant mns with the land and is perpetual, unless terminated or modified pursuant to this
Section or Section 4. Owner may request that the Department approve * teimhialion or
modification of this Covenant. Consistent with C.R.S. 25-15-.1l9(t)(h), the Department shall
terminate this Environmental Covenant in whole or in part when, in addition to satisfying the
requirements of C R.S. 25-15-321(3) and (5). Owner provides the following applicable showings
to the Department:

a. Restrictions on using untreated alluvial groundwater from wells located on the

property within 5i)0 feet of California Gutch for drinking, domestic, aid
agricultural purposes shall be terminated if Owner demonstrates to the State that
concentrations of the constituents listed in Table 1 of Attachment 2 in the subject
groundwater do not exceed State water quality standards For drinking, domestic,
and agricultural purposes existing at Ac lime of application. Current water quality
standards are set forth is Table 1 of Attachment 2. Any ground water sampling
conducted for purposes of terminating this Environmental Covenant shall be
conducted in accordance with Attachment 2.

h. In »ddilion to the grounds for termination set forth in Sections .3.a, the

Env ironmental Covenants shall also be terminated as to all or part of the Property
if it is demonstrated to the Department that the proposed termination will
otherwise be addressed in a manner thai will ensure protection of human health
and the environment, in accordance with C.R.S. 25-15-319(1 Xh).

Consistent with C.R.S. 25-15-321 (6), the Department shall provide to Owner a written
determination or alt applications to terminate an Environmental Covenant witlun 61) days after
receipt of such application.

4)	Mo tfi feat jam.

Consistent with C'.R S. 25-15-31 V( I )(h), the Department shall modify this Environmental
Covenant in whole or in part when, in addition to satisfying the requirements ofC.R .5. 25-1S-
321(3) and (5), Owner provides the following applicable showings to the Department;

a. Restrictions on using untreated alluvial groundwater from wells located on the
property within 500 fee* of California Gulch for drinking, domestic, or
agricultural purposes shall be modified to eliminate the restriction against one or

2

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iiitnui

159748 '.O'l/IOn 11 ,f>l AM I'itrieiii 3(h).

Consistent with C.R.S. 25 15-321(6), (he Department shall provide Owner a written
determination on all applications to modify an Environmental Covenant within 60 days after
receipt of such application.

5)	Conveyances, Within thirty days (30) alter any grant, transfer or conveyance of any
interest in any or all of the Property, the transferring Owner shall notify the Department and EPA
as the named third party beneficiary of such grant, transfer or conveyance.

6)	Notice to Lessees. Owner agrees to incorporate either in full or by reference the
restrictions of (his Covenant in my lease*, licenses, or other instruments granting a right to use

the Property.

'J-. Mo liability. The Department does not acquire any liability under State law by virtue of

accepting this Covenant,

g) Enforcement The Department and EPA as the named third party beneficiary may

enforce the terms of this Covenant pursuant to §25-15-322. C.R.S., and may file suit in district
court to enjoin actual or threatened violations of this Covenant.

9J Notice*. Any document or communication required under this Covenant shall be sent or
directed to:

Notices to the Department shall be nrovitted Jo:

[appmpriute Program Marnier or Unit leader]

Hazardous Materials and Waste Management Division
Colorado Department of Public Health ami the Environment

4300 Cherry Creek Drive South
Denver, Colorado 80246-1530

Notices to EPA shMLfesJEByMedJ"-

I-PA Remedial Project Manager

3

7-21 *' I

K-113

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Willi

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Jofs CUV RilJC.OO DSO-00	Like Countv Record

GatifomM Chick Superitaid Site

United Stales Bwvirenrnaitai Protection Agency. Region 8

(iSEPR-SR)

1 895 Wynkoop Street

Denver, CO 80202-1129

Law Department
Resurrection Mining Company
1700 Lincoln Street, Suite 3600
Denver, CO 80203

And

Director of Reclamation and Closure
Resurrection Mining Company
1700 Lincoln Street, Suite 3600
Denver, CO 8020?

E illier party may change its dtengnmed notice wciptewt upoa I days prior to n«i« to the #tm
party,

10) Property Modification. Pursuant to the Consent Decree, this Environmental Co vaunt is
intended to cover only that port wan of the Properly on which the Settling Defendants own the
entire fee title. If Resurrect >oo and the Department hereafter agree thai, as of the date of this
Environmental Covenant, the Settling Defendants did not own the entire fee title in any portion
of the property, the Pupsnrtmeml will modify Attachment 1 hereto to exclude that portion of the
Property from coverage un
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Rcsjmcction has ow*«l this instrumtnt t« be executed this. p'jtMhy of
I	V" 	.2012.

Resurrection Mining Company
By:_



Title; j/iU L'-ZJ.S.-.A X*.- Uv. .indVij

STATE OF

COUNTY OF, ClhifuJ.1^. . )

2012 b

1 be forej>om(Mristruinent was acknowledged before mc ftis^fjay of (	JeuJmr

tA\ behalf of Revurrcction Mining Company — 9V

Notary Public

Address t j i ^i^i/ [/iLtAJjA, ^

My coimnissicm«

*• mi

K-115

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,159748 IO'l,2r>l2ihHAM

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jf

Accepted py (he Colorado Department of Public Health and Environment this Q day of

— "T-

/

, y

£LL£jjl.7 C f

-2 .

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I *9748 i f.i'1i"2tH 211 ;0| AM • PMricu Inpr
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ATTACHMENT I
TO ENVIRONMENTAL COVENANT
THE PROPERTY

Mineral Survey Number	Claim Namr

1243	Conn Valley

127?	rtru Nimoiul

2MI	AlhiaiM Pteeer r«« 2

Bessie Stewart

? I?-

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359748 fn/ioun hoi am

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ATTACHMENT 2
TO ENVIRONMENT A!, COVENANT

groundwater sampi in<; protocqi.s

Aiuiytfs Wan

This attachment specifics the groundwater sampling procedures for purposes of terminating or
modifying an Environmental Covenant for groundwater use restrictions, as specified in
Appendix Fl For purposes of ihc protocol, a "property" is defined as a portion ofia claim, an
individual claim or conlipous claims not exceeding 35 acres in total area for which the
groundwater use restrictions of an aquifer arc to be terminated. The following sections describe
the groundwater sampling requirements, methods, sample analysis, and quality assurance that
will support such termination or modification. Alternate groundwater sampling procedures and
analysis methods for a property may be proposed in a sitc-spcciftc sampling plan for the
property, subject to approval by the State.

LI Groundwater Sampling Requirements

One groundwater sample will be1 collected from a well completed in the aquifer of. the
hyctfogcologic unit (alluvial. unconsolidated sedimentary deposits, or bedrock) proposed for
beneficial use underlying each property. Fur alluvial or unconsolidated sedimentary deposits, Ihc
h ydrogeo logic unit is defined a* the aquifer with the same lithology and within the same surface
water hydro logic divide The bedrock hydro geologic unit is defined as the aquifer within the
same geologic formation and stmcturc The groundwater use restrictions will he terminated or
modified for a property for only that aquifer ofi the hydrologic unit in which the Well is
completed.

The groundwater sample from the well will be analyzed for constituents that arc relevant to the
California Gulch Superfimd Site for which numeric groundwater quality standards have ten
established by ihc State for the proposed beneficial use at the time of! the application for
termination or modification of the Environment*] Covenant, .hereafter referred to .as the Numeric
Standards The constituents that arc relevant to the California Gulch Supcrfimd Site and the
current Numeric Standards are presented in Table I for drinking/domestic or agricultural uses.
The groundwater in the aquifer will be determined acceptable for the proposed use, arid the
Environmental Covenant restricting groundwater will be terminated for the property or modified
to allow a particular beneficial use, if the constituent concentrations of the sample from the well
*re less than the Numeric Standards for all beneficial uses (in the event of icrniinaimn) or the
particular beneficial use fin the event of modification).

1,1 Groundwater Sampling Methods

The groundwater sample from the well will be collected according to the methods described in
SOP No. 4-Grouixl Water Well Sampling. Non-dedicated or non-disposable sampling
equipment will be decontaminated prior to collection of the .sample according to the method*
described in SOP Mo. I-Decontamination. Sample collection documentation, sample

8

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359741 imam 1101 AM " Pmma taw

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containment, preservation, identification, labeling and shipping will be performed according to
(he procedures described in SOP No. ?- Sample Handling, Documentation. and Analysis.

1J Laboratory Analytical Methods

Samples will be analyzed for the parameters for which Numeric StimUrrf* have been estahliidherf
for the proposed beneficial use. Sample container, preservalion, and ho (ding limes arc provided
in SOP No. 7-Ssinplc Handling, Documentation, and Analysis. The laboratory will be required
to process all samples submitted according to the specific protocols for sample custody, holding
limes, analysis, reporting ami associated laboratory quality assurance, .Laboratory quality
avsurantc checks will include ihc use of Wank, spiked, split, and duplicate samples, calibration
checkv and internal standards, Designated laboratory personnel will be required to ensure that
QA/QC procedures aire achieved. The laboratory or laboratories for constituent analysis must be
accredited by she Colorado Certification Program. Laboratory calculations and data review mil!
be performed by the laboratory in accordance with the procedures described by the analytical
method. The laboratory will review the results of the laboratory QC analyses,, instminent
calibration and maintenance records, calculations, and the record of sample custody (including
hold in* times) within the laboratory

Table I	Groundwater Standards for Beneficial Use

Parameter

Domestic Water

Supply and
Drinking Water
Standards

Agricultural
Standards

Antimony-dissolved

L0O6 mgi'L



Alumm urn -tli ssol v ed



5 mg' L

• Arsenic-dissolved

0.01 tng>''L

0.1 rn&'L

i Barium dissolved

2.0 thr/H,



i BervlHttm-dis-jolved

0.004 mg/L

0.1 mft'l.

Cadmium-dissolved I O.MS ing/L

0 01 mgl-

Chloride-dissolved ^ 250 mft'L



t ed

0 1 tttft'L

0.1 mg/L

Copper-dissolved

1.0 oWL

0.2 mg/L

Fluoride dissolved

4 ttrng L

2 mjt'L

Iron-dissolved

0J mg/L

5 mji' L

Lead-dissolved

0.05 mg/L

0.1 mg/'L

Manxes:-dissolved

0.05 mtt/L

0.2 TOg't.

Mercury-dissolved

0.002 mg/'L

0,01 mg/L

Malybdtaium-di ssol ved

0,033 mg/L



Nickel-dissolved

0,1 rag'L

0.2 mg/L

Selenium-dissolved

I) 05 mg/L

0.02 in*/L

Silver-dissolved

0.05 iWR/1.



Sulfate-dissoivcd

:-v.' i



Thallium-dissolved

0.002 mg/L



Zinc-dissolved

5 rag'L

2 Mid,,

9

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SOP-1

SO!' Pofc; February 2068

DECONTAMINATION

1.0	I INTRODUCTION AND TYPfcS OF CONTAMINATION

The purpose of this dix.-um«snt is to define the standard procedure For decontamination associated

with environmental investigation for the California Gulch Supcrfimd Site, This procedure is
intended to be used wilti other SOPs,

1.1	Site and/or Sample Cross-Contamination

The overall objective of multimedia sampling programs is to obtain samples which accurately
depict the chemical, physical, and/or biological conditions at the sampling site. Extraneous
contaminant materials can he brought unto ihc sampling location and/or introduced into the
medium of interest during Ac sampling program (e.g., hy contacting water with equipment
previously contaminated at another sampling site). Trace quantities of these contaminant
materials got thus be captured in a sample and lead to fahc positive analytical results and,
ultimately, to an incorrect assessment of the eon t ami nan I conditions associated with the site.
Decontamination of non-dedicated or non-disposable sampling equipment (e.g., bailers, pumps,
and tubing) and field support equipment (e.g., drill rigs, vehicles) is required. To ensure that
sampling cross-contamination is prevented, and that on site contaminants are not carried off site.

2.0	PKOCtDl'RES

2.1	Equipment List

The following i* a list of equipment that may be unfed to perfcmi itmrnmimAm:

Brashes
Wash tubs
Buckets
Scrapers

Steam cleaner or high-pressure washer
Paper towels

Alconnx detergent (or equivalent)

Potable water

Dcionizcrf or distilled water
Garden type water sprayers
Clean plastic wheeling amd/or trash bags

2 J Decontamination

11

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2.2.1 Sampling Eijoiptnenl

The following steps will be used to decontaminate nan-dedicated or non-disposable sampling
equipment (including reusable filter apparatus):

Personnel will dress in suitable safety equipment to reduce personal exposure (e.g., latex

gloves, safety glasses, etc.).

Gross contamination on equipment will be scraped off at the sampling or t-'yostruction site.
Equipment that will not be damaged by water will be washed with an Aloonox solution or
low-sudsing detergent and potable water and sembbed with a bristle bmsh or similar
utensil (il'posxhlc). Equipment will be triple rinsed with potable water followed by a
triple rinse with dcionized or distilled water.

Following decontamination, equipment will be placed in a dean area, on or in clean plastic
sheeting to prevent contact with contaminated soil If-the equipment is nut used immediately, the

equipment will be covered or wrapped in plastic sheeting or heavy duty trash bags to minimize
potential airborne contamination,

2.2.2	Submersible Pumps

It; non-dedicated submersible pumps are used they will be decontaminated between wdK. The
outside of the pump and hwc will be tripled rinsed with dcionized or distilled water. Dcionized
or distilled waiter will be pumped through the pomp and hose. The volume of dcionizod or
distilled water ptrropeti through will be at a minimum equal to three lime*, the volume of fluid
thai amid be contained by the pomp and liose.

2.2.3	Water Level Probes

Electric water level probes will be decontaminated by rinsing with deionized or distilIctl water or
by wiping the probe during removal with paper towels wetted with deionized or distilled water.
The water level ptwbc will be placed in a plastic bag after decontamination.

2.2.4	Sensitive Equipment

Sensitive equipment that may be damaged by water will be carefully wiped clean using ptiper
towels and detergent water or spray bottle and towel and rinsed with deionizcd or distilled water
Care will be taken lo prevent any equipment damage.

2.2.5	Drilling and Heavy Equipment

Drilling and heavy equipment will be decontaminated at a designated decontamination urea for
large equipment, The following steps will be used to decontaminate drilling Jttid1 heavy
equipment:

Personnel will dress in suitable safety equipment to reduce personal exposure (e.g., gloves,
safety glasses or splash shields, etc.).

11

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.'i ''-1'S f|t AM	Patricjn 'liryn

. f3 Pl 29 tov	Mi: nil	UkfGwnlvRrcoic

Equipment showing gross contamination or having drill cuttings caked on will be scraped off

with a flai-bladed scraper at the sampling or cortstmction site.

Equipment, such as drill rigs, augers, drill bits, and shovels will he sprayed with potable
water by a high-pressure washer. Care should be taken to adequately clean the insides of

the hollow-stem augers ami buekhoe buckets.

Following decontamination, drilling equipment will be pineal on the clean drill rig and moved to
a clean area. If the equipment is not used immediately, it should be stored in a designated clean
urn

2,2,4 Equipment Leaving the Site

Vehicles used for non-intmsivc activities shall be cleaned on an as needed basis, Constmction
equipment such as earth moving equipment. I ricks, drilling nys, back hoes, trailers, etc., will be
pressure washed at the designated decontamination area before the equipment is removed from

the site.

2.2 J Wastewater

Used wash and rtmse solutions may be discharged to the ground at the sampling site
2.2.1 Other Waste

Solid wastes such as paper towels and used filters will be scaled in plastic garbage bags and
disposed of in a sanitary landfill.

2J Documentation

Sampling personnel will be responsible for documenting the decontamination of sampling and
drilling equipment. Hie documentation will be recorded with waterproof ink in the sampler's
field notebook with consecutively numbered pages. The information entered in the field bot»k
concerning decontamination should include the following:

DectmUaninntuHt personnel

Dale

Decontamination observations

13

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J5974H ia.i,ai:: ii oi am
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Lake CnuWy RteafOef

SOP-4

SOP Dam: Fnhmary 290.*

GROUNDWATER WELL SAMPLING

1,# PURPOSE AND SCOPE

He purpose of this document is to define (he standard procedure for collecting groundwater
samples from wells for the California Gulch Superfund Site. This procedure gives descriptions
of equipment, field procedures, and QA/QC pnicedurcs necessary to collect groundwater
samples from wells. The sample localisms and frequency of. collection are specified m the
QAPP.

This procedure is mit-ndcd to be used ingdber with several other SOPs, as applicable, including:
SOP I Desortsmmaticm

SOP 7 Sample Handling, Documentation, and Analysis

2.0	WATER SAMPLING PROCEDURES

2.1	Equipment List

Sample bottles, preservatives, sample labels will be obtained from the analytical laboratory
Several extra sample bottles will be obtained in case of breakage or other problems Sample
bottles can be either pre-pre^erved or preservatives can be added In die field.

Equipment that may be used during well evacuation;

Wdl keys

Elcctrunie wafer level probe

Assorted tools (knife, screwdriver, etc.)

PVC, Teflon, or stainless-steel bailer (bottom filling)

PVC hand pump

Nylon orpolypropolcne rope

Boiler tripod

PVC pump discharge ho*c

r.as-powcred electric generator

Stamlcsvstccl submersible pump

pH meter (with automatic temperature oompensjiiKJn}

Specific conductivity meter

Plastic squeeze bottle filled with deiomzed water

Polyethylene or glass container (for field parameter measurements)

Chemical-free paper towels or Kim wipes

14

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359748 ifti<201: i s oj am

. 5 of » rov R$ 152 x\ :m IX'

Calculator
Field notebook
Wateiprwfipen

Plastic sheeting {for placing around well)
Appropriate health and safety equipment

Equipment thai may be used during well sampling:

Electronic water level measurement probe

PVC, Teflon, or stainless-steel bailers (bottom filling)

Stainless-steel submersible pump

PVC pump discharge hose

hlcctrsc generator

Nylon »w pulypropolcnc rope or twine
Bailer tripod

pH meter {with automatic temperature compensation)
Specific c<»nduttivity met®

Plastic squeeze bottle filled with ocdure>

This section gives the stcp-by-stcp procedures for collecting samples in the field. Observations
made during sample col lea ton should be recorded in the field notebook and field data sheet as
specified in Section 2.4 of this SOP.

2.1.1 Decontaminate Equipment



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3S9748	1U.'1/21112 II 01 AM	PwnciftBeraer

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Evacuate three volume* of water in casing with a bailer or pomp, lake temperature, specific
conductance, and pH measurement* after evacuation of each welt volume to confirm thai
the water chemistry has stabilised Generally, pH values within -K>2 pH unit and
conductivity and icmperBlwrc readings within a.10 percent between consecutive readings
indicate good stability of the water chemistry. If the chemistry is not stable, continue
purging up to a maximum of five well volumes, measuring pH and specific conductance
after each otic half well volume.

When evacuating a well using a pump, the pump intake should be placed:

for low recovery wells (wdls. that can he pumped dry), place pump intake at bottom of
screened interval.

for high recovery wells (little drawdown with pumping), place pump at or slightly
above the midlife of tie screened interval to ensure the removal of stagnant water from

(be well bore.

If the well is bailed or pumped dry during evacuation, if can be assumed that the purpose of
removing 3 well volumes of water has been accomplished, that is, removing alt stagnant
water that had prolonged contact with the well casing or air. If recovery is very slow,
samples may be obtained as soon as sufficient water is available.

2*2.4 Obtain Water Samples

Obtain samples for chemical analysis within 2 hours after purging is completed, if possible. For
slow recovering wells, the sample shall be collected immediately after a sufficient volume is
available {water has recovered to screened interval). Ihe water quality samples idull be taken
from within the well screen interval

The following sampling procedure is to be used al each well:

1.	Assemble decontaminated sampling eijuiptneni. If bailees arc used, new nylon or
polypropylene rope will he used for each well for each sampling event. Assemble
the filtering apparatus.

2.	Make sure that sample labels have beat filled out for each well.

.1. Lower the ha tier slowly and gently into contact with the water in the well. Lower
the bailer to (lie same depth in the well each time, within the screened interval.
Retrieve Ihe bailer smoothly and empty the water in a slow steady stream into ihe
containers. If submersible or bladder pumps are utilized to collect samples, start
the pump and fill the sample bottles as described below.

4. Triple rinse the ample containers with sample water and then fill tic sample
bottles. If riot enough sample water is available to perform Ac triple rinse, then at
a minimum a single rinse will be performed and will be recorded in the field
logbook and or data sheet. Cap the sample containers quickly If sample bottles
are pre-preserved, fill the sample bottles without rinsing. Add preservative if the
bottle is nut pre-presctved. Po not allow the sample containers with pieservativcs
to overflow, See Section 2,2.5 for details on field filtering

If

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-------
IllMlli!

359748 1 «>'\.VA2 llttf AM	Pancia ft-rwr

COV Ri 1 '¦» •'*'> ™	Ukr CuUWf^c«rikr

5.	Slowly pour an un filtered portion into the sample contains- for field parameter
{pH, specific conductance, temperature, ami turbidity) analyses atwJ perform the
in-field analyses and record.

6.	Place simples on ice in a cooler.

7.	Record time oti >,arrtpling.

8.	Replace aid lock well cap,

9.	Complete field documentation.

2.2.5 Filtering Samples

Samples for metals analyses will be filtered during the field sampling event by using a
disposable filler apparatus and peristaltic or hand vacuum pump.

The following procedure is to be used for filtering:

Assemble filter device according to manufacturer's instructions.

Prior to the collection of aliquots, flush the filter with approximately 100 to 200
milliliters of.groundwater, filler sample either by puuring sample in the inp portion ofi
fillet unit or pumping through an in line filter wing a peristaltic pump Sample ro«y also
be filtered by attaching the in-line filter to the submersible pump discharge.

Triple raise the sample containers with filtered sample wate? and then fill the sample
bailies. If wt enough sample water is available to perform the triple rinse, then al a
miromum a single raise will be performed and will he recorded in the field logbook
and'or data sheet. Cap thr sample curttainert quickly If sample bottle* are pre-
prescrvcd, fill the sample bottles without rinsing. Add preservative ifithc bottie in mtf
pre-preserved Do not allow the sample containers with preservatives to overflow.

Place the used filter membrane or disposable filter equipment in a /iploc* bag for
disposal with itie personal protect!v* equipment

Any reusable filtering equipment will be decontaminated in accordance with SOP Mo, I,

2J Sample Handling

Sampie containers awl preservatives are specified in SOP Mo. 7, Sample Handling.
Documentation and Analysis. Samples will be labeled and handled as described in SOP No, 7,

2,4 Documentation

1,4.1 Groundwater Data Sheet

A ground water data sheet for groundwater samples (Appendix AJ will be completed at each
sampling location. The data sheet will be completely filled in. Ifiitems on the sheet do not apply

18

K-128

-------
iWinuiiiit

.,. . „ HW»t 2 ! 1:0t AM Fitrfdt Bejpf
J9o|» COV ISfSXii BOCift	Ij&« Couwylkenrtler

to a specific location, the item will be labeled as not applicable (NA). The informarion on the
data ihwl includes (he following;

Well number

Date and lime of sampling

Person performing sampling

Depth (o water before sampling

Volume of water evacuated before sampling

Conductivity, temperature, and pH during evacuation (note number of well volumes}

Time samples are obtained

Number of samples taken

Sample ideniifiealiitji numherfs)

Preservation of samples

QC samples t«kcn (if any)

How the samples were collected (i.e., toiler, pump, tic.)

1A2 Field Nolo

Field notes shall he kept in a bound field hook. "Hie following information will be recorded
using waterproof ink:

Names of personnel

Weather conditions

Dale and time of sampling

Location and well number

Condition of the well

Decontamination information

Tniiial static water level and total well depth

Calculations {e.g., calculation of evacuated volume)

Calibration information

Sample methods, or reference to the appropriate SOP
2.4J Weil Volume Calculations

The following equation shall be used to calculate (lie volume of water to be removed during well
evacuaaoe.

For 2 inch well:

Evacuation Volume [gal] " (Total Depth [flj - Wtier Level

Depth 1 ft]) x 0.1632 gal/fl

gallons/well easing volume

For 4-inch well;

Evacuation Volume [gal] - {Total Depth [fl] - Water Level

19

K-129

-------
For 6-inch well:
Evacuation Volume {galJ

mini I'lii

355748 1 tvtCol2 ] i oi AM	pamcia B
-------
1' VI • :«J r I 11,1H am	Patnaa 3en«f

rtrf C.tiV RJI<;o.i njtnvs	Uike Corny Rccorin

APPENDIX a
GROI NDrtVATER DATA SHEET

21

K-131

-------
g>E>riFic

Local

A3JQ&

«0-	

359748 sn.1.'20i; 11^1 am
22o»» €°V BS)5:r>-) BSCujj)

C.ROINDWAIt.R DAT A SHEET

, 		 __ Dale	 Tmr

I



Sample Control Mtumbcr_

Samplers.

Ambient An 1'crapcnmifc		'C O	°FD Ni« Mrammf - O

PrrcipiUtton None O R*it> O Snow Q Heavy D Modem* Q Light O Suiuty ~ Pitrtly Cloudy ~
WELL MEASUREMENTS fMfafmrenxrwm ir«rfr frpm ton of PVC cjcmml

Depth to Suae Watcr._

fm Trtat Dtp! of Well._

. feci It et of *»tcr_

;-jnrll - ti 163 gal? ft 4-i.nrfc» fl.6S gal/B - 1.47

1 Casing Volume			gallons	3 Casing Volumes.

Dfptfe Pt»mp lnstallcd'_ 	Hxi Vyluroc w^ic? purged			

WHI purged witfa.

HLLD PARAMETER MKASUKk VU.N fj UIHINC CUKCIM.'

	E»!k»."i

CiaJkiiM

Time

Viiluutr

(gall«s)

1*

Caod

{pS'tomJ

(crop *

TO
*»'¦~

Turbttfitv

{visual*

CMiirwh' 1

tommam























































































































































I















Sample

Date

SUBpW

Time

Volume
ijplkreO

pH

Cund

(pS'tin)

I'tmp
TQ'FD

Turiitty 
-------
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Was u riwafc Muryk colieclat-'	Ye* D Mo ~ (sample control nundiei

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Wtflw: 			 			

#

?.)

K-133

-------
lll.llllltlil 111

iaw cov sss ssr eessjs—

SOP-7

SO/1 Dfitfe. f-izbruary 20OS

SAMPLE HANDLING, DOCUMENTATION, AND ANALYSIS

1,0 PURPOSE AND SCOPE

The purpose of this document is to define fhc standard protocols for sample handling,
documentation, and analysis for the California tlulch Superfimd Site, Thii procedure is
intended to be used together with other SOPs and is referenced in all SOFs that apply to

sampling,

2.0	PROCEDURES FOR SAMF1.E HANOI.INCi. DOCUMENTATIUJM, AND ANALY'SIS

2.1	Sample Identification and Labeling

Samples col levied during monitoring, investigations. Or remediation activities will be assigned
unique sample identification numbers. Each simple identification number will ideality the
organization collecting the sample or the pro gram under which it is collected, sampling location,
type of. .sample, and sampling sequence for each sample. These numbers arc required for
tracking the handling, analysis, and verification or validation status of all samples collected
during monitoring. In addition, the sample identification numbers will be input into the project
database to identify analytical results received from the laboratory.

Sample identification number* that are aligned will be divided into Four fields as *bo*rt> in the

following example;

M-CGW1 -01 -900423

The first field is irnc character in length and identifies the company wmstlutting the >uinpliog.
The second field is an alphanumeric code identifying the location ofthe sample and the list letter

ofithK field indicates the matrix. (e.g., CGM1 indicates California Gulch Well No. t, the second
W indicates a water matrix). The neat field identified is she type c»f sample being collected; this
is used to identify whether the sample is a primnry or grab sample, * cornpttxile sample, field
duplicate, field blank, or equipment rinsate. The final field contains (he date in « ycar-month-day
format, for example, the sample identified Above was collected on April 23, 1990

Each sample that is tolled.ad in the field will be lubclud for future identification. Sample labels
will be filled out as completely as possible by a member of the sampling team pri»r t« the a art est!
the day's field sampling activities. The date, time, sampler's signature, and the last field of the
sample identification number should not be completed until the sample is actually collected. All
sample labels will be filled out using waterproof ink. Al a minimum, each label will contain the
following information:

24

K-134

-------
389748 IWlfiOP I l;OS AM	P*r.c, tkigfr

?.5er?.9 COV RS1S2.00 D50-TO	Uk*C;iMyk««*kr

Sampler's company nfTilialicrn;

Site location;

Simple identification;

Date and time of sample collection;

Method of preservation used;

Sample msfn*; and

Sampler's initials.

1.2	Sample Containers, Preservatives, and Holding Times

2.2.1	Sample Containers

Proper sample preparation practices will be observed to minimize sample contamination, and
potential repeat analyses due to anomalous analytical results. Prior to sampling, cc,«rnma*dalJy-
cleaoed sample containers will be obtained from the analytical laboratory. 'Ihe botrles will he

labeled #s described in the previous section to indicate the type of sample and sample matrix to
be collected, Sample bottles can he either pre-pre«erv«l from the laboratory or preservatives can
be added in the field during sample collection,

2.1.2	Sample Preservation

Samples ate preserved in order to prevent or minimize chemical changes that could occur during
transit and storage. Sample preservation should be performed immediately upon sample
collection to ensure that laboratory results are not compromised by improper coordination of
preservation requirements and holding Times. Samples wilt be preserved immediately and stored
on ice in coolers prior to shipping. Sample preservation requirements are based on the most
current publication of40C'FR, Part 136.3 and. are provided in Table 1.

2-2 J Sample Holding Times and Analyses.

Sample holding times are established to minimize chemical changes in a sample prior to analysis
and/or extraction. A holding time is defined as the maximum allowable time between sample
collection «imt) analysis ami/or extraction, based on ihc nature of the arudyte of interest and
chemical stability factors. Holding times applicable for analylcs are listed in Tabic 1, Samples
should be sent to the laboratory as soon as possible after collection by hand delivery or an
overnight courier service to minimize the possibility of exceeding holding times.

For most samples., preservation by coating to 4"C is required immediately alter collection while
the samples are hdd for shipment aid during shipment to the laboratory,

2.3	Sample Preparation and Shipping

After collection, samples will be labeled and prepared w described in Hie previous discussion,
and placed on ice in an insulated cooler. The sample containers will be placed in re-closeabie
plastic storage bags. Samples will then be placed right side up in a cooler with ice for delivery to
the laboratory. The ice in the cooler will be double-bagged. The coolers will be taped shut and



K-135

-------
Iff f cnv SffL2

«.€» »1. *5 COV R$15i,W BSftCKi	Lake Couttv-ftccndcr

cham-<>f custody seals will he attached lu the outside of the cooler to ensure thai the coder
cannot be opened without breaking (he seal. Final packaging and shipping will be conducted in
compliance with cunenl 1ATA Resolution 618 and DOT 49 CFR Pat S7l Regulations,

All samples will be shipped for laboratory receipt and analysis within the holding lime* specified
in Table 2, This may require daily shipment of samples with short holding times,

2.4 Sample Documentation and Tracking

This section describes the information that should be ptwi&si in IsM «Xc$ and sample Chain
of •Custody docinximtimoB.

2.4.1	Field Notes

Documentation of observations and data acquired in the field provide infnnnjitjon oft sample

acquisition, field conditions M the time of sampling, afid a permanent record of field activities,
Field observations and data collected during routine monitoring activities will be recorded with
waterproof ink in 8 permanently bs'und weatherproof field log book with consecutively
number at pages or on field data sheets as specified in the piwject SO FN

Field notebook and'or data sheet entries will, ai a minimum, include the information listed
below. Relevant SOPs should be consulted lo supplement this list.

Project name;

Location of sample;

Data and time of sample collection;

Sample identification numbers;

Description of sample (matri* sampled);

Sample depth (if applicable);

Sample methods, or reference to the appropriate SOP,

field observations;

Results of any field mensuranents, such as depth to water, pH, temperature, specific
conductance; said
Personnel present.

Changes ur deletions in the field book or on the data sheds should be recorded with a single
strike mark, arid remain legible. Sufficient information should be recotded to allow the sampling
event to be reconstmeted without having to rely on the collector's memory-

All field books will be signed on a daily basis by the person who las made the entries. Anyone
making entries in another person's field b«»k wiil sign and dale those entries.

2.4.2	Sample Cbain-Of-Custody

During field sampling activities, traceabtlitv of the sample must be maintained from the rime the
samples are collected until laboratory data arc issued. Establishment of traceabiiity of data is

26

K-136

-------
.159748 Iftl'Jfli: I! 151 AM	Pnyia&Befjcr

:?uf>9 an' n$mm tm.m	i*tc<*mK*tix4»

cmrial for resolving future problems if analytical results arc tailed into question and for
minimizing the possibility of* sample mix-up, Initial ittfimnation concerning collection of the
samples will be recorded in the field log book or on data sheds as described above. Information
on the custody, transfer, handling and shipping of samples will Ik recorded on a Cham-of*
Custody (COC) form.

The sampler is responsible for initialing and filling out the COC form. The COC will be signed
by the sampler when he or she relinquishes the simples to anyone else. A COC form will be
completed for each set of water quality samples collected, «od will contain the following
information:

Sampler's signature and affiliation

Project number

Date and time of collection

Sample identification number

Sample type

Analyses requested

M Limber of containers

Signature of persons relinquishing custody, dates, and times
Signature of persons accepting custody, dates, and times
Method of shipment

Shipping air bill number (if tht samples are shipped)
Any additional mstmctions to the laboratory.

The person responsible for delivery of the samples to the laboratory will sign the COC form,
retain the third copy of. the form, ducurnent the method of shipment, and send the original and

the second copy of the form with the samples. Upon arrival at the laboratory, the person
receiving the samples will sign the COC form and return (he second copy to She Project
Manager. Copses of all COC documL-ntatiun will be compiled and maintained in the central files.
The original COC forms will remain with the samples until the time of final disposition. After
returning samples for disposal, (he laboratory will send a copy of the original COC to the
Operator. Hiis will then be incorporated into the central flics.

«

27

K-137

-------
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K-138

-------
RECTION MINING COMPANY ENVIRONMENTAL COVENANT "C" ZONE PROPERTIES

K-139

-------
Figure K-10: Lake County Building Permit Procedures

Lake County Building Department

Li;ulvilk\ t tfloriulu 8((46i

Tv-icpt)>»iK t 719) 4Xfi*2S75 - Fax (71") 4Siv4179

Step by Step Procedures to Apply for a Building Permit
Applicable on all construction:

1	Copy of deed.

2	Copy of Assessors account number and map (located in the
Assessor's office.)

3	Building Permit Application along with three sets of plans (one
set can be in a PDF form) and three site pians (one can be in a
PDF). Your plans should have the Type of Construction. Use
and Occupancy and the Maximum Occupancy.

4	Building Permit Approval Form with aM Agency signatures.

5. Plan Check List must be completed and signed.

3943780^6 Payment of Building Permit Fee. This will be

calculated in our office. Checks payable to: Lake County
Treasurer.

Other required submission material:

1.	Applicant is required to getting a septic permit from the Lake County
Health Department (Jackie Littiepage 719-486-7481)

2.	Approved Well Permit from the State of Colorado- or where the
project is located in a platted subdivision with an approved water
supply plan, or on a 35 acre parcel or larger, then a Well Permit
Application may be submitted in lieu of the permit an approved well
permit from the State of Colorado must be submitted prior to the
issuance of the Certificate of Occupancy,

3	Signed acknowledgment that you have received the California Gulch
Superfund Site Operable Units 2, 3, 8. 9, 5. 4, and 7 best management
practices handout, if you are building in these areas. {Please see map
in Building Department.)

4	Letter of approval from the Colorado Department of Public Health and
Environment to build Operable Units 2, 3 8, 9. 4, 5 and 7 of the
California Gulch Superfund site, if required.

'Bull$ftg\Me*20l2 Buittng permit apsrftestfcaasoc

-1 -

K-140

-------
AH of these requirements MUST BE SUBMITTED or we cannot

accept your application.

LAKE COZw\7T

nvn.niMi im/tinovproceiwhm. isformano's

(Please Metal!!)

Lake County Iw adopted cotwiruclltMi regulations »»d permitting requirements to help assure thai strncliifts
meet certain minimum standards for safeguarding the occupants, property and the public welfare.

Permit Require!

Regulations require a building permit to concuci the following activities

•	New building construction

•	Additions and alterations to existing structures

•	Structural repairs to existing buildings

•	Relocation of existing buildings

•	Change in use or occupancy of existing buildings

•	Abatement of unsafe ouildmgs or structures

In addition to the Building Permit, some projects may also requite an electrical permit,
plumbing permit or a mechanical permit. If applicable, a separate electrical permit is required
for the installation of a well.

All projects located within the California Gulch Superfutid Site Operable Units 2, 3, 8, 9, 4, 5
and 7 may have additional requirements such as approval by the Colorado Department of
Public Health and Environment. To build on such properties, the applicant must;

1. Check the California Gulch Super-fund Site map in the Lake County Build ng and Lard Use

Department to see if the project Site is in either Operable Unit 2, 3 8, 9, 4. 5. and 7, If riot,
proceed with stand a'd building permit process,

2 If so then review Resolution 2005-06 and ootain tne Best Management Practices handout

3, If required provide letter of approval from the Colorado Department of Public Health and
Environment, along with all olh« required submissions for a Building Permit

4 Sign the Late County Building Department Affidavit

These are all separate permits and are not included in the Building Permit.

Work Exempt

Lists of common projects that do not require a building permit are:

•	One story detached accessory buildings used as a tool or storage shed, or for similar
purposes, which do no: exceed 200 square feet

•	Fences not over 8 feet high,

•	Retailing walls not over 4 feet from top to botrom and do not support a surcharge.

!•.» \S,'oit'itiuiitT>__Mc	All :l>* y^'-kv/ 20 1 £ bu-hl -y -in! A:;.) l-yti \:'a

K-141

-------
*	Painting, papering, and simitar work,

•	Barns and storage buildings used for agricultural purposes only.

Unless specifically authorized, no construction work may be performed on your project (intil a
Buiidinq Permit has been issued. Ptojects commenced without proper author iration are
subject to a penalty equal to the base permit fee. Additionally, circumstances may require you
to remove part or all of your project up to that point.

Manufactured housing (mobile homes) placed m <1 mobile home park do require a building
permit, an eloctrtcal permit for electrical service, a plumbing permit for water and sewer and a
mechanical permit for gas service is required.

Lake County has adopted the following codes:

•	international Building Code, 2012 Edition

•	International Residential Code, 2012 Edition, including Appendices E and G

•	international Mechanical Code. 2012 Edition

•	International Plumbing Code. 2012 Edition

•	International Fuel Gas Code, 2012 Edition

•	International Existing Building Code. 2012 Edition
»	Nat ion a I Electric Code 2012 Edition

•	International Fire Code. 2012 Edition, including Appendices B. C. D. and F

•	International Energy Conservation Code, 2006 edit,on

Code Amendments and Design Information

Wind ana Seismic

¦	Basic Wind Speed =¦ 80 mph

¦	Seismic Zone = C

•	Wall reirforcirg must meet the minimum requirements specifiec in the 2012 IRC with the
exception of private dwellings and related structures. Tney may use #4 bar @ 24" horizontally
and vertically for 8' walls

•	Concrete footings shall be a minimum of 8 inches thick and 18 inches wide with too #4 bars
continuous, {On overlapping points, a 2' minimum is required),

•	Bottom of footings shall be placed a minimum of 4 feet oelow finished grade.

•	Foundation for single story garages and lesser structures shall fee evaluated on a case by
case basis

Soils

Soils tests, are not normally required for dwellings and related construction, although such work nay
be required when circumstances warrant or when, required by a recorded final plat for a subdivision.
Commercial and industrial structures of significance require a soil report as part of the submittal for a
building permit

t \i WUKi* low '1a' • :j p:/ '(lit vr-\iir;U!'

K-142

-------
Ctw/tf Balls

Open guaidrg^s shall have intermediate rails or an ornamental pattern with spacing less than the
diameter of a 6 inch sphere, except in industrial and com me real locations not open to the public.

Design Criteria

All design criteria used for the structure must be clearly stated or? the plans. Please include snow
loads. Boor load's ami soil beating capacity

•	Plans found to be lacking in design or detail will be rejected, causing your plans to
lose their place in the order of review. Submitting a clear, well detailed set of plans
will help ensure your permit is issued in a timely fashion. Good planning also helps

to prevent costly mistakes in the field,

•	Payment of the Building Permit Fees must be made at the time of submittal. The tees
will be calculated at the time of permit application.

•	If you disagree with any orders, decisions or determinations made by the Building
Official relative to the application and interpretation of the codes, yuu have the right
to appeal such decisions to the "'Lake County Building Code Board of Review."
Information on this process may he obtained upon request,

Permits

Separate permits are required for each separate structure. Separate permits are also required for
separate types of wo'k suc-h as building, plumbing, mechanical, and electrical. The Builstasi Permit
authorizes the construction af the foundation system, framing, sheathing and related finish work for
the overall building or structure and its attachments such as parches and decks.

Application Form

•	Provide all requested information on the application form. This information is needed in
order to process your application, so. please write legibly.

•	All construction sites must have a physics5 address. If the project does not have an address
or you do no! know it. contact the Land Use Planner to have one assigned The name of a
mining claim or a lot number is not an a caress. If you need to have an address assigned,
include on your site plsn the name of the property owner, teg a I description of the lot,
property lines, easements, named roads, any existing or proposed structures including
buildings, well, septic tank, and leach field

•	A setback distance is the closest perpendicular distance from the property line to the
footprint of the structure Attachments such as porches or a carport must be considered in
determining the setback distance. Certain types of work such as, new construction,
alterations to the exterior of a building, or changes »n occupancy cannot be reviewed without
this information. These distances should be d scussed with the Land Use Planner prior to
the planning process, as they can place limits and/or additional requirements on the project.

•	The owner or his representative must sign and oate the form.

!> '.Uyit-tmiiiCv S4- "ire-v't fititiiiuif'y vu.<¦*--«'"- -j p;_>,-'lit :-m-atort »:u"_

-4-

K-143

-------
Approval Form

•	Your project may -equue approval from a number of different agencies. The Approval Farm
provides a checklist for the entities usually involved A member of the Building Department
will be happy to aid you in identifying which approvals you wtl need for your particular
project,

•	Some subdivisions reqj.re approval from their architectural review committees before
commencing any construction projects. Make sure the plans you submit have oeen
reviewed arid approved by the subdivision's review committee Having to submit new plans
to I he Building Department cou>d result in added cost for additional rev ew time

•	In some cases agencies other than those listed may be involved, such as the Amy Corps
of Engineers, U S Forest Service or the Colorado Department of Public Health and
Environment. Provide copies of any permits or tellers of approval from any of these
agencies. For individual we is, you must provide a copy of the well permit or permit
application where allowed. Wafer supply by any means other than these listed will have to
be explained in detail and submitted for approval as an alternate 'means of supply

•	All pertinent approvals by other agencies -mist oe obtained prior to suomitting plans for
review

Approved Plans & Inspection Card

The sets of approved pians that you receive back are the plans you must use for your
construction They must be kept at the construction site al all times The inspection card and
Building Permit will be contained In 3 plastic permit holder to protect them The plastic permit
hoioer must be posted in an obvious, location on the construction site and in such a manner as
to give the inspector ready access to it, Copies of any other permits that your project requires
should be kept in the permit holder, as well. After each inspection, the inspector will leave
copies of each field inspection report inside (he permit holde*. in addition, the project address
MUST be posted and clearly visible from the roadway.

V 'S-oit imnir>_!M' >m: >»»K	i s'Jii -l>* yV l>v, A11J t.u« I¦ y ,:i' "ill -'h «l!»ti va

K-144

-------
Lake County Building and Land Use Department

B-nkii'-fj I «<¦!•: -I v- Fiivniiiitfc,,'l-il hi-.1 tit	*!*?<,*•*—n mic.

I I i-vMmri ; I ns • 11 aj >vn I *- .aim i ¦ i 'M> i -i; ujt, i| I iv- h. r| ,

H	Fshl IJ $1	^ m -PH

L y • ¦ t Fsitf i] 42	.0 BOO fret

v ert?nni;il! leg^t:-	!J,- U-J rozt

3 dv*' Ti j i;t	'? .C 0 -"5 ""e-I

c-b *^1! Lctcitcc	U bUJ "c:t

-ini" Ot-din mo fret

..'C'-" Vailcv ~i rcjo^I i *2 'U U-jO feet

.i.i: li II Ai I^i.

9,4riC> 'f-l

3'¦~¦"id West P'oioitic:

b .'JO J "crt

'•:clj|.c I'Dbt Club

iO 3JO feet

V1

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M: Mac cm? ~0JlCljt

0,503 "e£t

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u i.orrriu _cf ccjucr.Tiijnt' C o \ i c o ; D midtr&\e w 20'2 0uidno po'trri aoo k,mn doc

- 6-

K-145

-------
Slringtoftti	9,900 feet

Sylvan Lakes	10 300 fee:

Turquoise Lakes Estates	9,600 feet

T'.vin Lakas	9,400 feat

Twin Lakes Filings	9,800feet il-A, -B& 1-G3)

Plans Check List

Lake County Building Department

Parties submitting plans are responsible for providing all information necessary to perform a complete plan
review for Code compliance, incomplete plans will be rejected and may -racd to bo resubmitted only after all
requested information is included. Review time for all plans will be the same, whether it is a new submittal or a
le-subrrittal StMds^,5Ktiqn5.fl,ieipriffifflcsllil« pulyf

QslsM

~	~ Submittal must include three sets of plans (one of those plans can be in a PDF) with the

applicant's name arid project address on every sheet The plans shall be drawn to scale
at no less than 1/4" - 1" (except the site plan), drawing sheets shali be 24" x 36".

Your plans should show they type of construction, the use and occupancy and the
maximum occupancy.

~	~ Loads and material strengths used to design the structure are included (Snow load(s),

actual or assumed soil bearing capacity, concrete strength, type and grade of wood
members, type and strength of laminated wood members, etc.).

~	~ Any alternate details or construction methods that will not be used must be struck

through, clearly indicating it is not petmer*

I 1 U Res or a prescriptive method report has been done and printed results submitted with
plans. (This can be done by going to wvwy.energycades.gov, downloading the software
and ending the required information Prim the results]

Site Plan

~	~ Plans show property lines, easements, public access road yr street, streams, springs,

and wetlands

~	~ All site improvements, including adpeent parcels, existing and proposed are shown:

including structures, waste disposal systems, wells, and driveways.

~	~ Plan is fully dimensioned showrng property Jine lengths, perpendicular distances from

the proposed structure to the property line and distance from the well to the absorption

field.

LI U Plan includes the lot number, subdivision, address, a north arrow, adjacent street
names, landmarks arid the direction and amount that the site slopes.

~	~ Indicate the distances from the edge of the road to prooosed structure

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~ ~ A survey report to verify setbacks is required at ho me stake Subdivision at the time cf
foundation and'or footing inspection

Architectural1

BlttJfieiS

~	~ A complete floor plan is included for each ie-/el, including the basement, and rooms are

labeled as to use.

~	~ Window and door sizes are shown, emergency egress windows are noted and

tempered glass is shown where required.

~	~ Location of smote defectors, fans, gas appliance vents, plumbing fixtures (including hot

tubs, spas, or whirlpool tubs), size of furnace or boiler and water heater, are shown and
type of fuels are specified

U U Full elevatiorsi views, including foundation, are provided for all four (4) sides.

~	~ Reference the average, naturally occurring grade at the base of the structure which

exists prior to construction on all 4 views using a scale of 1 -'4 inch = 1 fool.
O ~ Foundation steps, openings anc finished grade are shown

~	~ Attic a no crawl space vents are shown

Cross Sections

~ ~	Sectional views of all aspects of the project are provided

n n	All ceiling heights and roof slopes are shown

Foundation

1	A fully dimensioned foundation plan is provided,

i 1	Location size and details are provided for all walls, footings, piers, and oads.

Z ~	Size, spacing, and grades of all reinforcing are shown,

r n	The locations of all wall openings arid foundation steps are shown,

_ 1	Any cantitevered walls are fully detailed and stairped by a licensed COLORADO
engineer

_ J	Water p'oofmo and subsurface drainage are indicated

Z ~	Survey Report required at Horre stake Subdivision to verify setbacks.

structural

~

o

I i

~

o

~

A framing plan is pro video for each floor, roof, decks, garages and porches.

Type, size and spacing of all joists, rafters and slud walls are shown.

Layout and spacing of trusses are shown, any site-built trusses are detailed and
stamped by a COLORADO licensed engineer (certified details or pre-manufactured
trusses may be submitted when received from supplier).

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o

~

All framing plans shall include the support system, with the location and size of all





beating walls, beams, headers and columns. Please note the posts and beams on





either the floor or roof framing plans.

n

n

Type and size of all doors and window headeis are shown

n

H

Lateral bracing provisions are shown.

r ¦

LJ

i;j

Type, thickness and rating of floor ana roof sheathing are shown

n

n

Major framing connections are detailed.

o

~

Width, clear height and rise and run of all stairways are shown including the location





and heights of hand and guardrail

~

~

All design toads are noted (roof, door, and decks)

Modular

Homes

DO A full foundation plan is required (See "Foundation"' requirements above)
D O Plans submitted must be stamped by a licensed Colorado Engineer or have the State of

Colorado Division of Housing slamp with date.

_ '~ Snow load must be stamped by a licensed Colorado Engineer.

Z ~ Otherwise, submit a letter from the manufacturer stating the pitch of the roof with
applicable-

snow load and the manufacturers certification that the plans meet or exceed the
requirements set forth by the State of Colorado Division of Housing for a HUD or UBC
modular home.

California Gulch Superfund Site

~ LI Evidence of approval by the Colorado Department of Public Health and Environment to
bund in Operable Units 2, 3, 8, 9 4. 5 and'or 7 of the California Gulch Superfund Site

(Owner} Checked off by	_	on __________ 2*0

(Office) Checked off by	on	20

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Lake County Building Department

P.O. Box 513«505 Harrison Avenue • Leadville, CO 30461
(719) 486-2876 * Fax (719) 486-4179

Building Permit Application and Approval Form

Office Use Only

Building Valuation $
Base Permit Fee $
Plan Review Fee $
.Building Permit Fee $

Date Received.
Permit #
Check#

Co-!ta;t information

1.}	Applicant

Mailing Address

2.)	Owner of Property

Phone

Mailing Address _

3.)	Contractor

4.)Archi	tect/En gin e er

PI ease Print All Information Legibly

Phone

Phone
Phone

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Site Information

1 ) Location of Construction' fl Lake County ~ Tw-n Lakes
39437743,2} Project Address
394376592 } Legal Description:

Section
Subdivision

Township

Range

Lot

4.) I he site is	

Operable Unit 3

Block

Filing

is not

OU 8

located within the California Gulch Supertund Site
OU 9	OU 4	OUT

OU 2

OU 5

Emmttafsmmtim
Type of Work

Li New L Addition _! Alteration (Internal or External) U Change of
Occupancy
Use of Structure

~	Single Family Dwell-ng C Private Garage	~ Private Storage Building

~	Other Private Structure
J Commercial

~	industrial

J Other

Work Description	

Previous Use (For Change of Occupancy)

Type of Construction. Use and Occupancy and Maximum Occupancy

Building information

Distance to Property line

Front Yard Setback'	Rear Yard Setback'

Side Yard Setoacks (Left Side):	(Right Side)

Street Setbacc	Area of Lot:

Total Building Height:	_Easem.ents: ______

~ Wood Frame LI Modular	~ Steel Frane ~ Masonry mother	

Number of Bedrooms:	(New): {Existing):

Number of Floors.	Nurr.oer of Bathrooms

Buililins Permit Application
I'aCt 2

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Area of Spaces (in square feel, using outside dimensions}

Unf rushed Basement.	First Floor	Second Floor

Finished Basement: 	Garage:	Carport:

Deck: _Otier
Total Area of Enclosed Spaces' 	

Utility Information

Water Supply OIndividual Weil (IPubl.c System	

Wasre Disposal System F1 Individual System ITIPublic System 			

Primary Heating System ijElectric L. Natural Gas ~ Propane DWood

~Other

I hereby certify fnat (o the best of my knowledge this application in forma I ion is correct I understand
that no work on the applied for project may be performed until authorization is given by the Building
Official and work that s authorized must be inspected at specified stages of the construction and be
approved before the work may proceed to the next stage, I further understand that requests for
inspections must be made at least 24 hours in advance

Applicant s Signature

Date

Building Permit Approval Form

ADDRESS:



Ifei.

\|ifirn> i d

©eifetf

Comments;

Wafer #>.-«>« omi)	O Call your wafer company for a locate

• We ask that you provide this signature, so that way the Building Department can confirm there
_ Parkviile Water	20*5 Poplar Street 486-1449

ri	Vtfat&r District

V>: 
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_ ini1i\kliiai Well

.'•'v/w.n-. s'tf.'f '>} p^nni) t.'i I'irTii





Date

Appiwcil

Denied





Comments:

Waste Disposal (pitas® cr^c*O Cat} your utility company for a locate

• Wi> ask that you provitie this signature, so tli.it way tho Building Department can confirm there
u Leaoville Sanitation D'strict 911 U.S. Hwy 24 486-2993
I; Lake County Public Health Jackie Littlepage 11? We si Street 713-486-7481

Sanitation District

Bale

\ p |>m\ tii

Qetmd

Communis;

Fire Safety

• We ask that you provide this signature, so that way the Building Department can confirm there
	Lead vile/Lake County Fire Depart men?	816 Harrison Avenue 486-2990	

Common rs;

Utility Services (please check one) ~ Call your utility company for a locate

* We ask that you provide this signature, so that way the Building Department cart confirm there

H XCEL Energy	Residential & Commercial - Britt Mace (970) 282-4032

Send a 11x17 site plan via email:Brittany Mace@xceieriergy.coni

	~ Sangre de Cristo Electric Association	29780 Hwy 24, Buena -1-l	. 		

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~ 3ropane or Natural Gas Supplier
U Other

I feu*

Appro* «l

Zoning (please check one)

D City of Leadvilte

n lake County Land Use

California Gulch Supeifund Site (if applicable}

Operable Unit 3 Operable Unit 9_
Operable Unit 8 Operable Unit 4,
Operable Unit 5	

800' Harrison Avenue 486-2092
505 Harrison Avenue 486-1796

Operable Unit 7
_ Operable Unit 2

Date

Approval

Denied

Comments:

Plan Review

Lake County Building Department

505 Harrison Avenue 486 2375

Tfcilr

A|i|»n»> itl

Denied

Comments;

Final Approval:	_Date:

Chief Building Official or Designee

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Lake County Building Department

Affidavit

Building Permit #:
Property Address'
Owner:

1.	Dunng the construction of t",is project, I understand that I am required to have ether a portable
toilet on site or arranges tor tho use of existing facilities. I understand that rt those arrangements
have not been made the inspector will nel perform inspections at my job site.

2,	I a-so understand that I am required to keep the construction site clean and free of construction
debns with trash containment available

i All const-action and/or work for which a permit is required shall oe subject to inspection by the
Building Official! and all such construction and'or work shall remain accessible and exposed for
inspection purposes until it nas been seen ana approved by the Building Official

4, It shall be the responsibility of tho permit applicant to csjsc the construction and/or work to
remain accessible and exposed for the required inspection!si and approvals Neither the

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K-154

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Building Official nor Lake County shall be liable for expense entailed in the removal or
replacement »' any mateiiai* inquired to allow the required wspacliorisfs)

5 I have received read and understand ths„„Be5l,,Minaa£;,ms,rttEracti«!Sr tQf Managing .cad.
Arsenic and Cadmium Containing Soils in Lake County. Colorado handojL if ry project is
located within Operable Units 2, 3. 8,9. 4, 5 and 7 of the California GulcH Superfund Site, as

applicable,

6. Tlrs building permit is valid under the tohowing conditions'

•	Sfrail become invades ot» year from dale of issuance

•	Shall become invalie if the work authorized by such oermr? is not commenced within 180

days after its issuance

•	S^all become invalid if the work authorized by this permit s suspended or abandoned for
a period of 130 days after the time the work is commenced.

•	The Building Official re authorized to grant two extensions for periods of not more than
160 days eactr at no cost to the applicant.

•	Any extensions shall be requested in writing and justifiable cause demonstrated.

•	Extension requests must be made within 10 business days of expiration of the permit

•	If the extension is not made within this time frame a payment of 50% of the base permit
fee will be required.

•	Any extensions requested above the two ISO day extensions, as stated above, will
require a payment of 50% of the base permit fee.

Signature	Date

Lake County Building Department

P.O. Box 513 • 505 Harrison Avenue - Leadviile. CO 80461
(719) 486-2875 • Fax (719» 48S-417S

Driveway Permit

(Resolutions 98-15 and 98-35)

PERMIT; To connect a driveway or parking area to a public roadway, modify an existing driveway, or
re-grade an existing driveway. fRo.aciwatf Pes ion Standards, Section 254)

PROPERTY OWNER;	 PHONE;	

LOCATION OF WORK;	

PHYSICAL ADDRESS FOR JOB SITE;

APPLICANT:

CONTRACTOR; 		 PHONE;.

MAILING ADDRESS; 		__

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K-155

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NATURE OF WORK:

STARTING DATE:

AUTHORIZED BY;

DRIVEWAY PERMIT APPLICATION PROCEDURES

Subrrit to the Lake County Building Department/Land Use Office;
1 i A completed appl'catior foim

2)	A $50.00 Tee: and

3)	two [2) copies of tne site plan

The Srto Plan must bo drawn to scale and must include:
a) The name of the property owner,
fc) The physical address of the property;

cl All property lines easements, roads, and existirg and proposed structures on the

property (including buildings, well, soptic tank arsd teach field?; and
d) The driveway location, dimensions of tie driveway, surface material, stope, culvert size,
d stance to the neighbor's driveways. and distance to intersection or curb return.

(Office Use Only)

PERMIT FEE; $50.00 CHECK #;

DATE RECEIVED;

APPROVED BY:

DATE:

INSPECTED BY:

FINAL INSPECTION DATE:

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Additional Information

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Figure K-ll: OU12 Institutional Control - Parkville Water Restriction on Private Wells in the Parkville
Water District

RULES AND REGULATIONS OF THE PARKVILLE WATER. DISTRICT
27 October 2006

ARTICLE 2 - PROHIBITIONS

K-158

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rarGviflk

Source: Parksville Water District - Lake County Maps accessed 8/15/2022 at https://www.parkvillewater.org/wp-content/uploads/2015/05/dist-map-lg.gif

K-159

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