DRAFT ENGINEERING EVALUATION/COST ANALYSIS UMPQUA ABANDONED MINE LANDS (AML) SITE DOUGLAS COUNTY, OREGON

Prepared For:

U.S. Department of the Interior Bureau of Land Management Roseburg District Office

Prepared By:

Dynamac Corporation 20440 Century Boulevard Germantown, MD 20874

Work Assignment No.: BLM3-55R Date Prepared: 30 April 2001 BLM Contract No.: 1422-N660-C98-3003

TABLE OF CONTENTS

EXECUTIVE SUMMARY ...... ES-1

1.0...... INTRODUCTION 1

2.0...... SITE CHARACTERIZATION 2 ...... 2.1 Site Description and Background 2 ...... 2.1.1 Site Location 2 ...... 2.1.2 Type of Facility and Operational Status 2 ...... 2.1.3 Structures/Topography 2 ...... 2.1.4 Geology/Soils 3 ...... 2.1.5 Hydrology 5 ...... 2.1.6 Surrounding Land Use and Populations 5 ...... 2.1.7 Sensitive Ecosystems 5 ...... 2.1.8 Cultural Resources 6 ...... 2.1.9 Meteorology 6 ...... 2.2 Site Waste Characteristics 6 ...... 2.3 Previous Investigations 7

3.0...... SOURCE, NATURE, AND EXTENT OF CONTAMINATION 8 ...... 3.1 Waste Source and Soil 8 ...... 3.1.1 Sampling 8 ...... 3.1.2 Analytical Results 9 ...... 3.1.3 Volumes 10 ...... 3.2 Surface Water and Sediment 11 ...... 3.2.1 Sampling 11 ...... 3.2.2 Analytical Results 12 ...... 3.3 Summary of Results 13

4.0...... STREAMLINED RISK ASSESSMENT 15 ...... 4.1 Human Health Risk Assessment 15 ...... 4.2 Ecological Risk Assessment 16 ...... 4.3 Uncertainty Analysis 17 ...... 4.4 Risk Assessment Results 17 ...... 4.5 Removal Action Criteria 18

5.0...... IDENTIFICATION OF REMOVAL ACTION SCOPE, GOALS, AND OBJECTIVES 19 ...... 5.1 Definition of Removal Action Objectives 19 ...... 5.2 Removal Action Schedule 19 ...... 5.3 Applicable or Relevant and Appropriate Requirements 20

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TABLE OF CONTENTS (Continued)

6.0IDENTIFICATION AND ANALYSIS OF MANAGEMENT AND TREATMENT TECHNOLOGIES 21 ...... 6.1 Introduction 21 ...... 6.2 Evaluation Criteria 21 ...... 6.3 Removal Actions Alternatives 22 ...... 6.3.1 Description of Broad Categories of Potential Removal Actions 22 6.3.2 Identification and Screening of Management and Treatment ...... Technologies 23 ...... 6.3.3 Assembly of Removal Action Alternatives 31

7.0...... COMPARATIVE ANALYSIS OF ALTERNATIVES 44

8.0...... RECOMMENDED REMOVAL ACTION ALTERNATIVE 45

REFERENCES ...... 46

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LIST OF FIGURES

Figure 2.1 Site Location Map Figure 2.2 Site Map Figure 2.3 Site Detail Map Figure 2.4 NRCS Soil Survey Map Figure 2.5 Site Soil Units Map Figure 3.1 Waste Source and Soil Sample Location Map Figure 3.2 Sample Location Map (XRF Transects) Figure 3.3 TCLP Sample Location Map Figure 3.4 Surface Water and Sediment Sample Location Map Figure 4.1 Mine Waste Conceptual Site Model for Human and Ecological Exposure Figure 6.1 Alternative 2 Plan View (Institutional Controls) Figure 6.2 Alternative 3 Plan View (Consolidate Waste Material in an On-Site Repository, Cap, and Revegetate) Figure 6.3 Cap Cross Section

LIST OF TABLES

Table 2.1 Soil Unit Properties Table 3.1 Waste Source and Soil Sampling Summary Table 3.2 Approximate Volumes of On-site Waste Units Table 3.3 Waste Source and Soil Sampling Analytical Results (Mercury) Table 3.4 Waste Source and Soil Sampling TCLP Analytical Results (Mercury) Table 3.5 XRF Analytical Results (mg/kg) Table 3.6 Waste Source Sampling Analytical Results (TPH-DRO) Table 3.7 Surface Water and Sediment Sampling Summary Table 3.8 1999 General Water Quality Parameters Field Measurements Table 3.9 Surface Water Results, Regulatory and Risk Based Thresholds for Mercury in Water Table 3.10 Surface Water Sampling Analytical Results (General Water Quality Parameters) Table 3.11 Sediment Sampling Analytical Results Table 4.1 Umpqua Mine Comparison of Analytical Results and Risk Management Criteria Mine Waste Results (mg/kg or ppm) and Surface Water (ng/l) Table 5.1 Summary of Potential Chemical-Specific ARARs Table 5.2 Summary of Potential Action-Specific ARARs Table 5.3 Summary of Potential Location-Specific ARARs Table 6.1 Summary of Screening Management and Treatment Technologies Table 6.2 Approximate Volume and Weight of Contaminated Soil and Mining Waste Table 6.3 Approximate Dimensions, Volume, and Weight of Debris Table 6.4 Approximate Volumes of Hazardous and Non-Hazardous Waste Table 7.1 Comparative Analysis of Removal Action Alternatives

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LIST OF ATTACHMENTS

Attachment A Cultural Assessment Reports Attachment B Raw Analytical Results Attachment C Bureau of Land Management Technical Note: Risk Management Criteria For Metals At BLM Mining Sites Attachment D Detailed Analysis and Cost Estimate Calculations of Removal Action Alternatives

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LIST OF ACRONYMS

AOC Area of Contamination amsl Above Mean Sea Level ARAR Applicable or Relevant and Appropriate Requirements ATV All-Terrain Vehicle BAF Bioaccumulation Factor BLM Bureau of Land Management CERCLA Comprehensive Environmental Response, Compensation, and Liability Act COC Constituents of Concern CWM Chemical Waste Management of the Northwest, Inc. DOGAMI Department of Geology and Mineral Industries DRO Diesel Range Organic EE/CA Engineering Evaluation/Cost Analysis EP Extraction Procedure EPA U.S. Environmental Protection Agency ESA Endangered Species Act FDA Federal Drug Administration gpm Gallons Per Minute HDPE High Density Polyethylene HRMC Human Risk Management Criteria ISV In-situ Vitrification LDR Land Disposal Restriction MCL Maximum Contaminant Level mg/kg Milligrams Per Kilogram mg/l Milligrams Per Liter NCP National Contingency Plan NPS National Park Service NRCS Natural Resource Conservation Service NSTC National Science and Technology Center ng/l Nanograms Per Liter OAR Oregon Administrative Rules OB Open Burn OD Open Detonation OSC On-Scene Coordinator PAHs Polynuclear Aromatic Hydrocarbons PCBs Polychlorinated Biphenyls PCOCs Potential Constituents of Concern ppm Parts Per Million QA/QC Quality Control / Quality Assurance RAO Removal Action Objective RCRA Resource Conservation and Recovery Act RMC Risk Management Criteria SA Site Assessment SPLP Synthetic Precipitation Leaching Procedure

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LIST OF ACRONYMS (Continued)

SSL Soil Screening Level S/S Solidification/Stabilization SVOCs Semi-Volatile Organic Compounds TBC To Be Considered TCLP Toxicity Characteristics Leaching Procedure TDS Total Dissolved Solids TSD Transfer, Storage, and Disposal TPH Total Petroleum Hydrocarbons TRV Toxicity Reference Values VOCs Volatile Organic Compounds WQC Water Quality Criteria XRF X-Ray Fluorescence

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EXECUTIVE SUMMARY

The U.S. Department of Interior, Bureau of Land Management (BLM), Roseburg Oregon District Office authorized Dynamac Corporation (Dynamac) to develop an Engineering Evaluation/Cost analysis (EE/CA) for the Umpqua Abandoned Mine Lands (AML) Site, under Task Order BLM3-55R.

The Site is located in Douglas County Oregon, approximately 30 miles southeast of Roseburg, OR and is reached by traveling south on Interstate 5 to Canyonville, east on County Road 1, taking a left at County road 46 through Tiller. The mine focused on the mining, milling, and processing of cinnabar to produce mercury. A distillation process was used to amalgamate the ore into mercury. A significant amount of mining and milling equipment remains present on the Site to this day, in varying degrees of disrepair. The Site is characterized by narrow ridges, steep slopes, dense vegetation, and deep canyons. Drainage from the site enters an unnamed stream that flows through the mill area, and discharges to Stanley Creek. In 1999-2000, Dynamac corporation prepared a Site assessment (SA) Report for the Site. In 2000, BLM Conducted additional sampling activities to expand information contained in the SA.

The available analytical results from sampling of soil and mining waste indicate that waste material, primarily present in the partially collapsed main ore bin, fine ore bin, and condenser trough, exhibit highly elevated concentrations of mercury and area of significant concern. In general, this waste material is finely ground and is not in any form of containment, thus facilitating incidental contact and the potential for transport off site via surface water run off.

The sludge contained within the storage tank and the associated petroleum contaminated soil should be similarly be the subject of action which is protective of human health and the environment and minimizes impacts to on and off site soils, surface water and ground water.

The sediment sampling results indicate that the finely ground waste source material is being transported downgradient and beyond the site boundaries in the unnamed drainage and is finding its way into the neighboring stream channels of Stanley and deadman creeks and accumulating in the sediments. This is of particular concern because of the length of time that mercury can persist in soil and sediments, and the degree to which mercury bioconcentrates, biomagnifies, and transforms from a less toxic inorganic form to a more toxic organic form in fish and wildlife tissues. Concentrations of mercury in sediment greater than one part per million are considered high, and all three of the downgradient stream sediment samples exhibit values in excess of this concentration.

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To define the Remedial Action Objectives (RAOs) for the Site, the results of the site characterization and streamlined risk assessment were examined in an effort to construct removal goals which comply with the applicable or relevant and appropriate requirements (ARARs) and are protective of human health and the environment. Based on this process, the following RAOs were identified:

$ Eliminate or reduce human exposure to mercury and petroleum hydrocarbons in the mining waste material. $ Eliminate or reduce ecological exposure to mercury and petroleum hydrocarbons in the mining waste material. $ Eliminate or reduce off-site migration of mercury via surface runoff and wind dispersion. $ Eliminate or reduce the physical hazards associated with the mining equipment and related debris.

Based on the RAOs, general potential response actions and technologies were assembled into four Removal Action Alternatives which have been analyzed with respect to the evaluation criteria (effectiveness, implementability, and cost). These alternatives have been developed based on the known nature and extent of soil contamination and results of the human and ecological risk assessments and are described in the paragraphs to follow.

Under Alternative 1 (No Action), the current site conditions would continue and no removal actions would be implemented to control contaminant migration or to reduce toxicity or waste volume. This alternative does not meet the response goals or identified ARARs for the project. There are no capital or operating costs associated with the No Action alternative.

Alternative 2 (Institutional Controls) is moderately effective in mitigating the human health risk by fencing the area of contamination, but does not prevent ecological exposure, off-site transport of contaminants via the surface water or air pathways, and does not address the volume or toxicity of the contaminants. Since the contaminated soils, waste materials, mining structures, and debris will remain uncovered in this alternative, they remain a threat to human and ecological receptors which come into contact with it (although the fencing will mitigate much of the human health risk), and is still subject to erosion by wind and surface water. Nevertheless, the elements of Alternative 2 are critical parts of Alternative 3 and therefore may be a successful interim measure until funding is available to take further action. The estimated capital cost associated with this alternative was calculated to be approximately $3,393; operations and maintenance costs are expected to be approximately $1,280 per year.

Alternative 3 (Remove Waste Materials to an On-site Repository, Cap, and Revegetate) involves the removal of the contaminated soil, waste materials, and debris and disposal of the material in an engineered on-site repository. Removing the waste materials from the vicinity of the unnamed drainage to a designed repository provides a high level of environmental protection by preventing off-site transport via surface water. Consolidation and capping of the collapsed mining structures and contaminated soil and subsequent placement of institutional controls around the repository will reduce the mobility of mercury in the soil, eliminate air pathways, and serve as a barrier between site contamination and potential human and ecological receptors. This

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alternative contributes a very high degree of source control and long-term effectiveness. The short-term impacts to the environment during implementation of this alternative may include wildlife disturbance through noise and human activity during construction. The estimated capital cost associated with this alternative was calculated to be approximately $180,854; operations and maintenance costs are expected to be approximately $3,280 per year.

Alternative 4 (Off-Site Disposal) involves the complete removal of the mining structures, debris, the contaminated soils and waste materials and transportation and disposal of the material at an appropriate off-site facility. This alternative completely eliminates the principal threats posed by the release of the contaminated soils and mining structures from the site by isolating them from potential air, soil, and water exposure pathways. Alternative 4 provides the highest level of protection to the environment as well as human health. The estimated capital cost associated with this alternative was calculated to be approximately $850,252; operations and maintenance costs are expected to be approximately $1,000 for the first year only. After the first year, no operations and maintenance tasks are expected to be required.

Of the alternatives which have been analyzed, Alternative 3 (Remove Waste Material to an On- Site Repository, Cap, and Revegetate) appears as if it is the most appropriate alternative based on an analysis of these three evaluation criteria. Alternative 3 is effective in complying with ARARs and meeting the RAOs, and is more protective of human health and environment than Alternatives 1 and 2. Although Alternative 4 provides a greater degree of environmental protection, the costs do not appear justified based on the realized increases in environmental protection. Alternative 3 can effectively reduce the principle threats posed by the release of contaminants from the Site by reducing off-site transport via all perceived potential exposure pathways, and significantly reduces the mobility of these contaminants in air, soil, surface water, and groundwater, so as to present benefits in both the short- and long-term. With continued maintenance, this alternative presents adequate long-term benefits, as a properly designed repository with an appropriately designed, constructed, and maintained cap should have a long operational period.

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1.0 INTRODUCTION

The U.S. Department of Interior, Bureau of Land Management (BLM), prepared this Engineering Evaluation/Cost Analysis (EE/CA) for the Umpqua Abandoned Mine Lands (AML) Site (Site), Douglas County, Oregon.. This EE/CA has been prepared in accordance with the criteria established under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), sections of the National Contingency Plan (NCP) applicable to removal actions (40 CFR § 300.415 (b)(4)(I)). The EE/CA is also consistent with the U.S. Environmental Protection Agency (EPA) guidance document, Guidance on Conducting Non- Time Critical Removal Actions Under CERCLA.

The goals of the EE/CA are to:

$ Interpret and verify the results of previous studies at the Site; $ Address data gaps necessary to satisfy environmental review requirements and document the need for removal actions to address contamination on-site; $ Conduct streamlined human health and ecological risk assessments to determine the potential threats posed by contamination originating at the Site; $ Provide a framework for the evaluation and selection of potential response actions and applicable technologies; and, $ Satisfy administrative record requirements for improved documentation of removal action selection.

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2.0 SITE CHARACTERIZATION

2.1 Site Description and Background

2.1.1 Site Location

The Umpqua AML Site is located in Douglas County, OR, approximately 30 miles southeast of Roseburg, OR and is reached by traveling south on Interstate 5 to Canyonville, east on County Road 1, taking a left at County Road 46 through Tiller. BLM Road 30-2-13.0 is traveled for approximately 5.0 miles before taking a left onto BLM Road 29-2-26.0, which leads to the subject property. The legal description of the Site is Township 29 South, Range 2 West, Section 34, Willamette Meridian, and north latitude 43o01'04" and west longitude 122o55'55". The location of the site is shown in Figure 2.1.

2.1.2 Type of Facility and Operational Status

Development of the Umpqua Mine began in 1918. Approximately 1100 feet of underground workings were eventually developed, mostly during the 1920s and 1930s. Cinnabar ore was mined, milled, and processed by distillation to produce flasks of liquid mercury. Reported production of mercury was four flasks in 1929 and five flasks in 1943. Approximately 100 tons of low-grade ore was mined and treated at the adjacent Maud S. Mine. Some of the ore from this mine was treated at the Umpqua Mine. Tailings from processing were subsequently side cast near an unnamed mine drainage and may have washed into the adjacent streams below.

2.1.3 Structures/Topography

The Site contains a significant amount of mining and milling machinery from the crushing and milling processes. A map of the site and its surroundings is provided in Figure 2.2 and a detailed map showing the site features is shown in Figure 2.3. Features include a partially collapsed adit, ore car rails, a large hopper, rotary and brick furnaces, diesel storage tanks, stamp mills, amalgamation plants, and rails leading to a tailings pile, all of which are located just outside the private land boundary, on BLM land. The adit portal is between BLM and private land, approximately on the boundary between the two properties. Water flows from the adit at a rate estimated to be typically less than ten gallons per minute (gpm), passes through a culvert, and discharges to an unnamed drainage which traverses the mine property before flowing into Stanley Creek.

The Site is located mid-slope on a narrow ridge between 2,000 and 2,400 feet above mean sea level (amsl). The site is surrounded by mountainous terrain which is characterized by narrow ridges, steep slopes, and deep canyons. Drainage from the site enters an unnamed stream that flows through the mill area, and discharges to Stanley Creek. Stanley Creek subsequently discharges to Deadman Creek a short distance downgradient from its confluence with the unnamed drainage. Deadman Creek continues to the southeast discharging to the South Umpqua River approximately six miles downstream.

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2.1.4 Geology/Soils

Geology

The mine workings explored a fault zone that separated the Umpqua Formation from overlying andesite and tuff. The Umpqua Formation is composed of conglomerate, sandstone, and siltstone. Based on development information on the workings contained in early Department of Geology and Minerals Industries (DOGAMI) reports, it appears that the overlying units are less than several hundred feet thick. The fault zone is characterized by carbonatized and kaolinized andesite and tuff breccia. Spotty cinnabar mineralization was mined from the main fault zone and locally along transverse fractures with veinlets of calcite and calcedony associated with pyrite and marcasite.

Soils

Soil survey data for the area surrounding the Site is available from the National Resource Conservation Service (NRCS). Soils information which is pertinent to this EE/CA is summarized in Table 2.1. According to the survey, two dominant soil units are present at the Site and immediate surrounding areas; these are designated as 464G and 305F by NRCS. The maps based on the NRCS soil survey that show the location of these units in the area of the Site are presented in Figures 2.4 and 2.5. Additional information pertaining to the 464G and 305F soil units is provided in the paragraphs to follow.

Unit 464G

Composition

Klicktat soil and similar inclusions = 55 percent Harrington soil and similar inclusions = 35 percent

Setting

Landform: mountains Landscape position: side slopes Elevation: 1100 to 4000 feet

Typical Profile of the Klicktat Soil

Zero to 11 inches = dark reddish brown extremely gravelly loam 11 to 38 inches = dark brown and strong brown very gravelly loam 38 to 60 inches = yellowish red and strong brown very gravelly loam

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Properties and Qualities of the Klickitat

Depth: 60 inches or more to bedrock Drainage class: well drained Permeability: moderate Available water capacity: about 5.5 inches

Typical Profile of the Harrington Soil

Zero to 5 inches = dark reddish brown very gravelly loam Five to 28 inches = dark reddish brown very gravelly clay loam 28 to 34 inches = reddish brown extremely gravelly loam 34 inches = hard bedrock

Properties and Qualities of the Harrington Soil

Depth: 20 to 40 inches to hardrock Drainage class: well drained Permeability: moderately drained Available water capacity: about 3.0 inches

Unit 305F

Composition

Honeygrove soil and similar inclusions = 75 percent

Setting

Landform: mountains Landscape position: side slopes and ridges Elevation: 200 to 3000 feet

Typical Profile

Zero to 12 inches = dark reddish brown gravelly clay loam 12 to 30 inches = dak reddish brown clay 30 to 63 inches = dark red clay

Soil Properties and Qualities

Depth: 60 inches or more to bedrock Drainage class: well drained Permeability: moderately slow Available water capacity: about 9.0 inches

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2.1.5 Hydrology

The Site is located along an unnamed mine drainage which flows from the south, past the adit or “main tunnel” (F.16) from which it receives additional flow, through a culvert beneath BLM Road 29-2-26.0, through the main portion of the site where the majority of the mining equipment is present, and continues steeply downhill to the north towards Deadman Creek. After the confluence with the unnamed mine drainage which passes through the site, Deadman Creek flows southeast for approximately three miles before flowing into the South Umpqua River. The State of Oregon has designated all tributaries of the South Umpqua River for use as:

$ Public and Private Domestic Water Supply (with adequate pretreatment and natural quality to meet drinking water standards); $ Industrial Water Supply; $ Irrigation; $ Livestock Watering; $ Anadromous Fish Passage; $ Salmonid Fish Rearing; $ Salmonid Fish Spawning; $ Resident Fish and Aquatic Life; $ Wildlife and Hunting; $ Fishing; $ Boating: $ Water Contact Recreation; $ Aesthetic Quality; and, $ Hydro Power.

As such, the water quality criteria which are applicable to the site include those which are protective of human health (i.e., water and fish ingestion and drinking water criteria) and aquatic life (acute and chronic criteria).

2.1.6 Surrounding Land Use and Populations

The Umpqua Mine workings are located primarily on BLM land in an area where logging is prevalent. The timber on the adjacent private land recently was sold for harvest, and a request is currently pending to use BLM roads to haul such timber. The site is in forested land suitable for camping and other recreational purposes. The surrounding land is BLM ownership, except for an adjacent parcel of private ownership (the Maud S. Mine and related patented land) to the south.

2.1.7 Sensitive Ecosystems

Three threatened and two endangered species, are known to occur within the BLM Roseburg District. The northern spotted owl, marbled murrelet, and the bald eagle are listed as threatened species, whereas the American peregrine falcon and the Columbian white-tailed deer are

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endangered (Espinosa, 1993). Species such as blacktail deer, black bear, cottontail rabbit, and silver grey squirrel are also known to inhabit the area (Norecol Inc., 1988). It should also be noted that the affected streams are likely habitat for Coho salmon, coastal cutthroat trout, and coastal steelhead, all of which are either protected under the Endangered Species Act (ESA) or candidates for listing under the ESA.

2.1.8 Cultural Resources

The cultural and historical resources at the Site were originally evaluated in 1999 by Heritage Resource Associates (Heritage). In the “Preliminary Cultural Assessment of the Umpqua Mine” report, Heritage provided some recommendations based on their evaluations.

“The Umpqua Mine Site appears to have a strong potential eligibility for listing on the National Register of Historic Places and, pending a final determination, should be managed in recognition of that potential. In the interim, any adjacent project by Roseburg District of the Bureau of Land Management should be undertaken only after consultation with the District’s Cultural Resource staff and designed so as to minimize impacts on the integrity of the mine site to the greatest degree feasible. The Umpqua Mine should be adequately signed with notices that it is a significant cultural resource and that any tampering, artifact collection or vandalism will be prosecuted to the full extent of the law.”

Additional recommendations for historic documentation and management planning for the Site include, but are not limited to, an additional review of the ownership and development history of the Site, field work to locate additional resources sites, physical inspection of the Site, and a development of a management plan for extent resources determining best practice from a public safety, resource management and cultural resource standpoint.

Early in 2001, Heritage began mitigation documentation at the Site. The documentation was conducted consistent with Oregon State Historic Preservation Office Tier I requirements. This documentation includes photographs and measured drawings of all major structures and has been assembled into a report suitable for distribution to various repositories.

Both the 1999 and 2001 Heritage reports are included with this EE/CA in Attachment A.

2.1.9 Meteorology

The climate of the area is generally dry in the summer, and relatively mild throughout the year. According to data from Myrtle Creek, the average annual minimum and maximum temperature is 42.4 oF and 65.9 oF, respectively. Average summer temperatures range from 66.4 to 81.5 oF, while winter temperatures average 35.1 to 50.6 oF. The total annual precipitation for 1998 was 55.41 inches, while average annual snowfall is 6.7 in.

2.2 Site Waste Characteristics

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Prior to the Site Assessment conducted by Dynamac in 1999-2000, no studies had previously been conducted at the Site. However, based on the prior use of the site it was hypothesized that mercury could exist within the plants, waters, and soils of the area. Another concern is the mobilization of mercury into the environment by logging. Other wastes, such as heavy metals, may be contained in the multiple crushing, milling, and processing facilities located on-site. An open adit with rails also leads to a tailings pile. Surface water may be contaminated from tailings which were dumped into the stream during operations. Furthermore, diesel fuel, tar, or another petroleum compound may have leaked from an above ground storage tank into the soil. Asbestos is likely present in the thermal system insulation on the process equipment which is still at the site, but this has not been confirmed by sampling. While the asbestos containing material does not appear to merit immediate removal, it may become necessary to dispose of it separately from the metal debris in the event that the mining equipment and related debris are taken off-site.

Mercury is a cumulative poison which has harmful effects when present in fish and wildlife. It is the heavy metal most toxic to fish. Fish eating birds, mammals, and reptiles also risk exposure in mercury contaminated areas. Human exposure to methyl mercury is almost entirely due to consumption of fish. Mercury may impact the brain, the central nervous system, and the kidneys. Many mercury compounds can irritate the skin and eyes, causing dermatitis and ulceration of the cornea (NPS, 1997).

Mercury can survive in the environment for many years, and can fluctuate from inorganic to organic forms. However, most mercury in the air, water, and soil is inorganic. Mercury is very reactive in the environment, readily undergoing phase, species and redox changes. Sedimentation and evasion are the primary sinks of mercury in the aquatic environment, and in sediments, mercury often is bound to sulfides. During flood events, mercury becomes re- suspended from bottom sediments, and flows downstream, often accumulating in fish. Mercury normally remains within soil, and rarely is transported to groundwater (NPS, 1997).

2.3 Previous Investigations

In 1999-2000, Dynamac Corporation prepared a Site Assessment (SA) Report for the Umpqua Mine Site (Dynamac, 2000). The objectives of the SA were to: (1) identify and characterize the nature and extent of environmental contamination at the Site; (2) quantify, to the extent possible, the damage caused to the quality of the surrounding environmental media (i.e., surface water, groundwater, and soil) and local flora and fauna as a result of the mining activities; (3) evaluate the potential for off-site impacts to human health and the environment; and, (4) collect information necessary to make generalized recommendations regarding future activities at the Site.

No previous environmental investigations are known to have been carried out at Site prior to the Dynamac SA. A historical assessment was conducted in by Heritage Research Associates in 1999; a report detailing the findings of this assessment is forthcoming.

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In 2000, BLM conducted additional sampling activities to expand on the information contained in the SA. This work included two rounds of additional surface water sampling using Method 1631 for mercury and soil sampling using Method 6200 (X-ray fluorescence spectrometry or XRF).

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3.0 SOURCE, NATURE, AND EXTENT OF CONTAMINATION

3.1 Waste Source and Soil

3.1.1 Sampling

Three sampling activities have taken place at the Site. In 1999, Dynamac sampled surface soils and suspected waste materials at the Site and analyzed the samples for mercury. During 2000, personnel from the BLM National Science and Technology Center (NSTC) sampled surficial and subsurface soils in a grid at the site using a portable XRF instrument. In 2001, BLM Roseburg District Office personnel collected five additional samples for Toxicity Characteristic Leaching Procedure (TCLP) and total mercury analysis.

During the 1999 sampling, samples of potential waste source material were collected from areas of suspected contamination from representative locations throughout the site to determine the concentrations, if any, of the potential constituents of concern (PCOCs) for these areas. A total of six waste source samples were collected; a summary of the number, location, and objectives of the waste source sampling is presented in Table 3.1. The sample locations are shown in Figure 3.1. Site features are labeled using nomenclature presented in the mapping performed by BLM Roseburg District personnel, later digitized by Heritage Research Associates. Collection of field duplicate quality assurance/quality control (QA/QC) samples did not occur at the discretion of the on-site BLM Task Manager.

In addition to collecting the samples above, the approximate volume of each waste unit was visually estimated by pacing off the boundaries or using other field evaluation methods. Using the waste unit dimension data obtained in the field, coupled with measurements obtained from the Heritage Research Associates digitized map of the site, the approximate volumes of the waste units were calculated and are presented in Table 3.2. It should be noted that many of the waste units are located in areas which, due to the physical hazards associated with the site, could not be closely examined. For this reason, it is expected that a small amount of error is associated with these volume calculations. More accurate measurements may be necessary during future work.

During the 2000 sampling, in an effort to better map the extent of mercury contamination, NSTC personnel placed a grid with 40 foot centers over the site to collect in-situ XRF measurements for nine metals.

The 2001 sampling was conducted to obtain a better understanding of the relationship between total mercury concentration and TCLP results. Specifically, samples were collected in order to determine the approximate total mercury concentration which will cause the contaminated material to fail TCLP (0.2 mg/l), thereby requiring classification as a hazardous waste. This relationship, once established, would allow for more precise volume estimates when evaluating off-site disposal options. Sample locations for the 2001 sampling are presented in Figure 3.3.

3.1.2 Analytical Results

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The waste source samples were analyzed for mercury only using EPA Method 7471A which has a method detection limit of 0.1 milligrams per kilogram (mg/kg). The results of these analyses were subsequently compared to the following criteria: Select samples were also prepared using the Synthetic Precipitation Leaching Procedure (SPLP) Extraction (EPA Method 1312), a method which approximates the effects of rainfall on the material; the resultant leachate was subsequently analyzed using EPA Method 7470A to determine the concentration of mercury in the liquid that is prone to leach out of the waste materials during precipitation events. The method detection limit for EPA Method 7470A is 0.05 milligrams per liter (mg/l). A full summary of the analytical results for the waste source mercury analysis is provided in Table 3.3.

As the results show, mercury is present in high concentrations in several of the waste units, particularly in the material found in the condenser trough (F.8) (Sample UMS-WS-4) and in the depression between the flume (F.11) and collapsed condenser shed (F.8.7) (Sample UMS-WS-5). The mercury concentrations were high enough in all of the waste source samples to require the laboratory to dilute them for analysis, by as much as a factor of one thousand, as shown in Table 3.3.

With the exception of sample UMS-WS-1, all the waste source samples exceed the concentration of mercury found in the background soil sample by a minimum of two orders of magnitude.

The material collected from one of the tailings piles (F.17) was the only waste unit which did not show concentrations of mercury above the BLM HRMC (camper value) for mercury of 40 mg/kg. The remaining samples exceed this criteria by as much as 20 times, indicating that the waste material poses a risk through even incidental contact by site visitors. Coupled with the close proximity to an access road and the likelihood of potential visitors to be drawn to investigate the vast amount of mining equipment which is readily visible, the risk of exposure is relatively high. Concentrations of mercury at or near 1,000 ppm, as found in samples UMS-WS- 4 and UMS-WS-5, must be considered high risk (See Section 4.4).

Two of the waste source samples, as well as the background soil sample, were prepared with the SPLP and the leachate was analyzed. The results indicate that leaching of mercury is occurring in only one of these three samples, UMS-WS-4, the sample collected from the condenser (F.8) trough. The analysis of the leachate from this sample showed a mercury concentration of 0.28 mg/l. This level exceeds the similar Toxicity Characteristic Leaching Procedure (Method 1311) regulatory level for mercury of 0.2 mg/l. Solving for 0.2 mg/l, one computes an approximate corresponding total mercury level of 543 mg/kg. It is assumed therefore, that waste and soil concentrations exceeding 543 mg/kg will fail the TCLP and will require disposal as hazardous waste. The SPLP results would seem to suggest that leaching of this magnitude also takes place in those waste units with similar total concentrations of mercury such as that found in the depression to the north of the collapsed condenser shed (F.8.9).

The XRF sample results measured in November 2000 are shown in Table 3.5. Metal was the only metal found to be elevated. Five sample splits were analyzed by a laboratory for confirmation. The split results were used to determine the accuracy of the XRF results using linear regression. The split results were found to be higher than the XRF results. The XRF

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results in Table 3.5 and Figure 3.2 have been corrected for the low XRF bias. The mercury results are shown graphically in Figure 3.2. It may be seen that the highest concentrations are found in the ore chute and condenser/waste chute areas, and these concentrations are consistent with those reported in 1999. Table 3.5 also shows the vertical distribution of mercury contamination at several locations. For concentrations <100 ppm, concentrations declined to less than 40 ppm within one foot. Concentrations >100 ppm declined to <40 ppm within two feet.

In April 2001, BLM conducted additional sampling of contaminated soils and mining waste to determine the amounts of total and leachable mercury in the material. The raw analytical data for this sampling event are provided in Attachment B. Five samples were collected for the purpose of obtaining a more accurate correlation between total mercury and TCLP values than was discussed earlier in this section as extrapolated from SPLP results. Unfortunately, as shown in Table 3.4, the results show no correlation, presumably due to the heterogeneity of the waste material. The highest recorded total mercury concentration recorded for the 2001 sampling event was 730 ppm, found in sample UMS-TCLP-3. One would expect the highest TCLP results from this sample; however, the TCLP result for UMS-TCLP-3 was not only below the TCLP result for a sample with a considerably lower total TCLP value (UMS-TCLP-1), it was below the 0.2 mg/l standard for hazardous waste determination. As a result, for the purposes of calculations made within this EE/CA, the 543 ppm value previously discussed in this section will be used as the total mercury concentration cutoff value for material requiring disposal as hazardous waste. Nevertheless, it should be recognized that disposal volume estimates will have a level of error associated with them due to the limitations of the available data. It is recommended and expected that additional sampling be performed in the form of waste profiling to the satisfaction of the disposal facility in the event that off-site disposal is determined appropriate.

One 1999 sample was collected for petroleum hydrocarbons. Sample UMS-S-2, collected from the visibly stained area of directly below the spigot on the end of the above ground storage tank (F.8.4), was analyzed using EPA Method 8015A for total petroleum hydrocarbons (TPH) diesel range organic (DRO) compounds. The results of this analysis are summarized in Table 3.6.

The results indicate that petroleum contamination is present in the diesel range at this location. Due to the age of the tank, it is difficult to estimate the amount of material which has been released over time; however, it is estimated that the total amount is less than 42 gallons and under the reportable quantity for petroleum related spills. Nevertheless, this material should be managed according to Oregon Administrative Rules (OAR) §340 Divisions 47 and 108 because it may be in danger of impacting groundwater or other waters of the state due to its close proximity to the unnamed mine drainage.

3.1.3 Volumes

Approximately 27 cubic yards of mining waste material containing elevated levels of mercury and qualifying as hazardous waste is present on-site in the fine ore bin (F.8.7), condenser shed (F.8.9), and the condenser trough (F.8). The waste material is, in general, fine grained and contains high concentrations of mercury. An additional 131 cubic yards of soils near the main ore bin and condenser may exceed 543 ppm mercury and require disposal as hazardous waste.

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Another 20 cubic yards from the main ore bin and 341 cubic yards of contaminated soils which are not expected to be characterized as hazardous but exceed the RMC for the camper (40 ppm) are expected to be disposed as non-hazardous waste.

Using Surfer, the estimated volumes of contaminated soil present at the Site are as follows:

$ Area > 543 ppm = 1,770 square feet x 2' depth = 131 cubic yards $ Area > 40 ppm and <543 ppm = 9,200 square feet x 1' depth = 341 cubic yards $ Total > 40 ppm = 472 cubic yards

Due to the high mercury concentrations observed and the relatively high accessibility of the site, it is recommended action take place at the site which is protective of both human health and the environment. This action may include limited removal of the waste material which is of the highest concern and/or implementation of institutional controls (e.g., fences and warning signs) to isolate the material from potential site visitors and surface water runoff controls to prevent the material from entering the unnamed mine drainage or leaving the site by other means. Due to the physical hazards associated with the partially collapsed adit and the large amount of mining equipment and structures (often extremely large, heavy, and precariously balanced), it is recommended that the mine features also be evaluated on an individual basis to determine whether or not institutional controls, stabilization, or removal is appropriate.

The sludge contained within the storage tank (F.8.4) and the associated petroleum contaminated soil (a total quantity of approximately three cubic yards of material) should similarly be the subject of action which is protective of human health and the environment and minimizes impacts to on and off-site soils, surface water, and groundwater. This may include the installation of institutional and/or surface water runoff controls, or limited removal and disposal of in a manner consistent with applicable State and Federal regulations.

3.2 Surface Water and Sediment

3.2.1 Sampling

During 1999, surface water and sediment samples were collected from a total of six locations both on and off the site to determine the concentration of mercury, if present, and to determine the extent, if any, of off-site migration of contamination from the site via the surface water pathway. At each sample location, filtered surface water samples were collected to determine the dissolved concentrations of mercury. The water flowing from the adit was also submitted for laboratory analysis of major anions, pH, total dissolved solids (TDS), and alkalinity. Sediment was collected at each of the six locations for determination of mercury concentrations. A summary of the number, location, and objectives of the surface water and sediment sampling is presented in Table 3.7 and the sample locations are shown in Figure 3.1. During the sampling activities, field measurements of flow, pH, temperature, and conductivity were taken at each of the sample locations. Table 3.8 provides a summary of the field data.

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The field results show elevated conductivity results at the downgradient Stanley Creek, unnamed mine drainage, and adit flow sample locations, indicating elevated total metals concentrations at these locations. It is most likely that the elevated total metals concentrations are present in the form of iron (from all the rusted equipment in the area) or hardness elements (calcium and magnesium resulting from long contact times between water coming out of the adit and host rock). However, this cannot be confirmed with the information obtained during this SA because the scope of the investigation included mercury analysis only.

Due to the extremely low concentrations specified by the Oregon Fresh Water Chronic and Water and Fish Ingestion Criteria, the analytical method used to analyze the surface water samples collected during this SA (EPA Method 245.1) did not have a low enough detection limit to evaluate whether or not the surface water meets these two thresholds. Recently, the EPA has approved a new method (EPA Method 1631) to measure mercury accurately at ambient water quality criteria levels. This method allows determination of mercury at a level of 0.0000005 mg/l (0.5 nanograms per liter), approximately 400 times lower than the level achieved by other previously approved mercury methods. However, the majority of environmental laboratories are not capable of performing this analysis at the time of the 1999 sampling because most are not equipped with the gold trap atomic fluorescence spectrometer or clean room environment which are required. Because of the need for lower detection limits, BLM personnel resampled UMS- SW-1 through UMS-SW-5 locations during higher flow conditions on May 12, 2000 and again on June 15, 2000 using the new Method 1631.

3.2.2 Analytical Results

The 1999 surface water samples were analyzed for the mercury using EPA Method 245.1, which has a method detection limit of 0.00020 mg/l. At this detection limit, no mercury was detected in any of the six surface water samples collected during the SA. The results of these analyses are to be compared to the following criteria: Oregon Water Quality Criteria (WQC) for the protection of aquatic life (acute and chronic values for fresh water) and for protection of human health (water and fish ingestion values, as well as the drinking water maximum contaminant level [MCL]) and BLM HRMC in Surface Water (camper value). Table 3.9 displays the 1999 and two 2000 sampling results and the water quality criteria.

These results show that two sampling locations have greater than twice background mercury concentrations, the unnamed mine drainage (UMS-SW-4) below the site and Stanley Creek below the confluence with the unnamed drainage (UMS-SW-3). These locations also exceed Oregon fresh water chronic aquatic life criteria.

Sample UMS-SW-6, which consisted of the water flowing from the main tunnel (F.16), was also analyzed for the following general parameters: major anions (chloride, nitrate, nitrite, sulfate), TDS, pH, and alkalinity. The results of this analysis is shown in Table 3.10.

The sediment samples were analyzed using EPA Method 7471A, which has a method detection limit of 0.1 mg/kg. The results of the mercury analysis for samples collected at locations that are

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believed to be impacted by the site are compared to the BLM HRMC for mercury in sediment (camper value) for sediments and the results of the two background samples (UMS-SW-2 and UMS-SW-5, collected from upgradient locations on Deadman Creek and Stanley Creek, respectively). A full summary of the analytical results for the sediment mercury analysis is provided in Table 3.11.

All three of samples collected within the areas of potential influence of the site exhibit mercury concentrations that are significantly higher than those found in the upgradient/background samples. This is the same pattern of highest concentrations found in surface water. The sediments collected from Deadman Creek in a location upgradient of the confluence with Stanley Creek did not show detectable concentrations of mercury; however, the downgradient sample concentration was found to be 1.7 mg/kg. With the method detection limit of 0.1 mg/kg, this shows that at a minimum, the downgradient sample concentration is 17 times the background concentration. The same is shown in the Stanley Creek sample pair; the upgradient/background sample had a concentration of 0.38 mg/kg and the downgradient sample had a concentration of 8.2 mg/kg, or nearly 22 times background. The sample collected just downgradient from the northern site boundary revealed a concentration of 8.0, which mirrors the result found in the Stanley Creek downgradient sample. No mercury was detected in the sample collected from the adit flow.

3.3 Summary of Results

The unnamed drainage below the mine contained 1,900 ng/L mercury. Below the confluence with Stanley Creek, the mercury concentration was 20.5 ng/L, about three times background and greater than chronic water quality criteria for mercury. These results were confirmed by the sediment results and show the Site as the principal source of mercury in the watershed.

The sediment sampling results indicate that the finely ground waste source material is being transported downgradient and beyond the site boundaries in the unnamed mine drainage and is finding its way into the neighboring stream channels of Stanley and Deadman Creeks and accumulating in the sediments. This is of particular concern because of the length of time that mercury can persist in soil and sediments, and the degree to which mercury bioconcentrates, biomagnifies, and transforms from a less toxic inorganic form to a more toxic organic form in fish and wildlife tissues. Concentrations of mercury in sediment greater than 1 mg/kg are considered high, and all three of the downgradient stream sediment samples exhibit values in excess.

Approximately 50 cubic yards of waste material, primarily present in the partially collapsed main ore bin, fine ore bin, and condenser trough, exhibit highly elevated concentrations of mercury and are of significant concern. In general, this waste material is finely ground and is not in any form of containment, thus facilitating incidental contact (i.e., dermal or via inhalation) and the potential for transport off-site via surface water runoff. Another 720 cubic yards of soil contaminated with mercury in excess of 25 ppm is found around the main ore bin and condenser.

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The sludge contained within the storage tank (F.8.4) and the associated petroleum contaminated soil (a total quantity of approximately three cubic yards of material) should similarly be the subject of action which is protective of human health and the environment and minimizes impacts to on and off-site soils, surface water, and groundwater.

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4.0 STREAMLINED RISK ASSESSMENT

Mining activities at the Site have probably influenced Stanley and Deadman Creek since the late 1800s. Mine waste generated from mining activity has contributed mercury into water, stream sediments and soils. The area is used for fishing, logging and recreation. Recreational demands are increasing at the site where exposure to relatively high metal concentrations in tailings, sediments, and surface waters exist.

To address these issues, BLM developed acceptable multi-media risk management criteria (RMC) for the constituents of concern (COCs) as they relate to human use and wildlife habitat on or near BLM lands. The primary objective of this section is to perform a streamlined risk assessment for the site and to establish the magnitude of risk to human health and wildlife. RMCs for soil, sediment, fish and water protective of human receptors for the metals of concern were developed using available toxicity data and standard EPA exposure assumptions. Acceptable soil and sediment concentrations protective of wildlife receptors (ecological RMCs) for the metals of concern were developed using toxicity values and wildlife intake assumptions reported in the current ecotoxicology literature.

The COCs and migration pathways were identified from historical information and site evaluation. The COC selection process utilized chemicals documented to have been released to surface water and observed contamination in tailings at the Site. Human and ecological COCs for Umpqua Mine tailings are limited to mercury. Potential receptors, receptor exposure routes, and exposure scenarios were identified from on-site visits and discussions with BLM personnel. Figure 6 shows the site conceptual model. Representative wildlife receptors at risk were chosen using a number of criteria, including likelihood of inhabitation, and availability of data.

4.1 Human Health Risk Assessment

The human exposure scenarios were developed to provide realistic estimates of the types and extent of exposure which individuals might experience to the metals of concern in the water, soils, and sediments on BLM property. Such exposures might occur to individuals who use BLM lands for camping, or all-terrain-vehicle (ATV) driving, or individuals who work on BLM lands. Contamination may migrate from the BLM tracts to adjoining property.

The RMC correspond to either a target excess cancer risk level of 1 x 10-5, or a target noncancer hazard index of 1.0. In the case of metals posing both carcinogenic and noncancer threats to health, the lower (more protective) concentration was selected as the RMC. The concept behind the RMC is that people will not experience adverse health effects from metal contamination on BLM lands in their lifetimes, while exposure is limited to soil, sediments, and waters with concentrations at or below the RMC. A target excess cancer risk of 1 x 10-5 means that for an individual exposed at these RMC, there is only a one in a hundred thousand chance that he would develop any type of cancer in a lifetime as a result of contact with the COCs. A hazard index of <1.0 means that the dose of noncancer metals assumed to be received at the site by any of the receptors in a medium is lower than the dose that may result in any adverse noncancer health effects. The RMC are protective for exposures to multiple chemicals and media. Lead RMC for

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the child receptors were determined from EPA's Integrated Exposure Uptake Biokinetic Model (EPA, 1993) and other EPA regulations and guidance. The human health criteria are found in Attachment C.

Ingestion of mercury via fish consumption may be a concern in Stanley and Deadman Creeks (Umpqua tailings). The Food and Drug Administration action level for mercury in fish is 1.0 ppm (wet weight; assumes 7 oz. of fish per week) and some states issue health advisories when fish tissue monitoring exceeds the FDA level.

4.2 Ecological Risk Assessment

Wildlife in Deadman Creek tributaries may be exposed to metal contamination via several environmental pathways. The potential exposure pathways include soil and sediment ingestion, vegetation ingestion, surface water ingestion, and inhalation of airborne dust. Ecological RMC have been established for metals in soil and sediments. This has been accomplished using the best data available, including: ecotoxicological effects data for the metals of concern, wildlife receptors representative of the Sierran Steppe ecosystem, body weights and food intake rates for each receptor, and soil ingestion rates for each receptor.

The site lies near the interface of the Sierran Steppe and the Cascade Mixed Forest Province (Bailey, 1995). The wildlife receptors evaluated for this area are: deer mouse, mountain cottontail, mule deer, elk, mallard, Canada goose, and trumpeter swan.

The literature was surveyed for toxicity data relevant to either wildlife receptors at the site or to closely related species. In the absence of available toxicity data for any receptor, data were selected on the basis of phylogenetic similarity between ecological receptors and the test species for which toxicity data were reported. Soil ingestion data for each receptor were obtained from a recent study on dietary soil content of wildlife from the U.S. Fish and Wildlife Service (Beyer, et. al., 1994). Where no dietary soil content data were available for a particular receptor, the soil content was assumed to be equal to that of an animal with similar diets and habits. The amount of soil ingested by each receptor was estimated as a proportion of their daily food intake (Beyer, et. al., 1994). The food intake in grams for each receptor was calculated as a function of body weight (Nagy, 1987).

RMC were calculated for each chemical of concern in soil based upon assumed exposure factors for the selected receptors, and species- and chemical-specific toxicity reference values (TRVs). Essentially, the TRVs represent daily doses of the metals for each wildlife receptor that will not result in any adverse toxic effects. TRVs were computed by metal of concern for each wildlife receptor/metal combination for which toxicity data were available. Phylogenetic and intraspecies differences between test species and ecological receptors have been taken into account by the application of uncertainty factors in derivation of critical toxicity values. These uncertainty factors were applied to protect wildlife receptors which might be more sensitive to the toxic effects of a metal than the test species. The uncertainty factors were applied to the test species toxicity data in accordance with a method developed by BLM. In accordance with this system, a divisor of two (EPA, 1990) was applied to the toxicity reference dose for each level of

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phylogenetic difference between the test and wildlife species, i.e. individual, species, genus, and family. The wildlife RMC for soil and sediment are found in Attachment C. For aquatic life protection, Oregon water quality standards and sediment criteria (Effects Level-Medium) were used (Ingersoll et al, 1996).

4.3 Uncertainty Analysis

Toxic doses for each metal were selected from the literature without regard to the chemical speciation that was administered in the toxicity test.

The process of calculating human health RMC, using a target hazard quotient and target excess lifetime carcinogenic risk, has inherent uncertainty. The COCs may have synergistic (or antagonistic) effects on human or wildlife receptors. Cumulative effects were quantitatively dealt with for the human assessment, although not all metals are elevated at each millsite. Additionally, it is improbable that human receptors would be exposed concurrently via all possible exposure pathways, although this has been assumed for conservatism (Ford, 1996). There is uncertainty in deriving wildlife RMCs due to the lack of toxicity data for these species. A standard uncertainty factor approach was used for interspecies extrapolation (Ford, 1996).

The COCs may have synergistic (or antagonistic) effects on human or wildlife receptors. Cumulative effects were quantitatively dealt with for the human assessment, although not all metals are elevated at each millsite. Additionally, it is improbable that human receptors would be exposed concurrently via all possible exposure pathways, although this has been assumed for conservatism (Ford, 1996). There is uncertainty in deriving wildlife RMCs due to the lack of toxicity data for these species. A standard uncertainty factor approach was used for interspecies extrapolation (Ford, 1996).

4.4 Risk Assessment Results

Table 4.1 compares the maximum media concentrations at the site with the selected appropriate RMCs (see Attachment C). The ratio of the environmental media concentration to the RMC is analogous to a hazard quotient of 1.0; that concentration that should present negligible risk. Media concentrations exceeding RMCs for humans or wildlife greater than 1.0 are flagged "+"; these occurrences may pose a chronic threat. Media concentrations exceeding RMCs by more than 10 and 100-fold for humans or wildlife are flagged as “++” and “+++”, respectively. Most significant are the >100 fold exceedances of mercury in the waste, soil and surface water, placing this site in the extremely high risk category according to the RMC (Ford, 1996).

Another comparison may be made with the use of EPA Soil Screening Levels (SSLs) for mercury: (inhalation) = 10 milligrams per kilogram (mg/kg), ingestion = 23 mg/kg (EPA, 1996). These SSLs are for residential land use and are not as applicable as the RMC.

Using the sample with the highest concentration of metals in the surface water at these sites, the sample UMS-SW-4 exceeds Oregon water quality standards for mercury during the 2000

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sampling. The Oregon water quality standards include a standard for protection of aquatic life for acute (not shown) and chronic exposure (OR-FWC) which is exceeded and for human health (OR-MCL) which is not exceeded (but close). Human mercury ingestion via fish consumption may be a concern in Stanley and Deadman Creeks, particularly Deadman Creek as the affected portion and flow of Stanley Creeks are quite small. As stated previously, mercury is bioaccumulated in the aquatic food chain from surface water. Higher trophic levels such as fish accumulate the most with a recent 50th percentile bioaccumulation factor (BAF) of 1.6 x 106 at trophic level 3 (EPA, 1997). There is an uncertainty associated with the use of this number of at least five. Using the Deadman Creek as a probable fishery with a maximum mercury concentration of 6.5 ng/L, and multiplying times the BAF yields an estimated fish tissue concentration of 10.4 mg/kg or ppm, plus or minus 5 ppm. The FDA action level for allowable amounts of mercury in commercially sold fish is 1 ppm, hence there is concern that fish in Deadman Creek may exceed the FDA fish tissue action level. Note however, that the upgradient samples from Deadman Creek contained approximately the same amount of mercury, hence there must be other, probably naturally-occurring sources in the watershed.

Containment of the mine waste will eliminate risks from direct contact and will reduce release of mercury to Stanley and Deadman Creek, help achieve ambient water quality standards and reduce the threat of mercury contamination of fish.

4.5 Removal Action Criteria

The camper RMC shown in Table 4.1 are proposed to be the removal criteria for waste materials and soil. As stated in Section 3.1.2, waste and soil with total mercury exceeding 543 mg/kg will be disposed as hazardous waste based on SPLP results. It has been shown that tailings are migrating into the stream below the Site. Since the risk criteria are based on ingestion and inhalation, mean surficial concentrations of soil/tailings exceeding these criteria will be removed or covered, and erosion of the dam will be part of the removal. Correction of the release of the tailings will enhance water and sediment quality in Stanley and Deadman Creek and reduce fish accumulation of mercury.

In addition to the mercury hazard at the site, the potential physical hazards associated with the steep slopes, partially collapsed adit, antiquated mining equipment, and related debris at the site must be considered as well when evaluating future site activities. The site is characterized by a relatively large amount of mining equipment and structures which are often extremely large, heavy, and precariously balanced. The proximity of these structures to BLM Road 29-2-26.0 increases the likelihood of visitors to the site, and the poor condition of the equipment, the steep slopes, and open adit present numerous opportunities for injury. In order to be protective of human health, it is recommended that the mining equipment be closely evaluated, prioritized for isolation, removal, or stabilization as soon as possible.

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5.0 IDENTIFICATION OF REMOVAL ACTION SCOPE, GOALS, AND OBJECTIVES

The Removal Action Objectives (RAOs) to be discussed in Section 5.1 have been developed based on an analysis of the known sources of contamination, the nature and extent of contamination, the results of the human health and ecological risk assessments, and the applicable or relevant and appropriate requirements (ARARs) that have been identified. The RAOs have generally been developed to control the contamination sources, and to eliminate the potential for exposure of human and ecological receptors to site contamination.

5.1 Definition of Removal Action Objectives

The general evaluation criteria for the analysis of potential removal actions, as defined in the EPA document Guidance on Conducting Non-Time-Critical Removal Actions Under CERCLA (1993), are effectiveness, implementability, and cost. These criteria are discussed in detail in Section 6.2. To define the RAOs for the Site, the results of the site characterization and streamlined risk assessment were examined in an effort to construct removal goals which comply with the ARARs and are protective of human health and the environment. The RAOs are to:

$ Eliminate or reduce human exposure to mercury and petroleum hydrocarbons in the mining waste material. $ Eliminate or reduce ecological exposure to mercury and petroleum hydrocarbons in the mining waste material. $ Eliminate or reduce off-site migration of mercury via surface runoff and wind dispersion. $ Eliminate or reduce the physical hazards associated with the mining equipment and related debris.

The proposed removal action must address the RAOs, and the future use of the property must be consistent with these objectives. As a result, both the proposed removal action and the potential future land use alternatives will be evaluated in subsequent sections to determine the extent to which they meet these RAOs. Although immediate and 100% attainment of the RAOs is not required for a removal action, it is considered to be a goal which is desirable pending availability of effective technologies and funding.

5.2 Removal Action Schedule

The BLM has determined that a non-time-critical removal action is appropriate at the Site. The removal could commence within six to twelve months following approval of this EE/CA. Based on past experience with the implementation of removal action technologies similar to those proposed in this EE/CA, it is estimated that any removal action undertaken can be completed within one year, if funding is available.

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5.3 Applicable or Relevant and Appropriate Requirements

The lead Federal agency or designated on-scene coordinator (OSC) is responsible for the identification of ARARs of all environmental laws that pertain to any CERCLA removal actions. As defined in the Guidance on Consideration of ARARs During Removal Actions (EPA, 1991):

“Applicable requirements are cleanup standards, standards of control, and other substantive requirements, criteria or limitations promulgated under Federal environmental or State environmental or facility siting laws that specifically address a hazardous substance, pollutant, contaminant, remedial action, location or other circumstances found at a CERCLA site.

Relevant and appropriate requirements are cleanup standards, standards of control, and other substantive requirements, criteria, or limitations promulgated under Federal environmental or State environmental or facility siting laws that, while not ‘applicable’ to a hazardous substance, pollutant, contaminant, remedial action, location or other circumstances at a CERCLA site, address problems or situations sufficiently similar to those encountered at the CERCLA site and are well-suited to the particular site.

...Other information To Be Considered (TBC) generally falls within three categories: health effects information with a high degree of credibility; technical information on how to perform or evaluate site investigations or response actions; and policy.

The ARARs presented and evaluated for this EE/CA are presented in three groups as follows:

$ Chemical specific standards established for specific chemicals found on the site, $ Location specific restrictions based on the location of the site, and $ Action specific limitations on “actions” associated with a CERCLA removal action.

The matrix presented in Tables 5.1, 5.2, and 5.3 identify the major Federal and State environmental laws but may not be entirely inclusive. The process of identifying additional ARARs or modifying this initial determination will continue as removal action alternatives are selected and further developed. Additionally, the designation of the applicability of Federal and State laws is ultimately the responsibility of the OSC. The designations suggested in this EE/CA should be used as guidance when working with Federal and State regulators involved in the final removal action.

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6.0 IDENTIFICATION AND ANALYSIS OF MANAGEMENT AND TREATMENT TECHNOLOGIES

6.1 Introduction

According to 40 CFR 300.415, the purpose of an EE/CA is to analyze potential Removal Action Alternatives based on current site conditions to address contamination present at the Site. The alternatives are evaluated and developed through the criteria suggested in the EPA document, Guidance on Conducting Non-Time-Critical Removal Actions Under CERCLA. Specifically, the Removal Action Alternatives have been developed and analyzed against the RAOs defined in Section 5.1 and the evaluation criteria defined in Section 6.2.

The development and analysis of Removal Action Alternatives involves four steps. In Section 6.3.1, the general categories of potential response actions are identified and described. The broad array of technologies which may apply to each category are then identified and screened in Section 6.3.2. This preliminary screening procedure has been conducted to identify those technologies that are judged to be applicable to the Site, and which may be potentially effective in meeting the RAOs. Although many of the technologies discussed in Section 6.3.2 are not applicable to the Site, they are presented to document that they were identified and considered. In Section 6.3.3, the potential response actions and technologies retained from the screening process in Section 6.3.2 have been assembled into Removal Action Alternatives. Finally, the Removal Action Alternatives have been analyzed against the criteria of effectiveness, implementability, and cost. A detailed description of this analysis is presented in Attachment D, and a summary of the results of the analysis is presented in Section 7.0.

6.2 Evaluation Criteria

The criteria which are used to analyze Removal Action Alternatives in an EE/CA are defined in the EPA guidance document previously cited. The three general criteria are effectiveness, implementability, and cost. The specific components of each criteria, are defined as follows:

Effectiveness Evaluation

$ Overall protectiveness of human health and environment $ Ability to achieve RAOs/ARARs $ Short-/long-term effectiveness

Implementability Evaluation

$ Technical feasibility $ Administrative feasibility $ Availability of materials and sources $ Community applicability

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Cost Analyses

$ Capital cost $ Post removal control cost $ Present worth cost $ Maintenance and monitoring costs

6.3 Removal Action Alternatives

6.3.1 Description of Broad Categories of Potential Response Actions

The broad categories of potential removal response actions include:

$ No action $ Institutional controls $ Surface Water Control $ Management and/or treatment of waste material

No Action

As a potential response action, “No Action” leaves the contaminated materials at the Site in their current condition and assumes that no further intervention will occur. Although this approach will not actively meet the RAOs for the Site, its consideration and evaluation is required. Other potential response actions will be compared to the baseline provided by “No Action,” under which, no removal activities or monitoring would occur.

Institutional Controls

Institutional controls include administrative land use restrictions, site access restrictions (such as fencing), and/or relocation of potential receptors to attempt to minimize the potential for exposure to site contamination. In general, institutional controls do not actively address site contamination, but attempt to meet the RAOs by reducing the potential for human and ecological exposure to the contaminants. However, these controls do not address the mobility of the contamination or off-site transport of contaminated materials.

Surface Water Control

Surface water runon controls or stormwater management structures include drainage channels, ditches, trenches, or other structures designed to prevent surface water from coming into contact with the contaminated materials. By doing so, erosion of contaminated surfaces and subsequent off-site transport of wastes via the surface water pathway is reduced. However, these controls do not address direct exposure of contaminants to human or ecological targets, nor the off-site transport via other exposure pathways, particularly the air pathway.

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Management and/or Treatment of Waste Material

Management or treatment of the waste material includes options that can be conducted in-situ or ex-situ. Some of the treatment methods do not require movement or handling of the waste material, either on the surface or subsurface. These options include restricting potential exposure by capping, stabilizing the contamination in place, or using innovative technologies to remove the contaminants without physically removing the soil. Potential options which were identified and screened are presented in Section 6.3.2. These include: containment, solidification and stabilization technologies, vitrification, soil washing, soil flushing, thermal treatment, biological treatment, on-site closure, off-site disposal, and installation of stormwater and erosion management structures. Surface water run-on controls or stormwater management structures include drainage channels, ditches, trenches, or other structures designed to prevent surface water from coming into contact with contaminated materials. By doing so, erosion of contaminated surfaces and subsequent off-site transport of contaminants via the surface water pathway is reduced. However, these controls do not address direct exposure of the contaminants to human or ecological targets, nor the off-site transport via other exposure pathways, particularly the air pathway.

6.3.2 Identification and Screening of Management and Treatment Technologies

No Action

The No Action Alternative does not require the employment of any management or treatment technologies.

Site Specific Evaluation: Although this potential Removal Action Alternative will not meet the RAOs, it is used as a baseline against which other alternatives are measured. For this reason, and because a No Action Alternative is required according to EPA guidance, it is retained for further evaluation.

Institutional Controls

Institutional controls are used to restrict access or control use of a site. Institutional controls may include one or more of the following: construction of barriers, installation of fences, gates, moats, warning signs, hostile vegetation, and deed restrictions.

Site Specific Evaluation: Institutional controls at the Site are not expected to be completely effective in meeting the RAOs. Fencing may be partially effective in the short-term to limit trespasser access, but will likely not limit ecological exposure, nor does it address the potential for off-site migration of the contamination. Because of these issues, institutional controls, by themselves, although retained for further analysis of Removal Action Alternatives in Section 6.3.4, are not expected to sufficiently address the RAOs to be selected. However, some of these controls, such as installation of fences, gates, and warning signs are likely to be components of alternatives which involve leaving some or all of the waste material on-site.

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Management and/or Treatment of Waste Material

This section provides a brief description of the management and treatment alternatives for the site waste materials. Based on the site characterization data, the primary contaminants are mercury (distributed over much of the Site) and petroleum hydrocarbons (distributed over a small area adjacent to an aboveground storage tank). Based on the presence of these contaminants, the potential management and treatment alternatives are:

$ Containment $ Solidification/Stabilization Technologies $ Soil Washing $ Soil Flushing $ In-Situ Vitrification $ Thermal Treatment $ Biological Treatment $ Off-Site Disposal $ Surface Water Control

Containment

Containment technologies for application at contaminated sites include landfill covers (caps), vertical barriers such as slurry walls, and horizontal barriers. Capping systems reduce surface water infiltration, control fugitive dust emissions, improve aesthetics, and provide stable surface over the waste. Cap construction costs depend on the number of components in the final cap system. In-situ vertical barriers such as slurry walls constitute an impermeable barrier situated perpendicular to the ground surface and groundwater flow to minimize the movement of contaminated groundwater offsite or limit the flow of uncontaminated groundwater onsite (EPA, 1997).

Containment is most likely to be applicable to: (1) wastes that are low-hazard or immobile; (2) wastes that have been treated to produce low hazard or low mobility waste for on-site disposal; and, (3) wastes whose mobility must be reduced as a temporary measure to mitigate risk until a permanent remedy can be tested and implemented (EPA, 1997). Containment is considered for Site to preclude the need to excavate and move contaminated soil and large amount of mining equipment and structures.

The most important advantages of containment are: (1) surface caps and slurry walls are relatively simple and rapid to implement at low cost and can be more economical than excavation and removal of waste, (2) caps and slurry walls can be applied to large areas or volumes of waste, (3) engineering control is achieved, and may be a final action if metals are well immobilized and potential receptors are distant, and, (4) in some cases it may be possible to create a land surface that can support vegetation and/or be applicable for other purposes (EPA, 1997).

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Disadvantages of containment include: (1) design life is uncertain, (2) contamination remains on-site and is available to migrate should containment fail, (3) long-term inspection, maintenance and monitoring is required; and, (4) the site must be amendable to effective monitoring (EPA, 1997). The site must be suitable for a variety of heavy construction equipment. When capping systems are being utilized, on-site storage areas are often necessary for the materials to be used in the cover. For large jobs, on-site borrow areas are required to make this type of alternative cost effective (EPA, 1997).

This technology can involve the excavation, relocation, and placement of waste material in an engineered on-site repository which is constructed specifically to hold the subject materials. Under this technology, the contaminated materials are excavated from the source and adjacent areas, and transferred to an on-site repository, placed and compacted. The extent of excavation to be performed depends on the removal goals and on the extent to which it is desired that the RAOs and ARARs are to be met. Following placement, the repository containing the waste material is capped, thereby establishing a barrier which eliminates the potential for exposure to human and ecological receptors. Likewise, the potential for off-site transport of the contaminants via the surface water and air pathways will be eliminated. Closure of waste materials in this manner is consistent under EPA guidance (Use of the Area of Contamination Concept During RCRA Cleanups, 1996).

Site Specific Evaluation: Construction of an engineered repository and the subsequent installation of a cap at the Site would involve the consolidation of all contaminated soils and mining wastes (identified as having concentrations of the COCs in excess of removal goals) in a constructed repository. All mining equipment and related debris which is currently located on- site would be placed into the repository as well. The repository would be sized according to the known volumes of material which it is to receive, and constructed in an appropriate on-site location based on a number of factors including slope steepness, location of vegetation requiring clearing, and proximity to the unnamed drainage. Once constructed, the repository would be capped using a combination of on-site and imported materials. Due to the fact that suitable cap material is believed to be readily available in the vicinity, considerable cost savings could be realized under this technology type.

Capping the contaminated soil, mining waste, and mining structures in an engineered repository would limit the potential for human ecological exposure to the contaminants, as well as the potential for off-site migration. Due to climate considerations, the cap would need to be implemented along with meteoric precipitation, stormwater, and erosion management controls to limit the potential for erosion. Although capping would not reduce the toxicity or volume of contamination, it would reduce its mobility by making the contamination inaccessible to stormwater flow. In addition, capping would also limit infiltration and promote runoff away from the contaminated areas, thereby reducing the potential for leaching of contaminants into groundwater. A cap would also serve as a barrier between the mining wastes and potential human or ecological targets. If properly designed, implemented, and maintained, a cap will meet the RAOs by limiting the exposure to contaminants and reducing the potential for migration; therefore this technology is retained for further evaluation.

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Solidification/Stabilization Technologies

Solidification/Stabilization (S/S) are treatment processes that change the physical characteristics of the contaminated material to reduce the mobility of the contaminants by creating a physical barrier to leaching. More specifically, S/S technologies: (1) improve the physical characteristics of the waste by producing a solid from liquid or semiliquid wastes; (2) reduce the contaminant solubility by formation of sorbed species or insoluble precipitates; (3) decrease the exposed surface area across which mass transfer loss of contaminants may occur; and, (4) limit the contact between transport fluids and contaminants by reducing the material’s permeability (EPA, 1997).

S/S technology usually is applied by mixing contaminated soils or treatment residuals with a physical binding agent to form a crystalline, glassy, or polymeric framework surrounding the waste particle. The applicability of the S/S technologies depends on the chemistry of the site specific contaminants and the S/S binders (EPA, 1997). The soil-contaminant-binder equilibrium and kinetics are complicated, and many factors influence metal mobility. The implementation cost is relatively high.

Site Specific Evaluation: If implemented at the Site, this family of technologies will limit the potential for migration to leach to groundwater, but will not reduce the potential for migration due to erosion. In addition, these technologies do not reduce contaminant concentrations on the surface, and therefore will not limit the potential for human or ecological exposure to the contaminants. Most importantly, S/S technologies are high-cost and are not efficient enough to effectively stabilize waste material with high concentrations of mercury. For these reasons, these technologies are not retained for further evaluation.

Soil Washing

Soil washing is an ex-situ remediation technology that uses a combination of physical separation and aqueous-based separation unit operations to reduce contaminant concentrations to site- specific removal goals. The technology detoxifies or significantly alters the contaminants by transferring the contaminant from the soil into the washing fluid or mechanically concentrates the contaminants into a much smaller soil mass for subsequent treatment or disposal. Soil washing is performed on excavated soil and may involve some or all of the following, depending on the contaminant soil matrix characteristics, cleanup goals, and specific process employed: (1) mechanical screening to remove various oversize materials; (2) crushing to reduce applicable oversize to suitable dimensions for treatment; (3) physical processes to liberate weekly bound agglomerates followed by size classification to generate coarse-grained and fine-grained fraction for further treatment; (4) treatment of the coarse-grained soil fraction; (5) treatment of the fine- grained fraction; and, (6) management of the generated residuals (EPA, 1997).

The soil washing process begins with the excavation and preparation of the soil. To separate contaminants from soil, the prepared soil is mixed with water or an amended water-based solution. The soil is then separated from the spent fluid, and is recovered in two fractions. One

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fraction contains larger particles that are clean and can be returned to the ground; the other fraction that usually comprises a much smaller volume carries the bulk of contaminants. The fine soils, in which contaminants have been concentrated, is then treated or disposed in compliance with applicable regulations.

Depending upon site specific conditions, the contaminated washing solution can potentially be recycled or sent to an off-site treatment facility. It is often important to the economic feasibility of the project that the washing solution be recycled. In order to successfully treat this metal- loaded washing solution, the solution should have adequate solubility for the metal so that a smaller volume of washing solution can be used.

The soil washing process generates residual streams that need to be handled properly. These residual streams include non-recyclable metal-bearing particulate; concentrates, soils, and other residuals that typically fail the toxicity characteristic leaching procedure (TCLP) for Resource Conservation and Recovery Act (RCRA) hazardous waste but are also not sufficiently clean to permit return to the site.

Site Specific Evaluation: Treatability studies are typically required to evaluate the potential for success of the soil washing process in removing contaminants to the removal goals as factors such as the physical and chemical characteristics of the soil can be of significant impact to the results. Nevertheless, even without treatability data, it can be reasonably assumed that the removal goals at the Site could be met based on the success of soil washing at similar sites with similar waste materials. However, the costs associated with the mobilization of the highly specialized treatment equipment to a site are not typically justified without a relatively large volume of material to be treated. As such, the treatment costs at the Site will be too high on a per ton basis to merit consideration. For this reason, soil washing is not retained for further evaluation.

Soil Flushing

Soil flushing is the in-situ extraction of contaminants from the soil via an appropriate washing solution in which the flushing fluid, with the site contaminants, is captured from the underlying groundwater by pump-and-treat methods. The technology is applicable to both organic and inorganic contaminants, and metal contaminants in particular. Soil flushing uses water, a solution of chemicals in water, or an organic extractant to recover contaminants from the in-situ material. The contaminants are mobilized by solubilization, formation of emulsions, or a chemical reaction with the flushing solutions (EPA, 1997).

Soil flushing may be easy or difficult to apply, depending on the ability to wet the soil with the flushing solution and to install collection wells or subsurface drains to recover all the applied liquids. The achievable level of treatment varies and depends on the contact of the flushing solution with the contaminants and the appropriateness of the solution for contaminants, and the hydraulic conductivity of the soil. Soil flushing is most applicable to contaminants that are relatively soluble in the extracting fluid, and that will not tend to sorb onto soil as the metal- laden flushing fluids proceeds through the soil to the extraction point.

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Site Specific Evaluation: In-situ soil flushing requires relatively shallow groundwater and simple hydrogeology to expedite capture of the contaminants with extraction wells. Due to the fact that the hydrogeology of the site including depth to groundwater has not been sufficiently studied to date, and due to the expense associated with the installation of the network of extraction wells that would be required, this technology type is not retained for further analysis.

In-Situ Vitrification

This alternative involves passing an electric current through the soil using an array of electrodes inserted vertically into the contaminated region. The soil then begins melting, and provides additional conductance for the current. The melted soil, once allowed to harden after the current sources are removed, has a significantly reduced hydraulic conductivity, thereby stabilizing the contaminants in place. The main requirement for in-situ vitrification (ISV) is the ability of soil to melt, to carry current, and solidify as it cools (Ground-Water Remediation Technologies Analysis Center, 1997). At the sites where soil has high alkali contents, or the soil is dry, enough conductance may not be provided to carry the current, and as a result the ISV will not be successful.

Site Specific Evaluation: ISV is most applicable in sites where contaminated soil contains low levels of mercury and the waste material exists in the subsurface. At sites like the Umpqua AML Site at which waste material with significantly elevated levels of mercury is found above the ground surface, ISV is not a suitable treatment technology. As a result, this technology is not retained for further evaluation.

Biological Treatment

Biological treatment methods are can be used for soils that are contaminated with gasoline, diesel, waste oil, and other heavy hydrocarbon contaminants. High concentration level of contaminants such as metals and other inorganics may limit the applicability and effectiveness of the biological treatments. Under these methods the organic contaminants will be destroyed and converted to stabilized byproducts. The ex-situ biological treatments involves excavating of contaminated soils; mixing the contaminated soil with soil amendments; turning over the contaminated soil to aerate the waste; or combining contaminated soil or sludge with water and other additives to keep solids suspended and microorganisms in contact with soil contaminants. In-situ biological treatments can be implemented in different ways such as mixing the contaminated unsaturated soils with air to stimulate biodegradation; adding oxygen to the waste by turning over or tilling the contaminated soil; using natural attenuation processes to reduce the concentration level of contaminants to acceptable levels; or using plants to clean contamination in soil, groundwater, surface water, sediments, and air. Biological treatment methods are relatively costly when the amount of soil that need to be treated is small.

Site Specific Evaluation: Because the majority of the waste material at the Site is associated with mercury contamination and only small volume of waste material (less than five cubic yards)

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is contaminated with petroleum hydrocarbons, biological treatment processes would unlikely be the appropriate treatment method. Thus, this alternative is not considered for further evaluation.

Thermal Treatment

Under thermal treatment processes, heat is used to increase the separation, decomposition, destruction, or immobilization of contaminants. Thermal desorption and hot gas contamination are used to separate the contaminants, whereas incineration, open burn/open detonation, and pyrolysis are used to destroy contaminants. Hot gas decontamination process involves raising the temperature of the contaminated material for a specified period of time. The gas effluent from the material is treated in an afterburner system to destroy all volatilized contaminants. This method is likely to be used for process equipment requiring decontamination, mine shells to be demilitarized, or scrap material contaminated with explosives. Under the incineration process, high temperatures are used to combust organic constituents in waste. Off gases and combustion residuals generally require subsequent treatment or disposal. Incineration can be used to remediate soils contaminated with volatile heavy metals such as mercury, cadmium, lead, and arsenic, explosives and hazardous wastes, particularly petroleum hydrocarbons and chlorinated hydrocarbons. In open burn (OB) operations, the organic compounds in contaminated soil are destroyed by self-sustained combustion, which is ignited by an external source, such as flame or heat. In open detonation (OD) operations, detonatable explosives are destroyed by the detonation of an energetic charge. Pyrolysis process involves chemical decomposition of organic material by heat in the absence of oxygen. Organic materials are transformed into gaseous components and a solid residue containing fixed carbon and ash. Pyrolysis is most often applicable for semi-volatile compounds and pesticides and may be effective in separating but not destroying the volatile metals. Thermal desorption involves heating the waste to volatilize water and organic compounds. A carrier gas or vacuum system transports volatilized water and organics to the gas treatment system. Thermal desorption process is applicable to volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), volatile metals, polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and pesticides. Thermal desorption process equipment is available skid-mounted and may be transported to sites where large treatment volumes merit the cost of mobilization.

Site Specific Evaluation: As with soil washing, a complete analysis of the effectiveness of thermal treatment requires treatability data. Without this information, however, it is possible to ascertain that thermal desorption would be the most appropriate thermal treatment for the waste materials at the site as it is applicable to both volatile metals like mercury and petroleum compounds. However, the costs associated with the mobilization of the thermal desorption equipment to a site are not typically justified without a relatively large volume of material to be treated. As such, the treatment costs at the Site will be too high on a per ton basis to merit consideration. For this reason, thermal treatment is not retained for further evaluation.

Off-Site Disposal

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This technology involves excavation of the waste materials and subsequent transport off-site to an appropriate disposal facility. Depending upon the specific characteristics of the waste material, appropriate facilities may include existing landfills or other repositories, permitted RCRA Transfer, Storage, and Disposal (TSD) facilities, or in some cases, recycling/salvage facilities. The extent of excavation to be performed depends on the extent to which it is desired that the RAOs and ARARs are met. Unlike alternatives which involve exclusively on-site implementation, no further construction (e.g., capping, installation of surface water diversion structures, implementation of institutional controls) is required outside of the excavation of the materials. However, hauling and disposal costs can often be extremely high, depending upon the proximity of the site to an acceptable disposal facility and the nature of the material requiring disposal. Site Specific Evaluation: There are three main waste streams at the Site: mining wastes that can be characterized as hazardous, mining wastes that are characterized as non-hazardous, and mining related equipment and debris. Each of these waste streams would be handled differently if disposed of at off-site locations in order to minimize the costs for appropriate disposal of the materials. Mining wastes which are characterized as hazardous will require disposal at a TSD facility, but non-hazardous mining wastes are likely acceptable for disposal at a RCRA Subtitle C facility. Mining debris will be assumed contaminated as well (unless demonstrated non- hazardous to the satisfaction of the disposal facility via intensive sampling), and will require encapsulation prior to disposal at a RCRA Subtitle C facility. Despite the relatively high costs associated with this technology, off-site disposal is retained for further evaluation because of the increased level of environmental protection with which it is associated due to the complete removal of all waste material from the Site.

Surface Water Management

Surface water diversion measures are implemented to reduce contaminant mobility by limiting water erosion processes. Stream channel improvements are utilized for many purposes, including relocation or diversion of a stream around potentially contaminated areas. One approach is to use surface water management systems which divert stormwater away from the contaminated areas, and possibly use vegetation or riprap to limit the potential for erosion. This option can be effective in reducing the potential for migration of the contaminants but will not reduce the potential for direct human and/or ecological exposures on-site.

Another approach that may be used is to install structures specifically designed to promote runoff and erosion of the contaminated areas, and to then passively capture the contaminated material in drainage traps. The drainage traps can then be periodically cleaned, and the contaminated material collected for off-site disposal.

Site Specific Evaluation: Site characterization data indicate that there the potential exists for erosion and subsequent downstream transport of the contaminants. However, it is not likely that surface water management alone will be effective in the short- or long-term in meeting RAOs of reducing direct human and ecological exposure to mercury found in the waste material. The waste material at the Site is finely ground and is not in any form of containment, and this facilitates the potential for contact with targets and the potential for continued off-site transport

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via pathways other than surface water. As a result of these considerations, surface water management alone is not considered for further evaluation; however, it may be considered for use as a component of alternatives which involve leaving waste material on-site.

A summary of the results of the screening of management and treatment technologies is presented in Table 6.1.

6.3.3 Assembly of Removal Action Alternatives

The general potential response actions and technologies described in the preceding section have been assembled into four Removal Action Alternatives which have been analyzed with respect to the evaluation criteria. These alternatives have been developed based on the known nature and extent of waste material contamination and results of the human and ecological risk assessments.

$ Alternative 1: No Action $ Alternative 2: Institutional Controls $ Alternative 3: Consolidate Waste Material in an On-Site Repository, Cap, and Revegetate $ Alternative 4: Off-Site Disposal

Alternative 1: No Action

This alternative involves no further action to assess or correct the contamination identified at the site. Retention and analysis of this alternative are required by the NCP.

Effectiveness Evaluation

The No Action Alternative will not be effective in protecting human health or the environment, will not attain ARARs, and will not meet the RAOs. Short and long-term risks to important environmental resources, as well as potential human health risks would continue to exist. No action continues to provide pathways for contaminants to move off-site and affect human or ecological health, particularly through ingestion or inhalation of the contaminated material. Toxicity, mobility and volume of contaminants would not be reduced under the No Action Alternative.

Implementability Evaluation

While it is easily implementable from a technical standpoint, it may not be acceptable to regulators or local residents who are concerned about protection of human health and the environment. Technical and administrative feasibility criteria do not apply to the No Action Alternative.

Costs

There are no direct capital or operating costs associated with this alternative. However, it may provide a future liability cost for the BLM which cannot be estimated.

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Alternative 2: Institutional Controls

This alternative is an on-site effort determined to meet some of the RAOs with a minimal initial capital expense. The primary element of this alternative includes implementation of intensive access controls such as fencing and signage to preclude or minimize access to the waste material, contaminated soils, and mining debris by humans or wildlife.

Because this alternative does not include measures to specifically address the toxicity or volume of the waste material, adequate measures to prevent human or ecological exposure to these materials must be provided. The area of the Site that contains soils and waste materials contaminated with mercury and petroleum hydrocarbons will be fenced, warning signs will be installed, and locked gates will be put into place. The fenced area would encompass all major mining equipment and structures (including the rotary and brick furnace, condenser, ore bins, and collapsed trestle), as well as mining wastes and contaminated soils with mercury concentrations equal to or greater than the camper RMC of 40 ppm. The fenced area would also include the diesel storage tank that contains waste material contaminated with petroleum hydrocarbons.

The major elements of Alternative 2 are shown in Figure 6.1.

Under this alternative an administrative area closure and mineral withdrawal is recommended because the sources remain exposed. A site closure as administered by BLM personnel would help reduce the potential exposure from contact with the contaminants present at the Site. Operations and maintenance under this alternative would consist of minor repair to fences, gates, and signs.

Effectiveness Evaluation

The design concepts comprising this alternative provide a limited level of environmental protection considering the chemical and physical characteristics and the location of the waste material. Due to the close proximity of the Site to a well-traveled access road and the relatively high accessability associated with it, there will be a high residual risk of exposure to humans and wildlife under this alternative since the waste material and mining structures are to remain on- site and exposed. All operations under this alternative are to be conducted on-site; therefore, there will be no potential risks to the public related to the transport of hazardous waste.

The installation of institutional controls at the Site does not meet all of the RAOs. Fencing may be partially effective in the short-term to limit trespasser access, but will likely not limit ecological exposure, nor does it address the potential for off-site migration of the contaminated material. Because soils and waste materials remain in-situ and exposed, ARARs for soil and air quality would not be met by this alternative.

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It is anticipated that there may be several short-term mitigable impacts to the environment during implementation. Impacts could include wildlife disturbance through noise and human activity during construction.

The controls proposed under this alternative do not address the potential for off-site transportation of contaminated soil via surface water run off. Under this alternative, the highly contaminated, finely ground waste material that is primarily present in the partially collapsed main ore bin, fine ore bin, and condenser trough will remain on-site without any form of containment, thus maintaining the potential for transport off-site via surface water runoff. This alternative does not address the volume, toxicity, or accessibility of the waste material. The Institutional Control Alternative seeks to limit on-site exposure to human targets and could be used as a short-term measure until a more comprehensive removal action is taken. Implementability Evaluation

The actions required for the construction of this alternative are technically feasible using standard methods and procedures. The concepts are based on the access control design practices. The necessary equipment, personnel, and services are readily available to support implementation of this alternative. State administrative requirements may be satisfied under this alternative if institutional controls are considered as an interim action.

Cost Analysis

The implementation of institutional controls, and the associated operations and maintenance costs are low when compared to the other alternatives considered during this process (with the exception of the No Action Alternative).

Alternative 3: Consolidate Waste Material in an On-Site Repository, Cap, and Revegetate

Consolidation of soils and waste material in an engineered on-site repository is a comprehensive on-site effort that is more effective than the previous alternatives in meeting the response goals and identified ARARs for the project. Capping and subsequent revegetation of the capped surfaces will stabilize the material and essentially eliminate the volume of waste being washed into the adjacent drainage, thereby eliminating the volume of material leaving the site via the surface water pathway. In addition, the cap will serve as a barrier between site contamination and potential human and ecological receptors.

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The primary elements of this alternative include:

$ Design and construction of a repository in an appropriate on-site location; $ Removal of approximately 520 cubic yards of mercury contaminated soils and mining waste materials from the areas with mercury concentrations above 40 ppm and consolidation within the repository; $ Consolidation, decommissioning, and compaction of the mining structures, equipment, and debris (approximate calculated present volume of 1,050 cubic yards); $ Placement of the decommissioned and compacted mining debris within the repository (approximate calculated compacted volume of 525 cubic yards, assuming an overall compaction ratio of 50 percent); $ Placement of cap materials; $ Revegetation of the cap surface; and, $ Implementation of intensive access controls such as fencing and signage to preclude or minimize disturbance of the repository by humans or wildlife.

The elements which make up this alternative are presented in Figure 6.2.

The following data are used to evaluate this alternative:

$ The XRF results indicating the distribution of mercury contamination in the on-site soil and waste materials; $ The surface area and assumed depth of the on-site contaminated soils and waste materials in excess of the removal goal of 40 ppm; and, $ The approximate observed or estimated dimensions and approximate calculated volume of on-site mining equipment and structures.

A review of the XRF transects (Figure 3.2) and the corresponding XRF results (Table 3.5) indicates that the contaminated soils and waste materials can be divided in two areas, pursuant to the results of the XRF sampling performed by BLM NSTC personnel, and as described in Section 3.1.2; for the purposes of this analysis, these areas will be designated as Areas A and B. Area A has been delineated based on the location of contaminated soils and waste materials with concentrations greater than or equal to 543 ppm. Area B is defined by mercury concentrations between 40 and 543 ppm. Area A, the area of highest mercury concentrations which includes soils, waste material, and mining equipment and structures such as condenser and furnace, is primarily centered over a location which is less than 40 feet from the unnamed drainage. The approximate calculated surface area of soils and waste materials in Area A is 1,770 square feet. Area B has an approximate calculated surface area of 9,200 square feet, and generally encircles Area A . The aboveground storage tank and some mining equipment, such as the grizzly, are located in Area B.

As detailed in Section 3.1.2, the depth of the contaminated material in Areas A and B are approximately two feet and one foot, respectively, and these are the removal depths that are assumed under this alternative. Based on these estimates, approximately 130 cubic yards of contaminated soil will be excavated from Area A and approximately 340 cubic yards will be

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excavated from Area B. Therefore, the total volume of contaminated soil with mercury concentrations in excess of the removal goal of 40 ppm that will be relocated to the constructed repository is approximately 470 cubic yards. Table 6.2 presents the calculated surface area and volume of contaminated soil and waste materials in Areas A and B. In addition to the contaminated soil, approximately 50 cubic yards of mining waste (currently located in the main ore bin, fine ore bin, condenser trough, and condenser shed) will be relocated to the repository. Therefore, the total volume of soil and other waste material, excluding the debris, is approximately 520 cubic yards.

As previously discussed, derelict mining equipment and structures are throughout the Site. Based on the fact that this equipment was used to process materials with high concentrations of mercury throughout the operational life of the Site, it is assumed that the equipment is contaminated enough to make it unacceptable for salvage. For this reason, under this alternative, it is assumed that all debris and equipment presently on-site will be placed into the repository with the contaminated soil. Based on data collected in the field by Dynamac, BLM, and Heritage personnel, the total volume of the on-site mining equipment, structures, and debris have been calculated. These calculations have been performed by examining the approximate observed or estimated dimensions of each piece of equipment. The results of this calculation are presented in Table 6.3. Data from Table 6.3 indicate that the total volume of the on-site mining structures, equipment, and the miscellaneous debris is approximately 1,050 cubic yards. The preliminary cultural assessment of the Site performed by Heritage (Attachment A) indicates that the mining structures and equipment are primarily composed of wood, metal, and brick in varying combinations and at various ratios. Using this information, the total volume of the equipment has been broken down to determine the quantities of each of these materials which will be placed into the repository. These calculations indicate that the equipment/debris component of waste that will be placed into the repository includes approximately 520 cubic yards of wood, 535 cubic yards of metal, and one cubic yard of brick. Prior to placement in the on-site repository, these structures will be compacted (assumed compaction to 50 percent of their original volume) to reduce the volume requiring disposal. After compaction, the estimated volume that will be placed into the repository is approximately 525 cubic yards.

The exact location for placement and construction of the repository is not known at this time; at a minimum, additional survey work, geotechnical testing, and slope stability analyses are recommended to determine the most appropriate location. For the purposes of conceptualizing this alternative, it is assumed that the repository will be constructed approximately 100 feet upgradient from the condenser at a safe distance from the unnamed drainage to prevent erosion impacts to the repository due to flowing surface water. Based on BLM observations, the slope of the hillside at this location is approximately 3:1. Considering that the consolidated soils, waste materials, and compacted debris have the estimated total volume of 1,050 cubic yards, and assuming that consolidated waste in the repository will be placed to an average thickness of seven feet, the approximate surface area of the waste materials will be approximately 4,050 square feet under this scenario.

Potential landfill cover designs for the repository were reviewed and analyzed using the EPA guidance document, Design and Construction RCRA/CERCLA Final Covers (EPA, 1991).

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Although not necessarily legally bound to requirements specified for RCRA covers, EPA guidance suggests that covers to be implemented at CERCLA sites which will cap material classified as hazardous waste (as is the case at the Site) be designed in a manner analogous to RCRA Subtitle C covers unless “site specific design changes have been approved after demonstrating that they meet the intent of the regulations.” Based on these recommendations, the cap design selected for evaluation under this alternative is that of a RCRA Subtitle C cover.

Multi-Layer Cap

Under this capping scenario, the compacted structures and mining equipment will be consolidated and placed as the bottom layer in the repository. Subsequently, this debris will be covered with the contaminated soils and mining waste materials removed from Areas A and B with mercury concentrations in excess of the removal goal of 40 ppm. This configuration was selected in an effort to stabilize the compacted structures and mining equipment, reduce long- term subsidence, and reduce the potential for damage to the cap due to the sharp edges of the compacted debris.

Following placement of the waste material, the cap materials will be placed. A cross section showing the proposed cap construction under Alternative 3 is presented in Figure 6.3.

The components assumed for use in the cover are as follows:

1) The debris, contaminated soil, and other mining waste materials have an average thickness of seven feet; 2) The repository footprint has an approximate surface area of 4,050 square feet; 3) The low hydraulic conductivity layer will be composed of two feet of compacted on-site soil collected from appropriate borrow locations in the soil unit designated 305F (Figures 2.4 and 2.5) and a high density polyethylene (HDPE) geomembrane; 4) The drainage layer and vegetative cover layer will be composed of two feet of compacted on- site soil collected from appropriate borrow locations in the soil unit designated 464G (Figures 2.4 and 2.5); and, 5) The cap surface area will be revegetated.

Soil from the 305F unit was selected for use in the low hydraulic conductivity layer because it is known to have the highest clay content in the vicinity of the Site. According to EPA recommendations, the low hydraulic conductivity layer must be compacted and should have a hydraulic conductivity of no higher than 1 x 10-7 cm/sec. Based on the limited information available, the selected material can be compacted easily, but it is unknown whether or not the target hydraulic conductivity will be met. It is recommended that geotechnical testing be conducted during final cover design to determine final suitability of this material in the low hydraulic conductivity layer; however, for the purposes of evaluating this alternative, it is assumed that this soil will be acceptable. In combination with the HDPE geomembrane, the compacted soil is put in place to prevent moisture from moving downward from the upper layers of the cap and into the waste materials.

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After placement of the geomembrane, a layer of two feet of soil will be placed to serve as a drainage layer and to allow for vegetative growth. Soil from the 464G unit was selected for use in the drainage/vegetative growth layer because of its relatively high gravel content, and because it has been observed as more than adequately supporting local vegetation. As a result of these considerations, it is assumed that no additional topsoil placement or soil amendments will be required under this alternative. Following placement and prior to seeding, the upper layer will be recontoured. Once vegetation is established, it will protect the cap surface from runoff resulting from major storms and will reduce erosion. Based on EPA recommendations, the surface slope should be the same as the underlying soils, with a slope of at least three percent but not greater than five percent.

This combination of layers prevents the majority of percolation by capturing rainwater and allowing lateral drainage and/or evapotranspiration before the water reaches the waste materials. This cap combination also appears as if it will tolerate the anticipated differential settlements due to waste subsidence. Vegetation on the cap surface will offer protection from gulling and scouring by surface water, thereby minimizing the erosion. The cap should be sloped from the center of the containment outward at a minimum of two percent slope to allow for good lateral drainage within the cover section, and to limit erosive velocities of local runoff on the cap. In addition, if erosion matting is not used, then the slope should roughened to prevent erosion from forming.

The percolation volume into the waste materials will be greatly reduced with the implementation of the selected cap system. Under the present site conditions, the contaminated soils, mining waste materials, and debris are highly distributed, often in close vicinity to the unnamed drainage, and are directly exposed to surface water via precipitation. The resulting percolation through the contaminated material supports considerable potential for release of contaminants via surface water and groundwater, but with an engineered cover system to deflect runoff, the risk of release will be greatly reduced.

A system of locked gates and fences should be provided around the perimeter of the repository as a visual deterrent to off-road vehicle use or other activities which may have a negative impact on the cap construction.

Due to the relatively high amount of precipitation typically experienced by the Site and the steep slopes, there is a potential of both differential settlement and slope failure over the life of the cap. As a result, the operation and maintenance activities for this alternative would likely include subsidence and slope failure monitoring. Annual inspection and repair are required for the revegetated cover. These activities would include watering and other care required for the success of the new vegetation, additional placement of seed in areas of unsuccessful revegetation during the initial attempt, and other needed repairs to the surface of the cap.

Following the removal of the soils, waste materials, and debris the excavated areas will be recontoured to the surrounding grade and revegetated. Soils from borrow areas may be used if required.

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Effectiveness Evaluation

The design concepts under this alternative meet the RAOs and provide a the highest level of environmental protection of any potential on-site closure actions by removing the contaminated soils and waste materials from an active drainage to a designed repository. The contaminant mobility at the Site will be reduced by capping the highest risk media sources, primarily contaminated soils and debris. As all operations are to be conducted on-site, potential risks to the public related to the transport of hazardous material will be incidental. It is anticipated that there may be several short-term mitigable impacts to the environment during implementation of this alternative. These impacts may include wildlife disturbance through noise and human activity during construction.

This alternative can effectively reduce the principle threats posed by the release of contaminants of concern from the site by reducing the exposure pathways and the mobility of these contaminants in the air, soil and water. Due to the potential for erosion and differential settlements, a long-term commitment to the operation and maintenance of the repository is be required to achieve the long-term effectiveness of this alternative.

The short-term mitigable impacts to the environment during implementation of this alternative are moderate due to the relatively large volume of materials which will be moved. These impacts may include wildlife disturbance through noise and human activities.

Implementability

Implementation of this alternative involves the use of heavy equipment to compact mining structures and relocate the compacted material to the repository. Removal of soils and waste materials is technically feasible but may be made somewhat difficult by the fact that the most of the contaminated soils, waste materials, and debris are located in a highly vegetated area that is characterized by steep slopes, and which is seasonally is wet. The steep slopes may decrease the speed of removal activities and, consequently, the amount of work accomplished per day. The presence of wet soils and waste materials also may increase the difficulties associated with material handling, and could present challenges to the removal. Conducting excavation work during the dryer months could avoid these challenges. Due to the high density of vegetation in the area, significant clearing and grubbing activities will be required prior to repository construction. Considering that the equipment, personnel, and technology required to construct activities are relatively common, it is anticipated that equipment and staffing would be readily available within close proximity of the Site.

Implementation of this alternative involves construction of the on-site repository in a stable location that is at a safe distance from the unnamed drainage. On-site or local site conditions that may result in increased potential for slope failure and/or differential settling should be considered to determine an appropriate location for repository construction. Field engineering studies should be performed to evaluate the final repository and cap designs, the need for additional access roads for the construction activities, evaluation of potential borrow area soil

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sources, and to verify the effectiveness of the proposed cap. These tasks are all routine geotechnical engineering tasks with proven methods and procedures.

This alternative will satisfy administrative concerns because it effectively eliminates the principle threats posed by the release of the soils and waste materials from the site by isolating them from potential air, soil, and water exposure pathways. It is appropriate from a regulatory standpoint under the EPA “Area of Contamination” (AOC) concept. Under this approach, hazardous waste materials can be consolidated and capped within an AOC without triggering land disposal restrictions (LDRs) or minimum technology requirements. As a result, implementation of Alternative 3 is administratively feasible, since contaminated soils are left on- site and capped, and RCRA LDRs and minimum technology standards are not applicable.

Cost Analysis

The capital costs associated with this alternative are higher than Alternative 2 (Institutional Controls), due to the large amount of labor associated with the design and construction of repository, excavation and consolidation of the waste material in the repository, cap placement, and revegetation. In addition to the capital costs, the operation and maintenance costs in this alternative is higher than two previous alternatives. However, this alternative is expected to be considerably less costly than Alternative 4 (Off-Site Disposal).

Alternative 4: Off-Site Disposal

Off-site disposal of the identified waste materials is a comprehensive effort determined to meet RAOs and ARARs for this project by completely removing the waste source material from the Site, rather than attempting to manage the material in place. Under this alternative, mining waste materials and contaminated soils, and all mining equipment and debris will be removed and disposed in an appropriate off-site disposal facility, so that contaminant sources identified in excess of the removal goals are eliminated.

During the evaluation process for this alternative, consideration was given to decontaminating the derelict process equipment in order to make it suitable for either disposal in a municipal landfill or sale for salvage value. However, it was determined that decontamination of the equipment was not feasible. Suitable decontamination of the debris depends on several factors, such as the degree of penetration of the mercury contamination into the material matrix, the porosity of the material, and the chemical and physical properties of the contaminant which is adhered to the surface to be decontaminated. As outlined during the Alternative 3 discussion, the mining debris at the Site is primarily composed of metal, wood, and brick. Both wood and brick are highly porous materials, and for this reason are likely not suitable for decontamination. Perhaps most significant, the liabilities of making even decontaminated debris available for salvage are not justified by the potential financial advantages with which it is associated. For these reasons, decontamination of the debris prior to subsequent off-site disposal is not considered under this alternative.

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The discussion under this alternative has been divided according to the two types of materials requiring off-site disposal: 1) mining waste and contaminated soil and 2) mining debris and equipment. The mining waste and contaminated soil can be further divided into the following categories: 1) material exceeding the removal goal of 40 ppm of mercury that is characterized as non-hazardous (with TCLP results lower than 0.2 mg/l, corresponding to the assumed total mercury value of 543 ppm as discussed in Section 3.1.2); 2) material exceeding the removal goal of 40 ppm of mercury that is characterized as hazardous (with TCLP results in excess of 0.2 mg/l, corresponding to the assumed total mercury value of 543 ppm as discussed in Section 3.1.2); and 3) soil contaminated with petroleum compounds only. The waste materials have been divided in this manner because each have different disposal requirements, and subsequently, differing disposal costs.

For cost estimating purposes in this EE/CA, it is assumed that all mercury contaminated material, including both characteristically hazardous and non-hazardous soils and all debris, will be transported to a TSD facility that is permitted to accept such materials. Dynamac identified the nearest TSD facility to the Site as Chemical Waste Management (CWM) of the Northwest, Inc., located in Arlington, Oregon. Costs specified under this alternative are based on discussions with and quotes received from CWM.

Disposal volumes for each of the stated waste streams have been calculated using the XRF isocontour map (Figure 3.2) in a manner analogous to the method that was used in Alternative 3. Volume estimates for the mining debris and contaminated soils are presented in Tables 6.3 and 6.4, respectively.

A. On-Site Soils and Mining Waste

As previously indicated, contaminated soils and other mining waste with a mercury concentration greater than the removal goal of 40 ppm will be removed and disposed off-site under this alternative. Volume estimates and disposal details for this material is presented in the sub-paragraphs to follow.

A.1 Mercury Concentration Exceeding 543 ppm.

Contaminated soil and other mining waste with a mercury concentration greater than 543 ppm (corresponding to a TCLP result greater than 0.2 mg/l, resulting in hazardous waste classification) requires treatment by stabilization at a TSD facility prior to ultimate disposal in a RCRA Subtitle C landfill. As a result, the costs associated with disposal of this material is significantly higher than soil removed from the Site which is deemed non-hazardous. According to volume estimates (Table 6.4), approximately 160 cubic yards of material that is to be removed from the Site will fall into this category.

A.2 Mercury Concentration Below 543 ppm.

Contaminated soil and other mining waste with a mercury concentration less than 543 ppm (corresponding to a TCLP result below 0.2 mg/l, resulting in non-hazardous classification) does

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not require treatment prior to disposal in a RCRA Subtitle C landfill. Therefore, the disposal cost per ton is less than the disposal cost for the material discussed in sub-paragraph A.1 above. Based on volume estimates (Table 6.4), approximately 360 cubic yards of material that is to be removed from the Site will fall into this category.

A.3 On-site soils contaminated with petroleum hydrocarbons

Approximately three cubic yards of soil has been identified on-site that are contaminated with petroleum hydrocarbons. Under this alternative, this material will be removed from the area near the aboveground storage tank and will be transferred to the Riverband Landfill (RCRA Subtitle D) in McMinnville, Oregon, approximately 176 miles (3 hours) from the Site.

B. Mining Debris

Under this alternative, it is assumed that the entire volume of mining debris will be disposed off- site at the CWM Westmoreland TSD facility. According to CWM personnel, debris contaminated with mercury may require macroencapsulation treatment prior to final disposal to prevent leaching. CWM requires encapsulation in all cases unless each piece of debris is tested individually and determined clean. Due to the high level of heterogeneity of the large volume of debris present at the Site, the required sampling would be an extremely intensive undertaking if performed. It is entirely likely that much of the debris will require macroencapsulation treatment; therefore, for cost estimating purposes in this EE/CA, it is assumed that no sampling will take place. Rather, it is assumed that the entire volume of debris will require encapsulation prior to disposal.

As detailed in Table 6.3, approximately 1,050 cubic yards of debris are present on-site and require disposal. The disposal volume has been broken down into the three major waste stream components (wood, metal, and brick) in order to more accurately estimate the weight of the material. Based on the available information, the debris is composed of approximately 520 cubic yards of wood, 535 cubic yards of metal, and one cubic yard of bricks. The total weight of each of the three components has been calculated based on reasonable densities obtained for each; based on this calculation, approximately 220 tons of wood, 2,900 tons of metal, and one ton of bricks require disposal.

Following removal of the soils and debris, the disturbed areas will be recontoured to match the surrounding terrain and revegetated, utilizing backfill from appropriate borrow areas, if necessary. For cost estimating purposes, it is assumed that no additional topsoil, borrow material, or soil amendments will be required. The assumed surface area requiring revegetation is approximately 9,100 square feet or 0.21 acres.

The operations and maintenance activities for this option would likely include a six to twelve month period of watering and other care required for the success of the new vegetation and additional placement of seed in areas of unsuccessful revegetation during the initial attempt.

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Effectiveness Evaluation

By removing the entire volume of waste material to an off-site location, the potential for off-site transport of the contaminants is entirely eliminated for all exposure pathways, the potential for exposure to human or ecological targets is eliminated, and the need for long-term maintenance or monitoring is drastically reduced.

The design concepts comprising the this alternative provide the highest possible level of environmental protection considering the chemical and physical characteristics of the mine wastes, and the physical locations of the mining structures, debris, and waste materials. As this alternative proposes transport of the waste material from the Site to another location, there may potential risks to the public related to transport of the hazardous materials.

Removal and off-site disposal of the waste materials will meet all identified ARARs and RAOs for the Site. This alternative would eliminate contaminant mobility by completely removing the highest risk media sources, primarily mercury-contaminated soils and debris, and disposing of these wastes into a permitted off-site disposal facility. Removal of these materials from the drainage area and subsequent treatment or disposal at an appropriate off-site facility reduces the principle threats posed by release to surface water, groundwater, or air in the vicinity of the Site.

Short-term disturbance during the construction activities proposed under this alternative includes impacts from fugitive dust and transportation of waste materials and debris to the selected disposal facilities. Disturbance during constructed is expected to be minimal due to the relative remoteness of the Site. Likewise, the short-term disturbance to ecological receptors is expected to be minimal if proper standard engineering controls are implemented.

Implementability Implementation of this alternative involves the use of heavy equipment which is expected to be readily available. Removal of the contaminated soils from the drainage area is technically feasible but may be made somewhat difficult by the fact that the contaminated soils and waste materials are located in an area that is characterized by dense vegetation, steep slopes, and a seasonally wet climate.

Relatively nearby disposal facilities have been identified which are suitable to accept the soils and debris to be removed under this alternative. This alternative is expected to be administratively feasible; state and community acceptance of this alternative will be determined through the public involvement portion of the BLM community relations effort associated with the EE/CA process.

Cost Analysis

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The capital costs associated with the implementation of this alternative are the highest of the four that have been considered in this EE/CA. Although offering the maximum level of environmental protection, the transportation and disposal costs associated with this alternative present a total cost which is likely unreasonable considering the relative protectiveness and cost for the other alternatives, particularly Alternative 3. Operations and maintenance costs under this alternative are expected to be negligible after the revegetation operations have been determined successful after the first six to twelve months following construction.

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7.0 COMPARATIVE ANALYSIS OF ALTERNATIVES

A comparative analysis of the four Removal Action alternatives with respect to the effectiveness, implementability, and cost criteria is presented in Table 7.1. This chart summarizes the detailed analysis presented in Attachment D. All of the removal action alternatives are expected to be technically implementable. They all involve proven technologies and equipment and services are expected to be readily available.

Alternative 2 (Institutional Controls) is moderately effective in mitigating the human health risk by fencing the area of contamination, but does not prevent ecological exposure, off-site transport of contaminants via the surface water or air pathways, and does not address the volume or toxicity of the contaminants. Since the contaminated soils, waste materials, mining structures, and debris will remain uncovered in this alternative, they remain a threat to human and ecological receptors which come into contact with it (although the fencing will mitigate much of the human health risk), and is still subject to erosion by wind and surface water. Nevertheless, the elements of Alternative 2 are critical parts of Alternative 3 and therefore may be a successful interim measure until funding is available to take further action.

Alternative 3 (Remove Waste Materials to an On-site Repository, Cap, and Revegetate) involves the removal of the contaminated soil, waste materials, and debris and disposal of the material in an engineered on-site repository. Removing the waste materials from the vicinity of the unnamed drainage to a designed repository provides a high level of environmental protection by preventing off-site transport via surface water. Consolidation and capping of the collapsed mining structures and contaminated soil and subsequent placement of institutional controls around the repository will reduce the mobility of mercury in the soil, eliminate air pathways, and serve as a barrier between site contamination and potential human and ecological receptors. This alternative contributes a very high degree of source control and long-term effectiveness. The short-term impacts to the environment during implementation of this alternative may include wildlife disturbance through noise and human activity during construction.

Alternative 4 (Off-Site Disposal) involves the complete removal of the mining structures, debris, the contaminated soils and waste materials and transportation and disposal of the material at an appropriate off-site facility. This alternative completely eliminates the principal threats posed by the release of the contaminated soils and mining structures from the site by isolating them from potential air, soil, and water exposure pathways. Alternative 4 provides the highest level of protection to the environment as well as human health.

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8.0 RECOMMENDED REMOVAL ACTION ALTERNATIVE

As directed by EPA guidance, the four Removal Action Alternatives presented in this EE/CA have been evaluated against the following three general criteria: effectiveness, implementability, and cost. The specific components of each criteria, are defined as follows:

Effectiveness Evaluation

$ Overall protectiveness of human health and environment $ Ability to achieve RAOs/ARARs $ Short-/long-term effectiveness

Implementability Evaluation

$ Technical feasibility $ Administrative feasibility $ Availability of materials and sources $ Community applicability

Cost Analyses

$ Capital cost $ Post removal control cost $ Present worth cost $ Maintenance and monitoring costs

Of the alternatives which have been analyzed, Alternative 3 (Remove Waste Material to an On- Site Repository, Cap, and Revegetate) appears as if it is the most appropriate alternative based on an analysis of these three evaluation criteria. Alternative 3 is effective in complying with ARARs and meeting the RAOs, and is more protective of human health and environment than Alternatives 1 and 2. Although Alternative 4 provides a greater degree of environmental protection, the costs do not appear justified based on the realized increases in environmental protection. Alternative 3 can effectively reduce the principle threats posed by the release of contaminants from the Site by reducing off-site transport via all perceived potential exposure pathways, and significantly reduces the mobility of these contaminants in air, soil, surface water, and groundwater, so as to present benefits in both the short- and long-term. With continued maintenance, this alternative presents adequate long-term benefits, as a properly designed repository with an appropriately designed, constructed, and maintained cap should have a long operational period.

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REFERENCES

Alloway, B.J. ed. 1995. Heavy Metals in Soils, Second Edition. Chapman and Hall, Glasgow, UK.

Bailey, R.G., 1995. Description of Ecoregions of the United States. U.S. Department of Agriculture Forest Service Miscellaneous Publication 1391.

Beyer, W.N., E. Connor, and S. Gerould. 1994. Survey of Soil Ingestion By Wildlife. J. Wildlife Management. Vol. 58.

Brice Environmental Services Corporation, 2001. Personal Communications with Mike Warminsky.

Buonicore, Anthony J. 1995. Cleanup Criteria for Contaminated Soil and Groundwater: ASTM D64. Philadelphia, PA: American Society for Testing and Materials. p. 81-86.

Chemical Waste Management, Inc, 2001. Personal Communication With Mark Krening.

Clear Water Environmental, 2001. Personal Communications With Steve Pearson.

Common Brick Specifications. Standard Series. http://www.australbrick.com.au/bricks/standard.htm

Dynamac Corporation Environmental Services. 1998 BLM RCRA TSD Facility Audit Program, Compilation of Audit Reports.

Evanko, Cynthia, R. 1997. Remediation of Metals-Contaminated Soils and GroundWater, Carnegie Mellon University, Department of Civil and Environmental Engineering, Pittsburg, PA, Technology Evaluation Report, TE-97-01..

Ford, K.L., F.M. Applehans, and R. Ober. 1993. Development of Toxicity Reference Values for Terrestrial Wildlife, Proceedings of the HMC/Superfund '92 Conference, pp 803-812.

Ford, K. L. 1996. Risk Management Criteria for Metals at BLM Mining Sites, Technical Note 390 rev. National Applied Resource Science Center, Denver, CO.

Gilbert, Richard O. 1987. Statistical Methods for Environmental Monitoring. New York, NY: Van Nostrand Reinhold Co. p. 164-185, 204-224.

Heritage Research Associates, Inc., 1999. Preliminary Historical Assessment of the Umpqua Mine, Douglas County Oregon.

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Martin, A.C., H.S. Zim, and A.L. Nelson. 1961. American Wildlife and Plants: A Guide to Wildlife Food Habits. Dover Publications, Inc, New York.

Nagy, K. 1987. Field Metabolic Rate and Food Requirement Scaling 57:111-128.

National Oceanic and Atmospheric Administration (NOAA). 1990. The Potential for Biological Effects of Sediment-Sorbed Contaminants Tested in the National Status and Trends Program. Technical Memorandum NOS OMA 52, Seattle, WA.

O’Brien, James J. 1996. Standard Handbook of Heavy Construction, Third Edition.

O’Fass Environmental, 2001. Personal Communications with John Peterson.

Oregon Climate Service, 1998. Zone 3 Climate Data Archives, Myrtle Creek, OR. (http://www.ocs.orst.edu/allzone/allzone3.html).

Oregon Department of Environmental Quality. Oregon State Administrative Rules, http://www.deq.state.or.us.

Oregon State Revised Statutes, http://landru.leg.state.or.us.

Oregon Department of Environmental Quality. Oregon Disposal Site Permittees, Office of Waste Prevention & Management, http://www.deq.state.or.us.

Perry, Robert and Don Green, 1984. Perry’s Chemical Engineer’s Handbook, Sixth Edition.

Spiegel, Leonard. Reinforced Concrete Design, Third Edition.

U.S. Environmental Protection Agency, 1980, Test Methods for Evaluating Solid Waste, Physical/Chemical Methods,” PB97-156111GEI.

U.S. Environmental Protection Agency, 1986. Quality Criteria for Water. Criteria and Standards Division, Washington, D.C.

U.S. Environmental Protection Agency, 1989. Exposure Factors Handbook. Office of Health and Environmental Assessment. EPA/600/8-89/043.

U.S. Environmental Protection Agency, 1991. Design and Construction of RCRA/CERCLA Final Covers, Office of Research and Development, EPA/625/4-91/025.

U.S. Environmental Protection Agency, 1992. Guidance for Performing Site Inspections Under CERCLA.

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U.S. Environmental Protection Agency, 1993. Guidance on Conducting Non-Time-Critical Removal Actions Under CERCLA, Office of Solid Waste and Emergency Response, EPA540-R- 93-057.

U.S. Environmental Protection Agency, 1993. Wildlife Exposure Factors Handbook. Office of Research and Development. EPA/600/R-93/187a. U.S. Environmental Protection Agency, 1996. Soil Screening Guidance: Technical Background Document, OSWER Directive 9355.4-17A.

U.S. Environmental Protection Agency, 1996. Use of the Area of Contamination Concept During RCRA Cleanups.

U.S. Environmental Protection Agency, 1997. Mercury Study Report to Congress, Vol. VI: An Ecological Assessment for Anthropogenic Mercury Emissions in the United States. EPA-452/R- 97-008.

U.S. Environmental Protection Agency, 1997. Best Management Practices for Soils Treatment Technologies, Office of soild Waste and Emergency Response, EPA530-R-97-007

U.S. Environmental Protection Agency, 1997. Technology Alternatives for the Remediation of Soils Contaminated With As, Cd, Cr, Hg, and Pb, EPA/540/S-97/500.

U.S. Environmental Protection Agency, 1999. Guidelines Establishing Test Procedures for Analysis of Pollutants; Measurement of Mercury in Water (EPA Method 1631, Revision B); Final Rule.

U.S. Geological Survey, 1973. Deadman Mountain, Oregon, 7.5 Minute Series Topographic Quadrangle.

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Table 2.1- Soil Unit Properties

Soil Unit Composition Profile Drainage Class Permeability Available Water Capacity

464G Klickitat Gravelly Loam Well Drained Moderate About 5.5 inches

Harrington Gravelly Loam Well Drained Moderately Rapid About 3.0 inches

305F Honeygrove Gravelly Clay Loam Well Drained Moderately Slow About 9.0 inches

Source: Preliminary Cultural Assessment of the Umpqua Mine, Douglas County, Oregon, Heritage Research Associates, Inc., 1999.

Table 3.11 - Surface Water Sampling Analytical Results (General Water Quality Parameters)

Parameter Units Detection OR OR OR OR/EPA UMS-SW-6 Limit WQC WQC WQC MCL 4/SMCL5 FWA 1 FWC 2 W & FT 3

Total mg/L 10 NE 20 NE NE 330 Alkalinity

Bicarbonate mg/L 10 NE NE NE NE 330 Alkalinity

Carbonate mg/L 10 NE NE NE NE ND Alkalinity

Hydroxide mg/L 10 NE NE NE NE ND Alkalinity

Chloride mg/L 2 860 230 NE 250 170

Nitrate mg/L 0.2 NE NE 10 10 ND

Nitrite mg/L 0.05 NE NE NE 1 ND

pH SU NE NE NE NE 7.12

Sulfate mg/L 100 NE NE NE 500 7.5

TDS mg/L 40 NE NE NE 500 630

Total mg/L 0.02 0.022 0.0052 0.2 0.2 ND Cyanide

1 - Oregon Water Quality Criteria - Fresh Water Acute 2 - Oregon Water Quality Criteria - Fresh Water Chronic 3 - Oregon Water Quality Criteria - Water & Fish Ingestion 4 - Maximum Contaminant Level 5 - Secondary Maximum Contaminant Level ND - Not Detected; samples were analyzed for this compound but it was not detected NE - Not Established Numbers in Bold indicate that the value shown exceeds one or more regulatory or risk-based threshold. TDS - Total Dissolved Solids

Table 3.11 - Sediment Sampling Analytical Results

Sample Number Mercury Concentration (mg/kg) Dilution Factor

UMS-SED-1 (Deadman Creek Downgradient) 1.7 10

UMS-SED-2 (Deadman Creek Upgradient/Background) ND 1

UMS-SED-3 (Stanley Creek Downgradient) 8.2 20

UMS-SED-4 (Unnamed Mine Drainage) 8.0 20

UMS-SED-5 (Stanley Creek Background) 0.38 1

UMS-SED-6 (Adit Flow) ND 1

ND - Not Detected Table 3.1 - Waste Source and Soil Sampling Summary

Sample Sample Location Date Time Number Type

UMS-SBG-1 Soil Sample collected upgradient from the site near an old logging road 10/19/99 1045 to determine the concentration of mercury in native soil which was not impacted by the mining activities.

UMS-WS-1 Waste Sample collected from one of the small tailings piles at the north 10/19/99 0919 material end of the site (Feature F.17) to determine the concentration of mercury in the material.

UMS-S-2 Waste Sample collected adjacent to the above-ground storage tank (F.8.4) 10/19/99 0929 material to identify the tar-like substance.

UMS-WS-3 Waste Sample collected from a pile of finely ground material adjacent to 10/19/99 0935 material the “hopper” or main ore bin (F.8.2) to determine the concentration of mercury in the material.

UMS-WS-4 Waste Sample collected from pile of finely ground material found in the 10/19/99 1001 material trough adjacent to the condenser (F.8) to determine the concentration of mercury material, and to determine the amount of mercury leaching from the material during precipitation events.

UMS-WS-5 Waste Sample collected in a depression just north of the collapsed 10/19/99 1008 material condenser shed (F.8.8), which appears to act as a “sink” for the accumulation of sediments, to determine the concentration of mercury in the material.

UMS-WS-6 Waste Sample collected from finely ground material still contained in the 10/19/99 1012 material remains of the collapsed fine ore bin (F.8.7) to determine the concentration of mercury in the material.

UMS-WS-7 Waste Sample collected from finely ground material found in the 10/19/99 1025 material “hopper” or main ore bin (F.8.2) to determine the concentration of mercury material, and to determine the amount of mercury leaching from the material during precipitation events.

UMS-S-8 Waste Sample collected from unnamed mine drainage sidewall south of 10/19/99 1037 material/soil BLM Road 29-2-26.0 to determine concentration of mercury in material near main tunnel (F.16) to determine if contamination is present due to stockpiling of material near the adit during mining.

Table 3.2 - Approximate Volumes of Waste Units

Waste Unit Approximate Volume (cy)

Condenser (F.8) Trough 2

Fine Ore Bin (F.8.7) and Condenser Shed (F.8.9) 25

Main Ore Bin or “Hopper”(F.8.2) 20

Tailings Pile (F.9) 10

Tailings Pile (F.15) 8

Tailings Pile (F.17) 15

Tar-like Substance in Above Ground Storage Tank 3 and Associated Contaminated Soil cy - cubic yards

Table 3.3 - Waste Source and Soil Sampling Analytical Results (Mercury)

Mercury Concentration SPLP Result Sample Number (mg/kg) Dilution Factor (mg/l)

UMS-SBG-1 0.53 1 ND

UMS-WS-1 (tailings) 1.1 5 N/A

UMS-WS-3 (hopper/main ore 110 200 N/A bin)

UMS-WS-4 (condenser trough) 760 1000 0.28

UMS-WS-5 (depression) 900 1000 N/A

UMS-WS-6 (fine ore bin) 60 200 N/A

UMS-WS-7 250 1000 ND

UMS-S-8 4.9 10 N/A

Notes: EPA SSL for Mercury (inhalation) = 10 milligrams per kilogram (mg/kg). EPA SSL for Mercury (ingestion) = 23 mg/kg. BLM HRMC for Mercury in Soil (camper value) = 40 mg/kg. ND = Not detected. N/A = Not applicable (not tested). Bold indicates that the value exceeds one or more of the applicable thresholds.

Table 3.4 - Waste Source and Soil Sampling TCLP Analytical Results (Mercury)

Sample Number TCLP Result Dilution Factor Total Mercury (mg/L) Concentration (mg/kg)

UMS-TCLP-1 0.021 10 140

UMS-TCLP-2 ND 1 1.2

UMS-TCLP-3 0.0057 1 730

UMS-TCLP-4 ND 0.54 1

UMS-TCLP-5 ND 8.0 1

Notes: EPA SSL for Mercury (inhalation) = 10 miligrams per kilogram (mg/kg). EPA SSL for Mercury (ingestion) = 23 mg/kg. BLM HRMC for Mercury in soil (camper value) = 40 mg/kg. TCLP Hazardous Waste Threshold = 0.2 mg/l. ND - Not Detected mg/L - miligram/Liter Bold indicates that the value exceeds one or more of the applicable thresholds.

Table 3.5 - XRF Analytical Results (mg/kg)

Number Sample Date/Time Pb As Hg Zn Cu Ni Fe Mn Cr Detection Limit 20 20 25 40 70 100 280 220 220 540 BLANK 11/16/2000 12:28

Table 3.6 - Waste Source Sampling Analytical Results (TPH-DRO)

Analyte Concentration (mg/kg)

Diesel 6900

Oil 32000

C10 - C32 38900

Table 3.7 - Surface Water and Sediment Sampling Summary

Sample Sample Location Date Time Number Type

UMS-SW-1 Surface Sample collected from Deadman Creek, approximately 30 feet downgradient of 10/19/99 1106 Water the confluence with Stanley Creek to determine the dissolved concentration of mercury in the surface water of the creek after it receives water from Stanley Creek, and hence, from the unnamed mine drainage.

UMS-SED-1 Sediment Sample collected from Deadman Creek, approximately 30 feet downgradient of 10/19/99 1106 the confluence with Stanley Creek to determine the concentration of mercury in an area which may be receiving sediments washed downstream from the site.

UMS-SW-2 Surface Sample collected from Deadman Creek, approximately 20 feet upgradient of the 10/19/99 1123 Water confluence with Stanley Creek to establish the background dissolved concentration of mercury in the stream prior to any contribution from the site.

UMS-SED-2 Sediment Sample collected from Deadman Creek, approximately 20 feet upgradient of the 10/19/99 1123 confluence with Stanley Creek to establish the background concentration of mercury in the sediments of the stream prior to any contribution from the site.

UMS-SW-3 Surface Sample collected from Stanley Creek, between the confluences with the unnamed 10/19/99 1146 Water mine drainage and with Deadman Creek to determine the dissolved concentration of mercury in the Stanley Creek following the contribution of waters impacted by the site.

UMS-SED-3 Sediment Sample collected from Stanley Creek, between the confluences with the unnamed 10/19/99 1146 mine drainage and with Deadman Creek to determine the concentration of mercury in the sediments of Stanley Creek in an area which may be receiving sediments washed downstream from the site.

UMS-SW-4 Surface Sample collected from the unnamed mine drainage just north of the condenser 10/19/99 1218 Water (F.8), waste chute (F.8.11), and other mining equipment on site to determine the dissolved mercury concentrations in the surface water found in the drainage just after leaving the site boundary.

UMS-SED-4 Sediment Sample collected from the unnamed mine drainage just north of the condenser 10/19/99 1218 (F.8), waste chute (F.8.11), and other mining equipment on site to determine the concentration of mercury in the sediments found in the drainage just downstream of the site boundary which may be washing downstream and impacting other locations.

UMS-SW-5 Surface Sample collected from Stanley Creek just upstream of BLM Road 29-2-26.0 to the 10/19/99 1250 Water southwest of the site to establish the background dissolved concentration of mercury in the stream prior to any contribution from the site.

UMS-SED-5 Sediment Sample collected from Stanley Creek just upstream of BLM Road 29-2-26.0 to the 10/19/99 1250 southwest of the site to establish the background concentration of mercury in the sediments of the stream prior to any contribution from the site.

UMS-SW-6 Surface Sample collected from the water flowing out of the adit or “main tunnel” (F.16) to 10/19/99 1300 Water determine the dissolved concentrations of mercury which this water may be contributing to the unnamed mine drainage. This water was also sampled for anions, total dissolved solids (TDS), pH, and alkalinity.

UMS-SED-6 Sediment Sample collected at to the adit or “main tunnel” (F.16) opening to determine the 10/19/99 1300 concentration of mercury in the sediments at this location, which may be washing downstream and impacting other locations on and off the site.

Table 3.8 - 1999 General Water Quality Parameters Field Measurements

Sample Number Flow pH Temperature Conductivity (μS) (gpm) (C)

UMS-SW-1 (Deadman Creek Downgradient) 15 6.9 5.6 159

UMS-SW-2 (Deadman Creek 15 6.9 5.3 137 Upgradient/Background)

UMS-SW-3 (Stanley Creek Downgradient) 5 7.6 8.1 812

UMS-SW-4 (Unnamed Mine Drainage) 2 7.8 8.7 852

UMS-SW-5 (Stanley Creek Background) 3 7.4 8.4 156

UMS-SW-6 (Adit Flow) 1 6.6 9.2 945 gpm - gallon per minute

Table 3.9 - Surface Water Results and Regulatory and Risk Based Thresholds for Mercury in Water

Sample 1999 5/2000 6/2000 Regulatory Concentration (ng/l) (ng/l) (ng/l) Threshold/ (ng/l) Criteria

UMS-SW-1 (Deadman Creek ND 6.12 1.93 Oregon WQC - 2400 Downgradient) Fresh Water Acute (FWA)

UMS-SW-2 (Deadman Creek ND 6.5 2.43 Oregon WQC - 12 Upgradient/Background) Fresh Water Chronic (FWC)

UMS-SW-3 (Stanley Creek ND 20.5 14.9 Oregon WQC - 144 Downgradient) Water and Fish Ingestion (W&FI)

UMS-SW-4 (Unnamed Mine ND 1900 244 EPA/Oregon 2000 Drainage) Drinking Water MCL

UMS-SW-5 (Stanley Creek ND 5.58 3.42 BLM Surface Water 93 Background) HRMC (camper value)

UMS-SW-6 (Adit Flow) ND 10.6 10.4 ng/l - nanogram/Liter ND - Not Detected

Table 4.1 - Umpqua Mine Comparison of Analytical Results and Risk Management Criteria Mine Waste Results (mg/kg or ppm) and Surface Water (ng/l)

Mine Waste (ppm)

ANALYTE 3E Elk RMC Camper RMC

Antimony NA NA 50

Arsenic

Cadmium NA 3 70

Copper

Lead 40 127 1000

Mercury 1488+++ 11 40

Nickel

Selenium

Silver NA NA 700

Zinc 130 275 40000

Surface Water (ng/l)

ANALYTE UMS-SW-4 OR-FWC OR-MCL

Mercury 1,900+++ 12 2 ,000

NA - Not Applicable ppm - parts per million ng/l - nano gram/liter Table 5.1 - Summary of Potential Chemical-Specific ARARs

Potentially Standard, Requirement, Potentially Relevant and To Be Criteria, or Limitation Citation Applicable Appropriate Considered Description/Comments

National Primary and 40 CFR Part 141 and No No No Health-based standards (MCLs) for public Secondary Drinking 143 drinking water systems. Groundwater is not Water Standards part of any proposed removal alternatives.

Oregon Primary OAR 340.041 No No No Health-based standards (MCLs) for public Drinking Water drinking water systems. Groundwater is not Standards part of any proposed removal alternatives.

RCRA Groundwater 40 CFR No No No Sets standards for groundwater at RCRA Protection Standards 264.92-264.101 facilities. Ground water is not part of any proposed removal alternatives

Federal Water Quality 40 CFR Part 131 Yes Sets standards for surface water to protect Criteria Quality Criteria for aquatic organisms and human health. Water, 1986

Oregon Water Quality OAR 340.041.0001- Yes Sets standards and classifications for Oregon Standards OAR 340.041.0975 State waters.

Oregon Groundwater OAR 340.040.0001- Sets standards and classifications for Oregon Quality Protection OAR 340.040.0210 State ground waters. Program

Clean Air Act, National 40 CFR Part 50 Yes Sets standards for air emissions. Primary and Secondary Ambient Air Quality Standards

Oregon Water Pollution ORS 468B.005-ORS Yes State of Oregon Water Pollution control statutes. Control Regulations 468B.190

Oregon Standards for ORS Ch. 517.952- No No No Regulations governing design, construction, Mining Operations ORS Ch. 517.989 operation and closure of mining operations.

National Emission 40 CFR Part 61, Yes Regulates emission of hazardous chemicals to Table 5.1 - Summary of Potential Chemical-Specific ARARs

Potentially Standard, Requirement, Potentially Relevant and To Be Criteria, or Limitation Citation Applicable Appropriate Considered Description/Comments Standards for Subparts N, O, P, the atmosphere. Hazardous Air Pollutants

Oregon Emission OAR 340.244 Yes Same as above. Standards for Hazardous Air Pollutants

Oregon Air Pollution ORS 468A.005-ORS Yes Regulations governing air pollution control, Control Regulations 468A.085 including surface disturbance and relating permitting activities, such as emission control from stationary generators.

Toxic Substances 40 CFR,Part 700 No No No Regulates hazardous materials from manufacture Control Act to disposal. Applies to manufacturers and processors.

BLM Risk Management Technical Note 390 Yes Suggests acceptable multimedia criteria for Criteria rev. heavy metals as they relate to recreational use and wildlife habitat on BLM lands.

Interim Guidance on EPA Directive Yes Suggests levels for lead in soil. This factor Establishing Soil Lead #9355.4-02, would be considered if lead is found in elevated Cleanup Levels at September, 1989 levels in soils remaining after contaminant Superfund Sites removal.

Table 5.2 - Summary of Potential Action-Specific ARARs

Potentially Standard, Requirement, Potentially Relevant and To Be Criteria, or Limitation Citation Applicable Appropriate Considered Description/Comments

Oregon Mined Land OAR Division 30 Yes Yes Regulates the reclamation of all mined land Reclamation Rules 632.030.0025- within the State of Nevada. 632.030.0035

RCRA Subtitle C 40 CFR Part Yes Yes Regulates disposal of hazardous materials. 261.4(b)(7) and Applicable for disposal of listed wastes and RCRA Section sludges. Relevant and appropriate for disposal 3001(b) (Beville of hazardous mine waste. Amendment)

Solid Waste Disposal 40 CFR Part 257, Yes Regulates the storage and handling of solid Act as amended by the Subpart A: § waste. Resource Conservation 257.1-1 Floodplains, and Recovery Act of paragraph (a); § 1976 (RCRA) 257.3-7 Air, paragraph (b)

Oregon Statutes on OAR 125.30, 125.85, Yes Regulates the storage and handling of solid Solid Waste Disposal 840.12-840.97, waste and Recycling 845.20 ORS Ch. 459-459a

Oregon Hazardous OAR 340.100 - OAR Yes Regulates the storage and handling of hazardous Waste Regulations 340.135 waste

Hazardous Materials 49 USC § Yes Regulates the transportation of hazardous waste. Transportation Act 1801-1813 40 CFR 107, 171-177

Table 5.2 - Summary of Potential Action-Specific ARARs

Potentially Standard, Requirement, Potentially Relevant and To Be Criteria, or Limitation Citation Applicable Appropriate Considered Description/Comments Guidelines for the Land 40 CFR Part 241, Yes Regulates the land disposal of solid waste. Disposal of Solid pursuant to 42 USC Wastes § 6901, et.seq.

Guidelines for the 40 CFR Part 243, Yes Establishes guidelines for the collection of Storage and Collection pursuant to 42 USC residential, commercial, and institutional solid of Residential, § 6901, et.seq. waste. Commercial, and Institutional Solid Waste

Source Separation for 40 CFR Part 246, Yes Outlines requirements and recommended Materials Recovery pursuant to 42 USC procedures for source separation of solid waste. Guidelines § 6901, et.seq.

Guidelines for 40 CFR Part 256, Yes Establishes guidelines for Federal approval of Development and State solid waste management programs. Implementation of State Solid Waste Management Plans

Criteria for 40 CFR Part 257, Yes Establishes criteria for solid waste disposal Classification of Solid facilities and solid waste management. Waste Disposal Facilities and Practices

Identification and 40 CFR Part 261, Yes Establishes the procedures and process for Listing of Hazardous listing and determining hazardous waste. Waste

Table 5.2 - Summary of Potential Action-Specific ARARs

Potentially Standard, Requirement, Potentially Relevant and To Be Criteria, or Limitation Citation Applicable Appropriate Considered Description/Comments Standards Applicable to 40 CFR Part 262, Yes Establishes standards for the generation of Generation of hazardous waste. Hazardous Waste

Standards Applicable to 40 CFR Part 263, Yes Regulates the transportation of hazardous waste. Transporters of Will apply only if hazardous materials are Hazardous Waste transported off site.

Standards for Owners 40 CFR Part 264, Yes General regulations for the design, operation, and Operators of pursuant to 42 USC and maintenance of hazardous waste treatment, Hazardous Waste § 6924, 6925 storage, and disposal (TSD) facilities. Treatment, Storage, and Disposal Facilities

Interim Standards for 40 CFR Part 265 Yes Establishes standard for TSD facilities during Owners and Operators State: 6 CCR 1007-3 interim status. of Hazardous Waste Part 265 Treatment, Storage, and Disposal Facilities

Standards for the 40 CFR Part 266 No No No Establishes requirements for the recovery of Management of precious metals from a waste stream. Does not Specific Hazardous apply to mined land reclamation. Wastes and Specific Types of Hazardous Waste Management Facilities

Interim Standards for 40 CFR Part 267 Yes Establishes requirements for new hazardous Owners and Operators waste land disposal facilities. Table 5.2 - Summary of Potential Action-Specific ARARs

Potentially Standard, Requirement, Potentially Relevant and To Be Criteria, or Limitation Citation Applicable Appropriate Considered Description/Comments of New Hazardous Waste Land Disposal Facilities

Hazardous Waste 40 CFR Part 270 No No No Establishes procedures for obtaining U.S. EPA Permit Program permit for hazardous waste management program. Permits are not required for on site disposal of mining waste.

National Pollutant 40 CFR Parts 122, Yes Regulates the discharge of treated effluent and Discharge Elimination 125, storm water runoff to waters of the U.S. System

Effluent Limitations 40 CFR Part 440, Yes Sets standards for discharge of treated effluent pursuant to 33 USC to waters of the U.S. § 1311 State: 5 CCR 1002-3, §§ 10.1 to 10.1.7, pursuant to CRS § 25-8-503

Toxic Pollutant 40 CFR Part 129, Yes Establishes standards or sets prohibitions for Effluent Standards pursuant to 33 USC certain hazardous constituents. § 1317

Occupational Safety 29 USC §§ 651-678 Yes Regulates worker health and safety. and Health Act

Federal Mine Safety 30 USC §§ 801-962 Yes Regulates worker safety at active mine sites. and Health Act

Table 5.2 - Summary of Potential Action-Specific ARARs

Potentially Standard, Requirement, Potentially Relevant and To Be Criteria, or Limitation Citation Applicable Appropriate Considered Description/Comments Hazardous Materials 49 USC §§ Yes Regulates the transportation of hazardous Transportation Act, 1801-1813 materials. D.O.T. Hazardous 49 CFR Parts 107, Materials 171-177 Transportation Regulations

Discharged Petroleum OAR 340.108, Yes Regulates cleanup of oil and other hazardous Cleanup Regulations OAR material spills and releases. 340.047.0005-OAR 340.047.0240

Oregon Cleanup Rules OAR 340.122.0205- Yes Regulations governing hydrocarbon for Leaking Petroleum OAR 340.122.0360 contaminated soils or groundwater. Hazardous Waste Oregon DEQ personnel indicated that there are no AST rules for the state but that the UST rules should be used.

Contaminated Sites ORS 465.200- Yes Regulations governing action levels for Action Levels ORS 465.510, contaminated sites. Regulations ORS 465.900, OAR 340.122.0010- OAR 340.122.0590

Water Control OAR Yes Regulations and statutes governing water Regulations 340.045.0005-OAR pollution control permits, and general storm 340.045.0080 water permits.

Table 5.2 - Summary of Potential Action-Specific ARARs

Table 5.3 - Summary of Potential Location-Specific ARARs

Potentially Standard, Requirement, Potentially Relevant and To Be Criteria, or Limitation Citation Applicable Appropriate Considered Description/Comments

National Historic 16 USC § 470 et seq. A Yes Regulates impacts to historic Preservation Act (NHPA) portion of 40 CFR § 6.301 places and structures. (b), 30 CFR Part 63, Part 65, Part 800

Oregon Register of Historic Yes Review of potential impacts to Places historic places and structures.

The Historic and 40 CFR § 6.301(c) Yes Protects sites with archeological Archaeological Data significance. Preservation Act of 1974

Historic Sites Act of 1935, 40 CFR § 6.301(a) Yes Regulates designation and Executive Order 11593 protection of historic places.

The Archaeological Yes Regulates removal of Resources Protection Act of archeological resources from 1979 public or tribal lands.

Oregon Historical, and ORS 358, ORS 390, OAR Yes Regulations for historic and Archaeological Resources Ch. 736 Div 50 & 51 archeological resources on State Rules and Regulations lands.

Executive Order No. 11990 40 CFR § 6.302(a) and Yes Minimizes impacts to wetlands. Protection of Wetlands Appendix A

Executive Order No. 11988 40 CFR § 6.302 and Yes Regulates construction in Floodplain Management Appendix A floodplains.

Section 404, Clean Water 33 CFR Part 330 Yes Regulates discharge of dredge or Act (CWA) fill materials into water of the U.S.

Fish and Wildlife 40 CFR § 6.302(g) Yes Requires coordination with Coordination Act Federal and State agencies to Table 5.3 - Summary of Potential Location-Specific ARARs

Potentially Standard, Requirement, Potentially Relevant and To Be Criteria, or Limitation Citation Applicable Appropriate Considered Description/Comments provide protection of fish and wildlife.

Endangered Species Act 50 CFR Parts 17, 402 Yes Regulates the protection of 40 CFR § 6.302(b) threatened or endangered species.

Oregon Department of OAR 603.073.0001- Yes Maintains a listing of threatened Agriculture's Division of Natural OAR 603.073.0110 and endangered plant populations Resources, Plant Conservation Biology Program

Oregon Endangered Species OAR 635.100.100- Yes Protection of indigenous species Rule OAR 635.100.135 of animals in the State of Oregon.

Wilderness Act 50 CFR 53, 50 CFR 27 No No No Limits activities within areas designated as wilderness or National wildlife refuge. The Site is not in a designated wilderness or National wildlife refuge.

Oregon State Police Yes Protects wildlife from Wildlife Enforcement and detrimental actions. Penalties

Wild and Scenic Rivers Act 40 CFR § 6.302(e) No No No Establishes requirements to 36 CFR Part 297 protect wild, scenic, or recreational rivers.

Table 6.2 - Approximate Volume and Weight of Contaminated Soil and Mining Waste

Soils Contaminated With Mercury Surface Area (sq ft) Excavation Elev (ft)1 Volume (cu ft) Volume (cy) Area A2 1770 2 3540 131 Area B3 9200 1 9200 341 Total 12740 472 Soils Contaminated With Petroleum Hydrocarbons Volume (cu ft) Volume (cy) 81 3 Mining Waste Volume (cu ft) Volume (cy) 1270 47

Notes: 1- It is assumed that soils in Area A will be excavated within 2 feet, and soils in Area B will be excavated within 1 feet. 2- Area A: Contaminated soil and waste material in this area contains mercury with a concentration exceeding 543 ppm. 3- Area B: Contaminated soil and waste material in this area contains mercury with a concentration between 40 and 543 ppm. 4- Estimated weight for on site soils is calculated by using the density of gravelly loam soil and the volume. The majority of on-site soil is gravelly loam. Density of gravelly loam: 2941.5 lb/cy (Source: Standard Handbook of Heavy Construction, James J. O'Brien, 3rd Edition) sq ft - square feet - ft - feet cu ft - cubic feet cy - cubic yards lb - pounds Table 6.3 - Approximate Dimensions, Volume, and Weight of Debris

Structure Composition Width (ft) Length (ft) Height (ft) Rotary Furnace (F.8.8) 100% Metal 3 30 5 Condenser Shed (F.8.9) 100% Wood 12 25 12 Conveyor (F.8.6) 90% Metal 10% Wood 3 40 30 Rotary Grizzly (F.8.3) 100% Metal 14 17 12 Fine Ore Bin (F.8.7) 85% Wood 11 17 12 15% Metal Condenser (F.8) 10% Wood 14 20 20 90% Metal Main Ore Bin (F.8.2) 85% Wood 17 17 30 15% Metal Brick Furnace (F.10) 100% Brick 9 11 3 Flume (F.11) 50% Wood 3 11 3 50% Metal Waste Chute (F.8.11) 95% Metal 6 9 6 5% Brick Retort (F.7) 100% Metal 5 3 14 Diesel Fuel Tank 100% Metal 4 13 6 Misc1 75% Metal 25% Wood Total Volume (cu ft) Total Volume (cy) Total Weight Total Weight (lb) Total Weight (ton)

Notes: 1- Miscelleneous items include but not limited to collapsed trestle, above ground storage tank, and discarded diesel engine. 2- Unit Weight of Wood = 35 lb/cu ft (Source: Reinforced Concrete Design, Leonard Spiegel, 3rd Edition) 3- Density of Metal = 442 lb/cu ft (Source: Perry's Handbook of Chemical Engineering, Robert H. Perry, Sixth Edition) 4- Density of Brick= 99.88 lb/cu ft (Source: Common Brick Specifications - Standrad Series, http://www.australbrick.com.au) 5- Assume that each brick has the weight of 3.0 kg (Source: Common brick Specifications - Standard Series, http://www.australbrick.com.au cu ft - cubic feet ft - feet cy - cubic yards lb - pounds Table 6.3 - Approximate Dimensions, Volume, and Weight of Debris

Volume (cu ft) Wood (cu ft) Metal (cu ft) Brick (cu ft) Number of Bricks 450 450 3600 3600 3240 3600 360 2856 2856 2339 1988 351 5600 560 5040 8670 7370 1301 120 99 50 50 324 308 16.2 210 210 302 302 405 304 101 29000 14000 15000 16 1050 520 535 1 Wood2 Metal3 Brick4 Brick5 490000 6500000 1600 800 250 3000 1 1

1- Miscelleneous items include but not limited to collapsed trestle, above ground storage tank, and discarded diesel engine. 35 lb/cu ft (Source: Reinforced Concrete Design, Leonard Spiegel, 3rd Edition) 3- Density of Metal = 442 lb/cu ft (Source: Perry's Handbook of Chemical Engineering, Robert H. Perry, Sixth Edition) 4- Density of Brick= 99.88 lb/cu ft (Source: Common Brick Specifications - Standrad Series, http://www.australbrick.com.au) 5- Assume that each brick has the weight of 3.0 kg (Source: Common brick Specifications - Standard Series, http://www.australbrick.com.au

Table 6.4 - Approximate Volumes of Hazardous and Non-Hazardous Wastes

Waste Type Waste Soil Total Total Total Volume Volume Volume(cy) Weight1 Weight (cy) (cy) (lb) (ton)

Non-Hazardous (>40 ppm and <543 ppm) 20 341 361 1,100,000 499

Hazardous ( >543 ppm) 27 131 158 470,000 213

Notes: 1- The mining waste and soil are gravelly loam. Density of gravelly loam is 2941.5 lb/cy (Source: Standard Handbook of Heavy Construction, James J. O’Brien, 3rd Edition) cy - Cubic Yards ppm - Parts Per Million Table 6.1 – Summary of Screening of Management and Treatment Technologies

Category Management/Treatment Technology Results of Screening Process

No Action None Retained for further analysis

Institutional Controls Barriers Eliminated Fences, gates, warning signs Retained for further analysis

In-situ Horizontal Barriers Eliminated Management and/or In-situ Vertical Barriers Eliminated Treatment of Waste Material In-situ Capping Eliminated

Solidification/Stabilization Eliminated

Vitrification Eliminated

Soil Washing Eliminated

Soil Flushing Eliminated

Removal to an On-Site Repository Retained for further analysis

Removal to an Off-Site Repository Retained for further analysis

Surface Water Diversion Eliminated Diversion Channels and Trenches

Table 7.1 - Comparative Analysis of Removal Action Alternatives

Alternative 1: Alternative 2: Institutional Alternative 4: Off-Site Disposal Alternative 3: Consolidate Waste No Action Controls Criteria Materials in an On-Site Repository, Cap, and Revegetate

Effectiveness

Overall Effectiveness 4 3 2 1

Protection of Human Health   • •

Protection of Environment   • •

Compliance with ARARs   • •

Long-Term Effectiveness   • •

Short-Term Effectiveness  •  •

Toxicity, Mobility, Volume Reduction   • •

Implementability

Overall Implementability 1 2 3 4

Technical Feasibility • • • •

Administrative Feasibility   • •

Availability of Services & Materials • • • •

Community Acceptability    

Cost

Capital Cost $0 $3,393 $180,854 $850,252

Operations and Maintenance Cost $0 $1,280 $5,500 $1,000 • Completely Meets Criteria  Partially Meets Criteria  Does not Meet Criteria  Community Acceptability to be determined Through Public Comment