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Union Pacific Railroad Company 

## Work Plan Harrison Street Slag Pile Closure Intersection ofHarrison and Monroe Streets Leadville, Colorado
November 12, 1998

Submitted to: United States EPA Region VIII 999 18th Street Denver, Colorado 80203
Prepared for: Union Pacific Railroad Company 1416 Dodge Street Omaha, Nebraska 68179

Environmental Resources Management 5950 South Willow Drive, Suite 200 Greenwood Village, Colorado 80111

(303) 741-5050

ERM.TABLE OF CONTENTS

1.0 INTRODUCTION 1.1 PURPOSE 1.2 PROJECT BACKGROUND 2.0 SITEHISTORY 2.1 SITE DESCRIPTION 3.0 SUMMARY OFPREVIOUS INVESTIGATIONS 4.0 SCOPE OFWORK 5.0 REFERENCES
LIST OFAPPENDICES AppendixA Example Deed Restriction1.0 INTRODUCTION

Denverand Rio Grand West Railroad (D&RGW) has relocated the lead slag pile formerly located at the Northeast cornerof the intersection of Harrison Street and Monroe Street in Leadville, CO. The Harrison Street (HS) slag pile has been consolidated onto the Arkansas Valley (AV) slag pile. The United States Environmental Protection Agency (EPA) has determined that a cover layerof fill material must be placed over the location ofthe former HS slag pile before clean-up is considered complete and D&RGWs responsibility pursuant to the Consent Decree between D&RGW and the United States have concluded with respect to the Harrison Street property. D&RGW has developed this Work Plan to describe the field work necessary to complete the project.

1.1 PURPOSE

The HS Slag pile is part of D&RGWs Operable Unit 3 (OU3) responsibilities forthe California Gulch Superfund Site pursuantto its Consent Decree with the United States. OU3 includes the HS slag pile, the AV slag pile, the La Plata slag pile, and D&RGWs rail easement and railyard in the town of Leadville. By relocating the slag pile and providing a workplan forthe completion ofclosure activities, D&RGW is in compliance with the Consent Decree for remediation ofthe HS Slag pile area ofOU3.

1.2 PROJECTBACKGROUND

UPRR subcontracted ERM Rocky Mountain to relocate the HS slag pile. The project took place from September of 1997 through March of 1998, during which approximately 104,000 CY ofslag was moved to the Arkansas Valley Slag Pile (AV). A Record of Decision (ROD) issued by EPA in May of 1998 has selected a No Action Alternative for the stockpiled fines (less than 3/8" diameter) atthe AV slag pile. Section 2.0 provides a description of the site and its history. Section 3.0 provides a summary of the previous investigation work. Section 4.0 describes the scope of workforthe completion of activities and presents the project schedule.

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The California Gulch Superfund Site (which encompasses the town of Leadville, Colorado as well as surrounding areas) is located approximately 100 miles southwest of Denver, CO, at an elevation of 10,000 feet mean sea level. The area has experienced 130 years of mining and smelting activities. It was placed on the National Priorities list in 1983 due to extensive drainage of acid-metal laden water into the Arkansas River. Throughoutthe area, silver, gold, copper, lead and zinc were mined by underground and placer methods from majorsulfide and carbonate ore deposits. To extract metals from lead ore, the ore was fed to a blast or reverberatoryfurnace (smelter) where the metals were removed as oxidized vapors. One byproduct of these processes is lead slag. Slag is a darkvitreous material that is composed primarily of iron, magnesium, calcium, and silica, with residual heavy metals. Slag is hard and relatively dense and generally exists as lava-like rock layers or blocky and angular material generallyfound very nearthe smelterareas. As many as 17 smelterfacilities have been reported to have operated in the California Gulch area. Although smelting operations no longerexist in Leadville, slag piles can still be seen throughout the mining district. The D&RGW owns three slag piles (i.e., Arkansas Valley, La Plata, and Harrison Street) associated with the California Gulch site. The HS slag pile was purchased from NL Industries in 1983, and the AV pile was purchased from ASARCO in 1961. The history ofthe slag pile started when Harrison Reduction Works (HRW) began operations as a carbonate ore smelting facility within Leadville city limits in 1877. The location ofthe smelterwas on the Northeast corner of Harrison Avenue and Elm Street. By 1883, the HRW smelter installed roasting furnaces to process sulfide ores. In 1887, a double elevatorwas installed to increase the height ofthe slag pile outside the facility. The HRW smelterclosed in 1893 during the silver panic. (MK, 1992) During the next century the production ofore from local mines decreased dramatically, and an attempt was made to rework many ofthe old slag piles left by the smelters. In 1917, Harrison Recovery Works was established to reworkthe HS slag pile, which was estimated to be greater than 1 million tons at the time. (MK, 1992) The HS slag pile was purchased by D&RGW in 1983 for use as ballast production. The original slag pile ranged from 20 - 50 feet in height, and covered an area of approximately 3 acres. Only small traces (concrete

ENVIRONMENTAL RESOURCES MANAGEMENT. 2 P:\1000\UNIONPAC\CALGULCmWPLN-HS2;DOCand a few bricks) were left from the smelting facility atthe north side ofthe pile. (MK, 1992) Today, the pile and all traces ofthe smelting facility are gone. The HS slag pile consolidation onto the Arkansas Valley slag pile was completed in March 1998. The site work will be complete with the installation ofa cover layeras described in Section 4.0.

SITE DESCRIPTION The former HS slag pile is located at the northeast cornerof Harrison and Monroe. Starr Ditch runs along the south side ofthe former pile, and a gas station and several small houses are located immediatelyto the north. Additional residences are located approximately 200 yards to the east, and commercial buildings and the Apache Tailings Ponds are located 200 yards to the south. The climate ofthe area is typical ofthe mountain regions in central Colorado. The temperature extremes range from 86 °F to -30°F with the average daily minimum temperature being 21.9 °F. The wind is generally out ofthe northeast, with gusts of0 - 30 miles per hour.

ENVIRONMENTAL RESOURCES MANAGEMENT. 3 P:\10O0VUNIONPAC\CALGULCH\WPLN-HS2.DOCSUMMARY OF PREVIOUSINVESTIGATIONS

State ofColorado Remedial Investigation. 1986 Atthe time ofthis Rl, the State did not consider slag to be a significant source ofcontamination, and the slag piles were not studied during this investigation. EPA Phase II Remedial Investigation. 1989 EPA contracted CH2MHNI to sample the surface water, ground water, and many mine waste piles in the area in 1986. The HS slag pile was one of the lead slag piles sampled in this study. Samples were analyzed for metals composition with the following procedures: x-rayfluorescence instrumentation, Extraction Procedure Toxicity Leaching Characteristics (EPTOX), and ASTM acid and watershake extractable metals tests, The results indicated that the HS slag pile (and also the La Plata slag pile) exceeded the RCRA criteria for lead. Morrison Knudsen (previous contractorfor D&RGW) has implied that these results are unreliable due to overly conservative testing procedures, lack of representative data, cross-contamination of samples in the field, and improperly performed sample collection and testing. James P. Walsh and Associates. Inc. Soils Investigation. 1988 Walsh performed an investigation for ASARCO to determine potential action levels for soil, the background concentrations of metals in the soil, and the extent and possible sources ofsoil contamination. Three slag piles, including the HS slag pile, were sampled during this investigation. Morrison Knudsen does not report the findings ofthis study, and disputes the validity ofthe results due to a lack of methodology and quality control information presented. Jacobs Engineering Slag Sampling. 1989 EPA retained the services of Jacobs Engineering to determine the concentration of metals, migration potential, and potential health and environmental hazards associated with the three slag piles owned by D&RGW (including the HS slag pile). Four locations were sampled atthe HS street pile, andi were analyzed for 23 target analyte test metals. Leachabilitywas also analyzed using EP toxicity tests, and ASTM acid and water shake tests. The results indicated that metal concentrations remained belowthe RCRA standards. However, the EPA performed five additional EP toxicity tests without the knowledge of Jacobs Engineering or D&GRW. Three ofthe five EPAtest results exceeded the RCRA standards for lead. Morrison Knudsen disputes the validity of these tests

ENVIRONMENTAL RESOURCES MANAGEMENT. 4 PUOOO\UNIONPAC\CALGULCH\WPLN-HS2.DOCdue to unrepresentative samples, lack ofquality control information presented, and overly conservative testing procedures. Morrison Knudsen Lead Slag Pile Remedial Investigation. 1992 Morrison Knudsen (MK) performed a remedial investigation of the lead slag piles in the California Gulch Site for D&RGW in 1991 and 1992, underAdministrative Order on Consent CERCLA-Vlll-92006. The purpose ofthe study was to determine the potential Impacts of the slag piles on human health and the environment. The potential release mechanisms evaluated were: leaching, wind erosion, runoff, and mixing by human activities. During the reconnaissance, MK examined the structural features ofthe slag piles, including bedding and layering, fractures and cracks,joint block boundaries, and slope stability. The piles were surveyed and mapped, and the volume ofeach pile was calculated. The volume ofthe HS slag pile was determined to be 104,400 CY. Six surface samples (0-3 feet) and three subslag samples (11 - 47 feet) were taken from the HS slag pile. Results indicated that the HS pile had relatively high concentrations ofcalcium, iron, magnesium, manganese, and lead, The subslag area ranged in depth from 0.5 -10 feet deep and consisted of fill overlying a thin layerofclayey silt and gravel-sand mixture. Concentrations ofthe four metals ofconcern in the three subslag samples are shown in the following table: Sample Arsenic (mg/kg) Cadmium (mg/kg) Lead (mg/kg) Zinc (mg/kg) HRB101T10 27.90 <0.40 794 1290 HRB102T10 19.10 <0.40 290 504 HRB103T20 <4.00 10.00 212 647
Subslag samples were collected from the other piles in the California Gulch Site as well, but the concentrations of cadmium, lead, and zinc in the subslag at the Harrison Street pile were the highest. The natural soil beneath boring HR103 has a lead concentration of212 mg/kg, and it has been indicated that the soils beneath all ofthe slag piles have metals concentrations similarto background values. The study determined that the only viable release mechanism forthe lead slag piles in the California Gulch Site was leaching of metals through contactwith precipitation or othersite waters.

ENVIRONMENTAL RESOURCES MANAGEMENT. 5 P:\1000\UNIONPAC\CALGULCH\WPLN-HS2.DOCSite-Wide Screening Feasibility Study (SFS). 1993 The SFS completed in March of 1993 was ajoint effort between the Potentially Responsible Parties (PRPs) and EPA. The purpose ofthe SFS was to screen several remediation alternatives for, among otherthings, slag located at the AV slag pile based on the following criteria: overall protection of human health and the environment, compliance with Applicable or Relevant and Appropriate Requirements (ARARs), long term effectiveness and permanence, reduction oftoxicity, mobility and volume, shortterm effectiveness, implementability, cost, state acceptance, and community acceptance. The three alternatives retained for further evaluation were: no action, institutional controls, and resource utilization. EPA Baseline Human Health RiskAssessment. 1995 b, c After identifying the primary chemicals of potential concern at the site to be lead and arsenic, the risk assessmentfocused on potential risks to residents and recreational users and workers. In all scenarios, it was determined that exposure pathways were most likely insignificant, except in the case of resource utilization ofthe fine slag, which could result in the release of particulates. However, dust spraying and appropriate surface water managementwould limit exposure during possible resource utilization activities. EPA Baseline Aquatic Ecological Risk Assessment. 1995 d

EPA Ecological Risk Assessmentfor the Terrestrial Ecosystem. 1997 EPA determined that risks to aquatic and terrestrial ecosystems were insignificant due to the lack of migration pathways for metals ofconcern and the absence ofviable habitats and sustenance in the slag piles. D&RGW Feasibility Study ofStockpiled Fine Slaa. 1996 This feasibility studyfocused oh the stockpiled fine slag at the AV slag pile, and the three potential remediation alternatives retained from the SFS. The alternative recommended was the no action plan. EPA Record of Decision for Stockpiled Fine Slag in the Arkansas Vallev Smelter Slag Pile. 1998 The ROD released in 1998 concurred with the results ofthe D&RGW Feasibility Study of 1996 and recommended a no action plan for stockpiled fines in the AV slag pile. The ROD also included an option of resource utilization dependent on the future marketvalue ofthe fine slag, ENVIRONMENTALRESOURCESMANAGEMENT. 6 P:\ 10QOUJNIONPACtCALGULCH\WPLN-HS2.DOCwhich will have to be encapsulated before possible use as fill orconcrete aggregate. The ROD stated that a no action plan was protective of human health and the environment because no complete exposure pathways (including leaching of metals through contactwith precipitation or other site waters) exist.

ENVIRONMENTAL.RESOURCES MANAGEMENT. 7 P:\1000\UNIONPAC\CALGULCH\WPLN-HS2.DOCSCOPE OF WORK

The scope of workfor this project involves application of a soil cover over the area ofthe former HS slag pile. The area ofthe slag pile will be mapped, and coverwill be applied to a depth ofat least six inches. The area is estimated to be approximately 250,000 ft2 and will require approximately 5100 yd3 ofsoil forthe cover. Visual inspection and documentation will be conducted to ensure that adequate depth ofcover is applied. Alternatively, asphalt may be used as cover instead of soil. The property may be graded prior to covering if necessary forthe intended future use of the site. Ifasphalt is used, it will be applied to a thickness of at leastfour inches. Visual inspection and documentation will verify that appropriate grading and paving methods have been sufficiently completed. The property may be sold to anotherowner fordevelopment. Ifthe property is sold, completion of this workplan will be included as a condition ofthe sale. Sale ofthe property prior to capping will allow a new ownerto grade the propertyfor final use. The cap can then be applied following grading. A Deed Restriction similar to the document provided as AppendixA will be included as part of any property transaction. Completion ofthe cover installation and cover inspection will be documented in a photo log. The photo log and inspection measurements shall be submitted to EPA as part of a final verification report forthe Harrison Street Slag Pile Closure.

ENVIRONMENTAL RESOURCES MANAGEMENT. 8 P:\1000\UNIONPAC\CALGULCH\WPLN-HS2.DOCREFERENCES

MK (Morrison Knudsen) 1992, Final Report forLead Slag Pile Remedial Investigation atthe California Gulch Site, Volume 1, Leadville, Colorado. Prepared by Morrison Knudsen Corporation for Denver & Rio Grand Western Railroad Company, December 11, 1992. EPA 1998. Record of Decision: Stockpiled Fine Slag, Arkansas Valley Smelter Slag Pile, California gulch Superfund Site (Operable Unit 3), Leadville, Colorado. May 1998.

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## Appendix A Example Deed Restriction

### DEED RESTRICTION

Thefollowing property was formerly thelocation ofaslag pile associated with metal miningand smelting. Slag is ahardlava-like materialcomposedprimarily ofiron, magnesium, calcium, silica andresidualheavy metals. The slagpilewas removedfrom theproperty; however, some slagremainsbelow grade. The property wasincluded as part ofthe CaliforniaGulch Superfund Site OperableUnit 3. Theparcel is located at the northeastcomer ofHarrison and Monroe inthe city ofLeadville, Colorado. Specifically, theparcel is locatedin the Southwest QuarterofSection 24 andtheNorthwest Quarterof Section 25, Township 9 South, Range 80 West. (See AttachedDrawing) Basedon thepresence ofbelowgrade slag andelevated concentrations oflead in soil at thisproperty, EPAhas required thatafinal coverbeplaced overthenative soils onthis property. Thepurpose ofthecoveris to reduce thepotential"forcontactandexposure to slag and soils with high concentrations oflead. AFinal WorkPlan forthe Harrison StreetSlag Pile Closurehas beenfiled withthe United StatesEPA RegionVIII. The WorkPlan requiresthat afinal coverbeplaced overthe site. Thecover willconsistof one ofthe following:

• aminimum ofsix inches ofsoil, • aminimum offour inches ofasphalt, or • acombination ofasphaltfor someportions oftheproperty andsoil forotherportions. Thefinal covershall beinspected as specified inthefinal workplan. Upon completion ofthework, disturbanceofthe cover shouldbe avoided. TheUS EPAshould be contactedby theownerpriorto anyexcavation or subsurface workwhich may disturbthe site. Upon completion ofanyfuture subsurface work, thecovershould berestored bythe currentowner oftheproperty.

# I

424.8 69.7'

UNION PACIFIC | SCALE: I" = 200'

0 100 200 400 ALL DISTANCES ARE APPROXIMATE SALE AREA SHOWN
--- SPTCO. R/W OUTLINED

CADD FILENAME SCAN FILENAME I58l-38.dgn

ATTACHED NOTE:BEFORE YOU BEGIN ANY WORK, SEE AGREEMENT FOR FIBER OPTIC PROVISIONS.

EXHIBIT 'A' 80DTHEISN PACIFIC T3AMSPCg3AT3GM COMPAQ

LEADVILLE.LAKE COUNTY.COLORADO OPP. M.P. 275.5 - MAIN LINE (D. & R.G.W.)

PROPOSED CONVEYANCE SCALE: I" = 20C REAL ESTATE DEPAF OMAHA,NEBRASKA DAI

RLH FILE: 1581-38 DRG20173619