Five-Year Review Report

Five-Year Review Reportfor

Eagle Mine Superfund SiteEagle County, Colorado

September 2000

Prepared By:

REGION VIIIUNITED STATES ENVIRONMENTAL PROTECTION AGENCY

DENVER, COLORADO

CONTENTS

EPA Five-year Review ReportAppendix A - MapsAppendix B - Soils/Metals MapsAppendix C - Sources Used

Viacom Five-year Review Report

Photographs

1

UNITED STATES ENVIRONMENTAL PROTECTION AGENCYREGION 8

999 18th STREET - SUITE 500DENVER, CO 80202-2466

http://www.epa.gov/region08

EAGLE MINE SUPERFUND SITE - FIVE-YEAR REVIEW

Introduction

Federal statue requires that the Environmental Protection Agency (EPA) conduct what istermed a “five-year review” at all Superfund sites where “remedial actions have resulted in anyhazardous substances, pollutants, or contaminants remaining at the site above levels that allow forunlimited use and unrestricted exposure.” Although controlled, wastes do remain at the Eagle MineSuperfund site (Site) near Minturn, Colorado, above these levels. The following report is the firstfive-year review for the Site. This review was conducted in cooperation with the Colorado Departmentof Public Health and Environment (State).

Attached to this EPA review is a document entitled “Five Year Review Report - Eagle MineSite - Minturn, Colorado.” This report was prepared by Dames & Moore, technical consultants toViacom, successor to a former owner and the responsible party at the Site.

Actual cleanup of the Site began in 1988 under the terms of a Consent Decree between theState and Gulf + Western, Inc.. This Consent Decree will be called the “Original Consent Decree” inthis report. Major elements of the cleanup, including the consolidation and capping of surface wastesand the addition of a water treatment plant, were agreed to in this decree. EPA became more involvedin the project in 1990. This involvement resulted in additional clean up measures being added to thosein the Original Consent Decree. These additional cleanup measures were agreed to in a separatethree-party Consent Decree signed by EPA, the State, and Viacom in 1996. This three-party ConsentDecree will be called the “Three-party Consent Decree” in this review.

The cleanup measures described in the Original Consent Decree and the Three-party ConsentDecree will be discussed in this review. The attachment prepared by Dames & Moore, however, onlydescribes those activities undertaken under the Three-party Consent Decree. It should also be notedthat all the components of the work under the completed Original Consent Decree have been describedin Construction Completion Reports as required by that first decree. These completion reports havebeen reviewed and approved by the State.

EPA has divided the Site into what are known as Operable Units. Operable Unit One (OU-1)encompasses the bulk of the remedial effort conducted to date. Operable Unit Two (OU-2), the onlyother operable unit at the Site, encompasses the Townsite of Gilman. OU-2 basically deals withprocedures that will be followed if, and when, the town-site may be redeveloped.

2

Though no redevelopment has taken place in Gilman at this time, this five-year review will also include adiscussion of OU-2.

Background

Five-year reviews are to be conducted within five years after the signing of a Record OfDecision (ROD) on a Superfund cleanup, and at five year increments, thereafter, as long as anypollutants remain on-site above levels that allow for unlimited use and unrestricted exposure. Eventhough materials have been removed, isolated, or safely controlled, wastes remain on the site abovethese levels. This first five-year review of the Eagle Mine cleanup is undertaken, therefore, to answerthe basic question of whether the remedial measures performed by Viacom are protective of publichealth and the environment.

The Original Consent Decree, and its attached Remedial Action Plan (RAP), included thefollowing major cleanup components: (1) placing bulkheads in Eagle Mine adits (plugging the mine); (2)moving and consolidation of Old Tailings Pile (OTP) wastes and Roaster Pile wastes at the existingNew Tailings Pile (this repository thus became known as the Consolidated Tailings Pile, or the CTP);(3) covering the OTP area with clean soil; (4) contouring the CTP and covering it with a protective cap;(5) reclaiming the OTP, Rex Flats, Roaster Pile, and the CTP areas, and; (4) diverting water aroundcertain of the waste rock piles located in the Gilman/Eagle Mine area. The original plan also called forcollecting and pumping ground water from the New Tailings Pile back into the mine through the existingslurry line. The Original Consent Decree was later amended to include the addition of a mine seepcollection system and a water treatment plant located on the CTP. This treatment plant, along with asludge dewatering system, treats water from the mine seeps and ground water collected fromunderground trenches located on two sides of the CTP.

In 1990, EPA became aware that there was a need to address certain issues that had arisenwith the original cleanup. At this time, it began an additional study, called the Feasibility StudyAddendum (FSA), that analyzed the need for additional cleanup measures. The FSA was completed in1992. This document led to the publication of an EPA Record Of Decision (ROD) in 1993 that calledfor additional cleanup. Viacom agreed to implement many of the provisions described in the FSA andthe additional cleanup effort was formalized in the Three-party Consent Decree, finalized in 1996.

The new decree contained the following additional provisions: (1) established additional criteriafor determining revegetation success; (2) required diversion of clean ground water around the CTP; (3)required diversion of clean Rock Creek water around the mine waste and seep areas; (4) required thecollection, for treatment, of Rock Creek ground water; (5) required cleanup and rehabilitation of theMaloit Park wetlands; (6) required further evaluation of the waste rock piles; (7) required continuedpumping, and treating of CTP ground water; and (8) established a process for developing a biologicalbased water quality standard for the river.

3

During the FSA process an extensive human health risk assessment was made of the MaloitPark wetlands and Minturn Middle School areas. Also, in this time period, Viacom agreed to constructtwo new Town of Minturn drinking water wells, located above any possible influence by the CTPground water. Along with the additional work agreed to in the new Three-party Consent Decree, theeffort under the Original Consent Decree continued.

The major problem with the Eagle River and certain of its tributaries, along with site groundwater, has been with elevated metals levels. These metals include zinc, cadmium, iron, and others. Thereader should note, however, that in most of the following discussion about water quality trends, thediscussion is based on dissolved zinc levels. Zinc is used because it not only has had a significant impacton the river’s biological resources but is also the major pollutant at the Site. In addition, an evaluationconducted early in the cleanup revealed that there was a relationship between levels of zinc and theother metals in terms of relative quantity. In other words, if zinc values went down, or up, the othermetals did likewise, and in a generally similar manner. Zinc was determined to be the “indicator” metalat that time. Elevated levels of other metals, especially cadmium, have also had a significant impact onthe river but this review will focus on dissolved zinc levels.

Zinc levels are discussed throughout this report in the dissolved form, although zinc load values(total zinc) are also offered in some of the discussion. Though total zinc loads are quantified in theregular reporting that is done on this project, the river biota are mostly impacted by zinc in the dissolvedform. Also, water quality values for March are used throughout most of the report because this month isgenerally the period of lowest flow in the river. Thus, this period represents generally the worse casemonth in terms of metals concentrations (the concentrations are greatly diluted once spring snowmeltgets underway). In addition, the Eagle River, along with its major tributaries in the Eagle Mine area,have been sampled and records kept for March metals concentrations since the project began. Thisextensive record allows an evaluation of metals trends for a full ten-year period. A map showing EagleRiver, and tributary water quality sampling station locations, is found in Appendix A. A map of theentire Site, with site features, is also found in Appendix A.

The following discussion is organized as follows. First, it will first describe each component ofthe cleanup separately. Second, it then summarizes the results of the various activities as they havecumulatively affected the dissolved metals levels in the Eagle River. Last, a section on public healthaspects of the Site is included at the end of the discussion, as well as a list of certain recommendationsfor future activities at the Site.

4

FIVE-YEAR REVIEW OF OPERABLE UNIT ONE

Individual Components

Eagle Mine Workings

The Eagle Mine workings are comprised of an estimated 70 miles of tunnel. The mine workingsthemselves have been flooded by the discontinuance of mine dewatering, in 1984, and subsequentplugging (bulkheading) of a number of the tunnel openings (adits) that lead into the undergroundworkings. There is an estimated 700 million gallons of water held behind these bulkheads. The conceptbehind the flooding was to make a passive treatment system out of the mine by excluding atmosphericoxygen from the sulfide ore body and slow the formation of acid mine drainage.

This concept, which has been implemented at other underground mines, was to deny oxygen tothe chemical process (by flooding the ore bodies) which leads to the generation of acid and subsequentdissolution of metals. Though the mine was always expected to discharge some water, it was hoped thiswater would be low in dissolved metals and acceptable for release to the river. There is evidence thatthis concept has worked to some extent as the dissolved metals concentrations have decreasedsignificantly over the last eight years. For example, at seepage station S-5, dissolved zinc values havedropped from 130 mg/l in April, 1991, to 38.0 mg/l in April, 1999. The same trend can be seen inmeasurements taken at seep station S-7 with dissolved zinc values falling from 180 mg/l in April, 1992,to 34.0 mg/l in April, 1999. Little variation has been found in the mine pool zinc values through thecalendar year.

As will be discussed in subsequent paragraphs, the metals load attributable to the mine hasdecreased since remediation began. Though it is difficult to calculate, some of this decrease canprobably be attributed to the fact that the water leaking from the mine contains lower metalsconcentrations than before the remediation began.

The major problem with the flooded mine has been that, unfortunately, once the water levelsrose to a certain height in the plugged mine workings, the water came into contact with the Bleakhouseworkings, which connect to more fractured rock which is intercepted by Rock Creek. Contaminatedmine water then began to exit the mine via these fractures. Seeps developed in the Rock Creekdrainage, north of the main mine workings, and began discharging contaminated water. Two other oldmines which lie directly south of the Eagle Mine workings, the Tip Top, and the Ben Butler, also beganto discharge mine water at this time. While not physically connected to the Eagle Mine via tunnel, thesetwo mines were assumed to be hydraulically connected in some way to the flooded Eagle Mine.

Following these developments, the State and Viacom made several major modifications to theirOriginal Consent Decree. First, Viacom agreed to install a water treatment plant and a seep collectionsystem in Rock Creek. This system was designed to collect and treat the mine

5

discharge. It also agreed to collect and treat the discharge from the Ben Butler and Tip Top mines.Viacom agreed to construct and operate this water treatment plant and seep collection system in 1990.

Because of the severity of the mine discharge situation, and the need to quickly address thisproblem, a “package” water treatment plant was first installed. However, this system did not function aswell as intended and was subsequently replaced in 1991 with a much more efficient customized plant.This treatment system, along with the collection system, has now been in-place and functioning foralmost ten years. Though this system requires continuing maintenance, it has functioned quite well andhas made a significant improvement in lowering the level of dissolved metals in the Eagle River. Onecontinuing maintenance problem has been with keeping the pipe open that brings the seep water to thetreatment plant. Another problem has been with handling the large volume of water the plant has to dealwith during the spring high flow period.

Overall, though, the treatment plant has been efficiently operated and in compliance with itsColorado discharge permit. It should be noted that the State-issued discharge permit for the treatmentsystem is set on an in-stream water quality standard for zinc that may be changed in the future. Whetherthis possible change would require modifying the treatment plant has not been determined.

In addition to treating the mine seep water and water discharged from the mine as part of themine draw down operation (MDD), the water treatment plant also treats ground water collected fromunder the CTP. In 1998, the water treatment plant treated 168.8 million gallons of water. Some 9% ofthe water that was treated came from the mine seeps, 78% came from the MDD operation, and 13%was collected for treatment from the CTP ground water collection system.

One of the most significant aspects of the seep collection/treatment system has been thatViacom has been able to pump the water level in the mine down below what is thought to be the mainfracture zone through which the mine water escapes to surface in the Rock Creek drainage. This hashad the direct effect of drying up several of the former seeps. In 1998, because of this lowering of themine pool, there were only 5 seeps with enough flow that could be sampled.

In 1999, Viacom added a significant component to the system for dealing with the amount ofwater in the Eagle Mine. That is, it was long known that there was a significant in-flow of clean water(not polluted with dissolved metals) into the Eagle Mine workings. This in-flow probably wasassociated with a solution channel that had been intercepted by a drift (exploratory mine tunnel) on the19th level of the mine and was estimated to flow as much as 200 gallons per minute (gpm).

Viacom has drilled a deep well, over 900 feet, and has been able to drill into this channel. Apump has been installed and over 100 gpm of this water is intercepted and pumped out before

6

it enters the mine workings. This pumping has significantly lowered the amount of water entering themine and becoming polluted with metals. The pumping has also allowed the mine water levels to befurther lowered, which, in turn, has resulted in a decrease in water that exits the mine through thefractured zone and into the Rock Creek drainage. EPA and the State have recognized the validity of theaddition of the deep well/pumping system by officially adding it to the agreed-upon cleanup plan. Thisaddition was described in a document titled “Explanation of Significant Differences,” which was issuedto the public in 1999. Electrical lines were completed to the pump site in the summer of 2000 which willprovide for reliable and continuing use of this system.

Although water quality trends in the Eagle River will be more fully discussed in a later section ofthis review, the addition of the seep collection/treatment plant has had a major positive impact onlowering the metals levels in the Eagle River. These actual values are discussed under the followingsection on Rock Creek and in the later section on overall metals levels in the Eagle River.

Under the current Three-party Consent Decree, the plant will be operated for ten years, or until2006. Viacom may be able to develop a new approach to dealing with the polluted water currentlybeing treated. However, a new consensual agreement, or unilateral order, may have to be developed tokeep the treatment and collection system on-line. The integrity of the bulkheads are checked on aregular basis and will continue to be checked as long as they are in place. The water treatment plant willbe required to meet its discharge permit as long as it is used. Regular operation and maintenanceactivities are performed as part of the Consent Decree to protect the integrity of the seep collection anddelivery system and will be followed as long as they are used.

The Original Consent Decree limited seepage from the mine to a rate no greater than 0.05cubic feet per second (cfs) from any one location. This provision remains in effect until a new agreementis developed.

When the water treatment plant first became operational it produced approximately 150 cu/ydsper day of wet sludge. This sludge was placed in the CTP. In 1994 Viacom added a sludge dewateringsystem to the treatment process. With this system, the sludge volume has been cut to approximately 5cu/yds per day. This dried sludge (it is dewatered to an average density of 44.8 percent solids) is astable sludge which is not considered a hazardous waste under Resource Conservation and RecoveryAct (RCRA) criteria for hazardous waste. The sludge is placed in a lined cell on the CTP. The cell hasanother approximated 5 years capacity. Once this cell is filled to capacity, and the treatment plant is stilloperational, another cell would have to be constructed. In 1998, the treatment plant generated 2,491cubic yards of sludge.

Rock Creek

As described in the preceding section, activities in the Rock Creek drainage are a majorcomponent of the pollution control activities directed at the Eagle Mine. This small perennial

7

creek flows from above the Townsite of Gilman, cuts down a very steep canyon before it meets theEagle river, and establishes the northern boundary of the mine workings area. Rock Creek, because ofthe mine seeps, the presence of waste rock from the mine intermingled with the colluvial material in thecreek bed, and run-off from several large waste rock piles in the lower drainage, has been a source ofmetals loading to the Eagle River. Most of the Eagle Mine seepage surfaces along the southern bank ofRock Creek.

The first major cleanup activity that took place in Rock Creek was, as previously stated, theinstallation of a mine seep collection system. The mine seepage collection system transports thecontaminated water to the treatment plant via a plastic pipeline installed inside the old tailings slurry line.This system, although not capable of collecting 100% of the seepage, has markedly reduced mineseepage flow into Rock Creek. Rock falling from the canyon walls requires frequent maintenance of thecollection structures. As stated in the previous section the lowering of the mine pool has reduced and, insome cases, nearly eliminated flow from some of these seeps.

As part of the Three-party Consent Decree, Viacom was required to collect ground water inthe lower Rock Creek drainage. This ground water flow, like the visible seeps, also contained asignificant load of dissolved metals. Viacom was given the option of meeting either of two performancestandards in designing and operating this system. These options were: (1) extracting and treating 90percent of the subsurface flow occurring prior to the start of mine draw down or collecting andeliminating all surface flow, or, (2) reducing metals transport so that water quality in the Eagle River atStation E-11 meets ARARS (i.e., standards). Viacom has demonstrated compliance with the first ofthese two options. The system installed was a gravity/siphon type. In 1998, this collection systemcollected between 1.5 and 5.5 gpm of ground water.

Also, as part of the requirements of the Three-party Consent Decree, most of the flow of RockCreek is now diverted into a piping system at a point above where the first mine seeps are located. Thewater is diverted around the seep area and into the Eagle River. This system helps reduce the volume ofwater collected by the siphon system and sent to the treatment plant. This is clean water that has notcome in contact with any mine related waste piles.

Though still a source of metals loading to the river, Rock Creek is now less of a source metalsloading. This downward trend in Rock Creek’s metals contribution is illustrated in the following graph:

* Note: Scale on this graph is 100 mg/l Dissolved Zinc.

8

Before the mine seeps were better controlled, the dissolved metals levels in Rock Creekgenerally ran at their highest during low flow in the December-March time period. In December, 1993,and January, 1994, for instance, these values were 20.4 mg/l zinc and 27 mg/l zinc, respectively. InMarch, and April, 1994, the dissolved zinc ran at 19.2 mg/l and 19 mg/l. When the peak snowmeltoccurred from the higher part of the watershed in May and June, the zinc levels dropped to 1.2 mg/land 3.41 mg/l, respectively. These later numbers reflect the dilution effect of high flows.

In 1999, however, in the low flow time of year (January), the dissolved zinc level in RockCreek was only 7.030 mg/l at a 35 gpm flow rate. This was actually a lower flow rate than thatassociated with the zinc values given in the preceding paragraph for January. Thus, there was less of adilution effect. The zinc values then increase to 10.7 mg/l in March and 24 mg/l in April. Although theflow rates differ between these different years, it is clear that the drying up of some seeps by loweringthe mine pool, improvements in the collection system, the rerouting of up-stream clean water around thesite, and the collection of ground water have had a cumulative impact on lowering the Rock Creekarea’s metals contribution to the Eagle River. The dissolved metals values do continue to increase inMarch and April because of the early snowmelt and runoff in this lower part of the canyon.

In the 1991 “Report On Loading To The Eagle River,” Rock Creek was shown to becontributing 25 to 55 lbs/day zinc for low flow times of the year and increasing to 200 lbs/day duringhigh flows. Data from the 1999 “Eagle River Water Quality Report” reveals that Segment 3 (RockCreek) added an average of 13 lbs/day of zinc to the Eagle River. The highest load measured came onApril 15,th at 51.7 lbs/day. Roughly 50 percent of the load increase was attributable to Rock Creeksurface water and 50 percent was from unaccounted sources. Overall, Rock Creek cleanup effortshave resulted in a significant decrease in this source of metals loading to the Eagle River.

9

Polychlorinated Biphenols (PCBs)

When the Eagle Mine was first abandoned by its owner, at that time Mr. Glen Miller, EPAconducted an emergency action to remove electrical equipment from the flooding mine. Much of thisequipment contained PCB’s (polychlorinated biphenols). Most of the equipment in the mine wasremoved and the PCB’s were taken to a licenced facility for disposal.

Because of extremely hazardous conditions, including a partially collapsed tunnel and anon-going mine fire, three transformers were not removed. Although the transformers were not removed,the PCB’s from these transformers were drained and recovered. Though drained, it is estimated that asmall amount of PCBs remain in the electrical equipment. In 1992, EPA completed an evaluation of therisk to public health from these remaining PCB’s (“Risk Assessment Of PCB’s In Eagle Mine At theEagle Mine Site, Minturn, Colorado”). Taking a conservative approach, that is, calculating that all of thePCBs left the mine and entered the Eagle River at once, EPA determined there would be very little riskto human health. The risk assessment was issued to the public in January 1992, and is available onrequest. The mine pool was sampled for PCBs on a quarterly basis for 8 years. Because no PCB’shave been detected in the mine pool sampling has been discontinued.

Waste Rock/Belden Area

One aspect of the Eagle Mine cleanup that has been difficult to fully address has been the largequantities of waste rock located in the mine area. During the course of the development of the EagleMine, large quantities of waste rock were dumped on the mine site. Thus waste rock has come out ofthe several mine portals and lies in various locations, mostly on the steep canyon slopes immediatelybelow the abandoned Town of Gilman. Some waste rock piles are located down the canyon side andvery near the river. A total of 16 waste rock piles have been delineated but other scattered waste rockalso exists. A rough estimate is that there are 1,500,000 cu/yds of this material. Although not generallyof “ore” quality, some of these waste rocks contain elevated levels of metals. The State and EPA havelong had a concern that snow-melt and rainstorm events send water through these piles and that thiswater picked up metals which then became a source of loading to the Eagle River.

Another complication of this issue is the railroad bed that runs along the east side of the river forover a mile in the Belden area. Belden is the location of mine facilities in the Eagle River canyon and iswhere the main mine portals, the drying house, and ore loading facilities are located. The railroad bed isprobably composed of at least some waste rock from the mine. Runoff from the canyon walls,snowmelt, and direct contact of the river with this waste rock, especially in large runoff years, likely addmetals to the river.

Zinc loads from this area in 1991, as found in the “1991 Report On Loading To The EagleRiver,” were estimated at 21 lbs/day to 71 lbs/day, with a high of 282 lbs/day in high flow. Again,because of the differences in flow rates between the years, it is difficult to make direct comparisons butdata from the annual “Eagle River water Quality Report -1999”

10

illustrate that the Belden area remains the largest single source of zinc loading to the river. Thisdocument states that “most of the dissolved zinc load in Segment 1 of the Eagle River (the Belden area(segment) was from unaccounted sources.” The zinc load averaged 30 lbs/day. In the fall of 1999, itwas reported that the measured contribution was from 22 to 40 lbs/day. It should be noted that themetals load in this segment also included the contribution from the Roaster Drainage on the western sideof the river. This averaged about 5 percent of the load addition, or less than 2 lbs/day. In the 1991report, the Roaster Drainage contributed 6-9 lbs/day of zinc during low flow to this segment.

Examining results from water quality data collected from the monitoring station above thissection of the Site, and comparing it with data from below, also illustrates the metals contribution of thisarea. The Belden area is bracketed by monitoring stations E-3 and E-5, and is known as Segment 1.E-3 is above the mine and represents the river as it enters the impacted area. E-5 is below the minearea, but above Rock Creek. Values will be shown for dissolved zinc only. The zinc data shown belowis for March (low flow time - concentrations are at their highest) and for September (river is at more ofa “base flow” state). Values are shown in milligrams per liter (mg/l). The measured stream volume isalso reported in cubic feet per second (cfs):

September 26, 1999 March 25, 1999

E-3 (70.2 CFS) - .005 mg/l U* E-3 (52.6 CFS) - .082 mg/l

E-5 (71.5 CFS) - .064 mg/l E-5 (69.7 CFS) - .178 mg/l

* U = below detection limits

Because of the small size of the above data set, it should not be over-interpreted. It is,however, offered to illustrate that the Eagle River enters the project area with a low zinc load (there areprobable small sources above the mine area) that increases, especially during low-flow periods, as itflows through Belden.

Although the Original Consent Decree made some improvements by requiring the diversion ofstorm- event/snow-melt water away from some of the piles, the piles remained a concern. Efforts wereundertaken under the Three-party Consent Decree to better understand the metals loading role of thewaste rock. Under this decree, Viacom agreed to more accurately delineate the waste rock piles, toanalyze the leaching potential of these piles, and to monitor snowmelt and rainfall events from thedrainages in this area. The study was conducted in 1995-97.

The study concluded that out of the 16 identified waste rock piles, 4 had the most potential toleach metals (acid generation potential), 8 had minimum or no potential to generate acid, and 2 had noidentifiable pathway to the Eagle River. Actual snowmelt/rainfall monitoring results, however, did notreveal large quantities of metals coming into the Eagle River from the piles. The final report on thisproject, “Data Evaluation Report - Belden Area,” states that “the

11

combined zinc load from the Site during rainfall-runoff periods constitutes less than two percent of theannual dissolved zinc load measured at Station ER-11.” The report also concludes that “duringsnowmelt periods, Belden reach tributary areas contributed an average of 9 percent of the dissolvedzinc load measured at Station ER-5.” Thus, while the data suggested that the Eagle River receivedsome zinc load from the various tributary channels associated with the waste rock, the discharge isrelatively small and the zinc load reaching the river was also relatively small.

The data did reveal that there was a noticeable increase in the zinc load in Rock Creek duringsnowmelt and rainfall events and that this could be most attributable to runoff from Waste Pile 8 locatedin that drainage. It was also known that during spring runoff and during the warmer times of the year,water seeped from the toe of this pile. Grab samples taken from these seeps showed elevated levels ofmetals. In 1999, Viacom began to address this problem by constructing a seep collection system todivert this Waste Pile 8 seep water into the Eagle Mine workings. Though no monitoring results are yetavailable, it is expected that this will lower the zinc load in Rock Creek.

Because Rock Creek enters the Eagle River below monitoring station E-5, this expected zincload reduction should not be linked with the numerical values discussed above, which are related to theBelden segment. If this reduction does occur, however, the load change will be picked up bymonitoring at Station ER-11 and should be linked with the discussion of the loading associated with theRock Creek segment of the river.

Another probable source of metals loading in the Belden area was related to a significantquantity of “product” that was left in the drying house and had been spilled outside during prior loadingand handling activity when the mine was operational. This product was milled and dried ore that wasready for shipment to a smelter. It contained a high percentage of zinc. Although it was difficult toquantify, the State and EPA believed that rainfall and snowmelt was probably picking up zinc from thisproduct and adding this zinc load to the Eagle River. The agencies also believed this situation wouldprobably worsen as the drying building continued to deteriorate through time.

In 1997 Viacom cleaned up most of this spilled product. In that year they contracted with awaste disposal firm to clean the drying house of all remaining product and to scrape up approximately100 meters along the top surface material along the front of the drying house and the loading facility.This work has been completed and the material placed in the CTP.

As stated previously, the whole Belden area, including the associated waste rock, remains asone of the most difficult set of problems on the site. While the various efforts to address these problemshave no-doubt lessened the zinc load reaching the Eagle River, this area remains as the single largestcontributor of zinc. EPA and the State have not proposed any further work in this area at this time butwill review the situation following the finalization of biological-based in-stream standards for the river.Any further effort to deal with these large quantities of waste rock be subject to a completecost-benefit, engineering, and environmental

12

analysis as required by the National Contingency Plan. However, ground water in the Belden area is aprobable source of metals loading and, as such, is still being investigated.

Roaster Piles

In the early days of the mine’s history the miners used an ore smelting process called “roasting”which heated the ore to remove the metals. The residue from this process, roaster material, wasdumped on-site. When the Superfund cleanup began, there were 5 distinct roaster piles on-site, onelarge pile (Pile 3) on a steep slope on the western bank of the river; two more large ones (Piles 1 and2) behind the first in a side drainage (Roaster Drainage) which is across from Belden, and; two smallerones (Piles 4 and 5) on the east side of the river. The tail of Roaster Pile 3 actually was undercut by theEagle River. The volume of all 5 piles was 120,000 cu/yds. These piles contained material that wasvery high in metals content and were a source of metals loading to the Eagle River, especially duringsnowmelt and rainfall events.

As part of the Original Consent Decree, Viacom agreed to remove the 5 roaster piles andrevegetate these areas. This activity was completed in 1989 and the material placed in the CTP.Additional materials were removed in 1990 and 1992. A small quantity of roaster material remains onthe east-side canyon wall, in an area very difficult to access. Some amount of roaster material remainsas part of the railroad bed in the Belden area. A non-quantified amount of contaminated soils in theRoaster Drainage also remains which was not feasible to remove.

The main roaster pile area on the west bank, Roaster Piles 1, 2, and 3, now contribute onlyminor amounts of zinc to the Eagle River. This small drainage is monitored and the cleanup of this areahas been very successful in reducing metals loading. In terms of zinc loading, prior to remediation, theRoaster Drainage contributed 20 to 30 lbs/day during low flow. High flow contributions (snowmelt) ranas high as 270 lbs/day. Monitoring results in 1999 show that, on the average, the Roaster Drainagecontributed less than 2 lbs/day of zinc. The two former roaster pile areas on the east bank, RoasterPiles 4 and 5, do not contribute quantifiable amounts of zinc to the river.

The following graph depicts the dissolved zinc values for the month of March from the earlypart of the cleanup (1991) through 1998, as measured at the mouth of the Roaster drainage:

* Note: Scale on this graph is 100 mg/l Dissolved Zinc.

13

According to the 1998 “Eagle Mine Annual Site Monitoring And Activity Report” the impactedpart of the Roaster Drainage had a vegetation cover of 51.4 percent with 7 identified plant speciespresent. The revegetation performance standard is defined in the Three-party Consent Decree’sStatement of Work, as a reclaimed area comprising a minimum of 50 percent of the appropriatereference area cover, with no one species comprising more than 80 percent of the cover. Compliancewith the longer term revegetation standard, required by the Original Consent Decree, has not beendetermined.

Rex Flats/Old Tailings Pile

A froth flotation mill was added to the Eagle Mine operation in 1929. The mill is located in themine workings and the tailings from the milling were slurried down the canyon for approximately 1.5miles for disposal at the first large open area. From this time, until 1946, this disposal took place on anarea on the west bank of the river and the pile itself became known as the Old Tailings Pile (OTP). TheOTP was abandoned in 1946 and the slurry line extended about another mile downstream. The tailingswere then deposited at another site, also on the west side of the river. This pile became known as theNew Tailings Pile. The OTP covered about 40 acres and was a significant source of metals loading tothe Eagle River through surface runoff and ground water migration. Approximately 1 million tons oftailings were deposited at the OTP.

The Rex Flats area is about a 20 acre site directly across the river from the OTP. The slurryline that was extended to the New Tailings Pile was constructed across Rex Flats. During the time thisslurry line was in operation, a quantity of tailings were deposited on Rex Flats. Some of this tailingsrelease was done to suppress vegetation growth under the wooden trestle and slurry line. This wasdone to lessen fire threat to these wooden structures. There was also probable spillage of some tailingsfrom the slurry line.

14

Under the terms of the Original Consent Decree, Viacom agreed to remove the tailingsfrom both areas, place them in the New Tailings Pile (then became known as the ConsolidatedTailings Pile or CTP), and revegetate both areas. This work was completed in 1991. Over 40,000yards of clean fill was been placed on the OTP to maintain drainage and provide a suitable seedbed. The area has been revegetated. The standard found in the Three-party Consent Decree of areclaimed area comprising a minimum of 50 percent of the reference area, with no speciescomprising more than 80 percent of the cover, was met for most of these two areas in 1997.Additional remediation was necessary for parts of the two areas in June and July 1998.Monitoring in August, 1998, indicated that these areas had come into compliance. A previouslyunknown buried deposit of tailings in Rex Flats was discovered and was removed in 1996.Revegetation standards found in the Original Consent Decree’s Remedial Action Plan (RAP),however, have not been attained.

Before the tailings were removed from these two areas, and they were revegetated,dissolved zinc levels measured below this section of the Eagle River ran from 0.9 to as high as 2.1mg/l (Nov. to Feb., 1991). Zinc loading ranged from 95 lbs/day to 245 lbs/day with highs of 675lbs/day during Spring runoff. Data from the 1999 annual Water Quality Report, by contrast, showdissolved zinc at .206 mg/l in October and at .309 mg/l during the low flow time of year in March.According to this same report, for 1999, this segment of the Eagle River now contributes anaverage of about 5 lbs/day of zinc to the river, a significant improvement related to cleanupefforts.

Rex Flats/Old Tailings Pile Ground Water

Ground water beneath both Rex Flats and the OTP contain elevated levels of metals.Though the metal levels have shown improvement, more so in the OTP than at Rex Flats, thisground water would have to be carefully tested before it could be used for unrestricted humanconsumption. Both arsenic and cadmium levels have been found above drinking water standardsin some of the monitoring wells in these areas as late as 1998. Location of monitoring wells in theOTP and Rex Flats areas are shown in Appendix A of this report.

The following graphs depict dissolved zinc levels from 1990 to 1999 from three OTPmonitoring wells and from two Rex Flats wells (“D” signifies a deep well - “S” signifies a shallowwell):

Note: The scales on the OTP and REX FLATS graphs are 3,500 mg/lDissolved Zinc.

15

16

17

18

In 1990, Viacom was required, by RAP Amendment No. 1, to construct 3 extraction wellsin the OTP to pump ground water which was to be sent to the treatment plant. Because of thenature of the geology involved, i.e., very tight clays, these wells would produce only very smallvolumes of water and the wells were abandoned. No extraction wells were proposed for the RexFlats area. The ground water from both areas will continue to contribute small amounts of metalsto the river for an unknown amount of time until natural attenuation and flushing clean thesealluvial aquifers. Both these areas need to be carefully regulated to prevent exposure of underlyingmaterial that might contain elevated levels of metals. The vegetation should not be disturbed.Diversion ditches that partially circle the OTP and keep upgradient water from running across thereclaimed area must remain functional and not be disturbed. These ditches will also requireperiodic cleaning and maintenance. As previously stated, the ground water from beneath bothareas should not be used for human consumption.

19

Consolidated Tailings Pile

By the early 1940’s, the Old Tailings Pile was no longer useable so the Eagle Mineoperators found another site for tailings disposal approximately one mile downstream on the westside of the river in the area known as Maloit Park. The resulting tailings pile, started in 1946,became known as the New Tailings Pile and was used for tailings deposit until the mine closed.Approximately 9 million tons of materials were deposited at the site covering some 69 acres.

As part of the Original Consent Decree, it was decided that all surface wastes (mostlytailings and roaster material) would be consolidated at this site. The pile was to be covered with amulti-level cap and revegetated. Because of this consolidation of wastes, now complete, the NewTailings Pile has been renamed the Consolidated Tailings Pile (CTP). The cap construction isfinished and the project has received final approval by the State.

The revegetation performance standard for the CTP is included in the Original ConsentDecree’s Remedial Action Plan. This document contains specific revegetation criteria to beapplied to the CTP. Revegetation of the CTP was completed in 1998 and compliance with theperformance standard is targeted for 2002.

At the beginning of the Superfund cleanup, the CTP was composed of approximately ninemillion tons of tailings material. The pile was uncovered, open to the elements, with steep erosiveside-slopes. Some of this material had eroded into the adjacent wetland. A pond of acidic watercovering approximately 6 acres was on top of the pile.

The pile was also the source of major metals loading to the Eagle River. Snowmelt,rainfall, and the historic pond were all sources of water that would infiltrate through the pile,dissolve metals in the tailings, and then pollute the ground water under the pile. This groundwater would then enter the Eagle River running along the east side of the pile and the lower partof Cross Creek running to the north of the pile. Though later proven not to be the case, there wasalso concern the uncovered pile had been a possible source of particulate matter, containingmetals, that could have blown off the pile and onto the surface soils at the nearby Minturn MiddleSchool and nearby residences. In addition, the ground water under the pile posed a possible threatto two drinking water wells, located on the north side of Cross Creek across from the wetlands,which were used by the Town of Minturn. Last, past migration of tailings off the pile hadimpacted the adjacent Maloit Park wetlands.

Under the Original Consent Decree, the pile has been reshaped with the side slopes gradedto stable configuration of 5/1. The whole pile has been capped with a multi-layered cap designedto inhibit moisture from infiltrating through the pile and dissolving metals. The final layer iscomposed of clean soil which has been seeded with various species of grass. The vegetation notonly holds the top level of soil in-place but also transpires a significant amount of moisture backinto the atmosphere. The capping has also eliminated any potential for particulate matter to beblown onto adjacent areas. Run-on control ditches were built along the

20

up-gradient side of the pile to capture surface runoff from adjacent areas and prevent the waterfrom flowing across the pile. Also, other waste material removed from other areas during thecleanup have been deposited at the CTP. These wastes include the tailings from the OTP and RexFlats, the roaster pile material, mill product that was removed from the Belden area, treatmentplant sludge, and a large quantity of wetland soils with elevated metals content that was removedfrom the Maloit Park wetlands. The addition of this other material has made a total CTPrepository of over 9 million tons. The cap was completed on the pile in 1997.

As stated, the CTP has been a major source of metals loading to the Eagle River, mainlyfrom ground water flow discharging into the river and into Cross Creek. Cross Creek runs alongthe north of the Maloit Park wetlands area and joins the Eagle River directly below the pile.Rainfall, snowmelt, and the presence of the historic pond on top of the CTP all were sources ofthe water driving through the pile and dissolving metals. The following sets of data illustrate andcompare the metals loading role of the CTP prior to remediation versus the piles contributionusing the most recent data ( i.e., 1999). Values shown are for monitoring Station 13B, which is onthe Eagle River above the confluence with Cross Creek, and for Station T-18, which is the lowerCross Creek station. Data from both stations are given because, as stated, ground water from theCTP flows into both the Eagle River and into Cross Creek. Monitoring results shown are for theMarch low-flow time of year. Though this is a small data set, it is illustrative of the progress thathas been made in controlling the metals loading from the CTP since the cleanup began:

Early Part of Remediation (1991) Current Situation (1999)

E-13B (3/26/91 @ 27.6 CFS) = 3.65 mg/l E-13B (3/26/99 @ 73.1 CFS) = .469mg/l

T-18 (3/26/91 @ 5-10 CFS est.) = 99.6 mg/l T-18 (3/26/99 @ 16.1 CFS est.) = .044 mg/l

In the 1991 “Report On Loading To The Eagle River,” it is reported that the CTP areaadded from 155 to 395 lbs/day of dissolved zinc to the river. This loading value went up to asmuch as 640 lbs/day during runoff. The 1999 report shows the zinc load from the CTP asaveraging about 12 lbs/day. The report also notes that about 5 lbs/day comes from the treatmentplant discharge. Cross Creek is reported to carry less than 4 lbs/day dissolved zinc. The followinggraph illustrates the progress that has been made:

* NOTE: The scale on this graph is 100 mg/l Dissolved Zinc

21

CTP Ground Water

CTP ground water has been monitored since the beginning of the cleanup in 1988 throughthe installation of a number of monitoring wells. Though a number of these wells are no longerbeing sampled, the map in Appendix A depicts the location of the extensive monitoring wellsystem that has been used for this part of the site. The wells currently being sampled includeNTP-MW 1, 3, 4, and 5. This map also depicts the two extraction trenches that collect groundwater along the east side and the north side of the pile, respectively. The water collected fromthese trenches is tested for dissolved metals concentrations. Last, the map depicts a sump on thenorthern side of the pile that was installed to intercept and collect ground water associated withan old decant pipe located in the pile. The water collected by this sump goes to the treatmentplant and is also sampled.

The following data sets are presented to illustrate zinc values that were found in 1998 inthe wells currently being monitored for CTP ground water:

NTP-MW 1 - Northwest - (on 4/7/98) = 34.600 mg/l; (on 9/22/98) = 44.100 mg/l

NTP- MW 3 -East - (on 4/6/98) = .005 U mg/l; (on 9/22/98) = .005 U mg/l

NTP- MW 4 -Maloit North - (on 4/7/98) = 62.400 mg/l; (on 9/22/98) = 48.500 mg/l

NTP- MW 5 -North - ( on 4/7/98) = 1110.000 mg/l; (on 9/22/98) = 846.000 mg/l

22

The following graphs are for the same set of wells but cover the time period from thebeginning of the cleanup in 1990 to 1998. NTP-MW-3 is not graphed because it is an upgradientwell. No elevated zinc levels have ever been found in this well. The months of March andSeptember are shown on the graphs. March generally has the highest zinc concentrations becausethere is less ground water at that time for dilution. The ground water elevations are generally afoot or more higher in September than in March for most of these wells. Several other CTP wellshave been monitored for a number of years, though regular monitoring of these wells was stoppedin 1997. These wells include NTP-MW-2 (Southeast), NTP-MW-6 (East), NTP-MW-7D (MaloitPark-Deep), and NTP-MW-7S (Maloit Park-Shallow). The two No. 7 wells have shown onlysmall amounts of dissolved zinc and will not be graphed.

* Note: The scale on the NTP wells is 3,500 mg/l Dissolved Zinc.

23

24

As can be seen, there is a downward trend in zinc concentrations for most of these wells, exceptfor MW-5. Monitoring, and past modeling efforts have indicated that the worse part (highestconcentrations) of the ground water plume is under the northeast part of the CTP. The graphedresults for NTP-MW-5, which monitors ground water in this area, bears this out. An analysispresented in the 1998 Annual Report indicates that there has been no release of dissolved metalsto the deeper aquifer underlying the CTP.

Extraction Trenches

Under the Original Consent Decree two ground water extraction trenches wereconstructed along the CTP. One was on the north, between the CTP and the Maloit Parkwetlands, and the other along the east, between the CTP and the Eagle River. Originallyconstructed to collect ground water and deliver it to the mine pool, this scheme was soonabandoned and the water has since been delivered to the water treatment plant for treatment. Bothtrenches have been extensively modified, with improvements added, since they went intooperation. Water level information, as related to the functioning of the trenches, is gathered by asystem of related wells. Flow rates (non-spring) run about 35 gpm for the north trench and about8 gpm for the east trench.

Water samples have been taken from the trenches since 1995. Results from the east trenchtaken from 1995 to 1998 indicate that the collected ground water contains dissolved zinc atconcentrations ranging from approximately 107 mg/l to 665 mg/l. Dilution from spring snowmeltcauses concentrations to drop seasonally. Dissolved zinc in 1998 was the lowest since 1995,ranging from 107 mg/l to 180 mg/l. The “Annual Site Monitoring and Activities Report - 1998”states: “...the trend toward lower dissolved zinc concentrations may be attributable to animprovement in ground water quality from the CTP.” It is also noted that Eagle River water mayinfluence these values. Sample results from the north trench (collected from the north-sump)indicate that the collected ground water contains dissolved zinc ranging from approximately 50mg/l to 310 mg/l. There does not appear to be seasonal fluctuations in the north trench. Collectionand treatment of this ground water, along with the other remedial activities at the CTP, has helpedlower this area’s contribution of metals to the Eagle River.

Upgradient Ground Water Diversion Trench

The CTP well location map in Appendix A also depicts the location of an upgradientground water diversion trench (UGT) located along the western edge of the CTP. This buriedtrench/pipe system diverts upgradient clean ground water that is entering the area from the westaway from the pile. This water is diverted into the Maloit Park wetlands and is an importantsource of recharge for the wetlands area. The wells labeled as “DT” wells shown on the same mapand are used to monitor the trench. These wells are sampled on a regular basis for dissolvedmetals concentrations.

When this system was first put into operation, it was discovered that it was dischargingwater high in dissolved metals. The high metals levels was probably related to the presence, at

25

that time, of the historic pond on top of the pile. A hydraulic head was created with the pondwater, containing high levels of metals, moving to the trench. The trench was then closed (1990).After the historic pond was eliminated and the pile capped, an evaluation was conducted on thefeasibility of reopening the UGT. During the feasibility test, conducted in the Summer of 1998,the trench discharge was sampled on a regular basis and the dissolved metals levels, plus othermonitored constituents, were within agreed upon limits.

The UGT discharge is governed under Superfund and must meet State substantivepermitting requirements. These requirements set discharge limits for various constituents,including dissolved metals. Until recently, the trench discharge was within the permit limits.However, recent sampling in Spring, 2000, revealed that cadmium and zinc values were above thepermit limits for two sampling episodes, and magnesium was above the limit for one sampling.The cadmium limit is 0.0004 mg/l and the values ran 0.0037 mg/l on April 8, 2000, and ran0.0018 mg/l on April 22, 2000. The dissolved zinc limit is 0.23 mg/l and ran 0.643 mg/l on April8, 2000, and 0.433 mg/l on April 22, 2000. The magnesium limit is set at 62.2 mg/l and ran 63.7mg/l on March 25, 2000. The diversion system was shut down and has since been retested. Thevalues for the latest testing were below standards and the trench has been reopened.

The most recent results for the wells used to monitor the UGDT show dissolved zinclevels all less than 1 mg/l. The trend of metals concentrations in these wells has been downward.It is estimated that before the most recent closure of the UGDT, approximately 3.8 million gallonsper year of clean water was diverted to the wetlands area (based on 1998 flow rates andextrapolated to a March through October operating period). This volume of water has, thereby,not become contaminated and, at the same time, helps recharge the wetlands.

As previously stated, the cleanup efforts at the CTP have made a measureable difference inlessening the load of metals reaching the Eagle River. Daily zinc loads have fallen from 155 to 395lbs/day in 1991 to approximately 12 lbs/day in 1999. This drop in zinc load can be attributed to acombination of the pile’s capping and collection and treatment of ground water. This positivetrend is dependent on protection of the cap and the continuing treatment of ground watercontaining elevated levels of dissolved metals.

CTP Public Health Issues

As previously discussed, when the Superfund cleanup began in 1988, the CTP was notcovered and was subject to wind erosion and some material had eroded, particularly off thenorthern side of the pile. There was concern that tailings particles, containing metals, had blownonto the nearby surface soils in the Minturn Middle School, and nearby housing areas, during the30 + years the pile had been in existence. There was also concern that dust would be createdduring the period the pile was being reworked, as OTP and roaster material were beingconsolidated in this same pile, and the consolidated pile was being capped. There was also someconcern that the tailings material that had been eroded into the wetlands area to the northcontained probable elevated levels of metals. These potential problems were addressed in threeways.

26

First, the Original Consent Decree required air quality monitoring and contingencyplanning for all construction work at the CTP. Extensive dust control measures were requiredduring all construction activities. High volume air samplers were placed between the pile and theschool, between the pile and the south end of Minturn, and, for a time, on top of the school. Anair quality permit, issued by the Colorado Department of Public Health and Environment, wasrequired. Air quality samples were analyzed on a regular basis and no excess risk from airborneparticulates was ever found. With the completion of the CTP cap, this monitoring has beendiscontinued.

Second, extensive soil sampling was conducted in the school area, in adjacent employeehousing areas, and in the southern end of Minturn. No elevated levels of the metals of publichealth concern - arsenic, cadmium, and lead - were found. Results of the sampling indicated thesemetals were found at background levels, except for a small area north of Cross Creek. The areaacross Cross Creek is located on the ridge separating Minturn from Maloit Park and is on U.S.Forest Service property. Though there is no risk to the casual user from this area at this time, amore complete risk assessment would need to be completed if present uses were to change. Thecompletion of the CTP cap eliminates any future possibility of windblown particulate leaving thepile. This will be dependent, however, on the protection of the integrity of the cap. Soil sampleresults for lead and arsenic are found in Appendix B of this review.

Third, arsenic, cadmium, and lead were elevated in portions of the Maloit Park wetlandsabove levels considered too high for unlimited use, especially by children. Soils were sampled formetals along the school road that runs between the CTP and the wetlands area.

Though no observations had ever been made of children using the wetlands area orwalking along the road, at least during the time since the cleanup began, the material along theroad and wetlands soils with elevated metals levels were both removed. Both areas were coveredwith clean soils to a depth of at least one foot depth. The area immediately along the pavementwas covered with clean gravel. The contaminated material was placed in the CTP. Air quality wasstrictly monitored during all these operations and no violation of standards was ever observed.The upland area along the road was revegetated with dryland plant species and the wetland withwetland type plant species.

Another public health issue associated with the CTP was the possibility of dissolvedmetals impacting two Town of Minturn municipal drinking water wells. These wells were locatedon the north side of Cross Creek across from the Maloit Park wetlands area. Though the chancewas somewhat remote, there was the possibility that if these two wells were pumped at a long andexcessive rate, CTP ground water could be drawn under Cross Creek and into the wells. Viacomprovided Minturn two new wells at a location well above any possible influence from the CTPground water. These new wells were completed in 1996. The existing two threatened wells were,in the meantime, sampled on a regular basis by the State. No excess metals (above drinking waterstandards) were detected.

27

Maloit Park Wetlands

The Three-party Consent Decree provide for the rehabilitation of the Maloit Parkwetlands area, which lies between the north edge of the CTP and Cross Creek. As discussedunder the previous section on public health issues, there was concern that excess levels of metalsin this area could have the potential to be harmful to public health, especially children. In addition,parts of the wetlands itself had been severely impacted (vegetation was severely stressed ornon-existent) by water and materials movement off the CTP. A complete evaluation was made ofmetals levels in the surface and sub-surface soils of the wetlands. Those areas containing levelsabove both human health, and vegetation stress, levels were removed and replaced by clean soil.These areas were then revegetated with native wetland plant species.

The 1998 Annual Report documents that the Maloit Park willow shrub and the sedge-rushreclamation are in compliance with the vegetation cover standard, but that neither area is incompliance with the similarity standard. The report also points out that the mix of plant species ischanging in some areas due to changes in the supply of water. One effect of intercepting groundwater flow moving through the wetlands area from the CTP area has been some change in theflow pattern and quantity of water supplying the wetland. Overall, a visual inspection of thewetlands indicates a successful cleanup of the area. The continuing status of the vegetation of thearea will, however, have to be monitored.

The Annual Report also notes that a noxious weed problem, mostly thistle, has developedin the reclaimed wetlands area. This is a common problem in reclamation projects and will bedealt with in the context of a control plan being developed. This plan will involve spraying ofapproved herbicides and will follow Eagle County spray regulations. This control effort isscheduled for the year 2000.

Eagle River Water Quality Standards

Attainment of in-stream water quality standards has been a major driving force behindcleanup efforts at the Eagle Mine. There are, however, currently three sets of in-stream waterquality standards related to the Segment 5 of the Eagle River. Segment 5 encompasses the Site.

First, the Colorado Water Quality Control Commission has set standards for Segment 5 ofthe Eagle River that reflect past degradation. The Commission, however, set these standards withthe understanding that cleanup efforts were underway at the site and with the expectation that thestandards would reflect water quality improvements from the cleanup. The Commission set thedissolved zinc value at .400 mg/l.

Second, the State and Viacom set another in-stream standard in their Original ConsentDecree. This standard, set on dissolved zinc, was .150 mg/l, to be met at a point below the mineworkings and Rock Creek (at Station E-11), and .250 mg/l zinc that was to be met at a point justabove the confluence with Cross Creek (at Station E-13B). These values were to be met in

28

September, based on an average flow year. As reported in the “1999 Annual Water QualityReport,” these two values were met, or were lower, for both sample points, for 1998 and 1999.

The third set of Eagle River in-stream water quality standards were developed by EPA andpublished in its 1993 Record of Decision. EPA set standards that would support a cold waterfishery. For dissolved zinc these were .106 mg/l.

EPA set the lower standard because it concluded the State/Viacom negotiated values of.150 and .250 mg/l dissolved zinc were not entirely protective. EPA reasoned that because theState/Viacom values had to only be met in September, zinc values would reach biologicallydamaging levels during low flow periods in Winter and early Spring when the concentrationswould go well beyond those two standards. The EPA standard of .106 mg/l dissolved zinc was tobe met year around, as measured at all sample points on segment 5 of the Eagle River. A map ofsample stations is found in Appendix A of this review.

The last, or fourth, in-stream standard is one currently being developed for Segment 5 ofthe Eagle River. This approach was proposed in EPA’s 1993 Record of Decision. This proposedstandards approach is “biological based.” Under this biological approach, EPA, the State, andViacom are attempting to develop an optimal range of the dissolved metals levels that wouldsupport a healthy and reproducing biological system in the Eagle River.

Under the biological based standards approach, metrics would be developed for both fishand aquatic insects. Metrics are measures of numbers of fish, and numbers and different taxa ofinsects (macro invertebrates). An index is also being developed which would quantify what thesemetrics (numbers of fish and insects, and numbers of insect taxa) should be in a “healthy” EagleRiver. This methodology uses various statistical and observational techniques. Actual fish andinsect sampling would then occur at regular intervals at 5 stations on Segment 5 of the EagleRiver. Results of the fish and insect sampling would then be compared with the index. Waterchemistry samples would be taken at the same time and linked with the actual measured biologicalvalues.

If the biological values (metrics) measured for three consecutive years were within theagreed upon index values, the water chemistry values, collected at the same time, would becomethe proposed chemical standards for the river. As an example, if the agreed upon fish and insectvalues for a healthy river were being met at a chemical value of .250 mg/l dissolved zinc, thisnumber would be proposed as the chemical standard for zinc on Segment 5. This approach hasbeen worked on for 5 years and is nearing completion in year 2000.

Eagle River Water Quality Trends

Cleanup activities have resulted in considerable progress toward restoring a healthy EagleRiver. This is true also in comparison with EPA’s more stringent standards. For the last twoyears, 1998 and 1999, in-stream sampling was conducted in January, March, April, August,September, and October. The following table gives dissolved zinc values for 5 of these months

29

for the last two years of record. All values are in mg/l for dissolved zinc. This chart is used to showexceedences of EPA’s current standard of .106 mg/l.

March April August September October

E-3 (up-stream) 1998 .164 .102 .006 .007 .0005

1999 - .082 .061 .006 .005 .0006

E-5 (above Fall Creek) 1998 - .318 .465 .082 .084 .068

1999 - .178 .276 .085 .064 .147

E-10 (above Rock Ck) 1998 - .348 .454 .076 .076 .060

1999 - .173 .266 .069 .060 .146

E-11 (abv Bishop Gulch) 1998 - .470 .652 .119 .121 .115

1999 - 263 .414 .097 .087 .195

E-12A (Below OTP) 1998- .895 .983 .137 .130 .137

1999 - .309 .383 .112 .103 .206

E-13 (abv Two Elk Ck) 1998 - .801 .675 .129 .114 .158

1999 - .446 .452 .130 .140 .208

E-13B (abv Cross Ck) 1998 - .756 .741 .138 .104 .180

1999 - .469 .420 .125 .143 .197

E-15 (below Cross Ck) 1998 - 1.000 .609 .107 .092 .145

1999 - .329 .371 .087 .096 .160

30

Though the above values do show continuing exceedence of EPA’s zinc standard, it should benoted they represent very significant reductions in zinc concentrations in the Eagle River since thecleanup began. In 1989, for instance, zinc values were over .400 mg/l in parts of the river. The abovefigures also reveal the seasonal variations in zinc levels that are related to volume of flow.

The following set of graphs of the main-stream sample station results illustrate dissolved metalstrends in the Eagle River for the last 10 years. Again, zinc, while the major pollutant in the river is alsoused as an indicator metal for the other metals, as well. All values shown in the graphs are in milligramsper liter (mg/l), for dissolved zinc, and for the March sampling episode. March is chosen because itrepresents generally the worse case, low-flow with little dilution effect, for the river. Most graphs coverthe time period from 1990 to 1999. A figure displaying the location of these individual sample points isfound in Appendix A. The sample points are described as follows:

1) Station E-3 is the site upstream of the mine area. This station depicts the river before the influence ofthe Eagle Mine. Small amounts of elevated dissolved zinc are sometimes detected at this site probablyindicating some upstream metals source.

2) Station E-5 is below the mine workings at Belden. The Roaster Drainage also comes into the riverabove this sample station.

3) Station E-11 is the station below where Rock Creek enters the Eagle River. Fall Creek, a majorsource of clean water, also comes in above this station.

4) Station E-12A is the station below the OTP and Rex Flats and picks up influence from both thesemetals sources.

5) Station 13B is the station immediately above the confluence of Cross Creek, another major tributary.This station picks up the influence of the CTP.

6) Station E-14 is the station below Cross Creek. The location of this station was moved severalhundred meters in 1998. The results from 1998 and 1999 are depicted on this graph along with thosefrom previous years at the previous location.

7) E-22 is located on the Eagle River immediately above it’s confluence with Gore Creek. This stationwas added as a regular sample point in 1998.

NOTE: The following set of mainstream Eagle River graphs use a 5 mg/l scale for the Y axis:

31

32

33

34

Eagle River Fishery

The Eagle River, originally a Colorado River cutthroat fishery, has been an importantrecreational resource for the State of Colorado. The river supports many thousands of hours ofrecreational fishing each year. At the time the Superfund cleanup began, however, this fishery resourcewas severely depressed from the reach beginning at the Eagle Mine and for a number of milesdownstream. Restoration of the fishery, along with the other organisms that support the fishery, hasbeen a major goal of the cleanup effort.

Though a number of factors, including volume of flow, sedimentation, other non-mine relatedimpacts, and disease, influence trout reproduction and survival, elevated levels of dissolved metalsrelated to mine activities have had a major impact. Along with charting the changes in dissolved metalvalues, the parties involved in the cleanup have closely followed the response of fish populations to thelowering metal levels in the mine impacted stretch of the river. Fish numbers (species and ageclassifications), along with macro invertebrates, are counted in early April of each year by the ColoradoDivision of Wildlife, with cooperation and assistance from other agencies, Viacom, private groups, localschool children, and interested citizens. The annual count has taken place every year since 1990. Theresults of this annual fish and insect count are published each year by the Division of Wildlife in adocument entitled “Annual Biological Assessment of the Eagle Mine Superfund Site.” Viacom alsocollects insect data and reports on the results.

Summary fish numbers from the annual reports are shown below. Note that not all stations weresampled in 1990, when the cleanup began, but that all stations were being sampled by 1994 (except forthe Bishop Gulch site). All stations were sampled in year 2000, and these results are compared withboth 1990, when 1990 results are available, and with 1994 at all stations, except for Bishop Gulch. Ascan be seen from the following chart, fish numbers have shown a substantial increase at all collectionsites impacted by the Eagle Mine activities:

35

Brown Trout Brook Trout Rainbow Trout Cutthroat Trout SculpinRedcliff (#1)

1990- 59 3 7 0 81994- 57 2 4 0 92000- 42 1 1 0 38

Above Belden (#1.9)1990- not sampled1994- 89 0 0 5 02000- 80 6 1 0 4

Belden (# 2)1990- 0 0 0 0 01994- 8 1 0 0 02000- 100 8 0 0 0

Bishop Gulch (#2.9)1990 - not sampled1994 - not sampled2000- 128 0 0 0

Above Two Elk (#3)1990- 1 0 0 0 01994 54 10 0 0 02000- 160 8 1 0 0

Forest Service (#4)1990- 1 2 0 0 01994- 38 8 0 0 02000- 217 10 0 0 0

Below Minturn (#5)1990- 8 2 0 0 01994- 83 12 1 0 02000- 224 13 0 0 0

Arrowhead (#6)1990- 35(high flows prohibited second pass - no other species on first)1994- 277 0 13 0 02000- 343 0 10 0 12

36

REVIEW OF OPERABLE UNIT-2

Background

Operable Unit-2 was created to evaluate the risk from several specific areas at the Site. Thepotential risks that were examined in OU-2 included those associated with soils in the Maloit Park area,surface soils and waste rock in the Gilman Townsite area, and private drinking water wells in theMinturn area. Note that there has been a certain amount of overlap between Operable Units 1 and 2.The restoration of the Maloit Park wetlands, for instance, was actually accomplished under an Orderrelated to EPA’s original 1993 Record Of Decision. Maloit Park soils, including the wetlands, and theTown of Minturn’s drinking water wells were also considered under the earlier OU-1 time-frame.These two areas were also discussed under the OU-1/CTP section of this review and will not bediscussed further here. The following discussion will focus on the Townsite of Gilman. A Record OfDecision (ROD) for OU 2 was made public in June, 1997.

Gilman Townsite

The Gilman Townsite sets on the bluff over the Eagle River Canyon and directly over the EagleMine workings themselves. The Town of Gilman, now abandoned, was a company town where asmany as 350 Eagle Mine employees and their families once lived. The town was founded in 1879 andabandoned in 1985. The site contains former homes, offices, mine-related shops and garages, a formerhospital, a laboratory, and buildings used for recreation activities and stores. Waste rock piles, theformer elevator access for workers into the mine, and at least one other mine opening are also locatedin Gilman. Although access to the site is restricted, at least to vehicles, there is a recurring trespassproblem with people walking into the site.

Prior Cleanup Activities At Gilman

Under the OU-2 ROD, EPA did not propose any cleanup activities at the Gilman Townsite.However, as the earlier OU-1 part of the cleanup was underway, and work under the Original ConsentDecree proceeded, EPA and the State became aware of a potential problem with hazardoussubstances remaining in the abandoned town area, as well as in Belden. A thorough investigationrevealed quantities of explosives, chemicals, and PCB’s contained in electrical transformers and otherelectrical equipment. These materials were accessible to trespassers and were a risk to human safety,especially a quantity of dynamite caps that were found in Gilman. Though no PCBs were found to havebeen spilled, and were contained in the various pieces of electrical equipment, there was the potentialthey could be released through weathering and vandalism.

Under the terms of an Administrative Order, Viacom agreed to clean up all these wastematerials. This cleanup was completed in September, 1992. The explosives were destroyed on-

37

site and all the chemicals that were found were collected and disposed of at a licensed facility, as werevarious pieces of PCB-containing electrical equipment. Even though Gilman contains other possiblyhazardous materials, such as asbestos fibers, these are not regulated under the Superfund statute andare not addressed here. The old buildings, some subsidence in certain areas, and several mine shafts allhave the potential to be a risk to public health and the trespasser. These risks also do not fall under theauthority of Superfund.

Soil Risk At The Gilman Townsite

EPA and the State were concerned about possible exposure to elevated levels of metals in thesoils material at the Gilman Townsite. Sampling of surface materials in 1993 revealed higher thanbackground levels of five metals - cadmium, chromium, manganese, lead, and arsenic. These elevatedmetals levels were found in parts of the site and were possibly above levels considered safe forprotection of public health. These soil sample results are shown in Appendix B of this review.

In 1997, EPA completed an assessment of risk to human health from these elevated levels ofmetals to the casual user of the Gilman area. The document describing the results of the risk assessmentwas entitled “Risk Assessment Summary for the Eagle Mine Site, Minturn, Colorado,” dated February11, 1997. The casual user only scenario was used because of the current land use and because the siteis closed to public access. Trespass was considered a casual use.

The overall conclusion of the risk analysis was that casual users of the site were not at risk fromthe arsenic, cadmium, chromium, or manganese found in the soil and waste rock. A slight risk tosensitive human populations (a pregnant woman) to exposure to lead, was found. However, this riskonly existed in the situation of an unlikely scenario of 90 days, or more, of exposure. An outline of thetype of complete human health risk assessment EPA would expect be conducted at the Gilman site ifexposures were more than casual (full time residential) was also provided in this document.

The selected remedy for the Gilman property under the OU-2 ROD was to require anypossible future redeveloper to complete a comprehensive risk assessment based on the land use andexposure scenario planned for the site. Any potential cleanup activities at the Gilman Townsite wouldthen be based and dependent on the results of this risk analysis. The burden of possible cleanup activitywould fall on the redeveloper.

Because of Eagle County’s role in local land use control, including potential limiting orrestricting future land uses at the Gilman site, EPA and the State have held discussions with EagleCounty on the possibility of their providing some type of special zoning for Gilman, as well as otherEagle Mine cleanup features. Eagle County’s continuing and local presence at the Site would offer thelong-term level of protection these features require. Also, any

38

redevelopment proposals for any part of the Site, including Gilman, would come first to the County forreview, and ultimate approval. No agreement between the County and EPA and the State has beendeveloped at the time of this review.

Conclusions for the Eagle Mine Site

As the data in this review shows, considerable progress has been made in lowering EagleMine-related dissolved metals values in the Eagle River, and tributaries. Though the dissolved zinclevels remain above EPA’s standard of .106 mg/l for the low flow months of the year, even this lowstandard is now being met during parts of the year. The State’s Original Consent Decree standards of.150 and .250 mg/l dissolved zinc have been met in recent years, as required, in September. Fishnumbers, especially for brown trout, have been increasing over the ten years of cleanup efforts. Inrecent years, these increases in fish have been substantial.

Public health issues once associated with the Eagle Mine wastes have either been eliminated orshown not to exist. Drinking water supplies for the Town of Minturn have been protected, soils withelevated levels of metals removed from the Maloit Park wetlands, the roaster material, and the tailingswastes at the OTP, Rex Flats, and CTP have all been contained under the CTP cap. Ground waterunderneath these three areas remains contaminated with metals above safe drinking water levels. Theyare showing some level of improvement in some areas. Ground water from the CTP area is collectedand treated. More than casual use of the Gilman Townsite area could potentially be a risk to publichealth unless mitigated. This determination would not be made until the land use changes and a full riskassessment is conducted.

EPA concludes that the remedies for OU-1 and for OU-2 are expected to be protective ofpublic health and the environment. As stated above, and in other parts of this review, the public isprotected from exposure to excess metal levels in the soil. Soils, tailings, and roaster materials withelevated levels are now in the capped CTP. Small areas of roaster material remain in the Belden areathat might be problematical, but public access is not allowed in this area and no long-term exposure tohumans is likely. Drinking water supplies are not threatened by excess metals in the area. Any possibleair pathway, with excess metals, to humans has been eliminated by the removal and placement ofmaterials in the CTP. Hazardous materials in the Gilman/Belden area have been removed.

The above conclusions are, however contingent on the protection of the CTP cap and theprotection of the integrity of the soils and vegetation on the OTP. They are also contingent upon thenon-use of ground water from under the OTP, Rex Flats, or the CTP. The question of whether theTownsite of Gilman can be considered for different land uses than present, will be dependent on furtherrisk analysis. Gilman, as is, is not a threat, at least from metals, to the casual user.

39

The environment is certainly much improved at all former waste pile areas and at the CTP. TheMaloit Park wetlands restoration appears to be very successful. It is anticipated that the setting of thefinal biological “goals” in the biological standards development process will assure the protectiveness ofthe fishery. Biological resources have shown dramatic improvement since the cleanup began.

Further cleanup initiatives at the Site are not planned for the near future. EPA and the Stateintend to finalize the biological-based in-stream cleanup standard for the Eagle River in the summer of2000. The agencies then intend to test these biological-based values for three years. If the selectedvalues are met, the agencies will proceed with deletion of the Site from the National Priorities List. If thevalues are not met, a second Five Year Review will be conducted (at the three year mark) to evaluatethe situation and ascertain whether further cleanup measures are warranted and feasible. Operation andmaintenance of project cleanup features will continue.

Recommendations and Requirements

1) Viacom should continue to pursue technologies that will lessen, and, if possible, eventually eliminatethe need for the continuing operation of the water treatment plant. This, of course, is dependent on theability to protect the Eagle River.

2) EPA and the State encourage Eagle County to take an active role in protecting site features frompossible future disturbance and to assist in assuring Gilman is redeveloped in a manner protective ofpublic health and the environment. Institutional controls at Gilman should be made enforceable by EagleCounty.

3) Viacom must continue water quality monitoring, operation and maintenance of the ground water andmine seep collection and treatment systems, surface and ground water diversion structures, and otherSite features as per the terms of the two Consent Decrees.

4) Revegetation requirements must be met per the two Consent Decrees.

5) The biological-based in-stream water quality standard should be set so that a standard of“protectiveness” can be measured at the next 5-year review.

Community Involvement

Eagle County citizens and local governments, especially the Town of Minturn and EagleCounty, have been involved in the cleanup of the Site since its beginning. EPA, the State, andrepresentatives of Viacom, have held numerous meetings, information sessions, and field trips for localcitizens and government representatives. Viacom published a regular newsletter, including versions inSpanish, on Site cleanup progress for a number of years. EPA awarded the Eagle River Environmentaland Business Alliance community involvement grants that allowed

40

this local representative group to hire its own independent technical consultants to review and commenton the various cleanup measures.

Five-year Review Procedures

This Five-year review was compiled and written by Mr. Gene Taylor, EPA’s Remedial ProjectManager for the Site. The graphs in this reports were prepared by Mr. Jack Whyte, SuperfundProgram Assistant. Mrs. Wendy Naugle, State Project Coordinator for the Site, and Mr. DickParachini, former State Site Coordinator, provided review and critique of the document. Viacom, andits technical consultants from Dames & Moore, provided technical comments on various aspects of thecleanup.

Several site inspections were conducted by EPA and the State during the summer of 2000. Aconstant State presence during the construction season was maintained at the Site until 1999. Abibliography of documents used in the preparation of this review is found in the Appendix.

Observations

EPA and the State strongly recommend that its efforts under Superfund be used in conjunctionwith local land use controls to help protect the long-term health of the Eagle River. Though mine relatedmetals have been the single most damaging pollutant to the river, and it’s biological resources,sedimentation from construction, pesticides, road oil, herbicides, sewage effluent, consumptive use ofthe water itself, and many other factors are all having an impact on the water quality of this river. Onlythrough the efforts of all groups and government entities will river quality be protected.

Last, EPA and the State would like to recognize the contribution of the Eagle RiverEnvironmental and Business Alliance (EREBA) to the progress that has been made in the Eagle MineSuperfund cleanup. The continued oversight and suggestions of this local group of dedicated citizenshas been instrumental in the level of success the effort has enjoyed. EREBA has been especially helpfulin helping the citizens of Eagle County understand the complex issues involved, including the varioushuman health risk assessments undertaken at the Site.

Appendix A - Maps

Appendix B – Soils/Metals Maps

Appendix C - Sources Used In Preparation of Report

“Annual Biological Assessment of the Eagle Mine Superfund Site - Eagle County,Colorado” - Prepared by Colorado Division of Wildlife, April, 1999

“Biological Monitoring Sampling and Analysis Plan for Eagle Mine Site SurfaceWater Biological Monitoring Program” - Prepared for Viacom by Dames &Moore, December, 1996

“Data Evaluation Report - Belden area - Eagle Mine Site - Minturn, Colorado” -Prepared for Viacom by Dames & Moore, December, 1997

“Eagle River Water Quality Report - Eagle Mine Site” - Prepared for Viacom byDames Moore, December, 1999

“Eagle Mine Site Quarterly Reports” - Prepared for Viacom by Dames & Moore

“Eagle Mine Annual Site Monitoring and Activity Report” - Prepared for Viacomby Dames & Moore, 1999

“Health Risk Assessment for Maloit Park Wetlands and Screening-LevelAssessment for Selected Areas - Eagle Mine Site, Minturn, Colorado”- Prepared for EPA by Morrison Knudsen Corporation, July, 1993

“Record of Decision - Eagle Mine Site - Operable Unit 1 - Eagle County,Colorado” - EPA, March, 1993

“Report On Loading To The Eagle River” - Prepared for ParamountCommunications, Inc., by Dames & Moore, December, 1991

“Revised Eagle Mine Sludge Disposal Plan” - Prepared for Viacom by EagleEngineering Services, Inc., April, 1998

“Record Of Decision - Operable Unit II - Eagle Mine Site - Eagle County,Colorado” - EPA, June, 1997

“Risk Assessment Deliverables” - Prepared for EPA by Morrison KnudsenCorporation, February, 1997

Suite 2500633 Seventeenth StreetDenver, Colorado 80202-3625(303) 294-9100 FAX (303) 299-7901

October 4, 1999

FIVE YEAR REVIEW REPORTEAGLE MINE SITE

MINTURN, COLORADO

Job Number: 29735-015-034

i

TABLE OF CONTENTS

Page

1.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2.0 SITE DESCRIPTION AND HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3.0 CERCLA ACTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4.0 REMEDY, REMEDIAL ACTIONS, AND STATUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

5.0 ARARS REVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

LIST OF TABLES

4-1 REMEDY, REMEDIAL ACTIONS, AND STATUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

LIST OF FIGURES

2-1 EAGLE MINE SITE AND VICINITY MAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

p:\parmnt\general\reports\5yrrev.rpt 1

1.0 INTRODUCTION

Section 121(c) of the Comprehensive Environmental Response, Compensation, and Liability Act(CERCLA) requires a review of a remedial action no less often than each five years after the initiation ofsuch remedial action when a remedial action results in any hazardous substances, pollutants, orcontaminants remaining at a site. Section 300.430(f)(4)(ii) of the National Oil and Hazardous SubstancesPollution Contingency Plan (NCP) requires a review of a remedial action no less often than every five yearsafter the initiation of the selected remedial action when a remedial action results in hazardous substances,pollutants, or contaminants remaining at a site above levels that allow for unlimited use and unrestrictedexposure.

The purposes of a five year review are to confirm that a remedy as specified in the record of decision(ROD) and/or remedial design remains effective at protecting human health and the environment and toevaluate whether original cleanup levels remain protective of human health and the environment. For along-term remedial action, the review should focus on both the effectiveness of the technology, and on thespecific performance levels established in the ROD. A long-term remedial action is an ongoing remedialaction that has not yet achieved the cleanup standards. The remedial action at the Eagle Mine site is along-term remedial action.

Although the U.S. Environmental Protection Agency (EPA) retains final review and approval authority forthe five year review, EPA may authorize other parties to perform portions of the review through settlementagreements. Pursuant to Section VIII of the Eagle Mine Operable Unit Number 1 Partial Consent Decree,Civil Action No. 95-N-2360 (D. Colorado), EPA requested that Viacom International Inc. (Viacom)conduct the Document Review and Standards Review portions of the first five year review report for theEagle Mine site (Site). This Report contains the document review and standards review portions of a TypeI five year review report for the Site.

A Type I review is the most basic type of evaluation of protectiveness of the remedy and consists of thefollowing components:

• Document Review - includes review of ROD, consent decree, operation and maintenance (O&M)manual, monitoring plans, and monitoring data

• Standards Review - includes review of applicable or relevant and appropriate requirements(ARARs) specified in the ROD, and newly promulgated or modified federal and stateenvironmental laws to determine if they are applicable or relevant and appropriate for the site

p:\parmnt\general\reports\5yrrev.rpt 2

• Site Visit - includes a site inspection and interviews with state and local officials and people residingnear the site

• Report - includes discussions of remedial objectives, ARARs, and areas of noncompliance; astatement of protectiveness, and recommendations.

p:\parmnt\general\reports\5yrrev.rpt 3

2.0 SITE DESCRIPTION AND HISTORY

The Site is an abandoned mining and milling facility located along the Eagle River approximately five milessouth of Minturn, Colorado. The Site is located in areas of past mining activity between the Towns of RedCliff and Minturn. The Site includes the Eagle Mine workings, the Town of Gilman, the former mine tailingsponds, Rex Flats, and waste rock pile and roaster pile areas. Figure 2-1 is a map of the Site and vicinity.

Mining in the area was first conducted in the 1870s. Early in the 1900s several of the underground workingswere consolidated and orated as the Eagle Mine. In the early 1900s ores were processed by roasting andresidues from this process were disposed of in five “roaster piles,” three on the west side of the Eagle Riverand two on the east side. From approximately 1929 to 1931 and 1941 to 1946, ores were processed atan underground flotation mill at Belden. Mill tailings were slurried and conveyed down valley by gravity viaa pipeline and deposited at the Old Tailings Pile (OTP) and Rex Flats. The pipeline was extended furthernorth and from approximately 1946 to 1977, tailings were deposited at the New Tailings Pile. The NewTailings Pile is now known as the Consolidated Tailings Pile (CTP). Mining operations ceased at the EagleMine in 1984.

Figure 2-1

p:\parmnt\general\reports\5yrrev.rpt 5

3.0 CERCLA ACTIONS

The State of Colorado filed a complaint against Gulf & Western Industries, Inc. and New Jersey ZincCompany in 1983 for natural resource damages pursuant to CERCLA. The State conducted a RemedialInvestigation (RI) and Feasibility Study (FS) in 1985 and completed the RI and FS Reports in December1985.

In March 1986, EPA and the State entered into a Memorandum of Agreement (MOA) that designated theColorado Department of Health (now known as Colorado Department of Public Health and Environment(CDPHE)) as the lead agency. CDPHE issued its ROD for the Site on April 4, 1986. EPA listed the Siteon the National Priorities List on June 10, 1986.

The State of Colorado and Gulf + Western Inc. entered into a Consent Decree (CD) executed on June24, 1988 (Consent Decree, Order, Judgement and Reference to Special Master, Civil Action No. 83-C-2385). A Remedial Action Plan (CD/RAP) for the Site was part of the CD.

EPA began conducting a Feasibility Study Addendum (FSA) in September 1990 to evaluate the remedialactions that had been taken at the Site pursuant to the CD/RAP and to identify any additional remedialactions EPA determined were necessary to protect human health and the environment in accordance withCERCLA and the NCP. The FSA was completed in June 1992.

EPA issued a ROD on March 29, 1993. The 1993 ROD presents EPA’s selected remedy for OperableUnit 1 (OU-1) of the Site. OU-1 addresses the principal sources of mine waste at the Site. The principalsources are identified in the ROD as the Eagle Mine, the roaster pile area, waste rock piles, Rex Flats,OTP, CTP, and the Maloit Park wetlands. The remedial action described in the 1993 ROD is in additionto that required in the CD/RAP.

On July 7, 1994, EPA issued an Unilateral Administrative Order (UAO) for Remedial Design and RemedialAction, Docket No. CERCLA-VIII-94-19. In general, the UAO required Paramount CommunicationsInc. to submit work plans, sampling and analysis plans or reports for the following:

• Storm event/snowmelt surface water monitoring• Roaster pile spring monitoring• Belden area and CTP extraction trenches groundwater monitoring• Belden area waste rock pile sampling and analysis• Rock Creek seep collection system

p:\parmnt\general\reports\5yrrev.rpt 6

• CTP capping• Modification of the CTP groundwater extraction trenches• Evaluation, modification, and reconstruction of the CTP upgadient groundwater diversion trench

(UGDT)• Maloit Park wetlands.

EPA issued Amendment No. 1 to the UAO on May 30, 1995. UAO Amendment No. 1 requiredViacom to implement EPA-approved work plans developed pursuant to the UAO for the following:

• Storm event/snowmelt surface water monitoring• Roaster pile spring monitoring• Belden area groundwater monitoring• Maloit Park wetlands.

EPA and Viacom entered into the Partial Consent Decree for Eagle Mine Operable Unit 1, Civil ActionNo. 95-N-2360 (D. Colo.) on June 12, 1996. The 1996 Partial Consent Decree required Viacom tocomplete several response actions described in a Statement of Work (CD/SOW) attached to the PartialConsent Decree. The provisions of the 1986 MOA do not apply to the CD/SOW, although the Statecontinues to monitor remediation activities implemented pursuant to the CD/RAP.

p:\parmnt\general\reports\5yrrev.rpt 7

4.0 REMEDY, REMEDIAL ACTIONS, AND STATUS

According to the ROD, mining at the Site resulted in the deposition of about 8 to 10 million tons of minewaste and mill tailings along the Eagle River. Metals transported by mine drainage and seepage haveimpacted surface water and groundwater at the Site. The Site Water Treatment Plant (WTP) is also ofinterest because treated water is discharged to the Eagle River.

The ROD describes the remedial action objective (RAO) for each source area and specifies the remedialaction alternatives selected to achieve the RAO. Remedial design and remedial action activities requiredby EPA pursuant to the selected remedial action alternatives are specified in the UAO, Amendment No.1 to the UAO, and CD/SOW. The RAOs and a brief description of the remedy for each source area andthe WTP are provided on Table 4-1. The status of the remedial efforts is also provided.

Two additional remediation components identified in the ROD include the following:

• Develop and implement a Biological Monitoring Sampling and Analysis Plan to support a biologicalcriteria approach for evaluation and protection of the Eagle River at the Site and provide anevaluation of the effectiveness of remedial actions

• Develop and implement an Inspection and Maintenance Plan to specify all maintenance andinspection activities and responsibilities necessary to evaluate and ensure the continuedeffectiveness of response actions taken at the Site.

A draft Biological Monitoring Sampling and Analysis Plan (BMSAP) was submitted in December 1996and biological monitoring is conducted bi-annually. Biological monitoring activities include the following:

• Benthic invertebrate sampling• Density and diversity surveys of benthic invertebrates• Identification and evaluation of brown trout spawning habitat• Assisting the Colorado Division of Wildlife with fish population estimates.

Viacom, EPA, and CDPHE meet annually to discuss monitoring results and to refine the biologicalmonitoring program. Results of the biological monitoring program will be used to establish final remediationgoals for the Eagle River.

p:\parmnt\general\reports\5yrrev.rpt 8

A draft Inspection and Maintenance Plan was submitted in December 1996. Responses to CDPHE andEPA comments on the plan were submitted in June 1997. Inspection and maintenance activities arereported in the Annual Site Monitoring and Activity Reports.

A remedial action activity, specified in the CD/SOW, but not included on Table 4-1, includes developmentand implementation of a surface water sampling and analysis plan, and submittal of annual Eagle RiverWater Quality Reports. A Surface Water Sampling and Analysis Plan (SWSAP) was submitted inSeptember 1996. The Eagle River has been monitored regularly from 1989 to 1999. From 1989 to 1997,surface water sampling was conducted pursuant to the CD/RAP. Since May 1997, surface water samplinghas been conducted in accordance with the SWSAP. Monitoring results are reported in quarterly reports,Annual Eagle River Water Quality Reports, and Annual Site Monitoring and Activity Reports.

Table 4-1 Remedy, Remedial Actions, and Status

SourceSelected

RemedialAlternative

RemedialAction

Objective

Remedial DesignRemedial Action

ActivitiesPerformance Standard Status

CTP Drain and cap the historic pond.

Complete the CTP cap.

Dewater sludge generated at WTP anddispose of sludge in lined cell at CTP.

Continue extraction and treatment ofgroundwater from the north and eastextraction trenches.

Divert clean, upgradient groundwateraway from the CTP.

Install a new domestic well for the Townof Minturn.

Reduce the surface and groundwatertransport of metals so that finalremediation goals will be achieved in theEagle River.

Control potential human ingestion ofgroundwater from the CTP.

Control potential exposure pathway tomine tailings.

Control exposure to airbornecontaminants.

Complete the cap at the historic pondarea. If the CTP settlement criteria are notmet during the 1994 construction season,submit a report by December 1, 1994describing status of the capping effortand a schedule for completion. If the capis not completed by November 1, 1995,submit a second report by December 15,1995 to describing status of cappingefforts and schedule for completion.

Design and implement a Phase I workplan for CTP groundwater extractionsystem maintenance. Submit a Phase IIreport documenting results from Phase Iactivities and containingrecommendations, if any, for moremodifications. Submit an analysis of theperformance of the groundwaterextraction trenches each year in theAnnual Site Monitoring and ActivityReport.

Monitor the following piezometers toprovide data for potentiometric surfacemaps: ST-25A, ST-25B, NT-1, NT-2, ET-1, ET-2, and ET-3. Providepotentiometric maps and data regardingquantity of water extracted from thegroundwater extraction system inQuarterly Reports.

After completion of the CTP cap, monitorwater levels and groundwater quality atupgradient groundwater diversion trench(UGDT) wells DT-1 through DT-5.Integrate data with other CTP monitoringdata and submit potentiometric surfacemaps, UGDT well hydrographs, and anannual assessment of the UGDT to EPA.Assess the need to reopen or reconstructthe UGDT each year in the Annual SiteMonitoring and Activity Report.

Submit to EPA a map of existing deepmonitoring wells in Maloit Park and twogeologic cross sections of Maloit Park.Monitor Well ST-25 and provide data inQuarterly Reports and a statisticalassessment of the data in Annual SiteMonitoring and Activity Reports.

Completion of the CTP cap in the firstconstruction season followingattainment of settlement criteria.

Monitor peizometers until sufficient dataare gathered to assess effectiveness of theCTP groundwater extraction trenches inlowering the groundwater level in thevicinity of the trenches.

Implement improvements to the CTPgroundwater extraction trenches toimprove collection of groundwaterbeneath the CTP. Operate thegroundwater extraction system untilsurface water ARARs are met.

Monitor Well ST-25 to assess metalconcentrations in the deep aquifer inMaloit Park.

A CTP cap status report was submitted on December 1,1994. A report regarding Historic Pond settlement wassubmitted on June 2, 1995. Another report, including arevised cap design was submitted on December 19, 1995.The CTP cap was completed in stages as regrading and/orsettlement criteria were met, beginning with placement ofthe cap on the side slopes in 1990. The multi-layer CTPcap was completed in November 1996.

A sludge dewatering system began operation at the WTPin January 1994. Dewatering sludge has been placed in thesludge disposal cell since April 1995.

Maintenance activities were performed on the CTPgroundwater extraction system and modifications weremade during the 1995 and 1996 construction seasons inaccordance with the approved Work Plan for CTPGroundwater Extraction System Maintenance andTemporary Measures. Additional investigative activitieswere completed during the 1997 construction season. APhase II CTP Groundwater Extraction Trenches Report(December 15, 1997) documented completed activities andincluded an assessment of the effectiveness of theextraction system. An addendum to the Phase II report,submitted in March 1998, contained recommendations formodifications to the extraction system. Modifications areplanned in 1999 at the west end of the north groundwaterextraction trench.

Wells associated with the groundwater extraction systemand Wells ST-25 and ST-25A are regularly monitored anddata and potentiometric maps are provided in quarterlyreports. Groundwater extraction system water accountingand calculations are provided in quarterly reports.

Water levels and groundwater quality have been regularlymonitored at the UGDT wells and data have been reportedsince 1992. The UGDT was opened and a 90-day dischargetest was conducted in 1998. An assessment of thedischarge test results, reported in the 1998 Annual SiteMonitoring and Activity Report, indicated that it isbeneficial to operate the existing UGDT.

A map of deep monitoring wells in Maloit Park and twogeologic cross sections of Maloit Park were submitted in aletter dated September 10, 1996. Well ST-25 is routinelymonitored and data are reported quarterly. An assessmentof the deep aquifer is provided in the annual reports. Theassessment indicated that a releases from the CTP into thedeep aquifer in the Maloit Park area has not occurred.

A new domestic well was installed for the Town ofMinturn in November 1996.

Table 4-1 Remedy, Remedial Actions, and Status

SourceSelected

RemedialAlternative

RemedialAction

Objective

Remedial DesignRemedial Action

ActivitiesPerformance Standard Status

Roaster Piles Design and implement a program tomonitor the water quality of the springsemanating from the hillside below theformer Roaster Pile 1 area.

Expedite revegetation and monitorresults.

Reduce the surface water transport ofmetals from the area of Roaster Pile 1 andassociated drainage so that finalremediation goals will be achieved in theEagle River.

Re-establish vegetation to a naturalcondition.

Design and implement a plan to monitorthe specific conductance of springsemanating from the hillside below theRoaster Pile 1 area in the Roaster Piledrainage.

Prepare a revegetation monitoring planfor expedited revegetation in the RoasterPile drainage to ensure that correctivemeasures are implemented to achieverevegetation success.

Monitor the specific conductance of theRoaster Pile springs for a minimum oftwo years and until the actualcontribution of the Roaster Pile springsto specific conductance at Station T-6can be demonstrated.

Reclaimed area vegetation covercomprising a minimum of 50 percent ofthe appropriate reference area cover, withno one species comprising more than 80percent of the cover. Compliance withthis performance standard is targeted forthe end of the 1997 growing season.

Since 1995, specific conductance, temperature, and flowrate have been monitored twice a year at three springs inthe Roaster Pile drainage in accordance with the EPA-approved Roaster Pile Spring Monitoring Plan Eagle Mine,Minturn, Colorado (November 4, 1994). Results of themonitoring program are provided in Quarterly Reports andAnnual Site Monitoring and Activity Reports.

The Expedited Revegetation Monitoring Plan, Eagle MineSites (October 10, 1996) was approved by EPA. Annualmonitoring of revegetated areas in the Roaster Piledrainage indicate that the performance standard was met bythe end of the 1997 growing season. Monitoring resultsare provided in the Annual Site Monitoring and ActivityReports.

Rex Flats/OTP Areas Provide an alternate water supply iffuture development occurs.

Expedite revegetation and monitorresults.

Reduce the surface and groundwatertransport of metals so that the finalremediation goals will be achieved in theEagle River.

Prepare a revegetation monitoring planfor expedited revegetation in the RexFlats/OTP areas drainage to ensure thatcorrective measures are implemented toachieve revegetation success.

Reclaimed area vegetation covercomprising a minimum of 50 percent ofthe appropriate reference area cover, withno one species comprising more than 80percent of the cover. Compliance withthis performance standard is targeted forthe end of the 1997 growing season.

Annual monitoring of the revegetated Rex Flats/OTP areasindicate that the performance standard was met by the endof the 1997 growing season. However, portions of the RexFlats/OTP areas received vegetation treatments in 1998 inaccordance with the Expedited Revegetation MonitoringPlan, Eagle Mine Sites (October 10 1996). The vegetationtreatments were specified in a September 16, 1997memorandum to CDPHE/EPA and the plans were finalizedand approved by CDPHE in a memorandum dated October31, 1997. Monitoring results are provided in the AnnualSite Monitoring and Activity Reports.

Table 4-1 Remedy, Remedial Actions, and Status

SourceSelected

RemedialAlternative

RemedialAction

Objective

Remedial DesignRemedial Action

ActivitiesPerformance Standard Status

Waste Rock Piles/Belden Non-pointSources

Installation and sampling of monitoringwells near the toe of waste rock piles inBelden.

Storm water/snowmelt sampling toevaluate the metals loading to the EagleRiver attributable to the waste rock pilesin the Belden/Gilman area.

Leach testing of waste rock pile material.

Reduce the transport of metals byinfiltration and surface water runoff sothat final remediation goals will beachieved in the Eagle River.

Design and implement a waste rock pilerunoff sampling and analysis program toprovide data to characterize the natureand extent of snowmelt and storm watertransport of metals from the waste rockpiles to Eagle River.

Design, install, and monitor groundwatermonitoring wells in Belden.

Delineate the major waste rock piles.

Design and implement a waste rock pilesampling and analysis plan to assess thepotential release of metals from eachmajor waste rock pile. Analysis of thewaste rock pile samples should includecolumn leach testing.

Design and implement a waste rock pilesurface water runoff sampling andanalysis program to provide data thatadequately characterize snowmelt andstormwater runoff, and the associatedtransport of metals, if any, from the wasterock piles to the Eagle River.

Design and implement a waste rock pilesampling and analysis program toprovide data that adequately characterizethe nature and extent of the transport ofmetals via groundwater, if any, from thewaste rock piles to the Eagle River.

Assess the relative potential for each ofthe major waste rock piles to releasemetals to the environment upon exposureto precipitation and runoff.

An automatic storm event/snowmelt surface water runoffsampling program was initiated in July 1995 inaccordance with the EPA-approved StormEvent/Snowmelt Surface Water Runoff Monitoring Planfor the Belden/ Gilman Area, Eagle Mine Site (September15, 1995). Rainfall runoff sampling was conducted fromJuly through September 1995 and from May throughSeptember in 1996 and 1997. Snowmelt runoff samplingwas conducted during March and April 1996 and 1997.Results of these monitoring programs are provided inPreliminary Data Interpretation Report (PDIR) No. 3 -Belden Storm Event/Snowmelt Surface Water RunoffMonitoring (November 27, 1996) and Data EvaluationReport, Belden Area (December 1, 1997) (DER).

Four monitoring wells were installed in the Belden area inJuly 1995 in accordance with the EPA-approvedInstallation and Monitoring Plan for Belden GroundwaterMonitoring Wells Eagle Mine, Minturn, Colorado (June12, 1995). Water levels are measured and samples arecollected at the monitoring wells in conjunction with theSite-wide groundwater monitoring program. Initial resultsof the Belden area monitoring well sample program are provided in PDIR No. 2 - Belden Ground-WaterMonitoring Program (November 15, 1996) and the DER.

Aerial photographs of the Gilman and Belden areas takenin 1985 were reviewed to located and delineate the majorwaste rock piles. A field reconnaissance and mappingeffort was conducted in July 1996 to confirm the aerialextent of the piles delineated from the aerial photographs,to identify additional piles that required testing, and todetermine sample locations. The waste rock piles weresampled in August 1996 in accordance with the EPA-approved Work Plan for Waste Rock Pile Testing EagleMine, Minturn Colorado (September 15, 1995).Preliminary results of the waste rock testing program areprovided in a letter to EPA dated November 7, 1996. EPAagreed to eliminate the requirement of column leach testsin a letter dated February 12, 1997. Results of the wasterock testing program are integrated with results from thesnowmelt/surface water runoff and Belden well samplingprograms and are provided in the DER.

Table 4-1 Remedy, Remedial Actions, and Status

SourceSelected

RemedialAlternative

RemedialAction

Objective

Remedial DesignRemedial Action

ActivitiesPerformance Standard Status

Maloit Park Wetlands Excavate and remove contaminated soil,replace with imported fill and topsoil,and revegetate the area with wetlandstype vegetation.

Prevent direct contact exposures totailings or contaminated sediments in theMaloit Park Wetlands and re-establishvegetation to a more natural self-sustaining condition.

Install a fence around the Maloit Parkwetlands to limit access until the area isreclaimed.

Design and implement a work plan foruplands removal, fencing, andrestoration.

Propose a reference area for the uplands.

Design and implement a wetlandssampling and analysis plan.

Design and implement a work plan forwetlands removal and restoration.

Monitor upland and wetlandrevegetation success and provideanalysis of trends in Annual SiteMonitoring and Activity Reports.

Remove visibly contaminated materialand material which exceeds action levelsfor human health. Replace removedmaterial with fill material that willsupport establishment of wetlandsvegetation.

Re-establish a viable wetlandsvegetation community to a conditioncomparable to the reference area.Revegetation success will be determinedat the conclusion of the fifth growingseason after revegetation activities (i.e.,2001). Successful revegetation is definedas the reclaimed area having a minimumof 50 percent of the appropriate referencecover, with species similarity 50 percentof the reference cover. Final revegetationsuccess shall be attained at theconclusion of the ninth growing season(i.e., 2005). Final revegetation successwill be determined according to thecriteria set forth in the CD/RAP.

Conduct wetlands removal in a mannerthat minimizes the impacts to the waterquality of Cross Creek.

The Maloit Park upland soil removal was completed inAugust 1994 in accordance with the approved Work Planfor Maloit Park Upland Area Removal, Fencing andRestoration, and a fence was constructed around thewetlands area.

Maloit Park soils were sampled and analyzed in June 1995in accordance with the approved Maloit Park WetlandsFinal Sampling and Analysis Plan.

Soil removal and replacement activities and seeding ofselected areas were completed in 1995 in accordance withthe approved Work Plan for Maloit Park WetlandsRemoval and Restoration. Revegetation activities wereconducted at the wetlands in May and June 1996.Additional willow stakes were planted in the Maloit Parkwetlands in May and June 1997.

Vegetation monitoring began in 1995 at Maloit Parkreference areas, and began in 1996 at revegetated areas. Atthe conclusion of the 1998 growing season theperformance standard for vegetation cover was met, but theperformance standard for similarity was not met.Compliance with the performance standards is expected in2001. Results of vegetation monitoring are provided inAnnual Site Monitoring and Activity Reports.

WTP Continue to operate the WTP and dewaterand dispose of the sludge at the CTP.

Provide adequate capacity and treatmentperformance until such time that watertreatment is no longer required toconsistently achieve the final remediationgoals in the Eagle River.

Continue to operate the WTP.

Dewater and dispose of the sludge at theCTP.

Report discharge violations, operationalstatus, and sludge disposal activities inAnnual Site Monitoring and ActivityReports.

Provide capacity and treatmentperformance required to meet ColoradoDischarge Permit System permit limitsfor 10 years after the effective date of theConsent Decree or less if it can bedemonstrated that use of the WTP is nolonger needed to achieve ARARs at theSite.

A WTP has operated at the Site since 1990.

A sludge dewatering system began operation at the WTPin January 1994. Dewater sludge has been place in thesludge disposal cell since April 1995.

WTP activities are reported in Annual Site Monitoring andActivity Reports. WTP water accounting and calculationsare provided in quarterly reports.

Table 4-1 Remedy, Remedial Actions, and Status

SourceSelected

RemedialAlternative

RemedialAction

Objective

Remedial DesignRemedial Action

ActivitiesPerformance Standard Status

Eagle Mine Seepage Collection of prominent surface seeps inlower Rock Creek area and conveyance ofcollected water to WTP for treatment.

Collection of subsurface seepage in lowerRock Creek area and conveyance ofcollected water to WTP for treatment.

Diversion of surface water flow in RockCreek upstream of the impacted area.

Reduce transport of metals in both surfaceand subsurface mine seepage so that finalremediation goals will be achieved in theEagle River.

Design a seep collection system forlower Rock Creek area to reduce surfaceand subsurface seepage flow to the EagleRiver.

Continue Mine Drawdown (MDD)/siphon extraction system.

Conduct pump tests at the siphonextraction wells to evaluate average flowrates for one peak runoff period ( mid-April through mid-September) and onebase flow period (mid-Septemberthrough mid-April).

Complete a report that evaluates theeffectiveness of the MDD/siphonextraction system.

If MDD/siphon extraction system meetsthe performance standards, install electricpumps as a contingency extractionsystem in case the siphon is interrupted.

Extend the Rock Creek culvert abovemine seepage in the Rock Creek drainage.

1) Extract for treatment or eliminate 90percent of the subsurface seepage flowand collect or eliminate all surfaceseepage flow.

or

2) reduce metals transport so that waterquality in the Eagle River at Station E-11meets ARARs.

3) Convey base flow of Rock Creekabove mine seepage to existing RockCreek culvert.

Since 1990, surface seeps in the Rock Creek area have beencollected and piped to the WTP for treatment. To reducesurface and subsurface seepage, the MDD was initiated in1991 to lower the mine pool elevation. Mine water isreleased at the Adit No. 5 bulkhead and gravity drainedthrough pipelines to the WTP for treatment.

To collect subsurface seepage in colluvium in the lowerRock Creek area, extraction wells were installed acrosslower Rock Creek Canyon. Groundwater extraction bygravity siphon began in early 1993 and has continued on acontinuous basis since that time. Extracted groundwater isgravity drained through pipelines to the WTP fortreatment. Pump tests were conducted on May 18, 1994and September 27, 1994 to evaluate extraction well flowrates. The Final Rock Creek Extraction System Report,dated June 28, 1995, demonstrated the reliability andeffectiveness of the gravity siphon at reducing metal loadsto the Eagle River, and its ability to meet PerformanceStandard No. 1 EPA agreed that Performance Standard No.1 was being met in a letter dated June 30, 1998. Plans toinstall an electric pump in the siphon extraction well are inprogress.

Extension of the culvert above mine seepage in the RockCreek drainage was completed in November 1995 inaccordance with the EPA-approved Rock Creek CulvertExtension Design Basis (January 30, 1995).

p:\parmnt\general\reports\5yrrev.rpt 14

5.0 ARARS REVIEW

ARARs for the Site are divided into three types, contaminant specific, action specific, and location specific.Contaminant specific ARARs are germane to the development of objectives and goals. Action specific andlocation specific ARARs typically create constraints on the remedial actions. Therefore, contaminantspecific ARARs are the ARARs to consider in conjunction with the RAOs and the selected remedy.

ARARs and other to-be-considered information are described in the ROD. For surface water, EPA hasstated that the ARARs are the Colorado Table Value Standards for aquatic life (using a hardness of 100milligrams per liter); these standards are unchanged since issuance of the ROD. For groundwater theARARs are described as follows:

• Rex Flats - protection of surface water

• OTP - none identified

• Maloit Park north of Cross Creek - domestic use quality for arsenic, cadmium, chromium, lead,and mercury

• CTP - potentially usable quality for arsenic, cadmium, chromium, lead, and mercury

• Adjacent to Eagle River - protection of surface water.

Compared to the ARARs listed in the ROD, the standards that have been legislatively modified sinceissuance of the ROD are:

• Cadmium standard is 5 micrograms per liter (µg/L)

• Chromium standard is 100 µg/L.

PHOTOGRAPHS

Photographs provided by: Mr. Paul Osborne, Regional Hydrologist, EPAMr. Dick Parachini, River Basin Coordinator, CDPHEMr Gene Taylor, Remedial Project Manager, EPAMr Bob Neukirchner, Eagle Engineering ServicesMr. Terry Killingsworth, Dames & Moore

PART A - PHOTOGRAPHS

The photographs in this first section were taken of the Eagle Mine Site (1) priorto the beginning of the Superfund cleanup, and (2) during cleanup activities.

Poor Quality SourceDocument

The following document images

have been scanned from the best

available source copy.

To view the actual hard copy, contact the

Superfund Records Center at 303-312-6473

Aerial View of Beldon/Gilman area-Raoster Piles, 1985

Aerial view of OTP area – OTP formed bank of Eagle River prior to cleanup. 1985

Aerial View of CTP area-Prior to Cleanup. 1985

Waste rock piles near Belden. 1994. This pile notpart of the Eagle Mine Property.

Roaster Pile Gulch left side of picture. May 1984

Belden with waste rock piles on side slope.1994.

Roaster fine spillage from tram to Roaster PileGulch. May 1989.

Sediment collection basin Roaster Pile Gulch.August 1991.

Roaster fines in River looking downstream. May1989.

Lower part of Roaster Pile Gulch. Note red finesbeing removed. November 1989.

Eagle River at Rock Creek. September 1990.Note metals staining.

Eagle River at Rock Creek looking downstream.January 1995. Note low flow.

Eagle River looking upstream at Rock Creek.1989.

Eagle River at Rock Creek looking upstream.July 1996. Note higher flow.

Lining the old tailings line to carry water fromRock Creek and Eagle Mine. August 1986.

Old Tailings Pile and Rex Flats after removal. OldSlurry line with fiberglass liner. September 1996.

Old Tailing Piles and Rex Flats – slurry line ontrestle. May 1988.

CTP with cover. November 1989.

Historic pond area with geo-textile ready for fill.1994.

CTP November 1984 with historic pond.

Top of CTP with cover being placed. September1996.

Maloit Park – prior to cleanup. September 1995.

Maloit Park – after cleanup. November 1996.

Maloit Park – November 1996.

OTP removed – Considerable progress on CTP--Sludge cell constructed-Wetlands not remediated. Oct, 1994

CTP and Maloit Park-Cap near completion-Wetlands Cleanup finishedTreatment plant/Ponds/Sludge Pit. 1996

PART B – PHOTOGRAPHS

The photograph in this second section were taken of the Eagle Mine site in 1999after the completion of most cleanup activities described in the Five-year review.

PART C – PHOTOGRAPHS

The photograph in this third section were taken during the annual fishcounting in the Eagle River at the Eagle Mine Site in March, 2000.