SFUND RECORDS CTR 2080235 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION IX 75 Hawthorne Street San Francisco, CA 94105 MEMORANDUM SUBJECT: Request for a Time-Critical Removal Action at the Blue Ledge Mine Site, Rogue River National Forest, Siskiyou County, California FROM: Harry Allen, On-Scene Coordinator Emergency Response Section (SFD-9-2) THROUGH: Peter Guria, Chief Emergency Response Section (SFD-9-2) TO: Daniel Meer, Chief Response, Planning & Assessment Branch (SFD-9) I. PURPOSE The purpose of this Action Memorandum is to obtain approval to spend up to $484,302 in total response costs to mitigate threats to human health and the environment posed by the presence of hazardous mine wastes at the Blue Ledge Mine Site, located approximately 3 miles south of Oregon, in Siskiyou County, California (the "Site"). The Action Memorandum would serve as approval for expenditures by EPA, as the lead technical agency, to take actions described herein to abate the imminent and substantial endangerment posed by hazardous substances at the Site. The proposed removal of hazardous substances would be taken pursuant to Section 104(a)(1) of the Comprehensive Environmental Response, Compensation and Liability Act ("CERCLA"), 42 U.S.C. § 9604(a)(1), and Section 300.415 of the National Oil and Hazardous Substances Pollution Contingency Plan ("NCP"), 40 C.F.R. § 300.415. II. SITE CONDITIONS AND BACKGROUND Site Status: Non-NPL Category of Removal: Time-Critical CERCLIS ID: CAN000906063 SITE ID: 09MM A. Site Description 1. Physical Location The Site is situated on patented private land within the Rogue River National Forest on United States Forest Service ("USFS") Road 1060. It is approximately 35 acres in size. The geographic coordinates of the Site are 41° 57' 36" N latitude and 123° 07' 51" W longitude in Township 3 S, Range 9 E, on the Dutch Creek, CA (7.5-minute) topographic quadrangle. See Figure 1 for a Site Location Map. 2. Site Characteristics The Site is approximately 4,800 feet above sea level on a north slope, in close proximity to the summit. The terrain is rugged and precipitous in some places. The mine workings penetrate steep slopes and rock outcroppings and honeycomb the ground beneath surface features. Approximately four residences that comprise the community of Joe Bar, California, are located 1 mile downstream of the Site. See Figure 2 for a Site Map. The Blue Ledge Mine was one of the largest mining operations ever undertaken in the southwestern Oregon area (Kramer 1999 in Environment International 2002). Over two miles of underground excavations and connections were developed to mine massive sulfide deposits rich in copper, zinc, gold and silver. Historically, the economic value of the mine lay in extraction of copper and zinc. Tailings and waste rock have been dumped onto the steep slopes of the Site; the disposal area can be viewed easily from USFS Road 1060. The waste pile may be as deep as 30 feet in some places and is estimated to be between 30,000 and 40,000 cubic yards in volume. Runoff from rainfall and snowmelt is very rapid and the potential for sheet and gully erosion is high. A stream course cuts down the mountainside through the waste pile. The stream is an unnamed tributary to Joe Creek. The tributary travels approximately 1,200 feet and descends 800 vertical feet to its confluence with Joe Creek. A log tailings dam, approximately 30 feet wide and 6 feet in height, intersects the stream course, preventing the tailings and waste rock from collapsing and blocking the tributary completely. Some waste material has already penetrated the dam. The dam shows signs of significant decay and is in danger of collapse. Stream flows do bypass the dam and surface water contact with the waste pile has resulted in acid mine drainage ("AMD") and acid rock drainage ("ARD") in the tributary. An orange discharge leaches from the pile into the tributary. In addition, precipitate or "yellow boy", and "ferricrete" indicative of AMD can be observed at the " f. J^ . i -t;. -r^-. -| i ., : l| a n '- t''i*i.[ "!i ' ! i, "i'fi ,, '^J'Colifortwa , '. '0 i Printed Com TOPO1 ©2000 NaJxaal OwfinpWc HoHinfii (wmr.topox»aO Ecology and Environment, Inc. TDD No.: 09-05-04-0004 July 2005 Project No.: 0563.01 RS Figure 1 Site Location Map Blue Ledge Mine Rogue River National Forest Siskiyou County, California « ecology & Emnranmont, Inc. GIS Departmonl Projurl *1275 056i 01RS \\BUFNT1\GIS\SariFroiid»i;o\BI»! Lixljo Mirio''Jviap5\M,XO\SludyAiajs mxd 07/13C005 Ecology and Environment Inc. TDD: 09-05-04-0004 July 2005 Figure 2 Project No: 1275.0563.01RS Site Map | j Study Area Blue Ledge Mine Rogue River National Forest Siskiyou County, California 100 200 confluence of the tributary and Joe Creek (see Attachment II for the Photograph Log). 3. Removal Site Evaluation U.S. EPA and the Superfund Technical Assessment and Response Team (START) conducted a Site screening event followed by a removal assessment at the Site. Screening samples were collected on May 4, 2005 to identify contaminants of concern ("COCs") and to determine the probable sample population statistics. Based on the analysis of these samples, START determined that eighteen soil sampling locations, and five locations were necessary to determine the true population mean and upper confidence limit. The primary COCs were identified as lead and arsenic. The assessment took place on July 25, 2005. START divided the pile into two study areas and conducted random systematic soil sampling of the tailings to meet two main objectives. First, the sampling results should determine whether the surficial Site contamination exceeds the action level and the Site specific background concentration. Eight surface soil samples were collected for this purpose. Second, the sampling results should determine if unweathered materials contained significant concentrations of the COCs. Eight subsurface soil samples were collected at 1 to 1.5 feet below ground surface for this purpose. All samples were analyzed for the primary COCs: lead and arsenic. Two surface and 2 subsurface soil samples were also analyzed for secondary COCs: cadmium, copper, iron, manganese, mercury, and zinc. Statistical analysis of sampling results determines whether wastes on the Site are likely to pose an excess health risk based on potential human exposure concentrations. Preliminary analytical data indicated that the mean and 95% upper confidence limit concentration for the sample population significantly exceeded health- based benchmarks (i.e., Region 9 Preliminary Remediation Goals ("PRG")) and background concentrations. Table 3.1 presents these results in brief. Table 3.1 - Summary of Selected Soil Sampling Results Mpan Upper Average Roil Confidence FPA Maximum Minimum Limit on Background Contaminant Cone, PRG Concentration Concentration Mean Concentration (mg/kg) (mg/kg) Cone. (mg/kg) (mg/kg) Lead 2,710 616 1,349 1,634 11.6 400 Arsenic 287 62.4 135 159 7.6 22 Source: ecology&environment, Inc, (START) preliminary sampling results, July 2005. Note: bolded results indicate that measured concentrations exceed applicable health-based benchmarks. EPA PRG - EPA's Preliminary Remediation Goal. 4. Release or Threatened Release into the Environment of a Hazardous Substance, or Pollutant or Contaminant Releases of waste rock and tailings material from the Site have occurred and are likely to increase significantly when the tailings dam eventually fails. Tailings and waste rock lost due to sheet and gully erosion are likely to contain high concentrations of heavy metals. Fine grained materials may be entrained by high stream flows and transported off Site by the tributary through Joe Creek, Elliot Creek and ultimately to the Applegate River. In addition, persons passing over contaminated Site soils may transport fine-grained contaminated materials via contact with shoes or clothing. These secondary transport mechanisms pose the threat of release of hazardous substances, albeit at low concentrations. Surface water sampling conducted by the USFS in September 2000, April 2001, and August 2001 documented releases of heavy metals, including cadmium, copper, iron, lead and zinc to the tributary stream and to Joe Creek. Selected results are presented in Table 4.1. Other heavy metals identified in the 2004 Preliminary Assessment/Site Inspection ("PA/SI") sampling event are also notable. The PA/SI report is included in the Administrative Record for the Site (see Attachment 1). It is believed that AMD, generated as water infiltrates the waste rock and tailings, has caused these metals to leach from the wastes to surface water. Concentrations of cadmium and copper-exceeded federal and state Maximum Contaminant Levels ("MCLs") both in the tributary and Joe Creek. Copper, iron, and zinc exceeded Federal secondary drinking water standards both in the tributary and Joe Creek. Concentrations of zinc in the tributary exceeded the federal MCL Goal. Concentrations of cadmium, copper, iron and zinc all exceeded applicable background (i.e., upstream) concentrations by greater than 3 times. Surface water samples collected from Elliott Creek in April 2001 illustrated dramatic increases in copper, and zinc concentrations after the confluence with Joe Creek. Although the measured concentrations do not exceed applicable drinking water standards, the concentrations exceed applicable background concentrations by greater than 3 times. This data suggests that the Site is releasing dissolved heavy metals to the Joe Creek and that these dissolved metals are being transported to Elliott Creek. Sampling results were also compared to Aquatic Life Criteria ("ALCs"). Cadmium, copper, and zinc concentrations exceeded their respective ALCs, at one or more sampling location, in all of the 3 sampling events. Table 4.1 - Selected Surface Water Sampling Results Contaminant Date Tributary Joe Creek Highest background MCL MCLG fc/g/L) &/9/L) (A/g/L) fo/9/L) (A/g/L) Cadmium April 2001, 40.3 15.6, 13.4 ND 5 NA August 2001 Copper April 2001, 6,990 2,990, ND 1300 1000 August 2001 1,830 (State) Zinc August 2001 6,800 NA 3.6 NA 5000 Source: Environment International 2002.