Nevada County Water Quality

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The Nevada County Board of Supervisors should request the following agencies to meet and confer to develop and implement a written agreement to define the responsibilities of each agency for the safeguarding of water quality in Nevada County: • US EPA, • State Water Resources Control Board, • California Department of Fish & Game, • California Department of Toxic Substance Control, • Nevada County Department of Environmental Health, • Nevada County Planning Department. This recommendation will not be implemented. Adequate definition of responsibilities and avenues for coordination and cooperation exist to safeguard water quality in Nevada County. The Nevada County Planning Department does not engage in water quality testing or analysis.

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Nevada County Board of Supervisors directs the Director of Community Development Agency to: • develop and implement policy and procedures for periodic testing of surface and ground water at the locations identified in this report and communicate the findings to the general public, • revisit and examine the lava Cap Mine incidents of 1979 and 1997 and develop and implement policy and procedures to ensure appropriate clean-up of such incidents, • develop and implement a plan for the immediate enforcement of the 1979 Clean Up and Abatement Order concerning the area below the lava Cap Mine. This recommendation will not be implemented. • Adequate testing of surface and ground water to insure the public health and welfare is currently conducted by appropriate State and Federal agencies. • Appropriate policies and procedures are currently in place at the Federal, State and Local level. • See comment in response to Finding 1 above. The remediation of the Banner/Lava Cap Mine is under the jurisdiction of the US EPA. , Sup~rfund Site Overview Lava Cap Mine, Pacific Southwest, US EPA .... hllp:llyosemile.epa.gov/r9lsfund/r9sfdocw .nsfNiewByEPA ID /CAD98361 8893 . " .. ..-:. EPA " (J - " : ~" I " " -" 1 01 ' '1 t, ;: . 1· ""~""" '-:'":;0 , r"f').'~-.;!. t~ Pacific Southwest, Region 9: Superfund SelVing Arizona, California, Hawaii, Nevada, Ihe Pacific Islands, and Tribal Nalions Lava Cap Mine ,7;>___ I On this page ! -~~'''.-. .'. , Bulletin 80ard EPA #: CAD983618893 '1 I . too-' Description and History Siale: Calilornta(CA) County: Nevada Links I NPL Listing History City: 5 miles SE of Nevada Cily I Congressional District: 02 NPL Status: Flnal Description Other Names: Proposed Date: 09/29/98 and Hisl!lli' FIIl,,1 Dale: 0 1/1 9/99 Deleted Dale: Mao this SIte in Cleanups In My Community Who is Involved The Lava Cap Mine site Investigation occupies approximately 33 and Cleanup acres in a semi-rural residential Activities area of the Sierra Nevada foothills in western Nevada Cleanup County, California. The site is Resu lts to approximately 5 miles Dti!f! POleFlliaUy southeasl of Nevada City and ResponSible 6 miles east of Grass Valley at Par1ies an elevation of about 2700 Documents feet. The site includes the and Reports Community mining area where ore was Involvement processed to recover gold, and areas where tailings which . Public originated at the mine have I Information been washed downstream and Repositories deposited over time. The ~ Additional downstream areas of the site I Unks include Lost Lake, a private Contacts Progress lake surrounded by homes, Profile (EPA located approximately 1-1/4 I Headquarters) miles downstream of the Lava Cap mine site. ~ In 1994, an estimated 1,776 people lived within one mile of the site, and 24,091 lived within four miles of the site. The immediate watershed basin ecosystem contains two California Species-of-Special-Interest: foothill yellow·legged frog and western pond turtle, in addition to more common species of reptiles, amphibians, fish, birds, and mammals. Gold and silver mining activities were initiated at Lava Cap Mine in 1861. From 1861 to 1918, processing of the ore and disposal of the waste rock, overburden, and tailings occurred off-site at the Banner Mine, which IS located approximately 1.5 miles north of the Lava Cap Mine. The Lava Cap Mine was inactive from 191 B to 1934, at which time mining activities were resumed and a flotation plant was tiuilt to process the ore at the site. The gold and silver concentrates from the flotation plant were shipped to two smellers, one in California and the other in Washington. In 1940, a cyanide plant was built to recover the concentrates on site. However, this operation proved to be relatively ineffective. From 1941 to 1943, the cyanide plant only handfed the middlings and tailings from the flotation plant. The middlings and tailings were ground to a very fine size (i.e., able to pass through a 400-mesh screen), then vat leached with cyanide to remove the residual gold and silver. Slurries from the flotation and cyanide processes were deposited in a ravine on the site. Where the ravine steepened and narrowed, a log dam approximately 60 feet high was built to hold the tailings in place. The waste rock and overburden were also deposited in two piles located at the site between the mineshaft and the tailings pond . In 1943, Lava Cap Mine was closed due to World War II. An attempt was made to re-open the mine in the mid-1980s. However, community opposition resulted in the defeat of a proposed re-zoning of the property which would have allowed mining activities to resume at the site. In 1979, complaints from local residents initiated an action from Calilornia's Central Valley Regional Water Quality Control Board (RWQCB) that led to issuance of a Cleanup and Abatement Order (CAO). The CAO called for the property owners at that time to take measures to limit tailings discharges to Lit1le Clipper Creek, to divert surface water runoH from the mine and mill waste fill deposits, and to obtain an evaluation of the dam. http://yosemite,epa.gov/r9/sfund/r9sfdocw.nsf/ViewByEPAID/CAD983618... 5/24/20 l4 Superfund Site Overview Lava Cap Mine, Pacitic Southwest, US b PA Page J ot 6 additional data are gathered and analyzed. The Interim Record of Decision can be found in the Technical Documents section, dated September 30, 2008. Initial Actions Initial response. In October 1997, the EPA Region 9 Emergency Response Office determined that conditions associated with the tailings release from the Lava Cap Mine site met the National Contingency Plan (NCP) section 300.415(b)(2) criteria for a removal action. During October and November 1997, 4,000 cubic yards of taitings were removed from the damaged dam area and stockpiled on the waste rock pile immediately to the north of the tailings pile The lower half of the dam (i.e., approximately 30 leet in height) was found to be in relatively good condition. The oversteepened slopes of the tailings pile immediately behind the dam were graded and the entire tailings pile was covered with waste rock. Stream diversions were also created around the tailings pile. In February 1998 a second response was constructed at Ihe site to stabilize another tailings release and to further improve the drainage. The removal action has been completed and included covering approximately 4,000 cubic yards of stockpiled tailings with a clay cap. Site Studies Remedial Investigation. As part of its longer term study of the site, EPA conducted several rounds of sampling upgradient f,om IIle mine, on the mine property, afong Little Clipper and Clipper Creeks in the stretch from approximately 2,000 feet upstream 01 the mine to approximately 1,000 feet downstream of Losl Lake, and from In and around Lost Lake. EPA sampled several media, including surlace soli, subsur1ace 501 1, air, groundwater, mine discharge, surface water, and sediment. To collect subsur'face soil and groundwater samples, EPA installed borings and constructed groundwater monitoring welis USing a truck-mounted drilling rig. Tho resutting remedial investigation report was released in November 2001. It concludes that arsenic in mine tailings is the primary threat to human health, while both arsenic and metals threaten the ecology of the area. A Remedial Investigalion for the Groundwater Operabfe Unit was completed in July 2008 and is avallablo in the information ropoSitorio(; for «)vi[Jw A supplement to this document may be developed once funher studies ot the groundwater/surface water interactions have been completed. SIte Studies Feasibitity Study. EPA distributed the public release draft of the Feasibility Study for the Mine Area in OU1 where mining took place in 2004 The feasibility study defined the goals of EPA's remedial action, evaluated different technologies for reaching those goals, and combined those available technologies into several alternative cleanup plans. Alternatives considered include: taking no action installing physical access and legal land use controls • decontaminating the mine buildings • demolishing the mine buildings • capping the tailings and waste rock piles and constructing surtace water diversion channels • excavating and disposing of the tailings and waste rock pile in an on-site landfill • excavating and shipping the tailings and waste rock pile to an off-site disposal facility • capping tailings and contaminated sediment in Little Clipper Creek down to Greenhorn Road • excavating the contaminated sedimet in Little Clipper Creek down to Greenhorn Road The Feasibility Study was completed for the drinking water component for Groundwater (OU2) in July 2008. Alternatives considered in this study include: • taking no action installing point-of-use undersink treatment units, land use notifications, and monitoring of groundwater installing wellhead treatment units, land use notifications, and monitoring at groundwater • providing an alternative water supply via pipeline from Nevada Irrigation District, land use notifications, and monitoring of groundwater The proposed plan is available now for the drinking water component of the Groundwater Operable Unit. A revised Feasibility Study and proposed cleanup alternatives for the Lost Lake Area (OU3) are expected in 2015. Cleanup Ongoing Construction. Mine Area Cap Construction of the cap on the mine area in OU1 has been essenlially completed. Excavated tailings and contaminated soils from LiHle Clipper Creek http://yosemite.epa.gov/r9/sfund/r9sfdocw.nsfNiewByEPAID/CAD9836 18.,. 5/24/2014 Superfund Site Overview Lava Cap Mine, Pacific Southwest, US EPA of6 11101/01 Final Human Health Risk Assessment --Lava Cap Mine Superfund Site 11 /01/01 Remedial lnvestigalion, Lava Cap Mine Superfund Site 11/01/01 Supporting data: Lava Cap Mine Remedial Investigation 02l01/04Public Release Draft Mine Area Feasibility Study 07/01 /080perable Unit 2 Feasibility Study Report 11 /01 / 10Remedial Action Report Mine Area Operable Unit (OUt) 09/ 14/ 11 First Five-Year Review Report Community Involvement Public Meetings; EPA is committed to involving the public in the cleanup decision-making process. Its Community Involvement Program focuses on answering the community's questions about the cleanup eHort, providing information to the community about site activities, and incorporating community issues and concerns into Agency decisions, particularly when a cleanup remedy is proposed. Community Involvement History: In November 2000, EPA held public meetings in Grass Valley and Nevada City on our preliminary results from initial rounds of sampling. In November 2001, EPA again held pubfic meetings in the same locations, in cooperation with the Lava Cap Mine Superfund Coalition, recipient of an EPA grant to provide technical expertise to the community in understanding the Lava Cap cleanup. At these meetings, EPA presented the results of its human health and ecological risk assessments. EPA also began a discussion with community members on their p