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Recovery Act Project Activity

Sulphur Bank Mercury Mine
Clearlake Oaks, CA

The Recovery Act funding will allow EPA to initiate the cleanup of mine wastes from the BIA 120 road in 2009.  The primary efforts in 2009 will be the performance of planning and coordination activities with the Elem Pomo Tribe, the procurement of a construction subcontractor, the initiation of work to provide temporary water supply, sewer service and access for EIC residents during the cleanup, and planning efforts to assure the early 2010 performance of mine waste excavation and disposal efforts, and reconstruction of BIA 120.

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The Sulphur Bank Mercury Mine (SBMM) Superfund Site is an inactive mercury mine that is located on a 200 acre property on the shores of Clear Lake in Lake County, California.  The SBMM property includes a flooded open pit mine and approximately 3,000,000 cubic yards of contaminated mine waste.  The Site also includes the contaminants that derive from SBMM that are now located in Clear Lake sediments, in the wetland to the north of the mine property, and at the Elem Indian Colony (EIC).   EPA is currently evaluating remedial actions for the main mine property and expects for issue a Record of Decision for this portion of the site in 2010.

The EIC is located on approximately 50 acres of land directly adjacent to SBMM that have been placed into Trust status for the Elem Pomo Tribe.  During construction of housing and the paved roadway system at the EIC in the 1970s, the U.S. Bureau of Indian Affairs (BIA) used mine waste from the SBMM as fill on residential lots located on the western edge of the EIC, as road base material on paved and unpaved roads throughout the EIC residential area, and as road base material for the only paved access road to the EIC.  High levels of mercury, arsenic and antimony are present in soils at the EIC and in the exposed roadway shoulders that exceed levels that are safe for residential and recreational use based upon EPA’s baseline risk assessment. 

In 2006 and 2007 EPA excavated and removed all mine wastes and contaminated soils that were located in the residential area at the EIC, and properly disposed of these contaminated materials in a secure location at the adjacent SBMM.   Because of limitations on funding at that time, EPA did not address the contaminated mine wastes that are present in the exposed roadway shoulders and beneath BIA 120.  EPA is performing this new removal action to address these contaminated mine wastes.

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