News.bytes Extra, issue 588
Response Action to Begin at the Descarga Tailings Impoundment Site
The Rand Historic Mining Complex (“RHMC”) is the subject of ongoing investigation by the Bureau of Land Management (“BLM”) to determine the nature and extent of contamination resulting from historic mining and milling activities in the area.* One of the areas being investigated in the RHMC is the Descarga Tailings Impoundment (“Descarga”), located on public land just a half-mile west of the old mining town of Randsburg near U.S. Highway 395, in Kern County.
|During its investigations, BLM has determined that the fine-grained mine tailings at Descarga have concentrations of arsenic that are orders of magnitude higher than risk-based screening levels established by the United States Environmental Protection Agency. In 2006, BLM re-routed OHV-access route R-110 away from Descarga and completed installation of fencing and signage to minimize access to areas of high levels of arsenic, while BLM conducted further investigation and developed a permanent solution to abate the human and ecological risks posed by exposure to arsenic in the tailings. |
|BLM has completed its investigation of the Descarga site and is now planning a phased cleanup of the site, beginning this summer. The first phase will address migration of windblown tailings accumulating outside of the fenced-off area. BLM will remove the tailings that have migrated beyond the fenced areas and stabilize the northwestern edge of Descarga (called the tailings “dam” due to its nearly 100-foot vertical drop), which is the primary source of the windblown tailings migrating off-site.|
|The initial phase of the cleanup is scheduled to be completed in September. In general, high-use times for the public to engage in recreational activities in the area, including use of OHVs, are fall and winter. As many as 30,000 visitors use the trails on weekends during this high season. BLM believes it is important, to the extent possible, to perform this cleanup while OHV activity is minimal, as Route R-110 will be closed during portions of the implementation. This will also minimize the impacts to businesses in the local economy.|
In early July, through a Memorandum of Agreement with the BLM, the US Army Corps of Engineers will remove and consolidate the windblown tailings outside of the fence, including from a portion of Route R-110, and begin re-contouring and stabilization of the dam. Windblown tailings on the hillside closest to Randsburg will be removed by using a vacuum system. This system minimizes harm to existing vegetation that would otherwise be lost if heavy equipment scraped the area. The collected tailings will then be deposited at the base of the dam where dust-prevention measures will include the application of water- and soil-applied polymers. In addition, a crushed concrete cap will be added to Route R-110 to minimize dust kicked up from vehicle use.
*BLM is the lead agency responsible for cleanup activities on public land at the Rand Historic Mining Complex, pursuant to its authority under the Comprehensive Environmental Response, Compensation, and Liability Act (“CERCLA”), the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), and the BLM CERCLA Response Actions Handbook (H-1703-1). Any questions regarding this project should be sent to Peter Graves at the BLM California State Office, 2800 Cottage Way, Suite W1623, Sacramento, CA 95825.
-- Sterling White, Abandoned Mine Lands, California Desert District Office (July 2013)
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