Project Case Study: California

The Boston Hydraulic Gold Mine Sluice Tunnel Remediation Project was the first successful pilot mercury removal/recovery/recycling project undertaken in California. The Abandoned Mine Lands Team used innovative project remediation concepts during the Engineering Evaluation/Cost Analysis phase of the project and worked with team members to successfully implement and execute technological innovations and novel remediation solutions.

For more information on our California AML projects, visit the BLM California State Office AML Web site and the California AML Strategic Plan.

California Case Study: Boston Placer Mine

Location

• Red Dog, California
• This site was BLM California’s highest priority abandoned mine land (AML) site slated for cleanup in 2005. The 200-foot long sluice box tunnel contained high concentrations of elemental and methyl mercury in the tunnel sediments.

Risks

• The 40 acre mine site contains a 200 foot long sluice box tunnel containing high concentrations of elemental and methyl mercury in the tunnel sediments. The blocked inlet of the sluice tunnel created a small seasonal pond and wetland area which also contains high levels of methyl mercury in the water and biota. The sluice tunnel and several deep, vertical shafts presented a physical safety concern to the public.

Innovation

• By removing the mercury from mercury contaminated sediments using innovative methods, BLM was able to remove contaminated sediments from within the sluice tunnel and free mercury from the ecosystem. This action reduced the site as a pollution “point source” and its subsequent transport of mercury and methyl mercury into the watershed.

Partnering and Cooperative Conservation

• There was widespread support for this project from interagency Federal partners (U.S. Forest Service, Bureau of Reclamation, U.S. Army Corps of Engineers, and U.S. Environmental Protection Agency), State Partners (California Department of Conservation Abandoned Mine Land Unit, California State Water Control Board, Central Valley Regional Water Quality Control Board, and California Department of Fish and Game), Local Partners (Nevada County Department of Environmental Health, and Nevada County Resource Conservation District), and numerous private landowner watershed stakeholders.