Mine Site Description
The Le Du Hydraulic Mine Sluice Tunnel site is located on unpatented BLM administered land and California State Parks administered lands. It represents a mixed ownership site consisting patented hydraulic gold mine that is located near the southern boundary of Malakoff Mine State Park. The +20 acre mine site contains a 300+ foot long sluice box tunnel. Sampling of water, sediment, and biota within the tunnel or adjacent areas indicates that elevated concentrations of elemental and methyl mercury in the tunnel sediments and biota. Approximately 100 feet inside the tunnel a 5x5 foot shaft has been driven by miners during historic times. It is roughly 50 feet in height and represents a feeder shaft, which conveyed the gold-bearing surry of sand, mud, and silt to the sluicebox sets, which were constructed within the tunnel. At present, the outlet end of the sluice tunnel is partially blocked by rockfalls and has created several small seasonal pools that drain into the adjacent Humbug Creek. The wetlands areas are known to contain elevated levels methyl mercury in the water and biota. The sluice tunnel and the vertical feeder shaft represent physical safety concerns to the public. Dermal contact with the mine water discharge could pose a potential human health concern for recreational miners or park visitors. This project site shows excellent potential for cooperative mine restoration partnership involving BLM and California State Parks.
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