The Sulphur Bank Mercury Mine Superfund Site (SBMM) is located on the eastern shore of the Oaks Arm of Clear Lake (Oaks Arm), approximately 100 miles north of San Francisco. Action Memorandum Amendment 5 signed January 14, 1998 authorized the implementation of interim measures to minimize the impact of predicted extreme El Nino weather conditions at SBMM. It also stated that EPA was investigating temporary treatment technologies and attempting to gain approval from the California Regional Water Quality Control Board (RWQCB) to treat overflow from the flooded open pit mine, Herman Pit, prior to discharge to Clear Lake as an emergency measure. A subsequent action memorandum in 1999, Action Memorandum No. 6, addressed surface water controls to divert surface water runoff away from Herman Pit. This Action Memorandum Amendment is proposing a suitable and cost effective portable and temporary treatment technology that would greatly reduce acidity and concentrations of mercury, aluminum, sulfate and other contaminants of concern in the mine drainage.
