TWO-YEAR SULFATE REDUCING BIOREACTOR PILOT TEST RESULTS AT THE GOLINSKY MINE, CALIFORNIA 1

The Golinsky site is a small underground copper mine complex consisting of abandoned mine workings and remnants of smelter operations located on a steep hillside above Little Backbone Creek, a tributary to Lake Shasta. The mine pool is typical acidic mining influenced water (MIW) with a pH of 2.5 to 4 containing heavy metals including Fe, Al, Cu, Zn, Cd, and Mn. The US Forest Service committed to a bench and pilot scale testing program to demonstrate that the SRBR technology would work at the remote site and reduce metal loading on Lake Shasta. A pilot scale SRBR test system was constructed in 2004 and decommissioned in September, 2006 after 26 months of year-round operation. Despite overloading and other operational challenges (e.g., the site is only accessible by boat), the pilot system performed as expected. At the conclusion of the pilot test run, the pilot scale effluent was field-titrated with raw MIW. The results of this effort suggest that SRBR-treated MIW has geochemical benefits beyond the expected straight dilution effects. That is, the elevated alkalinity and sulfide concentrations of the SRBR effluent appear to be capable of providing additional treatment of raw MIW in a simple mixing and settling operation. The titrated mixtures were also tested for toxicity using MetPLATE™ testing kits. A first-phase treatment module is being designed based on the pilot test results.