This report summarizes the findings of an extensive treatability study of three stabilization technologies for mercury immobilization on materials collected from the Sulfur Bank Mercury Mine (SBMM), located north of San Francisco, in Lake County, California. The SBMM site is believed to be contaminating the adjacent Clear Lake environment with mercury derived from historic mining practices at the site. The study was conducted as a joint effort between EPA's Superfund Innovative Technology Evaluation (SITE) Program and the Mine Waste Technology Program (MWTP). Two mercury contaminated materials were selected for treatment by three types of stabilization technologies. The purpose of the study was to determine the effectiveness of the three stabilization technologies for immobilizing mercury in the waste rock materials and therefore reducing leachable mobile mercury in the effluent. Several mercury-bearing materials from the site were considered for testing. A material with high levels of leachable mercury was selected as the primary target of the study, and is referred to as 'Mercury Ore'. As a secondary objective, treatment effectiveness was evaluated on material that was lower in mercury concentration, but present in large quantities and is referred to as 'Waste Rock'.