The Gilt Edge Mine Superfund Site (Site) is located in the northern Black Hills of South Dakota. The primary mine disturbance area covers approximately 360 acres. The Site is divided into three Operable Units (OUs). Operable Unit 1 (OU1) includes the acid rock drainage (ARD) sources within the primary mine disturbance area such as acid-generating waste rock and fills, spent ore, exposed acid-generating bedrock and sludge. Operable Unit 2 (OU2) includes collection and treatment, groundwater contamination, contaminant sources, surface water and sediments in the Strawberry Creek area. Operable Unit 3 (OU3) includes the Ruby Waste Rock Dump, which is one of the largest sources of ARD at the Site.

• Optimization Evaluation, Gilt Edge Mine Superfund Site Water Treatment Plant, Lawrence County, South Dakota (PDF)(59 pp, 4 MB, 2013, 542-R-13-002)