The Gilt Edge mine site in the Black Hills has been declared a superfund site by the Environmental Protection Agency. The mine is an open pit cyanide heap leach gold mine that encountered sulfidic ore and waste during mining. The operator of the Mine became insolvent and abandoned the Mine to the State. The Mine was unreclaimed and included approximately 150 million gallons of acidic, heavy metal laden water in three open pits. The Mine continues to generate acid mine drainage.
EPA and the State Department of Environment and Natural Resources are currently conducting remedial actions on the Mine. The Attorney General is currently working with DENR, the United States Department of Justice, and EPA in pursuing contribution claims against potentially responsible parties.