ABSTRACT
ABSTRACT: A historic underground gold mine in the Sierra Nevada Mountains of central California was re-opened as an open-pit surface mine and operated for several years until the ore body was mined-out. A mine closure plan was submitted and accepted by regulatory agencies followed by extensive reclamation of all site features except the mill tailings pile. The mine owners developed an alternate capping plan based on performance criteria, but the revised plan was not initially accepted by the state. As a result of delays the entire mine site was re-examined. Concerns re-addressed included off-site migration of dissolved metals in groundwater, stormwater sediment transport, the formation of a pit lake containing dissolved constituents, and other complex issues. Reclamation is now in progress following negotiated closure specifications.
