Reclamation of the Sunnyside Mine was a priority for SGC, and the Company spent $30 million on reclamation and remediation over 30 years, with a focus on improving water quality in the Animas River. The Silverton Caldera, where the Sunnyside Mine is located, is highly mineralized and acid rock drainage and poor water quality in the Animas River existed long before the advent of mining.
In 1996, SGC entered into a voluntary Consent Decree agreement with the State of Colorado to complete numerous reclamation activities in the area. A number of reclamation activities were on land never owned or operated by SGC. Part of the reclamation included the installation of engineered concrete bulkheads in the area, a practice that is often part of the best management practices for final mine closure.
The primary purpose of the engineered concrete bulkheads was to isolate the interior workings of the Sunnyside Mine, and to prevent water flow from the interior workings to the Animas Basin and surface connections. As was always expected, the installation of the bulkheads caused the local water table to return toward natural levels.
Without the action of SGC, metal levels in the Animas River, and the resulting impacts on aquatic life and the trout fishery downstream of Silverton, would undoubtedly be more adverse.
Sunnyside completed approximately 20 significant reclamation and remediation projects using a comprehensive watershed approach. These include:
All of SGC’s regulatory requirements were fulfilled and SGC is in compliance with its reclamation obligations. In 2003, SGC was released from liabilities after the work was inspected and approved by the relevant agencies. SGC closed the mine in accordance with the law, its permits and a State-approved Consent Decree.
SGC has been an active participant of the Animas River Stakeholders Group (ARSG), whose members includes the State of Colorado, EPA, local government and Trout Unlimited. The ARSG, working together with other groups including the San Juan Clean Water Coalition, has always sought to improve water quality in the Animas River and advance the understanding of the issues in this historical mining district and highly mineralized area to find the most efficient means of remediation.