Elk Tunnel
San Juan County, Colorado
Elk Tunnel is an abandoned mine located on public land within the historic Animas Mining District near the town of Silverton, Colorado. The project was a component of a basin-wide reclamation effort designed to reduce metals contamination impacts to human health and the environment within the Upper Animas River Basin. Elk Tunnel was identified as one of the priority sites within the basin because drainage from the mine contributes significant metal loading to Cement Creek, a primary tributary to the Animas River.
The work performed for this project involved preparation of an EE/CA designed to address the human-health and ecological threats posed by water discharging from the collapsed adit at the mine and the engineering design required to implement the removal action selected to reduce metals concentrations in water discharging to the creek. The mine site was characterized based on information generated during previous investigations conducted within the Cement Creek drainage, including studies performed by the Colorado Water Quality Control Division, BLM, Colorado School of Mines, and Colorado Division of Minerals and Geology. Through the characterization effort, the metals identified as being of primary concern in the adit drainage included aluminum, iron, manganese, and zinc.
The removal action alternative selected on the basis of the EE/CA involved construction of an open channel in combination with three settling ponds. The alternative was designed to promote pH neutralization through limestone dissolution, provide aggressive aeration/oxidation through open channel segments, and maximize onsite storage capacity for the collection of metals precipitates. The action has been implemented at the mine and is currently providing passive treatment for reduction of metals in water discharging to the creek.
San Juan County, Colorado
Elk Tunnel is an abandoned mine located on public land within the historic Animas Mining District near the town of Silverton, Colorado. The project was a component of a basin-wide reclamation effort designed to reduce metals contamination impacts to human health and the environment within the Upper Animas River Basin. Elk Tunnel was identified as one of the priority sites within the basin because drainage from the mine contributes significant metal loading to Cement Creek, a primary tributary to the Animas River.
The work performed for this project involved preparation of an EE/CA designed to address the human-health and ecological threats posed by water discharging from the collapsed adit at the mine and the engineering design required to implement the removal action selected to reduce metals concentrations in water discharging to the creek. The mine site was characterized based on information generated during previous investigations conducted within the Cement Creek drainage, including studies performed by the Colorado Water Quality Control Division, BLM, Colorado School of Mines, and Colorado Division of Minerals and Geology. Through the characterization effort, the metals identified as being of primary concern in the adit drainage included aluminum, iron, manganese, and zinc.
The removal action alternative selected on the basis of the EE/CA involved construction of an open channel in combination with three settling ponds. The alternative was designed to promote pH neutralization through limestone dissolution, provide aggressive aeration/oxidation through open channel segments, and maximize onsite storage capacity for the collection of metals precipitates. The action has been implemented at the mine and is currently providing passive treatment for reduction of metals in water discharging to the creek.