The Harmony Mine is a former copper mine and milling facility, which operated between 1916 and 1931. The Site has been inactive since 1931. The property consists of approximately 330 acres of private patented land surrounded by the Salmon-Challis National Forest (SCNF), and includes a large tailings pile which lies approximately 1/3 on the private land and 2/3 within the SCNF. The Site tailings pile is at approximately 7,000 feet elevation. The South Fork of Withington Creek originates upstream of the tailings pile and flows through the remaining tailings pile. Withington Creek flows into the Lemhi River approximately 8 miles downstream of the Site. The Lemhi River flows an additional 10 miles to its confluence with the Salmon River.
The tailings pile is not contained and has partially collapsed into the stream channel. It appears that over one-half of the volume of material in the original tailings pile has been released, via failure of the tailings dam and stream erosion of the tailings pile. An estimated 10,000 to 20,000 cubic yards of tailings remain at the original tailings pile area. Tailings deposits are visible in the creek bed for up to 2.5 miles downstream of the tailings pile.
In August 2003, the Withington Creek forest fire destroyed almost all of the vegetative cover in the upper Withington Creek drainage at and above the Site. There has been one significant rain event in the drainage since the fire, which has already caused erosion and washouts in various locations around the mine Site. It is likely that any subsequent high intensity storm event or high volume runoff this coming Spring could result in massive failure of the remaining tailings pile.
EPA and USDA Forest Service are taking joint CERCLA Removal action to remove tailings and place into a secure repository approximately 1 mile from the mine site at a location on USFS admistered land.
