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 tailings pile of approximately 10,000 cubic yards, which lies approximately 1/3 on the private land and 2/3 within the SCNF. The Site is at approximately 7,000 feet elevation. The South Fork of Withington Creek originates upstream of the tailings pile and flows through the existing tailings pile. Withington Creek flows into the Lemhi River approximately 8 miles downstream of the Site.
In August 2003, the Withington Creek forest fire destroyed 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 would have resulted in massive failure of the remaining tailings pile.
EPA and the USDA Forest Service are taking joint CERCLA Removal action to remove the existing tailings pile to a secure repository approximately 1 mile below the mine site on land admistered by the Forest Service. Approval was provided by the USFS for siting of the repository on USFS administered land. On September 19, 2003, EPA contractor personnel, under direction of the EPA OSC, began mobilizing to the Site to begin this work.
10/3 to 10/20
Personnel on site (except for Sundays):
EPA OSC - 1
FS OSC - 1
START Project Engineer - 1
ERRS contractor - 10
Completed hauling of tailings from mine site to repository. Final volume of tailings in repository (compacted and prior to placement of rock cover) is approximately 10,000 cubic yards, based on USFS survey. Completed placement of rock cover on repository, including 2 feet of compacted rock and an additional 1 foot average of uncompacted course and durable rock. Completed placement of woody debris on repository and other disturbed areas. Completed grading of original tailings pile area to conform with natural grade, and reconstuction of hydrologically stable creek channel through original tailings pile area. Completed construction of basin above reconstructed creek channel to intercept possible debris flow. Completed construction of interception trench to south and east sides of repository, to intercept and divert around repository potential run-on from precipitation and snow melt. Completed out-sloping and installation of water bars on all constructed or improved haul roads. Began demobilization of equipment and personnel. Began seeding of disturbed areas.
Finish seeding of disturbed areas. Demobilize all remaining equipment and personnel from Site. All Site work will be completed by 10/24/03.
EPA OSC to calculate final costs, and EPA and USFS OSCs to document cost share between EPA and USFS. Cost split will be based on surface area of original tailings pile, with 31% of tailings pile surface area on private lands, and 69% on USFS administered lands. It is expected that the funding already provided by the USFS and services in kind, including the value of the permanent repository on USFS administered lands, will approximately match an equatable cost share.
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