The Minnie Moore Mine produced about $7 million worth of silver ore between 1881 and 1887. In 1927, the mine was abandoned, buildings were dismantled, and equipment removed. In 1964, Federal Resources Corporation constructed a 250 tons per day flotation mill to reprocess tailings at the Site. Tailings reprocessing took place in 1964 and 1965. The Minnie Moore Mine Site presently consists of the 6-acre tailings pile, as well as the remains of the former mill and shop, and a still intact bunkhouse. The main tailings pile is located just south of the site entrance from Broadford Road. It lies on relatively level ground and rises about 20 feet above the original ground surface. The tailings pile is bordered on the east by Broadford Slough, which runs within five feet of the toe of the tailings pile in some places. Lead concentrations in an exposed 6-acre tailings pile at the Site range from 1,400 to 18,500 parts-per-million (ppm). Elevated concentrations of metals exist in nearby soils, including lead concentrations of 4,300 ppm at the former mill building area. The removal action includes the construction of a permanent clean cover for the tailings pile at the Minnie Moore Mine. Other nearby soils containing lead concentrations of 700 ppm or more will be removed and excavated areas will be backfilled with clean fill.
9/26/05: EPA OSC, ERRS and START contractors mobilized to site. Personnel on site: 1 EPA; 1 START contractor; 7 ERRS contractor. Equipment on site: 1 excavator 330; 1 front loader 938; 1 dozer D6; 1 haul truck 40-ton; 1 water truck. ERRS installed silt fence and began cutting side slope on east side of tailings pile (facing Broadford Slough) to 3:1. START contractor collected soils samples at nearby day care facility and on site around former mill and bunkhouse area.
9/27/05: Personnel and equipment on site same as 9/26/05. ERRS continued cutting and grading side slope on east side to north end of pile. START finished collecting soil samples (28 total) and ran samples using XRF metals analyzer. Five samples were selected to be sent for confirmatory laboratory analysis. START demobilized from site.
9/28/05: Personnel on site: 1 EPA, 8 ERRS contractor. Equipment on site: 2 excavator 330; 1 front loader 938; 2 dozer D6; 1 haul truck 40-ton; 1 water truck. Additional excavator and dozer delivered to site to speed work. ERRS began cutting side slope to 3:1 on northwest and northeast corners of tailings pile. Removed trees where necessary to achieve proper slope. ERRS began removing contaminated soils around former mill area for consolidation on tailings pile. EPA OSC interviewed with reporter and photographer from the Idaho Mountain Express local bi-weekly newspaper.
Continue shaping tailings pile to 3:1 side slopes and 10:1 crown. Continue excavating contaminated soils in former mill area and incorporate on tailings pile. Backfill excavated areas with clean soil. Place 2 foot clean soil cover on tailings pile. Revegetate tailings pile.
|
