One of seven open adits along Thorne Gulch, a highly accessible area near a main access road in the Deadwood Mining District. Two of the adits are flooded but all are accessible for entry which presents a significant safety concern. All of the underground workings are on BLM administered land adjacent to the patented Brown Bear Mine. Downstream from the developed area the USGS sampled the water and creek sediments in an area containing relict fine, gray mine tailings. Sampling results are pending.
Previous/Existing Assessments
Locations and condition of all mine features were compiled in June, 2000. In August, stream water and sediment and mine tailings sampling was conducted and a final mine site characterization is pending.
Reclamation/Recommendations
No costs for remediation or removal actions have been estimated but the likely recommendation would be to close off the adit portals with gates or fill. If metal-laden sediment or contaminated water is, or could be, affecting the aquatic habitat additional actions would be required.
Risks: Water Quality, Physical Safety
AMLIS #: CA013600003
Location: N40 43 04, W122 43 52
Field Office: Redding
Congressional District: 02
Site Narrative
The Amy Balch Mine, according to historical records, was located on 4 unpatented claims in the Deadwood Mining District, probably around the turn of the century. A 1915 California Journal of Mines and Geology report describes the property as having a 540-foot tunnel , 1500 feet of drifts, a stope (50 feet by 3 feet by 90) and a 13-foot arrastre. No issues of water quality were apparent from initial measurements and observation but the results of more detailed sampling are pending. Because of the site's proximity to a main access road, and the accessibility of the workings the primary concern is human safety.
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