Site Narrative
The Blue Moon Mine is situated on a ridge east of the Merced River where general drainage from the site, but not necessarily from the mine, flows west about two miles into the river. The mine was primarily a zinc mine but produced appreciable amounts of copper, lead, gold and silver primarily from 1943 to 1947. By October, 1945 development consisted of a 500 foot hoisting shaft inclined 80 degrees west, drifts and crosscuts on five levels and a shaft 35 feet deep connected to the deeper workings by a winze. Development underground including shafts, drifts and crosscuts totals 2370 feet.
The primary concern at the site is acid drainage due to high-sulfur mine tailings and waste around the collar of the No. 2 shaft. Although drainage at the shaft is internal (into the shaft) iron-oxide stained seeps on the west side of the ridge are likely a product of mine water. Initial readings of the water seepage shows neutral pH and low to moderate conductivity, but metals may be present in solution. The water seeps are to be sampled in 2002 or 2003.
Previous/Existing Assessments
The locations and condition of mine features were compiled in 2000 initially by the CA DOC and again examined by BLM staff in the late summer. pH readings, collected by the DOC, from a leach test on mine tailings and waste indicated an acid producing environment. No water, other than an unrelated stock pond uphill, was observed at, or being released from, the site. Water and solid effluent, seeping from a hillside west of the site on private property, may be originating from, and affected by, the mine site uphill.
Estimated Costs
No costs for remediation or removal actions have been estimated but the likely recommendation would be to collect additional samples of mine waste for acid producing potential and analysis of metal content. Additionally, with the cooperation of private landholders, samples of water and solid effluent from the downhill seeps could be collected and analyzed.
Risk: Water Quality, Physical Safety
AMLIS #: CA02180010
Location: N37 33 58, W120 15 19
Field Office: Folsom
Congressional District: 19
>
