Mine detail: Bunker Hill Mine

Previously called 'South Mayflower MineRanchoree MineRancheria Mine'

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Location

Lat / long: 38.42487, -120.8244

Resource(M)

Primary: Gold
Secondary: Silver
Ore: Gold, Pyrite, Arsenopyrite
Gangue: Quartz, Slate, Calcite
Orebody form: Tabular, pinch and swell
Discovery year: 1852

Production

Operation type: Underground
Deposit type: Hydrothermal vein
Development status: Past Producer

Geology

Host rock:Mariposa Formation
Host type:Slate,Greenstone
Structure:Melones Fault zone, Bear Mountains Fault zone, Melones Fault zone
Tectonic:Magmatic arc
Alteration processes:Wall rocks hydrothermally altered, having been partially to completely converted to ankerite, sericite, quartz, pyrite, arsenopyrite, chlorite, and albite. Locally, greenstone bodies adjacent to the quartz veins contain enough disseminated auriferous pyrite in large enough bodies to constitute low-grade ore.

References

DEP10310594
Reference{Deposit:: Carlson, D.W., and Clark, W.B., 1954, Mines and mineral resources of Amador County, California: California Journal of Mines and Geology, 50th Report of the State Mineralogist, p. 173.}{Deposit:: Clark, W.B., 1970, Gold districts of California: California Division of Mines and Geology Bulletin 193, p. 69-76.}{Deposit:: Duffield, W.A. and Sharp, R.V., 1975, Geology of the Sierra foothills melange and adjacent areas, Amador County, California: U.S. Geological Survey Professional Paper 827, 30 p.}{Deposit:: Knopf, A., 1929, The Mother Lode system of California: U. S. Geological Survey Professional Paper 157, 88 p.}{Deposit:: Koschmann, A.H., and Bergendahl, M.H., 1968, Principal Gold-Producing districts of the United States: U. S. Geological Survey Professional Paper 610, 283 p.}{Deposit:: Logan, C.A., 1921, Amador County, Bunker Hill Mine: California State Mining Bureau, 17th Report of the State Mineralogist, p. 408-409.}{Deposit:: Logan, C.A., 1927, Amador County, Bunker Hill Mine: California State Mining Bureau, 23rd Report of the State Mineralogist, p. 157-158.}{Deposit:: Logan, C.A., 1934, Mother Lode gold belt of California: California Division of Mines Bulletin 108, p. 72-74.}{Deposit:: Schweickert, R.A., Hanson, R.E., and Girty, G.H., 1999, Accretionary tectonics of the Western Sierra Nevada Metamorphic Belt in Wagner, D.L. and Graham, S.A., editors, Geologic field trips in northern California: California Division of Mines and Geology Special Publication 119, p. 33-79.}{Deposit:: Storms, W.H., 1900, The Mother Lode region of California: California Mining Bureau Bulletin 18, p. 80.}{Deposit:: Tucker, W.B., 1914, Amador County, Bunker Hill Mine: California State Mining Bureau, 14th Annual Report of the State Mineralogist, p. 20-22.}{Deposit:: McDougall, B.W., 1929, Preliminary report on the Original Amador and Bunker Hill Mines, Amador County, California: Unpublished report, 13 p.}{Deposit:: Zimmerman, J.E., 1983, The Geology and structural evolution of a portion of the Mother Lode Belt, Amador County, California: Unpublished M.S. thesis, University of Arizona, 138 p.}{Deposit:: Moore, L., 1968, Gold resources of the Mother Lode Belt, El Dorado, Amador, Calaveras, Tuolumne, and Mariposa counties, California: U.S. Bureau of Mines Technical Progress Report 5, p. 1-22}
ReporterDowney, Cameron (Higgins, Chris, T.), Schruben, Paul G.