Mine detail: Ruby Hill Gold Mine

Previously called 'West Archimedes DepositEast Archimedes resourceArchimedes Gold deposit'

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Location

Lat / long:

39.526, -115.9843

Resource(B)

Primary:	Gold
Secondary:	Silver
Tertiary:	Barium-Barite, Arsenic, Mercury, Antimony, Zinc
Ore:	Gold, Electrum, Limonite, Hematite, Pyrite, Cinnabar, Barite
Gangue:	Quartz
Orebody form:	The deposit shape is complex and irregular, but generally has a central elongate, subtabular body with ovate cross section. From this core, similar shaped lithologically controlled lobes branch and flare out along structural intersections.
Discovery year:	1991

Production

Operation type:	Surface
Deposit type:	sediment-hosted gold
Production size:	Small
Development status:	Producer
First production started:	1997

Geology

Host rock:	Goodwin Limestone, Pogonip Group, Ninemile Formation, Pogonip Group, Graveyard Flat porphyry, Antelope Valley Limestone, Pogonip Group
Host type:	Limestone,Porphyry,Chert
Structure:	Roberts Mountains Thrust; Central Nevada Fold Belt; Hoosac Thrust, The oldest identified structures within the deposit are the high-angle NNE-trending Bowman, ?271?, and Jackson pre-mineral faults that were important in localizing some gold mineralization. More common within the deposit are WNW-trending high angle structures including the Blanchard fault system, which largely controlled emplacement of the West Archimedes deposit, and the Molly fault system, which localized some gold mineralization and had up to 100m of post-mineral offset. E-W-trending normal faults localized base metal mineralization, and NNW-trending faults (such as the Holly and the ?150?) show significant post-mineral offsets, and may be associated with regional basin-and-range development.
Tectonic:	Central Nevada Fold Belt
Alteration processes:	Zones of silicification, jasperoid development, and limestone decalcification (decarbonization) guided ore formation.

References

MRDS	MP90056
DEP	10310484
Reference	{Deposit:: Dilles, P.A., Wright, W.A., Monteleone, S.E., Russell, K.D., Marlowe, K.E., Wood, R.A., and Margolis, J., 1996, The geology of the West Archimedes deposit: a new discovery in the Eureka mining district, Eureka County, Nevada, in Coyner, A.R., and Fahey, P.L., eds., Geology and Ore Deposits of the American Cordillera: Geological Society of Nevada Symposium Proceedings, 1995, Reno/Sparks, Nevada, v. 1, p. 159-171.}{Deposit:: Russell, K., 1996, West Archimedes Gold Deposit, in Green, S.M., and Struhsacker, E., eds., Geology and Ore Deposits of the American Cordillera: Geological Society of Nevada Field Trip Guidebook Compendium, 1995, Reno/Sparks, NV, p. 316-319.}{Deposit:: Sediment-hosted Gold Deposits of the Eureka (Ruby Hill Mine) and Gold Bar Districts, East-Central Nevada, Geological Society of Nevada Special Publication No., 27, 1998 Spring Field Trip Guidebook.}{Deposit:: NBMG MI-97}{Deposit:: Mining Engineering, Dec., 1994, Society for Mining, Metallurgy, and Exploration, Littleton, Co, vol. 46, p. 1320.}{Deposit:: Final Environmental Impact Statement for the Ruby Hill Project of Homestake Mining Company, January 1997.}{Deposit:: Homestake press release, 2/19/98}{Deposit:: Denver Mining Record, 12/3/97}{Deposit:: Northern Miner, 11/23/97}{Deposit:: Long, K.R., DeYoung, J.H., Jr., and Ludington, S.D., 1998, Significant deposits of gold, silver, copper, lead, and zinc in the United States: U.S. Geological Survey Open-File Report 90-206A, 33 p.; 98-206B. one 3.5 inch diskette.}
Reporter	Sachiko Tanikawa, La Pointe, D.D., Schruben, Paul G.