Nevada · Nye County
Producer

Round Mountain Gold Mine

Nye County, Nevada, United States
GoldSilverArsenicAntimonyThalliumMercuryMolybdenumFluorine-FluoriteManganeseTungsten
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Description

John Stebbins and Frank Dixon

Commodities
PrimaryGold, Silver
TertiaryArsenic, Antimony, Thallium, Mercury, Molybdenum, Fluorine-Fluorite, Manganese, Tungsten
Commodity typeB
Deposit
Deposit typedisseminations; veins; sheeted zones
Model104: Hot-spring Au-Ag
Deposit sizeM
Orebody formtabular, mushroom
Ore controlThere is a ring fracture zone associated with a buried caldera. Gold deposition is controlled by high-angle fractures, particularly the NW-trending sets. Fractures were reactivated by NW-trending strike-slip faulting.
Materials
Ore mineralsGold, Electrum, Pyrite, Quartz, Adularia, Sericite, Hematite, Limonite, Alunite, Jarosite, Illite, Montmorillonite, Kaolinite, Fluorite, Realgar, Scorodite
GangueClay
Geology
Host rockAsh-Flow Tuff,Metasedimentary Rock
Associated rockGranite · Shoshone granite pluton
StructureNW lineament is seen as a disruption in N-S trends of Toquima and Toiyabe Ranges, Northwest-striking faults and joints; a WNW-trending paleotopographic high, may represent the margin of buried caldera located SW of Round Mountain.
AlterationPropylitization and argillization of host rocks are intense. Adularia replacement of K-feldspars and plagioclase is associated with ore. Plagioclase and groundmass are replaced with quartz and sericite. Within propylitically altered rock, biotite is partially or wholly altered to chlorite. Groundmass is altered to chlorite +/- clay +/- carbonate+/- epidote. Plagioclase phenocrysts are altered to sericite (illite) as small points, clots, and veinlets along cleavage planes. Argillically altered rock contains no unaltered biotite or plagioclase, both phases being altered to clay (illite, montmorillonite, kaolinite) and sericite. Groundmass is entirely composed of fine-grained clays and sericite. Quartz-adularia silicification is widespread along the veins. Degree of silicification, sericite + argillic alteration increases with (higher) elevation. Fine-grained secondary quartz has replaced original plagioclase feldspars, occurs as clots in the groundmass, and as hairline veinlets that lace the rock.
Economic & production
Development statusProducer
Production years1906-1942; 1977-present (2005)
First production1906
Discovery year1906
Identification
Deposit ID10310392
MRDS IDM321740
Alternate namesSunnyside Mine, Sphinx Glory Hole, Great Western Tunnel, Rattlesnake, Keane Vein, Los Gazabo Vein
RegionNA
Data scoreA
Coordinates38.70382, -117.07814
References
Ransome, F.L., 1909, Round Mountain: U.S. Geological Survey Bulletin 380, p. 44-47.Kleinhampl, F.J., and Ziony, J.I.,19854, Mineral Resources of Northern Nye Co.: Nevada Bureau of Mines and Geology, Bulletin 99b.Ferguson, H.G., 1921, Round Mountain District: U.S. Geological Survey Bulletin 725-I, p. 383-406.Berger, B.R., Tingley, J.V., Filipek, L.H., and Neighbor, J., Processes controlling trace-element patterns in hot springs-related gold-silver deposits in late Oligocene volcanic rocks, Round Mountain, Nevada: unpublished report, Nevada Bureau of Mines and Geology Files.Skillings, D.N., Jr., Skillings Mining Review, March 3, 1979, p. 8-17.Silberman, M.L., Shawe, D.R., Koski, R.A., and Goddard, B.B., 1975, K-Ar ages of mineralization at Round Mountain and Manhattan, Nye County, Nevada: Isochron West, vol. no. 13, p. 1-2.Wall Street Journal, 1982, January 5, 1982, "Louisiana Land Boosts Estimates of Gold Reserves."Nevada Bureau of Mines and Geology MI-1987-2004.GSN Precious Metals Symposium, 1987, Fieldtrip Guidebook, p. 130; Technical Volume, p. 375.Mining Journal, Montagu Mining Finance, Mining Database, 8/10/91.Tingley, J.V., and Berger, B.R., 1985, Lode-gold deposits of Round Mountain, Nevada: Nevada Bureau of Mines and Geology Bulletin 100, 62 p.Cavender, W.S., and Purdy, C.P., 1985, The Making of the Round Mountain Mine, in Hollister, V.F., Ed., Discoveries of Epithermal Precious Metal Deposits, Society of Mining Engineers of AIME, New York, p. 101-104.Mills, B.A., 1985, Geology of the Round Mountain Gold Deposit: Nye County, Nevada, in Hollister, V.F., Ed., Discoveries of Epithermal Precious Metal Deposits, Society of Mining Engineers of AIME, New York, p. 104-114.Sander, M., and Einaudi, M., 1987, The Round Mountain Gold-Silver Mine, Nye County, Nevada, in Johnson, J., Ed., Bulk Mineable Precious Metal Deposits-Guidebook for Field Trips, the Geological Society of Nevada, Reno, p. 130-135.Argall, G.O., 1985, Heap Leaching Smoky Valley Gold, Engineering and Mining Journal, vol. 186, no. 12, p. 18-23.Sander, M., 1988, Geologic setting and the relation of epithermal gold-silver mineralization to wall rock alteration at the Round Mountain Mine, Nye County, Nevada, in Schafer, R., Et Al, Eds., Bulk Mineable Precious Metal Deposits of the Western United States, the Geological Society of Nevada, Reno, p. 375-416.Ferguson, H.G., and Cathcart, S.H., 1954, Geology of the Round Mountain Quad., Nevada: U.S. Geological Survey Geological Quadrangle Map Gq-40.Koschmann, A.H., and Bergendahl, M.H., 1968, Principal Gold Producing Districts of the United States: U.S. Geological Survey Professional Paper 610, p. 193-194.Echo Bay Mines Ltd., 1988, Annual Report Form 10-K For 1987.Echo Bay Mines 1993 Annual ReportNevada Dept. of Minerals, 1994Long, K.R., DeYoung, J.H., Jr., and Ludington, S.D., 1998, Database of significant deposits of gold, silver, copper, lead, and zinc in the United States; Part A, Database description and analysis; part B, Digital database: U.S. Geological Survey Open-File Report 98-206, 33 p., one 3.5 inch diskette.David L. Emmons, Kinross Gold Company, 2006, Geology of the Round Mountain Gold Deposit, Nye County, Nevada; GSN meeting presentation - October, 2006, abstract.