Mine detail: Cortez Gold Mine

Previously called 'Cortez Joint Venture Gold MineCortez Leach OperationCortez MineGarrison Mine'

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Location

Lat / long:

40.19158, -116.62593

Resource(M)

Primary:	Gold, Silver
Tertiary:	Mercury, Arsenic, Antimony
Ore:	Gold, Pyrite
Gangue:	Hematite, Goethite, Quartz, Clay
Orebody form:	Irregular; gold is localized where limestone was faulted, brecciated and folded along margin of Tertiary intrusive, gold is micron-to sub-micron-size.
Discovery year:	1966

Production

Operation type:	Surface
Deposit type:	DISSEMINATED; SEDIMENT-HOSTED
Production size:	Large
Development status:	Producer
Production years:	1969-1976, 1981-1983, 1988-1993
First production started:	1969
Last production ended:	1993

Geology

Host rock:	Roberts Mountain limestone, Wenban Limestone
Host type:	Limestone,Siltstone,Sandstone
Associated rock:	Mill Canyon quartz monzonite stock, Caetano Tuff
Associated type:	Porphyry,Quartz Monzonite,Andesite,Rhyolite
Structure:	The deposit occurs within the Cortez Window in the Roberts Mountain Thrust., The deposit lies within the Cortez Window of the Roberts Mountain Thrust (Cortez Range).
Tectonic:	Basin and Range
Alteration processes:	Host rocks have been decalcified, silicified, leached, bleached, argillized, and oxidized. This phase of low grade hydrothermal alteration occurred after intrusion of the porphyry sill, and removed most of the carbon. A decalcification halo extends into the host rock surrounding the mineralized area. Mineralization is associated with silicification.

References

MRDS	M232243
DEP	10310410
Reference	{Deposit:: Roberts, R.J. et al, (1967) Geology and Mineral Deposits of Eureka Co. Nev., N.B.M. Bull. 64}{Deposit:: Wells J.D., Stoiser, L.R., and Elliot, J.E., (1969) Geology and Geochemistry of the Cortez Gold Deposit, Economic Geology v. 64, p. 526}{Deposit:: Stager, H.K., (1977) Geology and Mineral Deposits of Lander Co., N.B. of M. Bull. 88}{Deposit:: Division of Mine Inspection, Dec. 1983, Directory of Nevada Mine Operations Active in Calendar Year 1983.}{Deposit:: NBMG, 1983, Map 84, Active Mines and Oil Fields.}{Deposit:: NBMG, 1983, Active Mines and Oil Fields, Map 84.}{Deposit:: Bentz, J. and Smith, P., 1982, Field Examination Report, July 12, 1982.}{Deposit:: Metal Market Consultants, Inc., 1987, Gold Situation Map}{Deposit:: Nevada Dept. of Minerals, 1993.95-2}{Deposit:: .Geological Society of Nevada 1997 Spring Field Trip: Geology and Ore Deposits of Northeastern Nevada, Special Publication No. 25}{Deposit:: Long, 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.}{Deposit:: Geology and Ore Deposits of the American Cordillera, Field Trip Guidebook Compendium of the April 1995 Geological Society of NevadaSymposium; 501 p.}{Deposit:: Gulf Resources 1971-1974, Placer Development 1975-1984 Annual Reports.}
Reporter	Weeks, Robert, Kirkham, Richard A., Zigler, Jan L., La Pointe, D.D. (Tingley, J.V.), Moyer, Lorre A. (Marcus, S.M.), Li, Zhiping (Moyer, Lorre A.), LaPointe, D. D., Schruben, Paul G.