Mine detail: Florida Canyon Gold Mine

Previously called 'Zortman ExtensionWest Trend OrebodyMadre VeinNortheast Trend'

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Location

Lat / long:

40.57933, -118.23931

Resource(B)

Primary:	Gold
Secondary:	Silver, Mercury, Kaolin
Tertiary:	Arsenic, Barium-Barite, Sulfur
Ore:	Gold, Electrum, Kaolinite
Gangue:	Quartz, Kaolinite, Alunite, Pyrite, Marcasite, Arsenopyrite, Hematite, Limonite, Goethite, Opal, Calcite, Barite, Sulfur, Cinnabar, Fluorite, Magnetite, Adularia

Production

Operation type:	Surface-Underground
Deposit type:	hot spring; hydrothermal stockwork/stringers
Production size:	Medium
Development status:	Producer
Production years:	1986 - Present (2004)
First production started:	1986
Last production ended:	2004

Geology

Host rock:	Grass Valley Formation
Host type:	Siltstone,Mudstone
Associated rock:	Limerick Greenstone, Rochester Rhyolite, Weaver Formation, Prida Formation, Natchez Pass Formation
Associated type:	Andesite,Rhyolite,Tuff,Dolomite,Limestone,Siltstone,Mafic Volcanic Rock
Structure:	Florida Canyon lies near the intersection of NE-oriented structures of the Midas Lineament and N-S trending Basin and Range normal faults. These deep-seated structures served as conduits for gold-bearing hydrothermal fluids. A strong N30-N50E structural fabric is present in and adjacent to the orebody as evidenced by alignment of quartz veining, shear zones, and well developed joint sets., North-trending anticlines related to Nevadan Orogeny; Basin and Range normal faulting.
Alteration processes:	Silicification, argillization, acid leaching. During Jurassic regional metamorphism, the three primary host lithologies underwent the following changes: 1) in the more siliceous units, quartz was locally recrystallized and feldspar fragments and interstitial clays were mostly converted to sericite, 2) the clay portion of shaley siltstones was altered to sericite while the quartz portion was largely unaffected, and 3) mudstones were converted to argillites consisting mostly of fine grained sericite. Tertiary hydrothermal alteration overprints pervasive metamorphically derived quartz-sericite and is most intense within and adjacent to shear zones and hydrothermal conduits and beneath impermeable rock units. The major hypogene minerals are quartz, kaolinite, and alunite. Quartz occurs as fracture filling, selective replacements of calcareous units, and as irregular flat-lying cryptocrystalline bodies. Hydrothermally altered argillaceous rocks are pervasively kaolinized, although more siliceous units have undergone only minor argillization. Supergene alunite and kaolinite have formed by the downward percolation of acid solutions along faults and fracture zones. These fracture zones often contain calcite, exotic hematite, goethite, and sparse native sulfur. Extensive surficial bleaching is also attributed to acid leaching in the secondary environment. Hematite derived from syngenetic sulfides was mobilized by acid solutions, resulting in a pervasive maroon stain in silty units marginal to bleached areas.

References

MRDS	M060319
DEP	10310409
Reference	{Deposit:: Johnson, M.G., 1977, Geology and Mineral Deposits of Pershing County, Nevada: NBMG Bull. 89}{Deposit:: Vanderburg, 1936, Reconnaissance of Mining Districts of Pershing Co., Nevada: USBM IC 6902}{Deposit:: Silberling and Wallace, 1967, Geologic Map of the Imlay Quad., Pershing Co., Nevada: USGS Map GQ666}{Deposit:: Hastings, J. S., Burkhart, T. H., and Richardson, R. E., 1988, Geology of the Florida Canyon Deposit, Pershing County, Nevada, in Schafer, R., et al., eds., Bulk Mineable Precious Metal Deposits of the Western United States, a Symposioum, The Geological Society of Nevada, Reno, p. 433-451.}{Deposit:: Pegasus Gold Corp., Annual Reports for 1985, 1986, 1987, 1989, 1990, 1991, 1994.}{Deposit:: Miller, B. W., 1984, The Florida Canyon Gold Deposit, in Slavik, G., ed., Special Publication No. 1, The Geological Society Of Nevada, Reno, P. 30-32.}{Deposit:: Bonham, H.F. Jr, and Hess, R. H., 1992, Bulk-Mineable Precious-Metal Deposits, in The Nevada Mineral Industry 1991, Nevada Bureau of Mines and Geology, Special Pub., MI-1991, p25}{Deposit:: Engineering and Mining Journal, June 1988, P45}{Deposit:: NBMG, 1994, MI-1993}{Deposit:: Nevada Division of Minerals, 1994}{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:: Preuss-Nicole-E; Fifarek-Richard-H; Thomason-Robert-E,1997, Hydrothermal and vapor-related alteration at the Florida Canyon epithermal gold deposit, Pershing County, Nevada, Abstracts with Programs - Geological Society of America. 29; 6, p. 207.}{Deposit:: NV. BUREAU OF MINES BULLETIN 89, 1977, PLATE 2A.}{Deposit:: PEGASUS GOLD CORP., OPERATING PLAN FOR THE FLORIDA CANYON PROJECT, 1985, 18 PP.}{Deposit:: PEGASUS GOLD INC, FORM 10K FOR 1989, 82 PP.}{Deposit:: PEGASUS GOLD INC, AMENDED PLAN OF OPERATIONS, APRIL 12, 1990}{Deposit:: NEV. DIV. MINE INSPECTION, 1991, DIRECTORY OF NEVADA MINE OPERATIONS ACTIVE DURING CALENDAR YEAR 1990, P. 78.}{Deposit:: AMERICAN MINEWS HANDBOOK, 1996, P188.}{Deposit:: RANDOL, 1996/1997, MINES DIRECTORY, US MINES AND MINING COMPANIES, P 244.}{Deposit:: NEVADA, MINES DIRECTORY, 1995/96, PP 15, 16, 28.}{Deposit:: PEGASUS GOLD INC., FORM 10-K, DEC., 31, 1994.}{Deposit:: PEAGSUS GOLD INC., FORM 10-K, DEC., 31, 1995.}{Deposit:: THE MINING RECORD, VOL. 106, #13, MARCH 29, 1995, P1}{Deposit:: THE MINING RECORD, VOL. 107, #34, AUG. 21, 1996, P19.}{Deposit:: THE MINING RECORD, VOL. 107, #??, SEPT. 4, 1996, P20.}{Deposit:: THE MINING RECORD, VOL. 107, #41, OCT., 9, 1996, P1.}{Deposit:: THE MINING RECORD, VOL. 107, #49, DEC., 4, 1996, PP. 8, 9.}{Deposit:: PEGASUS GOLD INC., NEWS RELEASE, OCT., 1, 1996.}{Deposit:: SKILLINGS MINING REVIEW, 10/5, 1996, P5.}{Deposit:: PEGASUS GOLD INC. NEW RELEASE, 10/1/96, 2 PP.}{Production:: RANDOL MINING DIRECTORY 1996-97, P.244.}{Reserve-Resource:: PEGASUS GOLD INC. FORM 10-K, DEC., 31, 1995, P9.}{Reserve-Resource:: PEGASUS GOLD INC., 1996 ANNUAL REPORT, PP. 6-7, 11 & 1996 FORM 10-K REPORT, PP. 8-11.}
Reporter	Johnson, Maureen G., Royse, Sue E., Berger, Mary A., Phinisey, J. D. (Marcus, S.), Marcus, Sue, Lowe, Nathan T., Li, Zhiping (Moyer, Lorre A.), Buckingham, David A., LaPointe, D.D., Schruben, Paul G.