Alligator Ridge Mine

White Pine County, Nevada, United States

GoldSilverAntimonyMercury

⌖ Show on map USGS source ↗

Description

Lyle F. Campbell

Commodities

PrimaryGold, Silver

TertiaryAntimony, Mercury

Commodity typeM

Deposit

Deposit typedisseminated, hydrothermal

Model173: Sediment-hosted Au

Deposit sizeL

WorkingsSurface

Orebody formdiscontinuous lenses

Ore controlStratigraphic controls: The greatest portion of precious metal mineralization occurs in the lower 300 feet of the Pilot Shale; a small portion of the mineralization is in the upper 25 feet of the underlying Devils Gate Limestone. This conformable sedimentary contact was the focus for lateral movement of hydrothermal fluids. The upper 100 feet of the pilot shale is a less permeable claystone and may have capped hydrothermal fluids. Structural controls: the Vantage fault served as a conduit for rising hydrothermal fluids. There is also evidence of a north-northeast striking asymmetrical anticline running the length of the deposits. The axis of the anticline would lie along the strike of the three vantage deposits and plunges gently to the southwest. Along the crest of the anticline numerous extensional fractures and extensive brecciation may have provided conduits for the ore-bearing solutions.

Materials

Ore mineralsGold

GangueQuartz, Barite, Calcite, Gypsum, Alunite, Kaolinite, Stibnite, Pyrite, Orpiment, Realgar, Jarosite, Hematite, Stibiconite, Goethite

Geology

Host rockSiltstone,Limestone · "Pilot Shale", "Devils Gate Limestone", "Joana Limestone"

Associated rockClaystone · Pilot Shale

StructureBasin and Range-type high angle normal faults. Low amplitude anticlines and synclines that strike N-S and plunge 20S, with limbs that dip nearly 20 degrees., N- to NE-striking normal fault ; possible N-NE striking anticline.

AlterationAlteration consists predominantly of quartz replacement of host rock carbonate. Quartz replacement in Pilot Shale closely follows the contact between ore and waste, whereas in Devils Gate Limestone, a stratiform jasperoid replacement body extends well beyond the ore zones. Beyond the area of silicification, diagenetic dolomite in Pilot Shale was replaced by hydrothermal calcite, and calcite veins comprised as much as 10% of the host rocks. Following gold deposition, intense oxidation destroyed organic matter, sulfides, and detrital illite in Pilot Shale and alunite and/or barite veins were deposited; this event is thought to be hydrothermal. Lastly, oxidation related to weathering deposited jarosite and goethite. Shifts in the isotopic compositions of carbonate are associated with gold mineralization.

Economic & production

Development statusProducer

Production years1981-1996

First production1981

Last production1996

Discovery year1976

Identification

Deposit ID10310371

MRDS IDM233775

Alternate namesVantage #1 Orebody, Vantage #2 orebody, Vantage #3 orebody, Vantage VO orebody, NBMG sample site 928, Gator, Luxe B, Luxe C/D, Luxe G, Luxe Saddle, Luxe Saddle Extension

RegionNA

Data scoreA

Coordinates39.7602, -115.51839

References

The Geological Society of Nevada 1996 Spring Field trip, Geology and Gold Deposits of Eastern Nevada, GSN Special Publication No. 23.Bentz, J., Jones, R. B., and Smith, P., 1981, Field Examination and Mine TourNBMG Map 84, 1983, Active Mines and Oil FieldsDivision of Mine Inspection, 1983, Directory of Nevada Mine Operations Active During Calendar Year 1983.Garside, L. J., 1981, Notes on field trip and tour of mine for Geological Society of Nevada, 26 Sept 1981.NBMG Mining District Files 323, Press ClippingsNBMG, 1988, NBMG MI-1987.Klessig, P.J., History and Geology of the Alligator Ridge Gold Mine, White Pine Co. NV: in GSN 1985 Field Trip Guidebook.Ilchik, R.P., 1991, Geology of the Vantage Gold Deposits, Alligator Ridge, Nevada, in Raines, G.L., Lisle, R.E., Schafer, R.W. and Wilkinson, W.H., Eds., Symposium Proceedings, Geology and Ore Deposits of the Great Basin, Geologic Society of Nevada and the U.S. Geological Survey, April 1-5, 1990, Vo. 2, p. 645-663.Garbrecht, D. A., Jones, S. K., and Slothower, G. 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