Casino Mine

White Pine County, Nevada, United States

Gold

⌖ Show on map USGS source ↗

Description

Lyle Campbell

Commodities

PrimaryGold

Commodity typeM

Deposit

Deposit typesediment-hosted gold

Model173: Sediment-hosted Au

Deposit sizeS

Ore controlThe Casino deposit is localized along the edge of a fold. Whole-rock major, minor, and trace element analyses indicate that Au, Sb, and As are in general associated with the Keno fault zone, suggesting that Au- and silica-bearing fluids migrated along the fault to replace carbonate in the footwall and adjacent hanging wall rocks.

Materials

Ore mineralsGold

Geology

Host rockSiltstone,Limestone

Associated rockVolcanic Rock (Aphanitic)

StructureThe Bald Mountain district is located in an area of thinned crust along the eastern side of the Late Proterozoic rift that split the North American craton. It is also in the west-central portion of the Late Devonian-Early Mississippian Antler foreland basin, and near the eastern edge of deformation related to the late Paleozoic Humboldt orogeny To the west of the Bald Mountain district, geologic interpretations are dominated by recognition of Paleozoic deformation, whereas to the east, interpretations emphasize Mesozoic contraction and plutonism and Tertiary extension., The Casino pit contains one moderately dipping normal fault as well as multiple high- and low-angle faults. At Casino, northeast structures are present, accompanied by north- and west-trending structures. The Keno fault zone is a moderately dipping normal-fault zone in siltstone and silty limestone with 55-100 m of dip-slip displacement. The fault changes character along strike from a single clay-rich slip plane 10-20 mm thick at the northern exposure in the pit to numerous hydrocarbon-bearing, calcite-filled, nearly vertical slip planes in a zone 15 m wide at the southern exposure. The hanging wall and footwall are intensely fractured but fracture densities do not vary markedly with distance from the fault.

Tectonic settingThe Bald Mountain district is located in an area of thinned crust along the eastern side of the Late Proterozoic rift that split the North American craton. It is also in the west-central portion of the Late Devonian-Early Mississippian Antler foreland basin, and near the eastern edge of deformation related to the late Paleozoic Humboldt orogeny.

AlterationAlteration at the Casino Deposit includes decalcification, pervasive silicification, and argillization. Silicification and the formation of jasperoid are the dominant alteration types.

Economic & production

Development statusProducer

Production years1990-1992

First production1990

Last production1992

Identification

Deposit ID10310390

MRDS IDRE00279

Alternate namesKeno Pit

RegionNA

Data scoreA

Coordinates39.9682, -115.51528

References

USMX, 1990, Annual Report for 1989.USMX, 1992, Annual Report for 1991.Netcher, D. R., 1990, Environmental Assessment (EA-NV-040-90-03), USMX Inc., plan of operation for Casino Project Open Pit Mine.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.NBMG MI-88 through MI-02NBMG Map 91, 3rdCasino EA 1990Hitchborn and others, 1996, Geology and Gold Deposits of the Bald Mountain Mining District, White Pine County, Nevada, in Geology and Ore Deposits of the American Cordillera Symposium Proceedings, eds. A. Coyner and P. Fahey.The Geological Society of Nevada 1996 Spring Field trip, Geology and Gold Deposits of Eastern Nevada, GSN Special Publication No. 23.1996Casino EIS, 1995Nevada Land Status, 1990MASMILS 0320330520Amer. Mines (1990), 1990) thru Amer. Mines (2000), 1999.Nutt, C.J., Hofstra, A.H., Hart, K.S., and Mortensen, J.K., 2000, Structural setting and genesis of gold deposits in the Bald Mountain-Alligator Ridge area, east-central Nevada, in Cluer, J.K., Price, J.G., Struhsacker, E.M., Hardyman, R.F., and Morris, C.L., eds., Geology and Ore Deposits 2000: The Great Basin and Beyond: Geological Society of Nevada Symposium Proceedings, May 15-18, 2000, p. 513-537.Hammond, K. Jill and Evans, James P., 2003, Geochemistry, mineralization, structure, and permeability of a normal-fault zone, Casino Mine, Alligator Ridge district, north central Nevada; Journal of Structural Geology, vol.25, no.5, pp.717-736.BLM, 2004, Bald Mountain Mine Exploration Program Programmatic Environmental Assessment NV040-04-023, Case File # N78825.1991 ANNUAL PRODUCTION: USMX, 1992, ANNUAL REPORT FOR 1991. 1990-1991 CUMULATIVE PRODUCTION: USMX, 1992, ANNUAL REPORT FOR 1991.