LJ Ridge Deposit

Site Name

Primary: LJ Ridge Deposit
Secondary: Bald Mountain Mine Project

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Commodity

Primary: Gold
Primary: Silver
Tertiary: Arsenic
Tertiary: Antimony
Tertiary: Mercury
Tertiary: Bismuth
Tertiary: Tellurium
Tertiary: Copper
Tertiary: Zinc

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Location

State: Nevada
County: White Pine
District: Bald Mountain District

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Land Status

Land ownership: BLM Administrative Area
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.
Administrative Organization: Ely BLM district

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Holdings

Not available

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Workings

Not available

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Ownership

Owner Name: Barrick Gold Corp.
Info Year: 2006

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Production

Not available

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Deposit

Record Type: Site
Operation Category: Producer
Deposit Type: sediment-hosted gold
Operation Type: Surface
Year First Production: 1983
Year Last Production: 2000
Years of Production:
Organization:
Significant: Y
Deposit Size: M

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Physiography

Not available

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Mineral Deposit Model

Model Name: Distal disseminated Ag-Au

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Orebody

Form: tabular to irregular.

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Structure

Type: R
Description: The 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.

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Alterations

Alteration Type: L
Alteration Text: Alteration consists predominantly of silicification, argillization, and potassic alteration.

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Rocks

Name: Quartz Monzonite
Role: Associated
Age Type: Associated Rock
Age in Years: 159.000000+-
Age Young: Late Jurassic

Name: Limestone
Role: Host
Age Type: Host Rock
Age Young: Late Cambrian

Name: Shale
Role: Host
Description: calcareous
Age Type: Host Rock
Age Young: Late Cambrian

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Analytical Data

Not available

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Materials

Ore: Gold
Gangue: Quartz
Gangue: Pyrite
Gangue: Arsenopyrite
Gangue: Sericite
Gangue: Sphalerite
Gangue: Chalcopyrite
Gangue: Tetrahedrite
Gangue: Galena

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Comments

Comment (Geology): Alteration comments: silicification, argillization, potassic alteration. The main alteration feature at Bald Mountain is the large halo of silicification and strong argillization. Potassic alteration is recognized at depth. Geology comments: Host rocks are calcareous shales and dark gray limestones which weather to iron-oxide stained red-brown-maroon and tan colors. Granitic intrusive with quartz phenocrysts and oxidized pyrite was noted in cut face of drill roads. Sulfur isotope studies indicate that ore fluids that formed the LJ Ridge deposit ere derived from the central part of the Bald Mountain stockigneous system.

Comment (Identification): This new record covers the LJ Ridge area of the Bald Mountain Mine project, which lies a mile east of the Pit 1-5 mine area.

Comment (Location): The LJ Ridge mine area of the Bald Mountain Mine project lies on the west flank of Big Bald Mountain about a mile east of the Pit 1-5 mine area.

Comment (Workings): Open pit mine

Comment (Commodity): Ore Materials: gold

Comment (Commodity): Gangue Materials: quartz, pyrite, arsenopyrite, sericite, and small amounts of sphalerite, chalcopyrite, tetrahedrite and galena.

Comment (Deposit): The LJ Ridge deposit is located about a mile east of the Pits 1-5 deposits and about two miles northwest of the Top deposit area. Ore at LJ Ridge is hosted mainly by a north-south-trending structure 6 to 15 meters wide and to a lesser degree by favorable stratigraphic horizons in the Dunderberg Shale.

Comment (Development): Placer Dome began exploration on the Bald Mountain property in 1977. IN 1996, it was reported that the LJ Ridge deposit was the most recently discovered of the Bald Mountain district orebodies, after the No. 1-5, RBM, Rat, Top, Mahoney Canyon and Sage Flat deposits. Mining the LJ Ridge deposit was completed in 2000. In 2006, Barrick Gold Corp. acquired the LJ Ridge property through its acquisition of Placer Dome U. S., Inc.

Comment (Economic Factors): TIn 1996, the LJ Ridge orebody was reported to contain approximately 4 million tons of ore grading 0.1 opt gold.

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References

Reference (Deposit): The Geological Society of Nevada 1996 Spring Field trip, Geology and Gold Deposits of Eastern Nevada, GSN Special Publication No. 23.

Reference (Deposit): Hose, Blake, and Smith, 1976, Geology and Mineral Resources of White Pine County, Nevada, NBMG Bulletin 85.

Reference (Deposit): Hitchborn 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.

Reference (Deposit): 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.

Reference (Deposit): BLM, 2004, Bald Mountain Mine Exploration Program Programmatic Environmental Assessment NV040-04-023, Case File # N78825.

Reference (Deposit): Hill, J. M., 1916, Notes on some Mining Districts in Eastern Nevada, USGS Bull. 648, p. 152-161.

Reference (Deposit): Dean, D. A., Benedetto, K. M. F., Durgin, D. C., 1991, Part Two: Ely - Bald Mountain - Ely Road Log, in Buffa, R. and Coyner, A., eds., Geology and Ore Deposits of the Great Basin - Field Trip Guidebook Compendium, The Geological Society of Nevada, Reno, p. 136-162. 1981.

Reference (Deposit): NBMG Map M84.

Reference (Deposit): NBMG, 1994, MI-1993

Reference (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.

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Nevada Gold

Nevada has a total of 368 distinct gold districts. Of the of those, just 36 are major producers with production and/or reserves of over 1,000,000 ounces, 49 have production and/or reserves of over 100,000 ounces, with the rest having less than 100,000 ounces. Read more: Gold Districts of Nevada.