Winrock Mine

The Winrock Mine is a gold mine located in White Pine county, Nevada at an elevation of 6,972 feet.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: Winrock Mine
Secondary: Blowout Pit
Secondary: Deer Camp pit

Commodity

Primary: Gold

Location

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

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

Holdings

Not available

Workings

Not available

Ownership

Owner Name: USMX, Inc. (51%)/Pegasus Gold Inc. (49%)

Owner Name: USMX, Inc.

Owner Name: Placer Dome U. S., Inc.
Info Year: 2004

Production

Year: 1991
Mined: 399000.000 mt
Material type: ore
Description: Ap_Grade: ^0.037 Opt Au

Deposit

Record Type: Site
Operation Category: Producer
Deposit Type: sediment-hosted gold
Operation Type: Surface
Year First Production: 1991
Year Last Production: 1992
Years of Production:
Organization:
Significant: Y
Deposit Size: S

Physiography

Not available

Mineral Deposit Model

Model Name: Sediment-hosted Au

Orebody

Not available

Structure

Type: R
Description: The Maverick Springs Range is an east-tilted fault block

Type: L
Description: At Winrock, the dominant structure controls are N25W and N20- 40E.

Alterations

Not available

Rocks

Name: Shale
Role: Host
Age Type: Host Rock
Age Young: Late Mississippian
Age Old: Early Mississippian

Name: Limestone
Role: Host
Age Type: Host Rock
Age Young: Early Mississippian

Name: Sedimentary Rock
Role: Host
Age Type: Host Rock
Age Young: Late Devonian
Age Old: Early Mississippian

Analytical Data

Not available

Materials

Ore: Gold
Gangue: Quartz

Comments

Comment (Economic Factors): In 1990, the Winrock deposit reserves were reported at 993 Kilotonnes of ore grading 0.037 opt gold. The Casino-Winrock mines produced an aggregate 20,000 ounces of gold in 1991 and produced an aggregate 19,800 ounces of gold in 1992, for a total production of 39800 ounces for the two deposits. The Casino-Winrock heap leach pad contained 1.43 million tons of ore. Rinsing of the heap leach began in 1994 and was essentially complete by 1997.

Comment (Identification): This record includes all material from earlier record #RE00278 which should be deleted from the database. The deposit is often combined with the Casino deposit in the literature. The Hilltop pit is sometimes included with the Winrock Mine but here is included with the Yankee Mine. The Winrock Mine is part of Placer Dome?s Bald Mountain Mine project.

Comment (Deposit): The Winrock Gold deposits occur in a structurally complex zone between two major NW-trending fault zones that both have both dip-slip and left-lateral strike slip components. The intervening rocks have been uplifted, rotated and inensely fractured by faults trending NE and NW. The structures have created permeability in the rocks allowing migratoin of upward-moving hydrothermal fluids.

Comment (Development): The original claims in the mine area were staked n 1978 by a grubstaked geologist working for Amselco Minerals. USMX INc. leased the property in 1987 and began a soil geochemical survey that delineated a gold anomaly that was drilled in late 1987. By 1989, USMX drilling had delineated a mineral resource of 2.9 million tons of oxide gold ore grading 0.038 ounces per ton. In 1991 the mine began operations under a 51/49 USMX-Pegasus Joint Venture. Mining commenced in July, 1991 and was completed in 1992. Haul distance was 1.3 miles and strip ratio was 0.93:1.

Comment (Commodity): Ore Materials: gold

Comment (Commodity): Gangue Materials: iron oxides, quartz

Comment (Location): The mine is located about 1500 meters east-southeast of Julian Well.UTM is for the Blowout pit; Deer Camp pit is about 250 meters away.

Comment (Workings): A single heap leach pad was developed to treat ore from both the Casino and Winrock deposits and production is lumped together for the two open-pit mines.

References

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.

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

Reference (Deposit): Cox, John, and Lamborn, John, 1991, Geology and mineralization of the Winrock Project, White Pine County Nevada; in Geology and ore deposits of the Great Basin; field trip guidebook compendium, eds. Buffa, Ruth H; Coyner, Alan R.

Reference (Deposit): USMX, 1990, Annual report for 1989.

Reference (Deposit): USMX, 1992, Annual report for 1991

Reference (Deposit): NBMG MI-88 through MI-02

Reference (Deposit): NBMG Map 91, 2nd, 3rd

Reference (Deposit): DEIS, 1995

Reference (Deposit): FEIS, 1995

Reference (Deposit): Amer. Mines (1991-92), 1991 thru Amer. Mines (2000), 2001

Reference (Deposit): Nevada Land Status, 1990

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.