Preble Mine

Site Name

Primary: Preble Mine

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Commodity

Primary: Gold
Tertiary: Mercury
Tertiary: Antimony
Tertiary: Barium-Barite
Tertiary: Copper

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Location

State: Nevada
County: Humboldt
District: Getchell 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: Winnemucca BLM Administrative district

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Holdings

Not available

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Workings

Not available

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Ownership

Owner Name: Pinson Mining Co.
Info Year: 1987

Owner Name: Lacana Gold
Info Year: 1984

Owner Name: Cordex
Info Year: 1984

Owner Name: Pinson Mining Co.
Info Year: 2004

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Production

Not available

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Deposit

Record Type: Site
Operation Category: Past Producer
Deposit Type: replacement/fault zone; sediment-hosted disseminated gold
Operation Type: Surface-Underground
Year First Production: 1985
Year Last Production: 1990
Discovery Year: 1972
Years of Production:
Organization:
Significant: Y
Deposit Size: S

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Physiography

Not available

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Mineral Deposit Model

Model Name: Sediment-hosted Au

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Orebody

Form: tabular

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Structure

Not available

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Alterations

Alteration Type: L
Alteration Text: Rocks have been subjected to a moderate amount of silicification (jasperiod development), but not as much as at the Pinson Mine. A small sill along the footwall shear in the center of the deposit has been argillically altered.

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Rocks

Name: Volcanic Rock (Aphanitic)
Role: Associated
Description: small highly altered sill occurs along footwall of deposit
Age Type: Associated Rock
Age Young: Tertiary

Name: Shale
Role: Host
Age Type: Host Rock
Age Young: Middle Ordovician
Age Old: Late Cambrian

Name: Carbonate
Role: Host
Age Type: Host Rock
Age Young: Middle Ordovician
Age Old: Late Cambrian

Name: Phyllite
Role: Host
Description: light gray contorted
Age Type: Host Rock
Age Young: Late Cambrian
Age Old: Middle Cambrian

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Analytical Data

Not available

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Materials

Ore: Gold

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Comments

Comment (Deposit): The Preble deposit mineralization consists of disseminated gold wholly within thin-bedded, silicified carbonaceous and calcareous shales and silty limestones of the middle member of the Preble Formation. Mineralization occurs in a broad NE-trending zone of shearing, brecciation, and silicification that roughly parallels bedding, dipping 30 degrees southeast. Mineralization is evenly disseminated in the zone, with grades terminating abruptly at the hanging wall and footwall of the shear zone. Gold is strongly associated with replacement quartz. White calcite veins are common in limestone beds, and quartz veinlets and stockworks are abundant in shale and phyllite. In the pit the phyllite is light gray, but irregular iron oxide stained zones several meters wide cut the phyllite. Ore mined in the pit consists of both gossan-bearing rock and light gray contorted phyllite. A few 5 cm by 15 cm pods of milky quartz (often drusy), occur in the iron-stained zones. Traces of oxide copper minerals are reportedly present locally. Rotary drilling in the Preble ore body stopped when they entered carbonaceous, unoxidized ore at 60 m deep. This carbonaceous ore that has not been oxidized by supergene processes is reportedly not amenable to cyanidization without pre-treatment.

Comment (Commodity): Ore Materials: gold

Comment (Identification): This record is an update of earlier record #M232748 for the same deposit from which all material has been extracted and incorporated into the current record.

Comment (Location): The Preble Mine is located just on the south side of Granite Creek, on the eastern flank of Adam Peak in the Osgood Mountains.

Comment (Development): The Preble Deposit was discovered in 1972 by Whit DelaMare while prospecting for Cordex Syndicate. It is often lumped together with the Pinson Deposit 12 miles north, as the "Pinson-Preble" properties because ownership was the same. The property was evaluated and re-evaluated for several years and a 330-foot adit was driven in 1975 to procure a bulk sample of the gold ore for metallurgical testing. Higher gold prices in 1979 prompted a new feasibility study and in 1980, press releases stated that 13,400 feet of drilling in 40 holes indicated 1.2 million tons of ore averaging 0.074 ounces of gold per ton with a stripping ration of 1.5:1. The orebody was open-pit-mined with ore from higher-grade zones shipped to the Pinson Mill, and the lower grade material heap-leached near the pit site. Production of 280,000 tons of ore (13,000 ounces of gold) per year began in 1984. Cordex; Lacana Gold (26.25 % owned) (1984); Pinson Mining Co., owner, operator (1987). Owner was still listed as Pinson Mining Co in 2004, although ownership may have transferred to Homestake and then Barrick with recent acquisitions.

Comment (Economic Factors): Reserves of the Preble Deposit in 1985 were reported as 1.8 million tons of ore grading 0.062 ounces of gold per ton and in 1986 were reported as 3.16 million tons of ore grading 0.093 ounces of gold per ton heap leach ore and 80,000 tons of ore grading 0.242 ounces of gold per ton mill grade ore. In 1989, remaining reserves of 15,110 ounces of gold were reported. Production from the Preble Deposit was as follows: 1985: 17,000 ounces of gold 1987: 28,000 ounces of gold 1988: 18,828 ounces of gold 1989: included with Pinson 1990: 1,161 ounces of gold

Comment (Workings): The Preble Mine was originally developed by a series of adits, then by numerous drill roads, drill holes, several small test pits, and ultimately by an open pit.

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References

Reference (Deposit): Decker, D.J., 1974; Mineral resource ownership investigation, Nevada Garvey Ranch, Humboldt and Elko Counties,

Reference (Deposit): Nevada: Unpublished report on file at NBMG.

Reference (Deposit): Nev. Min Assn. Bull. Sept., 1979, Consortium Budgets $14 Million to Open Pinson Gold Mine.

Reference (Deposit): The Northern Miner Newspaper, Jan. 3, 1980, "Lacanex Supervising Cordex I Syndicate Feasibility Study."

Reference (Deposit): Garside, L.J., 1984, NBMG Field Examination 19 June, 1984, and sample analysis.

Reference (Deposit): Crone, W.R., 1982, M.S. Thesis, Univ. Nev. Reno.

Reference (Deposit): Crone, W.R., Larsen, T.T., Carpenter, R.H., Chao, T.T., and Sanzolone, R.F., 1984, Jour. of Geochem. Explor., vol. 20, p. 161-178.

Reference (Deposit): USGS, 1974, Map GQ-1174.

Reference (Deposit): The Mining Record, Aug. 29, 1984.

Reference (Deposit): Minesearch Annual, 1984-85, Vol VII, p. 362-367, Metals Economics Group, Boulder, Co.

Reference (Deposit): Numerous Clippings, 1982-1984.

Reference (Deposit): Geol. Soc. Nevada, 1987, Bulk Mineable Precious Metals Symposium.

Reference (Deposit): Bonham, H.F., 1986, NBMG Map 91.

Reference (Deposit): NBMG MI-1987, MI-1994-2003.

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.

Reference (Deposit): Geological Survey Open-File Report 98-206, 33 p., one 3.5 inch diskette.

Reference (Deposit): Geological Society of Nevada, 1989, Geology & Gold Deposits of the Osgood Mtns, NV: Pinson; Preble; Chimney Creek, 104 p.

Reference (Deposit): Geological Society of Nevada, 2000, Geology & Ore Deposits of the Getchell Region, Humboldt County, NV: Twin Creeks, Getchell, Pinson, & Preble Mines; FT09, 153 p.

Reference (Deposit): Oral History of John Livermore, Online Archive of California.

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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.