Pinson Mine, Potosi Mining District, Osgood Mountains, Humboldt County, Nevada, USAi

Regional Level Types
Pinson Mine	Mine
Potosi Mining District	Mining District
Osgood Mountains	Mountain Range
Humboldt County	County
Nevada	State
USA	Country

Commodity: Ore Materials: gold Gangue Materials: quartz, chiastolite/andalusite, cordierite, fluorite, barite kaolinite.

Deposit: A 1984 report describes the deposit: the Pinson "A" zone is 1000 feet long by 60 feet thick containing 1,500,000 tons of ore averaging 0.18 ounces per ton gold, covered by 10-50 feet of alluvium. Further drilling indicated 1,700,000 tons averaging 0.15 ounces per ton gold, plus an additional tonnage of low-grade ore in the B zone in the vicinity of the old pit. A major NE-striking fault zone 50-70 feet wide, dipping 40-50 SE controls gold mineralization. It has been traced by drilling for 8,000 feet. The "A" orebody is localized by this shear zone where it coincides with the contact between the Preble and Comus Formations. It consists of fine disseminations in jasperoid. There are irregular zones of low-grade gold ore along bedding planes and minor fractures in argillite in the footwall of the ore-controlling fault. A conspicuous contact metamorphic aureole surrounds the granodiorite stock, extending irregularly up to 10,000 feet out from the margins of the intrusive. A number of tungsten-bearing tactite deposits rim the granodiorite, forming wherever a calcareous bed was present within the contact zone. The Pinson Mine also lies within this contact aureole, with granodiorite outcropping 1200 feet north of the mine. At Pinson gold occurs in fractures that cut calc-silicate rocks of the Comus Formation.

Deposit type: Sediment-hosted Au

Development: The original claims were staked by Clovis Pinson in 1945, and were held in the family through 1979. It was mined in 1949 by open pit methods. The new Pinson Deposit was discovered on leased claims in 1971 by John Livermore and Pete Galli of Cordex. The Pinson Mine was put in production in 1980 as an open pit mine and conventional gold mill processing approximately 300,000 tons ore per year. 1979 known reserves of medium grade ore were sufficent for five years' operations, with additional reserves of low-grade to extend mine life to 10 yr or more. In 1980 a heap leach operation was commenced to recover gold from 3,000, 000 tons of lower-grade ore. The mine was active in 1980, employing about 80 persons. The new Pinson Deposit was discovered in 1971 by John Livermore and Pete Galli. Known reserves in 1979 were 1.5 million tons plus more low grade ore. It was owned and operated in 1981 by Cordilleran Exploration (Cordex). It was listed as an active open pit mine and mill with cyanidation operation in 1983, employing a total of 130 persons. The property position was later consolidated with the Preble Mine to the south. The Preble-Pinson property is made up of 17 complete and 8 partial sections (approximately 20 square miles or 5,300 hectares) of the railroad checkerboard, covering much of the projected intersection zone where the Battle Mountain Gold Belt crosses the Getchell Gold Belt in portions of the Edna Mountain and Osgood Mountains areas. Portions of the property occur about 1 mile south of the Pinson Mine and about 1.3 miles NNE of the Preble mine. These two mines occur along the NNE trend of the Getchell Gold Belt. The southeast corner of the property is approximately 6 miles NW of the Lone Tree Mine, which occurs within the Battle Mountain Gold Belt. Preliminary work indicates that the main intersection zone is buried under basalt. Therefore some initial work closer to existing or abandoned mines will be undertaken such that the structural geometries within the Battle Mountain Gold Belt will provide convergence zones extrapolated below the basalts for future drilling. Early in 1997, Homestake Mining Co. and Barrick Gold Corp. purchased the interests in the Pinson property not already owned by them, to increase their ownership of the property to 50% each, with Homestake as the manager. Deep exploration potential was the reason for the purchase. By the end of the year, Barrick Gold Corp. announced that production was expected to wind down at Pinson by mid-year 1999 unless current exploration on the property succeeds in identifying new reserves. Reported 1997 production from the Pinson Mine was 51,600 oz of gold (DMR, 2/26/97; Homestake Mining Co. press release, 2/19/98; Humboldt Sun, 9/15/97; In 1999, At Homestake Mining Co.?s Pinson Mine, which was closed in January 1999, work is ongoing to recontour, cover, and revegetate the waste rock piles and tailings facility, and to neutralize the leach pads. Residual heap leach production continued throughout most of 1999. An exploration program with joint venture partner Barrick Gold Corp. will continue. The partners expect to spend approximately $3 million exploring for deep orebodies on the lands controlled by the Pinson joint venture (Yahoo Mining/Metals News, 1/29/99, 7/27/1999). Also in the Potosi district, Western Exploration recorded the BU Claims in T38N, R42E, (BLM mining claim records, 4/19/1999). In 2000, Homestake Mining was planning to test potential deep high-grade targets at the Pinson property while concurrent reclamation was ongoing. In 2003, Victoria Resource Corp. acquired the Preble-Pinson property as a lease of all of Newmont?s mineral interests in parts or all of approximately 24 square miles of the checkerboard property in the Edna and Osgood mountains. In 2005, Atna Resources began exploring the underground potential of a high-grade ore zone with a drift in the bottom of the Pinson open pit. In 2006, Atna Resources Ltd.(70%) announced that recent underground drill results at the Pinson/Ogee Zone Project include 10.5-15.8 feet @ 0.616 opt Au (UGOG-006); 47.5- 51.5 feet @ 0.260 opt Au (UGOG-008); 55.5-62 feet @ 0.115 opt Au (UGOG-013); 86.8-107.5 feet @ 0.454 opt Au (UGOG-013); 213-227 feet @ 0.549 opt Au (UGOG-013); 247.5-263.5 feet @ 0.289 opt Au (UGOG-014) and 74- 135.5 feet @ 0.505 opt Au (UGOG-015).

Ore(s): The ore-controlling fault zone at Pinson maybe a southern extension of the Getchell Fault.

Other Databases

Wikidata ID:	Q49440612
GeoNames ID:	5707354
Link to USGS MRDS:	10310313
Link to USGS MRDS:	10149740

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