Friedman, Constantine, NBMG Sample Site 2657, Humbolt-Springer, Sutton Ii Mine, Uncle Sam, Nevada-Massachusetts, Mill City, Springer Shaft, Stank Mine, Humbolt Mine, Summit Mine, Tungsten

A tungsten mine located near Winnemucca. Inactive in 1984. Owned by Utah International (20%) & General Electric (80%).
Deposit: G-awm - width dimension is downdip dimension and represents a minimum downdip width that is known to continue downdip. F-atm - thickness includes two replaced carbonate beds 7.6m apart, one 3.0m thick and the other 0.9m thick. The two beds are separated by rock having no tungsten metal content.

Structure: The Stank fault strikes N-S for 1.5 miles. Strata strike N20E. The strata on the west side of the fault dip east, while on the east side of the fault, beds dip 70 west. Post-mineral faults also present, in many cases off-setting mineralized skarn beds. Basin and Range faulting

Alteration: silicification, albitization

Commodity: Ore Materials: scheelite, powellite Gangue Materials: epidote, garnet, quartz, pyrite, wollastonite, tremolite, calcite, diopside, garnet, quartz

Deposit: The scheelite deposits of the district occur in roughly parallel limestone beds that have been altered to skarn. The main production has been from a few distinct beds that traverse the district with a general northerly trend. The main production zone is about a mile long and about 0.75 mile wide bounded on the north by the Olsen stock. The southern boundary is more gradational, governed by proximity to the Springer Stock. Virtually all district tungsten production has come from mines on five ore beds: the Humboldt, Springer, and Stank ore horizons, and the Sutton No. 1 and Sutton No. 2 mines on the Sutton horizon. The Summit-O'Byrne bed strikes NE, dips steeply SE and extends from the south rim of the George Mine pit across Stank Hill and into Stank Canyon, where it comes in contact with the small southwest stock. Ore in the tactite body was limited to a triangular segment of the bed lying between the surface and the plane of the Stank fault. Ore on the south was limited by the gradational limestone-tactite boundary. Scheelite occurs as disseminations and fracture coatings in skarn bodies and as irregular blebs and crystal masses in quartz veins that cut through the skarn and granodiorite. Scheelite is the main ore mineral, accompanied in places by small amounts of molybdenite, chalcopyrite, rare bismuthinite, and up to several percent pyrite. Powellite occurs only as a secondary mineral associated with molybdenite.

Deposit type: W skarn

Development: Although the Eugene Mountains were mined for silver and gold beginning in 1862, tungsten was not discovered there until Emil Stank had a sample analyzed that he had collected while silver prospecting a few years earlier. The onset of World War I had increased demand for tungsten, and Stank?s discovery was rapidly brought into production by three companies within months of the claim locations. Pacific Tungsten Company took over Stank?s claims, Thomas Sutton formed the Mill City Tungsten Mining Company to work his claims east of , and L. T. Friedman formed the Nevada-Humboldt Mining Company to mine the deposits on Humboldt Hill. Two of the companies were operating mills by the end of 1918, but the end of the war brought the cessation of tungsten mining at Mill City in 1919. By 1925, the Nevada-Massachusetts Company under Charles Segerstromhad purchased and consolidated all of the main district properties and was the sole operator at the Tungsten camp until 1958 when production ceased. The property was maintained on standby until 1962,after which it slipped into disrepair. In 1969, however, Segerstrom?s heirs, operating under Tungsten Properties Limited partnership, again acquired the property and in 1971 negotiated a deal with General Electric Co. to re-evaluate the property. After extensive explorration and development, GE constructed a $55 million mine, mill, and processing plant, which operated for less than a year in 1982, at which time depressed prices forced closure again. For more than 20 years, the mine has been kept in ?mothballs? with a caretaker to maintain equipment in working condition. A buyer was being sought (2005) to reopen the mine since it is in a ?turnkey? state ready to be brought back into production will minimal renovation.

Geology: The Stank orebody appears to be a pendant-like mass. Triassic sediments are intruded by granodiorite stocks and dikes, producing contact metamorphism (garnet-epidote-wollastonite-tremolite). These were followed by andesite dikes.

Ore(s): Ore formation was controlled primarily by proximity of limestone beds to igneous intrusive bodies, and secondarily by faulting.

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Mineral List

16 valid minerals.

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