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

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

Sec 29 T38N R42E. Tactite.
Structure: N-S Trending Fault Faulting

Deposit: The limestone-granodiorite contact crosses the pacific property in an irregular n-s line with the granodiorite dipping beneath the limestone at an angle of about 60e. Tactite crops out along the hill surface in lenticular,tabular bodies, separated by areas in which exposures are poor and tactite probably thin or absent. The tactite is widest and highest grade in steeplyplunging trough-like structures formed at reentrants in the contact. Only a small fraction of the tactite contains more than 0.5 % w03 and much of it contains less than 0.2 %. A curved band of tactite about 375 ft from the north edge of the property, included a layer of garnet-rich material from 3-to 5 ft thick that averaged about 1.0 % w03 for a length of 10-0 ft. An adit called the pacific tunnel, driven west from the base of the hill passes through about 600 ft of crushed rock in the getchell fault zone before entering solid limestone. After passing through an additional 100 ft of limestone, the adit cuts the granodiorite contact at about 450 ft below the outcrop. Tactite about 2 ft thick and containing sparse scheelite was intersected at the contact. Drifting along the contact to the north of the adit intersected scheelite-bearing ore of minable grade and thickness that was mined by shrinkage stopes up to the bottom of the open pit. Both open-pit and underground mine, although pit accounted for largest part of the production. Tactite body was mined down dip approx 550 ft in underground workings and open pit. The property is estimated to have remaining reserves of about 64,000 tons or at 0.33% wo3 ; info.src : 1 pub lit; 2 unpub rept; 3 field observ

Deposit type: W skarn

Development: Mined principally by open pit between 1951 and 1956 by getchell mines, inc., yielding a total of 279,700 tons ore -that was trucked to the getchell mill. Underground mining by crosscut adits and shrinkage stopes yielded additional ore during the same period, but the tonnage and grade was not reported- separately from other company mines in the district. Estimated remaining reserves of 64000 tons of 0.33 % w03 ore

Geology: Contact trends n, dips 55 to 60 e. Tactite body is tabular, thickest near a S-plunging trough formed by granodiorite projection.

Rock formation(s): Osgood Mtns. Stock
Preble Formation;Preble Formation


Ore(s): Tactite At Limestone/Granodiorite Contact

Other Databases

Link to USGS MRDS:	10045087

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References