Crescent Mine, Evolution Mining District, Shoshone County, Idaho, USAi

Regional Level Types
Crescent Mine	Mine
Evolution Mining District	Mining District
Shoshone County	County
Idaho	State
USA	Country

Located approximately 2.0 miles (3.2 kilometers) up Big Creek from its confluence with the South Fork of the Coeur d' Alene River (3.2 miles (5.2 kilometers ) east of Kellogg, Idaho.
Structure: Osburn Fault Alhambra Fault is a 15 to 18 meter wide fracture zone with 0.3 to 1.2 meters of fault gouge in the footwall. The fault is steeply reverse and right lateral, strikes N50-80W, dips 55 to 65SW with St. Regis-Revett Formation quartzite in the hanging wall and Wallace Formation quartzite in the footwall. Big Creek Anticline (WNW) - deposit within the overturned north limb. Big Creek Fault Silver Syndicate Fault.
Alteration: A rich oxide zone in the upper part of the vein, 137 meters long and 0.9 meters wide, was mined to 91 meters depth Veins are surrounded by halos of disseminated minerals in the wall-rock, from the vein outward, these are zones of disseminated arsenopyrite, sericite, pyrite, and carbonate. The carbonate halo begins at 24 meters and extends out to 46 to 61 meters. Tectonics: Belt Basin
Commodity: Pitchblende or uraninite was found in small concentrations in two places within the hanging-wall of the Alhambra fault in St. Regis Formation quartzite filling fractures that cut iron oxide zones 0.3 to 0.6 meters thick. The fracture filling consists of the uranium mineral, sericite, pyrite, chalcopyrite, tetrahedrite, calcite, and quartz.
Deposit type: Polymetallic veins
Rock formation(s): Wallace Formation; St. Regis Formation; Revett Formation
Ore(s): All ore within or in structures associated with the Alhambra Fault. All commercial ore-bodies hosted by quartzite, mostly within the St. Regis-Revett transition zone.

Other Databases

Link to USGS MRDS:	10192855

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References