Washington Mining District, Needle Range, Beaver County, Utah, USAi

Regional Level Types
Washington Mining District	Mining District
Needle Range	Mountain Range
Beaver County	County
Utah	State
USA	Country

The Washington district lies about 50 mi northwest of Cedar City in the Indian Peak Range in southwestern Beaver County and adjoining portions of Iron County. The district is located south of the smaller Indian Peak Cu-Au-Ag district. The Washington district has been a modest fluorite producer having minor Pb-Zn and subordinate Ag-Cu-Au production (Perry and McCarthy, 1977). The district is the second largest fluorite producer in the state. Total district metal production at modern metal prices is estimated at $4 million. The Cougar Spar fluorite mine and the New Arrowhead Pb-Zn mine are the most important producers in the district.
The Washington district lies on the Blue Ribbon lineament in the Basin and Range Province. The bulk of the mineralization in the Washington district was derived from fissured and replaced Paleozoic sedimentary rocks; however, Tertiary volcanic rocks associated with the Indian Peak caldera are ore hosts locally. The Indian Peak Range was rotated eastward during Miocene extension so that the Oligocene units dip moderately eastward, but mid-Miocene volcanic units dip gently. The Oligocene Wah Wah Springs Formation dacitic ash-flow tuffs are intruded by a large plug of essentially coeval granodiorite porphyry. These units are cut by a series of narrow (about 15-ft-thick), N. 65° E.-trending, steeply north-dipping Miocene rhyolite porphyry dikes. The rhyolite dikes contain accessory fluorite, secondary biotite, and fine-grained disseminated pyrite (Best and others, 1987). The Cougar Spar fluorite mine in southwestern Beaver County has been a modest producer, with about 20,000 tons of fluorite produced, but also had some minor Pb and Zn production. The mine began as an underground operation but was later operated as an open pit. The Cougar Spar fluorite vein is along a N. 15° W. fault zone that dips steeply to the east. The fault juxtaposes granodiorite on the west and dacitic tuffs on the east. The quartz-fluorite-calcite veins and breccias are less than 5 ft wide, traceable for about 200 ft on the surface, and the average grade is about 40% fluorite. About nine other small mines and prospects with fluorite are in the district (Bullock, 1976). The New Arrowhead mine had limited production, about 2200 tons, of Pb-Zn ±Cu ±Ag ±Au ore, primarily in the 1940s. The ore is hosted in the Lower Ordovician Crystal Peak Dolomite and is estimated to average about 13% Zn, 8% Pb, 0.2% Cu, 20 ppm Ag, and 0.2 ppm Au. Galena and sphalerite are the only recognized ore minerals (Perry and McCarthy, 1977). The district has about three other Pb-Zn prospects.