Bradshaw Mining District, Beaver County, Utah, USAi

Regional Level Types
Bradshaw Mining District	Mining District
Beaver County	County
Utah	State
USA	Country

The Bradshaw mining district occupies the southwestern slopes of the Mineral Mountains in southeastern Beaver County, about 15 miles west-southwest of Beaver. The district was discovered in the 1870s and was a modest intermittent Ag-Au-Pb producer for nearly a century. Total district metal production at modern metal prices is estimated at $9 million. The largest mines in the district are the Cave and Hecla mines.

The Bradshaw district lies on the Wah Wah-Tushar mineral belt in the Basin and Range Province. The Mineral Mountains expose a large (78 square mile), composite Oligocene-Miocene (25 to 17 Ma) granite, monzonite, and syenite batholith, the largest exposed batholith in Utah. The main granitic phase of the Mineral Mountains batholith has an interpreted age of about 18 to 17
Ma. The batholith has been strongly rotated to the east (40°–85°), so that the east side of the mountain is near the paleo-top of the batholith. This rotation is evident from the steep easterly dip of the Bullion Canyon Volcanics (29–22 Ma) on the east flank of the range (Rowley and others, 2005).

The Bradshaw district production has come primarily from cave-filling or replacement deposits in the Devonian and Mississippian carbonates at the Cave and Hecla mines, respectively (USGS Model 22c), just south of the southern margin of the Mineral Mountain granite batholith. Production has been approximately 11,000 tons averaging a recovered grade of about 926 ppm Ag, 9.6 ppm Au, 4.5% Pb, and minor Cu-Zn. The primary metallic minerals are pyrite, galena, chalcopyrite, sphalerite, argentite, and locally, scheelite (Earll, 1957).