Blue Bells Mining District, Tooele County, Utah, USAi

Regional Level Types
Blue Bells Mining District	Mining District
Tooele County	County
Utah	State
USA	Country

The Blue Bell mining district is in extreme southeastern Tooele County, about 15 mi west of Eureka. The initial discoveries in the district were made in the 1890s and the district became a small intermittent Pb-Ag producer operating until 1922. Total district metal production at modern metal prices is estimated at $367,000. The most productive mines in the district were the Black Hawk and Morgan.
The Blue Bell district covers a portion of the east flank of the Sheeprock Mountains and adjoining portions of the West Tintic Mountains of the Basin and Range Province. The Sheeprock Mountains are composed of a thick sequence of northeast-dipping Neoproterozoic Sheeprock Group quartzite, metaconglomerate, and slate (Cohenour, 1959). To the west, these rocks have been intruded by the Miocene (20.9 Ma) Sheeprock granite. The intrusion is an aluminous, anorogenic (A-type), high-silica granite (Christiansen and others, 1988). The Sheeprock Mountains have been rotated eastward by post-intrusive listric extensional faulting so that a deeper level of the Blue Bell paleo-hydrothermal system is exposed on the west and shallower levels are exposed on the east. The Blue Bell district is located 6 mi due east of the granite.
The Blue Bell district has produced about 250 tons of Pb-Ag ore (USGS Model 22c) from veins hosted in the Sheeprock Group quartzite and tillite. The primary ore minerals are argentiferous galena, sphalerite, pyrite, barite, and bismuthinite. In addition to Pb-Ag, the ores may be anomalous in As, Ba, Bi, Mo, and Sb.
In the 1980s and 1990s, jasperoids in windows of Mississippian carbonates along Vernon Creek on the east side of the district were prospected for distal disseminated Ag-Au (USGS Model 19c), particularly from Sabie Mountain to J Hill, without success. These occurrences are associated with silicification principally in the Mississippian Great Blue Limestone and may have orpiment, realgar, and cinnabar. In addition to strong As, Hg, and Sb, these jasperoids may have weak Au and Ag.