Dugway Mountains Mining District, Dugway Range, Tooele County, Utah, USAi

Regional Level Types
Dugway Mountains Mining District	Mining District
Dugway Range	Mountain Range
Tooele County	County
Utah	State
USA	Country

The Dugway mining district covers the northern Dugway Range in south-central Tooele County, about 57 mi west of Eureka. The district was initially discovered in 1869, organized in 1872, and was a modest intermittent Pb-Zn producer until about 1969. Total district metal production at modern metal prices is estimated at $7.5 million. The Four Metals Pb-Zn-Ag underground mine is the leading producer.
The Dugway Range is situated on the Deep Creek–Tintic mineral belt in the Basin and Range Province in west-central Utah. Dugway is an unusual northwest-trending range, composed of gently southwesterly dipping Cambrian to Mississippian strata. The range is structurally dominated by a central northwest-trending horst encompassing the crest of the range (Staatz and Carr, 1964). Aeromagnetic surveys suggest that the embayed northwestern end of the range and possibly the central horst are underlain by intrusive igneous rocks, probably of Miocene age (~20 Ma).
Much of the Cu production in the Dugway district came from the central horst, having predominantly Cu ±Pb ±Zn ±Au veins in lower Cambrian quartzite and Zn-Pb-Ag vein and replacement deposits mainly to the northeast and east in Cambrian and Mississippian limestones and shales (USGS Model 22c). Higher Ag-Au values occur principally on the southeast end of the district. The Early Mississippian Joana Limestone, the host at the Four Metals mine, may be the most important host rock in the district. Fluorite is a common vein mineral and wulfenite is reported from several of the mines in the district (Staatz and Carr, 1964). Numerous shallow mineral exploration drill programs and a few scattered deeper holes have cut intermediate intrusives but failed to define a large intrusive body at depth under the district.
Multi-element lithogeochemistry vectors southeasterly for sedimentary rock-hosted Au-Ag signatures. The most interesting area for sedimentary rock-hosted Au-Ag is the remote Buckhorn mine area where 33 samples averaged 1.1 ppm Au and 67 ppm Ag (Au:Ag 1:60) with weak geochemically anomalous As, Pb, Sb, and Zn and strong Ba as barite (USGS Model 19c). The Buckhorn mine workings occupy an oolitic and silty carbonate horizon in the Middle Cambrian, upper Fish Springs Member of the Trippe Limestone. The 100-ft-thick favorable, slope-forming horizon is only locally silicified, but is commonly weakly Fe-stained and barite is scattered throughout the soil and subcrop (Klatt, 2006).