South Uinta Mining District, Wasatch County, Utah, USAi

Regional Level Types
South Uinta Mining District	Mining District
Wasatch County	County
Utah	State
USA	Country

The South Uinta mining district stretches for over 70 mi along the south flank of the Uinta Mountains through portions of Wasatch, Duchesne, and Uintah Counties. The South Uinta district was a minor Fe producer, shipping about 500 tons of ore in 1879–80 to Park City smelters to be used as flux (Bullock, 1970). Total district metal production at modern metal prices is estimated at $30,000. Most of the district’s production came from the Ferry Iron mine in Wasatch County with inconsequential production from the Paint mine in Duchesne County.
The South Uinta district encompasses a series of small Fe and some Mn occurrences along the South Flank fault zone in the Middle Rocky Mountain province. The N. 80 E.-trending, steeply south-dipping fault zone imperfectly marks the boundary between the Proterozoic quartzite of the high Uinta Mountains and the Paleozoic sedimentary strata to the south. The South Flank fault zone has a long, complex history involving both reverse and normal movements. Mineralization in the district is likely related to the expulsion of overpressured, reducing hydrothermal brines from the Uinta Basin to the south (Conn, 2005; Nelson and others, 2005).
The Ferry (Rhodes Plateau) Fe mine lies on the west end of the South Flank fault zone, just east of Soapstone Basin. Mineralization occurs along a wide brecciated fault zone cutting Lower Mississippian Madison Limestone. The ore is gray, fine-grained, massive specularite and red hematitic ocher that occurs as a 15-ft-thick lens of breccia filling. Six ore samples from the mine averaged 57.2% Fe and 20.1% SiO2 (Bullock, 1970). The Paint Fe mine lies on a splay of the South Flank fault zone west of Moon Lake. The ore occurs as small pods of reddish, ocherous hematitic breccia hosted in Madison Limestone that has been used as pigment (Bullock, 1970). The Fe ores of the South Flank fault zone may show some Cu carbonates and can be anomalous in Ag, As, Co, Cu, Mo, Mn, Pb, V, and Zn (Conn, 2005). Several other generally similar, but smaller Fe prospects occur along the length of the South Flank fault zone. The district also includes some scattered, small, poorly described Au-Ag prospects (Conn, 2005). In addition, a few small emeralds have been found near the fault zone along the South Fork of Rock Creek, hosted by sulfidic Red Pine Shale (Nelson and others, 2005).