Gold Springs Mining District (Hamlin Valley), Iron County, Utah, USAi

Regional Level Types
Gold Springs Mining District (Hamlin Valley)	Mining District
Iron County	County
Utah	State
USA	Country

The Gold Springs mining district (Pike’s Diggings) lies along the Nevada border about 55 mi west-northwest of Cedar City in northwestern Iron County. The district is a modest Au producer totaling about 9300 ounces, some of which came from Nevada, between 1897 and 1948 (Perry, 1976). Total district metal production at modern metal prices is estimated at $11 million. The largest producers in the district are the Jennie and the Jumbo underground mines.
The Gold Springs district is situated in the Paradise Mountains of the Basin and Range Province. Gold-silver production was derived from a series of generally northerly trending, moderately east-dipping, epithermal, low-sulfidation, banded or crustiform, quartz-carbonate-adularia ±pyrite veins cutting Miocene-age volcanic rocks (USGS Model 25c). From oldest to youngest, the volcanic sequence consists of andesitic flows, ash-flow tuffs, and rhyolitic flows. These volcanic rocks are cut by coeval porphyritic rhyolite intrusives (16.5 Ma) associated with the Gold Springs depression (cauldron). The porphyritic rhyolite plug, which lies in the depression just across the state line in Nevada, is phyllically to argillically altered (Williams and others, 1997). Veins near the Gold Springs depression are higher in Au and the more distal veins carry higher Ag. Ferrimolybdite is reported from the Jumbo lode in Utah. Geochemical sampling of the Au-Ag veins indicates elevated Mo, F, Pb, Cu, Mn, Te, Hg, and U. A shaft near the center of the porphyritic rhyolite (on Bull Hill, NV) is developed on a Au-Ag-rich, fluorite-hematite- clay pipe (Perry, 1976). The Charley Ross mine (Nevada), immediately south of the Gold Springs depression, intersected a body of “talc” 40 ft wide containing locally high Au-Ag values, apparently as sylvanite.
The Gold Springs district is being actively explored for exploitable Au-Ag mineralization. This work has defined a measured and indicated resource on the Jumbo Au-Ag stockwork of 13,591,000 tons of 0.53 ppm Au and 13.6 ppm Ag at a 0.3 ppm Au cutoff. The preliminary economic assessment calls for a 15,000 ton per day, open-pit, heap leach operation with a 2:1 stripping ratio (Lane and others, 2015).