Fortuna Mining District, Beaver County, Utah, USAi

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

The Fortuna mining district is situated on the north end of Beaver Valley, near Gillies Hill, in Beaver County about 12 mi north of Beaver. The Fortuna district is a little recognized and minor historical Au producer, mainly active from about 1906 to 1936. Total district metal production at modern metal prices is estimated at $56,000. The Fortuna mine is the only known producer.
The Fortuna district is on the west flank of the Tushar volcanic field in the eastern Basin and Range Province of southwestern Utah. Butler and others (1920) first mentioned the district and described the mineralization as having northwest-trending, banded quartz-carbonate ±adularia veins cutting easterly dipping, propylitized Oligocene Bullion Canyon Volcanics rhyodacite porphyry host rocks. The rhyodacite porphyry wallrocks are silicified immediately adjacent to the veins (USGS Model 25c). Native gold reportedly occurs with limonite after pyrite in the veins (Butler and others, 1920) and grades of over 10 ppm Au are reported. In addition to Au and Ag, the veins are also anomalous in As, Sb, and Hg.
The mine workings consist of scattered shafts and a very small open cut (1000 tons?) at the Fortuna mine. The rhyodacite porphyry host rocks are also cut by a series of Miocene-age felsite porphyry dikes (9.1 Ma) and may be related to the Rhyolite of Gillies Hill, some of which are high-silica rhyolites (Evans and Steven, 1982). The district has undergone sporadic exploration and drill testing, including numerous drill holes by Cordex Exploration south and southwest of the Fortuna main shaft area in the early 1990s and exploration holes well north of the main shaft by Kinross Gold in the 2010s.