Lucin Mining District, USAi

Regional Level Types
Lucin Mining District	Mining District
USA	Country

The Lucin (Buell) mining district lies in the northern Pilot Mountains in southwestern Box Elder County, Utah (major part) and Elko County, Nevada (minor part). Mineralization was initially discovered in the district in 1868. Lucin production was fairly continuous from the completion of the transcontinental railroad (1869) until the 1920s, and then intermittent until 1963. Lucin is the oldest and second most productive district in Box Elder County and the county’s largest producer of Cu, Pb, and Fe. Lucin’s total production is about 171,000 tons of predominantly Cu, Pb, and/or Ag ore with subordinate Fe, Zn, Au, and possibly Mo (Doelling, 2006). Total district metal production at modern metal prices is estimated at $58 million. The Copper Mountain Group and Tecoma mine are the district’s largest producers.
The Pilot Mountains are a prominent range in the northeastern Basin and Range Province. The geologically complex Lucin district is underlain by a large slide block of generally north-striking, moderately east-dipping Paleozoic sedimentary rocks sitting on the west-dipping faulted top of the Eocene (39 Ma) McGinty monzogranite (about 27 sq mi). The top of the monzogranite reaches its highest elevation under the Copper Mountain–Tecoma Hill corridor. The rocks of the district have been cut by numerous low-angle, generally bedding-parallel, detachment and attenuation faults and generally younger east- and north-striking, high-angle faults. Some of the low-angle normal faults have resulted in considerable brecciation, particularly at the top of the cliff-forming Devonian Guilmette Formation. There are also at least two periods of dikes, an early (Eocene?) set which primarily cut the monzogranite stock and a later Miocene diabase set which cut stock, Paleozoic strata, and Tertiary sedimentary rocks (Miller and Schneyer, 1985).
The majority of the Lucin district’s production was from the Copper Mountain and Tecoma Hill mines in the Regulator Canyon area near the center of the district. The mineralization in the Lucin district is zoned from a central Cu-Fe sector near Copper Mountain to Pb-Zn-Ag-Au ±Cu ±Mo mineralization along the slopes near Tecoma Hill (USGS Model 19a). The ores are mostly oxidized with remnant grains of galena, sphalerite, chalcopyrite, and pyrite, along with minor bismutite and wulfenite. Farther outward from these mineral zones, the district hosts extensive jasperoid breccias and some subeconomic distal-disseminated Au-Ag shows (USGS model 19c).