Gas Hills

Region West, Rocky Mountains
Mineral systems
Deposit types
Other minerals

Information leading to the delineation of this focus area

Basis for focus area The Gas Hills focus area in the Wind River Basin includes known deposits in the Gas Hills district, and the trace of prospective roll fronts (Boberg, 2010; Gregory and others, 2010). Mineralization is along roll fronts adjacent to conglomerate and sand channels in the Puddle Springs Member of the Eocene Wind River Formation (Dahlkamp, 2010).
Identified resources Identified resources and historical production of uranium.
Production The total resource for the basin including in situ and mined U is estimated to be at least 142 million lbs U3O8 of which open pit and underground mining from 1954 to 1988 mined about 64 million lbs (Dahlkamp, 2010). The largest producer, the Lucky Mc group, mined about 25 million lbs U3O8 from 1954 to 1988 (Pool, 2017).
Status Past mining; recent exploration, in situ resources.
Estimated resources The Peach deposit (Cameco) has estimated in-place resource of about 13 million lbs U3O8 (Cameco, 2021). Azarga Uranium identified about 7.2 million lbs U3O8 Indicated and Inferred NI 43-101 compliant resources in the Gas Hills (primary targets Day Loma, Loco-Lee, George-Ver and Bullrush) (Beahm, 2017).
Geologic maps Gregory and others (2010), scale 1:500,000; Sutherland and Hausel (2003), scale 1:100,000; Gregory and Broes (2018), scale 1:24,000; Minard (1980), scale 1:24,000; Toner and others (2016), scale 1:24,000; Lynds and others (2016), scale 1:24,000; Soister (1966a, b, 1967a, b), scale 1:24,000; Cola and Sutherland (2014), scale 1:24,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage. No known electromagnetic coverage.
Favorable rocks and structures Eocene Wind River Formation (Puddle Springs Member).
Deposits The largest producers were numerous mines along the central ore trend, including the Lucky Mc mine (MRDS dep_id: 10072335). In addition the central trend, the western and eastern ore trends also produced many millions lbs of U3O8.
Evidence from mineral occurrences MRDS; International Atomic Energy Agency (2020b); U.S. Environmental Protection Agency (2006).
Geochemical evidence No data.
Geophysical evidence No data.
Evidence from other sources No data.
Comments Future ISR (in situ recovery) mining operations are on hold.
Cover thickness and description Most future mines will be surface pit operations at less than 150 m; south of Beaver Rim, deposits lie at depths of up to 350-400 m.
Authors Susan Hall, Robert W. Gregory.
New data needs Geophysics.
Geologic mapping and modeling needs Mapping recently completed.
Geophysical survey and modeling needs High resolution Rank 1 aeromagnetic and aeroradiometric surveys needed, especially over areas south of Beaver Rim.
Digital elevation data needs Lidar complete in Wyoming.