Northwestern Black Hills Uranium District

Region West, Northwest; Rocky Mountains
Mineral systems
Deposit types
Critical minerals
Other minerals

Information leading to the delineation of this focus area

Basis for focus area The focus area includes uranium occurrences hosted in the Barlow Canyon, Elkhorn Creek, Hulett Creek, Aladdin, Carlile, and Lance districts in Wyoming (Elevatorski, 1976; Peninsula Energy Ltd., 2020). Uranium roll-front deposits are hosted in the Inyan Kara Group: fluvial sandstone and conglomerate in the Lakota Formation and marginal marine sandstone and siltstone in the overlying Fall River Formation (Chenoweth, 1988); and the sandstones of the Fox Hills and Lance Formations (McDowell and others, 2017). The geometry of the deposits is both tabular and roll-front (Dahlkamp, 2010). The polygon is drawn to encompass five separate districts.
Identified resources Identified resources and historical production of uranium and vanadium.
Production Mines from about 29 properties in the northern Black Hills produced about 716,000 tons of ore averaging 0.22% U3O8 containing about 3.1 million lbs U3O8 from 1953 to 1968 (Chenoweth, 1988). These ores also contained about 4.4 million lbs V2O5 (Chenoweth, 1988). The Lance project has an estimated resource of 53.6 million lbs U3O8 (Peninsula Energy Ltd., 2020).
Status Current mines (Strata Energy) on standby for Lance project. Mining from the Inyan Kara Group ceased in the 1960s.
Estimated resources The Hauber mine provided about 83% of the U produced from this region (Chenoweth, 1988), with estimated reserves of 600,000 tons averaging 0.23% U3O8 (Elevatorski, 1976). The Lance deposits (Barber, Kendrick, Ross) have in place JORC compliant resources of about 53 million lbs U3O8 in the Measured, Indicated and Inferred categories (Peninsula Energy Ltd., 2020).
Geologic maps Horton and others (2017), scale 1:500,000; Hallberg, Case and Kirkaldie (2001), scale 1:100,000; Robinson and others (1964) scale 1:96,000; Sutherland (2007a, b), scale 1:100,000; various 1:24,000-scale maps.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Cretaceous Inyan Kara Group (Lakota and Fall River Formations), upper Fox Hills Formation and lower Lance Formation.
Deposits In situ resources remain at the Ross, Kendrick, and Barber deposits (Lance project). The Hauber mine (MRDS dep_id: 10091627) was the largest of about 29 producing mines in the Inyan Kara Group.
Evidence from mineral occurrences MRDS; International Atomic Energy Agency (2020b); U.S. Environmental Protection Agency (2006).
Geochemical evidence Vanadium as paramontroeseite and häggite (V/U is 1.5:1.0 for black U minerals, 0.4:1.0 for yellow oxidized minerals) (Elevatorski, 1976). Uranium ores of carnotite, tyuyamunite, uraninite in Inyan Kara Group (Elevatorski, 1976).
Geophysical evidence No data.
Evidence from other sources No data.
Comments Several small mines in historical district (mostly mined out). Most (all?) of the U production in the northern Black Hills was likely from Wyoming. There is little potential for production in the northern Black Hills of South Dakota.
Cover thickness and description Thickness variable; mostly Mesozoic sedimentary rocks.
Authors Susan Hall, Robert W. Gregory, Ranie M. Lynds.
New data needs Geophysics.
Geologic mapping and modeling needs None requested at this time.
Geophysical survey and modeling needs Electromagnetics and radiometric data may be very helpful.
Digital elevation data needs Lidar complete.