Black Butte (Sheep Creek)

Region West, Northwest
States
Mineral systems
Deposit types
Commodities
Critical minerals
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Black Butte (Sheep Creek) mining district from USMIN Smith River District location polygon (MT00029).
Identified resources Identified resources for cobalt, copper, gold, and silver.
Production None (2022 startup).
Status Recent exploration (drilling, geophysics. soil sampling).
Estimated resources Johnny Lee Upper Zone (2013): Measured and Indicated mineral resource of 9,179,000 tonnes with an average grade of 2.83% Cu, 0.12% Co, 0.008 g/t Au and 15.7 g/t Ag and estimated Inferred resource containing 1,255,000 tonnes at an average grade of 2.52% Cu, 0.10% Co, 0.008 g/t Au, and 15.2 g/t Ag (1.6% Cu cutoff); Johnny Lee Lower Zone (2013): Measured and Indicated mineral resource of 2,387,000 tonnes with an average grade of 6.4% Cu, 0.03% Co, 0.304 g/t Au, and 4.5 g/t Ag and estimated Inferred resource containing 205,000 tonnes at an average grade of 5.33% Cu, 0.03% Co, 0.207 g/t Au, and 4.1 g/t Ag (1.5% Cu cutoff); Lowry Middle Zone (2013): Measured and Indicated mineral resource of 4,099,000 tonnes with an average grade of 2.94% Cu, 0.1% Co, 0.006 g/t Au, and 15.1 g/t Ag and estimated Inferred resource containing 801,000 tonnes at an average grade of 2.58% Cu, 0.1% Co, 0.008 g/t Au, and 14.1 g/t Ag (1.6% Cu cutoff) (Winckers and others, 2013).
Geologic maps Reynolds and Brandt (2005, 2006), scale 1:100,000; McClernan (1980), scale 1:250,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Calcareous shale of the lower Proterozoic Newland Formation.
Deposits Johnny Lee Upper Zone, Lower Zone, Lowry Middle Zone (USMIN Site_ID: MT00002).
Evidence from mineral occurrences USMIN.
Geochemical evidence Pyrite occurs as laminations and beds of very fine grained pyrite and marcasite with disseminated and lenticular masses of chalcopyrite and minor bornite, tennantite, cobaltite, and siegenite. Gangue material includes barite, dolomite, calcite, and fine-grained quartz (Winckers and others, 2013).
Geophysical evidence Unknown (no record of geophysics in exploration history).
Evidence from other sources Exploration data-soil and drill sampling and geochemistry.
Comments The Black Butte copper deposits (formerly known as Sheep Creek) are a group of sedimentary rock-hosted, laterally extensive Cu–(Co–Ag) deposits hosted in dolomitic shale of the mid-Proterozoic Newland Formation. In 2020, the hard rock mining permits were approved and construction started for possible mine operation to begin in 2022.
Cover thickness and description Exposed at the surface.
Authors Jane M. Hammarstrom, Kaleb C. Scarberry.
New data needs Geologic mapping, geophysical and geochemical surveys.
Geologic mapping and modeling needs Geologic mapping.
Geophysical survey and modeling needs High resolution aeromagnetic and aeroradiometric coverage.
Digital elevation data needs Lidar planned over northern half of focus area; southern half not covered.