Red Lodge chromite

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

Information leading to the delineation of this focus area

Basis for focus area Description of Red Lodge chromite district by Simons and others (1979), prior production.
Identified resources Identified resources and historical production of chromium (chromite).
Production 43,800 tons chromite ore mined from the Hellroaring Group and 24,000 tons from the Highline Group in the 1940s (Simons and others, 1979).
Status Past mining; no current mining or exploration.
Estimated resources Some chromite-bearing lenses completely mined out; ~77,000 tons of chromite ore containing 12.8% Cr2O3 is estimated to remain (Simons and others, 1979).
Geologic maps Lopez (2001), scale 1:100,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Chromite-bearing lenses of serpentinized ultramafic rocks.
Deposits Highline group (MRDS dep_id: 10221207), Gallon Jug No. 4 (MRDS dep_id: 10148891), North Star claim (MRDS dep_id: 10220476), Little Nell group (MRDS dep_id: 10269888).
Evidence from mineral occurrences MRDS; Simons and others (1979).
Geochemical evidence Stream-sediment analyses in Simons and others (1979).
Geophysical evidence Unknown.
Evidence from other sources Chromite-bearing serpentine found at the surface, guide for prospecting.
Comments Relatively small and low-grade deposits compared to nearby Stillwater Complex. PGE, cobalt, and nickel deemed sub-economic (Loferski, 1986).
Cover thickness and description Exposed at the surface.
Authors Jane M. Hammarstrom, Jay A. Gunderson.
New data needs Compilation and integration of data from lidar, airborne geophysics, outcrop maps, and underground workings, lidar.
Geologic mapping and modeling needs Document and map marker beds; look for evidence for out-of-geochronology-sequence map units; 3D modeling of layers and structure.
Geophysical survey and modeling needs High resolution airborne surveys where magmatic unconformities are suspected.
Digital elevation data needs Lidar complete only over northeast section of focus area; incomplete elsewhere.