Big Iron

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

Information leading to the delineation of this focus area

Basis for focus area Recent exploration at Big Iron; check other exploration sites that mention W as one of several commodities.
Identified resources Historical production of copper, silver, and zinc.
Production Unknown.
Status Past mining.
Estimated resources Unknown.
Geologic maps Fox (1981), scale 1:24,000; Yates (1971), scale 1:31,680.
Geophysical data 75% mapped at Rank 3 aeromagnetic and Rank 2 aeroradiometric, remaining is inadequate.
Favorable rocks and structures Limestone and graywacke of the Permian Mt Roberts Formation intruded by Jurassic basic sill and Eocene basic and acidic dikes at big iron. At Minorca Eocene intrusions are dacite to rhyodacite with ore occurring a lodes.
Deposits Big Iron mine (MRDS dep_id: 10008903).
Evidence from mineral occurrences MRDS.
Geochemical evidence Unknown.
Geophysical evidence Unknown.
Evidence from other sources Unknown.
Comments Mostly national forest with some state land (mineral leases) and BLM.
Cover thickness and description Exposed at the surface.
Authors Daniel W. Eungard.
New data needs High resolution mapping, geophysics.
Geologic mapping and modeling needs 50% mapped at a scale of 1:24,000 with remainder at scales of 1:48,000 to 1:62:500.
Geophysical survey and modeling needs 75% mapped at QL3 aeromagnetic and QL2 aeroradiometric, remaining is lower QL. Need higher resolution aeromagnetic data as aeroradiometric data likely not useful for this deposit type.
Digital elevation data needs Lidar complete.