| Basis for focus area |
The focus area encompasses the Como and Little Falls Mo resources; REE, Re, W, Sn are potential byproducts. These deposits constitute a Climax-type porphyry cluster. A 15 km buffer was applied to these deposits to encompass undiscovered occurrences in adjacent areas. |
| Identified resources |
Indicated resources for copper, molybdenum, rhenium, silver, and tungsten. Historical production of gold. |
| Production |
Recorded Au production of 2.8 million oz (Arseneau and others, 2020). |
| Status |
Past mining; active exploration. |
| Estimated resources |
CuMo Project: Resources estimates for Mo, Cu, Ag, and Re in Arseneau and others (2020). Tungsten resource estimate given in Giroux and others (2015). |
| Geologic maps |
Kiilsgaard and others (2001), scale 1:100,000. |
| Geophysical data |
Inadequate aeromagnetic and aeroradiometric coverage. |
| Favorable rocks and structures |
Large, low-grade Mo and Cu porphyry deposits are located at the southwestern end of the Idaho-Montana Porphyry Belt; Tertiary, northeast-trending rhyolite dikes cut the Idaho batholith with siliceous pyritic zones containing molybdenite (Worthington, 2007). |
| Deposits |
CuMo Prospect (MRDS dep_id: 10078685; USMIN Site_ID: ID00047), Little Falls. |
| Evidence from mineral occurrences |
MRDS; USMIN. |
| Geochemical evidence |
CuMo was a geochemical discovery; a weathered surface of supergene argillic alteration provided a strong Cu and Mo soil anomaly (Worthington, 2007). |
| Geophysical evidence |
Unknown. |
| Evidence from other sources |
Unknown. |
| Cover thickness and description |
Exposed at the surface. |
| Authors |
Ryan D. Taylor, Albert H. Hofstra. |
| New data needs |
Geophysics. |
| Geologic mapping and modeling needs |
None requested at this time. |
| Geophysical survey and modeling needs |
High-resolution, Rank 1 aeromagnetic and aeroradiometric surveys. |
| Digital elevation data needs |
Lidar complete in southern third of focus area; in progress in northern two thirds. |
