| Basis for focus area |
Polymetallic (Cu-Ag-Au-Pb-Sn) vein and breccia deposits mostly in Oligocene rhyolite, a mined Ag(-Sn) deposit in Oligocene rhyolite, elevated Ag and Sn concentrations in rhyolite (presumably Oligocene) and cassiterite in Au placers. Tin production (cassiterite) from mines on Majuba Hill; placer cassiterite in Rosebud Canyon and Rabbit Hole, north and northwest of Majuba Hill; stannite in drill hole cuttings from the Trinity Silver mine; elevated Sn concentrations in altered rhyolites, Trinity Silver mine and Trinity Range south of Majuba Hill. |
| Identified resources |
Historical production of copper, lead, silver, tin, and zinc. |
| Production |
Majuba Hill area mines (1906-1951): total production as compiled was approximately 2.8 million lbs Cu, 184,000 oz Ag, 885,800 lbs Pb, 106,000 lbs Zn, and 21,000 lbs Sn (Stevens, 1971). |
| Status |
Past mining. The USBM and 6 exploration companies have drilled the Majuba Hills area. |
| Estimated resources |
Unknown. |
| Geologic maps |
MacKenzie and Bookstrom (1976), scale 1:3,600; Johnson (1977), scale 1:250,000. |
| Geophysical data |
Inadequate aeromagnetic and aeroradiometric coverage. |
| Favorable rocks and structures |
Shallow rhyolitic intrusive complex appears to be at a structural intersection between dike-filled north-northeast and west-northwest fault zones. |
| Deposits |
Majuba Hill mine (MRDS dep_id: 10042468), Trinity Silver mine (MRDS dep_id: 10042483), Esther mine (MRDS dep_id: 10042473), Rabbit Hole placers (MRDS dep_id: 10042453), Rosebud gold mine (MRDS dep_id: 10310434). |
| Evidence from mineral occurrences |
MRDS. |
| Geochemical evidence |
Geochemistry of the Majuba Hill intrusives reported anomalously high contents of U, Th, B, As, Bi, Au, Ag, and Li (Wenrich and others, 1984). |
| Geophysical evidence |
Unknown. |
| Evidence from other sources |
Morris (2017). |
| Comments |
First production at the Majuba Hill mine was for Cu and Sn. |
| Cover thickness and description |
Fairly well exposed, but potential for covered deposits on the pediment on both sides of the Trinity Range, especially the western side. |
| Authors |
John L. Muntean. |
| New data needs |
Mapping, petrography, biogeochemistry, geochronology, geophysics. |
| Geologic mapping and modeling needs |
Updated geologic mapping. |
| Geophysical survey and modeling needs |
High-resolution, Rank 1 aeromagnetic and aeroradiometric surveys. |
| Digital elevation data needs |
Lidar in progress (GeoDAWN). |
