| Basis for focus area |
15 km buffer around Contact point location from Singer and others (2008). |
| Identified resources |
Identified resources and historical production of copper and gold. |
| Production |
Total production from 1908 to 1978 at the Robinson mine was more than 1.5 million tonnes Cu and 2,700,000 troy oz Au. Commercial production resumed in 2004, with production of 23.6 million lbs Cu and 10,490 oz Au. |
| Status |
Past and current mining. |
| Estimated resources |
Robinson mine in 2006 Proven and Probable reserves were reported as 160,067,000 tons grading 0.69% Cu and 0.007 oz/t Au. |
| Geologic maps |
Brokaw (1967), scale 1:24,000; Brokaw and Barosh (1968), scale 1:24,000; Brokaw and others (1973), scale 1:24,000; Brokaw and Heidrick (1966), scale 1:24,000. |
| Geophysical data |
Inadequate aeromagnetic and aeroradiometric coverage. |
| Favorable rocks and structures |
The Robinson deposit generally follows the typical porphyry copper deposit model in the pattern of alteration and mineralization. associated with emplacement of a quartz monzonite pluton. Additional orebodies formed in adjacent sedimentary rocks. Silty to sandy layers of the Chainman Shale provided initial permeability, enhanced by later faulting. At the Ada, Rob Roy, and Los Angeles deposits, ore formation occurred in a favorable zone bounded by massive Ely Limestone and impermeable Chainman black shales. |
| Deposits |
Robinson mine (MRDS dep_id: 10310402; USMIN Site_ID: NV00130) with 3 open pits; Ruth (MRDS dep_id: 10080427), Tripp-Veteran (MRDS dep_id: 10037318), Liberty (MRDS dep_id: 10037320). |
| Evidence from mineral occurrences |
MRDS; USMIN. |
| Geochemical evidence |
Jasperoids, skarns, and polymetallic veins variably enriched in Bi, Mn, Te, and Zn. Ore horizons are oxidized stratabound blankets of silica-clay-pyrite-rich material. |
| Geophysical evidence |
Unknown. |
| Evidence from other sources |
Gott and McCarthy (1966); Giles and Schilling (1972); Maher (1995). |
| Comments |
The Ely (Robinson) porphyry Cu-Mo-Au deposit, Cu-and Fe-skarns, and precious metal deposits were once part of a contiguous mineralized system of Cretaceous age that was cut up and rotated by Tertiary Basin and Range-type normal faulting. As a result, the district is strongly elongated east-west (approximately 13 by 1 km). |
| Cover thickness and description |
No significant cover. |
| Authors |
David A. John. |
| New data needs |
Geologic mapping, 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. |
