| Basis for focus area |
Polygons extracted and merged from National Assessment tract NR48, previously categorized as Homestake stratiform Au (Long and others, 1998). |
| Identified resources |
Indicated resources of gold. Historical production of arsenic, copper, gold, lead, silver, and tungsten. |
| Production |
Past production: 1,916,000 total metric tons ore, yielding 14 metric tons Au, 1 metric ton Ag, negligible Cu and Pb, and unknown amounts of As and W (Long and others, 1998). Production included over 200,000 oz Au, with Ag, As, and W before 1948. Approximately 240,000 oz Au from 1800s to 1948. From 1989 to 1996: 270,000 oz Au from a 430,000 oz Au resource at Crevice Mountain deposit. |
| Status |
Past mining; mines are currently shut down and reclaimed. |
| Estimated resources |
Estimate of 1,295,000 total tons of ore including 12 metric tons Au (Long and others, 1998). |
| Geologic maps |
Ruppel and others (1993), scale 1:250,000; Kellogg and Williams (2005), scale 1:100,000; O'Neill and Christiansen (2004), scale 1:100,000; Berg and others (1999), scale 1:100,000. |
| Geophysical data |
Inadequate aeromagnetic and aeroradiometric coverage. |
| Favorable rocks and structures |
Stratabound Au in iron-formation. Mineralization is hosted by 3.0 to 3.2 Ga lower amphibolite facies grunerite-bearing banded iron-formation and metaturbidites on the Wyoming Craton. Three types of ore have been mined: 1) dominant style where Au is contained in marginal wall rock altered envelopes of arsenopyrite, pyrrhotite, hornblende and grunerite sandwiching 0.01 to 1 m-thick quartz veins within iron-formation; 2) in generally less than 5 m thick banded quartz veins with little or no accompanying wall rock alteration; and 3) in deformed quartz boudins. |
| Deposits |
Mineral Hill mine (Jardine mine) (MRDS dep_id: 10245632). |
| Evidence from mineral occurrences |
MRDS. |
| Geochemical evidence |
Arsenopyrite veins associated with cummingtonite. Arsenopyrite, pyrrhotite, pyrite, and scheelite accompany Au mineralization. |
| Geophysical evidence |
Unknown. |
| Evidence from other sources |
Unknown. |
| Cover thickness and description |
Unknown. |
| Authors |
Allen K. Andersen, Kaleb C. Scarberry. |
| New data needs |
Geologic mapping, geophysical, and geochemical surveys. |
| Geologic mapping and modeling needs |
Targeted 1:24,000 mapping and mine-site mapping. |
| Geophysical survey and modeling needs |
High resolution, Rank 1 aeromagnetic and aeroradiometric coverage. |
