| Basis for focus area |
Productive vein traces; Black Hawk district boundary (McLemore, 2017). |
| Identified resources |
Historical production of copper, fluorite, gold, silver, and tungsten. |
| Production |
Silver, Au, Cu, Pb, F (615 tons); W produced from 1881-1893; W production: 10,542 lbs of 2.7-7.7% WO3. Recurrent exploration work in 1917 and some exploration focused on U, Ni, and Co from 1949-1952; additional exploration 2010 to present (production data from https://geoinfo.nmt.edu/staff/mclemore/documents/tungsten.xls). |
| Status |
Past mining. Past producers purchased by Sante Fe Gold Corp. on April 3, 2019; current exploration. |
| Estimated resources |
Possibly 1,000 short tons ore remains in the faces as Black Hawk, Alhambra, and Rose mines closed in 1893 (production data in McLemore, 2017). |
| Geologic maps |
Gillerman and Whitebread (1956, plate 14), scale 1:8,100; Hedlund (1978b), scale 1:24,000; Drewes and others (1985), scale 1:250,000. |
| Geophysical data |
Adequate but unpublished aeromagnetic and radiometric coverage. The area is entirely covered by aeromagnetic and aeroradiometric coverage collected on a 1000-foot grid, so Rank 1, but the coverage is unpublished. USGS can study it, but can't publish the coverage, only a map derived from it, and cannot give coverage to the states. Other than that, inadequate coverage. |
| Favorable rocks and structures |
Fissure veins that pinch and swell along strike with steep dip, and northerly to easterly strike. Precambrian quartz diorite gneiss is a preferred host rock. |
| Deposits |
Black Hawk mine (MRDS dep_id: 10067835; USMIN Site_ID: NM00041), Alhambra mine (MRDS dep_id: 10101798), Rose mine (MRDS dep_id: 10013296), Silver King (Hobson) mine (MRDS dep_id: 10097907), Good Hope mine (MRDS dep_id: 10014643). |
| Evidence from mineral occurrences |
MRDS; USMIN; McLemore (2017). |
| Geochemical evidence |
Very limited dump-, select-, grab-sampling from Gillerman and Whitebread (1956, p. 301) gave mean values from 5 ore samples (only 3 analyzed for U3O8) of 0.153% U3O8, 1.28% Ni, 0.23% Co, and 13.06 oz/st Ag. |
| Geophysical evidence |
All of the focus area is covered by aeromagnetics and aeroradiometric data collected on a 1,000-foot grid, so Rank-1, but the data are unpublished. Also available are NURE data with 3-mile line spacing. |
| Evidence from other sources |
New Mexico Mining and Minerals Division mine permits. |
| Comments |
Fluid inclusion studies of Gerwe (1986) and Gerwe and Norman (1984) yielded results consistent with other Five-element Vein-type systems. Temperatures (homogenization) were relatively high from 189 to 404 degrees Celsius with scattered high salinities among dominant more dilute results. |
| Cover thickness and description |
Veins were discovered in outcrop. |
| Authors |
Timothy S. Hayes, Lukas Zurcher, Virginia T. McLemore. |
| New data needs |
Ground EM surveying on a tight grid (100-m, perhaps) would directly target ore shoots within 16 additional mapped "silver, nickel, or cobalt-bearing veins" from Gillerman and Whitebread (1956, Plate 14). Geochemical studies are needed of the ore and host rock. |
| Geologic mapping and modeling needs |
Hedlund maps excellent, but need digitizing. |
| Geophysical survey and modeling needs |
Geophysics needed to make better assessment and to help industry. |
| Digital elevation data needs |
Probably needs lidar coverage. |
