Latitude: 32°23'18"N
Longitude: 113°54'33"W
A surface and underground Cu-U prospect located in sec. 9, T12S, R16W, on the NW flank (northern tip) of the Cabeza Prieta Mountains, 25.5 miles SE of Wellton, on a military reservation.
Mineralization is a vein deposit in narrow fissure zones that occur in or adjacent to long, irregular dikes of aplite or pegmatite.
The deposit is a fracture zone that is 64.01 meters long, strikes N.34ºW. & dips 68ºSW in biotite granite. Adjacent to the fracture zione is a quartz-feldspar pegmatite dike that roughly parallels the zone on the hanging wall side.
In the lower adit, the fracture zone is stained along the cracks by copper and iron minerals and seams of malachite & chrysocolla along major fractures.
Workings include 2 short adits & an open cut. The lower adit is about 10 feet long and the upper adit is about 20 feet long. No record of production. A selected sample contained 0.034% U, 7.69% Cu.
At some places in the mine workings, and on the dumps, radioactivity is as much as five times the background radioactivity. A stockpile of copper-stained material presumably mined from one of the adits gave readings of nearly 0.5 MR per hour on a scintillation meter. Although it is possible that the McMillian prospect contains local concentrations of uranium ore, most of the radioactive rock on the property is below commercial grade.
References
Wilson, E.D. (1933) Geology and Mineral Deposits of Southern Yuma County, Arizona. Arizona Bureau of Mines Bulletin 134: 163.
Granger, H.C. & R.B. Raup (1962), Reconnaissance study of uranium deposits in Arizona, USGS Bull. 1147-A: A48-A49.
MRDS database Dep. ID file #10027214, MRDS ID #M002497.
Mineral List
3 entries listed. 2 valid minerals.
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