Black Dike Mine (Black Dike group; Black Dike claim; Black Dike deposit; Black Dyke Mine; Big Dike; Bobson group; Big Dike Apex & Ajax), Papago Mining District (Sierrita Mining District), Sierrita Mountains, Pima County, Arizona, USAi

Regional Level Types
Black Dike Mine (Black Dike group; Black Dike claim; Black Dike deposit; Black Dyke Mine; Big Dike; Bobson group; Big Dike Apex & Ajax)	Mine
Papago Mining District (Sierrita Mining District)	Mining District
Sierrita Mountains	Mountain Range
Pima County	County
Arizona	State
USA	Country

‡Ref.: Ransome, F.L. (1922), Ore deposits of the Sierrita Mountains, Pima County, Arizona, USGS Bull. 725-J: 407-428.

Wright, R.J. (1950) Reconnaissance of Certain Uranium Deposits in Arizona, U.S. Atomic Energy Commission RMO-679.

US Atomic Energy Commission Preliminary Reconnaissance Report Pima County (1951): 627, 631, 632, 637.

Wilmarth, V.R., et al (1952), Uranium in fluorite deposits, USGS Circular 220: 13-18.

McKelvey, V. (1955), Search for uranium in the U.S., USGS Bull. 1030-A: 26-27.

Farnham, L.L., Stewart, L.A., and Delong, C.W. (1961), Manganese Deposits of Eastern Arizona, US Bureau of Mines Information Circular 7990.

Granger, H.C. & R.B. Raup (1962), Reconnaissance study of uranium deposits in Arizona, USGS Bull. 1147-A: A25-A29.

Van Alstine, R.E. and Moore, R.T. (1969) Fluorspar, in USGS & Arizona Bureau of Mines & U.S. Bureau of Reclamation, Mineral and Water Resources of Arizona, Arizona Bureau of Mines Bull. 180 (USGS Bull.871): 353.

U.S. Atomic Energy Commission RME-159 (1970) Preliminary Reconnaissance for Uranium in Pima and Pinal Counties, Arizona, 1950 to 1957: 6-12.

Elevatorski, E.A. (1971), Arizona Fluorspar, Arizona Department of Mineral Resources, U.S. Bureau of Mines Report of Investigation 5651: 33-34.

Krieger, M.H. (1973) Field Examination (Black Dike Mine).

Keith, Stanton B. (1974), Arizona Bureau of Geology & Mineral Technology, Geological Survey Branch Bull. 189, Index of Mining Properties in Pima County, Arizona: 132 (Table 4).

Phillips, K.A. (1987), Arizona Industrial Minerals, 2nd. Edition, Arizona Department of Mines & Minerals Mineral Report 4, 185 pp.

Peirce, H. Wesley (1990), Arizona Geological Survey Industrial Minerals card file.

MRDS database Dep. ID file #10039556, MRDS ID #M050276; and, Dep. ID #10186773, MAS ID #0040190126; and, Dep. ID #10208011, MAS ID #0040190120; and, Dep. ID #10210581, MAS ID #0040190032.

A former small surface and underground Cu-Fluorspar-U-Pb-Ag-Mn-W prospect/group of 5 patented claims located in secs. 23, 24, 25 & 26, T.17S., R.10E. (and/or: the SE¼SE¼ sec. 23, T.17S., R.10E.), on the western flank of the Sierrita Mountains, about 27 miles SSW of Tucson. This property is on ranchland owned by Col. Moller of Tucson (private property). Operated by Ybarra, Allen & Wilson.

Mineralization is a contact metamorphic deposit of spotty and weak copper staining, pyrite, chalcopyrite, and disseminated fluorite with locally admixed manganese and sooty pitchblende in irregular and lenticular ore bodies along fracture veins. Ore control was irregular fractures extending out from the dike contact. Radioactive material is in those parts of the contact, metamorphic zone richest in sulfides and fluorite. The deposit is near the contact zone between the gneissic granite and the metamorphosed sedimentary rocks (or between Mesozoic granite and a basaltic dike). The metamorphic rocks strike N.0º-20ºW. and dip steeply Eastward. The mine is in gneissic granite that is cut by a small, intensely bleached and altered basalt (?) dike, averaging 2 feet wide and is highly altered. Outcrop of silicified schist with thin coating of Mn oxide gives appearance of a large deposit. The ore body is 1.22 meters wide, 12.19 meters depth to top and 45.72 meters thick. It strikes N10W and dips 65E.

Samples from the dike contained less than 0.006% U; from the contact metamorphic zone 0.011 to 0.16% U; and, for copper the range was 0.01 to 0.97% - lowest in the dike.

The lower West slope of the Sierrita Mountains in the vicinity is intricately cut by dry washes and has a rough rolling topography. The western flank is composed of steeply-dipping metamorphosed sandstone, limestone, shale, rhyolite, tuff, and conglomerate, comprised largely of Tornado Limestone (Pennsylvanian-Mississippian) or Martin Limestone (Devonian), and the Lower Cretaceous Comanche series. The core of the Mountains is largely composed of granite and granite gneiss.

Workings include a shaft, sunk originally for Cu in WWI, then for U in 1950's. Workings are 22.86 meters deep. No known production but production was probable during WWI for Pb, Ag, Cu. Local concentrations of uranium minerals could be found but likelyhood of a large, high-grade deposit is weak. More work has been done since the Bull. 1147 report.

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Link to USGS MRDS:	10039556

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