Mineral Farm Mine (Mineral Farms group; Mineral Farm group; Moonlight & Mineral Farm group; Eagle Pass group of claims; Moonlight; Bennett), Big Johnnie Gulch, Copper Hill, Globe Hills, Globe Hills District, Globe-Miami District, Gila Co., Arizona, USA
Latitude: 33°26'47"N
Longitude: 110°46'11"W
A former surface Mn-Cu-Ag-Zn-Pb mine on a group of 21 manganese claims located in the SW¼ sec. 10, T1N, R15E, near the head of Big Johnnie Gulch, 0.3 miles N of Black Peak, just N of the Copper Hill ghost town and about 3 miles North of Globe, East of the Superior and Globe Comm. Copper Company's properties, on private land. Discovered 1878 and produced 1918-1953. The Moonlight & Mineral Farm group was originally part of 21 claims called the Mineral Farm or Eagle Pass group, including Big Iron, Vacey Constance & Iron Hive groups. The complexte group was operated by Mineral Farm Co. in the 1900's; Globe Mining (1913); and Moline & Arizona (1917). Ten of the Moonlight-Mineral Farm claims currently owned by John R. Bacon (1951) & by F.A. Sitton.
Mineralization is a group of small veins of manganous iron ore that crop out about ½ mile NW of Black Peak in a sill-like body of diabase intruded into the lower part of the Pioneer formation The basement rock in this area is Pinal schist. The veins are along a network of branching fissures that strike N20E to east and dip 45NW to vertical. They range in size from thin stringers and inch or two (2.5 to 5 cm) wide to zones of partly replaced breccia 6 feet wide. They cut diabase & quartzite. The veins were formed by replacement of gouge and angular breccia fragments along the fissures. The ore zone is 152.4 meters long, 1.83 meters wide, strikes N80E and dips 60NW.
The vein matter is completely oxidized and consists of porous and honeycombed quartz and angular fragments of altered and partly replaced diabase with ribs of hard "psilomelane-like" minerals and pockets of soft, earthy oxides of Mn & Fe. Many vugs are filled with crystals of manganite., and some manganite occurs with the earthy oxides.
The most abundant vein minerals are quartz, carbonates and sulfides. The sulfides are closely associated with, and appear to replace, the carbonates, which are cut by veinlets of quartz. Specular hematite is intergrown with the quartz, and also with all the sulfides, particularly sphalerite.
The above description is for the Mn deposit. The Cu-Ag deposit (Yuma vein) strikes N40E and dips steeply NW.
Workings include a 215 foot deep shaft and many shallow pits less than 5 feet (150 cm) deep. The developments reach a depth of 365.76 meters. The Yuma vein has been developed by a 1200 foot deep shaft and a 160 foot tunnel. Production is from the Moonlight vein & the Mineral Farm claims No. 4. Most of the manganese production is from shallow pits and open cuts. Mineral Farm Co. is said to have shipped Ag ore; Moline & Arizona shipped Cu-Ag ore. John R. Bacon (1951) & F.A. Sitton both shipped Mn ore.
References
Jones, E.L., Jr. & F.L. Ransome (1920), Deposits of manganese ore in Arizona, USGS Bull. 710-D: 168-169.
Wilson, E.D. & G.M. Butler (1930), Manganese ore deposits of Arizona, Arizona Bureau of Mines Bull. 127: 59, 62.
Farnham, L.L., Stewart, L.A., and Delong, C.W. (1961), Manganese Deposits of Eastern Arizona, US Bureau of Mines Information Circular 7990: 59.
Peterson, N.P. (1962), Geology and ore deposits of the Globe-Miami district, Arizona, USGS PP 342: 70, 74, 131.
Arizona Department of Mineral Resources Moline and Arizona file.
U.S. Bureau of Mines - Arizona Bureau of Geology and Mining Technology file data.
MRDS database Dep. ID #10027475, MRDS ID #M003167; and Dep. ID #10282749, MAS ID #0040070039.
Mineral List
15 entries listed. 13 valid minerals.
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