Latitude: 31°53'22"N
Longitude: 109°57'45"W
Ref.: Mahoney, C.G. (1942) U.S. Bureau of Mines, unpublished War Minerals Memo on the Middlemarch Copper Mine: 4.
Gilluly, James (1956) General geology of central Cochise County, Arizona, with sections on age and correlation, by A.R. Palmer, J.S. Williamson, and J.B. Reeside, Jr.: U.S. Geological Survey Professional Paper 281, 169 p., 13 sheets, scale 1:62,500: 80-81.
Keith, Stanton B. (1973), Arizona Bureau of Geology & Mineral Technology, Geological Survey Branch Bull. 187, Index of Mining Properties in Cochise County, Arizona: 68 (Table 4).
Sousa, F.X. (1980) Geology of the Middlemarch mine and vicinity, central Dragoon Mountains, Cochise County, Arizona: Tucson, University of Arizona, M.S. thesis, 107 p.
Innes, D.G. and Associates, Ltd. (1982) unpublished geology report on the Middlemarch property, part of ADMMR files: 2.
Chatman, M.L. (1993) U.S. Bureau of Mines Open File Report Mineral Land Assessment (MLA) 30-93: 23-24, D79.
MRDS database Dep. ID file #10104061, MRDS ID #M241057; and, Dep. ID #10161238, MAS ID #0040030067.
A former small underground Cu-Zn-Ag mine located in the SE ¼ sec. 2, and the NE ¼ sec. 11, T.18S., R.23E, approximately 11 miles NW of Courtland. First produced 1915. Owned at times, or in part, by the Cobre Loma Copper Co., Middlemarch Copper Co., and the Arizona Middlemarch Copper Co.
Mineralization is sulfides in a pyrometasomatic tactite zone in limy hornfels of Cretaceous Bisbee Group along the contact with a porphyritic intrusive east-dipping, NW-trending thrust sheets, near the Cobre Loma thrust fault that bounds the main mass of Cochise Peak Quartz Monzonite, ½ mile (0.8 km) South of Cochise Peak. The porphyritic intrusive was mapped as rhyolite by Sousa, 1980.
Local structures include steep dipping to overtruned Cretaceous beds. These beds dip 30-60SW in the area of the thrust fault.
Workings include tunnels. Probably up to 5,000 tons of ore were produced from 1915 to 1920.
Mineral List
11 entries listed. 11 valid minerals.
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