Contention-Grand Central Mine group, Tombstone District, Tombstone Hills, Cochise Co., Arizona, USA

Ref.: Blake, W.P. (1882) The geology and veins of Tombstone, Arizona: American Institute of Mining Engineers, Transactions: 10: 342-343.

Church, J.A. (1903) The Tombstone, Arizona, mining district: American Institute of Mining Engineers, Transactions: 33: 4, 8, 11-12, 16, 18-20, 23-25, 28, 33-34.

Butler, B.S., Wilson, E.D., and Rasor, C.A. (1938b), Geology and ore deposits of the Tombstone district, Arizona, Arizona Bureau of Mines Bull. 143: 41, 43-45, 69-71, Pl. IV, VIII, IX.

Keith, Stanton B. (1973), Arizona Bureau of Mines Bull. 187, Index of Mining Properties in Cochise County, Arizona: 74 (Table 4).

Niemuth, N.J. (1987), Arizona Mineral Development 1984-1986, Arizona Department of Mines & Mineral Resources Directory 29, 46 pp.

Arizona Department of Mines & Mineral Resources (1989) Directory of Active Mines in Arizona, Incorporating Sand and Gravel Operations (1989-1990): Arizona Department of Mines and Mineral Resources Directory 36, 14 pp.

U.S. Bureau of Mines - Arizona Bureau of Geology and Mineral Technology file data.

Arizona Bureau of Mines files.

MRDS database Dep. ID file #10048228, MRDS ID #M800323; and, Dep. ID #10258539, MAS ID #0040030590.

A former medium-output surface and underground Ag-Au-Pb-Cu-Zn group of mines located in the SE ¼ sec. 11 & the NE¼NE¼ sec. 14, T.20S., R.22E, 1 mile S of Tombstone, on private land. Discovered and started producing in 1885. Owned at times, or in part, by the Western Mining Co., Grand Central Mining Co., Tombstone Mill & Mining Co., Head Center Co., Head Center & Tranquility Co., Contention Mining Co., Tombstone Consolidated Mines Co., Bunker Hill Mines Co., and the Tombstone Development Co. Operated by the Cochise Silver Mines Inc. (1987); and, Cowichan Resources Inc. (1989). The Grand Central Mine is often referred to as part of this mine due to common ownership.

Mineralization is oxidized argentiferous and auriferous galena and minor copper and zinc ores in large, rich orebodies in faulted and fractured segments of a large dike, and in brecciated footwall zones of the dike. Ore was also found in replacements of Cretaceous Bisbee Group limestone beds where intersected by "northeast" fissures. The ore zone is 1005.84 meters long, 304.8 meters wide, with a depth to bottom of 243.84 meters. The Bisbee Limestone is recrystallized. An associated rock unit is the Schiefflin Granodiorite.

Local structures include the Tombstone Basin; NE-trending fissures, and NW-trending faults. The Contention Dike is faulted by a series of NW-trending normal faults.

Workings included extensive shaft(s) and had a total length of 3048 meters and a depth of 243.84 meters. This mine had 3 shafts: the Central shaft, the Pump shaft, used for UTM 1000 feet north of the Grand Central shaft. 10 levels of workings. The workings described here are in the Contention, Head Center, and Flora Morrison claims only. The main workings were in the upper 500 feet, the 6th level is the most extensive. One of the earliest and most productive mine groups of the district. Over $10,000,000 was produced prior to 1886 and several hundred thousand tons were produced from the 1880's to the early 1900's. There was some sporadic production up to 1929. Most productive ore zone of the district when combined with the Grand Central Mine. See the Grand Central for production after 1885 in ABGMT-USBM file data. Workings in 3 claims described here: Flora Morrison, Contention, and the Head Center. This mine was under development to leach dump and tailings material in 1987. This was an open pit-cyanide heap leaching operation in 1989.