Keystone Mine (Hagerman Mine; Hagerman shaft; Bannon group), Dragoon, Cochise Mining District, Cochise County, Arizona, USAi

Regional Level Types
Keystone Mine (Hagerman Mine; Hagerman shaft; Bannon group)	Mine
Dragoon	Village
Cochise Mining District	Mining District
Cochise County	County
Arizona	State
USA	Country

A former small underground Cu-Zn-Ag-Mo-Au-Pb-W mine located in North-central sec. 36, T.15S., R.22E, on 16 claims, ¾ mile SE of the town of Johnson, 6 miles N of Dragoon, and 1.1 km SW of the Republic Mine, on private land. Discovered 1908. Produced 1915-1958. Owned/operated in part, or at times, by the Black Prince Copper Co.; Keystone Copper Mining Co.; Aztec Mining & Development Co.; Strong & Moseley; and, the Coronado Copper & Zinc Co.

Claims ?: Wolfrime, Ultimo, Roswell, O.K., Nevertheless, Maher, Louie, Ina, Gustave, Hagerman, Halderman, Gladys, Erika, Ernest, Esmeralda, Ella, Dora, Charles, Calumet, and Mary.

Mineralization is a replacement deposit of copper, zinc, and spotty molybdenite mineralization in pyrometasomatic tabular, chimney and mantos ore bodies in the Abrigo Formation, Devonian Martin and Mississippian Escabrosa limestones. Strong garnetization. Also, spotty molybdenite in Cambrian Abrigo Limestone. An associated rock unit is the Texas Canyon Quartz Monzonite (Stock). Ore control was favorable beds cut by a fault. Alteration is metamorphosed to tactite characterized by diopside, tremolite, K-feldspar and quartz. Assay results from drilling indicates: 0.6-1.2% Cu, 0.9 foot bed of 4.1% Mo, 7 foot of 1.02% Mo.

Most ore came from upper levels in the Martin & Escabrosa formations. Abrigo formation mineralized sporadically in vicinity of inferred fault. Molybdenite occurs in the Abrigo. Ore occurs along the plane of the beds and ore bodies have their long axis parallel to the dip of the beds.

Local structures include Tertiary block faulting, Lower Cretaceous or Early Tertiary N- and NW-trending folds and thrust faulting, N63E normal fault dips 36SE. Also the Keystone Fault with a horizontal displacement of about 1,200 feet (360 meters).

Workings include a shaft(s) and total 396.24 meters in length. Drilling was conducted by the U.S.Bureau of Mines. The vertical shaft is 650 feet deep, with levels at 60, 200, 325, 487, & 565 feet below surface. The main perpendicular Hagerman shaft consists of two vompartments, beginning at the third level. Stations and ore pockets have been cut 100 feet apart. The OK shaft is an incline with an average inclination of 34 degrees and measures 385 feet from the collar to the bottom. There are several other vertical and inclined shafts tens of feet deep with numerous pits and small open stopes. The length of the workings is estimated.

A total of about 2,250 tons of ore were produced intermittently from 1917 to 1958.

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Link to USGS MRDS:	10039383

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References