Exile King Mine, Helvetia, Helvetia-Rosemont Mining District, Pima County, Arizona, USAi

Regional Level Types
Exile King Mine	Group of Mines (Abandoned)
Helvetia	Town (Former)
Helvetia-Rosemont Mining District	Mining District
Pima County	County
Arizona	State
USA	Country

A former small Cu-Ag-Zn-Pb-Au-W-Mo-U-Be occurrence/mine located in East-central sec. 24, T18S, R15E, G&SRM, 1¾ miles E of Helvetia, near the crest of the range, at about 5,400 feet of altitude, and about 28 miles SE of Tucson. The north end of the Exile claim overlaps the King claim. Adjoins the Broad Top Mine and connects to it with tunnels. Discovered 1899. Owned at times, or in part, by the Rosemont Copper Co.; Rosemont Development Co.; Lewisohn Copper Corp.; Lewisohn Estate; Daylight Mining Co.; Maffeo; the Allison Steel Co.; Alma Greenhalgh; and, Chilson.

This group includes the patented Malachite and Broad Top claims; and, the Cuprite, Vulture, Bonnie Blue, Exile, Blue Point, Aceola, Amole and King unpatented claims.

Mineralization is copper carbonates, oxides, and sulfides with some minor zinc and lead minerals in irregular lenticular zones, stringers and pockets in bedded, pyrometasomatic ore bodies and in massive fracture fillings in silicated Permian limestone along the contact with Laramide quartz latite porphyry stock. Sparsely disseminated scheelite, pods of molybdenite occur in late quartz stringers and small pockets of pitchblende. Ore control was NE-striking fractures along the contact of limestone and quartz latite porphyry. Alteration was silicification of limestone; secondary chloritization, argillization, sericitization, and tremolitization. Host rock units are the Concha Limestone and the Scherrer Formation.

A 12 foot ledge of altered, sheared, silicified, epidotized, mineralized limestone next to the contact with the intrusive alaskite-granite porphyry (?), dipping steeply to the north is exposed by the southern working (King claim). The ledge contains stringers and pockets of oxidized iron and copper ores.

A similar 10 foot wide ore body is exposed north of the first. This ore body dips to the S in an opposite direction to the dip of the adjoining, un-mineralized crystalline limestone. Here the ore consists of malachite, azurite, cuprite, limonite, and a little pyrite and chalcopyrite in a gangue of altered limestone.

About 200 feet farther north again there is a large open cut (100 feet long, 30 feet wide and 20 feet deep) that exposed a 10 foot wide bed of highly altered, very siliceous epidotized and mineralized limestone. The ore consists principally of limonite, malachite, azurite, and cuprite scattered throughout the bed. On some of the joints occurs later quartz which carries pyrite and chalcopyrite.

Local structures include thrust and normal faulting, fracture zones, homoclinal. Regional trends include tilting and broad open folds in the south and extensive faulting in the north.

Workings include surface and underground openings including several short tunnels, the longest about 150 feet in length, with winzes and stopes and open cut operations.

Production was over 55,000 tons of ore averaging about 6% Cu, 1 ounce Ag/ton, and minor Zn and Pb were produced between the early 1900's and 1959.

Other Databases

Link to USGS MRDS:	10039414

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References