Hardshell Mine, Hardshell Gulch, Harshaw, Harshaw Mining District, Patagonia Mountains, Santa Cruz County, Arizona, USAi

Regional Level Types
Hardshell Mine	Mine
Hardshell Gulch	Gulch
Harshaw	- not defined -
Harshaw Mining District	Mining District
Patagonia Mountains	Mountain Range
Santa Cruz County	County
Arizona	State
USA	Country

A former small surface and underground Pb-Ag-Mn-Cu-Zn-Au occurrence/mine located in the center of sec. 4, T23S, R16E (protracted) on 42 claims, in Hardshell Gulch, at the foot of the steep southerly slope from Table Mountain, about 1 mile SW of Harshaw, a short distance West of Hermosa, on the easterly slope of the Patagonia Mountains, at 5,150 feet of altitude, on private (patented) land. Discovered by David Harshaw and José Andrade in 1879. Produced 1896-1964. Owned at times, or in part, by Mr. R.R. Richardson (1880-1890; 1895-1896; 1897-1901); Mr. Heney of Tucson (1905- ); the Empire Mining & Milling Co. (Mr. Fitzgerald; Columbia Co.)(1896- ); Hardshell Mining Co.; Gardner & Young; Bender; Big Jim Mines, Inc.; Valenzuela; McFarland; and, the American Smelting & Refining Corp. (ASARCO).

Mineralization is irregular, lensing ore bodies and ore shoots of ferruginous and manganiferous, argentiferous cerussite, complex lead and zinc oxidation products, chlorargyrite and other silver halides, and spotty copper and gold as replacement of fault gouge and silicified fault breccia in a strong fault zone. The ore zone is 460 meters long, 275 meters wide and 18 meters thick, strikes E-W and dips 35N. The shear zone is about 300 feet long and 30 feet wide. Wall rocks are Jurassic-Triassic volcanics and Cretaceous andesite with thin interbedded limestone, shale, and conglomerate. Some spotty, high-grade manganese oxide areas. Cretaceous dioritic and andesitic dikes are present. Generally weak base metal sulfides found in depth.

Rocks which underlie the Hardshell group of claims are limestone, quartzite, conglomerate and intrusive rhyolite and felsite. In the mine the rhyolite and felsite are the dominant rocks, but there are also beds of quartzite and limestone.

The Hardshell Mine explores a shear zone that strikes NE and dips NW at angles varying from a few degrees to 35º. The shear zone ranges from a few feet to 60 feet or more in width and the ore deposits occur rather irregularly in it but with a persistent vein along its footwall.

The material of the shear zone is greatly crushed quartzite, rhyolite, felsite, a persistent band of kaolinized material and the ore, consisting of lead carbonate and subordinate galena associated with iron and manganese oxides. The iron and manganese oxides are generally separate. In some places the manganous ore is 6 feet wide and fairly persistent but elsewhere it occurs as bunches and stringers and in nodular masses disseminated in kaolinized material. Oxidized lead ore is intimately associated with the manganese deposits.

Local structures include the Corral Canyon fault block with downthrow to the SW. Located on the N-S-trending American fault.

Workings include a 600 foot deep inclined shaft on the dip and drifts on several levels which extend about 200 feet East of the incline and about 75 feet West of it. Workings attain a vertical depth of 250 feet. Workings aggregate some 3,000 feet of openings. Worked from about 1896 through 1964. Produced some 35,000 tons of ore averaging about 6% Pb, 8 ounces Ag/ton, 0.5% Cu and minor Zn and Au; and about 1,000 tons of Mn ore and concentrate averaging about 40% Mn. Reserve has a refractory metallurgical problem due to Mn.

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Link to USGS MRDS:	10103551

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