Bonanza Mine, Westinghouse Mine (Westinghouse property; Davis property), Nash Mines group (Duquesne-Washington group), Duquesne-Washington Camp, Patagonia Mining District, Patagonia Mountains, Santa Cruz County, Arizona, USAi

Regional Level Types
Bonanza Mine	Mine
Westinghouse Mine (Westinghouse property; Davis property)	Mine
Nash Mines group (Duquesne-Washington group)	- not defined -
Duquesne-Washington Camp	Mining District
Patagonia Mining District	Mining District
Patagonia Mountains	Mountain Range
Santa Cruz County	County
Arizona	State
USA	Country

A former small underground Zn-Pb-Ag-Cu-Au-Mo-Mn mine located in NW¼ sec. 2, T24S, R16E (protracted), just north of Duquesne and Duquesne Wash, almost directly N of Duquesne along the W side of Washington Duquesne Road, at an elevation of about 5,400 feet, on private land. This mine is located on the very north edge of the now ghost town of Duquesne. Discovered and located by Thomas Shane and N.H. Chapin in the early 1880's or before. They sold the mine to a Mr. Hensley, about 1889 he sold the mine to the Duquesne Co., which operated it for 2 years. They resumed operations about 1899 and continued for about 3 years. Owned at times, or in part, by the Duquesne Mining & Reduction Co.; Callahan Zinc Lead Co.; Byrd, Elayer & Co.; Sam Knight Mining Lease; and Nash Mines. Previous owners/operators included Mr. George Westinghouse (1889 - Westinghouse Electrical Co. bought the W.C. Davis property, which included the mines of Bonanza, Pocahontis, Pluto & Illinois). Owned by the J. R. Simplot Co. (1966).

Mineralization is sulfides oxidized to a depth of about 100 feet (31 meters), in a garnet-quartz gangue in a large cluster of lensing bodies and bunches along a fault contact of pyrometamorphosed Permian Naco Group limestone and Jurassic-Triassic volcanics. The gossan is manganese-stained. Ore concentration was metasomatic replacement and secondary enrichment following intrusion of volcanics; supergene enrichment of manganese oxides and bornite; and hypogene enrichment of Pb-Zn-Chalcopyrite and Molybdenite. Copper minerals are generally segregated into bunches. Ore lenses 20-25 feet wide are found in the bottom drift; large horizontal or bed-like body of zinc ore was encountered 30 feet below surface, which extends laterally throughout the mine. 75-80 foot thick ore shoots containing considerable zinc begin 60-70 feet below surface. The main ore zone lies between the 435 & 535 foot levels. The ore zone is 91.44 meters long, 7.62 meters wide, with a depth-to-bottom of 182.88 meters, striking N-S and dipping vertically to steeply E. The host rock units are the Naco group; Epitaph Dolomite, Cherty Limestone Member; Scherrer formation, Lower Quartzite Member. Associated rock unit is the Duquesne Volcanics.

The mine is on the contact of the limestone belt of the camp with the intrusive granite porphyry on the east. The deposit trends mainly north and stands about vertical or dips steeply to the east, trending to parallel the contact. The contact and seemingly the limestone or sedimentary rocks dip to the east or outward. Limestone near the contact shows evidence of sheeting or inconspicuous high-angle faulting. Tectonic elements are the N-S-trending Bonanza Fault Zone; the Washington Camp Fault Block to the W and the downthrown Duquesne Fault Block to the east.

The ore deposits occur in the crystalline limestone, mainly in the usual garnet-quartz gangue. Mineral deposits of the Washington-Duquesne area occupy a limestone-sediment belt (2.5 miles long by 1.25 miles wide) surrounded by igneous rocks which also form detached masses and dikes within the belt. Post-mineral faulting displacing ore horizons tens of feet, NW-plunging anticline; two upper ore zones thicken and locally merge to form one ore zone dipping 50°-70° NE along the axis of a NW-plunging anticline. A tectonic feature is the Washington Camp fault block.

At 30 feet below the surface the early operators encountered a large, horizontal or bedlike body of zinc ore
On the 60 foot level occurs a large body of copper sulphide ore. The ore minerals are medium-grained chalcopyrite and sphalerite in a firm garnet-quartz gangue.

Workings include the Bonanza shaft at 635 feet (193.55 meters) with considerable drifting (about 7,000 feet of underground workings on 6 levels. Work comprises about 1,000 feet of shafts, 3,700 feet of tunnels, 1,000 feet of crosscuts, over 100 feet of winzes, and 600 feet of raises. The 635 foot Bonanza shaft has 6 main levels spaced 100 feet apart vertically (first level is 135 feet below surface). Levels in carbonate ore were at 40, 60, and 70 feet. Worked mainly in the early 1900's to 1921, and in 1941 through 1944, and again in 1951 through 1957. Total production would be over 55,000 tons of ore averaging about 7% Zn, 3% Cu, 1% Pb, 4 oz. Ag/T and minor Au. Assay data: The average ore assays 18% Zn, 6% Cu, 1% Pb, 5 oz/t Ag.

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Link to USGS MRDS:	10037101

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References