Santo Nino Mine (Santo Niño Mine; North Santo Nino; North Santo Wind; Brooks; Santa Maria Mo Mine), Santo Niño Mine area, San Antonio Canyon, Duquesne-Washington Camp, Patagonia Mining District, Patagonia Mountains, Santa Cruz County, Arizona, USAi

Regional Level Types
Santo Nino Mine (Santo Niño Mine; North Santo Nino; North Santo Wind; Brooks; Santa Maria Mo Mine)	Mine
Santo Niño Mine area	Area
San Antonio Canyon	Canyon
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 surface and underground Cu-Ag-Mo-Au-Pb-Zn mine located on 5 patented claims in the NE¼NW¼ sec. 9, T24S, R16E, on the NE slopes of Mount Washington, on a southern tributary of San Antonio Canyon, 2½ miles SW of Duquesne (Washington Camp), on the east slopes of the Patagonia Mountains, on National Forest land. Discovered 1908 by Dennis Coughlin. Produced 1912-1955. Previous owners/operators include the Miami Copper Co.; Beyerle (1927); the Santo Nino Mining Co. (1926-1931); Young & Gardner (1943); Santo Nino Lessees (1954-1955); the Havalena Mining Co. (1910-1912); A. De La Ossa (1958); and, W.S. Talcott (1959). Owned by the Southern Copper Mining Co., New York (1959). Operated by Utah Construction and Mining Co., Utah International (1970).

The country rock of the area is a fresh gray quartz monzonite with very conspicuous joints. The principal joints strike north to N.10W. and dip 60º to 70ºW., and the secondary joints dip 0º to 10ºN.

Prominent fractures, both mineralized and unmineralized, are found in the mine and on the surface above the mine. The fractures strike N.45º to 50ºE. and dip 60ºN. to vertical. Where mineralized, the fractures may contain pink, feldspathized quartz monzonite, light cream-colored aplite, or pyrite- and chalcopyrite-bearing vein quartz. Where unmineralized, the fractures contain as much as 5 feet of white or limonite-stained gouge and breccia.

The principal ore-bearing formation is a pink feldspar-rich medium-grained granitic rock. The contact between the pink feldspar rock and the gray quartz monzonite country rock is gradational and very irregular and suggests that the feldspar has replaced the quartz monzonite. The principal body of the feldspathized rock is a roughly sheet-like body that averages only a few feet in width, strikes N.10ºW., and dips 70ºW. The maximum thickness observed was about 20 feet, but pocketlike extensions or apophyses extend out from the main mass for more than twice that distance.

Pyrite and chalcopyrite are disseminated through most of the feldspathized rock and for several feet into the adjacent quartz monzonite. Large and small vugs and pockets of massive and terminated quartz are scattered irregularly throughout the feldspathized rock.

Molybdenite is found principally in pockets and lenses that are as much as 10 feet in maximum dimension and are located at irregular intervals in the feldspathized rock. Observed molybdenite pockets were associated with conspicuous joints. The high-grade molybdenite is disseminated for 2 to 3 inches out into the rock surrounding the joints.

Workings included development on 7 levels. The stoped area was about 200 feet long, more than 200 feet high, 30 to 40 feet wide on the stope level, and 5 to 6 feet wide in the upper levels. Worked sporadically from the early 1900's-1955.

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Link to USGS MRDS:	10026908

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References