San Xavier Mine (San Xavier Mine shaft), Pima Mining District (Olive Mining District; Mineral Hill Mining District; Twin Buttes Mining District), Sierrita Mountains, Pima County, Arizona, USAi

Regional Level Types
San Xavier Mine (San Xavier Mine shaft)	Mine
Pima Mining District (Olive Mining District; Mineral Hill Mining District; Twin Buttes Mining District)	Mining District
Sierrita Mountains	Mountain Range
Pima County	County
Arizona	State
USA	Country

‡Ref.: Ransome, F.L. (1922) Ore deposits of the Sierrita Mountains, Pima County, Arizona, in Contributions to Economic Geology (Short Papers and Preliminary Reports), 1921 - Part I.--Metals and Nonmetals except Fuels: U.S. Geological Survey Bulletin 725, p. 422-423.

Mayuga, M.N. (1942) The Geology and Ore Deposits of the Helmet Peak Area, Pima County, Arizona, PhD thesis, University of Arizona.

Wilson, E.D., et al (1950), Arizona zinc and lead deposits, part I, Arizona Bureau of Mines Bull. 156: 43, 46-47.

Keith, Stanton B. (1974), Arizona Bureau of Geology & Mineral Technology, Geological Survey Branch Bull. 189, Index of Mining Properties in Pima County, Arizona: 137 (Table 4).

Elevatorski, E.A. (1978), Arizona Industrial Minerals, Arizona Department of Mineral Resources, Minerals Report No. 2: 49.

USGS Twin Buttes Quadrangle topo map.

Arizona Bureau of Mines file data.

MRDS database Dep. ID file #10039577, MRDS ID #M050362; and, Dep. ID #10234484, MAS ID #0040190388.

A former small underground Zn-Pb-Ag-Cu-Au-Baryte-Gypsum mine located in the SW ¼ sec. 2, T.17S., R.12E., in the northern part of the Pima District, 22 road miles south of Tucson and 5 miles NNW of Twin Buttes. Owned at times, or in part, by the San Xavier Mining & Smelting Co.; Myers; Clark & Rowe Co.; Empire Zinc Co.; Eagle Picher Mining & Smelting Co.; and McFarland & Hullinger.

Mineralization is irregular, pyrometasomatic replacement ore deposits as pipes, lenses, and mantos with secondary minerals in the oxidized zone and sulfides at depth. The ores are largely controlled by fractures and fracture intersections forming breccia pipes as well as favorable beds in Paleozoic limestone below a fault contact with mixed Triassic and Cretaceous sediments and volcanics, within the San Xavier fault zone. Individual ore bodies are small and not continuous. Average width and length are given in size/directional data. Oxidation extends to irregular depths 100 - 200 feet, but can reach as deep as the 420 foot-level.

In 1880, Colonel P. Sykes purchased the San Xavier mine and organized the San Xavier Mining and Smelting Co. A small blast furnace was erected on the Santa Cruz River, 9 miles south of Tucson, to treat the ore, but it was unsuccessful. During 1897, L.H. Manning shipped ore from the San Xavier Mine. The Empire Zinc Co. purchased the San Xavier in 1912 and shipped Pb-Zn-Ag ore from it until 1918. In 1943 Eagle Picher Mining and Smelting Co. constructed a concentrator at Sahuarita with a daily capacity of 175 tons, and reopened the San Xavier Mine. Since 1943 the San Xavier mine has been one of the more important producers of Zn & Pb in Arizona, and for 1948 its output of these metals ranked third in the state.

The Permian series of limestone, quartzite, and marl-gypsum beds is overlain on the south by Cretaceous arkose and shale. In places, Pre-cretaceous erosion removed part of the Permian series.

The beds lie in a southward-lnging syncline. Their dip ranges from 20º to 90º, and averages about 55º, southward. Relatively small rolls of southward trend are apparent underground.

A steeply southward-dipping fault zone strikes about N.70ºE. at the mine but swings southeasterly on the east and southwesterly on the west. It is a complex zone with variable dip generally somewhat steeper than the bedding. Its hanging wall aparently moved relatively upward and possibly eastward, but the amount of displacement is unknown. Two principal faults, termed the 17 and 10, are found in this fault zone. The 10 fault, in the eastern part of the mine, is within the hanging wall of 17 fault and subparallel to it in strike but of steeper dip. Other breaks strike northeastward and dip steeply. Another strikes eastward and dips at low angles southward.

The principal deposits form "chimeys," more or less closely associated with the 17 and 10 faults. These "chimneys" plunge steeply with the dip of the beds or with intersections of the faults and beds. Less important replacements follow northeast fissures and extend outward along beds. High grade ore tends to lie immediately below the arose or shale and also beneath low-angle slips.

Oxidation extends to irregular depths, generally 100-200 feet and exceptionally to the 420 level.

As a rule the individual orebodies are small and not continuous for long distances. They average about 15 or 18 feet in width, and their level lengths range unpredictably. In plan, the four principal "shoots" occur within an arcuate sector approximately 500 feet long.

Workings include shaft operations to a depth of 152.4 meters. Worked as early as the 1700's for silver. Total estimated and reported intermittent production, mainly in 1913-1918 and 1943-1959, would be some 800,000 tons of ore averaging about 10% Zn, 6% Pb, 3 oz. Ag/T, 0.7% Cu and minor Au. Production as of 1949 was some 17,260,303 pounds of Zn, 9,637,071 pounds of Pb, 1,009,398 pounds of Cu, and 274,516 ounces Ag. In March, 1949 ore ad been produced from the 660 level, and development had extended to the 900 level. San Xavier is now part of the Mission Complex. See MRDS record MO50387.

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Link to USGS MRDS:	10039577

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