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Esperanza Mine [new] (Esperanza pit; Esperanza open pit mines; West Esperanza Mine), Pima District (Olive District; Mineral Hill District; Twin Buttes District), Sierrita Mts, Pima Co., Arizona, USA

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Latitude & Longitude (WGS84): 31° 52' 4'' North , 111° 7' 44'' West
Latitude & Longitude (decimal): 31.86778,-111.12889
Other regions containing this locality:Sonoran Desert, North America
Köppen climate type:BSk : Cold semi-arid (steppe) climate

A former large Cu-Mo-Ag-Au-Pb-Zn (U) occurrence/mine located in the SE¼ sec. 8, the NW¼ sec. 16 & the NE¼ sec. 17, T18S, R12E. (Batamote Hills 7.5 minute topo map), 4½ miles SW of Twin Buttes and 48 km S of Tucson on private property. Discovered by P.H. Chambers in 1895. Produced 1959-1986. Owned at times, or in part, by the Duval Sulphur & Potash Co.; and the Duval Corp. (a Pennzoil subsidiary). Closed December, 1981.

Mineralization is an ovate, massive ore body comprised of disseminated copper sulfides, oxides, and carbonates with molybdenite and minor lead and zinc minerals, and traces of torbernite in brecciated, fissured, and jointed, strongly altered Laramide intrusive complex of quartz latite to andesite invading Triassic to Cretaceous volcanics. Ore control was faults which controlled the upward movement of hypogene and downward movement of supergene metallization. Ore concentration was supergene enrichment. Metallization occurred during several intrusive pulses and alteration. Alteration included clay (moderate to intense), quartz-sericite-K feldspar argillation, silicification, and biotite. An associated rock unit is the Ruby Star Quartz Monzonite Porphyry and the Ox Frame Volcanics. The ore body is 1,280.16 meters long, 701.04 meters wide, depth to top of 30.48 meters, depth to bottom 158.5 meters and 128.02 meters thick.

Local structures include a broad NW-trending shear zone. Faults trending NE-ENE, and dipping NW and SE; NW-NNW, dipping NE and SW; N-S, and dipping E and W.

Workings were open pit operations at 1,280 meters long by 609.6 meters wide. From 1959 through 1972, some 59,000,000 tons of ore averaging about 0.5% Cu, 0.017% Mo, 0.04 oz. Ag/T and minor Au, Zn, & Pb have been produced. Ore grade has averaged 0.5% Cu and 0.028% Mo since the start of operation.

Commodity List

This is a list of exploitable or exploited mineral commodities recorded at this locality.

Mineral List

40 valid minerals.

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org

Tithonian - Bajocian
145 - 170.3 Ma

ID: 2847718
Jurassic sedimentary and volcanic rocks

Age: Jurassic (145 - 170.3 Ma)

Stratigraphic Name: Gardner Canyon Formation; Rudolfo Redbeds; Recreation Red Beds; Topawa Group; Harquar Formation

Description: Sandstone and conglomerate derived from volcanic rocks with associated intermediate-composition lava flows, breccias, and tuffs. In southern Arizona this unit includes rocks of the Artesa sequence, Pitoikam Formation, Mulberry Wash volcanics, Rudolfo Red Beds, Recreation Red Beds, and Gardner Canyon Formation. In western Arizona it includes the Harquar Formation, rocks of Slumgullion, and related(?) unnamed units in the Kofa and Middle Mountains. This unit is characterized by maroon, brown, and purplish-gray volcanic-lithic sandstone and siltstone, with subordinate to abundant conglomerate, quartz-rich sandstone and sparse limestone. (150-170 Ma)

Lithology: Major:{sandstone,siltstone,conglomerate}, Minor:{felsic volcanic,limestone}

Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. [133]

Data and map coding provided by Macrostrat.org, used under Creative Commons Attribution 4.0 License

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The Resources of Arizona - A Manual of Reliable Information Concerning the Territory, compiled by Patrick Hamilton (1881), Scottsdale, AZ: 47.
Anderson, C.A., and Kupfer, D.H. (1945) Report on the properties of the Amargosa Molybdenum and Copper Corporation, Pima County, Arizona: U.S. Geological Survey Open-File Report [unnumbered], 20 p., 8 sheets.
U.S. Department of the Interior War Mineral Report. No. 405 (1945) Esperanza Property, Pima County, Arizona.
Tainter, S.L. (1947b), Amargosa (Esperanza) molybdenum-copper property, Pima County, Arizona, U.S. Bureau of Mines Report of Investigation 4016.
Schmidt, H.A., et al (1959), Disseminated deposits at the Esperanza copper mine, in Southern Arizona Guidebook II, Arizona Geological Society Digest: 2: 205.
Kirkemo, H., Anderson, C.A., and Creasey, S.C. (1965), Investigations of Molybdenum Deposits in the Conterminous United States 1942-60, Contributions to Economic Geology, USGS Bull. 1182-E: E12-E13.
Lynch, D.W. (1966), The economic geology of the Esperanza mine and vicinity, in S.R. Titley and C.L. Hicks (editors), Geology of the porphyry copper deposits, southwestern North America, University of Arizona Press, Tucson: 267-279.
Engineering and Mining Journal (1970) Duval Dedicates the Sierrita Open pit: July, 1970.
Engineering and Mining Journal (1970) Sierrita Makes it with Big Equipment: August, 1970.
Keith, Stanton B. (1974), Arizona Bureau of Geology & Mineral Technology, Geological Survey Branch Bull. 189, Index of Mining Properties in Pima County, Arizona: 135 (Table 4).
Aiken, D.M., and West, R.J. (1978) Some geologic aspects of the Sierrita-Esperanza copper-molybdenum deposit, Pima County, Arizona, in Jenney, J.P., and Hauck, H.R., eds., Proceedings of the Porphyry Copper Symposium, Tucson, Arizona, March 18-20, 1976: Arizona Geological Society Digest: 11: 117-128.
Mining Annual Review (1985): 55, 94 & 329.
Niemuth, N.J. & K.A. Phillips (1992), Copper Oxide Resources, Arizona Department of Mines & Mineral Resources Open File Report 92-10: 12 (Table 1).
Sawyer, M.B., Gurmendi, A.C., Daley, M.R., and Howell, S.B. (1992) Principal Deposits of Strategic and Critical Minerals in Arizona, U.S. Bureau of Mines Special Publication, 334 pp.
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd. ed.: 107, 114, 163, 166, 220, 278, 312, 383, 405.
Singer, D.A., Berger, V.I., and Moring, B.C. (2008): Porphyry copper deposits of the world: Database and grade and tonnage models, 2008. US Geological Survey Open-File Report 2008-1155.
Arizona Bureau of Mines file data.
MRDS database Dep. ID file #10039594, MRDS ID #M050391; and, Dep. ID #10186590, MAS ID #0040190003.

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