Silver Bell

Porphyry copper (Cu-Mo) deposit in Arizona, United States

Names and other identifiers

GMRAP ID 79
Tract name Western Sierra Madre Occidental and Laramide Central (003pCu3007x)
Included sites North Silver Bell
Site status deposit

Geographic location

Country United States
State or province Arizona
Geographic location -111.524878178, 32.403618415
Geologic map unit -111.524878178, 32.403618415
Nearby data

Geologic information

Deposit type Porphyry copper
Deposit subtype Cu-Mo
Age (Ma) 68Ma
Age determination method unknown
Age range 69–66 Ma
Age reference Singer and others (2008)
Minerals actinolite, alunite, azurite/malachite, barite, biotite, brochantite, chalcanthite, chalcocite, chalcopyrite, chlorite, chrysocolla, copper, cuprite, diopside, epidote, garnet, goethite/limonite, jarosite, melanterite, molybdenite, pyrite, sericite, tenorite, torbernite, wollastonite
Associated rocks andesite porphyry, intrusive breccia, monzonite porphyry, quartz latite porphyry, quartz monzonite porphyry, skarn, syenodiorite porphyry, alaskite, arkose, conglomerate, dacite porphyry, limestone, quartzite, siltstone
Tectonic setting continental margin
Stratigraphic age Late Cretaceous

Commodity and development information

Development status Producer
Major commodities Cu
Tonnage (Mt) 268Mt
Cu grade (%) 0.66%
Mo grade (%) 0.013%
Au grade (g/t) 0.026g/t
Ag grade (g/t) 0.96g/t
Contained copper 1,800,000t
Gold-Moly ratio 2

Reference information

Comments 10% covered.
Study area name United States
References Einaudi (1982); Graybeal (1982); Graybeal (1991); Kenyon and Courtright (1966); Long (1995); Lopez and Titley (1995); Sawyer (1994); Titley (1994); Singer and others (2008)
Site reference U.S. Geological Survey National Mineral Resource Assessment Team (2002)
Einaudi, M.T., 1982, Description of skarns associated with porphyry copper plutons, southwestern North America, in Titley, S.R., ed., Advances in geology of the porphyry copper deposits, southwestern North America: Tucson, University of Arizona Press, p. 139–183.
Graybeal, F.T., 1982, Geology of the El Tiro area, Silver Bell mining district, Pima County, Arizona, in Titley, S.R., ed., Advances in geology of the porphyry copper deposits, southwestern North America: Tucson, University of Arizona Press, p. 487–505.
Graybeal, F.T., 1991, History of exploration at Silver Bell, Arizona, in Hollister, V.F., ed., Case histories of mineral discoveries, v. 3: Littleton, Colorado, Society for Mining, Metallurgy, and Exploration, Inc., p. 45–47.
Kenyon, R., and Courtright, J.H., 1966, Structure and mineralization at Silver Bell, Arizona, in Titley, S.R., and Hicks, C.L., eds., Geology of the porphyry copper deposits, southwestern North America: Tucson, University of Arizona Press, p. 157–163.
Long, K.R., 1995, Production and reserves of Cordilleran (Alaska to Chile) porphyry copper deposits, in Pierce, F.W., and Bolm, J.G., eds., Porphyry copper deposits of the American Cordillera: Tucson, Arizona Geological Society Digest 20, p. 35–68.
Lopez, J.A., and Titley, S.R., 1995, Outcrop and capping characteristics of the supergene sulfide enrichment at North Silver Bell, in Pierce, F.W., and Bolm, J.G., eds., Porphyry copper deposits of the American Cordillera: Tucson, Arizona Geological Society Digest 20, p. 424–435.
Sawyer, D.A., 1994, Geologic map of a Late Cretaceous caldera and related porphyry copper-molybdenum ore deposits in the Silver Bell mining district, Arizona, and their subsequent Tertiary structural history, in Carter, L.M.H., Toth, M.I., and Day, W.C., eds., USGS research on mineral resources—1994, Part A—Program and abstracts: U.S. Geological Survey Circular 1103-A, p. 91–92. (Also available at http://pubs.usgs.gov/circ/1994/1103a/report.pdf.)Singer, D.A., Berger, V.I., and Moring, B.C., 2008, Porphyry copper deposits of the world—Database and grade and tonnage models, 2008: U.S. Geological Survey Open-File Report 2008-1155, [45] p. and digital data, accessed December 31, 2013, at http://pubs.usgs.gov/of/2008/1155/.Titley, S.R., 1994, Silver Bell porphyry copper deposit, Silver Bell Mountains, Pima County, Arizona, in Thorman and Lane, D.E., USGS research on mineral resources—1994, Part B—Guidebook for field trips: U.S. Geological Survey Circular 1103-B, p. 77–88. (Also available at http://pubs.usgs.gov/circ/1994/1103b/report.pdf.)