Porphyry copper deposit in Arizona, United States

Names and other identifiers

Alternate names Rosemont
Tract name Western Sierra Madre Occidental and Laramide Central (003pCu3007x)
Included sites Broadtop Butte, Copper World, Peach-Elgin, Helvetia, Rosemont
Site status deposit

Geographic location

Country United States
State or province Arizona
Geographic location -110.76, 31.83
Geologic map unit -110.76, 31.83
Nearby data

Geologic information

Deposit type Porphyry copper
Age (Ma) 59Ma
Age determination method unknown
Age range 56–62 Ma
Age reference Singer and others (2008)
Minerals azurite/malachite, bornite, chalcopyrite, chrysocolla, cuprite/tenorite, diopside, epidote, galena, garnet, gold, magnetite, molybdenite, sericite, pyrite, scheelite, sphalerite, wollastonite
Associated rocks quartz latite porphyry, quartz monzonite, skarn, andesite, chert, arkose, conglomerate, dolomite, granodiorite, limestone, quartzite, sandstone, shale, siltstone
Tectonic setting continental margin
Stratigraphic age Paleocene

Commodity and development information

Development status Occurrence
Major commodities Cu
Tonnage (Mt) 952Mt
Cu grade (%) 0.552%
Mo grade (%) 0.0055%
Au grade (g/t) 0.019g/t
Ag grade (g/t) 8.8g/t
Contained copper 5,260,000t
Gold-Moly ratio 3.5

Reference information

Comments Exposed.
Study area name United States
References Anzalone (1995); Long and others (1998); Niemuth (1994); Titley (1993); Titley and Anthony (1989); Singer and others (2008)
Site reference U.S. Geological Survey National Mineral Resource Assessment Team (2002)
Anzalone, S.A., 1995, The Helvetia area porphyry systems, Pima County, Arizona, in Pierce, F.W., and Bolm, J.G., eds., Porphyry copper deposits of the American Cordillera: Tucson, Arizona Geological Society Digest 20, p. 436–441.
Long, K.R., De Young, J.H., Jr., and Ludington, S.D., 1998, Database of significant deposits of gold, silver, copper, lead, and zinc in the United States—Part A, Database description and analysis; Part B, Digital database: U.S. Geological Survey Open-File Report 98-206, 33 p., one 3.5-inch diskette. (Also available at, N.J., 1994, The primary copper industry of Arizona, 1992: Arizona Department of Mines and Mineral Resources Special Report 20, 58 p. (Also available at, 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
Titley, S.R., 1993, Characteristics of porphyry copper occurrence in the American Southwest, in Kirkham, R.V., Sinclair, W.D., Thorpe, R.I., and Duke, J.M., eds., Mineral deposit modeling: Geological Association of Canada Special Paper 40, p. 433–464.
Titley, S.R., and Anthony, E.Y., 1989, Laramide mineral deposits in Arizona, in Jenney, J.P., and Reynolds, S.J., eds., Geologic evolution of Arizona: Tucson, Arizona Geological Society Digest 17, p. 485–514.