Cuatro Hermanos

Porphyry copper deposit in Sonora, Mexico

Names and other identifiers

Tract name Western Sierra Madre Occidental and Laramide Central (003pCu3007x)
Site status deposit

Geographic location

Country Mexico
State or province Sonora
Geographic location -109.644997236, 28.388016681
Geologic map unit -109.644997236, 28.388016681
Nearby data

Geologic information

Deposit type Porphyry copper
Age (Ma) 55.7Ma
Age determination method Re-Os molybdenite
Age range 55.7 ±0.3 Ma
Age reference Barra and others (2005)
Minerals biotite, chalcocite, chalcopyrite, gold, goethite, hematite, jarosite, malachite, molybdenite, pyrite, sericite, tourmaline
Associated rocks granite, monzodiorite, quartz monzonite
Tectonic setting continental margin
Stratigraphic age Paleocene–Eocene

Commodity and development information

Development status Past Producer
Tonnage (Mt) 764Mt
Cu grade (%) 0.18%
Mo grade (%) 0.02%
Ag grade (g/t) 1.208g/t
Contained copper 1,400,000t
Gold-Moly ratio -9999

Reference information

Comments Updated total resource weighted avg. to 763,772,000 t at 0.181% Cu, 0.022% Mo, 1.208 g/t Ag. Indicated resources: 206,262,000 t at 0.197% Cu, 0.021%Mo. Inferred resources: 557,510,000 t at 0.174% Cu, 0.022% Mo. Breccia, dacite porphyry, tonalite porphyry. Location: prospect location on 250K; within mapped alteration. Advanced exploration property with several targets - porphyry copper and exotic copper in conglomerate (Virgin Metals, Inc.). Drilled: 1969 (Occidental), 1974-75 (Amoco), 1981 (Cominco), 1993-2004 with mapping, mag, and EM (Morgain Minerals), 1997 (BHP), plus geochem sampling by other companies. Biotite quartz-diorite intrusive (3 km long by 1 to 2 km wide); mineralized breccia pipes. Alteration: oxidation-argillization.
Study area name Mexico
References Barton and others (1995); Fitch (1993); Sillitoe (1976); García-Cortez and others (2000); Priesmeyer and Leroux (2006); Singer and others (2005); Barnard and Sandefur (2008); Fitch (2000); Singer and others (2008); Barra and others (2005)
Site reference Hammarstrom and others (2010)
Barnard, Fred, and Sandefur, Robert, 2008, Technical report, Los Verdes project, Sonora, Mexico: Lakewood, Colo., Chlumsky, Armbrust and Meyer LLC National Instrument 43-101 Technical Report prepared for Virgin Metals Inc., 99 p. (Also available at, Fernando; Ruiz, Joaquin; Valencia, V.A.; Ochoa-Landín, Lucas; Chesley, J.T., and Zürcher, Lukas, 2005, Laramide porphyry Cu-Mo mineralization in northern Mexico—Age constraints from Re-Os geochronology in molybdenite: Economic Geology, v. 100, p. 1605–1616. (Also available at
Barton, M.D., Staude, J.-M.G., Zürcher, L., and Megaw, P.K.M., 1995, Porphyry copper and other intrusion-related mineralization in Mexico, in Pierce, F.W., and Bolm, J.G., eds., Porphyry copper deposits of the American Cordillera: Tucson, Arizona Geological Society Digest, v.20, p.487–524.
Fitch, D.C., 1993, Mexico active metals exploration and mining properties report: Littleton, Colo., Mining Business Digest.
Fitch, D.C., 2000, Mexico mineral occurrences, map and GIS database (3,722 selected mineral occurrences from Consejo de Recursos Minerales Monograph data with USGS selected data): Reno, Nev., David C. Fitch, CD-ROM. (Commercial data available from David C. Fitch, Consulting Geologist, P.O. Box 70547, Reno, NV 89570, USA or at
García-Cortez, J.A., Guzmán-Espinoza, J.B., Mancillas-Gutiérrez, A.A., García-Duarte, Rodolfo, and Siqueiros-López, Christian, 2000, Carta geológico-minera, Tecoripa H12-12, Sonora and Chihuahua [Mexico]: Pachuca, Hidalgo, Servicio Geológico Mexicano, 1 sheet, scale 1:250,000.
Priesmeyer, S.T., and Leroux, D.C., 2006, Technical report on the Cuatro Hermanos copper-molybdenum project, Sonora State (for Virgin Metals, Inc.): A.C.A. Howe International Ltd. Report #894.
Sillitoe, R.H., 1976, A reconnaissance of the Mexican porphyry copper belt: Institutions of Mining and Metallurgy Transactions, Section B—Applied Earth Science, v. 85, p. B170–B189.
Singer, D.A., Berger, V.I., and Moring, B.C., 2005, Porphyry copper deposits of the world—Database, map, and grade and tonnage models: U.S. Geological Survey Open-file Report 2005-1060, [9] p. and digital data, accessed December 31, 2013, 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