Lomas Bayas

Porphyry copper deposit in Antofagasta, Chile

Names and other identifiers

GMRAP ID 295
Tract name Chile-Peru Paleocene–Eocene Toquepala (005pCu1008)
Included sites Fortuna de Cobre
Site status deposit

Geographic location

Country Chile
State or province Antofagasta
Geographic location -69.511666667, -23.445
Geologic map unit -69.511666667, -23.445
Nearby data

Geologic information

Deposit type Porphyry copper
Age (Ma) 57.5Ma
Age determination method unknown
Age range 57.9–57.1 ±1.8 Ma
Age reference Singer and others (2008)
Minerals alunite, antlerite, atacamite, azurite/malachite, biotite, bornite, brochantite, chalcanthite, chalcocite, chalcopyrite, chlorite, chrysocolla, copiapite, copper, coquimbite, covellite, epidote, jarosite, melanterite, molybdenite, pyrite, sericite, sideronatrite, tennantite, tourmaline, voltaite
Associated rocks breccia, feldspar porphyry, granodiorite porphyry, tonalite porphyry,limestone, sandstone, shale,granodiorite
Tectonic setting continental margin
Stratigraphic age Paleocene

Commodity and development information

Development status Producer
Major commodities Cu
Tonnage (Mt) 1,230Mt
Cu grade (%) 0.279%
Contained copper 3,430,000t
Gold-Moly ratio -9999

Reference information

Comments Cu enrichment age 21 Ma. 40% of the deposit area covered by alluvium and colluvium.
Study area name Andes
References Boric and others (1990); Chadwick (2001); Chavez (1998); SEG Newsletter (1999); Palacios and others (2007); Shrake and others (1996); Sillitoe and McKee (1996); Sillitoe and Perelló (2005); Singer and others (2008)
Site reference Cunningham and others (2008)
Boric, R.P., Diaz, F.F., and Maksaev, V.J., 1990, Geología y yacimientos metalíferos de la Región de Antofagasta: Santiago, [Chile] Servicio Nacional de Geología y Mineneria, Boletin 40, 246 p., 1 map, scale 1:500,000.
Chadwick, J., 2001, Andean action: Mining Magazine, v. 184, no. 5, p. 234–247.
Chávez, W.X., Jr., 1998, Exploration review—Chile: Society of Economic Geologists SEG Newsletter, no. 35, p. 24–26. (Also available at http://www.segweb.org/pdf/publications/newsletters/1998/SEG-Newsletter-35-1998-October.pdf.)Palacios, C., Ramírez, L.E., Townley, B., Solari, M., and Guerra, N., 2007, The role of the Antofagasta–Calama lineament in ore deposit deformation in the Andes of northern Chile: Mineralium Deposita, v. 42, p. 301–308. (Also available at http://dx.doi.org/10.1007/s00126-006-0113-3.)SEG Newsletter, 1999, SEG Student Chapter News—New Mexico Tech—Ore deposits of northern Chile: Society of Economic Geologists SEG Newsletter, no. 37, p. 19–20. (Also available at http://www.segweb.org/pdf/publications/newsletters/1999/SEG-Newsletter-37-1999-April.pdf.)Shrake, T.C., Ernst, D.R., Thurston, P., and Ashleman, J., 1996, Geology of Chile’s Lomas Bayas porphyry copper deposit: Mining Engineering, v. 48, no. 3, p. 37–42. (Abstract also available at http://www.onemine.org/search/summary.cfm/Geology-of-Chiles-Lomas-Bayas-Porphyry-Copper-Deposit?d=72319BEECD0D27AA7AB510CD93497CF36E3BBC9C38C36BC36E3B979CCA2F1FBA34110.)Sillitoe, R.H., and McKee, E.H., 1996, Age of supergene oxidation and enrichment in the Chilean porphyry copper province: Economic Geology, v. 91, p. 164–179. (Also available at http://dx.doi.org/10.2113/gsecongeo.91.1.164.)
Sillitoe, R.H., and Perelló, Jose, 2005, Andean copper province—Tectonomagmatic settings, deposit types, metallogeny, exploration, and discovery, in Hedenquist, J.W., Thompson, J.F.H., Goldfarb, R.J., and Richards, J.P., eds., Economic Geology One Hundredth Anniversary Volume, 1905–2005: Littleton, Colo., Society of Economic Geologists, p. 845–890.
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/.