Porphyry copper (Cu-Au) deposit in Papua, Indonesia

Names and other identifiers

Tract name Western Medial New Guinea Magmatic Belt (142pCu7203)
Group name Grasberg
Included sites Ertsberg, Gunung Bijih, Kusing Liar
Site status deposit

Geographic location

Country Indonesia
State or province Papua
Geographic location 137.1144, -4.0461
Geologic map unit 137.1144, -4.0461
Nearby data

Geologic information

Deposit type Porphyry copper
Deposit subtype Cu-Au
Age determination method Geologic inference
Age range Pliocene
Age reference McDowell and others (1996); Paterson and Cloos (2005a); Paterson and Cloos (2005b)
Minerals actinolite, andalusite, anhydrite/gypsum, biotite, bornite, chalcocite/digenite, chalcopyrite, chlorite, colusite, covellite, diopside, enargite, epidote, galena, garnet, gold, hematite, kaolinite/illite, magnetite, marcasite, molybdenite, montmorillonite/smectite, muscovite/sericite, nukundamite, pyrite, serpentine, sphalerite, sulfur, valleriite, wollastonite
Associated rocks andesite breccia, breccia, diorite, diorite porphyry, marble, monzodiorite porphyry, monzonite porphyry, skarn, black shale, dolomite, limestone, quartzite, sandstone, siltstone
Tectonic setting postconvergence
Stratigraphic age Pliocene

Commodity and development information

Development status Producer
Major commodities Cu, Au
Minor commodities Pt, Pd
Tonnage (Mt) 4,000Mt
Cu grade (%) 0.6%
Au grade (g/t) 0.64g/t
Ag grade (g/t) 2g/t
Contained copper 24,000,000t
Gold-Moly ratio -9999

Reference information

Comments Exposed. In ore: 0.0007 g/t Pt, 0.003 g/t Pd; in concentrate: 0.015 g/t Pt, 0.058 g/t Pd. Freeport established in 2003 reserve of Deep MLZ target at the Grasberg cluster: 159 Mt at 0.87% Cu and 0.76 g/t Au.
Study area name Southeast Asia and Melanesia
References Anonymous (2004); Cloos (1997); Cloos and Housh (2008); Economou-Eliopoulos and others (2001); Freeport-McMoRan Copper and Gold Inc. (1999, 2006, 2009, 2010); MacDonald and Arnold (1994); MacDonald and Arnold (1995); McDowell and others (1996); Meinert and others (1997); Mertig and others (1994); Paterson and Cloos (2005a); Paterson and Cloos (2005b); Pollard and Taylor (2002); Potter (1996); Singer and others (2008)
Site reference Hammarstrom and others (2013)
Anonymous, 2004, Freeport drills more copper and gold at Grasberg: Mining Journal, v. May 7, p. 9.
Cloos, Mark, 1997, Anatomy of a mine—The discovery and development of Grasberg: Geotimes, v. 42, no. 1, p. 16–20.
Cloos, Mark, and Housh, T.B., 2008, Collisional delamination—Implications for porphyry-type Cu-Au ore formation, in Spencer, J.E., and Titley, S.T., eds. Ores and Orogenesis—Circum-Pacific tectonics, geologic evolution, and ore deposits: Arizona Geological Society Digest 22, p. 235–244.
Economou-Eliopoulos, M., Eliopoulos, D.G., and Perantonis, G., 2001, Factors controlling the Pd and Pt potential of the Skouries porphyry-Cu deposit, Chalkidiki, N. Greece, in Piestrzy?ski, Adam, and others, eds., Mineral deposits at the beginning of the 21st century: Lisse, The Netherlands, A.A. Balkema Publishers, Society for Geology Applied to Mineral Deposits (SGA) Biennial Meeting, 6th, Krakow, Poland, August 26–29, 2001 [Proceedings], p. 731–734.
Freeport-McMoRan Copper and Gold, Inc., 1999, Freeport-McMoRan Copper and Gold updates exploration activities: Freeport-McMoRan Copper and Gold, Inc. press release, May 18, 1999, accessed May 20, 2010, at Copper and Gold, Inc., 2006, Annual report to the U.S. Securities and Exchange Commission Form 10-K for the fiscal year ending December 31, 2006: accessed March 10, 2011, at downloads/FCX200610K.pdf.Freeport-McMoRan Copper and Gold Inc., 2009, Grasberg: Freeport-McMoRan Copper and Gold Inc. Web page, accessed March 15, 2010, at Copper and Gold, Inc., 2010, Freeport McMoRan Copper and Gold Inc. reports fourth-quarter and year ended December 31, 2010 results: accessed March 1, 2011, at, G.D., and Arnold, L.C., 1994, Geological and geochemical zoning of the Grasberg igneous complex, Irian Jaya, Indonesia: Journal of Geochemical Exploration, v. 50, p. 143–178.
MacDonald, G.D., and Arnold, L.C., 1995, Factors responsible for extreme concentration of Cu and Au in the Grasberg deposit—A comparative look at the porphyry copper systems of the Ertsberg district, Indonesia, in Clark, A.L., ed., Giant ore deposits–II: Kingston, Ontario, Queens University, p. 314–333.
McDowell, F.W., McMahon, T.P., Warren, P.Q., and Cloos, Mark, 1996, Pliocene Cu-Au bearing igneous intrusions of the Gunung Bijih (Ertsberg) district, Irian Jaya, Indonesia—K-Ar geochronology: Journal of Geology, v. 104, p. 327–340. (Abstract also available at, L.D., Hefton, K.K., Mayes, D., and Tasiran, Ian, 1997, Geology, zonation, and fluid evolution of the Big Gossan Cu-Au skarn deposit, Ertsberg district, Irian Jaya: Economic Geology, v. 92, p. 509–534. (Also available at, H.J., Rubin, J.N., and Kyle, J.R., 1994, Skarn Cu-Au orebodies of the Gunung Bijih (Ertsberg) district, Irian Jaya, Indonesia: Journal of Geochemical Exploration, v. 50, p. 179–202. (Also available at, J.T., and Cloos, M., 2005a, Grasberg porphyry Cu-Au deposit, Papua, Indonesia—1. Magmatic history, in Porter, T.M., ed., Super porphyry copper and gold deposits—A global perspective: Adelaide, PGC Publishing, v. 2, p. 313–329. (Abstract also available at, J.T., and Cloos, M., 2005b, Grasberg porphyry Cu-Au deposit, Papua, Indonesia—2. Pervasive hydrothermal alteration, in Porter, T.M., ed., Super porphyry copper and gold deposits—A global perspective: Adelaide, PGC Publishing, v. 2, p. 331–355. (Abstract also available at, P.J., and Taylor, R.G., 2002, Paragenesis of the Grasberg Cu–Au deposit, Irian Jaya, Indonesia—Results from logging section 13: Mineralium Deposita, v. 37, p. 117–136. (Also available at
Potter, D., 1996, What makes the Grasberg anomalous, implications for future exploration, in Porphyry related copper and gold deposits of the Asia Pacific region: Conference Proceedings, Australian Mineral Foundation, Glenside, South Australia, p. 10.1–10.13.
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