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Batu Hijau |
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Sumbawa, Indonesia |
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Cu Au
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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All papers now Open Access.
Available as Full Text for direct download or on request. |
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The Batu Hijau porphyry copper-gold deposit is located on the south-western corner of the island of Sumbawa in central Indonesia. Following sale of the controlling interests held by Newmont and Sumitomo in late 2016, the deposit is controlled by PT Amman Mineral Nusa Tenggara.
(#Location: 8° 57' 57"S, 116° 52' 22"E).
The deposit lies within the east-west trending Sunda-Banda magmatic arc at the convergent intersection of the Australian-Indian and the Eurasian plates. The northern half of Sumbawa is occupied by recent volcanoes, while the southern segment, where Batu Hijau is located, comprises oceanic crust overlain by low K calc-alkaline to weakly alkaline andesitic volcanics and volcaniclastics, associated intermediate intrusives and minor shallow marine sediments and limestones. In the mine area the sequence is represented by andesitic volcanic lithic breccias, volcaniclastic sandstones and mudstones and hypabyssal porphyritic andesites, with a younger thick sequence of quartz diorite in the east. Multiple tonalite porphyry intrusions were emplaced along the contact between the andesitic volcaniclastics and the quartz diorite. These tonalites, around which the mineralisation is zoned, are divided into the Old, Intermediate and Young Tonalites. Each has associated quartz veining and Cu-Au mineralisation, with the Old Tonalite having the highest grades and most intense associated alteration. The two following phases have progressively lower grades, vein densities and alteration.
SHRIMP 206Pb/238U geochronology indicates four major felsic intrusive episodes within the deposit area, each separated by 0.6 to 0.9 m.y. and related to a distinct porphyry centre with ages that range from 5.9 to 3.7 Ma. The duration of the Batu Hijau hydrothermal system is indicated by the 40Ar/39Ar closure of early biotite and late sericite of 3.73 ±0.08 Ma and 3.65 ±0.02 Ma respectively. The syn-mineral tonalite intrusions at Batu Hijau are interpreted to have been emplaced at a depth of <2 km (±0.5 km) whilst hornblende phenocrysts formed in magma chambers that reached at least 9 km below the mid-Pliocene palaeosurface, as indicated by the results of amphibole-plagioclase thermobarometry (Garwin, 2002).
Alteration and mineralisation has been divided into five temporally and spatially overlapping stages, namely:
i). Early pervasive biotite, secondary magnetite and plagioclase with fine 'A' type stockwork veining and bornite-digenite-chalcocite mineralisation,
ii). Transitional oligoclase/albite-sericite-quartz±vermiculite with planar 'B' veins containing chalcopyrite±bornite (representing 50 to 70% of the Cu in the deposit) and rare 'C' veining,
iii). Late feldspar destructive sericitic + other minerals (propylitic) alteration with associated 'D' veins of pyrite and quartz±chalcopyrite,
iv). Very Late feldspar destructive alteration producing smectite and chlorite with associated sphalerite, galena, tennantite, pyrite and chalcopyrite,
v). Zeolite alteration, a low temperature phase of open space filling, The final influence was oxidation to depths of 210 m with weak supergene sooty chalcocite enrichment in a thin 15 to 60 m thick layer.
Based on the feasibility study prior to the commencement of production in 2000, the Batu Hijau deposit had a resource of 1.1 Gt @ 0.525% Cu, 0.37 g/t Au. (Newmont website)
Proven+probable reserves at the end of 2003 were stated as 570 Mt @ 0.55% Cu, 0.37 g/t Au, representing 2.9 Mt of Cu and 215 tonnes of Au.
Ore reserves and mineral resources at 31 December 2015 for Newmont's 48.5% share were (Newmont, 2016):
Proved + probable reserve open pit ore - 200.60 Mt @ 0.44 g/t Au, 0.47% Cu
Proved + probable reserve stockpiles - 143.20 Mt @ 0.10 g/t Au, 0.33% Cu,
TOTAL proved + probable reserve - 243.80 Mt @ 0.42 g/t Au, 0.41% Cu,
with an average metallurgical recovery of ~73%.
Measured + indicated resource - 168.90 Mt @ 0.30 g/t Au, 0.36% Cu,
Inferred resource - 15.1 Mt @ 0.09 g/t Au, 0.30% Cu,
TOTAL resources - 184 Mt @ 0.28 g/t Au, 0.36% Cu,
Note: Resources are exclusive of reserves
Ore reserves + mineral resources, Newmont's 48.5% share - 427.8 Mt @ 0.36 g/t Au, 0.39% Cu,
Ore reserves + mineral resources, total deposit - 882.06 Mt @ 0.36 g/t Au, 0.39% Cu,
The most recent source geological information used to prepare this decription was dated: 2001.
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
Batu Hijau
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Arif J and Baker T 2004 - Gold paragenesis and chemistry at Batu Hijau, Indoneisa: implications for gold-rich porphyry copper deposits: in Mineralium Deposita v39 523-535
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Clode C, Proffett J, Mitchell P, Munajat I 1999 - Relationships of intrusion, wall-rock alteration and mineralisation in the Batu Hijau copper-gold porphyry deposit: in Proc. Pacrim 99 Conference, Bali, Indonesia, AusIMM, Melbourne pp 485-498
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Cooke, D.R., Agnew, P., Hollings, P., Baker, M., Chang, Z., Wilkinson, J.J., White, N.C., Zhang, L., Thompson, J., Gemmell, J.B., Fox, N., Chen, H. and Wilkinson, C.C., 2017 - Porphyry Indicator Minerals (PIMS) and Porphyry Vectoring and Fertility Tools (PVFTS) - Indicators of Mineralization Styles and Recorders of Hypogene Geochemical Dispersion Halos: in Tschirhart, V. and Thomas, M.D., (Eds.), 2017 Exploration 17: Sixth Decennial International Conference on Mineral Exploration, Toronto, Canada, October 22 to 25, 2017, Proceedings, Geochemistry, Paper 32, pp. 457-470.
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Garwin S 2002 - The geological setting of intrusion-related hydrothermal systems near the Batu Hijau porphyry copper-gold deposit, Sumbawa, Indonesia: in Goldfarb, Richard J. and Nielsen, Richard L. (Ed.s) 2002 Integrated Methods for Discovery: Global Exploration in the 21st Century Soc. of Econ. Geologists, Denver Spec. Publ. 9 pp 333-366
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Irianto B, Clarke D S 1995 - The Batu Hijau porphyry copper-gold deposit, Sumbawa Island, Indonesia: in Proc of 1995 Pacrim Congress, Aukland, NZ AusIMM, Melbourne pp 299-304
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Maryono, A., Harrison, R.L., Cooke, D.R., Rompo, I. and Hoschke, T.G., 2018 - Tectonics and Geology of Porphyry Cu-Au Deposits along the Eastern Sunda Magmatic Arc, Indonesia: in Econ. Geol. v.113, pp. 7-38.
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Maula, S. and Levet, B., 1996 - Porphyry copper gold signatures and the discovery of the Batu Hijau deposit, Sumbawa, Indonesia: in Porphyry Related Copper and Gold Deposits of the Asia Pacific Region, Conf Proc, Cairns, 12-13 Aug, 1996 AMF, Adelaide pp 8.1-8.13.
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McInnes B I A, Evans N J, Fu F Q, Garwin S, Belousova E, Griffin W L, Bertens A, Sukarna D, Permanadewi S, Andrew R L and Deckart K, 2005 - Thermal History Analysis of Selected Chilean, Indonesian and Iranian Porphyry Cu-Mo-Au Deposits: in Porter T M (Ed), 2005 Super Porphyry Copper & Gold Deposits - A Global Perspective, PGC Publishing, Adelaide, v.1 pp. 27-42
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Meldrum S J, Aquino R S, Gonzales R I, Burke R J, Suyadi A, Irianto B, Clarke D S 1994 - The Batu Hijau porphyry copper-gold deposit, Sumbawa Island, Indonesia: in J. of Geochemical Exploration v50 pp 203-220
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Neal, L.C., Wilkinson, J.J., Mason, P.J. and Chang, Z., 2018 - Spectral characteristics of propylitic alteration minerals as a vectoring tool for porphyry copper deposits: in J. of Geochemical Exploration v.184, pp. 179-198.
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Schirra, M., Laurent, O., Zwyer, T., Driesner, T. and Heinrich, C.A., 2022 - Fluid Evolution at the Batu Hijau Porphyry Cu-Au Deposit, Indonesia: Hypogene Sulfide Precipitation from a Single-Phase Aqueous Magmatic Fluid During Chlorite - White-Mica Alteration: in Econ. Geol. v.117, pp. 979-1012.
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Wilkinson, J.J., Chang, Z., Cooke, D.R., Baker, M.J., Wilkinson, C.C., Inglis, S., Chen, H. and Gemmell, J.B., 2015 - The chlorite proximitor: A new tool for detecting porphyry ore deposits: in J. of Geochemical Exploration v.152, pp. 10-26.
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Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
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