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The Ertsberg mining district is a 100 km2 area in the highlands of Papua, Indonesia. The district hosts mineralised and barren, outcropping and hidden porphyry and equigranular intrusions. There are at least six major (100+ m wide) porphyry intrusions identified from surface and underground mapping and drill cores. These are the Grasberg Igneous Complex (GIC), Karume porphyry, Lembah Tembaga porphyry, Ertsberg Stockwork Zone porphyry, Kay intrusion and the Wanagon intrusion. Recent deep drilling adjacent to the GIC identified a new hidden porphyry at depth, the Gajah Tidur (Sleeping Elephant), which extends south-west beneath the Kucing Liar skarn. Other named small porphyry dykes and plugs in the district include the West Grasberg, North Grasberg, Idenberg, South East and Zaagkam intrusions. The largest equigranular intrusion is the multiphase Ertsberg diorite.Igneous activities occurred in a relatively short span (<1 million years) from about 3.4 ma to 2.7 ma ago, based on u-pb zircon dating. the various intrusions in the district related to ore mineralisation are high k and appear to have been derived from the same parental chamber, based on similar whole rock rare earth element patterns. radiogenic nd- and sr-isotopic variations indicate that there were multiple recharge events into the parental chamber.the larger intrusions and all economic mineralisation occur in a 4 km wide zone that parallels the n60w-trending axis of the yellow valley syncline (yvs), one of the large folds generated during collisional tectonism. intrusion pathways at ~3 ma were localised into dilatational areas in a late and or post-collisional nw-trending, left-lateral strike-slip zone with riedel shear offsets between the major fault zones. an early phase of lower k magmatism produced small intrusions in the south-west limb of the yvs.citation:de jong, g, sunyoto, w and cloos, m, 2015. composition, lithochemistry and radiogenic isotopes of porphyritic and equigranular intrusions in the ertsberg mining district, papua, indonesia, in proceedings pacrim 2015 congress, pp 347-356 (the australasian institute of mining and metallurgy: melbourne).>