The Grasberg minerals district is situated on the crest of the Sudirman Mountain Range at elevations over 2,500 meters with the highest peak, Puncak Jaya at 4,884 meters. Ore deposits in the Grasberg minerals district have economic copper, gold, and silver mineralization in porphyries and skarns. The primary sulfide mineralization is chalcopyrite, with lesser bornite, chalcocite, and covellite. Gold concentrations usually occur as inclusions within the copper sulfide minerals although in some parts of deposits gold can also be strongly associated with pyrite.
There are five major ore bodies all within the center of the Grasberg minerals district:
• Grasberg Intrusive Complex (GIC) includes the GBC and the depleted GRS_OP.
• EESS includes DMLZ and depleted GBT, IOZ, DOZ block caves.
• BG.
• KL (development stage mineral reserve).
• Dom (classified as mineral resource).
The DMLZ ore body lies below the Deep Ore Zone (DOZ) underground mine at the 2,590-meter elevation and represents the downward continuation of mineralization in the Ertsberg East Skarn system and neighboring Ertsberg porphyry.
The igneous-hosted ore bodies (the Grasberg Block Cave and portions of the DMLZ) occur as vein stockworks and disseminations of copper sulfides, dominated by chalcopyrite and, to a lesser extent, bornite. The sedimentary-rock hosted ore bodies (portions of the DMLZ and Kucing Liar and all of the Big Gossan) occur as “magnetite- ........