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).
In Grasberg Block Cave (GBC) Mine area, anhydrite-gypsum and sulfur mineral distribution can be traced in Grasberg Intrusive Complex (GIC), skarn, and Heavy Sulphide Zone (HSZ).
GIC and Skarn contain abundant of anhydritegypsum as product of alteration. Potassic alteration in GIC are characterized by anhydrite appearance within the rock or as intense stockwork veins associate with quartz-pyritechalcopyrite. In the skarn, anhydrite mineral appear as dominant alteration mineral especially if the skarn occurred between contact of igneous rock and Warip ........
