The Mitsubishi Process for smelting stage and ISA Process for refinery were selected for the main processes that were used in Gresik Copper Smelter and Refinery, and also continuous casting system is used at anode casting stage.

The Lurgi-Mitsubishi double contact and double absorption is installed to treat Smelter off-gas. Multistage water treatment plant is also constructed in order to treat all effluents from the plant.  The general flow sheet of the process at Gresik Smelter and Refinery is shown in PT Smelting Simplified Diagram.