All economic mineralisation at Gosowong is of low sulphidation epithermal type occurring as mineralised fault systems resulting from high temperature gold and silver bearing hydrothermal fluids. The ore shoots are narrow and approximately planar although irregular and complex in local detail. The deposits are relatively moderate to low in dip averaging around 40-50 degrees in the Kencana – Gosowong structural corridor and sub-vertical in the Toguraci corridor. Silver to gold ratio in the ore is approximately 1:1.

The Toguraci low sulphidation epithermal gold vein deposits are located 2 km south west of the Gosowong mine and form part of the Gosowong Goldfield. The vein structures at Toguraci are narrow with horizontal widths typically ranging between 0.1m and 5m.

The Kencana underground mine utilises predominantly underhand cut-and-fill with some long hole stoping while the Toguraci underground mine uses long hole stoping and overhand cut-and fill.

Open pit mining at Toguraci commenced in October 2003, with the mining of the Damar vein and then subsequently extending to the T-Fault, Midas, and Jembatan veins and later to the Damar and Kayu Manis veins. Open pit mining at Toguraci concluded in October 2006 with underground mining commencing in 2011.

The processing plant at Gosowong, which has a capacity of up to 800,000 tonnes per year, comprises a primary jaw crusher followed by a SAG and ball mill circuit and a Vertimill circuit. The ore then undergoes a conventional cyanide leaching process. Gold and silver is recovered from the cyanide solution using the Merrill-Crowe zinc precipitation process and smelted to produce gold and silver doré. The gold doré is then refined at Logam Mulia which is owned by Newcrest’s joint venture partner PT Aneka Tambang.