The lateritic nickel deposits in Sorowako, formed through the corrosion of ultramaphic stone, are spread out in the largest single exposure – an area of more than 120 km x 60 km – in the world. There are also a number of other deposits in Central and Southeast Sulawesi.

Pt Inco's nickel mining operation in Sorowako is classified as open pit/cast mining involving the following steps:

Drilling
at a spacing of 25-50 meters in order to take samples of rocks and soil in order to determine the amount of nickel to be found in the area.

Clearing and Stripping
of topsoil to a depth of 10-20 meters, with the soil being disposed of in a specified area or used to fill in and cover a former mining site.

Mining
of the layer of nickel ore measuring to depths of 5-10 meters, and the transporting of the ore to the screening station.

Screening
the ore is screened and classified by size at the screening station. The final product of the screening for Eastern type ore measures -6 inches, while the final product for Western type ore measures -4/-2 inches.

Storage
the screened/sorted ore is stored in a specified area in order to reduce the level of water content naturally, before the ore is further processed -- drying and re-screening – in the plant.

Revegetating
of former mining sites. In the case of the open cast mining methods now employed, in which materials from new mining sites are transported and disposed of at former mining sites, the follow-up steps include landscaping, the placement of layers of planting soil, terracing, and the development of drainage systems before the revegetating or replanting begins.