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