Nickel laterite deposits in the Sorowako and Petea area are generally classified into two main types, West Block and East Block types, depending upon the nature of bedrock, the level of serpentinisation, ease of mining, size of boulders, degree of fracturing of the bedrock, optimum screen fraction that carries nickel grades, and the silica-to-magnesia ratios in the mineralisation.

West Block type deposits
These deposits are developed over a relatively unserpentinised peridotite bedrock; commercially mineable grades are confined to the -1" fines fraction; and silica to magnesia ratios are high (2.2 to 2.6 range).

West Block type deposits are categorized into Types 1, 2 and 3, depending on the degree of fracturing in the bedrock and the size of the resulting boulders. Type 1 deposits are the most difficult to mine due to weak fracturing of the bedrock and the resulting large size of the boulders. Type 2 and Type 3 deposits are successively easier to mine and are formed over more fractured bedrock resulting in boulders within the mineralisation profile that mining equipment can handle.

Optimum nickel grades in all West Block type deposits are confined to -1" screen fraction. Oversize is generally barren or very low grade. Exceptions exist in breccia mineralisation where siliceous garnierite carries respectable grades in the +1" fraction.

East Block type and Petea deposits.
These deposits are developed over bedrock that ........

The surface mining is not traditional pit mining but more an “open cast” system by truck and shovel where contour side cuts are made into a hill. Anywhere from eight to ten hills are actively mined to provide ROM that meets the quality specifications (ore chemistry) of feed for the nickel processing plant. Mining operations is supported by a number of facilities, including mining roads, heavy equipment, ports, fuel terminals, fuel pipelines, and fuel storage tanks. In 2022, company conducted an operational trial using one electric mining truck. The CXMG type XDR-80-TE electric truck was made in China and has a transport capacity of 70 tons with a number of advantages, one of which is automatic charging on downhill roads. Heavy Equipment 2022: 45 Excavators (20 to 200 Tons class) 110 Trucks (100–130 tons class)

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