Reclaimers and stacker reclaimers of nickel ore for mines in New Caledonia

Uničov, 20 August 2004

The engineering-foundry complex UNEX a.s., producer of technological units, mechanisation parts, and casts, has produced for the firm of Voest-Alpine Materials Handling the fundamental parts for two machines - a reclaimer and stacker reclaimer of nickel ore -, which are to work in the regions of Tiebaghi and Doniambo in New Caledonia. An inspection assembly of both machines was also carried out in Uničov. The machine parts were transported to New Caledonia by ship via the port of Hamburg.

The loader for the region of Doniambo will be assembled in the existing nickel smelting works in Noumea and has an average projected capacity of 850 t/h on a conveyor-belt 1400 mm wide and 22 m long.

Due to the unusual arrangement of materials in Doniambo, some interesting operational procedures are in use, resulting in some inspired elements to the proposal.

The Doniambo dump is arranged so that the new loader will carry material stacked above the central line of the machine's track. Loading in this way clears a path for the loader to move along the rails. The bucket-wheel excavator removes material at a nominal height of 100 mm above the rails and the ore is finally cleared from the rails by a hydraulic dozer situated in front of the leading wheels.

The loader can work on either of two parallel heaps of material and it moves between the two dumps along a freight track running to the end of the dump. The ‘self-transporting' works in such a way that the loader positions itself at the junction between the working and freight tracks, where hydraulic jacks always lift one side of the machine allowing the axle group to turn 90 degrees (by means of hydraulic cylinders) and change orientation from one track to the other. As soon as the machine is positioned on the second working track, the procedure is reversed and the machine is ready to load material from the second pile. The entire haul should take less than one hour.

The material is carried along a hand-cranked discharge belt onto fixed conveyor-belts running parallel to the rails and at the foot of the pile.

Due to the increased loading efficiency and also due to the fact that it is possible to remove viscous material on one level, the loader is equipped with a vertically-rotating system of raking shovels above the bucket-wheel excavator, which rakes the material downwards and prevents excessively sharp angles in the conveyor-belt.

The stacking loader for Tiebaghi has an average projected capacity of 1200 t/h on a conveyor-belt 1400 mm wide and 30 m long. This machine has a more traditional design. One exception is the fact that it contains a clod cylinder under the central hopper, which breaks up sticky material and enables it to flow smoothly.