Nifty Heap Leach Re-Mine

Sedgman provided the detailed engineering and procurement services for the 3 Mt/a Nifty Heap Leach Re-Mine Project copper processing.

The Nifty Copper Project is located in the Pilbara region of Western Australia and initially produced copper cathode, from the oxide ore, via heap leaching, solvent extraction and electrowinning.

At the end of mining the oxide ore, the project converted to mining and processing the sulphide ore to produce a copper concentrate for sale.

The heap leaches were to be reclaimed, repulped, screened and hydraulically classified. The screen oversize and the hydraulic classifier oversize were refed to the heaps for further leaching while the classifier undersize would report to the tailings thickener. Lime slurry would be added to the tailings thickener to neutralise the slurry and to precipitate any solubilised copper. The thickener underflow would report to the tailings storage facility and the thickener overflow would be recycled as process water.

SCOPE OF WORKS

The project scope included the following:

• Involve the re-mining of the existing Nifty heap leach pads
• Scrubbing of the material and desliming using screening and hydraulic classification to remove clay material that has previously impeded heap leach recovery
• Restack coarse material on the pads for leaching and the fines thickened, neutralised and disposed of in a tailing’s storage facility.

The work comprises the detailed engineering and procurement assistance generally.