Primary producer of platinum-group metals Anglo American Platinum (Amplats) reports that the ore-replacement project at its Khuseleka mine, in the North West, is almost 75% complete.
Amplats says the Khuseleka ore-replacement project aims to replenish the diminishing Merensky reef output and supplement the existing upper group two (UG2) output at the UG2 shaft by extending the existing decline shaft.
The ore reserves are being accessed through the existing Merensky decline cluster section, with the Merensky ore mined between 25 and 28 level and the UG2 ore being extracted between 15 and 28 level.
The ore-replacement project will allow Amplats to safely exploit the UG2 reserve in the Khuseleka decline shaft and make optimal use of the overall ore tonnage capacity at Khuseleka. It also enables a major extension of mine life.
The project forms part of the strategic approach at Amplats’ Rustenburg operations to tackle the declining Merensky reef reserves by extending the lower-grade UG2 and optimising shaft infrastructure.
The associated project infrastructure includes three ventilation shafts, which were completed in 2010. The shafts are 3 km away from the main Khuseleka vertical shaft and they intersect the decline system on the 26 level, which is about 821 m below the surface.
Development on the UG2 section of the project is 56% complete, says Amplats.
The project will be completed in the first quarter of 2015 and will see the replacement of 70 000 oz/y of platinum.
Meanwhile, the project has created a demand for additional ventilation in the lower decline area.
A R60-million surface refrigeration plant was built to provide the required ventilation and cool the air temperature at the Khuseleka shaft. It is now fully operational after being commissioned in 2010.
The 8.7 MW refrigeration plant and auxiliary equipment provide 600 kg/s of air under- ground. The air is cooled to 18 ºC all year round. It operates at 5 MW on ice making mode and 8.7 MW at full capacity.