In June 2013, KTI had been awarded a first contract to supply 2 x 200 t ice plants and extend an existing surface ice plant at the Harmony Phakisa gold mine in South Africa. KTI says it successfully demonstrated the technical feasibility and the economic viability of the containerised ice plant concept.  As previously covered on im-mining.com, the trial 400 t/d plant was pre-fabricated in record time at the German KTI factory in Balzheim and delivered to site in early November 2013. It was then erected and commissioned in just 10 days. Once the plant was in full production, an average daily production of 440 t/d was achieved.

This successful result has now led to a second extension phase, adding four new plate ice plants of 1 MW each. They will be supplied along with a new 1.5 MW water chiller, raising the overall capacity at this mine to 3,300 t/d.

Where gold extraction reaches 2,400 m below surface, the virgin rock temperatures can be greater than 50°C. Furthermore, the excavating activity creates additional heat that must be fought. In view of the underground heat rejection limitations and costs in deep mines, the introduction of ice from surface becomes a viable alternative. The latent heat of fusion of the ice provides pure cooling energy. Each kilo of ice absorbs 334 k J as it melts, far more than cold water. Ice is easily conveyed down the main shaft and reaches the 1,800 m level in a matter of seconds. Hence the ice-cooling system reduces the pumping costs at the mine to less than 20%.