Germany-based refrigeration company KTI-Plersch Kältetechnik announced last month that it received a large order to cool a South African gold mine with a surface ice system, which will be used to cool the two-kilometre-deep mine and will provide a total capacity of 8 MW.
The company explains that, where gold extraction reaches 2 400 m below surface, the virgin rock temperatures can be greater than 50 ºC. 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, as the latent heat of fusion of the ice provides pure cooling energy.
“Each kilogram of ice absorbs 334 kJ as it melts, way 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%,” KTI explains.
KTI was awarded its first contract to supply two 200 t ice plants and extend an existing surface ice plant at a South African gold mine, in June 2013. KTI successfully demonstrated the technical feasibility and economic viability of the containerised ice plant concept.
The trial 400 t/d plant was prefabricated in record time at the KTI factory in Balzheim, Germany, and delivered to site in early November 2013. It was then erected and commissioned in just ten days. An average daily production of 440 t/d was achieved once the plant was in full production.
This resulted in the gold mine hastening the second extension phase, adding four new plate ice plants of 1 MW each. It will be supplied along with a new 1.5 MW water chiller, raising the overall capacity at this mine to 3 300 t/d.