Global diversified technology and multi-industrial leader Johnson Controls installed two additional York YK centrifugal chillers at platinum mining company Impala Platinum (Implats) for the planned second phase expansion of cooling capacity for its Impala 16 Shaft as it heads toward a depth of 1 650 m.
The start-up of the extension commenced last month, with the new chillers being in operation by the end of that same month.
The surface air cooling plant for 16 Shaft was designed and established in 2008 by mine ventilation and refrigeration specialists Bluhm Burton Engineering Consulting (BBE), that were appointed by Implats to provide a turnkey solution that included the design, construction and commissioning of the overall refrigeration plant and air cooling system.
“The cooling plant is designed to facilitate six chillers in total as production builds up and demand for cooling increases. The first two chillers, also York machines, were installed almost ten years ago and we are now entering the second phase of the cooling expansion,” says BBE director Richard Gundersen.
Johnson Controls operating manager Russell Hattingh states that the two 7 MWR York YK chillers are newer models of the two York machines initially installed. The chillers deliver improved performance and offer a wider operating envelope, while still meeting the Impala standard.
“BBE prides itself on its independent supplier approach when designing ventilation solutions. We select solutions that will meet the needs of the project. Cooling is mission critical for mining operations, so the requirement for chiller solutions must be robust, reliable and efficient.”
The cooling solution, including the first two refrigeration machines, the initial two condenser cooling towers, the complete spray chamber shells, and spray piping for the first phase of bulk air cooling, was constructed in 2008. For the second phase, two new machines have been installed and two new cooling towers have been constructed, to add the 14 MWR of cooling.
“We need air cooled to about 13 ºC on the surface so that the working areas, at a depth of 1 650 m, are below the legal working limit. The virgin rock temperatures are 55 ºC at these depths, so cooling is vital for production. Water is chilled by the refrigeration machines and sprayed into the horizontal spray chambers.
“Axial flow fans force ambient air through the spray chambers and into the barrel of the main (downcast) shaft to reach the underground workings. With the added cooling capacity, Implats will meet the environmental needs of the workforce,” Gundersen notes.
Hattingh says Implats has confidence in York chiller solutions. “The mine has used the York chillers across its operations for more than two decades, consistently selecting them for proven reliability. The custom requirements we build into the equipment for Implats has become a standard for mining solutions on the continent. “We are pleased to be able to continue supplying Implats and are committed to ensuring our York chillers meet the stringent demands of specialists such as BBE and they get the highest level of support from our teams.”
Meanwhile, the third and final phase of cooling will be rolled out in five to ten years’ time, increasing cooling capacity to 42 MWR.