The techno-economical impact of reducing chilled water usage on a deep level gold mine

Abstract

Deep level gold mines make use of refrigeration plants to chill water for use in underground operations. Operating these plants as well as pumping the used water back to surface result in significant costs. To reduce this operating cost of a deep level mine, an investigation into different areas of the operations was done to determine whether chilled water usage could be significantly reduced. This study focusses specifically on reducing the chilled water usage at the underground dewatering pump motor coolers, as a significant amount of chilled water is consumed for cooling purposes. This study proposes alternative methods of cooling and discuss the physical implementation thereof. The three chilled water reduction strategies investigated include converting from an air-to-water motor cooling strategy to an air-to-air cooling method, installation of automated solenoid valves, and the use of clear water for motor cooling purposes. By implementing these strategies at a case study mine the chilled water flow has been reduced by 50 l/s, which relates to a R 13.3 Million financial saving in terms of operational costs