The effect of surface Bulk Air Cooler water flow on deep-level mine temperatures

Mine cooling and ventilation systems ensure favourable working conditions underground. Mines are hesitant to reduce the Bulk Air Cooler (BAC) water flow as doing so raises safety concerns. Previous studies on this topic compared the measured wet-bulb temperatures to the maximum allowable wet-bulb temperature of 27.5°C. This paper investigates how the temperature of the underground network is affected if the BAC water supply flow is varied, by comparing the wet-bulb temperature before and after flow control strategies are implemented. By reducing the flow through the BAC, it is seen that the wet-bulb temperature is not negatively affected and compares favourably to the baseline wet-bulb temperature. Testing this strategy showed a possible average peak demand saving of 3.75 MW and daily energy saving of 64.08 MWh. This study then went further and implemented this BAC water flow control strategy on mine A. During two months of the performance assessment period on the case study, an average daily Eskom evening peak power saving of 4.20 MW and daily average energy saving of 59.04 MWh was achieved. This verified the reduced energy consumption of the BAC flow control strategy.