A Practical Method for Compressed Air Leak Localisation in Deep-Level Mines

High electricity tariffs threaten the profitability of deeplevel mining in South Africa. Industrial compressors are one of the largest electricity consuming systems on a typical deep-level mine. These compressed air systems are also known to be very energy inefficient. Numerous electricity cost saving initiatives have been implemented to reduce compressor electricity consumption on mines. These initiatives, however, predominantly focus on reducing the compressed air supply to match the demand. Matching the supply and demand of compressed air is limited to minimum pressure requirements of end-users. Addressing the high underground demand, which can mainly be attributed to leaks, have been neglected due to the difficulty in identifying and quantifying underground inefficiencies. A new method has been developed to localise leaks to manageable areas in the vast underground compressed air system. In one of the case studies, the root cause of low compressed air pressure was found to be unregulated open-ended blowing pipes in the mining areas. It was estimated that conventional audits would have taken twice as long to identify these leaks. The removal of these and other unregulated air users resulted in an estimated annual electricity cost saving of R 1.4-million and increased the pressure for improved pneumatic equipment performance.