The effect of compressed air pressure on mining production and energy demand

This paper describes an investigation into possible reasons for the decrease in productivity (and hence an increase in the unit of energy consumed) from underground pneumatic rock drills during the past decade. Recorded figures have shown that the volume of air needed to produce one tone has increased by 2.6 times from 2002 to 2013. Similarly, compressed air energy used per ton has increased by 4.6 times from 2002 to 2013. The aim of this paper therefore is to investigate the possible causes for this trend. The investigation includes the surface- and under-ground compressed air network and reveals system design inefficiencies as well as network losses. Possible engineering solutions to the said system inefficiencies are described. The authors are involved in implementing some of the solutions at one of the largest compressed air networks in South Africa. Energy savings of 2.1 GWh per month are expected.