Utilising automated control principles to reduce compressor operating costs on mines with limited infrastructure

Abstract

The mining industry faces severe challenges with increasing operating costs at above-inflation rates, particularly the cost of electricity. Compressed air systems are extensively used on mines, making up roughly 20% of the total power consumption on most sites, while on platinum mines this figure can be as high as 38%. This makes compressed air systems a prominent candidate for the implementation of energy efficiency solutions. Research reveals several popular solutions that can improve the efficiency of compressed air systems. However, these solutions require systems to be outfitted with specialised instrumentation and/or software. Thus, systems that are devoid of the required instrumentation and/or software need to be upgraded before savings can be realised. To address this problem, the fundamental principles behind these strategies were used to develop a solution that could generate savings with existing infrastructure and little to no prior investment. A need, therefore, existed for a simplified methodology that uses the fundamental principles behind popular compressed air control strategies to achieve energy savings. A methodology was developed and implemented as case studies on two mine compressed air networks. The case studies verified the accuracy of the developed solution and validated the solution results. Implementation produced an average total cost saving of R13.7 million annually at 2022 Eskom rates, which deviated from the expected savings with an error of less than 5%. This study was successfully implemented on platinum mines where energy efficiency solutions have not yet been established, exceeding the expected target outcomes. It is recommended that this solution be implemented in industry where energy efficiency projects are still in their infancy. Alternatively, the developed methodology can be used on established sites to expand and implement solutions where the needed instrumentation is not yet available.