Benchmarking electricity use of deep-level mines

Abstract

Electricity consumption, and the cost thereof, has become a large contributor to operating costs in deep-level mining in South Africa. Up to 60% of electricity used on deep-level mines can be attributed to five high power demand systems that continuously operate for maximum production output. Compressed air, cooling, dewatering, ventilation and hoisting systems form part of these high demand systems. The need to reduce electricity consumption of high power demand systems is identified as a means to increase mining profit. Various initiatives that aim to increase energy efficiency of high power demand systems have been implemented. However, these initiatives are often driven by external parties with no stake in mining profitability. It is important to create awareness of system performance in terms of comparative energy consumption to start focusing on identifying possible energy efficiency initiatives for mines. Numerous energy benchmarking studies have been conducted on systems ranging from commercial to industrial. The focus of these studies was on increasing energy consumption awareness and, in doing so, identifying the need to reduce energy consumption. The objective of this study is to benchmark the electricity use of deep-level mines in a new way that considers relevant external factors and variables. New models were created using actual data obtained from South African deep-level mines. Models for both average and best practice benchmarking were developed. A novel technique for determining the priorities of energy efficiency initiatives on high demand systems was also developed. This study creates additional real-time awareness by developing a new method to determine operational energy budgets. 2015 Benchmarking electricity use on deep-level mines. The developed models and techniques were verified by using external methods. The models were then validated by applying them to the high power demand systems of nine case study mines. The results showed that the benchmarking, prioritisation and dynamic energy budgeting models accurately distinguished between efficient and inefficient mine systems. With the knowledge obtained, awareness of system-specific and overall energy consumption was achieved and mitigating initiatives could be implemented.