Investigating the dewatering energy savings potential of an open pit mine

Abstract

The South African mining industry is heavily reliant on its electricity supply from Eskom. Due to the increasing cost of electricity, it is crucial to reduce the consumption thereof and thereby increasing the profitability of an operation. While underground mining is heavily reliant on electricity, open pit mining is, in addition to electricity, more exposed to logistical and fuel cost. Both types of operations have significant energy cost savings potential with regards to the dewatering of the mine. The aim of this study is to develop an open pit pumping methodology, taking Eskom time-of-use periods into consideration, to decrease the electricity expenses of a case scenario mine. This will be accomplished through an in-depth investigation into load shift possibilities using the dewatering infrastructure available. With the use of validated mathematical models, different scenarios are evaluated to improve the savings. For the case study mine the pumping methodology results indicated substantial energy savings obtainable. The operations investigated can shift 1,496,805 kWh out of the peak time of use period which translates to R2,107,609 of energy cost savings per annum. Based on this case study there are definite potential for savings at other open pit mining operations across South Africa.