Energy Audit and Management Opportunities for a Diamond Mine: A case for Lets’eng Diamond Mine

Abstract

The mining sector is highly energy intensive. Undertaking mining activities at a geographic location bearing extremely cold temperatures like Lets’eng in Lesotho exacerbates the situation as abundant energy is required to provide the comfort needed by employees. Nonetheless, there exists ample waste in energy use within the mining sector which can be avoided by bringing forth energy management strategies. The study firstly identifies areas of energy waste and their cause. Both simple and technical energy management strategies are employed in correcting ways of energy use in order to utilise the least possible energy. The aim of the study is to minimize energy costs at the mine and reduce environmental damage associated with electrical energy use while also integrating renewable energy technologies where it is possible to do so. Monthly energy consumption profiles from electrical meters at the mine were used to analyse the consumption patterns of different energy processes. The study identified energy management opportunities in the energy processes of lighting, space heating, water heating and poor power factor. Energy management interventions for all the opportunities identified were economically assessed in terms of their cost of implementation and operation against the associated energy savings they would yield. All the recommendations proved to be economically viable as they resulted in a positive Net Present Value (NPV) and all Payback Period in years were within the remaining life of the mine which spans until 2034. Modelling gives a total of 41 903.14 tonnes of greenhouse gases averted from emission to the environment as a result of implementation of energy management opportunities.