Cost effective management strategies for platinum mine cooling systems

Abstract

Due to economic reasons, the demand for platinum has decreased in countries that previously consumed it in large quantities. Electricity, diesel fuel, reinforced steel, wages and salaries play a big role in the rising costs within the South African platinum mining sector. Amongst these expenditures, electricity costs increased most. Therefore, platinum mining companies have to minimise costs where possible. Because refrigeration systems are one of the systems that consume the most electricity on a platinum mine, energy saving strategies are necessary on these systems. Incentive programmes provided crucial financial support for implementing energy saving projects to save possible electricity costs. Eskom's Integrated Demand Management (IDM) funding has been restricted due to financial constraints. Therefore, a need exists for ESCos to implement cost effective strategies. Investigations were done on existing load management strategies that included load shifting, load clipping and energy efficiency through control strategies. In this study, a mine was reviewed by evaluating the layout, system specification, cooling requirements and operations. A simulation model was developed together with a cost effective control and monitoring strategy. The strategy was simulated on a mine and the results proved that the strategy would be feasible. The strategy was implemented on the cooling system of a mine by using existing infrastructure and labour. Savings were achieved by switching off the main energy-consuming components during Eskom's evening peak period (18:00-20:00). This helped the mine achieve energy savings and energy cost reduction without high implementation costs. The implementation period was short and no funding was required. An average demand reduction of 4 MW was achieved during tests. As a result, an estimated annual cost saving of R1.53 million was achieved by implementing this strategy. The dissertation proves that manual control and monitoring can be done on platinum mine refrigeration systems. Although manual control and monitoring require low implementation costs, automated DSM projects are still more reliable and sustainable. Manual control and monitoring are short-term alternatives when the client or ESCo are not able to afford the implementation of automated DSM projects.