Engineering a novel automated pump control system for the mining environment

Abstract

South Africa is experiencing serious electricity supply problems. A major concern is the high peak electricity demands between 18:00 and 20:00. This peak is primarily caused by the growing residential sector. Unfortunately, changing people's behaviour to reduce the evening energy peak is difficult. An easier approach will be to focus on other sectors such as the industrial and mining sectors. South African mines contribute 18% of the country's electricity consumption. Of the total mining electricity bill 40% is consumed by water pumping systems. Manual load shifting is attempted on approximately 15% of these pumping systems. The results are not sustainable due to maintenance problems and system complexities. By automating, simulating, optimising and controlling the pumping systems of deep level mines, sustainable load shift can be achieved. This will also reduce the running cost of mine water pumping system due to time based electricity pricing. With this research a novel solution is presented. This unique automated tool simulates, optimises, schedules and controls any pumping configuration in a unique integrated fashion. The new system was tested in 13 case studies, involving a wide variety in terms of layout, size, and equipment types. More than 39 MW of load was consistently shifted out of the evening peak. This resulted in cost savings of more than R 5,7 million per year for the mines involved in the case studies. This system also has other benefits. Automated systems require fewer personnel such as pump attendants, leading to more savings. The system also provides better safeguard against the risk of flooding, and faster training of new control room personnel. The benefits for ESCOs are fast and accurate predictions on the savings potential of specific pump configurations. These and other benefits indicate that the new control system should be rolled out on all large pumping systems.