A target-based performance tracker for mine energy monitoring

MEng (Electrical and Electronic Engineering), North-West University, Potchefstroom CampusSoftware systems play a major role in the day-to-day operation of deep-level mines. These systems range from quantifying production and energy use to monitoring seismic activity. As deep-level mines expand to reach more minerals, the software systems become more difficult to maintain, as they need to be scaled up. One aspect which needs constant monitoring through the software systems is the mine energy usage, which affects a significant portion of the mine’s profitability. With the constant increase of electricity tariffs, energy-wastage events should be minimised as far as possible to ensure profitability in implemented projects. Presently, deep-level mines in South Africa primarily make use of a supervisory control and data acquisition (SCADA) to monitor the mining systems. The advantage of a SCADA is its real-time capabilities, which enable constant monitoring of underground processes. This method, however, has two limitations which will be discussed further in this study, namely a lack of a baseline or reference point and a lack of an optimised interface. Due to these limitations, energy-wastage events go unnoticed. Additional methods also discussed in this study to monitor the energy usage include reporting and monthly budgets; however, they carry limitations which make them unable to stop energy wastage as they occur. In this study, the limitations of the existing energy-monitoring methods are evaluated, and a new monitoring system is proposed. The proposed monitoring system will aim to increase efficiency in implemented projects through mitigating energy-wastage events as they occur. The new method fundamentally focuses on benchmarking the energy use and creates energy usage targets which are project specific. These targets act as a guide which the projects must not deviate from if energy savings in implemented projects are to be maintained. The new targets are implemented in two forms, namely as a new prioritised information system to enhance the SCADA so that monitoring personnel can more easily make informed decisions, and as an SMS (short message service) notification system to track and react to wastage events as they occur. The proposed monitoring system was implemented on existing projects in a mining group in South Africa, and the case study results show a positive change in addressing unexpected energy-wastage events. It proved to be effective in mitigating energy wastage in a compressed air network integration project to the value of R96 000 through ensuring a compressor is not operated outside of the project scope. This intervention ensured that the project did not deteriorate but maintained savings in a twelve-month period. In the second case study, the monitoring system mitigated energy wastage in pumping load-shift projects by ensuring pumps were not operated during the more expensive peak hours. In the case study, an annual negative cost impact of R0.2-million is projected to be mitigated using the monitoring system on the specific mining shaft. This value is expected to reach R2-million annually when the monitoring system is implemented on the entire mining group. In the third case study, the monitoring system was successful in mitigating energy wastage in a turbine generator project through ensuring that electricity generation was uninterrupted. Active user engagement was promoted with its optimised visual interface in the fourth case study. The proposed monitoring system met the objectives of the study and ensured that energy savings were maintained in implemented projects through mitigating wastage.Master