Improved ventilation control of an integrated deep-level gold mine using simulation

Abstract

The gold mining industry in South Africa has experienced a decline in productivity, primarily due to rising operational costs, including high electricity tariffs. In addition, ventilation and refrigeration systems, responsible for significant electricity usage in gold mines, contribute to operational inefficiencies, necessitating new initiatives to improve ventilation systems and reduce operational costs. Simulation software enables accurate representation and understanding of complex deep-level ventilation systems, aiding in assessing airflow distribution and ventilation networks. In addition, such simulations facilitate the identification of energy-saving opportunities and the evaluation of their feasibility. Integrated ventilation networks add new branches and ventilation control devices to an increasingly complex system, thus increasing the difficulty of managing the ventilation networks and creating the need for simulation software to evaluate the system. Minimal literature was found on improving integrated ventilation networks using simulation software and ventilation control. Thus, this study aimed to develop, using existing research, and implement a new method to improve integrated deep-level gold mine ventilation systems using ventilation control methods and simulation software to reduce operational costs. A four-phase method was developed from existing literature to improve integrated ventilation networks using simulation software and ventilation control methods in deep-level gold mines. The phases are 1) system investigation, 2) simulation development, 3) strategy development, and 4) implementation and evaluation. The proposed method was applied to improve the ventilation network of a gold mining complex consisting of three integrated shafts (A, B, and C). In the first case study, a simulation was developed to address a pending labour strike, requiring a reduction in ventilation electricity demand. Based on the simulation results, it was decided to switch off one surface fan on Shaft A and increase the frequency output of the remaining fans. This implementation lead to a demand reduction of 1.8 MW, resulting in cost savings of R 3.48 million over a three-month period. In the second case study, it was identified that the fan cowling of surface fan two was broken, leading to increased frequency outputs across all fans to compensate for the reduced airflow. With the aid of the simulation, a lower-frequency output was chosen and implemented after the fan cowling was repaired. Consequently, the electricity demand decreased by 0.74 MW, leading to annual savings of R 7.16 million. The findings highlighted the new method’s effectiveness in improving integrated ventilation networks and achieving substantial energy and cost savings in gold mines using ventilation control methods and simulation software. The study emphasised the significance of implementing energy-saving initiatives to reduce operational expenses in the gold mining industry while maintaining safe working conditions.