Assessment and improvement of topsoil and subsoil loading and hauling operation at Manungu Colliery

Abstract

This study investigated optimising the stripping load, and haul operation at Manungu Colliery to boost productivity amid declining global coal demand and the operation’s production shortfalls. As coal prices continue to drop due to the shift toward greener energy sources, improving operational performance has become critical to maintaining profitability. The study involved a baseline assessment to evaluate key performance indicators (KPIs), including time utilisation, hauling conditions, loading efficiency, and cycle times. Interventions aimed at improving these KPIs were then implemented during an intervention study. A mixed-methods approach combined quantitative data from production reports, survey records, time studies, and shift logs with qualitative insights from observations and interviews with the operation’s personnel. Results from the time studies, document reviews, and observations were analysed to identify feasible interventions for increasing production while maintaining or reducing input levels. The implementation of targeted operational adjustments led to measurable improvements. In May 2024, production increased by 27% compared to March, with a 32% cycle time reduction due to improved haul routes and flatter ramps, while diesel efficiency improved by 12%. By November 2024, the year-to-date production had a positive variance of 9%, compared to a 27% negative variance in the 2023 financial year, highlighting the effectiveness of the implemented strategies. The findings indicate that continuous operational improvements boost efficiency. Challenges like adverse weather conditions and limited direct supervision persisted. Recommendations include integrating advanced technologies, expanding the scope to include a cost-benefit analysis of the improvement efforts, conducting prolonged studies, and focusing on environmental impacts. The study provides a framework for enhancing productivity through data-driven strategies and operational best practices in open-pit mining operations.