A Critical Investigation into the Real Cause of the Low Heavy Mining Equipment Reliability: A Case of AZ Open Pit Mine, West Africa

Mining is heavily dependent on large and expensive equipment, therefore, it is important to efficiently manage the performance of the capital intensive equipment to remain productive. The performance of the major mining equipment (Dump Trucks and Excavators) at AZ Mine, not the real name, was continuously below budge from 2019 to 2020, a condition that adversely affected productivity of the mine. The mine management attributed the low equipment reliability to poor supervision in the Heavy Mining Equipment (HME) department and extended lead-time of maintenance spares, however, this assumption was not supported by any formal investigation or research. It is for this reason that the study was conducted to investigate the actual cause of the low reliability of the HME at the mine. Reliability and Maintainability characteristics; Meantime Between Failure (MTBF) and Meantime To Repair (MTTR) as well as failure mode patterns of the equipment are studied. Data collection is through document review from planning office, participant observation and through views of key informants (subject matter experts). Tables and graphs are used to present data trends and their characteristics. The study has therefore, concluded that, the major contributing factors to the low equipment reliability of the HME at the mine are lack of Heavy Equipment Repair skills to work on the high technology equipment. The Local Technicians, though constituted the largest number compared with the skilled Expatriates, were not adequately trained and the onsite training provided was not sufficient. Further, there was no established spares management plan to assist in prioritising and forecasting parts acquisition. The maintenance infrastructure did not support the HME operations and the department run without a formalised maintenance strategy. To summarise the factors responsible for downtime, a framework to show the main causes of the low equipment reliability with intervening variables was developed. Final