Economic lifetime of a drilling machine: a case study on mining industry

Underground mines use many different types of machinery during the drift mining processes of drilling, charging, blasting, loading, scaling and bolting. Drilling machines play a critical role in the mineral extraction process and thus are important economically. However, as the machines age, their efficiency and effectiveness decrease, negatively affecting productivity and profitability and increasing total cost. Hence, the economic replacement lifetime of the machine is a key performance indicator. This paper introduces an optimisation model that gives the optimal lifetime for a drilling machine. A case study has been done at an underground Swedish mine to identify the economic replacement time of a drilling machine. It considers the purchase price, maintenance and operation costs, and the machine's second-hand value. Findings show that the economic replacement lifetime of a drilling machine in this mine is 96 months. The proposed model can be used for other underground mining machines.