A risk evaluation of bulldozer downtimes and its economic justification in open-pit mines

Abstract

The mining industry has been steadily expanding annually to keep up with the increasing demands. Consequently, used machinery needs to work efficiently, which indicates that unexpected downtimes should be at the minimum possible level. Proper identification and risk evaluation of the potential breakdown is the most important element for efficient equipment maintenance and breakdown prevention. This research has focused on its reliability function determination and analyzed the consequences of downtime and the cost of repairs over a period of one year. Delays on the observed mining machine were classified according to the type of downtime: mechanical, technological, power/electricity, and downtime due to external influences. Input elements for risk assessment were severity of consequence (S), probability of occurrence (O), and failure detectability (D). The method used in this paper is based on the cost of maintenance and the impact of bulldozer breakdowns on reliability in order to maintain profitability and, by reducing the number of unwanted events caused by sudden failure of parts, increase safety during operation. Results show that the monitored bulldozer belongs to the lowest defined risk class, so its use is economically justifiable.