Fleet Sizing of Trucks in Open Pit Mines: A Case Study

Abstract

In open-pit mines, the dispatch system controller is responsible for determining the number of trucks operating in the mine. To do this, the controller considers the mine’s operating conditions, such as mining fronts in operation, the number of loading machines in operation, queues at loading and unloading points, and the idleness of the loading machines. Thus, this study addresses the truck fleet sizing problem (TFSP), seeking to minimize the number of trucks in operation according to the operational fluctuations during the work shift. A mixed-integer linear programming (MILP) formulation is presented for this problem. Although similar problems have already been addressed in the literature, this work has characteristics that have not yet been explored, such as truck capacity restrictions by material lithology, compatibility between trucks and lithologies, and loading and unloading locations. In addition, depending on the mine operation, the movement of material from each front can have a fixed or flexible destination. A mathematical solver was used to validate the formulation, and a case study with three instances from a work shift at a Vale S.A. copper mine was used. In all instances, the solver quickly found good solutions that could be used to support decision-making.