Haul Truck Speed Analysis and Effect on Fleet Optimization

Abstract

Over the years, truck-shovel operation has been established as the primary hauling methodused in open pit mines. Since the haulage cost can be as high as 50 percent of the total operating cost in a particular mine, numerous studies addressed optimization of truck-shovel operations. Different fleet management systems have also been used at many open pit mines to increase the productivity and hence reduce the overall cost. Although these management systems help optimize the truck assignments, the impact of the truck operator behavior on the overall machine availability and productivity has always been difficult to quantify. With the introduction of autonomous trucks into the mining industry in the last decade, the effect of truck operators on machine availability and productivity has been a very critical factor in comparing manned vs autonomous trucks. The misuse of brakes during hauling will cause the trucks to be late for their assignments. In addition to time loss, it will cause extra fuel loss, which are both very critical cost items for any mine. Using brakes unnecessarily will also cause more maintenance time and this will reduce truck availability. Bad road designs, such as unnecessary stop signs at intersections, can be another factor of time loss. This research presents a new intersection passing algorithm based on the priority of each truck when they approach an intersection point at the same time. It calculates the criticality based on various parameters such as load status, speed, payload amount, material type, and current distance to the intersection. A simulation model is created to measure the effect of the new passing algorithm on productivity, efficiency, and fuel consumption. Ad-hoc speed suggestion is also calculated for each truck to use while passing the intersection points. The results of the simulation are compared with other traditional methods that have been used for decades, such as Loaded Truck First (LTF), First Come Fist Serve (FCFS), 4-Way stop models.