Optimization of Shovel-Truck Productivity in Quarries

In open pit operations, the loading equipment drives production but the haulage fleet drives costs. Most quarries in Malawi face challenges in shovel-truck productivity due to factors which require optimization of mine operations. The case of Njuli quarry is used to come up with a model that can be applied by quarries in Malawi. Loading and haulage costs account as much as 50 – 60 % of a company’s total operation cost hence it is necessary to maintain an efficient shovel-truck system. This research optimized the shovel-truck productivity per day, applied the queuing theory to the haul cycle, and suggested ways to improve the efficiency of materials handling operations. Examining a match between truck body size and shovel bucket size yielded the size of the load, cycle time and number of trips in an hour. The cycle time depended on the weight of the equipment, the horsepower of the engine, haul distance, and condition of the road plus dump area. Quarry companies in Malawi will apply this new knowledge to improve equipment selection and maximize the tonnage of aggregates produced per day to meet production targets.