As the exploitation of an open-pit mine is evolving, the depth and therefore the distance traveled by the mine haul trucks increases. As a result, the operational cost of mining operation increases due to the higher consumption of fuel and tires. This work presents the evaluation of the performance of a truck fleet when using a trolley assist system. A model of the trolley system is developed using an active-front-end converter, which in combination with the integrated electric-mechanical model of a mining truck, allows quantifying the production increase, fuel savings, and net energy consumption during an up-down cycle of the truck. A set of evaluations are presented, first on idealized uphill and downhill routes, and then using the coordinates of a route of a copper mine located to the north of Chile. Results show a 44% increase in the upgrade speed, a 16% reduction of the travel time, and a fuel savings of over 85% on each up-down cycle. The tool developed allows evaluating the performance of a truck fleet in any mine facility just knowing the coordinates of the mine routes and the models of the trucks.