The mining industry in its drive to optimise equipment use and minimise cost simply to remain profitable in an uncertain commodity market needs to develop a greater understanding of equipment capabilities and cost. The factors influencing mobile equipment fleet cost and performance commence at the time of mine planning and continue to exert an influence over the life of the mine. These factors must be understood at the early stages of any operation's planning process as they continue to impact both positively and negatively on fleet performance and operating cost throughout the life of the mine. The key factors examined in this paper include: grades; rolling resistance; fragmentation and truck loading.