Medium-term Rail Planning at Rio Tinto Iron Ore

In minerals supply chains, medium term plans over time horizons from two weeks to two years are used not only to maximise throughput and identify bottlenecks, but also for scheduling crews, production and maintenance. These plans need to observe constraints like maintenance and production requirements, fleet capacities, and dumping, loading and stockyard management at every site. Additionally, the iron ore supply chains considered in this paper also needs to deal with grade quality constraints. This introduces extra complexities in terms of non-linear constraints as the quality depends on the mixing ratio of ore from different sources. We present an optimisation tool that was developed for Rio Tinto Iron Ore for such planning. The tool provides optimal number of trains while taking into account all the system constraints and has already reduced total planning time significantly.