Effective methods to reduce grade variability in iron ore mine operations

This paper explores possible strategies to meet iron ore customer requirements (reduce variability and keep Fe% and contaminants such as Al₂O₃% and P% within the acceptable tolerance) by optimizing the mine plan and scheduling strategy in the rehandling process. The paper aims to obtain more homogenous iron ore grade by redesigning current rehandling strategy and creating selective Run of Mine (ROM) with defined Fe grade and contaminants tolerances in the supply chain process. A new Linear Programming Model was developed and sample data from an Iron Ore operation in Western Australia was used to conduct this analysis. The outcomes indicate that it is possible to achieve better grade results for Fe% and Al₂O₃% keeping required tonnage targets. Furthermore, the results reflect Low-Grade materials could play a more important role in the weekly schedule and that grade contents could balance alterations of High-Grade products. Although there are extra costs due to rehandling activities, these costs could be offset by selling more consistent products. It is an invitation to mining companies to change current strategy and focus more on the downstream and customer requirements in terms of quality product instead of just quantity.