Iron Ore Economic Optimisation

CIM Montreal 2015
Pierre-Jean Lafleur (P.J. Lafleur Géo-Conseil), Robert Ethier (Consultant)
Strategic Mine Planning Optimization based on Mineralogy
Iron Ore deposits consist of a multitude of iron minerals. Major minerals are typically hematite, magnetite or taconite representing iron oxides. Follows goethite and limonite representing hydrated oxides. Minor iron minerals found in the host rocks are pyroxenes and amphibolite representing the main ferrosilicates. It is easy to get an assays for total iron but to distribute the analysis between the various iron ore minerals for mine planning is more complicated. To assess the economic value of iron ore requires to differentiate iron minerals. A good understanding of the iron ore market is essential to understand the variations and correlations between the iron ore products in time to optimize the strategic mine plan. A detailed analysis of the data allows to use magnetism measured with Satmagan and/or Davis Tube to model the various iron minerals in the mineral resources. This model allows to calculate with precision the hematite, magnetite content and the weight recovery of iron excluding silicates of iron (without value) depending on the total iron grade. This model of iron minerals must match with the geology and mineralogical analysis to be used to optimize the strategic mine planning. Using the Whittle software of Dassault Systems (GEOVIA), a simple example demonstrates a potential 50% increase of the NPV for the iron deposits of the magnetite-rich Labrador Trough. To accomplish this goal requires to simultaneously optimize the size and the shape of the pit, phases, the mining sequence as well as the process and quality of iron concentrate produced by the plant.
Keywords: Value, NPV, Optimization, Processing, Product Specification, Economic, Mineralogy
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