Block size selection and its impact on open-pit design and mine planning

In mining projects, the design and production programmes are developed on the basis of a block model. This model requires defining, assessing and assuring many important parameters used in the feasibility study and that may have relevant consequences over the future results of the project. The selection of such parameters is a complex engineering decision due to their great economic impact on the mining operation, as they will significantly affect the mine design and planning. For example, concerning the block model, there are many decisions involving the grades of the elements of interest, by-products and impurities, the dilution percentage, the selectivity and the rock density. A fundamental parameter of this model is the choice of the block dimensions, since this will condition mining dilution and selectivity, affecting the operation and mining costs. The objective of this study is to quantify the influence of the block size on the mining selectivity and its impact over the projects final economic results (income, costs, and discounted cash flows), a topic that has not been systematically studied in the literature so far.