Analysis of the Impact of the Dilution on the Planning of Open-Pit Mines for Highly Structural Veined-Shaped Bodies

Abstract

Currently, mining exploration is finding more small and thin deposits than massive copper porphyries. Therefore, vein deposits are becoming increasingly important in the mining business. A challenge presented by these ore bodies is the incorporation of operational techniques and practices that allow achieving sufficient selectivity to make the project profitable, not to mention that in certain geological contexts the structures present contaminants, which may create problems even for profitable operations in later stages. For this purpose, dilution should be treated as a fundamental factor, subject that in the current industry is little studied. The objective of this paper is to measure the impact of dilution in the planning of open-pit mines for highly stratified and veti-shaped bodies. For this, the following methodology is used, by means of a study of a fictitious deposit. First, a study is carried out on the dilution, its impact and ways of quantifying it in the industry. Then, several scenarios of different average grades are generated in the host rock, in addition to support changes, to verify the impact on a broad spectrum of cases, the proportions of the mineral in contact with waste are then indicated, thus quantifying the amount of resources to be diluted, followed by long-term planning, where the results of the proposed cases are finally collected and analyzed through key technical and economic indicators. It was found that as the block size increases, the contact surface between ore and waste increases, reducing the amount of ore without risk of dilution and, in the same way, reducing the waste, albeit in a smaller proportion. Finally, applying planning restrictions of blending and allowing a maximum dilution, there is a trade-off between the risk of diluting the resource and the value of the plan.