Controlling operational dilution in open-pit mining

ABSTRACT Dilution and ore loss are important factors that can affect costs and profitability of a mining operation by lowering the quantity of mineral or metal that can be produced from each ton of processed ore. When discussing open-pit mining, dilution and ore loss are sometimes assumed as fixed factors in geostatistical block models and cut-off grade calculations, without considering specific particularities of the deposit and operation. This paper proposes to quantify the dilution caused by operational inefficiency through identifying the ore blocks that are a part of the short-term plans and mapping their neighbourhood, considering the nature of the contacts and the differences in grades. This technique enables the operational dilution to be calculated. It is applicable for operations using mechanical excavation and/or blasting. The results demonstrate that operational dilution can be measured and controlled to improve the tonnage and grade reconciliation between planning and production.