Data driven block discretisation method for predicting the bulk ore sorting benefits applied at distinctly heterogeneous open pit mines

Recent mining technology innovations such as robust shovel bucket mounted sensors allow ore grades to be measured at the mine face for every scoop and truck during extraction. There are currently limited established methods for estimating the ore control benefits of enhancing mining selectivity at a given deposit. A discretisation method is presented using blasthole grades where a selective mining unit block is first discretised to truck or shovel bucket sized subblocks. Subblock grades are assumed to follow a distribution with the same average grade as the host block and the variance scaled from locally surrounding blastholes. The ore control benefits are quantified by comparing the ore and waste grade tonnage of the coarser original blocks to the more selective subblocks. The discretisation methodology is applied reducing the selective mining unit on 2 months of production data from three distinctly heterogeneous open pit mines. Discretising to truck sized blocks resulted in a 10–30% decrease in dilution and ore loss depending on the coefficient of variation, strip ratio, average grades above and below cut-off, and spatial continuity. Operational considerations for bulk ore sorting are provided as productivity could be impacted as a tradeoff for the enhanced selectivity.