Influence of stope geometry on sloughing and dilution in open stope mining

This paper investigates the influence of stope geometry irregularity on stope sloughing and dilution. A comprehensive dilution database including mine design and geotechnical data from a local mine in Kazakhstan was established. The stopes were categorized into three shape classes depending on the extent of the irregularity, simple, semi-complex and complex geometry. First, numerical modelling was performed and the results suggested that the stope with complex geometry was found to have the highest effect on sloughing and dilution in terms of strength factor and tension. Next, the Rock Engineering System (RES), was used to define the dilution index (DI) for each category of stope geometry. The results revealed that the stope category had the most significant effect on the dilution index. In addition, the stability numbers corresponding to the stopes in this study was calculated and the accompanying stability graph was plotted for comparison purposes. The plots of the dilution index and stability number for all of the stope categories showed good correlations. This indicates that the DI can not only quantify the effect of stope geometry irregularity, but also can be used to evaluate the stope dilution.