Methodology of simulation of underground working in metal mines. Application to a uranium deposit in Australia

For the Ben Lomond (Northern Queensland Australia) underground uranium mining project, studies were carried out to compare the feasibility of different mining methods according to their cost per ton and selectivity, i.e. cut and fill, sublevel stopping and both mixed. First, a geostatistical orebody model was built. The ore grade variability of this model results from the drillhole structural analysis. Working on two dimensional vertical cross sections, the usual hand drawing stope reserve estimate obtained with computer assisted design for each of the three different mining methods is compared with the results obtained with automatic algorithms allocated to the characteristics of each mining method. These algorithms use mathematical morphology to reproduce the geometrical constraints connected with each mining method and/or dynamic programmation. These techniques lead to fully automatic of optimal economical stope design. Comparison is positive: automatic stopes designs are in agreement with hand made drawings, but they can be defined faster through interactive questionning of the computer, and the total maximum profit obtained is a least as high as the best profit found through hand designed projects