Optimally Locating Additional Drill holes to Increase the Accuracy of Ore/Waste Classification

چکیده مقاله

During different stages of a mine lifespan, planning the location of additional drill holes, based on the objective of that stage, becomes necessary. Most previous algorithms proposed for this purpose have aimed at reducing the block model uncertainty and enhancing the value of the drilling information as their objective functions, and have paid little or no attention to improve the precision of the ore/waste classification. Effort has been made in this paper to define, based on the misclassification probability parameter, an objective function for the optimization of the location of additional drill holes. Using the simulated annealing method in a phosphate mine, the efficiency of the proposed objective function has been validated and proven in optimally locating the additional drill holes. An advantage of this objective function, compared with the usual ones, is that in addition to having a direct relationship with the kriging variance, it depends highly on the estimated and cut-off grades; the more is the difference between these grades, the less will be the misclassification probability. Since these two grades remain unchanged with an increase in the number of the drill holes, the only way to reduce the misclassification probability is to reduce the estimation variance by drilling the additional drill holes in appropriate locations.