Optimally Locating Additional Drill holes to Minimize Misclassification Error - A Case Study of Angouran Deposit

 
During different stages of a mine lifespan, planning the location of additional drill holes, based on the objective of that stage is necessary. Most of the previous algorithms proposed for this purpose aim to reduce the block model uncertainty and enhance 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. In this investigation, effort has been made 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 the Angouran mineral deposit, the efficiency of the proposed objective function has been validated and proved in optimally locating the additional drill holes. An advantage of this objective function, compared with the common 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.