| Operating an open pit mine requires a large number of planning steps, either for the site analysis, the organization of facilities or the management of production activities. Such planning is complex as the activities to plan are numerous and highly co-dependent. In this project, we are primarily concerned with the problem of planning in the medium term (i.e. a period of up to 3 months) of these activities. This problem consists of finding the processing order for the blocks of the mine, while minimizing production costs. These sequences must respect the precedence relationships between blocks, the mixing constraints, the movements of the shovels and the grouping of blocks for drilling / blasting.;First, an optimal method making use of resolution strategies is presented. Among these strategies, we find the setting of variables, the setting of priorities for the tree branching and the inclusion of constraints and parameters with the property of eliminating symmetries in the solutions. The use of such strategies is essential and improves the solution time dramatically.;Subsequently, a heuristic exploiting the intuitiveness of extracting blocks in a direct sequence is developed. This method relies on the establishment of an intuitive sequence which is then strongly suggested to the solver during the resolution through discounts in the objective function. The results show that this approach achieves very good solutions quickly for models of size much greater than the models which can be solved optimally.;This level of planning for open pit mining has received little attention in the literature so far. Thus, we propose a model consisting of mixed integers (MIP) with which we establish the organization of operations and the removal sequence for the blocks of the mine. Two resolution methods are developed to use this model. |
