Linear Programming Model Applied to Long-Term Mine Planning in Strip Mining Operations

Strip mining is largely employed in horizontal tabular deposits near the surface, such as coal and bauxite deposits. The deposit is first divided into panels, which are mined using parallel cuts called strips. The strips are a set of contiguous and subsequent blocks. The challenge is to determine the year of extraction of a set of blocks to maximize the total profit while respecting a series of boundary constraints. Many algorithms have been developed to solve this problem in an open-pit context. However, their application to strip mining operations has not been fully tested. In this paper, we propose a method to indicate the best period of extraction for each block in this kind of surface mining method. First, the method finds the best block sequence within each panel. Second, a linear programming model is used to find the optimal ore mass coming from each panel that maximizes the total profit. Last, the results of the panel optimization are used to update the block model at the block scale. The optimization is performed sequentially for a number of periods/years. The methodology is illustrated in a case study with data obtained from a real bauxite mine. The results show a feasible mine schedule that honours the mining capacity.