This paper addresses the optimization of mineral supply chain operations under metal and material type uncertainties. A mathematical model to simultaneously optimize the mining decisions, the destination decisions, and consequently the cut-off grade, is proposed. A fix-and-optimize scheme that exploits the structure of the problem and uses relaxation and decomposition techniques is introduced to obtain an initial solution, and an adaptive large neighborhood search heuristic is developed to improve this solution. The proposed solution approach is tested on a copper-gold deposit. The results of these experiments show the ability of the proposed solution approach to efficiently address large instances of realistic size and provide schedules where the most valuable material is mined and processed early in the life of the mine and where the risk of not meeting production targets is reduced.
Published September 2015 , 28 pages