Abstract:Three important aspects of phase-mining must be optimized: the number of phases, the geometry and location of each phase-pit (including the ultimate pit), and the ore and waste quantities to be mined in each phase. A model is presented, in which a sequence of geologically optimum pits is first generated and then dynamically evaluated to simultaneously optimize the above three aspects, with the objective of maximizing the overall net present value. In this model, the dynamic nature of the problem is fully taken into account with respect to both time and space, and is robust in accommodating different pit wall slopes and different bench heights. The model is applied to a large deposit consisting of 2 044 224 blocks and proved to be both efficient and practical.

Key words: open-pit; phase-mining; dynamic programming; optimization