Optimization of Open-Pit Mine Depressurization System Using Simulated Annealing Technique

Abstract

Opencast mines operating in an area with dominant groundwater features may face hydrology-related problems such as heaving and bursting of the mine floor due to excessive uplift pressure. A proper groundwater control system has to be implemented to solve these problems. But the groundwater control system, which includes dewatering and depressurization wells may also create impacts on local groundwater flows. Therefore, an optimization-based development of the groundwater control system is required to ensure that local and regional hydrogeological impacts are within acceptable limits. This note presents a case study where an optimization program based on the simulated annealing technique was developed and applied to a three-dimensional seven-layer groundwater model. The calibrated groundwater flow model, which is based on MODFLOW, was used as the simulation component in the linked simulation-optimization model. The combined model was then used to identify the optimum depressurization strategy. The results show that this combined simulation and optimization methodology is a viable approach for solving large-scale groundwater management problems.