Numerical Modelling of Pumped Hydro Scheme at Rehabilitated Mine Site

Numerical groundwater modelling was conducted to investigate the feasibility of using a open pit mine as a pumped hydro site (PHES scheme) after mine closure. A FEFLOW model was constructed and PESTPP-IES software was used for both parameter optimization and uncertainty analysis. The calibration process produced one-hundred and fifty alternate realizations of model parameters available for predictive uncertainty analysis. Four predictive scenarios were simulated and included: prediction of the final pit design and pit lake recovery; daily operation of the PHES scheme; Long term PHES operation and two-hundred year recovery and; particle tracking and contaminant transport. The changes in groundwater level due to the PHES scheme and the likely pathways of contaminants of concern were identified and potential flowlines produced.