Dewatering optimization using a groudwater flow model at the Whitewood open-pit coal mine, Alberta

Dewatering optimization of the Whitewood open-pit coal mine was achieved using a finite-difference groundwater flow model. The model was modified extensively to simulate site-specific conditions. A transient calibration of the model was performed to simulate observed water levels and the model was then used to devise a dewatering well scheme in which the number, locations and pumping rates of vertical wells varied with time. A total of 54 wells have been successfully installed and operated. An investigation of the effectiveness of the dewatering well program showed that a marked decrease in head occurred adjacent to the mine highwall. Coal recovery increased, and operational problems and spoil pile failures decreased since the commencement of dewatering in 1982. The background to the modelling exercise, modelling program details, and an assessment of the effectiveness of the well system are described.