Three-Dimensional Seepage Simulation of a Tailings Storage Facility : A Case Study

Seepage response to tailings deposition and subsequent pore pressure condition characterization within the embankments of tailings dams are important in evaluating their performance under static and dynamic loading conditions. In this study, three-dimensional seepage response in a large tailings storage facility under tailings deposition and embankment raise was evaluated in the FEFLOW numerical platform. The simulation model considers interactions among the reclaim pond, deposited slurry, embankment, perimeter wells, and regional ground water table, analyzing both saturated and unsaturated flow conditions. The numerical model was first calibrated to the past and existing conditions, in which initial material properties were assigned based on field and laboratory testing, and then were adjusted through an iterative process until the pore pressure conditions in the model generally matched measured values. The documented piezometer measurements and pore pressure dissipation test results were used as calibration targets. The calibrated model was then used to project responses into the future for varied tailings deposition rates. The embankment crest and reclaim pond were evaluated in a series of raise steps over the time in a transient seepage analysis that accounted for consolidation-induced excess pore pressures under the increased overburden stresses. The effects of the raise rate, depositional scheme, and material water storage capacity on the projected pore pressure conditions were also evaluated. The results indicate that the numerical model can predict seepage response and pore pressure conditions reasonably well. The outcomes of such models provide more insights into the seepage performance of the tailings storage facilities. Additionally, pore pressure responses can be used in the framework of performance-based design to assist geotechnical engineers in evaluating embankment stability and to better inform decision-makers by reducing uncertainties. Such studies highlight the importance of using numerical models to evaluate the seepage response in tailings storage facilities. By providing a better understanding of the seepage performance, these models can help mining companies to identify potential risks and improve their management practices, ultimately leading to safer and more sustainable mining operations.Non UBCUnreviewedOthe