Mine tailings from various types of mining operations are often deposited on the area surrounding the mine site in the form of a slurry. The solids settle out over time and a tailings pile may have a number of lifts corresponding to deposition over different time intervals. The rate of drain-down of the wet tailings pile is of interest for understanding the mine site hydrology and stability of the tailings pile.

Numerical modeling of mine tailings can provide value in a number of specific areas: 1) Understanding the rate of discharge of contaminated water out of the tailings, and, 2) obtaining the pore-water pressure conditions at different deposition stages to aid in stability analysis, and, 3) estimation of long-term groundwater conditions. Problems are commonly encountered in numerical models of mine tailings due to the following reasons:

• Mine tailings typically have irregular 3D geometry.
• Mine tailings are often deposited in different lifts at different stages of the mine life requiring proper specification of initial conditions and staged models.
• Mine tailings deposited as a slurry become unsaturated over time and therefore require a numerical model capable of handling the particular nonlinearities associated with unsaturated seepage modeling.

SVFlux has been successfully applied to mine tailings drain-down applications and proven itself capable of matching results obtained in the field. Specifically, the following features make SVFlux the premier tool for evaluating mine tailings drain-down operation:

• The automatic mesh generation allows quick meshing of complicated 3D problems.
• 2D and 3D analysis are available.
• Advanced formulations and algorithms to handle nonlinear unsaturated analysis.
• Highly detailed mesh generation allows representation of fine features such as the overliner material, preferential flow paths, multiple soil regions, irregular internal geometry, or decreasing hydraulic conductivity with depth.
• Initial conditions can be set per soil region to simulate wet placement of tailings and provide an accurate water balance.
• Automatic mesh refinement allows accurate calculation of wetting fronts in dry soils.
• Surfaces of existing topography can be created and input into the model from survey data.
• Climate data such as precipitation, temperatures, and net radiation may be incorporated into the model for analysis of long-term cover performance.
• Staged solutions allow modeling of the actual sequence of tailings lifts.