A review of the hydro-mechanical behaviour of tailings and its importance to the stability of tailings dams

Abstract

Seepage in tailings storage facilities (TSFs) is commonly assumed to occur under gravity flow and is usually determined for steady-state conditions. However, the stability of TSFs is highly influenced by the degree of saturation of the materials involved in these structures. Several of these structures are in areas where the climate conditions are characterised by alternating (very) dry and (very) wet seasons, which presents additional challenges in terms of soil-atmosphere interaction. This paper presents a review of the parameters that influence the phreatic surface within the TSF under steady-state conditions and assesses by a numerical analysis of how this behaviour changes under transient conditions. For the modelling stage, a generic upstream dam setting is analysed using the limit equilibrium approach, where steady-state and transient seepage analyses are employed to assess the most influencing parameters on the dam's stability. Specifically, the hydraulic boundary conditions, the length, anisotropy and uniformity of the beach, and the effect of considering the drying or wetting path of the soil-water characteristic curve, are assessed to determine the degree of influence of these parameters on the stability of the dam.