Water balance in filtered tailings storage facilities: laboratory tests and numerical simulations

ABSTRACT: Filtered tailings are often considered a promising alternative to conventional deposition methods and may contribute to improve the geotechnical stability of tailings storage facilities. However, the risk of generation of acid mine drainage (AMD) or contaminated neutral drainage (CND) can be increased by desaturation if the tailings are reactive. The objective of this study was to evaluate the influence of layer thickness and compaction on the hydrogeological behaviour of filtered tailings. Laboratory column tests were conducted. Volumetric water content (θ), suction (ψ), air temperature, relative humidity and evaporation rates were monitored during wetting and drying cycles. The preliminary results obtained in this study showed that there was no significant influence of thickness of the deposition layers on the behaviour of tailings. The development of a layer of salts at the surface of the tailings influences the evaporation rate and contributed to maintain a higher degree of saturation than expected.