Abstract
Geosynthetic clay liners (GCLs) have been greatly used in landfill liners and covers since their introduction in the mid-1980s. The low permeability and high attenuation capacity offered by the Na-montmorillonite in GCLs suggest that they may be beneficial also in the mining industry. Even though GCLs have been studied for several years, there is very limited research assessing the compatibility of GCLs to extreme chemistry leachates such as acid rock drainages (ARDs) generated from mining or construction excavation. This paper aims to present the results of heavy metal release per year and predict the concentration in the groundwater after 10 years of service from GCLs applied in rock waste containment facilities with the potential of ARD generation using 1D advection-dispersion equation. Parameters used in the calculations such as hydraulic conductivity and partition coefficients were obtained from experiments (hydraulic conductivity and sorption tests). For simplification purposes, the depth of the groundwater was assumed to be constant and equal to 10 m, the porosity equal to 0.4, and the groundwater velocity to 45 m/s. The results differ according to the type of ARD, but in majority of the cases it fulfilled the Japanese groundwater and effluent Quality Standard requirements.
