The potential role of geosynthetic clay liners in mine water treatment systems

Combined passive treatment technologies have been used to treat acidic rock drainage (ARD), the well-known acute and costly environmental problem facing the mining industry. It is shown that geosynthetic clay liners (GCLs) were able to attenuate metals from lime treated ARD water, and maintain a neutral pH and low hydraulic conductivity (less than 4.0 × 10−11 m/s) after 16 pore volumes of permeation; this implies their usefulness as a potentially significant component in combined passive treatment systems. Presented are laboratory breakthrough data for Cu, Cd, Ni, Mn, and Zn from the permeation of GCLs with 16 pore volumes of ARD, treated ARD (TARD), and a landfill leachate. Metal retention occurred in all solutions, but was greatest for the TARD, producing removal efficiencies of greater than 80%.