The heap leach method of mineral extration using sodium cyanide has resulted in low cost extraction of minerals (gold, silver and cooper) from low grade ores. Polyethylene geomembrane is used as an impermeable flexible barrier to prevent containmination of the soil and groundwater by the chemical extraction solutions, as well as the recapturing and recycling of the solutions.
In tailing dams it provides a secure membrane between the tailings pile and the environmnt, including drinking water, as it is able to withstand the pressure exerted onto it by the tailings and the sharpedges from the tailings pile.