Design, construction, and performance of a single geomembrane liner system at a residual waste disposal site in western Pennsylvania

This paper examines the effectiveness of a single geomembrane-lined deep valley coal ash/coal mine refuse disposal site to maintain ground-water quality after 10 years of operation. The site occupies over 81 hectares (ha) [200 acres (ac)] in western Pennsylvania. The effectiveness of the liner system was evaluated based on an assessment of the site`s ground-water quality. The liner system was designed in 1983. Selection of geosynthetics and drainage materials, interface shear values, and construction control methods were based on laboratory testing, field investigations, slope stability analyses, and construction load analyses. Diligent construction quality control was applied during all aspects of site development. To examine the site`s ground-water quality, the ground-water monitoring network was sampled approximately once every six weeks for one year. Results of statistical analyses show that the liner system is effectively separating disposal site leachate from ground water and that the site is not degrading ground water.