NR Somers, project manager, High-Point Rendel. The paper was first published in GE’s August 2000 edition.
Eggborough and Ferrybridge coal-fired power stations dispose of some of their ash residue by pumping it as a slurry to Gale Common where it settles out in lagoons. In order to provide additional protection against seepage into groundwater, secondary HDPE liners were installed in the lagoons on top of settled ash. The ash is generally formed of silt-sized particles and the foundation for the secondary liners was expected to be very soft under the wet conditions. The design and construction of the liners is described, including a review of construction in similar conditions and a site trial to determine safe methods of construction.