Chapter 14 Geological hazards from salt mining, brine extraction and natural salt dissolution in the UK

Salt mining along with natural and human-induced salt dissolution affects the ground over Permian and Triassic strata in the UK. In England, subsidence caused by salt mining, brine extraction and natural dissolution is known to have occurred in parts of Cheshire (including Northwich, Nantwich, Middlewich), Stafford, Blackpool, Preesall, Droitwich and Teeside/Middlesbrough; it also occurs around Carrickfergus in Northern Ireland. Subsidence ranges from rapid and catastrophic failure to gentle sagging of the ground, both forms being problematical for development, drainage and the installation of assets and infrastructure such as ground source heat pumps. This paper reviews the areas affected by salt subsidence and details the mitigation measures that have been used; the implications for planning in such areas are also considered.