Undersea longwall mining subsidence with special reference to geological and water occurrence criteria in the North-East of England coalfield

Abstract

To date the use of classical statistical techniques for the identification and analysis of parameters which control the occurrence of water on longwall panels has proved inconclusive. An alternative and potentially more meaningful approach is to examine the interaction between the tensile strain induced by mining and the geological and hydrogeological environment surrounding the workings. After a brief description of the geology and hydrogeology of the North-East of England Coalfield, the paper examines in detail the water yield—predicted tensile strain and geological-strain water relationship occurring at four collieries with extensive undersea workings: Blackhall, Horden, Dawdon and Westoe. In each case, water occurrences can be correlated with either faces worked in the vicinity of a major fault (where aquifer horizons are displaced against Coal Measures strata overlying the working horizon) or areas where the amount of cover to the base of the major aquifer horizon thins appreciably or a well developed, potentially water bearing sandstone horizon exists within the intervening Coal Measures strata.