Contaminated groundwater around a former coal carbonisation site - A case history

ABSTRACT

Several former coke works sites in north-east England are under consideration for redevelopment for residential or commercial use. In some instances the contamination from the coking processes has spread off-site through groundwater and investigations have been undertaken to ascertain the extent of contamination. This paper focuses on one very large site covering 91 hectares, Hawthorn Colliery, where contamination may have spread onto the so-called Hawthorn Reserve Site through groundwater movement. Details of investigations and proposed remedial measures are provided. At Hawthorn the services of an industrial archaeologist were engaged to research details of the actual operations at the colliery since their commencement in 1957. This enabled the site investigation to be focused on areas of highest contamination potential. A phased approach to the investigation was carried out and at the end of each phase both the geological and contamination aspects were assessed and examined thoroughly in order to economically plan each subsequent phase. The investigation concentrated on locating the thickness and extent of sand and gravel layers within the glacial till and determining the permeability of these layers, as these layers provide a potential conduit for contaminants from the former colliery site to the adjacent Reserve Site.