The Investigation of a New Road Scheme Near an Old Coal Mine in North Devon



Coal mining in North Devon was carried out at East-the-Water and Bideford in the 18th, 19th and early 20th Centuries.  When a new road was planned across an area of suspected historic coal mining Frederick Sherrell Ltd were asked to undertake a site investigation to establish the extent of the mine workings.

Documentary records of the old workings were of poor quality and often incomplete so it was necessary to undertake an extensive programme of on site investigations including geophysics, trenching and drilling.

The investigations confirmed the presence of backfilled surface excavations and shallow mine workings beneath the proposed road corridor and it was therefor necessary to design and install remedial works to protect the road from future settlement and ground subsidence.  The remedial works included installing a high strength geotextile safety net beneath the road, insitu grouting to stabilise shallow mine workings and capping of mine shafts.

During construction Frederick Sherrell Ltd maintained a watching brief to ensure the remedial works were carried out in accordance with the design and to provide additional geotechnical advice as and when required.