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 historical coal mining Frederick Sherrell Limited were asked to undertake and investigation to establish the extent of old mine workings.
Documentary records of the old mine workings were of poor quality and often incomplete so it was necessary to undertake an extensive programme of ground investigation including geophysics, trenching and drilling. The investigation confirmed the presence of backfilled surface excavations and shallow mine workings beneath the proposed road corridor, so it was necessary to design appropriate remedial works to protect the road from future settlement and ground subsidence.
The remedial works included a high strength geotextile (safety net) beneath the road, instu grouting to stabilise shallow mine workings and capping of mine shafts. During construction an engineering geologist from Frederick Sherrell Limited 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.