Case studies

• Customer: Cundall Johnson & Partners
• Project: Mineshaft Detection - Washington Galleries Bus Depot
• Date: 2004
• View survey results (pdf)

Cundall Johnson & Partners (CJP) are currently involved in a major redevelopment of the bus terminal at the Washington Galleries Shopping Centre in Tyne and Wear. Following a desk study exercise carried out by CJP, a drawing relating to a capped former mineshaft within the bus depot was found. On the basis that the record drawing indicating the position of the mineshaft was approximately 30 years old it was not possible to verify its accuracy and it was agreed to implement underground mapping to more accurately locate the position of the mineshaft and overlying concrete cap.

A two-stage strategy for the detection and mapping of the mineshaft and concrete cap was developed by Geotec using a combination of Ground Penetrating Radar and Micro-Gravity techniques. The survey was carried out within an area 400m2 in size and was implemented at night to minimise traffic risk due to the site being an active bus depot.

The overlying concrete cap was successfully identified and mapped at a depth of 2.60 metres below ground level. The mapped position confirmed that the mineshaft was approximately 2.50m west of the original record drawing position.