Mineshaft imaging using surface and crosshole 3D electrical
resistivity tomography: A case history from the
East Pennine Coalfield, UK
Jonathan E. Chambers
, Paul B. Wilkinson
, Alan L. Weller
, Philip I. Meldrum
Richard D. Ogilvy
, Simon Caunt
British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK
The Coal Authority, 200 Lichfield Lane, Berry Hill, Mansfield. NG18 4RG, UK
Received 16 June 2006; accepted 8 March 2007
Hidden mineshafts located in urban areas are a significant problem across much of the industrialized world. Electrical resistivity
tomography (ERT) is a technique that can detect and characterize hidden mine entries by exploiting resistivity contrasts between
the shaft and surrounding materials, resulting from either compositional or structural differences. A case study is presented in
which both surface and crosshole 3D ERT surveys are used to image a hidden backfilled mineshaft at a built environment site,
situated on Carboniferous Lower Coal Measures strata in the UK.
Backfilled shafts generally present the greatest challenge for detection using geophysical methods, as contrasts between the fill
and bedrock are typically low compared to air or water-filled conditions. Nevertheless, the shaft in this case was identified by both
the surface and crosshole 3D surveys. The shaft appeared as a strongly resistive anomaly relative to background materials, which
we interpreted as resulting from the disturbed fabric of the fill materials rather than any significant compositional differences. The
study highlighted the respective strengths and weaknesses of the surface and crosshole ERT methodologies for this type of
problem. The surface survey, which covered a non-rectangular area to accommodate irregular boundaries and other physical
obstructions, provided a relatively rapid means of investigating the study site. However, this method had a limited depth of
investigation and was constrained in its coverage by the locations of buildings. By contrast, the 3D crosshole method was able to
image the shaft to the level of the deepest borehole electrodes. Although crosshole ERT is too expensive to be used for large-scale
mineshaft surveys, this study clearly demonstrates its suitability for targeted investigations where surface methods cannot be
deployed, such as scanning beneath surface structures or in situations where it is essential for resolution to be maintained with
© 2007 NERC. Published by Elsevier B.V. All rights reserved.
Keywords: Electrical resistivity tomography (ERT); Abandoned mineshaft; 3D modelling; Crosshole; Geohazards
Journal of Applied Geophysics 62 (2007) 324 – 337
Corresponding author. Tel.: +44 115 936 3428; fax: +44 115 936 3261.
E-mail address: email@example.com (J.E. Chambers).
0926-9851/$ - see front matter © 2007 NERC. Published by Elsevier B.V. All rights reserved.