Using GPR, Electromagnetics (EM) and Electrical Imaging / Resistivity, GEOTEC Surveys map the sub-surface environment, for a range of features.

Geophysical Approaches & Applications

Typical features which can be located are:

  • mine shafts, coal shafts and buried wells
  • old foundations/ building lines, footings and pile caps
  • basements & cellars
  • tunnels, cavities and underground voids,
  • dissolution features
  • buried tanks

Tools & Techniques

GEOTEC Surveys Ltd evaluates the objective of each survey in line with the site characteristics in order to assign the best tools for meeting the needs of the client. We also look to use a number of methodologies in conjunction with one another in order to provide the best possible result, where possible.

Ground Penetrating Radar (GPR):

Ground Penetrating Radar (GPR) is a versatile tool which can be used to meet a range of objectives which are summarised below:

We can use a range of systems and antennae to survey to a variety of depths (0.5m to 10m) within a myriad of different environments and also have the capacity to use a Vehicle-Mounted GPR System.

EM31 / CMD Explorer:

We combine GPR Surveys with the EM31 / CMD Explorer in many cases to assist us in locating features such as mineshafts, air raid shelters, tunnels, dissolution and buried structures, as shown by the examples below:

Example of a Mineshaft Survey

Example of a Roman Road

Example of a Buried Structure and Void following a sinkhole discovery

This tool has a depth penetration of 6m below the ground surface and is particularly good at achieving data collection across larger areas over a shorter time frame than other methods, however is susceptible to the presence of surrounding metallic interference.


An EM61 offers a non-invasive alternative for UXO (Unexploded Ordnance) or UXB (Unexploded Bomb) Surveys. This is essentially a survey to detect and map significant buried metallic objects which may be synonymous with UXO. We offer this as an initial feasibility survey to assist clients before deciding whether they need support from a specialist provider.

Example of unexplained anomalies detected on a railway embankment

If you would like to discuss any of the above approaches, please call Julian, Tom or Luke on 01428 686168 to identify whether any of these or a combination, would meet your requirements.

Survey Request


Methods & Techniques

  • Radio Frequency
  • GPR
  • Resistivity / Imaging
  • Electro Magnetics
  • Micro-Gravity

Resistivity / Electrical Imaging:

Bedrock Profiling using Imaging/ Resistivity assists clients to:

  • ensure piling is securely installed,
  • map the extents of oil pipeline and water leaks.
  • assist in cable route design.
  • locate the water table.
  • provide evidence of fissures/ caves / tunnels/ mines.
  • as a follow up to EM31 / CMD electromagnetic surveys to offer more information on the above.

Resistivity survey sample

A full cross section can be provided showing the contours and make-up of the ground reaching a depth of 30m into the ground.

Case Studies

Related projects