Geophysics for Detection of Mine Workings Mining legacy Mining activity has left a legacy of workings such as bell pits, shafts and adits that have a significant influence on both modern developments and existing infrastructure. A lot of mining activity is well documented, but in some cases, the reliability and accuracy of this information can be uncertain. A TerraDat geophysical survey coupled with selective intrusive investigations can provide a rapid and cost-effective means for locating shallow abandoned mine-workings. Given limited historical/remediation information and the influence posed by present- day site conditions (e.g. fill material, buildings, services, roads etc), shallow mine- workings have historically proven to be difficult targets for geophysics. TerraDat addresses this by adopting an integrated survey approach comprising a number of different geophysical techniques that target both direct (e.g. shaft lining/cap, void space) and indirect physical properties (e.g. localised variations in drainage patterns or backfill material) of buried targets. Typically, TerraDat utilises a combination of Electromagnetic, Magnetic and Microgravity techniques. These can be complimented with Ground Penetrating Radar and Resistivity techniques should further information be required. Rapid Coverage Integrated Survey Approach Vertical and areal characterisation Technical Note Clay rich back-filled bell pit Shaft-related geophysical targets Resistivity section over a former bell pit Circular anomaly associated with capping structure Ground conductivity survey targeting shaft cap Ground truthing of circular geophysical anomaly 10m Reinforced Cap / support structure Localised variations associated with ground settlement or in-fill material (metallic debris) Density contrast associated with void space or backfill material TerraDat (UK) Ltd - Tel (08707 303050) www.terradat.co.uk *Cost Effective *Non-invasive *Rapid Ground Coverage *Environmentally Friendly *Swift Mobilisation/Global Coverage Contact Simon Hughes for more info; [email protected]

Abandoned Mineworkings - Geophysical Technical Note

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TerraDat is a UK based specialist geophysical ground exploration company that operates worldwide. Geophysical surveys provides a rapid, non-invasive ground investigation tool that has many applications ranging from locating buried manmade structures through to characterising geological and hydrogeological features. This TerraDat Technical Note deals with how geophysics can benefit ground engineering problems associated with shallow abandoned mineworkings.

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Page 1: Abandoned Mineworkings - Geophysical Technical Note

Geophysics for Detection of Mine Workings Mining legacy

Mining activity has left a legacy of workings such as bell pits, shafts and adits that have a significant influence on both modern developments and existing infrastructure. A lot of mining activity is well documented, but in some cases, the reliability and accuracy of this information can be uncertain. A TerraDat geophysical survey coupled with selective intrusive investigations can provide a rapid and cost-effective means for locating shallow abandoned mine-workings.

Given limited historical/remediation information and the influence posed by present-day site conditions (e.g. fill material, buildings, services, roads etc), shallow mine-workings have historically proven to be difficult targets for geophysics. TerraDat addresses this by adopting an integrated survey approach comprising a number of different geophysical techniques that target both direct (e.g. shaft lining/cap, void space) and indirect physical properties (e.g. localised variations in drainage patterns or backfill material) of buried targets.

Typically, TerraDat utilises a combination of Electromagnetic, Magnetic and Microgravity techniques. These can be complimented with Ground Penetrating Radar and Resistivity techniques should further information be required.

Rapid Coverage

Integrated Survey Approach

Vertical and areal characterisation

TechnicalNote

Clay rich back-filled bell pit

Shaft-related geophysical targets

Resistivity section over a former bell pit

Circular anomaly associated with capping structure

Ground conductivity survey targeting shaft cap Ground truthing of circular geophysical anomaly

10m

Reinforced Cap /support structure

Localised variations associated with ground settlement or in-fill material (metallic debris)