Approximately 11% of the British Isles lies within former coal field areas, where shallow mine workings may exist. Shallow coal mining, where worked coal seam voids may be <30m below ground level, exist over 15% of the coal field. Therefore 85% of the coal field areas may not require any specific investigative action. In addition to mining voids, there are approximately 171,000 recorded mine entries in Britain, including vertical mine shafts, underground mine shafts and adits.
A Coal Mining Risk Assessment (CMRA) has been a statutory planning requirement since 2011 for developing high-risk areas, where shallow coal mining voids may exist. Patrick Parsons’ CMRA reports are compiled using data supplied by the Coal Authority, British Geological Survey and other sources of information such as the Durham Mining Museum and the Institution of Mining and Metallurgy. Approximately 75% of sites where a CMRA has been undertaken will recommend a physical investigation of the ground to confirm the underground mining status.
We have extensive expertise in ground investigation for former mining features, including:
- Trial pits and trial trenches
- Rotary openhole and coring
- Mines gas and risk assessment for carbon dioxide, carbon monoxide, methane, oxygen depletion and hydrogen sulphide
- Application of geophysics
From our desk and field-based risk assessments and CMRAs, we will then provide design advice to mitigate mining risk such as:
- Drilling and grouting design and specification
- Mine shaft cap design
- Costing of mine working stabilisation
- Foundation design, mitigation and advice
- Design mitigation for roads and car parks
- Obtaining regulatory approvals