Thinking of developing a site in an area where historic coal mining may be present? Then you need a Coal Mining Risk Assessment (CMRA) as part of your planning application! This recent news story from the Coal Authority shows the dangers from unrecorded coal workings:
https://www.gov.uk/government/news/historical-unrecorded-mine-workings-stabilised-to-keep-scottish-community-safe
Many people are aware of extensive historic coal mining in South Wales, the Midlands, North and Northeast England and Scotland, but did you know there are also coal fields in Kent and around Bristol and Chester? Areas of coal mining risk can be determined by consulting the interactive map on the Coal Authority website (https://mapapps2.bgs.ac.uk/coalauthority/home.html)
Typically, a CMRA is required when the site is within a so called “High-Risk Development Area” although there are a few exceptions such as ancillary buildings, householder developments and solar arrays. A High-Risk area is defined as an area which can contain one or more recorded coal mining related features at surface or shallow depth and can be identified by using the Coal Authority Interactive map (https://mapapps2.bgs.ac.uk/coalauthority/home.html)
The CMRA, which is described by the Coal Authority here (https://www.gov.uk/guidance/planning-applications-coal-mining-risk-assessments#the-coal-mining-risk-assessment ) is a report that uses desk based research to appraise the risks associated with both recorded and unrecorded coal mining, i.e. open cast mining, shallow and deep workings, mine entries, geological faults, ground gas and so on. The information sources consulted include an up-to-date consultants’ coal mining report obtained from the Coal Authority, large scale geological maps, historical maps and records and, where available, mine abandonment plans and the findings of nearby intrusive investigations.
Based on an understanding of the impact of coal mining and the assessed risks to the proposed development, the CMRA will also contain a mitigation strategy to make sure the risk is managed appropriately and the site is developed safely. Mitigation might include the siting of a structure outside an area of risk, specially designed foundations, or a programme of ground treatment. In some cases, a site specific intrusive investigation will be required.
The CMRA is an interpretative report which requires a detailed understanding of geology to derive often complex ground models, especially as coal mining took place for hundreds of years before any formal records began to be kept. Not surprisingly, CMRAs can only be produced by professionals, including geologists and geotechnical engineers.
Concerned about your site? CampbellReith has a team of talented engineering geologists in Manchester, Bristol and the Southeast of England who can advise and, where necessary, prepare a CMRA for you!