Greenhalgh & Co.
Chartered Building Surveyors & Valuers
21 Towncroft Lane
Bolton BL1 5EN
Tel: +44 (0)1204 845382
Fax: +44 (0)1204 433968
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Mining Risk Assessment
Mining Risk Assessment is relatively new requirement for
Between the 23rd June 2015 and the 3rd July 2015 the Coal Authority published a series of maps.
These maps are collectively referred to as Coalfield Plans
for Local Planning Authority areas and are freely available on the internet and
can be found at: https://www.gov.uk/government/collections/coalfield-plans-for-local-planning-authority-areas#coalfield-local-planning-authority-plans
These maps, along with the Coal Authority interactive map
viewer give details of mining risk areas.
In essence areas of shallow coal workings, probable shallow
coal working, mine shafts and coal crops, are considered the main potential
risk area. The risk primarily stems from
the potential of subsidence or mining gas escape.... with subsidence being the
There are two different grades of risk: High Risk and Low
The High Risk Area (15% of the coalfield area) is where coal
mining risks are present at shallow depth which are likely to affect new
The Low Risk Area (85% of the coalfield) is where past coal
mining activity has taken place at sufficient depth that it poses low risk to
The risks are made up of the following:
Mine Entries with potential zone of influence
Past Surface Hazards
Past Shallow Coal Mine Workings
Probable Shallow Coal Mine Workings
Geological features (fissures and break lines)
Workable Coal Seam Outcrops
Surface (Opencast) Mining
The mining risk assessment in the Northwest is typically undertaken as follows:
1) Identify the site location (latitude and longitude)
2) Obtain an Environmental and Coal Authority report
3) Conduct a ‘Walk-over’ survey to identify any evidence
of previous mining related issues
4) If any existing buildings exist measure them for
structural movement in both the lateral and vertical plane.
5) Assess any movement in existing buildings against what
would be reasonable for the type and age of building given normal deterioration
6) Check the Environmental and Coal Authority report for likelihood
of ground problems.
7) Visual assess a sample of other buildings in the same
risk area for signs of subsidence.
8) Provide a risk assessment and if necessary a methodology
of mitigating the risk of subsidence and mining gas invasion.