Checking coalfield referral areas before you fix a layout
A shaft under a plot moves buildings, not foundations. Check the coalfield referral status at appraisal, before the layout hardens around something that cannot be built on.
A recorded mine shaft under a plot does not change the foundation design. It changes where the buildings go. That is why the coalfield check belongs at appraisal, in the same hour as the flood map and the heritage layers, rather than at the point a ground investigation report lands on a layout that has already been priced.
England's coalfields cover a large part of the north east, Yorkshire, the east and west Midlands, Lancashire, the north west and parts of the south west, and within them the mining authority defines development high risk areas. A site inside one triggers two things: a coal mining risk assessment submitted with the planning application, and consultation with the authority on that assessment.
Running the check
The mining authority publishes an online map service showing whether a location falls within a development high risk area. It is free, it takes a postcode or a grid reference, and it gives a yes or no answer in under a minute. The national planning data service also publishes coalfield related datasets alongside the other constraint layers, which is convenient when you are batch checking a pipeline of sites rather than looking at one.
That check tells you the regulatory position. It does not tell you what is under the site. For that you order a mining report, which draws on the authority's records of mine entries, recorded workings, past subsidence claims, licensing and gas emissions. Two products exist, one aimed at conveyancing and one at development, and the development version is the one that carries the information a designer needs.
Order the report before exchange on any site in a referral area. The cost is trivial against the cost of discovering a capped shaft in the middle of the only viable access route.
Reading what comes back
Four findings change a scheme, in roughly descending order of pain.
Recorded mine entries. A shaft or adit with a known position, and usually a stated diameter and treatment history. The position is recorded to a tolerance rather than a point, so the constraint is a zone rather than a dot. Buildings, and often gardens, are kept out of it, and the entry itself may need locating, proving and treating.
Recorded shallow workings. Seams worked close to the surface, typically by pillar and stall methods, leaving voids that can collapse. Treatment usually means drilling and grouting across the affected area, which is a measurable cost per square metre and a programme item.
Mine gas. Methane and carbon dioxide migrating from workings, which brings in gas protection measures to the guidance on ground gas, with the characterisation following the usual site investigation standards. This interacts with any contamination work already planned.
Spoil and surface features. Tips, opencast backfill and old surface plant, which affect ground stability and sometimes contamination.
The report also flags whether the site is within an area of past or current licensed mining activity, and whether there are outstanding subsidence claims. That last item matters for existing buildings on site, and it belongs in the brief for any structural survey of a retained structure.
The risk assessment the council wants to see
A coal mining risk assessment is a desk based document with a clear job: identify the coal mining legacy features that affect the site, assess the risk each one presents to the proposed development, and set out what investigation and mitigation follow. It is not a substitute for ground investigation and it does not need to be, provided its conclusions lead somewhere.
What makes one persuasive:
- A plan showing every recorded feature, drawn on the proposed layout rather than on a blank site outline.
- A stated standoff for each mine entry with the reasoning behind it.
- A clear statement of what intrusive work is proposed, where, and at what stage.
- Conclusions the authority can consult on without asking for more information.
What weakens one is a generic summary of the coalfield with no engagement with the layout. Officers and the mining authority both read these regularly and the difference is obvious on the first page.
The assessment sits alongside rather than inside the other ground documents. A geotechnical assessment covers bearing capacity, settlement and foundation options. A land contamination assessment covers the phase 1 desk study and the conceptual site model for contaminants, which overlaps with mine gas without duplicating it. Keep the boundaries between them explicit, because a condition discharged against one report does not discharge the others.
Permits, and why they take time
Any intrusive activity that will enter or disturb coal, mine workings or a mine entry needs a permit from the mining authority before it starts. That covers site investigation boreholes into workings, grouting programmes, shaft treatment and excavation that intersects a seam.
Applications are assessed, and the authority can attach conditions on method, monitoring and reinstatement. Build the lead time into the programme. A rig booked for a Monday with no permit is a wasted week, and on a phased site that delay propagates.
The permit is separate from planning permission and separate from the building control process. Nobody else can grant it.
Sequencing it properly
- Referral area check at appraisal, before an offer.
- Development mining report ordered, read alongside the geological desk study.
- Constraints plotted on the concept layout, with standoffs applied to recorded entries.
- Coal mining risk assessment prepared, informed by the layout as drawn.
- Permit application and intrusive investigation programmed together.
- Treatment designed, priced and, where required, secured by planning condition.
Steps three and four are the ones people reverse. Writing the risk assessment before the layout exists produces a document that says "further investigation is required" and nothing else, which the mining authority will say so.
An illustrative case
Illustrative example. A brownfield site of 1.4 hectares inside a development high risk area. The mining report records one shaft near the eastern boundary, position accurate to within a stated radius, treated in the 1970s with no record of the method, plus shallow workings across roughly a third of the site. The layout is redrawn to place public open space over the shaft zone, with the road alignment shifted 12 metres west. Grouting is programmed for the workings under the housing parcels only. The figures and distances are illustrative and the site specific report governs.
What the check cannot do
Records are incomplete, particularly for workings that predate systematic recording. Unrecorded shafts are found regularly, usually by a drilling rig or an excavator. A clean mining report reduces risk without eliminating it, and the site investigation is what closes the gap.
Non-coal mining sits outside this system entirely. Ironstone, tin, lead, gypsum, chalk, clay and building stone workings are patchily recorded, and in some districts the local authority or the geological survey holds better information than anyone else. Ask the council whether it holds a local mining or cavity register, because several do.
Enter the site postcode on PlanScope to see which ground related documents a site is likely to need, and browse the full report index to scope the wider evidence base.
This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required.
Frequently asked questions
How do I check if a site is in a coalfield referral area?
Use the mining authority's online map service, which shows whether a site falls within a development high risk area, alongside the national planning data published on planning.data.gov.uk. Both are free to search. A formal mining report, ordered separately, gives the site specific record of shafts, shallow workings and past subsidence claims.
What is a coal mining risk assessment?
A desk based report identifying recorded mine entries, shallow workings, mine gas, spoil and surface hazards affecting a site, with conclusions on what intrusive investigation and mitigation are needed. Authorities in development high risk areas require it with the application, and it should be prepared by someone with relevant mining and ground engineering experience.
How close can a building go to a mine entry?
There is no single national figure, and the answer depends on the shaft diameter, the depth, the recorded treatment and the ground conditions. A standoff based on a zone of influence around the entry is normal practice, and the mining authority comments on the proposed approach. Treat any recorded entry as a layout constraint rather than a foundation detail.
Do I need a permit to drill?
Yes, where the work will enter or disturb coal seams, mine workings or mine entries. A permit from the mining authority is required before drilling, grouting or excavating into those features, and it takes time to obtain. Programme it alongside the site investigation rather than discovering it the week the rig is booked.
Does a referral area stop development?
No. Most sites in development high risk areas are developed successfully once the risk is understood and treated. What the designation does is add a report, a consultation, sometimes a permit and often a grouting cost. The schemes that suffer are the ones that discover a shaft after the layout and the land price are fixed.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.