Coal mining reporting areas and the referral process
A plot in a Development High Risk Area needs a Coal Mining Risk Assessment with the application. Here is how to check the mapping, what the report must say, and where the money goes.
If your plot sits in a coal mining reporting area, and more precisely in what is mapped as a Development High Risk Area, the council will expect a Coal Mining Risk Assessment with the planning application and will consult the national coal authority before deciding. The assessment is a desk study first. It reads the mine abandonment plans for your site, works out whether shafts, adits or shallow workings are likely to be under it, and says what intrusive investigation is needed before anything is built.
Self-builders often meet this for the first time at validation, when the application is held because a document nobody mentioned is missing. Twenty minutes on the public mapping at the offer stage avoids that.
What a development high risk area is
Former coal workings run under a large part of the housing stock in the English coalfields, and the risk is not spread evenly. The coal authority maps areas where recorded mining legacy features could affect the stability or safety of new development: mine entries such as shafts and adits, workings at shallow depth, recorded fissures and areas of past treatment.
Inside a Development High Risk Area, the expectation is a site specific assessment. Outside it, in what is described as a low risk area, standing advice normally applies and no assessment is needed, although the ground may still be affected by other mineral workings such as ironstone, clay or limestone, which the coal mapping does not show.
The distinction that catches people is between the report you buy when you purchase a house and the report you need for planning. A coal mining search obtained through a conveyancer answers questions about subsidence claims and liability. It is not a Coal Mining Risk Assessment and councils will not accept it as one.
Checking the interactive mapping
The coal authority publishes an interactive map viewer as a free public tool, and the British Geological Survey holds borehole and mine plan records alongside it.
Do three checks before you commit to a site.
- Search the address on the interactive viewer and record whether it falls in a Development High Risk Area, capturing the plan with a date on it.
- Look for recorded mine entries within about 50 metres of the plot boundary, because a shaft just outside your land can still impose a no build zone inside it.
- Note any surface hazard, past treatment or reported subsidence flagged for the immediate area.
Then read the answer against your layout. A recorded shaft under the footprint of a proposed dwelling is not a reason to walk away, but it changes the design: the building moves, the garden absorbs the influence zone, and the cost of treatment enters the appraisal. Constraint checks of this kind belong in the pre-offer routine set out in checking a site for constraints before you make an offer.
When a coal mining risk assessment is required
The trigger is location plus the type of development. Within a Development High Risk Area, an assessment is normally expected for new buildings, extensions with foundations, and works involving ground disturbance. Minor works such as a fence or a small non-habitable outbuilding are usually outside it, but local validation lists differ and the council's own checklist is the authority on what it will accept.
A workable assessment contains:
- A description of the site and the proposed development, with levels
- The mining history, taken from abandonment plans and records rather than from a general map
- Seam names, depths and inclination, with an opinion on the likelihood of unrecorded shallow workings
- Recorded mine entries, their positions, their accuracy tolerance and any treatment record
- An assessment of the risk each feature presents to the proposal
- Recommendations for intrusive investigation, with a scope
- Conclusions on whether the development can proceed safely and what is needed to make it so
The recommendations section is the one officers read. A report that concludes "further investigation is recommended" without saying what, where and to what depth invites a condition you will have to discharge later anyway.
This is engineering work. Councils expect it from someone with relevant experience in mining legacy ground conditions, and the interaction with foundation design means it usually sits alongside a Geotechnical Assessment rather than replacing one. PlanScope can draft the reporting structure, and professional input on ground stability is needed either way.
Shafts, adits and shallow workings
Three legacy features behave differently and the assessment should treat them separately.
A shaft is a vertical opening, often capped at some point in the past with timber, brick or a slab that has no design life. Recorded positions carry a tolerance, sometimes tens of metres on older plans, so the investigation looks for the shaft rather than assuming the mapped point. Once found, treatment is normally excavation to sound rock, a reinforced concrete cap and a recorded position, with a stand-off zone around it that stays free of buildings.
An adit is a near horizontal entry driven into a hillside. Adits show up on sloping sites and are frequently unrecorded, and they can carry water, which matters for drainage design as well as stability.
Shallow workings are the widespread case. Where a seam has been worked at shallow depth, the ground above may contain voids or loosened rock that will collapse under load. Treatment is usually drilling and grouting on a grid, or foundations designed to span or transfer load below the affected zone. The extent of grouting is the cost variable, because it is priced by volume and the volume is only known once the drilling starts.
The consultation response and typical conditions
The council consults the coal authority, which comments on the adequacy of the assessment rather than on the planning merits. Three outcomes are common: no objection, no objection subject to a condition, or an objection because the assessment does not address the recorded features.
Conditions usually follow a familiar pattern. A site investigation scheme to be submitted and approved before work starts. Remediation works to be carried out in accordance with the approved scheme. A verification report confirming what was done, submitted before occupation. Where a mine entry is present, a condition fixing the no build zone.
Read the wording for its trigger. A condition requiring intrusive investigation before any development begins blocks the investigation itself if it is drafted carelessly, and that is worth raising with the officer before the decision is issued.
Permits to enter or disturb coal
Coal in the ground is owned nationally, and drilling into or through a coal seam, a mine entry or old workings needs a permit from the coal authority. Grouting, probing and shaft treatment all fall within it.
Two practical points. Apply early, because the permit is a separate process from planning and the site investigation contractor will not mobilise without it. And do not assume the planning condition and the permit are the same thing satisfied by the same document: the council wants to know the ground is safe, and the permit exists to protect the national coal interest and third parties from uncontrolled entry into workings.
Costs and programme
A desk based Coal Mining Risk Assessment for a single plot is a modest piece of work, at the lower end of technical report costs, and can usually be turned round in a fortnight once the records are obtained.
The money is in what follows. Intrusive investigation with a rig, grouting to treat shallow workings, and shaft location and capping are all priced by the day or by volume, and the range between a site that needs six boreholes and one that needs a grout curtain is wide. That is the honest uncertainty in a mining legacy site, and no desk study removes it. Build a contingency for treatment into the appraisal, and get the investigation done before the foundation design is fixed rather than after.
Illustrative example: a two plot infill in a former coalfield village sits in a Development High Risk Area with a shaft recorded 18 metres beyond the rear boundary and a seam worked at about 25 metres depth. The desk study recommends four boreholes on the building footprints and a search for the shaft, which is found within tolerance and outside the site. Grouting is limited to one plot. Figures here are illustrative.
Where the application pack is coming together, PlanScope drafts the supporting statements a coalfield site needs, flagging missing facts rather than inventing them, and stability work needs a suitably qualified engineer. Enter your postcode on PlanScope to see which reports the plot is likely to need.
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.
Frequently asked questions
Is a conveyancing coal mining search the same as a risk assessment?
No, and councils will not accept one in place of the other. A coal mining search bought through a conveyancer answers questions about subsidence claims and liability for an existing property. A Coal Mining Risk Assessment is a site specific desk study of mine records against your proposed development, with recommendations for intrusive investigation.
How do I find out whether my site is in a high risk area?
Use the coal authority's free interactive map viewer, search the address, and capture a dated plan showing whether the site falls within a Development High Risk Area. Check for recorded mine entries within about 50 metres of the boundary, because a shaft on neighbouring land can still impose a no build zone inside yours.
What does the assessment have to contain?
A site and development description with levels, the mining history taken from abandonment plans, seam names, depths and inclination, an opinion on unrecorded shallow workings, recorded mine entries with position tolerances and treatment records, a risk assessment for each feature, and a specific scope for intrusive investigation.
Do I need a permit to drill into old workings?
Yes. Coal in the ground is nationally owned, so drilling into or through a coal seam, a mine entry or old workings needs a permit from the coal authority, and that covers probing, grouting and shaft treatment. Apply early, because it is separate from planning and contractors will not mobilise without it.
What will the coal mining condition require?
Typically a site investigation scheme approved before work starts, remediation carried out in accordance with the approved scheme, and a verification report before occupation, plus a no build zone where a mine entry is present. Check the trigger wording, because a condition drafted to bite before any development can accidentally block the investigation itself.
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.