Mine entries, permits and coalfield planning conditions

On a site inside a development high risk area, a coal mining risk assessment gets you through validation. What determines the programme is everything that happens afterwards: the standoff around any recorded mine entry, the permit you need before a drilling rig touches coal, the intrusive investigation, the remediation and the verification report the council wants before it will discharge the condition.

Two consent regimes run in parallel on these sites, and only one of them is the planning system.

What a development high risk area is

The coalfield authority, established under the Coal Industry Act 1994 and now operating as the Mining Remediation Authority, maintains the records of past coal mining across Britain and publishes interactive mapping that divides the coalfield into development high risk areas and development low risk areas.

A high risk area is one where the records indicate features capable of affecting surface stability or ground conditions: recorded or probable shallow workings, mine entries such as shafts and adits, mine gas, past surface mining, spoil, mine water or faulting associated with workings. Being in a high risk area does not mean the site is unbuildable. It means the risk has to be assessed and, where present, designed for.

The authority is a consultee on development in these areas, and coalfield councils carry a coal mining risk assessment on their local validation lists. The general position on referral areas and the report itself is covered in our note on Coal Authority referral areas and the mining risk report. What follows is what happens after that report is written.

Checking the mapping before you buy

Do this at option stage, not at design stage.

The published interactive mapping shows whether the site falls in a high risk area. A separate coal mining report, ordered from the authority, gives the site-specific record including mine entries within a defined radius, recorded workings, past claims and any current licensing. A conveyancing coal mining search is a different product from the planning evidence and does not substitute for it.

Cross-check against the British Geological Survey mapping for the coal measures and against historic Ordnance Survey editions, which often show shaft positions, pit head structures and spoil that the record has lost. Old maps have found more forgotten shafts than any database.

Mine entries and standoff distances

A recorded mine entry is the constraint that reshapes layouts. Shafts were capped to the standard of their day, which in the nineteenth century often meant timber and rubble, and a cap can fail decades later.

The authority's guidance establishes a zone of influence around a mine entry within which no building should be placed, derived from the shaft diameter and the depth of superficial deposits over rockhead rather than from a single fixed distance. Within that zone the land is normally kept as open space, parking or landscape, and the entry is located precisely, exposed, examined and capped to a modern standard before anything is built near it.

Positional accuracy is the practical problem. Recorded positions carry an error margin that can be tens of metres, so the search for the entry is itself a site operation with its own cost and programme. Plan the layout with the flexibility to absorb a shaft that turns out to be somewhere other than the plan says.

Intrusive investigation and treatment

The desk-based assessment identifies the risk. Intrusive investigation confirms it.

That usually means rotary open hole and cored boreholes proving the depth to and condition of the coal seams, logging voids and broken ground, gas monitoring standpipes installed and monitored over a period that captures falling atmospheric pressure, and where necessary probe drilling on a grid across the footprint. Design the investigation to answer the questions the assessment raised rather than to a standard specification.

Treatment, where it is needed, is normally drilling and grouting of shallow workings across the building footprint plus a margin, capping of mine entries, or a foundation solution that spans or avoids the risk. Gas protection measures follow the published British Standard approach to characteristic situations, with the design based on monitored data rather than an assumed classification.

Where spoil or former surface plant is present, contamination is usually in play as well, and the ground investigation should be scoped to serve both purposes in a single round of drilling. A Contaminated Land Assessment and the mining work share boreholes, laboratories and a site visit, and splitting them across two contractors wastes most of that. Both require suitably qualified and experienced authors.

Permits for entering coal seams

This is the regime people miss until the rig is booked.

Property in unworked coal and in coal mines vests in the authority, and its written permission is required before anyone enters or disturbs them. That covers drilling a borehole that will intersect a coal seam or a mine working, grouting into workings, piling into or through workings, and remediation of a mine entry.

Apply early. The permit is a separate application to a separate body with its own timescale, and it is not granted by the planning permission or the building control approval. A ground investigation contractor who says the permit is in hand should be asked to produce the reference.

There is also a separate licensing regime for coal extraction, which is what applies if the scheme would remove coal as part of the works rather than merely disturb it.

Conditions and how they discharge

Coalfield councils use a predictable condition set. A typical permission requires the intrusive site investigation to be carried out and its results submitted before development begins, then a remediation scheme to be approved, then the remediation to be implemented, then a verification report to be submitted and approved before occupation.

Three practical points.

First, the wording usually catches any groundwork, so the site investigation itself has to be planned as a distinct exercise before the main contractor mobilises. Second, the verification report is the document that closes the file, and it needs the drilling records, the grout takes, the as-built positions and the gas monitoring data presented against the approved scheme rather than as an appendix of raw logs. Third, the authority's comments on the discharge submission carry weight with the case officer, so send it to both.

Where the risk assessment concludes that foundation design must respond to the ground conditions, the structural and geotechnical work has to match. A Geotechnical Assessment prepared to Eurocode 7 and a mining report that assume different ground models is a combination that stops a condition discharge in its tracks.

A final honest note. A substantial proportion of high risk area sites turn out, after investigation, to need nothing more than a confirmatory report. The cost of finding that out is real, and it belongs in the appraisal at acquisition rather than arriving as a surprise in the first year of the programme.

Enter your postcode on PlanScope to see which supporting documents a site in a coalfield area is likely to need.

This is general guidance, not legal advice. For specialist technical reports, qualified professional input may be required, and ground investigation and remediation must be designed by suitably qualified and experienced persons. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.