Documents for a scheme in a coal mining reporting area

If your site sits in a Development High Risk Area, the council will not validate the application without a coal mining risk assessment. That single document sits at the front of the coal mining reporting area documents list, and everything else follows from what it finds: intrusive investigation, a permit before any drill touches a seam, foundation design that spans or avoids shallow workings, and gas protection where the ground has a pathway to the building.

The national coal mining body, now the Mining Remediation Authority and previously the Coal Authority, is a statutory consultee for development in those areas, so the report is read by people who know the ground.

Checking whether the site is in a reporting area

Two categories apply across the coalfields. Development High Risk Areas cover land where recorded mining features could affect surface stability, and they trigger the assessment requirement. Development Low Risk Areas cover the rest of the coalfield, where standing advice applies and no assessment is normally needed.

The interactive map published by the Authority shows the boundary, and it is postcode searchable. Check it before you buy, not after, because the boundary does not follow property lines and neighbouring plots can sit on either side of it.

Recorded features include mine entries such as shafts and adits, shallow coal workings, coal outcrops, recorded surface hazards, mine gas emissions, and past claims for subsidence damage.

Past claims matter as well as physical features. A property with a subsidence claim history attracts closer scrutiny from both the consultee and any future lender, and the claim file often contains ground data that saves a borehole.

Obtaining the mining report

The planning report and the conveyancing report are different products, and buying the wrong one wastes a fortnight.

A conveyancing coal mining search tells a purchaser whether the property is affected by past or present mining and whether there is a subsidence claim history. A mining report for development purposes provides the underlying data a specialist needs: recorded workings and their depths, mine entry locations and details, geological information and past treatment records.

Order the development report at the earliest feasible point, because it sets the scope of everything downstream. Where the data shows unrecorded workings are likely, budget for intrusive investigation from the outset rather than treating it as a contingency.

When a mining risk assessment is required

In a Development High Risk Area, the assessment accompanies the application. It has to be prepared by a suitably qualified and experienced person, typically a chartered geotechnical or engineering geologist, and it is not a PlanScope report type.

Content that satisfies the consultee:

• a factual summary of the mining data, including workings, seams, depths and dates
• an interpretation of what those features mean for the proposed layout and foundation loads
• identification of mine entries within and near the site, with their zones of influence plotted on the layout
• a view on the likelihood of unrecorded shallow workings
• the proposed investigation, or the remediation where investigation has already been done
• confirmation that any permits needed have been identified

What gets objections is an assessment that recites the data and stops. The consultee wants conclusions about your scheme, on your drawings.

One honest caveat. The records are only as good as the era that made them, and pre-nationalisation workings from before 1947 are patchily documented. An assessment that concludes there are no recorded workings has said something narrower than it appears, and an experienced consultee reads it that way.

Intrusive investigation for shallow workings

Where workings lie within the zone of influence of the proposed foundations, rotary open hole and cored boreholes establish whether voids remain open, partially collapsed or fully consolidated.

The results drive treatment. Drilling and grouting to fill voids is the common approach, designed to a specification with verification holes afterwards. Dynamic compaction or excavate and replace may suit very shallow workings. Piling through to competent strata is an alternative where grouting would be disproportionate, though it brings its own permit question.

Grouting is not a one-visit exercise either. Verification drilling after treatment is normal, and the specification should say what grout take triggers further holes, so the contractor is not deciding that on site.

Sequence the work with the geotechnical assessment so that one ground investigation answers the mining, contamination and foundation questions together. Separate investigations for each discipline cost more and take longer.

Mine entries and their standoff distances

Shafts and adits are treated differently from workings, and they are the feature most likely to stop a layout.

Each recorded entry carries a zone of influence around it, derived from its depth, diameter and treatment history, within which development is restricted. Locating the entry precisely usually needs a site investigation of its own, because historic positions were recorded to the accuracy of the day and can be out by tens of metres.

Where an entry is found, treatment typically means excavating to sound strata, capping with a reinforced concrete slab designed to span the shaft, and providing a permanent vent. The capped entry is then kept clear of buildings, and gardens or parking are put over it instead. Plan the layout with that in mind rather than discovering it after the masterplan is fixed.

Permits for entering coal seams

This is the step that catches self-builders. Written permission from the Authority is required before entering or disturbing coal, mine workings or mine entries, because those interests are vested in it under the Coal Industry Act 1994.

That covers site investigation boreholes intersecting a seam, grouting works, piling into or through workings, and excavation encountering coal. Applications take time, and starting work without permission is trespass against the Authority's property as well as a source of risk.

Build the permit into the programme alongside the planning timetable. On a small site the permit and the investigation together can take longer than determination of the application.

Foundation design and gas protection

Treatment and foundations have to be designed together. Where workings have been grouted, conventional foundations may be acceptable. Where they have not, reinforced ground beams and rafts able to span a potential void, or piles to rockhead, become the design.

Mine gas is the parallel issue. Carbon dioxide and methane migrate along old workings and unsealed entries, so a gas risk assessment with monitoring rounds may be needed, and the protection measures specified to the relevant British Standard for gas resistant construction. Contamination from spoil, former coking and washery sites often sits on the same land, so run the contaminated land assessment from the same investigation.

Both pieces of work must be prepared by suitably qualified and experienced people. A draft is a starting point for that specialist, never a replacement for one.

Enter your postcode on PlanScope to see which reports a coalfield site is likely to need, or browse all 66 report types before commissioning the ground investigation.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. Organisation names and guidance change, so verify the current requirements at the time you apply. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.