Selling a House in a Mining Subsidence Area: A Seller's Guide

If your property sits in a former coal mining area \u2014 or has been affected by any kind of mining subsidence \u2014 you may be concerned about what this means for your sale. Mining subsidence is a distinct issue from the clay shrinkage subsidence that affects much of southern England, and it comes with its own legal framework, search requirements, and disclosure obligations.

The good news is that millions of homes across England and Wales sit within coal mining reporting areas and are bought and sold at normal market prices every day. This guide explains the process, the searches your buyer will need, your obligations as a seller, and what to do if your property has an active or historic mining subsidence claim.

What is mining subsidence?

Mining subsidence occurs when the ground above former mine workings shifts or settles, causing movement at the surface. When coal or other minerals are extracted from underground seams, voids are left behind. Over time, the rock and soil above these voids can collapse or compress, causing the ground level to drop. This downward movement can damage buildings, roads, drains, and other structures on the surface.

Unlike general subsidence caused by clay shrinkage or tree roots, mining subsidence has a specific legal framework governing responsibility and remediation. The cause is human activity rather than natural ground conditions, and the Coal Authority bears statutory responsibility for managing its consequences.

Types of mining that cause subsidence

Coal mining is the most widespread cause of mining subsidence in England and Wales, but it is not the only one. The main types of mining that can affect residential properties include:

• Deep coal mining. Underground extraction through shafts and tunnels. Subsidence can occur decades after mining ceases as remaining pillars and supports deteriorate. This is the most common type and is covered by the Coal Authority's CON29M search.
• Opencast (surface) coal mining. Extraction by removing overlying soil and rock. Subsidence risks relate to the quality of backfill after extraction. Opencast sites are recorded by the Coal Authority.
• Brine extraction. Pumping brine (salt dissolved in water) from underground deposits, particularly in Cheshire. Wild brine pumping in the 19th and early 20th centuries caused catastrophic subsidence in towns such as Northwich and Middlewich. Modern controlled extraction is less damaging but residual risks remain.
• Tin and copper mining. Extensive shallow workings across Cornwall and Devon left networks of shafts and adits (horizontal tunnels). These are not covered by the CON29M search and require a separate specialist mining report.
• Lead mining. Historic lead mining in the Peak District, Yorkshire Dales, and North Wales created shallow workings that can affect surface stability. Again, a specialist non-coal mining search is needed.

Our guide on coal mining search areas in the UK explains where these different mining types are concentrated and how to check whether your property is affected.

The Coal Authority and its role

The Coal Authority is a non-departmental public body sponsored by the Department for Energy Security and Net Zero. It manages the legacy of coal mining across Great Britain, including responsibility for approximately 42,000 recorded coal mine entries (shafts and adits) and vast areas of former underground workings.

For property sellers, the Coal Authority is relevant in three key ways:

1. It defines coal mining reporting areas. These are the geographical boundaries within which a CON29M coal mining search is required during conveyancing. According to the Coal Authority, approximately 42% of properties in England fall within a reporting area.
2. It produces the CON29M search report. This is the official coal mining search that the buyer's solicitor orders as part of standard property searches. The report reveals whether there are mine workings, mine entries, subsidence claims, or other coal mining features affecting the property.
3. It handles mining subsidence damage claims. Under the Coal Mining Subsidence Act 1991, the Coal Authority has a statutory obligation to remediate damage to residential properties caused by coal mining subsidence, at no cost to the property owner.

The CON29M coal mining search

The CON29M is the standard coal mining search used in residential conveyancing. It is produced exclusively by the Coal Authority and cannot be obtained from any other source. The search typically costs between \u00a330 and \u00a350 and results are usually returned within 24 to 48 hours.

The CON29M report covers a comprehensive list of mining-related issues:

• Whether past underground mining has taken place beneath or near the property
• Whether any mine entries (shafts or adits) are recorded within or close to the property boundary
• Whether any coal mining subsidence claims have been made for the property
• Whether the property is in an area of probable shallow coal workings
• Whether opencast mining has taken place on or near the site
• Whether there are any Coal Authority licensing, permit, or notice issues
• Whether mine gas has been reported in the area

For sellers, understanding what the CON29M will reveal about your property allows you to prepare. If you know there has been a historic subsidence claim, for instance, you can gather the relevant documentation before the buyer's solicitor raises enquiries about it.

The Coal Mining Subsidence Act 1991

The Coal Mining Subsidence Act 1991 is the primary legislation governing liability for coal mining subsidence damage in Great Britain. It replaced earlier legislation and established a clear statutory framework that continues to protect homeowners today.

Key provisions of the Act include:

• Duty to remediate. The Coal Authority must take steps to remediate damage to dwelling houses caused by coal mining subsidence, either by carrying out repairs or paying compensation.
• Damage notice. Property owners can submit a damage notice to the Coal Authority at any time. There is no time limit for making a claim.
• Scope of cover. The Act covers the cost of repairs to the property structure, boundary walls, paths, driveways, and in some cases underground services such as drains and sewers. Emergency works where the property is dangerous or uninhabitable are also covered.
• Temporary accommodation. Where a property is rendered uninhabitable, the Coal Authority may contribute towards the cost of temporary alternative accommodation while repairs are carried out.
• Stabilisation. Where the risk of future subsidence is significant, the Coal Authority may carry out stabilisation works such as grouting mine voids or treating shallow workings to prevent further movement.

This statutory protection is a significant advantage for properties in coal mining areas compared with properties affected by other types of subsidence. When a property suffers clay shrinkage subsidence, the homeowner must claim on their buildings insurance and bear the cost of any excess. With coal mining subsidence, the Coal Authority covers the cost of remediation under a statutory duty.

Submitting a damage claim to the Coal Authority

If your property has suffered damage that you believe is caused by coal mining subsidence, you should submit a damage notice to the Coal Authority. The process works as follows:

1. Report the damage. Contact the Coal Authority by telephone or through their online portal. You will need to describe the damage, provide photographs, and give the property address and your ownership details.
2. Investigation. The Coal Authority will appoint a surveyor to inspect the property and assess whether the damage is consistent with coal mining subsidence. This may involve reviewing mining records, examining crack patterns, and in some cases installing monitoring equipment.
3. Decision. If the Coal Authority accepts the claim, it will propose a scheme of remedial works or offer compensation. If the claim is rejected \u2014 for example, because the damage is attributed to clay shrinkage rather than mining \u2014 you can appeal the decision.
4. Remediation. Accepted claims are remediated at the Coal Authority's expense. This may involve structural repairs, stabilisation of mine workings beneath the property, or in severe cases, acquisition of the property at market value.

If you are planning to sell, it is better to report suspected mining subsidence damage before listing. Having a claim in progress \u2014 or ideally resolved \u2014 gives buyers confidence that the issue is being managed through the proper statutory process rather than being concealed.

Disclosure on the TA6 form

As a seller, you are legally required to disclose known mining subsidence on your TA6 Property Information Form. Section 7.4 asks whether the property has been affected by subsidence, landslip, or ground heave. This includes mining subsidence.

You should disclose:

• Any current or historic Coal Authority damage claim for the property
• Any visible cracking or structural movement you believe may be related to mining
• Any stabilisation or remedial works carried out by the Coal Authority or a previous owner
• Any correspondence with the Coal Authority about the property

Our guide on what to disclose when selling covers your broader obligations. Being thorough in your disclosure protects you from post-completion claims and builds trust with the buyer. Concealing known mining subsidence could constitute fraudulent misrepresentation under the Misrepresentation Act 1967.

Impact on surveys and valuations

When a property is in a coal mining area, the buyer's surveyor will pay close attention to signs of structural movement. Mining subsidence often produces a characteristic pattern of damage that is distinct from clay shrinkage subsidence:

The surveyor's report may recommend further investigation if signs of movement are found, such as a specialist structural engineer's assessment or a review of the Coal Authority records. For mortgage valuations, the valuer will note whether the CON29M search is clear or whether any issues have been flagged.

Properties with a fully resolved mining subsidence claim and supporting documentation typically receive a normal valuation. Properties with unresolved claims or evidence of ongoing movement may receive a reduced or nil valuation, which will affect the buyer's ability to secure a mortgage.

Mortgage lender attitudes to mining areas

Most mainstream mortgage lenders will lend on properties in coal mining areas without difficulty, provided the CON29M search does not reveal a specific unresolved problem. The UK Finance Mortgage Lenders' Handbook sets out each lender's individual requirements, and the buyer's solicitor will check these as part of the conveyancing process.

Lender attitudes typically depend on what the CON29M reveals:

Where a lender declines because of a mining-related issue, the buyer may need to approach a specialist lender or purchase with cash. As a seller, you can help by ensuring any resolvable issues \u2014 such as submitting a damage notice to the Coal Authority or obtaining confirmation that historic claims have been closed \u2014 are dealt with before or during the sale.

Insurance and mining subsidence

The insurance position for mining subsidence is different from other forms of subsidence. Because the Coal Mining Subsidence Act 1991 places responsibility for coal mining subsidence damage on the Coal Authority, standard buildings insurance policies typically exclude mining subsidence from their cover. This is not a gap in protection \u2014 it reflects the fact that the Coal Authority, not the insurer, is the responsible party.

However, buildings insurance remains important for:

• Subsidence from non-mining causes (clay shrinkage, tree roots, defective drainage) which is covered by standard buildings insurance
• Properties affected by non-coal mining (tin, lead, brine) where there is no equivalent statutory compensation scheme
• All other standard perils such as fire, flood, and storm damage

Buyers purchasing a property in a coal mining area should ensure their buildings insurance is in place and understand that mining subsidence damage is handled through the Coal Authority rather than their insurer. As a seller, being able to explain this distinction can help address buyer concerns and prevent unnecessary anxiety during the transaction.

Affected areas across the UK

Coal mining reporting areas cover substantial parts of England and Wales. The Coal Authority's interactive map shows the precise boundaries, but the main coalfield regions include:

• North East England \u2014 Northumberland and County Durham, including Newcastle, Sunderland, and the former pit villages of the Durham coalfield
• Yorkshire \u2014 The South Yorkshire and West Yorkshire coalfields covering areas around Barnsley, Doncaster, Wakefield, and Leeds
• East Midlands \u2014 The Nottinghamshire and Derbyshire coalfield extending into parts of Leicestershire
• West Midlands \u2014 The Black Country (Dudley, Walsall, Sandwell) and parts of Staffordshire
• North West England \u2014 The Lancashire coalfield (Wigan, St Helens, Bolton) and the Cumberland coalfield in west Cumbria
• South Wales \u2014 The South Wales Valleys from Pontypool to Llanelli, one of the most extensively mined areas in Britain
• Kent \u2014 A smaller coalfield around Dover, Deal, and Aylesham where mining took place from the early 1900s until 1989

Non-coal mining areas with subsidence risk include the tin and copper mining districts of Cornwall and Devon, the brine extraction areas of Cheshire, the lead mining areas of the Peak District and Yorkshire Dales, and former iron ore mining areas in Cumbria and Cleveland. These are not covered by the CON29M search and require separate investigation. Our guide on coal mining search areas provides a detailed regional breakdown.

Stabilisation and remediation

Where the Coal Authority identifies a risk of future subsidence, it may carry out stabilisation works to prevent damage occurring. Common stabilisation techniques include:

• Grouting. Injecting cementitious grout into mine voids to fill them and prevent collapse. This is the most common technique for treating shallow workings beneath residential properties.
• Crown hole treatment. Crown holes are localised collapses at the surface where shallow workings have breached through. The Coal Authority treats these by excavating the affected area and filling it with engineered material.
• Mine entry capping. Disused mine shafts and adits are sealed with reinforced concrete caps or grilles to prevent collapse and restrict access. The Coal Authority maintains a register of treated mine entries.

If stabilisation has been carried out on or near your property, the Coal Authority will have records confirming the work. These records are valuable documentation when selling and should be provided to the buyer's solicitor alongside your other conveyancing paperwork.

Relationship between mining subsidence and general subsidence

Mining subsidence and general subsidence (caused by clay shrinkage, tree roots, or drainage failure) are distinct issues with different legal and insurance frameworks. However, they can coexist. A property in a clay-rich area that also sits above former mine workings could theoretically be affected by both.

The key differences are:

• Liability. Mining subsidence is the Coal Authority's responsibility under the 1991 Act. General subsidence is the homeowner's responsibility, typically managed through buildings insurance.
• Searches. Mining subsidence is identified through the CON29M search. General subsidence risk is identified through environmental searches and ground stability assessments.
• Disclosure. Both must be disclosed on the TA6 form under Section 7.4 if you are aware of them.

Our comprehensive guide on selling a house with subsidence covers general subsidence in detail, including clay shrinkage, underpinning, monitoring, and insurance. If your property is affected by both mining and non-mining subsidence, you will need to address each issue separately through the appropriate channel.

Practical steps for sellers in mining areas

1. Check the Coal Authority's interactive map. Confirm whether your property is in a coal mining reporting area. This is free to check online at coalauthority.gov.uk.
2. Review your own CON29M results. If you purchased the property through a solicitor, your original conveyancing file should contain a CON29M search. Review it to understand what was known at the time of your purchase.
3. Report any suspected damage. If you believe your property has suffered mining subsidence damage, submit a damage notice to the Coal Authority before listing. Having a claim in progress or resolved is far better than leaving the buyer to discover the damage through their survey.
4. Complete your TA6 form thoroughly. Disclose all known mining-related issues in Section 7.4. Attach copies of any Coal Authority correspondence, claim records, or stabilisation certificates.
5. Gather documentation. Collect any Coal Authority correspondence, completed claim records, stabilisation certificates, and structural reports. Having these ready before enquiries are raised can prevent weeks of delay.
6. Brief your solicitor. Ensure your conveyancer understands the mining history of the property and has the documentation to respond to the buyer's enquiries promptly.

Sources and further reading

• Coal Authority \u2014 Interactive map of coal mining reporting areas, CON29M search information, and subsidence damage claims process: coalauthority.gov.uk
• Coal Mining Subsidence Act 1991 \u2014 Full text of the legislation: legislation.gov.uk/ukpga/1991/45/contents
• British Geological Survey (BGS) \u2014 Mining hazards and ground stability data, including non-coal mining areas: bgs.ac.uk
• UK Finance \u2014 Mortgage Lenders' Handbook, including individual lender requirements for properties in mining areas: lendershandbook.ukfinance.org.uk
• Law Society \u2014 TA6 Property Information Form guidance notes and CON29M search guidance: lawsociety.org.uk
• Royal Institution of Chartered Surveyors (RICS) \u2014 Guidance on surveying properties affected by mining subsidence: rics.org

Frequently asked questions