Coal Mining Search in Durham and Northumberland

County Durham's identity is inseparable from coal. For over 200 years, the Durham coalfield powered the industrial revolution, fuelled the Royal Navy, and shaped the towns, villages, and landscapes of the region. At its peak, the coalfield stretched from the Tees to the Tyne, from the Pennine foothills to the North Sea coast. When the coal industry was nationalised in 1947, County Durham had 234 working collieries — more than any other county in England.

That history has a very practical consequence for anyone selling a property in the region today. If your house sits within the Coal Authority's coal mining reporting area — and most of County Durham, Sunderland, South Tyneside, and south-east Northumberland does — your buyer's solicitor will order a CON29M coal mining search as part of the conveyancing process. This guide explains what that search involves, what it might reveal, and how it affects your sale.

The Durham coalfield: a brief history

The Durham coalfield extends across most of County Durham, from the River Tees in the south to the River Tyne in the north. Coal has been mined in the area since at least the 13th century, but large-scale extraction began in the 18th century and intensified through the 19th and early 20th centuries.

Key facts about the Durham coalfield:

• 234 collieries were operational at nationalisation in 1947
• The coalfield produced both coking coal (for steel making) and steam coal (for power generation and shipping)
• Major mining areas included Consett, Stanley, Chester-le-Street, Durham City, Bishop Auckland, Spennymoor, Seaham, Houghton-le-Spring, and Easington
• The last deep mine in County Durham was Wearmouth Colliery in Sunderland, which closed in 1994. The Stadium of Light now stands on the site.
• Both deep mining (shafts descending hundreds of metres) and shallow mining (drifts and bell pits close to the surface) were practised throughout the coalfield

The Northumberland coalfield to the north has a similar history. The coastal strip from Ashington to Blyth and Cramlington was heavily mined, with Ashington once known as the “largest coal mining village in the world.” Ellington Colliery, the last deep mine in Northumberland, closed in 2005.

Which areas require a CON29M mining search?

The Coal Authority maintains a coal mining reporting area map that identifies properties that may be affected by past, present, or future coal mining activity. If your property falls within this area, the buyer's solicitor will order a CON29M search. For general background on when a mining search is needed, see our guide on whether you need a mining search.

In the Durham and Northumberland region, the following areas are within the coal mining reporting area:

County Durham

• Durham City and surrounding villages
• Chester-le-Street, Pelton, and Great Lumley
• Stanley, Annfield Plain, and Consett
• Bishop Auckland, Shildon, and Newton Aycliffe
• Spennymoor, Ferryhill, and Chilton
• Seaham, Easington, and Peterlee
• Crook, Willington, and Tow Law

Sunderland and South Tyneside

• Sunderland city centre and Wearmouth
• Houghton-le-Spring and Hetton-le-Hole
• Washington and Penshaw
• South Shields, Jarrow, and Boldon

Northumberland (south-east)

• Ashington, Newbiggin-by-the-Sea, and Bedlington
• Blyth and Cramlington
• Morpeth (parts) and Pegswood
• Prudhoe and Wylam (along the Tyne valley)

You can check whether your property is within the coal mining reporting area using the Coal Authority's free interactive map on their website. For more detail on the areas across the UK that require mining searches, see our guide to coal mining search areas.

What the CON29M search covers

The CON29M is the official coal mining search form, published by the Law Society and completed by the Coal Authority. It checks the Authority's records for a range of mining-related factors that could affect the property:

What happens if the search reveals issues

A CON29M search result that flags potential issues does not necessarily mean the sale will fail. The response depends on the nature and severity of the findings:

Low-risk findings

If the search shows that past deep mining occurred in the area but there are no records of shallow workings, mine entries, or subsidence claims, this is typical for most Durham properties and is unlikely to cause concern. The buyer's solicitor may note it in their report but it should not delay the transaction.

Moderate-risk findings

If the search reveals recorded past shallow mining or shows that the property is in a Development High Risk Area, the buyer's solicitor and mortgage lender may require further investigation. This could include:

• A coal mining risk assessment from a specialist ground engineering consultant
• A request for the Coal Authority's Consultants Coal Mining Report, which provides more detailed information than the standard CON29M
• Confirmation from the seller about any subsidence issues, repairs, or insurance claims

High-risk findings

If the search reveals a mine shaft or adit within 20 metres of the property, a history of subsidence claims, or evidence of mine gas emissions, the buyer's lender will almost certainly require a full structural survey and possibly a ground investigation before approving the mortgage. In some cases, the lender may decline to lend altogether, though this is relatively rare for established properties that have been standing without issues for decades.

Subsidence in County Durham

Mining subsidence occurs when old mine workings collapse, causing the ground above to settle. The risk of subsidence depends on several factors:

• Depth of mining. Deep mines (over 100 metres) are less likely to cause surface subsidence than shallow workings (under 30 metres). Most modern deep mining subsidence occurred during the mine's operational life and settled within a few years of extraction.
• Mining method. Pillar-and-stall mining (where pillars of coal were left to support the roof) is more common in older Durham mines and can leave voids that collapse unpredictably. Longwall mining (where the entire seam is extracted and the roof is allowed to collapse in a controlled manner) typically causes subsidence during extraction rather than afterwards.
• Time since closure. Most deep mining subsidence in Durham occurred during or within 10 to 15 years of extraction. Properties that have been stable for decades since the mine closed are at low risk of further movement. Shallow workings are the exception — these can collapse many decades after the mine closed.
• Water levels. As groundwater levels rise in abandoned mines, the water can destabilise old workings. This is a particular concern in parts of County Durham where the Coal Authority is monitoring rising mine water levels.

The Coal Authority operates a subsidence claims process for damage caused by coal mining. If your property has suffered mining-related subsidence, you may be eligible to claim for repairs. Importantly, any past claims will appear on the CON29M search result and should be disclosed to the buyer.

Insurance considerations

Standard buildings insurance policies cover subsidence as a general risk, but properties in mining areas may face additional scrutiny from insurers. Key points for sellers:

• If your CON29M search shows no specific risk factors (no shallow mining, no mine entries, no subsidence claims), standard insurance should be available at normal rates
• If there is a history of subsidence claims on the property, some mainstream insurers may exclude mining subsidence or charge a higher premium. Specialist insurers can usually provide cover.
• The buyer's mortgage lender will require buildings insurance to be in place at exchange of contracts. If mining-related issues make it difficult for the buyer to obtain standard insurance, this could delay or prevent the sale.
• Keeping records of any subsidence-related repairs and the outcomes of any Coal Authority claims helps reassure the buyer and their insurer

Cost and timeline of the CON29M search

The practical details of the mining search are straightforward:

The mining search is one of the fastest property searches available. It rarely causes delays to the overall conveyancing timeline, unlike local authority searches which can take weeks depending on the council. For more on search timelines, see our guide on mining searches explained.

What sellers should do

As the seller of a property in County Durham or Northumberland, the mining search is ordered and paid for by the buyer. However, there are steps you can take to ensure it does not cause problems:

1. Know your mining history. Check the Coal Authority's interactive map to see whether your property is in a coal mining reporting area and, if so, whether it is in a Development High Risk Area.
2. Disclose any subsidence issues. If you are aware of past subsidence, mining-related repairs, or Coal Authority claims, disclose these on the TA6 form. Honesty avoids problems later.
3. Gather documentation. If your property has had subsidence work, keep the Coal Authority's completion certificate, details of repairs carried out, and any engineer's reports. Having these ready to share with the buyer's solicitor speeds up the enquiry process.
4. Inform your estate agent. A good local estate agent in Newcastle or Durham will be familiar with mining searches and can set buyer expectations from the outset.
5. Do not panic. Most properties in former mining areas sell without any issues. The CON29M is a routine search and a positive result (showing no specific risks) is the norm for the vast majority of properties.

More mining and property search guides

• Do I Need a Mining Search?
• Coal Mining Search Areas UK
• Subsidence and Selling a Property

Sources

• The Coal Authority — CON29M coal mining search guidance and interactive map (gov.uk/coalauthority)
• Durham Mining Museum — comprehensive records of Durham collieries and mining history
• National Coal Mining Museum for England — historical data on nationalisation and coalfield statistics
• British Geological Survey — shallow coal mining and subsidence risk mapping
• Law Society — CON29M standard coal mining search form
• Coal Authority — Subsidence claims process and guidance
• UK Finance Lenders' Handbook — requirements for properties in mining areas

Frequently asked questions