Big Pit: National Coal Museum, an operating underground heritage attraction within the Blaenavon UNESCO World Heritage Site, open to the public since 1983.
Big Pit National Coal Museum is a former deep coal mine in Blaenavon, Torfaen, now operating as a publicly accessible heritage museum and part of the Blaenavon Industrial Landscape, a UNESCO World Heritage Site. The site occupies the location of an earlier iron mine active around 1810. The Big Pit shaft was sunk on the site of an earlier working known as Kearsley's Pit around 1860, deepened in 1880 to its present depth of approximately 300 feet (90 metres), and first described in an inspector's report of 1881.
It was the most important colliery in Blaenavon, employing around 1,300 men in the early 1920s. Pithead baths were installed in 1939. On nationalisation in 1947 the National Coal Board took over the mine from Blaenavon Co. Ltd. By 1973 windings at Big Pit had ceased as coal was extracted via an associated drift mine.
The pit closed on 2 February 1980. It reopened as a museum in April 1983 under the Big Pit (Blaenavon) Trust and was incorporated into National Museum Wales on 1 February 2001. The Blaenavon Industrial Landscape, including Big Pit, was inscribed as a UNESCO World Heritage Site in 2000.
The museum won the Gulbenkian Prize in 2005.
The earliest industrial activity at the Big Pit site predates the coal mine. An iron mine, driven into the side of the mountain not far from the surface to exploit shallow iron deposits, is recorded around 1810. The level of this iron mine, called Engine Pit Level, can still be seen on the bridge connecting Blaenavon and Garn Road.
Big Pit formed part of a network of coal workings established in the first half of the nineteenth century by the Blaenavon Iron and Coal Company in connection with the development of the Blaenavon Ironworks. The current Big Pit shaft was sunk on the site of an earlier working known as Kearsley's Pit around 1860 to an initial depth of 200 feet. The shaft has an elliptical shape with dimensions of 18 feet by 13 feet, making it the first shaft in Wales large enough to allow two tramways.
It was deepened in 1880 to its present depth of approximately 300 feet (90 metres), becoming the coal-winding shaft on completion. The first mines inspector's report to describe a mine called Big Pit dates from 1881. Big Pit was an amalgamation of several mines including Coity Pits, Dodd's Slope, Coity Level, Blaenavon New Mine, Elled Drift, Forge Pit, Forge Slope, and Forge Level.
The neighbouring Coity shaft was subsequently incorporated and used for ventilation. Other workings including Mine Slope and Forge Level were also incorporated into the site. In 1866 the Brynmawr and Blaenavon Railway opened with access sidings to the mine workings; the line was immediately leased to the London and North Western Railway, enabling coal to be transported directly to the Midlands.
By 1880 the line had extended south to meet the Great Western Railway at Abersychan and Talywain, connecting to Newport Docks for overseas markets. Over its lifetime the workings at Big Pit exploited nine different coal seams and produced first-class steam coal from an area of about twelve square miles, with annual output exceeding 100,000 tonnes. The colliery employed around 1,300 men in the early 1920s, its peak workforce.
Between 1857 and 1880 more than 60 deaths were recorded by mine inspectors in the Blaenavon coal and ironworks. From 1880 regular reports of accidents at the Big Pit are found. In 1891 a boy, Thomas Oliver Jones, was crushed to death in a roof fall.
In 1894 and 1896 two further miners lost their lives in fatal accidents. On 11 December 1908 three men were killed in an explosion caused by a naked light. On 7 April 1913 three men, including a fireman, the face manager, and the under manager, lost their lives in a localised underground fire.
In 1922 the London and North Western Railway was grouped into the London, Midland and Scottish Railway. In 1939 pithead baths were installed at the mine. During the Second World War, surface extraction of coal at Blaenavon began in November 1941 using equipment and men from the Canadian Army.
On nationalisation in 1947 the National Coal Board took over the mine from Blaenavon Co. Ltd, at which time 789 men were employed. By 1966 Big Pit was the only surviving deep mine in the Blaenavon area. By 1970 the workforce numbered only 494, with operations focused solely on the Garw seam at a maximum thickness of only 30 inches.
The National Coal Board agreed the development of a drift mine, and by 1973 windings at Big Pit had ceased, with coal extracted close to the refurbished Black Lion coal washery. The Coity shaft was abandoned and the Big Pit shaft used for upcast air ventilation and emergency extraction. For some years before final closure a working group comprising the National Coal Board, local government, the National Museum, the Welsh Development Agency, and the Welsh Office had been planning a possible heritage conversion.
The pit finally closed on 2 February 1980 with a loss of more than 250 jobs. Torfaen Borough Council purchased the site for £1 and transferred it to a charitable trust, the Big Pit (Blaenavon) Trust. The initial development cost £1.5 million, funded by the Welsh Tourist Board, the European Regional Development Fund, the borough council, and Gwent County Council.
The mine reopened for visitors in April 1983, creating 71 jobs. The pit bank, steel headframe, and tram circuit date from 1921; the electric winding engine dates from 1952; and the fan house from 1910. The Powder House, Saw Mill, Office, Electrical Workshop, Pit Head Building and Headframe, and Miners' Bathhouse were given Grade II listed building status on 2 September 1995.
The Miners' Bathhouse and the Pit Head Building are listed Grade II*. On 1 February 2001 the museum was incorporated into Amgueddfa Cymru – National Museum Wales, initially as the National Mining Museum of Wales and now known as Big Pit: National Coal Museum. The Blaenavon Industrial Landscape, including Big Pit, was inscribed as a UNESCO World Heritage Site in December 2000.
In 2005 the museum won the Gulbenkian Prize. Big Pit is also an Anchor Point of the European Route of Industrial Heritage. The site was redeveloped in 2003 with design work by TACP/Brooke Millar Partnership.
In April 2025 the museum introduced a charge of £8 for pre-booked underground tours, with admission to the rest of the museum remaining free.
