A colliery at Hafodyrynys was worked briefly in the late 1870s, and a new pit was sunk there between 1911 and 1914. Following nationalization, this was chosen as one of the south Wales collieries for massive redevelopment. It was linked underground with three others in a £5.5 million investment scheme begun in 1954. The new colliery buildings and washery were designed with modern buildings and equipment for maximum efficiency. Architecturally, they were influenced by the functionalism of pre-war collieries in Germany designed by the Bauhaus architect Peter Behrens, by the sinuous forms of the Festival of Britain, and possibly by the nearby Brynmawr Rubber Factory. All the buildings had reinforced concrete frames filled by brick or glass panels and flat, curved or wave form concrete roofs. Washery plants were key elements in post-war efficiency improvements, as only half of British coal output was being washed in 1945. The washery at Hafodyrynys contained equipment for extracting coal dust from slurry and drying the remaining waste before tipping: processes which were rare before the 1950s. It was built entirely of reinforced concrete with continuous glazed panels. The colliery closed in 1966 and the site was cleared in 1985, but the slimes thickener at the washery was retained at the request of Sir Richard Hanbury-Tenison of Pontypool Park Estate, to which the site reverted. Plans were drawn up at the time to adapt the building as a restaurant. Its futuristic use of reinforced concrete and the splendid isolation in which it now stands have made it a well-known landmark.
A.P. Wakelin, 26 July 2006