The Big Pit National Coal Museum is located in Blaenavon, Torfaen, Wales. A working coal mine from 1880 to 1980, the site is now an industrial heritage museum, which has been open to the public since 1983 under the auspices of the National Museum of Wales. The underground tour of the mine is fantastic and guided by former miners, who provide excellent exploration through the mine. Big Pit is located adjacent to the preserved Pontypool and Blaenavon Railway and is part of the Blaenavon Industrial Landscape World Heritage Site.
According to Wikipedia, Big Pit was originally an iron mine, driven into the side of the mountain not far from the surface due to the shallow iron deposits. Historians disagree about when a mine eventually called The Big Pit first began operating, but a mines inspector report of 1881 is the first to describe a mine called the Big Pit due to the elliptical shape of its shaft with dimensions of 18 feet (5.5 metres) by 13 feet (4.0 metres), making it the first mine in Wales large enough to allow two tramways. By 1908, Big Pit provided employment for 1,122 people, and by 1923 at its peak, there were 1,399 men employed. The peak of production was more than 250,000 tons of coal per year. During the height of production, coal from Big Pit was shipped as far as South America, and also to other points worldwide. On nationalisation in 1947, the National Coal Board took over the mine from the Blaenavon Co. Ltd, which employed 789 men. By 1970 the workforce numbered only 494, as operations had focused solely on the Garw seam, with a maximum thickness of only 30 inches (76 cm). Operations at the Big Pit slowly wound down and the pit finally closed on 2 February 1980 with a loss of more than 250 jobs.