Big Pit National Coal Museum (Welsh: Pwll Mawr Amgueddfa Lofaol Cymru) is an industrial heritage museum in Blaenavon, Torfaen, South Wales. A working coal mine from 1860 to 1980, it was opened to the public in 1983 under the auspices of the National Museum of Wales. The site is dedicated to operational preservation of the Welsh heritage of coal mining, which took place during the Industrial revolution.