Mining in Wales provided a significant source of income to the economy of Wales throughout the nineteenth century and early to mid twentieth century. It was key to the Industrial Revolution in Wales, and to the whole of Great Britain.
Wales was famous for its coal mining, in the Rhondda Valley, the South Wales Valleys and throughout the South Wales coalfield and by 1913 Barry had become the largest coal exporting port in the world, with Cardiff as second, as coal was transported down by rail. Northeast Wales also had its own coalfield and Tower Colliery (closed January 2008) near Hirwaun is regarded by many as the oldest open coal mine and one of the largest in the world. Welsh coal was regarded as some of the best burning and highest quality material for power generation, railroading, shipping, and was sold for higher prices. Wales has also had a significant history of mining for slate, gold and various metal ores, making it one of the most materially rich plains in the world.