Mining in Wales Mining in Wales Mining in Wales provided a significant source of income to the economy of Wales throughout the nineteenth century and early twentieth century. It was key to the Industrial Revolution. 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
South Wales Coal Measures Group "Cambriense" Marine Band, the South Wales rock sequence which had formerly been assigned to the 'Upper Coal Measures' (which was also referred to as the 'Pennant Measures') is no longer considered to be a part of the Coal Measures and is now designated as the Warwickshire Group which is itself subdivided into the Pennant Sandstone Formation and overlying Grovesend Formation. In South Wales, the South Wales Coal Measures Group is preceded (underlain) by the Marros Group which is of Namurian age though in southeast England, the Coal Measures directly overlies Devonian strata. It is succeeded (overlain) by the Warwickshire Group