For almost 50 years the worst mining disaster in the UK was at the Oaks Colliery, near Barnsley, where two explosions killed 361 men and boys.
However on the
14th October 1913 an explosion ripped through the heart of the Universal Senghenydd Colliery in South Wales killing 436 miners. Of the 436 who died, only 72 bodies were recovered.
More info on the colliery and the disaster.