The Pretoria Colliery Disaster occurred on the 21st December 1910, and is on of Britain's worst mining disasters. An underground explosion claimed the lives of "344 men and boys". Occurring as it did immediately before Christmas it had a devastating affect on the people of Chequerbent, Over Hulton, Westhoughton and surrounding areas.
After the disaster the colliery re-opened finally closing in 1934.