21 December 1910 The Pretoria Pit Disaster was a mining accident . Three hundred and forty four men and boys lost their lives in an underground explosion at the Hulton Colliery Bank Pit No. 3, known as the Pretoria Pit, in Over Hulton, Westhoughton, Lancashire, England.

THE PRETORIA PIT DISASTER  -  Houghton Weavers    https://www.youtube.com/watch?v=UPu-g-lcXM4
Pretoria Pit disaster from Wikipedia     https://en.wikipedia.org/wiki/Pretoria_Pit_disaster