16th January 1862 Hartley Colliery Disaster in Northumberland, England.
Hartley Colliery Disaster, article rom Wikipedia     https://en.wikipedia.org/wiki/Hartley_Colliery_disaster#:~:text=The%20Hartley%20Colliery%20disaster%20(also,two%20independent%20

THE HARTLEY CALAMITY   - The High Level Ranters       https://www.youtube.com/watch?v=hbpV6BFRz5E
The Hartley Calamity, song information and Lyrics https://www.chrisharrisonmusic.org/musical-activities/carols-from-the-coalfields/hartley-calamity

NEW HARTLEY PIT DISASTER, BROTHERS SONS AND DADS  - The Sawdust Jacks       https://www.youtube.com/watch?v=qga1LvwagIc
Information from Durham Mining Museum     http://www.dmm.org.uk/pitwork/html/hartley.htm