Notching timber at Baldwin's Level, Pontypool c.1900.
You are now standing inBig Pit's timber stockyard. Making sure the roof is well supportedhas always been a satey concern for miners. Before modern steel arches were used, pit props were cut from timber using the 'Welsh notching' method as seen in the picture.
Miners in the past described a distinctive creaking if wooden props began to move: early warning of a roof fall.