Miners traditionally performed this manual technique by cutting a deep groove into the lower face of a coal seam or rock bed using hand tools. Removing this basal support allowed the overhanging material to be wedged down or blasted much more easily, maximizing the yield of large blocks.
Heard on the job
The men spent the whole morning jadding the bottom of the seam before setting the charges.
Related terms
Holing
The process of cutting a slot or groove at the base of a coal seam or ore face to facilitate blasting or breaking.
Undercutter
A mechanized coal-cutting machine that slices a horizontal slot at the base of a seam.
Facework
The active extraction and support tasks performed directly at the working face of a mine.