In traditional room and pillar mining, a jud is a specific section of the coal face that miners have holed or undercut along the bottom. The block is left hanging, supported only by temporary props or its own internal strength, until wedges or light explosives are used to drop the entire mass to the floor for loading.
We left a solid jud at the end of the shift for the next crew to wedge down.
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.
Underhole
To excavate a deep groove at the bottom of a coal seam to help it fracture.
Coalface
The advancing boundary of a coal seam that is actively being mined.
Room and pillar
An underground mining method where material is extracted across a horizontal plane, leaving blocks of ore to support the roof.