The act of making a vertical cut along the side of a solid block of coal or rock at the working face. By creating this vertical slot, miners provide a free face that allows the remaining block to expand and break apart more easily when blasted or wedged. It is usually paired with undercutting, which removes the bottom support, leaving the coal block attached only at the back and top.
Heard on the job
The machine finished undercutting the seam and is moving over to start shearing the left rib.