nicking
The cutting made by the hewer at the side of the face.
nicking: undercut that frees stone from the coal seam
In coal mining, nicking is a horizontal cut made at the base of the coal face, typically 3 to 6 feet high and extending 12 to 18 inches back into the seam. The hewer drives a pick or mandrel along the side of the working face to create this undercut, which allows the upper coal to break and fall cleanly when wedges are driven or the overlying strata settles. Without the nick, coal tends to bind to the surrounding stone and requires excessive force to extract.
The nick serves a structural purpose: it breaks the continuity between the coal and the roof rock or stone above it, creating a natural plane of weakness. When coal is left standing without this cut, it behaves like a cantilever beam, resisting fracture and causing the hewer to work far harder to loosen it. A properly executed nick reduces the physical demand on the miner and speeds the extraction rate.
Nicking practice and variation
The depth and angle of the nick depend on coal hardness, seam thickness, and the roof condition. In thin seams, the nick may be shallow and narrow; in thicker seams, deeper undercuts are economical. The hewer works by hand or with pneumatic tools, moving laterally along the face and gradually deepening the cut. The debris (slack and coal dust) falls into the space created, which the miner then clears before advancing further.
Proper nicking technique requires skill and experience. A nick cut too high or at the wrong angle may not fracture the coal as intended, wasting labour. If cut too deep, it weakens roof support and risks falls of stone. The terminology reflects the physical action: the hewer "nicks" or notches the face, much as a carpenter nicks timber before splitting it along the grain.
Nicking remains standard practice in hand-worked and semi-mechanised coal mines where conventional longwall or bord-and-pillar extraction is used. Its importance diminishes in fully mechanised systems, where shearers and other continuous miners apply force along the whole seam height at once, eliminating the need for selective undercutting by hand.