The term kerf refers to a channel cut into a surface. A kerf cut is a thin (height), deep cut into a rock face that undercuts a section of a coal bed or a mineral seam. The kerf cut serves to provide an extra free face (to make blasting more efficient), or to weaken the rock or coal above the kerf (to induce easier breakage or caving).

Kerfs can be cut with flame jet tools, wire saws or diamond saws for harder stone. Typically chainsaw-like machines are used to cut coal and softer minerals. Kerf cutting is most commonly found in coal mining, soft nonmetallic minerals, and dimension stone.

Figure: A kerf cut can be used to undermine a deposit , and also create a free space for the overlying material to fall.