The burn cut, otherwise known as a parallel hole cut, is one of the most commonly used underground blasting methods because it can be used in drifts of all sizes and dimensions. The burn cut has also been tested in almost all rock types and can effectively break weak or strong rocks, depending on the design. In a burn cut round, five different classifications of holes exist that work together to create a round, which pulls effectively, leaves a good contour and is cost-effective.
The first of these holes is the relief holes (red box in Figure one) and are not loaded with explosives. These holes act as a relief point for the surrounding rock to break to, and they are normally larger in diameter, with both the diameter and the length of the hole controlling the total face advance of the round.