In underground mining a great deal of time, money, effort, and resources have been used in the effort to minimize blast-induced damage. This damage occurs to the back, ribs, and pillars when the energy of the explosive is released back into the rock due to over confinement or the overloading of explosives in the perimeter holes. This damage can result in roof falls, dilution of ore, excessive rock bolting, scaling, screening, shot-creteing and other safety and support issues. For decades perimeter holes have been loaded with decoupled charges, coupled charges, low density ANFO's/emulsions, and various strength detonating cords. Additionally ANFO traced with detonating cord, and continuous pre-split explosives have been utilized Results from these products vary from shot to shot. This variability is due secondary to each miner's experience, training, and the time and effort required in loading these products. Often overlooked, perimeter blasting is an important step in any underground blasting program. This paper will explore the different methods and their application. By incorporating a perimeter blasting program an underground mine can see improvement in scaling time, bolting, dilution control, and overall creating a safer workplace for the miner to be productive in.
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