A Jumbo drill operator was injured when the drill struck live explosives. This resulted in an unplanned initiation and detonation. The drill was boring a development face in an underground metalliferous mine. As the drill was boring the left-hand wall ‘Knee’ hole, the operator heard a loud explosion and sheltered behind the console. Blast gasses and rock fragments were ejected towards the operator who then depowered the rig and exited the area.