Originally published by the Australian Institute of Health & Safety

WorkSafe Victoria recently issued a safety alert reminding mine operators about managing the risks associated with explosives following an incident in which a jumbo drill operator was injured when the drill struck live explosives.

The drill was boring a development face in an underground metalliferous mine, and 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. The operator received several minor facial lacerations which required medical treatment.

At the point of initiation, the newly bored hole was approximately one metre deep. The hole from the previous cut contained a primer and detonator which initiated. The hole also contained a length of Powergel, but this remained uninitiated and partially ejected.

The jumbo’s centraliser shielded a large portion of the ejected blast gases from the bored hole, while the centraliser was deformed backwards.

The safety alert said the unplanned initiation of explosives can create risks to health and safety through: exposure to harmful energy; flying objects, and contaminated atmospheres.

Mine operators must identify all hazards at a mine site and assess the associated risks, and this includes the risk of unplanned initiation of explosives.

The alert recommended a number of ways to control risks:

• Implement processes and systems to:
  
  • Identify and control the risk associated with uninitiated explosives. This should include washing out, cleaning, inspecting and marking up all ‘Butts’ in development faces.
  • Manage and account for explosive stock levels during each stage of the blasting activity. This includes storage, transport, pre and post-blasting.
• Regularly review processes and systems to ensure they are effective.
• Ensure pre-task inspections target uninitiated explosives post-blasting activity.
• Provide employees with information, training and instruction about how to identify and manage uninitiated explosives in a mine.