Worker injured by unplanned initiation at mine site

Background

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.

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 300mm x 32mm primer and detonator which initiated. The hole also contained a 700mm length of Powergel. This remained uninitiated and partially ejected.

The Jumbo's centraliser shielded a large portion of the ejected blast gases from the bored hole. The centraliser was deformed backwards.

Safety issues

The unplanned initiation of explosives can create risks to health and safety through:

• exposure to harmful energy
• flying objects, and
• contaminated atmospheres

Identify hazards

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

Recommended 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.

Consult with employees

Mine operators must consult with employees when identifying, assessing and controlling hazards or risks. Employees can provide important information about what risks look like in their work. Employees with a broad range of expertise should be consulted. This will ensure all aspects of risk are considered.

Legal duties

Under the Occupational Health and Safety Act 2004, employers must, so far as is reasonably practicable, provide and maintain a working environment that is safe and without risks to the health of employees and independent contractors. This means employers must eliminate the risks associated with explosives, so far as is reasonably practicable. If the risk cannot be eliminated, it must be reduced, so far as is reasonably practicable.

Under the Occupational Health and Safety Regulations 2017, mine operators must:

• Identify all mining hazards at their mine and assess associated risks, so far as is reasonably practicable.
• Implement risk controls that eliminate or reduce risks, so far as is reasonably practicable.
• Establish and implement a safety management system for the mine, which provides a comprehensive and integrated management system for all identified risks.
• Consult with employees when identifying mining hazards and assessing risks.