Date of incident: March 2022
Notice of incident number: 2022161750005
Employer: Road construction company

Incident summary
At a remote forestry operation, a blaster’s assistant and an excavator operator were standing on a road having a conversation. A few hundred metres away, a blaster detonated explosives as part of a blasting operation. The assistant was struck by a piece of fly rock (a rock propelled from the blasting area). He sustained serious injuries.

Investigation conclusions

Cause

• Worker not at designated safe location was struck by fly rock. Before the detonation, the assistant was directed to move to a safe location identified by the blaster. However, the assistant did not move to that location, and the piece of rock flew approximately 220 m and struck him.

Contributing factors

• Failure to follow safe work procedure. At the time of detonation, workers are to move to the identified safe location, where they are to remain until the clear signal is given. However, the safe location was not located outside the blast danger area. Furthermore, the required audible blasting signal was not sounded because the air horn on the drill was not working.
• Inadequate drill pattern. In a blasting operation, the blasting crew drills a series of holes in the ground and loads them with explosives. The drill pattern used did not allow for relief in the rock — that is, it did not allow the rock to move toward the free face (the side away from the hillside). As a result, the only direction for the rock to move was up.
• Communication failures. The excavator operator was not aware that a detonation was about to occur and that he was required to move to a safe location. The blaster provided a five-minute warning over the radio for the impending detonation. However, the excavator operator was outside of the excavator and did not hear the broadcast on the radio, which was mounted inside the excavator. The assistant heard and acknowledged the broadcast but did not provide the details to the excavator operator. In addition, the blaster was unable to sound the required audible signal because of the broken horn on the drill.
• Ineffective supervision. The employer did not provide effective supervision for blasting operations, which allowed unsafe conditions to develop and placed the health and safety of workers at risk.

Other health and safety issues

• Transportation of explosives. Explosives and detonators were carried in the same day box on the drill, in contravention of the Occupational Health and Safety Regulation. Furthermore, the employer failed to display adequate signage on the day box, in a conspicuous manner, indicating the presence of explosives.
• Failure to maintain visual supervision of assistant. The employer did not ensure that its blasters exercised visual supervision of assistants without blaster’s certificates while explosive loading, priming, fixing, or firing was taking place, as is required by the Regulation.

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