Brakes, Brake Failure & Uncontrolled Rolling
Incidents
Queensland, 2006 Project
Queensland Mine Site
Cranes
Iveco Acco 2350G truck
The Outcome
• Near miss
Key Learning
• Limitations to brake design • Ensure park brake works whether ignition is on or off • Driver’s understanding of the braking system was
inadequate – drivers must be aware of design weaknesses
An unattended partly loaded bulk explosives truck was parked with its engine running. The driver had applied the parking brake before disembarking and was walking away from the truck when he noticed it moving. While the truck was rolling away, he climbed back in the cab and stopped the truck by applying the foot brake. The truck had travelled about 20 metres and ended up with its front wheels suspended over the edge of a 2.5m drop.
•
The park brake lever is designed to be locked into position by a detent (a spring-activated pin that automatically drops into a catch hole). Tests showed that the parking brake could be ‘applied’ while the pin remained unlocked. A slight jolt to the lever was all it took to release the brake.
The park brake lever did not lock into position when applied. When the driver closed the door as he left the cabin, the vibration jolted the lever into the release position.
•
The truck’s ‘brake not applied’ alarm is activated by a sensor that monitors the position of the lever rather than the status of the detent.
The Department of Natural Resources, Mines and Energy identified several learnings in their mine’s safety alert (no. 150) outlining the incident, including:
•
Post-incident testing revealed that the alarm worked only when the ignition was on.
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LIFTING MATTERS
JUNE 2019
