Dump truck with unbalanced load becomes unstable

Mine type

Metalliferous mine – surface

Incident

A Komatsu 830 dump truck had just been loaded and was moving from the production bench into the main access ramp. A large rock that had been loaded on the truck moved to the right side of the truck, causing the truck to twist to the right, with the front left wheel leaving the ground. The tray dropped until it was touching the rear right wheels. The truck was stopped and a shocked but uninjured driver recovered from the cab.

Equipment

Dump truck and face shovel

Hazard

Instability of large rock with last shovel load placed on truck tray

Cause

Positioning of the final shovel load was not stable on the truck resulted in movement of an oversize rock while transporting up the ramp for the crusher.

Comments and recommendations

• A standing instruction that large rocks are not to be loaded but re-blasted was ignored by the shovel operator.
• If large rocks are to be loaded they must be bedded down in a stable position.
• The standing instruction to leave large rocks for re-blasting is to be reinforced.

This accident had a high fatality potential.

Authorised by Peter Minahan - Chief Inspector of Mines

Contact: minesafetyandhealth@dnrm.qld.gov.au

Issued by Queensland Department of Mines and Energy