Mineral Mines & Quarries Inspectorate | Alert | No.433 V 1 | 06 September 2023

Unplanned movement of bulldozer into reclaim feeder

What happened?

On 30 May 2023 a bulldozer was conducting ‘push in’ activities on a coarse ore stockpile when an unplanned movement occurred, resulting in the bulldozer travelling past the stockpile lip and sliding forward into the reclaim feeder below.

This incident follows recent safety alerts and bulletins from the Inspectorate regarding coal stockpile operations, and bulldozers exposed to uncontrolled movement/falls into stockpile voids.

How did it happen?

Investigation into the incident is ongoing, however several contributing factors were identified including:

• the creation of a significant 'feed cone' through operation of the feeders to a point where they were no longer covered with material
• limited visibility of the stockpile edge or 'lip' when pushing uphill on the stockpile
• the dynamic nature of the stockpile edge and the changing position of the edge during operations.

Key issues

• Insufficient engineering controls to prevent development of significant 'feed cones' in stockpiles
• Reliance on lower order administrative or procedural controls for mobile equipment operations on stockpiles
• Visibility and identification of edges of stockpiles when conducting mobile equipment operations.

Recommendations

Mines should:

• ensure the hazard of mobile equipment entering feeders on stockpiles is identifies as a potential fatal hazard on site
• ensure appropriate controls are put in place according to the hierarchy of controls
• review the types of mobile equipment used for stockpile operations to ensure only appropriate types are being used
• ensure controls are put in place to eliminate the creation of significant 'feed cones' at stockpile feeders during mobile equipment operations. Such controls could include the automatic monitoring of stockpile levels and automatic controls of feeders
• consider fitment of camera-based vision systems for mobile equipment to aid operator visibility
• consider fitment of GPS-based positioning and hazard identification systems for mobile equipment.

References and further information

The Queensland and New South Wales mines inspectorates have published information regarding the hazards of operating buklldozers on stockpiles. Receht industry safety alerts include:

• Safety Alert 420 Bulldozer drops into a void above a conveyor feed valve point.
• MDG 28 Safety requirements for coal stockpiles and reclaim tunnels.
• Safety Alert 424 Dozers entrapped in stockpiles voids above feed valves.