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Coal Inspectorate | Bulletin | No.214 V 1 | 29 August 2023

Dozer falls into coal stockpile void

What happened?

On 4 November 2022, a bulldozer fell backwards into a coal valve void during train load-out operations. The investigation for this incident has now closed with a number of recommendations listed below, to avoid future dozer stockpile incidents. This particular incident was one of several involving dozers from 2022 and 2023.

How did it happen?

Preparation for train load out had been conducted on the previous shift by constructing a ramp onto the stockpile to the assumed position of the coal valve. At the time of preparing the stockpile, the coal valve was closed and it is probable that the valve became bridged partly due to pushing significantly beyond the valve position.

The site applied physical indicator poles outside of the stockpile footprint for dozer operators to use as a visual reference. This visual reference provided only one part of a grid reference required to identify the voids actual position. The indicator poles were not necessarily visible by dozer operators at all times because of the height and shape of the stockpile. There were no other indicator poles to provide a secondary (right angle) reference point for the void position, however, the reclaim conveyor is commonly used for this purpose.

During the shift when the incident occurred, there were two dozers assigned to stockpile push operations for train load out. Just prior to the incident, the operator of the dozer involved in the incident (dozer no.1) had line of sight for the second dozer. Dozer no.2 was on the southwest side of the stockpile. It was assumed by the operator of dozer no.1 that dozer no.2 was pushing into the coal valve position. An assumption was made by the operator of dozer no.1 that coal was flowing due to coal dropping off the blade of dozer no.2. There were no positive communications made between the two dozer operators at this point.

At the site where the incident occurred, it was a requirement of the site’s Standard Operating Procedure (SOP) to visually confirm the coal valve location when the coal valve turned live. On this occasion, the bulldozer push commenced before operators visually confirmed the coal valve location. Dozer no.1 pushed coal to the position where the coal valve was thought to be after observations of dozer no.2 previously mentioned. Dozer no.1 conducted a second push to the same position and while reversing, dozer no.1 slumped backwards into a void created by the coal valve which was behind them and the material thought to be bridging the valve letting go. The operator was recovered by the Emergency Response Team (ERT) without injury.

Key issues

The investigation identified that:


Site Senior Executives (SSEs) should:

Coal stockpile operators should:

Authorised by Jacques le Roux - Chief Inspector – Coal

Contact: Paul Brown, A/Regional Inspector of Mines , +61 7 3199 8001

Issued by Resources Safety & Health Queensland

Safety: This information is issued to promote safety through experience. It is not to be taken as a statement of law and must not be construed to waive or modify any legal obligation.
Placement: Place this announcement on noticeboards and ensure all relevant people in your organisation receive a copy, understand the content, findings and recommendations as applicable to their operation. SSEs should validate that recommendations have been implemented.

All information on this page (Dozer falls into coal stockpile void - is correct as of time of printing (Oct 4, 2023 4:42 pm).