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Coal Inspectorate | Alert | No.429 V 1 | 01 June 2023

Inservice failure of an explosion protected diesel engine safety system

What happened?

While investigating the cause of a mine dozer shutting down a Coal Mine Worker (CMW) opened the diesel particulate matter filter compartment and observed that the filters were beginning to ignite. The CMW extinguished the fire. 

Smoke from the incident entered an inbye panel, CMWs in the panel subsequently retreated to a place of safety.

How did it happen?

The investigation is ongoing. However, it has been confirmed that the scrubber water feed isolation valve was in the off position and the safety circuit flow controller was nearly fully wound out. This has rendered the scrubber low water shut down to be ineffective.

Key issues

  • The low scrubber water shut down test was not conducted as required by the prestart inspection.
  • The scrubber water isolation valve was left in the off position after a maintenance intervention.
  • Fault finding procedures for diesel engine safety circuits may not have been adequate / followed.


All site senior executives should:
  • ensure that prestart inspections for explosion protected diesel engines, as required by the Safety and Health Management System (SHMS), clearly instruct CMWs to test safety functions.
  • ensure that technical information and training on explosion protected diesel safety circuits is provided to tradespersons. In addition to training in mandatory competencies specific machine training should also be provided.
  • audit the prestart inspection process to identify that safety system tests are completed consistently and correctly.

All supervisors should:

  • provide leadership to CMWs and ensure that safety system tests are completed and the SHMS is followed.
  • ensure that technical information and training on explosion protected diesel safety circuits is up to date and readily available. Machine specific troubleshooting guides should be provided.
  • ensure that CMWs attend technical safety circuit training as scheduled. For equipment used infrequently refresher training prior to use of the equipment should be provided.

All CMWs should:

  • be familiar with the requirements of the SHMS, in particular prestart tests, and inspections.
  • comply with all requirements of the SHMS.
  • understand and follow safety circuit technical fault-finding procedures.

Investigations are ongoing and further information may be published as it becomes available. The information in this publication is what is known at the time of writing.

We issue Safety Notices to draw attention to the occurrence of a serious incident, raise awareness of risks, and prompt assessment of your existing controls.

Authorised by Jacques le Roux - Chief Inspector – Coal

Contact: Mick Scully, Inspector of Mines , 0459 878 917

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.