Coal Inspectorate | Alert | No.422 V 1 | 12 January 2023
Effective implementation of hazard control for continuous-miner rib-protection system
What happened?
On 27 July 2020 two coal mine workers (CMWs) received serious injuries from rib spall while working on a continuous miner (CM) in an underground development panel heading.
The incident occurred as the CMWs were installing roof support and extending ventilation tubes. An inspection of the site revealed that the machine mounted rib protection system installed on the continuous miner did not provide an effective control for this hazard.
Safety Alert 377 was published on 27 August 2020 soon after the incident occurred, and the Inspectorate commenced a detailed investigation into the incident. The investigation has now been finalised with all factors – including the design, installation and practical application of the engineering controls – being considered. The findings and recommendations from this investigation follow.
Key issues
The Inspectorate’s investigation into the incident identified:
- That the rib protection installed on the fleet of CM, did not provide effective protection from rib spall to CMWs, with the mine identifying the following solutions:
- Preferred control: Install hydraulically-powered adjustable rib protection (significant effort to design, build and install required).
- Interim control: Fit a polyurethane sprag to extend the range of the rib protection.
- The mine had a fleet of three CM supported by two different original equipment manufacturers (OEM).
- At the time of the incident, CM2 was at an OEM workshop undergoing an overhaul. The mine had commissioned the OEM to design and install hydraulically-powered adjustable rib protection to CM2. The modified CM2 was returned to service underground and found to provide effective rib spall control.
- CM1 and CM3 were supported by a different OEM and were not scheduled for overhaul, the polyurethane sprag was installed on these CM as an interim control.
- The mine has commissioned the OEM of CM1 and CM3 to design and build hydraulically powered adjustable rib protection.
- The polyurethane sprag interim control, has since proved ineffective with other CMW also receiving injuries from rib spall during their operation.
- The mine has ceased use of CM1 and CM3 due to ongoing incidents and has commissioned a third party to build hydraulically-powered adjustable rib protection CM using the finalised OEM design drawings from CM1.
The attached causal diagram (Figure 1) was determined from the investigation.
Recommendations
All Site Senior Executives should:
- Following an incident, ensure that until the preferred solution is implemented, effective interim controls are immediately implemented to manage the risk - or suspend operations until the engineered solution can be implemented.
- Regularly audit to confirm the risk of injury from rib spall is risk assessed, and effective control measures are identified and documented in the safety and health management system.
- Ensure regular periodic audits for compliance against the managers support rules and that the build reflects the design.
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.
Contact: Michael Scully, Inspector of Mines , 0459 878 917 QldMinesInspectorate@rshq.qld.gov.au
Issued by Resources Safety & Health Queensland
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.
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