Mines safety alert no. 378 | 08 September 2020 | Version 1

Structural Failure: Security of Suspended Objects

What happened?

While replacing a light in a CHPP, Coal Mine Workers identified that the shackle on the light was badly worn (see figures 1 and 2 below). The shackle was the only support point. In the event that the shackle had failed, the entire weight of the light would have been seen by the power cable.

Recommendations

All SSEs should audit the support configurations on all lights and suspended objects in CHPPs and other buildings to determine the integrity of the support configuration. The audit should consider:

• If the support configuration is fit for purpose.
• If a secondary restraint in necessary.
• Cracking in stress zones.
• Condition of welds.
• Condition of (worn or damaged) fasteners.
• Security of fasteners.

NB: AS/NZS 4871.1 2012 section 2.6.1 may provide some guidance

SSEs should review their maintenance strategies for CHPPs and other buildings to:

• Confirm that suitable support configuration inspections are in place for suspended objects.
• Confirm that the frequency of the structural inspections is adequate to identify potential failures before they become actual failures.

Safety Alert Purpose

• Draw attention to the occurrence of a serious incident in the mining industry.
• Increase risk awareness.
• Promote mines to examine and check that their controls are adequate.

The investigations are ongoing and further information may be published as it becomes available.

The information contained in this publication is based on knowledge and understanding at the time of writing.