Resources Safety and Health Queensland’s (RSHQ) coal chief inspector has issued a warning to miners after identifying a pattern that could lead to “serious injury”.
RSHQ has reviewed data of high potential incidents at Queensland coal mines and found 26 crowd cylinder failures on load haul dump (LHD) machines over the last 14 years.
A hydraulic cylinder that converts hydraulic energy into mechanical force, a crown cylinder is used to compensate for deformation in bending machines as it undergoes extreme forces.
“No one was injured in these incidents but there is a serious risk that LHD crowd cylinders may fail when coal mine workers are working in or near man baskets, bolting platforms or implements attached to the LHD lift arms,” RSHQ said.
“The LHD is a multipurpose machine by design, as such it can be one day mucking out stowage, the next transporting heavy loads, the next lifting men above ground level.
“Due to the lift arm geometry of most underground coal mine LHDs, a failed crowd cylinder can cause the implement to drop and rotate about the lower load arm pivot joint.”
This means coal mine workers working in a man basket, on a bolting platform or similar attachment, or in proximity on the ground could be placed at immediate risk of serious injury.
Based on investigation reports received by RSHQ there appears to be multiple crowd cylinders failure modes, and fixed time replacement of crowd cylinder may not be effective in eliminating failures.
RSHQ said it is critical for miners to identify the hazards associated with working on or near LHDs and implement effective and sustainable controls.
Some recommendations from RSHQ include:
- Review inspections and maintenance schemes for the machines
- Restrictions on who can use the machines
- Secondary measures restricting movement of the basket should a cylinder fail
- Contact the original equipment manufacturer (OEM) for LHDs and seek engineering controls to prevent implements from dropping and rotating about the lower load arm pivot joint in the event of a failed crowd cylinder
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