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Learnings from suspension link pin incident

A fitter was injured when a suspension link pin struck him following lancing

The NSW Resources Regulator has released a number of learnings from an incident involving a suspension link pin that ejected and struck a fitter (resulting in hospitalisation) following lancing (See original article and images) .

The Regulator said that a Caterpillar haul truck was taken to Ravensworth open cut mine’s workshop for a 40,000-hour programmed component replacement on 4 July 2019.

Four days into the work schedule, fitters tried to remove the front, lower left-hand side, rear suspension link pin. They withdrew the pin about 70 millimetres with the available tools, before deciding it had become seized. The fitters then asked a boilermaker to lance the pin.

Thermal lancing is a regular practice to remove seized pins and involves piercing a hole through the axis of the pin followed by water quenching. Quenching rapidly cools the pin, reducing the outer diameter, making it easier to remove.

At 1.15 am on 9 July 2019, a boilermaker spent about 20 minutes lancing the pin. Having driven a hole, he used water to quench the pin. Fitters tried to pass a pry bar through the hole to knock out the inner collet but could not get the pry bar all the way through. Removing the inner collet was required to install the nut on the pull rod. The fitters then asked the boilermaker to open up the hole by lancing it a second time. At 1.49 am, the boilermaker spent a further six minutes enlarging the hole. The moment the boilermaker applied water to the face of the pin, rapidly forming steam ejected the pin under pressure. The pin – weighing 46.7kg – was propelled at the boilermaker, hitting him in his left hip and knocking him over.

An emergency response was activated. The spotter who was working with the boilermaker rushed to isolate the oxygen supply to the lance, while the fitters contacted the workshop supervisor. The boilermaker was taken to Singleton hospital and later transferred to Newcastle’s John Hunter Hospital. The boilermaker suffered a large hematoma and small crack to his left hip, a greenstick fracture to his left thumb and minor facial and eye injuries from the slag spray. The spotter was uninjured.

The Video has been created by the Regulator detailing the incident.

The report on the suspension link pin incident is available here

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AMSJ April 2022