The exact cause of an accident which led to the death of a rigger last year at Boggabri mine construction site has been narrowed down to several possibilities in a final report from the NSW Mines Safety Unit.
Mark Daniel Galton, 51, had been employed on site for only 11 weeks, and held a national High Risk licence for less than 18 months, when he was involved in a fatal accident in which his head and neck were crushed between the hand rail of an elevated work platform (EWP) and an overhanging steel beam.
The final investigation report from the NSW Mine Safety Investigation Unit showed that in the morning of May 22nd last year Galton had been operating a JLG 600AJ EWP tightening structural bolts with a rattle gun, when he attempted to return to the ground.
Galton had manoeuvred the basket of the 18 metre, knuckle boom-type machine into a difficult position in order to reach bolts for tightening, with the jib section above a beam but underneath a diagonal member and a walkway.
Galton had a spotter on the ground, but asked a leading hand rigger to spot from the platform above.
The leading hand rigger was not a designated spotter and did not witness the incident, and the spotter on the ground was unaware Galton had been injured.
The report showed that the leading hand told Galton he could return to the ground, and began to walk away when he saw Galton begin to raise the basket.
The leading hand warned Galton with the question, “Stop, what are you doing?” which Galton acknowledged, responding “Yeah, okay”.
The leading hand made the following observation: ‘Then I saw Mark facing east still in a standing position leant forwards over the control panel in the EWP. He had both hands still on the controls with his head coming forward but still upright as if he was looking forwards towards the mine. His head was jammed in between the beam above and a hand rail which is over the control panel.’
The spotter’s normal duties were as a site crane operator, and it was the first time he had undertaken a spotting role on the site.
On the day in question Galton and the spotter signed onto a Theiss Sedgeman start card dated 5 March which was for a ‘180T Kobelco Crawler Crane for general lifts and operations’, which was not the correct JSEA for work undertaken.
Galton and the leading hand rigger signed a start card on 20 May for ‘rattling steel’ and referred to a JSEA for ‘Sizing station structural erection of structural steel at ST202’.
It was also shown that the working at heights permit signed by Galton and his spotter was valid for structure ST801, but not ST202, the structure on which they were working on the day of the accident.
A second spotter who had been working on ST202 on the previous day said he did not know why Galton had been assigned the work, and that Galton had ‘put his hand up’ to volunteer for the job that day.
The second spotter told investigators it was his opinion that he had observed competency issues with Galton operating EWP machines before the day of the incident, that Galton had required extra time on his Verification of Competency on site, and that Galton had needed instructions to be able to manoeuvre the basket into position on the day of the accident.
No other evidence was found to suggest that Galton had competency issues with operating the EWP.
It was shown that Galton was relatively new on site, having been employed by Theiss Sedgeman for 11 weeks, and had held his High Risk Work licence for one year and five months.
Records indicated that Galton had operated EWPs on that site on at least two occasions: at his VOC on March 4, and on 22/23 April when he signed on to two working at heights permits.
It is not known if he personally operated an EWP on that occasion.
The report was unable to pinpoint the exact reason for Galton’s death, instead offering five possible scenarios.
The most probable scenario involved Galton leaning over the platform console, presumably to look for a way down, and inadvertently activated a control which raised the basket.
The second scenario supposed Galton had meant to lower the basket, but accidently raised the basket instead.
Third, that Galton intended to raise the basket.
The fourth scenario presumed an electrical fault with the controls, however testing did not reveal any probable reason for this to be the case.
The least likely scenario was that an environmental force such as soft ground movement caused the tyres of the machine to dip, which would have raised the basket, however the machine was located on firm ground.
The report stated that the risk of a worker becoming trapped between the platform and a steel structure was a foreseeable hazard, clearly identified in risk assessments and equipment manuals prior to the accident.
It was recommended that in events when EWPs are required to move in proximity to large structures, higher order risk management controls should be employed, specifically with controls implemented to prevent crush injury.
Such controls could include alternative access methods such as scaffolding, secondary guarding for the EWP basket, and assessment of inadvertent activation of platform controls through bodily contact or incorrect control selection.
Immediately following this accident, on 30 May 2014 Worksafe WA awarded Australian Design Registration for a JLG after-market kit called SkyGuard, a bar fitted above the controls which stops machine movement if pressed intentionally or accidentally by the operator.
Prior to that date JLG had recieved no orders for the SkyGuard after-market kit.
Image of Mark Galton: Claudine Thornton Photography