Coal Inspectorate | Alert | No.431 V 1 | 02 August 2023

Dragline collision with cable tractor

What happened?

At a surface coal mine on Sunday 23 July 2023, a dragline house collided with a cable tractor that was stationary in the operational swing boundary of the dragline house. The coal mine worker in the cable tractor was uninjured in the collision and immediately moved the cable tractor outside the swing boundary after the incident.

How did it happen?

The coal mine workers were engaged in walking the dragline into position for the next production stage. The cable tractor was used for relocating the trailing cable during the walking and production set up process.

At the end of this process, the coal mine worker in the cable tractor notified the dragline operator by two-way radio that the cable work was completed, and the cable tractor was positioned clear of the dragline.

The dragline operator started to swing the dragline, rotating it clockwise, cab away from the cable tractor. The tail of the dragline house collided with the right-hand side of the cable tractor causing damage to the tractor/s operator cabin and other parts. The cable tractor operator was not physically injured and moved the cable tractor further away from the dragline, exited the machine and signalled the dragline operator to stop. The incident scene was isolated and an investigation commenced.

The reference points used by the cable tractor operator to locate the cable tractor clear of the dragline house swing radius were ineffective.

Key issues

• A coal mine worker has been exposed to a hazard by remaining within the operational boundaries of moving equipment.
• The investigation will consider issues such as the methods of managing proximity of coal mine workers to moving equipment and the methods used to verify coal mine workers have exited equipment operational zones.

Recommendations

Site Senior Executives should:

• provide effective methods for coal mine workers to identify the limits of dragline hazard zones, for example by providing measuring devices, or large enough distances that enable coal mine workers to estimate clearance distances.
• install cameras in known blind spots.
• provide an effective system, like proximity detection, to control risk associated with the movement of equipment and personnel when working in and around draglines.
• review and implement where applicable the actions taken after the dragline fatality in November 2021, including proximity detection.

References and further information

The Queensland Mines Inspectorate has produced Safety Notices concerning working around draglines, including collisions with cable tractors.

• 23 November 2021 - Safety Alert 403 Fatal accident when coal mine worker was struck by rotating dragline.
• 21 June 2017 - Safety Bulletin 162 Mobile equipment collisions.
• 28 October 2015 - Safety Alert 319 Dragline and cable tractor interaction.