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Petroleum and gas safety information bulletin no. 12 | 07 October 2020 | Version 1.0

Uncontrolled movement of winch line

What happened?

The floor hand had connected the bushing pullers to the driller's side winch line and was moving the hooks into position by holding the chains. As the driller winched up, the winch line became taut under the load and then released suddenly causing the winch line, chains and hooks to whip upwards uncontrollably. During this uncontrolled movement of the winch line the chain struck the hand of the floor hand causing injury.

How did it happen?

The swivel joint connecting the winch line to the chains became snagged on a protruding 13 inch x 3/4 running thread on the Top Drive slide adjustment. As tension was placed on the winch line the thread bent in an upwards directions allowing the swivel joint to suddenly release and the winch line, chains and hooks whipped in an upwards direction uncontrollably.

Key issues

  • The protruding 13 inch x 3/4 running thread was not identified as a potential snag point.
  • Floor hand did not visually check the winch line for snag prior to winching up.


  • Inspect rig especially in the area of the mast and winch cable to ensure snags point are identified.
  • In consultation with the OEM, implement an engineering solution to eliminate or guard potential snag points.
  • Review of procedures to ensure that during winching activities the winch cable is checked to ensure cable is free and clear.

References and further information

Queensland Legislation:

  • The Petroleum and Gas (Production and Safety) Act 2004
  • The Petroleum and Gas (Safety) Regulation 2018
  • Work Health and Safety Act 2011

Current Queensland Legislation at:


Contact the Inspectorate:

Website: https://www.business.qld.gov.au/industries/mining-energy-water/resources/safety-health/petroleum-gas

Authorised by Bill Date - Chief Inspector

Contact: Don Harris, Principal Inspector- Drilling , 07 4531 8521

Issued by Resources Safety & Health Queensland

Safety: This information is a guide only and is issued to promote safety through experience. It is not to be taken as a statement of law and must not be construed to waive or modify any legal obligation.