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Petroleum & Gas Inspectorate | Alert | No.100 V 1 | 22 April 2022

Wire rope counterweight fall from height after becoming caught during rig up operations

What happened?

A winch line counterweight became snagged during rig up operations, causing the steel wire rope to break. The counterweight dropped to the rig floor, resting near the Derrickman. No persons were injured, however, the 5.7kg counterweight landed less than 1m from a rig worker.

How did it happen?

The rig crew were observing and monitoring the risk of the Bullhorn becoming entangled as the mast was raised. While raising the mast and observing other known risks, they did not observe the sand line counterweight was caught until the wire rope failed under tension. The counterweight dropped to ground level, narrowly missing a worker.

Key issues

  • The sand line counterweight became caught without workers becoming aware.
  • Persons were present in the vicinity of the rig floor performing checks on other risks associated with rig up.
  • The counterweight fell approximately 4m to ground level.
  • The 5.7kg counterweight landed less than 1m from a worker.
  • A serious injury or potential fatality was narrowly avoided without specific controls in place.

Critical controls

  • The critical control in this incident was the wire rope which failed when the counterweight was caught during the raising of the mast.
  • There were no critical controls in place after the initial control of the wire rope failed.


  • Risk assessments should include potential risk scenarios that have not previously occurred. Rig workers who carry out the work being assessed should be included in the risk assessment process.
  • Where potential risks are identified, existing critical controls should be assessed and steps to fail-safe considered.

Investigations are ongoing and further information may be published as it becomes available. The information in this publication is what is known at the time of writing.

We issue Safety Notices to draw attention to the occurrence of a serious incident, raise awareness of risks, and prompt assessment of your existing controls.

Authorised by Bill Date - Chief Inspector – Petroleum & Gas

Contact: Tony Willis, Manager Investigations , +61 7 5459 6191

Issued by Resources Safety & Health Queensland

Safety: This information 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.