Cadia offsider loses arm in drill rig incident after boom left engaged, investigation reveals training gaps and sparks push for stronger safety controls

A serious workplace incident at Cadia East Underground Mine in June 2023 has triggered a sweeping safety review after a jumbo offsider suffered a traumatic arm amputation during routine drilling operations.

The NSW Resources Regulator's investigation report, released in May 2025, confirmed that the offsider — working only his third shift in the role — became entangled in a rotating drill steel after approaching an active jumbo boom without engaging its immobilisation system.

The incident occurred during night shift development work in the 4670 decline, where the jumbo drill rig was in use for bolting and meshing ground support. The drill boom continued rotating after the operator exited the cabin with a control lever still engaged. The offsider, attempting to insert a 3.7-metre steel into the moving coupling, had his left arm caught in the rotation. The injury resulted in an amputation below the elbow and a five-week hospital stay.

Investigators identified multiple systemic failures at the site, including:

• Routine failure to use immobiliser switches, despite documented procedures;

• No automatic detection system (e.g. laser barrier) to halt boom movement during personnel entry;

• Limited oversight from supervisors stretched across large sections of the mine;

• The injured worker’s inexperience — he had been primarily employed as a truck driver with no formal training as an offsider.

The report also included photos of the drill rig (page 5) showing the location of the immobiliser switch and the worker’s position at the time of the incident — with his shirt visibly entangled in the steel, underscoring the proximity risk.

The Regulator’s recommendations include mandatory immobilisation of all jumbo booms prior to physical interaction, improved engineering controls such as automatic cut-off systems, closer monitoring of boom activity via dashcams or data loggers, and enhanced training and supervision of all jumbo crews.

This incident follows a previous safety alert (SA23-02) and interim information release (IIR23-06) issued shortly after the event. The regulator has reiterated that failure to enforce control measures in high-risk tasks will lead to serious consequences and potential prosecution.

The Cadia East Underground Mine, located 20 kilometres south of Orange and operated at the time by Newcrest Mining, is one of the largest gold and copper operations in the state. Labour-hire firm Face Mining Services Pty Ltd employed the injured worker.