An investigation into a recent roof collapse at Evolution Mining’s Cowal gold mine in New South Wales that caused injury to a jumbo drill rig operator is underway.

Cowal is both an underground and open cut mine that commenced operations in 2005. Barminco is responsible for the site’s underground mining operations.

The incident occurred on March 9 2025 during ground support installation where drilling operations using a jumbo drill rig were conducted to create holes for friction-type bolts (split sets) to be installed.

Two Barminco workers were undertaking the installation in ore drive north 15 on the 690 level, about 500 metres below the surface.

One performed the role of jumbo operator and the other the role of offsider (nipper), with each having specific duties.

Ordinarily, an offsider may be positioned alongside or in front of the jumbo, but at the time of the incident, he was momentarily absent from these areas.

According to findings from the NSW Resources Regulator’s attendance at the scene, at about 2:02pm, a significant roof collapse occurred.

The collapsed roof was estimated to be about 10.9m in length by 4.4m tapering in towards the rear of the drive, with a wedge shape extending to an apex of about 2.7m.

The jumbo, including the operator’s cabin, was engulfed and partially buried by the material.

The operator suffered a laceration while extricating himself from the jumbo and material, but the offsider was not injured. Nearby workers promptly attended the scene and provided assistance.

The Regulator’s investigation will aim to determine the cause and circumstances of the incident, including the:

• mechanism of the incident, including its foreseeability and the reasonably practicable steps available to guard against it
• operation of the plant and equipment involved in the incident
• adequacy of the following:
  – mine and contractors’ safety management systems including risk assessments and procedures
  – the safety management systems in identifying and addressing changes in strata conditions before continuing with planned mining activities
  – contractor management plans, policies and procedures
  – instruction, training, work practices, experience and supervision of workers.

Findings are expected to be released in the coming months.