The two coal mine workers were assigned to maintain a surface drill.

During an inspection by their supervisor, there were found to be significant deviations from the SHMS.

These include the drill not being isolated and personal protective equipment requirements for the task not being met.

The coal mine workers were also working under a suspended load.

The inspectorate said site senior executives should confirm coal mine workers were trained and competent in the relevant procedures required by the SHMS.

"Ensure the maintenance system is effective in managing the risks," it said.

"Ensure supervisors are monitoring and verifying effective use of risk controls."