Microsleeps are generally the result of fatigue or other underlying physical or mental condition.

The inspectorate said that site senior executives should ensure the mine's safety and health management system contains effective procedures and controls for fitness for duty.

"Implement effective controls to mitigate fatigue-related issues," it said.

Supervisors should ensure coal mine workers understand the requirements for fitness for duty requirements.

"Monitor adherence to the processes for fatigue management," the inspectorate said.

Coal mine workers should ensure that on presenting to work they have complied with the fitness for duty requirements.

"Inform your supervisor of any concerns about issues related to fitness for work," it said.