In the incident the driver of an unloaded haul truck had to use the engine brake to stop the truck after the service brakes failed.

The truck travelled about 100m before it stopped next to a workshop area.

The regulator said it appeared the driver did not apply the emergency brake system.

The truck had only been operational for about 15 minutes after returning from having repairs done on broken wheel studs.

The NSW Resources Regulator reminded mine operators that they should have systems in place to maintain brake systems functionality.

It said truck operators must be trained and deemed competent in the use of braking systems, including in emergency situations.