A dump truck was reversing to a tip head when it breached a windrow, with two wheels going through the windrow.

No-one was injured.

"Ground stability should be considered when planning a dump site," the regulator said.

"Mine operators should review how their supervisors monitor critical controls and determine what actions to take when critical controls are identified as being inadequate."

The regulator said tipping procedures should be reviewed to ensure that dump trucks do not tip close to edges.

"Dumps should be maintained in a straight line, with windrows constructed of predominantly dry, competent material to a specified height," it said.