Although no one was injured in the incident, the car was damaged and the potential for harm was high, the Queensland Mine Inspectorate said in a Safety Alert.

“With four fly rock incidents in the past year, some sites may not be correctly calculating exclusion zones and/or recording this information on scaled aerial maps, even when exclusion zones are referenced in the sites’ Blast Management Plans,” it said.

To reduce the potential for fly rock incidents, the inspectorate recommends considering the size, geological nature, shot location and site topography as well as the hole diameter, depth of charge and burden when determining an exclusion zone, using additional blanketing material when necessary.

The potential throw direction of the blast, potential for fly rock, potential impact on public and private roads, infrastructure and neighbours, their plans and locations should also be considered.

Furthermore, well controlled blast exclusion zones should be established around each blast and exclusion zones should be cleared of personnel before firing.