Flyrock Incident During Blasting

By on October 4, 2017

Flyrock Incident During Blasting

This information is to assist operators and workers to understand their duties and responsibilities in relation to Safe Distances when using explosives and should be read in conjunction with;

An extract from the NSW Resources Regulator –

Flyrock incident at open cut coal mine (31 July 2017) is given below.


Workers were at risk of being struck by flyrock when they remained in an exclusion zone during blasting at an open cut coal mine. Flyrock from an overburden blast struck a light vehicle near the
workers. The flyrock damaged the bonnet and front grill of the light vehicle. No workers were struck by the flyrock. At the time of the shot being fired the workers and light vehicle were positioned
at the firing location about 246m from the blast area. The mine’s blasting procedures required an exclusion zone of 300m for mobile plant and equipment and 500m for workers. The NSW Resources Regulator has commenced an investigation into the incident.

Investigation information release on a serious incident

SITE PHOTO: Damage to bonnet and front grill of light vehicle caused by flyrock

The incident

On 17 May 2017 at about 12.07 pm, an overburden blast occurred at the Moolarben No. 4 Open Cut. When initiated the blast projected material, known as flyrock, beyond the boundaries of the
blast area. At the time of the blast, six workers and light vehicles were positioned at the firing location which was approximately 246m from the blast area.

As the flyrock began falling to the ground some of the workers took cover while others attempted to visually observe, track, evade and warn others of the flight path of the flyrock. Flyrock landed and struck one of the nearby light vehicles damaging the bonnet and front grill. No workers were struck by the flyrock. After the flyrock fell to the ground the workers relocated themselves and the vehicles from the immediate area due to dust and fumes produced by the blast.

The mine had written blasting procedures in place that prescribed exclusion zones of 300m for mobile plant and equipment and 500m for workers during blasting.

Early information suggests the flyrock was ejected from a single shot hole. The most likely cause was under- stemming, potentially caused by bridging of the stemming, but other potential causes will be examined during the investigation.

The investigation

The Resources Regulator has commenced an investigation into the incident. The mine operator is cooperating with the investigation. An investigation report will be prepared for the Secretary of the Department of Planning and Environment.

Safety observations

Mine operators are reminded of their duty to identify hazards and manage risks to health and safety associated with explosives and shotfiring activities in accordance with the provisions of the Work Health and Safety Act 2011 (NSW), Work Health and Safety (Mines and Petroleum Sites) Act 2013 (NSW) and regulations.

There is specific legislation about the management of risks associated with explosives. Persons conducting business or undertakings should be aware of clauses 26 and 31 and Schedule 2 of the Work Health and Safety (Mines and Petroleum Sites) Regulation 2014.

Mine operators must ensure that appropriate information, instruction and supervision is provided to workers in relation to exclusion zone requirements prescribed within the mine’s
explosives control plan.

Mine operators are reminded that appropriate systems must be in place to review and audit the explosives control plan and blasting work practices to ensure that exclusion zone requirements are enforced.

About this information release

The Resources Regulator has issued this information to draw attention to the occurrence of a dangerous incident in the mining industry. Investigations are ongoing and further information may be published as it becomes available.

The information contained in this publication is based on knowledge and understanding at the time of writing. However, because of advances in knowledge, users are reminded of the need to ensure that the information upon which they rely is up to date and to check the currency of the information with the appropriate officer of the Department of Planning and Environment or the user’s independent adviser.

Go to to:
• learn more about our work on major investigations and emergency response
• view our publications on other major investigations
• find your local mine safety office, where you can contact our team of mine inspectors.

CMPA will provide further information on exclusion zones in the next issue of Sand & Stone.


About Gavin Moreira

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