Blast Control ; Flyrock Incident

Information:

What

During a quarry blast under the control of a contractor, flyrock was projected more than 500 metres onto the Pacific Highway. A rock of approximately 100mm diameter was also projected onto a nearby property where it caused damage to a shed and parked vehicle.

Why

During loading the contractor expressed some concern that a number of holes were Getting Away On Them. The theoretical loading of the 12 metre holes was 80kg of explosives with a 2 metre stem height. In 9 holes, 90kg of explosives were used without achieving the stemming depth, possibly due to leakage through fissures in the rock mass. This was consistent with the geology of the pit.

Recommendations

Where there is a potential for the explosives to run through the cracks in the rock mass, a procedure should be followed to deal with the loss of explosives. etc

Organisation:

NSW Department of Primary Industries

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Jurisdiction:

Relates to New South Wales (NSW)

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