What happened?
During a night shift inspection of a sleeping shot, it was identified that a single blast hole had initiated. There was previous evidence on the bench of heating at a blast hole collar when a downline was severed while resting on coal stemming. No persons were in the vicinity at the time of the initiation.
Recommendations
The physical characteristics and potential hazards, which may be associated with the characteristics of the material to be blasted, should be identified and assessed.
In reactive or hot ground situations, it is not advisable to use drill cuttings that are reactive as stemming material. During drill and blast preparations, operators should be aware of issues that may occur and take appropriate action.
In reactive or hot ground, sheathing of ANFO explosives or other measures to inhibit exothermic reactions between the explosives and the material to be blasted may be necessary.
In the case of reactive or hot ground, the explosives to be used and the charging practices to be adopted should be developed in conjunction with explosives manufacturers, explosives consultants, or other expert authorities using the risk management process to take appropriate mitigation.
Geological review and sign off, on all blast designs should be conducted.
Investigations are ongoing and further information may be published as it becomes available. The information in this publication is what is known at the time of writing. We issue Safety Notices to draw attention to the occurrence of a serious incident, raise awareness of risks, and prompt assessment of your existing controls.
Authorised by Noel Erichsen - Chief Inspector of Explosives
Contact: explosives@dnrm.qld.gov.au
Issued by Queensland Department of Natural Resources, Mines and Energy