A fire at an underground explosives magazine at a South Australian mine has prompted a safety warning to operators about the storage and handling of blasting materials.
Inspectors from SafeWork SA attended the site last year after a fire broke out in the underground magazine during a shift change.
According to the body, the magazine’s deluge system activated automatically, while the site’s Emergency Response Team (ERT) and the magazine keeper responded to the scene and confirmed the fire was extinguished with no injuries reported.
SafeWork SA investigation into the incident has since identified that several blasting cartridges that had been damaged and were leaking a black substance from their casing.
The product’s Safety Data Sheet states the explosive composition may auto-heat when exposed to humid conditions. The humid environment in the underground mine may have contributed to heat generation through the exothermic decomposition and reaction of the explosive material, according to SafeWork.
Investigators determined the most likely cause of the fire was the auto-heating of explosive substances leaking from the damaged cartridges, which ignited either the explosives themselves or the surrounding carton.
Following the incident, SafeWork SA is urging mine and quarry operators to ensure explosives are stored and managed in line with manufacturer guidance and safety documentation.
The regulator is advising operators to keep explosives within their recommended shelf life and to put clear plans in place to safely destroy expired materials as soon as reasonably practicable.
Operators should also store explosives according to the temperature and humidity requirements outlined in Safety Data Sheets or Technical Data Sheets, and ensure blasting cartridges remain in cartons that are closed and sealed.
SafeWork SA also urged operators to quarantine damaged explosives away from other materials and destroy them promptly.
The regulator further advised explosives users to maintain whole-of-life management plans for explosives and security sensitive ammonium nitrate (SSAN), including clear procedures for dealing with materials that are expired, damaged or otherwise out of specification.
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