An explosives contractor conducted the blast. After loading the drill holes, the shot-firer walked towards the firing point, about 150 metres from the blast site, unwinding the bellwire. There was no line of sight to the blast site. The explosives company moved vehicles to other points in the quarry. The driller walked the drill rig away from the blast site.
The quarry blast procedure checklist was worked through. A quarry employee gave the ?all clear? and drove to a safe point to film the blast. The quarry control room was advised that the checklist was complete and it was ?okay to proceed?. The blast siren was sounded.
The shot-firer was then contacted. A visual check was conducted, final firing connections undertaken and a final radio communication occurred 10 seconds before the blast. Unknown to the shot-firer, the driller had returned to the drilling company utility after shifting the drill rig and at the time of initiation was 20 to 30 metres from the blast. Despite his proximity in the cab, no injury occurred and there was no damage to the vehicle.
CONTRIBUTING FACTORS
Workplace Standards Tasmania concluded from the episode that:
- The driller was not signed in at the quarry entry point.
- The traffic management plan and exclusion zones for the quarry were either not followed or were inadequate.
- The shot-firer commenced the final blast preparation procedure before ensuring all personnel/vehicles were outside the exclusion zone.
- The on-site communication procedure was not followed.
- The explosives company communicated the ?all clear? and ?OK to proceed?, not the quarry.
ACTION REQUIRED
Workplace Standards Tasmania recommended that for future blasts:
Workplace Standards Tasmania recommended that for future blasts:
- All personnel (contractors included) must sign in.
- At a site with heavy vehicle usage, traffic management must be incorporated in the blasting plan.
- Sentries should watch and bar access to the blast site.
- Under Tasmanian mine safety laws, quarry personnel should communicate the ?all clear? and ?OK to fire?.
- Shot-firers must ensure the exclusion zone has been vacated completely before commencing the final firing procedure.
- On a quarry site, the warning siren used should be loud enough to give adequate warning to those likely to be affected by the blast.
Under Section 15 of the Dangerous Substances (Safe Handling) Act 2005, Discharge of Obligations (Tasmania), contravention of a safety obligation that causes death or serious personal injury may lead to a fine of up to $780,000 or imprisonment of up to three years.
Source: Workplace Standards Tasmania