Blast Safety: Exclusion Zones, Misfires and Emergency Procedures
Every shot requires a defined danger/exclusion zone sized for the blast design, the environment and the potential for flyrock. The zone must be cleared and guarded before firing; sentries, barriers and audible signals control access. The shotfirer confirms all persons are clear, gives the warning signal, fires, and gives the all-clear only after inspection. Communication must be reliable and agreed in advance.
A misfire is a charge or part of a charge that failed to detonate as designed, or a suspected one. The response is disciplined: keep everyone out, maintain the exclusion zone, wait the specified time, and then investigate under the site's written procedure, usually with the shotfirer in control. Never re-enter to "have a look" or attempt to re-fire a misfire without following procedure. Misfires must be recorded and reported.
Emergency procedures cover fire, premature explosion, lightning, and injury; know the site's alarm, first-aid and evacuation arrangements. Traps include treating a "cut-off" as a simple misfire, and assuming the all-clear can be given from a distance without inspection.
Rule of thumb: no inspection, no all-clear. The exclusion zone stays until the shotfirer has inspected and declared the area safe.
Worked example: after firing, one hole shows no movement and no smoke. The shotfirer keeps the zone closed, waits the specified period, then inspects and follows the misfire procedure, recording the event.