Idle hours after a blast: what the charts usually show
On several limestone pits we have watched, the blast window itself is short. The longer idle sits in the hour that follows. Loaders wait for the shotfirer to walk the muckpile. Trucks queue because nobody wants to be the first to approach a high wall that still has loose. Those minutes look like “low utilization” on a monthly summary, yet they are the correct safety practice.
When we chart those hours, we keep them in a separate delay class: post-blast hold. Mixing them with mechanical breakdowns makes the workshop look worse than it is, and it invites the wrong kind of pressure on the blasting crew.
A useful conversation is whether the first load after the hold is delayed by the road, the crusher, or the face. Walking that hour with the shift boss, rather than reading only the summary, usually answers it. The chart then becomes a record of that walk, not an accusation.