Then the drilling team drill the holes for the explosives. Each hole must be carefully checked. It must be the right depth and in the right place. This is a long and tedious job. The drilling team have about 200 holes to drill on each blast floor. That's over 800 holes to check and double check. The drills are very noisy. The drillers have to wear special muffs to protect their ears. And so much I. Sometimes I feel like my head's about to split open.