NZMIA > resources for schools > industrial minerals > limestone case study

Limestone may be just the skeletons of millions of ancient sea shells, but you can't just load it onto a truck with a shovel. First it has to be blasted loose from the surrounding rock

In preparation for the blast the face is bored and explosives are packed into the drill holes. The pattern of the holes and the sequence in which the holes are detonated determines the shape of the blast and so the way in which the rock is loosened and broken up. In these pictures you can clearly see where the explosives have been placed. Because this limestone quarry is in a secluded rural area the blasts can be quite large by New Zealand standards. Most blasts in quarries and mines are smaller.

Before the blast all work stops. The quarry is cleared. Roadblocks are put up. Spotters are placed in strategic positions. A siren sounds as a final warning. The countdown begins...

blasting

After the blast the all clear siren sounds and the area is checked for any loose overhanging rocks or other dangers. Once the area is designated safe the loaders and trucks move in.

mcdonald's lime ltd

This information has been compiled with the help of McDonald's Lime Limited

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