Boring the Cut
When the clean-up is complete we can start to bore the lifters. The lifters are the bottom row of holes in the cut and lift the rock up as they are fired last.
The bogger comes in to do the clean up once the jumbo finishes bolting because during the bolting process loose rock is bought down off the backs (roof), walls and face (the wall that we are drilling into). The lifter holes are bored first so the fines (cuts of rock from the drill) don’t fill them up as the rest of the face gets bored. We place lifter tube into the holes. Lifter tube is 45mm poly pipe that is inserted into the bored holes. Then the perimeter holes and the infill holes. These are the holes around the outside of the cut. Lastly, comes the ‘byrne’ and reamers to complete the cut. The reamers are the large holes in the Byrne that are not charged with explosives. This is the weak spot that allows the rock, the space to move. Once it cracks back to the reamers the rock has nowhere to go except out back down the drive.