Blast Hole Drill Rig


Picture by: Joe Nale

Here's an interesting picture of a drill rig, drilling blast holes ahead of the dragline. Blast holes are typically about 15 inched in diameter and can be up to 60 feet deep. Once all of the holes are drilled, and the rig is out of the way, the holes will be loaded with a powdered explosive mix, and then shot. This fractures the rock, and makes it easier for the dragline to dig.

The dragline ( A Manitowoc 6400) can be seen working in the background here, along with a dozer which is preparing the bench for the drag to sit on. Notice how the farthest row of holes lines up with the highwall in the background.