If you could ask one hundred drillers what their favorite type of drilling was, I would bet that ninety-five of them would answer hammer drilling. It’s a ‘guy thing’ on at least three levels:
- It’s fast,
- It’s powerful and loud,
- and it makes a bunch of money.
—– Insert here Home Improvement’s Tim Taylor grunting ——
But the $5,000 to $25,000 question is, “Is hammer drilling the best way to drill your well?”
The average air hammer for a 6.5” hole is about 5 feet long, weighs about 300 pounds, and costs somewhere around $5,000. A large compressor on the drill rig creates 350 PSI of air at 750 CFM. Down in the bore hole, the air hammer has a piston inside of it that cycles up and down very fast and hits the top of the drill bit which then transfers the force of each of the hits to the virgin rock. The air hammer is at the end of the drill rod that rotates and allows high pressure air and a small amount of water is forced through the hollow drill pipe to create the energy for the hammer and to also remove the cuttings from the hole. There are carbide bits or tips on the face of the drill bit. The bit hits the ground every fraction of a second while the rotation of the drill string (drill pipe and hammer) places the carbide tips where they can have fresh rock to strike and shatter. The used air and water and sometimes foam then takes those small particles of rock (cuttings) and pushes them away from the hammer face and up through the bore hole to the surface where the cuttings are discharged onto the ground.
If you have hard rock like sand stone or granite in our area, well God bless you. You need to have a well hammer drilled. This is really the only way to get a hole in hard rock. You folks in North Durango have some seriously hard rock that requires us to purchase the hardest carbides that the industry has to offer – and a 600′ hole will still cause a lot of wear. The upside about hammer drilling is that normally the bore hole is very stable. When a driller reaches water, he can spend some time and air lift the water and ‘clean’ the borehole and determine roughly how much water you have without fear of the borehole collapsing. All of us in the well drilling business love to drill hammer holes.
But let’s go back to the high dollar question. Is hammer drilling right for your ground? If you have shale or clay ground material you need to read the next page: Low Pressure Foam Drilling.