Down Hole Hammer
The down-the-hole hammer is essentially a pneumatic jack hammer that screws on the bottom of a drill string. The fast hammer action breaks hard rock into small flakes and dust and is blown clear by the high pressure air exhaust from the hammer. The DHH is one of the fastest ways to drill hard rock. Air exhaust is directed through a manifold at the surface into a cyclonic hopper drill cuttings can then be collected into drums for disposal.
Water can be injected via a high pressure water pump into the air stream to totally control dust emissions. Water injection can make it harder to determine exact groundwater intersections.
When ground water is encountered it flows into the exhaust air stream and into cyclonic hopper.
Once target depth is reached hammer and rods are removed and well installed in open hole.