The "DTH" is the abbreviation of "Down The Hole" and sometimes it is also called "RAB" in some markets, and the "RAB" is short for "Rotary Air Blasting".
A rotation drill rig, air compressor and the "DTH drill string" are the essential unit for DTH drilling while the "DTH drill string" is always made up of DTH drill rods, DTH hammer and DTH bits. As one of key component, the DTH hammer acts as a role of converting the air pressure to the impact energy, simultaneously transferring impact energy and rotation force to DTH bits