Working principle and explanation of down-the-hole drill

A down-the-hole drill, usually called DTH by most professionals, is basically a jackhammer screwed on the bottom of a drill string. The fast hammer action breaks hard rock into small cuttings and dust that are evacuated by a fluid (air, water or drilling mud).. A down-the-hole drill, usually called DTH by most professionals, is basically a jackhammer screwed on the bottom of a drill string. The fast hammer action breaks hard rock into small cuttings and dust that are evacuated by a fluid (air, water or drilling mud).. In down-the-hole drilling a drill rod is fitted with a hammer at its lower end. The hammer, which is mounted on the drill bit, is activated through the addition of compressed air and driven into the ground – simultaneously rotating and impacting.. Down-the-Hole (DTH) drilling is a technique used to create deep, precise holes in hard rock and challenging ground conditions. In this method, the hammer and drill bit are placed at the bottom of the drill string, directly engaging with the rock. [pdf]