Auger Boring

rotary drilling with a rotary-blade drill bit, in which the broken rock is removed from the cutting face by means of a screw conveyor. The rock is broken up by steel or hard-alloy cutting tools (sometimes replaceable types), which rotate at 100–240 rpm and are pressed against the face with a force of 300–2,000 kg by a drilling strut composed of the augers. Auger drilling is used to drill shot holes in fairly weak rock (less frequently, to sink holes with the aid of a drill) and to sink shallow hydrogeological and engineering-geological wells. Drilling productivity ranges from a few meters to hundreds of meters per shift. Pneumatic auger drilling is currently being tested. The technique uses compressed air, which is fed into the spiral of the auger and which partially suspends the particles of broken rock moving through the auger, thus facilitating removal of the rock from the well.