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The general term 'drill rig' covers several differing types of machines for use in the construction industry,
water well drilling industry, mining and quarrying, for use above ground as well as underground and for
tunnel construction. The differing tasks determine the choice of drilling method and type of machine. For this
reason there are many possible ways to separate drill rigs into different groups, e.g. in accordance with:
- the task;
- the drilling method used;
- the cutting removal method;
- the type of construction work.
The methods used for drilling can be basically differentiated in percussive and rotary drilling
principles. Percussive drilling is a method by which the hole is produced by crushing the ground or rock at the
bottom of the drill-hole by striking it with the drilling tool and removing the cuttings out of the borehole.
Rotary drilling is a method in which the drilling tool at the bottom of the borehole is rotated and at the same
time, a feed force is applied by a feed system or drill collar. The ground or rock at the bottom of the
borehole is crushed or cut by pressure, shear or tensile stress produced by the different drilling tools. The
of the bore hole.