- Percussion drills
-
Rotary drills - The rotary drills can be further grouped into -
- Pressure drilling
- Abrasion drilling
Also, various types of augers are used for earth drilling.
-
Percussion drilling - A percussion drill breaks rocks into pieces by the impact from repeated blows. Sometimes, compressed air or hydraulic fluid can power percussion drills. It may be combined as rotary and percussion. It generally employs a reciprocating air operated hammer with impacts a rotating bit or a spring of rotating drill with bit on its bottom.
-
Rotary drilling - In the rotary drilling, the drilling is carried by applying a down pressure and at the same time continuously rotating the bit in the hole. This type of drills can be mounted on a truck or crawler tracts. These drills are suitable for drilling soft or medium rock.
|
|