Page 35 - PENYIASATAN TAPAK

3. METHOD OF ADVANCING BOREHOLE

• Rotary boring

• Rotary boring involves a hollow rod with drill/cutting bit attached at the

bottom

• The dislodging of material below the rod is achieved by rotary action of the

drill rod under hydraulic thrust and cutting action of drill bit.

• The hollow rod carries water or drilling fluid down to a drilling/cutting bit at

the bottom of the rod.

• Almost all water or drilling fluid through the cutting bit is discharged into soil
sideways rather than vertically, thus disturbance to soil directly below the rod

is minimized.

• The cuttings, thus dislodged, are transported to the ground by drilling fluid

outside of the drill rod but inside the casing.