DTH Hammer Drilling Operation

How To Collar The Hole

1) Feed the hammer down ward until the drill bit is about 5 cm from the collaring point.

2) Start rotation to the right at low speed

3) Feed the hammer on to the rock using minimal feed force, so that the bit is pressed into the hammer, and into the impact position.

4) Start collaring the hole

with reduced impact and feed, until the bit has entered the rock.

5) Open the impact mechanism control fully and adjust the rotation and feed so that the hammer drills smoothly and steadily.

Always Rotate To The Right

DTH hammers must always be rotated to the RIGHT during drilling (clock wise), even when the hammer is not operating. Rotation to the right should be switched on as long  as other operations are in progress with the hammer in the hole.

When breaking the joints between drill pipes, bear in mind that the drill string must not be rotated anticlockwise any more than is absolutely necessary.

Left-hand rotation (or no rotation) will cause the driver chuck to loosen, which could mean losing the drill bit (or even the entire hammer) down the hole.

Remember:

• Always switch on rotation to the right before starting the feed or hammer.

• Let the hammer rotate to the right (clockwise) even during lifting or lowering of the hammer.

Do not switch off rotation to the right until all other functions have been switched off.