Our Rock Drilling process utilises a concentric system, which simultaneously drills the rock with a down the hole hammer whilst installing a steel pipe. This means that the bore is sleeved at all times, so the risk of losing the bore due to broken, collapsing rock is eliminated - this being a problem sometimes encountered using an open-hole system.

Due to the fact that the Concentric system sleeves the bore as it drills there is no open void created at any time, which offers greater security to railway lines and rail traffic. The steel sleeve gives stability to the drill as it progresses and prevents deviation.

The rock-drilling hammer, with the pilot bit attached, is driven by an Auger Boring rig and powered by air. The ring bit with internal bayonet coupling is attached to the steel pipe using a casing shoe. The pilot bit is attached to the ring bit with bayonet coupling.

Both rotate clockwise and together cut the hole, which is sufficiently large enough to allow the casing shoe to pull the steel pipe. The ring rotates freely on the casing shoe, which is welded to the first casing pipe. During drilling the steel pipe does not rotate.

Rock Drilling Images

Advantages of Rock Drilling

· Cost Effective solution to rock or boulder crossings
· Straight & Accurate bores
· Fast & Reliable in adverse ground conditions

Further information on Rock Drilling Services by Dunnes Drilling