What is a down-the-hole drill?

A down-the-hole drill, usually called DTH by most professionals, is basically a jackhammer screwed on the bottom of a drill string. The fast hammer action breaks hard rock into small cuttings and dust that are evacuated by a fluid (air, water or drilling mud). The DTH hammer is one of the fastest ways to drill hard rock.

What is down-the-hole (DTH) drilling?

Down-the-hole (DTH) drilling has made it easier for contractors to drill wells faster and more efficiently, and to transition from dirt boring to rock boring just by adding a compressor and hammer to the drill bit.

What is a DTH drill rig?

A down-the-hole drill, usually called DTH Drilling Rig, is basically a mini jackhammer screwed on the bottom of a drill string. The speedy hammer activity breaks hard stone into little flakes and dust and can be dismissed evident by the air exhaust in the DTH hammer.

How long did it take to drill a 12,000 ft hole?

The original estimate for completion of a 12,000-foot hole was 30 days using the conventional rotary technique, which was reduced to 13 days using the DTH method. Before DTH was used, drillers would typically case the vertical portion of the well and convert to rotary drilling to drill at a tangent.

How was a hole drilled?

This system could not guarantee a finished hole size and only pure vertical holes could be drilled as the system basically relied on gravity. Debris from the hole was baled out using a baling tube with a clack valve, which was periodically dropped on a winch to capture the slurry, which was then brought to the top of the hole to be discharged.

How does a drill work?

This action along with the rotational movement of the drill string crushes the rock efficiently. Since the piston strikes directly on the bit, energy transfer takes place down the hole with minimum loss of energy, allowing drilling to greater depths. The driving medium i.e. compressed air is also the flushing medium.