How does DTH work?

It can be done on both hard and soft rock and is extensively used in the construction, oil and gas, and water well industries. DTH equipment consists of a drilling hammer and a piston-powered by compressed air. As the drill string rotates, the drilling hammer strikes down on the rock.

What is a DTH drill?

DTH is short for “down-the-hole”. Since the DTH method was originally developed to drill large-diameter holes downwards in surface-drilling applications, its name originated from the fact that the percussion mechanism followed the bit down into the hole.

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

Down-the-hole drilling (DTH) essentially involves a drilling hammer at the bottom of a drill string. It relies on three elements for drilling holes: bit loading (weight), rotation and air. These active elements combine to be efficient at crushing rock. As the drill string slowly rotates, the drilling hammer is forced into the rock repeatedly.

How does DTH drilling work?

DTH drilling is most suitable for hole diameters of 4–10 inches, with some exceptions. The DTH hammer is pneumatically powered, with the compressed air propelling it forward to impact and fracture rock. Compressed air also travels through the drill bit into the hole (air exhaust), which blows the chips and dust out of the hole.

Is DTH a good drilling method?

DTH is a reliable method that drills stable holes with exceptional straightness. The method is also excellent both environmentally and socially because it produces far less noise and vibration than many other drilling methods, making it a widely used drilling method in cities and other populated areas.

What makes a DTH drill system different from other drilling systems?

The advent of tungsten carbide for the drill bits (the first bits were all-steel) and the development of the button drill bit coupled with the introduction of high air pressures (25 bar plus) has meant that the DTH system can compete easily and efficiently with other drilling systems.