Down-the-Hole (DTH) Drilling


Down-the-Hole drilling is one of the fastest, most dominant methods of geotechnical drilling. DTH drilling has many applications, including water well, oil and gas, blast hole and foundation drilling. This is an energy efficient form of wide-hole drilling (in the hole range of 100-254 mm) that can be performed in both a downward and an upward direction.

DTH drilling does not require guiding equipment, yet results in straight holes within a deviation of 1.5%. DTH drilling breaks down hard rock through the hammering action of a DTH hammer drill bit attachment. The small rock particles created by the drilling rig are blown from the borehole by the DTH hammer air exhaust. Drill pipes provide compressed air, feed force and rotation for the hammer, and are added on along the drill string as the hole deepens.

In DTH drilling, direct striking of the piston on the bit and the guiding action of the hammer casing keep the drill bit straight and stable. This results in constant energy on the impact surface, regardless of changes in hole depth.

DTH drilled casings are one of the most common methods for foundations, reinforcement work, water well drilling and metropolitan work (i.e. bridges, utility lines, and building construction). The development of DTH drilling and the introduction of special drilling systems like Symmetrix have refined overburden casing systems and encouraged the utilization of new construction methods. DTH drilling is an efficient, multipurpose drilling system that saves both time and money.

  • Auger drilling 4-12 inch augers
  • Hollowstem 4 ¼ - 12 ¼
  • SPT (Standard Penetration Test)
  • Direct Push (Dual Tube) 2.5-4.5
  • DTH (Odex) 130mm
  • Air Rotary 4.5 - 12inch
  • Core Drilling
  • Laskey Coring
  • Shelby Tubes
  • Piezometers
  • Inclinometers