Horizontal directional drilling
- roads,
- pavements,
- protected green spaces,
- railway tracks,
- rivers,
- drainage ditches,
- and other watercourses.
The process has three stages:
A drill head with a steering plate and locating probe enters the pilot bore at the required angle. Additional drill rods are connected as the head advances. An electronic locator tracks the probe in the drill head, allowing the operator to follow the planned bore path.
Once the pilot bore is complete, the drill head is replaced by a reamer selected for the ground conditions and required diameter. The reamer rotates as it is pulled back, widening the bore. Specially prepared biodegradable drilling fluid carries away the excavated material and stabilizes the bore. Larger diameters are achieved in stages using progressively larger reamers.
The prepared pipeline is attached to a pulling head and drawn into the enlarged bore. For smaller diameters, reaming and pipe installation can sometimes be completed in the same pass.