Horizontal Directional Drilling (HDD)
Pipe /Cable – laying by Horizontal Directional Drilling (HDD) is one of the most innovative construction methods today.
Technology overview and benefits
Directional borings are fast and have the least environmental impact of any alternate method.
HDD Method Statement
Our HDD works can be divided into 3 independent stages, namely:
1. Pilot bore:
The pilot bore is the rst phase in any HDD project. The pilot bore is executed by directionally guiding the drill head along a determined path from entry point (rig side) to the exit point (pipe side).
Machinery utilized for drilling the pilot bore in hard rock conditions are available and includes the R.A.T.T (Rock Adaptable Terrain Tools) to penetrate into hard rock conditions.
Pre-Reaming is done with the same machine as the machine that was used for drilling the pilot bore. Once the pilot bore is completed the drill head and tracking system is disconnected from the drill string and back reamers are installed. Back reaming is usually performed in stages until the nal desired diameter of hole is reached, hence the pipe is ready to be pulled.
3. Pipe pulling
Pipe pulling is the last phase before the job is done. The pipe is connected to the drill string and it is then pulled from the exit pit side towards the entry pit side (rig side).