In the fall of 2022, Brownline Australia surveyed an HDD crossing under the Yarra River. Three-quarters of the HDD’s length took place under the bed of this wide river.
Contractor AHD Trenchless carried out this HDD crossing, which serves to install telecommunications cables under the river. By using the Drillguide Gyro Steering Tool, the progress of the pilot bore could be tracked very accurately.
Tight exit window
Underneath the middle of the busy river, a horizontal curve was made and after 400 m / 1300 ft, the drill resurfaced on the other river bank. The vertical curve that was needed to reach the exit point was very sharp, because there was little space between the river bank and a nearby road. Using Brownline’s GPS track, an extra verification was carried out. This allowed the drill to punch out very accurately within the tight margins.
By using a Drillguide Gyro Steering Tool on this crossing, disruption to the surrounding environment was kept to a minimum, and likewise, the pilot drill also was not influenced by outside interference.
After the success of this crossing, more pipelines were installed under the Yarra River, using the Gyro Steering Tool to guide the pilot bores.