A joint venture consisting of Tru Energy and Nacap Australia was engaged to install a new 272mm steel gas main spur from the Eastern Gas Pipeline, in order to to feed the new 400 MW gas fired power station being constructed by Tru Energy at Yallah. A section of the pipeline was required to be installed under the F3 freeway, the Illawarra rail line and a number of creeks. In some places the depth would exceed 28 metres to avoid bridge piers.
UEA utilised its 300,000 pound HDD rig for this project and the Paratrak 2 system for locating the bore. This enabled real time monitoring of the bore profile and ensured the bore was not compromised at any point.
Throughout the pilot bore the ground conditions varied in consistency, so a good mud plan was developed and adhered to throughout the operation. A hole-opener with 16 inch medium formation cutters was used to forward ream the 700 metres of rock. Once the rock section had been completed the drill rig was re-mobilised to the exit side where it proceeded to forward ream the clay section.
As part of the process for bore hole approval UEA was required to pull a section of dummy pipe approximately 36 metres long. Once the pipe had been pulled in it was inspected for damage and tested. The dummy piece was unscathed and the client approved the installation of the new pipe.
The 763 metres of gas pipeline were placed on rollers in preparation for pullback to reduce friction during the process. Throughout the pullback process the pipe coating was tested to ensure its integrity.
For more information about this project or UEA Trenchless, please send enquiries to Steven Hopkins.