January 2018, Vol. 245, No. 1
TechNotes
Pipeline Connection Installed in Australia
The drilling rig is 250 tons of pulling force led to early completion of a complex project.
In just three months, Australian drilling contractor Dunstans Construction Group installed a 35-mile (700-meter) pipeline in Anglesea, and a 250-ton HDD rig from Herrenknecht played a key role in the achievement. The construction crew built a sea outfall with the machine and pulled in the pipeline all the way back to the local water treatment plant.
In August 2015, a large cliff segment collapsed in the Australian state of Victoria, resulting in an acute need for action. Falling rocks massively impaired the sea outfall pipe of the local water treatment plant on the Bass Strait Coast. The affected sewage pipe had to be replaced as quickly as possible to ensure stable wastewater disposal. The targeted timescale for the operation was tight. completion of the new infrastructure in three months as Christmas neared.
The protection of nearby Point Addis Marine National Park played an additional role in the installation of the new pipeline using the sea outfall method. To meet the strict environmental protection requirements, the Australian drilling contractor counted on technology from Germany. Dunstans ordered a Herrenknecht HK250C HDD rig, a technology that previously demonstrated its effectiveness in sensitive environments on numerous occasions.
For the installation of the polyethylene (HDPE) pipeline with an outer-diameter of 14 inches (355 mm), the crew first drilled a pilot hole under the sea from the treatment plant to the coast. Then, the borehole was reamed from the land side.
After completion of the borehole Dunstans overcame another hurdle when it transported the product pipe by sea, past Port Philip Bay, one of the busiest ports in Australia. Regular shipping was not obstructed by the exceptionally long cargo.
To complete the installation Dunstans pulled the pipeline floating on the sea through the predrilled alignment all the way back to the treatment plant. Thanks to the 250-ton pulling force of the HDD Rig the job was carried out quickly and cleanly. With the connection of the pipeline to the treatment plant completed before Christmas, Anglesea was ready for the tourism high summer season.
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