Anglesea, Australia, July 5, 2016. 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 3 months, i.e. by Christmas.
For the installation of the polyethylene (HDPE) pipeline with an outer diameter of 355 mm (14 inches) the crew first drilled a pilot hole from the treatment plant to the coast and under the sea. Then, the borehole was reamed from the land side. After completion of the borehole Dunstans overcame another hurdle presented by the project: transporting the 700 m long 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.
- Project: Anglesea Outfall Replacement
- Borehole length: 700 m
- Product pipe outer diameter: 355 mm
- Product pipe material: HDPE
- Application: Sewage
- Geology: Mudstone
- Customer: Dunstans Construction Group
- Client: Barwon Water
- Machine type: HK250C HDD Rig
- Pulling force: 250 t
- Torque: 90 kNm