John Holland has completed tunnelling for New South Wales’s Belmont Desalination Plant and retrieved the micro TBM from the sea floor.
TBM Rhiannan bored an 830m-long seawater intake tunnel and installed the 2.4m-diameter pipeline beneath the seabed for the Hunter Water project.
Recovering the 11.5m-long machine marked the completion of one of the most complex and high-risk components of construction on the A$530m (€323m) plant.
The recovery followed a carefully planned sequence of offshore works carried out over several weeks.
Specialist divers first removed debris from around the machine before positioning and aligning a support cradle to guide the TBM into place ahead of retrieval.
The divers then connected the hydraulic recovery system, allowing the 75-tonne machine to be pushed clear and prepared for lifting. The lift was completed by positioned on an offshore jack-up barge.
With tunnelling completed, the focus now turns to the installation of mechanical and electrical equipment and ongoing works to connect the seawater intake structure to the treatment plant.
The plant, situated near Newcastle, will be capable of producing up to 30 million litres of drinking water a day, enough to meet around 15 per cent of the region’s average daily demand.
Hunter Water managing director Jennifer Hayes said recovering the TBM from the seabed was a significant achievement and reflected the technical expertise, planning and teamwork required to deliver project.
“This milestone brings us another step closer to delivering a climate-resilient water source that will help strengthen water security for the Lower Hunter.
“The Belmont Desalination Plant is a key part of the Lower Hunter Water Security Plan and will help ensure our region has a reliable source of drinking water during future droughts and changing climate conditions,” she said.
TBM Rhiannan was named after Belmont local and world champion cliff diver Rhiannan Iffland.
As well as the intake the pipeline, the desalination plant project includes a new water treatment plant, two news water mains and upgrading existing reservoirs to integrate desalinated water into the network.
