LASER-guided microtunnelling is being used to bore 2.3km horizontally and hit a target within 2cm of tolerance – and what’s at stake is 1.5 million litres of sewage a day.
The use of the technology, believed to be a first for Tamworth, is in the regional council’s $2.5 million sewer rising main project.
And this week, the project’s focus turned to the levee bank at the northern end of Peel St.
Previously: Bridge to close for sewer works
Contractors started boring under the bank from the river side to the street side, and from the rear of Tamworth Community College towards Jewry St.
Tamworth Regional Council’s water projects and services manager, Mick McGufficke, said these were “critical works”.
“We’ve reached a fairly important stage of the project,” he said.
“It’s some technology we don’t use very often, requiring a high level of tolerance over a long distance … Because of the nature of this project, we had to step up the technology that we’re using to make sure we achieve the outcomes of the project.”
‘It’s gotta go right’
The project is replacing some 50-year-old infrastructure with new, relocated pipes to avoid possible issues from upcoming road projects and increased traffic.
The pressured pipe system carries 1.5 million litres of sewage a day from the Darling St Pump Station to the higher Swan St Pump Station.
Mr McGufficke said this stage of the project would take two to three weeks, but there “shouldn't be too much in the way of interruptions to pedestrians or traffic”.
“They may notice some works along the edge of Manilla Rd and some traffic control, but there remain two lanes open,” he said.
“The cycleway and path on top of the levee will remain open, so we’re expecting minimal interruptions and we’ll try to maintain that as best we can.”
Mr McGufficke said the overall project would reach another crucial point in just over a month.
“Around the middle of December we’re expecting to have a fairly critical stage where we’ll have all night works … we expect to have a really big couple of days to basically turn off the old main, turn on the new main, connect them onto each other and put the line into service.
“There’s a lot of planning taking place to try to avoid anything going wrong, because it’s something we can’t get wrong – it’s gotta go right.”
Why the need?
Council civil construction manager Graeme McKenzie said in June the current 50-year-old main was close to the ground surface and needed to be relocated to accommodate future proposed road upgrades.
“Council was advised to replace and relocate the main prior to road and roundabout construction, to avoid possible issues which may arise due to vibration from road construction and future increased traffic impacts,” he said.
Mr McGufficke said the new pipework “should last close to 100 years”.
“It depends a lot on what happens in terms of growth over the next 40 to 50 years,” he said.
“We’d sort of expect what we’re putting in at the moment to remain in service for around 50 years, but in theory it can last a lot longer than that.”