City of Toronto spending $9M to rescue boring machine trapped underground in west end

The City of Toronto has launched a delicaterescue operation in the west end that will cost taxpayers $9 million to free aboring machine trapped underground after nearby sewer work went awry last year.

Dozens of workers have been busy for months on Old Mill Drive as they work to excavate the $3-million micro-tunnelling machine, which gottrapped near Bloor Street West sometime last spring. A report coming to city councillorsFriday says the situation represented a "significant health and safety hazard to the public."

But for people who live and work along the normally quiet street, the project has been a constant headache, says Paul Aiello, who owns a home on Old Mill Drive. The noise, mud and daily flood of construction vehicles is wearing on neighbours, he says.

"There's a lot of inconvenience because we can't get through the streets and there's a lack of communication in terms of what the problem is," he told CBC Torontoas the piercing noise of a construction vehicle's back-up beeper cuthim off.

Standingback and watchingthe vehicleswivelinto position as workers move around it, Aiellosaid: "There's a lot of construction noise, a lot of dirt even the park is kind of out of commission."

'The road started to collapse'

Greg Tershakowec's dental practice looks out onto the roadway, which is nowfenced offto secure the construction zone. He saysthe disruption has made it hard for some patients to get to his office.

"It is frustrating for me but you have to live with it; you're dealing with the noise all the time," he said.

Tershakowec saysit became apparent last spring that something was seriously wrong.

"What happened was that initially the road started to collapse," he said. "And that was the first sign of problems."

The work to dig a new storm sewer on Old Mill Drive began in March 2022. The project was designed to address chronic basement flooding in the area. City staff opted to use a remote controlled micro-tunnelling boring machine,which is 1.5 metres wide and five metres longto create the new sewer tunnel.

The plan was for the machine to be placed 18 metres below ground and have it travel 282 metres to a pre-constructed exit shaft onBloor Street West. Workersneeded toplace itdeep underground to avoid coming into contact with the nearby Bloor-Danforth subway line.

But with just seven metres left to go on its route, the machine hit 14 underground steel tiebacks, which had been part ofthe construction of a nearby condo building. It became ensnared in them, and is now twisted and turned off course.

The city says it didn't know the tiebacks were in place when it initially plottedthe route. But a subsequent record search after the machine had hit the tiebacks found that the developer gotpermission from the city to leave themunderground after that project was completed.

Mika Raisanen, a director in the city's engineering and construction services department, saysworkers hand-dug to the machine, but as work progressed to extract it, damp soil and water have complicated the operation. Now trucks are moving in and out of the area daily to dry the underground soil immediately around the machine.

That will allow workers topulled the machine apart and remove itin pieces.

'Back to square one'

Raisanen said city staff contemplated a number of options, including leaving the expensive machine in the ground, but that would have meant restarting the project and boring a new tunnel.

"We had to stop the operations and kind of shore up our rescue efforts," he said. "And we did have a couple of sinkholes that came to light and we had to fill them in."

Ultimately, the city began work last spring to extract the machine and finish the last seven metres of the sewer tunnel by hand.

"We look at cost, we look at risk, what can happen, what's feasible," Raisanensaid. "And also, the end product if we left it in the ground, where it was. That means we're back to square one."

He saysdepending on the weather over the next few weeks, and how much moisture workers are dealing with on the site, they hope to rescue the machine by early April. They'll complete the sewer tunnel by hand.

"This exact scenario, I would say, it's not something that we do every day," Raisanen said, asking for patience from residents who he acknowledgeshave had to livewith the disruption.

"We're almost there and completing the project," he said.

"In the end, when the work is done, it'll reduce flooding. That's the intent."

Councillors look to recover costs

During a general government committee meeting at City Hall on Friday, city councillors discussed the stranded machine and costs to complete the project.

Staff told councillors that a consultant was hired to conduct the initial tunnel design work.

The city says that after the machine is rescued next month, it plans to have the sewer work done by June. The street will be re-opened by August.

Councillors on the committee passed a motion asking staff to review the circumstances of the incident and to report back on April 20, setting out options available to the city to recover its costs.