A construction company whose tunnel boring machine got stuck underground for more than a year while excavating new sewers near Old Mill is suing the city for money it says it’s still owed for its work on the multimillion-dollar rescue of its digging device.
Clearway Construction Inc. says the city still owes it more than $4 million for the rescue of its digging machine, which became ensnared in underground steel cables while it was tunnelling.
The steel cables, known as tie-backs, are to stabilize walls and prevent the weight of soil and water from collapsing or moving the structure being built. In this case, the steel wires were left underground from nearby condo foundation work.
The city’s director of engineering and construction services told the Star in 2023 the developer had the municipality’s permission to bury the tie-backs used in its early construction stages.
According to court documents filed by Clearway, the city did not tell it that the tie-backs existed, nor were they on drawings the city’s designers prepared for the sewer replacement project.
“The records were either missed by the city entirely or not disclosed to the consultants that designed the Old Mill Project for the city,” according to the statement of claim filed in October, adding that the damage and the project’s delay were consequences the city should have predicted.
The city had not filed a statement of defence as of Thursday. A spokesperson said the city cannot comment further given the lawsuit is ongoing.
“These claims are subject to litigation,” the spokesperson told the Star in a written statement on Tuesday. “The city is reviewing how it deals with underground infrastructure in its roads, including tie-backs.”
Clearway did not respond in time for publication.
City hall hired Clearway in July 2021 to upgrade the storm and sewer system on Old Mill Drive near Bloor Street West to help flood-proof homes in the area. The work began that September.
The boring machine entangled in a steel tiebacks near Old Mill station during sewer construction.
Courtesy City of TorontoThe digging machine began boring a 282-metre tunnel from Old Mill Drive and Riverside Drive in spring 2022. But, just seven metres short of the end point near Bloor, the machine got snared in the tie-backs.
The $3-million boring machine was trapped until October 2023 when Clearway and one of its subcontractors carried out a time-consuming and complicated rescue the city estimated could cost it as much as $25 million, though it has yet to report its final number.
During the rescue, wet and unstable soil triggered dangerous sinkholes above ground, and the work was paused while Clearway called in a ground stabilization firm.
According to the court documents, the city told Clearway last year it won’t pay the remaining millions because the stabilization company accidentally pierced a sewer pipe during its efforts to inject grout into the area to stabilize the ground, and as a result grout got into sewer and storm pipes.
“All of which Clearway states are invalid, improper, unsubstantiated and/or exaggerated,” according to the claim.
Tamer El-Diraby, a civil engineer and professor at the University of pc28who was not involved with the construction project nor the lawsuit, said that generally, large cities don’t always track and upgrade their maps very well for such underground infrastructure.
“It’s a big dilemma. This is why we have locate services,” he said, referring to businesses usually hired during construction to identify where various utility lines are located.
It’s unclear what the terms of the Clearway contract are as the city does not automatically release the full details of contracts for privacy reasons. But in general, El-Diraby said, construction contracts place the onus with companies to make sure it locates utilities under ground.
Yet this case is unique, he added, because “you have a gas line or water line everywhere in the city, but only a few locations have tie-backs.”
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