Weather, topography challenges for Vaughan pipeline

Dailycommercialnews.com
June 23, 2017
By Dan O’reilly

Winding its way north and then east, a 12-kilometre-long, 42-inch-diameter TransCanada Corporation natural gas pipeline under construction in the city of Vaughan is intended to meet the needs of the energy industry’s customers in Ontario and Eastern Canada.

But planning, designing and then building the Vaughan Mainline Expansion comes with a host of challenges, notably traversing both the Humber and East Humber rivers and dealing with incredibly rainy weather. The expanded line's in-service date is this November.

Edmonton area-based Banister Pipelines is the general contractor building the line from an existing valve site at Huntington Road and Major Mackenzie Drive to an existing pipeline at Kipling Avenue and Kirby Road. The pipeline supplier is The Welspun Group, a firm based in India.

After being shipped to Vancouver, the pipe was transported by train to the nearby CN intermodal rail yard in Concord, Ont. where its pieces are moved on an as needed basis. The various pieces are welded together on site, says TransCanada project manager Nelson Jalojot.

"We wouldn't have built it if there wasn't the demand (for natural gas)," says Jalojot, in tracing the project's history.

That demand was confirmed in late 2014 through what is known as "new capacity open season." This is a process in which TransCanada and other energy firms solicit commitments and then sign long-term agreements with 'shippers' or customers for additional capacity.

What followed was a major planning and design exercise including pinpointing the route, signing agreements with the affected property owners, conducting geotechnical, environmental and other studies and securing a pipe manufacturer.

Various factors, such as the coating of the pipeline, also had to be considered, he says.

In August 2016, the National Energy Board (NEB) approved the project, with construction starting in November.

"Once the planning has been completed and the NEB approval is in place, it can be a relatively quick construction start," says Jalojot, when asked about the short turnaround.

Normally, pipelines are installed right from the starting point to the end point in one continuous operation he compares to a conveyor line. That's not the case with the Vaughan Mainline Expansion which requires a number of different crews and construction techniques.

A majority of the pipeline is being installed using conventional trenching techniques, with boring used underneath roads to eliminate closing or partially closing those roads, he says.

In the case of crossing, or more precisely, going underneath each branch of the Humber River, horizontal directional drilling (HDD) was utilized to minimize the environmental footprint including the impact on fish habitat, the riverbank and adjacent wetlands. There were a number of factors that had to be considered with this construction method, including existing soil conditions, noise and the length of completion time compared to conventional trenching. Banister Pipelines recently completed the HDD underneath the East Humber, a procedure that took 60 days, he says.

It is also being used to cross nearby Nashville Road and several other environmental features and was to be deployed at the main Humber River site.

But long periods of rain that blanketed southern Ontario for most of the spring created wet soil conditions which ruled out using HDD, says TransCanada senior communications specialist Jennifer Link.

Instead, TransCanada has filed a variance application with the NEB for direct pipe installation (DPI). Once approved, the installation will take four to six weeks to complete, including equipment set-up time, with an estimated drilling of between 12 to 15 days.

Some geological work was underway in early June in preparation for the DPI crossing, says Link, noting that variance applications are not uncommon in the energy industry.

In advance of that application TransCanada officials met with the Toronto Region Conservation Authority "to walk us through the DPI methodology," says authority planner Suzanne Bevan.

Unless there are some major geotechnical issues, the authority prefers trenchless methods as opposed to open cut construction at watercourses as it is less invasive, she says.

There was extensive consultation between the authority and TransCanada over routes and design in an almost three-year process leading up to the NEB application, says Bevan.