The Canada Energy Regulator (CER) has approved the request for route deviation of the multi-billion-dollar Trans Mountain oil pipeline expansion project.

The CER’s decision comes after a three-day hearing held in Calgary last week.

The expansion project is essentially a twinning of the original Trans Mountain Pipeline, which was built in 1953 and remains operational to this day.

Last month, state-backed Trans Mountain Corp (TMC), which is building the new pipeline, applied to alter the route for a 1.3km section of the pipeline in Kamloops, British Columbia.

TMC said that the new path avoids micro-tunnelling construction, which is not viable technically and economically.

It added that if micro-tunnelling is required, the pipeline segment in question might not be finished until December 2024, according to Reuters.

Originally, the pipeline was expected to commence operations in January 2024.

The company proposed to install the pipeline via a different route close by using horizontal directional drilling and a traditional open trench technique.

However, the plan was opposed by the Stk’emlupsemc te Secwepemc Nation (SSN) First Nation, an indigenous group.

According to SSN, the area where the pipeline would pass “holds profound spiritual and cultural significance to the nation and peoples”.

The regulator did not provide a reason for its decision, which is expected to be released in the coming weeks.

The new 1,150km pipeline between Strathcona County, Alberta, and Burnaby, British Columbia, will carry an additional 590,000 barrels of oil sands petroleum to Canada’s Pacific Coast daily.

Once fully operational, the pipeline is expected to enhance Canada’s capacity to export crude oil to the west coast of the US and Asia.

The project, which has been plagued by years of delays, is expected to cost C$30.9bn ($22.97bn), over four times its initial budget.

Last month, media reports emerged that the Canadian Government could sell its stake in the Trans Mountain oil pipeline to indigenous groups.