The court announced today that it had rejected the application from the Coldwater Indian Band, Tsleil-Waututh Nation and Squamish Nation seeking to appeal the Federal Court of Appeal's decision. It purchased it in 2018 to ensure the expansion. He has promised to reduce Canadian emissions and improve indigenous relations, but faced pressure to help the slumping oil industry critical to the national economy.
Expansion of the 67-year-old pipeline is well under way.
The $12.6-billion project, already under construction, will twin an existing 1,150-kilometre pipeline from near Edmonton to Burnaby, tripling capacity to 890,000 barrels per day.
The pipeline would end at a terminal outside Vancouver, resulting in a seven-fold increase in the number of tankers in the shared waters between Canada and Washington state.
The February Federal Court of Appeal decision found the First Nations wanted the project held to a standard higher than the law requires.
But in February the same court dismissed another challenge by the same groups against the government's June 2019 decision to approve the project a second time after another round of Indigenous consultation.
They were based on concerns from British Columbia Indigenous groups that Ottawa had not meaningfully consulted them.
Alberta Premier Jason Kenney Chris Schwarz Government of Alberta
Kenney added the decision brings the country closer to a prosperous future for all First Nations peoples.
Canadian pipelines have always been congested, but this year, space opened up as producers curtailed production.
The pipeline expansion still faces stiff environmental opposition from British Columbia's provincial government but construction is under way.
Natural Resources Minister Seamus O'Regan welcomed the decision but acknowledged some might be disappointed.
Tsleil-Waututh Chief Leah George-Wilson and Syeta'xtn (Chris Lewis) of the Squamish Nation will be hosting a virtual news conference later Thursday.
"The government approved TMX because it is an important project for Canada", he said in a statement. The hope is that this pipeline will carry more Canadian oil to the Pacific, where it can make its way to Asia and raise the price companies can get for oil.
Most Canadian crude moves to US refineries and expanding Trans Mountain may allow more to go to Asia.