As usual, the court did not give reasons for its decision.
First Nations leaders were planning a press conference later Thursday to respond to the court decision.
The Trans Mountain project was first approved in 2016, but stopped by the Federal Court of Appeal two years later after First Nations and environmental groups successfully argued that the approval process was flawed.
Ottawa approved the project a second time in June 2019 after having undergone additional consultations with affected communities, but the bands still believed that the government was not fulfilling its obligation to consult and again appealed to decision.
The Federal Court of Appeal ruled in February that the approval would be maintained, saying the government had made a real effort to hear and respond to the concerns raised. But the First Nations disagreed and asked the Supreme Court to hear the case.
The bands continue to have concerns about the impact the pipeline may have on drinking water as well as lingering concerns about the effect on marine life – particularly the highly threatened southern resident killer whales – off the coast. British Columbia. coast.
Thursday’s decision appears to be the end of the road for legal arguments to stop construction of the pipeline.
In January, the Supreme Court said that the B.C. government did not have the power to try to regulate what could flow through the pipeline, which, as an inter-provincial project, falls under federal jurisdiction.
The court also refused in March to hear a challenge from environmental groups who were denied the right to appeal the second approval.
The expanded pipeline will almost triple the amount of diluted bitumen flowing between the Alberta oil sands and a seaport in Burnaby, British Columbia.
Originally proposed by Kinder Morgan Canada to match the existing pipeline that carries both refined products and diluted bitumen, the pipeline has become a political symbol of the struggle to find out if Canada can continue to extract and sell fossil fuels and to fight climate change.
In 2019, shareholders of the company were cautious about the continued multi-billion dollar expansion, fearing that legal challenges from Indigenous communities, environmental groups and British Columbia. the government would delay construction for too long.
The federal Liberal government failed to convince society that it could overcome legal hurdles and, in May 2018, bought the existing pipeline for $ 4.4 billion with a promise to expand and everything resell to the private sector.
This decision was hit hard a few months later when the Federal Court of Appeal canceled the approval, halting construction. Construction resumed last summer after the second approval and has continued despite new legal challenges.
Prime Minister Justin Trudeau has always tried to sell the project as his government’s compromise between the economy and the environment, arguing that Canada cannot pay for the transition to a cleaner, greener future if it gets the best out of it. natural resources, which remain in demand around the world.
Most of the oil produced in Alberta is sold at a discount because Canada is so dependent on the United States as its customer. The hope is that this pipeline will carry more Canadian oil to the Pacific, where it can go to Asia, thereby increasing the price that companies can get for oil.