"The government considers that these projects are likely to cause unacceptable environmental effects within federal jurisdiction and are not aligned with Canada's domestic and international climate change commitments," he said.
In a statement, Wilkinson said thermal coal - primarily used for generating electricity - was the single largest contributor to climate change.
Canada produced 57 million tonnes of coal in 2019, just 1% of the overall global total. Canadian output in 2019 comprised 47% thermal coal and 53% metallurgical coal, which is used for steel manufacturing, according to official data.
"The continued mining and use of thermal coal for energy production in the world runs counter to what is needed to effectively combat climate change," Wilkinson said. In 2018, Ottawa introduced regulations to phase-out conventional coal-fired electricity across Canada by 2030.
The new policy would apply to privately-held firm Coalspur's plans to expand an existing thermal coal mine in the western province of Alberta, he said.
(Reporting by David Ljunggren; Editing by Kirsten Donovan)
