UPDATE 1-Canada regulator approves final permits for Trans Mountain pipeline expansion

(Recasts and adds details on final permits and expansion project in paragraphs 1-6)

By Nia Williams and Anushree Ashish Mukherjee

April 30 (Reuters) - The Canada Energy Regulator (CER) on Tuesday approved the final permits for the Trans Mountain oil pipeline expansion, clearing the way for the project to start operating after years of delays and massive cost overruns.

The C$34 billion ($24.69 billion) pipeline expansion, bought by the Canadian government in 2018 to ensure it went ahead, will nearly triple the flow of crude from Alberta to the Pacific coast to 890,000 barrels per day (bpd).

Trans Mountain said this month the pipeline would start operating on May 1, but some shippers including Canadian Natural Resources Ltd, were skeptical it would receive all necessary permits from the CER in time.

The pipeline is now authorized to carry crude from Trans Mountain's Edmonton Terminal in Alberta to its Westridge Marine Terminal in British Columbia, the regulator said in a statement.

"Today marks a significant milestone," CER Chief Executive Tracy Sletto said.

Trans Mountain said last week it would complete line fill on the expanded pipeline in early May and it expected the first tanker to load at Westridge dock in the second half of the month. ($1 = 1.3773 Canadian dollars) (Reporting by Nia Williams in British Columbia and Anushree Mukherjee in Bengaluru; Editing by Chris Reese and Jamie Freed)