The federally owned Trans Mountain Corp. said Wednesday it has issued "notice to proceed" directives to construction contractors, mobilizing the workforce it needs to expand the pipeline.

"I am pleased to announce another significant milestone for the Trans Mountain expansion project," the corporation's CEO, Ian Anderson, said in release.

"With the first wave of regulatory approvals complete, we are confident that we have a path forward by which the expansion project construction can commence."

Contractors are expected to begin mobilizing equipment and crews in "select areas" in August and September.

"Construction work will soon begin in communities along the route, including along the right-of-way in Alberta between Edmonton and Edson, and in the Greater Edmonton area," the corporation said in Wednesday's release.

Work in British Columbia

"This includes an immediate return to work at Burnaby Terminal and on land at Westridge Marine Terminal. Specific start dates in the remaining construction areas are subject to final regulatory approvals and permits."

The corporation expects to receive those additional approvals and permits "over the coming months" and, provided that happens, says the expanded pipeline will be in service by mid-2022.

Trans Mountain expects 4,200 workers will be employed along the corridor by late 2019 and says it "remains committed to prioritizing and maximizing Indigenous, local and regional hiring to the greatest extent possible."

"Clearly this project has been subjected to numerous delays and setbacks over the past several years," Anderson said.

"With today's announcement on the commencement of construction, I firmly believe that we are finally able to start delivering the significant national and regional benefits we have always committed to."

Conservatives slam pre-election timing

Natural Resources Minister Amarjeet Sohi, who represents the riding of Edmonton Mill Woods, held a news conference Wednesday in Sherwood Park, Alta., where he praised the Crown corporation's announcement.

Sohi called it a "greenlight to proceed" with the physical work of the Trans Mountain expansion, after the Liberal cabinet approved the project and the National Energy Board issued a certificate in June.

"We're very happy that people will be actually in the field, digging the ground and installing the pipe," Sohi said.

"It's a very exciting time for Alberta. It's a very exciting time for Canada. This is a project that is in the national interest."

Conservatives, meanwhile, criticized the timing of the announcement — given that a federal election is set for Oct. 21 — and also took aim at the Liberal government's broader policy on pipelines.

"Weeks before the federal election, the natural resources minister has finally confirmed some timelines for the construction of the Trans Mountain pipeline," Edmonton Riverbend MP Matt Jeneroux said in an emailed statement.

"This is after four years in which the minister and his government actively worked to destroy our energy sector by cancelling projects like Northern Gateway and Energy East and passing legislation like the no-more-pipelines Bill C-69."

TransCanada (now TC Energy) scrapped the Energy East pipeline project in 2017 over regulatory pressure.

Alberta Premier Jason Kenney issued a statement Wednesday that criticized the federal government.

"With the passage of the 'No More Pipelines' Bill C-69 and the Alberta tanker ban, Bill C-48, TMX will be the only new coastal pipeline for the foreseeable future," the premier said.

"This is unacceptable."

Gary Mar, a longtime cabinet minister in Alberta's past Progressive Conservative governments and current CEO of the Petroleum Services Association of Canada, said Wednesday's announcement amounts to little more than political posturing.

"I've been in politics long enough to know that there are many times when things are done to show projection of effort," he said. "And this is a projection of effort."

More resistance anticipated

Mar added that the mobilization of pipeline workers is "good news," in his view, but many in Alberta's oilpatch aren't celebrating just yet.

"Here's the big condition: it remains to be seen whether there will be civil disobedience or more attempts through the court and litigation process to delay this one more time," Mar said.

"So until the pipeline is actually complete — not just started, but complete — I'm not going to be popping a champagne cork."

Pipeline opponents have vowed to continue fighting the project, through legal means and otherwise, with some predicting last year that more people will be arrested opposing Trans Mountain than were arrested fighting to stop logging in Clayoquot Sound on the west coast of Vancouver Island more than two decades ago.

Those demonstrations marked the largest civil disobedience protest in Canadian history.

Over the past year, numerous demonstrations have been held in Alberta in support of Trans Mountain — and pipeline expansion in general — that have regularly drawn hundreds, if not thousands of people.

On Tuesday, the Conference Board of Canada forecast that Alberta's economy will shrink by 0.8 per cent this year, which it described as a "mild recession" that is largely due to uncertainty surrounding pipeline capacity.