If Canada approves Kinder Morgan's Trans Mountain Pipeline expansion, the company's four-year campaign for the project will be far from over. Next up is a battle against hardening opposition among some communities along its planned route.

The CA$6.8 billion (US$5.04 billion) project is a big step toward opening up Asian markets to supply from Canada's massive oil sands. Kinder Morgan plans to build a pipeline parallel to an existing line and nearly triple capacity on the artery to 890,000 barrels per day (Mbbl/d).

Without the expansion, Canadian oil sands producers may find it too costly to ship crude by rail, missing out on billions of dollars of export revenue.

First, the crude must travel from the conservative heart of the Canadian oil industry in Alberta across mountains and grasslands to the liberal west coast. The farther west on the route, the stiffer the resistance to the plan.

The pipeline ends at Burnaby, part of Vancouver's urban sprawl, which already hosts fuel tanks and the marine terminal for the existing pipeline, as well as a refinery. In opposition to further development, thousands of people have taken to the streets vowing to block bulldozers if Trans Mountain construction goes ahead.

The federal government in Ottawa has until Dec. 19 to decide whether to approve it, but the decision could come as soon as this week.

Burnaby Mayor Derek Corrigan said he would join the protests, even if joining could end his political career.

"It's not nice to be a politician who has been 15 years in this office, to be heading into the end of my career with something that would show civil disobedience," Corrigan told Reuters. "I lose sleep about whether or not this is going to turn into being something ugly."

The backlash against a plan to build on sites already dedicated to energy infrastructure shows how entrenched opposition to new energy projects in North America has become.

It also shows how Canada's government is struggling to soothe public concerns despite its pledge to give local communities greater say in the approval process.

Pipeline opponents--British Columbia municipalities, aboriginal groups and environmentalists--are fighting the expansion for reasons ranging from climate change concerns to fears of tanker spills, pipeline leaks or tank farm fires.

Inspiration From The South

They draw inspiration from the fate of Enbridge's stalled Northern Gateway Pipeline, TransCanada's rejected Keystone XL Pipeline and protests against the Dakota Access Pipeline built in the U.S. by Energy Transfer Partners LP.

"Simply because the government will issue a grandiose statement of approval does not mean the project will ever see the light of day," Grand Chief Stewart Phillip of the Union of BC Chiefs, an aboriginal organization, told Reuters in on the eve of a 3,000-strong anti-Trans Mountain rally in Vancouver's center.

In an emailed response to Reuters, the project's media team cited Kinder Morgan's strong safety record in the area, but said it had not expected consensus on the project given a wide range of interests and opinions. The media team noted that the Canadian energy regulator had approved the new pipeline with 157 "rigorous, but achievable" conditions that address environmental and safety concerns that Kinder Morgan is committed to meet.

The pipeline starts from a 140-acre, or 0.57-square kilometer (sq km) tank farm outside of Edmonton, where, like elsewhere in Alberta, new export pipelines enjoy public support as a way to revive the oil province's stuttering economy.

About 800 km, or 497 miles, west in Kamloops, the local businesses and the mayor also back the pipeline. Kamloops, which is in south-central British Columbia, voted Conservative in the 2015 federal election.

"Communities along the interior route have a familiarity with resource-based projects and what they bring," Kinder Morgan Canada President Ian Anderson said at a Kamloops Chamber of Commerce event in November.

But farther west, the sentiment turns against the pipeline. Earlier in November, Liberal lawmaker Ron McKinnon urged Prime Minister Justin Trudeau to reject the expansion because of "overwhelming" opposition on the west coast, where his party did unexpectedly well in the last election.

A recent poll commissioned by one environmental group found nearly one-third of British Columbia's Liberal voters said they would be less likely to support the party if Trans Mountain goes ahead.

From Kamloops, the pipeline climbs over the steep Coquihalla Pass, which separates interior British Columbia from the Fraser Valley and the coast. As the vegetation turns from semi-arid scrublands to temperate rainforest and the route enters the fertile farming region, opposition intensifies.

Grandmothers And Bulldozers

"I know five grandmothers who will go and lie down in front of bulldozers. ... And I will absolutely join them," said Michael Hale, a co-founder of Yarrow Eco Village near Chilliwack, a 20-acre farm under which the existing pipeline runs.

"They may bring in the army, they may throw me in jail, But when I get out I will come back," he said.

The pipeline ends at Burnaby Mountain tank farm near the Westridge marine terminal, which Kinder Morgan aims to expand to load 34 oil tankers one month from five now.

Burnaby's Deputy Fire Chief Chris Bowcock said the planned increase in the number of oil storage tanks on Burnaby Mountain-- from 13 to 27--would raise the risk of a single tank fire spreading across the complex.

Opponents, among them Vancouver Mayor Gregor Robertson, also fear a potential oil spill would cripple the local economy powered by the Port of Vancouver, tourism, and increasingly, the film industry.

Kinder Morgan said it is investing in extra safeguards to mitigate the probability of a tanker spill, but opponents said the risk to the rugged coastline is too great.

"Our first mother is the water," said Reuben George of the Tsleil-Waututh First Nation, whose lands face Westridge Dock. "We will do anything to protect it and we will not let the pipeline go through."

The aboriginal group is planning litigation if the government approves the project.

In June, two conservation groups filed a lawsuit challenging the energy regulator's positive recommendation, saying the oil tankers' route cut across a habitat of an 80-strong pod of killer whales protected under Canada's Species at Risk Act.

If legal action fails, Trans Mountain's opponents said they will resort to civil disobedience. In November in Vancouver, environmental groups gave free training on mass protests, blockades, and de-escalating confrontations with police.

Asked how Kinder Morgan might respond, Anderson told reporters in Kamloops that the company was prepared to talk to all who had a view about the project. "We'll see what unfolds and hopefully we can get through this period in a respectful way."