Over 70 people were arrested during the bitter protests in November and December that aimed to stop the company's pipeline exploration work on the mountain.
In December, Trans Mountain said, it approached the five defendants and offered to drop the suit on a without-costs basis. Two of the defendants agreed, with two others demanding an assurance first that the company would not revisit the action in the future, and one — Allan Dutton — refusing to negotiate on principle.
In a statement issued Friday, Trans Mountain — the company behind the Kinder Morgan pipeline proposal — said that it had filed a unilateral discontinuance on the three defendants who had not settled, and would accept any subsequent costs incurred.
The company states it is willing to pay any such costs "in order to demonstrate, without any doubt, that it has no intention of pursuing civil action in this case."
One of the original five defendants, Simon Fraser University English professor Stephen Collis, told CBC News he was relieved the case had now been dropped completely.
He said it was evidence that the protests had worked, and that the pressure on Kinder Morgan had forced it to try to "save face" by dropping the lawsuit and changing its media campaign.
"It's a PR move,' he told CBC News. "I think the whole situation has forced them to start doing some really drastic things on the PR front because they took a beating."
In January, the B.C. Supreme Court rejected a bid from Dutton, a retired professor, to have the lawsuit thrown out.
He said that even though the court disagreed, Kinder Morgan only brought the original suit in an attempt to silence protesters.
"I'm mad, and I am madder now than I was before, and I am more committed to fighting back against what Kinder Morgan has done to me and what it has done to other people."
He had refused to settle with Trans Mountain as a matter of principle, he said, despite the possibility that he could have incurred court costs himself.