(Calgary) The Canada Energy Regulator on Friday released the reasons for its decision last month to authorize the deviation of the Trans Mountain Corporation pipeline against the wishes of a British Columbia First Nation .

In its written reasons released Friday, the regulator explained that it shared Trans Mountain’s position that being forced to stick to a previously agreed upon route and construction method, despite difficulties encountered in tunneling through rock in this area, would result in unacceptable delays and increased costs.

Following an oral presentation in September, the regulator ruled in favor of Trans Mountain’s request to slightly reroute a 1.3 kilometer pipeline section to be built in the Jacko Lake area near Kamloops, British Columbia.

The First Nation had argued that the area had “deep spiritual and cultural significance” to its people and that it had only consented to the construction of the pipeline knowing that it would minimize surface disturbance by implementing methods of specific trenchless construction.

But the regulator said it accepted Trans Mountain’s argument that being forced to continue attempting to tunnel through the area originally proposed could delay completion of the pipeline by up to 10 months, which would result in a loss of operating revenue of approximately 2 billion.