An extra C$20 million ($15 million) has been added to construction costs of the Trans Mountain Pipeline expansion for a detour around a southern British Columbia (BC) native tribe, according to evidence before the Canada Energy Regulator (CER).

The oil pipeline’s route change raises the expense of steering the project past the Coldwater Indian Band to C$70 million ($52.5 million) from C$50 million ($37.5 million), Trans Mountain disclosed in a reply to a CER information request.

The extra bill is a relatively small addition to the total cost of expanding Trans Mountain as an export route for Canada’s top natural gas user, Alberta thermal oilsands production.

The added expense of the Coldwater detour is just 1.6% of the C$12.6 billion ($9.4 billion) current estimate for...