CBC News.  For the past 25 years, oil and gas exploration in the Beaufort Sea has kept Inuvik on an economic roller coaster. In March 2011, the National Energy Board granted final approval for the Mackenzie Valley natural gas pipeline after the federal cabinet signed off on the long-delayed $16.2-billion project. Low natural gas prices have kept the project on the drawing board since then, although in August, Imperial Oil asked the National Energy Board to extend the sunset clause on regulatory approval through 2022 in the hopes that gas prices will improve.