Collapsing oil prices have delayed at least two North American liquefied natural gas export projects, but they haven't stopped Alaska's massive LNG venture in part because of its size, projected timelines and a partnership involving some of the world's largest companies, officials said. "Our mission hasn't changed, and to my knowledge none of the investing companies are looking to change that at this time either," said Steve Butt, senior manager for Alaska LNG and an Exxon employee.