A U.S. federal appeals court ordered work to stop at a major oil project on Alaska’s North Slope, siding with conservation and Indigenous groups. The decision Saturday by the 9th U.S. Circuit Court of Appeals will stop on-the-ground work for the winter at the Willow project operated by ConocoPhillips Co., according to Associated Press.

Ice roads support wintertime work at projects on Alaska’s North Slope, but they melt in the spring and that drastically reduces what can be done for all but a handful of months. The Willow project in the National Petroleum Reserve-Alaska was expected to provide jobs for about 120 people this year.

ConocoPhillips is expected to decide later this year if it will pay billions of dollars to develop Willow for oil production, with the first oil not expected to flow until the mid-2020s.