ConocoPhillips can begin construction immediately on the Willow project in the western Arctic, a federal judge ruled Monday.

U.S. District Court Judge Sharon Gleason denied requests for an injunction that would have stopped the company from working in the final weeks of the winter construction season, which will likely end in late April, when the tundra becomes too soft for heavy equipment to travel on.

Environmental groups and local residents who oppose the project filed two lawsuits last month, claiming the decision to allow ConocoPhillips to develop its leases in the National Petroleum Reserve was made contrary to environmental laws.

Those cases are still pending. But the judge declined to stop work on Willow in the meantime, saying the plaintiffs did not convince her that the company’s winter construction plans would cause serious and irreparable harm.

Her decision frees ConocoPhillips to embark on its plan to build ice and gravel roads, open a gravel mining site and begin hauling and dumping gravel in the National Petroleum Reserve-Alaska. Noise and vibration from blasting at the mine site won’t cause permanent harm, the judge wrote.

She acknowledged that the mayor and some residents of Nuiqsut — the closest village — have concerns about Willow, but Gleason said she gave “considerable weight” to the views of the North Slope Borough, the regional Native corporation and the village corporation for Nuiqsut, all of whom support the project and the winter construction activities.

The Wilderness Society, one of the groups that is suing, issued a statement vowing to continue to fight the project.