The Executive Council approved a contentious plan Wednesday to expand the Mount Sunapee ski resort in a 3-1 vote, ending the latest chapter in a long effort by the resort, but potentially opening the door to another – in court.

Opponents of the plan, including the Sierra Club, said they were considering legal action after the council voted in favor of it. Republican Councilor Chris Sununu recused himself because he runs Waterville Valley.

“We will use every resource available,” said Catherine Corkery, a field organizer for the club’s state chapter.

Under the plan, the resort will add four new runs and a chairlift. In return, it has agreed to transfer ownership back to the state before construction begins, ensure year-round hiking and pay for research of sensitive habitat.

Opponents argue that, despite the concessions, the project will still degrade public land, price out low-income families and open the door for slopeside condominiums.

Democratic Councilor Colin Van Ostern, who is facing Sununu in a race for governor, was the lone opponent. Speaking before the vote, he said the plan had improved after two years of review by the Department of Resources and Economic Development, but still skewed the balance of the mountain too far toward commercial enterprise.

“I welcome the growth of more visitors to Mount Sunapee,” Van Ostern said. “I believe there’s a way to achieve that, that brings both more skiing and more hiking, and doing it in a way that isn’t creating effectively exclusive private access to some public trails, which I think might be inevitable under the way the plan would actually be implemented.”

Republican Councilor Joe Kenney supported the project but said there were still issues to address through the local permitting process, including the placement of two of the new runs.

“While today we’re voting on the lease, ultimately there’s going to be a lot more citizen input in the future of Mount Sunapee,” Kenney said, adding that the vote was one of the hardest he’s made on the council.

The resort has been trying to expand for nearly two decades, and supporters, many of whom turned out Wednesday, believe it will create jobs and stimulate the local economy.

Critics also turned out in strong numbers to show their opposition. Some were vocal.

“You break our hearts,” one opponent told Jeff Rose, commissioner of DRED, as she streamed out of the council chambers.

“This isn’t over,” another said.

Corkery said her group and another, Friends of Mount Sunapee, were looking into legal actions. She cited no specific claim, but said there are “discrepancies” between the existing lease and the proposed agreement.

Joe Foster, the state’s attorney general, told the council before the vote the contract appeared legally sound.

The resort’s vice president and general manager, Jay Gamble, appeared reserved after the vote, telling reporters he was “thankful” for the council’s support. He said the business hopes for at least a 20 percent growth in revenue from the expansion, some of which will go to the state and local communities.

Gamble said the permitting process will likely take another three to four years to complete.

​(Jeremy Blackman can be reached at 369-3319, jblackman@cmonitor.com or on Twitter @JBlackmanCM.)