Preston — The Preston Redevelopment Agency and the Mohegan Tribe have asked for a 90-day extension, to Feb. 19, of the negotiation period that is expected to conclude with the sale of the former Norwich Hospital property in Preston to the tribe for a major development totaling some $600 million.

The Board of Selectmen voted unanimously Thursday to agree to the extension after hearing from PRA Chairman Sean Nugent that this would be the only extension needed to complete the negotiations. Nugent said the parties expect to have a Property Disposition and Development Agreement, or PDDA, completed by the new deadline.

Tribal and town officials announced on May 12 that the tribe was interested in buying the entire 393-acre former Norwich Hospital property in Preston for a major nongaming development described at the time as a “high-quality” mixed use development. Tribal Chairman Kevin Brown later said the project could include business development, outdoor recreation, including a “glamour camping” facility, a synthetic ski slope and an adventure park.

The Memorandum of Understanding reached between the town and the tribe on May 19 called for a 180-day negotiation period that would end Nov. 19 without the extension.

Nugent told the selectmen that much progress has been made in recent weeks during closed-door negotiation sessions, but the two parties have exchanged questions and asked for more information that will require more time to complete.

“We've come to a joint conclusion that it's not going to happen by Nov. 19,” Nugent said. “But it is going to happen.”

After the selectmen meeting, Nugent said he could not comment on specifics of the issues in the negotiations that will need more time to iron out.

The time schedule remains tight even with the extension, town officials admitted Thursday, because all approvals are expected to be in place by the new Feb. 19 deadline — including a vote by the State Bond Commission for the pledged $10 million state contribution to finish the environmental cleanup of the property, and town meeting approval in Preston for the PDDA.

First Selectman Robert Congdon said the only approval not within the town's and tribe's control is the State Bond Commission schedule.

Prior to a town meeting seeking residents' approval of the agreement, officials also expect to hold public information meetings on the proposal, Nugent said.

“I'm kind of hoping that you're pretty far along the road,” Preston Selectman Michael Sinko said, “because this is a bad time of year to get things done — the holidays.”

Congdon, an ex officio member of the PRA, said the past two weeks have been “very, very busy” with meetings involving the PRA, Mohegan tribal officials and state officials related to the promised state bond.

Asked if the negotiations are “two-thirds done,” Nugent said some aspects are farther along than that.

After the Board of Selectmen approved the extension, Nugent handed out a news release with statements from tribal officials regarding the extension.

“Both parties have agreed that an additional 90 days is needed to allow (Mohegan Tribal Gaming Authority) to complete its due diligence of the property and for both parties to complete the PDDA,” the release said.

The tribal gaming authority already has agreed to the extension, it said.

“While we are eager to showcase our vision to the townspeople of Preston, collectively, we believe a minor delay to ensure we get things set correctly is worth it in the long run,” Brown, chairman of the Mohegan Tribal Council, said in the release.

c.bessette@theday.com