The Ramsey County Board forwarded to its partners Tuesday an agreement to develop the former Twin Cities Army Ammunition Plant property that includes the sale of the Arden Hills site to developer Alatus for nearly $63 million.

While the framework for the land sale and redevelopment of the 427-acre site has been in place for months, the county, the city of Arden Hills and the developer still need to finalize the cost of the project and who will pay for what.

The deal moved forward by the County Board lays out at least some of those details, including total costs and construction timelines, though much of the contract still needs to be written.

“I think we’re very close,” said Louis Jambois, the county’s lead negotiator on the project and economic development consultant. “We have important details yet to work out. Now is the time to do it.”

The county and developer plan to build a village called Rice Creek Commons essentially from scratch on the former munitions plant site, once the state’s largest Superfund site.

The project, about equal to the size of downtown St. Paul, promises to be the largest redevelopment effort the metro area has seen in years. When complete, it is expected to include 1,460 housing units, support at least 4,000 jobs that pay more than $15 an hour and generate about $8.6 million in property taxes a year.

Under the proposed deal, Alatus would buy the land in five phases, with the first sale going through no later than the end of 2020. Construction on each phase would begin within 11 months after each sale.

In the first phase, which would need to completed by 2025, the developer would build about 170 owner-occupied homes and about 230,000 square feet of commercial and office space.

The contract also requires at least 325 apartments or houses for seniors, a 200-room hotel and about 150 market-rate apartments. That would leave room for about 70,000 square feet of retail, including restaurants, breweries and a movie theater.

The agreement requires that some of the housing be affordable to low-income residents, though not necessarily in the first phase.

The county and the city would be responsible for building roads and connecting the site to utilities. The contract caps the county’s total costs at $51 million, which would be spent building roads. Arden Hills would pay up to $8.2 million to connect the site to water, sewer and other utilities.

The partners will continue fleshing out details of the contract over the coming months before it is brought back to the developer, County Board and City Council for final approval.

The agreement offers a “fair financing plan,” Ramsey County Commissioner Jim McDonough said in a statement. The contract “will hold our developer-partner, Alatus, accountable for meeting our shared goals,” he said.

But the Arden Hills City Council believes the deal is moving too fast. The council this week unanimously urged the County Board to hold off considering the proposal, in order to give the city more time to look it over and negotiate a better deal for the city.

Arden Hills Mayor David Grant, who sits on the project’s Joint Development Authority, said he was given a copy of the proposal only Tuesday. The authority — made up of two County Board members, two Arden Hills City Council members and an Arden Hills resident — will review the contract Sept. 4.

“This is a large transaction,” Grant said. “And over a long weekend, that’s supposed to be enough time to digest it? I don’t think so.”

City officials are taking issue with how much the developer would pay the city for sewer connection fees, and whether it would cover the city’s staff and consultant costs.

“There are just a lot of details that are not in [the proposal] and that haven’t been fully resolved,” Grant said.