Construction crews may soon appear on a large swath of suburban land that's sat empty for more than 40 years. The Ramsey County Board has given the green light to Rice Creek Commons — a mix of homes and businesses planned for the site of the former Twin Cities Army Ammunition Plant.

The factory began churning out .30- and .50-caliber ammunition during World War II, and then closed for good in 1976. In the ensuing decades, soil and groundwater pollution made the land unsafe to reuse. In the 1980s, the site was added to the EPA's Superfund program.

Ramsey County entered the picture in 2013 when it bought 427 acres of the site beside Interstate 35W and — with the Army's help — began cleaning it up.

"We expect to delist that site from soil contamination. It is basically ready to go," said Louis Jambois, an economic development consultant who is Ramsey County's lead negotiator on the project. He expects construction crews could start grading the land as soon as next year.

Meeting in closed session Tuesday, the Ramsey County Board gave the go-ahead to sell the site to the developer Alatus, LLC for nearly $63 million. The proposal calls for the company to acquire the property in five phases between 2020 and 2034.

The master plan includes three residential neighborhoods, plus parks, retail and office space to be called Rice Creek Commons.

Arden Hills Mayor David Grant welcomes apartments and condos in a city of mostly single-family homes. They'll allow people who can no longer manage the upkeep to remain in the community as they get older.

But Grant worries that county leaders are moving too quickly. He says the board is only giving city leaders a few days to review the latest draft of the master development agreement ahead of a key vote next week.

"They gave us no time to review, and they want to move on it on Tuesday, Sept. 4. I haven't had a chance to read it," Grant said.

Grant said the city doesn't know yet who will pay for sewer lines. A spokesperson from the Metropolitan Council said Wednesday that Arden Hills has access to sewer credits currently worth around $11.4 million for use on the project. Grant also hopes to recover the city's own costs for planning and consultants.

Ramsey County Board Chair Jim McDonough said the plan fits within the original principles the city and county agreed upon when the project started, and that Arden Hills officials and their consultants have had two months to comb through the development agreement.

"There's been a number of conversations between all the partners at different levels about where we're at in that master development agreement," McDonough said. "And the county and Alatus certainly feel that it's time to move this project forward."

The plan goes next to the city-county joint development authority set up to oversee the project. The panel includes Mayor Grant and an Arden Hills council member, and will decide next Tuesday just how quickly the Rice Creek Commons project moves forward.

Correction (Aug. 29, 2018): A previous version incorrectly stated Metropolitan Council actions regarding sewer fees. The above story has been corrected.