DULUTH — The Duluth Seaway Port Authority has been awarded a $10.5 million federal grant to help improve and expand a busy terminal that last year handled a record amount of wind turbine parts arriving from overseas.

With a total project cost of about $20.3 million, the port plans to add a 56,000-square-foot warehouse, reconstruct roughly 1,700 feet of dock wall and fortify about 7 acres of cargo space, among other upgrades.

The grant is among the largest the port has ever received and adds to more than $25 million in investments at the Clure Public Marine terminal over the past four years.

"This grant supports projects that improve and broaden the infrastructure of the Clure Public Marine Terminal and the value it provides," Deb DeLuca, executive director of the port authority, said in a statement.

The federal money, from the Port Infrastructure Development Program, will restore and enhance the only combination ship, rail and truck terminal in Minnesota north of the Twin Cities, according to Rep. Pete Stauber, who announced the grant along with Sens. Amy Klobuchar and Tina Smith.

In a letter to Secretary of Transportation Elaine Chao requesting the grant last year, Stauber emphasized significant cost savings manufacturers get from using the port over other freight options.

The 120-acre Clure Public Marine Terminal first opened in 1959 and today is home to three general cargo berths and 430,000 square feet of warehouse space "in high demand by regional businesses," the port says. Upgrades in recent years include the rehabilitation of a 28-acre dock, adding two new berths, installing on-dock rail and last year's $3.2 million expansion of the intermodal terminal.

Duluth Cargo Connect, a public-private partnership between the port authority and Lake Superior Warehousing, operates the publicly owned terminal.