BROOKINGS, S.D. -- Two Sioux Falls, S.D., men who have been business partners and friends for years are donating $12.5 million to a proposed football stadium at South Dakota State.

Retired banker and philanthropist T. Denny Sanford is donating $10 million, and banker and former Jackrabbits defensive tackle Dana Dykhouse $2.5 million. The men announced their pledges this past weekend during halftime of the SDSU football game, with university president David Chicoine calling it "a milestone occasion."

The 18,000-seat facility will cost up to $65 million to build and will be named the Dana J. Dykhouse Stadium. Officials expect to submit a plan to the state Board of Regents this month. The project is to be funded largely by bonds that will be paid off during several decades through stadium revenue. It also will need the approval of the state Legislature.

The current Coughlin-Alumni Stadium on the SDSU campus in Brookings is 51 years old and lacks modern amenities and adequate seating. Officials hope to open the new one in 2016.

"Because of this new facility, you're going to be able to recruit the best athletes in the country," Sanford said.

It's not the first time Sanford and Dykhouse have worked with the university. In 2007, they donated $6 million to create the Dykhouse Student-Athlete Center, the headquarters of the Jackrabbits football program, in the north end of the current stadium. This summer, SDSU broke ground on a $32 million, 161,500-square-foot indoor practice and track facility that will be connected to the Dykhouse Center. It will be called the Sanford-Jackrabbits Athletic Complex because Sanford Health -- a network named for Sanford, its central benefactor -- gave a $10 million lead gift with the rest coming from private sources.

"I think we all have a responsibility to give back to our communities," Dykhouse said. "That's something Denny Sanford taught me 20 years ago."