The Oak View Group (OVG) and the Seattle Hockey Partners (SHP) investment group released a detailed explanation on how they plan to dig down at Seattle Center and double the size of the current KeyArena footprint.

On Tuesday, a detailed animation of the project was released, a current part of a memorandum of understanding with the city of Seattle, as the lead contractors for the project were announced.

Skanska and AECOM Hunt will be the joint construction contractors for the $700 million, privately financed arena at Seattle Center. Construction will involve digging an additional 15 feet down in the KeyArena site to help create a 750,000-square-foot sports and entertainment complex at Seattle Center.

The price is significantly larger than what AECOM once projected a renovation on the site could cost during a study back in 2015. The company bought Hunt Construction, which, along with Skanska, will take on what OVG calls the "largest private investment in Pacific Northwest sports and entertainment history.”

The construction is pending final approval of transaction documents and final permitting from the city of Seattle. The final environmental review is due in August, with a final Council vote in September. If approved, construction would begin in October.

The newly released animation shows how Skanska and AECOM plan to stabilize the existing roof and then dig down to build out the new bowl. Most of the expansion will occur on the south side of the bowl and the KeyArena roof will be preserved. The new bowl would allow for 17,300 fans for hockey, and 18,600 for basketball games.

WATCH: Oak View Group arena construction animation

"Today’s announcement adding Skanska-Hunt to this world-class project team is just another step in a defining moment for our city as we continue to move toward the resurgence of the Seattle Center,” said Tod Leiweke, president & CEO of Seattle Hockey Partners. “Visitors for the sports and entertainment events are going to be treated with a venue that not only honors the history of the arena but also provides the latest in arena and fan engagement technology. No matter if you’re here to see the Seattle Storm, a hockey game or a concert, the new Seattle Center Arena will deliver amazing fan experiences.”

Skanska and AECOM both have significant history in arena and stadium construction, including MetLife Stadium, where the Seahawks won their Super Bowl title, and the recently developed Mercedes Benz Stadium in Atlanta, T-Mobile Arena in Las Vegas, and Little Caesars Arena in Detroit.

AECOM Hunt claims 150 stadium construction projects to their name. CAA Icon and architect Populous are still part of the project, and multiple local labor unions have also signed on to build the project.

The building will hold "140 events per year, with a goal of becoming one of the top 10 music venues in the country,” OVG and SHP said in a release.

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“The Seattle Center Arena project will deliver a new, modern entertainment venue to the city and enhance the urban character and heritage of Seattle Center,” CAA Icon CEO Tim Romani said in a prepared statement.

Populous Principal Chris Carver stressed that the design was made to include basketball, which has been a sticking point for observers of the project.

“The redevelopment is focused on creating a home for a variety of events that will appeal to an entire cross-section of the Seattle community. It is designed specifically for each and every one. For fans, this means providing a myriad of seating options and a redesigned seating bowl with strong sightlines for hockey, basketball, concerts, and more to truly become a place where people love to be together.”

Also see: Former Sonic Durant, Warriors to play last game at KeyArena

The privately financed deal and redevelopment at Seattle Center would finally draw a close to a more than decade-long debate about the future of KeyArena.

The NBA's Sonics vacated the building back in 2008 after the then ownership complained about the lease terms and sight lines. The city of Seattle agreed to the departure to pay off the then-debt load on the building. It was slated for a minor fix as part of the deal to build a SoDo Arena in 2013. But once that deal expired the city struck a new one with OVG for the massive redevelopment, which also includes money for transportation and civic groups like YouthCare. The transportation mobility plan is scheduled to be released before a final Seattle City Council vote.

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Seattle Hockey Partners has an application to the NHL for an expansion franchise to begin playing in 2020 when the new building would be scheduled to open. SHP is also exploring land options to build a practice facility and team headquarters. The NHL could vote in late September or early October on whether to award the league's 32nd team to the Emerald City and the new building.