The firm that built Target Field for the Twins and the U of M’s TCF Bank Stadium will be the construction manager on the Vikings new stadium. The Minnesota Sports Facilities Authority on a unanimous vote Friday morning selected Golden Valley-based Mortenson Construction for the $975-million project. Mortenson was chosen because they have national sports construction experience, local connections, offered the most competitive fee, have staff experience with operable roofs and a proven track record of hiring a diverse workforce. Mortenson estimates the project will employ 7,500 workers. Officials plan to break ground on the new stadium this October. The Vikings are now planning to play one more season at the Metrodome and two full seasons at TCF Bank Stadium. The tentative plans now are to tear down the Dome in February of 2014 and for the new stadium to be ready by July 2016.