The Broncos have finalized a sale agreement to purchase Burnham Yard from the Colorado Department of Transportation as the proposed location for a new stadium and mixed-use entertainment district. The NFL team agreed to pay $45.8 million to acquire roughly 58 acres from the transportation agency in March. The deal is expected to close this fall. It is the formalization of a “conceptual agreement” the Broncos made back in September to buy the historic railyard located south of Colfax Avenue and east of Interstate 25. The finalized deal — giving a limited liability company associated with the Broncos the right of refusal to purchase Burnham Yard — was signed May 21. The state had purchased the land in 2021 for $50 million. “As part of the sale process, the state received the proceeds that will ensure our obligations to lenders are fully covered,” CDOT spokesperson Matt Inzeo told The Denver Gazette.…