U.S. Steel plans to spend at least $750 million to upgrade a century-old steel mill along northwestern Indiana's Lake Michigan shoreline. Company and government officials said Thursday that the project will help preserve Gary Works' nearly 3,900 steelworker jobs, and could help ensure the 112-year-old mill lasts another century. The company had been criticized for not spending enough on equipment at mills such as Gary Works during the steel industry's recent downturn.