Steel Dynamics plans to upgrade its northeast Mississippi steel mill and add 45 jobs at the plant. : Indiana-based Steel Dynamics plans to invest $230 million to upgrade its northeast Mississippi steel mill, creating 45 jobs. The company, headquartered in Fort Wayne, said it plans to spend $140 million to add more galvanizing capacity to coat steel with rust-preventing zinc. Steel Dynamics said it has unmet demand for galvanized steel. Steel Dynamics said it will also invest $90 million to $100 million to increase production of high-grade steel for automakers and others.