U.S. Steel has said that the Mon Valley will soon see the improvements promised by Nippon Steel. 

The U.S. Steel board approved the investment plans this week. The company will submit a permit for a new slag recycler at the Edgar Thomson Plant in Braddock. 

That recycler will have to be approved by the Allegheny County Health Department, and should it be approved, the company will then finalize the engineering plan, with construction expected to begin in 2026. 

The project is expected to cost about $100 million. 

Nippon Steel pledges multi-billion-dollar investment in Pittsburgh

Earlier this year, the merger between Pittsburgh-based U.S. Steel and Japan-based Nippon Steel was officially approved. 

Nippon's Vice Chairman, Takahiro Mori, said in an open letter not long after the merger was approved, that the company was dedicated to bringing steel-making back to the United States and Pittsburgh. 

"On behalf of Nippon Steel and my new colleagues at U. S. Steel, you have my promise that we will work tirelessly to repay the trust you have put in us as we incorporate U. S. Steel into the third largest steelmaker in the world," Mori wrote in an open letter in the Pittsburgh Post-Gazette. "We may be newly minted members of your community in Western Pennsylvania, but we already feel a deep responsibility to do right by each of you who have helped us get here." 

Nippon also promised a $2 billion upgrade to the aging mill by 2028, to install a state-of-the-art hot strip mill. The company also promised to leverage $500 million to build a research and development center in the Pittsburgh region. 

Nippon will make good on its commitment to retain the name of U.S. Steel and keep the headquarters in Pittsburgh, but also move the U.S. Nippon headquarters from Houston to Pittsburgh.