“This is a truly transformational investment for U. S. Steel. We are combining our integrated steelmaking process with industry-leading endless casting and rolling to reinvest in steelmaking and secure the future for a new generation of steelworkers in Western Pennsylvania and the Mon Valley,” U. S. Steel president and chief executive David B. Burritt said in a statement.

“U. S. Steel’s investment in leading technology and advanced manufacturing aligns with our vision to be the industry leader in delivering high-quality, value-added products and innovative solutions that address our customers’ most challenging steel needs for the future.”

U. S. Steel said the new strip mill link the caster and rolling mill through an endless casting and rolling process. Burritt told the Pittsburgh Post-Gazette newspaper that the new mill will be one of a kind in the United States.

The company also said the mill will make the Mon Valley Works the principal source of substrate for its XG3 brand of advanced high-strength steel. 

As part of the project, U. S. Steel said it also intends to build a cogen plant at the Clairton facility. The new plant, which will be equipped with state-of-the-art emissions control systems, will convert a portion of the coke oven gas into electricity to power the steelmaking and finishing facilities in the Mon Valley.

U. S. Steel revealed the project during an event at the Edgar Thomson Plant. The event drew U. S. Steel employees, local and state officials, and union leaders.

USW International President Leo W. Gerard said he applauded U.S. Steel's investment decision.

"Almost 127 years after the Battle of Homestead, U.S. Steel seems to understand that the ultimate measure of the company's success cannot be calculated just in profits and share price," Gerard said.

"This investment demonstrates a commitment to operate in the best interests of its employees and their communities and shows respect for the part our members, their families and neighbors have played in keeping the proud tradition of steelmaking alive in the Mon Valley for over a century."

U. S. Steel has more details about the project here.