"My goal is to see Pennsylvania become an energy capital, a major player in the world," Corbett said. "This is a major step toward that."
Union leaders also praised the agreement. Members were scheduled to vote on a new contract later Monday.
"Not only will good paying manufacturing jobs be saved, but new ones will be created as this vital facility is improved and expanded," United Steelworkers president Leo Gerard said.
___Associated Press writer Marc Levy contributed to this report from Harrisburg, Pa.