ArcelorMittal had its best quarter — a $1.1 billion profit over the last three months — in a year and a half, but it's still looking to shrink its steelmaking capacity locally at a time U.S. mills are running 30 percent below their potential.

"In the labor agreement ratified, we are now progressing with our footprint optimization project at Indiana Harbor," ArcelorMittal Chairman and Chief Executive Officer Lakshmi Mittal said during a conference call with investors a week ago. "In a small simple term, this is about idling less competitive finishing assets while making important investments in more efficient asset to improve the configuration of the Indiana Harbor plant."

ArcelorMittal should save $200 million a year after shuttering the 84-inch hot strip mill and other finishing lines in East Chicago. Displaced workers are being given the chance to transfer to open positions in Indiana Harbor, Burns Harbor and Riverdale.

The United Steelworkers union agreed to the idlings in its new contract, to help the steelmaker become more competitive in a tough environment.

"At the same time, we have an investment program to invest in steel shop and discussing to optimize the footprint of Indiana Harbor and some of the other sets in U.S.," Chief Financial Officer Aditya Mittal said. "We have said during this that this will give us a benefit of about $200 million from 2017 onwards, but some of the benefits will also come this year. Maybe close to $50 million to $100 million, we are not sure yet."

ArcelorMittal executives are getting more optimistic about the U.S. market, where prices have risen to around $687 a ton in July, according to the trade publication Steel Benchmarker.

"In terms of import pressures, I think look in terms of the U.S. marketplace our view is still constructive," Aditya Mittal told investors during the conference call. "Supply demand balance is quite constructive, inventory levels remain low and so far we are seeing some stability in pricing with some downside risk."