A promise has been made for the Pittsburgh steel industry. Last week, U.S. Steel announced it was committing $100 million to a new slag recycler at the Edgar Thompson Works in Braddock. Any investment in the steel industry facilities throughout Western Pennsylvania is more than an investment in equipment and architecture and technology — or, at least, it feels like it. It has seen 150 years of production, with thousands and thousands of employees making the steel that made Pittsburgh famous. It is not clear yet whether the $100 million is part of that prior commitment or in addition to it.