The main building on Carrie Furnace’s 80-acre site in Braddock looks like a giant has just scattered its playthings and stomped off, not too far away, to eat a few goats. Inside the blowing engine house a 48-inch universal plate mill lies in 40- and 50-ton pieces on the concrete floor. A sign hanging at the south end lists the safety guidelines (“6. Be aware of crane movements”). Bill Sharkey sits on a few benches meant for visitors. Sharkey isn’t a visitor, really. He worked as a foreman at