U.S. Steel’s Mon Valley Works is what is known as an integrated steel-making operation. That means U.S. Steel starts with raw materials – iron ore, coal, etc. – and produces finished steel.
The Edgar Thomson facility makes molten iron (or pig iron) in its blast furnaces using coke from Clairton, iron ore, and other materials. Within the blast furnace casthouses, the furnaces are tapped and the pig iron is collected in rail cars (called torpedo cars) for transfer. A molten sulfurous metallic waste product of the blast furnace is slag, which is diverted into open pits to cool before processing.
The facility turns iron into steel by way of the basic oxygen process (BOP) in a part of the mill aptly named the BOP shop. Molten steel is poured into a continuous caster that creates steel slabs, which are then shipped by rail to the Irvin Works for finishing.
Edgar Thomson Investigation
A four-part series examining the years-long fight to get U.S. Steel’s Edgar Thomson facility in North Braddock in compliance with a host of air quality rules and regulations
