3.-1910-plant’s-12-inch-rolling-mill.-reroling-old-rr-rails-into-streel-for–reinforcing-concreteWEB August 30, 2014 1200 × 789 Seattle Then & Now: The Youngstown Steel Mill This dark interior of the early plant’s 12-inch rolling mill dates from about 1910. We can imagine the mix of warm light from the furnaces with the cool blue light falling from the mill’s high windows.