The Hull-Rust-Mahoning mine established in 1892 in Hibbing is one of the largest open pit iron ore mines in the world, with a 1.5 by 3.5 mile footprint and depths up to 600 feet. It supplied as much as a fourth of all the ore mined in the U. S. during its peak production during WWI and WWII.

~ Photo Credit: University of Minnesota Duluth, Kathryn A. Martin Library, Northeast Minnesota Historical Collections