The Seven Iron Men, also known as Merritt Brothers, were iron-ore pioneers in the Mesabi Range and the creation of what is now known as Mountain Iron. In the late 1800s, the Merritt family founded the largest iron mine in the world and initiated the consolidation of the American railway system into what would ultimately become the United States Steel Corporation. Their story was told, in part, by the book Seven Iron Men by Paul de Kruif. The book was first published in 1929.
The brothers, actually five brothers and two nephews, charted the Mesabi Range and recorded the areas that demonstrated the highest potential for iron after they recognized what they had found. Due to the lack of railroads in the region, they were initially unable to transport the ore, but their discovery catalyzed the growth of railroads in the region. The railroad became the center of conflict between the Merritt Brothers and J.D. Rockefeller, to whom they were eventually forced to sell their stake in Mountain Iron in 1893.
The primary figure of the Merritt family was Leonidas. He was born in Chautauqua County, New York where he lived until age 7 when he moved to western Pennsylvania until age 12. In 1856, his family moved to live in a community of five or six families in Duluth, Minnesota, just after the 1854 Treaty of La Pointe transferred land from the Indians and where his father, Lewis H. Merritt, worked as a lumberman and a millwright. He joined the Army to fight in the Civil War and returned after his father had failed to discover gold in the Vermillion or Mesabi Mountain Ranges. The black "banded ore" rocks that his father brought back to Duluth from the Mesabi Range convinced Leonidas to explore the Mesabi Mountains.
Mesabi is an Indian word meaning "the grandmother of them all," that divides the water flowing into the Hudson Bay from the water flowing into Lake Superior. Geology professor Van Hise had proposed a "trough theory," explaining how the mountains potentially contained ore-filled troughs at various places. Leonidas developed a magnetic survey and mapped out the ore troughs in the area. With money saved 16 years working as a lumberjack, Leonidas bought land for $1.25 an acre and opened what became the largest iron mine in the world, Mountain Iron Mine.