The Routes by Which Lake Superior Ores Go to the Furnaces
The first two mines, the Jackson and the Marquette, have come to be particularly well known historically. The development of these and other ranges in northern Michigan and Minnesota, particularly the Menominee, Gogebic, Vermillion, etc., and, since 1890, the Mesaba and Cuyuna, have brought about revolutions in ore digging, handling and transportation, which followed each other with extreme rapidity. The ore carrying boats, for instance, may almost be said to have jumped from a length of three hundred to six hundred feet, and the Sault Sainte Marie canal locks were several times almost immediately outgrown, though rebuilt again and again, each time so much larger than before that they were deemed impossible to be outgrown.
Loading Ore at an Open Pit Mine
Showing Other Typical Ore Bodies, Shaft Mined
Practically all of the ore beds, with the exception of the Mesaba, yield hard or lump ores and most of them are shaft mines in which mining has to be done underground and the ore blasted down. Blast furnaces had never used any but lump ores when along came discovery of the immense soft ore deposits lying just beneath the surface of the ground over a region one-hundred miles long in what is known as the Mesaba district of Minnesota. These soft ores were so accessible and so rich that they drew the attention of the iron makers of the whole country. But, alas! While perfectly good in every other respect, they were merely dry powder and not adapted to blast furnace methods. There were great discussion, excitement, and ridicule among or at those who invested in these soft ore mines. Eventually, of course, blast furnace men worked out feasible methods of converting soft or what are termed “Mesaba Range” ores into iron in the blast furnace. Those brave spirits, who in the face of ridicule dared to invest in and develop Mesaba properties, have long been reaping their financial reward which still shows no sign of diminishing, as “Mesaba Range” mines are “the” mines of to-day.
A Close View of the Hoover & Mason Unloaders