Ice and Mathematics

Ice on the Great Lakes is the heaviest in the memory of the oldest oldtimers. Some venerable head-shakers glumly predicted, "There won't be much doing on Superior before the middle of May."

The great Soo Locks at the eastern tip of Superior and the narrow Straits of Mackinac that connect Lake Michigan with Lake Huron are the twin bottlenecks through which 85% of the nation's vast iron ore production flows to U.S. blast furnaces. The ore moves eastward to the Soo from Minnesota's Mesabi Range, then southwest to Gary, southeast to Cleveland, Youngstown...

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