Summary of the estimated iron resources of the Marquette and Gogebic Iron Ranges of Michigan

The U. S. Geological Survey in cooperation with the Geological Survey Division of the Michigan Department of Natural Resources has recently completed detailed studies of iron-bearing rocks in the Marquette and Gogebic iron ranges in the northern peninsula of Michigan. The study included mapping the surface distribution of the iron-bearing rocks over a period of nearly 20 years. During that time, much information in the form of more than 4,000 drilling records and maps of mine workings detailing the subsurface distribution of the rocks was obtained from mining companies. We have used this information to better our understanding of the long- and short-term iron resource base of the region.