Mineral-resource assessment of the Iron River 1° x 2° quadrangle, Michigan and Wisconsin

The Iron River 1° x 2° quadrangle contains identified resources of copper and iron. Copper-rich shale beds in t1n north part of the quadrangle contain 12.2 billion pounds (5.5 billion kg) of copper in well-studied deposits including 9.2 billion pounds (4.2 billion kg) that are economically mineable by 1980 standards. At least several billion pounds of copper probably exist in other parts of the same shale beds but not enough data are available to measure the amount.

A small amount, about 250 million pounds (113 million kg), of native copper is known to remain in one abandoned mine, and additional but unknown amounts remain in other abandoned mines.

About 13.25 billion tons (12.02 billion t) of handed iron-formation averaging roughly 30 percent iron are known within 500 feet (152.4 m) of the surface in the Gogebic, Marquette, and Iron River-Crystal Falls districts. Some, probably small, percentage of that might someday be mineable as taconite, but none is now believed to be economic. Some higher grade iron concentrations exist in tin same iron-formations. Such material was the basis of former mining of iron in the region, but a poor market for such ore and depletion of many deposits has lead to the decline of iron mining in the quadrangle. No iron mines of the quadrangle were being worked in 1981.

Many parts of the quadrangle contain belts of favorable host rocks for mineral deposits. Although no deposits are known in these belts, undiscovered deposits of copper, zinc, lead, silver, uranium, phosphate, nickel, chromium, platinum, gold, and diamonds could exist.