Chippewa Indian Legends of an Ancient White Race of Copper Miners
The copper was mined on an industrial scale. One researcher wrote that the Isle Royale mines would have required 10,000 men working a thousand years to remove that much copper www.nephilimgiants.net : Six Ton Piece of Copper is Raised out of a Lake Superior Mine: Evidence of Mediterranean Copper Mining
Prehistoric Copper Mining in the Lake Superior Region, 1923
These prehistoric miners left no records that we can translate to tell who they were. Apparently, they did not winter in the region and apparently, too, none but the hardy and strong made the trip. No Graves have been found which can be definitely ascribed to them. They made no drawings, no carvings, and left nothing in the way of mounds, ceremonials or otherwise, to indicate their lineage. The pits and the tools are all and they are not enough.
Father Allouez said that the Indian legends contained no reference to mining or the miners. In fact, the Indians did not know where the mines were. A report of a Chippewa legend says that the old one states that their forefathers, drove out a white race who might have been the miners.