Ropes Gold Mine, Ishpeming Greenstone belt (Marquette .
An old caved-in Michigan copper mine shaft that has been secured with new steel posts and barbed wire. An old open Michigan copper mine shaft that has not been secured in any manner and that poses a threat to the unwary. A well secured mine shaft at the Minesota Mine, Ontonagon County, Michigan. Sections of steel rails have been fastened in .The problem of delineating the boundaries of these old mines is multifaceted. In most cases, entry is precluded by flooding, caving, or extremely unsafe conditions below ground. In many cases the company that did the past mining has gone out of business, or the old mine maps were incomplete and/or inaccurate, or are missing.