Michigan Copper Mines
Besides masses of copper recovered through hand sorting the mine ran a small stamp mill to recover finer grained copper in ore that ran 3% In 1870 the rich massive copper had been worked out and the depth of the mine shafts had reached the limit of the hoisting equipment At the same time the price of copper dropped to $ 19 per pound down from a high of $ 55 in 1864 Rather than invest