In 1870, the Montreal Mining Company sold their failed silver mine to the Silver Islet Mining Company, believing it wasn’t worth the hassle. The shafts extended down about 1,250 feet into Lake Superior, taking advantage of silver deposits in the bedrock along the way. But because the shafts dove into the lake, the mine workers constantly needed to run pumps to get rid of the water that flooded them day in and day out.
The owner of the Montreal Mining Company made a big mistake that day. After Silver Islet Mining Company took over, the site became one of the most profitable silver mines in the world, producing roughly $3,250,000 of silver ore. The mine closed just 13 years after it opened, when a shipment of coal required to keep the pumps going never arrived and Lake Superior reclaimed the shafts.
Those shafts are still there today, flooded by the lake and available to float over on a boat. It makes for a pretty spooky picture—a mine shaft descending deep into the depths of Lake Superior. Several shafts are visible, as well as the ruins of old mining buildings.
