Silver Islet was one of Canada’s most profitable silver mines, until it was destroyed by a storm over Lake Superior
Located on a small rocky island just off the northern shore of Lake Superior, Silver Islet mine was once the most lucrative silver mine of its time – until it was swallowed by the raging waters of the lake.
For 13 years, it provided some of the highest quality silver in the world. Large nuggets of the metal were discovered there, some so pure they did not need to be smelted. Over the course of its lifetime, the mine produced 2,605,786 ounces of silver, worth $3.25 million.
The Montreal Mining Company first started digging for its treasure in 1868. Developing the mine was not easy, however, and the unpredictable nature of Lake Superior made it an engineering nightmare to maintain.
After two years of trying to collect silver from the mine, the Montreal Mining Company sold it in 1870 to Alexander H. Sibley, who created the Silver Islet Mining Company to advance the project.
To protect water from inundating the mine shaft, head engineer William B. Frue designed a break wall – a massive fortress of wood and stone to act as a barrier to the fury of the lake’s storms – along with pumps to keep the water out.
In the book Silver Islet: Striking it Rich in Lake Superior by Elinor Barr, Frue was said to have likened the effects of a storm to a military siege: “It seemed as though the water would surely succeed in regaining the whole of its territory and in driving its invaders from the ground.”
Workers had to travel 384 metres into the Earth every day – comparable to climbing by ladder down the length of the Empire State Building.
For the rest of this article: http://magazine.cim.org/en/mining-lore/lake-superiors-silver-island-en/