The iron ore at the bottom of the Steep Rock Lake in northwestern Ontario was 90 feet below water level. To get to the rich iron ore body, 70 billion gallons of water, 300 feet of glacial silt and sand and 100 feet of boulder clay had to be removed in order to reach high quality iron ore. This view below shows dredging an open pit mine at Steep Rock circa 1940 (C.J. Humber Collection)