Nuggets of silver were discovered in the gravel on this end of Cobalt Lake in 1903, but mining under the lake could not take place until 1906 when the Province of Ontario auctioned off the mining rights. The winner formed the Cobalt Lake Mining Company in 1906 and began to mine the veins under the lake from 1906 to 1914. These veins subsequently produced close to 7 million troy ounces of silver. The most productive of these veins was in a fault called the Cobalt Lake Fault. This rich vein was approximately 330 meters long, 130 meters deep, and up to 1.3 meter wide.
Since 1907 mills have been depositing tailings into Cobalt Lake, and with improvements in silver recovery, companies have gone back and reprocessed the tailings to recover the silver earlier operations left behind. The first attempt to do this was by Mining Corporation of Canada from 1917 to 1920. The second attempt was in 1951 by Hellens Mining and Reduction Co. who built a cyanide mill and processed about 110,000 tons of tailings. In 1953 Cobalt Consolidated Mining Corp. took over the Hellens operation and processed another 86,000 tons. The foundations you see at this site are the remains of that mill. The most recent and successful reprocessing took place between 1966 and 1969 by Agnico Mines Ltd. They drained the south end of the lake and recovered approximately 600,000 troy ounces of silver from the tailings. The tailings from this operation were deposited in the north end of the lake and now form the foundation for part of the Cobalt Park.
In 1932 the Mining Corporation of Canada blasted one of the mine drifts under Cobalt Lake in order to recover the silver left behind in the crown pillar. This resulted in the lake and tailings draining into the old mine workings under the lake. The ore in the crown pillar had been left behind by the Cobalt Lake Mine to keep the lake from flooding the mine. The only thing remaining on the site from the Cobalt Lake Mining company’s activities between 1906 and 1914 is a hoist and partial building to the west of the mill foundations.
The photo below shows the Hellens Mill and the drag line used in 1953 by Cobalt Consolidated to recover tailings.
21 Silver Street
Box 309, Cobalt, ON P0J 1C0
Tel: c/o 705-679-5555