Cobalt Lake Mine
| | Heritage Silver Trail Site #8 | |
The Cobalt Lake Mining Company Limited was granted ownership of the mineral rights to 47 acres under the bed of Cobalt Lake in December, 1906. Access to the workings was gained from shafts around the south edge of the lake.
Prospecting proved difficult because it all had to be done underground. Cross-cuts were driven to intersect the extensions of veins from the neighbouring properties. By 1909, over 5,000' of shaft sinking, drifting and cross-cutting had been done. Mining began and the first mill on this site was erected in 1911.
In 1914, Mining Corporation of Canada Ltd. acquired the property along with many other properties. Cobalt Lake was pumped out in 1915, and prospecting, mining and milling were carried out until 1932.
In 1932, blasting in the mine broke through the bedrock cap and an estimated 400,000 tons of mill tailings poured into the mine. No one was injured but the lower levels of the mine were filled with tailings and became unworkable.
Erected by Cobalt Historical Society.
Topics. This historical marker is listed in this topic list: Industry & Commerce. A significant historical month for this entry is December 1906.
Location. 47° 23.314′ N,
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Regionally, this marker is in Northeastern Ontario and specifically in Northern Ontario. It is also in Central Canada. Globally, it is in North America, the Great North Woods, the Western Hemisphere, the Western World, and the Anglosphere. Historically, it finds itself in what was once a British colony, the Viceroyalty of New France, the Haudenosaunee (Iroquois) Confederacy, and Ruperts Land.
Other nearby markers. At least 8 other markers are within walking distance of this marker: Tri-town Trolleys (approx. 0.3 kilometers away); The McKinley-Darragh Story (approx. 0.3 kilometers away); Tunnel to Riches (approx. 0.3 kilometers away); Early Prospecting Techniques (approx. 0.4 kilometers away); Nipissing High Grade Mill
Also see . . . Cobalt Lake Mine and Hellens Mill (Cobalt Historical Society).
Excerpt: 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 1.3 meters wide.(Submitted on July 8, 2026, by Cosmos Mariner of Cape Canaveral, Florida.)Since 1907, mills have been depositing tailings into Cobalt Lake, and with improvements in silver recovery, companies have gone back and processed 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 Corp. took over the Hellens operations 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 of 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.
Credits. This page was last revised on July 8, 2026. It was originally submitted on July 7, 2026, by Cosmos Mariner of Cape Canaveral, Florida. This page has been viewed 10 times since then. Photos: 1, 2, 3, 4, 5, 6. submitted on July 8, 2026, by Cosmos Mariner of Cape Canaveral, Florida.
