Big Dan Mine

Big Dan Mine is an abandoned underground mine in Northeastern Ontario, Canada. It is located about 1 km (0.62 mi) southwest of Net Lake and just west of the Ontario Northland Railway in east-central Strathy Township. It is named after Dan O'Connor, who first claimed the site in the 1890s.

Mining operations began at the site in the early 1900s, making Big Dan one of the oldest mines in Temagami. Gold and silver were the mine's primary commodities, while arsenic was a secondary commodity. A forest fire destroyed much of the mining infrastructure on the site in 1907. Active mining operations on the site ceased following the fire, but mineral exploration has occurred there periodically since. Mineral exploration at Big Dan remained idle from the early 1970s to the early 1990s as a result of a land claim dispute applied by Temagami First Nations.

The mine consists of two shafts, an open cut and an adit. It is surrounded by a large boreal forest that covers much of the Temagami region. Basalt is the primary rock type at Big Dan, forming part of the Arsenic Lake Formation, the site's major geologic feature. A small zone of deformation intersects the local basaltic bedrock, which is the location of several minerals.