The purpose of a logging dam is to help logs flow down a shallow river. A pool of water would be built up in late fall, and it would freeze over in the winter. Oxen would be used to drag the logs onto the ice. When the ice melted, the logs would end up in the water. Then periodically during the summer, water would build up behind the dam, and loggers would release a wave of water and a group of logs. The wave of water would help carry the logs down the shallow ever and over rapids.
The first dam structure was built here in 1853. It was improved over time, which is somewhat unique for a logging dam. Normally, they are built quick and cheap, used one or two seasons, and then the timber is played out. In the case of the Coppermine Dam, a rail spur was built to the dam in 1889 by the Empire Logging Company. They had a stand of virgin pine in Douglas County that was logged over a period of 7 years. The timber would be cut, then floated on the Black River north towards Pattison Falls. There the logs would be collected and loaded onto train cars. The train would bring the logs down to the Coppermine Dam, and dump them into the pool behind the dam. The logs would them be floated down river to the Empire Mill in Winona as water levels would permit.
Today, the Coppermine Dam is abandoned. It is well out in the wilderness in a National Forest, so it sees very few visitors. The rock cribs have long since rotted and broken open, spilling the rocks in big piles across the river. Some of the timbers remain, but most have been dislodged by the winter ice. The dike on either side of the river is still in very good condition. While the dam once had a 6 foot waterfall, the river falls about a foot or foot and a half at this location today.
