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 river and over any 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, then used one or two seasons before 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 then be floated down river to the Empire Mill in Winona as water levels would permit.
The photo above is an overview of the dam site as it sits today. The rock cribs have long since rotted away 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 at this location today.
The Coppermine Dam is deep in the wilderness in a National Forest, so it sees very few visitors. The old railroad right-of-way runs for about 12 miles from the nearest paved road. The right-of-way is easily passable when dry by high clearance vehicles such as pick-up trucks and SUVs. The trail to the dam is located shortly before the railroad bed comes to an end. The trail to the dam site is a bit overgrown, but is still an easy hike.