The Coppermine Dam is a very common style of logging dam. To build the dam, loggers built wooden cribs on the ice in winter, then filled those cribs with rock. When the ice melted, the cribs sank to the bottom and acted as piers. Additional pilings were sometimes driven, but that was limited by the lack of heavy equipment. Once the cribs were in place, timber was used to build the face of the dam. Gates would also be installed to allow the loggers to control the water flow.

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.

These two photos are views of the remains of the Coppermine Dam. The rocks once formed key components of the dam foundation. They were held in wooden cribs, and anchored the dam gates. The gates have been salvaged, while the cribs rotted away spilling the rocks. The photo above is a view of the downstream face of the dam. The photo below is a view looking across the two channels that once formed the log sluices. Both photos are looking west from the east side of the ruins.

The photo above is water flowing over a timber that is remains from the dam structure. The photo below is a view of the river behind the remains of the dam.

These two photos are view of the dam embankment on the east side of the Saint Croix River. The embankment ran for several hundred feet. The trail leading to the dam runs along the top of this embankment. The photo above is looking to the east, while the photo below is looking to the west.