National Register of Historic Places in San Juan County
The Shenandoah-Dives Mill, which was constructed in 1929, is an exceptionally intact example of a selective flotation mill reflecting the distinctive characteristics of hard-rock milling processes in the early 20th century Rocky Mountain West. It is also the only intact and functional late 1920s-era, wooden gravitational selective flotation mill in Colorado.
Quoted from the History Colorado website.