Statement of Significance (as of designation - February 16, 2000):
The Shenandoah-Dives Mill is an intact and fully functional mill and includes all of its original equipment from the early 20th century.
Constructed in 1929, the Shenandoah-Dives Mill is the finest extant example of a selective flotation mill. This property illustrates the transformation of the mining and milling industry and the distinctive characteristics of the hard-rock milling process during the first half of the twentieth century. Flotation, introduced to the American mining industry in 1912, was an innovative concentration process that separated valuable minerals from complex ores. This process efficiently and economically concentrated complex ores that were practically impossible to treat by earlier methods. The flotation process solved the problem of diminishing high-grade ore supplies and allowed increased minerals production.