Kennecott Copper Corporation, Concentration Mill, On Copper River & Northwestern Railroad, Kennicott, Valdez-Cordova Census Area, AK

Significance: The Concentration Mill was a dynamic, ever changing structure. Its form reflected the ever-increasing complexity of the ores mined at Kennecott. The building was first erected in 1908 as the lower terminal of the Bonanza Aerial Tramway. Storage bunkers and loading facilities below the tramway served as the necessary link between the mines and the railway. Shipments of high-grade ore started in 1911.
Unprocessed Field note material exists for this structure: N1049
Survey number: HAER AK-1-D
Building/structure dates: 1908 Initial Construction
Building/structure dates: 1912 Subsequent Work
Building/structure dates: 1915 Subsequent Work
Building/structure dates: 1923 Subsequent Work
Building/structure dates: after. 1950- before. 1959 Subsequent Work
National Register of Historic Places NRIS Number: 78003420