National and State Register

Cardinal Mill

Boulder County

The 1901 Cardinal Mill is significant for engineering and industry as an outstanding example of a concentration facility as defined in the Mining Industry in Colorado Multiple Property Listing, and Amendment to Metal Mining and Tourist-Era Resources of Boulder County Multiple Property Documentation Form (MPDF).  The mill was important to western Boulder County, contributing to a highly productive tungsten ore operation until 1942. 

A photo of the mill, running down the incline with sloping windows and white-trimmed windows.

Cardinal Mill 

Additionally, the Mill is architecturally significant as an excellent example of a vernacular concentration mill common in the Rocky Mountains between 1901 and 1940.  The building is vernacular in that it was not designed by a professional architect and was instead constructed with available materials and planned in the field to meet specific needs of the operation in the mountain environment.  Overall, the building retains character-defining features including the stair step roofline, profile, and plan typical of Rocky Mountain ore concentration mills, few of which remain intact.