|The Bonanza Mill is an inactive mill site located in Stevens County, Washington. The mill processed ore from the Bonanza Mine, an inactive lead and zinc mine also located in Stevens County, Washington. The site is located between Highway 395 and the Colville River. The site is currently used for timber storage and for loading and unloading timber transport trucks. |
Operations at the Bonanza Mill site included a 100-ton flotation mill that processed ore transported by rail from the Bonanza Mine. Typical flotation processes can include amalgamation, leaching, and/or flocculation, all of which utilize inorganic compounds, including mercury. Tailings from the mill were discharged to a lagoon, separated from the Colville River by a gravel and sand dike. Process water discharged to the lagoon evaporated or infiltrated through the soil. Operations at the mill coincided with the mine operations, which began in 1885 and continued until the mine closed in 1952. No information has been discovered regarding operations at the site between 1952 and 1999.