Ruby Mine and Mill - Nighthawk Mining District
The Ruby discovery in April of 1902 is credited to A.M. Riste and George Bowers, who then sold the property in November of the same year to Ruby Mining Company, Inc. Hagerty (1905) stated that in the first full year of development, 1903, the mine produced about $20,000 in silver values from the initial 211 feet of adit.
In 1915, the Pyrargyrite Mining Co. Inc. purchased the mine (Patty, 1921). Patty reported that from 1915 to 1920 Pyrargyrite Mining shipped “…31 railcars of crude ore showing a gross value of approximately $25,000.” Working backward from the price of silver at that time of 60 cents per ounce, the shipments would amount to about 1240 tons containing 44,640 ounces of silver—indicating a not inconsiderable grade of 35 opt silver for what was probably hand-sorted ore.
The 75 ton per day (tpd) mill built by Pyrargyrite Mining was completed in the summer of 1920. It used both flotation and gravity separation. The first year of mill operation was 1921, when it probably processed stockpiled ore. The mill was well equipped with the best available mineral dressing equipment known at the time.
Source: Washington Division of Geology Information Circular 111 Fritz E. Wolff, Donlad T. McKay, and David