Mill A and B

The Granite Mountain Mining Company constructed two mills adjoining the mining operation known as the Ruby Shaft. Mill A and Mill B housed a total of 70 stamp mills that processed ore by crushing it so metal could be separated from the base material by amalgamation of mercury. The stamp mills were very noisy and produced a great deal of dust, and the mines and mills operated six days a week. When production from the Ruby Shaft exceeded the capacity of Mills A and B in 1889, the company built a mill in Rumsey to handle the additional ore and named it Mill C.

Montana · United States