Constructed in 1889, the Bi-Metallic aerial tramway carried ore from the Blaine Shaft in Granite to the Bi-Metallic Mill in Kirkville, near Philipsburg. It was 9750 feet long with a vertical drop of 1225 feet, making it the longest aerial tramway in the United States at that time. The tramline used wooden towers with rollers and guides on the ends of both arms, and these rollers supported a very large moving cable to which the tram cars were attached. About the same time, the Granite Mountain Mining Company built a similar aerial tramway 8750 feet long to carry ore from the Ruby Shaft in Granite to the Rumsey Mill, or Mill C, to the east.