Armstrong Tunnel in 1930 when it was solely a Utah Copper operation, and before the tunnel was extended into the Bingham Metals ground, as well as being before ASARCO took its lease of the Armstrong mine.

Armstrong Tunnel in 1939 , showing the 'I' Bridge being built, with the newer Bingham Metals ore bins already in place. Note the fresh metal color of the Bingham metals ore bins.

Armstrong Tunnel in 1941, showing the original loading bins, plus the second loading bins built by Bingham Metals after they had moved their surface facilities in 1931. The steel railroad bridge in this 1941 photo, known as the 'I' Bridge, was built in 1939.