Photos of the buildings at the portal of Armstrong tunnel. The first photo is from 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. The second photo is from 1939, showing the 'I' Bridge being built, with the Bingham Metals ore bins already in place. The third photo is from 1941 and shows the original loading bins, plus the second loading bins built by Bingham Metals after they had moved their surface facilities in 1931. Note that the buildings in the 1930 photo match the buildings in the closer of the two loading bins in the 1941 photo. The steel railroad bridge in the 1941 photo, known as the 'I' Bridge, was built in 1939.

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