"Work was being carried forward during November 1931 on both upper and lower faces of all Diversion Tunnels except Diversion Tunnel § 1, the inside tunnel on the Nevada side. Both upper and lower portals of this tunnel were started during December, 1931.
# 754 The first stages in opening the lower portal. Workmen in the foreground are excavating the approach cut to the tunnel. The bench has been excavated in the background. December 8th, 1931.
# 715 Same as # 754, to the left. The portal has been excavated 56 feet in width and 41 feet high, and the tunnel has been advanced over 400 feet. January 1st, 1932.
§ 705 A comparable view to § 754, above. First attack is being made on the upper portal. December 24th, 1931.
# 718 Same as § 705, to the left. January 1st, 1932"