One of the Mack trucks in front of the upper portal of Diversion Tunnel #2. This truck has 9 cubic yards capacity. Note the steel canopies over the driver's heads on all the trucks. Jan. 28, 1932.
A flashlight photograph of the interior of one of the diversion tunnels. The drilling jumbo is working at the tunnel face. The 12' by 12' top-heading can be plainly seen. January 28, 1932.
One of the drilling jumbos ready for action. This view was posed outside the tunnel, just as the swing shift was ready to go to work on the upper portal of Diversion Tunnel #1. January 28, 1932.
Drilling jumbos (aka Williams Jumbo) mounted on the back of a truck for starting construction of lower portal No. 4, Arizona side of Black Canyon. 9-26-31. (This first wood-frame jumbo was experimental - the jumbos later were steel pipe)
Looking up Black Canyon from a point below all the lower portals, showing the Government pumping plant (lower left), the Six Companies' compressor plant (middle left), the location of the lower portals, & the highway loop above the canyon wall (upper center) - 7/30/31.
p.16 #1074 Scaling down canyon wall, in excavation for intake tower on Nevada side. Apr. 1, 1932. p.16 #1073 Close-up of No.1074 to the left. Workmen are 700 feet above river. Apr. 1, 1932.
Pg.43 #2789 Boulder Dam, looking upstream from Lookout Point. July 31st, 1934. Pg.43 #2777 Looking downstream at Boulder Dam, from the Arizona side. July 24th, 1934.