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Signs erected by the insurance department of Six Companies, Inc., near the River Camp, approximately one mile upstream from the Nevada diversion tunnels. 08/09/1931...Show more
Signs erected by the insurance department of Six Companies, Inc., near the River Camp, approximately one mile upstream from the Nevada diversion tunnels. 08/09/1931
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The first step in driving the 56-foot diameter diversion tunnels on the Hoover Dam project was the construction of pilot tunnels. These are 12x12 feet and were later e...Show more
The first step in driving the 56-foot diameter diversion tunnels on the Hoover Dam project was the construction of pilot tunnels. These are 12x12 feet and were later enlarged to the full diameter of 56 feet. 08/26/1931
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Apparatus devised for drilling grout holes through the concrete lining of the diversion tunnels. Air drills are mounted on bars. The grouting jumbo travels on rails la...Show more
Apparatus devised for drilling grout holes through the concrete lining of the diversion tunnels. Air drills are mounted on bars. The grouting jumbo travels on rails laid on the invert floor. 07/23/1932
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