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 The newly dry dam site was still not ready for construction to begin. Like any large structure, Hoover Dam had to be built on a solid foundation of bedrock. Bedrock in Black Canyon lay buried beneath 135 feet of silt and stones that the Colorado had deposited over millions of years. The muckers who would dig it out had eight months of hard labor ahead of them. June 6, 1933, was the big day. The surface of the exposed bedrock had been swept and sponged until it was free of any traces of mud. Wooden forms, like rooms without ceilings or floors, were waiting in place on the bedrock at the very bottom of the dam site. The forms would hold the concrete in place until it hardened. The two long years of preparation were over. It was time to actually build the dam. Officials from Six Companies and the Bureau of Reclamation peered skyward as an enormous bucket of concrete swung gracefully through the air suspended from a steel cableway that stretched across Black Canyon. Photographers clicked their shutters as the bucket was slowly lowered an eighth of a mile to the bottom of the canyon. "Puddlers," workers in high rubber boots, waited in an empty form until it hovered in position next to them. Then, at a signal from Frank Crowe, they released the safety latches on the bucket's trap doors and jumped out of the way. Sixteen tons of wet concrete dropped in an abrupt glob into the form. Relieved of the weight, the bucket bounced skyward on its cable like a yo-yo. The puddlers leaped into action just as quickly with shovels and spreaders, stomping and smoothing the concrete, making sure there were no air bubbles to weaken it after it hardened. |