In 1973, when the dam was only half built, but almost $5 million had already been spent on the project, large, open fissures were encountered during excavation of the keyway trench near the right end of the dam, about from the canyon wall. The two largest, near-vertical fissures trended generally east-west and extended more than below the bottom of the key trench. Some of the fissures were lined with calcite, and rubble filled others. Several voids, as much as wide, were encountered below the ground surface beyond the right end of the dam and grout curtain. The largest fissures were actually caves large enough to enter. One of them was wide and long. Another one was wide in places and long. These were not grouted because they were beyond the keyway trench and beyond the area where the bureau had decided grouting was required. This necessitated using twice as much grouting as had been originally anticipated; the total injected grout included 496,515 ft3 of Portland cement, 82,364 ft3 of sand, 132,000 pounds of bentonite, and 418,000 pounds of calcium chloride, injected into 118,179 linear ft of drilled holes.