Before and during construction, workers and engineers experienced problems. Contracts for companies to construct the various parts of the dam were difficult to award as few companies were sizable enough to fill them. This forced companies to consolidate. In addition, Native American graves had to be relocated and temporary fish ladders had to be constructed. During construction additional problems included landslides and the need to protect newly poured concrete from freezing. Construction on the downstream Grand Coulee Bridge began in and more considerable earth-moving began in August. Excavation for the dam's foundation required the removal of 22 million cubic yards (17 million m³) of dirt and stone. To reduce the amount of trucking required in the excavation, a conveyor belt nearly long was built. To further secure the foundation, workers drilled holes into the granite and filled any fissures with grout, creating a grout curtain. At times, excavated areas collapsed from overburden. In order to secure these areas from further movement and continue excavation, diameter pipes were inserted into the mass and chilled with cold liquid from a refrigeration plant. This froze the earth and secured it so construction could continue.