CN-12-201-192NA Klamath Project - Oregon-California. View of pipe laying operation. The man in truck helps push cinders into the conveyor unit. The man on the hopper unit keeps cinders moving smoothly by picking out oversize and filling voids that develop under the screen. The cinders are placed in the bottom of the trench by the hopper to form an envelope around the plastic drainage tubing; November 1972; Bureau of Reclamation photo by D. W. Stein