Q. How large are the highlines? A. The higher towers are 190 feet tall; the main cable is 4 inches in diameter and about 2,000 feet long. REFRIGERATION PLANT Q. Why is the refrigeration plant necessary? A. A large amount of heat is produced by the chemical action of cement during the setting of the concrete. The heat must be removed to prevent expansion and cracking of the concrete. The refrigeration plant supplies the slush ice and cold water necessary to reduce this heat. Q. How is the heat controlled? A. First, the aggregate is sprayed with ice water before going into the mixers. Second, slush ice, along with water, is used in mixing the concrete. Third, cold water is pumped through pipes embedded in the concrete to carry away the heat generated. Q. How long will cold water have to be pumped through the cooling tubes in the dam? A. Approximately 12 days immediately following placement of the concrete to prevent uncontrolled cracking. Then for about 52 days in the second stage, which may be many months later and which is for the purpose of assuring uniform shrinking of the huge concrete blocks. CONCRETE BLOCKS Q. How large are the blocks of concrete placed in the dam? A. They vary in size. The largest are 70 feet by 180 feet in area; all blocks will be 7½ feet thick. Q. Why are blocks used rather than building the dam as one solid piece? A. Primarily, block placement facilitates cooling of the concrete and controls cracking due to contraction of the concrete. After the blocks have set and cooled, a mixture of cement and water (called grout) is pumped under high pressure into cracks between the blocks to form one solid mass of concrete. PAGE, ARIZONA GENERAL Q. After whom was the town of Page named? A. The late John C. Page, who served as Commissioner, Bureau of Reclamation, from 1937 to 1943. Q. Was there a community on the site of Page prior to 1957? A. No, nothing but raw desert land like that now surrounding the community. CLIMATE Q. What is the elevation of Page? A. 4300 feet, or about 500 feet higher than the rim of the canyon. Q. What are the extremes of temperature in Page? A. 105 degrees in summer; 10 degrees in winter. ACCOMMODATIONS Q. Does Page have overnight accommodations? A. Yes, two modern motels are open year around. Q. Are there any restaurants? A. Yes, there are now four restaurants in Page. In addition, the contractor’s mess hall is open to the public. DPS, Utah General Depot, 5-61, 100M Transcriber’s Notes —Silently corrected a few typos.