National Geographic : 1954 Oct
© National Geographic Society 543 Kodachromes by National Geographic Photographer Volkmar Wentzel Daring Pilots, Skittering Through Canyons Like Dragonflies, Chart Rimrock Deposits Nature has provided her own uranium test borings in the Colorado Plateaus; mineralized zones exposed by erosion on steep cliff walls can be detected without resort to costly drilling. Airborne surveys carried on extensively in half a dozen western States have revealed substantial new uranium sources. Instruments fitted in high-powered light planes record radioactivity as airmen sometimes skim within 15 to 20 feet of canyon walls. Ground parties are dispatched to areas showing worth-while deposits. - A flying prospector darts under Arizona's Navajo Bridge, 467 feet above the Colorado River.