Aerial Detection of Radioactive Mineral Deposits
A resumé of aerial radiation survey studies performed by and for Eldorado Mining and Refining, Limited, since 1943 is presented. Flight tests were initiated in 1947 and were followed .by intensified use and study of Geiger counters and other radiation detectors. Development of an aerial scintillation counter ibeg.an in 1948, but a sensitive large crystal unit was not available for exploration purposes until 1950. Modifications of this unit have been used in all subsequent surveys. For the Eldor111do detector several limiting conditions were established for successful radioactivity detection, the most important being that natural vein exposures can only be assuredly detected .at distances Jess than 150 feet. Sedimentary and Pegmatitic radioactive occurrences can be detected at much greater distances. A helicopter investigation technique appears to have a useful prospecting potential.