Aerial measurements on uranium ore mining, milling and processing areas in Germany

Abstract The paper describes aerial measurements at several sites containing residues from uranium mines, waste rock dumps and tailings ponds of the Wismut company in Saxony and Thuringia. For the measurements, a computerized gamma-ray spectrometer equipped with a HPGe-detector and a NaI(Tl)-detector array with a volume of 12 l was used. Radioactive anomalies from natural radionuclides have been detected and mapped. The activity concentrations of 226 Ra, 228 Th and 40 K in areas with elevated radioactivity from natural radionuclides were determined from aerial measurements. Ground-based measurements — as far as available — confirmed these results. The mean 226 Ra activity concentrations in the different waste rock dumps were found to be in the range 370 to 1600 Bq kg −1 . The highest mean 226 Ra activity concentrations were measured for the tailings ponds with values up to 1300 Bq kg −1 . For 40 K and 208 Tl, activity concentrations of 860 and 40 Bq kg −1 , respectively, were obtained as averages of all measurements. These values are commonly found in the environment. In general, there is reasonable agreement between the results measured with different detectors and measuring methods.