The environmental impact of the uranium industry: is the waste rock a significant contributor?

Over the first five years of operation of the Brazilian uranium open mine and mill facilities, a study was carried out in order to assess the influence of the different sources on the increase of 226Ra and 238U surface water concentrations and to the dose commitment to the critical group. The highest contribution was found to be from the waste rock because of its availability for leaching processes, facilitated by the pyrite content of the rock and the high rainfall in the region. The ready leaching of radionuclides from the ores by rainwater calls attention to the fact that even during prospecting, increases of 226Ra and 238U in the environment can occur. One can conclude from this study that whenever a high rainfall occurs together with a high pyrite content, mining as a whole is the most important activity of the uranium industry as far as doses to members of the public are concerned. (author)