Uranium prospecting in northeastern Goiás state, Brazil: Multiple regression applied to airborne geophysical data

Abstract

Nuclebrás and Comissão Nacional de Energia Nuclear (CNEN) investigated northeastern Goiás State, Brazil, in the 1970s and 1980s to detect radioactive elements, when the Rio Preto and Campos Belos prospective uranium projects were undertaken. These projects identified an estimated 1,000 tons of U3O8, which was considered small and, therefore, search was interrupted in these areas. In 2006, an airborne geophysical survey covered these areas with gamma ray spectrometry and magnetometry data. Aerogeophysical data has been widely used in the direct detection of uranium mineralized bodies. However, in areas of great lithological variability, the determination of the anomalous values becomes difficult because uranium concentration is significantly influenced by the rock type. The objective of this study is to evaluate the multiple linear regression technique applied to the aerogeophysical data that cover the anomalous lithological units of uranium in northeastern Goiás, using the methodology proposed by Pires et al. (2010), to mitigate the influence of lithology on the uranium concentrations. The results demonstrate the effectiveness of the proposed methodology for the removal of lithological influences on the uranium levels, highlighted the known uranium occurrences in the region and identified new prospective targets for this radioelement.