Application of Soil Radon and Trace Element Geochemistry for Uranium Exploration at Kuchanapalle, Guntur District, Andhra Pradesh

A radioactive fault breccia zone trending N30°E is exposed intermittently within the puru granite dome, near Kuchanapalle village in the NE margin of Cuddapah basin. A major part of the fault zone is under soil cover. Within this fault zone, a dark coloured ferruginous and uraniferous fault breccia is exposed over an area of 150m x 2.5m. In order to trace the continuity of the concealed fault zone, the uraniferous breccia zone was tested by closed circuit soil-gas radon (CCT) measurement, solid state nuclear track detection (SSNTD) survey, and trace element analysis of augur-hole soil samples. Radon levels in 164 auger holes vary from 9 to 863 per 50 sec. The alpha track density on cellulose nitrate films used in SSNTD surveys varies from 27 to 820 per sq. mm. The iso-alpha track density map has confirmed the anomalous patterns obtained by the soil-radon survey.

Trace element data of soil samples have been processed using R-mode factor analysis of correlation matrix. These data along with radon and SSNTD surveys have thus been found to be very effective in delineating the extension of the radioactive breccia zone under soil cover, up to 1200 m towards north.