[en] Radioactive sand stone samples of sedimentary rocks constitute fine particles like clays, hydrous iron oxides (goethite) and humic acid. All these colloidal particles have the property of sorption, ion-exchange etc. under suitable conditions. Hence the ability of these fine particles for uranium sorption and retention has been investigated in detail individually on ferric hydroxide gel, goethite and humic acid gel and the thermoanalytical studies were also carried out. Freshly precipitated ferric hydroxide gel exhibited uranyl sorption upto 9%. Natural and synthetic goethite showed upto 2.8%, and humic acid upto 6% under optimum conditions of pH and uranyl concentration. Differential thermal analysis was carried out to characterise ferric hydroxide gel, natural and synthetic goethite and humic acid gel. (author)

[en] The present study has indicated two mineralizing events. The 1.6 Ga age based on both U-Pb and Sm-Nd studies on samples from Banadungri-Singridungri can be taken as a primary mineralization event. The 1.0 to 1.1 Ga ages obtained from mineralized conglomerates and schistose rocks from Jaduguda could be due to later remobilization. This younger event also coincides with the latest tectonomagmatic/hydrothermal event recorded in the SSZ. The present study has indicated two distinct mineralizing events, viz. 1.6Ga at Banadungri-Singridungri, and 1.0-1.1Ga at Jaduguda. It is a well-established fact that subsequent remobilization in several phases along Singhbhum Shear Zone has resulted in the formation of different generations of uranium phases in each deposit. The present data indicates that contribution from the remobilized uranium phases is much higher in Jaduguda deposit in comparison to Banadungri-Singridungri area