[en] Factor analysis of multi-element data for Dhanjori conglomerates of Singhbhum district, Bihar, in eastern India reveals three factors accounting for about 57% of the total information contained in the data. Factors 1 and 2 are associated with radioactive elements. They also indicate that the provenance is a mixed felsic and mafic terrain, and that the minor and accessory constituents of these rocks are concentrated in the conglomerates. These two factors appear to result from the same sedimentological process. The factor-3 results from the V-Al diadochy. Factor-1 which is seen to be associated with both zircon and radioelements does not contain Pb. Pb is relegated to the factor-2. (author)

[en] A simple and economical method for the removal of uranium from Gogi mine water using the powdered red brick as a good adsorbent is discussed. Preliminary studies for the removal of uranium using brick showed encouraging results. Further studies were carried to find the amount and size of brick for the quantitative removal of uranium. The results of these studies showed that 50 g of brick with 10 mesh size was enough to remove uranium quantitatively from 100 ml of mine water containing 1800 μg/L of uranium. However the column studies indicated considerable decrease (∼ 5 g for 100 ml of mine water) in the amount of brick required to remove uranium from 100 ml of mine water

[en] Gogi uranium deposit is located in an intensely fractured, tectonised and structurally complex sectors of the E-W trending Gogi-Kurlagere fault in the central-peripheral part of the Meso-Neoproterozoic Bhima basin. Ore lodes are mainly hosted in the brecciated impure limestone and basement granite-cataclasite-mylonite which are concealed under a thick column of soil. The deposit is flanked by two natural shallow water bodies and the water table locally fluctuates from surface level to a depth of ∼ 2m. Prevailing conditions result in to the constant interaction of ground water with dipping ore zone which continues over a strike length of ∼ 1.5km having a plan width of ∼ 200m and extending up to 220m below the surface

[en] Granite core samples (n=14) from the Gogi-Kurlagere fault zone in the central part of the Bhima basin were studied in terms of LREE, Y and Zr mobility during uranium mineralization. LREE, Zr and Y along with LILE (Ba, Rb) and P show behavioral differences in the mineralised and the non-mineralised samples. Average ΣLREE in mineralised granite (240 ppm) is higher than in non-mineralised samples (157 ppm). The average Zr and Y in the mineralised granite are 193 ppm and 17 ppm, while the corresponding abundances of these elements in non-mineralised portion are 148 ppm and 11 ppm respectively. Besides enrichment of U, Th, Ba, Pb and Rb and depletion of Sr are observed in mineralized granite in comparison to non-mineralized granite. Hydrothermal alteration has led to the mobility of these elements, which are again dependent on the overall geochemical behavior of the migrating fluid. REE and Y in association with uranyl ((UO_2)"2"+) ion were transported as carbonate complexes like (UO_2(CO_3)_3)"4"- and (REE (CO_3)_3)"3"- and were later incorporated into favourable structural loci by precipitating minerals like pitchblende and coffinite. (author)

[en] The granitoids represented by zircon-granite, porphyritic alkaline granite, riebeckite granite, adamallite and syenite around the Kumarkunti-Jharnomal area, occur in a linear N-S trend along the eastern faulted contact of the Khariar-Nuapara outlier. The major element chemistry shows a rising trend in SiO₂, Al₂O₃, Na₂O, while a falling trend is noted in case of MgO and FeO with respect to differentiation index. They are metaluminous to peraluminous in nature with A/CNK values ranging from 0.31 to 2.68 (av. 1.65). The agpaitic index (mol Na₂O+K₂O/Al₂O₃) is <1 (0.30 to 0.34) indicating its sub alkaline nature. Geochemical study of the granitoids indicates anomalous concentration of the elements like Y (120-1231 ppm), Nb (72-7350 ppm), Ta (86-526 ppm), La (129-1757 ppm), Ce (453-1876 ppm), Sn (15-273 ppm), U (42-262 ppm), Th (0.1-4%), Zr (0.4-6.2%) along with Rb (179-553 ppm). The petromineralogical studies indicate that the anomalous concentration of trace elements is mainly due to the presence of thorite, allanite, fersmite and zircon. Geochemical signatures such as Ga 9 to 58 ppm, very high ratios of Rb/Sr, Fe₂O₃/FeO and strong depletion in Ba and Sr, along with a rather low Ca and Mg, point to its A-type character. Various discrimination diagrams reveal the origin or these granites under within plate tectonic setting. (author)

[en] A re-appraisal of major uranium deposits/occurrences related to Proterozoic basins of Dharwar Craton is attempted to evaluate possible exploration strategies for diverse nature of Uranium mineralizing events. Dharwar Craton consists of an older (~3.0Ga) Na-rich Western Dharwar Craton and a younger (~2.5Ga) K-rich Eastern Dharwar Craton. Proterozoic basins viz., Cuddapah and Bhima are exclusively evolved on the basement of Eastern Dharwar Craton, besides the eastern parts of Kaladgi, and contain different types of uranium mineralization such as large tonnage stratabound carbonate hosted type in Tummalapalle and surroundings (SW parts of Cuddapah basin), unconformity type in Lambapur-Peddagattu-Chitrial (northern parts of Cuddapah basin), hydrothermal fracture controlled mineralization at Gogi (Bhima basin) and unconformity proximal fracture controlled mineralization at Deshnur (Kaladgi basin). Exploration models for carbonate hosted uranium mineralization are based on the strength of the source feeding to the basin which may not be similar all along the basin margin having very long geographical extension. Likewise, significance of basement fractures extending beneath the cover rocks in NE parts of Cuddapah basin has important bearing in formulating exploration schemes. In Bhima basin, besides other factors, the components like major reverse faults affected by later cross faults are vital in deciding the target areas. The palaeo-lows and fractures affecting both the basement and sediments are important criteria to build exploration models in Kaladgi basin to target Deshnur type of mineralization in Badami Group of rocks in Kaladgi basin. Lower parts of Kaladgi basin hosting stromatolitic dolomites developed on DC may be targeted for carbonate hosted uranium mineralisation as in Tummalapalle, Cuddapah basin. (author)