الفهرس 
General Statements
Geologic Setting and Petrographical StudiesOnly 14 pages are availabe for public view
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Abstract
The present work focuses on the geological, mineralogical, radiometrical, geochemical and leaching characteristics of the stream sediments of Wadi El-Reddah.
Wadi El-Reddah is mainly trending N-S and filled with stream sediments. The main outcrops in the study area are diorites, Hammamat sedimentary rocks, monzogranite, alkali feldspar granites, post-granite dykes and stream sediments.
The studied sediments show variation between chemically and radiometrically measured uranium (Uc/Ur) reach up to 22.7 ppm, suggesting recent uranium mineralization. Based on these analyses, uranium deposits in the studied stream sediments could be classified into:
1- old uranium deposits and 2- young uranium deposits.
eTh/eU and eU/eTh ratio values confirm the presence of near uranium mineralization. It is worthy to mention that there is uniform increasing in uranium concentration in all directions of Wadi El-Reddah and decreases in the central part, uniform vertical distribution of uranium to one meter depth and may become different with depth.
The low 234U/238U ARs in the studied stream sediments could be resulted from the addition of uranium from the surrrounding anomalous Gattar granites with a high uranium concentration as dissolved uranium. The activity ratios of 234U/ 238U, 230Th/ 234U and 226Ra/ 230Th for the studied sediments show obvious deviations from secular equilibrium, indicating the presence of water–rock interactions during the last 1 Ma and probably longer.The mineralogical study revealed that the main mineral associations in the studied stream sediments of Wadi El-Reddah are represented by uranium – thorium and REE-bearing minerals (thorite, uranothorite, zircon, xenotime and monazite), REE-bearing minerals (cerianite), Nb-Ta minerals (columbite, ferrocolumbite and yttro-columbite) and base metals include (pyrite, chalcopyrite, arsenopyrite and sphalerite), in addition to apatite, titanite, casssiterite, epidote, garnet and iron oxides. Low temperature alterations of thorite, zircon and xenotime were recognized as a result of the presence of calcite, fluorite, biogenic sulphides, sulpher-bearing minerals in these streams which play significant role in the change of pH and Eh of the medium and enhance the alteration processes. Invisible gold often associates sulphide minerals (chalcopyrite), as indicated by EDAX and Fire-assay analyses.
Geochemically, most stream sediment samples exhibit increase in SiO2, Fe2O3t, Na2O, P2O5 and K2O and L.O.I., a prominent decrease in Al2O3, TiO2, MnO, MgO, and CaO. However, trace elements show enrichment in Ni, Cu, Pb, Zn, Cd, Ta, Nb, Zr, Y, Rb, Cs, Ga, Hf, Sn, Th, Tl, U, W, Mo, Bi, As, Be, Li, Sb and Au, whereas they are depleted in Co, Sr, V, Ag, Cr and Sc. Their REE patterns are well characterized by the M- and W-type tetrad effects.
With respect to hard rocks, loss and gain calculations indicate that the altered samples, generally, exhibit an increase in total iron, K, Mn, Al, Ca and Mg and decrease in Na, P, Si, L.O.I. and Ti, in addition to the elevated Cu, Co, Pb, Cs, Y, Ga, Hf, Sn, V, Nb, Rb, Ta, Th, U, Tl, Zr, W, Zn and the depleted Ba, Sr and Ni contents. Y/Ho ratios values show the complexation with fluorine and carbonates which is confirmed by the presence of fluorite and calcite.The optimum conditions for leaching experiments of the stream sediment at Wadi El-Reddah were found to give maximum uranium extraction at 160°C with ore grind size of -150μ passing through 60 mesh maintained at leaching agent 5M sulphuric acid with solid/ liquid ratio 1:5. After leaching experiment, purification experiments using ion exchange resins followed by precipitation to obtain final product, yellow cake U3O8. Other products like Th, REE and Ni were also precipitated from stream sediments. As a result of purification by ion exchange, a precipitate contains also Ag, Cu, Co, Ni and Zn.