Elmissikat-Eleridiya district is one of the most important uranium localities in the central Eastern Desert of Egypt. The feature oriented principal component selection (FPCS) and spectral angle mapper (SAM) techniques were applied on ASTER L1B imagery for mapping the common alteration zones. The study revealed that ASTER VNIR-SWIR bands are effectively used for delineating sericite, kaolinite, chlorite, illite and hematite bearing alteration zones, whereas ASTER TIR bands are most effective in delineation of silica-rich zones, which associate and could be used as pathfinder for radioactive mineralization within the study area. The resultant alteration maps show good coincidence with the explored uranium sites and suggest further similar unexplored sites. The results could assist the development of uranium exploration in the study area and other similar localities within the Egyptian deserts.
Maximum Likelihood (MLH) supervised classification of atmospherically corrected Landsat 8 imagery was applied successfully for delineating main geologic units with a good accuracy (about 90%) according to reliable ground truth areas, which reflected the ability of remote sensing data in mapping poorly-accessed and remote regions such as playa (Sabkha) environs, subdued topography and sand dunes. Ground gamma-ray spectrometric survey was to delineate radioactive anomalies within Quaternary sediments at Wadi Diit. The mean absorbed dose rate (D), annual effective dose equivalent (AEDE) and external hazard index (Hex) were found to be within the average worldwide ranges. Therefore, Wadi Diit environment is said to be radiological hazard safe except at the black-sand lens whose absorbed dose rate of 100.77 nGy/h exceeds the world average. So, the inhabitants will receive a relatively high radioactive dose generated mainly by monazite and zircon minerals from black-sand lens.
Seven fungal species were isolated from two uranium ores in Alloga region, west central Sinai, Egypt. They were identified as, Aspergillus flavus, Penicillium brevicompactum, P. oxalicum, P. purpurescens, P. lividum, Aspergillus terreus and P. spinulosum. They were tested for bioleaching activity of uranium from its ores, A. terrus and P. spinulosum showed a high leaching activity. The growth of these fungi highly affected by the presence of the ore in the growth media. The amount of uranium solubilized by A. terreus and P. spinulosum was increased with increasing ore concentrations in the growth media, reaching its maximum at 4%(w/v). Whereas, the highest percentage of uranium released by both fungi was obtained at 1%(w/v), at this concentration the released uranium being 75 and 81.5% respectively for ore (OS1) and 72.8 and 77.6% respectively for the second ore (OS2). The best leaching occurs when the final pH shifts toward acidity. The biosorption of released uranium by the fungal mycelium was also increased with increasing ore concentrations in the growth media. One gram dry mycelium of A. terreus and P. spinulosum could bind approximately 9.6 and 14.2% respectively, at 1% of OS1 and 10.8 and 17% respectively, at the same concentration of OS2 from the total uranium solubilized during bioleaching process.
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