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In this study, the mobility of natural uranium in fractured granite was investigated by focusing on the roles of uranyl silicate minerals formed by long-term interactions with oxic groundwater. Uranium-bearing minerals observed in granite samples were identified as uranyl silicate minerals (i.e., uranophane, haiweeite, and soddyite) and this result was supported by uranium speciation calculation. The uranyl silicate minerals play important roles in understanding the mobility of uranium and the effects of water–rock interactions on long-term behavior of uranium in fractured granite systems.

Hydrometallurgical processing of micaceous bands concentrate for recovering U and Th using sulfuric acid agitation leaching was studied. This concentrate assays 4.1% ZrO2, 3.8% Nb2O5, 1.2% RE2O3, 2.8% ThO2, and 0.55% U3O8. The corresponding minerals of these elements include zircon, ferrocolumbite, fergusonite, uranothorite, autunite, and uranophane. About 96% of Th and 94% of U were dissolved under optimum leaching conditions: 30% H2SO4, 1/3 S/L ratio, 4 h leaching time, and 85°C leaching temperature. Di(2-ethylhexyl) hydrogen phosphate (HDEHP) in kerosene was used for U extraction with 90.9% efficiency and its separation from Th in the presence of 0.3 M EDTA solution. Th was then selectively precipitated from the raffinate solution as Th peroxide.

The present work deals with the detailed geology, mineralogy, geochemistry, and spectrometric prospection of the felsic volcanic rocks at the Eastern Desert, Egypt of the Arabian-Nubian Shield. Felsic volcanic rocks are an essential source for rare earth elements (REEs) and uranium occurrences in this area. They are compositionally uniform with tholeiitic to calc-alkaline affinities, peraluminous and belong to the series of rhyolite with high-K melt. They exhibit more enrichment in high field strength elements (HFSE, e.g. Zr, Ta, Nd, Th, and U) and large-ion lithophile elements (LILE, e.g. Pb and Rb) compared to the country rocks of the studied area, with REE ranging from 188.20 to 442.70 ppm and strong depletion in Ti, Sr, P with deep negative Eu oddities. The felsic volcanic rocks were mostly generated from the partial melting of quartz-amphibolite facies accreted during the Neoproterozoic. Positive oddities of Zr- U- Th for the felsic volcanic rocks determine the involvement of crustal materials. Felsic volcanic rocks are found in A-type suites of magma and represent highly fractionated rocks derived from rhyolitic magma, with insignificant interaction with continental crust in the low-pressure environment and during fractional crystallization. Felsic volcanic rocks have higher values of radioactivity in which eU range from 0.5 to 121 ppm and eTh from 1.0 to 415.10 ppm. The high values of eU and eTh can be ascribed to the mineralization of uranium and the presence of accessory minerals of radiogenic nature such as uranophane, uranothorite, zircon, and monazite. Uranophane is considered as the mineral with most enriched uranium contents in the studied felsic volcanic rocks in which (UO2 = 87.30 wt %). Also, they are enriched with REE-bearing accessory minerals comprising allanite, titanite, and apatite. The geological investigations of the felsic volcanic rocks in the studied areas are inappropriate to clear the feasible economic potentialities of rare earth elements and U occurrences; itemized and invaluable explorational work is as yet needed. Whilst, the environmental impact of mineralization, owing to U and Th and their radiogenic daughter products, is observed and must be elaborated minutely.

The present work deals with the mineralogy, geochemical behavior and uranium potentiality of the monzogranites of El Maghrbia area, which comprise G. El Maghrbia and G. El Eredyia and situated in the central Eastern Desert of Egypt. G. El-Erediya monzogranites represents a promising area for uranium mineralizations. These granites have shear zone filled with red and black silica veins containing many radioactive anomalies with visible yellow secondary uranium minerals. The shear zone is highly affected by different degrees of alterations such as silicification, kaolinitization, sassuritization and ferrugination. Monzogranites of El-Erediya area possess higher values of their radioactivity than in El Maghrbia monzogranites in which eU and eTh, reaches up to 792.3 and 66.81 ppm, whilst average content of eU and eTh in El Maghrabia granites are 3.86 and 8.55 ppm, respectively owing to the presence of radioactive minerals such as uraninite, uranothorite, uranophane, kasolite, betafite, zircon and monazite. Intensive geochemical analyses indicated that, the studied monzogranites are distinctly anomalous in U, where the average U is more than 620-fold the Upper Continental Crust (UCC), marked enrichment (> tenfold) of the elements Cd, Mo, Pb, Bi, Nb and W. The Th/U ratio decreases from 2.8, as a chondritic value, to 0.0023 for the studied granites, proposing extreme fractionation towards an extensive secondary migration-in of U. The Zr and Hf are depleted in the studied granites relative to the UCC, whereas Nb and Ta are strongly enriched. The content of Y is about sixfold enriched which reflects relative enhancement of the HREE during the alteration processes. Uranium correlates with Fe2O 3 T , suggesting a possible association between uranium and ferrugination. Thus, the occurrences of uranium are epigenetic by remobilization from the host rock to the sheared zones, probably through metasomatic process where U–Fe–Mg replaced the feldspars in an oxidized condition. The high levels of radioactivity in the rocks being studied it them a priority for discovery and expanding the potentiality of the highly mineralized localities.

G. El Sela is located in the Southern Eastern Desert of Egypt cropping as two parts, occupied by monzogranites that were categorized as biotite granite, muscovite granite and two mica granites. The northern part is more significant according its high concentrations of uranium that controlled by complicated structure regime; faulting, infrastructures and shearing are the most common structural criteria of this part. The Egyptian Nuclear Materials Authority (NMA) mined this part to produce the uranium ore. The previous mineralogical studies indicated that this granite was dominated by primary uranium minerals (pitchblende and coffinite) and secondary minerals belong to the autunite group (autunite, metautunite, phurcalite) in addition to uranophane. In the present work, petrographic and mineralogical studies are applied for the granites using the polarized and stereo microscopes and followed by electron microscope and XRD. The result of the microscopic examinations revealed the tectonic regime controlling the radioactivity and recognized the sodic autunite (meta-natroautunite) beside the pre-mentioned autunite group minerals completing the paragenetic sequrnce of these minerals. In this study, it is concluded that the sheared biotite granite is monzogranite originated during the episode of the continental plate collision (syncollision). The study finished to presence of two main types of the alteration corresponding to the two high levels of radioactivity (moderate and anomalous). The first is the thermal alteration (saussiritization, sericitization, kaolinization, silicification and hematization) and the second is the chemical transformation (oxidation, dehydration, ion substitutions and confusion) responsible for formation of the secondary uranium minerals. The temperature needed for the thermal alteration is sourced by the hydrothermal solutions, while the temperature needed for the uranium minerals transformation may be generated during the episode of the continental plate collision (syncollision). Paragenesis of these minerals indicates that they represent a series of uranyl phosphate minerals (autunite group) with paragenetic sequence starting by autunite (calcic uranyl phosphate) and ends by meta-natroautunite (sodic uranyl phosphate). An advanced process of dehydration accompanies the process of mineral transformation from autunite to meta-natroautunite leading to formation of the anhydrous uranyl mineral (phurcalite) formed by oxidation and dehydration of autunite. Meta-autunite is recorded as a transitional mineral composed of sodic-calcic uranyl phosphate. Uranophane is created by thermal confusion of autunite with the silica.

International audience; Uranium (U) deposits can undergo oxidizing events, subsequent to which the U may be redistributed or precipitated under distinct mineralogical forms. Occurrences of U6+ minerals can be the result of either (i) in situ oxidation and alteration of previous U4+ minerals or (ii) direct precipitation from U6+-rich solutions. Samples from Imouraren, the largest U6+ore deposit known in the world, located in the Tim Mersoï Basin, Northern Niger, have been studied to determine the nature, distribution, and timing of occurrences of U and related minerals. The host rock is composed of sandstones and analcime-rich siliciclastic rocks of Jurassic age. The U ore is largely dominated by acicular hexavalent U minerals and by a very small amount of uraninite. A comprehensive geochemical model that describes the origin and geochemical setting of this style of economically important mineralization has been developed. The petrographic and mineralogical studies show evidence of in situ uraninite alteration into uranophane and metatyuyamunite, documented by textural relationships and chemical analyses using SEM and electron microprobe. The textural relationship between the U4+ and U6+ minerals is supported by the near-identical REE signatures of the primary uraninite and related secondary U minerals. Ion microprobe U-Pb dating (from 21 to ~ 1 Ma) confirms that primary uraninites were altered to U6+ minerals under supergene conditions during Cenozoic oxidation events in western Africa, in relation with the well-known stages of intense continental weathering that have affected western Africa from the early Cenozoic to recent times.

The NNW-SSE trending leucogranites in and around Mastipuram, Wanaparthi district, Telangana are intrusive into Peninsular Gneissic complex. The leucogranite is metaluminous to mildly peraluminous, alkali-feldspar granite with I-type signatures, probably formed from a fractionated melt involving crustal component. Magmatic and hydrothermal contributions are supported by wide range of U/Th ratios in mineralized samples, which also show Na-enrichment as compared to non-mineralized leucogranites. Average U and Th contents and U/Th ratio in mineralized leucogranite is 541ppm, 147 ppm and 2.85, respectively. Main ore mineral is uraninite and its altered form - gummite, while secondary uranium minerals such as schoepite, uranophane and haiweeite are also identified in leucogranite by XRD. Reconnoitory drilling of ten boreholes have confirmed sub-surface continuation of uranium mineralization with varying width of 1m to 31m at vertical depth of about 50m. Thus, the leucogranites bordering Gadwal schist belt around Mastipuram forms a very potential target.

Gabal Shendib alkaline ring complex forms high positive topographic rock units of concentric circularoutcrop. The igneous complex has a diameter of 12 km emplaced within the metavolcanics and tonalitegranodioritehost rocks. The complex consists of olivine gabbro, alkaline granite, alkaline syenite and remnants of the volcanic rocks represented by porphyritic trachyte, porphyritic rhyolite, rhyolite and tuffs. These alkaline rocks show a strong enrichment in some rare metal contents (Zr = 4527, Nb = 717, Y = 806 ppm) and rare earth elements (La = 553, Ce = 1581, Pr = 214, Nd = 1145, Sm = 299, Gd = 55, Dy= 85ppm). The highest Rb/Sr ratio and lower Ba/Rb ratio of the studied alkaline rocks of Gabal Shendib ring complex indicating a high degree of fractionation of the melt associated with mineralization.REE abundance patterns of the alkaline granite and alkaline syenite display M-type and W-type tetradeffect with strong Eu depletion in both whole rock samples. Fluid-melt interaction in the late stage offractional crystallization is suggested to be the most important factor controlling the formation of REEtetrad effects in these alkaline rocks. The most important REE-bearing minerals are zircon, xenotime,monazite, allanite and apatite. Other accessory minerals include columbite, uranophane, urnothorite andtitanite are identified.Field radiometric measurements and chemical analysis for uranium content of the alkaline granite and alkaline syenite revealed low uranium content. Radioactivity level reaches up to 13.70 ppm eU in alkalinegranite and 4.90 ppm eU in the alkaline syenite. Chemical analysis of uranium revealed that U contentreaches up to 35 ppm in the alkaline granite and 15 ppm in the alkaline syenite.

U-Pb isotope systems have been used to constrain the timing of formation, alteration, and oxidation of U minerals from the meta-granitic bedrock at Forsmark, eastern Sweden. Secondary ion mass spectrometry (SIMS) has been used to collect U-Pb data from uraninite. Discordant data suggest a ~1.8 Ga emplacement of uraninite-bearing pegmatites and an event of uraninite alteration at ~1.6 Ga. The latter age is contemporaneous with the Gothian orogeny in Scandinavia, which was associated with hydrothermal fluid circulation in the Fennoscandian Shield. Ca-uranyl silicates haiweeite and uranophane predominately formed 1.3–1.2 Ga, contemporaneous with the emplacement of the Satakunta complex of the Central Scandinavian Dolerite Group. A Palaeozoic group of Ca-U(VI)-silicates is also present, which indicates that the geochemical composition of geologic fluids was heterogeneous throughout the fracture network during this time. Low Pb concentrations in the U(VI) silicates of several samples are compatible with a recent (

Kaolinitization, ferrugination, silicification, and illitization hematitization are the main alteration types recorded in the Gabal (G.) El Sela area, South Eastern Desert, Egypt. These altration zones occur in successive manar as supergene events along faults plane causing mineral redistribution. Uranium mineralization observed in the northern part of Gabal El Sela is mainly controlled by complicated structure regime: faulting, infrastructures, and shearing. So, the northern part of Gabal El Sela area is considered as the most significant and U-fertile part in the studied area. Visible secondary uranium minerals (uranophane and autunite) have been identified and are found to be related mainly to kaolinitized and ferruginated altered samples. Also, pyrite and chalcopyrite can be recorded as reduced Fe bearing minerals in fewer amounts than in hematite and goethite minerals. Finally, the present work confirms that G. El Sela granite is considered as one of the most promising granite plutons in Egypt. The fertility parts are mostly related to the extent of the overlap between the magmatic uranium enrichment, hydrothermal reworking through open fracture system, and suitable reservoir for the leached mineral. The U mineralization may be the result of all these reactions between the granite and the successive fluids.

Long-term uranium mobility in tailings is an environmental management issue. The present study focuses on two U-enriched layers, surficial and buried 14.5 m, of the tailings pile of Cominak, Niger. The acidic and oxidizing conditions of the tailings pile combined with evapotranspiration cycles related to the Sahelian climate control U speciation. Uraninite, brannerite, and moluranite as well as uranophane are relict U phases. EXAFS spectroscopy, HR-XRD, and SEM/WDS highlight the major role of uranyl sulfate groups in uranium speciation. Uranyl phosphate neoformation in the buried layer (paleolayer) acts as an efficient trap for uranium.

In this work, the probable sites of the radioactive mineralization in the younger granite of the Um Bogma area was mapped, prospected and detected by using geospatial technology. Our approach combined diverse data that have a close relationship with radioactive mineralization. These data are lithological, hydrothermal alteration minerals and airborne data. To achieve the aim of this work, the geospatial technology was used. Two techniques band ratio and Feature Oriented Principal Component Analysis (Crosta technique) were applied on ASTER satellite images to distinguish lithology and minerals indicative of hydrothermal alteration. Estimated weights were assigned to the lithology, alteration minerals and airborne data based on statistical methods. All these weighted data integrated to produce the predictive control models that related to mineralization using GIS applications. Three potential sites for radioactive mineralization were identified from the predictive control model. These potential sites were validated via fieldwork surveillance from these sites. Both of fieldwork and laboratory examinations confirm the association of these potential sites with the altered younger granite where uranophane and other minerals are recorded.

The main rock types exposed at Wadi Ras Abda area are subduction-related older granite intruded by fine-grained alkali feldspar granite (microgranite intrusions). These rock types are dissected by acidic dykes (rhyolite) and basic dykes (basalt and dolerite) with their associated pegmatites and quartz veins. Ras Abda microgranite is highly radioactive and this radioactivity is structurally related. The thorium, uranium, and rare metal mineralization are distinguished within the microgranite intrusions along fault zones that are trending N40° E with high dipping angle reaching to 86°. It shows radioactive measurements ranging from 500 to 9500 ppm and showing visible secondary uranium and thorium minerals in addition to the deposition of black rare metal minerals. Uranothorite, thorite, and secondary uranium minerals (uranophane) are the main radioactive minerals at Wadi Ras Abda area, in addition to the rare earth–bearing mineral (REE) fergusonite. Six events are affected in W. Ras Abda area. Each event begins with compression (CP) and then extensional (EXT) phase of deformation. These events were arranged chronologically basing on field relations from the oldest to the youngest as following: WNW-ESE (CP), NNE-SSW (EXT), E-W (CP), N-S (EXT), NE-SW (CP), NW-SE (EXT), NNE-SSW to N-S (CP), WNW-ESE to E-W (EXT), NW-SE to NNW-SSE (CP), ENE-WSW to NE-SW (EXT) and ENE-WSW (CP), and NNW-SSE (EXT). The WNW-ESE to E-W–directed tensile stress reactivated faults and induced new faults along which the mineralized fluids flow. It is recognized that the low-stress regions in the vicinity of faults and their associated tension joints, along contacts between microgranite and older granite, are favorable locations for alterations and Th-U and REE mineralization.

The shear zone of the El-Missikat area is considered one of the most important occurrences of uranium (U) mineralization in the Central Eastern Desert of Egypt. This shear zone is characterized by a tabular elongated zone of crushing and brecciation resulting from many parallel fractures or intense jointing, and presence of silicification and other alteration products together with the occasional presence of U mineralization. The concentrations of the natural radionuclides were measured by Sodium Iodide Detector NaI (Tl) in 87 granitic rocks and silica veins collected from the Central Eastern Desert. Measurement of radioactive elements suggests U present in granite of the El-Missikat pluton as well as in red, black and jasperoid silica veins. Radioactive mineralization was determined by scanning electron, binocular, and polarizing microscopies. The mineralizations are represented by syn-genetic U-leaching origin accompanying granitic rocks and post-magmatic association in red and black silica veins. The U-host mineralizations are mainly represented by radioactive minerals such as uranophane, kasolite, and U-bearing zircon.

Three new materials related to the phosphuranylite family were synthesized by using alkali chloride fluxes at 875 °C: CsNa3[(UO2)3O2(PO4)2] (1), Cs2Na4[(UO2)5O5(PO4)2] (2), and Rb6[(UO2)5O5(PO4)2] (3). CsNa3[(UO2)3O2(PO4)2] (1) crystallizes in the triclinic space group P1 with the lattice parameters, a = 6.9809(3) A, b = 9.3326(4) A, c = 12.9626(5) A, α = 71.5620(10)°, β = 78.9430(10)°, and γ = 68.0840(1)°; Cs2Na4[(UO2)5O5(PO4)2] (2) crystallizes in the triclinic space group P1 with the lattice parameters, a = 6.9890(3) A, b = 12.9652(6) A, c = 13.2086(6) A, α = 96.224(2)°, β = 101.433(2)°, and γ = 105.459(2)°; and Rb6(PO4)2[(UO2)5O5] crystallizes in the P21/m space group with the lattice parameters, a = 6.9255(3) A, b = 24.773(1) A, c = 7.07647(3) A, and β = 90.741(1)°. The sheets of 1 are based on the phosphuranylite topology, while the sheets of 2 and 3 contain sheets based on the U3O8 and uranophane topologies but differ in the orientation of the phosphate tetrahedra. The regions between the sheets ...

The layered uranyl silicate clay-like mineral, uranophane-α, Ca(UO2)2(SiO3OH)2·5H2O, was studied by first-principles calculations based on the density functional theory method. The structure, observed in nature in a wide variety of compounds having the uranophane sheet anion topology, is confirmed here for the first time by means of rigorous theoretical solid-state calculations. The computed lattice parameters, bond lengths and bond angles were in very good agreement with the experimental ones, and the calculated X-ray powder trace accurately reproduced its experimental counterpart. The mechanical properties of uranophane-α, for which there are no experimental data for terms of comparison, were determined, and the satisfaction of the mechanical stability Born conditions of the structure was demonstrated by calculations of the elasticity tensor. The Raman spectrum was computed by the density functional perturbation theory and compared with the experimental spectrum. The vibrational properties of this mineral were well characterized, showing a good performance in all of the studied spectral range. Theoretical methods allowed assignment of the Raman bands to vibrations localized in different fragments within the crystal unit cell. Finally, the possibility of incorporation of strontium inside the uranophane structure was studied. The computed structure, X-ray powder trace and Raman spectrum of Sr-exchanged uranophane were very close to those of the ordinary Ca-uranophane.

Information-based parameters of structural complexity for two polymorphs of Ca[(UO 2 ) 2 (SiO 3 OH) 2 ] · 5H 2 O, uranophane and uranophane-β, were calculated in order to assess the impact of the structural complexity on their stability and formation. Calculations proved that uranophane-β is far more complex ( I G,total = 691.90 bits/cell) than uranophane ( I G,total = 345.95 bits/cell), which indirectly suggests that uranophane may form as a metastable phase during crystallization process. This suggestion is further supported by the lower density of uranophane (3.834 g/cm 3 ) compared to that of uranophane-β (3.983 g/cm 3 ). The hypothesis of a metastable character of uranophane is in agreement with Goldsmith’s simplexity principle and the Ostwald–Volmer rule and is well supported by the frequency of occurrences of both dimorphic minerals in Nature.

Heterogeneous equilibria in the system Ca(HSiUO6)2 · 5H2O(c)–aqueous solution were studied over broad ranges of pH, ionic strength, and ionic composition of the solution, and the pH range of stability of Ca uranyl silicate is determined. Hydrolysis products of Ca uranyl silicate are identified, and their solubility is determined. The equilibrium constant of the dissolution reaction and the standard Gibbs function of formation of Ca(HSiUO6)2 · 5H2O are calculated from experimental data, and solubility curves of uranophane and equilibrium speciation diagrams for U(VI), Si(IV), and Ca(II) in coexisting aqueous solutions and solid phases are calculated.

The southern part of the Eastern Desert of Egypt—about 30 km southwest of Abu-Ramad city—is mainly covered by ophiolitic rocks (Sul Hamed), island arc assemblage, younger granites (muscovite granites of Qash Amer and two mica granites of El Sela), and various acidic and basic dikes. Field, petrological, and geochemical studies indicate that the El Sela shear zone has been subject to hydrothermal and supergene alteration such as kaolinization, albitization, sericitization, and hematitization. It is invaded by quartz ENE–WSW veins associated with hydrothermal alteration accompanied by radioactive mineralization. The investigated younger granitic rocks had very low contents of compatible elements, such as Cr, Ni, and Co; and high contents of incompatible elements, such as Zr, and large ion lithophiles, such as Sr, especially in the El Sela shear zone. Major oxide and trace element analyses revealed calc-alkaline affinity and peraluminous character. These highly differentiated granitic rocks’ lower Zr/Hf and higher Y/Ho than the normal ratio are consistent with hydrothermal alteration. Most samples had rare earth element (REE)-patterns with an M-type tetrad effect in the first and fourth segments and a W-type tetrad in the third segment. The average ∑REE in the studied granites was lower than the world granite average; the ratio of light to heavy REEs greater. The main radioactive, uranium-bearing, and uraniferous Fe and Mn minerals are uranothorite, autunite, uranophane and autunite as compounds, kasolite, columbite, xenotime, uranophane-bearing zircon and jarosite, silver-bearing pyrite, hematite, and autunite-bearing pyrolusite.

The Younger Granites of Yahmid-Um Adawi area, located in the southeastern part of Sinai Peninsula, comprise two coeval Late Neoproterozoic post-collisional alkaline (hypersolvous alkali-feldspar granites; 608–580 Ma) and calc-alkaline (transsolvous monzo- and syenogranites; 635–590 Ma) suites. The calc-alkaline suite granitoids are magnesian and peraluminous to metaluminous, whereas the alkaline ones are magnesian to ferroan alkaline to slightly metaluminous. Both granitoid suites exhibit many of the typical geochemical features of A-type granites such as enrichment in Nb (>20 ppm), Zr (>250 ppm), Zn (>100 ppm) and Ce (>100 ppm) and high 10000*Ga/Al2O3 ratios (>2.6) and Zr + Nb + Y + Ce (>350 ppm). Accessory mineral saturation thermometers demonstrated former crystallization of apatite at high temperatures prior to zircon and monazite separation from the magma for both granitoid suites. The mild zircon saturation temperatures of the studied Younger Granites (around 800 °C) imply low-temperature crustal fusion and incomplete melting of the largely refractory zircon. The two Younger Granite suites were semi-synchronously evolved during the post-collisional stage of the Arabian-Nubian Shield subsequent to the collision between the juvenile shield crust and the older pre-Neoproterozoic continental blocks of west Gondwana. Their parental magmas has been generated by melting of crustal source rocks with minor involvement from mantle, which might participated chiefly as a source of heat necessary for fusion of the crustal precursor. Extensive in-situ gamma-ray spectrometry revealed anomalously high radioactivity of some Younger Granite exposures along Wadi Um Adawi (eU; 388–746 ppm and eTh; 1857–2527 ppm) and pegmatitic pockets pertaining to the calc-alkaline suite (equivalent U and Th; 212–252 ppm and 750–1757 ppm, respectively). The radioactivity of the syngenetic pegmatites arises from the primary radioactive minerals uranothorite and thorite together with the U- and/or Th-bearing minerals zircon, columbite, samarskite and monazite. The anomalously high radioactivity of some Younger Granite exposures in Wadi Um Adawi stem from their appreciable enclosure of the epigenetic uranium minerals metatorbenite and uranophane.

In this work, several individual grains of uranium minerals—uraninite with high content of Ca, Ca-rich boltwoodite, growths of uranophane with β-uranophane, and weeksite—from different uranium deposits were studied by a scanning nuclear microprobe. Particle-induced X-ray emission technique provided by the microprobe (µ-PIXE) was carried out to obtain a concentration and 2D distribution of elements in these minerals. In addition, energy dispersive X-ray spectrometry (SEM-EDS) provided by a scanning electron microscope was used. The types of minerals were determined by X-ray diffraction methods. Results of this study improved the understanding of trace elemental composition of the uranium minerals depending on their origin. Obtained signatures could be linked then to the sample provenance. Such data are important for nuclear forensics to identify the ore types and even specific ore bodies, when only small samples may be available for analysis. In this study, the µ-PIXE technique was used for obtaining the 2D distribution of trace elements that are not commonly measured by SEM-EDS at the relevant concentrations. The detected levels and precisions of elements determination by µ-PIXE were also defined. Using µ-PIXE, several micro mineral inclusions such as phosphate with high level of V and Si were identified. The age of the uranium minerals was estimated due to a significant content of radiogenic Pb that provides an additional parameter for determination of the main attributive characteristics of the minerals. This work also showed that due to its high elemental sensitivity the nuclear microprobe can be a new analytical tool for creating a nuclear forensic database from the known uranium deposits and a subsequent analysis of the intercepted illicit materials.

Sonrai basin, located along the southwestern margin of Bundelkhand Granite-Gneiss Complex (BGC) is known for its base metal and phosphorite mineralization. Uranium mineralization of appreciable grade and thickness was reported in Pisnari block in the northern part of this basin during sub-surface exploration activity in 1976-97. This was in the form of uranium-bitumin association within fractures in the carbonate-terrigenous sediments of Gorakalan shale, Rohini carbonate and Bandai sandstone of Sonrai Formation of Bijawar Group. Similar mineralization was also noted within the lower chloritic shale member of Solda Formation of the same Group. During subsequent drilling activity at a later phase (2005-09), uranium rich zones within Rohini carbonate and chloritic shale members were corroborated by the interception of mineralized bands in two boreholes drilled near Pisnari. Petrographic study of radioactive core samples reveal that uranium mineralization is closely associated with globular carbonaceous matter and sulphides along the fractures. Uranium is either adsorbed in carbonaceous matter or occurs as ultrafine inclusions of coffinite within carbonaceous matter. An additional phase of secondary uranium mineral (uranophane) is also noted in one of the boreholes. The uranium minerals, in association with sulphides, fill up moderately dipping fractures (approximately 15o towards North) which are oblique to the core axis of the inclined borehole and thus, the mineralization is characterized as hydrothermal fracture-controlled vein type mineralisation. C-HN- S analysis of carbonaceous matter occurring in close association with the uranium minerals reveal heterogeneity in composition with respect to carbon and sulfur. The present paper aims at discussing the geological, petrological and radiometric aspects of this mineralization, so as to enhance the understanding of the same.

Thermodynamic numerical simulations were carried out to determine the principal simple and complex migration species of Ca, Mg, Na, K, Al, B, Mn, Mo, Sr, and U with Cl–, OH–, SO4−2, HCO3−, and CO32− in waters at the Lomonosov diamond deposit and to estimate the saturation indexes with respect to kaolinite, Na- and Mg-montmorillonite, Mg- and Na-saponite, muscovite and paragonite, biotite, phlogopite, chromite, pyrite, plagioclase (anorthite, labradorite, and andesine), olivine (forsterite and fayalite), diopside, pyrope, gypsum, anhydrite, barite, magnesite, calcite, dolomite, talc, chrysotile, chlorite, goethite, quartz, microcline, and albite. The waters are proved not to be saturated with respect to the primary (hydrothermal) minerals. The saturation of certain water samples with uranophane suggests that this mineral is of secondary genesis. The ascent of highly mineralized deep waters shall result in the dissolution of minerals whose concentrations are near the saturation ones. To maintain the ecological standards of the discharged waters, they should be diluted and/or purified by adsorbing dissolved U on a reducing reactive barrier.

The Gabal Nasb El Atshan Upper Carboniferous-Lower Permian altered trachytes include uranium up to 3165 ppm. The paleostress and resolved shear stress analyses of the deformation systems in Gabal Nasb El Atshan area indicate that the trachyte was subjected to WNW-ESE to E-W tensile shear stress directed extensional regimes. The low-stress regions in the vicinity of extensional faults and their associated joints were favorable locations for fluid flow and the consequence alteration and U-mineralization. This occurred more extensively along the contacts between the sills of trachyte and the Hammamat sedimentary rocks; where the latter acted as a physical barrier for the alteration fluids migration outward. Alteration styles include albitization , aegirinization, arfvedsonization, chloritization and ferruginisation. The albitization is the most common sodic metasomatism , giving sanidine from Or 98.8Ab0.7 to Or62.3Ab37.6, anorthoclase from Or51.4Ab48.0 to Or12.2Ab87.6 and albite from Or 11.0Ab89.0 to Or0.8Ab99.2 . Aegirine and arfvedsonite formed due to decreasing sodium activity in the metasomatic fluids. Sodic metasomatism may be the source of uranium-enrichment, taking place during the late magmatic to deuteric processes. This was followed by a retrograde alteration of chloritization between 175 and 42 °C toward precipitation of Fe-oxides and alteration of primary uranium. Surficial low-temperature alteration remobilized and redistributed the produced uranylhydroxides and ferruginisation caused the reduction and adsorption of U forming betafite, uranophane, soddyite, umohoite, uranotile and uranopilite.

A cation exchange chromatography method employing sulfonated polysterene cation resin (DOWEX AG50-X8) was developed in order to separate rare-earth elements (REEs) from uranium-rich materials. The chemical separation scheme is designed to reduce matrix effects and consequently yield enhanced ionization efficiencies for concentration determinations of REEs without significant fractionation using solution mode-inductively coupled plasma mass spectrometry (ICP-MS) analysis. The method was applied to determine REE abundances in four uraninite (ideally UO2) samples and their associated U(VI) alteration minerals. In three of the samples analyzed, the concentration of REEs for primary uraninite are higher than those for their corresponding secondary uranium alteration phases. The results for U(VI) alteration minerals of two samples indicate enrichment of the light REEs (LREEs) over the heavy REEs (HREEs). This differential mobilization is attributed to differences in the mineralogical composition of the U(VI) alteration. There is a lack of fractionation of the LREEs in the uraninite alteration rind that is composed of U(VI) minerals containing Ca2+ as the interlayer cation (uranophane and bequerelite); contrarily, U(VI) alteration minerals containing K+ and Pb2+ as interlayer cations (fourmarierite, dumontite) indicate fractionation (enrichment) of the LREEs. Our results have implications for nuclear forensic analyses since a comparison is reported between the REE abundances for the CUP-2 (processed uranium ore) certified reference material and previously determined values for uranium ore concentrate (UOC) produced from the same U deposit (Blind River/Elliott Lake, Canada). UOCs represent the most common form of interdicted nuclear material and consequently is material frequently targeted for forensic analysis. The comparison reveals similar chondrite normalized REE signatures but variable absolute abundances. Based on the results reported here, the latter may be attributed to the differing REE abundances between primary ore and associated alteration phases, and/or is related to varying fabrication processes adopted during production of UOC.

The Hammamat sediments at Wadi Belih area are represented by greywacke and siltstones. The greywackes are immature and are fine to coarse grained and composed of quartz, feldspar and rock fragments. The siltstones consist of quartz, feldspar and hematite. The younger granites (The Gattar granites) are composed mainly of quartz and feldspars as essential minerals and biotite, hornblende, zircon, and apatite as accessory minerals. Some secondary minerals as epidote, chlorite and sericite are found. The radioactive minerals are identified by using the Quanta FEG-250 ESEM instrument which is an environmental Scanning Electron Microscope (ESEM) attached by Energy Dispersive X-ray(EDX) in the national central research (NCR). The younger granites and Hammamat rocks at Wadi Belih area contain primary uranium mineral as Coffinite, secondary minerals as Uranophane, Kasolite, Schroeckingerite and uranium bearing minerals like Columbite.

The young granites of El Maghrabiya area located at the Central Eastern Desert, the southwestern part, are intensively altered along faults, fractures, and shear zones. Microscopically, the studied granites are classified as syenogranite and the altered portion exhibits features of ferrugination and episyenitization. This granite belongs to the high silica and low calcium, iron, and magnesium granites reflecting their origin from highly fractionated potassium-rich crustal material. El Maghrabiya syenogranites are generally uraniferous especially the altered portion that is characterized by high radioactivity. The hydrothermal activity is responsible for the formation of the anomalous zone characterized by extensive episyenitization and ferrugination processes. The ferruginated syenogranite has higher concentrations of uranium and thorium than the other altered granites (episyenitized). The present study revealed that zircon, fluorite, fluorapatite, and iron oxides are the most predominant U-bearing minerals in addition to uranophane that recorded in the ferruginated variety. The studied syenogranites characterized by two thorium ranges where the fresh granite exhibits the low range (22–45 ppm) and the altered granite characterized by the higher range (68–185 ppm) indicating that there are two pulses of the magma generating El Maghrabiya young granites. Uranium and thorium of the first generation are mostly attributed to the accessory minerals and related to the magmatic processes while the second generation is characterized by low Th/U ratio and high uranium content that is enriched by the hydrothermal solutions.

Understanding the factors that govern aqueous solubility of uranyl minerals is important for predicting uranium mobility in groundwater and for designing effective remediation strategies. The uranyl-containing minerals metaschoepite [UO3∙(2H2O)] and uranophane [Ca(UO2)2(SiO3OH)2·5H2O] were synthesized and evaluated in batch solubility experiments conducted in the presence of common groundwater ions: calcium, bicarbonate/carbonate, and dissolved silica. Solid-phase characterization revealed the expected structural and thermogravimetric properties of metaschoepite and uranophane. Metaschoepite solubility in carbonate-free water followed a u-shaped pH dependency with minimum solubility near pH 8.5; uranium concentrations at pH ≳ 8.5 were approximately equivalent to the reference value for safe drinking water established by the EPA (30 μg/L). With increasing bicarbonate/carbonate concentration (1 mM – 50 mM) the solubility of metaschoepite increased, presumably due to the formation of uranyl-carbonate complexes. However, the experimental concentrations of uranium were lower than concentrations predicted from accepted complexation constants. For uranophane, equilibrium uranium concentrations were < 75 μg/L at typical groundwater concentrations of calcium and dissolved silica (pH > 7). The diversity of uranyl minerals that possibly form in the presence of common groundwater species: Ca-Mg-Na-K-Si-bicarbonate/carbonate-sulfate-chloride, has not been fully explored with respect to understanding potential mineral transformations and impacts on uranium solubility and mobility.

Raman spectroscopy studies have been performed on one hand to identify different materials related to spent nuclear fuel (SNF), and on the other hand to study the behavior of SNF at different storage conditions. Specifically, the expected oxidation of the SNF matrix under dry storage conditions and the formation of secondary phases (SP), as a result of corrosion of SNF in a deep geological repository, have been studied. In order to perform these experiments, two protocols based on the Raman spectroscopy technique have been developed. The results show U4O9/U3O7 and U3O8 as oxidation products of UO2 powder at high temperatures in air, and the secondary phase formation (rutherfordine, UO2(CO3), soddyite, (UO2)2SiO4•2H2O, uranophane alpha Ca(UO2)2(SiO3OH)2•5H2O and kasolite, PbUO2SiO4•H2O), due to uraninite corrosion under the conditions of Sierra Albarrana (Spain).

Uranium deposits form in a variety of settings. They are partially controlled by the secular evolution of Earth processes, including deposits in extension-related settings such as the intra-cratonic Rio Grande rift. Plio-Quaternary volcanism, mineral deposits, and hydrothermal spots occur along the Chihuahua Central Graben. The age of the Sierra de Gomez U-deposit is 1.8 Ma (based on LA-MC-ICP-MS dating on a uranophane monocrystal), which is contemporaneous with the late mineralization event of the Pena Blanca U-deposit, as well as Rio Grande Rift (RGR)-type deposits in Chihuahua and intraplate volcanism. Studies of fluid inclusions in fluorite and late calcite indicate the presence of hydrocarbons and CH4-rich brine. Homogenization temperatures range from 87 to 112 °C, and the mean composition (2.0 mol NaCl and 0.3 mol CaCl with CH4) is comparable to mineralizing brines in MVT deposits and carbonated hydrocarbon reservoirs. Evolution of C and O stable isotopic values for the calcite cement in the Sierra de Gomez Limestone-hosted U deposit illustrates that two separate calcite precipitation events occurred: (1) travertine filling karst structures in the presence of meteoric water and (2) U mineralization during deep hydrothermal fluid circulation that included interactions with a heat source and basement leaching. In a regional context, a metallogenic model suggests that the Chihuahua Trough area is deep enough to generate fluid migration by hydrothermal and/or compaction processes through RGR extensional faults until a favorable trapping horizon is reached. This causes uranium precipitation because water/rock interaction processes generate a local redox barrier.

Eastern Brazilian Pegmatite Province includes many topaz-bearing pegmatitic bodies. Residual melts from the Fe–K-rich alkaline Medina granite (ca. 500 Ma) formed the Serrinha pegmatite—a system of branched thin pegmatite veins hosted by pink facies of the parent granite. The colourless topaz from Serrinha pegmatite contains both mineral and fluid inclusions. Microcline (513, 476, 456 cm−1), albite (507, 479, 457 cm−1), topaz (926, 858, 267, 239 cm−1), quartz (463 cm−1), rutile (610, 444 cm−1), wolframite (884 cm−1) and uranophane (968, 788 cm−1) represent solid inclusions formed by fluid-induced processes from the pneumatolytic (∼600–400 °C) to hydrothermal (

The northern part of Um Ara alkali feldspar microgranite has subjected to extensive post-magmaticmetasomatic reworking resulting in development of amazonitized and albitized zones, reflecting K- and Nametasomatism leading to gross enrichment in U and Th towards the more evolved phases (e.g., albitizedzones). Spectrometric survey data indicate that eU in Dokhan volcanics has the range of 2 to 42 ppm withan average value of 10 ppm and in monzogranites. It varies from 3 to 13 ppm with an average of 7 ppmwhile in alkali feldspar microgranites eU contents vary from 3 to 282 ppm with an average value of 30 ppm.The (eTh) contents in Dokhan volcanics ranges from 5-51 ppm with an average 18 ppm, in monzogranitestheir content was in the range of 11 to 47 ppm with an average value of 27 ppm where it ranges from 14to 83 ppm with an average 46 ppm in alkali feldspar granite. The enhanced uranium content in alteredzones was attributed to disseminated and fracture filling uranophane, autonite, in addition to other U andTh bearing minerals (such as columbite, zircon, monazite, xenotime and fluorite). Gamma-radiation doserate and annual effective dose equivalents in mSv/y, Radium equivalent activity, external (Hex) and internalhazard index (Hin) and gamma activity index (I) for all investigated samples were calculated to assess thepotential radiation hazard for people living in dwellings made of the studied granites. Alkali feldspar graniteactivities would suggest that caution must be taken when using granites as building materials because theyhave radioactivity above the proposed acceptable level.

Syenogranitic dykes in the north of Egypt’s Eastern Desert are of geological and economic interest because of the presence of magmatic and supergene enrichment of radioactive mineralization. Zircon crystal morphology within the syenogranitic dykes allows precise definition of sub-alkaline series granites and crystallized at mean temperature of about 637 °C. The growth pattern of the zircons suggest magmatic and hydrothermal origins of radioactive mineralization. Hydrothermal processes are responsible for the formation of significant zircon overgrowth; high U-zircon margins might have occurred contemporaneously with the emplacement of syenogranitic dykes which show anomalous uranium (eU) and thorium (eTh) contents of up to 1386 and 7330 ppm, respectively. Zircon chemistry revealed a relative increase of Hf consistent with decreasing Zr content, suggesting the replacement of Zr by Hf during hydrothermal activity. Visible uranium mineralization is present and recognized by the presence of uranophane and autunite.

The studied area at Wadi Nugrus, Southeastern Desert, Egypt, is located between lat. 24°41'00'' and 24°41'35''N and long. 34°36'47'' and 34°37'09''E. The rock types are represented by layered metagabbros, biotite schists, gneisses, granodiorites, and Muscovite granites. The muscovite granite of Wadi Nugrus, is small exposure in size (~5.0 km2), emplaced along NW-SE trend, with about 0.5 - 4.5 Km in length and 100 - 250 m in width and intruding the biotite schists. The studied muscovite granite is composed mainly of plagioclases, potash feldspars, quartz, biotite and muscovite. The recorded minerals assemblage can be classified into secondary U-minerals (uranophane and meta-autunite), U-bearing minerals (uranothorite and columbite) and accessory minerals (zircon, flourite, allanite, zinnwaldite and hematite). The U/eU is more unity where, the measured chemical uranium is higher than the measured equivalent uranium in the most analyzed samples especially in trenches, which reflect disequilibrium state. The activity concentrations range from 251.72 to 1096.2 Bq·kg-1 for 232Th, from 494 to 2593.5 Bq·kg-1 for 226Ra, and from 1314.6 to 1846.7 Bq·kg-1 for 40K. The obtained radiological data show that the average internal and external hazard indices are 9.11 and 5.78, respectively which are more than unity and highly exceeding the permissible limits (International Commission on Radiation Protection, ICRP). The internal and external hazards are mainly due to 226Ra nuclei while the absorbed dose rate (nGy/h) is related to 232Th nuclei. The contributions of the three nuclei in the total absorbed dose rates and internal and external hazardous, for 226Ra, it contributes by 72% in Hin, 57% in Hex and 55% of DR, for 232Th it contributes by 24% in Hin, 37% in Hex and 36.9% of DR, while for 40K it contributes by 4.1% in Hin, 6.4% in Hex and 8.1% of DR.

The mineralogical studies on Black mica raw material revealed the presence of notable high radioactive minerals such as uranium minerals (Soddyite, Uranophane, Uranothorite, and Ishikawaite), niobium - tantalum minerals (Columbite and Plumbopyrochlore), and rare earth elements minerals (Allanite, Xenotime, and monazite). From mineralogical and chemical studies make it possible to determine optimal processing conditions, the preferred lixiviate option, and the required costs. Black mica sample was found to assay 1680 mg/Kg U, 5000 mg/Kg REEs, and 50,750 mg/Kg Nb while Ta not exceeds 5000 mg/Kg. Through applying sulfuric acid agitation leaching, 92% of uranium was dissolved under optimum leaching conditions of: 8% concentration of H2SO4 acid, 1/4 solid/liquid ratio at room temperature for 4 h reaction time, while RE2O3, Nb2O5 and Ta2O5 remained in the unattacked residue. A phosphate mixture was used for rapid dissolution of refractory minerals, REEs, Nb and Ta minerals, after fusion, which give 97.8%, 99%, and 97%, respectively, leaching efficiencies. Ion exchange, solvent extraction and precipitation techniques were used for separating and recovery of U, REEs, Nb, and Ta species from their leach liquor.

The southern Central Zone (sCZ) of the Neoproterozoic to early Palaeozoic Damara orogenic belt hosts significant uranium deposits in Namibia. Rossing South-West, a leucogranite-hosted uranium deposit in the sCZ is partitioned into two sections; north-easterly and south-westerly sections with the latter (termed mining licence 120, i.e. ML120) forming the locus of this investigation. The deposit lies within the vicinity and to the west of the Welwitschia lineament which served as a conduit for mineralized fluids along with the Rossing and Husab deposits. Mineralogy and major and trace element geochemistry of the uraniferous leucogranites in ML120 suggest they are S-type granites derived from a sedimentary source as evidenced by the presence of igneous phases of garnet and cordierite together. Microscope and electron microprobe results from 133 powdered, drill core and hand samples prove that the deposits host similar primary uranium mineralization (chiefly uraninite which mainly exist as independent uranium minerals) and similar secondary U mineralization. At Rossing-SW U minerals include uraninite, coffinite, pitchblende, betafite, uranophane, betauranophane, carnotite, gummite and might partially exist as Th isomorphs. Mineralization at all locales is associated with post-tectonic D and E-type sheeted leucogranites containing quartz, alkali-feldspar and variable amounts of plagioclase producing rocks of variable compositions from tonalite to alkali-feldspar granite. Total reserves calculated at a cut-off grade of 100 ppm were reported as 171 Mt of ore at 376 ppm for Rossing and 205 Mt of ore at 497 ppm for Husab (probable). The Rossing-SW orebody is open-ended however total inferred resources stand at 304.4 Mt of ore at 235 ppm while measured resources stand at 8830t ore at circa 231 ppm. A comparison of the geological parameters (uranium mineralogy, leucogranite petrology and geochemistry) suggests similar ore composition. Consequently, ore from Rossing-SW's ML120 area could be processed at existing metallurgical plants (such as at Rossing or Husab) with a probable increase in U3O8 yield.

223Ra,224Ra,226Ra, and228Ra isotopes have been measured in groundwaters from depths ranging 50–900m in fractured crystalline bedrock (Forsmark, Sweden) to understand the reason for elevated (up to 150μg/L) aqueous uranium (Uaq) at 400–650m depth. Ra isotope data is interpreted alongside previously reported222Rn,234U, and238U data, as well as PHREEQC geochemical modelling and uranium mineralogy. A novel, [223Ra/226Ra]GW-based approach (where brackets and “GW” subscript refer to expression of an activity ratio measured from groundwater) to groundwater residence time estimation shows that elevated [Uaq] is most common in Holocene-age groundwaters of marine origin. Although these groundwaters are geochemically reducing, the [223Ra/228Ra]corr(where “corr” subscript refers to a correction applied to compare [223Ra/228Ra]GWto the more commonly reported [226Ra/228Ra]GW) suggest that they interact with U-rich pegmatites containing Proterozoic- and Palaeozoic-age Ca-U(VI)-silicate minerals, which are undersaturated in the present groundwaters. Local aqueous U(VI) can be stabilized in Ca2UO2CO30complexes at pe-values as low as −4.5 but is susceptible to reduction after a modest decrease in pe-value, alkalinity, or Ca concentration. The [223Ra/228Ra]corrand [224Ra/228Ra]GWalso suggest that U(VI)aqprecipitates as UO2+Xat the interface between marine and non-marine groundwaters. From these data, local [Uaq] is proposed to be governed by on-going water-rock interaction involving old U(VI)-minerals.

Um Ara area is located in the extreme south Eastern Desert of Egypt between 581400mE-584900mE and 2503000mN-2504600mN. The area comprises distinct tectono-stratigraphic units beginning with the oldest as follows: Dokhan volcanic and post-collision granitoids (monzogranite, and alkali feldspar granite), and associated with dykes and quartz veins. The granite affected by deuteric K-metasomatism (microclinization) followed by Na-metasomatism (albitization) causing zonation in this part of the pluton. The high radioactivity in the anomalous sites is structurally controlled (strong shearing, fracturing and jointing). The intensity of mineralization is especially significant along joint sets striking NNW-SSE, NNESSW and NE-SW trending. The spacing among these joints ranges from few mm up to about 5 cm. locally, the joints are filled with kaolinite and other alteration products including hematite and Mnoxides. Geochemically, Um Ara granites trenches and core samples show a relative enrichment in K2O compositions due to plagioclase destruction and formation of muscovite/sericitization. Um Ara granites trenches and core samples have variable total REEs contents 117.41 to 308.28 and 256.51 to 397.22 ppm respectively. ΣLREEs in trenches and core samples range from 108.47 to 298.41ppm and from 236.84 to 384.78 ppm respectively, whereas ΣHREEs range from 5.48 to 14.01 ppm and from 12.44 to 19.67 ppm respectively. The lowest concentration of total REEs in core samples is at 100m depth, while the highest values at 145m depth. Um Ara granites trenches, U contents vary from 154 to 506 ppm with an average of 245.7 ppm, and Th contents vary from 47 to 415 ppm with an average of 165.4 ppm. Core samples granite, U contents vary from 128 to 349 ppm with an average of 237.3 ppm, and Th contents vary from 45 to 146 ppm with an average 107.4 ppm. Visible secondary uranium mineralization is represented mainly by uranophane and β-uranophane. Uranium is also contained within a range of U-bearing accessory minerals, mainly fluorite, monazite, xenotime, allanite and zircon. The secondary processes played a main role in uranium enrichment (uranium added to these granitic sites post-magmatically). Um Ara altered granites trenches and core samples rocks are an abnormal radiation and have an extension. So, these anomalies are suitable to be a place for uranium extraction. The result is the continuous of its mining work besides leachability experiments.

The present study deals with the mineralogical and radioactive characteristics of the pegmatitic rocks at Gabal El-Urf area, Central Eastern Desert of Egypt.The zoned pegmatites of El-Urf area are composed of three enriched mineral zones; extremely milky quartz core, intermediate mica zone and feldspars wall zone.The identified separated heavy minerals in the studied pegmatite can be grouped into three mineral groups; the primary minerals (pyrite, molybdenite, rutile, magnetite, thorianite, zircon, columbite and garnet), the secondary minerals (uranophane, kasolite, uranothorite, samarskite, uranopolycrase, dravite, ilmenorutile, allanite and titanite.) and the gangue minerals (lanarkite, barite, hematite, ilmenite, goethite, apatite, monazite and kamitugaite).The studied zoned pegmatites hosting or acting as a source for uranium and rare metals (Zr, Y, Nb and Th) mineralizations. Multistage deformation, magmatic and hydrothermal processes accompanied by events of uranium mineralization with the associated rare metals mineralizations in different episodes affected Gabal El-Urf zoned pegmatites.The rare metals can be originated through magmatic and hydrothermal fluids under the restrictive sets of conditions that commonly prevail in these zoned pegmatites. The magmatic and hydrothermal processes enriched with rare metals mineralization accompanied by event of an intensive tectonic structure affected Gabal El-Urf pegmatites.

The Thelon basin, Nunavut, shares many similarities with the uranium-producing Athabasca basin, Saskatchewan; however, the uranium deposits associated with the Thelon basin are still poorly understood. The Kiggavik project area (AREVA Resources Canada) is located near the northeastern terminus of the Thelon basin and comprises multiple uranium deposits hosted exclusively in basement rocks. The Bong deposit is hosted dominantly by Neoarchean metagraywacke of the Woodburn Lake group. A five-phase metallogenetic model is proposed for the Bong deposit, with three stages of uraninite identified. The premineralization phase is characterized by host-rock silicification. Mineralization is separated into three main stages. Stage 1 uraninite (U1; ca. 1500 Ma) is preserved in highly fractured and altered disseminated grains that are overgrown by later stages of uraninite. Stage 2 uraninite (U2; ca. 1100 Ma) forms veinlets parallel to D 1 foliation and coats and fills fractures in organic matter nodules and blebs. Stage 2 uraninite is associated with pervasive illite that formed from ~190°C fluids ( δ 18 O: −6.4‰, δ 2 H: −97‰), which remobilized much of Stage 1 uraninite and completely overprinted Stage 1 alteration. At ~1000 Ma an oxidizing fluid deposited uraninite along redox fronts (U3) while altering and remobilizing Stage 1 and 2 uraninite. Post-uranium-oxide minerals include drusy quartz, calcite, and illite accompanied by uranyl phases (e.g., uranophane, Ca-U).

Development of unconventional shale gas wells can generate significant quantities of drilling waste, including trace metal-rich black shale from the lateral portion of the drillhole. We carried out sequential extractions on 15 samples of dry-drilled cuttings and core material from the gas-producing Middle Devonian Marcellus Shale and surrounding units to identify the host phases and evaluate the mobility of selected trace elements during cuttings disposal. Maximum whole rock concentrations of uranium (U), arsenic (As), and barium (Ba) were 47, 90, and 3333 mg kg−1, respectively. Sequential chemical extractions suggest that although silicate minerals are the primary host for U, as much as 20% can be present in carbonate minerals. Up to 74% of the Ba in shale was extracted from exchangeable sites in the shale, while As is primarily associated with organic matter and sulfide minerals that could be mobilized by oxidation. For comparison, U and As concentrations were also measured in 43 produced water samples returned from Marcellus Shale gas wells. Low U concentrations in produced water ( Geochemical modeling to determine mobility under surface storage and disposal conditions indicates that oxidation and/or dissolution of U-bearing minerals in drill cuttings would likely be followed by immobilization of U in secondary minerals such as schoepite, uranophane, and soddyite, or uraninite as conditions become more reducing. Oxidative dissolution of arsenic containing sulfides could release soluble As in arsenate form under oxic acidic conditions. The degree to which the As is subsequently immobilized depends on the redox conditions along the landfill flow path. The results suggest that proper management of drill cuttings can minimize mobilization of these metals by monitoring and controlling Eh, pH and dissolved constituents in landfill leachates.

Uraninite is a mineral considered as an analogue of the spent fuel, and the study of its alteration products has been used to predict the secondary phases produced during the fuel storage under specific environmental conditions. In this work, we study by Raman spectroscopy the alteration by weathering of the primary uraninite from the uranium deposit of Sierra Albarrana. The identification of the different secondary phases is based on the analysis of the symmetrical stretching vibration of the uranyl group (UO 2 2+ ), which allows the identification of individual uranyl phases and can be used as a fingerprint. Additionally, we show in this work a new approach to perform a semi-quantitative analysis of these uranium minerals by means of Raman spectroscopy. From this analysis we found the next sequence of alteration products: rutherfordine in contact with the uraninite core, then a mixture of uranyl silicates: soddyite, uranophane alpha and kasolite. Soddyite prevails in the inner part while uranophane alpha predominates in the outer part of the sample, and kasolite appears intermittently (1.0–3.3 mm; 4.6–7.1 mm and 8.8–10 mm).

Five lamprophyre dikes (L1-L5) intruded Abu Rusheid rocks (cataclastics and monzogranite) in the South Eastern Desert of Egypt along shear zones with NNW-SSE and E-W. The two sets of dikes differ in age, mineralization, and geochemical aspect. The NNW-SSE trending dikes (L1 and L2) are polymineralized and dislocate the E-W (L3, L4, and L5) trending dikes. These dikes underwent multistage of hydrothermal processes (ferrugination, fluoritization, kaolinitization, and calcification). They are characterized by common box works (physical trap) filled by incoming mineralization, and their feldspars and micas are relatively altered to clay minerals (chemical trap). From the mineralogical point of view, the cataclastic rocks are rich in base metals (pyrite, sphalerite, molybdenite, chalcopyrite, and galena), radioactive minerals (thorite, uranophane, kasolite, uranothorite), and accessories phases (zircon, xenotime, cassiterite, molybdenite, copper, columbite, and fluorite). L1 and L2 lamprophyre dikes contain U minerals (uranophane, kasolite, autunite, and torbernite), Mn-franklinite, woodruffite, xenotime, fluorite, silver, copper, and scheelite. L3 contains Zn and U minerals, whereas L4 and L5 contain Zn minerals only. The source magma producing lamprophyre dikes (L1 to L4) are peralkaline to alkaline, whereas L5 lamprophyres are mainly calc-alkaline in character; they were generated from the mantle and had formed in a post-collision tectonic setting with extensive Ti-rich metasomatism. The average ΣREE content in (L1 and L2) lamprophyres is 8006 ppm. REE patterns display clear concave upward pattern of W-type tetrad effect in the REE pattern accompanied by enrichment of the HREE over the LREE and marked negative Eu anomaly due to secondary mobilization of REEs.

Wadi Murrah area is located in the extreme south Eastern Desert of Egypt. The area comprises four distinct tectono-stratigraphic units beginning with the oldest as follows: ophiolitic assemblage (dismembered ophiolitic rocks and ophiolitic melange), arc assemblage (metavolcanics, metagabbros, and older granites), post-collision granitoids (monzogranite, syenogranite, and alkali feldspar granite), and associated with dykes and quartz veins. The identified minerals in the samples taken from the anomalous sites of syenogranite and alkali feldspar granite in the northern part of the study area are represented by uranophane, autonite, meta-autonite, uranothorit, columbite, zircon, fluorite, monazite, xenotime, sphene, allanite, and apatite. The anomalous samples have U and Th average contents for syenogranites and alkali feldspar granites 82 and 104.4 ppm and 209 and 115.2 ppm, respectively. The high radioactivity in the anomalous sites is controlled lithologically and structurally. The secondary processes played a main role in uranium enrichment (uranium added to these granitic sites post-magmatically).

The granite dike swarms intruding the older granitiod and occasionally the younger gabbros were emplaced througha shear zone extending in NE-SW direction. These dikes are composed mainly from alkali feldspar granites. They are finegrained, hard and compact vary in color from pink, red, reddish brown and occasionally bloody red. It is affected by varyingdegrees of alterations and subjected to deformation processes. Mineral segregations and pegmatite pockets are encounteredalong deformed and altered zones. Alkali feldspars mainly perthites and microcline, quartz, little sodic plagioclaseand biotite represent the main rock forming minerals. These dikes possess high contents of radioelements especiallythorium. The eTh contents range from 63.9 ppm to 2523 ppm with an average 465.8 ppm where the eU content range from25ppm to 497.9 ppm with 106.3 ppm average. The mineral segregations give the highest level of eU and eTh contents reach upto 7331 ppm and 1386 ppm respectively. Secondary uranium minerals (uranophane and curite), thorium minerals (thorite) andU- and Th-bearing minerals (Zircon, allanite, columbite, samarskite, xenotime, monazite, kasolite and titanite) are identified.Other non radioactive minerals such as magnetite, goetite, hematite, cronstedtite, pyrite, fluorite, garnet are also identified.Also, chemical analyses (XRF) revealed presence of high concentration of U, Zr, Y, Nb, Ba, Zn, Rb and Sr in addition to presenceof V, Pb, Ni and Cr. Au and Pt are also present

Korea has suffered from high U concentrations in some groundwater, especially in Daejeon near the central Ogcheon metamorphic belt. However, clear explanation has not been yet reported for the uranium sources in groundwater. This study is focused on identifying the potential uraniferous host rocks and finding the exact U-minerals serving as uranium sources in groundwater near Daejeon, Korea. For this work, we performed an in situ gamma ray spectrometer survey and a laboratory microscopic study with electron micro-probe analysis. The measurements for radioactive element content did not show any prominent K- and Th-anomaly spots, but they did result in several observations of considerable U-anomalies in pegmatite and hydrothermally altered granite, in which uraninite, coffinite and uranophane were found by electron micro-probe analysis. The occurrences of U-minerals are the first such discovery except in the low-grade U deposits of the Ogcheon metamorphic belt in Korea. All observed U-minerals were intimately associated with hydrothermal alteration. The remarkably low Th/U ratios in the studied uraniferous rocks also suggest that the U enrichment was genetically related to a post-magmatic hydrothermal process. However, many of the uraniferous parts were controlled by a reducing environment and occurred near the border between graphite-rich mica-schist and Jurassic leucocratic granite. The findings on these uraniferous rocks can be used in elucidating the source of highly enriched U groundwater in granite aquifers as well as in understanding the occurrence of igneous U-minerals, which has not been previously reported in Korea.

An economically important rare-metal mineralization is recorded in the cataclastic rocks at Wadi AbuRusheid area, South Eastern Desert of Egypt.Radiometric measurements of the main varieties of cataclastic rocks (protomylonites, mylonites,ultramylonites) show that their equivalent thorium (eTh) content is 7560, 8660 and 6210 ppm, whereas theequivalent uranium (eU) is 2544, 4170 and 790 ppm respectively.Microscopic examination, X-ray diffraction (XRD) and grain counting techniques revealed that thorite,zircon and columbite are the predominant radioactive minerals in all rock varieties , together with minoramounts of xenotime, cassiterite and sulphides. Beside these minerals, uranophane, kasolite and metaautuniteoccur as inclusions in other minerals.Physical upgrading of these minerals was carried out using gravitative separation technique. Applyingthe proposed flowsheet, it is possible to attain a good concentrate for these minerals with an acceptablerecovery. It is recommended to subject the final concentrates to hydrometallurgical treatments to extractthe important metals.

Khour Abalea in Abu Rusheid area is located at the midst part of the cataclastic rocks having U-shapedIt was formed as a result of deep strike-slip faults, some forming shear zone in some trends. Two forms ofpegmatites have been distinguished (pockets and veins) occurring within the cataclastic rocks as hostedrocks. Petrographically, they consist of quartz, orthoclase, microcline and micas.The identified minerals in the studied pegmatites can be grouped into primary uranium minerals(uraninite), secondary uranium minerals (kasolite, uranophane and meta-autunite), thorium minerals(thorite and uranothorite), the niobium-tantalum minerals (columbite, ferro-columbite, samarskite, euxeniteand fergusonite), the accessories (zircon, monazite, cassiterite, pyrite and fluorite) and mica (muscovite,phlogopite and fluor-phlogopite) as well as the opaques (hematite and goethite).Geochemically, the studied pegmatite (S-type) are calc–alkaline and peraluminous in nature. It is highlyfractionated possibly due to hydrothermal alterations. The REEs display clear tetrad effect of M-typeaccompanied with relative enrichment of the HREE over the LREE and marked negative Eu anomaly(Eu/Eu* =0.03 to 0.36). The calculated tetrad effect in the pegmatite demonstrates clear tendency towardsthe ratios of the common isovalents such as Zr/Hf, Nb/Ta and Y/Ho. However, the tetrad effect seems notto be mutual with the content of Na2O and Rb/Sr. The absence of coherence between tetrad effect and sodaor potassic contents may indicate insignificant role of the Na- or K-metasomatism in developing the tetradeffect.Detailed spectrometric survey of the study pegmatite revealed their enrichment of eU (49-306 ppm)and eTh (76-634 ppm) and the potential anomalous radioactivity is attributed to both magmatic andhydrothermal processes.

The metamorphosed sandstones exposures occur in two locations in Wadi Sikait. The exposed rocks in this area are ophiolitic melange, metamorphosed sandstones, porphrytic granites invaded by post-granite dykes (lamprophyres) and quartz-fluorite veins. The uranium contents measured radiometrically range from 3 to 41.97 ppm, with an average of 12 ppm, while the chemically measured are in the range from 20 to 100 ppm and averaging 50.83 ppm. High uranium contents are mainly attributed to the presence of secondary uranium minerals (uranophane and autonite), accessory minerals (monazite, zircon, allanite and xenotime) and U-bearing minerals (muscovite, biotite, chlorite, iron oxides and clays). P- and D-factors indicate disequilibrium in U-decay due to addition of uranium in these rocks. Since radioactive secular equilibrium of the young age deposits have not yet reached, therefore, the activity ratios (AR) of 230Th/234U in the studied rocks is very small and ranges from 0.43 to 1.3. Radon exhalation rates of the studied rocks were also measured using ‘‘Sealed Can technique” and indicated the presence of subsurface and surface uranium anomaly which confirms the previous results. Key words: Metamorphosed sandstones, uranium, minerals, Wadi Sikait.