Evolution of uranium distribution and speciation in mill tailings, COMINAK Mine, Niger

Déjeant, Adrien; Galoisy, Laurence; Roy, Régis; Calas, Georges; Boekhout, Flora; Phrommavanh, Vannapha; Descostes, Michaël

doi:10.1016/j.scitotenv.2015.12.027

Cited by 32 publications

(18 citation statements)

References 55 publications

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“…The second set of samples comprised two components: a ground uranium ore and its related fresh tailing (Déjeant et al, 2016). The ore was sampled after grinding and before selective U extraction.…”

Section: Methodsmentioning

confidence: 99%

Mapping 238U decay chain equilibrium state in thin sections of geo-materials by digital autoradiography and microprobe analysis

Angileri

Sardini

Donnard³

et al. 2018

Applied Radiation and Isotopes

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A new approach is proposed in order to spatially localize and determine the equilibrium state of natural decay chains on hand-scale geological samples, thanks to a combination of three techniques: 1) Elementary chemical mapping by microprobe; 2) Alpha autoradiograph by gaseous detectors and 3) bulk alpha particle spectrometry. The quantitative nature of alpha autoradiograph and its comparison with U chemical maps allows to locate radioactive equilibrium state in four samples. This equilibrium state was confirmed by alpha spectrometry analysis.

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Section: Methodsmentioning

confidence: 99%

Mapping 238U decay chain equilibrium state in thin sections of geo-materials by digital autoradiography and microprobe analysis

Angileri

Sardini

Donnard³

et al. 2018

Applied Radiation and Isotopes

Self Cite

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“…Generally speaking, the maximum transmission distance cannot exceed several hundred meters, so the power consumption is often small, generally less than 100 mW. As long as a communication protocol technology is embedded between various electronic devices, data transmission and sharing can be realized in a short distance, which is very convenient 6,7 …”

Section: Mineral Remote Sensing Monitoring Technologymentioning

confidence: 99%

Internet of Things technology in mineral remote sensing monitoring

Liu

Dhakal

2020

Circuit Theory & Apps

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At present, the rapid development of the national economy consumes a lot of mineral resources, but the national resource extraction efficiency is low. The traditional prospecting methods consume time, money, and personnel, which cannot meet the national demand for resources in a short time. Therefore, technological innovation is needed to reduce consumption in all aspects. With the continuous development of Internet of Things technology, its application is also more extensive. This paper studies the application of Internet of Things technology in mineral remote sensing monitoring. First of all, this research mainly uses the wireless communication technology in the Internet of Things to achieve data transmission and sharing in a short distance and, second, based on the remote sensing monitoring results of the mine environment to comprehensively understand the mining area and find the suitable mining mineral resources at the fastest speed; finally, the dynamic frame time slot ALOHA algorithm is used to estimate the existing data to ensure the availability of the data. The experimental data show that vector point encryption is performed on the center line of the mine at intervals of 10, 15, 20, 30, and 50 m, respectively, and the dynamic frame slot algorithm is used to calculate the appropriate mine mining curve radius. The experimental results show that the application of Internet of Things technology in mineral remote sensing monitoring can accelerate the mining of mineral resources.

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“…These mill tailings were then stored near the ore processing plants, as is the case for mines operating today overseas (see for instance Déjeant et al (2016) for Niger and Robertson et al (2019) for Canada).…”

Section: Introductionmentioning

confidence: 99%

A multi-scalar study of the long-term reactivity of uranium mill tailings from Bellezane site (France)

Ballini

Chautard

Nos

et al. 2020

Journal of Environmental Radioactivity

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The mill tailings from uranium mines constitute very low-level, long-lived, radioactive process waste. Their longterm management therefore requires a good understanding of the geochemical mechanisms regulating the mobility of residual U and 226 Ra. This article presents the results of the detailed characterization of the tailings resulting from the dynamic leaching processes used on the ore of the La Crouzille mining division and stored at the Bellezane site (Haute-Vienne, France) for over 25 years. A multi-scalar and multidisciplinary approach was developed based on a study of the site's history, on the chemical, radiological and mineralogical characterizations of the solid fraction of the tailings, and on porewater analyses. These were supplemented by thermodynamic equilibrium models to predict the long-term mobility of U and 226 Ra. Weakly acidic (pH = 6.35) and oxidizing (Eh = 138 mV/SHE) porewaters had a sulfated-magnesian facies ([SO4]tot = 43 mmol/L ; [Mg]tot = 33 mmol/L) with an accessory calcium bicarbonate component (TIC = 25 mmol/L ; [Ca]tot = 13 mmol/L) and dissolved concentrations of uranium and 226 Ra of 12x10-6 mol/L and 0.58 Bq/L respectively. Ultra-filtration at 10 kDa indicated the absence of colloidal phases. The characterization of the tailings confirmed their homogeneity from a radiological, chemical and mineralogical point of view. The residual U and 226 Ra concentrations measured in the solid were 160 ppm and 25 Bq/g respectively, in accordance with the initial ore grades and mill yields, or more than 99% of the total stock. In terms of chemical and mineralogical composition, the tailings were mainly composed of minerals from the granitic ore (quartz, potassium feldspar, plagioclases and micas) in association with their weathering products (smectite and ferric oxyhydroxides) and with neo-formed minerals following rapid diagenesis after neutralization of the tailings before their emplacement (gypsum and barite). All these minerals are effective traps for the retention of U and 226 Ra. The uranium is distributed partly in micrometer scale uraninite and coffinite refractory phases embedded in grains of quartz, and partly sorbed to smectite and ferric oxyhydroxides. The 226 Ra on the other hand is trapped mainly within the barite. The aqueous concentrations of U and 226 Ra could be described using a thermodynamic approach so that their long-term mobility can subsequently be assessed by modeling. The paragenesis of the tailings could be seen to be stable over time with the exception of neo-formed gypsum and calcite, which will gradually dissolve. The presence of retention traps offering surplus capacity, i.e. smectite, ferric oxyhydroxides and barite, will maintain the U and the 226 Ra at very low aqueous concentrations, even under oxidizing conditions. Moreover, the low permeability of the mill tailings leads, in the case of 226 Ra, to behavior dictated only by the radioactive decay. Highlights (no more than 85 characters, including spaces)  U mill tailings from Bellezane (France) were studied...

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Evolution of uranium distribution and speciation in mill tailings, COMINAK Mine, Niger

Cited by 32 publications

References 55 publications

Mapping 238U decay chain equilibrium state in thin sections of geo-materials by digital autoradiography and microprobe analysis

Mapping 238U decay chain equilibrium state in thin sections of geo-materials by digital autoradiography and microprobe analysis

Internet of Things technology in mineral remote sensing monitoring

A multi-scalar study of the long-term reactivity of uranium mill tailings from Bellezane site (France)

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