Geochemistry and environmental impact of neutral drainage from an uraniferous coal waste heap

Křı́bek, Bohdan; Šráček, Ondra; Mihaljevič, Martin; Knésl, Ilja; Majer, Vladimı́r

doi:10.1016/j.gexplo.2018.05.001

Cited by 11 publications

(11 citation statements)

References 58 publications

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“…Under these conditions, gypsum (CaSO 4 •2H 2 O) precipitation can limit the concentrations of Ca. Additionally, pCO 2 can reach up to two orders of magnitude above atmospheric pCO 2 in WRSFs because of carbonate-mineral dissolution and limitations on gas exchange with the atmosphere [44,[62][63][64][65][66]. Given the dependence of U sorption on Ca concentrations and pCO 2 [16,19,20,67], we assessed how a U-HFO system would respond in hypothetical scenarios wherein pyrite oxidation and carbonate-mineral dissolution reactions progressed to a higher degree, i.e., to the point at which Ca concentrations became controled by gypsum mineral saturation.…”

Section: Modeling Sorption During the Application Of U-rich Gneiss Ef...mentioning

confidence: 99%

“…Although there are many studies of U geochemistry in mine wastes, these have predominantly focused on acidic drainage (pH < 6) where CCU complexation is negligible [12,18,19,[27][28][29][30][31][32][33][34][35][36][37]. Neutral-rock drainage (NRD) (e.g., pH ≥ 6 [38]) is typically characterized by high alkalinity (hundreds of mg/L as CaCO 3 ) and dissolved Ca reaching hundreds of mg/L, i.e., orders-of-magnitude above typical fresh groundwaters [39][40][41][42][43][44]. Under these conditions, CCU complexation (Reaction (3)) might exacerbate U release.…”

Section: Introductionmentioning

confidence: 99%

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Geochemical Controls on Uranium Release from Neutral-pH Rock Drainage Produced by Weathering of Granite, Gneiss, and Schist

Skierszkan

Dockrey²,

Mayer

et al. 2020

Minerals

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We investigated geochemical processes controlling uranium release in neutral-pH (pH ≥ 6) rock drainage (NRD) at a prospective gold deposit hosted in granite, schist, and gneiss. Although uranium is not an economic target at this deposit, it is present in the host rock at a median abundance of 3.7 µg/g, i.e., above the average uranium content of the Earth’s crust. Field bin and column waste-rock weathering experiments using gneiss and schist mine waste rock produced circumneutral-pH (7.6 to 8.4) and high-alkalinity (41 to 499 mg/L as CaCO3) drainage, while granite produced drainage with lower pH (pH 4.7 to >8) and lower alkalinity (<10 to 210 mg/L as CaCO3). In all instances, U release was associated with calcium release and formation of weakly sorbing calcium-carbonato-uranyl aqueous complexes. This process accounted for the higher release of uranium from carbonate-bearing gneiss and schist than from granite despite the latter’s higher solid-phase uranium content. In addition, unweathered carbonate-bearing rocks having a higher sulfide-mineral content released more uranium than their oxidized counterparts because sulfuric acid produced during sulfide-mineral oxidation promoted dissolution of carbonate minerals, release of calcium, and formation of calcium-carbonato-uranyl aqueous complexes. Substantial uranium attenuation occurred during a sequencing experiment involving application of uranium-rich gneiss drainage into columns containing Fe-oxide rich schist. Geochemical modeling indicated that uranium attenuation in the sequencing experiment could be explained through surface complexation and that this process is highly sensitive to dissolved calcium concentrations and pCO2 under NRD conditions.

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Section: Modeling Sorption During the Application Of U-rich Gneiss Ef...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Geochemical Controls on Uranium Release from Neutral-pH Rock Drainage Produced by Weathering of Granite, Gneiss, and Schist

Skierszkan

Dockrey²,

Mayer

et al. 2020

Minerals

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“…The toxicity and real impact on the environment of coal-waste dumps constantly bring to light many contradictions [1][2][3][4][5][6][7]. Theoretically, such facilities-properly prepared and protected-should be neutral to the surroundings [8,9], which in Poland is regulated by legal provisions, including the Environmental Protection Law (Act of 27 April 2001).…”

Section: Introductionmentioning

confidence: 99%

“…The enrichment factor is used to assess the degree of anthropogenic influence on ecosystems. The results determine five classes: deficiency to minimal enrichment (<2), moderate enrichment (2-5), significant enrichment (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), very high enrichment , and extremely high enrichment (>40). • Translocation factor (TF): TF = C n R n , where C n is the element content in the aboveground parts of the plant, and B n is the concentration of the same element in the roots [58,59].…”

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confidence: 99%

Element Cycling at Thermally Active Coal-Waste Dumps: A Case Study of Calamagrostis epigejos and Solidago canadensis

Abramowicz,

Rahmonov

2024

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Coal-waste dumps in the Upper Silesian Coal Basin are usually colonized by tall grass Calamagrostis epigejos and Solidago canadensis, which influence the direction of vegetation formation and the soil chemistry. The aim of this study is to analyze and determine the content of major elements (Fe, Ca, P, Mg, Al, Na, K, S) and trace elements (Mo, Cu, Pb, Zn, Ni, Co, Mn, Sr, Cd, Cr) in aboveground and underground parts of the plants and the soil at the thermally active coal-waste dump. Analysis of the heavy metal concentrations reveals that they are higher in plant materials than in soil materials within the root zone of the plants. Environmental indicator analysis (geoaccumulation index, enrichment factor, translocation factor) shows that the studied species exhibit varying degrees of pollution, with cadmium and zinc showing the highest accumulation rates. The content of elements in the analyzed species, both in washed and unwashed specimens, does not show significant differences, which is confirmed by the enrichment factor. Statistical analysis shows a positive correlation between the amount of microelements in plants (roots, aerial part) and soil samples in both thermally active and inactive zones. These findings broaden the scientific inquiry and hold practical significance for the reclamation of post-industrial areas.

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“…The results indicated that coal-fired power plants had no significant influence on the radioactive concentration in the surrounding soil. Bohdan et al [11] reported the geochemistry and environmental impact of neutral drainage from an uraniferous coal waste pile, investigated an impact of former coal waste pile on local drainage, and finally concluded the amount of uranium element in sediments decreased with the distance from the plie. Noli et al [12] monitored the seasonal changes of natural radionuclides in lake sediments and water of the lignite mining area in northwest Greece, and found that most radionuclides have significant differences between cold and warm periods, and the accumulation amount was related to the distance from pollution sources.…”

Section: Introductionmentioning

confidence: 99%

Basic Characteristics of Coal Gangue in a Small-Scale Mining Site and Risk Assessment of Radioactive Elements for the Surrounding Soils

Wang

et al. 2021

Minerals

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The accumulation/improper treatment of coal gangue will not only lead to waste of land, but also cause environmental pollution. Especially the impact of radioactive elements on the surrounding ecological environment is widely concerned by many scholars. In this study, the concentration of radioactive elements (uranium (U) and thorium (Th)) of small-scale coal gangue mining site and surrounding soil in the northern region of Xieqiao coal mine were tested, the material composition of coal gangue was analyzed via XRF and XRD, the modes of occurrence of U and Th elements were investigated, and their potential ecological risks and ecological effectiveness were evaluated. The results show that the clay minerals with high content in coal gangue are the key minerals for the adsorption of uranium and thorium in coal gangue. The specific activity of two radioactive elements (U and Th) in soil is much lower than that of coal gangue. With the increase of the distance from the soil collection point to the gangue piles and the depth of the soil profile, the specific activities of the two radioactive elements decrease gradually. On the basis of the concentration curve, the range of the radioactive contamination halo of gangue piles is limited (≤30 m), speculating qualitatively that the gangue dump has no significant influence on the radioactivity of the surrounding water. The modes of occurrence of U and Th in coal gangue and soil are altered. According to the index of geo-accumulation, Th is easier to accumulate in soil environment, but Th and U pollution in soil is not obvious. In contrast to U element, the active state of Th element in soil is generally affected by exogenous (coal gangue) export, which may have a potential environmental effects. This study provides a research idea for the investigation of radioactive element pollution to the surrounding soil in small-scale coal gangue plies.

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Geochemistry and environmental impact of neutral drainage from an uraniferous coal waste heap

Cited by 11 publications

References 58 publications

Geochemical Controls on Uranium Release from Neutral-pH Rock Drainage Produced by Weathering of Granite, Gneiss, and Schist

Geochemical Controls on Uranium Release from Neutral-pH Rock Drainage Produced by Weathering of Granite, Gneiss, and Schist

Element Cycling at Thermally Active Coal-Waste Dumps: A Case Study of Calamagrostis epigejos and Solidago canadensis

Basic Characteristics of Coal Gangue in a Small-Scale Mining Site and Risk Assessment of Radioactive Elements for the Surrounding Soils

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