Hubert Bril
Centre national de la recherche scientifique
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Geoderma | 2003
Catherine Néel; Hubert Bril; Alexandra Courtin-Nomade; Jean-Pierre Dutreuil
Abstract Remediation and revegetation of abandoned mined sites is often complicated by the lack of knowledge on factors leading to soil development on anthropogenic mine waste materials. Natural soil development has been examined on 35-year-old sulphide-rich waste deposits of a former gold mine. The muddy waste materials were discharged into a small settling basin (9850 m 2 ) by successive floods during mining activity (1959–1964). The aim of the study was to identify factors explaining the actual uneven distribution of vegetation cover on the abandoned waste materials. These stratified anthropogenic deposits generated a young A–C Entisol at a relatively slow rate (0.25–0.7 cm year −1 ). Oxidation of primary sulphides is recognised as the main pedological process involved. The spatial variations of the soil thickness and morphological features reflect those of vegetation cover density and diversity. Based on pedological, sedimentological, mineralogical and hydrochemical measurements, our results show that the rate of soil development was mainly governed by inherited factors of parental waste materials such as the initial sulphide and clay contents, the granulometry and the chemical composition. From the waste discharge pipe (Zone 1) to the basin boundaries (Zone 3), the porosity, granularity and content in potentially toxic elements decrease (Pb, As), whereas the pH and the clay content increase. In the upstream Zone 1, the oxidation of sulphide minerals produced waste acidification and release of toxic elements. As a result, the soil As and Pb concentrations reached levels hundred to thousand times higher than those of regulatory guidelines. In the downstream Zone 3, clay minerals buffered the waste acidification and contributed to the maintenance of tailings water saturation resulting in leaching of soluble arsenate. The heterogeneous mining area is, thus, likely to generate different mine soils over short distances (10 m). An acidic sulphate soil with a specific sulphuric or gypsic B horizon is expected in Zone 1, while a soil free of Fe oxides or As, Pb-enriched sulphate accumulation is expected in Zone 3.
Bulletin De La Societe Geologique De France | 2002
Alexandra Courtin-Nomade; Catherine Néel; Hubert Bril; Mélanie Davranche
Tailings of two former mines located in the French Massif Central (La Petite Faye in Creuse Dpt. and Enguiales in Aveyron Dpt.) were studied in order to forecast the mobility of arsenic and others metallic trace elements (MTE) resulting from sulphides oxidation. Arsenic and MTE could potentially be toxic as a contamination in the sediments, soils, waters... The formation of new products resulting from the alteration processes is especially interesting because of the abilities of these products to trap these metals or metalloids. We have focussed our study on the alteration products in order to determine their role in the immobilisation of arsenic and others MTE. The two selected sites present closed Eh-pH conditions (acidic and oxidant). Nevertheless La Petite Faye site display less leaching than in the site of Enguiales due to its layout: the tailings in the former site are disposed in a settling basin whereas in the latter one, they are spread out on a steep slope. After a chemical and mineralogical characterisation of the tailings, we have estimated according to the Eh-pH conditions the solubilities of the various secondary products. In both sites, the hydrochemical study (for la Petite Faye) and laboratory experiments (for Enguiales) highlight the presence of mineralogical products with low solubility in the current geochemical conditions. At la Petite Faye, scorodite and beudantite mainly ensure an efficient trapping of As and Pb. These two minerals are stable for acidic and oxidant conditions, even if scorodite is more sensitive to pH variations and could transform into goethite. The low As (< 0,1 mg.L-1) and Pb (under detection limit) concentrations measured in the water table along the six-months hydrological study confirm this previous result. In Enguiales, high quantities of As are trapped in amorphous products (Fe/As ~ 1.7). Subsequently As is more easily remobilised and is trapped secondarily by goethite, hematite or jarosite but in few quantities in comparison with those observed in amorphous products (1.4 wt.% < As < 3.5 wt.%). This releasing is highlighted by the leaching experiments, which indicate a significant remobilisation of As issued from amorphous products. However, in current conditions, the properties of the iron oxyhydroxides or of the iron sulphate ensure an efficient As trapping.nnThe different behaviours of the trapping of As and Pb in the two sites are mainly explained by the hydrological context, the tailings layout, their granulometry and the cristallinity of the secondary products.
Comptes Rendus De L Academie Des Sciences Serie Ii Fascicule A-sciences De La Terre Et Des Planetes | 1999
Christophe Roussel; Hubert Bril; Angel Fernandez
Abstract Since large areas have been contaminated by mining activities, knowledge about the evolution of polluted sites and pollutant speciation are required for environmental risk assessment. A mineralogical and chemical investigation was performed on the site of the Chenis mine (France), where sulphide-rich tailings, containing large amounts of arsenic (As), were abandoned in 1944. It revealed that most of S, Fe and As are no longer in sulphide forms in the surface layer (0–2 m). Oxidation products are gypsum, epsomite and As-rich Fe hydroxides. Arsenic fixation was found to be reversible when leaching conditions increase. We also attempted to provide an approach of the As-bearing phases using a normative calculation: average composition is [Fe2O3]5[As2O5]4·30 H2O nearby the reduced original material, and [Fe2O3]3[As2O5]2·18 H2O in more leached material.
Mineralium Deposita | 1986
Eric Marcoux; Hubert Bril
RésuméLes galènes et sulfoantimoniures de plomb des filons quartzeux, barytiques et fluorés du Haut-Allier (district de Brioude-Massiac) ont fait lobjet danalyses isotopiques du plomb. Les résultats montrent lexistence de deux populations de plomb appartenant à chacune des deux phases minéralisatrices reconnues dans la région.La première population (18,108<206Pb/204Pb<18,181) est rapportée à la phase mésothermale permienne. Elle comprend les sulfosels précoces des filons antimonifères ainsi que la galène des filons plombo-stannifères. Lhomogénéité isotopique confirme la liaison génétique existant entre ces différents types filoniens et leur appartenance à un même processus métallogénique. Le socle métamorphique régional apparaît comme la source possible du plomb.La relative dispersion des valeurs isotopiques de la seconde population (18,215<206Pb/204Pb<18,472), dâge liasique, est corrélable avec la situation géographique et géologique des filons. Elle est due à deux phénomènes complémentaires: le lessivage dun segment crustal comprenant le socle métamorphique avec une participation graduée du granite uranifère de la Margeride et la réassimilation partielle du plomb des filons permiens. Ce dernier phénomène dhéritage métallique se traduit au niveau des paragenèses par la formation de filons à sulfosels dominants.AbstractLead isotope analyses are reported for galena and lead sulfosalts from quartz, barite and fluorite vein deposits from the Haut-Allier (Brioude-Massiac district). The data define two lead populations reflecting the two mineralization episodes in this region.The first population (18,108<206Pb/204Pb<18,181) is related to the Permian mesothermal episode. It includes early sulfosalts from antimony veins and galena from lead-stanniferous veins. The Pb isotopic homogeneity confirms the relationship between the different vein types and their formation by a single metallogenic process. The metamorphic basement is the potential source of lead.The second population includes quartz-barite and fluorite veins. It shows much more isotopic variation (18,215<206Pb/204Pb<18,472) correlating with the geographical and geological location of the veins. Because the veins have a contemporaneous age, the isotopic dispersion therefore depends on two complementary phenomena: the leaching of a large volume of crust, including metamorphic basement, with a progressive contribution of the uraniferous granite of Margeride; and the partial remobilization of lead from Permian veins. The latter inheritance phenomena result in the genesis of major lead-sulfosalt vein deposits.
Applied Geochemistry | 2007
C. Néel; M. Soubrand-Colin; A. Piquet-Pissaloux; Hubert Bril
Archive | 1986
Eric Marcoux; Hubert Bril
Archive | 2008
Maxime Vanaecker; P. Vieillard; Alexandra Courtin-Nomade; Hubert Bril
GDR Transmet - Transport, Dépôt et Dispersion Naturelle des Métaux | 2006
Alexandra Courtin-Nomade; Maryline Soubrand-Colin; Andrea L. Foster; Jean-Michel Bény; Frédérique Martin; Maxime Vanaecker; Hubert Bril
3l'Arsenic et ses impacts environnementaux" | 2002
Alexandra Courtin-Nomade; Hubert Bril; Jean-François Lenain; Jean-Michel Bény
ASL - Annales Scientifiques du Limousin | 2001
Hubert Bril; Christophe Roussel; Jean-Pierre Floc'h; Catherine Neel; Alexandra Courtin-Nomade; Jean-Pierre Dutreuil