6 research outputs found
Les rejets miniers de traitement : caractérisation, capacité polluante et impacts environnementaux, mine Zeïda, mine Mibladen, Haute Moulouya (Maroc)
No full textThe aim of this study is to characterize the wastes of treatment abandoned at the mine sites Zeida and Mibladen (Upper Moulouya, eastern of Morocco).highlight the polluting capacity of these wastes and determine their environmental impacts taking into account climate semi-arid and geological context carbonate and silicate in the region. The results showed that the mining wastes at Zeida (RZ) and at Mibladen (RM) consist of fine particle size, have low geotechnical stability, highly mobile and exhibit high levels of toxic trace metals (MTE) (Pb: 5547ppm for RZ//10520ppm for RM). These wastes with alkaline pH are affected by intense water erosion and in particular wind erosion and they create multiple environmental impacts. lndeed, in addition to the negative impact on the landscape that they generate, MTE contained in these wastes are transported, spread and contaminate surface water resources and soil around: (water: Pb: 13-430g/1//Sediments Pb:33-2415ppm //Soils: Pb:71-566 ppm). However, we note that the risk of contamination related to chemical weathering from the studied wastes is reduced sequel on the one hand to the Jack of moisture in semi-arid climate favoring chemical reactions within the waste and second/y due to the abundance of carbonates and 1 or silicates in wastes and into the geological terrain of the region. Phenomena of acid mine drainage (AMD), in particular acidification of surface water and leachate, most remarkable phenomenon of AMD were detected anywhere in mining districts. This is the contaminated neutral drainage (CND) for mining wastes of Zeïda and Mibladen at upper Moulouya. Mechanical wind erosion is the main vector of the dispersion of suspended particles of contaminants from wastes studied.L'objectif de cette étude est de caractériser les rejets miniers de traitement abandonnés aux centres miniers Zeïda et Mibladen (Haute Moulouya, oriental du Maroc), de mettre en exergue la capacité polluante de ces rejets et déterminer leurs impacts environnementaux tenant compte du climat semi-aride et du contexte géologique dans la région. Les résultats ont révélé que les verses à rejets miniers à Zeïda (RZ) et à Mibladen (RM) sont constituées de particules de taille fine, de stabilité géotechnique faible, très mobiles et présentent des teneurs élevées en éléments traces métalliques toxiques (ETM) (Pb : 5547ppm pour RZ//10520ppm pour RM).Ces rejets à pH alcalin (8,4) subissent l'effet d'une intense érosion hydrique et en particulier éolienne et créent de multiples impacts environnementaux. En effet, en plus de l'impact paysager négatif qu'ils génèrent, les ETM contenus dans ces rejets sont transportés, disséminés et contaminent les ressources en eaux de surface et les sols aux alentours : (Eaux : Pb : 13-430µg/l//Sédiments : Pb : 33-2415ppm//Sols : Pb : 71-566 ppm). Toutefois, on note que le risque de contamination lié à l'altération chimique à partir des rejets miniers étudiés est réduit suite d'une part au manque d'humidité en climat semi aride favorisant les réactions chimiques au sein des rejets et d'autre part suite à l'abondance des carbonates et/ou des silicates dans les rejets et dans les terrains géologiques de la région. Les phénomènes du drainage minier acide (DMA), en particulier l'acidification des eaux de surface et des lixiviats, phénomène le plus remarquable du DMA n'ont été décelés nulle part au niveau des districts miniers. Il s'agit du drainage neutre contaminé (DNC) pour les rejets des mines Zeïda et Mibladen de la Haute Moulouya. L'érosion mécanique éolienne est le vecteur principal de la dispersion, à partir des rejets miniers étudiés, de particules en suspension contaminants
Pollution and ecological risk assessment of heavy metals in the soil-plant system and the sediment-water column around a former Pb/Zn-mining area in NE Morocco
No full textInternational audienceThis study discussed the environmental fate and ecological hazards of heavy metals in the soil-plant system and sediment-water column around the former Pb-Zn mining Zelda district, in Northeastern Morocco. Spatial distribution, pollution indices, and cluster analysis were applied for assessing Pb, Zn, As, Cu and Cd pollution levels and risks. The geo-accumulation index (I-geo.) was determined using two different geochemical backgrounds: i) the commonly used upper crust values, ii) local geochemical background calculated with exploratory data analysis. The soils in the vicinity of the tailings, as well as the sediments downstream of the latter, displayed much higher metal concentrations, Igeo, and potential ecology risk coefficient values than other sites, classifying these sites as highly contaminated and severely hazardous. The concentrations of Pb in contaminated sediment samples also exceeded the PEC limits and are expected to cause harmful effects on sediment-dwelling organisms. Based on the comparison with the toxicity limits, the most contaminated plant samples were found around the tailings piles. The metal concentrations in both raw and filtrated water samples were overall below the drinking water standards in samples upstream and downstream of the mining center, indicating that heavy metals levels in the Moulouya River surface waters were not affected by the tailings spill. Cluster analysis suggest that: i) Pb and Zn in sediments were derived from the abandoned tailings and are mainly stored and transported as particle bound to the bedload, ii) Pb, Zn, and Cu in the soil-plant system were related to the dispersion of tailings materials while As and Cd originated primarily from natural geological background in both the soil-plant and the water-sediment systems
The canary in the mine: Mediterranean mines as indicators of the hold on territories and resources: French Pyrenees, Moroccan Middle Atlas, and Tunisian coastal mountains
No full textInternational audienceMediterranean mountains have been and continue to be used by human populations along an interweaving of numerous uses: agro-sylvo-pastoralism, trade, industry and mining have all gone hand in hand for several millennia. Mines are however a so important source of wealth that, by putting in contact external powers and mountain locals, it creates an imbalance of powers inducing structural violence and tensions. The 1830–1962 colonial era did change the magnitude of these imbalances and this affect all Mediterranean mountainous ranges. The French expansion did affect as a result the Moroccan Atlas, the Tunisia Coastal Mounts but also the French Pyrenees. The article explores the available archives regarding the history of three mines in each of these emblematic mountains with a shared mining and agro-sylvo-pastoral past and where mining were actually well-known: Sem-Rancié and Puymorens in the French Pyrenees, Mibladen and Zeïda in the Moroccan Middle Atlas and Jebel Ressass in Tunisia. These reconstructions show that the initial social and political situations, as diverse as they are, are of little importance in the trajectory of these mines: all of them see a rapid appropriation by economic powers that are more and more powerful and more and more distant as far as Paris, the common capital in colonial times, despite several revolts and tensions. The initial expansion then gave way to a structural crisis due to the competition with other mining sites until abandonment. The following powers, post-colonial in Morocco or Tunisia or decentralized in France, did not endorse any responsibility of this the post-mining environmental, social and economic legacy. For each of these sites, the mine could be seen as an indicator of the power balance evolution among activities and actors, a canary in the mine on which we propose a methodology for further investigations
The canary in the mine: Mediterranean mines as indicators of the hold on territories and resources: French Pyrenees, Moroccan Middle Atlas, and Tunisian coastal mountains
No full textInternational audienceMediterranean mountains have been and continue to be used by human populations along an interweaving of numerous uses: agro-sylvo-pastoralism, trade, industry and mining have all gone hand in hand for several millennia. Mines are however a so important source of wealth that, by putting in contact external powers and mountain locals, it creates an imbalance of powers inducing structural violence and tensions. The 1830–1962 colonial era did change the magnitude of these imbalances and this affect all Mediterranean mountainous ranges. The French expansion did affect as a result the Moroccan Atlas, the Tunisia Coastal Mounts but also the French Pyrenees. The article explores the available archives regarding the history of three mines in each of these emblematic mountains with a shared mining and agro-sylvo-pastoral past and where mining were actually well-known: Sem-Rancié and Puymorens in the French Pyrenees, Mibladen and Zeïda in the Moroccan Middle Atlas and Jebel Ressass in Tunisia. These reconstructions show that the initial social and political situations, as diverse as they are, are of little importance in the trajectory of these mines: all of them see a rapid appropriation by economic powers that are more and more powerful and more and more distant as far as Paris, the common capital in colonial times, despite several revolts and tensions. The initial expansion then gave way to a structural crisis due to the competition with other mining sites until abandonment. The following powers, post-colonial in Morocco or Tunisia or decentralized in France, did not endorse any responsibility of this the post-mining environmental, social and economic legacy. For each of these sites, the mine could be seen as an indicator of the power balance evolution among activities and actors, a canary in the mine on which we propose a methodology for further investigations
