Mineralogy and geochemistry of a clogged mining reservoir affected by historical acid mine drainage in an abandoned mining area
| Autor: | Patrícia Gomes, M. A. Sequeira Braga, M. L. de la Torre, Jose Antonio Grande, Teresa Maria Fernandes Valente, José Borrego, M. Santisteban |
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| Přispěvatelé: | Universidade do Minho |
| Rok vydání: | 2015 |
| Předmět: |
Ciências Naturais::Ciências da Terra e do Ambiente
Science & Technology SW Spain Metal(oids) Mineralogy Acid mine drainage 6. Clean water Clay minerals 13. Climate action Geochemistry and Petrology Clogged reservoir Riotinto Economic Geology Jarosite National budget Ciências da Terra e do Ambiente [Ciências Naturais] Geology |
| Zdroj: | Repositório Científico de Acesso Aberto de Portugal Repositório Científico de Acesso Aberto de Portugal (RCAAP) instacron:RCAAP |
| ISSN: | 0375-6742 |
| DOI: | 10.1016/j.gexplo.2015.05.016 |
| Popis: | The present study is focused on a water reservoir that is under the influence of AMD in the historic mining area of Riotinto (SW Spain). Transport of particulate matter and chemical precipitation within the reservoir has caused its clogging. Hydrochemical, geochemical and mineralogical characterization allowed to assess the degree of contamination by trace elements. The results indicate high average concentrations of metals and metalloids in water and sediments. The sediments are strongly enriched in As, Pb, Cu, and Zn, which occur with concentrations > 1000 mg/kg. Highest accumulation was observed for As and Pb, which gave enrichment factors in the range 358–471, indicative of extreme pollution. Geochemical trends show strong correlation between major elements, including Fe and Al, mobilized from the source material. Mineralogy of the clogging material showed a short-range of spatial variability. Among the newly formed phases jarosite and goethite are the most abundant. They are especially concentrated in the clay size fraction. Combining results about chemistry of the sediments and mineral distribution suggests that As is being retained by both clay and iron-rich minerals. Furthermore, results indicate that jarosite forms directly from sulphide oxidation, whereas goethite may result from transformations undergone in the reservoir. Financial support for this research was provided by DGCICYT National Plan, project CGL2010-21268-C02-01. CIG-R is supported by the national budget of the Portuguese Republic through FCT — under the project PEst-OE/CTE/UI0697/2011. The authors thank to António Azevedo for his help in XRD analysis and to Elisabete Vivas for her assistance with the preparation of clay fraction. Also, the authors are grateful to Dr Irwan Iskandar and to an anonymous reviewer for their valuable contributions for the manuscript. info:eu-repo/semantics/publishedVersion |
| Databáze: | OpenAIRE |
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