Magnesium and aluminum sulfates in salt efflorescences from acid mine drainage in the Iberian Pyrite Belt (SW Spain)

Proceedings IMWA 2016, Freiberg/Germany | Drebenstedt, Carsten, Paul, Michael (eds.) | Mining Meets Water – Conflicts and Solutions.The current study is focused on AMD-precipitates that compose the typical magnesium and aluminum sulfate assemblages in the Spanish sector of the Iberian Pyrite Belt (SW Spain). The main objectives are identify and describe the composition, morphology and paragenetic relationships of these sulfate phases. From the methodological pint of view, sampling procedure covered the entire metallogenetic province, including five selected representative mines and eight river basins, which are the main receptors of the acid mine drainage discharges. The mineralogical analyses were performed by X-Ray diffraction and electron microscopy. The obtained results showed the extraordinary abundance of aluminum sulfates with acicular habit, from the series pickeringite-apjhonite-halotrichite. They form typical assemblages with other aluminum sulfates, such as alunogen and tamarugite, and with the Mg sulfates: epsomite and hexahydrite. Moreover, the paragenetic relationships indicate the late occurrence of acicular Alsulfates from the halotrichite group.Financial support for this research was provided by the Andalusian Autonomous Government Excellence Project, code P06-RNM-02167. This work was also co-funded by the European Union through the European Regional Development Fund, based on COMPETE 2020 (Programa Operacional da Competitividade e Internacionalização), project ICT (UID/GEO/04683/2013) with reference POCI-01-0145-FEDER-007690 and national funds provided by Fundação para a Ciência e Tecnologia.info:eu-repo/semantics/publishedVersio

Ocorrência de eflorescências sulfatadas na mina de São Domingos

The intense exploration of sulphide ore deposit in São Domingos mine, produced considerable amount of sulphide material that when are exposed to weathering generates acid mine drainage (AMD). The main goal of this paper is to study a specific occurrence regarding composition and morphology of the salts that arise at the end of the dry season. Soluble salts appear at the banks of the drainage channels and over the waste materials, exhibiting different colours and aspects. The obtained results showed by X-Ray diffraction and scanning electronic microscopy, that the mineralogy of salt efflorescences is dominated by sulphates, displaying different occurrence modes. Melanterite and copiapite are the main iron sulphates while minerals from the series of pickeringite-halotrichite dominate the aluminium sulphates. In addition, dehydration and dissolution laboratory experiments were carried out in order to simulate the transformations suffered by soluble salts and evaluate the environmental effect in aquatic system.Patrícia Gomes wishes to acknowledge FCT (Science and Technology Foundation, Portugal) by the research fellowship under the POCH (Programa Operacional Capital Humano) supported by the European Social Fund and National Funds of MCTES with reference SFRH/BD/108887/2015. This work was co-funded by the European Union through the European Regional Development Fund, based on COMPETE 2020 (Programa Operacional da Competitividade e Internacionalização), project ICT (UID/GEO/04683/2013) with reference POCI-01-0145-FEDER-007690 and national funds provided by FCT (Science and Technology Foundation, Portugal)

Acid mine drainage in semi-arid regions: the extent of the problem in the waters of reservoirs in the Iberian Pyrite Belt (SW Spain)

There are many reservoirs in the Iberian Pyrite Belt (IPB), SW Spain, which receive contributions from watercourses affected by acid mine drainage processes, characterised by low pH values and high concentrations of heavy metals and sulphates. When they reach the reservoirs, the waters increase its pH, which will cause most of the metal load carried by the mining channel to precipitate into the reservoir itself and accumulate on its floor. The silting of reservoirs is an environmental problem which can affect the loss of storage capacity, their general functioning and aquatic ecosystems. A study of these is vital to allow both preventative and corrective measures to be established. Climatic conditions are the most significant external controlling factors in terms of the degree and type of mining pollution. The study area presents characteristics typical of the semi-arid Mediterranean climate, with annual precipitation of around 630 mm/year; moderate temperatures with average annual values of 17.1 W C and a temperature range of 50 W C. The aim of this study is to carry out a physical–chemical characterization of the waters where they enter the reservoirs located in the IPB over the course of a hydrological year and to establish possible interdependencies between the various parameters.Financial support for this research was provided by DGCICYT National Plan, project no. CGL2010-21268-C02-01.info:eu-repo/semantics/publishedVersio

Efficacy of sonic and ultrasonic irrigation devices in the removal of debris from canal irregularities in artificial root canals

Objective: To evaluate the efficacy of different sonic and ultrasonic devices in the elimination of debris from canal irregularities in artificial root canals. Materials and Methods: A resin model of a transparent radicular canal filled with dentin debris was used. Five groups were tested, namely: Group 1 – ultrasonic insert 15.02; Group 2 – ultrasonic insert 25/25 IRRI K; Group 3 – ultrasonic insert 25/25 IRRI S; Group 4 – sonic insert 20/28 Eddy on a vibrating sonic air-scaler handpiece; Group 5 – 20.02 K-file inserted on a Safety M4 handpiece. Two different irrigants (5% sodium hypochlorite and 17% EDTA) and 3 different times of activation (20, 40, and 60 seconds) were tested. Means and standard deviations were calculated and statistically analyzed with the Kruskal-Wallis and Wilcoxon tests (p<0.05). Results: No statistically significant differences were found between the two irrigants used. Group 4 removed more debris than the other groups (p<0.05). Groups 1, 2, and 3 removed more debris than group 5 (p<0.05). A statistically significant difference (p<0.05) was found for the time of activation in all groups and at all canal levels, except between 40 and 60 seconds in group 4 at coronal and middle third level (p>0.05). Conclusions: No significant differences were found between 5% sodium hypochlorite and 17% EDTA. When the time of activation rises, the dentin debris removal increases in all groups. Both sonic and ultrasonic activation demonstrate high capacity for dentin debris removal

Indicators of acid mine drainage in an affected system: the case of the mine Santo António de Penedono

O presente estudo descreve os efeitos da evolução geoquímica e mineralógica dos resíduos mineiros acumulados na escombreira de Santo António de Penedono, Penedono. Mediante a aplicação de diferentes tipos de indicadores: físico-químicos, ecológicos e mineralógicos, descrevem-se as propriedades do ambiente de drenagem superficial. Os resultados demonstram o caráter ácido do efluente e sugerem a eficácia de algas acidófilas como indicadoras de contaminação mineira. A análise mineralógica põe em evidência o papel dos precipitados de drenagem ácida no controle da mobilidade de poluentes, em especial do arsénio.The present study describes the effects of geochemical and mineralogical evolution of Penedono mine waste-dumps by applying different types of indicators: physical-chemical, ecological and mineralogical. The results obtained demonstrated the typical sulfated nature of acid mine drainage (AMD) and suggested the effectiveness of acidophilic algae as indicators of mining pollution. Mineralogical analysis by X-ray diffraction and transmission electron microscopy highlights the role of AMD-precipitates controlling the mobility of pollutants, in particular of arsenic.(undefined

Mineralogical controls on mobility of rare earth elements in acid mine drainage environments

Supplementary data related to this article can be found at https://doi.org/10.1016/j.chemosphere.2018.04.095.Rare earth elements (REE) were analyzed in river waters, acid mine waters, and extracts of secondary precipitates collected in the Iberian Pyrite Belt. The obtained concentrations of the REE in river water and mine waters (acid mine drainage - AMD) were in the range of 0.57 μg/L (Lu) and 2579 μg/L (Ce), which is higher than previously reported in surface waters from the Iberian Pyrite Belt, but are comparable with previous findings from AMD worldwide. Total REE concentrations in river waters were ranged between 297 μg/L (Cobica River) and 7032 μg/L (Trimpancho River) with an average of 2468 μg/L. NASC (North American Shale Composite) normalized REE patterns for river and acid mine waters show clear convex curvatures in middle-REE (MREE) with respect to light- and heavy-REE. During the dissolution experiments of AMD-precipitates, heavy-REE and middle-REE generate the most enriched patterns in the solution. A small number of precipitates did not display MREE enrichment (an index Gdn/Lun < 1.0) in NASC normalized pattern and produced relatively lower REE concentrations in extracts. Additionally, very few samples, which mainly contained aluminum sulfates, e.g., pickeringite and alunogen, displayed light-REE enrichment relative to heavy-REE (HREE). In general, the highest retention of REE occurs in samples enriched in magnesium (epsomite or hexahydrite) and aluminum sulfates, mainly pickeringite.Financial support was provided by the Andalusian Autonomous Government Excellence Project, code P06-RNM-02167. This work was also co-funded by the European Union through the European Regional Development Fund, based on COMPETE 2020, project ICT (UID/GEO/04683/2013), reference POCI-01-0145-FEDER-007690, national funds provided by FCT. Post-Doctoral Fellowship through Erasmus Mundus SAT program and Young Scientist Research Grant (SEAS-2015−14) of the National University of Mongolia were supported for T.-O. Soyol-Erdene. The authors also appreciate the valuable comments and suggestions made by the anonymous reviewers

Efficacy of sonic and ultrasonic irrigation devices in the removal of debris from root canal irregularities in artificial root canals

Objective: to evaluate the efficacy of different sonic and ultrasonic devices in the elimination of debris from canal irregularities in artificial root canals. Materials and Methods: a resin model of a transparent radicular canal filled with dentin debris was used. Five groups were tested, namely: Group 1 - ultrasonic insert 15.02; Group 2 - ultrasonic insert 25/25 IRRI K; Group 3 - ultrasonic insert 25/25 IRRI S; Group 4 - sonic insert 20/28 Eddy on a vibrating sonic air-scaler handpiece; Group 5 - 20.02 K-file inserted on a Safety M4 handpiece. Two different irrigants (5% sodium hypochlorite and 17% EDTA) and 3 different times of activation (20, 40, and 60 seconds) were tested. Means and standard deviations were calculated and statistically analyzed with the Kruskal-Wallis and Wilcoxon tests (p0.05). Conclusions: no significant differences were found between 5% sodium hypochlorite and 17% EDTA. When the time of activation rises, the dentin debris removal increases in all groups. Both sonic and ultrasonic activation demonstrate high capacity for dentin debris removal

Spatial behavior of acid mine drainage in a peculiar stream : physical-chemical evolution from the source until the temporarlly receptor in the Iberian Pyrite Belt

Publicado em "Proceedings of the Energy and Environment Knowledge Week 2014 (E2KW2014), ISBN 978-84-697-1162-0"The Iberian Pyrite Belt is a vast concentration of massive sulphide, located in the SW of the Iberian Peninsula. Historically, this area has undergone an intense mining activity, which has left a huge amount of mining facilities and unrestored waste dumps. Mineral-water interaction in the waste dumps is responsible for the generation of acid mine drainage (AMD), causing a strong impact in the water systems. The AMD occurs when the sulfide minerals are in the presence of atmospheric oxygen and humidity, suffering oxidation reactions. As a consequence, metals and acidity are mobilized into the receiving watercourses. Such conditions have created a unique scenario in the world by the extreme degradation that characterizes the network of channels and streams in the IPB. In this context, widely described in the scientific literature, the present study aims to monitoring a singular channel affected by AMD (Campanario stream), from its origin (in the waste dump) to its confluence with an unpolluted stream. Such monitoring procedure will allow characterizing the physicochemical evolution and the mineral-water processes that regulate it

Four abandoned mines, one acid mine drainage affected river and an unsolved issue for a water supply reservoir

Publicado em "Proceedings of the Energy and Environment Knowledge Week 2014(E2KW2014)". ISBN 978-84-697-1162-