2,837 research outputs found
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
Examining strategies behind universities’ technology transfer portfolio: how different patterns of resource consumption can lead to similar technology transfer profiles
Purpose – This research analyses how different patterns of production factors consumption of Spanish universities lead to specific technology transfer (TT) profiles (outcomes). Design/methodology/approach – Adopting a resource-based view perspective (RBV), qualitative comparative analysis (QCA) is used to analyse the relationship between different combinations of resources—human resources, financial resources and support services—and various portfolios of TT outcomes—intellectual or industrial property agreements, spin-offs and TT income. Findings – Results indicate that there is no unique formula of resource consumption that leads to a specific portfolio of TT outcomes. These results seem to reflect the characteristics and competences added by universities, along with the characteristics of their socioeconomic context. From a RVB perspective, this indicates that the considered resources are substitutable. Practical implications – The effectiveness of university policies is expected to vary by university, e.g. depending on the type of resources that is most relevant in the university’s production process. To develop competitive advantages Spanish public universities must resort to internal intangible resources or specific and inimitable combinations of the available resources. Social implications – Since Spanish universities are heterogeneous and display different TT portfolios they address the needs of different users. Originality/value – Previous studies have failed to acknowledge the heterogeneity among universities. To perform our analysis we employed QCA, an innovative methodology in the higher education sector that enables us to purposefully acknowledge institutional diversity (in both resources and results). This allows us to indirectly take into account the capabilities of universities using a more holistic approach to evaluate their competitiveness.Peer ReviewedPostprint (published version
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
Metals and arsenic enrichment processes in sulfide-rich waste dumps - the role of the clay size fraction
[Extract] 1. Purpose
Abandoned mines pose some of the most outstanding environmental risks, namely related
with potentially toxic metals and metalloids in mining soils. Mobilization or fixation of these
elements in the soil particles can be regulated by the interactions between several biogeochemical
and mineralogical processes. In this context, the present study is focused on the detection of metals
and arsenic enrichment processes in different particle size fractions of two distinctive sulphide-rich
waste dumps. Furthermore, the study evaluates the role of typical clay size minerals, such as
oxyhydroxides and clay minerals in the retention of toxic elements...info:eu-repo/semantics/publishedVersio
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
ABIETANE DITERPENOIDS FROM PLECTRANTHUS GRANDIDENTATUS
The acetone extract of the whole plant of Plectranthus grandidentatus provided the already known
abietanes royleanone, 6,7-dehydroroyleanone, horminone, 6β-hydroxyroyleanone, 7α-acetoxy-6β-hydroxyroyleanone and the abietane dimers grandidone C, grandidone D and 7-epigrandidone D, together with a mixture of
fatty acid esters of 7α-acyloxy-6β,12-dihydroxy-abieta-8,12-diene-11,14-dione. Some of these compounds showed
moderate antibacterial activity
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
Evaluation of dilution processes in streams affected by acid mine drainage in the Iberian Pyrite Belt
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-
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