The Portuguese São Domingos mine is located in the Iberian Pyrite Belt along with other mines located on the Spanish side, such as Río Tinto or Almagrera, Huelva. The mine abounds in highly contaminating waste, such as smelting dregs and ash. Active between 1857 and 1966, over time it has generated "extremely" acidic drainage due to the oxidation of sulfuric waste.
According to Antonio M. Álvarez-Valero, lead author of the study published recently in the journal Environmental Geology and currently a researcher at the Andalusian Institute of Earth Sciences (a University of Granada - CSIC joint center), "the fundamental concern from the environmental point of view deriving from this waste oxidation is the generation of acidic waters".
And the acidic discharge from São Domingos affects Chanza dam, the largest drinking water reservoir serving Huelva, because the pollutants undergo "a relative attenuation".
To evaluate the environmental impact and determine the level of acidification of some components, the study presents a characterization of the mineralogical, geochemical and physical properties of the mining waste from the São Domingos district. "We have established, through a later work, the potential risk of moving the toxic metals in this waste, and their possible incorporation into the food chain", Álvarez-Valero explains to SINC.
Although the mine is abandoned, it remains active "from the point of view of contamination". The researcher says that the contaminating impact of the mine is renewed in annual cycles. During the wet or raining periods, the contaminating elements "re-dissolve and once again generate acidity", Álvarez-Valero points out.
The analysis shows that "the massive presence of sulfurs in São Domingos in some of the waste ensures a continuous, annual generation of acidic mine drainage", the researcher confirms.
The mine, which is considered medium in size compared to others, is exposed to "a remarkable" volume of waste: 25 Mm3. Although a large part of this waste is inaccessible because it is located beneath the town of São Domingos, "its high acidification potential represents a threat for environmental pollution", the scientist says.
Faced with this situation, the researchers say that the methodical sequence of this study should be applied to other mines in the same area, such as Caveira, Lousal, Aljustrel, in the south-east of Portugal, and Tharsis, La Zarza, Peña del Hierro, Almagrera or Río Tinto, in Huelva, where research projects are already underway.
The São Domingos mining district was active between the 19th and 20th centuries, but "mining there goes back to pre-Roman times", says Álvarez-Valero. In the abandoned or fossil mining areas, the largest sources of soil and surface water contamination come from the leaching (washing) of metals and metalloids from waste rich in sulfur (such as pyrite).
SINC Team | alfa
Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen
A new indicator for marine ecosystem changes: the diatom/dinoflagellate index
21.08.2017 | Leibniz-Institut für Ostseeforschung Warnemünde
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...
Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...
Scientists from the MPI for Chemical Energy Conversion report in the first issue of the new journal JOULE.
Cell Press has just released the first issue of Joule, a new journal dedicated to sustainable energy research. In this issue James Birrell, Olaf Rüdiger,...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
19.09.2017 | Event News
19.09.2017 | Physics and Astronomy
19.09.2017 | Power and Electrical Engineering