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- Um novo método de prospeção geoquímica para a identificação de depósitos profundos do tipo VMS. Aplicação ao depósito de Cu-Zn de Neves-Corvo, Faixa Piritosa IbéricaPublication . Morais, Igor; Rosado, L.; Albardeiro, Luís; Mirao, Jose; Batista, Maria Joao; Matos, João XavierSUMMARY: The fast energetic transition in the world needs large amounts of mineral resources that are currently scarce. For the suppression of these needs, new mineral deposits must be found, demanding the development of new exploration techniques. Currently, in several metalogenetic provinces, surface deposits are rare. In the Iberian Pyrite Belt, geophysical techniques, namely gravimetry and electromagnetics, have been used over the last years leading to the discovery of several hiden Volcanogenic Massive Sulphide deposits (VMS). Therefore, it is proposed a new geochemical technique that, through the chemical analysis of rock coatings, can lead to the identification of mineral deposits located at greath depth. The method is represented by the European Patent EXPLORA – LNEG/Évora University-Hércules Laboratory.
- Abandoned mine slags analysis by EPMA WDS x-ray mappingPublication . Guimarães, Fernanda; Rosado, L.; Morais, C.; Candeias, A. E.; Pinto, A. P.; Mirao, JoseThe mining activity on the Iberian pyritic Belt (Portugal and Spain) started before Phoenician times, became particularly intense during the Roman occupation of the Iberian Peninsula (for gold) and after the industrial revolution (for gold, copper, zinc, lead and sulphur). The commonest ore of this region is a massive polymetalic sulphide accumulation, where pyrite (FeS2) is the main mineral, with variable concentrations of chalcopyrite (CuFeS2), sphalerite (ZnS), galena (PbS), arsenopyrite (FeAsS2), other sulphides and sulfosalts which include minor elements like Mn, Co, Ni, Se, Cd, Sb, Te, Hg and Bi. Some of the main and minor elements of these ores are hazardous and the drainage basins of pollutant source areas often induce health concerns in the resident population. Electron microprobe study followed previous optical and XRD analysis of the slags. The study focused on the identification of phases how sulphide and meta11ic phases are distributed within the material and infer about leachable elements during weathering. Electron microprobe X-Ray maps show evidences of different behavior between the elements: Ca and Zn are completely leached; iron is retained in oxyhydroxides, lead and arsenic precipitate as sulphates. Electron microprobe studies are essential to understand complex materials as earth materials. Nevertheless, care is required to a correct interpretation of data and most quantitative compositional data are not trustworthy.