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- Changing Social Perceptions on Mining-Related Activities: A Key Challenge in the 4th Industrial RevolutionPublication . A., MateusWe are living in a period of multiple and accelerating changes where new uncertainties emerge constantly. Guidelines for economic growth are changing, social demands and environmental concerns are growing, and technological advancements are succeeding at rates never seen before. The main drivers of these changes are mostly related to digitization, decarbonization and dematerialization processes of economies, which follow the recent improvements achieved in biotechnology, digital networks, software design, and information and communication technologies. The ongoing technological (r)evolution includes continued linear progressions of solutions of widespread use along with innovations of exponential increase that will significantly shape the future and have potential to influence the current social and cultural patterns. However, all these transformations stimulate the reliance on a large number of minerals and metals whose increasing demand cannot be fulfilled on the basis of reuse, recycling and/or substitution practices. In other words: the full development of digital, eco-efficient and low-C intensity economies with higher levels of automation will require considerable inputs of raw materials derived from primary resources to balance the demand/supply ratio, filling the gaps of material stocks and flows in the economy that are not provided by secondary sources, even when suitably managed. So, mineral exploration and mining will remain fundamental in the completion of pathways to the future, as occurred throughout the history of human civilization. Notwithstanding this evidence, clearly demonstrated in many studies, the access to mineral resources are becoming increasingly difficult worldwide and mining-related activities are even more perceived negatively by society.
- Current and Foreseen Tungsten Production in Portugal, and the Need of Safeguarding the Access to Relevant Known ResourcesPublication . A., Mateus; Lopes, Catarina; Martins, Luís; GonçalvesThe economic and strategic importance of tungsten is widely recognized, but several concerns exist on its stable future supply. Portugal is one of the main tungsten producers in Europe, having generated ≈121 kt of contained tungsten in mineral concentrates from 1910 to 2020, i.e., ≈3.3% of the global production documented for the same time period. Since the early nineties, tungsten mining in Portugal is confined to the Panasqueira deposit which accounts for 79% of the country reserves (≈5.4 kt). However, according to the performed Generalized Verhulst and Richards curve-fitting forecasts, there is a significant future potential for increasing production in Portugal due to the low (<2%) depletion rates of the remaining known tungsten resources (≈141 kt). This projected growth is not necessarily guaranteed, depending on many unpredictable economic, technological, and political factors, besides appropriate social consents. Even so, a prudent land-use planning oriented to long-term needs should avoid the sterilization of the most relevant tungsten resources so far identified in the country. These are resources of “public importance”, as objectively demonstrated with a weighed multi-dimensional (geological, economic, environmental, and social) approach. Safeguarding the access to these resources does not implicate more than ≈6% of the Portugal mainland territory. The joint interpretation of results independently gathered for tungsten production forecasts and for the definition of areas hosting tungsten resources of public importance, provides additional support to political decisions on the urgent need to reconcile mineral exploration surveys and mining with other land uses.
- Recursos naturais de lítioPublication . A., MateusA necessidade de opções suficientes para armazenamento de energia advém da evolução recente do setor eletroprodutor e tendência veloz para a eletrificação do setor automóvel. A solução tecnológica que hoje se afirma como a mais vantajosa envolve baterias recarregáveis de iões de lítio (LIB) com diferentes configurações, acopláveis em sistemas estacionários de armazenamento de energia e veículos elétricos. Esta solução deverá prevalecer até 2050, competindo com outras alternativas ainda longe de massificação. O fabrico em larga escala de LIB altera drasticamente o padrão de repartição do consumo de lítio nos mercados que abastecem diferentes setores industriais, exercendo forte pressão junto do limitado número de centros de mineração e transformação da matéria- -prima natural no sentido de aumentarem rapidamente o seu ritmo de produção. Esta pressão tenderá a aumentar nos próximos anos a menos que, entretanto, seja possível incrementar de forma satisfatória as taxas de reciclagem das LIB e do lítio; atualmente, os valores das primeiras são insignificantes e menos de 1% do Li consumido é reciclado. As reservas globais conhecidas totalizam ≈15 Mt e estimativas conservadoras posicionam os recursos disponíveis em torno de 53 Mt, embora possam ascender a 62 Mt se boa parte dos recursos inferidos for confirmada. Mantendo-se as taxas de esgotamento anual dos recursos remanescentes registadas nos últimos 5 anos, os picos de exploração serão atingidos a breve trecho, comprometendo muitas das linhas de desenvolvimento tecnológico imaginadas para o futuro, em particular as que se relacionam com a mobilidade eléctrica. Deste modo, a “corrida ao lítio” tem vindo a ganhar expressão crescente, sustentando investimentos significativos em prospecção e pesquisa mineral para melhor caracterizar os recursos existentes e aumentar as reservas globais. Esta é também a razão que explica o recrudescimento dos trabalhos de prospecção em Portugal, um dos grandes produtores de concentrados minerais litiníferos, ocupando desde há muitos anos a 6ª ou 7ª posição do ranking mundial com uma produção média anual de 15800 toneladas entre 1980 e 2016, mas cujo potencial se encontra por avaliar em detalhe.
- Pb-Nd-Sr Isotope Geochemistry of Metapelites from the Iberian Pyrite Belt and Its Relevance to Provenance Analysis and Mineral Exploration SurveysPublication . Luz, Filipa; A., Mateus; Ferreira, Ezequiel; Tassinari, Colombo G.; Figueiras, JorgeThe Iberian Pyrite Belt is a world-class metallogenic district developed at the Devonian-Carboniferous boundary in the Iberian Variscides that currently has seven active mines: Neves Corvo (Cu-Zn-Sn) and Aljustrel (Cu-Zn) in Portugal, and Riotinto (Cu), Las Cruces (Cu), Aguas Teñidas (Cu-Zn-Pb), Sotiel-Coronada (Cu-Zn-Pb), and La Magdalena (Cu-Zn-Pb) in Spain. The Iberian Pyrite Belt massive sulfide ores are usually hosted in the lower sections of the volcano-sedimentary complex (late Famennian to late Visean), but they also occur in the uppermost levels of the phyllite-quartzite group at the Neves Corvo deposit, stratigraphically below the volcano-sedimentary complex. A Pb-Nd-Sr isotope dataset was obtained for 98 Iberian Pyrite Belt metapelite samples (from Givetian to upper Visean), representing several phyllite-quartzite group and volcano-sedimentary complex sections that include the footwall and hanging-wall domains of ore horizons at the Neves Corvo, Aljustrel, and Lousal mines. The combination of whole-rock Nd and Sr isotopes with Th/Sc ratios shows that the siliciclastic components of Iberian Pyrite Belt metapelites are derived from older quartz-feldspathic basement rocks (–11 ≤ εNdinitial ≤ –8 and (87Sr/86Sr)i up to 0.727). The younger volcano-sedimentary complex metapelites (upper Tournaisian) often comprise volcanic-derived constituents with a juvenile isotopic signature, shifting the εNdi up to +0.2. The Pb isotope data confirm that the phyllite-quartzite group and volcano-sedimentary complex successions are crustal reservoirs for metals found in the deposits. In Neves Corvo, where there is more significant Sn- and Cu-rich mineralization, the higher (206Pb/204Pb)i and (207Pb/204Pb)i values displayed by phyllite-quartzite group and lower volcano-sedimentary complex metapelites (up to 15.66 and 18.33, respectively) suggest additional contributions to the metal budget from a deeper and more radiogenic source. The proximity to Iberian Pyrite Belt massive sulfide ore systems hosted in metapelite successions is observed when (207Pb/204Pb)i >15.60 and Fe2O3/TiO2 or (Cu+Zn+Pb)/Sc >10. These are important criteria that should be considered in geochemical exploration surveys designed for the Iberian Pyrite Belt.
- Relative Abundance and Compositional Variation of Silicates, Oxides and Phosphates in the W-Sn-Rich Lodes of the Panasqueira Mine (Portugal): Implications for the Ore-Forming ProcessPublication . A., Mateus; Figueiras, Jorge; Martins, Ivo; Rodrigues, Pedro; Pinto, FilipePanasqueira is a world-class W-Sn-Cu lode-type deposit located in Portugal. It consists of a dense swarm of subhorizontal quartz lodes criss-crossed by several ENE–WSW and N–S fault zones, bordering Late Variscan granite and hosted in Late Ediacaran—Early Cambrian metasediments. The relative abundance and compositional variation (assessed with EPMA) of the main silicates, oxides and phosphates forming the quartz lodes and their margins were examined, aiming to explore: (i) mineral and geochemical zonation at the mine scale; and (ii) some conclusions on the chemical nature of prevalent fluid inflows and T-conditions of mineral deposition. Quartz lodes nearby or far from the known greisen-granite cupola display significant differences, reflecting multiple fluid influxes of somewhat distinct composition related to various opening and closing events extending for several My, ranging from an early “oxide–silicate stage” (OSS) to a “main sulfide stage” (MSS), and further on to a post-ore carbonate stage (POCS); however, a rejuvenation event occurred after MSS. The onset of OSS was placed at ca. 299 ± 5 Ma and the rejuvenation event at ca. 292 Ma. The OSS was confined to ≈500 ≤ T ≤ 320 °C, following rutile and tourmaline growth under ≈640 ≤ T ≤ 540 °C (depending on aSiO2). The rejuvenation event (≈440–450 °C) preceded a late chlorite growth (≈250–270 °C) and the progression towards POCS.