Browsing by Issue Date, starting with "2021-05"
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- Map of Cobalt, graphite, lithium deposits (including deposits where cobalt is a significant by product : DELIVERABLE D5.4Publication . Gautneb, Håvard; Gloaguen, Eric; Törmänen, Tuomo; Pereira, Aurete; Sadeghi, MartiyaABSTRACT: The deliverable D5.4 “Map of Cobalt, graphite, lithium deposits (including deposits where cobalt is a significant by product”, is a technical report for a product where the actual deliverable is a web map and associated data. A description of the data collection, interpretation, description of the geology, metallogeny and resource potential is reported and described in the deliverable D5.3.
- Innovative seismic imaging of volcanogenic massive sulfide deposits, Neves-Corvo, Portugal — Part 1: In-mine arrayPublication . Brodic, Bojan; MALEHMIR, Alireza; Pacheco, Nelson Bruno Monteiro; Juhlin, Christopher; Carvalho, João; Dynesius, Lars; Van Den Berg, Jens; de Kunder, Richard; Donoso, George; Sjölund, Tord; Araújo, VítorABSTRACT: To evaluate and upscale the feasibility of using exploration tunnels in an operating mine for active-source seismic imaging, a seismic experiment was conducted at the Neves-Corvo mine, in southern Portugal. Four seismic profiles were deployed in exploration drifts approximately 650 m beneath the ground surface, above the world-class Lombador volcanogenic massive sulfide deposit. In addition to the tunnel profiles, two perpendicular surface seismic profiles were deployed above the exploration tunnels. The survey was possible due to a newly developed prototype global positioning system (GPS) time transmitter enabling accurate GPS synchronization of cabled and nodal seismic recorders, below and on the surface. Another innovative acquisition aspect was a 1.65 t broadband, linear synchronous motor (LSM) driven — electric seismic vibrator (e-vib) used as the seismic source along two of the exploration tunnels. We have evaluated the challenges and innovations necessary for active-source tunnel seismic acquisition, characterized by high levels of vibrational noise from the mining activities. In addition, we evaluated the LSM vibrator’s signal and overall seismic-data quality in this hard rock mining environment. Our processing results from the tunnel data and 3D reflection imaging of the Lombador deposit below the exploration tunnels were checked for consistency through constant-velocity 3D ray-tracing traveltime forward modeling. For imaging purposes, 3D Kirchhoff prestack depth and poststack time-migration algorithms were used, with both successfully imaging the targeted deposit. The results obtained show that active-source-seismic imaging using subsurface mining infrastructure of operational mines is possible. However, it requires innovative exploration strategies, a broadband seismic source, an accurate GPS-time system capable of transmitting GPS-time hundreds of meters below the surface, and careful processing. The results obtained open up possibilities for similar studies in different mining or tunneling projects.
- Metal(loids) bioaccessibility in road dust from the surrounding villages of an active minePublication . Candeias, Carla; Ávila, Paula Freire; Silva, Ferreira Da; Rocha, FernandoABSTRACT: Human activities, in general, cause a significant impact on the environment and human health. The present study aims to characterize the road dust of villages located near an active mine and to assess metal(loids) bioaccessible fractions. From the collected road dust samples (<250 µm fraction), the pseudo total, gastric (G) and gastrointestinal (GI) phase (UBM assay) concentrations, mineralogical composition, enrichment factor (EF), and risk for humans were determined. The obtained results revealed that arsenic represents the highest risk to humans, with mean pseudototal values higher than the maximum reference value range. The enrichment factor pointed to As as having significant to very high enrichment in all of the villages. In addition, Cd presented the maximum EF values in all of the villages, and was thus classified as having a very high enrichment. Particles enriched in As, Ca, Fe, Cu, Al, and Ti were identified by SEM-EDS in weathered agglomerates, and were linked to mine wastes and long-distance transport through both wind and/or traffic. The arsenic bioaccessibility fraction (%BAF) presented low values in the studied samples, possibly because of the low complex solubility of Fe with adsorbed As, limiting the release of arsenic and reducing its bioaccessibility. The concentrations of bioaccessible Cd for the G and GI phases were within the reference range, while for Cu, they were above and for Pb they were lower than the reference value range. The results show that the pseudototal fraction risk is overestimated when compared with BAF%; nevertheless, the total G and GI risks were above the carcinogenic target risk (1 × 10−6) in most of the samples. The carcinogenic risk of the bioaccessible contaminants showed that As represented the higher risk for developing cancer over a lifetime, with ingestion being the main risk route.
- Innovative seismic imaging of volcanogenic massive sulfide deposits, Neves-Corvo, Portugal — Part 2: Surface arrayPublication . Donoso, George; MALEHMIR, Alireza; Brodic, Bojan; Pacheco, Nelson Bruno Monteiro; Carvalho, João; Araújo, VítorABSTRACT: Seismic methods are an affordable and effective way of studying the subsurface for mineral exploration. With the goal of testing new technologies for mineral exploration in highly challenging mining areas, in early 2019, an innovative seismic survey was conducted at the Neves-Corvo mine, south Portugal. We have focused on the data and results from the surface array data, whereas other work deals with the underground seismic data. The surface seismic survey consisted of two perpendicular 2D profiles positioned above the known world-class tier-1 Lombador deposit. Simultaneously, a survey inside the active underground mine took place, being unique because it included the testing of a prototype system that enabled accurate GPS-time (microsecond accuracy) synchronization inside the mine tunnels, approximately 650 m below the surface profiles. Due to the active mining operations, the surface data are noisy. To handle this, a carefully tailored processing algorithm was developed and applied to enhance reflections in the data, interpreted to originate from lithologic contacts and the Lombador deposit. The results and interpretations from 2D processing were validated taking advantage of the known deposit geometry using 3D exploding reflector modeling and pseudo-3D cross-dip analysis. These analyses suggest that there is an out-of-plane signature of the Lombador deposit on the surface data. Additionally, source points activated in the exploration tunnels and simultaneously recorded on the surface profiles allowed for the creation of a 2D velocity model that was used for migration and time-to-depth conversion, providing a reliable 2D seismic section of the subsurface under the surface profiles. We determine that limited surface coverage 2D surveys and a velocity model derived from the tunnel-to-surface seismic recordings allow for imaging of key subsurface geologic structures and delineating mineral deposits of economic interest.
- Optoelectronic Study of Perovskites/SnO2 based Metal-Insulator-Semiconductor Structures [Poster]Publication . Cunha, J.M.V.; Barreiros, M. Alexandra; Curado, M.A.; Lopes, T.S.; Oliveira, K.; Oliveira, A.J.N.; Vinhais, C.; Flandre, Denis; Teixeira, J.P.; Silva, Ana G.; Fernandes, P.A.; Salomé, P.M.P.
- Retrofit measures evaluation considering thermal comfort using building energy simulation: two Lisbon householdsPublication . Gomes, Ricardo; Ferreira, Ana R.; Azevedo, Luís; Neto, Rui C.; Aelenei, Laura Elena; Silva, CarlosABSTRACT: Retrofit measures for buildings are in general evaluated considering the energy savings and life cycle cost. However, one of the main benefits, the increase of users comfort is very seldom analysed. In this work, two residential households representative of a large share of households in Portugal, were monitored and its thermal behavior was modeled using Energy Plus. The thermal evaluation of the pre-retrofit households shows that the winter season is problematic due to construction solutions and low availability for heating. The retrofit measures analysis was performed considering different retrofit solutions regarding envelope improvement and efficient systems implementation. In order to work around the question of comparing households that do not use energy for acclimatization and therefore have very low energy consumption, in the retrofit scenarios it was considered the thermal comfort evaluation value for the real case (pre-retrofit) and compared the energy consumption to achieve that same average comfort level (in this case avoiding high discomfort peaks). The measures that more rapidly pay the investment are those related with implementing active systems. The approach used in this paper, should be used in more calibrated models in order to have overall conclusions about the retrofit process at a larger scale.
- Aquaculture wastewater treatment through microalgal: biomass potential applications on animal feed, agriculture, and energyPublication . Viegas, Catarina; Gouveia, Luisa; Gonçalves, Maria MargaridaABSTRACT: The use of microalgae to remediate raw effluent from brown crab aquaculture was evaluated by performing batch mode growth tests using separately the microalgae Chlorella vulgaris (Cv), Scenedesmus obliquus (Sc), Isochrysis galbana (Ig), Nannocloropsis salina (Ns), and Spirulina major (Sp). Removal efficiencies in batch growth were 100% for total nitrogen and total phosphorus for all microalgae. Chemical oxygen demand (COD) remediations were all above 72%. Biomass productivity varied from 20.9 mg L-1 day- 1 (N. salina) to 146.4 mg L-1 day- 1 (C. vulgaris). The two best performing algae were C. vulgaris and S. obliquus and they were tested in semicontinuous growth, reaching productivities of 879.8 mg L-1 day- 1 and 811.7 mg L-1 day- 1, respectively. The bioremediation of the effluent was tested with a transfer system consisting of three independent containers and compared with the use of a single container. The single container had the same capacity and received weekly the same volume of effluent as the three containers together. The remediation capacity of the 3 containers was much higher than the single one. The supplementation with NaNO3 was tested to improve the nutrient removal microalgae? capacity, with positive results. The removal efficiencies were 100% for total nitrogen and total phosphorus and higher than 96% for COD. The obtained C. vulgaris and S. obliquus biomass were composed of 31 and 35% proteins, 6 and 8% lipids, 39 and 30% carbohydrates, respectively. The composition of these biomass suggest that it can be used as novel and sustainable ingredients in aquaculture feeds. The algal biomass of Cv and Sc were used as biostimulants in the germination of wheat and watercress, and very promising results were attained, with increases in the germination index for Cv and Sc of 175% and 48% in watercress and 84% and 98% in wheat, respectively. The biomasses of Cv and Sc were also subjected to a torrefaction process with 72.5 ? 1.7% char yields. The obtained biochars were tested as biostimulants for germination seeds (wheat and watercress) and as bio-adsorbent of dye solutions.
- Climate proofing the renewable electricity deployment in EuropePublication . Simões, Sofia; Amorim, Filipa; Siggini, Gildas; Saint-Drenan, Yves-Marie; Sessa, Valentina; Carvalho, S.C.P.; Mraihi, Hamza; Assoumou, EdiClimate and weather conditions influence energy demand. as well as electricity generation, especially due to the strong development of renewable energy. The changes of the European energy mix, together with ongoing climate change, raise a number of questions on impact on the electricity sector. In this paper we present results for the whole of the European power sector regarding on how considering current and future climate variability affects the results of a TIMES energy system model for the whole European power sector (eTIMES-EU) up to 2050. For each member-state we consider six climate projections to generate future capacity factors for wind, solar and hydro power generation. as well as temperature impact on electricity demand for heating and cooling. These are input into the eTIMES-EU model to assess how climate affects the optimal operation of the power system and if current EU-wide RES and emissions target deployment may be affected. Results show that although at EU-wide level there are no substantial changes, there are significant differences in countries RES deployment (especially wind and solar) and in electricity trade.
- 87Sr/86Sr dating of the Alcácer do Sal Formation (upper Miocene, mainland Portugal)Publication . Ressurreição, Ricardo; Legoinha, Paulo; Dias, Ruben Pereira; Santos, José Francisco; Ribeiro, Sara; Patinha, Carla; Miranda, RuiThe Lower Tagus Basin was subjected to several marine transgressions along the Neogene, related to positive eustatic oscillations and also controlled by the regional tectonic activity. In the Alcácer do SalSines region, previous studies identified an episode of marine sedimentation interpreted as having occurred during the late Serravalian to early Tortonian interval, based on biostratigraphic data. This episode is represented in the Alcácer do Sal Formation. The study of the SMS-12- 01B borehole, drilled for mineral prospection purposes, located about 10 km NNE of Melides, allowed the identification of a 3 m thick layer of sediments containing marine fossils. 87Sr/86Sr determinations of oyster shells point to deposition about 11.5 Ma ago, validating previous proposals for the age of the formation. These data correspond to the first numerical ages obtained for the Alcácer do Sal Formation, allowing a solid correlation with other known marine units in the Lower Tagus and Algarve basins related to the same transgression episode
- Thermal behavior of a BIPV combined with water storage: an experimental analysisPublication . Lourenço, José Marco; Aelenei, Laura Elena; Sousa, Miguel; Facão, Jorge; Goncalves, HelderABSTRACT: Buildings play an active role in the global energy consumption and are required to not only minimize their energy use, but also generate energy in a sustainable manner. The integration of renewable energies in building elements can improve their overall performance, as they are able to replace common construction materials, while offering both electrical and thermal energy. The scope of this paper is to present the first results of an experimental study of a Building-Integrated Photovoltaic system combined with a water storage tank (BIPV-WS), a combined integration not extensively studied yet. Both layers are separated by a ventilated air cavity, and the thermal behavior of the system was analyzed experimentally in real functioning conditions. The water tank performs as a thermal storage, maintaining a regular temperature of about 20-30 degrees C during a typical winter day of Lisbon for a period of 11 h. Moreover, through the ventilation of the air cavity, the heat provided by the solar panel was naturally recovered to the indoors of the building, while keeping the temperature high enough to heat up the water. During summer, the ventilated BIPV-WS enabled beneficial nocturnal heat loss while delaying diurnal space heating.