77 research outputs found
Integration of seismic, well, potential-field and geological data for ore prospecting in the Iberian Pyrite Belt
Ore prospecting using gravimetric and magnetic data has become one of the traditional approaches in
the last decades, often complemented with electric and electromagnetic methods. However, due to the
problem of non-uniqueness inherent to potential-filed modelling, constrains provided by structural
methods such as seismic reflection are often used. During the exploration of massive sulphide
polimetallic minerals in the Iberian Pyrite Belt Figueira de Cavaleiros sector, located in the Sado
Tertiary Basin, several gravimetric and magnetic anomalies were considered as interesting targets. In
order to reduce ambiguity of the gravimetric modelling and to confirm the geological model of the
area, two seismic reflection profiles were acquired. The interpretation of these profiles was assisted by
three mechanical boreholes, two of them located in the research area, in order to make a
seismostratigraphic interpretation. Unfortunately, the gravimetric modelling suggests that the anomaly
has a lithological and structural origin and is not related with massive sulphides. Nevertheless, a good
agreement between the seismic and potential-field data was achieved and new insights into the
geological model for the region were obtained form this work, with accurate data about the Tertiary
cover and Palaeozoic basement
Multispectral Indices for Wildfire Management
This paper highlights and summarizes the most important multispectral indices
and associated methodologies for fire management. Various fields of study are
examined where multispectral indices align with wildfire prevention and
management, including vegetation and soil attribute extraction, water feature
mapping, artificial structure identification, and post-fire burnt area
estimation. The versatility and effectiveness of multispectral indices in
addressing specific issues in wildfire management are emphasized. Fundamental
insights for optimizing data extraction are presented. Concrete indices for
each task, including the NDVI and the NDWI, are suggested. Moreover, to enhance
accuracy and address inherent limitations of individual index applications, the
integration of complementary processing solutions and additional data sources
like high-resolution imagery and ground-based measurements is recommended. This
paper aims to be an immediate and comprehensive reference for researchers and
stakeholders working on multispectral indices related to the prevention and
management of fires
Collision avoidance on unmanned aerial vehicles using neural network pipelines and flow clustering techniques
UIDB/04111/2020
PCIF/SSI/0102/2017
IF/00325/2015Unmanned Autonomous Vehicles (UAV), while not a recent invention, have recently acquired a prominent position in many industries, and they are increasingly used not only by avid customers, but also in high-demand technical use-cases, and will have a significant societal effect in the coming years. However, the use of UAVs is fraught with significant safety threats, such as collisions with dynamic obstacles (other UAVs, birds, or randomly thrown objects). This research focuses on a safety problem that is often overlooked due to a lack of technology and solutions to address it: collisions with non-stationary objects. A novel approach is described that employs deep learning techniques to solve the computationally intensive problem of real-time collision avoidance with dynamic objects using off-the-shelf commercial vision sensors. The suggested approach’s viability was corroborated by multiple experiments, firstly in simulation, and afterward in a concrete real-world case, that consists of dodging a thrown ball. A novel video dataset was created and made available for this purpose, and transfer learning was also tested, with positive results.publishersversionpublishe
Vineyard Gap Detection by Convolutional Neural Networks Fed by Multi-Spectral Images
Funding Information: This research was partially funded by Fundação para a Ciência e a Tecnologia under Projects UIDB/00066/2020, UIDB/04111/2020, foRESTER PCIF/SSI/0102/2017, and IF/00325/2015; Instituto Lusófono de Investigação e Desenvolvimento (ILIND) under Project COFAC/ILIND/COPELABS/1/2020; Project “(Link4S)ustainability—A new generation connectivity system for creation and integration of networks of objects for new sustainability paradigms [POCI-01-0247-FEDER-046122 | LISBOA-01-0247-FEDER-046122]” is financed by the Operational Competitiveness and Internationalization Programmes COMPETE 2020 and LISBOA 2020, under the PORTUGAL 2020 Partnership Agreement, and through the European Structural and Investment Funds in the FEDER component; and also IEoT: Intelligent Edge of Things under under Project LISBOA-01-0247-FEDER-069537. Publisher Copyright: © 2022 by the authors.This paper focuses on the gaps that occur inside plantations; these gaps, although not having anything growing in them, still happen to be watered. This action ends up wasting tons of liters of water every year, which translates into financial and environmental losses. To avoid these losses, we suggest early detection. To this end, we analyzed the different available neural networks available with multispectral images. This entailed training each regional and regression-based network five times with five different datasets. Networks based on two possible solutions were chosen: unmanned aerial vehicle (UAV) depletion or post-processing with external software. The results show that the best network for UAV depletion is the Tiny-YOLO (You Only Look Once) version 4-type network, and the best starting weights for Mask-RCNN were from the Tiny-YOLO network version. Although no mean average precision (mAP) of over 70% was achieved, the final trained networks managed to detect mostly gaps, including low-vegetation areas and very small gaps, which had a tendency to be overlooked during the labeling stage.publishersversionpublishe
Autonomous environment generator for uav-based simulation
Funding Information: Funding: This project has received funding from the ECSEL Joint Undertaking (JU) under grant agreement No 783119. The JU receives support from the European Union’s Horizon 2020 research and innovation programme and Austria, Belgium, Czech Republic, Finland, Germany, Greece, Italy, Latvia, Norway, Poland, Portugal, Spain, Sweden. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.The increased demand for Unmanned Aerial Vehicles (UAV) has also led to higher demand for realistic and efficient UAV testing environments. The current use of simulated environments has been shown to be a relatively inexpensive, safe, and repeatable way to evaluate UAVs before real-world use. However, the use of generic environments and manually-created custom scenarios leaves more to be desired. In this paper, we propose a new testbed that utilizes machine learning algorithms to procedurally generate, scale, and place 3D models to create a realistic environment. These environments are additionally based on satellite images, thus providing users with a more robust example of real-world UAV deployment. Although certain graphical improvements could be made, this paper serves as a proof of concept for an novel autonomous and relatively-large scale environment generator. Such a testbed could allow for preliminary operational planning and testing worldwide, without the need for on-site evaluation or data collection in the future.publishersversionpublishe
Orange pickeringite from the algares 30-level adit, aljustrel mine, iberian pyrite belt, portugal
Funding Information: Funding: Funding from FEDER (Fundo Europeu de Desenvolvimento Regional)/INTERREG POCTEP GEO-FPI - (Ref. 0052-GEO-FPI-5-E) and EXPLORA, Op ALT20-03-0145-FEDER-000025. Funding by Alentejo 2020, Portugal 2020 and the European Union (ERDF) is acknowledged. J.P. Veiga acknowledges FEDER funds through the COMPETE 2020 Programme and National Funds through the FCT-Portuguese Foundation for Science and Technology under the project UID/CTM/50025/2019, and SFRH/BD/145308/2019 (F.Carvalho) plus UIDP/50025/2020 (U.D. Menda), and funding from the European Institute of Innovation and Technology (EIT), a body of the European Union, under Horizon 2020, the EU Framework Programme for Research and Innovation, through the MineHeritage Project (PA 18111).The sheltered environment of the Algares +30 level adit (underground mine gallery) contributes to the preservation of secondary water-soluble minerals formed on the tunnel walls. The massive sulphide and related stockwork zone are hosted by the Mine Tuff volcanic unit and are exposed in the walls of the gallery, showing intense oxidation and hydrothermal alteration. Minerals from the halotrichite group were identified on the efflorescent salts, typically white fine-acicular crystals but also on aggregates with dark orange/brownish colour. Mineral characterization was performed using several methods and analytical techniques (XRD, XRF-WDS, SEM-EDS, DTA-TG), and the chemical formulas were calculated maintaining the ratio A:B∼= 1:2 in accordance with the general formula of the halotrichite group, AB2 (SO4 )4·22H2 O. This methodology allowed the assignment of the orange colour to the presence of trivalent iron on iron-rich pickeringite in partial substitution of aluminium.publishersversionpublishe
Levantamentos geofísicos no setor português da Faixa Piritosa Ibérica: perspetiva global da sua importância em prospeção de sulfuretos maciços e interpretação geológica
ABSTRACT: The application of geophysical techniques to massive
sulphide deposits exploration has proven to be a success in the Iberian
Pyrite Belt (IPB) metallogenetic province, both in Portugal and in Spain.
Several hidden deposits were discovered through the interpretation of
geological models, supported by geophysical data collected in land and
airborne surveys, as well as applied using down hole techniques in
selected drill holes. This paper presents an overview of the methodologies
applied in Portugal in the South Portuguese Zone (SPZ) geological
domain, where the IPB is included, mostly by the LNEG and mining
companies, with emphasis on the interpretation of the regional gravity,
magnetometry and radiometry surveys, published in 1/400 000 scale by
the EXPLORA/Alentejo2020 Project. In this regional mapping program,
the large volume of data collected by LNEG and mining companies since
the 1960’s was compiled and processed. The integrated interpretation and
correlation between these methods will enable a better planning of new
IPB exploration investments. IPB Volcano-Sedimentary Complex (VSC,
Famennian to Late Visean age) lineaments are well defined in the gravity
and magnetic fields along the IPB western region (e.g. Alcoutim/Neves Corvo/Montinho/Sesmarias/Lousal/Caveira). Aeromagnetic data also
reflect deep and large anomalies related with the SPZ basement. A rock
density database is presented and used to interpret the gravity data.
Radiometric map (Natural Radioactivity), based mostly in airborne
radiometric surveys, show contrasts between rocks in Paleozoic,
Mesozoic and Cenozoic formations and correlations with geological and
hydrothermal mapping are highlighted. The use of geophysical
techniques is particularly critical in areas where VSC is concealed by
younger sediments (e.g. Baixo Alentejo Flysch Group and/or Cenozoic
formations), allowing the selection of target areas. Case studies are
discussed based on electromagnetic, seismic and magnetotelluric methods
and on the high mineral potential of defined targets. Multilayered data
correlation (geophysics including petrophysical data, geochemistry and
stratigraphic high-resolution models) is a key prospecting methodology
and is essential for the accurate modelling of ore horizons and geological
structures. Considering the IPB potential for VMS deposits, including the
possible discovery of new giant (> 200 Mt) deposits, an increase of
investment in new geophysical methods can be predicted. LNEG
development of R&D projects such as EXPLORA/Alentejo2020 and
SmartExplorationTM/H2020 also contribute to a favourable setting in the
province, both in near mining and green fields scenarios. Thus, new
discoveries are expected, like others made in the recent times in the IPB
Portuguese sector, such as Lagoa Salgada (SFM, 1992, SFM;
Redcorp/EDM, 2011; Redcorp/Ascendant/EDM, 2017), Semblana
(Somincor-AGC-Lundin Mining, 2010), Monte Branco (Somincor Lundin Mining, 2012) and Sesmarias (Maepa/Avrupa, 2014). The
importance of these data goes beyond the mineral exploration purpose.
Since some of them use rock and mineral physical properties that can be
related with environmental contamination (e.g. radiometry and
magnetics) they can also be used in geochemical background studies, acid
mine drainage and metal dispersion. Therefore, they can also promote a
deeper knowledge in other areas of research related with environment
preservation.RESUMO: A aplicação de técnicas de prospeção geofísica na pesquisa de
jazigos de sulfuretos maciços na Faixa Piritosa Ibérica (FPI) tem-se
revelado um sucesso em Portugal e em Espanha. Vários jazigos ocultos
foram descobertos a partir da interpretação de modelos geológicos, com o
apoio de dados geofísicos recolhidos em levantamentos terrestres,
aerotransportados ou em profundidade, em sondagens (diagrafias). Neste
artigo, apresenta-se uma análise das metodologias aplicadas
principalmente pelo LNEG e empresas mineiras em Portugal, na Zona
Sul Portuguesa (ZSP), onde se insere a FPI. Destaca-se a interpretação
dos levantamentos regionais, esc. 1/400 000, de gravimetria,
magnetometria e radiometria (EXPLORA/Alentejo2020). Nestes
programas, foi feito o processamento de um volume de informação
significativo, a partir de dados obtidos desde a década de 1960. Neste
contexto indicam-se diversos alinhamentos de gravimetria e de
aeromagnetometria relativos a unidades geológicas com elevado
potencial mineiro, como o Complexo Vulcano-Sedimentar (CVS, idade
Famenniano a Viseano sup.), sobressaindo o eixo Alcoutim/Neves Corvo/Montinho/Sesmarias/Lousal/Caveira. Os dados de
aeromagnetismo refletem também anomalias com origens mais profundas
e relacionadas com a estrutura basal da ZSP. A base de dados de
densidades de rocha é utilizada na interpretação gravimétrica da FPI. O
mapa radiométrico (Radioatividade Natural), baseado fundamentalmente
em radiometria aeroportada (contagens totais) mostra o contraste à
superfície de litologias das formações paleozoicas, mesozoicas e
cenozoicas, sendo salientado, no primeiro caso, a sua correlação com a
cartografia de alterações hidrotermais. Em áreas onde o CVS se encontra
subjacente sob sedimentos mais recentes (ex. Grupo Flysch Baixo
Alentejo e formações cenozoicas), o uso de técnicas geofísicas é
fundamental para a seleção de alvos. São também descritos exemplos
sobre a aplicação de métodos eletromagnéticos, sísmicos e
magnetotelúricos na identificação e caracterização de estruturas
geológicas. A análise integrada de diferentes métodos geofísicos,
complementados com informação geológica e geoquímica, constitui a
melhor metodologia de prospeção, sendo essencial para a pesquisa de
horizontes de mineralização. Considerando a FPI como uma das principais províncias metalogenéticas do mundo, é expectável que
venham a ocorrer mais investimentos e assim serem identificados novos
jazigos, inclusive com dimensão superior a 200 Mt. Através de projetos
ID como o EXPLORA/Alentejo2020 e SmartExplorationTM/H2020 o
LNEG contribui para um melhor conhecimento na FPI em cenários de
prospeção near mining e green fields. Nesta perspetiva, são esperadas
novas descobertas de jazigos à semelhança do que tem acontecido em
Portugal, como por exemplo Lagoa Salgada (SFM-1992, Redcorp/EDM 2011, Redcorp/Ascendant/EDM-2017), Semblana (Somincor-AGC Lundin Mining, 2010), Monte Branco (Somincor-Lundin Mining, 2012) e
Sesmarias (Maepa/Avrupa, 2014). A importância destes dados vai muito
para além da prospeção mineira. Uma vez que alguns métodos utilizam
propriedades físicas que podem ser relacionadas com contaminações
ambientais. Certos métodos geofísicos como radiometria e
magnetometria, resistividade e métodos elétricos em geral, podem ser
utilizados também em trabalhos de investigação sobre background
geoquímico, drenagem ácida de mina e dispersão de metais. Desta forma,
a aplicação destes métodos promove também um conhecimento mais
aprofundado noutras áreas de investigação relacionadas com a
preservação do ambiente.info:eu-repo/semantics/publishedVersio
Structure, stratigraphy and hydrothermal alteration at the Gavião orebodies, Aljustrel : reconstruction of a dismembered ore-forming system at the Iberian Pyrite Belt and implications for exploration
Germanium-rich chalcopyrite from the Barrigão remobilised vein deposit, Iberian Pyrite Belt, Portugal
Anomalously high germanium contents have been detected by means of whole-rock trace element analysis in remobilised vein type copper ores from the abandoned Barrigão mine, located in the Iberian Pyrite Belt, southern Portugal. The late-Variscan brecciated copper ores consist manly of chalcopyrite, with minor tennantite, rare pyrite and arsenopyrite. The ores, investigated for elements increasingly used in several thin-film and other semiconductor high-technology applications (e.g. indium, selenium, tellurium and germanium), show germanium contents up to 280 ppm, with an average of 61 ppm from 10 samples. Electron Probe Microanalysis of Barrigão ore samples revealed that germanium is contained in chalcopyrite, with a range of 0.1 to 0.4 wt% (0.23 wt% average). High germanium contents seem to be linked to "dirty" chalcopyrite phases, showing irregular patchy zoning under the microscope and on back-scattered electron images
How to build a 2d and 3d aerial multispectral map?—all steps deeply explained
UIDB/04111/2020 PCIF/SSI/0102/2017 IF/00325/2015 UIDB/00066/2020The increased development of camera resolution, processing power, and aerial platforms helped to create more cost-efficient approaches to capture and generate point clouds to assist in scientific fields. The continuous development of methods to produce three-dimensional models based on two-dimensional images such as Structure from Motion (SfM) and Multi-View Stereopsis (MVS) allowed to improve the resolution of the produced models by a significant amount. By taking inspiration from the free and accessible workflow made available by OpenDroneMap, a detailed analysis of the processes is displayed in this paper. As of the writing of this paper, no literature was found that described in detail the necessary steps and processes that would allow the creation of digital models in two or three dimensions based on aerial images. With this, and based on the workflow of OpenDroneMap, a detailed study was performed. The digital model reconstruction process takes the initial aerial images obtained from the field survey and passes them through a series of stages. From each stage, a product is acquired and used for the following stage, for example, at the end of the initial stage a sparse reconstruction is produced, obtained by extracting features of the images and matching them, which is used in the following step, to increase its resolution. Additionally, from the analysis of the workflow, adaptations were made to the standard workflow in order to increase the compatibility of the developed system to different types of image sets. Particularly, adaptations focused on thermal imagery were made. Due to the low presence of strong features and therefore difficulty to match features across thermal images, a modification was implemented, so thermal models could be produced alongside the already implemented processes for multispectral and RGB image sets.publishersversionpublishe
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