Publications of Eric Pirard
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See detailPenser le cycle des métaux : clé de voûte pour une économie plus renouvelable
Pirard, Eric ULiege

Scientific conference (2021, March 27)

Nous qualifions de renouvelables les énergies du vent et du soleil, mais qu’en est-il des métaux qui sont les indispensables vecteurs de la conversion vers une énergie électrique ? La croissance ... [more ▼]

Nous qualifions de renouvelables les énergies du vent et du soleil, mais qu’en est-il des métaux qui sont les indispensables vecteurs de la conversion vers une énergie électrique ? La croissance exponentielle de la production des métaux, amorcée depuis plus d’un siècle, ne va certainement pas fléchir dans les prochaines décennies. L’extraction des ressources va se poursuivre à un rythme effréné pour satisfaire les besoins de la transition écologique, que ce soit pour la production et le stockage d’énergie, pour nos envies de mobilité, ou encore pour nos besoins de communication numérique. N’est-il pas urgent, par géomimétisme, d’apprendre à penser le cycle des métaux et à jeter les bases d’une économie plus circulaire ? Les défis qui attendent nos sociétés sont de mettre en place les règles favorisant un cycle de vie plus durable, d’adapter le comportement des consommateurs, mais aussi de repenser nos produits car ils seront la mine urbaine des générations futures. [less ▲]

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See detailRessources Métalliques et Environnement
Pirard, Eric ULiege

Scientific conference (2021, February 12)

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See detailCloud and Cloud-Shadow Detection for Applications in Mapping Small-Scale Mining in Colombia Using Sentinel-2 Imagery
Ibrahim, Elsy ULiege; Jiang, Jingyi; Lema, Luisa et al

in Remote Sensing (2021), 13(4 736),

Small-scale placer mining in Colombia takes place in rural areas and involves excavations resulting in large footprints of bare soil and water ponds. Such excavated areas comprise a mosaic of challenging ... [more ▼]

Small-scale placer mining in Colombia takes place in rural areas and involves excavations resulting in large footprints of bare soil and water ponds. Such excavated areas comprise a mosaic of challenging terrains for cloud and cloud-shadow detection of Sentinel-2 (S2A and S2B) data used to identify, map, and monitor these highly dynamic activities. This paper uses an efficient two-step machine-learning approach using freely available tools to detect clouds and shadows in the context of mapping small-scale mining areas, one which places an emphasis on the reduction of misclassification of mining sites as clouds or shadows. The first step is comprised of a supervised support-vector-machine classification identifying clouds, cloud shadows, and clear pixels. The second step is a geometry-based improvement of cloud-shadow detection where solar-cloud-shadow-sensor geometry is used to exclude commission errors in cloud shadows. The geometry-based approach makes use of sun angles and sensor view angles available in Sentinel-2 metadata to identify potential directions of cloud shadow for each cloud projection. The approach does not require supplementary data on cloud-top or bottom heights nor cloud-top ruggedness. It assumes that the location of dense clouds is mainly impacted by meteorological conditions and that cloud-top and cloud-base heights vary in a predefined manner. The methodology has been tested over an intensively excavated and well-studied pilot site and shows 50% more detection of clouds and shadows than Sen2Cor. Furthermore, it has reached a Specificity of 1 in the correct detection of mining sites and water ponds, proving itself to be a reliable approach for further related studies on the mapping of small-scale mining in the area. Although the methodology was tailored to the context of small-scale mining in the region of Antioquia, it is a scalable approach and can be adapted to other areas and conditions. [less ▲]

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See detailSmall-scale surface mining of gold placers: Detection, mapping, and temporal analysis through the use of free satellite imagery
Ibrahim, Elsy ULiege; Lema, Luisa; Barnabé, Pierre ULiege et al

in International Journal of Applied Earth Observation and Geoinformation (2020), 93

Informal small-scale mining is spread in many countries and provides livelihood to numerous families in rural areas yet often with devastating social and environmental impacts. The alluvial gold mining ... [more ▼]

Informal small-scale mining is spread in many countries and provides livelihood to numerous families in rural areas yet often with devastating social and environmental impacts. The alluvial gold mining process in Colombia, also known as placer mining, involves excavations using heavy machinery and creates large footprints of bare soil and mining ponds. The very dynamic nature of this extractive activity and its spread in rural and remote areas make its mapping and monitoring very challenging. The use of freely available satellite data of the Copernicus programme provides great new possibilities to study these activities and provides stakeholders integrated data to better understand the spatial and temporal extent of the activities and mitigate affected areas. The objective of this work is to assess the potential of Sentinel-2 data to identify mining areas and to understand the dynamics in landcover change over a study area located at the border of the municipalities of El Bagre and Zaragoza in Bajo Cauca, Colombia. The study utilizes a classification approach followed by post-processing using field knowledge on a set of images from 2016 to 2019. Sequential pattern mining of classified images shows the likelihood of certain annual and seasonal changes in mining-impacted landcover and in the natural vegetation. The results show a slight reduction in the detected mining areas from 2016 to 2019. On the other hand, there are more mining activities in the dry season than in the wet season. Excavated areas of bare soil have a 50% chance to remain in excavation over the considered period or they transition to non-vegetated areas or mining ponds. Vegetation loss due to the extractive activities corresponds to about 35% while recovered vegetated areas are 7% of the total excavated areas in June 2019. An analysis of abandoned sites using NDVI shows that it takes a much longer period than the one considered in this paper for potential natural recovery of vegetation. Finally, the work was disseminated among stakeholders and the public on MapX (https://mapx.org), an online open platform for mapping and visualizing geospatial data on natural resources. It is a pilot study the will be the basis of the analysis of more regions in the department of Antioquia. [less ▲]

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See detailLe laminoir à zinc de Tilff au XIXème siècle
Pirard, Eric ULiege

in Archéo-contact Vieil Esneux (2020), 56

Le laminoir du nouveau moulin de Tilff acquis par la société de la Vieille-Montagne en 1837 et transformé en laminoir à feuilles de zinc a été en activité jusqu'en 1953. Son histoire, étroitement associée ... [more ▼]

Le laminoir du nouveau moulin de Tilff acquis par la société de la Vieille-Montagne en 1837 et transformé en laminoir à feuilles de zinc a été en activité jusqu'en 1953. Son histoire, étroitement associée à celle du village, est bien documentée au travers des rapports d'ingénieurs consignés dans les archives de la société et est bien illustrée grâce aux remarquables aquarelles de A. Maugendre. [less ▲]

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See detailLa quadrature de l'économie circulaire
Pirard, Eric ULiege

Conference given outside the academic context (2020)

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See detailOù sont les métaux pour les technologies du futur?
Pirard, Eric ULiege

Conference given outside the academic context (2020)

Pendant des siècles l'homme s'est contenté d'exploiter les énergies renouvelables. Il se contentait également d'élaborer des objets simples au départ de sept métaux abondants et faciles à travailler. La ... [more ▼]

Pendant des siècles l'homme s'est contenté d'exploiter les énergies renouvelables. Il se contentait également d'élaborer des objets simples au départ de sept métaux abondants et faciles à travailler. La mécanisation et la maîtrise des énergies fossiles a engendré un cortège d'innovations technologiques sans précédent. Il est désormais impensable de se passer des équipements mobiles et de renoncer à se déplacer au quotidien. Mais, la transition écologique tant vantée a un coût. Elle mobilise de très nombreuses ressources métalliques et induit une activité minière comme jamais auparavant dans l'histoire de l'humanité. A travers cet exposé, nous verrons comment la mise en place d'une véritable économie circulaire des métaux est la seule voie possible vers un développement raisonné. [less ▲]

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See detailMicroscopie corrélative et traitement d'images pour la réalisation de cartographies minéralogiques automatisées
Pirard, Eric ULiege; Bouzahzah, Hassan ULiege

Scientific conference (2019, June 04)

La réalisation de cartographies minéralogiques de sections de roches par le biais de microscopes électroniques à balayage (MEB) équipés d’analyseurs EDX s’est largement répandue au cours des dernières ... [more ▼]

La réalisation de cartographies minéralogiques de sections de roches par le biais de microscopes électroniques à balayage (MEB) équipés d’analyseurs EDX s’est largement répandue au cours des dernières années (QEM-SCAN ; MLA ; TIMA ; INCA-MINERAL ; MINERALOGIC ;…). Toutefois, cette technique reste très largement tributaire de l’expertise de l’opérateur et de sa connaissance préalable du contexte minéralogique. L’utilisation de la microscopie corrélative (optique + BSE + EDX) permet d’envisager le développement de stratégies d’analyse plus rapides et plus précises. Les développements les plus récents en classification et en intelligence artificielle devraient également permettre d’obtenir des cartographies plus exactes tout en minimisant l’intervention humaine. [less ▲]

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See detailDisponibilité durable des matières premières pour la transition énergétique
Pirard, Eric ULiege

Conference given outside the academic context (2019)

Detailed reference viewed: 367 (18 ULiège)
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See detailDEVELOPMENT OF ADVANCED IMAGING TECHNIQUES FOR REAL TIME PARTICLE SENSING IN MINERAL PROCESSING AND RECYCLING
Leroy, Sophie ULiege; Barnabé, Pierre ULiege; Dislaire, Godefroid ULiege et al

in Rosenkranz, Jan (Ed.) Konferens i Mineralteknik (2019, February 06)

With the ever increasing pressure for digitization and optimization of mineral processing operations, there is a growing need for real-time monitoring solutions providing informations about individual ... [more ▼]

With the ever increasing pressure for digitization and optimization of mineral processing operations, there is a growing need for real-time monitoring solutions providing informations about individual particles and their nature. This paper briefly reviews existing on-stream analytical techniques and stresses the need for “single particle sensing systems”. A series of technologies developed at ULiège, GeMMe, are presented together with a small case study. [less ▲]

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See detailRemote Sensing and Mineral Resources
Pirard, Eric ULiege

Conference (2018, June 11)

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See detailThe role of microscopy in the Circular Economy
Pirard, Eric ULiege; Bouzahzah, Hassan ULiege; Castroviejo, Ricardo et al

Scientific conference (2018, May 16)

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See detailL’approvisionnement en métaux critiques: Importance, stratégies et impact
Pirard, Eric ULiege

Conference given outside the academic context (2018)

De l’Âge de la Pierre à l’Âge du Lithium, nous n’avons eu de cesse d’exploiter les ressources naturelles et de perfectionner nos outils. Baignant dans une abondance de technologies, nous ne nous soucions ... [more ▼]

De l’Âge de la Pierre à l’Âge du Lithium, nous n’avons eu de cesse d’exploiter les ressources naturelles et de perfectionner nos outils. Baignant dans une abondance de technologies, nous ne nous soucions plus guère des matières premières qui les rendent possibles et ignorons souvent que leur production est aux mains d’économies émergentes. Depuis 2010, avec son « Initiative Matières Premières », l’Europe se préoccupe de sa situation de forte dépendance vis-à-vis de l’approvisionnement en métaux. Entre les métaux de base et les métaux précieux sont tout d’un coup apparus des métaux qualifiés de « critiques » ( à ne pas confondre avec les Terres Rares ). La criticité est une notion multiple qui possède au moins trois dimensions : géologique, technologique et géopolitique. En prenant l’exemple de quelques métaux emblématiques, l’orateur mettra en évidence les causes d’une possible criticité. Puis, il s’interrogera sur les stratégies possibles pour mitiger notre dépendance et montrera que, tout compte fait, la criticité n’est sans doute pas là où l’on s’y attend le plus ! Enfin, il décrira de qui est fait à ce sujet en Région Wallonne, avec d’importants programmes d’innovation technologique qui associent universités, centres de recherche et entreprises, et permettent à ces acteurs de se positionner au cœur des réseaux européens sur l’économie circulaire des métaux. [less ▲]

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See detailRawMatCop: Developing Skills at the intersection between Earth observation and the raw materials community
Louis, Andreani; Ibrahim, Elsy ULiege; Marzan, Ignacio et al

Poster (2018, April 19)

The RawMatCop programme was launched in 2017 and aims to develop skills, expertise, demonstrations, and applications of Copernicus data to the raw materials sector. It is co-funded by the European ... [more ▼]

The RawMatCop programme was launched in 2017 and aims to develop skills, expertise, demonstrations, and applications of Copernicus data to the raw materials sector. It is co-funded by the European Commission (DG for Internal Market, Industry, Entrepreneurship and SMEs) and the EIT RawMaterials (RawMaterials Academy). Raw materials have become increasingly important to the European Union's economy, growth, and competitiveness. In this context, the EU aims to facilitate the exchange of best practices among its member states to improve the sustainable and safe supply of raw materials to the EU economy and society. Thus, monitoring of mining activities and environmental impact of waste and residue management are key issues of that strategy. With state-of-the-art spaceborne imagery, Copernicus has a strong potential in contributing to EU’s requirements and expectations. The aim of RawMatCop is to illustrate the usefulness of Copernicus data through three 'Research & Application Areas’ relevant for the raw materials sector: (1) multi-scale and multi-source exploration, (2) spatiotemporal mapping of dust dispersion around mining sites, (3) monitoring of surface/subsurface deformation. Multispectral data proves to be an incredible tool for regional scale mapping of surface alterations associated to mineralization or mining activities. One clear advantage of Sentinel-2 data over other sensors is that it has a good coverage of the visible and near infrared portion of the electromagnetic spectrum, which makes it an ideal tool for mapping iron-oxides. The current activities of RawMatCop include mapping alterations and iron features associated to Volcanic Hosted Massive Sulfides (Iberian Pyrite Belt, Spain) as well as mapping the weathering of lateritic profiles and iron-oxide associated to active mining in New Caledonia. For this purpose, several workflows based on downscaling from satellite-based to in-situ observations are being tested. Furthermore, RawMatCorp is also contributing to the consistency assessment of popular atmospheric correction approaches used for Sentinel-2 processing (iCOR, Sen2Cor, MAJA) and the influence of the mining setting on their performance. Moreover, ground deformation is one of the most important hazards related to mining activities, and RawMatCorp is also addressing this topic through monitoring the Riotinto mine (SW Spain). This monitoring utilizes SAR and passive seismic techniques to develop a joint Early Warning System aiming to reduce risks on ground mechanical integrity. [less ▲]

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See detailGeophysical Investigation of the Pb–Zn Deposit of Lontzen–Poppelsberg, Belgium
Evrard, Maxime ULiege; Dumont, Gael ULiege; Hermans, Thomas et al

in Minerals (2018), 8(6 233),

The drillhole information from the Lontzen–Poppelsberg site has demonstrated three orebodies and has allowed the estimation of the extension of the lodes, their dip, and the location at the ground surface ... [more ▼]

The drillhole information from the Lontzen–Poppelsberg site has demonstrated three orebodies and has allowed the estimation of the extension of the lodes, their dip, and the location at the ground surface. The localisation of the lodes makes them excellent targets for further exploration with geophysics. This deposit is classified as a Mississippi Valley Type (MVT) deposit. It consists mainly of Pb–Zn–Fe sulphides that display contrasting values in resistivity, chargeability, density, and magnetic susceptibility, with regards to the sedimentary host rocks. The dipole–dipole direct current (DC) resistivity and induce polarization (IP) profiles have been collected and inverted to successfully delineate the Pb–Zn mineralization and the geological structures. Short-spacing EM34 electromagnetic conductivity data were collected mainly on the top of Poppelsberg East lode and have revealed a conductive body matching with the geologically modelled mineralization. Gravity profiles have been carried out perpendicularly to the lode orientation; they show a strong structural anomaly. High resolution ground magnetic data were collected over the study area, but they showed no anomaly over the ore deposits. The geophysical inversion results are complementary to the model based on drill information, and allow us to refine the delineation of the mineralization. The identification of the geophysical signatures of this deposit permits targeting new possible mineralization in the area. [less ▲]

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See detailA Study of Ground Movements in Brussels (Belgium) Monitored by Persistent Scatterer Interferometry over a 25-Year Period
Declercq, Pierre-Yves; Walstra, Jan; Gérard, Pierre et al

in Geosciences (2017), 7(115), 1-17

The time series of Synthetic Aperture Radar data acquired by four satellite missions (including ERS, Envisat, TerraSAR-X and Sentinel 1) were processed using Persistent Scatterer interferometric synthetic ... [more ▼]

The time series of Synthetic Aperture Radar data acquired by four satellite missions (including ERS, Envisat, TerraSAR-X and Sentinel 1) were processed using Persistent Scatterer interferometric synthetic aperture radar (InSAR) techniques. The processed datasets provide a nearly continuous coverage from 1992 to 2017 over the Brussels Region (Belgium) and give evidence of ongoing, slow ground deformations. The results highlight an area of uplift located in the heart of the city, with a cumulative ground displacement of ±4 cm over a 25-year period. The rates of uplift appear to have decreased from 2 to 4 mm/year during the ERS acquisition period (1992–2006) down to 0.5–1 mm/year for the Sentinel 1 data (2014–2017). Uplift of the city centre is attributed to a reduction of groundwater extraction from the deeper (Cenozoic-Paleozoic) aquifers, related to the deindustrialization of the city centre since the 1970s. The groundwater levels attested by piezometers in these aquifers show a clear recharge trend which induced the uplift. Some areas of subsidence in the river valleys such as the Maelbeek can be related to the natural settlement of soft, young alluvial deposits, possibly increased by the load of buildings. [less ▲]

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See detailTowards a more automated mineralogy
Pirard, Eric ULiege

in Proceedings SGA2017 (2017, August)

Automated mineralogy has been around for more than thirty years as the reference technique to support process mineralogy and geometallurgical studies. Pioneering techniques such as the QEM-SEM have been ... [more ▼]

Automated mineralogy has been around for more than thirty years as the reference technique to support process mineralogy and geometallurgical studies. Pioneering techniques such as the QEM-SEM have been further improved to benefit from the latest hardware developments in terms of stable, sensitive and efficient imaging. FEG sources, solid state x-ray detectors and almost real-time signal processing have made the most significant contributions in the last decade. A quick overview of existing technologies reveals that further improvement could be gained by merging different imaging modes and using more advanced classification algorithms such as those well known in machine learning and remote sensing. If such algorithms were complemented with hierarchical databases wherein only important economic minerals are listed with their associated probabilities of occurrences, significant improvements could be gained in automated mineral identification. This paper contributes to demonstrate that a real “mineral intelligence” of ores and materials is now within reach [less ▲]

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See detailApplication of Mid-infrared Reflectance Spectroscopy for the Identification of Minerals Present in Oil & Gas/Mining Exploration
Joassin, Marjorie; Pirard, Eric ULiege; Germay, Christophe

in Proceedings SGA2017 (2017, August)

This work aims to develop a new core logging technique based on reflectance spectroscopy in the mid-infrared domain (2.08 to 25 μm). This technique is suitable to analyse the mineralogy of rough surfaces ... [more ▼]

This work aims to develop a new core logging technique based on reflectance spectroscopy in the mid-infrared domain (2.08 to 25 μm). This technique is suitable to analyse the mineralogy of rough surfaces and will be adapted on a rock strength testing machine that scratches the core surface. The FT-IR spectrometer used in this work was tested on a list of minerals which are important in oil & gas and mining exploration. The list contains species of carbonates, halides, phosphates, sulphates, sulphides, tectosilicates and phyllosilicates. Then, a semi-automatic method was developed for mineral identification, mapping and quantification on the rough surfaces. It will be demonstrated that this process is powerful for the estimation of the mineral distribution at the exploration stage. Moreover, as it is non-destructive, low cost and quite fast, it will thus be helpful to extract additional data from the cores in a profitable way. This is critical to improve the resource efficiency, to reduce operational risks and to optimise the production in a sustainable way. These knowledges are the basis of the geometallurgical concept [less ▲]

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See detailBGDb.be: a map based search tool for geological publications
Stévens, Pierre; Pirard, Eric ULiege; Anceau, Annick ULiege

Conference (2017, July 01)

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See detailDe la Wallonie à l'Europe, les communautés de l'innovation (KIC) se mettent au service de la valorisation des déchets métalliques.
Pirard, Eric ULiege

in Pin, Dominique; Thibault, Olivier (Eds.) DES TERRITOIRES À L’EUROPE : Construire ensemble les transitions environnementales (2017, June)

La vallée de la Meuse, un des creusets historiques de la métallurgie européenne, accueille plusieurs projets d’innovation technologique dédiés au recyclage des métaux. Basés sur un partenariat public ... [more ▼]

La vallée de la Meuse, un des creusets historiques de la métallurgie européenne, accueille plusieurs projets d’innovation technologique dédiés au recyclage des métaux. Basés sur un partenariat public-privé au sein du pôle wallon Mecatech, ces projets visent à positionner la Wallonie comme une communauté de l’innovation au cœur du nouveau consortium européen EITRawMaterials. [less ▲]

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