The nickel laterite mining industry faces lower recovery rates related to low ore grades, multiple nickel carrying minerals, as well as lateral and vertical heterogeneities at ore deposit scale. Garnierite, a complex mixture of nickel-bearing phyllosilicates, occurs at the base of nickel laterite profiles. Samples of Ni-rich and Ni-poor phyllosilicates from garnierite and host saprolite, from New Caledonia and the Dominican Republic, were analyzed by laboratory X-ray diffractometry (XRD), Fourier Transform Infrared (FTIR) and Raman spectroscopies. These phyllosilicates are mainly composed of serpentine-, talc-and/or sepiolite-like phases. XRD allows clearly distinguishing the different phyllosilicate phases. Moreover, it shows a difference between Ni-rich and Nipoor phases after refinement of the diffractograms, in particular the (060) reflection, little exploited at present. When Ni is present, the peaks are broader and the spacing corresponding to the (060) reflection tends to be less than 1.534 A. Mg substitution by Ni also cause shifts of hydroxyl bands in FTIR (3500-3800 cm-1 and 500-800 cm-1 spectral range), and Raman spectra (3500-3700 cm-1 spectral range). Moreover, the intensities of the bands can be correlated with the Ni content. Both are reliable indicators to define the nature of garnierite. In Raman spectroscopy, the substitution of Mg by Ni generates shifts on most bands, and there is a variation in intensity ratios between several bands which are correlated with Ni content. Our results can be applied to spectra obtained by online and handheld analytical devices, in-field core scanners or XRD/X-Ray fluorescence (XRF) combined expert systems.

Asbestos refers to silicate minerals belonging to the serpentine group (chrysotile) and the amphibole group (crocidolite, amosite, tremolite-asbestos, anthophyllite-asbestos and actinolite-asbestos). Such materials have strong effect on health, and real-time instrumentation is on demand to detect asbestos. The current real-time techniques use only some aspects of the optical properties of asbestos, since the scattering properties (brightness and linear polarization scattering functions) of the various natures of asbestos has not been yet fully determined. We present here the brightness and linear polarization scattering functions for 6 natures of asbestos in the 425-1650 nm spectral domain obtained with the PROGRA2 instrument. Although the samples exhibit different shapes, the linear polarization values remain low, bell-shaped as usual for irregular particles, and close to those of mineral particles previously studied with PROGRA2. On the opposite, asbestos brightness curves present strong differences for the different samples. The chrysotile is darker than the other samples in the 80 degrees-150 degrees angle range, probably due to its tubular shape that can act as a light trap for scattering angles greater than a few tens of degrees. Other asbestos particles can be distinguished from building materials such as glass wool or plaster through their brightness curves in some scattering angle ranges. These new laboratory measurements indicate that the optical scattered properties could be used in the future to tentatively detect asbestos particles in a medium generated from building materials. (C) 2020 Elsevier Ltd. All rights reserved.

Summary SOLSA is the first automated expert system for on-site cores analysis. The scope is to provide a prototype to be an innovative and necessary tool for geo-metallurgy, in order to optimize the valorization of the ore. The Expert System consists in the combination of an integrated drilling rig providing cores of high quality, an automated scanner and phase identification software, developed for nickel laterites and bauxites but usable as well in other sectors. SOLSA combines non-destructive sensors and the whole system is driven by an innovative, user-friendly and intelligent software. SOLSA provides more complete information while optimizing the exploration stage, with a significant reduction of costs and return time. Such objective involves, in the first place, to fast, cheaper and systematic acquisition of the data needed for optimizing the process. The adding value takes place first at the exploration or grade control stage, furnishing systematic characterization and regionalization of the different types of ore. Then such information can be used for improving the ore scheduling at the mining and processing stages, toward improving the recovery and efficiency of the processing.

Asbestos is a commercial term which refers to six minerals that crystallize as fibrous bundles made of very thin and easily separable fibrils. Asbestos fibers have been exploited for a long time and voluntary added in a very large set of manufactured products. In France, asbestos is prohibited since an official decree published in 1997 that prohibits the manufacture, processing, sale and import of asbestos. The asbestos ban has been the subject of an European directive published in 1999. Following this ban, a standard was defined in order to specify the sampling, preparation and identification methods for asbestos fibers in samples of commercial origin (ISO 22262-1). For natural materials, no specific analytical protocol is currently defined in France. Searching for asbestos in a rock sample, the commonly used protocols require the reduction of the sample, the grinding of a sub-sample (1 to 2 g) and its calcination in order to eliminate organic matter, then an acid attack to dissolve some constituents (calcite, gypsum). The final test portion (~ 20 mg) is mixed in water, stirred using ultrasound, filtered through a metallized membrane and covered with a new layer of carbon before it can be examined using a transmission electron microscope. The protocols currently used are long and complex and require the grinding of the sub-sample. This grinding operation is a critical step because it can lead, starting from non-asbestiform minerals, to the artificial formation of more or less fine and elongated fibriform particles (cleavage fragments), quite similar in some cases to asbestos fibers. Grinding is therefore an operation liable to affect the quality of the final diagnosis. The new protocol presented here was built with the aim of developing an analytical approach specific to coherent rock samples. This protocol does not involve the grinding of the sample and allows the in-situ morphological and chemical characterization of fibrous minerals. It is based on the use of combined analytical techniques (MOLP, EPMA, FESEM-EDS, FIB-SEM, and confocal RAMAN in SEM) from a single support corresponding to a polished thin section. This protocol allows to observe the natural morphologies of the fibers, to measure their dimensions, to characterize the relationships between fibers and the other mineralogical constituents while preserving the texture of the rock and to acquire precise chemical analyzes of the fibers. It also overcomes problems related to the grinding of the sample and the formation of cleavage fragments. This protocol has been tested through the study of several types of massive rock samples. It provides a representative and reliable in-situ diagnosis of the initial state of the fibers in solid rocks.

In order to develop a mineralogical and chemical database, which will be associated with an on-line-on mine instrument, for nickel mining exploration, several garnierite samples were studied in laboratory. The collected samples are Ni-bearing laterites from New Caledonia and Dominican Republic and are mainly composed of serpentine-like and/or talc-like and/or sepiolite-like phase. These three types of phases are clearly differentiated by X-ray diffractometry (XRD). The presence of Ni within the crystallographic structure of these phases can be observed from the infrared or Raman spectra, where the effect of Mg/Ni substitutions causes shifts in some bands. The relative intensity of these bands can be correlated with the Ni content. These different parameters are a reliable indicator to define the nature of garnierite and to have an indication on the Ni content.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Detection and Identification of Asbestos in Aerosols by LIBS in a Low Temperature Plasma Cédric Duée, Marie Hénault, Thomas Lecas, Laifa Boufendi, Henry Pillière, Xavier Bourrat

Different techniques have been combined to determine the crystallography and the chemical composition of serpentinized harzburgite sampled in a drill core coming from the lower part of the New Caledonia ophiolite. Specifically, this serpentinized harzburgite is the common bedrock of most of the nickel laterite mines in New Caledonia. Most of the minerals present in serpentinized harzburgite were analyzed by Raman spectroscopy and XRD. In this study, Raman spectroscopy has been applied for the first time to estimate the nickel content in lizardite, forsterite, talc, and goethite. The analyses confirm that the major serpentine minerals show two varieties: (1) Ni-bearing lizardite and (2) Ni-free lizardite. Furthermore, Ni-rich forsterite, enstatite, Ni-rich talc, sepiolite, periclase (MgO), and quartz were detected. Additionally, Raman spectroscopy evidence minor phases not detected by XRD: anatase, rutile, pyrite, hematite, chromite, magnesiochromite, and Ni-rich goethite. Our results show that the Ni substitution is only present in lizardite exhibiting turbostratic-stacking disorder. This finding has potential for being used as an exploration tool using short-wave-infrared spectroscopy online or as a portable instrument, and for defining geometallurgical parameters for processing these complex ores.

The objective of the SOLSA project (EU-H2020) is to develop an analytical expert system for on-line-on-mine-real-time mineralogical and geochemical analyses on sonic drill cores. As one aspect of the system, this paper presents the building of the hyperspectral library and its incorporation into sparse unmixing techniques for mineral identification. Twenty seven spectra representing 14 minerals have been collected for the library. Three sparse unmixing techniques have been investigated and evaluated using simulated data generated from our hyperspectral library, and real hyperspectral data acquired from a serpentinized harzburgite sample. Among the three techniques, the collaborative sparse unmixing by variable splitting and augmented Lagrangian (CLSUnSAL) method provided the best accurate results on the simulated data. In addition, the results of the CLSUnSAL method show high correlation with that of the QEMSCAN® analysis on the harzburgite hyperspectral data.

On-line-real-time combined mineralogical and chemical analyses on drill cores are highly demanded by mining and metallurgical companies to speed up exploration and mining, as they provide more precise geomodels, and optimal definition of metallurgical parameters. The EU-H2020 SOLSA project (www.solsa-mining.eu), targets to construct an expert system coupling sonic drilling with an on-linereal-time analytical system combining systematic mineralogical and chemical analyses on drill cores. The analytical system comprises a profilometer, a high resolution RGB camera, VNIR (Visible Near Infrared)/SWIR (Shortwave Infrared) (Specim Ltd., Finland) hyperspectral cameras, and a XRF spectrometer. The objective is to reach real-time decision making through scanning of about 60 m drill cores per day. The system will be validated for nickel laterites, which represent 70 % of the Ni resources worldwide. SOLSA will provide open databases for combined analyses. Therefore, a hyperspectral open data base is built for nickel-laterite specific rocks and pure mineral samples. All these samples are also analyzed by conventional laboratory methods (XRD, Raman spectroscopy, SEM, EPMA and QEMSCAN ® ). Currently, 27 spectra representing 14 minerals (i.e., asbolane, chromite, diaspore, olivine (forsterite), clay minerals (kaolinite, saponite, pimelite), magnesite, pyroxene (enstatite), serpentine (lizardite, nepouite, antigorite), talc, calcite) have been collected for our hyperspectral library. We plan to open it to public at https://solsa.crystallography.net/sod/. As the spectra of drill cores often contain a mixture of minerals, spectral unmixing techniques have been investigated and implemented. We employed sparse unmixing techniques, which have connections with the statistical and geometrical frameworks and have recently been demonstrated a great success in unmixing hyperspectral data for remote sensing applications. Sparse unmixing techniques aim at finding the optimal subset of signatures in a spectral library that can best model each mixed pixel. The methods exploit the fact that a spectrum always contains a mixture of a small numbers of endmembers, which is the case in our data acquired from the nickel-laterite samples. Among investigated unmixing methods, the collaborative sparse unmixing by variable splitting and augmented Lagrangian (CLSUnSAL) method provided the most accurate unmixing results on simulated data that were generated from our hyperspectral library. Hyperspectral data acquired from a serpentinized harzburgite sample (SOLSA label of ER-MB00-0012) on a polished surface, were processed by the CLSUnSAL method using our hyperspectral library. The same sample was analyzed by QEMSCAN ® . A good correlation was found for the mineralogy and mineral distribution (olivine, pyroxene, serpentine, chromite) between the results of the CLSUnSAL and QEMSCAN ® methods. These analyses will be cross-evaluated by the Raman spectroscopy mapping.

On-line, real-time chemical and mineralogical analyses on drill cores are highly demanded by mining companies. However, they are a challenge because of drill core surface state and sample heterogeneities. We selected four rock samples: highly porous, siliceous breccia and serpentinized harzburgite coming from the base of a nickel laterite profile in New Caledonia which were sonic drilled, and fine grained, homogeneous sandstone and coarse grained granite which were diamond drilled and provided by Eijkelkamp Sonic Drill with unknown origin. The samples were analysed at five surface states (diamond or sonic drilled, cut as squares, polished at 6 and 0.25 mu m, powdered < 80 mu m) by portable XRF spectroscopy (pXRF) in mining and soil modes and portable infrared spectroscopy (pIR, Visible and Near Infrared-Short Wave Infrared range (VNIR-SWIR)). A total of 52 pXRF and 200 pIR analyses were performed per sample at each surface state. This study shows that the surface state has minor influence on the results of the portable instruments. By comparing pIR and pXRF results with laboratory devices (Raman spectroscopy, XRD with Rietveld refinement, XRF spectroscopy and ICP-AES), we evidence the lower and less accurate information obtained from handheld instruments in terms of chemistry and mineralogy. The porosity and grain size effect on the measurement need to be taken into consideration for on-line drill core analyses. We show that the combination of complementary analytical techniques helps to overcome the drawbacks of the core texture and of the precision of portable instruments in order to define the regions of interest (ROI) for mining companies. We also demonstrate that a precise pXRF calibration is mandatory and that the concentration of light elements (Si, Mg), even if not accurate, shows sufficient contrast along the lateritic profile for ROI definition.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. PLASMIANTE: A plasma filter for the detection of airborne asbestos. Cédric Duée, Marie Hénault, Thomas Lecas, Laifa Boufendi, Xavier Bourrat, Hubert Haas, Henry Pillière

Within the framework of responsible mining, a SOLSA project (www.solsa-mining.eu) to develop an in-situ tool allowing a quick mineralogical identification of site drill cores has been recently launched. Its objective is to develop new or improved highly-efficient and cost-effective, sustainable exploration technologies. It combines and integrates non-destructive sensors: X-ray fluorescence, X-ray diffraction, infra-red and Raman spectroscopy and 3D imaging. The challenge is to address mixtures of hard and soft rocks, as encountered in a lateritic environment. This paper focuses on the determination of spectral characteristics of laterite drill-cores in the visible to short wave infrared spectral range. One of the most important prerequisites is to study the influence of the surface roughness effect on infra-red spectroscopy analyses. For this purpose, four different rock samples: breccia, sandstones, granite and peridotite, each at five surface states have been considered: as-drilled, as-sawn, polished at 6 μm, polished at 0.25 μm and crushed to powder. The reflectance spectra have been acquired with an ASD Fieldspec 3® spectroradiometer with a contact probe at a sampling surface of 1.76 cm 2 , allowing a spectral analysis at wavelengths from 350 up to 2500 nm. The powder spectrum of breccia presents a higher reflectance than the four other spectra from the same material but weak absorption features. The as-sawn sample presents the higher absorption depth, followed by as-drilled sample and the two polished samples (figure 1). At wavelength 2219 nanometers, a peak of absorption is present. The presence of clay minerals is assumed like illite/sericite with more or less smectite, due to the relatively deep water absorption around wavelength 1900 nanometers.

In order to evaluate the instrumental parameters for the combined on-line-on-mine-real-time expert system SOLSA (http://www.solsa-mining.eu), portable and laboratory analyses were carried out on coarse granite, sandstone, serpentinized harzburgite and siliceous breccia. Each sample was studied at 5 different surface roughnesses (sonic or diamond drilled, cut, polished at 6 mu m and 0.25 mu m, sample powders). X-ray diffraction (XRD), portable Infra-Red (pIR) and X-ray-fluorescence (pXRF), and laboratory micro-Raman spectroscopy gave complementary and corroborating results. No major effect on the analyses was noted for the selected surface states. pXRF gave variable results except for the homogeneously serpentinized harzburgite, related to coarse or contrasting grain sizes or pores, small spot size (3 mm) and needs close-to-surface analyses. Portable IR (spot size 1.76 cm(2)) is carried out close to surfaces while Raman spectroscopy (1-2 mu m) is performed at distance. Sampling strategies have to be defined for each lithology. Major challenges for a combined on-line analysis are to adapt the specificities of the techniques to (1) analyse similar surface areas (from 2 cm(2) (pIR) to < mu m (Raman)), (2) smartly combine all the techniques into a single instrument, and (3) develop appropriate databases to reach a reliable "real-time" outcome results, which can be used for more precise geomodeling, and to rapidly define exploration and beneficiation parameters.

Efficient data collection, analysis and preservation are needed to accomplish adequate business decision making. Long-lasting and sustainable business operations, such as mining, add extra requirements to this process: data must be reliably preserved over periods that are longer than that of a typical software life-cycle. These concerns are of special importance for the combined on-line-on-mine-real-time expert system SOLSA (http://www.solsa-mining.eu/) that will produce data not only for immediate industrial utilization, but also for the possible scientific reuse. We thus applied the experience of scientific data publishing to provide efficient, reliable, long term archival data storage. REAL TIME MINING Conference on Innovation on Raw Material Extraction Amsterdam 2017 142 Crystallography, a field covering one of the methods used in the SOLSA expert system, has long traditions of archiving and disseminating crystallographic data. To that end, the Crystallographic Interchange Framework (CIF, [1]) was developed and is maintained by the International Union of Crystallography (IUCr). This framework provides rich means for describing crystal structures and crystallographic experiments in an unambiguous, humanand machinereadable way, in a standard that is independent of the underlying data storage technology. The Crystallography Open Database (COD, [2]) has been successfully using the CIF framework to maintain its open-access crystallographic data collection for over a decade [3,4]. Since the CIF framework is extensible it is possible to use it for other branches of knowledge. The SOLSA system will generate data using different methods of material identification: XRF, XRD, Raman, IR and DRIFT spectroscopy. For XRD, the CIF is usable out-of-the-box, since we can rely on extensive data definition dictionaries (ontologies) developed by the IUCr and the crystallographic community. For spectroscopic techniques such dictionaries, to our best knowledge, do not exist; thus, the SOLSA team is developing CIF dictionaries for spectroscopic techniques to be used in the SOLSA expert system. All dictionaries will be published under liberal license and communities are encourage to join the development, reuse and extend the dictionaries where necessary. These dictionaries will enable access to open data generated by SOLSA by all interested parties. The use of the common CIF framework will ensure smooth data exchange among SOLSA partners and seamless data publication from the SOLSA project.

The SOLSA project (www.solsa-mining.eu) aims to develop an on-line-on-mine expert system coupling sonic drilling, chemical and mineralogical analyses and data treatment. In a first place, this expert system is planned for lateritic profiles of New Caledonia, known to held nickel. The latter is found in two forms in these profiles. First, nickel can be adsorbed on the surface or inserted in the structure of goethite (α-FeOOH) present in the limonites and saprolites. Second, Ni may substitute Mg in different silicates of saprolite, like in garnierite, known to be nickel-rich and corresponding to a mixture of phyllosilicates usually occurring as vein or porosity filling. The SOLSA system will combine several analytical techniques, such as XRD, XRF, Raman spectroscopy, RGB or hyperspectral, and the data collected will be compared to an internal library in order to identify the several minerals present in the lateritic profiles. Therefore, the elaboration of a comprehensive library, taking into account the influence of chemistry on the different signals, is mandatory. Thus, our study focuses on the evolution of the hyperspectral signal (400-2500 nm) with the quantity of nickel for several Ni-bearing silicates present in the lateritic profile. Among the results, nickel influences the behaviour of the doublet in the 1380-1405 nm region

Nickel concentrations resulting from the weathering of ultrabasic rocks may lead to the formation of saprolitic ore where the garnierite may occur. This latter is mainly found in veins and fissures within the saprolite and can host 20 to 40 wt% Ni (Soler et al., 2008). Garnierite is characterized by a mixture of various nickel-bearing magnesium-phyllosilicates, such as serpentine, talc or sepiolite, which form a series of solid solution by Mg-Ni substitution (Gleeson et al., 2004). In the context of the SOLSA project (www.solsa-mining.eu), which aims to develop an on-mine-on-line expert system for industrial applications by combining sonic drilling, chemical, mineralogical characterizations and data treatment, the analysis of nickel-rich phases (e.g. garnierite, smectite, serpentine) has been studied in view of their interests for nickel exploration in lateritic profiles. Thus, in order to define characteristic signals of garnierite, a set of samples representative of the diversity of Ni-bearing clay minerals has been characterized using different analytical techniques, such as X-ray diffraction (XRD), Raman microspectroscopy, scanning electron microscopy (SEM) and electron probe micro-analysis (EPMA). The collected samples are Ni-bearing laterites from New Caledonia and the Dominican Republic. The results obtained show the effect of Ni on the position of certain X-ray diffraction peaks and/or Raman bands. The observed shifts between Ni-poor and Ni-rich phyllosilicate phases are characteristic of the substitution of Mg by Ni in octahedral sites and can be correlated to the amount of Ni (Cathelineau et al., 2015; Baron and Petit, 2016).

The recycling of basic oxygen furnace slag in the steelmaking process is currently limited by its phosphorus content. Phosphorus is known to induce remarkable phase segregation in the slag microstructure and is only present in phases belonging to the C2S–C3P solid solution, the iron-containing phases being left free of phosphorus. The mechanism of phosphorus insertion into calcium silicate structures was studied by a combination of TEM, XRD and 29Si and 31P solid-state NMR. Upon P2O5 addition, [PO4]3− units are incorporated into the dicalcium silicate structure by substituting [SiO4]4− groups, charge balance being maintained by creation of calcium vacancies. This substitution leads to a stabilization of the β- and α-Ca2SiO4 phases at room temperature and results in the formation of more polymerized calcium silicate secondary phases. The obtained P-substituted α-Ca2SiO4 compounds belong to the Ca2−x/2Si1−xPxO4 solid solution and exhibit lattice parameters similar to those of the calcium phosphosilicate Ca15(PO4)2(SiO4)6 phase.