Automated Mineralogy Research Papers - Academia.edu (original) (raw)

2024, Moroccan Journal of Chemistry

K. Boujounoui (a)* , A. Abidi (b) , A. Bacaoui (a) , K. El Amari (c) , A. Yaacoubi (a) .

2024, Frontiers in Earth Science

2024, Journal of Archaeological Science

The Altar Stone at Stonehenge is a greenish sandstone thought to be of Late Silurian-Devonian ('Old Red Sandstone') age. It is classed as one of the bluestone lithologies which are considered to be exotic to the Salisbury Plain environ, contrasting with the larger sarsen stones, which are a hard, durable silcrete derived from no more than 30km from Stonehenge. It is well established that most of the bluestones are derived from the Mynydd Preseli, in west Wales. However, no Old Red Sandstone rocks crop out in the Preseli; instead a source in the Lower Old Red Sandstone Cosheston Subgroup at Mill Bay, on the shores of Milford Haven, to the south of the Preseli, has been proposed. More recently, on the basis of detailed petrography, a source for the Altar Stone much further to the east, towards the Wales-England border, has been suggested. Quantitative analyses presented here compare data from proposed 2 Stonehenge Altar Stone debris with samples from the Cosheston Subgroup at Mill Bay in west Wales, as well as with a second sandstone type found at Stonehenge which, on palaeontological evidence has been shown to be Lower Palaeozoic in age. The Altar Stone samples have up to 16.7 modal % calcite while the Lower Palaeozoic and Cosheston Subgroup sandstones have less than 0.25 modal %. The Altar Stone also contains up to 3.8 modal % kaolinite and 0.8 modal % barite, minerals that are absent from the other sandstones. Calcite, kaolinite and barite in the Altar Stone samples all occur between the detrital grains and are all thought to be authigenic minerals, which differs markedly with the Cosheston Subgroup and Lower Palaeozoic sandstones. The Cosheston Subgroup sandstone contrasts with the other two sandstone lithologies in having up to 0.7 modal % detrital garnet (<0.08 in both the other two sandstone types). Further differences between the Altar Stone sandstone and the Cosheston Subgroup sandstone are seen when their contained zircons are examined. Not only do they have differing morphologies (size, shape and quality) but U-Pb age dates for the zircons show contrasting populations; the Cosheston Subgroup sample zircon age population is essentially bimodal, with age maxima at 500 and 1500 Ma whilst the Altar Stone zircon population is more diverse, with ages spanning from 472 to 2475 Ma without maxima. Together, all these data confirm that Mill Bay is not the source of the Altar Stone with the abundance of kaolinite in the Altar Stone sample suggesting a source further east than Milford Haven, towards the Wales-England border. The disassociation of the Altar Stone and Milford Haven fully undermines the hypothesis that the bluestones, including the Altar Stone, were transported from west Wales by sea up the Bristol Channel and adds further credence to a totally land-based route, possibly along a natural routeway leading from west Wales to the Severn estuary and beyond. This route, along the valleys followed today by the A40, may well have been significant in prehistory, raising the possibility that the Altar Stone was added en route to the assemblage of Preseli bluestones taken to Stonehenge around or shortly before 3000 BC. Recent strontium isotope analysis of human and animal bones from Stonehenge, dating to the beginning of its first construction stage around 3000 BC, are consistent with having lived in this western region of Britain.

2024, American Mineralogist

Modeling crystal size distributions often requires the extraction of 2D discrete crystal lengths to calculate 3D volumetric equivalences. These apparent lengths are obtained from digital images that exploit different physical and chemical characteristics of samples, and the choice of image type can affect the interpretation of crystal length measurements, thus affecting crystal size distribution modeling. To examine method- and texture-based effects on extracting crystal size distributions, we obtained plagioclase length measurements from two texturally opposing basaltic lava samples from the well-documented Laki fissure eruptions of 1783–1784. Using approaches that consider inherent texture-based limitations of 2D image types, we employed manual tracing and imaging software to extract plagioclase crystal lengths from three types of images: (1) photomicrographs from polarized-light microscopy, (2) backscatter electron images from scanning electron microscopy, and (3) energy-dispersi...

2024, Physicochemical Problems of Mineral Processing

In this paper, the results of a performance evaluation study carried out in a chromite concentration plant are presented. The plant is a typical of the similar kind of gravity concentrators which are not equipped with basic control and measuring devices. Therefore evaluation o f their performance appears to be a difficult task and requires unique methodology. The study commenced with sampling. A week long sampling surveys were repeated twice. First, the data was mass balanced then conventional parameters of equipment efficiency were determined. After detailed evaluation of the performance data, some modifications at the plant operation, i.e. changing screen aperture from 6 trim to 2 mm, limiting capacity for the plant and the possibility of using two rod mills in parallel, were proposed. Their effects on the performance were investigated by using computer simulation techniques. The results show that the performance and capacity could be improved by applying the proposed changes in the flowsheet.

2023, Microscopy and Microanalysis

An innovative multispectral reflected-light microscopy system is able to automatically identify ore minerals by measuring their specular reflectance with non-polarized light in a number of spectral bands, and comparing the values obtained with a reference database. In this way it can provide quantitative mineralogical mapping comparable to that obtained from automated mineralogy systems based on SEM-EDS (Scanning Electron Microscopy with Energy-Dispersive X-Ray Spectroscopy), at a fraction of the cost and with less stringent environmental and operational requirements.

2023, Ore and Energy Resource Geology

The Bear Lodge REE deposit is located in northeastern Wyoming. The Eocene carbonatite dyke and stockwork system intrudes trachytic-phonolitic rocks that contain multiple diatremes. The original magmatic characteristics of the REE-enriched carbonatite complex are strongly overprinted by carbo-hydrothermal and later supergene fluids. These fluids redistributed the REEs and created high variability in the ore mineral assemblage, as well as compositional variability within individual REE mineral species. The REE ore minerals at Bear Lodge can be classified into four types: 1. fluorocarbonates (bastnaesite, parisite, synchysite), 2. phosphates (monazite, xenotime, florencite, rhabdophane, churchite), 3. cerianite, and 4. ancylite. These minerals vary greatly in abundance, grain size, and morphology. REE distribution is heterogeneous throughout the deposit. Variations within a given REE mineral in terms of Ce depletion, Th content, degree of heavier REE enrichment, etc., create difficulties in the initial definition of discrete mineral species (i.e., by X-ray spectra) and their resultant species identification protocols for use in automated mineralogy (QEMSCAN R ○ in this study). Prevalent submicron-scale supergene mineralization result in hybrid spectra from multiple phases. Iterative work in reconciling QEMSCAN R ○ data interpretation with bulk assay, XRD, SEM, and optical petrography data allows for refinement of the protocols to quantify for both ore and gangue minerals. Use of automated mineralogy in the development of complex deposits requires rigorous review of these identification criteria in order to achieve results that can be applied with confidence to resolve mineral processing issues.

2023, Journal of Archaeological Science

2023, Mineral Exploration of Grande Côte Operations placer (Senegal)

Simplified presentation of the results of the investigation on the alteration of iron-titanium oxides of the Grande Côte placer, Senegal. Since 2013, the society Tizir Limited, Eramet’s subsidiary, has been recovering the zircons and the titanium-iron bearing oxides of the Senegal Grande Côte. This placer deposit presents a heterogeneity of mineralogical composition related to the diverse facies of sand and their distribution along the dune system. The purpose of this first course is to characterise the various horizons of sand mineralogically, athwart the study of drilling profiles to examine the evolution of the concentration in heavy minerals, following their locations and depths, and the specificities of these horizons. The second subject broached is the impurity issues in the minerals. A study on the origins and the contents of these anomalies with be realised. To address this issue, several analytical methods have been used, such as scanning electron microscopy (SEM), paired with the QEMSCAN© analyses.

2023

Includes bibliographical references.2018 Spring.Igneous rock textures are directly tied to pre-, syn- and post-eruptive processes that occur throughout the evolution of a melt. One aspect of texture concerns crystal size distributions (CSDs), which are volume-based, individual counts of crystals from a defined volume of rock. CSDs provide insight into the kinetic evolution of igneous rocks. Direct measurements of crystal volumes from rock samples are often impractical, forcing the use of crystal lengths from thin sections as proxies for crystal volumes. We use a combination of manual tracing and automated SEM-based methods to delineate crystal borders while software (ImageJ, CSDSlice and CSDCorrections) addresses direct length acquisition and stereological conversions. Using texturally diverse lava samples, we demonstrate that this hybrid approach 1) preserves the crystal-length accuracy of manually traced phenocrysts while 2) refining groundmass crystal lengths through automated SE...

2023, Frontiers in Earth Science

2022

Depletion of existing orebodies forces the mining industry to have a better understanding on new orebodies in order to have an economical beneficiation. Therefore, traditional evaluation and foreca ...

2022, INTERNATIONAL JOURNAL OF EXPERIMENTAL RESEARCH AND REVIEW

Schizodactylus monstrosus (Drury) is an Orthoptera belongs to the family Schizodactylidae. Previously although various works has been done on burrowing behavior of the species Schizodactylus monstrosus, our investigation unfolds some new facts about their burrowing behavior. Through this paper we also focus on some anthropogenic threats that causes decline in their population vigorously.

2022, Frontiers in Earth Science

The analysis of archaeological ceramics has rapidly evolved over the last decades by the application of new analytical techniques. An emerging analytical proposal to fully characterise archaeological ceramics using automated SEM mineralogy is presented. A case study is provided of sets of ceramics from the San Pedro de Atacama oases in the Atacama Desert, northern Chile. Ceramic fragments of different typologies (i.e., Los Morros, Loa Café Alisado and San Pedro Negro Pulido) found in the Ghatchi archaeological sites are analysed. Our results include automated mineralogical maps, which are used to define the components that form the ceramic pastes, i.e., clay matrix and non-plastic inclusions, as well as grain size and mineral abundance information. We show that the pastes that define the studied ceramic types are more complex than previously suggested. The overall composition for these pastes corresponds to clay mineral-rich matrices containing non-plastic inclusions, such as mineral grains, crushed ceramic fragments, and sedimentary to igneous rock fragments, that may vary in composition, size, and abundance among the studied ceramic types. This mineralogical information allows us to discuss possible sources of raw materials by comparing these paste components with geological information. Here we interpret Los Morros and Loa Café Alisado as foreign ceramic types to Ghatchi, whereas the San Pedro Negro Pulido fragments found in this site agree well with the pottery paste recipe typically recognised in the San Pedro de Atacama oases. The petrographic-approach employed here supports the automated SEM mineralogy as a valid option for archaeometric studies of ceramic pastes since includes precise quantitative data formulated from the chemical composition of each component of the paste, which may provide valuable evidence into raw materials and technological styles.

2022, American Mineralogist

Plagioclase textures were investigated in the products of the voluminous 1783-1784 CE Laki eruption from the Eastern Volcanic Zone (EVZ) of Iceland to establish whether mush disaggregation occurred solely at the onset of the eight-month eruption or throughout its whole duration. Phase proportions and plagioclase size distributions were determined using standard optical and manual techniques as well as automated approaches based on Quantitative Evaluation of Minerals by SCANing electron microscopy (QEMSCAN). Based on optical microscopy and the explicit combination of textural and compositional information in QEMSCAN images, plagioclase crystals were divided into two populations: small (<0.5 mm long), high-aspect ratio (length/width >4) microcrysts with low-anorthite (<An 80) cores; and large (>0.5 mm long), low-aspect ratio (length/width = 2-3) macrocrysts with high-anorthite (An 84-An 92) cores. Small microcrysts grew from their carrier liquid during the final phase of pre-eruptive crystallization while large macrocrysts, which are out of geochemical equilibrium with their carrier liquids, were entrained from crystal mushes. Changes in phase proportions and plagioclase size distributions between eruptive episodes demonstrate that macrocryst entrainment efficiency varied substantially during the eruption; material erupted in later episodes contain proportionally more mush-derived material. Using stereologically corrected plagioclase size distributions, we estimate that the pre-eruptive residence times of microcrysts in the Laki carrier liquid were probably of the order of 2-20 days. Because microcryst crystallization was concurrent with macrocryst rim growth, these day-to-week residence times also indicate that macrocryst entrainment occurred on much shorter timescales than the eruption's eight-month duration. In line with constraints from independent geochronometers, macrocryst entrainment and mush disaggregation thus appears to have continued throughout the eruption. Magmas were assembled on an episode by episode basis, and the volume of eruptible magma in the plumbing system at any given time was probably closer to 1-2 km 3 than the final erupted volume of 15.1 km 3 .

2019, Geometallurgy

Increasing competition in the minerais industry and fluctuating coramodity prices require new ways of saving energy, lime, and general operational costs. A good understanding of physical processing or pre-processing streams that can potentially cut these costs requires detailed analyses of chemical and physical behaviours and processing responses during rainera]. processing. It is very useful to perform a detailed mineralogical and micro-textural characterization of materials (ore, tailings, and waste) that addresses, among other parameters, particle and grain sizes, as well as particle densifies. The choice and/or corabination of the 'best' processing approaches is crucial for processing efficiencies, and can be established and verified by using automated mineralogy with the associated software. A sample of low-grade iron ore from El Volcan, Mexico, serves as an example to demonstrate in a step-by-step approach how QEMSCAN® analyses provide processing information. Elements under consideration include iron, phosphorus, and sulphur.

2019, Geochemical cycle of Ni, Nancy

Mineral quantifications are challenging on Ni-laterites: XRD analyses provide useful information on mineral species present in samples but with limitations in the precise quantification of complex mineral assemblages containing different particle and grain sizes. The quantification of clay mineral rich samples presents particular challenges as described by Pevear (1989) and Reynolds (1989). Automated-SEM systems including MLA, Qemscan, and TIMA show also limitations with respect to the distinction of Mg-silicates with close chemical compositions (olivine, serpentine, talc, nontronite, saponite, pyroxene,…). MLA and Qemscan, and the associated software, provide analytical results as count proportions acquired by their respective detectors. These results are presented as element wt%. It should be noted, though, that these results are far from precise and need to be laboriously calibrated and converted in order to ascertain precise element wt% information that are necessary to calculate a structural formula of a mineral. The Mineralogic system allows very fast EDS analyses that provide element and oxide analyses that are acquired from Zeiss SEM analyses and are presented as precise element and oxide wt%. This Mineralogic methodology is a step change to methods employed by QMESCAN, MLA and TIMA. Mineralogic allows for each acquired EDS spectrum to have a matrix correction and peak deconvolution applied before a spectrum quantification. This methodology thus allows for accurate and precise elements quantification, which is subsequently classified using the designed mineral library. In contrast to MLA and Qemscan systems, Mineralogic data can be directly used to establish precise phase compositions, structural formulae, and to even distinguish mineral phases of very similar chemical compositions. The Mineralogic system enables the user to group mineral populations of minor chemical variation. The distinction and quantification of clay minerals and minerals that are grouped within the smectite group is only one field of application. An extensive database is currently under construction that allows a high-precision identification and distinction of minerals including those that were hitherto regarded as problematic with respect to their identification and, even more, quantifications.