Customized Spectral Libraries for Effective Mineral Exploration: Mining National Mineral Collections

Percival, John A.; Bosman, Sean; Potter, E G; Peter, Jan M.; Laudadio, A B; Abraham, Ashley C.; Shiley, Daniel A.; Sherry, Chris

doi:10.1346/ccmn.2018.064103

Cited by 22 publications

(5 citation statements)

References 34 publications

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“…It is presumed that this difference in depth in the absorptions between the standard spectrum and the sample is due to chemical treatment, especially in the content of surface and hydroxylic water. Regarding the absorption characteristics of the untreated sample (natural rock chip), they coincide in wavelength and absorption depth with the allophane standard sample and have a 90 % similarity (36). With the TSG, the reflectance images were adjusted with bentonite patterns (Figure 3b) and two more for kaolinite and vermiculite.…”

Section: -Chemical Analysis (Xrf) and Results Of Adsorption And Desor...mentioning

confidence: 99%

Nanometric and Thermogravimetric Evaluation of Volcanic Clays With Industrial Interest (Ecuador)

CERON,

Ceron,

Loria

et al. 2023

Preprint

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Ecuador has 4000 Km2 of volcanic nanoclay reserves that could be industrialized. An immediate application is to modify the local AC-20 asphalt with this aggregate. This resource was characterized with FTIR, XRD, FRX, SEM, BET, Laser Granulometry, SPECMIN, TSG, TGA, DTG, DSC and Atmospheric Adsorption. FTIR showed vibration peaks Si and Al. X-ray diffraction indicated the presence of silicates and alumina, BET measured particle size (30 to 250 nm), and the SSA property measured the specific surface area (280.38 m2/g). Chip rock (natural clay) was treated with H2O2 or NaOH or NH3 and evaluated with SPECMIN -TSG obtaining spectra close to vermiculite, allophane and bentonite minerals. At 1000 °C additional samples were calcined in Thermogravimetry (TGA), Differential Thermogravimetry (DTG), Differential Thermal Analysis (DCS), with mass loss around 40%, corresponding to organic matter, hydroxyl (OH) and destruction of its structure with spicule formation at 956 °C. With the DSC there were endothermic and exothermic manifestations. The Si/Al layers would have micro and meso porosity, it was also found to be a nanoparticulate material, with high adsorption capacity. At temperatures above 350 °C, its structure collapsed. Thus, this synthesized nanoclay will be used as an additive to form new materials.

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Section: -Chemical Analysis (Xrf) and Results Of Adsorption And Desor...mentioning

confidence: 99%

Nanometric and Thermogravimetric Evaluation of Volcanic Clays With Industrial Interest (Ecuador)

CERON,

Ceron,

Loria

et al. 2023

Preprint

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“…The Council of The NMC produced by Geological Survey of Canada contains more than 100,000 minerals. 21 Although spectral libraries of different minerals produced in laboratories have been widely used in mineral and rock identifications, some natural heterogenies existed in various minerals and associated spectral mixing possibly still have unwanted effects on the image processing results. 22,23 Field spectroscopy is evolving as a robust technique to overcome this issue specially Fig.…”

Section: Spectral Properties Of Different Mineralsmentioning

confidence: 99%

Hyperspectral remote sensing in lithological mapping, mineral exploration, and environmental geology: an updated review

Peyghambari

Zhang

2021

J. Appl. Rem. Sens.

132

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Hyperspectral imaging has been used in a variety of geological applications since its advent in the 1970s. In the last few decades, different techniques have been developed by geologists to analyze hyperspectral data in order to quantitatively extract geological information from the high-spectral-resolution remote sensing images. We attempt to review and update various steps of the techniques used in geological information extraction, such as lithological and mineralogical mapping, ore exploration, and environmental geology. The steps include atmospheric correction, dimensionality processing, endmember extraction, and image classification. It is identified that per-pixel and subpixel image classifiers can generate accurate alteration mineral maps. Producing geological maps of different surface materials including minerals and rocks is one of the most important geological applications. The hyperspectral images classification methods demonstrate the potential for being used as a main tool in the mining industry and environmental geology. To exemplify the potential, we also include a few case studies of different geological applications.

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“…Chlorites have been empirically classified as Mg-rich chlorite when their absorption features vary between 2240 and 2249 nm and 2320 and 2329 nm, intermediate (or Mg-Fe) when they vary between 2250 and 2255 nm and 2330 and 2349 nm, and Fe-rich when they vary between 2256 and 2265 nm and 2350 and 2360 nm [6,8,34]. Al-rich dioctahedral chlorites, such as sudoite (Al), have a well-developed 2200 nm feature in addition to the 2250 nm (shallow) and 2340 nm (deep) features, due to their high Al content (Figure 1; [8,35,36]).…”

Section: Chlorite Groupmentioning

confidence: 99%

Mineralogy, Mineral Chemistry and SWIR Spectral Reflectance of Chlorite and White Mica

2021

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Hyperspectral reflectance has the potential to provide rapid and low-cost mineralogical and chemical information that can be used to vector in mineral systems. However, the spectral signature of white mica and chlorite, despite numerous studies, is not fully understood. In this study, we review the mineralogy and chemistry of different white mica and chlorite types and investigate what mineralogical and chemical changes are responsible for the apparent shifts in the shortwave infrared (SWIR) spectroscopic absorption features. We demonstrate that the spectral signature of white mica is more complex than previously documented and is influenced by the Tschermak substitution, as well as the sum of interlayer cations. We show that an increase in the interlayer deficiencies towards illite is associated with a change from steep to shallow slopes between the wavelength position of the 2200 nm feature (2200 W) and Mg, Al(VI) and Si. These changes in slope imply that white micas with different elemental chemistry may be associated with the same 2200 W values and vice versa, contrary to traditional interpretation. We recommend that traditional interpretations should only be used in true white mica with sum interlayer cations (I) > 0.95. The spectral signature of trioctahedral chlorite (clinochlore, sheridanite, chamosite and ripidolite) record similar spectral relationships to those observed in previous studies. However, dioctahedral Al-rich chlorite (sudoite, cookeite and donbassite) has a different spectral response with Mg increasing with 2250 W, which is the opposite of traditional trioctahedral chlorite spectral interpretation. In addition, it was shown that dioctahedral chlorite has a 2200 W absorption feature that may introduce erroneous spectral interpretations of white mica and chlorite mixtures. Therefore, care should be used when interpreting the spectral signature of chlorite. We recommend that spectral studies should be complemented with electron microprobe analyses on a subset of at least 30 samples to identify the type of muscovite and chlorite. This will allow the sum I of white mica to be obtained, as well as estimate the slope of 2200 W absorption trends with Mg, Al(vi), and Si. Preliminary probe data will allow more accurate spectral interpretations and allow the user to understand the limitations in their hyperspectral datasets.

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Customized Spectral Libraries for Effective Mineral Exploration: Mining National Mineral Collections

Cited by 22 publications

References 34 publications

Nanometric and Thermogravimetric Evaluation of Volcanic Clays With Industrial Interest (Ecuador)

Nanometric and Thermogravimetric Evaluation of Volcanic Clays With Industrial Interest (Ecuador)

Hyperspectral remote sensing in lithological mapping, mineral exploration, and environmental geology: an updated review

Mineralogy, Mineral Chemistry and SWIR Spectral Reflectance of Chlorite and White Mica

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