Sample records for exinite

  1. Characterization of pyrolysates from maceral components of Tarim coals in closed system experiments and implications to natural gas generation

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    Liu, Q.Y.; Liu, W.H.; Dai, J.X. [PetroChina, Beijing (China)


    The macerals vitrinite, exinite, fusinite, and semi-fusinite from low-maturity coal (VR{sub r} = 0.40%) of the Manjiaer sag, Tarim Basin were isolated and subjected to isothermal pyrolysis in a sealed stainless steel reactor at temperatures ranging from 250 to 550{sup o}C in 50{sup o}C intervals for a duration of 72 h. Gas yields, chemical and isotopic compositions vary significantly for the different coal macerals. Total gas yields (predominantly CH4 and CO{sub 2}) from exinite and vitrinite are much higher than those from fusinite and semi-fusinite. Carbon dioxide generated from exinite is slightly enriched in {sup 13}C as compared to CO{sub 2} produced from vitrinite. Methane produced from exinite tends to be isotopically lighter than methane generated from inertinite. Interestingly, the {delta} {sup 13}C(CH4) values of all macerals show a similar evolution pattern with temperature - the initial gas is isotopically heavy, then becomes lighter at moderate temperatures, and finally becomes heavier again. This may be an indication of isotopic heterogeneity within the coal precursors. Hydrocarbon potential of coal closely depends on the maceral composition. Exinite shows the highest hydrocarbon generation potential followed by vitrinite, while inertinite has only a poor hydrocarbon potential. The Pr/Ph ratio varies irregularly through catagenesis.

  2. Thermally excited multiplet states in macerals separated from bituminous coal (United States)

    Wieckowski; Pilawa; Swiatkowska; Wojtowicz; Slowik; Lewandowski


    Electron paramagnetic resonance searches of thermally excited multiplet states in macerals, exinite, vitrinite, and inertinite of Polish medium-rank coal (85.6 wt% C), were performed. Numerical analysis of lineshape indicates a multicomponent structure of the EPR spectra of macerals heated at 300 degrees and 650 degrees C. EPR spectra of exinite and vitrinite are a superposition of broad Gauss, broad Lorentz (Lorentz 1), and narrow Lorentz (Lorentz 3) lines. Two narrow Lorentz (Lorentz 2 and Lorentz 3) lines were observed in the resonance absorption curves of inertinite. The influence of the measuring temperature (100-300 K) on the EPR lines of the macerals was also studied. The experimentally obtained temperature dependence of the EPR line intensities were fitted by the theoretical functions characteristic for paramagnetic centers with ground doublet state (S = 12) and paramagnetic centers with thermally excited triplet (S = 1) and quadruplet (S = 32) states. Thermally excited multiplet states were found in exinite and vitrinite. Both paramagnetic centers with doublet ground state (S = 12) and paramagnetic centers with thermally excited states, probably quadruplet states (S = 32), exist in the group of paramagnetic centers of exinite and vitrinite with the broad Lorentz 1 lines. Intensities (I) of the broad Gauss and the narrow Lorentz 3 lines of exinite and vitrinite changes with temperature according to the Curie law (I = C/T). The existence of thermally excited multiplet states was not stated for inertinite. The two groups of paramagnetic centers of inertinite with Lorentz 2 and Lorentz 3 lines obey the Curie law. Copyright 2000 Academic Press.

  3. Effects of petrographic composition and sulphur in liquefaction of Spanish lignites

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    Cebolla, V.L.; Martinez, M.T.; Miranda, J.L.; Fernandez, I. (Instituto de Carboquimica, Zaragoza (Spain))


    The behaviour in hydroliquefaction (H{sub 2}), tetralin, 400{degree}C of four Spanish lignites with different petrographic composition and a similar ash content was studied and the nature of the derived oils was evaluated. Vitrinite and/or vitrinite plus exinite contents and percentages of total and organic sulphur correlate with conversion yields. Macerals composition does not appear to influence the nature of the derived oils. 22 refs., 3 figs., 8 tabs.

  4. Prediction of coal grindability based on petrography, proximate and ultimate analysis using multiple regression and artificial neural network models

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    Chelgani, S. Chehreh; Jorjani, E.; Mesroghli, Sh.; Bagherieh, A.H. [Department of Mining Engineering, Research and Science Campus, Islamic Azad University, Poonak, Hesarak Tehran (Iran); Hower, James C. [Center for Applied Energy Research, University of Kentucky, 2540 Research Park Drive, Lexington, KY 40511 (United States)


    The effects of proximate and ultimate analysis, maceral content, and coal rank (R{sub max}) for a wide range of Kentucky coal samples from calorific value of 4320 to 14960 (BTU/lb) (10.05 to 34.80 MJ/kg) on Hardgrove Grindability Index (HGI) have been investigated by multivariable regression and artificial neural network methods (ANN). The stepwise least square mathematical method shows that the relationship between (a) Moisture, ash, volatile matter, and total sulfur; (b) ln (total sulfur), hydrogen, ash, ln ((oxygen + nitrogen)/carbon) and moisture; (c) ln (exinite), semifusinite, micrinite, macrinite, resinite, and R{sub max} input sets with HGI in linear condition can achieve the correlation coefficients (R{sup 2}) of 0.77, 0.75, and 0.81, respectively. The ANN, which adequately recognized the characteristics of the coal samples, can predict HGI with correlation coefficients of 0.89, 0.89 and 0.95 respectively in testing process. It was determined that ln (exinite), semifusinite, micrinite, macrinite, resinite, and R{sub max} can be used as the best predictor for the estimation of HGI on multivariable regression (R{sup 2} = 0.81) and also artificial neural network methods (R{sup 2} = 0.95). The ANN based prediction method, as used in this paper, can be further employed as a reliable and accurate method, in the hardgrove grindability index prediction. (author)

  5. Coal petrology and genesis of Jurassic coal in the Ordos Basin, China

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    Weihua Ao


    physical conditions so that pore water can maintain a long-term state of oxidation, circulation and connection to the coal. So coal components remain in an oxidation environment for a long time. Conversely, in the basin center, lacustrine facies developed and peat was rapidly covered by mudstone after burial and subsequent coal beds rapidly entered a reducing environment. As a result, abundant gelatification occurred and the vitrinite content increased. Exinite often accumulated in a specific position in the coal bed. Although the average exinite content is not high on the whole, it does significantly contribute to the total hydrocarbon generation. The exinite content has been underestimated, especially the amorphous bituminous fluid and its importance is emphasized here. The reason is that the fluid flows easily into fusinite which has strong rigidity, or flows into some fissures, where it is commonly neglected.

  6. Relationships between Organic Material and Thermal Maturity Derived from Coal and C-Shale Samples

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    Louis L. Tsai


    Full Text Available The purpose of this study is to characterize the relationship between organic material and thermal maturity during the process of evaluation of hydrocarbon potential. Samples studied include Miocene high volatile bituminous coal and coaly shale collected from outcrops and exploration wells in Hsinchu-Miaoli area, NW Taiwan, density centrifuge separated macerals, bituminous coal and anthracite from China, in addition toWoodford and Green River oil shale from the United States. Maceral composition analysis, elemental analysis, vitrinite reflectance measurement and Rock-Eval pyrolysis were performed for evaluation. The results of study show that: 1 coal samples from the Shiti Formation (middle Miocene exhibit more vitrinite and less mineral matter contents than samples from the Nanchuang Formation (upper Miocene; H is increased in exinite-enriched maceral mixtures with density < 1.25 g cm-3, after density centrifuge separation. 2 A positive linear correlation between Tmax and Ro illustrates both Rock-Eval pyrolysis and vitrinite reflectance can be used as indicators of thermal maturity. 3 From the plot of H/C ratio vs. vitrinite reflectance, even though the depositional environments were different in Taiwan and China, their organic micelles exhibit a similar trend in the process of thermal maturation. As a whole, the curve has a turning point at Ro = 0.5 and H/C = 0.1 (atomic ratio 1.2 in this study. 4 Arather good correlation between S2 and TOC of samples studied indicates the contribution of S2 from TOC. 5 The highest HI occurred in certain maturities (Tmax and Ro of samples studied, and not in the stages of less maturity or over-maturity. 6 Two different linear trends were observed in the cross plot of S1 vs. S2. Field outcropped shale or C-shale exhibits a steeper slope compared to that of coal samples which can be attributed to the compositional difference in their organic material. 7 Arather strong positive correlation for H vs. S2

  7. Studies of relationship between petrography and elemental analysis with grindability for Kentucky coals

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    E. Jorjani; James C. Hower; S. Chehreh Chelgani; Mohsen A. Shirazi; S. Mesroghli [Islamic Azad University, Tehran (Iran). Department of Mining Engineering


    The effects of macerals, ash, elemental analysis and moisture of wide range of Kentucky coal samples from calorific value of 23.65-34.68 MJ/kg (10,170-14,910 (BTU/lb)) on Hardgrove Grindability Index (HGI) have been investigated by multivariable regression method. Two sets of input: (a) macerals, ash and moisture (b) macerals, elemental analysis and moisture, were used for the estimation of HGI. The least square mathematical method shows that increase of the TiO{sub 2} and Al{sub 2}O{sub 3} contents in coal can decrease HGI. The higher Fe{sub 2}O{sub 3} content in coal can result in higher HGI. With the increase of micrinite and exinite contents in coal, the HGI has been decreased and higher vitrinite content in coal results in higher HGI. The multivariable studies have shown that input set of macerals, elemental analysis and moisture in non-linear condition can be achieved an acceptable correlation, R = 90.38%, versus R = 87.34% for the input set of macerals, ash and moisture. It is predicted that elemental analysis of coal can be a better representative of mineral matters for the prediction of HGI than ash. 16 refs., 9 figs., 2 tabs.

  8. Depositional Environment of Fine-Grained Sedimentary Rocks of the Sinamar Formation, Muara Bungo, Jambi

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    M. Heri Hermiyanto Zajuli


    Full Text Available DOI: 10.17014/ijog.v8i1.153The research area is situated in the northwestern side of South Sumatra Basin, which is a part of Muara Bungo Regency, Jambi Province. The Oligocene Sinamar Formation consists of shale, claystone, mudstone, sandstone, conglomeratic sandstone, and coal-seam intercalations. This research was focused on fine sedimentary rock of Sinamar Formation, such as shale, claystone, and mudstone. Primary data were collected from SNM boreholes which have depths varying from 75 m up to 200 m, and outcrops that were analyzed by organic petrographic method, gas chromatography-mass spectrometry (GC-MS of normal alkanes including isoprenoids, and sterane. The dominant maceral group is exinite, composed of alginite (3.4 - 18%, and resinite (1.6 - 5.6%, while vitrinite maceral consists of tellocolinite 0.4 - 0.6%, desmocollinite 0.4%, and vitrodetrinite 8.4 - 16.6%. Organic petrography and biomarker analyses show that organic materials of shales were derived from high plants and algae especially Botrycoccus species. Botrycoccus and fresh water fish fossil, found in the shale indicate a lacustrine environment.

  9. Flash pyrolysis of coal, coal maceral, and coal-derived pyrite with on-line characterization of volatile sulfur compounds (United States)

    Chou, I.-Ming; Lake, M.A.; Griffin, R.A.


    A Pyroprobe flash pyrolysis-gas chromatograph equipped with a flame photometric detector was used to study volatile sulfur compounds produced during the thermal decomposition of Illinois coal, coal macerals and coal-derived pyrite. Maximum evolution of volatile organic sulfur compounds from all coal samples occurred at a temperature of approximately 700??C. At this temperature, the evolution of thiophene, its alkyl isomers, and short-chain dialkyl sulfide compounds relative to the evolution of benzothiophene and dibenzothiophene compounds was greater from coal high in organic sulfur than from coal low in organic sulfur. The variation in the evolution of sulfur compounds observed for three separate coal macerals (exinite, vitrinite, and inertinite) was similar to that observed for whole coal samples. However, the variation trend for the macerals was much more pronounced. Decomposition of coal-derived pyrite with the evolution of elemental sulfur was detected at a temperature greater than 700??C. The results of this study indicated that the gas chromotographic profile of the volatile sulfur compounds produced during flash pyrolysis of coals and coal macerals varied as a function of the amount of organic sulfur that occurred in the samples. Characterization of these volatile sulfur compounds provides a better understanding of the behavior of sulfur in coal during the thermolysis process, which could be incorporated in the design for coal cleaning using flash pyrolysis techniques. ?? 1988.

  10. Sapropelite from the Dzikowiec IG borehole section (intrasudetic depression)

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    Nowak, G.J. (Panstwowy Instytut Geologiczny (Poland). Oddzial Dolnoslaski)


    Characterizes the coal deposit in the area of Nowa Ruda (Lower Silesia coal basin) in Poland. Results of the IG 1 exploratory borehole drilled to a depth of 1,800 m at the site of Dzikowiec are given. The lithostratigraphic profile of the borehole, locating the coal seam in 1,279 m depth, is shown. Petrographic and microscopic characteristics of the coal seam, composed of vitrinite, exinite, fusinite and inertinite, are pointed out, as well the sapropelic character of the coal. Due to sporinite domination, the coal is classified as spore cannel. Conclusions on coal genesis are made: the low vitrinite content and spore character prove that organic matter accumulation took place under shallow water. The high amount of syngenetic coal pyrite suggests that accumulation occurred in a neutral or alkaline environment (pH 6.5-8). Besides pyrite, other inorganic components are clay minerals, carbonates and quartz. Petrographic results support the allochthonous origin of the coal deposit. 21 refs.

  11. Study of coal and graphite specimens by means of Raman and cathodoluminescence (United States)

    Kostova, Irena; Tormo, Laura; Crespo-Feo, Elena; Garcia-Guinea, Javier


    The weak luminescence shown by coals has been attributed to accessorial minerals and poly-nuclear aromatic hydrocarbons, such as exinite, vitrinite or inertinite, while the luminescence quenching has been found in asphaltenes produced by coal hydrogenation or in pyridine extracts. Nowadays, the spatial resolution and the improved luminescence efficiency of the modern spectrometers allow some details of the luminescent emission centers to be explained. We have selected museum historical coal specimens with different rank, i.e., peat, lignite, sub-bituminous, bituminous, and anthracite to be analyzed by their spectra from cathodoluminescence probe (CL) of an environmental scanning electron microscopy (ESEM), with an energy dispersive spectrometry analyzer (EDS). Additional analytical controls were also performed by X-ray diffraction (XRD), X-ray fluorescence (XRF) and Raman spectrometries. We conclude that coals may display different luminescence emission features coming from several different sources, as follows: (i) broadband of intense luminescence from polynuclear aromatic hydrocarbons, (ii) weakly visible broadband luminescence attributed to band-tail states caused by variations in the energy gap of individual sp2 carbon clusters, which are different in size and/or shape, (iii) silicate impurities causing the common luminescence peak at 325 nm observed in coals. This peak is due to non-bridging oxygen hole centres (tbnd Sisbnd Orad ) probably generated by precursor Sisbnd Osbnd C species formed by tbnd Sisbnd Orad defects and carbon atoms; (iv) a 710 nm CL emission commonly detected also in wood and ivory, which has been correlated with hydrocarbon groups of chlorophyll or lignine. Coals are very complex rocks, composed by both organic and inorganic phases with variable and complex spectra. More analyses are necessary and carbonaceous standards of graphite, silicon carbide, stuffed carbon silica and diamond at variable experimental conditions have to be

  12. Mass spectrometric and chemometric studies of thermoplastic properties of coals. 1. Chemometry of conventional, solvent swelling and extraction data of coals

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    Marzec, A.; Czajkowska, S.; Moszynski, J.; Schulten, H.-R. (Polish Academy of Sciences, Gliwice (Poland). Inst. of Coal Chemistry)

    Twenty-seven coals from Carboniferous seams in Poland were studied with the aim to find links between thermoplastic properties and chemical characteristics of the coals. Three sets of data were obtained for all the coals: (1) thermoplastic properties measured using the Gieseler plastometer; (2) yields of pyridine extractables and swelling measurements for pyridine residues; (3) ultimate, proximate, and petrographic analyses. The three data sets were evaluated using chemometric techniques with the purpose of looking for significant correlations between all the data. Temperature of softening is a linear regression of pyridine extractables and hydrogen content in coals as well as of swelling data. Temperatures of maximum fluidity and resolidification are correlated with each other and with oxygen, exinite, and moisture contents of the coals as well as with the swelling data. It has been concluded that temperature of softening is a colligative property and indicates a phase transition resulting in an increase of thermal induced mobility of coal material; the energy demand of the transition is dependent on contents of bulk components of coal system that were specified in this study. Temperatures of maximum fluidity and resolidification appear to have the same chemical background; i.e. the temperatures depend on the content of the same structural units or components. However, the means of chemical characterization of coal material used in this study were not capable of identifying them. Volatile matter and petrographic composition showed rather limited value as predictive means for some (T{sub F(max)} and T{sub R}) and no predictive value for the other thermoplastic properties. 20 refs., 1 fig., 5 tabs.

  13. Petrography and rank of the Bhangtar coals, southeastern Bhutan

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    Pareek, H.S. (BH23, Meerut (India))


    In Bhutan, a potential coal deposit is exposed at Bhangtar in the 'landslide zone'. Nineteen coal seams are encountered in this area, and occur in the Lower Gondwana Supergroup preserved in between the Main Boundary Fault and the Thrust. The coal is low in moisture, {lt}1.76%, but the coal cores show moisture values of 3.16%. The ash content is up to 48.87% and increases substantially in the younger seams. The volatile content (on a pure coal basis) ranges from 23.38% to 41.02%. The sulphur content is less than 0.61%. The coals are non-coking. The amount of trace elements in the coal is quite low. The average petrographic composition of the Bhangtar coal is vitrinite - 31%, exinite - 2%, inertinite - 31%, and mineral and shaly matter - 36%, the vitrinite proportion decreases from the older to the younger seams, which are shaly. an age can be assigned to the Bhangtar coal. Based on oil reflectance, the rank of the coal is metalignitous to hypobituminous. The average microlithotype composition of the coal is vitrite - 30%, clarite - 1%, vitrinertite V - 14%, vitrinertite I - 11%, durite - 3%, fusite - 14%, and carbominerite - 27%. Vitrite decreases in proportion towards the younger seams, 'intermediates' show a concomitant increase, while durite and fusite remain constant. Carbonaceous shale contains fragmentary inertinite and vitrinite macerals and is interlayered with micro-bands of shaly coal which is characterised by abundant fragments of fusinite and vitrinite. The coal is very fragile and thus amenable to economic beneficiation. The coal is used as fuel in electric power plants. The Bhangtar coal is characteristically distinct from the Gondwana coals of India in petrography and rank, but correlates petrographically with the Kameng coals of Arunachal Pradesh, India. 18 refs., 4 figs., 8 tabs., 3 plates.

  14. Eo-Oligocene Oil Shales of the Talawi, Lubuktaruk, and Kiliranjao Areas, West Sumatra: Are they potential source rocks?

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    M. Iqbal


    Full Text Available DOI:10.17014/ijog.v1i3.198To anticipate the increasing energy demand, additional data and information covering unconventional fossil fuels such as oil shale must be acquired to promote the usage of alternative energy sources to crude oil. The Talawi and Lubuktaruk regions situated within intra-montane Ombilin Basin, and the Kiliranjao assumed to be a small intra montane basin are occupied by Eo-Oligocene sediments of Sangkarewang and Kiliran Formations, respectively. Field activity, geochemical screening techniques, and organic petrographic analysis, supported by SEM mode, are methods used. Most of the oil shale sequence is typically of an organically rich-succession comprising predominantly well-bedded, laminated and fissile, brownish to dark grey organic-rich shale and mudstone rocks. The exinite macerals within oil shale comprise mainly Pediastrum-lamalginite with minor cutinite, resinite, liptodetrinite, sporinite, bituminite, and rare Botryococcus-telalginite. Therefore; the oil shale deposits can be described as “lamosites”. Minor vitrinite maceral is also recognized. TOC analysis on selected shale samples corresponds to a fair up to excellent category of source rock characterization. The hydrogen index (HI for all samples shows a range of values from 207 - 864, and pyrolysis yield (PY ranges from 2.67 to 79.72 mg HC/g rock. The kerogen is suggested to be of mixed Type II and Type I autochthonous materials such as alginite, with minor allochthonous substances. Oil samples collected appear to be positioned within more oil prone rather than gas prone. Thermal maturity of the oil shales gained from Tmax value and production index (PI tends to show immature to marginally/early mature stage. A consistency in the thermal maturity level results by using both Tmax and vitrinite reflectance value is recognized. On the basis of  SEM analysis, the oil shale has undergone a late eodiagenetic process. Thereby, overall, vitrinite reflectance

  15. Coalbed methane potential and coal characteristics in the Lati region, Berau basin, East Kalimantan

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    Nana Suwarna


    Full Text Available geological research was performed in the Berau Basin, to provide a better understanding on the potential and resources of coalbed methane (CBM in Berau Regency, East Kalimantan Province, particularly in the Lati Coalfield. Field observation conducted in the coalfield, shows that the banded to bright banded Lati coal is dominated by the bright banded one. Petrographically, the coal consists of vitrinite comprising typical telocollinite and desmocollinite; with rare to sparse exinite, and minor inertinite, and mineral matter. Geochemical analysis shows the range of volatile matter content is from 32.65–39.60%, total sulfur from 0.35–3.04%, ash varies between 2.78–14.50%, and moisture from 12.23–19.98%. Vitrinite reflectance values (Rv, varying from 0.42–0.57%, tend to indicate that the Lati coal rank ranges from sub-bituminous B to high volatile bituminous C category, with low ash content in general. Moreover, the coal maturity level, thermally immature to early mature, leads to the assumption that the expected gas present is suggested to be of biogenic origin. The fairly well cleated Lati coal shows cleat orientations trending north - northeastward, perpendicular to nearly oblique to the syncline axis. Furthermore, coal microcleat occurs as open tensional, sub-curved to curved lines microcracks, diagonally to perpendicular to bedding plane, but some are parallel to the bedding plane. An in-situ coal gas calculation tends to indicate a low to moderate methane content level, with a value of 44.20–47.08 scf/t. However, the Q1 plus Q2 calculation exhibits the gas content ranging from 41.69 to 78.71 scf/t. Moreover, total calculated gas in-place of the P, Q, and R Seams =  5.33 m3/t = 191.56 scf/t.    

  16. Recommended procedures and techniques for the petrographic description of bituminous coals (United States)

    Chao, E.C.T.; Minkin, J.A.; Thompson, C.L.


    Modern coal petrology requires rapid and precise description of great numbers of coal core or bench samples in order to acquire the information required to understand and predict vertical and lateral variation of coal quality for correlation with coal-bed thickness, depositional environment, suitability for technological uses, etc. Procedures for coal description vary in accordance with the objectives of the description. To achieve our aim of acquiring the maximum amount of quantitative information within the shortest period of time, we have adopted a combined megascopic-microscopic procedure. Megascopic analysis is used to identify the distinctive lithologies present, and microscopic analysis is required only to describe representative examples of the mixed lithologies observed. This procedure greatly decreases the number of microscopic analyses needed for adequate description of a sample. For quantitative megascopic description of coal microlithotypes, microlithotype assemblages, and lithotypes, we use (V) for vitrite or vitrain, (E) for liptite, (I) for inertite or fusain, (M) for mineral layers or lenses other than iron sulfide, (S) for iron sulfide, and (X1), (X2), etc. for mixed lithologies. Microscopic description is expressed in terms of V representing the vitrinite maceral group, E the exinite group, I the inertinite group, and M mineral components. volume percentages are expressed as subscripts. Thus (V)20(V80E10I5M5)80 indicates a lithotype or assemblage of microlithotypes consisting of 20 vol. % vitrite and 80% of a mixed lithology having a modal maceral composition V80E10I5M5. This bulk composition can alternatively be recalculated and described as V84E8I4M4. To generate these quantitative data rapidly and accurately, we utilize an automated image analysis system (AIAS). Plots of VEIM data on easily constructed ternary diagrams provide readily comprehended illustrations of the range of modal composition of the lithologic units making up a given coal