The Experts below are selected from a list of 123 Experts worldwide ranked by ideXlab platform
Maria Mastalerz - One of the best experts on this subject based on the ideXlab platform.
-
neutron scattering study of vitrinite insights into sub micrometer inclusions in north american carboniferous coals of Bituminous Rank
International Journal of Coal Geology, 2018Co-Authors: Andrzej P Radlinski, Maria MastalerzAbstract:Abstract Results of SANS and USANS measurements performed on a series of six vitrinite samples having vitrinite reflectance (Ro) values ranging from 0.55% (high volatile Bituminous Rank) to 1.28% (medium volatile Bituminous Rank) were analyzed. Experimental data were acquired for two sample forms: platelets cut parallel to the bedding and pellets made up of randomly oriented, nearly-monodisperse particles. Numerical analysis indicates the presence of sub-micron sized inclusions embedded in the organic matrix. For the lowest-Rank vitrinites, the dominating inclusions are monodisperse are ~ 7–12 nm in diameter, and have concentrations of the order of 1017 cm− 3. Their shape is anisotropic, with the surface-to-volume ratio about three times larger than for a solid sphere. The higher-Rank vitrinites contain much larger monodisperse inclusions having diameters of ~ 50 nm, concentrations of ~ 1014 cm− 3, large surface-to-volume ratios, and fuzzy interfaces with the organic matrix. Inclusions of a similar size and concentration are also present in the lowest-Rank sample, but are much less frequent than the small inclusions. We provisionally interpret those objects as inclusions of mineral matter, most likely associated with original plant material. The internal specific surface area (SSA) calculated for the small mineral matter inclusions is ~ 100 m2/cm3 and for the large inclusions ~ 2 m2/cm3.
-
maceral controls on porosity characteristics of lithotypes of pennsylvanian high volatile Bituminous coal example from the illinois basin
International Journal of Coal Geology, 2017Co-Authors: Juan Teng, Maria Mastalerz, Labraun HamptonAbstract:Abstract Porosity characteristics of vitrain, clarain, durain, and fusain lithotypes of the Springfield Coal Member of the Petersburg Formation and the Danville and Hymera Coal Members of the Dugger Formation from the Illinois Basin were investigated with a special emphasis on the control of coal macerals on pore-size distribution. These Pennsylvanian coals are of high volatile Bituminous Rank and have vitrinite reflectance ranging from 0.51 to 0.60%. The lithotypes studied show decreasing values of Brunauer-Emmett-Teller surface area, and micro- and mesopore volumes from vitrain through clarain and durain to fusain. Within the mesopore size range, vitrain and clarain are dominated by pore-size widths of 4 to 10 nm, whereas durain and fusain have more volume for pores larger than 20 nm. In contrast to mesopores, micropore sizes are very similar for all lithotypes, averaging 1.37 to 1.39 nm. In addition to differences among lithotypes, there are significant differences in pore characteristics among the three coals studied, with largest surface areas and pore volumes documented for the Hymera, followed by the Danville and the Springfield. A strong relationship exists between surface area, mesoporosity, and microporosity and maceral composition, with vitrinite having a very strong positive correlation, liptinite having a weak positive correlation, and inertinite having a strong negative correlation. Negative correlations of total porosity with vitrinite and liptinite and positive correlations with inertinite suggest that among the maceral groups, pores in inertinite contribute most to the total porosity. The Fourier transform infrared spectrometry technique demonstrates that fusains from the three coals studied have higher aromaticity and a higher degree of aromatic ring condensation and lower hydrocarbon potential than the other lithotypes, whereas chemical differences between vitrain, clarain, and durain are less distinct. In addition, there is a relationship between aromaticity of the lithotypes and surface area and mesopore and micropore volumes.
-
microanalysis of barkinite from chinese coals of high volatile Bituminous Rank
International Journal of Coal Geology, 2015Co-Authors: Maria Mastalerz, James C. Hower, Yanyan ChenAbstract:Abstract Permian high volatile Bituminous barkinite-rich coal from China has been evaluated petrographically and analyzed by electron microprobe and micro-FTIR techniques. The analyzed samples varied in vitrinite reflectance from 0.65% to 0.73%, and the corresponding reflectance of barkinite ranged from 0.19% to 0.23%. Compared to the associated vitrinite, barkinite had a higher carbon and lower oxygen content in all samples. It had stronger aliphatic CHx absorbance at 2800–3000 and 1450–1460 cm− 1 and less intense both aromatic C = C ring stretching vibration at ~ 1600 cm− 1 and aromatic CHx out-of-plane deformation at 700–900 cm− 1. Micro-FTIR revealed large variations in the aliphatic group intensities within barkinite, suggesting its varying oil generation potential. Air oxidation of barkinite over a 6-month period resulted in rapid consumption of aliphatic groups and the formation of oxygenated functional groups.
-
Variations in pore characteristics in high volatile Bituminous coals: Implications for coal bed gas content
International Journal of Coal Geology, 2008Co-Authors: Maria Mastalerz, Agnieszka Drobniak, Dariusz Strąpoć, Wilfrido Solano Acosta, John A. RuppAbstract:Abstract The Seelyville Coal Member of the Linton Formation (Pennsylvanian) in Indiana was studied to: 1) understand variations in pore characteristics within a coal seam at a single location and compare these variations with changes occurring between the same coal at different locations, 2) elaborate on the influence of mineral-matter and maceral composition on mesopore and micropore characteristics, and 3) discuss implications of these variations for coal bed gas content. The coal is high volatile Bituminous Rank with R 0 ranging from 0.57% to 0.60%. BET specific surface areas (determined by nitrogen adsorption) of the coals samples studied range from 1.8 to 22.9 m 2 /g, BJH adsorption mesopore volumes from 0.0041 to 0.0339 cm 3 /g, and micropore volumes (determined by carbon dioxide adsorption) from 0.0315 to 0.0540 cm 3 /g. The coals that had the largest specific surface areas and largest mesopore volumes occur at the shallowest depths, whereas the smallest values for these two parameters occur in the deepest coals. Micropore volumes, in contrast, are not depth-dependent. In the coal samples examined for this study, mineral-matter content influenced both specific surface area as well as mesopore and micropore volumes. It is especially clear in the case of micropores, where an increase in mineral-matter content parallels the decrease of micropore volume of the coal. No obvious relationships were observed between the total vitrinite content and pore characteristics but, after splitting vitrinite into individual macerals, we see that collotelinite influences both meso- and micropore volume positively, whereas collodetrinite contributes to the reduction of mesopore and micropore volumes. There are large variations in gas content within a single coal at a single location. Because of this variability, the entire thickness of the coal must be desorbed in order to determine gas content reliably and to accurately calculate the level of gas saturation.
-
Application of reflectance micro-Fourier transform infrared analysis to the study of coal macerals: an example from the late jurassic to early cretaceous coals of the Mist Mountain Formation, British Columbia, Canada
International Journal of Coal Geology, 1996Co-Authors: Maria Mastalerz, R. Marc BustinAbstract:Abstract The applicability of the reflectance micro-Fourier Transform infra-red spectroscopy (FTIR) technique for analyzing the distribution of functional groups in coal macerals is discussed. High quality of spectra, comparable to those obtained using other FTIR techniques (KBr pellet and transmission micro-FTIR), indicate this technique can be applied to characterizing functional groups under most conditions. The ease of sample preparation, the potential to analyze large intact samples, and ability to characterize organic matter in areas as small as 20 μm are the main advantages of reflectance micro-FTIR. The quantitative aspects of reflectance micro-FTIR require further study. The exaples from the coal seams of the Mist Mountain Formation, British Columbia show that at high volatile Bituminous Rank, reflectance micro-FTIR provides valuable information on the character of aliphatic chains of vitrinite and liptinite macerals. Because the character of aliphatic chains influences bond disassociation energies, such information is useful from a hydrocarbon generation viewpoint. In medium volatile Bituminous coal liptinite macerals are usually not detectable but this technique can be used to study the degree of oxidation and reactivity of vitrinite and semifusinite.
Colin R. Ward - One of the best experts on this subject based on the ideXlab platform.
-
modes of occurrence and origin of mineral matter in the palaeogene coal no 19 2 from the hunchun coalfield jilin province china
International Journal of Coal Geology, 2018Co-Authors: Shifeng Dai, Colin R. Ward, Wenmu Guo, David French, Victor P Nechaev, Baruch Spiro, Robert B FinkelmanAbstract:Abstract Previous investigations on minerals and elements in coals from northeastern China are very scarce. This paper investigates the mineralogy and geochemistry of the Palaeogene No. 19-2 Coal, parting, and host rocks (roof and floor strata) in the Baliancheng mine, Hunchun Coalfield, Jilin Province, northeastern China. Samples collected from this coalfield were analyzed using low-temperature ashing plus X-ray diffraction analysis, scanning electron microscopy in combination with energy-dispersive X-ray spectrometry, X-ray fluorescence spectrometry, and inductively coupled plasma mass spectrometry. The investigated coal is of subBituminous A to high volatile Bituminous Rank (0.50–0.56% Ro,ran) and has a low sulfur content (0.25% on average). The mineral assemblage of the coal is dominated by kaolinite, illite and expandable clays, and quartz, with a trace of albite. In comparison with low-Rank coals worldwide, the No. 19-2 Coal is enriched in Cs, V, and Mo. The minerals and elements in the coal and its roof and floor strata were mainly derived from the Mesozoic (Jurassic-Lower Cretaceous) intermediate-felsic volcanic rocks surrounding the coal basin. The parting within the coal seam is identified as a tonstein (bed of altered volcanic ash) based on its mineral composition, dominantly of vermicular and book-like kaolinite (plus smectite, high-temperature quartz, sanidine, apatite, and ilmenite), and its persistent distribution throughout the coal deposit. Based on these features and its chemical composition, this tonstein is deduced to have been derived from a Paleogene intermediate-felsic volcanic ash, which is characterized by some adakitic signatures of trace elements, and terrigenous materials. Normalized to the upper continental crust, the investigated samples (particularly the tonstein layer) show positive Eu anomalies inherited from the source rocks. This is in contrast to the coals, host rocks, and tonsteins with intermediate-felsic compositions in many other coal deposits, which are generally characterized by negative Eu anomalies. Geochemical and mineralogical features also indicate that the sedimentary materials of the tonstein, and, to a lesser extent, the floor horizon, were of aeolian origin, but those of most coal plies and roof strata were the result of aqueous deposition.
-
geochemical and mineralogical evidence for a coal hosted uranium deposit in the yili basin xinjiang northwestern china
Ore Geology Reviews, 2015Co-Authors: Shifeng Dai, Colin R. Ward, James C. Hower, Jianye Yang, Huidong Liu, Trent M Garrison, David French, Jennifer M K OkeefeAbstract:Abstract The petrological, geochemical, and mineralogical compositions of the coal-hosted Jurassic uranium ore deposit in the Yili Basin of Xinjiang province, northwestern China, were investigated using optical microscopy and field emission-scanning electron microscopy in conjunction with an energy-dispersive X-ray spectrometer, as well as X-ray powder diffraction, X-ray fluorescence, and inductively coupled plasma mass spectrometry. The Yili coal is of high volatile C/B Bituminous Rank (0.51–0.59% vitrinite reflectance) and has a medium sulfur content (1.32% on average). Fusinite and semifusinite generally dominate the maceral assemblage, which exhibits forms suggesting fire-driven formation of those macerals together with forms suggesting degradation of wood followed by burning. The Yili coals are characterized by high concentrations of U (up to 7207 μg/g), Se (up to 253 μg/g), Mo (1248 μg/g), and Re (up to 34 μg/g), as well as As (up to 234 μg/g) and Hg (up to 3858 ng/g). Relative to the upper continental crust, the rare earth elements (REEs) in the coals are characterized by heavy or/and medium REE enrichment. The minerals in the Yili coals are mainly quartz, kaolinite, illite and illite/smectite, as well as, to a lesser extent, K-feldspar, chlorite, pyrite, and trace amounts of calcite, dolomite, amphibole, millerite, chalcopyrite, cattierite, siegenite, ferroselite, krutaite, eskebornite, pitchblende, coffinite, silicorhabdophane, and zircon. The enrichment and modes of occurrence of the trace elements, and also of the minerals in the coal, are attributed to derivation from a sediment source region of felsic and intermediate petrological composition, and to two different later-stage solutions (a U–Se–Mo–Re rich infiltrational and a Hg–As-rich exfiltrational volcanogenic solution). The main elements with high enrichment factors, U, Se, As, and Hg, overall exhibit a mixed organic–inorganic affinity. The uranium minerals, pitchblende and coffinite, occur as cavity-fillings in structured inertinite macerals. Selenium, As, and Hg in high-pyrite samples mainly show a sulfide affinity.
-
elements and phosphorus minerals in the middle jurassic inertinite rich coals of the muli coalfield on the tibetan plateau
International Journal of Coal Geology, 2015Co-Authors: Shifeng Dai, Colin R. Ward, James C. Hower, Jennifer M K Okeefe, Wenmu Guo, Hongjian Song, Panpan Xie, Madison M Hood, Xiaoyun YanAbstract:Abstract The content, modes of occurrence, and origin of elements and phosphorus minerals in the Jurassic coals of the Muli Coalfield, on the Tibetan Plateau, were investigated using optical microscopy, field emission-scanning electron microscopy in conjunction with energy-dispersive X-ray spectrometry, X-ray powder diffraction, X-ray fluorescence spectrometry, and inductively coupled plasma mass spectrometry. The Muli coals (L1 and L2 Coals) are of high volatile A Bituminous to medium volatile Bituminous Rank, characterized by low-sulfur contents, and are generally dominated by the inertinite-group macerals (predominantly semifusinite and fusinite). The L1 Coal contains abundant apatite (7.9% on average, on an organic-matter-free basis) and alumino-phosphate minerals of goyazite–gorceixite–crandallite group (4.9% on average), and, accordingly, the concentrations of elements F (253 μg/g on average), P (2349 μg/g), Sr (526 μg/g), and Ba (790 μg/g) are elevated as compared with common world hard coals. The deposition of phosphorous-bearing minerals in the Muli coals was not derived from volcanic input; penetration of Ca- and Al-rich solutions, release of phosphorus from organic matter during plant decay, and an appropriate sedimentary environment (such as low pH, low water table for peat, and oxidizing conditions) were critical factors in deposition of the phosphorus minerals.
-
mineralogical and geochemical compositions of the pennsylvanian coal in the adaohai mine daqingshan coalfield inner mongolia china modes of occurrence and origin of diaspore gorceixite and ammonian illite
International Journal of Coal Geology, 2012Co-Authors: Yaofa Jiang, Colin R. Ward, Xibo Wang, Tian Li, Heming Tian, Dao ZhouAbstract:Abstract Aluminum-hydroxide (boehmite)-rich Pennsylvanian coals of high volatile A Bituminous Rank were found previously in the Jungar Coalfield, Inner Mongolia, China. This paper reports new results on 48 bench samples of the CP2 coal from the adjacent Adaohai Mine, Daqingshan Coalfield, Inner Mongolia, and provides new insights into the origin and modes of occurrence of the minerals and elements present in the CP2 coal. Compared to the same coal in the adjacent mines, the CP2 coal in the Adaohai Mine has a higher Rank (Ro, ran = 1.58%), which is attributed to igneous intrusions during the Late Jurassic and Early Cretaceous Epochs. The proportion of inertinite (35.3%) in the coal is higher than that in other Late Paleozoic coals in northern China but lower than that in the Jungar coals. Minerals in the CP2 coal include diaspore, boehmite, gorceixite, calcite, dolomite, siderite, clay minerals (kaolinite and ammonian illite), and trace amounts of anatase, fluorapatite, quartz, and pyrite. Based on mineral proportions in the coal bench samples, the CP2 coal may be divided into four Zones (I to IV) from bottom to top. The major mineral in Zones I and IV is kaolinite. Zones II and III are mainly composed of ammonian illite, diaspore, boehmite, gorceixite, calcite, dolomite, and siderite. Diaspore-, boehmite-, and gorceixite-forming materials were derived from oxidized bauxite in the weathered crust of the Benxi Formation in the sediment-source region during peat accumulation. However, gorceixite may have formed earlier than diaspore; the diaspore was derived from gibbsite that was subjected to dehydration by the heat of the igneous intrusions. The ammonian illite may have been formed at a relatively high temperature by interaction of kaolinite with nitrogen released from the organic matter in the coal during metamorphism caused by the igneous intrusion. The calcite and dolomite occur as epigenetic cell- and fracture-fillings and were probably derived from the igneous fluids. Compared to the common Chinese and world coals, the CP2 coal is enriched in CaO (1.69%), MgO (0.32%), P2O5 (0.214%), F (207 μg/g), Ga (16.3 μg/g), Zr (446 μg/g), Ba (276 μg/g), Hg (0.33 μg/g), and Th (12.4 μg/g), but has a lower SiO2/Al2O3 ratio due to the higher proportions of diaspore, boehmite, and gorceixite in the coal. The F occurs mainly in gorceixite and fluorapatite. The major carriers of Ga are diaspore and kaolinite but not gorceixite. Barium mainly occurs in gorceixite and barite. Mercury was probably derived from the igneous intrusion and is distributed in both the organic matter and the minerals. The elements are classified into five associations by cluster analysis, Groups A, B, C, D, and E. Group A represents a REE-Be-Y-Se-Ga-Ge-Sc-In-Pb-Bi-Nb-Ta-TiO2-W-Hg-Sb-Zr-Hf-Th-U association. Most of the elements in Group A are lithophile elements that occur in aluminosilicate minerals. Group B (Sn-Te-Zn-Cd-V-As-Cr-Cu-Mo-Ni-Re) is weakly correlated with ash yield and is associated with unidentified trace sulfide minerals. Elements in Group C (Ad-Na2O-Al2O3-SiO2- Li-K2O-Rb-Cs-Tl association) probably occur in the clay minerals and diaspore. Group D consists of P2O5, Ba, F, Sr, S, and Cl, and with the exception of S, they occur in minerals (gorceixite and fluorapatite). Oxides of Fe2O3-MnO-CaO-MgO make up Group E and mainly occur in the carbonate minerals. The coals are enriched in light REEs and the LREEs–HREEs have been highly fractionated, with an average (La/Yb)N of 8.71. The heavy REEs in the coals have a stronger organic affinity than the LREEs.
-
mineralogical and geochemical compositions of the pennsylvanian coal in the adaohai mine daqingshan coalfield inner mongolia china modes of occurrence and origin of diaspore gorceixite and ammonian illite
International Journal of Coal Geology, 2012Co-Authors: Shifeng Dai, Colin R. Ward, Yaofa Jiang, Xibo Wang, Heming Tian, Jianhua Zou, Weifeng Xue, Shande Liu, Xinhao Sun, Dao ZhouAbstract:Abstract Aluminum-hydroxide (boehmite)-rich Pennsylvanian coals of high volatile A Bituminous Rank were found previously in the Jungar Coalfield, Inner Mongolia, China. This paper reports new results on 48 bench samples of the CP2 coal from the adjacent Adaohai Mine, Daqingshan Coalfield, Inner Mongolia, and provides new insights into the origin and modes of occurrence of the minerals and elements present in the CP2 coal. Compared to the same coal in the adjacent mines, the CP2 coal in the Adaohai Mine has a higher Rank (Ro, ran = 1.58%), which is attributed to igneous intrusions during the Late Jurassic and Early Cretaceous Epochs. The proportion of inertinite (35.3%) in the coal is higher than that in other Late Paleozoic coals in northern China but lower than that in the Jungar coals. Minerals in the CP2 coal include diaspore, boehmite, gorceixite, calcite, dolomite, siderite, clay minerals (kaolinite and ammonian illite), and trace amounts of anatase, fluorapatite, quartz, and pyrite. Based on mineral proportions in the coal bench samples, the CP2 coal may be divided into four Zones (I to IV) from bottom to top. The major mineral in Zones I and IV is kaolinite. Zones II and III are mainly composed of ammonian illite, diaspore, boehmite, gorceixite, calcite, dolomite, and siderite. Diaspore-, boehmite-, and gorceixite-forming materials were derived from oxidized bauxite in the weathered crust of the Benxi Formation in the sediment-source region during peat accumulation. However, gorceixite may have formed earlier than diaspore; the diaspore was derived from gibbsite that was subjected to dehydration by the heat of the igneous intrusions. The ammonian illite may have been formed at a relatively high temperature by interaction of kaolinite with nitrogen released from the organic matter in the coal during metamorphism caused by the igneous intrusion. The calcite and dolomite occur as epigenetic cell- and fracture-fillings and were probably derived from the igneous fluids. Compared to the common Chinese and world coals, the CP2 coal is enriched in CaO (1.69%), MgO (0.32%), P2O5 (0.214%), F (207 μg/g), Ga (16.3 μg/g), Zr (446 μg/g), Ba (276 μg/g), Hg (0.33 μg/g), and Th (12.4 μg/g), but has a lower SiO2/Al2O3 ratio due to the higher proportions of diaspore, boehmite, and gorceixite in the coal. The F occurs mainly in gorceixite and fluorapatite. The major carriers of Ga are diaspore and kaolinite but not gorceixite. Barium mainly occurs in gorceixite and barite. Mercury was probably derived from the igneous intrusion and is distributed in both the organic matter and the minerals. The elements are classified into five associations by cluster analysis, Groups A, B, C, D, and E. Group A represents a REE-Be-Y-Se-Ga-Ge-Sc-In-Pb-Bi-Nb-Ta-TiO2-W-Hg-Sb-Zr-Hf-Th-U association. Most of the elements in Group A are lithophile elements that occur in aluminosilicate minerals. Group B (Sn-Te-Zn-Cd-V-As-Cr-Cu-Mo-Ni-Re) is weakly correlated with ash yield and is associated with unidentified trace sulfide minerals. Elements in Group C (Ad-Na2O-Al2O3-SiO2- Li-K2O-Rb-Cs-Tl association) probably occur in the clay minerals and diaspore. Group D consists of P2O5, Ba, F, Sr, S, and Cl, and with the exception of S, they occur in minerals (gorceixite and fluorapatite). Oxides of Fe2O3-MnO-CaO-MgO make up Group E and mainly occur in the carbonate minerals. The coals are enriched in light REEs and the LREEs–HREEs have been highly fractionated, with an average (La/Yb)N of 8.71. The heavy REEs in the coals have a stronger organic affinity than the LREEs.
Shifeng Dai - One of the best experts on this subject based on the ideXlab platform.
-
modes of occurrence and origin of mineral matter in the palaeogene coal no 19 2 from the hunchun coalfield jilin province china
International Journal of Coal Geology, 2018Co-Authors: Shifeng Dai, Colin R. Ward, Wenmu Guo, David French, Victor P Nechaev, Baruch Spiro, Robert B FinkelmanAbstract:Abstract Previous investigations on minerals and elements in coals from northeastern China are very scarce. This paper investigates the mineralogy and geochemistry of the Palaeogene No. 19-2 Coal, parting, and host rocks (roof and floor strata) in the Baliancheng mine, Hunchun Coalfield, Jilin Province, northeastern China. Samples collected from this coalfield were analyzed using low-temperature ashing plus X-ray diffraction analysis, scanning electron microscopy in combination with energy-dispersive X-ray spectrometry, X-ray fluorescence spectrometry, and inductively coupled plasma mass spectrometry. The investigated coal is of subBituminous A to high volatile Bituminous Rank (0.50–0.56% Ro,ran) and has a low sulfur content (0.25% on average). The mineral assemblage of the coal is dominated by kaolinite, illite and expandable clays, and quartz, with a trace of albite. In comparison with low-Rank coals worldwide, the No. 19-2 Coal is enriched in Cs, V, and Mo. The minerals and elements in the coal and its roof and floor strata were mainly derived from the Mesozoic (Jurassic-Lower Cretaceous) intermediate-felsic volcanic rocks surrounding the coal basin. The parting within the coal seam is identified as a tonstein (bed of altered volcanic ash) based on its mineral composition, dominantly of vermicular and book-like kaolinite (plus smectite, high-temperature quartz, sanidine, apatite, and ilmenite), and its persistent distribution throughout the coal deposit. Based on these features and its chemical composition, this tonstein is deduced to have been derived from a Paleogene intermediate-felsic volcanic ash, which is characterized by some adakitic signatures of trace elements, and terrigenous materials. Normalized to the upper continental crust, the investigated samples (particularly the tonstein layer) show positive Eu anomalies inherited from the source rocks. This is in contrast to the coals, host rocks, and tonsteins with intermediate-felsic compositions in many other coal deposits, which are generally characterized by negative Eu anomalies. Geochemical and mineralogical features also indicate that the sedimentary materials of the tonstein, and, to a lesser extent, the floor horizon, were of aeolian origin, but those of most coal plies and roof strata were the result of aqueous deposition.
-
geochemical and mineralogical evidence for a coal hosted uranium deposit in the yili basin xinjiang northwestern china
Ore Geology Reviews, 2015Co-Authors: Shifeng Dai, Colin R. Ward, James C. Hower, Jianye Yang, Huidong Liu, Trent M Garrison, David French, Jennifer M K OkeefeAbstract:Abstract The petrological, geochemical, and mineralogical compositions of the coal-hosted Jurassic uranium ore deposit in the Yili Basin of Xinjiang province, northwestern China, were investigated using optical microscopy and field emission-scanning electron microscopy in conjunction with an energy-dispersive X-ray spectrometer, as well as X-ray powder diffraction, X-ray fluorescence, and inductively coupled plasma mass spectrometry. The Yili coal is of high volatile C/B Bituminous Rank (0.51–0.59% vitrinite reflectance) and has a medium sulfur content (1.32% on average). Fusinite and semifusinite generally dominate the maceral assemblage, which exhibits forms suggesting fire-driven formation of those macerals together with forms suggesting degradation of wood followed by burning. The Yili coals are characterized by high concentrations of U (up to 7207 μg/g), Se (up to 253 μg/g), Mo (1248 μg/g), and Re (up to 34 μg/g), as well as As (up to 234 μg/g) and Hg (up to 3858 ng/g). Relative to the upper continental crust, the rare earth elements (REEs) in the coals are characterized by heavy or/and medium REE enrichment. The minerals in the Yili coals are mainly quartz, kaolinite, illite and illite/smectite, as well as, to a lesser extent, K-feldspar, chlorite, pyrite, and trace amounts of calcite, dolomite, amphibole, millerite, chalcopyrite, cattierite, siegenite, ferroselite, krutaite, eskebornite, pitchblende, coffinite, silicorhabdophane, and zircon. The enrichment and modes of occurrence of the trace elements, and also of the minerals in the coal, are attributed to derivation from a sediment source region of felsic and intermediate petrological composition, and to two different later-stage solutions (a U–Se–Mo–Re rich infiltrational and a Hg–As-rich exfiltrational volcanogenic solution). The main elements with high enrichment factors, U, Se, As, and Hg, overall exhibit a mixed organic–inorganic affinity. The uranium minerals, pitchblende and coffinite, occur as cavity-fillings in structured inertinite macerals. Selenium, As, and Hg in high-pyrite samples mainly show a sulfide affinity.
-
elements and phosphorus minerals in the middle jurassic inertinite rich coals of the muli coalfield on the tibetan plateau
International Journal of Coal Geology, 2015Co-Authors: Shifeng Dai, Colin R. Ward, James C. Hower, Jennifer M K Okeefe, Wenmu Guo, Hongjian Song, Panpan Xie, Madison M Hood, Xiaoyun YanAbstract:Abstract The content, modes of occurrence, and origin of elements and phosphorus minerals in the Jurassic coals of the Muli Coalfield, on the Tibetan Plateau, were investigated using optical microscopy, field emission-scanning electron microscopy in conjunction with energy-dispersive X-ray spectrometry, X-ray powder diffraction, X-ray fluorescence spectrometry, and inductively coupled plasma mass spectrometry. The Muli coals (L1 and L2 Coals) are of high volatile A Bituminous to medium volatile Bituminous Rank, characterized by low-sulfur contents, and are generally dominated by the inertinite-group macerals (predominantly semifusinite and fusinite). The L1 Coal contains abundant apatite (7.9% on average, on an organic-matter-free basis) and alumino-phosphate minerals of goyazite–gorceixite–crandallite group (4.9% on average), and, accordingly, the concentrations of elements F (253 μg/g on average), P (2349 μg/g), Sr (526 μg/g), and Ba (790 μg/g) are elevated as compared with common world hard coals. The deposition of phosphorous-bearing minerals in the Muli coals was not derived from volcanic input; penetration of Ca- and Al-rich solutions, release of phosphorus from organic matter during plant decay, and an appropriate sedimentary environment (such as low pH, low water table for peat, and oxidizing conditions) were critical factors in deposition of the phosphorus minerals.
-
mineralogical and geochemical compositions of the pennsylvanian coal in the adaohai mine daqingshan coalfield inner mongolia china modes of occurrence and origin of diaspore gorceixite and ammonian illite
International Journal of Coal Geology, 2012Co-Authors: Shifeng Dai, Colin R. Ward, Yaofa Jiang, Xibo Wang, Heming Tian, Jianhua Zou, Weifeng Xue, Shande Liu, Xinhao Sun, Dao ZhouAbstract:Abstract Aluminum-hydroxide (boehmite)-rich Pennsylvanian coals of high volatile A Bituminous Rank were found previously in the Jungar Coalfield, Inner Mongolia, China. This paper reports new results on 48 bench samples of the CP2 coal from the adjacent Adaohai Mine, Daqingshan Coalfield, Inner Mongolia, and provides new insights into the origin and modes of occurrence of the minerals and elements present in the CP2 coal. Compared to the same coal in the adjacent mines, the CP2 coal in the Adaohai Mine has a higher Rank (Ro, ran = 1.58%), which is attributed to igneous intrusions during the Late Jurassic and Early Cretaceous Epochs. The proportion of inertinite (35.3%) in the coal is higher than that in other Late Paleozoic coals in northern China but lower than that in the Jungar coals. Minerals in the CP2 coal include diaspore, boehmite, gorceixite, calcite, dolomite, siderite, clay minerals (kaolinite and ammonian illite), and trace amounts of anatase, fluorapatite, quartz, and pyrite. Based on mineral proportions in the coal bench samples, the CP2 coal may be divided into four Zones (I to IV) from bottom to top. The major mineral in Zones I and IV is kaolinite. Zones II and III are mainly composed of ammonian illite, diaspore, boehmite, gorceixite, calcite, dolomite, and siderite. Diaspore-, boehmite-, and gorceixite-forming materials were derived from oxidized bauxite in the weathered crust of the Benxi Formation in the sediment-source region during peat accumulation. However, gorceixite may have formed earlier than diaspore; the diaspore was derived from gibbsite that was subjected to dehydration by the heat of the igneous intrusions. The ammonian illite may have been formed at a relatively high temperature by interaction of kaolinite with nitrogen released from the organic matter in the coal during metamorphism caused by the igneous intrusion. The calcite and dolomite occur as epigenetic cell- and fracture-fillings and were probably derived from the igneous fluids. Compared to the common Chinese and world coals, the CP2 coal is enriched in CaO (1.69%), MgO (0.32%), P2O5 (0.214%), F (207 μg/g), Ga (16.3 μg/g), Zr (446 μg/g), Ba (276 μg/g), Hg (0.33 μg/g), and Th (12.4 μg/g), but has a lower SiO2/Al2O3 ratio due to the higher proportions of diaspore, boehmite, and gorceixite in the coal. The F occurs mainly in gorceixite and fluorapatite. The major carriers of Ga are diaspore and kaolinite but not gorceixite. Barium mainly occurs in gorceixite and barite. Mercury was probably derived from the igneous intrusion and is distributed in both the organic matter and the minerals. The elements are classified into five associations by cluster analysis, Groups A, B, C, D, and E. Group A represents a REE-Be-Y-Se-Ga-Ge-Sc-In-Pb-Bi-Nb-Ta-TiO2-W-Hg-Sb-Zr-Hf-Th-U association. Most of the elements in Group A are lithophile elements that occur in aluminosilicate minerals. Group B (Sn-Te-Zn-Cd-V-As-Cr-Cu-Mo-Ni-Re) is weakly correlated with ash yield and is associated with unidentified trace sulfide minerals. Elements in Group C (Ad-Na2O-Al2O3-SiO2- Li-K2O-Rb-Cs-Tl association) probably occur in the clay minerals and diaspore. Group D consists of P2O5, Ba, F, Sr, S, and Cl, and with the exception of S, they occur in minerals (gorceixite and fluorapatite). Oxides of Fe2O3-MnO-CaO-MgO make up Group E and mainly occur in the carbonate minerals. The coals are enriched in light REEs and the LREEs–HREEs have been highly fractionated, with an average (La/Yb)N of 8.71. The heavy REEs in the coals have a stronger organic affinity than the LREEs.
Dao Zhou - One of the best experts on this subject based on the ideXlab platform.
-
mineralogical and geochemical compositions of the pennsylvanian coal in the adaohai mine daqingshan coalfield inner mongolia china modes of occurrence and origin of diaspore gorceixite and ammonian illite
International Journal of Coal Geology, 2012Co-Authors: Yaofa Jiang, Colin R. Ward, Xibo Wang, Tian Li, Heming Tian, Dao ZhouAbstract:Abstract Aluminum-hydroxide (boehmite)-rich Pennsylvanian coals of high volatile A Bituminous Rank were found previously in the Jungar Coalfield, Inner Mongolia, China. This paper reports new results on 48 bench samples of the CP2 coal from the adjacent Adaohai Mine, Daqingshan Coalfield, Inner Mongolia, and provides new insights into the origin and modes of occurrence of the minerals and elements present in the CP2 coal. Compared to the same coal in the adjacent mines, the CP2 coal in the Adaohai Mine has a higher Rank (Ro, ran = 1.58%), which is attributed to igneous intrusions during the Late Jurassic and Early Cretaceous Epochs. The proportion of inertinite (35.3%) in the coal is higher than that in other Late Paleozoic coals in northern China but lower than that in the Jungar coals. Minerals in the CP2 coal include diaspore, boehmite, gorceixite, calcite, dolomite, siderite, clay minerals (kaolinite and ammonian illite), and trace amounts of anatase, fluorapatite, quartz, and pyrite. Based on mineral proportions in the coal bench samples, the CP2 coal may be divided into four Zones (I to IV) from bottom to top. The major mineral in Zones I and IV is kaolinite. Zones II and III are mainly composed of ammonian illite, diaspore, boehmite, gorceixite, calcite, dolomite, and siderite. Diaspore-, boehmite-, and gorceixite-forming materials were derived from oxidized bauxite in the weathered crust of the Benxi Formation in the sediment-source region during peat accumulation. However, gorceixite may have formed earlier than diaspore; the diaspore was derived from gibbsite that was subjected to dehydration by the heat of the igneous intrusions. The ammonian illite may have been formed at a relatively high temperature by interaction of kaolinite with nitrogen released from the organic matter in the coal during metamorphism caused by the igneous intrusion. The calcite and dolomite occur as epigenetic cell- and fracture-fillings and were probably derived from the igneous fluids. Compared to the common Chinese and world coals, the CP2 coal is enriched in CaO (1.69%), MgO (0.32%), P2O5 (0.214%), F (207 μg/g), Ga (16.3 μg/g), Zr (446 μg/g), Ba (276 μg/g), Hg (0.33 μg/g), and Th (12.4 μg/g), but has a lower SiO2/Al2O3 ratio due to the higher proportions of diaspore, boehmite, and gorceixite in the coal. The F occurs mainly in gorceixite and fluorapatite. The major carriers of Ga are diaspore and kaolinite but not gorceixite. Barium mainly occurs in gorceixite and barite. Mercury was probably derived from the igneous intrusion and is distributed in both the organic matter and the minerals. The elements are classified into five associations by cluster analysis, Groups A, B, C, D, and E. Group A represents a REE-Be-Y-Se-Ga-Ge-Sc-In-Pb-Bi-Nb-Ta-TiO2-W-Hg-Sb-Zr-Hf-Th-U association. Most of the elements in Group A are lithophile elements that occur in aluminosilicate minerals. Group B (Sn-Te-Zn-Cd-V-As-Cr-Cu-Mo-Ni-Re) is weakly correlated with ash yield and is associated with unidentified trace sulfide minerals. Elements in Group C (Ad-Na2O-Al2O3-SiO2- Li-K2O-Rb-Cs-Tl association) probably occur in the clay minerals and diaspore. Group D consists of P2O5, Ba, F, Sr, S, and Cl, and with the exception of S, they occur in minerals (gorceixite and fluorapatite). Oxides of Fe2O3-MnO-CaO-MgO make up Group E and mainly occur in the carbonate minerals. The coals are enriched in light REEs and the LREEs–HREEs have been highly fractionated, with an average (La/Yb)N of 8.71. The heavy REEs in the coals have a stronger organic affinity than the LREEs.
-
mineralogical and geochemical compositions of the pennsylvanian coal in the adaohai mine daqingshan coalfield inner mongolia china modes of occurrence and origin of diaspore gorceixite and ammonian illite
International Journal of Coal Geology, 2012Co-Authors: Shifeng Dai, Colin R. Ward, Yaofa Jiang, Xibo Wang, Heming Tian, Jianhua Zou, Weifeng Xue, Shande Liu, Xinhao Sun, Dao ZhouAbstract:Abstract Aluminum-hydroxide (boehmite)-rich Pennsylvanian coals of high volatile A Bituminous Rank were found previously in the Jungar Coalfield, Inner Mongolia, China. This paper reports new results on 48 bench samples of the CP2 coal from the adjacent Adaohai Mine, Daqingshan Coalfield, Inner Mongolia, and provides new insights into the origin and modes of occurrence of the minerals and elements present in the CP2 coal. Compared to the same coal in the adjacent mines, the CP2 coal in the Adaohai Mine has a higher Rank (Ro, ran = 1.58%), which is attributed to igneous intrusions during the Late Jurassic and Early Cretaceous Epochs. The proportion of inertinite (35.3%) in the coal is higher than that in other Late Paleozoic coals in northern China but lower than that in the Jungar coals. Minerals in the CP2 coal include diaspore, boehmite, gorceixite, calcite, dolomite, siderite, clay minerals (kaolinite and ammonian illite), and trace amounts of anatase, fluorapatite, quartz, and pyrite. Based on mineral proportions in the coal bench samples, the CP2 coal may be divided into four Zones (I to IV) from bottom to top. The major mineral in Zones I and IV is kaolinite. Zones II and III are mainly composed of ammonian illite, diaspore, boehmite, gorceixite, calcite, dolomite, and siderite. Diaspore-, boehmite-, and gorceixite-forming materials were derived from oxidized bauxite in the weathered crust of the Benxi Formation in the sediment-source region during peat accumulation. However, gorceixite may have formed earlier than diaspore; the diaspore was derived from gibbsite that was subjected to dehydration by the heat of the igneous intrusions. The ammonian illite may have been formed at a relatively high temperature by interaction of kaolinite with nitrogen released from the organic matter in the coal during metamorphism caused by the igneous intrusion. The calcite and dolomite occur as epigenetic cell- and fracture-fillings and were probably derived from the igneous fluids. Compared to the common Chinese and world coals, the CP2 coal is enriched in CaO (1.69%), MgO (0.32%), P2O5 (0.214%), F (207 μg/g), Ga (16.3 μg/g), Zr (446 μg/g), Ba (276 μg/g), Hg (0.33 μg/g), and Th (12.4 μg/g), but has a lower SiO2/Al2O3 ratio due to the higher proportions of diaspore, boehmite, and gorceixite in the coal. The F occurs mainly in gorceixite and fluorapatite. The major carriers of Ga are diaspore and kaolinite but not gorceixite. Barium mainly occurs in gorceixite and barite. Mercury was probably derived from the igneous intrusion and is distributed in both the organic matter and the minerals. The elements are classified into five associations by cluster analysis, Groups A, B, C, D, and E. Group A represents a REE-Be-Y-Se-Ga-Ge-Sc-In-Pb-Bi-Nb-Ta-TiO2-W-Hg-Sb-Zr-Hf-Th-U association. Most of the elements in Group A are lithophile elements that occur in aluminosilicate minerals. Group B (Sn-Te-Zn-Cd-V-As-Cr-Cu-Mo-Ni-Re) is weakly correlated with ash yield and is associated with unidentified trace sulfide minerals. Elements in Group C (Ad-Na2O-Al2O3-SiO2- Li-K2O-Rb-Cs-Tl association) probably occur in the clay minerals and diaspore. Group D consists of P2O5, Ba, F, Sr, S, and Cl, and with the exception of S, they occur in minerals (gorceixite and fluorapatite). Oxides of Fe2O3-MnO-CaO-MgO make up Group E and mainly occur in the carbonate minerals. The coals are enriched in light REEs and the LREEs–HREEs have been highly fractionated, with an average (La/Yb)N of 8.71. The heavy REEs in the coals have a stronger organic affinity than the LREEs.
Daigoro Hayashi - One of the best experts on this subject based on the ideXlab platform.
-
geology and coal bed methane resource potential of the gondwana barapukuria coal basin dinajpur bangladesh
International Journal of Coal Geology, 2008Co-Authors: Md Rafiqul Islam, Daigoro HayashiAbstract:Abstract With an area of 5.16 km2, the Barapukuria coal deposit is one of the five largest Gondwana coal basins in Bangladesh, and is located in the north west of the country close to the towns of Dinajpur and Saidpur. The existence of the basin was initially indicated by a negative gravity anomaly in oil and gas exploration. Exploration for the deposit was commenced by the Geological Survey of Bangladesh (GSB), with seven surface boreholes that confirmed the existence of a significant coal deposit. The deposit occurs as an asymmetrical synclinal structure with an axis striking approximately N-S. The deposit is limited to the east by a large normal fault which has displaced Archaean metamorphics against the Gondwana sediments. The coal-bearing sediments are comprised of Gondwana Permian-age sandstones, siltstones, subordinate carbonaceous shales, and six correlated coal seams. The Gondwana sediments are unconformably overlain by Tertiary and Quaternary deposits, against which the coal seams are successively subcropped to the west. Within the structural limits of the basin, approximately 377 Mt coal in-situ has been quantified in the six coal seams that range in depth from 118 to 518 m below surface. Due to the synclinal nature of the deposit, the upper coal seams, designated I to V, occur over diminishing areal extent with decreasing depth. The principal seam of interest is the lowermost Seam VI, with a variable thickness across the deposit from 22 m in the northern part of the deposit to more than 42 m in the southern and eastern areas. Development of the Barapukuria Mine, the country's first coal mine, commenced in 1996 with the construction of two vertical shafts. Coal production from Seam VI began in 2005 and continues at the present time. Seam VI coal is high volatile B Bituminous Rank. About 34 Mt of coal has been estimated as recoverable resources, utilising descensional multi-slice longwall mining. The mine design and development have been severely constrained by adverse seam gradients and the presence of the overlying water-bearing Tertiary Dupi Tila sediments. The potential of coal bed methane extraction has been investigated as an alternative to underground mining. The study considers the Barapukuria deposit in terms of its geological structure, geothermal gradient, and the Rank, porosity and permeability of the coal seams as determined by several phases of exploration of the area. The methane content of the Bituminous coal at Barapukuria varies within the range 6.51–12.68 m3/t, representing a potential resource of more than 5 Gm3 of gas.
-
geology and coal bed methane resource potential of the gondwana barapukuria coal basin dinajpur bangladesh
International Journal of Coal Geology, 2008Co-Authors: Md Rafiqul Islam, Daigoro HayashiAbstract:Abstract With an area of 5.16 km2, the Barapukuria coal deposit is one of the five largest Gondwana coal basins in Bangladesh, and is located in the north west of the country close to the towns of Dinajpur and Saidpur. The existence of the basin was initially indicated by a negative gravity anomaly in oil and gas exploration. Exploration for the deposit was commenced by the Geological Survey of Bangladesh (GSB), with seven surface boreholes that confirmed the existence of a significant coal deposit. The deposit occurs as an asymmetrical synclinal structure with an axis striking approximately N-S. The deposit is limited to the east by a large normal fault which has displaced Archaean metamorphics against the Gondwana sediments. The coal-bearing sediments are comprised of Gondwana Permian-age sandstones, siltstones, subordinate carbonaceous shales, and six correlated coal seams. The Gondwana sediments are unconformably overlain by Tertiary and Quaternary deposits, against which the coal seams are successively subcropped to the west. Within the structural limits of the basin, approximately 377 Mt coal in-situ has been quantified in the six coal seams that range in depth from 118 to 518 m below surface. Due to the synclinal nature of the deposit, the upper coal seams, designated I to V, occur over diminishing areal extent with decreasing depth. The principal seam of interest is the lowermost Seam VI, with a variable thickness across the deposit from 22 m in the northern part of the deposit to more than 42 m in the southern and eastern areas. Development of the Barapukuria Mine, the country's first coal mine, commenced in 1996 with the construction of two vertical shafts. Coal production from Seam VI began in 2005 and continues at the present time. Seam VI coal is high volatile B Bituminous Rank. About 34 Mt of coal has been estimated as recoverable resources, utilising descensional multi-slice longwall mining. The mine design and development have been severely constrained by adverse seam gradients and the presence of the overlying water-bearing Tertiary Dupi Tila sediments. The potential of coal bed methane extraction has been investigated as an alternative to underground mining. The study considers the Barapukuria deposit in terms of its geological structure, geothermal gradient, and the Rank, porosity and permeability of the coal seams as determined by several phases of exploration of the area. The methane content of the Bituminous coal at Barapukuria varies within the range 6.51–12.68 m3/t, representing a potential resource of more than 5 Gm3 of gas.