geochemical and mineralogical evidence for a coal hosted uranium deposit in the yili basin xinjiang northwestern china 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 g g se up to 253 g g mo 1248 g g and re up to 34 g g as well as as up to 234 g 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

evidence for multiple sources for inorganic components in the tucheng coal deposit western guizhou china and the lack of critical elements abstract terrigenous materials from sediment source regions are important controls on the types and concentrations of inorganic components in coal the kangdian upland dominated by the emeishan basalts is the dominant terrigenous supplier for most of the late permian coals as well as for their associated host rocks roof and floor strata in southwestern china the high volatile bituminous coals nos 3 and 6 coals are the two major minable coal seams in the tucheng coal deposit in southwestern china unlike most late permian coals in this region that are characterized by elevated concentrations of the element assemblage sc v cr co ni cu zn se these two coals are not enriched in this assemblage although se is slightly concentrated the mineralogical e g relatively abundant quartz and mixed layer illite smectite and elemental distribution patterns e g spider diagrams of rare earth elements discrimination diagrams of al2o3 tio2 and zr tio2 nb y and elemental assemblages indicate that the inorganic components in the two coal seams were mainly derived from unidentified volcanic arc and or distal orogens while the clastic components in the roof and floor strata of the two coal seams were mainly supplied by the high ti emeishan basalts the two partings in the two coal seams identified as tonsteins were probably derived from the final rejuvenated activity of the emeishan plume critical elements in the two coals and associated non coal horizons partings roof and floor strata are economically unpromising indicating that prospecting for late permian coal hosted critical metal ore deposits in the vicinity of the emeishan plume in southwestern china should not be focused on coals with inorganic components derived mostly from distal volcanic arcs and orogens and high ti emeishan basalts and a minor contribution of volcanic ashes resulting from the final rejuvenated activity of the emeishan plume

modes of occurrence and origin of mineral matter in the palaeogene coal no 19 2 from the hunchun coalfield jilin province china 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

element mobility from fresh and long stored acidic fly ashes associated with an australian power station abstract the mobility of major and trace elements in a series of ashes from pulverised coal combustion stored in dams and similar repositories for up to 25 years has been investigated comparison with the mobility of the same elements from equivalent fresh dry ash material has been used to provide a basis for assessing the long term changes in element mobility during ash storage laboratory testing at different initial ph values indicates an increase in the natural acidic ph and a decrease in the buffering capacity of the ash by contact with water during handling and storage suggesting loss of components such as so 4 from the surfaces of the ash particles with even relatively brief water contact most elements show lesser degrees of mobility from ashes that have been stored under water even if only for a relatively short period than from the fresh dry material there are however some exceptions such as mo which appear to have increased mobility from the longer stored ashes due to a progressive rise in ph levels relatively little difference is noted between the mobility of most elements in the water stored ashes regardless of whether they were only recently emplaced or have been in the dam for 20 years or more this suggests that equilibrium has been established between the ash and the pore water and that once the readily leached fraction had been removed the ash water system remained relatively stable with time ash that had been deposited under water in a trial ash pond and then drained and exposed to dry storage conditions for many years however showed many similar leaching characteristics to the fresh dry ash material this suggests that at least some elements or ions e g so 4 2 may be re adsorbed on to the ash particles with exposure after drying or that additional elements of similar characteristics may be released allowing a new set of equilibrium conditions to be established the concentrations of most elements in the laboratory test leachates are of a similar order of magnitude to the concentrations of the same elements in the water in the present day ash pond this increases confidence in the use of laboratory tests to provide guidance on the expected behaviour of ash when exposed to water in actual field situations

factors controlling geochemical and mineralogical compositions of coals preserved within marine carbonate successions a case study from the heshan coalfield southern china abstract the late permian coals in the heshan coalfield of southern china are preserved within marine carbonate successions and characterized by super high organic sulfur 5 13 10 82 minerals identified in the coals include quartz kaolinite illite mixed layer illite smectite albite pyrite marcasite calcite and dolomite along with trace amounts of smectite fluorite strontianite rey bearing carbonate minerals jarosite and water bearing fe oxysulfate the coals are very rich in trace elements including f up to 3362 g g v up to 270 g g se up to 24 4 g g mo up to 142 g g u up to 111 g g and to a lesser extent sr y zr nb cd cs heavy rare earth elements hf ta w hg and th previous studies attributed the high organic sulfur and elevated trace elements to the seawater influence or the formation of soil horizons before the accumulation of peat in the basin however mineralogical and geochemical data presented in this study have shown that the sediment source region and multi stage hydrothermal fluids are the dominant influences on the mineralogical composition and elevated trace elements in the coal although seawater influence also contributed to the composition of the mineral matter for example a large proportion of the quartz and clay minerals as well as almost all the albite in both the coal benches and the parting mudstones were derived from detrital materials of terrigenous origin in the yunkai upland high concentrations of lithophile trace elements were also derived from the sediment source region minerals including fluorite calcite dolomite strontianite and rey bearing carbonate minerals were derived from multi stage hydrothermal activities high concentrations of v mo and u that occur through the coal seam sections were probably derived from hydrothermal solutions during peat accumulation or at the early diagenetic stages the hydrothermal fluids also corroded the syngenetically formed minerals quartz albite and pyrite and caused re distribution of lithophile elements from partings to the underlying coal benches resulting in higher key element ratios yb la nb ta and zr hf and more abundant heavy rare earth elements in the coal benches than in the immediately overlying partings

origin of minerals and elements in the late permian coals tonsteins and host rocks of the xinde mine xuanwei eastern yunnan china abstract this paper reports the mineralogical and geochemical compositions of the late permian c2 and c3 coals both medium volatile bituminous coal from the xinde mine near xuanwei in eastern yunnan which is located close to the area with the highest female lung cancer mortality in china the two coals are characterized by high ash yields and low sulfur contents three factors including sediment source region multi stage volcanic ash generation and multi stage hydrothermal fluid injections were responsible for variations in the geochemical and mineralogical compositions of the xinde coals trace elements including v sc co ni cu zn se zr nb hf and ta are enriched in the coals and were mainly derived from the sediment source kangdian upland region major minerals in the samples of coal roof floor and non coal sediment partings include quartz kaolinite and chamosite as well as interstratified illite smectite and anatase chamosite in the coal was derived from reactions between kaolinite and fe mg rich hydrothermal fluids however chamosite in the roof strata was directly precipitated from fe mg rich hydrothermal fluids or was derived from the alteration of precursor minerals e g biotite by hydrothermal fluids quartz in some samples is very high especially in the roof strata of the c2 and c3 coal such high quartz along with minor minerals including pyrite chalcopyrite sphalerite calcite celestite vanadinite barite clausthalite and silicorhabdophane were derived from multi stage hydrothermal fluids the floors of both the c2 and c3 coal seams are fully argillized fine grained tuffaceous claystone and the immediate roof of the c2 coal is argillized coarse grained tuff the original materials of the floors and roofs of these coal seams were high ti alkali basaltic volcanic ashes as indicated by high tio 2 nb and siderophile elements and the distribution patterns of rare earth elements two intra seam tonstein layers in the c3 coal were identified based on their lateral persistence mineralogical mode of occurrence and composition as well as their elemental composition the tonsteins are dominated by kaolinite with minor quartz and possibly mixed layer illite smectite both tonsteins were derived from dacitic magma the ratios of nb ta zr hf and u th are much lower in tonsteins than in the adjacent coal benches which is attributed to the hydrothermal leaching

a novel method to estimate mineral compositions of mudrocks a case study for the canadian unconventional petroleum systems abstract the mineral composition of mudrocks is an essential attribute in controlling the reservoir quality of unconventional petroleum systems the present study introduces a semi quantitative method to estimate mineral phases of mudrocks in various canadian unconventional hydrocarbon systems using total elemental analysis inductively coupled plasma mass spectrometry icp ms and rock eval data total organic carbon toc and mineral carbon minc this method involves statistical analysis based on a sound knowledge of hydrocarbon source rock inorganic geochemistry the workflow can be divided into four steps i converting major elements si al fe k na ca mg ti and p to their oxides ii inferring modes of occurrence of elements using statistical analysis of geochemical data major elements toc and minc iii identifying the mineral types oxide aluminosilicates carbonates sulfide and phosphate according to elemental occurrences and calculating mineral phase concentrations and iv verifying the results by comparing to xrd data on selected samples the results especially for brittle minerals such as quartz carbonates e g calcite dolomite and ankerite and pyrite show that the estimated mineral compositions correspond closely and consistently with measured mineralogy obtained from xrd this method takes advantage of bulk geochemical data already available for hydrocarbon potential and chemostratigraphic studies without devoting additional samples and cost for xrd analysis

geochemistry of source rock controlled late triassic coal an example from the dabaoding coal mine in panzhihua sichuan province southwestern china abstract the geochemistry of source rock controlled coals from the late triassic daqiaodi formation in the dabaoding coal mine of the southwestern sichuan province was investigated a total of 15 coal samples 6 parting samples and 4 roof and floor rock samples from the d15 3 and d18 coals were subjected to proximate and ultimate analyses for coal quality by using lta xrd with siroquant software for minerals xrf for major element oxides icp ms for trace elements icp cct ms for as and se ise for f and a dma 80 analyzer for hg results indicate that the dabaoding d15 3 and d18 coals are classified as low ash and low volatile bituminous coal minerals in coals are dominated by quartz kaolinite illite and dolomite most trace elements in the dabaoding coals are depleted or at normal levels relative to chinese coals or world hard coals except for cr with slight enrichment the dabaoding coals and host rocks are characterized by weakly positive ce and y anomalies strongly positive gd anomalies and weakly negative eu anomalies based on paleogeographical mineralogical and geochemical evidence the sediment source rocks of the daqiaodi coal bearing strata are identified as the panzhihua trachyte at the top of the kangdian upland which exerted crucial impacts on the dabaoding coals

elemental geochemistry and mineralogy of coals and associated coal mine overburden from makum coalfield northeast india the insufficient research on the nature and mode of occurrence of minerals and other inorganic elements of the northeast indian coal deposits has resulted in lack of proper utilization assessment and mitigation of environmental degradation the mineralogical and geochemical aspects of these coals were studied through the techniques such as optical microscopy low temperature quantitative x ray diffraction lta xrd scanning electron microscopy energy dispersive spectroscopy sem eds inductively coupled mass spectroscopy icp ms and chemical analysis techniques the leaching behavior of the elements including rees in presence of water was studied the high organic sulfur 75 of total sulfur and low ash yields were observed in these coals varying with seam depth the dominance of vitrinite 94 1 94 3 with an r max 0 72 0 78 in these coals along with their dominance within the lean organic fraction in the coal mine overburden ob samples was reported the major oxides present in these coals and their associated overburden samples were studied through xrf analysis various mineral phases were identified in both coal and ob samples such as dawsonite pyrite diaspore marcasite gypsum thenardite berzeliite garnet etc the sem eds analysis indicated the presence of siderite pyrite and kaolinite quartz illite etc in the coal ob and leached samples the distribution of concentrations of the 48 trace and rare earth elements rees varying with seam depth were normalized by upper continental crust ucc and found to be lower in comparison to global chinese and usa coals the statistical analysis on the trace and rare earth elements in the coals was performed to know their mutual correlations

mineral composition and geochemical characteristics of the li ga rich coals in the buertaohai tianjiashipan mining district jungar coalfield inner mongolia abstract the coals from the jungar coalfield inner mongolia china have been found to be enriched in ga and li these are valuable metals that are potentially recoverable from coals and or coal combustion residues based on fifteen roof floor parting samples collected from one borehole and one hundred and forty one bulk coal samples collected from three boreholes in the buertaohai tianjiashipan coal mining district jungar coalfield this paper reports new data on the mineral compositions and geochemical characteristics of the jungar li ga rich coals and provides new evidence for the origin and mode of occurrence of al ga and li in these coals the main mineral phases occurring in the coals are kaolinite boehmite calcite with small proportions of quartz pyrite ankerite siderite and trace amounts of microcline and rectorite an unusual mineral phase svanbergite sral 3 po 4 so 4 oh 6 also occurs as a main mineral constituent in the studied coals the mineral phases in the roof floor parting samples are dominantly kaolinite with a small proportion of quartz kaolinite is of both terrigenous and authigenic origin which were possibly derived from terrigenous yinshan oldland sediment source region and or from recrystallization during the coal formation process boehmite and svanbergite are primarily of authigenic origin and were dominantly derived from the weathered bauxite sediment source region calcite may have formed by dissolution of limestone layers close to the margin of coal basin and subsequent deposition of the ca or mg rich carbonates in the cells fractures of the coal seams sulfide minerals in fractures may have been precipitated from epithermal fluids rectorite was probably formed by the reaction of kaolinite with epigenetic low temperature hydrothermal fluids during diagenesis compared to common chinese and worldwide coals the studied jungar coals are much more enriched in al 4 4 6 1 li 70 79 mg kg and ga 14 19 mg kg titanium p sr zr nb th ta hf and rare earth elements rees are also enriched in the studied coals to some extent aluminum in the coals mainly occurs in the form of kaolinite and boehmite whereas lithium may be associated with aluminosilicate minerals kaolinite and illite if present as well as svanbergite gallium principally occurs in kaolinite and to a lesser extent svanbergite strontium p and lrees la ce and rr nd and sm mainly present in svanbergite the source of li and ga in jungar coals is most likely from the yinshan oldland region but there is also a possibility of migration from bauxite of the benxi formation

the occurrence of buddingtonite in super high organic sulphur coals from the yishan coalfield guangxi southern china abstract this paper discusses the identification abundance modes of occurrence and origin of buddingtonite and associated minerals in three lopingian coals from the yishan coalfield guangxi province southern china the coals of this coalfield are preserved within carbonate successions and are characterized by super high organic sulphur contents mostly 6 9 three different types of feldspars have been identified in these coals buddingtonite albite and minor k feldspar both the albite and k feldspar in the coal were largely derived from detrital materials of terrigenous origin although some were authigenically deposited they were subsequently subjected to corrosion dissolution by percolating fluids buddingtonite was derived largely from k feldspar via diffusion mechanisms through the substitution of k by nh4 the latter coming from decomposition of organic matter in the coal or from changes in the organic matter with rank advance a small proportion of the buddingtonite was also derived from albite through the replacement of na by nh4

enrichment of u se mo re v in coals preserved within marine carbonate successions geochemical and mineralogical data from the late permian guiding coalfield guizhou china we present multi element data on the super high organic sulfur shos 5 19 on average coals of late permian age from guiding in guizhou province china the coals formed on restricted carbonate platforms are all highly enriched in s u se mo re v and cr and to a lesser extent ni and cd although the guiding coals were subjected to seawater influence boron is very low and mainly occurs in tourmaline and mixed layer illite smectite uranium mo and v in the coal are mainly associated with the organic matter in addition a small proportion of the u occurs in coffinite and brannerite the major carrier of se is pyrite rather than marcasite rhenium probably occurs in secondary sulfate and carbonate minerals the u bearing coal deposits have the following characteristics the formation age is limited to late permian concentrations of sulfur and rare metals u se mo re v and in some cases rare earth elements and y are highly elevated the u bearing coal beds are intercalated with marine carbonate rocks organic sulfur and rare metals are uniformly distributed within the coal seams and the combustion products e g fly and bottom ash derived from the coal deposits may have potential economic significance for rare metals u se mo re v rare earth elements and y

revisiting the late permian coal from the huayingshan sichuan southwestern china enrichment and occurrence modes of minerals and trace elements abstract the late permian coals from the huayingshan coalfield of southwestern china are significantly enriched in zr 695 g g nb 75 9 g g se 6 99 g g hf 10 1 g g and rare earth elements and y 1423 g g previous studies showed that the sediment source region for these coals was the kangdian upland which was formed at an early stage of the late permian period the source rocks have a basalt composition and those studies attributed the enrichment of the above high field strength elements hfses to derivation from the kangdian upland geochemical and mineralogical data presented in this study show that the dominant sediment source regions for the coal and roof strata of the huayingshan coalfields are the dabashan uplift hannan upland and leshan longnvsi uplift the highly elevated concentrations of hfses in the coals are due to hydrothermal fluids three tonstein layers derived from alkali rhyolite were identified these tonsteins are characterized by highly enriched hfses and by strong negative eu anomalies in the rare earth element distribution patterns the major carriers of the rare earth elements in the coal are rhabdophane and silicorhabdophane the latter of which is also enriched in zr zirconium however mainly occurs in zircon rhabdophane and silicorhabdophane in the coal are mainly distributed along the bedding planes and occur as cell fillings zircon in the coal occurs as cell fillings and is of authigenic origin anatase in the partings and coals contains nb and occurs as fracture filling and colloidal forms the modes of occurrence of the above minerals indicate that they were derived from hydrothermal fluids mercury and se mainly occur in sulfide minerals pyrite and marcasite

mineralogy and geochemistry of late permian coals from the taoshuping mine yunnan province china evidences for the sources of minerals abstract this paper describes the mineralogy and geochemistry of a batch of 17 coal samples covering the late permian longtan formation from a drill core from the taoshuping mine eastern yunnan province china the results show that minerals in the coals include quartz kaolinite calcite chamosite pyrite mixed layer i s and minor marcasite siderite anatase ankerite and dolomite modes of occurrences of authigenic quartz and chamosite suggest that they were mainly precipitated from fe mg rich siliceous solution derived from the weathering of emeishan basalt which was induced by mantle plume eruption during late middle permian and covers most places of southwest china kaolinite and mixed layer i s are mainly of detrital origin correspondingly the elevated trace elements including v cr co and ni in the coals are closely related to emeishan basalt trace amounts of detrital calcite ankerite and siderite in the coals probably originated from the maokou limestone the frequent presence of high temperature quartz indicates that felsic volcanic eruption took place through the entire late permian epoch mineral matter in the coals was not only derived from emeishan basalt in the kangdian oldland but also felsic volcanic ashes mafic volcanic ashes and limestone of the maokou formation

mineral microspherules in chinese coal and their geological and environmental significance abstract studies of finer grained minerals in coal have great significance for both geology and the environment eleven coal samples of different rank were collected from different regions in china and mineral microspherules were identified in these samples by scanning electron microscopy with energy dispersive x ray spectroscopy sem edx the microspherules usually occur as regular spheres with smooth surfaces and have an average size of less than 5 m in diameter most microspherules are colloidal in origin and include phases such as fe sulfides glauconite fe hydr oxides calcium oxalate and allophane allophane is a product of colloidal al2o3 and sio2 which as a precursor of kaolinite exists ubiquitously in the coals as does kaolinite some microspherules such as garnet and sphene are mainly derived from detrital sources and a few microspherules probably result from volcanogenic ash and or from cosmic dust ultrafine na bearing minerals were also found in the coals such micro sub micro and ultrafine minerals in coal may play an important role in the formation of ultrafine coal fly ash particles

petrography and mineralogy of self burning coal wastes from anthracite mining in the el bierzo coalfield nw spain abstract coal fires burning around the world over many years have been responsible for the loss of natural resources and also for negative environmental and human health impacts study of self burning coal wastes based on organic petrology mineralogy and geochemistry allows the evaluation of factors responsible for the combustion process and can also be used to assess the changes that are taking place in thermally affected materials the main goal of this study is to characterize the materials from the arroyo galladas arroyo mourin and fabero coal waste piles which resulted from coal mining in the el bierzo coalfield nw spain samples of coal and of unburned and burned or burning coal waste material were studied by optical microscopy and x ray powder diffraction xrd the results demonstrate that some of the organic matter has preserved its characteristics but other organic material shows signs of thermal alteration such as cracks devolatilization vacuoles dark reaction rims plasticized edges and increased or decreased vitrinite reflectance the resistance of the unaltered organic matter to thermal effects is attributed to the coalification process previously undergone by these coals the mineralogical composition of the samples indicates that newly formed minerals are present in the burned or burning material including mullite cristobalite cordierite hematite jarosite sanidine anorthite sulfur pyrite rozenite coquimbite tschermigite boussingaultite and amorphous material the formation of these minerals is attributed to combustion at maximum temperatures of at least 1100 c in the fabero coal waste pile and lower temperatures in the arroyo galladas coal waste pile and to interaction of gases released by combustion with the solid particles the waters and the atmosphere in and around the waste piles

analysis origin and significance of mineral matter in coal an updated review abstract the material classed as mineral matter in coal embraces crystalline mineral materials as well as a range of inorganic elements that occur in non crystalline form this review outlines the methods that may be used to evaluate the percentage of mineral matter for a coal sample as opposed to the ash yield and to identify the minerals their individual percentages and their modes of occurrence within the coal the principal techniques include low temperature oxygen plasma ashing quantitative evaluation of x ray diffraction data observation using optical microscopy and a combination of observation chemical analysis and in some cases mapping based on scanning electron microscopy and related methods a range of other techniques may also be used to provide additional information on particular mineral matter components processes responsible for mineral matter formation include detrital input biogenic activity and authigenic precipitation at different stages of the coal s depositional and post depositional history differential migration of non mineral inorganic elements may also occur in lower rank coals and expulsion of non mineral inorganics may take place with rank advance knowledge of the mineral matter may be of assistance in understanding the modes of trace element occurrence with implications for assessing possible environmental impacts and also the potential for recovery of economic products from coal the behaviour of different mineral matter components at high temperatures is also discussed as well as methods for mineralogical analysis of ashes and other coal utilization products information from mineral matter studies may provide an improved basis for understanding coal formation and for evaluating the response of particular coals to different combustion gasification and coking processes

quantification of crystalline mineral matter in some turkish coals using interactive rietveld based x ray diffractometry quantitative x ray diffractometry using a rietveld based computational method siroquant has been carried out for a series of coal samples from the various turkish mines standard proximate and ultimate analyses were carried out chemical compositions of the high temperature ash hta of coal samples were determined by x ray fluorescence xrf spectrometry technique crystalline mineral matter and amorphous content of raw coal samples were estimated the ca si al s and fe concentrations are higher than those of the other major elements ti mn mg na p k in the studied coal samples the percentage of crystalline mineral matter for each sample varies from 16 5 to 36 1 of the coal samples the minerals in the sampled coals consist mainly of quartz clay minerals calcite pyrite and gypsum percentages of crystalline mineral matter in ash content remarkably decrease for the elbistan orhaneli and tufanbeyli lower rank coals

petrological mineralogical and geochemical compositions of early jurassic coals in the yining coalfield xinjiang china abstract the petrological geochemical and mineralogical compositions of 10 coal seams early jurassic from an exploratory borehole hole zkj502 in the jieliangzi mining area of the yining coalfield xinjiang uygur autonomous region china were investigated using optical microscopy and field emission scanning electron microscopy in conjunction with an energy dispersive x ray spectrometer fe sem eds as well as x ray powder diffraction xrd x ray fluorescence xrf and inductively coupled plasma mass spectrometry icp ms the yining coals are of subbituminous to highly volatile c bituminous in rank vitrinite reflectance average 0 49 and are characterized by low sulfur content average 0 45 low ash yield average 4 10 high volatile matter average 38 82 high proportion of inertinite average 49 5 and low concentrations of most trace elements relative to the upper continental crust the rare earth elements and yttrium in the yining coals are mainly characterized by light and heavy rey enrichment the minerals in the yining coals are dominated by quartz kaolinite and siderite followed by pyrite bassanite and hexahydrite along with small proportions of illite calcite dolomite gorceixite goyazite ankerite marcasite diaspore florencite hematite and millerite the similarity between the yining coals and the magmatic rocks from the peripheral mountain area of the basin in terms of the al 2 o 3 tio 2 ratio the rey enrichment type the rey distribution patterns and the eu anomalous fractionation suggest that the sediment source region was mainly carboniferous volcanic rocks andesite and basalts on peripheral mountains the acid conditions and lowered water table during peat accumulation may have caused detrital minerals to be leached leading to the relatively low ash yield another reason for the low ash yield may be the simple coalfield structure and poor groundwater migration channels in the rocks and coal seams in the central zone of the basin which would limit the minerals carried by the groundwater into coals a number of authigenic minerals quartz kaolinite siderite and gorceixite occur as cell fillings and elevated concentrations of li be sc v cr co ni cu zn ga rb zr nb mo cs hf w pb th and rey occur in nos 26 and 27 coals indicating that there was an injection of a small scale solution

distribution and origin of minerals in high rank coals of the south walker creek area bowen basin australia the coals of the south walker creek area in the northern bowen basin with a vitrinite reflectance rvmax of 1 7 to 1 95 are among the highest rank coals currently mined in australia x ray diffraction studies have identified an unusual mineral variation through the vertical sequence with kaolinite rich assemblages typical of other australian coals at the top and bottom of the seam section and an illite chlorite assemblage resembling a metamorphic association in the middle calcite and ankerite are also abundant in parts of the vertical sequence diaspore is abundant in the middle section of the seam in some areas and paragonite dickite or nacrite occurs in some locations as well the distribution of the non carbonate mineral assemblages cross cuts the seam stratigraphy and appears to be primarily controlled by faults and other structural features integration of the mineral distribution with optical and electron microscope data on the coal and non coal bands chemical data from coal ash analysis and information from x ray micro tomography suggests that the illite chlorite and diaspore bearing assemblages resulted from hydrothermal effects associated with fluid migration through the middle part of the coal seam this is further confirmed by the development of metamorphic textures in a tonstein band also altered to illite and chlorite in the illite rich part of the seam section in contrast to a tonstein with more normal sedimentary textures and a kaolinite composition in the kaolinite rich upper part of the seam detailed studies of cleat mineralisation suggest that fluids rich in ca mg and al were introduced relatively early in the seam s post depositional history associated with heat flow sufficient to alter the minerals in the coal and tonstein in the affected part of the seam section the relatively uniform vitrinite reflectance profile observed through the seam section may indicate that the coal was already of high rank before the fluids were introduced or that any localised heat effects on the organic matter associated with the changes in clay mineralogy were overprinted by subsequent wider ranging rank advance processes

mineralogical and geochemical anomalies of late permian coals from the fusui coalfield guangxi province southern china influences of terrigenous materials and hydrothermal fluids abstract the late permian coal in the fusui coalfield of southern china is characterized by high fe sulfide and organic sulfur contents 2 60 and 2 94 respectively trace elements including zr 354 g g on average hf 9 18 g g y and rare earth elements rey 302 g g li 97 9 g g and cs 7 02 g g are significantly enriched in these coals in addition to hg and se enrichment in the roof and floor of the coal fluorine mo and u are enriched in the roof the floor is rich in cl s fe pb and cd compared to the upper continental crust rey in the parting and coal bench samples are characterized by heavy rey and light rey enrichment respectively the coals partings and host rocks roof and floor have negative eu anomalies the coal benches have higher ratios of u th yb la nb ta and zr hf and more abundant heavy rare earth elements than their adjacent partings these geochemical anomalies are attributed to the composition of terrigenous materials derived from the yunkai upland multi stage syngenetic and epigenetic hydrothermal fluid activities and intensive leaching and re distribution of lithophile elements from partings to the underlying coal benches both the organic and sulfide sulfur are also derived mainly from the hydrothermal fluids rather than the marine influence the minerals in the samples studied including kaolinite quartz and ree bearing minerals are of both terrigenous and hydrothermal origin al oxyhydroxides crystalline feso 4 oh water bearing fe oxysulfate and goyazite were derived from the hydrothermal activity kaolinite quartz ree bearing minerals and apatite from the sediment source region were also subjected to destruction by hydrothermal fluid leaching

petrology mineralogy and geochemistry of the ge rich coal from the wulantuga ge ore deposit inner mongolia china new data and genetic implications abstract the early cretaceous wulantuga high ge coal deposit in inner mongolia is one of the major coal hosted ge deposits in china this paper reports new data on the petrological mineralogical and geochemical compositions of 13 bench samples of the high ge no 6 coal from the wulantuga deposit and provides new insight into the origin and modes of occurrence of the minerals and elements present the no 6 coal has a low rank ro max 0 45 and is a low ash coal 8 77 the total content of inertinite 52 5 vol on average in most coal benches is higher than that of huminite 46 8 vol on average the dominant huminite maceral is textinite averages 43 9 and the dominant inertinite macerals are mainly fusinite averages 33 and semifusinite 12 5 along with trace portions of intertodetrinite secretinite funginite and macrinite fungus seen as the maceral funginite played a role in the development of degraded maceral forms in the wulantuga coals funginite is present in samples examined in this study but is not easily extracted during palynological studies recovered fungal taxa are saprophytes indicating woody decomposition prior to incorporation in the mire palynology revealed a sparse flora that is consistent with the early cretaceous age minerals in the coal include quartz kaolinite illite and or illite smectite gypsum pyrite and traces of rutile and anatase a varying proportion of bassanite was observed in the low temperature ashes ltas bassanite in the ltas was derived both from the dehydration of gypsum in the raw coals and from the interaction between organically associated ca and s during the low temperature ashing in addition to a proportion of detrital quartz fine grained and cell filling quartz of authigenic origin is also present pyrite is of syngenetic origin and derived from sulfate rich hydrothermal fluids compared to common chinese and world low rank coals the no 6 coal is enriched in be 25 7 g g f 336 g g ge 274 g g as 499 g g sb 240 g g cs 5 29 g g w 115 g g hg 3 165 g g and tl 3 15 g g germanium in the coal is organically associated and its enrichment is attributed to hydrothermal fluids from the adjacent granitoids beryllium is probably associated with ca and mn bearing carbonate minerals and to a lesser extent with clay minerals rather than with organic matter fluorine largely occurs in clay minerals kaolinite and illite the elevated concentrations of tl hg as and sb are mainly distributed in pyrite and were derived from the same hydrothermal source the high w in the coal occurs in both the organic matter and the authigenic quartz illite is the major carrier of cs in the coal the accumulation of rare earth elements ree in the coals had a polygenetic and multistage nature including two syngenetic stages early hydrothermal and terrigenous and one diagenetic late hydrothermal stage the ree distribution patterns of the early hydrothermal and terrigenous stages were characterized by the enrichment of medium ree m type ree and light ree l type ree respectively a h type ree distribution pattern hree enrichment occurred in the late diagenetic hydrothermal stage the high ge wulantuga coals are also abnormally enriched in precious metals gold pt and pd in the coals calculated from their concentrations in the ltas are 3 5 25 8

mineralogy and geochemistry of a superhigh organic sulfur coal yanshan coalfield yunnan china evidence for a volcanic ash component and influence by submarine exhalation abstract the mineralogy and geochemistry of a superhigh organic sulfur shos coal of late permian age from the yanshan coalfield yunnan province southwestern china have been studied using optical microscope low temperature ashing plus x ray diffraction analysis scanning electron microscope equipped with energy dispersive x ray spectrometer a sequential chemical extraction procedure and inductively coupled plasma mass spectrometry the m9 coal from the yanshan coalfield is a shos coal that has a total sulfur content of 10 12 11 30 and an organic sulfur content of 8 77 10 30 the minerals in the coal consist mainly of high temperature quartz sanidine albite muscovite illite pyrite and trace amounts of kaolinite plagioclase akermanite rutile and dawsonite as compared with ordinary worldwide bituminous coals and anthracite and chinese coals the m9 coal is remarkably enriched in b 268 g g f 841 g g v 567 g g cr 329 g g ni 73 9 g g mo 204 g g and u 153 g g in addition elements including se 25 2 g g zr 262 g g nb 20 1 g g cd 2 07 g g and tl 2 03 g g are also enriched in the coal occurrence of high temperature quartz sanidine muscovite and illite in the m9 coal is evidence that there is a volcanic ash component in the coal that was derived from acid volcanic ashes fallen into the swamp during peat accumulation occurrence of albite and dawsonite in the coal and strong enrichment of some elements including f s v cr ni mo and u are attributed to the influence by submarine exhalation which invaded along with seawater into the anoxic peat swamp abundances of lithophile elements including rare earth elements nb y zr and tio2 indicate that the silicate minerals in the coal were derived from the northern vietnam upland to the south of the basin

elemental and mineralogical anomalies in the coal hosted ge ore deposit of lincang yunnan southwestern china key role of n2 co2 mixed hydrothermal solutions abstract the lincang neogene high ge coal deposit in yunnan southwestern china is one of the major coal hosted ge deposits in the world this study reports new data on the petrological mineralogical and geochemical compositions of 57 samples including coal bench samples roofs floors partings and batholith granite of three high ge coal seams s3 z2 and x1 from the dazhai mine lincang ge ore deposit and provides new insights into the origin and modes of occurrence of the minerals and elements present the coals have huminite random reflectances in the 0 33 0 48 range on a mineral free basis the coal samples are dominated by huminite group macerals all having more than 88 5 total huminite ulminite and attrinite generally dominate the huminite macerals structured inertinite is rare with funginite being the most abundant inertinite form the minerals in the coals are mainly composed of quartz and to a lesser extent kaolinite illite and mica a hydrous beryllium sulfate phase beso 4 4h 2 o is present in the low temperature ashes of several coal samples compared to average values for world low rank coals beryllium up to 2000 g g and 343 g g on average ge up to 2176 g g and 1590 g g on average and w up to 339 g g and 170 g g on average are unusually enriched in the lincang coals with a concentration coefficient 100 cc ratio of element concentration in investigated coals vs world low rank coals elements as 156 g g on average sb 38 g g cs 25 2 g g and u 52 5 g g are significantly enriched 10 the biotite and two mica granites which served as both the basement for the coal bearing sequence and as a source of sediment input were also either hydrothermally altered or argillized the alteration appears to have taken place during or shortly after deposition of the coal bearing sequence two types of metasomatites of hydrothermal origin including quartz carbonate and carbonate were identified which occur as partings and as roof and floor strata these metasomatites were formed at the syngenetic or early diagenetic stages of coal deposition the rare earth elements in these hydrothermal rocks are characterized by a heavy ree enrichment type and by distinct positive eu anomalies compared to the upper continental crust hydrothermal solutions have played a significant role in producing the elemental and mineralogical anomalies in the lincang ge ore deposit the hydrothermal solutions leaching the batholith granite were a mixture of alkaline n 2 bearing and volcanogenic co 2 bearing fluids which led to the enrichment of trace elements not only including assemblages of ge w and be nb u both leached from granite and the deposited in the peat but also as sb from volcanogenic solution as well as the alteration and argillization of the batholith granites and the formation of carbonate and quartz carbonate metasomatites

mineral matter in low rank coals and associated strata of the mae moh basin northern thailand abstract the mineral and other ash forming constituents in lignites of the mae moh basin in northern thailand have been identified and evaluated in relation to the minerals present in the associated interseam non coal strata and the intra seam non coal bands treatment of the coal with water ammonium acetate and hydrochloric acid shows that a considerable part of the ash forming inorganic matter occurs in water soluble acid soluble or ion exchangeable form although the distribution of elements may be modified by the effects of pyrite oxidation the mobile fraction of the fresh coal is dominated by water soluble ion exchangeable and acid soluble calcium water soluble and exchangeable magnesium water soluble sodium and sulphur and acid soluble iron and aluminium calcium is most abundant especially in coals where a low proportion of silicate minerals quartz clay etc is present it combines readily with the different sulphur forms on combustion to produce an ash with a distinctively high cao and so 3 content the main minerals in the coals are quartz pyrite and a clay fraction consisting of kaolinite illite and an expandable irregular mixed layer mineral the mixed layer clay appears to be more abundant in the coal and illite less so than in the mudrocks of the associated non coal strata the non coal partings within the main seams contain quartz pyrite and a similar clay mineral assemblage but they also contain an abundance of calcite and or aragonite and in some cases consist entirely of carbonate minerals shell fragments and possibly plant replacement structures are present in some of these materials gypsum bloedite hexahydrite and other sulphate minerals and calcite are deposited as fracture fillings and surface coatings on some exposed open cut mine faces

palaeoenvironment of seam i in the marathousa lignite mine megalopolis basin southern greece the present study aims to elucidate the depositional environment of seam i in the megalopolis basin southern greece using existing geological data supported by maceral and mineralogical analyses as well as by natural radioactivity determinations very high pyrite and uranium contents and a very low tissue preservation index usually suggest a marine influence during deposition in seam i however these features are most probably the result of a karstic aquifer supplying the palaeomire with sulphate rich neutral to weakly alkaline water the pyrite formation and the u precipitation are attributed to the anaerobic conditions which prevailed during peat accumulation the petrographic mineralogical and geochemical data of the studied profile point to several changes in the surface runoff and the supply of clastic material during deposition

mineralogy and geochemistry of late permian coals from the donglin coal mine in the nantong coalfield in chongqing southwestern china abstract the donglin coal mine an important mine in the nantong coalfield in southwestern chongqing is immediately adjacent to the songzao coalfield to investigate the mineralogy and geochemistry of donglin coals profile channel samples from the mineable nos 4 and 6 coals were collected the minerals major element oxides and trace elements were analyzed by lta xrd in combination with siroquant software xrf icp ms icp cct ms as and se ise f and dma 80 hg analyzer hg the results indicate that the donglin low volatile bituminous coals were characterized by low ash yields and high total sulfur contents the minerals varied between the nos 4 and 6 coals differentiated by montmorillonite calcite ankerite and pyrite despite the low boron concentration donglin coals were influenced by brackish water during coal accumulation selenium 10 9 mg kg f 431 mg kg hg 0 350 mg kg nb 20 7 mg kg and ta 3 68 mg kg in the no 4 coals and f 425 mg kg be 7 11 mg kg ga 14 5 mg kg ge 22 5 mg kg zr 218 mg kg nb 35 5 mg kg and ta 4 42 mg kg in the no 6 coals are slightly enriched four vertical distributions of elements were demonstrated i e roof floor roof and floor and middle enrichments the slightly enriched trace elements and ucc normalized rey distribution patterns of the donglin coals jointly eliminated the impact of various volcanic ashes and terrigenous input from the kangdian oldland during the late permian however the roof rock samples shared the geochemical feature of mafic tonstein enriched sc v cr co and ni while the floor rock of the no 6 coals resembles alkali tonsteins enriched ga zr nb ta hf and rey lithium ga zr ag cd in sn cs hf bi th and u occurred in kaolinite and or montmorillonite in the no 4 coals while li nb ag cd in cs ba and th occurred in kaolinite in the no 6 coals vanadium sr and mo in the no 4 coals and sr and sc in the no 6 coals were associated with calcite and or ankerite arsenic se hg sb and tl and hg and mo were associated with pyrite in the nos 4 and 6 coals respectively lithium be ge and sb in the no 4 coals and be and ge in the no 6 coals might be of organic affinity

mississippian anthracites in guangxi province southern china petrological mineralogical and rare earth element evidence for high temperature solutions abstract minerals and elements in coal are derived from the processes associated with peat accumulation and rank advance as well as possibly a range of epigenetic processes and thus can provide information on the depositional conditions and geologic history of coal beds and coal bearing sequences as well as perhaps on regional tectonics this paper investigates the petrology mineralogy and geochemistry of anthracites and their host rocks partings roof and floor strata from two coal deposits hongmao and luocheng in guangxi province southern china samples collected from these deposits were analyzed using optical microscopy scanning electron microscopy plus energy dispersive x ray spectrometry low temperature ashing x ray diffraction x ray fluorescence spectrometry and quadrupole based inductively coupled plasma mass spectrometry the anthracites from the two deposits are medium to high sulfur coals the rare earth elements in the luocheng anthracites are characterized by distinct positive eu anomalies and medium and heavy ree enrichment types the minerals in the hongmao anthracites are characterized by the occurrence of k illite paragonite and ammonian illite which however are absent in the luocheng anthracites the paragonite ammonian illite and chlorite resulted from the alteration of pre existing kaolinite by hot solutions containing na nh4 and fe2 respectively the partings in the luocheng anthracite seams contain pyrophyllite that was formed by reactions between kaolinite and quartz during injection of high temperature solutions the mineralogical and geochemical characteristics of the anthracites in the two deposits indicate that the coals were subjected to high temperature 250 c solutions that also elevated the coal rank to anthracite grade the assemblage of k illite paragonite nh4 illite in the coals of the hongmao deposit was formed under greater hydrothermal but less tectonic influence compared to the luocheng deposit by contrast the pyrophyllite illite chlorite assemblage of the luocheng deposit reflects a greater tectonic but lesser hydrothermal influence

quantitative evaluation of minerals in coal deposits in the witbank and highveld coalfields and the potential impact on acid mine drainage abstract this study has investigated the quantitative distribution of minerals in coals and other lithological units in the coal bearing successions of the witbank and highveld coalfields in the mpumalanga province of south africa using low temperature oxygen plasma ashing lta high temperature ashing x ray diffraction and x ray fluorescence spectrometry techniques mineral matter makes up approximately 8 to 35 wt of the coal samples sio 2 concentrations in the coal vary between 0 0 and 35 0 wt al 2 o 3 between 0 5 and 16 0 wt fe 2 o 3 between 0 03 and 10 0 wt and s between 0 15 and 8 0 wt minor concentrations of cao 0 0 to 8 0 wt and mgo 0 0 to 1 0 wt are also present p 2 o 5 occurs in concentrations of 0 0 to 3 5 wt and k 2 o is in the order of 0 0 to 1 3 wt na 2 o varies between 0 0 and 0 45 wt with the highveld coals showing an enrichment in na 2 o 0 0 to 0 51 wt in comparison with the witbank coals the minerals in the coals are dominated by quartz and kaolinite with varying proportions of calcite dolomite and pyrite as well as accessory phosphate phases higher normalised k 2 o and na 2 o concentrations are present in the sandstones than in the associated siltstones and carbonaceous shales partly reflecting the presence of feldspars and clay minerals such as illite acid base accounting was used to investigate the potential of the coal and coal bearing units to produce acid mine drainage conditions according to the screening criteria all the coal and coal bearing units except the unit between the no 1 and no 2 coal seams are potentially acid generating the average net neutralising potential nnp values suggest that the no 5 coal seam the no 4 upper coal seam and the unit between the no 4 and no 2 coal seams are potentially acid generating with such techniques it is possible to predict the types of situations that might arise concerning groundwater quality and implement proper prevention or remediation programs

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 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 g g ga 16 3 g g zr 446 g g ba 276 g g hg 0 33 g g and th 12 4 g 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 late permian coals and host rocks from the guxu coalfield sichuan province china with emphasis on enrichment of rare metals abstract this paper reports the geochemical and mineralogical compositions of the late permian no 25 coal semi anthracite and its host rocks roof and floor strata from the guxu gulin xuyong coalfield sichuan province china the coal is characterized by medium sulfur content average 2 73 and has an average ash yield of 20 95 in contrast to other late permian coals from southwestern china that are enriched in sc v cr co ni and cu the no 25 coal does not contain an abundance of these transition elements but is rich in lithophile elements be y nb zr hf and u the elevated concentrations of trace elements in the no 25 coal were probably derived from the felsic intermediate rocks at the top of the emeishan basalt sequence rather than from the emeishan mafic basalts the floor strata of the no 25 coal can be divided into two sub sections the upper sub section of the sequence immediately below the no 25 coal consists of material with a felsic intermediate composition probably derived from terrigenous sources and the lower sub section is composed of mafic tuff the terrigenous mineral matter in the no 25 coal appears to have the same sediment source region as the upper sub section of the floor strata based on their similar geochemical compositions the roof strata of the no 25 coal are more quartzose and were probably derived from a different sediment source region the mineral matter in the coal is dominated by kaolinite and to a lesser extent calcite and pyrite the roof and floor strata each have quite different mineralogy with kaolinite dominant in the latter and illite kaolinite and quartz in the former pyrite contents are variable both in the coal and in the host rocks the floor strata and the coal have been affected by hydrothermal solutions leading to the enrichment of rare earth elements and yttrium rey nb ta zr hf and u the rey in the coal and floor strata as well as the nb ta zr hf and u in the floor strata represent potentially economic rare metal resources

mineral matter in triassic and tertiary low rank coals from south australia abstract the minerals and non mineral inorganic constituents in triassic and tertiary low rank coals from various coal deposits in south australia were studied using selective chemical leaching and oxygen plasma ashing techniques although gypsum may be present in some samples most of the sodium calcium and magnesium as well as part of the sulphur appears to occur as a combination of dissolved ions in pore water and exchangeable ions attached to carboxylate groups significant concentrations of iron and aluminium occur in acid soluble form probably as organometallic complexes within the hydrocarbon structure quartz is the dominant mineral in the tertiary coal samples it appears to be mainly detrital but doubly terminated euhedral crystals suggest an authigenic origin in one of the deposits well crystallized kaolinite is common in the triassic coals while poorly crystallized kaolinite occurs in the tertiary samples siderite calcite and possibly collophane occur in the triassic coals sparse pyrite is present in both the tertiary and the triassic samples the differences in minerals and other inorganic constituents between the tertiary and triassic deposits can be explained partly by variations in the composition of the pore waters permeating the strata and partly by mobility of silica and alumina from different sources within the peat deposit the relative mobility of the different inorganic constituents is also significant in beneficiation of the coal for use in combustion processes

new data on geology and germanium mineralization in the hunchun basin northeastern china abstract the geochemistry and mineralogy of palaeogene coals from the hunchun coalfield jilin province northeastern china have been studied using x ray fluorescence spectrometry inductively coupled plasma mass spectrometry scanning electron microscopy in combination with energy dispersive x ray spectrometry and x ray diffraction analysis of the low temperature ash the 22a coal from the banshi mine is of subbituminous a to high volatile bituminous rank 0 53 0 56 ro ran and has a low sulfur content 0 74 on average the 22a coal consists mainly of kaolinite quartz illite and to a lesser extent plagioclase siderite and pyrite as compared with the average world low rank coals the 22a coal is enriched in as sb ge cs and w combined with the geochemical features of six other coal seams from the hunchun coalfield the terrigenous materials of the hunchun coals were dominantly from mesozoic mostly lower cretaceous volcanic rocks and paleozoic granites and associated metamorphic rocks surrounding the coal basin a minor source was the paleogene volcaniclastics including some adakitic rocks which are characterized by higher sr y and la yb ratios the ge enrichments that are detected in some individual coal benches from the hunchun coalfield were related to tectonic uplift of the crystalline rocks surrounding the basin and their following denudation the oxidized meteoric waters episodically influenced by volcanic related hot springs might extract ge from the source rocks and then precipitate it as a result of bio chemical reduction forming the mineralization disseminated in the coals

mineralogical and geochemical compositions of the coal in the guanbanwusu mine inner mongolia china further evidence for the existence of an al ga and ree ore deposit in the jungar coalfield abstract aluminum hydroxide boehmite and diaspore ga rey rare earth elements and y and al rich pennsylvanian taiyuan formation coals have previously been found in the jungar and daqingshan coalfields inner mongolia china gallium rey and al are potentially extractable and usable elements in combustion residues derived from these coals this paper reports new results on 50 bench samples of the no 6 coal from the guanbanwusu mine jungar coalfield inner mongolia and provides new data and evidence for the existence of an al ga rey ore deposit in the unique jungar coalfield the no 6 coal in the guanbanwusu mine has a low rank ro ran 0 56 and a low sulfur content st d 0 58 the proportion of inertinite in the coal 56 7 mineral free basis is higher than that of vitrinite 31 the minerals in the coal are mainly represented by kaolinite boehmite and chlorite along with variable proportions in some samples of calcite ankerite siderite and goyazite boehmite goyazite and part of the kaolinite were derived from bauxite in the weathered surface of the sediment source region ankerite calcite and siderite in the coal are of authigenic origin the chlorite in the guanbanwusu coals appears to have a chemical composition intermediate between cookeite and chamosite this mineral mainly occurs as cell fillings also indicating an authigenic origin and was probably derived from hydrothermal fluids a new mineral phase mainly composed of ti cl and fe is probably a ti bearing oxychloride or hydroxychloride compared to other chinese coals and to world hard coals the coal from the guanbanwusu mine is enriched in al2o3 9 34 p2o5 0 126 li 175 g g f 434 g g cl 1542 g g ga 12 9 g g sr 703 g g and th 12 9 g g but has a lower sio2 al2o3 ratio 0 74 due to the higher proportions of boehmite and goyazite in the coal the major carrier of p2o5 and sr is goyazite lithium mainly occurs in the chlorite cf cookeite kaolinite and possibly to a lesser extent illite fluorine in the coal has a major boehmite affinity but a small proportion may also occur in the organic matter and chlorite gallium in the coal largely occurs in goyazite chlorine is independent of other elements in the coal associated neither with moisture nor with organic matter but possibly occurring in molecular form cl2 and in the ti bearing oxychloride or hydroxychloride thorium in the coal occurs in the clay and accessory minerals and was mainly derived from detrital materials of the source region rare earth elements and y have a mixed organic and inorganic affinity largely occurring in goyazite group minerals and to a lesser extent boehmite and organic matter most coal benches and partings have either an l type or h type of rey enrichment owing respectively to the weathered bauxite source region and groundwater effects the al2o3 ga rey and possibly li in the guanbanwusu coals like those in coals from the jungar and adjacent daqingshan coalfields are industrially useful metals that could potentially be recovered from the relevant coal combustion residues it is suggested that if ga in ash 50 g g rey 800 900 g g sio2 al2o3 40 in ash and coal thickness 5 m the coal combustion residues would be expected to be suitably enriched in al2o3 and can be considered for al2o3 ga and rey recovery

high resolution three dimensional imaging of coal using microfocus x ray computed tomography with special reference to modes of mineral occurrence abstract samples of coal from the sydney and bowen basins of eastern australia have been imaged at high resolution using a large field 3d microfocus x ray computed tomography ct system with special but not exclusive attention to evaluating the modes of occurrence of the mineral matter within the coal the samples imaged were 110 mm 25 mm 19 mm 10 mm and 4 mm in size yielding voxel dimensions of 54 30 12 6 and 3 m respectively data collection was carried out using a helical stage providing images with 20002 voxels in the horizontal x y plane and up to 3500 voxels high three dimensional image blocks derived from the scans were examined as cross sections along orthogonal planes and as perspective images manipulated to be viewed from any angle imaging after saturating the coal with x ray attenuating brine was also carried out to highlight the distribution of connected micro pores and cleats and improve the detail of features seen within the samples features evaluated within the coals included the size and three dimensional distribution of siderite nodules and different types of mineral infillings in petrifactions of maceral components individual macerals could also be identified within the coal based partly on x ray density and partly on the associated porosity and structure in some cases high resolution images enabled the nature of individual plant particles to be identified within the coal samples mineral filled cleats and open fractures were also evaluated including the origin of radiating fracture patterns around siderite nodules in vitrinite in some cases several generations of cleat and or fractures could be distinguished and the sequence of their formation and infilling was interpreted complementary analyses of the mineral matter in the samples were carried out using x ray diffraction as well as examination of polished sections by optical microscopy examination images obtained from the ct scans were also registered against sem edx and qemscan images of polished sections prepared from the same samples after scanning providing a more definitive basis for identifying the different components and for integrating ct data with results from other petrographic and electron microscope studies

a more accurate method for estimating in situ coal density and mineral matter from ash and specific energy determinations abstract the estimation of in situ coal density has been the subject of extensive research due to its importance for coal reserve estimation however despite decades of studies a universal method for density estimation that can be applied to all coal deposits still does not exist traditional ash based methods are inaccurate because ash is a combustion product that does not contain the volatile mineral components which are lost upon combustion coal is composed of three primary constituents organic macerals inorganic mineral matter and moisture understanding the properties of the mineral matter is particularly critical for accurate density estimation the method described herein improves the accuracy of density estimates by first estimating the mineral matter percentage of each sample using only ash and specific energy analyses both of which are performed on the large majority of exploration samples a least squares hyperbolic formula is derived from the dry coal and mineral properties in order to estimate the dry sample density the formula accepts two in situ moisture percentages for both coal and rock in order to estimate in situ density for coal and other lithologies this method has several advantages over existing techniques it is valid for all values of ash with no loss in accuracy outside a limited range the scatter caused by mineral volatiles is reduced resulting in a much higher correlation coefficient coal and mineral densities derived from the formula may also provide insight into the coal maceral and mineral types present within a project as well as changes in mineralogy with ash content

mineralogy of lignites and associated strata in the mavropigi field of the ptolemais basin northern greece the mineralogy of five lignite layers and the associated roof floor and intercalating strata has been analysed using low temperature oxygen plasma ashing and quantitative x ray diffraction techniques the lignite contains quartz kaolinite illite and smectite and in some cases small proportions of feldspar thought to represent mainly detrital minerals in the original peat deposits one sample also contains crystalline calcium oxalates with weddellite present in the raw lignite and whewellite in the low temperature ash lta of the same lignite sample minor proportions of gypsum are present in some of the raw lignite samples possibly in part derived from precipitation of dissolved ca and so4 in the pore waters on drying all the ltas however contain much higher proportions of bassanite and or gypsum compared to the other minerals present consistent with production of calcium sulphate artefacts from interaction of abundant organically associated ca and s in the lignite during the plasma ashing procedure the inorganic strata are mainly carbonate rocks consisting almost entirely of calcite with minor aragonite small proportions of illite traces of pyrite and in some cases siderite some non carbonate rocks are also associated with the lignite seams these are dominated by plagioclase feldspar and mica along with illite kaolinite and a relatively minor proportion of quartz the mineral assemblages can be related to the palaeoenvironmental conditions under which the various sediments including lignite were deposited comparison of the mineral abundances in the samples to the chemical composition of the materials shows that the quantitative xrd technique provides results consistent with ash analysis data although abundant in the associated rocks calcite does not occur in the lignite samples while part of the relatively abundant ca in the lignite occurs as either gypsum or weddellite most of it appears to be organically bound mine products that incorporate calcareous rocks of the type associated with the lignite may however contain separate calcite phases and display high carbonate co2 contents

mineralogical and geochemical responses of coal to igneous intrusion in the pansan coal mine of the huainan coalfield anhui china the huainan coalfield where magma is commonly intruded into the coal measures in the northern section e g the zhuji dingji pansan and panbei mines is the largest energy base in eastern china to investigate the mineralogical and geochemical responses of coal to igneous intrusion minerals major and trace elements in sandstone thermally altered coal igneous rock sandy mudstone and unaltered coal samples were collected from a representative profile of the no 1 coal of the pansan coal mine the samples were analyzed using an optical microscope powder x ray diffraction scanning electron microscopy in conjunction with x ray energy dispersive spectroscopy x ray fluorescence inductively coupled plasma atomic emission spectrometry and mass spectrometry the results indicated that the thick sill transformed from mafic rocks at the bottom via intermediate rocks in the middle to felsic rocks at the top of the profile the moisture total sulfur and carbon contents of the coal increased whereas volatile matter hydrogen and nitrogen decreased during contact metamorphism caused by igneous intrusion epigenetic minerals i e dolomite quartz and pyrite occurred in the thermally altered coals three stages of hydrothermal fluids i e ca mg and fe rich si rich and fe and or h2s rich solutions were identified iron ca s si mg zn cd and pb were transported into the thermally altered coal by hydrothermal fluids the concentrations of co and ni in the thermally altered coal increased in relation to the increase of ash yields that were caused by contact metamorphism whereas the b in the coal was volatilized manganese is directly related to the intrusive magma phosphorus ge and sr might be introduced into the coal by groundwater however k na ga and ba were leached out titanium sc cr v cu zr nb and rare earth elements and yttrium rey in the coals originated from terrigenous input and were not influenced by igneous intrusion

quantitative mineralogical analysis of coals from the callide basin queensland australia using x ray diffractometry and normative interpretation abstract comparisons are presented between the results of quantitative x ray diffractometry using a rietveld based computational method siroquant on low temperature ash lta and normative calculation from chemical analysis of high temperature ash for a series of coal samples from the callide basin of queensland mineral percentages indicated by each method are also compared to the results of conventional x ray diffractometry on low temperature ash spiked with a known proportion of corundum evaluated in conjunction with detailed clay mineral analysis of the for species where direct comparison is possible the proportions of the different minerals in the crystalline fraction indicated by siroquant are similar to those indicated by normative analysis using a computational procedure referred to as sednorm more conventional xrd study of spiked lta materials with the samples studied seems to underestimate quartz and siderite content and by default overestimate kaolinite siroquant on the other hand tends to overestimate the proportion of ca bearing minerals relative to the ca content of the high temperature ash processed using the sednorm computation both the siroquant analysis and the normative evaluation of sednorm provide significantly more quantitative information on coal mineralogy than other more commonly used techniques

mineral matter and trace elements in coals of the gunnedah basin new south wales australia abstract the concentrations of major and trace inorganic elements in a succession of permian coals from the gunnedah basin new south wales have been determined by x ray fluorescence techniques applied to both whole coal and high temperature ash samples the results have been evaluated in the light of quantitative data on the minerals in the same coals determined from x ray diffraction study of whole coal samples using a rietveld based interpretation program siroquant to determine relationships of the trace elements in the coals to the mineral species present comparison of the chemical composition of the coal ash interpreted from the quantitative mineralogical study to the actual ash composition determined by xrf analysis shows a high degree of consistency confirming the validity of the xrd interpretations for the gunnedah basin materials quartz illite and other minerals of detrital origin dominate the coals in the upper part of the sequence whereas authigenic kaolinite is abundant in coals from the lower part of the permian succession these minerals are all reduced in abundance however and pyrite is a dominant constituent in coals formed under marine influence at several stratigraphic levels calcite and dolomite occur as cleat and fracture infillings mostly in seams near the top and bottom of the sequence the potassium bearing minerals in the detrital fraction are associated with significant concentrations of rubidium and the authigenic kaolinite with relatively high proportions of titanium zirconium is also abundant with associated p and hf in the gunnedah basin coal seams relationships exhibited by ti zr nd and y are consistent with derivation of the original sediment admixed with the seams from an acid volcanic source pyrite in the coals is associated with high concentrations of arsenic and minor proportions of thallium no other element commonly associated with sulphides in coals however appears to occur in significant proportions with the pyrite in the sample suite small concentrations of cl present in the coal are inversely related to the pyrite content and appear to represent ion exchange components associated with the organic matter strontium and barium are strongly associated with the cleat filling carbonate minerals ge and ga appear to be related to each other and to the coal s organic matter cr and v are also related to each other as are ce la nd and pr but none of these show any relationship to the organic matter or a particular mineral component

mode of occurrence of trace elements in the pellana lignite se peloponnese greece mineralogical and geochemical analyses of the pellana lignite se peloponnese greece were carried out in order to predict the mode of occurrence of trace elements and their mobility during lignite combustion for power generation lignite and ash samples after combustion at 750 c of two cores from this deposit were examined the mean ash content is 30 to 43 and c contents on dry ash free basis range from 45 to 60 respectively the mineral phases contained in the lignite are quartz k feldspars mixed layer clays illite rich micas gypsum and pyrite factor analysis on geochemical data shows that the elements as ba mn mo sb se sr u and v have both organic and inorganic affiliation to study the mobility of each element during combustion the relative enrichment factor was calculated the most depleted and hence the most mobile elements proved to be hf nb and sb while se ba and bi are moderately depleted in case of the pellana lignite utilization we should expect environmental problems associated with the elements as ba bi hf mn mo nb sb and se these elements may be either volatilized during combustion or leached from fly ash disposal areas into underground waters causing severe environmental and health impacts

mineralogy and geochemistry of the no 6 coal pennsylvanian in the junger coalfield ordos basin china abstract this paper discusses the mineralogy and geochemistry of the no 6 coal pennsylvanian in the junger coalfield ordos basin china the results show that the vitrinite reflectance 0 58 is lowest and the proportions of inertinite and liptinite 37 4 and 7 1 respectively in the no 6 coal of the junger coalfield are highest among all of the late paleozoic coals in the ordos basin the no 6 coal may be divided vertically into four sections based on their mineral compositions and elemental concentrations a high boehmite content mean 6 1 was identified in the no 6 coal the minerals associated with the boehmite in the coal include goyazite rutile zircon and pb bearing minerals galena clausthalite and selenio galena the boehmite is derived from weathered and oxidized bauxite in the weathered crust of the underlying benxi formation pennsylvanian a high pb bearing mineral content of samples zg6 2 and zg6 3 is likely of hydrothermal origin the no 6 coal is enriched in ga 44 8 g g se 8 2 g g sr 423 g g zr 234 g g rees 193 3 g g hg 0 35 g g pb 35 7 g g and th 17 8 g g gallium and th in the no 6 coal mainly occur in boehmite and the pb bearing selenide and sulfide minerals contribute not only to se and pb contents in the coal but also probably to hg content a high zr content is attributed to the presence of zircon and sr is related to goyazite the rees in the coal are supplied from the sediment source region and the rees leached from the adjacent partings by groundwater

minerals in bituminous coals of the sydney basin australia and the illinois basin u s a although other forms of inorganic components may be significant in lower rank coals the mineral matter in most bituminous coals is dominated by silicates carbonates sulphides phosphates and other crystalline mineral groups these may be present in various forms including thin bands and laminae intimately associated with the organic matter as well as lenticles nodules crystal aggregates and cell infillings all of which indicate approximately contemporaneous formation with the peat bed other minerals however occur as veins or cleat and fracture fillings indicating precipitation after most of the compaction and presumably after most of the rank advance ome of the penecontemporaneous mineral matter is of detrital origin representing epiclastic or pyroclastic particles washed or blown into the peat swamp other mineral matter however including much of the pyrite quartz and siderite as well as abundant well crystallized kaolinite appears to have been formed by precipitation processes either within the swamp waters or in the pores of the peat deposit pyrite largely formed by bacterial reduction of dissolved sulphate ions seems to be related in abundance to marine transgressions which allowed permeation of sea water into the swamp and through the peat bed beneath siderite appears to form in the absence of sulphate rich sea water probably from co2 released by organic decay the clay fraction of the noncoal rocks in many coal bearing sequences is typically dominated by illite or interstratified clay minerals with kaolinite chlorite and possibly montmorillonite also present to a variable though typically minor extent although perhaps modified by chemical reactions or ion exchange mechanisms in the peat swamp these clay minerals may also be present in the coal as well especially near the base of top of the seam the kaolinite in the noncoal rocks is usually poorly crystallized and typically a minor constituent but well crystallized kaolinite is characteristically present and often the dominant component in the mineral fraction of bituminous coal beds as well as in some of the lutites including underclays intimately associated with the seams a progressive upward gradation to a particularly kaolinite dominated mineral assemblage occurs in some seams of the sydney basin australia this gradation is thought to be due to either increased blockage of detrital contaminants as the swamp developed or to in situ chemical or biological leaching of the mineral fraction and reconstitution of the residues in the upper parts of the peat bed superimposition of such cycles is also noted within the seam in some instances suggesting repetition of several phases of this type during major peat accumulations

quantification of mineral matter in the argonne premium coals using interactive rietveld based x ray diffraction abstract the mineral matter in the eight reference north american coal samples of the argonne premium coal series has been investigated on a quantitative basis using x ray diffraction xrd techniques x ray diffraction data obtained from electronic low temperature oxygen plasma ash lta residues from ashes produced by heating the coals in air at 370 c and also from the raw coals themselves were evaluated using an interactive data processing system siroquant based on rietveld interpretation methods the results from the three types of material lta 370 c ash and raw coal were compared for each sample this allowed the components present in the raw coals in crystalline form to be recognised separately from mineral artifacts produced particularly in the low rank coals from interaction of organically associated elements ca s etc during the two ashing processes after the allowance for the production of any artifacts the quantitative mineral assemblages identified from xrd of the raw coals were found to be consistent even for coals having a relatively low ash percentage around 5 with the results obtained from the respective mineral concentrates prepared by the ashing methods the effects of heating the coal to 370 c could also be distinguished relative to the raw coal or the lta through changes in components such as pyrite and the clay minerals although some areas of uncertainty exist particularly with magnesium in the low rank coals the calculated chemical compositions of the coal ash derived from the mineral mixtures identified for each coal were also found to be consistent with the results of direct chemical analysis of the respective coal ash materials

a comparison of quasigeostrophic and nonquasigeostrophic vertical motions for a model simulated rapidly intensifying marine extratropical cyclone abstract large scale departures from quasigeostrophic vertical motions are diagnosed for a model simulation of the qe ii storm 9 11 september 1978 the simulation was performed by the limited area mesoscale prediction system lamps initialized at 1200 utc 9 september 1978 the model cyclone intensified from a central pressure of 1003 mb to 976 mb in 24 h considerably short of the 59 mb 24 h 1 observed deepening but reasonable in comparison to other model simulations of this storm this diagnosis centers on a hydrostatic generalized omega equation which scales to the quasigeostiophic omega equation for small rossby number vertical motions were computed both from this generalized omega equation and the quasigeostrophic omega equation in order to examine the importance of nonquasigeostrophic effects the high correlation of vertical motions from a control experiment using most of the terms in the generalized omega equation with the vertical motions predicted by the model establishes the validity o

elements and phosphorus minerals in the middle jurassic inertinite rich coals of the muli coalfield on the tibetan plateau 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 g g on average p 2349 g g sr 526 g g and ba 790 g 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

mineralogy and geochemistry of the palaeogene low rank coal from the baise coalfield guangxi province china abstract some previous studies have investigated the enrichment origin of sb and cs in coal but strong supportive evidence for the sources of the two elements in coal is still absent the main aims of this study were to provide a better understanding of the geochemical and mineralogical characteristics of the palaeogene no 5 coal from the zhoujing coal mine baise coalfield guangxi province southwestern china the no 5 coal has a low rank 0 44 ro max 46 96 volatile matter content an average ash yield 19 37 and a medium sulfur content 1 23 on average the main minerals in the no 5 coal are kaolinite illite quartz and pyrite bassanite 2caso4 h2o was identified in the low temperature ashes in varying proportions 2 7 37 6 the mineralogy of the non coal samples partings roof and floor strata is similar to that of the coals but chlorite is additionally present and pyrite is largely absent in these non coal samples the modes of calcite occurrence in the partings indicates a terrigenous origin for this phase compared with average values for world low rank coals the no 5 coal is distinctively enriched in sb 29 12 g g cs 9 71 g g and u 15 61 g g compared with the average values for world clays the parting and host rock samples have normal concentrations for most trace elements with an exception of higher sb 9 93 g g the elevated sb and cs in the coal were derived from the detrital material shedding from the exposed middle triassic strata which host notable au and sb deposits in the surrounding region the rey rare earth elements and y distribution patterns for the coal benches partings roof and floor strata are generally characterized by enrichment in medium rey and positive gd anomalies both of which were due to acidic waters circulating within the coal basin the mineral compositions and their association indicate that the depositional environment was weakly acidic at the early stage of peat accumulation and then changed to neutral or weakly alkaline in the later stage

flow structures and mineralisation in thermally altered coal from the moatize basin mozambique abstract this paper examines changes in structural and petrographic characteristics of organic and inorganic matter developed in a cored 35 m thick permian coal seam from the moatize basin mozambique in proximity to an early jurassic intrusive igneous body megascopic and microscopic examinations of hand samples and polished blocks respectively were carried out to characterise the deformation and petrographic changes of the coal sem eds analysis was used for mineral identification and modes of occurrence the upper part of the core is thermally altered exhibiting intense megascopic folding of the bedding at microscopic level vitrinite presents an incipient mosaic coke texture semi coke whereas fusinite and semifusinite layers are deformed exhibiting folded structures coal petrographic characteristics suggests the temperature in the coal at this location reached no higher than 400 c but was enough for softening and ductile deformation of bands to occur apart from epigenetic chamosite occurring exclusively in the upper section and monazite that appears only in the lower section of the core microscopic studies showed similar distribution of the mineral species in both sections of the seam except with a change in their mode of occurrence detrital or syngenetic minerals in the lower section of the seam occur also as epigenetic in the thermally affected upper section siderite occurs as syngenetic nodules in the lower section but appears as epigenetic fracture filling developed with the cooling of the organic material in the upper section quartz occurs as detrital grains in the lower section whereas in the upper section this mineral occurs also as an epigenetic euhedral mineral filling the fracture system fluorapatite occurs as detrital syngenetic and euhedral epigenetic the mineralisation in the fractures also gives indications about the fluid circulation associated with the magmatic intrusion at least three stages of hydrothermal fluids were distinguished from the first to the last stage a p f and si rich fluid an fe ca mg rich fluid and an al si rich fluid these fluids gave origin to the minerals in the fractures and to some of the minerals inside the cell lumina of the inertinite macerals given the euhedral shape of some of the epigenetic minerals there was sufficient time for them to grow into euhedral forms

quantitative mineralogy of sandstones by x ray diffractometry and normative analysis abstract quantitative x ray diffraction normative calculation and whole rock chemical analysis have been compared for permo triassic quartz lithic to litho feldspathic sandstones from eastern australia the quantitative xrd technique provides mineralogical percentages that correlate well with the chemical composition of the sandstones and also with most of the mineral percentages derived from normative calculation the need for assumptions on potassium distribution between minerals provides a limitation on estimates of k feldspar and illite using the normative technique although these can be improved on a sample specific basis if necessary using complementary thin section observations or qualitative x ray diffractograms quantitative xrd analysis possibly indicates a small proportion of amorphous material in some of the sandstones especially materials with abundant lithic fragments or clay minerals but the proportion of any amorphous material overall is probably negligible both quantitative xrd and normative calculation avoid problems associated with sample heterogeneity or operator inconsistency that may affect point counting of thin sections they can also be used to provide quantitative information on sediments with abundant rock fragments or matrix components the actual mineralogy of which is not resolvable in conventional microscope investigations

composition and mode of occurrence of mineral matter in some colombian coals abstract the minerals in a range of colombian coal samples selected to represent the principal coal mining regions have been investigated using low temperature ashing and quantitative x ray diffraction techniques and the results compared to information from chemical analysis and mossbauer spectroscopy studies kaolinite illite interstratified illite smectite and quartz are the dominant mineral matter components in almost all of the coal samples with small but significant proportions of pyrite up to around 15 of the mineral matter being present in around half of the samples studied other minerals present in particular samples include chlorite muscovite paragonite ankerite dolomite calcite and siderite along with phosphate minerals apatite and goyazite jarosite and coquimbite are also noted in some of the pyrite bearing coals probably representing oxidation products of the pyrite developed with exposure or storage bassanite is present in the low temperature ash of some coals and in one sample occurs along with significant concentrations of hexahydrite alunogen tschermigite and paraluminite all of which were probably derived from interaction of inorganic elements in the organic matter with organic sulphur during maceral oxidation quantitative analysis of the minerals in the low temperature ash of the coal samples using rietveld based x ray diffraction techniques provides results that are consistent at least for the most abundant elements with the chemical composition of the coal ash as determined by standard analysis procedures the evaluation of mineral rich concentrates by mossbauer spectroscopy also provides results consistent with the xrd data especially as regards pyrite and some of the sulphate components optical microscopy indicates that much of the pyrite and in some cases also the carbonates occurs as anhedral crystals finely disseminated in the maceral components as aggregates of crystals including pyrite framboids as fine grained crystals replacing liptinite and as fracture fillings some sub angular to rounded quartz grains are also present possibly of detrital origin but most other minerals including the clay minerals occur mainly as aggregates of intimately admixed mineral and maceral constituents

petrological geochemical and mineralogical compositions of the low ge coals from the shengli coalfield china a comparative study with ge rich coals and a formation model for coal hosted ge ore deposit abstract to better understand the formation mechanism of coal hosted ge ore deposits this paper reports on the petrological mineralogical and geochemical compositions of the low ge coals in the shengli coalfield inner mongolia china using optical microscopy field emission scanning electron microscopy x ray fluorescence x ray diffraction and inductively coupled plasma mass spectrometry the samples in the present study closely neighbor the previously reported wulantuga coal hosted ge ore deposit both no 6 coal in comparison with the wulantuga ge rich coals the low ge coals of the shengli field display higher moisture 27 59 on average and lower pyritic sulfur contents 0 53 both the low ge and ge rich coals are generally high in inertinite and have varying but relatively low huminite contents preservation of fecal pellets as macrinite is notable in both the low ge and ge rich coals and the position of the fecal pellets appears to be within tunnels or chambers within the wood quartz kaolinite pyrite and gypsum are the major crystalline phases identified in most of the ge rich and low ge coals but the low ge coals contain significantly less pyrite and are more abundant in non mineral ca and mg ca oxalate of authigenic origin is observed generally occurring as cell fillings in the low ge coals otherwise mineral free organic matter in the low ge coals would be expected to have an inherent ash yield of around 6 derived from the inorganic elements mainly non mineral ca and mg that occur either in the organic matter or as dissolved ions in the pore water and form the sulfate species in low temperature oxygen plasma ash residues the highly elevated trace elements including be ge as sb w hg and tl that occur in the ge rich coals of the wulantuga deposit are significantly depleted in the low ge coals lateral migration of ge w and as hg sb tl rich solutions through the original peat swamp for the wulantuga ge ore deposit has led to significant enrichment of ge on the margin of the coal basin but decreasing ge concentrations toward to the inner part of the basin such a migration direction is different to those in the previously reported for the hydrothermal solutions in the lincang yunnan of china and spetzugli russian far east ge ore deposits where the solutions migrated vertically from granite to peat along faults and led to a dome shaped ge distribution in the relevant coal seam

mineralogy of the volcanic influenced great northern coal seam in the sydney basin australia abstract the mineralogy of the individual coal plies and intra seam claystone bands in the great northern seam of the sydney basin has been evaluated using optical and scanning electron microscopy and quantitative x ray diffraction techniques the uppermost two claystone bands are tonsteins consisting mainly of well ordered kaolinite with graupen to vermicular textures idiomorphic crystals of k feldspar within these tonsteins may represent members of the anorthoclase sanidine series or a sodic sanidine and indicate an acid to intermediate volcanic ash input in contrast the lowermost parting was largely derived from epiclastic sediment admixed with minor volcanic material such as high temperature quartz and a different type of k feldspar component the mineral fraction of the coals especially in the middle and upper parts of the seam is dominated by authigenic kaolinite with a very low abundance of quartz apart from the tonsteins authigenic processes therefore appear to be the dominant mechanism of mineral matter formation authigenic k feldspar also occurs in the lower few metres of the seam with a variety of modes of occurrence including cell and cleat infillings cross cutting veins and thin laminae parallel to the organic matter and detrital clay bands a late syngenetic low temperature hydrothermal fluid injection process is suggested for formation of the feldspar veins the origin of the fluid is uncertain but is most likely associated with contemporaneous volcanic activity

mineralogy and organic petrology of oil shales in the sangkarewang formation ombilin basin west sumatra indonesia abstract the ombilin basin is filled by late eocene to early oligocene marginal fan deposits brani formation and lacustrine shales sangkarewang formation unconformably overlain by a late oligocene to early miocene fluvial sequence sawahlunto and sawahtambang formations and capped by an early to mid miocene marine sequence ombilin formation significant oil shale deposits occur in the sangkarewang formation intercalated with thin laminated greenish grey calcareous sandstones x ray diffraction shows that the sediments consist mainly of quartz feldspar carbonates and a range of clay minerals together in some cases with minor proportions of sulphides evaporites and zeolites feldspar and non kaolinite clay minerals decrease up the sequence relative to kaolinite suggesting a changing sediment source as the basin was filled calcite thought to be mainly of authigenic origin is also more abundant in the middle and upper parts of the sequence the organic matter in the oil shales of the sequence is dominated by liptinite macerals particularly alginite mainly lamalginite and sporinite cutinite also occurs in some samples along with resinite and traces of bituminite the dominance of lamalginite in the liptinite components suggests that the material can be described as a lamosite samples from the sangkarewang formation have vitrinite reflectance values ranging between 0 37 and 0 55 these are markedly lower than the vitrinite reflectance for coal from the overlying sawahlunto formation 0 68 possibly due to suppression associated with the abundant liptinite in the oil shales fischer assay data on outcrop samples indicate that the oil yield is related to the organic carbon content correlations with xrd data show that with one exception the oil yield and organic carbon can also be correlated directly to the abundance of carbonate calcite and inversely to the abundance of quartz plus feldspar this suggests that the abundance of algal material in the lake sediments was preferentially associated with carbonate deposition high yields of oil are noted in some samples as a percentage of the organic carbon content this may indicate that partial generation of hydrocarbons from the material has already taken place in association with thermal maturation of the sangkarewang succession

organic petrographical mineralogical and geochemical features of the achlada and mavropigi lignite deposits nw macedonia greece abstract the achlada and mavropigi lignite deposits in northern greece provide the main coal source for the next generation of greek power plants a comparative characterization of these two lignite deposits is presented covering the coal rank and the features of the maceral components based on detailed coal petrography and the mineralogical and geochemical features of the coals and their ashes based on xrf and xrd analyses the data are used to interpret the palaeoenvironments of the lignite beds as well as factors that may affect their burnout behavior both deposits have a lignite c rank the mavropigi lignite is mainly a matrix lignite lithotype whereas the achlada deposit consists both of matrix and xylite rich lithotypes the achlada lignite was formed in a fluviatile environment mainly in the abandoned channels of a meandering river system during flooding periods hence it is enriched in inorganic matter with ash values 30 wt the mavropigi lignite formed in a reed marsh environment under limno telmatic conditions and displays ash values the inorganic matter of the two deposits is different in composition due to the contrasting environments and these differences should be taken into account in optimizing their utilization for power production a preliminary assessment indicates that the achlada lignite may have more favorable slagging and fouling properties than the mavropigi lignite although experimental studies are required for more solid conclusions to be reached

enrichment of bi be mo cd pb nb ga rees and y in the permian coals of the huainan coalfield anhui china discussion abstract the paper enrichment of bi be mo cd pb nb ga rees and y in the permian coals of the huainan coalfield anhui china by munir et al 2018 provides new data on the geochemical compositions of the late paleozoic coals from five different mines in the huainan coalfield china as well as proximate analyses vitrinite reflectance measurements maceral contents and mineralogical constituents a critical examination however suggests that a large proportion of the reported data are questionable and also that references cited at a number of points are either improper or incomplete

use of mineralogical analysis in geotechnical assessment of rock strata for coal mining abstract the fundamental geotechnical properties of sedimentary rocks from the coal bearing sydney basin of new south wales australia including density porosity water absorption and moisture content as well as compressive strength have been related to the mineralogy of the materials as determined by quantitative x ray diffraction of powdered rock samples and processing by the rietveld based siroquant technique the results show for example that the overall proportions of clay minerals in the rocks as well as the types of clay minerals present affect properties such as water absorption and moisture content the presence of clay minerals also adds to the dry strength of silica cemented quartz sandstones however the strength of finer grained mudrocks is inversely related to the total percentage of clay minerals correlations have been established between the deterioration or slaking behaviour of mudrocks in water and their clay mineral content based on either simple immersion tests or on more sophisticated slake durability index determinations these relationships may be of significance in understanding the longer term behaviour of rock strata when exposed in different types of mining operations the propensity of different rocks to ignite methane in underground mines by frictional effects has also been shown to depend on the mineralogy of the rock materials whether determined by point counting of thin sections or by rietveld based xrd analysis abundant quartz feldspar and rock fragments in sandstones for example increase the likelihood of frictional ignitions whereas clay minerals and especially carbonates in the rock reduce the frictional ignition potential pyrite in the rocks if present also increases the ignition risk pyrite undergoes exothermic oxidation at high temperatures whereas other minerals respond by simple heating due to rock on rock or pick on rock friction processes