Facies control on the petrographic composition of inertitic coals

The petrography of lignitic, subbituminous and bituminous inertinitic coals (i.e. coals containing > 30 modal percent inertinite on a mineral-matter-free basis) derived from limnic and paralic facies in the Upper Silesian coal basin of Poland was investigated. Paralic coals were observed to contain small amounts of telinite and abundant pyrofusinite compared to limnic coals. The ratio of oxysemifusinite and oxyfusinite to pyrosemifusinite and pyrofusinite is lower in paralic coals as compared to limnic coals. The statistical analysis of the reflectances of the inertinite group macerals and of vitrinite shows that paralic coals are more heterogeneous than limnic coals. This greater degree of heterogeneity may explain the differences in reactivity among coals that otherwise have the same rank and elemental and petrographic composition.     

Organic petrographic investigations of the Kupferschiefer in northern Germany

Results of an organic petrographic study of the Kupferschiefer (Zechstein, Upper Permian) in northern Germany are presented. Because vitrinite occurs only sporadically in this black shale, the random reflectance (R_r) of a relatively high reflecting, vitrinite-like variety of bituminite was measured as a maturity parameter and the problems connected with this procedure were investigated.The main organic component is bituminite, generally with an abundance of more than 90%. Sporomorphs and algae are relatively scarce, inertinite is usually a trace component, and vitrinite is present only in some samples taken close to the coast of the Zechstein sea. Migrabitumen also occurs in small amounts in a few samples. The range of the bituminite reflectance values is often considerable and depends on rank, anisotropy, particle size, porosity, and shearing. Interpretation of the reflectance values is made difficult by differences of up to 0.4% R_r between layers within the Kupferschiefer. Hydrothermal alteration may also be present. The difference between the reflectance of the light and normal varieties of bituminite disappears between 0.9 and 1.2% R_r.Bituminite behaves in a way very similarly to vitrinite during coalification. Their reflectance is identical between 2 and 4% R_r. Below 2% R_r, the reflectance of bituminite is lower than that of vitrinite. Linear regression curves valid up to 4% R_r were calculated for R_max versus R_r and for R_r versus R_max. Taking certain limitations into consideration, bituminite reflectance may be used as a coalification parameter.     

大同煤田接触变质煤的煤岩煤质变化规律

大同煤田石炭-二叠纪煤层中的岩浆岩侵入造就了大量的接触变质煤,降低了煤的利用价值。为了详细探讨岩浆岩体距煤层距离对煤的物理化学性质影响,通过对塔山井田5222巷的辉绿岩岩墙及周围煤层的地质编录、系统采样,及煤样的煤岩学分析、工业分析和元素分析,研究接触变质带的煤岩煤质特征。结果表明：接触变质煤在高温条件下生成各种天然焦微观结构,如镶嵌结构、流动结构、热解碳等;侵入体对煤层的瞬时加热显著提升了热变煤的煤级,镜质体最大反射率由正常煤的0.67%~0.87%增至接触变质煤的0.94%~3.67%;接触变质煤中水分含量和灰分产率显著升高,挥发分产率降低;靠近岩墙的煤样中C含量上升,H、N、O含量下降。综合分析认为,岩墙接触变质作用对煤层的影响范围约4.5 m,即1.25倍岩墙宽度,而严重变质带为1.6 m。研究成果为煤的开采利用评价提供依据。     

Properties of altered coals associated with Carboniferous red beds in the Upper Silesian Coal Basin and their tentative classification

In the Czech and Polish parts of the Upper Silesian Coal Basin, red beds associated with the pre-Neoide tectonic structures are found. The occurrence of these beds is connected with changes in the development of the coal seams, in the macroscopic and microscopic character of coal and with its chemical and technological properties. These changes are due to the thermal and oxidation alteration of coal as a result of geological processes which, up to now, have not been clarified unambiguously. These altered coals were divided into groups according to their chemical and physical properties and vitrinite reflectance using statistical multicomponent methods. Coal samples classified as belonging to one of these groups correspond to a certain type of coal, characterized by a particular grade of thermal and oxidation alteration and petrographical composition.     

Gondwana coals of Bhutan Himalaya - Occurrence,properties and petrographic characteristics

A narrow belt of highly inclined coal-bearing Gondwana strata occurs in the extreme south-eastern part of Bhutan Himalaya. Recently, a systematic survey was undertaken along this coal belt and coals of three areas were analyzed in detail for the evaluation of their physico-chemical properties and petrographic characteristics.The entire region is in the midst of the Great Himalayan orogenic belt, and the whole stratigraphic sequence underwent several diastrophic movements in the geological past. The massive effects of these orogenies is more pronounced in the coal beds of Gondwana sequence, and due to severe crushing and tectonic shearing these coals became powdery and flaky in nature. Significantly, the coals retained their pre-deformational rank exhibiting typical high-volatile, low-rank, bituminous characters, with mild caking propensities. Also these coals are markedly low in sulphur, phosphorus, chlorine and carbonate content like that of Peninsular Gondwana coals.Petrographic studies of these Bhutan coals revealed a close similarity with the eastern Raniganj coals (Upper Permian) of Peninsular India. The tectonic shearing and crushing of the coals are exhibited by the frequent presence of microfolding, microfaulting, and other compressional structures. However, the coals of all the three areas have shown a consistently low order of reflectance values.This typical retention of pre-deformational low-rank bituminous character is a significant feature of Bhutan coals. It shows that massive orogenic movements were only able to physically crush these coals but could not generate the requisite thermal regime to raise the rank of these coals.     

Mineral matter in coals and their reactions during coking

Degradation of coke in the blast furnace is influenced by its inherent mineral matter, the formation of which is itself dependent upon the nature of the coal mineral matter. To date few studies have been made of coke mineralogy and its relationship to the mineralogy of the parent coal. In this study the effect of carbonisation on coal mineral matter has been investigated by a detailed quantitative mineralogical examination of nine cokes and their parent coals. The quantitative analysis was performed on X-ray diffraction patterns of the mineral matter of cokes and coals, using SIROQUANT^™. Coke mineralogy and its composition varied strongly between cokes, more strongly than variations in elemental composition of the ash. The mineral matter in the studied cokes consisted of crystalline mineral phases and also significant levels of amorphous phase (ranging between 44 and 75%). Decomposition of clays such as kaolinite, montmorillonite, illite and chamosite produced the amorphous phase and some of the crystalline mineral phases such as mullite, γ-alumina, spinel, cristobalite and leucite. The type of association of mineral matter in coals had an important role in how the clays decomposed. For example, association of kaolinite with silica-bearing minerals in intimate intermixture favoured formation of mullite over γ-alumina. Akermanite and diopside result from reaction of kaolinite with associated calcium bearing minerals (calcite, dolomite or ankerite). Quartz, fluorapatite and the three polymorphs of TiO₂ (anatase, brookite and rutile) were the coal minerals that were least affected during carbonisation, as they were also found in the cokes, yet even they were affected in some cases.     

Rare-earth mineralization in early Carboniferous coals of the Volga-Ural region

This study presents new ICP spectroscopy data on lanthanide concentrations in early Carboniferous coal deposits in the Volga-Ural region. The results confirmed an overall LREE over HREE enrichment and emphasized the role of carbonate host strata as a major factor that is responsible for REE enrichment and geochemical anomalies. The results of this study were also used to identify the modes of REE occurrences in the organic and inorganic constituents of coal.     

Doppleritization of xylitic coal in the light of petrographic and chemical investigations

The paper presents the results of petrographic and chemical investigations of xylitic coal, xylite and their ash. As is known, a xylitic coal has the function of a lithotype whereas xylites are inclusions brown coals only. All these xylites were arranged according to the increasing degree of doppleritization of xylem in the sequence: common xylite, poorly, moderately and intensely doppleritized varieties, dopplerite coal. The distinctive criteria were their differentiated physical properties, which are also reflected in the variable petrographic and chemical compositions. The petrographic differences result from the replacement of textinite by ulminite and gelinite, while the differentiation of the chemical constitution is due to the increasing carbon content and the increasing number of functional groups that determine the aromatic nature of the internal structure of the coal. Infrared absorption spectroscopy, Raman spectroscopy and chemical analysis of ash have shown that the aromatization of coal and the resulting increase in the degree of order of the structural unit are due to the formation of organomineral compounds in the course of doppleritization. It appears from the investigations that the doppleritization of vegetable matter gives rise to gels that are a mixture of organo-mineral humic compounds. The process of humification leads to the formation of gel made up of humins. It follows then that there are two ways of initial coalification of plant material, both referred to as biochemical gelification.     

淮南朱集井田二叠纪煤中稀土元素地球化学特征

采用电感耦合等离子体-光学发射光谱仪(ICP-OES),系统测定了淮南朱集井田二叠纪3个沉积组11个煤层371个煤样品的稀土元素含量。通过对煤中稀土元素地球化学参数分析,得出以下认识:朱集煤中稀土元素总量位于86×10-6～143×10-6范围内,平均值为112×10-6;稀土元素具有指相意义,靠近物源区的上、下石盒子组煤中稀土元素总量比远离物源区受陆表海影响的山西组煤分别高出38%和25%;上、下石盒子组及山西组煤中稀土元素分配模式总体属于轻稀土富集、重稀土亏损型,轻稀土曲线段呈"右倾"趋势,重稀土曲线段则较为"平坦";样品δEu变化范围为0.52～0.80,平均值为0.59,Eu中度负异常,指示成煤沼泽受陆源碎屑影响较大;样品δCe变化范围为0.93～1.04,平均值为0.99,Ce含量无异常,指示成煤沼泽受海水影响较小;煤中稀土元素总量与煤中灰分呈不太显著的正相关关系(R=0.59),说明成煤过程中陆源碎屑物质所携带的部分稀土元素可能吸附在煤的有机质中。原煤X射线衍射图谱(XRD)和光学煤岩薄片显示煤中矿物以石英和粘土矿物为主,高岭石可能是稀土元素的无机载体。另外,稀土元素与陆源碎屑元素(Si、Al、Ti、Ni、Sc和Se等)相关性较好,而与海相元素(B、Sr和Ca)相关性不明显。     

Petrographic prediction of coking properties for the Curragh coals of Australia

Curragh Queensland Mining Limited, Australia, produces a high quality medium volatile bituminous coking coal from the Orion, Pollux and Castor seams from the upper Permian Rangal Coal Measures. It is one of the lowest ash, prime hard coking coal blends produced in Australia. It is also low in sulfur and produces very strong coke when carbonized alone and in blends. Early attempts to predict coking properties of the coals from petrographic data produced predicted coke stabilities that were significantly lower than those determined from coke tests. There is some question as to how much of the ‘inertinite’ in these and other southern hemisphere coals is truly inert during carbonization and how much is reactive. The current study characterized the Curragh coals in terms of physical, chemical and petrographic characteristics and also involved the production of test oven cokes for characterization and strength testing. As part of the work effort a series of suggested techniques for improving predictions of coke strength from petrographic data were examined and a new and improved technique was developed for the Curragh coals. How broadly the technique can be applied to other coals needs to be determined.     

Weathering at high latitudes on the Carboniferous Old Red Sandstone, petrographic and geotechnical investigations, Jedburgh Abbey Church, Scotland, a case study

Weathering processes and intensity vary according to the predominant environmental conditions as well as the rocks physical and geotechnical properties in a given area. Jedburgh Abbey Church has been taken as a representative historical building constructed from Carboniferous Old Red Sandstone at humid pre-glacial region. The research aims to examine weathering processes and intensity under the environmental conditions of high relative humidity and low temperature, and to determine the output of weathering through an examination of the rocks petrological and geotechnical properties.Thin section study, scanning electron microscope and X-ray fluorescence techniques have been used to examine the rocks petrography and mineralogy on one hand and to determine weathering products on a microscale on the other hand. It is noted that the Carboniferous Old Red Sandstone has a quartz arenite texture with iron oxide and dolomite within its texture, authigenic clays are also detected. Pitting of quartz grains, exfoliation of silica overgrowth and fragmentation of the rocks feldspar can be noted on a microscale resulting in recession of the rocks components cohesion.The geotechnical results indicated variation in the physical nature of the construction rock from inside to outside the church with recession from the former to the latter due to weathering. The great reduction in mortar and the rocks calcium oxide and high content of both sulphur and chlorine from inside to outside the church is a result of weathering and deposition of air pollutants on the stones surface on the outdoor surfaces. Chemical weathering, e.g. salt hydration and chemical alteration of the rocks carbonate content to sulphate and chloride salts is expected to dominate in the study area at such conditions of low temperature and high relative humidity accompanied with air pollutants.     

Influence of petrographical composition on coking behavior of inertinite-rich coals

Medium-rank inertinite-rich coal samples were collected for study from limnic and paralic facies in the Upper Silesian coal basin of Poland. The microlithotypes seem to control the content of the mosaic textures. It also appears that carbominerites favor the formation of pyrolytic carbons. The coke obtained from poorly pyrofusinitized, homogeneous, limnic coal has higher mechanical strength with larger and thicker cell walls, and is less porous than those derived from highly pyrofusinitized, heterogenous paralic ones. The microstructure of the cokes appears to be controlled by different amounts of fibers and coarse mosaics.     

Determination of rank and petrographic composition of Jurassic coals from eastern Surat Basin,Australia

Petrographic analysis and rank determination were carried out on coals from a Jurassic sequence in eastern Surat Basin, Australia. The coals consist mainly of exinite-rich clarite, with desmocollinite as dominant maceral of the vitrinite group. Petrographically there is no significant variation in the composition of the coals. A herbaceous swamp type, free from severe oxidation/ dehydration, appears to have been a dominant depositional environment during the peat accumulation.The coal rank ranges from sub-bituminous B to high-volatile bituminous C/B. Vitrinite reflectance/ depth profile shows a uniform increase in coalification with depth of burial.     

浙江省上石炭统-中二叠统生物地层划分进展

本文划分论述了浙江省上石炭统-中二叠统16条化石带(其中11条为新建化石带),对比研究结果表明它们分布于老虎洞组、黄龙组、船山组、梁山组、栖霞组、孤峰组、龙潭组下部的地层,可分别与滑石板阶、达拉阶、逍遥阶、紫松阶、隆林阶、栖霞阶、祥播阶、茅口阶、冷坞阶等9个阶对比.探讨研究了上石炭统底界、下二叠统底界和中二叠统底界;指出上石炭统未见底,缺失罗苏期的沉积;下二叠统底界位于Sphaeroschwagerina subrotunda带之底,以Sphaeroschwagerina属的始现作为底界的标准;石炭-二叠系界线位于Triticites subcrassulu (竹蜒)带与Sphaeroschwagerina subrotund (竹蜒)带之间;中二叠统的底界位于Orthotichia chekiangensis腕足组合带之底,以Orthotichia chekiangensis的始现作为中二叠统底界的标准.进一步论证了船山组是一个跨越石炭-二叠系界线的岩石地层单位,下部归属上石炭统逍遥阶,中部归属下二叠统紫松阶和上部归属下二叠统隆林阶.     

淮北煤田二叠纪煤中伴生元素的亲和性研究

以淮北煤田二叠纪10、7、3煤层样品为研究对象，采用仪器中子活化法（INNA）测试了煤中42个伴生元素的含量，将其与华北石炭-二叠纪和中国煤中的伴生元素含量、范围进行了对比，并对伴生元素中主量元素含量和灰分的关系、微量元素的共生组合特点以及稀土元素含量与灰分的关系、稀土元素分布模式进行了初步分析。结果表明，对环境有影响的Ba、Co、Cr、Cu、Mo、Th、V、W、Zn、Ti元素在研究区煤中相对富集，Al、Ti、K、Na等元素与灰分有较好的相关性，Ca、Mg、Fe和灰分的相关性较差，稀土元素与灰分正相关且具有相似的分配模式，普遍存在Eu亏损现象，说明煤中伴生元素的主要来源是陆源物质。     

Generation and expulsion of oils from Permian coals of the Sydney Basin,Australia

Organic geochemical and petrological assessment of coals/coaly shales and fine grained sediments, coupled with organic geochemical analyses of oil samples, all from Permo–Triassic sections of the Southern Sydney Basin (Australia), have enabled identification of the source for the widely distributed oil shows and oil seeps in this region. The Permian coals have higher hydrogen indices, higher liptinite contents, and much higher total organic matter extract yields than the fine grained sediments. A variety of source specific parameters obtained from n-alkanes, regular isoprenoids, terpanes, steranes and diasteranes indicate that the oil shows and seeps were generated and expelled predominantly from higher plant derived organic matter deposited in oxic environments. The source and maturity related biomarkers and aromatic hydrocarbon distributions of the oils are similar to those of the coals. The oil-coal relationship also is demonstrated by similarities in the carbon isotopic composition of the total oils, coal extracts, and their individual n-alkanes. Extracts from the Permo–Triassic fine grained sediments, on the other hand, have organic geochemical signatures indicative of mixed terrestrial and prokaryotic organic matter deposited in suboxic environments, which are significantly different from both the oils and coal extracts. The molecular signatures indicating the presence of prokaryotic organic matter in some of the coal extracts and oils may be due to thin sections of possibly calcareous lithologies interbedded within the coal measures. The genetic relationship between the oils and coals provides new evidence for the generation and expulsion of oils from the Permian coals and raises the possibility for commercial oil accumulations in the Permian and Early Triassic sandstones, potentially in the deeper offshore part of the Sydney Basin.     

The thermal decomposition studies of three Polish bituminous coking coals and their blends

The objective of this work was to investigate the thermal decomposition of various bituminous coal blends. Three Polish coals of varying rank (82.7, 86.2 and 88.7 wt.% carbon content) and caking ability (weak, moderate and strong) were collected from the Krupiński, Szczygłowice and Zofiówka mines, respectively. These coals were used to prepare binary and ternary blends. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were used. The weight loss and heat flow during pyrolysis, and storage/loss elastic modulus measured as a function of increasing temperature were related to the caking ability of coals. Parameters determined with the TGA and the DSC methods in the binary and ternary blends were correlated with the proportion of strongly-caking-coal concentration in the blend. The weight loss of coal blends was found to be additive parameter. The DSC thermograms of binary blends were found to be different from those of the ternary blends, which suggests a different course for this blend pyrolysis.     

中国上石炭统上部及下二叠统海相地层中阶的划分

明确而详细地提出了中国上石炭统上部及下二叠统海相年代地层单位的具体框架。将上石炭统上部划分为消遥阶、下场家河阶；下二叠统划分为上杨家河阶、范家河阶、垭口阶及隆林阶。明确了阶的定义、动物群特征、磁性地层特征及其与相关地层的关系。所划分的阶均能与世界标准年代地层进行详细而有依据的对比。