The application of FAMM (Fluorescence Alteration of Multiple Macerals) analyses for evaluating rank of Paraná Basin coals, Brazil

Combining vitrinite reflectance (VR) and fluorescence alteration of multiple macerals (FAMM) analyses provide insights into the chemical nature of vitrinites (i.e., perhydrous vs. orthohydrous vs. subhydrous compositions) in Permian Gondwana coals of the Paraná Basin, Brazil. The FAMM-derived equivalent VR (EqVR) values and relationships with VR can be determined according to calibration curves based largely on Permian Gondwana coals of eastern Australia.The analytical results indicate that vitrinites in the Paraná Basin coals studied generally range from orthohydrous to perhydrous, with interpreted VR suppression ranging up to 0.2% absolute for the most perhydrous case. The EqVR values of the Santa Catarina coals, which range from about 0.85% to 0.95% differ from VR values by about 0.10–0.15% absolute, potentially having significant implications on coal utilization.The causes of vitrinite reflectance suppression in the Paraná Basin coals are as yet poorly understood, but are likely to be related to a combination of factors.     

Normative mineral composition of high-temperature coal ashes from the Sydney basin coalfields,Australia

Chemical differences in the composition of high-temperature coal ashes of major economic seams of the Sydney Basin were studied using a normative analysis. All chemical data were recalculated to normative mineral assemblages consisting of: quartz, kaolinite and illite. Quartz and clay minerals, the principal constituents of mineral matter occurring in coals, account for most of the variations found in the chemical composition of high-temperature coal ashes between seams of various stratigraphic levels and/or geographic locations. Ternary diagrams based on the quantitative relation of quartz, kaolinite and illite were used to demonstrate these differences.     

Petrographic, mineralogy, and geochemistry of coals of Pabedana, Kerman Province, Central Iran

This paper discusses the result of the detailed investigations carried out on the coal characteristics, including coal petrography and its geochemistry of the Pabedana region. A total of 16 samples were collected from four coal seams d2, d4, d5, and d6 of the Pabedana underground mine which is located in the central part of the Central-East Iranian Microcontinent. These samples were reduced to four samples through composite sampling of each seam and were analyzed for their petrographic, mineralogical, and geochemical compositions. Proximate analysis data of the Pabedana coals indicate no major variations in the moisture, ash, volatile matter, and fixed carbon contents in the coals of different seams. Based on sulfur content, the Pabedana coals may be classified as low-sulfur coals. The low-sulfur contents in the Pabedana coal and relatively low proportion of pyritic sulfur suggest a possible fresh water environment during the deposition of the peat of the Pabedana coal. X-ray diffraction and petrographic analyses indicate the presence of pyrite in coal samples. The Pabedana coals have been classified as a high volatile, bituminous coal in accordance with the vitrinite reflectance values (58.75–74.32 %) and other rank parameters (carbon, calorific value, and volatile matter content). The maceral analysis and reflectance study suggest that the coals in all the four seams are of good quality with low maceral matter association. Mineralogical investigations indicate that the inorganic fraction in the Pabedana coal samples is dominated by carbonates; thus, constituting the major inorganic fraction of the coal samples. Illite, kaolinite, muscovite, quartz, feldspar, apatite, and hematite occur as minor or trace phases. The variation in major elements content is relatively narrow between different coal seams. Elements Sc,, Zr, Ga, Ge, La, As, W, Ce, Sb, Nb, Th, Pb, Se, Tl, Bi, Hg, Re, Li, Zn, Mo, and Ba show varying negative correlation with ash yield. These elements possibly have an organic affinity and may be present as primary biological concentrations either with tissues in living condition and/or through sorption and formation of organometallic compounds.     

Trend-surface analysis of structure and thickness of Bulli Seam, Sydney Basin, New South Wales

Methods are presented which permit the analysis of structural and thickness variations of a stratigraphic interval into a number of components and testing of the components for relationship between structure and thickness. The methods are tested first in the axial region of the South Bulli Syncline area where the Bulli Seam is known to be thicker. Maps of the residual values from the structural and thickness first-degree trends are similar and there is a significant inverse relationship between the residuals. Data from the area where the Bulli Seam occurs also give seam structural and thickness residuals which have a significant inverse relationship. Local exceptions to this relationship are present but in most instances are due to laccolithic doming or changes in lithology of the Bulli Seam. A number of the trend components of structural and thickness variation also show an inverse relationship. It is postulated that most of the present structures defined at the Bulli Seam horizon were active during deposition of the Bulli Seam, and within the limit of the conditions suitable for peat accumulation, controlled thickness of the Bulli Seam. Thickness changes in overlying units suggest that a major part of the warping of the Bulli Seam horizon had occurred by the end of the Triassic Period.     

首批煤炭国家规划矿区煤田地质特征综述

首批煤炭国家规划矿区位于华北赋煤区鄂尔多斯盆地内,主要可采煤层多达10层,分别位于太原组、山西组和延安组。煤质以焦煤和无烟煤为主,其中太原组、山西组煤层具有横向变化小、垂向呈周期性变化的规律;而延安组横向变化较大,聚煤中心具有明显的由南向北迁移现象。受左旋剪切挤压作用,形成了一系列大型北北东向复式褶皱与断层,根据构造复杂程度,确认9个石炭—二叠纪煤田矿区和5个侏罗纪煤田矿区属简单类型。分析首批煤炭国家规划矿区内的控煤构造、矿床水文地质类型、充水因素以及煤层顶底板岩性特征,认为绝大部分矿区煤层稳定、构造和开采技术条件简单。     

Facies analysis of coal seams from the Cracow Sandstone Series of the Upper Silesia Coal Basin, Poland

The main purpose of this study was to recognise the variability of petrographical structure of two coal seams occurring in the Cracow Sandstone Series (Upper Carboniferous/Pennsylvanian, Upper Westphalian), being exploited in the Siersza mine. This mine is located in the eastern part of the Upper Silesia Coal Basin (USCB). The chemical analyses and petrographical features allow the inclusion of these coals to the group of hard brown coals belonging to subbituminous class.Two coal seams (207 and 209/210) of a considerable thickness (7.44 and 6.54 m, respectively), representative of the Cracow Sandstone Series (CSS), were chosen for the petrographic studies. Dominant macroscopic constituents of both seams are banded bright coal and banded coal.The coal seams were sampled in 284 intervals using a channel profile sampling strategy. The microscopical examinations revealed the majority of macerals from the vitrinite group (55%), followed by inertinite (21%), liptinite (11%), and mineral matter (13%). Low values of the vitrinite reflectance (R_o=0.46%) confirm very low coalification of the coal in both seams. Facies analysis indicates that in the course of a mire development, in which the studied coal seams originated, wet forest swamp conditions dominated characterized by a high degree of flooding and gelification as well as by a prevalence of arborescent plants. In such conditions, lithotypes with a large content of bright coal were mainly formed. Petrographic and facies data point to the rheotrophic character of these peatbogs. Frequent changes of the conditions in the peatbog, as it is shown by the variability of petrographic structure of the studied profiles, as well as by lateral changes of the phytogenic sedimentary environment within the coal seams, indicate a strong influence of a river channel on the adjoining peatbogs. An accretion of clastic sediments within the wide river channel belts was balanced mainly by the peatbog growth on the areas outside channels. Frequency and rate of avulsion of the river channels influenced the size, continuity and variability of the peatbogs.     

法国洛林煤田煤质特征与围岩的关系

从法国洛林煤田大量的煤质资料中,选取三个例子来讨论煤层煤质特征与围岩的关系。相对于泥质顶板的煤层来说,砂质顶板的煤层往往煤质变差,表现为具有较低的挥发分产率、较差的结焦性、较高的碳含量、较低的氢含量和较高的镜质组反射率。其原因是砂质顶板的煤层在成煤时期的还原程度较低,丝质组含量较高,其中的镜质组也受到氧化作用而使反射率增高。      

Petrologic and geochemical characteristics of Seam 9-3 and Seam 2, Xingtai Coalfield, Northern China

Six samples of Carboniferous (Mississippian–Pennsylvanian) coal (Seam 9-3) and 11 samples of Permian coal (Seam 2) from the Xingtai Coalfield were studied by petrological and organic geochemical methods. Both seams show different petrological and geochemical compositions. In Seam 9-3 of the Carboniferous age, the predominant maceral is vitrinite (83%) whereas in Seam 2 of Permian age, inertinite predominates (45%). “Barkinite” was found with an average content 1% only in Seam 2. Sixty-four different aromatic compounds were identified by gas chromatography (GC)/mass spectrometry (MS) analysis of solvent extracts (Extr) of both seams. Abundant polyaromatic sulfur hydrocarbons (PASH) were determined in coal samples from Seam 9-3, while they are very low in samples from Seam 2. 1,2,5-Trimethylnaphthalene and 1,2,5,6-tetramethylnaphthalene contents are much higher in Seam 2, while 2-methylfluorene contents are higher in Seam 9-3. Cadalene was found in Seam 2 with a high content of 94 mg/kg coal but was not detected in samples from Seam 9-3. This might indicate a different floral contribution to the sedimentary organic matter. All petrologic and geochemical results indicate that Seam 2 formed in a more oxidized environment compared with Seam 9-3.     

实验变形煤结构的13C NMR特征及其构造地质意义

通过４件煤的高温高压实验样品及２件原始样品的＾１３Ｃ固体核磁共振研究,揭示了变形煤结构演化的微观机理及其与镜质组反射率光性变异的内在联系,阐明了不同应变环境中应力作用的差别在一定程度上控制了碳结构的演化,而镜质组反射率的差别正是煤结构差异的外在反映,因此,煤镜质组反射率光性组构真实地记录了煤变形历史中应力作用及应变环境特征,是煤田构造研究中极为重要的应变标志之一。     

The Late Triassic Callide Coal Measures, Queensland, Australia: Coal petrology and depositional environment

The Late Triassic (Carnian-Rhaetian) Callide Coal Measures are preserved in a partly fault-bounded basin remnant in east-central Queensland, Australia. The sequence comprises up to 150 m of interbedded clastic sedimentary rocks and at least four major coal seams, including one coal body up to 23 m thick. The sequence was deposited initially in high-gradient alluvial fan systems which gave way through time to sandy, low-sinuosity rivers. The restricted, intermontane and entirely alluvial nature of sediment accumulation is here considered to have influence the petrographic characteristics of Callide coals, and their external geometry.The main coal seam from the Callide Measures shows variation in the predominance of some macerals, indicating successions of environmental changes. The application of transmission electron microscopy (TEM) to the study of the Callide coal has enabled a better understanding of the nature and origin of some of the less understood macerals such as micrinite and vitrinite B. Two forms of vitrinite have been observed, each with a distinct reflectance range. The wood-sourced vitrinite A displays an average reflectance of 0.56%, implying a higher rank than the 0.49% Ro total vitrinite reflectance recorded in previous publications. Vitrinite B and A together represent the most commonly occurring macerals in the Callide coal samples of the present study. The lower-reflecting vitrinite B which forms bands, often several hundred μm in thickness, in TEM shows sub-micron electron transparent laminae of lipid-rich material alternating with a more conventional vitrinite material. The vitrinite B is interpreted to represent accumulations of leaves.The Callide coal has entered the oil window, and oil has been generated from some exinite, cutinite, and resinite, as evident from change in fluorescence and the presence of exsudatinite in cell cavities and cleats. Vitrinite B is seen under the microscope to also be generating oil. Micrinite, the origin of which has been much debated, occurs in selected horizons only, as lenticular bodies suggesting cell filling or filling of spaces between laminations in vitrinite B. TEM shows micrinite to consist predominantly of sub-micron pyrite and possibly other mineral particles adsorbed on humic acids.     

Petrography and geochemistry of Carboniferous coal seams in the Donets Basin (Ukraine): implications for paleoecology

The Carboniferous succession in the Donets Basin hosts about 130 seams, each with a thickness over 0.45 m. Nine economically important seams from the (south)western Donets Basin are studied using organic petrographical, inorganic geochemical, and organic geochemical techniques. The main aim of the study is the reconstruction of peat facies of Serpukhovian (Mississippian) and Moscovian (Middle Pennsylvanian) coals.Formation of major coal seams commenced during Serpukhovian times. Early Serpukhovian coal accumulated in a relatively narrow shore-zone and is rich in inertinite and liptinite. Very low ash yields, low to moderate sulphur contents, and upward increasing inertinite contents suggest coal deposition in raised mires.Moscovian coal has a significantly wider lateral extension and is generally rich in vitrinite. Coal properties vary widely in response to different peat facies. Low-sulphur, low-ash k₇ coal was formed in a raised mire or in a low-lying mire without detrital input. l₁ and l₃ seams containing several fluvial partings were formed in low-lying mires. Both seams are more than 2 m thick. Seams m₂ and m₃ contain high-sulphur coal, a consequence of deposition in a peat with marine influence. In contrast, syngenetic sulphur content is low in the m₅^{1 upper} seam, which was formed in a lacustrine setting. The late Moscovian n₁ seam, up to 2.4 m thick, accumulated in a swamp with a vegetation rich in bryophytes and pteridophytes. The properties of the n₁ seam are transitional between those of Serpukhovian and other Moscovian seams. Differences in maceral composition between Serpukhovian and Moscovian coals probably reflect changes in climate and vegetation type.Tuff layers are observed in the l₁, l₃, and m₃ seams. The l₃ and m₃ seams contain abundant authigenic quartz. Trace element contents are high in many seams. As contents are especially high in seams c₁₀², k₇, l₃ and m₃. Ash in the l₃ seam contains up to 8000 ppm As. Co is enriched near the base of several seams. Maxima up to 2400 ppm occur in the ash of the k₇ and l₃ seams. Cd contents in ash are frequently as high as 30 or 40 ppm.     

Economic coalbed methane production in the Canadian Foothills: Solving the puzzle

The producibility of methane at economic rates from thick and very gassy coals in the Canadian Foothills and Mountains remains a major challenge. These structurally deformed, and often sheared, coals are generally characterized by low permeabilities, which is the main limiting factor restricting the flow of gas through natural fractures. A preliminary evaluation of the cleating in the coals and of the jointing in the interburden clastics was carried out in the Elkview mine of SE British Columbia. Field observations were supplemented by microscopic evidence on coal microtextures produced by shearing and their impact on coal permeability. Permeability of the coals tested at simulated in situ stress conditions and parallel to bedding surfaces was highly variable, ranging from 2.09 md in Seam 3, Greenhills mine, to less than 0.001 md in the sheared Seam 10, Elkview mine. This variation may be rationalized based on variations in maceral composition, stress history, degree of shearing, and the mode of deformation of the coal seams in these tectonically complex regions. Shearing gave rise to a variety of complex textures in coal, such as slickensides, shear cones and striated features, small-scale thrusts in the hangingwall, and brittle and ductile microtextures. Furthermore, the coal seams act as aquitards to the flow of water, most likely because of low permeability. Water flow occurs at the contact between coal and interbedded coarser clastics and within the highly fractured and jointed sandstone units. The cone of effective depressurization required for coal gas drainage to occur in the study area is influenced by: (a) the development of a joint system in the more competent clastic beds that would provide the high permeability pathways for water and gas, and (b) the ability of the rocks above the coals to re-pressurize as a result of either surface recharge or water flow both laterally and vertically within the succession. Therefore, multidisciplinary studies of hydrology, coalification history, and structure would help increase our understanding of the mechanisms and timing of cleat development, effect of shearing on coal permeability, and presence of systematic fractures in the non-coaly lithologies.     

The role of sulphide and carbonate minerals in the concentration of chalcophile elements in the bituminous coal seams of a paralic series (Upper Carboniferous) in the Upper Silesian Coal Basin (USCB), Poland

Sulphide and carbonate minerals from nine bituminous coal seams of a Paralic Series were investigated by means of polished-section microscopy, scanning electron microscopy and absorption spectral analyses. In addition to syngenetic accumulations of kaolinite, illite and quartz, diagenetic veinlets of subhedral pyrite and marcasite most often occur in vitrinite clast fissures and in post-tectonic fissures, nests and lenses with fusinite. Epigenetic anhedral and subhedral grains of ankerite, dolomite, siderite and calcite are also frequently found in post-tectonic veins. Pyrite replaced some of the marcasite grains and it dominates in older coal seams in the Flora Beds as compared with the Grodziec Beds. Occasionally there are anhedral and subhedral galena, sphalerite and chalcopyrite grains among coal macerals as well as cerussite among post-tectonic carbonate veins. They all represent the only minerals that are abundant in definite chalcophile elements (Cd, Co, Cu, Ni, Pb, Zn). In addition to the minerals just mentioned, the elements occurred in pyrite and ankerite grains, which contained inclusions of fusinite and other minerals (among others, clay and carbonate minerals in pyrite, pyrite in carbonates). Although there is a low content of minerals accumulating Cd, Co, Cu, Ni, Pb and Zn, the minerals significantly influence the average concentration of elements in the coal seams. In the Grodziec Beds, mineral matter, especially carbonates and sulphides, determines (>50%) the concentration of Cd, Cu, Pb and Zn in coal. The basic part of Cd, Co and Ni in the coal seams of the Grodziec Beds and of Co, Cu, Ni, Pb and Zn in coal seams of the Flora Beds originates from organic matter. These regularities can be important, from an ecological perspective, in stating whether the coals investigated are useful for combustion and in chemical processing.     

A model for the statistical distribution of microlithotypes in coal

Microlithotype composition of a coal sample is often summarized by examining a large number (~500) of subsamples of a grain mount and estimating proportions of vitrite, intermediates, and inertite, where, for samples we have investigated, the proportion of intermediates is generally less than 0.4. This suggests that most subsamples are either greater than 95% vitrinite or greater than 95% inertinite, so that the statistical distribution of vitrinite has most of its weight in its tails. Two distributions which may have this shape are the beta and the logistic normal, and these have been fitted to the microlithotype distribution of some coal samples. Parameters of these fitted distributions are related to the proportion of vitrinite in the sample and thickness of microscopic bands in the coal. For coals in the Sydney Basin, at least, it was found that the parameter relating to band thickness is approximately constant over a coal seam; therefore, fitting one or other of these distributions to such data leads to directly interpretable parameters.     

Possibilities of the utilization of micropetrographic parameters in the scientific classification of bituminous coals

Proposals for new scientific classifications of bituminous coals are based on micropetrographic parameters, i.e. vitrinite reflectance as a criterion of the coalification and maceral composition, presupposed to express the connection between the genetic peculiarities and physical, chemical, and technological properties of the coal mass. In the case of coals with high inertinite contents, however, the utilizability of these parameters meets with difficulties resulting from the subjectivity of determining the different transitional material and from insufficient knowledge of inertinite behaviour at higher temperatures. In the case of the maceral-variable bituminous coals produced in the Ostrava-Karviná Coal Basin, these insufficiencies are not important since it is especially the expression of the variability of the properties of isometamorphic vitrinites, which has decisive effects up-on the course of the thermo-chemical transformations, that is of principal importance to the scientific classification of these coals.In the first approximation, the properties of isometamorphic vitrinites may be expressed by the parameter (H/O)_at, closely connected with fluidity. While the micropetrographic parameters reflect in particular the peculiarities in the chemical structure of the aromatic parts of coal macromolecules, the parameter (H/O)_at expresses the properties of the non-aromatic structures of vitrinite, significantly affecting the course of its thermal degradation. The experimental results show that the value of the parameter (H/O)_at, fluidity and the course of degassing the coal of a lower coalification are independent of the maceral composition and vitrinite reflectance; also that the caking and coking properties of low-rank coals are especially dependent on the parameter (H/O)_at and partially on the micropetrographic parameters. All these facts should be taken into consideration in preparing new scientific classifications of bituminous coals.     

Sub-surface coal seams of Bhupalpalli and Golapalli areas of Godavari valley coalfield and their petrographic characteristics

The research work details the maceral organization of eleven coal seams intersected at a maximum depth of 446.45 m from Bhupalpalli area of the Mulug coal belt, in Warangal district of Godavari valley. Samples for petrographic study have been collected from ten coal seams intersected between 106 m and 299 m depth range from Bore-hole No. 618 which includes, IA and its underlying I, II, Index below II, IIIB, IIIA, III, IVA, IV and Index below IV respectively. However, the coal samples from the bottom most V seam were collected from Bore-hole No. 616 encountered between 445.65 m and 446.45 m. The study has revealed that V seam is marked by vitric type and seam IVA contains coal of fusic nature. The seams I, II, Index below II, IIIB, IIIA and IV, however, are represented by mixed type of coal. Whereas, the seams IA and III have the prevalence of vitric as well as mixed coal types. IA seam has witnessed alternate oxic and anoxic moor condition and also wet moor with intermittent moderate to high flooding. All the other seams have been deposited during alternate oxic and anoxic moor conditions. The coal seams of the study area have shown a wide range of variation in vitrinite reflectance (Ro mean %). The top of III, basal part of IV and the entire Index below IV have recorded high vitrinite reflectance (Ro mean %), which ranges between 0.66-0.67% thus they have reached high volatile bituminous B stage, all the other seams show lower reflectance and therefore have attained high volatile bituminous C rank.     

Petrography and depositional environment of the liddell seam, upper hunter valley, New South Wales

The Liddell Seam occurs in the lower part of the Permian Foybrook Formation of the Sydney Basin, eastern Australia. The seam profile is dominated by banded lithotypes (clarain). Maceral and microlithotype analyses of lithotypes indicate a limited degree of uniformity in their composition. A comparison of whole-seam petrographic analyses with compositions calculated on the basis of the seam lithotype profile and lithotype petrography suggests that the latter method may provide for a rapid assessment of petrographic variation in operating mines.Petrographic analyses form the basis of an interpretation of Liddell peat-swamp facies. The seam contains few clastic layers which are associated with relatively dull coals whose petrography reflects elevated water levels during deposition in the limno-telmatic, reed-moor and open-moor facies. Between these zones the seam profile is dominated by relatively bright coals deposited between periods of inundation, in the telmatic forest-moor and reed-moor zones. The lithotype profile and the high vitrite and clarite content indicate the significant influence of arborescent vegetation, a feature typical of seams deposited in tectonically unstable areas.     

广西合山晚二叠世碳酸盐岩型煤系层序地层分析

广西合山煤田晚二叠世合山组是在浅水碳酸盐台地背景下形成的典型的碳酸盐岩型含煤岩系 ,其沉积环境有滨外陆棚、生物礁、开阔台地、潮坪和泥炭沼泽等。在包括合山组和大隆组在内的整个晚二叠世地层中 ,可以识别出5个层序界面 ,并可根据这些层序界面将区内上二叠统划分为 4个层序。层序 从合山组底面到合山组下段顶部的四 下 煤层底板硅质岩层之底面 ;层序 包括从四 下 煤底板到四 上 煤底板的一套地层 ;层序 为从四 上 煤层底板到二煤层之下铝土质泥岩底板的序列 ;层序 包括从合山组二煤层之下铝土质泥岩底板到大隆组之顶。其中层序 、层序 和层序 厚度在合山煤田范围内变化较大 ,说明受盆地基底沉降作用控制强烈 ,层序 则表现为多次的煤层-石灰岩旋回性 ,并且在合山煤田甚至桂中地区稳定分布 ,说明可能主要受全球海平面变化控制。与滨海平原靠陆一侧的冲积体系的陆源碎屑岩含煤岩系不同 ,陆表海碳酸盐岩型煤系三级层序中的最大海泛带底部以该层序中向上变薄至最薄的一层煤的底面为代表 ,如研究区三 中 煤层底面即为层序 中的最大海泛带底部 ,其下为三级层序中的海侵体系域 ,其上为高位体系域。三级层序中有包含四 上 、三 下 、三 中 、三 上 等煤层为界的 4个四级层序 ,每个四级层序中发育     

Co-carbonization of selected American coals with commercial additives

Because of the short supply of high-quality coking coals in certain areas of the world, many methods of improving the coking characteristics of poorly coking or noncoking coals have been examined as alternatives to importing more expensive, better quality coals. Co-carbonization, or the addition of coal-derived or petroleum-derived materials to the coal charge prior to carbonization, has been used on a commercial basis in the Japanese coking industry. These additives have been used in both solid and liquid form as binders in coal briquettes or as direct additions to the coal blend.In this study three different coal lithotypes were sampled from each of three United States bituminous coal seams: (1) a marginally coking high-volatile B-rank Illinois No. 6 Seam; (2) a highly fluid, good coking quality, high-volatile A-rank Pittsburgh Seam; and (3) a strongly coking low-volatile Blue Creek Seam. Each lithotype sample was carbonized in small-scale (50 g) charges with each of three additives at 0, 2, 5, and 10% additive by weight. The additives included ASP, an asphalt pitch; KRP, a petroleum residue pitch; and SRC, a solvent-refined coal product. The different lithotypes were sampled to examine the effects of coal type as well as rank. A micro-tumbler test was used to give at least a relative coke-strength value for the cokes produced. In addition, all the cokes produced were examined microscopically to determine the effects of co-carbonization on the coke structure.The Illinois No. 6, Pittsburgh, and Blue Creek Seam coals all showed substantial strength increases when co-carbonized with 2, 5, and 10% of each of the three additives, particularly at the 5 and 10% levels. The SRC appears to be the best additive overall for the three ranks of coal, as judged by its ability to combine with the coal to make a higher strength coke. There appear to be no conclusive coke-strength differences among lithotype samples for any of the three coals, probably because of the small scale of the tests and the relatively small differences in inert maceral content among the lithotypes. Five percent by weight of additive appears to be sufficient, if properly blended with the coal charge, to produce higher strength cokes. This is also probably the maximum economically viable level, particularly in the United States coking industry. Two percent is probably the minimum additive level for adequate mixing on a commercial scale.     

Peat-forming environments of Westphalian A coal seams from the Lower Silesian Coal Basin of SW Poland based on petrographic and palynologic data

The petrographic and palynologic compositions of coal seams of the acler formation (Upper Carboniferous, Westphalian A) from northwestern and southeastern part of the Lower Silesian Coal Basin (LSCB) were examined. Coals studied are highly volatile bituminous coal, where R_o ranges from 0.91% to 1.09%. Seam 430 from the northwestern part of the basin contains high vitrinite percentage with rather low inertinite and liptinite contents, while percentage of mineral matter is variable. This petrographic composition is associated either with a predominance of Lycospora in miospore assemblage, or with a miospore assemblage of mixed character. The abundance of Lycospora reflects vegetation composed of the arborescent lycopsids while the mixed miospore assemblage is connected with diverse palaeoplant communities, namely, arborescent lycopsids, calamites and ferns. Seams 409 and 412/413 from the southeastern part of the LSCB are rich in inertinite and liptinite, while the vitrinite content is moderate. Their characteristic feature is the occurrence of a diagnostic crassisporinite (densosporinite). Amount of the mineral components in these coals is very low. Densosporites and related crassicingulate genera are main components of these miospore assemblages and were produced by herbaceous and/or sub-arborescent lycopsids. These petrographic and palynologic features were the basis for distinguishing three maceral–miospore associations: an arborescent lycopsid and mixed associations, occurring in the seam 430 and a herbaceous and/or sub-arborescent lycopsid association which was recorded in seams 409 and 412/413. The first two assemblages are interpreted as having been deposited in a planar rheotrophic mire, whereas the herbaceous and/or sub-arborescent lycopsid association is thought to have developed in an ombrotrophic, domed mire.