Coal mine workers' pneumoconiosis

 The fibrogenic and cytotoxic potential of coal mine dust is independent of the amount of quartz and other inorganic parameters. Results of coal petrographical and organic geochemical investigations of coals and coal mine dust from the Ruhr and Ibbenbüren Region of Germany demonstrate variations of organic dust amount possibly influencing these noxious properties. Coal mine dust of high rank coals is characterized by a pronounced fibrogenic risk. This risk, independent of the quantity of quartz, is probably based on shape variations of different coal macerals. With increasing coalification of the corresponding seam, the vitrinite is enriched in its dust; however, lower concentrations have been determined for inertinite. Vitrinite shows constant shapes and sizes independent of the rank of coal. Inertinite particles with elongated to fibrous shapes tend to larger sizes with increasing coalification. Strikingly, coal mine dust from miners' lungs with high degrees of coal mine workers' pneumoconiosis (CWP) is enriched in inertinite. In contrast, high cytotoxicities in cell tests are known for coal mine dust from low coalified coals. High concentrations of phenolic compounds can be extracted by dichloromethane from low coalified coal mine dust. These compounds, which are characterized by a high water solubility and therefore high bioavailability, explain the high cytotoxicities of coal mine dust. Contamination of dust by diesel emissions in the coal mine can act as additionally supporting parameters for extended cytotoxicities. Received: 18 August 1995 · Accepted: 15 October 1995     

Chemical composition of macerals in bituminous coals of the Gunnedah Basin, Australia, using electron microprobe analysis techniques

The chemical composition of the organic matter in the principal macerals of high-volatile bituminous coals from the Gunnedah Basin, New South Wales (Rv_max of telocollinite between 0.6 and 1.1%) has been evaluated from polished section specimens using an electron microprobe technique. Highest proportions of carbon occur in the inertinite macerals, especially fusinite and secretinite (formerly resino-sclerotinite), as well as in sporinite; lowest proportions of carbon occur in the different macerals of the vitrinite group. Oxygen shows the reverse trend, being most abundant in vitrinite and least abundant in the inertinite components, whereas sulphur is lowest in the inertinites and highest in the liptinite (mainly sporinite) present. Evaluations of maceral composition, using the carbon content of telocollinite as a rank indicator, show that carbon is more abundant in both sporinite and semifusinite, relative to vitrinite, in low-rank high-volatile bituminous coals. The difference decreases with increasing rank, and the proportion of carbon in telocollinite becomes essentially the same as that in sporinite and semifusinite at carbon contents of about 89 and 91%, respectively. The carbon content of fusinite and secretinite, on the other hand, does not seem to vary appreciably with rank advance. No significant difference in composition occurs in the rank range studied between the three vitrinite varieties present, desmocollinite, telocollinite and a more highly reflecting telocollinite resembling pseudovitrinite. No evidence was found to indicate a higher hydrogen content, relative to telocollinite, for the vitrinite matrix of desmocollinite.     

煤中氯赋存形态的试验研究

采用艾氏卡熔样—硫氰酸钾滴定法,对我国41个煤中氯的含量进行测定,并研究了煤中氯含量与挥发分、固定碳、灰分以及碱金属的关系。结果表明,我国煤中氯含量普遍较低,一般为0.1%~0.2%;煤中氯含量与煤的煤化程度有明显关系,煤的变质程度越高,煤中氯的含量越少。煤中氯含量与煤中水分和氟的含量无关。随着煤中碱金属含量的增加,煤中氯含量呈下降趋势,煤中氯与碱金属(Na,K,Ca,Mg)等存在负相关性。煤中氯主要以有机形式存在。      

Petro-chemical investigation of some perhydrous Indian coals

An attempt has been made to study the petro-chemical characteristics of some high sulphur sub-bituminous coal samples from Makum coalfield, Assam, India. The proximate and ultimate analyes were carried out and forms of sulphur were determined and their relationships with the Maceral constituents (vitrinite, liptinite, and inertinite) were investigated. The macerals (vitrinite+liptinite+inertinite) have significant relationships (R²>0.500) with volatile matter and carbon, whereas weak correlations were seen with rest of the physico-chemical characteristics of the coals. The study reveals that these coals are rich in vitrinites and sulphur and are aromatic in nature. These coals have good hydrocarbon potential.     

Comparison of the Eastern and Western Kentucky coal fields (Pennsylvanian), USA—why are coal distribution patterns and sulfur contents so different in these coal fields?

More than 130 Mt of Pennsylvanian coal is produced annually from two coal fields in Kentucky. The Western Kentucky Coal Field occurs in part of the Illinois Basin, an intercratonic basin, and the Eastern Kentucky Coal Field occurs in the Central Appalachian Basin, a foreland basin. The basins are only separated by 140 km, but mined western Kentucky coal beds exhibit significantly higher sulfur values than eastern Kentucky coals. Higher-sulfur coal beds in western Kentucky have generally been inferred to be caused by more marine influences than for eastern Kentucky coals.Comparison of strata in the two coal fields shows that more strata and more coal beds accumulated in the Eastern than Western Kentucky Coal Field in the Early and Middle Pennsylvanian, inferred to represent greater generation of tectonic accommodation in the foreland basin. Eastern Kentucky coal beds exhibit a greater tendency toward splitting and occurring in zones than time-equivalent western Kentucky coal beds, which is also inferred to represent foreland accommodation influences, overprinted by autogenic sedimentation effects. Western Kentucky coal beds exhibit higher sulfur values than their eastern counterparts, but western Kentucky coals occurring in Langsettian through Bolsovian strata can be low in sulfur content. Eastern Kentucky coal beds may increase in sulfur content beneath marine zones, but generally are still lower in sulfur than mined Western Kentucky coal beds, indicating that controls other than purely marine influences must have influenced coal quality.The bulk of production in the Eastern Kentucky Coal Field is from Duckmantian and Bolsovian coal beds, whereas production in the Western Kentucky Coal Field is from Westphalian D coals. Langsettian through Bolsovian paleoclimates in eastern Kentucky were favorable for peat doming, so numerous low-sulfur coals accumulated. These coals tend to occur in zones and are prone to lateral splitting because of foreland tectonic and sedimentation influences. In contrast, Westphalian D coal beds of western Kentucky accumulated during low differential tectonic accommodation, and therefore tend to be widespread and uniform in characteristics, but exhibit higher sulfur values because they accumulated in seasonally drier paleoclimates that were unfavorable for peat doming. Hence, basin analyses indicate that many differences between the mined coals of Kentucky's two coal fields are related to temporal changes in paleoclimate and tectonic accommodation, rather than solely being a function of marine influences.     

The geology, petrology, palynology and geochemistry of Permian coal basins in Tanzania: 2. Songwe-Kiwira Coalfield

This study provides coal quality, petrological, palynological and geochemical (Rock Eval) data on Permian coal seams and associated shales and mudstones of the Karoo Supergroup of the Songwe-Kiwira Coalfield, Tanzania. The coal seams, which have a cumulative thickness of 6.80 m, occur in the shale–coal–sandstone facies of the Mchuchuma Formation of Artinskian to Kungurian(?) age.Coal quality data (calorific values, volatile matter contents) and vitrinite reflectances indicate high volatile C bituminous to high volatile A bituminous coals, having relatively high ash yields (22–49 wt.%) and highly variable sulphur contents (0.17–9.2 wt.%). They could be used to fuel small-scale power generation units thereby providing electricity to nearby towns and villages. Also, the coals could be used as a substitute for wood, which is becoming increasingly scarce. In rural Tanzania, charcoal is still the main energy source for cooking, and wood is used extensively in brick kilns and for making roofing tiles.Petrological analysis indicated that the coals are dominated by dull to banded dull lithotypes, with seams at the base of the Mchuchuma Formation enriched in inertinite macerals (up to 83 vol.%), whereas up-section vitrinite contents increase. Palynological analyses indicated that the assemblage in the lower Mchuchuma Formation (Scheuringipollenites assemblage) is dominated by trilete spores, whereas in the remainder of the section, non-taeniate disaccates dominate (Scheuringipollenites–Protohaploxypinus assemblage). Facies critical macerals suggest for most seams a marsh/wet forest swamp depositional setting, which is consistent with the palynological data.Rock Eval analyses indicate type II/III kerogen, with Tmax (°C) values ranging from 426 to 440, corresponding to the early stage of hydrocarbon generation. Thermal Alteration Indices (2 to 2+) and vitrinite reflectance levels (0.60–0.83 Ro (%) support the Rock Eval maturity assessment, and despite the predominance of terrestrial-derived organic matter, there is evidence of oil generation and expulsion in the form of cavity and fracture filling exsudatinite.     

Mineral matter and trace elements in coals of the Gunnedah Basin, New South Wales, Australia

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 ( ™), 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.     

Quality of selected coal seams from Indiana: implications for carbonization

The chemical properties of two high-volatile bituminous coals, the Danville Coal Member of the Dugger Formation and the Lower Block Coal Member of the Brazil Formation from southern Indiana, were compared to understand the differences in their coking behavior. It was determined that of the two, the Lower Block has better characteristics for coking. Observed factors that contribute to the differences in the coking behavior of the coals include carbon content, organic sulfur content, and oxygen/carbon (O/C) ratios. The Lower Block coal has greater carbon content than the Danville coal, leading to a lower O/C ratio, which is more favorable for coking. Organic sulfur content is higher in the Lower Block coal, and a strong correlation was found between organic sulfur and plasticity. The majority of the data for both seams plot in the Type III zone on a van Krevelen diagram, and several samples from the Lower Block coal plot into the Type II zone, suggesting a perhydrous character for those samples. This divergence in properties between the Lower Block and Danville coals may account for the superior coking behavior of the Lower Block coal.     

Further examination of the ragged edge of the Herrin Coal Bed, Webster County, Western Kentucky Coal Field

The Herrin (Western Kentucky No. 11) coal bed in the Dixon 7 1/2 min quadrangle, Webster County, Kentucky, displays another manifestation of the thinning margin of the coal bed. Previous studies in adjacent Hopkins County have demonstrated that the coal is brecciated as the margin is approached. The brecciated coal is not always thin; 1.5 m of brecciated, inertinite-rich coal was previously described to the southeast of the present study area. In general, the brecciated coals are considerably thinner than the 1.5–2-m-thick, “normal” Herrin coal. Both cores studied are thin (22.6 and 33 cm) and display petrographic characteristics different from thicker Herrin coals. The cores described in the present study show some signs of brecciation; in certain cases, the fragmented macerals are cemented by exsudatinite. Multiple generations of pyrite mineralization were noted in one core, with total sulfur exceeding 13% in the upper 8.48 cm lithotype.Overall, the cores investigated in this study, along with examples from previous studies, illustrate the progression of the Herrin coal from its absence, either through nondeposition or erosion, through thin, brecciated coals, to mineable coals. No other economic coal in western Kentucky shows as many examples of the depositional edge as does the Herrin. All of the examples studied are from cores, emphasizing the need to study more than just the thick, mineable coals if the total extent of the coal body is to be understood.     

An expert system based on hybrid ICA-ANN technique to estimate macerals contents of Indian coals

Coal, as an initial source of energy, requires a detailed investigation in terms of ultimate analysis, proximate analysis, and its biological constituents (macerals). The rank and calorific value of each type of coal are managed by the mentioned properties. In contrast to ultimate and proximate analyses, determining the macerals in coal requires sophisticated microscopic instrumentation and expertise. This study emphasizes the estimation of the concentration of macerals of Indian coals based on a hybrid imperialism competitive algorithm (ICA)–artificial neural network (ANN). Here, ICA is utilized to adjust the weight and bias of ANNs for enhancing their performance capacity. For comparison purposes, a pre-developed ANN model is also proposed. Checking the performance prediction of the developed models is performed through several performance indices, i.e., coefficient of determination (R ²), root mean square error and variance account for. The obtained results revealed higher accuracy of the proposed hybrid ICA-ANN model in estimating macerals contents of Indian coals compared to the pre-developed ANN technique. Results of the developed ANN model based on R ² values of training datasets were obtained as 0.961, 0.955, and 0.961 for predicting vitrinite, liptinite, and inertinite, respectively, whereas these values were achieved as 0.948, 0.947, and 0.957, respectively, for testing datasets. Similarly, R ² values of 0.988, 0.983, and 0.991 for training datasets and 0.989, 0.982, and 0.985 for testing datasets were obtained from developed ICA-ANN model.     

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.     

不同沉积环境成因煤显微组分的有机硫分布

运用扫描电镜能谱微区测试对不同沉积环境成因煤的有机显微组分进行有机硫含量的系统测定，结果表明在不同类型的煤中某一类显微组分的有机硫含量存在明显差异；同一煤中不同亚显微组分的有机硫含量也不同。综合分析发现煤显微组分有机硫含量主要受聚煤环境、组分凝胶化程度、氧化程度的影响，而聚煤环境为主导影响因素。     

Electron-probe microanalysis of light elements in coal and other kerogen

Recent advances in electron microprobe technology including development of layered synthetic microstructures, more stable electronics and better matrix-correction programs facilitated routine microanalysis of the light elements in coal. Utilizing an appropriately equipped electron micro-probe with suitable standards, it is now possible to analyze directly the light elements (C, O and N, if abundant) in coal macerals and other kerogen. The analytical results are both accurate compared to ASTM methods and highly precise, and provide an opportunity to access the variation in coal chemistry at the micrometre scale. Our experiments show that analyses using a 10 kV accelerating voltage and 10 nA beam current yield the most reliable data and result in minimum sample damage and contamination. High sample counts were obtained for C, O and N using a bi-elemental nickel-carbon pseudo-crystal (2d = 9.5 nm) as an analyzing crystal.Vitrinite isolated from anthracite rank coal proves the best carbon standard and is more desirable than graphite which has higher porosity, whereas lower rank vitrinite is too heterogeneous to use routinely as a standard. Other standards utilized were magnesite for oxygen and BN for nitrogen. No significant carbon, oxygen or nitrogen X-ray peak shifts or peak-shape changes occur between standards and the kerogen analyzed. Counting rates for carbon and oxygen were found to be constant over a range of beam sizes and currents for counting times up to 160 s. Probe-determined carbon and oxygen contents agree closely with those reported from ASTM analyses. Nitrogen analyses compare poorly to ASTM values which probably is in response to overlap between the nitrogen K α peak with the carbon K-adsorption edge and the overall low nitrogen content of most of our samples.Our results show that the electron microprobe technique provides accurate compositional data for both minor and major elements in coal without the necessity and inherent problems associated with mechanically isolating macerals. Studies to date have demonstrated the level of compositional variability within and between macerals in suites of Canadian coals.     

枣庄煤田太原组煤中微量元素地球化学特征

采用中子活化法测定了山东枣庄煤田晚古生代太原组高硫煤层中的微量元素质量分数 ,用数理统计方法取得了高硫煤中微量元素的浓度分布范围、平均值和变异系数 ,用逐步聚类分析法和相关分析法分析了微量元素的共生组合关系 ,并用扫描电镜 -能谱分析了不同煤岩组分的微量元素浓度 ,在此基础上结合形态硫分析结果和沉积相分析结果 ,讨论了高硫煤中微量元素的富集因素、聚集机理和成因背景 ,指出受海水影响的沼泽沉积环境不但对煤中形态硫的分布和含量有控制作用 ,同时对煤中微量元素的浓度和共生组合特点也有影响。太原组高硫煤中的微量元素按其成因可分成两组 ,一组是陆源碎屑富集型 ,其含量直接与煤中灰分产率呈正相关关系 ;另一组为盆地内部沉积 -生物作用富集型元素 ,海水的入侵和盆地介质的停滞还原条件和陆源碎屑物质输入量的减少最有利于沉积 -生物作用型元素的富集 ,并以有害元素 Cu、As、 U、 Pb、 Mo、 Sr和 Co的富集为特征。煤中黄铁矿及其他硫化物是许多有害元素的重要载体 ,充分凝胶化的富氢镜质体比其他组分承载和吸附有更多的有害元素。深入研究不同煤层的有害元素的有机亲和性有利于指导煤的合理利用和采用有效的有害元素的去除措施 ,以利于煤的有效和洁净利用     

瓦窑堡煤系有机岩石学特征及煤成烃潜力研究

瓦窑堡煤系是我国重要的含煤岩系之一,陆相生油的观点最早可能源于瓦窑堡煤系含油性特征。通过对瓦窑堡煤系煤和暗色泥岩有机质的显微岩石学和宏观煤岩学特征的分析,提出了瓦窑堡煤系煤主要形成于深覆水森林泥炭沼泽相,类脂组含量高,且镜质组的主要类型为富氢的基质镜质体,有机地球化学结果表明瓦窑堡煤系煤具有Ⅱ型有机质的特征,处于低熟-成熟阶段,热模拟实验证明其具有良好的油气生成潜力。但由于瓦窑堡煤系规模小,煤层厚度薄,煤系泥岩有机质类型偏差,且煤中主要生油显微组分尚末进入大量生油期,因此难以形成油藏。     

鄂尔多斯盆地延安组煤有机岩石学研究

鄂尔多斯盆地侏罗纪延安组煤系地层可否成为该盆地另一套油源岩的问题,历来存有争议。系统的煤岩和有机岩石学分析表明:煤中倾油性的壳质组分含量低,基质镜质体的类型也不利于生油,因此,延安组煤系有机质不大可能形成具有工业价值的煤成油藏     

Clausthalite in coal

A lead selenide mineral, tentatively identified as clausthalite (PbSe) based on optical microscopy, scanning electron microscopy with energy-dispersive X-ray (EDAX), electron microprobe, and scanning proton microprobe (SPM), has been described in a number of coals. While clausthalite has been mentioned as a possible source of Se in coal, it is present in such small quantities and sizes, that the mineral identification has not been absolutely confirmed. The mineral specimens examined in this study would contribute, not only to the Pb and Se concentrations in the coal, but also, in at least one case, to Hg concentrations.     

The petrology of greek brown coals

Results are given in the petrography of Greek coals collected from most of the major coal-bearing basins in Greece.Rank was determined by measuring reflectances on the maceral varieties eu-ulminite A and eu-ulminite B and on the maceral textinite. Reflectances obtained from these components indicate a coalification stage of brown coal for all samples. Within this group of samples there is, however, a fairly wide scatter of reflectance values indicating for some of them the transition zone from peat to brown coal and for others a coalification stage close to the transition into bituminous coals. Reflectances obtained from eu-ulminite A and eu-ulminite B were found to correlate well with chemical rank parameters such as volatile matter and calorific value.Composition was determined by maceral analysis. The coals are in general characterized by low amounts of macerals of the inertinite group, low to intermediate amounts of macerals of the liptinite group and high amounts of macerals of the huminite group. Within the latter group densinite, attrinite, eu-ulminite and textinite make up the bulk of the samples.Typical macerals observed in the coals are illustrated by two black and white and three colour plates.Cluster analysis based on maceral distribution, mineral matter and reflectance indicates that the samples studied can be divided into three major groups. The first one is dominated by eu-ulminite and densinite with relatively high reflectances. The second is dominated by attrinite, textinite and texto-ulminite with somewhat lower reflectances. The third is represented by a single sample in which textinite and resinite are the most abundant macerals. This sample also has the lowest reflectance.     

中国陆相源岩显微组分的分类及其岩石学特征

本文通过对中国6个主要油田及15个煤田共三百多块陆相源岩所作的详细有机岩石学研究,提出了以全岩与干酪根为基础的分散有机质分类方案,系统总结了显微组分光性、成因及分布规律,鉴定出了我国陆相源岩中三种新显微组分。此分类不仅适用于低成熟源岩,而且还可用来划分过成熟干酪根的显微组分。     

煤中砷的赋存状态

砷是煤中常见的有害微量元素,由于其丰度较低,定量研究其赋存状态一直很困难。近年来,采用逐级化学提取实验方法对煤中不同赋存状态的砷进行了定量研究,综合分析这些研究可得出以下结论：①煤中砷的赋存状态包括硫化物态砷、有机态砷、砷酸盐态砷、硅酸盐态砷、水溶态和可交换态砷。总体上,硫化物态砷＞有机态砷＞砷酸盐态砷＞硅酸盐态砷＞水溶态和可交换态砷,但在不同的煤样品中,也表现出较大的差异性。②一般而言,煤中大部分砷存在于含砷黄铁矿中,含砷黄铁矿中的砷含量与黄铁矿的成因或类型有关。煤中的砷酸盐态砷主要与铁氧化物和氢氧化物共生;硅酸盐态砷主要进入粘土矿物晶格。③在砷含量较低的煤样品中,有机态砷含量较高,其中在褐煤和低煤级烟煤中,可提取出与腐殖酸和富里酸结合的砷。当前还难以确认有机态砷的化学结构。④贵州特高砷煤中砷的赋存状态较为复杂,在某些样品中与氧结合的有机态砷为主要的赋存状态。