Coal Petrology Research Articles

Relations between the organic system and petrology of coal

The organic matter in coal undergoes both aerobic and anaerobic transformation processes. In each case, the redox conditions of development of the organic system are analyzed, and the dependence of coal’s petrographic composition on these conditions is considered. The relation between the oxygen activity, which characterizes the state of the organic system, and the basicity of the water-mineral system is discussed. In terms of the redox conditions, the regional propagation of petrographic types of coal is considered. The possibility of monitoring the oxygen activity in the external organic system is considered.

Characters and thermodynamic study on adsorption of coal with different maceral composition on CO

According to the fact that long-term excess-standard CO in low-to-medium metamorpic grade coal seams has not caused coal spontaneous ignition, this paper has carried out the experimental research on adsorption test of eight typical coal samples with different maceral compositions on CO under different pressures. Comprehensive thermodynamic studies on the corrected adsorption volume were conducted by applying physical chemistry, interface chemistry, coal petrology and coal chemical engineering knowledge. Adsorptivity was evaluated from three aspects, including specific surface area, adsorption capacity on per surface area, and interaction between CO molecule and coal surface. The results show that the adsorption of inertinite is better than that of vitrainite. The change rule in free energy of coal surface under different balance conditions shows that the surface free energy of coal samples with higher vitrinite content is greater than that with higher inertinite content. This explais the main reason why the inertinite has a better adsorption. The isosteric heat of coal samples with higher inertinite content is greater than that with higher vitrinite content and the interaction between CO molecular and coal morphology in coal samples with higher inertinite is greater than that with higher vitrinite.

Coal Petrology - A shifting role from coal utilization to fuel exploration

Coal petrology deals with the study of microscopically recognizable remains of vegetal source matter, termed 'macerals', which for convenience are classified and categorized into three main groups- vitrinite (O2-rich), liptinite (H2-rich) and inertinite (C-rich). Each maceral being specific in its origin, evolution and environmental conditions during genesis has tremendous interpretative value. Vitrinite-rich coals form in anaerobic (wet-reducing) condition, whereas aerobic (dry-oxidative) condition results into the formation of inertinite-rich coals. Macerals of the liptinite group originate in acidic-wet conditions of swamp. Optical properties (reflectance and fluorescence) and quantitative estimations of coal micro-constituents overall reflect the chemical properties and thus help in various interpretations. The studies are convincingly utilized to predict the suitability of coal for specific economic and industrial purposes. Currently, the petrological investigations are being utilized to interpret the potentiality of coal for methane that originates during the time and pressure induced diagenetic and catagenetic stages of coal formation.

Forecast of Geological Gas Hazards for “Three-Soft” Coal Seams in Gliding Structural Areas

Abstract Gas outbursts from “three-soft” coal seams (soft roof, soft floor and soft coal) constitute a very serious problem in the Ludian gliding structure area in western Henan. By means of theories and methods of gas geology, structural geology, coal petrology and rock tests, we have discussed the effect of control of several physical properties of soft roof on gas preservation and proposed a new method of forecasting gas geological hazards under open structural conditions. The result shows that the areas with type III or IV soft roofs are the most dangerous areas where gas outburst most likely can take place. Therefore, countermeasures should be taken in these areas to prevent gas outbursts.

Coal facies evolution of the main minable coal-bed in the Heidaigou Mine, Jungar Coalfield, Inner Mongolia, northern China

The No. 6 Coal-bed from the Heidaigou Mine, Jungar Coalfield, Inner Mongolia is a super-large Ga deposit. The dominant carrier of Ga is boehmite in coal. The study of coal facies may provide genetic enrichment information of Ga and its carrier (boehmite) in the Ga deposit. On the basis of study on coal petrology and mineralogy, it was found that the No. 6 Coal-bed from the Heidaigou Mine of Jungar was enriched in inertinites and the microlitho-types were dominated by clarodurite. The maceral morphological features and association indicate that the coal-bed was formed in a dry sedimentary environment or in a periodic dry sedimentary environment caused by the alternating variations of groundwater level. The optimum conditions for the enrichment of Ga and its particular carrier (boehmite) were dominated by four transitional conditions: (1) the upper delta plain which was the transitional zone between alluvial and lower delta plains, (2) the transitional zone between the dry and wet forest swamps, being slightly apt to the dry one, (3) the transitional tree density between the thick and loose ones, and (4) the low moor that was the transitional zone between two high moors during peat accumulation.

Coal petrology of coal seams from the Leão-Butiá Coalfield, Lower Permian of the Paraná Basin, Brazil — Implications for coal facies interpretations

Abstract In the Leao-Butia Coalfield, Rio Grande do Sul the coal seams occur in the Rio Bonito Formation, Guata Group, Tubarao Supergroup of the Parana Basin, Brazil and are of Permian (Artinskian–Kungurian) age. This study is the first detailed investigation on the coal petrographic characterization of the coal-bearing sequence in relation to the depositional settings of the precursor mires, both in terms of whole seam characterization and in-seam variations. The study is based on the analyses of nine coal seams (I2, CI, L4, L3, L2, L1, S3, S2, S1), which were selected from core of borehole D-193, Leao-Butia and represent the entire coal-bearing sequence. The interpretation of coal facies and depositional environment is based on lithotype, maceral and microlithotype analyses using different facies-critical petrographic indices, which were displayed in coal facies diagrams. The seams are characterized by the predominance of dull lithotypes (dull, banded dull). The dullness of the coal is attributed to relatively high mineral matter, inertinite and liptinite contents. The petrographic composition is dominated by vitrinite (28–70 vol.% mmf) and inertinite (> 30 vol.% mmf) groups. Liptinite contents range from 7 to 30 vol.% (mmf) and mineral matter from 4–30 vol.%. Microlithotypes associations are dominated by vitrite, duroclarite, carbominerite and inertite. It is suggested that the observed vertical variations in petrographic characteristics (lithotypes, microlithotypes, macerals, vitrinite reflectance) were controlled by groundwater level fluctuations in the ancient mires due to different accommodation/peat accumulation rates. Correlation of the borehole strata with the general sequence-stratigraphical setting suggests that the alluvial fan system and the coal-bearing mudstone succession are linked to a late transgressive systems tract of sequence 2. Based on average compositional values obtained from coal facies diagrams, a deposition in a limno-telmatic to limnic coal facies is suggested.

57th Annual Meeting of the International Committee for Coal and Organic Petrology Patras, Greece 18–23 September 2005

57th Annual Meeting of the International Committee for Coal and Organic Petrology Patras, Greece 18–23 September 2005

Matter Composition and Two Stage Evolution of a Liangshan Super High-Sulfur Coal Seam in Kaili, Eastern Guizhou

Super-high sulfur coal resultes in serious coal-derived pollution but might have a particular genesis. Thus, a columnar section of an Early Permian Liangshan Formation coal seam. weight average sulfur content 5.80%, from Kaili, eastern Guizhou, was studied using the methods of coal petrology and geochemistry. The results show that the seam was apparently formed in seawater-effected peat bogs that developed in two distinct stages. During the first stage various layers were formed in a supratidal bog and have a composition characteristic of a bog with a gradually decreasing seawater effect, decreasing water dynamics, and an increasingly reductive environment. Layers in the upper seam formed during a second stage in an intertidal bog. These layers are very high in total and inorganic sulfur, the ratios of organic/inorganic sulfur and V/I drop, they are high in coal ash yield and have a high ash component index, considerable barkinite, oxidized and detrital macerals, have a porphyroclatic micro-structure and are rich in pyrite, all of which indicate the coal-forming environment had higher oxidation potential, strong and roiling water dynamics, and intermittent exposure to a sulfur rich environment.

Effects of Magmatic Intrusion on Mineralogy and Geochemistry of Coals from the Fengfeng−Handan Coalfield, Hebei, China

This paper describes the effects of magmatic intrusions on petrology, mineralogy, and geochemistry of the late Palaeozoic coals from the Fengfeng−Handan coalfield, Hebei, China. The narrowly zoned coals of variable ranks, from high-volatile A bituminous (hvAb), through medium-volatile bituminous (mvb), low-volatile bituminous (lvb), semianthracite (sa), and anthracite (an), to meta-anthracite (ma) in the coalfield, were found to be best explained by magmatic inputs. The minerals derived from magmatic thermal alteration consist of pyrite, calcite, and ankerite, which mainly occur as fracture or vesicle fillings in the thermally altered high-rank coals. The variation in element concentrations with coal ranks (enrichment, depletion, and no variation) and mineralogical affinity were used to classify elements in coals into six groups, groups A−F. Elements in group A (B, F, Cl, Br, and Hg), group B (As, Co, Cu, Ni, and Pb), group C (Sr, Mg, Ca, Mn, and Zn), and Group D (U) were enriched in the altered coals, indicating that the magmatic inputs are the source of these elements. Group A elements are volatile elements that probably came from the hydrothermal solutions, then deposited or were driven off from an organic component in coal by magmatic heat, and then redeposited in the coal. Group B elements mainly distribute in the fracture or vesicle fillings of pyrites. The dominant carriers of group C elements are thermally altered calcite and ankerite. Uranium in group D occurs in organic-bonded and silicate associations. Group E elements, including Sb, Sc, and V, have a depletion trend in the altered coals, and the remaining elements in group F do not clearly vary in the unaltered, slightly altered, or altered coals. The element concentrations independent of coal ranks in groups E and F may suggest that these elements are inherent to the coal.

The diversification of Paleozoic fire systems and fluctuations in atmospheric oxygen concentration

By comparing Silurian through end Permian [approximately 250 million years (Myr)] charcoal abundance with contemporaneous macroecological changes in vegetation and climate we aim to demonstrate that long-term variations in fire occurrence and fire system diversification are related to fluctuations in Late Paleozoic atmospheric oxygen concentration. Charcoal, a proxy for fire, occurs in the fossil record from the Late Silurian (approximately 420 Myr) to the present. Its presence at any interval in the fossil record is already taken to constrain atmospheric oxygen within the range of 13% to 35% (the "fire window"). Herein, we observe that, as predicted, atmospheric oxygen levels rise from approximately 13% in the Late Devonian to approximately 30% in the Late Permian so, too, fires progressively occur in an increasing diversity of ecosystems. Sequentially, data of note include: the occurrence of charcoal in the Late Silurian/Early Devonian, indicating the burning of a diminutive, dominantly rhyniophytoid vegetation; an apparent paucity of charcoal in the Middle to Late Devonian that coincides with a predicted atmospheric oxygen low; and the subsequent diversification of fire systems throughout the remainder of the Late Paleozoic. First, fires become widespread during the Early Mississippian, they then become commonplace in mire systems in the Middle Mississippian; in the Pennsylvanian they are first recorded in upland settings and finally, based on coal petrology, become extremely important in many Permian mire settings. These trends conform well to changes in atmospheric oxygen concentration, as predicted by modeling, and indicate oxygen levels are a significant control on long-term fire occurrence.

Organic petrology of Paleocene Marcelina Formation coals, Paso Diablo mine, western Venezuela: Tectonic controls on coal type

Abstract About 7 Mt of high volatile bituminous coal are produced annually from the four coal zones of the Upper Paleocene Marcelina Formation at the Paso Diablo open-pit mine of western Venezuela. As part of an ongoing coal quality study, we have characterized twenty-two coal channel samples from the mine using organic petrology techniques. Samples also were analyzed for proximate–ultimate parameters, forms of sulfur, free swelling index, ash fusion temperatures, and calorific value. Six of the samples represent incremental benches across the 12–13 m thick No. 4 bed, the stratigraphically lowest mined coal, which is also mined at the 10 km distant Mina Norte open-pit. Organic content of the No. 4 bed indicates an upward increase of woody vegetation and/or greater preservation of organic material throughout the life of the original mire(s). An upward increase in telovitrinite and corresponding decrease in detrovitrinite and inertinite illustrate this trend. In contrast, stratigraphically higher coal groups generally exhibit a ‘dulling upward’ trend. The generally high inertinite content, and low ash yield and sulfur content, suggest that the Paso Diablo coals were deposited in rain-fed raised mires, protected from clastic input and subjected to frequent oxidation and/or moisture stress. However, the two thinnest coal beds (both 0.7 m thick) are each characterized by lower inertinite and higher telovitrinite content relative to the rest of Paso Diablo coal beds, indicative of less well-established raised mire environments prior to drowning. Foreland basin Paleocene coals of western Venezuela, including the Paso Diablo deposit and time-correlative coal deposits of the Tachira and Merida Andes, are characterized by high inertinite and consistently lower ash and sulfur relative to Eocene and younger coals of the area. We interpret these age-delimited coal quality characteristics to be due to water availability as a function of the tectonic control of subsidence rate. It is postulated that slower subsidence rates dominated during the Paleocene while greater foreland basin subsidence rates during the Eocene–Miocene resulted from the loading of nappe thrust sheets as part of the main construction phases of the Andean orogen. South-southeastward advance and emplacement of the Lara nappes during the oblique transpressive collision of the Caribbean and South American tectonic plates in the Paleocene was further removed from the sites of peat deposition, resulting in slower subsidence rates. Slower subsidence in the Paleocene may have favored the growth of raised mires, generating higher inertinite concentrations through more frequent moisture stress. Consistently low ash yield and sulfur content would be due to the protection from clastic input in raised mires, in addition to the leaching of mineral matter by rainfall and the development of acidic conditions preventing fixation of sulfur. In contrast, peat mires of Eocene–Miocene age encountered rapid subsidence due to the proximity of nappe emplacement, resulting in lower inertinite content, higher and more variable sulfur content, and higher ash yield.

Coal petrology and coal seam gas contents of the Walloon Subgroup — Surat Basin, Queensland, Australia

Core, exploration and appraisal drilling over the last four years have targeted the Juandah (upper) and Taroom (lower) Coal Measures of the Middle Jurassic Walloon Subgroup of the Injune Creek Group. These wells have shown that the high-volatile bituminous, perhydrous coals of the Walloon Subgroup have gas contents of between 1 and 14 m3/t and some wells have encountered gas flows at rates of over 30,000 m3/day. This recent work has confirmed the initial supposition that the coals within the Walloon Subgroup contain sufficient quantities of gas to be economically viable as a coal seam gas source. Coal volumes, depth and structure have also been confirmed from the initial work. What has become apparent during this work is the variability in gas content across each of the seams in the Juandah and Taroom Coal Measures and the variability in coal petrographic composition of these two units are controlled by many factors. What has also become apparent is that the Taroom Coal Measures have a lower average gas content than the overlying Juandah Coal Measures. The obvious conclusion is that the difference in gas content is related to a difference in coal petrology. Not only do the gas contents of these coal intervals differ, their gas adsorption capacities also differ with the Taroom Coal Measures coals displaying, on average, lower gas content and lower gas adsorption capabilities. Again the obvious cause would be coal petrological differences, but the Juandah and Taroom Coal Measures coals have similar maceral percentages. An understanding of the relationship between gas desorption, gas adsorption and coal composition is vital in determining which areas in the basin offers the most economically viable targets for the commercialisation of coal seam gas in the Surat Basin.

Utility of coal petrology for sequence-stratigraphic analysis

Abstract Sequence stratigraphy seeks to predict the depositional architecture of sediments based on the principle that their superposition and lateral arrangement are largely determined by the rate at which accommodation is made below depositional base level relative to the supply rate of sediments. Depositional base level is generally correlated with sea level which in paralic peat/coal deposits controls the position of the groundwater table above which oxidation, ablation and erosion would occur. The current Late Quaternary sequence is used to discuss some of the constraints on coal formation that stem from the interaction of short- and long-period modulations on sequence-forming eustatic cycles. The results show that the mid-transgressive systems tract is unlikely to produce significant coal deposits, which is supported by a survey of the relevant literature from eight different countries. It reveals a bimodal distribution of coal deposits with the strongest mode being situated in the early transgressive systems tract, while a broader, secondary mode occurs in the early and mid-highstand position. This concentration contrasts with the complete absence of any significant coal deposits in the early and mid-lowstand systems tract, and only a low occupancy of the late highstand systems tracts. The reasons for this distribution are briefly discussed, and attention is drawn to the possible over-stating of the coal-forming potential of the late lowstand systems tract. Following a brief discussion of the sequence-stratigraphic interpretation of coal measures, emphasis is put on the application of sequence stratigraphy to the study of coal seams and their composition at various levels of petrographic detail. While in low-rank coals, botanical affinities contribute much to the lithotype-based analysis, a genetic assessment of bituminous coal seams relies primarily on physical and chemical palaeo-environmental signatures. Simple properties, such as maximum coal thickness, low detrital mineral content and maximum preservation of vitrinite, particularly of telovitrinite, define a good balance between the former rates of accommodation versus peat accumulation. Iso-metamorphic variations in telovitrinite reflectance and its dispersion measured by the coefficient of variation have also contributed to the palaeo-environmental interpretation. This paper confirms the identification within coal seams of most of the sequence-stratigraphically significant surfaces, e.g. sequence and parasequence boundaries, transgressive, flooding, and maximum flooding surfaces. It also gives examples of some new ones, referred to as accommodation reversal, non-marine flooding, give-up transgressive, terrestrialisation, and paludification surfaces. Some of these are specific to coal measures, but the give-up transgressive and accommodation reversal surfaces may have wider significance.

Petrology and chemistry of Permian coals from the Paraná Basin: 1. Santa Terezinha, Leão-Butiá and Candiota Coalfields, Rio Grande do Sul, Brazil

The current paper presents results on petrological and geochemical coal seam characterization in Permian coal-bearing strata from the Paraná Basin, southern Brazil. Sequence stratigraphic analysis shows that peat accumulation in Permian time was closely linked to transgressive/regressive cycles, with peat accumulation occurring in a predominantly back barrier/lagoonal setting. Coal petrographic analysis indicates subbituminous coals at Candiota and Leão-Butiá and high volatile bituminous coals at Santa Terezinha, where locally the coal seams are thermally altered by volcanic intrusions. Petrographic composition is highly variable, with seams at Candiota and Santa Terezinha frequently enriched in inertinite. Chemical analyses indicate that all coals are mineral matter-rich (mean 49.09 wt.%), with SiO 2 and Al 2 O 3 dominating as determined by ICP-AES. Quartz is also the predominant mineral detected by X-ray diffraction, where it is associated with feldspar, kaolinite and hematite and iron-rich carbonates. The results from Scanning Electron Microscopy are broadly consistent with the bulk chemical and mineralogical analysis. Quartz and clays are common in all samples analyzed. Other minerals observed were, amongst others, carbonates (calcite, siderite, ankerite), pyrite, monazite, kaolinite, barite, sphalerite, rutile and quartz of volcanic origin. The distribution of trace elements is well within the range typical for coal basins of other areas despite the fact that the Paraná Basin coals are very high in ash yields. The average concentrations for elements of environmental concern (As, B, Be, Cd, Co, Cr, Cu, Hg, Li, Mn, Mo, Ni, Pb, Sb, Se, Tl, U, V, Zn) are similar to or less than the mean values for U.S. coal. However, considered on an equal energy basis, Paraná Basin coals will produce in combustion 5 to 10 times the amount of most elements compared to an equal weight US coal. Concentrations of major and trace elements, such as Fe, B and S, appear to be controlled by depositional setting, with increasing values in coal seams overlain by brackish/marine strata. Hierarchical cluster analysis identified three groups of major minerals and seven groups of trace elements based on similarity levels. On a regional scale, the coalfields can be separated by the differences in rank (Candiota and Leão-Butiá versus Santa Terezinha) and by applying discriminant analysis based on 4 trace elements (Li, As, Sr, Sb). Highest Rb and Sr values occur at Candiota and are linked to syngenetic volcanism of the area, whereas high Y and Sr values at Santa Terezinha can be related to the frequent diabase intrusions in that area.

Development of coal petrography applied in technical processes at the Bergbau-Forschung/DMT during the last 50 years

Abstract The paper deals with the activities of the Bergbau-Forschung Coal Petrography Laboratory in Essen (Germany), which, under the influence of Marie-Therese Mackowsky, developed into a stronghold of the industrial application of coal petrology. In 1979, the formerly independent Section for Mineralogy and Petrology was merged with the Chemistry Section. This synergy has widened the research limits and resulted in higher efficiency of projects being carried out within both units. Since 1990, after transforming Bergbau-Forschung into DMT GmbH, a worldwide competition within hard coal and hard coal-based coke markets, together with the switch of the industry towards alternative energy sources, have significantly lowered the importance of the domestic coal mining industry. This in turn resulted in reduction of coal research programs. However, it is stressed that, in spite of transformations of the applied coal petrology experienced during the past 50 years, some achievements are still as applicable as ever. Among them, the method of predicting coke strength using maceral analysis and coal types, published by Mackowsky and Simonis [Mackowsky, M.-Th., Simonis, W., 1969. Die Kennzeichnung von Kokskohlen fur die mathematische Beschreibung der Hochtemperaturverkokung im Horizontalkammerofen bei Schuttbetrieb durch Ergebnisse mikroskopischer Analysen. Gluckauf-Forschungshefte 30, 25–27], is still in use today. The second part of this paper presents some examples of coal petrography applications, which are still important in carbonization processes. Mackowsky discovered that the pyrolytic components were influencing the coke homogeneity in coke ovens and affected coke quality parameters such as CRI and CSR. These highly graphitic layers and lenses prevent gasification of the inner zones of coke lumps, thus lowering the reactivity of metallurgical coke. Moreover, it also seems possible to predict wall load and maximum internal gas pressure as to prevent coke ovens from damage. Mathematic equations developed especially for the selection of coking coals and evaluation of coal blends for carbonization are also based on petrographic analyses, together with other factors such as bulk density and chamber width of the coke oven.

06/00004 Petrology of subbituminous feed coal as a guide to the capture of mercury by fly ash-influence of depositional environment: Goodarzi, F. International Journal of Coal Geology, 2005, 61, (1–2), 1–12

Stratigraphy, palynology, petrography, and geochemistry of the Bon Air coal from the Armfield, Dotson, Rutledge, and Shakerag mine sites of Franklin County, Tennessee suggest that Bon Air seams at all sites were small (≤ 1.0 mile, 1.6 km), spatially distinct paleomires that evolved from planar to domed within the fluviodeltaic Lower Pennsylvanian Raccoon Mountain Formation. Of observed palynoflora, 88–97% are from lycopsids prevalent in the Westphalian. Densosporites palynomorphs of small lycopsids (e.g., Omphalophloios) dominate at the shale-hosted Armfield site, while Lycospora palynoflora of large arboreous lycopsids (especially Lepidodendron, with lesser Lepidophloios harcourtii and Lepidophloios hallii) dominate where intercalated siltstone/sandstone/shale hosts the coal (all other sites). Palynoflora of other lycopsids (Sigillaria and Paralycopodites), tree ferns, seed ferns, small ferns, calamites, and cordaites are generally minor. Genera of clastic-associated Paralycopodites are most common in Shakerag's coal (≥ 10%), yet quite rare in Rutledge or Dotson coals. Overall, the palynomorph assemblages suggest that the Bon Air paleomires were forest swamps, and Early Pennsylvanian in age (Westphalian A, Langsettian).Dominant macerals at all sites are vitrinites, with fine collodetrinite (from strongly decomposed plant debris) more common than coarser collotelinite (from well-preserved plant fragments), and with lesser inertinites (fusinite and semifusinite) and liptinites (dominantly sporinite). Shakerag's coal has greatest abundance (mineral-matter-free) of collotelinite (up to 47%) and total vitrinite (74–79%) of any sites, but lowest liptinite (12–14.5%) and inertinite (7–11%). The Dotson and Rutledge seams contain moderate liptinite (21–23%) and highest inertinite (36–37%), lowest vitrinite (≤ 41%), and lowest collotelinite (13–15%). Armfield's seam has relatively high liptinite (26–28%) and vitrinite (56.5–62%), but rather low inertinite (12–15%). Moderately high ash (11.0–20.0%) and low to moderate sulfur (1.24% avg.) are typical, but ash may locally be up to 38% and sulfur up to 2.9%. Volatile matter (32.1–41.3%), calorific value (33.3–34.9 MJ/kg MAF), moisture (2.2–3.4%), and vitrinite reflectance (0.70–0.84% Rmax; 0.64–0.79% Rrandom) place the Bon Air's rank as high-volatile-A bituminous (hvAb).The Armfield coal was probably a channel-distal paleomire, perhaps an oxbow lake or floodplain depression, which domed and then subsided back to planarity prior to burial. Features of its basal and uppermost benches suggest low-lying, often-flooded (but periodically dry) mires marked by fluvial influxes and diverse lycopsid growth. These include variable inertinite, common palynoflora of both small lycopsids (Omphalophloios-like) and large arboreous ones (Lepidophloios and Lepidodendron), minor but significant palynoflora of subaerial levee or levee/mire transition species (especially Paralycopodites), moderate to high ash, variable sulfur, and elevated levels of commonly fluvial trace elements (e.g., Al, Cr, REEs, Rb, Sr, Th, V, Y, and Zr). These benches also contain high total vitrinite, high collotelinite/collodetrinite ratios, and clays with moderate to low kaolinite/quartz ratios, all consistent with the near-neutral pH and limited peat degradation that typify such planar mires. By contrast, middle benches at Armfield reflect mires domed above the land surface, less-often flooded, less-preservational, and of lower pH: coals have lower ash, vitrinite, and collotelinite, less palynoflora of both large arboreous lycopsids and Paralycopodites, and high proportions of kaolinite, liptinite, and Densosporites.Similar data at Shakerag suggest that its mire also grew from planar to domed. However, more abundant Paralycopodites, a kaolinite-poor but quartz-and-illite-rich underclay, benches alternately ash-rich and ash-poor, and an upper bench truncated by channel sandstone, suggest that it was channel-proximal and prone to intermittent clastics. It is unclear if it returned to planarity prior to burial. The mires at Dotson and (especially) Rutledge, with more ferns, more inertinite, less Paralycopodites and less vitrinite, were probably topographically elevated or protractedly domed mires, more vulnerable to drought or fire.

05/02399 Exploring the possibilities of using Brazilian subbituminous coals for blast furnace pulverized fuel injection

The basic coal quality parameters, coal petrology, mineralogy and geochemistry were investigated for coal seams 2, 3 and 4 (Permian Shanxi Formation) and 11, 12, 13 and 15 (Carboniferous Taiyuan Formation) of the Xinwen and Feicheng coal fields in the West Shandong mining district, East China. Rank parameters indicate a high volatile C to B bituminous rank for the Shandong coal. Coal from the Zhaizhen and Cha Zhuang mines is characterised by high vitrinite and low–middle inertinite and liptinite contents. Inertinite contents show an increase towards the top of the stratigraphic sequence from coal seams 15, 13 and 11 to coal seams 4 and 2. This trend may be related to a stratigraphic trend characterised by the evolution of relatively more reducing conditions of the synsedimentary coal forming environment in the early Taiyuan coals (marine-influenced lower delta plain) to more oxidising paleoenvironments of the Upper Shanxi coal seams (upper delta plain). Major mineral phases present in the Shandong coal are quartz, kaolinite, pyrite and calcite. Traces of other primary minerals (dolomite, ankerite, illite, opal, feldspars and marcasite) and weathering products (gypsum, melanterite and hematite) can be found in several coal seams. The Lower Permian coal seams (two to four) have a lower mineral content (8–14% ash db) than the Upper Carboniferous coal seams (15–37% ash db), owing to the lower proportions of quartz and sulphide mineral. The occurrence and distribution of the different minerals in the Shandong coal indicates a paragenetic sequence characterised by an early syngenetic stage (detrital minerals, framboidal, euhedral and massive cell-filling pyrite, ankerite, neomorphic quartz and kaolinite), middle and late syngenetic stages (radial and fibrous marcasite aggregates, massive pyrite) and an epigenetic stage (carbonates and sulphides as cleat filling). A clear differentiation exists between the Shanxi and the Taiyuan coal seams, based on the higher sulphide contents of the Taiyuan coal (3.3 to 6.2% S db) compared with the Shanxi coal (0.4 to 0.8% S db). This differentiation is related to marine influence on the depositional environment of coal seams 11 to 15, which has been reported by earlier studies. Vertical variations of the abundance of major and trace elements are discussed on the basis of this differentiation. An epigenetic external enrichment of Ge, Mo and U at the top of most of the coal seams is observed, and major and trace element affinities are deduced for the West Shandong coal.

Measuring surface properties and oxidation of coal macerals using the atomic force microscope

Early microscopic examination of coals and coal macerals began with the use of transmitted and then reflected light microscopy. These methods were limited by the resolution and optical quality of the microscopes used. Improved microscope technology and the development of oil immersion techniques led to advancements in coal petrology. Introduction of the atomic force microscope (AFM) has led to higher resolution (angstrom and nanometer scale) imaging of various inorganic and organic surfaces with ability to quantitatively measure surface features and forces, but the use of AFM for measuring coal surfaces has been limited by a lack of a method to identify the macerals being analyzed. This paper describes a method using AFM to identify individual macerals and precisely measure their surface properties through the use of various AFM modes and analyses. This method has the potential to yield useful information about the physical properties of coal macerals (e.g. topography, roughness, hardness, and elastic modulus), and also about the effects of natural oxidation on coal macerals and the intentional oxidation of individual macerals to enhance either optical properties or surface porosity.

Organic petrology in the 19th, 20th, and 21st centuries: The Newcastle contribution

The paper describes the development of coal petrology, then organic petrology, over a period of approximately 175 years around and in Newcastle upon Tyne (England). From 1833 until 1950, the basis of study was essentially transmitted light microscopy. In this period, perhaps the supreme contribution was the work of Hutton, Lindley, and Witham, who demonstrated the vegetable nature of coal in 1833. A major Scottish legal case, the ‘Boghead Controversy’ of 1853, in which ‘Newcastle’ was much later to be involved, was not finally resolved until Blackburn and Temperly confirmed the true nature of the relationship between the modern alga Botryococcus and the algal coals some 80 years later. In the early part of the 20th century, works by Hickling on the ‘coal belt’ and Hickling and Marshall on the cell structures of vitrinites were important as was Raistrick's substantial contribution to the founding of the field of palynology through his microspore correlation studies on coal seams from the coalfields of northeast England and Lancashire. Large-scale organisational changes in the Department of Geology at Newcastle in the period 1950 to 1989 took place with the development of the Organic Geochemistry Unit (OGU) in which organic petrology was a major component. Organic petrology and organic geochemistry were major components. There was almost entire replacement of transmitted light microscopy by reflected light procedures as the principal means of studying crustal organic matter microscopically. Widespread collaboration with industry, particularly with oil companies, which, with the University and the Research Councils, provided invaluable support to the research group over many years. Considered here are the results of investigations across the expanding field of organic petrology, covering the development of equipment and relationships between maceral properties, the varied effects of carbonisation treatments, and the influence of igneous activity on crustal organic matter. There were further radical changes in the composition of the research group after the completion of the national Earth Science Review in 1989. The Institute of Fossil Fuels and Environmental Geochemistry (FFEGI) was formed with a further substantial increase of both staff and postgraduate students. Organic petrology as a component was much reduced, although reflected light studies continued on coals from the offshore coalfields of northeast England, and transmitted light studies, almost exclusively related to the study of organic facies, returned. The output of organic petrologists virtually ceased. Most effective research groups, however, shift their emphases with time. FFEGI occupied a substantial and successful international research niche within the environmental field, as well as being still heavily committed to petroleum geochemistry until 2003 when FFEGI was integrated within the new School of Civil Engineering and Geosciences.

Marlies Teichmüller (1914–2000), pioneering genetic coal petrologist: some paleobotanical, palynological, and botanical influences on her research

Marlies Teichmüller focused her career on genetic coal petrology. In her investigations of the botanical components of coal and reconstructions of Carboniferous and Tertiary mires, she was greatly influenced by Eric Stach, Walther Gothan, Reinhardt Thiessen, Rolf Teichmüller, Paul Thomson, Gilbert Cady, and William Spackman, Jr. Some of these influences deal with paleobotany, palynology, and botany and these are set forth in this tribute.