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- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
A global exploration of coal geology, from production and use to chemical properties and coal petrology
Coal Geology, 3rd Edition, offers a revised and updated edition of this popular book which provides a comprehensive overview of the field of coal geology including coal geophysics, hydrogeology and mining. Also covered in this volume are fully revised coverage of resource and reserve definitions, equipment and recording techniques together with the use of coal as an alternative energy source as well as environmental implications.
This third edition provides a textbook ideally suited to anyone studying, researching or working in the field of coal geology, geotechnical engineering and environmental science.
- Fills the gap between academic aspects of coal geology and the practical role of geology in the coal industry
- Examines sedimentological and stratigraphical geology, together with mining, geophysics, hydrogeology, environmental issues and coal marketing
- Defines global coal resource classifications and methods of calculation
- Addresses the alternative uses of coal as a source of energy
- Covers a global approach to coal producers and consumers
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Seitenzahl: 991
Veröffentlichungsjahr: 2020
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Table of Contents
Cover
Preface to Third Edition
Preface to Second Edition
Preface to First Edition
List of Acronyms
1 Preview
1.1 Scope
1.2 Coal Geology
1.3 Coal Use
1.4 Background
2 Origin of Coal
2.1 Introduction
2.2 Sedimentation of Coal and Coal‐Bearing Sequences
2.3 Structural Effects on Coal
3 Age and Occurrence of Coal
3.1 Introduction
3.2 Plate Tectonics
3.3 Stratigraphy
3.4 Age and Geographical Distribution of Coal
4 Coal as a Substance
4.1 Physical Description of Coal
4.2 Coalification (Rank)
4.3 Coal Quality
4.4 Classification of Coals
5 Coal Sampling and Analysis
5.1 Coal Sampling
5.2 Coal Analysis
6 Coal Exploration and Data Collection
6.1 Introduction
6.2 Field Techniques
6.3 Drilling
6.4 Geotechnical Properties
6.5 Computer Applications
7 Coal Resources and Reserves
7.1 Introduction
7.2 Coal Resources and Reserves Classification
7.3 Reporting of Resources/Reserves
7.4 World Coal Reserves and Production
8 Geophysics of Coal
8.1 Introduction
8.2 Physical Properties of Coal‐Bearing Sequences
8.3 Surface Geophysical Methods
8.4 Underground Geophysical Methods
8.5 Geophysical Borehole Logging
9 Hydrogeology of Coal
9.1 Introduction
9.2 The Nature of Groundwater and Surface Flow
9.3 Hydrogeological Characteristics of Coals and Coal‐Bearing Sequences
9.4 Collection and Handling of Hydrogeological Data
9.5 Groundwater Inflows in Mines
9.6 Groundwater Rebound
10 Geology and Coal Mining
10.1 Introduction
10.2 Underground Mining
10.3 Surface Mining
10.4 Coal Production
11 Coal as an Alternative Energy Source
11.1 Introduction
11.2 Gas in Coal
11.3 Underground Coal Gasification
11.4 Coal as a Liquid Fuel
12 Coal Use and the Environment
12.1 Introduction
12.2 Coalmining
12.3 Coal Use
12.4 Health
12.5 Carbon Capture and Storage
12.6 Environmental Regulations
12.7 Future Implications
13 Coal Marketing
13.1 Introduction
13.2 Coal Quality
13.3 Transportation
13.4 Coal Markets
13.5 Coal Contracts
13.6 Coal Price and Indexing
Appendix A: Appendix A List of International and National Standards Used in Coal and Coke Analysis and Evaluation
A.1 British Standards Institution (BS)
A.2 International Organization for Standardization (ISO)
A.3 ASTM International, Formerly Known as American Society for Testing and Materials (ASTM)
A.4 Standards Association of Australia (AS)
A.5 National Standards of People's Republic of China
A.6 Bureau of Indian Standards
A.7 State Standards of Russia – GOST (GOST = Gosudarstvennyy Standart)
Appendix B: Appendix B Tables of True and Apparent Dip, Slope Angles, Gradients, and Percentage Slope
Appendix C: Appendix C Calorific Values Expressed in Different Units
Appendix D: Appendix D Coal Statistics
Appendix E: Appendix E Methane Units Converter
Glossary
Bibliography
Index
End User License Agreement
List of Tables
Chapter 2
Table 2.1 Sedimentary features used to identify depositional environments.
Table 2.2 Classification of mires.
Table 2.3 The average structural index (ASI) for coals.
Chapter 3
Table 3.1 Detailed chronostratigraphy and biostratigraphy of the Carboniferou...
Chapter 4
Table 4.1 Lithotypes of humic and sapropelic coals.
Table 4.2 Macroscopic description of coals in sections and boreholes.
Table 4.3 Macroscopic description of lignites.
Table 4.4 Lithotype classification for soft brown coals.
Table 4.5 Typical characteristics of air‐dried brown coal lithotypes from Lat...
Table 4.6 Stopes–Heerlen classification of maceral groups, macerals, and subm...
Table 4.7 Maceral terminology and origin (Speight 1994).
Table 4.8 Composition of microlithotypes.
Table 4.9 Huminite macerals.
Table 4.10 Australian maceral classification of brown coals.
Table 4.11 Characteristics of Palaeogene–Neogene lignite facies.
Table 4.12 Minerals identified in coal (not exhaustive).
Table 4.13 Contents of trace elements in coals, soils, and shales (as ppm).
Table 4.14 Major stages of the development from peat to meta‐anthracite.
Table 4.15 Rank classes in terms of vitrinite reflectance.
Table 4.16 Some rank parameters showing the changing pattern of coal composit...
Table 4.17 Components of coal reporting to different bases.
Table 4.18 Formulae for calculation of results to different bases.
Table 4.19 Characteristics for classification of Gray–King coke type.
Table 4.20 Grading standards for mechanical strength of coal (Xie 2015).
Table 4.21 Washability data.
Table 4.22 Parameters used in Seyler's coal classification.
Table 4.23 ASTM classification of coals by ranka.
Table 4.24 Coal classification system used by British Coal (revision of 1964)...
Table 4.25 Codification system used by UNECE (1988) for medium‐ and high‐rank...
Table 4.26 Australian classification of hard coal.
Table 4.27 Classification of low‐rank coals UNECE (2002).
Table 4.28 Codification system used by UNECE (2002) for low‐rank coals.
Table 4.29 Classification of Russian coals Yeriomin (1988).
Table 4.30 Comparison of GOST and ASTM Standard Classification of Coals. US o...
Table 4.31 Classification of Chinese coals (GB/T5751‐86; Lu and Laman 2012).
Chapter 5
Table 5.1 Minimum number of increments required for gross samples of a single...
Chapter 6
Table 6.1 Core sizes for wireline, conventional, and air‐flush drilling.
Table 6.2 Terms used to assess material strength in the field.
Table 6.3 Terms used to describe degree of weathering in the field.
Table 6.4 Terms used to describe the bedding spacing in the field.
Table 6.5 Terms used to describe discontinuities in the field.
Chapter 7
Table 7.1 UNFC‐2009 classes and sub‐classes defined by subcategories (UNECE 2...
Table 7.2 Russian resource/reserves classification (Dixon 2010).
Table 7.3 Comparisons between CRIRSCO and other resource and reserve classifi...
Table 7.4 Update of Chinese coal classification codes (Li 2015).
Table 7.5 Mapping of GB/T 17766‐1999 to UNFC‐2009 classes and categories (UNE...
Table 7.6 World coal reserves (million tonnes).
Table 7.7 World coal production (million tonnes oil equivalent).
Table 7.8 World coal consumption (million tonnes oil equivalent).
Chapter 8
Table 8.1 Table of physical properties of coals and associated sedimentary an...
Chapter 9
Table 9.1 Indicative porosities and hydraulic conductivities for unconsolidat...
Table 9.2 Gross open‐pore distributionsa in coals.
Chapter 10
Table 10.1 Coal burst risk analysis for longwall mining in the USA.
Table 10.2 Dragline and BWE capacities currently in use.
Table 10.3 Size and capacity of a selection of electric and hydraulic excavat...
Table 10.4 Percentage of underground/opencast coal production in world's five...
Table 10.5 World's top 10 brown‐coal producers.
Chapter 11
Table 11.1 Gross open‐pore distribution in coals.
Table 11.2 Estimated CMM and AMM projects and utilisation.
Table 11.3 Major coal resources (BP Statistical Review 2011) and estimated CB...
Table 11.4 CBM proved reserves and production from principal US producing are...
Table 11.5 Parameters of coal gas products of some representative UCG project...
Table 11.6 Desired underground coal gasification site characteristics.
Table 11.7 Efficiencies from typical large US UCG pilot test (P. Ahner, perso...
Table 11.8 UCG production in the former USSR.
Table 11.9 Examples of case studies of petroleum systems derived from terrige...
Chapter 12
Table 12.1 Changes in groundwater quality with depth.
Table 12.2 Selected analyses (in mg l
−1
) of deep waters from coal measu...
Table 12.3 Normal range coal specifications for pf‐fired boilers.
Table 12.4 Emission limits for existing and new power plants in selected majo...
Table 12.5 Distribution of elements among bottom ash, fly ash, and flue gas (...
Table 12.6 Selected mitigation technologies for air pollutants in power gener...
Chapter 13
Table 13.1 Throughput of major exporting/importing ports (www.sourcewatch.org...
Table 13.2 Major coal exporting and importing countries (WCA 2018).
Table 13.3 Principal producers of coal‐fired electricity generation 2015 (IEA...
List of Illustrations
Chapter 2
Figure 2.1 (a) Barrier and back‐barrier environments including tidal channel...
Figure 2.2 Generalised vertical sequences through lower delta plain deposits...
Figure 2.3 (a) Reconstruction of transitional lower delta plain environments...
Figure 2.4 (a) Reconstruction of upper delta plain–fluvial environments in K...
Figure 2.5 Depositional model of a humid anastomosed river based on Westphal...
Figure 2.6 Proposed relationship between mires in terms of the relative infl...
Figure 2.7 Evolutionary sequence of swamp types showing the development of a...
Figure 2.8 Theoretical model of fluvial architecture in areas of raised swam...
Figure 2.9 Late Palaeozoic plant assemblages, Weibei Coalfield, PRC. (A)
Cal
...
Figure 2.10 Selected megaspores from the Low Barnsley Seam. (a)
Lagenicula s
...
Figure 2.11 Schematic diagram of idealised uninterrupted sequence of megaspo...
Figure 2.12 Early Permian macrofossil assemblages, Parana Basin, Brazil. (A)...
Figure 2.13 Cartoon illustrating the concept of sequence stratigraphy and it...
Figure 2.14 Simplified asymmetrical glacio‐eustatic sea‐level curves showing...
Figure 2.15 Diagrammatic model of a number of sequence stratigraphic setting...
Figure 2.16 Cross‐section showing portions of superimposed mouth‐bar lobes w...
Figure 2.17 Cross‐section showing stratigraphic relations of coals and sands...
Figure 2.18 Cross‐section showing correlation of lithofacies and associated ...
Figure 2.19 Fence correlation diagram showing the geometry of a coal and san...
Figure 2.20 Correlation based on geophysical logs, Coalspur Beds, Upper Cret...
Figure 2.21 Lithofacies map illustrating how such mapping can be extended to...
Figure 2.22 Mapped lithotypes compiled from 1000 boreholes over an area of 1...
Figure 2.23 Lithofacies map of part of the Patchawarra Formation (Permian) S...
Figure 2.24 Palaeogeographic reconstruction of the same interval as shown in...
Figure 2.25 Development of a coal seam splitting in the Beckley Seam across ...
Figure 2.26 Common types of coal seam split: (a) simple splitting; (b) multi...
Figure 2.27 Channelling in coal seams. (a) Sand‐filled channel producing a s...
Figure 2.28 Isopach maps of the north‐eastern Fuxin Basin, PRC, showing (a) ...
Figure 2.29 Coal seam thickness isopach map; hypothetical example (thickness...
Figure 2.31 Normal‐fault reactivation causing instability in a partially coa...
Figure 2.30 Deformed bedding in Palaeogene–Neogene coal‐bearing sediments, E...
Figure 2.32 Cores exhibiting a ‘melange’ or mixing of lithotypes due to grav...
Figure 2.33 Seam splitting caused by differential movement of faults during ...
Figure 2.34 Section across Belchatow opencast mine, Poland, showing effect o...
Figure 2.35 Schematic illustrating cleat geometrics. (a) Cleat‐trace pattern...
Figure 2.36 (a) Orthogonal cleat pattern in Meltonfleet Coal, Upper Carbonif...
Figure 2.37 Normal fault with downthrow of 2 m to the right. Palaeogene–Neog...
Figure 2.38 Highwall termination due to faulting in Palaeogene–Neogene brown...
Figure 2.39 Normal fault downthrowing overburden (light colour) against a co...
Figure 2.40 Large fault zone exposed in highwall in an opencast mine, South ...
Figure 2.41 Lag fault produced by retardation of the upper part of the seque...
Figure 2.42 Coal seam dislocated by reverse fault, with throw of 1.5 m, in U...
Figure 2.44 Model for four stages in progressive easy‐slip thrusting. (a) Th...
Figure 2.43 Highly sheared anthracite coal seam (seam thickness 1.2 m) in op...
Figure 2.45 The coal Bedding Code, showing five categories of bedding plane ...
Figure 2.47 (a) Tectonic deformation of coal seams due to compression: (i) s...
Figure 2.46 Intensely folded Carboniferous coal‐bearing sediments, Little Ha...
Figure 2.48 Outcrop patterns in folded coalfields. (a) Zigzag folding of coa...
Figure 2.49 Jurassic anthracite (dark colour) intruded by granitic dykes and...
Chapter 3
Figure 3.1 Geological age distribution of the world's black coal and lignite...
Figure 3.2 Palaeogeographical reconstructions of (a) late Carboniferous and ...
Figure 3.3 Palaeogeographic reconstruction of (a) Jurassic–Cretaceous and (b...
Figure 3.4 Detailed stratigraphy of the Westphalian succession for the Wakef...
Figure 3.5 Stratigraphic correlation based on faunal horizons and coals (Wor...
Figure 3.6 Use of lithological and electric logs to show the stratigraphic r...
Figure 3.7 Coal deposits of the USA. A, Eastern Province; B, Interior Provin...
Figure 3.8 Coal deposits of Canada: (1) south Saskatchewan; (2) central and ...
Figure 3.9 Coal deposits of Europe: (1) Tirane; (2) Tepelene; (3) Korce; (4)...
Figure 3.10 Coal deposits of Africa. (1) Lungue‐Bungo; (2) Luanda; (3) Morop...
Figure 3.11 Coal deposits of the Indian subcontinent. (1) Heart; (2) Sari‐i‐...
Figure 3.12 Coal deposits of South America. (1) La Rioja; (2) San Juan; (3) ...
Figure 3.13 Coal deposits of the Commonwealth of Independent States: Donbass...
Figure 3.14 Coal deposits of the Far East. (1) Bandar Seri Begawan; (2) Bela...
Figure 3.15 Coal deposits of Australasia. Australia: (1) Collie Basin; (2) F...
Chapter 4
Figure 4.1 Diagrammatic representation of microlithotype classification.
Figure 4.2 Microlithotypes: (a) vitrite from a high‐volatile Ruhr coal, poli...
Figure 4.3 Microlithotype analysis related to depositional environment, for ...
Figure 4.4 Diagrammatic profile of a coal seam showing the sequence of miosp...
Figure 4.5 Ternary diagram showing ash chemistry of some of Western Canada's...
Figure 4.6 Petrographic compositions of coking coals traded internationally....
Figure 4.7 Characteristics of coke attainable from bituminous coals.
Figure 4.8 Diagram showing the coalification tracks of liptinite, inertite, ...
Figure 4.9 (a) Rank scale of coal using axes of volatile matter and CV (Sugg...
Figure 4.10 Composite sequence providing an example of the relationship betw...
Figure 4.11 Generalised variation of capacity (or air‐dried) moisture conten...
Figure 4.12 Characteristic profiles of coke buttons for different values of ...
Figure 4.13 Relationship between coal rank, coal type, and fluorescence.
Figure 4.14 Generalised variation of the Hardgrove grindability index with r...
Figure 4.15 Washability curves based on data given in Table 4.18.
Figure 4.16 Middlings or M curve.
Figure 4.17 Seyler's coal chart. This version shows relationships between el...
Figure 4.18 UNECE main coal classification categories, defined by gross CV (...
Figure 4.19 Interrelationships of coal classification systems used in variou...
Chapter 5
Figure 5.1 Channel sampling procedure: (a) whole seam channel sampling; (b) ...
Figure 5.2 Coal outcrop data card.
Figure 5.3 Surface coal ply channel sample taken in shallow dipping seam. Ce...
Figure 5.4 Ply sampling of borehole core; run of samples to include all the ...
Figure 5.5 Three‐stage mechanical sampling system (Membrey 2013).
Figure 5.6 Decision flow chart for determining sampling system requirement (...
Figure 5.7 The collection of a stop belt sample from a main conveyor (Mazzon...
Figure 5.8 Sample preparation diagram for drill core samples from a steam (t...
Figure 5.9 Sample preparation diagram for drill core samples from a coking (...
Figure 5.10 Sample preparation diagram for bulk sample(s) from a steam (ther...
Figure 5.11 Sample preparation diagram for bulk sample(s) from a coking (met...
Chapter 6
Figure 6.1 Flow diagram to show principal activities requiring a geological ...
Figure 6.2 Field equipment used by coal geologists.
Figure 6.3 Symbols for geological maps.
Figure 6.4 Graphic portrayal of principal lithotypes in coal‐bearing sequenc...
Figure 6.5 Typical traverse survey showing coal outcrops, sample sites, and ...
Figure 6.6 Field map of a UK coalfield area, showing geology and past and pr...
Figure 6.7 Varieties in black (hard) coal. (a) Banded bituminous coal from N...
Figure 6.8 Graphic representation of coal seams, based on Australian Standar...
Figure 6.9 Graphic representation of coal seams as used in UK.
Figure 6.10 Example of a graphic representation of coal seams as used in the...
Figure 6.11 (a) Hand‐held GPS receiver, Magellan Triton 400.(b) Rugged t...
Figure 6.12 Photogeological symbols for use on aerial photographs and photog...
Figure 6.13 Drilling procedure to correctly complete a borehole containing o...
Figure 6.14 Dando dual air–mud‐flush rig mounted on a bulldozer for use in d...
Figure 6.15 (a) Edeco rig operating in the UK; (b) Mayhew 1000 truck mounted...
Figure 6.16 (a) Mintec 12.8 exploration drilling rig; (b) Dando Multitec 900...
Figure 6.17 Borehole core laid out in wooden boxes with depth markers, await...
Figure 6.18 Exploration drilling grid showing distribution and position of o...
Figure 6.19 Portable drilling rig using manpower to exert downward pressure ...
Figure 6.20 Voyager V2200 portable drilling rig.
Figure 6.21 Coal geologist logging borehole core in a core shed on‐site.
Figure 6.22 Borehole core photographed to show special features. In this ins...
Figure 6.23 Example of a core logging sheet used by the coal geologist in th...
Figure 6.24 Coal geologist logging borehole chip samples in an on‐site core ...
Figure 6.25 (a) Schmidt hammer (West 1991); (b) Point load tester (West 1991...
Figure 6.26 Correlation curve for type N19 Schmidt hammer used with Carbonif...
Figure 6.27 Types of discontinuities, including bedding and joints that have...
Figure 6.28 Example of a geotechnical logging sheet.
Figure 6.29 Computer‐generated borehole location plan.
Figure 6.30 (a) Coal thickness contour map with borehole locations. (b) Full...
Figure 6.31 (a) Total sulfur content contour map with borehole locations. (b...
Figure 6.32 Simplified flow diagram of a geological contouring programme....
Chapter 7
Figure 7.1 Relationship between exploration results, mineral resources, and ...
Figure 7.2 UNFC‐2009 resource and reserve categories and examples of classes...
Figure 7.3 Criteria for distinguishing coal resource categories, adapted fro...
Figure 7.4 Diagram showing reliability categories based solely on distance f...
Figure 7.5 Comparison of Russian and CRIRSCO classifications (Dixon 2010).
Figure 7.6 Variable factors in coal reserves assessment.
Figure 7.7 Digital planimeter being used to calculate coal reserve areas wit...
Figure 7.8 Polygon method for calculation of in‐situ coal resources/reserves...
Figure 7.9 Construction of polygons (blocks) of influence for an equiangular...
Figure 7.10 Variogram of ash content over distance.
Figure 7.11 Variogram of coal thickness.
Figure 7.12 Schematic diagram of the calculation of sectional areas using th...
Figure 7.13 Effects of geological structure and topography on stripping rati...
Figure 7.14 Coal production and consumption from 1985 to 2010.
Figure 7.15 Fossil fuel R/P ratios at end 2010.
Chapter 8
Figure 8.1 Seismic reflection survey, showing field data acquisition and sei...
Figure 8.2 Seismic section showing a robust and continuous coal seam reflect...
Figure 8.3 (a) Shallow seismic reflection survey, Northern Ireland, UK. (b) ...
Figure 8.4 Depth seismic profile with interpreted faults.
Figure 8.5 Seismic profile showing anticline structure of Wyodak coal and th...
Figure 8.6 Seismic reflection profile showing a buried channel at a depth of...
Figure 8.7 Seismic exploration showing a fault in section (upper) and time s...
Figure 8.8 Seismic depth section obtained from the hole‐to‐surface survey in...
Figure 8.9 (a) Coal seam stratigraphy for three boreholes at an opencast sit...
Figure 8.10 Reprocessed seismic data line showing stronger reflections and s...
Figure 8.11 A 2D pseudo‐section of contoured shear‐wave velocity data showin...
Figure 8.12 Bouguer anomaly map of the Collie Coalfield, Western Australia....
Figure 8.13 Magnetic anomaly map for part of the Causey Park dyke, UK. Conto...
Figure 8.14 High‐resolution aeromagnetic survey over an Eastern Transvaal co...
Figure 8.15 Magnetic profile over burnt coal and geological cross‐section, E...
Figure 8.16 Total magnetic field profile and geological cross‐section, south...
Figure 8.17 Conceptual behaviour of channel waves on encountering (a) a coal...
Figure 8.18 Four line seismic sections, 240 ft (c. 73 m) apart, showing roll...
Figure 8.19 ISS reflection survey used to detect faulting in advance of long...
Figure 8.20 Probing distances as a function of frequency for different geolo...
Figure 8.21 Mobile geophysical logging unit.
Figure 8.22 Coal‐bearing sequence lithotypes and gamma‐ray log response.
Figure 8.23 Section showing gamma, density, and resistivity logs over a prin...
Figure 8.24 Long‐spaced density log response to coal.
Figure 8.25 Response of neutron log over a coal seam.
Figure 8.26 Use of the combination of calliper and density logs to determine...
Figure 8.27 Response of resistivity log to coal‐bearing lithotypes.
Figure 8.28 Response of density and resistivity logs over a burnt coal zone....
Figure 8.29 Dipmeter tadpole plot at the target seam depth, Fillongly Hall b...
Figure 8.30 Response of sonic log to coal‐bearing lithotypes.
Figure 8.31 (a) Breakout as it appears on amplitude (left) and transit time ...
Figure 8.32 Interpretation of coal rank from sonic and density logs.
Figure 8.33 Density log interpretation together with interpreted coal seam b...
Figure 8.34 Combination of lithological, sonic, and gamma logs to identify c...
Figure 8.35 Cross‐plot of depth‐matched gamma‐ray and density data.
Figure 8.36 Computed lithology analysis derived from data shown in Figure 8....
Figure 8.37 Summary of log responses in various lithologies.
Chapter 9
Figure 9.1 Groundwater conditions in a coal‐bearing sequence, showing an upp...
Figure 9.2 Drawdown of the water table due to pumping in an unconfined aquif...
Figure 9.3 Piezometer group measuring water levels in two formations in an o...
Figure 9.4 Pumping test in operation in the Thar Coalfield, Pakistan.
Figure 9.5 Section across proposed opencast pit showing position of observat...
Figure 9.6 Floor heave resulting from upward artesian pressure.
Figure 9.7 Types of opencast mining in which advance dewatering methods are ...
Figure 9.8 Site dewatering. A two‐stage dewatering scheme using well points ...
Figure 9.9 Migration of the cone of depression due to pumping.
Figure 9.10 Schematic view of equipment for a dewatering well (Pavlovic 2012...
Figure 9.11 Designed dewatering facilities for groundwater control at Drmno ...
Figure 9.12 System for protecting Drmno open‐pit mine against water incursio...
Figure 9.13 Theoretical study to predict the decline in water level for a pr...
Figure 9.14 Rebound effect on the water table after cessation of opencast mi...
Chapter 10
Figure 10.1 Methods of entry for underground mines: (a) in‐seam adit; (b) in...
Figure 10.2 Methods of mining in underground mines: (a) longwall advance min...
Figure 10.3 Longwall mining equipment. (a) Rotary drum shearer, Huabei mine,...
Figure 10.4 Methods for longwall mining in thick seams: (a) multiple slicing...
Figure 10.5 Effects of changes in coal seam development on longwall mining. ...
Figure 10.6 EIMCO Dash 3 continuous miner in operation in Alabama, USA.
Figure 10.7 World stress maps of USA, Australia, and northern Europe showing...
Figure 10.8 Stress redistribution about a retreating longwall panel.
Figure 10.9 Optimised longwall layout and working sequence for high horizont...
Figure 10.10 Possible layouts to minimise horizontal‐stress effects for a ro...
Figure 10.11 Borehole breakout log showing minimum and maximum callipers. Br...
Figure 10.12 Final layout design for an underground mine development, with s...
Figure 10.13 The range of underground measurements and laboratory rock tests...
Figure 10.14 A 3D contour map showing SR schedule after (a) three years and ...
Figure 10.15 Dragline removing overburden in opencast mine, USA.
Figure 10.16 (a) Electric shovel removing overburden, in central India. This...
Figure 10.18 (a, b) Truck fleets transporting overburden from shovel to dump...
Figure 10.17 Large dump truck (280 t) being loaded at Fording coalmine, Cana...
Figure 10.19 (a) BWE cutting overburden in Gacko lignite mine, Bosnia‐Herzeg...
Figure 10.20 (a) Large‐scale benched mining operation, Anjaliang opencast mi...
Figure 10.21 (a) Truck and shovel operation, Shotton opencast mine, Northumb...
Figure 10.22 Wirtgen surface strip miner in operation in Gacko mine, Bosnia‐...
Figure 10.23 Schematic image of a highwall mining operation.
Figure 10.24 Auger mining in Bottom Busty seam, Shotton opencast mine, North...
Figure 10.25 Multiple rail system in Ekibastuz mine, Kazakhstan.
Chapter 11
Figure 11.1 Generation of gases with depth, C
2+
represents hydrocarbons ...
Figure 11.2 Adsorptive capacity of coal as a function of rank and depth.
Figure 11.3 Typical CBM isotherm characteristic of San Juan Basin coal (Baim...
Figure 11.4 Map of cleat system in the Piceance Basin, Colorado, USA (Laubac...
Figure 11.5 Map of UK selected cleat directions (red) and cleats without rec...
Figure 11.6 CBM and CMM options for CH
4
extraction and utilisation (Departme...
Figure 11.7 CH
4
extraction from active mine workings.
Figure 11.8 Pattern of drainage holes ahead of a panel front, Metropolitan C...
Figure 11.9 Reduction of gassiness resulting from pre‐drainage.
Figure 11.10 (a) Coal‐bed gas recovery by reservoir pressure depletion.(...
Figure 11.11 US CBM production 1985–2016 (www.wikipedia.org 2017).
Figure 11.12 Coal‐bed gas resources of the USA (in TCF); includes probable, ...
Figure 11.13 Coal/CBM accumulation provinces of PRC.Orogenic belts: I Yinsha...
Figure 11.14
Figure 11.15 Principal sedimentary basins with oil and gas potential, in New...
Figure 11.16 Extent of Westphalian Coal Measures and CBM development in the ...
Figure 11.17 The main components of a commercial UCG site for power generati...
Figure 11.18 Typical configuration for steeply dipping bed gasification.
Figure 11.19 (a) Plan and cross‐section views of a UCG panel before gasifica...
Figure 11.20 (a) Injection and production wells using the CRIP technique. (b...
Figure 11.21 Schematic diagram of hydrogeologic relationships under high‐ an...
Figure 11.22 Comparison of kerogen types, evolution paths, and petrographic ...
Figure 11.23 Characterisation of source rock maturity by pyrolysis methods. ...
Figure 11.24 Hydrocarbon reserves tied to coal‐bearing source sequences by a...
Chapter 12
Figure 12.1 Physical and chemical effects on the environment due to coalmini...
Figure 12.2 Selective handling and placement of mine spoil to prevent the fo...
Figure 12.3 Plan of Merthyr Vale (Aberfan) colliery tip flow slides of 1944,...
Figure 12.4 Opencast mine in Bosnia‐Herzegovina showing large‐scale overburd...
Figure 12.5 Opencast mine in Maharashtra State, India, showing protective bu...
Figure 12.6 (a) Coal burning as a result of ignition by forest fires in Kali...
Figure 12.7 Strata disturbance and subsidence caused by mining.
Figure 12.8 Influence of extraction width on subsidence.
Figure 12.9 Subsided land overlying underground workings, the PRC, now flood...
Figure 12.10 Schematic representation of ground movements due to subsidence....
Figure 12.11 Collapse of capping material over an old concealed shaft in a m...
Figure 12.12 Schematic view of the upward migration of mine gas by means of ...
Figure 12.13 Modern coal‐fired power station, Inner Mongolia, PRC.
Figure 12.14 Flow diagram showing stages from coal delivery to electricity g...
Figure 12.15 Schematic flow diagram of a limestone–gypsum FGD process.
Figure 12.16 Typical emissions control systems for power plants (IEA 2016)....
Figure 12.17 Local coke manufacture in small ‘ovens’, Guizhou Province, PRC....
Figure 12.18 The 2015 fuel shares of CO
2
emissions from fuel combustion (IEA...
Chapter 13
Figure 13.1 Section through a Baum‐type jig. Coal is fed into the jig and th...
Figure 13.2 Coal silos for loading coal directly to trains, the PRC.
Figure 13.3 Modern coal stockyard at port of Qinhuangdao, PRC.
Figure 13.4 Overland conveyor, 14 km in length, from Kaltim Prima Coalmine t...
Figure 13.5 Coal transportation by small capacity 10 t truck, India.
Figure 13.6 Automatic loading of trucks from overhead bins, Orissa State, In...
Figure 13.7 Automatic loading of trains, Alberta, Canada. Each wagon receive...
Figure 13.8 Train being loaded by payloader, Orissa State, India.
Figure 13.9 Bottom‐discharge wagons (60 t), on Eastern Railways, India.
Figure 13.10 Large train units transporting 12 000 t over 1200 km in the wes...
Figure 13.11 Top‐discharge wagons with drop‐down doors for side unloading. G...
Figure 13.12 Coal barges carrying up to 10 000 t, Mississippi River, USA.
Figure 13.13 Coal loading directly into the ship from the stockyard conveyor...
Figure 13.14 Principal coal export routes to markets in western Europe and t...
Figure 13.15 Global electricity generation by source (IEA 2017). 1: includes...
Figure 13.16 Thermal coal price fluctuations 2008–2018. Amsterdam, Rotterdam...
Guide
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Coal Geology
Third Edition
Larry ThomasRadcliffe House51, Monmouth RoadAbergavennyUK, NP7 5HP
This Third edition first published 2020
© 2020 John Wiley & Sons Ltd.
Wiley-Blackwell; 2 edition (November 5, 2012) 9781119990444
Wiley India , First Edition 9788126533008
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Library of Congress Cataloging-in-Publication Data
Names: Thomas, Larry (Larry P.), author.
Title: Coal geology / Larry Thomas.
Description: Third edition. | Hoboken, NJ : Wiley, 2020. | Includes index.
Identifiers: LCCN 2020001898 (print) | LCCN 2020001899 (ebook) | ISBN
9781119424130 (hardback) | ISBN 9781119424123 (adobe pdf) | ISBN
9781119424260 (epub)
Subjects: LCSH: Coal–Geology.
Classification: LCC TN802 .T47 2020 (print) | LCC TN802 (ebook) | DDC
553.2/4–dc23
LC record available at https://lccn.loc.gov/2020001898
LC ebook record available at https://lccn.loc.gov/2020001899
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Cover Image: © EvgenyMiroshnichenko/iStock.com
Preface to Third Edition
The first and second editions of Coal Geology have provided the coal geologist and those associated with the coal industry with the background to the origins and characteristics of coal together with exploration techniques, including geophysics and hydrogeology. Details of coalmining techniques, resource calculations, alternative uses of coal, and environmental issues were also described.
Although broadly following the layout of the previous edition, additional information has been added to coal origins, geographical distribution of coal, and coal exploration. The chapter on coal resources and reserves has been updated with current resource classifications, together with recent world reserves/production figures.
The chapter on the alternative uses of coal, particularly coal‐bed and coalmine methane extraction, have been expanded to reflect the increase in activity in these areas. Developments in environmental requirements and regulations have also been updated.
Again, numerous sources of information have been consulted, the majority of which are listed in the bibliography section. International standards relating to coal, listed in Appendix A, have been updated and expanded to include the People's Republic of China, India, and Russia, and a list of acronyms has been added to assist the reader.
I would like to thank all those colleagues and friends who have helped and encouraged me with the third edition. In particular, special thanks are due to Steve Frankland of Dargo Associates Ltd, Dr Gareth George for his expertise on sedimentary sequences, Rob Evans for his help with coal geophysics, and to the following for their contributions and support: Professor Vladimir Pavlovic, Dr Dave Pearson of Pearson Coal Petrography and Argus Media Ltd, as well as the staff at John Wiley & Sons Ltd.
I also thank those authors and organisations who gave permission to reproduce their work, which is gratefully acknowledged.
Finally, I would like to thank my wife Sue for her continued support, forbearance, and assistance with the manuscript.
Preface to Second Edition
The first edition of Coal Geology has provided the coal geologist and those associated with the coal industry with the background to the origins and characteristics of coal together with exploration techniques including geophysics and hydrogeology. Details of coal mining techniques, resource calculations, alternative uses of coal and environmental issues were also described.
Although broadly following the layout of the first edition, additional information has been added to coal origins, geographical distribution of coal and coal exploration. The chapter on coal resources and reserves has been brought up to date with current resource classifications together with recent world reserves/production figures.
The chapter on geophysics of coal has been enlarged and the alternative uses of coal, in particular, methane extraction and underground coal gasification have been expanded to reflect the increase in activity in these areas. Developments in environmental requirements have also been updated.
Again, numerous sources of information have been consulted, the majority of which are listed in the bibliography section. International Standards relating to coal, listed in Appendix 1, have been updated and expanded to include P R China, India and Russia.
I would like to thank all those colleagues and friends who have helped and encouraged me with the second edition. In particular, special thanks are due to Steve Frankland of Dargo Associates Ltd, Rob Evans for his invaluable help with coal geophysics, Paul Ahner in the U.S.A. for providing data on underground coal gasification, and to the following for their contributions and support, Professor Vladimir Pavlovic of Belgrade University, Mike Coultas, Dave Pearson of Pearson Coal Petrography, Oracle Coalfields plc and Robertson Geologging, as well as the staff at John Wiley & Sons Ltd.
I also thank those authors and organisations whose permission to reproduce their work is gratefully acknowledged.
Finally I would like to thank my wife Sue for her support, forbearance and assistance with the manuscript.
Preface to First Edition
The Handbook of Practical Coal Geology (Thomas 1992) was intended as a basic guide for coal geologists to use in their everyday duties, whether on site, in the office or instructing others. It was not intended as a definitive work on all or any particular aspect of coal geology, rather as a handbook to use as a precursor to, or in conjunction with more specific and detailed works.
This new volume is designed to give both the coal geologist and others associated with the coal industry background information regarding the chemical and physical properties of coal, its likely origins, its classification and current terminology. In addition I have highlighted the currently known geographical distribution of coal deposits together with recent estimates of world resources and production. I have also outlined the exploration techniques employed in the search for, and development of these coal deposits and the geophysical and hydrogeological characteristics of coal‐bearing sequences, together with the calculation and categorisation of resources/reserves.
Chapters are devoted to the mining of coal, to the means of extracting energy from coal other than by conventional mining techniques, and to the environmental concerns associated with the mining and utilisation of coal.
Also covered is the development of computer technology in the geological and mining fields, and the final chapter is a condensed account of the marketing of coal, its uses, transportation and price.
Many sources of information have been consulted, the majority of which are listed in the reference section. A set of appendices contains information of use to the reader.
I would like to thank all those colleagues and friends who have helped and encouraged me with the book from conception to completion. In particular special thanks are due to Steve and Ghislaine Frankland of Dargo Associates Ltd, Alan Oakes, Rob Evans, Dr Keith Ball, Professor Brian Williams, Mike Coultas, Reeves Oilfield Services, IMC Geophysics Ltd and Palladian Publications, as well as the staff at John Wiley & Sons Ltd.
I should also like to thank those authors and organisations whose permission to reproduce their work is gratefully acknowledged.
Finally I would like to thank my family for their support, encouragement and assistance with the manuscript.
Larry Thomas
List of Acronyms
AMD
Acid mine drainage
AMM
Abandoned‐mine methane
ASTM
American Society for Testing and Materials
BAP
Bali Action Plan
BFBC
Bubbling fluidised‐bed combustion
BOF
Basic oxygen furnace
CBM
Coal‐bed methane
CCS
Carbon capture and storage
CDM
Clean development mechanism
CFBC
Circulating fluidised‐bed combustion
CFR
Code of Federal Regulations
CHP
Combined heat and power
CIM
Canadian Institute for Mining, Metallurgy and Petroleum
CMM
Coalmine methane
CMMI
Council of Mining & Metallurgical Institutions
CRIRSCO
Committee for Mineral Reserves International Reporting Standards
CSG
Coal seam gas
EAF
Electric arc furnace
EFG
European Federation of Geologists
EISA
Environmental Impact and Social Assessment
EPA
Environmental Protection Agency
FBC
Fluidised‐bed combustion
FCCC
Framework Convention on Climate Change
FGD
Flue gas desulfurisation
GHG
Greenhouse gas
IGCC
Integrated gasification combined cycle
ISP
Indian Standard Procedure
JORC
Joint Ore Reserves Committee
LRTAP
Long‐range trans‐boundary air pollution
NAEN
Russian Code for Public Reporting of Exploration Results, Mineral Resources & Reserves
NDC
Nationally determined contribution
NRO
National Reporting Organisation
PCDDs
Polychlorinated dibenzo‐
para
‐dioxins
PCDFs
Polychlorinated dibenzofurans
PERC
Pan‐European Reserves and Resources Reporting Committee
PM
Particulate matter
PRC
People's Republic of China
R/P
Reserves/production ratio
SAMREC
South African Code for Reporting of Exploration Results, Mineral Resources and Reserves
SAMVAL
South African Code for Reporting of Mineral Asset Valuation
SCR
Selective catalytic reduction
SEC
United States Securities and Exchange Commission
SME
Society for Mining, Metallurgy and Exploration (USA)
TDS
Total dissolved solids
TEO
Technical–economic justification
TERI
The Energy Research Institute (India)
UCG
Underground coal gasification
UNECE
United Nations Economic Commission for Europe
UNEP
United Nations Environment Programme
UNFC
United Nations Framework Classification for Fossil Energy and Mineral Resources
UNFCCC
United Nations Convention on Climate Change
USGS
United States Geological Survey
VALMIN
Australian Code for the Public Reporting of Technical Assessments and Valuations of Mineral Assets
VAM
Ventilation air methane
WCA
World Coal Association
WEC
World Energy Council
1Preview
1.1 Scope
The object of this book remains unchanged. It is to provide geologists and those associated with the coal industry, as well as teachers of courses on coal about its geology and uses, with a background of the nature of coal and its varying properties, together with the practice and techniques required in order to compile geological data that will enable a coal sequence under investigation to be ultimately evaluated in terms of mineability and saleability. In addition, the alternative uses of coal as a source of energy together with the environmental implications of coal usage are also addressed.
Each of these subjects is a major topic in itself, and the book only covers a brief review of each, highlighting the relationship between geology and the development and commercial exploitation of coal.
1.2 Coal Geology
Coal is a unique rock type in the geological column. It has a wide range of chemical and physical properties, and it has been studied over a long period of time. This volume is intended to be a basic guide to understanding the variation in coals and their modes of origin and of the techniques required to evaluate coal occurrences.
The episodes of coal development in the geological column are given together with the principal coal occurrences worldwide. It is accepted that this is not totally exhaustive, as coal does occur in small areas not indicated in the figures or tables.
The reporting of coal resources/reserves is an important aspect of coal geology, and international standards and guidelines are in place to ensure the correct reporting procedures to be undertaken. Most national standards are now being reconciled with these, and the principal resources/reserves classifications are given. Current estimates of global resources and reserves of coal, together with coal production figures, are listed. Although these obviously become dated, they do serve to indicate where the major deposits and mining activities are currently concentrated.
In relation to the extraction of coal, the understanding of the geophysical and hydrogeological properties of coals is an integral part of any coalmine development, and these are reviewed together with the principal methods of mining coal. The increasing use of computer technology has had a profound impact on geological and mining studies. Some of the applications of computers to these are discussed.
An important development in recent years has been the attempts to use coal as an alternative energy source by either removing methane (CH4) gas from the in‐situ coal and coal mines, or by liquefying the coal as a direct fuel source, or by gasification of coal in situ underground. These technologies together are particularly significant in areas where conventional coalmining has ceased or where coal deposits are situated either at depths uneconomic to mine or in areas where mining is considered environmentally undesirable.
1.3 Coal Use
The principal uses of traded coals worldwide are for electricity generation and steel manufacture, with other industrial users and domestic consumption making up the remainder.
Lack of environmental controls in the use of coal in the past has led to both land and air pollution, as well as destruction of habitat. Modern environmental guidelines and legislation are both repairing the damage of the past and preventing a reoccurrence of such phenomena. An outline is given of the types of environmental concerns that exist where coal is utilised, together with the current position on the improvements in technology in mining techniques, industrial processes, and electricity generation emissions.
The marketing of coal is outlined, together with the contractual and pricing mechanisms commonly employed in the coal producer/coal user situation.
1.4 Background
In most industrial countries, coal has historically been a key source of energy and a major contributor to economic growth. In today's choice of alternative sources of energy, industrialised economies have seen a change in the role for coal.
Originally, coal was used as a source of heat and power in homes and industry. During the 1950s and 1960s cheap oil curtailed the growth of coal use, but the uncertainties of oil supply in the 1970s led to a resumption in coal consumption and a rapid growth in international coal trade. This, in turn, was followed by an increasingly unfavourable image for coal as a contributor to greenhouse gas (GHG) emissions and had been closely identified with global warming. The coal industry has responded positively to this accusation, and modern industrial plants have much lower emissions levels than in previous years. Current figures show that coal accounts for 45% of all carbon dioxide (CO2) emissions.
The world consumption of fossil fuels, and thus emissions of CO2, will continue to increase, and fossil fuels still meet around 86% of primary energy requirements. The objective of the United Nations Framework Convention on Climate Change (UNFCCC) signed at the 1992 Earth Summit in Rio de Janeiro is to ‘stabilise GHG concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system’. No set levels were identified, but emissions in developed countries were expected to be reduced to 1990 levels. A series of annual meetings by the international body under the UNFCCC, the Conference of the Parties (COP), have taken place, notably COP‐3 in Kyoto, Japan, in 1997, at which the Kyoto Protocol was drawn up, setting emissions targets for all the countries attending. However, government ministers at COP‐6 in The Hague in November 2000 failed to agree on the way forward to meet the Kyoto Protocol targets. This placed the whole of the Kyoto Protocol's ambitious and optimistic plan for a global agreement on GHG emissions reduction in an uncertain position. This could be an indication of overambitious goals rather than any failure in the negotiations, and it is up to the parties concerned to establish a realistic set of targets for emissions reductions in the future. The Copenhagen Accord in 2009 reinforced the need for emissions reductions, together with providing financial assistance to help developing countries cut carbon emissions. In 2015, at the Paris Agreement, parties to the UNFCCC reached agreement to combat climate change and to accelerate and intensify the actions and investments for a sustainable low‐carbon future. This was the first legally binding global climate deal.
It remains a fact that many economies still depend on coal for a significant portion of their energy needs. Coal currently accounts for 28% of the world's consumption of primary energy, and, importantly, coal provides fuel for the generation of around 39% of the total of the world's electricity. In 2018, internationally traded coal was 1169 Mt, the bulk of which was steam or thermal coal. Globally, 5.6 Gt of coal was consumed in 2016 (BP plc 2017).
Coal reserves are currently estimated to be around 900 Gt, and the world coal reserves to production ratio is nearly six times that for oil and four times that for natural gas. This, together with the globally democratic distribution and secure nature of coal deposits, will ensure that coal will continue to be a major energy resource for some considerable time to come.
With this scenario in mind, this volume is intended to assist those associated with the coal industry, as well as educationalists and those required to make economic and legislative decisions about coal.
The philosophy and views expressed in this book are those of the author and not the publisher.
2Origin of Coal
2.1 Introduction
Sedimentary sequences containing coal or peat beds are found throughout the world and range in age from middle Palaeozoic to Recent.
Coals are the result of the accumulation of vegetable debris in a specialised environment of deposition. Such accumulations have been affected by synsedimentary and post‐sedimentary influences to produce coals of differing rank and differing degrees of structural complexity, the two being closely interlinked. The plant types that make up coals have evolved over geological time, providing a variety of lithotypes in coals of differing ages.
Remarkable similarities exist in coal‐bearing sequences, due for the greater part to the particular sedimentary associations required to generate and preserve coals. Sequences of vastly different ages from areas geographically separate have a similar lithological framework and can react in similar fashions structurally.
It is a fact, however, that the origin of coal has been studied for over a century and that no one model has been identified that can predict the occurrence, development, and type of coal. A variety of models exist that attempt to identify the environment of deposition, but no single one can adequately give a satisfactory explanation for the cyclic nature of coal sequences, the lateral continuity of coal beds, and the physical and chemical characteristics of coals. However, the advent of sequence stratigraphy has recognised the pattern of geological events leading to the different phases of deposition and erosion within coal‐bearing sequences.
2.2 Sedimentation of Coal and Coal‐Bearing Sequences
During the last 90 years, interest has grown rapidly in the study of sedimentological processes, particularly those characteristic of fluviatile and deltaic environments. It is these, in particular, that have been closely identified with coal‐bearing sequences.
It is important to give consideration both to the recognition of the principal environments of deposition and to the recent changes in emphasis regarding those physical processes required, in order to produce coals of economic value. In addition, the understanding of the shape, morphology, and quality of coal seams is of fundamental significance for the future planning and mining of coals. Although the genesis of coal has been the subject of numerous studies, models that are used to determine the occurrence, distribution, and quality of coal are often still too imprecise to allow such accurate predictions.
2.2.1 Depositional Models
The recognition of depositional models to explain the origin of coal‐bearing sequences and their relationship to surrounding sediments has been achieved by a comparison of the environments under which modern peats are formed and ancient sequences containing coals.
Cecil et al. (1993) suggested that the current models often concentrate on the physical description of the sediments associated with coal rather than concentrating on the geological factors that control the genesis of coal beds. They also suggest that models that combine sedimentation and tectonics with eustasy and chemical change have not yet been fully developed. Such integrated models would give an improved explanation of physical and chemical processes of sedimentation. It should be noted that the use of sequence stratigraphy in facies modelling is based on physical processes and does not take into account chemical stratigraphy. This will prove a deficiency when predicting the occurrence and character of coal beds.
The traditional depositional model used by numerous workers was based on the ‘cyclothem’, a series of lithotypes occurring in repeated ‘cycles’. Weller (1930) and Wanless and Weller (1932) remarked on the similarity of stratigraphic sections associated with every coal bed; i.e. marine sediments consisted of black sheety shale with large concretions, limestone with marine fossils and shale with ironstone nodules and bands, whereas continental sequences comprised sandstone lying unconformably on lower beds, sandy shale, limestone without marine fossils, rootlet bed or seatearth, and then coal. Although all of the members of each cyclothem vary in thickness and lithology from place to place, the character of some beds is remarkably similar at localities great distances apart. Their studies showed that the entire Pennsylvanian (upper Carboniferous) system in the Eastern Interior and northern Appalachian Basins and the Lower Pennsylvanian strata in the northern part of the Western Interior Basin consist of similar successions of cyclothems. Individual cyclothems are persistent, and correlation of cyclothems at widely separated localities is possible. This concept has been modified to a model that relates lateral and vertical sequential changes to depositional settings that have been recognised in modern fluvial, deltaic, and coastal barrier systems. Further studies on the traditional model are based on work carried out in the USA by Horne (1979), Horne et al. (1978, 1979), Ferm (1979), Ferm et al. (1979), Ferm and Staub (1984), and Staub and Cohen (1979). The sequences, or lithofacies, are characterised by the sedimentary features listed in Table 2.1. Other workers include Thornton (1979) and Jones and Hutton (1984) on coal sequences in Australia, Galloway and Hobday (1996), and Guion et al. (1995) and George (2014) in the UK. More recent studies have compared such established depositional models with modern coastal plain sedimentation, e.g. in equatorial South‐East Asia, and have concentrated in particular on modern tropical peat deposits (Cecil et al. 1993; Clymo 1987; Gastaldo et al. 1993; McCabe and Parrish 1992). Studies by Hobday (1987), Diessel (1992), Lawrence (1992), Jerzykiewicz (1992), Dreesen et al. (1995), Cohen and Spackman (1972, 1980), Flint et al. (1995), and McCabe (1984, 1987, 1991) have all further developed the model for coal deposits of differing ages, using the traditional model but relating it to modern sedimentary processes. Galloway and Hobday (1996), in their textbook, give a detailed analysis of coal‐bearing environments with worldwide examples.
Table 2.1 Sedimentary features used to identify depositional environments.
Source: From Horne et al. (1979).
Recognition characteristics
Fluvial and upper delta plain
a
Transitional lower delta plain
a
Lower delta plain
a
Back‐barrier
a
Barrier
a
I Coarsening upwards
A Shale and siltstone sequences
2–3
2
1
2–1
3–2
(i) >50 ft
4
3–4
2–1
2–1
3–2
(ii) 5–25 ft
2–3
2–1
2–1
2–1
3–2
B Sandstone sequences
3–4
3–2
2–1
2
2–1
(i) >50 ft
4
4
2–1
3
2–1
(ii) 5–25 ft
3
3–2
2–1
2
2
II Channel deposits
A Fine‐grained abandoned fill
3
2–3
1–2
2
3–2
(i) Clay and silt
3
2–3
1–2
2
3–2
(ii)Organic debris
3
2–3
1–2
2–3
3
B Active sandstone fill
1
2
2–3
2–3
2
(i)Fine grained
2
2
2–3
2–3
2
(ii)Medium‐ and coarse‐grained
1
2–3
3
3
2–3
(iii)Pebble lags
1
1
2
2–3
3–2
(iv) Coal spars
1
1
2
2–3
3–2
III Contacts
A Abrupt (scour)
1
1
2
2
2–1
B Gradational
2–3
2
2–1
2
2
IV Bedding
A Cross beds
1
1
1
1–2
1–2
(i) Ripples
2
2–1
1
1
1
(ii) Ripple drift
2–1
2
2–3
3–2
3–2
(iii) Trough cross beds
1
1–2
2–1
2
2–1
(iv) Graded beds
3
3
2–1
3–2
3–2
(v) Point bar accretion
1
2
3–4
3–4
3–4
(vi) Irregular bedding
1
2
3–2
3–2
3–2
V Levee deposits
A Irregularly interbedded sandstones and shales, rooted
1
1–2
3–2
3
4
VI Mineralogy of sandstones
A Lithic greywacke
1
1
1–2
3
3
B Orthoquartzite
4
4
4–3
1–2
1
VII Fossils
A Marine
4
3–2
2–1
1–2
1–2
B Brackish
3
2
2
2–3
2–3
C Fresh
2–3
3–2
3–4
4
4
D Burrow
3
2
1
1
1
a 1, abundant; 2, common; 3, rare; 4, not present.
In parallel with this work, detailed studies of peat mires have both raised and answered questions on the development of coal geometry, i.e. thickness and lateral extent, together with the resultant coal chemistry.
The traditional model is still a basis for modern coal studies, but linked to detailed interpretation of sedimentary sequences and a better understanding of peat development and preservation.
