   #copyright

Coal

2007 Schools Wikipedia Selection. Related subjects: Environment; Mineralogy

   Coal
   Enlarge
   Coal

   Coal ( IPA: /ˈkəʊl/) is a fossil fuel extracted from the ground by
   underground mining or open-pit mining ( surface mining). It is a
   readily combustible black or brownish-black sedimentary rock. It is
   composed primarily of carbon along with assorted other elements,
   including sulfur. Often associated with the Industrial Revolution, coal
   remains an enormously important fuel. It is the largest single source
   of fuel for the generation of electricity world-wide, and a vital
   component in the reduction of iron ore.

Early usage

   Outcrop coal was used in Britain during the Bronze Age (2-3000 years
   BCE), where it has been detected as forming part of the composition of
   funeral pyres. It was also commonly used in the early period of the
   Roman occupation. Evidence of trade in coal (dated to about 200 CE) has
   been found at the inland port of Heronbridge, near Chester, and in the
   Fenlands of East Anglia, where coal from the Midlands was transported
   via the Car Dyke for use in drying grain. Coal cinders have been found
   in the hearths of villas and military forts, particularly in
   Northumberland, dated to around 400 CE. In the west of England
   contemporary writers described the wonder of a permanent brazier of
   coal on the altar of Minerva at Aquae Sulis (modern day Bath) although
   in fact easily-accessible surface coal from what is now the Somerset
   coalfield was in common use in quite lowly dwellings locally.

   However, there is no evidence that the product was of great importance
   in Britain before the High Middle Ages, after about 1000 CE. Mineral
   coal came to be referred to as "seacoal," probably because it came to
   many places in eastern England, including London, by sea. This is
   accepted as the more likely explanation for the name than that it was
   found on beaches, having fallen from the exposed coal seams above or
   washed out of underwater coal seam outcrops. These easily accessible
   sources had largely become exhausted (or could not meet the growing
   demand) by the 13th century, when underground mining from shafts or
   adits was developed. In London there is still a Seacoal Lane (off the
   north side of Ludgate Hill) where the coal merchants used to conduct
   their business. An alternative name was "pitcoal," because it came from
   mines.

Etymology and folklore

   The term originates from the Anglo-Saxon word col " charcoal" and is
   related to a common Germanic root of otherwise unclear origins.

   It is associated with the astrological sign Capricorn and is carried by
   thieves to protect them from detection and to help them to escape when
   pursued. It is an element of a popular ritual associated with New
   Year's Eve. To dream of burning coals is a symbol of disappointment,
   trouble, affliction, and loss, unless they are burning brightly, when
   the symbol gives promise of uplifting and advancement.

   In Anglo-Saxon countries, Santa Claus is said to leave a lump of coal
   instead of Christmas presents in the stockings of naughty children.

   In Scotland coal is brought to a household as a symbolic gift in the
   Hogmanay ritual of first-footing.

Composition

   Carbon forms more than 50 percent by weight and more than 70 percent by
   volume of coal (this includes inherent moisture). This is dependent on
   coal rank, with higher rank coals containing less hydrogen, oxygen and
   nitrogen, until 95% purity of carbon is achieved at Anthracite rank and
   above. Graphite formed from coal is the end-product of the thermal and
   diagenetic conversion of plant matter (50% by volume of water) into
   pure carbon.

   Coal usually contains a considerable amount of incidental moisture,
   which is the water trapped within the coal in between the coal
   particles. Coals are usually mined wet and may be stored wet to prevent
   spontaneous combustion, so the carbon content of coal is quoted as both
   a 'as mined' and on a 'moisture free' basis.

   Lignite and other low-rank coals still contain a considerable amount of
   water and other volatile components trapped within the particles of the
   coal, known as its macerals. This is present either within the coal
   particles, or as hydrogen and oxygen atoms within the molecules. This
   is because coal is converted from carbohydrate material such as
   cellulose, into carbon, which is an incremental process (see below).
   Therefore coal carbon contents also depend heavily on the degree to
   which this cellulose component is preserved in the coal.

   Other constituents of coals include mineral matter, usually as silicate
   minerals such as clays, illite, kaolinite and so forth, as well as
   carbonate minerals like siderite, calcite and aragonite. Iron sulfide
   minerals such as pyrite are common constituents of coals. Sulfate
   minerals are also found, as is some form of salt, trace amounts of
   metals, notably iron, uranium, cadmium, and (rarely) gold.

   Methane gas is another component of coal, produced from methanogenesis.
   Methane in coal is dangerous, as it can cause coal seam explosions,
   especially in underground mines, and may cause the coal to
   spontaneously combust. It is, however, a valuable by-product of some
   coal mining, serving as a significant source of natural gas.

   Coal composition is determined by specific coal assay techniques, and
   is performed to quantify the physical, chemical and mechanical
   behaviour of the coal, including whether it is a good candidate for
   coking coal.

   Some of the macerals of coal are:-
     * vitrinite: fossil woody tissue, likely often charcoal from forest
       fires in the coal forests
     * fusinite: made from peat made from cortical tissue
     * exinite: fossil spore casings and plant cuticles
     * resinite: fossil resin and wax
     * alginite: fossil algal material

Origin of coal

   Dicrhodium fern fossils in drill core, Surat Basin, Queensland from
   silt parting in coal beds. Fossilised plant material implies this coal
   formed around plants.
   Enlarge
   Dicrhodium fern fossils in drill core, Surat Basin, Queensland from
   silt parting in coal beds. Fossilised plant material implies this coal
   formed around plants.

   Coal is formed from plant remains that have been compacted, hardened,
   chemically altered, and metamorphosed by heat and pressure over
   geologic time.

   Coal was formed in swamp ecosystems which persisted in lowland
   sedimentary basins similar, for instance, to the peat swamps of Borneo
   today. These swamp environments were formed during slow subsidence of
   passive continental margins, and most seem to have formed adjacent to
   estuarine and marine sediments suggesting that they may have been in
   tidal delta environments. They are often called the " coal forests".

   When plants die in these peat swamp environments, their biomass is
   deposited in anaerobic aquatic environments where low oxygen levels
   prevent their complete decay by bacteria and oxidation. For masses of
   undecayed organic matter to be preserved and to form economically
   valuable coal the environment must remain steady for prolonged periods
   of time, and the waters feeding these peat swamps must remain
   essentially free of sediment. This requires minimal erosion in the
   uplands of the rivers which feed the coal swamps, and efficient
   trapping of the sediments.

   Eventually, and usually due to the initial onset of orogeny or other
   tectonic events, the coal forming environment ceases. In the majority
   of cases this is abrupt, with the majority of coal seams having a
   knife-sharp upper contact with the overlying sediments. This suggests
   that the onset of further sedimentation quickly destroys the peat swamp
   ecosystem and replaces it with meandering stream and river environments
   during ongoing subsidence.

   Burial by sedimentary loading on top of the peat swamp converts the
   organic matter to coal by the following processes;
     * compaction, due to loading of the sediments on the coal which
       flattens the organic matter
     * removal of the water held within the peat in between the plant
       fragments
     * with ongoing compaction, removal of water from the inter-cellular
       structure of fossilised plants
     * with heat and compaction, removal of molecular water
     * methanogenesis; similar to treating wood in a pressure cooker,
       methane is produced, which removes hydrogen and some carbon, and
       some further oxygen (as water)
     * dehydrogenation, which removes hydroxyl groups from the cellulose
       and other plant molecules, resulting in the production of
       hydrogen-reduced coals

   Generally, to form a coal seam 1 metre thick, between 10 and 30 metres
   of peat is required. Peat has a moisture content of up to 90%, so loss
   of water is of prime importance in the conversion of peat into lignite,
   the lowest rank of coal. Lignite is then converted by dehydrogenation
   and methanogenesis to sub-bituminous coal. Further dehydrogenation
   reactions, removing progressively more methane and higher hydrocarbon
   gases such as ethane, propane, etcetera, create bituminous coal and,
   when this process is complete at sub-metamorphic conditions, anthracite
   and graphite are formed.
   Dichrodium fern fossils from coal beds, Queensland. Coal essentially
   always includes fossil imprints such as these, revealing its organic
   origin.
   Enlarge
   Dichrodium fern fossils from coal beds, Queensland. Coal essentially
   always includes fossil imprints such as these, revealing its organic
   origin.

   Evidence of the types of plants that contributed to carbonaceous
   deposits can occasionally be found in the shale and sandstone sediments
   that overlie coal deposits and within the coal. Fossil evidence is best
   preserved in lignites and sub-bituminous coals, though fossils in
   anthracite are not too rare. To date only three fossils have been found
   in graphite seams created from coal.

   The greatest coal-forming time in geologic history was during the
   Carboniferous era (280 to 345 million years ago). Further large
   deposits of coal are found in the Permian, with lesser but still
   significant Triassic and Jurassic deposits, and minor Cretaceous and
   younger deposits of lignite. In the modern European lowlands of Holland
   and Germany considerable thicknesses of peat have accumulated,
   testifying to the ubiquity of the coal-forming process.

   In Europe, Asia, and North America, the Carboniferous coal was formed
   from tropical swamp forests, which are sometimes called the "coal
   forests". Southern hemisphere Carboniferous coal was formed from the
   Glossopteris flora, which grew on cold periglacial tundra when the
   South Pole was a long way inland in Gondwanaland.

Types of coal

   As geological processes apply pressure to peat over time, it is
   transformed successively into:
     * Lignite - also referred to as brown coal, is the lowest rank of
       coal and used almost exclusively as fuel for steam-electric power
       generation. Jet is a compact form of lignite that is sometimes
       polished and has been used as an ornamental stone since the Iron
       Age.
     * Sub-bituminous coal - whose properties range from those of lignite
       to those of bituminous coal and are used primarily as fuel for
       steam-electric power generation.
     * Bituminous coal - a dense coal, usually black, sometimes dark
       brown, often with well-defined bands of bright and dull material,
       used primarily as fuel in steam-electric power generation, with
       substantial quantities also used for heat and power applications in
       manufacturing and to make coke.
     * Anthracite - the highest rank; a harder, glossy, black coal used
       primarily for residential and commercial space heating.

Uses

   Coal rail cars in Ashtabula, Ohio.
   Enlarge
   Coal rail cars in Ashtabula, Ohio.

Coal as fuel

   Coal is primarily used as a solid fuel to produce electricity and heat
   through combustion. World coal consumption is about 5,800 million short
   tons (5.3 petagrams) annually, of which about 75% is used for the
   production of electricity . The region including the People's Republic
   of China and India uses about 1,700 long tons (1.5 Pg) annually,
   forecast to exceed 3,000 million short tons (2.7 Pg) in 2025. The USA
   consumes about 1,100 million short tons (1.0 Pg) of coal each year,
   using 90% of it for generation of electricity. Coal is the fastest
   growing energy source in the world, with coal use increasing by 25% for
   the three-year period ending in December 2004 (BP Statistical Energy
   Review, June 2005).

   When coal is used for electricity generation, it is usually pulverized
   and then burned in a furnace with a boiler. The furnace heat converts
   boiler water to steam, which is then used to spin turbines which turn
   generators and create electricity. The thermodynamic efficiency of this
   process has been improved over time. "Standard" steam turbines have
   topped out with about 35–40% thermodynamic efficiency for the entire
   process, but the emergence of supercritical turbines running at
   extremely high temperatures and pressures has led to efficiencies of
   46%, with further increases in temperature and pressure offering
   potential for even higher efficiencies Approximately 40% of the world
   electricity production uses coal, and the total known deposits
   recoverable by current technologies are sufficient for 300 years' use
   at current usage levels, although maximal production could be reached
   within decades (see World Coal Reserves, below).

   A promising, more energy-efficient way of using coal for electricity
   production would be via solid-oxide fuel cells or molten-carbonate fuel
   cells (or any oxygen ion transport based fuel cells that do not
   discriminate between fuels, as long as they consume oxygen), which
   would be able to get 60%–85% combined efficiency (direct electricity +
   waste heat steam turbine). Currently these fuel cell technologies can
   only process gaseous fuels, and they are also sensitive to sulfur
   poisoning, issues which would first have to be worked out before large
   scale commercial success is possible with coal. As far as gaseous fuels
   go, one idea is pulverized coal in a gas carrier, such as nitrogen.
   Another option is coal gasification with water, which may lower fuel
   cell voltage by introducing oxygen to the fuel side of the electrolyte,
   but may also greatly simplify carbon sequestration.

Coking and use of coke

   Coke is a solid carbonaceous residue derived from low-ash, low-sulfur
   bituminous coal from which the volatile constituents are driven off by
   baking in an oven without oxygen at temperatures as high as 1,000 °C
   (1,832 °F) so that the fixed carbon and residual ash are fused
   together. Coke is used as a fuel and as a reducing agent in smelting
   iron ore in a blast furnace. Coke from coal is grey, hard, and porous
   and has a heating value of 24.8 million Btu/ton (29.6 MJ/kg).
   Byproducts of this conversion of coal to coke include coal tar,
   ammonia, light oils, and " coal-gas".

   Petroleum coke is the solid residue obtained in oil refining, which
   resembles coke but contains too many impurities to be useful in
   metallurgical applications.

Gasification

   High prices of oil and natural gas are leading to increased interest in
   "BTU Conversion" technologies such as coal gasification, methanation
   and liquification.

   Coal gasification breaks down the coal into its components, usually by
   subjecting it to high temperature and pressure, using steam and
   measured amounts of oxygen. This leads to the production of carbon
   dioxide and oxygen, as well as other gaseous compounds.

   In the past, coal was converted to make coal gas, which was piped to
   customers to burn for illumination, heating, and cooking. At present,
   the safer natural gas is used instead. South Africa still uses
   gasification of coal for much of its petrochemical needs.

   Gasification is also a possibility for future energy use, as it
   generally burns hotter and cleaner than conventional coal and can thus
   spin a more efficient gas turbine rather than a steam turbine. It also
   makes for the possibility of zero carbon dioxide emissions even though
   the energy comes from the conversion of carbon to carbon dioxide. This
   is because gasification produces a much higher concentration of carbon
   dioxide than direct combustion of coal in air (which is mostly
   nitrogen). The higher concentrations of carbon dioxide makes carbon
   capture and storage more economical than it otherwise would be.

Liquefaction

   Coal can also be converted into liquid fuels like gasoline or diesel by
   several different processes. The Fischer-Tropsch process of indirect
   synthesis of liquid hydrocarbons was used in Nazi Germany for many
   years and is today used by Sasol in South Africa — in both cases
   because those regimes were politically isolated and unable to purchase
   crude oil on the open market. Coal would be gasified to make syngas (a
   balanced purified mixture of CO and H[2] gas) and the syngas condensed
   using Fischer-Tropsch catalysts to make light hydrocarbons which are
   further processed into gasoline and diesel. Syngas can also be
   converted to methanol, which can be used as a fuel, fuel additive, or
   further processed into gasoline via the Mobil M-gas process.

   A direct liquefaction process Bergius process (liquefaction by
   hydrogenation) is also available but has not been used outside Germany,
   where such processes were operated both during World War I and World
   War II. SASOL in South Africa has experimented with direct
   hydrogenation. Several other direct liquefaction processes have been
   developed, among these being the SRC-I and SRC-II (Solvent Refined
   Coal) processes developed by Gulf Oil and implemented as pilot plants
   in the United States in the 1960's and 1970's.

   Another direct hydrogenation process was explored by the NUS
   Corporation in 1976 and patented by Wilburn C. Schroeder. The process
   involved dried, pulverized coal mixed with roughly 1wt% molybdenum
   catalysis. Hydrogenation occurred by use of high temperature and
   pressure synthesis gas produced in a separate gasifier. The process
   ultimately yielded a synthetic crude product, Naptha, a limited amount
   of C[3]/C[4] gas, light-medium weight liquids (C[5]-C[10]) suitable for
   use as fuels, small amounts of NH[3] and significant amounts of CO[2].

   Yet another process to manufacture liquid hydrocarbons from coal is low
   temperature carbonization (LTC). Coal is coked at temperatures between
   450 and 700 °C compared to 800 to 1000 °C for metallurgical coke. These
   temperatures optimize the production of coal tars richer in lighter
   hydrocarbons than normal coal tar. The coal tar is then further
   processed into fuels. The Karrick process was developed by Lewis C.
   Karrick, an oil shale technologist at the U.S. Bureau of Mines in the
   1920s.

   All of these liquid fuel production methods release carbon dioxide
   (CO[2]) in the conversion process, far more than is released in the
   extraction and refinement of liquid fuel production from petroleum. If
   these methods were adopted to replace declining petroleum supplies
   carbon dioxide emissions would be greatly increased on a global scale.
   For future liquefaction projects, Carbon dioxide sequestration is
   proposed to avoid releasing it into the atmosphere. As CO[2] is one of
   the process streams, sequestration is easier than from flue gases
   produced in combustion of coal with air, where CO[2] is diluted by
   nitrogen and other gases. Sequestration will, however, add to the cost.

   Coal liquefaction is one of the backstop technologies that could
   potentially limit escalation of oil prices and mitigate the effects of
   transportation energy shortage under peak oil. This is contingent on
   liquefaction production capacity becoming large enough to satiate the
   very large and growing demand for petroleum. Estimates of the cost of
   producing liquid fuels from coal suggest that domestic U.S. production
   of fuel from coal becomes cost-competitive with oil priced at around 35
   USD per barrel , (break-even cost). This price, while above historical
   averages, is well below current oil prices. This makes coal a viable
   financial alternative to oil for the time being, although production is
   not great enough to make synfuels viable on a large scale. .

   Among commercially mature technologies, advantage for indirect coal
   liquefaction over direct coal liquefaction are reported by Williams and
   Larson (2003). Estimates are reported for sites in China where
   break-even cost for coal liquefaction may be in the range between 25 to
   35 USD/barrel of oil.

Harmful effects of coal burning

   Combustion of coal, like any other compound containing carbon, produces
   carbon dioxide (CO[2]) and nitrogen oxides (NO[x]) along with varying
   amounts of sulfur dioxide (SO[2]) depending on where it was mined.
   Sulfur dioxide reacts with oxygen to form sulfur trioxide (SO[3]),
   which then reacts with water to form sulfuric acid. The sulfuric acid
   is returned to the Earth as acid rain.

   Emissions from coal-fired power plants represent the largest source of
   carbon dioxide emissions, which have been implicated as the primary
   cause of global warming. Coal mining and abandoned mines also emit
   methane, another cause of global warming. Since the carbon content of
   coal is much higher than oil, burning coal is a more serious threat to
   the stability of the global climate. Many other pollutants are present
   in coal power station emissions. A study commissioned by environmental
   groups claims that coal power plant emissions are responsible for tens
   of thousands of premature deaths annually in the United States alone.
   Modern power plants utilize a variety of techniques to limit the
   harmfulness of their waste products and improve the efficiency of
   burning, though these techniques are not subject to standard testing or
   regulation in the U.S. and are not widely implemented in some
   countries, as they add to the capital cost of the power plant. To
   eliminate CO[2] emissions from coal plants, carbon capture and storage
   has been proposed but has yet to be commercially used.

   Coal and coal waste products including fly ash, bottom ash, boiler
   slag, and flue gas desulferization contain many heavy metals, including
   arsenic, lead, mercury, nickel, vanadium, beryllium, cadmium, barium,
   chromium, copper, molybdenum, zinc, selenium and radium, which are
   dangerous if released into the environment. Coal also contains low
   levels of uranium, thorium, and other naturally-occurring radioactive
   isotopes whose release into the environment may lead to radioactive
   contamination. While these substances are trace impurities, enough coal
   is burned that significant amounts of these substances are released,
   paradoxically resulting in more radioactive waste than nuclear power
   plants.

   Due to its scientifically accepted connection with climate change , the
   world's reliance on coal as an energy source, and health concerns in
   areas with poor air pollution controls, The Economist recently labeled
   the burning of coal "Environmental Enemy No. 1."

Energy density

   The energy density of coal is roughly 24 Megajoules per kilogram. It is
   perhaps more useful to put this into another unit of energy,
   kilowatt-hours. This is the unit that electricity is most commonly sold
   in. In that case, the energy density of coal is 6.67 kW*hours/kg.

   One can put this information to use to figure out how much coal is
   needed to power things. For example, running one 100 Watt computer for
   one year requires this much electricity:

                (100 \ W) \times (1 \ year) \times \left( \frac{365 \
                days}{1 \ year} \right) \times \left( \frac{24 \ hours}{1
                \ day} \right) \times \left( \frac{1 \ kW}{1000 \ W}
                \right) = 876 \ \mathrm{kW*hours} .

   A typical Thermodynamic efficiency of coal power plants is about 30%.
   Of the 6.67 kW*hours of energy per kilogram of coal, about 30% of that
   can successfully be turned into electricity - the rest is waste heat.
   Coal power plants obtain ~2.3 kW*hours/kg of burned coal.

   Plugging in this information one finds how much coal must be burned to
   power a typical computer for one year:

                \frac{876 \ \mathrm{kW*hours}}{2.3 \ \mathrm{kW*hours/kg}}
                = 380 \ \mathrm{kg \ of \ coal} = 838 \ \mathrm{pounds \
                of \ coal} .

   It takes 838 pounds of coal to power a computer for one full year.

Coal fires

   There are hundreds of coal fires burning around the world. Those
   burning underground can be difficult to locate and many cannot be
   extinguished. Fires can cause the ground above to subside, combustion
   gases are dangerous to life, and breaking out to the surface can
   initiate surface wildfires. See also Mine fire.

   Coal seams can be set on fire by spontaneous combustion or contact with
   a mine fire or surface fire. A grass fire in a coal area can set dozens
   of coal seams on fire. Coal fires in China burn 120 million tons of
   coal a year, emitting 360 million metric tons of carbon dioxide. This
   amounts to 2-3% of the annual worldwide production of CO[2] from fossil
   fuels, or as much as emitted from all of the cars and light trucks in
   the United States.

   In Centralia, Pennsylvania (a borough located in the Coal Region of the
   United States) an exposed vein of coal ignited in 1962 due to a trash
   fire in the borough landfill, located in an abandoned anthracite strip
   mine pit. Attempts to extinguish the fire were unsuccessful, and it
   continues to burn underground to this day.

   The reddish siltstone rock that caps many ridges and buttes in the
   Powder River Basin ( Wyoming), and in western North Dakota is called
   porcelanite, which also may resemble the coal burning waste " clinker"
   or volcanic " scoria." Clinker is rock that has been fused by the
   natural burning of coal. In the case of the Powder River Basin
   approximately 27 to 54 billion metric tons of coal burned within the
   past three million years. Wild coal fires in the area were reported by
   the Lewis and Clark Expedition as well as explorers and settlers in the
   area.

   The Australian Burning Mountain was originally believed to be a
   volcano, but the smoke and ash comes from a coal fire which may have
   been burning for over 5,500 years.

World coal reserves

   US coal regions
   Enlarge
   US coal regions

   It has been estimated that, as of 1996, there is around one exagram (1
   × 10^15 kg or 1 trillion tonnes) of total coal reserves accessible
   using current mining technology, approximately half of it being hard
   coal. The energy value of all the world's coal is well over 100,000
   quadrillion Btu (100 zettajoules). There is probably enough coal to
   last for 300 years. However, this estimate assumes no rise in
   population, and no increased use of coal to attempt to compensate for
   the depletion of natural gas and petroleum. A recent (2003) study by
   scientist Gregson Vaux, which takes those factors into account,
   estimates that coal could peak in the United States as early as 2032,
   on average. "Peak" does not mean coal will disappear, but defines the
   time after which no matter what efforts are expended, coal production
   will begin to decline in quantity and energy content. The disappearance
   of coal will occur much later, around the year 2267, assuming all other
   factors do not change. British Petroleum, in its annual report 2006,
   estimated at 2005 end, there were 909,064 million tons of proved coal
   reserves worldwide, or 155 years reserve to production ratio.

   The United States Department of Energy uses estimates of coal reserves
   in the region of 1,081,279 million short tons, which is about 4,786
   BBOE (billion barrels of oil equivalent) . The amount of coal burned
   during 2001 was calculated as 2.337 GTOE (gigatonnes of oil
   equivalent), which is about 46 MBOED (million barrels of oil equivalent
   per day) . At that rate those reserves will last 285 years. As a
   comparison natural gas provided 51 MBOED, and oil 76 MBD (million
   barrels per day) during 2001.

   Of the 3 fossil fuels coal has the most widely distributed reserves,
   and coal is mined in over 100 countries, and on all continents except
   Antarctica. The largest reserves are found in the USA, Russia, China,
   Pakistan, India, Australia and South Africa.

   CAPTION: Proved recoverable coal reserves at end-1999 (million tonnes)

   Coutry Bituminous (including anthracite) Sub- bituminous Lignite TOTAL
             United States of America 115891 101021 33082 249994
                 Russian Federation 49088 97472 10450 157010
                       China 62200 33700 18600 114500
                           India 82396 2000 84396
                      Australia 42550 1840 37700 82090
                          Germany 23000 43000 66000
                          South Africa 49520 49520
                       Ukraine 16274 15946 1933 34153
                         Kazakhstan 31000 3000 34000
                           Poland 20300 1860 22160
                   Serbia, Montenegro 64 1460 14732 16256
                             Brazil 11929 11929
                           Colombia 6267 381 6648
                          Canada 3471 871 2236 6578
                      Czech Republic 2114 3414 150 5678
                        Indonesia 790 1430 3150 5370
                             Botswana 4300 4300
                          Uzbekistan 1000 3000 4000
                          Turkey 278 761 2650 3689
                              Greece 2874 2874
                          Bulgaria 13 233 2465 2711
                             Pakistan 2265 2265
                        Iran (Islamic Rep.) 1710 1710
                        United Kingdom 1000 500 1500
                           Romania 1 35 1421 1457
                             Thailand 1268 1268
                           Mexico 860 300 51 1211
                             Chile 31 1150 1181
                            Hungary 80 1017 1097
                              Peru 960 100 1060
                             Kyrgyzstan 812 812
                                Japan 773 773
                            Spain 200 400 60 660
                Korea (Democratic People's Rep.) 300 300 600
                         New Zealand 33 206 333 572
                              Zimbabwe 502 502
                             Netherlands 497 497
                              Venezuela 479 479
                              Argentina 430 430
                           Philippines 232 100 332
                             Slovenia 40 235 275
                             Mozambique 212 212
                              Swaziland 208 208
                              Tanzania 200 200
                             Nigeria 21 169 190
                              Greenland 183 183
                              Slovakia 172 172
                               Vietnam 150 150
                        Congo (Democratic Rep.) 88 88
                           Korea (Republic) 78 78
                                 Niger 70 70
                              Afghanistan 66 66
                                Algeria 40 40
                               Croatia 6 33 39
                              Portugal 3 33 36
                               France 22 14 36
                                Italy 27 7 34
                                Austria 25 25
                                Ecuador 24 24
                           Egypt (Arab Rep.) 22 22
                                Ireland 14 14
                                Zambia 10 10
                                Malaysia 4 4
                        Central African Republic 3 3
                             Myanmar (Burma) 2 2
                                 Malawi 2 2
                              New Caledonia 2 2
                                  Nepal 2 2
                                 Bolivia 1 1
                                 Norway 1 1
                        Taiwan(Republic Of China) 1 1
                                 Sweden 1 1

   Retrieved from " http://en.wikipedia.org/wiki/Coal"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
