Coal fire

Detailed view of a column over a coal fire in China

A coal fire is an earth fire that has developed in a coal seam or in relocated coal . It often arises spontaneously through spontaneous combustion . The prerequisite is that the carbon comes into contact with oxygen. In coal seam fires, this can happen naturally when the seam comes to the surface of the earth through mountain formation and erosion . Such fires are also caused by underground mining when air reaches the seams through ventilation (fresh air supply). The fires often start underground in an old man (abandoned cavity), in which there is still residual coal.

Coal fires can also occur after the coal has been relocated. Burning heaps are known here - fires in coal and coke heaps , fires in spoil heaps that still contain enough residual coal, especially in isolated places with increased concentration - and fires during the transport of coal in ships and in railroad cars.

As long as the reaction temperatures are in the range of approx. 150 to 500 ° C, one speaks of incomplete combustion or smoldering fire . This type of burn occurs when there is a lack of oxygen . Above 500 ° C, the fire turns into a smoldering fire (up to approx. 1000 ° C) or a flame fire (up to 1200 ° C) if there is sufficient oxygen , and complete combustion takes place .

Types of coal fires

Coal seam fires

Coal fire in Xinjiang (China)

Coal seam fires can be subdivided into near-surface fires in outcropping seams, i.e. seams emerging at the surface, where the oxygen comes from the air , and fires in mines at greater depths. There the oxygen comes from the ventilation .

Spontaneous coal fires

The cause of spontaneous coal fires is the flammability of the coal. In a coal fire , the oxygen reacts with the solid molecules in the fuel . These exothermic reactions take place at all temperatures. However, the speed is strongly dependent on temperature, so the reaction rate increases almost exponentially with increasing temperature . If a fuel is in a comminuted form, such as a bulk solid , or if the solid is porous, oxygen is present in the entire system.

Subcritical storage occurs when the thermal energy released inside the bed is less than the thermal energy that can be transported to the edge of the bed by thermal conduction and released to the environment via the bed surface. However, if more heat energy is released inside the solid bed than can be discharged to the outside, the system goes into a critical state. The temperature inside rises, leading to a further increase in the reaction rate and consequently to self-ignition .

Two essential factors decide whether spontaneous ignition occurs or not, the ambient temperature and the size of the bulk:

• The higher the ambient temperature, the faster the oxidation reactions take place and the greater the rate of heat release inside the bed.
• The larger the bed, the more difficult it is for the heat generated inside to be dissipated to the outside, that is, the faster a spontaneous combustion fire occurs. The poor heat dissipation is due to the fact that the porous or comminuted substances usually have a low thermal conductivity ; they have an insulating effect.

The most frequently mentioned parameter for starting this process is the auto-ignition temperature (SET). It is not a " material constant ", but always depends on the bulk size and geometry, in particular the ratio of volume to surface and decreases with increasing bulk volume. Of course, the auto-ignition temperature also depends on the properties of the respective fuel. These include the calorific value , the thermal conductivity and the grain size . Your specification is therefore a bit tricky, as you always have to specify the exact test conditions. Under the same conditions, the auto-ignition temperature for hard coal will be higher than that for lignite .

In contrast to a "tangible" source of ignition, such as an open flame or a hot surface, the process of self-ignition takes place without any external influence. If a bed is sufficiently large, this process can also take place at temperatures that are in the range of the annual mean temperature of a location. This was the case, for example, with the so-called Senate Reserve in Berlin. The coal stored there was partly supercritical and therefore self-ignited. It should be noted that the induction times, i.e. the times from the beginning of storage to ignition, become shorter, the larger the bulk and thus the lower the self-ignition temperature is. In the case of the Senate Reserve, the induction period was several years.

Lignite can start to burn spontaneously at temperatures of approx. 40 ° C to 60 ° C, while this is only possible from 140 ° C with the highest quality anthracite coal . The fire usually starts a few decimeters inside the coal, at a depth where, on the one hand, the permeability of the coal still allows air to enter and, on the other hand, the ventilation does not dissipate most of the heat generated. The low thermal conductivity of carbon does not allow heat to be dissipated without fluid circulation.

Factors that affect spontaneous inflammation include:

• Air circulation
• Climate ( arid or semi-arid )
• Coal quality and type (coal content, proportion of volatile components, degree of coalification)
• Particle size (with a smaller grain size , the surface and thus the risk of spontaneous and external flammability is greater)
• Geological and geomorphological conditions
• Influences of mining (open pits, cracks, subsidence )
• Hydrogeological influences (moisture content)

The spontaneous ignition of coal takes time. It depends on many factors, among others, the ambient temperature, but also on the volume of coal, in laboratory testing, ie on the sample size (see also the recognized mechanisms of Heuselbstentzündung ). The time to self-ignition is another measure of the charcoal's propensity to ignite. With large amounts of coal, for example in situ , the necessary minimum ambient temperature is indeed lower than with small amounts of coal, on the other hand it takes a very long time, usually months, for a coal sample to ignite.

Where a seam is close to the surface of the earth, the air has an immediate and more effective access. Such fires arise spontaneously here and can burn for decades. All in all, at least 20 to 30 million tons of coal are destroyed annually by these fires around the world. At least ten times the amount of coal is made unusable for mining because the remaining coal is no longer accessible or can no longer be mined economically.

There are two heat-producing adsorption processes:

• The physisorption of oxygen is possible up to about 50 ° C and provides an amount of energy of 42 kJ / mol.
• The chemisorption of oxygen creates a whole series of chemical compounds after overcoming the activation energy in the coal surface. Arise from the present there carbon, hydrogen and oxygen atoms to energy output of more than 100 kJ / mol as peroxides . These newly formed molecules also oxidize with the release of heat when the temperature rises further and escape mainly as carbon dioxide , carbon monoxide or water vapor .

The main reactions of carbon with atmospheric oxygen are:

• C and O ₂ form CO ₂ , releasing 394 kJ / mol
• 2 C and O ₂ form 2 CO, releasing 170 kJ / mol

Externally ignited coal seam fires

Coal seam fires are mainly caused by processes of spontaneous combustion. In a few cases, however, external ignition is possible. In the end, it is not possible to tell how the fire started. This applies in particular to fires underground, but also to near-surface fires insofar as they are related to near-surface mining. Possible causes are electrical equipment in an improper condition, overheated rollers of conveyor belts as well as carelessness during blasting, welding or grinding work.

As a rule, the fact that residual coal is left behind in dismantled seam parts or the accumulation of coal dust in large quantities also plays a role. Consistent compliance with mining regulations rules out such external ignition.

Underground coal seam fires can interact with methane explosions or coal dust explosions . Coal seam fires close to the surface often ignite forest fires and vice versa. This was reported from the USA, but especially from the Indonesian island of Sumatra .

Coal fires after promotion

Fires in coal stores

The mined coal, but also coke , is often stored for months in large heaps . There are legal regulations to avoid spontaneous combustion. For example, for coal and coke heaps in the mountain inspectorate area of North Rhine-Westphalia, it was stipulated that the coal must be stored in horizontal disks each no more than six meters high. A maximum dump height is determined depending on the type and type of coal.

Older heaps can often still contain considerable amounts of coal. Britain has had significant problems with burning heaps. However, these have now been dug up and greened. The heaps that are still burning in Germany today are partially monitored from the air with thermal imaging devices . These comparatively small fires are suppressed by injecting cement or anhydrite .

Coal with a grain size of less than 0.5 millimeters is processed in pulverized coal plants. A fire is rarely triggered by spontaneous combustion, but usually by an externally ignited dust explosion . The fire protection regulations of the employers' liability insurance association are very rigid here. Such systems are often operated using inert gas to reduce the oxygen present. Care must be taken to protect against flying sparks, high temperatures (max. 80 ° C) and the carbon monoxide value to indicate smoldering fires.

Coal fires during transport

In the time of steam shipping, fires broke out during the transport of coal. Initially, the coal for the still less common steamships was transported on wooden sailing ships . In the period from 1871 to 1880, 152 British ships were damaged, 68 were total losses and 84 were badly damaged. After initial scientific investigations, it was recognized that the number of fires increased with the length of the journey and the amount carried. The first iron ship was built as early as 1838, but this type of ship did not catch on. It was only when the first steel ships were built in Great Britain after 1881 that coal transport lost part of its danger because the coal could now be transported in non-combustible steel bunkers.

According to investigations into the explosion of the US battleship Maine in February 1898 in the port of Havana, a coal fire is assumed to be the trigger for the ignition of the black powder stores in the ammunition chamber adjacent to the coal bunker. Immediately after the disaster, the American public, led by publishers William Randolph Hearst and Joseph Pulitzer , accused the former Cuban colonial power of Spain of sinking by mine or torpedo , which tensions in Spanish since the outbreak of the Cuban War of Independence two months later -American war escalated.

In 2004, Robert Essenhigh formulated a theory that a smoldering fire in a coal bunker on the Titanic , which had been documented by the Southampton Harbor Fire Department , caused the captain to drive faster than the situation was appropriate despite the risk of icebergs . The fire on the starboard side , between boiler rooms 5 and 6, could have been fought in such a way that the coal from the affected bunker was shoveled into the boiler faster than usual in order to get to the burning coal. This was the usual procedure at the time for smoldering fires in the coal bunker.

At the present time, bulk carriers carrying coal can still catch fires by spontaneous combustion, as happened in Bremen in November 2003. There a smoldering fire broke out in a section in which 5000 tons of coal lay during a five and a half week drive, which was discovered in Bremen while unloading. There are safety regulations for such transports, such as the Canadian Notice To Shipmasters Loading Coal , in which safety instructions for the captain are laid down.

Coal seam fires worldwide

Coal burns in all coalfields in the world. The main countries that report coal fires are listed below.

India

In addition to the Ranigani and Singareni districts , fires are particularly raging in the Jharia region in northeast India, west of Calcutta . In 1997 there were around 160 individual fires on an area of ​​700 square kilometers. The first seam fires were discovered in 1916, the amount of unused coal burned since then is estimated at 60 million tons (as of 2011).

In connection with the fires, there are reports of landslides , quarries and subsidence . Since these areas are densely populated, the associated local environmental pollution is particularly high.

The coal industry also encourages coal fires, as it gives the atmospheric oxygen improved access to coal, on the other hand affect or prevent the fires the progress of mining. It is estimated that around 70 percent of the fires in India are mining-related.

United States

Burn crack with efflorescence

Many coalfields in the United States are affected by spontaneous coal fires. The Federal Office of Surface Mining (OSM) maintains a database (AMLIS) that lists 150 fire zones for 1999. Not only Kentucky , Pennsylvania and West Virginia in the east of the Appalachian coalfields are affected, but also Colorado and the Rocky Mountains .

There are 45 known fire zones in Pennsylvania. The most famous is the fire at the Centralia Mine , in the anthracite coal region of Columbia County . These fires have been burning since 1962 and spreading beneath the city. In Centralia , attempts were made to extinguish the fire, but in the end the city was largely abandoned because of the fires.

In Colorado , coal fires started as a result of fluctuations in groundwater levels . With such fluctuations, the coal temperature can increase by up to 30 ° C, which can initiate spontaneous combustion.

In North Dakota , coal fires can be found in the Theodore Roosevelt National Park region . The Lewis and Clark Expedition (1804 to 1806) reported fires. These have even occurred naturally there for about three million years and have shaped the landscape. For example, there is an area of ​​around 4,000 square kilometers with coal slag , called clinker or scoria in English , in the Theodore Roosevelt National Park. For example, the view from the scoria point of the fiery red coal slag is spectacular .

Germany

In the Zwickau coalfield between Planitz and Cainsdorf (city of Zwickau ), a coal seam burned from 1474 or 1479, and in 1640 another was created by igniting a shaft through an explosion in the Thirty Years' War , which could not be finally extinguished until 1880. In 1837 Ernst August Geitner set up a nursery on this Planitz earth fire , in which tropical plants were grown. In Dudweiler in the Saarland, a coal seam was ignited around 1668 and is still burning today. This so-called Burning Mountain developed into a tourist attraction that Goethe also visited. Also known is the so-called Stinksteinwand in the Schwalbenthal on the eastern slope of the Hoher Meissner in Hesse, where several seams ignited centuries ago after the lignite mining stopped and their combustion gases still come to the surface today.

Along with hard coal mining, there were and still are up to two coal fires per year and mine. Due to the concentration of hard coal production in the Ruhr area (seven mines, several burning heaps ), the Saarland (one mine) and the Ibbenbürener Steinkohlenrevier (one mine) (as of 2012), advanced coal fire prevention and coal fire fighting methods have been developed in these areas. Today the causes of underground coal seam fires are mostly to be found in so-called "creeping weather" and in defective operating resources. Creeping weather is air volume flows in a mine (“ weather ”) that unintentionally move into areas that have already been insulated or separated, for example into areas with fine-grained coal. Extensive prevention, control and rescue measures have meant that serious mine accidents with personal injury rarely occur in Germany. Self-extinguishing webbing materials, stationary and mobile CO, CO ₂ and other gas measuring devices are used for this purpose. The mine brigades and their regular exercises to prevent and extinguish coal fires are just as important .

After the closure of the last underground lignite mining on Hirschberg near Großalmerode in Hesse in 2003, lignite is only mined above ground in Germany , in the Rhenish district , in the Central German district and in the Lusatian lignite district . Here, too, occasional fire incidents can occur if the overburden above the lignite seam is removed very early and the lignite can subsequently come into contact with the oxygen in the air for a long time. However, this is avoided by a correspondingly managed overburden and coal extraction . Here, too, there are control precautions and plant fire brigades or mine brigades that recognize and combat any eventual situations at an early stage.

Austria

The 100-meter-high spoil dump of the hard coal mine in Fohnsdorf , which was operated from 1856 to 1980, has been burning inside for decades, whereby the SO ₂ / SO _{3 can} sometimes be smelled in the area. In 1943 there was the largest dump explosion there, smaller ones were commonplace until 1961, thanks to improved process engineering, more of the fine coal dust got into the product and less onto the dump.

The coal fire burns the clay fraction into slag. This has been ground since 1980 as red sand, for example for thermal insulation , concrete aggregate, garden design or tennis courts. Unburned black dump material, on the other hand, as clay tile aggregate with its own calorific value, replaces sawdust as a gas-entraining agent or fuel. With a current mining rate of 80,000 t / a (2011), the 5 million m³ dump could be used up in 30 years.

Rest of Europe and Russia

The number of coal fires in Europe has also decreased in line with the decline in mining. Some fires are reported from Central Europe , namely Poland and the Czech Republic, as well as from Eastern Europe , namely the Ukraine . The latter has stored two billion tons of coal in 2100 heaps. Of these, around 140 heaps are burning. In 1998, 74 coal fires were reported from Russia . Affected are the Kuzbass coal basin , the coal basins near the cities of Pechora and the Donets basin, which is partly on Ukrainian territory . In Kosovo , coal seams up to 20 meters thick are burning in the opencast mines and in the area of ​​the former underground mining in the Amselfeld .

Africa

The large coal fields of Africa are in the south, in South Africa , Zimbabwe , Botswana , Mozambique and Zambia , where fires are also most common in the coal deposits.

Australia

Five kilometers north of the town of Wingen in New South Wales - if you assume a constant speed - Burning Mountain , the world's oldest seam fire , has been burning for about 6000 years . Currently the fire is 30 meters below the surface and moving forward at a rate of one meter per year. To date it has covered a distance of six kilometers. Other coal fires are also known.

China

In China, the world's largest coal producer with an annual output of around 2½ billion tons, coal fires are a serious problem. It is estimated that around 10 to 20 million tons of coal fall victim to the flames each year in northern China, and 100 to 200 million tons become unusable for mining. The coal fires stretch across a belt throughout northern China, naming over a hundred large fire areas, each containing a large number of individual fire zones. This makes China the country with the most coal fires. The focus is on the provinces of Xinjiang , Inner Mongolia and Ningxia . In addition to the losses from the burned and unusable coal, these fires contribute to air pollution and significantly increased greenhouse gas emissions and are therefore a problem of international concern. The world's most intensive deletion activities are therefore carried out in China. New extinguishing methods are being developed in the coal fire research project as part of the Sino German Coal Fire Research Initiative .

other areas

The Indonesian Forest Fire Prevention and Control Project (FFPCP) reported coal fires that burned for four years. There were also two new fires in the Suban Jeriji region . Coal fires have also been reported from Venezuela , but no more detailed information has been provided.

Dealing with coal seam fires

Radiation temperature measurement

Avoidance

Coal fires close to the surface occur largely spontaneously and unintentionally, i.e. without someone having ignited them directly. Coal fires have also been proven from geological times, for example through clinker adjoining rock. Nevertheless, almost all known coal fires today are ultimately of human origin. Mining is essential here . Avoiding coal fires means mining without fires . There are many suggestions for this, ranging from modified mining technology , modified cutting or alternative mining management to other ventilation methods. The complete extraction of coal is particularly important, i.e. avoiding residual coal, in particular in the form of small pieces of coal or coal dust. The proper custody of near-surface small-scale mining is another issue.

Underground coal seam fires only occur when existing regulations are disregarded. This happens particularly frequently in the Chinese mines, which are under great pressure to perform, but coal fires are also not uncommon in other areas, including the Ruhr area . More often mines were abandoned because of such fires.

Exploration of fire zones, measurement technology

Measurement of the distribution of electrical conductivity in the subsurface with a sensor suspended from the helicopter

When extinguishing a coal seam fire close to the surface, it is advantageous to know its location and subterranean extent as precisely as possible. In addition to researching the geographical, geological and infrastructural environment, further knowledge can be gained through direct measurements. The focus is on:

• Temperature measurements on the earth's surface, in crevices and boreholes, for example with radiation thermometers
• Gas measurements to describe the ventilation system of the fire (quantities and speeds) and the gas composition to describe the fire reactions
• Geophysical measurements on the ground as well as from airplanes and helicopters to record the distribution of conductivities or other parameters in the subsurface. The conductivity measurements map changes in humidity in the vicinity of the fires. For example, magnetic measurements show changes in the magnetic properties of the host rock due to the effects of heat.
• Remote sensing methods from airplanes and especially from satellites . In addition to high-resolution optical mapping, thermal images and hyperspectral data also play a role. The coal fires, which are several hundred to over a thousand degrees Celsius, can show themselves with a temperature rise of only a few degrees on the earth's surface. This is in the order of magnitude of the temperature difference between the side of the slope, which is lit by the sun and the side of the slope in the shade, of an overburden dump or a sand dune.

Underground coal fires are monitored by sensors permanently installed in the mines. In addition to temperature, pressure and weather speed , this also records various gas contents. A developing fire is reported promptly in the mine control room. The system is primarily used for the early detection and rescue of endangered miners.

deletion

Combustion triangle

A fire needs fuel (coal), oxygen (air) and energy (heat) to continue. The interaction of these three moments is usually represented as a combustion triangle.

These three factors allow fire fighting methods (extinguishing methods) derived from them . The fire can be separated from other fuel, for example by aisles or refractory barriers. Some fires, especially on steep slopes, can also be completely excavated.

In the case of coal seam fires close to the surface, the oxygen in the air can be prevented from flowing in by covering or gas-tight barriers. Alternatively, the outflow of the fire gases can also be prevented so that the fire suffocates on its own exhaust gases.

Energy is extracted by cooling, usually by injecting large amounts of water. Remnants of dry coal can, however, generate absorption heat by absorbing water , so that a fire that has been extinguished can re-ignite itself after it has been drained. Therefore, more heat energy has to be extracted than the fire generates.

In practice, these methods are combined. When choosing a method, the availability of resources is also decisive. This applies in particular to water, for example in arid areas, and to covering material such as loess or clay .

At present, near-surface coal seam fires are routinely only extinguished in China. A standard method has been developed here, which essentially consists of the following phases:

1. Level the area above the fire zone with heavy equipment in order to make it drivable.
2. Drilling of the fire zone in a regular drilling pattern at about 20 meter drilling intervals down to the depth of the source of the fire.
3. Injection of water or mud into the boreholes over a long period of time, usually around one to two years.
4. Cover the entire area with an impermeable layer about one meter thick, made of loess, for example.
5. Greening, as far as climatically possible.

Work is being carried out on refining this method, for example through additives to the extinguishing water or the use of alternative extinguishing agents .

Underground coal seam fires are usually extinguished by inerting by the mine weir. For this purpose, the affected area is isolated by building dams in the routes . Then, inert gas , usually nitrogen , is introduced over a longer period, to which most existing pipelines to be used.

Monitoring of fire zones

Zones in which coal seams burn near the surface of the earth, but also potential fire zones (risk areas), must be monitored regularly. This enables the early detection of a new fire and its fighting in the initial stage. Extinguished fire zones must also be monitored, as they can start to burn again at any time. This happens mainly because heat islands that have remained in place during extinguishing can last for years because of the low thermal conductivity of the rocks. Large-scale surveillance is conceivable with satellite-based methods. The monitoring of individual fire zones can also be guaranteed by repeated visits with the use of appropriate measurement technology (temperatures, gas measurements, geophysical measurements), since the fire zones only move relatively slowly.

The risk of underground coal seam fires is limited by a permanently installed sensor system, as countermeasures can be taken in good time.

Environmental impact

The spontaneous coal seam fires have significant environmental impacts through the production of greenhouse gases, both globally as well as regionally and locally. In addition to the production of toxic gases, the landscape-changing consequences of mountain subsidence are particularly relevant.

Global environmental impact

In addition to the loss of fuel, coal seam fires produce greenhouse gases such as carbon dioxide , carbon monoxide , sulfur dioxide and methane in the order of magnitude of the emissions from German car traffic. The spontaneous and uncontrolled coal fires are therefore a relevant environmental problem in this respect as well. In a major inquiry (Drucksache 15/3740) in June 2005, the German Environment Ministry stated that it was investigating the question of whether the costs of extinguishing coal fires, which often lasted for years, were not partly due to the greenhouse gas emissions avoided with the help of the Clean Development Mechanism (CDM) of the Kyoto Protocol can be refinanced.

Regional and local environmental impacts

The adaptation strategies of animals and plants to coal fires depend on the duration of the event and the extent of the area affected. Furthermore, geomorphological changes are to be expected. So crevices appear on the surface of the earth; The reduction in volume of the coal seam can lead to collapses and landslides. The remains of the burned coal can form a landscape in large-scale coal fires such as in the Powder River Basin in the USA.

Centralia, Pennsylvania

The biologist Tobin-Janzen examined the effect of the near-surface fire of an anthracite coal mine that broke out in Centralia (Pennsylvania) in 1962 on the population of soil bacteria. About 1.2 square kilometers are currently affected. The area examined is characterized by the fact that hot gases escape from the moving fire zone. This leads to a rapid change in soil temperature as well as soil biology and chemistry.

As expected, the diversity of soil bacteria decreased sharply with increasing temperature (47 ° C to 75.7 ° C). The thermophilic bacterium Geobacillus thermoleovorans , which lives in the temperature range between 45 ° C and 85 ° C with an optimum growth rate of 70 ° C, was detected.

In addition, there was evidence of sulfur bacteria and bacteria, the nitrification of ammonia (NH ₃ ) or ammonium ions (NH ₄ ⁺ to) nitrate (NO ₃ ^- ) operate.

Overburden dumps Anna 1 and Anna 2

The salvage dump Anna 1 in Alsdorf of the former Anna mine has an area of ​​41 hectares, is up to 75 meters high and has been in use since around 1850. The special thing about it is that there have been wandering smoldering fires there since the middle of the last century. In the Anna 2 dump, similarly old but only 26 hectares in size, there are also covert fires. This means that there is a special microclimate on the heaps, which, also because of the danger associated with the fire, has made the heaps into an untouched and rare biotope .

Many species of insects and spiders of Mediterranean origin could be observed on Anna 1. These survive the cold winter in the region because the ground temperature has increased due to the fire. These include, for example, the wasp spider and the blue-winged wasteland insect .

Peat fires

In the wild, i.e. in moors , peat fires caused by spontaneous combustion occur extremely rarely. Although the surface temperature in a raised bog can rise to up to 77 ° C due to solar radiation and escaping fermentation gases such as methane could ignite, no bog fires have been proven to be spontaneous. The low storage density and the good ventilation of dry peat moss do not allow any heat build-up ( soil horizons ). Even in summer, the ground temperatures do not reach auto-ignition temperatures even at shallow depths. The temperature fluctuations during the day due to nocturnal radiation with clear skies are also considerable and can enable ground frosts from September to June.

In the tropics and subtropics, however, smoldering fires have been documented in deeper soil layers. Especially in periodic dry seasons or long-lasting droughts, abnormally increased soil temperatures occur in boggy soils or bog soils or sediments of West Africa . This overheating of up to 600 ° C can occur where sediments cover layers of peat and allow heat to build up. Self-ignition on the surface of soils with a high organic content has not been proven, although it cannot be ruled out that wildfires could be triggered by an exothermic reaction of soils with a high organic content.

literature

• R. Boekemeier, H. Wang, L. Zhu, S. Elleringmann: Hoellenfahrt through China. In: GEO , 9/2002, Hamburg, pp. 21-29.
• C. Buhrow, G. Lippmann, MT Stöttner: Coal fires in the People's Republic of China. In: Glückauf , 10/2004, pp. 468–494.
• E. Roloff: Fire out of control. Coal seams are burning in many places and can hardly be extinguished. In: Süddeutsche Zeitung , May 19, 2010, p. 16.
• T. Wündrich: Protection goal- oriented systematics for the sustainable management of near-surface coal seam fires. Dissertation, 2012.

Web links

Commons : Coal Seam Fires  - Collection of Images, Videos and Audio Files

• Coal fire research platform (English)
• Chinese-German research project ( Memento from March 20, 2014 in the Internet Archive ) (English)
• Coal fire research at HarbourDom
• Communication from the GeoUnion
• Inferno in the underworld
• Burning coal seams: fire under the earth sueddeutsche.de , January 17, 2008
• Hellfire - life on hot coals at arte.tv

Individual evidence

1. ↑ Guidelines for the approval of coal and coke heaps in the area of mining supervision , circular of December 9, 1971 , paragraphs 4.22–4.223
2. ↑ Understanding self-ignition of coal ( Memento from May 19, 2006 in the Internet Archive ) (PDF file; 642 kB)
3. ↑ New theory: coal fire is said to have triggered the "Titanic" disaster. In: Spiegel online , November 8, 2004, accessed November 25, 2013.
4. ↑ Transport Canada: Notice To Shipmasters Loading Coal ( Memento of February 5, 2013 in the Internet Archive )
5. ↑ Klaus Sieg: In the devil's black kitchen . In: VDI news . October 14, 2011, ISSN  0042-1758 , p. 3 .
6. ↑ John Beauge: Remaining handful of residents can stay in Centralia for the rest of their lives, settlement says. In: PennLive Central PA. PA Media Group, October 30, 2013, accessed November 17, 2013 . 
7. ↑ John P. Bluemle: North Dakota's Clinker.
8. ^ Emil Herzog: History of the Zwickau hard coal industry , p. 106f.
9. ↑  ( Page no longer available , search in web archives ) Description of the district Niederplanitz in Zwickau Süd
10. ↑ Plume of smoke after the dump explosion in 1943 Fohnsdorf (picture below left)
11. ↑ Utilization of the burning dump in Fohnsdorf - burnt clay and brick pore formers ( Memento from July 24, 2012 in the web archive archive.today )
12. ↑ www.dachbegruenung.at Roh-Halditt as an additional fuel (energy substitute) for the brick industry, accessed on February 16, 2014
13. ↑ Natural Coal Seam Fire at Burning Mountain. ( Memento from August 1, 2012 in the web archive archive.today )
14. ^ Most underground coal fires (country). Retrieved September 7, 2021 (German). 
15. ↑ Effects of global energy and resource requirements on global climate development (question 44), printed matter 15/3740, September 2004 (PDF file; 205 kB)
16. ↑ Microbial Ecology of the Centralia, Pennsylvania Mine Fire
17. ↑ nabu-aachen-land.de: Mine dumps in the Aachen area

This article was added to the list of excellent articles on September 1, 2005 in this version .