Coal-seam fire
Coal-seam fires have been slowly shaping the lithosphere and changing atmosphere, but this pace has become faster and more extensive in modern times, triggered by mining.
Two basic factors determine whether spontaneous combustion occurs or not, the ambient temperature and the grain size: Wildfires (lightning-caused or others) can ignite the coal close to the surface or the entrance of a mine, and the smouldering fire can spread through the seam, creating subsidence that may open further seams to oxygen and spawn future wildfires when the fire breaks to the surface.
[9] Globally, thousands of inextinguishable mine fires are burning, especially in China where poverty, lack of government regulations and runaway development combine to create an environmental disaster.
The oldest coal fire in China is in Baijigou (白芨沟, in Dawukou District of Shizuishan, Ningxia) and is said to have been burning since the Qing Dynasty (before 1912).
These relay pressure, temperature, airflow and gas composition measurements to the safety monitoring personnel, giving them early warning of any problems.
Besides destruction of the affected areas, coal fires often emit toxic gases, including carbon monoxide and sulphur dioxide.
In the case of near-surface coal-seam fires, the influx of oxygen in the air can be interrupted by covering the area or installing gas-tight barriers.
In 2004, the Chinese government claimed success in extinguishing a mine fire at a colliery near Urumqi in China's Xinjiang province that had been burning since 1874.
However, a March 2008 Time magazine article quotes researcher Steven Q. Andrews as saying, "I decided to go to see how it was extinguished, and flames were visible and the entire thing was still burning. ...
"[15] A jet engine unit, known as Gorniczy Agregat Gasniczy (GAG), was developed in Poland and successfully used for fighting coal fires and displacing firedamp in mines.
Time magazine reported in July 2010 that less expensive alternatives for extinguishing coal-seam fires were beginning to reach the market, including heat-resistant grouts and a fire-smothering nitrogen foam, with other innovative solutions on the way.
Beside losses from burned and inaccessible coal, these fires contribute to air pollution and considerably increased levels of greenhouse gas emissions and have thereby become a problem which has gained international attention.
[29] Also well-known is the so-called Stinksteinwand (stinking stone wall) in Schwalbenthal on the eastern slope of the Hoher Meißner, where several seams caught fire centuries ago after lignite coal mining ceased; combustion gas continues to reach the surface.
Mine fires started in this region in 1916 and are rapidly destroying the only source of prime coking coal in the country as well as the surrounding areas due to land subsidence and pollution.
In 1998, a total of 125 coal fires were located and mapped within a 2-kilometre strip either side of a 100-kilometre stretch of road north of Balikpapan to Samarinda in East Kalimantan, using hand-held Global Positioning System (GPS) equipment.
Extrapolating this data to areas on Borneo and Sumatra underlain by known coal deposits, it was estimated that more than 250,000 coal-seam fires may have been burning in Indonesia in 1998.
In 1982 and 1983 one of the largest forest fires in this century raged for several months through an estimated 5 million hectares of Borneo's tropical rainforests.
[32] A fire season usually occurs every 3 to 5 years, when the climate in parts of Indonesia becomes exceptionally dry from June to November due to the El Niño–Southern Oscillation off the west coast of South America.
In 1944, Longyearbyen Mine #2 on Svalbard was set alight by sailors from the German battleship Tirpitz on its final sortie outside of Norwegian coastal waters.
[citation needed] The Powder River Basin in Wyoming and Montana contains some 800 billion tons of brown coal, and the Lewis and Clark Expedition (1804 to 1806) reported fires there.
[39] The novel Germinal by the French novelist Emile Zola describes a fictional coal fire called Le Tartaret.
The 1991 film Nothing but Trouble, directed and co-written by Dan Aykroyd, features a town, Valkenvania, that has an underground coal fire that has been burning for decades.
