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A large compost pile can spontaneously combust if improperly managed. Spontaneous combustion or spontaneous ignition is a type of combustion which occurs by self-heating (increase in temperature due to exothermic internal reactions), followed by thermal runaway (self heating which rapidly accelerates to high temperatures) and finally, autoignition. [1]
Coal dust suspended in air is explosive—coal dust has far more surface area per unit weight than lumps of coal, and is more susceptible to spontaneous combustion. However, five elements are needed for an explosion to occur: oxygen, an ignition source, coal dust, dispersion of the coal dust, and confinement of the dust. [4]
This "spoil tip" at the Ronchamp coal mines is colored red due to combustion. In some spoil tips, the waste resulting from industries such as coal or oil shale production can contain a relatively high proportion of hydrocarbons or coal dust. Spontaneous subterranean combustion may result, which can be followed by surface fires. In some coal ...
Spontaneous combustion is caused when coal oxidizes and airflow is insufficient to dissipate heat; this more commonly occurs in stockpiles and waste piles, rarely in bedded coal underground. Where coal fires occur, there is attendant air pollution from emission of smoke and noxious fumes into the atmosphere.
Coal refuse, also known as coal waste, rock, slag, coal tailings, waste material, rock bank, culm, boney, or gob, is the material left over from coal mining, usually as tailings piles or spoil tips. For every tonne of hard coal generated by mining, 400 kg (880 lb) of waste material remains, which includes some lost coal that is partially ...
The rank of coal is correlated with its geologic history, as described in Hilt's law. In the ASTM system, any coal with more than 69% fixed carbon is classified by its content of carbon and volatiles. Coal with less than 69% fixed carbon is classified by its heating value. Volatiles and carbon are on a dry mineral free base; heating value is ...
Spanish investigations found that it was likely started by spontaneous combustion of the adjacent coal bunker or accidental ignition of volatile gases. The 1898 US Navy investigation blamed an assumed mine, which caused public outrage in the United States and sympathy for the Spanish–American War .
The waste material from the Grootegeluk mine, particularly from the lower levels, is prone to spontaneous combustion. Various experiments have been conducted to discover the best way to cover this material as the mine is back-filled so as to minimize the risk. A concern is that the covering will become less effective as it absorbs oxygen. [13]