Bituminous coal
Its coloration can be black or sometimes dark brown; often there are well-defined bands of bright and dull material within the seams.
Extraction of bituminous coal demands the highest safety procedures involving attentive gas monitoring, good ventilation and vigilant site management.
The fixed carbon content refers to the percentage of the coal that is neither moisture, nor ash, nor volatile matter.
When evaluated on a dry, mineral-matter-free basis, the fixed carbon content is the fraction of the coal that is not volatile organic matter.
[13] It gets its name from this tendency to form a softened, sticky mass when heated,[8] which reflects the presence of bitumen (mineral tar) in the coal.
Both are sapropelic, in contrast with most bituminous coal, which is humic (composed of decayed woody tissue of plants).
[14][15] In the United States, bituminous coal is further divided into subranks based on its heating value and fixed carbon content.
In order of increasing rank, these are:[17] Bituminous coal is used primarily for electrical power generation and in the manufacture of steel.
This usually takes place in peat bogs, where falling plant debris is submerged in standing water.
[24] Peat is mostly a mixture of cellulose, hemicellulose, and lignin that originally made up the woody tissue of the plants.
Bituminous coal has a composition of about 84.4% carbon, 5.4% hydrogen, 6.7% oxygen, 1.7% nitrogen, and 1.8% sulfur, on a weight basis.
[28] During coalification at bituminous rank, coal approaches its maximum heating value and begins to lose most of its volatile content.
[6] During coalification, the pressure of burial reduces the volume of the original peat by a factor of 30 as it is converted to coal.
[35] However, 90% of all coal beds were deposited in the Carboniferous and Permian periods, which represent just 2% of the Earth's geologic history.
[40] Vast deposits of bituminous coal of Pennsylvanian age is found in the Appalachian and Interior Provinces of North America.
Historically, the many seams scattered over rugged terrain in the Appalachians have been conducive to mining by small companies, while the great extent and gentle dip of beds further west favors very large-scale operations.
Bituminous coal fields are found in Poland[43] and the Czech Republic,[44] and the Polish deposits are one of the most important of that nation's natural resources.
[47] Other significant bituminous coal deposits are found through much of Europe, including France, Germany, and northern Italy.
[49] Extensive bituminous coal deposits of Permian age are found in Siberia, east Asia, and Australia.
[2] Maturation of bituminous coal at medium and low volatile subrank is accompanied by peak methane generation.
[8] Imidazolium-based ionic liquid solvents can reduce spontaneous combustion, which accounts for 2 to 3 percent of global annual carbon dioxide emissions.
[62] Bituminous coal quality is improved with floatation methods, which increase the fraction of vitrinite to yield a cleaner-burning product.
