Coal is a fossil fuel formed in ecosystems where plant remains were preserved by water and mud from oxidization and biodegradation, thus sequestering atmospheric carbon. Coal is a readily combustible black or brownish-black rock. It is a sedimentary rock, but the harder forms, such as anthracite coal, can be regarded as metamorphic rocks because of later exposure to elevated temperature and pressure. It is composed primarily of carbon along with assorted other elements, including sulfur. It is the largest single source of fuel for the generation of electricity world-wide, as well as the largest world-wide source of carbon dioxide emissions, which, according to the IPCC are responsible for causing climate change and global warming. In terms of carbon dioxide emissions, coal is slightly ahead of petroleum and about double that of natural gas. Coal is extracted from the ground by coal mining, either underground mining or open pit mining (surface mining).
Coal has been used worldwide as a fuel for centuries.
Around 1842 coal became the main energy source for the Industrial Revolution, the expanding railway system of countries being a prime user to power steam trains. Britain developed the main techniques of underground coal mining from the late 18th century onward with further progress being driven by 19th century and early 20th century progress.
Because coal is found mainly underground, it must be mined or extracted prior to use. Large-scale coal mining developed during the Industrial Revolution, and coal provided the main source of primary energy for industry and transportation in the West from the 18th century to the 1950s. Coal remains an important energy source, due to its low cost and abundance when compared to other fuels, particularly for electricity generation. However, coal is also mined today on a large scale by open pit methods wherever the coal strata strike the surface and is relatively shallow.
However oil and its associated fuels began to be used as alternative from this time onward. By the late 20th century coal was for the most part replaced in domestic as well as industrial and transportation usage by oil, natural gas or electricity produced from oil, gas, nuclear or renewable energy sources.
Since 1890, coal mining has also been a political and social issue. Coal miners' labour and trade unions became powerful in many countries in the 20th century, and often the miners were leaders of the Left or Socialist movements (as in Britain, Germany, Poland, Japan, Canada and the U.S.)[3] Since 1970, environmental issues have been increasingly important, including the health of miners, destruction of the landscape from strip mines and mountaintop removal, air pollution, and coal combustion's contribution to global warming.
Prehistory.
An 120,000-year-old Stone Age coalstone hunting camp was discovered in 2005 by archaeologists in an opencast coalstone mine in Germany, its first known use being campfire cooking fuel for German hunters. China Coal Information Institute reports the Chinese mined coalstone for fuel since 10,000 years ago at the time of the New Stone Age, or Neolithic Era. "People in Shanxi, now the largest coal production base, have been burning coal as fuel since then." Coal usage was widespread in various parts of the world by the Bronze Age, 2000-1000 BC. Chinese usage of coal for smelting began in the Warring States Period (475-221 BC). They are credited with organizing production and consumption to the extent that by the year 1000 AD this activity could be called an industry. In the 11th century, the demands for charcoal of the Song Dynasty (960-1279) Chinese iron industry led to widespread deforestation. With the advent of coal replacing charcoal in the iron smelting process, thousands of acres of prime timberland were spared in China. China remained the world's largest producer and consumer of coal until the 18th century. Roman historians describe coal as a heating source in Britannia.
The earliest use of coal in the Americas was by the Aztecs. They used coal not only for heat but as ornaments as well. Coal deposits were discovered by colonists in Eastern North America in the 18th century.
Early coal extraction was small-scale, the coal lying either on the surface, or very close to it. Typical methods for extraction included drift mining and bell pits. In Britain, some of the earliest drift mines (in the Forest of Dean) date from the medieval period. However, the Romans exploited coal on a large scale as shown by the stores of coal at many forts along Hadrian's Wall, and the remains of smelting industry at forts such as Longovicium nearby.
As well as drift mines, small scale shaft mining was used. This took the form of a bell pit, the extraction working outward from a central shaft, or a technique called room and pillar in which 'rooms' of coal were extracted with pillars left to support the roofs. Both of these techniques however left considerable amount of usable coal behind.
The Industrial Revolution.
The Industrial Revolution, which began in Britain in the 1700s, and later spread to Europe, North America, and Japan, was based on the availability of coal to power steam engines. International trade expanded exponentially when coal-fed steam engines were built for the railways and steamships in the 1810-1840 Victorian era. Coal was cheaper and much more efficient than wood burning in most steam engines. As central and Northern England contains an abundance of coal, many mines were situated in these areas as well as the South Wales coalfield and Scotland. The small-scale techniques were unsuited to the increasing demand, with extraction moving away from surface extraction to deep shaft mining as the Industrial Revolution progressed.
Disasters.
Mining has always been dangerous, because of explosions, roof cave-ins, and the difficulty of mines rescue. The worst single disaster in British coal mining history was at Senghenydd in the South Wales coalfield. On the morning of 14 October 1913 an explosion and subsequent fire killed 436 men and boys. Only 72 bodies were recovered. It followed a series of many extensive Mining accidents in The Victorian period, such as The Oaks explosion of 1866 and the Hartley Colliery Disaster of 1862. Most of the explosions were caused by firedamp ignitions followed by coal dust explosions. Deaths were mainly caused by carbon monoxide poisoning, although at Hartley colliery, where the victims were entombed when the single shaft was blocked by a broken cast iron beam from the haulage engine, death occurred by asphyxiation.
The Monongah Mine disaster of Monongah, West Virginia 6 December 1907 was the worst of many mining disasters in American history. The explosion was caused by the ignition of methane gas (also called "firedamp"), which in turn ignited the coal dust. The lives of 362 men were lost in the underground explosion..
Modern mining.
Technological advancements have made coal mining today more productive than it has ever been. To keep up with technology and to extract coal as efficiently as possible modern mining personnel must be highly skilled and well trained in the use of complex, state-of-the-art instruments and equipment. Future coal miners have to be highly educated and many jobs require four-year college degrees. Computer knowledge has also become greatly valued within the industry as most of the machines and safety monitors are computerized
In the United States, the increase in technology has significantly decreased the mining workforce from 335,000 coal miners working at 7,200 mines fifty years ago to 104,824 miners working in fewer than 2,000 mines today. As some might see this as a sign that coal is a declining industry its advances has reported an 83% increase of production from 1970 to 2004
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