How coal is extracted from coal seams depends on how deep the seams are, and also the geology and geography of the area it's being mined in.
If the coal seams are near the surface, the coal is extracted by either:
open pit mining, in some countries, synonymous with a quarry
strip mining, coal is extracted by large machines in strips; the strata on top of the coal are allowed to fall back to where the seam was, once the mining has finished.
Most open cast mines in the USA extract lignite. In South Wales opencasting for steam coal and anthracite is practised.
However most coal seams are too deep underground for open cast mining. Most coal is extracted by either:
deep mining, The shaft is dug vertically deep into the ground. These tend to be the most productive pits and often contain high quality coals. Coal is lifted to the surface with hoists.
slope mining, The shaft is dug at an angle of about 45 degrees to the coal seam. Coal is moved to the surface with a conveyor belt.
drift mining, The shaft is dug into the side of a mountain. Drift mines are smaller than deep mines and are common in South Wales - also in West Virginia. Coal is transported from the mine to the treatment plant via conveyor belts or mine railway cars.
Mining can be very dangerous and although in the West disasters are now rare, pit collapses, explosions and flooding are still common in parts of the world. China tries to keep its mining disasters hidden, but news leaks out.
Now coal mining is highly unionized, and the unions are sometimes militant. Mining communities are often close-knit and very religious with a strong sense of community spirit. They also tend to be strongholds of left-wingBritain and possibly the world is Tower Colliery at the northern end of the south Wales valleys. This colliery was started in 1805 and at the end of the 20th century it was bought out by its miners rather than allow it to be closed.
Coal mining frequently causes significant adverse environmental impacts. Strip mining typically destroys most environmental value in the land through which it passes. However open-cast mining can be almost as severe in its impact. All forms of mining are likely to generate areas where coal is stacked and where the coal has significant sulphur content, such coal heaps generate highly acidic metal rich drainage when exposed to normal rainfall. These liquors can cause severe environmetal damage to receiving water-courses.
Stefan Berger and Andy Croll are organising a conference on Comparative Coalfield Histories at the University of Glamorgan in the spring of 2002.
The University of Glamorgan, situated at the heart of the South Walescoalfield, will be an ideal place to examine questions regarding the distinctiveness of coalfield societies, the similarities that unite coalfields otherwise separated by time and space, and the differences that mark them out from one another.
The nature of the work processes, the character of the social structure of the communities, the topography of coalfields and the often turbulent histories that unfolded within them, are all factors that have contributed to strong public images of the world of mining.
Coalfield's performing a substantial part of its contractual undertaking was further evidence that the parties had a contract, as it is hardly plausible that Coalfield would have done so much work, or Maddox permitted it to do so much work, had the parties not thought there was a contract.
Coalfield's repeated requests to Maddox to sign a proposal that, so far as the record shows, contained no unusual, coercive, or one-sided terms--a proposal that could not be said to invite rejection or a counterproposal--were in effect reasonable requests for assurances, or close enough to be treated the same by the law.
Coalfield's proposal was vague: "Schedule to provide for installation within three (3) weeks if allowed to work 7 days per week around the clock." And if this was a commitment to completion within three weeks, it was only a conditional commitment, and one of the conditions--being allowed to work seven days a week--was not fulfilled.
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