what year was underground mining limited?
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what year was underground mining limited?
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The world still have huge piles of coal reserves one of those countries is Botswana and South Africa in Africa.
What are Coal seam?
Like all fossil fuels, global coal reserves are very unevenly distributed.
The UK and Europe were fortunate in having extensive coalfields that powered the Industrial Revolution. The diagram shows the distribution of the major Carboniferous mires which became coal-bearing rocks across Europe, either outcropping at the surface or buried beneath younger rocks.
It is evident from this map is that not all countries shared the same good fortune - either such rocks were deposited, but were subsequently eroded away, or they were never deposited in the first place.
Carboniferous Britain and north Europe formed a low-lying plain backed by newly formed mountains to the south and a shallow sea to the north, beyond present-day Scandinavia. Tropical waterlogged mires developed across Britain and Ireland, through the southern North Sea into Belgium, the Netherlands and northern Germany and east into Poland, as well as between Greenland and Scandinavia. It is likely that coal formed across the whole of this area.
Erosion also helps to expose Carboniferous coals by removing overlying, younger rocks. As a result, surface mining is common in the Ruhr area of Germany, in Poland, in the Midland Valley of Scotland, and in parts of Lancashire and Yorkshire.
Production of large quantities of coal in the UK during the 19th and 20th centuries led to the progressive depletion of reserves.
In 2005 underground mining was limited to the Carboniferous coalfields of Yorkshire and the East Midlands, with only one underground mine operating in South Wales. However, surface mining sites still work coal in most of the coalfields.
What is considered to be a reserve (i.e. the amount that is thought to be recoverable in the future under existing economic conditions) changes with time. The coalfields of northern England and the Midland Valley of Scotland that extend eastwards under the North Sea are examples of this. Although coal has been worked there in the past, it is not currently recoverable at a profit.
In 2004, the UK\'s coal reserves were estimated to be 1.0 × 109 t of anthracite and bituminous coal, and 0.5 × 109 t of sub-bituminous coal and lignite. Together, these two figures represent 0.2% of total global coal reserves.
The EU\'s coal reserves in 2004, after enlargement to 25 member states, stood at 100 × 109 t. The diagram shows the eight European Union Member States with the most significant reserves ranked in order of greatest tonnage. With a little over 100 × 109 t of coal of all ranks, the EU possesses approximately 10.2% of total global coal reserves.
Germany has by far the largest reserves (dominated by ‘hard’ brown coal and lignite), rivalled only by Poland for coals of higher rank. By contrast, the UK\'s reserves make a minor contribution to the European total.
The diagram also illustrates the production of coal in Europe since 1981. With the exception of Greece, production has declined, especially among the major producers. This trend reflects the ending of generous EU-supported government subsidies, which had allowed otherwise lossmaking mines to remain in operation.
In 2004, the EU produced approximately 593 × 106 t of coal. By contrast, it consumed 749 × 106 t yr-1 , making it a net importer of coal. Some countries (e.g. France and Spain) rely more heavily on imports than others.
The diagram shows the global distribution of coal deposits. The major areas are principally in the Northern Hemisphere, with the exception of Australia, the southern continents are relatively deficient in coal deposits.
A broad chain of large coalfields of Carboniferous age extends from the eastern USA, through Europe, the Russian Federation and south into China. A second chain of Permian coalfields is found in the southern continents - South America, India, southern Africa, Australia and Antarctica. The vast coalfields of the western USA and Canada are of Cretaceous-Tertiary age. Mesozoic-Cenozoic lignites are also important global sources of coal.
The diagram shows the breakdown of global reserves by continental regions. North America has 26% of total global coal reserves, South Asia and the Pacific (mainly Australia) have 30%, Europe 20%, and the Russian Federation 16%. The relatively sparse distribution of coalfields elsewhere is borne out by far less significant reserves in Africa and the Middle East (6%), and in South and Central America (2%).
In 2003, global proven coal reserves were estimated at 984.5 × 109 t, of which slightly over half (52.7%) was anthracite and bituminous coal and the rest (47.3%) was sub-bituminous coal and lignite.
Comparisons between the sustainability of coal production in different countries are made easier by calculating the ratio of proved reserves in the ground (R) to the annual production (P).
This R/P ratio has dimensions of tonnes divided by tonnes per year, which is equal to years (t/(t yr-1 ) = 1/yr-1 = yr).
The R/P ratio is therefore a measure of how long the coal reserve (or that of any other fossil fuel or non-renewable resource) will last, if the current annual production figure is maintained into the future.
In years to come, as reserves begin to run low, global coal prices may increase. More coal resources would then become economic to mine, to be reclassified as reserves. This would in turn raise the R/P ratio. It is therefore important to include the future conversion of resources to reserves when considering how long coal will last as a source of energy.
However, the current lack of coal resource data for many countries, together with uncertainties associated with predicting future changes in global coal prices make such calculations rather speculative. Of course, such speculations presuppose that coal continues to be favoured despite its contribution to global warming.