Even though most of the world deem electricity and clean cooking facilities as elementary accessories which everyone possesses, in many parts of the developing world most of the population is still lacking those two basic accessories. These countries are heavily dependent on coal, and there is a tremendous importance of improving the technology by which they extract and use coal. Coal is the largest source of electricity generation worldwide. It is also used in the steel and cement industry. The coal industry in developing countries will have a vital role in the next decades; with economic and social repercussions resulting from the approach governments take towards it.
Coal started to form about 300 million years ago. It is the transformed remains of vegetation which prehistorically occurred in swamps and bogs. Tectonic movements buried these bogs and swamps, usually to great depths. When they were buried, they were exposed to great temperatures and pressures. This was the catalyst for the transformation from the plant-like structure to coal. The first coal age, is known as the Carboniferous Period. (The Coal Resource 2)
Worldwide, there are over 984 billion tons of known reserves of coal. This would be enough to last us about 190 years, even if no new reserves are discovered. The biggest reserves are located in the USA, Russia, China and India. (The Coal Resource 3). Usually, the reserves are discovered undertaking exploration techniques. Frequently, the explorers create a geological map of the area which is suspected to hold reserves of coal, followed by geophysical and/or geochemical surveys. In the end, exploration drilling is performed in order to draw a precise picture of the area which is subject to development. However, the area will be transformed into a mine, only if it has a satisfactory quantity of coal, and the quality is sufficient so it is profitable to be recovered. Mining operations begin only when these premises are confirmed. (The Coal Resource 4)There are two methods of mining; Underground and Surface.
Underground: Underground mining is divided into two techniques; room-and-pillar and longwall mining. In the room-and-pillar technique, a series of interconnected chambers are built inside the coal seam. Pillars of coal are left standing in order to support the mine. These pillars can later be recovered, mining the coal while the workers are retreating. Finally, the roof falls and the mine can be abandoned. On the other hand, Longwall mining requires more careful and precise planning. First, there needs to be insurance that favorable geology exists throughout the area, before the work begins. Then the wall of coal is built, which is usually around 3 km long and 300m wide. When the coal is extracted, the roof is allowed to fall. Longwall mining allows for over 75% of the coal to be extracted, but it is much more costly, and requires more time for planning. The costs differ substantially. Room-and-pillar mining can cost under...