The environmental associated points in coal mines (each in opencast and underground) have been mentioned. April As coal is essential fossil fuel and its importance has been more prominent after super enhance in worldwide value of crude oil; coal mining is now important a part of civilization.
A. In number of ways coal mining tasks pollute surroundings. Environment problems related to coal mines are discussed below:
(1) Air pollution: Air pollution in coal mines is primarily because of the fugitive emission of particulate matter and gases including methane (CH4), sulphur dioxide (SO2) and oxides of nitrogen (NOx). The mining operations like drilling, blasting, movement of the heavy earth moving equipment on haul roads, assortment, transportation and handling of coal, screening, sizing and segregation items are the major sources of such emissions. Below-ground mine fire is also a serious source of air pollution in a few of the coal fields.
Excessive ranges of suspended particulate matter increase respiratory diseases comparable to chronic bronchitis and asthma instances while gaseous emissions contribute in direction of global warming in addition to causing health hazards to the exposed inhabitants.
Methane emission from coal mining is determined by the mining strategies, depth of coal mining, coal quality and entrapped gasoline content material in coal seams.
(2) Water pollution: The key source of water pollution within the coal mines is the carry over of the suspended solids in the drainage system of the mine sump water and storm water drainage. In a number of the coal mines, acidic water can be discovered within the underground aquifers. In addition, waste water from coal preparation plant and mine water are other sources of water pollution.
(Three) Land degradation: The opencast coal mines are developed at the floor, because of that these mines are additionally called floor coal mines. The overburden, i.e., the rock or soil overlaid the coal seam, are eliminated before extraction of coal. This overburden is dumped on floor, ideally on mined-out or decoaled area. Therefore, any such mining requires fairly large space on surface. Many a times, large forest areas are transferred for coal mining purpose. The land degradation is the results of creation and enlargement of opencast coal mines. The aspect of land degradation in underground coal mines is because of subsidence over the underground cavity resulted from underground caving.
(4) Noise pollution: Principal sources of noise pollution are blasting, motion of heavy earth shifting machines, drilling and coal handling plants etc.
(5) Solid waste: Main supply of solid waste in a coal mine is the overburden. Segregation of the stones within the coal dealing with plants and the coal breeze additionally contribute to the solid waste generation. Over-burden to coal ratio within the open cast mining is about 2 m3/tonne of coal or sometime extra. Due to this fact, the quantum of overburden generated and its proper administration is the principle concern space in coping with the environmental issue of opencast coal mines.
(6) Deforestation: As defined, the requirement of land for an enormous opencast coal projects are fairly massive. Many of the forest area, many a instances, are converted to mining area. Subsequently, giant forest areas are deforested to make a manner for big opencast coal mines.
B. The unscientific mining practices undertaken lead to large degradation of land within the type of subsidence, underground goaf full of water, mine fires, destruction of vegetation, era of wind blow mud and so forth. To mitigate above environmental issues a number of control measures, usually, are adopted. A few of the control measures are mentioned below:
(1) Subsidence: Subsidence of surface takes place on account of extraction of coal by underground mining. Subsidence is exhibited by cracks on floor and decreasing of land within the labored out areas compared to surroundings. The floor is rehabilitated by dozing and sealing of cracks adopted by plantation of trees. The subsided areas with medium-sized depressions are ideal for creating water pools and sustain green vegetation and likewise to satisfy the water needs of local folks.
(2) Abandoned mines: The mined-out areas are to be backfilled after which rehabilitated for growth of vegetation. Within the quarried areas water reservoir is developed for water harvesting. The massive voids created by open-pit mining cause land degradation. These voids will be gainfully utilized to serve as water reservoirs. This water supplies moisture for vegetation within the surroundings areas. The water is used for domestic provide after essential therapy. Irrigation to close by agricultural land also may be thought off.
(3) External overburden dump: The exterior dump area presents an unaesthetic appearance unless rehabilitated. Vegetative rehabilitation of these dumps prevents erosion and likewise improves aesthetics.
(4) Mine fireplace: The measures for controlling the mine fires, embrace dozing, levelling and blanketing with soil to stop the entry of oxygen and to stabilize the land for vegetal progress.
(5) Water and air pollution management: Mine water is pumped to a lagoon, which acts as a sedimentation pond. The overflow water, which is pretty clean, is drained out to natural drain or used for dust suppression activities. Equally, washery effluent is re-circulated by thickener and slime ponds. For lowering air pollution, water spraying and sprinkling is done on the haul /transport roads to suppress the mud generation.
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