Thanks so much.
Thanks so much.
Coal is a villainous dragon in modern industrial society. Its exploitation is not a matter of economic convenience and efficient satisfaction of energy demands: rather, it is a matter of governing elites and industrial tycoons banding together with the veiled intention of damaging the environment and perpetuating its continual deterioration. Why would they be so environmentally sadistic? why would they go out of there way to kill our planet? Because they know they are the creators of history who have opened up a new page in humanity's relationship with planet Earth, one that will mark them henceforth as the indisputable lords over man and nature, gods over the earth and tyrants over the multiplicity of non-human forces that man has struggled to manipulate over many millennia. And what are we doing about this? Allowing coal exploitation and generation to forge ahead as if it were merely a marginal issue? As if it were a trifling ailment in an otherwise perfectly healthy planet? No! The Earth--our precious home--is desperately ill and we have the technology to enable us to administer the right medicine and stop the terrible sickness that courses through its biotic and abiotic systems. There are only two sides in this momentous war: those who will stand up stalwartly to protect Mother Nature and oppose its murderous rapists, and those who will push forward determinedly with their malicious agenda of utter destruction of the beauty, harmony and integrity of the collective ecological heritage which is ours to share and preserve. It's time for everyone to choose their sides. Victory and defeat have nothing to do with right and wrong. You must simply fight against this terrible broadening shadow of loss and indiscriminate careless wastage, no matter the consequences. And even if Mother Nature is controlled beyond all redemption by the nefarious hostile forces of industry and exploitation, we must play our part to curb it in what way we can, to be remembered in history as the valiant few who boldly confronted the immensely powerful regime of filthy, ugliness and annihilation and furnished that glorious light of resistance and devotion in the midst of a treacherous selfish shadow.
Please I can not passovers this cours (Module 17, 5/7) after clicking on "finish button". thank to give me help. Aka Barthelemy
What are the steps taken to minimize the nuisance of surface mines?
definitivamente debemos buscar otro método para la generación de energía ya que el carbón solo causa problemas ambientales
Environmental impact comes in different stages physical, Chemical and remedial.
What is the environmental impact of mining and burning coal?
Coal produced by both surface and underground mining is used either to fuel electricity generation or for industrial and domestic heating, both of which result in atmospheric pollution, but here we are concerned with direct environmental impact on the land.
Surface and underground mining operations cause significantly different environmental problems. Those that surround surface mining are common to any large quarrying operation: sterilization of the land and restoration of quarry sites; dust; and noise while operating. Mining waste is not a problem since it helps to fill the hole created.
Underground mines produce less noise and dust at the surface, but cause land subsidence and generate long-lasting waste tips, even though some waste is used as backfill. As you will see, both operations can potentially cause water pollution.
Environmental impact of surface mining
Many environmental issues arise when surface mining is considered, and such mines regularly arouse local opposition. By their very nature, surface mines have a major impact on the landscape, involving the digging of enormous pits with accompanying noise, dust and traffic movements, and destruction of mature landscape.
Increasingly, in recent years the environmentally conscious public has used the planning processes to oppose and sometimes prevent mining on sites where the environmental impact would be severe.
Many steps can be taken to minimize the nuisance of surface mines. Topsoil is commonly stored in graded embankments around the boundaries of mines as a baffle against visual intrusion, noise and dust. On-site vehicles can be fitted with effective silencers. To prevent dust being raised on site, water bowsers spray haulage roads.
Lorries leaving the site pass through wheel washers and their loads are often covered. Furthermore, individual mines have lives limited to 5-10 years and operators are required to restore former sites to productive farmland, forestry or recreational use by re-spreading the original topsoil.
Environmental impact of underground mining
Underground mining operations have four significant environmental impacts:
• spoil heaps,
• methane build-up,
• subsidence and
• water pollution.
Spoil heaps have always been the principal surface feature of underground mining operations. However, legislation and technical advances have brought improvements in modern mines, and the closure of many of the UK's older mines has often been followed by successful rehabilitation of mine sites and spoil heaps by landscaping and tree planting.
Coal seams naturally generate methane, and as this is an explosive gas, build-up in old mine workings has to be prevented by venting to the atmosphere.
Such methane has been successfully used to generate saleable electricity or diverted into household gas supplies, which lessen its effect as a powerful greenhouse gas.
Subsidence is an inevitable hazard wherever underground mining is carried out. The major factors affecting the extent of subsidence are seam thickness and its depth beneath the surface.
The amount of subsidence can be calculated roughly by using the formula:
where s is the amount of surface subsidence (in m), t is the thickness of the worked seam (in m), and d is the depth to worked seam (in m).
Roof collapse will often start within 24 hours of coal extraction, but the full effects are transmitted rather slowly upwards, eventually resulting in subsidence at the surface. It may be over 10 years before the surface is completely stable again.
Vulnerable structures, such as conurbations, dams, viaducts, and historical buildings are protected by leaving coal unworked beneath them, but such protection may be extremely costly where it significantly affects the layout of the mine.
Most underground and some surface mines lie well below the water table. Both therefore have the potential to pollute any groundwater that flows through them.
The root cause of the problem is the action of aerobic bacteria on pyrite (FeS2) within the coal sequence. This process releases metal and sulphate ions into solution, which in turn causes the acidity of the mine water to increase:
Before mining, groundwater flow through coal sequences is usually sluggish and in general chemically slightly reducing. During mining, most of the original water is extracted by pumping to keep the mine dry. Pumping exposes the coalbearing rocks to moist air, leading to oxidation of pyrite within the sequence, helped by the catalytic action of bacteria.
When mines close and pumping stops, the water table can rise again. Soluble products of pyrite oxidation will pollute groundwater with sulphuric acid, iron and manganese cations, sulphate anions, and sometimes highly dangerous arsenic ions.
A solution to water pollution is not easy to find. Continued pumping after a pit has closed down is expensive, and routing polluted mine waters into special treatment areas is impractical because it is almost impossible to predict the movement of groundwater in anything other than general terms.
Environmental scientists have looked at other ways of improving the quality of mine waters, such as the use of wetlands in which some plants can permanently absorb pollutants, and neutralizing mine waters by adding alkaline calciumcarbonate or sodium hydroxide. Neutralization also decreases the solubility of dissolved metal ions, so that they precipitate and settle out of solution.