英文读写literature review范文.doc

the influence of mining exploitation on environment and the solution of the disposal of solid waste residue by the year of 2012, china has 8557 state-owned mining enterprises and over 200 thousands individually owned enterprises. the area of destroyed land in mining area adds up to 29 thousand km2 and grows at the rate of 2% each year (liao l-p, gao.h and yu x-j, 2012). the mining industry has scored tremendous achievements, but meanwhile it threatens the environment. some individually owned enterprises lack the awareness of environmental protection and take no preventive measure to lower their cost. furthermore, out-of-date equipment and poor technology cause huge waste in production, which cause serious environmental pollution. the destruction on land resourcesstrip mining and the piling of tailings and waste residue occupies and destroys large land. in china, the waste-occupied land in mining area adds up to 59 thousand km2 and the resulting deforestation area adds up to 11 thousand km2 (ma x-q, huang b-l, 2010). strip mining can result in the destruction of land surface and land subsidence and accelerate the water and soil losses. according to official statistics, by the year of 2011, in the mining area of western china, the soil erosion area annually increases 20 km2.the increase of the risk of geological disasterthe construction of mining engineering can significantly change the landform in mining area. digging to a certain depth will threaten the stability of hillside and easily induce some geological disasters, such as landslip, collapse, debris flow, surface subsidence and even earthquake (cao f-g, 2007). for example, 4 tons of water will be drained off when 1 ton of coal is mined. the loss of groundwater exerts huge pressure on earthcrust (gibowicz, 1999). in china, there are nearly 2000 sinkholes and the collapse area adds up to 1150 km2. almost 40 of the mining cities in china have cave-in accident, which threatens the life of mine operators and cause heavy property loss, about 120 million dollars on average each year.the influence on water resource deep mining engineering will influence the surface water resources and groundwater resources. excessive groundwater extraction can cause the drop of water level, some problems on water supply and land subsidence (auclair ad, 2008). the quality surface water will decrease and the course of river might be changed. in some drought region，the drop of groundwater level can lead to the death of land vegetation (becker m, 2005). more seriously, huge amounts of industrial water are required to support over exploitation in mineral-abundant region and most of the water is drawn from agricultural water, which interferes the agricultural production (shi x-h, 2009).the loss of biodiversity soil degradation, environmental pollution, the emission of waste and vegetation clearing are fatal to the biodiversity in mining area. after the loss of biodiversity, some high-resistant species can still inhabit the abandoned land in mining area, but because of the barren soil and the deficiency of microorganism activity, the recovery of ecosystem usually need 10-50 years (xiao h-l, 2011). the loss of biodiversity in some damaged ecosystems is even irreversible.the solution of the disposal of solid waste residuesolid waste residue is the biggest polluter in mining area and the disposal of it still plagues the government and mining enterprises, so it deserves a separate discussion. the heavy metal ion in solid waste is the most harmful substance. once contacting water source, these ions will dissolve, making the water corrosive and toxic, and it is very difficult to extract them from the water (fao, 2004). high technology offers two new methods to solve this problem. one is microorganism technology. the removal of heavy metal ions by microorganism is a new applicable technique. various types of biomass, including bacteria, fungi, yeast and algae have been evaluated for their heavy metal uptake properties. the most prominent features of biosorption are the use of low cost biomass material and the high efficiency of some biomass to uptake heavy metals in very low concentration (jose t.matheickal, 2001). another one is new corrosion-resisting clay. this kind of clay is toughened, innocuous and environmental-friendly. in the process of disposing the waste residue, the clay will be first made into mud. the clay mud covers the surface of waste residue and after it dries out, the clay will become a waterproof layer and can resist the corrosion of any substance in the soil. then the waste residue can be sequestered underground safely (moore, 2005).however, zhu.j.j has pointed out the possible resistance of the implementation of these methods. there is a lack of related professional staff. disposing the waste residue in high-tech methods will increase the cost of enterprises (zhu j-j, 2009). whats more, some individually-owned enterprises are even ignorant of the importance of environmental protection, so they may be completely uninterested in these handling methods .summary and tipsalong with the enhancing of the peoples awareness of the environment，the environmental management has become indispensable in the development of mining industry. some relative rules, regulations, and standards show be put on to establish a more rational working mechanism. if the development condition of the mining industry improves, the mining enterprises will no longer pursue profit at the cost of environment.referencesauclair ad. (2008). a case stury of forest decline in western canada and the adjacent united states. water, air and soil pollution 53(2): 23-31.becker m. (2005). silver fir decline in the vosges mountains: role of climate and natural culture. water, air and soil pollution 48: 77-80cao f-g. (2007). hunan geology science & technology 21(2): 29-31(in chinese)fao. (2004). state of the worlds chemical industry, 2009. journal of applied chemistry, 15(10): 195-196gibowicz. (1999). magnitude and energy of subterranean shocks in upper silesia. the earths interior structure 32(7): 14-15jose t.matheickal. (2001). removal of heavy metal ion from wastewater by using biosorbents from marine algae. chinese journal of chemistry 9(2): 133-136liao l-p, gao h, yu x-j (2012). chinese journal of applied ecolog