نتایج جستجو برای: mining coal mining
تعداد نتایج: 114364 فیلتر نتایج به سال:
China is the world’s largest coal-producing country and mining-related land subsidence happens almost in every coal mining area. In north-west China, land subsidence in coal mining areas is mainly caused by underground mining activities and uncontrolled burnings of subsurface coal seam. As Hoffmann (2004) reported, burning coal-seams can result in extensive subsidence of several meters and typi...
Mining and logging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 854 876 881 882 883 890 7 Logging.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1133 49.9 52.9 53.2 55.2 54.4 54.1 -0.3 Mining. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 803.7 ...
China produces and consumes most of coal in the world. This situation is expected to continue within a certain period in the future. Currently, Chinese coal industry is confronted with several serious problems relating to land resource, water resource, environmental, and ecological sustainability. Coal resource exploitation causes the permanent fracture and movement of strata structure, which h...
Subject analysis of the potential of spontaneous combustion in coal layers with analytical and numerical methods has been always considered as a difficult task because of the complexity of the coal behavior and the number of factors influencing it. Empirical methods, due to accounting for certain and specific factors, have not accuracy and efficiency for all positions. The Rock Engineering Syst...
The key to the safe mining of thick coal seams under rivers is understanding the development patterns of fractured water-conducting zones (FWCZ) when various mining methods are used. To solve this problem, we employed numerical simulation to investigate FWCZ when slice mining and longwall caving mining are performed. When slice mining was carried out, the maximum height of the FWCZ in the highe...
subject analysis of the potential of spontaneous combustion in coal layers with analytical and numerical methods has been always considered as a difficult task because of the complexity of the coal behavior and the number of factors influencing it. empirical methods, due to accounting for certain and specific factors, have not accuracy and efficiency for all positions. the rock engineering syst...
the first step in mining activities is rock excavation in both mine development and production. constant pressure for cost reduction and creating an improved/safe work environment for personnel has naturally resulted in increased use of mechanical excavation systems in many mining operations. also, mechanical excavation and mining is more compatible with automation, meaning possibility of reduc...
PURPOSE To determine if chronic cardiovascular disease (CVD) mortality rates are higher among residents of mountaintop mining (MTM) areas compared to mining and nonmining areas, and to examine the association between greater levels of MTM surface mining and CVD mortality. METHODS Age-adjusted chronic CVD mortality rates from 1999 to 2006 for counties in 4 Appalachian states where MTM occurs (...
Coal is an important fossil fuel and will also be for the next decades [1]. The only way to achieve the challenges faced by the coal industry is to reduce production costs by improving productivity. Improvement of productivity has become an important goal for today’s coal industry in the race to increase price competitiveness. In recent years, underground mining method is becoming popular becau...
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