外文原文-动压作用下软岩巷道围岩控制综述.doc

1、中国矿业大学2005届本科生毕业设计 第126页 Why Longwall in India has not Succeeded as in other Developing Country Like ChinaProf A K GhoseAbstract Of the global hard coal production of some 3300 million tonnes during 2000-2001, China headed the league table with a production of 970 million tonnes, and with a producti

2、on level of 320 million tonnes India ranked third. Both of these developing nations have large resource endowment in bituminous coal, the proved recoverable reserves at end 1999 stood at 114500 million tonnes in China and at 84396 million tonnes in India according to Survey of Energy Resources 2001

3、of the World Energy Council1. Coal occupies the centre-stage in the energy economy of both the nations, coal has a share of 75% of the consumption of primary energy in China while in India the share of coal is around 64% in the current mix of commercial energy2. However, any comparison between the t

4、echnology levels of the two giant nations in coal production would perhaps be invidious, dictated as these are by a whole host of imponderables including the site-specific conditions of the resource endowment, differing thrusts of national policy and the socio-cultural and political milieu. Undergro

5、und coal mining has a predominant share of some 94% of Chinese coal production, while in India the share is only 21%. To examine and analyze the palpable reasons for not so successful application of Longwall technology in India vis-a-vis China, one needs to examine the chronological evolution of the

6、 technology in the two nations, appraise the technogenesis of Longwall technology in both the countries and then home in on the contributory factors. This paper attempts a foray in unravelling the reasons fully cognizant of the fact that any post hoc analysis, as of date, can only outline a hypothes

7、is of the multitude of reasons behind the apparent failure of Longwall technology in India due to subjective interpretation and perception of the issues involved. It is also not always possible to reflect by hindsight on the compulsions of the planner/decision-maker in choosing a specific strategy a

8、t any given point of time. Be that as it may, we examine here on a broad canvass the remarkable saga of growth in Longwall technology in China and the apparent under-performance of Longwall in India.Keywords Longwall, Geotechnology, Moonidih colliery, Coal seamsLONGWALL TECHNOLOGY GENESIS AND EVOLUT

9、IONFigure 1 Longwall tons (st) per 8-h machine shift (annual average for a single mine) since 1984The seventeenth century innovation of Longwall system in Shropshire in England has made giant strides over the past three centuries to emerge as the predominant bulk production system in global coal ind

10、ustry today with a share of nearly 70% of the aggregate production and is recognized as the safest, the most productive and cost effective method as well for extraction of coal seams by underground mining3. Longwall mining made its debut in Indian coal mining scene reportedly around 1870s; despite s

11、uch head start however the progression of the technique in Indian coal industry milieu has been extremely slow and halting. From the early application to stowing faces, caved Longwalling was attempted only around early 1960s and the first mechanized powered support face, the new-age Longwall, was la

12、unched in August 1978 at Moonidih Colliery. While this marked the beginning of a major initiative in transfer of innovative Longwall technology in the relatively low technology milieu of Indian coal industry, the overall performance has fallen short of expectations and despite experiences in deployi

13、ng some 33 mechanized powered support packages to date in Coal India and Singareni Collieries Company, Longwall technology in India remains a laggard, straggling miles behind the global best practices. One could cite the case of Console Energy which operated 14 Longwall mining systems of the 59 oper

14、ating Longwalls in the United States in 2000, where the best Longwalls annual production average is close to 8100 clean tonnes per 8-h machine shift. Figure 1 shows the evolution of Longwall tons (short tons) per 8-h machine shift (annual average for single console mine) since 19845. There are examp

15、les galore of such high performance faces in the United States, Australia and even in China. In benchmarking the performance of Indian Longwall faces with those of China, it is necessary to examine the evolution of coal mining technology in India and China to provide a backdrop. India gained Indepen

16、dence in 1947 and commenced on the national economic planning journey in 1951. China as a nation-state came into existence in 1949 when its coal output was 32.43 million tonnes, very close to Indias coal output.While both the nations started almost at the same base level, Chinas coal odyssey has been marked by a quantum jump in production level which touched an all-time high of 1.3 billion tonnes in 1997 encompassing the three elements of the coal