Test Study On The Law Of Drawn-out Body Of Top Coal In Fully-mechanized Top Caving Face In Steeply Seam

Coal is the main energy in China, where has an acquired reserve of 7.2 billion tons. It will account for 50% of China's energy structure in the first five decades in the 21st century. However, the safety and efficiency have been the two hard nuts to crack for China's coal exploiting industry. Since 1980s, China's coal mining industry started to adopt the fully mechanized mining caving technology that has improved the safety and efficiency in the thick coal bed. The technology now has become the mainstream. There is a lot of steeply dipping seam more than 35o in western China. More than 50 per cent of coal mines in western areas are steeply dipping seam. Coal has become the economical pillar in western China, as the Chinese Government switches its focus from eastern areas to the west. So it is meaningful to do a lot of researches on tilt coal bed exploitation. In eastern mining area, fertile coal beds have been turning to be lesser and lesser because of years' exploitation. Along with increasing mining intensity, Exploitations in tilt coal bed have turned to be a problem that needs to be solved in the process of sustainable development. The exploitation technology at present is far worse than that of the flat-pitching seam, and it has still huge differences with exploitation of steeply dipping seam and horizontal seam. It's more difficulty and has more risks in this process. In the process of exploiting steeply dipping seam by the traditional non-mechanization method, there are a lot of pole-collapse incidents, which result in a great deal of potential safety hazard. So the traditional non-mechanical methods can't meet the security demand when exploits steeping dipping seam. In the process of exploiting steeply dipping seam, it's a trend to adopt mechanization with higher security degree and efficiency. This article divides the caving top coal on the working face into four areas of compaction area,full fill section,partial backfilling section and prop-free section. It also includes researches on the form of caving top coal.