Research On Top-coal Breaking Mechanism And Recovery Ratio In Fully Mechanized Top-coal Caving Face Of Gongwusu Mine

The fully mechanized top-coal mining is one of the main methods of our countryexploiting the thick and favoring a coal seam specially. The top-coal recovery ratio is lowof the main problem in full mechanized top-coal caving face, and improving the fullymechanized top-coal recovery is of great significance to the high output and highefficiency of the coal mine in china. This paper is based on actual situation of No.1604coal face in gongwusu coal mine of Wuhai, researching the top-coal breaking mechanismand caving and drawing characteristics. This paper is based on predecessor’s research dataand proposes the technical measure to increase the top-coal recovery ratio by using coaland rock sample mechanics experiment, theories analysis, numerical simulation andpressure observation.First, through the geological data collection from the1604working face and coalsample mechanics experiment, obtain coal and rock mechanical parameters. Second,analyze the breaking mechanism of top-coal, caving and drawing characteristics and theinfluence factors of top-coal recovery ratio. Based on the analysis of main factorsinfluencing the top-coal breaking, such as mining depth, coal intensity, support resistance,coal seam thickness, structural surface, the paper indicate the top-coal failure mechanism.Combined on the result of mechanical experiment, considered on the six factorsinfluencing on top coal caving and drawing characteristics, such as coal intensity, miningdepth, coal seam thickness, roof fissuring and cracks, coal bed dirt layers, roof rockcharacters and so on, the paper obtained the16#coal caving and drawing characteristicsvalue of0.36, it is good at top-coal mining by using fuzzy mathematical method evaluationdata of each factors. Based on the analysis of main factors influencing the top-coalrecovery, such as do not mining at the begin of the working face and at the end of theworking face, working face design and equipment complete is wrong, productionmanagement, technological parameter mismatching, put forward targeted measures. Third, the top-coal recovery ratio is well when ratio between mining and dropt is1:2.54, coalcaving step distance is0.6meter, coal saving mode is several rounds of the order byaccording to the basic theory of top coal caving, studying caving process parameters(mining height, dropt of coal caving height, ratio between mining and dropt, coal cavingstep distance, coal saving mode), combined on numerical simulation.Finally, put forward specific technical measures according to No.1604fullymechanized top-coal caving face in gongwusu coal mine. When put it into field application,analyzed production and top-coal recovery for five consecutive months. The resultsshowed that coal output every month up to the136283t and coal output every day up to the5678.5t and the best top-coal recovery ratio is86.7%. Not only reduced enterpriseproduction cost greatly, improved the treatment of employees and living standards,meanwhile, played an exemplary role to the rapid development of local economy. In theprocess of mining promote the development of the caving mining technology in Chinabecause of accumulated valuable experience.