Surrounding Rock Control And Security Technology Research On Old Residual Coal Mining Longwall Mining

Coal is one of the most important energies in the long-term development of China and it holds a possession of70%to75%in the primary energy consumption of China. What’more, China will keep the pattern of energy production and consumption that is based on the energy of coal in the future. With the exploitation of coal resources unceasingly, the amount of good-quality coal resource in China is less and less.But, there are a lot of coal resources left in the mine that has been picked, especially for the destruction of the small coal mine resources, the rate of most mine recovery is less than30%. After calculation, the amount of residual of coal resources is26.3billion tons only in Shanxi prominence. It is the most urgent needs for the coal industry to think about how to solve this difficulty of residual of coal resources, how to improve recovery rate.This paper takes the residual coal area of No.6coal seam in Rui Long coal mine in Jin Zhong City and applies the method of theoretical analysis, field observations and numerical simulation,to explore abutment pressure in the distribution the old mining residual coal zone, and to explore technology of the wall rock control, the main works are as follows:1. The study analyzed six kinds of factors why the resources of residual coal mine coal exist. And it classifies these factors according to mining technical conditions of residual coal mine. According to assessment formula of recoverable coal resources, it indicates the method of calculation of the residual coal resources. In addition, it shows economical evaluation of coal residue resources for No.6of Ruilong Mine.2. Taking the Rui Long coal mine as an example, I pose four problems of supporting-pillar after the method of old room and pillar mining during research of the characteristics of the coal district of the old mining residues. Through the theoretical analysis of the supporting roof force on a single coal pillars, the study presents that the stress concentrates in the middle of the coal pillar and the greatest force is also in the middle of the coal pillar. Through theoretical analysis of supporting roof force of coal pillar group, the study presents that the roof stress concentrates in the free zone. After the study of width of coal pillar,9meters of coal pillars can support the roof steadily.3. After the numerical simulation experiments for the solid coal and residual coal (regular or irregular pillar,) through the RFPA Software, and after the analysis and comparison of coal pillars before the working face, the paper concludes:while the width of coal pillars becomes smaller gradually in the zone of residual coal mining, the pressure step in the working face becomes smaller, at the same time, the supporting pressure peak before working face, the peak position, peak range, and the stress of coal pillar before working face20M are all become bigger accordingly.4. After the analysis of arrangement for the trough of working face in Ruilong Mine, the study concludes if the mine is used to the existing roadway, it can save production cost and shorten the production time. However, if the cross-section of roadway becomes large, the roadway is difficult to maintain. It costs much time and cost to retrench roadway which is relatively easy to support.5.Through the theoretical analysis, we can determine support resistance and frame type in the working place.6. This paper researches and studies the security technology of the roof, water, gas after the residual coal mining long wall.