Disastrous Mechanism and Concentration Distribution of Gas Migration in Fully Mechanized Caving Stope in Wuyang Coal Mine

Abstract

The overrunning disaster of harmful gas tends to occur in the working face in thick coal seam with high gas concentration, as the fully mechanized caving stope has the characteristics of high mining intensity, high remnant coal, and high gas content. Therefore, the disastrous mechanism and concentration distribution of gas migration in fully mechanized caving stope are the theoretical basis for gas control scheme. Based on the 7607 working face in Wuyang coal mine, the gas emission quantity in working face is comprehensively analyzed by field measurement in this paper. The gas leakage field, oxygen concentration field, and gas concentration field in 7607 working face are simulated by establishing the equal proportional numerical model. Due to the increase of air leakage in working face caused by the high alley pumping drainage, the risk of coal spontaneous combustion is also analyzed, when gas extraction in goaf is carried out. The research results show that the gas drainage technology in high drainage roadway has a remarkable effect on the gas overrunning phenomenon. The gas concentration near the upper corner of the working surface has been reduced from 0.7%-1% to 0.5%. At the same time, it is necessary to pay attention to the risk of coal spontaneous combustion in the goaf for gas drainage in the high drainage roadway. The width of the oxidation zone in the goaf is about 25 m deeper than that before the drainage. Research results provide the references for gas control technology and coal spontaneous combustion prevention in similar working faces.

Optimization and Investigation of Rapid Sealing Technology Based on Mine Disaster Period

“…When conducting fire rescue underground, if the fire cannot be directly extinguished within 1-2 h of development, there is a risk of gas explosion in the disaster area with sufficient oxygen. From this perspective, it is necessary to quickly and effectively establish underground enclosed facilities to isolate the disaster area and reduce oxygen supply to prevent further expansion of the disaster [4][5][6][7]. Thus, rapid sealing technology is a practical disaster relief technology that can be used in disaster areas to effectively control the oxygen supply in fire areas.…”

Gas Emergence Characteristics of the Upper Corner on the 215101 Mining Working Face of the Yue Nan Coal Mine

“…Through gas extraction in the gob, the gas concentration in the gob can be reduced, which can effectively prevent the gas over limit in the upper corner of the working face. In order to prevent the upper corner gas over limit, some scholars have analyzed the upper corner gas concentration and the gas concentration in the gob on the working face under different extraction positions, , extraction volumes, , and extraction angles through numerical simulations , and field measurements and selected the optimal extraction position and compared the upper corner gas concentration and the gas concentration in the gob before and after extraction, which proved that the extraction can better solve the problem of gas over limit in the upper corner of the working face and has a significant effect on the gas management in the gob. From the above research, it can be seen that the results obtained by field measurements and the results obtained using numerical simulation software are in good agreement for mine gas research.…”