Development of non-coagulable grout long-term sealing material for gas drainage

Abstract

Gas is produced during coal formation and is a major threat to the safety of coal mining operations. Gas-related accidents, including gas explosions and coal and gas outbursts, are particularly dangerous. However, gas also has great potential as a clean energy source. Therefore, effective gas extraction is essential for preventing accidents and utilizing its potential. The sealing material used for gas extraction boreholes directly affects the quality of the seal and, consequently, the efficiency of gas extraction. To address the limitations of cement-based and polyurethane sealing materials, this paper presents a novel non-coagulant long-term sealing material. Firstly, the optimal material ratio was determined through experiments involving constant temperature and weightlessness. The optimum proportion of modifier to be added is obtained by constant temperature weight loss experiments. Secondly, microscopic analysis revealed that the modified component was effectively inserted into the group. To simulate the underground gas extraction conditions in coal mines, drainage and plugging experiments were designed. The results showed that the new material had a 100% plugging performance during the observation time, while the plugging performance of cement-based and polyurethane sealing materials significantly decreased under the same experimental conditions. Finally, the non-coagulant long-term sealing material was applied in the gas drainage experiment of tunnel 53081 at Changping Coal Mine. Compared to the original cement-based sealing material, the gas extraction concentration of the borehole increased by 16.5%. These results suggest that the newly developed sealing material is suitable for gas extraction and has significant potential for practical application.