Improvement and Application of Bedding Borehole Sealing Method

Basing on the extraction result of bedding borehole at 8101 working face, we found the reason that poor sealing quality cause poor extraction effect. By improving the original method of sealing drainage hole, three kinds of sealing methods (polyurethane sealing, grouting around the coal cracks on the basis of polyurethane sealing and quick-setting cement-polyurethane combined) were proposed and then conducted. The test results show that the quick-setting cement-polyurethane combined method can effectively improve the sealing extraction parameters of bedding drainage borehole, it is better than the other sealing methods. Finally, the reason why grouting around the coal cracks on the basis of polyurethane sealing can not effectively improve the extraction efficiency is discussed briefly.