Preparation and Application of New Sealing Material for Blasting

For the weaknesses of long coagulation time, poor liquidity, low early strength of current sealing material used in coal mine blasting, based on Portland cement and common admixture, the optimal components were screened and analyzed by comprehensive test, and the mechanical property test and field test were carried out. The conclusion indicates that: when the mass ratio of NaAlO₂ is 2.5%, CaCl₂ is 1.5%, TEA is 0.03%, water reducer is 0.5%, the initial setting time of the compounded material extends to 33 min, the final setting time extends to 62 min, the 2 h static compress strength reaches to 0.81 MPa, and dynamic compress strength reaches to 3.12 MPa. Meanwhile, compared with common cement, the compounded cement sealing material has a better sealing performance and adaptability, the setting time is reduced from 10 h to 2 h, and the purity of the extracted gas is improved by 8.6%, the blasting progress and productivity is greatly strengthened.