Application of long-distance pre-grouting technology in a coal mining face with large cutting height

Coal face with large cutting height is popular in the coal mining industry because of dramatic productivity and efficiency. The coal wall slab problem of the coal wall slab problem of the large mining face seriously hindered the efficient and safe production of the mine. To solve this problem, a long-distance pre-grouting material and a new double-liquid borehole sealing material were proposed, and based on the research on the performance of grouting material, the ratio optimization was carried out. In addition, the related long-distance pre-grouting technology including drilling arrangement and sealing was proposed. Results indicate that final proportions for the long-distance grouting material among superfine Portland cement, composite retarder, composite early-strength admixture, and water cement ratio are 100%, 2%, 2%, and 0.6:1, respectively. For the double-liquid borehole sealing materials, the mixing amounts of the composite retarder A and composite retarder B are 0.5% -1.0% and 1%, respectively, and the water cement ratio is 1:1. And the industrial experiments show that the stability of the coal wall is significantly improved, and good economic benefits is achieved. This study provides a significantly guidance for the application of long-distance pre-grouting technology in coal mining face with large cutting height practical engineering. © 2019 Eastern Macedonia and Thrace Institute of Technology.