Application of cement-sodium silicate mixed grout in control of water and sand bursting from roof of the working face

Water and sand bursting in roof occur repeatedly in the East, North and Northwest China, and threatens the mine safety. Based on the idea of "artificial false roof" rebuilding in the area of water and sand bursting, we put forward use of the cement-sodium silicate mixed solution with rapid solidification to plug the channel. An event of water and sand bursting in the upper coal seam of a Jurassic coal mine located at the western margin of the Ordos basin was selected, and we formulated a ground control scheme for the cement-sodium silicate grouting through the two slurry parallel tubes separately, and mixing in the bottom of the hole. Based on the data of drilling and grouting, the spatial shape of the zone with sand bursting and the grout were presented as a saddle, and a semi-ellipsoid with local bulge, respectively. After the completion of project, the comprehensive index formed by the dynamic characteristics of water head in water-filled aquifer, variation characteristics of the groundwater flow field and characteristics of transient electromagnetic resistivity, indicates that the bursting channel was completely blocked. The conclusion provides the new plugging and evaluation techniques for the similar project.