A method for mining an ultra-thick coal seam by utilizing a goaf solid backfilling technique is suitable for mining an ultra-thick coal seam having a thickness of 25 m-45 m. According to the method, the ultra-thick coal seam is sliced into three slices, i.e. an upper slice, a middle slice and a lower slice. First, the middle slice is subjected to solid backfilling and mining. Metal meshes are paved along a working face of the floor. The backfilling layer serves as an artificial floor for mining the upper slice and an artificial roof for mining the lower slice. Then, the upper slice is mined by the top coal caving mining based on the artificial floor formed by backfilling the goaf of the middle slice. Finally, the lower slice is mined by the top coal caving mining along the coal seam floor with the shield of the artificial roof.

A method for mining an ultra-thick coal seam by utilizing a goaf solid backfilling technique is suitable for mining an ultra-thick coal seam having a thickness of 25 m-45 m. According to the method, the ultra-thick coal seam is sliced into three slices, i.e. an upper slice, a middle slice and a lower slice. First, the middle slice is subjected to solid backfilling and mining. Metal meshes are paved along a working face of the floor. The backfilling layer serves as an artificial floor for mining the upper slice and an artificial roof for mining the lower slice. Then, the upper slice is mined by the top coal caving mining based on the artificial floor formed by backfilling the goaf of the middle slice. Finally, the lower slice is mined by the top coal caving mining along the coal seam floor with the shield of the artificial roof.

A plug for a void in a mine to divert water having a rigid closed cell foam which fills the void. The rigid closed cell foam having a plurality of pipes disposed within the foam. The pipes distributed throughout the void. The pipes are positioned in the foam so the pipes are staggered in length vertically with respect to various heights in the void, and the pipes are positioned in the foam every 4 to 6 horizontally with respect to the void. A method for diverting water from a void in a mine.

A fluidized coal mining method for implementing CO.sub.2 underground storage, includes mining area division, tunneling mining, filling and supporting, roof and bottom plate sealing, and boundary surrounding rock sealing. A goaf formed by a mining device after tunneling and mining along a mining strip is filled and supported, and filling and supporting can form a high-strength supporting wall body, which not only provides an effective supporting effect for roof and bottom plate rocks, but also forms a filled and supported wall body; a space for underground storage of CO.sub.2 is formed between adjacent filled and supported wall bodies; at the same time, the mining device further seals the roof and a bottom plate of the goaf, and seals boundary surrounding rocks of a mine field, so that the entire mine field forms a whole closed space for the underground storage of CO.sub.2 after mining is completed.

A plug for a void in a mine to divert water having a rigid closed cell foam which fills the void. The rigid closed cell foam having a plurality of pipes disposed within the foam. The pipes distributed throughout the void. The pipes are positioned in the foam so the pipes are staggered in length vertically with respect to various heights in the void, and the pipes are positioned in the foam every 4 to 6 horizontally with respect to the void. Each pipe has a mixing stick. A method for diverting water from a void in a mine.

The present invention relates to method for filling deformable karst cave, and the steps are: penetrating a grouting pipe into an elastic silicone tube, penetrating the grouting pipe and the elastic silicone tube into a deformable bracket, and lowering into a karst cave; sealing the elastic silicone tube, injecting silicate resin materials into the grouting pipe, and injecting steel fiber reinforced grout to implement a block stone-like structure; sealing the elastic silicone tube, separating the block stone-like structure from the elastic silicone tube to complete a block stone-like structure; lowering the elastic silicone tube and the deformable bracket, sealing the elastic silicone tube, lowering the elastic silicone tube and the deformable bracket tore construct the block stone-like structure, and completing the filling. The present invention may effectively stabilize the karst cave, ensure safe tunnel construction and stable surrounding rocks, and improve engineering construction speed.

A plug for a void in a mine to divert water having a rigid closed cell foam which fills the void. The rigid closed cell foam having a plurality of tremie pipes disposed within the foam. The tremie pipes distributed throughout the void. The tremie pipes are positioned in the foam so the pipes are staggered in length vertically with respect to various heights in the void, and the tremie pipes are positioned in the foam every 4 to 6 horizontally with respect to the void. Each tremie pipe has a mixing stick. A method for diverting water from a void in a mine.

A method for dynamic water feeding and hole sealing using high water-absorbent resin is applicable to sealing of a borehole on which extraction has a great impact. Two ends of a hole-sealed section of the borehole are sealed. Fine mixed high water-absorbent resin powder wrapped in a piece of cotton cloth is disposed in the hole-sealed section of the borehole, a water injection pipe and a gas extraction pipe are inserted in the borehole, and an automatic feed water valve is used to inject water into the hole-sealed section. The fine mixed high water-absorbent resin powder that fills the hole-sealed section and surrounding cracks with the water flow rapidly swells up after soaking up water to fill the hole-sealed section, and maintains at a swelling pressure. After the powder swells up and hole sealing is completed, the extraction pipe is connected to an extraction apparatus to perform gas extraction. This method has advantages such as tight hole sealing, high automation degree, and dynamic hole sealing, thus effectively solving problems that pores around the borehole are poorly sealed, it is difficult to seal cracks newly produced by extraction and so on. Moreover, the powder for hole sealing is low in price, and therefore the hole sealing cost is low.

The present invention provides for a compressible grout mix for filling an annular gap between a tunnel rock wall surface and a tunnel liner of a tunnel in a rock formation subject to time dependent deformation after excavation and a method of filling the annular gap between a tunnel rock wall surface and a funnel liner of a tunnel in a rock formation subject to time dependent deformation after excavation utilizing the compressible grout mix for resilient absorption of forces in the hardened state of the compressible grout mix exerted by the time dependent deformation of the rock wall surface into the tunnel opening. The method includes: a. providing a compressible grout mix comprising hydraulic binding agent, bentonite clay, polymer foam particles, water, and one or more additives selected from water-reducing admixture and/or setting retarding admixture, aggregate materials, anti-wash agents and air, b. placing the compressible grout mix in the annular gap between the tunnel wall rock surface and the tunnel liner, and c. allowing the compressible grout mix to set, wherein the compressible grout mix in the hardened state has a compressible ratio greater than the anticipated time dependent deformation.

The present invention provides for a compressible grout mix for filling an annular gap between a tunnel rock wall surface and a tunnel liner of a tunnel in a rock formation subject to time dependent deformation after excavation and a method of filling the annular gap between a tunnel rock wall surface and a funnel liner of a tunnel in a rock formation subject to time dependent deformation after excavation utilizing the compressible grout mix for resilient absorption of forces in the hardened state of the compressible grout mix exerted by the time dependent deformation of the rock wall surface into the tunnel opening. The method includes: a. providing a compressible grout mix comprising hydraulic binding agent, bentonite clay, polymer foam particles, water, and one or more additives selected from water-reducing admixture and/or setting retarding admixture, aggregate materials, anti-wash agents and air, b. placing the compressible grout mix in the annular gap between the tunnel wall rock surface and the tunnel liner, and c. allowing the compressible grout mix to set, wherein the compressible grout mix in the hardened state has a compressible ratio greater than the anticipated time dependent deformation.