A method of cracking the left filling wall of adjacent coal mining face

Abstract

A method for fracturing a filler wall left behind in an adjacent coal-mining face, applicable in continuous pressure-relief mining of a coal seam group at a great depth. A drill hole (2) distribution scheme, parameters, and a volume of an explosive charge are designed on the basis of the size of a filler wall (1), a construction scheme for same, and a state of earlier damages of same; one to three rows of downward tilted drill holes are constructed by an advancing coal-mining face (3) on a filler wall left behind and reused by an adjacent coal-mining face (4) in a tunnel; one to two rows of the drill holes in the rear within an extremity hydraulic frame (6) are filled with the explosive charge and sealed; as the coal-mining face advances, the drill holes filled with the explosive charge in the rear within the extremity hydraulic frame enter the rear side of the coal-mining face, microcracks on the filler wall caused by earlier mining pressure are utilized to intensify cracking of the filler wall, and, combined with the effect of a lagging mining-induced stress, the filler wall left behind is ultimately fractured. The method allows fracturing of the filler wall left behind in a goaf by the adjacent coal-mining face, thus effectively eliminating an effect of stress concentration posed by the filler wall to upper and lower adjacent coal seams, implementing the goal of continuous pressure relief, and solving safety risks of adjacent coal seam mining.

Description

technical field [0001] The invention relates to a method for cracking the left filling wall of an adjacent coal mining face, and is especially suitable for continuous pressure relief mining of deep coal seam groups. Background technique [0002] Gobside retaining is to build a wall with a certain bearing capacity along the edge of the goaf, and retain the mining roadway of the adjacent coal mining face for use as the mining face of the coal mining face. It is one of the key technologies for continuous pressure relief mining of deep coal seam groups, and it is used to solve safety problems such as rock burst, coal and gas outburst, high gas, and high ground pressure. [0003] At present, it is more and more common to use cement-based materials to construct gob-side retaining walls, especially in deep mining areas. The cement-based walls are quick-setting and early-strength, supplemented by reinforcement methods such as shear anchors and three-dimensional reinforcement ribs, ...

AI Technical Summary

Problems solved by technology

Although the cement-based wall has micro-cracks induced by the two mining operations, it still continues to increase resistance and cannot self-destruct the bearing capacity. A concentrated stress zone is formed in the upper and lower adjacent coal seams, which cannot achieve the purpose of continuous pressure relief. is a potential safety hazard for adjacent coal seam mining

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