Method for recovering coal resources in upper adjacent layer and reducing stress concentration of upper adjacent layer

Abstract

The invention discloses a method for recovering coal resources in an upper adjacent layer and reducing stress concentration of the upper adjacent layer, and belongs to the technical field of mining industry. By omnidirectionally recovering the abandoned coal resources in the upper adjacent layer, an immediate roof of the upper adjacent layer is integrally sunken, an overlying key block tends to begentle, the original overlying loads concentrated on the abandoned coal resources are jointly borne by residual coal resources and stereotaxis gangue in goafs on the two sides, the stress concentration phenomenon is greatly reduced, and rock burst is prevented; the large deformation phenomenon of a roadway roof and surrounding rock is completely eradicated, and thus deformation of the surroundingrock of the working face roadway is controlled to be in the safe, reasonable and supportable range; the phenomenon of large-area roof weighting of the working face roof due to the fact of passing thelower part of residual coal pillars in the promoting process of a stope face is prevented; and thus safe mining of a lower coal seam is ensured.

Description

technical field [0001] The invention belongs to the field of mining technology, in particular to a method for recovering coal resources in an upper adjacent layer and reducing the stress concentration thereof. Background technique [0002] Double coal seam and multi-coal seam mining areas are widely distributed in Xinjiang, Inner Mongolia, Shanxi, Shaanxi and other provinces in China. Coal seam group joint mining is widely used in various mining areas with double coal seams and multi coal seams due to its safety, economy, and high efficiency. In the process of joint mining of coal seam groups, the downward mining method is generally adopted, that is, the upper coal seam is mined first, and then the lower coal seam is mined. Mining the overlying coal seam first has the following advantages: [0003] (1) The mine can be put into production in a relatively short period of time and can better provide economic support for the mining of the mine. [0004] (2) The overlying coal...

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Problems solved by technology

[0007] (1) Strengthening the support of the working face of the lower coal seam only changes the mechanical properties of the surrounding rock of the working face, but does not eliminate the generation and transmission of high concentrated stress in the coal pillar left over from the overlying coal seam, the phenomenon of large-area pressure on the roof, and the impact of the ground The risk of pressure still exists

[0008] (2) Drilling to relieve pressure on the coal wall of the lower coal seam can only release the high concentrated stress through the drill hole, but cannot eliminate the generation and transmission of high concentrated stress in the coal pillar left over from the overlying coal seam, and it will affect the coal wall of the mining face Drilling will affect the normal advancement of the working face, resulting in reduced mine production

The remaining coal pillars in the upper adjacent coal seam still exist intact, and the remaining coal pillars will still generate high concentrated stress, and the high concentrated stress generated by the surrounding rock above the remaining coal pillars will still be transmitted through the remaining coal pillars, so strengthening the support or drilling Pressure relief cannot completely solve the problems of large deformation of roadway surrounding rock, large area of ​​roof pressure and rock burst in the mining process of lower coal seams.

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