Completely non-coal pillar continuous pressure relief mining method for close-distance coal seam groups

Abstract

A complete non-coal-pillar continuous depressurized mining method for a short-distance coal seam group, which is applicable to a coal mining project. The method comprises: determining the mining sequence of coal seams in a coal seam group; when a first coalface (1) of a first mined coal seam is mined, building a filling-wall (11) in which a breather pipe (10) is disposed along the edge of a goaf, so as to form a gob-side entry retaining (12); taking the roadway as a transportation roadway (4) when a second coalface (2) is mined, continuing to perform a gob-side entry retaining (12) in a track roadway, cutting and removing a flexible mold bag (13) on the surface of the previous gob-side entry retaining (12) behind the coalface; and when the coal recovery of the second coalface is completed, filling carbon dioxide into the breather pipe (10) in the filling-wall (11) of the first coalface, so that a carbonization reaction occurs on the filling-wall (11), and the filling-wall (11) is broken and decomposed. After the mining of a coal seam is completed, because a top plate is not supported by a coal-rock pillar, the top plate can move and sink fully and the depressurized mining on adjacent coal seams can be achieved, thereby avoiding the stress concentration produced by the hangover of the filling-wall, and facilitating the mining space maintenance, gas extraction and dynamic disaster prevention and control.

Description

technical field [0001] The invention relates to the technical field of pressure-relief mining, in particular to a continuous pressure-relief mining method suitable for close-distance coal seam groups completely without coal pillars in the field of coal mining engineering. Background technique [0002] Coal-measure strata are mainly the occurrence conditions of coal seam groups composed of multiple coal seams. During the mining process of coal seam groups, multiple coal seams interact with each other, which makes the overlying rock movement and mining stress field more complicated. When the superimposed disturbance is coupled with unfavorable factors such as deep high ground stress, high gas, weak rock formation or hard rock formation, catastrophic accidents will often be caused, such as coal and gas outburst, rock burst, gas explosion, etc. Studies have shown that under the condition of short-distance coal seam group occurrence, reasonable planning of coal seam mining seque...

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Problems solved by technology

[0003] However, due to the need to leave a certain width of coal pillars between the working faces, the pressure relief is not sufficient, and the highly concentrated stress on the top and bottom of the coal pillars still brings safety hazards to the adjacent coal seams

In recent years, in order to avoid the adverse effects of such coal pillar stress, the coal mining field is constantly promoting the application of coal pillar-free gobside entry retention technology. This technology achieves the effect of leaving no coal pillars between the working faces, but leaves An artificially filled rock pillar was formed. Although the width of the rock pillar is only a few meters wide, it still forms a large concentrated stress area in the upper and lower adjacent coal seams. When the mining face passes through this area, it still faces the problems of space maintenance and safe mining. major problem

[0004] It can be seen that the technical idea of ​​pressure relief mining for short-distance coal seam groups has been formed, but it is still not possible to fully realize the full pressure relief of adjacent hard-to-mine coal seams by first mining an easy-to-mine coal seam

After the rock pillars with a width of several meters replaced the coal pillars with a width of tens of meters, they are still a safety hazard in the mining of adjacent coal seams

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