Mining stopping method for downwards mined underlying seams of coal seam group

Abstract

The invention discloses a mining stopping method for downwards mined underlying seams of a coal seam group. When working surface coal walls are distant from a mining stopping line for 30 m, the working surfaces begin to be adjusted; the mining is implemented along top plates and bottom plates of coal seams; the working surfaces are aligned and leveled, so that the gradients thereof are the same and the mining height is controlled in a range of 2.4 to 2.5 m; two-layer rhombic metal nets are laid within the scope of 11 m from the working surfaces to the mining stopping line, so that the condition that the top plates of the downwards mined underlying seams of the coal seam group are difficult to be supported and protected due to break is effectively controlled. After the mining is stopped for the working surfaces, top plates on a bracket main beam are supported and protected by using two rows of joist steels in a step manner, and two wood point poles with phi not less than 0.18 m are supported under a bracket top beam and leant against a base box; and machine way top plates are supported and protected by using two rows of anchor ropes, three rows of anchor bolts, slanted beams and hydraulic monomers, so that the condition that the downwards mined underlying seams of the coal seam group are easy to leave seams on the top plates under the influence of overlying seam supporting pressure, coal-rock mass internal stress and advanced stress.

Description

technical field [0001] The invention relates to the technical field of coal mining, in particular to a mining stop method for descending mining of lower coal seams of coal seam groups. Background technique [0002] When mining near-horizontal and gently inclined coal seam groups, the descending mining sequence is usually adopted, because the descending mining is simple and has little impact on the underlying coal, which is beneficial to the mining of the underlying coal and roadway maintenance. However, when the distance between coal seams is small, the bearing pressure formed after the mining of the upper coal seam may be transmitted to the lower coal seam. At the same time, as the mining depth increases, the absolute value of the stress in the coal rock body will increase, and the frequency and intensity of rock burst will also increase. bigger. Therefore, the support pressure formed after the mining of the upper seam and the stress generated by the increase of the mining...

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Problems solved by technology

[0003] The purpose of the present invention is to solve the defects of easy detachment layer of the roof and poor support quality in the current downward mining of the lower coal seam technology, and to provide a method for stopping mining of the lower coal seam in the downward mining of the coal seam group

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