Plasma U type method for reducing composite high mine pressure of thick-hard roof and abandoned coal pillars

Abstract

The invention discloses a plasma U type method for reducing composite high mine pressure of a thick-hard roof and abandoned coal pillars. Strong movements between ions are fully utilized for instantly producing high temperature and high pressure characteristics, U type boreholes are drilled in the ground, the number of the U type boreholes is L / d, L is the length of a working face of an underlying coal seam, and d is the borehole space. Each U type borehole is divided into a U type borehole left vertical section, a U type borehole horizontal section and a U type borehole right vertical section, wherein the left and right vertical sections correspondingly penetrate through two residual mining area abandoned coal pillars to reach the thick-hard roof of the underlying coal seam, and the horizontal section is parallel to the advancing direction of the working face in the thick-hard roof of the underlying coal seam. A one-borehole dual-purpose effect and bidirectional operation are achieved, presplitting is conducted on the thick-hard roof of the underlying coal seam and the residual mining area abandoned coal pillars, shock waves are formed, cracks are formed and extend in the thick-hard roof and the residual mining area abandoned coal pillars, the purpose of reduction of the composite high mine pressure of the thick-hard roof and the residual mining area abandoned coal pillars is achieved, thus green mining of a coal mine is achieved, and production is safe.

Description

technical field [0001] The invention relates to a plasma U-type method for reducing composite strong mine pressure of thick and hard roofs and left coal pillars, and belongs to the technical field of coal mining. Background technique [0002] Most of the coal mines in my country use the downward mining method, that is, the overlying coal seam is mined first and then the underlying coal seam is mined. When the underlying coal seam is mined, it will pass through the thick and hard roof between the layers and the remaining coal pillars in the overlying residual mining area, and the coal mining work will be affected by the combined strong mine pressure. [0003] Composite strong rock pressure mainly comes from: (a) thick and hard roof: due to natural geological conditions, the underlying coal seams in many mining areas have thick and hard roofs with large thickness, high strength, no joints and fissures, and good integrity; (b) residual Remaining coal pillars in the mining area:...

AI Technical Summary

Problems solved by technology

However, the technology of reducing composite strong mine pressure by plasma is rarely applied in the field of coal mining technology (especially in the field of "U-type" plasma surface reduction of thick hard roof and residual coal pillars in residual mining area).

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