A method for liquid nitrogen low-temperature pre-cracking coal mine thick, hard and difficult-to-break roof

A liquid nitrogen, low temperature technology, applied in ground mining, earthwork drilling, underground mining, etc., to reduce the overhang area, good effect, and avoid dynamic disasters
CN104763426BActive Publication Date: 2017-01-25TAIYUAN UNIV OF TECH
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Patent Information

Authority / Receiving Office
CN Β· China
Patent Type
Patents(China)
Current Assignee / Owner
TAIYUAN UNIV OF TECH
Publication Date
2017-01-25

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Abstract

The invention discloses a method for low temperature precracking of a thick hard difficult-to-break coal mine top board by liquid nitrogen, and belongs to the technical field of coal mine safe mining. According to the method, the characteristics of induction of the liquid nitrogen on micro-fissure of rock / pore expanding under low temperature condition are fully used for realization of advance precracking of the thick hard difficult-to-break coal mine top board, area of suspension roof of the thick hard difficult-to-break coal mine top board can be reduced, first / periodic weighting step and ground pressure strength can be reduced, dynamic disaster caused by thick hard top board instantaneous caving during full-mechanized caving mining can be effectively avoided, and safety in production can be ensured.
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Description

technical field

[0001] The invention belongs to the technical field of coal mining, and in particular relates to a method for liquid nitrogen low-temperature pre-cracking of a hard and refractory roof in coal mines. Background technique

[0002] Coal mine hard roofs with large thickness, high strength, compact structure and good integrity exist widely in many mining areas in my country. When fully mechanized caving mining of thick and extra-thick coal seams, the thick and hard roof of the stope cannot collapse in time. With the gradual advancement of the working face, the suspended area of ​​the thick, hard and difficult roof of the stope will gradually increase, which will inevitably increase the difficulty of supporting the working face of the stope; at the same time, the initial / period The pressure step is very large, and it will accumulate a large amount of energy with the gradual advancement of the working face. When the self-weight of the thick and hard roof of the st...

Claims

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