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Method for low temperature precracking of thick hard difficult-to-break coal mine top board by liquid nitrogen

A liquid nitrogen, low temperature technology, used in ground mining, earthwork drilling, underground mining, etc., to achieve the effect of wide source, reducing pressure step distance and reducing the area of ​​suspended roof

Active Publication Date: 2015-07-08
TAIYUAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are few reports on the application of liquid nitrogen low-temperature pre-cracking technology in the field of coal mining technology (especially in the aspect of advanced pre-cracking of thick, hard and difficult-to-break roofs in coal mines)

Method used

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  • Method for low temperature precracking of thick hard difficult-to-break coal mine top board by liquid nitrogen
  • Method for low temperature precracking of thick hard difficult-to-break coal mine top board by liquid nitrogen
  • Method for low temperature precracking of thick hard difficult-to-break coal mine top board by liquid nitrogen

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Embodiment Construction

[0037] In order to have a clearer understanding of the technical objectives, features and effects of the present invention, the supercritical CO 2 The thick, hard and difficult-to-break roof of a Carboniferous coal seam in a mine of the Pre-Splitting Tongmei Group will be further explained in detail.

[0038] The buried depth of the Carboniferous coal seam in a certain mine of Tongmei Group is 400-600m, and the No. 3-5 coal seam mainly mined is an extra-thick coal seam with a thickness of 14-20m. The carbonaceous coal seam roof of this ore is hard and complete, mainly composed of silt-fine sandstone and medium-coarse sandstone. When the Carboniferous coal seam is mined, the overlying thick and hard roof has a large suspended area and cannot collapse in time, which makes it more difficult to support the working face of the stope; If the gap is very large, it will accumulate a large amount of energy with the gradual advancement of the working face, and cause an instant overall ...

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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.

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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Application Information

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IPC IPC(8): E21C41/18E21B43/26
CPCE21B43/26E21C41/18
Inventor 冯国瑞白锦文郭育霞张玉江戚庭野郭军李振康立勋
Owner TAIYUAN UNIV OF TECH
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