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Coal-pillar-free mining method for pre-cracking arching under hard roof condition

A technology of hard roof and mining method, used in underground mining, surface mining, underground chambers, etc., can solve the problems of easy air leakage and broken roadway roof, and achieve the effect of reducing risk, reducing roadway deformation and easy construction.

Active Publication Date: 2019-05-31
SHANDONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to solve the technical problem that the roadway roof is broken and easy to leak air when mining without coal pillars under the condition of hard roof, the present invention provides a coal pillar-free mining method of pre-split arching under the condition of hard roof. The specific technical scheme is as follows

Method used

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  • Coal-pillar-free mining method for pre-cracking arching under hard roof condition
  • Coal-pillar-free mining method for pre-cracking arching under hard roof condition
  • Coal-pillar-free mining method for pre-cracking arching under hard roof condition

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Embodiment 1

[0033] In order to adapt to the coal pillarless mining under the hard roof condition, a coal pillarless mining method of pre-splitting and arching under the hard roof condition is proposed. After the working face is advanced, the upper part of the direct roof is cracked. Due to the connection of the lower part, the direct roof bends and sinks into an arch. The roadway is deformed, and due to the small blasting range of the pre-splitting holes, a relatively complete roof is maintained, which can effectively prevent air leakage from the roof. The specific construction steps of the method include:

[0034] Step A. Excavate the recovery roadway at the first mining face, and use bolts and anchor cables to support the recovery roadway.

[0035] The roof of the mining roadway in the first mining face is supported by anchor cables + steel belts + anchor nets. The steel belt can be M steel belt, and the number of anchor cables is set according to the formula Calculate, where n is th...

Embodiment 2

[0051] On the basis of Example 1, taking the mining of the 16# coal seam in a certain mine as an example, the coal pillar-free mining method of pre-splitting and arching under the condition of a hard roof is further described in detail.

[0052] The 16# coal seam of a certain mine is relatively stable, with a strike length of 741.1m, located in the lower part of the Taiyuan Formation, under ten lower limestones, with an average thickness of 0.86m; the columnar diagram of the coal seam is as follows Figure 5 shown. The strike of the coal strata is 30°-40° northwest, and the inclination is generally around 3°-8°; the relative emission of mine gas is 0.79m 3 / t, for low gas mine; CO 2 The relative gushing volume is 1.38m 3 / t; the coal dust explosion index is 44.54%, which has the danger of coal dust explosion; the shortest spontaneous combustion period of coal is 94 days; the spontaneous combustion tendency of coal seam is class II spontaneous combustion coal seam. The direc...

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Abstract

The invention provides a coal-pillar-free mining method for pre-cracking arching under a hard roof condition, and relates to the technical field of underground mining methods. The method comprises thesteps that A, a mining roadway of a first mining working face is excavated, and anchor rods and anchor cables are used for supporting the mining roadway; B, pre-cracking holes are formed in a roof inthe mining roadway along the coal wall of the working face, wherein the pre-cracking holes are perpendicular to the roof, and the length of the pre-cracking holes is equal to the thickness of the immediate roof; C, hydraulic supports are arranged at one side of the coal wall of the first mining working face; D, the pre-cracking holes within the range of 50-70 m on an advanced working face are loaded with explosive for blasting to crack the immediate roof; E, push mining is conducted on the working face, and the immediate roof of a pre-cracking section at the rear portion of the working face is subjected to sinking arching; F, after the sinking amount of the roof is stabilized, the height of the roadway is adjusted; G, a mining roadway of an adjacent working face is excavated, steps A to Fare repeated, and the hydraulic supports in the mining roadway of the last working face are recovered along with pushing of the adjacent working face. The method solves the problem that roofs are broken and easily leak wind, and has the advantages that the deformation amount of the roadways is small, and construction is convenient.

Description

technical field [0001] The invention relates to the technical field of underground mining methods, in particular to a method for coal pillar-free mining by pre-splitting and directly arching beside a roadway under the condition of a hard roof. Background technique [0002] At present, in the process of coal mining, due to the large step distance of the roof collapse of the hard roof, the goaf is exposed to a large range, and the pressure transmitted to the coal walls on both sides of the roadway is also relatively large, which may lead to rock burst or large-scale Accidents such as roof fall affect the safe production of coal mines. Pillarless mining method is a mining technology that maintains the roadway without leaving coal pillars in the process of coal mining, and it is necessary to control the hard roof to carry out coal pillarless mining under the condition of hard roof. Different scholars hold different opinions on roadway roof control under hard roof conditions: ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21C41/18E21D20/00E21D11/15F42D3/00
Inventor 石永奎郝建朱怀志王新董洪清林嘉辉李惠通
Owner SHANDONG UNIV OF SCI & TECH
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