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Method for controlling roof caving under condition of hardroof in coal mining

A hard roof and coal mine technology, applied in the field of hard roof control caving, can solve the problems of frequent blasting, large groove depth, analysis and comparison of caving workload, etc.

Inactive Publication Date: 2010-05-12
TAIYUAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main defects of existing methods for dealing with hard roofs are as follows: ① The method of pre-blasting and pre-injecting water in the advanced working face to weaken the hard rock formation is a macroscopic control method. or fracture step, but cannot realize the accurate prediction and control of the time of pressing, the step of pressing and the intensity of pressing, etc., the production management of the working face is always in a passive state, and the safety cannot be guaranteed.
In addition, there are also improper handling that leads to broken roofs and leaks and coal wall slabs, resulting in difficulties in the management of stope roofs and coal walls
②There is no scientific and reasonable calculation method for the step distance and height of the cyclic step top caving. Either the blasting is too frequent, the groove depth is too large, and the amount of roof treatment work is increased, causing serious waste, or the blasting step is too large , the groove depth is too shallow to achieve the effect of putting the top
③ Lack of analysis and comparison of the roof caving workload, it is difficult to achieve the optimal method and the minimum engineering amount. At present, there is an urgent need for a method of quantitatively controlling the hard roof in coal mining

Method used

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  • Method for controlling roof caving under condition of hardroof in coal mining
  • Method for controlling roof caving under condition of hardroof in coal mining
  • Method for controlling roof caving under condition of hardroof in coal mining

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0081] Take Jincheng Qiling Coal Mine as an example. The 15102 working face of this mine is 150m long, the mining height is 2m, and the cycle progress is 0.8m. The coal thickness is 1.8-2.2m, with an average thickness of 2m, including 1-2 layers of gangue. The roof of the coal seam is K 2 Limestone, the average uniaxial compressive strength is 96.77MPa, the tensile strength is 8.59MPa, and the elastic modulus is 35.4GPa. The rock beams on the hard roof are 8.16m thick. The coal seam floor is mudstone or bauxite mudstone.

[0082] The working face adopts four-column support and shielding support, the design rated working resistance of the support is 6075KN / frame, and the design support strength is 900KN / m 2 , the bracket control top distance is 4.5m. Table 1 shows the test results of the mechanical properties of coal and roof rock in the working face.

[0083] Table 1 Mechanical parameters of 15# coal and roof rock

[0084]

[0085] I. Determine the limit span of the ...

Embodiment approach 2

[0108] The initial collapse step of the roof is half of the limit span (that is, the limit span of the roof after treatment is 26m, n=2) according to the method of the middle part of the trough, and the trough with the middle part of the trough can be calculated from the formula (10) The depth and blasting volume are 5.27m; the main technical parameters of the blasting are shown in Table 3.

[0109] Table 3 Main Technical Parameters of Blasting

[0110]

[0111] Others are the same as Embodiment 1.

Embodiment approach 3

[0113] The initial collapse step of the roof is half of the limit span (that is, the limit span of the roof after treatment is 26m, n=2) according to the method of cyclic shallow hole pulling. The groove depth is 5.57m (α=0.4), and the cycle number m>1 of circular shallow hole groove treatment on the roof, the blasting engineering volume is 5.57m. The main technical parameters of the blasting are shown in Table 4.

[0114] Table 4 Main Technical Parameters of Blasting

[0115]

[0116] Others are the same as Embodiment 1.

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Abstract

The invention discloses a method for controlling roof caving under a condition of hardroof in coal mining, belongs to the technical field of coal mining and particularly relates to a quantitative method for controlling roof caving under the condition of hardroof in coal mining. The invention adopts a technical scheme that the method mainly comprises a method for determining a trough pull position, trough pull depth and explosion work amount for initial roof caving under the condition of hardroof and a method for determining the reasonable length of a hanging arch for periodical roof caving under the condition of hardroof. In the invention, the roof caving mode is controlled to reduce the pace of initial top coal collapsing of a working face, the through pull depth and the explosion work amount are the smallest in all hardroof control modes and the operation is easy; the relationship between the pace of initial top coal collapsing and the trough pull depth is specified quantitatively; based on the design working resistance of a bracket of the working face, the method for determining the reasonable length of the hanging arch of a hardroof rock beam is obtained, so the hardroof control is more scientific, quantitative, accurate and simple; and the method can be widely used in control of roof caving under the condition of hardroof in various kinds of coal mining.

Description

technical field [0001] The invention relates to a method for controlling caving of a hard roof in coal mine mining, which belongs to the technical field of coal mining, and specifically relates to the determination and hardness of the initial caving groove position, groove depth, and blasting engineering quantity of a hard roof in coal mining. The technical scheme of the method for determining the reasonable suspended roof length of the roof periodically caving. Background technique [0002] Occur directly on the coal seam or directly on the thinner roof with high strength, large thickness, strong integrity, and undeveloped joints and fissures. After the coal seam is mined, it can be exposed in a large area in the goaf. The roof that is not easy to sag naturally is a hard roof. The hard roof of the longwall working face has a large initial pressing step distance, which can reach about 140m; the period suspended roof is long, which can reach about 60m; once the hard roof wit...

Claims

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Application Information

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IPC IPC(8): E21C41/16
Inventor 王开康天合王东
Owner TAIYUAN UNIV OF TECH
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