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A long-wall method for recovering coal pillars left in room-and-pillar goaf

A technology of legacy coal pillars and room-and-pillars, applied in ground mining, mining equipment, earthwork drilling and mining, etc., can solve problems such as inability to solve ventilation problems, natural fire hazards in goafs, and lack of recovery methods

Active Publication Date: 2021-07-27
TIANDI SCI & TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The coal recovery rate of the room-and-pillar mining method is only 30%-50%, and the recovery rate of small coal mines in some places is even less than 30%. A large number of high-quality legacy coal pillar resources are left underground, resulting in the waste of a large amount of coal resources
2) The risk of large-scale collapse of the roof
With the passage of time, the rheology of the coal pillar will cause a large area of ​​the roof to collapse suddenly, causing a subsidence earthquake, and bringing safety hazards to the production and life of the mine and the mine
3) Hidden danger of natural fire in goaf
4) Destroy groundwater and cause soil erosion
The coal pillar recovery technology used in the past has problems such as inability to solve the ventilation problem, difficult roof management, sudden instability of the remaining coal pillar, and low recovery efficiency, lacking a safe and efficient recovery method

Method used

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  • A long-wall method for recovering coal pillars left in room-and-pillar goaf
  • A long-wall method for recovering coal pillars left in room-and-pillar goaf
  • A long-wall method for recovering coal pillars left in room-and-pillar goaf

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] A mine has a room-and-pillar goaf, a near-horizontal coal seam, buried depth H = 410m, mining thickness M = 3m, mining width L = 6m, and leftover coal pillar width D = 6m. The proportion per cubic meter of the coal aggregate filling body used is: coal 1394Kg; fly ash 66Kg; cementing material 40Kg; admixture accelerator 5.5Kg and water reducer 2.5Kg; mine water 590Kg. The slurry mass concentration is 71.9%, the slump is 23cm, and the 28d uniaxial compressive strength is 1.1MPa.

[0037] The coal is coal lumps and coal particles with a particle size of less than 24mm after secondary crushing. 12% for 13.5mm-17.5mm, 23% for 9mm-13.5mm, 29% for 5mm-9mm, 16% for 4.3mm-5mm, 0.1 mm-4.3mm accounted for 8%, particle size of 0.075mm-0.1mm accounted for 3%.

[0038] The fly ash is the secondary fly ash of the power plant, the cementing material is ordinary portland cement of grade 32.5, and the quick-setting agent is composed of alumina clinker, sodium carbonate and quicklime ac...

Embodiment 2

[0046] In the room-and-pillar goaf of a mine, the inclination angle of the coal seam is α=5°, the buried depth is H=570m, the mining thickness is M=4.5m, the mining width is L=5m, and the width of the remaining coal pillar is D=8m. The proportion of the coal aggregate filling body used is: coal 1450Kg; fly ash 66Kg; cementing material 42Kg; admixture accelerator 6.1Kg and water reducing agent 1.9Kg; mine water 574Kg. The slurry mass concentration is 72.4%, the slump is 23.5cm, and the 28d uniaxial compressive strength is 1.5MPa.

[0047] The coal is coal lumps and coal particles with a particle size of less than 20mm after secondary crushing, the coal type is anthracite, 7% of the particle size is 17.5mm-20mm, and 15% of the particle size is 13.5mm-17.5mm. 22% of the particle size is 9mm-13.5mm, 27% of the particle size is 5mm-9mm, 17% of the particle size is 4.3mm-5mm, and 8% of the particle size is 0.1mm-4.3mm. 0.075mm-0.1mm accounted for 4%.

[0048] The fly ash is the th...

Embodiment 3

[0056] In the room-and-pillar goaf of a mine, the coal seam dip angle is α=7°, the buried depth is H=634m, the mining thickness is M=5.8m, the mining width is L=4m, and the remaining coal pillar width is D=9m. The proportion of the coal aggregate filling body used is: coal 1503Kg; fly ash 70Kg; cementing material 35Kg; admixture accelerator 5.2Kg and water reducer 2.8Kg; mine water 612Kg. The slurry mass concentration is 72.5%, the slump is 22.5cm, and the 28d uniaxial compressive strength is 1.7MPa.

[0057] The coal is coal lumps and coal particles with a particle size of less than 22mm after secondary crushing. 11% with a diameter of 13.5mm-17.5mm, 24% with a particle size of 9mm-13.5mm, 31% with a particle size of 5mm-9mm, 11% with a particle size of 4.3mm-5mm, and 11% with a particle size of 0.1mm-4.3mm accounted for 8%, particle size 0.075mm-0.1mm accounted for 6%.

[0058] The fly ash is the third-grade fly ash of the power plant, the cementing material is carbide sla...

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Abstract

The invention provides a method for recovering coal pillars left over from a room-and-pillar goaf with long walls. station to complete the crushing of coal and the preparation of the cemented filling body; transport the filling body slurry through pipelines to the underground room-and-pillar goaf to fill the room-pillar goaf; The longwall working face is arranged in the room-and-pillar type goaf of the filling body; mining equipment is installed to mine and recover the leftover coal pillars of the room-and-pillar type and the cemented filling body together. The method provided by the invention provides a method for recovering coal pillars left in a room-and-pillar type goaf with a simple and mature mining method, good safety, and high yield; the cemented filling body uses coal as aggregate, and has the advantages of low cost, convenient material acquisition, The obvious advantage of not affecting the coal quality after mining.

Description

technical field [0001] The invention relates to the technical field of recovery of coal pillars left in room-and-pillar mining and mine filling mining, in particular to a method for recovering coal pillars left in a room-and-pillar goaf with a long wall. Background technique [0002] In recent years, with the depletion of coal resources in the eastern region, the Shanxi, Shaanxi and Inner Mongolia regions have gradually become my country's important raw coal production and coal export regions. However, after years of mining in this area, a large number of room-and-pillar goafs have been left, and the room-and-pillar goafs have brought the following problems to the local area: 1) Waste of a large amount of high-quality coal resources. The coal recovery rate of the room-and-pillar mining method is only 30%-50%, and the recovery rate of small coal mines in some places is even less than 30%. A large number of high-quality legacy coal pillar resources are left underground, causin...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21F15/00E21D15/60E21C41/18
CPCE21C41/18E21D15/60E21F15/005
Inventor 徐刚刘鹏亮祝凌甫张震崔锋黄志增王浩宇
Owner TIANDI SCI & TECH CO LTD
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