Method for longwall recovering of room and pillar goaf remaining coal pillars

A technology of legacy coal pillars and room pillars, which is applied in ground mining, mining equipment, earth cube drilling, etc., can solve problems such as hidden dangers in production and life, lack of recovery methods, instability of coal pillars, etc., and achieve simple and mature mining methods, Good safety and convenient material collection

Active Publication Date: 2019-07-19
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, c

Method used

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  • Method for longwall recovering of room and pillar goaf remaining coal pillars
  • Method for longwall recovering of room and pillar goaf remaining coal pillars
  • Method for longwall recovering of room and pillar goaf remaining coal pillars

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 ratio of the coal aggregate filling body used per cubic meter 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 accordi...

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 reducer 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. The particle size of 9mm-13.5mm accounts for 22%, the particle size of 5mm-9mm accounts for 27%, the particle size of 4.3mm-5mm accounts for 17%, the particle size of 0.1mm-4.3mm accounts for 8%. 0.075mm-0.1mm accounted for 4%.

...

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 longwall recovering of room and pillar goaf remaining coal pillars. The method comprises the steps: according to mine conditions and material characteristics, components and proportions of the components of cemented backfill adopting coal as aggregate are designed; a filling station is built, the coal is broken, and the cemented backfill is prepared; backfill slurry is conveyed to a down-hole room and pillar goaf through a pipeline to enable the room and pillar goaf to be full; after the cemented backfill is solidified to the designed strength, a longwall working face is arranged in the room and pillar goaf which is full of the cemented backfill; and stoping equipment is mounted, and the room and pillar remaining coal pillars and the cemented backfill are mined and recovered together. According to the method for longwall recovering of the room and pillar goaf remaining coal pillars, a mining method is simple and mature, safety is good, the yield is high, the cemented backfill adopts the coal as the aggregate, thus the remarkable advantages that the cost is low, material obtaining is convenient, and the coal quality is not influenced after stopingare achieved.

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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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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