Method for determining instable critical thickness of horizontal ore pillar in multi-level simultaneous mining mode

A technology of critical thickness and determination method, which is applied in ground mining, mining equipment, underground mining, etc., can solve problems such as distortion of research results, and achieve the effects of simple determination method, reduced waste of resources, and safe recycling

Inactive Publication Date: 2018-04-17
YILIANG CHIHONG MINING IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, when the size of the horizontal pillar does not satisfy the sheet structure, the research results are distorted

Method used

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  • Method for determining instable critical thickness of horizontal ore pillar in multi-level simultaneous mining mode
  • Method for determining instable critical thickness of horizontal ore pillar in multi-level simultaneous mining mode
  • Method for determining instable critical thickness of horizontal ore pillar in multi-level simultaneous mining mode

Examples

Experimental program
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Effect test

experiment example 1

[0032] 1. Numerical simulation of downward horizontal layered rectangular approach cemented filling mining method

[0033] (1) Geometric model establishment

[0034] Modeling area selection: FLAC 3D software was used for numerical analysis and research. According to the research problem and the mining status of a lead-zinc mine, the ore body from the depth of 680m to 760m below the surface was selected as the research and analysis object, and the ore body dip angle was 72° , take 40m upward along the ore body strike, and 50m perpendicular to the ore body strike direction to establish a model. The upper part of the ore body and the surrounding rocks are taken as 3 times the size of the ore body, and the surrounding rocks at the bottom are taken as 100m. The numerical model is a cuboid (350m×280m×420m), enclosing the ore body in the middle.

[0035] Model boundary and failure criterion: Displacement constraints (Fix) are used around the model and at the bottom, free bounda...

Embodiment 1

[0055] A lead-zinc mine adopts the panel mechanized downward layered approach type cemented paste filling mining method, and the upper and lower layers are vertically staggered. With the simultaneous mining of multiple middle sections, the unmined ore body in the middle section of 760 underwent large deformation under the condition of weak bottom support and high stress, and the ore showed fragmentation; the ore pillar had obvious tension cracks and new cracks , the closed joints expand, and there are obvious dislocations; at the same time, the filling body does not connect to the bottom. Based on the above phenomena, it can be seen that the horizontal ore pillar in the middle section of 760 was formed and gradually destroyed. At this time, the vertical thickness of the horizontal ore pillar is 22m.

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Abstract

The invention discloses a method for determining an instable critical thickness of a horizontal ore pillar in a multi-level simultaneous mining mode. The method comprises the following steps: a physical mechanics determination step of ore rock mass, namely intercepting one part of pillar body of a to-be-mined horizontal ore pillar as a sample, and determining volume density rho, a Poisson's ratiou, an ultimate tensile strength sigmaT of the sample; a horizontal ore pillar measurement step, namely measuring a length a of an extended ore body direction and a length b of a vertical ore body direction of the to-be-mined horizontal ore pillar, and preliminarily determining a minimal retained vertical thickness h of the horizontal ore pillar during mining; a maximum tension stress calculation step, namely calculating maximum tension stress sigma(tmax) stressed by the horizontal ore pillar; and an instable critical thickness determination step, namely taking the minimal retained vertical thickness h of the horizontal ore pillar as the instable critical thickness when sigma(tmax) is equal to [sigma(T)]. According to the method disclosed by the invention, a determination mechanics model ofthe critical thickness of the horizontal ore pillar is established based on a Vlasov thick-plate theory, a theoretical basis is provided for accurately determining the critical thickness of the horizontal ore pillar in time for the mine, safety recovery of the horizontal ore pillar is improved, and the utilization rate of ore resources is increased.

Description

technical field [0001] The invention belongs to the technical field of mineral excavation, and in particular relates to a method for judging the critical thickness of the instability critical thickness in a multi-middle section simultaneous mining mode with simple method for judging the critical thickness of the horizontal ore pillar, safe recovery of the horizontal ore pillar, and high recovery rate. Background technique [0002] In recent years, the horizontal layered filling mining method (upward / downward) mostly adopts excavation along the full horizontal section of the ore body, and the mode of mechanized large panel, continuous arrangement without ore pillars, and simultaneous recovery of double or even multiple middle sections has been widely used. When double middle sections or multiple middle sections are mined at the same time and the approach filling cannot be connected to the top, horizontal ore pillars will inevitably be dynamically formed. The horizontal pillar...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21C41/22E21F15/00
CPCE21C41/22E21F15/00
Inventor 乔登攀罗进玉拾昭周高明黄昌兴唐琳崔数文石宏伟杨锦欣罗俊
Owner YILIANG CHIHONG MINING IND
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