Method for determining chamber blasting optimum thickness of wide span dead zone top plate and blasting method thereof
A definite method and large-span technology, applied in blasting and other directions, can solve problems such as difficulty in determining the height of centralized chemical chambers, long construction period, and potential safety hazards, and achieve the effects of small consumption of explosives per unit, short construction period, and convenient management
Inactive Publication Date: 2009-04-22
CINF ENG CO LTD
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Problems solved by technology
[0007] The above three methods of filling gobs have a common disadvantage: long construction period (generally more than half a year), complicated management, large investment, and high filling cost
Moreover, the first two filling methods will also have a certain impact on mine environmental protection. The third method arranges a centralized chemical chamber in the rock mass around the goaf, or conducts deep hole blasting, which will affect the stability of the rock mass around the goaf. At the same time, it is difficult to determine the height of the centralized chemical chamber, because it must not only meet the requirements for the thickness of the cushion layer for ground mining operation safety, but also meet the safety thickness requirements for construction safety.
If the setting height is not well selected, it will not guarantee the safety of the operation, but also may increase the amount of blasting work, prolong the construction period, and increase the investment.
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[0041] like Figure 1-Figure 3 As shown, in the first preferred embodiment, the goaf roof caving layer area F 0 13000m 2 , the height H from the buffer layer to the roof is 40m, the thickness L of the roof caving layer is 20m, and the exposed area F of the roof is 14800m 2 , rock roughness coefficient k of the buffer layer c =6.6×0.1da, da is 0.5, da is a coefficient related to rock hardness and roughness, and the range of da is 0.4-0.6. First, the finite element method is used to simulate the stress distribution of the four sections of the goaf under the action of the rock mass stress field, and the point stress safety factors on the sections are all greater than 1.0, which proves that the goaf roof rock as a whole is stable ; Then calculate the buffer cushion thickness h that satisfies the safety production of ground mining in the goaf b =0.74k c h 1.25 L 0.02 (F 0 / F)=19.3m (this formula is the thickness formula of the buffer layer proposed by B.P Imenitov); and the...
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The invention discloses a method for determining optimal thickness of a large-span dead zone crest slab for chamber blasting and a method for blasting the chamber; the method is only applied to the condition that a goaf crest slab rock mass is in stable sate. The method includes the following steps: firstly, the thickness of a buffer cushion which satisfies safe production in goaf area is calculated, safe allowable distance of blasting vibration is calculated; then, safe thickness for large scale blast working construction is calculated; finally, according to the requirement that the safe thickness of the large scale blast construction is greater or equal to the thickness of the buffer cushion for safe production, the optimal thickness of the dead zone crest slab for chamber blasting is determined, laneway is excavated, explosive is placed, and strip chamber blasting is implemented. The optimal thickness of the large-span dead zone crest slab for chamber blasting provided by the invention not only ensures the safe operation, but also reduces the blast quantities, shortens the construction period and reduces the investment as much as possible.
Description
Technical field: [0001] The invention relates to a blasting method in mining, in particular to a method for determining the optimal thickness of a roof chamber blasting in a large-span void area and a blasting method thereof. Background technique: [0002] In the process of mining underground mines, the goaf method is generally used for mining, and the span of the goaf is generally 20M-50M. When the span of the goaf is greater than 50M, it is a large-span goaf. [0003] In order to protect the safety of underground mining operations, a cushion layer of a certain thickness must be formed on the roof of the ore body below the goaf. In the past production practice, the following methods are usually used to fill the goaf to form a cushion layer: [0004] 1. Tailings filling method, that is, a sand pumping station is established in the tailings pond, and the tailings are transported to the goaf through pipelines to form a cushion layer with a thickness required by the design. ...
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IPC IPC(8): F42D3/00
Inventor 李悦良
Owner CINF ENG CO LTD