A method for fully mechanized caving and re-mining of residual bottom coal

Abstract

The invention relates to a method for re-mining residual floor coal in a fully-mechanized top coal caving face. The method is used for re-mining residual floor coal with complete coal seam at the bottom and fragmentized coal bodies at the upper part and having accumulated water, CO, CO2, gas and other harmful gases in the fragmentized coal bodies and an upper goaf; the method comprises the steps of proving reserves, accumulated water amount and accumulated gas amount, draining, filling nitrogen gas and fire retardants, tunneling an upper gateway and a lower gateway of a re-mining working face in a width equivalent to a distance away width of one-two roadways from re-mining residual floor coal bottom plate, reasonably setting zone protective coal pillars, cutting holes, reinforcing a top plate and controlling the coal seam, and then performing re-mining the residual floor coal in the fully-mechanized top coal caving face, wherein the ratio of the thickness of the cut coal and the sum of the thicknesses of the controlled coal seam and the fragmentized coal body at the upper part is controlled to be 1:3. The method for re-mining the residual floor coal liberates dead reserves, fully excavates and unleashes resources potential, improves the economic benefit, relieves the enterprise pressure and prolongs the life of mines.

Description

technical field [0001] The invention relates to a method for re-mining residual bottom coal, in particular to a method for fully mechanized top-coal caving mining of residual bottom coal. technical background [0002] Due to the limitation of mining technology level, equipment conditions, capital and other factors, there is a large amount of layered mining of residual bottom coal. In addition, many coal mines adopt the method of "mining top coal and discarding bottom coal" in mining operations to ensure safe production. These methods The bottom coal with considerable reserves remains, which reduces the resource recovery rate and shortens the service life of the mine. [0003] Existing available resources are depleting day by day, energy supply and demand are becoming more and more tense, coal is a valuable non-renewable resource, if the residual bottom coal is not extracted using the existing roadway layout system, it will cost a lot of money to carry out secondary mining in...

AI Technical Summary

Problems solved by technology

During the primary mining process, the roof collapses, and the fissures may communicate with the aquifer in the overlying strata, causing the roof water to enter the goaf, causing secondary mining to be threatened by goaf water; in addition, if the goaf is completely When there is no water accumulation, the coal seam may be oxidized or spontaneously ignited. In the case of insufficient air, the oxidation of the coal seam will naturally produce a large amount of CO, which seriously threatens the safety of recovery. When both are combined, two threats may exist at the same time. Added technical difficulties to re-mining the residual bottom coal

[0006] (2) Risk of roof fall of residual bottom coal

During a mining process, the support pressure of the working face caused damage to the residual bottom coal, and the integrity of the bottom coal was damaged to a certain extent, which caused great difficulties for the roadway of the lower coal seam and the support of the working face

On the other hand, during the mining of the working face, neither laying the net nor injecting yellow mud into the goaf to form an artificial false roof resulted in disordered, loose and broken rock accumulation in the goaf formed by the primary mining. No cohesion and poor cementation make the maintenance of the roof even more difficult. In the process of re-mining the residual bottom coal, these conditions can easily induce roof fall accidents, affect the safety of the residual coal re-mining, and increase technical difficulties for the re-mining of the residual bottom coal

[0007] (3) Residual coal recovery efficiency is low

The mining of the residual bottom coal is threatened by various threats, which increases the technical difficulty of the roadway layout and coal mining process of multiple mining; at the same time, in order to ensure safe mining, production efficiency is often sacrificed, resulting in low mining efficiency

[0008] (4) High input cost

Aiming at the occurrence and destruction characteristics of this type of residual coal, the prior art that can be obtained is: "a kind of method for re-mining and recovering coal in underground coal mines" of CN101025085 and the "a kind of warehouse mining method" of CN101302931. The method of re-mining after coal and corner coal recovery” provides a method of recovering coal pillars and corner coal by using the original development system. These two invention patents are used to set Roadways and short-walled working faces not only increase the number of equipment relocations, but the overall recovery efficiency is low; another example is the publication number: CN102425453A "A Large-scale Recovery Method for Filling the Damaged Area of ​​a Small Kiln" provides a method for using grouting The method of filling the damaged area and then arranging the working face for mining. In this method, the small kiln damaged area can be mined by filling the goaf with grouting, but the mined coal contains a large amount of grouting filling materials, which increases the transportation cost and reduces the coal quality. , also increases the difficulty and cost for the later stage coal washing; there is also the invention patent of "a method for filling and re-mining the strip goaf" with the publication number of CN103104287A, which discloses a method for filling the strip goaf, Reusing the method of mining striped coal pillars with the original development system, this method has produced a large number of striped coal pillars, but the application object is limited to the special case of re-mining the striped coal pillars

[0010] The above-mentioned existing re-mining methods are coal pillars or corner coals that are divided into small pieces. These residual coal resources cannot be re-mined by conventional mining methods due to problems such as resource distribution, size, and technical difficulty.

For the re-mining of the residual bottom coal, because of the above-mentioned many technical difficulties, in the existing published literature, there is no report on the relevant re-mining method.

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