Method for controlling surface collapse in coal mining process

Abstract

The invention relates to the field of 'three-under' coal compressing mining, and provides a method for controlling surface collapse in the coal mining process. The method comprises the following stepsthat sampling holes are formed in the surface; all rock stratums are sampled through the sampling holes so as to obtain layer position information of a main key stratum and all interior key strata; according to the layer position information of the main key stratum and all the interior key strata, a plurality of slurry-injecting holes extending to the grouting layer position correspondingly are formed in the surface in the advance direction of a working face; the grouting layer position is the contact face of the main key stratum and a weak layer on the lower portion of the main key stratum;water is injected into the slurry-injecting holes through a high-pressure pump; and coal mining is conducted in the advance direction of the working face, meanwhile, whether the water pressure in allthe slurry-injecting holes is decreased or not is judged, and if yes, pre-mixed coal ash slurry is injected into the corresponding slurry-injecting holes through the high-pressure pump. According to the method, the grouting time is judged through the change of the water pressure in the pre-formed slurry-injecting holes, the situation that the main key stratum is broken off in the coal mining process is avoided, and maximum surface subsidence reducing in the sense of space conservation is achieved.

Description

technical field [0001] The invention relates to the field of "three-down" coal pressing mining, in particular to a method for controlling ground surface subsidence during coal mining. Background technique [0002] At present, coal mining under buildings in my country mainly includes strip mining method, goaf filling method and traditional overlying rock separation layer grouting filling method. Among them, the strip mining method has played an extremely important role in liberating my country's "three under" coal pressing, but due to its low recovery rate, low production efficiency, and high tunneling rate, it has gradually become obsolete. The goaf filling method needs to arrange the coal mining system and the filling system at the same time in the underground. Because of the serious interference between coal mining and filling, the coal mining efficiency is greatly affected. In addition, its filling cost is high, which is difficult for coal mining enterprises to bear. Ho...

AI Technical Summary

Problems solved by technology

Among them, the strip mining method once played an extremely important role in liberating my country's "three under" coal pressing, but due to its low recovery rate, low production efficiency, and high tunneling rate, it has gradually become obsolete.

The goaf filling method needs to arrange the coal mining system and the filling system at the same time in the underground. Due to the serious interference between coal mining and filling, the coal mining efficiency is greatly affected.

In addition, its filling cost is high, which is unbearable for coal mine enterprises

However, the traditional overlying rock detachment layer grouting filling method is that after the detachment layer is formed, there is a certain deformation on the surface, which cannot effectively control the surface subsidence.

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