Method for extracting gas from separation layer below overlying strata, draining water and grouting through combined drill hole

Abstract

The invention discloses a method for extracting gas from a separation layer below an overlying strata, draining water and grouting through a combined drill hole and belongs to a mine disaster prevention method. The method for extracting gas from the separation layer below the overlying strata, draining water and grouting through the combined drill hole includes that installing a drill site at a transportation roadway of a preparatory work face adjacent to a coalface, constructing the combined drill hole in the part about to generate the separation layer below the overlying strata above the gob of the coalface in a mode of keeping away from a caving zone, wherein the combined drill hole is composed of an inside gas extraction pipe and a water draining-grouting pipe; after the separation layer is generated, preventing the mine disaster according to the stages that firstly, draining water from the separation layer through the combined drill hole; secondly, after the gas is gathered in the separation layer after the water in the separation layer is emptied, using the primary combined drill hole to extract the gas from the separation layer; finally, after the water and gas are completely drained and extracted from the separation layer, filling cement paste to the separation layer through the primary combined drill hole. The method for extracting gas from the separation layer below the overlying strata, draining water and grouting through the combined drill hole is capable of solving the mine disasters of water bursting in mine, gas outburst (gas emission), rock burst, surface subsidence and the like through the combined drill hole, the separation layer water and gas extraction rate is high, and the grouting effect is good.

Description

technical field [0001] The invention relates to a method for preventing and controlling coal mine disasters, in particular to a method for extracting gas from a separation layer under overlying rock and draining grouting by using composite drilling. Background technique [0002] When the coal seam is covered by a thick and hard rock layer, due to the obvious differences between the coal measure strata and the overlying rock in terms of geological structure, strength, and deformation properties, in coal seam mining, there will be obvious separation layers under the thick and hard overlying rock above the goaf of the mining face , and is easily filled by groundwater and gas to form a closed layered water body, layered gas or a layered water-gas mixture. At the same time, with the increase of the mining area, the thick and hard overlying rock will be unstable and broken, often forming rock burst and causing surface subsidence. At the same time, the shock wave formed by the bre...

AI Technical Summary

Problems solved by technology

At present, some mines use a single borehole to extract layer gas, drainage or grouting. The utilization rate of the borehole is not high, resulting in waste of the project; The roadways on both sides of the face are constructed in the separation layer space under the overlying rock above the goaf, so the drilling must inevitably pass through the caving zone above the goaf, the drilling is easy to collapse, and it is difficult to maintain. And the cost is high

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