Method for preventing spontaneous combustion of coal in upper and lower levels of goafs in contiguous coal seam groups

Abstract

The invention relates to the field of coal mine fire prevention, in particular to a method for preventing spontaneous combustion of coal in upper and lower levels of goafs in contiguous coal seam groups in lower layer of coal seam of low seam thickness and small coal seam spacing, in the mining and recovery process. The method for preventing spontaneous combustion of coal in the upper and lower levels of goafs in the contiguous coal seam groups includes the following steps: determining coal spontaneous combustion prevention and control key areas in the upper and lower goafs of the contiguous coal seam groups; carrying out surface drilling and grouting processes in the coal spontaneous combustion prevention and control key areas before mining the lower layer coal seam in the contiguous coalseam groups so as to completely cover the coal left in the upper goafs; after 500m below the lower layer of the contiguous coal seam groups is mined, and 15 days after the completion of mining, connection roadway closed grouting hole grouting and return airway embedded grouting pipe grouting are carried out in the coal spontaneous combustion prevention and control key areas in the upper and lowergoafs of the contiguous coal seam groups.

Description

technical field [0001] The invention relates to the field of fire prevention and control in coal mines, in particular to a method for preventing spontaneous combustion of coal in upper and lower mined-out areas of short-distance coal seam groups during mining and recovery of coal seam groups with shallow coal seam burial and close coal seam spacing. Background technique [0002] In recent years, the country's coal industry has vigorously promoted the construction of large-scale coal bases in the west in accordance with the development idea of ​​"controlling the east, stabilizing the middle, and vigorously developing the west", focusing on the construction of a number of modern mines with a level of 10 million tons. The western region is rich in coal resources, the coal seam is prone to spontaneous combustion, the buried depth is generally not more than 300m, the inclination angle of the coal seam is small (generally 0-3 degrees), and it is mined in a group at a short distance...

AI Technical Summary

Problems solved by technology

Using nitrogen injection technology, nitrogen has the characteristics of inerting the fire area and wide diffusion range, but nitrogen is easy to flow with air leakage, its ability to extinguish fire and cool down is weak, and the western mining area is buried shallow, the gob area is large, and surface air leakage is serious, making it difficult to form Because of the closed space, nitrogen injection cannot achieve the purpose of reducing the oxygen depth in the goaf to prevent coal spontaneous combustion in the goaf; spraying inhibitors is used to corrode underground equipment and endanger the health of workers, and the diffusion range of inhibitors is limited, making it difficult to enter the upper mining area. Empty area, so the fire prevention effect is very unsatisfactory

The conventional grouting method generally adopts a grouting station at the wellhead of the mine, and the grout is sent to the grouting hole in the underground through the grouting pipeline to grout the upper and lower gobs. The grouting time is as the working face is recovered. , there are the following problems in the prevention of spontaneous combustion of coal in the upper layer and the large-area goaf of this layer in the mining of shallow buried depth and short-distance coal seam groups: 1) Since the coal seam in the western mining area is a near-horizontal coal seam, and the mining strike length is long, the grout for conventional grouting The fluidity is poor, the flow range is limited, and it cannot effectively cover the remaining coal to prevent coal spontaneous combustion in the goaf; 2) The mine field in the western mining area is large and buried shallow, and the working face is far away from the mine wellhead (more than 10km), resulting in grouting of conventional grouting The small double line leads to low grouting pressure in the conventional grouting process, which is easy to block the grouting pipeline and difficult to implement grouting; 3) Due to the shallow buried depth and close-range coal seam groups in the western mining area, the distance between coal seams is small, and the lower layer is mined. It is very easy to cause spontaneous combustion of residual coal in the upper mined-out area, but the conventional upward hole grouting drilling is difficult to implement, the amount of work is large, and it is difficult for the grout to reach the upper mined-out area to prevent spontaneous combustion of residual coal, and the effect is extremely poor

Therefore, the above methods are often unable to effectively prevent the spontaneous combustion of coal in the upper layer and the large-area goaf of this layer in shallow buried depth and short-distance coal seam group mining, which brings difficulties to mine fire prevention and extinguishing.

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