Non-pillar mining method for hard roof coal wall of thick coal seam

Abstract

The invention discloses a non-pillar mining method for a hard roof coal wall of a thick coal seam. The non-pillar mining method comprises the following steps of: (1) excavating an upper crossheading roadway and a lower crossheading roadway; (2) excavating a roof cutting tunnel; (3) arranging a first roof cutting surface and a second roof cutting surface in the roof cutting tunnel; (4) reinforcing the top of the lower crossheading roadway; (5) backstopping a mining surface, and erecting a support protective layer; (6) blasting to cause a hard roof to fracture along the first roof cutting surface and the second roof cutting surface so that the place of the original lower crossheading roadway forms a roadway again; (7) using the roadway automatically formed at the place of the original lower crossheading roadway as an upper crossheading roadway of the next mining surface; and (8) repeating the steps (2)-(7). According to the non-pillar mining method, the roof in a mined-out area fractures along the first roof cutting surface and the second roof cutting surface through the blasting along a first energy gathering blasting roof cutting hole and a second energy gathering blasting roof cutting hole, simultaneously a lower crossheading roof is prevented from being damaged, and small caving gangues are prevented from entering the lower crossheading roadway so that the place of the original lower crossheading roadway automatically forms the tunnel.

Description

technical field [0001] The invention relates to a coal seam mining method, in particular to the coal seam mining method of a longwall working face under the condition that the thickness of the coal seam exceeds 3.5m and a hard roof. Background technique [0002] At present, in order to increase the speed of advancement and efficient production, large mining height fully mechanized mining (large mining height refers to coal seams with a thickness of more than 3.5m, fully mechanized mining is the abbreviation of comprehensive mechanized coal mining in coal mines, and fully mechanized mining refers to the comprehensive mining of coal mine underground equipment. For the mining face of mechanized equipment, the coal mining equipment used in the mining of this working face is a coal shearer, the transportation equipment of the working face is a flexible scraper conveyor, the roof support of the working face is supported by hydraulic supports, and a belt conveyor is equipped along th...

AI Technical Summary

Problems solved by technology

[0003] 1. When the coal pillar is used to maintain the gob-side roadway, if the coal pillar is too small, the coal pillar can hardly support the pressure of the stope roof, and cannot protect the gob-side roadway. The gob-side roadway is crushed and deformed too much. It cannot be used; if the coal pillar is too large, although it can support the roof pressure of the stope, it will waste a lot of coal resources and cannot be recovered, resulting in resource loss and waste; and leaving a coal pillar will cause coal and gas outburst, impact mine pressure, etc. Severe disasters, resulting in equipment damage and huge casualties, huge potential safety hazards

Therefore, the economy and safety of maintaining the gob-side roadway with coal pillars are poor

[0004] 2. When roadside filling is used to maintain the gob-side roadway, due to the increase of the mining height of the thick coal seam, the activity range of the stope roof overburden increases, the hard roof is difficult to collapse, and the gangue is difficult to fill the goaf, resulting in a larger suspended roof area. The collapse period and distance of the stope are obviously larger than those of the thin coal seam, which will lead to an increase in the pressure of the stope roof on the filling support structure beside the roadway. Therefore, the poured materials must have high strength. The industrial materials for mechanized rapid pouring underground have low strength and are easily crushed, while the newly developed high-water and high-strength quick-setting materials are costly, and the entry retention process system is complicated, which seriously restricts the economic and technical benefits. The application and promotion of this technology has only been tested in a few mines, and has not been promoted.

Therefore, when roadside filling is used to maintain the gob-side roadway, not only the cost is extremely high, but also there is great uncertainty and the safety is not high

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