A coal-pillar-free mining method for confining concrete pillars in thick coal seams

Abstract

The invention discloses a coal-pillar-free mining method with thick coal seam-constrained concrete pillars, the main principle of which is to cancel the layout of coal pillars, and adopt advanced cracking and broken roofs and constant resistance anchors in the trough of the previous working face. Cable-steel belt support, strong support in the strong dynamic pressure zone and combined roof cutting of the cracks and cracks, retractable gangue support in the strong dynamic pressure zone, shrinkable restraint concrete pillars to support the roof in the slow-release and anti-deformation zone, and stable zone Using methods such as microcapsule inhibitor slow-release foam material to close the gangue gangue beside the roadway, realize the pressure relief of the goaf roadway roof pre-cracking and breaking the roof before mining, combined roof cutting and filling roadside after mining, and shrinkable strong pillars to support the short arm of the roof cutting Roof and roadside strong and flexible materials are used to seal and prevent air leakage, etc., realizing coal pillar-free mining, which is a more scientific and reasonable coal mining layout method.

Description

technical field [0001] The invention belongs to the technical field of coal-pillar-free mining, and in particular relates to a coal-pillar-free mining method for thick coal seam-constrained concrete pillars with top-cutting and roadway formation. Background technique [0002] Among the existing coal reserves and production in my country, the production and reserves of thick coal seams (5.0m≥thickness≥2.5m) both exceed 50%, and thick coal seams are the main coal seams to achieve high-yield and efficient mining in my country, which have advantages in resource reserves, such as Jin Coal Group, Coking Coal Group, Tongmei Group and other large mining enterprises mainly mine thick coal seams above 2.5m to 5.0m. 60m coal pillar, resulting in low coal recovery rate, coal pillar loss accounted for as high as 54.59% to 64.23%, resulting in serious waste of resources. At the same time, the layout of the excavation system with two lanes on one side leads to problems such as large excavat...

AI Technical Summary

Problems solved by technology

Among them, the roadside filling wall mining mainly realizes coal pillar-free mining by filling high-water materials, concrete, paste and other materials with a width of 1.5m to 3.0m beside the roadway to replace the coal pillars between sections. Column mining, the roadside masonry wall can support the roadway roof, but there are many insurmountable problems that limit its large-scale application. The main problems include: large amount of filling materials at the side of the roadway, difficulty in transporting materials and occupying the capacity of the transportation system, It has a great impact on production and transportation; the process of filling the wall behind the support is complicated, which restricts the advancement speed of the working face and cannot achieve rapid mining; the early strength of the filling wall is low, and the strength growth is slow. To achieve sufficient support strength, it will be crushed and destroyed by the roof of the stope; complex filling pipeline system and filling equipment are required, occupying the working space of the tunnel roadway and working face, resulting in complex management system and many hidden danger points; filling pipeline and filling equipment Filling equipment requires a one-time investment of more than 4 million yuan, which is expensive, and the filling material per meter is as high as 10,000 to 20,000 yuan. Huge equipment and material investment failure risk caused by unsatisfactory results

At present, this technology has been widely used below 2.5m, but it has not been successfully applied in thick coal seams above 2.5m to 5.0m. Only when the mining height is more than 4 times can the stable rock formation be achieved, that is, the length of the anchor cable must be more than 12m. If the thickness of the coal seam reaches 4m, the length of the anchor cable must be at least 16m. Excellent cost and high support effect, but when it exceeds 10m, there will be prominent problems such as slow support speed, difficult anchoring, and high support cost. At the same time, after the mining thickness increases, the strength of the roof support is required. The density of the anchor cables is high, which is difficult to realize underground, which makes the technology of roof cutting, pressure relief and gob-side entry retention unable to be successfully applied in thick coal seams

In addition, the mining height of thick coal seam is large. After the coal seam is mined, the goaf space is large. The large mining height causes the range of activities of the stope roof overburden to increase. When the hard roof in the overburden is pressed, the suspended roof area is large, which will bring huge The stope pressure makes it difficult to maintain the gob-side roadway

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