Remining method for residual coal resources of fully mechanized caving mining

Abstract

The invention provides a full-mechanized caving mining remaining coal resource re-mining method, which can improve the coal recovery rate, control the disaster risk in the mining process and guarantee the efficient and economical recovery of re-mining operation, and comprises the following steps of: tunneling a roadway in a goaf of a primary full-mechanized caving mining working face of an adjacent solid thick coal seam; in the roadway tunneling construction process, a roadway reconstruction technology of shallow gel injection and surface spraying is implemented, and a complete roadway with good leakproofness is formed by regenerated coal bodies with multiple broken and air leakage cracks in a goaf around the roadway, and then production systems such as a crossheading and an open-off cut are arranged; a secondary fully-mechanized caving mining technology is adopted to recover coal resources left in a goaf due to top coal caving in primary fully-mechanized caving mining and protective coal pillars left between adjacent working faces, the method is safe and efficient, the coal resources can be fully recovered, the service life of a mine is prolonged, and the economic benefit is increased. The method has important practical significance on sustainable development of mines, improvement of the recovery rate of coal mine resources and creation of economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of coal resource recovery, and in particular to a method for recovering coal resources left over from fully-mechanized caving mining. Background Art

[0002] Coal resources account for about 97% of the total proven fossil energy resources in my country, and are the cornerstone of ensuring the safe and stable supply of energy in my country. As a non-renewable energy source, coal resources have limited reserves. Reducing resource waste and rational mining are important issues to consider in the process of coal mining. Due to early technical conditions, mining process limitations, and insufficient understanding of resource endowment, some mining areas in my country have adopted mining methods such as mining thick and abandoning thin, mining fat and abandoning thin, mining superior and abandoning inferior, and mining easy and abandoning difficult, which has caused serious damage to the integrity of coal seams, resulting in a considerable part of coal not being effectively mined and left in goafs and surrounding areas. These remaining coal resources not only cause serious waste of resources, but also may cause a series of safety and environmental problems such as insufficient roof collapse in goafs, gas accumulation, and increased hidden dangers of mine water hazards. According to incomplete statistics, the reserves of abandoned coal resources nationwide are about 120 billion tons, and the recoverable reserves are about 40.3 billion tons. The resource reserves are huge, among which abandoned resources in thick coal seams are widely distributed. The development of re-mining of abandoned coal will increase my country's recoverable reserves by 30%. With the rapid development of the coal industry, existing mines are on the verge of exhaustion of high-quality coal resources due to small coal kilns, and the service life of mining areas has been sharply shortened. In order to achieve sustainable development of mining areas, it is particularly necessary to study the re-mining of abandoned coal resources. There is an urgent need for a re-mining method that can effectively improve the resource recovery rate, reduce safety risks, and have good economy and operability based on the characteristics of coal resources left over from comprehensive caving mining, so as to achieve sustainable development and utilization of coal resources and ensure safe production and stable operation of mines. Summary of the invention

[0003] The purpose of the present invention is to provide a method for re-mining coal resources left over from fully-mechanized caving mining. The device can solve the problems that existing re-mining technologies are difficult to achieve in improving coal recovery rates, controlling disaster risks during mining, and ensuring high efficiency and economic recovery of re-mining operations.

[0004] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is specifically as follows:

[0005] A method for re-mining coal resources left over from fully-mechanized caving mining comprises the following steps:

[0006] S1. Excavate tunnels in the goaf of the first fully mechanized caving mining face in the adjacent solid thick coal seam;

[0007] S2. During the tunnel excavation construction, the tunnel reconstruction technology of shallow injection gel + surface spraying is implemented to reconstruct the regenerated coal body with broken goaf and many air leakage cracks around the tunnel into a complete and well-sealed tunnel;

[0008] S3. Arrange the return air chute, track chute and equipment required for opening the cutting eye;

[0009] S4. Use secondary fully-mechanized top coal caving technology to recover the coal resources left in the goaf due to top coal collapse in the initial fully-mechanized top coal caving and the protective coal pillars left between adjacent working faces, so as to realize the re-mining of the remaining coal resources and maximize the recovery rate of coal resources.

[0010] Preferably, in step S2, a glue injection drill hole is arranged perpendicular to the top plate at each shoulder of the tunnel within a certain range a in the tunnel; a glue injection drill hole is arranged vertically downward from the top plate at each side of the tunnel, and a group is constructed at a certain interval. During excavation, gel is injected head-on into the constructed glue injection holes to form a gel-enclosed wall in the goaf around the excavation tunnel.

[0011] Preferably, in step S2, a takes a value of 0.8-0.9 m, the outer diameter of the injection drilling hole is not greater than 1.2 m, the elevation angle is 45°, the drilling depth is not less than 2 m, and one group is constructed every 5 m.

[0012] Preferably, in step S3, a return air trench is arranged along the bottom plate in the goaf of the initial fully mechanized caving face, and a track trench is arranged along the bottom plate in the goaf of the adjacent fully mechanized caving face.

[0013] Preferably, in step S4, the secondary fully-mechanized top-caving mining technology is specifically to design the mining height and mining ratio of the secondary fully-mechanized top-caving mining according to the difference in thickness of the compacted regenerated coal seam left in the goaf of the initial fully-mechanized top-caving mining.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) Improve the coal resource recovery rate: The coal resources left in the goaf after the top coal collapse during the initial fully-mechanized top coal mining and the protective coal pillars left between adjacent working faces are effectively recovered. This specifically solves the problem of the difficulty in mining the remaining coal after the previous fully-mechanized top coal mining, which has positive significance for ensuring the long-term stable resource supply of the coal industry.

[0016] (2) Effectively control disaster risks: The tunnel reconstruction technology of shallow injection of gel + surface spraying is implemented to effectively block the possible air leakage channels in the goaf, reduce the risk of spontaneous combustion of coal and gas accumulation in the re-mining working face, and also enhance the stability of the tunnel and surrounding areas, significantly reducing the disaster risk during the mining process.

[0017] (3) Ensure the efficiency of re-mining operations: The whole process of re-mining coal resources left over from comprehensive caving mining is scientifically planned and closely connected, which avoids frequent shutdowns and rework caused by complex geological conditions and other factors, improves the overall efficiency of re-mining work, ensures that coal resources can be recovered in a timely and efficient manner, and helps to improve the production efficiency of coal mines.

[0018] (4) Improving the economic efficiency of re-mining operations: While increasing the coal recovery rate, the additional investment in safety assurance is reduced by effectively controlling disaster risks, and the time, manpower and material costs are reduced by ensuring the efficiency of re-mining operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0020] Figure 1 A schematic diagram of the F1301 working surface layout provided in an embodiment of the present invention.

[0021] Figure 2 It is a schematic diagram of the tunnel reconstruction construction according to an embodiment of the present invention.

[0022] Among them, the accompanying drawings are marked as: 1-re-mining working face, 2-fully-mechanized caving working face Ι, 3-fully-mechanized caving working face ΙΙ, 4-protective coal pillar, 5-track drift, 6-return air drift, 7-opening cutting eye. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0024] Project Overview:

[0025] The F1301 re-mining working face of Yunhe Coal Mine is arranged between the original 1301 and 1302 fully mechanized caving working faces, with the protection coal pillar of the Industrial Square in the east, the XDF23 reverse fault in the west, the 1301 goaf in the north, and the 1302 goaf in the south. The layout of the F1301 working face is shown in the figure below: Figure 1 As shown, the original 1301 and 1302 working faces were mined in November 2000 and May 2007 respectively, and the No. 3 coal seam was mined using the fully mechanized top coal caving mining technology, with average coal seam thicknesses of 9.42m and 8m respectively.

[0026] The F1301 re-mining face mainly mines the No. 3 coal seam, with a residual thickness of 3 to 4 meters, an underground elevation of -440 to -520 meters, and an average of -480 meters. The immediate roof and basic roof are sandy mudstone (1.34 to 4.84 meters), fine sandstone (7.89 to 8.90 meters), and the immediate bottom and basic bottom are mudstone (3.18 to 3.90 meters), and fine sandstone (16.15 to 20.23 meters). The F1301 working face track chute and belt chute both adopt a trapezoidal section, with a net width of 3.324 meters at the top, 4.4 meters at the bottom, a net height of 3.05 meters, and a net section of 11.78 meters. 2 .

[0027] Implementation steps:

[0028] An embodiment of the present invention provides a method for recovering coal resources left over from fully-mechanized caving mining, which specifically comprises:

[0029] Step 1: First, excavate tunnels in the goaf area of ​​the fully mechanized top-caving mining face in the solid thick coal seam, excavate along the bottom plate to arrange the return air drift 6 in the goaf area 2 of the 1301 fully mechanized top-caving face, and excavate along the bottom plate to arrange the track drift 5 in the goaf area 3 of the adjacent 1302 fully mechanized top-caving face, and place the protective coal pillar 4 resources left between the two fully mechanized top-caving faces inside the F1301 secondary mining face 1 to achieve full recovery of the remaining coal resources in the goaf.

[0030] Step 2: During the tunnel excavation construction, the tunnel reconstruction technology of shallow injection of gel + surface spraying is implemented. The gel is shallowly injected into the regenerated coal body with broken goafs and many air leakage cracks around the tunnel to seal and cool down. A glue injection drill hole is arranged perpendicular to the roof within 0.8-0.9m in the tunnel at both shoulders of the tunnel; a glue injection drill hole is arranged vertically at a distance of no more than 1.2m downward from the roof on both sides of the tunnel, with an elevation angle of 45° and a drilling depth of no less than 2m. A group is constructed every 5m. During the excavation, gel is injected head-on into the constructed glue injection holes to form a gel-sealed wall in the goafs around the excavated tunnel, and the regenerated coal body with broken goafs and many air leakage cracks around the tunnel is rebuilt into a complete and well-sealed tunnel. The schematic diagram of the tunnel reconstruction construction is shown as follows Figure 2 shown.

[0031] Step 3: After arranging the production systems such as the track drift 5, the return air drift 6 and the cutting eye 7, design the mining height and mining ratio of the secondary comprehensive top-caving mining according to the difference in thickness of the compacted regenerated coal seam left in the goaf after the initial comprehensive top-caving mining. Use the secondary comprehensive top-caving mining technology to recover the coal resources left in the goaf due to the collapse of the top coal in the initial comprehensive top-caving mining and the protective coal pillar 4 left between adjacent working faces, so as to realize the re-mining of the remaining coal resources and maximize the recovery rate of coal resources.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for recovering coal resources left over from fully mechanized caving mining, characterized in that: The following steps are involved: S1. Excavate tunnels in the goaf of the first fully mechanized caving mining face in the adjacent solid thick coal seam; S2. During the tunnel excavation construction, the tunnel reconstruction technology of shallow injection gel + surface spraying is implemented to reconstruct the regenerated coal body with broken goaf and many air leakage cracks around the tunnel into a complete and well-sealed tunnel; S3. Arrange the return air chute, track chute and equipment required for opening the cutting eye; S4. Use secondary fully-mechanized top coal caving technology to recover the coal resources left in the goaf due to top coal collapse in the initial fully-mechanized top coal caving and the protective coal pillars left between adjacent working faces, so as to realize the re-mining of the remaining coal resources and maximize the recovery rate of coal resources.

2. A method for recovering coal resources left over from fully mechanized caving mining according to claim 1, characterized in that: In step S2, a glue injection drill hole is arranged perpendicular to the roof within a certain range a in the tunnel from both shoulders; a glue injection drill hole is arranged vertically downward from the roof on both sides of the tunnel, and a group of holes is constructed at a certain interval. During excavation, gel is injected head-on into the completed injection holes to form a gel-enclosed wall in the goaf around the excavation tunnel.

3. A method for recovering coal resources left over from fully mechanized caving mining according to claim 2, characterized in that: In step S2, a takes a value of 0.8-0.9 m, the outer diameter of the injection drilling hole is not greater than 1.2 m, the elevation angle is 45°, the drilling depth is not less than 2 m, and one group is constructed every 5 m.

4. The method for recovering coal resources left over from fully-mechanized caving mining according to claim 1 is characterized in that: In step S3, a return air tunnel is arranged along the bottom plate in the goaf of the initial fully mechanized caving face, and a track tunnel is arranged along the bottom plate in the goaf of the adjacent fully mechanized caving face.

5. The method for recovering coal resources left over from fully mechanized caving mining according to claim 1 is characterized in that: In step S4, the secondary fully-mechanized top-caving mining technology is specifically to design the secondary fully-mechanized top-caving mining height and mining ratio according to the difference in thickness of the compacted regenerated coal seam left in the goaf of the initial fully-mechanized top-caving.

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