A fishbone filling coal mining method for upper layered re-mining of thick coal seams

Abstract

The present invention discloses a method for re-mining thick coal seams with upper layer fishbone filling, and relates to the technical field of re-mining and filling thick coal seams in coal mines. When re-mining thick coal seams, the upper layer is mined in advance, and a metal mesh is laid behind the upper layer working face, and fishbone filling is performed in the goaf on the metal mesh. After the upper layer is mined, the lower layer is mined again. When the lower layer is mined again, a 10-20 cm safety layer is reserved on the upper part. The lower layer support and the upper part of the coal wall are supported by the upper layer fishbone filling body to protect the working face from safe mining, and the rear of the working face collapses as it is mined. The coal mining method of the present invention directly performs fishbone-type efficient filling behind the upper layer mining working face support, thereby ensuring the safety and stability of the working face. At the same time, the coal mining efficiency is improved by adopting a long-arm propulsion mining method.

Description

Technical Field

[0001] The invention relates to the technical field of re-mining and filling thick coal seams in coal mines, and in particular to a thick coal seam re-mining upper layer fishbone filling coal mining method. Background Art

[0002] At present, the mining technology used for thick coal seams is mainly stratified mining. Due to technical limitations, many methods of mining the top and abandoning the bottom were used in the mining of extra-thick coal seams, which resulted in a large amount of high-quality coal resources in the lower part of the thick coal seams being wasted. At present, there are two main methods for recovering the remaining coal resources: wall mining and pillar mining. The pillar mining method has the disadvantages of low mechanization, difficulty in excavation and ventilation, and is no longer promoted. The wall mining method often uses top coal caving. Under the current technical level, the coal recovery rate of the working face of top coal caving is generally about 10% lower than that of stratified mining. Even if the non-coal pillar protection technology is adopted, the initial and final mining losses and process losses will still exist, so there are more coal losses. At the same time, top coal caving mining also has the disadvantages of large coal dust, easy spontaneous combustion, a lot of broken coal left in the goaf, the broken coal body is easy to spontaneously combust, and the goaf is easy to cause gas accumulation. Whether coal resources can be fully recovered is the key to the re-mining of thick coal seams.

[0003] In view of the current situation, it is necessary to innovate the mining method of thick coal seams to ensure the safe and efficient mining of coal resources in thick coal seams.

[0004] The relevant research reports in the prior art mainly include:

[0005] CN114412550A discloses a goaf grouting management method for re-mining old goafs in extra-thick coal seams. This method is to drill grouting holes on the ground to fill the goaf space with grouting after the thick coal seam has been re-mined and the roof of the mining area has completely collapsed. This method requires drilling a number of holes on the surface for filling and timely observing the filling situation. The filling process is complicated, the filling effect is not easy to observe, and the cost is relatively high.

[0006] CN109915145A discloses a method for mining coal resources by bureau mining and filling. This method divides the mining block into two wings, alternately arranges mining field branch tunnels and branch tunnel protection coal pillars on the two wings after the division, and fill mining is carried out alternately. However, this method leaves a large number of coal pillars, resulting in a large waste of coal resources. At the same time, the movement of mining field branch tunnels is cumbersome, the mining efficiency is low, and the mining method is uneconomical.

[0007] The above-mentioned existing technologies still have technical problems such as low safety factor of thick coal seam re-mining, low mining efficiency, and cumbersome relocation of mining site branch tunnels. It can be seen that the existing technologies need to be further improved. Summary of the invention

[0008] The purpose of the present invention is to provide a thick coal seam re-mining upper layer fishbone filling coal mining method, which directly performs fishbone type efficient filling behind the upper layer recovery working face support, ensuring the safety and stability of the working face. At the same time, by adopting a long arm propulsion recovery method, the coal mining efficiency is high.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A thick coal seam re-mining upper layer herringbone filling coal mining method comprises the following steps in sequence:

[0011] a. The upper layered working surface is pushed forward, and metal mesh and filling bags are laid on the bottom plate behind the working surface. The metal mesh is laid continuously as the working surface is pushed forward;

[0012] b. When the working surface advances c+1 meter for the first time, it reaches the length of laying a filling bag, and the filling bags are arranged in a fishbone shape, with grouting holes arranged on each filling bag;

[0013] c. After the filling bags are arranged, high-water filling materials are injected into the filling bags through the grouting holes; after the filling bags are filled, the working face continues to advance;

[0014] d. As the working face continues to advance, when it advances c meters again, continue to lay the filling bags, and the filling bags are laid in an overlapping manner of 1 meter with the filling bags when the working face was advanced last time, and the filling bags are arranged in a fishbone shape;

[0015] e. After the filling bags are laid out, high-water filling materials are injected into the filling bags through the grouting holes of the filling bags; after the filling bags are filled, the working face continues to advance;

[0016] f. Repeat step d and step e until the mining of the upper coal seam is completed;

[0017] g. Mine the lower coal seam, and advance the mining face of the lower coal seam normally. Reserve a coal seam of a certain thickness as a safety layer on the upper part of the mining face of the lower coal seam, and arrange hydraulic supports on the mining face of the lower coal seam.

[0018] As a preferred solution of the present invention, the fishbone type includes a first oblique rib portion and a second oblique rib portion, and the angle between the first oblique rib portion and the second oblique rib portion is 15° to 45°.

[0019] As another preferred embodiment of the present invention, the length of the first oblique rib portion and the second oblique rib portion is a meters, which is calculated according to formula (1)

[0020]

[0021] Preferably, in step g, a coal seam thickness of 10 to 20 cm is reserved as a safety layer.

[0022] Preferably, the width of the filling body is the same as the width of the working surface, and the spacing between adjacent filling bodies is defined as c meters, which is calculated according to formula (2)

[0023]

[0024] Preferably, the main raw materials of the high-water filling material are fly ash, cement, quicklime, gypsum, foaming agent and water.

[0025] Compared with the prior art, the present invention brings the following beneficial technical effects:

[0026] The present invention proposes a method for mining thick coal seams by using fishbone-type filling in the upper layer during re-mining. When mining thick coal seams, the upper layer is mined in advance, and a metal mesh is laid behind the upper layer working face, and filling is carried out in the goaf on the metal mesh. In terms of filling method, a combination of "fishbone-type filling" and "high-water filling material" is adopted. The fishbone-type filling has better stability. When mining the lower layer coal seams, the filling bags of the fishbone-type filling are laid in an overlapping manner of 1 meter with the filling bags when the previous working face was advanced, thereby enhancing the stability of the working face. The high-water filling material can achieve rapid filling and further improve the coal mining efficiency.

[0027] The present invention proposes a thick coal seam re-mining upper layer fishbone filling coal mining method, which adopts the method of first mining the upper layer, and further improves the filling method by mining and filling at the same time. In the case of mining and filling the upper layer, when the lower layer is mined, the working face is more stable; further, by arranging hydraulic supports on the mining working face of the lower coal seam, the stability of the working face is further enhanced.

[0028] Compared with the goaf grouting treatment method for re-mining old goaf areas of extra-thick coal seams disclosed in CN114412550A, the present invention directly fills behind the working face during upper layer re-mining, avoiding the complexity of the goaf space caused by the sinking and collapse of the overburden in the mining area. The filling is convenient and quick to implement, while ensuring the safety and stability of the working face and effectively controlling ground pressure activities. Compared with the mining method of coal resources bureau mining and filling in a mine disclosed in CN109915145A, the present invention advances mining through the long wall of the working face, and has the advantages of high coal mining efficiency, high recovery rate, less waste of coal, and no need to move the working face; in particular, the high water filling and herringbone-shaped filling bags are used to achieve high filling efficiency.

[0029] In summary, the present invention proposes a thick coal seam re-mining upper layered fishbone filling coal mining method, which not only ensures the stability of the working face, but also improves the coal mining efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described below in conjunction with the accompanying drawings:

[0031] Figure 1 A top view of the upper layered herringbone filling coal mining of the present invention;

[0032] Figure 2 It is a front view of the upper layered herringbone filling coal mining of the present invention;

[0033] Figure 3 This is a front view of the lower layered herringbone filling coal mining of the present invention;

[0034] Figure 4 This is a schematic diagram of a herringbone-shaped filling bag of the present invention;

[0035] In the figure:

[0036] 1. The front part of the fishbone filling body, 2. The tail part of the fishbone filling body, 3. The fishbone filling body, 4. The metal mesh, 5. The safety layer. DETAILED DESCRIPTION

[0037] The present invention proposes a thick coal seam re-mining upper layered fishbone filling coal mining method. In order to make the advantages and technical solutions of the present invention clearer and more specific, the present invention is further described below in conjunction with specific embodiments.

[0038] The "fishbone type" described in the present invention includes a first oblique rib portion and a second oblique rib portion with an angle of 15° to 45°. Figure 1 The front part 1 of the fishbone filling body shown in FIG. 1 is the other end of the two ribs away from the angle. Figure 1 The tail portion 2 of the fishbone filling body shown in the figure, the first oblique rib portion and the second oblique rib portion constitute the fishbone filling body 3. Since its overall structure resembles a "fishbone", it is called a fishbone-type filling body.

[0039] The fillings described in the present invention are all herringbone fillings.

[0040] The main raw materials of the high-water filling material mentioned in the present invention are fly ash, cement, quicklime, gypsum, foaming agent and water.

[0041] Combination Figures 1 to 4 As shown, the present invention provides a thick coal seam multiple mining upper layer fishbone filling coal mining method, and its general steps are:

[0042] When re-mining thick coal seams, the upper layer is mined in advance, and a metal mesh is laid behind the upper layer working face, and herringbone filling is performed in the goaf on the metal mesh. After the upper layer is mined, the lower layer is mined again. When re-mining the lower layer, a 10-20 cm safety layer is reserved on the upper part. The lower layer support and the upper part of the coal wall are supported by the upper layer herringbone filling body to protect the safe mining of the working face, and the back of the working face collapses as it is mined.

[0043] The width of the fishbone filling body is the width of the working surface, b meters. The angle is α, which can be 15° to 45°. The length of the fishbone on one side is a meter, which can be calculated according to formula (1)

[0044] The spacing between the filling bodies is c meters Calculated according to formula (2).

[0045] The herringbone type filling body is a herringbone type filling bag arranged behind the working face. When the working face is advanced c meters, the herringbone type filling bag is filled with high-water filling material.

[0046] The safety layer is 10 to 20 centimeters and is left on the upper part of the lower layer to protect the coal cutter and hydraulic support from being affected by the upper filling body.

[0047] Embodiment 1:

[0048] The specific recovery steps are:

[0049] Step 1: The upper layered working surface is advanced forward, and metal mesh and filling bags are laid on the bottom plate behind the working surface. The metal mesh is laid continuously as the working surface is advanced;

[0050] Step 2: When the working surface advances for the first time (c+1) meters, reaching the length of the first filling bag, the herringbone filling bag is laid out;

[0051] Step 3: After the filling bag is laid, high-water filling material is injected through the grouting holes of the herringbone filling bag. After the filling bag is filled, the working face continues to advance;

[0052] Step 4: As the working surface continues to advance, when it advances c meters again, continue to lay herringbone filling bags, and the filling bags are laid in an overlapping manner with the previous filling bags for 1 meter;

[0053] Step 5: After the filling bags are laid out, high-water filling materials are injected through the grouting holes of the herringbone filling bags. After the filling bags are filled, the working face continues to advance;

[0054] Step 6: Repeat steps 4 and 5 until the upper coal seam is mined;

[0055] Step 7: After the upper coal seam is mined, the lower coal seam is mined, and the lower coal seam mining face is advanced normally. A 10-20 cm safety layer is left on the upper part of the working face to protect the hydraulic support and the coal mining machine drum. The rear of the working face collapses as it is mined.

[0056] Parts not described in the present invention can be implemented by referring to the existing technology.

[0057] It should be noted that any equivalent method or obvious variation method made by those skilled in the art under the guidance of this specification should be within the protection scope of the present invention.

Claims

1. A thick coal seam re-mining upper layer herringbone filling coal mining method, characterized in that: The following steps are included in sequence: a. The upper layered working surface is pushed forward, and metal mesh and filling bags are laid on the bottom plate behind the working surface. The metal mesh is laid continuously as the working surface is pushed forward; b. When the working surface advances c+1 meter for the first time, it reaches the length of laying a filling bag, and the filling bags are arranged in a fishbone shape, and grouting holes are arranged on each filling bag; c. After the filling bags are arranged, high-water filling materials are injected into the filling bags through the grouting holes; after the filling bags are filled, the working face continues to advance; d. As the working face continues to advance, when it advances c meters again, continue to lay the filling bags, and the filling bags are laid in an overlapping manner of 1 meter with the filling bags when the working face was advanced last time, and the filling bags are arranged in a fishbone shape; e. After the filling bags are laid out, high-water filling materials are injected into the filling bags through the grouting holes; after the filling bags are filled, the working face continues to advance; f. Repeat steps d and e until the mining of the upper coal seam is completed; g. Mining the lower layer coal seam, the lower layer coal seam mining working face is advanced normally, a certain thickness of coal seam is reserved on the upper part of the lower layer coal seam mining working face as a safety layer, and hydraulic supports are arranged on the lower layer coal seam mining working face; In step d, the fishbone shape includes a first oblique rib portion and a second oblique rib portion, and the angle between the first oblique rib portion and the second oblique rib portion is 15° to 45°; the angle between the first oblique rib portion and the second oblique rib portion is the front part of the fishbone filling body, and the other end of the two rib portions away from the angle is the tail part of the fishbone filling body, and the first oblique rib portion and the second oblique rib portion constitute the fishbone filling body.

2. The thick coal seam re-mining upper layer herringbone filling coal mining method according to claim 1 is characterized by: The length of the first oblique rib portion and the second oblique rib portion is a meter, which is calculated according to formula (1): In formula (1), ɑ is the angle between the first oblique rib portion and the second oblique rib portion.

3. The thick coal seam re-mining upper layer herringbone filling coal mining method according to claim 1 is characterized by: In step g, a coal seam thickness of 10 to 20 cm is reserved as a safety layer.

4. The thick coal seam re-mining upper layer herringbone filling coal mining method according to claim 1 is characterized by: The width of the herringbone filling body is the same as the width of the working surface. The spacing between adjacent filling bodies is defined as c meters, which is calculated according to formula (2): In formula (2), ɑ is the angle between the first oblique rib portion and the second oblique rib portion.

5. The thick coal seam re-mining upper layer herringbone filling coal mining method according to claim 1 is characterized by: The main raw materials of the high-water filling material are fly ash, cement, quicklime, gypsum, foaming agent and water.

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