Coal mining method

Abstract

The present application provides a kind of coal mining method.The coal mining method includes: step one: analyzing the characteristics of the coal seam to be mined, determining the structural strength σe of the paste, designing the step distance L of the filled paste and the height H of the filled paste;Step two: the coal seam to be mined is pre-mined to form a first to be mined area and a second to be mined area, and a roadway is arranged to form an air intake and return system;Step three: a heading machine is arranged to sequentially mine the first to be mined area and the second to be mined area, and the roof is supported by anchor rods or anchor cables during mining, and the mined-out roadway is sealed;Step four: filling the paste into the mined-out roadway;Step five: repeating steps three to four until the mining of the coal seam to be mined is completed.The present application solves the problem of coal seam falling and reducing mining efficiency in deep coal mining in the prior art.

Description

Technical Field

[0001] This invention relates to the field of mining technology, and more specifically, to a method for coal mining. Background Technology

[0002] In recent years, with the frequent and in-depth development of mining activities in China, mining areas have gradually shifted deeper into the earth's strata. This has not only significantly increased the difficulty of mining operations but also exacerbated the problem of ground subsidence, posing a major threat to the ecological environment and the lives of surrounding residents. Ground subsidence after coal mining not only affects surface stability and soil fertility but may also lead to environmental problems such as water pollution and frequent geological disasters, seriously impacting sustainable development. Furthermore, long-term mining has led to the depletion of shallow resources. The high production costs and complex safety challenges associated with developing deep resources have become key factors restricting the development of the mining industry. Existing mining technologies, such as the longwall mining method, are characterized by a long working face. The coal seam roof and overlying strata naturally collapse after mining to release pressure. However, this method often leads to increased uncontrollability of strata damage, an expanded area of ​​ground subsidence, and a more severe impact on surface buildings and the natural ecosystem. Especially under deep mining conditions, the fracturing and collapse of the overlying strata not only affect mining efficiency, but also increase the costs of mine ventilation, drainage and support, posing a challenge to the economic benefits and safe production of mining enterprises.

[0003] As can be seen from the above, existing technologies have the problem of coal seam detachment during deep coal mining, which reduces mining efficiency. Summary of the Invention

[0004] The main objective of this invention is to provide a coal mining method to solve the problem of coal seam collapse and reduced mining efficiency in deep coal mining in the prior art.

[0005] To achieve the above objectives, the present invention provides a coal mining method, comprising: Step 1: analyzing the characteristics of the coal seam to be mined and determining the structural strength σ of the paste. e Step 1: Design the step distance L and filling height H of the paste; Step 2: Pre-min the coal seam to be mined to form a first mining area and a second mining area, and arrange roadways to form an intake and return air system; Step 3: Arrange the tunneling machine to mine the first mining area and the second mining area in sequence, and support the roof with anchor bolts or anchor cables during the mining process, and seal the goaf roadway after mining; Step 4: Fill the goaf roadway with paste; Step 5: Repeat steps 3 to 4 until the mining of the coal seam to be mined is completed.

[0006] Furthermore, step three, which involves deploying tunneling machines to sequentially mine the first and second mining areas, includes: deploying multiple tunneling machines, wherein the multiple tunneling machines mine the first mining area at intervals of step L for a preset distance and then stop, and then move to the second mining area to mine, and stop after mining the preset distance; adjusting the working content of the tunneling machines, selecting one of the multiple tunneling machines to perform a secondary bottom-filling to open up the multiple mining roadways formed by the first and second mining areas in one mining operation to form multiple goaf roadways.

[0007] Furthermore, step three also includes temporarily sealing the mining roadway, with a reserved coal seam at one end and a sealing element at the other end to seal the other end of the mining roadway, so as to avoid the tunneling machine during the second bottoming process; and / or a reserved coal seam at one end of the mining roadway and a sealing element at the other end, the sealing element being connected to the goaf roadway to seal the other end of the mining roadway.

[0008] Furthermore, step three also includes pre-burying filler pipes in the goaf before sealing the goaf roadway, and the filler pipes are movable and set in the goaf roadway.

[0009] Furthermore, adjusting the working content of the tunneling machines also includes setting at least one of the multiple tunneling machines on one of the first and second mining areas, and setting the remaining tunneling machines on the other of the first and second mining areas.

[0010] Furthermore, when the tunneling machine is mining in the first or second mining area, the tunneling speed of the tunneling machine is V1, and the speed of the tunneling machine when it is performing the second bottom-covering is V2, wherein V1 is less than V2.

[0011] Furthermore, step four involves filling the goaf roadway with paste by injecting the paste into the goaf roadway in stages.

[0012] Furthermore, in step one, the strength σ of the filling body... e The height H is determined by the following formula: Where: H - height of cemented infill, m; σe - self-supporting strength of cemented infill, MPa; a - empirical coefficient; filling step distance L is determined by the following formula: Where: σ e -Self-supporting strength of the filling material, MPa; γ c -Bulk density of cemented filler, MN·m -3 H - Height of cemented filler, m; L - Filling step distance, m.

[0013] Furthermore, step five also includes finishing and filling the coal seam to be mined.

[0014] Furthermore, step three also includes pre-burying exhaust pipes in the goaf roadway.

[0015] The coal mining method according to the technical solution of this invention includes: Step 1: Analyzing the characteristics of the coal seam to be mined and determining the structural strength σ of the paste. e Step 1: Design the step distance L and filling height H of the paste; Step 2: Pre-min the coal seam to be mined to form a first mining area and a second mining area, and arrange roadways to form an intake and return air system; Step 3: Arrange the tunneling machine to mine the first mining area and the second mining area in sequence, and support the roof with anchor bolts or anchor cables during the mining process, and seal the mined goaf roadway; Step 4: Fill the goaf roadway with paste; Step 5: Repeat steps 3 to 4 until the mining of the coal seam to be mined is completed, by dividing the coal seam to be mined into two areas. The process of sequentially mining the first and second mining areas, and promptly sealing and filling the goaf with paste, effectively ensures support for the coal seam roof, avoiding the risks of coal seam breakage, collapse, or even surface deformation in the mining areas. This ensures mining efficiency, and the separate operation of coal seam mining and paste filling further guarantees efficiency. This solves the problem of coal seam detachment reducing mining efficiency in deep coal mines, which is common in existing technologies. Furthermore, the paste filling method after mining improves safety during the mining process. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0017] Figure 1 A flowchart of a coal mining method according to a specific embodiment of the present invention is shown; and

[0018] Figure 2 This diagram illustrates a structural schematic of mining a first mining area according to a specific embodiment of the present invention.

[0019] Figure 3 This diagram illustrates the structure of the first mining area in a specific embodiment of the present invention.

[0020] Figure 4 This diagram illustrates a specific embodiment of the invention, showing the injection of paste into a goaf roadway.

[0021] Figure 5 This diagram illustrates a structural schematic of a goaf roadway in a first mining area, according to a specific embodiment of the present invention.

[0022] Figure 6 This diagram illustrates a structural schematic of multiple mining operations filling the first mining area in a specific embodiment of the present invention.

[0023] Figure 7 A schematic diagram of the final state in a coal mining method according to a specific embodiment of the present invention is shown.

[0024] The above figures include the following reference numerals:

[0025] 10. Paste; 20. First unmined area; 30. Second unmined area; 40. Tunneling machine; 50. Reserved coal seam; 60. Goaf roadway; 70. First roadway; 80. Second roadway; 90. Third roadway; 100. Ventilation duct; 110. Packing pipe; 120. Sealing component; 130. Fan; 140. Coal transport direction; 150. Air intake direction; 160. Exhaust direction. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0028] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0029] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0030] To address the problem of coal seam collapse reducing mining efficiency during deep coal mining in existing technologies, this invention provides a coal mining method.

[0031] like Figure 1 As shown, the coal mining method includes: Step 1: Analyze the characteristics of the coal seam to be mined and determine the structural strength σ of the paste 10. eStep 1: Design the step distance L and the height H of the filling paste 10; Step 2: Pre-min the coal seam to be mined to form a first mining area 20 and a second mining area 30, and arrange roadways to form an intake and return air system; Step 3: Arrange the tunneling machine 40 to mine the first mining area 20 and the second mining area 30 in sequence, and support the roof with anchor bolts or anchor cables during the mining process, and seal the mined goaf roadway 60; Step 4: Fill the goaf roadway 60 with paste 10; Step 5: Repeat steps 3 to 4 until the mining of the coal seam to be mined is completed.

[0032] By dividing the coal seam to be mined into two areas, mining the first mining area 20 and the second mining area 30 in sequence, and timely sealing and filling of the goaf roadway 60 with paste 10, the support of the coal seam roof can be effectively guaranteed, avoiding the risk of coal seam fracture, collapse or even surface deformation in the mining area, thus ensuring mining efficiency. Moreover, the mining of the coal seam and the filling of paste 10 are carried out separately without interference, which further ensures mining efficiency. At the same time, the method of filling paste 10 after mining is completed can improve the safety of the mining process.

[0033] In this embodiment, step three, which involves deploying tunneling machines 40 to sequentially mine the first mining area 20 and the second mining area 30, includes: deploying multiple tunneling machines 40, wherein each tunneling machine 40 mines the first mining area 20 at intervals of step L for a preset distance before stopping, and then moves to the second mining area 30 to mine, where it mines for the same preset distance before stopping. The working content of the tunneling machines 40 is adjusted, and one of the multiple tunneling machines 40 is selected to perform a secondary bottom-filling operation to connect the multiple mining roadways formed by the first mining area 20 and the second mining area 30 in the first mining operation, thus forming multiple goaf roadways 60.

[0034] Specifically, multiple tunneling machines 40 are spaced apart along the first mining area 20 or the second mining area 30. They move from one end of the first mining area 20 or the second mining area 30 to the other end to carry out mining, and stop tunneling at a position 5m away from the other end. Then they withdraw from the mined area and temporarily seal the opening of the mined area.

[0035] like Figures 2 to 7 As shown, a first tunnel 70 is provided at the top of the first area to be mined 20. The first tunnel 70 is used to discharge polluted air generated during the mining process. A sealing member 120 is used to seal the openings of each area to be mined. During the mining process, one end of the ventilation duct 100 is connected to the blower 130, and the other end is mounted on the tunneling machine 40 and moves with it. The ventilation duct 100 is used to discharge polluted air generated during the mining process by the tunneling machine 40. Figures 2 to 7As shown in the exhaust direction 160, polluted air is discharged from the first roadway 70, while clean air enters the mining area from the second roadway 80 or the third roadway 90, thus forming a complete flow path throughout the entire coal seam to be mined. Clean air enters the coal seam to be mined from the second roadway 80 or the third roadway 90 along the intake direction 150, carrying away the dust generated by the tunneling machine 40 and discharging it along the exhaust direction 160, preventing the generation of a large amount of smoke and dust during the mining process from interfering with the mining progress.

[0036] In this embodiment, step three also includes temporarily sealing the mining roadway. A reserved coal seam 50 is provided at one end of the mining roadway, and a sealing component 120 is provided at the other end of the mining roadway to seal the other end of the mining roadway so as to avoid the tunneling machine 40 during the second bottoming process; and / or a reserved coal seam 50 is provided at one end of the mining roadway, and a sealing component is provided at the other end of the mining roadway. The sealing component is connected to the goaf roadway 60 to seal the other end of the mining roadway.

[0037] Specifically, the sealing element 120 is movably installed at one end of the mining roadway, allowing the roadway to be excavated into a goaf roadway 60 to avoid the tunneling machine 40. The movable installation of the sealing element 120 is quick and easy to operate and recycle. Alternatively, a sealing element can be used to seal the opening of the mining roadway. Optionally, the sealing element is a concrete layer. Using a sealing element improves the sealing effect of the mining roadway, preventing the reserved coal seam 50 from collapsing due to airflow, thus avoiding deformation of the mining roadway and potential safety accidents. When a concrete layer is used to seal the mining roadway, the tunneling machine 40 opens both the sealing element and the reserved coal seam 50, forming the goaf roadway 60. The mined coal seam is then transported out along the coal transport direction 140.

[0038] Furthermore, a 50-ton coal seam is reserved as a wind wall for regulating air volume. It will be opened up during the second bottom pulling to form a full negative pressure ventilation in the mining roadway. The negative pressure ventilation method can improve the exhaust effect.

[0039] In this embodiment, the length of the plugging component 120 or the sealing component is less than the width of the mining tunnel, thereby saving the materials required for construction.

[0040] like Figures 4 to 7 As shown, step three also includes pre-burying a filler pipe 110 in the goaf roadway 60 before sealing it. The filler pipe 110 is movably installed in the goaf roadway 60.

[0041] Specifically, the packing tube 110 extends into one end of the goaf roadway 60, and the length of the packing tube 110 extending into the goaf roadway 60 should not be too long. After the filling of the paste 10 is completed, the packing tube 110 needs to be slowly pulled out and transferred to another goaf roadway 60. Pulling out an excessively long packing tube 110 will take too long. The sealing member 120 is provided with a clearance notch to avoid the packing tube 110, so as to facilitate the removal of the packing tube 110. Furthermore, the sealing member 120 is a structure cast at both ends of the goaf roadway 60, thereby sealing both ends of the goaf roadway 60 and preventing the injected paste 10 from flowing out. Optionally, an outer ring is fitted on the outer end of the packing tube 110, and the sealing member 120 is formed to the outer side of the outer ring. When the packing tube 110 is pulled out, the outer ring remains in the sealing position.

[0042] In this embodiment, adjusting the working content of the tunneling machine 40 also includes setting at least one tunneling machine 40 on one of the first mining area 20 and the second mining area 30, and setting the remaining tunneling machines 40 on the other of the first mining area 20 and the second mining area 30.

[0043] Specifically, there are three tunneling machines 40. Two tunneling machines 40 are used to complete one tunneling operation in the first mining area 20 and the second mining area 30 in turn. After the tunneling is completed, one end of the mining roadway is temporarily sealed. Then, the third tunneling machine 40 starts the second bottoming operation, so that at least one of the multiple tunneling machines 40 can perform the second bottoming operation.

[0044] It should be noted that tunneling refers to the tunneling machine 40 mining the coal seam at a predetermined distance in the first mining area 20 or the second mining area 30, forming a reserved coal seam 50. Secondary bottom clearing refers to the tunneling machine 40 mining the reserved coal seam 50 to form a goaf roadway 60.

[0045] In this embodiment, when the tunneling machine 40 is mining in the first mining area 20 or the second mining area 30, the tunneling speed of the tunneling machine 40 is V1, and the speed of the tunneling machine 40 when performing the second bottom-finishing is V2, wherein V1 is less than V2.

[0046] Specifically, by limiting the speed of tunneling and secondary bottoming of the tunneling machine 40, it is possible to have two tunneling machines 40 simultaneously tunneling and one tunneling machine 40 performing secondary bottoming at any given time. Preferably, the secondary bottoming speed V2 is twice the tunneling speed V1. This means that when two tunneling machines 40 are tunneling in the area to be mined and have reached halfway through the area, the third tunneling machine 40 has already completed the secondary bottoming of one goaf roadway 60. Thus, while two tunneling machines 40 are tunneling two goaf roadways, the third tunneling machine 40 has already completed the secondary bottoming of two goaf roadways 60. This significantly improves construction speed and meets the requirements of the "Safety Regulations".

[0047] like Figure 3 As shown, after completing one mining operation in the first mining area 20 and the second mining area 30, two tunneling machines 40 are always in operation, and one tunneling machine 40 is in operation for the second bottoming. After the second bottoming is completed, the two ends of the goaf roadway 60 are sealed and the paste 10 is filled through the pre-embedded filling pipe 110.

[0048] In this embodiment, step four, filling the goaf roadway 60 with paste 10, includes injecting the paste 10 into the goaf roadway 60 in stages.

[0049] Specifically, a phased filling method is adopted, dividing the entire filling process into two steps. This gradual filling method avoids excessive amounts of paste 10, which could solidify and exceed the area to be mined or cause significant compression on both sides of the goaf roadway 60. Optionally, paste 10 is first filled to a height of 1.5–2.5 m at the bottom of the goaf roadway 60. After the lower part of the paste 10 has initially solidified, filling of the goaf roadway 60 continues until the paste 10 reaches the upper area and touches the roof. After filling is completed, the length of paste 10 is matched to the length of the entire area to be mined.

[0050] In this example, the strength σ of the paste in step one is 10. e The height H is determined by the following formula: Where: H - height of paste 10, m; σe - self-supporting strength of paste 10, MPa; a - empirical coefficient; filling step distance L is determined by the following formula: Where: σ e -Self-supporting strength of paste 10, MPa; γ c -Ointment density 10, MN·m -3 H - Height of paste 10, m; L - Filling distance, m.

[0051] The above formula is used to determine the strength height and spacing of the paste 10 to be filled, thereby ensuring the construction effect.

[0052] In this embodiment, step five also includes finishing and filling the coal seam to be mined.

[0053] Specifically, the bottom finishing process is the secondary bottom finishing process, which does not require roof support. Compared with tunneling, the secondary bottom finishing process at the same working position has one less support procedure. Judging from the time consumed by each procedure, the support procedure accounts for about half the time of a single work cycle. Therefore, the advancement speed of the secondary bottom finishing process is about twice the tunneling speed. Before filling the paste 10, the paste 10 is shaped on the ground and transported to the goaf roadway 60 through the filling pipe 110. The filling pipe 110 is made of wear-resistant material to reduce wear during use.

[0054] In this embodiment, step three also includes pre-burying an exhaust pipe in the goaf roadway 60.

[0055] Specifically, when filling paste 10, the paste 10 condenses and occupies the space inside the goaf roadway 60, and the air inside the goaf roadway 60 is discharged through the exhaust pipe.

[0056] In the coal mining method of the present invention, each area to be mined is a working face, and the working face is along... Figure 1 The right side in the horizontal direction is the cut-in point. During the mining process, the overburden load needs to be slowly and evenly transferred to the goaf 10. The design divides the entire coal seam mining process into three stages: The first stage is the first round of coal seam mining and the filling stage of the goaf roadway 60. The design involves mining adjacent working faces sequentially, leaving a strip of coal pillar of a certain size between the two goaf areas, and then starting the filling after mining. To ensure good ventilation of the working face, a continuous miner is used as the tunneling machine 40 for mining, and a forward-moving arrangement is used for filling until the entire working face is mined and filled. The second stage is the multi-round coal pillar mining and goaf roadway 60 filling stage, which is carried out immediately after mining. To ensure good ventilation of the working face, a forward-moving arrangement is also used for filling until the entire working face is mined and filled. The third stage is the completion of the filling mining stage of the goaf 10. At this time, after multiple rounds of continuous miner strip mining and goaf filling, the coal body of this coal seam is recovered.

[0057] Specifically, starting from the first mining operation, as mining progresses, a paste body 10 is constructed at regular intervals along the strip arrangement direction within the coal seam. If the spacing of the paste bodies 10 is less than the initial fracture step distance of the main roof, and if the spacing of the paste bodies 10 is greater than the initial collapse step distance of the immediate roof, then the immediate roof will fracture and may collapse. The initial collapse step distance of the immediate roof is generally related to the strength, layer thickness, and degree of joint and fracture development of the immediate roof strata. Before the initial collapse, the immediate roof undergoes bending deformation, which is generally greater than the deformation of the main roof, thus easily leading to delamination between the immediate and main roofs. After the immediate roof collapses and breaks, its volume will expand, and its shape and mechanical properties will be equivalent to loose material. The broken immediate roof blocks will accumulate in the unfilled strips, and the height of the accumulation will be higher than the original thickness of the immediate roof. If the collapsed immediate roof fills the unfilled goaf 60, the gangue in the collapsed coal seam will exert horizontal pressure on the two sides of the grit body 10, changing the stress state of the grit body 10 from uniaxial stress to biaxial stress, thereby increasing the bearing capacity of the grit body 10. The bending deformation of the old roof will be very small, producing only a few cracks and maintaining its layered structure. If the collapsed immediate roof does not fill the unfilled goaf 60, the old roof will experience significant bending deformation. When the spacing of the grit bodies 10 is greater than the initial fracture step of the old roof, as the longwall face advances, the immediate roof will collapse first, while the old roof will remain exposed. At this point, the old roof can be considered a "plate" structure. According to thin plate theory, as the bending moment increases, the old roof will fracture when it reaches its strength limit.

[0058] Furthermore, the working face is divided into groups at regular intervals parallel to the cut, and each group is mined and backfilled in four rounds. Coal is cut using EBZ160 or EBZ200 type roadheaders, loaded with coal by loaders, transported by secondary conveyors, and transported by scraper conveyors or rubber-tired vehicles. The roof of the goaf roadway is managed by full backfilling, and the return roadway is left along the goaf.

[0059] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: The coal mining method includes: Step 1: Analyzing the characteristics of the coal seam to be mined and determining the structural strength σ of the paste 10. eStep 1: Design the step distance L and the height H of the filling paste 10; Step 2: Pre-min the coal seam to be mined to form a first mining area 20 and a second mining area 30, and arrange roadways to form an intake and return air system; Step 3: Arrange the tunneling machine 40 to mine the first mining area 20 and the second mining area 30 in sequence, and support the roof with anchor bolts or anchor cables during the mining process, and seal the mined goaf roadway 60; Step 4: Fill the goaf roadway 60 with paste 10; Step 5: Repeat steps 3 to 4 until the mining is completed. The mining of coal seams involves dividing the coal seam to be mined into two areas, mining the first mining area 20 and the second mining area 30 in sequence, and timely sealing and filling of the goaf roadway 60 with paste 10. This effectively ensures the support of the coal seam roof, avoids the risk of coal seam fracture, collapse, or even surface deformation in the mining area, and ensures mining efficiency. Furthermore, the mining of coal seams and the filling of paste 10 are carried out separately without interference, which further ensures mining efficiency. At the same time, the method of filling paste 10 after mining is completed can improve the safety of the mining process.

[0060] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0061] It should be noted that the terms "upper" and "lower," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of coal mining, characterised by, The method comprises the following steps: Step one: analyze the characteristics of the coal seam to be mined, determine the structural strength σ of the paste (10) e , design the step distance L of the filled paste (10) and the height H of the filled paste (10); The paste (10) has a structural strength σ e The height H is determined by the following calculation: ； The step distance L is determined by the following calculation formula: ； where: H - height of the paste (10), m; σe - structural strength of the paste (10), MPa; a - empirical coefficient; c - bulk density of the paste (10), MN m -3 ; L - step, m; Step two: pre-mining the coal seam to be mined to form a first area to be mined (20) and a second area to be mined (30), and arranging a roadway to form an air intake and return system; Step three: arranging a heading machine (40) to sequentially mine the first area to be mined (20) and the second area to be mined (30), supporting the roof with anchor rods or anchor cables during the mining process, and sealing the mined-out roadway (60) after the mining is completed; The method comprises the following steps: Arranging multiple heading machines (40), wherein the multiple heading machines (40) are arranged at the step distance L, stop after mining a preset distance in the first area to be mined (20), and move to the second area to be mined (30) for mining; Adjusting the working content of the heading machine (40), and selecting one of the multiple heading machines (40) to perform secondary floor recovery to connect multiple mined-out roadways (60) formed by the first area to be mined (20) and the second area to be mined (30) to form multiple mined-out roadways (60); Further comprising temporarily sealing the mined roadway, One end of the mined roadway is provided with a reserved coal seam (50), and the other end of the mined roadway is provided with a sealing member (120) to seal the other end of the mined roadway, so as to avoid the heading machine (40) during secondary floor recovery; and / or One end of the mined roadway is provided with a reserved coal seam (50), and the other end of the mined roadway is provided with a sealing member, which is connected with the mined-out roadway (60) to seal the other end of the mined roadway; Step four: filling the mined-out roadway (60) with the paste (10); Step five: repeating steps three to four until the mining of the coal seam to be mined is completed.

2. The coal extraction method according to claim 1, characterized in that, In step three, the method further comprises embedding a filler pipe (110) in the mined-out roadway (60) before sealing the mined-out roadway (60), and the filler pipe (110) is movably arranged in the mined-out roadway (60).

3. The coal extraction method according to claim 1, characterized in that, The adjustment of the working content of the heading machine (40) further comprises arranging at least one of the multiple heading machines (40) on one of the first area to be mined (20) and the second area to be mined (30), and arranging the remaining heading machines (40) on the other of the first area to be mined (20) and the second area to be mined (30).

4. The coal extraction method according to claim 1, characterized in that, In the heading machine (40), when mining in the first area to be mined (20) or the second area to be mined (30), the heading speed of the heading machine (40) is V1, and the speed of the heading machine (40) when performing secondary floor recovery is V2, wherein V1 is less than V2.

5. The coal extraction method according to claim 1, characterized in that, In step four, filling the mined-out roadway (60) with the paste (10) comprises injecting the paste (10) into the mined-out roadway (60) in stages.

6. The coal extraction method of claim 1, wherein, Step five further comprises recovering the floor and filling the coal seam to be mined.

7. The coal extraction method according to any one of claims 1 to 6, characterized in that, Step three further comprises embedding an exhaust pipe in the mined-out roadway (60).

Images