A gangue filling mining method for a near-horizontal coal seam undulating working face

Abstract

This invention proposes a method for backfilling mining in near-horizontal coal seam undulating working faces. The mining process includes the following steps: surveying the backfilling roadway to determine its elevation on the coal transport roadway side and its elevation on the gangue transport roadway side; determining the backfilling inlet based on the survey data; setting the backfilling inlet on the side with the maximum elevation between the coal transport roadway and the gangue transport roadway sides as the backfilling inlet, and sealing the backfilling inlet on the other side; determining the coal seam dip angle; filling the backfilling roadway with backfill to achieve a preset dip angle of 6°~8°; and performing gravity-flow backfilling in the backfilling roadway. This method for backfilling mining in near-horizontal coal seam undulating working faces improves operational continuity and has the advantages of high conveying efficiency and high backfilling efficiency.

Description

Technical Field

[0001] This invention relates to the field of coal mining technology, specifically to a method for backfilling mining of gangue in undulating working faces of near-horizontal coal seams. Background Technology

[0002] In coal mining, the integrated mechanized unit compaction backfilling mining technology (continuous mining and backfilling technology) adopts the skip mining interval backfilling method (that is, the odd number of branch roadways are mined first, and the even number of branch roadways are mined after the backfill body is stable). This technology is widely used because it can effectively control roof collapse and surface subsidence.

[0003] In related technologies, the backfilling process has significant drawbacks in undulating working faces of near-horizontal coal seams (coal seam dip angle 3~5°): when the elevation of the coal haulage roadway and the gangue haulage roadway changes due to geological fluctuations, the traditional fixed backfilling location (such as relying solely on backfilling in the gangue haulage roadway) cannot be used for gravity-flow backfilling, which means that the gangue needs to be transported by mechanical power (such as gangue throwers and jetting machines) throughout the process, resulting in problems such as high energy consumption, low efficiency, and poor backfilling continuity. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of the present invention propose a method for backfilling mining of gangue in undulating working faces of near-horizontal coal seams. This method can improve the continuity of operations and has the advantages of high conveying efficiency and high backfilling efficiency.

[0006] A method for backfilling mining of gangue in a near-horizontal coal seam undulating working face according to an embodiment of the present invention includes the following steps:

[0007] The filling roadway was surveyed to determine its elevation on the coal transport roadway side and its elevation on the gangue transport roadway side.

[0008] Based on the survey data of the filling tunnel, the filling inlet of the filling tunnel is determined. The elevation of the filling tunnel on the coal conveying tunnel side is lower than that on the gangue conveying tunnel side. The filling tunnel on the gangue conveying tunnel side is designated as the filling inlet, and the filling tunnel on the coal conveying tunnel side is sealed off.

[0009] Alternatively, the elevation of the filling tunnel on the coal conveying tunnel side is higher than the elevation of the filling tunnel on the gangue conveying tunnel side, the filling tunnel on the coal conveying tunnel side is set as the filling inlet, and the filling tunnel on the gangue conveying tunnel side is blocked.

[0010] Determine the dip angle of the coal seam, and fill the filling roadway with filler so that the dip angle of the coal seam reaches the preset dip angle of 6°~8°;

[0011] The filling tunnel is filled by gravity flow.

[0012] The method for backfilling mining in undulating near-horizontal coal seams according to embodiments of the present invention can dynamically switch the backfilling position based on survey data of the backfilling roadway, adapting to elevation fluctuations at different heights without requiring downtime and equipment redeployment, thus improving operational continuity. It also avoids the use of long-distance mechanical conveying equipment, offsetting the backfilling cost per working face. Furthermore, the use of gravity-fed backfilling reduces reliance on mechanical conveying, resulting in high backfilling efficiency.

[0013] In some embodiments, surveying the filling tunnel further includes: constructing a connecting tunnel along the inclination of the working face on the side adjacent to the filling working face and between two adjacent filling tunnels, the connecting tunnel connecting the filling tunnel and the gangue transport tunnel for gangue transfer and ventilation.

[0014] In some embodiments, determining the filling inlet of the filling tunnel includes selecting either the filling tunnel on one side of the coal conveying tunnel or the filling tunnel on one side of the gangue conveying tunnel as the filling inlet if the difference between the elevation of the coal conveying tunnel and the elevation of the gangue conveying tunnel is greater than or equal to 1m.

[0015] In some embodiments, determining the dip angle of a coal seam further includes: dip angle Where h is the filling height and L is the length of the filling tunnel.

[0016] The filling height is calculated based on the difference between the determined coal seam dip angle and the preset dip angle in the filling roadway.

[0017] In some embodiments, prior to gravity-flow filling of the filling tunnel, the following steps are also included:

[0018] Slurry and gangue are fed into the filling inlet to mix the slurry and gangue to form a slurry-gangue coupled filling body, which is filled from the filling inlet by gravity flow.

[0019] In some embodiments, the filling tunnel on one side of the gangue transport tunnel serves as a filling inlet. A slurry conveying pipeline is laid in the gangue transport tunnel, and the gangue transport belt conveyor is used to transport gangue and slurry for mixing and filling.

[0020] In some embodiments, the filling tunnel on one side of the coal conveying tunnel serves as a filling inlet. Slurry conveying pipelines are laid in the gangue conveying tunnel, pedestrian passage, and coal conveying tunnel. Gangue is transported to the coal conveying tunnel via the gangue conveyor belt and mixed with slurry for filling.

[0021] In some embodiments, during the gangue conveying process, a conveying assembly is provided between the coal conveying belt and the filling inlet to convey the gangue on the coal conveying belt to the filling inlet.

[0022] In some embodiments, the method for backfilling mining of gangue in a near-horizontal coal seam undulating working face according to the present invention further includes the following steps: in the backfilling roadway, the remaining unfilled triangular areas are backfilled using a jetting machine.

[0023] In some embodiments, the working face is monitored for elevation every 50m. Based on the elevation of the filling roadway on the coal transport roadway side and the elevation of the filling roadway on the gangue transport roadway side, the operation is carried out in a cyclical manner. Attached Figure Description

[0024] Figure 1 This is a schematic diagram illustrating the use of a gangue backfilling mining method for near-horizontal coal seam undulating working faces according to an embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram illustrating the use of a method for backfilling mining in a near-horizontal coal seam undulating working face according to another embodiment of the present invention.

[0026] Figure 3 yes Figure 2 An enlarged schematic diagram of A shown in the figure.

[0027] Figure label:

[0028] 1. Coal conveyor roadway; 11. Coal conveyor belt conveyor.

[0029] 2. Waste transport tunnel; 21. Waste transport belt conveyor.

[0030] 3. Filling tunnel,

[0031] 4. Connecting alley,

[0032] 5. Pedestrian walkway

[0033] 6. Grout delivery pipeline,

[0034] 7. Conveying components. Detailed Implementation

[0035] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0036] like Figures 1-3 As shown, the method for backfilling mining of gangue in a near-horizontal coal seam undulating working face according to an embodiment of the present invention includes the following steps:

[0037] A survey was conducted on filling roadway 3 to determine its elevation on the side of coal conveying roadway 1 and on the side of waste rock conveying roadway 2. It is understood that the survey of filling roadway 3 should be conducted using high-precision measuring instruments (such as laser rangefinders and total stations) to record its length and elevation data on both sides of the roadway. This ensures data accuracy and provides a reliable basis for the subsequent selection of the feed inlet for filling roadway 3. It also helps in the timely detection of geological changes, adjustment of filling strategies, and improvement of filling efficiency.

[0038] Based on the survey data of filling roadway 3, the filling inlet of filling roadway 3 is determined. The elevation of filling roadway 3 on the coal conveying roadway 1 side is lower than the elevation of filling roadway 3 on the gangue conveying roadway 2 side. Filling roadway 3 on the gangue conveying roadway 2 side is set as the filling inlet, and filling roadway 3 on the coal conveying roadway 1 side is sealed. Alternatively, the elevation of filling roadway 3 on the coal conveying roadway 1 side is lower than the elevation of filling roadway 3 on the gangue conveying roadway 2 side. Filling roadway 3 on the coal conveying roadway 1 side is set as the filling inlet, and filling roadway 3 on the gangue conveying roadway 2 side is sealed.

[0039] It is understandable that, as the working face advances, depending on the actual working conditions, there will be a height difference between the filling roadway 3 on the side of the coal conveying roadway 1 and the side of the gangue conveying roadway 2. That is, the elevation of the filling roadway 3 on the side of the coal conveying roadway 1 may be lower than the elevation of the filling roadway 3 on the side of the gangue conveying roadway 2, and it is also possible that the elevation of the filling roadway 3 on the side of the coal conveying roadway 1 may be lower than the elevation of the filling roadway 3 on the side of the gangue conveying roadway 2.

[0040] In other words, based on the actual working conditions, since there is a difference in elevation between the filling roadway 3 on the coal conveying roadway 1 side and the filling roadway 3 on the gangue conveying roadway 2 side, a certain slope is formed inside the filling roadway 3. Therefore, it is easier to realize subsequent filling operations by using the side of the filling roadway 3 with a higher slope as the filling inlet.

[0041] Therefore, based on the elevations at both ends of filling tunnel 3, the position of the filling inlet can be dynamically switched, optimizing the inlet position of filling tunnel 3, facilitating subsequent filling operations, and reducing energy consumption. It also improves filling efficiency, reduces the need for mechanical conveying of gangue, and lowers costs.

[0042] Determine the coal seam dip angle and fill the filling roadway 3 with filler material to bring the coal seam dip angle to the preset 6°~8°. Understandably, if the coal seam dip angle does not reach the preset 6°~8° by measurement, filling work needs to be carried out in the filling roadway 3 to ensure that the coal seam dip angle reaches the preset 6°~8° after the filling work is completed.

[0043] In other words, based on actual working conditions, gravity-flow filling is more easily achieved when the dip angle of filling roadway 3 is between 6° and 8°. Therefore, based on the measured dip angle of filling roadway 3, if the dip angle of filling roadway 3 does not meet the preset dip angle, filling roadway 3 needs to be filled. This not only maintains the stability of the coal seam but also provides operational space for subsequent filling.

[0044] Gravity-flow filling is carried out in filling tunnel 3. Understandably, a direct-flow filling process is used, where gangue and other fillers are directly fed into filling tunnel 3 to achieve continuous and efficient filling. This not only improves the continuity of filling and reduces interruptions, but also lowers energy consumption and labor costs during the filling process. Furthermore, it increases the density of the filling material, enhances its stability, and effectively controls roof collapse and surface subsidence.

[0045] In other words, the method for backfilling mining in near-horizontal coal seam undulating working faces according to the embodiments of the present invention can dynamically switch the backfilling position based on the survey data of the backfilling roadway 3, adapting to elevation differences at different heights, without the need for downtime and equipment redeployment, thus improving operational continuity. It also avoids the use of long-distance mechanical conveying equipment, offsetting the backfilling cost per working face. Furthermore, the use of gravity-flow backfilling reduces reliance on mechanical conveying, resulting in high backfilling efficiency.

[0046] In some embodiments, surveying the filling tunnel 3 further includes: opening a connecting tunnel 4 on the side adjacent to the filling working face and between two adjacent filling tunnels 3 along the inclination of the working face, the connecting tunnel 4 connecting the filling tunnel 3 and the gangue transport tunnel 2 for gangue transfer and ventilation.

[0047] It is understandable that, such as Figure 1 As shown, the extension direction of connecting roadway 4 is consistent with the dip direction of the working face. Through connecting roadway 4, gangue can be transported more directly and quickly from gangue haulage roadway 2 to coal haulage roadway 1, reducing transportation distance and time, and lowering transportation costs. The opening of connecting roadway 4 increases the flexibility and adaptability of the working face, enabling the backfilling process to better adapt to site conditions.

[0048] In addition, the opening of connecting lane 4 provides an additional ventilation channel for the working face, which helps to improve the ventilation conditions of the working face, reduce the accumulation of harmful gases, and protect the health and safety of workers.

[0049] Optionally, the connecting roadway 4 can be connected in parallel with the existing return airway at the working face, or a separate ventilation fan can be installed to achieve mechanical ventilation. Preferably, the air velocity is ensured to be greater than or equal to 0.25 m / s to meet the relevant provisions of the coal mine safety regulations.

[0050] In some embodiments, determining the filling inlet of the filling tunnel 3 includes selecting the filling tunnel 3 on one side of the coal conveying tunnel 1 or the filling tunnel 3 on one side of the coal conveying tunnel 2 as the filling inlet if the difference between the elevation of the coal conveying tunnel 1 and the elevation of the gangue conveying tunnel 2 is greater than or equal to 1m.

[0051] Understandably, if the elevation of coal conveying roadway 1 is lower than that of gangue conveying roadway 2, and the difference is greater than or equal to 1 meter, then the filling roadway 3 on one side of coal conveying roadway 1 will be selected as the filling inlet, and the filling roadway 3 on the side of gangue conveying roadway 2 will be sealed.

[0052] If the elevation of the gangue haulage roadway 2 is lower than that of the coal haulage roadway 1, and the difference is greater than or equal to 1 meter, then the filling roadway 3 on one side of the gangue haulage roadway 2 is selected as the filling inlet, and the filling roadway 3 on the one side of the coal haulage roadway 1 is sealed.

[0053] In other words, by selecting the side with the lower elevation as the feed inlet, gravity can be used to achieve automatic flow of gangue, reducing transportation energy consumption and improving filling efficiency. It also reduces reliance on mechanical conveying equipment, lowers machinery usage and maintenance costs during the filling process, reduces mechanical operation, and lowers safety risks during operations.

[0054] In some embodiments, determining the dip angle of a coal seam further includes: dip angle Where h is the filling height and L is the length of filling roadway 3. The filling height is calculated based on the difference between the determined coal seam dip angle and the preset dip angle of filling roadway 3.

[0055] Understandably, based on the survey of filling tunnel 3, corresponding values ​​can be obtained, such as the dip angle, filling height, and length of filling tunnel 3. Generally, as the working face advances, the dip angle of filling tunnel 3 is 3~5°, and the preset dip angle is 6°~8°, that is, the preset dip angle can meet the critical angle for gravity-flow filling (i.e., the dip angle is greater than or equal to 6°).

[0056] Taking a 50m filling tunnel 3 with an original inclination angle of 3~5° as an example, if the preset inclination angle is 6°~8°, then filling material needs to be added to the filling tunnel 3 to increase the inclination angle of the filling tunnel 3 by at least 3°.

[0057] Therefore, based on the length of the filling tunnel being 50m and the formula for calculating the dip angle, if we want to increase the dip angle by 3°, we can deduce the following: , Since the original inclination angle was 3~5°, the calculated total inclination angle was 6.4~8.4°, which, when rounded up, is 6°~8°, satisfying the critical angle for self-flowing filling.

[0058] Therefore, the height of the filling inlet was increased by 3m based on the original coal conveying roadway 1 floor, and filling material was added to the filling roadway 3 to form an inclined surface to facilitate subsequent gravity-flow filling.

[0059] It should be noted that if geological conditions prevent the excavation of a 50m long filling tunnel 3, it can be achieved by shortening the filling tunnel 3 to 30m and increasing its height by 4m (inclination angle). This also meets the requirements for gravity-flow filling. In other words, the ratio of height to tunnel length can be adaptively adjusted according to actual working conditions.

[0060] In some embodiments, before gravity filling of the filling tunnel 3, the method further includes the following steps: conveying slurry and gangue to the filling inlet, mixing the slurry and gangue to form a slurry-gangue coupled filling body, which is gravity-fed from the filling inlet.

[0061] Understandably, pumps and other equipment are used to transport the slurry to the filling inlet, while gangue is transported to the same location via belt conveyors. This ensures that the slurry and gangue are delivered to the filling inlet in a timely and accurate manner, preparing for the mixing and formation of the slurry-gangue coupled filling body.

[0062] At the filling inlet, the delivered slurry is mixed with the gangue to form a uniform slurry-gangue coupled filling body. The slurry can penetrate into the voids between the gangue, increasing the bonding force between them and thus improving the overall stability of the filling body. The slurry fills the voids between the gangue, making the filling body more compact and helping to control surface subsidence.

[0063] In other words, by utilizing the fluidity of the slurry-gangue coupling filling material, it flows into the filling tunnel 3 from the filling inlet in a gravity-flow manner. This reduces the need for mechanical conveying, thereby lowering energy consumption and costs. Gravity-flowing filling can be carried out continuously, improving filling efficiency and reducing downtime during the filling process.

[0064] In some embodiments, the filling tunnel 3 on one side of the gangue transport tunnel 2 serves as the filling feed inlet. A slurry conveying pipeline 6 is laid in the gangue transport tunnel 2, and the gangue transport belt conveyor 21 is used to transport gangue and slurry for mixing and filling.

[0065] It is understandable that, such as Figure 1 As shown, when the filling tunnel 3 on one side of the gangue transport tunnel 2 is used as the filling inlet, the space of the gangue transport tunnel 2 can be used to lay the slurry pipeline 6 to facilitate the transportation of slurry, and the gangue transport belt conveyor 21 can also be used to directly transport gangue.

[0066] In other words, when the filling tunnel 3 on one side of the gangue transport tunnel 2 is used as the filling feed inlet, the overall layout of the working face basically does not need to be modified. The existing space and equipment can be used to realize the transportation of slurry and gangue, reducing the use of additional mechanical equipment and lowering the safety risks in the operation process.

[0067] In other embodiments, such as Figure 2 and Figure 3As shown, the filling tunnel 3 on one side of the coal conveying tunnel 1 serves as the filling inlet. The slurry conveying pipeline 6 is laid in the gangue conveying tunnel 2, the pedestrian passage 5 and the coal conveying tunnel 1. The gangue is transported to the coal conveying belt 11 via the connecting tunnel 4 using the gangue conveying belt 21 and mixed with the slurry for filling.

[0068] It is understandable that, such as Figure 2 and Figure 3 As shown, when the filling roadway 3 on one side of the coal conveying roadway 1 serves as the filling feed inlet, a branch road needs to be led out from the slurry conveying pipeline 6 located in the gangue conveying roadway 2, and arranged to pass through pedestrian access and the coal conveying roadway 1. Furthermore, the gangue from the gangue conveying roadway 2 needs to be horizontally transported to the coal conveying conveyor belt 11 of the coal conveying roadway 1 via the connecting roadway 4, so that the gangue and slurry can be mixed and slurryed at the filling feed inlet on one side of the coal conveying roadway 1 for filling.

[0069] In other words, when the filling roadway 3 on one side of the coal conveying roadway 1 is used as the filling inlet, the working face structure (i.e., it needs to utilize the space of the pedestrian passage 5 and part of the coal conveying roadway 1) needs to be planned and modified in order to complete the transportation and filling of gangue and slurry.

[0070] A belt conveyor can be installed in the connecting roadway 4 to enable the transport of gangue from the gangue transport roadway 2 to the coal transport roadway 1.

[0071] In some embodiments, during the gangue conveying process, a conveying assembly 7 is provided between the coal conveying belt 11 and the filling inlet for conveying the gangue on the coal conveying belt 11 to the filling inlet.

[0072] It is understandable that, such as Figure 2 and Figure 3 As shown, a conveying assembly 7, such as a conveyor belt, conveyor, or conveying pipeline, is installed between the coal conveying conveyor 11 and the filling inlet. After the gangue is unloaded from the coal conveying conveyor 11, it is conveyed to the filling inlet via the conveying assembly 7 (i.e., the gangue needs to be lifted to a certain height).

[0073] In other words, the conveying assembly 7 includes chain conveyors or screw conveyors and employs a closed-loop transport design to transport gangue to higher elevations. The design of the conveying assembly 7 typically considers conveying efficiency and speed, enabling rapid transport of gangue to the filling inlet. This reduces the need for manual handling, lowers labor costs, and improves safety. Furthermore, through precise control of the conveying assembly 7, better uniform distribution of gangue and slurry can be ensured before mixing, thereby improving the quality of the mixed filling material. Precise control of the conveying assembly 7 helps reduce errors during the mixing process, ensuring the stability and density of the filling material.

[0074] Optionally, the conveying assembly 7 also includes a belt cleaning device, i.e., a cleaning device, such as a scraper and a high-pressure air nozzle, is added to the tail of the conveyor to ensure that the gangue is transported without residue.

[0075] In some embodiments, the method for backfilling mining of gangue in a near-horizontal coal seam undulating working face according to the present invention further includes the following steps: in the backfilling roadway 3, the remaining unfilled triangular areas are backfilled using a jetting machine.

[0076] Understandably, during filling of filling tunnel 3, due to its inclined internal structure, gravity-flow filling can easily lead to the formation of triangular areas at the corners of the roof that cannot be filled by gravity flow. Therefore, a jet filling machine is required.

[0077] In other words, the spraying machine can spray filling material into hard-to-reach corners and gaps, improving the integrity and coverage of the filling. The spraying machine fills quickly, rapidly completing the filling of triangular areas, thus improving filling efficiency. Spraying machine filling reduces manual operation, lowering labor costs and labor intensity.

[0078] In some embodiments, the working face is monitored for elevation every 50m. Based on the elevation of the filling roadway 3 on the side of the coal transport roadway 1 and the elevation of the filling roadway 3 on the side of the gangue transport roadway 2, the operation is carried out in a cyclical manner.

[0079] Understandably, if the elevation of coal transport roadway 1 or gangue transport roadway 2 reverses from the previously detected elevation during the working face advance, it is necessary to switch modes and carry out filling operations on the side with higher elevation, thus forming a closed-loop adaptive system of "elevation monitoring - mode switching - efficient filling".

[0080] Therefore, the method for backfilling mining of gangue in undulating working faces of near-horizontal coal seams according to the embodiments of the present invention utilizes gravity-flow backfilling to reduce reliance on mechanical transportation and improve single-shift backfilling efficiency; it eliminates long-distance transmission equipment, reducing the backfilling cost per working face; and by dynamically switching the filling position, it can adapt to elevation fluctuations at different heights without stopping and redeploying equipment, improving operational continuity; the parallel ventilation system keeps the gas concentration at the working face stable below 0.5%, and the closed design of the conveying component 7 reduces the risk of gangue splashing; gravity-flow backfilling combined with slurry-gangue mixing process improves the density of the backfill body, reduces roof subsidence, and can effectively control surface subsidence.

[0081] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0082] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0083] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0084] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0085] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0086] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for backfilling mining of gangue in undulating working faces of near-horizontal coal seams, characterized in that, Includes the following steps: The filling roadway is surveyed to determine the elevation of the filling roadway on the side of the coal transport roadway and the elevation of the filling roadway on the side of the gangue transport roadway. A connecting roadway is opened on the side adjacent to the filling working face and between two adjacent filling roadways along the dip of the working face. The connecting roadway connects the filling roadway and the gangue transport roadway for gangue transfer and ventilation. Based on the survey data of the filling tunnel, the filling inlet of the filling tunnel is determined. The elevation of the filling tunnel on the coal conveying tunnel side is lower than that on the gangue conveying tunnel side. The filling tunnel on the gangue conveying tunnel side is designated as the filling inlet, and the filling tunnel on the coal conveying tunnel side is sealed off. Determining the filling inlet of the filling tunnel includes: the difference between the elevation of the coal conveying tunnel and the elevation of the gangue conveying tunnel is greater than or equal to 1m. Either the filling tunnel on the coal conveying tunnel side or the filling tunnel on the gangue conveying tunnel side is selected as the filling inlet. Alternatively, the elevation of the filling tunnel on the coal conveying tunnel side is higher than the elevation of the filling tunnel on the gangue conveying tunnel side, the filling tunnel on the coal conveying tunnel side is set as the filling inlet, and the filling tunnel on the gangue conveying tunnel side is blocked. The dip angle of the coal seam is determined, and filling material is added to the filling roadway to bring the dip angle of the coal seam to a preset dip angle of 6°~8°. Where h is the filling height and L is the length of the filling tunnel. The filling height is calculated based on the difference between the determined coal seam dip angle and the preset dip angle of the filling tunnel. Slurry and gangue are fed into the filling inlet to mix the slurry and gangue to form a slurry-gangue coupled filling body, which is filled from the filling inlet by gravity flow. The filling tunnel is filled by gravity flow; Every 50m of advance of the working face, the elevation is monitored. Based on the elevation of the filling roadway on the coal transportation roadway side and the elevation of the filling roadway on the gangue transportation roadway side, the operation is carried out in a cyclical manner.

2. The method for backfilling mining of gangue in a near-horizontal coal seam undulating working face according to claim 1, characterized in that, The filling tunnel on one side of the gangue transport tunnel serves as the filling inlet. A slurry conveying pipeline is laid in the gangue transport tunnel, and the gangue transport belt conveyor is used to transport gangue and slurry for mixing and filling.

3. The method for backfilling mining of gangue in a near-horizontal coal seam undulating working face according to claim 2, characterized in that, The filling tunnel on one side of the coal transport tunnel serves as the filling inlet. Slurry pipelines are laid in the gangue transport tunnel, pedestrian passage, and coal transport tunnel. Gangue is transported to the coal transport tunnel via the gangue transport belt conveyor through the connecting tunnel and mixed with slurry for filling.

4. The method for backfilling mining of gangue in a near-horizontal coal seam undulating working face according to claim 3, characterized in that, During the gangue transportation process, a conveying assembly is installed between the coal conveyor belt and the filling inlet to transport the gangue on the coal conveyor belt to the filling inlet.

5. The method for backfilling mining of near-horizontal coal seam undulating working faces according to claim 2 or 3, characterized in that, It also includes the following steps: In the filling tunnel, the remaining unfilled triangular areas are filled using a jet filling machine.

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