A method for drainage and grouting disposal of gangue in the space under the rear cantilever roof of a coal mine.

Abstract

This invention discloses a method for draining and grouting gangue in the space below the suspended roof behind a coal mine support, belonging to the technical field of green coal mining. After raw coal is mined underground, it is transported by conveyor belt to an underground integrated operation chamber for screening, intelligent gangue sorting, crushing, mixing, and grouting. An industrial filling pump injects the prepared gangue slurry into the space formed by coal mining. The gangue slurry is then transported to the vicinity of the hydraulic support and mixed with calcium chloride bead-shaped desiccant. After mixing, the mixture is rapidly injected into a geotextile filling device. This method achieves safe and economical utilization of the collapsed space behind the coal mine support to dispose of gangue slurry. The filling device restricts the displacement of the gangue slurry, helps it to accumulate and form, increases its height, and thus accelerates the drainage speed of the gangue slurry at the bottom. It also reduces the distance between the gangue slurry drainage solidified body and the roof, reducing the impact load on the roof and exhibiting strong drainage capacity, significantly increasing the gangue slurry drainage solidification speed.

Description

Technical Field

[0001] This invention belongs to the fields of green mining in coal mines and solid waste disposal technology, and particularly relates to a method for drainage and grouting disposal of gangue in the space under the suspended roof of a coal mine. Background Technology

[0002] Coal mining produces a large amount of gangue, and the environmental problems caused by gangue accumulation are becoming increasingly prominent. The country is now vigorously promoting the gangue non-sinking model, which uses in-situ backfilling to dispose of gangue. This can reduce the ineffective transportation of gangue, replace production capacity, improve the efficiency of mines, and alleviate environmental pressure.

[0003] The application prospects of underground coal mine gangue grouting and backfilling technology are promising, but the bottlenecks and difficulties restricting its development lie in the lack of a stable and efficient system implementation plan for gangue disposal without shoveling it to the surface. Existing technologies often treat the space behind the caving frame, which is prone to collapse and dynamic development, as the only viable option. Furthermore, the amount of gangue that can be disposed of within this space is unknown, and there is a lack of technological research and verification to achieve gangue disposal within the caving frame space.

[0004] Based on this, the idea of ​​injecting gangue slurry into the large underground spaces of coal mines (the space between the side roadways and the suspended roof space behind the fully mechanized hydraulic supports) is proposed. These spaces have a relatively fixed capacity and enormous potential for absorption. Currently, without any additives, gangue slurry flows freely, spreading over long distances and making it difficult to accumulate. This poses a high risk, especially in the suspended roof space behind the supports where collapses are possible at any time. Furthermore, gangue slurry retains a certain degree of fluidity throughout the day, remaining in a slurry state. If the roof collapses and impacts the gangue slurry, the slurry itself cannot absorb the enormous kinetic energy of the overburden collapse. After being compressed, it is easily pushed into the fully mechanized hydraulic supports, causing a safety accident.

[0005] How to prevent large-scale displacement of gangue slurry under overburden loads that could collapse at any time, so as to avoid affecting hydraulic supports and the internal structure, has become the primary goal of coal mine production safety. This goal can be achieved by accelerating the drainage or quick-setting of gangue slurry. The purpose of backfilling gangue is to prevent it from being brought to the surface, rather than to control surface subsidence. Adding quick-setting agents to gangue slurry is similar to backfilling mining, which is too costly and slow, making it difficult to implement.

[0006] Against this backdrop, a method for drainage and grouting disposal of gangue in the space below the suspended roof of a coal mine is proposed, providing a new approach for the filling and disposal of coal mine gangue and alleviating the environmental crisis of gangue as a major industrial solid waste. Summary of the Invention

[0007] In view of the above situation and to overcome the defects of the prior art, the present invention provides a method for drainage and grouting disposal of gangue in the space under the rear cantilever roof of a coal mine, which at least partially solves the above-mentioned technical problems.

[0008] The technical solution adopted in this invention is as follows: A method for drainage and grouting disposal of gangue in the space below the rear cantilever roof of a coal mine, comprising the following steps:

[0009] (1) After the raw coal is mined underground, it is transported to the underground screening-intelligent gangue sorting-crushing-mixing-grouting integrated operation chamber by a transfer belt. Then, the prepared gangue slurry is injected into the space formed by coal mining by an industrial filling pump.

[0010] (2) The gangue slurry is transported to the vicinity of the fully mechanized hydraulic support (near the slurry outlet) and mixed with calcium chloride bead-shaped desiccant. After mixing, it is quickly injected into the suspended space behind the support. After the desiccant is mixed with the gangue slurry, it is directly injected into the space behind the support. The desiccant will gradually absorb the water in the gangue slurry and play a certain role in water fixation.

[0011] (3) A large geotechnical filling device is added in the suspended space behind the frame to restrict the flow of mixed gangue slurry. The mixed gangue slurry is directly injected into the filling device, and drainage and consolidation are accelerated on the basis of the gangue material and desiccant.

[0012] In step 1, the gangue sorted by the intelligent gangue sorting machine is crushed using a high-fineness crusher. Smaller average particle size of the crushed gangue is more conducive to long-distance pipeline transportation but less conducive to drainage; conversely, larger average particle size is more conducive to drainage but less conducive to long-distance pipeline transportation. Since the main disposal space is the space under the large suspended roof behind the support structure and the side roadways, the fluidity requirement for the gangue slurry is relatively low. Therefore, in the proportioning of gangue raw materials, based on achieving long-distance transportation, the average particle size of the gangue is increased as much as possible. The proportioning range is as follows: gangue mass concentration above 75% (mass concentration = gangue solid mass / (total mass of gangue + water)), where the content of powder smaller than 0.075mm in the gangue gradation is less than 5%, and the maximum particle size of the gangue gradation should not exceed 5mm. This proportion is achieved by adjusting and selecting appropriate crushing and screening equipment.

[0013] In step 2, the gangue slurry and calcium chloride spherical desiccant are mixed using a pipeline solid-liquid mixer. This mixer is generally small in volume, with the same diameter as the gangue grouting pipeline. The calcium chloride spherical desiccant is conveyed to the corner of the roadway and the hydraulic support by a screw conveyor or pneumatic conveyor. Since the amount of calcium chloride spherical desiccant in the dryer is small and the spherical particles can be conveyed through the pipeline, the conveying equipment and the quantitative feeder used are small in volume, which can meet the production needs without occupying space in the roadway. The mixer and the quantitative feeder above need to be fixed on a movable platform to facilitate synchronous movement with the fully mechanized hydraulic support. This technology can be easily achieved by a mobile, telescopic conveyor.

[0014] Further, in step 3, the filling device includes a filling bag and a plastic drainage board. The plastic drainage board is laid on the roadway floor. Multiple sets of plastic drainage boards are provided, and these sets are connected in sections to enhance the drainage capacity of the mixed gangue slurry at the bottom. Water in the mixed gangue slurry flows into the plastic drainage board through the filling bag, which is placed on the plastic drainage board. A drainage pipe is pre-embedded within the plastic drainage board. Both the plastic drainage board and the pre-embedded drainage pipe are connected in sections to adapt to the continuous movement of the fully mechanized hydraulic support. To prevent water discharged from the gangue slurry from accumulating near the fully mechanized hydraulic support, [the following is implied:] ... Pre-embedded drainage pipes are used to ensure that the water discharged from the plastic drainage pipes and bottom plastic drainage boards near the hydraulic support face of the fully mechanized mining can flow smoothly to the collapsed goaf behind the support, and then flow to the drainage roadway at the bottom of the working face. Multiple sets of plastic drainage pipes for drainage are laid inside the filling bag. A layer of plastic drainage board is laid at the bottom of the filling bag. In conjunction with the plastic drainage pipes laid inside the filling bag, the mixed gangue slurry is directly injected into the filling bag. Based on the action of gangue material and desiccant, drainage and consolidation are accelerated. The plastic drainage board, pre-embedded drainage pipes, plastic drainage pipes and filling bags are all installed, spliced ​​or stretched as the hydraulic support moves continuously.

[0015] Furthermore, the filling bag is provided with a fixing structure at the corners and the middle of the long side. The fixing structure of the filling bag is equipped with a support rod. The fixing structure can be a hook, a binding structure, etc. As the fully mechanized hydraulic support moves, three small holes for installing the filling bag support rods are drilled in parallel according to the designed filling bag position to support the filling bag. After drilling, the filling bag support rods are connected to the filling bag, and the filling bag support rods are inserted into the drilled holes to temporarily fix the filling bag.

[0016] The filling bags are made of 50-200 mesh nylon screen, which is lightweight, low-cost, high-strength, and provides good drainage. Since the amount of gangue filled in the bags after the support is large, the bags also need to be large in volume. However, the internal space of the fully mechanized hydraulic support is relatively small. Therefore, the filling bags made of lightweight, high-strength nylon screen have a very small folded volume, which is a necessary prerequisite for post-support construction and large-volume filling of the fully mechanized hydraulic support. The filling bag volume can reach 2000m³. 3 Furthermore, after the high-strength nylon mesh filling bag is filled with gangue slurry, it serves to drain water but not material, thereby achieving drainage and consolidation.

[0017] Furthermore, the filling bag has an opening structure that matches the plastic drain pipe. This opening structure can be fixed to the plastic drain pipe by means of hooks, binding, buckles, etc.

[0018] The filling bag has a grouting interface near the hydraulic support of the fully mechanized mining unit, which will be connected to a rubber grouting pipe during subsequent construction.

[0019] The plastic drainage pipe is wrapped with geotextile filter cloth. The mixed gangue slurry gradually seeps into the plastic drainage pipe. The geotextile filter cloth prevents gangue particles from clogging the pores of the plastic drainage pipe. Based on the results of indoor research, the arrangement spacing and size of the plastic drainage pipe are designed.

[0020] The beneficial effects of the present invention after adopting the above structure are as follows:

[0021] (1) It has achieved safe and economical utilization of the collapse space behind the coal mine mining frame to dispose of gangue slurry.

[0022] (2) The filling bag restricts the displacement of the gangue slurry, helps it to accumulate and form, increases its height, thereby accelerating the drainage speed of the bottom gangue slurry, reducing the distance between the gangue slurry drainage solid and the top plate, and reducing the impact load on the top plate.

[0023] (3) The construction of the filling bag support rod is simple, which solves the problem of not being able to anchor the construction on the top of the frame, and also avoids the problem that the filling bag cannot exert its filling capacity due to the pressure of the mixed gangue slurry on the filling bag.

[0024] (4) The plastic drainage board, pre-embedded drainage pipe, plastic manifold, drainage pipe and filling bag are all installed, spliced ​​or stretched as the hydraulic support moves continuously. Synchronous movement is achieved.

[0025] (5) A plastic drainage board and a U-shaped drainage pipe are added to the bottom to avoid the problem of water accumulation on the side of the hydraulic support of the fully mechanized mining.

[0026] (6) The plastic collection and drainage pipes added at certain design intervals inside the filling bag can give full play to their drainage capacity and greatly increase the drainage and consolidation speed of gangue slurry. Attached Figure Description

[0027] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0028] Figure 1 This is a cross-sectional schematic diagram of a method for draining and grouting gangue in the space below the rear cantilever roof of a coal mine, as proposed in this invention.

[0029] Figure 2 This is a schematic diagram of the width direction of the fully mechanized mining face for a method of draining and grouting gangue in the space below the rear suspended roof of a coal mine, as proposed in this invention.

[0030] Figure 3 for Figure 2 A magnified view of a portion of the image;

[0031] Figure 4 This is a schematic diagram of the filling device proposed in this invention.

[0032] In the attached diagram: 1. Filler bag, 2. Plastic drainage board, 3. Drainage pipe, 4. Plastic drainage pipe, 5. Grouting interface, 6. Support rod. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0035] like Figures 1-4 As shown, a method for drainage and grouting disposal of gangue in the space below the rear cantilever roof of a coal mine includes the following steps:

[0036] (1) After the raw coal is mined underground, it is transported to the underground screening-intelligent gangue sorting-crushing-mixing-grouting integrated operation chamber by a transfer belt. Then, the prepared gangue slurry is injected into the space formed by coal mining by an industrial filling pump.

[0037] (2) The gangue slurry is transported to the vicinity of the fully mechanized hydraulic support (near the slurry outlet) and mixed with calcium chloride bead-shaped desiccant. After mixing, it is quickly injected into the suspended space behind the support. After the desiccant is mixed with the gangue slurry, it is directly injected into the space behind the support. The desiccant will gradually absorb the water in the gangue slurry and play a certain role in water fixation.

[0038] (3) The gangue slurry after mixing with desiccant still has a certain fluidity and cannot be quickly accumulated in the suspended space behind the frame. This causes the gangue slurry to flow to the vicinity of the hydraulic support, which in turn affects normal production. Therefore, a large geotechnical filling device is added in the suspended space behind the frame to restrict the flow of the mixed gangue slurry. The mixed gangue slurry is directly injected into the filling device, which accelerates drainage and consolidation based on the action of gangue material and desiccant.

[0039] In step 1, the gangue sorted by the intelligent gangue sorting machine is crushed using a high-fineness crusher. Smaller average particle size of the crushed gangue is more conducive to long-distance pipeline transportation but less conducive to drainage; conversely, larger average particle size is more conducive to drainage but less conducive to long-distance pipeline transportation. Since the main disposal space is the space under the large suspended roof behind the support structure and the side roadways, the fluidity requirement for the gangue slurry is relatively low. Therefore, in the proportioning of gangue raw materials, based on achieving long-distance transportation, the average particle size of the gangue is increased as much as possible. The proportioning range is as follows: gangue mass concentration above 75% (mass concentration = gangue solid mass / (total mass of gangue + water)), where the content of powder smaller than 0.075mm in the gangue gradation is less than 5%, and the maximum particle size of the gangue gradation should not exceed 5mm. This proportion is achieved by adjusting and selecting appropriate crushing and screening equipment.

[0040] In step 2, the gangue slurry and calcium chloride spherical desiccant are mixed using a pipeline solid-liquid mixer. This mixer is generally small in volume, with the same diameter as the gangue grouting pipeline. The calcium chloride spherical desiccant is conveyed to the corner of the roadway and the hydraulic support by a screw conveyor or pneumatic conveyor. Since the amount of calcium chloride spherical desiccant in the dryer is small and the spherical particles can be conveyed through the pipeline, the conveying equipment and the quantitative feeder used are small in volume, which can meet the production needs without occupying space in the roadway. The mixer and the quantitative feeder above need to be fixed on a movable platform to facilitate synchronous movement with the fully mechanized hydraulic support. This technology can be easily achieved by a mobile, telescopic conveyor.

[0041] In step 3, the filling device includes a filling bag 1 and a plastic drainage board 2. The plastic drainage board 2 is laid on the roadway floor. Multiple sets of plastic drainage boards 2 are connected in sections to enhance the drainage capacity of the mixed gangue slurry at the bottom. Water in the mixed gangue slurry flows into the plastic drainage board 2 through the filling bag 1, which is placed on the plastic drainage board 2. A drainage pipe 3 is pre-embedded inside the plastic drainage board 2. Both the plastic drainage board 2 and the pre-embedded drainage pipe 3 are connected in sections to adapt to the continuous movement of the fully mechanized hydraulic support. To prevent water discharged from the gangue slurry from accumulating near the fully mechanized hydraulic support, a drainage system is used to prevent water from accumulating near the fully mechanized hydraulic support. Pre-embedded drainage pipes 3 ensure that the water discharged from the plastic drainage pipes 4 and bottom plastic drainage boards 2 near the hydraulic support face flows smoothly to the collapsed goaf behind the support, and then flows to the drainage roadway at the bottom of the working face. Multiple sets of plastic drainage pipes 4 for drainage are laid inside the filling bag 1. A layer of plastic drainage board 2 is laid at the bottom of the filling bag 1. In conjunction with the plastic drainage pipes 4 laid inside the filling bag 1, the mixed gangue slurry is directly injected into the filling bag 1. Based on the action of gangue material and desiccant, drainage and consolidation are accelerated. The plastic drainage board 2, pre-embedded drainage pipes 3, plastic drainage pipes 4 and filling bag 1 are all installed, spliced ​​or stretched as the hydraulic support moves continuously.

[0042] The filling bag 1 is provided with a fixing structure at the corners and the middle of the long side. The fixing structure of the filling bag 1 is equipped with a support rod 6. The fixing structure can be a hook, a binding structure, etc. As the fully mechanized hydraulic support moves, three small holes for installing the support rod 6 of the filling bag 1 are drilled in parallel according to the designed position of the filling bag 1 to support the filling bag 1. After drilling the holes, the support rod 6 of the filling bag 1 is connected to the filling bag 1, and the support rod 6 of the filling bag 1 is inserted into the drilled holes to temporarily fix the filling bag 1.

[0043] The filling bag 1 uses a 50-200 mesh nylon screen, which is lightweight, low-cost, high-strength, and has good drainage. Since the amount of gangue filled in the filling bag 1 after the support is large, the volume of the filling bag 1 also needs to be large. However, the internal space of the fully mechanized hydraulic support is relatively small. At this time, the filling bag 1, which is made of lightweight, high-strength nylon screen, has a very small volume after folding. This is a necessary prerequisite for the construction and large-volume filling after the fully mechanized hydraulic support is erected. The volume of the filling bag 1 can reach more than 2000m3. Moreover, after the gangue slurry is injected into the filling bag 1 made of high-strength nylon screen, it plays the role of draining water but not material, thereby achieving drainage and consolidation.

[0044] The filling bag 1 has an opening structure that matches the plastic drain pipe 4. This opening structure can be fixed to the plastic drain pipe 4 by means of hooks, binding, buckles, etc.

[0045] The filling bag 1 has a grouting interface 5 near the hydraulic support of the fully mechanized mining unit, which will be connected to a rubber grouting pipe during subsequent construction.

[0046] The plastic drainage pipe 4 is wrapped with geotextile filter cloth. The mixed gangue slurry gradually penetrates into the plastic drainage pipe 4. The geotextile filter cloth plays a role in preventing gangue particles from clogging the pores of the plastic drainage pipe 4. Based on the results of indoor research, the arrangement spacing and size of the plastic drainage pipe 4 are designed.

[0047] The specific implementation method is as follows:

[0048] During coal mining, the fully mechanized hydraulic supports continuously move forward. The mixed gangue slurry remains fluid, and the large space below the overhead roof behind the supports allows the slurry to flow freely without accumulation. If not restrained, it will flow towards the working face, affecting normal production. Furthermore, drainage is poor in this condition, making it difficult to quickly drain water from the slurry. Additionally, the slurry cannot accumulate well, resulting in a low accumulation height and a significant distance from the roof, leading to a greater impact from roof loads. Therefore, this paper proposes using a filling bag to restrain the mixed gangue slurry while simultaneously increasing drainage speed and raising the height of the consolidated gangue slurry drainage body, indirectly reducing the roof impact load and thus enabling the safe utilization of this space.

[0049] Install the filling bag:

[0050] Although the suspended roof space behind the coal mine support has a certain periodic collapse characteristic, there is still a risk of collapse, and workers are prohibited from entering, especially in coal seams with high mining heights. Drilling holes for anchoring on the suspended roof behind the support is too dangerous and not feasible. The mass of the filling bag 1 and the plastic drainage pipe 4 is relatively small, and the requirements for the support rod 6 of the filling bag 1 are low. The filling bag 1 does not need to be tightened. It is only set up to prevent the filling bag 1 from being folded by gangue slurry during grouting, which would prevent the filling bag 1 from being fully utilized. As the fully mechanized hydraulic support moves, three small holes are drilled side by side according to the designed position of the filling bag 1 to install the support rod 6 of the filling bag 1, so as to support the filling bag 1. After drilling, the support rod 6 of the filling bag 1 is connected to the filling bag 1, and the support rod 6 of the filling bag 1 is inserted into the drill hole to temporarily fix the filling bag 1.

[0051] The filling bag 1 is laid on top of the plastic drainage board 2 and the pre-embedded drainage pipe 3, and the plastic drainage pipe 4 is installed in the pre-set hole of the plastic drainage pipe 4 in the filling bag 1 at the same time. The plastic drainage pipe 4 is also connected in sections to adapt to the working conditions of continuous movement of the fully mechanized hydraulic support.

[0052] The filling bag 1 itself is made of nylon mesh material, which has good stretching and folding ability. During the continuous movement of the fully mechanized hydraulic support, the filling bag 1 can be stretched synchronously with it.

[0053] The plastic drainage board 2, the pre-embedded drainage pipe 3, the plastic drainage pipe 4, and the filling bag 1 are all installed, spliced, or stretched as the hydraulic support moves continuously.

[0054] When the fully mechanized hydraulic support is advanced to the designed fixed position of the filling bag 1, three small holes that are adapted to the support rod 6 of the filling bag 1 are drilled in parallel to connect the support rod 6 of the filling bag 1 and the filling bag 1. At the same time, the grouting interface 5 of the filling bag 1 is connected to the grouting hose.

[0055] Gangue grouting:

[0056] The internal operating space of the fully mechanized hydraulic support is small, and it does not have the conditions for mixing gangue slurry with calcium chloride spherical desiccant. A pipeline solid-liquid mixer is used. The volume of this mixer is generally small, consistent with the diameter of the gangue grouting pipeline. The calcium chloride spherical desiccant is conveyed to the corner of the roadway and the hydraulic support by a screw conveyor or pneumatic conveyor. Since the amount of calcium chloride spherical desiccant in the dryer is small, and the spherical particles can be conveyed by pipeline, the conveying equipment and the quantitative feeder used are small in size. This can meet the production needs without occupying space in the roadway. The mixer and the quantitative feeder above need to be fixed on a movable platform to facilitate synchronous movement with the fully mechanized hydraulic support. This technology can be easily achieved by a mobile, telescopic conveyor.

[0057] When the fully mechanized hydraulic support and the filling bag 1 reach the designed safe distance, the mixed gangue slurry is filled. The optimal graded gangue is pumped to the vicinity of the fully mechanized hydraulic support by an industrial filling pump. The calcium chloride bead-shaped desiccant can be conveyed to the vicinity of the fully mechanized hydraulic support by pneumatic or screw conveyor. Here, it is mixed by a solid-liquid mixer. After mixing, it is injected into the filling bag 1 through the grouting hose and the grouting structure of the filling bag 1.

[0058] Relying solely on the limiting method, when the mixed gangue slurry level is low, the tensile force on the filling bag 1 is relatively small and can still be supported. However, as the grouting progresses and the height of the mixed gangue slurry increases, the weight and tension of the gangue slurry on the filling bag 1 become increasingly greater, making it prone to rupture. This leads to the mixed gangue slurry overflowing everywhere and even flowing into the coal mining face. At this point, the desiccant mixed in gradually absorbs water inside the filling bag 1, causing the gangue slurry to quickly lose its fluidity. This reduces the tension on the filling bag 1 caused by the increased height of the mixed gangue slurry accumulation, ensuring that it is not damaged.

[0059] The water-absorbing agent and gangue slurry are mixed for a short time, retaining a certain degree of fluidity. The mixed gangue slurry flows within filling bag 1, stopping at the boundary of bag 1 and gradually accumulating upwards. During accumulation, the water-absorbing agent gradually absorbs water from the gangue slurry, while excess water is gradually discharged through the bottom drainage plate and the pre-embedded drainage pipe in the middle. As the accumulation height increases, deformation increases the load, further accelerating the drainage of water from the gangue slurry. Furthermore, the increased accumulation height reduces the distance between the gangue slurry drainage and solidification body and the uncollapsed roof slab, thus reducing the impact force on the roof slab.

[0060] Water discharged from the direction near the goaf flows directly into the goaf, passes through the goaf, and is discharged into the drainage roadway at the bottom of the working face. Water discharged from the direction near the hydraulic support of the fully mechanized mining flows into the goaf through the pre-set drainage pipe 3 below the filling bag 1 and then continues to flow into the drainage roadway.

[0061] In summary, by optimizing the raw material gradation, adding desiccants, and enhancing the drainage capacity of the mixed gangue slurry, rapid drainage and consolidation of gangue slurry were achieved, thereby enabling low-cost and safe utilization of the overhead space behind the coal mine mining frame.

[0062] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents. In conclusion, if those skilled in the art, inspired by this description, design similar structural methods and embodiments without departing from the inventive spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A method for drainage and grouting disposal of gangue in the space below the rear cantilever roof of a coal mine, comprising the following steps: (1) After the raw coal is mined underground, it is transported to the underground screening-intelligent gangue sorting-crushing-mixing-grouting integrated operation chamber by a transfer belt. Then, the prepared gangue slurry is injected into the space formed by coal mining by an industrial filling pump. (2) The gangue slurry is transported to the vicinity of the fully mechanized hydraulic support and mixed with calcium chloride bead-shaped desiccant; (3) A geotechnical filling device is added in the space behind the frame to restrict the flow of mixed gangue slurry, and the mixed gangue slurry is directly injected into the filling device; in, In step 1, the gangue sorted by the intelligent gangue sorting machine is crushed by a fine crushing device. The proportion range of the gangue raw materials is as follows: gangue mass concentration of 75% or more (mass concentration = gangue solid mass / (total mass of gangue + water)), wherein the content of powder smaller than 0.075mm in the gangue gradation is less than 5%, and the maximum particle size of the gangue gradation should not be greater than 5mm; In step 2, the gangue slurry and calcium chloride bead-shaped desiccant are mixed using a pipeline solid-liquid mixer; In step 3, the filling device includes a filling bag and a plastic drainage board. The plastic drainage board is laid on the roadway floor and there are multiple sets of plastic drainage boards connected in sections. The filling bag is placed on the plastic drainage board and a drainage pipe is pre-embedded in the plastic drainage board. Both the plastic drainage board and the pre-embedded drainage pipe are connected in sections to adapt to the continuous movement of the fully mechanized hydraulic support. Multiple sets of plastic drainage pipes for drainage are laid inside the filling bag.

2. The method for drainage and grouting disposal of gangue in the space below the rear cantilever roof of a coal mine according to claim 1, characterized in that, The filling bag is provided with a fixing structure at the corners and the middle of the long side, and a support rod is installed inside the fixing structure of the filling bag.

3. The method for drainage and grouting disposal of gangue in the space below the rear cantilever roof of a coal mine according to claim 1, characterized in that, The filling bag uses a 50-200 mesh nylon screen.

4. The method for drainage and grouting disposal of gangue in the space below the rear cantilever roof of a coal mine according to claim 1, characterized in that, The filling bag has an opening structure that matches the plastic drain pipe.

5. The method for drainage and grouting disposal of gangue in the space below the rear cantilever roof of a coal mine according to claim 1, characterized in that, The filling bag has a grouting interface near the hydraulic support of the fully mechanized mining unit, which will be connected to a rubber grouting pipe during subsequent construction.

6. The method for drainage and grouting disposal of gangue in the space below the rear cantilever roof of a coal mine according to claim 1, characterized in that, The plastic drainage pipe is wrapped with geotextile filter cloth.

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