Displaced pier support self-flowing backfilling mining method

Abstract

This invention belongs to the field of coal mine backfilling mining technology, and relates to a self-flowing backfilling mining method supported by staggered piers. The method includes the following steps: pre-burying backfilling pipelines; preparing and storing backfilling material slurry for later use; pouring transverse and longitudinal concrete retaining walls; pouring multiple concrete piers and a concrete sealing wall; and simultaneously carrying out the backfilling slurry and the mining of the next backfilling section. By setting up transverse and longitudinal concrete retaining walls, concrete sealing walls, and multiple concrete piers at the coal mine working face, this invention creates a sealed environment in the current backfilling section, preventing the backfilling slurry from affecting the mining of the next backfilling section. This allows backfilling and mining to proceed simultaneously, preventing the backfilling of the goaf from affecting normal mining, improving the production efficiency of the working face, ensuring coal production, and simultaneously consuming surface-accumulated gangue, mitigating surface subsidence, and protecting the ecological environment.

Description

Technical Field

[0001] This invention belongs to the field of coal mine backfilling mining technology, and relates to a self-flowing backfilling mining method supported by staggered piers. Background Technology

[0002] After coal is extracted from underground, the overlying strata in the goaf gradually fracture and collapse, easily causing severe surface subsidence, damage to structures, and disruption of groundwater systems. Furthermore, coal mining generates large amounts of solid waste—gangue—which accumulates on the surface to form gangue mountains. The dust from weathered gangue severely impacts air quality in the mining area, and heavy metals contained within it enter groundwater after rain, polluting water resources. Additionally, gangue mountains are prone to spontaneous combustion, releasing harmful gases. The technology of backfilling mining, which injects gangue, fly ash, and other backfill materials into the goaf, aims to support the roof, reduce surface subsidence, and protect the ecological environment.

[0003] However, existing backfilling technology suffers from time and space interference between backfilling and mining. Generally, backfilling preparations need to begin after mining is completed, backfilling begins after preparations are completed, and mining can only resume after the slurry has solidified. The repetitive and complicated cycle and the waiting time after grouting directly prolong the entire mining cycle, resulting in reduced working face production efficiency and affecting coal output. Summary of the Invention

[0004] The purpose of this invention is to provide a self-flowing backfilling mining method supported by staggered piers, which can take into account both backfilling and mining, avoid backfilling affecting normal mining, and improve the production efficiency of the working face.

[0005] To achieve the above objectives, the present invention provides a specific technical solution for a self-flowing backfilling mining method supported by staggered piers, as follows:

[0006] A self-flowing backfilling mining method supported by staggered piers includes the following steps:

[0007] The coal mine working face is divided into multiple filling areas along its advancing direction. Boreholes are drilled at the corresponding surface locations of the multiple filling areas, and each borehole is connected to the corresponding filling area. Filling pipelines are pre-embedded in each borehole.

[0008] The gangue deposited on the ground is prepared into a backfill material slurry;

[0009] A first haulage roadway and a second haulage roadway are set on both sides of the width of the coal mine working face. After the first section of the filling area is mined out, a transverse concrete retaining wall is poured in the first section of the filling area, and a longitudinal concrete retaining wall is poured in the first haulage roadway, so that the transverse concrete retaining wall and the longitudinal concrete retaining wall are connected.

[0010] In the first transport roadway, multiple concrete piers are poured along the direction of the coal mine working face. In the second transport roadway, near the transverse concrete retaining wall, a concrete sealing wall is poured along the width of the coal mine working face, so that the concrete sealing wall is connected to the transverse concrete retaining wall.

[0011] The filling material slurry is injected into the filling pipeline. The filling material slurry flows into the first filling area through the filling pipeline. After the first filling area is filled, the next filling area is mined at the same time. The above steps are repeated to fill each filling area in turn.

[0012] The invention is further characterized by:

[0013] When pouring the transverse concrete retaining wall, a filling support is set up along the width of the coal mine working face at the position of the first filling area close to the second filling area, and a flexible mold filling bag is hung behind the filling support. Then, concrete is injected into the flexible mold filling bag for filling to obtain the transverse concrete retaining wall.

[0014] Each of the concrete piers has a flexible pad at its upper end.

[0015] A steel wire mesh is fixedly installed between two adjacent concrete piers.

[0016] Several of the concrete piers are arranged in two rows, with the two rows of concrete piers staggered.

[0017] The spacing between two adjacent concrete piers in the width direction of the coal mine working face is determined by the following formula:

[0018] .

[0019] Where S is the distance between two adjacent concrete piers in the width direction of the coal mine working face, and d is the diameter of the concrete pier.

[0020] While the filling material slurry is filling the first filling area, a cementing material is injected into the first filling area through the filling pipeline. The cementing material mixes with the filling material slurry to form a filling body to fill the first filling area.

[0021] The self-flowing backfilling mining method supported by staggered piers of the present invention has the following advantages:

[0022] First, by setting up transverse concrete retaining walls, longitudinal concrete retaining walls, concrete sealing walls, and multiple concrete piers at the coal mine working face, a sealed environment can be formed in the current section filling area. This prevents the solidification of the filling material slurry from affecting the mining of the next section filling area, allowing mining and filling to proceed simultaneously. This avoids the filling of the goaf affecting normal mining, improves the production efficiency of the working face, and ensures coal production.

[0023] Secondly, by preparing a filling slurry from gangue, fly ash, cement, and other materials and filling it into the goaf, the slurry solidifies and supports the roof of the goaf, effectively controlling the fracturing and collapse of the overlying rock in the goaf, thereby alleviating the damage to the surface caused by coal mining. At the same time, it can also consume the gangue accumulated on the surface and protect the ecological environment.

[0024] Third, by setting up multiple concrete pillars in a staggered arrangement to support the roadway roof, the first transport roadway is retained as the roadway for the next working face mining, which improves the succession efficiency of working face mining, reduces the amount of coal pillars left, and increases the resource recovery rate of the mining area. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall top view of the coal mine working face in this invention.

[0026] Figure 2 This is a schematic diagram of the overall left-side structure of the coal mine working face according to the present invention.

[0027] Figure 3 This is a schematic diagram of the concrete pier column in this invention.

[0028] Figure label:

[0029] 1. Filling area; 2. First transport tunnel; 3. Second transport tunnel; 4. Transverse concrete retaining wall; 5. Longitudinal concrete retaining wall; 6. Concrete sealed wall; 7. Concrete pier; 8. Reinforcing wire mesh; 9. Filling support; 10. Filling pump station; 11. Mobile pump station; 12. First grouting pipe; 13. Second grouting pipe; 14. Filling pipeline; 15. Flexible cushion layer; 16. Filling body. Detailed Implementation

[0030] The technical solutions of this application will now be described clearly and in detail with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " indicates "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more. The terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0031] like Figure 1 , Figure 2 , Figure 3 As shown, the present invention provides a self-flowing backfilling mining method supported by staggered piers, comprising the following steps:

[0032] The coal mine working face is divided into multiple filling areas 1 along its advancing direction. Boreholes are drilled at the corresponding surface locations of the multiple filling areas 1, and each borehole is connected to the corresponding filling area. A filling pipeline 14 is pre-embedded in each borehole.

[0033] The surface-accumulated gangue is crushed, screened, and ball-milled in sequence, and then mixed with fly ash and cement in a certain proportion to prepare a filling material slurry. The filling material slurry is then stored for later use.

[0034] A first transport roadway 2 and a second transport roadway 3 are respectively set on both sides of the width direction of the coal mine working face. After the mining of the first section of the filling area is completed, a transverse concrete retaining wall 4 is poured along the width direction of the coal mine working face in the first section of the filling area. The transverse concrete retaining wall 4 is located close to the next section of the filling area, that is, the transverse concrete retaining wall 4 is located in the first section of the filling area and is close to the second section of the filling area. A longitudinal concrete retaining wall 5 is poured along the advancing direction of the coal mine working face in the first transport roadway 2 near the first section of the filling area, and the transverse concrete retaining wall 4 is connected to the longitudinal concrete retaining wall 5.

[0035] In the first transport roadway 2, near the longitudinal concrete retaining wall 5, multiple concrete piers 7 are poured along the direction of coal mine face advancement. In the second transport roadway 3, near the transverse concrete retaining wall 4, a concrete sealing wall 6 is poured along the width direction of the coal mine face, so that the concrete sealing wall 6 is connected to the transverse concrete retaining wall 4.

[0036] The stored filling material slurry is injected into the filling pipeline 14. Under the action of gravity, the filling material slurry flows into the first filling area through the filling pipeline 14. The entire first filling area is filled. While filling the first filling area, the next filling area is simultaneously mined. The above steps are repeated to fill each filling area in turn.

[0037] In summary, the filling material slurry is a high-concentration filling slurry. Through the cooperation of transverse concrete retaining walls 4, longitudinal concrete retaining walls 5, concrete sealing walls 6, and multiple concrete piers 7, a sealed environment is formed in this filling area. This prevents the filling material slurry from affecting the mining of the next filling area, allowing mining and filling to proceed simultaneously. This avoids the filling of the goaf affecting normal mining, improves the production efficiency of the working face, and ensures coal production. Simultaneously, the multiple concrete piers 7 serve as roadway support material for the first transport roadway 2, supporting the roof and preserving a roadway along the goaf. Furthermore, the filling material slurry flows freely upon entering the first filling area, allowing for gravity-flow filling, which better adapts to different geological conditions and improves resource recovery.

[0038] like Figure 1 As shown, when pouring the transverse concrete retaining wall 4, a filling support 9 is set up along the width direction of the coal mine working face at the position of the first filling area close to the second filling area, and a flexible mold filling bag is hung behind the filling support 9. Then, concrete is injected into the flexible mold filling bag for filling to obtain the transverse concrete retaining wall. The transverse concrete retaining wall can be quickly poured through the flexible mold filling bag.

[0039] like Figure 1 , Figure 2 As shown, when pouring the transverse concrete retaining wall 4, a filling pump station 10 and a first grouting pipe 12 are set in the first transport tunnel 2. The concrete slurry is injected into the flexible mold filling bag through the first grouting pipe 12 via the filling pump station 10. At the same time, when pouring the longitudinal concrete retaining wall 5 and multiple concrete piers 7, the concrete slurry is transported to them via the filling pump station 10.

[0040] like Figure 2 As shown, each of the concrete piers 7 is provided with a flexible cushion layer 15 at its upper end. The flexible cushion layer 15 is made of wood and has a buffering effect. It can absorb and disperse stress concentration to a certain extent, so as to relieve the pressure on the roof and avoid the roof collapse caused by excessive local stress, and ensure that filling and mining can be carried out normally.

[0041] like Figure 1 , Figure 3As shown, a steel wire mesh 8 is fixedly installed between two adjacent concrete piers 7. The steel wire mesh 8 can prevent the concrete piers 7 from tilting, avoid the top plate from collapsing, and further ensure that filling and backfilling can be carried out normally.

[0042] like Figure 1 As shown, multiple concrete piers 7 are arranged in two rows, with the two rows of concrete piers staggered. This staggered arrangement allows for the adaptation of coal mining areas with complex geological structures and uneven roof pressure. The staggered arrangement can be flexibly adjusted according to actual conditions to better adapt to different geological conditions and maximize the recovery of coal resources.

[0043] like Figure 1 As shown, the spacing between two adjacent concrete piers in the width direction of the coal mine working face is determined by the following formula:

[0044] .

[0045] Where S is the distance between two adjacent concrete piers in the width direction of the coal mine working face, and d is the diameter of the concrete pier.

[0046] Based on field experience, the value of d is generally taken as φ0.8m~φ1m for the pier column. The distance S between two adjacent concrete pier columns in the width direction of the coal mine working face is 0.4m~0.5m, and the distance L between two adjacent concrete pier columns in the width direction of the coal mine working face is 1.1m~1.3m.

[0047] like Figure 2 , Figure 3 As shown, while the filling material slurry is filling the first section of the filling area, a cementitious material is injected into the first section of the filling area through the first grouting pipe 12. After the cementitious material is mixed with the filling material slurry, a filling body 16 is formed to fill the first section of the filling area. The mixing of the cementitious material with the filling material slurry enables the formed filling body 16 to have high strength, which facilitates the support of the filling area after filling, so that the next section of the filling area can be safely and smoothly mined.

[0048] like Figure 1 , Figure 2 As shown, when pouring the concrete sealed wall 6, a mobile pump station 11 and a second grouting pipe 13 are set up in the second transport tunnel 3. The mobile pump station 11 delivers concrete slurry to the designated location through the second grouting pipe 13 to pour the concrete sealed wall 6.

[0049] Working Principle: During coal mining, the coal face is first divided into multiple filling areas 1 along its advancing direction. Holes are drilled near each filling area 1 on the surface, ensuring each hole connects to its corresponding filling area. Filling pipes 14 are pre-embedded in each hole. Then, the surface-accumulated gangue is crushed, screened, and ball-milled, and mixed with fly ash and cement in a specific ratio to prepare a high-concentration filling material slurry. This slurry is then stored for later use. Next, a first transport roadway 2 and a second transport roadway 3 are constructed on both sides of the coal face's width. After the first filling area is mined out, a transverse concrete retaining wall 4 is poured along the width of the coal face near the second filling area. A longitudinal concrete retaining wall 4 is poured along the advancing direction of the coal face near the first transport roadway 2. Concrete retaining wall 5 is constructed, and the transverse concrete retaining wall 4 is connected to the longitudinal concrete retaining wall 5. Then, multiple concrete piers 7 are poured along the coal face advancing direction near the longitudinal concrete retaining wall 5 in the first transport roadway 2. In the second transport roadway 3, concrete sealing wall 6 is poured along the width direction of the coal face near the transverse concrete retaining wall 4, and the concrete sealing wall 6 is connected to the transverse concrete retaining wall 4 and tightly sealed to prevent the filling material slurry from flowing out. Finally, the stored filling material slurry is injected into the filling pipeline 14. Under the action of gravity, the filling material slurry flows into the first filling area through the filling pipeline 14, and the entire first filling area is filled. While filling the first filling area, the next filling area is mined simultaneously. The above steps are repeated to fill each filling area in turn.

[0050] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A misaligned pier support self-flowing fill mining method characterised by, The method comprises the following steps: Divide the coal mining face into multiple filling areas along the advancing direction of the coal mining face, drill holes at positions on the ground surface corresponding to the multiple filling areas, and make each hole communicate with the corresponding filling area, and pre-bury a filling pipeline in each hole; Prepare the gangue accumulated on the ground surface into filling material slurry; Set a first transport roadway and a second transport roadway on both sides of the coal mining face in the width direction, cast a transverse concrete retaining wall in the first filling area after the first filling area is mined, and cast a longitudinal concrete retaining wall in the first transport roadway, so that the transverse concrete retaining wall and the longitudinal concrete retaining wall are connected; Cast multiple concrete piers in the first transport roadway along the advancing direction of the coal mining face, and cast a concrete sealing wall in the second transport roadway near the transverse concrete retaining wall along the width direction of the coal mining face, so that the concrete sealing wall and the transverse concrete retaining wall are connected; Inject the filling material slurry into the filling pipeline, and the filling material slurry flows into the first filling area through the filling pipeline, the first filling area is filled, and the mining of the next filling area is simultaneously performed while the first filling area is filled, the above steps are repeated, and each filling area is sequentially filled; When the transverse concrete retaining wall is cast, set a filling support along the width direction of the coal mining face at a position near the second filling area in the first filling area, perform a hanging operation of a flexible mold filling bag behind the filling support, and then inject concrete into the flexible mold filling bag to fill the transverse concrete retaining wall.

2. The staggered pillar supported, free-flowing fill mining method of claim 1, wherein, The upper end of each concrete pier is provided with a flexible cushion layer.

3. The staggered pillar supported, free-flowing fill mining method of claim 1, wherein, A steel wire mesh is fixedly arranged between two adjacent concrete piers.

4. The staggered pier support, self-flowing fill, open-pit mining method of claim 1, wherein, The multiple concrete piers are arranged in two rows, and the two rows of concrete piers are arranged in a staggered manner.

5. The staggered pier support, self-flowing fill, open-pit mining method of claim 4, wherein, The distance between two adjacent concrete piers in the width direction of the coal mining face is determined according to the following formula: ， Wherein, S is the distance between two adjacent concrete piers in the width direction of the coal mining face, and d is the diameter of the concrete pier.

6. The staggered pier support, self-flowing fill, open-pit mining method of claim 1, wherein, While the filling material slurry fills the first filling area, a cementing material is injected into the first filling area through the filling pipeline, the cementing material is mixed with the filling material slurry to form a filling body to fill the first filling area.

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