A negative carbon same-face filling system layout and mining method

Abstract

The present invention discloses a negative carbon same-face filling system layout and mining method, the steps comprising: adopting the back-frame gangue high-porosity filling mining technology for mining, utilizing the goaf-side lane retaining technology to retain the mining lane on one side of the filling section, and utilizing lane side support bodies for reinforcement, to serve as the CO2 injection lane of the current working face and the mining lane on one side of the adjacent filling working face; when the working face advances 300 to 500 meters, utilizing a closed wall to isolate the working face from the rear goaf to form a closed storage space; then arranging boreholes into the goaf through the CO2 injection lane, arranging CO2 injection pipelines in the mining lane and the boreholes; injecting CO2 into the goaf through the CO2 injection pipeline by a CO2 injection pump, and after the injection is completed, starting the injection of CO2 into the next closed space until the working face is fully filled. The system of the present invention has a simple layout, CO2 injection and coal mining filling do not interfere with each other, the operation is flexible, and the sealing space is well sealed, achieving the dual purposes of solid waste disposal and CO2 storage, and realizing green mining of coal resources.

Description

Technical Field

[0001] The present invention belongs to the field of backfill mining, goaf-side tunneling technology and carbon neutrality, and specifically relates to a negative carbon same-face backfill system layout and mining method. Background Art

[0002] Backfill mining technology offers significant technical advantages in controlling surface subsidence, protecting the ecological environment, and disposing and utilizing solid waste from mines. It can address challenges such as surface subsidence, groundwater loss, gas emissions, and land occupation damage at the source of coal resource extraction. Carbon sequestration involves permanently storing CO2 underground or elsewhere to prevent its release into the atmosphere. Therefore, by constructing a confined space within the goaf and sealing CO2 in backfill materials composed primarily of solid wastes such as gangue and fly ash, the dual goals of large-scale solid waste disposal and CO2 sequestration can be achieved.

[0003] Based on this, the present invention proposes a negative carbon same-face filling system layout and mining method, which shows that the system layout is simple, the injection and coal mining filling do not interfere with each other, the CO2 storage space has good sealing, and can realize rapid, efficient and high-porosity filling of underground gangue and large-scale storage of CO2, thereby improving the efficiency and benefits of filling mining, and has broad application prospects. Summary of the Invention

[0004] Purpose of the invention: In response to the deficiencies in the prior art, the present invention provides a negative carbon same-surface filling system layout and mining method. The system has a simple layout, CO2 injection and coal mining filling do not interfere with each other, has a wide range of applications, achieves the dual purposes of solid waste disposal and coordinated CO2 storage, and realizes green mining of coal resources.

[0005] To achieve the above objectives, the present invention provides a negative carbon same-surface filling system arrangement and mining method, comprising the following steps:

[0006] (1) Excavate the return air uphill and transport uphill in one block, then excavate the CT301 transport level tunnel, CT301 return air level tunnel and open the cut hole to form a complete production system;

[0007] (2) CT301 adopts the high-porosity filling mining technology with waste rock behind the frame for mining, and uses the gob-side roadway retention technology to retain the CT301 return air level roadway, and adopts the roadway side support body to reinforce it, which serves as the CO2 injection roadway of this working face and the transportation level roadway of CT302;

[0008] (3) When the CT301 working face advances 300-500 meters, a closed wall is used to separate the working face from the goaf behind it, forming a closed CO2 storage space;

[0009] (4) Drill holes are laid out in the CT301 goaf through the CO2 injection tunnel, and CO2 injection pipelines are arranged in the mining tunnel and the drill holes;

[0010] (5) The CO2 injection pump injects CO2 into the goaf through the CO2 filling pipeline. After the filling is completed, the CO2 injection into the next confined space is started until the working face is filled.

[0011] Preferably, the sealed wall is made of fly ash, cement and gangue, with a thickness of 5 to 10 m, which can effectively isolate the coal mining face from the rear goaf and prevent the filling from affecting the production of the working face.

[0012] Preferably, the enclosed CO2 storage space is composed of enclosed walls, coal pillars, roadway support bodies and high-porosity gangue materials, and the enclosed space formed can effectively prevent the leakage of CO2.

[0013] Preferably, the borehole spacing is greater than 300m, and one borehole is arranged in each enclosed CO2 storage space, located in the middle of the enclosed space. This arrangement of boreholes facilitates the diffusion of CO2 and improves the efficiency of CO2 injection.

[0014] Preferably, the CO2 injection pump is arranged in the chamber for transporting CO2 up the mountain. This arrangement can reduce the length of the CO2 injection pipeline, reduce costs, and improve the CO2 injection efficiency; the injection pump pressure is greater than 7.5MPa. At this pressure, CO2 can reach a supercritical state underground, with high diffusivity, low viscosity and high solubility.

[0015] Preferably, a flow sensor arranged in the CO2 filling pipeline is used to determine whether the filling is completed. When the CO2 injection flow rate in the flow sensor remains unchanged, it can be determined that the CO2 filling is completed.

[0016] Preferably, the order of CT301 CO2 injection and CT301 filling mining is: after CT301 is advanced to a certain distance, a closed wall is laid to form a closed space, the switch valve (13) of pipeline ① (8) is opened to inject CO2, and after the injection is completed, the switch valve (13) of pipeline ① (8) is closed, and CO2 is injected into the next closed space until the working face is filled and the CO2 injection pump is turned off.

[0017] Beneficial effects: The negative carbon same-surface filling system arrangement and mining method provided by the present invention has the following advantages over the prior art:

[0018] 1. Using gangue solid waste as filling material can realize the large-scale disposal and utilization of gangue solid waste, which is economical, green and environmentally friendly;

[0019] 2. The use of high-porosity gangue filling materials increases the porosity of the filling materials, facilitates the migration and diffusion of CO2, and improves the CO2 storage efficiency;

[0020] 3. Use closed walls to isolate the working face from the filling space, so that CO2 filling and coal filling do not interfere with each other;

[0021] 4. The use of side support bodies to reinforce the goaf-side tunnels solves the problems of difficult maintenance of goaf-side tunnels and poor sealing of CO2 storage space. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a working face layout diagram of a negative carbon same-face filling system layout and mining method of the present invention;

[0023] In the figure: 1—return air uphill; 2—transport uphill; 3—stop mining line; 4—CT301 transport level tunnel; 5—CT301 return air level tunnel; 6—CO2 injection pump; 7—CO2 filling pipeline; 8—Pipeline ①; 9—Pipeline ②; 10—sealed wall; 11—Pipeline switch valve; 12—tunnel side support body; 13—coal pillar; 14—high-porosity gangue filling material; 15—flow sensor. DETAILED DESCRIPTION

[0024] The following describes in detail the arrangement of the negative carbon same-surface filling system and the mining method of the present invention in conjunction with the accompanying drawings.

[0025] Taking the No. 3 mining area of ​​a certain mine as an example, CT301 is currently being mined. The coal seam is buried at a depth of -750 to -1000m, with an average thickness of 3.8m and an average dip of 6°. The roof of the coal seam is composed of sandy mudstone, muddy siltstone, and mudstone, and the old roof is often composed of medium- and fine-grained sandstone; the floor is generally composed of mudstone, sandy mudstone, and siltstone. The working face is 200m long and the advance length is 1000m. Figure 1 As shown, the dotted line is the stop mining line (3), and the negative carbon same-face filling mining process is as follows:

[0026] S1, excavate the return air uphill (1) and transport uphill (2) in a block, then excavate the CT301 transport level tunnel (4), CT301 return air level tunnel (5) and open the cut hole to form a complete production system;

[0027] S2 and CT301 adopt the high-porosity filling technology of gangue after support for mining, and use the gob-side retaining technology to retain the CT301 return air level tunnel (5), and use the side support body (12) to reinforce it, which serves as the CO2 injection tunnel of this working face and the transportation tunnel of CT302;

[0028] When the S3 and CT301 working faces advance 400m, a 7m thick closed wall (10) is used to isolate the working face from the rear goaf, forming a closed CO2 storage space; the closed space is composed of the remaining coal pillar (13), the closed wall (10), the roadside support body (12) and the high-porosity waste rock material (13);

[0029] S4. Drill holes are laid out into the CT301 goaf through the CO2 injection tunnel, and CO2 injection pipelines are laid out in the mining tunnel and the drill holes, with a drill hole spacing of 320m.

[0030] S5. CO2 is injected into the goaf through the CO2 injection pipe (7) by the CO2 injection pump (6). After the injection is completed, the injection of CO2 into the next closed space is started until the working face is completely filled. The injection pump pressure is 7.5MPa. The order of CT301 injection of CO2 and CT301 filling and mining is as follows: after CT301 advances 400, a closed wall is laid to form a closed space, the switch valve (11) of the pipeline ① (8) is opened to inject CO2. When the CO2 injection flow rate in the flow sensor (15) remains unchanged, it can be judged that the CO2 injection is completed, the switch valve (11) of the pipeline ① (8) is closed, and the injection of CO2 into the next closed space is carried out until the working face is completely filled, and the CO2 injection pump (6) is turned off.

[0031] The negative carbon same-face filling mining method used in the embodiment has a CO2 storage capacity of 37.4 tons and simultaneously disposes of 3.4 million tons of gangue, achieving the dual purposes of solid waste disposal and CO2 storage and realizing green mining of coal resources.

[0032] The technical means disclosed in the solutions of the present invention are not limited to those disclosed in the above-mentioned embodiments, but also include technical solutions composed of any combination of the above-mentioned technical features. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A negative carbon same-surface filling system arrangement and mining method, characterized in that: The steps include: S1, excavate the return air uphill (1) and transport uphill (2) in a block, then excavate the CT301 transport level tunnel (4), CT301 return air level tunnel (5) and open the cut hole to form a complete production system; S2 and CT301 adopt the high-porosity filling technology of gangue after support for mining, and use the gob-side retaining technology to retain the CT301 return air level tunnel (5), and use the side support body (12) to reinforce it, which serves as the CO2 injection tunnel of this working face and the transportation tunnel of CT302; When the S3 and CT301 working faces advance 300 to 500 m, a closed wall (10) is used to isolate the working face from the goaf behind, forming a closed CO2 storage space; S4. Drill holes are laid out in the CT301 goaf through the CO2 injection tunnel, and CO2 injection pipes (7) are arranged in the mining tunnel and the drill holes. S5, CO2 is injected into the goaf through the CO2 injection pipe (7) by the CO2 injection pump (6). After the injection is completed, the injection of CO2 into the next confined space is started until the working face is completely filled; In step S3, the closed wall (10) is made of fly ash, cement and gangue, and has a thickness of 5 to 10 m; In step S3, the enclosed CO2 storage space is composed of an enclosed wall (10), a coal pillar (13), a roadside support body (12) and a high-porosity gangue material (14); In step S5, the CO2 injection pump (6) is arranged in the chamber of the transport uphill (2), and the injection pump pressure is greater than 7.5 MPa; In step S5, the order of CT301 injection of CO2 and CT301 filling mining is as follows: after CT301 advances a certain distance, a closed wall (10) is laid out to form a closed space, the switch valve (11) of pipeline ① (8) is opened to inject CO2, and after the injection is completed, the switch valve (11) of pipeline ① (8) is closed, and the injection of CO2 into the next closed space is carried out until the working face is filled and the CO2 injection pump (6) is turned off.

2. The negative carbon same-surface filling system arrangement and mining method according to claim 1 is characterized in that: In step S4, the spacing between the boreholes is greater than 300m, and one borehole is arranged in each closed CO2 storage space, located in the middle of the closed space.

3. The negative carbon same-surface filling system arrangement and mining method according to claim 1 is characterized in that: In step S5, the flow sensor (15) arranged in the CO2 filling pipe (7) is used to determine whether the filling is completed. When the CO2 injection flow rate in the flow sensor (15) remains unchanged, it can be determined that the CO2 filling is completed.

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