A method for closing and grouting out fire in goaf of longwall fully-mechanized face in strike of near-horizontal coal seam

Abstract

The application provides a kind of near horizontal coal seam strike long wall fully mechanized coal face goaf closure grouting fire extinguishing method, comprising the following steps: S1, constructs the spray grouting closure zone;S2, constructs the first full-face filling support zone;S3, constructs the second full-face filling support zone;S4, constructs the full-face filling support zone;S5, grouting fire extinguishing;The fire extinguishing method of the application can effectively control the fire problem of near horizontal coal seam strike long wall fully mechanized working face goaf, solves the problem of high concentration CO stored in working face goaf escaping along the working face, improves the safety level, increases the safety benefit and social benefit, and provides protection for mine safety production and workers' physical and mental health.

Description

Technical Field

[0001] This invention relates to the field of fire control technology when a fire breaks out in the goaf of a fully mechanized coal mining face, specifically a method for sealing and grouting to extinguish a fire in the goaf of a near-horizontal coal seam longwall fully mechanized mining face. Background Technology

[0002] Fires in the goaf of a coal mining face are a serious disaster in underground coal mine safety production. Toxic and harmful gases such as CO in the goaf can enter the working space of personnel, posing a significant threat to the life safety and health of workers, and under certain conditions, there is a risk of gas explosion.

[0003] When a fire breaks out in the goaf of a fully mechanized mining face, the exact location of the ignition point is usually unknown, and the total amount of grouting or spreading in the pre-embedded pipelines of the working face is insufficient, resulting in an ineffective fire extinguishing effect. Currently, fire extinguishing methods commonly used include drilling fire extinguishing holes in the return airway or transport roadway, as well as rapid side-pushing and backfilling of corners in the working face. The main problems with fire extinguishing drilling in return airways or transport roadways are as follows: First, the drill bit is easily jammed when it encounters loose and hard coal (rock) near the goaf, preventing the drilling from reaching the depth behind the support frame. Even if the drilling reaches the depth of the goaf, the grouting fluid may be missed near the top cut line due to encountering fracture zones in the goaf, and thus cannot reach the deeper parts of the goaf. Second, the ignition point in the goaf is unclear, and the grouting borehole cannot be accurately designed to the predetermined position. In addition, the grouting fluid is difficult to reach the ignition point in a short time due to the slope of the goaf floor. Third, when the rock blocks in the heat dissipation zone and oxidation zone of the goaf are large and hard, the grouting fluid is prone to leakage or overflow through the roadway, resulting in unsatisfactory effects.

[0004] The method of rapid face-pushing and corner-filling mining aims to isolate the goaf after the top coal collapses, preventing airflow from entering the goaf and quickly eliminating the fire zone. However, this approach has several problems during the early stages of face-pushing mining: First, in the initial mining phase, when the coal seam roof is hard and difficult to collapse, the old roof in the goaf cannot be properly secured, resulting in numerous gaps and failing to achieve the expected roof-sealing effect, leading to ineffective fire suppression. Second, the hard and difficult-to-break top coal, coupled with the presence of large coal and rock blocks in the goaf, causes airflow leakage through the gaps between these blocks, making it difficult to achieve the desired sealing effect when releasing coal. Third, the face-pushing progress is affected by objective conditions, and the progress may not meet the planned target. Due to these reasons, the fire prevention and suppression effect in the early stages of face-pushing mining is not ideal. Summary of the Invention

[0005] To address the aforementioned technical shortcomings, the purpose of this invention is to provide a method for sealing and grouting fire extinguishing in the goaf of a near-horizontal coal seam longwall longwall mining face, thereby blocking gas leakage from the goaf and achieving rapid fire extinguishing.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for sealing and grouting fire extinguishing in the goaf of a near-horizontal coal seam longwall mining face includes the following steps:

[0008] S1. Construct a shotcrete sealing zone

[0009] 1) First, inject inert bubbles into the goaf and its upper and lower corners;

[0010] 2) Install shotcrete machines in the transport roadway to seal the gaps in the loose coal blocks that have fallen behind the frame;

[0011] S2. Construct the first full-section filling support strip.

[0012] 1) The hydraulic supports adjacent to each other on the working face are staggered for support, freeing up working space behind the frame;

[0013] 2) Shotcrete and inert foam are injected behind the hydraulic support in the working face where there is space; in the cleared working space behind the frame, wooden stacks are made to form a temporary support enclosure behind the frame;

[0014] 3) Move the hydraulic supports that are staggered in front of the working face forward to be level with them, and densify the temporary support belt behind the hydraulic supports at intervals of 3-5m after the timber stacks form a frame. At the same time, install fiberglass anchor bolts on the top plate of the working face to lift the roof.

[0015] 4) Fill the gaps between adjacent timber stacks with sandbags, and use a shotcrete machine to fill all gaps with shotcrete, ensuring that the timber stacks and sandbags are tightly connected to the top; so that the first full-section filling support belt integrating support, filling and sealing is formed behind the frame.

[0016] S3. Construct the second full-section filling support strip.

[0017] 1) Open 2-3 sides forward on the working face, and stack wooden stacks at intervals behind the frame according to the method in step S2 to form a second temporary support enclosure behind the frame;

[0018] 2) Fill the gaps between adjacent timber stacks with sandbags, and use a shotcrete machine to fill all gaps with shotcrete, ensuring that the timber stacks and sandbags are tightly connected.

[0019] 3) Support and fill the entire cross-section of the working face to form a sealed wall structure of support and filling behind the working face frame;

[0020] 4) The sealed wall structure is filled with shotcrete to fill all gaps and form a second full-section filling support strip;

[0021] S4. Constructing multiple full-section filling support strips

[0022] After the second full-section filling support strip is formed, it is determined whether more sealing walls need to be set up depending on the sealing of the goaf area of ​​the working face. If so, the working face is opened 2-3 sides forward, and several full-section filling support strips are set up in the same way as step S3. All gaps between two adjacent full-section filling support strips are filled with grout and sealed tightly.

[0023] S5, Grouting fire extinguishing

[0024] The grouting pipeline was connected, the working face was stopped, and centralized grouting and fire extinguishing were carried out in the goaf area.

[0025] Preferably, in steps S2 and S3, while stacking timber and filling sandbags, grouting pipelines are pre-buried in sections along the working face.

[0026] Preferably, in step S3(1), the interval between two adjacent stacks of wood is 3-5m.

[0027] Preferably, in step S3, 4), the thickness of the sprayed grout on the surface of the sealing wall structure is more than 10 cm.

[0028] Preferably, during the construction of the sealing wall, the floating coal and slag on the bottom plate should be cleaned thoroughly to expose the solid bottom, and the bottom plate should be filled with sprayed grout.

[0029] Preferably, the materials required for the construction process are transported by a front scraper conveyor.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] The fire extinguishing method of this invention involves establishing a fire-extinguishing sealing wall behind the support of the fully mechanized mining face. This sealing wall is constructed using spraying and filling techniques, creating a complete enclosure and seal within the fire area of ​​the goaf. Then, centralized grouting is performed using grouting pipelines. This involves injecting inert bubbles into the goaf, spraying grout to fill gaps in the goaf or fallen rock, blocking air leakage, and preventing the risk of gas overflow from the goaf. Materials are transported by a front scraper conveyor to quickly construct a sealed fire wall behind the support. Grouting pipelines are pre-embedded, and finally, centralized grouting is performed to extinguish the fire. This method offers short disaster control time and is highly effective. It is highly reliable and can effectively solve the problems of traditional fire prevention and extinguishing methods described in the "Background Technology". It uses materials such as shotcrete machines and pipelines, square timber, sand, cement, fiberglass anchors and grouting pipelines, which are low in cost, fast in effect and simple in process. It can effectively control the problem of fire in the goaf of longwall mining face near horizontal coal seam, solve the problem of high concentration of CO escaping along the working face from the goaf, improve the level of safety assurance, increase safety benefits and social benefits, and provide protection for mine safety production and the physical and mental health of employees. Attached Figure Description

[0032] Figure 1A layout diagram showing the misalignment arrangement of the hydraulic support for the working face in this invention;

[0033] Figure 2 This is a schematic diagram showing how the hydraulic support for the working face is moved to a level position after the wooden stack is placed behind the support following the front and rear misalignment in this invention.

[0034] Figure 3 This is the overall construction layout plan of the present invention;

[0035] Figure 4 This is a schematic cross-sectional view of the arrangement of the present invention.

[0036] in:

[0037] 1. Shotcrete enclosure; 2. Timber stack; 3. Working space behind the scaffold; 4. Return airway; 5. Hydraulic support for the working face; 6. Transport roadway; 7. Shotcrete machine; 8. Grouting pipeline; 9. Sandbags; 10. Fiberglass anchor bolts. Detailed Implementation

[0038] The invention will now be further described with reference to the accompanying drawings.

[0039] A method for sealing and grouting fire extinguishing in the goaf of a near-horizontal coal seam longwall mining face includes the following steps:

[0040] S1, Construct a shotcrete sealing zone 1

[0041] 1) After the goaf of the longwall longwall mining face near the horizontal coal seam is ignited, inert bubbles are first injected into the goaf and the upper and lower corners to fill the gaps in the goaf or the fallen gangue, block air leakage, and prevent the danger of gas overflow from the goaf.

[0042] 2) A shotcrete machine 7 is installed in the transport roadway 6 to spray grout into the gaps of loose coal behind the frame, forming a shotcrete sealing zone 1 to isolate oxygen from entering or reduce the amount of air entering and block the overflow of harmful gases.

[0043] S2. Construct the first full-section filling support strip.

[0044] 1) The hydraulic supports adjacent to each other on the working face are staggered for support, freeing up working space 3 behind the frame, see Figure 1 ;

[0045] 2) Shotcrete and inert foam injection are carried out behind the hydraulic support 5 in the working area where there is space; in the cleared working space 3 behind the frame, wooden stacks 2 are used to form a temporary support enclosure behind the frame, see Figure 1 ;

[0046] 3) Move the hydraulic supports, which were initially staggered in front of the working face, forward to align them. Behind the hydraulic supports, densify the temporary support strip behind the timber stacks (2 sections) at 3-5m intervals. Simultaneously, install 10 fiberglass anchor bolts on the top of the working face to lift the roof. (See...) Figure 2 ;

[0047] 4) Fill the gaps between adjacent timber stacks 2 with sandbags 9, and fill all gaps with shotcrete using a shotcrete machine 7, ensuring that the timber stacks 2 and the sandbags 9 are tightly connected to the top; so that the first full-section filling support belt integrating support, filling and sealing is formed behind the frame.

[0048] S3. Construct the second full-section filling support strip.

[0049] 1) Open 2-3 sides forward on the working face, and stack 2 wooden stacks at intervals behind the frame according to the method in step S2 to form a second temporary support enclosure behind the frame;

[0050] 2) Fill the gaps between adjacent timber stacks 2 with sandbags 9, and fill all gaps with shotcrete using a shotcrete machine 7, ensuring that the timber stacks 2 and the sandbags 9 are tightly connected.

[0051] 3) Support and fill the entire cross-section of the working face to form a sealed wall structure of support and filling behind the working face frame;

[0052] 4) The sealed wall structure is filled with shotcrete to fill all gaps and form a second full-section filling support strip;

[0053] S4. Constructing multiple full-section filling support strips

[0054] After the second full-section filling support strip is formed, it is determined whether more sealing walls need to be set up depending on the sealing of the goaf area of ​​the working face. If so, the working face is opened 2-3 sides forward, and several full-section filling support strips are set up in the same way as step S3. All gaps between two adjacent full-section filling support strips are filled with grout and sealed tightly.

[0055] S5, Grouting Fire Extinguishing

[0056] Connect grouting pipeline 8, stop advancing the working face, and carry out centralized grouting and fire extinguishing in the goaf area;

[0057] During the construction of the sealing wall structure, materials such as sandbags used on the working face were transported to the construction site via the existing forward conveyor.

[0058] Furthermore, in steps S2 and S3, while stacking the timber stacks 2 and filling the sandbags 9, grouting pipelines are pre-buried in sections along the working face and the return airway 4.

[0059] Furthermore, in step S3(1), the interval between two adjacent stacks 2 is 3-5m.

[0060] Furthermore, in step S3, 4), the thickness of the sprayed grout on the surface of the sealing wall structure is more than 10cm.

[0061] Furthermore, during the construction of the sealing wall, the floating coal and slag on the bottom plate must be thoroughly cleaned to expose the solid bottom, and the bottom plate should be filled with sprayed grout.

[0062] Furthermore, the materials required for the construction process are transported using the existing front scraper conveyor.

Claims

1. A method for closing and grouting a goaf of a longwall face in a coal seam with a near horizontal strike, characterized in that, It comprises the following steps: S1, constructing a shotcrete closed zone (1) 1) First, inject inert bubbles into the gob and upper and lower corners; 2) Configure a shotcrete machine (7) in the transportation crossheading (6) to perform shotcrete sealing on the gaps of the scattered coal blocks behind the supports; S2, constructing the first full-face support and filling zone 1) Set the adjacent hydraulic supports in front and back of the working face to support the space (3) behind the supports; 2) Perform shotcrete and inert bubble injection behind the hydraulic supports in the space of the working face, and use wooden piles (2) to set temporary support and closed zones behind the supports; 3) Move the supports in front and back of the working face forward to align, and set wooden piles (2) at intervals of 3-5 m behind the supports to form temporary support and closed zones, and install glass steel anchor rods (10) to support the roof; 4) Fill sandbags (9) between adjacent wooden piles (2), and use a shotcrete machine (7) to fill all gaps, and ensure that the wooden piles (2) and the filled sandbags (9) are tightly connected to the roof; Form the first full-face support and filling zone with integrated support, filling, and sealing behind the supports; S3, constructing the second full-face support and filling zone 1) Open 2-3 sides of the working face forward, and set wooden piles (2) at intervals behind the supports according to the method in step S2 to form the second temporary support and closed zone behind the supports; 2) Fill sandbags (9) between adjacent wooden piles (2), and use a shotcrete machine (7) to fill all gaps, and ensure that the wooden piles (2) and the filled sandbags (9) are tightly connected to the roof; 3) Support and fill along the full face of the working face to form a sealing wall structure behind the supports of the working face; 4) Perform full-face shotcrete filling on the sealing wall structure to fill all gaps and form the second full-face support and filling zone; S4, constructing multiple full-face support and filling zones After the second full-face support and filling zone is formed, determine whether more closed walls are needed based on the sealing condition of the gob of the working face. If needed, open 2-3 sides of the working face forward, set multiple full-face support and filling zones according to the same method in step S3, and perform shotcrete filling and sealing on all gaps between adjacent two full-face support and filling zones. S5, grouting and fire extinguishing Connect the grouting pipeline (8), stop advancing the working face, and perform concentrated grouting and fire extinguishing on the gob.

2. The method for closing and grouting goaf of longwall face in seam with near horizontal coal seam according to claim 1, characterized in that, In steps S2 and S3, while setting wooden piles (2) and filling sandbags (9), pre-bury the grouting pipeline along the working face.

3. The method for closing and grouting goaf of longwall face in seam with near horizontal coal seam according to claim 1, characterized in that, In step S3 1), the interval between adjacent two wooden piles (2) is 3-5 m.

4. The method for closing and grouting goaf of longwall face in seam with near horizontal coal seam according to claim 1, characterized in that, In step S3 4), the shotcrete thickness of the sealing wall structure surface is more than 10 cm.

Images