A fire prevention and extinguishing method for storing CO2 by filling and retaining lanes along the empty space in super coal seam mining

Abstract

The present invention discloses a fire prevention and extinguishing method for filling and retaining lanes along the goaf during super-coal seam mining and sealing CO2, which belongs to the technical field of comprehensive goaf management; it includes the following steps: preparation of filling materials, calculation of the dimensions of the top and bottom plates and the filling process, determination of the lane retaining method, reinforcement of the filling area, measures for preventing air leakage in the lane retaining, sealing CO2, and solidifying CO2. The present invention realizes super-coal seam mining of coal seams by increasing the mining thickness of the top and bottom plates, and injects CO2 to further suppress ignition, thereby eliminating the material basis for spontaneous ignition in the goaf. At the same time, the gangue obtained by increasing the mining thickness of the top and bottom plates and the selected coal gangue are used to realize partial filling of the goaf in situ, so that the original supporting coal pillars in the goaf can be completely replaced to realize lane retaining along the goaf, thereby reducing the support cost; the present method can prevent spontaneous ignition in the goaf and play a role in controlling surface subsidence, and also has the function of utilizing the goaf to seal and solidify CO2 and conduct real-time monitoring.

Description

Technical Field

[0001] The present invention belongs to the technical field of goaf management, and specifically relates to a filling technology for the top cut floor of a coal mining working face, and more specifically, to a goaf filling technology for sealing CO2 in a lane along a super coal seam mining. 2 Fire prevention and extinguishing methods. Background Art

[0002] At present, with the continuous mining of coal seams, coal mining work is becoming more and more difficult and dangerous, especially when mining coal seams that are prone to spontaneous combustion. Due to the high possibility of causing fires and the difficulty of handling and controlling fires underground, it will bring greater danger to the workers.

[0003] The goaf of the working face is the key area for fire. It is necessary to predict the possible fire sites in advance and take corresponding measures to prevent them. It is also necessary to summarize the relationship between the various factors of natural fire in the goaf in a timely manner, coordinate the various factors, master the laws, destroy the necessary conditions for fire, and provide better conditions and guarantees for mining. Goaf fire prevention and extinguishing has always been a key issue for researchers in this field, and it is urgent to explore an effective goaf fire prevention and extinguishing method. Summary of the invention

[0004] The present invention aims to solve the technical problems existing in the prior art and provide a method for storing CO2 in the tunnel along the empty filling in super coal seam mining. 2 Fire prevention and extinguishing methods.

[0005] To solve the above technical problems, the present invention comprises the following steps:

[0006] Step 1: Preparation of filling materials;

[0007] Step 2: Calculation of the dimensions of the top cutting floor and the filling process: including the width of the over-mining filling, the width of the selected waste filling and the width of the total filling area;

[0008] Step 3: Determine the lane retention method: The first mining face adopts the longwall forward mining method, the ventilation method adopts the "U-shaped" ventilation method, and the working face realizes double-side filling and double-retained lanes; after the first mining face is mined, the adjacent working face adopts the longwall retreat mining method, the ventilation method adopts the "Z-shaped" ventilation method, and the adjacent working face realizes single-side filling and single-retained lanes;

[0009] Step 4: Reinforcement of filling area;

[0010] Step 5: Measures to prevent air leakage in lanes;

[0011] Step 6: Storing CO 2 :The goaf formed after mining by filling method is CO 2 The storage of CO2 Inject it into the goaf through the conveying device to achieve the goaf's CO 2 of storage;

[0012] Step 7: Solidification of CO 2 : After the mining of the working face is completed, a closed space can be formed, or after the mining of the entire mining area is completed, alkaline solid waste materials can be filled to solidify CO 2 ;

[0013] Step 8: Monitoring the stored CO 2 Leakage: Fill sulfur hexafluoride gas to trace carbon dioxide gas, and use the "three-in-one" monitoring method to set up electron capture detectors (ECDs) in the return airway, key layer, and surface of the goaf. They only have signals for electronegative substances, that is, only for SF6; connect the sensor to a handheld gas chromatograph that can be observed at any time, so as to monitor CO in the goaf. 2 Is there a purpose for the leak?

[0014] Preferably, the working face adopts a top-cutting and filling mode of mining, selection, cutting and filling, and all the filling materials come from part of the top and bottom plates cut from the coal mining area of ​​the working face and the sorted coal gangue. The principle of top-cutting and bottom-cutting filling mining is that the cutting and filling volumes are equal.

[0015] Preferably, in step 2, the size calculation of the top and bottom plate filling is as follows:

[0016] Q w Q h K = C w C h

[0017] In the formula, Q w —Width of the cut-top floor area, m;

[0018] Q h —Height of the cut-off bottom plate area, m;

[0019] K —Broken gangue expansion coefficient;

[0020] C h —Height of the filling area, m;

[0021] C w —Width of the filling area, m;

[0022] The total filling area width is calculated as:

[0023] The total filling area width = over-mining filling width + selected waste filling width.

[0024] Preferably, the backfill area is reinforced by filling and grouting. Before grouting, it is compacted by a tamping device and reinforced with a metal mesh. The grouting material is prepared, and then the gangue in the backfill area is filled and grouted by anchor cables.

[0025] Preferably, the measures for preventing air leakage in the lane are:

[0026] All tunnels along the air are sprayed along their entire length, with a thickness of no less than 50mm, covering the sides and 1 / 2 of the roof along the air, blocking air leakage channels.

[0027] Preferably, CO is stored 2 The steps are:

[0028] The collected CO 2 CO temporarily stored in coal mines 2 The CO 2 The storage tank is connected to the compressor, one end of the compressor is connected to the storage tank, and the other end of the compressor is directly connected to the goaf through a transmission pipeline. 2 Injected into the goaf through the transmission pipeline.

[0029] Preferably, the working face adopts the method of filling and retaining the lane to achieve the lane formation.

[0030] Preferably, the roof and floor are over-mined to remove some rock until there is no coal left in the goaf.

[0031] Preferably, coal seam mining at the working face and filling of goafs are performed simultaneously and independently of each other.

[0032] Preferably, use SF 6 CO 2 Tracing is performed, and then real-time monitoring is performed using a gas chromatograph equipped with an ECD detector.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention provides a method for storing CO by filling and retaining lanes along the super coal seam mining. 2 The fire prevention and extinguishing method is used to prevent the occurrence of natural fires in mining areas. On the one hand, the invention realizes full mining of coal seams by increasing the mining thickness of the top and bottom plates, so that there is no coal left in the goaf, and CO is filled in. 2, further suppressing the ignition, theoretically eliminating the material basis for the spontaneous combustion of the goaf, thereby achieving the purpose of preventing the occurrence of natural fires in the goaf; on the other hand, the extra rock, gangue and selected coal gangue obtained by increasing the mining thickness of the roof and floor plates are used to partially fill the goaf in situ, thereby completely replacing the supporting coal pillars, which is not only simple to operate, but also energy-saving and environmentally friendly; and in-situ filling also reduces the support cost of the goaf accordingly, which can not only prevent the spontaneous combustion of the goaf, but also save support costs, control surface subsidence, save coal resources, and utilize the goaf to seal and solidify CO 2 It also has the function of real-time monitoring, and has great prospects for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0036] Figure 1 It is a schematic diagram of the implementation process of the present invention;

[0037] Figure 2 It is a cross-sectional schematic diagram of the cut-top bottom plate area of ​​the present invention;

[0038] Figure 3 It is a plan view of the filling area of ​​the present invention;

[0039] Figure 4 This is a schematic diagram of double-side filling and double-retaining lanes in the first mining working face of the present invention;

[0040] Figure 5 This is a schematic diagram of the first mining face after mining is completed in the present invention;

[0041] Figure 6 This is a schematic diagram of a single lane reserved for single-side filling near the working face of the present invention.

[0042] Symbols in the figure:

[0043] 1. Roof area; 2. Floor area; 3. Over-exploited part; 4. Coal seam part; 5. Filling area; 6. Gob-side tunnel; 7. Goaf area; 8. Working face; 9. First mining working face; 10. Adjacent working face; 11. Working face to be mined; 12. Upper drift; 13. Lower drift; 14. Return air downhill passage; 15. Track downhill passage; 16. Belt downhill passage. DETAILED DESCRIPTION

[0044] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0045] See also Figure 1-Figure 3 The present invention provides a method for storing CO2 by filling and retaining lanes along the super coal seam mining 2 The fire prevention and extinguishing method specifically includes the following steps:

[0046] Step 1: Preparation of filling materials;

[0047] Step 2: Calculation of the dimensions of the top cutting floor and the filling process: including the width of the over-mining filling, the width of the selected waste filling and the width of the total filling area;

[0048] Step 3: Determine the lane retention method: The first mining face adopts the longwall forward mining method, the ventilation method adopts the "U-shaped" ventilation method, and the working face realizes double-side filling and double-retained lanes; after the first mining face is mined, the adjacent working face adopts the longwall retreat mining method, the ventilation method adopts the "Z-shaped" ventilation method, and the adjacent working face realizes single-side filling and single-retained lanes;

[0049] Step 4: Reinforcement of filling area;

[0050] Step 5: Measures to prevent air leakage in lanes;

[0051] Step 6: Storing CO 2 :The goaf formed after mining by filling method is CO 2 The storage of CO 2 Inject it into the goaf through the conveying device to achieve the goaf's CO 2 of storage;

[0052] Step 7: Solidification of CO 2 : After the mining of the working face is completed, a closed space can be formed, or after the mining of the entire mining area is completed, alkaline solid waste materials can be filled to solidify CO 2 ;

[0053] Step 8: Monitoring the stored CO 2 Is there a leak?

[0054] Specifically, CO storage 2 The methods for monitoring whether there is a leak are:

[0055] Sulfur hexafluoride gas is filled to trace carbon dioxide gas, and the "three-in-one" monitoring method is used to set up electron capture detectors (ECDs) in the return airway of the goaf, key layers, and the surface. They only have signals for substances with electronegativity, that is, only for SF 6There is a signal; the sensor is connected to a handheld gas chromatograph that can be easily observed at any time to monitor the CO in the goaf. 2 Is there a purpose for the leak?

[0056] Embodiment 1

[0057] like Figure 2 , Figure 3 As shown in the figure, the arrangement of the top and bottom plates is as follows: 1 is the top plate area, 2 is the bottom plate area, 3 is the over-exploited part, 4 is the coal seam part, 5 is the filling area, 6 is the goaf-side tunneling, 7 is the goaf area, and 8 is the working face.

[0058] Specifically, the working face is formed into a lane using a filling method.

[0059] The filling area 5 is formed by filling the roadways on both sides of the working face 8, and some rocks are over-mined in the roof area and the floor area until there is no coal left in the goaf.

[0060] Furthermore, the coal seam mining and goaf filling of the working face are carried out simultaneously and independently of each other, and the gangue mined from the over-mined part 3 of the roof and floor plates and some selected coal gangue mixture are used for filling on site.

[0061] The fire-proof top and bottom plate filling method adopted by the present invention realizes super-coal seam mining by increasing the mining thickness of the top and bottom plates, and filling CO 2 , further suppressing the ignition, eliminating the material basis for spontaneous ignition in the goaf, and at the same time using the gangue obtained by increasing the mining thickness of the roof and floor plates and the sorted coal gangue to partially fill the goaf in situ, it can completely replace the original supporting coal pillars in the goaf to achieve goaf-side lane retention and reduce support costs; this method can not only prevent spontaneous ignition in the goaf and play a role in controlling surface subsidence, but also use the goaf to seal and solidify CO 2 It also has the function of real-time monitoring, and has great application prospects.

[0062] Embodiment 2

[0063] The specific filling method of the cut top bottom plate includes the following steps:

[0064] Prepare filling material:

[0065] Since the top and bottom plates of the working face are filled in a top-cutting and filling mode of mining, all the filling materials come from part of the top and bottom plates cut from the coal mining area of ​​the working face and the sorted coal gangue. One of the principles of top-cutting and bottom plate filling mining is that the cutting and filling volumes are equal, that is, the volume of gangue formed after the top-cutting and bottom plates are crushed is equal to the filling volume. By determining the parameters of the top-cutting and bottom plate area, the parameters of the corresponding filling area can be determined.

[0066] Calculation of the dimensions of the cutting top, bottom plate and filling process:

[0067] Taking into account the crushing and expansion characteristics of the broken waste rock after the top plate is cut, the corresponding size parameters of the top plate filling can be calculated according to the following formula. The equal cutting and filling volumes realize the self-sufficiency of the filling materials along the void and ensure the dense and reliable filling effect. The specific calculation formula is:

[0068] Q w Q h K = C w C h

[0069] In the formula, Q w —Width of the cut-top floor area, m;

[0070] Q h —Height of the cut-off bottom plate area, m;

[0071] K —The expansion coefficient of crushed gangue is generally 1.4 or 1.5;

[0072] C h —Height of the filling area, m;

[0073] C w —Width of the filling area, m;

[0074] In the top cutting and filling mode of mining, cutting and filling, the gangue separated from the underground coal gangue accounts for approximately 15%-20% of the mined coal volume, which can be used as an auxiliary filling material for the top cutting floor filling. Without increasing the strength of the top cutting floor or being unable to further increase the strength of the top cutting floor, it can enhance the filling effect and reduce environmental impact.

[0075] Furthermore, it is assumed that the width of the working face (i.e. the width of the roof and floor area) is 200 m, the thickness of the coal seam is 1.6 m, the overmining height is 0.4 m (the roof and floor are 0.2 m each), the total mining thickness is 2 m, and the gangue expansion coefficient is 1.5;

[0076] 1) Over-mining filling width

[0077] Substituting the above formula into the calculation, the width of over-mined waste rock filling can be obtained:

[0078] 200﹡0.4﹡1.5=2﹡Width of over-mining and filling

[0079] Width of overmining fill = 60 m;

[0080] 2) Selected gangue filling width

[0081] Considering the excavation of rock tunnels in the mining area, the coal seam intercalated with gangue accounts for about 20% of the mined coal volume. According to the principle of equal mining and filling volumes, the width of the selected gangue filling can be calculated:

[0082] 200﹡1.6﹡working surface length﹡20%=selected waste filling width﹡2﹡working surface length

[0083] Width of selected waste filling = 32 m;

[0084] 3) Total filling area width

[0085] Total filling area width = over-mining filling width + waste filling width

[0086] Therefore, the total filling area width is 92 m.

[0087] The plane filling rate is close to 50%, effectively achieving the goal of controlling and reducing subsidence.

[0088] Determine the lane retention method:

[0089] Figure 4 , Figure 5 and Figure 6 Among them, 9 is the first mining working face, 10 is the adjacent working face, 11 is the working face to be mined, 12 is the upper drift, 13 is the lower drift, 14 is the return air downhill passage, 15 is the rail downhill passage, and 16 is the belt downhill passage.

[0090] like Figure 4 As shown, in this embodiment, the first mining face adopts the longwall forward coal mining method, the ventilation method adopts the "U-shaped" ventilation method, the drifts on both sides of the working face are formed by filling along the air, and the working face realizes double filling along the air and double reserved lanes.

[0091] After the first mining face is mined, the longwall retreat mining method is adopted in the adjacent working face, and the "Z-type" ventilation method is adopted. The drift on the other side of the working face is formed by filling along the air, and the adjacent working face realizes single filling along the air and single retained lane.

[0092] Thus, when cutting the top and bottom plates, the thickness of the top and bottom plates can be halved, or only the top or bottom plates can be cut, such as Figure 2 shown.

[0093] The mining methods of the subsequent working faces can be repeated for the first and adjacent working faces.

[0094] Reinforcement of filling area:

[0095] The reinforcement method uses filling grouting to achieve dense reinforcement.

[0096] The appropriate grouting method is selected according to the needs. The present invention adopts a pure pressure or continuous grouting method to prepare the raw materials required for filling grouting. Usually, silicate cement and grade II fly ash are selected and mixed in proportion. A grouting pump is used to perform grouting through anchor cables. The gangue in the filling area is filled and grouted through the anchor cables to achieve dense reinforcement of the filling area.

[0097] Furthermore, before grouting, it can also be compacted multiple times by a compacting device to further ensure the filling rate, and reinforced with a metal mesh; the lateral support metal mesh automatically unfolds as the protective bracket moves forward, and when the lateral support metal mesh is unfolded a certain distance, anchor cables are installed on the top and bottom plates to fix the lateral support metal mesh.

[0098] Measures to prevent air leakage in lanes:

[0099] Storing CO 2 Before that, it was necessary to take measures to prevent air leakage in the lanes to ensure that there was no air leakage in the lanes, thus ensuring CO 2 The effect of sealing.

[0100] The specific measures are to spray grout along the entire length of the tunnel along the empty space, and the thickness of the spray grout should not be less than 50mm, covering 1 / 2 of the tunnel side and roof along the empty space to block the air leakage channel; thus making the waste rock filling area more compact and airtight, achieving the purpose of preventing air leakage.

[0101] Furthermore, for key hidden danger locations such as the coal body crushing section of the working face, the section with developed roof cracks, and before and after the fault zone, fire-fighting materials such as spraying LFM light spray materials can be used to take measures in advance to prevent accidents.

[0102] Storing CO 2 :

[0103] The goaf formed by the above filling method is CO 2 Storage provides a huge underground space, which can be fully utilized for CO 2 Storage of CO 2 The steps are:

[0104] First, CO 2 CO emitted by emission sources 2 Capture the collected CO 2 CO temporarily stored in coal mines 2 The CO 2 The storage tank is connected to the compressor through a pipeline, so that one end of the compressor is connected to the storage tank, and the other end of the compressor is directly connected to the goaf through a transmission pipeline; finally, CO 2 Inject it into the goaf through the transmission pipeline to achieve CO 2 of storage.

[0105] Fixing CO 2 :Using alkaline materials to solidify CO 2 .

[0106] Monitoring of stored CO 2 Is there a leak:

[0107] Sulfur hexafluoride gas is filled to trace carbon dioxide gas, and the "three-in-one" monitoring method is used to set up electron capture detectors (ECDs) in the return airway of the goaf, key layers, and the surface. They only have signals for substances with electronegativity, that is, only for SF 6 The sensor is connected to a handheld gas chromatograph that can be easily observed at any time to monitor the CO in the goaf. 2 Is there a purpose for the leak?

[0108] The present invention provides a method for storing CO by filling and retaining lanes along the super coal seam mining. 2 The fire prevention and extinguishing method is used to prevent the occurrence of natural fires in mining areas. On the one hand, the invention realizes full mining of coal seams by increasing the mining thickness of the top and bottom plates, so that there is no coal left in the goaf, and CO is filled in. 2 , further suppressing the ignition, theoretically eliminating the material basis for the spontaneous combustion of the goaf, thereby achieving the purpose of preventing the occurrence of natural fires in the goaf; on the other hand, the extra rock, gangue and selected coal gangue obtained by increasing the mining thickness of the roof and floor plates are used to partially fill the goaf in situ, thereby completely replacing the supporting coal pillars, which is not only simple to operate, but also energy-saving and environmentally friendly; and in-situ filling also reduces the support cost of the goaf accordingly, which can not only prevent the spontaneous combustion of the goaf, but also save support costs, control surface subsidence, save coal resources, and utilize the goaf to seal and solidify CO 2 It also has the function of real-time monitoring, and has great prospects for promotion and application.

[0109] In the description of the present invention, it is necessary to understand that the orientation or positional relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0110] In addition, in the description of the present application, “plurality” means two or more than two, unless otherwise clearly and specifically defined.

[0111] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A fire prevention and extinguishing method for storing CO2 by filling and retaining lanes along the empty space in super coal seam mining, characterized in that: The following steps are involved: Step 1: Preparation of filling materials; the working face adopts the top-cut filling mode of mining, selection, cutting and filling. The filling materials all come from the top and bottom plates cut from the coal mining area of ​​the working face and the selected coal gangue. The principle of top-cut and bottom-cut filling mining is that the cutting and filling volumes are equal; Step 2: Calculation of the dimensions of the top cutting floor and the filling process: including the width of the over-mining filling, the width of the selected waste filling and the width of the total filling area; Step 3: Determine the lane retention method: The first mining face adopts the longwall forward mining method, and the ventilation method adopts the "U-shaped" ventilation method. The first mining face realizes double-side filling and double lane retention; after the first mining face is mined, the adjacent working face adopts the longwall retreat mining method, and the ventilation method adopts the "Z-shaped" ventilation method. The adjacent working face realizes single-side filling and single lane retention; Step 4: Reinforcement of filling area; Step 5: Measures to prevent air leakage in lanes; Step 6: Seal CO2: The goaf formed after mining by the filling method provides an operating space for the storage of CO2. CO2 is injected into the goaf through a conveying device to achieve the sealing of CO2 in the goaf; Step 7: Solidifying CO2: After the mining of the working face is completed or the mining of the entire mining area is completed, fill in alkaline solid waste materials to solidify CO2; Step 8: Monitor the stored CO2 for leakage.

2. A fire prevention and extinguishing method for storing CO2 in the empty filling lane during super coal seam mining according to claim 1, characterized in that: In step 2, the size calculation of the top and bottom plate filling is as follows: Q w Q h K = C w C h In the formula, Q w —Width of the cut-top floor area, m; Q h —Height of the cut-off bottom plate area, m; K —Broken gangue expansion coefficient; C h —Height of the filling area, m; C w —Width of the filling area, m; The total filling area width is calculated as: The total filling area width = over-mining filling width + selected waste filling width.

3. A fire prevention and extinguishing method for storing CO2 by filling and retaining lanes along the super coal seam mining according to claim 1, characterized in that: The filling area is reinforced by filling and grouting. Before grouting, it is compacted by a tamping device and reinforced with a metal mesh. The grouting materials are prepared, and then the gangue in the filling area is filled and grouted by grouting anchor cables.

4. A fire prevention and extinguishing method for storing CO2 by filling and retaining lanes along the super coal seam mining according to claim 1, characterized in that: The steps to store CO2 are: The collected CO2 is temporarily stored in the CO2 storage tank of the coal mine, and then the CO2 storage tank is connected to the compressor. One end of the compressor is connected to the storage tank, and the other end of the compressor is directly connected to the goaf through a transmission pipeline. Finally, the CO2 is injected into the goaf through the transmission pipeline.

5. A fire prevention and extinguishing method for storing CO2 by filling and retaining lanes along the super coal seam mining according to claim 1, characterized in that: The working face adopts the method of filling and retaining lanes, and the drifts on both sides of the working face are filled with over-mined gangue to form lanes.

6. A fire prevention and extinguishing method for storing CO2 by filling and retaining lanes along the super coal seam mining according to claim 1, characterized in that: The roof and floor plates are over-mined until there is no coal left in the goaf.

7. A fire prevention and extinguishing method for storing CO2 by filling and retaining lanes along the super coal seam mining according to claim 1, characterized in that: Coal seam mining at the working face and filling of goaf areas are carried out simultaneously and independently of each other.

8. A fire prevention and extinguishing method for storing CO2 by filling and retaining lanes along the super coal seam mining according to claim 1, characterized in that: SF6 is used to trace CO2, and a gas chromatograph equipped with an ECD detector is used for real-time monitoring.

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