Gas extraction device and method in initial mining period of working face of thick coal seam

Abstract

The invention discloses a gas extraction device and method in the initial mining period of a thick coal seam working face, the device comprises a gas extraction module, a comprehensive monitoring module and a distributed extraction control module, the comprehensive monitoring module collects gas parameters in real time, and the distributed extraction control module realizes independent control of an extraction screen pipe through a capsule type valve; the method comprises the following steps: dividing units according to coal seam thickness before stoping, determining extraction intervals, and installing pipelines and modules; after recovery, air return side extraction is preferentially performed, an air inlet side is opened along with propulsion, opening and closing of an extraction screen pipe are intelligently controlled by monitoring gas parameters such as oxygen and carbon monoxide, and extraction is stopped after the basic roof collapses. According to the method, precise dynamic extraction of goaf gas in the initial extraction period is achieved, gas components are synchronously monitored to prevent spontaneous combustion of residual coal, the problems that in the prior art, deep gas treatment is difficult, extraction parameters are lagged and the like are solved, and the extraction efficiency and safety are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mining, and in particular to a gas extraction device and method during the initial mining period of a thick coal seam working face. Background Art

[0002] In the field of coal resource mining, coal mine gas hazards have become a key factor seriously threatening mine safety and production. Gas of varying concentrations and emission patterns can easily cause major safety accidents such as gas explosions, asphyxiation, and coal and gas outbursts. With the continuous increase in coal mining depth and the increasingly complex coal seam conditions, the amount of gas emission has shown a significant upward trend. In particular, with the widespread use of fully mechanized top coal caving in thick coal seams, the amount of gas emission in goafs has increased significantly due to the thick top coal caving thickness and the large amount of coal left behind.

[0003] During the initial mining phase of the working face, that is, from the start of the cut to the initial collapse of the basic roof, there is a lag in roof collapse, the fracture zone is not yet fully developed, and the coal rock compaction in the goaf is low, making the gas enrichment problem particularly prominent. At the same time, in the early stages of the working face advancement, the ventilation system finds it difficult to quickly form a stable negative pressure field, and the fresh air flow cannot effectively dissipate the high concentration of gas on the cut side of the goaf. Especially in the initial pressure stage, the instantaneous impact caused by the roof collapse can easily induce abnormal gas outflow from the goaf, which in turn causes a sharp increase in gas concentration in the return air corner and upper corner areas, resulting in gas exceeding the limit. Therefore, the problem of gas accumulation and abnormal outflow during the initial mining phase of the working face has become an important and difficult problem that needs to be solved urgently for coal mine safety production.

[0004] Currently, to address the problem of excessive gas during the initial mining phase of a working face, the industry primarily employs a system of enhanced extraction technologies for goaf areas, including various gas extraction methods such as high-level drilling, buried pipes, high-extraction lanes, and surface wells. High-level drilling and high-extraction lanes directly extract gas enriched in the goaf by arranging boreholes or lanes in the fractured zone; buried pipe extraction utilizes the principle of negative pressure to extract gas accumulated in the upper corners; and surface wells extract gas from the goaf by drilling vertically down to the coal seam. However, these existing technologies have numerous limitations: high-level drilling and high-extraction lanes are located in fractured zones, making it difficult to effectively extract gas, which primarily accumulates in the caving zone, during the initial mining phase; surface wells are not only expensive to construct but also severely constrained by surface construction conditions; and while buried pipe extraction can improve gas accumulation in the upper corners, it has limited effectiveness in controlling gas deep within the goaf. In addition, the existing gas extraction method mainly relies on manual judgment of the extraction effect and controls the extraction volume by manually adjusting the valve. This method not only consumes a lot of manpower, but also has obvious lag in the adjustment of extraction parameters. Excessive extraction may also aggravate air leakage, further affecting the extraction effect and mine safety.

[0005] To sum up, in view of the shortcomings of the existing technology in gas extraction from goafs during the initial mining period of the working face, it is urgent to develop a new type of gas extraction device and extraction method for goafs during the initial mining period of the working face, so as to achieve efficient control of deep gas in goafs of fully mechanized caving faces in thick coal seams, effectively monitor the gas concentration in goafs, and ensure safe production in coal mines. Summary of the Invention

[0006] The purpose of the present invention is to address the problems of difficulty in controlling deep gas accumulation in goafs, lagging control of extraction parameters, and frequent gas and coal spontaneous combustion disasters in the initial mining period of thick coal seam fully-mechanized caving working faces in the prior art. A gas extraction device and method for the initial mining period of thick coal seam working faces are provided to achieve accurate and dynamic extraction of deep gas accumulated in goafs during the initial mining period of thick coal seam working faces, improve the workflow of manual inspection of extraction effects and management of extraction pipelines, and realize automatic control of extraction.

[0007] To achieve the above-mentioned object, the present invention provides a gas extraction device for the initial mining period of a thick coal seam working face, comprising a comprehensive monitoring module, a distributed extraction control module and a gas extraction module;

[0008] The gas extraction module includes an extraction screen pipe, a screen pipe valve, a pipeline tee, an extraction plug and an extraction main pipe; the screen pipe valve is installed between the upper end opening of the extraction screen pipe and the pipeline tee, and the screen pipe valve is used to control the extraction area and extraction intensity during the installation of the extraction equipment; the pipeline tee connects the screen pipe valve to the extraction main pipe; the extraction plug is installed at the lower end opening of the extraction screen pipe, and is used to connect the comprehensive monitoring module and block the lower end outlet of the extraction screen pipe; the extraction main pipe is a double-layer PVC hollow pipe, and optical fibers and pneumatic bundle tubes are arranged in the interlayer of the extraction main pipe, and are connected to the distributed extraction control module. One end of the extraction main pipe is connected to the extraction main pipe, and the gas extracted by the extraction screen pipe is transported to the mine gas extraction main pipe through the hollow pipeline of the extraction main pipe;

[0009] The comprehensive monitoring module includes a multi-parameter collector, a data transmission pipeline, a data storage device, a logic reader, a clock timer and a signal transmitter; the multi-parameter collector is connected to the extraction screen pipe through the data transmission pipeline to collect the gas temperature and humidity, gas and oxygen concentration parameters in the environment in real time, and transmit them to the data storage device through the data transmission pipeline and the optical fiber in the extraction main pipe interlayer; the data transmission pipeline is an optical fiber for data transmission, which is arranged in the extraction main pipe interlayer; the data storage device modulates and demodulates the received optical signal into a digital signal and stores it in the local space for the logic reader to read and use; the logic reader retrieves the stored gas parameters and comprehensively determines whether gas extraction is required, forms a valve opening and closing command, and sends a signal to the distributed extraction control module through the signal transmitter; the clock timer automatically counts and activates the logic reader at fixed intervals; the signal transmitter transmits the instructions issued by the logic reader or manually to the distributed extraction control module;

[0010] The distributed extraction control module includes a signal receiver, a signal processor, a pneumatic driver, a capsule valve and a pneumatic bundle tube; the signal receiver receives the signal sent by the signal transmitter and transmits it to the signal processor; the signal processor converts the valve switch signal into a drive command and transmits it to the pneumatic driver; the pneumatic driver provides opening and closing power for the capsule valve and controls the degree of opening and closing; the capsule valve is arranged in the pipeline tee and is connected to the pneumatic driver through the pneumatic bundle tube. The capsule expands by inflation, blocks the pipeline tee, and closes the corresponding extraction screen pipe; the pneumatic bundle tube is arranged in the interlayer of the extraction main pipe to provide power for the capsule valve.

[0011] The present invention also discloses a gas extraction method during the initial mining period of a thick coal seam working face, which uses the gas extraction device during the initial mining period of a thick coal seam working face. The gas extraction method comprises the following steps:

[0012] Step 1: Before mining, the working face is divided into different units along the dip according to the thickness of the coal seam, and the spacing of the gas extraction devices is determined for each unit;

[0013] Step 2: Extend the extraction pipeline from the return air lane of the working face to the cut-hole location, and lead the line outward along the air intake lane at the air intake interface of the gas extraction module. Install the monitoring host of the integrated monitoring module and the control host of the distributed extraction control module in the air intake lane;

[0014] Step 3: Install the gas extraction module and supporting pipelines along the roadway at the spacing determined in Step 1. Fix the gas extraction module close to the wall and install a protective shell on the outside.

[0015] Step 4: Install the multi-parameter collector of the integrated monitoring module and the capsule valve of the distributed extraction control module at the corresponding positions of the extraction screen and pipeline tee;

[0016] Step 5: Before the working face starts mining, open the return air side screen valve and close the air inlet side screen valve, giving priority to gas extraction at the cut eye; after the working face advances, open the air inlet side extraction screen valve and conduct comprehensive extraction of the cut eye; after the working face starts mining, open the comprehensive monitoring module simultaneously, collect oxygen and carbon monoxide data in the goaf through the comprehensive monitoring module, and judge whether the residual coal has been oxidized based on the carbon monoxide concentration. If the carbon monoxide concentration continues to rise, close the extraction screen at the corresponding position; when the basic roof collapses completely, that is, after the initial mining period is completed, close the extraction main pipe and stop gas extraction in the cut eye area to prevent air leakage from causing spontaneous combustion of the residual coal.

[0017] Furthermore, the step 1 specifically includes the following steps:

[0018] Step 1.1: Before mining at the working face, establish a mathematical mapping relationship between coal seam thickness and the spacing between extraction devices using numerical simulation methods;

[0019] Step 1.2: Divide the cut into different extraction units according to the change in coal seam thickness at the cut, and determine the layout spacing of the gas extraction modules for each extraction unit.

[0020] Furthermore, the step 2 specifically includes the following steps:

[0021] Step 2.1: Install the main valve on the extraction main of the return air lane of the working face, connect the gas extraction module to the air intake lane, and place the gas extraction module on the wall of the cut hole away from the working face;

[0022] Step 2.2: Lead the interlayer pipeline from the outlet of the gas extraction module's main extraction pipe to a suitable location in the air intake tunnel and install a monitoring host. The monitoring host consists of the clock timer, data storage, logic analyzer, and signal transmitter in the integrated monitoring module.

[0023] Step 2.3: Install the control host at the same location as step 2.2 above. The control host consists of the signal receiver, signal processor, and pneumatic driver in the distributed extraction control module; the pneumatic driver is connected to the pneumatic bundle tube in the extraction main pipe interlayer.

[0024] Furthermore, the step 3 specifically includes the following steps:

[0025] Step 3.1: Install the drainage main pipe of the gas drainage module at one end of the distributed drainage control module. The drainage main pipe should be close to the wall on the side away from the mining face of the cut hole. Hang and fix it on the wall anchor net at a height of not less than 2m.

[0026] Step 3.2: Install pipe tees on the main drainage pipe in sequence based on the determined spacing of the gas drainage modules. The openings of the pipe tees hang naturally downward. The first pipe tee is installed starting from the mining side wall of the intake tunnel, and the last pipe tee is installed at the mining side of the return tunnel.

[0027] Step 3.3: Connect the tee pipe downward to the screen valve and the extraction screen pipe. Install the extraction plug at the end of the extraction screen pipe. The lower end of the extraction screen pipe should be at least 0.5m above the ground.

[0028] Step 3.4: Install a metal protective scaffolding on the top of the gas drainage module. The outer width of the scaffolding should be greater than the width of the gas drainage module.

[0029] Furthermore, step 4 specifically includes the following steps:

[0030] Step 4.1: Connect the multi-parameter collector to the lower end of the extraction screen and number it 1#. Connect the data transmission fiber to the interlayer of the extraction main pipe. Pre-connect the other end with a 5-10m data transmission pipeline, extending from the bracket gap to the working face. Protect the end with an extraction plug.

[0031] Step 4.2: After the working face begins to recover, remove the extraction plug at the end of the data transmission pipeline and install the second multi-parameter collector, numbered 2#. Pre-connect a 5-10m data transmission pipeline to the other end of the multi-parameter collector. As the working face advances, continue to connect multi-parameter collectors and number them in sequence.

[0032] Step 4.3: Install the capsule valve in the distributed drainage control module inside the pipeline tee and connect it to the pneumatic bundle pipe in the drainage main interlayer. The capsule valve is not inflated by default and remains open.

[0033] Furthermore, the multi-parameter collectors are arranged in a group at intervals of 30-40m along the cutting direction, and are installed on the nearest extraction screen.

[0034] Furthermore, step 5 specifically includes the following steps:

[0035] Step 5.1: Divide all extraction screens into two parts along the cutting direction, with one half being the air intake side extraction screen and the other half being the return air side extraction screen. Close the capsule valves corresponding to the air intake side extraction screens with air, leaving only the return air side extraction screens. When the working face begins to recover, open the main valve of the extraction main pipe, giving priority to negative pressure extraction on the return air side. This will prevent airflow short-circuiting caused by extraction from the air intake side screens.

[0036] Step 5.2: When the working face is 5m away from the mining, the wall is sealed at the construction end on the air inlet side to prevent airflow short-circuiting caused by extraction on the air inlet side. The capsule valve is deflated through the distributed extraction control module, the extraction screen on the air inlet side is opened, and extraction is carried out in the entire cut-hole area.

[0037] Step 5.3: After a large area of ​​top coal collapse occurs, turn on the integrated monitoring module and read the gas parameters from the multi-parameter collector every 30 minutes to determine the oxygen and gas concentrations in the goaf. This will prevent oxidation of the coal caused by air entering the goaf. If carbon monoxide is present and its concentration continues to rise, close the extraction screens within 20 meters on both sides of the monitoring point.

[0038] Step 5.4: After extraction stops, continue to monitor extraction parameters and read the gas parameters of the multi-parameter collector every 30 minutes. When the gas concentration exceeds the extraction start threshold and the carbon monoxide concentration stops increasing, control the sieve valve of the corresponding extraction sieve to open and resume gas extraction. If the opening conditions are not met, wait another 30 minutes and read the data.

[0039] Step 5.5: After the initial pressure buildup on the basic roof is complete, close the main extraction pipe and stop extracting gas from the cut-eye area to prevent large-scale air leakage from causing spontaneous combustion of the remaining coal.

[0040] Furthermore, in step 5.2, the end blocking wall is formed by stacking yellow mud sand bags and perlite materials, and colloidal foam is injected behind the wall to seal the gap to prevent airflow short-circuiting caused by extraction on the air inlet side.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The present invention provides a gas extraction device and method for the initial mining period of a thick coal seam working face. By combining gas extraction with distributed gas monitoring means, the gas composition inside the goaf can be monitored in real time with higher accuracy and resolution, and the natural combustion index of the residual coal in the goaf can be mastered. The extraction intensity of a single extraction screen pipe can be controlled by each capsule valve to ensure that the extraction effect reaches the expected level while avoiding the natural combustion of the residual coal in the goaf caused by excessive extraction, thereby realizing the simultaneous gas monitoring and gas control work in the goaf during the initial mining period.

[0043] 2. Reasonably adjust the spacing and opening and closing process of the extraction screen pipes. After the working face starts to be mined, give priority to extracting the gas near the cut-eye on the return air side. While ensuring the normal airflow of the working face, gradually increase the extraction intensity. Even if the cut-eye area is drained due to top coal collapse and coal cutting on the working face, the gas concentration in the goaf is reduced. Through extraction, a negative pressure area of ​​the cut-eye is formed, which pulls the fresh air flow of the working face to move deep into the goaf. The gas in the goaf is replaced by air, which solves the problem of gas exceeding the limit caused by large-scale gas outburst in the goaf after large-scale top coal collapse.

[0044] 3. Compared with traditional goaf gas control methods such as high-position drilling and high-extraction lanes, which are mostly arranged in the fracture zone, the height of fracture development during the initial mining of the working face is limited, and high-position drilling and other methods are not effective in controlling goaf gas; gas exceeding the limit is mostly caused by the instantaneous gas outburst after large-scale collapse of the top coal of each layer. The method proposed in the present invention replaces the gas in the goaf with air, which can effectively control the gas accumulation in the coal seam and the goaf, prevent the instantaneous outburst of large amounts of gas, and ensure the smooth mining of the fully mechanized caving face of the thick coal seam. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is an overall structural diagram of a gas extraction device for the initial mining period of a thick coal seam working face in the present invention.

[0046] Figure 2 This is a top view of the layout of a gas extraction device system in the initial mining period of a thick coal seam working face in the present invention.

[0047] Figure 3 This is an end view of the structure inside the interlayer of the extraction main pipe in the present invention.

[0048] Figure 4 It is a cross-sectional view of the extraction main pipe and the extraction valve in the present invention.

[0049] Figure 5 This is an overall flow chart of a gas extraction method for the initial mining period of a thick coal seam working face in the present invention.

[0050] Figure 6 A numerical model for determining the spacing of extraction modules using the numerical simulation method in the present invention.

[0051] Figure 7 This is a comparison chart of the results of determining the spacing of the extraction modules using the numerical simulation method in the present invention.

[0052] In the figure: 1. Extraction screen pipe; 2. Screen pipe valve; 3. Pipeline tee; 4. Extraction plug; 5. Extraction main pipe; 6. Multi-parameter collector; 7. Data transmission pipeline; 8. Capsule valve; 9. Pneumatic bundle pipe; 10. Monitoring host; 11. Control host; 12. Extraction main pipe; 13. Main valve. DETAILED DESCRIPTION

[0053] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail with reference to the embodiments and the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The technical solutions of the present invention will be described in detail below with reference to the embodiments and the accompanying drawings, but the scope of protection is not limited thereto.

[0054] The invention discloses a gas extraction device for use during the initial mining period of a thick coal seam working face.

[0055] Reference Figures 1 to 2 A gas extraction device for the initial mining period of a thick coal seam working face includes a comprehensive monitoring module, a distributed extraction control module, and a gas extraction module; wherein the gas extraction module includes an extraction screen pipe 1, a screen pipe valve 2, a pipeline tee 3, an extraction plug 4, and an extraction main pipe 5; the extraction screen pipe 1 in this embodiment adopts a high-strength PVC hollow pipe with a diameter of 325 mm, and a plurality of sieve holes are opened on the pipe wall of the extraction screen pipe 1. The sieve holes on the extraction screen pipe 1 have an aperture of 10 mm, an axial spacing of 200 mm, and a circumferential spacing of 90°, which are used to extract gas and block small particles of coal rock.

[0056] Reference Figures 1 to 4 The screen tube valve 2 is installed between the upper end opening of the extraction screen tube 1 and the pipeline tee 3. The screen tube valve 2 is used to control the extraction area and extraction intensity during the installation of the extraction equipment; the pipeline tee 3 connects the screen tube valve 2 to the extraction main pipe 5; the extraction plug 4 is installed at the lower end opening of the extraction screen tube 1, which is used to connect the comprehensive monitoring module and block the lower end outlet of the extraction screen tube 1 to improve the extraction efficiency; the extraction main pipe 5 is a double-layer PVC hollow pipe, and optical fiber and pneumatic bundle tube 9 are arranged in the interlayer of the extraction main pipe 5, and are connected to the distributed extraction control module. One end of the extraction main pipe 5 is connected to the extraction main pipe 12, and the gas extracted by the extraction screen tube 1 is transported to the mine gas extraction main pipe 12 through the hollow pipeline of the extraction main pipe 5.

[0057] The comprehensive monitoring module includes a multi-parameter collector 6, a data transmission pipeline 7, a data storage device, a logic reader, a clock timer and a signal transmitter; the multi-parameter collector 6 is connected to the extraction screen pipe 1 through the data transmission pipeline 7, and collects the gas temperature and humidity, gas and oxygen concentration parameters in the environment in real time, and transmits them to the data storage device through the optical fiber in the interlayer between the data transmission pipeline 7 and the extraction main pipe 5.

[0058] The data transmission line 7 is an optical fiber for data transmission. It is protected by a high-pressure steel wire braided hose within the goaf and, within the extraction system, is located within the interlayer of the extraction main pipe 5. The data storage device modulates and demodulates the received optical signal into a digital signal and stores it locally for access by the logic reader. The logic reader retrieves the stored gas parameters and comprehensively determines whether gas extraction is necessary. It generates a valve opening and closing command and sends it through a signal transmitter to the distributed extraction control module. A clock timer automatically counts and activates the logic reader at fixed intervals. The signal transmitter transmits commands issued by the logic reader or manually to the distributed extraction control module.

[0059] The distributed extraction control module includes a signal receiver, a signal processor, a pneumatic driver, a capsule valve 8 and a pneumatic bundle tube 9; the signal receiver receives the signal from the signal transmitter and transmits it to the signal processor; the signal processor converts the valve switch signal into a drive command and transmits it to the pneumatic driver; the pneumatic driver provides opening and closing power for the capsule valve 8 and controls the degree of opening and closing.

[0060] The capsule valve 8 is arranged in the pipeline tee 3 and is connected to the pneumatic driver through the pneumatic bundle tube 9. The capsule is expanded by inflation to block the pipeline tee 3 and close the corresponding extraction screen pipe 1. The pneumatic bundle tube 9 is arranged in the interlayer of the extraction main pipe 5 to provide power for the capsule valve 8.

[0061] The extraction device of the present invention organically integrates the gas extraction module, the comprehensive monitoring module and the distributed extraction control module to form a "monitoring-analysis-control" closed-loop system. Among them, the comprehensive monitoring module collects data such as gas concentration, oxygen content and temperature in real time through the multi-parameter collector 6, and automatically generates valve opening and closing instructions through the logic reader, so as to realize intelligent regulation of the extraction process and break through the lag limitation of traditional manual judgment of extraction effect. The extraction main pipe 5 adopts a double-layer PVC hollow tube design, and the optical fiber and pneumatic bundle tube 9 are integrated in the interlayer to realize signal transmission and power supply simultaneously, which significantly improves the system integration and reliability. Traditional extraction valves are ball valves or butterfly valves, which require manual operation and cannot be controlled in different zones. The present invention has a built-in three-way valve in the capsule valve 8, which is remotely controlled by pneumatics to solve the technical problem of accurate extraction of thick coal seams in the initial mining period.

[0062] The present invention also discloses a gas extraction method for a thick coal seam working face during the initial mining period, the method is based on the above-mentioned gas extraction device for a thick coal seam working face during the initial mining period; Figure 5 The extraction method specifically includes the following steps:

[0063] Step 1: Before mining, the working face is divided into different units along the dip according to the thickness of the coal seam, and the spacing of the gas extraction devices is determined for each unit.

[0064] The specific steps include:

[0065] Step 1.1: Before mining at the working face, establish a mathematical mapping relationship between coal seam thickness and the spacing between extraction devices using numerical simulation methods;

[0066] Specifically, a gas extraction module and initial mining goaf model were established using 3D modeling software. The model included different coal seam thicknesses and gas extraction module layout spacing. An experimental scheme was designed using the orthogonal test method. The experimental schemes were calculated, and the gas concentration and gas extraction volume in the goaf under each experimental scheme were statistically analyzed to determine the range of gas extraction module layout spacing that achieved the best extraction results under different coal seam thicknesses.

[0067] Step 1.2: Divide the cut into different extraction units according to the change in coal seam thickness at the cut, and determine the layout spacing of the gas extraction modules for each extraction unit.

[0068] Step 2: Extend the extraction pipeline from the return air lane of the working face to the cutting position, and lead the line outward along the air inlet lane at the air inlet side interface of the gas extraction module, and install the monitoring host 10 of the comprehensive monitoring module and the control host 11 of the distributed extraction control module in the air inlet lane.

[0069] The specific steps include:

[0070] Step 2.1: Install the main valve 13 on the extraction main pipe 12 of the return air lane of the working face, connect the gas extraction module to the side of the air intake lane, and place the gas extraction module on the wall of the cut hole away from the working face;

[0071] Step 2.2: Lead out the interlayer pipeline from the pipe mouth of the gas extraction module's extraction main pipe 5 and install the monitoring host 10 at a suitable position in the air inlet tunnel; the monitoring host 10 is composed of a clock timer, data storage device, logic analyzer and signal transmitter in the integrated monitoring module.

[0072] Step 2.3: Install the control host 11 at the same location as step 2.2 above. The control host 11 consists of a signal receiver, a signal processor, and a pneumatic driver in the distributed extraction control module; the pneumatic driver is connected to the pneumatic bundle tube 9 in the interlayer of the extraction main pipe 5.

[0073] Step 3: Install the gas extraction module and supporting pipelines along the roadway at the determined intervals in the cut hole. Fix the gas extraction module close to the wall and install a protective shell on the outside.

[0074] The specific steps include:

[0075] Step 3.1: Install the gas drainage module's drainage main pipe 5 at one end of the distributed drainage control module. Place the main pipe 5 close to the wall away from the mining face on the cut hole. Use wire or other means to hang and secure it to the wall anchor net at a height of no less than 2m.

[0076] Step 3.2: Install the pipe tees 3 on the main drainage pipe 5 in sequence, based on the determined spacing of the gas drainage modules. The openings of the pipe tees 3 hang naturally downward. The first pipe tee 3 is installed starting from the mining side wall of the intake airway, and the last pipe tee 3 ends at the mining side of the return airway.

[0077] Step 3.3: Connect the pipe tee 3 downward to the screen valve 2 and the extraction screen 1. Install the extraction plug 4 at the end of the extraction screen 1. The height of the lower end of the screen should be no less than 0.5m from the ground.

[0078] Step 3.4: Install a metal protective scaffolding on the top of the gas extraction module. The outer width of the scaffolding should be greater than the width of the gas extraction module to prevent the gas extraction module from being damaged by falling rocks. Step 3 specifically includes the following steps:

[0079] Step 3.1: Install the gas drainage module's drainage main pipe 5 at one end of the distributed drainage control module. Place the main pipe 5 close to the wall away from the mining face on the cut hole. Use wire or other means to hang and secure it to the wall anchor net at a height of no less than 2m.

[0080] Step 3.2: Install the pipe tees 3 on the main drainage pipe 5 in sequence, based on the determined spacing of the gas drainage modules. The openings of the pipe tees 3 hang naturally downward. The first pipe tee 3 is installed starting from the mining side wall of the intake airway, and the last pipe tee 3 ends at the mining side of the return airway.

[0081] Step 3.3: Connect the pipe tee 3 downward to the screen valve 2 and the extraction screen 1. Install the extraction plug 4 at the end of the extraction screen 1. The height of the lower end of the screen should be no less than 0.5m from the ground.

[0082] Step 3.4: Install a metal protective scaffolding on the top of the gas extraction module. The outer edge width of the scaffolding should be greater than the width of the gas extraction module to prevent the gas extraction module from being damaged by falling rocks.

[0083] Step 4: Install the multi-parameter collector 6 of the comprehensive monitoring module and the capsule valve 8 of the distributed extraction control module at the corresponding positions of the extraction screen 1 and the pipeline tee 3.

[0084] The specific steps include:

[0085] Step 4.1: Connect the multi-parameter collector 6 to the lower end of the extraction screen 1 and number it 1#. Connect the data transmission fiber to the interlayer of the extraction main pipe 5. Pre-connect the other end to the 5-10m data transmission pipeline 7, extending from the bracket gap to the working surface. Use the extraction plug 4 to protect the end.

[0086] Step 4.2: After the working face begins to recover, remove the extraction plug 4 at the end of the data transmission pipeline 7 and install the second multi-parameter collector 6, numbered 2#. Pre-connect a 5-10m data transmission pipeline 7 to the other end of the multi-parameter collector 6. As the working face advances, continue to connect multi-parameter collectors 6 and number them in sequence.

[0087] Step 4.3: Install the capsule valve 8 in the distributed extraction control module inside the pipeline tee 3 and connect it to the pneumatic bundle pipe 9 in the interlayer of the extraction main pipe 5. The capsule valve 8 is not inflated by default and remains open.

[0088] Furthermore, the multi-parameter collectors 6 are arranged in a group at intervals of 30-40 m along the cutting direction, and are installed on the nearest extraction screen pipe 1 .

[0089] Step 5: Before the working face starts mining, open the return air side screen valve 2 and close the air inlet side screen valve 2, giving priority to gas extraction at the cut eye; after the working face advances, open the air inlet side extraction screen 1 valve to fully extract the cut eye; after the working face starts mining, open the comprehensive monitoring module simultaneously, collect oxygen, carbon monoxide and other data in the goaf through the comprehensive monitoring module, and judge whether the residual coal is oxidized based on the carbon monoxide concentration. If the carbon monoxide concentration continues to rise, close the extraction screen 1 at the corresponding position; when the basic roof collapses completely, that is, after the initial mining period is completed, close the extraction main pipe 5, stop gas extraction in the cut eye area, and prevent air leakage from causing spontaneous combustion of the residual coal.

[0090] The specific steps include:

[0091] Step 5.1: Divide all extraction screens 1 into two along the cut direction, with one half being the air intake side extraction screen 1 and the other half being the return air side extraction screen 1. Close the capsule valves 8 corresponding to the air intake side extraction screen 1 by injecting air, leaving only the return air side extraction screen 1. When the working face begins extraction, open the main valve 13 of the extraction main pipe 12, prioritizing negative pressure extraction on the return air side. This prevents airflow short-circuiting caused by extraction from the air intake side screen.

[0092] Step 5.2: When the working face is 5m away from the mining, the wall is sealed at the construction end on the air inlet side to prevent airflow short-circuiting caused by extraction on the air inlet side. The capsule valve 8 is deflated through the distributed extraction control module, the air inlet side extraction screen 1 is opened, and extraction is carried out in the entire cut-hole area.

[0093] Among them, the end sealing wall can be formed by piling up yellow mud sandbags, perlite and other materials, and colloidal foam is injected behind the wall to seal the gaps.

[0094] Step 5.3: After a large area of ​​top coal collapse occurs, turn on the integrated monitoring module and read the gas parameters of the multi-parameter collector 6 every 30 minutes to determine the oxygen and gas concentrations in the goaf. This will prevent oxidation of the coal caused by air entering the goaf. If carbon monoxide is present and its concentration continues to rise, close the extraction screen 1 within 20 meters on both sides of the monitoring point.

[0095] Step 5.4: After the extraction stops, the extraction parameters are continuously monitored and the gas parameters of the multi-parameter collector 6 are read every 30 minutes. When the gas concentration is greater than the extraction start threshold and the carbon monoxide concentration no longer increases, the sieve valve 2 of the corresponding extraction sieve 1 is controlled to open and gas extraction is resumed. If the opening conditions are not met, wait for another 30 minutes and interpret the data.

[0096] The threshold for starting extraction is determined based on the airflow gas concentration limit specified by national standards, industry specifications or local policies, or comprehensively determined based on the mine gas conditions.

[0097] Step 5.5: After the initial pressure buildup on the basic roof is complete, close the main extraction pipe 5 and stop extracting gas from the cut-eye area to prevent large-scale air leakage from causing spontaneous combustion of the remaining coal.

[0098] The proposed extraction method uses 3D modeling and orthogonal testing to establish a mapping model between coal seam thickness and extraction module spacing, enabling differentiated extraction device placement. By dividing extraction units based on the thickness of the cut seam, and independently determining the spacing between each unit, extraction efficiency is increased by over 30% compared to traditional fixed-spacing arrangements.

[0099] During the initial mining phase, the return air screen valve 2 is opened first. Once the working face advances, the inlet air side is opened, and the end capping wall is used to prevent airflow short-circuiting. This strategy dynamically couples the extraction process with the working face advancement phase for the first time, effectively resolving the gas over-limit issue caused by ventilation system instability during the initial mining phase.

[0100] By monitoring carbon monoxide concentrations to determine the oxidation state of the residual coal, the system automatically closes the corresponding extraction screen 1 when the concentration continues to rise, preventing air leakage from exacerbating the risk of spontaneous combustion. This design, which integrates gas extraction with spontaneous combustion prevention, fills a gap in traditional technologies for complex disaster prevention and control.

[0101] The distributed extraction control module controls the capsule valve 8 through the pneumatic bundle tube 9, which can independently close a single extraction screen tube 1, realizing the refined management of "local extraction-global regulation". Compared with the traditional valve group control method, the extraction parameter adjustment response time is shortened from 30 minutes to 5 minutes.

[0102] To address the delayed roof collapse and underdeveloped fracture zones during the initial mining phase, extraction modules are placed directly within the cut. Negative pressure extraction creates a negative pressure zone within the cut, drawing fresh air deeper into the goaf. This addresses the ineffectiveness of traditional methods, such as high-level drilling, during the initial mining phase. Multi-parameter collectors are gradually deployed as the working face advances, ensuring continuous gas monitoring in the goaf and enabling comprehensive gas prevention and control throughout the entire process, from cut opening to primary roof collapse.

[0103] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A gas extraction device for the initial mining period of a thick coal seam working face, characterized by: Includes comprehensive monitoring module, distributed extraction control module and gas extraction module; The gas extraction module comprises an extraction screen (1), a screen valve (2), a pipeline tee (3), an extraction plug (4) and an extraction main pipe (5); the screen valve (2) is installed between the upper end opening of the extraction screen (1) and the pipeline tee (3); the screen valve (2) is used to control the extraction area and the extraction force during the installation of the extraction equipment; the pipeline tee (3) connects the screen valve (2) to the extraction main pipe (5); the extraction plug (4) is installed on the extraction screen The lower end opening of the extraction screen (1) is used to connect the integrated monitoring module and block the lower end outlet of the extraction screen (1); the extraction main pipe (5) is a double-layer PVC hollow pipe, and optical fibers and pneumatic bundle pipes (9) are arranged in the interlayer of the extraction main pipe (5) and are connected to the distributed extraction control module. One end of the extraction main pipe (5) is connected to the extraction main pipe (12), and the gas extracted by the extraction screen (1) is transported to the extraction main pipe (12) of the mine gas through the hollow pipeline of the extraction main pipe (5); The comprehensive monitoring module includes a multi-parameter collector (6), a data transmission pipeline (7), a data storage, a logic reader, a clock timer and a signal transmitter; the multi-parameter collector (6) is connected to the extraction screen (1) through the data transmission pipeline (7), collects the gas temperature and humidity, gas and oxygen concentration parameters in the environment in real time, and transmits them to the data storage through the data transmission pipeline (7) and the optical fiber in the interlayer of the extraction main pipe (5); the data transmission pipeline (7) is an optical fiber for data transmission, which is arranged in the interlayer of the extraction main pipe (5); the data storage modulates and demodulates the received optical signal into a digital signal and stores it in a local space for the logic reader to read and use; the logic reader retrieves the stored gas parameters and comprehensively determines whether gas extraction is required, generates a valve opening and closing command, and sends a signal to the distributed extraction control module through the signal transmitter; the clock timer automatically counts and activates the logic reader at fixed intervals; the signal transmitter transmits the instructions issued by the logic reader or manually to the distributed extraction control module; The distributed extraction control module includes a signal receiver, a signal processor, a pneumatic driver, a capsule valve (8) and a pneumatic bundle tube (9); the signal receiver receives a signal from a signal transmitter and transmits it to the signal processor; the signal processor converts the valve switch signal into a drive command and transmits it to the pneumatic driver; the pneumatic driver provides opening and closing power for the capsule valve (8) and controls the opening and closing degree; the capsule valve (8) is arranged in a pipeline tee (3) and is connected to the pneumatic driver through a pneumatic bundle tube (9); the capsule is expanded by inflation control, and the pipeline tee (3) is blocked, thereby closing the corresponding extraction screen tube (1); the pneumatic bundle tube (9) is arranged in the interlayer of the extraction main pipe (5) and provides power for the capsule valve (8).

2. A gas extraction method during the initial mining period of a thick coal seam working face, characterized by: The gas extraction device during the initial mining period of a thick coal seam working face according to claim 1 is used; the gas extraction method comprises the following steps: Step 1: Before mining, the working face is divided into different units along the dip according to the thickness of the coal seam, and the spacing of the gas extraction devices is determined for each unit; Step 2: Extend the extraction pipeline from the return air lane of the working face to the cut-eye position, and lead the line outward along the air inlet lane at the air inlet side interface of the gas extraction module, and install the monitoring host (10) of the comprehensive monitoring module and the control host (11) of the distributed extraction control module in the air inlet lane; Step 3: Install the gas extraction module and supporting pipelines along the roadway at the spacing determined in Step 1. Fix the gas extraction module close to the wall and install a protective shell on the outside. Step 4: Install the multi-parameter collector (6) of the integrated monitoring module and the capsule valve (8) of the distributed extraction control module at the corresponding positions of the extraction screen (1) and the pipeline tee (3); Step 5: Before the working face starts to be mined, open the return air side screen valve (2) and close the air intake side screen valve (2), and give priority to gas extraction at the cut eye; after the working face advances, open the air intake side extraction screen valve (1) and conduct comprehensive extraction of the cut eye; after the working face starts to be mined, open the comprehensive monitoring module simultaneously, collect oxygen and carbon monoxide data in the goaf through the comprehensive monitoring module, and judge whether the residual coal is oxidized based on the carbon monoxide concentration. If the carbon monoxide concentration continues to rise, close the extraction screen (1) at the corresponding position; when the basic roof is completely collapsed, that is, after the initial mining period is completed, close the extraction main pipe (5), stop gas extraction in the cut eye area, and prevent air leakage from causing spontaneous combustion of the residual coal.

3. The method for gas extraction during initial mining of a thick coal seam working face according to claim 1, characterized in that: The step 1 specifically includes the following steps: Step 1.1: Before mining at the working face, establish a mathematical mapping relationship between coal seam thickness and the spacing between extraction devices using numerical simulation methods; Step 1.2: Divide the cut into different extraction units according to the change in coal seam thickness at the cut, and determine the layout spacing of the gas extraction modules for each extraction unit.

4. The method for gas extraction during initial mining of a thick coal seam working face according to claim 1, characterized in that: The step 2 specifically includes the following steps: Step 2.1: Install the main valve (13) on the extraction main pipe (12) of the return air lane of the working face, connect the gas extraction module to the side of the air intake lane, and arrange the gas extraction module on the wall of the cut hole away from the working face; Step 2.2: Lead the interlayer pipeline from the pipe mouth of the gas extraction main pipe (5) of the gas extraction module to the appropriate position of the air inlet tunnel to install the monitoring host (10); the monitoring host (10) is composed of the clock timer, data storage, logic reader and signal transmitter in the integrated monitoring module; Step 2.3: Install a control host (11) at the same location as in step 2.2 above. The control host (11) is composed of a signal receiver, a signal processor, and a pneumatic driver in the distributed extraction control module; the pneumatic driver is connected to the pneumatic bundle tube (9) in the interlayer of the extraction main pipe (5).

5. The method for gas extraction during initial mining of a thick coal seam working face according to claim 1, characterized in that: The step 3 specifically includes the following steps: Step 3.1: Install the drainage main pipe (5) of the gas drainage module at one end of the distributed drainage control module. The drainage main pipe (5) is close to the wall of the cut hole away from the mining face, and is hung and fixed on the wall anchor net. The hanging height is not less than 2m. Step 3.2: According to the determined arrangement spacing of the gas extraction modules, the pipeline tees (3) are installed on the extraction main pipe (5) in sequence, with the openings of the pipeline tees (3) hanging naturally downward. The first pipeline tee (3) is arranged starting from the mining side wall of the air inlet lane, and the last pipeline tee (3) ends at the mining side of the return air lane; Step 3.3: Connect the pipe tee (3) downward to the screen valve (2) and the extraction screen (1), install the extraction plug (4) at the end of the extraction screen (1), and ensure that the lower end of the extraction screen (1) is at least 0.5m above the ground; Step 3.4: Install a metal protective scaffolding on the top of the gas drainage module. The outer width of the scaffolding should be greater than the width of the gas drainage module.

6. The method for gas extraction during initial mining of a thick coal seam working face according to claim 1, characterized in that: Step 4 specifically includes the following steps: Step 4.1: Connect the multi-parameter collector (6) to the lower end of the extraction screen (1) and number it 1#. Connect the data transmission optical fiber to the interlayer of the extraction main pipe (5). Pre-connect the other end with a 5-10m data transmission pipeline (7), extending from the bracket gap to the working surface, and use the extraction plug (4) to protect the end; Step 4.2: After the working face begins to recover, remove the extraction plug (4) at the end of the data transmission pipeline (7) and install the second multi-parameter collector (6), which is numbered as 2#. Pre-connect a 5-10m data transmission pipeline (7) at the other end of the multi-parameter collector (6). As the working face advances, continue to connect the multi-parameter collectors (6) and number them in sequence. Step 4.3: Install the capsule valve (8) in the distributed extraction control module inside the pipeline tee (3) and connect it to the pneumatic bundle pipe (9) in the interlayer of the extraction main pipe (5). The capsule valve (8) is not inflated by default and remains in the open state.

7. A gas extraction method during initial mining in a thick coal seam working face according to claim 6, characterized in that: The multi-parameter collectors (6) are arranged in a group at intervals of 30-40 m along the cutting direction, and are installed on the nearest extraction screen pipe (1).

8. The method for gas extraction during initial mining of a thick coal seam working face according to claim 1, characterized in that: Step 5 specifically includes the following steps: Step 5.1: Divide all the extraction screens (1) into two along the cutting direction, one half is the air intake side extraction screen (1), and the other half is the return air side extraction screen (1). Close the capsule valve (8) corresponding to the air intake side extraction screen (1) by air injection, and only retain the return air side extraction screen (1). When the working face starts to recover, open the main valve (13) of the extraction main pipe (12), give priority to the return air side negative pressure extraction, and prevent the air intake side screen pipe from causing airflow short circuit; Step 5.2: When the working face is mined at a distance of 5m, the wall is sealed at the construction end of the air inlet side to prevent airflow short-circuiting caused by extraction on the air inlet side, and the capsule valve (8) is deflated through the distributed extraction control module, the extraction screen (1) on the air inlet side is opened, and the entire cut-eye area is extracted; Step 5.3: After a large area of ​​top coal collapse occurs, turn on the integrated monitoring module and read the gas parameters of the multi-parameter collector (6) every 30 minutes to determine the oxygen and gas concentrations in the goaf. This will prevent the oxidation of the coal caused by air entering the goaf. If carbon monoxide appears and its concentration continues to rise, close the extraction screens (1) within 20 meters on both sides of the monitoring point. Step 5.4: After the extraction is stopped, the extraction parameters are continuously monitored and the gas parameters of the multi-parameter collector (6) are read every 30 minutes. When the gas concentration is greater than the extraction start threshold and the carbon monoxide concentration no longer increases, the sieve valve (2) of the corresponding extraction sieve (1) is controlled to open and gas extraction is resumed. If the opening conditions are not met, wait for another 30 minutes and read the data; Step 5.5: After the initial pressure buildup on the basic roof is complete, close the main extraction pipe (5) and stop extracting gas from the cut-eye area to prevent large-scale air leakage from causing spontaneous combustion of the remaining coal.

9. A gas extraction method during initial mining in a thick coal seam working face according to claim 8, characterized in that: In step 5.2, the end blocking wall is formed by stacking yellow mud sand bags and perlite materials, and colloidal foam is injected behind the wall to block the gap to prevent airflow short-circuiting caused by extraction on the air inlet side.

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