Coordinated mining method for close coal seams

Abstract

The present invention discloses a method for coordinated mining of close coal seams, including: roadway design of the upper coal seam and the lower coal seam, the mining sequence of the upper coal seam and the lower coal seam, and the roadway support method and roof management method for gob-side entry retaining. By designing different mining directions in the upper and lower coal seams and matching the roadway layout with inner or outer stagger in the upper and lower coal seams, the present invention realizes coordinated mining of close coal seams with the upper coal seam shortening the driving length, reducing the number of open-off cuts, and no reserved coal pillars in the upper and lower coal seams.

Description

Technical Field

[0001] The present invention relates to the field of coal seam mining. More specifically, the present invention relates to a method for coordinated mining of close coal seams. Background Art

[0002] With the long-term high-intensity mining of coal resources in the eastern part of China, the coal resources in the eastern region have gradually faced exhaustion, and the focus of coal resource development has gradually shifted to the western region. The coal resources in the western mining area are buried relatively shallowly, occur in multiple coal seams, and there are significant differences in coal quality between coal seams. It is necessary to carry out combined mining of multiple coal seams to maximize the economic benefits of the mining area. Affected by geological conditions and other factors, some mines often adopt the single-wing mining method to mine the coal resources in the mine field, resulting in problems such as low mining and excavation replacement efficiency and serious influence of the working face by mining activities, which seriously restrict the production efficiency of the mine and affect the safe production of the coal mine.

[0003] Currently, in response to such problems, a method for coordinated mining of upper and lower close coal seams in sequence is disclosed in the invention patent with the application number 201910302735.2. In this method, the main mining coal seam and the associated mining coal seam are determined according to the coal quality conditions and market demands. The first mining face transportation roadway and the return air roadway are driven along the floor of the main mining coal seam. At the same time, the associated mining face return roadway is arranged in the stress reduction area of the associated mining coal seam. When the main mining face has been mined for a certain distance, the associated mining face is mined, and the above mining sequence is repeated until the close coal seams are mined out. However, it can be seen from the drawings of the above method that after the A1 working face of the main mining coal seam is mined, it is necessary to advance the upper and lower gateways of the A2 working face in advance, and then open the cutting eye of the A2 working face. Therefore, the driving length is long and the cutting eye opening process is multiple. In addition, it is not difficult to see from the figure that coal pillars are left between adjacent mining areas of the same coal seam, and the resources cannot be fully exploited. Summary of the Invention

[0004] The object of the present invention is to provide a method for coordinated mining of close coal seams, which realizes the coordinated mining of close coal seams with shortened driving length of the upper coal seam, reduced number of cutting eye openings, and no reserved coal pillars between the upper and lower coal seams by designing different mining directions in the upper and lower coal seams and matching the layout of inner-offset or outer-offset roadways in the upper and lower coal seams.

[0005] To achieve these and other advantages in accordance with the present invention, there is provided a method for coordinated mining of close coal seams, which comprises:

[0006] The first transport roadway and the first track roadway are arranged along the upper coal seam or its roof and floor. In the upper coal seam, a upper transport crossheading communicating with the first transport roadway is driven, and a upper track crossheading communicating with the first track roadway is driven. An upper cutting eye is driven between the upper transport crossheading and the upper track crossheading to connect the upper transport crossheading and the upper track crossheading. The upper cutting eye is close to the ends of the upper transport crossheading and the upper track crossheading, so as to form a small mining area of the upper coal seam on one side of the upper cutting eye and a large mining area of the upper coal seam on the other side. Support is set in the upper cutting eye to form a mining roadway for the upper coal seam.

[0007] The second transport roadway and the second track roadway are arranged along the lower coal seam or its roof and floor. On one side of the boundary of the lower coal seam, a coal haulage rise of the lower coal seam communicating with the second transport roadway is driven, and a track rise of the lower coal seam communicating with the second track roadway is driven. The roadway of the track rise of the lower coal seam is deeper than that of the coal haulage rise of the lower coal seam. The roadway trends of the coal haulage rise of the lower coal seam and the track rise of the lower coal seam are the same as those of the upper transport crossheading and the upper track crossheading. At the end of the coal haulage rise of the lower coal seam, a first lower transport crossheading is driven. The head of the first lower transport crossheading is communicated with the roadway of the track rise of the lower coal seam. At the end of the track rise of the lower coal seam, a first lower track crossheading is driven. The roadway trends of the first lower transport crossheading and the first lower track crossheading are the same as those of the upper cutting eye. The first lower transport crossheading is arranged staggeredly with the upper cutting eye. A first lower cutting eye is driven between the first lower transport crossheading and the first lower track crossheading. The roadway trend of the first lower cutting eye is perpendicular to that of the upper cutting eye and the first lower cutting eye is arranged staggeredly with the upper transport crossheading. The first lower cutting eye is close to the ends of the first lower transport crossheading and the first lower track crossheading, so as to form a first small mining area of the lower coal seam on one side of the first lower cutting eye and a first large mining area of the lower coal seam on the other side. Support is set in the first lower cutting eye to form a mining roadway for the first lower coal seam.

[0008] Preferably, the coordinated mining method for close-distance coal seams further includes:

[0009] The large mining area of the upper coal seam is mined, and at the same time, the first small mining area of the lower coal seam is mined. The gob-side entry retaining is carried out for the mining roadway of the upper coal seam and the mining roadway of the first lower coal seam. When the first small mining area of the lower coal seam is mined out, the direct caving treatment method is adopted for the roof of the first small mining area of the lower coal seam.

[0010] When the gob area of the large mining area of the upper coal seam crosses the first lower transport crossheading, the small mining area of the upper coal seam begins to be mined, and at the same time, the mining of the large mining area of the upper coal seam continues until both the large mining area of the upper coal seam and the small mining area of the upper coal seam are mined out, and then the direct caving treatment method is adopted for the roof of the upper coal seam.

[0011] The first lower coal seam large mining area is mined until the first lower coal seam large mining area is mined out, and the first lower transport drift is left along the goaf, and then the first lower coal seam small mining area roof, the first lower coal seam large mining area roof, the first lower coal seam mining roadway roof and the first lower track drift roof are directly collapsed;

[0012] A second lower transport drift is excavated in the middle of the tunnel for transporting coal uphill in the lower coal seam. The tunnel direction of the second lower transport drift is the same as that of the first lower transport drift. The first lower transport drift is used as the second lower track drift. A second lower cut is excavated between the second lower track drift and the end of the second lower transport drift to form a working face of the second lower coal seam mining area adjacent to the first lower coal seam small mining area and the first lower coal seam large mining area;

[0013] The second lower coal seam mining area is mined until the second lower coal seam mining area is mined out.

[0014] Preferably, the offset between the upper cutting eye and the first lower transport chute is 10 meters, and the offset between the first lower cutting eye and the upper transport chute is 8 meters.

[0015] Preferably, the small mining area of ​​the upper coal seam and the small mining area of ​​the first lower coal seam are mined by blasting or general mining, and the large mining area of ​​the upper coal seam, the large mining area of ​​the first lower coal seam and the second lower coal seam mining area are mined by comprehensive mining.

[0016] Preferably, a hydraulic support is used for support on one side of the upper cutting eye close to a small mining area of ​​the upper coal seam, and a fully mechanized mining equipment is used for support on one side of the upper cutting eye close to a large mining area of ​​the upper coal seam.

[0017] Preferably, the method of retaining a lane along the goaf in the upper coal seam mining tunnel includes: as the mining face of the large mining area of ​​the upper coal seam advances forward, a wall support is constructed behind the comprehensive mining equipment in the large mining area of ​​the upper coal seam, thereby forming a lane along the goaf together with the hydraulic support support on one side of the upper cutting eye close to the small mining area of ​​the upper coal seam.

[0018] Preferably, a hydraulic support is used for support on one side of the first lower cutting eye close to a small mining area of ​​the first lower coal seam, and a fully mechanized mining equipment is used for support on one side of the first lower cutting eye close to a large mining area of ​​the first lower coal seam.

[0019] Preferably, the method for retaining a lane along the goaf in the first lower coal seam mining tunnel includes: as the mining face of the small mining area of ​​the first lower coal seam advances forward, a wall support is constructed behind the hydraulic support support of the small mining area of ​​the first lower coal seam, thereby forming a lane along the goaf together with the support provided by the comprehensive mining equipment on one side of the first lower coal seam near the large mining area of ​​the first lower coal seam in the first lower cutting eye.

[0020] Preferably, the wall support is a sandwich wall built with high-water materials. A plastic film is attached to the outer wall of the sandwich wall to prevent it from contacting the air. A ventilation pipe is provided in the sandwich wall. The pipe wall of the ventilation pipe is evenly spaced with air holes. When it is necessary to collapse the roof of the goaf, carbon dioxide is introduced into the ventilation pipe to carbonize and decompose the high-water materials, thereby releasing the support for the roof of the goaf and allowing the roof of the goaf to collapse naturally.

[0021] The present invention has at least the following beneficial effects: For the upper coal seam, only one cut-eye needs to be opened to complete the coal mining task of the entire coal seam. Therefore, it is not necessary to repeatedly drive the transportation gateway and the track gateway in the upper coal seam, which greatly shortens the gateway driving length of the upper coal seam. At the same time, the large mining area of the upper coal seam is not divided, so the fully mechanized mining method can be used to mine to the bottom, and the coal mining continuity is good. In addition, while the upper coal seam is being mined, the small mining area of the first lower coal seam is also mined, and the large and small mining areas of the upper coal seam are mined simultaneously, so the coal mining efficiency is improved. Moreover, the overlapping area between the small mining area of the first lower coal seam and the small mining area of the upper coal seam is small. Therefore, by first mining the small mining area of the first lower coal seam and then mining the small mining area of the upper coal seam in an upward mining method, the influence on the overlying strata of the small mining area of the upper coal seam is small, and it is also convenient to evacuate the groundwater and gas in the small mining area of the upper coal seam. Furthermore, by adopting the method of roof collapse treatment in the goaf of each coal seam, the stress of the overlying strata of each coal seam is released, so there is no need to set coal pillars, and the coal seam can be mined to the greatest extent.

[0022] Other advantages, objectives and features of the present invention will be partially reflected by the following description, and partially will be understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the gateway driving of the upper coal seam and the lower coal seam and the simultaneous coal mining of the large mining area of the upper coal seam and the small mining area of the first lower coal seam in the close-distance coal seam coordinated mining method described in the embodiment of the present invention;

[0024] Figure 2 It is a schematic diagram of the simultaneous coal mining of the large mining area of the upper coal seam and the small mining area of the upper coal seam in the close-distance coal seam coordinated mining method described in the embodiment of the present invention;

[0025] Figure 3 It is a schematic diagram of the coal mining of the large mining area of the first lower coal seam in the close-distance coal seam coordinated mining method described in the embodiment of the present invention;

[0026] Figure 4 It is a schematic diagram of the coal mining of the mining area of the second lower coal seam in the close-distance coal seam coordinated mining method described in the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] The following further describes the present invention in detail with reference to the drawings, so that those skilled in the art can implement it according to the description in the specification.

[0028] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials, unless otherwise specified, can all be obtained from commercial channels; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention 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 construed as a limitation on the present invention.

[0029] The present invention provides a method for coordinated mining of close coal seams, which includes:

[0030] As Figure 1 shown, a first transport roadway 1 and a first track roadway 2 are arranged along the upper coal seam or its roof and floor. In the upper coal seam, an upper transport crossheading 3 communicating with the first transport roadway 1 is driven, and an upper track crossheading 4 communicating with the first track roadway 2 is driven. An upper cutting eye 5 is driven between the upper transport crossheading 3 and the upper track crossheading 4 to connect the upper transport crossheading 3 and the upper track crossheading 4. The upper cutting eye 5 is close to the ends of the upper transport crossheading 3 and the upper track crossheading 4, so as to form a small mining area 6 of the upper coal seam on one side of the upper cutting eye 5 and a large mining area 7 of the upper coal seam on the other side. Support is set in the upper cutting eye 5 to form a mining roadway of the upper coal seam;

[0031] A second transport roadway 8 and a second track roadway 9 are arranged along the lower coal seam or its roof and floor. A coal haulage rise 10 of the lower coal seam communicating with the second transport roadway 8 and a track rise 11 of the lower coal seam communicating with the second track roadway 9 are driven on one side of the lower coal seam boundary. The roadway of the track rise 11 of the lower coal seam is deeper than that of the coal haulage rise 10 of the lower coal seam. The roadway trends of the coal haulage rise 10 of the lower coal seam and the track rise 11 of the lower coal seam are the same as those of the upper transport crossheading 3 and the upper track crossheading 4. A first lower transport crossheading 12 is driven at the end of the coal haulage rise 10 of the lower coal seam. The head of the first lower transport crossheading 12 is connected to the roadway of the track rise 11 of the lower coal seam. A first lower track crossheading 13 is driven at the end of the track rise 11 of the lower coal seam. The roadway trends of the first lower transport crossheading 12 and the first lower track crossheading 13 are the same as those of the upper cutting eye 5. The first lower transport crossheading 12 is arranged staggeredly with the upper cutting eye 5. A first lower cutting eye is driven between the first lower transport crossheading 12 and the first lower track crossheading 13. The roadway trend of the first lower cutting eye is perpendicular to that of the upper cutting eye 5 and the first lower cutting eye is staggered with the upper transport crossheading 3. The first lower cutting eye is close to the ends of the first lower transport crossheading 12 and the first lower track crossheading 13, so as to form a first small mining area 15 of the lower coal seam on one side of the first lower cutting eye and a first large mining area 16 of the lower coal seam on the other side. Support is set in the first lower cutting eye to form a mining roadway of the first lower coal seam;

[0032] The upper coal seam large mining area 7 is mined, and at the same time, the first lower coal seam small mining area 15 is mined. The gob-side entry retaining is carried out for the mining roadway of the upper coal seam and the mining roadway of the first lower coal seam. When the first lower coal seam small mining area 15 is mined out, the roof of the first lower coal seam small mining area 15 is directly caved;

[0033] As Figure 2 and Figure 3 shown, when the gob area of the upper coal seam large mining area 7 crosses the first lower haulage gateway 12, the upper coal seam small mining area 6 is started to be mined, and at the same time, the mining of the upper coal seam large mining area 7 continues until both the upper coal seam large mining area 7 and the upper coal seam small mining area 6 are mined out, and then the roof of the upper coal seam is directly caved;

[0034] The first lower coal seam large mining area 16 is mined until the first lower coal seam large mining area 16 is mined out. The gob-side entry retaining is carried out for the first lower haulage gateway 12, and then the roofs of the first lower coal seam small mining area 15, the first lower coal seam large mining area 16, the roof of the first lower coal seam mining roadway and the roof of the first lower track gateway 13 are directly caved;

[0035] As Figure 4 shown, the second lower haulage gateway 17 is driven in the middle of the roadway of the lower coal seam haulage rise 10. The roadway direction of the second lower haulage gateway 17 is the same as that of the first lower haulage gateway 12. The first lower haulage gateway 12 is used as the second lower track gateway. The second lower cutting eye 18 is driven between the ends of the second lower track gateway and the second lower haulage gateway 17 to form a working face of the second lower coal seam mining area 19 adjacent to the first lower coal seam small mining area 15 and the first lower coal seam large mining area 16;

[0036] The second lower coal seam mining area 19 is mined until the second lower coal seam mining area 19 is mined out.

[0037] In the above embodiments, a one-in-one-out ventilation system is adopted. The air flow direction in the upper coal seam is: the first haulage roadway 1 → the upper haulage gateway 3 → the upper cutting eye 5 → the lower track gateway → the first track roadway 2. The fresh air flow direction in the lower coal seam is: the second haulage roadway 8 → the lower coal seam haulage rise 10 → the first lower haulage gateway 12 → the first lower cutting eye → the first lower track gateway 13 → the lower coal seam track rise 11 → the second track roadway 9, and the second haulage roadway 8 → the lower coal seam haulage rise 10 → the second lower haulage gateway 17 → the second lower cutting eye 18 → the second lower track gateway → the lower coal seam track rise 11 → the second track roadway 9.

[0038] The transportation process of raw coal in the above embodiments includes: For the raw coal in the upper coal seam, the transportation process is: upper cutting roadway 5 → upper transportation gateway 3 → first transportation roadway 1. For the raw coal in the lower coal seam, the transportation process is: first lower cutting roadway → first lower transportation gateway 12 → lower coal seam coal transportation rise 10 → second transportation roadway 8, and second lower cutting roadway 18 → second lower transportation gateway 17 → lower coal seam coal transportation rise 10 → second transportation roadway 8.

[0039] In the upper coal seam, underground workers in the mine enter the upper cutting roadway 5 along the first track roadway 2 and the upper track gateway 4 for work. In the lower coal seam, underground workers in the mine enter the first lower cutting roadway along the second track roadway 9, the lower coal seam track rise 11, and the first lower track gateway 13 for work, and enter the second lower cutting roadway 18 along the second track roadway 9, the lower coal seam track rise 11, and the second lower track gateway for work.

[0040] In the above embodiments, since only one cutting roadway needs to be opened in the upper coal seam to complete the coal mining task of the entire coal seam, there is no need to repeatedly drive the transportation gateway and the track gateway in the upper coal seam, greatly shortening the roadway driving length in the upper coal seam. At the same time, the large mining area 7 in the upper coal seam is not divided, so the fully mechanized mining method can be used to mine to the bottom in one go, and the coal mining continuity is good. In addition, while the upper coal seam is being mined, the first lower coal seam small mining area 15 is also mined, and there is also a simultaneous mining period between the small and large mining areas in the upper coal seam, so the coal mining efficiency is improved. Moreover, the overlapping area between the first lower coal seam small mining area 15 and the upper coal seam small mining area 6 is small, so mining the first lower coal seam small mining area 15 first and then mining the upper coal seam small mining area 6 by upward mining has little impact on the overlying rock of the upper coal seam small mining area 6, and it is also convenient to evacuate the groundwater and gas in the upper coal seam small mining area 6. Furthermore, the method of roof caving is adopted in the goaf of each coal seam to release the stress of the overlying rock of each coal seam, so there is no need to set coal pillars, and the coal seam can be mined to the greatest extent.

[0041] In a preferred embodiment of the above embodiments, the stagger distance between the upper cutting roadway 5 and the first lower transportation gateway 12 is 10 meters, and the stagger distance between the first lower cutting roadway and the upper transportation gateway 3 is 8 meters. The setting of the stagger distance comprehensively considers the change of the mine pressure of the floor of the upper coal seam (which is also the roof of the lower coal seam), ensuring safety during the mining process.

[0042] In a preferred embodiment of the above embodiments, the upper coal seam small mining area 6 and the first lower coal seam small mining area 15 are mined by blasting mining or ordinary mining methods, and the upper coal seam large mining area 7, the first lower coal seam large mining area 16, and the second lower coal seam mining area 19 are mined by fully mechanized mining methods. Since the original coal reserves in the small mining area are small, blasting mining can give full play to its advantages of less investment, strong adaptability, simple operation and management, while the original coal reserves in the large mining area are large, and fully mechanized mining can give full play to its advantages of high yield and high efficiency.

[0043] In a preferred implementation of the above embodiments, the side of the upper cutting roadway 5 close to the small mining area 6 of the upper coal seam is supported by hydraulic supports, and the side of the upper cutting roadway 5 close to the large mining area 7 of the upper coal seam is supported by the self - supporting equipment of the fully - mechanized mining equipment.

[0044] Specifically, the method for retaining roadway along the goaf of the upper coal seam return roadway includes: as the mining face of the large mining area 7 of the upper coal seam advances forward, a wall is constructed behind the fully - mechanized mining equipment in the large mining area 7 of the upper coal seam for support, so as to jointly form a roadway retained along the goaf with the hydraulic support on the side of the upper cutting roadway 5 close to the small mining area 6 of the upper coal seam.

[0045] The above support method and the method for retaining roadway along the goaf are simple to operate, easy to implement, and do not require special equipment, achieving the effects of reducing roadway drivage and increasing coal resource recovery.

[0046] In a preferred implementation of the above embodiments, the side of the first lower cutting roadway close to the small mining area 15 of the first lower coal seam is supported by hydraulic supports, and the side of the first lower cutting roadway close to the large mining area 16 of the first lower coal seam is supported by the self - supporting equipment of the fully - mechanized mining equipment.

[0047] Specifically, the method for retaining roadway along the goaf of the first lower coal seam return roadway includes: as the mining face of the small mining area 15 of the first lower coal seam advances forward, a wall is constructed behind the hydraulic support in the small mining area 15 of the first lower coal seam for support, so as to jointly form a roadway retained along the goaf with the self - supporting equipment of the fully - mechanized mining equipment on the side of the first lower cutting roadway close to the large mining area 16 of the first lower coal seam.

[0048] The above support method and the method for retaining roadway along the goaf are simple to operate, easy to implement, and do not require special equipment, achieving the effects of reducing roadway drivage and increasing coal resource recovery.

[0049] In a preferred implementation of the above embodiments, the wall support is a sandwich wall made of high - water material. A plastic film is attached to the outer wall of the sandwich wall to prevent it from contacting air. A ventilation pipe is arranged in the sandwich wall, and air holes are evenly spaced on the pipe wall of the ventilation pipe. When it is necessary to collapse the roof of the goaf, carbon dioxide is introduced into the ventilation pipe to cause the high - water material to carbonize and decompose, thereby releasing the support for the roof of the goaf and enabling the natural collapse of the roof of the goaf.

[0050] The above - mentioned setting method of the wall support can decompose and collapse the wall by introducing carbon dioxide, thus avoiding stress concentration caused by the remaining wall, enabling the natural collapse of the coal seam roof, and fully releasing the overburden stress around the coal seam.

[0051] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and the examples shown and described herein.

Claims

1. A method for coordinated mining of close coal seams, characterized in that, Including: Arrange a first transportation roadway and a first track roadway along the upper coal seam or its roof and floor. Drive an upper transportation crossheading communicating with the first transportation roadway and an upper track crossheading communicating with the first track roadway in the upper coal seam. Drive an upper cutting roadway between the upper transportation crossheading and the upper track crossheading to connect the upper transportation crossheading and the upper track crossheading. The upper cutting roadway is close to the ends of the upper transportation crossheading and the upper track crossheading, so as to form a small mining area of the upper coal seam on one side of the upper cutting roadway and a large mining area of the upper coal seam on the other side. Set supports in the upper cutting roadway to form a mining roadway for the upper coal seam; Arrange a second transportation roadway and a second track roadway along the lower coal seam or its roof and floor. Drive a coal haulage rise of the lower coal seam communicating with the second transportation roadway and a track rise of the lower coal seam communicating with the second track roadway on one side of the lower coal seam boundary. The roadway of the track rise of the lower coal seam is deeper than that of the coal haulage rise of the lower coal seam. The roadway directions of the coal haulage rise of the lower coal seam and the track rise of the lower coal seam are the same as those of the upper transportation crossheading and the upper track crossheading. Drive a first lower transportation crossheading at the end of the coal haulage rise of the lower coal seam. The head of the first lower transportation crossheading is connected to the roadway of the track rise of the lower coal seam. Drive a first lower track crossheading at the end of the track rise of the lower coal seam. The roadway directions of the first lower transportation crossheading and the first lower track crossheading are the same as that of the upper cutting roadway. The first lower transportation crossheading is arranged staggeredly with the upper cutting roadway. Drive a first lower cutting roadway between the first lower transportation crossheading and the first lower track crossheading. The roadway direction of the first lower cutting roadway is perpendicular to that of the upper cutting roadway and the first lower cutting roadway is arranged staggeredly with the upper transportation crossheading. The first lower cutting roadway is close to the ends of the first lower transportation crossheading and the first lower track crossheading, so as to form a first small mining area of the lower coal seam on one side of the first lower cutting roadway and a first large mining area of the lower coal seam on the other side. Set supports in the first lower cutting roadway to form a mining roadway for the first lower coal seam.

2. The method for coordinated mining of close coal seams according to claim 1, characterized in that, It also includes: Carry out mining on the large mining area of the upper coal seam, and at the same time carry out mining on the first small mining area of the lower coal seam. Leave the gob-side entry retaining for the mining roadway of the upper coal seam and the mining roadway of the first lower coal seam. When the first small mining area of the lower coal seam is mined out, adopt a direct caving management method for the roof of the first small mining area of the lower coal seam; When the gob area of the large mining area of the upper coal seam crosses the first lower transportation crossheading, start to carry out mining on the small mining area of the upper coal seam, and at the same time continue to carry out mining on the large mining area of the upper coal seam until both the large mining area of the upper coal seam and the small mining area of the upper coal seam are mined out, and then adopt a direct caving treatment method for the roof of the upper coal seam; Carry out mining on the first large mining area of the lower coal seam until the first large mining area of the lower coal seam is mined out. Leave the gob-side entry retaining for the first lower transportation crossheading, and then adopt a direct caving treatment method for the roof of the first small mining area of the lower coal seam, the roof of the first large mining area of the lower coal seam, the roof of the mining roadway of the first lower coal seam and the roof of the first lower track crossheading; Drive a second lower transportation crossheading in the middle of the roadway of the coal haulage rise of the lower coal seam. The roadway direction of the second lower transportation crossheading is the same as that of the first lower transportation crossheading. Use the first lower transportation crossheading as the second lower track crossheading. Drive a second lower cutting roadway between the ends of the second lower track crossheading and the second lower transportation crossheading to form a working face of the second lower coal seam mining area adjacent to the first small mining area of the lower coal seam and the first large mining area of the lower coal seam; The second lower coal seam mining area is mined until the second lower coal seam mining area is mined out.

3. The method for coordinated mining of adjacent coal seams according to claim 2, characterized in that The offset distance between the upper cutting eye and the first lower transport chute is 10 meters, and the offset distance between the first lower cutting eye and the upper transport chute is 8 meters.

4. The method for coordinated mining of close coal seams according to claim 2, characterized in that, The upper coal seam small mining area and the first lower coal seam small mining area are mined by blasting or general mining, and the upper coal seam large mining area, the first lower coal seam large mining area and the second lower coal seam mining area are mined by fully mechanized mining.

5. The method for coordinated mining of adjacent coal seams according to claim 4, characterized in that, A hydraulic support is used for support on one side of the upper cutting eye close to the small mining area of ​​the upper coal seam, and a fully mechanized mining equipment is used for support on one side of the upper cutting eye close to the large mining area of ​​the upper coal seam.

6. The method for coordinated mining of adjacent coal seams according to claim 5, characterized in that, The method of retaining a goaf in the upper coal seam mining tunnel includes: as the mining face of the large mining area of ​​the upper coal seam advances forward, a wall support is constructed behind the fully mechanized mining equipment in the large mining area of ​​the upper coal seam, thereby forming a goaf together with the hydraulic support support on one side of the upper cutting eye close to the small mining area of ​​the upper coal seam.

7. The method for coordinated mining of close coal seams according to claim 4, characterized in that, A hydraulic support is used for support on one side of the first lower cutting eye close to a small mining area of ​​the first lower coal seam, and a fully mechanized mining equipment is used for support on one side of the first lower cutting eye close to a large mining area of ​​the first lower coal seam.

8. The method for coordinated mining of close coal seams according to claim 7, characterized in that, The method for retaining a lane along the goaf in the first lower coal seam mining tunnel includes: as the mining face of the small mining area of ​​the first lower coal seam advances forward, a wall support is constructed behind the hydraulic support support of the small mining area of ​​the first lower coal seam, thereby forming a lane along the goaf together with the support provided by the comprehensive mining equipment on one side of the first lower coal seam in the first cutting eye close to the large mining area of ​​the first lower coal seam.

9. The method for coordinated mining of close coal seams according to claim 6 or 8, characterized in that, The wall support is built of high-water-density materials into sandwich walls, and plastic film is attached to the outer wall of the sandwich wall to prevent it from contacting the air. A ventilation pipe is arranged in the sandwich wall, and air holes are evenly spaced on the wall of the ventilation pipe. When the roof of the goaf needs to be collapsed, carbon dioxide is introduced into the ventilation pipe to carbonize and decompose the high-water-density materials, thereby releasing the support for the roof of the goaf and causing the roof of the goaf to collapse naturally.

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