A temporary support method for gob-side entry retaining of a thin coal seam side-cutting in-cutter mining face

Abstract

The application provides a thin coal seam side cutting in knife recovery working face gob-side entry retaining temporary support method, and belongs to the technical field of thin coal seam fully mechanized working face support underground. The method can realize safe, efficient and long distance temporary support of the surrounding rock of the gob-side entry retaining during the gob-side entry retaining and the secondary mining influence period. The temporary support has the advantages of fast support speed, pressure bearing, high strength, recycling and reuse, etc. Under the action of the temporary support, the temporary support device can provide a uniform initial active stress for the roof of the gob-side entry retaining, and the stress can basically cover the roof within the width of the roadway. The temporary support and the roadway bolt and anchor support jointly act to inhibit the development of the roof separation of the roadway, optimize the stress state of the surrounding rock of the roadway, slow down the stress of the overburden acting on the side of the roadway, and jointly control the deformation of the surrounding rock of the roadway with the roadway bolt and anchor support and the temporary support, thereby keeping the integrity and stability of the surrounding rock of the roadway.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of thin coal seam fully mechanized working face support in underground coal mine, and specifically discloses a temporary support method for gob-side entry retaining of thin coal seam side-cutting and entry-retaining mining working face. BACKGROUND

[0002] With the gradual decrease of medium-thick coal seams, more and more mines begin to pay attention to the safe and efficient mining of thin coal seams. At present, longwall mining method is generally used for thin coal seam mining. Before mining, the mining roadway and cut hole need to be excavated in advance to form a ventilation and transportation system. Influenced by the occurrence conditions of coal seams, the mining roadway of thin coal seam fully mechanized working face is a half-coal and rock roadway. More than half of the rock stratum needs to be cut during the actual excavation process. The excavation difficulty and cost of the mining roadway during the excavation process are higher than those of the full-coal roadway excavation. Unlike the mining roadway of medium-thick coal seam, the mining roadway of thin coal seam fully mechanized working face is generally short and low. In order to realize efficient side-cutting and entry-retaining of the working face and ensure the actual operation space of the mining roadway, the design width of the mining roadway is large, which is generally a wide and short half-coal and rock roadway. In order to save the excavation cost and improve the recovery rate of coal resources, more and more thin coal seam fully mechanized working faces use the gob-side entry retaining technology. Influenced by the gob-side entry retaining process and the cross section of the roadway, the roadway is greatly affected by the mining of the working face during the gob-side entry retaining process. The surrounding rock of the roadway moves violently in the early stage of the roadway formation. The stress on the surrounding rock is complex, and the stability of the surrounding rock is poor. After the gob-side entry retaining, the roadway needs to serve the next working face. Influenced by the secondary mining, the deformation of the surrounding rock is further increased. In order to ensure the safe implementation and subsequent effective use of the gob-side entry retaining, the surrounding rock is often temporarily supported for a long distance during the entry retaining process. The temporary support of the surrounding rock of the entry retaining mainly includes single hydraulic support and unitary temporary support device. In the actual support process, the single hydraulic support has the problems of many required workers, high labor intensity, low support efficiency, certain safety hazards, etc. In addition, the temporary support is carried out by different workers, the actual support intensity is uneven, the adaptability of the single support to the surrounding rock is poor, and the actual support effect is not ideal. The unitary temporary support device is generally arranged in parallel in the entry retaining. Generally, two support devices are arranged in parallel in one row. Influenced by the transportation space requirement, the two temporary support devices are close to the sidewall of the roadway. Since the width of the mining roadway required by the thin coal seam side-cutting and entry-retaining working face is large, the distance of the suspended roof in the middle of the roadway is long when the unitary temporary support device is used for temporary support. Under the influence of the violent mining, the deformation of the roof and floor in the middle of the roadway in the temporary support area of the surrounding rock in the early stage of the roadway formation is large, and the actual support effect is poor. The safety, technology and economic benefits of the temporary support of the thin coal seam side-cutting and entry-retaining working face need to be further improved. SUMMARY

[0003] The purpose of the present application is to provide a temporary support method for gob-side entry retaining of thin coal seam side-cutting and entry-retaining mining working face, which realizes the rapid, timely and overall support of the roadway during the gob-side entry retaining.

[0004] The temporary support method for the gob-side entry retaining of the thin coal seam side-cutting and in-drawing working face, comprising the following steps:

[0005] S1, before the thin coal seam is mined, two mining roadways of a transportation crossheading and an air return crossheading are parallelly excavated at both sides of a working face planning area, a first end of the transportation crossheading and the air return crossheading is connected through a working face cut, a second end is connected through a withdrawal channel, a working face channel is formed, mining equipment is arranged, and a first working face is formed;

[0006] S2, the transportation crossheading is used as the gob-side entry retaining, temporary support devices are continuously and intermittently added behind the head of the scraper conveyor as the first working face advances, until the first working face advances to a preset distance from the working face cut, the addition of the temporary support devices is stopped, and a temporary support interval within the preset distance behind the first working face is formed;

[0007] S3, as the first working face advances forward, the temporary support devices are continuously and intermittently added behind the head of the scraper conveyor, and the temporary support devices beyond the preset distance are withdrawn one by one, so that the temporary support interval behind the head of the scraper conveyor is kept within the preset distance, and dynamic temporary support is formed;

[0008] S4, when the first working face reaches a stop line, the mining is stopped, the mining is completed, the temporary support devices in the temporary support interval behind the stop line are stopped from being recovered, the mining equipment is withdrawn, and a preset time is waited until the surrounding rock of the gob-side entry retaining is affected by mining and tends to be stable, then the temporary support devices in the temporary support interval are recovered one by one from back to front, and the temporary support of the gob-side entry retaining during the mining of the first working face is completed;

[0009] S5, the transportation crossheading of the first working face becomes the air return crossheading of a second working face, and is used as the gob-side entry retaining, a transportation crossheading parallel to the air return crossheading is excavated, a first end of the transportation crossheading and the air return crossheading is connected through a working face cut, a second end is connected through a withdrawal channel, a working face channel is formed, mining equipment is arranged, a second working face is formed, and before the second working face is mined, temporary support devices are arranged in the preset distance in front of the tail of the scraper conveyor from back to front, and a temporary support interval is formed;

[0010] S6, as the second working face is mined, temporary support devices are continuously and intermittently added in front of the temporary support device at the front in step S5, and the temporary support devices in front of the tail of the scraper conveyor are recovered one by one, so that the temporary support interval in front of the tail of the scraper conveyor is kept within the preset distance, and dynamic temporary support is formed;

[0011] S7, stopping the mining when the second working face enters the stop mining line, stopping the mining, stopping the recovery of the temporary support device in the interval of the temporary support in front of the stop mining line, waiting for the recovery of the mining equipment of the second working face, and then recovering the temporary support device from front to back to complete the temporary support of the gob-side entry driving during the mining of the first and second working faces;

[0012] S8, supporting the next working face according to steps S5-S7 to complete the mining of the coal seam.

[0013] Further, the transportation crossheading and the air return crossheading adopt the driving mode of breaking the roof and the floor.

[0014] Further, the mining equipment comprises an end hydraulic support, a working face hydraulic support, a low-type scraper conveyor, a side-cutting and in-cutting coal mining device, and a transfer and crushing device; the end hydraulic support, the working face hydraulic support, the low-type scraper conveyor, and the side-cutting and in-cutting coal mining device are arranged in the working face open-off cut, wherein the low-type scraper conveyor is arranged along the length direction of the working face, the head of the scraper conveyor and the tail of the scraper conveyor are located in the transportation crossheading and the air return crossheading respectively, and the side-cutting and in-cutting coal mining device is straddled on the low-type scraper conveyor; the transfer and crushing device is arranged in the transportation crossheading.

[0015] Further, the pitch of the temporary support device is a multiple of the pitch of the roadway anchor rod and anchor cable support, the temporary support device directly acts on the roof of the roadway, and does not contact the anchor rod and anchor cable support, thereby avoiding the damage of the temporary support device to the anchor rod and anchor cable.

[0016] Further, the temporary support device comprises a crossbeam, an elastic buffer mechanism, a hydraulic oil cylinder, and a bottom connecting mechanism connected in sequence from top to bottom.

[0017] Further, the crossbeam is a rectangular beam comprising a main beam and telescopic beams slidingly arranged at both ends of the main beam, the length of the crossbeam can be adjusted according to the width of the roadway to meet the requirements of the support of the roof within the range of the width of the roadway; each temporary support device is provided with four elastic buffer mechanisms and four hydraulic oil cylinders; the four elastic buffer mechanisms are located at the four corners of the main beam, and the two ends are connected to the bottom surface of the main beam and the top end of the hydraulic oil cylinder respectively; the elastic buffer mechanism can be deformed according to the actual pressure of the roof of the roadway, and the maximum deformation amount is 500 mm, which effectively avoids the damage of the temporary support device to the roof of the roadway during the temporary support process, and maintains the integrity and stability of the roof of the roadway.

[0018] Further, the hydraulic oil cylinder is a double telescopic oil cylinder.

[0019] Further, the bottom connecting mechanism is a rectangular plate structure, the top surface is provided with a connecting head for connecting with the bottom end of the hydraulic oil cylinder, and the bottom surface is provided with grooves at intervals, which effectively increases the friction between the bottom connecting mechanism and the floor of the roadway, and at the same time avoids the damage to the floor of the roadway.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] The temporary support method for the gob-side entry retaining of the thin coal seam side-cutting and in-drawing mining working face can realize safe, efficient and long-distance temporary support of the gob-side entry retaining during the gob-side entry retaining and the secondary mining influence period, and the temporary support has the advantages of fast support speed, pressure bearing, high strength, recycling and reuse, etc. Under the action of the temporary support, the temporary support device can provide a uniform initial active stress for the roof of the gob-side entry retaining, and the stress can basically cover the roof within the width of the roadway. The temporary support and the roadway bolt and anchor support jointly act to inhibit the development of the roof separation of the roadway, optimize the stress state of the roadway surrounding rock, slow down the stress of the overburden strata acting on the side of the roadway, and the roadway bolt and anchor support and the temporary support jointly control the deformation of the roadway surrounding rock to maintain the integrity and stability of the roadway surrounding rock. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the specific embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0023] Figure 1 Layout for the gob-side entry retaining of the thin coal seam side-cutting and in-drawing mining working face;

[0024] Figure 2 Layout for the temporary support of the gob-side entry retaining during the mining of the 3201 working face;

[0025] Figure 3 Layout for the temporary support of the gob-side entry retaining during the mining of the 3203 working face;

[0026] Figure 4 Front view of the temporary support device (horizontal beam extension state);

[0027] Figure 5 Front view of the temporary support device (horizontal beam contraction state);

[0028] Figure 6 Side view of the temporary support device;

[0029] Figure 7 Schematic view of the bottom abutting mechanism in the temporary support device.

[0030] In the figure: 1 - end hydraulic support; 2 - working face hydraulic support; 3 - low scraper conveyor; 3.1 - scraper conveyor head; 3.2 - scraper conveyor tail; 4 - side cutting knife coal mining device; 5 - transfer crushing device; 6 - working face cut; 7 - transport crossheading; 8 - return air crossheading; 9 - temporary support device; 9.1 - main beam; 9.2 - telescopic beam; 9.3 - elastic buffer mechanism; 9.4 - hydraulic cylinder; 9.5 - bottom connecting mechanism; 9.6 - groove. DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be described clearly and completely below in combination with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0032] In the embodiment, the present main mining coal seam 2# of Shanxi group in a mine, the coal seam thickness is 0.80-1.53m, the average thickness is 1.21m, the coal seam structure is simple, and is developed stably without interlayer. The basic roof of the coal seam is medium-fine sandstone, the average thickness is 4.16m; the direct roof is mudstone and sandy mudstone, the average thickness is 3.86m; the coal seam floor is mudstone and sandy mudstone, the average thickness is 1.95m; the basic floor of the coal seam is siltstone, the average thickness is 5.46m. The first mining working face of the three panel area of the mine is 3201 working face, the transport crossheading and the return air crossheading are designed as rectangular section, the roadway width is 6.0m, the height is 2.5m, and the top is broken and the bottom is excavated; the transport crossheading of 3201 working face is gob-side entry retaining, and the gob-side entry retaining is used as the return air crossheading of the adjacent next working face 3203 working face. The length of 3201 working face and 3203 working face is 180m, and the advancing length is about 3200m.

[0033] In the embodiment, the temporary support method of the thin coal seam side cutting knife recovery working face gob-side entry retaining specifically includes the following steps.

[0034] S1, before the thin coal seam recovery, two recovery roadways of the transport crossheading 7 and the return air crossheading 8 are excavated in parallel on both sides of the working face planning area, the first end of the transport crossheading 7 and the return air crossheading 8 is connected through the working face cut 6, and the second end is connected with each other through the withdrawal channel to form a recovery working face channel, the recovery equipment is arranged to form the 3201 working face, the floor of the 3201 return air crossheading and the 3201 transport crossheading is treated by concrete hardening during the excavation process, and after the completion of the roadway excavation, the 3201 working face is prepared for recovery.

[0035] S2, the 3201 transportation crossheading is used as a gob-side entry, and with the advance of the 3201 working face, temporary support devices 9 are continuously and intermittently added behind the scraper conveyor head 3.1 until the 3201 working face advances to a length of 200 m from the working face open-off cut 6, at which point the addition of temporary support devices 9 is stopped, forming a long-distance temporary support section within 200 m behind the 3201 working face.

[0036] The spacing of the temporary support devices 9 is twice the spacing (800 mm) of the roadway bolt and anchor support of the 3201 transportation crossheading, i.e. 1600 mm, and the temporary support devices 9 are arranged between adjacent two rows of anchor bolts, while being in a position without an anchor, so as to ensure that the temporary support devices 9 do not interfere with the roadway bolt and anchor support during initial support.

[0037] S3, with the forward mining of the 3201 working face, the temporary support devices 9 are continuously and intermittently added behind the scraper conveyor head 3.1, while the temporary support devices 9 beyond 200 m are withdrawn in stages, so that the temporary support section behind the scraper conveyor head 3.1 is kept within 200 m, thereby ensuring long-distance dynamic temporary support within the initial 200 m range of the gob-side entry during the advance of the working face.

[0038] S4, when the 3201 working face reaches the stop line, the mining is stopped, the temporary support devices 9 within 200 m behind the stop line are stopped from being recovered, the mining equipment is withdrawn, and the temporary support state is continuously maintained until the 3201 transportation crossheading surrounding rock migration tends to be stable after 3-4 months, at which point the temporary support devices 9 in the temporary support section are recovered from back to front, the temporary support devices 9 are strictly prohibited from damaging the roadway bolt and anchor support during the recovery process, and the temporary support of the gob-side entry during the mining of the 3201 working face is completed.

[0039] S5, according to the mining connection situation, the 3203 working face is started to be mined, the 3201 transportation crossheading is used as the 3203 working face return air crossheading for continuous use, and before the 3203 return air crossheading is arranged and mining is started, the temporary support devices 9 are arranged in the 3203 return air crossheading from 100 m in front of the scraper conveyor tail 3.2 back to front in stages, thereby forming a temporary support section with a length of 100 m.

[0040] The spacing of the temporary support devices 9 is twice the spacing (800 mm) of the roadway bolt and anchor support of the 3203 return air crossheading, i.e. 1600 mm, and the temporary support devices 9 are arranged between adjacent two rows of anchor bolts, while being in a position without an anchor, so as to ensure that the temporary support devices 9 do not interfere with the roadway bolt and anchor support during initial support.

[0041] S6, with the mining of the 3203 working face, the temporary support device 9 in front of the frontmost temporary support device 9 in step S5 is continuously increased at intervals, and the temporary support device 9 in front of the tail of the scraper conveyor 3.2 is recovered in batches, so that the temporary support interval in front of the tail of the scraper conveyor 3.2 is kept within 100 m, forming a dynamic temporary support.

[0042] S7, the 3203 working face stops mining when it reaches the stop line, the mining is completed, the temporary support device 9 within 100 m in front of the stop line is stopped, and the temporary support device 9 is recovered in sequence from front to back after the mining equipment of the 3203 working face is withdrawn, and the temporary support along the empty roadway during the mining of the 3201 and 3203 working faces is completed after the recovery of all the temporary support devices 9 is completed.

[0043] S8, according to steps S5-S7, the next working face is supported to leave the roadway until the mining of the coal seam in the layer is completed.

[0044] The mining equipment includes an end hydraulic support 1, a working face hydraulic support 2, a low-type scraper conveyor 3, a side-cutting cutter mining device 4, and a transfer crushing device 5; the end hydraulic support 1, the working face hydraulic support 2, the low-type scraper conveyor 3, and the side-cutting cutter mining device 4 are arranged in the working face cut 6, wherein the low-type scraper conveyor 3 is arranged along the length direction of the working face, the head 3.1 and the tail 3.2 of the scraper conveyor are respectively located in the transportation crossheading 7 and the return air crossheading 8, and the side-cutting cutter mining device 4 is astride on the low-type scraper conveyor 3; the transfer crushing device 4 is arranged in the transportation crossheading 6.

[0045] The temporary support device 9 includes a crossbeam, an elastic buffer mechanism 9.3, a hydraulic oil cylinder 9.4, and a bottom connecting mechanism 9.5 connected in sequence from top to bottom. The crossbeam is a rectangular beam, including a main beam 9.1 and telescopic beams 9.2 slidingly arranged at both ends of the main beam 9.1; each temporary support device is provided with four sets of elastic buffer mechanisms 9.3 and four hydraulic oil cylinders 9.4; the four sets of elastic buffer mechanisms 9.3 are located at the four corners of the main beam 9.1, and the two ends are respectively connected to the bottom surface of the main beam 9.1 and the top end of the hydraulic oil cylinder 9.4. The hydraulic oil cylinder 9.4 is a double telescopic oil cylinder. The bottom connecting mechanism 9.5 is a rectangular plate structure, and the top surface is provided with a connecting head for connecting with the bottom end of the hydraulic oil cylinder 9.4, and the bottom surface is provided with grooves 9.6 at intervals.

[0046] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A temporary support method for gob-side entry retaining of a thin-seam side-cutting in-cutter mining face, characterized in that, Comprising the following steps: S1, before mining the thin coal seam, two mining roadways of the transportation crossheading and the return air crossheading are excavated in parallel on both sides of the working face planning area, the first ends of the transportation crossheading and the return air crossheading are connected through the working face cut, the second ends are connected through the withdrawal channel, a mining working face channel is formed, the mining equipment is arranged, and a first working face is formed; S2, the transportation crossheading is used as the gob-side entry retaining, with the advancement of the first working face, temporary support devices are continuously and intermittently added behind the head of the scraper conveyor, until the first working face reaches a preset distance from the working face cut, the addition of the temporary support devices is stopped, and a temporary support interval within the preset distance behind the first working face is formed; S3, with the forward mining of the first working face, the temporary support devices are continuously and intermittently added behind the head of the scraper conveyor, and the temporary support devices exceeding the preset distance are withdrawn one by one, so that the temporary support interval behind the head of the scraper conveyor is kept within the preset distance, and dynamic temporary support is formed; S4, when the first working face reaches the stop line, the mining is stopped, the mining is completed, the temporary support devices in the temporary support interval behind the stop line are stopped, the mining equipment is withdrawn, and a preset time is waited until the surrounding rock of the gob-side entry retaining is affected by the mining and tends to be stable, then the temporary support devices in the temporary support interval are recovered from back to front, and the temporary support of the gob-side entry retaining during the mining of the first working face is completed; S5, the transportation crossheading of the first working face becomes the return air crossheading of the second working face, and is used as the gob-side entry retaining, a transportation crossheading parallel to the return air crossheading is excavated, the first ends of the transportation crossheading and the return air crossheading are connected through the working face cut, the second ends are connected through the withdrawal channel, a mining working face channel is formed, the mining equipment is arranged, and a second working face is formed, before mining the second working face, temporary support devices are arranged in the preset distance in front of the tail of the scraper conveyor from back to front, and a temporary support interval is formed; S6, with the mining of the second working face, temporary support devices are continuously and intermittently added in front of the frontmost temporary support device in step S5, and the temporary support devices in front of the tail of the scraper conveyor are recovered one by one, so that the temporary support interval in front of the tail of the scraper conveyor is kept within the preset distance, and dynamic temporary support is formed; S7, when the second working face reaches the stop line, the mining is stopped, the mining is completed, the recovery of the temporary support devices in the temporary support interval in front of the stop line is stopped, after the mining equipment of the second working face is withdrawn, the temporary support devices are recovered from front to back, and the temporary support of the gob-side entry retaining during the mining of the first and second working faces is completed; S8, according to steps S5-S7, the entry retaining of the next working face is supported, until the mining of the current coal seam is completed.

2. The temporary support method of gobs along the sidewall cutting-in of thin coal seam mining face of the claim 1, characterized in that, The transportation crossheading and the return air crossheading adopt the top-breaking and bottom-excavating excavation mode.

3. The temporary support method of gob-side entry retaining of thin-seam side-cutting in-draught mining face according to claim 1, characterized in that, The mining equipment includes a head hydraulic support, a working face hydraulic support, a low-type scraper conveyor, a side-cutting and infeed cutter mining device, and a transfer and crushing device. The end hydraulic support, the working face hydraulic support, the low-type scraper conveyor and the side-cutting infeed coal mining device are arranged in the working face cut hole, wherein the low-type scraper conveyor is arranged along the length direction of the working face, the scraper conveyor head and the scraper conveyor tail are respectively located in the transportation crossheading and the air return crossheading, and the side-cutting infeed coal mining device is straddled on the low-type scraper conveyor; and the transfer and crushing device is arranged in the transportation crossheading.

4. The temporary support method of gob-side entry retaining of thin-seam side-cutting in-cutter mining face according to claim 1, characterized in that, The row distance of the temporary support device is a multiple of the row distance of the roadway anchor rod and anchor cable support, and the temporary support device does not contact the roadway anchor rod and anchor cable support.

5. The temporary support method of gobs along the wall in the thin coal seam side cutting in knife mining face according to claim 1 or 4, characterized in that, The temporary support device comprises, from top to bottom, a crossbeam, an elastic buffering mechanism, a hydraulic oil cylinder and a bottom connecting mechanism.

6. The temporary support method of gob-side entry retaining of thin-seam side-cutting in-cutter mining face according to claim 5, characterized in that, The crossbeam is a rectangular beam, comprising a main beam and telescopic beams slidingly arranged at both ends of the main beam. Each temporary support device is provided with four sets of elastic buffering mechanisms and four hydraulic oil cylinders. The four sets of elastic buffering mechanisms are located at four corners of the main beam, and the two ends are respectively connected to the bottom surface of the main beam and the top end of the hydraulic oil cylinder.

7. The temporary support method of gobs along the wall in the thin coal seam side cutting-in knife mining face according to claim 6, characterized in that, The hydraulic oil cylinder is a double telescopic oil cylinder.

8. The temporary support method of gobs along the wall in the thin coal seam side cutting-in knife mining face according to claim 7, characterized in that, The bottom connecting mechanism is a rectangular plate structure, the top surface of which is provided with a connecting head for connecting with the bottom end of the hydraulic oil cylinder, and the bottom surface is provided with grooves at intervals.

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