Roof Fall Protection Devices and Methods for High-Ground Fully Mechanized Mining Faces

Abstract

This invention provides a roof fall and rib collapse protection device and method for fully mechanized longwall mining faces with high mining height. The protection device includes a connecting seat, a hydraulic jack, a forward probe beam, and a cutting section. The connecting seat is fixedly installed on the top beam of the hydraulic support. The rear end of the hydraulic jack is fixedly connected to the connecting seat. The forward probe beam is fixedly connected to the front end of the hydraulic jack. The cutting section is located at the front end of the forward probe beam. The protection method includes determining the size parameters of the pressure relief groove; cutting the coal wall of the working face ahead of the cutting section to form the pressure relief groove; extending the forward probe beam into the pressure relief groove to provide full-time support for the roof; cutting coal 3-5m behind the pressure relief groove; and moving the support frame and scraper conveyor about 5m behind the coal mining machine. The protection device is moved forward as a whole, and the pressure relief groove is deepened by the cutting section. The forward probe beam is extended to support the roof. The above steps are repeated to complete coal cutting, support moving, and scraper conveyor pushing. This solves the problem of intermittent passive protection against coal wall rib collapse and roof fall in fully mechanized longwall mining faces with high mining height in the prior art.

Description

Technical Field

[0001] This invention relates to the field of coal mining, and more specifically, to a roof fall and rib collapse protection device and method for fully mechanized longwall mining faces with high mining height. Background Technology

[0002] In my country's existing coal reserves and production, thick coal seams (thickness > 3.5m) account for approximately 45% of both, making them the main coal seams for achieving high-yield and efficient mining in my country and of great significance to national energy security. Currently, the main methods for mining thick coal seams include layered mining, fully mechanized top-coal caving mining, and high-extraction fully mechanized mining. Among these, high-extraction fully mechanized mining technology, after long-term development, has solved many problems such as low coal resource recovery efficiency and safety in layered mining of thick coal seams, and the large workload and complex process of fully mechanized top-coal caving mining. It has outstanding advantages such as simple process, high extraction rate, and large production capacity, and has been widely used and rapidly developed. Currently, the key technologies for 10m ultra-high extraction hydraulic supports and supporting equipment have been successfully applied in the Caojiatan Coal Mine of Shaanxi Coal and Chemical Industry Group, providing strong support for the release of high-quality production capacity and the high-quality development of the coal industry.

[0003] The coal face failure and instability process in high-extraction fully mechanized mining faces mainly consists of two stages: structural instability and functional instability. As the mining height increases, the exposed area of ​​the coal face expands. When the coal face support pressure exceeds the ultimate support strength of the coal body, the coal face undergoes plastic deformation but still maintains its structural integrity. At this point, structural instability occurs, leading to coal face spalling. Under the continuous deformation and pressure of the roof, and due to the presence of the unsupported roof distance, the already structurally unstable coal face further induces roof collapse, resulting in roof fall in front of the working face. At this point, functional instability occurs. In summary, the principle for preventing coal face spalling and roof fall in working faces is to mitigate structural instability and control functional instability.

[0004] Current measures for controlling roof collapse and side fall in high-mining coal seams primarily focus on increasing the support force at the front end of the roof beam and optimizing the support end structure. The support principle of traditional hydraulic supports is as follows: Figure 1 As shown, the current hydraulic supports for high mining heights mainly adopt a three-stage side protection device. However, this device lacks the technical capability to provide intermittent passive protection against coal wall spalling and roof collapse in front of the support in fully mechanized mining faces with high mining heights. This makes the coal wall in the working face extremely prone to spalling under the pressure of the advance support, and can induce disasters such as roof collapse in front of the support. Summary of the Invention

[0005] The main objective of this invention is to provide a roof and side collapse protection device and method for high-extraction fully mechanized mining faces, so as to solve the problem of insufficient intermittent passive protection technology for coal wall collapse and roof leakage in existing high-extraction fully mechanized mining faces, and realize all-time active protection for high-extraction fully mechanized mining faces.

[0006] To achieve the above objectives, the present invention provides a roof fall and rib fall protection device and method for fully mechanized mining faces with high mining height.

[0007] To achieve the above objectives, according to one aspect of the present invention, a roof fall and rib fall protection device for a high-extraction fully mechanized mining face is provided, comprising: a connecting seat, fixedly installed on the top beam of a hydraulic support; a hydraulic jack, the rear end of which is fixedly connected to the connecting seat; a front probe beam, the front probe beam being fixedly connected to the front end of the hydraulic jack; and a cutting section disposed at the front end of the front probe beam; wherein the hydraulic jack is used to drive the cutting section to move toward or away from the coal wall of the high-extraction fully mechanized mining face via the front probe beam, and the cutting section is used to pre-cut the coal wall at a preset position in the high-extraction fully mechanized mining face to form a pressure relief groove.

[0008] Furthermore, the front end of the top beam is a box structure, and the front extension beam can be telescopically inserted into the box structure of the top beam along the length of the top beam to share the pressure of the top plate borne by the top beam.

[0009] Furthermore, the rear end of the front beam is a box structure, and the front end of the hydraulic jack extends into the box structure at the rear end of the front beam and is fixedly connected to the front beam.

[0010] Furthermore, there are two hydraulic jacks, which are arranged side by side in the transverse direction and fixedly connected to the connecting seat and the front probe beam respectively; the two hydraulic jacks work synchronously to drive the cutting part to move toward or away from the coal wall of the high-extraction fully mechanized mining face.

[0011] Furthermore, the cutting unit includes: a rocker arm, the rear end of which is fixedly mounted on the front end of the front probe beam; a rotating drum, which is rotatably mounted on the front end of the rocker arm; multiple cutting heads, which are arranged in a single spiral on the rotating drum; and a drive mechanism connected to the rotating drum, which drives the rotating drum to rotate so as to cut the coal wall at a preset position in the high-mining-height fully mechanized mining face through the multiple cutting heads.

[0012] Furthermore, the drive mechanism includes: a motor, a reducer, and a coupling, wherein the motor drives the rotating drum to rotate through the reducer and the coupling.

[0013] According to another aspect of the present invention, a method for protecting against roof fall and rib spalling in a high-extraction fully mechanized mining face is provided. This method utilizes the aforementioned roof fall and rib spalling protection device for high-extraction fully mechanized mining faces. The method includes: determining dimensional parameters such as the effective cutting depth D and effective height H of the pressure relief groove formed by cutting the coal wall of the high-extraction fully mechanized mining face; according to the determined dimensions of the pressure relief groove, the coal wall of the high-extraction fully mechanized mining face is pre-cut using the protection device to form the pressure relief groove; the forward probe beam of the protection device is extended into the pressure relief groove to support the roof, and coal is cut using a coal mining machine 3-5m behind the pressure relief groove; the working face is moved and the scraper conveyor is pushed 5m behind the coal mining machine to complete one cycle of mining; the protection device is moved forward as a whole by moving the working face and the pressure relief groove is cut again using the protection device to deepen the pressure relief groove; the forward probe beam of the protection device is extended into the pressure relief groove to support the roof, and the coal mining machine advances one step distance before repeating the above steps to complete coal cutting, moving the frame, and pushing the scraper conveyor.

[0014] Furthermore, the effective cutting depth D and effective height H of the pressure relief groove are related to the height of the longwall mining face, the cutting depth of the coal mining machine, and the rated working resistance of the hydraulic support used, and can be determined by the following formula:

[0015]

[0016]

[0017] In the formula, M is the mining height in meters (m); P is the rated working resistance of the hydraulic support in kN; and d is the cutting depth of the coal mining machine in meters (m).

[0018] The main feature of this invention is the use of a hydraulic support with a roof fall and rib spalling protection device for supporting the surrounding rock of a fully mechanized longwall mining face with high extraction height in thick coal seams. This effectively prevents roof fall and rib spalling in such faces, ensuring the safety and efficiency of mining this type of coal seam. Due to the adoption of the above technical solution, the beneficial effects achieved by this invention compared to existing technologies are:

[0019] I. This invention designs a roof fall and rib collapse protection device for a fully mechanized longwall mining face with high mining height. The roof fall and rib collapse protection device includes a hydraulic support, a connecting seat, a hydraulic jack, a protective beam, and a cutting part. The connecting seat is fixedly installed on the top beam of the hydraulic support. The rear end of the hydraulic jack is fixedly connected to the connecting seat. The protective beam is fixedly connected to the front end of the hydraulic jack. The cutting part is set at the front end of the protective beam. The hydraulic jack is used to drive the cutting part to move towards or away from the fully mechanized longwall mining face through the protective beam. The cutting part is used to cut the coal wall at a preset position on the fully mechanized longwall mining face to form a pressure relief groove.

[0020] Second, this invention employs a roof fall and rib spalling protection device, thereby optimizing and changing the roof fall and rib spalling protection method in high-extraction fully mechanized mining faces. Generally, high-extraction fully mechanized mining faces mainly rely on hydraulic support sidewall plates and forward-extending beams for coal wall spalling and roof fall protection. Due to the influence of the mining process, this is an intermittent, passive protection method. However, this invention releases the coal wall support pressure through an advanced pressure relief groove, and the forward-extending beam extends into the pressure relief groove to form full-time roof support. Therefore, this invention realizes the transformation of existing intermittent passive protection for roof fall and rib spalling in high-extraction fully mechanized mining faces into all-time active protection.

[0021] In summary, this invention improves the universality of fully mechanized mining technology for thick coal seams with high mining height, effectively protects against roof falls and side collapses in high mining faces, and enhances the safety and efficiency of the working face. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 This is a diagram illustrating the support effect of a traditional high-extraction hydraulic support.

[0024] Figure 2 This is a schematic diagram of the structure of a roof fall and side fall protection device for a fully mechanized mining face with a high mining height, which is optional according to an embodiment of the present invention;

[0025] Figure 3 This is a front view structural diagram of a roof fall and rib collapse protection device for a fully mechanized mining face with a high mining height, which is optional according to an embodiment of the present invention;

[0026] Figure 4 This is a top view of a roof fall and side fall protection device for a fully mechanized mining face with a high mining height, which is an optional embodiment of the present invention.

[0027] Figure 5 This is a flowchart of a method for protecting against roof collapse and sidewall slab fall in a fully mechanized mining face, which is optional according to an embodiment of the present invention;

[0028] Figure 6 This is a working plane diagram of a roof fall and sidewall protection method for a high-extraction fully mechanized mining face, which is optional according to an embodiment of the present invention.

[0029] Figure 7 This is a diagram illustrating the support effect of a roof fall and rib collapse protection device and method for a fully mechanized longwall mining face, which is optional according to an embodiment of the present invention.

[0030] The above figures include the following reference numerals:

[0031] 1. Connecting seat; 2. Hydraulic jack; 3. Front probe beam; 4. Cutting section; 41. Rocker arm; 42. Rotary drum; 43. Cutting head; 44. Drive mechanism; 5. Top beam; 61. Coal seam; 62. Traditional high-extraction hydraulic support; 63. Collapsed rock strata; 64. Schematic diagram of pressure distribution in front of coal face support; 65. Coal face of working face; 66. Pressure relief groove. Detailed Implementation

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] The first embodiment of the present invention provides a roof fall and rib collapse protection device for a high-extraction fully mechanized mining face, such as... Figure 2 As shown, the system includes a connecting seat 1, a hydraulic jack 2, a forward probe beam 3, and a cutting section 4. The connecting seat 1 is fixedly installed on the top beam 5 of the hydraulic support. The rear end of the hydraulic jack 2 is fixedly connected to the connecting seat 1. The forward probe beam 3 is fixedly connected to the front end of the hydraulic jack 2. The cutting section 4 is located at the front end of the forward probe beam 3. The hydraulic jack 2 is used to drive the cutting section 4 to move towards or away from the high-extraction fully mechanized mining face via the forward probe beam 3. The cutting section 4 is used to perform advanced cutting of the coal wall at a preset position on the high-extraction fully mechanized mining face to form a pressure relief groove. By cutting the pressure relief groove in advance to release the supporting pressure of the coal wall in the high-extraction fully mechanized mining face, and by supporting the roof of the working face through the forward-extending protective beam, the intermittent passive protection problem of coal wall spalling and roof leakage in the existing technology of high-extraction fully mechanized mining faces is solved.

[0034] Preferably, the device and method are suitable for fully mechanized one-time full-height working faces in coal seams with a thickness of 5 to 10 meters. Under normal circumstances, the working face length is about 320 meters, and the working face length can be appropriately increased in sections with good geological conditions or superior coal seams.

[0035] In specific implementation, such as Figure 2 , Figure 3 and Figure 4 As shown, the front end of the top beam 5 and the rear end of the forward extension beam 3 are both box structures. The forward extension beam 3 is telescopically inserted into the box structure of the top beam 5 along its length. The forward extension beam 3, subjected to the load of the overburden and the support of the coal wall, shares the pressure on the top beam 5, forming complete support for the roof at the working face end. The front end of the hydraulic jack 2 extends into the box structure at the rear end of the forward extension beam 3 and is fixedly connected to it. The box structure allows for the mutual insertion of the hydraulic jack 2, the forward extension beam 3, and the top beam 5, facilitating the forward extension and retraction of the forward extension beam 3. Furthermore, the box structure not only saves materials, thus reducing project costs and energy consumption, but also reduces the structural weight, thereby decreasing the structural load.

[0036] Furthermore, such as Figure 4 As shown, there are two hydraulic jacks 2, which are arranged side by side in the transverse direction and fixedly connected to the connecting seat 1 and the front probe beam 3 respectively. The two hydraulic jacks 2 work synchronously to drive the cutting part 4 to move toward or away from the fully mechanized mining face. The synchronous drive of the two hydraulic jacks 2 can make the movement of the front probe beam 3 and the cutting part 4 more stable.

[0037] Furthermore, the cutting section 4 includes a rocker arm 41, a rotating drum 42, a cutting head 43, and a drive mechanism 44; the rear end of the rocker arm 41 is fixedly installed at the front end of the front probe beam 3; the rotating drum 42 is rotatably installed at the front end of the rocker arm 41, and the front end of the rocker arm 41 can swing through the shaft where the rear end of the rocker arm 41 is located, thereby driving the rotating drum 42 to swing; there are multiple cutting heads 43, which are arranged in a single spiral on the rotating drum 42. Each cutting head 43 consists of a cutting tooth seat and cutting teeth, and can directly act on the crushed coal and rock; the drive mechanism 44 is connected to the rotating drum 42, and the drive mechanism 44 is used to drive the rotating drum 42 to rotate so as to cut the upper coal wall of the high-mining-height fully mechanized mining face through multiple cutting heads 43 to form a pressure relief groove.

[0038] Specifically, the drive mechanism 44 includes: a motor, a reducer, and a coupling. The motor is used to drive the rotating drum 42 to rotate in a preset direction; the reducer is used to change the rotation speed of the rotating drum 42; and the coupling is used to connect the motor and the reducer, as well as the reducer and the rotating drum 42.

[0039] The roof fall and side fall protection device for high-extraction fully mechanized mining faces provided in this embodiment of the invention is compatible with hydraulic support power systems, is simple and convenient to operate, and can be remotely controlled; at the same time, the protection device is small in size, and the cutting part 4 and the front probe beam 3 can be retracted into the box without occupying extra space.

[0040] According to a second embodiment of the present invention, a method for protecting against roof fall and rib spalling in a high-extraction fully mechanized mining face is provided, which utilizes the aforementioned roof fall and rib spalling protection device for high-extraction fully mechanized mining faces, such as... Figure 5 As shown, the protection method includes the following steps:

[0041] Step S102: Determine the dimensions of the pressure relief groove formed by cutting the coal wall of the high-extraction fully mechanized mining face;

[0042] Step S104: Based on the determined dimensions of the pressure relief groove, the coal wall of the high-extraction fully mechanized mining face is pre-cut using a protective device to form the pressure relief groove.

[0043] Step S106: Extend the front probe beam of the protective device into the pressure relief groove to support the roof, and cut the coal using the coal mining machine;

[0044] Step S108: Move the protective device forward as a whole by moving the working face frame and re-cut the pressure relief groove with the protective device to deepen the pressure relief groove;

[0045] Step S110: Extend the front probe beam of the protective device into the pressure relief groove to support the roof. After the coal mining machine advances one step, repeat the above steps to complete the coal cutting.

[0046] In embodiments of the present invention, such as Figure 6 As shown, the dimensions of the pressure relief groove formed by cutting the coal wall of a high-mining fully mechanized mining face are determined. Based on the determined dimensions of the pressure relief groove, the coal wall of the high-mining fully mechanized mining face is pre-cut using a protective device to form the pressure relief groove. The forward probe beam of the protective device is extended into the pressure relief groove to support the roof, and coal is cut by the coal mining machine. The protective device is moved forward as a whole by the working face shifting frame, and the pressure relief groove is cut again using the protective device to deepen it. The forward probe beam of the protective device is extended into the pressure relief groove to support the roof, and the coal mining machine advances one step distance, and the above steps are repeated to complete the coal cutting. This achieves pressure relief of the coal wall of the high-mining fully mechanized mining face and all-time protection of the working face roof, greatly preventing the occurrence of roof falls and spalling, thereby ensuring the safety of underground workers.

[0047] Furthermore, the dimensions of the pressure relief groove are determined based on the height of the fully mechanized longwall face, the cutting depth of the coal mining machine, and the model of the hydraulic support used.

[0048] Specifically, the mining conditions of a large-scale fully mechanized longwall face are assumed to be: an average coal seam thickness of 7.16m, a working face advance length of 210m, an advance length of 794m, and a mining height of 6.8m. The working face uses a ZY17000 / 32 / 70 two-column shield hydraulic support and an MG1100 / 2985-GWD coal mining machine.

[0049] From equations (1) and (2), the effective cutting depth of the groove is determined to be 7.31 m, and the effective cutting height is 0.7 m. For example... Figure 7 As shown, by cutting a pressure relief groove with a depth of D and a height of H into the coal wall of the working face, some of the horizontal and vertical deformations are absorbed, and the forward shift of the advanced support pressure of the working face is realized, which greatly reduces the stress on the coal wall of the working face and thus reduces the possibility of spalling.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A roof fall and rib collapse protection device for a high-extraction fully mechanized mining face, characterized in that, include: The connecting seat (1) is fixedly installed on the top beam (5) of the hydraulic support; A hydraulic jack (2), the rear end of which is fixedly connected to the connecting seat (1); The front probe beam (3) is fixedly connected to the front end of the hydraulic jack (2); The cutting section (4) is provided at the front end of the front probe beam (3); The hydraulic jack (2) is used to drive the cutting part (4) to move toward or away from the coal wall of the high-extraction fully mechanized mining face through the front probe beam (3). The cutting part (4) is used to cut the coal wall at a preset position of the high-extraction fully mechanized mining face in advance to form a pressure relief groove. There are two hydraulic jacks (2), which are arranged side by side in the transverse direction and fixedly connected to the connecting seat (1) and the front probe beam (3) respectively; the two hydraulic jacks (2) work synchronously to drive the cutting part (4) to move toward or away from the coal wall of the high-mining fully mechanized mining face.

2. The roof fall and rib collapse protection device for fully mechanized mining faces with high extraction height according to claim 1, characterized in that, The front end of the top beam (5) is a box structure. The front probe beam (3) is telescopically inserted into the box structure of the top beam (5) along the length direction of the top beam (5) to share the pressure of the top plate borne by the top beam (5).

3. The roof fall and rib collapse protection device for fully mechanized mining faces with high extraction height according to claim 1, characterized in that, The rear end of the front probe beam (3) is a box structure, and the front end of the hydraulic jack (2) extends into the box structure at the rear end of the front probe beam (3) and is fixedly connected to the front probe beam (3).

4. The roof fall and rib collapse protection device for a high-extraction fully mechanized mining face according to claim 1, characterized in that, The cutting portion (4) includes: A rocker arm (41), the rear end of which is fixedly mounted on the front end of the front probe beam (3); A rotating roller (42) is rotatably mounted on the front end of the rocker arm (41); Cutting head (43), there are multiple cutting heads (43), and the multiple cutting heads (43) are arranged in a single row spiral on the rotating drum (42); A drive mechanism (44) is connected to the rotating drum (42). The drive mechanism (44) is used to drive the rotating drum (42) to rotate so as to cut the coal wall at a preset position of the high mining height fully mechanized mining face through multiple cutting heads (43).

5. The roof fall and rib collapse protection device for fully mechanized mining faces with high extraction height according to claim 4, characterized in that, The drive mechanism (44) includes a motor, a reducer and a coupling, wherein the motor drives the rotating drum (42) to rotate through the reducer and the coupling.

6. A method for protecting against roof collapse and sidewall flaring in a high-extraction fully mechanized mining face, characterized in that, The protection method employs the roof fall and rib collapse protection device for fully mechanized longwall mining faces with high mining height as described in any one of claims 1 to 5, and the protection method includes: Determine the effective cutting depth and effective height dimensions of the pressure relief groove formed by the advance cutting of the coal wall in a high-extraction fully mechanized mining face; Based on the determined dimensions of the pressure relief groove, the coal wall of the high-extraction fully mechanized mining face is pre-cut using the protective device to form the pressure relief groove, thereby effectively releasing the supporting pressure on the coal wall of the working face. The front beam of the protective device is extended into the pressure relief groove to form a full-time support for the roof. The coal is cut by the coal mining machine 3-5m behind the pressure relief groove. The frame is moved and the scraper conveyor is pushed 5m behind the coal mining machine to complete one cycle of mining process. The entire protective device is moved forward, and the pressure relief groove is re-cut by the cutting part of the protective device to deepen the pressure relief groove; The front probe of the protective device is inserted into the pressure relief groove to support the roof. After the coal mining machine advances one step, the above steps are repeated to complete the coal cutting, frame shifting, and scraper conveyor back mining process.

7. The method for protecting against roof collapse and sidewall slab fall in a fully mechanized mining face according to claim 6, characterized in that, The dimensions of the pressure relief groove are determined based on the height of the high-extraction fully mechanized mining face, the cutting depth of the coal mining machine, and the rated working resistance of the hydraulic support used.

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