Roadway type stope paste filling pre-embedded air duct ventilation device and method

Abstract

The application belongs to the technical field of stope ventilation, and discloses an access type stope paste filling pre-embedded air duct ventilation device and method. The ventilation device comprises L-shaped artificial air ducts symmetrically arranged on both sides of a panel area and on both sides of upper and lower panels. The L-shaped artificial air ducts are integrally spliced by horizontal air ducts and vertical air ducts. Four vertical air ducts are arranged at four positions of pre-embedded points 1-4, and four horizontal air ducts are connected to form an air return channel. The L-shaped artificial air duct is a circular flame-retardant PP pipe structure with a diameter of 1 m. The special shape of the L-shaped artificial air duct is designed to adapt to the special environment of the filling stope. The vertical air duct ensures that the air duct can extend from the upper layer to the lower layer, and the horizontal air duct ensures that the L-shaped artificial air duct can extend beyond the filling partition wall. Through the pre-embedded air duct ventilation structure, the problems of low ventilation efficiency of the traditional access type stope and the need for continuous follow-up of the fan to the working surface are effectively solved, the labor intensity of personnel is reduced, and the ventilation efficiency is improved.

Description

Technical Field

[0001] This application belongs to the field of mining ventilation technology, specifically relating to a ventilation device and method for pre-embedded ventilation ducts in a mining access type paste filling system. Background Technology

[0002] Ventilation in access stopes is a core aspect of mine safety, directly impacting the health and safety of workers and production efficiency. Traditional access stope ventilation technology primarily employs exhaust fans in conjunction with ventilation ducts to guide polluted air from the working face to the ore exit roadway, and then along the sluice gates into the sectional return air shafts.

[0003] Current stope ventilation primarily employs the downward-entry backfill mining method, a top-down, layered mining approach suitable for unstable ore and surrounding rock, and for mining high-grade, inclined, and steeply inclined ore bodies. However, this method presents unique technical characteristics and challenges in ventilation. Traditional downward-entry backfill mining relies on exhaust fans and ventilation ducts to guide polluted air from the working face to the ore outlet, and then along the vein into the sub-return air shaft. This method suffers from long return air routes, low ventilation efficiency, and the need for fans to continuously follow the working face, increasing the labor intensity of workers. This is particularly pronounced in high-sulfur metal mines, where difficulties in stope ventilation, high temperatures, high humidity, prolonged blasting fume emissions, and high noise levels from high-powered local ventilation fans are even more significant. Summary of the Invention

[0004] To address or partially address the problems existing in related technologies, this application provides a ventilation device and method for pre-embedded ventilation ducts in grout filling of access stopes, aiming to solve the problems of low ventilation efficiency, the need for fans to continuously follow the working face, and high labor intensity of personnel in traditional access stopes.

[0005] The first aspect of this application provides a ventilation device for pre-embedded ventilation ducts in the paste filling of an approach stope, including L-shaped artificial ventilation ducts symmetrically arranged on both sides of the panel and on both sides of the upper and lower panels; The L-shaped artificial ventilation duct is composed of horizontal and vertical ventilation ducts spliced ​​together. There are four L-shaped artificial ventilation ducts. The four vertical ventilation ducts are arranged at the four pre-embedded points 1-4 respectively. The four horizontal ventilation ducts are connected to form a return air channel. The L-shaped artificial ventilation duct is a circular flame-retardant PP pipe structure with a diameter of 1m. The special shape design of the L-shaped artificial ventilation duct is to adapt to the special environment of the backfilling mining area. The vertical ventilation duct ensures that the ventilation duct can extend from the upper layer to the lower layer, while the horizontal ventilation duct ensures that the L-shaped artificial ventilation duct can extend beyond the backfilling partition wall, providing a ventilation channel for subsequent layered mining. The distance between the horizontal air duct and the bottom plate of the empty area is 0.8-1.2m, and the outer end of the horizontal air duct extends to the outside of the filling partition wall. The bottom end of the vertical air duct is provided with a removable plug facing the bottom plate of the empty area. The bends of the horizontal and vertical air ducts are provided with arc transition structures, and the bending radius of the arc transition structure is not less than 1.5 times the diameter of the air duct. The outer wall of the L-shaped artificial air duct is covered with a polyurethane sealant layer with a thickness of not less than 2mm. Stainless steel reinforcing rings are installed at both ends of the arc transition structure and at intervals of no more than 2m on the horizontal air duct. The thickness of the stainless steel reinforcing rings is no less than 3mm. It also includes mine exhaust fans, whose outlets are connected to the exposed vertical duct ports via flame-retardant flexible joints with a length of not less than 200mm.

[0006] In one optional solution, the L-shaped artificial ventilation duct has a wall thickness of not less than 3mm, a smooth inner wall, a ventilation resistance coefficient of not more than 0.02, and flame retardant performance that meets the specifications for non-combustible materials used in mines. Flame-retardant PP pipes have excellent flame retardant properties and mechanical strength, making them suitable for use in mining environments. Flame-retardant PP pipes also have corrosion resistance and wear resistance, making them suitable for long-term use in mine filling environments. In addition, PP pipes have a low density, making them easy to transport and install, and their smooth inner wall reduces ventilation resistance and improves ventilation efficiency.

[0007] In one optional solution, the detachable plug is made of PP sheet of the same material as the L-shaped artificial air duct, with a thickness of not less than 5mm. The detachable plug is connected to the vertical air duct port through a flange. The bolt spacing of the flange is not greater than 150mm. The gasket of the flange is made of rubber sheet with a thickness of 3-5mm or closed-cell sponge rubber sheet.

[0008] In one alternative, the flame-retardant flexible joint is made of flame-retardant canvas or flame-retardant rubber, and is used to buffer the vibration generated by the operation of the mining exhaust fan.

[0009] In one optional solution, the power range of the mine exhaust fan is 5-200kW, the air volume covers 5000-50000m³ / h, and the air pressure covers 1000-5000Pa, to adapt to the ventilation needs of mining areas of different sizes.

[0010] This application also provides a ventilation method for pre-embedded ventilation ducts in grout filling of access stopes, using the aforementioned pre-embedded ventilation device for grout filling in access stopes. The method includes the following steps: S1: During the mining of the first layer of ore body, first determine the location and direction of the ventilation device, assemble and arrange L-shaped artificial ventilation ducts in the empty area, and set the L-shaped artificial ventilation ducts at four pre-embedded points on both sides of the panel and the upper and lower panels respectively. The coordinate deviation of the L-shaped artificial ventilation ducts shall not exceed 10mm, the elevation deviation shall not exceed 5mm, and the verticality deviation shall not exceed 3mm / m. S2: Install a removable plug on the side of the vertical air duct facing the bottom plate of the air area. Adjust the distance between the horizontal air duct and the bottom plate of the air area to 0.8-1.2m, so that the end of the horizontal air duct extends to a position 0.5-0.8m beyond the filling partition wall. Construct an arc transition structure and a polyurethane sealant sealing layer at the bend of the L-shaped artificial air duct and on the outer wall, respectively. Install stainless steel reinforcing rings in sequence. The L-shaped artificial air duct is now assembled. S3: Filling operation is carried out in the empty area. During the filling process, the L-shaped artificial air duct is prevented from shifting or being damaged. After the filling operation is completed, the L-shaped artificial air duct is completely fixed inside the filling body to form a pre-embedded air duct.

[0011] S4: When the second layer of ore body is being mined, the ore outlet should be arranged in a position close to the pre-embedded ventilation duct in the footwall. After the ore outlet is excavated to the position of the pre-embedded ventilation duct, the L-shaped artificial ventilation duct on the footwall side is exposed. The detachable plug at the port of the vertical ventilation duct is removed. A mine exhaust fan is installed at the port of the vertical ventilation duct using a flame-retardant flexible joint as the initial ventilation line. S5: During the subsequent mining of the ore body, the remaining L-shaped artificial ventilation ducts will be gradually exposed on the hanging wall and the mining faces on both sides. The horizontal ventilation duct ports of all exposed L-shaped artificial ventilation ducts will be connected to form return air channels during mining. The wind speed in the return air channels will be controlled at 15-20m / s. S6: After the return air duct is constructed, it will be debugged. First, the mine exhaust fan will be tested to check the bearing temperature rise and vibration parameters of the mine exhaust fan. After the debugging is completed, the return air duct will be run.

[0012] In one alternative, the filling material in step S3 is a paste with a strength grade of C20, and the 28-day compressive strength of the filling body is not less than 20 MPa.

[0013] In one alternative, during the operation of the return air duct, the air leakage rate of the return air duct is tested periodically. The test pressure is set to 1500Pa and the pressure holding time is 30 minutes, so that the air leakage rate of the return air duct is controlled within 5%.

[0014] In one alternative, the pneumatic motor of the mine exhaust fan is removed every three months, the bearings are cleaned and adequate grease is added, and all components are inspected every six months, with any damaged parts replaced promptly.

[0015] In one alternative, the bearing temperature rise parameter of the mine exhaust fan is no greater than 40℃, and the bearing vibration parameter is no greater than 5.5mm / s.

[0016] The beneficial effects of this application are: By pre-embedded ventilation ducts, the problems of low ventilation efficiency and the need for continuous fan operation in traditional access mining areas are effectively solved, reducing the labor intensity of personnel and improving ventilation efficiency. The design adopts an L-shaped flame-retardant PP artificial ventilation duct, which pre-embeds ventilation channels during the filling process, providing a stable ventilation path for subsequent multi-layer and layered mining, and avoiding the problem of frequent movement of ventilation ducts in traditional ventilation methods. By symmetrically arranging pre-embedded air ducts in multiple locations within the panel, a complete ventilation circuit can be quickly formed, improving the stability and reliability of the ventilation system, effectively improving the working environment in the mining area, and significantly shortening the duration of blasting smoke emission. The method of this invention is applicable to the down-entry backfilling mining method, especially in high-sulfur metal mines, and can effectively solve problems such as difficult ventilation in the stope, high temperature, high humidity, long blasting smoke emission time, and high noise from high-power local ventilation fans.

[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the working state of the ventilation system in one embodiment of this application; Figure 2 This is a plan view of the pre-embedded air duct layout formed by the L-shaped artificial air duct in one embodiment of this application; Figure 3 This is a schematic diagram of the structure of an L-shaped artificial air duct in one embodiment of this application.

[0020] The following are the labels in the attached diagram: 1-First layer of ore body; 2-Second layer of ore body; 3-L-shaped artificial ventilation duct; 4-Removable plug; 5-Horizontal ventilation duct; 6-Vertical ventilation duct; 7-Infilled partition wall; 8-Mine exhaust fan; 9-Flame-retardant flexible joint; 10-Exit duct; 11-Return air duct; 12-Stainless steel reinforcing ring; 13-Polyurethane sealant sealing layer; 14-Arc transition structure. Detailed Implementation

[0021] The specific embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application. Similarly, the following examples are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0024] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0025] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0026] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0027] Traditional down-entry backfilling mining methods have long relied on exhaust fans and ventilation ducts to guide polluted air from the working face to the ore outlet, and then along the vein into the sectional return air shafts. This method suffers from long return air routes, low ventilation efficiency, and the need for fans to continuously follow the working face, increasing the labor intensity of workers. This is especially true in high-sulfur metal mines, where problems such as difficult stope ventilation, high temperature, high humidity, long blasting fume emission time, and high noise from high-power local ventilation fans are even more pronounced.

[0028] To address the aforementioned problems, this application proposes improvements and innovations, including the following embodiments.

[0029] Example 1 In one implementation, see Figures 1-3 This application provides a ventilation device for pre-embedded ventilation ducts in the paste filling of an approach stope, including L-shaped artificial ventilation ducts 3 symmetrically arranged at four pre-embedded points on both sides of the panel and the upper and lower panels, forming a symmetrical arrangement to ensure the balance of the ventilation system. The L-shaped artificial ventilation duct 3 is composed of a horizontal ventilation duct 5 and a vertical ventilation duct 6. The L-shaped artificial ventilation duct 3 is a circular flame-retardant PP pipe structure with a diameter of 1m. The special shape design of the L-shaped artificial ventilation duct 3 is to adapt to the special environment of the filling mining area. The vertical ventilation duct 6 ensures that the ventilation duct can extend from the upper layer to the lower layer, while the horizontal ventilation duct 5 ensures that the L-shaped artificial ventilation duct 3 can extend beyond the filling partition wall 7, providing a ventilation channel for subsequent layered mining.

[0030] The horizontal air duct 5 is 1m away from the bottom plate of the empty area, and the outer end of the horizontal air duct 5 extends to the outside of the filling partition wall 7. The bottom end of the vertical air duct 6 is provided with a detachable plug 4 facing the bottom plate of the empty area. The bend of the horizontal air duct 5 and the vertical air duct 6 is provided with an arc transition structure 14. The bending radius of the arc transition structure 14 is not less than 1.5 times the diameter of the air duct to reduce local resistance. The outer wall of the L-shaped artificial air duct 3 is covered with a polyurethane sealant layer 13, the thickness of which is not less than 2mm.

[0031] Stainless steel reinforcing rings 12 are provided at both ends of the arc transition structure 14 and at intervals of no more than 2m on the horizontal air duct 5. The thickness of the stainless steel reinforcing rings 12 is not less than 3mm, which enhances the structural stability of the air duct. It also includes a mine exhaust fan 8, the outlet of which is connected to the exposed vertical duct 6 via a flame-retardant flexible joint 9 with a length of not less than 200mm.

[0032] In some implementations, see Figure 2 There are four L-shaped artificial air ducts 3. The four vertical air ducts 6 are arranged at the four pre-buried points 1-4 respectively. The four horizontal air ducts 5 are connected to form the return air channel 11. After the L-shaped artificial air ducts 3 are exposed, all the horizontal air ducts 5 are connected to form a ventilation system.

[0033] In some implementations, see Figure 3 The L-shaped artificial ventilation duct 3 has a wall thickness of not less than 3mm, a smooth inner wall, and a ventilation resistance coefficient of not more than 0.02. Its flame retardant performance meets the specifications for the use of non-combustible materials in mines. Flame retardant PP pipes have excellent flame retardant properties and mechanical strength, making them suitable for use in mining environments. Flame retardant PP pipes also have corrosion resistance and wear resistance, making them suitable for long-term use in mine filling environments. In addition, PP pipes have a low density, making them easy to transport and install. At the same time, their smooth inner wall can reduce ventilation resistance and improve ventilation efficiency.

[0034] The detachable plug 4 is made of the same PP board as the L-shaped artificial air duct 3, with a thickness of not less than 5mm. The detachable plug 4 is connected to the port of the vertical air duct 6 through a flange. The bolt spacing of the flange is not greater than 150mm. The gasket of the flange is made of rubber sheet with a thickness of 3-5mm or closed-cell sponge rubber sheet.

[0035] In some implementations, see Figure 1 , Figure 3 The flame-retardant flexible joint 9 is made of flame-retardant canvas or flame-retardant rubber. The flame-retardant flexible joint 9 is used to buffer the vibration generated by the operation of the mining exhaust fan 8.

[0036] The power range of the mine exhaust fan 8 is 5-200kW, the air volume covers 5000-50000m³ / h, and the air pressure covers 1000-5000Pa, which can be used to adapt to the ventilation needs of mining areas of different sizes.

[0037] Example 2 Corresponding to the aforementioned Embodiment 1, this embodiment also provides a ventilation method for pre-embedded ventilation ducts in grout filling of an access stope, using the grout filling pre-embedded ventilation device from Embodiment 1. The method includes the following steps: S1: During the mining of the first layer of ore body 1, the location and direction of the ventilation device are first determined according to the design drawings. The device is precisely positioned using measuring instruments to ensure that the coordinate deviation does not exceed 10mm, the elevation deviation does not exceed 5mm, and the verticality deviation does not exceed 3mm / m. The L-shaped artificial ventilation duct 3 is assembled and arranged in the goaf. The L-shaped artificial ventilation duct 3 is set on both sides of the panel and on both sides of the upper and lower panels. The horizontal ventilation duct 5 and the vertical ventilation duct 6 are connected by flanges. When connecting the flanges, the bolt spacing is 120mm. S2: Install a removable plug 4 on the side of the vertical air duct 6 facing the bottom plate of the empty area through a flange. Adjust the distance between the horizontal air duct 5 and the bottom plate of the empty area to 1m, so that the end of the horizontal air duct 5 extends to a position 0.5-0.8m beyond the filling partition wall 7. Construct an arc transition structure 14 and a polyurethane sealant sealing layer 13 at the bend of the L-shaped artificial air duct 3 and on the outer wall, respectively. Install stainless steel reinforcing rings 12 in sequence. The L-shaped artificial air duct 3 is assembled and sealed. Apply sealant to the seam between the horizontal air duct 5 and the vertical air duct 6 and the flange edge to ensure good sealing at the connection. S3: Filling operation is carried out in the empty area. The filling material is paste with a strength grade of C20. The 28-day compressive strength of the filling body is not less than 20MPa. During the filling process, prevent the L-shaped artificial air duct 3 from shifting or being damaged. After the filling operation is completed, the L-shaped artificial air duct 3 is completely fixed inside the filling body to form a pre-embedded air duct.

[0038] S4: When the second stratified ore body 2 is being mined, the ore outlet 10 should be preferentially positioned near the pre-embedded ventilation duct in the footwall. After the ore outlet 10 is excavated to the pre-embedded ventilation duct position, the L-shaped artificial ventilation duct 3 on the footwall side should be exposed. The detachable plug 4 at the port of the vertical ventilation duct 6 should be removed. Special tools should be used during the removal process to avoid damaging the vertical ventilation duct 6. At the port of the vertical ventilation duct 6, a mine exhaust fan 8 should be installed as the initial ventilation line through a flame-retardant flexible joint 9. The cross-sectional dimensions of the flame-retardant flexible joint 9 should be consistent with the air inlet and outlet of the fan to ensure a tight and leak-free connection. The mine exhaust fan 8 is an FQCNo4.0 mine exhaust pneumatic fan with an air volume of 2 m³ / s (7200 m³ / h), an air pressure of 750 Pa, an air supply pressure of 0.45 MPa, an air consumption of 0.090 m³ / s, a speed of 3000 r / min, and an impeller diameter of 400 mm. Before installing the mine exhaust fan 8, check the foundation concrete strength to ensure it reaches more than 80% of the design value, and the surface flatness deviation is ≤5mm / m. The position deviation of the pre-embedded bolts is ≤2mm. When the mine exhaust fan 8 is in place, the longitudinal and transverse horizontal deviations are ≤0.1mm / m. Do not forcefully hammer the anchor bolts during insertion; the gap between the bolts and the hole wall should be uniform. The controller of the mine exhaust fan 8 is located in the upper connecting roadway for easy operation and maintenance. S5: During the subsequent mining of the ore body, the remaining L-shaped artificial ventilation channels 3 will be gradually exposed on the hanging wall and the mining faces on both sides. The horizontal ventilation channel 5 ports of all exposed L-shaped artificial ventilation channels 3 will be connected to form the return air channel 11 during mining. The wind speed in the return air channel 11 will be controlled at 15-20m / s. S6: After the return air duct 11 is constructed, it will be debugged. First, the mine exhaust fan 8 will be tested to check the bearing temperature rise and vibration parameters of the mine exhaust fan 8. The bearing temperature rise parameter of the mine exhaust fan 8 should not exceed 40℃, and the bearing vibration parameter should not exceed 5.5mm / s. After the debugging is completed, the return air duct 11 will be put into operation. The air leakage test of the return air duct 11 will be carried out regularly. The test pressure is set to 1500Pa and the pressure holding time is 30 minutes. The air leakage rate of the return air duct 11 should be controlled within 5%. The pneumatic motor of the mine exhaust fan 8 will be removed every three months, the bearings will be cleaned and sufficient grease will be added, and all parts will be inspected every six months. If any damage is found, it will be replaced in time.

[0039] The main technical parameters of the ventilation system are shown in the table below: Implementation Results: Compared with traditional ventilation methods, the pre-embedded air duct ventilation method in this embodiment has the following advantages: 1. High ventilation efficiency: The pre-embedded air duct forms a stable ventilation channel with low ventilation resistance and minimal air volume loss, improving ventilation efficiency by 35% compared to traditional methods.

[0040] 2. Low labor intensity: The fan does not need to continuously follow the work surface, reducing the workload of equipment movement and adjustment, and the labor intensity is reduced by 60% compared with the traditional method.

[0041] 3. Good system stability: The pre-embedded air duct is fixed in the filling body, which is not easy to be damaged. The system operates stably and the failure rate is reduced by 70% compared with the traditional method.

[0042] 4. Improved working environment: Effectively reduced temperature, humidity and noise in the mining area, improved the working environment, and enhanced worker comfort and safety.

[0043] This application may also have other variations. For example, the artificial air duct can be made of other materials, such as stainless steel plate, fiberglass, etc.; the cross-sectional shape of the air duct can be circular, elliptical or rectangular; the number and location of the air ducts can be adjusted according to actual needs; the fan type can be axial flow fan, centrifugal fan, etc.; the ventilation system can be equipped with monitoring and control equipment to achieve intelligent management.

[0044] Finally, it should be noted that although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application, all of which should be included within the protection scope of this application.

Claims

1. A ventilation device for pre-embedded ventilation ducts in a stope with a feedstock filling system, characterized in that, Including L-shaped artificial air ducts symmetrically arranged on both sides of the panel area and on both sides of the upper and lower panels (3); The L-shaped artificial air duct (3) is composed of horizontal air duct (5) and vertical air duct (6) spliced ​​together. There are four L-shaped artificial air ducts (3). The four vertical air ducts (6) are respectively arranged at the four pre-embedded points 1-4. The four horizontal air ducts (5) are connected to form a return air channel (11). The distance between the horizontal air duct (5) and the bottom plate of the empty area is 0.8-1.2m, and the outer end of the horizontal air duct (5) extends to the outside of the filling partition wall (7). The bottom end of the vertical air duct (6) is provided with a detachable plug (4) facing the bottom plate of the empty area. The bend of the horizontal air duct (5) and the vertical air duct (6) is provided with an arc transition structure (14). The bending radius of the arc transition structure (14) is not less than 1.5 times the diameter of the air duct. The outer wall of the L-shaped artificial air duct (3) is covered with a polyurethane sealant sealing layer (13), and the thickness of the polyurethane sealant sealing layer (13) is not less than 2 mm. Stainless steel reinforcing rings (12) are provided at both ends of the arc transition structure (14) and at intervals of no more than 2m on the horizontal air duct (5). The thickness of the stainless steel reinforcing rings (12) is not less than 3mm. It also includes a mine exhaust fan (8), the outlet of which is connected to the exposed port of the vertical duct (6) via a flame-retardant flexible joint (9) with a length of not less than 200 mm.

2. The ventilation device for pre-embedded ventilation ducts in the paste filling of the access stope according to claim 1, characterized in that: The L-shaped artificial air duct (3) is a circular flame-retardant PP pipe structure with a diameter of 1m. The wall thickness of the L-shaped artificial air duct (3) is not less than 3mm, the inner wall is smooth, and the ventilation resistance coefficient is not greater than 0.

02.

3. The ventilation device for pre-embedded ventilation ducts in the paste filling of the access stope according to claim 2, characterized in that: The detachable plug (4) is made of PP board of the same material as the L-shaped artificial air duct (3), with a thickness of not less than 5mm. The detachable plug (4) is connected to the port of the vertical air duct (6) through a flange. The bolt spacing of the flange is not greater than 150mm. The gasket of the flange is a closed-cell sponge rubber sheet with a thickness of 3-5mm.

4. The ventilation device for pre-embedded ventilation ducts in the paste filling of the access stope according to claim 1, characterized in that: The flame-retardant flexible joint (9) is made of flame-retardant canvas or flame-retardant rubber material. The flame-retardant flexible joint (9) is used to buffer the vibration generated by the operation of the mining exhaust fan (8).

5. The ventilation device for pre-embedded ventilation ducts in the paste filling of the access stope according to claim 4, characterized in that: The power range of the mining exhaust fan (8) is 5-200kW, the air volume is 5000-50000m³ / h, and the air pressure is 1000-5000Pa.

6. A method for ventilation of pre-embedded ventilation ducts in a roadway-type stope with paste filling, characterized in that: The method of using the pre-embedded ventilation duct for paste filling in the access stope as described in any one of claims 1-5 includes at least the following steps: S1: During the mining of the first layer of ore body (1), first determine the location and direction of the ventilation device, assemble and arrange the L-shaped artificial ventilation duct (3) in the empty area, and set the L-shaped artificial ventilation duct (3) at the four pre-embedded points on both sides of the panel and the upper and lower panels respectively. The coordinate deviation of the L-shaped artificial ventilation duct (3) shall not exceed 10mm, the elevation deviation shall not exceed 5mm, and the verticality deviation shall not exceed 3mm / m. S2: Install a removable plug (4) on the side of the vertical air duct (6) facing the bottom plate of the empty area, adjust the distance between the horizontal air duct (5) and the bottom plate of the empty area to 0.8-1.2m, so that the end of the horizontal air duct (5) extends to a position 0.5-0.8m beyond the filling partition wall (7), construct the arc transition structure (14) and the polyurethane sealant sealing layer (13) at the bend of the L-shaped artificial air duct (3) and the outer wall respectively, and install the stainless steel reinforcing ring (12) in sequence. The L-shaped artificial air duct (3) is assembled. S3: Filling operation is carried out in the empty area. During the filling process, the L-shaped artificial air duct (3) is prevented from shifting or being damaged. After the filling operation is completed, the L-shaped artificial air duct (3) is completely fixed inside the filling body to form a pre-embedded air duct. S4: When the second layer of ore body (2) is being mined, the ore outlet (10) is arranged in a position close to the pre-embedded ventilation duct in the lower plate. After the ore outlet (10) is excavated to the position of the pre-embedded ventilation duct, the L-shaped artificial ventilation duct (3) on the lower plate side is exposed. The detachable plug (4) at the port of the vertical ventilation duct (6) is removed. A mine exhaust fan (8) is installed at the port of the vertical ventilation duct (6) through a flame-retardant flexible joint (9) as the initial ventilation line. S5: During the subsequent mining of the ore body, the remaining L-shaped artificial ventilation ducts (3) are gradually exposed in the upper plate and the mining faces on both sides. The horizontal ventilation ducts (5) ports of all exposed L-shaped artificial ventilation ducts (3) are connected to form the return air passage (11) during mining. The wind speed in the return air passage (11) is controlled at 15-20m / s. S6: After the return air duct (11) is constructed, it is debugged. First, the mine exhaust fan (8) is tested and the bearing temperature rise and vibration parameters of the mine exhaust fan (8) are checked. After the debugging is completed, the return air duct (11) is run.

7. A ventilation method for pre-embedded ventilation ducts in a roadway-type stope with paste filling according to claim 6, characterized in that: In step S3, the filling material is a paste with a strength grade of C20, and the 28-day compressive strength of the filling body is not less than 20 MPa.

8. A ventilation method for pre-embedded ventilation ducts in a roadway-type stope with paste filling according to claim 6, characterized in that: During the operation of the return air duct (11), the air leakage test of the return air duct (11) is carried out regularly. The test pressure is set to 1500Pa and the pressure holding time is 30 minutes. The air leakage rate of the return air duct (11) is controlled within 5%.

9. A ventilation method for pre-embedded ventilation ducts in a roadway-type stope with paste filling according to claim 6, characterized in that: Every three months, the pneumatic motor of the mining exhaust fan (8) should be removed, the bearings cleaned and lubricated. Every six months, all parts should be inspected and replaced if any damage is found.

10. A ventilation method for pre-embedded ventilation ducts in a feedstock-type stope according to claim 6, characterized in that: The bearing temperature rise parameter of the mining exhaust fan (8) is not greater than 40℃, and the bearing vibration parameter is not greater than 5.5mm / s.

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