A mixed arrangement method for a roadway in an acute-inclined coal seam based on gob-side entry retaining

Abstract

The present application belongs to the technical field of coal mining, and discloses a kind of steeply inclined coal seam roadway mixed arrangement method based on gob-side entry retaining, each working face return air crossheading is arranged in coal seam, and transport crossheading is arranged in the overburden of coal seam, to form working face open-off cut with reduced inclination angle relative to coal seam, comprising the following steps: S1, determine working face parameters;S2, after the first working face excavation work is completed, start installation and mining, and start excavating the second working face in turn;S3, after the second working face open-off cut excavation is completed, calculate the anti-excavation safety distance and the starting point of the first working face gob-side entry retaining;S4, when the first working face mining reaches the starting point of the gob-side entry retaining, start gob-side entry retaining;When the second working face return air crossheading excavates to the anti-excavation safety distance, cut into the starting point of the first working face gob-side entry retaining through the connecting roadway.The present application can improve mining efficiency and safety.

Description

Technical Field

[0001] This invention belongs to the field of coal mining technology, specifically relating to a mixed layout method of steeply inclined coal seam roadways based on gob-side roadway retention, which improves mining efficiency by combining the small coal pillars left for the replacement working face with the gob-side roadway retention. Background Technology

[0002] Small pillar and pillarless mining represent the current technological development direction of coal mining. However, due to the significant complexity and difficulty of mining steeply inclined coal seams, large pillar roadway protection technology is still widely used, resulting in a substantial waste of coal resources. Therefore, reducing pillar size and achieving high recovery rates in steeply inclined coal seam mining is of great significance for the high-quality development of my country's coal industry.

[0003] Steeply inclined coal seams are mostly mined using the strike-longwall mining method, with a single-wing sequential layout. This method requires large coal pillars to ensure the stability of adjacent working face roadways and the safe succession of each working face. Reducing the width of the coal pillars under single-wing sequential mining conditions in steeply inclined coal seams can improve coal recovery. However, if traditional small coal pillar mining is used, steeply inclined working faces are prone to roadway deformation and small coal pillar instability and collapse under mining pressure. Therefore, it is necessary to avoid the influence zone of the upper working face. In the field, this is generally achieved through reverse excavation. However, the face position of the reverse excavation face needs to lag behind the position of the upper working face, and time is also required to wait for the overlying strata in the goaf of the upper working face to stabilize. In this case, the working face needs to be shut down to wait for the roadway reverse excavation to be completed, resulting in mining suspension and huge losses.

[0004] One solution is to use gob-side roadway retention. However, due to the excessive dip angle of the steeply inclined coal seam, the stratum of the transport roadway during mining needs to be raised to prevent slippage of the equipment on the steeply inclined working face. While gob-side roadway retention solves the problem of slippage of the working face equipment, it also requires the mining of a large amount of rock, increasing the mining difficulty, increasing the gangue content and washing difficulty, and reducing the coal quality.

[0005] To address the aforementioned problems in the mining of steeply inclined coal seams, a new mining method is needed. Summary of the Invention

[0006] In order to reduce the difficulty of mining steeply inclined coal seams, improve mining efficiency and safety in existing technologies, this invention proposes a method for mixed roadway layout of steeply inclined coal seams, which combines the arrangement of small coal pillars left in the successor working face with roadway retention along the goaf. This reduces the impact of mining activity caused by the previous working face during mining on the tunneling of the next working face, increases the resource recovery rate, and reduces the amount of useless work in tunneling through the rock strata.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a mixed layout method for steeply inclined coal seam roadways based on goaf retention, wherein the return airway of each working face is arranged in the coal seam, and the transport roadway is arranged in the overlying strata of the coal seam, so as to form a working face cut-off with a reduced dip angle relative to the coal seam, including the following steps:

[0008] S1. Determine the strike length, dip length, working face recovery rate, tunneling speed of the tunneling machine, stability distance affected by mining, and working face installation time;

[0009] S2. After the excavation of the first working face is completed, the installation and mining of the first working face will begin, and the excavation of the second working face transport roadway and the second working face cut-out will begin in sequence.

[0010] S3. After the second working face is cut and excavated, determine whether the first working face needs to leave a roadway along the gob. If yes, calculate the safe distance for reverse excavation and the starting point of the roadway along the gob of the first working face, and proceed to step S4; if no, directly excavate and connect the return airway of the second working face.

[0011] S4. When the first working face is mined back to the starting point of the gob-side roadway, the gob-side roadway is started; at the same time, when the return airway of the second working face is excavated to the safe distance of the reverse excavation, it is obliquely excavated into the starting point of the gob-side roadway of the first working face through the connecting roadway, and then the tunneling machine of the second working face leaves the working face through the transport roadway of the first working face.

[0012] S5. After the first working face is completed, the second working face is started to be mined. At the same time, the tunneling machine returns to the second working face and the return air roadway of the second working face is tunneled through.

[0013] In step S3, the formula for calculating the reverse excavation safety distance is:

[0014] ;

[0015] in, l 1 represents the mining distance of the first working face, k represents the stable distance affected by mining, vmining represents the mining speed of the working face, and vtunneling represents the tunneling speed of the tunneling machine.

[0016] The formula for calculating the mining distance of the first working face is:

[0017] l 1= v Pick [( l + b ) / v dig- t 0)];

[0018] in, lt0 represents the length of the working face, b represents the inclination width of the working face, and t0 represents the installation time of the working face.

[0019] The starting point of the roadway along the goaf is determined by the safe distance of reverse excavation and the inclination of the coal seam.

[0020] In step S3, the criterion for determining whether or not to leave a roadway along the goaf is:

[0021] ;

[0022] in, l The length of the working face is represented by , and k represents the stability distance affected by mining activities. l 1 indicates the mining distance of the first working face.

[0023] The aforementioned method for mixed layout of steeply inclined coal seam roadways based on goaf retention further includes the following steps:

[0024] S6. Repeat steps S2 to S5 to excavate the third working face, while the second working face continues to be mined. Repeat the cycle until all working faces are mined.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. This invention proposes a mixed layout method for steeply inclined coal seam roadways based on gob-side roadway retention. By combining the placement of small coal pillars for the replacement working face with gob-side roadway retention, the method achieves a reasonable layout of roadway location and timing. It avoids the impact of mining stress on the small coal pillars protecting the roadways in steeply inclined coal seams, while reducing the time required for the mining stress caused by the previous working face to dissipate before the next working face is excavated. This solves the problem of waiting for roadway reverse excavation after coal mining work is stopped, and increases work efficiency.

[0027] 2. This invention can reduce the dip angle of the working face roadway in the dip direction under the condition of steeply inclined coal seams, making mining operations safer.

[0028] 3. This invention can increase the resource extraction rate of coal mines, while reducing the workload within rock strata and improving economic efficiency. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the working face roadway layout in an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the process flow for arranging the tunneling direction of the second working face in an embodiment of the present invention;

[0031] Figure 3 for Figure 1 Cross-sectional view of AA in the middle;

[0032] Figure 4for Figure 1 Cross-sectional view of BB in the middle;

[0033] Figure 5 for Figure 1 Cross-sectional view of CC.

[0034] In the diagram: 1-Stop mining line, 2-Return airway of the first working face, 3-Transport roadway of the first working face, 4-First working face, 5-Goaf roadway of the first working face, 6-Goaf area, 7-Return airway of the second working face, 8-Second working face, 9-Tunneling direction of the tunneling machine, 10-Transport roadway of the second working face, 11-Cut-out of the second working face, 12-Third working face, 13-Connecting roadway. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] like Figures 1-5 As shown, this embodiment of the invention provides a mixed layout method for steeply inclined coal seam roadways based on gob-side roadway retention. The return air roadway of each working face is arranged in the coal seam, and the transport roadway is arranged in the overlying strata of the coal seam, forming a working face cut-off with a decreasing dip angle relative to the coal seam. In each working face, a roadway with a gradually decreasing dip angle towards the strike of the coal seam is formed. Then, through a downwardly advancing roadway, the transport roadway of the next working face will return to the coal seam for arrangement. Wherein, 1 represents the stop line, 2 represents the return air roadway of the first working face, 3 represents the transport roadway of the first working face, 4 represents the first working face, 5 represents the gob-side roadway of the first working face, 6 represents the goaf, 7 represents the return air roadway of the second working face, 8 represents the second working face, 9 represents the tunneling direction of the tunneling machine, 10 represents the transport roadway of the second working face, 11 represents the cut-off of the second working face, 12 represents the third working face, and 13 represents the connecting roadway. The specific steps include:

[0037] Step S1: Determine the strike length, dip length, working face recovery rate, tunneling speed of the tunneling machine, stability distance affected by mining, and working face installation time;

[0038] In this embodiment, the strike length l of the coal mine working face is 1400m, the dip length b is 200m, the working face mining speed vmin is 54m / d, the tunneling speed vt is 10m / d, the safe range of mining-induced impact k is 100m, and the working face installation time t0 is 60d.

[0039] Step S2: After the excavation of the first working face is completed, installation and mining of the first working face begin, and simultaneously, excavation of the second working face transport roadway 10 and the second working face cutter 11 begins sequentially. For example... Figure 2 As shown in (a), this is a schematic diagram of the second working face 8 excavating to the second working face cut-out 11.

[0040] Step S3: After the second working face cut-in 11 is completed, determine whether the first working face needs to leave a roadway along the goaf. If so, calculate the safe distance for reverse excavation and the starting point of the roadway along the goaf of the first working face, and proceed to step S4; if not, directly excavate and connect the return airway 7 of the second working face.

[0041] In step S3, the criterion for determining whether or not to leave a roadway along the goaf is:

[0042] ; (1)

[0043] in, l The length of the working face is represented by , and k represents the stability distance affected by mining activities. l 1 indicates the mining distance of the first working face.

[0044] In this embodiment, the time required for the second working face 8 to excavate the transport roadway 10 and the second working face cut-out 11 is... t 1 is:

[0045] t 1 = ( l + b ) / v Digging = 160d; (2)

[0046] Then the distance l1 through the first working face 4 is:

[0047] l 1= v Pick ( t 1- t 0) = 400m; (3)

[0048] The criteria for substituting the calculated data into equation (1) include:

[0049] ; (4)

[0050] Therefore, if the criteria are met, it is necessary to leave a roadway along the goaf in the first working face.

[0051] To ensure that the return air roadway 7 of the second working face is not affected by the mining activity of the first working face 4, the maximum reverse tunneling distance is: the distance from the cut-in 11 of the second working face to the tunneling face of the return air roadway 7. Therefore, based on the mining and tunneling speed vmining, vtunneling, and the stable distance affected by mining activity k, the safe reverse tunneling distance can be calculated. l 2:

[0052] l 2= = 600m; (5)

[0053] Step S4: When the first working face is back-mined to the starting point of the gob-side roadway, the gob-side roadway is started; at the same time, when the return airway 7 of the second working face is excavated to the safe distance of reverse excavation, it is obliquely excavated into the starting point of the gob-side roadway 5 of the first working face through the connecting roadway 13, and then the tunneling machine of the second working face leaves the working face through the transport roadway 3 of the first working face.

[0054] like Figure 2 As shown in (b), this is a schematic diagram of the second working face 8 when it has reached the safe distance for reverse excavation. Figure 2 As shown in (c), this is a schematic diagram of the starting point of the goaf retainer 5, which is obliquely excavated from the return air roadway 7 of the second working face into the first working face via the connecting roadway 13. At this time, full negative pressure ventilation of the second working face 8 can be achieved.

[0055] Specifically, in this embodiment, the starting point of the gob-side roadway is determined by the reverse excavation safety distance and the coal seam dip. The starting point of the gob-side roadway is ahead of the reverse excavation safety distance. l 3 places, l The specific value of 3 is determined based on the coal seam inclination and the distance between the second working face return air roadway 7 and the first working face transport roadway.

[0056] Step S5: After the first working face is completed, the second working face is started to be mined. At the same time, the tunneling machine returns to the second working face and tunnels through the return air roadway 7 of the second working face.

[0057] Before mining the second working face 8, supports, coal mining machines, scraper conveyors, etc. need to be installed. After installation, the overlying rock movement of the first working face 4 is stable, and forward excavation of the return air roadway 7 of the second working face can begin. When the roadway is cleared, the connecting roadway between the gob-side retainer 5 and the small coal pillar is blocked. At this time, the gob-side retainer 5 is ventilated by a local ventilation fan until it is abandoned.

[0058] Step S6: Repeat steps S3 to S5 to continue mining the second working face, and arrange the working face in the same way for the third working face; repeat the cycle until all working faces are mined.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for mixed layout of steeply inclined coal seam roadways based on goaf retention, characterized in that, The return air roadway of each working face is arranged in the coal seam, and the transport roadway is arranged in the overlying strata of the coal seam to form a working face cut-off with a reduced dip angle relative to the coal seam, including the following steps: Step S1: Determine the strike length, dip length, working face recovery rate, tunneling speed of the tunneling machine, stability distance affected by mining, and working face installation time; Step S2: After the excavation of the first working face is completed, the installation and mining of the first working face will begin, and at the same time, the excavation of the second working face transport roadway (10) and the second working face cut-out (11) will begin in sequence. Step S3: After the second working face cut (11) is completed, determine whether the first working face needs to leave a roadway along the gob. If yes, calculate the safe distance for reverse excavation and the starting point of the roadway along the gob of the first working face, and proceed to step S4. If no, directly excavate and connect the return airway (7) of the second working face. The starting point of the roadway along the gob is determined by the safe distance for reverse excavation and the inclination of the coal seam. Step S4: When the first working face is back-mined to the starting point of the gob-side roadway, the gob-side roadway is started; at the same time, when the return air roadway (7) of the second working face is excavated to the safe distance of the reverse excavation, it is obliquely excavated into the starting point of the gob-side roadway of the first working face through the connecting roadway (13), and then the tunneling machine of the second working face leaves the working face through the transport roadway (3) of the first working face. Step S5: After the first working face is mined, the second working face is mined. At the same time, the tunneling machine returns to the second working face and tunnels through the return air roadway (7) of the second working face. In step S3, the criterion for determining whether or not to leave a roadway along the goaf is: ； in, l The length of the working face is represented by , and k represents the stability distance affected by mining activities. l 1 indicates the mining distance of the first working face; In step S3, the formula for calculating the reverse excavation safety distance is: ； in, l 1 represents the mining distance of the first working face, k represents the stabilization distance affected by mining, and v 采 v represents the working face mining speed. 掘 This indicates the tunneling speed of the tunneling machine.

2. The method for mixed layout of steeply inclined coal seam roadways based on goaf retention according to claim 1, characterized in that, The formula for calculating the mining distance of the first working face is: l 1= v 采 [（ l + b ） / v 掘 - t 0）]； in, l t0 represents the length of the working face, b represents the inclination width of the working face, and t0 represents the installation time of the working face.

3. The method for mixed layout of steeply inclined coal seam roadways based on goaf retention according to claim 1, characterized in that, It also includes the following steps: Step S6: Repeat steps S2 to S5 to excavate the third working face while the second working face continues to be mined. Repeat the cycle until all working faces are mined.

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