Mining method of fully mechanized coal mining face containing dirt band layer

Abstract

The invention belongs to the technical field of coal mining, and particularly discloses a mining method of a fully mechanized coal mining face containing a dirt band layer. The mining method of the fully mechanized coal mining face containing the dirt band layer comprises the following steps that at least two roadways are constructed in a coal seam in the first direction at intervals; a first drill hole is constructed in the coal seam between every two adjacent roadways in the second direction, the first drill holes are connected with the roadways, and the first direction and the second direction are orthogonal; fracturing fluid is injected into the first drill hole; a second drill hole is constructed in the coal seam between every two adjacent roadways in the second direction, the second drill holes are connected with the roadways, and blasting is conducted through the second drill holes; a third drill hole is constructed in the gangue of the coal face in the coal seam between the two adjacent roadways in the first direction, and blasting is conducted through the third drill hole; and mining the coal seam. The mining difficulty can be reduced, the mining efficiency is improved, and potential safety hazards are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mining, and in particular relates to a mining method for a fully mechanized mining face containing intercalated gangue layers. Background Art

[0002] In coal mining, as the mining depth increases, the difficulty of mining also increases. For natural coal seams, the ignition cycle of the working face is short and the fire prevention and extinguishing pressure is high. During the mining of the working face, the hard interlayer within the mining height range becomes an important hidden danger restricting the safe production of mines. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, an embodiment of the present invention proposes a mining method for a fully mechanized mining face containing interlayer gangue, which can reduce the mining difficulty, improve the mining efficiency, and reduce safety hazards.

[0004] The mining method of a fully-mechanized mining face containing interbedded gangue layers according to an embodiment of the present invention comprises the following steps: constructing at least two tunnels spaced apart along a first direction in a coal seam; constructing a first borehole along a second direction in the coal seam between two adjacent tunnels, the first borehole being connected to the tunnel, and the first direction and the second direction being orthogonal; injecting fracturing fluid into the first borehole; constructing a second borehole along the second direction in the coal seam between two adjacent tunnels, the second borehole being connected to the tunnel, and blasting is performed using the second borehole; constructing a third borehole along the first direction on the gangue of the coal mining face in the coal seam between the two adjacent tunnels, and blasting is performed using the third borehole; and mining the coal seam.

[0005] It can be understood that by constructing a second borehole and injecting fracturing fluid into the coal seam, the fracturing fluid enters the tiny cracks and pores of the gangue, which can reduce the hardness of the gangue in the coal seam and make the gangue easier to break. Then, a second borehole is constructed in the coal seam, and blasting is performed using the second borehole to break the gangue into smaller pieces. In addition, a third borehole is constructed on the gangue at the coal mining face, and targeted blasting is performed on the gangue, which can further improve the crushing effect of the gangue and reduce the working resistance of the coal mining machine, which is beneficial to improving the mining efficiency during coal mining, thereby reducing safety hazards. In addition, injecting fracturing fluid into the coal seam before blasting can increase the area of ​​broken gangue, reduce the amount of explosives used, and reduce the dust generated during blasting.

[0006] In this embodiment, after the fracturing fluid is injected into the first borehole for a preset time, the second borehole is used for blasting.

[0007] In this embodiment, the preset time is 7 to 10 days.

[0008] In this embodiment, the second borehole is constructed in multiple cycles and blasting is performed using the second borehole.

[0009] In this embodiment, a plurality of second boreholes are constructed at intervals along the first direction each time, and each second borehole constructed in a subsequent construction is located between two adjacent second boreholes constructed previously.

[0010] In this embodiment, a plurality of the third bore holes are provided, and the plurality of the third bore holes are evenly spaced and distributed.

[0011] In this embodiment, within the projection in the first direction, a preset distance is provided between the boundary of the gangue and the adjacent third borehole.

[0012] In this embodiment, when the coal seam is a steeply inclined coal seam, the coal mining face is adjusted to a pseudo-inclined state for mining by making the height of the return air roadway higher than the transport roadway and the transport roadway ahead of the return air roadway.

[0013] In this embodiment, after the coal mining machine of the coal mining working face cuts a piece of coal, the front chute is pushed in the order from the front chute head to the tail of the machine; and / or, after each rear chute finishes releasing coal, the rear chute is pulled in the order from the rear chute head to the tail of the machine.

[0014] In this embodiment, the rear slide is divided into a first section, a second section and a third section along its length direction, and the first section, the second section and the third section are respectively connected with an upper pull hydraulic cylinder, a lower pull hydraulic cylinder and a horizontal pull hydraulic cylinder. When the coal mining working face is advanced, the first section is pulled upward obliquely by the upper pull hydraulic cylinder, the second section is pulled downward obliquely by the lower pull hydraulic cylinder, and the third section is pulled horizontally by the horizontal pull hydraulic cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a flow chart of a mining method for a fully mechanized mining face containing interbedded gangue layers according to an embodiment of the present invention.

[0016] Figure 2 Schematic diagram of a second drilling arrangement according to an embodiment of the present invention.

[0017] Figure 3 It is a schematic diagram of the arrangement of the third drilling hole in an embodiment of the present invention.

[0018] Reference numerals:

[0019] 1. Tunnel; 2. Coal seam; 21. Gangue; 3. Second borehole; 4. Third borehole. DETAILED DESCRIPTION

[0020] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0021] like Figures 1 to 3 As shown in the figure, the X direction is the first direction, and the Y direction is the second direction. The mining method of the fully mechanized mining face containing intercalated gangue layer in this embodiment includes:

[0022] S100, constructing at least two tunnels 1 in the coal seam 2 along a first direction at intervals.

[0023] S200, constructing a first borehole along a second direction in a coal seam 2 between two adjacent tunnels 1, wherein the first borehole is connected to the tunnel 1, and the first direction is orthogonal to the second direction.

[0024] S300, injecting fracturing fluid into the first borehole.

[0025] For example, the fracturing fluid can be water, which is low in cost and easy to obtain, which is conducive to reducing costs. Of course, the fracturing fluid can also be selected in other forms, which are not limited here. The first borehole can be a deep hole blasting hole or a large diameter borehole, and a DN20 welded pipe is used to inject water into the second borehole 3 through a BZW40 / 60 high-pressure pump dynamic pressure water injection method.

[0026] Specifically, after the fracturing fluid is injected into the first borehole, the first borehole needs to be sealed to prevent the fracturing fluid from flowing out.

[0027] S400, constructing a second borehole 3 along a second direction in the coal seam 2 between two adjacent tunnels 1, the second borehole 3 being connected to the tunnel 1, and using the second borehole 3 for blasting.

[0028] S500 , constructing a third borehole 4 along a first direction on the gangue 21 of the coal mining face in the coal seam 2 between two adjacent tunnels 1 , and performing blasting using the third borehole 4 .

[0029] S600, mining the coal seam 2.

[0030] It can be understood that by constructing the second borehole 3 and injecting fracturing fluid into the coal seam 2, the fracturing fluid enters the tiny cracks and pores of the gangue 21, which can reduce the hardness of the gangue 21 in the coal seam 2 and make the gangue 21 easier to break. Then, a second borehole 3 is constructed in the coal seam 2, and blasting is performed using the second borehole 3 to break the gangue 21 into smaller fragments. In the coal mining face, a third borehole 4 is constructed on the gangue 21, and targeted blasting is performed on the gangue 21, which can further improve the crushing effect of the gangue 21 and reduce the working resistance of the coal mining machine, which is beneficial to improving the mining efficiency during coal mining, thereby reducing safety hazards. In addition, injecting fracturing fluid into the coal seam 2 before blasting can increase the area of ​​broken gangue 21, reduce the amount of explosives used, and reduce the dust generated during blasting.

[0031] In this embodiment, after the fracturing fluid is injected into the first borehole for a preset time, the second borehole 3 is used for blasting.

[0032] It is understandable that after the fracturing fluid is injected into the first borehole for a preset time, the fracturing fluid can better enter the cracks and pores of the coal body and the gangue 21, which is beneficial to improve the weakening effect on the gangue 21 and better reduce the hardness coefficient of the gangue 21.

[0033] In this embodiment, the preset time is 7 days to 10 days.

[0034] For example, the preset time can be 7 days, 8 days, 9 days or 10 days. If the preset time is too short, the fracturing fluid cannot fully enter the cracks or pores of the gangue 21, which is not conducive to improving the weakening effect of the gangue 21. If the preset time is too long, it is not conducive to reducing dust during subsequent blasting.

[0035] It can be understood that, in this embodiment, by setting the preset time to 7 to 10 days, the hydraulic fracturing can fully enter the cracks or pores of the gangue 21 while achieving a good dust prevention effect.

[0036] In this embodiment, if Figure 2 As shown, the second borehole 3 is constructed in multiple cycles and blasting is performed using the second borehole 3 .

[0037] For example, the number of rounds of cyclic construction may be two rounds, three rounds, or four rounds, etc. The number of rounds of cyclic construction may be selected according to actual conditions and is not limited here.

[0038] If there are too many second boreholes 3 in one round of construction and blasting is performed using the second boreholes 3, the second boreholes 3 are densely arranged and the blasting range is wide, which may easily cause coal body collapse and affect the normal and smooth progress of coal mining. Using multiple rounds of blasting can reduce the intensity of each round of blasting, which is conducive to improving safety.

[0039] In this embodiment, a plurality of second boreholes 3 are constructed at intervals along the first direction in each round, and each second borehole 3 constructed in a subsequent round is located between two adjacent second boreholes 3 constructed previously.

[0040] For example, Figure 2 As shown, when constructing two rounds of second boreholes 3, the distance between two adjacent second boreholes 3 in the first round is 9.6m, the distance between two adjacent second boreholes 3 in the second round is also 9.6m, and the distance between the second boreholes 3 constructed in the first round and the adjacent second boreholes 3 constructed in the second round is 4.8m.

[0041] It is understandable that each second borehole 3 of the subsequent round of construction is located between two adjacent second boreholes 3 constructed previously, which can evenly blast the coal seam 2, thereby improving the crushing effect of the gangue 21 and making the gangue 21 more evenly crushed.

[0042] In this embodiment, if Figure 3 As shown, there are multiple third bore holes 4, and the multiple third bore holes 4 are evenly spaced and distributed.

[0043] It should be noted that the distance A between two adjacent third boreholes 4 may be twice the blasting loosening range radius R. The calculation formula of the blasting loosening range radius R is as follows:

[0044]

[0045] Where P is the detonation pressure of the explosive; u d is the initial damage factor of rock; S t is the initial cross-sectional area of ​​the rock mass, r b is the radius of the explosive roll; α is the stress attenuation index during the blasting process, which is determined by experiments or empirical formulas; r c is the radius of the blasting area; D is the explosion velocity of the explosive; ρ is the density of the explosive.

[0046] The number of the third bore holes 4 can be set by those skilled in the art according to the cross-sectional area of ​​the gangue 21 in the radial direction of the third bore holes 4 and is not limited here.

[0047] like Figure 3 As shown, the arrangement of the third borehole 4 can be arranged in a "three-flower" or "five-flower" manner by installing long and short holes. The arrangement of the third borehole 4 in a "three-flower" or "five-flower" manner is a conventional prior art and will not be described in detail here. The combination of long and short holes can achieve different levels of crushing in one blast, which can not only process the hard rock mass in the deep layer, but also take into account the loose part of the surface layer, and can improve the overall blasting effect.

[0048] It can be understood that by arranging a plurality of third bore holes 4 at even intervals in the gangue 21 , the gangue 21 can be evenly blasted through the third bore holes 4 , thereby improving the crushing effect of the gangue 21 .

[0049] In this embodiment, in the radial direction of the third borehole 4 , the cross-sectional boundary of the gangue 21 is spaced from the adjacent third borehole 4 by a preset distance B, where B>0.

[0050] For example, Figure 3 As shown, when the distance A between two adjacent third boreholes 4 is 0.6 m, the preset distance B may be 1.2 m. The preset distance B may be set according to actual site conditions, and the specific value of the preset distance is not limited here.

[0051] It should be noted that the third bore hole 4 is not set in the blank space with a preset distance between the cross-sectional boundary of the gangue 21 and the adjacent third bore hole 4, so that the third bore hole 4 is away from the boundary of the gangue 21, thereby reducing the safety hazards (such as coal body collapse, gas explosion, etc.) caused by blasting using the third bore hole 4.

[0052] In this embodiment, when the coal seam 2 is a steeply inclined coal seam, the coal mining face is adjusted to a pseudo-inclined state for mining by making the height of the return air tunnel higher than the transportation tunnel and the transportation tunnel ahead of the return air tunnel.

[0053] It should be noted that when coal seam 2 is a steeply inclined coal seam, it is easy to cause the scraper conveyor on the working face to slip, resulting in the inability to accurately overlap the scraper conveyor and the transfer machine, thereby affecting the normal production.

[0054] Specifically, when the coal mining working face is adjusted to a pseudo-inclined state, the pseudo-inclined angle β of the coal mining working face can generally be designed to be between 1 / 3 and 1 / 5 of the working face slope angle (true inclination). The specific calculation method of the pseudo-inclined angle β is as follows:

[0055] a. If there is no slip, the conveyor will rise by Csinβ. Where C is the excavation distance of the coal mining machine cutting one cut.

[0056] b. According to on-site measurements, when β=0, the conveyor slides down H with each advancement cycle.

[0057] c. If the transport plane is to prevent it from sliding down, Csinβ=H, then sinβ=H / C.

[0058] Let the pseudo-slant distance (i.e., the distance that the transport lane advances ahead of the return air lane) be X,

[0059] Then: X = Msinβ, where: M is the length of the working surface.

[0060] That is, it is most beneficial to control the scraper conveyor when the working face is adjusted to the length of the transport lane ahead of the return air lane Msinβ.

[0061] In this embodiment, after the coal mining machine on the coal mining face finishes cutting a piece of coal, the front chute is moved in the order from the front chute head to the tail of the machine.

[0062] It should be noted that the front chute refers to the scraper conveyor located in front of the coal mining machine. The front chute head is the connection point between the front chute and the transfer machine or other transportation equipment, and is responsible for transferring the coal on the front chute to the next transportation link. When pushing the front chute, the front chute is pushed from the front chute head to the tail, that is, the front chute is pushed forward from the lower end to the higher end. During the pushing process, the lower part can support the upper part, thereby reducing the downward movement of the front chute during the pushing process.

[0063] In this embodiment, after each coal discharge from the rear chute is completed, when the rear chute is pulled, the rear chute is pulled from the front of the rear chute to the rear of the rear chute.

[0064] Similarly, when pushing the rear slide, push it in the order from the nose of the rear slide to the tail of the aircraft, that is, push the rear slide forward from the lower end to the higher end. During the pushing process, the lower part can support the upper part, thereby reducing the downward movement of the rear slide during the pushing process.

[0065] In this embodiment, the rear slide is divided into the first section, the second section and the third section along its length direction. The first section, the second section and the third section are connected with the upper pulling hydraulic cylinder, the lower pulling hydraulic cylinder and the horizontal pulling hydraulic cylinder respectively. When the coal mining working face is advanced, the first section is pulled upward obliquely by the upper pulling hydraulic cylinder, the second section is pulled downward obliquely by the lower pulling hydraulic cylinder, and the third section is pulled horizontally by the horizontal pulling hydraulic cylinder.

[0066] Specifically, the heights of the first section, the second section, and the third section are sequentially reduced along the working surface. One end of the pull-up hydraulic cylinder is connected to the first section of the rear slide, and the other end is connected to the hydraulic support. The pull-up hydraulic cylinder is arranged obliquely upward in the excavation direction of the working surface, and can pull the rear slide obliquely upward when the hydraulic support is pushed. One end of the pull-down hydraulic cylinder is connected to the second section of the rear slide, and the other end is connected to the hydraulic support. The pull-down hydraulic cylinder is arranged obliquely downward in the excavation direction of the working surface, and can pull the rear slide obliquely downward when the hydraulic support is pushed. One end of the horizontal pull hydraulic cylinder is connected to the third section, and the other end is connected to the hydraulic support. The horizontal pull hydraulic cylinder is arranged horizontally in the excavation direction of the working surface, and can pull the rear slide horizontally through the horizontal pressure hydraulic cylinder when the hydraulic support is pushed.

[0067] It should be noted that during the movement of the working surface, due to the inclination of the working surface, the rear slide is easy to slide down due to its own gravity and is difficult to control. During the movement of the working surface, the first section is pulled by the upward pulling hydraulic cylinder, so that the rear slide can be pulled upward along the moving direction, and at the same time, the rear slide can be pulled downward along the moving direction by the downward pulling hydraulic cylinder, and the rear slide can be pulled horizontally along the moving direction by the horizontal pulling hydraulic cylinder, so that the inclined upward pulling force on the rear slide is balanced with the downward component of gravity along the working surface, thereby making the rear slide balanced in force during the movement.

[0068] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0069] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0070] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0071] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0072] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0073] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A mining method for a fully mechanized mining face containing interlayer gangue, characterized in that: The steps include: constructing at least two tunnels in the coal seam at intervals along a first direction; In the coal seam between two adjacent tunnels, constructing a first borehole along a second direction, the first borehole is connected to the tunnel, and the first direction is orthogonal to the second direction; injecting fracturing fluid into the first borehole; In the coal seam between two adjacent tunnels, construct a second borehole along the second direction, the second borehole is connected to the tunnel, and blasting is performed using the second borehole; constructing a third borehole along the first direction on the gangue of the coal mining face in the coal seam between the two adjacent tunnels, and using the third borehole for blasting; The coal seam is mined.

2. The mining method of fully mechanized mining face containing intercalated gangue layer according to claim 1 is characterized in that: After the fracturing fluid is injected into the first borehole for a preset time, the second borehole is used for blasting.

3. The mining method of fully mechanized mining face containing intercalated gangue layer according to claim 2 is characterized in that: The preset time is 7 to 10 days.

4. The mining method of fully mechanized mining face containing intercalated gangue layer according to claim 1, characterized in that: The second borehole is constructed in multiple cycles and blasting is performed using the second borehole.

5. The mining method of fully mechanized mining face containing intercalated gangue layer according to claim 4, characterized in that: A plurality of the second boreholes are constructed at intervals along the first direction each time, and each of the second boreholes constructed in a subsequent construction is located between two adjacent second boreholes constructed previously.

6. The mining method of fully mechanized mining face containing intercalated gangue layer according to claim 1, characterized in that: There are multiple third bore holes, and the multiple third bore holes are evenly spaced and distributed.

7. The mining method of fully mechanized mining face containing intercalated gangue layer according to claim 1, characterized in that: In the projection in the first direction, a boundary of the gangue is spaced a preset distance from the adjacent third borehole.

8. The mining method of fully mechanized mining face containing interlayer gangue according to claim 1, characterized in that: When the coal seam is a steeply inclined coal seam, the coal mining face is adjusted to a pseudo-inclined state for mining by making the height of the return air roadway higher than the transportation roadway and the transportation roadway ahead of the return air roadway.

9. The mining method of fully mechanized mining face containing intercalated gangue layer according to claim 8, characterized in that: After the coal mining machine on the coal mining face has finished cutting a piece of coal, the front chute is moved in the order from the front chute head to the tail of the machine; And / or, after each coal discharge from the rear chute is completed, when the rear chute is pulled, the rear chute is pulled from the front to the rear of the rear chute.

10. The mining method of fully mechanized mining face containing intercalated gangue layer according to claim 8, characterized in that: The rear slide is divided into a first section, a second section and a third section along its length direction, and the first section, the second section and the third section are respectively connected with an upper pull hydraulic cylinder, a lower pull hydraulic cylinder and a horizontal pull hydraulic cylinder. When the coal mining face is advanced, the first section is pulled upward obliquely by the upper pull hydraulic cylinder, the second section is pulled downward obliquely by the lower pull hydraulic cylinder, and the third section is pulled horizontally by the horizontal pull hydraulic cylinder.

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