The method of breaking top blasting behind the working face

Abstract

The present invention provides a method for blasting the broken top after the working face frame, and relates to the technical field of blasting the roof of the goaf. The method for blasting the broken top after the working face frame includes: when the working face starts to be mined, when the phenomenon of the suspended top after the working face frame appears, the blasting distance of the working face inclination, the blasting distance of the working face strike, the blasting depth and the angle of the blasting hole are determined, and a blasting hole is drilled at the front end of the hydraulic support and on the side of the flume close to the working face; the blasting hole is divided into a mud sealing section and a charge charging section, and mud sealing operations and charge charging operations are performed respectively; based on the strength of the roof, the blasting type is selected and the blasting is implemented. The method can blast the suspended top after the frame is dropped, without the need to additionally strengthen the support of the working face and the flume, the cost is low, and the pressure relief effect is good; the method has little impact on normal production, and can effectively avoid excessive blasting and redundant blasting, the blasting range is small, and the damage is small; the method drills the blasting hole at the front end of the hydraulic support, which is safer than drilling the blasting hole in the goaf.

Description

Technical Field

[0001] The invention relates to the technical field of goaf roof blasting, and in particular to a method for roof blasting after a working face frame is erected. Background Art

[0002] During coal mining, under conditions such as hard roof, composite roof, thin and medium-thick coal seams, the roof of the goaf often fails to collapse smoothly. Since the roof of the goaf lags behind the working face, the working space is small, the roof is unstable, and the gas content is high, the falling of the roof is extremely difficult and dangerous. The roof includes the direct roof layer above the coal seam and the first basic roof layer above the direct roof layer.

[0003] In the prior art, in order to solve the above problems, the working face and the drift support are usually strengthened, and the roof of the goaf is waited for to fall randomly. However, the economic cost of this method is high, and the strengthening effect is usually poor. Summary of the invention

[0004] The purpose of the present invention is to provide a method for blasting the roof after the working face frame, so as to solve the technical problems in the prior art that the roof of the goaf cannot be smoothly collapsed by strengthening the support, which has high economic cost and poor effect.

[0005] The method for blasting the working face after the roof breaking provided by the present invention comprises the following steps:

[0006] S100 The working face starts to be mined. When the hanging roof phenomenon appears behind the working face frame, the working face inclination blasting distance, the working face strike blasting distance, the blasting depth and the angle of the blasting hole are determined, and a blasting hole is drilled at the front end of the hydraulic support and on the side of the slot close to the working face; wherein the working face inclination blasting distance is the blasting distance in the horizontal direction perpendicular to the working face strike, and the blasting depth is the blasting distance in the vertical direction perpendicular to the working face strike;

[0007] S200 divides the blasting hole into a mud sealing section and a charge charging section, and performs mud sealing operations and charge charging operations respectively;

[0008] S300 selects the blasting type based on the strength of the roof and implements the blasting.

[0009] Furthermore, the working face inclination blasting distance is 1 / 2 of the working face periodic pressure step distance.

[0010] Furthermore, the blasting distance along the working face is twice the supporting length of the hydraulic support.

[0011] Furthermore, the blasting depth is greater than or equal to the sum of the heights of the direct top layer and the first basic top layer.

[0012] Preferably, in this embodiment, the blasting depth is equal to the sum of the heights of the direct top layer and the first basic top layer. Setting the blasting depth in this way can not only blast and drop the first basic top layer, but also effectively avoid over-blasting, and the blasting cost is low.

[0013] Furthermore, the length of the projection of the sealing section in the horizontal plane is equal to the supporting length of the hydraulic support along the working surface, and the charging section is located above the sealing section.

[0014] Under this setting mode, sufficient mud sealing sections are left in the blasting holes, thereby effectively protecting the integrity of the top plate above the hydraulic support, and thus effectively avoiding the roof collapse phenomenon on the working face.

[0015] Furthermore, the blasting hole comprises a first blasting hole and a second blasting hole, and when drilling the blasting hole, the bottom ends of the first blasting hole and the second blasting hole are overlapped.

[0016] Further, in a plane perpendicular to the direction of the working face, the projection of the first blasting hole extends in a vertical direction.

[0017] Furthermore, the blasting holes also include a third blasting hole. When drilling the blasting holes, the bottom ends of the three blasting holes overlap, the three blasting holes are located in the same plane, and the third blasting hole is located between the first blasting hole and the second blasting hole.

[0018] Preferably, in a plane perpendicular to the direction of the working face, the angle between the projection of the third blasting hole and the projection of the first blasting hole, and the angle between the projection of the third blasting hole and the projection of the second blasting hole are equal. With such an arrangement, the first blasting hole, the third blasting hole and the second blasting hole are distributed more evenly, which is conducive to improving the blasting effect.

[0019] Furthermore, the first blasting hole implements single-side blasting, and the blasting direction is the direction away from the drift.

[0020] Furthermore, in step S400, when the stiffness coefficient f of the roof is ≤4, concentrated-energy blasting is selected and implemented; when the stiffness coefficient f of the roof is >4, non-concentrated-energy blasting is selected and implemented.

[0021] Under this setting, different types of blasting are carried out for roofs with different hardness coefficients. When the hardness coefficient of the roof is low, concentrated blasting is used, which is conducive to ensuring the safety of the working face support; when the hardness coefficient of the roof is high, non-concentrated blasting is used, which has a good effect on the cracking of the roof. It not only adapts to different roof conditions and ensures the roof is broken, but also can effectively avoid excessive damage to the integrity of the roof.

[0022] The working face rear roof breaking blasting method provided by the present invention can produce the following beneficial effects:

[0023] The method for blasting the broken roof behind the working face frame provided by the present invention can blast the suspended roof after the frame is lowered, without the need to additionally strengthen the support of the working face and the drift, with low cost and good pressure relief effect; furthermore, the method is implemented after the working face is normally mined and the suspended roof phenomenon occurs behind the hydraulic support, without the need for additional operations before mining, with little impact on normal production, and compared with the advance blasting before mining and the blasting before the suspended roof phenomenon occurs, it can effectively avoid excessive blasting and redundant blasting, with a small blasting range and little damage; in addition, the method drills blasting holes at the front end of the hydraulic support, which is safer than drilling blasting holes in the goaf. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0025] Figure 1 A flow chart of the method for blasting the top of a working face frame provided by the present invention;

[0026] Figure 2 A schematic diagram of a blasting hole in a plane perpendicular to the direction of the working face in the method for blasting the top of a working face frame provided by the present invention;

[0027] Figure 3 for Figure 2 Center AA view.

[0028] Description of reference numerals:

[0029] 100-coal seam; 200-slot; 300-direct top layer; 400-first layer basic top layer; 500-hydraulic support; 600-goaf; 700-waste rock;

[0030] 910-first blasting hole; 920-second blasting hole; 930-third blasting hole; 901-sealing mud section; 902-charging section. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] It should be noted that, in the present application, the “roof” includes the direct roof layer 300 above the coal seam 100 and the first basic roof layer 400 above the direct roof layer 300, and the “hanging roof phenomenon behind the working face” refers to: along the direction of the working face, behind the hydraulic support 500, the direct roof layer 300 and the rock layers above are suspended, or the first basic roof layer 400 and the rock layers above are suspended.

[0033] Figure 1 This is a flow chart of the working face rear roof breaking blasting method provided in this embodiment.

[0034] This embodiment provides a method for blasting the top of a working face frame. Figure 1 As shown, the working face rear roof breaking blasting method comprises the following steps:

[0035] S100 The working face starts to be mined. When the hanging roof phenomenon appears behind the working face frame, the working face inclination blasting distance a, the working face strike blasting distance b, the blasting depth c and the angle of the blasting hole are determined, and a blasting hole is drilled at the front end of the hydraulic support 500 and on the side of the chute 200 close to the working face; wherein, the working face inclination blasting distance is the blasting distance in the horizontal direction perpendicular to the working face strike, and the blasting depth is the blasting distance in the vertical direction perpendicular to the working face strike;

[0036] S200 divides the blasting hole into a mud sealing section 901 and a charge charging section 902, and performs mud sealing operations and charge charging operations respectively;

[0037] S300 selects the blasting type based on the strength of the roof and implements the blasting.

[0038] The method for blasting the broken top behind the working face frame provided in this embodiment can blast the suspended top behind the frame without additionally strengthening the support of the working face and the drift 200, with low cost and good pressure relief effect; furthermore, the method is implemented after the working face is normally mined and the suspended top phenomenon appears behind the hydraulic support 500, without the need for additional operations before mining, with little impact on normal production, and compared with the advance blasting before mining and the blasting before the suspended top phenomenon appears, it can effectively avoid excessive blasting and unnecessary blasting, with a small blasting range and little damage; in addition, the method drills blasting holes at the front end of the hydraulic support 500, which is safer than drilling blasting holes in the goaf 600.

[0039] Specifically, in this embodiment, the hanging roof phenomenon can be discovered through manual observation or instrument detection. After the hanging roof phenomenon occurs, it will be accompanied by various manifestations, so the appearance of the hanging roof behind the frame can be observed manually from the working face and the chute 200; in addition, the appearance of the hanging roof will also cause the pressure of the hydraulic support 500 on the working face to increase, so it can also be observed through the pressure monitoring gauge of the hydraulic support 500.

[0040] Figure 2 It is a schematic diagram of the blasting hole in the plane perpendicular to the direction of the working face in the working face rear roof breaking blasting method provided in this embodiment.

[0041] Specifically, in this embodiment, Figure 2 As shown, the working face inclined blasting distance a is 1 / 2 of the working face periodic pressure step distance. With this arrangement, the first layer basic top layer 400 is more prone to lateral fracture, and lateral cutting can be achieved better. The periodic pressure step distance of the coal mining working face is usually 10-40m, so the working face inclined blasting distance a is 5-20m.

[0042] Figure 3 for Figure 2 The AA view in the middle is a schematic diagram of the blasting hole in a plane parallel to the working face.

[0043] Specifically, in this embodiment, Figure 3 As shown, the blasting distance b of the working face is twice the support length of the hydraulic support 500. The support length of the hydraulic support 500 is usually about 4m, that is, the blasting distance of the working face is about 8m. In this way, the blasting distance after the support is equal to the support length of the hydraulic support 500, which is conducive to ensuring the fracture and collapse of the suspended roof under gravity conditions.

[0044] It should be noted that the "support length of the hydraulic support 500" refers to: the distance between the front and rear ends of the hydraulic support 500 that are in contact with the direct top layer 300 along the direction of the working surface.

[0045] Specifically, in this embodiment, Figure 2 As shown, the blasting depth c is greater than or equal to the sum of the heights of the direct top layer 300 and the first basic top layer 400 .

[0046] Preferably, in this embodiment, the blasting depth c is equal to the sum of the heights of the direct top layer 300 and the first basic top layer 400. Setting the blasting depth c for blasting in this way can not only blast and drop the first basic top layer 400, but also effectively avoid over-blasting, and the blasting cost is low.

[0047] Specifically, in this embodiment, Figure 3 As shown, the length of the projection of the sealing section 901 in the horizontal plane is equal to the support length of the hydraulic support 500 along the working face, and the charging section 902 is located above the sealing section 901. In this way, the blasting hole has enough sealing sections 901, which can effectively protect the integrity of the top plate above the hydraulic support 500, and thus effectively avoid the roof collapse phenomenon of the working face.

[0048] Specifically, in this embodiment, Figure 2As shown, the blasting holes include a first blasting hole 910 and a second blasting hole 920. When drilling the blasting holes, the bottom ends of the first blasting hole 910 and the second blasting hole 920 are overlapped.

[0049] Specifically, in this embodiment, in a plane perpendicular to the direction of the working face, the projection of the first blasting hole 910 extends in the vertical direction.

[0050] Specifically, in this embodiment, continue as Figure 2 As shown, the blasting holes also include a third blasting hole 930 . When drilling the blasting holes, the bottom ends of the three blasting holes overlap, the three blasting holes are located in the same plane, and the third blasting hole 930 is located between the first blasting hole 910 and the second blasting hole 920 .

[0051] Preferably, in a plane perpendicular to the direction of the working face, the angle between the projection of the third blasting hole 930 and the projection of the first blasting hole 910 is equal to the angle between the projection of the third blasting hole 930 and the projection of the second blasting hole 920. With such an arrangement, the first blasting hole 910, the third blasting hole 930 and the second blasting hole 920 are distributed more evenly, which is conducive to improving the blasting effect.

[0052] It should be noted that, in other embodiments of the present application, the number of blasting holes is not limited to three. For example, the number of blasting holes can also be two or four, etc., which can be specifically set according to the width of the working surface, etc.

[0053] It should also be noted that, in other embodiments of the present application, the third blasting hole 930 may not be located in the plane where the first blasting hole 910 and the second blasting hole 920 are located.

[0054] Specifically, in this embodiment, Figure 2 As shown, the arrows around the blasting holes indicate the blasting directions thereof, wherein the first blasting hole 910 implements single-side blasting, and the blasting direction is the direction away from the drift 200 .

[0055] Specifically, in this embodiment, in step S400, when the hardness coefficient of the roof f≤4, concentrated blasting is selected and implemented; when the hardness coefficient of the roof f>4, non-concentrated blasting is selected and implemented. Different types of blasting are implemented for roofs with different hardness coefficients. Concentrated blasting is used when the hardness coefficient of the roof is low, which is conducive to ensuring the safety of the working face support; and non-concentrated blasting is used when the hardness coefficient of the roof is high, which has a good cracking effect on the roof. It not only adapts to different roof conditions and ensures the broken roof, but also can effectively avoid excessive damage to the integrity of the roof.

[0056] Finally, it should be noted that, in this article, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0057] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to the embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of blasting the top of a working face after the frame is broken. It is characterized in that The following steps are involved: S100 The working face starts to be mined. When the hanging roof phenomenon appears behind the working face frame, the working face inclination blasting distance, the working face strike blasting distance, the blasting depth and the angle of the blasting hole are determined, and a blasting hole is drilled at the front end of the hydraulic support (500) and on the side of the chute (200) close to the working face; wherein the working face inclination blasting distance is the blasting distance in the horizontal direction perpendicular to the working face strike, and the blasting depth is the blasting distance in the vertical direction perpendicular to the working face strike; The working face inclination blasting distance is 1 / 2 of the working face periodic pressure step distance; the working face strike blasting distance is twice the support length of the hydraulic support (500); the blasting depth is greater than or equal to the sum of the heights of the direct top layer (300) and the first basic top layer (400); The blasting holes include a first blasting hole (910), a second blasting hole (920) and a third blasting hole (930). When drilling the blasting holes, the bottom ends of the three blasting holes overlap, the three blasting holes are located in the same plane, and the third blasting hole (930) is located between the first blasting hole (910) and the second blasting hole (920); in a plane perpendicular to the direction of the working face, the projection of the first blasting hole (910) extends in the vertical direction; in a plane perpendicular to the inclination of the working face, the projections of the three blasting holes all extend obliquely backward; S200 divides the blasting hole into a mud sealing section (901) and a charge charging section (902), and performs mud sealing operations and charge charging operations respectively; S300 selects the blasting type and implements the blasting based on the strength of the roof: when the stiffness coefficient f of the roof is less than or equal to 4, selects and implements the concentrated blasting; when the stiffness coefficient f of the roof is greater than 4, selects and implements the non-concentrated blasting.

2. The method for blasting the working face after breaking the top according to claim 1, It is characterized in that The length of the projection of the mud sealing section (901) in the horizontal plane is equal to the supporting length of the hydraulic support (500) along the working surface, and the charging section (902) is located above the mud sealing section (901).

3. The method for blasting the working face after breaking the top according to claim 2, It is characterized in that The first blasting hole (910) is subjected to single-side blasting, and the blasting direction is a direction away from the drift (200).

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