Deep hole blasting weakening method for ultra-thin fully mechanized coal mining face to pass through special-shaped hard fault

Abstract

The invention belongs to the technical field of coal mining, and particularly relates to a deep hole blasting weakening method for an ultra-thin fully mechanized coal mining face to pass through a special-shaped hard fault, which comprises the following steps of: 1, detecting the distribution condition of the fault; secondly, drilling holes are designed according to the fault distribution condition, and blast holes are drilled in the working face; thirdly, explosive is loaded into the blast hole, and the blast hole is sealed; step 4, detonating; in the first step, when fault distribution conditions are detected, the trend and the distribution range of faults are preliminarily analyzed according to section conditions exposed by an upper gate way and a lower gate way and mining area geological data, a directional drilling machine is used for drilling a plurality of detection holes along the boundary range of the faults, and the distribution conditions of the faults are tested; a directional drilling machine is used for drilling holes in the working face in the direction parallel to the stope working face, and the fault distribution condition in the working face is further determined. According to the method, smooth mining of the working face is guaranteed, the mining efficiency is improved, and meanwhile high safety is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mining, and particularly relates to a deep-hole blasting weakening method for an extremely thin fully-mechanized mining face passing through a deformed hard fault. Background Art

[0002] During the mining process of thin coal seams, they are easily affected by faults, and even a slight fault will cause coal seam loss.

[0003] As a common geological structure in the coal mining process, faults, due to factors such as their structural characteristics and mechanical properties, severely restrict the high-yield and high-efficiency of the working face, especially large-drop faults. Faults are often encountered in coal mining. Some faults can be avoided during the design of the working face, but some often cannot be avoided in the layout of the fully-mechanized mining face. If the shearer is forced to push through, due to the hardness of the rock being greater than that of the coal body, the rock-breaking efficiency is low and the pick consumption is large.

[0004] Therefore, a deep-hole blasting weakening method for an extremely thin fully-mechanized mining face passing through a deformed hard fault is proposed. Summary of the Invention

[0005] The purpose of the invention is to provide a deep-hole blasting weakening method for an extremely thin fully-mechanized mining face passing through a deformed hard fault to solve the above problems.

[0006] To achieve the above purpose, the invention provides the following scheme:

[0007] A deep-hole blasting weakening method for an extremely thin fully-mechanized mining face passing through a deformed hard fault includes the following steps:

[0008] Step 1, detecting the distribution of the fault;

[0009] Step 2, designing drill holes according to the distribution of the fault and drilling blast holes on the working face;

[0010] Step 3, loading explosives into the blast holes and sealing the blast holes;

[0011] Step 4, initiating the explosion;

[0012] In Step 1, when detecting the distribution of the fault, first, based on the exposed section conditions of the upper and lower gate roads and the geological data of the mining area, preliminarily analyze the strike and distribution range of the fault. Use a directional drilling rig to drill multiple detection holes along the boundary range of the fault to test the distribution of the fault. Use a directional drilling rig to drill holes on the working face along the direction parallel to the mining face to further determine the distribution of the fault within the working face.

[0013] Preferably, in step two, before designing the drill holes, first determine the blasting fragmentation range and blasting height, and select the drill hole opening angle, the number of drill holes, and the drill hole arrangement method according to the blasting fragmentation range, the blasting height, and the radius of the blasting fracture circle of the explosive.

[0014] Preferably, the calculation formula for the radius of the blasting fracture circle of the explosive is:

[0015]

[0016] Among them, R p is the radius of the blasting fracture circle of the explosive, P is the peak value of the initial radial stress of the stress wave, r b is the radius of the blast hole, S t is the tensile strength of the rock mass, v is the Poisson's ratio, and α is the stress wave attenuation value.

[0017] Preferably, the calculation formula for the stress wave attenuation value is:

[0018] α = 2 - v / (1 - v).

[0019] Preferably, in step three, the explosive includes a cartridge and a detonator head. When filling, first use a hole-probing tube to detect the length of the blast hole, determine the filling length of the explosive according to the length of the blast hole, and then sequentially fill the cartridge into the blast hole through the hole-probing tube. After the cartridge filling is completed, fill the detonator head.

[0020] Preferably, anti-slip threads are provided on the cartridge.

[0021] Preferably, the method for manufacturing the detonator head is as follows: select a cartridge, remove the end cap of the cartridge, drill two small holes in the end cap, pass gelatine wires through the holes and tie them, connect the two gelatine wires to two detonators respectively, and fix the end cap to the cartridge to complete the production.

[0022] Preferably, in step three, when sealing the blast hole, use grouting to seal the hole. Insert the grouting pipe and the return slurry pipe into the blast hole, and block the blast hole opening with a plug. Both the grouting pipe and the return slurry pipe penetrate through the plug. One end of the grouting pipe in the blast hole is close to the blast hole opening, the other end of the grouting pipe is connected to a grouting pump, one end of the return slurry pipe in the blast hole is connected to a return slurry pipe head, the return slurry pipe head is fixed to the detonator head, and the other end of the return slurry pipe extends out of the plug.

[0023] Preferably, before manufacturing the detonator head, check the resistance of the detonator, and the resistance error of the detonator does not exceed 0.2 Ω.

[0024] Preferably, a gate valve is provided at the slurry outlet of the grouting pump. The outlet end of the gate valve is fixedly connected and communicated with a first quick connector. One end of the grouting pipe extending out of the blast hole is fixedly connected and communicated with a second quick connector. The first quick connector and the second quick connector are adapted and detachably connected.

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

[0026] The present invention provides a deep-hole blasting weakening method for an extremely thin fully-mechanized coal mining face passing through a deformed hard fault. Before mining, the fault is pre-cracked by blasting. The pre-cracked fault rock is co-mined with the coal mine, without the need to avoid the fault, and without the need for a shearer to forcibly push through, ensuring the smooth extraction of the working face, improving the extraction efficiency, and having high safety at the same time.

[0027] The distribution of the fault is detected by means of directional drilling, which reduces the detection cost, and the detection result is more accurate and not easily affected by environmental factors. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings:

[0029] Figure 1 It is a diagram of the fault distribution detected in the present invention;

[0030] Figure 2 It is a partial blast hole distribution diagram of the lower gate roadway in the present invention;

[0031] Figure 3 It is an effect diagram of fragmentation in the present invention; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0033] To make the above objects, features, and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0034] The present invention discloses a deep-hole blasting weakening method for an extremely thin fully-mechanized coal mining face passing through a deformed hard fault, including the following steps:

[0035] Step 1: Detect the distribution of the fault;

[0036] Step 2: Design the drill holes according to the distribution of the fault and drill blast holes on the working face;

[0037] Step 3: Load explosives into the blast holes and seal the blast holes;

[0038] Step 4: Initiation

[0039] In Step 1, when detecting the distribution of faults, first, based on the cross-sectional conditions exposed in the upper and lower headings and the mining area geological data, preliminarily analyze the strike and distribution range of the faults. Use a directional drilling rig to drill multiple detection holes along the boundary range of the faults to test the distribution of the faults. Use the directional drilling rig to drill holes on the working face along the direction parallel to the coal mining face to further determine the distribution of faults within the working face.

[0040] For further optimized solutions, in Step 2, before designing the boreholes, first determine the blasting fragmentation range and blasting height, and select the borehole opening angle, the number of boreholes, and the borehole arrangement method according to the blasting fragmentation range, blasting height, and the radius of the blasting fracture circle of the explosive.

[0041] For further optimized solutions, the calculation formula for the radius of the blasting fracture circle of the explosive is:

[0042]

[0043] where R p is the radius of the blasting fracture circle of the explosive, P is the peak value of the initial radial stress of the stress wave, r b is the radius of the blast hole, S t is the tensile strength of the rock mass, v is the Poisson's ratio, and α is the stress wave attenuation value.

[0044] For further optimized solutions, the calculation formula for the stress wave attenuation value is:

[0045] α = 2 - v / (1 - v).

[0046] For further optimized solutions, in Step 3, the explosive includes a cartridge and a primer. When filling, first use a probe tube to detect the length of the blast hole, determine the filling length of the explosive according to the length of the blast hole, then sequentially fill the cartridge into the blast hole through the probe tube, and fill the primer after the cartridge filling is completed.

[0047] For further optimized solutions, anti-slip threads are provided on the cartridge.

[0048] For further optimized solutions, the manufacturing method of the primer is: select a cartridge, remove the end cap of the cartridge, drill two small holes in the end cap, pass gelatinous wires through the holes and tie them, connect the two gelatinous wires to two detonators respectively, and fix the end cap to the cartridge to complete the production.

[0049] For the further optimized solution, in step three, when sealing the blast holes, grouting is used for hole sealing. The grouting pipe and the slurry return pipe are inserted into the blast holes, and the blast hole openings are blocked by plugs. Both the grouting pipe and the slurry return pipe penetrate through the plugs. The end of the grouting pipe inside the blast hole is close to the blast hole opening, the other end of the grouting pipe is connected to a grouting pump, the end of the slurry return pipe inside the blast hole is connected to a slurry return pipe head, the slurry return pipe head is fixed to the blast head, and the other end of the slurry return pipe extends out of the plug.

[0050] For the further optimized solution, before manufacturing the blast head, the detonators are checked for resistance, and the resistance error of the detonators does not exceed 0.2 Ω.

[0051] For the further optimized solution, a gate valve is provided at the slurry outlet of the grouting pump. The outlet end of the gate valve is fixedly connected and communicated with a first quick connector. The end of the grouting pipe extending out of the blast hole is fixedly connected and communicated with a second quick connector. The first quick connector and the second quick connector are adapted and detachably connected.

[0052] One specific example:

[0053] Coal seam overview: The coal seam in the 2618 working face is relatively stable, the coal seam structure is simple, and there is no parting. The workability index (Km) is 1, and the coal thickness variation coefficient (γ) is 7.8%. The coal seam thickness is 0.7 - 1.09 m, and the average coal seam thickness is 0.9 m. The strike of the coal seam is 143 - 125 degrees from west to east, and the dip is 53 - 35 degrees. The average dip angle of the coal seam is 17 degrees.

[0054] Coal seam roof and floor conditions:

[0055]

[0056]

[0057] Fault situation:

[0058]

[0059] Mining area design and general situation of mining area roadway layout:

[0060] The 2618 working face is located in the second mining area at the -800 m level in the southern part of the minefield. It is adjacent to the six-layer track rise in the east, the F2 fault in the west, the six-layer gathering haulage roadway in the south, and the F10 fault in the north. The mining range of the working face is: east to the designed stop line, west to the cutting eye, south to the upper gate roadway, and north to the lower gate roadway. The overlying 2nd, 3rd, and 4th coal seams have been mined, the underlying 11th coal seam has been mined, and the 13th and 15th coal seams have not been mined.

[0061] Upper gate roadway of the coal mining working face:

[0062] The roadway on the south side of the 2618 working face is the upper gate roadway, which is arranged along the coal seam and is mainly used for the return air and material transportation of this working face. The roadway has an arched roof section, is supported by anchor nets and straps, with a net width of 4.2 m, a net height of 2.6 m, and a cross-sectional area of 10.92 m2 .

[0063] There is a 108mm dust-proof pipeline, a 108mm high-pressure air pipeline, a 32mm high-pressure rubber hose for liquid inlet, and a 51mm return liquid pipeline in the upper crossheading.

[0064] Lower crossheading of coal mining face:

[0065] The roadway on the north side of the 2618 working face is the lower crossheading, which is arranged along the coal seam. The loader and belt conveyor are installed along the upper side of the roadway, mainly used for the intake air and coal transportation of this working face. The roadway has an arched roof section, supported by anchor nets and belts, with a net width of 4.2m, a net height of 2.6m, and a cross-sectional area of 10.92m 2 .

[0066] There is a 108mm dust-proof pipeline, a 108mm high-pressure air pipeline, and a 108mm drainage pipeline in the lower crossheading.

[0067] Cutting roadway of the working face:

[0068] The cutting roadway of the 2618 working face is 135.2m, and the cutting roadway is arranged along the coal seam. The roadway adopts a rectangular section, with a net width of 5.6m, a net height of 2.1m, and a cross-sectional area of 11.96m 2 . It is mainly used for the intake air, pedestrian passage, material transportation and installation of this working face.

[0069] Blasting method:

[0070] Detect the distribution of faults: First, preliminarily analyze the strike and distribution range of faults based on the exposed section conditions of the upper crossheading and the lower crossheading and the geological data of the mining area. Use a directional drill combined with the function of measuring while drilling to drill multiple detection holes along the boundary range of the fault to test the distribution of the fault. Use a directional drill to drill holes on the working face along the direction parallel to the coal mining face, with a hole spacing of 10m, to further determine the distribution of faults within the working face. Refer to Figure 1 , where ABCD are detection holes and the red positions are faults;

[0071] Calculate the radius of the blasting fracture circle, and select the opening angle, number and arrangement method of blast holes according to the radius of the blasting fracture circle, the blasting fragmentation range and the blasting height.

[0072] The blasting fragmentation range is 30m in front of the fault horizontally and 4m behind the fault, and the blasting height is within 5m of the fault throw; the direction of the blast holes is parallel to the working face, without considering the horizontal angle; the hole spacing of the blast holes is 1.2m, and two rows of blast holes are arranged in the roadway, and the two rows of blast holes are staggered;

[0073] The explosive column selects a plastic-coated type III coal mine permitted water gel explosive, and the length of each coated explosive column is 1m and the weight is 3.3kg;

[0074] To avoid the pipe effect, detonating cords with a length of 0.3 m are inserted at both ends of the explosive column. The detonation velocity of the detonating cord is greater than the wave velocity of the air shock wave, ensuring stable detonation transmission of the explosive column in the blast hole;

[0075] 2 - 5 anti - slip wires with a length of about 350 mm are inserted into the front end of the explosive column. The anti - slip wires enter the blast hole to form barbs, thus preventing the blast hole from slipping.

[0076] The detonator uses a coal - mine permitted 1 - 5 - segment millisecond - delay electric detonator;

[0077] During drilling, to prevent hole collapse, after the blast hole is opened, a hole - probing pipe is immediately used to probe the hole. The length of the explosive charge is determined according to the length of the blast hole, and then the explosive column is sequentially filled into the blast hole through the hole - probing pipe. After the explosive column is filled, the blast head is filled.

[0078] Method for making the blast head: Select an explosive column, remove the end cap of the explosive column, drill two small holes near the inner wall edge of the end cap. The diameter of the small holes is about 6 mm. Insert two gummed wires for blasting into the two small holes of the end cap respectively, tie a knot, and waterproof - connect the two gummed wires to an electric detonator with a leg wire length of 15 cm - 20 cm respectively using self - adhesive tape to make the blast head. Bond the end cap and the explosive column with tape to complete the fixation. Wrap the wires of the detonator with tape to prevent the wire skin from being cracked during the process of pushing the explosive.

[0079] When sealing the blast hole, grouting is used for sealing. The grouting pipe and the slurry - return pipe are inserted into the blast hole, and the blast - hole opening is blocked by a plug. Both the grouting pipe and the slurry - return pipe penetrate the plug. The end of the grouting pipe inside the blast hole is close to the blast - hole opening. The other end of the grouting pipe is connected to a grouting pump. The end of the slurry - return pipe inside the blast hole is connected to a slurry - return pipe head, and the slurry - return pipe head is fixed to the blast head. The other end of the slurry - return pipe extends out of the plug.

[0080] A gate valve is arranged at the slurry outlet of the grouting pump. The outlet end of the gate valve is fixedly connected and communicated with a first quick - coupling. The end of the grouting pipe extending out of the blast hole is fixedly connected and communicated with a second quick - coupling. The first quick - coupling and the second quick - coupling are adapted and detachably connected, facilitating rapid grouting.

[0081] During grouting, to prevent different ratios of the sealing agent and water, each time a bag of 425 or 525 cement is poured into the grouting machine, 70% water is added, accurately measured with a quantitative plastic bucket, manually mixed evenly and then grouted. Repeat multiple times until the grouting is completed.

[0082] When there is slurry flowing out of the slurry - return pipe, block the slurry - return pipe, stop grouting, and after the grouting is completed, wait for at least 24 h for blasting. During blasting, all the detonator series - connection networks outside the blast holes are detonated. And set up a warning in accordance with the relevant mine safety technical measures. And when the gas drainage system is intact, all gas meters are intact, all warnings are in place, and power cut and personnel evacuation are in place, notify the dispatcher for permission before detonating.

[0083] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0084] The embodiments described above are only for describing the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the spirit of the design of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A deep-hole blasting weakening method for an extremely thin fully-mechanized mining face to pass through a special-shaped hard fault, characterized in that, It includes the following steps: Step 1: Detect the distribution of faults; Step 2: Design boreholes according to the fault distribution and drill blast holes on the working face; Step 3: Load explosives into the blast holes and seal the blast holes; Step 4: Initiate detonation; In Step 1, when detecting the fault distribution, first, based on the exposed section conditions of the upper and lower headings and the mining area geological data, preliminarily analyze the strike and distribution range of the faults. Use a directional drill to drill multiple detection holes along the boundary range of the faults to test the fault distribution. Use the directional drill to drill holes on the working face along the direction parallel to the coal mining face to further determine the fault distribution within the working face.

2. The deep-hole blasting weakening method for an extremely thin fully-mechanized mining face passing through a special-shaped hard fault according to claim 1, characterized in that, In Step 2, before designing the boreholes, first determine the blasting fragmentation range and blasting height, and select the blast hole opening angle, the number of blast holes, and the blast hole arrangement method according to the blasting fragmentation range, blasting height, and the blasting fracture zone radius of the explosives.

3. A deep-hole blasting weakening method for an extremely thin fully-mechanized mining face passing through an abnormally hard fault according to claim 2, characterized in that The calculation formula for the blasting fracture zone radius of the explosives is: Among them, R p is the radius of the explosive fracture circle, P is the peak value of the initial radial stress of the stress wave, r b is the hole radius, S t is the tensile strength of the rock mass, v is the Poisson's ratio, and α is the stress wave attenuation value.

4. A deep-hole blasting weakening method for an extremely thin fully-mechanized mining face passing through a deformed hard fault according to claim 3, characterized in that The calculation formula for the stress wave attenuation value is: α = 2 - v / (1 - v).

5. A deep-hole blasting weakening method for an extremely thin fully-mechanized mining face passing through a deformed hard fault according to claim 1, characterized in that In Step 3, the explosives include a cartridge and a primer. When filling, first use a hole exploration pipe to detect the length of the blast hole, determine the explosive filling length according to the blast hole length, and then sequentially fill the cartridge into the blast hole through the hole exploration pipe. After the cartridge filling is completed, fill the primer.

6. A deep-hole blasting weakening method for an extremely thin fully-mechanized mining face passing through a special-shaped hard fault according to claim 5, characterized in that The cartridge is provided with anti-slip threads.

7. A deep-hole blasting weakening method for an extremely thin fully-mechanized mining face passing through a special-shaped hard fault according to claim 5, characterized in that The manufacturing method of the primer is: select a cartridge, remove the end cap of the cartridge, drill two small holes in the end cap, thread a gummed wire through the holes and tie a knot to fix it, connect the two gummed wires to two detonators respectively, and fix the end cap to the cartridge to complete the production.

8. A deep-hole blasting weakening method for an extremely thin fully-mechanized mining face passing through a deformed hard fault according to claim 5, characterized in that, In Step 3, when sealing the blast hole, use grouting to seal the hole. Insert the grouting pipe and the return slurry pipe into the blast hole, and block the blast hole opening with a plug. Both the grouting pipe and the return slurry pipe penetrate through the plug. The end of the grouting pipe located inside the blast hole is close to the blast hole opening. The other end of the grouting pipe is connected to a grouting pump. The end of the return slurry pipe located inside the blast hole is connected to a return slurry pipe head, and the return slurry pipe head is fixed to the primer. The other end of the return slurry pipe extends out of the plug.

9. A deep-hole blasting weakening method for an extremely thin fully-mechanized mining face passing through a deformed hard fault according to claim 7, characterized in that Before manufacturing the primer, check the resistance of the detonator. The resistance error of the detonator does not exceed 0.2 Ω.

10. A deep-hole blasting weakening method for an extremely thin fully-mechanized mining face passing through a deformed hard fault according to claim 8, characterized in that A gate valve is provided at the slurry outlet of the grouting pump. The outlet end of the gate valve is fixedly connected and communicated with a first quick connector. The end of the grouting pipe extending out of the blast hole is fixedly connected and communicated with a second quick connector. The first quick connector and the second quick connector are adapted and detachably connected.

Images