Method for draining water hazard of coal mine goaf near goaf

Abstract

The application discloses a coal mine old goaf water disaster drainage method crossing adjacent goafs. The application is suitable for the following scene: goaf one, goaf two and goaf three are arranged on one side of a roadway in sequence, a directional drilling mechanism is arranged between the roadway and the goaf two and the goaf three, the directional drilling mechanism passes through a coal seam floor at the bottom of the goaf and is connected to the goaf two and the goaf three, the directional drilling mechanism comprises a directional drilling hole one and a directional drilling hole two, the directional drilling hole one is connected to the goaf two, the directional drilling hole two is connected to the goaf three, and a casing structure is arranged in the directional drilling hole one. The directional drilling hole passes through the coal seam floor and realizes drilling across the adjacent goaf, the range of the old goaf and the length of the drilling hole are increased, the remaining goaf water which cannot be drained by the traditional drilling method in the coal mine is drained in advance, the application can be popularized and used in the field of coal mines and solves the threat of the old goaf water to the coal mine production.

Description

Technical Field

[0001] This invention relates to the field of coal mine old goaf water hazard prevention and control technology, specifically to a method for venting coal mine old goaf water hazards that cross adjacent goaf areas. Background Technology

[0002] Mine water hazards have always been a major factor restricting safe coal production in my country. Statistics show that 60% of mine accidents are related to groundwater, and mine water hazard accidents account for a high proportion of major and serious coal mine accidents in my country. Water inflow into mines in various forms not only causes production losses and casualties and leads to various negative environmental effects, but also threatens the normal extraction of large amounts of coal resources.

[0003] The old workings (i.e., goaf areas) within and around the mining area are the main sources of water hazards, and water inrush accidents mainly originate from water accumulation in these old workings. Water exploration and drainage are effective measures to prevent water inrush accidents, and coal mines must do a good job in water exploration and drainage.

[0004] Currently, the main method for preventing and controlling water in old workings is to use conventional rotary drilling rigs to pre-explore and release water from these workings, eliminating their threat to coal mine production. However, current conventional methods can only explore and release water from the adjacent goaf on one side of the coal pillar in the roadway. Figure 1 The goaf 1-2 shown is located near the coal pillar in the roadway, making advance detection and drainage relatively convenient. However, if waterlogging is severe, water accumulation in other goaf areas cannot be drained in time, thus posing a safety hazard. Furthermore, it is currently impossible to conduct water detection and drainage across adjacent goaf areas. Figure 1 The examples shown are goaf 2 (3) and goaf 3 (4). Furthermore, conventional drilling methods result in short borehole lengths, and the drilling trajectory is prone to deviating from design parameters, making it difficult to accurately reach the designed target strata.

[0005] Therefore, considering the above-mentioned defects, the designers of this invention, based on comprehensive underground field construction tests, and addressing the shortcomings of traditional underground old workings water exploration and drainage methods, researched and designed a coal mine old workings water hazard drainage device and drainage method that crosses adjacent goaf areas, in order to overcome the above-mentioned defects. Summary of the Invention

[0006] The technical problem to be solved by this invention is: how to solve the problem that it is currently impossible to cross adjacent goaf areas to drain the water accumulated in other goaf areas.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] This invention discloses a drainage method for a coal mine old workings water hazard drainage device that crosses adjacent goaf areas, comprising the following steps:

[0009] S1. Calculate the critical value l of hydraulic connection between adjacent goaf areas using the formula;

[0010] S2. Arrange the drilling site according to the required conditions, and then construct the sedimentation tank;

[0011] S3. If the coal pillar thickness is less than the critical value l for hydraulic connection between adjacent goaf areas calculated in step S1, it is determined that the old goaf water in goaf area 2 and goaf area 3 are hydraulically connected, and only directional borehole 1 is constructed; if the coal pillar thickness is greater than the critical value l for hydraulic connection between adjacent goaf areas calculated in step S1, it is determined that the coal pillar completely blocks the old goaf water in goaf area 2 and goaf area 3, and the two goaf areas are not hydraulically connected, and directional borehole 2 needs to be constructed, that is, directional borehole 1 and directional borehole 2 are constructed respectively.

[0012] S4. After the first directional borehole is constructed, a water-stopping casing is installed in the first directional borehole and cement is used to solidify the hole and wait for it to harden. The pressure test is then conducted until the pressure test is qualified.

[0013] S5. After drilling is completed, measure the water output from the borehole. If the water output decreases, proceed with drilling to achieve a through-hole.

[0014] As a further aspect of the present invention: the formula for the critical value l of hydraulic connection between adjacent goaf areas in step S1 is as follows:

[0015]

[0016] In the formula: a is the transformation radius of the working face; μ is Poisson's ratio; E is the shear strength of the coal; The critical value l for hydraulic connection between adjacent goaf areas is calculated based on the water pressure. The calculation result serves as the basis for drilling construction in step S3.

[0017] As a further aspect of the present invention: the trajectories of both the first directional borehole and the second directional borehole are U-shaped trajectories.

[0018] As a further aspect of the present invention: the construction method of the first directional borehole is as follows:

[0019] A1. First, take a large-diameter drill bit and set the drilling angle of the drill bit to -10°.

[0020] A2. When drilling to a depth of 10m-20m, a water-stopping casing is installed in the hole. The casing is 8-10m long and a flange, pressure gauge and high-pressure gate valve are installed on the casing.

[0021] A3. The outer wall of the waterstop sleeve is fixed with polyurethane perforation and sealed with cement.

[0022] A4. After the drill rod enters the expected bottom plate position of the goaf area, adjust the drill rod to tilt, and gradually turn the drilling angle from horizontal to the top. The final drilling inclination angle is +10°.

[0023] As a further aspect of the present invention: the construction method of the second directional borehole is as follows:

[0024] B1. First, take a large-diameter drill bit and set the drilling angle of the drill bit to -10°.

[0025] B2. When drilling to a depth of 10-20m, a water-stopping casing is installed in the hole. The casing is 8-10m long and a flange, pressure gauge and high-pressure gate valve are installed on the casing.

[0026] B3. The outer wall of the waterstop sleeve is fixed with polyurethane perforation and sealed with cement.

[0027] B4. After the drill rod enters the expected bottom plate position of the goaf, adjust the drill rod to tilt and gradually turn the drilling angle from horizontal to the top. The final drilling inclination angle is +10.

[0028] B5. If the drilling rig's feed pressure suddenly drops or suddenly becomes 0, it is determined that the drill has entered the goaf area three, and drilling should be stopped at this time.

[0029] As a further aspect of the present invention: the operation method for sealing and pressure testing the water-stop sleeve in step S4 is as follows:

[0030] S41. After the hole has solidified for 48 hours, water is injected into the hole using a mud pump to pressurize it and maintain the pressure at 2.5 MPa for 30 minutes.

[0031] S42. Then observe whether there is water leakage on the hole wall and near the hole opening;

[0032] S43. If there is no leakage or the pressure drop is ≤0.5MPa within 30 minutes, the grouting is considered qualified. If leakage occurs or the pressure drop is >0.5MPa, grouting should continue until the pressure test is qualified.

[0033] As a further aspect of the present invention: the applicable scenarios of this method include goaf 1, goaf 2 and goaf 3 sequentially located on one side of the roadway, wherein a directional drilling mechanism is opened between the roadway and goaf 2 and goaf 3, and the directional drilling mechanism passes through the coal seam floor located at the bottom of the goaf and connects to goaf 2 and goaf 3.

[0034] The directional borehole includes directional borehole one and directional borehole two. directional borehole one connects to goaf area two and directional borehole two connects to goaf area three. Both directional borehole one and directional borehole two are equipped with casing structures.

[0035] As a further aspect of the present invention: the first directional borehole is connected to the second directional borehole, and the second directional borehole is connected to the end of the first directional borehole, and a sleeve structure is also provided inside the second directional borehole.

[0036] As a further embodiment of the present invention: the second directional borehole is located below the first directional borehole, and the two are arranged side by side.

[0037] As a further aspect of the present invention: the casing structure includes a water-stopping casing installed in directional borehole one and directional borehole two, wherein a flange, a pressure gauge and a high-pressure gate valve are installed on the water-stopping casing.

[0038] Compared with the prior art, the beneficial effects of the present invention are:

[0039] I. This invention employs directional drilling, which penetrates the coal seam floor to cross adjacent goaf areas, increasing the exploration range and drilling length of old goaf areas. It can proactively drain water accumulated in other goaf areas that cannot be drained by traditional drilling methods in coal mines. This invention can be widely used in the coal mining industry to solve the current threat of old goaf water to coal mine production.

[0040] II. This invention calculates the critical connecting coal pillar thickness *l* using a formula. The calculation result serves as the design basis for borehole construction. If the coal pillar thickness is less than the critical hydraulic connection value *l* between adjacent goaf areas, it is determined that the old goaf water in goaf area 2 and goaf area 3 are hydraulically connected, and only directional borehole 1 is constructed. If the coal pillar thickness is greater than the critical hydraulic connection value *l* between adjacent goaf areas, it is determined that the old goaf water in goaf area 2 and goaf area 3 are not hydraulically connected, and the coal pillar completely blocks the water accumulation in the adjacent goaf areas. In this case, directional borehole 2 needs to be constructed to drain the water accumulation in goaf area 2 and goaf area 3 respectively. Using the above method can improve the accuracy and safety of boreholes crossing adjacent goaf areas. The theoretical formula calculation avoids aimless borehole design.

[0041] Third, this invention installs a water-stopping sleeve in the directional borehole and solidifies it to ensure its stability. Then, water is injected into the borehole using a mud pump to pressurize it and detect leakage at the borehole wall and orifice. If leakage occurs or the pressure drop is >0.5MPa, grouting and solidification of the borehole must continue until the pressure test is qualified. The above operation can ensure the stable and safe installation of the water-stopping sleeve and prevent leakage from affecting subsequent work.

[0042] IV. The second stage of drilling in this invention targets the sandstone floor of the coal seam. The drilling trajectory is 10-20m away from the normal distance of the coal seam floor. The sandstone is soft, which makes it less likely for the drilling trajectory to deviate during drilling. The drilling speed is fast and the efficiency is higher than other strata. It is also less likely to cause the drill to get stuck. If the drilling distance from the normal distance of the coal seam floor is too close, it is easy to accidentally penetrate the coal seam during the drilling process. If the drilling distance from the normal distance of the coal seam floor is too far, it is easy to get too far away from the coal seam. If the distance is too close or too far, it will be impossible to accurately enter the target goaf area. Therefore, it is advisable to control the target stratum to be 10 to 20m away from the coal seam floor. Attached Figure Description

[0043] Figure 1 This is a scene diagram before construction in an embodiment of the present invention;

[0044] Figure 2 This is a schematic diagram of a directional drilling construction scenario according to an embodiment of the present invention;

[0045] Figure 3 This is an operational flowchart of the coal mine old goaf water hazard drainage device that crosses adjacent goaf areas according to an embodiment of the present invention;

[0046] Figure 4 This is a schematic diagram of the sleeve structure according to an embodiment of the present invention;

[0047] Explanation of reference numerals in the attached diagram: 1. Roadway; 2. Goaf 1; 3. Goaf 2; 4. Goaf 3; 5. Coal pillar; 6. Directional borehole 1; 7. Directional borehole 2; 8. Coal seam floor; 9. Flange; 10. Pressure gauge; 11. High-pressure gate valve; 12. Water-stop sleeve. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0049] Example 1

[0050] Reference Figure 1 and Figure 2 A method for draining water hazards from old coal mine workings that cross adjacent goaf areas. This method is applicable to scenarios including goaf 1 2, goaf 2 3, and goaf 3 4 located sequentially on one side of roadway 1. A directional borehole 1 6 is drilled between goaf 2 3 and roadway 1 for drainage, and a directional borehole 2 7 is drilled between goaf 3 4 and roadway 1 for drainage. The directional borehole 2 7 is located below the directional borehole 1 6, and the two are set side by side. A water-stopping sleeve 12 is installed inside the directional borehole 1 6.

[0051] It should be noted that the water-stop sleeve 12 is equipped with a flange 9, a pressure gauge 10 and a high-pressure gate valve 11. The pressure gauge 10 is used to test the water pressure inside the sleeve, and the high-pressure gate valve 11 is used to control the flow rate of water in the sleeve.

[0052] The specific operating principle of the coal mine water hazard drainage device that crosses the adjacent goaf area is as follows:

[0053] Step 1: Calculate the critical value of hydraulic connection between adjacent goaf areas. The critical value of hydraulic connection between adjacent goaf areas is derived using the following formula:

[0054]

[0055] In the formula: a is the transformation radius of the working face; μ is Poisson's ratio; E is the shear strength of the coal; The critical value l for hydraulic connection between adjacent goaf areas is calculated based on the water pressure. The calculation result serves as the basis for drilling construction in step three.

[0056] In this embodiment, 'a' is taken as the conversion radius of the working face (the length of the coal mine working face in this embodiment is taken as 2000m, the height of the roadway is taken as 5m, and the calculated value of 'a' for the roadway rock wall area is 60m); μ is taken as 0.3; the shear strength of the coal is taken as 0.3MPa; the water pressure P is calculated as l=12.75m based on the maximum water pressure P measured on-site in the coal mine in this embodiment, which is 0.7MPa.

[0057] Step 2: Arrange the drilling site and construction sedimentation basin:

[0058] The drilling site space must meet the following conditions: 1. There must be more than 12m of space in the longitudinal direction of the drilling rig to facilitate loading and unloading of drill rods; 2. There must be more than 6m of space in the transverse direction of the drilling rig to facilitate drilling operations; the drilling site layout should be 12m long, 6m wide, and the height should be the same as the roadway height.

[0059] Directional drilling requires a level drilling floor. Considering the drilling water demand, the water supply capacity is set at 12m. 3 / h configuration, equipped with two power supplies of 660 / 1140V and 127V, with a total power of ≥110kW, and the cable specifications and models meet the total power requirements.

[0060] Construction of sedimentation tank: The sedimentation tank is required to be 2m (length) × 2m (width) × 1m (depth), connected to the drainage system, and equipped with a drainage pump with a capacity of not less than 1.5 times the expected drainage volume.

[0061] Step 3: Construction of the first section of the directional drilling structure:

[0062] If the coal pillar thickness (the actual coal pillar thickness between goaf 2 (3) and goaf 3 (4)) is less than the critical value l for hydraulic connection between adjacent goafs calculated in step one (12.75m in this embodiment), it is determined that the old goaf water in goaf 2 (3) and goaf 3 (4) is interconnected, and only the first section of the directional borehole 1 needs to be constructed. If the coal pillar thickness is greater than the critical value l for hydraulic connection between adjacent goafs (12.75m in this embodiment), it is determined that the old goaf water in goaf 2 and goaf 3 is not hydraulically interconnected, and the water in the two goafs is blocked by the coal pillar. Therefore, the first section of the directional borehole 2 needs to be constructed, i.e., the first section of directional borehole 1 (6) and directional borehole 2 (7) need to be constructed respectively. It should be noted that the construction methods for directional borehole 1 (6) and directional borehole 2 (7) are the same.

[0063] The specific construction method for the first section of the directional drilling structure is as follows:

[0064] First, using a large-diameter drill bit (drill bit diameter Φ193mm), the drilling rod is set to an inclination angle of -10°. When drilling to a depth of 10m-20m, a water-stopping sleeve 12 is installed in the hole. The sleeve is 8-10m long. A flange 9, a pressure gauge 10, and a high-pressure gate valve 11 are installed on the sleeve. The outer wall of the water-stopping sleeve 12 is fixed with polyurethane hole wall and sealed with cement.

[0065] Step 4: Install and seal the water-stop sleeve and perform a pressure test.

[0066] After the 12 water-stop sleeve has been solidified for 48 hours, water is injected into the hole using a mud pump to pressurize it, maintaining a pressure of 2.5 MPa for 30 minutes. Observe the hole wall and the vicinity of the pipe for any leakage. If there is no leakage or the pressure drop is ≤0.5 MPa within 30 minutes, the solidification is considered successful. If leakage occurs or the pressure drop is >0.5 MPa, grouting and solidification should continue until the pressure test is successful.

[0067] Step 5: Second stage of directional drilling

[0068] The specific construction method for the first section of the directional drilling structure is as follows:

[0069] The second stage of the structure begins by using a small-diameter drill bit (Φ98mm) to maintain the drill rod's opening angle at -10°. After drilling into the coal seam floor, the drill rod is adjusted to be horizontal, and the drilling angle gradually changes from inclined to horizontal. When drilling reaches a depth of 10-20m, the drill rod enters the expected floor position of goaf 3-4. The drill rod is then adjusted to be inclined, and the drilling angle gradually changes from horizontal to the top, with the final drilling angle set at +10°. If the drill rig's feed pressure suddenly drops or becomes zero, it indicates entry into goaf 3-4. Drilling is then stopped. If goaf 2-3 and goaf 3-4 are rich in water, the water return from the borehole increases, and the water discharge is recorded.

[0070] It is important to note that the target stratum for the second stage of structural drilling is the rock stratum below the coal seam floor 8, preferably sandstone. The borehole trajectory should be 10-20m from the normal distance of the coal seam floor, preferably 10m. The reasons are as follows: Sandstone is soft, which makes it less likely for the borehole trajectory to deviate during drilling, resulting in faster drilling speed and higher efficiency than other strata, and reducing the risk of stuck drills. If the borehole is too close to the normal distance of the coal seam floor 8, it may accidentally penetrate the coal seam during drilling. If the borehole is too far from the normal distance of the coal seam floor 8, it may stray too far from the coal seam. Neither too close nor too far from the normal distance of the coal seam floor 8 can accurately enter the target goaf area. Therefore, it is advisable to control the target stratum to be 10 to 20m from the coal seam floor, preferably 10m.

[0071] The trajectories of directional drilling hole 1-6 and directional drilling hole 2-7 are both set to U-shaped trajectories (e.g., Figure 2As shown in the figure, a U-shaped directional drilling trajectory is adopted. The directional borehole penetrates into and out of the coal seam floor, so as to cross the adjacent goaf area, increase the exploration range of old goaf area and the length of the borehole, and carry out advance drainage of water in other goaf areas that cannot be drained by traditional drilling methods in coal mines.

[0072] It is important to note that the borehole design consists of two sections. The borehole diameter of the first section must be larger than that of the second section; otherwise, after the casing is installed in the first section, the drill bit for the second section will be unable to enter the hole due to the smaller borehole diameter. In this embodiment, the drill bit diameter for the first section is Φ193mm, and after drilling to a depth of 10m, a water-stop casing 12 is installed. Its main purpose is to seal the formation at the borehole opening and install the borehole opening device. The second section is a bare-hole directional section. The drill bit diameter for the second section is Φ98mm. The drilling trajectory of the second section is monitored and adjusted using a measurement-while-drilling (MWD) instrument to ensure it follows the designed trajectory. The combined drilling trajectory of the first and second sections is a U-shaped trajectory, as shown in the diagram. Figure 2 middle.

[0073] Step Six, Through Hole:

[0074] After drilling is completed, the water discharge borehole in the goaf is easily blocked by silt and gravel, causing the water output to gradually decrease after drilling is pulled out. If the water output decreases during the pulling-out process, the borehole must be drilled again. After pulling out the drill rod, the water output should be measured first, and then the high-pressure gate valve 11 should be closed to observe the water pressure. If the water output decreases again during the drainage process, drilling should continue.

[0075] Example 2

[0076] The rest is the same as above, except that: directional borehole 6 is connected to directional borehole 7, and directional borehole 7 is connected to the end of directional borehole 6. directional borehole 7 is a branch of directional borehole 6. directional borehole 7 is also equipped with a water-stop sleeve 12 structure.

[0077] When excavating directional borehole 27, drilling should continue using drill rods based on directional borehole 16 until the drill rods reach the expected bottom position of goaf 34. Then, the drill rods should be adjusted to be inclined, and the drilling angle should gradually turn from horizontal to top. The final borehole inclination angle should be +10°. If the feed pressure of the drilling rig suddenly drops or suddenly becomes 0, it is determined that goaf 34 has been entered, and drilling should be stopped at this time.

[0078] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. 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 of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for draining water hazards from old coal mine workings that cross adjacent goaf areas, characterized in that, Includes the following steps: S1. Calculate the critical value l of hydraulic connection between adjacent goaf areas using the formula; The formula for the critical value l of hydraulic connection between adjacent goaf areas is as follows: In the formula: a is the transformation radius of the working face; μ is Poisson's ratio; E is the shear strength of the coal; The critical value l for hydraulic connection between adjacent goaf areas is calculated based on the water pressure. The calculation result is used as the basis for drilling construction in step S3. S2. Arrange the drilling site according to the required conditions, and then construct the sedimentation tank; S3. If the coal pillar thickness is less than the critical value l for hydraulic connection between adjacent goaf areas calculated in step S1, it is determined that the old goaf water in goaf area 2 and goaf area 3 are hydraulically connected, and only directional borehole 1 is constructed; if the coal pillar thickness is greater than the critical value l for hydraulic connection between adjacent goaf areas calculated in step S1, it is determined that the coal pillar completely blocks the old goaf water in goaf area 2 and goaf area 3, and the two goaf areas are not hydraulically connected, and directional borehole 2 needs to be constructed, that is, directional borehole 1 and directional borehole 2 are constructed respectively. S4. After the first directional borehole is constructed, a water-stopping casing is installed in the first directional borehole and cement is used to solidify the hole and wait for it to harden. The pressure test is then conducted until the pressure test is qualified. S5. After drilling is completed, measure the water output from the borehole. If the water output decreases, proceed with drilling to achieve a through hole. The applicable scenarios for this method include goaf 1, goaf 2 and goaf 3 set sequentially on one side of the roadway, with a directional drilling mechanism opened between the roadway and goaf 2 and goaf 3, the directional drilling mechanism passing through the coal seam floor located at the bottom of the goaf and connecting to goaf 2 and goaf 3. The directional borehole includes directional borehole one and directional borehole two. directional borehole one connects to goaf area two and directional borehole two connects to goaf area three. Both directional borehole one and directional borehole two are equipped with casing structures.

2. The method for draining water hazards from old coal mine workings across adjacent goaf areas according to claim 1, characterized in that: Both the first and second directional boreholes have U-shaped trajectories.

3. The method for draining water hazards from old coal mine workings across adjacent goaf areas according to claim 1, characterized in that: The construction method for the first directional borehole is as follows: A1. First, take a large-diameter drill bit and set the drilling angle of the drill bit to -10°. A2. When drilling to a depth of 10m-20m, a water-stopping casing is installed in the hole. The casing is 8-10m long and a flange, pressure gauge and high-pressure gate valve are installed on the casing. A3. The outer wall of the waterstop sleeve is fixed with polyurethane perforation and sealed with cement. A4. After the drill rod enters the expected bottom plate position of the goaf area, adjust the drill rod to tilt and gradually turn the drilling angle from horizontal to the top. The final drilling inclination angle is +10°. A5. If the drilling rig's feed pressure suddenly drops or suddenly becomes 0, it is determined that the drill has entered the second goaf area, and drilling should be stopped at this time.

4. The method for draining water hazards from old coal mine workings across adjacent goaf areas according to claim 1, characterized in that: The construction method for the second directional borehole is as follows: B1. First, take a large-diameter drill bit and set the drilling angle of the drill bit to -10°. B2. When drilling to a depth of 10-20m, a water-stopping casing is installed in the hole. The casing is 8-10m long and a flange, pressure gauge and high-pressure gate valve are installed on the casing. B3. The outer wall of the waterstop sleeve is fixed with polyurethane perforation and sealed with cement. B4. After the drill rod enters the expected bottom plate position of the goaf, adjust the drill rod to tilt and gradually turn the drilling angle from horizontal to the top. The final drilling inclination angle is +10. B5. If the drilling rig's feed pressure suddenly drops or suddenly becomes 0, it is determined that the drill has entered the goaf area three, and drilling should be stopped at this time.

5. The method for draining water hazards from old coal mine workings across adjacent goaf areas according to claim 1, characterized in that: The operation method for sealing and pressure testing the water-stop sleeve in step S4 is as follows: S41. After the hole has solidified for 48 hours, water is injected into the hole using a mud pump to pressurize it and maintain the pressure at 2.5 MPa for 30 minutes. S42. Then observe whether there is water leakage on the hole wall and near the hole opening; S43. If there is no leakage or the pressure drop is ≤0.5MPa within 30 minutes, the grouting is considered qualified. If leakage occurs or the pressure drop is >0.5MPa, grouting should continue until the pressure test is qualified.

6. The method for draining water hazards from old coal mine workings across adjacent goaf areas according to claim 1, characterized in that: The first directional borehole is connected to the second directional borehole, and the second directional borehole is connected to the end of the first directional borehole. The second directional borehole is also equipped with a casing structure.

7. The method for draining water hazards from old coal mine workings across adjacent goaf areas according to claim 1, characterized in that: The second directional borehole is located below the first directional borehole, and the two are arranged side by side.

8. The method for draining water hazards from old coal mine workings across adjacent goaf areas according to claim 1, characterized in that: The casing structure includes a water-stopping casing installed in directional borehole one and directional borehole two, wherein a flange, a pressure gauge and a high-pressure gate valve are installed on the water-stopping casing.

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