A method for hydraulic coal mining in an ultra-steeply inclined coal seam

Abstract

This invention discloses a method for hydraulic mining of ultra-steep and steeply inclined coal seams using boreholes, relating to the field of coal mining technology. The method includes a roadway layout in the mining area, with roadway modules arranged in the pseudo-incline uphill and longwall mining face roadways of the steeply inclined coal seam. The borehole hydraulic mining module includes boreholes and a borehole hydraulic mining system, with a drilling water gun fixed to the top of the drill rod. High-pressure water jets generated by the drilling water gun are used to break up the coal body around the borehole, achieving hydraulic mining. The coal and water transport module includes a coal and water gravity flow channel and a gravity flow trench. A flexible protective net is used to isolate the goaf and protect the coal face and the coal and water gravity flow channel. Therefore, this method requires only the lower roadway drilling rig operator, enabling unmanned operation of the coal face and providing a new technical approach for the safe and efficient mining of steeply inclined coal seams.

Description

Technical Field

[0001] This invention relates to the field of coal mining technology, and more specifically, to a method for drilling hydraulic coal mining in ultra-steep and steeply inclined coal seams. Background Technology

[0002] The technology for mining steeply inclined coal seams has gone through three stages: The first stage mainly relied on manual blasting, such as the inverted bench mining method, which was labor-intensive, extremely inefficient, and had a single-unit output of less than 200,000 tons / year, and has been phased out; The second stage mainly applied technologies such as pseudo-inclined flexible shield supports and horizontal layered mining methods, which reduced some labor intensity, but the mechanization level was still less than 30%, and the accident rate was 3-5 times that of gently inclined coal seams; The third stage is the exploration stage of comprehensive mechanization and intelligentization. Some enterprises have applied comprehensive mechanized mining technology to coal seams with dip angles of 55°-68° by improving the stability of fully mechanized mining supports (such as adding anti-tipping and anti-slip devices). However, for ultra-steep and steeply inclined coal seams with dip angles >60°, the stability of fully mechanized mining supports is extremely difficult to control, and overturning and sliding accidents are prone to occur. In addition, the workers need to be in close contact with the exposed coal body at the working face, facing multiple risks such as roof collapse, side spalling, and gas outburst, and production efficiency is also difficult to improve.

[0003] Traditional hydraulic coal mining technology, due to its integrated advantages of "breaking, transporting, and lifting", was promoted and applied in the mining of gently inclined coal seams after the 1980s. However, it has been gradually phased out due to its high roadway excavation rate, unreliable ventilation system, high safety risks, and low recovery rate. It has also failed to be promoted in the mining of steeply inclined coal seams.

[0004] In summary, how to achieve "safe, efficient, and low-cost" mining of steeply inclined coal seams, especially ultra-steeply inclined coal seams, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a hydraulic coal mining method for drilling in ultra-steeply inclined coal seams, so as to improve the mining efficiency and safety of steeply inclined coal seams.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for hydraulic coal mining with boreholes in ultra-steeply inclined coal seams includes the following steps:

[0008] In the middle of the steeply inclined coal seam mining area, a reversible transport uphill roadway and a return air uphill roadway are arranged in a pseudo-inclination. The return air uphill roadway is connected to the main return air roadway of the mining area. On both sides of the transport uphill roadway and the return air uphill roadway, several roadways connected to the transport uphill roadway and the return air uphill roadway are arranged according to a preset height using water excavation and water transport methods. This divides the steeply inclined coal seam mining area into several mining sections. The first mining face is located at the uppermost part of the steeply inclined coal seam mining area, and mining is carried out from top to bottom section by section. The roadway at the bottom of the previous mining section is used as the upper roadway return air roadway of the next mining section to reduce the amount of roadway excavation work.

[0009] Drilling is carried out along the dip direction of the coal seam at the boundary of the mining section. The drilled holes connect the roadways at the top and bottom of the mining section to form a full negative pressure ventilation system for the mining face.

[0010] A flexible protective net is laid on the bottom plate of the roadway at the top of the mining section, and it is lowered synchronously with the coal mining operation to the upper side stop mining position of the roadway at the bottom of the mining section.

[0011] In the mining section, water-mining boreholes are constructed sequentially towards the transport uphill roadway to divide the mining section into several coal mining blocks. Drill rods are inserted into the boreholes, and a drilling water gun is installed at the top of the drill rod. The end of the drill rod is connected to a high-pressure water supply system. The drilling rig drives the drill rod to swing slowly, and the high-pressure water jet generated by the drilling water gun strikes and breaks the surrounding coal body radially along the borehole to form a coal-water mixture, thereby realizing hydraulic coal mining.

[0012] The coal-water mixture flows down the sidewall of the borehole or goaf to the bottom of the mining section of the roadway, from where it flows by gravity to the transport uphill roadway, and then to the main roadway centralized treatment station. The coal-water slurry is then pumped by a coal slurry pump to the raw coal pool of the surface coal washing plant.

[0013] Furthermore, in this invention, a drill rod is inserted into the borehole, and a drilling water gun is installed at the top of the drill rod. Its end is connected to a high-pressure water supply system. The drill rig drives the drill rod to slowly oscillate, and the high-pressure water jet generated by the drilling water gun strikes and breaks up the surrounding coal body radially along the borehole, forming a coal-water mixture, thereby achieving the following in hydraulic coal mining:

[0014] The drilling rig drives the drill rod to move gradually towards the bottom of the coal mining section so that the drilling water gun breaks the coal body around the borehole in a step manner, and the height of a single step is 0.1 to 0.5 meters.

[0015] Furthermore, the pressure of the drilling water gun is adjustable within the range of 10-30 MPa.

[0016] Furthermore, the flexible protective net is one of double-layer diamond wire mesh, nylon, or plastic mesh.

[0017] Furthermore, in this invention, the coal-water mixture flows down the sidewall of the borehole or goaf to the bottom of the mining section via the haulage roadway, and then flows by gravity through the transport uphill roadway to the main roadway centralized treatment station, where a coal slurry pump lifts the coal-water slurry to the raw coal pool of the surface coal washing plant.

[0018] The excess clean water after sedimentation in the surface raw coal pool and the centralized treatment station in the underground main roadway is returned to the suction pool of the drilling and production high-pressure pump to achieve water resource recycling.

[0019] Furthermore, the invention uses the roadway at the bottom of the previous mining section as the upper roadway return airway for the next mining section to reduce the amount of roadway excavation work.

[0020] The mining roadway is equipped with a lower roadway for transporting coal-water mixture. The lower roadway is connected to the transport uphill roadway and has an inclination angle of 3° to 5°, so that the mining roadway can transport the coal-water mixture to the transport uphill roadway by gravity.

[0021] Furthermore, in this invention, a drill rod is inserted into the borehole, and a drilling water gun is installed at the top of the drill rod. Its end is connected to a high-pressure water supply system. The drill rig drives the drill rod to slowly oscillate, and the high-pressure water jet generated by the drilling water gun strikes and breaks up the surrounding coal body radially along the borehole, forming a coal-water mixture, thereby achieving the following in hydraulic coal mining:

[0022] Single-sided drilling and mining or double-sided drilling and mining can be selected according to the difficulty of roof management in the mining section.

[0023] Furthermore, in the present invention, the drilling water gun only swings horizontally within a 180° range to one side of the goaf during single-sided drilling and mining, and utilizes the space between the coal wall on the goaf side and the flexible protective net as a coal-water flow channel.

[0024] During the dual-sided drilling and extraction process, the drilling and extraction water gun swings horizontally within a 360° range, and by increasing the borehole diameter, the borehole serves as a self-flowing channel for coal and water.

[0025] Furthermore, when single-sided drilling is used, the nozzle of the drilling water gun has a downward angle of 8° to 10° with respect to the radial direction of the borehole; when double-sided drilling is used, the nozzle of the drilling water gun has an upward angle of 8° to 10° with respect to the radial direction of the borehole.

[0026] Furthermore, the drill pipe has an integrated optical cable channel for transmitting monitoring signals, and the drilling water gun is equipped with a monitoring probe, which is connected to a remote monitoring system via an optical cable located within the optical cable channel.

[0027] The present invention provides a hydraulic coal mining method for ultra-steeply inclined coal seams. In the middle of the steeply inclined coal seam mining area, a pseudo-inclined, reversible haulage incline roadway and return air incline roadway are arranged. Several roadways connecting to the haulage incline roadway and return air incline roadway are arranged on both sides of the haulage incline roadway and return air incline roadway, dividing the steeply inclined coal seam mining area into several mining sections. A flexible protective net is laid on the top of the mining section and allowed to sink synchronously with the coal mining operation to the upper side of the roadway at the bottom of the mining section where mining stops. Water-operated drilling holes are sequentially drilled in the mining section towards the haulage incline roadway to divide the mining section into several coal block segments. A drill rod is inserted into the drill hole, and a drilling water gun is installed at the top of the drill rod. The high-pressure water supply system is connected to the end of the drilling rig. The drill rod is slowly oscillating, and the high-pressure water jet generated by the drilling water gun is used to hit and break the surrounding coal body radially along the borehole to form a coal-water mixture, thus realizing hydraulic coal mining. The coal-water mixture flows down the side coal wall of the borehole or the goaf to the roadway at the bottom of the mining section. It is then transported to the incline roadway by the roadway and then flows by gravity to the main roadway centralized treatment station. The coal-water slurry is then pumped to the raw coal pool of the surface coal washing plant. Therefore, the high-risk mining operation is completed by remotely controlling the equipment in the borehole. Personnel only operate the drilling rig and monitoring system in the safe roadway, which fundamentally eliminates the direct threat to personnel from safety hazards such as the roof and gas at the working face.

[0028] Furthermore, this mining system involves less roadway engineering and less equipment investment, resulting in a significant reduction in total investment and production costs. The coal mining face is unmanned, making it safe and efficient. In particular, it has found a safe, efficient, and low-cost technical path for mining ultra-steep and steeply inclined coal seams with an angle greater than 60°.

[0029] Meanwhile, the core of the system does not rely on bulky equipment for stabilizing steep coal seams, so it is highly adaptable to the dip angle of the coal seam, and the greater the dip angle, the more reliable the system.

[0030] It can be applied to thin, medium-thick, and thick coal seams, and it is also highly adaptable to large variations in the thickness of the same coal seam. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the structure during coal seam mining provided by the present invention;

[0033] Figure 2This is a schematic diagram of the front structure of the unidirectional nozzle for coal mining provided by the present invention.

[0034] Figure 3 This is a schematic diagram of the structure of the unidirectional nozzle coal mining side provided by the present invention;

[0035] Figure 4 This is a schematic diagram of the front structure of the bidirectional nozzle coal mining method provided by the present invention.

[0036] Figure 5 This is a schematic diagram of the structure of the bidirectional nozzle coal mining side provided by the present invention;

[0037] Figure 6 This is a schematic diagram of the structure of the thin coal seam mining side provided by the present invention.

[0038] Figures 1-6 In the accompanying drawings, the reference numerals include:

[0039] 1. Steeply inclined coal seam mining area; 2. Transport uphill roadway; 3. Return air uphill roadway; 4. Slot roadway; 5. Mining section; 6. Borehole; 7. Flexible protective net; 8. Coal-water gravity flow channel. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and 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.

[0041] The core of this invention is to provide a hydraulic mining method for drilling in ultra-steep and steeply inclined coal seams, which improves the mining efficiency and safety of ultra-steep and steeply inclined coal seam mining areas.

[0042] Please refer to Figure 1 A method for hydraulic coal mining in ultra-steeply inclined coal seams includes the following steps:

[0043] Firstly, regarding the layout of the mining area roadways, for steeply inclined coal seams with non-coal and gas outbursts, two zigzag uphill roadways are arranged in the middle of the mining area along the coal seam at a pseudo-inclination direction of 23°-25°. These are transport uphill roadway 2 (serving as a coal-water gravity flow channel 8 and auxiliary transportation for materials, equipment, etc.) and return air uphill roadway 3 (serving as underground ventilation). The length of each uphill zigzag roadway is approximately 200-300 meters, and their upper parts are connected to the main return airway of the mining area. On both sides of the mining area, a 5-meter interval is provided. Several mining roadways are arranged with a vertical height of 0-60 meters to divide the mining area into several sections. Under suitable conditions, the vertical height of the sections can reach more than 100 meters. Coal mining adopts the longwall retreat mining technology. The first mining operation is located at the uppermost part of the mining area, and mining is carried out section by section from top to bottom. Water excavation and water transportation are used when tunneling roadways, which helps to simplify the transportation system. The mining roadway above each section is called the upper roadway, and the mining roadway below the section is called the lower roadway.

[0044] When conditions permit, one working face can be set up on each side of the mining area for simultaneous mining. When mining the lower roadway of the previous section, the goaf can be left as the upper roadway (return airway) for mining the next section, so as to reduce the amount of roadway excavation work.

[0045] After the coal mining face has been constructed to the boundary of the mining area, due to the large dip angle of the coal seam, it is difficult to construct the cutting roadway. The cutting side hole can be constructed instead. That is, a large diameter borehole (600-800mm) is constructed along the coal seam upward at the cutting position of the cutting roadway in the lower part of the section to connect with the cutting roadway at the top of the section. Alternatively, a small borehole can be constructed first to connect the sections and then the borehole can be enlarged with a high-pressure water gun, so that a full negative pressure ventilation system can be formed in the working face before coal mining.

[0046] Before formal coal mining, a flexible protective net 7 is laid. The flexible protective net 7 consists of "net, beam, and rope" (fixed to each other with rope clips or U-shaped clips). The flexible protective net 7 can be a double-layer net, diamond wire mesh, or nylon or plastic net, etc. The width of the flexible protective net 7 should exceed the coal seam thickness by more than 1 meter (more than 0.5 meters beyond the top and bottom plates of the coal seam). Support beams are used to increase the strength of the flexible protective net 7. W-shaped steel strips, old rails, old steel pipes, and I-beams can be used as support beams. The length of the support beams is about 0.5 meters shorter than the coal thickness (leaving 0.2-0.3 meters on each side of the top and bottom plates of the coal seam to avoid getting stuck between the top and bottom plates). The spacing between the support beams is about 1.5 meters. Old steel wire ropes with a diameter of more than 20mm can also be used, at least two of them, fixed at 0.2-0.3 meters from both ends of the support beams. If the coal seam thickness exceeds 2.5 meters, steel wire ropes should be added appropriately in the middle.

[0047] The flexible protective net 7 is laid from the top of the side hole all the way to the upper side of the lower roadway and fixed. If space is limited, the protective net inside the hole may not be supported by beams. At least 15 meters of protective net should be pre-laid along the bottom plate of the roadway outside the side hole of the upper roadway. When the coal is thick, it is necessary to expand the side to the top and bottom plate of the coal seam in advance.

[0048] Hydraulic coal mining begins at the edge of the working face and proceeds outwards in sections. First, hydraulic drilling hole 6 is constructed. The drilling rig is located in the lower roadway and drills directionally along the coal seam to the upper roadway. When drilling on both sides, hole 6 needs to be enlarged to 300mm after it is completed so that hole 6 forms a coal-water flow channel 8. When drilling on one side, no enlargement is required. The side hole of the opening or the space of the coal wall on the goaf side is used as a coal chute. After the hydraulic drilling hole 6 is completed, a special drilling water gun and a cable-connected drill rod are replaced. The drilling water gun is then sent to the bottom plate of the upper roadway by the drilling rig. The high-pressure water supply system is connected to the end of the drill rod, the high-pressure pump is started, and the drilling rig is turned on to drive the drill rod to slowly swing and rotate. The high-pressure water jet generated by the drilling water gun is used to strike and break the surrounding coal body radially along the hole 6 to achieve hydraulic coal mining.

[0049] Coal transportation adopts a combined "gravity and pump pressure" transport mode, namely water transport and water lifting. Specifically, the coal-water mixture that is broken by high-pressure water jets at the drilling and mining face flows down the side coal wall of borehole 6 or the goaf to the lower roadway. It then flows by gravity through the roadway and the uphill roadway in the middle of the mining area to the main roadway centralized treatment station. The coal-water slurry is then pumped by coal slurry pumps to the raw coal pool of the surface coal washing plant. At the same time, the excess clean water from the surface raw coal pool and the underground main roadway centralized treatment station is returned to the drilling and mining high-pressure pump suction pool for recycling.

[0050] As the coal mining block advances, the roof of the goaf naturally collapses above the flexible shield net 7 and accumulates in the goaf. The flexible shield net 7 in the upper roadway is laid at least one block length ahead and fixed with supports. As the drilling and mining face of the block gradually moves downward, under the action of the overlying collapsed gangue and its own weight, the flexible shield net 7 descends synchronously, always isolating the coal mining area from the goaf, protecting the normal operation of the water mining in this block. As the water mining face descends, the flexible shield net 7 gradually changes from an initial horizontal state in the upper roadway to a pseudo-inclined state, with the pseudo-inclined angle gradually increasing until it becomes vertical when the mining of this block ends, becoming part of the goaf side coal wall shield net. As the working face advances forward, the flexible shield net 7 eventually sinks to the position where mining stops on the upper side of the lower roadway, becoming a side protection net.

[0051] Depending on the difficulty of managing the coal seam roof, two block drilling methods can be adopted: single-sided drilling or double-sided drilling. Single-sided drilling is used when the roof is fractured and roof control is difficult. In single-sided drilling, the drilling water gun only rotates and swings horizontally within a 180° range towards one side of the goaf to break the coal, and the space between the coal wall on the goaf side and the flexible shield net 7 is used as a coal-water flow channel. The borehole 6 is not enlarged to serve as a coal chute. Figure 2 As shown, double-sided drilling is used when the roof conditions are good. During double-sided drilling, the drilling water gun swings and rotates horizontally within a 360° range, resulting in high mining efficiency and large output. However, the suspended roof area in the goaf is large, and gangue is prone to cross-flow at the working face, and even gangue can block the coal chute. Figure 3 As shown.

[0052] To facilitate the gravity flow of the coal-water mixture broken by high-pressure water jet, during single-sided drilling, the nozzle of the drilling water gun has a downward angle of 8° to 10° relative to the radial direction of borehole 6, and during double-sided drilling, the nozzle of the drilling water gun has an upward angle of 8° to 10° relative to the radial direction of borehole 6.

[0053] The mining operation proceeds in steps from top to bottom along borehole 6. During mining, the drilling rig drives the drill rod to rotate slowly, and the high-pressure water jet from the drill bit's water gun cuts and breaks up all the coal on one or both sides of borehole 6 in sequence. Then the drill rod moves down to the next step, and this cycle continues until the lower part of borehole 6 is near (a 2-meter protective coal pillar is left on the upper side of the roadway). The mining of this section ends, and the mining of the next section begins. The height of the step is determined according to the coal structure, hardness, and actual coal breaking effect, and is 0.1 to 0.5 meters. The width of each mining section in borehole 6 is determined by the depth of the high-pressure water jet breaking the coal radially in borehole 6. If the coal breaking depth is 6 to 8 meters, the width of a single-sided mining section is also 6 to 8 meters, while the width of a double-sided mining section is 12 to 16 meters.

[0054] If, during the double-sided drilling process, the coal chute is blocked by gangue from the goaf, it should be dealt with promptly. A single-sided drilling water gun can be used to temporarily change the flow direction of coal and water in borehole 6 and the goaf side, pushing the blocking gangue into the goaf. Then, double-sided drilling should be resumed until the designed stop position on the upper side of the lower roadway is reached.

[0055] High-pressure hydraulic drilling and production systems include high-pressure pump stations, pipeline systems, drilling rigs, drill rods, and drilling water jets. Their core function is to provide a stable high-pressure water jet to break up coal seams. Specifically, they also include:

[0056] The high-pressure pump station is located in the coal and water centralized treatment station in the underground horizontal main roadway. It consists of three high-pressure plunger pumps (model 3D150-30) connected in parallel, with two in use and one on standby. The flow rate of a single pump is 150 m³ / h, and the pressure is 30 MPa. It is equipped with a frequency conversion control system, which can adjust the pressure according to the hardness of the coal.

[0057] The pipeline system uses Φ200 high-pressure seamless steel pipe (pressure resistance rating 40MPa) for the main pipeline (main roadway and mining area uphill roadway) and Φ150 high-pressure seamless steel pipe for the branch pipeline (sloping roadway). The drill pipe (Φ89mm) is connected to the branch pipe using Φ80 high-pressure hose (polyurethane material, pressure resistance 40MPa). The branch pipe, hose and drill pipe are connected by quick couplings. The branch pipe is spliced ​​in time as the drilling and mining block moves outward.

[0058] The drilling rig is a tracked fully automatic directional drilling rig, mainly used for directional drilling of borehole 6 and borehole enlargement. The drilling rig is a key piece of equipment in the borehole 6 water mining system, responsible for drill rod connection and unloading, water gun installation and fixing, positioning, movement, and rotation driving of coal mining, etc.

[0059] The drilling water gun is a key specialized piece of equipment for drilling water extraction in borehole 6. It is fixedly installed on the top of the drill rod. A single nozzle is used when mining coal on one side, and a double nozzle is used when mining coal on both sides.

[0060] The ventilation system allows air to enter the upper roadway return airway via the uncollapsed space between the lower coal face and the goaf, as well as the goaf above the working face. Due to the air pressure difference, some airflow will also pass through borehole 6.

[0061] The monitoring system is equipped with monitoring probes on the water gun heads, which can remotely monitor and adjust the working status, parameters and coal breaking conditions of the water guns. Alternatively, monitoring devices such as gas and temperature sensors, lighting and high-definition cameras can be suspended from the upper roadway on the side of the coal wall above the drilling and mining face to dynamically monitor the on-site and environmental parameters of the drilling and mining face, and realize remote visual mining.

[0062] The specific implementation method of this ultra-steep and steeply inclined coal seam drilling hydraulic mining method is as follows:

[0063] S1. Layout of mining area roadways: Construct transport uphill roadway 2 and return air uphill roadway 3 in the middle of the mining area. Construct several parallel return mining roadways on both sides of the mining area to divide the mining area into several sections. The first mining operation is located at the top of mining area 1, and the coal mining face is mined from top to bottom.

[0064] S2. Construction of side holes: Drilling holes 6 along the inclined direction, the drilling holes 6 are arranged in the lower and upper roadways of the coal mining face to form a full negative pressure ventilation system for the working face;

[0065] S3, Flexible protective net 7 installation: A flexible protective net 7 composed of net, beam and rope is laid in the side hole of the cut and in the advanced coal block section of the upper roadway, and it is lowered synchronously with the coal mining operation to isolate the goaf and the coal block section.

[0066] S4. Construction of water mining borehole 6: In the lower roadway, which is adjacent to the opening hole and is a drilling and mining block, a directional borehole 6 is constructed using a drilling rig to connect the upper roadway. No hole enlargement is required when drilling and mining on one side, but hole enlargement is required when drilling and mining on both sides, and the borehole also serves as a coal and water gravity flow channel 8.

[0067] S5, Coal-water gravity flow channel 8: The space jointly defined by the goaf side coal wall and the flexible protective net 7 or the borehole 6 serves as the coal-water gravity flow channel 8;

[0068] S6. High-pressure hydraulic drilling: Fix the high-pressure water gun to the top of the drill rod, and move the high-pressure water gun to a predetermined position inside the borehole 6 through the drill rod;

[0069] High-pressure water is delivered to the high-pressure water gun through the drill rod to generate a jet, and the drill rod is driven by the drilling rig to swing along its axis so that the high-pressure water jet breaks the coal body around the borehole 6 at a preset angle.

[0070] S7. Coal slurry conveying: The crushed coal is mixed with water to form a coal-water mixture. Using a set deflection angle, the coal-water mixture flows by gravity through the coal-water gravity flow channel 8, the lower roadway, and the transport uphill roadway 2 to the main roadway centralized treatment station, where it is pumped to the surface by a coal slurry pump.

[0071] In the above embodiments, the borehole 6 has different structures depending on the drilling mode. Specifically, when drilling on both sides, the borehole 6 is enlarged to a first preset diameter (e.g., 300 mm), and its borehole wall directly forms the coal-water gravity flow channel 8. The main body of the coal-water gravity flow channel 8 is used for the flow of the coal-water mixture. When drilling on one side, the borehole 6 maintains a smaller second preset diameter (i.e., the original diameter of the borehole 6 is sufficient). The coal-water gravity flow channel 8 is formed by the space enclosed by the flexible shield net 7 and the coal wall on the goaf side.

[0072] In addition, in this embodiment of the invention, starting from borehole 6 in the upper roadway, a flexible protective net 7 is laid into the coal mining face. The net consists of a double-layer diamond wire mesh, W-shaped steel strip support beams arranged every 1.5 meters, and two steel wire ropes with a diameter of 22mm. The width of the net exceeds the thickness of the coal seam by 1 meter to ensure complete coverage of the roof and floor. The upper end of the flexible protective net 7 is fixed to the roadway floor of the upper roadway with a bracing post, and the lower end can be directly and freely lowered to the upper side of the lower roadway for fixing. When the coal mining at this location is completed, the flexible protective net 7 sinks to the upper side of the lower roadway at the stop mining position under its own weight and the heavy pressure of the collapsed roof rock in the goaf.

[0073] In some embodiments, the drill rod has a hollow structure, is driven by the drilling rig, and can extend into the borehole 6. The high-pressure water gun is fixed to the top of the drill rod inside the borehole 6. Specifically, a tracked, fully hydraulic directional drilling rig is arranged in the lower roadway, near the opening of the borehole 6. The drilling rig has automatic drill rod unloading, rotation drive, and feed / pull-back functions. The drill rod is clamped and driven by the chuck of the drilling rig. The drill rod is a high-strength alloy steel pipe with an internal through hole for conveying high-pressure water. Its front end is rigidly sealed to the body of the high-pressure water gun through a high-pressure sealing joint. When coal mining needs to begin, the drilling rig first sends the drill rod and high-pressure water gun to the starting position on the bottom plate of the upper roadway. After the high-pressure water is connected, the drilling rig drives the entire drill rod to rotate slowly, causing the water gun to scan and break the coal body around the borehole 6. During the coal mining process, the drilling rig controls the drill rod to rotate and move downward step by step. Through the rigid connection and drive of the drilling rig, drill rod, and water gun, remote control of the coal breaking tool in the borehole is realized.

[0074] In some embodiments, the drill pipe integrates a high-pressure water flow channel and an optical cable channel for transmitting monitoring signals. The high-pressure water gun is equipped with a monitoring probe, which is connected to a remote monitoring system via an optical cable located within the optical cable channel. Specifically, in addition to the central through-hole serving as the main water flow channel, the drill pipe wall also pre-embeds a four-core shielded cable and two single-mode optical cables. The cable powers any possible miniature hydraulic valves or sensors in the water gun head, while the optical cables transmit data at high speed. Simultaneously, an explosion-proof and waterproof miniature high-definition camera and a methane sensor are encapsulated on the side of the high-pressure water gun. Their signal lines are connected to the cables inside the drill pipe via a special sealed plug at the front end. When the water gun operates in the borehole, the camera captures real-time footage of the coal face being impacted and broken by the water jet, and the methane sensor transmits the gas concentration data of the working environment to the monitoring host in the lower roadway in real time via the optical cable, and further uploads it to the ground dispatch center.

[0075] In some embodiments, the high-pressure water gun includes a gun body and at least one nozzle. When one nozzle is used, the high-pressure water gun has the function of breaking coal in a 180° range on one side. When two nozzles are used, the two nozzles are symmetrically arranged on the gun body so that the high-pressure water gun has the function of breaking coal in a 360° range on both sides.

[0076] In one specific embodiment, depending on the coal seam structure and hardness, the pressure of the high-pressure water gun is adjustable from 10-30 MPa, and the flow rate is 60-150 m³ / h. 3 / h is adjustable.

[0077] Specifically, in the above embodiments, when the roof of the coal seam being mined is relatively broken and prone to collapse, a single-sided drilling and mining mode is adopted. At this time, the high-pressure water gun is equipped with a single nozzle, which is installed biased towards the goaf side. When the drill rod drives the water gun to rotate, the high-pressure water jet only reciprocates to impact the coal wall within a 180° fan-shaped range towards the goaf. The broken coal blocks fall into the goaf side, and the space between the coal wall on this side and the lowered flexible protective net 7 is used as a coal chute (i.e., a coal-water gravity flow channel 8).

[0078] When the coal seam roof is hard and intact, a double-sided drilling mode is adopted to pursue higher output. At this time, a double-nozzle water gun is used, with the two nozzles arranged symmetrically at 180°. When the drill rod rotates, the high-pressure water jet can cover the entire 360° range around the borehole 6, while breaking the coal walls on both sides. At this time, the inner diameter of the borehole 6 after the hole is enlarged becomes an efficient coal-water gravity flow channel 8.

[0079] Therefore, the two arrangement methods of the spray guns provide two coal breaking modes that can flexibly adapt to different roof conditions. Single-sided drilling prioritizes safety, while double-sided drilling maximizes mining efficiency. This configurability allows the same system to cope with complex and varied geological conditions, enhancing the universality and economy of the technology.

[0080] Please refer to Figure 1 In some embodiments, the nozzle axis of the high-pressure water gun has a set deflection angle relative to the radial direction of the borehole 6. When one nozzle is used, the nozzle axis has a depression angle of 8° to 10° so that the coal-water mixture flows through the coal-water gravity flow channel 8 defined by the goaf side coal wall and the flexible shield net 7 to the lower roadway. When two nozzles are used, the nozzle axis has an elevation angle of 8° to 10° so that the coal-water mixture flows through the coal-water gravity flow channel 8 formed by the inner wall of the borehole 6 to the lower roadway.

[0081] Specifically, in the single-sided drilling mode, the central axis of the single nozzle of the high-pressure water gun is not horizontal, but is designed to be inclined downward, forming a depression angle of 8° to 10° with the radius of the cross-section of the borehole 6. In this way, while the water jet breaks up the coal body, it will generate a downward component force on the broken coal blocks, pushing them towards and guiding them to the coal chute space on the goaf side (i.e., the coal and water gravity flow channel 8 defined by the coal wall on the goaf side and the flexible shield net 7), effectively preventing the accumulation of coal blocks.

[0082] In the dual-side drilling mode, the central axis of the dual nozzles is designed to be inclined upwards, forming an elevation angle of 8° to 10° with the radial direction, making this position funnel-shaped. This serves two purposes: first, to make the jet impact point slightly higher than the center of borehole 6, which helps to increase the coal breaking height; more importantly, the upward impact force can cause some of the coal-water mixture to bounce after hitting the roof, and fall more fully into the central channel of borehole 6, avoiding coal slurry adhering to the borehole wall and causing blockage, and ensuring that coal and water can flow smoothly down the borehole 6.

[0083] By meticulously designing the nozzle pitch angle, the crushing and guiding functions of high-pressure water jets are cleverly combined, improving coal crushing efficiency. More importantly, it actively guides and optimizes the flow path of the coal-water mixture, avoiding production interruptions caused by blockage of the coal-water channel, and thus improving coal mining efficiency.

[0084] Please refer to Figure 1 The lower roadway has an inclination angle of 3° to 5°, so that the gravity-flow channel can transport the coal-water mixture to the transport uphill roadway 2 by gravity. Specifically, when the coal-water mixture flows out from the borehole 6 or the goaf, it first flows into the gravity-flow channel in the lower roadway. Under the gravity of the 3° slope, the coal slurry flows downstream automatically at a speed of about 0.5-1.0 m / s. After passing through the lower roadway, the coal slurry smoothly enters the transport uphill roadway 2, which greatly simplifies the production system, reduces equipment investment, energy consumption and maintenance costs, and improves the continuity and reliability of transportation.

[0085] Compared with traditional underground mechanized mining, this mining method can reduce the development of a main shaft and its hoisting equipment, reduce the main underground haulage roadway and its haulage equipment, and eliminate the need for haulage equipment for steeply inclined coal seam mining area 1, haulage equipment for the coal face roadway, and a complete set of equipment for the mechanized coal face. (This mining method adopts a pseudo-inclined incline and roadway gravity-flow slope design, which uses the weight of the coal-water mixture to achieve gravity-flow for transportation, solving the problems of roadway construction and coal and auxiliary transportation in steeply inclined coal seam mining area 1.)

[0086] Furthermore, when the mine has a large water inflow, the underground water can be fully utilized as a drilling and extraction water source, which can significantly reduce the investment in mine drainage projects, equipment and operating costs, resulting in a reduction of more than 30% in the total investment of the mine.

[0087] Because Borehole 6 fully utilizes high-pressure water and the weight of coal and water to achieve efficient operation of production processes such as coal mining, transportation, and hoisting, the production system is greatly simplified, the number of production personnel is reduced by more than 30%, the installed capacity of equipment is significantly reduced, and the costs of electricity, maintenance, and materials during the production process are significantly reduced, resulting in a 40-50% reduction in the production cost per ton of coal.

[0088] The No. 6 water mining system utilizes the water gun at the top of the drill rod inside the borehole operated by the drilling rig to automatically drop and transport coal, achieving unmanned operation at the drilling and mining face. Through the monitoring probe installed on the water gun head or the monitoring device suspended above the drilling and mining face, the working status, parameters, and coal breaking situation of the water gun can be directly monitored in real time, enabling remote monitoring and adjustment, that is, realizing remote visual unmanned coal mining.

[0089] In other words, the key point of this invention is to integrate the roadway, borehole 6, support, coal mining, and transportation into a single system. All high-risk mining operations are completed remotely via equipment within the borehole 6, while personnel operate the drilling rig and monitoring system only within the safe roadway 4. This fundamentally eliminates the direct threats to personnel from the roof and gas in traditional coal mining faces. Furthermore, the system's core does not rely on cumbersome equipment for stabilizing steep coal faces, thus making it highly adaptable to various coal seam dip angles, significantly improving mining efficiency and safety in steeply inclined coal seam mining areas 1, thus filling a gap in current ultra-steep coal seam mining. Its "ground remote control of underground drilling equipment operation" mode provides an important technical paradigm for the future comprehensive intelligent and unmanned mining of coal mines. The system has good scalability and can be easily integrated with more advanced geological exploration, robotics, big data analysis and other technologies. It also breaks down the complex mining of steeply inclined coal seams into a series of relatively simple, remotely operable steps, making the entire production process orderly and controllable. Its core advantage lies in completely freeing personnel from dangerous areas and making full use of the natural advantages of hydraulic mining and gravity transportation, which greatly improves the feasibility, efficiency and safety of mining steeply inclined coal seams.

[0090] In addition to the hydraulic coal mining method for drilling ultra-steep and steeply inclined coal seams disclosed in the above embodiments, the present invention also provides a method of using the above-mentioned hydraulic coal mining method for drilling ultra-steep and steeply inclined coal seams. For the structure of other parts of the method of use, please refer to the prior art, and it will not be described again in this article.

[0091] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0092] The present invention provides a detailed description of a method for hydraulic coal mining in ultra-steep and steeply inclined coal seams, as well as its application. Specific examples have been used to illustrate the principles and implementation methods of the invention. These examples are merely illustrative and are intended to aid in understanding the method and its core concepts. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A method for hydraulic coal mining with boreholes in ultra-steeply inclined coal seams, characterized in that, Includes the following steps: In the middle of the steeply inclined coal seam mining area (1), a reverse-type transport uphill roadway (2) and a return air uphill roadway (3) are arranged in a pseudo-inclination. The return air uphill roadway (3) is connected to the main return air roadway of the mining area. On both sides of the transport uphill roadway (2) and the return air uphill roadway (3), several roadways (4) connected to the transport uphill roadway (2) and the return air uphill roadway (3) are arranged according to the preset height using water excavation and water transport, so as to divide the steeply inclined coal seam mining area (1) into several mining sections (5). The first mining face is located at the uppermost part of the steeply inclined coal seam mining area (1), and mining is carried out from top to bottom in each mining section (5). The roadway at the bottom of the previous mining section (5) is used as the upper roadway return air roadway of the next mining section (5) to reduce the amount of roadway (4) excavation work. Drill holes (6) are constructed along the dipping direction of the coal seam at the boundary of the mining section (5). The drill holes (6) connect the roadway (4) at the top and bottom of the mining section (5) to form a full negative pressure ventilation system for the mining face. A flexible protective net (7) is laid on the bottom plate of the roadway (4) at the top of the mining section (5), and it is lowered synchronously with the coal mining operation to the upper side stop mining position of the roadway (4) at the bottom of the mining section (5); In the mining section (5), water mining boreholes (6) are constructed sequentially in the direction of the transport uphill roadway (2) to divide the mining section (5) into several coal mining blocks. The drill rod is inserted into the borehole (6). A drilling water gun is installed at the top of the drill rod, and its end is connected to a high-pressure water supply system. The drill rod is slowly swung by the drilling machine. The high-pressure water jet generated by the drilling water gun is used to hit and break the surrounding coal body radially along the borehole (6) and form a coal-water mixture to realize hydraulic coal mining. The coal-water mixture flows down the borehole (6) or the side coal wall of the goaf to the bottom of the mining section (5) via the roadway (4), and then flows by gravity from the roadway (4) to the transport uphill roadway (2), and then by gravity from the transport uphill roadway (2) to the main roadway centralized treatment station, where the coal-water slurry is pumped to the raw coal pool of the surface coal washing plant.

2. The hydraulic coal mining method for ultra-steeply inclined coal seams according to claim 1, characterized in that, The drill rod is inserted into the borehole (6). A drilling water gun is installed at the top of the drill rod, and its end is connected to a high-pressure water supply system. The drill rod is slowly oscillated by the drilling rig, and the high-pressure water jet generated by the drilling water gun is used to radially strike and break the surrounding coal body along the borehole (6) to form a coal-water mixture, so as to realize the following in hydraulic coal mining: The drilling rig drives the drill rod to move gradually toward the bottom of the coal block section so that the drilling water gun breaks the coal body around the borehole (6) in a step manner, and the height of a single step is 0.1 to 0.5 meters.

3. The hydraulic coal mining method for ultra-steeply inclined coal seams according to claim 2, characterized in that, The pressure of the drilling water gun is adjustable within the range of 10-30 MPa.

4. The hydraulic coal mining method for ultra-steeply inclined coal seams according to claim 3, characterized in that, The flexible protective net (7) is one of the following: double-layer diamond wire mesh, nylon, or plastic mesh.

5. The hydraulic coal mining method for ultra-steeply inclined coal seams according to claim 4, characterized in that, The coal-water mixture flows down the borehole (6) or the side coal wall of the goaf to the bottom of the mining section (5) of the roadway, and then flows by gravity through the transport uphill roadway (2) to the main roadway centralized treatment station. The coal-water slurry is then pumped by the coal slurry pump to the raw coal pool of the surface coal washing plant. The excess clean water after sedimentation in the surface raw coal pool and the centralized treatment station in the underground main roadway is returned to the suction pool of the drilling and production high-pressure pump to achieve water resource recycling.

6. The hydraulic mining method for ultra-steeply inclined coal seams according to claim 5, characterized in that, The roadway at the bottom of the previous mining section (5) is used as the upper roadway return airway of the next mining section (5) to reduce the amount of roadway excavation work (4); The mining roadway is equipped with a lower roadway for transporting coal-water mixture. The lower roadway is connected to the transport uphill roadway. The lower roadway has an inclination angle of 3° to 5° so that the mining roadway can transport coal-water mixture to the transport uphill roadway (2) by gravity.

7. The method for drilling hydraulic coal mining in ultra-steeply inclined coal seams according to any one of claims 1-6, characterized in that, The drill rod is inserted into the borehole (6). A drilling water gun is installed at the top of the drill rod, and its end is connected to a high-pressure water supply system. The drill rod is slowly oscillated by the drilling rig, and the high-pressure water jet generated by the drilling water gun is used to radially strike and break the surrounding coal body along the borehole (6) to form a coal-water mixture, so as to realize the following in hydraulic coal mining: Single-sided drilling and double-sided drilling can be selected based on the difficulty of roof management in the mining section (5).

8. The hydraulic coal mining method for ultra-steeply inclined coal seams according to claim 7, characterized in that, During single-sided drilling and mining, the drilling water gun only swings within a horizontal range of 180° to one side of the goaf area, and uses the space between the coal wall on the goaf side and the flexible shield net (7) as a coal and water self-flowing channel. During double-sided drilling and extraction, the drilling water gun swings within a 360° horizontal range, and by enlarging the diameter of the borehole (6), the borehole (6) is used as a coal-water flow channel.

9. The hydraulic coal mining method for ultra-steeply inclined coal seams according to claim 8, characterized in that, When single-sided drilling is used, the nozzle of the drilling water gun has a downward angle of 8° to 10° with the radial direction of the borehole (6). When double-sided drilling is used, the nozzle of the drilling water gun has an upward angle of 8° to 10° with the radial direction of the borehole (6).

10. The hydraulic mining method for ultra-steeply inclined coal seams according to claim 9, characterized in that, The drill pipe has an integrated optical fiber channel for transmitting monitoring signals. The drilling water gun is equipped with a monitoring probe, which is connected to a remote monitoring system via an optical fiber located in the optical fiber channel.

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