A method for hydraulic mining of near-vertical medium-thick coal seams

Abstract

The application discloses a kind of near vertical medium-thick coal seam hydraulic mining method, applied to coal mining engineering technical field, comprising: by connecting lane, each mining section is divided into several coal bodies, the upper part of coal body is arranged air return crossheading, lower part is arranged transport crossheading, and the height direction is interval arranged several hydraulic mining chambers in each coal body two sides;Hydraulic coal mining machine is arranged in chamber, to implement hydraulic coal breaking to the front coal body of same side chamber in order from bottom to top;When the highest chamber of same side is completed coal breaking, coal mining machine is transferred to the highest chamber of opposite side, to implement reverse complementary mining to residual coal body after coal breaking in chamber in order from top to bottom;When the lowest chamber of opposite side is completed reverse complementary mining, the present coal body mining is finished, and next coal body is entered, realizes subsection continuous connection.This application does not need complete set of support to continuously advance, realizes coal water continuous external transport, can realize efficient coal mining under the occurrence condition of near vertical medium-thick coal seam, and gives consideration to coal recovery rate and surrounding rock stability.

Description

Technical Field

[0001] This invention relates to the field of coal mining engineering technology, and more specifically to a method for hydraulic mining of near-vertical medium-thick coal seams. Background Technology

[0002] In the coal industry, coal seams with a dip angle of 45° to 90° are generally referred to as steeply dipping coal seams. Many steeply dipping coal seams are distributed in western regions of my country, such as Gansu, Xinjiang, and Ningxia. In some Xinjiang mining areas, the dip angle can reach 80° to 85°, exhibiting a near-vertical occurrence. Due to their large dip angles and limited mining space, the migration characteristics of these coal and rock masses under gravity and mining operations differ significantly from those of gently dipping coal seams.

[0003] For near-vertical extra-thick coal seams with a thickness greater than 20 m, coal resources can be recovered through horizontal segmented fully mechanized longwall mining. However, for near-vertical coal seams with a thickness less than 10 m, the length of the horizontal segmented fully mechanized longwall face is relatively short, and it is difficult to arrange hydraulic supports, coal mining machines, and transportation equipment in a complete set according to the conventional fully mechanized longwall face configuration, which limits the applicability of this technology.

[0004] Existing near-vertical medium-thick coal seam mining schemes mainly include milling machine mining and roadway top coal caving mining. Milling machine mining has problems such as difficulty in support advancement, the need for manual assistance in coal breaking, complex working face layout, and insufficient production capacity release; while roadway top coal caving mining has problems with incomplete ventilation, coal transportation, and mining follow-up systems, making it difficult to form a continuously implementable engineering process.

[0005] Hydraulic coal mining utilizes high-pressure water jets to cut and erode the coal seam. The crushed coal can then be transported along low-level channels to form a coal-water slurry. It features equipment that can be arranged within chambers and is highly adaptable to short working faces. However, if conventional hydraulic coal mining equipment is directly applied to near-vertical coal seams, several issues still need to be addressed, including the arrangement of upper and lower roadways, the organization of airflow and coal-water flow, the connection of multiple chambers, and the recovery of residual coal after unidirectional jetting.

[0006] Therefore, how to provide a complete system that can continuously advance without the need for a complete set of supports, achieve efficient mining under the special coal seam occurrence conditions of near-vertical medium-thick coal seams, enable continuous coal and water transportation, adapt to short working face mining conditions, and facilitate the control of mining boundaries and surrounding rock stability is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention provides a method for hydraulic mining of near-vertical medium-thick coal seams. This method uses a return airway, a transport roadway, and connecting roadways as the basic development system. Hydraulic mining chambers are set up on both sides of the coal seam, and hydraulic coal mining machines are used to mine the coal in stages and sequentially, with timely reverse mining as needed. A coal-water transport channel is provided in the transport roadway to allow the coal-water slurry formed by hydraulic coal breaking to be continuously collected and transported. The connecting roadway simultaneously serves the functions of ventilation, equipment transfer, and work continuity.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for hydraulic mining of near-vertical, medium-thick coal seams, comprising: Step 1: Divide the mining into sections. Each mining section is divided into several coal seams by connecting roadways. The upper part of the coal seam is arranged with a return air roadway, and the lower part is arranged with a transport roadway. The return air roadway and the transport roadway are connected by connecting roadways. Several hydraulic mining chambers are set at intervals along the height direction on both sides of each coal seam. Step 2: Select the lowest hydraulic mining chamber on one side of the coal seam as the first mining chamber, place the hydraulic coal mining machine in the hydraulic mining chamber, and hydraulically break the coal seam in front of the chamber on the same side in a bottom-up order. The broken coal seam is mixed with water to form a coal-water slurry, which flows into the transport roadway through the chamber and connecting roadway. Step 3: After hydraulic coal breaking is completed in the highest chamber on the same side, the hydraulic coal mining machine is moved to the highest chamber on the opposite side. The remaining coal after hydraulic coal breaking is carried out in reverse mining in a top-down order, so that the jet breaking zone formed by the mining and the mining void formed by hydraulic coal breaking are connected. Step 4: After the reverse mining of the lowest chamber on the opposite side is completed, the mining of the current coal body ends. Then, the next coal body is mined according to the method of Step 2-3 to achieve segmented continuous mining.

[0009] Optionally, in step 1, the mining sections are divided along the coal seam strike or the mine design direction.

[0010] Optionally, in step 1, an enamel chute is provided in the transport roadway to receive and transport the coal-water slurry formed by hydraulic coal breaking.

[0011] Optionally, in step 1, the spacing between the hydraulic mining chambers is set to allow adjacent hydraulic jet crushing zones to connect with each other, while retaining temporary coal bodies that meet the requirements of operational safety and surrounding rock stability.

[0012] Optionally, step 4, after the mining of the coal seam is completed, also includes: draining the coal seam and checking its stability, and sealing off any unused workspace.

[0013] Optionally, during the mining process, fresh air enters the working chamber through the transport roadway and connecting roadway, while stale air is discharged through the upper return air roadway. The specific airflow direction is adjusted automatically according to the mine ventilation system to ensure that the working chamber has an independent and continuous air intake and return path.

[0014] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a method for hydraulic mining of near-vertical medium-thick coal seams, achieving the following beneficial effects: (1) Forming a complete mining system: By setting up a return air roadway at the top of the coal seam and a transport roadway at the bottom, and connecting the upper and lower roadways and each hydraulic mining chamber with a connecting roadway, ventilation, equipment transfer, coal and water collection and mining continuity are clearly defined, solving the problem of incomplete roadway top coal caving scheme system and difficulty in implementation.

[0015] (2) Reduce the support propulsion process of the working face: The hydraulic coal mining machine is arranged in the mining chamber to carry out jet crushing of the coal body in front. The working position changes with the chamber. It does not need to continuously push the complete set of supports like the working face of the milling machine, thus simplifying the working face layout and reducing the reliance on manual coal breaking and support moving.

[0016] (3) Improve the efficiency of coal body crushing and mining continuity: start mining from the lowest mining chamber on one side from bottom to top, and then transfer to the highest mining chamber on the opposite side of the adjacent mining coal body to supplement mining from top to bottom. Use bidirectional jets to cover the residual coal body in different directions and reduce the difficult crushing zone formed by unidirectional mining.

[0017] (4) Realize continuous coal-water collection and external transportation: The coal-water slurry formed by hydraulic coal breaking enters the enamel chute in the transport roadway under the action of gravity and is discharged along the transport roadway; This transportation method is coordinated with the layout of the lower transport roadway, which can avoid the arrangement of large coal transfer equipment in the short working face.

[0018] (5) Adaptable to the conditions of short working faces in near vertical medium-thick coal seams: The coal body is divided into sections by connecting roadways, and each section is partially mined through several mining chambers. The mining unit is no longer limited by the working face length required by the entire set of horizontal segmented fully mechanized mining equipment.

[0019] (6) Facilitates control of mining boundaries and operation sequence: The location of the chamber, the direction of the jet and the sequence of mining up and down jointly limit the spatial range of each hydraulic coal breaking operation. The spacing between chambers and the jet parameters can be adjusted according to the state of coal body crushing, which is conducive to balancing recovery rate and surrounding rock stability. Attached Figure Description

[0020] 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.

[0021] Figure 1 This is a schematic diagram of the method flow provided by the present invention.

[0022] Figure 2 This is a schematic diagram of the mining system layout provided by the present invention.

[0023] Figure 3 This is a schematic diagram of the structure provided by the present invention, which uses the lowest hydraulic mining chamber on one side of the coal seam as the first mining chamber and performs hydraulic coal breaking on the coal seam in front of the chamber.

[0024] Figure 4 This is a schematic diagram of the structure provided by the present invention, which describes the hydraulic breaking of coal in front of the first mining chamber when transferring the coal to the next hydraulic mining chamber.

[0025] Figure 5 This is a schematic diagram of the structure provided by the present invention, which describes the hydraulic breaking of coal in front of the same-side chamber in a bottom-up sequence.

[0026] Figure 6 This is a schematic diagram of the structure provided by the present invention, which involves reverse mining of the residual coal body after hydraulic coal breaking, starting from the highest chamber on the opposite side.

[0027] Figure 7 This is a schematic diagram of the structure provided by the present invention, which involves transferring the coal from the highest chamber on the opposite side to the next hydraulic mining chamber and performing reverse mining on the residual coal body after hydraulic coal breaking.

[0028] Figure 8 This is a schematic diagram of the structure provided by the present invention for reverse mining of the residual coal body after hydraulic coal breaking in a top-down, chamber-by-chamber sequence.

[0029] Figure 9 This is a schematic diagram of the structure of the current coal seam after mining has ended and a goaf has been formed, provided by the present invention.

[0030] In the diagram, 1-coal body, 2-goaf, 3-return airway, 4-transport roadway, 5-connecting roadway, 6-hydraulic mining chamber, 7-enamel chute, 8-hydraulic mining machine, 9-goaf, 10-high-pressure water jet. Detailed Implementation

[0031] 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.

[0032] Example 1: Embodiment 1 of this invention discloses a method for hydraulic mining of near-vertical medium-thick coal seams, such as... Figure 1 As shown, it includes: Step 1: As Figure 2 As shown, the mining is divided into sections, and each mining section is divided into several coal bodies 1 (the mined area forms a goaf 2) through the connecting roadway 5. The upper part of the coal body 1 is arranged with a return air roadway 3, and the lower part is arranged with a transport roadway 4. The return air roadway 3 and the transport roadway 4 are connected by the connecting roadway 5, and several hydraulic mining chambers 6 are arranged at intervals along the height direction on both sides of each coal body 1.

[0033] Mining sections are divided along the strike of the coal seam or the design direction of the mine.

[0034] The transport roadway 4 is equipped with an enamel chute 7, which is used to receive and transport the coal-water slurry formed by hydraulic coal breaking.

[0035] The hydraulic coal mining machine 8 can be moved between the various hydraulic mining chambers 6.

[0036] The spacing of the hydraulic mining chamber 6 is set to allow adjacent hydraulic jet crushing zones to connect with each other, while retaining temporary coal bodies that meet the requirements of operational safety and surrounding rock stability.

[0037] After completing the construction of return air roadway 3, transport roadway 4, connecting roadway 5, and hydraulic mining chamber 6, check the connection between the upper and lower roadways, ventilation and drainage conditions, and lay enamel chutes 7 in transport roadway 4.

[0038] Step 2: As Figure 3 As shown, the lowest hydraulic mining chamber 6 on one side of the coal seam 1 is selected as the first mining chamber, and the hydraulic coal mining machine 8 is arranged inside the hydraulic mining chamber 6, as follows: Figure 4 He Ru Figure 5 The coal body in front of the chamber on the same side is hydraulically broken up in the order shown from bottom to top (forming a mining void 9). The broken coal body is mixed with water to form a coal-water slurry, which flows into the transport roadway 4 through the chamber and connecting roadway 5.

[0039] The hydraulic coal mining machine 8 is positioned inside the hydraulic mining chamber 6 to hydraulically break up the coal seam in front of the chamber. The specific process is as follows: Orient the nozzle of the hydraulic coal mining machine 8 toward the coal body 1, start the hydraulic coal mining machine 8, and use high-pressure water jet 10 to cut, erode and crush the coal body in front of the chamber. The crushed coal body mixes with water to form a coal-water slurry, which flows into the enamel chute 7 in the transport roadway 4 through the chamber and connecting roadway 5.

[0040] Step 3: As Figure 6 As shown, after hydraulic coal breaking is completed in the highest chamber on the same side, the hydraulic coal mining machine 8 is moved to the highest chamber on the opposite side, so as... Figure 7 He Ru Figure 8 The residual coal body after hydraulic coal breaking is reversed and supplemented in a top-down sequence, so that the jet breaking zone formed by supplementary mining is connected with the mining void 9 formed by hydraulic coal breaking.

[0041] Step 4: As Figure 9 As shown, after the reverse mining of the lowest chamber on the opposite side is completed, the mining of the current coal body 1 ends, and the next coal body 1 is entered according to the method of steps 2-3 to achieve segmented continuous mining.

[0042] After the mining of coal seam 1 is completed, the following steps are also taken: draining coal seam 1 and checking its stability, and sealing off any unused workspace.

[0043] During the mining process, fresh air enters the working chamber through the transport roadway 4 and the connecting roadway 5, while polluted air is discharged through the upper return air roadway 3. The specific airflow direction is adjusted automatically according to the mine ventilation system to ensure that the working chamber has an independent and continuous air intake and return path.

[0044] The coal-water slurry flows into the enamel chute 7 by means of the elevation difference and is transported out along the transport roadway 4. It can then be connected to the mine's existing coal-water separation and drainage reuse system.

[0045] Water pressure, flow rate, nozzle diameter, jet distance, chamber spacing, and single-cycle time should be determined based on the coal body's firmness, joints and fissures, water content, roof and floor stability, and effective jet breaking radius. The control principles are: the breaking ranges of adjacent chambers can overlap; the jet should not exceed the designed mining boundary; and the coal-water slurry discharge capacity should match the coal breaking speed.

[0046] This invention is applicable to near-vertical medium-thick coal seams with large dip angles, where conventional horizontal segmented fully mechanized longwall mining equipment is difficult to deploy due to insufficient working face length. The upper limit of applicable thickness applies to coal seam conditions where horizontal segmented fully mechanized longwall mining is no longer technically suitable. The dip angle, lower limit of thickness, and mineable boundary should be determined based on mine geological data and the coal seam classification standards adopted by the enterprise.

[0047] Example 2: Embodiment 2 of the present invention discloses the specific application of a near-vertical medium-thick coal seam hydraulic mining method in different coal seams, as follows: (1) Mining of near-vertical medium-thick coal seams: The system includes a return air roadway 3, a transport roadway 4, a connecting roadway 5, and hydraulic mining chambers 6 on both sides. An enamel-lined chute 7 is laid in the transport roadway 4. The hydraulic coal mining machine 8 first enters the lowest chamber on the left side of the coal seam 1 and mines chamber by chamber from bottom to top; then it moves to the highest chamber on the opposite side and mines in reverse order from top to bottom. The broken coal seam forms a coal-water slurry, which flows into the enamel-lined chute 7 and is transported out until a goaf 2 is formed.

[0048] (2) Mining of steeply inclined medium-thick coal seams: When the coal seam has a large dip angle, the mining of the return airway 3, transport roadway 4, and connecting roadway 5 in the development system can utilize the coal seam dip angle to transport the broken coal body, eliminating the need to arrange the development system in an inclined state and reducing the difficulty of development. The transport direction and equipment entry direction are based on the shaft layout. The optimal lowest chamber is selected as the first mining chamber, and mining is completed from bottom to top in the first direction. Then, mining is carried out from top to bottom from the highest chamber on the opposite side. Except for the system layout dip angle, the roadway composition, water-coal slurry collection method, and two-way overburden relationship are the same as those for "near-vertical medium-thick coal seam mining".

[0049] (3) Mining of hard, medium-thick coal seams: The density of the chambers is adjusted according to the coal body's fracturing conditions. In coal bodies with well-developed joints and fractures and a large effective fracturing range for the jet, the spacing between adjacent hydraulic mining chambers 6 is appropriately increased. In areas where the coal body is relatively intact, has high firmness, or exhibits significant jet attenuation, the spacing between chambers is reduced, or layered and angled jet circulation is added within the same chamber. Regardless of the arrangement, adjacent fracturing zones are kept connected, and a bottom-up mining sequence is implemented on one side and top-down on the opposite side.

[0050] Comparative Example 1: Comparative Example 1 of this invention discloses a prior art coal milling machine mining process, as follows: The working face of a coal milling machine requires the arrangement and continuous advancement of supports. After the coal mining is completed, problems often arise where the supports cannot advance autonomously and require manual coal breaking assistance. Under the condition of a short working face in a near-vertical medium-thick coal seam, the equipment arrangement and advancement process is complex. However, the hydraulic mining method for near-vertical medium-thick coal seams provided by this invention arranges the hydraulic coal mining machine 8 in the chamber and completes the continuity by transferring it between chambers, eliminating the need for the entire set of supports to continuously advance along the working face.

[0051] Comparative Example 2: Comparative Example 2 of this invention discloses a prior art roadway top coal caving mining process, as follows: Existing top coal caving schemes lack a complete ventilation, coal transportation, and follow-up system to support the mining process. This invention provides a near-vertical hydraulic mining method for medium-thick coal seams, which, through the combination of an upper return airway 3, a lower transport roadway 4, a connecting roadway 5, a hydraulic mining chamber 6, and an enamel chute 7, clearly defines the flow paths of air, equipment, and coal and water.

[0052] Comparative Example 3: Comparative Example 3 of this invention discloses a method of unidirectional chamber-by-chamber hydraulic extraction, as follows: If mining proceeds chamber by chamber from bottom to top from only one side, the hydraulic jet may leave residual coal away from the jet direction or between adjacent fractured zones due to the influence of the coal body structure and existing voids. This invention provides a near-vertical, medium-thick coal seam hydraulic mining method that adds a reverse mining step from top to bottom in the highest chamber on the opposite side, allowing the fractured zones in both directions to overlap.

[0053] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0054] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for hydraulic mining of near-vertical medium-thick coal seams, characterized in that, include: Step 1: Divide the mining into sections. Each mining section is divided into several coal seams by connecting roadways. The upper part of each coal seam is arranged with a return air roadway, and the lower part is arranged with a transport roadway. The return air roadway and the transport roadway are connected by the connecting roadway. Several hydraulic mining chambers are arranged at intervals along the height direction on both sides of each coal seam. Step 2: Select the lowest hydraulic mining chamber on one side of the coal seam as the first mining chamber, place the hydraulic coal mining machine in the hydraulic mining chamber, and hydraulically break the coal seam in front of the chamber on the same side in a bottom-up order. The broken coal seam is mixed with water to form a coal-water slurry, which flows into the transport roadway through the chamber and connecting roadway. Step 3: After the hydraulic coal breaking is completed in the highest chamber on the same side, the hydraulic coal mining machine is transferred to the highest chamber on the opposite side. The residual coal body after hydraulic coal breaking is carried out in reverse mining in a top-down order, so that the jet crushing zone formed by the mining and the mining void formed by hydraulic coal breaking are connected to each other. Step 4: After the reverse mining is completed in the lowest chamber on the opposite side, the mining of the current coal body ends, and the next coal body is entered according to the method of Step 2-Step 3 to achieve segmented continuous mining.

2. The method for hydraulic mining of near-vertical medium-thick coal seams according to claim 1, characterized in that, In step 1, the mining sections are divided along the coal seam strike or the mine design direction.

3. The method for hydraulic mining of near-vertical medium-thick coal seams according to claim 1, characterized in that, In step 1, an enamel chute is provided in the transport roadway to receive and transport the coal-water slurry formed by hydraulic coal breaking.

4. The method for hydraulic mining of near-vertical medium-thick coal seams according to claim 1, characterized in that, In step 1, the spacing between the hydraulic mining chambers is set to allow adjacent hydraulic jet crushing zones to connect with each other, while retaining temporary coal bodies that meet the requirements of operational safety and surrounding rock stability.

5. The method for hydraulic mining of near-vertical medium-thick coal seams according to claim 1, characterized in that, Step 4, after the mining of the coal body is completed, also includes: draining the coal body and checking its stability, and sealing off the unused workspace.

6. The method for hydraulic mining of near-vertical medium-thick coal seams according to claim 1, characterized in that, During the mining process, fresh air enters the working chamber through the transport roadway and connecting roadway, while polluted air is discharged through the upper return air roadway. The specific airflow direction is automatically adjusted according to the mine ventilation system to ensure that the working chamber has an independent and continuous air intake and return path.

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