Staged drainage re-mining method for full-water-filling single-slope room-pillar re-mining area

Abstract

The invention provides a staged drainage re-mining method for a full-water-filling single-slope room and pillar type re-mining area, and belongs to the technical field of coal mining. The problems of complex drainage construction and long period of the existing monoclinic room-column type re-mining area are solved; comprising the following steps: collecting geological data of a full-water-filling monoclinic room-pillar type re-mining area, and preliminarily evaluating coal seam and water accumulation conditions of the re-mining area; the drainage level is divided according to the inclination length of a coal seam in a re-mining area in the collected geological data, then drainage stages are divided according to the drainage level, drainage facilities of all the stages are arranged, and drainage work is conducted in sequence according to division of the drainage stages; drainage drilling construction: carrying out drainage drilling and detection drilling construction at each drainage level; the drainage progress is monitored in real time through the detection drill hole; coal pillar stoping preparation work, wherein coal pillar stoping work is started step by step along with proceeding of all the drainage stages; the method is applied to residual coal re-mining.

Description

Technical Field

[0001] The present application relates to the technical field of coal mining, and in particular to a phased drainage and re-mining method for a fully water-filled monoslant room-and-pillar re-mining area. Background Art

[0002] As an important energy resource in my country, coal occupies a key position in the national economy. However, due to the limitations of mining technology in the past, many coal mines left behind a large amount of coal resources during the mining process, especially in the room-and-pillar mining method, the recovery rate of the remaining coal was low. These remaining coal resources have a high mining value and are the focus of the current coal resource recovery.

[0003] At present, with the continuous advancement of mining technology, mine re-mining technology has been significantly improved. The application of comprehensive mechanized coal mining, automation and intelligent equipment has greatly improved the recovery rate and mining efficiency of coal resources. However, when facing the problem of water accumulation in room-and-pillar re-mining areas, the existing technology still has some limitations. For example, the existing drainage methods usually require a large number of tunnel excavations, which are complex and time-consuming to construct. In addition, the drainage process lacks real-time monitoring methods, making it difficult to effectively control the discharge of accumulated water, resulting in the difficulty of quickly putting the re-mining process into production. Summary of the invention

[0004] In order to solve the problem of complex and long drainage construction period in mono-slope room-pillar re-mining areas, this application proposes a phased drainage and re-mining method for fully water-filled mono-slope room-pillar re-mining areas. It is a more efficient and flexible drainage solution that can shorten preparation time, improve the efficiency of coal pillar recovery, and ensure the safe and efficient completion of re-mining work.

[0005] The technical solution adopted in this application is: a staged drainage and re-mining method for a fully water-filled monoslant room-and-pillar re-mining area, comprising the following steps:

[0006] S1: Collect geological data of the fully water-filled monocline room-and-pillar mining area and conduct a preliminary assessment of the coal seams and water accumulation in the mining area;

[0007] S2: Divide the drainage and re-mining stages: Divide the drainage level according to the dip length of the coal seam in the re-mining area in the collected geological data, and then divide the drainage stages according to the drainage level, and arrange the detection drilling holes and drainage facilities and drainage drilling holes at each stage, and carry out the drainage work in sequence according to the division of drainage stages;

[0008] S3: Detection drilling and drainage drilling construction: Drainage drilling and detection drilling construction are carried out at each drainage level;

[0009] S4: Real-time monitoring of drainage progress through detection boreholes;

[0010] S5: Preparation for coal pillar mining: As each drainage stage progresses, coal pillar mining work is gradually started.

[0011] Furthermore, the geological data collected in step S1 include historical mining data of the coal seam, the structure of the coal seam and geological data near the mining area where the coal seam is located. The total volume of the re-mining area filled with water is estimated based on the area, thickness and recovery rate of the coal seam.

[0012] Furthermore, the specific division principle of the drainage level in step S2 is as follows:

[0013] For coal seams with a dip length of less than 1000m, they are divided into high drainage level, middle drainage level and low drainage level; the high drainage level is the highest point of the dip level of the coal seam, the middle drainage level is 1 / 2 of the dip level of the coal seam, and the low drainage level is the lowest point of the dip level of the coal seam;

[0014] For coal seams with a dip length greater than 1000m, they are divided into high drainage level, medium-high drainage level, middle drainage level, medium-low drainage level and low drainage level; the high drainage level is the highest point of the dip level of the coal seam, the middle drainage level is 1 / 2 of the dip level of the coal seam, the low drainage level is the lowest point of the dip level of the coal seam, the medium-high drainage level is 1 / 2 of the dip level of the coal seam between the high drainage level and the middle drainage level, and the medium-low drainage level is 1 / 2 of the dip level of the coal seam between the middle drainage level and the low drainage level;

[0015] The horizontal height of the coal seam dip refers to the height of a point along the dip direction of the coal seam relative to the reference plane with the deepest burial depth of the coal seam as the reference plane.

[0016] Furthermore, the principles for dividing drainage stages according to drainage levels are as follows:

[0017] For coal seams with a dip length of less than 1000m, the first drainage stage is between the high drainage level and the middle drainage level, and the second drainage stage is between the middle drainage level and the low drainage level;

[0018] For coal seams with a dip length greater than 1000m, the first drainage stage is between the high drainage level and the middle-high drainage level, the second drainage stage is between the middle-high drainage level and the middle drainage level, the third drainage stage is between the middle drainage level and the middle-low drainage level, and the fourth drainage stage is between the middle-low drainage level and the low drainage level.

[0019] Furthermore, the construction of drainage drilling holes in step S3 is carried out in sequence according to the divided drainage levels. First, the drilling construction and arrangement of drainage facilities for the high drainage level are carried out, and then the drilling construction and arrangement of drainage facilities for the medium-high drainage level, the medium drainage level, the medium-low drainage level, and the low drainage level are carried out in sequence to achieve staged drainage.

[0020] Furthermore, detection boreholes are evenly arranged in the dip direction of the coal seam, and water level sensors are provided in the detection boreholes to monitor water level changes.

[0021] Furthermore, the coal pillar recovery work in step S5 includes three steps: recovery preparation, recovery and drainage synchronization, and low-level drainage. The specific implementation process is as follows:

[0022] Preparation for mining: After high-level drainage is completed, the preparation for coal pillar recovery in the first stage of mining begins, that is, after the drainage work is completed in the first drainage stage, coal pillar mining begins from the high-level drainage level;

[0023] Synchronous mining and drainage: While the mining work in the previous stage is in progress, the next stage of draining the accumulated water continues, and at the same time, the coal pillar recovery work in the next stage of mining area is prepared;

[0024] Low-level drainage: When all the accumulated water in the entire re-mining area has been drained, drainage equipment and pipelines are arranged at the low-level drainage level to undertake the overall drainage work during the re-mining of the re-mining area. At the same time, the coal pillars in the re-mining area continue to be recovered, and finally the re-mining of the entire area is realized.

[0025] Furthermore, the drainage effect is calculated during the drainage process and after the drainage is completed. Based on the comparison between the estimated theoretical water level drop rate and the actual water level drop rate detected during the drainage process, it is determined whether the drainage process is normal, and adjustment measures are taken accordingly.

[0026] Furthermore, the drainage facilities include water pumps, drainage pipes, power distribution equipment and water tanks.

[0027] Furthermore, the water pump is matched with the drainage pipeline, and the drainage power of the water pump meets the mine's requirements for drainage capacity.

[0028] The beneficial effects of the present application compared to the prior art are as follows: the present application achieves efficient and safe drainage by draining water in stages and monitoring water accumulation in real time, shortens the preparation time of the re-mining area, and reduces the cost of tunnel excavation and construction. By rationally coordinating drainage and coal pillar recovery, the re-mining area can be put into production as soon as possible, greatly improving production efficiency and economic benefits. In addition, the solution of the present application is highly flexible and adaptable, and can be applied to different types of fully water-filled re-mining areas, with significant practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present application is further described below with reference to the accompanying drawings:

[0030] Figure 1 A schematic diagram of the division of coal seam drainage and re-mining stages provided in an embodiment of the present application;

[0031] Figure 2 A cross-sectional diagram of the distribution of drilling holes in the coal seam re-mining area provided in the embodiment of the present application;

[0032] Figure 3 A schematic diagram of a drainage and re-mining process for a mono-slope room-and-pillar re-mining area provided in an embodiment of the present application;

[0033] In the figure: 1-coal pillar; 2-high drainage level; 3-high drainage hole; 4-middle drainage hole; 5-low drainage hole; 6-existing tunnels underground; 7-middle drainage level; 8-low drainage level; 9-detection borehole; 10-first drainage stage; 11-second drainage stage; 12-high drainage hole section; 13-detection hole section; 14-middle drainage hole section; 15-low drainage hole section. DETAILED DESCRIPTION

[0034] like Figures 1 to 3 As shown, the present application provides a staged drainage and re-mining method for a fully water-filled mono-slope room-pillar re-mining area. By using the existing tunnels, the fully water-filled mono-slope room-pillar re-mining area is subjected to staged drainage, and then the mining work is carried out, which can improve the production efficiency of the mine. The main implementation steps are as follows:

[0035] S1: Collect existing geological data: Determine the basic conditions of the coal seams in the re-mining area based on the mining history of the coalfield and the geological data of nearby mines, and conduct a preliminary assessment of the coal seams and water accumulation in the re-mining area.

[0036] The geological data specifically include the following:

[0037] Basic information of coal seams: Collect historical coal seam mining data in the re-mining area, including information such as coal seam thickness, burial depth, and inclination.

[0038] · Assessment of water accumulation: Based on historical mining data, coal seam structure and geological data near the mining area, a preliminary assessment of the water accumulation in the re-mining area is made. If there is no complete geological data for the re-mining area, drilling engineering or geophysical exploration is required to supplement this data.

[0039] · Calculation of water accumulation volume: Estimate the total amount of water accumulation in the re-mining area. By calculating the area, thickness and recovery rate of the coal seam, the total volume of the re-mining area filled with water can be inferred. The formula is:

[0040] W = η × H × S;

[0041] Where: W is the total volume of water accumulation, η is the historical recovery rate; H is the thickness of the coal seam, in m; S is the area of ​​the coal seam, in m 2 .

[0042] S2: Divide the drainage and re-mining stages: According to the collected coal seams and water accumulation conditions, the re-mining area is divided into drainage stages, and the specific operation plan for each drainage stage is determined.

[0043] The specific implementation method is to first divide the drainage levels, divide the drainage stages according to the drainage levels, and arrange the drainage facilities for each stage.

[0044] The principle of drainage level division is: the drainage level is divided according to the dip length of the coal seam in the re-mining area:

[0045] For coal seams with a dip length of less than 1000m, they are divided into high drainage level, middle drainage level and low drainage level. The high drainage level is the highest dip level of the coal seam, the middle drainage level is 1 / 2 of the dip level of the coal seam, and the low drainage level is the lowest dip level of the coal seam;

[0046] For coal seams with a dip length greater than 1000m, they are divided into high drainage level, medium-high drainage level, middle drainage level, medium-low drainage level and low drainage level. The high drainage level is the highest dip level of the coal seam, the middle drainage level is 1 / 2 of the dip level of the coal seam, the low drainage level is the lowest dip level of the coal seam, the medium-high drainage level is 1 / 2 of the dip level of the coal seam between the high drainage level and the middle drainage level, and the medium-low drainage level is 1 / 2 of the dip level of the coal seam between the middle drainage level and the low drainage level;

[0047] The horizontal height of the coal seam dip refers to the height of a point along the dip direction of the coal seam relative to the reference plane with the deepest burial depth of the coal seam as the reference plane.

[0048] The function of the high drainage level is to arrange drainage facilities and pipelines at this stage, and to discharge the coal seam water between the high drainage level and the middle drainage level;

[0049] The function of the median drainage level is to arrange drainage facilities and pipelines at this stage, and to discharge the coal seam water between the median drainage level and the low drainage level;

[0050] The function of the low-level drainage level is to arrange drainage facilities and pipelines at this stage, and to undertake the daily drainage work of the re-mining area during the re-mining process after the existing accumulated water in the re-mining area is discharged.

[0051] The principle of drainage stage division is as follows: the coal seams are divided into different stages according to their height, and the accumulated water in the re-mining area is discharged from high to low in sequence according to the divided stages, gradually reducing the accumulated water level.

[0052] For coal seams with a dip length of less than 1000m, the first drainage stage is between the high drainage level and the middle drainage level, and the second drainage stage is between the middle drainage level and the low drainage level.

[0053] For coal seams with a dip length greater than 1000m, the first drainage stage is between the high drainage level and the middle-high drainage level, the second drainage stage is between the middle-high drainage level and the middle drainage level, the third drainage stage is between the middle drainage level and the middle-low drainage level, and the fourth drainage stage is between the middle-low drainage level and the low drainage level.

[0054] The re-mining area will carry out drainage work in sequence according to the division of drainage stages.

[0055] The principles for arranging drainage facilities are as follows:

[0056] According to the divided drainage levels, the drainage facilities are first arranged at the high drainage level.

[0057] The drainage facilities include the arrangement of water pumps, drainage pipes, power distribution equipment and water tanks, etc., to ensure that the construction of the drainage system complies with the requirements of safety regulations.

[0058] The drainage power of the water pump should meet the drainage capacity requirements of the corresponding mine.

[0059] The drainage pipeline should be matched with the water pump used.

[0060] The power distribution equipment described above should meet the working requirements of underground drainage equipment.

[0061] The water tank should meet the requirements of the mine for water tank capacity.

[0062] S3: Drainage drilling construction: Drainage drilling construction is carried out at each drainage level to prepare for subsequent drainage.

[0063] Detection boreholes are evenly arranged along the dip direction of the coal seam to prepare for subsequent monitoring work.

[0064] Drilling depth and diameter: Determine the depth and diameter of the borehole based on the depth of the coal seam and the water accumulation situation to ensure that the borehole can effectively drain the accumulated water while ensuring the stability and safety of the borehole.

[0065] Construction steps: During construction, first drill holes at the high drainage level for drainage. After completing the high drainage, drill holes at the middle drainage level and low drainage level in turn, and carry out drainage work in stages.

[0066] S4: Real-time monitoring of drainage progress: During the drainage process, the real-time situation of accumulated water is monitored through detection drilling to ensure the progress and safety of drainage.

[0067] The detection boreholes are evenly distributed in the coal seam dip direction to measure the water level at each stage. Through these boreholes, the effect of water discharge can be obtained in real time.

[0068] According to the data of the detection borehole, the change of the water level is judged. According to the monitoring results, the drainage progress is adjusted to prevent the problem of excessive drainage or incomplete drainage of water during the drainage process, and to prevent the emergence of new unknown water sources in the re-mining area during the drainage process, which will affect the drainage effect.

[0069] S5: Preparation for coal pillar recovery: As each drainage stage progresses, coal pillar recovery work is gradually started to ensure that the re-mining area can be put into production as soon as possible.

[0070] The coal pillar mining work is further divided into three steps: mining preparation, mining and drainage synchronization, and low-level drainage.

[0071] The mining preparation step refers to starting the coal pillar recovery preparation work in the first phase of the re-mining area after the high-level drainage is completed, that is, after the drainage work is completed in the first drainage stage, starting from the high-level drainage level, reasonably arrange equipment and personnel to ensure that the coal pillar recovery work is coordinated with the drainage work.

[0072] Synchronous mining and drainage: While the previous phase of mining is in progress, the next phase of draining the accumulated water is continued, and the coal pillar recovery work in the next phase of mining area is prepared at the same time. The simultaneous drainage and coal pillar recovery can shorten the total time of mining preparation.

[0073] Low-level drainage: After all the accumulated water in the entire re-mining area has been drained, drainage equipment and pipelines are arranged at the low-level drainage level to undertake the overall drainage work during the re-mining of the re-mining area. At the same time, the coal pillars in the re-mining area continue to be recovered, and finally the re-mining of the entire area is realized.

[0074] S6: Drainage effect calculation: Through water level monitoring and calculation during the drainage process, the drainage effect is calculated to ensure the quality and effect of the drainage work. The principle is as follows:

[0075] Calculate the water level drop rate: According to the total amount of water accumulation and drainage capacity in the re-mining area, calculate the theoretical water level drop rate. The formula is as follows:

[0076]

[0077] Where: V is the theoretical water level drop speed, in m / h; l is the length of the coal seam, in m; L is the equivalent total width of the historical mining tunnel, in m; P is the mine drainage capacity (determined by the water pump power), in m 3 / h; α is the average inclination angle of the monocline coal seam.

[0078] Among them, the equivalent total width L of the historical mining tunnel is calculated by the total volume of the water accumulation space W, the historical mining height h of the coal seam, and the single-side inclination length l of the coal seam, and the formula is as follows:

[0079]

[0080] According to the calculation results and the monitoring results, if the calculation results are basically consistent with the monitoring results, the drainage process is normal and the drainage effect is good. If the monitored water level drop rate is greater than the calculated result, it means that the accumulated water in the re-mining area has not been completely discharged and there are unconnected areas in the re-mining area. Therefore, under the condition of the same drainage capacity, the water level drops faster due to the reduction in the total drainage volume.

[0081] The method of the present application is further described below with reference to embodiments.

[0082] 1. Collect geological data

[0083] like Figure 1 As shown in the figure, for example, the No. 15 coal seam in an experimental mine has been mined in a room-and-pillar manner. The coal seam has a dip angle of 12° and is a mono-inclined coal seam. The average thickness of the coal seam is 6.5m, the historical mining height is 3m, the historical recovery rate is 17%, the coal seam is buried at a depth of 80 to 200m, and the length and width of the remaining coal pillars are both about 20m. The proven re-mining area is now completely filled with water. The historical mining area of ​​the No. 15 coal seam is 2 million m 2 , with a strike length of 2000m and a dip length of 900m.

[0084] According to the above data, the total amount of water accumulated in the re-mining area is estimated as follows:

[0085] In this estimation, since the amount of water accumulated in the re-mining area is much greater than the subsequent real-time water inflow in the re-mining area, the dynamic impact of the water inflow on the water accumulation in the re-mining area is not considered; since the re-mining area is completely filled with water, the water accumulation space capacity of the re-mining area can be used to estimate the total amount of water accumulated in the re-mining area. The water accumulation capacity of the re-mining area can be estimated based on the historical mining conditions of the coal seam. According to the existing data, the historical recovery rate of the No. 15 coal seam is 17%, and the water volume of the re-mining area accounts for 17% of the total volume of the coal seam. Therefore, the total amount of water accumulated in the re-mining area of ​​the No. 15 coal seam can be calculated:

[0086] W = η × H × S = 17% × 6.5 × 200 × 104 = 2.21 million m 3 ;

[0087] The total volume of water in the No. 15 coal seam is calculated to be 2.21 million m3 .

[0088] 2. Divide the drainage and re-mining stages

[0089] According to the collected geological data of coal seams in the re-mining area, the re-mining area is divided into stages. The dip length of coal seam No. 15 is less than 1000m, and it is divided into high drainage level 2, medium drainage level 7 and low drainage level 8.

[0090] The high drainage level 2 is the highest point of the coal seam dip level, the middle drainage level 7 is 1 / 2 of the coal seam dip level, and the low drainage level 8 is the lowest point of the coal seam dip level;

[0091] The function of the high drainage level 2 is to arrange drainage facilities and pipelines at this stage, and to discharge the coal seam water between the high drainage level 2 and the middle drainage level 7;

[0092] The function of the middle drainage level 7 is to arrange drainage facilities and pipelines at this stage, and to discharge the coal seam water between the middle drainage level 7 and the low drainage level 8;

[0093] The function of the low-level drainage level 8 is to arrange drainage facilities and pipelines at this stage, and to undertake the daily drainage work of the re-mining area during the re-mining process after the existing accumulated water in the re-mining area is discharged;

[0094] Layout of drainage facilities: Based on the divided drainage levels, the layout of drainage facilities is first carried out at the high drainage level 2.

[0095] The drainage facilities include water pumps, drainage pipelines, power distribution equipment and water tank arrangements.

[0096] The drainage capacity of the water pump should meet the drainage capacity requirements of the corresponding mine. The drainage capacity of the mine water pump is 1000m 3 / h, meeting the mine's requirements for water pump drainage capacity.

[0097] The underground drainage pipeline of this mine is matched with the water pump used, which can work normally and make the drainage work go smoothly.

[0098] The underground power distribution equipment in this mine meets the requirements of drainage equipment.

[0099] The mine water tank capacity is 10000m 3 , meeting the mine's requirements for water tank capacity.

[0100] The dip length of coal seam No. 15 in this mine is less than 1000m. The first drainage stage 10 is divided between the high drainage level 2 and the middle drainage level 7, and the second drainage stage 11 is divided between the middle drainage level 7 and the low drainage level 8. The re-mining area will carry out drainage work in sequence according to the division of drainage stages.

[0101] 3. Drainage drilling construction

[0102] like Figure 1 , drilling construction is carried out at each drainage level in the existing tunnel 6 underground, and detection boreholes 9 are uniformly constructed along the inclination direction to prepare for subsequent drainage and monitoring work:

[0103] Drilling arrangement: According to the layout of the coal seam, a number of drainage boreholes and detection boreholes 9 are arranged at each drainage level. The drainage boreholes are used to discharge accumulated water.

[0104] According to the layout of the coal seam, a plurality of detection boreholes 9 are evenly arranged along the dip direction of the coal seam, and the detection boreholes 9 are used to monitor the change of water level.

[0105] Drilling depth and diameter: Determine the depth and diameter of the borehole based on the depth of the coal seam and the water accumulation situation to ensure that the borehole can effectively drain the accumulated water while ensuring the stability and safety of the borehole.

[0106] Construction steps: During construction, first drain the water from the high-level drainage hole 3. After completing the high-level drainage, drill holes for the middle-level drainage level 7 and the low-level drainage level 8 in turn, and carry out the drainage work in stages.

[0107] 4. Real-time monitoring of drainage progress

[0108] During the drainage process, the real-time situation of the accumulated water is monitored by detecting the borehole 9 to ensure the progress and safety of the drainage.

[0109] like Figure 1 , the detection boreholes 9 are evenly distributed in the coal seam inclination direction, and are used to measure the water level at each stage. Through these boreholes, the effect of water discharge can be obtained in real time.

[0110] The change of the water level is determined based on the data from the detection borehole 9. The drainage progress is adjusted based on the monitoring results to prevent excessive drainage or incomplete drainage of water during the drainage process, and to prevent new unknown water sources from entering the re-mining area during the drainage process, thereby affecting the drainage effect.

[0111] 5. Preparation work for coal pillar mining

[0112] As each drainage stage progresses, coal pillar recovery work is gradually started to ensure that the re-mining area can be put into production as soon as possible.

[0113] The coal pillar mining work is further divided into three steps: mining preparation, mining and drainage synchronization, and low-level drainage.

[0114] The mining preparation step refers to starting the coal pillar recovery preparation work in the first phase of the re-mining area after the high-level drainage is completed, that is, after the drainage work is completed in the first drainage stage 10, starting from the high-level drainage level, reasonably arrange equipment and personnel to ensure that the coal pillar recovery work is coordinated with the drainage work.

[0115] Synchronous mining and drainage: While the previous phase of mining is in progress, the next phase of draining the accumulated water is continued, and the coal pillar recovery work in the next phase of mining area is prepared at the same time. Drainage and coal pillar recovery are carried out simultaneously, shortening the total time for mining preparation.

[0116] Low-level drainage: When all the accumulated water in the entire re-mining area has been drained, drainage equipment and pipelines are arranged at the low-level drainage level 8 to undertake the overall drainage work during the re-mining area. At the same time, the coal pillars in the re-mining area continue to be recovered, and finally the re-mining of the entire area is realized.

[0117] 6. Calculation of drainage effect

[0118] By monitoring and calculating the water level during the drainage process, the drainage effect is calculated to ensure the quality and effect of the drainage work.

[0119] The calculated equivalent total width of the historical mining tunnel is L = 2210000 / (3×900) = 818.52m.

[0120] Theoretical water level drop speed V = 1000 × cos (12 °) / (2000 × 818.52) = 5.975 × 10 -4 m / h.

[0121] The method of the present application utilizes existing underground tunnels for drilling construction, thereby reducing the workload of tunnel construction and the length of drilling holes, thereby improving economic benefits; the drainage of accumulated water in the re-mining area and the recovery of coal pillars are carried out in stages, thereby reducing the workload of tunnel excavation, shortening the preparation time of the room-and-pillar re-mining area, and enabling the re-mining area to be put into production as soon as possible; the remaining tunnels in the room-and-pillar re-mining area are utilized to connect the accumulated water in the re-mining area, thereby simplifying the drainage tunnel system and realizing efficient drainage of accumulated water in the re-mining area; the drainage and coal pillar recovery work are carried out in a coordinated manner, thereby shortening the preparation period of the re-mining area and improving production efficiency.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A staged drainage and re-mining method for a fully water-filled monocline room-and-pillar re-mining area, characterized by: The following steps are involved: S1: Collect geological data of the fully water-filled monocline room-and-pillar mining area and conduct a preliminary assessment of the coal seams and water accumulation in the mining area; S2: Divide the drainage and re-mining stages: Divide the drainage level according to the dip length of the coal seam in the re-mining area in the collected geological data, and then divide the drainage stages according to the drainage level, and arrange the detection drilling holes and drainage facilities and drainage drilling holes at each stage, and carry out the drainage work in sequence according to the division of drainage stages; S3: Detection drilling and drainage drilling construction: Drainage drilling and detection drilling construction are carried out at each drainage level; S4: Real-time monitoring of drainage progress through detection boreholes; S5: Preparation for coal pillar mining: As each drainage stage progresses, coal pillar mining work is gradually started.

2. A phased drainage and re-mining method for a fully water-filled monocline room-and-pillar re-mining area according to claim 1, characterized in that: The geological data collected in step S1 include historical mining data of the coal seam, the structure of the coal seam and geological data near the mining area where the coal seam is located. The total volume of the re-mining area filled with water is estimated based on the area, thickness and recovery rate of the coal seam.

3. A phased drainage and re-mining method for a fully water-filled monocline room-and-pillar re-mining area according to claim 1, characterized in that: The specific division principle of the drainage level in step S2 is as follows: For coal seams with a dip length of less than 1000m, they are divided into high drainage level, middle drainage level and low drainage level; the high drainage level is the highest point of the dip level of the coal seam, the middle drainage level is 1 / 2 of the dip level of the coal seam, and the low drainage level is the lowest point of the dip level of the coal seam; For coal seams with a dip length greater than 1000m, they are divided into high drainage level, medium-high drainage level, middle drainage level, medium-low drainage level and low drainage level; the high drainage level is the highest point of the dip level of the coal seam, the middle drainage level is 1 / 2 of the dip level of the coal seam, the low drainage level is the lowest point of the dip level of the coal seam, the medium-high drainage level is 1 / 2 of the dip level of the coal seam between the high drainage level and the middle drainage level, and the medium-low drainage level is 1 / 2 of the dip level of the coal seam between the middle drainage level and the low drainage level; The horizontal height of the coal seam dip refers to the height of a point along the dip direction of the coal seam relative to the reference plane with the deepest burial depth of the coal seam as the reference plane.

4. A phased drainage and re-mining method for a fully water-filled monocline room-and-pillar re-mining area according to claim 3, characterized in that: The principles for dividing drainage stages according to drainage levels are as follows: For coal seams with a dip length of less than 1000m, the first drainage stage is between the high drainage level and the middle drainage level, and the second drainage stage is between the middle drainage level and the low drainage level; For coal seams with a dip length greater than 1000m, the first drainage stage is between the high drainage level and the middle-high drainage level, the second drainage stage is between the middle-high drainage level and the middle drainage level, the third drainage stage is between the middle drainage level and the middle-low drainage level, and the fourth drainage stage is between the middle-low drainage level and the low drainage level.

5. A phased drainage and re-mining method for a fully water-filled monocline room-and-pillar re-mining area according to claim 4, characterized in that: The construction of drainage drilling holes in step S3 is carried out in sequence according to the divided drainage levels. First, the drilling construction and arrangement of drainage facilities are carried out for the high drainage level, and then the drilling construction and arrangement of drainage facilities are carried out for the medium-high drainage level, the medium drainage level, the medium-low drainage level, and the low drainage level in sequence to achieve staged drainage.

6. A phased drainage and re-mining method for a fully water-filled monocline room-and-pillar re-mining area according to claim 1, characterized in that: Detection boreholes are evenly arranged in the dip direction of the coal seam, and water level sensors are installed in the detection boreholes to monitor water level changes.

7. A phased drainage and re-mining method for a fully water-filled monocline room-and-pillar re-mining area according to claim 4, characterized in that: The coal pillar recovery work in step S5 includes three steps: recovery preparation, recovery and drainage synchronization, and low-level drainage. The specific implementation process is as follows: Preparation for mining: After high-level drainage is completed, the preparation for coal pillar recovery in the first stage of mining begins, that is, after the drainage work is completed in the first drainage stage, coal pillar mining begins from the high-level drainage level; Synchronous mining and drainage: While the mining work in the previous stage is in progress, the next stage of draining the accumulated water continues, and at the same time, the coal pillar recovery work in the next stage of mining area is prepared; Low-level drainage: When all the accumulated water in the entire re-mining area has been drained, drainage equipment and pipelines are arranged at the low-level drainage level to undertake the overall drainage work during the re-mining of the re-mining area. At the same time, the coal pillars in the re-mining area continue to be recovered, and finally the re-mining of the entire area is realized.

8. A phased drainage and re-mining method for a fully water-filled monocline room-and-pillar re-mining area according to any one of claims 1 to 7, characterized in that: The drainage effect is calculated during the drainage process and after the drainage is completed. Based on the comparison between the estimated theoretical water level drop rate and the actual water level drop rate detected during the drainage process, it is judged whether the drainage process is normal and adjustment measures are taken accordingly.

9. A phased drainage and re-mining method for a fully water-filled monocline room-and-pillar re-mining area according to claim 8, characterized in that: Drainage facilities include water pumps, drainage pipes, power distribution equipment and water tanks.

10. A phased drainage and re-mining method for a fully water-filled monocline room-and-pillar re-mining area according to claim 9, characterized in that: The water pump is matched with the drainage pipeline, and the drainage power of the water pump meets the mine's requirements for drainage capacity.

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