A design method for controlling the ecological water level threshold under repeated mining in coal mines

Abstract

The present invention proposes a design method for controlling the ecological water level threshold in repeated mining of coal mines. First, collect the influencing factors of the ecological water level threshold, such as the water content of the surface soil, soil salt content, vegetation coverage, types and grades of vegetation protection in the designed area of the mine K <subgt; i < / subgt>, and determine the control value of the ecological water level threshold H <subgt; c < / subgt>; Use laboratory test methods to study the compaction characteristics of filling materials and the physical and mechanical parameters of coal and rock masses under the geological conditions of the mine; Use numerical simulation methods to study the filling rate in the repeated mining design area φ <subgt; i < / subgt> The height of the ecological water level drop under changing conditions H <subgt; i < / subgt>, and respectively fit and analyze to obtain the relationship expressions between the filling rate φ <subgt; i < / subgt> and the height of the ecological water level drop H <subgt; i < / subgt>; Finally, based on the actual engineering parameters and requirements of filling coal mining, combined with the critical filling rate for controlling the ecological water level threshold φ <subgt; ic,

Description

Technical Field

[0001] The present invention relates to the field of mine ecological water level and environmental protection, and particularly to a design method for controlling the ecological water level threshold in repeated mining of coal mines. Background Art

[0002] The ecological water level threshold of groundwater generally refers to the critical demand value that can meet the absorption and utilization of groundwater by various terrestrial plants such as arbors, shrubs, and herbs, and can avoid soil salinization or land desertification. During the repeated mining process in coal mines, the roof subsides and the groundwater level drops, resulting in soil desertification. Backfill mining is a green mining method that uses solid waste products such as coal gangue, fly ash, aeolian sand, and loess to fill the goaf, which can effectively control the movement of the top rock. Summary of the Invention

[0003] The purpose of the present invention is to provide a design method for controlling the ecological water level threshold in repeated mining of coal mines.

[0004] A design method for controlling the ecological water level threshold in repeated mining of coal mines includes:

[0005] Step 1: Collect the ecological water level threshold influence index K of the mine design area i , to determine the ecological water level threshold control value H c ;

[0006] Step 2: Obtain the compaction characteristics of the filling material and the key physical and mechanical parameters of the coal and rock mass under the mine geological conditions by using laboratory test methods:

[0007] Step 3: Numerical simulation:

[0008] (31) Based on the compaction characteristics of the filling material and the key physical and mechanical parameters of the coal and rock mass obtained in Step 2, construct a three-dimensional numerical analysis model;

[0009] (32) Taking different coal seams as the research objects, for each coal seam, the filling rate is used as the input parameter of the three-dimensional numerical analysis model, and the ecological water level drop height H under the condition of changing the filling rate is obtained through the three-dimensional numerical analysis model; i ;

[0010] (33) Statistically analyze the ecological water level drop height H corresponding to different filling rates of each coal seam Filling rate ; i ;

[0011] (34) Based on the statistical results, obtain the filling rate of each coal seam and the ecological water level drop height H iCurve relationship diagram between them, fitting expression corresponding to the curve relationship diagram;

[0012] Step 4. Obtain the final filling rate corresponding to each coal seam Specifically including:

[0013] (41). First, according to the ecological water level threshold control value H c in Step 1 and the water level burial depth L of the mine design area, obtain the critical value y of the total ecological water level decline height of all coal seams in Step 3 总 ; where the critical value y of the total ecological water level decline height of all coal seams 总 = H c - H; H is the initial underground water level burial depth;

[0014] (42). Assign the critical value to y 总 as the ecological water level subsidence value H1 to the fitting expression corresponding to the first coal seam to obtain the critical filling rate corresponding to the first coal seam Combined with the actual engineering safety factor, determine the final filling rate corresponding to the first coal seam

[0015] (43). Assign the final filling rate corresponding to the first coal seam to the fitting expression corresponding to this coal seam to obtain the extreme value H of the ecological water level subsidence corresponding to the first coal seam 1max ;

[0016] (44). Through the critical value y of the total ecological water level decline height of all coal seams in step (41) 总 , the extreme value H of the ecological water level subsidence in step (43) 1max , calculate the ecological water level subsidence value H2 = y of the second coal seam 总 - H 1max ;

[0017] (45). According to the fitting expression corresponding to the second coal seam, calculate the Combined with the actual engineering safety factor, determine the final filling rate corresponding to the second coal seam

[0018] Preferably, when the number of coal seams i > 2, after step (45), the following steps are further included:

[0019] Step 5. Assign the final filling rate corresponding to the second coal seam to the fitting expression corresponding to the second coal seam to obtain the extreme value H of the ecological water level subsidence corresponding to the second coal seam 2max ; then calculate the ecological water level subsidence value H of the i-th coal seam i ; where,

[0020] Hi = H c -H-H 1max -H 2max -…H (i-1)max ; where i ≥ 3; i = n + 1, n ≥ 2;

[0021] After that, according to the fitting expression corresponding to the i-th coal seam, the corresponding Combined with the actual engineering safety factor, determine the final filling rate corresponding to the i-th coal seam

[0022] Preferably, in step 1, the ecological water level threshold influence index K i Includes surface soil moisture content, soil salt content, vegetation coverage, vegetation protection types and vegetation protection levels.

[0023] Preferably, in step 1, the key physical and mechanical parameters of coal and rock mass include bulk modulus, shear modulus, cohesion, tensile strength, internal friction angle and density.

[0024] Preferably, in step 4,

[0025] Preferably, in step 3, in the compaction mechanical property experiment of the filling material, obtain the bulk density, elastic modulus and Poisson's ratio of the filling material.

[0026] Preferably, in step 3, use 3DEC numerical simulation software to construct a three-dimensional numerical analysis model.

[0027] Preferably, in step 3, use origin software to obtain the curve relationship diagram.

[0028] Compared with the prior art, the advantages of the present invention are:

[0029] (1) Provide a safe, reliable and practical design method for controlling the ecological water level threshold in repeated mining of coal mines, which can provide reference for controlling the ecological water level threshold and protecting the surface ecological environment in filling mining areas with fragile ecology.

[0030] (2) The design method has strong practicability, simple operation and obvious beneficial effects, which can provide theoretical and engineering reference for coal resource mining and ecological water level protection in coal mines, implement the concept of "lucid waters and lush mountains are invaluable assets", enrich the theory of green mining, and expand the application scope and effect of filling coal mining. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the design flow chart of the present invention;

[0032] Figure 2 is the schematic diagram of the design method for controlling the ecological water level threshold in repeated mining of coal mines of the present invention;

[0033] Figure 3 is the filling rate of the main mining 1# Curve graph of the relationship with the ecological water level subsidence value H1;

[0034] Figure 4 is the filling rate of the main mining 2# Curve graph of the relationship with the ecological water level subsidence value H2.

[0035] Among them, 1 - initial buried depth H of the groundwater level; 2 - ecological water level threshold control value; 3 - extreme value of ecological water level subsidence; 4 - repeatedly mined and backfilled goaf; 5 - main mining 1# coal seam; 6 - main mining 2# coal seam; 7 - initial position of the groundwater level. Specific implementation method

[0036] The design method of the ecological water level threshold control for repeated mining in coal mines of the present invention will be described in more detail below with reference to the schematic diagrams, in which the preferred embodiments of the present invention are shown. It should be understood that those skilled in the art can modify the present invention described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as a broad guidance for those skilled in the art and not as a limitation to the present invention.

[0037] A design method for ecological water level threshold control in repeated mining of coal mines includes:

[0038] Step 1: Collect the ecological water level threshold influence index K of the mine design area i , to determine the ecological water level threshold control value H c ;

[0039] Step 2: Obtain the compaction characteristics of the filling material and the key physical and mechanical parameters of the coal and rock mass under the mine geological conditions by using laboratory test methods:

[0040] Step 3: Numerical simulation:

[0041] (31) Based on the compaction characteristics of the filling material and the key physical and mechanical parameters of the coal and rock mass obtained in Step 2, construct a three-dimensional numerical analysis model;

[0042] (32) Taking different coal seams as the research objects, for each coal seam, using the filling rate as the input parameter of the three-dimensional numerical analysis model, and obtaining the ecological water level drop height H under the condition of the change of the filling rate i through the three-dimensional numerical analysis model;

[0043] (33) Statistically analyze the ecological water level drop heights H corresponding to different filling rates and the filling rate i corresponding to each coal seam;

[0044] (34) Obtain the filling rate of each coal seam based on the statistical results And the ecological water level decline height H i The curve relationship diagram therebetween, and the fitting expression corresponding to the curve relationship diagram;

[0045] Step 4. Obtain the final filling rate corresponding to each coal seam Specifically including:

[0046] (41) First, according to the ecological water level threshold control value H c in Step 1 and the water level burial depth L of the mine design area, obtain the critical value y of the total ecological water level decline height of all coal seams in Step 3 总 ; Among them, the critical value y of the total ecological water level decline height of all coal seams 总 = H c - H; H is the initial underground water level burial depth;

[0047] (42) Assign the critical value y 总 as the ecological water level subsidence value H1 to the fitting expression corresponding to the first coal seam to obtain the critical filling rate corresponding to the first coal seam Combined with the actual engineering safety factor, determine the final filling rate corresponding to the first coal seam

[0048] (43) Assign the final filling rate corresponding to the first coal seam to the fitting expression corresponding to this coal seam to obtain the extreme value H of the ecological water level subsidence corresponding to the first coal seam 1max ;

[0049] (44) Through the critical value y of the total ecological water level decline height of all coal seams in step (41) 总 , the extreme value H of the ecological water level subsidence in step (43) 1max , calculate the ecological water level subsidence value H2 = y 总 - H 1max ;

[0050] (45) According to the fitting expression corresponding to the second coal seam, find out the Combined with the actual engineering safety factor, determine the final filling rate corresponding to this second coal seam

[0051] Preferably, when the number of coal seams i > 2, after step (45), the following steps are further included:

[0052] Step 5. Assign the final filling rate corresponding to the second coal seam Assign to the fitting expression corresponding to the second coal seam to obtain the extreme value H of the ecological water level subsidence corresponding to the second coal seam 2max ; Then calculate the ecological water level subsidence value H corresponding to the i-th coal seam i ; Among them,

[0053] H i =H c -H-H 1max -H 2max -…H (i-1)max ; Among them, i≥3; i=n + 1, n≥2;

[0054] Then, according to the fitting expression corresponding to the i-th coal seam, calculate the corresponding Combined with the actual engineering safety factor, determine the final packing rate corresponding to the i-th coal seam

[0055] Preferably, in step 1, the ecological water level threshold influence index K i includes surface soil moisture content, soil salt content, vegetation coverage, vegetation protection types and vegetation protection levels.

[0056] Preferably, in step 1, the key physical and mechanical parameters of the coal rock mass include bulk modulus, shear modulus, cohesion, tensile strength, internal friction angle and density.

[0057] Preferably, in step 4,

[0058] Preferably, in step 3, in the compaction mechanical property experiment of the filling material compaction characteristics, obtain the bulk density, elastic modulus and Poisson's ratio of the filling material.

[0059] Preferably, in step 3, use 3DEC numerical simulation software to construct a three-dimensional numerical analysis model.

[0060] Preferably, in step 3, use origin software to obtain the curve relationship diagram.

[0061] Example 1

[0062] A design method for controlling the ecological water level threshold in repeated mining of coal mines is mainly a design method for the packing rate in controlling the ecological water level threshold during the repeated mining process of coal mines.

[0063] The designed production capacity of a certain mining area in the west is 1.2 Mt / a. The main coal seams to be mined are two coal seams, namely the main mined #1 coal seam and the main mined #2 coal seam. Among them, the burial depth of the main mined #1 coal seam 5 is about 85 m, and the burial depth of the main mined #2 coal seam 6 is about 115 m. The coal seam thicknesses are 4.5 m and 3 m respectively, and the initial burial depth 1 of the groundwater level is H = 2.3 m. Due to the large mining height and shallow burial depth of the coal seam, the mining-induced fissures have developed to the ground surface, greatly affecting the local mining area's surface ecological environment. Therefore, it is necessary to fill the goaf to achieve the purpose of protecting the ecological environment such as surface vegetation.

[0064] In this embodiment, the main mined #1 coal seam 5 is defined as the first coal seam, and the main mined #2 coal seam 6 is defined as the second coal seam. In other embodiments, the main mined #1 coal seam 5 can also be defined as the second coal seam, and the main mined #2 coal seam 6 can also be defined as the first coal seam. The initial position 7 of the groundwater level and the repeated mining and filling goaf 4 are as Figure 2 shown.

[0065] Combined with a design method for controlling the ecological water level threshold in coal mine mining, its specific steps are as follows:

[0066] A design method for controlling the ecological water level threshold in repeated coal mine mining includes:

[0067] Step 1: According to the data collection and on-site measurement of ecological water level threshold influence indicators K such as the surface soil moisture content, soil salt content, vegetation coverage, vegetation protection types and grades in the designed area of the mine, comprehensively determine the ecological water level threshold control value 2 (H i ) to be 4.8 m. c ) is 4.8 m.

[0068] Step 2: Adopt laboratory testing methods to obtain the compaction characteristics of the filling materials and the key physical and mechanical parameters of the coal and rock mass under the geological conditions of the mine.

[0069] Among them, in the compaction mechanical property experiment of the filling material compaction characteristics, obtain the bulk density, elastic modulus and Poisson's ratio of the filling material. The key physical and mechanical parameters of the coal and rock mass include bulk modulus, shear modulus, cohesion, tensile strength, internal friction angle and density.

[0070] Specifically, use the gangue and aeolian sand produced by this mine with a mass fraction of 1:0.3 as the granular filling material, and conduct a compaction mechanical property experiment under the condition that the original rock stress is about 2.5 Mpa, and obtain that the bulk density of this filling material is about 20.0 kN·m -3 , the elastic modulus is 16.3 GPa, and the Poisson's ratio is 0.29.

[0071] According to the geological mining conditions, overlying rock borehole data, and laboratory test results of the physical and mechanical parameters of coal and rock in the designed area of the mine, calibrate the laboratory test results of the physical and mechanical parameters of coal and rock. The calibrated physical and mechanical parameters of coal and rock are shown in Table 1.

[0072] Table 1 Physical and mechanical parameters of coal and rock

[0073]

[0074] Step 3: Numerical simulation.

[0075] (31) Based on the compaction characteristics of the filling material and the key physical and mechanical parameters of the coal rock mass obtained in Step 2, a three-dimensional numerical analysis model is constructed using 3DEC numerical simulation software; the model size is 300m × 200m × 120m in length × width × height; the horizontal displacement is restricted at the four sides, and the vertical displacement is restricted at the bottom; the constitutive relationship adopts the Mohr-Coulomb model.

[0076] (32) Taking two coal seams as the research objects, for each coal seam, the filling rate is used as the input parameter of the three-dimensional numerical analysis model, and the decline height H of the ecological water level under the condition of the change of the filling rate i is obtained through the three-dimensional numerical analysis model.

[0077] (33) Statistically analyze the decline height H of the ecological water level corresponding to different filling rates and the filling rate i .

[0078] (34) Based on the statistical results, obtain the curve relationship diagram between the filling rate of each coal seam and the decline height H i of the ecological water level, and the fitting expression corresponding to the curve relationship diagram.

[0079] In this embodiment, in order to obtain the relationship between the filling rate and the decline height of the ecological water level under the condition of repeated mining, the decline of the aquifer height H1 is simulated and calculated when the filling rate of the main mined 1# seam is 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10% and non-filling mining.

[0080] According to the simulation results under different filling rate conditions of the main mined 1# coal seam, the relationship between the filling rate and the decline height H1 of the ecological water level is shown in Table 2.

[0081] Table 2 Relationship between the filling rate and the decline height H1 of the ecological water level

[0082]

[0083] According to the obtained results, through the origin software, the filling rate The curve relationship between the ecological water level drop height H1 (such as Figure 3 As shown). At the same time, the fitting equation is:

[0084] y=-31.1x+3070.1 (1)

[0085] Among them, the correlation coefficient R 2 It is 0.99074.

[0086] Based on #2 Filling Rate The decrease of aquifer height H2 under 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10% and no filling is shown. The simulation results under different filling rate conditions are statistically analyzed. The relationship with the ecological water level drop height H2 is shown in Table 3.

[0087] Table 3 Filling rate Relationship with ecological water level drop height H2

[0088]

[0089] According to the results obtained, the main mining 2# filling rate is obtained through the origin software The curve relationship between the ecological water level drop height H2 (such as Figure 4 As shown). At the same time, the fitting equation is:

[0090] y=-27.8x+2757.3 (2)

[0091] Among them, R 2 It is 0.99702.

[0092] Step 4: Obtain the final critical filling rate corresponding to each coal seam, specifically including (41) to (45).

[0093] (41) First, according to the ecological water level threshold control value H in step 1 c and the water level depth L in the mine design area, and obtain the critical value y of the sum of the ecological water level drop heights of all coal seams in step 3 总 Among them, the critical value of the sum of the ecological water level drop heights of all coal seams (ecological water level sinking extreme value 3)y 总 =H c -H.

[0094] According to the ecological water level threshold control value H c =4.8m, the depth of the Quaternary groundwater level L is 2.3m, that is, the critical value of the groundwater level drop caused by repeated mining (the critical value of the total ecological water level drop height of all coal seams) is y 总 =H c -H=2500mm.

[0095] (42) Assign the critical value of the ecological water level sinking value H1 of 2500 mm to the fitting expression corresponding to the first coal seam (the main mined 1# coal seam 5) to obtain the critical filling rate corresponding to the No. 1 coal seam Combined with the actual engineering safety factor, determine the final filling rate corresponding to the first coal seam

[0096] When H1 = 2500 mm, that is, when y1 = 2500, substitute it into the fitting formula (1) to obtain x1 = 18.3, that is, the filling rate of the main mined 1# When it is 18.3%, it reaches the critical control value of the ecological water level threshold

[0097] Considering a certain actual engineering safety factor, according to requirements, select the final filling rate of the main mined 1# coal seam[[ID=!16]] is 45%. Further study the critical filling rate of the main mined 2# coal seam

[0098] (43) Assign the final filling rate corresponding to the first coal seam to the fitting expression corresponding to the first coal seam to obtain the extreme value H of the ecological water level sinking corresponding to the first coal seam 1max .

[0099] (44) Through the critical value of the sum of the ecological water level drop heights of all coal seams in step (41), the extreme value H of the ecological water level sinking in step (43) 1max , inversely calculate the ecological water level sinking value H2 = y corresponding to the second coal seam (the main mined 2# coal seam 6) 总 -H 1max .

[0100] (45) According to the fitting expression corresponding to the second coal seam, find out the critical filling rate corresponding to the No. 2 coal seam (x2); combined with the actual engineering safety factor, determine the final filling rate corresponding to the second coal seam

[0101] That is, when x1 = 45%, y1 = H 1max = 1670.6, that is, when y2 = H2 = H c -H-H 1max = 829.9, substitute it into the fitting formula (2) to obtain x2 = 69.3

[0102] Considering a certain actual engineering safety factor, according to requirements, select the final filling rate of the main mined 2# coal seam to achieve the purpose of the ecological water level threshold control value is 75%

[0103] Example 2 It should be noted that there may be some inaccuracies in the translation due to the complexity and potential ambiguity of the original text, especially in some technical and context-dependent expressions. It is recommended to review and verify the translation in combination with the relevant technical knowledge and specific background.

[0104] On the basis of Embodiment 1, further solve the final filling rate of the 3# coal seam.

[0105] The solution process of the fitting formula after numerical simulation of the 3# coal seam is the same as the solution processes of the above-mentioned main mined 1# coal seam and main mined 2# coal seam, and will not be elaborated here.

[0106] That is, when x2 = 75%, y2 = H 2max = 672.3, that is, y3 = H3 = H c -H - H 1max -H 2max = 157.6.

[0107] Substitute into the fitting formula after numerical simulation of the 3# coal seam to obtain x3, and thus select the final filling rate of the 3# coal seam By analogy, the final filling rates when other coal seams are mined can be obtained Design value.

[0108] The above are only the preferred embodiments of the present invention and do not impose any limitation on the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification and other changes to the technical solution and technical content disclosed by the present invention, all of which fall within the content of the technical solution of the present invention and are still within the protection scope of the present invention.

Claims

1. A design method for controlling the ecological water level threshold in repeated mining of coal mines, characterized in that, Including: Step 1: Collect the ecological water level threshold impact index K of the mine design area i to determine the ecological water level threshold control value H c ; Step 2: Obtain the compaction characteristics of the filling material and the key physical and mechanical parameters of the coal and rock mass under the mine geological conditions by using laboratory testing methods; Step 3: Numerical simulation: (31) Based on the compaction characteristics of the filling material and the key physical and mechanical parameters of the coal and rock mass obtained in Step 2, construct a three-dimensional numerical analysis model; (32)Taking different coal seams as the research objects, for each coal seam, the filling rate is used as the input parameter of the three-dimensional numerical analysis model, and the decline height H of the ecological water level under the condition of the change of the filling rate is obtained through the three-dimensional numerical analysis model i ; (33) Statistically analyze the different filling rates corresponding to each coal seam Filling rate Corresponding ecological water level decline height H i ; (34) Obtain the filling rate of each coal seam based on the statistical results and the ecological water level decline height H i the curve relationship diagram therebetween, and the fitting expression corresponding to the curve relationship diagram; Step 4: Obtain the final compaction rate corresponding to each coal seam Specifically, it includes: (41) First, according to the ecological water level threshold control value H in step 1 c and the water level burial depth L of the mine design area, obtain the critical value y of the total ecological water level decline height of all coal seams in step 3 总 ; among them, the critical value y of the total ecological water level decline height of all coal seams 总 = H c - H; H is the initial underground water level burial depth; (42) Assign the critical value to y 总 As the fitting expression corresponding to the ecological water level sinking value H1 to the first coal seam, to obtain the critical filling rate corresponding to the first coal seam Combined with the actual engineering safety factor, determine the final filling rate corresponding to the first coal seam (43) Assign the final filling rate corresponding to the first coal seam to the fitting expression corresponding to this coal seam to obtain the extreme value H of the ecological water level subsidence corresponding to the first coal seam 1max ; (44) The critical value y of the sum of the ecological water level decline heights of all coal seams in step (41) 总 , the extreme value H of the ecological water level subsidence in step (43) 1max , calculate the ecological water level subsidence value H2 corresponding to the second coal seam as H2 = y 总 - H 1max ; (45) According to the fitting expression corresponding to the second coal seam, find out the Combined with the actual engineering safety factor, determine the final packing rate corresponding to the second coal seam 2. The design method for controlling the ecological water level threshold in repeated mining of coal mines according to claim 1, characterized in that, When the number of coal seams i > 2, the following steps are further included after Step (45): Step 5: Assign the final filling rate corresponding to the second coal seam to the fitting expression corresponding to the second coal seam to obtain the extreme value H of the ecological water level subsidence corresponding to the second coal seam 2max ; then calculate the ecological water level subsidence value H corresponding to the i-th coal seam i ; where H i = H c -H-H 1max -H 2max -…H (i-1)max ; where i ≥ 3; i = n + 1, n ≥ 2; After that, according to the fitting expression corresponding to the i-th coal seam, the combined with the actual engineering safety factor, determine the final packing rate corresponding to the i-th coal seam 3. The design method for controlling the ecological water level threshold in repeated mining of coal mines according to claim 1, characterized in that, The ecological water level threshold impact index K in Step 1 i includes surface soil moisture content, soil salt content, vegetation coverage, vegetation protection types, and vegetation protection levels.

4. The design method for controlling the ecological water level threshold in repeated mining of coal mines according to claim 1, characterized in that, In Step 1, the key physical and mechanical parameters of the coal and rock mass include bulk modulus, shear modulus, cohesion, tensile strength, internal friction angle and density.

5. The design method for controlling the ecological water level threshold in repeated mining of coal mines according to claim 1, characterized in that, In Step 4, the critical filling ratio 6. The design method for controlling the ecological water level threshold in repeated mining of coal mines according to claim 1, characterized in that, In Step 3, in the compaction mechanical property experiment of the filling material compaction characteristics, obtain the unit weight, elastic modulus and Poisson's ratio of the filling material.

7. The design method for controlling the ecological water level threshold in repeated mining of coal mines according to claim 1, characterized in that, In Step 3, use the 3DEC numerical simulation software to construct a three-dimensional numerical analysis model.

8. The design method for controlling the ecological water level threshold in repeated mining of coal mines according to claim 1, characterized in that, In Step 3, use the origin software to obtain the curve relationship diagram.

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