Mining and charging integrated mining and charging working face alternate mining method

Abstract

The present application relates to coal mining method field, especially a kind of underground mining and filling integrated mining and filling working face interphase coal mining method.Firstly, transport roadway and air return roadway are excavated;Interval arrangement filling working face and longwall working face with suitable width;Then, advancing type stoping and filling of filling working face are carried out;After the stoping and filling of filling working face on both sides are completed, and transport crossheading and air return crossheading are left for longwall working face, longwall working face is mined by retreating type full caving method;Such mining is carried out for the whole mine seam.The present application uses narrow face for filling working face, and uses wide face for longwall working face, so that coal production demand, gangue production capacity and crossheading intensity demand are matched.Filling working face uses advancing type mining, and uses filling body to form crossheading and crossheading directly, which are used for retreating type mining of longwall working face, and the whole coal mining process almost does not need to excavate crossheading, and the crossheading intensity formed by filling body is large, which reduces support workload and can ensure safety.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coal mining methods, in particular to a coal mining method for underground mining, selecting and filling integrated mining and filling working faces. BACKGROUND

[0002] Coal is an important non-renewable energy source, which plays an important role in industrial production. The common coal mining method is underground longwall comprehensive mechanized coal mining method, which is suitable for the layout of mining area and belt area working face. Generally, a section coal pillar with a width of about 20m is left between the working faces, and the width of the section coal pillar needs to be increased continuously with the increase of the mining depth of the coal seam. Taking a working face width of 200m as an example, if a section coal pillar with a width of 20m is left, the coal recovery rate of the whole mining area or belt area is only about 90%. Taking a working face recovery length of 1000m, a mining height of 5m and a density of 1.5 tons / m 3 As an example, about 150,000 tons of coal are wasted for each working face recovery. Therefore, the mining method with section coal pillar has great energy waste. The gob-side entry technology can be used without leaving a section coal pillar or leaving a very narrow section coal pillar, but the support of the gob-side entry is difficult, the maintenance is difficult, and the support difficulty of the gob-side entry technology increases continuously with the increase of the mining depth of the coal seam.

[0003] At the same time, in line with the trend of green coal mining, how to reduce the damage to the environment as much as possible during coal mining is a hot spot of existing researchers. For example, the emerging underground mining, selecting and filling integrated technology arranges the traditional surface coal selection underground, and the waste such as gangue and tailings generated during the selection can be directly filled in the goaf without lifting to the surface, which can greatly reduce the gangue lifting cost and the problem of gangue occupying land for stacking. However, the amount of filling material obviously cannot fill all the goafs generated after the working face is mined, so the existing technology is generally unplanned for goaf filling operation, as long as the gangue is not lifted to the surface. SUMMARY

[0004] For the deficiencies of the above-mentioned traditional underground longwall comprehensive mechanized coal mining method and the existing underground mining, selecting and filling integrated technology, if the two can be combined together, mutual complementation, taking advantages and avoiding disadvantages, great production efficiency can be generated. For this purpose, the inventors propose a coal mining method for underground mining, selecting and filling integrated mining and filling working faces, which specifically includes the following steps:

[0005] First step: excavate the transportation roadway and the return air roadway along the strike from the shaft bottom station;

[0006] Second step: interval arrangement of filling working face and longwall working face along the strike;

[0007] Third step, respectively determine the appropriate filling working face width W1 and the coal mining working face width W2;

[0008] Fourthly, the coal preparation and filling material preparation system is constructed in the shaft bottom station;

[0009] Fifthly, the advancing mining and filling of the filling face are carried out;

[0010] Sixthly, after the mining and filling of the filling faces on both sides are completed, the longwall face is mined by the retreating fully caving method, and the transportation crossheading and the air return crossheading are left for the longwall face;

[0011] Seventhly, the fifth step and the sixth step are repeated to mine the coal seams in the whole mine.

[0012] As a further optimization of the above scheme, in the first step, the transportation roadway is connected with the main shaft, and the air return roadway is connected with the auxiliary shaft.

[0013] As a further optimization of the above scheme, in the second step, the production progress of the filling face is consistent with that of the longwall face.

[0014] As a further optimization of the above scheme, in the second step, the total width W of the filling face and the longwall face is determined according to the production capacity requirement of the mine and the actual production capacity of the mine.

[0015] As a further optimization of the above scheme, in the third step, the amount of the filling material that can be produced per day is determined according to the daily gangue production and the proportion of the gangue in the filling material, and then the width W1 of the filling face is determined according to the filling speed of the filling face, and the width of the longwall face is W-W1.

[0016] As a further optimization of the above scheme, in the third step, when the stability of the filling body is insufficient, the top cutting borehole is constructed from the crossheading on both sides to the bottom interface of the curved subsidence zone along the inclination, the included angle β' between the top cutting borehole and the coal seam plane is greater than the original caving angle β of the rock stratum.

[0017] As a further optimization of the above scheme, in the fourth step, the coal preparation and filling material preparation system includes a coal and gangue separation system to separate clean coal and gangue, and the gangue is crushed into a suitable particle size by a gangue crushing system, and the cementing material, the crushed gangue and water are transported to the filling material preparation system for stirring and preparation of the filling material.

[0018] As a further optimization of the above scheme, in the fifth step, the transportation gate road is excavated from the transportation main roadway to the protective coal pillar boundary, the return air gate road is excavated from the return air main roadway to the protective coal pillar boundary, and a continuous miner is used for coal mining, and the mined coal is transferred to the belt conveyor in the transportation gate road by a shuttle car; the lagging coal mining area is provided with a gate road formwork along the inclination on both sides, a filling retaining wall is constructed perpendicularly to the gate road formwork, a filling space is formed between the filling retaining wall and the filling body formed by the previous filling, filling material is filled, and after the filling material is solidified to a predetermined strength, the gate road formwork is pulled out to the next filling space section.

[0019] As a further optimization of the above scheme, in the fifth step, the filling pipe enters the return air main roadway from the shaft bottom station, and then is laid to the filling area from the return air gate road; a ∩-shaped or door-shaped gate road formwork is used, and the ∩-shaped or door-shaped gate road formwork connects the gate road and the coal mining area.

[0020] The invention point and beneficial effects of the present application are as follows:

[0021] 1. The present application adopts a zone type working face arrangement scheme as a whole, which is suitable for the mining of near-horizontal coal seams. Among them, the filling working face and the longwall working face are arranged at intervals, the filling working face adopts a narrow face, the longwall working face adopts a wide face, and a method for determining the width of the filling working face and the longwall working face is given, so that the coal production demand, the gangue production capacity, and the gate road strength demand are matched.

[0022] 2. A simple method for calculating the overburden load borne by the filling body is given, and a top cutting method for reducing the load borne by the filling body is given based on the calculation method.

[0023] 3. The present application realizes the whole process of mining and selecting filling underground, the gangue does not go up the shaft, avoiding the occupation of arable land by gangue accumulation on the ground; at the same time, the filling working face adopts advancing mining, the transportation gate road and the return air gate road are directly generated by the filling body, and are used by the longwall working face, the whole coal mining process does not need to excavate the gate road during the mining of the working face, and the strength of the gate road formed by the filling body is greater than that of the traditional gob-side entry, which reduces the supporting workload and ensures safety. BRIEF DESCRIPTION OF DRAWINGS

[0024] When considered in conjunction with the accompanying drawings, a more complete and thorough understanding of the present application can be achieved and many of the accompanying advantages thereof will be more fully understood by referring to the following detailed description, taken in conjunction with the accompanying drawings in which:

[0025] Figure 1 —the present application is a schematic diagram of the whole arrangement plane of the underground mining and selecting filling integrated mining and filling working face;

[0026] Figure 2- The underground mining, dressing and filling integrated mining and filling working face interphase coal mining method filling body stress schematic diagram;

[0027] Figure 3 - The underground mining, dressing and filling integrated mining and filling working face interphase coal mining method shaft bottom yard enlarged schematic diagram;

[0028] Figure 4 - The underground mining, dressing and filling integrated mining and filling working face interphase coal mining method filling working face enlarged schematic diagram;

[0029] Figure 5 - The underground mining, dressing and filling integrated mining and filling working face interphase coal mining method longwall working face enlarged schematic diagram;

[0030] BRIEF DESCRIPTION OF DRAWINGS: 1 - haulage roadway; 2 - return air roadway; 3 - return air gate; 4 - haulage gate; 5 - first stoping boundary; 6 - second stoping boundary; 7 - filling working face; 71 - continuous miner; 72 - shuttle car; 73 - gate module; 74 - belt conveyor; 75 - filling pipe; 76 - filling retaining wall; 77 - filling body; 78 - filling space; 8 - longwall working face; 81 - hydraulic support; 82 - drum shearer; 9 - shaft bottom yard; 91 - main shaft; 92 - auxiliary shaft; 93 - coal and gangue separation system; 94 - clean coal storage bin; 95 - gangue crushing system; 96 - cementing material storage system; 97 - water bin; 98 - filling material preparation system; 10 - coal seam; 11 - goaf; 12 - curved subsidence zone; 13 - water flowing fractured zone; 14 - caving zone. DETAILED DESCRIPTION

[0031] In order to better understand the technical content of the present application, specific embodiments are described below with reference to the accompanying drawings. In the present application, aspects of the present application are described with reference to the accompanying drawings, which show many illustrative embodiments. The embodiments of the present application are not limited to the drawings described. It should be understood that the present application is realized by any one of the above-mentioned concepts and embodiments, and the concepts and embodiments described in detail below, because the concepts and embodiments disclosed in the present application are not limited to any embodiment. In addition, some aspects disclosed in the present application can be used alone, or in any suitable combination with other aspects disclosed in the present application.

[0032] As Figures 1-5 shown, the underground mining, dressing and filling integrated mining and filling interphase coal mining method of the present application comprises the following steps:

[0033] The first step is that two parallel main roads are excavated along the strike from the well bottom yard 9, which are respectively a transportation main road 1 and a return air main road 2, wherein the transportation main road 1 is located at the shallow part of the tendency, the return air main road 2 is located at the deep part of the tendency, the interval of the transportation main road 1 and the return air main road 2 can be determined by referring to the Coal Mine Safety Regulations, and the interval selected is generally 30-50m, the transportation main road 1 is communicated with the main shaft 91, and is mainly used for air intake, coal transportation and pedestrian; the return air main road 2 is communicated with the auxiliary shaft 92, and is mainly used for air return, drainage and arrangement of filling pipe lines;

[0034] A suitable main road protection coal pillar is reserved, the recovery of the coal seam 10 will have an influence on the stability of the main road, in order to protect the main road, a certain width of the main road protection coal pillar is generally reserved to reduce the influence of the recovery of the coal seam 10 on the main road, thereby facilitating the maintenance of the main road, that is, the recovery area of the coal seam 10 needs to keep a certain distance from the main road; the coal mining method of the present application forms a protection coal pillar between the first recovery boundary 5 and the transportation main road 1, the first recovery boundary 5 is parallel to the transportation main road 1, and the width of the main road protection coal pillar can be determined by referring to the Coal Mine Safety Regulations, and the interval selected is generally 30-50m, that is, the interval between the first recovery boundary 5 and the transportation main road 1 is 30-50m.

[0035] The second recovery boundary 6 is determined according to the occurrence of the coal seam 10, the mining boundary of the mine, the mining plan of the mine, the demand of the mine capacity and the like, the second recovery boundary 6 is parallel to the first recovery boundary 5, forming a tendency recovery range of the strip area, the tendency shallow part is the second recovery boundary 6, and the tendency deep part is the first recovery boundary 5.

[0036] The second step is that the filling working face 7 extending along the tendency and the longwall working face 8 are arranged at intervals along the strike, the filling working face 7 is adjacent to the longwall working face 8, each filling working face 7 is flanked by the longwall working face 8, each longwall working face 8 is flanked by the filling working face 7, the longwall working face 8 adopts the fully caving method comprehensive mechanized coal mining technology, and the filling working face 7 adopts the filling coal mining technology for recovery and filling;

[0037] The production progress (recovery and filling) of the filling working face 7 is consistent with the production progress (recovery) of the longwall working face 8, that is, the time for completing the recovery and filling of one filling working face 7 is basically the same as the time for completing the recovery of one longwall working face 8, or the time for completing the recovery and filling of one filling working face 7 is slightly less than the time for completing the recovery of one longwall working face 8; the recovery and filling of the filling working face 7 form the transportation crossheading 4 and the return air crossheading 3 on both sides of the strike, respectively, which are used as the transportation crossheading 4 and the return air crossheading 3 for the recovery of the longwall working face 8 on both sides of the strike of the filling working face 7;

[0038] According to the production capacity requirement of the mine and the actual production capacity of the mine, the total width W of a filling working face 7 and a longwall working face 8 is determined; wherein the production capacity requirement of the mine is the amount of coal that needs to be produced by the mine per year, and the actual production capacity of the mine is the daily production capacity that can be achieved based on the existing coal mining equipment, manual cooperation, etc., which can refer to the amount of coal that can be mined by the drum coal mining machine 82 of the longwall working face 8 and the continuous coal mining machine 71 of the filling working face 7 in one day;

[0039] Taking the mine production capacity requirement of 3 million tons / year as an example, assuming that the actual annual production time is 300 days, 10,000 tons of coal need to be produced per day; if the average mining height of the coal seam 10 is 5 m, the coal mining equipment can advance 5 cuts of coal per day, each cut is 0.8 m, and the density of the coal is 1.5 tons / m 3 , the width of the mined coal body is 333 m, that is, the total width W of one filling working face 7 and one longwall working face 8 is 333 m.

[0040] Third step, determine the width W1 of the filling working face 7 and the width W2 of the coal mining working face 8, according to the daily coal mining amount, the coal gangue content, the tailings gangue amount generated by the daily coal preparation can be determined, the gangue amount generated by other production processes can be determined, and the total gangue amount that can be generated per day can be obtained; according to the proportion of the cementing material (cement, fly ash and its auxiliary materials, such as early strength agent, etc.) and the gangue in the filling material, the amount of filling material that can be produced per day can be determined, and further according to the filling speed of the filling working face 7, the width of the filling working face 7 can be determined, and the width at this time is defined as the first width (including the width of the transportation crossheading 4 and the return air crossheading 3); wherein the filling speed of the filling working face 7 is the same as the mining speed;

[0041] Assuming that the total gangue amount generated by the mine per day is 1,000 tons, and according to the weight proportion of the gangue in the filling material, which is about 65%, the mass of the filling material that can be produced per day is determined to be 1,538 tons, and the specific gravity of the filling material is generally about 1.8 tons / m 3 , the volume of the filling material that can be produced per day is 854 m 3 , the width of the filling body is about 43 m, plus the width of the transportation crossheading 4 of 5 m and the width of the return air crossheading 3 of 5 m, the width of the filling working face 7 is W1, which is 53 m;

[0042] For example Figure 2As shown, when the longwall face 8 on both sides of the filling body 77 is mined, the filling body 77 will bear the maximum overburden load, if the filling body 77 is unstable at this time, it will lead to the crossheading of the longwall face 8 mined later to be unstable, and even affect the mining of the longwall face 8 near the filling body 77, therefore, the filling body 77 must ensure sufficient strength to ensure that the longwall face 8 on both sides is not unstable after mining;

[0043] For this purpose, the present application provides a method for determining the stability of the filling body 77: first, determine the average overburden load borne by the filling body 77: after the longwall face 8 on both sides of the filling body 77 is mined, the rock stratum of the caving zone 14 and the water flowing fractured zone 13 collapses into the goaf 11, while the rock stratum corresponding to the caving zone and the water flowing fractured zone on the filling body 77 does not collapse, forming a caving interface between the two, the angle between the caving interface and the coal seam plane is the caving angle β; it is determined that the weight of the rock stratum between the two caving interfaces on the upper part of the filling body 77 is borne by the filling body 77, such as the solid inverted trapezoid in Figure 2 , and the weight of the rock stratum of the curved subsidence zone in the two vertical planes intersecting the caving interface and the bottom surface of the curved subsidence zone 12 is also borne by the filling body 77, such as the solid rectangular area on the solid inverted trapezoid in Figure 2 ; assuming that the weight of the above rock stratum uniformly acts on the filling body 77, the average overburden load P borne by the filling body 77 can be calculated; then, the strength σ of the filling body 77 is determined; when P = σ, the critical width a of the filling body 77 to maintain stability can be calculated, and the sum of the width of the two transportation crossheadings and the width of the return air crossheading is defined as the second width;

[0044] The calculation formula of the average overburden load P borne by the filling body 77 is

[0045]

[0046] In the formula, P is the average overburden load borne by the filling body 77, MPa; γ is the average unit weight of the overburden, MN / m 3 ; a is the width of the filling body 77, m; β is the caving angle of the rock stratum; h k is the thickness of the caving zone, m; h d is the thickness of the caving zone, m; h w is the thickness of the curved subsidence zone, m.

[0047] When the first width is greater than or equal to the second width, the first width is taken as the width of the filling face 7, and the width of the longwall face 8 is W-W1, that is, the width W2 of the longwall face 8 is 280 m (excluding the two side crossheadings), and the longwall face 8 is directly mined without taking the top cutting measure;

[0048] When the first width < the second width, the first width is taken as the width of the filling face 7, and the longwall face 8 width is W-W1, i.e. the width W2 of the longwall face 8 is 280 m (excluding the two side entries); meanwhile, the top cutting boreholes are constructed along the direction (dip) of the two side entries, the top cutting boreholes are constructed from the two side entries to the bottom interface of the bending and sinking zone 15, the angle between the top cutting boreholes and the coal seam plane is β', the angle β' is greater than the caving angle β, the hydraulic fracturing or blasting is conducted through the top cutting boreholes, the position of the rock caving interface is artificially changed, the rock caving angle is changed from β to β', the modified rock caving angle β' and the range of the rock stratum borne by the filling body 77 are shown by the dashed line in Figure 2 Based on β', the overburden load P' borne by the filling body 77 is calculated, so that P' ≤ σ.

[0049] The fourth step is to construct the coal preparation and filling material preparation system in the shaft bottom station 9, as shown in Figure 3 The coal gangue separation system 93 is used to separate the mined coal, separate the clean coal and the gangue, the clean coal is stored in the clean coal storage bin 94 and transported to the ground through the main shaft 91, the gangue is crushed into a suitable particle size through the gangue crushing system 95, the cementing material is transported from the main shaft 91 and stored in the cementing material storage system 96, the cementing material includes fly ash, cement, early strength agent and other additives, the cementing material, the crushed gangue and water are transported to the filling material preparation system 98 for stirring to prepare the filling material, the water bin 97 is constructed in the shaft bottom station for storing the water for preparing the filling material, and the water produced in the mine production is pumped from the air return roadway 2 to the water bin 97 for storage. The coal separation technology and equipment, the gangue crushing equipment and the entire underground coal preparation and filling material preparation system are prior art, which will not be described here.

[0050] The fifth step is to construct the filling face 7, as shown in Figure 4As shown, the advancing mining and filling of the filling working face 7 is carried out, that is, the coal mining and filling are carried out in the direction away from the main roadway; the transportation crossheading 4 is excavated from the transportation main roadway 1 to the first mining boundary 5, the air return crossheading 3 is excavated from the air return main roadway 2 to the first mining boundary 5, the open-off cut is connected with the transportation crossheading 4 and the air return crossheading 3, the continuous miner 71 is used to carry out the mining of the coal seam 10 from the open-off cut, the mined coal is transferred to the belt conveyor 74 in the transportation crossheading 4 by the shuttle car 72, and then is transferred to the belt conveyor in the transportation main roadway 1, and is transported to the coal and gangue sorting system 93 in the shaft bottom station 9; the ∩-shaped or door-shaped crossheading formwork 73 is arranged on both sides of the mining area along the dip at a certain distance behind the mining area, the filling retaining wall 76 is constructed perpendicularly to the crossheading formwork 73, the filling space 78 is formed at a certain distance between the filling retaining wall 76 and the filling body 77 formed by the previous filling, the length of the crossheading formwork 73 is greater than the dip length of the filling space, the filling pipe 75 is used to fill the filling material into the filling space 78, after the filling material is solidified to a predetermined strength, the continuous miner 71 or the shuttle car 72 is used to pull out the crossheading formwork 73 to the next filling space section, the positions where the crossheading formwork 73 is pulled out form the air return crossheading 3 and the transportation crossheading 4 respectively, and are connected with the air return crossheading 3 and the transportation crossheading 4 formed before; the filling pipe 75 enters the air return main roadway 2 from the shaft bottom station 9, and then extends to the filling area 78 from the air return crossheading 3; before the filling, the lubricating material is smeared on the outer surface of the ∩-shaped or door-shaped crossheading formwork 73 or the isolation material is laid, so as to isolate the filling material from the outer surface of the ∩-shaped or door-shaped crossheading formwork 73, thereby facilitating the pulling out after the solidification of the filling material; the ∩-shaped or door-shaped crossheading formwork 73 connects the crossheading and the mining area; the fresh air enters the transportation main roadway 1 from the main shaft 91, and then enters the filling working face 7 from the transportation crossheading 4, the stale air enters the air return main roadway 2 from the air return crossheading 3 and is discharged to the ground by the auxiliary shaft 92; the personnel enter the filling working face 7 from the main shaft 91, the transportation main roadway 1 and the transportation crossheading 4, and return along the original route, and the water produced in the production process is transported to the water sump 97 from the air return crossheading 3 through the air return main roadway 2.

[0051] In the sixth step, as shown in FIG. 6, the ∩-shaped or door-shaped crossheading formwork 73 is pulled out to the next filling space section, and the positions where the crossheading formwork 73 is pulled out form the air return crossheading 3 and the transportation crossheading 4 respectively, and are connected with the air return crossheading 3 and the transportation crossheading 4 formed before. Figure 5As shown, the longwall face 8 is mined, and after the two side filling faces 7 are mined and filled, the transport crossheading 4 and the return air crossheading 3 are left for the longwall face 8. A open-off cut is made at the second mining boundary 6 to connect the transport crossheading 4 and the return air crossheading 3. The longwall face 8 is mined in a backward manner, i.e. towards the main roadway. Hydraulic supports 81 are arranged in the longwall face 8, and a drum shearer 82 is used to mine coal. The coal mined by the drum shearer falls on the scraper conveyor, and is then transferred to the belt conveyor in the transport crossheading 4, and then to the belt conveyor in the transport main roadway 1, and is finally transported to the coal and gangue separation system 93 in the shaft bottom station 9. Fresh air enters the transport main roadway 1 from the main shaft 91, and then enters the longwall face 8 from the transport crossheading 4. The exhaust air enters the return air main roadway 2 from the return air crossheading 3, and is discharged to the ground from the auxiliary shaft 92. People enter the longwall face 8 from the main shaft 91, the transport main roadway 1 and the transport crossheading 4, and return along the same route. Water produced during the production process is transported to the water sump 97 from the return air crossheading 3 and the return air main roadway 2.

[0052] In the seventh step, the fifth step and the sixth step are repeated to mine the coal seam 10 in the whole mine.

[0053] Of course, the above description is only for the preferred embodiments of the present application, and the present application is not limited to the above-described embodiments. It should be noted that any skilled person in the art can make all equivalent replacements and obvious modifications under the guidance of the present application, and all such replacements and modifications fall within the scope of the present application, and should be protected by the present application.

Claims

1. A coal mining method in which a mining and a stowing working face are integrated, characterized in that, The method comprises the following steps: The first step is to excavate the transportation roadway and the air return roadway along the strike from the shaft bottom station; The second step is to arrange the filling working face and the longwall working face along the strike at intervals, the production progress of the filling working face and the longwall working face is kept consistent, and the total width W of one filling working face and one longwall working face is determined according to the production capacity requirement of the mine and the actual production capacity of the mine; The third step is to determine the width W1 of the filling working face and the width W2 of the longwall working face respectively, the amount of filling material that can be produced per day is determined according to the daily gangue production and the proportion of the gangue in the filling material, the width W1 of the filling working face is determined according to the filling speed of the filling working face, and the width of the longwall working face is W-W1; when the stability of the filling body is insufficient, the top cutting borehole is constructed from the two side entries along the strike to the bottom interface of the curved subsidence zone; The method comprises the following steps: determining the average load of the overburden rock borne by the filling body, after the longwall working face on both sides of the filling body is mined, the rock stratum in the caving zone and the water flowing fractured zone collapses into the goaf, the rock stratum corresponding to the caving zone and the water flowing fractured zone on the filling body does not collapse, and a caving interface is formed between the two, the angle between the caving interface and the coal seam plane is the original caving angle β of the rock stratum, it is determined that the weight of the rock stratum between the two caving interfaces on the upper part of the filling body is borne by the filling body, and the weight of the rock stratum in the curved subsidence zone in the two vertical planes intersecting the caving interface and the bottom surface of the curved subsidence zone is also borne by the filling body, the average load P of the overburden rock borne by the filling body is calculated by assuming that the weight of the rock stratum uniformly acts on the filling body, then the strength σ of the filling body is determined, the critical width a at which the filling body remains stable is obtained when P=σ, and the second width is defined as the sum of the critical width a and the sum of the widths of the two transportation entries and the two air return entries; The calculation formula of the average load P of the overburden rock borne by the filling body is In the formula, P is the average load of overburden on the filling body, MPa; γ is the average unit weight of overburden, MN / m 3 ; a is the width of the filling body, m; β is the original caving angle of rock stratum; h k is the caving zone thickness, m; h d is the caving zone thickness, m; h w is the thickness of the curved subsidence zone, m; When the first width is greater than or equal to the second width, the first width is taken as the width of the filling working face, the width of the longwall working face is W-W1, and the longwall working face is directly mined without taking the top cutting measure; When the first width is less than the second width, the first width is taken as the width of the filling working face, the width of the longwall working face is W-W1, and the top cutting borehole is constructed at intervals along the extension direction of the two side entries, the top cutting borehole is constructed from the two side entries to the bottom interface of the curved subsidence zone, the angle between the top cutting borehole and the coal seam plane is β', β' is greater than the original caving angle β of the rock stratum, the position of the rock stratum caving interface is artificially changed by hydraulic fracturing or blasting through the top cutting borehole, the original caving angle of the rock stratum is changed from β to β', the load P' of the overburden rock borne by the filling body is calculated based on β', and P'≤σ is ensured; The fourth step is to construct the coal preparation and filling material preparation system in the shaft bottom station. In the fifth step, the advancing mining and filling of the filling face are carried out; the transportation gateway is excavated from the transportation gateway to the boundary of the protective coal pillar, the air return gateway is excavated from the air return gateway to the boundary of the protective coal pillar, the coal seam is mined by using the continuous miner, and the mined coal is transferred to the belt conveyor in the transportation gateway by using the shuttle car; the ∩-shaped or door-shaped gateway formwork is arranged along the dip in the lagging mining area on both sides, the ∩-shaped or door-shaped gateway formwork connects the air return gateway, the transportation gateway and the mining area; the filling retaining wall is constructed by using the vertical gateway formwork, the filling space is formed between the filling retaining wall and the filling body formed by the previous filling, the filling material is filled, and after the filling material is solidified to the predetermined strength, the gateway formwork is pulled out to the next filling space section; In the sixth step, after the mining and filling of the filling faces on both sides are completed, the transportation gateway and the air return gateway are left for the longwall face, and the longwall face is mined by using the retreating full caving method; In the seventh step, the fifth step and the sixth step are repeated to mine the coal seams in the whole mine.

2. The coal mining method with alternating faces according to claim 1, characterized in that: In the first step, the transportation gateway is connected with the main shaft, and the air return gateway is connected with the auxiliary shaft.

3. The coal mining method of the alternating mining of the working face with the filling of the claim of claim 1, characterized in that, In the fourth step, the coal preparation and filling material preparation system comprises a coal gangue separation system, which separates the clean coal and the gangue; the gangue is crushed into a suitable particle size by a gangue crushing system, the cementing material, the crushed gangue and water are transported to the filling material preparation system to prepare the filling material by stirring.

4. The coal mining method of the alternating mining of the working face with the drawing of coal as claimed in claim 1, characterised in that, In the fifth step, the filling pipe is laid from the shaft bottom station to the air return gateway, and then laid from the air return gateway to the filling area.

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