Coal mining and filling working face layout method based on surface subsidence control requirements

Abstract

The present application belongs to the field of coal mining, and particularly relates to a coal mining-filling working face layout method based on surface subsidence control requirements. First, the minefield is divided based on surface subsidence control requirements of different regions, and the coal mining-filling working face is arranged in the minefield region without surface subsidence control requirements. Then, for the region with surface subsidence control requirements, it is judged in turn whether the coal mining-filling working face is suitable to be arranged, whether only the filling working face is suitable to be arranged, whether the strip mining working face is suitable to be arranged, and whether the overburden separation grouting working face is suitable to be arranged, and the mining parameters can be adjusted appropriately. The present application coordinates the layout of the underground coal mining-filling working face based on the surface subsidence control requirements, fully develops the advantages of the two types of mining processes, reduces the land resource damage and ecological environment deterioration caused by coal mining, improves the coal recovery rate, provides a reference for the planning and layout of the underground coal mining-filling working face and dynamic adjustment, and is beneficial to the safe, efficient and green mining of the deep mining and selection integrated mine.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of coal mining, and particularly relates to a coal mining-filling working face layout method based on surface subsidence control requirements. BACKGROUND

[0002] Deep coal mining not only faces problems such as complex layout of development and production systems, increased gangue production, and reduced efficiency of raw coal hoisting, but also is seriously restricted by coal gangue washing and selection on the surface and ground discharge, surface subsidence, and deterioration of the ecological environment, which seriously restricts the coordinated development of coal resource development and mine environmental protection. At present, many deep mines are actively exploring new paths that can not only protect the surface environment and buildings, but also realize safe, efficient, and green mining. Underground mining and selection integrated technology is an effective method to solve the above problems. When the surface of the mine field has subsidence control requirements, the layout scheme of the underground coal mining-filling working face will become the primary problem faced by deep mining and selection integrated mines.

[0003] For coal mining working faces under the same mining conditions, as the mining depth increases, the maximum surface subsidence will gradually decrease due to the unloading expansion effect of overburden rock, but the surface subsidence influence radius will gradually increase. For filling working faces under the same mining conditions, as the mining depth increases, the compression deformation of the gangue filling body gradually increases, and the equivalent mining height and surface subsidence also increase synchronously. Deep mining and selection integrated mines should reasonably plan the positions of coal mining-filling working faces and related layout parameters according to the topography and surface features of the mine field and the maximum subsidence control requirements, so as to fully utilize the technical advantages of the two types of mining processes and reduce the impact of coal mining activities on the surface.

[0004] At present, domestic experts and scholars have carried out related research on the optimization of underground coal mining and filling working face layout, but the research mainly focuses on the classification of coal mining-filling working face layout methods and their corresponding applicable conditions, the overburden rock migration characteristics and mine pressure phenomenon law of caving-filling mixed fully mechanized mining face, the optimization layout method and size determination method of mining-filling-remaining space, the construction of selective mining technology system of "mining-selection-filling+X" integrated mine, the water preservation mining method of continuous mining and filling, and the short mining and long filling mining concept, etc. However, there is little research on the optimization layout method of coal mining-filling working face that meets different surface subsidence control requirements. Therefore, the coal mining-filling working face layout method based on surface subsidence control requirements has positive significance for ensuring safe, efficient, and green mining of deep mining and selection integrated mines, and can provide reference and guidance for the planning and dynamic adjustment of deep coal mining and filling working face layout. SUMMARY

[0005] The present application aims at land resource destruction and ecological environment deterioration caused by deep coal resource mining, and proposes a coal mining-filling working face optimization layout method suitable for different surface subsidence control requirements, which helps to improve the deep coal resource recovery rate, is suitable for coal mining-filling working face planning and dynamic adjustment in deep mining and dressing integrated mine, and is conducive to ensuring safe, efficient and green mining.

[0006] The specific steps are as follows:

[0007] a. Dividing the minefield according to the surface subsidence control requirements of different regions;

[0008] b. For the minefield region without surface subsidence control requirements, arranging the coal mining working face and the filling working face;

[0009] c. Determining the surface subsidence coefficient of each region with surface subsidence control requirements;

[0010] d. Combining with the mining parameters of the designed working face to calculate the surface subsidence value after coal mining, and judging whether the surface subsidence control requirements of the corresponding region are met; if met, arranging the coal mining working face and the filling working face in the region; if not met, reducing the mining height, but the proportion of reducing the mining height should not exceed 20% of the original mining height;

[0011] e. If the surface subsidence control requirements cannot be met, determining whether the surface subsidence control requirements of the corresponding region are met when all the designed working faces are mined with gangue filling according to the total amount of gangue in the underground and the mining parameters of the designed working face; if met, arranging all the filling working faces in the corresponding region; if not met, adjusting the mining parameters of the filling working face;

[0012] f. If the surface subsidence control requirements cannot be met, judging whether the region is suitable for arranging strip mining working face; if the surface subsidence control requirements of the region are met, arranging the strip mining working face in the region; if not met, adjusting the mining width and the reserved width of the strip mining working face, and ensuring that the recovery rate is not less than 50%;

[0013] g. If the surface subsidence control requirements cannot be met, arranging the overburden separation grouting working face in the region.

[0014] Preferably, in step a, the distribution of various objects in the surface range of the minefield is investigated, and the subsidence control requirements of the region where the objects are located are determined based on the protection requirements of the objects.

[0015] Preferably, in step a, a transition zone with a width of r is left around the region with relatively high surface subsidence control requirements, and r is the main influence radius.

[0016] Preferably, the surface subsidence control requirements are subject to the maximum surface subsidence control requirements.

[0017] Preferably, in step c, core drilling is respectively constructed in each area with surface subsidence control requirements to obtain a full columnar diagram of the rock stratum and to perform basic mechanical parameter testing to determine the basic type of the overburden rock and to further determine the surface subsidence coefficient.

[0018] Preferably, in steps b and d, the coal mining face and the filling face are arranged staggeredly.

[0019] Preferably, in steps b and d, strip compaction filling is performed along the strike of the filling face.

[0020] In step e, if the mode of adjusting the recovery parameters of the filling face is to reduce the mining height, the proportion of the reduced mining height should not exceed 20% of the original mining height.

[0021] Preferably, if it is determined according to the foregoing steps that none of the areas with surface subsidence control requirements in the minefield is suitable for the arrangement and recovery of the face by the method in the foregoing steps, the area is temporarily not arranged with a coal seam mining face.

[0022] Beneficial effects: The present application can coordinate the layout of the underground coal mining-filling face based on the surface subsidence control requirements, fully exert the technical advantages of the two types of mining processes, reduce the land resource damage and ecological environment deterioration caused by the coal resource mining, improve the coal resource recovery rate, and provide a reference for the planning and layout of the underground coal mining-filling face and dynamic adjustment, which is beneficial to the safe, efficient and green mining of the deep mining and selection integrated mine. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a layout method flowchart of the coal mining-filling face based on the surface subsidence control requirements of the present application;

[0024] Figure 2 is a boundary division schematic diagram of areas with different surface subsidence control requirements;

[0025] Figure 3 is a layout mode of the coal mining-filling face when there is no surface subsidence amount control requirement in the minefield;

[0026] Figure 4 is a schematic diagram of using the overburden rock separation grouting technology to prevent the main key layer from breaking during the coal seam mining. DETAILED DESCRIPTION

[0027] The present application will be described in more detail below with reference to the accompanying drawings. Figures 1-4 The present application will be described in more detail below with reference to the accompanying drawings.

[0028] The present application is based on the coal mining-filling working face layout method required by surface subsidence control, wherein the coal mining-filling working face refers to a coal mining working face and a filling working face, the coal mining working face refers to a working face which is not filled and mined by using the traditional full caving method, and the method is especially suitable for horizontal and near-horizontal coal seams and comprises the following steps:

[0029] a. Investigate the distribution of buildings, structures, roads, railways, water bodies, farmlands and other objects within the surface range of the minefield, and the buildings, structures, roads, railways, water bodies and farmlands occupy different areas on the surface of the minefield. Since the buildings, structures, roads, railways, water bodies and farmlands have different requirements for subsidence control, the different areas they occupy also have different requirements for subsidence control. Based on the surface subsidence control requirements of different areas, the minefield is divided.

[0030] The surface subsidence control requirements are specifically divided into the maximum allowable surface subsidence value and the maximum allowable surface horizontal movement value. The surface subsidence control requirements of different types of buildings, structures, roads, railways, water bodies and farmlands are referred to in the "Guidelines for Building, Water Body, Railway and Main Mine Roadway Coal Pillar Setting and Coal Mining under Pressure" or relevant engineering practice-related papers and other reference documents. Generally speaking, when the maximum surface subsidence meets the allowable value of the subsidence control requirement, the maximum surface horizontal movement can also basically meet the allowable value, i.e., the subsidence control requirement. Therefore, in order to simplify the division of the minefield, the minefield can be divided based on the maximum surface subsidence control requirements of different areas. The minefield can be divided into no subsidence control requirement area, maximum allowable subsidence 2.5m, 2.0m, 1.5m, 1.3m, 1.2m, 0.9m, 0.8m, etc. area based on the maximum surface subsidence control requirements of different areas.

[0031] It should be noted that different buildings have different requirements for subsidence control due to different building materials, structures, ages, etc.; different structures, roads, railways and other objects are also the same. When there are multiple objects in the same area, the highest surface subsidence control requirement applies.

[0032] In addition, as shown in Figure 2 , the surface subsidence range caused by coal seam mining is greater than the goaf range generated by coal seam mining, so when the minefield is divided based on the surface subsidence control requirements of different areas, in order to reduce the influence of coal mining activities in the area with relatively low surface subsidence control requirements on the surface subsidence in the area with relatively high surface subsidence control requirements, a transition zone with a width of r is set along the periphery of the area with relatively high surface subsidence control requirements, r is the distance from the point where the surface subsidence value is equal to 0.5 times the maximum subsidence value to the maximum subsidence point under sufficient mining conditions, i.e., the main influence radius.

[0033] The calculation formula of the main influence radius r is:

[0034] r = H / tanβ

[0035] In the formula, H is the buried depth of the coal seam, tanβ is the tangent of the main influence angle, and tanβ under different overburden conditions is referred to Guide for Coal Pillar Setting and Pressure Coal Mining of Buildings, Water Bodies, Railways and Main Roadways.

[0036] The purpose of setting the transition zone is to improve the protection of objects such as buildings, structures, highways, railways, water bodies, and farmland within the surface range of the minefield. For example, the maximum surface subsidence allowed in the area where a group of buildings is located is 1.2 m, and the range of the group of buildings and the corresponding minefield area is a rectangular area of AxB (strike x inclination). When the transition zone is set, the range of the maximum surface subsidence allowed in the area where the group of buildings is located is (A+2r1) x (r2+B+r3), r1, r2, and r3 are the main influence radius along the strike, the main influence radius along the upper part of the inclination, and the main influence radius along the lower part of the inclination, respectively.

[0037] b. As shown in Figure 1 , Figure 3 , for the minefield area without surface subsidence control requirements, a coal mining-filling working face is arranged, that is, a conventional full-caving coal mining working face and a filling working face are arranged at the same time, and the coal mining working face and the filling working face are arranged staggered to effectively reduce the maximum surface subsidence. Of course, the main purpose of arranging the filling working face here is to discharge gangue underground to ensure that the gangue does not go up the well.

[0038] The filling working face directly uses underground gangue for filling, and the gangue does not go up the well. If the amount of gangue available for filling underground is limited and cannot meet the requirement of fully compacting the goaf of the filling working face (compaction rate ), a strip compacted filling scheme is adopted for filling mining along the strike of the filling working face to ensure the surface subsidence control effect. Each strip compacted filling body extends along the strike, and different strip compacted filling bodies are distributed along the inclination.

[0039] The compaction rate is calculated as follows:

[0040]

[0041] In the formula, M0 is the height of the filling gangue after being compacted by overburden subsidence, and M b is the mining height of the filling working face.

[0042] The width d of the strip compacted filling body is

[0043]

[0044] In the formula, m bis the total amount of gangue provided for the filling working face; ε0 is the maximum compaction deformation ratio of the filling gangue, generally 0.32; n is the number of strip dense filling bodies; L s is the strike length of the filling working face; M b is the mining height of the filling working face; ρ1 is the natural bulk density of the gangue, generally 1.35 t / m 3 .

[0045] c. In each area with surface subsidence control requirements, respectively construct core drilling to obtain the full columnar diagram of the rock strata from the surface to the coal seam floor, and after the cored rock sample is prepared as a standard sample, send it to the laboratory for basic mechanical parameter testing to measure the uniaxial compressive strength, elastic modulus, ultimate tensile strength and other parameters of the rock mass, based on the overburden rock properties (mainly the lithology and uniaxial compressive strength of the main rock strata) to determine the basic type of the overburden rock, and then look up the table to determine the corresponding surface subsidence coefficient, which includes the surface subsidence coefficient q and the horizontal movement coefficient c.

[0046] The overburden rock property discrimination and the values of the surface subsidence coefficient q and the horizontal movement coefficient c refer to the "Guidelines for Building, Water, Railway and Main Roadway Coal Pillar Retention and Coal Mining Under Pressure". Specifically, the overburden rock is specifically divided into three types of hard, medium-hard and soft; the lithology of hard overburden rock is mostly Mesozoic hard sandstone and hard limestone, and others are sandy shale, shale and diabase, with uniaxial compressive strength greater than 60 MPa, corresponding to the value range of the subsidence coefficient q being 0.27-0.54 and the value range of the horizontal movement coefficient c being 0.2-0.4; the lithology of medium-hard overburden rock is mostly Mesozoic medium-hard sandstone, limestone and sandy shale, and others are soft conglomerate, dense marl and iron ore, with uniaxial compressive strength in the range of 30-60 MPa, corresponding to the value range of the subsidence coefficient q being 0.55-0.84 and the value range of the horizontal movement coefficient c being 0.2-0.4; the lithology of soft overburden rock is mostly Cenozoic sandy shale, shale, marl and loose layers such as clay and sandy clay, with uniaxial compressive strength less than 30 MPa, corresponding to the value range of the subsidence coefficient q being 0.85-1.00 and the value range of the horizontal movement coefficient c being 0.2-0.4.

[0047] d. Based on the surface subsidence coefficients of different areas with surface subsidence control requirements determined in step c, combined with the parameters such as the mining height of the working face, the coal seam inclination, the inclination length, the strike length and the like, the surface subsidence value after coal mining is calculated (including the maximum surface subsidence value W m and the maximum horizontal movement value U m), and determine whether the surface subsidence control requirements of the corresponding area are met; if met, arrange the coal mining-filling working face in the area, and stagger the arrangement of the coal mining working face and the filling working face to effectively reduce the maximum surface subsidence, and of course the main arrangement of the filling working face here is to discharge the gangue underground to ensure that the gangue does not go up the well.

[0048] wherein the maximum surface subsidence value W m is calculated by the formula:

[0049] W m = qMcosα

[0050] The maximum horizontal movement value U m of the surface is calculated by the formula:

[0051] U m = qcMcosα

[0052] In the formula, M is the mining height of the designed working face, and α is the coal seam inclination angle.

[0053] If not met, the surface subsidence value can be reduced by reducing the design working face mining height to meet the surface subsidence control requirements, wherein the proportion of reducing the mining height should not exceed 20% of the original mining height;

[0054] e. In order to reduce the waste of coal resources, when the proportion of reducing the mining height accounts for 20% of the original mining height and still cannot meet the surface subsidence control requirements in step d, according to the total amount of gangue provided for the filling working face, the designed filling working face mining height, the coal seam inclination angle, the inclination length, the strike length and other parameters, first calculate the actual filling rate of the goaf and then obtain the equivalent mining height M d of the filling working face, finally calculate the surface subsidence value (including the maximum surface subsidence value W m and the maximum horizontal movement value U m ) under the filling mining condition, and on this basis, continue to determine whether the surface subsidence control requirements of the corresponding area are met, and if met, arrange the filling working face in the area;

[0055] wherein the calculation formula of the actual filling rate of the goaf is:

[0056]

[0057] In the formula, L t is the inclination length of the filling working face.

[0058] The calculation formula of the equivalent mining height M d of the filling working face is:

[0059]

[0060] the maximum surface subsidence value W bm , the maximum horizontal movement value U bm , and the calculation formula is as follows:

[0061] W bm = qM d cos α

[0062] U bm = qcM d cos α

[0063] If the above conditions are not met, the surface subsidence value (including the maximum surface subsidence value W bm and the maximum horizontal movement value U bm ) can be reduced by adjusting the mining height, the length of the inclination, and the length of the strike of the filling working face, so that the filling working face is arranged on the basis of meeting the surface subsidence control requirements; wherein the proportion of reducing the mining height should not exceed 20% of the original mining height.

[0064] f, if the above conditions are not met, it can be determined whether the region is suitable for arranging the strip mining working face, and the strip mining parameters are designed, including the strip coal pillar width a and the strip mining width b, the strip mining surface subsidence coefficient q 条带 and the horizontal movement coefficient c 条带 are calculated, the maximum surface subsidence value W sm and the maximum horizontal movement value U sm under the strip mining condition are solved, if the surface subsidence control requirements of the region are met, the strip mining working face can be arranged in the region; if the above conditions are not met, the maximum surface subsidence value W sm and the maximum horizontal movement value U sm can be reduced by adjusting the strip coal pillar width a, so as to meet the surface subsidence control requirements, but the ratio of the strip coal pillar width a to the strip mining width b should not be greater than 50%, that is, the recovery rate should not be less than 50%;

[0065] wherein the calculation formula of the strip mining surface subsidence coefficient q 条带 is as follows:

[0066]

[0067] The calculation formula of the strip mining surface horizontal movement coefficient c 条带 is as follows:

[0068]

[0069] In the formula, ρ is the area recovery rate of the strip mining area, ρ = b / (a+b).

[0070] g. When it is determined, based on the aforementioned steps, that an area within the mining field with surface subsidence control requirements is not suitable for the working face layout and mining using the methods described in the aforementioned steps, the overburden separation grouting technology is used to prevent the main key layer from breaking, that is, the overburden separation grouting working face is arranged in this area.

[0071] like Figure 4 As shown, the specific steps of the overburden separation grouting technology are as follows: First, based on the full columnar section of the rock strata in the area and the test results of the rock mass mechanical parameters, the specific strata positions of each key layer within the overburden are determined; then, the ultimate span L of the main key layer is determined by theoretical calculation or actual measurement. p Therefore, the reasonable spacing of the ground grouting boreholes along the direction was determined to be 0.85L. p The reasonable spacing along the dip is generally 60-120m. If there is only one key layer, namely the main key layer, in the overburden, high-pressure grouting should be carried out on the closed fracture cavity below the main key layer immediately after the working face passes through the projection position of the ground borehole. If there are multiple key layers in the overburden, assuming that the key layer immediately below the main key layer is the sub-key layer m, after determining that the sub-key layer m has broken (initial breakage or periodic breakage) by combining theoretical calculations and field monitoring methods, high-pressure grouting should be carried out on the closed fracture cavity below the main key layer immediately through the ground borehole. The high-pressure grouting filling body compacts the shattered rock mass below the main key layer to form a support body based on the "supporting above and pressing down" effect, thereby preventing the main key layer from breaking and controlling surface subsidence.

[0072] The criteria for identifying key strata within the overlying strata can be found in the criteria given in "Mine Pressure and Strata Control," namely...

[0073]

[0074] In the formula, q n q n+1 These represent the loads exerted by the nth and (n+1)th rock layers on the first hard rock layer from bottom to top, respectively. j l j+1 These are the fracture step distances of the j-th and j+1-th key layers from bottom to top, respectively;

[0075] When multiple critical layers exist within the overlying strata of the working face, the critical layer closest to the coal seam mining face is usually referred to as subcritical layer 1, and the remaining critical layers are referred to as subcritical layer 2, subcritical layer 3, etc. from bottom to top. The uppermost critical layer is called the main critical layer. The relatively weak rock layers that sink and deform in tandem with each subcritical layer are referred to as weak rock layer group 1, weak rock layer group 2, weak rock layer group 3, etc. (for example, weak rock layer group 1 is located above subcritical layer 1 and below subcritical layer 2). The rock layers that sink and deform in tandem with the main critical layer are called load layers, and the rock layers that sink and deform in tandem with the main critical layer reach the surface.

[0076] The ultimate span L of the primary key layerp The calculation formula is:

[0077]

[0078] In the formula, h p is the thickness of the main key stratum, R pT is the ultimate tensile strength of the main key stratum, q p is the load borne by the main key stratum.

[0079] The calculation formula of the ultimate span of the sub-key stratum m at the initial breakage is referred to the calculation formula of the ultimate span L p of the main key stratum, the periodic breakage step distance L m of the sub-key stratum m is calculated by the following formula:

[0080]

[0081] In the formula, h m is the thickness of the sub-key stratum m, R mT is the ultimate tensile strength of the sub-key stratum m, q m is the load borne by the sub-key stratum m.

[0082] h, when it is determined according to the foregoing steps that none of the areas in the coalfield having surface subsidence control requirements is suitable for the working face arrangement and mining by the method in the foregoing steps, the areas are temporarily not arranged with coal seam mining working faces.

Claims

1. A method for the layout of a coal mining - backfilling face based on the control requirements of surface subsidence, characterised in that, Comprising the following steps: a. Dividing the minefield based on the surface subsidence control requirements of different areas; b. For the minefield area without surface subsidence control requirements, arranging the coal mining face and the filling face; c. Determining the surface subsidence coefficient of each area with surface subsidence control requirements; d. Combining with the mining parameters of the designed face to calculate the surface subsidence value after coal seam mining, and judging whether the surface subsidence control requirements of the corresponding area are met; if met, arranging the coal mining face and the filling face in the area; if not met, reducing the mining height, but the proportion of reducing the mining height should not exceed 20% of the original mining height; e、If the surface subsidence control requirements are still not met, the actual filling rate φ of the goaf is calculated according to the total amount of gangue in the well and the recovery parameters of the designed working face, and then the equivalent mining height M of the filling working face is obtained d Then the surface subsidence value under the filling mining condition is calculated, including the maximum surface subsidence value W m And the maximum horizontal movement value U m On this basis, it is further determined whether the surface subsidence control requirements of the corresponding area are met when all the designed working faces are mined by gangue filling, if met, all the filling working faces are arranged in the corresponding area; if not met, the recovery parameters of the filling working face are adjusted; Wherein, the calculation formula of the actual filling rate φ of the goaf is: ； In the formula, m b is the total amount of gangue provided for the filling working face of the mine; ε0is the maximum compaction deformation ratio of the filling gangue; ρ1is the natural bulk density of the gangue; M b is the mining height of the filling working face; L s is the strike length of the filling working face; L t is the inclination length of the filling working face; Equivalent mining height M of filling working face d The calculation formula is: ； Maximum surface subsidence W after backfilling face mining bm Maximum horizontal movement value U bm The calculation formulas are as follows: ； ； In the formula, q is the surface subsidence coefficient, and a is the coal seam inclination angle; f. If the surface subsidence control requirements still cannot be met, determining the strip mining surface subsidence coefficient and the horizontal movement coefficient, judging whether the area is suitable for arranging the strip mining face, if the surface subsidence control requirements of the area are met, arranging the strip mining face in the area; if not met, adjusting the mining width and the reserved width of the strip mining face, and ensuring that the recovery rate is not less than 50%; g. If the surface subsidence control requirements still cannot be met, arranging the overburden separation grouting face in the area; If it is determined according to the foregoing steps that the areas with surface subsidence control requirements in the minefield are not suitable for arranging the face and mining by the method in the foregoing steps, the coal seam mining face is not arranged in the area temporarily.

2. A method of coal-extraction and backfill face layout based on ground subsidence control requirements according to claim 1, characterised in that, In step a, investigate the distribution of various objects in the surface range of the minefield, and determine the corresponding subsidence control requirements of the area based on the protection requirements of various objects.

3. A method of coal mining - backfill face layout based on ground subsidence control requirements according to claim 1, characterised in that, In step a, a transition zone with a width of r is left along the periphery of the area with relatively high surface subsidence control requirements, r is the distance from the point where the surface subsidence value is equal to 0.5 times the maximum subsidence value to the maximum subsidence point under the condition of sufficient mining, that is, the main influence radius.

4. A method of coal mining - backfill face layout based on ground subsidence control requirements according to claim 1, characterised in that, The surface subsidence control requirements are subject to the maximum surface subsidence control requirements.

5. A method of coal mining - backfill face layout based on ground subsidence control requirements according to claim 1, characterised in that, In step c, core drilling is conducted in each area with surface subsidence control requirements, full columnar charts of rock strata are obtained, basic mechanical parameter tests are conducted, the basic types of overburden are determined, and the surface subsidence coefficient is determined.

6. A method of coal mining - backfill face layout based on ground subsidence control requirements according to claim 1, characterised in that, In steps b and d, the coal mining face and the filling face are arranged alternately.

7. A method of coal mining - backfill face layout based on ground subsidence control requirements according to claim 1, characterised in that, In steps b and d, strip dense filling is carried out along the strike of the filling face.

8. The method for coal mining - backfill face layout based on ground subsidence control requirements according to claim 1, characterized in that, If the way to adjust the mining parameters of the filling face is to reduce the mining height, the proportion of reducing the mining height should not exceed 20% of the original mining height.

Images