A method of reduced dilution coal filling

Abstract

The application discloses a kind of filling loss mining method, which comprises: determining ground surface damage control layer;According to the related parameters of the ground surface damage control layer, the advancing distance of the coal mining face is calculated;When the coal mining face advances, according to the advancing distance of the coal mining face and the related parameters of the ground surface damage control layer, the grouting position of the separation zone below the ground surface damage control layer is grouted and filled, which can realize real-time grouting and filling of the separation zone with the advancing of the working face, and the coal pillar is not needed to be set, so as to ensure the coal seam recovery rate and improve the efficiency of coal mining.

Description

Technical Field

[0001] This invention belongs to the field of coal mining technology, specifically relating to a method for reducing coal loss through backfilling. Background Technology

[0002] To prevent ground collapse caused by coal mining, coal pillars or sections are typically left during coal seam mining. Simultaneously, grouting is performed on the overburden separation layer below the key overburden stratum in the mining area. The coal pillar can be either mined back or retained. The specific steps are as follows: First, determine the key overburden stratum in the mining area using exploration data; second, determine a reasonable inclined length for the mining face; third, conduct zoned skip mining, mining sections on both sides of the coal pillar first; fourth, while the working faces of the two sections are being pushed forward, parallel operations are carried out without leaving coal pillars, and a pre-placed filling strip is constructed along the coal wall in the roadway on the side of the working face closest to the coal pillar; fifth, after the first and third sections have been mined and grouting completed for 3 to 6 months, the middle section is mined back.

[0003] However, the above method employs a zoned, skip-mining approach. After the first and third sections are mined and grouting is completed for 3 to 6 months, mining the middle section requires multiple relocations of the working face equipment, impacting working face production efficiency. Furthermore, mining requires waiting 3 to 6 months for the strata to fully subside and stabilize, affecting coal mining efficiency. In addition, without coal pillars, the coal recovery rate will be low.

[0004] There is an urgent need for a method of coal mining that reduces losses through backfilling. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to improve coal mining efficiency while ensuring a high coal seam recovery rate.

[0006] To address the above problems, this invention provides a method for reducing coal loss through backfilling.

[0007] In a first aspect, the present invention provides a method for reducing coal loss through backfilling, comprising the following steps:

[0008] Identify the surface damage control layer;

[0009] The advance distance of the coal mining face is calculated based on the relevant parameters of the surface damage control layer.

[0010] During the advancement of the coal mining face, grouting is performed at the grouting locations in the separation area below the surface damage control layer, according to the advancement distance of the coal mining face and the relevant parameters of the surface damage control layer.

[0011] According to an embodiment of the present invention, preferably, during the advancement of the coal mining face, grouting is performed at the grouting location in the separation area below the surface damage control layer according to the advancement distance of the coal mining face and the relevant parameters of the surface damage control layer, including:

[0012] When the coal mining face advances the aforementioned distance for the first time, grouting is performed at the grouting location in the separation area below the surface damage control layer.

[0013] According to an embodiment of the present invention, preferably, the relevant parameters of the surface damage control layer include the safe span of the surface damage control layer. During the advancement of the coal mining face, grouting is performed at the grouting locations in the separation area below the surface damage control layer according to the advancement distance of the coal mining face and the relevant parameters of the surface damage control layer, including:

[0014] After the coal mining face advances the first distance, each time the coal mining face advances the preset distance, grouting is performed at the grouting location in the separation area below the surface damage control layer. The preset distance is less than the safe span of the surface damage control layer.

[0015] According to an embodiment of the present invention, preferably, the preset distance is half of the safe span of the surface damage control layer.

[0016] According to an embodiment of the present invention, preferably, the grouting location in the delamination area below the surface damage control layer includes:

[0017] When the coal mining face advances the advance distance for the first time, the grouting position in the separation area below the surface damage control layer is the midpoint of the advance distance;

[0018] After the coal mining face advances the first distance, whenever the coal mining face advances the preset distance, the grouting position in the separation area below the surface damage control layer is the position where the midpoint of the advance distance is moved forward by the preset distance.

[0019] According to an embodiment of the present invention, preferably, calculating the advance distance of the coal mining face based on relevant parameters of the surface damage control layer includes:

[0020] The limit span of the surface damage control layer is calculated based on the relevant parameters of the surface damage control layer.

[0021] The safe span of the surface damage control layer is determined based on the limit span of the surface damage control layer.

[0022] The advance distance of the coal mining face is calculated based on the safe span of the surface damage control layer.

[0023] According to an embodiment of the present invention, preferably, the limiting span of the surface damage control layer is calculated based on relevant parameters of the surface damage control layer using the following expression:

[0024]

[0025] Where L is the limiting span of the surface damage control layer, h is the thickness of the surface damage control layer, and R is the ground surface damage control layer. t Let q be the tensile strength of the surface damage control layer, and q be the load above the surface damage control layer.

[0026] According to an embodiment of the present invention, preferably, the safe span of the surface damage control layer is determined based on the limiting span of the surface damage control layer using the following expression:

[0027] L0 = ηL

[0028] Where L0 is the safe span of the surface damage control layer, L is the limit span of the surface damage control layer, and η is the safety factor.

[0029] According to an embodiment of the present invention, preferably, the advancing distance of the coal mining face is calculated based on the safe span of the surface damage control layer using the following expression:

[0030] d=2Hcotφ+L0

[0031] Where d is the advancing distance of the coal mining face, L0 is the safe span of the surface damage control layer, and H is the distance between the surface damage control layer and the coal seam. The average fracture angle of the rock strata.

[0032] According to an embodiment of the present invention, preferably, determining a surface damage control layer includes:

[0033] Based on geological exploration data of the mining area, the location, thickness and related physical and mechanical parameters of the hard rock strata in the overburden are determined from bottom to top.

[0034] The fracture distance of each hard rock layer is calculated based on its location, thickness, and relevant physical and mechanical parameters.

[0035] By comparing the fracture distances of various hard rock layers, the surface damage control layer is determined.

[0036] Compared with the prior art, one or more embodiments of the above solutions may have the following advantages or beneficial effects:

[0037] The filling and loss reduction coal mining method of this application determines the surface damage control layer; calculates the advance distance of the coal mining face based on the relevant parameters of the surface damage control layer; and, during the advance of the coal mining face, grouting is performed at the grouting positions of the separation area below the surface damage control layer according to the advance distance of the coal mining face and the relevant parameters of the surface damage control layer. This method enables real-time grouting and filling of the separation area as the working face advances, eliminating the need for coal pillars and ensuring coal extraction rate while improving coal mining efficiency.

[0038] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0039] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0040] Figure 1 A flowchart of the filling and loss reduction coal mining method according to Embodiment 1 of the present invention is shown;

[0041] Figure 2 A flowchart of the filling and loss reduction coal mining method according to Embodiment 2 of the present invention is shown;

[0042] Figure 3 The safe span of the surface damage control layer in Embodiment 3 of the present invention is shown;

[0043] Figure 4 This illustrates the first filling of the delamination layer below the surface damage control layer when the preset distance is L0 / 2 in Embodiment 3 of the present invention;

[0044] Figure 5 This illustrates the second filling of the delamination layer below the surface damage control layer when the preset distance is L0 / 2 in Embodiment 3 of the present invention;

[0045] Figure 6 This illustrates the third filling of the delamination layer below the surface damage control layer in Embodiment 3 of the present invention at a preset distance of L0 / 2.

[0046] In the attached diagram, 1-aeolian sand layer, 2-aquifer, 3-surface damage control layer, 4-rock strata separation layer, 5-coal seam, 6-floor plate, 7-surface grouting borehole, 8-grouting bearing body. Detailed Implementation

[0047] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that, as long as there is no conflict, the various embodiments and features in the various embodiments of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention.

[0048] Example 1

[0049] To address the aforementioned technical problems in the prior art, embodiments of the present invention provide a method for reducing coal loss through backfilling.

[0050] Reference Figure 1 The backfilling and loss reduction coal mining method of this embodiment includes the following steps:

[0051] S11, determine the surface damage control layer;

[0052] S12, calculate the advance distance of the coal mining face based on the relevant parameters of the surface damage control layer, wherein the advance distance is the maximum advance distance at which the surface damage control layer will not be broken;

[0053] S13, when the coal mining face advances the advance distance for the first time, grouting is performed at the grouting location in the separation area below the surface damage control layer;

[0054] S14, after the coal mining face advances the first advance distance, each time the coal mining face advances the preset distance, grouting is performed at the grouting location in the separation area below the surface damage control layer, wherein the preset distance is less than the safe span of the surface damage control layer.

[0055] In an embodiment of the present invention, in steps S13 and S14, the grouting location in the delamination area below the surface damage control layer includes:

[0056] When the coal mining face advances the aforementioned distance for the first time, the grouting position in the separation area below the surface damage control layer is in the middle of the separation area below the surface damage control layer along the direction of the working face advance;

[0057] After the coal mining face advances the first distance, whenever the coal mining face advances the preset distance, the grouting position in the separation area below the surface damage control layer is the position where the previous grouting position is moved a preset distance along the direction of the face advance.

[0058] In an embodiment of the present invention, step S12, calculating the advance distance of the coal mining face based on the relevant parameters of the surface damage control layer, includes:

[0059] The limit span of the surface damage control layer is calculated based on the relevant parameters of the surface damage control layer.

[0060] The safe span of the surface damage control layer is determined based on the limit span of the surface damage control layer.

[0061] The advance distance of the coal mining face is calculated based on the safe span of the surface damage control layer.

[0062] According to an embodiment of the present invention, preferably, the limiting span of the surface damage control layer is calculated based on relevant parameters of the surface damage control layer using the following expression:

[0063]

[0064] Where L is the limiting span of the surface damage control layer, h is the thickness of the surface damage control layer, and R is the ground surface damage control layer. t Let q be the tensile strength of the surface damage control layer, and q be the load above the surface damage control layer.

[0065] According to an embodiment of the present invention, preferably, the safe span of the surface damage control layer is determined based on the limiting span of the surface damage control layer using the following expression:

[0066] L0 = ηL

[0067] Where L0 is the safe span of the surface damage control layer, L is the limit span of the surface damage control layer, and η is the safety factor.

[0068] According to an embodiment of the present invention, preferably, the advancing distance of the coal mining face is calculated based on the safe span of the surface damage control layer using the following expression:

[0069] d=2Hcotφ+L0

[0070] Where d is the advancing distance of the coal mining face, L0 is the safe span of the surface damage control layer, and H is the distance between the surface damage control layer and the coal seam. The average fracture angle of the rock strata.

[0071] In an embodiment of the present invention, step S11, determining the surface damage control layer, includes: determining the location, thickness, and related physical and mechanical parameters of the hard rock layers in the overburden from bottom to top based on geological exploration data of the mining area; calculating the fracture distance of each hard rock layer based on the location, thickness, and related physical and mechanical parameters of the hard rock layers; comparing the fracture distances of each hard rock layer to determine the surface damage control layer.

[0072] The backfilling and loss reduction mining method in this embodiment is suitable for surface ecological protection mining. It eliminates the need for coal pillars, resulting in a high coal extraction rate. The mining and backfilling processes do not interfere with each other, and the surface damage control effect is good. It can achieve coordinated underground coal resource mining and surface ecological protection.

[0073] The backfilling and loss reduction mining method in this embodiment can control the surface from destructive subsidence while efficiently developing coal resources in shallow, high-intensity mining areas. That is, backfilling is carried out when the overlying rock has completed most of the subsidence in a short period of time, so as to achieve coordinated development between underground coal resource mining and surface ecological environment protection.

[0074] Example 2

[0075] To address the aforementioned technical problems in the existing technology, this invention provides a filling and loss reduction coal mining method based on Embodiment 1, wherein the preset distance is half the safe span of the surface damage control layer.

[0076] Reference Figure 2 The backfilling and loss reduction coal mining method of this embodiment includes:

[0077] S21. Based on the geological exploration data of the mining area, determine the stratigraphic position, thickness and related physical and mechanical parameters of the surface damage control layer;

[0078] S22, the ultimate span of the surface damage control layer is calculated based on the layer position, thickness and related physical and mechanical parameters of the surface damage control layer, considering the fixed support beam. The safe span of the surface damage control layer is considered from a safety perspective, where the safe span of the surface damage control layer is L0.

[0079] S23, calculate the advancing distance of the working face based on the safe span of the surface damage control layer, where the advancing distance of the working face is d;

[0080] S24, when the working face advances a distance d from the opening, grouting is carried out in the delamination area below the surface damage control layer along the length of the working face at the middle position of the corresponding goaf on the ground surface, so that the filling body can support the surface damage control layer.

[0081] S25. Subsequently, whenever the working face advances to L0 / 2, grouting is carried out in the middle of the delamination area below the surface damage control layer until the working face mining is completed.

[0082] The filling and loss reduction coal mining method in this embodiment calculates the limit span of the surface damage control layer based on the fixed support beam, and considers the safe span of the surface damage control layer from a safety perspective, so that the advance distance of the working face calculated based on the safe span of the surface damage control layer is safe, that is, the surface damage control layer will not break when the working face advances this distance.

[0083] Example 3

[0084] To address the aforementioned technical problems in the prior art, this invention provides a backfilling and loss-reducing coal mining method based on Embodiment 1.

[0085] Reference Figures 3 to 6 The backfilling and loss reduction coal mining method of this embodiment includes:

[0086] Based on the geological exploration data of the mining area, the stratum and thickness of surface damage control layer 3 were determined, and relevant physical and mechanical parameters were obtained in the laboratory by core sampling.

[0087] The ultimate span of surface damage control layer 3 is calculated using the following expression, considering it as a fixed beam:

[0088]

[0089] Where L is the ultimate span of the surface damage control layer 3, h is the thickness of the surface damage control layer 3, and R is the maximum span of the surface damage control layer 3. t q represents the tensile strength of the surface damage control layer 3, and q represents the load above the surface damage control layer 3.

[0090] The safe span of surface damage control layer 3 is determined from a safety perspective using the following expression:

[0091]

[0092] Where L0 is the safe span of the surface damage control layer 3, h is the thickness of the surface damage control layer 3, and R... t η is the tensile strength of the surface damage control layer 3, q ​​is the load above the surface damage control layer 3, and η is the safety factor.

[0093] The advance distance of the working face is calculated based on the safe span of surface damage control layer 3:

[0094]

[0095] Where d is the advancing distance of the working face, and H is the distance between the surface damage control layer 3 and the coal seam 5. The average fracture angle of the rock strata;

[0096] When the working face advances a distance d from the opening of the coal seam 5, a filling borehole 7 is constructed along the length of the working face at the middle position of the corresponding goaf on the surface. The final position of the borehole is in the separation area 4. Then, grouting is injected into the separation area 4 below the surface damage control layer 3 through the grouting borehole 7, so that the grouting bearing body 8 can support the surface damage control layer 3 and the aquifer 2 and aeolian sand layer 1 above it.

[0097] Subsequently, whenever the working face advances a preset distance, grouting is carried out in the middle of the delamination area 4 below the surface damage control layer 3 until the working face mining is completed.

[0098] Reference Figures 3 to 6 ,exist Figure 3In this diagram, L0 represents the safe span of the surface damage control layer, d represents the advancing distance of the working face, and the delamination region 4 is formed as the working face advances. When the working face advances a distance d from the opening, grouting is performed on the delamination region 4 below the surface damage control layer 3. The grouting position is at 1 / 2 of the safe span in the advancing direction of the working face, i.e., at a distance of L0 / 2 from the layer start point. In other words, the first grouting position is at a distance of L0 / 2 from the layer start point. When the working face advances again, grouting is performed once in the middle of the delamination region 4 below the surface damage control layer 3 every time it advances a preset distance. The distance of the nth grouting position from the layer start point is as follows:

[0099] C n = [L0 + (n-1)x]n / (n+1)

[0100] Among them, C n L0 represents the distance from the nth grouting location to the starting point of the layer, L0 represents the safe span of the surface damage control layer, and x is a preset distance, which is greater than 0 and less than or equal to L0.

[0101] Figure 4 The figure shows the first filling of the delamination layer under the surface damage control layer in this embodiment. The distance from the starting point of the layer to the first filling location is L0 / 2, which is the midpoint of the delamination area, thus playing a role in balancing the delamination area. Figure 5 The second filling of the layer below the surface damage control layer in this embodiment is shown in the figure. The distance from the starting point of the layer to the location of the second filling is C2. When n = 2 and x = L0 / 2, C2 is L0. Figure 6 The figure shows the third infill of the delamination layer below the surface damage control layer in this embodiment. The distance from the third infill location to the layer starting point is C3. When n = 3 and x = L0 / 2, C2 is 3L0 / 2, and so on. Figures 4 to 6 It can be seen that the delamination area is evenly separated by the grouting positions. This design of the grouting positions can play a role in supporting the overlying rock strata. Grouting is carried out once every time the working face advances a certain distance. Grouting and underground mining are carried out separately, and the procedures do not interfere with each other.

[0102] In practical applications, the maximum preset distance x can be L0. When x = L0, the distance from the first filling position to the start of the layer is still L0 / 2, which is the midpoint of the separation zone and can support the overlying strata. The distance from the second filling position to the start of the layer is C2. When n = 2 and x = L0, C2 is 4L0 / 3. The distance from the third filling position to the start of the layer is C3. When n = 3 and x = L0, C2 is 9L0 / 4, and so on for subsequent filling positions.

[0103] In fact, the smaller the preset distance value is between 0 and L0, the more grouting positions there are in the same length of delamination area, and the smaller the interval between adjacent grouting positions, the better the filling effect of the delamination area.

[0104] In this embodiment, the filling and loss reduction coal mining method forms a bearing body by grouting and filling at a certain distance during mining. The multiple bearing bodies formed support the surface damage control layer and the rock strata above it to prevent them from breaking and sinking, thereby achieving surface ecological protection.

[0105] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A method for reducing coal loss through backfilling, characterized in that, Includes the following steps: Identify the surface damage control layer; The advance distance of the coal mining face is calculated based on the relevant parameters of the surface damage control layer. When the coal mining face advances the aforementioned distance for the first time, grouting is performed to fill the grouting location in the separation area below the surface damage control layer; After the coal mining face advances the first distance, each time the coal mining face advances the preset distance, grouting is performed at the grouting location in the separation area below the surface damage control layer. The preset distance is less than the safe span of the surface damage control layer. The grouting locations in the delamination area below the surface damage control layer include: When the coal mining face advances the advance distance for the first time, the grouting position in the separation area below the surface damage control layer is the midpoint of the advance distance; After the coal mining face advances the first distance, whenever the coal mining face advances the preset distance, the grouting position in the separation area below the surface damage control layer is the position where the midpoint of the advance distance is moved forward by the preset distance. The distance between the grouting location and the start of the layer meets the following requirements. ; in, C n For the first n The distance from each grouting location to the start of the layer. L 0 represents the safe span of the surface damage control layer. x This is the preset distance.

2. The method for reducing coal loss through backfilling according to claim 1, characterized in that, The preset distance is half the safe span of the surface damage control layer.

3. The method for reducing coal loss through backfilling according to claim 1, characterized in that, The advance distance of the coal mining face is calculated based on the relevant parameters of the surface damage control layer, including: The limit span of the surface damage control layer is calculated based on the relevant parameters of the surface damage control layer. The safe span of the surface damage control layer is determined based on the limit span of the surface damage control layer. The advance distance of the coal mining face is calculated based on the safe span of the surface damage control layer.

4. The method for reducing coal loss through backfilling according to claim 3, characterized in that, The limiting span of the surface damage control layer is calculated using the following expression based on the relevant parameters of the surface damage control layer: in, L This represents the limit span of the surface damage control layer. h The thickness of the surface damage control layer, R t The tensile strength of the surface damage control layer, q The load is above the surface damage control layer.

5. The method for reducing coal loss through backfilling according to claim 3, characterized in that, The safe span of the surface damage control layer is determined based on the limit span of the surface damage control layer using the following expression: in, L 0 represents the safe span of the surface damage control layer. L This represents the limit span of the surface damage control layer. η This is for the safety factor.

6. The method for reducing coal loss through backfilling according to claim 3, characterized in that, The advancing distance of the coal mining face is calculated based on the safe span of the surface damage control layer using the following expression: in, d The advancing distance of the coal mining face. L 0 represents the safe span of the surface damage control layer. H The distance between the surface damage control layer and the coal seam. φ The average fracture angle of the rock strata.

7. The method for reducing coal loss through backfilling according to claim 1, characterized in that, Determine the surface damage control layer, including: Based on geological exploration data of the mining area, the location, thickness and related physical and mechanical parameters of the hard rock strata in the overburden are determined from bottom to top. The fracture distance of each hard rock layer is calculated based on its location, thickness, and relevant physical and mechanical parameters. By comparing the fracture distances of various hard rock layers, the surface damage control layer is determined.

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