Semi-permeable membrane pack for backfilling mining and strip mining method

Abstract

The application discloses a semi-permeable membrane type filling bag for filling mining, which comprises a semi-permeable membrane type filling bag body, wherein the filling bag body is a flexible cloth bag with an internal filling slurry cuboid shape, fixed bands are uniformly distributed on the filling bag, and grouting ports of the filling bag are arranged at four corners of the top; single-layer flexible air duct cloth is adopted on the upper and lower surfaces of the filling bag, double-layer materials are adopted on the front, rear, left and right surfaces of the filling bag, the inner layer is a semi-permeable membrane material taking a textile cloth as a support body, the outer layer is flexible air duct cloth, the two cloth surfaces are sewn according to a 1m*1m square, and the area of the outer layer cloth after sewing is slightly larger than that of the inner layer. When the filling slurry is pumped, the semi-permeable membrane filters the excess water during slurry segregation, improves the filling slurry quality concentration, the excess water flows into the gap of the semi-permeable membrane, and the excess water is back osmosis into the filling slurry for hydration reaction in the coagulation process of the filling body, so that the strength of the filling body is effectively improved, and the roof contact rate of the filling body is improved.

Description

Technical Field

[0001] This invention relates to a semi-permeable membrane filling bag and a filling mining method for filling mining, belonging to the field of coal mine underground goaf filling technology. Background Technology

[0002] Compared to traditional caving-type underground coal mining, cemented backfill mining has seen rapid development in recent years due to its advantages such as resource utilization of solid waste, increased coal extraction rate, control of roof and surface subsidence, and improved safety in underground coal mines. Cemented backfill mining utilizes the inherent strength of the solidified backfill material to support the overlying rock, thereby reducing its impact on the surface. The roof contact ratio of the backfill material is directly related to the safety of the stope. If the roof contact ratio is too low, it will lead to large-scale exposure of the stope roof. When the exposed area exceeds the maximum allowable area for roof stability, it will cause roof collapse, endangering the safety of workers and the stope. Therefore, the roof contact ratio and backfill strength are key aspects of cemented backfill mining technology. The strength of the backfill material can be adjusted to meet actual requirements, while the roof contact ratio is generally improved through secondary backfilling. The main reasons why the backfill material is difficult to completely connect with the roof are as follows: ① Due to the flow characteristics of the backfill slurry itself, it is difficult for the slurry to completely fill the entire goaf. This situation is mainly reflected in the backfilling of horizontal coal seams. The backfill slurry will accumulate near the backfill pipe opening, making it difficult to fill the area far from the backfill pipe opening with slurry. In inclined coal seams, this factor has a smaller impact; ② Due to the segregation and sedimentation characteristics of the cemented backfill material itself, segregation and bleeding will occur during the backfilling process, resulting in a lower mass concentration in the upper area of ​​the backfill material. This causes the backfill material to shrink after solidification, which in turn leads to poor roof connection effect. In their study on the influence of the roof contact ratio on the stability of the filling body (Liu Qi, Ou Renze, Lin Weixing, et al. Study on the influence of the roof contact ratio on the stability of the filling body [J]. Mining and Metallurgical Engineering, 2020, 40(01):22-26.), Liu Qi et al. mentioned that when filling goaf areas with paste in my country, the roof contact ratio for primary filling is about 50%, and the roof contact ratio for secondary filling is over 80%. In order to meet the pressure requirements of the overlying strata, the roof contact ratio of the filling body in the goaf area should reach over 70%.

[0003] To prevent large-scale roof collapses in the mining area, many scholars have studied methods to improve the roof contact rate. Among them, Wang Shuhai et al. mentioned in "Research on Technical Measures to Improve the Roof Contact Rate of Backfilling" (Wang Shuhai, Li Qiyue, Zhao Guoyan. Research on Technical Measures to Improve the Roof Contact Rate of Backfilling [J]. Mining and Metallurgical Engineering, 2011, 31(01):13-15+18.) that the backfilling of goaf areas currently mostly adopts secondary and tertiary backfilling methods. However, this method is relatively labor-intensive and resource-intensive, and its application scenarios are somewhat limited. Some scholars have also cleverly designed various backfilling bags, which can solve the problem of poor roof contact caused by the fluidity of the slurry. However, these backfilling bags still solve the problem of the impact of slurry segregation and drying shrinkage on the roof contact rate by secondary backfilling. They cannot directly solve the impact of slurry segregation on the mass concentration of the backfill, and cannot replenish water or cool and cure in time during the later solidification process of the backfill.

[0004] Therefore, in order to solve a series of problems caused by the above situation, the present invention designs a semi-permeable membrane filling bag for filling mining. Summary of the Invention

[0005] This invention aims to provide a semi-permeable membrane backfill bag and a backfill mining method for backfilling. It can store excess water generated by slurry segregation by utilizing the gap between the two layers of fabric in the backfill bag. By increasing the overall mass concentration of the backfill slurry, it reduces the drying shrinkage effect of the backfill body due to solidification. After the cemented backfill material bleeds water, it can perform secondary backfilling to replenish the slurry, further improving the top contact rate of the backfill body. Furthermore, during the solidification process of the backfill body, the water between the two layers of fabric is reversed through the semi-permeable membrane back into the backfill body for hydration reaction and curing, which can improve the later strength of the backfill body.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A semi-permeable membrane filling bag for filling mining includes a flexible filling bag body, which is a rectangular flexible cloth bag that can be filled with slurry. The outer surface of the filling bag is evenly distributed with fixing straps. The slurry inlets of the filling bag are located at the four corners of the top of the filling bag. The top and bottom sides of the filling bag are made of single-layer flexible ventilation duct cloth, while the front, back, left, and right sides are made of double-layer cloth. The inner layer of the double-layer cloth is a cellulose semi-permeable membrane material with textile fabric as the support. The cellulose semi-permeable membrane has good corrosion resistance. The outer layer is a flexible ventilation duct cloth. The two layers of cloth are sewn together at the vertices according to a 1m×1m grid, and the area of ​​the outer layer of the sewn double-layer cloth is slightly larger than the area of ​​the inner layer.

[0008] The aforementioned filling bag adopts a semi-permeable membrane type filling bag. The outer layer of the filling bag body and the inner layer of the cellulose semi-permeable membrane material are both made of antistatic and flame-retardant flexible fabric, which can be used in underground coal mining.

[0009] The above-mentioned filling bag adopts a semi-permeable membrane type filling bag, and the distance between adjacent fixing straps on the outer surface of the filling bag body is selected as 90cm~110cm.

[0010] This invention provides a method for filling using the above-mentioned filling opening with a semi-permeable membrane filling bag, comprising the following steps:

[0011] (1) When a mine adopts the upward horizontal layered backfilling mining method for strip mining, the mining area is divided into two areas: the reserved strip and the extracted strip. The reserved strip plays the role of supporting the overlying rock above the mining area. When the working face completes the mining of one extracted strip, while mining the second extracted strip, the size of the first extracted strip is measured, and the backfilling bag is made according to the measured size of the extracted strip.

[0012] The design length of the filling bag is 40-60cm shorter than the actual length of the produced strip, and the design width of the filling bag is 40-60cm shorter than the actual width of the produced strip. This ensures that the gap between the outer surface of each filling bag and the surrounding rock of the produced strip is more than 20cm when the filling bags are arranged, and is used for water storage between the double-layer fabric.

[0013] (2) The prepared filling bags are transported to the underground working face through the mine's transportation system;

[0014] (3) Set up fixed anchor points on each side of the goaf according to the position of the fixing straps of the filling bag, and tie the fixing straps to the corresponding fixing anchor points;

[0015] (4) Measure the height of the four grouting ports of the filling bag that has been set up on site. Select the grouting port with the highest horizontal height among the four grouting ports for use in filling the pipeline grouting. Select the grouting port with the second highest horizontal height among the four grouting ports for venting during the filling process. Tie the other two grouting ports firmly to prevent grout leakage during the filling process.

[0016] This invention fully considers the spatial structure of the goaf (which may be a horizontal or sloping structure). Grouting ports are set at the four corners of the filling bag. During the actual filling process, the grouting port with the highest horizontal height is selected for grouting to ensure that the filling slurry can fill the internal space of the filling bag first. The grouting port with the second highest horizontal height is selected for venting to ensure that the air in the filling bag can be discharged smoothly and to ensure that the filling slurry can be pumped smoothly.

[0017] (5) After the above preparations are completed, the filling operation is started. The filling material is selected as cemented filling material. After the filling operation starts, the next goaf area can be operated in steps (1) to (4). After the filling bag is filled, the two untied grouting ports are tied first, and the next filling bag is filled.

[0018] (6) Due to the presence of the semi-permeable membrane, the excess water generated by the bleeding of the filling slurry is filtered into the gap between the two layers of fabric of the filling bag. Therefore, within 6-24 hours after the filling bag is filled, the filling bag needs to be filled again to replenish the filling slurry that is missing due to the bleeding.

[0019] (7) After the filling slurry is replenished, the secondary filling operation of the next filling bag is carried out.

[0020] The beneficial effects of this invention are:

[0021] (1) The present invention can store the excess water generated by the segregation of slurry in the gap between the double layers of cloth in the filling bag, thereby increasing the overall mass concentration of the filling slurry, reducing the drying shrinkage effect of the filling body, and effectively improving the top contact rate of the filling body.

[0022] (2) The present invention can reverse the water between the double-layer cloth back into the filling body during the solidification process of the filling body, for the hydration reaction process of the filling body, as well as the curing of the filling body, and improve the strength of the filling body;

[0023] (3) The present invention can customize filling bags of different specifications according to the actual data of the goaf site to meet the needs of on-site use;

[0024] (4) The present invention can allow the water generated by the seepage to seep out through the semi-permeable membrane and directly fill the filling bag for secondary filling, which reduces the work of excavating the grouting port and improves the top contact rate of the filling body;

[0025] (5) The present invention is ingeniously designed, easy to install, simple to use, time-saving and efficient. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the semi-permeable membrane filling bag of the present invention;

[0027] Figure 2 This is a schematic diagram of strip backfilling mining.

[0028] Figure 3 For along Figure 2 A cross-sectional view of the filling bag taken from line aa;

[0029] Figure 4 This is a schematic diagram showing the actual arrangement sequence of the filling bags;

[0030] In the diagram, 1. Single-layer fabric; 2. Double-layer fabric; 3. Sewing point; 4. Fixing tie; 5. Grouting port; 6. Fixing anchor point; 7. Filling grout; 8. Water; 9. Retained strip; 10. Mined strip. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments, but is not limited to the following embodiments. Example

[0032] like Figures 1-3 As shown, a semi-permeable membrane filling bag for filling mining includes a filling bag body. The filling bag body is a rectangular flexible bag composed of two single-layer fabric surfaces 1 on the top and bottom and four double-layer fabric surfaces 2 on the front, back, left, and right sides, which can be filled with filling slurry. The two single-layer fabric surfaces 1 are made of flame-retardant and anti-static ventilation duct fabric. The outer fabric of the four double-layer fabric surfaces 2 is the same as that of the two single-layer fabric surfaces, but the inner fabric is a woven fabric with a semi-permeable membrane material as the support. The outer fabric of the double-layer fabric is slightly larger than the inner fabric to ensure that there are still gaps between the double fabrics after the semi-permeable membrane filling bag is filled with filling slurry for storing excess water. The specific size of the filling bag is determined according to the size of the goaf at the site.

[0033] In order to facilitate installation and prevent excess water from seeping out after the slurry fills the inside of the filling bag from being concentrated in the gaps at the bottom of the two layers of fabric, the inner and outer layers of fabric are sewn together. The sewing points 3 are arranged according to the vertices of a 1m×1m grid.

[0034] The filling bag body of the present invention is provided with fixing straps 4 evenly on each side. The fixing straps 4 are two strips of cloth sewn on the side of the filling bag body. They are used to fix the filling bag to the fixed anchor point 6 set in the goaf during the filling bag arrangement process. The distance between two adjacent fixing straps 4 and fixed anchor point 6 is controlled to be about 1m.

[0035] The four upper corners of the filling bag body of the present invention are respectively provided with grouting ports 5. The selection of grouting ports 5 during grouting is determined according to the height of the grouting ports 5 after the filling bag is arranged. The highest grouting port 5 among the four grouting ports 5 is selected for grouting of the filling pipe, and the second highest grouting port 5 among the four grouting ports 5 is selected for venting during the filling process. The remaining two grouting ports 5 are tied firmly to prevent grout leakage during the filling process.

[0036] Existing filling bags suffer from slurry segregation and bleeding during filling, resulting in a lower slurry concentration in the upper part of the filling body. This leads to significant shrinkage during subsequent solidification, resulting in poor topping performance. However, in the filling bag of this invention, the lower slurry concentration in the upper part due to segregation and bleeding allows excess water 8 from the slurry 7 to permeate through a semi-permeable membrane into the gaps between the double-layer fabric 2. Part of this water seeps back through the semi-permeable membrane into the lower, higher-concentration slurry 7, while the rest is stored in the gaps between the double-layer fabric 2. This stored water serves as a source of moisture for the hydration reaction during slurry solidification and also helps maintain the curing process of the filling body. Therefore, this invention effectively solves the problem of poor topping performance caused by slurry segregation.

[0037] The method for backfilling mining using the aforementioned semi-permeable membrane backfill bags specifically includes the following steps:

[0038] (1) When strip mining is adopted in the coal mine working face, the mining area to be mined will be divided into several strips in a certain direction according to the method of alternating between the reserved strip 9 and the mined strip 10. The reserved strip 9 plays the role of supporting the overlying rock above the mining area. When the working face completes the mining of one mined strip 10, while mining the second mined strip, the size of the first mined strip is measured, and filling bags are made according to the measured size of the mined strip. The design length of the filling bag is 40-60cm less than the actual length of the mined strip, and the design width of the filling bag is 40-60cm less than the actual width of the mined strip. This ensures that the gap between the outer surface of each filling bag and the surrounding rock of the mined strip is more than 20cm when the filling bags are arranged, which is used for water storage between the double-layer fabric.

[0039] (2) The prepared filling bags are transported to the underground working face through the mine's transportation system;

[0040] (3) Set up fixed anchor points 6 on each side of the goaf according to the position of the fixing straps 4 of the filling bag, and tie the fixing straps to the corresponding fixing anchor points;

[0041] (4) Measure the height of the four grouting ports 5 of the filling bags arranged in the goaf. Select the grouting port with the highest horizontal height among the four grouting ports for grouting the filling pipeline, and select the grouting port with the second highest horizontal height among the four grouting ports for venting during the filling process. Securely tie the remaining two grouting ports to prevent grout leakage during the filling process. Select the grouting port with the highest horizontal height for grouting to ensure that the filling grout can fill the rest of the filling bag first; select the grouting port with the second highest horizontal height for venting to ensure that the air in the filling bag can be discharged smoothly and that the filling grout can be pumped smoothly.

[0042] (5) After the above preparations are completed, the filling operation is started. The filling material is selected as cemented filling material. After the filling operation starts, the next goaf area can be operated in steps (1) to (4). After the filling bag is filled, the two untied grouting ports are tied first, and the next filling bag is filled.

[0043] (6) Due to the presence of the semi-permeable membrane, the excess water generated by the bleeding of the filling slurry is filtered into the gap between the two layers of fabric of the filling bag. Therefore, within 6-24 hours after the filling bag is filled, it is necessary to refill the filling bag through the previous grouting port to replenish the filling slurry that is missing due to the bleeding.

[0044] (7) When all the mining strips have been mined, or when the strength of the filling material in the filling bag is sufficient to support the overlying rock, the area after the filling material is filled is regarded as the reserved strip, and the previously reserved strips are mined in sequence.

Claims

1. A semi-permeable membrane filling bag for backfilling mining, characterized in that: The bag includes a flexible filling bag body, which is a rectangular flexible cloth bag that can be filled with filling slurry. The outer surface of the filling bag is evenly distributed with fixing straps. The slurry inlets of the filling bag are located at the four corners of the top of the filling bag. The top and bottom sides of the filling bag are made of single-layer flexible ventilation duct cloth, while the front, back, left, and right sides are made of double-layer cloth. The inner layer of the double-layer cloth is a cellulose semi-permeable membrane with textile fabric as the support, and the outer layer is flexible ventilation duct cloth. The two layers of cloth are sewn together at the vertices according to a 1m×1m grid, and the area of ​​the outer layer of the sewn double-layer cloth is slightly larger than the area of ​​the inner layer.

2. The semi-permeable membrane filling bag for filling mining according to claim 1, characterized in that: The outer layer of the flexible filling bag and the inner layer of the cellulose semi-permeable membrane are both made of antistatic and flame-retardant flexible fabric, which can be used in underground coal mining.

3. The semi-permeable membrane filling bag for filling mining according to claim 1, characterized in that: The distance between adjacent fixing straps on the outer surface of the flexible filling bag body is selected to be 90cm~110cm.

4. A method for strip backfilling mining, employing a semi-permeable membrane backfilling bag as described in any one of claims 1 to 3, characterized in that... Includes the following steps: (1) When the mine adopts the upward horizontal layered backfilling mining method for strip mining, the mining area is divided into two areas: the reserved strip and the extracted strip. The reserved strip plays the role of supporting the overlying rock above the mining area. When the working face completes the mining of one extracted strip, while mining the second extracted strip, the size of the first extracted strip is measured, and the backfilling bag is made according to the measured size of the extracted strip. (2) The prepared filling bags are transported to the underground working face through the mine's transportation system; (3) Set up fixed anchor points on each side of the goaf according to the position of the fixing straps of the filling bag, and tie the fixing straps to the corresponding fixing anchor points; (4) Measure the height of the four grouting ports of the filling bag that has been set up on site. Select the grouting port with the highest horizontal height among the four grouting ports for use in filling the pipeline grouting. Select the grouting port with the second highest horizontal height among the four grouting ports for venting during the filling process. Tie the other two grouting ports firmly to prevent grout leakage during the filling process. (5) After the above preparations are completed, the filling operation is started. The filling material is selected as cemented filling material. After the filling operation starts, the next goaf area can be operated in steps (1) to (4). After the filling bag is filled, the two untied grouting ports are tied first, and the next filling bag is filled. (6) Due to the presence of the semi-permeable membrane, the excess water generated by the bleeding of the filling slurry is filtered into the gap between the two layers of fabric of the filling bag. Therefore, within 6-24 hours after the filling bag is filled, the filling bag needs to be filled again to replenish the filling slurry that is missing due to the bleeding. (7) After the filling slurry is replenished, the secondary filling operation of the next filling bag is carried out.

5. The strip backfilling mining method according to claim 4, characterized in that: In step (1), the design length of the filling bag is 40-60cm shorter than the actual length of the extraction strip, and the design width of the filling bag is 40-60cm shorter than the actual width of the extraction strip. When the filling bags are arranged, the gap between each outer surface and the surrounding rock of the extraction strip is more than 20cm, which is used for water storage between the double-layer fabric.

6. The strip backfilling mining method according to claim 4, characterized in that: Grouting ports are set at the four corners of the filling bag. When the goaf is a sloping surface, the grouting port with the highest horizontal height is selected for grouting so that the filling slurry can fill the internal space of the filling bag first. The grouting port with the second highest horizontal height is selected for venting so that the air in the filling bag can be discharged smoothly and the filling slurry can be pumped smoothly.

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