Room-pillar goaf grouting filling and coal pillar re-mining method

Abstract

The invention discloses a room-pillar type goaf grouting filling and coal pillar re-mining method. The method comprises the following steps that 1, basic data of a target room-pillar type goaf are obtained; the basic information comprises coal seam burial depth, coal seam thickness, coal seam mining and retaining ratio and coal pillar distribution condition; 2, according to the basic data of the goaf, a filling station is established on the ground, a conveying pipeline is arranged, the reasonable drill hole interval is determined through a field test, vertical drill holes are formed to inject filling slurry into the goaf, and the goaf filling rate is determined through theoretical calculation and field exploration; and 3, arranging a conventional working face after the filling is compact, and recovering coal pillar resources by adopting a top coal caving operation method. According to the room and pillar type goaf grouting filling and coal pillar re-mining method, the coal resource recovery rate is increased, and potential safety hazards caused by mining of other coal seams are eliminated.

Description

Technical Field

[0001] This invention belongs to the field of coal resource recovery technology, specifically relating to a method for grouting and filling goaf in room-and-pillar goaf and coal pillar re-mining. Background Technology

[0002] Due to initial mine scale, technological limitations, and equipment issues, some mines in the Shanxi, Shaanxi, and Inner Mongolia regions of my country have long used room-and-pillar mining for coal seams. This resulted in a recovery rate far below current requirements, only around 30%. Consequently, a large number of coal pillars remain underground, creating stagnant coal reserves. The presence of these pillars not only leads to the loss and waste of high-quality coal resources, but also increases the risk of mine tremors, goaf fires, and the accumulation of toxic gases, severely impacting safe and efficient mine production. Summary of the Invention

[0003] The purpose of this invention is to provide a method for grouting and filling goaf in room-and-pillar mining and coal pillar re-mining, which improves the coal resource recovery rate and eliminates safety hazards for mining other coal seams.

[0004] The technical solution adopted in this invention is a method for grouting and backfilling of room-and-pillar goaf and coal pillar re-mining, comprising the following steps: Step 1: Obtain basic data of the target room-and-pillar goaf; basic data includes coal seam depth, coal seam thickness, coal seam retention ratio, and coal pillar distribution. Step 2: Based on the basic data of the goaf, establish a filling station on the ground and arrange the conveying pipeline. Determine the reasonable drilling spacing through field tests, arrange vertical boreholes to inject filling slurry into the goaf, and determine the goaf filling rate through theoretical calculations and field exploration. Step 3: After the filling and compaction are completed, a conventional working face is set up, and the top coal caving operation method is used to recover the coal pillar resources.

[0005] The invention is further characterized by: The process of obtaining basic information on the target room-and-pillar goaf in step 1 is as follows: collect original room-and-pillar goaf mining drawings, interview veteran miners from the original coal mine, and use borehole inspection and three-dimensional laser scanning to detect the old goaf.

[0006] In step 2, the filling slurry consists of aggregate, fly ash, cement, additives and water. The aggregate is selected from one or more of gangue, tailings or aeolian sand, and the aggregate particle size is less than 6mm.

[0007] The process of determining the borehole spacing in step 2 is as follows: Select a small section of the goaf as the test area, arrange relatively dense boreholes, and grout in the boreholes near the edge of the test area. Use other boreholes to explore the grout distribution range and determine the maximum flow distance. Then, use the borehole at the farthest diffusion range to perform a second grouting and use the borehole between the two grouting holes to explore the grouting situation. If it is not full, use the middle borehole to perform grouting again. Repeat this process until the entire goaf is filled, and finally obtain a reasonable borehole spacing.

[0008] Exploration was conducted using in-hole television technology.

[0009] The theoretical calculation in step 2 specifically involves determining the goaf filling rate by comparing the goaf space with the amount of filling slurry already injected.

[0010] Step 2 involves determining the goaf filling rate through on-site exploration: using transient electromagnetic detection technology to determine the goaf filling rate.

[0011] In step 3, when setting up a conventional working face, the working face roadway is arranged along the floor. If the top is a backfill body, then no top coal is vented during the coal pillar recovery process using the top coal caving operation method.

[0012] In step 3, when the top coal caving operation method is used to recover coal pillar resources, during the mining process of the working face, a unloader is installed above the main conveyor belt and a gangue conveyor belt is connected below. When the backfill body is mined, the unloader is opened so that the mined backfill body enters the gangue disposal site.

[0013] The beneficial effects of this invention are: The method for grouting and backfilling of room-and-pillar goaf and coal pillar re-mining provided by this invention increases the fluidity of the backfill slurry by designing small-diameter aggregates (less than 6mm), thereby reducing the number of boreholes and lowering economic costs. It proposes methods for determining the optimal borehole spacing and backfilling effect, ensuring dense backfilling of the goaf and providing safety guarantees for subsequent mining operations. It also proposes a method for arranging the working face roadway along the floor, effectively avoiding side spalling problems. The proposed methods of partially avoiding top coal release and installing unloaders on the main conveyor belt effectively reduce the content of backfill material in the coal, significantly reducing the difficulty of subsequent raw coal washing. By grouting and backfilling the room-and-pillar goaf, it eliminates various safety hazards in the goaf, improves coal resource recovery rate, and eliminates the stress concentration risk associated with mining lower-layer coal in the room-and-pillar goaf. Attached Figure Description

[0014] Figure 1 This is a flowchart of the method for grouting and filling goaf and coal pillar re-mining of the present invention. Detailed Implementation

[0015] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0016] Example 1 The method for grouting and filling goaf and re-mining of coal pillars proposed in this embodiment is as follows: Figure 1 As shown, it includes the following steps: Step 1: Obtain basic data of the target room-and-pillar goaf; basic data includes coal seam depth, coal seam thickness, coal seam retention ratio, and coal pillar distribution. Step 2: Based on the basic data of the goaf, establish a filling station on the ground and arrange the conveying pipeline. Determine the reasonable drilling spacing through field tests, arrange vertical boreholes to inject filling slurry into the goaf, and determine the goaf filling rate through theoretical calculations and field exploration. Step 3: After the filling and compaction are completed, a conventional working face is set up, and the top coal caving operation method is used to recover the coal pillar resources.

[0017] Example 2 The method for grouting and filling goaf and re-mining of coal pillars proposed in this embodiment is as follows: Figure 1 As shown, it includes the following steps: Step 1: Obtain basic data of the target room-and-pillar goaf; basic data includes coal seam depth, coal seam thickness, coal seam retention ratio, and coal pillar distribution. The process of obtaining basic information on the target room-and-pillar goaf in step 1 is as follows: collect original room-and-pillar goaf mining drawings, interview veteran miners from the original coal mine, and use borehole inspection and three-dimensional laser scanning to detect the old goaf. Step 2: Based on the basic data of the goaf, establish a filling station on the ground and arrange the conveying pipeline. Determine the reasonable drilling spacing through field tests, arrange vertical boreholes to inject filling slurry into the goaf, and determine the goaf filling rate through theoretical calculations and field exploration. Step 3: After the filling and compaction are completed, a conventional working face is set up, and the top coal caving operation method is used to recover the coal pillar resources.

[0018] Example 3 The method for grouting and filling goaf and re-mining of coal pillars proposed in this embodiment is as follows: Figure 1 As shown, it includes the following steps: Step 1: Obtain basic data of the target room-and-pillar goaf; basic data includes coal seam depth, coal seam thickness, coal seam retention ratio, and coal pillar distribution. The process of obtaining basic information on the target room-and-pillar goaf in step 1 is as follows: collect original room-and-pillar goaf mining drawings, interview veteran miners from the original coal mine, and use borehole inspection and three-dimensional laser scanning to detect the old goaf. Step 2: Based on the basic data of the goaf, establish a filling station on the ground and arrange the conveying pipeline. Determine the reasonable drilling spacing through field tests, arrange vertical boreholes to inject filling slurry into the goaf, and determine the goaf filling rate through theoretical calculations and field exploration. In step 2, the filling slurry consists of aggregate, fly ash, cement, additives and water. The aggregate is selected from one or more of gangue, tailings or aeolian sand, and the aggregate particle size is less than 6mm. Step 3: After the filling and compaction are completed, a conventional working face is set up, and the top coal caving operation method is used to recover the coal pillar resources.

[0019] Example 4 The method for grouting and filling goaf and re-mining of coal pillars proposed in this embodiment is as follows: Figure 1 As shown, it includes the following steps: Step 1: Obtain basic data of the target room-and-pillar goaf; basic data includes coal seam depth, coal seam thickness, coal seam retention ratio, and coal pillar distribution. The process of obtaining basic information on the target room-and-pillar goaf in step 1 is as follows: collect original room-and-pillar goaf mining drawings, interview veteran miners from the original coal mine, and use borehole inspection and three-dimensional laser scanning to detect the old goaf. Step 2: Based on the basic data of the goaf, establish a filling station on the ground and arrange the conveying pipeline. Determine the reasonable drilling spacing through field tests, arrange vertical boreholes to inject filling slurry into the goaf, and determine the goaf filling rate through theoretical calculations and field exploration. In step 2, the filling slurry consists of aggregate, fly ash, cement, additives and water. The aggregate is selected from one or more of gangue, tailings or aeolian sand, and the aggregate particle size is less than 6mm. The process of determining the borehole spacing in step 2 is as follows: Select a small section of room-and-pillar goaf as the test area, arrange relatively dense boreholes, grouting is carried out in the boreholes near the edge of the test area, and the distribution range of grout is explored using other boreholes. After determining the maximum flow distance, a second grouting is carried out using the borehole at the farthest diffusion range, and the grouting situation is explored using the borehole between the two grouting holes. If it is not full, grouting is carried out again using the middle borehole. This cycle is repeated until the entire goaf is filled, and finally a reasonable borehole spacing is obtained. Step 3: After the filling and compaction are completed, a conventional working face is set up, and the top coal caving operation method is used to recover the coal pillar resources.

[0020] Example 5 The method for grouting and filling goaf and re-mining of coal pillars proposed in this embodiment is as follows: Figure 1 As shown, it includes the following steps: Step 1: Obtain basic data of the target room-and-pillar goaf; basic data includes coal seam depth, coal seam thickness, coal seam retention ratio, and coal pillar distribution. The process of obtaining basic information on the target room-and-pillar goaf in step 1 is as follows: collect original room-and-pillar goaf mining drawings, interview veteran miners from the original coal mine, and use borehole inspection and three-dimensional laser scanning to detect the old goaf. Step 2: Based on the basic data of the goaf, establish a filling station on the ground and arrange the conveying pipeline. Determine the reasonable drilling spacing through field tests, arrange vertical boreholes to inject filling slurry into the goaf, and determine the goaf filling rate through theoretical calculations and field exploration. In step 2, the filling slurry consists of aggregate, fly ash, cement, additives and water. The aggregate is selected from one or more of gangue, tailings or aeolian sand, and the aggregate particle size is less than 6mm. The process of determining the borehole spacing in step 2 is as follows: Select a small section of room-and-pillar goaf as the test area, arrange relatively dense boreholes, grouting is carried out in the boreholes near the edge of the test area, and the distribution range of grout is explored using other boreholes. After determining the maximum flow distance, a second grouting is carried out using the borehole at the farthest diffusion range, and the grouting situation is explored using the borehole between the two grouting holes. If it is not full, grouting is carried out again using the middle borehole. This cycle is repeated until the entire goaf is filled, and finally a reasonable borehole spacing is obtained. Exploration was conducted using in-hole television technology; Step 3: After the filling and compaction are completed, a conventional working face is set up, and the top coal caving operation method is used to recover the coal pillar resources.

[0021] Example 6 The method for grouting and filling goaf and re-mining of coal pillars proposed in this embodiment is as follows: Figure 1 As shown, it includes the following steps: Step 1: Obtain basic data of the target room-and-pillar goaf; basic data includes coal seam depth, coal seam thickness, coal seam retention ratio, and coal pillar distribution. The process of obtaining basic information on the target room-and-pillar goaf in step 1 is as follows: collect original room-and-pillar goaf mining drawings, interview veteran miners from the original coal mine, and use borehole inspection and three-dimensional laser scanning to detect the old goaf. Step 2: Based on the basic data of the goaf, establish a filling station on the ground and arrange the conveying pipeline. Determine the reasonable drilling spacing through field tests, arrange vertical boreholes to inject filling slurry into the goaf, and determine the goaf filling rate through theoretical calculations and field exploration. In step 2, the filling slurry consists of aggregate, fly ash, cement, additives and water. The aggregate is selected from one or more of gangue, tailings or aeolian sand, and the aggregate particle size is less than 6mm. The process of determining the borehole spacing in step 2 is as follows: Select a small section of room-and-pillar goaf as the test area, arrange relatively dense boreholes, grouting is carried out in the boreholes near the edge of the test area, and the distribution range of grout is explored using other boreholes. After determining the maximum flow distance, a second grouting is carried out using the borehole at the farthest diffusion range, and the grouting situation is explored using the borehole between the two grouting holes. If it is not full, grouting is carried out again using the middle borehole. This cycle is repeated until the entire goaf is filled, and finally a reasonable borehole spacing is obtained. Exploration was conducted using in-hole television technology; The theoretical calculation in step 2 specifically involves determining the goaf filling rate by comparing the goaf space with the amount of filling slurry already injected. Step 3: After the filling and compaction are completed, a conventional working face is set up, and the top coal caving operation method is used to recover the coal pillar resources.

[0022] Example 7 The method for grouting and filling goaf and re-mining of coal pillars proposed in this embodiment is as follows: Figure 1 As shown, it includes the following steps: Step 1: Obtain basic data of the target room-and-pillar goaf; basic data includes coal seam depth, coal seam thickness, coal seam retention ratio, and coal pillar distribution. The process of obtaining basic information on the target room-and-pillar goaf in step 1 is as follows: collect original room-and-pillar goaf mining drawings, interview veteran miners from the original coal mine, and use borehole inspection and three-dimensional laser scanning to detect the old goaf. Step 2: Based on the basic data of the goaf, establish a filling station on the ground and arrange the conveying pipeline. Determine the reasonable drilling spacing through field tests, arrange vertical boreholes to inject filling slurry into the goaf, and determine the goaf filling rate through theoretical calculations and field exploration. In step 2, the filling slurry consists of aggregate, fly ash, cement, additives and water. The aggregate is selected from one or more of gangue, tailings or aeolian sand, and the aggregate particle size is less than 6mm. The process of determining the borehole spacing in step 2 is as follows: Select a small section of room-and-pillar goaf as the test area, arrange relatively dense boreholes, grouting is carried out in the boreholes near the edge of the test area, and the distribution range of grout is explored using other boreholes. After determining the maximum flow distance, a second grouting is carried out using the borehole at the farthest diffusion range, and the grouting situation is explored using the borehole between the two grouting holes. If it is not full, grouting is carried out again using the middle borehole. This cycle is repeated until the entire goaf is filled, and finally a reasonable borehole spacing is obtained. Exploration was conducted using in-hole television technology; The theoretical calculation in step 2 specifically involves determining the goaf filling rate by comparing the goaf space with the amount of filling slurry already injected. Step 2, which involves determining the goaf filling rate through on-site exploration, specifically involves using transient electromagnetic detection technology to determine the goaf filling rate. Step 3: After the filling and compaction are completed, a conventional working face is set up, and the top coal caving operation method is used to recover the coal pillar resources.

[0023] Example 8 The method for grouting and filling goaf and re-mining of coal pillars proposed in this embodiment is as follows: Figure 1 As shown, it includes the following steps: Step 1: Obtain basic data of the target room-and-pillar goaf; basic data includes coal seam depth, coal seam thickness, coal seam retention ratio, and coal pillar distribution. The process of obtaining basic information on the target room-and-pillar goaf in step 1 is as follows: collect original room-and-pillar goaf mining drawings, interview veteran miners from the original coal mine, and use borehole inspection and three-dimensional laser scanning to detect the old goaf. Step 2: Based on the basic data of the goaf, establish a filling station on the ground and arrange the conveying pipeline. Determine the reasonable drilling spacing through field tests, arrange vertical boreholes to inject filling slurry into the goaf, and determine the goaf filling rate through theoretical calculations and field exploration. In step 2, the filling slurry consists of aggregate, fly ash, cement, additives and water. The aggregate is selected from one or more of gangue, tailings or aeolian sand, and the aggregate particle size is less than 6mm. The process of determining the borehole spacing in step 2 is as follows: Select a small section of room-and-pillar goaf as the test area, arrange relatively dense boreholes, grouting is carried out in the boreholes near the edge of the test area, and the distribution range of grout is explored using other boreholes. After determining the maximum flow distance, a second grouting is carried out using the borehole at the farthest diffusion range, and the grouting situation is explored using the borehole between the two grouting holes. If it is not full, grouting is carried out again using the middle borehole. This cycle is repeated until the entire goaf is filled, and finally a reasonable borehole spacing is obtained. Exploration was conducted using in-hole television technology; The theoretical calculation in step 2 specifically involves determining the goaf filling rate by comparing the goaf space with the amount of filling slurry already injected. Step 2, which involves determining the goaf filling rate through on-site exploration, specifically involves using transient electromagnetic detection technology to determine the goaf filling rate. Step 3: After the backfilling and compaction are completed, a conventional working face is set up, and the top coal caving operation method is used to recover the coal pillar resources; In step 3, when setting up a conventional working face, the working face roadway is arranged along the floor. If the top is a backfill body, then no top coal is vented during the coal pillar recovery process using the top coal caving operation method.

[0024] Example 9 The method for grouting and filling goaf and re-mining of coal pillars proposed in this embodiment is as follows: Figure 1 As shown, it includes the following steps: Step 1: Obtain basic data of the target room-and-pillar goaf; basic data includes coal seam depth, coal seam thickness, coal seam retention ratio, and coal pillar distribution. The process of obtaining basic information on the target room-and-pillar goaf in step 1 is as follows: collect original room-and-pillar goaf mining drawings, interview veteran miners from the original coal mine, and use borehole inspection and three-dimensional laser scanning to detect the old goaf. Step 2: Based on the basic data of the goaf, establish a filling station on the ground and arrange the conveying pipeline. Determine the reasonable drilling spacing through field tests, arrange vertical boreholes to inject filling slurry into the goaf, and determine the goaf filling rate through theoretical calculations and field exploration. In step 2, the filling slurry consists of aggregate, fly ash, cement, additives and water. The aggregate is selected from one or more of gangue, tailings or aeolian sand, and the aggregate particle size is less than 6mm. The process of determining the borehole spacing in step 2 is as follows: Select a small section of room-and-pillar goaf as the test area, arrange relatively dense boreholes, grouting is carried out in the boreholes near the edge of the test area, and the distribution range of grout is explored using other boreholes. After determining the maximum flow distance, a second grouting is carried out using the borehole at the farthest diffusion range, and the grouting situation is explored using the borehole between the two grouting holes. If it is not full, grouting is carried out again using the middle borehole. This cycle is repeated until the entire goaf is filled, and finally a reasonable borehole spacing is obtained. Exploration was conducted using in-hole television technology; The theoretical calculation in step 2 specifically involves determining the goaf filling rate by comparing the goaf space with the amount of filling slurry already injected. Step 2, which involves determining the goaf filling rate through on-site exploration, specifically involves using transient electromagnetic detection technology to determine the goaf filling rate. Step 3: After the backfilling and compaction are completed, a conventional working face is set up, and the top coal caving operation method is used to recover the coal pillar resources; In step 3, when setting up a conventional working face, the working face roadway is arranged along the floor. If the top is a backfill body, then no top coal is released during the coal pillar recovery process using the top coal caving operation method. In step 3, when the top coal caving operation method is used to recover coal pillar resources, during the mining process of the working face, a unloader is installed above the main conveyor belt and a gangue conveyor belt is connected below. When the backfill body is mined, the unloader is opened so that the mined backfill body enters the gangue disposal site.

[0025] Example 10 Taking a certain coal mine as an example, its upper coal seam was initially mined by small coal mines using room-and-pillar mining methods, leaving a large amount of coal pillar resources in the goaf. This not only wastes coal resources, but also poses a stress concentration risk when mining the lower coal seam. The present invention aims to remine the coal pillar resources left in the old goaf in this area, specifically including the following steps: Step 1: Collect original room-and-pillar goaf mining drawings and data, interview veteran miners from the original coal mine, and use methods such as borehole inspection and 3D laser scanning to explore the old goaf. Obtain basic information about the target room-and-pillar goaf, specifically including coal seam depth, coal seam thickness, coal seam retention ratio, and coal pillar distribution.

[0026] Step 2: Conduct backfill slurry mix ratio tests (slump, mechanical property tests) to obtain the optimal backfill material mix ratio. Based on the backfill material, establish a ground backfilling station and arrange delivery pipelines. Determine the reasonable borehole spacing through field tests, arrange vertical boreholes to inject backfill slurry into the goaf, and determine the goaf filling rate through theoretical calculations and field exploration.

[0027] Step 3: After the backfill is compacted, a conventional working face is set up, and the top coal caving method is used to recover the coal pillar. If the top is a backfill, the top coal is not caved. At the same time, a unloader is installed above the main conveyor belt, and a gangue conveyor belt is connected below it. When the backfill is mined, the unloader is opened to allow the mined backfill to enter the gangue disposal site.

[0028] Ultimately, this will enable the safe and green remining of coal pillar resources in the goaf of the mine.

Claims

1. A method for grouting and backfilling of goaf in room-and-pillar type mining areas and re-mining of coal pillars, characterized in that, Includes the following steps: Step 1: Obtain basic data of the target room-pillar goaf; the basic data includes coal seam depth, coal seam thickness, coal seam retention ratio and coal pillar distribution. Step 2: Based on the basic data of the goaf, establish a filling station on the ground and arrange the conveying pipeline. Determine the reasonable drilling spacing through field tests, arrange vertical boreholes to inject filling slurry into the goaf, and determine the goaf filling rate through theoretical calculations and field exploration. Step 3: After the filling and compaction are completed, a conventional working face is set up, and the top coal caving operation method is used to recover the coal pillar resources.

2. The method for grouting and filling goaf and re-mining coal pillars according to claim 1, characterized in that, The process of obtaining basic information on the target room-and-pillar goaf in step 1 is as follows: collect original room-and-pillar goaf mining drawings, interview veteran miners from the original coal mine, and use borehole inspection and three-dimensional laser scanning to detect the old goaf.

3. The method for grouting and filling goaf and re-mining coal pillars according to claim 1, characterized in that, The filling slurry mentioned in step 2 is composed of aggregate, fly ash, cement, additives and water. The aggregate is selected from one or more of gangue, tailings or aeolian sand, and the particle size of the aggregate is less than 6 mm.

4. The method for grouting and filling goaf and re-mining coal pillars according to claim 1, characterized in that, The process of determining the borehole spacing in step 2 is as follows: Select a small section of room-and-pillar goaf as the test area, arrange relatively dense boreholes, and grout in the boreholes near the edge of the test area. Use other boreholes to explore the grout distribution range and determine the maximum flow distance. Then, use the borehole at the farthest diffusion range to perform a second grouting and use the borehole between the two grouting holes to explore the grouting situation. If it is not full, use the middle borehole to perform grouting again. Repeat this process until the entire goaf is filled, and finally obtain a reasonable borehole spacing.

5. The method for grouting and filling goaf and re-mining coal pillars according to claim 4, characterized in that, The exploration was conducted using in-hole television technology.

6. The method for grouting and filling goaf and re-mining coal pillars according to claim 1, characterized in that, The theoretical calculation in step 2 specifically involves determining the goaf filling rate by comparing the goaf space with the amount of filling slurry already injected.

7. The method for grouting and filling goaf and re-mining of coal pillars according to claim 1, characterized in that, The specific steps for determining the goaf filling rate in step 2 are as follows: using transient electromagnetic detection technology to determine the goaf filling rate.

8. The method for grouting and filling goaf and re-mining coal pillars according to claim 1, characterized in that, In step 3, when arranging the conventional working face, the working face roadway is arranged along the floor. During the coal pillar recovery process using the top coal caving operation method, if the top is a backfill body, then the top coal is not caved.

9. The method for grouting and filling goaf and re-mining coal pillars according to claim 1, characterized in that, In step 3, when the top coal caving operation method is used to recover coal pillar resources, during the mining process of the working face, a unloader is installed above the main conveyor belt and a gangue conveyor belt is connected below. When the backfill body is mined, the unloader is opened so that the mined backfill body enters the gangue disposal site.

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