A room-and-pillar high-water-content coal mining method

Abstract

This invention discloses a room-and-pillar high-water backfilling coal mining method. A main haulage roadway and a return air roadway are arranged at the upper boundary of the inclined mining block, and intake and return air inclined roadways are arranged at the two side boundaries respectively. Several connecting roadways are excavated from the end furthest from the main roadway to connect the two inclined roadways. The area between two adjacent connecting roadways forms a working face, which is divided into several rectangular coal rooms and U-shaped coal pillars. First, the coal rooms are mined using a tunneling machine. After mining, the goaf of the coal rooms is backfilled with high-water backfill material. After backfilling is completed, the coal rooms of the next working face are mined. After the backfill material stabilizes, the U-shaped coal pillars of the previous working face are mined back. After backfilling is completed, the goaf of the formed coal rooms and coal pillars is backfilled again, and so on, to complete the mining and backfilling operations of the entire mining block. This technology has the advantages of simple system layout, strong applicability, good backfilling and roof connection effect, and effective control of roof and overburden movement, providing a new technical method for "three-under" mining of inclined coal seams.

Description

Technical Field

[0001] This invention relates to the field of coal mining technology, and in particular to a room-and-pillar type high-water backfilling coal mining method. This invention is applicable to the safe and green mining of stagnant coal resources such as coal seams with dip angles of 3° to 15°, including coal under pressure from three sources and protective coal pillars. Background Technology

[0002] With the high-intensity mining of coal resources in my country and the large-scale development and utilization of coal resources in the west, my country's existing coal resources with excellent quality, simple occurrence, and superior mining technology are gradually shrinking. A large amount of coal resources under complex mining conditions, such as inclined coal seams, marginal coal seams, and residual coal seams, urgently need to be developed and utilized. However, inclined coal seams have complex geological structures, making traditional longwall mining difficult in terms of mining and support work, resulting in poor support stability and hindering the improvement of mining mechanization. Furthermore, due to the compression caused by tectonic movements, the roof and floor of inclined coal seams suffer greater damage than horizontal coal seams, with more developed bedding and primary fractures. Therefore, they are more prone to collapse under mining influences, leading to more intense overburden movement and more prominent ecological and environmental problems such as surface subsidence.

[0003] The coal industry development plan proposes to "promote green mining technologies such as backfilling mining, water-conserving mining, coal and gas co-mining, and gangue mining without shoveling to the surface, according to local conditions." Backfilling mining is a green mining technology that has been widely developed and applied in recent years, and it is an effective way to solve the problem of coal seam pressure from underground, coal seams, and other sources. Currently, traditional high-water backfilling mining mostly adopts longwall mining, which is not only suitable for coal seams with large dip angles, but also requires the deployment of coal mining machines, hydraulic supports, and other related equipment. This not only involves complex processes and huge investments, but also makes it difficult to control the immediate roof in a timely and effective manner, and the problem of tilting and sliding of supports, conveyors, and other equipment is very prominent. On the other hand, for coal seams with small dip angles, longwall high-water backfilling requires suspending backfill bags (bags) or deploying a large number of backfill baffles, which is not only cumbersome and complex in terms of labor organization, but also causes interference between backfilling and coal mining, resulting in low efficiency.

[0004] Therefore, researching a high-water backfilling mining technology that can ensure safe mining, is widely applicable to coal seams with different dip angles, and flexibly and conveniently backfill and recover stagnant coal resources such as coal pillars left underground, effectively control rock strata movement and surface deformation, has become a major technical challenge for the development of my country's coal industry, addressing the "three-under" coal pressure problem under inclined coal seam conditions. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a room-and-pillar type high-water backfilling coal mining method. This invention is safe, reliable, highly adaptable, and has a high resource recovery rate.

[0006] This invention is achieved through the following technical solution:

[0007] A method for high-water backfilling coal mining using a room-and-pillar system specifically includes the following steps:

[0008] a. At the upper boundary of the inclined mining block, excavate the main haulage roadway and return air roadway along the coal seam strike, and leave boundary protection coal pillars;

[0009] b. Starting from the return airway and transport airway on both sides, excavate the intake airway and return airway respectively along the coal seam dip to the lower boundary. At the lower boundary, excavate the connecting roadway. The two ends of the connecting roadway are connected to the intake airway and return airway respectively.

[0010] c. Excavate a second connecting roadway at a certain distance from the first connecting roadway, using a tunneling machine to excavate coal, a loader to load coal, and a trackless rubber-tired vehicle to transport coal. After the roadways are connected, temporary seals are set up at both ends.

[0011] d. The solid coal area between the two connecting roadways constitutes the first mining face, which is then divided into rectangular coal rooms and U-shaped coal pillars;

[0012] e. In the connecting roadway of the first mining face, the rectangular coal room is mined sequentially from the intake airway to the return airway, wherein the thickness of the coal pillar between the goaf of the rectangular coal room and the connecting roadway is [missing information]. L After mining is completed, a temporary seal should be set up at the exit of the goaf in the coal room in a timely manner.

[0013] f. When the rectangular coal room of the first mining face is completely mined, the second connecting roadway is temporarily sealed. At the same time, filling retaining walls are set up in the intake and return air inclined roadways near the entrance of the second connecting roadway to form a closed space.

[0014] g. By laying high-water filling pipelines, high-water filling material is simultaneously pumped into the enclosed space at the filling retaining wall positions in the two inclined tunnels to completely fill it;

[0015] h. After filling is completed, begin excavating the third connecting tunnel to form the second working face. Similarly, temporary seals are set at both ends of the excavated connecting tunnel.

[0016] i. The second working face coal chamber is mined in the same way. After the mining is completed, the compressive strength and deformation strength of the high-water filling material in the first working face reach the predetermined value. At this time, the remaining U-shaped coal pillars are mined, and temporary seals are set at the goaf exit of each U-shaped coal pillar.

[0017] j. When the rectangular coal room of the second working face and the U-shaped coal pillar of the first working face have been completely mined, the temporary sealing of the third connecting roadway is opened, and at the same time, filling retaining walls are set up in the intake and return air inclined roadways near the entrance of the third connecting roadway to form a closed space.

[0018] k. Through the high-water filling pipeline, high-water filling material is simultaneously pumped into the enclosed space at the filling retaining wall positions in the intake and return air inclined tunnels to completely fill the space.

[0019] l. Repeat steps c to k to complete the mining and backfilling work of all working faces in this block.

[0020] Coal pillar thickness between the goaf and the connecting roadway L It is determined based on the coal seam burial depth, coal strength, goaf size, and surrounding rock stability.

[0021] The filling process of the high-moisture filling material is as follows:

[0022] a) The working face is divided into several rectangular coal rooms and U-shaped coal pillars. Coal pillars are left between the rectangular coal rooms and the connecting roadway as natural retaining walls for high-water backfill material.

[0023] b) Filling and conveying pipelines are arranged simultaneously in the intake and return air inclined tunnels to carry out filling operations in a unified manner, ensuring that the flow rate and velocity of the two filling and conveying pipelines are the same.

[0024] The advantages of this invention are: Based on the traditional longwall high-water backfilling mining method, this invention proposes a room-and-pillar high-water backfilling mining technology to address the technical difficulties of backfilling mining under near-horizontal coal seam conditions. The system layout is simple, the construction period is short, and the coal output is fast. There is no need for complex support processes and special backfilling supports in the mining block, and no need for supporting longwall mining equipment, resulting in significant economic benefits. The "room first, pillar later, mining and backfilling cycle" mining method improves the coal output rate and production efficiency.

[0025] The room-and-pillar type high-water backfilling mining technology of this invention makes full use of the self-flow characteristics of high-water backfilling materials under near-horizontal and gently inclined coal seam conditions, reduces the labor intensity of the backfilling process, ensures the dense accumulation and complete roof contact of the backfilling body in the goaf, and the design of the U-shaped coal pillar avoids the process of suspending backfilling bags (bags) or laying a large number of backfilling baffles under near-horizontal coal seam conditions, thus reducing equipment investment.

[0026] This invention divides each working face within a mining block into several coal rooms and pillars. The "mining room with pillars, filling room with pillars" backfilling mining method effectively controls roof collapse and rock strata movement, improving the safety factor of mining. This technology, while achieving safe recovery of coal under pressure and other stagnant resources, maximizes coal recovery rate and effectively controls rock strata movement and surface deformation. It provides a novel technical model for efficient coal resource recovery and environmental protection in geologically complex mines in my country, possessing significant scientific and engineering implications and broad application prospects. Attached Figure Description

[0027] Figure 1 This is a plan view of the excavation of the connecting roadway at working face #2 of this invention;

[0028] Figure 2 This is a cross-sectional view of the excavation of the connecting roadway at the No. 2 working face of this invention;

[0029] Figure 3 This is a plan view of the filling of the goaf area in the No. 1 working face of the present invention;

[0030] Figure 4 This is a cross-sectional view of the filling of the goaf area in the No. 1 working face of this invention;

[0031] Figure 5 This is a plan view of the coal room mining at working face #2 of this invention;

[0032] Figure 6 This is a cross-sectional view of the coal seam mining at working face #2 of this invention;

[0033] Figure 7 This is a plan view of the coal pillar mining of the No. 1 working face of the present invention;

[0034] Figure 8 This is a cross-sectional view of the coal pillar mining at the No. 1 working face of this invention;

[0035] Figure 9 This is a plan view of the filling of the goaf area of ​​the No. 1 working face coal pillar and the goaf area of ​​the No. 2 working face coal room of the present invention;

[0036] Figure 10 This is a cross-sectional view of the filling of the goaf area of ​​the No. 1 working face and the goaf area of ​​the No. 2 working face in this invention;

[0037] Figure 11 This is a plan view showing that all working faces within the mining block of this invention have been fully mined and filled.

[0038] Figure 12 This is a cross-sectional view showing the complete mining and backfilling of all working faces within the mining block of this invention.

[0039] In the diagram: 1-Main transport roadway, 2-Return air roadway, 3-Boundary protection coal pillar, 4-Intake airway, 5-Return airway, 6-Connecting roadway, 7-Tunneling machine, 8-Loader, 9-Trackless rubber-tired vehicle, 10-Temporary sealing, 11-Filling retaining wall, 12-Filling conveying pipeline, 13-High water filling material. Detailed Implementation

[0040] A certain western mine has a mining area of ​​7.15 km². 2The coal seam has a strike length of 3.35 km and a dip length of 2.13 km. It exhibits a monocline structure with no major faults or folds. The dip angle ranges from 3 to 11°, with an average dip angle of 5°. The seam depth ranges from 245 to 470 m, and the coal seam is stable with an average thickness of 3.0 m. The mine's geological reserves are 24.13 Mt, and recoverable reserves are 15.72 Mt. Located in a suburban area, the mine has densely packed buildings and structures within its mining area. According to the "Specifications for the Retention of Coal Pillars and Coal Mining under the Influence of Buildings, Water Bodies, Railways and Main Shafts" and related regulations, effective measures are needed to protect the coalfield during mining to ensure safe and efficient recovery of coal resources while strictly controlling surface subsidence. To address these challenges, this patent describes a specific implementation method for room-and-pillar high-water backfill mining in the first mining block as follows:

[0041] (1) For the first mining block, the transport roadway 1 and return air roadway 2 are excavated along the coal seam at the upper boundary of the mining block. The width of the transport roadway 1 and return air roadway 2 is 5.5m. Boundary protection coal pillars 3 are left at the boundary of the block.

[0042] (2) Starting from the main roadway on both sides, the intake airway 4 and the return airway 5 are excavated along the coal seam dip to the lower boundary. At the lower boundary, the connecting roadway 6 of the 01# working face is excavated to connect the two roadways. The width of the roadways is 5.5m.

[0043] (3) Excavate the connecting roadway 6 of the 02# working face 40m away from the 01# working face connecting roadway. The same method is used: a tunneling machine 7 for excavation, a loader 8 for loading, and a trackless rubber-tired vehicle 9 for transporting coal. After the roadway is completed, temporary seals 10 are set at both ends. The temporary seals are made of tarpaulin and fixed with wire. Figure 1 , 2 As shown;

[0044] (4) At this point, the solid coal area between the two connecting roadways constitutes the first mining face. The working face is then divided into several 32m (length) x 10m (width) rectangular coal rooms and U-shaped coal pillars. The distance between two adjacent coal rooms is 10m, and the thickness of the coal pillar between the coal room and the connecting roadway is 8m.

[0045] (5) First, the coal room is mined in the connecting roadway of the 01# working face in the order from the intake inclined roadway 4 to the return inclined roadway 5. The tunneling machine 7 is used to mine the coal, the loader 8 is used to load the coal, and the trackless rubber-tired vehicle 9 is used to transport the coal. After the mining is completed, a temporary seal 10 is set up at the exit of the coal room goaf in a timely manner. The temporary seal 10 is fixed with tarpaulin and iron wire.

[0046] (6) When all the coal rooms of the 01# working face are mined, the temporary sealing 10 of the connecting roadway of the 02# working face is opened. At the same time, filling retaining walls 11 are arranged in the intake airway 4 and the return airway 5 near the port of the connecting roadway of the 02# working face to form a closed space. The filling retaining wall 11 is a reusable mechanical retaining wall.

[0047] (7) By laying high-water filling pipeline 12, high-water filling material 13 is simultaneously pumped into the enclosed space at the filling retaining wall 11 position in the two inclined tunnels to completely fill it, such as Figure 3 , 4 As shown;

[0048] (8) After the filling is completed, the 03# working face connecting roadway is excavated. After the excavation is completed, temporary sealing 10 is set at both ends, and the 02# working face mining area is formed at this time.

[0049] (9) The coal chamber of working face 02 is mined in the same manner. After the mining is completed, the compressive strength and deformation strength of the filling material in working face 01 reach the predetermined values. At this time, the remaining coal pillars are mined, and temporary sealing 10 is set at the exit of each coal pillar goaf. Figure 5-8 As shown;

[0050] (10) When the coal room of the 02# working face and the coal pillar of the 01# working face are all mined, the temporary sealing 10 of the connecting roadway of the 03# working face is opened, and at the same time, filling retaining walls 11 are set up in the two inclined roadways near the port of the connecting roadway of the 03# working face to form a closed space.

[0051] (11) Through the high-water filling pipeline 12, high-water filling material 13 is simultaneously pumped into the enclosed space at the filling retaining wall 11 position in both inclined tunnels to completely fill it, such as Figure 9-10 As shown;

[0052] Repeat steps 3 through 11 to complete the mining and backfilling work of all working faces within this block, such as... Figure 10-11 As shown.

[0053] Coal pillar thickness between the goaf and the connecting roadway L It is determined based on the coal seam burial depth, coal strength, goaf size, and surrounding rock stability.

[0054] The filling process of the high-moisture filling material 13 is as follows:

[0055] a) The working face is divided into several rectangular coal rooms and U-shaped coal pillars. Coal pillars are left between the rectangular coal rooms and the connecting roadway as natural retaining walls for high-water backfill material.

[0056] b) Filling and conveying pipelines 12 are arranged simultaneously in the intake air inclined tunnel 4 and the return air inclined tunnel 5 to carry out filling operations in a unified manner, ensuring that the flow rate and velocity of the two filling and conveying pipelines are the same.

Claims

1. A method for high-water backfilling coal mining using a room-and-pillar system, characterized in that: Specifically, the following steps are included: a. At the upper boundary of the inclined mining block, excavate the main haulage roadway (1) and return air roadway (2) along the coal seam strike, and leave boundary protection coal pillars (3). b. Starting from the return air roadway (2) and the transport roadway (1) on both sides, excavate the intake air roadway (4) and the return air roadway (5) respectively along the coal seam dip to the lower boundary. Then, excavate the connecting roadway (6) at the lower boundary. The two ends of the connecting roadway (6) are connected to the intake air roadway (4) and the return air roadway (5) respectively. c. Excavate the second connecting roadway (6) at a certain distance from the first connecting roadway (6), use a tunneling machine (7) to excavate coal, a loader (8) to load coal, and a trackless rubber-tired vehicle (9) to transport coal. After the roadways are connected, set up temporary seals (10) at both ends. d. The solid coal area between the two connecting roadways constitutes the first mining face, which is then divided into rectangular coal rooms and U-shaped coal pillars; e. In the connecting roadway of the first mining face, the rectangular coal room is mined sequentially from the intake inclined roadway (4) to the return inclined roadway (5), wherein the thickness of the coal pillar between the goaf of the rectangular coal room and the connecting roadway (6) is [missing information]. L After mining is completed, a temporary seal should be set up at the exit of the coal goaf in a timely manner (10). f. When all the rectangular coal rooms of the first mining face are mined, the second connecting roadway (6) is temporarily sealed (10), and filling retaining walls (11) are set up near the port of the second connecting roadway (6) in the intake airway (4) and return airway (5) respectively to form a closed space; g. By laying a high-water filling pipeline (12), high-water filling material (13) is pumped into the closed space at the location of the filling retaining wall (11) in the two inclined tunnels to fill it completely; h. After filling is completed, the third connecting roadway (6) is excavated to form the second working face. Temporary seals (10) are also set at both ends of the excavated connecting roadway. i. The second working face coal chamber is mined in the same way. After the mining is completed, the compressive strength and deformation strength of the high water filling material (13) in the first working face reach the predetermined value. At this time, the U-shaped coal pillars left behind are mined, and temporary sealing (10) is set at the goaf exit of each U-shaped coal pillar. j. When the rectangular coal room of the second working face and the U-shaped coal pillar of the first working face are all mined, the third connecting roadway (6) is temporarily sealed (10), and filling retaining walls (11) are set up in the intake airway (4) and return airway (5) near the port of the third connecting roadway (6) to form a closed space. k. Through the high water filling pipeline (12), high water filling material (13) is pumped into the closed space at the position of the filling retaining wall (11) in the intake air inclined tunnel (4) and the return air inclined tunnel (5) to completely fill it; l. Repeat steps c to k to complete the mining and backfilling work of all working faces in this block.

2. The method for high-water backfilling coal mining using a room-pillar system according to claim 1, characterized in that: Coal pillar thickness between the goaf and the connecting roadway L It is determined based on the coal seam burial depth, coal strength, goaf size, and surrounding rock stability.

3. The method for high-water backfilling coal mining using a room-pillar system according to claim 1, characterized in that: The filling process of the high-water filling material (13) is as follows: a) The working face is divided into several rectangular coal rooms and U-shaped coal pillars. Coal pillars are left between the rectangular coal rooms and the connecting roadway as natural retaining walls for high-water backfill material. b) Filling and conveying pipelines (12) are arranged simultaneously in the intake air inclined tunnel (4) and the return air inclined tunnel (5) to carry out filling operations in a unified manner, ensuring that the flow rate and velocity of the two filling and conveying pipelines are the same.

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