Strip mine end slope coal pressing mining method based on end slope coal mining machine

Abstract

The invention discloses a strip mine end slope coal pressing mining method based on an end slope coal mining machine, which comprises the following steps: adjusting the height of all to-be-mined end slope coal steps, dividing the end slope coal steps into a plurality of unit sections, forming a mining chamber after mining, and carrying out composite filling on the mining chamber, the filling process is divided into a bottom anti-skid filling layer, a middle interval filling layer, a top hardening filling layer and a surface filling layer from bottom to top, along with continuous mining of the lowest layer of end slope coal step, lagging mining of the second layer of end slope coal step, and the like, mining of the third layer of end slope coal step to the last layer of end slope coal step is started in good time, and in the mining process, the end slope coal step is filled. And the dumping site follows and advances to normally dump soil. A stable standing platform is provided for an end slope coal mining machine adopting a rectangular frame to be grounded under the collective action of all filling layers, more than 60% of end slope coal can be mined through the overall scheme, mining equipment is mature, the mining process is linked with the strip mine production process, and normal production and dumping of the strip mine are not affected.

Description

Technical Field

[0001] This invention relates to a method for mining coal under end-side pressure, specifically to a method for mining coal under end-side pressure in open-pit mines based on an end-side coal mining machine. Background Technology

[0002] Open-pit coal mining with sidewall pressing features high resource recovery rates and significant economic and cost advantages, effectively extending the mine's service life, ensuring production continuity, avoiding resource waste and capacity interruption, and meeting current requirements for green mining and ecological protection. Sidewall mining machines, as an important method of sidewall pressing, are widely applicable and highly efficient. However, for layered sidewall coal mining, after the lower coal seam is mined, the goaf needs to be backfilled or filled. While using high-strength backfill materials can effectively ensure backfill strength, the cost is enormous. If ordinary materials are used for backfilling, the resulting foundation is relatively weak, easily causing instability, tilting, or even collapse of the mining machine and transportation system when mining the upper coal seam. Taking two common types of end-side coal mining machines as examples: one is a rectangular frame grounded type, and the other is a four-track supported type. The rectangular frame grounded type experiences significant local ground pressure during mining; the four-track supported type requires drilling holes under the two front tracks to insert anchor bolts for securing the equipment. If these anchor bolts are located in soft areas, it severely impacts mining efficiency and safety. Therefore, this invention proposes an open-pit mine end-side coal mining method based on an end-side coal mining machine to solve these problems and fully leverage the advantages of end-side mining. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides an open-pit mine end-side coal mining method based on an end-side coal mining machine. This method is designed for end-side coal mining with rectangular frame grounding and track support grounding, ensuring filling effect while reducing filling cost and achieving high mining efficiency.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for open-pit coal mining with end-side pressing based on an end-side coal mining machine, comprising the following steps: The height of all end-side coal steps to be mined is adjusted by combining or splitting steps to a height suitable for the end-side coal mining machine. The end-side coal steps are divided into multiple unit sections, with the unit sections on two adjacent layers of end-side coal steps staggered. Each unit section is divided into a mining section and a coal pillar. The end-side coal steps are mined sequentially from the spoil heap to the mining area, layer by layer, and multiple unit sections can be mined simultaneously. After the mining section is completed, a mining chamber is formed, and the mining chamber is backfilled with composite materials. During the process of the end-side coal mining machine withdrawing from the deepest part of the mining chamber to the mining chamber opening, anti-slip pits are excavated at intervals on the bottom surface of the mining chamber, and then a bottom anti-slip backfill layer with a thickness of about 1 / 5 to 1 / 6 of the mining chamber height is filled at the bottom of the mining chamber. After the bottom anti-slip filling layer is filled, the middle interval filling layer is filled on the bottom anti-slip filling layer. The middle interval filling layer is filled with the mining pit in an alternating manner of backfill area and support area. The support area is located above the anti-slip pit, and the backfill area is located above the area between two adjacent anti-slip pits. Before filling the support area, multiple holes are drilled on the side walls of the mining pit in its area. Then, steel bars that run through the mining pit are inserted into the holes to form a steel mesh. The support area is then filled in conjunction with the steel mesh. After the middle interval filling layer is filled, the top hardened filling layer and the surface filling layer are filled from bottom to top on top of it, with the surface filling layer connected to the top surface of the mining tunnel. As the lowest end coal bench is continuously mined, the second end coal bench begins to be mined at least three unit sections behind the location of the mine shaft where the lowest end coal bench is being filled. The first unit section of the second end coal bench is then mined, and so on, until the third end coal bench is mined in due course until the last end coal bench. During the mining process, the spoil heap is advanced and spoils are disposed of normally.

[0005] Furthermore, the unit section is divided into a mining section and a coal pillar in a 3:2 ratio, and the width of the mining section does not exceed 30m.

[0006] Furthermore, at least two unit sections can be mined simultaneously. For end walls with a safety factor exceeding 1.5, up to five unit sections can be mined simultaneously. When multiple unit sections are mined simultaneously, at least one unit section must be spaced out in between.

[0007] Furthermore, the anti-slip pits are spaced 20-30m apart, and each anti-slip pit includes multiple rows of strip grooves excavated at intervals, with the strip grooves spaced 2-3m apart. The ratio of the length of the anti-slip pit to the distance between two anti-slip pits is less than 1:2.

[0008] Furthermore, the thickness of the bottom anti-slip filling layer is 1 / 5 to 1 / 6 of the mine height.

[0009] Furthermore, after the middle interval filling layer is filled, the height of its top surface from the top surface of the mining chamber is 1 / 5 to 1 / 6 of the mining chamber height.

[0010] Furthermore, after the top hardened filling layer is filled, it is 20-30cm high from the top surface of the mining chamber.

[0011] Furthermore, the bottom anti-slip filling layer is filled with high-strength and waterproof filling material, the backfill area is filled with mining stripping material, the support area is filled with high-strength filling material, the top hardened filling layer is filled with a hard and highly expansive material, and the surface filling layer is filled with high-strength crushed stone soil and gravelly soil.

[0012] Compared with existing technologies, the bottom anti-slip backfill layer of this invention ensures that the layer will not shift due to subsequent stress. Simultaneously, this layer has high filling strength and high shear strength, effectively sealing the lower layer and preventing water intrusion, thus ensuring the stability of the upper backfill material. The middle interval backfill layer provides high-strength support for the upper part of the mining tunnel while reducing the average backfilling cost. The top hardened backfill layer effectively compensates for the settlement deformation of the backfill material, and together with the support zone backfill, provides a stable base for the surface backfill layer above. The surface backfill layer prevents equipment tilting. After the entire composite backfilling is completed, for end-side coal mining machines using rectangular frame grounding, the collective action of each backfill layer provides a stable standing platform. The overall solution can mine over 60% of the end-side coal, offering good economic benefits. The mining equipment is mature, the mining process is seamlessly integrated with the open-pit mine production process, management is simple, and it does not affect normal open-pit mine production and spoil disposal. Attached Figure Description

[0013] Figure 1 This is a top view of the mining state of the present invention; Figure 2 This is a schematic diagram of the segment division of the end coal bench unit in this invention; Figure 3 This is a schematic diagram of the central intermittent filling layer structure in the mining tunnel of the present invention; Figure 4 for Figure 1 Schematic diagram of section AA; In the diagram: 1-End side; 2.1-Lowest end side coal bench; 2.2-Second end side coal bench; 2.3-Third end side coal bench; 3-Mining section; 3.1-Mining section under mining; 3.2-Mining section just finished and preparing for backfilling; 3.3-Mining section already backfilled; 3.4-Mining section to be mined; 4-Coal pillar; 5-Pit bottom; 6-Rollover area; 7-Bottom anti-sliding backfill layer; 8-Middle interval backfill layer; 8.1-Backfill area; 8.2-Support area; 9-Top hardened backfill layer; 10-Face backfill layer; 11-Anti-sliding pit; 12-Drill hole; 13-Reinforcing steel; 14-Mining area. Detailed Implementation

[0014] The invention will now be further described with reference to the accompanying drawings.

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] like Figures 1 to 4 As shown, the present invention provides a technical solution, comprising the following steps: According to the applicable height of the end-face coal mining machine, the height of all end-face coal steps to be mined is adjusted to a suitable height for the end-face coal mining machine by combining steps or splitting steps; for example Figure 2 As shown, the end-face coal bench is divided into multiple unit sections. The unit sections on adjacent end-face coal benches are staggered. Each unit section is divided into mining section 3 and coal pillar 4 in a 3:2 ratio. The wider section is mining section 3, with the width balancing mining efficiency and end-face stability. If the mining width is too narrow, the mining capacity of the end-face coal mining machine cannot be effectively utilized; if the width is too large, it can easily lead to bench instability. Generally, the width of mining section 3 does not exceed 30m. The narrower section is coal pillar 4, which is not mined but used as a support pillar. (For ease of display...) Figure 1 The ratio in the middle is not divided according to 3:2; the end coal bench is mined sequentially from bottom to top from the spoil heap 6 to the mining area 14. Under normal circumstances, at least two unit sections are mined at the same time. For end 1 with a safety factor of more than 1.5, a maximum of five unit sections can be mined at the same time. When multiple unit sections are mined at the same time, at least one unit section must be separated in between.

[0017] Simultaneous mining is to accelerate the mining progress, while intermittent mining is to reduce interference between mining operations and avoid causing significant disturbance to end wall 1, thus affecting its stability. Priority is given to mining section 3 on one side of the open-pit spoil heap 6, followed by a gradual transition to the stope 14 side. The aim is to complete mining and backfilling as quickly as possible so that spoil heap 6 can proceed synchronously, avoiding spoil shortages. For ease of illustration, Figure 1 The image shows only one mining section 3.1 that is currently being mined, one mining section 3.2 that has just finished being mined and is being prepared for backfilling, one mining section 3.3 that has been filled, and one planned mining section 3.4 that is yet to be mined.

[0018] First, at the bottom of the open-pit mine (5), near the lowest end-face coal bench (2.1) of the tailings yard (6), the end-face coal mining machine and conveyor are deployed in the first mining section (3) to mine the end-face coal. The mining height is the height of the end-face coal bench. If the mining tunnel is close to the coal seam floor, the bottom of the mining tunnel extends along the direction of the coal seam floor, and the top of the mining tunnel is horizontal. Otherwise, it extends horizontally along both the top and bottom of the mining tunnel. In particular, if there is a large amount of seepage water in the end-face coal seam, the floor maintains a horizontal slope of 3‰, with the lowest point near the bottom of the pit. The purpose is to allow the seepage water during the mining process to flow naturally to the bottom of the pit, avoiding interference with the mining.

[0019] like Figure 4 As shown, after the mining section 3 is completed, a mining chamber is formed. In order to provide a stable foundation for the mining of the upper end coal, the mining chamber needs to be backfilled. In order to ensure the support effect after backfilling and reduce backfilling costs, this invention performs composite backfilling on the mining chamber. The backfilling process is divided into bottom anti-sliding backfilling layer 7, middle interval backfilling layer 8, top hardened backfilling layer 9 and surface backfilling layer 10 from bottom to top.

[0020] To prevent relative displacement between the backfill material and the bottom plate of the mining chamber due to stress or settlement, which would affect stability, and to ensure the sealing of the backfill material and prevent the upper and lower layers of backfill from mixing and settling, anti-slip pits 11 are excavated at intervals on the bottom surface of the mining chamber after the end-side coal mining machine reaches the boundary and withdraws from the deepest part of the mining chamber to the opening. The intervals between anti-slip pits 11 are 20-30m. Each anti-slip pit 11 includes multiple rows of strip grooves excavated at intervals, with an interval of 2-3m between the strip grooves. The ratio of the length of each anti-slip pit 11 to the distance between two anti-slip pits 11 is less than 1:2. The lower the strength of the coal pillar 4 itself, the shorter the interval between anti-slip pits 11 and the more rows of strip grooves, mainly to ensure the stability after backfilling. Then, a bottom anti-slip backfill layer 7 with a thickness of about 1 / 5-1 / 6 of the mining chamber height is filled at the bottom of the mining chamber using high-strength and waterproof backfill material. The bottom anti-slip filling layer 7 extends deep into the anti-slip pit 11, ensuring that the layer will not shift due to later stress. At the same time, this layer has high filling strength and high shear strength, which can effectively seal the lower filling layer and prevent water intrusion, thus ensuring the stability of the filling material above it.

[0021] After the bottom anti-slip filling layer 7 is filled, the middle interval filling layer 8 is then filled on top of the bottom anti-slip filling layer 7, such as... Figure 3 and Figure 4As shown, the intermediate filling layer 8 extends from the deepest part of the mining pit to the pit opening, and is filled in the mining pit using an alternating backfill zone 8.1 and support zone 8.2. The backfill zone 8.1 is filled with stripped material from the mining area, preferably high-strength, low-compressibility, and non-disintegrating material when exposed to water, using a combination of large and small particle sizes to ensure compaction. The support zone 8.2 is filled with high-strength filling material. The support zone 8.2 is located above the anti-slip pit 11, and the backfill zone 8.1 is located above the area between two adjacent anti-slip pits 11. Before filling the support zone 8.2, multiple boreholes 12 are drilled corresponding to the side walls of the mining pit within its area. Then, steel bars 13 are inserted into the boreholes 12, forming a steel mesh. The support zone 8.2 is then filled in conjunction with the steel mesh. The filling material in the support zone 8.2, combined with the steel mesh, provides high-strength support above the mining pit after solidification.

[0022] After the middle interlayer filling layer 8 is filled, the height of its top surface from the top surface of the mining chamber is about 1 / 5 to 1 / 6 of the mining chamber height. The support zone 8.2 can provide high-strength support for the top of the mining chamber, and the backfill zone 8.1 has low filling cost, which reduces the average filling cost of the mining chamber.

[0023] After the intermediate intermittent filling layer 8 is filled, the top hardened filling layer 9 and the surface filling layer 10 are filled sequentially from bottom to top on top of it. The top hardened filling layer 9 is filled with a material with high hardness and strong expansion. After the top hardened filling layer 9 is filled, it is 20-30cm away from the top surface of the mining chamber. The expansion material can effectively compensate for the settlement deformation of the backfill material. Together with the filling of the support area 8.2, it can provide a stable foundation for the surface filling layer 10 above it. The surface filling layer 10 is filled with high-strength crushed stone soil and gravelly soil. The surface filling layer 10 is in contact with the top surface of the mining chamber. Later, the surface filling layer 10 will directly contact the bottom of the end-side coal mining machine above, which can prevent the equipment from tilting.

[0024] After the entire composite filling is completed, for end-side coal mining machines with rectangular frame grounding, a stable standing platform is provided under the collective action of each filling layer.

[0025] As the lowest end coal bench 2.1 is continuously mined, the second end coal bench 2.2 begins mining its first unit section at least three unit sections behind the location of the mine shaft being filled by the lowest end coal bench 2.1. This process continues until the third end coal bench 2.3 is started, and so on, until the last end coal bench. During the mining process, the spoil heap 6 advances and dumps spoil normally.

[0026] The unit sections on the two adjacent end-face coal benches are staggered, with the upper coal pillar 4 completely above the lower mining section 3, and two-thirds of the width of the upper mining section 3 extending above the lower coal pillar 4. This mutual compensation of the strength and deformation of the coal pillar 4 and the backfill section ensures the overall stability of the end-face 1. The upper mining section 3, located above the lower coal pillar 4, facilitates the excavation of anti-slip pits 11 during the upper backfilling process, ensuring the backfilling effect. Simultaneous mining of the upper and lower layers accelerates the mining progress of the end-face 1 and avoids compressing the waste disposal space. For tracked end-side coal mining machines, if the anchors driven into the ground are driven into the coal pillar 4, the coal pillar itself is relatively hard, ensuring the stability of the end-side coal mining machine. If they are driven into the backfill layer, or onto the support zone 8.2, the filling material has high strength, ensuring the stability of the end-side coal mining machine. When driven into the backfill zone 8.1, surrounded by the bottom anti-slip filling layer 7, the support zone 8.2, and the top hardened filling layer 9, the backfill zone 8.1 is difficult to displace, its strength is increased, and the stability of the end-side coal mining machine is guaranteed.

[0027] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0028] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any minor modifications, equivalent substitutions, and improvements made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for open-pit coal mining with end-side coal pressing based on an end-side coal mining machine, characterized in that, Includes the following steps: The height of all the end coal benches to be mined is adjusted to a height suitable for the end coal mining machine; the end coal benches are divided into multiple unit sections, and the unit sections on the two adjacent end coal benches are staggered. The unit sections are divided into mining sections (3) and coal pillars (4); the end coal benches are mined sequentially from the spoil heap (6) to the mining area (14) and from bottom to top. After the mining section (3) is mined, a mining chamber is formed, and the mining chamber is filled with composite filling. During the process of the end-side coal mining machine withdrawing from the deepest part of the mining chamber to the mining chamber opening, anti-slip pits (11) are excavated at intervals on the bottom surface of the mining chamber, and then the bottom anti-slip filling layer (7) is filled at the bottom of the mining chamber. After the bottom anti-slip filling layer (7) is filled, the middle interval filling layer (8) is filled on the bottom anti-slip filling layer (7). The middle interval filling layer (8) is filled in the mining pit in an alternating manner of backfill area (8.1) and support area (8.2). The support area (8.2) is located above the anti-slip pit (11), and the backfill area (8.1) is located above the area between two adjacent anti-slip pits (11). Before filling the support area (8.2), multiple boreholes (12) are drilled on the side walls of the mining pit in its area. Then, steel bars (13) that run through the mining pit are inserted into the boreholes (12) to form a steel mesh. The support area (8.2) is then filled in conjunction with the steel mesh. After the middle interval filling layer (8) is filled, the top hardened filling layer (9) and the surface filling layer (10) are filled from bottom to top on top of it, and the surface filling layer (10) is connected to the top surface of the mining tunnel. As the lowest end coal bench (2.1) is continuously mined, the second end coal bench (2.2) begins to be mined at least three unit sections behind the location of the mine shaft being filled by the lowest end coal bench (2.1). This process continues until the third end coal bench (2.3) is mined, and so on, until the last end coal bench. During the mining process, the spoil heap (6) is advanced and spoils soil normally.

2. The method for open-pit coal mining with end-side coal pressing based on an end-side coal mining machine according to claim 1, characterized in that, The unit section is divided into mining section (3) and coal pillar (4) in a ratio of 3:

2. The width of mining section (3) shall not exceed 30m.

3. The method for open-pit coal mining with end-side pressure based on an end-side coal mining machine according to claim 1, characterized in that, At least two unit sections are to be mined at the same time. For end walls (1) with a safety factor of more than 1.5, a maximum of five unit sections can be mined at the same time. When multiple unit sections are mined at the same time, at least one unit section must be separated in between.

4. The method for open-pit coal mining with end-side pressing based on an end-side coal mining machine according to claim 1, characterized in that, The anti-slip pits (11) are spaced 20-30m apart. Each anti-slip pit (11) includes multiple rows of strip grooves excavated at intervals. The strip grooves are spaced 2-3m apart. The length of each anti-slip pit (11) and the distance between two anti-slip pits (11) are less than 1:

2.

5. A method for open-pit coal mining with end-side coal pressing based on an end-side coal mining machine according to claim 1, characterized in that, The thickness of the bottom anti-slip filling layer (7) is 1 / 5 to 1 / 6 of the height of the mining tunnel.

6. The method for open-pit coal mining with end-side pressing based on an end-side coal mining machine according to claim 1, characterized in that, After the middle interval filling layer (8) is filled, the height of its top surface from the top surface of the mining chamber is 1 / 5 to 1 / 6 of the height of the mining chamber.

7. The method for open-pit coal mining with end-side pressure based on an end-side coal mining machine according to claim 1, characterized in that, After the top hardened filling layer (9) is filled, it is 20-30cm away from the top surface of the mining chamber.

8. A method for open-pit coal mining with end-side coal pressing based on an end-side coal mining machine according to claim 1, characterized in that, The bottom anti-slip filling layer (7) is filled with waterproof filling material, the backfill area (8.1) is filled with mining stripping material, the support area (8.2) is filled with high-strength filling material, the top hardened filling layer (9) is filled with expansion material, and the surface filling layer (10) is filled with crushed stone soil and gravelly soil.

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