Opposite down-dip slope strip mine mining method

Abstract

The invention discloses an opposite down-dip slope strip mine mining method. The method comprises five steps of open-off cut horizontal pushing, dragline downward digging, supporting bridge backfilling, two-way stripping row and working line recovery. According to the method, the mining direction is redesigned, stripping and coal mining are carried out at the same time, and the problems of insufficient equipment capacity, difficult management and insufficient dumping space caused by concentrated acceleration of downward digging and stripping in the original process are solved; the refuse dump is constructed again, the risks of landslide and the like caused by the large dip angle of the coal seam are avoided, the strip mine without internal discharge is adjusted to be capable of internal discharge, the goaf is fully utilized, and mining-discharge imbalance is avoided; the goaf is released step by step, the inner row follows up synchronously, and the safety risk caused by insufficient stripping objects due to one-time release of the goaf in the original process is avoided; according to the method, only the mining technology in the opposite inclined coal seam area is adjusted, other areas are not affected, and long-term production arrangement of a mine is not affected; original mine equipment personnel can meet the process requirements, and the mine cost is not increased.

Description

Technical Field

[0001] The invention relates to an open-pit mining method, in particular to an opposite down-slope open-pit mining method. Background Art

[0002] During the long-term geological movement of coal seams, it is very easy to form concave areas locally, thus presenting a geological structure with a dipping direction. When the open-pit mine is mining this area, if the advancing direction is parallel to the horizontal component of the concave tendency on one side, the dipping slope open-pit mine described in the present invention is formed. When the open-pit mine is mining this area, the following problems will arise. First, in the early stage of mining, due to the subsidence of the coal seam, in order to ensure the mining output, the open-pit mine needs to accelerate the advancement and excavation at the same time, resulting in a sudden increase in the stripping volume, insufficient equipment capacity, and increased mining costs in the short term. In addition, the stripping material cannot be discarded and needs to occupy the space of the external dump. Second, when the inclination angle of the coal seam is large, before the open-pit mine is dug to the lowest point of the coal seam, the stripping material is very easy to slide along the bottom plate of the coal seam, and there is no condition for internal drainage, resulting in the open-pit mine being unable to achieve internal drainage, further aggravating the mining-drainage imbalance. Third, after the open-pit mining exceeds the lowest point of the coal seam, the conditions for internal drainage are met, and the goaf is released at one time, but there is insufficient stripping material, resulting in the goaf being unable to be filled, affecting the safety of the mining area. Summary of the Invention

[0003] In response to the problems existing in the above-mentioned prior art, the present invention provides a method for open-pit mining on a slope that rationally utilizes the goaf and avoids mining and drainage imbalance while ensuring mining safety, without affecting the long-term production arrangements of the mine.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for mining an open pit mine on a slope that is inclined in the opposite direction, comprising five steps: cutting and pushing, digging with a dragline, backfilling a support bridge, bidirectional stripping and rowing, and restoring a working line; Cutting and pushing: Before the starting working line of the open-pit mine advances to the edge of the down-dip coal seam, the stripping material above the coal seam is stripped ahead along the starting advancing direction of the open-pit mine, forming a cutting groove with a length spanning the entire down-dip coal seam and the up-dip coal seam area; Dragline excavation: Use the dragline to dig and expand the cut slot horizontally. After digging to the lowest point of the coal seam depression, no further digging will be carried out. Only horizontal expansion will be carried out until the expanded pit bottom width reaches the minimum pit bottom width. Backfill support bridge: After the horizontally expanded pit bottom width reaches the minimum pit bottom width, the cut groove continues to be horizontally expanded to both sides, and the expanded and stripped materials are directly discharged to the center of the pit bottom to build a support bridge connecting the down-sloping coal seam and the up-sloping coal seam floor; Two-way stripping and drainage: During the backfilling of the support bridge, the stripping materials and coal seams within the down-dip coal seam and the up-dip coal seam will be excavated simultaneously, forming an open-pit mine bottom working line composed of a mixture of coal mining area and stripping area. At the same time, the support bridge is continuously raised and advanced along the pit bottom working line, thereby forming a pit bottom dump and eventually connecting to the starting dump. Working line recovery: When the bidirectional stripping row advances to the distance L from the starting end of the open pit, the bottom wall of the open pit above the horizontal coal seam behind the edge of the up-dip coal seam begins to expand toward the side of the starting direction of the open pit; When the bidirectional stripping and mining process reaches the starting end of the open-pit mine, the down-dip coal seam and the up-dip coal seam are completely mined, and a new stripping line, a new coal mining line, and a new dumping step in the open-pit mine are formed. After that, the new stripping line and the new coal mining line continue to be mined along the starting direction of the open-pit mine, and the new dumping step in the dump follows the process.

[0005] The open pit mining process and arrangement were restored to the state before the up-and-down dipping of the coal seams.

[0006] Furthermore, the bottom width of the eye cutting groove is B=2H*arctanβ+A; wherein H is the maximum depth of the down-sloping coal seam and the up-sloping coal seam relative to the horizontal coal seam, β is the maximum slope angle of the open-pit mine end, and A is the minimum width of the pit bottom.

[0007] Furthermore, in the two-way stripping and drainage step, when the height of the supporting bridge reaches the horizontal coal seam bottom plate position, the spoil dump close to the up-sloping coal seam side no longer extends toward the up-sloping coal seam side, but reserves the minimum pit bottom width distance at the bottom, and gradually forms a new spoil dump step according to the maximum slope angle of the open-pit mine spoil dump.

[0008] Furthermore, the support bridge is constructed by mixing stripping materials and solid waste. During the construction process, electrode tubes are installed, electrolytes are injected, and electrochemical modification is performed to form a high-strength anti-seepage bridge body.

[0009] Furthermore, the distance L in the working line recovery step is when the new stripping working line and the new coal mining working line of the open pit mine are completed and the coal resources within the distance L have just been mined.

[0010] Compared with the existing technology, the present invention redesigns the mining direction to realize stripping and mining at the same time, avoiding the problems of insufficient equipment capacity, management difficulties and insufficient dumping space caused by the need for concentrated accelerated digging and stripping in the original process; the dumping yard is rebuilt to avoid the risks of landslides and other risks caused by the large inclination of the coal seam, and the open-pit mine that does not have internal drainage is adjusted to have internal drainage, making full use of the goaf and avoiding mining-drainage imbalance; the goaf is gradually released and the internal drainage follows up synchronously, avoiding the safety risks caused by the one-time release of the goaf and insufficient stripping in the original process; the present invention only adjusts the mining process in the opposite inclined coal seam area, but has no impact on other areas and does not affect the long-term production arrangements of the mine; the mine's original equipment and personnel can meet the process requirements without increasing the mine cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram of coal seam distribution according to the present invention; Figure 2 This is a schematic diagram of the eyelet groove arrangement of the present invention; Figure 3 This is a schematic diagram of the dragline digging of the present invention; Figure 4 This is a schematic diagram of the backfill support bridge and bidirectional stripping row of the present invention; Figure 5 This is a schematic diagram of the working line recovery of the present invention; In the figure: 1-downward-dipping coal seam; 2-upward-dipping coal seam; 3-horizontal coal seam; 4-edge of the downward-dipping coal seam; 5-edge of the upward-dipping coal seam; 6-starting working line; 7-central axis of the working line; 8-starting advancing direction; 9-stripping material; 10-eye cutting groove; 11-support bridge; 12-pit bottom working line; 13-pit bottom end wall; 14-starting end wall; 15-new advancing direction; 16-pit bottom spoil dump; 17-starting spoil dump; 18-new spoil dump step; 19-new stripping working line; 20-new coal mining working line. DETAILED DESCRIPTION

[0012] The present invention will be further described below with reference to the accompanying drawings.

[0013] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0014] like Figures 1 to 5 As shown, the present invention provides a technical solution, including five steps: cutting and pushing, dragline digging, backfilling support bridge, bidirectional stripping and mining, and working line recovery. Figure 1As shown in the figure, according to the contact time between the initial advancement direction 8 of the open-pit mine and the concave coal seam, the inclined coal seam first encountered by the open-pit mine is called the down-dip coal seam 1, the inclined coal seam encountered subsequently is called the up-dip coal seam 2, the non-concave coal seam connected to the down-dip coal seam 1 and the up-dip coal seam 2 is called the horizontal coal seam 3, the junction between the down-dip coal seam 1 and the horizontal coal seam 3 is called the down-dip coal seam edge 4, and the junction between the up-dip coal seam 2 and the horizontal coal seam 3 is called the up-dip coal seam edge 5.

[0015] Cut the eye and push it horizontally: Figure 2 As shown, the starting working line 6 of the open-pit mine advances to the edge 4 of the down-dip coal seam, and with the central axis 7 of the working line as the axis, the stripping material 9 above the coal seam is stripped in advance along the starting advancing direction 8 of the open-pit mine, forming a cutting groove 10 with a length spanning the entire down-dip coal seam 1 and the up-dip coal seam 2 area; the bottom width of the cutting groove 10 is B=2H*arctanβ+A; where H is the maximum depth of the down-dip coal seam 1 and the up-dip coal seam 2 relative to the horizontal coal seam 3, β is the maximum slope angle of the open-pit mine end wall, and A is the minimum width of the pit bottom, which varies depending on the equipment used in the open-pit mine and is generally 30-50m.

[0016] Dragline digging: Figure 3 As shown, the dragline shovel is convenient for digging, and the cut eye groove 10 is dug down and horizontally expanded. The horizontal expansion direction is perpendicular to the starting advancement direction 8 of the open-pit mine. After the dragline shovel digs down to the lowest point of the coal seam depression, it stops digging and only expands horizontally on both sides until the expanded pit bottom width reaches the minimum pit bottom width.

[0017] Backfill support bridge: Figure 4 As shown, after the horizontally expanded pit bottom width reaches the minimum pit bottom width, the cutting groove 10 continues to be horizontally expanded to both sides, and the expanded and stripped materials are directly discharged to the center of the pit bottom to construct a support bridge 11 connecting the bottom plates of the downward coal seam 1 and the upward coal seam 2; the support bridge 11 has three functions: one is to construct connecting passages on both sides to facilitate the movement of equipment; the second is to form support for the bottom plates of the coal seams on both sides, simulating a pillar on the inclined surface to prevent the slope from sliding; the third is that the support bridge 11 will serve as the starting point of the subsequent spoil dump.

[0018] Two-way stripping: Figure 4As shown, during the backfilling of the supporting bridge, the stripping materials and coal seams within the range of the down-dip coal seam 1 and the up-dip coal seam 2 will be excavated simultaneously to form an open-pit mine bottom working line 12 composed of a mixture of the mining area and the stripping area. The edge 4 of the down-dip coal seam and the edge 5 of the up-dip coal seam are each changed into a pit bottom end wall 13, and the starting end walls 14 of the open-pit mines on both sides are each changed into an open-pit mine bottom working line 12; the new advancement direction 15 of the open-pit mine is changed to a direction perpendicular to the starting advancement direction 8; at the same time, the supporting bridge 11 is continuously raised and advances with the pit bottom working line 12, thereby forming a pit bottom dump 16, and finally connecting with the starting dump 17; when the height of the supporting bridge 11 reaches the bottom plate position of the horizontal coal seam 3, the dump close to the up-dip coal seam 2 side no longer extends to the up-dip coal seam 2 side, but reserves the minimum pit bottom width distance at the bottom, and gradually forms a new dumping step 18 of the dump according to the maximum slope angle of the open-pit mine dump. In view of the low strength of southern mudstone stripping materials, the support bridge 11 can be constructed by mixing the stripping materials with solid waste. During the construction process, electrode tubes are installed, electrolytes are injected, and electrochemical modification is performed to form a high-strength anti-seepage bridge body. On the one hand, it can strengthen the support, and on the other hand, it can effectively prevent groundwater from infiltrating and affecting the initial support bridge strength.

[0019] As the backfilling of the support bridge 11 continues, the pit bottom working line 12 continues to advance in both directions along the new advancement direction 15 of the open-pit mine. The stripping materials within the down-dip coal seam 1 and the up-dip coal seam 2 are continuously excavated, and the coal resources therein are continuously mined.

[0020] Work line recovery: Figure 5 As shown, when the bidirectional stripping row advances to a distance of 14 L from the starting end wall of the open-pit mine, the bottom wall 13 of the open-pit mine above the horizontal coal seam 3 behind the edge 5 of the up-dip coal seam begins to expand toward the side of the starting advancement direction 8 of the open-pit mine and gradually forms a new stripping working line 19 of the open-pit mine and a new coal mining working line 20; in order to achieve a perfect continuation of open-pit mine production, it should be ensured that when the coal resources at a distance of L are mined, the new stripping working line 19 and the new coal mining working line 20 of the open-pit mine are just completed.

[0021] When the bidirectional stripping and mining reaches the starting end wall 14 of the open-pit mine, the down-dip coal seam 1 and the up-dip coal seam 2 are completely mined, and the new stripping working line 19, the new coal mining working line 20 and the new dumping step 18 of the spoil dump are formed in the open-pit mine. After that, the new stripping working line 19 and the new coal mining working line 20 continue to be mined along the starting advancement direction 8 of the open-pit mine, and the new dumping step 18 of the spoil dump follows the advancement. The open-pit mining technology and arrangement are restored to the state before passing the up-dip and down-dip coal seams.

[0022] 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 embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0023] 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 replacements, and improvements made to the above embodiments based on the technical essence of the present invention shall be included in the scope of protection of the technical solution of the present invention.

Claims

1. A method for mining open pit mines on opposite slopes, characterized in that: It includes five steps: cutting and pushing, dragline digging, backfilling the support bridge, two-way stripping and rowing, and working line restoration. Cutting and pushing: Before the open-pit mine starting working line (6) advances to the edge of the down-dip coal seam (4), the stripping material (9) above the coal seam is stripped ahead along the starting pushing direction (8) of the open-pit mine, forming a cutting groove (10) with a length spanning the entire down-dip coal seam (1) and the up-dip coal seam (2); Dragline excavation: using the dragline to dig down and horizontally expand the cut-eye groove (10), and after digging down to the lowest point of the coal seam depression, no further digging is carried out, and only horizontal expansion is carried out until the expanded pit bottom width reaches the minimum pit bottom width; Backfill support bridge: After the horizontally expanded pit bottom width reaches the minimum pit bottom width, the cut eye groove (10) is further expanded horizontally to both sides, and the expanded stripped materials are directly discharged to the center of the pit bottom to construct a support bridge (11) connecting the bottom plates of the down-sloping coal seam (1) and the up-sloping coal seam (2); Two-way stripping and drainage: During the backfilling of the support bridge, the stripping materials and coal seams within the down-dip coal seam (1) and the up-dip coal seam (2) are excavated simultaneously, forming an open pit bottom working line (12) composed of a mixture of the mining area and the stripping area. At the same time, the support bridge (11) is continuously raised and advanced along the pit bottom working line (12), thereby forming a pit bottom dump (16) and finally connecting with the starting dump (17); Working line recovery: When the bidirectional stripping row advances to the distance (14) L from the starting end of the open pit, the bottom end wall (13) of the open pit above the horizontal coal seam (3) behind the edge of the up-dip coal seam (5) begins to expand toward the side of the starting direction (8) of the open pit; When the bidirectional stripping and mining process advances to the starting end wall (14) of the open-pit mine, the down-dipping coal seam (1) and the up-dipping coal seam (2) are completely mined, and a new stripping working line (19) of the open-pit mine, a new coal mining working line (20), and a new dumping step (18) of the dumping yard are formed. Thereafter, the new stripping working line (19) and the new coal mining working line (20) continue to be mined along the starting advancement direction (8) of the open-pit mine, and the new dumping step (18) of the dumping yard follows the advancement; The open pit mining process and arrangement were restored to the state before the up-and-down dipping of the coal seams.

2. The method for mining an oppositely inclined slope open pit according to claim 1, characterized in that: The bottom width of the eye-cutting groove (10) is B=2H*arctanβ+A; wherein H is the maximum depth of the down-sloping coal seam (1) and the up-sloping coal seam (2) relative to the horizontal coal seam (3), β is the maximum slope angle of the open-pit mine end, and A is the minimum width of the pit bottom.

3. The method for mining an oppositely inclined slope open pit according to claim 1, characterized in that: In the bidirectional stripping and drainage step, when the height of the support bridge (11) reaches the bottom plate position of the horizontal coal seam (3), the dumping yard close to the up-sloping coal seam (2) no longer extends toward the up-sloping coal seam (2), but a minimum pit bottom width distance is reserved at the bottom, and a new dumping step (18) of the dumping yard is gradually formed according to the maximum slope angle of the open-pit mine dumping yard.

4. The method for mining an oppositely inclined slope open pit according to claim 3, characterized in that: The support bridge (11) is constructed by mixing stripping material and solid waste. During the construction process, electrode tubes are installed, electrolytes are injected, and electrochemical modification is performed to form a high-strength anti-seepage bridge body.

5. The method for mining an oppositely inclined slope open pit according to claim 1, characterized in that: The distance L in the working line recovery step is when the new stripping working line (19) and the new coal mining working line (20) of the open pit mine are completed and the coal resources at the distance L have just been mined.

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