A method for open-pit mining on a dip-slope

Abstract

This invention discloses a method for open-pit mining on a dipping coal seam, comprising five steps: cutting and pushing the face, digging with a bucket shovel, backfilling the support bridge, bidirectional stripping and dumping, and restoring the working line. This invention redesigns the mining direction to achieve simultaneous stripping and mining, avoiding the problems of insufficient equipment capacity, management difficulties, and insufficient dumping space caused by the need for concentrated and accelerated stripping in the original process. It reconstructs the dumping ground, avoiding risks such as landslides caused by large coal seam dips, and transforms open-pit mines that previously lacked internal dumping into those capable of it, fully utilizing the goaf and avoiding mining-dumping imbalance. The goaf is released gradually, with internal dumping proceeding simultaneously, avoiding the safety risks caused by insufficient stripping material when the goaf is released all at once in the original process. This invention only adjusts the mining process within the dipping coal seam area, without affecting other areas, and does not disrupt the mine's long-term production schedule. The existing equipment and personnel can meet the process requirements without increasing mine costs.

Description

Technical Field

[0001] This invention relates to an open-pit mining method, specifically to an open-pit mining method for a dipping slope. Background Technology

[0002] During long-term geological movements, coal seams are prone to forming localized depressions, resulting in a dipping-side geological structure. When an open-pit mine excavates this area, if the direction of advancement is parallel to the horizontal component of the dipping slope on one side, a dipping-side open-pit mine, as described in this invention, is formed. The following problems arise when an open-pit mine excavates this area: First, in the early stages of mining, due to coal seam subsidence, to ensure production output, the open-pit mine needs to accelerate both advancement and excavation, leading to a surge in stripping volume, insufficient equipment capacity, increased short-term mining costs, and the inability to dispose of the stripped material, requiring the use of external spoil disposal space. Second, when the coal seam dip angle is large, before the open-pit mine excavates to the lowest point of the coal seam, the stripped material easily slides along the coal seam floor, lacking internal disposal conditions, further exacerbating the mining-disposal imbalance. Third, after the open-pit mine has excavated beyond the lowest point of the coal seam depression, internal disposal conditions are available, and the goaf is released all at once. However, insufficient stripped material prevents the goaf from being filled, affecting the safety of the mining area. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a method for open-pit mining on a dipping slope, which makes reasonable use of the goaf, avoids imbalance between mining and drainage while ensuring mining safety, and does not affect the long-term production schedule of the mine.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for open-pit mining on a dipping slope, comprising five steps: cutting and pushing the eye, digging with a bucket shovel, backfilling the support bridge, bidirectional stripping and drainage, and restoring the working line;

[0005] Cutting and pushing: Before the starting working line of the open-pit mine advances to the edge of the downward-dipping coal seam, the stripping material above the coal seam is stripped ahead of the starting advancing direction of the open-pit mine, with the central axis of the working line as the axis, forming a cutting groove with a length spanning the entire area of ​​the downward-dipping and upward-dipping coal seams;

[0006] Drag shovel excavation: The drag shovel is used to excavate and horizontally expand the cut groove. After excavating to the lowest point of the coal seam depression, no further excavation is carried out. Only horizontal expansion is carried out until the width of the expanded pit bottom reaches the minimum pit bottom width.

[0007] 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. The expanded stripped material is directly discharged to the center of the pit bottom to construct a support bridge connecting the bottom plate of the downward-dip coal seam and the bottom plate of the upward-dip coal seam.

[0008] Two-way stripping and dumping: During the backfilling of the support bridge, the stripping material and coal seam within the range of the downward and upward coal seams will be excavated simultaneously to form an open-pit mine bottom working line composed of a coal mining area and a stripping area. At the same time, the support bridge will be continuously raised and will advance along the pit bottom working line to form a pit bottom dumping site, which will eventually connect with the initial dumping site.

[0009] Working line restoration: When the bidirectional stripping and drainage advance reaches a distance L from the starting end of the open-pit mine, the bottom end of the open-pit mine above the horizontal coal seam after the edge of the up-dip coal seam begins to expand towards the side of the starting direction of the open-pit mine advance;

[0010] When the bidirectional stripping and dumping advances to the starting end of the open-pit mine, the downward-dip coal seam and the upward-dip coal seam are completely mined, and the new stripping working line, the new coal mining working line, and the new dumping platform of the dumping site are formed. Thereafter, the new stripping working line and the new coal mining working line continue to mine along the starting direction of the open-pit mine, and the new dumping platform of the dumping site follows the advance.

[0011] The open-pit mining process and arrangements have been restored to their state before the over-dip coal seams.

[0012] Furthermore, the bottom width of the cut groove is B = 2H * arctanβ + A; where H is the maximum depth of the downward-dip coal seam and the upward-dip coal seam relative to the horizontal coal seam, β is the maximum slope angle of the open-pit mine end face, and A is the minimum width of the pit bottom.

[0013] Furthermore, in the bidirectional stripping and dumping step, when the height of the support bridge reaches the position of the horizontal coal seam bottom plate, the dumping ground near the side of the upward-sloping coal seam no longer extends to the side of the upward-sloping coal seam, but instead reserves the minimum pit bottom width distance at the bottom, and gradually forms a new dumping ground step according to the maximum slope angle of the open-pit mine dumping ground.

[0014] Furthermore, the supporting bridge is constructed using a mixture of stripped material and solid waste. During the construction process, electrode tubes are installed, electrolytes are injected, and electrochemical modification is carried out to form a high-strength seepage-proof bridge body.

[0015] Furthermore, the distance L in the working line restoration 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 at distance L have just been mined.

[0016] Compared with existing technologies, this invention redesigns the mining direction to achieve simultaneous stripping and mining, avoiding the problems of insufficient equipment capacity, management difficulties, and insufficient waste dumping space caused by the need for concentrated and accelerated excavation and stripping in the original process. It also reconstructs the waste dump, avoiding risks such as landslides caused by steeply dipping coal seams, and transforming open-pit mines that previously lacked internal waste dumping into mines capable of it, fully utilizing the goaf and avoiding mining-drainage imbalance. The goaf is released gradually, with internal waste dumping following simultaneously, avoiding the safety risks associated with insufficient stripping material due to a one-time release of the goaf in the original process. This invention only adjusts the mining process within the opposing inclined coal seam area, without affecting other areas and thus not impacting the mine's long-term production arrangements. Existing mine equipment and personnel can meet the process requirements without increasing mine costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the coal seam distribution according to the present invention;

[0018] Figure 2 This is a schematic diagram of the eyelet arrangement of the present invention;

[0019] Figure 3 This is a schematic diagram of the excavation process of the bucket excavator of the present invention;

[0020] Figure 4 This is a schematic diagram of the backfill support bridge and bidirectional stripping and drainage system of the present invention;

[0021] Figure 5 This is a schematic diagram of the working line restoration of the present invention;

[0022] In the diagram: 1-Downdip coal seam; 2-Updip coal seam; 3-Horizontal coal seam; 4-Edge of downdip coal seam; 5-Edge of updip coal seam; 6-Initial working line; 7-Center axis of working line; 8-Initial advance direction; 9-Stripping material; 10-Eye cut; 11-Support bridge; 12-Working line at the bottom of the pit; 13-End wall of the pit bottom; 14-Initial end wall; 15-New advance direction; 16-Bottom spoil heap at the bottom of the pit; 17-Initial spoil heap; 18-New spoil heap step; 19-New stripping working line; 20-New coal mining working line. Detailed Implementation

[0023] The invention will now be further described with reference to the accompanying drawings.

[0024] 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.

[0025] like Figures 1 to 5As shown, this invention provides a technical solution comprising five steps: cutting and pushing the eye, digging with a bucket shovel, backfilling the support bridge, bidirectional stripping and drainage, and restoring the working line. Figure 1 As shown, based on the contact time between the initial advance direction 8 of the open-pit mine and the concave coal seam, the first inclined coal seam encountered by the open-pit mine is called the downward-dipping coal seam 1, the subsequent inclined coal seam is called the upward-dipping coal seam 2, the non-concave coal seam connected to the downward-dipping coal seam 1 and the upward-dipping coal seam 2 is called the horizontal coal seam 3, the boundary between the downward-dipping coal seam 1 and the horizontal coal seam 3 is called the downward-dipping coal seam edge 4, and the boundary between the upward-dipping coal seam 2 and the horizontal coal seam 3 is called the upward-dipping coal seam edge 5.

[0026] Cutting and pushing: such as Figure 2 As shown, before the starting working line 6 of the open-pit mine advances to the edge 4 of the downward-sloping coal seam, the stripping material 9 above the coal seam is stripped ahead of the starting advancing direction 8 of the open-pit mine, with the central axis 7 of the working line as the axis, forming a cutting groove 10 that spans the entire area of ​​the downward-sloping coal seam 1 and the upward-sloping coal seam 2. The bottom width of the cutting groove 10 is B=2H*arctanβ+A, where H is the maximum depth of the downward-sloping coal seam 1 and the upward-sloping coal seam 2 indented relative to the horizontal coal seam 3, β is the maximum slope angle of the open-pit mine end face, 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.

[0027] Drilling with a bucket excavator: such as Figure 3 As shown, taking advantage of the easy digging characteristics of the bucket shovel, the cut groove 10 is dug down and horizontally expanded. The horizontal expansion direction is perpendicular to the initial advance direction 8 of the open-pit mine. After the bucket shovel digs down to the lowest point of the coal seam, it stops digging and only horizontal expansion is carried out on both sides until the width of the expanded pit bottom reaches the minimum pit bottom width.

[0028] Backfill support bridge: such as 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. The expanded stripped material is directly discharged to the center of the pit bottom, constructing a support bridge 11 connecting the bottom plates of the downward-sloping coal seam 1 and the upward-sloping coal seam 2. The support bridge 11 has three functions: first, it constructs a connecting passage on both sides to facilitate equipment movement; second, it provides 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 down; and third, the support bridge 11 will serve as the starting point for the subsequent spoil heap.

[0029] Two-way stripping and drainage: such as Figure 4As shown, during the backfilling of the support bridge, the stripping material and coal seam within the range of the downward-sloping coal seam 1 and the upward-sloping coal seam 2 will be excavated simultaneously to form the open-pit mine bottom working line 12, which is composed of a coal mining area and a stripping area. The edge 4 of the downward-sloping coal seam and the edge 5 of the upward-sloping coal seam will each be changed to the pit bottom end wall 13, and the two sides of the open-pit mine starting end wall 14 will each be changed to an open-pit mine bottom working line 12. The new advance direction 15 of the open-pit mine will be changed to a direction perpendicular to the starting advance direction 8. At the same time, the support bridge 11 will be continuously raised and advance along the pit bottom working line 12, thereby forming the pit bottom spoil disposal area 16, and finally connecting with the starting spoil disposal area 17. When the height of the support bridge 11 reaches the bottom plate position of the horizontal coal seam 3, the spoil disposal area near the side of the upward-sloping coal seam 2 will no longer extend to the side of the upward-sloping coal seam 2, but will leave a minimum pit bottom width distance at the bottom, and gradually form a new spoil disposal step 18 according to the maximum slope angle of the open-pit mine spoil disposal area. In view of the low strength of the stripped mudstone in the south, the support bridge 11 can be constructed by mixing the stripped mud with solid waste. During the construction process, electrode tubes are installed and electrolytes are injected to carry out electrochemical modification, thereby forming a high-strength seepage-proof bridge body. On the one hand, it can strengthen the support, and on the other hand, it can effectively prevent groundwater from seeping in and affecting the initial strength of the support bridge.

[0030] As the backfilling support bridge 11 continues, the pit bottom working line 12 is continuously pushed forward in both directions along the new advance direction 15 of the open-pit mine. The stripped material within the range of the downward-dip coal seam 1 and the upward-dip coal seam 2 is continuously excavated, and the coal resources therein are continuously mined.

[0031] Workline restoration: such as Figure 5 As shown, when the bidirectional stripping and mining advances to a distance of 14 L from the starting end of the open-pit mine, the bottom end of the open-pit mine 13 above the horizontal coal seam 3 after the edge of the updip coal seam 5 begins to expand towards the side of the starting direction of the open-pit mine 8, and gradually forms the new stripping working line 19 and the new coal mining working line 20. In order to achieve a perfect continuity of open-pit mine production, it should be ensured that the new stripping working line 19 and the new coal mining working line 20 are just completed when the coal resources at a distance of L are mined out.

[0032] When the bidirectional stripping and dumping advances to the starting end 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 platform 18 of the dumping ground are formed. Thereafter, the new stripping working line 19 and the new coal mining working line 20 continue to be mined along the starting advance direction 8 of the open-pit mine, and the new dumping platform 18 of the dumping ground follows. The open-pit mine mining technology and arrangement are restored to the state before the over-dip and down-dip coal seams.

[0033] 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.

[0034] 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 of open pit mining of a dip slope, characterized in that, It includes five steps: cutting and pushing, digging with a bucket shovel, backfilling and supporting the bridge, bidirectional stripping and drainage, and restoration of the working line; Cutting and pushing: Before the starting working line (6) of the open-pit mine advances to the edge of the downward-dipping coal seam (4), the stripping material above the coal seam (9) is stripped ahead of the starting advancing direction (8) of the open-pit mine, with the central axis (7) of the working line as the axis, forming a cutting groove (10) that spans the entire area of ​​the downward-dipping coal seam (1) and the upward-dipping coal seam (2). Pulling bucket excavation: Use the pulling bucket to excavate and horizontally expand the cut groove (10). After excavating to the lowest point of the coal seam depression, stop excavating and only horizontally expand until the width of the expanded pit bottom reaches the minimum pit bottom width. Backfill support bridge: 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. The expanded stripped material is directly discharged to the center of the pit bottom to construct a support bridge (11) connecting the bottom plate of the downward inclined coal seam (1) and the upward inclined coal seam (2). Two-way stripping and backfilling: During the backfilling of the support bridge, the stripping material and coal seam within the range of the downward-sloping coal seam (1) and the upward-sloping coal seam (2) will be excavated simultaneously to form the open-pit mine bottom working line (12) composed of the coal mining area and the stripping area. At the same time, the support bridge (11) will be continuously raised and will advance along the pit bottom working line (12) to form the pit bottom spoil disposal site (16) and eventually connect with the initial spoil disposal site (17). Working line restoration: When the bidirectional stripping and drainage advance reaches the distance of L from the starting end of the open-pit mine (14), the bottom end of the open-pit mine (13) above the horizontal coal seam (3) after the edge (5) of the up-dip coal seam begins to expand towards the side of the starting direction (8) of the open-pit mine; When the bidirectional stripping and dumping advances to the starting end of the open-pit mine (14), 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 platform (18) of the dumping site are formed. After that, the new stripping working line (19) and the new coal mining working line (20) continue to be mined along the starting advance direction (8) of the open-pit mine, and the new dumping platform (18) of the dumping site follows the advance. The open-pit mining process and arrangements have been restored to their state before the over-dip coal seams.

2. A method of open cut mining of a dip slope according to claim 1 wherein, The bottom width of the cut groove (10) is B=2H*arctanβ+A; where H is the maximum depth of the downward-dip coal seam (1) and the upward-dip 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. A method of open cut mining of a dip slope according to claim 1 wherein, In the bidirectional stripping and dumping process, when the height of the support bridge (11) reaches the bottom plate of the horizontal coal seam (3), the dumping ground near the side of the upward-sloping coal seam (2) no longer extends to the side of the upward-sloping coal seam (2), but instead reserves the minimum pit bottom width distance at the bottom, and gradually forms a new dumping step (18) of the dumping ground according to the maximum slope angle of the open-pit mine dumping ground.

4. The method for open-pit mining on a dipping slope according to claim 3, characterized in that, The supporting 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 carried out to form a high-strength seepage-proof bridge body.

5. The method for open-pit mining on a dipping slope according to claim 1, characterized in that, The distance L in the working line restoration 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 distance L have just been mined.

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