Seasonal mining method for strip mine

Abstract

The invention discloses a seasonal mining method for an open-pit mine. The seasonal mining method comprises the five steps of advanced stripping, groove cutting depth, pit bottom inner drainage, transverse stripping and transverse mining, groove reserving along a panel and continuous preparation. According to the seasonal mining method, an advanced flat panel is reserved, and weathering and spontaneous combustion after large-area exposure of a coal seam can be avoided; the total length of the transverse mining working lines is not smaller than the length of the strip mine working lines before implementation, and the capacity of the strip mine cannot be reduced; the pit bottom space of the strip mine is adjusted and used in advance, so that the problem that the inner discharge space is insufficient during concentrated stripping is solved, and the problem that the transportation distance of stripped objects is increased in the advanced stripping process is also avoided; a construction space is provided for the next procedure by a groove reserved along the coil; according to the method, the relation between mining, stripping and discharging of the strip mine is re-coordinated on the whole, the mining area space is adjusted, mining area production is not thoroughly modified, construction is easy, and the management difficulty is low.

Description

Technical Field

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

[0002] ‌The winter in the northwest of China is cold, the freezing period is long, the demand for coal is large, and the open-pit mines advance quickly. However, the frozen soil is severe in winter, and the cost of stripping in open-pit mines is high, which is not convenient for stripping operations. During the non-winter period, the amount of coal required is small, and the mine advances slowly, but the temperature is high, which is convenient for rock stripping operations. High temperature also easily causes spontaneous combustion of exposed coal. In order to adapt to the climatic conditions and coal demand in different seasons, a number of seasonal open-pit mines have emerged in the northwest, that is, coal mining is carried out throughout the year, and winter is faster than other seasons, while stripping work is usually arranged in spring, summer and autumn. Stripping is stopped in winter or only a small amount of stripping is carried out. Although seasonal mining adapts to the climate and coal market environment, it also causes insufficient internal discharge space during the concentrated stripping period (i.e. spring, summer and autumn) each year. When the stripping work stops at the end of autumn, the amount of exposed coal in the open-pit mine is large and prone to spontaneous combustion. Before the stripping work starts in the second year, the pit bottom is wide, space is wasted, the internal discharge distance is long, and the internal discharge cost is high. Summary of the invention

[0003] In view of the problems existing in the above-mentioned prior art, the present invention provides a seasonal mining method for open-pit mines, which ensures the production capacity of open-pit mines, shortens the transportation distance of stripping materials, and reduces stripping costs by coordinating the relationship between mining and stripping in open-pit mines and adjusting the mining area space.

[0004] To achieve the above object, the present invention provides the following technical solution: a seasonal open-pit mining method, including five steps of advanced stripping, deep grooving, inner drainage at the bottom of the pit, horizontal stripping and mining, grooving along the plate and subsequent preparation: Advanced stripping: At the beginning of the concentrated stripping period of the open-pit mine, except for the first stripping step on the upper part of the coal seam, all other stripping steps above the coal seam are accelerated to advance stripping along the direction of the open-pit mine advancement, forming an advance flat plate on the upper part of the coal seam. The width of the advance flat plate in the advancement direction is greater than or equal to the annual advancement rate N of the open-pit mine. The advance stripping should be completed before the end of the concentrated stripping period of the year; Grooving depth: During the advance stripping process, starting from the bottom of the open pit, along the direction of the open pit advance, the eye-cutting groove is excavated on the advance flat plate, the eye-cutting groove runs through the entire advance flat plate, and the depth reaches the bottom plate of the coal seam; the width of the eye-cutting groove on the bottom plate of the coal seam shall not be less than the minimum pit bottom width; Pit bottom inner row: The stripping materials produced in the advanced stripping and trenching steps are directly dumped to the entire area of ​​the open pit bottom, forming a pit bottom dump. The height of the lowest dumping step in the pit bottom dump is the same as the height of the coal seam and is completely connected to the coal step of the coal seam. The pit bottom dump is gradually connected with the dump as a whole; Horizontal stripping and horizontal mining: When winter comes or the bottom of the open-pit mine is buried and the original working line of the open-pit mine is not suitable for mining, when the length of any cutting groove reaches the minimum working line length, the cutting groove is used as the starting point, and the horizontal stripping working line is deployed towards the open-pit mine end walls on both sides to strip the stripping on the advance flat plate; then the horizontal mining working line is deployed to mine the coal below the advance flat plate; Grooves along the plate: During the advancement of the horizontal mining work line, a horizontal mining pit bottom is formed in the mined area. When the width of the horizontal mining pit bottom exceeds 2 times the minimum pit bottom width, the stripping material produced during the horizontal stripping process of the horizontal mining pit bottom is formed into a horizontal mining dump. The horizontal mining dump is connected to the pit bottom dump, and a communication groove is reserved near the side of the advance flat plate of the horizontal mining dump; Preparation: At the end of winter, all the coal in the advance flat plate is mined, and the concentrated stripping period of the next year begins. The above steps are repeated to complete the subsequent annual mining, stripping and rowing work.

[0005] Furthermore, during the advance stripping process, the stripping and coal mining steps within the advance flat plate range are advanced normally along the open-pit mine advancement direction to mine the required amount of coal at the moment.

[0006] Furthermore, the number of the eye-cutting grooves n≥(L / N) / 2, wherein N is the annual advancement of the open-pit mine, and L is the length of the original working line of the open-pit mine.

[0007] Furthermore, when the number of the eye-cutting grooves exceeds one, the eye-cutting grooves are evenly and equidistantly distributed within the range of the leading flat plate.

[0008] Furthermore, the width of the communication groove is the minimum pit bottom width, and the length runs through the open-pit mine end walls on both sides.

[0009] Furthermore, the two steps of horizontal stripping and mining and leaving grooves along the plate are all completed before the start of the concentrated stripping period in the next year.

[0010] Compared with the prior art, the present invention retains the advanced flat plate to avoid weathering and spontaneous combustion of coal seams after large-scale exposure; the total length of multiple horizontal mining working lines is not less than the length of the open-pit mine working line before the implementation of the present invention, which can maintain the open-pit mine production capacity without reduction; the open-pit mine bottom space is adjusted and used in advance, which not only solves the problem of insufficient internal discharge space during concentrated stripping, but also avoids the problem of longer stripping material transportation distance during advanced stripping; grooves are left along the plate to provide construction space for the next step of the process; the present invention as a whole only re-coordinates the relationship between open-pit mining, stripping and discharge, adjusts the mining area space, and does not make a thorough modification to the mining area production, so the construction is simple and the management difficulty is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the advanced stripping and grooving deepening steps of the present invention; Figure 2 It is a schematic diagram of the state of the pit bottom internal drainage and horizontal stripping and horizontal mining steps of the present invention; Figure 3 for Figure 2 Schematic diagram of the middle AA section; Figure 4 It is a schematic diagram of the steps of horizontal stripping and horizontal mining and leaving grooves along the plate according to the present invention; In the figure: 1-coal seam; 2-stripping step; 3-open pit advancement direction; 4-advance flat plate; 5-open pit bottom; 6-eye cutting groove; 7-original working line of open pit; 8-bottom spoil dump; 9-spoil dump; 10-horizontal stripping working line; 11-horizontal mining working line; 12-horizontal mining end wall; 13-horizontal mining bottom; 14-horizontal mining spoil dump; 15-communication groove; 16-open pit end wall. DETAILED DESCRIPTION

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

[0013] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0014] like Figures 1 to 4 As shown, the present invention provides a technical solution, including five steps: advance stripping, deep grooving, inner row at the pit bottom, horizontal stripping and mining, leaving grooves along the plate and subsequent preparation.

[0015] like Figure 1As shown, advance stripping: at the beginning of the concentrated stripping period of the open-pit mine, that is, when the ice thaws in spring every year, except for the first stripping step 2 on the top of the coal seam 1, the other stripping steps 2 above the coal seam 1 are accelerated in the advance direction 3 of the open-pit mine, and an advance flat plate 4 is formed on the top of the coal seam 1. The width of the advance flat plate 4 in the advance direction should be greater than or equal to the annual advance rate N of the open-pit mine. The annual advance rate N of the open-pit mine is a value that has been determined when the open-pit mine is built. It generally does not change, and the value of each open-pit mine is different. Advanced stripping should be completed before the end of the concentrated stripping period of the year, that is, at the end of autumn.

[0016] During the advance stripping process, the stripping and coal mining steps within the advance flat plate 4 are normally advanced along the open-pit mine advancement direction 3 to mine the required amount of coal at the moment. The first stripping step 2 on the upper part of the coal seam 1 is not advanced stripped in order to cover the coal seam and prevent the coal seam 1 from weathering and spontaneous combustion after being exposed to a large area.

[0017] Cutting depth: During the advanced stripping process, starting from the open pit bottom 5, along the open pit advancing direction 3, a trench is excavated on the advanced flat plate 4 as the eye-cutting groove 6, which runs through the entire advanced flat plate 4 in length and reaches the bottom plate of the coal seam 1; the width of the eye-cutting groove 6 on the bottom plate of the coal seam 1 is not less than the minimum pit bottom width; the number of eye-cutting grooves 6 n is determined according to the correlation between the annual advancement rate N of the open pit and the length L of the original working line 7 of the open pit, generally n ≥ (L / N) / 2; the core logic of this relationship is to ensure that the total length of the subsequent horizontal mining working line 11 is not less than the length of the open pit working line 7 before the implementation of the plan, thereby maintaining the open pit mine production capacity. Furthermore, when the number of eye-cutting grooves 6 exceeds 1, they should be evenly and equidistantly distributed within the range of the advanced flat plate 4.

[0018] like Figure 2 and Figure 3 As shown, the discharge at the bottom of the pit: the stripping materials produced in the advance stripping and grooving steps are directly discharged to the entire area of ​​the bottom of the open-pit mine 5, forming a pit bottom dump 8. In order to facilitate the secondary stripping construction during the mining of the coal seam 1 in the horizontal stripping and horizontal mining steps, the height of the lowest discharge step of the pit bottom dump 8 is the same as the height of the coal seam 1 and is completely connected with the coal step of the coal seam 1. The pit bottom dump 8 is gradually connected with the dump 9 as a whole.

[0019] The purpose of the internal discharge step at the pit bottom is to use the pit space to discharge the stripped materials. Traditional open-pit mining must have pit bottom space for equipment operation. The present invention uses the coordination of the grooving step, the pit bottom internal discharge step and the subsequent cross-stripping and cross-mining steps to adjust and use the space of the early open-pit mine bottom 5 in advance, and then regenerate multiple small pit bottom spaces through the cross-stripping and cross-mining steps; on the one hand, it solves the problem of insufficient internal discharge space during concentrated stripping, and on the other hand, it avoids the problem of longer transport distance of stripped materials during advanced stripping.

[0020] like Figure 4 As shown, horizontal stripping and horizontal mining: when winter comes or the open-pit mine bottom 5 is buried and the original open-pit working line 7 does not meet the mining conditions, when the length of any cutting groove 6 reaches the minimum working line length, it is generally calculated comprehensively based on the mining equipment. The data of each open-pit mine are inconsistent. Then, take the cutting groove 6 as the starting point, and deploy the horizontal stripping working line 10 towards the open-pit end walls 16 on both sides to strip the stripping materials on the advance flat plate 4; then deploy the horizontal mining working line 11 to mine the coal under the advance flat plate 4; one cutting groove 6 can form two groups of stripping working lines and coal mining working lines with opposite advancing directions. During the horizontal stripping and horizontal mining process, the original open-pit stripping step 2 and the dumping step become the horizontal mining end wall 12.

[0021] Since the pit bottom internal drainage step causes the pit bottom dump 8 to be connected to the coal seam 1, during the horizontal stripping and mining process, the pit bottom dump 8 connected to the coal seam 1 needs to be stripped for the second time to ensure that the coal at the connection position is completely mined.

[0022] Leaving grooves along the plate: during the advancement of the horizontal mining work line 11, a horizontal mining pit bottom 13 is formed in the mined area. When the width of the horizontal mining pit bottom 13 exceeds 2 times the minimum pit bottom width, the stripping materials produced during the horizontal stripping process of the horizontal mining pit bottom 13 are discarded to form a horizontal mining dump 14. The horizontal mining dump 14 is connected to the pit bottom dump 8. A groove is reserved on the side of the horizontal mining dump 14 close to the advance flat plate 4 as a connecting groove 15. The width of the connecting groove 15 is the minimum pit bottom width, and the length runs through the open-pit end walls 16 on both sides. Its function is to provide construction space for the next step of the process. The two steps of horizontal stripping and mining and leaving grooves along the plate are all completed before the start of the concentrated stripping period in the next year.

[0023] Follow-up preparation: At the end of winter, the coal in the advanced flat plate 4 is mined out, and the concentrated stripping period of the next year begins. Follow the above steps and so on to complete the subsequent annual mining, stripping and rowing work.

[0024] It will be apparent to those skilled in the art that the 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 the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0025] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any slight modification, equivalent substitution and improvement made to the above embodiment based on the technical essence of the present invention should be included in the protection scope of the technical solution of the present invention.

Claims

1. A seasonal mining method for open pit mines, including five steps: advance stripping, deep cutting, inner drainage at the bottom of the pit, horizontal stripping and horizontal mining, groove retention along the plate and subsequent preparation: Advanced stripping: At the beginning of the concentrated stripping period of the open-pit mine, except for the first stripping step (2) on the upper part of the coal seam (1), all other stripping steps (2) above the coal seam (1) are accelerated to advance stripping along the open-pit mine advancement direction (3), forming an advance flat plate (4) on the upper part of the coal seam (1), and the width of the advance flat plate (4) in the advancement direction is greater than or equal to the annual advancement rate N of the open-pit mine. The advance stripping should be completed before the end of the concentrated stripping period of the year; Grooving depth: During the advance stripping process, starting from the open pit bottom (5), along the open pit advancing direction (3), a cutting groove (6) is excavated on the advance plate (4), the cutting groove (6) passing through the entire advance plate (4) and reaching a depth down to the bottom plate of the coal seam (1); the width of the cutting groove (6) on the bottom plate of the coal seam (1) is not less than the minimum pit bottom width; Pit bottom inner row: The stripping material generated in the advanced stripping and trenching steps is directly discharged to the entire area of ​​the open pit bottom (5) nearby to form a pit bottom dump (8). The height of the lowest dumping step of the pit bottom dump (8) is the same as the height of the coal seam (1) and is completely connected to the coal step of the coal seam (1). The pit bottom dump (8) is gradually connected to the dump (9) as a whole; Horizontal stripping and horizontal mining: When winter comes or the open-pit mine bottom (5) is buried and the original open-pit mine working line (7) is not ready for mining, when the length of any cutting groove (6) reaches the minimum working line length, the cutting groove (6) is used as the starting point, and the horizontal stripping working line (10) is deployed towards the open-pit mine end walls (16) on both sides to strip the stripping material on the advance flat plate (4); and then the horizontal mining working line (11) is deployed to mine the coal below the advance flat plate (4); Grooves along the plate: During the advancement of the horizontal mining working line (11), a horizontal mining pit bottom (13) is formed in the mined area. When the width of the horizontal mining pit bottom (13) exceeds 2 times the minimum pit bottom width, the stripping material generated during the horizontal stripping process of the horizontal mining pit bottom (13) is discarded to form a horizontal mining dump (14). The horizontal mining dump (14) is connected to the pit bottom dump (8). A communication groove (15) is reserved on the side of the horizontal mining dump (14) close to the advance flat plate (4). Preparation: At the end of winter, the coal in the advanced flat plate (4) is mined out, and the concentrated stripping period of the next year begins. The above steps are repeated to complete the subsequent annual mining and stripping work.

2. A seasonal open-pit mining method according to claim 1, characterized in that: During the advanced stripping process, the stripping and coal mining steps within the advanced flat plate (4) are normally advanced along the open-pit mine advancement direction (3) to mine the required amount of coal at the moment.

3. The seasonal open-pit mining method according to claim 1, characterized in that: The number of the eye-cutting grooves (6) is n≥(L / N) / 2, wherein N is the annual advancement rate of the open-pit mine, and L is the length of the original working line (7) of the open-pit mine.

4. A seasonal open-pit mining method according to claim 3, characterized in that: When the number of the eye-cutting grooves (6) exceeds one, the eye-cutting grooves (6) are evenly and equidistantly distributed within the range of the leading flat plate (4).

5. The seasonal open-pit mining method according to claim 1, characterized in that: The width of the communication groove (15) is the minimum pit bottom width, and the length runs through the open-pit mine end walls (16) on both sides.

6. The seasonal open-pit mining method according to claim 1, characterized in that: The two steps of horizontal stripping and mining and leaving grooves along the plate are all completed before the start of the concentrated stripping period in the next year.

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