Invasive mining method for deep open-pit mine

Abstract

The invention discloses an intrusive mining method for a deep open-pit mine. The intrusive mining method comprises three main steps of super-stripping and super-drainage, horizontal pushing and inner drainage, and top mining and reverse drainage. In the overstripping process, the original inclined goaf bottom plate is changed to be horizontal, so that an internal dumping condition is created for mining of the whole concave area, and the external displacement and the cost are reduced; in the over-drainage process, redundant stripped materials are temporarily stored in a mining area, internal drainage can be achieved through reverse drainage subsequently, and land resource occupation caused by external drainage is avoided; the horizontal pushing inner row realizes the horizontal pushing of the concave area, and the management mode is recovered before passing through the concave area, so that the management difficulty is reduced, the lifting mining or downward mining of the equipment is avoided, and the use efficiency of the equipment is improved; in the upward mining and reverse discharging process, the secondary stripping super-discharging dumping site is backfilled to the downward concave area, so that the stripping ratio and the dumping space are balanced, the capacity of mining equipment is fully utilized, and the safety problem caused by the idle goaf is avoided; and various problems confronted by the current concave area are avoided by adjusting the correlativity of the stripping row in time and space.

Description

Technical Field

[0001] The invention relates to an open-pit mining method, in particular to an intrusive mining method for a deep-pit open-pit mine. Background Art

[0002] Due to crustal movement, coal seams that may have previously been nearly horizontal are now locally or even widely concave in the middle, with opposite, upward-dipping sides, similar to a "√" distribution structure. When open-pit mining is used to mine the coal resources in this area, the deep-pit open-pit mine described in this invention is formed. When open-pit mining in this area, the following problems will arise: First, there is an imbalance in the space for soil removal. Conventional open-pit mining uses the coal seam floor as the boundary. If this traditional solution is used in concave open-pit mines, when the angle of the coal seam floor exceeds 20 degrees, the floor will no longer be able to drain the soil internally. This will result in the open-pit mining being unable to achieve internal drainage before the lowest point of the concave, and the stripping material will be discharged externally, occupying the land. After passing the lowest point of the concave, the space in the concave goaf is rapidly released, and the stripping material is insufficient to fill it, causing regional safety issues. Second, there is an imbalance in the stripping ratio. After mining passes the lowest point of the concave, the coal seam gradually tilts upward, and the stripping volume decreases rapidly. Compared to before the lowest point of the concave, the stripping ratio is significantly lower, posing a challenge to mine management. The third is the imbalance in equipment utilization efficiency. With the imbalance of stripping ratio, in order to ensure the output of open-pit mines, a large number of various excavation and transportation equipment are needed in the early stage, but this causes serious redundancy of equipment capacity in the later stage. Summary of the Invention

[0003] In response to the problems existing in the above-mentioned prior art, the present invention provides an intrusive mining method for deep open-pit mines, which avoids the problems of imbalance in soil discharge space, imbalance in stripping ratio and imbalance in equipment utilization efficiency by adjusting the temporal and spatial correlation between mining, stripping and soil discharge.

[0004] To achieve the above object, the present invention provides the following technical solution: a deep open pit mine intrusive mining method, comprising the following steps: Overstripping: When the open-pit mine working line advances to the starting point of the concave, the original working side of the open-pit mine gradually increases the slope angle to the maximum slope angle through the steep side and maintains the advancement at this angle; starting from the concave starting point, the open-pit mine working bench begins to extend vertically downward, forming a concave end side on the side of the original inner dump, and forming a concave working side in the concave area, which is connected to the original working side; The concave end wall intrudes into the rock layer below the coal seam floor. On the basis of maintaining the minimum pit bottom width distance between the lowest step of the concave end wall and the lowest step of the concave working wall, the two walls continue to extend downward until they reach the horizontal position of the lowest point of the concave coal seam, and then stop sinking, at this time forming a horizontal open-pit mine bottom; Super-drainage: The stripping material produced during the super-stripping process is discharged along the direction of the open-pit mine with the super-drainage point as the starting point to form a super-drainage dump; Push: The concave working side and the original working side are continuously advanced horizontally in the direction of open-pit mine advancement, mining the concave coal seam, stripping the stripping materials in the concave area, and continuously widening the width of the open-pit mine bottom along the advancement direction; Internal dumping: As the open pit bottom continues to widen, a concave inner dumping yard is constructed layer by layer from the bottom of the open pit along one side of the concave end wall. The stripping materials generated during the horizontal pushing process are directly discharged into the concave inner dumping yard, thus realizing the internal discharge of stripping materials. Upper mining: After the horizontal push and inner row are completed, the open pit mine continues to advance, and the lowest step of the working wall begins to be close to the coal seam floor and gradually moves upward; Backflow: During the mining process, a large amount of space in the concave goaf of the open-pit mine is released. At this time, the secondary stripping and over-discharge dumping site are used, and the secondary stripped materials are transported back to fill the concave goaf.

[0005] Furthermore, the super-drainage point is the lowest point of the concave coal seam as the starting point, and the contact point between the working side and the ground surface is calculated along the advancing direction according to the maximum working side slope angle.

[0006] Furthermore, the sunken inner dumping ground gradually rises and is eventually connected with the original dumping ground to form an integrated dumping ground.

[0007] Furthermore, the horizontal pushing and inner rowing is continuously implemented until the lowest step of the concave working side reaches the lowest point of the concave coal seam. At this time, the original working side is just advanced to the super rowing point, and the horizontal pushing and inner rowing stops.

[0008] Furthermore, when the upper mining starts, the original working gang just advances to the position of the super-discharge point.

[0009] Compared with the prior art, the present invention changes the originally inclined bottom plate of the goaf into a horizontal state during the over-stripping process, creates internal soil discharge conditions for the mining of the entire concave area, reduces external discharge volume, and reduces soil discharge costs; during the over-discharge process, the excess stripping materials are temporarily stored in the mining area, and subsequently internal discharge can be achieved through reverse discharge, avoiding the occupation of land resources caused by external discharge; the horizontal push internal discharge realizes the horizontal advancement of the concave area, and the management mode is restored to the state before passing the concave area, which reduces the management difficulty, avoids the lifting or downward mining of equipment, and improves the equipment utilization efficiency; in the upper mining reverse discharge process, the secondary stripping and over-discharge dump is backfilled into the concave area, which balances the stripping ratio and soil discharge space, fully utilizes the capacity of mining equipment, and avoids safety problems caused by idle goaf; the present invention effectively avoids various problems faced by the concave area recorded in the background technology by adjusting the correlation between mining, stripping, and soil discharge in time and space. The implementation process of the present invention is easy to understand and operate, and will not increase the difficulty of mine production management. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a cross-sectional view of an open-pit mine in the super-stripping and super-drainage stages of the present invention; Figure 2 This is a cross-sectional view of an open-pit mine during the horizontal push and inner row stage of the present invention; Figure 3 This is a cross-sectional view of an open-pit mine in the reverse mining stage of the present invention; In the figure: 1-open pit mine advancement direction; 2-concave coal seam; 3-concave starting point; 4-concave end point; 5-original dumping ground; 6-original working wall; 7-concave end wall; 8-concave working wall; 9-rock layer below the coal seam floor; 10-lowest point of the concave coal seam; 11-open pit bottom; 12-over-drainage point; 13-over-drainage dumping ground; 14-concave inner dumping ground. DETAILED DESCRIPTION

[0011] The present invention will be further described below with reference to the accompanying drawings.

[0012] 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. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0013] like Figures 1 to 3 As shown, the present invention provides a technical solution, including three steps: overstripping and overdischarge, horizontal pushing and internal discharge, and upper mining and reverse discharge. First, several concepts are defined to facilitate the subsequent description of the solution. According to the open-pit mine advancement direction 1, the first contact point between the open-pit mine working line and the concave coal seam 2 is called the concave starting point 3, and the last contact point is called the concave end point 4. The dumping site before the open-pit mine working line advances to the concave starting point is called the original dumping site 5, and the working area above the line connecting the concave starting point 3 and the concave end point 4 is called the original working area 6.

[0014] Overstripping: When the open-pit mine working line advances to the concave starting point 3, the original working side 6 of the open-pit mine gradually increases the side slope angle to the maximum side slope angle through the steep side adding and merging method, and keeps advancing at this angle. The specific angle varies according to the geology of the open-pit mine and the coal seam covering conditions, and is usually between 25° and 40°; starting from the concave starting point 3, the open-pit mine working step begins to extend vertically downward, forming a concave end side 7 on the side of the original inner spoil dump, and forming a concave working side 8 in the concave area, which is connected to the original working side 6.

[0015] The extension boundary of the concave end wall 7 is no longer bounded by the traditional coal seam floor, but extends downward at the maximum end wall slope angle. The specific angle is determined according to the geological conditions, generally not less than 25° and greater than the concave inclination angle of the coal seam; thus, the concave end wall 7 invades the rock layer 9 below the coal seam floor, and compared with traditional mining methods, the stripping material is excessively stripped.

[0016] On the basis of maintaining the minimum pit bottom width distance between the lowest step of the concave end wall 7 and the lowest step of the concave working wall 8, the two walls continue to extend downward until they reach the horizontal position of the lowest point 10 of the concave coal seam, and then stop sinking, at this time forming a horizontal open-pit mine bottom 11.

[0017] At this point, the overstripping is completed. During the downward extension of the two sides, the coal resources are mined simultaneously, and some stripping materials below the coal seam floor are overstripped.

[0018] Super-discharge: starting from the lowest point 10 of the lower concave coal seam, along the advancing direction 1, the contact point between the working side and the ground surface is calculated according to the maximum working side slope angle as the super-discharge point 12; the super-stripping process cannot achieve internal discharge, and the stripping material produced by the super-stripping process is discharged along the open-pit mine direction with the super-discharge point 12 as the starting point, forming a super-discharge dump 13; because the super-discharge dump 13 is ahead of the original working side 6, it invades the future mining area of the open-pit mine in advance, which is super-discharge.

[0019] Horizontal push: The concave working side 8 and the original working side 6 continue to advance horizontally in the open-pit mine advancement direction 1, mining the concave coal seam 2, stripping the stripping materials in the concave area, and continuously widening the width of the open-pit mine bottom 11 along the advancement direction 1.

[0020] Internal discharge: As the open pit bottom 11 continues to widen, a concave internal dumping ground 14 is constructed layer by layer along one side of the concave end wall 7 starting from the open pit bottom 11. The stripping materials produced during the horizontal pushing process are directly discharged into the concave internal dumping ground 14 to achieve internal discharge of the stripping materials.

[0021] As the concave inner dump 14 gradually rises, it eventually connects with the original dump 5 to form an integrated dump. The horizontal push inner dump continues until the lowest step of the concave working platform 8 reaches the lowest point 10 of the concave coal seam. At this time, the original working platform 6 just advances to the super-drainage point 12, and the horizontal push inner dump stops.

[0022] Upper mining: After the horizontal push and inner row are completed, the open-pit mine continues to advance. At this time, since the concave coal seam 2 begins to gradually tilt upward, the lowest step of the working platform begins to be close to the bottom of the coal seam and gradually moves upward, that is, the lowest step gradually moves upward to form upper mining.

[0023] Reverse discharge: During the upper mining process, a large amount of space in the concave goaf of the open-pit mine is released, and the upper mining process can produce a large amount of coal with less stripping. If the stripping material formed by stripping the original stratum above the coal seam is relied on alone, the concave goaf cannot be filled. At this time, the stripping material super-discharged in the super-stripping and super-discharge steps begins to play a role. At the beginning of the upper mining, the original working gang 6 just advances to the position of the super-discharge point 12. The upper mining continues, and the original working gang 6 advances. At this time, the secondary stripping and super-discharge dump 13 begins. The secondary stripping material is reversely transported and backfilled to the concave goaf, making full use of the huge goaf space formed by the concave process and realizing the reverse discharge of the super-discharge dump 13.

[0024] As the upward mining continues to advance, the goaf in the concave area is completely filled. At this time, the open-pit mine returns to the normal mining and internal drainage process before passing the concave area.

[0025] 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.

[0026] 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 deep open pit mine intrusive mining method, characterized in that: The following steps are involved: Overstripping: When the open-pit mine working line advances to the concave starting point (3), the original working side (6) of the open-pit mine gradually increases the side slope angle to the maximum side slope angle by steepening and merging sections, and keeps advancing at this angle; starting from the concave starting point (3), the open-pit mine working step begins to extend vertically downward, forming a concave end side (7) on the side of the original inner spoil dump, and forming a concave working side (8) in the concave area, and connected to the original working side (6); The concave end wall (7) intrudes into the rock layer (9) below the coal seam floor, and the minimum pit bottom width distance is maintained between the lowest step of the concave end wall (7) and the lowest step of the concave working wall (8). The two walls continue to extend downward until they reach the horizontal position of the lowest point (10) of the concave coal seam, and then stop concave, forming a horizontal open pit pit bottom (11); Super-discharge: The stripping material produced during the super-discharge process is discharged along the open pit mine direction starting from the super-discharge point (12), forming a super-discharge dump (13); Pushing: The concave working side (8) and the original working side (6) are continuously pushed forward horizontally in the open pit advancing direction (1), mining the concave coal seam (2), stripping the stripping materials in the concave area, and continuously widening the width of the open pit bottom (11) along the advancing direction (1); Internal discharge: As the open pit bottom (11) continues to widen, a concave internal dumping ground (14) is constructed layer by layer starting from the open pit bottom (11) along one side of the concave end wall (7). The stripping materials generated during the horizontal pushing process are directly discharged into the concave internal dumping ground (14), thus realizing internal discharge of the stripping materials. Upper mining: After the horizontal push and inner row are completed, the open pit mine continues to advance, and the lowest step of the working wall begins to be close to the coal seam floor and gradually moves upward; Backfill: During the mining process, a large amount of space in the concave goaf of the open-pit mine is released. At this time, the secondary stripping and over-discharge dump (13) are used, and the secondary stripped materials are transported back to fill the concave goaf.

2. The deep open pit mine invasive mining method according to claim 1, characterized in that: The super discharge point (12) is calculated based on the lowest point (10) of the concave coal seam and the contact point between the working side and the ground surface along the advancing direction (1) according to the maximum working side slope angle.

3. The deep open pit mine invasive mining method according to claim 1, characterized in that: The concave inner dumping ground (14) gradually rises and eventually connects with the original dumping ground (5) to form an integrated dumping ground.

4. The deep open pit mine invasive mining method according to claim 1, characterized in that: The horizontal pushing and inner rowing is continuously implemented until the lowest step of the concave working side (8) reaches the lowest point (10) of the concave coal seam. At this time, the original working side (6) just advances to the super rowing point (12), and the horizontal pushing and inner rowing stops.

5. The deep open pit mine invasive mining method according to claim 1, characterized in that: When the upper mining starts, the original working gang (6) just advances to the position of the super-discharge point (12).

Images