Two-section parallel medium-length hole low dilution mining method for steeply inclined irregular thin ore vein

Abstract

The present application relates to metal ore body mining technical field, especially to a kind of steeply inclined irregular thin vein two subsection parallel medium-length hole low dilution mining method, steps are: according to the occurrence and inclination of ore body, stage is divided, two subsections are arranged in stope; excavate stage transport along vein roadway, excavate multiple ore drawing through vein roadway to ore body disappears, end personnel ventilation shaft for exploration and ventilation is arranged;Excavate chute connecting lane and chute;Excavate bottom intravein drilling roadway, excavate top intravein drilling roadway, excavate central shaft extending along the tendency of ore body;Determine the length of ore body, the thickness of ore body, the height and tendency of ore body, construct three-dimensional space model of ore body, and meet the blasting action range limited in ore body, determine medium-length hole blasting parameters;Drill parallel medium-length hole;Back to mining.The present application has high ore body boundary control precision, low ore dilution rate, less cutting engineering quantity, safe and reliable cutting condition, and high back to mining efficiency.

Description

Technical Field

[0001] This invention relates to the field of metal ore body mining technology, specifically to a method for two-section parallel medium-deep hole mining of low-lean ore veins with steep inclination and irregular thin veins. Background Technology

[0002] Steeply dipping thin veins, a typical form of precious metal deposits, generally refer to vein-like deposits with a dip angle greater than 55° and an average thickness of less than 0.8 meters. These deposits are characterized by complex morphology, unstable spatial distribution, large variations in vein width, and numerous interbedded layers. Currently, the mainstream mining methods for these deposits both domestically and internationally are still primarily traditional processes, including: wall-cutting and backfilling, shallow-hole ore retention, and upward horizontal layered cemented backfilling mining. However, these methods generally suffer from low mechanization, high labor intensity, high production costs, poor safety, and low recovery efficiency. With advancements in mining equipment and technology, medium-deep hole mining has gradually gained attention due to its high efficiency and large production capacity. This technology utilizes down-the-hole drilling or jumbos to construct deeper blast holes (typically >5 meters deep), allowing for the caving of large quantities of ore in a single blast, offering significant advantages in operational safety, high production efficiency, and large production capacity.

[0003] However, in steeply dipping thin vein applications, as drilling depth increases, borehole deviation and decreased accuracy become prominent issues, easily leading to significant mixing with surrounding rock and a substantial increase in ore dilution. This severely restricts its widespread application in thin veins.

[0004] Therefore, it is necessary to propose a new medium-deep hole mining technology that is safe, efficient, and low-digestion suitable for steeply dipping thin veins. Summary of the Invention

[0005] This invention proposes a two-section parallel medium-deep hole mining method for steeply inclined irregular thin veins. The purpose is to address the problems of difficult drilling accuracy control, serious mixing of surrounding rock, and high safety risks in the medium-deep hole mining of steeply inclined irregular thin veins. This method can accurately control the ore body boundary, reduce the ore dilution rate, improve mining efficiency, and take into account operational safety.

[0006] This invention proposes a two-section parallel medium-deep hole low-digestion mining method for steeply inclined irregular thin veins, comprising the following steps: Based on the occurrence and dip angle of the ore body, S1 is divided into stages along the vertical strike b. Within each stage, a stope is divided along the strike a of the ore body. Within the stope, two sub-sections are arranged along the vertical strike b. S2 is excavated along the strike a of the ore body in the footwall direction d. Multiple ore-exiting cross-vein roadways are excavated in the direction of the ore body within the stage transport cross-vein roadways. The ore-exiting cross-vein roadways are excavated until the ore body disappears. End ventilation shafts that serve as both exploration and ventilation are arranged at both ends of the stope. In the stage transport cross-vein roadways, connecting roadways and ore passes are excavated along the direction away from the ore body. S3 excavates a bottom vein drilling tunnel along the ore body strike a at the bottom of the stope, excavates a top vein drilling tunnel along the ore body strike at the top of the stope, and excavates a central riser extending along the ore body dip in the middle of the ore body. S4 determines the length of the ore body along the strike a of the ore body based on the bottom and top vein drilling tunnels, obtains the thickness of the ore body through the ore-exiting vein tunnel, and determines the height and dip of the ore body based on the end ventilation shaft and the central shaft, and comprehensively constructs a three-dimensional spatial model of the ore body; based on the three-dimensional spatial model of the ore body and ensuring that the blasting action range is limited to inside the ore body, the parameters for medium-deep hole blasting are determined. S5 drills parallel medium-deep holes downward in the rock drilling tunnel within the top vein, and drills parallel medium-deep holes upward in the rock drilling tunnel within the bottom vein. S6 uses the central well of the mining area as the free face and adopts the method of retreating to both sides for mining. First, the blast holes on both sides of the central well are blasted to form a slotting space. The S7 caving ore is shoveled out through the ore extraction channel and transported along the channel to the ore bin via the ore pass. It is then hoisted to the surface by a skip.

[0007] Furthermore, the stage height in S1 is 35m to 40m, the segment height is 17.5m to 20m, and the length of the mining area is no more than 50m.

[0008] Furthermore, a support column is left between the S2 mining area and the pedestrian ventilation well at one end.

[0009] Furthermore, in S3, the central atrium also serves as a cutting atrium, and in S6, the central atrium also serves as a free surface.

[0010] Furthermore, the mining area is divided into four working areas, with the central well and the sections as the boundaries: the right upper mining area, the right lower mining area, the left upper mining area, and the left lower mining area.

[0011] Furthermore, parallel medium-deep holes are drilled downwards in the drilling tunnels within the top veins of the right upper mining area and the left upper mining area, and parallel medium-deep holes are drilled upwards in the drilling tunnels within the bottom veins of the right lower mining area and the left lower mining area.

[0012] Furthermore, in the S6 mining process, a retreat mining method is adopted towards the pedestrian ventilation shafts at both ends. The upper and lower sections are simultaneously blasted with micro-differential detonation. By controlling the sequence of micro-differential detonation, the lower section of the ore body collapses first, followed by the upper section, thus completing the sequential collapse of the two sections of the ore body in the same blasting process.

[0013] Furthermore, it also includes the following steps: S8 Ground pressure management and control: After all the ore has been extracted, the ore extraction tunnel is sealed and the goaf is cemented and backfilled to achieve ground pressure control in the goaf.

[0014] Furthermore, before the cemented backfilling, the process also includes: performing a three-dimensional scan of the goaf, calculating the volume of the goaf based on point cloud data to determine the amount of backfilling material; and constructing a sealed concrete retaining wall at the ore outlet cross-vein roadway and the bottom connecting roadway, leaving drainage holes.

[0015] Compared with existing mining technologies, the steeply inclined irregular thin vein mining method provided by this invention has the following advantages: 1. High precision in orebody boundary control. This invention utilizes bottom and top vein drilling tunnels, as well as end ventilation shafts and central shafts, to achieve multi-dimensional control of the orebody's strike, dip, and thickness. This allows for accurate determination of the orebody's length, thickness, width, and dip, resulting in a highly precise determination of its true spatial morphology (three-dimensional spatial model). In applications involving steeply dipping thin veins, this avoids the problems of borehole deviation and decreased precision with increasing drilling depth, which can lead to significant mixing with surrounding rock and a substantial increase in ore dilution.

[0016] 2. Significantly reduces ore dilution rate. Based on the three-dimensional model of the ore body and by limiting the blasting range as much as possible within the ore body, the blasting parameters for medium-deep holes (such as hole length, dip angle, and azimuth angle) can be accurately determined. Simultaneously, the hole spacing and row spacing can be dynamically adjusted according to changes in ore body thickness. Through differentiated drilling parameter control, the diffusion of blasting energy into the surrounding rock is reduced, thereby effectively lowering the surrounding rock infiltration rate.

[0017] 3. Safe and reliable cutting conditions. The central well of the mining area is used as the cutting well, eliminating the need for an additional dedicated cutting well, thus reducing construction difficulty and safety risks.

[0018] 4. High mining efficiency and high degree of mechanization. The two-section parallel medium-deep hole synchronous mining method significantly increases production capacity and significantly reduces labor intensity.

[0019] 5. High adaptability and high promotion value. It is suitable for irregular thin veins with steep inclination, large thickness variation and complex boundaries. It has strong engineering adaptability, requires less mining and cutting work, and has good prospects for promotion and application. Attached Figure Description

[0020] Figure 1 A schematic diagram of a three-dimensional structure of a steeply inclined, irregular, thin vein with two segments of parallel medium-deep borehole ore body provided in an embodiment of the present invention; Figure 2 for Figure 1 Longitudinal cross-section of a medium-deep borehole ore body awaiting mining; Figure 3 for Figure 2 Schematic diagram of the cross section at point III-III; Figure 4 for Figure 2 Schematic diagram of the cross section at point IV-IV; Figure 5 for Figure 2 Schematic diagram of the cross section at point II; Figure 6 for Figure 2 Schematic diagram of the cross section at point II-II; In the picture: 1-Stage transport roadway along the vein; 2-Ore extraction roadway through the vein; 3-End pedestrian ventilation shaft; 4-Central shaft; 5-Bottom vein drilling roadway; 6-Top vein drilling roadway; 7-Right-side upper stope; 8-Right-side lower stope; 9-Left-side upper stope; 10-Left-side lower stope; 11-Upward medium-deep hole; 12-Downward medium-deep hole; 13-Pass shaft; 14-Pass shaft connecting roadway; 15-Pillar. Detailed Implementation

[0021] To further illustrate the technical means and effects of this invention, the following description, in conjunction with embodiments and accompanying drawings, provides a further explanation of the invention. It is understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it.

[0022] This invention proposes a two-section parallel medium-deep hole low-digestion mining method for steeply dipping irregular thin veins, such as... Figures 1 to 6 As shown, it includes the following steps: S1 Stope Division: Based on the ore body's occurrence and dip angle, the stope is divided into stages perpendicular to strike b, and within each stage, stopes are further divided along strike a. Within each stope, two sub-sections are arranged perpendicular to strike b, with the sub-section height determined by the ore body's occurrence. The stage height is 35m–40m, and the sub-section height is 17.5m–20m. The stope length is no more than 50m. A pillar 15 is provided between the stope and the ventilation shaft 3 at one end, but not between the stope and the ventilation shaft 3 at the other end, to reduce pillar loss and improve resource recovery.

[0023] S2 mining preparation project implementation: Stage transport roadway 1 is excavated along the strike a of the ore body in the footwall direction (d). The strike of stage transport roadway 1 is approximately parallel to the strike of the ore body. Multiple ore-exit cross-cutting roadways 2 are excavated within stage transport roadway 1 towards the ore body. The ore-exit cross-cutting roadways 2 are excavated until the ore body disappears. Pedestrian ventilation shafts 3, serving both exploration and ventilation purposes, are arranged at both ends of the stope. The pedestrian ventilation shafts 3 at the end of the stope are excavated along the dip direction of the ore body to achieve ventilation, pedestrian access, and ore body occurrence control in the stope. Connecting ore pass 14 and ore pass 13 are excavated along stage transport roadway 1 in a direction away from the ore body. S3 Drilling Engineering Layout: In the footwall direction d, the bottom vein drilling roadway 5 is excavated along the strike of the ore body at the bottom of the stope. In the hanging wall direction c, the top vein drilling roadway 6 is excavated along the strike of the ore body at the top of the stope. A central riser 4 extending along the dip of the ore body is excavated in the middle of the stope. The central riser 4 also serves as a cutting riser. S4 Orebody Model Construction and Blasting Parameter Design: The length of the orebody along the strike a is determined based on the bottom vein drilling tunnel 5 and the top vein drilling tunnel 6. The orebody thickness is obtained through the ore extraction tunnel 2. The height and dip of the orebody are determined through the end ventilation shaft 3 and the central shaft 4. A three-dimensional spatial model of the orebody is constructed using three-dimensional software. Based on the spatial morphology, thickness variation, dip angle, and surrounding rock contact relationship of the orebody, and to ensure that the blasting action range is limited to the interior of the orebody, the blasting parameters for medium-deep holes, such as the hole length, dip angle, and azimuth angle, are determined to match the borehole axis with the orebody occurrence morphology. At the same time, the hole spacing, row spacing, and minimum resistance line are dynamically adjusted in conjunction with the orebody thickness variation. A non-equal length, non-parallel medium-deep hole arrangement is adopted to replace the traditional equal length parallel hole arrangement.

[0024] By using the bottom vein drilling tunnel 5, the top vein drilling tunnel 6, the end pedestrian ventilation shaft 3, and the central shaft 4 to achieve multi-dimensional control of the ore body's strike, dip, and thickness, precise fracturing of the thin vein profile is achieved. This ensures operational safety, significantly improves mining efficiency, and significantly reduces ore dilution rate, thus providing a safe, efficient, low-dilution, and scalable modern solution for the mining of steeply dipping thin veins.

[0025] The lengths of the upward and downward medium-deep holes are determined rationally based on the ore body morphology. The lengths of the downward-drilled medium-deep holes in the drilling roadway 6 within the top vein of the stope are determined according to the dip extension length of the ore body, while the lengths of the upward-drilled medium-deep holes in the drilling roadway 5 within the bottom vein are determined according to the ore body morphology. This further divides the stope into four working areas: upper left, lower left, upper right, and lower right. The stope is further divided into four working areas using the central raise 4 and the sub-section as boundaries: upper right stope 7, lower right stope 8, upper left stope 9, and lower left stope 10.

[0026] S5 medium-deep hole drilling construction: Drill parallel medium-deep holes downward in the rock drilling tunnel 6 in the top vein, and drill parallel medium-deep holes upward in the rock drilling tunnel 5 in the bottom vein. Small medium-deep hole trolleys are used for rock drilling operations. These machines are easy to disassemble and move, and can effectively control borehole deviation. Pneumatic charging machines are used for charging operations.

[0027] like Figure 1 and Figure 2 As shown, the medium-deep holes include upward medium-deep holes 11 and downward medium-deep holes 12. In the top vein drilling roadway 6 of the right upper mining area 7 and the left upper mining area 9, a medium-deep hole drilling rig is used to drill parallel downward medium-deep holes 12. In the bottom vein drilling roadway 5 of the right lower mining area 8 and the left lower mining area 10, a medium-deep hole drilling rig is used to drill parallel upward medium-deep holes 11.

[0028] S6 mining area: The central well 4 of the mining area is used as a free face to provide compensation space for blasting. Mining is carried out by retreating to both sides. The blast holes near the central well 4 are blasted first to form a slotting space. The mining adopts a retreat mining method towards the pedestrian ventilation wells on both sides. The upper and lower sections are blasted simultaneously in a single blast with micro-differential blasting. By controlling the micro-differential blasting sequence, the lower section of the ore body collapses first, followed by the upper section of the ore body, thus achieving the ore body of the upper and lower sections in one blasting process.

[0029] S7 Mining: The collapsed ore is shoveled out through the ore-exiting vein roadway 2, enters the stage transport along the vein roadway 1, is concentrated in the ore bin through the ore pass 13, and is then lifted to the surface by the skip.

[0030] S8 Ground pressure management and control: After all the ore has been extracted, the ore extraction tunnel 2 is sealed off, and the goaf is cemented and backfilled to achieve ground pressure control in the goaf.

[0031] After the mining is completed, a three-dimensional scan of the goaf is performed, and the volume of the goaf is calculated based on the point cloud data to determine the amount of filling material to be used. Before filling, a sealed concrete retaining wall is built at the ore-exit crossroads 2 and the bottom connecting roadway, and drainage holes are left.

[0032] The development method proposed in this invention eliminates the need for top and bottom pillars. By using high-strength cemented filling material to promptly fill the goaf, the filling material bears the load of the surrounding rock and overlying strata, thereby achieving effective management and control of the mining area pressure, improving the overall stress state of the mining area, increasing the ore recovery rate, and enhancing the long-term stability of the mining area.

[0033] Example 1 Taking a quartz vein-type gold deposit in Liaoning Province as an example, the gold ore body in this deposit mainly exists in the form of quartz veins. The surrounding rocks are mainly andesite, rhyolite, and brecciated lava. Affected by silicification and pyrite alteration, the integrity of the rock mass is poor, and it is prone to rockfall during mining, resulting in complex engineering geological conditions. At present, the mine mainly uses the cut-and-fill method and the shallow-hole retention method for mining. The ore dilution rate is generally higher than 40%, and even exceeds 50% in some local stops, resulting in low production efficiency and high safety risks.

[0034] The method for high-efficiency mining of steeply inclined, irregular, thin veins using two-section parallel medium-deep boreholes with low dilution provided by this invention, such as... Figures 1 to 6 As shown, the specific implementation steps are as follows: S1 Stope Division: Stopes are divided along the strike of the ore body. Each stope is 50m long, 40m high, and approximately 2.5m wide, with a dip angle of approximately 65°. Two sections are arranged within each stope, with the section height determined according to the ore body's occurrence. A 4m pillar is left between the stops, but no top or bottom pillars are provided.

[0035] S2 mining preparation project implementation: In the footwall direction (d) along the strike of the ore body, a transport roadway 1 along the vein is excavated, and a bottom ore-exiting cross-vein roadway 2 is excavated every approximately 12m within the transport roadway. Simultaneously, end ventilation shafts 3 are excavated at both ends of the stope, connecting to the bottom vein drilling roadway 5 or the top vein drilling roadway 6 in the adjacent stage; a central shaft 4, with a cross-sectional dimension of 2.5m × 2m, is excavated from bottom to top in the center of the stope, extending along the dip of the ore body.

[0036] S3 Drilling Engineering Layout: Drilling tunnel 5 is excavated at the bottom of the mining area along the ore body strike, drilling tunnel 6 is excavated at the top of the mining area along the ore body strike, and a central riser 4 extending along the ore body dip is excavated in the middle of the mining area. The central riser 4 also serves as a cutting riser.

[0037] S4 Ore Body Model Construction and Blasting Parameter Design: Based on the bottom vein drilling tunnel 5 and the top vein drilling tunnel 6, the length of the ore body along the strike a is determined. The thickness of the ore body is determined by the ore-exiting vein tunnel 2. The dip of the ore body is determined by the end ventilation shaft 3 and the central shaft 4. The vein length is found to be 150m to 500m, with a local extension exceeding 1000m; the ore body thickness is 0.2m to 3m, the dip angle is 65° to 80°, and the depth reaches 100m to 720m. A three-dimensional spatial model of the ore body is constructed. Based on the three-dimensional geometric model and to ensure that the blasting action range is limited to the inside of the ore body, the medium-deep hole blasting parameters are determined.

[0038] A spatial model of the ore body was established using 3D geological modeling software. Based on the ore body's geometry and spatial occurrence, the stope was divided into left and right working areas, further subdivided into upper and lower sections. The dip angle and length of each row of deep boreholes were rationally determined. Specific blasting parameters for the deep boreholes were as follows: borehole diameter 67mm, 2-3 boreholes per row, row spacing 1.5m, 13 rows on the left and 15 rows on the right, totaling approximately 147 boreholes (33 on the upper left, 32 on the lower left, 43 on the lower right, and 39 on the upper right). The first row of boreholes was 1.5m from the central riser's resistance line. A blasting method was adopted, with simultaneous retreat from the center to both sides in both upper and lower sections, and the inter-row micro-difference time was set to 100ms.

[0039] S5 deep hole drilling construction: such as Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, parallel medium-deep holes are drilled downwards in the drilling roadway 6 at the top of the mining area, and parallel medium-deep holes are drilled upwards in the drilling roadway 5 at the bottom of the mining area. Then, a pneumatic charging machine is used to charge the medium-deep holes. The charging structure adopts an axially fully coupled form. The detonating charge is placed at the bottom of the hole, and the hole opening is sealed with a special plugging material with a plugging length of 1m.

[0040] S6 mining area recovery: such as Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, the central well 4 of the stope is used as the free face to provide compensation space for blasting. The mining is carried out by retreating to both sides. The blast holes near the central well 4 are blasted first to form slotting space. The entire stope can achieve the recovery of all ore through four blasts.

[0041] Rows numbered 1 to n (where n is a natural number greater than 1) are arranged sequentially from the central well 4 to both sides. In this embodiment, the left working area has rows 1 to 13, and the right working area has rows 1 to 15. The specific mining sequence is as follows: 1) The first blasting of the left side of the work area is carried out in two sections, with micro-differential blasting carried out simultaneously in the upper and lower sections to form a slotting space and remove all the ore; 2) In the second blasting, rows 3 to 7 on the left side of the work area were blasted synchronously with slight differential blasting in sections, yielding approximately 2 / 3 of the ore. 3) In the third blasting operation, rows 1 to 7 on the right side of the work area were blasted synchronously with slight differential blasting in sections, yielding approximately 2 / 3 of the ore. 4) The fourth blasting involves simultaneous micro-differential blasting in the upper and lower sections of rows 8-13 on the left side of the working area and rows 8-15 on the right side of the working area, to achieve the extraction of the remaining ore in one go and complete the mining of the mining area.

[0042] Ore extraction at S7 mining site: (e.g.) Figure 3 and Figure 4As shown, after each blast, the collapsed ore is shoveled out through the ore outlet tunnel 2, enters the stage transport tunnel 1, is concentrated in the ore bin through the ore pass 13, and is then lifted to the surface by the skip.

[0043] S8 Ground Pressure Management and Control: such as Figure 3 and Figure 4 As shown, after all the ore has been extracted, the ore extraction tunnel 2 is sealed off, and the goaf is cemented and filled to control the ground pressure in the goaf.

[0044] After all the ore in the mining area has been extracted, 3D scanning technology is used to obtain point cloud data of the goaf and calculate its volume to determine the amount of backfill material needed. A sealed concrete retaining wall is constructed at the junction of the ore extraction tunnel 2 and the mining area connecting tunnel, and drainage holes are installed. Subsequently, backfill pipelines are laid from the previous stage to carry out cemented backfilling of the goaf. The backfill material is a mixture of tailings cementitious material and waste rock.

[0045] During the mining process in the test stope, the exposed area of ​​the hanging wall rock was consistently less than 600 m². 2 Furthermore, the exposure time was relatively short, and no roof falls or large-scale collapses occurred during the test. The production capacity of the mining area increased from approximately 18 t / d to approximately 100 t / d, the amount of mining operations was significantly reduced, the ore dilution rate decreased from 40%–50% to approximately 15%, the recovery rate of fines was significantly improved, and the labor intensity of personnel was significantly reduced, achieving a simultaneous improvement in safety and economic benefits.

[0046] As can be seen from the above embodiments, the experimental stope was successfully mined by introducing the mining method described in this invention. This invention effectively solves the technical bottlenecks of high dilution, low efficiency, and poor safety in deep-hole mining of steeply inclined irregular thin veins by combining the boundary control advantages of shallow-hole ore retention method with the high-efficiency ore caving advantages of medium-deep hole. It has significant promotional value.

[0047] It should be noted that the above embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, those skilled in the art can make reasonable modifications or variations based on these embodiments without creative effort, and all such modifications or variations should be covered within the scope of protection of the present invention.

Claims

1. A method for two-section parallel medium-deep hole mining of low-lean ore veins with steep inclination and irregularity, characterized in that, Includes the following steps: Based on the occurrence and dip angle of the ore body, S1 is divided into stages along the vertical strike b. Within each stage, a stope is divided along the strike a of the ore body. Within the stope, two sub-sections are arranged along the vertical strike b. S2 is excavated along the strike a of the ore body in the footwall direction d. Multiple ore-exiting cross-vein roadways are excavated in the direction of the ore body within the stage transport cross-vein roadways. The ore-exiting cross-vein roadways are excavated until the ore body disappears. End ventilation shafts that serve as both exploration and ventilation are arranged at both ends of the stope. In the stage transport cross-vein roadways, connecting roadways and ore passes are excavated along the direction away from the ore body. S3 excavates a bottom vein drilling tunnel along the ore body strike a at the bottom of the stope, excavates a top vein drilling tunnel along the ore body strike at the top of the stope, and excavates a central riser extending along the ore body dip in the middle of the ore body. S4 determines the length of the ore body along the strike a of the ore body based on the bottom and top vein drilling tunnels, obtains the thickness of the ore body through the ore-exiting vein tunnel, and determines the height and dip of the ore body based on the end ventilation shaft and the central shaft, and comprehensively constructs a three-dimensional spatial model of the ore body; based on the three-dimensional spatial model of the ore body and ensuring that the blasting action range is limited to inside the ore body, the parameters for medium-deep hole blasting are determined. S5 drills parallel medium-deep holes downward in the rock drilling tunnel within the top vein, and drills parallel medium-deep holes upward in the rock drilling tunnel within the bottom vein. S6 uses the central well of the mining area as the free face and adopts the method of retreating to both sides for mining. First, the blast holes on both sides of the central well are blasted to form a slotting space. The S7 caving ore is shoveled out through the ore extraction channel and transported along the channel to the ore bin via the ore pass. It is then hoisted to the surface by a skip.

2. The method for two-section parallel medium-deep hole mining of low-lean ore veins with steep inclination and irregularity according to claim 1, characterized in that, In S1, the stage height is 35m to 40m, the segment height is 17.5m to 20m, and the stope length is no more than 50m.

3. The method for two-section parallel medium-deep hole mining of low-lean ore veins with steep inclination and irregularity according to claim 1, characterized in that, A support column is left between the S2 mining area and the pedestrian ventilation well at one end.

4. The method for two-section parallel medium-deep hole mining of low-lean ore veins with steep inclination and irregularity according to claim 1, characterized in that, In S3, the central skylight also serves as a cutting skylight; in S6, the central skylight also serves as a free surface.

5. The method for two-section parallel medium-deep hole mining of low-lean ore veins with steep inclination and irregularity according to claim 1, characterized in that, The mining area is divided into four working areas, namely the right upper mining area, the right lower mining area, the left upper mining area, and the left lower mining area, with the central well and the sub-sections as the boundaries.

6. The method for two-section parallel medium-deep hole mining of low-lean ore veins with steep inclination and irregularity according to claim 5, characterized in that, In the upper right and upper left mining areas, drill parallel medium-deep holes downward in the rock-drilling tunnels within the top veins, and in the lower right and lower left mining areas, drill parallel medium-deep holes upward in the rock-drilling tunnels within the bottom veins within the bottom veins.

7. The method for two-section parallel medium-deep hole mining of low-lean ore veins with steep inclination and irregularity according to claim 1, characterized in that, In S6, the mining method adopts the method of retreating towards the pedestrian ventilation shafts at both ends. The upper and lower sections are simultaneously blasted with micro-differential detonation. By controlling the sequence of micro-differential detonation, the lower section of the ore body collapses first, followed by the upper section of the ore body, so that the two sections of the ore body collapse sequentially in the same blasting process.

8. The method for two-section parallel medium-deep hole mining of low-lean ore veins with steep inclination and irregularity according to claim 1, characterized in that, It also includes the following steps: S8 Ground pressure management and control: After all the ore has been extracted, the ore extraction tunnel is sealed and the goaf is cemented and backfilled to achieve ground pressure control in the goaf.

9. A method for mining low-lean ore veins in two parallel medium-deep holes in steeply dipping, irregular thin veins according to claim 8, characterized in that... Before the cemented backfilling, the process also includes: performing a three-dimensional scan of the goaf, calculating the volume of the goaf based on point cloud data to determine the amount of backfilling material to be used; and constructing a sealed concrete retaining wall at the ore outlet cross-vein roadway and the bottom connecting roadway, and leaving drainage holes.

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