A method of mining steeply and inclined ore bodies
By using the reverse mining method, starting from the footwall of the ore body through slotting and blasting, and gradually retreating towards the hanging wall, the problems of difficult roadway formation and high costs caused by unstable rocks in the footwall of the ore body were solved, achieving efficient and low-cost ore recovery and economic benefits.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HEBEI PROVINCE FANSHAN PHOSPHORITE CO LTD
- Filing Date
- 2023-04-17
- Publication Date
- 2026-06-23
AI Technical Summary
When the footwall rock of the ore body is unstable, traditional mining methods lead to difficulties in roadway formation, large support engineering work, high roadway maintenance costs, and risks of ore loss and dilution, making it difficult to achieve efficient and low-cost mining.
The reverse mining method is adopted, starting from the footwall of the ore body with slotting blasting and gradually retreating towards the hanging wall. The preparatory and permanent works are arranged in the ore body or in the stable low-grade ore in the hanging wall. Slotting blasting is carried out using cutting shafts and footwall roadways to gradually widen the roadways, ensuring ore recovery rate and reducing roadway deformation.
It has achieved efficient and low-cost ore mining, reduced roadway maintenance costs and ore loss, improved the economic benefits of ore mining, and avoided engineering problems caused by unstable rocks in the lower roadway.
Smart Images
Figure CN116357320B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of mining technology, specifically a method for mining steeply inclined and inclined ore bodies. Background Technology
[0002] Among the three traditional mining methods—caving, open-cut mining, and backfilling—caving has the lowest mining ratio and cost, and the highest production efficiency. In the mining of gently dipping and thick dipping ore bodies, a common method is to gradually retreat from the hanging wall to the footwall through slotting blasting, a process known as "direct mining." Permanent works are placed in the footwall, requiring relatively stable rock. However, if the footwall rock is fractured, it is difficult to place works and form tunnels. Under such geological conditions, using the "direct mining" method results in slow tunnel excavation, long preparation time, high secondary support rates in the later stages of mining, deformation and necking of the ore access roadway in the footwall direction during later mining phases, increasing mining difficulty, and even causing collapses and ore loss at individual locations. Therefore, in complex environments where the ore body is moderately stable but the footwall rock is unstable, the mining of steeply dipping and extremely thick dipping ore bodies presents a contradictory balance between efficiency, safety, cost, dilution, and loss. Summary of the Invention
[0003] To address the above problems, this invention provides a mining method suitable for steeply inclined and inclined ore bodies. The method involves starting with trenching and blasting in the footwall of the ore body and then gradually retreating towards the hanging wall, a process referred to as "reverse mining." Each section of the preparatory work and permanent works are arranged within the ore body or in the low-grade ore within the hanging wall. This avoids the drawbacks of trenching and blasting from the hanging wall towards the footwall, such as the need to install permanent works in unstable rock sections of the footwall, large support works, high subsequent roadway maintenance costs, and high waste rock production rates. This method achieves high-efficiency, low-cost mining with minimal ore loss and dilution.
[0004] The objective of this invention is achieved through the following technical solution:
[0005] A mining method suitable for steeply dipping and inclined ore bodies: This method is suitable for mining steeply dipping and inclined ore bodies with a horizontal thickness greater than 20m, a long strike, good fluidity in the footwall direction, fractured rocks in the footwall with well-developed joints and fissures, making it difficult to arrange engineering works, relatively stable rocks in the ore body and hanging wall, and a distinct layered structure from the footwall to the hanging wall, resulting in significant differences in the mechanical strength of the ore body, interbedded rocks, and surrounding rocks of the top and bottom plates. In addition, low-grade ore is present in the hanging wall direction.
[0006] The ore blocks are arranged along the strike of the ore body, with a mining section height of 45-60m, a block length of 60-90m, and a block width equal to the horizontal thickness of the ore body. Three sub-sections and two intermediate sections are set up between each ore body at a vertical height of 45-60m: from top to bottom, these are intermediate section one, sub-section one, sub-section two, sub-section three, and intermediate section two. The distance between sub-sections is 12-15m, and the bottom plate of the first sub-section is 9-15m from the bottom plate of the first intermediate section.
[0007] Three sections are arranged between the first and second middle sections, namely the first section, the second section, and the third section from top to bottom. Within each section, there are section upper plate roadways, ore access roads, lower plate roadways, cutting shaft side roadways, cutting shafts, ore pass connecting roadways, inclined slope connecting roadways, section sedimentation roadways, ore block power distribution box chambers, and ventilation and pedestrian shaft connecting roadways. The first section should be arranged with a separate ore access roadway. When mining the ore block, upward deep holes are constructed in the ore access roadways, cutting shaft side roadways, and lower plate roadways. During mining, the cutting shaft located at the head of the cutting shaft side roadway is used as the free face to start slotting and blasting, and the mining width of the lower plate roadway is gradually increased to the required level. The mining of the lower plate roadway should be ahead of each ore access roadway. Each ore access roadway is mined from the free face formed after the blasting of the lower plate roadway. The first and second intermediate sections are connected to the first, second, and third sections by ramps. The ramps and the upper roadways of the first and second sections should be located outside the rock movement angle after the last row of deep holes in the third section, close to the stable position of the ore body on the hanging wall. The upper roadway of the third section is 25m away from the last row of deep holes in the third section at a horizontal distance to ensure that the loader can enter the ore exit roadway after the last row of deep holes is blasted.
[0008] The first intermediate section is located above the first sub-section, with a vertical distance of 9-15 meters. A pass will be constructed from the second intermediate section to the first intermediate section for use in the later stages of mining preparation and ore extraction in the first intermediate section. A ventilation and personnel shaft will be constructed from the first sub-section to the first intermediate section. The ventilation and personnel shaft will connect with the inclined connecting roadway in the intermediate section, serving as a channel for the removal of toxic and harmful gases during blasting and as a safety exit.
[0009] The second section is located below the third section, at a vertical distance of 12-15 meters. A pass will be constructed from the second section to each of the first, second, third, and fourth sections for use during mining preparation and ore extraction. A ventilation and personnel shaft will be constructed from the second section to the third section to facilitate the removal of toxic and harmful gases during blasting and as a safety exit. Tracks and cables will be laid and strung along the upper and lower footwall transport roadways and through the vein in the second section. Locomotives will pull mine cars from the passes through the ore passes, fed by ore feeders. During mining between the floor of the second and third sections, a loader will scoop ore from the third section into the passes of the second section.
[0010] Preferably, segmented hanging wall roadways are arranged along the strike of the ore body in the hanging wall of the first, second, and third sections. The segmented hanging wall roadways of the first and second sections are located outside the rock movement angle after the last row of deep boreholes in the third section on the hanging wall side. The segmented hanging wall roadway of the third section is 25m horizontally away from the last row of deep boreholes in this section. At the boundary of the hanging wall of the first section, another ore-exit connecting roadway is arranged along the strike of the ore body, 15m horizontally away from the last row of deep boreholes in the first section. The main purpose is to utilize the ore-exit connecting roadway... The mine connecting roadway leads to the lower plate roadway, where various ore exit routes are constructed to reduce the length of the ore exit routes and save on engineering work. For each ore block, a block connecting roadway is constructed from the ore exit connecting roadway to the upper plate roadway, connecting the upper plate roadway and the ore exit connecting roadway to facilitate the access of equipment and personnel. In the segmented upper plate roadway, segmented sedimentation roadways, ore block power distribution box chambers, ventilation and water pipelines, and power supply facilities are arranged. The segmented sedimentation roadways are used to settle deep hole construction and roadway wastewater during ore extraction. From the segmented upper plate roadway, ore pass connecting roadways and ore pass connections are constructed to form the slag removal conditions for the construction of each segment of the mining preparation project.
[0011] Preferably, segmented lower plate roadways are arranged along the strike of the ore body at the lower plate boundaries of the first, second, and third segments. In the second and third segments, the segmented lower plate roadways and segmented upper plate roadways are connected by ore extraction access roads. In the first segment, an additional ore extraction connecting roadway is arranged along the strike of the ore body at the upper plate boundary. The ore extraction connecting roadway and the lower plate roadway are connected by ore extraction access roads. The spacing between ore extraction access roads is 12-18m, and the ore extraction access roads between the upper and lower segments are arranged in a diamond pattern. Next, construct the cutting shaft ear tunnel from the lower side roadway towards the lower side roadway. The cutting shaft ear tunnel is constructed to the lower side roadway mining boundary line. During the mining of the ore block, a cutting shaft is formed from the head of the cutting shaft ear tunnel using one-time shaft-forming blasting technology. After the cutting shaft is formed, slotting blasting is carried out using the upward deep holes arranged in the cutting shaft ear tunnel and the lower side roadway on both sides of the cutting shaft ear tunnel to gradually widen the mining width. After the mining width of the lower side roadway reaches the mining boundary line of the ore exit, each ore exit can start blasting mining using the free face formed after the mining of the lower side roadway, and gradually retreat mining from the lower side roadway to the upper side roadway.
[0012] Preferably, each segment is arranged with ore blocks along the strike of the ore body. The length of each ore block is 60-90m, and the width is equal to the horizontal thickness of the ore body. During the mining of each ore block, blasting begins first at the cutting shaft located in the side shaft of the lower footing. The lower footing is mined first. After the mining width of the lower footing reaches the mining boundary of the ore extraction route, each ore extraction route can begin blasting mining using the free face formed after the mining of the lower footing. Mining proceeds gradually from the lower footing towards the hanging wall. Each ore block includes one cutting channel and four channels (numbered 1, 2, 3, and 4 respectively), for a total of five ore extraction routes. The mining width controlled by each ore extraction route is 12-18 meters, and the total mining width of the five ore extraction routes is 60-90 meters, which is the length of one ore block. When mining a block, mining should proceed gradually from one end of the block to the other end in a 4-way direction. The mining positions of two adjacent mining access routes should be staggered by a certain distance to form a stepped mining line for each mining access route within the block. This allows the ground pressure to be released gradually, preventing concentrated ground pressure from damaging the mining access routes, increasing the difficulty of mining, and increasing the cost of secondary maintenance of the roadway.
[0013] Preferably, four ore passes are arranged within the first (or second) intermediate section. The ore pass from the intermediate section to the previous intermediate section is numbered 1, the ore pass from the intermediate section to the first sub-section is numbered 2, the ore pass from the intermediate section to the second sub-section is numbered 3, and the ore pass from the intermediate section to the third sub-section is numbered 4. The ore passes are connected to the hanging wall transport roadway, the sub-section hanging wall roadway, and the ore extraction connecting roadway within the intermediate section (sub-section) through ore pass connecting roadways, ensuring that each intermediate section or sub-section has at least one ore pass for use during the preparatory mining construction and subsequent blasting and mining.
[0014] Preferably, during the mining of the first, second, and third sections, the second section serves as the main transportation channel for storing and transporting ore from the first, second, and third sections. After laying tracks and erecting lines in the hanging wall haulage roadway, footwall haulage roadway, and cross-cutting in the second section, electric locomotives pull mine cars from the ore pass and feed ore through the ore feeder. When the first, second, and third sections are mined to a certain position, and the ore passes from the second section to the first, second, and third sections are no longer in use, the mining of the second section can begin. During the mining of the second section, a loader shovels the ore into the ore pass from the second section to the third section.
[0015] Preferably, the first, second, and third sections must adhere to a top-down mining sequence. When mining two sections simultaneously, the upper section should advance the lower section by a distance that ensures the upper section remains outside the displacement range of the lower section's mining face, and is no less than 20 meters ahead. The upward deep boreholes located in the lower section's footwall and their footwall mining boundaries should be close to the upper section's (middle section's) footwall mining boundary to ensure full ore recovery and prevent ore loss. The side borehole angles of the footwall deep boreholes located in the footwall should be consistent with the dip angle of the ore body's footwall to prevent ore loss and avoid over-mining of the footwall surrounding rock, which could lead to dilution.
[0016] Preferably, during blasting at each step in the middle section (segment), the depth of the upward-facing deep hole in this segment (middle section) should be designed based on the outline of the already mined upper middle section (segment) to prevent the protective layer at the bottom of the hole from being too thick or too thin, which would affect the blasting effect. During each step blast, the amount of ore to be blasted at this step should be calculated based on the ore blasting area and ore blasting thickness. After blasting, the amount of ore to be blasted at each step should be controlled according to the determined ore extraction ratio to ensure that no ore is lost in the stope, while also creating compression blasting conditions for subsequent step blasting. The five ore extraction routes in each block are blasted alternately until the ore in one segment is completely mined.
[0017] Preferably, at the end of each ore block, a ventilation manhole is constructed from the middle upper hanging wall along the haulage roadway or the segmented upper hanging wall along the haulage roadway upwards to the segmented upper hanging wall along the haulage roadway or the middle upper hanging wall along the haulage roadway. The ventilation manhole is connected to the segmented upper hanging wall along the haulage roadway or the middle upper hanging wall along the haulage roadway through the ventilation manhole.
[0018] The beneficial effects of this invention are:
[0019] 1. This invention starts with trenching and blasting in the footwall of the ore body and gradually retreats towards the hanging wall. The preparatory works for each section of the mining, as well as permanent works such as ramps, sedimentation tunnels, and ventilation shafts, are all arranged in the ore body or in the low-grade ore with stable rock in the hanging wall direction. This can avoid the problems of long preparation time for mining, high difficulty in tunnel excavation and support, and high construction costs caused by arranging permanent works in unstable rock sections of the footwall.
[0020] 2. This invention starts with trenching and blasting from the footwall of the ore body and then gradually retreats towards the hanging wall. It first mines the unstable rock in the footwall and then gradually mines the stable rock in the hanging wall, which reduces the cost of secondary maintenance of the roadway in the later stage and avoids the problem of loss of ore due to roadway deformation and collapse.
[0021] 3. In this invention, each segment of the lower plate roadway is located at the lower plate boundary of the ore body. The angle of the deep hole and the side hole of the lower plate roadway are consistent with the dip angle of the lower plate of the ore body. The lower plate roadway utilizes the lower plate roadway and the cutting ear roadway and cutting shaft constructed from the lower plate roadway for slotting blasting. Except for the slotting position of the cutting shaft, no waste rock is mined at the mining boundary line of the lower plate roadway, resulting in a low dilution rate. All other projects are arranged in the ore body or in the low-grade ore in the direction of the hanging wall of the ore body. During the construction of the mining preparation project, all the ore is mined. This avoids the defects of high waste rock output caused by arranging permanent projects from the lower plate roadway and arranging some ore access roads (rock drilling roadways) in the waste rock of the lower plate roadway, which can improve the economic benefits of the ore.
[0022] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the process flow of the optimized mining method of the present invention.
[0024] Figure 2 for Figure 1 Sectional view along line I-I.
[0025] Figure 3 for Figure 1 Sectional view along line II-II.
[0026] Figure 4 for Figure 1 Sectional view along line III-III.
[0027] Figure 5 for Figure 1 Sectional view along line IV-IV.
[0028] Figure 6 for Figure 1 Sectional view along line V-V.
[0029] In the picture: 1—Transportation tunnel along the upper plate of the second middle section; 2—Transportation tunnel along the lower plate of the second middle section.
[0030] 3—Sectional sedimentation tunnel; 4—Inclined ramp
[0031] 5—Sectional upper access roadway; 6—Sectional inclined connecting roadway
[0032] 7—Mine access road; 8—First section lower roadway
[0033] 9—Second Section Lower Track; 10—Third Section Lower Track
[0034] 11—Transportation lane along the upper plate of section 1; 12—Transportation lane along the lower plate of section 1.
[0035] 13—Rock movement angle; 14—Last row of deep holes
[0036] 15—Intermediate section cross-vein tunnel; 16—Ore body boundary line
[0037] 17—Ore pass chute chamber; 18—Ore pass
[0038] 19—Mine Block Connector 20—Mine Exit Access Route
[0039] 21—Liujing Lianxiang; 22—Erzhongduan Chuanmaixiang
[0040] 23—Upward deep hole; 24—Cut ear alley
[0041] 25—Cutting Shaft; 26—Ore Block Distribution Box Chamber
[0042] 27—Boundary line of the approach roadway mining; 28—Boundary line of the lower roadway mining.
[0043] 29—Mid-section inclined roadway connecting roadway; 30—Each ore entry roadway retreat step line within the ore block.
[0044] 31—Deep hole and side hole in the lower tunnel; 32—Ventilation and pedestrian well
[0045] 33—Ventilated Pedestrian Well Connecting Lanes Detailed Implementation
[0046] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0047] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.
[0048] See Figures 1 to 6 , Figure 1 This is a schematic diagram of the optimized mining method of the present invention (mainly reflecting the interrelationship of the first section, the first segment, the second segment, the third segment, and the second section along the vertical direction of the ore body on the vertical plane, the position and occurrence state of the upper and lower walls of the ore body, the horizontal thickness of the ore body, the position of the lower wall roadway, the upper wall roadway of each segment, the ore extraction connecting roadway of the first segment, the side hole of the lower wall roadway, the width of the slot, the boundary line 16 of the ore body and the mining boundary line).
[0049] Figure 2 for Figure 1The sectional view along line I-I (mainly reflects the positional relationship of the lower plate roadway, cutting side roadway, upper plate roadway, sedimentation roadway, segmented inclined connecting roadway 6, ventilation and pedestrian shaft, ore pass, ore extraction connecting roadway, ore extraction access road (rock drilling roadway), and access road mining boundary line 27 in the first section within the first section, as well as their positional relationship from the construction of the second intermediate section to the ore pass of the first section)
[0050] Figure 3 for Figure 1 The sectional view of line II-II (mainly reflects the positional relationship of the lower plate roadway, cutting side roadway, upper plate roadway, sedimentation roadway, segmented inclined connecting roadway 6, ventilation and pedestrian shaft, ore pass, ore exit roadway (rock drilling roadway), and roadway mining boundary line 27 in the second section within the second section, as well as the positional relationship from the construction of the second middle section to the ore pass of the second section)
[0051] Figure 4 for Figure 1 The sectional view of line III-III (mainly reflects the positional relationship of the lower plate roadway, cutting side roadway, upper plate roadway, sedimentation roadway, segmented inclined connecting roadway, ventilation and pedestrian shaft, ore pass, ore access road (rock drilling roadway), and access road mining boundary line in the plane, as well as the positional relationship with the ore pass from the construction of the second section to the third section)
[0052] Figure 5 for Figure 1 The sectional view along line IV-IV (mainly reflects the positional relationship of the upper hanging wall transport roadway, inclined connecting roadway, lower hanging wall transport roadway, cross-vein roadway, ore pass, ventilation and pedestrian shaft, middle section inclined connecting roadway 29, and ore pass ore discharge machine chamber 17 in the plane, as well as their positional relationship from the construction of the second middle section to the first section, second section, third section, and first middle section ore pass)
[0053] Figure 6 for Figure 1 The V-V line cross-sectional view (mainly reflects the positional relationship of various projects arranged in the first, second, third and second sections along the strike of the ore body on the vertical elevation; the ore access roads (drilling tunnels) in the first, second and third sections should be arranged in a diamond shape; the mining width controlled by each ore access road (drilling tunnel) along the strike of the ore body is 12 meters; the side hole angle of the drilling tunnel is 50°)
[0054] This invention is applicable to ore bodies with a horizontal thickness greater than 20m, long strike of the ore body, good ore flowability in the footwall direction, broken rocks in the footwall with well-developed joints and fissures, making it difficult to arrange engineering works, relatively stable ore body and hanging wall rocks, obvious layered structure from the footwall to the hanging wall, resulting in significant differences in mechanical strength between the ore body, interbedded rocks and the surrounding rocks of the top and bottom plates, and low-grade ore is present in the hanging wall direction.
[0055] Figures 1-6This is a schematic diagram of the mining method process of the present invention. First, an ellipsoidal ore-feeding model is established based on the ore properties, block size, viscosity, and dip angle. Numerical simulation is performed using this model, and the segment height and the spacing of the ore-feeding access roads (drilling tunnels) are calculated in conjunction with the drilling equipment capacity. Then, based on the segment elevations, the lower wall tunnels for the first, second, and third segments are respectively arranged. The location of the last row of deep holes 14 is determined in the hanging wall direction of the third segment. The last row of deep holes 14 is determined according to the principle of mining 50% of the ore body at the bottom and 50% of the low-grade ore at the top. The locations of the upper wall tunnels for the first and second segments are determined based on the rock movement angle 13 after mining the last row of deep holes in the third segment. The upper wall tunnel 5 for each segment is arranged in the direction of the rock movement angle 13 towards the hanging wall. The horizontal distance between the upper wall tunnel 5 of the third segment and the last row of deep holes in this segment is 25m. At the boundary of the hanging wall of the first section of the ore body, another ore-exit connecting tunnel 7 is arranged along the strike of the ore body. The ore-exit connecting tunnel 7 is 15m away from the last row of deep holes in the first section.
[0056] The middle section is 45m high, the ore block is 60m long, and the width is equal to the horizontal thickness of the ore body; three sub-sections and two middle sections are set between the ore bodies with a vertical height of 45m: from top to bottom, they are Middle Section 1, Sub-Section 1, Sub-Section 2, Sub-Section 3, and Middle Section 2; the distance between the sub-sections is 12m, and the distance between the bottom plate of Sub-Section 1 and the bottom plate of Middle Section 1 is 9m. (See...) Figure 1 )
[0057] The first and second middle sections are connected to the first, second, and third sections by ramp 4 and the segment ramp connecting roadway 6. The ramp 4 and the upper plate roadway 5 of the first and second sections are located outside the rock movement angle 13 after the last row of deep holes 14 in the third section, close to the stable position of the ore body on the hanging wall side. The upper plate roadway of the third section is 25m away from the last row of deep holes 14 in the third section at a horizontal distance of 25m, to ensure that the loader can enter the ore exit roadway 20 to exit the ore after the last row of deep holes is blasted.
[0058] Section 1 is located above Section 1, with a vertical distance of 9 meters. A 18-meter chute is constructed from Section 2 to Section 1. Figure 1 The first section has a ore pass (18), below which is the ore pass chute chamber 17, used for the later stages of the first section's mining preparation and ore extraction. A ventilation and pedestrian shaft 32 is constructed from the first section to the first section. The ventilation and pedestrian shaft connects to the inclined roadway in the first section, serving as a channel for the removal of toxic and harmful gases during ore block blasting and as a safety exit.
[0059] The second section is located 12 meters below the third section. A pass 18 is constructed from the second section towards the first, second, third, and fourth sections. Below the pass 18 is the ore feed chamber 17, used for preparatory work and ore extraction. A ventilation and personnel shaft 32 is constructed from the second section towards the third section, serving as a passage for removing toxic and harmful gases during blasting and as a safety exit. Tracks and cables are laid and strung in the upper hanging wall transport roadway 1, lower hanging wall transport roadway 2, and cross-cutting 22 of the second section. Locomotives pull mine cars from the pass 18 via the ore feed machine. During mining between the floor of the second section and the floor of the third section, a loader moves the ore from the third section into the pass 18 of the second section.
[0060] In the first, second, and third sections of the ore body, a segmented hanging wall roadway 5 is arranged along the strike of the ore body. The segmented hanging wall roadways 5 in the first and second sections are located beyond the rock movement angle 13 after the last row of deep boreholes in the third section on the hanging wall side. The segmented hanging wall roadway 5 in the third section is 25m horizontally away from the last row of deep boreholes in this section. At the boundary of the hanging wall of the first section, another ore access road 7 is arranged along the strike of the ore body. The ore access road 7 is 15m horizontally away from the last row of deep boreholes in the first section. The main purpose of the ore access road 7 is to provide access to the first section. Construction of each ore access road 20 in the lower plate roadway 8 is carried out to reduce the length of the ore access road 20 and save on the amount of work. For each ore block, a ore block connecting road 19 is constructed from the ore block connecting roadway 7 to the upper plate roadway 5 to connect the upper plate roadway and the ore block connecting roadway, facilitating the access of equipment and personnel. In the segmented upper plate roadway 5, segmented sedimentation roadway 3, ore block power distribution box chamber 26, ventilation and water pipelines and power supply facilities are arranged. The segmented sedimentation roadway 3 is used to settle sewage from deep hole construction and roadway during ore extraction. The chute connecting roadway 21 and chute 18 are constructed from the segmented upper plate roadway 5 to form the slag removal conditions for the construction of each segmented mining preparation project.
[0061] Along the ore body strike, the first section lower footwall roadway 8, the second section lower footwall roadway 9, and the third section lower footwall roadway 10 are arranged along the footwall boundary of the first, third, and fourth sections. Within the second and third sections, the second section lower footwall roadway 9, the third section lower footwall roadway 10, and the section upper footwall roadway 5 are connected by an ore extraction access roadway 20. At the footwall boundary of the first section, another ore extraction connecting roadway 7 is arranged along the ore body strike. This connecting roadway 7 is connected to the first section lower footwall roadway 8 by the ore extraction access roadway 20. The spacing between the ore extraction access roads (drilling roadways) is 12m. The ore extraction access roads 20 between the upper and lower sections are arranged in a diamond pattern. Figure 6(As shown). Then, from the first section lower plate roadway 8, the second section lower plate roadway 9, and the third section lower plate roadway 10, construct the cutting shaft side roadway 24 towards the lower plate. The cutting shaft side roadway 24 is constructed to the lower plate roadway mining boundary line 28. During block mining, a cutting shaft 25 is formed from the head of the cutting shaft side roadway 24 using a one-time shaft-forming blasting technique. After the cutting shaft is formed, utilize the lower plate roadways arranged on both sides of the cutting shaft side roadway 24 (first section lower plate roadway 8, second section lower plate roadway 9, and third section lower plate roadway 10). In the upper deep hole 23 within 0), slotting blasting is carried out to gradually widen the mining width. After the mining width of the lower roadway (first section lower roadway 8, second section lower roadway 9, third section lower roadway 10) reaches the mining boundary line 27 of the ore exit 20, each ore exit 20 can start blasting mining using the free face formed after mining in the lower roadway (first section lower roadway 8, second section lower roadway 9, third section lower roadway 10), and gradually retreat mining from the lower side to the upper side.
[0062] Each section has ore blocks arranged along the strike of the ore body. The ore blocks are 60m long and the width is equal to the horizontal thickness of the ore body. When mining each ore block, blasting begins at the cutting shaft 25 located in the side shaft 24 of the lower roadway (lower roadway 8 of the first section, lower roadway 9 of the second section, and lower roadway 10 of the third section). The lower roadway is mined first. After the mining width of the lower roadway reaches the mining boundary line 27 of the ore access road 20, each ore access road 20 can start blasting mining using the free face formed after mining the lower roadway (lower roadway 8 of the first section, lower roadway 9 of the second section, and lower roadway 10 of the third section). Mining gradually moves from the lower side to the upper side. Each ore block includes one cutting channel and four channels (numbered 1, 2, 3, and 4), totaling five ore access routes 20. Each ore access route 20 controls a mining width of 12 meters, for a total mining width of 60 meters, which is the length of one ore block. During mining, mining proceeds gradually from one end of the cutting channel towards the other end (channel 4). The mining positions of adjacent ore access routes 20 are staggered by a certain distance, forming a stepped retreat line 30 for each ore access route within the block. This allows for gradual release of ground pressure, preventing concentrated ground pressure from damaging the ore access routes 20, increasing mining difficulty, and raising secondary maintenance costs for the roadways.
[0063] Four ore passes (18 in total) are arranged within the second section. The ore pass from the second section to the first section is numbered 1, the ore pass from the second section to the first sub-section is numbered 2, the ore pass from the second section to the second sub-section is numbered 3, and the ore pass from the second section to the third sub-section is numbered 4. The ore passes (18 in total) are connected to the upper plate transport roadway, the sub-section upper plate roadway 5, and the ore extraction connecting roadway 7 in the first section (sub-section) through the ore pass connecting roadway 21, ensuring that each section or sub-section has at least one ore pass for use in the preparatory mining construction and subsequent blasting and mining.
[0064] During the mining of the first, second, and third sections above, the second section serves as the main transportation channel for storing and transporting ore from the first, second, and third sections above. After laying tracks and stringing wires in the upper hanging wall haulage roadways of the second section, the upper hanging wall haulage roadway of the first section 11, the lower hanging wall haulage roadway of the second section 2, the lower hanging wall haulage roadway of the first section 12, the cross-cutting roadway of the second section 22, and the cross-cutting roadway of the first section 15, ore is transported from the ore pass 18 to the ore feeder by electric locomotives. When the mining of the first, second, and third sections above reaches a certain position, and the ore pass 18 from the construction of the second section to the first, second, and third sections is no longer in use, the mining of the second section can begin. During the mining of the second section, the loader shovels the ore into the ore pass 18 from the construction of the second section to the third section.
[0065] The first, second, and third sections must adhere to a top-down mining sequence. When mining two sections simultaneously, the upper section should advance the lower section by a distance that ensures the upper section remains outside the displacement range of the lower section's mining face, and is no less than 20 meters ahead. The upward deep borehole 23 located in the lower section's lower sidewall roadway 9 and its lower sidewall roadway mining boundary line 28 should be close to the mining boundary line 28 of the first lower sidewall roadway 8 in the upper section to ensure full ore recovery and prevent ore loss. The angle of the side borehole 31 in the lower sidewall roadways (lower sidewall roadway 8 in the first section, lower sidewall roadway 9 in the second section, and lower sidewall roadway 10 in the third section) should be consistent with the dip angle of the footwall of the ore body to prevent ore loss and avoid over-mining of the surrounding rock in the lower sidewall roadways, which could lead to dilution.
[0066] When blasting at each step in the middle section (segment), the depth of the upward deep hole 23 should be designed according to the outline of the already mined upper middle section (segment) to prevent the protective layer at the bottom of the hole from being too thick or too thin, which would affect the blasting effect. When blasting at each step, the amount of ore to be blasted at this step should be calculated according to the ore blasting area and ore blasting thickness. After blasting, the amount of ore to be blasted at each step should be controlled according to the determined ore extraction ratio to ensure that no ore is lost in the stope, and at the same time, to create the conditions for compression blasting in the subsequent steps. The five ore extraction roads (rock drilling tunnels) in each block should be blasted alternately until the ore of one segment is mined out.
[0067] At the end of each block, a ventilation manhole 32 is constructed from the middle upper plate along the vein transport roadway 1 or the segmented upper plate roadway 5 upwards to the segmented upper plate roadway 5 or the middle upper plate along the vein transport roadway 1. The ventilation manhole 32 is connected to the segmented upper plate roadway 5 or the middle upper plate along the vein transport roadway 1 through the ventilation manhole, serving as a channel for the removal of toxic and harmful gases during the block blasting and as a safety exit.
[0068] This invention employs a reverse mining sequence, moving from the footwall to the hanging wall, which offers the following advantages:
[0069] 1. This invention starts with trenching and blasting in the footwall of the ore body and gradually retreats towards the hanging wall. The preparatory works for each section of the mining, as well as permanent works such as ramps, sedimentation tunnels, and ventilation shafts, are all arranged in the ore body or in the low-grade ore with stable rock in the hanging wall direction. This can avoid the problems of long preparation time for mining, high difficulty in tunnel excavation and support, and high construction costs caused by arranging permanent works in unstable rock sections of the footwall.
[0070] 2. This invention involves starting with trenching and blasting in the footwall of the ore body and then gradually retreating towards the hanging wall. It first mines the less stable ore body in the footwall direction and then gradually mines the more stable ore body in the hanging wall direction, reducing the cost of secondary maintenance of the roadways later. It also avoids the loss of ore volume caused by roadway deformation and collapse.
[0071] 3. In this invention, each segment of the lower plate roadway is located at the lower plate boundary of the ore body. The angle of the deep hole and the side hole of the lower plate roadway are consistent with the dip angle of the lower plate of the ore body. The lower plate roadway utilizes the lower plate roadway and the cutting ear roadway and cutting shaft constructed from the lower plate roadway for slotting blasting. Except for the slotting position of the cutting shaft, no waste rock is mined at the mining boundary line of the lower plate roadway, resulting in a low dilution rate. All other projects are arranged in the ore body or in the low-grade ore in the direction of the hanging wall of the ore body. During the construction of the mining preparation project, all the ore is mined. This avoids the defects of high waste rock output caused by arranging permanent projects from the lower plate roadway and arranging some ore access roads (rock drilling roadways) in the waste rock of the lower plate roadway, which can improve the economic benefits of the ore.
[0072] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.
Claims
1. A method for mining steeply dipping and inclined ore bodies, wherein the ore body is a steeply dipping and inclined ore body with a horizontal thickness greater than 20m, the ore body has a long strike, the ore has good flowability in the footwall direction, the footwall rock is fractured and difficult to arrange engineering, the ore body and the footwall rock are relatively stable, and low-grade ore is present in the footwall direction; characterized in that: The ore blocks are arranged along the strike of the ore body, with a mining section height of 45-60m, a length of 60-90m, and a width equal to the horizontal thickness of the ore body. Three sub-sections and two intermediate sections are set up between each ore body at a vertical height of 45-60m: from top to bottom, these are intermediate section one, sub-section one, sub-section two, sub-section three, and intermediate section two. The distance between sub-sections is 12-15m, and the distance between the bottom plate of the first sub-section and the bottom plate of the first intermediate section is 9-15m. Within the first, second, and third sections, sectional upper access roadways, ore access roads, lower access roadways, cutting shaft side roadways, cutting shafts, ore pass connecting roadways, and inclined slope connecting roadways are arranged. Sectional sedimentation roadways, ore block power distribution box chambers, and ventilation and pedestrian shaft connecting roadways are also arranged. In the first section, a separate ore access roadway is arranged. When mining the ore block, upward deep holes are constructed in the ore access roadways, cutting shaft side roadways, and lower access roadways. During mining, the cutting shaft located at the head of the cutting shaft side roadway is used as the free face to start slotting blasting. The mining of the lower access roadway should be carried out in advance of each ore access roadway. Each ore access roadway is mined from the free face formed after the blasting of the lower access roadway. The first and second middle sections are connected to the first, second and third sections by ramps. The ramps and the upper roadways of the first and second sections are located outside the rock movement angle after the last row of deep hole blasting in the third section, close to the stable position of the ore body on the hanging wall. The second section is located below the third section, with a vertical distance of 12-15 meters. A ore pass is constructed from the second section to the first section, the second section, the third section, and the first section. After laying tracks and stringing wires in the upper plate along the vein transport roadway, the lower plate along the vein transport roadway, and the cross vein roadway in the second section, the ore is transported from the ore pass to the mine cars by electric locomotives through the ore feeder. In the first, second, and third sections, each ore block is mined by blasting starting from the cutting shaft located in the side roadway. The side roadway is mined first, and after the width of the side roadway reaches the boundary of the ore access road, each ore access road begins blasting and mining using the free face formed after the side roadway mining. Mining proceeds from the side roadway towards the hanging wall. Each ore block includes one cutting channel and four channels, totaling five ore access roads. The mining width of each ore access road is controlled at 12-18 meters along the ore body strike, with a total mining width of 60-90 meters for the five ore access roads. During the mining of the ore block, mining proceeds from one end of the cutting channel towards the other end of the four channels. The mining positions of adjacent ore access roads should be staggered to form a stepped mining line for each ore access road within the ore block, so that the ground pressure is gradually released and the concentrated ground pressure does not damage the ore access roads.
2. The mining method applicable to steeply dipping and inclined ore bodies according to claim 1, characterized in that, In the first, second, and third sections of the ore body, segmented hanging wall roadways are arranged along the strike of the ore body. The segmented hanging wall roadways of the first and second sections are located outside the rock movement angle after the last row of deep holes in the third section is mined on the hanging wall side. The segmented hanging wall roadway of the third section is 25m horizontally away from the last row of deep holes in this section. At the boundary of the hanging wall of the first section, another ore extraction connecting roadway is arranged along the strike of the ore body. The ore extraction connecting roadway is 15m horizontally away from the last row of deep holes in the first section. Ore extraction routes are constructed from the ore extraction connecting roadway to the lower hanging wall roadway to reduce the length of the ore extraction routes. For each ore block, a ore block connecting roadway is constructed from the ore extraction connecting roadway to the upper hanging wall roadway to connect the upper hanging wall roadway and the ore extraction connecting roadway, facilitating the access of equipment and personnel. Segmented sedimentation roadways, ore block power distribution box chambers, ventilation and water pipelines, and power supply facilities are arranged in the segmented hanging wall roadways. Pass connecting roadways and pass connections are constructed from the segmented hanging wall roadways to form the conditions for slag removal during the preparation of mining in each section.
3. The mining method applicable to steeply dipping and inclined ore bodies according to claim 1, characterized in that, In the first, second, and third sections of the ore body, segmented footwall roadways are arranged along the strike of the ore body at the footwall boundary. Then, cutting shaft side roadways are constructed from the footwall roadways. The cutting shaft side roadways are constructed to the footwall roadway mining boundary line. During the mining of the ore block, a cutting shaft is formed from the head of the cutting shaft side roadway using one-time shaft-forming blasting technology. After the cutting shaft is formed, slotting blasting is carried out using the upward deep holes arranged in the cutting shaft side roadway and the footwall roadways on both sides of the cutting shaft side roadway to gradually widen the mining width. After the footwall roadway mining width reaches the mining boundary line of the ore access road, each ore access roadway begins blasting mining using the free face formed after the footwall roadway mining, and mining gradually retreats from the footwall direction to the hanging wall direction.
4. The mining method applicable to steeply dipping and inclined ore bodies according to claim 1, characterized in that, The first, second, and third sections must be mined in a top-down sequence. When two sections are mined simultaneously, the upper section should lead the lower section. The lead distance should be such that the upper section is outside the displacement range of the lower section's mining face and not less than 20m.
5. The mining method applicable to steeply dipping and inclined ore bodies according to claim 1, characterized in that, The center distance between the ore access roads of the first, second, and third sections is 12-18 meters, and the length of the cutting shaft side tunnel is 10-12 meters. Cutting shafts are arranged at the boundary line of the lower plate roadway of the cutting shaft side tunnel, and the angle of the deep hole side hole in the lower plate roadway is consistent with the dip angle of the ore body.
6. The mining method applicable to steeply dipping and inclined ore bodies according to claim 1, characterized in that, The upward deep boreholes arranged in the lower section of the lower roadway and the mining boundary line of the lower roadway are close to the mining boundary line of the lower roadway in the middle section of the upper section.
7. The mining method applicable to steeply dipping and inclined ore bodies according to claim 1, characterized in that, Four ore passes are arranged within the first or second intermediate section. The ore pass from the intermediate section to the previous intermediate section is numbered 1, the ore pass from the intermediate section to the first sub-section is numbered 2, the ore pass from the intermediate section to the second sub-section is numbered 3, and the ore pass from the intermediate section to the third sub-section is numbered 4. The ore passes are connected to the upper plate transport roadway of the intermediate section, the upper plate roadway of the sub-section, and the ore extraction connecting roadway through ore pass connecting roadways, ensuring that there is at least one ore pass in each intermediate section or sub-section for use in the preparatory mining construction and subsequent blasting and mining.
8. A method for mining steeply dipping and inclined ore bodies according to claim 1, characterized in that, During the mining of the first, second, and third sections, the first or second section serves as the main channel for storing and transporting ore from the three sections. After laying tracks and stringing wires in the upper, lower, and cross-vein transport roadways of the first or second section, ore is transported from the ore pass to the ore chute by electric locomotives and fed by ore feeders. When the three sections have been mined to the designated position and the ore pass from the first or second section to each section is no longer in use, the mining of the first or second section begins. During the mining of the first or second section, a loader shovels the ore into the ore pass from the second or third section to the first or second section.
9. The mining method applicable to steeply dipping and inclined ore bodies according to claim 1, characterized in that, When blasting at each step in the first or second intermediate section, the depth of the upward deep hole in this section or intermediate section should be designed according to the outline of the already mined upper intermediate section or segment to prevent the protective layer at the bottom of the hole from being too thick or too thin, which would affect the blasting effect. When blasting at each step, the amount of ore to be blasted at this step should be calculated according to the ore blasting area and ore blasting thickness. After blasting, the amount of ore to be blasted at each step should be controlled according to the determined ore extraction ratio to ensure that no ore is lost in the stope, and at the same time, to create the conditions for compression blasting in subsequent steps. The five ore extraction paths in each block should be blasted alternately until the ore in one segment is mined out.