A mining method suitable for "deep well" or "three-down" underground metal ore bodies

Abstract

The present invention relates to a mining method suitable for "deep well" or "three-down" underground metal ore bodies, belonging to the field of mining technology. The present invention adopts one- and two-step stopes for continuous mining, and is suitable for mining ore bodies under "deep well" high stress or "three-down" conditions. The ore body is first divided into stages, and the stages are divided into segments along the vertical height. The ore body is divided into ore blocks along the ore body strike within the stages and segments. The ore blocks are divided into one-step stopes and two-step stopes. The stopes are mined and filled in layers within each segment. The stopes are arranged according to the principle that the length direction of the stope is perpendicular to the main direction of the ground stress. Adjacent two-step stopes are arranged in a staggered manner, and the one-step stope is ahead of the two-step stope by a certain height to improve the stress distribution of the roof, transfer and reduce high ground stress, and "decompress" the stope roof and side walls. This mining method solves the problem of safe and efficient mining of ore bodies under deep well high ground stress and "three-down" conditions, which cannot be mined by medium-deep hole large-scale blasting.

Description

Technical Field

[0001] The invention relates to a mining method suitable for "deep well" or "three-under" underground metal ore bodies, belonging to the technical field of mining. Background Art

[0002] "Deep well" mines have large ground stress, and "three-down" ore body mining is carried out to control surface deformation, and the exposed space of the mining site is limited, resulting in the inability to use medium-thick to thick ore bodies for deep hole mining. The currently commonly used upward approach layered filling method has poor roof safety and high mining safety risks due to large ground stress and the inability to fill and connect the approach. Summary of the Invention

[0003] To address the problems of poor roof safety and high mining safety risks during the mining of deep-well, high-in-situ stress or "three-down" underground metal ore bodies, the present invention proposes a mining method suitable for "deep-well" or "three-down" underground metal ore bodies. The method involves dividing the ore block into two-step stopes for upward layered mining, with the stope length direction perpendicular to the horizontal principal stress, and the first-step stope leading the second-step stope by 3 to 4 layers. The advanced mining and filling stopes isolate the other stopes from the high horizontal stress, achieving a "stress relief" effect. Each stope within the ore body is fully mined upward layer by layer at different layer heights, transferring vertical stress to the surrounding rock around the ore body. The stope roof ore rock is placed in a "stress relief zone," reducing the stress on the stope roof and side walls, which is beneficial to the safety of the stope roof and side walls. The use of upward layered mining not only controls the exposed area of ​​the stope roof, but also uses shallow-hole, micro-difference blasting to reduce the destructive effects of blasting vibration on surface structures. This mining method can solve the problem of safe and efficient mining of ore bodies in deep wells with high ground stress and "three down" conditions where medium-deep hole large-scale blasting cannot be used.

[0004] At present, mines with ore bodies buried at a depth of more than 600 to 800 meters are generally called "deep well" mines. "Deep well" mines are characterized by high ground stress. "Three-under" ore bodies refer to ore bodies located under surface water bodies, buildings and railways (highways). The mining of such ore bodies requires that the riverbed deformation be controlled within the allowable range to prevent surface water from flowing into the well and causing floods, and the deformation of ground buildings and railway (highway) trunk lines be controlled within the allowable range.

[0005] A mining method suitable for "deep well" or "three-down" underground metal ore bodies, the specific steps are as follows:

[0006] (1) Stope division: The underground metal ore body with high ground stress or "three-down" in deep wells is divided into stages, and the stages are divided into segments along the vertical height. The segments are divided into ore blocks along the strike of the ore body, and the blocks are divided into stopes. Two-step stopes are arranged according to the horizontal principal stress direction, vertical direction or along the strike of the ore body. The length direction of the stope is perpendicular to the principal stress direction. The two-step stopes in the ore block are staggered and the stopes are mined in layers. The first-step stope is 3 to 4 layers ahead of the second-step stope. The stope with advanced mining and filling blocks the horizontal high stress for other stopes, achieving the purpose of "pressure relief";

[0007] (2) Layout of mining and cutting engineering: In the middle section, a sub-section mining tunnel is arranged along the strike of the ore body in the footwall of the ore body. A mining route with a slope of 10-12% is arranged every 50-100m along the length of the sub-section mining tunnel to the ore body rock boundary of the footwall of the ore body. The mining routes are arranged in a staggered manner to serve as the mining routes of the first-step stope and the second-step stope. When the stopes are arranged along the inclination, a first-step stope layered joint is arranged in the ore vein at the boundary of the ore body footwall to the ore block boundary. In the first-step stope, 3-4 layers are mined in advance, and a filling body is filled 3-6m away from the first-step layered joint in the footwall of the ore body, and then a second-step stope layered mining joint is arranged. Filling return air shafts are arranged at both ends of the layered mining joint to the end of the mining route joint of the upper section to form a return air filling system.

[0008] When the stope is arranged along the strike, the stratified mining roadway is arranged along the inclination of the ore body;

[0009] (3) Mining and filling: adopt two-step stope stratified mining, firstly mine the first layer and the first step stope, and the first step stope adopts cement filling; after the stratified mining of the first step stope in the ore block is completed, the stratified mining joint of the first layer and the first step stope is cemented and filled; after the first layer filling body of the first step stope reaches the curing age, the second layer mining and filling operation is carried out, and the upward stratified mining is carried out in turn; after 3 to 4 layers are mined in the first step stope, the second layer of the second step stope is constructed. The first-layer mining joint track is a construction equipment tunnel in the first-layer mining joint track that passes through the backfill in the first-step stope mining joint track and then mines the second-step stope. The bottom layer of the second-step stope is non-cemented, and the surface layer is cemented. Each stope in the ore body is mined upward layer by layer at different layer heights to transfer vertical stress to the surrounding rock of the ore body. The stope roof ore rock is in the pressure relief zone to improve the safety of the stope roof and side walls. The layer mining joint track is filled together with the last stope mined in that layer.

[0010] Except for the first layer, before mining each layer in each section, the mining access road is topped, the waste rock is compacted at the bottom, and layered mining joints are constructed; when filling each layer, a blank area of ​​a preset height is left as blasting compensation space for mining the next layer upward.

[0011] Preferably, the length of the ore block in step (1) is 80 to 100 m along the strike of the ore body, and the width is the horizontal thickness of the ore body;

[0012] Preferably, the width of the stope in step (1) one is 5 to 8 m, the width of the stope in step two is 7 to 10 m, and the stope layered top control height is 4.0 to 5.5 m.

[0013] Preferably, the height of the segmented mining tunnel in step (2) is 10 to 15 m.

[0014] Preferably, in the step (2), when the stope is arranged along the inclination of the ore body, the stratified mining links are arranged along the strike of the ore body, and the stratified mining links of the first-step stope are arranged in the ore vein, and the stratified mining links of the second-step stope are arranged on the side of the first-step stratified mining links away from the ore body; when the stope is arranged along the strike, the stratified mining links are constructed at the end of the segmented mining approach to the upper wall of the ore body, and except for the first layer, the stratified mining links of each layer of each section are arranged on the filling body of the previous stratified mining link.

[0015] Preferably, in step (3), the compressive strength of the bottom filling body 28d of the mining area in the first step is not less than 1.0MPa, the compressive strength of the surface filling body 7d is 1.2-1.5Mpa, and the thickness of the surface filling body is 0.5-0.6m; the compressive strength of the surface filling body 7d of the mining area in the second step is 1.2-1.5Mpa, and the thickness of the surface filling body is 0.5-0.6m.

[0016] Preferably, in step (3), the top height of the mining layer is controlled at 4.0 to 5.5 m, and the preset height of the blank area is 1.0 to 1.5 m.

[0017] Preferably, in step (3), the first-step stope and the second-step stope are arranged alternately, the cemented filling body of the first-step stope is the side wall of the second-step stope, and the filling body strength satisfies the requirement that no spalling or collapse occurs during the second-step mining.

[0018] Preferably, in step (3), a digital detonator micro-difference shallow hole blasting method is adopted to control the impact of blasting vibration on surface structures and rivers.

[0019] Preferably, in step (3), support methods such as anchor rods or anchor rod-anchor nets can be adopted according to the conditions of the roof rock mass.

[0020] The beneficial effects of the present invention are:

[0021] (1) The mining method of the present invention adopts a small-section two-step continuous layered mining method, and the two-step mining methods are staggered by 3 to 4 layer heights, which plays a role in stress isolation and pressure relief. It is suitable for the mining of medium-thick to thick ore bodies in a "deep well" high stress environment;

[0022] (2) The two-step stopes of the mining method of the present invention are staggered in the vertical direction, the exposed area of ​​the stope roof is small, and the tensile stress in the ore rock of the stope roof is less than the tensile strength of the ore rock. This solves the problem of the large overall exposed area of ​​the roof of multiple routes, poor roof stability, and high safety risks caused by the inability to connect the filling when the same layer is mined and filled in two-step routes of the approach-type upward layered filling method;

[0023] (3) The mining method of the present invention adopts a two-step recovery process without leaving permanent pillars, thereby improving the ore recovery rate;

[0024] (4) The mining method of the present invention arranges multiple ore blocks and multiple stopes in the horizontal direction of the ore body for simultaneous mining, and adopts high-efficiency trackless self-propelled equipment to improve mining efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic cross-sectional view of a stope in one step;

[0026] Figure 2 This is a schematic cross-section diagram of the two-step stope;

[0027] Figure 3 This is a schematic diagram of a step-by-step layering plan;

[0028] Figure 4 This is a schematic diagram of the two-step layering plan;

[0029] Figure 5 Schematic diagram of the longitudinal section of the one-step stope and the two-step stope. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0031] The present invention employs continuous mining in one- and two-step stopes, suitable for mining ore bodies under "deep well" high stress or "three-down" conditions. The ore body is first divided into stages, which are then divided into segments along their vertical height. Within each stage and segment, the ore body is divided into blocks along its strike. Within each block, one-step and two-step stopes are then divided. Mining and backfilling are then performed in layers within each segment. Stopes are arranged so that their lengths are perpendicular to the principal direction of in-situ stress. Adjacent step stopes are staggered, with the one-step stope preceding the two-step stope by a certain height. This improves roof stress distribution, reduces high in-situ stress, and relieves pressure on the stope roof and side walls. This mining method addresses the problem of safe and efficient mining of ore bodies under deep well high in-situ stress or "three-down" conditions, where medium- to long-hole blasting is unsuitable.

[0032] Summary of the Invention

[0033] like Figures 1 to 5As shown, a mining method suitable for "deep well" or "three-down" underground metal ore bodies, the specific steps are as follows:

[0034] (1) Stope division: Divide the underground metal ore body with high ground stress or "three-down" in the deep well into stages, divide the stages into sections along the vertical height, and divide the sections into blocks along the strike of the ore body. The length of the block is 80-100m along the strike of the ore body, and the width is the horizontal thickness of the ore body; divide the stope within the block, and arrange two-step stopes according to the horizontal principal stress direction, vertical direction or along the strike of the ore body. The stope length direction is perpendicular to the principal stress direction. The two-step stopes within the block are staggered, with the width of the first step stope being 5-8m and the second step stope being 7-10m. The stope layer control top height is 4.0-5.5m; the stope is mined in layers, with the first step stope leading the second step stope by 3-4 layers; the stope with advanced mining and filling blocks the horizontal high stress for other stopes, achieving the purpose of "pressure relief";

[0035] (2) Mining and cutting engineering layout: In the middle section, a sub-section mining tunnel is arranged along the strike of the ore body in the footwall of the ore body. The height of the sub-section mining tunnel is 10-15m. A mining access road with a slope of 10-12% is arranged every 50-100m along the length of the sub-section mining tunnel to the ore rock boundary of the ore body footwall. The mining access roads are staggered to serve as the mining access roads of the first-step stope and the second-step stope. When the stopes are arranged along the inclination, a first-step stope layered joint road is arranged in the ore vein at the boundary of the ore body footwall to the ore block boundary. In the first-step stope, 3-4 layers are mined in advance, and a filling body is filled 3-6m away from the first-step layered joint road in the footwall of the ore body, and then a layered mining joint road of the second-step stope is arranged. Filling return air shafts are arranged at both ends of the layered mining joint road to the end of the mining access road of the upper section to form a return air filling system.

[0036] When the stope is arranged along the strike, the stratified mining roadway is arranged along the inclination of the ore body;

[0037] Specifically, the stratified mining joint track is arranged along the strike of the ore body when the stope is arranged along the inclination of the ore body, and the stratified mining joint track of the first-step stope is arranged in the ore vein, and the stratified mining joint track of the second-step stope is arranged on the side of the first-step stratified mining joint track away from the ore body; when the stope is arranged along the strike, the stratified mining joint track is constructed from the end of the staged mining approach to the hanging wall of the ore body, and except for the first layer, the stratified mining joint track of each layer of each section is arranged on the filling body of the previous stratified mining joint track;

[0038] (3) Mining and filling: adopt two-step stope stratified mining, firstly mine the first layer and the first step stope, and cement filling is adopted for the first step stope; after the stratified mining of the first step stope in the ore block is completed, the stratified mining joint of the first layer and the first step stope is cemented and filled, the 28d compressive strength of the bottom filling body of the first step stope is not less than 1.0MPa, the 7d compressive strength of the surface filling body is 1.2~1.5Mpa, and the thickness of the surface filling body is 0.5~0.6m; after the first layer filling body of the first step stope reaches the 7d curing age, the second layer mining and filling operation is carried out, and the upward layer mining is carried out in turn; after 3~4 layers are mined in the first step stope, the cement filling is applied. The first layer mining joint track of the second-step stope is mined from the construction equipment tunnel in the first layer mining joint track through the filling body in the first-step stope mining joint track, and then the second-step stope is mined. The bottom layer of the second-step stope is filled with non-cemented filling such as waste rock and tailings, and the surface layer is filled with cemented filling. The 7-day compressive strength of the surface filling body of the second-step stope is 1.2-1.5 MPa, and the thickness of the surface filling body is 0.5-0.6 m. Each stope in the ore body is fully mined upward layer by layer at different layer heights to transfer vertical stress to the surrounding rock of the ore body. The stope roof ore rock is in the pressure relief zone to improve the safety of the stope roof and side walls. The layered mining joint track is filled together with the stope of the last mined layer.

[0039] Except for the first layer, before mining each layer in each section, the mining approach is topped, the waste rock is compacted at the bottom, and a layered mining joint is constructed; the top height of the mining layer in the stope is controlled at 4.0 to 5.5 meters, and a blank area of ​​a preset height of 1.0 to 1.5 meters is left when filling each layer as blasting compensation space for mining the next layer upward;

[0040] The first-step stope and the second-step stope are arranged alternately. The cemented filling of the first-step stope serves as the side wall of the second-step stope. The filling strength satisfies the requirement that no wall collapse will occur during the second-step mining. Digital detonators are used for micro-difference shallow hole blasting to control the impact of blasting vibration on surface structures. Support methods such as anchor rods or anchor rod-anchor nets can be adopted according to the conditions of the roof rock.

[0041] Example 1: In a metal mine, the ore body is about 850m deep, with a nearly east-west strike of 1000m, a north-south length of 40m, and an average vertical thickness of 30m. The maximum principal stress in the ore body is mainly manifested as horizontal stress in the east-west direction. The specific implementation steps are as follows:

[0042] (1) Division of the pan area stope; the ore body is divided into ore blocks every 80m along the strike of the ore body, and the ore body is divided into layers in the ore blocks according to the one-step and two-step stopes. The stope is arranged perpendicular to the strike of the ore body, the width of the one-step stope is 5m, the width of the two-step stope is 7m, and the top height of the layers is 5m. The one- and two-step stopes are staggered in the horizontal direction, and the one-step stope is evenly arranged in layers of 5m in the vertical direction. The two-step stope has a top height of 3m in the first mining layer, and except for the top layer, the top height of the other upper layers is 5m, evenly arranged, and the top layer can be mined in sections; so that a certain height difference is formed between the one-step and two-step stopes in the vertical direction, the one-step stope;

[0043] (2) Arrangement of mining project: Since there is a certain height difference between the first and second step mining sites in the vertical direction, an independent layered mining link is arranged for each layer of each step mining site; the layered mining link of the first step is at the same height as the first step mining site and is arranged in the vein of the footwall of the ore block; the layered mining link of the second step is arranged 2m outside the layered mining link of the first step according to the height difference; at the same time, segmented vein lanes are arranged outside the vein of the ore body bottom plate, and segmented mining lanes are arranged from the vein lanes outside the vein to the layered mining links of each step mining site of the ore block; among them, the segmented mining lanes of the first step are connected with the layered mining links on both sides of the ore block in the east and west directions at a downward slope of 10%, and the mining links of the second step mining site are connected with the layered mining links at the center of the ore block at a downward slope of 11%; secondly, in the upper segmented layered mining link, ventilation and filling wells are arranged along the inclination direction of the ore body to the lower segmented layered mining link;

[0044] (3) Mining and filling; when each ore block is mined, firstly, a first-step stope of a layer is mined, and a low-cement filling of 4.5m is used in the lower part of the stope, followed by a high-cement surface filling of 0.5m thickness. After the mining of the last first-step stope of a layer is completed, the stope and the first-layer layer mining link are filled in the above-mentioned manner; after the filling is completed, the top of the segmented mining tunnel outside the vein is brushed and raised, and the collapsed rock debris is compacted and paved to form a second-layer segmented mining tunnel of the first-step stope and mining is carried out; according to the above-mentioned steps, the first-step stope is mined until the top layer of the segment, and then the second-step stope is mined;

[0045] From the segmented mining tunnel excavated along the vein to the segmented mining tunnel of the first layer of the second-step stope, when mining the first layer of the second-step stope, mining can be carried out from the corresponding position of the segmented mining tunnel to the second-step stope; at this time, the second-step stope will pass through the segmented mining tunnel of the cemented filling of the first-step stope, and the filling body can be separated; after the mining of the first-layer second-step stope is completed, the bottom of the stope will be filled with 2.5m thick non-cemented tailings, and the upper part will be filled with a 0.5m thick high-cemented surface layer. After the mining and filling of the last second-step stope of the first layer is completed, the stope and the segmented mining tunnel of the first layer will be filled according to the filling method of the second-step stope. Subsequently, the top of the segmented mining tunnel outside the vein is also brushed and raised to form the mining conditions of the upper layer of the second-step stope;

[0046] The low-cement filling at the bottom of the first-step stope must have a 28-day strength of no less than 1MPa, and the high-cement filling at the surface must have a 7-day strength of 1.2-1.5MPa, to meet the requirements for trackless equipment operation during upper-layer mining. During the mining process, fresh air flows from the upper-layer filling return air shaft into the current layer mining joint, while polluted air flows through the sub-layer mining laneway into the vein laneway outside the vein and into the mine return air system.

[0047] (4) The ore body of this mine is buried at a depth of about 850m, and its maximum principal stress is mainly manifested as horizontal principal stress. At this time, the ore body is divided into ore blocks along the strike. As the stopes in the ore blocks are mined, the transmission of horizontal principal stress is blocked. At the same time, since goafs are formed when the stopes are mined, the compressive stress on the upper part of the stope roof is transferred to the surrounding area of ​​the stope, and the stope mining span is small, the tensile stress value generated on the roof does not exceed the tensile strength of the roof, ensuring the stability of the stope mining. Each stope in the ore body is mined upward layer by layer at different layer heights, transferring the vertical stress to the surrounding rock around the ore body. The stope roof ore rock is in the pressure relief zone to improve the safety of the stope roof and side walls, ensuring the safe mining of the road-type stope.

[0048] The approach strip is used to reduce the exposed area of ​​the mining site to adapt to the "deep well" mining under complex ground stress conditions.

[0049] Example 2: In a metal mine, the ore body is buried 300m below the surface, strikes NE40° to SW220°, has a strike angle of 750m, an oblique length of 20m, and an average vertical thickness of 24m. There is a national highway above the mining area, and surface subsidence is not allowed in the mining area. The specific implementation steps are as follows:

[0050] (1) Block stope division: The ore body is divided into blocks every 90m along the strike of the ore body, and the ore body within the block is divided into layers in sequence according to the one- and two-step stopes; the stopes are arranged perpendicular to the strike of the ore body, with a one-step stope width of 6m and a two-step stope width of 8m, and a layered top control height of 4m. The one- and two-step stopes are arranged alternately in the horizontal direction, and the one-step stope is evenly arranged in 4 layers in the vertical direction. The two-step stope is evenly arranged in the vertical direction, with the first mining layer top control height of 3m and the remaining upper layers top control height of 4m, and they are evenly arranged, forming a certain height difference between the one- and two-step stopes in the vertical direction;

[0051] (2) Layout of mining project: Since there is a certain height difference between the first and second step mining sites in the vertical direction, an independent layered mining link is arranged in each layer of each step mining site; the layered mining link of the first step is at the same height as the first step mining site and is arranged in the vein of the lower plate of the ore body; the layered mining link of the second step is arranged 2m outside the layered mining link of the first step according to the height difference. At the same time, segmented along-vein lanes are arranged outside the vein of the ore body bottom plate, and segmented mining link is arranged from the segmented along-vein lane outside the vein to the layered mining link of each step mining site of the ore block. The segmented mining link of the first step mining site is arranged on both sides of the east and west directions of the ore block (east-west direction) at a downward slope of 10% and is connected to the layered mining link. The segmented mining link of the second step mining site is arranged in the center of the ore block and is connected to the layered mining link at a slope of 11%; secondly, a filling return air shaft is arranged in the upper segmented layered mining link to the lower segmented layered mining link;

[0052] (3) Mining and filling; when each ore block is mined, first mine the first-step stope of one layer, and then mine and fill them one by one. After the mining of the first-step stope is completed, the lower part of the stope is filled with low-cement filling of 3.5m, and then a high-cement surface layer with a thickness of 0.5m is filled; after the mining of the last stope of a layer is completed, the stope and the first-layer mining connection are filled according to the filling method of the first-step stope; after the filling is completed, the top of the vein-outside segmented mining tunnel is brushed and raised, and the collapsed rock debris is compacted and paved to form the segmented mining tunnel of the upper layer and the second-layer mining is carried out; according to the above steps, the first-step stope is mined until the top layer of the segment, and then the second-step stope is mined;

[0053] From the segmented vein tunnel, the segmented mining tunnel is excavated to the first layer of the second-step stope. When the first layer is mined and the second-step stope is mined, the second-step stope can be mined from the corresponding position of the segmented mining tunnel. At this time, the second-step stope will pass through the segmented mining tunnel of the cemented filling of the first-step stope, and the filling body can be separated. After the mining of the first-layer second-step stope is completed, the bottom of the stope will be filled with 2.5m thick non-cemented tailings, and the upper part will be filled with 0.5m thick high-cemented surface layer. After the last second-step stope of the first layer is mined, the stope and the segmented mining tunnel will be filled in the same way as the second-step stope. Subsequently, the top of the mining tunnel outside the vein is also raised to form the mining conditions of the upper layer of the second-step stope.

[0054] The low-cement filling at the bottom of the first-step stope must have a 28-day strength of no less than 1MPa, and the high-cement filling at the surface must have a 7-day strength of 1.2-1.5MPa to meet the requirements for trackless equipment operation during upper-layer mining. During the mining process, fresh air flows from the upper-layer filling return air shaft into the current layer mining joint, and polluted air flows through the sub-layer mining laneway into the vein laneway outside the vein and then into the mine return air system.

[0055] (4) When the ore body is buried at a shallow depth of 300m, in order to ensure that the surface structures are not affected or are less affected by the mining of the ore body, an approach strip is adopted. The exposed area and span of the stope are small, and the tensile stress value generated in the stope roof is low, which ensures the stability of the stope roof. In addition, the staggered arrangement of the first and second step stopes in the vertical direction and the multiple layered mining of the second step stope lagging behind the first step stope further improve the safety of the stope roof and side walls, so that the deformation of the surface structure is controlled within the allowable deformation range, so as to adapt to the mining conditions under the "three down" conditions and reduce the impact on the surface structures.

[0056] Example 3: A mining method applicable to "deep well" or "three-down" underground metal ore bodies, the specific steps are as follows:

[0057] At a metal mine, the orebody runs north-south, is 500 meters long, 25 meters diagonally east-west, and has an average vertical thickness of 40-50 meters. The remaining mining areas are mined using a staged open-stop and subsequent backfill method. The northern mining area, with its upper surface covered by farmland and buried 200 meters below the surface, has an orebody thickness of approximately 30 meters. Mining is carried out using an upward, layered approach with strips.

[0058] (1) Block stope division: The ore body is divided into blocks every 73m along the strike of the ore body, and the ore body within the block is divided into layers in sequence according to the one- and two-step stopes. The stopes are arranged perpendicular to the strike of the ore body, with a one-step stope width of 5m and a two-step stope width of 7m, and a layered top control height of 5m; the one- and two-step stopes are arranged alternately in the horizontal direction, and the one-step stope is evenly arranged in 6 layers in the vertical direction; in the two-step stope, the first mining layer has a top control height of 4m, and the other upper layers have a top control height of 5m, and the last layer is up to the top of the segment. This creates a certain height difference between the one- and two-step stopes in the vertical direction;

[0059] (2) Mining project layout: Since there is a certain height difference between the first and second step stopes in the vertical direction, considering the subsequent mining of the upper layer, a layered mining joint road is arranged for each layer of the first and second step stopes, and the two step stopes are mined independently. The layered mining joint road of the first step stope is arranged along the ore body inside the bottom plate vein, and the layered mining joint road of the second step stope is arranged 2m outside the first step stope along the vein; the segmented vein road is arranged outside the bottom plate vein of the ore body, and the segmented vein road is arranged according to the direction of the ore body. +Arrange the mining joints to the stratified mining joints at a slope of 10%. The stratified mining joints for the first-step stope are arranged on the north and south sides of the ore block, and the stratified mining joints for the second-step stope are arranged in the center of the ore block. Filling return air shafts are arranged in the stratified mining joints of the upper unmined sections to the strata of the current mining section.

[0060] (3) Mining and filling: adopt upward stratified mining, and firstly mine the first-step stope. After mining, the lower part of the stope is filled with 4.5m of low-cement filling, and the strength reaches 1MPa after 28 days, followed by 0.5m of high-cement filling, and the strength reaches 1.3MPa after 7 days. When the last stope of the layer is mined, the stope and the stratified mining joint are filled in the same way as the first-step stope. After the mining of the current layer is completed, the mining joint is raised by brushing the top to compact the collapsed ore and rock, forming the mining joint of the stratified mining on the first-step stope. When the first-step stope has mined the fourth layer and is mining the fifth layer, the second-step stope of the segmented one layer can be mined at the same time.

[0061] When the second-step stope is mined, the mining joint track is connected with the layered mining joint track, and the second-step stope is mined in strips. At this time, the second-step stope will pass through the layered mining joint track of the first-step stope where the cemented filling is completed, and the filling body can be separated; when the mining of a second-step stope of a layer is completed, the lower part of the stope is filled with non-cemented filling of 3.5m, followed by a 0.5m thick high-cemented surface layer filling, and the 7d strength reaches 1.3MPa; after the mining of the first layer is completed, the last mined second-step stope and the layered mining joint track are filled together according to the filling method of the second-step stope; and the mining joint track is brushed and raised, and the collapsed rock debris is compacted to form the layered mining joint track on the second-step stope; thereafter, the second-step stope is mined and filled at a layer height of 5m;

[0062] During the mining process, fresh air flows through the upper sub-level and layered mining joints and enters the layered mining joints of the current mining seal layer from the filling return air shaft. The polluted air generated during the generation process flows through the current mining layer from the mining joints into the current mining sub-level vein tunnels and enters the mine return air system.

[0063] (4) By adopting the approach-type strip mining method, compared with the staged emptying and subsequent filling method with large structural parameters, the span and exposed area of ​​the mining area are small, the displacement of the roof is small, and the mining area structure is more stable; secondly, the height difference formed in the vertical direction of the one- and two-step approach-type strip mining area, after the mining area is excavated, the vertical stress in the upper part of the mining area is transferred to the surrounding area, and a pressure relief zone is generated in the upper part of the mining area, which improves the safety of the mining area roof and side walls; at the same time, it can also reduce the displacement of the upper rock mass, so that the surface subsidence is controlled within the allowable range, ensuring the stability of the surface farm buildings.

[0064] The above describes the specific embodiments of the present invention in detail, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the scope of the present invention.

Claims

1. A mining method suitable for "deep well" or "three-under" underground metal ore bodies, characterized in that: The specific steps are as follows: (1) Stope division: Divide the underground metal ore body with high ground stress or "three-down" deep well into stages, divide the stages into segments along the vertical height, divide the segments into ore blocks along the strike of the ore body, and divide the blocks into stopes. Arrange two-step stopes according to the horizontal principal stress direction, vertical direction or along the strike of the ore body. The length direction of the stope is perpendicular to the principal stress direction. The two-step stopes are staggered in the ore block. The stopes are mined in layers, and the first-step stope is 3 to 4 layers ahead of the second-step stope. (2) Layout of mining and cutting engineering: In the middle section, a sub-section mining tunnel is arranged along the strike of the ore body in the footwall of the ore body. A mining route with a slope of 10-12% is arranged every 50-100m along the length of the sub-section mining tunnel to the ore body rock boundary of the footwall of the ore body. The mining routes are arranged in a staggered manner to serve as the mining routes of the first-step stope and the second-step stope. When the stopes are arranged along the inclination, a first-step stope layered joint is arranged in the ore vein at the boundary of the ore body footwall to the ore block boundary. In the first-step stope, 3-4 layers are mined in advance, and a filling body is filled 3-6m away from the first-step layered joint in the footwall of the ore body, and then a second-step stope layered mining joint is arranged. Filling return air shafts are arranged at both ends of the layered mining joint to the end of the mining route joint of the upper section to form a return air filling system. When the stope is arranged along the strike, the stratified mining roadway is arranged along the inclination of the ore body; (3) Mining and filling: adopt two-step stope stratified mining, first mine the first layer one-step stope, and use cemented filling for the one-step stope; after the stratified mining of the one-step stope in the ore block is completed, the stratified mining link of the one-step stope is cemented and filled; after the first layer filling body of the one-step stope reaches the curing age, the second layer mining and filling operation is carried out, and the stratified mining is carried out in a circular upward cycle; after 3 to 4 layers are mined in the one-step stope, the first layer mining link of the two-step stope is constructed, and the second-step stope is mined after the construction roadway in the first layer mining link passes through the filling body in the first step mining link. The bottom layer of the second step stope is non-cemented and the surface layer is cemented; each stope in the ore body is fully mined upward layer by layer at different layer heights to transfer the vertical stress to the surrounding rock around the ore body, and the mine roof ore rock is in the pressure relief zone; the stratified mining link is filled together with the stope of the last mined layer; Except for the first layer, before mining each layer in each section, the mining access road is topped, the waste rock is compacted at the bottom, and layered mining joints are constructed; when filling each layer, a blank area of ​​a preset height is left as blasting compensation space for mining the next layer upward.

2. The mining method for a "deep well" or "three-under" underground metal ore body according to claim 1, characterized in that: In step (1), the width of the first-step stope is 5 to 8 m, the width of the second-step stope is 7 to 10 m, and the top control height of the stope layer is 4.0 to 5.5 m.

3. The mining method for a "deep well" or "three-under" underground metal ore body according to claim 1, characterized in that: The segment height of step (2) is 10 to 15 m.

4. The mining method for a "deep well" or "three-under" underground metal ore body according to claim 1, characterized in that: The stratified mining links described in step (2) are arranged, when the stope is arranged along the inclination of the ore body, the stratified mining links are arranged along the strike of the ore body, and the stratified mining links of the first-step stope are arranged in the ore vein, and the stratified mining links of the second-step stope are arranged on the side of the first-step stratified mining links away from the ore body; when the stope is arranged along the strike, the stratified mining links are constructed at the end of the segmented mining approach to the upper wall of the ore body, and except for the first layer, the stratified mining links of each layer of each segment are arranged on the filling body of the previous stratified mining link.

5. The mining method for a "deep well" or "three-under" underground metal ore body according to claim 1, characterized in that: In step (3), the compressive strength of the bottom filling body of the mining area at 28d is not less than 1.0MPa, the compressive strength of the surface filling body at 7d is 1.2-1.5Mpa, and the thickness of the surface filling body is 0.5-0.6m; in step (3), the compressive strength of the surface filling body of the mining area at 7d is 1.2-1.5Mpa, and the thickness of the surface filling body is 0.5-0.6m.

6. The mining method for a "deep well" or "three-under" underground metal ore body according to claim 1, characterized in that: In step (3), the top height of the mining layer is controlled at 4.0 to 5.5 m, and the preset height of the blank area is 1.0 to 1.5 m.

7. The mining method for a "deep well" or "three-under" underground metal ore body according to claim 1, characterized in that: In step (3), the first-step stope and the second-step stope are arranged alternately, and the cemented filling body of the first-step stope serves as the side wall of the second-step stope.

Images