A safe and efficient combined mining method for caving and backfilling without the need for isolation pillars.

Abstract

This invention provides a safe and efficient combined mining method of caving and backfilling without the need for isolation pillars. It is used for subsequent mining when the ore body has been mined using the caving method to the point where the collapse area is close to the location of surface buildings. The method includes: Step 1, dividing the ore body to be mined into multiple mining stages vertically; Step 2, determining the mining method: for the ore body located on the side of the surface boundary where surface buildings are located, backfilling mining is proposed, while for the ore body on the other side, caving mining is proposed; the two mining methods are at the same stage height, and the overall mining sequence is from top to bottom; Step 3, determining the vertical boundary between the two mining methods through formula calculation; Step 4, simultaneous mining of backfilling and caving methods: for the backfilling mining area, mining is carried out from the side of the vertical boundary line towards the outside of the boundary line; for the caving mining area, mining is carried out from the outside of the boundary line towards the vertical boundary line.

Description

Technical Field

[0001] This invention belongs to the field of underground mining methods, specifically relating to a safe and efficient combined mining method of caving and backfilling without the need for isolation pillars. Background Technology

[0002] Because mineralization is complex, the occurrence of ore bodies can vary. In particular, the occurrence of ore bodies in some mines is quite complex, with ore bodies exhibiting branching, overlapping, large variations in occurrence, and well-developed fault structures, joints, and fractures. Using a single mining method cannot meet production needs, which requires mines to select two or more mining methods in combination to achieve the best results.

[0003] Bottomless caving significantly simplifies mining methods, creating favorable conditions for the use of trackless self-propelled equipment and ensuring worker safety. However, its most basic requirement is permissible surface subsidence. As mining deepens and the subsidence zone expands into the building area, bottomless caving becomes less suitable. The most effective solution to surface subsidence is backfilling the goaf, allowing for simultaneous backfilling and caving operations. Backfilling mining offers advantages such as reduced ore dilution, improved ventilation, prevention of mine fires, and control of rock bursts and surface collapse. However, it also has lower production efficiency and higher costs, making it difficult to meet current mine demands given low ore prices.

[0004] As mining progresses deeper, the surface subsidence area extends into the construction zone, creating a conflict between the safety of the concentrator production and efficient underground mining. While conventional combined backfilling and caving mining methods have solved the problem of reserving a large number of safety pillars to some extent by setting up isolation pillars, they have also led to difficulties in recovering residual ore from the isolation pillars and complex geological conditions for residual ore recovery. Summary of the Invention

[0005] This invention was developed to address the aforementioned problems and aims to provide a safe and efficient combined mining method for caving and filling without the need for isolation pillars. This method enables efficient mining of deep ore bodies without the need for isolation pillars, effectively reduces residual ore volume, and improves mine recovery rate.

[0006] To achieve the above objectives, the present invention employs the following solution:

[0007] This invention provides a safe and efficient combined mining method for caving and backfilling without the need for isolation pillars. It is used for subsequent mining when the ore body has been mined by caving to the point where the collapse area is close to the location of surface buildings. The method is characterized by the following steps:

[0008] Step 1: Divide the ore body into multiple mining stages vertically. Arrange transport roadways in each segment within the stage. The stope is connected to the transport roadways of each segment through connecting roadways.

[0009] Step 2: Preliminary Determination of Mining Method:

[0010] The edge of the area where the surface buildings are located is taken as the surface base boundary. For the ore body on the side where the surface buildings are located, which is located on the surface base boundary, the filling method is to be used for mining. For the ore body on the other side away from the surface buildings, the caving method is to be used for mining. The two mining methods are highly consistent in stage and adopt a top-down mining sequence as a whole.

[0011] Step 3: Determine the vertical boundary between the two mining methods:

[0012] The values ​​of the translation angle parameters X and Y are calculated using the following formulas:

[0013]

[0014]

[0015] In the formula, α is the dip angle of the ore body, β0 is the initial failure surface movement angle, H0 is the depth of the overlying granular material, H1 is the depth at the end of mining, γ is the unit weight of the hanging wall, c' is the cohesion, and γ c The bulk density of the disintegrating material. K is the internal friction angle between the granular material and the rock mass. p1 K is the coefficient of lateral pressure acting on the initial slip surface. p2 The coefficient of lateral pressure acting on the hanging wall surrounding rock;

[0016] Then, based on the movement angle parameters X and Y, the upper wall movement angle β is obtained. Further, based on the mining depth H1 and the surface foundation boundary, the upper boundary line of the ore body is determined, which is located at the top of the underground ore body to be mined and whose connection surface with the surface foundation boundary extends from top to bottom towards the side away from the surface buildings, with an included angle of β.

[0017] Next, on a section perpendicular to the ore entry route: starting from point C0 where the boundary line on the ore body is located, a vertical boundary line C0C1 is formed by extending downwards and towards the side away from the surface buildings in a stepped manner until the bottom C1 of the final mining stage. The angle of inclination of this vertical boundary line is greater than the rock movement angle. The mining areas for the two mining methods are divided with the vertical boundary line as the final boundary. The ore body on the side where the surface buildings are located on the vertical boundary line is the filling method mining area, and the ore body on the side away from the surface buildings is the caving method mining area. The stepped vertical boundary line coincides with the edge contour of the blast holes at each stage at the boundary of the caving method mining area. The stepped contour is presented according to the upward fan-shaped hole contour.

[0018] Step 4: Simultaneous mining using both backfilling and caving methods:

[0019] For backfill mining areas: Backfill mining areas shall be mined in the order of moving from the vertical boundary line to the outer side away from the vertical boundary line;

[0020] For caving mining areas: the bottom pillarless caving method is adopted, and the mining sequence in the caving mining area is from the outside away from the vertical boundary line to the side of the vertical boundary line.

[0021] Preferably, the safe and efficient combined mining method of caving and backfilling without setting isolation pillars provided by the present invention may also have the following features: in step 4, the side of the vertical dividing line is defined as the inner side and the side away from the vertical dividing line is defined as the outer side; for the caving mining area, each mining sub-stage is set sequentially from the outer side to the inner side along the horizontal direction within each stage; for the backfilling mining area, each mining sub-stage is set sequentially from the inner side to the outer side along the horizontal direction, with one mining sub-stage every other.

[0022] Preferably, the safe and efficient combined mining method of caving and backfilling without setting isolation pillars provided by the present invention may also have the following feature: in step 4, for the backfilling mining area, the ridge residue of the odd-numbered stages near the vertical dividing line is mined back by drilling fan-shaped holes in the even-numbered stage stopes.

[0023] Preferably, the safe and efficient combined mining method for caving and backfilling without setting isolation pillars provided by the present invention may further include: in step 4, multiple mining stages and sub-stages can be mined simultaneously; in step 1, the method for dividing each stage is as follows: based on the classification of the rock mass to be mined, the maximum allowable exposed volume of the stope for different mining methods is evaluated, and the segment height is determined based on the allowable goaf exposure height of the medium-deep hole stope.

[0024] Preferably, the safe and efficient combined mining method of caving and backfilling without setting isolation pillars provided by the present invention may also have the following features: in step 4, for the ore body near the boundary line area mined by caving method, pre-splitting blasting is used; for the ore body near the vertical boundary line area mined by backfilling method, smooth blasting is used, and the blasting height of the backfilling method is less than or equal to 3m.

[0025] Preferably, the safe and efficient combined mining method of caving and backfilling without setting isolation pillars provided by the present invention may also have the following features: In step 4, for the area mined by the backfilling method, the ore body to be mined is divided into stopes and pillars in the horizontal direction along the ore body strike. The backfilling mining method combined with the medium-deep hole segmented backfilling mining method is used for mining. Each stope in the stope and pillar is arranged perpendicular to the ore body strike. The stope is mined first, and then the pillar is mined. The mining is fast and the backfilling is fast. The goaf area of ​​the stope near the vertical dividing line is filled with high-concentration backfill material and reinforced with steel bars and metal mesh.

[0026] Preferably, the safe and efficient combined mining method of caving and filling without setting isolation pillars provided by the present invention may also have the following characteristics: In step 4, when the caving method is used for mining, mining is carried out from top to bottom and from the outside away from the vertical dividing line to the side of the vertical dividing line. The multi-segment simultaneous operation is adopted. Each segment of ore body enters the stage transport roadway through the ore pass and is loaded and transported out at the collection point. After the concentrated blasting of ore, the fresh air flow of the segment roadway is forced into the access roadway by the local ventilation fan. The polluted air passes through the segment roadway and the return airway, and then enters the main return air shaft of the mine, and is finally discharged to the surface.

[0027] Preferably, the safe and efficient combined mining method of caving and backfilling without setting isolation pillars provided by the present invention may also have the following features: in step 4, when the backfilling method is used for mining, the width of the stope is the width of one access stop, and the length of the stop is the thickness of the ore body; the width of the pillar is the width of one access stop, and the length of the stop is the thickness of the ore body; rock drilling and blasting adopt a combination of upward fan-shaped medium-deep holes and horizontal holes to cavitate the ore body.

[0028] Preferably, the safe and efficient combined mining method of caving and filling without setting isolation pillars provided by the present invention may also have the following features: in step 3, each step in the vertical dividing line corresponds to a caving method blast hole located at the boundary of a stage, and extends vertically from top to bottom along the inner top of the blast hole and then extends obliquely towards the inner top of the caving method blast hole located at the boundary of the next stage.

[0029] Preferably, the safe and efficient combined mining method for caving and backfilling without the installation of isolation pillars provided by the present invention may also have the following feature: In step 3, the formula for calculating the hanging wall movement angle β is:

[0030]

[0031] In the formula, This is the effective internal friction angle.

[0032] The role and effect of invention

[0033] The present invention provides a safe and efficient combined mining method for caving and backfilling without the need for isolation pillars. This method, while ensuring no surface damage (avoiding further surface subsidence around the subsidence area), rationally divides the mining area for each method by establishing a vertical boundary between caving and backfilling. The ore body on the side where surface structures are located at the vertical boundary is the backfilling mining area, while the ore body on the side away from surface structures is the caving mining area. The edges of the blast holes at each stage are defined at the boundary between the stepped vertical boundary and the caving mining area. The contours overlap, and then the filling method and caving method are used for mining simultaneously. In the caving method mining area, the mining sequence is from the outside away from the vertical boundary line to the side of the vertical boundary line. In the filling method mining area, the mining sequence is from the side of the vertical boundary line to the outside away from the vertical boundary line. Thus, the deep ore body can be safely and efficiently mined without any isolation pillars. Moreover, it not only effectively reduces the amount of residual ore, improves the mine recovery rate, and ensures production capacity, but also guarantees the safety of mining and protects the stability of the surface and the safety of surface structures. Attached Figure Description

[0034] Figure 1 This is a schematic diagram (underground) of the mining process of the safe and efficient combined mining method of caving and filling without setting isolation pillars, which is an embodiment of the present invention.

[0035] Figure 2 This is a partial enlarged view of the vertical dividing line and the arrangement of nearby ore blocks (sub-stages) and blast holes involved in an embodiment of the present invention;

[0036] Figure 3 for Figure 1 Section II;

[0037] Figure 4 for Figure 1 Section II-II;

[0038] Figure 5 This is a schematic diagram illustrating the process of determining the starting point C0 of the vertical dividing line in an embodiment of the present invention.

[0039] In the diagram, 1-Mining sequence of the filling area, 2-Filling body, 3-Ore body, 4-Horizontal blast hole, 5-Vertical boundary line, 6-Stage transport roadway, 7-Mining sequence of the caving area, 8-Fan-shaped blast hole, 9-Sectional drilling ore extraction route, 10-Overburden rock; 11-Sub-area with mining sequence number 7, 12-Sub-area with mining sequence number 20; 13-Upper stage along-vein transport roadway; 14-Cutting riser; 15-Cutting horizontal roadway; 16-Lower stage along-vein transport roadway; 17-Crossing roadway; 18-Ore pass; 19-Equipment shaft connecting roadway; 20-Equipment shaft; 21-Filling riser; 22-Caving method recovery roadway; 23-Ore pass; 24-Personnel ventilation riser; 25-Ore extraction roadway; 26-Connecting roadway between ore extraction roadway and stage transport roadway. Detailed Implementation

[0040] The following describes in detail, with reference to the accompanying drawings, the specific implementation scheme of the safe and efficient combined mining method for caving and filling without setting isolation pillars, which relates to the present invention.

[0041] <Example>

[0042] like Figures 1-5 As shown, in this embodiment, the method of the present invention is used for subsequent mining when the ore body has been mined by caving method to the point where the collapsed area is close to the area where surface buildings are located. The specific steps include the following:

[0043] Step 1: Divide the ore body into multiple mining stages along the vertical direction. Within each stage, arrange transport roadways in each segment. The mining area is connected to the transport roadways of each segment through connecting roadways.

[0044] like Figures 1-4 The ore body 3 is divided into multiple mining stages vertically. Each segment within a stage is equipped with a transport roadway 6. The stope is connected to the transport roadways of each segment via a connecting roadway 26. The mining stages are divided based on the principle that the roof pillars of the upper stage and the lower stage do not overlap. Multiple mining stages can be mined simultaneously. The method for dividing each segment is as follows: based on the classification of the rock mass quality of the ore body, the maximum allowable exposed volume of the stope for different mining methods is evaluated, and the segment height is determined based on the allowable goaf exposure height of the medium-deep hole stope.

[0045] In this embodiment, as Figure 1 As shown, the mining layout and structural parameters are selected as follows: the ore body 3 is divided into six mining stages (six layers) from top to bottom. When it is a narrow and long ore body, the ore blocks (sub-stages) are arranged along the strike of the ore body. When it is a thick and large ore body, the ore blocks are arranged perpendicular to the strike of the ore body. The height is 90-110m, and the height of each segment is 15-20m. A drilling and ore extraction roadway 9 perpendicular to the strike of the ore body is set in the segment. The distance between two adjacent drilling and ore extraction roads is 12-16m.

[0046] Step 2: Preliminary Determination of Mining Method:

[0047] The edge of the area where surface buildings are located is taken as the basic boundary of the surface. Figure 5 Point E in the cross section shown) indicates that the ore body F1, located on the side of the surface building at the surface foundation boundary (underground to be mined), will be mined using the backfilling method, while the ore body F2, located on the other side (underground to be mined), will be mined using the caving method. The two mining methods are highly consistent in stage, and the overall mining sequence is from top to bottom.

[0048] Step 3, as follows Figures 1-2 As shown in Figure 5, the vertical boundary between the two mining methods is determined:

[0049] The values ​​of the translation angle parameters X and Y are calculated using the following formulas:

[0050]

[0051]

[0052] In the formula, α is the dip angle of the ore body, β0 is the initial failure surface movement angle, H0 is the depth of the overlying granular material, H1 is the depth at the end of mining, γ is the unit weight of the hanging wall, c' is the cohesion, and γ c The bulk density of the disintegrating material. K is the internal friction angle between the granular material and the rock mass. p1 K is the coefficient of lateral pressure acting on the initial slip surface. p2 It represents the lateral pressure coefficient acting on the hanging wall surrounding rock.

[0053] Then, based on the movement angle parameters X and Y, the upper plate movement angle β is obtained:

[0054]

[0055] In the formula, This is the effective internal friction angle.

[0056] Furthermore, such as Figure 5 As shown, based on the mining depth H1 and the surface foundation boundary, the boundary line C0 (point on the cross-section diagram) of the ore body is determined, which is located at the top of the underground ore body to be mined and extends from top to bottom towards the side away from the surface building with an angle of β.

[0057] Next, as Figure 1 and 2As shown, on a cross-section perpendicular to the ore entry route: starting from point C0, where the boundary line on the ore body is located, a vertical boundary line C0C1 is formed by extending downwards and in a stepped manner away from the side where surface buildings are located, until the bottom C1 of the final mining stage. The angle of inclination of this vertical boundary line (the angle between C0C1 and the direction of F1) is greater than the rock movement angle and less than 90°. The mining areas for the two mining methods are divided using the vertical boundary line C0C1 as the final boundary. The area located on the side where surface buildings are located at the vertical boundary line C0C1 is F1 (…). Figure 1 The ore body on the left side of C0C1 is a backfill mining area, far from the F2 side where surface buildings are located. Figure 1 The ore body to the right of C0C1 is a caving mining area. The stepped vertical boundary line C0C1 coincides with the edge contours of all stage fan-shaped blast holes 8 at the boundary of the caving mining area. The stepped contours are presented according to the upward fan-shaped hole contours, ensuring the complete contour of the caving blast holes 8. Specifically, each step in the vertical boundary line C0C1 corresponds to a stage caving fan-shaped blast hole 8 located at the boundary, and extends vertically from top to bottom along the inner top of the blast hole 8, and then slopes towards the inner top of the next stage caving blast hole 8 located at the boundary (segmented drilling ore extraction path 9).

[0058] Step 4: Simultaneous mining using both backfilling and caving methods:

[0059] For areas where backfilling is used for mining: such as Figure 1 As shown in the numbers on the left, the backfilling mining area adopts the sequence of mining from the vertical boundary line C0C1 to the outside away from the vertical boundary line C0C1. Figure 1 The mining sequence shown is only a partial illustration and does not depict the complete sequence of all stages. Sub-regions with an area less than one at the boundary of the filling method have the same mining sequence as adjacent sub-regions (e.g., ...). Figure 1 There are two sub-regions with mining sequence number ⑦. There are also two). The ridge remnants near the vertical boundary C0C1 in odd-numbered stages (stages 1, 3, and 5 in this embodiment) are mined by drilling upward fan-shaped holes in even-numbered stages (stages 2, 4, and 6 in this embodiment, sub-stages, for example, sub-regions 11 and 12 in the figure). For the backfilling mining area, each mining sub-stage is set up sequentially from the inside to the outside along the horizontal direction, alternating between stages. For ore bodies near the boundary C0C1 area mined by caving method, pre-splitting blasting is used; for ore bodies near the vertical boundary C0C1 area mined by backfilling method, smooth blasting is used, and the blasting height for backfilling is less than or equal to 3m. When mining using the filling method, the width of the stope is the width of one access stop, and the length of the stop is the thickness of the ore body; the width of the pillar is the width of one access stop, and the length of the stop is the thickness of the ore body. Rock drilling and blasting adopt a combination of upward fan-shaped medium-deep holes and horizontal holes to break down the ore body.

[0060] For areas where caving mining is used: such as Figure 1 As shown in the serial number on the right, the bottomless caving method is adopted. The caving method mining area adopts the sequence of mining from the outside away from the vertical boundary line C0C1 to the side of the vertical boundary line C0C1. Figure 1 The mining sequence shown is only a partial illustration and does not depict the complete sequence of all stages. Within each stage, the mining sub-stages are arranged sequentially along the horizontal direction from the outside to the inside.

[0061] For areas mined using the backfilling method, the ore body is horizontally divided into stops and pillars along the strike of the ore body. A combination of approach backfilling mining and medium-deep hole sublevel backfilling mining is used for extraction. The stops and pillars are arranged perpendicular to the strike of the ore body. Stopes are mined first, followed by pillars, with rapid extraction and backfilling. High-concentration backfill is used to fill the goaf near the vertical boundary C0C1, reinforced with steel bars and metal mesh. When using the caving method, mining proceeds from top to bottom, from the outer side away from the vertical boundary C0C1 towards the C0C1 side. Multiple sections are operated simultaneously. Each section of ore body enters the stage transport roadway via a chute and is loaded and transported out at the collection point. After concentrated blasting, fresh air from the section roadway is forced into the approach roadway using local ventilation fans. Waste air passes through the section roadway and return airway, then enters the main return air shaft and is finally discharged to the surface. During large-scale ore extraction, as ore is continuously mined, the overburden 10 continuously moves downwards to fill the goaf, controlling ground pressure. When mining from the outside in using the caving method, one side consists of caved debris and the other side is the original rock. Near the vertical boundary C0C1 area, one side consists of caved debris and the other side is an artificial pillar formed by filling. During the mining process, large-area goafs are not formed. The original rock, caved debris, and artificial pillars formed by filling support the hanging wall. In the later stages of mining, the filling body 2 in the filling area controls ground pressure, and the overburden above the caving area moves downwards to fill the goaf, controlling ground pressure and creating a safe mining environment.

[0062] Through the above methods, the ground pressure activities are effectively reduced, the work efficiency is improved, and the safety of the ground surface is ensured, providing a safe and efficient mining process for ore mining in the deep high ground stress environment.

[0063] Furthermore, smooth blasting is adopted for the ore body blasting in the area near the filling method adjacent isolation zone, and presplitting blasting is adopted for the ore body blasting in the area near the caving method adjacent isolation zone to avoid disturbing the surrounding rock of the stope. The artificial ore pillars formed by filling and the caved loose bodies in the demarcation area between the two mining methods together constitute a support system to support the upper rock mass, which can effectively ensure the stability of the ground surface. For the ore body on the side of the surface building located on the vertical demarcation line, the drift and stope structure of the filling method ore room and pillar is used, and multiple drifts are mined simultaneously to improve the overall mining efficiency of the ore room; for the ore body on the other side of the vertical demarcation line, the drift and stope structure of the caving method is adopted, and the ore is mined in one step by using the rock drilling and ore drawing drift to avoid the disadvantage of ore loss caused by leaving ore pillars in the traditional open stoping method; after the ore in the adjacent demarcation area is mined, it is filled with a high proportion of cemented filling body and supplemented with steel bars and metal meshes for reinforcement to provide a safer mining environment for the deep stope.

[0064] The above multiple mining stages and sub - stages can be mined simultaneously; the method for dividing the stages is as follows: based on the classification of the rock mass quality of the ore body to be mined, the maximum allowable exposed volume of the stope of different mining methods is evaluated, and the section height is determined based on the allowable height of the goaf exposed in the medium - deep hole stope.

[0065] Specifically, in this embodiment, the rock drilling and ore drawing drifts of two adjacent sections in the caving method mining area are arranged in a "pin" - shaped staggered manner. The filling method mining area 1 adopts the drift and stope structure of ore room and pillar, and the rock drilling drifts of two adjacent sections are arranged in a "zigzag" alignment, and the filling area of each section increases by half of the drift spacing of 6 - 8 m from top to bottom.

[0066] The deep ore body on the F2 side of the vertical demarcation line C0C1 (the ore body in the caving area on the right) is mined by the non - pillar caving method. Each stope is mined in the order marked in the legend (① - ). By reasonably designing the mining sequence and ore block layout, when the caving method gradually mines to near the vertical demarcation line C0C1, the filling body near the vertical demarcation line C0C1 has been maintained to reach the safe strength; the ore drawing efficiency can be improved by adopting the method of multi - section simultaneous operation. The ore bodies of each section also enter the stage transportation roadway 6 through the ore pass 18 and are loaded and transported out at the ore collection point. When large - scale ore drawing is carried out, as the ore is continuously mined, the overlying rock 10 continuously moves down to fill the goaf to control the ground pressure. After centralized blasting for ore drawing, a local ventilation fan is used to press the fresh air flow in the section roadway into the drift, and the polluted air passes through the section roadway and the return airway, and then enters the main return airway 24 of the mine and is finally discharged to the ground surface.

[0067] The deep ore body 1 on the F2 side of the vertical dividing line C0C1 is mined using the backfilling method. Horizontally, along the strike of the ore body, the ore body is divided into stops and pillars. A combination of approach backfilling mining and medium-deep hole sublevel backfilling mining is used for mining. Each stope is marked as shown in the legend (①~). Mining is carried out sequentially. The stops and pillars are arranged perpendicular to the ore body strike, with the stop width being equal to the width of one access stop and the stop length equal to the ore body thickness. The pillar width is equal to the width of one access stop and the stop length equal to the ore body thickness. Rock drilling and blasting adopt a combination of upward fan-shaped medium-deep holes (8 holes) and horizontal holes (4 holes) to break down the ore body. At the boundary of the filling area, the stope width is half the width of the access stop. The ridge residue near the vertical boundary C0C1 of odd-numbered stages is mined by drilling upward fan-shaped holes in the even-numbered stage stopes. The stopes are mined first, followed by the pillars. The goaf near the boundary is filled with high-concentration filling material.

[0068] For ore bodies near the vertical boundary C0C1 area mined using the backfilling method, smooth blasting is employed, with a blasting height of less than or equal to 3 meters. For ore bodies near the vertical boundary C0C1 area mined using the caving method, pre-splitting blasting is employed, with medium-deep hole blasting used in the caving method. The caving method proceeds from the outside in... Figure 1 When mining from right to left, one side is caving debris and the other side is original rock. When approaching the vertical dividing line C0C1 area, one side is caving debris and the other side is an artificial pillar formed by filling. When mining with the filling method from the dividing line outward (left), after approaching the vertical dividing line C0C1 area, both sides are original rock and gradually turn to both sides being filling bodies. When mining in each access stope in the stope and pillar, one side is original rock and the other side is filling body 2. In the subsequent filling mining method of the medium-deep hole in the pillar, both sides of the stope are filling bodies 2.

[0069] Figure 1When using the backfilling method to recover ore bodies to the left of the vertical dividing line C0C1, 1-3 sub-sections are recovered each time. The first step involves mining the stope, then mining every other sub-section. Deep-hole drilling rigs are used to drill upward-facing fan-shaped blast holes within the sub-section drilling roadways, with a row spacing of 1.5-2.0m and a bottom-to-bottom distance of 2.0m. The borehole diameter is Φ76mm. The blasted ore is collected at the bottom of the stope using an electric loader. Fresh air enters the sub-section vein roadway, ore extraction roadway 9, or drilling roadway from the intake air shaft and flows into the stope. After flushing the working face, the stale air returns to the upper return air level through the return air shaft. The mining method employs segmented backfilling, with an approach length of 12-16m. Each stope and pillar is arranged perpendicular to the ore body strike. Loaders collect ore from the stopes and transport it to the pass (18). After stope mining, cemented tailings backfill is used, with an ash-to-sand ratio of 1:4 for adjacent backfill materials at the boundary line, reinforced with steel bars and metal mesh. The ash-to-sand ratio for the backfill material at the bottom of the stope is 1:6, and for the upper part, it is 1:10. The pillars are mined in two stages. After pillar mining, cemented tailings backfill is used. The ash-to-sand ratio for the backfill material at the bottom 8-10m of the segmented pillar is 1:6, and for the remaining part, it is 1:15. Before backfilling, drainage pipes and backfill retaining walls are installed to seal the goaf. Mining proceeds from top to bottom, and from the vertical boundary line C0C1 outwards (to the left).

[0070] The above-mentioned development works include the arrangement of transport roadways 16 in the upper and lower hanging walls of the ore body, and the arrangement of equipment shafts 20 and equipment shaft connecting roadways 19 in the lower hanging wall of the ore body. Both mining methods are used in the above-mentioned development works.

[0071] Mining preparation and cutting engineering: Off-vein mining preparation is adopted, with segmented roadways 9 and ore passes 23 arranged in the footwall of the ore body for transporting ore extracted by the subgrade stope filling method and the subgrade caving method without pillars. The mining and cutting engineering includes segmented roadways 6, drilling roadways 9, cross-vein roadways 17, drilling roadway connecting roadways 26, ore extraction roadways 25, ore extraction access roadways, ore passes 23, ventilation shafts 24, and cutting shafts 14. The segmented roadways are arranged outside the footwall. At the end of the subgrade drilling ore extraction access roadway, a cutting level roadway 15 is excavated along the ore body strike. At an appropriate location in the cutting level roadway 15, a cutting shaft 14 is excavated. Several rows of parallel or fan-shaped blast holes 8 are drilled from the cutting level roadway, using the cutting shaft 14 as the blasting free face to form a cutting groove.

[0072] Mining and Ore Extraction: In the caving method mining area, the caving step distance for each section of the drilling and ore extraction approach is 12-16m. Deep-hole drilling jumbos are used for drilling. Eight fan-shaped blast holes are vertically arranged, with a side angle of 45-55°, a hole length of 8-25m, and a diameter of 55-75mm. Each row of resistance lines is 1.5-2.0m long, and the spacing between rows of blast holes is 2-3m. The blast holes are pre-drilled within the approach, and blasting is carried out in stages. Ammonium nitrate fuel oil (ANFOF) is used, and a non-electric detonating cord detonator system is employed. Electric loader is used for ore extraction. Sectional roadways are set up outside the vein, with the mining approach perpendicular to the ore body strike. Generally, a retreat mining sequence from the hanging wall to the footwall is adopted. For ore bodies thicker than 100m, a retreat mining sequence from the middle of the ore body to both the hanging wall and footwall is adopted. In the backfilling method area, the first step is to mine the stope, and the second step is to mine the pillar. Retreat mining is carried out from the hanging wall to the footwall. In the middle section, mining proceeds from bottom to top, with each extraction consisting of 1-2 sub-sections. After backfilling, the upper sub-sections are mined again until the entire middle section is mined. Deep-hole drilling rigs are used to drill upward-facing fan-shaped blast holes within the sub-section drilling roadways, with a row spacing of 1.5-2.0m and a hole bottom distance of 2.0m. The borehole diameter is Φ76mm. Ammonium nitrate fuel oil and a non-electric detonation system are used for detonation. Two to three rows are blasted at a time, with lateral caving. The blasted ore is collected at the bottom of the stope using an electric loader. For ore bodies near the aforementioned boundary line 5 that are mined using the backfilling method, smooth blasting is used, with a blasting height of less than or equal to 3m. For ore bodies near the aforementioned boundary line that are mined using the caving method, pre-splitting blasting is used, with deep-hole blasting employed in the caving method.

[0073] The mining method employs segmented stope followed by backfilling, utilizing multiple stops simultaneously and employing rapid mining and backfilling to maximize the recovery of usable resources, improve mining efficiency, and protect surface stability and the safety of the backfilled stopes. Adjacent ore bodies are mined using a pillarless sublevel caving method, employing multiple sublevel and multiple mining routes simultaneously to improve ore extraction efficiency and safety, ensuring mine productivity. Simultaneous mining across multiple stopes enhances overall mining efficiency. Based on a predetermined stope mining sequence, earlier stopes create a safe, low-stress, and scalable environment for subsequent stopes, enabling safe and efficient mining of thick ore bodies in high-stress areas.

[0074] Ventilation in the mining area: Fresh air enters the mining area from the intake air shaft into the segmental vein roadway 13, the ore exit roadway 22 or the rock drilling roadway 6. After washing the working face, the polluted air returns to the upper return air level through the return air shaft 24.

[0075] The above embodiments are merely illustrative examples of the technical solutions of the present invention. The safe and efficient combined mining method for caving and backfilling without the installation of isolation pillars involved in the present invention is not limited to the content described in the above embodiments, but is defined by the scope of the claims. Any modifications, additions, or equivalent substitutions made by those skilled in the art based on these embodiments are within the scope of protection claimed by the claims of the present invention.

Claims

1. A safe and efficient combined caving and filling mining method without setting isolation pillars, used for subsequent mining in the case that the ore body is mined by caving method to the area close to the building area of the surface, characterized in that, The method comprises the following steps: Step 1, vertically divide the ore body to be mined into multiple mining stages, and arrange the transport roadway in each sub-section within the stage, and connect each sub-section transport roadway with the mining stope through the connecting roadway; Step 2, preliminarily determine the mining method: Take the edge of the area where the surface building is located as the surface foundation boundary, and take the filling method to mine the ore body on the side of the surface building located on the surface foundation boundary, and take the caving method to mine the ore body on the other side away from the surface building; the stage height of the two mining methods is consistent, and the overall mining sequence is from top to bottom; Step 3, determine the vertical division of the two mining methods: The movement angle parameter is calculated using the following equation X and Y the value of: ， ， wherein α is the angle of the ore body, β 0 is the initial failure surface movement angle, H 0 is the depth of the overlying dispersion, H 1 is the depth at the end of the mining, Then, in the section perpendicular to the ore drawing access: take the point C0 where the upper division line of the ore body is located as the starting point, extend downward and away from the side where the surface building is located in a stepped manner until the bottom C1 of the last mining stage to form the vertical division line C0C1, and the inclination angle of the vertical division line is greater than the rock movement angle; take the vertical division line as the final division to divide the mining areas of the two mining methods, and the ore body on the side of the surface building located on the vertical division line is the filling method mining area, and the ore body away from the side where the surface building is located is the caving method mining area; the stepped vertical division line coincides with the edge profile of each stage blast hole at the boundary of the caving method mining area; is the specific weight of the hanging wall, c’ is the cohesion, Step 4, filling method and caving method mining simultaneously: c is the specific weight of the caving dispersion, is the internal friction angle between the dispersion and the rock mass, K p1 is the lateral pressure coefficient acting on the initial slip surface, K p2 is the lateral pressure coefficient acting on the hanging wall. Then, according to the moving angle parameter X and Y , the upper disc moving angle β is obtained, and further based on the mining depth H 1 and the surface foundation boundary, the upper boundary line of the ore body located at the top of the underground ore body to be mined and having a connecting surface with the surface foundation boundary extending obliquely from top to bottom away from the side where the surface building is located with an angle of β is determined. For the filling method mining area: the filling method mining area adopts the sequence of mining from the side of the vertical division line to the outside of the vertical division line; For the caving method mining area: adopt the sublevel caving method, and the caving method mining area adopts the sequence of mining from the outside of the vertical division line to the side of the vertical division line.

2. The caving and filling safe and efficient combined mining method without setting isolation pillars according to claim 1, wherein: In step 4, the side of the vertical division line is the inside, and the side away from the vertical division line is the outside; for the caving method mining area, each stage is sequentially provided with each mining sub-stage from the outside to the inside along the horizontal direction; for the filling method mining area, each stage is sequentially provided with each mining sub-stage from the inside to the outside along the horizontal direction.

3. The caving and filling safe and efficient combined mining method without setting isolation pillars according to claim 1, wherein: wherein, In step 4, for the filling method mining area, the ridge of the odd stage near the vertical division line is left to be mined by the even stage ore room in a fan-shaped manner.

4. The caving and filling safe and efficient combined mining method without setting isolation pillars according to claim 2, wherein: wherein, In step 4, multiple mining stages and sub-stages can simultaneously carry out mining; in step 1, the division method of each stage is: on the basis of grading the rock mass quality of the ore body to be mined, the maximum allowable exposed volume of the stope of different mining methods is evaluated, and the allowable exposed height of the sublevel caving stope is taken as the basis to determine the sub-section height.

5. The caving and filling safe and efficient combined mining method without setting isolation pillars according to claim 1, wherein: wherein ​ ​ wherein, In step 4, for the ore body near the boundary line area mined by caving method, pre-splitting blasting is used; for the ore body near the vertical boundary line area mined by filling method, smooth blasting is used, and the filling method blasting height is less than or equal to 3m.

6. The caving and filling safe and efficient combined mining method without setting isolation pillars according to claim 1, characterized in that: wherein In step 4, for the area mined by filling method, the ore body to be mined is divided into ore rooms and ore pillars in horizontal direction along the ore body trend, and a drift filling mining method is combined with a medium-length hole sublevel backfill mining method for stoping, each stope in the ore room and ore pillar is arranged vertically to the ore body trend; the ore room is mined first, then the ore pillar is mined, fast mining and fast filling, the ore room goaf near the vertical boundary line is filled with high-density filling body, and is assisted by steel reinforcement and metal mesh reinforcement.

7. The caving and filling safe and efficient combined mining method without setting isolation pillars according to claim 1, characterized in that: wherein In step 4, when caving method is used for mining, mining is carried out from top to bottom and from the outside away from the vertical boundary line to the vertical boundary line side, a multi-segment simultaneous operation mode is used, each segment ore body enters the stage transportation roadway through the chute, and is transported out by loading at the ore collection point; after concentrated blasting and ore falling, a local ventilation fan is used to press the fresh air flow in the segment roadway into the drift, the contaminated air passes through the segment roadway, the air return roadway, and then enters the main air return shaft of the mine, and is finally discharged to the ground.

8. The caving and filling safe and efficient combined mining method without setting isolation pillars according to claim 1, characterized in that: wherein In step 4, when filling method is used for mining, the ore room width is taken as the width of a drift stope, and the stope length is the thickness of the ore body; the ore pillar width is taken as the width of a drift stope, and the stope length is the thickness of the ore body; upward fan-shaped medium-length hole and horizontal hole are combined for rock drilling and blasting to caving the ore body.

9. The caving and filling safe and efficient combined mining method without setting isolation pillars according to claim 1, characterized in that: wherein In step 3, each step of the vertical boundary line corresponds to a stage of the boundary caving method blast hole, and extends vertically along the inside top end of the blast hole and then obliquely to the inside top end of the next stage of the boundary caving method blast hole from top to bottom.

10. The caving and filling safe and efficient combined mining method without setting isolation pillars according to claim 1, characterized in that: wherein, In step 3, the upper disc moving angle β The calculation formula is: ， In the formula, is the effective internal friction angle.

Images