A method of mining a multi-seam fractured rock mass

Abstract

This invention discloses a mining method for multi-layered fractured rock masses, comprising the following steps: determining the constituent elements of the ore block; arranging preparatory works according to the constituent elements of the ore block, placing the preparatory works in the footwall and vein of the ore body; independently cutting and pulling different ore layers, with the upper section advancing the lower section during construction; pre-controlling the roof support of the stope, and implementing differentiated support according to different mining sections and surrounding rock conditions; and carrying out mining operations, wherein the mining operations are performed in the order of mining the footwall ore body first, followed by mining the hanging wall ore body, and the footwall ore body mining and filling operations advance the hanging wall ore body by at least one section. This invention, while ensuring stope safety, achieves mechanized, large-scale, high-efficiency, and low-cost mining of multi-layered fractured ore bodies, overcoming the contradiction between stope stability and production capacity that is difficult to balance in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of mining technology, and in particular to a method for mining multi-layered fractured rock masses. Background Technology

[0002] For mining conditions involving multiple ore layers and fractured rock masses, traditional methods mainly include upward-entry backfilling mining, downward-layered backfilling mining, and downward-sublevel backfilling mining. Among these, upward-entry backfilling mining is a commonly used method for handling fractured ore bodies, offering advantages such as strong adaptability, small exposed mining area, good ground pressure control, and high ore recovery rate. However, it suffers from limitations such as high production costs, low production efficiency, difficult ventilation, and complex processes, making large-scale mechanized operations difficult and generally only applicable to precious metal mines. Downward-layered backfilling mining operates under a false roof formed by cemented backfill, offering high safety and single-step mining without the need for pillars. Ore loss can be controlled at an extremely low level of 3% to 5%. However, its process is extremely complex, one of the most complex of all mining methods, resulting in low block production capacity, low worker productivity, and high mining costs. Downward sublevel backfilling mining can significantly improve mining efficiency when combined with highly efficient mechanized equipment, but it requires operation at the bottom of the backfill body, demands high strength from the backfill body, and necessitates precise control of blasting operations, making it quite difficult to operate. Based on the above methods, a further optimization has led to the pre-cutting roof sublevel open-stope backfilling mining method. By pre-supporting the roof before mining, the roof of the stope can be controlled, significantly improving safety and mining efficiency. However, for multi-layered fractured ore bodies, this method still lacks clear technical solutions for mining process layout and stope structure design.

[0003] Therefore, there is an urgent need to provide a solution for mining multi-layered fractured rock masses. Summary of the Invention

[0004] To address the above problems, the present invention provides a mining method for multi-layered fractured rock masses. By rationally arranging the development, preparation, cutting, and recovery operations of different ore layers, it achieves safe and efficient mining of different ore layers. At the same time, it applies pre-support to the roof to further improve the safety of mining operations, realizes mechanized and efficient mining, and improves the production capacity and recovery rate of the mining area. It has extremely high application value in the field of mining technology.

[0005] According to a first aspect of the present invention, a method for mining multi-layered fractured rock masses is provided, comprising the following steps: S1. Determine the constituent elements of the ore block, including the panel size, ore block layout, stope layout, and pillar size; S2. Arrange the mining preparation works according to the constituent elements of the ore block. The mining preparation works are arranged in the footwall and vein of the ore body, wherein the mining preparation works of the ore layer near the footwall are arranged in the footwall of the ore body, and the mining preparation works of the ore body near the hanging wall are arranged in the vein. S3. After the mining preparation project is completed, the cutting and pulling work is carried out. The cutting and pulling work is carried out independently for different ore layers, and the upper section is constructed in advance of the lower section. S4. After the cutting and pulling of the bottom is completed, the pre-control operation of the mining area is carried out to support the roof of the mining area and to carry out differentiated support according to different mining sections and surrounding rock conditions. S5. After the pre-control roof operation is completed, the mining operation is carried out. The mining operation is carried out in the order of mining the lower ore body first and then mining the upper ore body. The mining and filling operation of the lower ore body is at least one segment ahead of the upper ore body. The mining operation includes rock drilling and blasting, stope ventilation, ore extraction and stope filling.

[0006] In the above scheme, step S1: The length of the panel is set to 100~120 m, the height is set to 50~80 m, and it is divided into 2~4 segments; Within the panel, each mineral layer is divided into 1 to 2 mineral blocks along its length. The length of each mineral block is determined by the length of the panel and the number of mineral blocks. Within the panel, several mining areas are divided along the length of each ore layer. The length of the mining area is equal to the thickness of the ore body, and the width is set according to the geological conditions of the ore and rock. One to two mining blocks of the same size are left between the panels as mining channels for the upper ore body.

[0007] In the above scheme, step S2 includes: External segmented roadways are arranged in the footwall surrounding rock, 10-20 m away from the footwall ore body, and connected by inclined ramps; In each stope, a separate rock drilling roadway perpendicular to the strike of the ore body is arranged in the footwall ore layer, which also serves as the mining roadway; Multiple vein tunnels are arranged within the column section of the panel. Each section is equipped with a vein tunnel, which is perpendicular to the strike of the ore body and has a length equal to the thickness of the ore body. Along the strike of the hanging wall ore body, a vein-connecting tunnel is arranged within the ore body on the side closest to the hanging wall. The length of the tunnel is the length of the hanging wall area, and it serves as both a drilling tunnel and an ore extraction tunnel. Cutting wells with a diameter of 2-4 m are arranged at the end of the mining area; Cutting tunnels are arranged within the ore body and connected to cutting risers to form an initial blasting free face with sufficient width and height; Arrange the lower and upper ore passes, with a horizontal distance of 10-15 m between them and a diameter of 3 m for each; Arrange connecting passages between the chute and the segmented roadways.

[0008] In the above scheme, step S3 includes: The lower ore layer is cut into the ore body through drilling roadways, the bottom of the upper sub-mining is opened and supported in time, and then the cutting riser is constructed. The upper ore layer is cut into the ore body through the vein roadway in the upper ore body, the bottom of the upper sub-mining is opened and supported in time, and then the cutting riser is excavated to connect with the pre-top layer. The bottom-laying operation was carried out entirely using smooth blasting excavation.

[0009] In the above scheme, step S4: The pre-controlled top support adopts a combination of anchor mesh and anchor bolts. The anchor bolt mesh is 2 m × 2 m in size, the anchor bolt diameter is 20 mm, and the length is 1.5~3 m. The anchor mesh is 2 m × 2 m in size and the diameter is 6~10 mm. Differentiated support methods are implemented based on different mining sections and surrounding rock conditions, including: for the first mining section, anchor bolt support is used, and for other sections, a combination of anchor mesh and anchor bolt support is used. For areas of the hanging wall ore layer near the hanging wall fracture zone, anchor cables are used for reinforcement. The anchor cables pass through the hanging wall fault zone for 3-4 m and are arranged perpendicular to the hanging wall fracture surface.

[0010] In the above scheme, the rock drilling and blasting operations in step S5 include: A medium-deep hole drilling rig was used to drill downward fan-shaped medium-deep holes. The spacing of the first row of blast holes near the cutting well is set to 0.5 to 0.7 times the minimum resistance line of normal rock drilling. Emulsion explosives are used, and the explosives are loaded mechanically using a loading trolley; At the time of detonation, a row of holes is blasted separately on the free face of the cutting well and the cutting level. Subsequently, 2 to 3 rows of blast holes are blasted each time, and digital detonators are used to carry out micro-delay blasting.

[0011] In the above scheme, the ventilation operation in step S5 includes: Ventilation of the footwall: Fresh air enters the footwall from the auxiliary shaft through the intermediate transport roadway, the section roadway, and the rock drilling roadway, and then exits to the surface through the return air roadway and the return air shaft; Ventilation of the hanging wall: Local fans are installed in the pillar-crossing roadways between the hanging wall and the hanging wall. Fresh air flows through the auxiliary shaft, intermediate transport roadway, segment roadway, pillar-crossing roadway between the hanging wall and the hanging wall ore layer along the vein into the hanging wall. Stale air enters the return air shaft through the return air roadway and is discharged to the surface.

[0012] In the above scheme, the ore extraction operation in step S5 includes: Ore extraction from the lower ore layer: Ore is transported from the lower ore layer extraction route to the lower ore layer pass via segmented roadways; Ore extraction from the hanging ore layer: Ore is transported from the hanging ore layer along the vein roadway, through the inter-plate pillar vein roadway and segmented roadway to the hanging ore layer pass; During the mining process, the frequency and size of falling rocks from the roof are used to assess safety.

[0013] In the above scheme, the stope backfilling operation in step S5 includes: Filling retaining walls were built at the ore inlet of the lower ore layer and in the vein roadway of the upper ore layer. The stope filling is carried out in 3 to 4 stages to fill the goaf. The interval between each filling is 10 to 14 hours after the initial setting time of the filling body. The height of the first filling is higher than the roof of the rock drilling and ore extraction roadway. The filling material adopts a layered filling method with high strength at the bottom and normal strength in the middle; The filling slurry is dewatered by pre-laying filter pipes in the mining area, and the filter pipes are not recycled.

[0014] In the above scheme, in step S5, during the mining operation, the footwall ore body is mined backward from the side closer to the hanging wall ore body to the side closer to the footwall surrounding rock, and the hanging wall ore body is mined backward from the center of the panel to both sides.

[0015] The beneficial effects of this invention are: Significantly improves the stability and safety of mining operations: By adopting the roof pre-control technology of "pre-cutting roof + anchor mesh and bolt combined support", and implementing differentiated support according to different sections and areas, the risk of damage to the roof of the fractured ore body is effectively controlled, and the collapse of the roof or hanging wall is avoided, which greatly improves the safety of mining operations.

[0016] To achieve efficient and coordinated mining of multiple ore layers: a layered mining mode of "mining the lower ore body first and then mining the upper ore body" is adopted, and the mining and filling operations of the lower ore body are 1-2 sections ahead of the upper ore body, forming a rolling operation cycle of "mining-filling-mining", which avoids mutual interference between the mining of the upper and lower ore bodies and ensures the continuity and high efficiency of the mining operation.

[0017] Significantly improves production capacity and recovery rate: The panel is rationally divided, and the mining area adopts mechanized equipment such as medium-deep hole drilling rigs, charging rigs, and remote-controlled loaders to achieve large-scale and high-efficiency mining operations; the pillars between panels are mined after the ore is mined out, maximizing the recovery of ore resources and resulting in a high recovery rate.

[0018] To adapt to the geological conditions of the fractured ore body and reduce mining costs: the footwall ore body adopts an off-vein preparation engineering layout, while the hanging wall ore body adopts a combination of on-vein and off-vein layout, making full use of the pillars in the hanging wall as the back mining channel, thus reducing a large amount of preparation engineering; at the same time, it avoids the complex process of traditional downward layered backfilling mining method, thereby reducing mining costs.

[0019] Effective control of the exposed area of ​​ore and rock, and ensuring the stability of the backfill: Through the intermittent mining of the footwall ore body, the retreat mining of the hanging wall ore body, and the strict control of the blasting row spacing (intensified first row, 2-3 rows blasted each time), the instantaneous exposed area of ​​the stope roof is limited; after the footwall goaf is backfilled, the hanging wall ore body is mined again, and the backfill serves as support for the backfilling of the hanging wall, further ensuring the stability of the overall stope structure.

[0020] The ventilation system is independent and reliable, and the working environment is excellent: the lower and upper mining areas are designed with independent ventilation routes. The upper mining area uses the inter-panel pillar cross-vein roadway to arrange local fans to form a complete cycle of fresh air flow-working face-sludge air, which effectively solves the problem of ventilation difficulties in mining multi-layered fractured ore bodies and improves the underground working environment.

[0021] The filling process is reasonable and the strength of the filling body is controllable in layers: 3 to 4 layers of filling are adopted. The height of the first filling is higher than the roof of the rock drilling and mining roadway. The filling body adopts a layered design with high strength at the bottom and normal strength in the middle. This not only ensures the bearing capacity of the bottom mining roadway, but also saves the amount of high-grade filling material. At the same time, filter pipes are laid in advance for dewatering. The filter pipes are not recycled, which simplifies the filling process.

[0022] It has wide adaptability to fractured roofs: parameters such as bolt mesh size, bolt length, and bolt cable arrangement can be adjusted according to the degree of fracture of the ore body. All bottom pulling operations adopt smooth blasting to minimize the disturbance of the roof to the blasting. It is suitable for multi-layered fractured ore bodies with different stability levels.

[0023] In summary, this invention, while ensuring the safety of the mining site, realizes mechanized, large-scale, efficient, and low-cost mining of multi-layered crushed ore bodies, overcoming the contradiction between mining site stability and production capacity that is difficult to balance in existing technologies, and has extremely high industrial application value. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0025] Figure 1 This is a flowchart of the multi-layered fractured rock mining method of the present invention; Figure 2a This is a front cross-sectional view of the footwall ore seam mining method I-I of the present invention; Figure 2b This is a top cross-sectional view of the footwall ore seam mining method II-II of the present invention; Figure 2cThis is a side cross-sectional view of the footwall ore mining method III-III of the present invention; Figure 3a This is a side cross-sectional view of the upper ore layer mining method I-I of the present invention; Figure 3b This is a side cross-sectional view of the upper ore layer mining method II-II of the present invention; Figure 3c This is a side cross-sectional view of the upper ore layer mining method III-III of the present invention.

[0026] Among them, 1-a and b layer ore vein roadways; 2-a layer ore exit roadway; 3-downward fan-shaped medium-deep borehole; 4-“anchor mesh + anchor bolt” combined support; 5-a layer ore drilling roadway; 6-a layer ore pass; 7-b layer ore pass; 8-filling body; 9-a layer ore pass connecting roadway; 10-filling return air shaft; 11-intermediate transport roadway; 12-external segment roadway; 13-filling retaining wall; 14-b layer ore pass connecting roadway; 15-person ventilation shaft; 16-cutting horizontal roadway; 17-sloping ramp; 18-a layer ore; 19-b layer ore; 20-panel inter-section pillar; 21-b layer ore vein roadway; 22-cutting shaft; 23-anchor cable.

[0027] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0028] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0029] The terms "first," "second," etc., used in this disclosure are for distinguishing similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that the embodiments of this disclosure described herein can be implemented, for example, in orders other than those illustrated or described herein.

[0030] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0031] Multiple, including two or more.

[0032] And / or, it should be understood that, for the purposes of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0033] like Figure 1 As shown, one embodiment of the technical solution of the present invention provides a method for mining multi-ore-layer fractured rock mass, including the following steps: S1. Determine the constituent elements of the ore block. The constituent elements of the ore block include the panel size, ore block layout, stope layout, and pillar dimensions. Preferably, the specific parameters are as follows: The length of the panel is set to 100~120 m, the height is set to 50~80 m, and it is divided into 2~4 segments; Within the panel, each mineral layer is divided into 1 to 2 mineral blocks along its length. The length of each mineral block is determined by the length of the panel and the number of mineral blocks. Within the panel, several mining areas are divided along the length of each ore layer. The length of the mining area is equal to the thickness of the ore body, and the width is set according to the geological conditions of the ore and rock. One to two mining blocks of the same size are left between the panels as mining channels for the upper ore body.

[0034] The dimensions of the panel, ore block, stope, and pillars in this invention not only ensure the space requirements for mechanized mining but also control ground pressure through the pillars. The pillars also serve as mining channels for the hanging wall ore body, laying the foundation for subsequent preparatory work.

[0035] S2. Arrange the preparatory works according to the constituent elements of the ore block. The preparatory works are arranged in the footwall and vein of the ore body, wherein the preparatory works for the ore layers closer to the footwall are arranged in the footwall, and the preparatory works for the ore body closer to the hanging wall are arranged in the vein. The preparatory works include the external segment roadways, footwall ore layer drilling roadways, multi-ore layer cross-vein roadways, hanging wall ore layer vein-along roadways, cutting risers, cutting adits, footwall ore layer ore pass, hanging wall ore layer ore pass, and ore pass connecting roadways, as detailed below: External segment roadways: These are located in the footwall surrounding rock 10-20 m away from the footwall ore body and are connected to each segment by inclined ramps.

[0036] Footwall ore drilling roadway: Located in the footwall surrounding rock close to the footwall ore body, perpendicular to the strike of the ore body, one roadway is arranged separately in each stope, serving as both a drilling roadway and an ore extraction roadway.

[0037] Multi-ore-layer cross-vein roadways: These are arranged in the pillars between panels, and are located in each section. They are perpendicular to the strike of the ore body and have a length equal to the thickness of the ore body.

[0038] Hanging ore body along the vein: It is arranged in the ore body on the side of the hanging ore body close to the hanging ore body, along the strike of the ore body, and its length is the length of the hanging ore body. It will then serve as the drilling roadway and ore extraction roadway of the hanging ore body.

[0039] Cutting risers: Located at the end of the mining area, with a diameter of 2-4 m, they are formed by drilling into the ore body through rock-drilling tunnels.

[0040] Cutting tunnel: Located within the ore body, it connects with the cutting riser to form the initial blasting free face.

[0041] Lower plate ore pass: Located in the stage roadway, running from the previous stage to the next stage. One or two panels share one set. The diameter is set according to the ore extraction capacity, generally 3 m.

[0042] Upper ore pass: Located in the stage roadway, at a horizontal distance of 10-15 m from the lower ore pass, with a diameter of 3 m.

[0043] Catch connection tunnel: connects the chute and the segment tunnels, and its length is the horizontal distance between the segment tunnels and the stage tunnels.

[0044] This invention arranges the lower plate outside the vein to avoid damage to the roadway during mining and improve the stability of the preparation process; it combines the upper plate inside and outside the vein, using the inter-pillar cross-vein roadway as a connecting channel to reduce the amount of work done purely outside the vein. The drilling roadway and the ore extraction roadway are integrated, simplifying the process. Cutting risers and cutting levelways provide free faces for subsequent blasting. The upper and lower plate ore passes are set up separately to avoid ore mixing, and the reasonable spacing meets transportation requirements.

[0045] S3. After the mining preparation project is completed, the cutting and pulling work is carried out. The cutting and pulling work is carried out independently for different ore layers, and the upper section is constructed in advance of the lower section. The lower ore layer cutting and bottom pulling operation involves constructing a cutting level roadway in the lower ore body through a rock drilling roadway. The cutting level roadway is used to pull open the bottom of the upper sub-mining and provide timely support. After the bottom is completely pulled out and supported, a cutting riser is constructed at the pre-blasted location.

[0046] The upper ore layer cutting and lowering operation involves cutting into the ore body through the vein roadway in the upper ore layer, opening up the bottom of the upper sub-mining, and then providing timely support. After support, a cutting riser is excavated at the corresponding position to connect with the pre-top layer at the bottom of the mining area.

[0047] The excavation method control adopts smooth blasting for all bottom pulling operations to reduce the blasting impact on the ore roof and improve the stability of the stope roof.

[0048] Furthermore, a medium-deep hole cutting groove drilling rig is used to complete the well in one blast, thereby improving cutting efficiency.

[0049] This invention employs an upper-segment, lower-segment approach to ensure continuity between preparation and cutting, avoiding interference between processes. Smooth blasting protects the integrity of the roof and reduces disturbance to the fractured rock mass. Timely support prevents roof collapse after cutting, providing a safe working space for subsequent roof control operations. The cutting well and floor-pulling space formed after cutting and floor-pulling create favorable initial conditions for roof control support and subsequent mining blasting.

[0050] S4. After the cutting and pulling of the bottom is completed, the pre-control operation of the mining area is carried out to support the roof of the mining area and to carry out differentiated support according to different mining sections and surrounding rock conditions. The pre-controlled top support adopts a combination of anchor mesh and anchor bolts. The anchor bolt mesh is 2 m × 2 m in size, the anchor bolt diameter is 20 mm, and the length is 1.5~3 m. The anchor mesh is 2 m × 2 m in size and the diameter is 6~10 mm. Differentiated support methods based on different mining sections and surrounding rock conditions include: For the first mining section of each ore layer, namely the first section, since it serves as the roof for ore mining but has a short exposure time, only anchor bolt support is required.

[0051] For other sections, which need to serve as the ore roof for the next section's mining, the exposed area is large and the exposure time is long, requiring combined support of anchor mesh and anchor bolts.

[0052] For areas of the hanging wall ore layer near the hanging wall fracture zone, anchor cables are used for reinforcement. The anchor cables pass through the hanging wall fault zone for 3-4 m and are arranged perpendicular to the hanging wall fracture surface to give full play to the suspension function of the anchor cables.

[0053] During construction, after the cut section is formed, anchor bolts and steel mesh are installed according to the design. The anchor bolts with trays hold the steel mesh in place, making it tightly attached to the top slab.

[0054] This invention proactively reinforces the roof during pre-control roof operations, transforming passive support into active control and effectively preventing roof collapse during mining. Differentiated support saves costs while ensuring the safety of critical areas.

[0055] S5. After the pre-control roof operation is completed, the mining operation is carried out. The mining operation is carried out in the order of mining the footwall ore body first and then mining the hanging wall ore body, and the mining and filling operation of the footwall ore body precedes the hanging wall ore body by at least one section. During the mining operation, the footwall ore body is mined backward from the side closer to the hanging wall ore body to the side closer to the footwall surrounding rock, and the hanging wall ore body is mined backward from the center of the panel to both sides. The mining operation includes rock drilling and blasting, stope ventilation, ore extraction and stope filling.

[0056] Rock drilling and blasting operations include: A medium-deep hole drilling rig was used to drill downward fan-shaped medium-deep holes. The borehole diameter was determined based on the lithological conditions and equipment, and the minimum resistance line was determined by the borehole diameter.

[0057] The first row of blast holes near the cutting well is densely arranged, with the row spacing set at 0.5 to 0.7 times the minimum resistance line of normal rock drilling, in order to optimize the free surface conditions and ensure full blasting.

[0058] Emulsion explosives are used, and mechanized charging is performed via a charging trolley. During detonation, the existing cutting face and cutting level are used as the initial free face for a single row of blasts, creating favorable conditions for subsequent blasts. After entering the normal mining cycle, 2-3 rows of blast holes are detonated each time, using digital detonators to perform micro-delay blasting on downward fan-shaped medium-deep holes.

[0059] Densifying the number of blast holes in the first row helps overcome the clamping effect at the cutting ceiling; detonating 2-3 rows of blast holes each time ensures blasting efficiency while controlling the exposed area at one time; micro-delay blasting reduces blasting vibration and protects the roof.

[0060] Mining area ventilation operations include: Independent ventilation routes are set up for the lower and upper mining areas respectively.

[0061] Ventilation of the footwall: Fresh air enters the intermediate transport roadway from the auxiliary shaft, then enters the footwall mining area through the segmented roadway and the rock drilling roadway, passes the working face, enters the return air shaft through the return air roadway, and is then discharged to the surface.

[0062] Ventilation in the hanging wall: Local fans are installed in the cross-cutting roadways between the hanging wall and the pillars to deliver fresh air into the stope along the following route: auxiliary shaft → intermediate transport roadway → section roadway → cross-cutting roadway between the hanging wall and the pillars → hanging wall ore seam along the vein → hanging wall ore seam stope. After passing the working face, the stale air enters the return airway in the opposite direction and is discharged to the surface from the return air shaft.

[0063] Independent ventilation is adopted for the upper and lower sections to avoid cross-contamination of polluted air; local fans are arranged in the inter-column cross-vein roadway to make full use of the existing project and eliminate the need for additional ventilation roadway excavation.

[0064] Ore extraction operations include: After the blasting and ventilation of the ore body are completed, the ore extraction operation will be carried out.

[0065] Ore extraction from the lower ore layer: Ore is transported directly from the lower ore layer through segmented roadways to the lower ore layer pass.

[0066] Ore extraction from the hanging wall: Ore is transported from the hanging wall ore layer along the vein roadway, through the inter-plate pillar vein roadway and segmented roadway to the hanging wall ore pass.

[0067] During ore extraction, attention must be paid to the safety below the goaf, which can be judged by observing the frequency and size of roof rock falls. If roof support fails, metal mesh can be covered on the remote-controlled loader for protection. At the same time, personnel should be stationed outside the stope to monitor the ore body prone to roof collapse to prevent the loader from being damaged by the collapsing ore body.

[0068] The upper and lower ore plates are transported separately to avoid mixing of grades; the remote-controlled loader is protected with a metal mesh to improve operational safety under extreme conditions.

[0069] The stope backfilling operation includes: After the mining operation is completed, backfilling should be carried out immediately.

[0070] First, construct the filling retaining wall: the lower ore layer is constructed at the ore inlet, and the upper ore layer is arranged in the vein roadway.

[0071] The stope filling is carried out in 3 to 4 stages to fill the goaf, with the interval between each filling being the initial setting time of the filling body (approximately 10 to 14 hours). The height of the first filling should be higher than the roof of the drilling and ore extraction roadway to ensure the stability of the bottom structure.

[0072] The filling material adopts a layered filling method with high strength at the bottom and normal strength in the middle. The high-strength filling material at the bottom can withstand the rolling and blasting vibrations of subsequent ore extraction equipment; the normal-strength filling material in the middle saves costs.

[0073] Dewatering of the filling slurry is carried out by pre-laying filter pipes in the mining area, and the filter pipes are not recycled later.

[0074] This invention employs layered filling to control the strength distribution of the filling body, ensuring both load-bearing capacity and material savings; the first filling extends above the roadway roof to ensure compact filling around the roadway; and the filter pipe provides simple and effective dewatering.

[0075] Example A specific embodiment of the mining method for multi-layered fractured rock masses provided by the present invention is as follows: The mining method includes the constituent elements of the ore block, preparation engineering, cutting and lowering work, pre-control of the roof in the stope, and mining operations. The constituent elements of a ore block include panel size, block layout, stope layout, and pillar size. The dimensions of the disk area include its length, width, and height.

[0076] like Figure 2a , 2b As shown in Figure 2c, the length of the panel is set to 100 m, and the width is equal to the thickness of the ore body. Among them, layer a ore 18 is 13 m, layer b ore 19 is 15 m, and the height is 60 m. It is divided into 3 segments with a segment height of 20 m. Layer a ore 18 is close to the lower plate, and layer b ore 19 is close to the upper plate.

[0077] The ore blocks are arranged along the strike. Within the panel, each ore layer is divided into two blocks along the length direction. The length of each block is 50 m, and the width of the block is equal to the thickness of the ore body. For layer a, ore 18, the width is 13 m, and for layer b, ore 19, the width is 15 m. The height is the segment height of 20 m.

[0078] The mining area is located within the panel area, and is divided into 5 mining areas along the length of each ore layer. The length of the mining area is equal to the thickness of the ore body. For ore layer 18, it is 13 m, and for ore layer 19, it is 15 m. The width of the first and second step mining areas is 10 m, and the height is 20 m, which is the segment height.

[0079] Inter-panel pillars 20 are provided between the pan areas. Inter-panel pillars 20 serve as channels to enter the b-layer ore 19. The length of the inter-panel pillars 20 is equal to the thickness of the a-layer ore 18 and the b-layer ore 19, totaling 28 m. The width is 10-12 m, and the height is 60 m, which is the height of the pan area. After the ore is mined out, the inter-panel pillars 20 will be mined out.

[0080] like Figure 3a , 3b As shown in 3c, the mining preparation project includes an external segment roadway 12, a-layer ore drilling roadway 5, a and b-layer ore vein crossing roadway 1, b-layer ore vein-along roadway 21, cutting riser 22, cutting level roadway 16, a-layer ore ore pass 6, b-layer ore ore pass 7, and ore pass connecting roadway 9.

[0081] The preparation works are mainly arranged in the footwall and vein of the ore body. The preparation works for layer a ore 18 are arranged in the footwall of the ore body, and the preparation works for layer b ore 19 are arranged in the vein.

[0082] The external segment roadway 12 is located in the footwall surrounding rock 10-20 m away from the a-layer ore body 18, and is connected by a ramp 17.

[0083] The drilling roadway 5 of the a-layer ore is arranged in the footwall surrounding rock near the ore body 18 of the a-layer ore, perpendicular to the strike of the ore body. Each stop has a separate drilling roadway, which serves as both a drilling roadway and an ore extraction roadway.

[0084] The vein-crossing roadways 1 of the a and b layers are arranged in the inter-panel pillars 20 left between the panels. Each segment is equipped with a vein-crossing roadway, perpendicular to the strike of the ore body, and with a length equal to the thickness of the ore body 28 m.

[0085] The vein roadway 21 of the b-layer ore is arranged in the ore body near the hanging wall of the b-layer ore 19, along the strike of the ore body, with a length of 100 m equal to the length of the hanging wall, and subsequently serves as the drilling roadway and ore extraction roadway of the b-layer ore 19.

[0086] The cutting riser 22 is located at the end of the mining area, with a diameter of 2-4 m, and is formed by drilling into the ore body through a rock drilling roadway.

[0087] The cutting tunnel 16 is arranged within the ore body and is connected to the cutting riser 22 to form an initial blasting free face with sufficient width and height.

[0088] The a-layer ore chute 6 is arranged in the stage roadway, running from the previous stage to the next stage. One or two panels share a set of chutes. The chute diameter is 3 m. The a-layer ore chute 6 is connected to the external segment roadway 12 through the a-layer ore chute connecting roadway 9.

[0089] The ore chute 7 of the B-layer ore is located in the intermediate transport roadway 11, running from the previous stage to the next stage. It is 10-15 m away from the ore chute 6 of the A-layer ore and has a diameter of 3 m. The ore chute 7 of the B-layer ore is connected to the segment roadway 12 outside the vein through the ore chute connecting roadway 14 of the B-layer ore.

[0090] The connecting roadway 9 of the a-layer mine ore pass and the connecting roadway 14 of the b-layer mine ore pass mainly connect the ore pass and the segment roadway, and their length is the horizontal distance between the external segment roadway 12 and the intermediate transport roadway 11.

[0091] The cutting and pulling-down work includes operation sequence control, equipment selection and application, cutting and pulling down of layer A ore, cutting and pulling down of layer B ore, and control of excavation method.

[0092] The work sequence control is for layer a ore 18 and layer b ore 19. The cutting and lowering operations are carried out separately and independently, and the overall construction sequence follows the principle of the upper section leading the lower section.

[0093] The equipment and application use the AT-4000L medium-deep hole cutting groove drilling rig, which can form a well in one blast, thereby improving the cutting efficiency. The drilling depth of the medium-deep hole cutting groove drilling rig is 0~400 m, the drilling diameter is 1.8~4 m, the drilling angle is 45~90°, and the working water pressure is 0.8~1.2 MPa.

[0094] The cutting and lowering operation of the A-layer ore 18 involves constructing a cutting horizontal tunnel into the A-layer ore 18 through a rock drilling roadway. The cutting horizontal tunnel 16 is used to open up the bottom of the upper sub-section mining area and provide timely support. After the bottom is completely opened up and supported, the cutting riser 22 is constructed at the pre-blasted location.

[0095] The cutting and lowering operation of the B-layer ore 19 involves cutting into the B-layer ore body through the vein roadway 21 along the B-layer ore, opening up the bottom of the upper sub-section stope, providing timely support after opening, and then excavating and cutting the riser 22 at the corresponding position to connect with the pre-top layer at the bottom of the stope.

[0096] The excavation method control adopts smooth blasting for all bottom pulling operations to reduce the blasting impact on the ore roof and improve the stability of the stope roof.

[0097] The pre-control roof operation in the mining area includes pre-control roof support methods and differentiated support methods for different areas.

[0098] The pre-controlled roof support method mainly adopts the "anchor mesh + anchor rod" combined support method 4. Different support methods can be adopted for different ore layers with different mechanical conditions. For the relatively broken roof or the B layer ore 19 area, anchor cables can be used for support.

[0099] The differentiated support methods for different regions are mainly for different mining sections. For the first mining sections of layer a ore 18 and layer b ore 19, since they supplement the roof of the ore mining, only anchor bolt support is needed. For other sections, which need to serve as the roof of the ore mining of the next section, "anchor mesh + anchor bolt" combined support 4 is required. At the same time, according to the surrounding rock conditions, anchor cables 23 are arranged near the hanging wall to reinforce the hanging wall.

[0100] The pre-controlled top support anchor bolt grid is determined by the degree of ore body fracture, generally around 2 m × 2 m. The anchor bolts are resin anchor bolts made of threaded steel and using resin anchoring agent. The anchor bolt diameter is about 20 mm and the length is 1.5~3 m. The anchor bolt support spacing is adjusted according to the ore body fracture conditions.

[0101] The anchor mesh has a mesh size of 2 m × 2 m and a diameter of 6 mm.

[0102] During the pre-controlled roof construction, after the cut section is formed, the anchor bolts and steel mesh are installed according to the design. The anchor bolts with trays hold the steel mesh in place, making it close to the roof slab.

[0103] The B-layer ore 19 is reinforced near the hanging wall fracture zone by anchor cables 23. The anchor cables pass through the hanging wall fault zone for 3-4m and are arranged perpendicular to the hanging wall fracture surface to give full play to the suspension function of the anchor cables, making the hanging wall more stable during the mining of the B-layer ore.

[0104] The mining operations include rock drilling and blasting, stope ventilation, stope ore extraction, and stope backfilling.

[0105] The overall mining operation follows the principle of mining layer 18 ahead of layer 19, and mining layer 18 in 1-2 stages before mining layer 19.

[0106] In the mining operation, the a-layer ore 18 is mined from near the b-layer ore 19 towards the a-layer ore 18, and the b-layer ore 19 is mined from the center of the panel towards both sides.

[0107] The rock drilling operation was carried out using a CYTC76 medium-deep hole drilling rig, drilling downward fan-shaped medium-deep holes 3. The drilling diameter of the medium-deep hole drilling rig was 64~89 mm, the drill rod length was 1525 mm, the blast hole diameter was 70 mm, and the minimum resistance line was 1.5~1.8 m.

[0108] The rock drilling operation is carried out with denser arrangement at the first row of blast holes near the cutting well 22. The row spacing is set to 0.5 to 0.7 times the minimum resistance line of normal rock drilling, that is, 0.8 to 1.5 m, to optimize the free surface conditions and ensure sufficient blasting.

[0109] The blasting operation uses emulsion explosives, which are loaded mechanically using a loading trolley.

[0110] When the blasting operation is initiated, the existing cutting headhole 22 and cutting level 16 are used as the initial free face to blast a row of holes separately to create favorable conditions for subsequent blasting. After entering the normal mining cycle, 2 to 3 rows of blast holes are blasted each time, and digital detonators are used to carry out micro-differential blasting on the downward fan-shaped medium-deep holes 3.

[0111] The ventilation operations in the mining area are divided into ventilation operations for layer a (18) and ventilation operations for layer b (19).

[0112] The fresh air flow for ventilation operations in the A-layer mine 18 enters the intermediate transport roadway 11 from the auxiliary shaft, then enters the A-layer mine drilling roadway 5 through the external segment roadway 12 and the pedestrian ventilation shaft 15, finally entering the A-layer mine 18 mining area. After passing the working face, it enters the return air shaft through the return air roadway and is then discharged to the surface.

[0113] Ventilation operations in the 19th stope of the B-layer mine can be carried out by arranging local fans in the cross-vein roadway 1 of the A and B layers, sending fresh air into the stope via the following route: auxiliary shaft → intermediate transport roadway 11 → external segment roadway 12 → cross-vein roadway 1 of the A and B layers → cross-vein roadway 21 of the B-layer mine → 19th stope of the B-layer mine. After passing the working face, the stale air enters the filling return air shaft 10 in the opposite direction to the fresh air flow and is discharged to the surface from the north wing return air shaft.

[0114] The ore extraction operation is carried out after the blasting and ventilation of the ore body is completed. According to the quality grade of the ore body of layer a ore 18 and layer b ore 19, the ore extraction operation is divided into layer a ore 18 ore extraction operation and layer b ore 19 ore extraction operation.

[0115] The ore extraction operation of the a-layer ore 18 is carried out by transporting the ore directly to the a-layer ore pass 6 via the a-layer ore extraction access road 2 and the external segment roadway 12.

[0116] The ore extraction operation of the b-layer mine 19 is carried out by transporting the ore to the b-layer mine ore pass 7 via the b-layer mine vein roadway 21, the a- and b-layer mine vein-crossing roadways 1, and the external segment roadway 12.

[0117] When carrying out mining operations, attention should be paid to the safety of the area below the goaf, which can be judged by observing the frequency and size of the falling rocks from the roof.

[0118] If the ore extraction operation is damaged even after the roof support is in place, a metal mesh can be covered on the remote-controlled loader for protection. At the same time, personnel should be stationed outside the mining area to monitor the ore body that is prone to roof collapse, in order to prevent the loader from being damaged by the collapsing ore body.

[0119] The backfilling operation is carried out after the mining is completed, including the construction of the backfilling retaining wall 13, the backfilling operation in the mining area, and the dewatering operation of the backfilling slurry.

[0120] The filling retaining wall 13 operation is carried out at different locations in the a-layer mine 18 and the b-layer mine 19. The a-layer mine 18 is built at the ore exit entrance 2 of the a-layer mine, and the b-layer mine 19 is arranged in the vein roadway 21 of the b-layer mine.

[0121] The backfilling operation in the mining area is carried out in 3 to 4 stages to fill the goaf. The interval between each backfilling is the initial setting time of the backfill body, which is about 10 to 14 hours. The height of the first backfilling needs to be higher than the roof of the drilling and ore extraction roadway.

[0122] The backfilling operation in the mining area adopts a layered backfill body with high strength at the bottom and normal strength in the middle.

[0123] The filling slurry dewatering operation is carried out by pre-laying filter pipes in the mining area, and the filter pipes are not recycled later.

[0124] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0125] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0126] Through the above description of the embodiments, those skilled in the art can clearly understand that the above implementation methods can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0127] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method of mining a multi-ore zone fractured rock mass, the method comprising: Includes the following steps: S1. Determine the constituent elements of the ore block, including the panel size, ore block layout, stope layout, and pillar size; S2. Arrange the mining preparation works according to the constituent elements of the ore block. The mining preparation works are arranged in the footwall and vein of the ore body, wherein the mining preparation works of the ore layer near the footwall are arranged in the footwall of the ore body, and the mining preparation works of the ore body near the hanging wall are arranged in the vein. S3. After the mining preparation project is completed, the cutting and pulling work is carried out. The cutting and pulling work is carried out independently for different ore layers, and the upper section is constructed in advance of the lower section. S4. After the cutting and pulling of the bottom is completed, the pre-control operation of the mining area is carried out to support the roof of the mining area and to carry out differentiated support according to different mining sections and surrounding rock conditions. S5. After the pre-control roof operation is completed, the mining operation is carried out. The mining operation is carried out in the order of mining the lower ore body first and then mining the upper ore body. The mining and filling operation of the lower ore body is at least one segment ahead of the upper ore body. The mining operation includes rock drilling and blasting, stope ventilation, ore extraction and stope filling.

2. A method of mining a multi-ore zone fractured rock body according to claim 1, characterised in that, In step S1: The length of the panel is set to 100~120 m, the height is set to 50~80 m, and it is divided into 2~4 segments; Within the panel, each mineral layer is divided into 1 to 2 mineral blocks along its length. The length of each mineral block is determined by the length of the panel and the number of mineral blocks. Within the panel, several mining areas are divided along the length of each ore layer. The length of the mining area is equal to the thickness of the ore body, and the width is set according to the geological conditions of the ore and rock. One to two mining blocks of the same size are left between the panels as mining channels for the upper ore body.

3. A method of mining a multi-ore zone fractured rock body according to claim 1, characterised in that, Step S2 includes: External segmented roadways are arranged in the footwall surrounding rock, 10-20 m away from the footwall ore body, and connected by inclined ramps; In each stope, a separate rock drilling roadway perpendicular to the strike of the ore body is arranged in the footwall ore layer, which also serves as the mining roadway; Multiple vein tunnels are arranged within the column section of the panel. Each section is equipped with a vein tunnel, which is perpendicular to the strike of the ore body and has a length equal to the thickness of the ore body. Along the strike of the hanging wall ore body, a vein-connecting tunnel is arranged within the ore body on the side closest to the hanging wall. The length of the tunnel is the length of the hanging wall area, and it serves as both a drilling tunnel and an ore extraction tunnel. Cutting wells with a diameter of 2-4 m are arranged at the end of the mining area; Cutting tunnels are arranged within the ore body and connected to cutting risers to form an initial blasting free face with sufficient width and height; Arrange the lower and upper ore passes, with a horizontal distance of 10-15 m between them and a diameter of 3 m for each; Arrange connecting passages between the chute and the segmented roadways.

4. The method for mining multi-layered fractured rock mass according to claim 1, characterized in that, Step S3 includes: The lower ore layer is cut into the ore body through drilling roadways, the bottom of the upper sub-mining is opened and supported in time, and then the cutting riser is constructed. The upper ore layer is cut into the ore body through the vein roadway in the upper ore body, the bottom of the upper sub-mining is opened and supported in time, and then the cutting riser is excavated to connect with the pre-top layer. The bottom-laying operation was carried out entirely using smooth blasting excavation.

5. The method for mining multi-layered fractured rock mass according to claim 1, characterized in that, In step S4: The pre-controlled top support adopts a combination of anchor mesh and anchor bolts. The anchor bolt mesh is 2 m × 2 m in size, the anchor bolt diameter is 20 mm, and the length is 1.5~3 m. The anchor mesh is 2 m × 2 m in size and the diameter is 6~10 mm. Differentiated support methods are implemented based on different mining sections and surrounding rock conditions, including: for the first mining section, anchor bolt support is used, and for other sections, a combination of anchor mesh and anchor bolt support is used. For areas of the hanging wall ore layer near the hanging wall fracture zone, anchor cables are used for reinforcement. The anchor cables pass through the hanging wall fault zone for 3-4m and are arranged perpendicular to the hanging wall fracture surface.

6. The method for mining multi-layered fractured rock mass according to claim 1, characterized in that, Step S5 includes rock drilling and blasting operations: A medium-deep hole drilling rig was used to drill downward fan-shaped medium-deep holes. The spacing of the first row of blast holes near the cutting well is set to 0.5 to 0.7 times the minimum resistance line of normal rock drilling. Emulsion explosives are used, and the explosives are loaded mechanically using a loading trolley; At the time of detonation, a row of holes is blasted separately on the free face of the cutting well and the cutting level. Subsequently, 2 to 3 rows of blast holes are blasted each time, and digital detonators are used to carry out micro-delay blasting.

7. The method for mining multi-layered fractured rock mass according to claim 1, characterized in that, Step S5, the ventilation operation in the mining area, includes: Ventilation of the footwall: Fresh air enters the footwall from the auxiliary shaft through the intermediate transport roadway, the section roadway, and the rock drilling roadway, and then exits to the surface through the return air roadway and the return air shaft; Ventilation of the hanging wall: Local fans are installed in the pillar-crossing roadways between the hanging wall and the hanging wall. Fresh air flows through the auxiliary shaft, intermediate transport roadway, segment roadway, pillar-crossing roadway between the hanging wall and the hanging wall ore layer along the vein into the hanging wall. Stale air enters the return air shaft through the return air roadway and is discharged to the surface.

8. A method for mining multi-layered fractured rock mass according to claim 1, characterized in that, The ore extraction operation in step S5 includes: Ore extraction from the lower ore layer: Ore is transported from the lower ore layer extraction route to the lower ore layer pass via segmented roadways; Ore extraction from the hanging ore layer: Ore is transported from the hanging ore layer along the vein roadway, through the inter-plate pillar vein roadway and segmented roadway to the hanging ore layer pass; During the mining process, the frequency and size of falling rocks from the roof are used to assess safety.

9. A method for mining multi-layered fractured rock mass according to claim 1, characterized in that, Step S5, the stope backfilling operation, includes: Filling retaining walls were built at the ore inlet of the lower ore layer and in the vein roadway of the upper ore layer. The stope filling is carried out in 3 to 4 stages to fill the goaf. The interval between each filling is 10 to 14 hours after the initial setting time of the filling body. The height of the first filling is higher than the roof of the rock drilling and ore extraction roadway. The filling material adopts a layered filling method with high strength at the bottom and normal strength in the middle; The filling slurry is dewatered by pre-laying filter pipes in the mining area, and the filter pipes are not recycled.

10. A method for mining multi-layered fractured rock mass according to claim 1, characterized in that, In step S5, during the mining operation, the footwall ore body is mined backward from the side closest to the hanging wall ore body to the side closest to the footwall surrounding rock, and the hanging wall ore body is mined backward from the center of the panel to both sides.

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