A mining method of metal hard rock deposit with advanced pre-splitting assisted mechanical rock breaking

Abstract

The application discloses a kind of metal hard rock deposit advanced pre-splitting auxiliary mechanical rock breaking mining method;It is related to the technical field of ore mining;The method comprises the following steps: S1, layout of development engineering, including each roadway, chute and chamber;S2, rock mass pre-splitting;Pre-splitting borehole is used to apply cracking load to the inside of ore body, and pre-splitting ore body is formed;S3, ore recovery, using mobile rock breaking machinery for cutting and ore falling;S4, filling;S5, panel pillar recovery, after pre-splitting of the pillar, rock breaking machinery is used for cutting and ore falling recovery;The application uses the pre-splitting method to transform hard rock with f>6.0~8.0 into easy-to-cut ore body, the cutting specific energy consumption of mechanical rock breaking equipment is reduced by more than 30%, the single-tool cutting depth is increased by 50%~100%, and the tunneling speed is doubled.The wear rate of cutting tooth is slowed down, the consumption and replacement frequency are reduced by more than 60%, the cost of vulnerable parts and equipment downtime due to failure are significantly reduced.

Description

Technical Field

[0001] This invention relates to the field of ore mining technology, and in particular to a mining method for advanced pre-fracture assisted mechanical rock breaking in hard metal ore deposits. Background Technology

[0002] In deep, complex geological environments, rock masses exist under conditions of high ground stress, high ground temperature, and high osmotic pressure. Currently, traditional drill-and-blast methods remain the primary means of mining hard rock. However, under high-stress conditions at depth, blasting operations cause severe disturbance to the surrounding rock, easily inducing dynamic disasters such as rock bursts, roof falls, and spalling, seriously threatening the safety of underground personnel and equipment. Furthermore, drill-and-blast methods suffer from poor operational continuity and difficulty in intelligent upgrades, making it difficult to meet the development needs of green, safe, and efficient mining of deep resources.

[0003] In recent years, non-explosive mechanical rock breaking equipment, represented by cantilever tunneling machines and continuous mining machines, has been gradually applied to metal mines. Compared with traditional drill and blast methods, non-explosive mechanical rock breaking has significant advantages such as less excavation disturbance, more regular shaping, stronger operational continuity, and easier intelligent control, and is considered a key technical approach to achieving non-explosive continuous mining in deep hard rock mines. However, the ore bodies mined in deep hard rock mines are often characterized by high strength, high hardness, and strong abrasiveness (e.g., Protodyakonov hardness coefficient f > 6.0~8.0). When directly cutting such high-hardness ores, existing mechanical rock breaking equipment suffers from severe wear of cutting teeth, a sharp reduction in cutting tooth life, high frequency of cutting tooth replacement, and low tunneling efficiency. This leads to a sharp increase in the overall construction cost under such geological conditions, resulting in poor economic efficiency and severely restricting the large-scale promotion and application of non-explosive mechanical rock breaking technology in hard rock mines. Summary of the Invention

[0004] In order to improve the working conditions of mechanical rock breaking, reduce the difficulty of rock breaking, increase tool life and mining efficiency, this application provides a mining method for mechanical rock breaking assisted by pre-splitting in metal hard rock deposits.

[0005] This application provides a mining method for advanced pre-fracture assisted mechanical rock breaking in hard metal deposits, employing the following technical solution:

[0006] A mining method for advanced pre-fracture assisted mechanical rock breaking in hard metallic rock deposits includes the following steps:

[0007] S1. Layout of mining preparation works, including intermediate transport roadways, segment roadways, stope connecting roadways, ore passes, unloading chambers, pillars, pre-splitting roadway connecting roadways, pre-splitting roadways and vein roadways;

[0008] S2. Rock mass pre-splitting: Drill one or more rows of pre-splitting boreholes into the stope of the ore body in the pre-splitting roadway. Use the pre-splitting boreholes to apply fracturing load to the interior of the ore body, so that a fracture network is formed inside the ore body, thus forming a pre-splitting ore body.

[0009] S3. Ore mining: Mobile rock-breaking machinery is used to enter the mining passage through the mining connection roadway. The pre-fractured ore body is cut and the ore is extracted in the order of one-on-one or two-on-one mining. The extracted ore is transferred to the unloading chamber through the vein roadway, mining connection roadway and segment roadway, and then lowered to the intermediate transport level through the ore pass.

[0010] S4. Backfilling: After one approach is completed, an artificial false bottom is constructed at the bottom of the stope. A backfilling retaining wall is constructed between the goaf and the unmined approach. Backfilling slurry is transported to the goaf to form a backfill body. After curing to the design strength, the adjacent approaches are mined in sequence.

[0011] S5. Panel pillar mining: After all sections of this panel and adjacent panels have been mined and filled, pre-splitting holes are drilled into the panel pillars in the pre-splitting roadway and fracturing loads are applied. Rock breaking machinery is used to cut and remove ore from the pre-splitting panel pillars. After mining is completed, filling is carried out.

[0012] Optionally, step S1 includes the following:

[0013] Along the strike of the ore body, a middle section transport roadway is excavated in the footwall surrounding rock of the ore body as the main transport channel;

[0014] Based on the stage height, the ore body is divided into several segments along the vertical direction within the stage, and segment roadways are excavated horizontally in each segment.

[0015] From the segmented roadway, a connecting roadway is excavated towards the ore body to connect the mining face with each transport roadway;

[0016] In the lower footing of the mining area, a pass is excavated. The pass is connected to each section roadway by a connecting roadway, and the lower part of the pass is connected to the middle section transport roadway. The end of the connecting roadway is widened to form an unloading chamber.

[0017] Panel pillars are arranged at the junctions of each panel. Pre-splitting roadways are excavated from the segmented roadways to connect the ore body at the boundary or inside the design stope, and then the pre-splitting roadways are excavated parallel to the ore body mining face. The pre-splitting roadways are arranged in the middle of the panel pillars and are arranged adjacent to the ore body to be mined. They serve as dedicated chambers for the construction of pre-splitting boreholes. According to the needs of the working face for access mining, ventilation and auxiliary transportation, roadways along the vein are arranged at the edge of the ore body or in the surrounding rock.

[0018] Optionally, in step S2, the pre-splitting borehole extends from the pre-splitting roadway into the interior of the panel stope, and the borehole depth covers the entire width of the panel stope.

[0019] Optionally, the pre-splitting boreholes are drilled from the pre-splitting roadways on one or both sides of the panel into the stope of the panel; when drilling from both sides is used, the boreholes on both sides are arranged alternately.

[0020] Optionally, in step S2, the fracturing load is applied by one or more combinations of hydraulic fracturing pre-fracturing, explosive pre-fracturing, microwave pre-fracturing, static fracturing agent pre-fracturing, high-voltage electric pulse pre-fracturing, and mechanical grooving pre-fracturing.

[0021] Optionally, in step S2, if blasting pre-fracture is used, a decoupled charge structure is used, and a blocking section is reserved at the borehole opening; if hydraulic fracturing and blasting pre-fracture are combined to induce fracturing, hydraulic fracturing is performed first to expand and connect the original fractures, and then blasting pre-fracture is performed to form a through crack between the holes.

[0022] When performing pre-splitting of the ore body, pre-splitting should not be carried out in the area adjacent to the ore body and the panel pillar, or the pre-splitting load should be reduced to minimize the impact of the pre-splitting load on the panel pillar during the pre-splitting process of the ore body.

[0023] Optionally, in step S3, during the mining operation, fresh air flows through the segmented roadways, the mining area connecting roadways, and the roadways along the vein into the mining area passage; polluted air is discharged through the roadways along the vein, the mining area connecting roadways, and the segmented roadways.

[0024] Optionally, in step S3, the ore mining adopts a downward approach mining method, advancing layer by layer from the upper segment to the lower segment, and the rock-breaking machinery performs cutting operations under the protection of the artificial false bottom constructed by the upper layer of filling body.

[0025] Optionally, in step S5, before the panel pillar is mined, pre-splitting holes are drilled into the pillars on both sides in the pre-splitting roadway. The drilling depth extends through the width of the pillar to the contact boundary between the pillar and the filling body, and the fracturing method is the same as in step S2.

[0026] Optionally, the cross-section of the intermediate transport roadway and the segmented roadway is a straight arch shape, and the cross-section of the mining area connecting roadway, pre-splitting roadway, along-vein roadway and access roadway is rectangular.

[0027] In summary, this application includes the following beneficial technical effects:

[0028] 1. Significantly improved rock-breaking efficiency and equipment lifespan: Advanced pre-splitting transforms hard rock with a thickness (f) of 6.0–8.0 into easily cuttable ore bodies. The cutting energy consumption of mechanical rock-breaking equipment is reduced by more than 30%, the single-blade cutting depth is increased by 50%–100%, and the tunneling speed is doubled. The wear rate of cutting teeth is slowed, reducing consumption and replacement frequency by more than 60%, significantly decreasing the cost of wear parts and equipment downtime.

[0029] 2. Achieving safe, continuous, and non-explosive mining of deep hard rock deposits: This avoids the risks of rockbursts and spalling induced by traditional drill-and-blast methods in deep, high-stress areas. The mining process generates no blasting vibrations or toxic gases, improving the working environment. The downward-approach mining method ensures that rock-breaking machinery operates under artificial roof protection, resulting in excellent roof safety conditions. Only temporary support is needed for locally unstable areas, ensuring strong process continuity. Sequential mining with alternating sections between panels effectively prevents stress concentration and further reduces the risk of regional ground pressure disasters.

[0030] 3. Strong adaptability to the process and broad application prospects: This method has strong adaptability to changes in ore body morphology, and the pre-splitting process is flexible and diverse. It can be optimized and combined according to different mine geological conditions and production scales, and is especially suitable for deep hard rock mines using the backfilling mining method. Attached Figure Description

[0031] Figure 1 This is a front view of the mining method of the present invention;

[0032] Figure 2 This is a top view of the mining method of the present invention;

[0033] Figure 3 This is a side view of the mining method of the present invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1. Intermediate transport roadway; 2. Sectional roadway; 3. Stope connecting roadway; 4. Passage; 5. Unloading chamber; 6. Pre-splitting roadway connecting roadway; 7. Pre-splitting roadway; 8. Vein roadway; 9. Ore body; 10. Stope passage; 11. Pre-splitting borehole; 12. Pre-splitting ore body; 13. Rock breaking machinery; 14. Ore heap; 15. Backfill body; 16. Artificial false bottom; 17. Panel pillar. Detailed Implementation

[0036] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0037] This embodiment takes a certain hard rock metal mine as an example. Ore body 9 is a steeply dipping, medium-thick ore body with an average thickness of 15m and a dip angle of 70°. The Protodyakonov hardness coefficient of the ore is f=8.0~10.0, which is a typical high-hardness, difficult-to-mine body. The mining method of advanced pre-splitting assisted mechanical rock breaking for hard rock metal deposits described in this invention is used for mining. The specific implementation process is as follows.

[0038] S1, Preparation Engineering Layout

[0039] Along the strike of the ore body, a mid-section transport roadway 1 was excavated in the footwall surrounding rock. The roadway has a three-centered arch cross-section, with a net width of 4.5m and a net height of 4.0m, serving as the main transport channel. Based on the stage height of 60m, the stage was divided into four segments vertically, each segment height being 15m. Sub-segment roadways 2 were excavated horizontally in each segment, also with a three-centered arch cross-section, a net width of 4.0m and a net height of 3.8m.

[0040] From each section roadway 2, a connecting roadway 3 is excavated towards the ore body. It has a rectangular cross-section, a net width of 4.0m, and a net height of 3.7-3.8m, connecting the mining face with the main transportation network. A pass 4, with a diameter of 3.0m, is excavated in the footwall of the stope. Pass 4 connects to each section roadway 2 via connecting roads. The lower part of pass 4 connects to the intermediate transportation roadway 1. The ends of each connecting roadway are widened to form unloading chambers 5, used for collecting and sliding collapsed ore.

[0041] Along the strike of the ore body, six panels are divided at 60m intervals. Panels are mined in an alternating order, with panels one, three, and five being mined first. Panels two, four, and six are mined only after all odd-numbered panels have been mined and filled. This intermittent mining avoids stress concentration caused by simultaneous mining of adjacent panels, ensuring the stability of the regional rock mass.

[0042] To ensure safe mining in each panel, a 12.0m wide pillar 17 is reserved at the junction of two panels, meaning each panel boundary occupies a 6.0m pillar width. At the center of each panel pillar 17, a pre-splitting roadway connecting roadway 6 is excavated from the segment roadway 2, and then a pre-splitting roadway 7 is excavated parallel to the ore body mining face. The roadway has a rectangular cross-section, with a net width of 4.0m and a net height of 3.8m. The pre-splitting roadway 7 is located adjacent to the ore body to be mined and serves as a dedicated chamber for the construction of pre-splitting boreholes 11. Based on the needs of the working face for access mining, ventilation, and auxiliary transportation, a vein-side roadway 8 is arranged in the surrounding rock at the edge of the ore body. The roadway has a rectangular cross-section, with a net width of 3.5m and a net height of 3.7~3.8m, consistent with the access road height.

[0043] S2, Rock mass pre-splitting

[0044] Within the pre-splitting roadways 7 on both sides of the panel, drilling rigs are used to drill medium-deep holes 11 into the stope of the panel to be mined, with a hole diameter of 75mm. The pre-splitting holes 11 are arranged along the strike of the ore body, extending from the pre-splitting roadways 7 on both sides towards the central area of ​​the stope. The holes on both sides are staggered, with a drilling depth of 25m, covering the entire width of the stope. The spacing between holes is 1.2m, the row spacing is 1.0m, and the holes are parallel to the strike of the ore body.

[0045] Pre-splitting operations can employ one or more combinations of the following pre-splitting methods:

[0046] Hydraulic fracturing pre-fracturing: High-pressure water is injected into the borehole using a high-pressure water pump. Through the action of water wedges, the original fractures are expanded and connected to form an artificial fracture network.

[0047] Pre-splitting blasting: A small amount of explosive or special pre-splitting explosive cartridges are loaded into the borehole for decoupled blasting, and the explosive gas and stress wave are used to form a through crack between the holes.

[0048] Microwave pre-fracture: Selective and rapid heating of the surrounding rock and ore using a microwave generator, and thermal stress generated by the difference in thermal expansion of different minerals to induce intergranular cracks.

[0049] Static fracturing agent pre-fracturing: Static fracturing agent slurry is injected into the borehole, and the continuous volume expansion force generated by its hydration reaction slowly expands and fractures the ore body.

[0050] High-voltage electrical pulse pre-fracture: High-voltage pulse discharge is generated in the borehole through electrodes, and the shock wave formed by the electrohydraulic effect causes a network of micro-fractures inside the ore.

[0051] Mechanical grooving pre-splitting: Using a diamond wire saw or high-pressure abrasive water jet inside the borehole, guide grooves are cut along the design direction to induce and control the propagation of rock mass cracks.

[0052] In this embodiment, a combination of hydraulic fracturing and blasting pre-fracturing is used for fracturing. First, hydraulic fracturing is performed: high-pressure water is injected into each pre-fracturing borehole 11 using a high-pressure water pump at a pressure of 30-40 MPa. The water wedge effect expands and connects the original fractures around the borehole, forming a preliminary artificial fracture network. After hydraulic fracturing, blasting pre-fracturing is performed: 63mm diameter pre-fracturing explosive cartridges are loaded into the boreholes for decoupled blasting. The charge per meter per borehole is 3.3 kg / m, and the borehole plugging length is 6.0 m. A 2m area within the ore body is left uncharged, reducing disturbance to the panel pillars. The explosive gas and stress waves create through-cracks between the boreholes, further weakening the internal structure of the ore body. The staggered arrangement of boreholes on both sides ensures that fractures fully converge and connect in the center of the stope, forming a uniform fracture network.

[0053] After the pre-splitting operation is completed, the ore body inside the stope of the panel is sufficiently weakened, and the original fractures expand and connect, forming a pre-splitting ore body 12, whose Protodyakonov hardness coefficient is equivalently reduced to f=4.0~5.0. The panel pillar 17 is not pre-splitting, maintaining its integrity and support capacity.

[0054] S3, Ore Mining

[0055] After the pre-splitting operation is completed and safety is confirmed, a cantilever roadheader (13) is used as the rock-breaking machinery to enter the stope passage (10) via the stope connecting roadway (3). The mining operation proceeds in an alternating-cut sequence, meaning adjacent stope access roads are mined sequentially with an interval of one access road. The access road cross-section is rectangular, with a net width of 4.0m and a net height of 3.8m. Due to the use of downward access mining, the cantilever roadheader is always protected by the artificial false bottom (16) constructed by the upper segment backfill body (15) during cutting operations, resulting in good roof stability. During the tunneling process, only temporary anchor bolt support is required for locally jointed or fractured areas; full-face system support is not necessary, significantly reducing the time spent on support operations in mining operations and effectively improving mining efficiency.

[0056] Fresh air flows through segmented roadway 2, stope connecting roadway 3, and vein roadway 8 into stope passage 10, while polluted air is discharged through vein roadway 8, stope connecting roadway 3, and segmented roadway 2. The air volume at the working face is maintained above 4.0 m³ / s.

[0057] The cantilever roadheader advances perpendicular to the strike of the ore body, starting from one end of the stope, and uses a cutting head to cut and extract ore from the pre-fractured ore body 12. Because the ore body has been pre-fractured and weakened, the cutting head can easily penetrate, achieving a single-blade cutting depth of 0.3~0.4m, with a cutting speed approximately 50% higher than directly cutting primary hard rock. The extracted ore accumulates on the floor, forming a ore heap 14. When the cutting reaches the boundary of the ore body, the cutting operation on that route is stopped, the cantilever roadheader exits the existing route, and the machine continues operation on the next route to be mined, proceeding in an alternating order.

[0058] During the tunneling process, temporary support was provided in locally fractured areas using anchor bolts and metal mesh. The anchor bolts were 1.8m long to ensure the stability of the mining passage 10 and the safety of the operation.

[0059] A loader is used to transport the ore in the ore pile 14 through the stop passage 10, the vein roadway 8, the stop connecting roadway 3, and the segment roadway 2 to the unloading chamber 5 at the top of the ore pass 4. The ore is then unloaded into the ore pass 4 and lowered to the intermediate transport level. Finally, the ore is transported to the surface by ore cars in the intermediate transport roadway 1.

[0060] S4, Filling

[0061] After the ore is mined out of one route, a steel mesh is laid at the bottom of the stope and a 0.5m thick reinforced concrete is poured to construct an artificial false bottom 16, which serves as a stable roof for the next sub-section of mining.

[0062] A concrete retaining wall is poured between the goaf and the unmined access road. After the retaining wall has been cured for 3 days, full tailings paste filling slurry is transported to the goaf through filling pipelines. The filling slurry concentration is 72%~74% and the cement-sand ratio is 1:8~1:10.

[0063] After the backfill grout is injected, it undergoes curing for 28 days. Once the backfill body 15 has reached the design strength, mining operations on adjacent access routes are carried out in an alternating pattern. After all four access routes in this section have been mined and backfilled, and the backfill body 15 has reached its design strength, the process transitions to step S5 for the mining of pillar 17 in the panel. Only after all four sections of this panel have been mined and backfilled can the next layer be prepared for mining and mining operations.

[0064] S5, Panel Pillar Mining

[0065] After all sections of this panel and adjacent panels have been mined and filled, and the filling body 15 has reached the designed strength, the panel pillar 17 at the junction of the two panels is recovered under the support and protection of the filling body 15.

[0066] A pre-splitting roadway 7 has been installed in the middle of pillar 17 in the panel. Before mining, two rows of pre-splitting boreholes 11 were drilled into the pillars on both sides using a drilling rig in the pre-splitting roadway 7. The borehole diameter was 65mm, and the boreholes penetrated the width of the pillar to the contact boundary between the pillar and the backfill 15. Static fracturing agent pre-splitting was used: static fracturing agent slurry was injected into the boreholes, and the pillar was slowly fractured by the continuous volume expansion force generated by the hydration reaction. After standing for 6-8 hours, the internal fractures of the pillar were fully developed.

[0067] After the pre-splitting operation is completed and safety is confirmed, the tunneling machine enters the pre-splitting roadway 7 to cut and remove ore from the pre-splitting pillars 17 on both sides of the panel. The removed ore is piled on the bottom plate of the pre-splitting roadway 7 and transported by a loader through the pre-splitting roadway connecting roadway 6 and the segment roadway 2 to the unloading chamber 5 at the top of the ore pass 4. The ore is then unloaded into the ore pass 4 and lowered to the intermediate transport level for transport to the surface.

[0068] During the cutting process, temporary support was provided in locally broken areas using anchor bolts and metal mesh. The anchor bolts were 1.8m long to ensure the stability of the working space and the safety of personnel and equipment.

[0069] After the mining of pillar 17 in the panel was completed, filling retaining walls were poured at both ends of the goaf. The tailings paste filling slurry was transported through the filling pipeline for filling, with a lime-sand ratio of 1:8, forming filling body 15, which is connected with the existing filling bodies in the panels on both sides to jointly maintain the overall stability of the regional rock mass.

[0070] After pillar 17 in the panel was mined and filled, all mining operations in this panel were completed, and the operation shifted to the adjacent panel for preparation and mining.

[0071] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A mining method for advanced pre-fracture assisted mechanical rock breaking in hard metal rock deposits, characterized in that: Includes the following steps: S1. Layout of mining preparation works, including intermediate transport roadways, segment roadways, stope connecting roadways, ore passes, unloading chambers, panel pillars, pre-splitting roadway connecting roadways, pre-splitting roadways and vein roadways; Panel pillars are arranged at the junctions of each panel. Pre-splitting roadways are excavated from the segmented roadways to connect the ore body at the boundary or inside the ore body near the designed stope, and then the pre-splitting roadways are excavated parallel to the ore body mining face. The pre-splitting roadways are arranged in the middle of the panel pillars and are arranged adjacent to the ore body to be mined. They serve as dedicated chambers for the construction of pre-splitting boreholes. According to the needs of the working face for access mining, ventilation and auxiliary transportation, roadways along the vein are arranged at the edge of the ore body or in the surrounding rock. S2. Rock mass pre-splitting: Drill one or more rows of pre-splitting boreholes into the stope of the ore body in the pre-splitting roadway. Use the pre-splitting boreholes to apply fracturing load to the interior of the ore body, so that a fracture network is formed inside the ore body, thus forming a pre-splitting ore body. The pre-splitting borehole extends from the pre-splitting roadway into the interior of the stope panel, and the borehole depth covers the entire width of the stope panel. When pre-splitting the ore body, pre-splitting should not be carried out in the area adjacent to the ore body and the panel pillar, or the pre-splitting load should be reduced to minimize the impact of the pre-splitting load on the panel pillar during the ore body pre-splitting process. S3. Ore mining: Mobile rock-breaking machinery is used to enter the mining passage through the mining connection roadway. The pre-fractured ore body is cut and the ore is extracted in the order of one-on-one or two-on-one mining. The extracted ore is transferred to the unloading chamber through the vein roadway, mining connection roadway and segment roadway, and then lowered to the intermediate transport level through the ore pass. S4. Backfilling: After one approach is completed, an artificial false bottom is constructed at the bottom of the stope. A backfilling retaining wall is constructed between the goaf and the unmined approach. Backfilling slurry is transported to the goaf to form a backfill body. After curing to the design strength, the adjacent approaches are mined in sequence. S5. Panel pillar mining: After all sections of this panel and adjacent panels have been mined and filled, pre-splitting holes are drilled into the panel pillars in the pre-splitting roadway and fracturing loads are applied. Rock breaking machinery is used to cut and remove ore from the pre-splitting panel pillars. After mining is completed, filling is carried out.

2. The mining method for advanced pre-fracture assisted mechanical rock breaking in a hard metal rock deposit according to claim 1, characterized in that: Step S1 includes the following: Along the strike of the ore body, a middle section transport roadway is excavated in the footwall surrounding rock of the ore body as the main transport channel; Based on the stage height, the ore body is divided into several segments along the vertical direction within the stage, and segment roadways are excavated horizontally in each segment. From the segmented roadway, a connecting roadway is excavated towards the ore body to connect the mining face with each transport roadway; In the lower footing of the mining area, a pass is excavated. The pass is connected to each section roadway by a connecting roadway, and the lower part of the pass is connected to the middle section transport roadway. The end of the connecting roadway is widened to form an unloading chamber.

3. The mining method for advanced pre-fracture assisted mechanical rock breaking in a hard metal rock deposit according to claim 2, characterized in that: The pre-splitting boreholes are drilled from the pre-splitting roadways on one or both sides of the panel into the stope of the panel; when drilling from both sides is used, the boreholes on both sides are arranged alternately.

4. The mining method for advanced pre-fracture assisted mechanical rock breaking in a hard metal rock deposit according to claim 3, characterized in that: In step S2, the fracturing method is one or more combinations of hydraulic fracturing pre-fracturing, explosive pre-fracturing, microwave pre-fracturing, static fracturing agent pre-fracturing, high-voltage electric pulse pre-fracturing, and mechanical grooving pre-fracturing.

5. The mining method for advanced pre-fracture assisted mechanical rock breaking in a hard metal rock deposit according to claim 4, characterized in that: In step S2, if blasting pre-fracture is used, a decoupled charge structure is adopted, and a blocking section is reserved at the borehole opening; if hydraulic fracturing and blasting pre-fracture are combined to induce fracturing, hydraulic fracturing is performed first to expand and connect the original fractures, and then blasting pre-fracture is performed to form a through crack between the holes.

6. The mining method for advanced pre-fracture assisted mechanical rock breaking in a hard metal rock deposit according to claim 1, characterized in that: In step S3, during the mining operation, fresh air flows through the segmented roadways, the mining area connecting roadways, and the roadways along the vein into the mining area passage; polluted air is discharged through the roadways along the vein, the mining area connecting roadways, and the segmented roadways.

7. A mining method for advanced pre-fracture assisted mechanical rock breaking in a hard metal rock deposit according to claim 6, characterized in that: In step S3, the ore mining adopts a downward approach mining method, advancing layer by layer from the upper section to the lower section. The rock-breaking machinery performs cutting operations under the protection of the artificial false bottom constructed by the upper layer of filling body.

8. The mining method for advanced pre-fracture assisted mechanical rock breaking in a hard metal rock deposit according to claim 1, characterized in that: In step S5, before the panel pillar is mined, pre-splitting holes are drilled into the panel pillars on both sides in the pre-splitting roadway. The drilling depth extends through the width of the panel pillar to the contact boundary between the panel pillar and the filling body.

9. A mining method for advanced pre-fracture assisted mechanical rock breaking in a hard metal rock deposit according to claim 1, characterized in that: The cross-sections of the intermediate transport roadway and the segmented roadway are straight arches, while the cross-sections of the mining area connecting roadway, pre-splitting roadway, vein roadway, and access roadway are rectangular.

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