A hard rock mine drift mechanized ore draw continuous mining method

Abstract

This invention discloses a mechanized continuous mining method for hard rock mines, comprising the following steps: S1, setting ore block structure parameters; S2, layout of preparation and cutting engineering; S3, pre-fracture and lubrication of the ore body in the access road; S4, mechanized ore cutting, transportation, support and ventilation; S5, segmented backfilling of the access road. The mining units are divided into ore blocks, segments, layers, and access roads, with the mining sequence being forward-moving within the access road, intermittent access road within layers, and upward-moving layered access road within the ore block. The access road rock mass is pre-fractured using a hydraulic fracturing system, and the access road is then segmented and backfilled after mining. This invention overturns the traditional drilling and blasting process in hard rock deposits, realizing mechanized continuous parallel operation with a short process flow in hard rock ore bodies. It requires less personnel and equipment investment, and minimizes ore loss and dilution. It has advantages such as safety, efficiency, economy, and environmental protection. It has good adaptability to medium-thick or thick ore bodies with dips or elevations, and is an important guarantee for the intelligent construction of hard rock mines, with extremely broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of mining technology, and in particular to a mechanized continuous mining method for hard rock mine access routes. Background Technology

[0002] Mineral resources are the lifeblood of the national economy and an important material foundation for human survival. For a long time, the drilling and blasting method has been commonly used for mining hard rock mineral resources, including both metallic and non-metallic minerals. This method consists of multiple independent processes such as drilling, blasting, ventilation, slag removal, and support. The sequence of each step is strictly controlled, making parallel and continuous operation impossible in the same space. This results in long cycle times, dispersed personnel and equipment, low production efficiency, poor working conditions, high energy consumption, and high costs.

[0003] Furthermore, the drill-and-blast method in mining causes extensive damage to the surrounding rock due to strong disturbances, and is prone to inducing rock disasters such as roof falls, spalling, water inrush, and rock bursts, as well as safety accidents such as gas poisoning and explosions. Moreover, the difficulty in controlling the blasting boundary and the resulting over- and under-excavation phenomena lead to significant ore loss and dilution. Clearly, the drill-and-blast method is a major bottleneck restricting safe, efficient, and green mining, and also a significant factor limiting the development level of mine mechanization, automation, and intelligence. Therefore, it is imperative to transform the traditional drill-and-blast method and develop new short-process mining technologies or processes with efficient and coordinated operations. This will enable the use of highly adaptable and system-integrated equipment for mechanized continuous mining, providing crucial support and guarantees for implementing mechanized reduction of manpower, automation replacement of manpower, and intelligent unmanned operation.

[0004] Hard rock ore bodies have poor cutability, making direct mechanical rock breaking difficult. In recent years, companies such as Sany, XCMG, Shanxi Coal Machinery, and CRRC Equipment have developed cantilever roadheaders with increasingly higher cutting power and stronger mechanical rock-breaking capabilities. While these machines have successfully excavated tunnels in hard rock masses with a Protodyakonov coefficient of f = 8–10, they still suffer from drawbacks such as high cutter tooth consumption, high dust concentration, and high energy consumption. Existing equipment has significant limitations in cutting rocks with even higher hardness (f > 10). In response, the coal industry has attempted to introduce TBM (Tunnel Boring Machine) technology, used in tunnel construction, into rock tunnel excavation, and has applied it in over 100 coal mines with some success. However, TBM technology requires significant equipment investment, has poor adaptability to complex geological conditions such as water-rich areas, and is only suitable for long, horizontal or inclined tunnels with relatively small slope variations. Clearly, non-coal mines have numerous and short development and cutting roadways, and the roadway width varies greatly depending on the ore body's dip. Therefore, the TBM (Tunnel Boring Machine) technology in non-coal mines is only suitable for longer inclined shafts, adits, ramps, and sections with large turning radii. In response, domestic and international scholars and engineers have proposed various auxiliary rock-breaking methods to promote the development of mechanized mining processes, such as "blasting pre-splitting + machine excavation," "blasting slotting + machine excavation," and "dense drilling + machine excavation." However, these improved processes still cannot avoid blasting and dense drilling operations, thus offering limited improvement in production efficiency.

[0005] Currently, the approach method is widely used in the mining of various ore bodies, and it has shown strong adaptability to the occurrence of ore bodies with various dip angles and thicknesses. Therefore, it is urgent to develop a mechanized continuous ore-cutting mining method that combines the traditional drill and blast method with the approach method to achieve safe, efficient and green mining of hard rock mines. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a mechanized continuous mining method for hard rock mine access routes.

[0007] This invention provides a mechanized continuous mining method for hard rock mines. First, the ore block is divided along the strike into stops and pillars. Within the stops, vertical segments are established, and within each segment, multiple layers are defined. Each layer is further divided into several access routes arranged along the strike. Second, a series of mining and cutting works, including stage transport and return airways, crosscuts, ore passes, and ramps, constitute a ventilation, transport, personnel, and backfilling system. Then, a hydraulic fracturing system is used to perform segmented pre-fracture and rock mass enrichment on the access ore body. Based on the forward-moving sequence within the access route, the intermittent access sequence within each layer, and the upward-moving sequence within the ore block, a roadheader is used for mechanical cutting and ore extraction and coordinated support of the fracturing rock mass. A scraper conveyor transports the ore to the ore pass, and ventilation is provided using an extraction method. Finally, after the access route is mined, a backfill retaining wall is poured for segmented backfilling.

[0008] The solution of the present invention is:

[0009] A mechanized continuous ore extraction method for hard rock mines includes the following steps:

[0010] S1. Setting of ore block structure parameters

[0011] The ore body is divided into several blocks along the strike. Each block is divided into a stope and a pillar, without top or bottom pillars. The stope is 200-250m long, the width is the thickness of the ore body, and the height is the stage height, which is 40-90m. The pillar is 4-10m wide, the length is the thickness of the ore body, and the height is the same as the stage height. The stope is evenly divided into 3-8 segments in the vertical direction. Each segment is evenly divided into 3-5 layers in the vertical direction. Each layer contains several access routes arranged along the strike as mining units.

[0012] S2, Preparation and Cutting Engineering Layout

[0013] Stage transport roadways, segment transport roadways, and stage return air roadways are set up along the strike of the footwall of the ore body. Each segment transport roadway is connected to the two stage roadways by ramps and chutes. Each segment has a cross-cutting vein arranged along the dip of the ore body, with one end crossing the segment and stage transport roadway to the boundary of the footwall of the ore body and the other end connecting to the chutes and ramps. This forms the ore extraction, material transportation, pedestrian and ventilation, and filling system. At the same time, the cross-cutting vein located in the center of the ore block forms a cutting space and free face in the ore body. As the upward layered mining continues, the bottom is continuously laid and the top is lifted to keep the production system unobstructed.

[0014] S3, Pre-fracture and wetting of the orebody at the entry point

[0015] Before mining the ore body, a horizontal or near-horizontal fracturing borehole with a diameter of 60-90 mm is drilled in the center of the ore body with a geological drilling rig at a cycle distance of 10-50 m. One to three observation holes with the same diameter and depth are drilled around the ore body. A hydraulic fracturing system is used to perform segmented pre-fracturing and rock wetting of the ore body. Fracturing is stopped when water comes out of the observation holes and the pressure drops sharply.

[0016] S4, Mechanized ore extraction, transportation and support, and ventilation.

[0017] Mining is carried out sequentially in three ways: forward mining within the access road, intermittent mining within the layers, and upward mining from the bottom to the top within the ore block. Within the access road, a roadheader is used to mechanically cut and continuously cut the pre-fracturing ore body. The ore is unloaded from the tail of the roadheader onto a retractable scraper conveyor embedded in the access road floor, and then transferred to the pass via a scraper conveyor laid in the center of the cross-section floor. The ore discharged from the pass is unloaded onto the conveying equipment in the stage transport roadway and transported to the bottom yard for hoisting to the surface. The roadheader can simultaneously perform anchor and mesh support operations on the surrounding rock of the access roadway. The scraper conveyor can be extended to move forward in close following the roadheader. Ventilation is extracted to the stage return airway through ventilation ducts arranged in the access roadway, cross-section, and inclined roadway.

[0018] S5, subsequent filling of the approach segment

[0019] After one approach is mined, the mining equipment is withdrawn, and the approach is filled in sections according to the cycle distance by constructing a filling retaining wall to ensure that the filling body fully contacts the top. The bottom layer filling is constructed by laying steel bars and pouring concrete to form a false bottom, and the remaining layers are filled with cemented sand. The mining equipment withdrawn after the approach is mined is transported to the replacement approach, and then steps S1 to S5 are repeated for mechanized continuous mining followed by filling. Mining of 1 to 3 approaches is carried out simultaneously in the ore block.

[0020] As a preferred technical solution, the ore body is a medium-thickness or thicker ore body with a gently dipping to steeply dipping orientation.

[0021] As a preferred technical solution, the conveying equipment in S4 is a belt conveyor or a series of mining cars.

[0022] As a preferred technical solution, the access section is rectangular, with a width of 4-8m and a height of 3-6m, which is the layer height.

[0023] As a preferred technical solution, the cross-sectional shape of the stage roadway, segmented transport roadway, through roadway, and inclined roadway is one of the following: a three-centered arch, a straight-wall arch, a rectangle, or a trapezoid, with a cross-sectional area of ​​not less than 12m². 2 It must meet transportation and ventilation requirements. The cross-sectional diameter of the chute must be no less than 1.0m.

[0024] As a preferred technical solution, the hydraulic fracturing system includes a hydraulic geological drilling rig, fracturing drill rods, plugging devices, high-pressure hoses, a high-pressure water pump, and U-shaped clamp components. The hydraulic geological drilling rig is positioned near the approach face. The high-pressure water pump is connected to the hydraulic geological drilling rig and the water supply pipes of the approach roadway via high-pressure hoses with a diameter of 30-60mm and U-shaped clamps for fixing, respectively. The fracturing drill rods mounted on the hydraulic geological drilling rig have a hollow structure, with each section being 1.0-1.5m long. They can be freely lengthened or shortened using the hydraulic geological drilling rig via threaded connections. During fracturing, according to the design scheme, the fracturing drill rod with the drill bit at the front end is first connected to the hydraulic geological drilling rig to drill a fracturing borehole of a certain depth. Then, the drill bit is removed, and a plugging device is installed on the head of the fracturing drill rod. The plugging devices appear in pairs, with a thin metal tube of a certain length between the two plugging devices. One to three nozzles are radially opened in the middle of the metal tube. During hydraulic fracturing, the fracturing drill rod, equipped with a plug at its head, is first placed at the designated depth in the pre-drilled fracturing borehole using a hydraulic geological drilling rig. Then, the valve on the water supply pipe in the access roadway is opened, and water from the supply pipe is transported via a high-pressure hose to a high-pressure water pump for storage and pressurization. The output high-pressure water is then transported via a high-pressure hose through the hydraulic geological drilling rig to the fracturing drill rod. The high-pressure water flowing through the plug causes it to expand, sealing the fracturing section both before and after the borehole. High-pressure water ejected from the nozzle in the middle of the plug continuously pressurizes within the fracturing section. When the pressure reaches the tensile strength of the rock mass, rupture occurs, and the fracture spreads radially into the rock mass, ultimately forming a hydraulic fracture network. Hydraulic pre-fracturing not only increases the development of joints and fractures in the rock mass but also improves the wettability of the rock, enabling mechanized continuous cutting of hard rock ore bodies and reducing dust concentration.

[0025] As a preferred technical solution, the segmented fracturing within the fracturing borehole can be either an advancing or retreating type. For medium-hard rock conditions, the segmented fracturing within the fracturing borehole is an advancing type; for intact hard rock conditions, the segmented fracturing within the fracturing borehole is a retreating type. The segmented fracturing distance is 0.5–2.0 m, and double-sealing fracturing is implemented using two plugs. The plugs are 0.5–1.5 m long, 60–95 mm in diameter, and spaced 0.2–0.6 m apart.

[0026] As a preferred technical solution, the rated pressure of the high-pressure water pump is ≥50MPa, and the flow rate of the high-pressure water pump is ≥100m³ / h. 3 / min; Fracturing drill pipe and high-pressure hose with a pressure resistance of ≥70MPa.

[0027] As a preferred technical solution, the scraper conveyor has a conveying distance of ≥120m and a width of 0.4~0.6m; the tunneling and anchoring machine is equipped with 2~5 sets of hydraulic rock drilling mechanisms with functions such as rock drilling, charging, netting and anchor installation.

[0028] As a preferred technical solution, the anchor is one or more of an anchor rod or an anchor cable; the anchor rod is a resin anchor rod with a diameter of 18-25 mm and a length of 2.0-3.0 m; the anchor cable is a steel strand with a diameter of 15-25 mm and a length of 3.0-7.5 m; and the mesh is one of a metal mesh and a plastic mesh.

[0029] As a preferred technical solution, the filling retaining wall and the concrete false bottom are poured with C20 grade or higher concrete, and the ash-sand ratio of the tailings cemented filling slurry is ≥1:8 and the mass concentration is ≥68%.

[0030] A mechanized continuous mining method for hard rock mines, employing the aforementioned technical solution, includes the following steps: S1. Setting ore block structure parameters: Dividing the ore body along the strike into several ore blocks, each block consisting of a stope and a pillar, without top or bottom pillars; the stope is 200-250m long, its width equal to the ore body thickness, and its height equal to the stage height, which is 40-90m; the pillar is 4-10m wide, its length equal to the ore body thickness, and its height consistent with the stage height; the stope is vertically divided into 3-8 segments, each segment into 3-5 layers, and each layer contains several passes arranged along the strike as mining units; S2. Arranging preparation and cutting works: Setting up staged transport along the strike in the footwall of the ore body. The roadways, segmented transport roadways, and stage return air roadways are connected to the two-stage roadways via ramps and chutes. Each segment has a cross-cutting vein along the dip of the ore body, with one end crossing the segmented / stage transport roadway to the upper boundary of the ore body and the other end connecting to the chutes and ramps. This forms the ore extraction, material transport, personnel and ventilation, and backfilling system. Simultaneously, the cross-cutting vein located in the center of the ore block creates cutting space and free faces within the ore body, and as the upward layered mining progresses, it continuously lays the bottom and lifts the top to maintain the smooth operation of the production system. S3, the pre-fracking and lubrication of the approach ore body: Before mining the approach ore body, a horizontal or near-horizontal fracturing borehole with a diameter of 60-90 mm is drilled in the center of the approach section using a geological drilling rig at a circulation distance of 10-50 m. Drill 1-3 observation holes of the same diameter and depth around the perimeter. Use a hydraulic fracturing system to perform segmented pre-fracturing and rock wetting on the ore body of the access road. Stop fracturing when water appears in the observation holes and the pressure drops sharply. S4. Mechanized ore cutting, transportation, support, and ventilation. Mining is carried out in the following order: advancing within the access road, intermittent within the access road, and upward layering within the ore block. Within the access road, a roadheader is used to mechanically cut and continuously cut the pre-fractured ore body. The ore is unloaded from the tail of the roadheader onto a retractable scraper conveyor embedded in the access road floor, and then transferred to the pass via a scraper conveyor laid in the center of the cross-section floor. The ore discharged from the pass is unloaded onto the conveying equipment in the stage transport roadway and transported to the bottom yard for hoisting to the surface. The machine can simultaneously perform anchor and mesh support operations on the surrounding rock of the access road. The scraper conveyor can be extended to keep up with the forward movement of the tunneling and anchoring machine. Ventilation is drawn out to the stage return airway through the ventilation ducts arranged in the access road, through vein and ramp. S5, access road segmented backfilling: After one access road is mined, the mining equipment is withdrawn, and the access road is segmented and backfilled in sequence according to the cycle distance to ensure that the backfill body fully contacts the roof. The bottom layer backfilling adopts the method of laying steel bars and pouring concrete to construct a false bottom, and the other layers are backfilled with cemented sand. The mining equipment withdrawn after the access road is mined is transported to the replacement access road, and then steps S1 to S5 are repeated for mechanized continuous mining followed by backfilling. Mining of 1 to 3 access roads is carried out simultaneously in the stope.

[0031] Advantages of this invention:

[0032] (1) Hydraulic fracturing is used to pre-fracture hard ore bodies, turning the intact hard rock mass into a fractured rock mass, reducing the rock mass strength and increasing the rock mass cutability; at the same time, the water wedge and lubrication effect in the fracturing increases the water content and wettability of the rock mass, making mechanized ore cutting possible, and reducing the dust concentration in the stope during mechanical cutting ore cutting.

[0033] (2) In this method, mechanical ore cutting, continuous transportation, and coordinated support are carried out simultaneously in the same space. This not only overturns the traditional multi-stage ore cutting process of drilling and blasting, but also realizes a short-process parallel continuous operation of ore cutting, transportation, and support. This method is conducive to realizing mechanized and intelligent continuous mining in hard rock mines, with large mining production capacity, high work efficiency, small mining disturbance, low loss and dilution, and is economical, safe, and has a better working environment and intensity.

[0034] (3) The use of a small-width scraper conveyor to match the tunneling machine enables continuous ore transportation, improves ore extraction efficiency, and the scraper conveyor embedded in the bottom plate is simple to operate, does not affect material transportation or pedestrians, is flexible in extension and retraction, and is highly adaptable to ore extraction in medium and short distance strip or access mining areas.

[0035] (4) The pre-splitting and mining of the inner-layer approach reduces the pre-mining preparation time and is conducive to the smooth replacement of the mining; the subsequent segmented filling method in the approach can effectively improve the filling and roof connection rate. Attached Figure Description

[0036] Figure 1 This is a front view of the mining method according to Embodiment 1 of the present invention;

[0037] Figure 2 This is a cross-sectional view of the mining method in Embodiment 1 of the present invention;

[0038] Figure 3 This is a top view of the mining method according to Embodiment 1 of the present invention;

[0039] Figure 4 This is a schematic diagram of the hydraulic fracturing system structure in Embodiment 1 of the present invention.

[0040] Among them: 1-stope; 2-pillar; 3-sloping ramp; 4-pass chute; 5-stage haulage roadway; 6-stage return airway; 7-segment haulage roadway; 8-through vein; 9-concrete false bottom; 10-filling body; 11-access roadway; 12-fracturing borehole; 13-hydraulic fracture; 14-roadheader; 15-scraper conveyor; 16-hydraulic fracturing system; 161-high pressure water pump; 162-geological drilling rig; 163-fracturing drill rod; 164-sealing device; 165-high pressure hose; 166-U-shaped clamp; 17-filling retaining wall. Detailed Implementation

[0041] This invention provides a mechanized continuous mining method for ore extraction in hard rock mines.

[0042] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific embodiments.

[0043] Example 1:

[0044] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, firstly, the moderately thick to steeply dipping ore body is divided into several blocks along the strike. Each block is divided into a stope 1 and a pillar 2, without top or bottom pillars. The stope 1 is 200–250 m long, its width is the thickness of the ore body, and its height is the stage height (40–90 m). The pillar 2 is 4–10 m wide, its length is the thickness of the ore body, and its height is the same as the stage height. The stope 1 is evenly divided into 3–8 segments in the vertical direction. Each segment is evenly divided into 3–5 layers in the vertical direction, with a layer height of 3–6 m. Each layer is further subdivided into several access routes 11 arranged along the strike as mining units. The access route cross-section is rectangular, with a width of 4–8 m and a height equal to the layer height.

[0045] Secondly, stage transport roadways 5, segmented transport roadways 7, and stage return air roadways 6 are set up along the strike of the footwall of the ore body. Each segmented transport roadway 7 is connected to the two stage roadways through ramps 3 and chutes 4. Each segment is arranged with a crossbeam 8 along the dip of the ore body, which crosses the segmented / stage transport roadway at one end to reach the boundary of the footwall of the ore body, and connects to the chutes 4 and ramps 3 at the other end, forming a system for ore extraction, material transportation, pedestrian access, ventilation, and filling. At the same time, the crossbeam 8 located in the center of the ore block forms a cutting space and free face in the ore body, and the production system is kept unobstructed as the upward layered mining is carried out.

[0046] Secondly, before mining the ore body in access route 11, a horizontal or near-horizontal fracturing borehole 12 with a diameter of 60-90 mm is drilled in the center of the access route 11 section using a geological drilling rig 162 at a circulation distance of 10-50 m. At a certain distance around the fracturing borehole 12 on the access route 11 section, 1-3 observation holes with the same diameter and depth are drilled. The hydraulic fracturing system 16 is used to perform segmented pre-fracturing and rock mass lubrication on the ore body in access route 11. Fracturing is stopped when water comes out of the observation holes and the pressure drops sharply.

[0047] Then, mining proceeds sequentially according to the following methods: advancing within approach 11, intermittent approach within layers, and upward approach within the ore block from lower layers / sections to upper layers / sections. Within approach 11, a roadheader 14 mechanically cuts the pre-fracturing ore body for continuous ore extraction. Ore is unloaded from the tail of the roadheader 14 onto a retractable scraper conveyor 15 embedded in the floor of approach 11, and then transferred to the ore pass 4 via a scraper conveyor 15 laid in the center of the floor of the cross-section 8. Ore discharged from the ore pass 4 is unloaded onto the belt conveyor or tandem mine cars in the stage transport roadway 5 and transported to the bottom yard for hoisting to the surface. The roadheader 14 can simultaneously perform anchor bolt (cable) mesh support operations on the surrounding rock of approach 11. The scraper conveyor 15 can be extended to move forward closely following the roadheader 14. Ventilation from the stope is extracted to the stage return air roadway 6 through ventilation ducts arranged within approach 11, cross-section 8, and inclined ramp 3.

[0048] Finally, after one access route 11 is mined, the mining equipment is withdrawn, and a backfill retaining wall 17 is constructed according to the cycle distance. Then, the access route 11 is filled in sections using the backfill system to ensure that the backfill body 10 fully contacts the roof. The bottom layer backfill uses reinforced concrete to construct a false bottom 9, and the remaining layers are filled with cemented sand. The principle of pre-splitting before mechanical cutting is strictly followed within access route 11. After the entire access route 11 is mined, the withdrawn mining equipment is transported to the replacement access route, and steps S1 to S5 are repeated for mechanized continuous mining and subsequent backfilling. Mining of 1 to 3 access routes 1 can be carried out simultaneously within the stope.

[0049] The cross-sectional shape of the stage roadway 5, stage return airway 6, segmented transport roadway 7, through roadway 8, and inclined roadway is one of the following: a three-centered arch, a straight-wall arch, a rectangle, or a trapezoid, with a cross-sectional area of ​​not less than 12m². 2 The chute must meet the needs of transportation, ventilation, and pedestrians. The diameter of the chute section 4 shall not be less than 1.0m.

[0050] The fracturing system includes a hydraulic geological drilling rig 162, fracturing drill rods 163, a plugging device 164, a high-pressure hose 165, a high-pressure water pump 161, and a U-shaped clamp 166. Water from the roadway sidewall water supply pipe is transported to the high-pressure water pump 161 via a high-pressure hose 165 with a diameter of 30-60mm connected to the U-shaped clamp 166 for pressurization and storage. The water is then connected to the hydraulic geological drilling rig 162 via the hose 165. The high-pressure water is transmitted to the plugging device 164 through fracturing drill rods 163, which are spirally connected in sections of 1.0-1.5m, for pressure fracturing. Ultimately, hydraulic fractures 13 perpendicular to the minimum principal stress will appear in the rock mass surrounding the fracturing borehole 12 and form a network, thereby increasing the degree of fracturing and the cutability of the rock mass. The fracturing sequence within borehole 12 is divided into an advancing type (for medium-hard rock) or a retreating type (for intact, relatively hard rock) based on the rock mass hardness. The fracturing distance between segments is 0.5–2.0 m, and double-sealing fracturing is implemented using two plugs 164. The plugs 164 are 0.5–1.5 m long, 60–95 mm in diameter, and spaced 0.2–0.6 m apart. The high-pressure water pump 161 has a rated pressure of not less than 50 MPa and a flow rate of 100 m³ / h. 3 / min or higher; fracturing drill pipe 163 and high-pressure hose 165 withstand pressure of 70MPa or higher.

[0051] The roadheader 14 can simultaneously perform anchor bolt (cable) mesh support operations on the surrounding rock of the approach 11. It carries 2-5 sets of hydraulic rock-drilling mechanisms with functions such as rock drilling, charging, mesh installation, and anchor bolt installation. The anchor bolts are resin anchor bolts with a diameter of 18-25mm and a length of 2.0-3.0m, and the anchor cables are steel strands with a diameter of 15-25mm and a length of 3.0-7.5m. The scraper conveyor 15 can be extended to closely follow the roadheader 14, with a transport distance of not less than 120m and a width of 0.4-0.6m. Ventilation is extracted through ventilation ducts arranged within the approach 11, the through-passage 8, and the ramp 3 to the stage return airway 6.

[0052] The filling retaining wall 17 and the concrete false bottom 9 are made of C20 grade or higher concrete, and the ash-sand ratio of the tailings cemented filling slurry is ≥1:8 and the mass concentration is ≥68%.

[0053] The steps of the present invention are described below with reference to an embodiment:

[0054] The ore body in a certain mine has a depth of 500-1000m, a dip angle of 55°, and a thickness of 10m. The ore and rock are all granite with a Protodyakonov coefficient of 10-12. Joints and fissures are not well-developed, and the ore body and the hanging wall and footwall strata are relatively stable. Previously, the mine used the upward horizontal layered backfilling method, resulting in low stope production capacity (200t / d). Blasting operations resulted in high dust concentrations, long ventilation times, high labor intensity for workers, and a harsh working environment. Furthermore, the traditional drill-and-blast method is cumbersome, with complex procedures for drilling, charging and blasting, ventilation, ore extraction, and support that cannot be performed in parallel. This leads to dispersed personnel and equipment, resulting in a high risk of safety accidents. Precise control of blasting boundaries is difficult, leading to severe over- and under-excavation of the surrounding rock and significant ore loss and dilution. Therefore, to achieve safe, efficient, and green production in the mine, this method is adopted to transform the existing mining methods. The implementation steps are as follows:

[0055] (S1) Block structure parameter settings: The steeply dipping, medium-thick ore body is divided into several blocks along the strike. The blocks are divided into stopes 1 and pillars 2, without top or bottom pillars. Stope 1 is 245m long, the width is the thickness of the ore body, and the height is the stage height of 48m. Pillar 2 is 5m wide, the length is the thickness of the ore body, and the height is the same as the stage height. The stopes are evenly divided into 4 segments in the vertical direction. Each segment is evenly divided into 2-3 layers in the vertical direction, with a layer height of 4m. Each layer is further subdivided into 6 access routes 11 arranged along the strike as mining units. The cross-section of access route 11 is rectangular, with a width of 5m and a height of 4m.

[0056] (S2) Layout of Mining and Cutting Engineering: Stage haulage roadways 5, segmented haulage roadways 7, and stage return airway 6 are constructed along the strike of the footwall of the ore body. Each segmented haulage roadway 7 and the two stage roadways are connected by ramps 3 and chutes 4. For each segment, a cross-cutting vein 8 is arranged along the dip of the ore body, with one end crossing the segmented / stage haulage roadway to the edge of the footwall and the other end connecting to chutes 4 and ramps 3, forming a system for ore extraction, material transportation, pedestrian access, ventilation, and backfilling. Simultaneously, the cross-cutting vein 8, located in the center of the ore block, creates cutting space and a free face within the ore body, and the production system remains unobstructed as the upward layered mining progresses, with continuous bottoming and top lifting. The cross-sectional shape of stage roadways 5 and 6, segmented haulage roadway 7, cross-cutting vein 8, and ramps is a three-centered arch shape, with a net width of 4.5m, a wall height of 2.5m, and an arch height of 1.5m. Chute 4 has a cross-sectional diameter of 2.0m.

[0057] (S3) Pre-fracking and lubrication of the ore body in the approach: Before mining the ore body in approach 11, an XTDL-4 hydraulic geological drilling rig 162 is used to drill a horizontal or near-horizontal fracturing borehole 12 with a diameter of 65mm in the center of the approach 11 section at a circulation distance of 30m. Two observation holes of the same diameter and depth are drilled around approach 11. A hydraulic fracturing system 16 is used to perform segmented pre-fracking and lubrication of the ore body in approach 11. Fracturing is stopped when water appears in the observation holes and the pressure drops sharply. The fracturing system includes a hydraulic geological drilling rig 162, fracturing drill rod 163, plugging device 164, high-pressure hose 165, high-pressure water pump 161, and U-shaped clamp 166. Water from the roadway's sidewall water supply pipe is transported via a 60mm diameter high-pressure hose 165 connected by a U-shaped clamp 166 to a BZW200 / 31.5 high-pressure water pump 161 for pressurization and storage. The water is then connected via hose 165 to a hydraulic geological drilling rig 162. The high-pressure water is transmitted through 1.0m spirally connected fracturing drill rods 163 to two ZF-A60 plugs 164 installed at the head for pressure fracturing. This results in hydraulic fractures 13 perpendicular to the minimum principal stress forming a network around the fracturing borehole 12, increasing the fracture depth and cutability of the rock mass. The fracturing sequence within the fracturing borehole 12 uses a retreating fracturing method, with a fracturing distance of 1.0m between segments. Two plugs 164 are used for double-sealing fracturing; each plug is 1.5m long, 60mm in diameter, and spaced 0.3m apart. The high-pressure water pump 161 has a rated pressure of no less than 50MPa and a flow rate of 200m³ / h. 3 / min; Fracturing drill pipe 163 and high-pressure hose 165 withstand pressure of 70MPa.

[0058] (S4) Mechanized ore cutting, transportation, support and ventilation: The ore is mined in the following order: advancing type in the access road 11, intermittent type in the access road within the layer, and upward type in the layer within the block. In the access road 11, the EBZ260M roadheader 14 is used to mechanically cut the pre-fracturing ore body for continuous ore cutting. The ore is unloaded from the tail of the roadheader 14 onto a 0.4m wide retractable scraper conveyor 15 (model SGB620 / 40T) embedded in the center of the bottom plate of the access road 11. Then, it is transferred to the pass 4 by the scraper conveyor 15 laid in the center of the bottom plate of the cross vein 8. The ore released from the pass 4 is unloaded onto the belt conveyor or tandem mine cars in the stage transport roadway 5 and transported to the bottom yard for hoisting to the surface. The roadheader 14 can simultaneously perform anchor bolt (cable) mesh support operations on the surrounding rock of approach 11. The anchor bolts are 20mm in diameter and 2.2m in length resin anchor bolts, the anchor cables are 15-25mm in diameter and 3.0-7.5m in length steel strands, and the mesh is a Φ6mm metal mesh with dimensions of 2.24m × 1.22m and a grid size of 150 × 150mm. The ventilation from the stope is drawn out to the stage return airway 6 through ventilation ducts arranged in approach 11, cross-cut 8, and inclined ramp 3.

[0059] (S5) Subsequent backfilling of segmented access routes: After one access route 11 is mined out, the mining equipment is removed, and a backfilling system using tailings cemented (ash-sand ratio 1:6, mass concentration 72%) is used to construct backfilling retaining walls 17 at 30m circulation intervals to backfill access route 11 in segments, ensuring that the backfill body 10 fully contacts the roof. The bottom layer backfilling uses reinforced concrete C30 grade concrete to construct a false bottom 9, and the remaining layers are backfilled with cemented tailings. Within access route 11, the principle of pre-splitting before mechanical cutting is strictly followed. After the entire access route 11 is mined out, the removed mining equipment is transported to the replacement access route, and steps S1 to S5 are repeated for mechanized continuous mining and subsequent backfilling. Two access routes 1 can be mined simultaneously within the stope, with a daily production capacity of 1000t / d and ore loss and dilution of less than 5%.

[0060] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for continuous mining of hard rock mines, characterized in that, The method comprises the following steps: S1, setting structure parameters of ore blocks The ore body is divided into ore blocks along the strike, the ore blocks are divided into ore rooms and inter-columns without top and bottom pillars; the length of the ore room is 200-250 m, the width is the thickness of the ore body, and the height is the stage height, which is 40-90 m; the width of the inter-column is 4-10 m, the length is the thickness of the ore body, and the height is the same as the stage height; the ore room is evenly provided with 3-8 subsections in the vertical direction, each subsection is evenly provided with 3-5 sub-layers in the vertical direction, and a plurality of entries arranged along the strike are arranged in each sub-layer as a stoping unit; S2, layout of mining and cutting engineering A stage transportation roadway, a subsection transportation roadway and a stage air return roadway are arranged along the strike at the lower wall of the ore body, each subsection transportation roadway is connected with two stage roadways through a slope and a chute, each subsection is arranged along the inclination of the ore body to form a through vein connected with the chute and the slope at one end and reaching the boundary of the upper wall of the ore body at the other end, thereby forming a mining, material transportation, pedestrian and ventilation and filling system; meanwhile, the through vein located in the center of the ore block forms a cutting space and a free surface in the ore body, and the production system is kept unblocked by continuously paving the bottom and picking the roof during upward sub-layer mining; S3, advanced pre-cracking and moisture increase of the ore body in the entry Before mining the ore body in the entry, a geological drilling machine is used to drill a horizontal or near-horizontal fracturing borehole with a diameter of 60-90 mm in the center of the entry section at a cycle distance of 10-50 m, 1-3 observation holes with the same diameter and depth are drilled around the entry, a segmented advanced pre-cracking and rock mass moisture increase are performed on the ore body in the entry by using a hydraulic fracturing system, and the fracturing is stopped when the observation hole discharges water and the pressure drops sharply; S4, mechanized ore falling, transportation, support and ventilation According to the sequence of forward mining in the entry, interval mining between entries in the sub-layer and upward mining from the lower sub-layer to the upper sub-layer in the ore block, the ore body after pre-cracking is mechanically cut and continuously fallen by using a digging and anchoring machine, the ore is unloaded from the tail of the digging and anchoring machine to the telescopic scraper conveyor embedded in the bottom plate of the entry, then is transferred to the chute through the scraper conveyor laid in the center of the bottom plate of the through vein, the ore discharged from the chute is unloaded to the transportation equipment of the stage transportation roadway and is transported to the shaft bottom station for hoisting to the ground surface, the digging and anchoring machine can simultaneously perform anchorage and mesh support on the surrounding rock of the entry, and the scraper conveyor can be lengthened to follow the digging and anchoring machine to move forward, and the ventilation is drawn out to the stage air return roadway through the air duct arranged in the entry, the through vein and the slope; S5, entry subsection subsequent filling After one entry is mined, the mining equipment is removed, the entry is filled in sections according to the cycle distance to ensure that the filling body is fully connected with the roof, a steel reinforcement is laid and a concrete filling is poured to construct a false bottom for the bottom sub-layer, and the remaining sub-layers are filled with cemented tailings, the mining equipment removed after the entry is mined is transported to the next entry, and then steps S1-S5 are repeated to perform mechanical ore falling and continuous mining subsequent filling, and 1-3 entries in the sub-layer of the ore room are simultaneously mined.

2. A method of mechanized continuous mining of a hard rock mine drift according to claim 1, characterized in that: The ore body is a medium-thick or thick ore body with a gentle inclination to a steep inclination.

3. A method of mechanized continuous mining of a hard rock mine drift according to claim 1, characterized in that: The entry section is rectangular, the width of the entry section is 4-8 m, and the height of the entry section is the height of the sub-layer, which is 3-6 m.

4. A method of mechanized continuous mining of a hard rock mine drift according to claim 1, characterized in that: The cross section shape of the stage roadway, segmented transportation roadway, through vein roadway and ramp roadway is one of three-centered arch, straight wall arch, rectangle or trapezoid, and the cross section area is not less than 12m 2 ; the cross section diameter of the chute is not less than 1.0m.

5. A method of mechanized in-mine continuous mining of a hard rock mine access according to claim 1, characterized by: The hydraulic fracturing system comprises a hydraulic geological drilling machine, a fracturing drill rod, a plugging device, a high-pressure hose, a high-pressure water pump and a U-shaped clamping part, the hydraulic geological drilling machine is arranged near a heading face, the high-pressure water pump is connected with the hydraulic geological drilling machine and a water supply pipe of a heading roadway through the U-shaped clamping part and the high-pressure hose with a diameter of 30-60 mm; the fracturing drill rod installed on the hydraulic geological drilling machine is a hollow structure, each section is 1.0-1.5 m long, and can be freely lengthened or shortened by means of the hydraulic geological drilling machine through a threaded connection mode; during fracturing, the fracturing drill rod with a drill bit installed at the front end is first connected with the hydraulic geological drilling machine to drill a fracturing borehole to a certain depth, then the drill bit is removed and a plugging device is installed at the head of the fracturing drill rod, the plugging devices appear in pairs, and a certain length of a thin metal pipe is connected between the two plugging devices, and 1-3 nozzles are radially arranged in the metal pipe.

6. A method of mechanized in-mine development and continuous mining of hard rock mines according to claim 1 or 5, characterized in that: The fracturing in the fracturing borehole is in a forward or backward mode, the fracturing distance is 0.5-2.0 m, two plugging devices are used to implement double-plugging fracturing, the length of the plugging device is 0.5-1.5 m, the diameter is 60-95 mm, and the middle distance is 0.2-0.6 m.

7. A method of mechanized in-mine continuous mining of a hard rock mine access according to claim 5, characterized by: The high-pressure water pump rated pressure is greater than or equal to 50 MPa, and the flow of the high-pressure water pump is greater than or equal to 100 m 3 / min; the pressure resistance of the fracturing drill rod and the high-pressure hose is greater than or equal to 70 MPa.

8. A method of preparing a method of mechanized continuous mining of a hard rock mine drift with ore drop according to claim 1, characterized in that: The scraper conveyor has a conveying distance of ≥120 m and a width of 0.4-0.6 m; the bolting machine is provided with 2-5 sets of hydraulic rock drilling mechanisms with the functions of rock drilling, charging, net hanging and anchor installation.

9. A method of preparing a method of mechanized continuous mining of a hard rock mine drift according to claim 1 or 8, characterized in that: The anchor is one or more of an anchor rod and an anchor cable, the anchor rod is a resin anchor rod with a diameter of 18-25 mm and a length of 2.0-3.0 m, the anchor cable is a steel strand with a diameter of 15-25 mm and a length of 3.0-7.5 m, and the net is one of a metal net and a plastic net.

10. A method of mechanized in-mine continuous mining of a hard rock mine access according to claim 1, characterized by: The filling retaining wall and the concrete false floor are poured with concrete with a grade of C20 or above, the sand-cement ratio of the tailings cemented filling slurry is ≥1:8, and the mass concentration is ≥68%.

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