Pre-splitting blasting device for filling and dewatering superfine tailings and dewatering method

Abstract

The invention discloses a pre-splitting blasting device for filling and dewatering superfine tailings and a dewatering method, and relates to the technical field of mine filling. The pre-splitting blasting device comprises the following steps that S1, a pre-splitting blast hole is calibrated; s2, filling a bamboo cane medicine package; s3, fracture network drainage; and S4, intensity water level monitoring. According to the method, the blast holes with the multiple cracks are formed through presplitting blasting, the filling body containing water can be conveniently communicated, overflow water can be introduced into the presplitting blast holes like trickles, and the method is used for secondary discharge of filling overflow water in a stope. The problems that due to the fact that a large amount of overflow fine tailings are mixed, the size fraction of filling aggregate becomes finer, and the viscosity of slurry is increased after flocculating settling are solved. The reasonable and effective blast hole pre-splitting blasting technology is adopted, blast hole cracks are expanded, the drainage function of the filling stope is recovered and improved, and the method has extremely important significance for ensuring safe and efficient production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mine filling, in particular to a pre-splitting blasting device and method for dewatering of ultra-fine tailings filling. BACKGROUND

[0002] Ultra-fine tailings dewatering is a core technology for realizing the resource utilization of tailings in mine engineering, which refers to the technology of preparing high-concentration slurry or paste from ultra-fine tailings (particle size usually <20μm, accounting for more than 40%) produced by ore dressing through physical / chemical methods to remove water, and using it to fill underground goaf or surface stockyard. Its principle is based on gravity settling, mechanical dewatering, flocculation bridging and other mechanisms: tailings are accelerated to settle in the thickener by flocculating agent, fine particles form flocculation through "bridging effect", and solid-liquid separation is realized; the dewatered paste is transported to the stope through pipeline, and forms a stable support body after filling and consolidation, which not only reduces the pressure of tailings pond, but also improves the recovery rate of mining.

[0003] Previously, graded coarse tailings were used as filling aggregate, and now the graded coarse tailings are screened, and the relatively coarse graded tailings after screening are used as green building materials for external sales. The insufficient filling aggregate is supplemented by overflow fine tailings discharged into the tailings pond, so the composition of the cemented filling aggregate of the mine at this stage is composed of graded coarse tailings after screening and overflow fine tailings, and the cementing material still uses the existing cementing material. However, in the existing ultra-fine tailings dewatering process, due to the mixing of a large amount of overflow fine tailings, the particle size of the filling aggregate becomes finer, and after flocculation and sedimentation, the slurry viscosity increases. During the filling operation, dewatering is often difficult, and after the bottom structure of the stope is preliminarily consolidated within a short period of time (15 days), the filter pipe is already blocked and no longer drains water. In this way, the overflow water accumulated in the stope will form a large static pressure on the sealing door of the filling stope, which constitutes a large safety hazard, and measures must be taken to discharge the overflow water in the stope again.

[0004] There are related invention patents related to tailings dewatering, as follows:

[0005] Chinese patent application number: CN201710312801.5, the invention patent name is: a forced dewatering device and method for full tailings filling stope, the invention relates to underground filling dewatering technical field, in particular to a forced dewatering device and method for full tailings filling stope, the device includes a dewatering pipe, an air extraction device and a valve; the dewatering method comprises the following steps: step one, installing a fixed anchor rod; step two, installing the forced dewatering device for full tailings filling stope; step three, carrying out full tailings filling operation; step four, the dewatering process starts, first, the valve 4 at the end of the dewatering pipe 1 is closed, then the air extraction device 2 is opened to extract air for 5 min; step five, the water seeping in the dewatering pipe is released after the air extraction process is completed; step six, after no water flows out of the dewatering pipe 1, steps four and five are repeatedly circulated multiple times until the filling operation is completed and no water flows out of the dewatering pipe 1; the invention solves the dewatering problem of full tailings filling operation, greatly improves the stope dewatering speed, reduces the process cycle time, and ensures the smooth progress of the filling process, which is convenient to operate in practical application.

[0006] But in the above-mentioned existing patent, although the dewatering problem of full tailings filling operation can be solved, the stope dewatering speed is greatly improved, the process cycle time is reduced, and the filling process is ensured to proceed smoothly. However, if the surrounding rock of the filling stope has poor water permeability, when the overflow water in the cemented filling stope mixed with superfine tailings cannot be discharged, it often seeps down along the cracks between the goaf and the partially cemented filling body, causing large-scale water gushing in the surrounding roadway of the ore extraction access of the filling stope, which poses a threat to the stability of the roadway and constitutes a safety risk, and also seriously affects the consolidation of the filling slurry and reduces the filling quality, which is not conducive to the safety management of the mine and affects the sustainable and stable production of the mine. SUMMARY

[0007] The purpose of the present application is to provide a pre-splitting blasting device and dewatering method for superfine tailings filling dewatering, which solves the problem of secondary discharge difficulty of filling overflow water in the stope in the prior art.

[0008] The present application provides a dewatering process and method for cemented filling of superfine tailings, which greatly improves the secondary dewatering efficiency of the cemented filling stope containing superfine tailings, reduces the net water pressure of the filling closure door, and improves the compressive strength of the underground filling body, ensuring the quality of the filling body and optimizing the economic and technical indicators of the two-step stope recovery; and it is convenient for on-site construction, can effectively handle and improve the drainage function of the filling stope, and is well applied in mines.

[0009] The utility model provides a kind of pre-splitting blasting device for ultrafine tailings filling dehydration, including stope and pre-splitting blasthole, it is characterized in that, two pre-splitting blastholes are provided, two pre-splitting blastholes are in double-hole collaborative layout, and two pre-splitting blastholes will form fissure blasthole, the bottom of pre-splitting blasthole is communicated with stope water pool bottom and stope wall, the inside of pre-splitting blasthole is provided with several strip cartridges, the outside of several strip cartridges in the same hole is provided with elongated bamboo strip, and the elongated bamboo strip is used to link several strip cartridges, air interval is provided between several strip cartridges, and strip cartridge, air interval and elongated bamboo strip are used to form axial decoupling charge structure. Through the collaborative effect of two pre-splitting blastholes, more uniform and continuous pre-splitting crack is formed, stope water pool and wall are effectively isolated, and it is ensured that crack extends along design direction. This layout can reduce overbreak / underbreak phenomenon, improve wall flatness by more than 30%, while reducing the damage of blasting vibration to retained rock mass.

[0010] As a further improvement of the utility model, the side of the elongated bamboo strip is longitudinally arranged with an in-hole detonating cord, which connects the several strip cartridges and extends to the orifice, the orifice is filled with fine yellow sand, the top end of the fine yellow sand is provided with a blasthole plug, the top end of the fine yellow sand is fixedly connected with an electronic detonator through the blasthole plug, and the strip cartridge, elongated bamboo strip, in-hole detonating cord and blasthole plug form a four-in-one detonation device. The in-hole detonating cord is longitudinally arranged on the side of the elongated bamboo strip to form a continuous detonation path, ensuring that all strip cartridges in the same blasthole are synchronously initiated within a microsecond time difference. This design avoids the problem of accompanying explosion caused by line failure or time difference of traditional electric detonator, and improves the uniformity and continuity of pre-splitting crack by more than 40%.

[0011] As a further improvement of the present invention, the bottom end of the pre-splitting blast hole is provided with an original water filter pipe. After the original water filter pipe fails, a new water flow path will be formed by the detonation device. The new water flow path is jointly formed by the blast hole fracture and the pre-splitting blast hole. A pore water flow guide channel is provided on the side of the pre-splitting blast hole near the rock wall. A consolidation drip water flow path is provided on the side of the pore water flow guide channel near the pre-splitting blast hole. The pre-splitting blast hole, the fracture water flow guide channel, and the new water flow path will form a three-stage drainage system. The consolidation drip water at the bottom of the stope flows into the new water flow path through the pre-splitting blast hole along the pore water flow guide channel. A waterproof sealing structure is provided at the connection between the blast hole plug and the detonating cord inside the blast hole. The fracture blast hole formed by the pre-splitting blast and the original water filter pipe form a redundant drainage system. When the original water filter pipe fails due to blockage, aging, or accumulation of ultrafine tailings, the fracture blast hole formed by the pre-splitting blast can automatically take over the drainage function, forming a dual-channel drainage system. This redundant design enhances the system's resilience to failure, ensuring continuous drainage even during fluctuations in the water level of the stope's sump or during filter pipe maintenance, thus avoiding the risk of dehydration stagnation or stope water accumulation due to single-path failure.

[0012] A dewatering method for backfilling and dewatering of ultrafine tailings specifically includes the following steps:

[0013] S1, Pre-splitting borehole calibration: Pre-splitting boreholes are constructed on the top plate outside the closed gate according to the design parameters, and the azimuth and dip angles are calibrated using a total station;

[0014] S2, Bamboo strip explosive pack filling: Install strip-shaped explosive packs on thin bamboo strips, set air gaps between the explosive packs, fill the openings with fine yellow sand and fix the detonation device;

[0015] S3, fracture network drainage: After the network detonation, a fracture network is formed, and the bottom water of the water pool is discharged through one pre-fractured blast hole, while another pre-fractured blast hole is used to discharge seepage water from the wall.

[0016] S4, Intensity Water Level Monitoring: Monitoring the rate of water level decline and the consolidation strength of the filling material.

[0017] As a further improvement of the present invention, in step S1, the diameter of the pre-splitting blast hole is 90mm, the internal inclination angle of the pre-splitting blast hole is 40°~45°, the bottom of the pre-splitting blast hole is ≥1.5m from the bottom of the stope water accumulation pool, and the distance between the pre-splitting blast hole and the stope sidewall is ≤0.3m. Through precise engineering control, fracture directional guidance, and safety boundary setting, the synergistic optimization of drainage efficiency, structural safety, and construction feasibility is achieved in the ultrafine tailings backfilling and dewatering scenario.

[0018] As a further improvement of the present invention, in step S2, the weight of the strip-shaped explosive charge is dynamically adjusted to 8 × 0.1 kg / m³ according to the density of the filling body; the size of the air gap between the explosive charges is set to 0.4–0.8 m; the fine yellow sand is yellow sand with a fineness modulus of 2.0–2.5; the amount of fine yellow sand filling the pre-splitting blast hole is accurate to ±0.1 m³; the strip-shaped explosive charge is fixed by binding the slender bamboo strips with double-strand nylon rope; the sand filling at the blast hole opening adopts a layered compaction technique; the thickness of each layer of the layered compaction is ≤0.3 m; and the compaction density of the layered compaction is ≥85%. Through four dimensions—dynamic adaptation of explosive charge, controlled detonation of air gap, control of sand compaction density, and enhanced binding process—a synergistic breakthrough is achieved in the scenario of ultra-fine tailings filling and dewatering, resulting in precise blasting effect, improved structural stability, and optimized drainage efficiency.

[0019] As a further improvement of the present invention, in step S3, the fracture network connects the water accumulation layer and the water storage layer within the stope; the wooden plug at the orifice of the pre-fractured blast hole is used to maintain a continuous drainage channel; the length of the detonating cord inside the blast hole during the networked detonation must be ≥1.2 times; the delay time error of the electronic detonator is ≤5ms; the delay error of the electronic detonator is used to ensure the synchronous formation of the fracture network; the detonating cord inside the blast hole and the electronic detonator are connected with dual redundancy; and the wooden plug at the blast hole is reinforced with expansion bolts. Through three core strategies—fracture network communication optimization, enhanced detonation synchronization, and improved structural reliability—a comprehensive upgrade in drainage efficiency, system stability, and safety redundancy is achieved in the ultrafine tailings backfilling and dewatering scenario.

[0020] As a further improvement of the present invention, in step S4, the 7-day strength of the consolidation strength of the filling body is guaranteed to be ≥1.2MPa, and the 28-day strength of the consolidation strength of the filling body is guaranteed to be ≥2.0MPa. The consolidation strength of the filling body is monitored in real time by a non-destructive testing instrument. After the blasting is completed, the crack width is measured by an ultrasonic testing instrument, and the crack width must be ≥2cm. The water level drop rate is monitored by a flow meter, and the water level drop rate must be ≥10m³ / h. Through four core strategies—strength time sequence control, non-destructive dynamic monitoring, crack size assurance, and accurate flow measurement—closed-loop management with structural safety, process controllability, and quantifiable efficiency is achieved in the ultrafine tailings filling and dewatering scenario.

[0021] Compared with the prior art, the beneficial effects of this invention are as follows:

[0022] 1. The numerous cracks created by pre-splitting blasting facilitate the connection of water-bearing backfill material, allowing overflow water to be introduced into the pre-splitting blast holes as a trickle for secondary drainage of backfill overflow water within the stope. This addresses the issue that the inclusion of a large amount of fine tailings from the overflow makes the backfill aggregate particle size finer, increasing the viscosity of the slurry after flocculation and sedimentation, making it prone to clogging and preventing water seepage. Employing reasonable and effective pre-splitting blasting technology to enlarge the blast hole fissures and restore and enhance the drainage function of the backfill stope is of paramount importance for ensuring safe and efficient production.

[0023] 2. A dual-hole collaborative layout is adopted, using a non-coupled axial charging structure with slender bamboo strips connecting strip-shaped explosive charges and air gaps to form a through-hole fracture. The bottom of the hole is directly connected to the sidewall and water collection pool, ensuring the continuity and integrity of the pre-fractured zone. This will improve the uniformity of fractures by more than 30%, significantly improve the flatness of the wall surface, and reduce over-excavation / under-excavation.

[0024] 3. The air gaps formed by stringing together strip-shaped explosive charges with slender bamboo strips, combined with the axially decoupled structure, can reduce blasting costs, make positioning more precise, distribute energy more evenly, reduce damage to the remaining rock mass, and thus improve porosity.

[0025] 4. A four-in-one detonation device, consisting of a strip-shaped explosive charge, a thin bamboo strip, a detonating cord inside the borehole, and a wooden plug in the borehole, secures the electronic detonator with the wooden plug. This makes the system structure more stable, the detonator positioning more precise, and the anti-interference capability more improved, thereby ensuring a safe and controllable detonation process.

[0026] 5. By employing a dual-hole system, one hole drains bottom water while the other guides water seepage from the sidewalls, creating a fracture network that directionally connects the water accumulation layer and the water storage layer. If the filter pipe fails, an ignition device creates a new water flow path, forming a three-stage drainage system. This improves drainage efficiency by 40%, provides strong channel stability, includes a failure redundancy scheme, ensures continuous drainage, and reduces maintenance costs.

[0027] 6. Real-time monitoring of the consolidation strength of the filling material is achieved through non-destructive testing instruments, and crack width is measured using ultrasonic testing instruments, while the water level drop rate is monitored using flow meters. This enables closed-loop management that ensures structural safety, process control, and quantifiable efficiency, guaranteeing construction safety and effectiveness, thereby improving consolidation strength.

[0028] 7. Both the slender bamboo strips and the perforated wooden stoppers are natural plant materials. Compared to existing non-degradable metal materials, they can naturally degrade into organic matter after use. This eliminates the risk of plastic pollution and reduces long-term negative impacts on the ecosystem. Furthermore, bamboo has a short growth cycle, and the stoppers can be processed from waste wood. This reduces the consumption of non-renewable resources, promotes a circular economy, and lowers the carbon footprint of the supply chain. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a flowchart of the steps of the present invention.

[0031] Figure 2 This is a diagram showing the location distribution of pre-splitting blast holes in this invention.

[0032] Figure 3 This is a schematic diagram of the pre-splitting blasting of pre-splitting blast holes in this invention.

[0033] Figure 4 This is a diagram showing the charge arrangement of the pre-splitting blast holes in this invention.

[0034] Figure 5 This is a structural diagram of the pre-splitting blast hole in this invention.

[0035] Figure 6 For the present invention Figure 3 A magnified structural diagram of point A in the middle.

[0036] In the diagram: 1. Pre-splitting blast hole; 2. Strip-shaped explosive charge; 3. Fine yellow sand; 4. Pore water flow guide channel; 5. Air gap between explosive charges; 6. Slender bamboo strip; 7. Detonating cord inside the blast hole; 8. Original filter pipe; 9. New water flow path; 10. Drip water flow path after consolidation; 11. Wooden plug for the blast hole; 12. Fractured blast hole. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] A pre-splitting blasting device and dewatering method for ultrafine tailings backfilling, such as Figure 1 As shown, it includes the following steps:

[0039] S1, Pre-splitting borehole calibration: Construct pre-splitting borehole 1 on the top plate outside the closed gate according to the design parameters, and use a total station to calibrate the azimuth and inclination angles. The diameter of pre-splitting borehole 1 is 90mm, the internal inclination angle of pre-splitting borehole 1 is 40°~45°, the bottom of pre-splitting borehole 1 is ≥1.5m from the bottom of the stope water pool, and the distance between pre-splitting borehole 1 and the stope sidewall is ≤0.3m. There are two pre-splitting blast holes 1, which are arranged in a double-hole cooperative layout. The blasting of the two pre-splitting blast holes 1 will form a fracture blast hole 12. The bottom of the pre-splitting blast hole 1 is connected to the bottom of the water accumulation pool and the sidewall of the stope. Several strip-shaped explosive charges 2 are set inside each pre-splitting blast hole 1. The outside of the several strip-shaped explosive charges 2 in the same hole is set with thin bamboo strips 6. The thin bamboo strips 6 are used to tie the several strip-shaped explosive charges 2 in series. Air gaps 5 are set between the several strip-shaped explosive charges 2. The strip-shaped explosive charges 2, the air gaps 5 between the explosive charges, and the thin bamboo strips 6 are used to form an axially uncoupled charging structure.

[0040] Using the calibration of pre-splitting borehole 1 as a comparison condition, the advantages of this invention compared to the prior art are analyzed in detail. The specific comparison table is as follows:

[0041] Table 1 Comparison of Pre-splitting Hole Calibration Technology and Existing Technologies

[0042]

[0043] Based on Table 1 above, it can be concluded that the entire process design of "precise calibration - customized parameters - collaborative layout - optimized charge" solves the problems of insufficient precision, poor parameter adaptability, and unstable fracture control effect in existing technologies. Compared with the extensive construction method that relies on experience in existing technologies, this technology ensures hole position accuracy by calibrating each hole with a total station, avoids environmental interference with clear hole position parameters, enhances fracture penetration effect with dual-hole collaboration, and achieves efficient decoupled charge with low-cost bamboo strip series connection + air gap. Ultimately, it shows significant advantages in improving the quality of the pre-splitting surface, reducing construction costs, and ensuring operational safety, and is more suitable for pre-splitting blasting scenarios in mining areas with water accumulation and wall control requirements.

[0044] S2, Bamboo Strip Charge Packing: Strip-shaped charge packs 2 are installed on slender bamboo strips 6. Air gaps 5 are set between the charge packs 2. Fine yellow sand 3 is filled into the borehole and the detonation device is fixed. The weight of the strip-shaped charge packs 2 is dynamically adjusted to 8 × 0.1 kg / m³ according to the density of the filling material. The size of the air gaps 5 between the charge packs is set to 0.40~0.8m. The fine yellow sand 3 uses yellow sand with a fineness modulus of 2.0~2.5m. The amount of fine yellow sand 3 filling the pre-splitting borehole 1 is accurate to ±0.1m³. The strip-shaped charge packs 2 are fixed with double-strand nylon ropes by the slender bamboo strips 6. The sand filling at the borehole opening of the pre-splitting borehole 1 adopts a layered compaction technique. The thickness of each layer of compaction is ≤0.3m, and the compaction density of the layered compaction is ≥85%. The side of the slender bamboo strip 6 is longitudinally provided with a detonating cord 7 for the borehole. The detonating cord 7 connects several strip-shaped explosive charges 2 and extends to the borehole opening. The borehole opening is sealed with fine yellow sand 3. The top of each fine yellow sand 3 is provided with a borehole plug 11. The top of the fine yellow sand 3 is fixedly connected to the electronic detonator through the borehole plug 11. The strip-shaped explosive charges 2, the slender bamboo strip 6, the detonating cord 7 for the borehole, and the borehole plug 11 are used to form a four-in-one detonation device.

[0045] Using bamboo strip medicine packaging technology as a comparison, the advantages of this invention compared to existing technologies are analyzed in detail, as shown in the following comparison table:

[0046] Table 2 Comparison of Bamboo Strip Packaging Technology and Existing Technologies

[0047]

[0048] Based on Table 2 above, it can be concluded that the loading process of the strip-shaped explosive charge 2 solves the problems of crude parameter control, non-standard processes, and low detonation reliability in existing technologies. Compared with the experience-based construction mode of existing technologies, this technology achieves precise control of the loading process by dynamically adjusting the weight of the explosive charge and specifying the air gap and sand filling parameters. Standardized processes such as fixing with double-strand nylon rope and layered compaction of sand filling improve the stability of construction quality; and the design of the four-in-one detonation device enhances the overall system integrity and safety. Overall, this technology is superior to existing technologies in terms of controllability of blasting effect, construction safety, and resource utilization, and is especially suitable for pre-splitting blasting projects with high requirements for explosive loading accuracy and detonation reliability.

[0049] S3, Fracture Network Drainage: After network detonation, a fracture network is formed. Water from the bottom of the sump is drained through one pre-splitting blast hole 1, and another pre-splitting blast hole 1 is used to drain seepage water from the sidewall. The fracture network connects the sump and aquifer in the stope. The blast hole plug 11 at the opening of the pre-splitting blast hole 1 is used to maintain a continuous drainage channel. During network detonation, the length of the detonating cord 7 inside the blast hole must be ≥1.2 times the length of the electronic detonator. The delay time error of the electronic detonator is ≤5ms. The delay error of the electronic detonator is used to ensure the synchronous formation of the fracture network. The detonating cord 7 inside the blast hole and the electronic detonator are connected with double redundancy. The blast hole plug 11 is reinforced with expansion bolts. The bottom of the pre-splitting blast hole 1 is equipped with an original water filter pipe 8. After the original water filter pipe 8 fails, a new water flow path 9 will be formed by the detonation device. The new water flow path 9 is formed by the fracture blast hole 12 and the pre-splitting blast hole 1. A pore water flow guide channel 4 is set on the side of the pre-splitting blast hole 1 near the rock wall. A consolidated drip water flow path 10 is set on the side of the pore water flow guide channel 4 near the pre-splitting blast hole 1. The fracture blast hole 12, the pore water flow guide channel 4 and the new water flow path 9 will form a three-stage drainage system. The consolidated drip water at the bottom of the stope flows into the new water flow path 9 through the fracture blast hole 12 along the pore water flow guide channel 4. A waterproof sealing structure is set at the connection between the blast hole plug 11 and the detonating cord 7 inside the blast hole. The fracture blast hole 12 formed by the pre-splitting blast and the original water filter pipe 8 form a redundant drainage system.

[0050] Using fracture network drainage technology as a comparison, the advantages of this invention compared to existing technologies are analyzed in detail, as shown in the following comparison table:

[0051] Table 3 Comparison of Fracture Network Drainage Technology with Existing Technologies

[0052]

[0053] Based on Table 3 above, it can be concluded that a complete system of "division of labor layout - precise initiation - three-dimensional drainage - redundancy guarantee" has been constructed around the fracture network drainage system, effectively solving the pain points of existing technologies such as low drainage efficiency, easy channel interruption, and weak risk resistance. Compared with the extensive drainage design of existing technologies, this technology achieves efficient drainage of accumulated water through dual-hole functional division and directional fracture network; ensures synchronous fracture formation through high-precision initiation control, guaranteeing channel integrity; streamlines the water flow path and avoids siltation through a three-level drainage system; and enhances system stability and durability through redundant drainage and waterproof sealing design. Overall, this technology is significantly superior to existing technologies in terms of drainage efficiency, system reliability, and ease of operation and maintenance, providing a more stable and efficient drainage solution for complex water accumulation conditions in mining areas.

[0054] S4, Water Level and Strength Monitoring: Monitor the rate of water level drop and the consolidation strength of the backfill. The 7-day consolidation strength of the backfill must be ≥1.2 MPa, and the 28-day consolidation strength must be ≥2.0 MPa. The consolidation strength of the backfill is monitored in real time using a non-destructive testing instrument. After blasting, the crack width is measured using an ultrasonic testing instrument; the crack width must be ≥2 cm. The rate of water level drop is monitored using a flow meter; the rate of water level drop must be ≥10 m³ / h.

[0055] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pre-splitting blasting device for backfilling and dewatering ultrafine tailings, comprising a stope and pre-splitting blast holes (1), characterized in that, Two pre-splitting blast holes (1) are provided, and the two pre-splitting blast holes (1) are arranged in a double-hole cooperative layout. The blasting of the two pre-splitting blast holes (1) will form a fracture blast hole (12). The bottom of the pre-splitting blast hole (1) is connected to the bottom of the mining area water pool and the mining area wall. The interior of each pre-splitting blast hole (1) is provided with several strip-shaped explosive packets (2). The exterior of several strip-shaped explosive packets (2) in the same hole is provided with slender bamboo strips (6). The slender bamboo strips (6) are used to tie several strip-shaped explosive packets (2) together. Air gaps (5) are provided between several strip-shaped explosive packets (2). The strip-shaped explosive packets (2), the air gaps (5) between explosive packets and the slender bamboo strips (6) are used to form an axially uncoupled explosive charging structure.

2. The pre-splitting blasting device for backfilling and dewatering ultrafine tailings as described in claim 1, characterized in that: The slender bamboo strip (6) has a detonating cord (7) arranged longitudinally on its side. The detonating cord (7) connects several strip-shaped explosive charges (2) and extends to the opening. The opening is filled with fine yellow sand (3). The top of each fine yellow sand (3) is provided with a wooden plug (11). The top of the fine yellow sand (3) is fixedly connected to an electronic detonator through the wooden plug (11). The strip-shaped explosive charges (2), the slender bamboo strip (6), the detonating cord (7), and the wooden plug (11) are used to form a four-in-one detonation device.

3. The pre-splitting blasting device for backfilling and dewatering ultrafine tailings as described in claim 2, characterized in that: The bottom end of the pre-splitting blast hole (1) is provided with an original water filter pipe (8). After the original water filter pipe (8) fails, a new water flow path (9) will be formed by the detonation device. The new water flow path (9) is jointly formed by the fracture blast hole (12) and the pre-splitting blast hole (1). A pore water flow guide channel (4) is provided on the side of the pre-splitting blast hole (1) near the rock wall. A consolidation drip water flow path (1) is provided on the side of the pore water flow guide channel (4) near the pre-splitting blast hole (1). 0), the fracture blast hole (12), the pore water flow guide channel (4) and the new water flow path (9) will form a three-level drainage system. After the bottom of the mining area is consolidated, the dripping water will flow through the fracture blast hole (12) and into the new water flow path (9) along the pore water flow guide channel (4). The connection between the blast hole plug (11) and the detonating cord (7) inside the blast hole is equipped with a waterproof sealing structure. The fracture blast hole (12) formed by the pre-fracture blasting and the original filter pipe (8) form a redundant drainage system.

4. A dehydration method comprising the pre-splitting blasting device according to any one of claims 1 to 3, characterized in that, Specifically, the steps include the following: S1, Pre-splitting borehole calibration: Pre-splitting boreholes (1) are constructed on the top plate outside the closed gate according to the design parameters, and the azimuth and inclination are calibrated using a total station; S2, Bamboo strip medicine pack filling: Install strip medicine packs (2) on slender bamboo strips (6), set air gaps (5) between strip medicine packs (2), fill the openings with fine yellow sand (3) and fix the detonation device; S3, fracture network drainage: After the network detonation, a fracture network is formed, and the bottom water of the water accumulation pool is discharged through one pre-splitting blast hole (1), and another pre-splitting blast hole (1) is used to discharge the seepage water from the wall. S4, Intensity water level monitoring: Monitor the rate of water level drop and the consolidation strength of the filling material.

5. The dewatering method for backfilling and dewatering ultrafine tailings as described in claim 4, characterized in that: In step S1, the diameter of the pre-splitting blast hole (1) is 90mm, the internal inclination angle of the pre-splitting blast hole (1) is 40°-45°, the bottom of the pre-splitting blast hole (1) is ≥1.5m from the bottom of the mining area water pool, and the distance between the pre-splitting blast hole (1) and the mining area wall is ≤0.3m.

6. The dewatering method for backfilling and dewatering of ultrafine tailings as described in claim 5, characterized in that: In step S2, the weight of the strip-shaped explosive pack (2) is dynamically adjusted to 8×0.1kg / m³ according to the density of the filling body. The size of the air gap (5) between the explosive packs is set to 0.4-0.8m. The fine yellow sand (3) is yellow sand with a fineness modulus of 2.0-2.

5. The amount of fine yellow sand (3) filling the pre-splitting blast hole (1) is accurate to ±0.1m³. The strip-shaped explosive pack (2) is tied with a long bamboo strip (6) and fixed with a double-strand nylon rope. The sand filling at the opening of the pre-splitting blast hole (1) adopts a layered compaction technique. The thickness of each layer of the layered compaction is ≤0.3m, and the compaction density of the layered compaction is ≥85%.

7. The dewatering method for backfilling and dewatering of ultrafine tailings as described in claim 6, characterized in that: In step S3, the fracture network connects the water accumulation layer and the water storage layer in the mining area. The blast hole plug (11) at the opening of the pre-splitting blast hole (1) is used to maintain a continuous drainage channel. The length of the detonating cord (7) in the blast hole during the network detonation must be ≥1.2 times. The delay time error of the electronic detonator is ≤5ms. The delay error of the electronic detonator is used to ensure the synchronous formation of the fracture network. The detonating cord (7) in the blast hole and the electronic detonator are connected with dual redundancy. The blast hole plug (11) is reinforced with expansion bolts.

8. The dewatering method for backfilling and dewatering of ultrafine tailings as described in claim 7, characterized in that: In step S4, the 7-day strength of the filling material is guaranteed to be ≥1.2MPa, the 28-day strength of the filling material is guaranteed to be ≥2.0MPa, the consolidation strength of the filling material is monitored in real time by a non-destructive testing instrument, the crack width is measured by an ultrasonic testing instrument after the blasting is completed, the crack width must be ≥2cm, the water level drop rate is monitored by a flow meter, and the water level drop rate must be ≥10m³ / h.

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