A safe pillar residual ore recovery method and system for underground mines

Abstract

The application discloses a kind of underground mine pillar residual ore safety mining method and system, to solve the safety problem that filling body structure is not stable in the process of pillar residual ore mining, by being arranged in the upward blast hole drilled in the pillar to be mined ore body in the pillar mining area Energy-absorbing buffer air bag, form airtight space at the bottom of upward blast hole, by pressure pipeline injects rock base adhesive into the airtight space at the bottom of hole, grouting repair is carried out to filling body fracture, after repair, energy-absorbing buffer air bag is retained at the bottom of blast hole, absorbs a large amount of mining blasting energy, reduces the impact of mining blasting on goaf filling body, and under the action of blasting, produce annular expansion, accurately control the fracture of mining ore body at the junction with filling body, improve recovery rate.The application combines upward blast hole of mining blasting to carry out overall repair and reinforcement to goaf filling body, effectively weaken the influence of mining blasting energy on goaf filling body, guarantee the safety, efficiency and economy in the process of pillar residual ore mining.

Description

Technical Field

[0001] This invention discloses a method and system for safe mining of residual ore in underground mine pillars, belonging to the field of underground mine pillar residual ore mining technology. Background Technology

[0002] In the mining of pillar ore residue, rock bursts and frequent blasting operations often create numerous fractures in and around the goaf filling. These fractures significantly weaken the overall mechanical properties of the goaf filling, especially its compressive strength and stability, directly impacting the safety and efficiency of pillar ore body mining. Traditional pillar ore residue mining techniques often fail to effectively prevent filling collapse and pillar ore body instability. Furthermore, the propagation of blasting energy and the control of blasting effects further increase the risks and complexities of the mining process.

[0003] In existing mines, when mining the bottom pillar residual ore, a 1.5-2m thick ore body is usually left at the bottom of the goaf filling body as a protective buffer layer. This protective buffer layer is not mined, which reduces the recovery rate of the bottom pillar residual ore.

[0004] For underground mines with high-grade ore, conventional anchoring and support measures are used to reinforce the backfill body in order to improve the recovery rate of the bottom pillar residual ore. For example, Chinese patent application CN120351018A discloses a structural backfill mining method combining gabion mesh masonry-grouting-shotcrete. This method processes the loose gangue generated at the working face into standardized box-shaped gabion mesh gangue masonry bodies, which are then stacked into dry-laid stone strip walls using a lifting and stacking device of a special hydraulic support for backfilling. At the same time, a combined reinforcement method of "external shotcrete + internal grouting" is used to consolidate the dry-laid stone strip walls into a whole, forming several parallel strip-type backfill walls behind the working face. This conventional reinforcement support method has high construction costs and slow construction progress, which does not conform to the "rapid mining and rapid exit" strategy of bottom pillar residual ore. Furthermore, these reinforcement support methods cannot improve the internal fracture conditions of the backfill body in the goaf, so the reinforcement effect on the internal structure of the backfill body is limited.

[0005] Another method involves grouting to repair internal fissures in the goaf filling body, thereby reinforcing it and improving its overall strength. For example, Chinese patent application CN116517544A discloses a three-in-one gangue cemented downward filling method for extremely close-range coal seams. However, this grouting repair method requires drilling grouting holes from the surface or above the goaf filling body downwards, utilizing gravity or pressure to penetrate the grout into the internal fissures. This method increases the construction cost of grouting holes, and since grouting repair and mining operations are not on the same working plane, it is difficult to achieve efficient coordinated operation of goaf filling grouting repair and bottom pillar residual ore mining. Summary of the Invention

[0006] The technical problem solved by this invention is to provide a method and system for safe mining of residual ore in underground mine pillars, addressing the aforementioned problem of instability of the upper filling structure caused by blasting energy during the bottom pillar mining operation.

[0007] This invention is achieved using the following technical solution:

[0008] This invention first discloses a method for the safe recovery of residual ore from pillars in underground mines, comprising the following steps:

[0009] Step 1: Explore the filling material above the bottom pillar mining body to obtain the fracture condition and physical and mechanical strength of the filling material above the bottom pillar mining area, and design the mining blasting parameters accordingly.

[0010] Step 2: Drill upward blast holes in the bottom pillar mining area to be mined. The upward blast holes penetrate the bottom pillar mining body until the bottom of the blast hole is connected to the filling body fracture.

[0011] Step 3: Place an energy-absorbing buffer airbag at the bottom of the upward blast hole to form a sealed space at the bottom of the upward blast hole. Inject rock matrix adhesive into the sealed space at the bottom of the hole through a pressure pipeline to grout and repair the cracks in the filling body that are connected to the bottom of the upward blast hole. After the cracks in the filling body are repaired, leave the energy-absorbing buffer airbag at the bottom of the blast hole.

[0012] Step 4: Load explosives into the upward blast holes according to the designed mining blasting parameters, and carry out mining blasting in this mining area;

[0013] Step 5: After the blasting is completed, the fallen ore is shoveled away, and the stability of the backfill above the mining area after blasting is checked, and the mining blasting parameters for the next mining cycle are adjusted accordingly.

[0014] In a method for safe recovery of residual ore in an underground mine pillar according to the present invention, further, in step two, when drilling upward blast holes, a laser measuring device or a digital level is used to ensure that the direction of the upward blast holes is perpendicular to the bottom of the filling body, so as to minimize the impact of the explosive stress wave in the upward blast holes on the upper filling body, and make the explosive energy in the blast holes that propagates radially to the filling body as small as possible.

[0015] In a method for safe recovery of residual ore in an underground mine pillar according to the present invention, further, in step three, the energy-absorbing buffer airbag is connected to the inflation pipe. After the energy-absorbing buffer airbag is placed into the upward blast hole to a predetermined position at the bottom of the hole in a partially inflated state, the energy-absorbing buffer airbag is fully inflated by connecting the inflation pipe to the external inflation device. The outer peripheral wall of the energy-absorbing buffer airbag is pressed into contact with the hole wall of the upward blast hole, forming a seal at the bottom of the upward blast hole. This prevents the rock matrix adhesive from flowing back into the upward blast hole and affecting subsequent charging operations during the process of penetrating the fractures of the filling body.

[0016] In a method for safe recovery of residual ore in an underground mine pillar according to the present invention, the pressure pipeline is further connected to an energy-absorbing buffer airbag and is sent together with the energy-absorbing buffer airbag into the sealed space formed by the upward blast hole and the bottom of the upward blast hole.

[0017] In a method for safe mining of residual ore at the bottom pillar in an underground mine according to the present invention, the energy-absorbing buffer airbag is further detachably connected to the inflation pipe and the pressure pipeline. After the grouting repair is completed, the inflation pipe and the pressure pipeline are separated from the energy-absorbing buffer airbag and extracted from the upward blast hole. After repairing and filling the internal cracks of the filling body, the energy-absorbing buffer airbag is left at the bottom of the upward blast hole. The elastic effect of the energy-absorbing buffer airbag is further utilized to absorb the explosive energy propagated axially through the upward blast hole, thereby reducing the impact of mining blasting on the upper filling body.

[0018] In a method for safe mining of residual ore in an underground mine pillar according to the present invention, the rock-based adhesive in step three is polyurethane foam, which has high cohesion and good mechanical properties, can maintain stability under high pressure, and can effectively penetrate the cracks of the filling body to form a stable bonding layer, thereby enhancing the overall stability of the filling body. This significantly improves the filling body's ability to resist the destructive effects of explosive stress waves and explosive gases propagating axially through the upward blast hole.

[0019] This invention also discloses a safe recovery system for residual ore in underground mine pillars, comprising:

[0020] The exploration module explores the filling material above the bottom pillar ore body to be mined, and obtains the fracture condition and physical and mechanical strength of the filling material above the bottom pillar mining area, which serves as the basis for the design of mining blasting parameters.

[0021] The drilling equipment drills upward blast holes in the bottom pillar mining area, and the upward blast holes penetrate the bottom pillar mining body until the bottom of the blast hole is connected to the fissure of the filling body.

[0022] The grouting repair module involves placing an energy-absorbing buffer airbag at the bottom of the borehole to form a sealed space. Rock matrix adhesive is then injected into this sealed space through a pressure pipeline to grout and repair the cracks in the filling material that are connected to the bottom of the borehole. After the cracks in the filling material are repaired, the energy-absorbing buffer airbag is left at the bottom of the borehole.

[0023] The explosive charging and blasting module charges and blasts the upward blast holes according to the designed mining blasting parameters;

[0024] After blasting, shovel and transport equipment is used to shovel and transport the fallen ore.

[0025] The re-exploration module checks the stability of the backfill above the mining area after blasting and adjusts the mining blasting parameters for the next mining cycle accordingly.

[0026] In a safe recovery system for residual ore in an underground mine pillar according to the present invention, the energy-absorbing buffer airbag has an annular cavity connected to an inflation pipe. The pressure pipe passes through the outer channel of the central airbag of the energy-absorbing buffer airbag and connects to the sealed space at the bottom of the hole. When fully inflated, the outer peripheral wall of the energy-absorbing buffer airbag is in tight contact with the hole wall of the upward blast hole, and the inner peripheral wall squeezes the outer channel of the central airbag and the pressure pipe to form a tight contact, thereby achieving a sealed contact between the airbag and the upward blast hole, and between the airbag and the pressure pipe.

[0027] In a safe recovery system for residual ore in an underground mine pillar according to the present invention, the outer channel of the central airbag of the energy-absorbing buffer airbag is provided with a sealing pipe, and the center of the sealing pipe is provided with an axially penetrating slit. The pressure pipeline includes a grouting hose and a rigid grouting insertion pipe. The grouting insertion pipe is inserted into and penetrates the central slit of the sealing pipe and expands the slit to form the cavity of the sealing pipe. The grouting hose and the grouting insertion pipe are connected to the side near the upward blast hole opening and extend to connect to the rock-based adhesive pressure device outside the upward blast hole.

[0028] In a safe recovery system for residual ore in an underground mine pillar according to the present invention, the energy-absorbing buffer airbag is provided with a hard pad on the side near the opening of the upward blast hole, and the outer diameter of the pad is smaller than the diameter of the upward blast hole.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) It solves the problem of rapid and effective reinforcement of fractures in the backfill body. By using pressure equipment, cohesive rock-based adhesive foam can be injected into the fracture group of the backfill body through the upward blast holes drilled during the bottom pillar mining, thereby enhancing the overall stability of the backfill body. Directly utilizing the upward blast holes drilled during mining operations allows for rapid construction, reduces additional support and backfill body repair costs, and avoids the problem of explosive gas intruding into the fractures during mining, which would exacerbate the fracture of the backfill body.

[0031] (2) The radial explosive stress wave propagating in the filling body is weakened to the greatest extent. The blast hole involved in this invention is an upward vertical blast hole, which can reduce the drilling length and time of the blast hole, and also allow the radial explosive stress wave of the explosive after blasting to propagate as much as possible in the bottom pillar ore body, and the explosive stress wave energy propagating into the filling body is minimized, thus avoiding the expansion of cracks in the filling body induced by the explosive stress wave to the greatest extent.

[0032] (3) Energy-absorbing buffer airbags are used to assist in sealing the cracks in the filling body. At the same time, during the mining blasting stage, energy-absorbing buffer airbags are used to absorb the axial explosion energy in the blast hole, reduce the impact of the axial explosion energy in the blast hole on the filling body, and further ensure the structural stability of the filling body in the goaf.

[0033] (4) Energy-absorbing buffer airbags are used to absorb energy and compress it to expand and break the surrounding ore body. Under the action of axial explosion energy in the borehole, the energy-absorbing buffer airbags are compressed along the axial direction. This process absorbs most of the explosion energy along the axial direction of the borehole, preventing the blasting energy from being transmitted into the filling body along the axial direction of the borehole. At the same time, the energy absorbed is converted into mechanical energy of compression and expansion. The expanded airbags apply compressive stress to the ore body in the bottom area of ​​the borehole, causing the ore body around the bottom of the borehole that is not loaded with explosives to be destroyed under the expansion and cracking action of the airbags. This reduces the amount of ore body remaining near the filling body, significantly improves the mining effect, and reduces the overall block ratio.

[0034] (5) Green and environmentally friendly and low cost. The rock-based adhesive foam and airbags used in this invention are inexpensive. Compared with the existing filling body support method, the construction operation is more convenient. Combined with the use of the upward blast holes of the mining blasting, the overall operation cycle is shorter, which reduces the cost of safety support operation for residual ore mining.

[0035] (6) Improve the overall efficiency and safety of mining operations. The mining method of the present invention not only improves the overall stability of the backfill body, but also effectively shortens the construction time, increases the recovery rate of residual ore, improves the overall efficiency of mining operations, and significantly reduces the safety risk of backfill body collapse during mining operations.

[0036] In summary, the present invention provides a method and system for safe mining of residual ore in underground mine pillars, which combines upward blast holes from mining blasting to repair and reinforce the filling body in the goaf, and can effectively reduce the impact of mining blasting energy on the filling body in the goaf, thus ensuring safety, efficiency and economy in the mining process of residual ore in pillars.

[0037] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0038] Figure 1 This is a flowchart of the recovery method steps of the present invention.

[0039] Figure 2 This is a cross-sectional schematic diagram of the mining operation in the embodiment.

[0040] Figure 3 This is a schematic diagram illustrating the grouting repair of the goaf filling body through upward blast holes in the embodiment.

[0041] Figure 4 This is a partial schematic diagram of an energy-absorbing buffer airbag placed at the bottom of an upward-facing borehole to form a sealed space, as shown in the embodiment.

[0042] Figure 5 This is a partial schematic diagram of the energy-absorbing buffer airbag remaining at the bottom of the upward-facing blast hole after grouting is completed, as shown in the embodiment.

[0043] Figure 6 This is a schematic diagram of the upward-facing borehole charging structure in the embodiment.

[0044] Numbering in the diagram: 1-filling body, 2-filling body fissure, 3-rock base adhesive, 4-bottom pillar ore body to be recovered, 5-upward blast hole, 51-energy-absorbing buffer airbag, 511-sealing pipe, 512-grouting pipe, 513-pad, 514-one-way valve, 52-explosive section, 53-hole plugging section, 6-bottom ore body access stope, 7-falling ore blast pile, 8-pressure pipeline, 81-grouting hose, 82-air inflator pipe, 9-rock base adhesive pressure equipment. Detailed Implementation

[0045] Example

[0046] See also Figure 1 and Figure 2 The diagram illustrates a process flow of a safe recovery method for residual ore in underground mine pillars according to the present invention, which specifically includes the following steps:

[0047] S1. Exploration is carried out on the filling body 1 above the bottom pillar mining body 4, and mechanical strength test of the filling body is conducted to obtain the fracture condition and physical and mechanical strength of the filling body 1 above the bottom pillar mining area. Based on this, the mining blasting parameters are designed, including the borehole diameter, borehole distribution density and charge structure.

[0048] S2. Drill upward blast holes 5 in the bottom pillar mining area for the bottom pillar ore body 4 to be mined. The upward blast holes 5 penetrate the bottom pillar ore body 4 to be mined until the bottom of the blast hole is connected to the filling body fracture.

[0049] In this step, upward blast holes 5 are drilled in the access roadway of the bottom ore body access stop 6 using drilling equipment. Laser measuring equipment or a digital level is used to ensure that the direction of the upward blast holes 5 is perpendicular to the bottom of the backfill 1. The perpendicularity of the upward blast holes 5 to the backfill ensures that the explosive stress wave propagating radially to the backfill within the upward blast holes 5 has the least possible explosive energy, minimizing the impact of the mining blast on the upper backfill. The length of the upward blast holes 5 is equal to or greater than the thickness or height of the bottom pillar ore body 4 to be mined, ensuring the recovery rate of all bottom pillar ore bodies 4. The diameter of the blast holes 5 is determined according to the mining blasting parameters used.

[0050] S3. An energy-absorbing buffer airbag 51 is placed at the bottom of the upward-facing borehole 5, forming a sealed space at the bottom of the borehole 5. Rock-based adhesive 3 is injected into this sealed space through a pressure pipe 8 to grout and repair the fractures 2 in the filling material that connect to the bottom of the upward-facing borehole. Figure 3 As shown, after the filling body crack 2 is repaired, the energy-absorbing buffer airbag 51 is retained at the bottom of the borehole.

[0051] In this step, the energy-absorbing buffer airbag 51 is connected to the inflation pipe 82. The energy-absorbing buffer airbag 51, in a partially inflated state, is placed into the upward-facing borehole 5 to a predetermined position at the bottom of the hole. The position of the energy-absorbing buffer airbag 51 is aligned with the contact boundary between the bottom pillar and the ore body to be recovered and the filling body. The energy-absorbing buffer airbag 51 is then fully inflated by connecting it to an external inflation device via the inflation pipe 82. Figure 4 As shown, the outer peripheral wall of the energy-absorbing buffer airbag 51 is pressed tightly against the borehole wall of the upward blast hole 5, forming a seal at the bottom of the upward blast hole 5. The inflation device can be provided with inflation pressure by the press on the rock-based adhesive pressure device 9, so that the rock-based adhesive 3 injected into the sealed space at the bottom of the hole through the pressure pipeline 8 can penetrate into the filling body fissure 2 without the rock-based adhesive 3 flowing back into the upward blast hole and affecting subsequent charging operations. The schematic diagram after the rock-based adhesive 3 penetrates into the filling body fissure 2 and completes the filling body repair is shown below. Figure 5 As shown.

[0052] The pressure line 8 is connected to the energy-absorbing buffer airbag 51. When the energy-absorbing buffer airbag 51 is placed into the upward blast hole 5, the pressure line 8 is sent into the upward blast hole 5 along with the energy-absorbing buffer airbag 51, and communicates with the sealed space formed at the bottom of the upward blast hole after the energy-absorbing buffer airbag 51 is in place. At the same time, the energy-absorbing buffer airbag 51 is detachably connected to the inflation pipe 82 and the pressure line 8. The specific detachable connection structure can refer to the structure of a spherical inflation nozzle. After the grouting repair is completed, the inflation pipe 82 and the pressure line 8 are separated from the energy-absorbing buffer airbag 51 and pulled out of the upward blast hole to avoid the inflation pipe 82 and the pressure line 8 affecting the charge structure inside the upward blast hole. After repairing and filling the internal cracks of the filling body, the energy-absorbing buffer airbag 51 is left at the bottom of the upward blast hole 5. The elasticity of the energy-absorbing buffer airbag 51 absorbs the explosive energy propagating axially through the upward blast hole, reducing the damage to the upper filling body structure caused by the mining blast.

[0053] The rock-based adhesive in this invention uses polyurethane foam, a type of foamed rock-based adhesive commonly used for geological damage repair. It possesses high cohesion and good mechanical properties, maintaining stability under high pressure. After positioning the energy-absorbing buffer airbag 51 at a predetermined position at the bottom of the upward blast hole, it is inflated and pressurized through the inflation pipe 82. The pressure source is a pressure pump carried on the rock-based adhesive pressure device 9, ensuring a tight fit between the outer cylindrical surface of the energy-absorbing buffer airbag 51 and the borehole wall. During injection, it is ensured that the polyurethane foam rock-based adhesive does not leak into the lower borehole cavity. Then, the polyurethane foam in the foam generator is pressed into the bottom of the upward blast hole through the pressure pipe 8 via the rock-based adhesive pressure device 9. Under pressure, the polyurethane foam effectively penetrates the cracks 2 of the filling body, forming a stable bonding layer and enhancing the overall stability of the filling body 1. This significantly improves the filling body's ability to resist the destructive effects of axially propagating explosive stress waves and explosive gases from the upward blast hole. After the polyurethane foam rock-based adhesive solidifies and forms cohesive force, the air inlet pipe 82 and pressure pipe 8 are pulled out, leaving the energy-absorbing buffer airbag 51 at the bottom of the upper borehole.

[0054] S4. Charge the upward blast holes according to the designed blasting parameters. The charging structure is as follows: Figure 6 As shown, an energy-absorbing buffer airbag 51 serves as the bottom of the upward blast hole 5. Explosive sections 52 are loaded into the upward blast hole 5 according to the mining blasting parameters. The opening of the upward blast hole 5 is then sealed tightly with stemming material or other plugging materials to form an opening plugging section 53. Mining blasting is then carried out in this mining area. The blasting parameter design for mining blasting is a mature mining technology; therefore, the specific mining charge structure will not be described in detail in this embodiment.

[0055] S5. After the blasting is completed, the fallen ore is shoveled away, and the stability of the backfill above the mining area after blasting is checked, and the mining blasting parameters for the next mining cycle are adjusted accordingly.

[0056] Specifically, once the blasting smoke has dissipated and the permissible operating standards have been met, a remote-controlled loader is used to shovel and transport the ore from the blasted pile 7 in the access roadway. At the same time, a drone is used to check the stability of the upper goaf filling body 1 after the blasting. After the shoveling and transportation are completed and safety is ensured, if the structure of the upper goaf filling body 1 is normal, the next mining cycle will proceed. If the upper goaf filling body 1 collapses, and the collapse is within a controllable range, the mining blasting parameters will be adjusted in the next mining cycle to reduce the amount of explosives in the blast holes.

[0057] See again Figures 2 to 6 This embodiment of the underground mine pillar residual ore safe recovery system includes an exploration module, drilling equipment, grouting and repair module, explosive blasting module, shovel and transport equipment, and a re-exploration module. The exploration module explores the filling material 1 above the ore body to be recovered in the pillar, obtaining the fracture condition and physical and mechanical strength of the filling material 1 above the pillar recovery area, as the basis for designing the recovery blasting parameters. The drilling equipment drills upward blast holes 5 in the pillar ore body 4 to be recovered in the pillar recovery area, ensuring that the upward blast holes 5 penetrate the pillar ore body until the bottom of the blast hole connects with the fracture of the filling material. The grouting and repair module places an energy-absorbing buffer airbag 51 at the bottom of the upward blast hole 5, forming a sealed space at the bottom of the upward blast hole 5. Rock-based adhesive is injected into the sealed space at the bottom of the borehole through pressure pipeline 8 to grout and repair the cracks 2 in the filling body that are connected to the bottom of the upward blast hole. After the cracks in the filling body are repaired, the energy-absorbing buffer airbag 51 is left at the bottom of the blast hole. The charging and blasting module charges and blasts the upward blast hole according to the designed mining blasting parameters. The shoveling and transporting equipment shovels and transports the fallen ore after the blasting. The re-exploration module checks the stability of the filling body above the mining area after the blasting and adjusts the mining blasting parameters for the next mining cycle accordingly.

[0058] The exploration module for inspecting the backfill body uses mature geological testing equipment. The drilling equipment and blasting module select appropriate rock drilling rigs and charging machines based on the specific conditions of the mining area. The shoveling equipment uses unmanned remote-controlled shovels to remotely shovel and transport the blasted ore piles in the mining area. The re-exploration module uses a visual acquisition drone to inspect the backfill body in the blasted goaf. The following section provides a detailed explanation of the grouting repair module, which repairs and reinforces the cracks in the backfill body.

[0059] The grouting repair module includes an energy-absorbing buffer airbag 51, a pressure pipeline 8, and a rock-based adhesive pressure device 9. The layout of these three components in the mining area is as follows: Figure 3 As shown, the energy-absorbing buffer airbag 51, during the grouting repair stage of the filling body fractures, is a sealing airbag into the filling body fractures by injecting the rock matrix adhesive upwards to the bottom of the borehole. (See also...) Figure 4 and Figure 5The energy-absorbing buffer airbag 51 has an annular cavity connected to an inflation tube. The annular cavity has a central airbag outer channel formed by the airbag wall. The pressure pipe 8 passes through the central airbag outer channel of the energy-absorbing buffer airbag 51, and its two ends are respectively connected to the sealed space formed at the bottom of the upward blast hole and the rock-based adhesive pressure device 9 outside the upward blast hole. The annular airbag cavity of the energy-absorbing buffer airbag 51 is connected to the inflation device outside the hole through an inflation tube 82 for inflation. The inflation pressure of the airbag is maintained in the range of 0.5~0.8 bar. When fully inflated, the outer peripheral wall of the energy-absorbing buffer airbag 51 is pressed against the hole wall of the upward blast hole 5, and the inner peripheral wall presses against the central airbag outer channel and the pressure pipe 8, maintaining the seal between the energy-absorbing buffer airbag 51 and the hole wall, and between the energy-absorbing buffer airbag 51 and the pressure pipe 8, forming a sealed space at the bottom of the upward blast hole 5. Then, polyurethane foam rock-based adhesive 3 is injected upwards into the sealed space at the bottom of the borehole 5 through the pressure pipeline 8 via the rock-based adhesive pressure device 9 to repair and reinforce the cracks 2 in the filling body.

[0060] The outer diameter of the energy-absorbing buffer airbag 51 should be slightly smaller than the diameter of the upward-facing borehole, and its length should not be less than 50 cm. It is made of high-strength rubber composite material, which has good elasticity and compressive strength under high temperature and high pressure environments, and can remain stable under the high temperature and strong impact generated by the explosion, avoiding rupture.

[0061] The pressure pipeline 8 uses a grouting hose 81. One end of the grouting hose 81 is connected to the rock-based adhesive pressure device 9, and the other end is connected to the energy-absorbing buffer airbag 51 through the grouting insertion tube 512. The grouting insertion tube 512 is a rigid tube that is inserted into and passes through the outer channel of the central airbag of the energy-absorbing buffer airbag 51. The openings at both ends of the grouting insertion tube 512 connect to both sides of the energy-absorbing buffer airbag 51. The rigid grouting insertion tube 512 can ensure that the energy-absorbing buffer airbag 51 in the inflated state will not crush the pipeline through which the rock-based adhesive passes, so that the injection channel of the rock-based adhesive remains continuous. At the same time, the squeezing action after the energy-absorbing buffer airbag 51 is inflated can keep the grouting insertion tube 512 fixedly inserted in the outer channel of the central airbag, so as to reliably connect the grouting hose 81 and the energy-absorbing buffer airbag 51. After the energy-absorbing buffer airbag 51 expands and is fixed at a predetermined position at the bottom of the upward blast hole, the end of the grouting tube 512 near the opening of the upward blast hole is connected to the grouting hose 81, and is extended through the grouting hose 81 to the rock matrix adhesive pressure device 9 outside the upward blast hole, forming a pipeline for injecting rock matrix adhesive into the sealed space at the bottom of the upward blast hole 5.

[0062] To further ensure the stable insertion of the grouting tube 512 into the outer channel of the central airbag of the energy-absorbing buffer airbag 51, this embodiment provides a sealing tube 511 in the outer channel of the central airbag of the energy-absorbing buffer airbag 51. The sealing tube 511 has an axially penetrating slit at its center. The grouting tube 512 is inserted into and penetrates this slit, expanding to form the cavity of the sealing tube 511. Figure 4 and Figure 5 As shown. Both the energy-absorbing buffer airbag 51 and the sealing tube 511 are made of elastic rubber and are fixedly connected to the outer wall of the outer channel of the central airbag of the energy-absorbing buffer airbag 51. The thickness of the cavity of the sealing tube 511 after being expanded is greater than the wall thickness of the energy-absorbing buffer airbag 51. In this way, the inner wall of the sealing tube 511 maintains elastic compression on the entire axial outer wall of the grouting insertion tube 512, achieving full compression contact with the outer wall of the grouting insertion tube. Even when the energy-absorbing buffer airbag 51 is not inflated, the sealing tube 511 can still keep the grouting insertion tube 512 reliably inserted into the outer channel of the central airbag.

[0063] This embodiment employs the aforementioned structure of the energy-absorbing buffer airbag 51 and grouting tube 512, enabling the separability of the energy-absorbing buffer airbag 51 and the pressure pipeline 8. The grouting tube 512 is made of a metal tube or other rigid tube with high rigidity. The friction between the grouting tube 512 and the sealing tube 511 is less than the friction between the outer wall of the energy-absorbing buffer airbag 51 and the upper borehole wall. By pulling the grouting tube 512 with the grouting hose 81, the grouting tube 512 can be pulled out from the sealing tube 511, while the energy-absorbing buffer airbag 51 remains at the bottom of the upper borehole. Alternatively, a pull rope can be fixedly connected to the grouting tube 512, extending to the outside of the borehole, to prevent the grouting hose 81 and the grouting tube 512 from separating due to pulling. After injecting the rock matrix adhesive 3 into the filling body fissure 2 and then pulling out the grouting tube 512, the opened cavity of the sealing tube 511 returns to a closed gap, such as... Figure 5 As shown, it can still maintain the sealing of the sealed space at the bottom of the upward blast hole. When the energy-absorbing buffer airbag 51 is retained at the bottom of the upward blast hole as a buffer protection structure for the goaf filling body during the mining blast, it provides a better sealing surface for blocking and absorbing the energy of the blast hole mining blast.

[0064] In addition, the inflation tube 82 used for inflating the energy-absorbing buffer airbag 51 is also detachable from the energy-absorbing buffer airbag. The inflation port of the energy-absorbing buffer airbag 51 is equipped with a one-way valve 514. The inflation tube 82 is connected to the inflation port of the energy-absorbing buffer airbag 51 through an inflation pin. The inflation pin is inserted into the inflation port of the energy-absorbing buffer airbag 51 and extends through the inflation tube 82 to the inflation device outside the upward borehole. The configuration of the inflation pin and the one-way valve 514 is the same as that of the inflation nozzle of a ball. The specific structure will be described in detail here. By pulling the inflation pin through the inflation tube 82, the inflation pin can be pulled out from the inflation port of the energy-absorbing buffer airbag 51. After being separated from the inflation tube, the energy-absorbing buffer airbag 51 remains in an inflated state under the action of the one-way valve 514, so that the energy-absorbing buffer airbag 51 is positioned and held in an inflated state at the bottom of the upward borehole 5.

[0065] In order to facilitate the smooth insertion of the flexible energy-absorbing buffer airbag 51 into the upward blast hole, this embodiment provides an annular pad 513 on the side of the energy-absorbing buffer airbag 51 near the opening of the upward blast hole. The outer diameter of the pad 513 is smaller than the diameter of the upward blast hole. The pad 513 facilitates the pushing of the energy-absorbing buffer airbag into the upward blast hole by a long rod. The rigid pad 513 provides a rigid working surface on one side of the energy-absorbing buffer airbag 51. When the energy-absorbing buffer airbag 51 is placed inside the upward borehole, in order to facilitate the smooth entry of the energy-absorbing buffer airbag 51 into the upward borehole, a small amount of gas is first injected into the energy-absorbing buffer airbag 51, without fully inflating the energy-absorbing buffer airbag. At this time, the annular outer circumference of the energy-absorbing buffer airbag is smaller than the diameter of the upward borehole 5. The energy-absorbing buffer airbag 51 is pushed into the upward borehole 5 by pushing the pad 513 with a long rod, avoiding the long rod directly pushing the airbag wall, which would cause changes in the airbag's posture and damage to the airbag. After the energy-absorbing buffer airbag 51 is pushed to the bottom of the upward borehole 5, the energy-absorbing buffer airbag 51 is fully inflated and expanded through the inflation tube until it is pressed tightly against the borehole wall, thus fixing the energy-absorbing buffer airbag 51 at the bottom of the upward borehole.

[0066] The pad 513 is preferably made of a high-strength circular metal sheet. After the upward borehole 5 is loaded with explosives, the pad 513 is located between the energy-absorbing buffer gasbag 51 and the explosive section 52. The pad 513 can isolate the gasbag from the ablation and damage caused by the instantaneous high temperature of the explosive gas, and at the same time, it can evenly transfer the high pressure characteristics of the explosive gas to the energy-absorbing buffer gasbag 51. Under the compression of the explosive gas, the energy-absorbing buffer gasbag 51 can deform, thereby absorbing and weakening part of the explosive stress wave and the impact of the explosive gas. During this process, the energy-absorbing buffer gasbag 51 expands in the circumferential direction. This expansion can promote the fracturing of the bottom pillar ore body near the filling body in the unloaded area at the bottom of the borehole, so that the ore body in this area is subjected to circumferential tensile stress, ultimately reducing the proportion of large blocks.

[0067] In this document, the terms "upper," "lower," "front," "back," "left," "right," "top," "bottom," "inner," "outer," "vertical," and "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used for the clarity of expressing the technical solution and for the convenience of description, and therefore should not be construed as limiting the present invention.

[0068] In this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0069] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for safe mining of residual ore in underground mine pillars, characterized in that, Includes the following steps: Step 1: Explore the filling material above the bottom pillar mining body to obtain the fracture condition and physical and mechanical strength of the filling material above the bottom pillar mining area, and design the mining blasting parameters accordingly. Step 2: Drill upward blast holes in the bottom pillar mining area to be mined. The upward blast holes penetrate the bottom pillar mining body until the bottom of the blast hole is connected to the fracture of the filling body. Step 3: Place an energy-absorbing buffer airbag at the bottom of the upward blast hole to form a sealed space at the bottom of the upward blast hole. Inject rock matrix adhesive into the sealed space at the bottom of the hole through a pressure pipeline to grout and repair the cracks in the filling body that are connected to the bottom of the upward blast hole. After the cracks in the filling body are repaired, leave the energy-absorbing buffer airbag at the bottom of the blast hole. Step 4: Using an energy-absorbing buffer airbag as the bottom of the upward blast hole, charge the upward blast hole according to the designed mining blasting parameters, and carry out the mining blasting of this mining area. Step 5: After the blasting is completed, the fallen ore is shoveled away, and the stability of the backfill above the mining area after blasting is checked, and the mining blasting parameters for the next mining cycle are adjusted accordingly.

2. The method for safe recovery of residual ore from pillars in underground mines according to claim 1, characterized in that: In step two, when drilling upward blast holes, a laser measuring device or a digital level is used to ensure that the direction of the upward blast holes is perpendicular to the bottom of the filling material.

3. The method for safe recovery of residual ore from pillars in underground mines according to claim 1, characterized in that: In step three, the energy-absorbing buffer airbag is connected to the inflation tube. After the energy-absorbing buffer airbag is placed into the upward blast hole to the predetermined position at the bottom of the hole in a partially inflated state, the energy-absorbing buffer airbag is fully inflated by connecting the inflation tube to the external inflation device. The outer peripheral wall of the energy-absorbing buffer airbag is pressed into contact with the hole wall of the upward blast hole, forming a seal at the bottom of the upward blast hole.

4. A method for safe recovery of residual ore from pillars in underground mines according to claim 1, characterized in that: The pressure pipeline is connected to the energy-absorbing buffer airbag and is sent together with the energy-absorbing buffer airbag into the sealed space formed by the upper borehole and the bottom of the upper borehole.

5. A method for safe recovery of residual ore from pillars in underground mines according to claim 3 or 4, characterized in that: The energy-absorbing buffer airbag is detachably connected to the inflation pipe and pressure pipe. After the grouting repair is completed, the inflation pipe and pressure pipe are separated from the energy-absorbing buffer airbag and pulled out towards the blast hole.

6. A method for safe recovery of residual ore from pillars in underground mines according to claim 1, characterized in that: The rock-based adhesive used in step three is polyurethane foam.

7. A safe recovery system for residual ore in underground mine pillars, characterized in that, include: The exploration module explores the filling material above the bottom pillar ore body to be mined, and obtains the fracture condition and physical and mechanical strength of the filling material above the bottom pillar mining area, which serves as the basis for the design of mining blasting parameters. The drilling equipment drills upward blast holes in the bottom pillar mining area, and the upward blast holes penetrate the bottom pillar mining body until the bottom of the blast hole is connected to the fissure of the filling body. The grouting repair module places an energy-absorbing buffer airbag at the bottom of the borehole, forming a sealed space at the bottom of the borehole. Rock matrix adhesive is injected into the sealed space at the bottom of the borehole through a pressure pipeline to grout and repair the cracks in the filling body that are connected to the bottom of the borehole. After the cracks in the filling body are repaired, the energy-absorbing buffer airbag is left at the bottom of the borehole. The explosive charging and blasting module uses an energy-absorbing buffer airbag as the bottom of the upward blast hole, and charges and blasts the upward blast hole according to the designed mining blasting parameters. After blasting, shovel and transport equipment is used to shovel and transport the fallen ore. The re-exploration module checks the stability of the backfill above the mining area after blasting and adjusts the mining blasting parameters for the next mining cycle accordingly.

8. A safe recovery system for residual ore in underground mine pillars according to claim 7, characterized in that: The energy-absorbing buffer airbag has an annular cavity connected to an inflation tube. The pressure line passes through the central airbag outer channel of the energy-absorbing buffer airbag and connects to the sealed space at the bottom of the borehole. When fully inflated, the outer peripheral wall of the energy-absorbing buffer airbag is pressed against the borehole wall of the upward blast hole, and the inner peripheral wall presses against the central airbag outer channel and the pressure line, thus achieving a sealed contact between the energy-absorbing buffer airbag and the upward blast hole, and between the energy-absorbing buffer airbag and the pressure line.

9. A safe recovery system for residual ore in underground mine pillars according to claim 8, characterized in that: The central airbag of the energy-absorbing buffer airbag is provided with a sealing tube in the outer channel. The sealing tube has an axially penetrating slit in the center. The pressure pipeline includes a grouting hose and a rigid grouting insertion tube. The grouting insertion tube is inserted into and penetrates the central slit of the sealing tube and expands the slit to form the cavity of the sealing tube. The grouting hose and the grouting insertion tube are connected to the side near the upward blast hole opening and extend to the rock-based adhesive pressure device outside the upward blast hole.

10. A safe recovery system for residual ore in underground mine pillars according to claim 8 or 9, characterized in that: The energy-absorbing buffer airbag has a rigid pad on the side near the upward blast hole opening, and the outer diameter of the pad is smaller than the diameter of the upward blast hole.

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