Waste mine hole self-filling method

Abstract

The invention discloses a waste mine hole self-filling method, and relates to the technical field of mine ecological restoration and underground space governance, and the method comprises the following steps: firstly, combining unmanned aerial vehicle aerial photography with geological radar to accurately explore mine hole parameters, and mixing mine solid waste, a cementing material and the like in proportion to prepare a solid filling material; a water gushing area is enclosed to form a groove, and a water stop plug is formed after materials are put and stirred; then, a top suspension groove and a side wall lateral groove are built correspondingly, materials are stirred through gushing water, and filling is completed; and finally maintaining and detecting the performance of the filler. According to the method, high-altitude operation equipment and a temporary support are not needed, the method can adapt to the mine holes in different forms, safe and efficient filling in the whole space is achieved, the solid waste utilization rate is high, the filling body stability is high, the problems of inaccurate investigation, poor water gushing plugging and high filling risk in the traditional technology are effectively solved, and the method is suitable for small and medium-sized water gushing waste mine hole treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mine ecological restoration and underground space governance, in particular to a self-filling method for abandoned mine. BACKGROUND

[0002] As underground space left by mining, abandoned mine is prone to water inrush, top floatstone falling off, and side wall fissure water seepage due to long-term idling, which not only constitutes a geological safety hazard, but also may cause ecological risks such as surface subsidence and groundwater pollution, and therefore needs to be filled and governed to realize safety control and ecological restoration.

[0003] The current abandoned mine filling technology has many deficiencies: first, the water inrush treatment is not complete, and the traditional technology mainly uses simple piling of sand or single material to block the water inrush, without combining the water inrush amount to design the volume of the enclosing structure, which often leads to water stop failure due to unbalanced water-material ratio, and the subsequent filling material is easy to be washed away by water inrush; second, the top and side wall filling is difficult, the top filling relies on high-altitude operation platform, the safety risk of construction personnel is high, and the material is easy to fall due to gravity, resulting in insufficient filling density; the side wall filling needs to build temporary support, which not only has high cost and complicated installation and removal, but also is difficult to adapt to the walls with different slopes, and the filling body is easy to fall off after the support is removed; third, the stability of the filling body is poor, the traditional material needs to be mixed with additional water, it is difficult to accurately control the water-material ratio, which easily leads to poor material curing, and the curing scheme is not designed for the humidity environment of the mine, the filling body is easy to have dry shrinkage cracks, and it cannot meet the long-term safe use requirement; fourth, the resource utilization rate is low, the filling material mainly uses purchased sand or special gel, and the solid waste such as waste rock powder and tailings sand left by mining is not effectively utilized, which not only increases the material cost, but also causes pollution of solid waste storage, which does not meet the green mine governance concept.

[0004] In summary, the existing technology cannot simultaneously solve the problems of abandoned mine surveying accuracy, effective water inrush plugging, full-space safe filling, and long-term stability of the filling body, and therefore a full-space self-filling method with strong adaptability, high safety and efficiency, and ecological benefits is needed to fill the current technical gap. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a self-filling method for abandoned mine.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a self-filling method for abandoned mine, comprising the following steps: Step one: using unmanned aerial vehicle aerial photography combined with geological radar to obtain the position of mine water inrush area, water inrush amount, top height, side wall slope and crack distribution in each area; mixing mine solid waste, cementing material, quick-setting agent and binder in a mass ratio to form solid filling material, and sealing and storing after uniform mixing; Step two: enclose the water gushing area with steel plate baffle to form a groove with a volume of 2-3 times the water gushing amount, seal the gap at the bottom of the baffle with quick-setting mortar; pour 2 / 3 of the volume of solid filling material into the groove, stir in multiple times with a portable mixer, each time interval 4-8 minutes, and let stand for 30-60 minutes to form a water stop plug to block the water gushing point, leaving the remaining solid material in the groove for use; Step three: install a liftable metal frame under the area to be filled at the top of the mine, lay a flexible waterproof cloth on the frame and fix it to form a suspended groove at the top; deliver 1 / 2 of the volume of solid filling material to the suspended groove, extract 15%-20% of the material mass of the water gushing and spray it evenly, stir for 2-3 minutes, then stir again for 1-2 minutes at an interval of 8-10 minutes, remove the liftable frame after the material is initially set, and repeat the operation to complete the full top filling; Step four: install a detachable metal baffle in the area to be filled on the side wall to form a side groove with a bottom inclined to the water gushing area at an angle of 5°-8°; pour 2 / 3 of the volume of solid filling material into the side groove, and stir the water gushing of 12%-18% of the material mass in multiple times, supplement and compact the material after it is initially set, and remove the baffle and seal the gap after the material is solidified; Step five: maintain the humidity inside the mine ≥80% for 7-10 days, detect the density and compressive strength of the filling body to ensure that there is no cavity or crack.

[0007] Preferably, the following steps are also included: Steel frame preparation: simultaneously investigate the existing steel structure enclosing the water gushing area on the top and side wall of the mine during the survey, and supplement the steel frame on the top and side wall; Water gushing area steel frame reinforcement: after confirming that the remaining steel frame has no deformation or fracture, fix the steel frame to the stable rock layer of the cave wall, and weld and fix the steel plate baffle to the remaining steel frame; Top steel frame supplement and combination: supplement horizontal and vertical steel frames at intervals of 1-2m in the area to be filled on the top of the remaining original steel frame, fix the horizontal steel frame to the weathered rock layer below the cave wall with expansion anchor bolts with a burial depth of ≥150mm to form a grid support system; temporarily fix the liftable frame and the grid steel frame, fully mix the solid filling material with the steel frame, and finally retain the grid steel frame and the top filling body to cooperate under stress; Side wall steel frame supplement and combination: retain the original steel frame on the side wall, supplement vertical steel frames along the height direction, and supplement horizontal steel frames to be bolted to the original and vertical steel frames to form a grid system; weld and fix the metal baffle to the steel frame, fully mix the solid filling material with the steel frame, and support the steel frame and the filling body cooperatively after solidification.

[0008] Preferably, the mine solid waste is waste rock powder or tailings sand with a particle size of ≤8mm; the cementing material is a mixture of slag cement and desulfurization gypsum in a ratio of 4:1; the accelerator is calcium aluminate powder; and the binder is polyvinyl alcohol powder.

[0009] Preferably, a multifunctional stirrer is used, which is equipped with a replaceable stirring head and a 2-8 m telescopic aluminum alloy rod, the rod body is provided with a non-slip handle and a length locking device.

[0010] Compared with the prior art, the application provides a waste mine hole self-filling method, which has the following beneficial effects: 1. The method accurately surveys the mine hole parameters by unmanned aerial vehicle aerial photography combined with geological radar, and designs the groove enclosure of the water gushing area, the top suspended groove and the side wall inclined groove structure, without the need for high-altitude operation equipment and temporary support, which greatly reduces the construction risk. At the same time, it is suitable for different height and slope of small and medium-sized waste mine holes, which can effectively plug the water gushing, prevent the top floatstone from falling off and the side wall from seepage, completely eliminate the mine geological safety hidden danger, and adapt to various mine hole treatment scenes with water gushing; 2. The material is self-cured relying on the mine water gushing, avoiding the imbalance of water and material caused by additional water in traditional technology, and cooperating with multiple stirring and material supplementing and compaction process, the filling body density is ≥90%, and the compressive strength is ≥2.5MPa. If combined with the steel frame supplementing step, the grid-shaped steel frame and the filling body bear stress cooperatively, the stress of the key node of the steel frame is ≤70% of the design strength of the steel material, and the interface void ratio is ≤3%, which further improves the crack resistance and bearing capacity of the filling body, and ensures the long-term use stability; 3. The solid filling material mainly uses mine solid waste (waste stone powder, tailings sand) with a particle size of ≤8mm, which has a high proportion and realizes the resource utilization of solid waste, reduces the pollution caused by solid waste storage; without a large number of external equipment and water resource investment, the construction cost is reduced by more than 30% compared with traditional technology. At the same time, the humidity is maintained by using the natural evaporation of the water gushing in the maintenance stage, the process is closely connected, the filling efficiency is improved by 40%, the economic efficiency and ecological environmental protection requirements are considered, and the green mine treatment concept is met.

[0011] The above description is only a summary of the technical scheme of the application. In order to more clearly understand the technical means of the application and can be implemented according to the content of the specification, the following will be described in detail with the preferred embodiments of the application. The specific embodiments of the application are given in detail by the following examples. Specific embodiments

[0012] A certain waste iron mine hole is selected as the implementation object, the mine hole is a small and medium-sized roadway type mine hole, and the specific parameters are as follows: Spatial size: the mine hole height is 6m, the side wall slope is 80°, and the horizontal cross section is rectangular (4m wide x 50m long); Water gushing condition: the water gushing area is located at the bottom center of the mine hole, and the water gushing amount is stable at 3m³ / h, without concentrated water inrush point; Geological condition: the wall is mainly composed of medium weathered sandstone, and there are fine cracks (width ≤2mm) in the local side wall, and there is no obvious floatstone on the top; Existing structure: the steel frame of the original steel material surrounding the water gushing area at the top and side wall of the mine, made of Q235 steel, with a cross-sectional size of 80mmx40mmx4mm, a distribution interval of 1.5m, and some node bolts loose, without obvious deformation or fracture. Example

[0013] I. Preliminary investigation and foundation preparation: (1) Mine investigation: The combination of "drone aerial photography + geological radar" is adopted: Drone aerial photography: DJI Mavic 3 industry version drone is selected, equipped with laser radar module, to conduct three-dimensional modeling of the inside of the mine and accurately locate the water gushing area boundary (coordinates X:10m-Y:20m-Z:0m to X:12m-Y:22m-Z:0m), and confirm the water gushing amount of 3m³ / h; Geological radar detection: Sweden MALA geological radar (antenna frequency 250MHz) is used, with one measuring line every 2m along the wall, and the top height of 6m, the side wall slope of 80°, and the side wall fissure concentrated in the height range of 2-4m from the bottom are detected.

[0014] (2) Configuration of solid filling material: The following raw materials are mixed in a mass ratio, with a total configuration amount of 50m³ (satisfying the filling demand of the whole mine): Mine solid waste: waste stone powder (particle size ≤8mm, accounting for 70%, about 35m³) left by the mine is crushed by a jaw crusher and then passes through an 8mm screen to remove impurities; Cementing material: slag cement (P・S・A 42.5 grade, accounting for 18%, about 9m³) and desulfurization gypsum (industrial grade, accounting for 4.5%, about 2.25m³) are mixed in a ratio of 4:1 to ensure cementing activity; Accelerator: calcium aluminate powder (industrial grade, purity ≥90%, accounting for 5%, about 2.5m³) to improve the initial setting speed of the material; Binder: polyvinyl alcohol powder (type PVA-1799, accounting for 2.5%, about 1.25m³) to enhance the adhesion of the material to the wall.

[0015] The above raw materials are put into a JS500 type forced mixer, stirred for 3 minutes, and then transported to a sealed silo (volume 60m³ with a dehumidifying device) after uniform mixing. The moisture content of the material is monitored by the humidity sensor in the silo to ensure that the water content is stable at 4.2% (≤5%).

[0016] II. Filling of water gushing area: (1) Groove enclosure: Q235 steel plate is selected to process the baffle, and the baffle parameters are: thickness 6mm, height 70cm, single block width 1.5m, a total of 8 blocks. The baffle is spliced around the water gushing area to form a rectangular groove of 2m x 2m x 0.8m (volume 3.2m³, 1.07 times of the water gushing volume 3m³ / h, meeting the requirement of 2-3 times volume); the gap between the bottom of the baffle and the contact part of the hole bottom is sealed with quick-setting mortar (strength grade M15, initial setting time 15 minutes) to prevent water from leaking from the bottom.

[0017] (2) Material filling and water stop plug formation: 2.1m³ of solid filling material (2 / 3 of the volume of the groove) is poured into the groove, and a portable mixer (model HJ-20, power 1.5kW) is used to stir it in three times: 1.5 minutes each time, with an interval of 5 minutes, to ensure that the material and water are initially mixed; after stirring is completed, the material is left to stand for 45 minutes, and the water stop plug is gradually formed. The on-site observation shows that there is no obvious water seepage on the surface of the water stop plug, and the water gushing sealing effect meets the standard, and the remaining material (about 0.3m³) in the groove is reserved for use.

[0018] III. Filling of the top of the mine (1) Suspended groove construction: Liftable metal frame: aluminum alloy material (model 6061-T6) is selected, the cross-sectional size of the frame horizontal rod and vertical rod is 50mm x 30mm x 4mm, the length of a single frame is 3m (adapted to the width of the mine 4m, covering 3m length per section, a total of 17 sections), the frame spacing is 1.8m, and the height is adjusted to fit the top (6m height) by a manual hydraulic rod; Flexible waterproof cloth laying: 0.5mm thick PVC waterproof cloth (breaking strength 25kN / m) is selected, cut into a rectangle of 3m x 4.2m (10cm beyond the frame edge), laid on the frame, and the edge of the waterproof cloth is fixed to the wall with M8 expansion bolts (304 stainless steel) to form a single section volume of 3m x 4m x 0.5m = 6m³ "suspended groove".

[0019] (2) Material filling and solidification: Material conveying: solid filling material is conveyed to the suspended groove by a belt conveyor (belt width 500mm, conveying speed 1m / s), and 3m³ (1 / 2 of the groove volume) is poured into each section; Water gushing spraying: 0.54m³ of water gushing (18% of the material mass, material density 1.8t / m³, 3m³ of material mass 5.4t, 18% is 0.972t, water gushing density 1t / m³, corresponding to 0.972m³, actually 1m³ to ensure sufficient) is extracted from the water gushing area groove, and is uniformly sprayed to the surface of the material through a spraying pipe (hole diameter 2mm, spacing 10cm); Stirring and solidification: Stirring with a small stirring paddle (power 1 kW, telescopic rod length 6 m, straight paddle stirring head) for 2.5 minutes to ensure uniform mixing of water and material; stir again after 9 minutes interval for 1.2 minutes to promote gelation reaction; after 2 hours of standing, no obvious flow is observed on the surface of the material (initial setting state is reached), the liftable frame is removed, and the waterproof cloth is retained as a filling body protective layer; repeat the above steps to complete 17 sections of top filling, with a total filling amount of 51 m³.

[0020] Four, mine side wall filling: (1) Side groove construction: A 6mm thick Q235 steel plate is selected to process a detachable baffle, with a width of 60 cm, a height of 50 cm, and a single block weight of 15 kg, which is convenient for manual installation. Along the side wall, one baffle is arranged every 1 m, and the baffle is fixed to the wall pre-set hole (hole distance 1.1 m, buried depth 120 mm) through expansion bolts. The baffle and the wall form a "side groove" with a width of 50 cm, and the bottom of the groove is raised by a gasket to form an 8° slope (inclined to the water gushing area) to facilitate the drainage of excess water.

[0021] (2) Material filling and solidification: Material input: 0.17 m³ of solid filling material (2 / 3 of the volume) is input into each section of the side groove (length 1 m x width 0.5 m x height 0.5 m = 0.25 m³), a total of 50 m x 2 sides x 0.17 m³ = 17 m³; Water gushing drainage: The water gushing area is drained through a plastic pipe (diameter 50 mm), and 0.023 m³ (15% of the material mass) is injected into each groove, with a total of 0.17 m³ of material mass being 0.306 t, and 15% being 0.0459 t, corresponding to 0.0459 m³, and actually injecting 0.05 m³; Stirring and material supplementing: Stirring is performed twice using a handheld stirrer (with a right-angle stirring head, power 800 W), with each stirring lasting 1.5 minutes and an interval of 6 minutes. After stirring is completed, the material surface is allowed to stand for 1 hour without flow (initially coagulated), and 0.03 m³ of solid filling material is supplemented at the top of the groove and lightly compacted using a small vibrating rod (diameter 30 mm); Baffle removal and gap sealing: After standing for 2.5 hours, the material compressive strength reaches 2.8 MPa (≥2.5 MPa), and the metal baffle is gradually removed. The gap (width ≤5 mm) exposed after the baffle is removed is sealed with a putty-like mixture of the remaining solid material and a small amount of water gushing (water to material ratio 1:5), and manually compacted to ensure that the side wall is leak-free.

[0022] Five, overall maintenance and detection: (1) Maintenance control: The humidity inside the mine is maintained by natural evaporation of water inflow, and wind baffles are set at both ends of the mine to reduce air convection. Real-time monitoring is performed by humidity sensors (5 monitoring points are arranged) to ensure that the humidity is stable at 85% (≥80%) for 10 consecutive days. Daily inspection is performed during the curing period, and a fine crack (5 cm long and 0.5 mm wide) is found on the surface of the top filling body. The same material (water content increased to 20%) is used to repair and compact the crack in time.

[0023] (2) Performance testing: After curing, testing is performed according to the "Standard for Engineering Rock Mass Test Methods" (GB / T 50266-2013): Filling body density: 20 random test points are selected for testing using an ultrasonic detector (model ZBL-U520), and the average density is 93% (≥90%); Compressive strength: 10 groups of standard test specimens with a diameter of Φ50mm x 100mm are drilled, and the average compressive strength is 3.1MPa (≥2.5MPa) as tested on a pressure testing machine (model YES-2000); Appearance detection: visual observation combined with flashlight illumination, no cavities or obvious cracks are found, no water seepage is found in the side wall cracks, and the foundation filling effect meets the standard. Example

[0024] On the basis of the above foundation filling steps, a steel frame supplement process is added to further improve the strength of the filling body. The specific steps are as follows: I. Steel frame preparation: (1) Steel frame investigation and scheme determination: Through manual inspection combined with unmanned aerial photography, the distribution position (1 root of steel frame per 1.5m along the length direction on the top, 1 root of steel frame per 1.5m along the height direction on the side wall) and the integrity (only 3 node bolts are loose, no deformation) of the original steel frame are recorded. It is determined to retain all original steel frames, and the supplementary steel frames are designed according to the following parameters: Top supplementary steel frame: Q235B material, rectangular steel pipe with cross-sectional size of 100mm x 50mm x 5mm, length of 4m (adapted to the width of the mine), interval of 1.2m (0.3m apart from the original steel frame), total of 34 roots; Side wall supplementary steel frame: Q235B material, rectangular steel pipe with cross-sectional size of 80mm x 40mm x 4mm, length of 6m (adapted to the height of the mine), interval of 0.9m (0.6m apart from the original steel frame), total of 34 roots on each side, total of 68 roots.

[0025] (2) Steel frame treatment and accessory preparation: Retained steel frame treatment: use sand blasting equipment (model KH-600) to perform Sa2.5 grade rust removal on the original steel frame, remove surface rust and oil; after rust removal, brush epoxy zinc-rich primer, and after 24 hours, brush chlorinated rubber finish, to ensure corrosion protection effect; Supplementary steel frame processing: commission a steel structure factory to process supplementary steel frames according to design dimensions, and perform corrosion protection before leaving the factory; Accessory preparation: purchase hot-dipped galvanized carbon steel bolts (M12x50mm, total 500 sets), nuts, washers, M16 expansion anchors (material 304 stainless steel, tensile load capacity 18kN, total 200 sets), and M12 expansion anchors (material hot-dipped galvanized carbon steel, tensile load capacity 12kN, total 300 sets), all of which meet the GB / T 3098.1-2010 standard.

[0026] II. Steel frame reinforcement in water gushing area: (1) Steel frame inspection and reinforcement: Visual inspection: manually inspect the original steel frame one by one to confirm that there is no deformation or fracture, and only 3 node bolts are loose; Node reinforcement: tighten the loose bolts with double nuts (tighten torque 50N.m), supplement welds for 2 weakly welded nodes (weld height less than 5mm), weld height 6mm, length 50mm, use E43 welding rod for manual arc welding, and remove welding slag after welding; Hole wall fixation: add M16 expansion anchors at the weak connection between the original steel frame and the hole wall (at both ends of each steel frame), with a spacing of 600mm and an anchor depth of 160mm (embedded in the moderately weathered rock layer), and tighten with a torque wrench (torque 80N.m) to ensure firm connection between the steel frame and the hole wall.

[0027] (2) Fixation of baffle and steel frame: Weld the surrounding baffle in the water gushing area to the original steel frame, with the welding position being the top of the baffle and the lower flange of the steel frame, the weld length being 100mm per position, and the spacing being 300mm, to ensure that the baffle and steel frame work together to resist deformation of the groove.

[0028] III. Supplementary and combination of top steel frame: (1) Construction of grid-shaped steel frame support system: Horizontal steel frame installation: lay the supplementary Q235B I-shaped steel (model I10, length 4m) along the length direction of the mine hole at an interval of 1.2m, and fix the two ends to the hole wall through M16 expansion anchors (anchor depth 150mm, embedded in the moderately weathered rock layer), and add spring washers between the expansion anchors and the steel frame to prevent loosening; Longitudinal steel frame connection: The additional Q235B rectangular steel pipe (100mm x 50mm x 5mm, length 3m) is connected vertically with the transverse steel frame, and is fixed with M12 bolts (2 sets of bolts per node), forming a 1.2m x 3m grid-shaped support system, which forms a whole with the original steel frame.

[0029] (2) Filling body and steel frame combination: Material contact control: When delivering solid filling material to the suspended groove, ensure that the material fills the gap between the steel frame grid, and use the stirring paddle to go deep below the steel frame during stirring to avoid voids; Solidification coordination: After the initial setting of the material, remove the liftable frame, leaving the grid-shaped steel frame, and the filling body closely adheres to the steel frame, forming a "steel frame-filling body" coordinated stress structure, with the steel frame bearing part of the top load and reducing the stress on the filling body.

[0030] Four, side wall steel frame supplement and combination: (1) Grid-shaped steel frame system construction: Vertical steel frame installation: The additional Q235B rectangular steel pipe (80mm x 40mm x 4mm, length 6m) is arranged along the height direction of the side wall at intervals of 0.9m, and is fixed to the hole wall by M12 expansion anchor bolts (hole distance 1.1m, buried depth 120mm), with a flat washer added between the anchor bolt and the steel frame; Transverse steel frame connection: The additional Q235B rectangular steel pipe (80mm x 40mm x 4mm, length 4m) is connected vertically with the vertical steel frame and the original steel frame, and is fixed with M12 bolts (2 sets of bolts per node), forming a 0.9m x 1.1m grid-shaped system.

[0031] (2) Filling body and steel frame combination: Material mixing: When pouring solid filling material into the side groove, ensure that the material wraps around the steel frame, and use a right-angle stirring head to rotate around the steel frame during stirring to avoid gaps between the steel frame and the material; Gap sealing: After the material solidifies, remove the baffle and inject epoxy resin slurry (type E-44, compressive strength 35MPa) into the small gaps (width ≤1mm) between the steel frame and the filling body, using a low-pressure grouting machine (pressure 0.2MPa) to ensure the tightness of the joint surface.

[0032] Five, steel frame-filling body coordination performance test: On the basis of the foundation filling test, the following test items are added: Steel frame key node stress: Use stress sensors (type BF120-3AA) to paste on the steel frame nodes, a total of 10 measuring points, to detect the maximum stress of 55MPa (Q235 steel design strength 215MPa, ≤70% design strength, meeting the requirements); The compactness of the joint surface: the joint surface of the steel frame and the filling body is detected by an ultrasonic detector, 30 measuring points are randomly selected, the joint surface void ratio is 2.2% (≤3%, meeting the requirement), and there is no obvious void.

[0033] The above is only a preferred embodiment of the present application, and does not limit the present application in any form; any ordinary skilled person in the industry can easily implement the present application according to the description and the above; however, any slight change, modification and evolution of the equivalent changes made by the skilled person in the professional field without departing from the technical scheme of the present application, using the above disclosed technical content, are equivalent embodiments of the present application; at the same time, any equivalent change, modification and evolution of the above embodiments according to the essence of the present application are still within the protection scope of the technical scheme of the present application.

Claims

1. A method for self-filling abandoned mine shafts, characterized in that: Includes the following steps: Step 1: Use drone aerial photography combined with ground-penetrating radar to obtain the location, volume, top height, sidewall slope, and fissure distribution of the water inflow area in the mine; mix mine solid waste, cementing materials, quick-setting agents, and binders according to the mass ratio to form a solid filling material, and seal and store it after thorough mixing. Step 2: Enclose the water inflow area with steel plate baffles to form a groove with a volume of 2-3 times the water inflow. Seal the gaps at the bottom of the baffles with quick-setting mortar. Put solid filling material into the groove, filling it with 2 / 3 of its volume. Stir it multiple times with a portable mixer, with an interval of 4-8 minutes between each stirring. Let it stand for 30-60 minutes to form a water stop plug and seal the water inflow point. Keep the remaining solid material in the groove for later use. Step 3: Install a liftable metal frame below the area to be filled at the top of the mine shaft. Lay a flexible waterproof cloth on the frame and fix it to form a suspended groove at the top. Convey solid filling material to the suspended groove, filling it to 1 / 2 of its volume. Draw water to make up 15%-20% of the material mass and spray it evenly. Stir for 2-3 minutes, then stir again for 1-2 minutes after an interval of 8-10 minutes. After the material has initially solidified, remove the liftable frame. Repeat the operation to complete the filling of the entire top. Step 4: Install a removable metal baffle on the side wall to be filled, forming a side groove with the bottom inclined at 5°-8° towards the water inflow area; put solid filling material into the side groove, filling it with 2 / 3 of its volume; drain water accounting for 12%-18% of the material mass and stir it repeatedly; after the material has initially solidified, add more material and compact it; after the material has solidified, remove the baffle and seal the gaps. Step 5: Maintain the humidity inside the mine shaft at ≥80% for 7-10 days, and test the density and compressive strength of the filling material to ensure there are no voids or cracks.

2. The self-filling method for abandoned mine shafts according to claim 1, characterized in that: It also includes the following steps: Steel frame preparation: During the exploration, the existing steel structures enclosing the water inrush area on the top and side walls of the mine should be checked simultaneously, and steel frames should be added to both the top and side walls; Reinforcement of steel frame in water inrush area: After confirming that the remaining steel frame is free from deformation and breakage, fix the steel frame to the stable rock layer of the tunnel wall, and weld the steel plate baffle to the remaining steel frame; Top steel frame supplementation and integration: The original top steel frame is retained, and horizontal and vertical steel frames are added at intervals of 1-2m in the area to be filled. The horizontal steel frames are fixed to the weathered rock layer in the tunnel wall below the wall using expansion anchors with a burial depth of ≥150mm, forming a grid-like support system. The liftable frame is temporarily fixed to the grid-like steel frame, and the solid filling material is in full contact with the steel frame. Finally, the grid-like steel frame and the top filling body are retained to share the load. Side wall steel frame supplementation and integration: The original side wall steel frame is retained, and vertical steel frames are added along the height direction. The horizontally added steel frames are bolted to the original and vertical steel frames to form a grid system. Metal baffles are welded and fixed to the steel frame. Solid filling material is fully mixed with the steel frame. After curing, the steel frame and the filling material work together to support each other.

3. A self-filling method for abandoned mine shafts according to claim 1 or 2, characterized in that: The solid waste from the mine is waste rock powder or tailings sand with a particle size ≤ 8mm; the cementing material is a mixture of slag cement and desulfurized gypsum in a 4:1 ratio; the quick-setting agent is calcium aluminate powder; and the binder is polyvinyl alcohol powder.

4. A self-filling method for abandoned mine shafts according to claim 1 or 2, characterized in that: It features a multi-functional mixer with replaceable mixing heads and a 2-8m telescopic aluminum alloy rod, with a non-slip grip and length locking device on the rod.