A method for collaborative loss reduction mining by fluidized filling disposal in coal-based solid waste caving areas

Abstract

The present invention belongs to the technical field of green mining in coal mines, and discloses a method for fluidized filling disposal and coordinated loss reduction mining in coal-based solid waste caving areas. By matching the volume of pre-prepared coal-based solid waste filling materials with the positive equilibrium relationship of the filling space in the caving area, a filling space of appropriate size is screened out; secondly, according to the position of the working face and the arch foot of the semi-arch structure, the filling operation is divided into multiple filling windows; finally, a backward fluidized filling method is used to complete the filling of each window period in sequence. The use of this method improves the efficiency of solid waste source disposal, reduces the cost of material preparation, optimizes the utilization rate of spatial resources in the caving area, and strengthens the synergy between waste storage and loss reduction mining, thereby effectively alleviating the ecological environment damage caused by ground solid waste storage and underground goaf.

Description

Technical Field

[0001] The present invention belongs to the technical field of green coal mining, and specifically relates to a collaborative loss reduction mining method for fluidized filling disposal in coal-based solid waste caving areas. Background Art

[0002] In the field of coal resource development and utilization, problems such as large-scale surface solid waste storage and the formation of large underground goafs are seriously exacerbating ecological damage in mining areas. Currently, the contradiction between the demand for coal-based solid waste disposal and the carrying capacity of the surface ecological environment is becoming increasingly acute, and the marginal benefits of using surface storage space resources are continuously decreasing. At the same time, rock movement caused by coal mining has led to a series of safety and environmental issues. The continuous deformation and damage of uncompacted spaces formed after the natural collapse of the roof in the caving area poses a significant threat to mining safety and surface ecological protection.

[0003] Currently, green mining and waste-free mine construction have become inevitable trends in the development of the industry. Green and efficient disposal of coal-based solid waste and mitigation of mining damage are common challenges faced by coal companies. Fluidized filling technology for coal-based solid waste caving areas has become an important solid waste disposal and loss reduction mining technology, but there are many problems in its actual application. After underground coal seams are mined, the dynamic compaction and continuous changes in the void structure of the caving area affect the safety and stability of the mine filling system, resulting in low efficiency in the source disposal of coal-based solid waste, high costs for preparing solid waste filling materials, insufficient utilization of spatial resources in the caving area, and poor coordination between waste storage and loss reduction.

[0004] In summary, existing technologies are unable to achieve green and efficient disposal of coal-based solid waste at the source and coordinated loss-reducing mining, and it is difficult to effectively solve the problem of large-scale solid waste storage on the ground and the formation of large underground goafs, which exacerbate the damage to the ecological environment in mining areas. Summary of the Invention

[0005] The present invention provides a method for collaborative loss reduction mining by fluidized filling disposal in coal-based solid waste caving areas. This method realizes green and efficient disposal of coal-based solid waste at the source and collaborative loss reduction mining, effectively solving the problem of large-scale solid waste storage on the ground and the formation of large underground goafs, which aggravate the damage to the ecological environment in mining areas.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for collaborative loss reduction mining by fluidized filling disposal in coal-based solid waste caving areas, comprising:

[0008] Based on the positive equilibrium relationship between the volume of the filling material and the filling space of the caving area, the volume of the filling material is matched with the filling space of the caving area to screen out the filling space of the caving area that meets the conditions; the filling material is pre-prepared based on the coal-based solid waste to be filled and disposed of in the mine and its surrounding areas; the filling space of the caving area is calculated based on the coal seam mined volume, the surface subsidence volume, and the unloading expansion volume of the fracture zone and the curved subsidence zone;

[0009] Based on the screened working surface of the caving area filling space and the position of the arch foot of the semi-arch structure, the filling operation of the caving area filling space is divided into multiple filling windows;

[0010] According to the sequence of the filling windows, the backward fluidized filling method is used to carry out the filling operation of each filling window in turn until the filling operation corresponding to the last filling window is completed.

[0011] Furthermore, the matching of the volume of the filling material with the filling space of the caving area based on the positive equilibrium relationship between the volume of the filling material and the filling space of the caving area includes:

[0012] According to the positive equilibrium relationship between the volume of the filling material and the filling space of the caving area, the volume of the filling material is matched with the filling space of the caving area;

[0013] The positive equilibrium relationship is specifically expressed as follows:

[0014]

[0015] Where, V c Indicates the filling space of the caving area; V f Indicates the volume of filling material;

[0016] The calculation formula for the filling space of the caving area is as follows:

[0017]

[0018] Where, V 1 represents the volume of coal seam mined; V 2 represents the volume of surface subsidence; V 3 represents the unloading expansion volume of the fracture zone and the bending subsidence zone; k It represents the space utilization coefficient of the caving area, which is obtained based on the filling test.

[0019] Furthermore, based on the screened working surface of the caving area filling space and the position of the arch foot of the semi-arch structure, the filling operation of the caving area filling space is divided into multiple filling windows, including:

[0020] Obtaining the positions of the working face and the arch foot of the semi-arch structure in the filling space of the caving area; the semi-arch structure is an arch-shaped stress partition formed by the deflection of the principal stress of the overlying bedrock in the mining area caused by the periodic breaking of the roof during the mining process of the working face;

[0021] According to the position of the working face of the filling space in the caving area and the arch foot of the semi-arch structure, the mining time of the filling operation of the filling space in the caving area is obtained, and the mining time is divided into multiple filling windows.

[0022] Furthermore, before dividing the filling operation of the caving area filling space into a plurality of filling windows based on the working surface of the caving area filling space obtained by screening and the position of the arch foot of the semi-arch structure, the method further includes:

[0023] A charging port is pre-arranged at the boundary position of the filling space of the caving area corresponding to the arch foot of the semi-arch structure; the charging port includes multiple groups of filling boreholes and filling pipes; the filling boreholes are distributed in the coal pillars along the goaf tunnel and the caving area, and the filling pipes are reserved and arranged in the tail tunnel of the working face.

[0024] Furthermore, before dividing the filling operation of the caving area filling space into a plurality of filling windows based on the working surface of the caving area filling space obtained by screening and the position of the arch foot of the semi-arch structure, the method further includes:

[0025] Arrange the filling system of the caving area, including:

[0026] Connect the filling station with the filling pipeline, and introduce the filling pipeline into the underground main tunnel and gob-side tunnel in sequence;

[0027] Connect the filling pipeline introduced into the gob-side tunnel to the filling port through a branch pipe, or after introducing the branch pipe into the tail tunnel of the working face, connect the branch pipe to the reserved filling pipe;

[0028] Each branch pipe is provided with a material distribution valve and an online detector, and the online detector is used for online monitoring of flow, pressure and viscosity.

[0029] Furthermore, before performing the filling operation in each filling window period in sequence by adopting the backward fluidized filling method according to the sequence of the filling windows, the method further includes:

[0030] Coal-based solid waste is used to pre-prepare filling materials, and the filling materials are controllable low-strength materials; wherein the preparation process of the controllable low-strength materials is as follows:

[0031] Crushing coal-based solid waste raw materials into graded particles;

[0032] The graded particles are uniformly mixed with the cementitious material and the water reducing agent according to a preset ratio, and after mixing, mine water is added to prepare a controllable low-strength material;

[0033] Wherein, the coal-based solid waste raw material is coal gangue or a combination of coal gangue and at least one of fly ash, slag, gasified slag, and desulfurized gypsum;

[0034] The graded particles are continuously graded particles with a particle size of less than 5 mm, and the mass of particles with a particle size of less than 0.3 mm accounts for at least 15% of the total mass of the continuously graded particles.

[0035] Furthermore, the coal-based solid waste raw material includes coal gangue, and the mass of the coal gangue accounts for at least 60% of the total mass of the coal-based solid waste raw material.

[0036] Furthermore, the mass concentration of the controllable low-strength material is 72%~77%, the slump is ≥220 mm, and the mass ratio of the water reducer to the cementitious material is 0.3%~0.6%; when the controllable low-strength material is added with a low-activity cementitious material, the mass of the cementitious material is the total mass of the cement and the low-activity cementitious material; the low-activity cementitious material is at least one of fly ash, slag powder and slag powder.

[0037] Furthermore, the method of sequentially performing the filling operation of each filling window period by adopting a backward fluidized filling method until the filling operation corresponding to the last filling window period is completed includes:

[0038] Based on the calculated filling rate of the caving area and the subsidence of the loss-reduction control layer, the effect of fluidized filling and waste storage and coordinated loss-reduction mining in the caving area is characterized to achieve effect evaluation.

[0039] Furthermore, before characterizing the effect of fluidized filling, storage and wastewater synergistic loss reduction mining in the caving area based on the calculated filling rate of the caving area and the subsidence of the loss reduction control layer, the method further includes:

[0040] Based on the volume of the filling material filled into the caving area and the filling space of the caving area, the filling rate of the caving area is calculated. The specific formula is as follows:

[0041]

[0042] Where, η ct is the filling rate of the caving area; V ct is the volume of filling material filled into the caving area; V 1 represents the volume of coal seam mined; V 2 represents the volume of surface subsidence; V 3 represents the unloading expansion volume of the fracture zone and the bending subsidence zone; k Indicates the space utilization coefficient of the caving area;

[0043] The subsidence of the damage reduction control layer before filling, the compaction rate of the composite filling body, the expansion coefficient of the caving rock mass, and the total thickness of the caving zone rock layer are used to calculate the subsidence of the damage reduction control layer. The specific formula is as follows:

[0044]

[0045] Where, w j To reduce the subsidence of the control layer; w z It is the subsidence of the loss-control layer before filling; η c is the compaction rate of composite filling; K p is the expansion coefficient of the falling rock mass; ∑ h It is the total thickness of rock strata in the caving zone.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The present invention provides a method for fluidized filling disposal of coal-based solid waste caving areas in coordination with loss reduction mining. This method first selects a filling space of appropriate size by matching the volume of pre-prepared coal-based solid waste filling materials with the positive equilibrium relationship of the filling space in the caving area; secondly, the filling operation is divided into multiple filling windows according to the position of the working face and the arch foot of the semi-arch structure; finally, the filling of each window is completed in sequence by using a backward fluidized filling method. In this method, the positive volume balance matching ensures the dynamic balance between the material and the space, reducing the impact of the void changes in the caving area on the system; the window period division utilizes the mechanical support advantage of the semi-arch structure to provide a stable filling environment; the backward filling simulates the natural compaction process of the caving area to maintain the continuity and uniformity of the operation. This method improves the efficiency of solid waste source disposal, reduces the cost of material preparation, optimizes the utilization rate of spatial resources in the caving area, and strengthens the synergy between waste storage and loss reduction mining, thereby effectively alleviating the ecological and environmental damage caused by ground solid waste storage and underground goaf.

[0048] In the present invention, preferably, a dynamic matching model is constructed based on the accurate calculation of the coal seam mining volume, the surface subsidence volume and the unloading expansion volume of the fracture zone and the curved subsidence zone, combined with the space utilization coefficient determined by the filling test. This can achieve scientific adaptation of the volume of the filling material and the filling space, thereby improving the economic and environmental benefits of the filling effect.

[0049] In the present invention, preferably, the filling window period is dynamically divided according to the position of the working face and the arch foot of the semi-arch structure, so that the filling operation is synchronized with the dynamic compaction process of the caving area, avoiding uneven filling due to changes in the void structure, and improving the slag storage capacity of the caving area and the compaction mechanical properties of the caving rock mass.

[0050] In the present invention, preferably, a filling port is preset at the boundary of the caving area corresponding to the arch foot of the semi-arch structure, and precise filling is achieved through multiple sets of drilling holes and filling pipelines, thereby reducing the influence of time and space interference in mining and filling, improving filling efficiency, avoiding construction risks, and ensuring the safety of workers.

[0051] In the present invention, preferably, a downhole filling pipe network and branch pipe system are constructed, equipped with a material distribution valve and an online detector to achieve real-time monitoring and dynamic regulation of flow, pressure, and viscosity, ensure the continuity and uniformity of the filling process, and improve the filling quality.

[0052] In the present invention, preferably, by crushing and grading the coal-based solid waste raw materials, combined with the optimized ratio of cementitious materials and additives, a controllable low-strength material with good fluidity is prepared, thereby reducing the cost of solid waste treatment and improving the engineering performance and environmental benefits of the filling material.

[0053] In the present invention, preferably, a minimum proportion of coal gangue in coal-based solid waste raw materials is specified to ensure the aggregate stability of controllable low-strength materials, promote large-scale resource utilization of coal gangue, and reduce the pressure of solid waste storage.

[0054] In the present invention, preferably, by adding low-activity cementitious materials such as fly ash and slag powder, the cementitious system of the controllable low-strength material is optimized, the cement dosage is reduced, the carbon emission is reduced, and the stability of the caving zone is improved.

[0055] In the present invention, preferably, a quantitative evaluation system for the filling rate of the caving area and the subsidence of the loss control layer is established to achieve accurate evaluation of the filling effect, provide a scientific basis for the optimization of the filling process and the adjustment of the mining plan, and promote the standardization and normalization of the fluidized filling technology in the caving area of coal-based solid waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 A flow chart of a method for collaborative loss reduction mining by fluidized filling and disposal of coal-based solid waste caving areas provided by an embodiment of the present invention;

[0057] Figure 2 A schematic diagram of the structure involved in pre-harvest spatial collaboration provided by an embodiment of the present invention;

[0058] Figure 3 A schematic diagram of the structure involved in the collaborative acquisition and filling process provided by an embodiment of the present invention;

[0059] Figure 4 The present invention provides a flow chart of a method for collaborative loss reduction mining by fluidized filling disposal in coal-based solid waste caving areas.

[0060] Reference numerals:

[0061] 1. Coal seam mined volume; 2. Surface subsidence volume; 3. Unloading expansion volume of fracture zone and curved subsidence zone; 4. Semi-arch structure; 5. Falling gangue; 6. Arch foot; 7. Working face; 8. Falling area; 9. Gob-side tunnel; 10. Coal pillar; 11. Backfilling borehole; 12. Backfilling pipe; 13. Backfilling station; 14. Backfilling main pipe; 15. Branch pipe; 16. Online detector; 17. Underground main tunnel; 18. Coal-based solid waste raw materials; 19. Crushing device; 20. Preparation bin; 21. Mine water; 22. Composite backfill body; 23. Damage control layer. DETAILED DESCRIPTION

[0062] The technical terms involved in this invention are explained as follows:

[0063] CLSM: The full name is Controlled Low-Strength Material, which refers to coal-based solid waste controlled low-strength material. It refers to a filling material with controllable low-strength characteristics made by using coal-based solid waste (such as coal gangue, fly ash, etc.) as the main raw material, adding appropriate amounts of cementitious materials, mine water and admixtures, and mixing them according to preset proportions.

[0064] Coal-based solid waste: It is solid waste generated during coal mining and processing. Its large-scale accumulation not only occupies land, but also damages the surface ecological environment.

[0065] The embodiment provides a method for collaborative loss reduction mining of fluidized filling disposal in coal-based solid waste caving areas. This method is based on the demand for coal-based solid waste disposal in and around the mine and the dynamic evolution law of the mine caving area, and sequentially forms a pre-mining space coordination-mining and filling process coordination-waste storage and loss reduction coordination system. During the dynamic compaction process of the coal seam caving area, the CLSM caving area fluidized filling is safely implemented through the filling system within a determined filling window period, thereby filling and cementing the non-sufficient compaction space in the caving area, modifying and strengthening the compaction mechanical properties of the caving rock mass, and improving the stability of the caving area, and finally realizing green and efficient disposal of coal-based solid waste at the source and collaborative loss reduction mining, such as Figure 4 As shown, the method includes:

[0066] Based on the positive equilibrium relationship between the volume of the filling material and the filling space of the caving area, the volume of the filling material is matched with the filling space of the caving area to screen out the filling space of the caving area that meets the conditions; the filling material is pre-prepared based on the coal-based solid waste to be filled and disposed of in the mine and its surrounding areas; the filling space of the caving area is calculated based on the coal seam mined volume, the surface subsidence volume, and the unloading expansion volume of the fracture zone and the curved subsidence zone;

[0067] Based on the screened working surface 7 of the caving area filling space and the position of the arch foot 6 of the semi-arch structure, the filling operation of the caving area filling space is divided into multiple filling windows;

[0068] According to the sequence of the filling windows, the backward fluidized filling method is used to carry out the filling operation of each filling window in turn until the filling operation corresponding to the last filling window is completed.

[0069] The optimization method provided by this embodiment is further described below with reference to the accompanying drawings:

[0070] like Figure 1 As shown, this embodiment provides a method for collaborative loss reduction mining using fluidized filling disposal in coal-based solid waste caving areas. This method includes three processes: pre-mining spatial coordination, mining and filling process coordination, and waste storage and loss reduction coordination. Based on the description of the embodiment, combined with the engineering geological mining conditions of a coal mine, a specific implementation description is provided.

[0071] In this embodiment, a working face 7 of a coal mine is being mined. For the caving area in the mining process of the working face 7, the fluidized filling and disposal collaborative loss reduction mining method of the coal-based solid waste caving area is implemented.

[0072] S1. First, carry out the pre-harvest spatial collaboration process.

[0073] like Figure 2 As shown, in this embodiment, the types, properties, annual fixed emissions and disposal status of coal-based solid waste discharged by the mine and surrounding industrial and mining enterprises for three consecutive years are investigated and counted, the production plan and the upper limit of solid waste increase in the next five years are estimated, and the final solid waste disposal demand is determined; based on the disposal demand of coal-based solid waste in the mine and surrounding areas, combined with the characteristics of the filling conditions, the CLSM basic formula is selected and the volume of the filling material is calculated V f ; Coordinate the layout of the amount of coal-based solid waste that needs to be filled and disposed of each year and the space in the caving area that meets the requirements of fluidized filling to ensure the volume of preparation, pumping and filling materials V f Filling space with the falling area V c Positive balance means matching the volume of the filling material with the filling space of the caving area, and screening the filling space of the caving area that meets the conditions; the specific conditions that need to be met are as follows:

[0074]

[0075] In the formula, the filling space of the caving area is in a dynamic state as the working face 7 is mined. The coal seam mined volume 1 (given by V 1), surface subsidence volume 2 (represented by V 2), the unloading expansion volume of the fracture zone and the bending subsidence zone 3 (represented by V 3) and the space utilization coefficient of the caving area k Decide.

[0076] The specific calculation expression is ;

[0077] Where, the space utilization coefficient of the caving area is k It comprehensively reflects the difficulty of fluidized filling and waste storage in the caving area under different geological mining conditions and is determined based on filling tests.

[0078] At this point, the filling space in the caving area that meets the conditions is screened out.

[0079] It should be noted that: in this embodiment, the filling space of the caving area is calculated based on the coal seam production volume, the surface subsidence volume and the unloading expansion volume of the fracture zone and the curved subsidence zone; while the current industry mostly uses the elastic thin plate theory and the key layer theory to study the subsidence of the overlying rock strata in the goaf, and on the basis of the key layer sinking trajectory, indirectly equates it with residual crushing, detachment height, superimposed goaf height, etc. to approximate the expression of the filling space of the caving area, which has certain limitations; this embodiment adopts the method of calculating the filling space of the caving area by the coal seam production volume, the surface subsidence volume and the unloading expansion volume of the fracture zone and the curved subsidence zone, avoiding the above-mentioned limitation of dividing the filling area according to the maximum subsidence of the slurry-controlled rock group and empirical parameters, and then calculating the filling space of each area in segments, which can greatly reduce the deviation between the result and the actual situation, and increase the accuracy and practicality of the calculation.

[0080] In this embodiment, based on the positions of the working face 7 of the filling space of the caving area and the arch foot 6 of the semi-arch structure obtained by screening, the filling operation of the filling space of the caving area is divided into multiple filling window periods; wherein, the semi-arch structure is an arch stress partition formed when the main stress of the overlying bedrock of the mining area is deflected by the periodic fracture of the roof during the mining process of the working face. This arch stress partition has a certain thickness and is located on the upper part of the fractured arch. It is a bedrock stress arch structure with an arch-like appearance, and is also a bearing structure to ensure efficient filling of the caving area; adopting this method can enhance the important influence of the semi-arch structure on the dynamic compaction of the caving area and the continuous evolution of the voids, and thus scientifically guide the division of the filling space and efficient filling of the caving area.

[0081] S2. Conduct collaborative process of acquisition and filling.

[0082] Combine Figure 2 、 Figure 3 As shown, based on the formation and evolution characteristics of the semi-arch structure 4 above the working face 7, its supporting role is fully utilized, and the characteristics of the low density and large gaps of the caving waste rock 5 below it are fully utilized. Within the determined filling window period, the CLSM caving area is fluidized and filled through the filling system. The specific steps are as follows:

[0083] S21. Determining the filling window: Based on the stress monitoring data of the caving area of the adjacent working face 7, the position of the arch foot 6 of the upper semi-arch structure 4 during the mining process of the working face 7 can be determined. The mining time from the position of the arch foot 6 to the current position of the working face 7 is divided into the first, second, and third periods.n A filling window period is set, and a charging port connected to the caving area 8 is pre-arranged at the boundary position of the arch foot 6 corresponding to the caving area 8. The charging port consists of multiple groups of filling drill holes 11 evenly arranged in the coal pillar 10 between the gob-side tunnel 9 and the caving area 8, and a filling pipe 12 reserved in the tail tunnel.

[0084] S22. Filling System Layout: The filling system consists of a filling station 13, a filling main 14, branch pipes 15, a material distribution valve, and an online detector 16 for measuring flow, pressure, and viscosity. Filling station 13 connects filling main 14 to the underground main tunnel 17, then into the gob-side tunnel 9. From there, several branch pipes 15 connect to the filling port, or to the tail tunnel of the working face 7, where they connect to the reserved filling pipe 12. Each branch pipe 15 is equipped with a set of material distribution valves and an online detector 16.

[0085] S23. CLSM Preparation: Coal-based solid waste raw material 18 is crushed by a crushing device 19 until the particle size distribution requirements are met. It is then stored in a stock bin 20 with cement and a water reducer. After uniform mixing according to the designed ratio, mine water 21 is added to prepare CLSM. CLSM has a mass concentration of 72% to 77%, a slump of ≥220 mm, a gangue content of ≥60%, and a water reducer to cementitious material mass ratio of 0.3% to 0.6%. In this embodiment, the flowability of the CLSM is adjusted by combining the gangue particle size distribution with the water reducer. Its flowability must meet the minimum pumping requirements and is monitored in real time by an online detector 16. The water reducer can also use other additives, including suspending agents, stabilizers, thickeners, and accelerators.

[0086] Exemplarily, in S23, the coal-based solid waste raw material is coal gangue or a combination of coal gangue and at least one of fly ash, slag, gasification slag, and desulfurization gypsum, wherein the coal-based solid waste raw material 18 must be crushed into continuous graded particles with a particle size of less than 5 mm, wherein the mass of particles with a particle size of less than 0.3 mm accounts for at least 15% of the total mass of the continuously graded particles, which is conducive to increasing the cohesion of CLSM.

[0087] It should be noted that the execution order of steps S22 and S23 can also be performed before S21, because steps S22 and S23 are pre-execution steps and can be completed before the formal implementation of the filling operation.

[0088] S24, fluidized filling: by controlling the opening sequence and opening time of the distribution valves on each branch pipe 15, the backward fluidized filling of the caving area is realized. At the same time, the prepared CLSM is safely and smoothly filled into the filling space of the caving area during each filling window. The filling speed should be adapted to the mining speed of the working face 7, that is, by controlling the filling flow rate, the diffusion speed of the CLSM in the filling space is made consistent with the mining speed of the working face 7.

[0089] S25. After the filling operation of the current filling window period is completed, the fluidized filling operation of the next filling window period is repeated until the filling of all the caving areas 8 is completed.

[0090] For example, in S23, if low-activity cementitious materials such as fly ash, slag powder, and slag powder are added to the CLSM, the mass of the cementitious materials is the total mass of the cement and the low-activity cementitious materials.

[0091] As a preferred solution for this embodiment, CLSM preparation involves the following: coal-based solid waste material 18 is crushed by a crushing device 19 to meet the required particle size distribution. It is then mixed with cement and a water reducer and stored separately in a stock bin 20. After uniform mixing according to the designed ratio, mine water 21 is added to prepare CLSM. CLSM has a mass concentration of 77%, a slump of 220 mm, a gangue content of 67%, and a water reducer to cementitious material mass ratio of 0.3%. In this embodiment, the flowability of the CLSM is adjusted by combining the gangue particle size distribution with the water reducer. Its flowability must meet minimum pumping requirements and is monitored in real time by an online detector 16.

[0092] The coal-based solid waste raw material 18 is coal gangue, wherein the coal-based solid waste raw material 18 must be crushed into continuously graded particles with a particle size of less than 5 mm, wherein the mass of particles with a particle size of less than 0.3 mm accounts for 15% of the total mass of the continuously graded particles.

[0093] As another preferred embodiment of this embodiment, CLSM preparation: Coal-based solid waste material 18 is crushed by a crushing device 19 to meet the particle size distribution requirements. It is then mixed with cement and a water reducer and stored separately in a stock bin 20. After being evenly mixed according to the designed ratio, mine water 21 is added to prepare CLSM. CLSM has a mass concentration of 75%, a slump of 240 mm, a gangue content of 65%, and a water reducer to cementitious material mass ratio of 0.3%. In this embodiment, the flowability of the CLSM is adjusted by combining the gangue particle size distribution with the water reducer. Its flowability must meet the minimum pumping requirements and is monitored in real time by an online detector 16.

[0094] The coal-based solid waste raw materials 18 are coal gangue and fly ash. After crushing, the coal-based solid waste raw materials 18 must be continuously graded particles with a particle size of less than 5 mm, and the mass of particles with a particle size of less than 0.3 mm accounts for 18% of the total mass of the continuously graded particles.

[0095] As another preferred embodiment of this embodiment, CLSM preparation: Coal-based solid waste material 18 is crushed by a crushing device 19 to meet the particle size distribution requirements. It is then mixed with cement and a water reducer and stored separately in a stock bin 20. After being evenly mixed according to the designed ratio, mine water 21 is added to prepare CLSM. CLSM has a mass concentration of 75%, a slump of 260 mm, a gangue content of 63%, and a water reducer to cementitious material mass ratio of 0.4%. In this embodiment, the flowability of the CLSM is adjusted by combining the gangue particle size distribution with the water reducer. Its flowability must meet the minimum pumping requirements and is monitored in real time by an online detector 16.

[0096] The coal-based solid waste raw materials 18 are coal gangue, fly ash and slag. After crushing, the coal-based solid waste raw materials 18 must be continuously graded particles with a particle size of less than 5 mm, and the mass of particles with a particle size of less than 0.3 mm accounts for 18% of the total mass of the continuously graded particles.

[0097] As another preferred embodiment of this embodiment, CLSM preparation: Coal-based solid waste material 18 is crushed by a crushing device 19 to meet the particle size distribution requirements. It is then stored in a stock bin 20 with cement and a water reducer. After uniform mixing according to the designed ratio, mine water 21 is added to prepare CLSM. CLSM has a mass concentration of 73%, a slump of 260 mm, a gangue content of 60%, and a water reducer to cementitious material mass ratio of 0.4%. In this embodiment, the flowability of the CLSM is adjusted by combining the gangue particle size distribution with the water reducer. Its flowability must meet the minimum pumping requirements and is monitored in real time by an online detector 16.

[0098] The coal-based solid waste raw materials 18 are coal gangue, fly ash, gasified slag and desulfurized gypsum. After crushing, the coal-based solid waste raw materials 18 must be continuously graded particles with a particle size of less than 5 mm, and the mass of particles with a particle size of less than 0.3 mm accounts for at least 18% of the total mass of the continuously graded particles.

[0099] As another preferred embodiment of this embodiment, CLSM preparation: Coal-based solid waste material 18 is crushed by a crushing device 19 to meet the particle size distribution requirements. It is then stored in a stock bin 20 with cement and a water reducer. After uniform mixing according to the designed ratio, mine water 21 is added to prepare CLSM. CLSM has a mass concentration of 72%, a slump of 270 mm, a gangue content of 60%, and a water reducer to cementitious material mass ratio of 0.6%. In this embodiment, the flowability of the CLSM is adjusted by combining the gangue particle size distribution with the water reducer. Its flowability must meet the minimum pumping requirements and is monitored in real time by an online detector 16.

[0100] The coal-based solid waste raw materials 18 are coal gangue, fly ash, slag, gasification slag and desulfurization gypsum. After crushing, the coal-based solid waste raw materials 18 must be continuously graded particles with a particle size of less than 5 mm, among which the mass of particles with a particle size of less than 0.3 mm accounts for 20% of the total mass of the continuously graded particles.

[0101] S3. Carry out the collaborative process of storage, waste and loss reduction.

[0102] In this process, the filling rate of the caving area is η ct and the subsidence of the damage control layer w j Characterize the effect of fluidized filling and waste storage in caving area to reduce losses. Figure 3 As shown in the figure, the composite filling body 22 is a new pressure-bearing structure formed by the cementation and solidification of the broken rock mass in the caving area and the filled CLSM; the damage control layer 23 is a low-level key layer located at the bottom of the fracture zone and directly connected to the regular collapse zone after the caving area is formed. The damage control layer 23 is in direct contact with the composite filling body 22, and the two are closely connected. and the subsidence of the damage control layer The calculation expression is as follows:

[0103]

[0104]

[0105] Where, V ct is the CLSM volume filled into the caving area; w z The amount of subsidence of the loss-control layer before filling can be obtained through on-site observation; η c The compaction rate of the composite filling body is used to reflect the final compaction state of the caving area after filling. The compaction rate of the composite filling body is related to the filling rate. η ct The relationship is obtained by the compaction deformation experiment of the composite filling body 22; K p is the expansion coefficient of the falling rock mass; ∑ h It is the total thickness of rock strata in the caving zone.

[0106] As another preferred solution of this embodiment, under the premise of clarifying the subsidence index of the damage reduction control layer 23, the subsidence amount of the damage reduction control layer can be w j Feedback design of composite filling body compaction rate η c Then, the filling rate of the caving area was tested by the composite filling body compaction deformation test. η ct Or the cementitious material dosage in CLSM can be adjusted for secondary control.

[0107] It can be seen that the fluidized filling and disposal method for synergistic loss reduction mining in coal-based solid waste caving areas provided in this embodiment has the following advantages over the existing technology:

[0108] First, this method fills CLSM during the dynamic compaction process of the coal seam mining caving area. It is based on the disposal needs of coal-based solid waste in and around the mine and the dynamic evolution law of the mine caving area. It gives full play to the spatial resource value of the coal mine caving area and the filling properties of coal-based solid waste materials, scientifically arranges the filling space of the caving area, and can achieve a positive balance between the utilization of spatial resources in the caving area and the disposal of solid waste sources.

[0109] Second, this method implements coordinated loss reduction mining of coal-based solid waste caving fluidized filling disposal by forming a pre-mining space coordination - mining and filling process coordination - storage and waste loss reduction coordination system. It can adapt to the green and efficient disposal and loss reduction mining of multi-source coal-based solid waste, and will effectively solve the problem of large-scale ground gangue storage and large underground goafs that aggravate the damage to the ecological environment of the mining area. It has the characteristics of high waste storage efficiency, efficient coordination of waste storage and loss reduction, and significant economic benefits.

[0110] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for fluidized filling and disposal of coal-based solid waste caving areas in a coordinated loss reduction mining process, characterized in that: include: Based on the positive equilibrium relationship between the volume of the filling material and the filling space of the caving area, the volume of the filling material is matched with the filling space of the caving area to screen out the filling space of the caving area that meets the conditions; the filling material is pre-prepared based on the coal-based solid waste to be filled and disposed of in the mine and its surrounding areas; The filling space of the caving area is calculated based on the coal seam production volume, the surface subsidence volume and the unloading expansion volume of the fracture zone and the curved subsidence zone; Based on the screened working surface of the caving area filling space and the position of the arch foot of the semi-arch structure, the filling operation of the caving area filling space is divided into multiple filling windows; According to the sequence of the filling windows, the backward fluidized filling method is used to carry out the filling operation of each filling window in turn until the filling operation corresponding to the last filling window is completed.

2. The method for collaborative loss reduction mining by fluidized filling treatment of coal-based solid waste caving areas according to claim 1 is characterized in that: The method of matching the volume of the filling material with the filling space of the caving area based on the positive equilibrium relationship between the volume of the filling material and the filling space of the caving area includes: According to the positive equilibrium relationship between the volume of the filling material and the filling space of the caving area, the volume of the filling material is matched with the filling space of the caving area; The positive equilibrium relationship is specifically expressed as follows: Where, V c Indicates the filling space of the caving area; V f Indicates the volume of filling material; The calculation formula for the filling space of the caving area is as follows: Where, V 1 represents the coal seam mined volume; V 2 represents the volume of surface subsidence; V 3 represents the unloading expansion volume of the fracture zone and the bending subsidence zone; k It represents the space utilization coefficient of the caving area, which is obtained based on the filling test.

3. The method for collaborative loss reduction mining by fluidized filling treatment of coal-based solid waste caving areas according to claim 1 is characterized in that: Based on the screened working surface of the caving area filling space and the position of the arch foot of the semi-arch structure, the filling operation of the caving area filling space is divided into multiple filling windows, including: Obtaining the positions of the working face and the arch foot of the semi-arch structure in the filling space of the caving area; the semi-arch structure is an arch-shaped stress partition formed by the deflection of the principal stress of the overlying bedrock in the mining area caused by the periodic breaking of the roof during the mining process of the working face; According to the position of the working face of the filling space in the caving area and the arch foot of the semi-arch structure, the mining time of the filling operation of the filling space in the caving area is obtained, and the mining time is divided into multiple filling windows.

4. The method for collaborative loss reduction mining by fluidized filling treatment of coal-based solid waste caving areas according to claim 3 is characterized in that: Before dividing the filling operation of the caving area filling space into a plurality of filling windows based on the working surface of the caving area filling space obtained by screening and the position of the arch foot of the semi-arch structure, the method further includes: A charging port is pre-arranged at the boundary position of the filling space of the caving area corresponding to the arch foot of the semi-arch structure; the charging port includes multiple groups of filling boreholes and filling pipes; the filling boreholes are distributed in the coal pillars along the goaf tunnel and the caving area, and the filling pipes are reserved and arranged in the tail tunnel of the working face.

5. The method for collaborative loss reduction mining by fluidized filling treatment of coal-based solid waste caving areas according to claim 4 is characterized in that: Before dividing the filling operation of the caving area filling space into a plurality of filling windows based on the working surface of the caving area filling space obtained by screening and the position of the arch foot of the semi-arch structure, the method further includes: Arrange the filling system of the caving area, including: Connect the filling station with the filling pipeline, and introduce the filling pipeline into the underground main tunnel and gob-side tunnel in sequence; Connect the filling pipeline introduced into the gob-side tunnel to the filling port through a branch pipe, or after introducing the branch pipe into the tail tunnel of the working face, connect the branch pipe to the reserved filling pipe; Each branch pipe is provided with a material distribution valve and an online detector, and the online detector is used for online monitoring of flow, pressure and viscosity.

6. The method for collaborative loss reduction mining by fluidized filling treatment of coal-based solid waste caving areas according to claim 1 is characterized in that: Before the filling operation of each filling window period is carried out in sequence by adopting the backward fluidized filling method according to the sequence of the filling window periods, the method further includes: Coal-based solid waste is used to pre-prepare filling materials, and the filling materials are controllable low-strength materials; wherein the preparation process of the controllable low-strength materials is as follows: Crushing coal-based solid waste raw materials into graded particles; The graded particles are uniformly mixed with the cementitious material and the water reducing agent according to a preset ratio, and after mixing, mine water is added to prepare a controllable low-strength material; Wherein, the coal-based solid waste raw material is coal gangue or a combination of coal gangue and at least one of fly ash, slag, gasified slag, and desulfurized gypsum; The graded particles are continuously graded particles with a particle size of less than 5 mm, and the mass of particles with a particle size of less than 0.3 mm accounts for at least 15% of the total mass of the continuously graded particles.

7. The method for collaborative loss reduction mining by fluidized filling treatment of coal-based solid waste caving areas according to claim 6 is characterized in that: The coal-based solid waste raw materials include coal gangue, and the mass of the coal gangue accounts for at least 60% of the total mass of the coal-based solid waste raw materials.

8. The method for synergistic loss reduction mining by fluidized filling treatment of coal-based solid waste caving areas according to claim 6, characterized in that: The mass concentration of the controllable low-strength material is 72% to 77%, the slump is ≥220 mm, and the mass ratio of the water reducer to the cementitious material is 0.3% to 0.6%; when the controllable low-strength material is mixed with a low-activity cementitious material, the mass of the cementitious material is the total mass of the cement and the low-activity cementitious material; the low-activity cementitious material is at least one of fly ash, slag powder and furnace slag powder.

9. The method for collaborative loss reduction mining by fluidized filling treatment of coal-based solid waste caving areas according to claim 1 is characterized in that: The method of sequentially performing the filling operation of each filling window period by adopting the backward fluidized filling method until the filling operation corresponding to the last filling window period is completed includes: Based on the calculated filling rate of the caving area and the subsidence of the loss-reduction control layer, the effect of fluidized filling and waste storage and coordinated loss-reduction mining in the caving area is characterized to achieve effect evaluation.

10. The method for collaborative loss reduction mining by fluidized filling treatment of coal-based solid waste caving areas according to claim 9 is characterized in that: Before characterizing the effect of fluidized filling, storage and wastewater synergistic loss reduction mining in the caving area based on the calculated filling rate of the caving area and the subsidence of the loss reduction control layer, the method further includes: Based on the volume of the filling material filled into the caving area and the filling space of the caving area, the filling rate of the caving area is calculated. The specific formula is as follows: Where, η ct is the filling rate of the caving area; V ct is the volume of filling material filled into the caving area; V 1 represents the coal seam mined volume; V 2 represents the volume of surface subsidence; V 3 represents the unloading expansion volume of the fracture zone and the bending subsidence zone; k Indicates the space utilization coefficient of the caving area; The subsidence of the damage reduction control layer before filling, the compaction rate of the composite filling body, the expansion coefficient of the caving rock mass, and the total thickness of the caving zone rock layer are used to calculate the subsidence of the damage reduction control layer. The specific formula is as follows: Where, w j To reduce the subsidence of the control layer; w z It is the subsidence of the loss-control layer before filling; η c is the compaction rate of composite filling; K p is the expansion coefficient of the falling rock mass; ∑ h It is the total thickness of rock strata in the caving zone.

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