Mine filling method based on self-compacting tailings mortar bonded block stones

Abstract

The present application discloses a mine filling method based on self-compacting tailings mortar bonded with rubble, and the method includes: classifying mining wastes generated during the mine exploitation process to obtain tailings and waste rocks at multiple levels; calculating the water-binder ratio based on the target binder and determining the material dosage ratio of the self-compacting tailings mortar; combining the material dosage ratio and using the target binder and the treated tailings and waste rocks to prepare the self-compacting tailings mortar; conducting multi-level quality evaluation on the tailings mortar to screen out qualified batches of tailings mortar; determining the layer thickness of the mine goaf filling plan based on the filling performance of the qualified batches of tailings mortar; using the treated waste rocks to conduct rubble filling on the goaf and using the qualified batches of tailings mortar to pour the areas filled with rubble to complete the mine filling. Through the solution of the present application, the mine can achieve zero solid waste and at the same time reduce the filling cost.

Description

Technical Field

[0001] The present application relates to the field of mine filling, and particularly to a mine filling method based on self-compacting tailings mortar-cemented crushed stones. Background Art

[0002] Mine filling has become a crucial technology in modern mining industry. Its main purpose is to backfill waste or other materials into the mined-out area to support the ground surface, prevent ground subsidence, improve the recovery rate of mineral resources, and reduce environmental pollution. With the continuous increase of the mining depth of mineral resources and the increasingly strict environmental protection requirements, efficient, safe and environmentally friendly filling methods become particularly important. Mine filling can not only improve the safety of mines, but also realize the resource utilization of waste, reduce the land occupation of surface storage, and reduce environmental risks. At present, the commonly used mine filling methods mainly include hydraulic filling, paste filling and dry filling, etc. Hydraulic filling is to mix tailings with water to form a slurry and transport it to the mined-out area; paste filling is to mix tailings with a gelling material to make a high-concentration paste for filling; dry filling usually directly backfills waste rocks or other solid materials. The working principles of these methods are basically to send the filling materials into the mined-out area through pipeline transportation or mechanical transportation to form a support body. However, there are some problems in these existing technologies, such as insufficient strength of the filling body, low filling efficiency, easy segregation phenomenon, high filling cost, etc. These problems seriously restrict the further development and application of mine filling technology.

[0003] To solve the above problems, the industry has proposed a variety of improvement methods. For example, optimizing the filling material ratio to improve the strength of the filling body; adopting a new type of conveying equipment to improve the filling efficiency; developing special additives to reduce the segregation phenomenon; researching new gelling materials to reduce the cost, etc. However, while solving some problems, these methods often bring new challenges. For example, increasing the strength of the filling body may increase the cost or reduce the fluidity; improving the filling efficiency may exacerbate the segregation phenomenon; using special additives may introduce new environmental risks.

[0004] Therefore, there is an urgent need for a technical solution that can enable mines to achieve zero solid waste while reducing the filling cost. Summary of the Invention

[0005] To solve the deficiencies of the prior art, the embodiments of the present application provide a mine filling method based on self-compacting tailings mortar-cemented crushed stones. The present application solves the technical problems such as large environmental pollution and high filling cost in the prior art.

[0006] The embodiment of the present application provides a mine filling method based on self-compacting tailings mortar bonded with rubble, including: classifying mining wastes generated during the mine exploitation process to obtain tailings and waste rocks at multiple levels; calculating the water-binder ratio based on the target binder and determining the material dosage ratio of the self-compacting tailings mortar; preparing the self-compacting tailings mortar by combining the material dosage ratio and using the target binder and the treated tailings and waste rocks; conducting multi-level quality evaluation on the tailings mortar to screen out qualified batches of tailings mortar; determining the layered thickness of the mine goaf filling plan based on the filling performance of the qualified batches of tailings mortar; filling the goaf with the treated waste rocks in the form of rubble and pouring the areas filled with rubble with the qualified batches of tailings mortar to complete the mine filling.

[0007] In a possible implementation manner, classifying the mining wastes generated during the mine exploitation process to obtain tailings and waste rocks at multiple levels includes: dehydrating the tailings slurry of the mining wastes by using a filter press; performing tailings classification by using a hydrocyclone or a vibrating screen to divide the dehydrated tailings into fine tailings and coarse tailings; dividing the waste rocks of the mining wastes into small-sized waste rocks, medium-sized waste rocks, and large-sized waste rocks according to the particle size.

[0008] In a possible implementation manner, calculating the water-binder ratio based on the target binder and determining the material dosage ratio of the self-compacting tailings mortar includes: using portland cement as the target binder and determining the water-binder ratio by using the cement strength; determining the dosage of the fine tailings according to the binder dosage and the water-binder ratio; where it includes: F 1 = 0.45×(1000 - B - Bα)×(1 - 0.1ln(1 + S 1 )), where F 1 represents the dosage of the fine tailings, B represents the binder dosage, α represents the water-binder ratio, and S 1 represents the fineness modulus of the fine tailings; determining the dosage of the coarse tailings according to the binder dosage and the water-binder ratio; where it includes: where F 2 represents the dosage of the coarse tailings, D represents the maximum particle size of the coarse tailings, and the unit is mm; determining the dosage of the small-sized waste rocks according to the binder dosage and the water-binder ratio; where it includes: where S represents the dosage of the small-sized waste rocks and A represents the water absorption rate of the small-sized waste rocks.

[0009] In a possible implementation manner, determining the water-binder ratio by using the cement strength includes: where α represents the water-binder ratio, f c represents the cement strength in MPa, J represents the first coefficient with a value of 93, and K represents the second coefficient with a value of 1.5.

[0010] In one possible implementation, self-compacting tailings mortar is prepared by combining the dosage ratio of materials and using the target cementitious material, treated tailings, and waste rock, including: stirring the cementitious material containing fly ash and / or slag powder admixture, determined amounts of fine tailings and coarse tailings in a dry mixer for 2 - 3 minutes; adding water and polycarboxylate water reducer and stirring for 3 - 4 minutes; adding determined amounts of small-sized waste rock and water and stirring for 2 - 3 minutes; adding a viscosity modifier and stirring for 1 - 2 minutes until the slurry is uniform to obtain self-compacting tailings mortar.

[0011] In one possible implementation, multi-level quality evaluation is performed on the tailings mortar to screen out qualified batches of tailings mortar, including: performing a slump flow test on the self-compacting tailings mortar to mark the tailings mortar with a final spread diameter ≥ 650 mm and no obvious segregation phenomenon as first-class tailings mortar; performing a V-funnel test on the first-class tailings mortar to mark the tailings mortar with an outflow time of 8 - 12 seconds as second-class tailings mortar; performing a U-box test on the second-class tailings mortar to mark the tailings mortar with a height difference between both sides ≤ 30 mm as third-class tailings mortar; marking the production batch of the screened third-class tailings mortar as a qualified batch.

[0012] In one possible implementation, the layer thickness of the mined-out area filling plan is determined based on the filling performance of the qualified batch of tailings mortar, including: testing and obtaining the filling performance characteristics of the qualified batch of tailings mortar; determining the filling thickness, number of layers, and filling sequence of each layer according to the filling performance characteristics; including:

[0013] Where, T represents the filling thickness of each layer, C represents the fluidity index of the tailings mortar, H represents the strength development coefficient, L represents the setting time coefficient, N represents the number of layers, z max represents the maximum height of the mined-out area, i represents the number of layers, F(i) represents the filling sequence, ρ(x i , y i , z i ) represents the filling density function, v(x i , y i , z i ) represents the filling stress field vector function, μ represents the density threshold, sgn() represents the sign function. When F(i) ≤ 0, it is marked as a first-class target layer area, and only block stone filling is performed on the current layer. When F(i) > 0, it is marked as a second-class target layer area, and tailings mortar pouring is performed after block stone filling on the current layer.

[0014] In one possible implementation, waste rock after treatment is used to fill the mined - out area with block stones, and qualified batch tailing mortar is used to pour the area filled with block stones to complete mine filling, including: using waste rock to fill the first - type target layer area with block stones; when using tailing mortar to pour the second - type target layer area, controlling the pumping flow rate and pouring speed based on the geometric characteristics of the layer area.

[0015] In one possible implementation, after completing mine filling, it further includes: conducting periodic on - site inspections on the mined - out area during the filling process to determine that the density and mechanical properties of the current filling layer area reach the target thresholds.

[0016] In the mine filling method based on self - compacting tailing mortar - bonded block stones provided above, in the embodiments of the present application, by combining self - compacting tailing mortar with block stone filling, efficient utilization of mine solid waste and significant reduction of filling costs are achieved. Further, in some embodiments, by classifying and using waste rocks of different particle sizes, the filling cost and the surface stacking pressure are greatly reduced. Further, in some embodiments, by adopting the method of combining layered filling with self - compacting slurry, the filling efficiency and quality are improved. Further, in some embodiments, by establishing a complete quality control system, it can ensure that the performance of the filling body meets the engineering requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a schematic flow chart of a mine filling method based on self - compacting tailing mortar - bonded block stones provided by the embodiments of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] Now, various exemplary embodiments of the present application will be described in detail with reference to the drawings. It should be noted that: unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and values set forth in these embodiments do not limit the scope of the present application.

[0020] Those skilled in the art can understand that terms such as "first" and "second" in the embodiments of the present application are only used to distinguish different steps, devices or modules, etc., and neither represent any specific technical meaning nor indicate an inevitable logical order between them. It should also be understood that in the embodiments of the present application, "a plurality of" may refer to two or more, and "at least one" may refer to one, two or more. It should also be understood that for any component, data or structure mentioned in the embodiments of the present application, without clear limitation or contrary indication in the context, it can generally be understood as one or more. In addition, the term "and / or" in the present application is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present application generally represents an "or" relationship between the associated objects before and after. It should also be understood that the present application emphasizes the differences between the various embodiments, and their similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail one by one.

[0021] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The following description of at least one exemplary embodiment is actually merely illustrative and in no way limits the present application and its application or use. Technologies, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods and devices should be regarded as part of the specification. It should be noted that: similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0022] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0023] Figure 1Schematic flow chart of a mine filling method based on self-compacting tailings mortar-cemented rubble provided by an embodiment of the present application. It should be understood that a large amount of tailings and waste rocks are generated during the mine exploitation process, and there are problems such as high cost and low resource utilization rate in traditional filling methods. The technical solution of the present application aims to develop a new mine filling method, which realizes the goals of "zero solid waste" and cost reduction by improving the tailings cementitious material and combining rubble filling. That is, based on the technology of mass concrete, the tailings are improved into self-compacting slurry, and waste rocks with different particle sizes are used as aggregates and filling materials. By optimizing the ratio and process, a filling system with high fluidity, self-compactability and good mechanical properties is realized.

[0024] As Figure 1 shown, in step S101, the mining wastes generated during the mine exploitation process are classified to obtain tailings and waste rocks of multiple levels. Among them, a filter press is used to dehydrate the tailings slurry of the mining wastes; a hydrocyclone or a vibrating screen is used for tailings classification to divide the dehydrated tailings into fine tailings and coarse tailings; the waste rocks of the mining wastes are divided into small-sized waste rocks, medium-sized waste rocks and large-sized waste rocks according to the particle size.

[0025] Specifically, first, raw material preparation is carried out. For tailings treatment, tailings dehydration is carried out, and a filter press is used to dehydrate the tailings slurry to a moisture content of about 15%. Tailings classification is carried out, and a hydrocyclone or a vibrating screen is used for tailings classification to divide the tailings into fine tailings (<0.074 mm) and coarse tailings (0.074 - 2 mm). The calculation formula for the proportion of fine tailings is: P1 = M1 / (M1 + M2) × 100% where, P1 is the proportion of fine tailings, M1 is the mass of fine tailings, and M2 is the mass of coarse tailings.

[0026] For waste rock treatment, waste rock classification is carried out, and the waste rocks mined underground can be divided into three categories according to the particle size:

[0027] Small-sized waste rocks (2 - 20 mm): used as coarse aggregates for self-compacting tailings concrete;

[0028] Medium-sized waste rocks (20 - 300 mm): directly used for preliminary filling of the goaf;

[0029] Large-sized waste rocks (>300 mm): need to be crushed before use.

[0030] Then, waste rock cleaning can be carried out. A high-pressure water gun is used to clean the surface of the waste rocks to remove dust and impurities, or it can be directly used without cleaning.

[0031] At step S102, calculate the water-cement ratio based on the target cementitious material and determine the material dosage ratio of the self-compacting tailings mortar. Specifically, include using portland cement as the target cementitious material and determining the water-cement ratio using the cement strength. In one embodiment, ordinary portland cement (P.O 42.5) can be selected as the main cementitious material. Then, design the mix ratio of the self-compacting tailings mortar, and the mix ratio design can follow the following principles: ensure high fluidity and self-compactability, ensure that the filling body has sufficient strength, maximize the utilization of tailings and waste rocks, and control costs. Among them, determining the water-cement ratio using the cement strength includes: Where α represents the water-cement ratio, f c represents the cement strength in MPa, J represents the first coefficient with a value of 93, and K represents the second coefficient with a value of 1.5. Cement with a strength of 0.45 - 0.50 can be selected to ensure fluidity and strength. The dosage of the cementitious material B = 150 - 200 kg / m 3 . It should be noted that this is a simplified model, and adjustments may be required according to specific situations in actual applications. For different types of cement or when adding mineral admixtures, the values of J and K may need to be adjusted. Other factors, such as workability and durability requirements, also need to be considered during actual mixing. Trial mixing and experimental verification can be carried out before actual application. This method provides a way to quickly estimate the water-cement ratio and is suitable for preliminary design or rapid evaluation. For more precise mix ratio design, more factors and experimental data need to be combined.

[0032] Determine the fine tailings dosage according to the cementitious material dosage and the water-cement ratio; it includes: F 1 = 0.45×(1000 - B - Bα)×(1 - 0.1ln(1 + S 1 )), where F 1 represents the fine tailings dosage, B represents the cementitious material dosage, α represents the water-cement ratio, and S 1 represents the fineness modulus of the fine tailings;

[0033] Determine the coarse tailings dosage according to the cementitious material dosage and the water-cement ratio; it includes where F 2 represents the coarse tailings dosage, and D represents the maximum particle size of the coarse tailings in mm;

[0034] Determine the dosage of small-sized waste rocks according to the cementitious material dosage and the water-cement ratio; it includes: where S represents the dosage of small-sized waste rocks, and A represents the water absorption rate of the small-sized waste rocks.

[0035] In addition, the dosage of admixtures can be configured as follows: high-range water reducer: 1.0 - 1.5%×B, viscosity modifier: 0.05 - 0.1%×B.

[0036] At step S103, self-compacting tailings mortar is prepared by combining the material dosage ratio and using the target cementitious material, treated tailings and waste rock.

[0037] In one embodiment, a cementitious material containing fly ash and / or slag powder admixture and determined amounts of fine tailings and coarse tailings are stirred in a dry mixer for 2 - 3 minutes; adding fly ash and slag powder as admixtures can improve the fluidity and late strength of the slurry. Water and polycarboxylate water reducer are added and stirred for 3 - 4 minutes; determined amounts of small-sized waste rock and water are added and stirred for 2 - 3 minutes; a viscosity modifier is added and stirred for 1 - 2 minutes until the slurry is uniform to obtain self-compacting tailings mortar.

[0038] Specifically, high-precision metering equipment can be used to accurately weigh each component material according to the ratio. Premixing of dry materials: The cementitious material (cement, fly ash, slag powder), fine tailings and coarse tailings are stirred in a dry mixer for 2 - 3 minutes. Wet mixing: 80% of the water and polycarboxylate water reducer are added and stirred for 3 - 4 minutes. Secondary feeding: Small-sized waste rock and the remaining water are added and stirring continues for 2 - 3 minutes. Final mixing: A viscosity modifier is added and finally stirred for 1 - 2 minutes until the slurry is uniform.

[0039] At step S104, multi-level quality evaluation is carried out on the tailings mortar to screen out qualified batches of tailings mortar.

[0040] In one implementation scenario, a slump flow meter is used to test the fluidity of the slurry. The slump flow test is carried out on the self-compacting tailings mortar, and the tailings mortar with a final spread diameter ≥ 650 mm and no obvious segregation phenomenon is marked as first-class tailings mortar.

[0041] The V-funnel test is carried out on the first-class tailings mortar to test the viscosity and passing ability of the slurry, and the tailings mortar with an outflow time of 8 - 12 seconds is marked as second-class tailings mortar.

[0042] The U-box test is carried out on the second-class tailings mortar to evaluate the self-compacting property and segregation resistance of the slurry, and the tailings mortar with a height difference ≤ 30 mm on both sides is marked as third-class tailings mortar.

[0043] The production batches of the third-class tailings mortar screened out are marked as qualified batches.

[0044] At step S105, the layer thickness of the goaf filling plan is determined based on the filling performance of the qualified batch of tailings mortar. Specifically, it includes: testing and obtaining the filling performance characteristics of the qualified batch of tailings mortar; determining the filling thickness, number of layers and filling sequence of each layer according to the filling performance characteristics.

[0045] Furthermore, it includes:

[0046]

[0047] Among them, T represents the filling thickness of each layer, C represents the fluidity index of the tailings mortar, H represents the strength development coefficient, L represents the setting time coefficient, N represents the number of layers, z max represents the maximum height of the goaf, i represents the number of layers, F(i) represents the filling sequence, ρ(x i ,y i ,z i ) represents the filling density function, v(x i ,y i ,z i ) represents the filling stress field vector function, μ represents the density threshold, sgn() represents the sign function. When F(i) ≤ 0, it is marked as a first-class target layer area, and only block stone filling is carried out for the current layer. When F(i) > 0, it is marked as a second-class target layer area, and tailings mortar pouring is carried out after block stone filling of the current layer.

[0048] This method can not only effectively utilize tailings resources, but also improve the filling effect and ensure the long-term stability of the goaf. Next, the specific implementation process of this method will be elaborated in detail, including filling performance testing, calculation of layered thickness, and determination of filling sequence, etc.

[0049] First of all, conducting the filling performance test of the tailings mortar is the basis for determining the layered filling scheme. Three main methods, namely fluidity test, compressive strength test, and setting time test, can be used to evaluate the filling performance of the tailings mortar. Taking a copper mine as an example, a KZJ-5000 type automatic constant stress pressure testing machine is used for the compressive strength test, and the compressive strength of the tailings mortar at 28 days of age is measured to be 3.2 MPa. The fluidity test uses an NLD-3 type mortar fluidity tester, and the spread of the tailings mortar is measured to be 220 mm. The setting time test uses a VST-2000 type setting time tester, with the initial setting time being 4 hours and the final setting time being 8 hours.

[0050] Based on these test results, the fluidity index C, strength development coefficient H, and setting time coefficient L of the tailings mortar can be determined. Here, a mathematical model is introduced to calculate these parameters: Among them, F 28 is the compressive strength at 28 days, F 0 is the reference strength (usually taken as 1 MPa), D is the measured spread, D 0 is the reference spread (usually taken as 200 mm), t f is the final setting time, t i is the initial setting time.

[0051] For the strength development coefficient H, the following calculation formula is proposed in the embodiment of the present application: Among them, F 7 is the compressive strength at 7 days, ρ is the density of the tailings mortar, ρ0 is the density of water.

[0052] The calculation formula for the setting time coefficient L is as follows: where t 0 is the reference time (usually taken as 1 hour), T is the ambient temperature, and T 0 is the reference temperature (usually taken as 20 °C).

[0053] Substitute the above parameters into the stratified thickness calculation formula: T = V / 2S·(1 + C^2)·√(1 + H^2)·e^(-L / π). In one embodiment, the goaf volume V is 10000 m 3 , the bottom area S is 500 m 2 . Substituting the calculated values of C = 1.2, H = 0.8, and L = 2.5, the filling thickness T of each layer is approximately 2.1 m. Next, the number of layers N needs to be determined. Let the maximum height z_max of the goaf be 30 m, then: N = z_max / T ≈ 14.3. After rounding, the number of layers is 15. After determining the stratified thickness and number, the filling sequence needs to be formulated. Here, a filling sequence judgment function is introduced: where ρ(x_i, y_i, z_i) represents the filling density function, v(x_i, y_i, z_i) represents the filling stress field vector function, and μ represents the density threshold. To describe these functions more accurately, the following specific expressions are disclosed in this application:

[0054] ρ(x_i, y_i, z_i) = ρ_0*(1 + α*z_i / z_max)*(1 + β*(x_i^2 + y_i^2) / (x_max^2 + y_max^2));

[0055] v(x_i, y_i, z_i) = [v_x*(1 - x_i / x_max), v_y*(1 - y_i / y_max), v_z*(z_i / z_max)];

[0056] where ρ_0 is the initial density, α and β are adjustment coefficients, x_max, y_max, and z_max are the maximum dimensions of the goaf in three directions respectively, and v_x, v_y, and v_z are the reference components of the stress field in three directions.

[0057] In practical applications, numerical methods can be used to solve these complex functions. Taking the finite difference method as an example, the goaf can be divided into grids, and then the values of density and stress field are calculated at each grid point. Assuming the grid spacing is 0.5 m, in a 30 m × 20 m × 15 m goaf, the values of 60 × 40 × 30 = 72000 grid points need to be calculated.

[0058] To improve the computational efficiency, parallel computing techniques can be used. For example, by using NVIDIA Tesla V100 GPU accelerators in conjunction with the CUDA parallel computing framework, the computing time can be reduced from several hours on a traditional CPU to just a few minutes. In actual engineering, the embodiments of this application use the self-developed Mine Filling Simulator software package to perform these complex numerical calculations.

[0059] After the calculation is completed, the F(i) value of each layer is obtained. When F(i) ≤ 0, this layer is marked as a first-class target layer area and filled with block stones; when F(i) > 0, this layer is marked as a second-class target layer area, first filled with block stones, and then tailings mortar is poured.

[0060] Through this layer-by-layer filling method based on the filling performance of tailings mortar, the filling process can be controlled more precisely, improving the filling quality. In the actual application of a certain copper mine, after adopting this method, the overall strength of the filling body has increased by 15%, and the settlement of the goaf has decreased by 30%, significantly improving the safety and production efficiency of the mine.

[0061] In summary, determining the layer thickness of the goaf filling plan for a mine based on the filling performance of qualified batches of tailings mortar is a scientific and efficient filling method. By precisely controlling the filling thickness and sequence of each layer, the tailings resources can be utilized to the maximum extent while ensuring the long-term stability of the goaf. This method not only benefits the safe production of the mine but also promotes the sustainable development of the mining industry.

[0062] It should be noted that in actual applications, more accurate parameters and functions can be obtained based on on-site measurements and geological surveys.

[0063] At step S106, the goaf is filled with block stones using the processed waste rock, and the area filled with block stones is poured with qualified batches of tailings mortar to complete the mine filling. This includes: filling the first-class target layer area with block stones using waste rock; when pouring the second-class target layer area with tailings mortar, controlling the pumping flow rate and pouring speed based on the geometric characteristics of the layer area.

[0064] Specifically, in the block stone filling, 300-mm block stones are transported to the goaf. A remotely controlled scraper is used to directly dump the waste rock, allowing it to freely fall to form a block stone rubble body.

[0065] In the self-compacting tailings mortar pouring, a high-pressure delivery pump is used to transport the self-compacting tailings mortar to the filling area. A telescopic pouring pipe is used to pour evenly from bottom to top and from far to near. Pouring speed control: v = Q / (L × H × W), where v is the pouring speed (m / h), Q is the pumping flow rate (m 3 / h), where L is the length of the filling area (m), H is the height of the layer (m), and W is the width of the filling area (m). Control the pouring speed v = 0.3 - 0.5 m / h to ensure that the slurry fully penetrates and wraps the riprap. During the actual filling process, the following points need to be noted:

[0066] Ratio control of the tailings mortar. The ratio of tailings, cement, and water directly affects the filling performance. A ratio of 70% tailings, 8% cement, and 22% water can be adopted. Use a PLG2000 type continuous double-horizontal shaft mixer for mixing to ensure uniform mixing.

[0067] Design of the filling pipeline. Considering the abrasiveness of the tailings mortar, steel pipes lined with high molecular polyethylene can be selected, and the pipe diameter is usually 150 mm. At the pipe bends, use elbows with a large radius of curvature (R / D ≥ 5) to reduce wear and resistance loss.

[0068] Monitoring during the filling process. Use an MFMS - 2000 type filling monitoring system to monitor the filling pressure, flow rate, and slurry concentration in real time. When the filling pressure exceeds 4 MPa or the flow rate is lower than 50 m 3 / h, the system will automatically alarm and stop filling.

[0069] Curing measures. After filling is completed, curing for at least 7 days is required. During the curing period, keep the ambient temperature at 15 - 25 °C and the relative humidity not less than 90%. An automatic spray system can be used to maintain the appropriate humidity.

[0070] Quality inspection. Use a ZBL - U5 non - metallic ultrasonic detector to conduct non - destructive testing on the filling body to evaluate the filling quality. The spacing between detection points is not greater than 5 m, and at least one detection point is set every 100 m 2 at least.

[0071] In addition, after the mine filling is completed, it also includes: conducting periodic on - site inspections on the mined - out area of the mine during the filling process to determine that the density and mechanical properties of the current filling layer area reach the target threshold.

[0072] Specifically, the cycle can be set as follows: Initial stage (0 - 24 hours): 0 hours (immediately after filling), 2 hours later, 4 hours later, 8 hours later, 12 hours later, 24 hours later. Early stage (1 - 7 days): The 2nd day, the 3rd day, the 5th day, the 7th day. Middle stage (1 - 4 weeks): The 10th day, the 14th day, the 21st day, the 28th day. Late stage (1 - 3 months): Inspect once every 7 days. Stable stage (after 3 months): Inspect once every 21 days.

[0073] The on - site inspection can include but is not limited to, slurry fluidity: Conduct a slump flow test for each batch to ensure ≥650 mm. Filling density: Use an acoustic detector to test the filling density of the filling body, requiring ≥95%.

[0074] For the mechanical property test, the compressive strength: Specimens are made and subjected to compressive strength test after standard curing for 7 days and 28 days. Requirements: The strength at 7 days ≥ 3 MPa, and the strength at 28 days ≥ 5 MPa. The elastic modulus is measured using a non-destructive dynamic elastic modulus tester for the 28-day filling body. The elastic modulus calculation formula: E = ρ×(2L×f) 2 / g, where E is the dynamic elastic modulus (MPa), ρ is the density (kg / m 3 ), L is the specimen length (m), f is the fundamental frequency (Hz), and g is the acceleration due to gravity (m / s 2 ). Requirements: The elastic modulus at 28 days ≥ 5 GPa.

[0075] A dust online monitoring system can also be installed in the filling operation area to monitor the dust concentration in real time. Dust concentration control standard: ≤ 4 mg / m 3 . A multi-parameter gas detector is installed to monitor the concentrations of harmful gases such as CO and H2S. Control standards: CO ≤ 30 ppm, H2S ≤ 10 ppm. Multiple-point displacement gauges and stress gauges are arranged around the filling area to monitor the surrounding rock deformation and stress state in real time. Displacement warning value: 20 mm, stress warning value: 80% of the virgin rock stress.

[0076] In summary, this application has developed a new self-compacting tailings mortar formula, achieving the efficient utilization of tailings and excellent performance of the filling body. The waste rocks with different particle sizes are classified and utilized, significantly reducing the filling cost and the surface stacking pressure. By using the method of combined layered filling and self-compacting slurry, the filling efficiency and quality are improved. A complete quality control system is established to ensure that the performance of the filling body meets the engineering requirements.

[0077] In practical applications, compared with the traditional cement mortar filling method, the filling cost is reduced by 30 - 40%. The tailings utilization rate is increased to over 95%, and the waste rock utilization rate reaches 100%. The 28-day compressive strength of the filling body ≥ 5 MPa, meeting the requirements of mining engineering. The "zero solid waste" discharge of the mine is realized, meeting the requirements of green mine construction.

[0078] All in all, the technical solution of this application innovatively combines self-compacting tailings mortar with block stone filling, achieving the efficient utilization of mine solid waste and a significant reduction in filling cost. This method not only improves the filling quality but also provides a new technical approach for green mine construction, contributing to the sustainable development of the mine.

[0079] As can be seen from the description of the above embodiments, those skilled in the art can clearly understand that all or part of the steps in the above-described embodiment methods can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network communication device such as a media gateway, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the present application.

[0080] It should be noted that the various embodiments in this specification are described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple. For the relevant parts, reference can be made to the description in the method part.

[0081] It should also be noted that in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0082] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A mine filling method based on self-compacting tailings mortar cemented rock, characterized in that: include: Classify and process the mining waste generated during mining to obtain multiple levels of tailings and waste rock; The water-binder ratio is calculated based on the target cementitious material, and the material dosage ratio of the self-compacting tailings mortar is determined; wherein, it includes: taking silicate cement as the target cementitious material, and determining the water-binder ratio by using cement strength; determining the amount of fine tailings according to the amount of cementitious material and the water-binder ratio; wherein, it includes: F1=0.45×(1000-B-Bα)×(1-0.1ln(1+S1)), wherein, F1 represents the amount of fine tailings, B represents the amount of cementitious material, α represents the water-binder ratio, and S1 represents the fineness modulus of fine tailings; determining the amount of coarse tailings according to the amount of cementitious material and the water-binder ratio; wherein, it includes: Among them, F2 represents the amount of coarse tailings, D represents the maximum particle size of coarse tailings, the unit is mm; the amount of small-size waste rock is determined according to the amount of cementitious material and the water-binder ratio; including: Among them, S represents the amount of small-size waste rock, and A represents the water absorption rate of small-size waste rock; Combining the material dosage ratio and using the target cementitious material and the treated tailings and waste rock to prepare a self-compacting tailings mortar; Carry out multi-level quality assessment on tailings slurry to screen out qualified batches of tailings slurry; Determine the layer thickness of the mine goaf filling plan based on the filling performance of the qualified batch of tailings mortar; including: test to obtain the filling performance characteristics of the qualified batch of tailings mortar; determine the filling thickness of each layer and the number of layers according to the filling performance characteristics; including: Among them, V represents the volume of the goaf, S represents the bottom area of ​​the goaf, T represents the filling thickness of each layer, C represents the fluidity index of tailings mortar, H represents the strength development coefficient, L represents the setting time coefficient, N represents the number of layers, and z max Indicates the maximum height of the goaf; The processed waste rock is used to fill the mined-out area with blocks, and the qualified batch of tailings mortar is used to pour the block filling area to complete the mine filling.

2. The mine filling method according to claim 1, characterized in that: in, The mining waste generated during mining is classified and processed to obtain multiple levels of tailings and waste rock, including: Use filter press to dewater the tailings slurry of mining waste; Use a cyclone or vibrating screen to classify tailings to separate the dewatered tailings into fine tailings and coarse tailings; The waste rock of mining waste is divided into small-size waste rock, medium-size waste rock and large-size waste rock according to its particle size.

3. The mine filling method according to claim 2, characterized in that: in, Use cement strength to determine the water-cement ratio, including: Among them, α represents the water-binder ratio, f c It represents cement strength in MPa, J represents the first coefficient, which is 93, and K represents the second coefficient, which is 1.

5.

4. The mine filling method according to claim 2, characterized in that: in, Combining the material dosage ratio and using the target cementitious material and the treated tailings and waste rock to prepare the self-compacting tailings mortar, including: Mixing the cementitious material including fly ash and / or slag powder admixture and a determined amount of fine tailings and coarse tailings in a dry mixer for 2-3 minutes; Add water and polycarboxylate water reducer and stir for 3-4 minutes; Add a determined amount of small-size waste rock and water and stir for 2-3 minutes; Add viscosity modifier and stir for 1-2 minutes until the slurry is uniform to obtain self-compacting tailings mortar.

5. The mine filling method according to claim 1, characterized in that: in, The tailings slurry is subjected to multi-level quality assessment to screen out qualified batches of tailings slurry, including: The self-compacting tailings mortar is tested for slump expansion, and the tailings mortar with a final expansion diameter ≥ 650mm and no obvious segregation phenomenon is marked as the first-class tailings mortar; A V-funnel test is conducted on the first-level tailings slurry to mark the tailings slurry with a flow time of 8-12 seconds as the second-level tailings slurry; A U-box test is conducted on the second-level tailings mortar to mark the tailings mortar with a height difference of ≤30mm on both sides as the third-level tailings mortar; The production batches of the screened-out third-level tailings mortar are marked as qualified batches.

6. The mine filling method according to claim 1, characterized in that: in, Use the processed waste rock to fill the mined-out area with blocks, and use qualified batches of tailings mortar to pour the block filling area to complete the mine filling, including: Use waste rock to carry out block filling in the target layer area of ​​type I; When tailings mortar is used to pour the second type of target layer, the pumping flow rate and pouring speed are controlled based on the layer's geometric characteristics.

7. The mine filling method according to claim 1, characterized in that: in, After the mine is filled, it also includes: Periodic on-site inspections are carried out on the goaf of the mine during the filling process to determine whether the density and mechanical properties of the current filling layer area have reached the target threshold.

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