Layered composite filling method for large-aperture blast holes in strip mine

Abstract

The invention provides a layered composite filling method for open-pit mine large-aperture blast holes, and belongs to the field of open-pit mine blasting. Through the layered design of a bottom isolating and stabilizing layer, an anti-punching main layer, a dust falling and dust inhibiting layer, a damping buffer layer and a top sealing cover layer, a modified polyurethane foaming material and an intelligent monitoring technology are combined; the packing layer has the comprehensive functions of isolating punched holes, suppressing dust, damping and preventing dust diffusion. According to the method, while it is ensured that functions are improved, rock powder, gravel and cheap industrial and agricultural by-products which are easy to obtain in a mine site are utilized to the maximum extent, and economic feasibility is ensured.

Description

Technical Field

[0001] The present application relates to the technical field of open-pit mine blasting, and in particular to a layered composite filling method for large-diameter blastholes in open-pit mines. Background Art

[0002] In open-pit mine blasting, the quality of blasthole filling has a direct relationship with the utilization rate of blasting energy, control of ore rock block size, generation of flying rocks and dust, and vibration. Traditional filling often uses rock powder, crushed stone or sandy materials, which are difficult to simultaneously meet the multiple requirements of density, dust suppression, shock absorption and punching control in large-diameter blastholes. When the aperture is large, simple filling is prone to problems such as hole punching, increased flying rocks and unsatisfactory block size. Specifically: 1. Insufficient filling materials: It is difficult to fully compact the hole with pure crushed stone or fine materials, resulting in rapid pressure relief, dust diffusion and enhanced vibration at the moment of blasting; the use of high-performance filling materials (such as static crushing agents) can improve the sealing effect, but the cost is high and the construction is complicated, which limits large-scale application. 2. The problem of single function: Traditional filling methods mostly focus only on hole sealing, lack of comprehensive optimization design of anti-punching, dust reduction and shock absorption functions, and the filling layer is difficult to meet the diverse needs of dynamic blasting environments. 3. Lack of intelligent monitoring: The density, expansion rate and curing effect of the filling layer cannot be monitored in real time during the construction process, resulting in unstable construction quality.

[0003] In view of this, it is necessary to design an improved layered composite filling method for large-diameter blastholes in open-pit mines to solve the above problems. Summary of the invention

[0004] In view of the technical problems existing in the background technology, the present application provides a layered composite filling method for large-diameter blastholes in open-pit mines. By combining modified polyurethane (PU) foam materials, multifunctional layered design and intelligent monitoring technology, the comprehensive improvement of hole sealing performance, environmental protection effect and blasting safety is achieved.

[0005] The present application provides a layered composite filling method for large-diameter blastholes in an open-pit mine, comprising the following steps:

[0006] S1. Fill rock powder above the explosive layer to form a bottom isolation and stabilization layer;

[0007] S2. Fill large-size gravel above the bottom isolation stabilization layer and inject modified polyurethane foam material to fill the gap to form an anti-punching main layer;

[0008] S3. Fill a mixture of clay powder and medium-sized gravel above the anti-punching main layer to form a dust reduction and dust suppression layer;

[0009] S4. Fill the top with rock powder and spray water to make the surface slightly crusted to form a top capping layer.

[0010] As a further improvement of the present application, in step S1, the thickness of the bottom isolation and stabilization layer is 1.5 to 2 m.

[0011] As a further improvement of the present application, in step S2, the thickness of the anti-punching main layer is 1.5 to 2 m; and / or the particle size of the large-particle crushed stone is 30 to 50 mm; and / or the volume ratio of the large-particle crushed stone to the modified polyurethane foam material is (80 to 90): (10 to 20).

[0012] Furthermore, the modified polyurethane foam material is a single-component polyurethane foam material containing 1 to 3% of silicon dioxide nanoparticles.

[0013] As a further improvement of the present application, in step S3, the thickness of the dust reduction and dust suppression layer is 1 to 1.5 m; and / or the volume ratio of the clay powder to the medium-sized gravel is (5 to 15): (85 to 95).

[0014] Furthermore, the clay powder is at least one of bentonite and common clay; and / or the particle size of the medium-sized gravel is 5 to 20 mm.

[0015] As a further improvement of the present application, in step S4, the thickness of the top cover layer is 0.5 to 1 m.

[0016] As a further improvement of the present application, a mixture of natural fiber and lightweight aggregate is filled between the dust reduction and dust suppression layer and the top covering layer to form a shock absorbing and buffering layer.

[0017] Furthermore, the thickness of the shock-absorbing buffer layer is 1 to 1.5 m; and / or the volume ratio of the natural fiber to the lightweight aggregate is (5 to 10): (90 to 95); and / or the natural fiber is at least one of coconut shell fiber and straw fiber.

[0018] As a further improvement of the present application, it also includes arranging pressure sensors, ultrasonic reflection monitoring devices, thermal imaging equipment and mechanical strength testing equipment in the anti-punching main layer, and arranging dust detectors and vibration sensors at the hole opening and surrounding areas.

[0019] The beneficial effects of this application are:

[0020] The present application provides a layered composite filling method for large-diameter blastholes in open-pit mines, which is suitable for the filling process of large-diameter (>165mm) blastholes. Through multifunctional layered design, modified polyurethane foam materials and intelligent monitoring technology, the filling layer has the comprehensive functions of isolating punching, dust suppression, shock absorption and preventing dust diffusion. This method ensures the realization of functional improvement while making the best use of rock powder, gravel and cheap industrial and agricultural by-products that are easily available on the mine site to ensure economic feasibility.

[0021] (1) Significantly reduce hole punching and flying stones

[0022] The modified PU foam material in the anti-punching main layer combined with the large-size crushed stone skeleton significantly improves the density and compression resistance of the filling layer. At the moment of blasting, it effectively blocks the rapid escape of high-pressure gas along the hole direction, concentrates the blasting energy in the ore and rock crushing area, reduces the hole punching phenomenon and the generation of flying stones, and thus improves the safety of blasting.

[0023] (2) Effectively reduce dust diffusion

[0024] The clay powder and medium-sized crushed stone in the dust reduction and dust suppression layer form a breathable but not loose medium structure. At the moment of blasting, the clay powder can quickly absorb and adhere to fine dust particles, significantly reducing the pollution of dust diffusion to the working environment. This design plays an important role in improving the blasting construction environment and the safety of operators.

[0025] (3) Highly efficient shock and noise reduction

[0026] Optionally, a shock-absorbing buffer layer of lightweight aggregate and natural fiber is arranged between the dust reduction and dust suppression layer and the top cover layer to absorb energy and reduce the transmission of vibration and noise. Lightweight aggregate and natural fiber form a flexible reinforcement network that can effectively absorb blasting shock waves and vibration energy and reduce the impact of vibration transmission to surrounding buildings or facilities. At the same time, this layer has a significant slow-release effect on blasting noise, reducing environmental noise pollution, and is particularly suitable for mining areas that are sensitive to vibration and noise.

[0027] (4) Optimize construction process and reduce costs

[0028] This application makes full use of zero-cost or low-cost materials such as rock powder and gravel on site, and combines a small amount of modified PU foam material and natural fiber to achieve functional improvement. The construction process is simple and efficient. The PU material is used in small quantities and cures quickly, which significantly improves construction efficiency. The overall cost is lower than that of traditional high-performance materials, and is suitable for large-scale engineering promotion.

[0029] (5) Enhance the controllability of construction quality

[0030] This application uses intelligent monitoring technology to monitor the density of the filling layer, the expansion process of the PU foam material and the curing time in real time, and dynamically captures the blasting dust concentration and vibration amplitude to achieve precise control of the construction process. This dynamic monitoring method not only ensures the stability of the filling quality, but also provides scientific guidance for construction under different geological conditions.

[0031] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings used in the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 This is a process flow chart of a layered composite plugging method for large-diameter blastholes in an open-pit mine in an embodiment of the present application;

[0034] Figure 2 This is a schematic diagram of the layered composite structure of a large-diameter blasthole in an open-pit mine in an embodiment of the present application;

[0035] Explanation of the accompanying drawings: 1. Bottom isolation and stabilization layer; 2. Anti-punchment main layer; 3. Dust reduction and dust suppression layer; 4. Shock absorption and buffer layer; 5. Top covering layer; 6. Explosive layer. DETAILED DESCRIPTION

[0036] The following embodiments of the technical solution of the present application will be described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0038] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0039] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0040] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0041] In open-pit mine blasting, the quality of blasthole filling is directly related to the utilization rate of blasting energy, control of ore rock block size, generation of flying rocks and dust, and vibration. Traditional filling often uses rock powder, crushed stone or sandy materials, which are difficult to meet the multiple needs of density, dust suppression, shock absorption and punching control in large-diameter blastholes at the same time. Mines use clay filling method, sand filling method or clay-sand filling method to plug holes. These filling methods have relatively single materials, their performance is greatly affected by the environment, and their anti-explosion performance is limited. Environmental changes can easily lead to the destruction of the filling structure, affecting the blasting effect. At the same time, these methods have cumbersome operation processes, high requirements for operators, and rely on manual operation, which increases the difficulty of quality control. In addition, when the aperture is large, simple filling is prone to problems such as hole punching, increased flying rocks and unsatisfactory block size; it is difficult to fully compact with pure crushed stone or fine material filling, and rapid pressure relief and dust diffusion are prone to occur at the hole at the moment of blasting; the use of special or high-priced materials will increase construction costs and reduce economic efficiency.

[0042] In order to solve the technical problems of insufficient density, dust diffusion, increased flying rocks and high cost in blasthole filling in open-pit mine blasting, the present application provides a layered composite filling method for large-diameter blastholes in open-pit mines, wherein, by combining low-cost modified polyurethane foam materials with multifunctional layered design, intelligent monitoring and dynamic optimization are achieved during construction, thereby greatly improving the filling quality and blasting effect without significantly increasing costs.

[0043] Please refer to Figure 1 The present application provides a layered composite filling method for large-diameter blastholes in an open-pit mine, comprising the following steps:

[0044] S1. Fill rock powder above the explosive layer 6 to form a bottom isolation and stabilization layer 1;

[0045] S2. Fill large-size gravel above the bottom isolation stabilization layer 1, and inject modified polyurethane foam material to fill the gap to form an anti-punching main layer 2;

[0046] S3. Fill a mixture of clay powder and medium-sized gravel above the anti-punching main layer 2 to form a dust reduction and dust suppression layer 3;

[0047] S4. Fill the top with rock powder and spray water to make the surface slightly crusted to form a top capping layer 5.

[0048] In the technical scheme of the embodiment of the present application, through the layered filling method, the bottom isolation and stabilization layer 1 can effectively prevent the explosive energy from leaking upward, ensuring that the explosive energy is mainly used to crush the ore and rock, thereby improving the utilization rate of the blasting energy; the modified polyurethane foam material in the anti-punching main layer 2 can fill the gaps between the large-size crushed stones to form a high-density structure, effectively preventing the hole punching phenomenon, and at the same time, the composite structure formed by the large-size crushed stones and the polyurethane foam material of the anti-punching main layer 2 can effectively transmit and disperse the blasting energy, which helps to control the block size of the ore and rock, making it more in line with the requirements of subsequent processing; the high density of the anti-punching main layer 2 and the dust reduction and dust suppression layer 3 formed by the mixture of clay powder and medium-size crushed stones can effectively reduce the generation of flying stones and reduce the risk to the surrounding environment and equipment. The clay powder can absorb and fix dust, reduce the diffusion of dust during blasting, improve the working environment, and reduce environmental pollution. The layered composite filling structure of the present application can absorb and disperse the vibration energy generated by blasting, reducing the impact on the surrounding environment and structure. This method utilizes on-site resources and low-cost auxiliary materials, avoids the use of special or high-priced materials, reduces the cost of filling, and improves economic efficiency. In addition, this method has clear steps and is easy to operate. It can complete filling in a short time, improving the safety and efficiency of open-pit mine blasting operations.

[0049] Furthermore, in some embodiments, in step S1 , the thickness of the bottom isolation and stabilization layer 1 is 1.5-2 m.

[0050] In the technical solution of the embodiment of the present application, 100% rock powder (from drilling byproducts) is used for filling. Since rock powder is a zero-cost material on site, it is easy to obtain and compacted after filling to form a basic stable cushion layer 1, isolating the explosives from the air circulation at the orifice, reducing high-pressure gas leakage, improving blasting efficiency, and providing a stable foundation for the upper functional layer to ensure the reliability of the overall structure. The thickness of 1.5 to 2 meters can provide sufficient isolation for the explosive layer 6, ensuring that the gas and shock wave generated by the explosion of the explosive will not easily penetrate the layer, thereby reducing energy loss and improving blasting efficiency.

[0051] Further, in some embodiments, in step S2, the thickness of the anti-punch main layer 2 is 1.5 to 2 m; and / or the particle size of the large-size crushed stone is 30 to 50 mm; and / or the volume ratio of the large-size crushed stone to the modified polyurethane foam material is (80 to 90): (10 to 20).

[0052] In the technical solution of the embodiment of the present application, the thickness of the anti-punching main layer 2 is 1.5 to 2 m, which can provide sufficient strength and stability. The large-size crushed stones form a skeleton structure, and the modified PU foam material fills the gaps between the aggregates and solidifies quickly to construct a high-density plugging layer. This layer can effectively resist the high-pressure gas from rushing out toward the orifice at the moment of blasting, reducing the orifice punching and flying stones, and at the same time, it cooperates with the bottom isolation and stabilization layer 1 to enhance the stability of the overall filling structure. The modified PU foam material has a small amount of use, simple construction and fast curing, which further improves the overall performance of the filling layer.

[0053] Furthermore, in some embodiments, the modified polyurethane foam material is a single-component polyurethane foam material containing 1-3% of silicon dioxide nanoparticles.

[0054] In the technical solution of the embodiment of the present application, 1-3% by mass of silica nanoparticles can improve the bubble stability and compressive strength of the PU material, improve the strength and durability of the filling layer, and optimize the expansion rate to meet the filling requirements of large-diameter blast holes; the modified polyurethane foam material solidifies within a few minutes to tens of minutes after injection, completes expansion and solidification, fills the gaps between large-diameter gravel, and forms a high-density anti-punching main layer 2, thereby significantly reducing the hole punching phenomenon and reducing the probability of flying stones.

[0055] Furthermore, in some embodiments, in step S3, the thickness of the dust reduction and dust suppression layer 3 is 1-1.5 m; and / or the volume ratio of clay powder to medium-sized gravel is (5-15): (85-95).

[0056] In the technical solution of the embodiment of the present application, the thickness of 1 to 1.5 m provides sufficient structural stability, which helps to maintain the integrity of the layer during blasting, prevents damage due to blasting impact, and ensures that the layer structure effectively plays a role in dust reduction and dust suppression during the blasting process. The crushed stone constitutes a basically breathable but not loose medium, and the clay powder has good bonding and adsorption properties. During blasting, the flying fine dust particles can be adhered by the clay, thereby reducing the escape of dust and the pollution of the upper environment. Clay is cheap and abundant in resources. It can effectively absorb the fine dust particles generated during blasting, and a small amount of addition can play a significant dust suppression role. The dust reduction and dust suppression layer 3 works synergistically with the anti-punching main layer 2 to improve the environmental protection level of the blasting operation.

[0057] Furthermore, in some embodiments, the clay powder is at least one of bentonite and common clay; and / or the particle size of the medium-sized crushed stone is 5 to 20 mm.

[0058] In the technical solution of the embodiment of the present application, bentonite is a clay mineral with high water absorption and expansion, which can effectively adsorb and fix dust particles. Ordinary clay may be slightly lower in bonding and adsorption performance than bentonite, but it is low in cost and abundant in resources, and can also meet basic dust reduction needs. 5-20mm medium-sized crushed stone forms a breathable medium, which ensures the air permeability of the layer, reduces the internal and external pressures when the blasting pressure is released, helps the normal release of blasting gas, and prevents the spread of dust.

[0059] Furthermore, in some embodiments, in step S4, the thickness of the top capping layer 5 is 0.5-1 m.

[0060] In the technical solution of the embodiment of the present application, rock powder is used to seal the hole on the top, and water is sprayed to form a crust on the surface, which effectively controls the escape of dust and small particles and reduces the impact on the surrounding environment. This layer makes full use of the on-site rock powder, and the construction is fast and low-cost, which significantly improves the construction economy and environmental protection.

[0061] Furthermore, in some embodiments, a mixture of natural fiber and lightweight aggregate is filled between the dust reduction and dust suppression layer 3 and the top cover layer 5 to form a shock absorbing buffer layer 4 .

[0062] In the technical solution of the embodiment of the present application, the lightweight aggregate is porous and low in density, which can absorb part of the blast shock wave and reduce the vibration and noise transmission. Natural fibers are embedded in the lightweight aggregate to form a flexible reinforcement network, which improves the overall toughness and deformation capacity of this layer and makes the shock absorption effect more significant. Natural fibers are inexpensive, biodegradable, easily available and environmentally friendly, thus achieving the additional function of reducing noise and vibration at a low cost.

[0063] Furthermore, in some embodiments, the thickness of the shock-absorbing buffer layer 4 is 1 to 1.5 m; and / or the volume ratio of natural fiber to the lightweight aggregate is (5 to 10): (90 to 95); and / or the natural fiber is at least one of coconut shell fiber and straw fiber.

[0064] In the technical solution of the embodiment of the present application, the thickness of the shock-absorbing buffer layer 4 can provide effective vibration absorption and buffering effects, and reduce the propagation of blasting vibration waves. The volume ratio of natural fiber to lightweight aggregate can ensure that the buffer layer has sufficient strength and stability and can play a good shock-absorbing effect. The shock-absorbing buffer layer 4 can absorb and disperse the vibration energy generated by the blasting, reduce the damage to the surrounding rock mass and buildings, and reduce vibration to improve the safety of blasting operations and reduce the risk of secondary disasters caused by vibration. The natural fibers used, such as coconut shell fibers, straw fibers, etc., are renewable and environmentally friendly materials, which are beneficial to environmental protection. At the same time, they give the shock-absorbing buffer layer 4 higher toughness and energy absorption characteristics, further reducing blasting vibration and noise. The use of lightweight aggregates such as expanded perlite reduces material costs, simplifies the construction process, and improves economic benefits. The shock-absorbing buffer layer 4 further reduces the spread of dust through the synergistic effect with the top cover layer 5 and the dust reduction and dust suppression layer 3. Each layer of the present application has its specific function, but at the same time it also provides support and protection for the next layer, forming a complementary effect. The material and thickness design of each layer together constitute a stable and reliable filling structure, ensuring the smooth progress of the blasting operation and realizing safe, efficient and environmentally friendly blasting operations.

[0065] Furthermore, in some embodiments, pressure sensors, ultrasonic reflection monitoring devices, thermal imaging equipment and mechanical strength testing equipment are arranged in the anti-punching main layer 2, and dust detectors and vibration sensors are arranged at the orifices and surrounding areas.

[0066] In the technical solution of the embodiment of the present application, in order to ensure the filling quality and blasting effect, intelligent monitoring and construction optimization technology is introduced. By real-time monitoring of key parameters in the filling process and combining dynamic feedback control, the controllability of construction quality and the stability of blasting effect are improved, which specifically includes the following contents:

[0067] (1) Real-time monitoring of density

[0068] During the construction of the filling layer, pressure sensors and ultrasonic reflection monitoring devices are arranged in the anti-punching main layer 2 to measure the internal pressure changes and density distribution of the filling layer respectively. The pressure sensor is used to sense the density changes of the filling material during the filling and compaction process in real time, and the ultrasonic equipment analyzes the uniformity of the filling layer through the echo signal. After the construction of the bottom isolation and stabilization layer 1 is completed, the pressure sensor is started to monitor the filling density of the crushed stone and PU materials during the construction of the anti-punching main layer 2. During the PU foaming and expansion process, the ultrasonic device is combined to capture the dynamic changes of the density over time. When a local low-density area is found, the PU injection amount and foaming rate are adjusted through the feedback system.

[0069] (2) Expansion rate and curing time monitoring

[0070] Use thermal imaging equipment to capture the expansion process and heat distribution of the modified PU material to ensure that the expansion rate and filling uniformity meet the design requirements. Cooperate with mechanical strength testing equipment to measure the strength growth curve of the PU material during the curing process to confirm the final bearing capacity of the filling layer. After the PU foaming begins, use thermal imaging equipment to capture the temperature changes in the foaming area in real time to monitor whether the expansion rate is uniform and fast. After the PU material is initially cured, start the mechanical strength detection device to detect the initial strength of the filling layer, and record the curing time for the strength to grow to the design requirements. If the expansion rate is found to be too fast or too slow, compensate by adjusting the pressure or injection volume of the grouting equipment. When the curing time exceeds the design standard, evaluate the proportion of the PU material and the ambient temperature and humidity, and optimize the construction parameters of the next hole.

[0071] (3) Environmental effect monitoring

[0072] Dust detectors and vibration sensors are deployed to record dust concentration and vibration amplitude in real time during blasting. Dust detectors are placed at the orifice and surrounding areas to quantitatively analyze changes in PM2.5 and PM10 concentrations based on the principle of light scattering. Vibration sensors are placed at key points around the blasting site to monitor the amplitude, frequency and propagation range of blasting vibrations. Before blasting, the dust detector presets a warning threshold and records the instantaneous peak value of dust concentration during blasting in real time. The vibration sensor is connected to the data acquisition equipment to record vibration signals during blasting, quantify vibration amplitude and propagation path. After the blasting is completed, an environmental impact data report is generated, including a dust concentration change curve and a vibration propagation range map, which provides a scientific basis for construction under different geological conditions and optimizes subsequent filling and blasting parameters through a feedback control mechanism.

[0073] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used without specifying the manufacturer are all conventional products that can be obtained commercially.

[0074] Example 1

[0075] This embodiment provides a layered composite filling method for a large-diameter blasthole in an open-pit mine. The diameter of the blasthole in the open-pit mine is about 310 mm and the depth is about 15 m. Figure 2 As shown, the specific steps include:

[0076] S1. Fill 1.5m of rock powder (drilling by-product) above the 8.5m charging depth, and form a bottom isolation and stabilization layer 1 through slight compaction; this layer effectively isolates the explosives from the air circulation at the hole mouth, reduces the leakage of blasting energy along the hole mouth direction, and provides stable support for the upper filling layer.

[0077] S2. Fill 1.5m of large-size gravel above the bottom isolation and stabilization layer 1, accounting for about 85% of the volume, and inject modified PU foam material to fill the gaps. After solidification, a high-density anti-punching main layer 2 is formed. The modified PU foam material contains 3% of silica nanoparticles; this layer effectively resists the impact of high-pressure gas at the moment of blasting, significantly reducing the hole punching phenomenon and flying stones; pressure sensors and ultrasonic equipment are arranged in the hole to dynamically monitor the density and uniformity of the filling layer, and automatically feedback and adjust the amount of filling material used when a low-density area is found; thermal imaging equipment is used to capture the expansion process of the modified polyurethane foam material, and the curing strength and bearing capacity of the filling layer are confirmed by mechanical strength testing equipment.

[0078] S3. Fill 1m3 of a mixture of 90% medium-sized crushed stone and 10% bentonite on the anti-blowout main layer 2 to form a dust reduction and dust suppression layer 3; this layer structure can absorb fine dust particles during blasting, significantly reduce dust escape, and improve the blasting environment.

[0079] S4. A mixture of 92% expanded perlite and 8% coconut shell fiber is added to form a 1m shock-absorbing buffer layer 4; this layer absorbs shock wave energy, releases vibration slowly, and reduces the transmission of blasting noise, which is particularly suitable for construction in sensitive areas.

[0080] S5. Fill the top 0.5m with rock powder and spray with clean water to make the surface microcrust to form a top capping layer 5; this layer structure can effectively seal the hole, prevent the escape of small particles, and further reduce dust pollution; dust detectors and vibration sensors are installed at the hole and surrounding areas to record the blasting dust concentration and vibration amplitude in real time and evaluate the impact of blasting on the surrounding environment.

[0081] Test results:

[0082] In the actual blasting test, the blastholes using the above-mentioned layered composite filling method were compared with the traditional sand and gravel filling method, and the results are as follows:

[0083] (1) The hole punching phenomenon is significantly reduced, and the proportion of unsealed holes is reduced from 80% to 20%.

[0084] (2) Blasting dust concentration (PM2.5) was reduced by 40% from 250 μg / m 3 Reduced to 150 μg / m 3 .

[0085] (3) The vibration amplitude is reduced by 20%, from 50 mm / s to 40 mm / s.

[0086] (4) The ore block size distribution is more uniform, with the average block size reduced from 30 cm to 25 cm, reducing the need for secondary crushing.

[0087] This application combines modified polyurethane foam materials with multifunctional layered design to achieve intelligent monitoring and dynamic optimization during construction, greatly improving the filling quality and blasting effect without significantly increasing costs. Each layer of the filling structure has a specific function and provides support and protection for the next layer to form a complementary effect. The material and thickness design of each layer together constitute a stable and reliable filling structure, ensuring the safety, efficiency and environmental friendliness of the blasting operation.

[0088] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A layered composite filling method for large-diameter blastholes in open-pit mines, characterized in that: The following steps are involved: S1. Fill rock powder above the explosive layer to form a bottom isolation and stabilization layer; S2. Fill large-size gravel above the bottom isolation stabilization layer and inject modified polyurethane foam material to fill the gap to form an anti-punching main layer; S3. Fill a mixture of clay powder and medium-sized gravel above the anti-punching main layer to form a dust reduction and dust suppression layer; S4. Fill the top with rock powder and spray water to make the surface slightly crusted to form a top capping layer.

2. The layered composite filling method for large-diameter blastholes in open-pit mines according to claim 1 is characterized in that: In step S1, the thickness of the bottom isolation and stabilization layer is 1.5-2 m.

3. The layered composite filling method for large-diameter blastholes in open-pit mines according to claim 1 is characterized in that: In step S2, the thickness of the anti-punching main layer is 1.5 to 2 m; and / or The particle size of the large-size crushed stone is 30 to 50 mm; and / or The volume ratio of the large-size crushed stone to the modified polyurethane foam material is (80-90):(10-20).

4. The layered composite filling method for large-diameter blastholes in open-pit mines according to claim 3 is characterized in that: The modified polyurethane foam material is a single-component polyurethane foam material containing 1-3% silicon dioxide nanoparticles.

5. The layered composite filling method for large-diameter blastholes in open-pit mines according to claim 1 is characterized in that: In step S3, the dust reduction and dust suppression layer has a thickness of 1 to 1.5 m; and / or The volume ratio of the clay powder to the medium-sized crushed stone is (5-15):(85-95).

6. The layered composite filling method for large-diameter blastholes in open-pit mines according to claim 5 is characterized in that: The clay powder is at least one of bentonite and common clay; and / or The particle size of the medium-sized crushed stone is 5 to 20 mm.

7. The layered composite filling method for large-diameter blastholes in open-pit mines according to claim 1 is characterized in that: In step S4, the thickness of the top cover layer is 0.5-1 m.

8. The layered composite filling method for large-diameter blastholes in open-pit mines according to claim 1 is characterized in that: A mixture of natural fiber and lightweight aggregate is filled between the dust reduction and dust suppression layer and the top covering layer to form a shock absorbing and buffering layer.

9. The layered composite filling method for large-diameter blastholes in open-pit mines according to claim 8, characterized in that: The thickness of the shock absorbing buffer layer is 1 to 1.5 m; and / or The volume ratio of the natural fiber to the lightweight aggregate is (5-10): (90-95); and / or The natural fiber is at least one of coconut shell fiber and straw fiber.

10. The layered composite filling method for large-diameter blastholes in open-pit mines according to claim 1, characterized in that: It also includes arranging pressure sensors, ultrasonic reflection monitoring devices, thermal imaging equipment and mechanical strength testing equipment in the anti-punching main layer, and arranging dust detectors and vibration sensors at the hole opening and surrounding areas.

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