Surface mine high-temperature blasting structure and method based on rapid phase change cooling and modular charging

Abstract

The invention relates to a surface mine high-temperature blasting structure and method based on rapid phase change cooling and modular charging, and solves the problem of low efficiency existing in an existing high-temperature blasting technology. Comprising a high-temperature blast hole, a modular charging unit, a detonating cord, a detonating bomb and a blast hole filler, the modular charging unit is formed by uniformly mixing a paraffin-based composite material and an explosive in proportion and then packaging, and is used for blasting operation in a high-temperature environment; the paraffin-based composite material is granular and is prepared by mixing paraffin and graphite according to a certain weight ratio, and the paraffin-based composite material can absorb heat through solid-liquid phase change in a high-temperature environment, reduce the temperature in a blast hole and maintain a stable low-temperature environment, so that the safety and stability of an explosive and a detonating device are ensured; the modular charging unit is packaged by high-density polyethylene, and forms a complete blasting system with a detonating cord, a detonating device and a blast hole filler. The safety and efficiency of high-temperature blasting operation can be remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-temperature blasting in open-pit mines, and particularly relates to an open-pit mine high-temperature blasting structure and method based on rapid phase change cooling and modular charge loading. Background Art

[0002] During the open-pit mine mining operation, the high-temperature environment has an adverse impact on the safety and blasting effect of the blasting operation. The temperature in the blast hole is relatively high (40 - 80 °C), which can cause the attenuation of explosive performance, the failure of the initiation system, and even lead to explosion accidents. Among them, high-temperature blasting refers to the blasting operation where the bottom temperature of the blast hole is between 40 - 80 °C. According to the "Code for Blasting Safety (GB6722 - 2014)" in China, when the high-temperature blasting temperature is lower than 80 °C, heat-resistant blasting equipment or heat insulation protection measures should be selected; when the temperature exceeds 80 °C, heat insulation protection measures must be taken for the blasting equipment.

[0003] The application fields of high-temperature blasting operations mainly include high-temperature rock blasting, spontaneous combustion coal seam treatment, high-temperature sulfide ore mining, and oil and gas well repair projects, etc. The existing high-temperature blasting treatment technologies mainly focus on the following three categories: blast hole cooling (including water injection cooling, grouting cooling, and colloid cooling), heat-resistant blasting equipment (using heat-resistant explosives, initiation components, and heat insulation protection materials), and special blasting safety technologies (improving the blasting safety in high-temperature environments through special devices and methods). Currently, the treatment methods for high-temperature blasting have been reflected in some technologies, but there are still the following deficiencies:

[0004] 1. Water injection cooling technology. For example, the patent (CN 106643354 B) "A high-temperature fire area safe and rapid blasting construction device and method" uses continuous water injection for cooling to solve the stability problem of blasting agents in high-temperature environments. Water injection easily leads to too high humidity in the blast hole, causing problems such as hole wall collapse and explosive immersion failure, and the cooling effect is significantly affected by the ambient temperature, blast hole depth, and water injection volume, and the cooling persistence and stability are poor.

[0005] 2. Water-absorbing resin-based material technology. For example, the patent (CN 111780636 B) "A device and method for high-temperature blasting in open-pit mines" adopts the method of mixing water particles with explosives, and the water particles made of water-absorbing resin are used to reduce the blast hole temperature to improve blasting safety. The water-absorbing resin particles rely on water evaporation to achieve cooling, and the cooling effect is short-lived and significantly affected by humidity, and it cannot maintain a stable cooling effect under continuous high-temperature conditions.

[0006] 3. Heat insulation sleeve device. As described in the patent (CN 113154971 B) "A heat insulation device for high-temperature blasting and blasting method", the heat insulation sleeve and cooling water are used to isolate the impact of high temperature on explosives. The cooling water is prone to evaporation and exhaustion in a high-temperature environment, resulting in unstable heat insulation effect; the prefabrication and plugging operations of the heat insulation sleeve are complex, and the construction time is relatively long.

[0007] 4. Heat insulation technology for initiation device. As described in the patent (105091679A) "An initiation device for high-temperature fire area and its assembly method", heat-absorbing substances are used to wrap explosives and initiation elements to isolate high temperature. Its multi-layer structure and snap connection design increase the assembly steps and on-site construction time, and have relatively high technical requirements for operators. Summary of the Invention

[0008] The present invention proposes an open-pit mine high-temperature blasting structure and method based on rapid phase change cooling and modular charge loading. The rapid phase change endothermic cooling is realized through a paraffin-based composite material, and combined with the modular charge loading design, the construction process is simplified, the blasting efficiency and safety are improved, the problems of poor cooling persistence, high construction complexity and insufficient environmental adaptability existing in the existing high-temperature blasting technology are solved, and the construction efficiency is improved at the same time.

[0009] The technical principle of the present invention is to absorb heat in a high-temperature blast hole through the phase change characteristics of the paraffin-based composite material and maintain a stable low-temperature environment, so as to protect the performance stability of explosives and initiation equipment. Combined with the modular charge loading design, the integration of loading and cooling is realized, and the construction process is simplified by prefabricated modular charge loading, and the safety and efficiency of high-temperature blasting operations are improved.

[0010] The present invention is realized by the following technical solutions:

[0011] An open-pit mine high-temperature blasting structure based on rapid phase change cooling and modular charge loading, comprising a high-temperature blast hole, a modular charge loading unit, a detonating cord, an initiation cartridge and a blast hole filler; the modular charge loading unit is formed by uniformly mixing a paraffin-based composite material and explosives in proportion and then encapsulating them, and is used for blasting operations in high-temperature environments; the paraffin-based composite material is granular and is made by mixing paraffin and graphite in a certain weight ratio. The paraffin-based composite material can absorb heat through solid-liquid phase change in a high-temperature environment, reduce the temperature in the blast hole and maintain a stable low-temperature environment, thereby ensuring the safety and stability of explosives and initiation equipment; the modular charge loading unit is encapsulated with a high-density polyethylene (HDPE) bag and is stacked and placed in the blast hole during construction, forming a complete blasting system with the detonating cord, initiation equipment and blast hole filler.

[0012] Preferably, the mixing ratio of the paraffin-based material and the explosives is adjusted according to the temperature of the high-temperature blast hole. By reasonably adjusting the ratio, the balance between the cooling effect and the blasting performance can be ensured.

[0013] Preferably, the hole pattern parameters of the high-temperature blast holes are designed according to the quantity and proportion of the modular charge units: when the paraffin-based material content is relatively high, the hole spacing and row spacing are appropriately reduced to ensure the concentrated release of blasting energy; when the paraffin-based material content is relatively low, the hole pattern parameters can be appropriately increased to optimize the explosive utilization rate.

[0014] Preferably, the explosive is a water-resistant bulk material that can be normally detonated after being mixed with the paraffin-based material and can also be normally detonated in the presence of a small amount of water or high-temperature steam in the blast holes.

[0015] Preferably, both the detonating cartridge and the detonating cord have certain high-temperature resistance, and the detonating network composed of them is designed for irreversible detonation to ensure the stability and safety of the detonation process. The blast hole stuffing uses ordinary crushed stones or sandy soil, and its maximum particle size is less than or equal to the blast hole radius, which is used to block the upper part of the charge module to improve the blasting energy utilization rate.

[0016] The present invention also relates to an open-pit mine high-temperature blasting method based on rapid phase change cooling and modular charging, and the specific construction method includes the following steps:

[0017] Step 1: Drill holes in the blasting area of the open-pit mine, use a drill rig to arrange blast holes in the blasting area, and the depth and diameter of the blast holes are carried out according to the blasting design requirements;

[0018] Step 2: Measure the temperature of the first drilled blast hole, use a high-temperature-resistant temperature measurement probe to measure the temperature at the bottom of the blast hole, and record the data. If the blast hole temperature exceeds 40 °C, it is marked as a high-temperature blast hole;

[0019] Step 3: Measure the temperature of each blast hole after drilling is completed, and mark the high-temperature blast holes;

[0020] Step 4: Adjust the hole pattern parameters of the blast holes according to the measured temperature. When the measured blast hole temperature is relatively high (60 - 80 °C), the hole spacing and row spacing are appropriately reduced to ensure the concentration of blasting energy; when the measured temperature is relatively low (40 - 60 °C), the hole pattern parameters are appropriately increased to improve the explosive utilization rate; the final hole pattern parameters are adjusted according to the actual blast hole distribution and fixed before construction;

[0021] Step 5: Select a suitable modular charge unit 2 according to the measured blast hole temperature;

[0022] Step 6: Load a detonating cartridge into the bottom of the high-temperature blast hole, place the detonating cartridge at the bottom of the high-temperature blast hole, and connect it to the surface detonating network through a detonating cord to ensure the connectivity between the detonating cartridge and the surface detonating network;

[0023] Step 7: Load the modular charge units, layer by layer load the modular charge units to the first designed height (usually 1 / 4 of the hole depth), and specifically adjust according to the blast hole depth;

[0024] Step 8: Load the intermediate detonator. After the first-layer modular charge unit is loaded, place the second detonator on top of the first-layer modular charge unit; the second detonator is connected to the surface through an independent detonating cord and kept in contact with the upper-layer modular charge unit. The multi-layer detonation design is used to ensure the integrity and reliability of the blasting and reduce the risk of misfires.

[0025] Step 9: Continue loading the modular charge unit. Based on the intermediate detonator, continue loading the modular charge unit into the blast hole until the designed charge height is reached.

[0026] Step 10: Plug the blast hole. Use crushed stone or sand as the plugging material and plug layer by layer to the top of the blast hole to improve the utilization rate of blasting energy and ensure the stability of the detonation network.

[0027] Step 11: Connect the detonation network. Connect the exposed end of the detonating cord to the surface detonation network and check the network connectivity; use an irreversible detonation network design during connection to ensure stable signals during detonation.

[0028] Step 12: After the construction of all high-temperature blast holes is completed, the construction personnel quickly withdraw to the safe area and set up a warning line.

[0029] Step 13: After the blasting commander confirms that there is no abnormality in safety, issue the detonation order: Cut off the power supply in time after the detonation network is activated; separate the main line from the detonator to ensure operation safety.

[0030] Step 14: Inspect the blast area. After the blasting is completed, check the blasting effect and remaining problems, and cancel the warning line after confirming that there is no abnormality in the blast area.

[0031] The present invention provides an efficient and low-cost high-temperature blasting method, which solves the problems of explosive performance attenuation and construction complexity in high-temperature environments, and has significant safety and economic advantages, and is applicable to high-temperature fire area blasting operations in various open-pit mines. The specific effects include:

[0032] (1) High safety: The paraffin-based material absorbs heat through solid-liquid phase change, reducing the temperature of the high-temperature blast hole to within the safe range of the explosive and detonating equipment. The temperature persistence is strong and less affected by the external environment.

[0033] (2) High efficiency: The modular charge unit is premixed and encapsulated, and is directly placed into the blast hole during construction, eliminating complex loading steps, with higher construction efficiency and controllable material consumption.

[0034] (4) Wide applicability: The construction process is simple, applicable to high-temperature fire areas of 40 - 80 °C, covering a variety of open-pit mine blasting scenarios.

[0035] (5) Environmental friendliness: The paraffin-based material has no residue, explodes synchronously with the explosive, and causes no environmental pollution. Description of the Drawings

[0036] Figure 1 It is a schematic diagram of the high-temperature hole charging structure of the present invention.

[0037] Wherein: 1 - high-temperature blast hole; 2 - modular charging unit; 3 - bottom-hole initiating cartridge; 4 - bottom-hole detonating cord; 5 - intermediate initiating cartridge; 6 - intermediate detonating cord; 7 - hole plugging material Detailed Embodiment

[0038] To better describe the present invention, the following further describes a high-temperature open-pit mine blasting method based on rapid phase change cooling and modular charging of the present invention with reference to the drawings.

[0039] Embodiment:

[0040] As Figure 1 shown, the hole charging structure of the present invention includes a high-temperature blast hole 1, a modular charging unit 2, a bottom-hole initiating cartridge 3, a bottom-hole detonating cord 4, an intermediate initiating cartridge 5, an intermediate detonating cord 6, and a hole plugging material 7. The high-temperature blast hole 1 has an explosive filling area and a plugging material filling area. The explosive filling area is divided into upper and lower layers for loading the modular charging unit 2 and initiating devices, and the plugging material filling area is used to seal the top of the modular charging unit.

[0041] Preferably, the modular charging unit 2 is a prefabricated unit in which a paraffin-based composite material and an explosive are uniformly mixed according to the following weight ratio according to the high-temperature hole temperature: when the hole temperature is 40 - 60 °C, the weight ratio is 1:5 to 1:4; when the hole temperature is 60 - 80 °C, the weight ratio is 1:4 to 1:3. The modular charging unit 2 is a cylindrical bagged unit with a diameter of 75 - 85% of the hole diameter, ensuring that it can be smoothly placed into the hole and leaving enough space for placing the detonating cord. The unit height is about 0.5 m and is encapsulated with high-density polyethylene material.

[0042] Preferably, the main components of the paraffin-based composite material are paraffin (accounting for 80% - 90%) and graphite (accounting for 10% - 20%). Graphite, a heat-conducting material, is incorporated into paraffin to enhance the heat transfer efficiency and accelerate the cooling rate. The particle size of the paraffin-based composite material is 1 - 3 mm, and it cools down by absorbing heat through solid-liquid phase change. The cooling duration is 1 - 3 hours, and the specific time depends on the initial hole temperature, paraffin content, and hole depth.

[0043] The charging steps include:

[0044] Step 1: Design the preliminary hole pattern parameters according to the blasting area.

[0045] Step 2: Drill holes in the blasting area according to the blasting design requirements. The hole depth of the blast hole is 12 m and the diameter is 150 mm.

[0046] Step 3: Measure the temperature inside the first drilled blast hole and adjust the hole pattern parameters according to the temperature record (if necessary).

[0047] Step 4: After the drilling is completed, measure the temperature of each blast hole and mark the high-temperature blast hole 1 (above 40 °C).

[0048] Step 5: Select a suitable modular charge unit 2 according to the measured blast hole temperature.

[0049] Step 6: Install a bottom detonating cartridge 3 at the bottom of the high-temperature blast hole 1. The bottom detonating cartridge 3 is connected to the bottom detonating cord 4, and the other end of the bottom detonating cord 4 is connected to the surface initiation network.

[0050] Step 7: Install the modular charge unit 2 into the high-temperature blast hole 1 until the first layer of charge design height (the filling height is 3 m).

[0051] Step 8: Place an intermediate detonating cartridge 5 on top of the first layer of modular charge unit 2 and connect the intermediate detonating cord 6. The other end of the intermediate detonating cord 6 is connected to the surface initiation network.

[0052] Step 9: Continue to fill the high-temperature blast hole 1 with the modular charge unit 2 until the charge design height is reached (the filling height is 4 m).

[0053] Step 10: Use crushed stone or sand as the blast hole filler 7. The maximum particle size does not exceed the radius of the blast hole. Fill it layer by layer to the top of the blast hole. The filling height is 6 m to complete the charging.

[0054] During the blasting operation, after checking the initiation network, all construction personnel evacuate to the safe area, and detonate the bottom detonating cartridge 3 and the intermediate detonating cartridge 5 simultaneously through the surface initiation network to ensure the success and overall effect of the blasting.

Claims

1. A high-temperature blasting structure for open-pit mines based on rapid phase change cooling and modular charging, characterized by: Including high temperature A blasthole, a modular charge unit, a detonating cord, a detonating bomb and a blasthole filling material; the high-temperature blasthole has an explosive filling area and a filling material filling area, wherein the explosive filling area is divided into at least two layers for loading modular charge units and detonating cords, detonating bombs and other detonating equipment, and each layer of the explosive filling area is equipped with a detonating bomb at the bottom, which is connected to the surface detonating network through the detonating cord; the blasthole filling material in the filling material filling area is used to block the top of the modular charge unit.

2. According to claim 1, a high-temperature blasting structure for open-pit mines based on rapid phase change cooling and modular charging is characterized by: The modular charge unit is a prefabricated unit formed by packaging a paraffin-based composite material and explosives uniformly mixed in proportion according to the high-temperature blasthole temperature.

3. The open-pit mine high-temperature blasting structure based on rapid phase change cooling and modular charging according to claim 2 is characterized by: When the blast hole temperature is 40-60°C, the weight ratio of the paraffin-based composite material to the explosive is 1:5 to 1:4; when the blast hole temperature is 60-80°C, the weight ratio of the paraffin-based composite material to the explosive is 1:4 to 1:

3.

4. The open-pit mine high-temperature blasting structure based on rapid phase change cooling and modular charging according to claim 1 is characterized by: The modular charge unit is packaged with high-density polyethylene (HDPE) material and is stacked and placed in the blast hole during construction, forming a complete blasting system with detonating cords, detonating equipment and blast hole fillings.

5. The open-pit mine high-temperature blasting structure based on rapid phase change cooling and modular charging according to claim 1 is characterized by: The modular charge unit is a cylindrical bagged unit, and its diameter is 75-85% of the diameter of the blast hole.

6. The open-pit mine high-temperature blasting structure based on rapid phase change cooling and modular charging according to claim 2 or 3 is characterized by: The paraffin-based composite material is in granular form and is made by mixing paraffin and graphite in a certain weight ratio, wherein the paraffin accounts for 80%-90% and the graphite accounts for 10%-20%. The particle size of the paraffin-based composite material is 1-3 mm.

7. The open-pit mine high-temperature blasting structure based on rapid phase change cooling and modular charging according to claim 1 is characterized by: The explosive is a water-resistant bulk material, and the blasthole filling material is ordinary crushed stone or sand, and the maximum particle size of the blasthole filling material is less than or equal to the blasthole radius.

8. The open-pit mine high-temperature blasting structure based on rapid phase change cooling and modular charging according to claim 1 is characterized by: The detonating bomb and the detonating cord both have high temperature resistance, and the detonating network formed together is designed for irreversible detonation.

9. The open-pit mine high-temperature blasting structure based on rapid phase change cooling and modular charging according to claim 1 is characterized by: The designed height of the first layer of the explosive filling area is 1 / 4 of the hole depth.

10. A high temperature blasting method for open pit mines based on rapid phase change cooling and modular charging, comprising the following steps: Step 1: Drill holes in the blasting area of ​​the open-pit mine, and use a drilling rig to arrange blast holes in the blasting area. The depth and diameter of the blast holes shall be in accordance with the blasting design requirements; Step 2: Measure the temperature of the first drilled blasthole by using a high temperature resistant temperature measuring probe to measure the bottom temperature of the blasthole and record the data. If the blasthole temperature exceeds 40°C, mark it as a high temperature blasthole. Step 3: After drilling, measure the temperature of each blasthole and mark the high-temperature blastholes; Step 4: Adjust the hole mesh parameters according to the measured temperature. When the measured hole temperature is 60-80°C, appropriately reduce the hole spacing and row spacing to ensure the concentration of blasting energy; when the measured temperature is 40-60°C, appropriately increase the hole mesh parameters to improve the utilization rate of explosives; the final hole mesh parameters are adjusted according to the actual hole distribution and fixed before construction; Step 5: Select an appropriate modular charge unit according to the measured borehole temperature; Step 6: Load the detonator into the bottom of the high-temperature blasthole, place the detonator into the bottom of the high-temperature blasthole, and connect it to the surface detonation network through the detonating cord to ensure that the detonator maintains connectivity with the surface detonation network; Step 7, loading the modular charge unit, loading the modular charge unit layer by layer to the first layer design height, the first layer design height is adjusted according to the blasthole depth; Step 8: Load the intermediate detonator. After the first layer of modular charge units is loaded, place the second detonator on top of the first layer of modular charge units. The second detonator is connected to the ground through an independent detonating cord and keeps in contact with the upper modular charge units. The multi-layer detonation design is used to ensure the integrity and reliability of the blast and reduce the risk of duds. Step 9, continue to load the modular charge unit, and continue to load the modular charge unit into the blast hole on the basis of the intermediate detonator until the designed charge height is reached; Step 10: Fill the blastholes, using crushed stone or sand as fillers, filling them layer by layer to the top of the blastholes to improve the utilization rate of blasting energy and ensure the stability of the detonation network; Step 11, connect the detonation network, connect the exposed end of the detonating cord to the surface detonation network, and check the network connectivity; use an irreversible detonation network design when connecting to ensure that the signal is stable during the detonation process; Step 12: After all high-temperature blasthole construction is completed, the construction workers quickly evacuate to a safe area and set up a cordon. Step 13: After the blasting commander confirms that everything is safe and normal, he issues a detonation command: cut off the power supply in time after the detonation network is started; separate the main line from the detonator to ensure safe operation; Step 14: Check the blasting area. After the blasting is completed, check the blasting effect and residual problems. After confirming that there is no abnormality in the blasting area, remove the cordon.

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