A method for reducing dust by blasting water mist curtain in open-pit mine

Abstract

The application discloses an open-pit mine blasting dust explosion water mist curtain dust falling method and relates to the technical field of mine blasting, which comprises the following steps: water mist curtain generating position design, arrangement of detonators and detonating cords, arrangement and adjustment of water bags, water mist generation and dust falling, and effect observation; according to the generation and expansion characteristics of blasting gun smoke and dust clouds, the water bags are arranged in front of the upper part of the step and the direction of the designed initiation zero point; under the condition of guaranteeing the safety criterion of the blasting area initiation network, the size of the designed explosion water bag, the water mist convergence and throwing direction and the precise initiation exciting time are designed; the water bags are excited in real time in the process of formation of the blasting gun smoke and the dust clouds, the explosion water mist field covering the whole blasting area and the mushroom dust cloud throwing range is formed, the blasting mushroom dust cloud is intercepted and wholly coated, the atomized water field is used for synchronous and real-time interception, in-situ adsorption, gun smoke dilution and neutralization and dust capture and treatment, additional blast holes do not need to be constructed, the range of action is wide, and the dust falling effect is excellent.

Description

Technical Field

[0001] This invention relates to the field of mining blasting technology, and in particular to a method for generating a water mist curtain to suppress dust during open-pit mine blasting. Background Technology

[0002] Open-pit mining areas and spoil heaps cover a wide area. Spoil heaps, mining platforms, transport roads, and the process of loading rocks with electric shovels all generate a large amount of dust. Currently, this type of dust can be basically controlled by greening and consolidating spoil heaps and by spraying water on transport roads, mining platforms, and during loading. However, for the main dust source of open-pit mining—blasting dust—due to its instantaneous nature, high concentration, and rapid diffusion, traditional water spraying cannot be implemented simultaneously, so it is still ineffective in preventing blasting mushroom dust clouds.

[0003] According to measurements from foreign open-pit mines, 90% of open-pit mine dust comes from mushroom dust clouds generated by blasting. Preliminary statistics from domestic metallurgical mines also show that open-pit blasting dust accounts for more than 80% of total mining dust. Blasting fumes are characterized by high dust concentration, extremely fast diffusion speed, and large dust dispersion range. They are generated instantaneously during the rock-breaking process of blasting, making them extremely difficult to control. In addition, many mines have now entered a deep-pit mining state with limited underground working space, which objectively requires the rapid elimination of blasting fumes. Based on the above actual conditions, if the traditional experience model for handling blasting dust in large open-pit mines that are not arid and are deep-pit mines is applied and allowed to dissipate freely, it will inevitably cause high concentrations of dust and fumes to harm the air intake systems of various workers and major production equipment in the mine pit. The high incidence of silicosis among workers and the high failure rate of operating equipment are also common phenomena.

[0004] In traditional iron ore blasting dust suppression methods, water spraying and mine water cannons cannot be implemented close to the blasting area due to safety requirements. Ground watering and sealing blast holes with water bags only have local effects and the dust suppression effect is not obvious. Therefore, this invention proposes a method for generating a water mist curtain to suppress dust from open-pit mine blasting in order to solve the problems existing in the prior art. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to propose a method for dust suppression by generating a water mist curtain during open-pit mine blasting. This method solves the problems of traditional iron mine blasting dust suppression methods, which are limited by safety requirements preventing water spraying and mine water cannons from approaching the blasting area, while ground watering and sealing blast holes with water bags only have localized effects and are not very effective in reducing dust.

[0006] To achieve the objective of this invention, the invention is implemented through the following technical solution: a method for generating a water mist curtain to suppress dust from open-pit mine blasting, comprising the following steps:

[0007] Step 1: Based on the actual blasting penetration conditions, design the placement and quantity of water bags, as well as the range and direction of the water mist spray;

[0008] Step 2: Level the site for water-filled bags and lay the detonating cord, which will be detonated by an electronic detonator, along the length of the site in the middle.

[0009] Step 3: Lay water bags at the designed location, install the water mist spray control device, and adjust the opening range and direction of the control device;

[0010] Step 4: After the blast zone is detonated, the detonating cord is detonated by an electronic detonator, forming an explosive water mist field that blocks the slope and covers the upper part of the blast zone, thereby achieving dust suppression in the blast zone.

[0011] Step 5: The dust suppression effect in the blast area was observed on-site using DIC, and the dust concentration in the blast area was measured on-site using an FCS-30 dust sampler to evaluate the dust suppression effect of the explosion water mist on the blast area after detonation.

[0012] Further improvements are made in the following aspects: In step one, regarding the placement and quantity of water bags, for open-pit mining bench blasting areas, 1 to 2 water bags are designed on the lower part of the bench in front of the bench slope, with a spacing of 6 to 8 meters between the water bags, and explosive water bags are placed at a spacing of 14 to 16 meters along the direction of the blasting area within the bench blasting area.

[0013] A further improvement is made in the following: In step one, regarding the placement and number of water bags, for the trench blasting area, no water bags are placed at the trench opening, and one water bag is placed on each of the other three sides, placed 8m away from the outer edge of the trench blasting area.

[0014] Further improvements are made in the following aspects: In step one, the water mist spray range and direction should be concentrated on the lower part of the step slope and the outer edge of the trench blasting area, and the direction should be vertically upward or inclined towards the blasting area to play an interception role.

[0015] A further improvement is made in the following: In step one, the water mist spray range and direction should be wider and more diffused in all directions at the middle position of the two rows of boreholes, so as to cover the area.

[0016] A further improvement is made in step two, where the width of the site is equal to the diameter of the water bag, and the site is leveled to prevent large pieces and sharp objects from entering.

[0017] A further improvement is made in step two, where the detonating cord is placed along its length in the middle of the leveled site.

[0018] A further improvement is made in step three, where the water bag is laid along the detonating cord so that the detonating cord is located directly below the water bag.

[0019] A further improvement is made in step three, where the water mist spray control device is placed on both sides of the water bag, one on each side, and the spray range and angle of the water mist are controlled by adjusting the spacing and angle.

[0020] A further improvement is made in step three, where the water mist spray control device consists of two wooden boards and an angle adjustment hinge to achieve angle adjustment.

[0021] A further improvement is that, in step three, the water bag is a hollow tube bag made of polyethylene plastic film with a diameter of 300-350mm, and is filled with water.

[0022] A further improvement is made in step four, where the activation time of the two rows of water bags in front of the stepped blast zone is determined based on the initial velocity of the broken rock, the projection angle, and the distance between the water bags and the slope bottom line. The delayed activation time t after the exploding water bags are detonated at the blast hole can be determined by the following formula:

[0023] t = 0.89716 - 0.1055L + 0.00985L 2 -1.2(s), L∈(11,31)

[0024] L is the horizontal distance (m) from the detonation point of the front row of the exploding water bag.

[0025] A further improvement is that, in step four, the explosive water bags arranged along the direction of the blast zone within the stepped blast zone trigger the electronic detonators to detonate synchronously with the last row of blast holes corresponding to the water bags.

[0026] A further improvement is made in step four, where the detonating cord core is RDX or TAIAN, the charge is 12.0-14.0 g / m, and the electronic detonator is connected in parallel to the overall detonation network of the blast zone to form a complete parallel detonation network.

[0027] The beneficial effects of this invention are as follows: Based on the generation and expansion characteristics of blasting fumes and dust clouds, this invention deploys a corresponding number and type of water bags on the upper part of the step, in front of the designed detonation zero point direction. Under the condition of ensuring the safety of the detonation network in the blasting area, and based on the generation characteristics of blasting fumes and dust clouds, the invention designs the fixed size of the explosive water bags and the precise detonation time. During the formation of blasting fumes and dust clouds, the water bags are activated in real time to form an explosive water mist field covering the entire blasting area and the mushroom dust cloud within the throwing range. This field completely envelops the blasting mushroom dust cloud, implementing simultaneous, real-time, on-site adsorption, fume dilution and neutralization, and dust capture and control through the atomized water field. It has a wider range of effects and excellent dust reduction effect, and is worthy of widespread promotion and application. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the process for the open-pit mine blasting dust dust generation water mist curtain dust suppression method of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure and arrangement of the water mist curtain spray control device of the present invention;

[0030] Figure 3 This is a schematic diagram of the design for precise hole-by-hole detonation in the blast zone and the generation and dust suppression of water mist in the explosion zone according to Embodiment 1 of the present invention.

[0031] Figure 4 This is a real-world illustration of the dust suppression effect of an explosion-induced water mist curtain in Embodiment 1 of the present invention;

[0032] Figure 5 This is a diagram illustrating the explosion effect of water mist curtain dust suppression in Embodiment 1 of the present invention.

[0033] Figure 6 This is a schematic diagram of the dust suppression test explosion zone layout according to Embodiment 2 of the present invention;

[0034] Figure 7 This is a real-world diagram of water mist generation and dust suppression in the explosion zone according to Embodiment 2 of the present invention;

[0035] Figure 8 This is a schematic diagram of the distribution of ore and rock in the test blasting area and the location of the borehole in Embodiment 3 of the present invention;

[0036] Figure 9 This is a real-world diagram of water mist generation and dust suppression in the explosion zone according to Embodiment 3 of the present invention;

[0037] Figure 10 This is a schematic diagram of the arrangement of blast holes, water bags, and detonation delay for trench blasting according to Embodiment 4 of the present invention;

[0038] Figure 11 This is a diagram showing the drilling and water bag layout for the test blast zone in Embodiment 4 of the present invention;

[0039] Figure 12 This is a diagram showing the formation of water mist and dust suppression in the explosion zone during a dust suppression test of Embodiment 4 of the present invention.

[0040] Figure 13 This is a diagram showing the lithology and borehole layout of the dustfall test explosion zone in Embodiment 5 of the present invention;

[0041] Figure 14 This is a diagram showing the formation of water mist and dust suppression in the explosion zone during a dust suppression test of Embodiment 5 of the present invention. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] The rapid development of the national economy has led to an increasing demand for mineral resources year by year, and the intensity of mineral resource mining has become increasingly greater. my country's metal mining is mainly open-pit mining. Compared with underground mining, open-pit mining has the advantages of large mining space, low mining cost, and high labor efficiency.

[0044] In recent years, people's environmental awareness has been increasing, and they have paid more and more attention to public hazards such as toxic fumes, dust and noise. Open-pit mining generates a lot of dust, and the atmospheric pollution caused by the diffusion of toxic fumes and visible dust has become a focus of attention.

[0045] Based on their sources, dust can be divided into natural dust and anthropogenic dust. Natural dust is mainly generated by geological and climatic factors, as well as natural factors such as rock weathering and earthquakes, on the surface of the mine. Anthropogenic dust is generated at various stages of mining operations. In actual mining, the impact of natural activities on the environment is much smaller than that of dust generated by mining operations. Therefore, the main source of dust in mines is anthropogenic dust caused by mining operations.

[0046] Example 1

[0047] See Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 This embodiment provides a method for dust suppression by generating a water mist curtain from open-pit mine blasting dust, including the following steps:

[0048] Step 1: Arrange the blast holes

[0049] Taking the blasting area located at the 1416m level of the south side of the main mining area of ​​Baiyun Iron Mine as an example, the bench height of the blasting area is 15m, the blasted rock mass is mica schist, and the blasting holes are drilled with a diameter of 310mm using a rotary drill. The blast holes are distributed in a triangular pattern with a row spacing of 8m×6m. Depending on the site conditions, 7 to 8 rows of blast holes are arranged in the blasting area. The blast holes are 1.5 to 2.0m deep, and most of the blast holes contain water with a depth of 3 to 4m.

[0050] The blast holes are filled with mixed emulsion explosives at the site, with a single hole charge of 800-950 kg. The charge amount for the front row of blast holes is adjusted according to the actual minimum resistance line. The upper interval control of the blast hole is implemented using a water-air-water separator, and the blast hole blocking length is 6.0-6.5 m. The blast holes are blocked by pushing the rock powder from the drill holes with a tamping machine.

[0051] The design of the electronic detonator-precise, hole-by-hole detonation boreholes is as follows: the middle borehole in the first row is designated as the detonation zero point; the delay between boreholes within the same row is 45ms, and the delay between boreholes in different rows is 65ms. The borehole layout and precise detonation delay design of the blast zone are as follows: Figure 3 As shown in the figure (the numbers in the figure are the detonation time, ms; the straight line segment is the exploding water bag);

[0052] Step 2: Setting up and adjusting the water bag

[0053] The blast zone was detonated in a V-shape with the middle borehole of the first row as the zero point. At the blasting site, one side of the blast zone was designated for generating and suppressing explosive water mist, while the other side was left untreated. A comparative test was conducted on the dust suppression and non-dust suppression effects under the same rock type and blasting conditions. Following the principles of "forward blocking, blast zone coverage, synchronous generation, and on-site adsorption," two rows of explosive water bags were placed in front of the blast zone on the dust suppression side, and four explosive water bags were placed inside the blast zone. The water bags were arranged as follows: Figure 3 As shown;

[0054] The detonation delay of the water bags in the blast zone is taken as the detonation delay time of the last row of blast holes corresponding to the water bag. The detonation time of the two rows of water bags in front of the blast zone is determined to be 1300ms according to the initial velocity of the broken rock block, the projection angle and the distance between the water bag and the bottom line of the slope.

[0055] Step 3: Water mist generation and dust suppression

[0056] Underneath the water bags, detonating cords ignited by electronic detonators are laid. The detonating cord cores are made of RDX or Taian, with a charge of 12.0–14.0 g / m. The electronic detonators are connected in parallel to the overall detonation network of the blast area, forming a complete parallel detonation network. After the blast area is detonated, the detonating cords are detonated by electronic detonators, forming an explosive water mist field that blocks the slope and covers the upper part of the blast area, thereby achieving dust suppression in the blast area.

[0057] Step 4: Effect Observation

[0058] The dust suppression effect in the explosion zone was observed on-site by DIC at a test frequency of 60 FPS. The test results showed that the water mist field generated by the explosion water bag in front of the explosion zone was formed synchronously with the mushroom cloud of blasting smoke and dust. The high-speed water mist field formed was equivalent to a high-speed water mist curtain that effectively intercepted the forward expansion of the blasting mushroom cloud in real time.

[0059] After the water bags in the blast zone were activated, they formed an upper water mist field covering the dust suppression side, providing real-time, on-site coverage of the rapidly rising mushroom cloud of blasting dust. The water mist field blocking the explosion from the front and the upper covering water mist field together formed the overall spatial water mist field on the dust suppression side of the coverage design. A total of 29.1 tons of water was instantaneously activated, forming a thick water mist field that simultaneously and in-situ adsorbed and neutralized the blasting dust. The blasting mushroom cloud exhibited a distinct light gray dust effect, such as... Figure 4 As shown ( Figure 4 The image on the left shows dust suppression with water mist covering the slope in front and water mist covering the top, while the image on the right shows dust suppression with water mist covering the slope in front and water mist covering the top. This contrasts sharply with the dense black mushroom cloud on the side where no dust suppression explosion water bags were placed, demonstrating the significant dust suppression effect at the pollution source.

[0060] The dust concentration in the comparison areas on both sides of the test explosion zone was measured on-site using an FCS-30 dust sampler (as shown in Table 1 below). The dust concentration test results for the dust-falling zone and the non-dust-falling zone are as follows:

[0061] ① The dust concentration at a distance of 50m from the blast zone was 165.832mg / m³. 3 It decreased to 113.333 mg / m³ 3 Dust concentration decreased by 46%;

[0062] ② The dust concentration at a distance of 100m from the blast zone was 96.673mg / m³. 3 It decreased to 70.423 mg / m³ 3 It decreased by 37%;

[0063] like Figure 5 As shown, on-site observation after the blast revealed that the surface of the blast pile on one side of the dust suppression zone was moistened by the water mist sprayed from the explosion, creating favorable conditions for dust control during the next electric shovel operation.

[0064] Table 1. Test Record of On-site Dust Suppression Test in Explosion Water Mist Field

[0065]

[0066] Example 2

[0067] See Figure 1 , Figure 6 , Figure 7 This embodiment provides a method for generating a water mist curtain to suppress dust from open-pit mine blasting, including the following steps:

[0068] Step 1: Arrange the blast holes

[0069] Taking the blasting area located at the 1416m level of the south side of the main mining area of ​​Baiyun Iron Mine as an example, the rock mass in the blasting area is mica schist with an f coefficient of 10-11. The blasting area is about 120m long and the average bench height is 15.5m. Vertical deep holes with a diameter of 310mm are drilled using a roller cone drill. The design borehole depth is 1.5m. The boreholes on the bench plane are arranged in a triangular pattern with a hole spacing of 9m×5m. Based on the bench plane conditions, 5-6 rows of boreholes are arranged before and after the blasting area, with a total of 65 holes.

[0070] After drilling was completed, the water depth inside the borehole was measured to be between 2 and 3 meters. The design was to plug the borehole to a depth of 6.5 to 7.0 meters. For individual boreholes with a water depth exceeding 8.0 meters, the upper part was separated by a water hole and an air spacer, and then the borehole was plugged with drilled rock powder.

[0071] The borehole loading was carried out on-site using a mixed emulsion explosive loading vehicle. The actual charge amount in the borehole was controlled by an onboard metering device and a borehole loading height measurement method. The designed total charge amount for the blasting zone was 53 tons of emulsion explosive. The dust suppression test blasting zone was as follows: Figure 6 As shown;

[0072] Step 2: Setting up and adjusting the water bag

[0073] The blasting zone was detonated in a V-shape with the middle blast hole of the first row as the zero point. At the blasting site, one side of the blasting zone was set up for generating explosive water mist and dust suppression, while the other side was not treated for dust suppression. A comparative test of the dust suppression and non-dust suppression effects was conducted under the same rock type and blasting conditions. In accordance with the principle of "forward blocking, blasting zone coverage, synchronous generation and on-site adsorption", two explosive water bags were set up in front of the blasting zone on the dust suppression side, and four explosive water bags were set up inside the blasting zone.

[0074] The detonation delay of the water bags in the blast zone is taken as the detonation delay time of the last row of blast holes corresponding to the water bag. The detonation time of the two rows of water bags in front of the blast zone is determined to be 1300ms according to the initial velocity of the broken rock block, the projection angle and the distance between the water bag and the bottom line of the slope.

[0075] Step 3: Water mist generation and dust suppression

[0076] Underneath the water bags, detonating cords ignited by electronic detonators are laid. The detonating cord cores are made of RDX or Taian, with a charge of 12.0–14.0 g / m. The electronic detonators are connected in parallel to the overall detonation network of the blast area, forming a complete parallel detonation network. After the blast area is detonated, the detonating cords are detonated by electronic detonators, forming an explosive water mist field that blocks the slope and covers the upper part of the blast area, thereby achieving dust suppression in the blast area.

[0077] Step 4: Effect Observation

[0078] The real-time dustfall dynamics of the formation of the explosion water mist field and the mushroom dust cloud from the explosion are as follows: Figure 7 As shown ( Figure 7 The left image shows the water bag activation at the front of the slope, and the right image shows the water mist generated by the upper covering and the water mist interception at the front of the slope, which also helps with dust suppression. The images show that the water mist field generated by the water bag activation at the top of the steps is generated synchronously with the mushroom cloud from the explosion, covering the mushroom dust cloud in real time. The water mist field generated by the water bag activation at the front of the slope acts like a water mist curtain, which effectively intercepts the lateral expansion of the mushroom smoke cloud from the explosion. The high-intensity explosion water mist field adsorbs dust in real time and neutralizes toxic fumes simultaneously. The black mushroom cloud is clearly transformed into a light gray color, showing a significant dust suppression effect.

[0079] The dust concentration in the comparison areas on both sides of the test explosion zone was measured on-site using an FCS-30 dust sampler (as shown in Table 2 below). The dust concentration test results for the dust-falling zone and the non-dust-falling zone are as follows:

[0080] ① The dust concentration at a distance of 50m from the blast zone was 135.231mg / m³. 3 It decreased to 93.537 mg / m³ 3 Dust concentration decreased by 44.6%;

[0081] ② The dust concentration at a distance of 100m from the blast zone was 76.341mg / m³. 3 It decreased to 54.234 mg / m³ 3 This represents a decrease of 40.8%.

[0082] ③ The design capacity for explosive water spraying is 28.6t, and the average water consumption per unit of dust suppression by explosive is 0.236kg / t.

[0083] Table 2. Test Record of Dust Suppression in Explosion Water Mist Field - Part 2

[0084]

[0085] Example 3

[0086] See Figure 1 , Figure 8 , Figure 9 This embodiment provides a method for dust suppression by generating a water mist curtain from open-pit mine blasting dust, including the following steps:

[0087] Step 1: Arrange the blast holes

[0088] The blasting zone is approximately 80m long with an average bench height of 15.0m. The blasting zone consists of ore and locally mixed rock. Vertical deep holes with a diameter of 310mm are drilled using a rotary drill. The design depth of the blast holes is 1.5m. The blast holes are arranged in a triangular pattern on the bench plane with a row spacing of 8m × 6m. Based on the bench plane conditions, 8 to 9 rows of blast holes are arranged before and after the blasting zone, for a total of 68 holes.

[0089] After drilling, borehole measurements showed no water inside. The borehole was designed to be plugged to a depth of 6.5–7.0 meters. The explosive charge was carried out on-site using a mixed ammonium nitrate explosive (ANFO) loading vehicle. The actual charge amount was controlled using an onboard metering device and a borehole charge height measurement method. The designed total charge for the blasting zone was 53 tons of emulsion explosive. The borehole was plugged with drilled rock powder. A dust suppression test was conducted in the test blasting zone. Figure 8 As shown;

[0090] Step 2: Setting up and adjusting the water bag

[0091] The blasting zone was detonated in a V-shape with the middle blast hole of the first row as the zero point. At the blasting site, one side of the blasting zone was set up for generating explosive water mist and dust suppression, while the other side was not treated for dust suppression. A comparative test of the dust suppression and non-dust suppression effects was conducted under the same rock type and blasting conditions. In accordance with the principle of "forward blocking, blasting zone coverage, synchronous generation and on-site adsorption", two explosive water bags were set up in front of the blasting zone on the dust suppression side, and four explosive water bags were set up inside the blasting zone.

[0092] The detonation delay of the water bags in the blast zone is taken as the detonation delay time of the last row of blast holes corresponding to the water bag. The detonation time of the two rows of water bags in front of the blast zone is determined to be 1300ms according to the initial velocity of the broken rock block, the projection angle and the distance between the water bag and the bottom line of the slope.

[0093] Step 3: Water mist generation and dust suppression

[0094] Underneath the water bags, detonating cords ignited by electronic detonators are laid. The detonating cord cores are made of RDX or Taian, with a charge of 12.0–14.0 g / m. The electronic detonators are connected in parallel to the overall detonation network of the blast area, forming a complete parallel detonation network. After the blast area is detonated, the detonating cords are detonated by electronic detonators, forming an explosive water mist field that blocks the slope and covers the upper part of the blast area, thereby achieving dust suppression in the blast area.

[0095] Step 4: Effect Observation

[0096] The dust suppression effect in the blast area was observed on-site using DIC (Digital Interference Capacity) technology. The real-time dynamic process of dust suppression, including the formation of the explosion water mist field and the mushroom dust cloud from the blast, was recorded as follows: Figure 9 As shown ( Figure 9 The left image shows the rising water mist curtain in front of the slope, and the right image shows the water mist in front of the slope plus the water mist generation and dust settling in the upper part of the slope. The image shows that the water mist field generated by the water bag on the upper part of the step is generated synchronously with the mushroom cloud of the explosion, covering the mushroom dust cloud in real time.

[0097] The water mist field generated by the water bags at the front of the slope acted as a water mist curtain, effectively intercepting the lateral expansion of the mushroom cloud of blasting smoke. The high-intensity explosion water mist field adsorbed dust in real time and neutralized toxic fumes simultaneously, resulting in a noticeable dust suppression effect as the black mushroom cloud was transformed into a light gray color. Figure 9 The prominent column of smoke and dust in the middle is the rear row of punch holes;

[0098] The dust concentration in the comparison areas on both sides of the test explosion zone was measured on-site using an FCS-30 dust sampler (as shown in Table 3 below). The dust concentration test results for the dust-falling zone and the non-dust-falling zone are as follows:

[0099] ① The dust concentration at a distance of 50m from the blast zone was 163.532mg / m³. 3 It decreased to 115.351 mg / m³ 3 Dust concentration decreased by 41.8%;

[0100] ② The dust concentration at a distance of 100m from the blast zone decreased from 96.411mg / m³. 3 It decreased to 68.420 mg / m³ 3 This represents a decrease of 40.9%.

[0101] ③ Explosion spraying 12.5t, the average water consumption for dust suppression based on the designed blasting volume is 0.147kg / t;

[0102] like Figure 5 As shown, on-site observation after the blast revealed that the surface of the blast pile on one side of the dust suppression zone was moistened by the water mist sprayed from the explosion, creating favorable conditions for dust control during the next electric shovel operation.

[0103] Table 3. Test Record Table for Dust Suppression in Explosion Water Mist Field

[0104]

[0105] Example 4

[0106] See Figure 1 , Figure 10 , Figure 11 , Figure 12 This embodiment provides a method for dust suppression by generating a water mist curtain from open-pit mine blasting dust, including the following steps:

[0107] Step 1: Arrange the blast holes

[0108] Taking the blasting area located at the 1374m horizontal trench in the main mining area of ​​Baiyun Mine as an example, the blasting area is about 50m long, the trench bench is 15.0m high, and the lithology of the blasting area is iron ore magnetite quartzite. Vertical deep holes with a diameter of 310mm are drilled using a roller cone drill. The design borehole depth is 2.0m. The boreholes on the bench plane are arranged in a rectangular pattern with a hole row spacing of 6m×6m. Based on the truck transportation conditions, 8 rows of boreholes are arranged on the bench plane, with a total of 66 holes.

[0109] After drilling, measurements showed that all boreholes contained water, with a depth of 8-10m. Some boreholes were completely filled with water. The design included a 7.0m borehole plugging depth, using water-air spacers for upper-level separation. The boreholes were plugged with drilled rock debris. Emulsion explosives were loaded onto the boreholes using a mixed-load vehicle. The actual charge amount was controlled by an onboard meter and a borehole charge height measurement method. The total charge for the blast zone was designed to be 65t of emulsion explosives. The borehole layout and detonation design are as follows: Figure 10 As shown, the actual situation of the dust suppression test explosion zone is as follows: Figure 11 As shown;

[0110] Step 2: Setting up and adjusting the water bag

[0111] Dust suppression in the trench blasting area is implemented using water bags deployed according to the design principle of "surrounding interception, synchronous generation, and on-site adsorption." Based on the characteristics of the water mist field generation, the lateral coverage area of ​​a single water bag water mist field is determined to be approximately 100m². 2 The water bags are positioned 8 meters from the outer edge of the blast zone. The water mist generated by the water bags on both sides of the blast zone can basically cover the blast zone. No water bags are placed at the trench entrance. The other three sides are arranged as follows: Figure 11 As shown, the design requires approximately 14.0 tons of water for dust suppression;

[0112] The detonation of the water-filled explosive bags was appropriately delayed after the blast hole detonation (using an MS11 detonator to activate the water-filled bags). At this time, the dust mushroom cloud in the blast zone was in its early stages of formation, with a high dust concentration but not yet spreading outwards on a large scale. Simultaneously, the water mist field was generated and rapidly expanded to cover the mushroom cloud in the blast zone, achieving the environmental protection goal of synchronous expansion of the dust cloud and water mist field, and on-site adsorption of dust and neutralization of blast fumes. The detonation delay between the blast hole and the water-filled explosive bags was as follows: Figure 10 As shown;

[0113] Step 3: Water mist generation and dust suppression

[0114] Underneath the water bags, detonating cords ignited by electronic detonators are laid. The detonating cord cores are made of RDX or Taian, with a charge of 12.0–14.0 g / m. The electronic detonators are connected in parallel to the overall detonation network of the blast area, forming a complete parallel detonation network. After the blast area is detonated, the detonating cords are detonated by electronic detonators, forming an explosive water mist field that blocks the slope and covers the upper part of the blast area, thereby achieving dust suppression in the blast area.

[0115] Step 4: Effect Observation

[0116] The dust suppression effect in the blast zone was observed on-site using DIC (Digital Interference Capacity) at a test frequency of 60 FPS. The real-time dynamic process of dust suppression, including the formation of the explosion water mist field and the mushroom dust cloud, was recorded as follows: Figure 12 As shown in the figure (part a in the figure is the upper interception water mist covering the smoke and dust, and part b is the interception water mist covering the smoke and dust to reduce dust), the figure shows that the water mist field generated by the water bag at the top of the steps is generated synchronously with the mushroom cloud of the explosion, and the mushroom dust cloud is intercepted in real time; as the high-speed water mist field formed by the interception water bag is rapidly generated, the smoke and dust cloud blown by the wind is intercepted and covered by the three water mist curtain walls in time.

[0117] The dust concentration in the comparison areas on both sides of the test explosion zone was measured on-site using an FCS-30 dust sampler (as shown in Table 4 below). The dust concentration test results for the dust-falling zone and the non-dust-falling zone are as follows:

[0118] ① The dust concentration at a distance of 50m from the blast zone decreased from 134.231mg / m³. 3 It decreased to 96.242 mg / m³ 3 Dust concentration decreased by 40%;

[0119] ② The dust concentration at a distance of 100m from the blast zone decreased from 93.212mg / m³. 3 It decreased to 69.171 mg / m³ 3 It decreased by 39%.

[0120] ③ Explosion spraying 11.2t, the average water consumption for dust suppression during blasting is designed to be 0.178kg / t.

[0121] Table 4. Test Record Table for Dust Suppression in Explosion Water Mist Field

[0122]

[0123] Example 5

[0124] See Figure 1 , Figure 13 , Figure 14 This embodiment provides a method for dust suppression by generating a water mist curtain from open-pit mine blasting dust, including the following steps:

[0125] Step 1: Arrange the blast holes

[0126] Taking the blasting area located at the 1430m level N side of the main mining area of ​​Baiyun Mine as an example, the blasting area is about 80m long and the designed bench height is 15.0m. The ore area of ​​the blasting area is a magnetite quartzite ore area. Vertical deep holes with a diameter of 310mm are drilled using a roller cone drill. The designed blast hole depth is 1.0m. The blast holes on the bench plane are arranged in a triangular pattern with a hole spacing of 6m×7m. Based on the bench width and the surrounding road conditions, 4 to 6 rows of blast holes are arranged on the bench plane, with a total of 122 holes. According to the blast hole measurement, some blast holes are dry and some blast holes have a small amount of water, with a water depth of 1 to 2m.

[0127] The borehole was designed to be plugged to a depth of 7.0m, with upper spacing achieved using water-hole air spacers. The borehole was plugged with drill rock debris. The explosive charge was carried out on-site using a mixed emulsion explosive loading vehicle. The actual charge amount was controlled by an onboard metering device and a borehole charge height measurement method. The total charge in the designed blast zone was 99t of emulsion explosive. A dust suppression test was conducted in the test blast zone as follows: Figure 13 As shown;

[0128] Step 2: Setting up and adjusting the water bag

[0129] The blasting zone was detonated in a V-shape with the middle blast hole of the first row as the zero point. At the blasting site, one side of the blasting zone was set up for generating explosive water mist and dust suppression, while the other side was not treated for dust suppression. A comparative test of the dust suppression and non-dust suppression effects was conducted under the same rock type and blasting conditions. In accordance with the principle of "forward blocking, blasting zone coverage, synchronous generation and on-site adsorption", two explosive water bags were set up in front of the blasting zone on the dust suppression side, and four explosive water bags were set up inside the blasting zone.

[0130] The detonation delay of the water bags in the blast zone is taken as the detonation delay time of the last row of blast holes corresponding to the water bag. The detonation time of the two rows of water bags in front of the blast zone is determined to be 1300ms according to the initial velocity of the broken rock block, the projection angle and the distance between the water bag and the bottom line of the slope.

[0131] Step 3: Water mist generation and dust suppression

[0132] Underneath the water bags, detonating cords ignited by electronic detonators are laid. The detonating cord cores are made of RDX or Taian, with a charge of 12.0–14.0 g / m. The electronic detonators are connected in parallel to the overall detonation network of the blast area, forming a complete parallel detonation network. After the blast area is detonated, the detonating cords are detonated by electronic detonators, forming an explosive water mist field that blocks the slope and covers the upper part of the blast area, thereby achieving dust suppression in the blast area.

[0133] Step 4: Effect Observation

[0134] The dust suppression effect in the blast zone was observed on-site using DIC (Digital Interference Capacity) at a test frequency of 60 FPS. The real-time dynamic process of dust suppression, including the formation of the explosion water mist field and the mushroom dust cloud, was recorded as follows: Figure 14 As shown ( Figure 14 Part a in the diagram is the water bag that triggers the explosion at the top, part b is the water mist generated at the top of the steps, part c is the water mist that intercepts and expands the smoke and dust at the rear, and part d is the water mist covering at the top and the smoke and dust being intercepted and reduced at the rear. The diagram shows that the water mist field formed by the water bag at the top of the steps is generated synchronously with the mushroom cloud from the explosion, covering and adsorbing the mushroom cloud in real time. At the same time as the mushroom cloud forms, the high-speed explosion water mist adsorbs the blast smoke and covers the dust, turning the smoke and dust cloud into a light gray color, which contrasts sharply with the black mushroom cloud in the non-dust-reducing area.

[0135] The dust concentration in the comparison areas on both sides of the test explosion zone was measured on-site using an FCS-30 dust sampler (as shown in Table 5 below). The dust concentration test results for the dust-falling zone and the non-dust-falling zone are as follows:

[0136] ① The dust concentration at a distance of 50m from the blast zone was 127.412mg / m³. 3 It decreased to 89.541 mg / m³ 3 Dust concentration decreased by 42%;

[0137] ② The dust concentration at a distance of 100m from the blast zone was 89.432mg / m³. 3 It decreased to 67.971 mg / m³ 3 This represents a decrease of 31.6%.

[0138] ③ Explosion spraying 16.5t, the average water consumption for dust suppression during blasting is designed to be 0.278kg / t.

[0139] like Figure 5 As shown, on-site observation after the blast revealed that the surface of the blast pile on one side of the dust suppression zone was moistened by the water mist sprayed from the explosion, creating favorable conditions for dust control during the next electric shovel operation.

[0140] Table 5. Test Record Table for Dust Suppression in Explosion Water Mist Field

[0141]

[0142] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for generating a water mist curtain to suppress dust from open-pit mine blasting, characterized in that, Includes the following steps: Step 1: Based on the actual drilling conditions of the blasting, design the location and quantity of water bags, the range and direction of the water mist spray. When designing the location and quantity of water bags, for the open-pit mining bench blasting area, design 1 to 2 water bags on the lower part of the bench in front of the bench slope, with a spacing of 6 to 8 meters between the water bags. In the bench blasting area, deploy explosive water bags at a spacing of 14 to 16 meters along the direction of the blasting area. For the trenching and blasting area, no water bags are placed at the trench opening, but one water bag is placed on each of the other three sides, at a distance of 8m from the outer edge of the trenching and blasting area. Step 2: Level the site for water-filled bags and lay the detonating cord, which will be detonated by an electronic detonator, along the length of the site in the middle. Step 3: Lay water bags at the designed location, install the water mist spray control device, and adjust the opening range and direction of the control device. Lay the water bags along the detonating cord so that the detonating cord is directly below the water bags. The water mist spray control device is placed on both sides of the water bags, one on each side. The spray range and angle of the water mist are controlled by adjusting the spacing and angle. The water mist spray control device consists of two wooden boards and an angle adjustment hinge to achieve angle adjustment. The water bags are hollow tube bags made of polyethylene plastic film with a diameter of 300-350mm, and are filled with water. Step 4: After detonation in the blast zone, the detonating cord is detonated using an electronic detonator, forming an explosive water mist field that blocks the slope and covers the upper part of the blast zone, thereby reducing dust in the blast zone. The activation time of the two rows of water bags in front of the stepped blast zone is determined according to the initial velocity of the broken rock blocks, the projection angle, and the distance between the water bags and the slope bottom line. The delayed activation time t of the explosive water bags after detonation in the blast hole is determined by the following formula: ； in, L The horizontal distance from the detonation point of the front row of the exploding water bag; Step 5: Conduct on-site observation of the dust suppression effect in the blast area using DIC, and use an FCS-30 dust sampler to measure the dust concentration in the blast area on-site to evaluate the dust suppression effect of the explosion water mist on the blast area after detonation.

2. The method for generating a water mist curtain to suppress dust from open-pit mine blasting as described in claim 1, characterized in that: In step one, when designing the range and direction of the water mist spray, the water mist spray range is concentrated at the lower step of the step slope and the outer edge of the trench blasting area, and the direction is vertically upward or inclined towards the blasting area to play an interception role.

3. The method for generating a water mist curtain to suppress dust from open-pit mine blasting as described in claim 1, characterized in that: In step one, when designing the spray range and direction of the water mist curtain, the spray range of the water mist curtain is expanded and the direction is dispersed in all directions at the middle position of the two rows of blast holes, so as to achieve a covering effect.

4. The method for generating a water mist curtain to suppress dust from open-pit mine blasting as described in claim 1, characterized in that: In step two, the width of the site is equal to the diameter of the water bag, and after leveling, there are no large pieces or sharp objects.

5. The method for generating a water mist curtain to suppress dust from open-pit mine blasting as described in claim 1, characterized in that: In step two, the detonating cord is placed along its length in the middle of the leveled site.

6. The method for generating a water mist curtain to suppress dust from open-pit mine blasting as described in claim 1, characterized in that: In step four, the explosive water bags laid out along the direction of the blast zone within the stepped blast zone trigger the electronic detonators to detonate synchronously with the last row of blast holes corresponding to the water bags. The detonating cord core is made of RDX or TAIAN, with a charge of 12.0–14.0 g / m. The electronic detonators are connected in parallel to the overall blast zone detonation network, forming a complete parallel detonation network.

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