Method for reducing dust through water mist curtain generated by blasting dust in strip mine

Abstract

The invention discloses a water mist curtain dust falling method for blasting dust in strip mine blasting, which relates to the technical field of mine blasting and comprises the following steps: designing the position of a water mist curtain, arranging detonators and detonating fuses, arranging and adjusting water bags, generating water mist and falling dust, and observing the effect. According to the generation and expansion characteristics of blasting smoke and dust cloud, the water bag is arranged on the upper portion of the step and in front of the designed detonation zero point direction, and under the condition that the detonation network safety criterion of a detonation area is guaranteed, the setting size of the explosion water bag, the water mist gathering and scattering direction and the precise detonation excitation time are designed; the water bag is excited in real time in the process of forming blasting fume and dust cloud, so that an explosion water mist field covering mushroom dust cloud in a full blasting area and a throwing range is formed, and the mushroom dust cloud is intercepted and wholly coated and blasted; synchronous real-time interception, on-site adsorption, blasting fume dilution and neutralization and dust capture treatment of the atomized water field on blasting toxic blasting fume and dust particles are implemented, additional construction of blast holes is not needed, the action range is wide, and the dust falling effect is excellent.

Description

Technical Field

[0001] The invention relates to the technical field of mine blasting, in particular to a dust reduction method using a water mist curtain generated by open-pit mine blasting. Background Art

[0002] Open-pit mining has a vast scope and spoil dump, and a large amount of dust is generated in the spoil dump, mining platform, transportation road and electric shovel loading process. At present, this type of dust can be basically controlled by greening and consolidating the spoil dump, and sprinkling water on the transportation road surface, mining platform and loading process. However, for the main source of dust in open-pit mining - blasting dust, due to its instantaneous nature, high concentration and rapid and strong diffusion, traditional water sprinkling cannot be implemented simultaneously to reduce dust, so it is still powerless to prevent and control the blasting mushroom dust cloud.

[0003] According to measurements of foreign open-pit mines, 90% of open-pit mine dust comes from blasting mushroom dust clouds. Preliminary statistics from domestic metallurgical mines also show that open-pit blasting dust accounts for more than 80% of total mining dust. Blasting dust has high dust concentration, extremely fast diffusion speed, and a large dust diffusion range. It is generated instantaneously during the blasting and rock breaking process, and is extremely difficult to control. In addition, many mines have now entered the deep-pit mining state, and the lower working space is limited. Objectively, it is required that the smoke from production blasting be eliminated as soon as possible. Based on the above actual situation, if the traditional blasting dust treatment experience model of non-arid, deep-pit large-scale open-pit mines in the existing technology is applied and allowed to be eliminated freely, it will inevitably cause all kinds of workers in the mine and the air intake systems of major production equipment to suffer from high concentrations of dust and gun smoke, and the high incidence of silicosis among workers and high failure rates of operating equipment are common.

[0004] In the traditional iron ore blasting dust reduction treatment method, water spraying and mine water cannon vehicles cannot be implemented close to the blasting area due to safety requirements. Ground watering and water bag sealing of blast holes have only local effects and the dust reduction effect is not obvious. Therefore, the present invention proposes a water mist curtain dust reduction method for open-pit mine blasting dust to solve the problems existing in the prior art. Summary of the Invention

[0005] In view of the above problems, the purpose of the present invention is to propose a water mist curtain dust reduction method for open-pit mine blasting dust explosion, which solves the problem that the traditional iron ore blasting dust reduction treatment method cannot be implemented close to the blasting area due to water spraying and mine water cannon trucks due to safety requirements, and the ground sprinkling and water bag sealing of blast holes have only local effects and the dust reduction effect is not obvious.

[0006] In order to achieve the purpose of the present invention, the present invention is implemented by the following technical solution: a method for reducing dust by using a water mist curtain generated by blasting dust in an open-pit mine, comprising the following steps:

[0007] Step 1: According to the actual perforation situation of blasting, design the layout and quantity of water bags, the range and direction of water mist curtain spraying;

[0008] Step 2: Level the site for water bag layout, and lay detonating cords detonated by electronic detonators along the length direction at the middle position of the site.

[0009] Step 3: Lay water bags at the designed positions, install the regulating device for the water mist curtain ejection, and adjust the opening range and direction of the regulating device.

[0010] Step 4: After detonation in the blasting area, detonate the detonating cord by electronic detonators to form an explosion water mist field for blocking in front of the slope and covering the upper part of the blasting area, so as to realize the dust suppression treatment for the dust in the blasting area.

[0011] Step 5: Conduct in-situ DIC observation on the dust suppression effect of the blasting area, and conduct in-situ measurement on the dust concentration in the blasting area with an FCS-30 dust sampler to evaluate the dust suppression effect of the explosion water mist after initiation in the blasting area.

[0012] Further improvement lies in: In the above Step 1, for the water bag layout position and quantity, for the open-pit mining bench blasting area, design 1 - 2 rows of water bags at the lower front part of the bench slope, with a spacing of 6 - 8 m between the water bags, and arrange explosion water bags along the blasting area trend direction at a spacing of 14 - 16 m in the bench blasting area.

[0013] Further improvement lies in: In the above Step 1, for the water bag layout position and quantity, for the trenching blasting area, do not lay water bags at the end of the trench opening, and arrange 1 water bag on each of the other three sides, which are arranged 8 m away from the outer edge of the trenching blasting area.

[0014] Further improvement lies in: In the above Step 1, for the spraying range and direction of the water mist curtain, for the lower front part of the bench slope and the outer edge position of the trenching blasting area, the spraying range of the water mist curtain should be concentrated, and the direction is vertically upward or inclined towards the blasting area to play an interception role.

[0015] Further improvement lies in: In the above Step 1, for the spraying range and direction of the water mist curtain, for the middle position between two rows of blast holes, the spraying range of the water mist curtain should be wide, and the direction diverges in all directions to play a covering role.

[0016] Further improvement lies in: In the above Step 2, the site width is the diameter of the water bag, and there are no large blocks and sharp objects after leveling.

[0017] Further improvement lies in: In the above Step 2, the detonating cord is arranged along the length direction at the middle position of the leveled site.

[0018] Further improvement lies in: In the above Step 3, the water bags are laid along the detonating cord, so that the detonating cord is located directly below the water bags.

[0019] Further improvement lies in: In the above Step 3, the regulating device for the water mist curtain ejection is installed on both sides of the water bags, 1 on each side, and the spraying range and angle of the water mist curtain are controlled by adjusting the spacing and angle.

[0020] A further improvement lies in that: in the third step, the water mist curtain spraying and regulating device is composed of two wooden boards and angle adjusting hinges to achieve angle adjustment.

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

[0022] A further improvement lies in that: in the fourth step, the excitation times of the two rows of water bags in front of the bench blasting area are determined according to the initial velocity, projection angle of the broken rock blocks and the distance between the water bag and the slope bottom line. The delay excitation time t of the explosive water bag after the blast hole is detonated 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 of the explosive water bag from the front row initiation point, in m.

[0025] A further improvement lies in that: in the fourth step, for the explosive water bags arranged along the blast area trend direction in the bench blasting area, the excitation electronic detonators are detonated synchronously with the initiation time of the last row of blast holes corresponding to the water bags.

[0026] A further improvement lies in that: in the fourth step, the core of the detonating cord is cyclonite or penthrite, with a charge of 12.0 - 14.0 g / m. The electronic detonators are connected in parallel to the overall initiation network of the blast area to form a complete parallel initiation network.

[0027] The beneficial effects of the present invention are as follows: According to the generation and expansion characteristics of blasting fumes and dust clouds, a corresponding number and form of water bags are arranged in front of the upper part of the bench and in the direction of the designed initiation zero point. Under the condition of ensuring the safety criteria of the blast area initiation network, based on the generation characteristics of blasting fumes and dust clouds, the fixed-size and precise initiation excitation time of the explosive water bags are designed. The water bags are excited in real time during the formation of the blasting fumes and dust clouds to form an explosion water mist field covering the entire blasting area and the throwing range, in the shape of a mushroom dust cloud, which integrally wraps the blasting mushroom dust cloud, and the atomized water field is used to synchronously and real-time adsorb, dilute and neutralize the toxic blasting fumes and capture the dust particles on the spot. The scope of action is wider and the dust reduction effect is excellent, worthy of wide promotion and application. Description of the Drawings

[0028] Figure 1 is a schematic flow chart of the method for reducing dust by explosion-generated water mist curtain in open-pit mine blasting of the present invention;

[0029] Figure 2 is a schematic diagram of the structure and layout of the water mist curtain spraying and regulating device of the present invention;

[0030] Figure 3 It is a schematic diagram of the precise hole-by-hole initiation, explosion water mist generation and dust reduction layout design in the blasting area of the first embodiment of the present invention;

[0031] Figure 4 It is a live picture of the dust reduction effect of the explosion water mist curtain in the first embodiment of the present invention;

[0032] Figure 5 It is a picture of the blasted heap of the explosion water mist curtain dust reduction in the first embodiment of the present invention;

[0033] Figure 6 It is a schematic diagram of the layout of the dust reduction test blasting area in the second embodiment of the present invention;

[0034] Figure 7 It is a live picture of the explosion water mist generation and dust reduction in the blasting area of the second embodiment of the present invention;

[0035] Figure 8 It is a schematic diagram of the ore-rock distribution and drilling positions in the test blasting area of the third embodiment of the present invention;

[0036] Figure 9 It is a live picture of the explosion water mist generation and dust reduction in the blasting area of the third embodiment of the present invention;

[0037] Figure 10 It is a schematic diagram of the blast holes, water bags layout and initiation delay of the trench blasting in the fourth embodiment of the present invention;

[0038] Figure 11 It is a layout diagram of the drill holes and explosion water bags in the test blasting area of the fourth embodiment of the present invention;

[0039] Figure 12 It is a live picture of the explosion water mist generation and dust reduction in the test blasting area of the fourth embodiment of the present invention;

[0040] Figure 13 It is a lithology and hole position layout diagram of the dust reduction test blasting area in the fifth embodiment of the present invention;

[0041] Figure 14 It is a live picture of the explosion water mist generation and dust reduction in the dust reduction test blasting area of the fifth embodiment of the present invention. Detailed implementation manners

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0043] With the rapid development of the national economy, the demand for mineral resources has been increasing year by year, and the intensity of mineral resource exploitation has been growing. In China, the exploitation of metal mines is mainly open-pit mining. Compared with underground mining, open-pit mines have the characteristics of large mining space, low mining cost, and high labor efficiency.

[0044] In recent years, with the increasing awareness of environmental protection among people, the attention to public hazards such as toxic blasting fumes, dust, and noise has been growing. A large amount of dust is generated during the open-pit mining process. Among them, the atmospheric environmental pollution problems caused by the diffusion of toxic blasting fumes and visible dust have become the focus of attention.

[0045] According to the sources of dust generation, dust can be classified into natural dust generation and artificial dust generation. Natural dust generation is mainly due to the influence of geology, climate, rock weathering, earthquakes and other natural factors on the mine surface. Artificial dust generation is the dust generated in each link of mine production operations. In the actual mining process, the impact intensity of natural activities on the environment is much smaller than the smoke and dust caused by mine operation activities. Therefore, the main source of mine dust is artificial dust generation 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 reducing dust generated by blasting in an open-pit mine by means of a blasting-generated water mist curtain, including the following steps:

[0048] Step 1: Arrange blast holes

[0049] Taking the blasting area at the 1416m level on the south slope of the main mining area of Baiyun Iron Mine as an example, the bench height of the blasting area is 15m, the rock mass to be blasted is mica schist, and a rotary drill is used to drill blast holes with a diameter of 310mm. The blast holes are arranged in a triangular pattern, with a hole row spacing of 8m×6m. According to the on-site conditions, 7 to 8 rows of blast holes are arranged in the blasting area. The overburden depth of the blast holes is 1.5 to 2.0m, and most of the blast holes are filled with water, with the water depth ranging from 3 to 4m.

[0050] The blast holes are filled with site-mixed emulsion explosives. The charge per hole is 800 - 950kg. The charge of the front-row blast holes is adjusted according to the actual minimum burden. An air-water interval device for water holes is used to control the upper interval and the stemming length of the blast holes is 6.0 - 6.5m, and a stemming machine is used to push and block the drill cuttings in the borehole to block the blast holes.

[0051] Design electronic detonators to accurately initiate the charged blast holes one by one. The middle blast hole in the first row is set as the initiation zero point. The delay between blast holes in the same row is 45ms, and the delay between rows of holes is 65ms. The layout of the blast holes in the blasting area and the design of the accurate initiation delay of the blast holes are as shown in Figure 3 shown (the numbers in the figure are the initiation times, ms; the straight line segments are explosive water bags);

[0052] Step 2: Arrangement and adjustment of water bags

[0053] For the V-shaped initiation with the middle blast hole in the first row of the blasting area as the zero point, one side of the blasting area at the blasting site is arranged for the generation of explosion water mist and dust reduction, and the other side is not treated for dust reduction. A comparative test of dust reduction and non-dust reduction effects is carried out under the same lithology and blasting conditions. According to the principle of "front blocking, blasting area coverage, synchronous generation and in-situ adsorption", two rows of explosion water bags are arranged in front of the blasting area on the dust reduction side, and four explosion water bags are arranged in the blasting area. The arrangement of the water bags is as Figure 3 shown;

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

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

[0056] Detonating cords detonated by electronic detonators are laid under all the arranged water bags. The explosive core of the detonating cord is cyclonite or pentaerythritol tetranitrate, and the charge amount is 12.0 - 14.0 g / m. The electronic detonators are connected in parallel to the overall initiation network of the blasting area to form a complete parallel initiation network. After the blasting area is detonated, the detonating cords are detonated by the electronic detonators to form an explosion water mist field for blocking in front of the slope and covering the upper part of the blasting area, so as to realize the dust reduction treatment of the dust in the blasting area;

[0057] Step 4: Effect observation

[0058] DIC on-site observation was carried out on the dust reduction effect of the blasting area, and the test frequency was 60 FPS. The test results showed that the water mist field formed by the excitation of the explosion water bags in front of the blasting area was formed synchronously with the mushroom cloud of the front-rushing blasting smoke and dust. The formed high-speed water mist field was equivalent to a high-speed water mist curtain, which effectively intercepted the front-rushing expansion of the blasting mushroom smoke and dust cloud in real time;

[0059] After the explosion water bags in the blasting area were excited, an upper water mist field covering the dust suppression side was formed, which covered the rapidly rising blasting mushroom smoke and dust cloud in real time and in-situ. The water mist field blocking in front and the upper covering water mist field jointly formed an overall spatial water mist field covering the designed dust suppression side. A total of 29.1 t of water was instantaneously excited to form a thick and wide water mist field to synchronously adsorb and neutralize the blasting smoke and dust in real time and in-situ. The blasting mushroom smoke and dust showed an obvious light gray smoke and dust effect, as Figure 4 shown ( Figure 4 in the left figure in [ ] is the dust reduction by the water mist in front of the slope + the upper water mist covering, and the right figure is the dust reduction by the water mist in front of the slope + the upper water mist covering), which forms a sharp contrast with the thick black mushroom cloud on the side without the arranged dust reduction explosion water bags, and the direct dust reduction effect at the pollution source is obvious;

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

[0061] ① At a distance of 50 m from the blasting area, the dust concentration decreased from 165.832 mg / m 3 to 113.333 mg / m 3 , and the dust concentration decreased by 46%;

[0062] ② At a distance of 100 m from the blasting area, the dust concentration decreased from 96.673 mg / m 3 to 70.423 mg / m 3 , a decrease of 37%;

[0063] As Figure 5 shown, after blasting, it can be seen from on-site observation that the surface of the muck pile on the dust fall area side was wetted by the explosion water mist after spraying, creating favorable conditions for dust control in the next-step electric shovel operation.

[0064] Table 1 Test record form of the dust fall field test of the explosion water mist field

[0065]

[0066] Example 2

[0067] Refer to Figure 1 、 Figure 6 、 Figure 7 , this example provides an open-pit mine blasting dust explosion-generated water mist curtain dust fall method, including the following steps:

[0068] Step 1. Layout of blast holes

[0069] Taking the blasting area on the south slope of the 1416 m level in 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 length of the blasting area is about 120 m, the average bench height is 15.5 m, vertical deep holes with a diameter of 310 mm are drilled using a rotary drill, the designed overburden depth of the blast holes is 1.5 m, the blast holes are arranged in a triangular pattern on the bench plane, the hole row spacing is 9 m × 5 m, and 5 - 6 rows of blast holes are arranged before and after the blasting area according to the bench plane conditions, with a total of 65 blast holes;

[0070] After perforation, it is known from blast hole measurement that the water depth in the blast holes ranges from 2 to 3 m. The designed blast hole stemming is 6.5 - 7.0 m. For individual blast holes with a water depth exceeding 8.0 m, upper interval is implemented using an air spacer for the water holes, and then the blast holes are stemmed with drill cuttings;

[0071] Emulsion explosive mixing trucks are used for on-site charging of the blast holes. The actual charge amount in the blast holes is controlled by on-vehicle measuring devices and the blast hole charging height measurement method. The designed total charge amount for the blasting area is 53 t of emulsion explosive. The test blasting area for the dust fall test is asFigure 6 as shown;

[0072] Step 2: Arrange and adjust the water bags

[0073] For the V-shaped initiation with the middle blast hole in the first row of the blasting area as the zero point, one side of the blasting site is arranged for the generation of explosion water mist and dust reduction, while the other side is not treated for dust reduction. A dust reduction and non-dust reduction effect comparison test is carried out under the same lithology and blasting conditions. According to the principle of "front block, blasting area coverage, synchronous generation and in-situ adsorption", two explosion water bags are arranged in front of the blasting area on the dust reduction side, and four explosion water bags are arranged in the blasting area;

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

[0075] Step 3: Generate water mist and reduce dust

[0076] Detonating cords detonated by electronic detonators are laid under all the arranged water bags. The core of the detonating cord is cyclonite or penthrite, and the charge amount is 12.0 - 14.0 g / m. The electronic detonators are connected in parallel to the overall initiation network of the blasting area to form a complete parallel initiation network. After the blasting area is detonated, the detonating cords are detonated by the electronic detonators to form an explosion water mist field for blocking in front of the slope and covering the upper part of the blasting area, realizing the dust reduction treatment of the blasting area dust;

[0077] Step 4: Effect observation

[0078] The real-time dust reduction dynamic process of the explosion water mist field formation and the blasting mushroom dust cloud is as Figure 7 shown ( Figure 7 in the left figure in it, the water bags in front of the slope are excited, and in the right figure, the upper covering water mist + the water mist generated by the front slope interception for dust reduction), the figure shows that the water mist field formed by the excitation of the water bags on the upper part of the bench is generated synchronously with the blasting mushroom cloud and covers the mushroom dust cloud in real time; the water mist field formed by the excitation of the water bags in front of the slope intercepts the lateral expansion of the blasting mushroom dust cloud like a water mist curtain in time. The high-strength explosion water mist field adsorbs dust in real time and neutralizes toxic blasting fumes synchronously, and the visible black mushroom cloud is transformed into a light gray obvious dust suppression effect;

[0079] The dust concentration in the comparison areas on both sides of the test blasting area was measured on site with an FCS-30 dust sampler (as shown in Table 2 below). The test results of the dust concentration on the dust reduction area side and the non-dust reduction area are as follows:

[0080] ① At a distance of 50 m from the blasting area, the dust concentration decreased from 135.231 mg / m 3 to 93.537 mg / m 3 , and the dust concentration decreased by 44.6%;

[0081] ② The dust concentration at a distance of 100 m from the blasting area decreased from 76.341 mg / m 3 to 54.234 mg / m 3 , a decrease of 40.8%;

[0082] ③ It is designed to sprinkle 28.6 t of water for blasting, and the average water consumption for dust reduction per unit blasting is 0.236 kg / t.

[0083] Table 2 Test Record Table of the Second Dust Reduction Field Test of the Explosion Water Mist Field

[0084]

[0085] Example 3

[0086] See Figure 1 , Figure 8 , Figure 9 , this example provides a method for reducing dust by generating an explosion water mist curtain in open-pit mine blasting, including the following steps:

[0087] Step 1: Arrange blast holes

[0088] The length of the blasting area is about 80 m, the average bench height is 15.0 m, the blasting area is ore and local mixed rock, and a vertical deep hole with a diameter of 310 mm is drilled with a rotary drill. The designed overburden depth of the blast hole is 1.5 m. The blast holes are arranged in a triangular pattern on the bench plane, and the hole spacing is 8 m × 6 m. According to the bench plane conditions, 8 - 9 rows of blast holes are arranged before and after the blasting area, and the total number of blast holes is 68;

[0089] After the drilling is completed, it is known through blast hole measurement that there is no water in the blast hole. The designed blast hole stemming is 6.5 - 7.0 m. The blast hole charging is carried out on-site using an ammonium nitrate fuel oil mixed loading truck, and the actual blast hole charge amount is controlled by an on-vehicle meter and the blast hole charging height measurement method. The designed total charge amount for the blasting area is 53 t of emulsion explosive, and the blast hole is plugged with drill cuttings. The dust reduction test blasting area is as Figure 8 shown;

[0090] Step 2: Arrange and adjust the water bags

[0091] The blasting area is detonated in a V-shaped pattern with the middle blast hole in the first row as the zero point. On the blasting site, one side of the blasting area is arranged for the generation and dust reduction of the explosion water mist, and the other side is not treated for dust reduction. A comparative test of dust reduction and non-dust reduction effects is carried out under the same lithology and blasting conditions. According to the principle of "front blocking, blast area covering, synchronous generation, and in-situ adsorption", two rows of explosion water bags are arranged in front of the dust reduction side of the blasting area, and four rows of explosion water bags are arranged in the blasting area;

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

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

[0094] Detonating cords detonated by electronic detonators are laid under the arranged water bags. The explosive core of the detonating cord is cyclonite or penthrite, and the charge is 12.0 - 14.0 g / m. The electronic detonators are connected in parallel to the overall initiation network in the blasting area to form a complete parallel initiation network. After the blasting area is detonated, the detonating cord is detonated by the electronic detonator to form an explosive water mist field for blocking in front of the slope and covering the upper part of the blasting area, so as to realize the dust suppression treatment of the blasting area;

[0095] Step 4: Effect observation

[0096] DIC on-site observation was carried out on the dust suppression effect in the blasting area. The real-time dust suppression dynamic process of the formation of the explosive water mist field and the blasting mushroom dust cloud is as Figure 9 shown ( Figure 9 in the left figure in it, the water mist curtain in front of the slope rises, and in the right figure, the water mist in front of the slope + the upper water mist is generated and the dust is suppressed). The figure shows that the water mist field formed by the excitation of the water bags on the upper part of the bench is generated synchronously with the blasting mushroom cloud and covers the mushroom dust cloud in real time;

[0097] The water mist field formed by the excitation of the water bags in the front of the slope intercepts the lateral expansion of the blasting mushroom dust cloud like a water mist curtain wall in time. The high-strength explosive water mist field adsorbs dust in real time and neutralizes toxic blasting fumes synchronously, and the visible black mushroom cloud is transformed into a light gray obvious dust suppression effect ( Figure 9 the prominent dust column in it is the back row of punched blast holes);

[0098] The dust concentration in the comparison areas on both sides of the test blasting area was measured on-site with an FCS-30 dust sampler (as shown in Table 3 below). The test results of the dust concentration on the dust suppression area side and the non-dust suppression area are as follows:

[0099] ① At a distance of 50 m from the blasting area, the dust concentration decreased from 163.532 mg / m 3 to 115.351 mg / m 3 , and the dust concentration decreased by 41.8%;

[0100] ② At a distance of 100 m from the blasting area, the dust concentration decreased from 96.411 mg / m 3 to 68.420 mg / m 3 , a decrease of 40.9%;

[0101] ③ 12.5 t of explosive sprinkler water was used, and the average water consumption for dust suppression per ton of designed blasting volume was 0.147 kg / t;

[0102] As Figure 5 shown, it can be seen from on-site observation after blasting that the surface of the muck pile on the dust suppression area side is wet after being sprayed with explosive water mist, creating favorable conditions for the dust control of the next-stage electric shovel operation.

[0103] Table 3 Record Sheet of the Third Test of the Dust Suppression Field Test of Explosion Water Mist

[0104]

[0105] Example 4

[0106] See Figure 1 、 Figure 10 、 Figure 11 、 Figure 12 This example provides a method for suppressing dust by generating a water mist curtain from the explosion dust of open-pit mines, including the following steps:

[0107] Step 1: Arrange blast holes

[0108] Taking the blasting area at the 1374m level trenching in the main mining area of Baiyun Mine as an example, the length of the blasting area is about 50m, the height of the trenching bench is 15.0m, the lithology of the blasting area is iron ore magnetite quartzite, vertical deep holes with a diameter of 310mm are drilled with a rotary drill, the designed overburden depth of the blast holes is 2.0m, the blast holes on the bench plane are arranged in a rectangle, the hole spacing is 6m×6m, and according to the conditions of truck transportation, 8 rows of blast holes are arranged on the bench plane, and the total number of blast holes is 66;

[0109] After perforation, it is known from the measurement of blast holes that all blast holes have water, the water depth in the holes is 8 - 10m, and some blast holes are full of water. The designed plugging length of the blast holes is 7.0m. The upper interval is implemented with a water hole air spacer, and the blast holes are plugged with cuttings powder from the drilling. The charging of the blast holes is carried out on-site with an emulsion explosive mixing truck, and the actual charge amount of the blast holes is controlled by an on-vehicle meter and the method of measuring the charging height of the blast holes. The designed total charge amount of the blasting area is 65t of emulsion explosive. The blast hole layout and initiation design are as Figure 10 shown, and the actual situation of the blasting area for the dust suppression test is as Figure 11 shown;

[0110] Step 2: Arrange and adjust water bags

[0111] For dust suppression in the trenching blasting area, explosion water bags are arranged according to the design principle of "intercepting on all sides, generating synchronously, and adsorbing locally". According to the generation characteristics of the explosion water mist field, it is determined that the lateral coverage area of the water mist field of a single water bag is about 100m 2 , which is arranged 8m away from the outer edge of the blasting area. The water mist fields generated by the water bags arranged on both sides of the blasting area can basically cover the blasting area. No water bags are arranged at the end of the trench opening, and the other three sides are arranged as Figure 11 shown, and the designed water consumption for dust suppression is about 14.0t;

[0112] The explosive water bags are triggered with an appropriate delay after the blast holes are detonated (initiated with MS11 detonators). At the initial stage of the formation of the dust mushroom cloud in the entire blast area and when the dust concentration is at a high level but has not yet spread out on a large scale, the explosion water mist field is excited and generated at this time, rapidly expanding to cover the blast area mushroom cloud, achieving the environmental protection goal of synchronous spatial expansion of the dust cloud and the water mist field, and adsorbing dust in place and neutralizing the blasting fumes. The initiation delay between the blast holes and the explosive water bags in the blast area is as Figure 10 shown;

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

[0114] Detonating cords detonated by electronic detonators are laid under all the arranged water bags. The explosive core of the detonating cord is cyclonite or pentaerythritol tetranitrate, and the charge is 12.0 - 14.0 g / m. The electronic detonators are connected in parallel to the overall initiation network in the blast area to form a complete parallel initiation network. After the blast area is detonated, the detonating cord is detonated by the electronic detonators to form an explosion water mist field that blocks in front of the slope and covers the upper part of the blast area, achieving the dust suppression treatment for the dust in the blast area;

[0115] Step 4. Effect observation

[0116] DIC on-site observation was carried out on the dust suppression effect in the blast area, and the test frequency was 60 FPS. The real-time dust suppression dynamic process of the explosion water mist field formation and the blasting mushroom dust cloud is as Figure 12 shown (part a in the figure is the upper intercepted water mist covering the smoke and dust, and part b is the dust suppression of the intercepted water mist covering the smoke and dust). The figure shows that the water mist field formed by the excitation of the upper water bags on the bench is generated synchronously with the blasting mushroom cloud, and the mushroom dust cloud is intercepted in real time; as the high-speed water mist field formed by the intercepted water bags is rapidly generated, the smoke and dust cloud blown by the wind is timely intercepted and covered by the three-sided water mist curtain walls;

[0117] The dust concentration in the comparison areas on both sides of the test blast area was measured on-site with an FCS-30 dust sampler (as shown in Table 4 below). The test results of the dust concentration on the dust suppression area side and the non-dust suppression area are as follows:

[0118] ① The dust concentration at 50 m from the blast area decreased from 134.231 mg / m 3 to 96.242 mg / m 3 , and the dust concentration decreased by 40%;

[0119] ② The dust concentration at 100 m from the blast area decreased from 93.212 mg / m 3 to 69.171 mg / m 3 , a decrease of 39%.

[0120] ③ 11.2 t of explosion sprinkler water was used, and the average water consumption for designed blasting dust suppression was 0.178 kg / t.

[0121] Table 4 Test record form for the on-site test of dust suppression by the explosion water mist field

[0122]

[0123] Example 5

[0124] See Figure 1 、 Figure 13 、 Figure 14 This embodiment provides a method for dust reduction by explosion-generated water mist curtain in open-pit mine blasting, including the following steps:

[0125] Step 1: Arrange blast holes

[0126] Taking the blasting area located in the N side of the 1430m level of the main mining area of Baiyun Ore Mine as an example, the length of the blasting area is about 80m, the designed bench height is 15.0m, and the lithology of the blasting area is an ore area of magnetite quartzite. Vertical deep holes with a diameter of 310mm are drilled with a rotary drill. The designed overburden depth of the blast holes is 1.0m. The blast holes are arranged in a triangular pattern on the bench plane, and the hole spacing is 6m×7m. According to the bench width and surrounding road conditions, 4 to 6 rows of blast holes are arranged on the bench plane, and the total number of blast holes is 122. Through blast hole measurement, it is known that some blast holes have no water and some have a small amount of water with a water depth of 1 to 2m;

[0127] The designed blast hole plugging length is 7.0m. The upper interval is implemented using a water hole air spacer, and the blast holes are plugged with drill cuttings powder. The blast hole charging is carried out on-site using an emulsion explosive mixing truck. The actual blast hole charge amount is controlled by an on-vehicle meter and the blast hole charging height measurement method. The designed total charge amount of the blasting area is 99t of emulsion explosive. The blasting area for the dust reduction test is as Figure 13 shown;

[0128] Step 2: Arrange and adjust water bags

[0129] The blasting area is detonated in a V-shaped pattern with the middle blast hole in the first row as the zero point. On the blasting site, one side of the blasting area is arranged for explosion water mist generation and dust reduction, and the other side is not treated for dust reduction. A dust reduction and non-dust reduction effect comparison test is carried out under the same lithology and blasting conditions. According to the principle of "front block, blasting area coverage, synchronous generation and in-situ adsorption", two rows of explosion water bags are arranged in front of the dust reduction side of the blasting area, and four rows of explosion water bags are arranged in the blasting area;

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

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

[0132] Detonating cords detonated by electronic detonators are laid under all the arranged water bags. The explosive core of the detonating cord is cyclonite or pentaerythritol tetranitrate, and the charge amount is 12.0 - 14.0 g / m. The electronic detonators are connected in parallel to the overall initiation network of the blasting area to form a complete parallel initiation network. After the blasting area is detonated, the detonating cords are detonated by the electronic detonators to form an explosion water mist field for blocking in front of the slope and covering the upper part of the blasting area, so as to realize the dust suppression treatment of the dust in the blasting area;

[0133] Step 4. Effect observation

[0134] DIC on-site observation was carried out on the dust suppression effect of the blasting area, and the test frequency was 60 FPS. The real-time dust suppression dynamic process of the formation of the explosion water mist field and the blasting mushroom dust cloud is as Figure 14 shown ( Figure 14 in part a of

[0135] is the excitation of the upper explosion water bags, part b is the generation of water mist above the bench, part c is the interception of the smoke and dust expansion by the rear water mist, and part d is the dust suppression by the upper water mist coverage + rear interception of the smoke and dust). The figure shows that the water mist field formed by the excitation of the upper water bags on the bench is generated synchronously with the blasting mushroom cloud, and it covers and adsorbs the mushroom dust cloud in real time. When the mushroom cloud is formed, the high-speed explosion water mist adsorbs the gun smoke and covers the dust, and the smoke and dust cloud turns into a light gray shape, forming a sharp contrast with the black mushroom cloud in the non-dust suppression area;

[0136] ① At a distance of 50 m from the blasting area, the dust concentration decreased from 127.412 mg / m 3 to 89.541 mg / m 3 , and the dust concentration decreased by 42%;

[0137] ② At a distance of 100 m from the blasting area, the dust concentration decreased from 89.432 mg / m 3 to 67.971 mg / m 3 , a decrease of 31.6%;

[0138] ③ 16.5 t of explosion sprinkler water was used, and the average water consumption for designed blasting dust suppression was 0.278 kg / t.

[0139] As Figure 5 shown, it can be seen from the on-site observation after blasting that the surface of the muck pile on the dust suppression area side is wet after being sprayed with the explosion water mist, creating favorable conditions for the dust control in the next step of the electric shovel operation.

[0140] Table 5 Test record form of the dust suppression on-site test of the explosion water mist field

[0141]

[0142] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for reducing dust by generating a water mist curtain during open-pit mine blasting, characterized in that, It includes the following steps: Step 1: According to the actual perforation situation of the blasting, design the layout position and quantity of the water bags, the spraying range and direction of the water mist curtain; Step 2: Level the site for laying the water bags, and lay detonating cord along the length direction at the middle position of the site, which is detonated by electronic detonators; Step 3: Lay the water bags at the designed positions, install the regulating device for spraying the water mist curtain, and adjust the opening range and direction of the regulating device; Step 4: After the blasting area is detonated, detonate the detonating cord through electronic detonators to form an explosive water mist field for blocking in front of the slope and covering the upper part of the blasting area, so as to realize the dust reduction treatment of the dust in the blasting area; Step 5: Conduct in-situ DIC observation on the dust reduction effect of the blasting area, and use an FCS-30 dust sampler to measure the dust concentration in the blasting area on-site to evaluate the dust reduction effect of the explosive water mist after the blasting area is detonated.

2. A method for reducing dust by generating water mist curtain during open-pit mine blasting according to claim 1, characterized in that: In the above Step 1, when designing the layout position and quantity of the water bags, for the bench blasting area in open-pit mining, 1 - 2 rows of water bags are designed at the lower front part of the bench slope, with a spacing of 6 - 8 m between the water bags, and explosive water bags are arranged at intervals of 14 - 16 m along the strike direction of the blasting area in the bench blasting area.

3. A method for reducing dust generated by blasting in open-pit mines using an explosion-generated water mist curtain, characterized in that: In the above Step 1, when designing the layout position and quantity of the water bags, for the trenching blasting area, no water bags are arranged at the end of the trench opening, and 1 water bag is arranged on each of the other three sides, which is arranged 8 m away from the outer edge of the trenching blasting area.

4. A method for reducing dust by explosion-generated water mist curtain in open-pit mine blasting according to claim 1, characterized in that: In the above Step 1, when designing the spraying range and direction of the water mist curtain, for the lower front part of the bench slope and the outer edge position of the trenching blasting area, make the spraying range of the water mist curtain concentrated, and the direction is vertically upward or inclined towards the blasting area to play an interception role.

5. A method for reducing dust by explosion-generated water mist curtain in open-pit mine blasting according to claim 1, characterized in that: In the above Step 1, when designing the spraying range and direction of the water mist curtain, for the middle position between two rows of blast holes, make the spraying range of the water mist curtain expand, and the direction diverges around to play a covering role.

6. The dust reduction method by using explosion-generated water mist curtain for open-pit mine blasting according to claim 1, characterized in that: In the above Step 2, the width of the site is the diameter of the water bag, and there are no large blocks and sharp objects after leveling.

7. A method for reducing dust by explosion-generated water mist curtain in open-pit mine blasting according to claim 1, characterized in that: In the above Step 2, the detonating cord is arranged along the length direction at the middle position of the leveled site.

8. A method for reducing dust by generating a water mist curtain from the explosion of blasting dust in an open-pit mine according to claim 1, characterized in that: In the above Step 3, the water bags are laid along the detonating cord, making the detonating cord located directly below the water bags. The regulating device for spraying the water mist curtain is installed on both sides of the water bags, one on each side. The spraying range and angle of the water mist curtain are controlled by adjusting the spacing and angle. The regulating device for spraying the water mist curtain is composed of two wooden boards and an angle-adjusting hinge to realize angle adjustment. The water bag is a hollow cylindrical bag made of polyethylene plastic film, with a diameter of 300 - 350 mm and filled with water inside.

9. A method for reducing dust by generating a water mist curtain from the explosion of blasting dust in an open-pit mine according to claim 1, characterized in that: In the above Step 4, the firing time of the two rows of water bags in front of the bench blasting area is determined according to the initial velocity, projection angle of the broken rock blocks and the distance between the water bag and the slope bottom line. The delay firing time t of the explosive water bag after the blast holes are detonated can be determined by the following formula: t = 0.89716 - 0.1055L + 0.00985L 2 -1.2(s), L ∈ (11, 31) Where, L is the horizontal distance between the explosive water bag and the front row of initiation points.

10. A method for reducing dust by explosion-generated water mist curtain in open-pit mine blasting according to claim 1, characterized in that: In the above Step 4, for the explosive water bags arranged along the strike direction of the blasting area in the bench blasting area, the electronic detonators are fired synchronously with the last row of blast holes corresponding to the water bags. The detonator core of the detonating cord is RDX or PETN, and the charge amount is 12.0 - 14.0 g / m. The electronic detonators are connected in parallel to the overall initiation network of the blasting area to form a complete parallel initiation network.

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