Explosive-dry ice collaborative blasting method

Abstract

The invention relates to the technical field of rock mass blasting, in particular to an explosive-dry ice collaborative blasting method which comprises the following steps that S1, hole net parameters are determined according to a rock mass structure and the field environment of a pre-blasting area, the positions of blast holes are set, and the blast holes comprise slotting holes, auxiliary holes, caving holes and peripheral holes; s2, according to the formula (a), the explosive loading amount Q needed by the blasting single hole is calculated; s3, dry ice, an initiator and a detonator are put into the blast hole, and the blast hole is sealed; s4, connecting a detonator detonating network and detonating; wherein in the step S3, the initiator is an explosive. According to the method, dry ice is adopted as a phase change rock breaking material, and is quickly sublimated under the action of energy released by initiator-explosive explosion to generate a large amount of carbon dioxide gas, so that the explosive energy utilization efficiency is increased, the explosive amount is reduced, the blasting effect is improved, the blasting vibration is reduced, the resource utilization of carbon dioxide is further enhanced, and the method is green and environment-friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of rock blasting, and specifically, to a method for synergistic blasting of explosive - dry ice. Background Art

[0002] With the modernization drive and development of our country, the blasting operation environment has become increasingly complex, and the requirements for blasting safety have also become higher and higher. In engineering practice, it is necessary to strictly control the impact of blasting harmful effects. For engineering blasting using industrial explosives such as emulsion explosives and ammonium - based explosives as the initiation energy source: Advantages: Widely used, with mature technology and rich experience, capable of generating powerful shock waves and fragmentation forces; Disadvantages: Causing harmful effects such as strong seismic waves, air shock waves, noise, and blasting fly - rocks, having problems such as high blasting costs and excessive fragmentation of the surrounding rock mass.

[0003] To improve blasting safety and reduce blasting vibration, the current blasting industry is gradually exploring and implementing technologies such as static expanders for rock breaking and phase - change rock breaking with liquid carbon dioxide. However, due to certain safety hazards and high costs of these technologies, they do not meet the conditions for large - scale application.

[0004] Since there is generally a problem of large vibration in current blasting operations, this is because traditional continuous charging results in a high amount of explosive in a single blast hole, and the instantaneous explosion generates strong dynamic and air shock waves acting on the surrounding rock walls, causing vibration. Currently, mainly the method of interval charging is adopted to reduce the amount of explosive in a single hole to reduce blasting vibration. However, interval charging also has problems such as poor rock fragmentation and loosening, and poor blasting effect. This has put the current traditional blasting industry in a dilemma regarding the impact of blasting harmful effects on the surrounding residential building environment. With the increasingly strict national safety management of mine exploitation, the restricted factors for blasting operations are also increasing day by day, mainly concentrated on the impact of the explosion harmful effects generated by blasting operations on the surrounding residential buildings. The seven departments including the Ministry of Natural Resources jointly issued the "Notice on Further Strengthening the Construction of Green Mines", which pointed out: Accelerate the promotion of the application of green and low - carbon advanced and applicable technologies. However, the harmful effects such as vibration and dust pollution caused by current mine blasting operations have not been well solved.

[0005] Therefore, researching and developing an economical and safe blasting method is the trend of development research. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the present invention provides a method for synergistic blasting of explosive - dry ice. This method uses dry ice as a phase - change rock - breaking material, which rapidly sublimes under the action of the energy released by the explosion of the initiator - explosive, generating a large amount of carbon dioxide gas, increasing the energy utilization efficiency of the explosive, reducing the amount of explosive while improving the blasting effect and reducing blasting vibration, further strengthening the resource utilization of carbon dioxide, and being green and environmentally friendly.

[0007] To achieve the above object, the present invention provides a method for collaborative blasting of explosive and dry ice, and the method includes the following steps:

[0008] S1. Determine the hole pattern parameters according to the rock mass structure and the on-site environment of the pre-blasting area, and set the positions of blast holes, which include cut holes, auxiliary holes, broken holes and perimeter holes;

[0009] S2. Calculate the charge amount Q required for a single blast hole according to formula (a):

[0010] Q = q×S×L×n (a);

[0011] wherein, Q is the charge amount of a single hole, q is the unit explosive consumption (kg / m 3 , S is the cross-sectional area of the blast hole, L is the depth of the blast hole, and n is the hole utilization rate, that is, the ratio of the effective charge of the blast hole to the hole depth;

[0012] S3. Put dry ice, initiator and detonator into the blast hole and seal the blast hole;

[0013] S4. Connect the detonators into a network and detonate the detonators;

[0014] wherein, in step S3, the initiator is an explosive.

[0015] Preferably, in step S1, the hole pattern parameters include hole depth, hole diameter, minimum burden, hole spacing, row spacing, overbreak depth and stemming length.

[0016] Preferably, the explosive is selected from one or two or more of emulsion explosive, water gel explosive, ammonium fuel oil explosive, aluminized explosive, TNT and RDX.

[0017] Preferably, in step S3, the mass ratio of the dry ice to the initiator is 1:1 to 3.

[0018] Preferably, in step S3, the detonator is placed in the initiator, and the initiator is in contact with one side or multiple sides of the dry ice.

[0019] Preferably, the contact method is to place the dry ice on the side and bottom of the initiator.

[0020] Preferably, the contact method is to place the dry ice on the top of the initiator.

[0021] Preferably, the contact method is to place the dry ice between two groups of initiators, and the two groups of initiators are respectively located at the top and bottom of the dry ice.

[0022] Preferably, the masses of the two groups of initiators are the same.

[0023] Preferably, the dry ice is granular.

[0024] Preferably, in step S3, the particle size of the dry ice is 1-10 mm.

[0025] Preferably, in step S3, the method of sealing the blast holes includes manually sealing the holes with a hole-sealing material and / or using a mechanical hole-sealing device for hole sealing.

[0026] Preferably, in step S3, the detonator is selected from one or more of digital electronic detonators, fire detonators, electric detonators, and non-electric detonators.

[0027] According to the above technical solution, the present invention uses dry ice as a phase change rock-breaking material, establishes a method for explosive-dry ice synergistic blasting, optimizes the dry ice blasting parameters, such as the effective charge structure and the dry ice incorporation amount, reduces the peak pressure on the blast hole wall and the crushed zone of the surrounding rock mass, effectively improves the energy utilization rate, reduces the blasting vibration without affecting the blasting effect, and at the same time reduces the powder ore rate by more than 10%.

[0028] The explosive-dry ice synergistic blasting method of the present invention is a first-of-its-kind technology at home and abroad. Compared with the liquid CO2 blasting technology, it has the advantages of high safety, convenient operation, good rock-breaking effect, and obvious economic benefits. At the same time, the popularization and application of the explosive-dry ice synergistic blasting method of the present invention can effectively reduce the production cost, and the physical and chemical properties of dry ice are stable and it does not belong to dangerous chemicals. At the same time, the low temperature has no influence on the performance and safety of explosives and detonators, and the loading process is the same as that of explosives, with simple and easy operation and safe and reliable process.

[0029] Furthermore, the explosive-dry ice synergistic blasting method of the present invention is mainly applied to the blasting work in mine mining, which can effectively reduce the harmful effects such as explosion shock waves, vibrations, noises, and dust generated by traditional engineering blasting, and at the same time realize the resource utilization of carbon dioxide, which is of great significance for promoting the green, low-carbon, and high-quality development of mines.

[0030] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation part. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific implementation manners, they are used to explain the present invention, but do not constitute a limitation to the present invention. In the drawings:

[0032] Figure 1 is a schematic diagram of a blasting funnel;

[0033] Figure 2 is a field experiment of a blasting funnel;

[0034] Figure 3 is the experimental result of a blasting funnel;

[0035] Figure 4It is a schematic diagram of experimental temperature acquisition;

[0036] Figure 5 It is the experimental result of the influence of dry ice on explosives;

[0037] Figure 6 It is the change of the microscopic morphology of the explosive emulsion matrix;

[0038] Figure 7 It is the change of detonation velocity of emulsion explosive at different temperatures

[0039] Figure 8 In the figure, a is the schematic diagram of the loading structure of Comparative Example 1, b is the schematic diagram of the loading structure of Example 1, c is the schematic diagram of the loading structure of Example 2, and d is the schematic diagram of the loading structure of Example 3;

[0040] Figure 9 It is the rock-breaking effect of different loading structures;

[0041] Figure 10 It is the maximum resultant velocity change curve under different dry ice ratios;

[0042] Figure 11 It is the blasting effect of different dry ice ratios. Detailed implementation manners

[0043] The following further describes in detail the specific implementation manners of the present invention with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only for explaining and understanding the present invention, and are not used to limit the present invention.

[0044] The endpoints and any values disclosed in this article are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this article.

[0045] The present invention provides a method for cooperative blasting of explosives and dry ice, and the method includes the following steps:

[0046] S1. Determine the hole pattern parameters according to the rock mass structure and the on-site environment of the pre-blasting area, and set the positions of blast holes, which include cut holes, auxiliary holes, breakage holes and perimeter holes;

[0047] S2. Calculate the charge amount Q required for a single blasting hole according to formula (a):

[0048] Q = q × S × L × n (a);

[0049] Wherein, Q is the charge amount of a single hole, and q is the unit explosive consumption kg / m 3, S is the cross-sectional area of the blast hole, L is the depth of the blast hole, and n is the utilization rate of the blast hole, that is, the ratio of the effective charge in the blast hole to the hole depth;

[0050] S3. Put dry ice, initiator and detonator into the blast hole and seal the blast hole;

[0051] S4. Connect the detonators into a network and detonate the detonators;

[0052] Among them, in step S3, the initiator is an explosive.

[0053] In a preferred embodiment of the present invention, in order to achieve an ideal blasting effect and reduce the powder ore rate, in step S1, the hole pattern parameters include hole depth, hole diameter, minimum burden, hole spacing, row spacing, overbreak depth and stemming length.

[0054] In a preferred embodiment of the present invention, in order to ensure that the dry ice can be quickly and effectively initiated, the explosive is selected from one or two or more of emulsion explosive, water gel explosive, ammonium nitrate fuel oil explosive, aluminum-containing explosive, TNT and RDX.

[0055] In a preferred embodiment of the present invention, in order to ensure that the dry ice can be quickly and effectively initiated, in step S3, the mass ratio of the dry ice to the initiator is 1:1 to 3.

[0056] In a preferred embodiment of the present invention, in order to ensure that the dry ice can be quickly and effectively initiated, in step S3, the detonator is placed in the initiator, and the initiator is in contact with one or more sides of the dry ice. The contact area is large, and the phase change sublimation expansion speed of the dry ice is fast.

[0057] In a preferred embodiment of the present invention, side wrapping type is used for charging. The contact method is to place the dry ice on the side and bottom of the initiator. The advantage is that the contact area between the dry ice and the explosive is large, and the disadvantage is that the operation is complex and the charging cost is high.

[0058] In a preferred embodiment of the present invention, in order to ensure that the dry ice can be quickly and effectively initiated, the contact method is to place the dry ice on the top of the initiator. The structure of top charging is simple, but the contact area is limited and the blasting effect is poor.

[0059] In a preferred embodiment of the present invention, in order to ensure that the dry ice can be quickly and effectively initiated, the contact method is to place the dry ice between two groups of initiators. The two groups of initiators are located at the top and bottom of the dry ice respectively. The sandwich type charging is simple in operation and can effectively increase the contact area, which is the most economical and practical charging structure.

[0060] In a preferred embodiment of the present invention, in order to ensure that the dry ice can be quickly and effectively initiated, the two groups of initiators have the same mass.

[0061] In a preferred embodiment of the present invention, in order to ensure good blasting effect, in step S3, the dry ice is granular.

[0062] In a preferred embodiment of the present invention, in order to ensure good blasting effect, in step S3, the particle size of the dry ice is 1-10 mm.

[0063] In a preferred embodiment of the present invention, in order to prevent energy leakage and thus achieve good blasting effect, in step S3, the method of sealing the blast hole includes manually sealing the hole with a hole-sealing material and / or using a mechanical hole-sealing device for hole sealing.

[0064] In a preferred embodiment of the present invention, in step S3, the detonator is selected from one or more of digital electronic detonators, fire detonators, electric detonators, and non-electric detonators.

[0065] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto. In the following examples, the drugs and medicaments are all conventional commercially available products.

[0066] Example 1

[0067] (1) Determine the hole pattern parameters (hole depth, hole diameter, minimum burden, hole spacing, row spacing, overbreak depth, and stemming length) according to the rock mass structure and the on-site environment of the pre-blasting area, and set the positions of the blast holes. The blast holes include cut holes, auxiliary holes, breakage holes, and perimeter holes;

[0068] (2) Calculate the charge amount Q required for a single blast hole according to formula (a): Q = q × S × L × n (a);

[0069] Wherein, Q is the charge amount of a single hole, q is the unit explosive consumption in kg / m 3 , S is the cross-sectional area of the blast hole, L is the depth of the blast hole, and n is the hole utilization rate, that is, the ratio of the effective charge of the blast hole to the hole depth;

[0070] (3) Put 36 kg of dry ice, 4 kg of emulsion explosive, and an electronic detonator into the blast hole in a side-wrapping structure as shown in Figure 8 b, and seal the blast hole.

[0071] Example 2

[0072] Implement in the same manner as in Example 1, except that "put 36 kg of dry ice, 4 kg of emulsion explosive, and an electronic detonator into the blast hole in a side-wrapping structure as shown in Figure 8 b" in step (3) of Example 1 is replaced with "put 20 kg of dry ice, 20 kg of emulsion explosive, and an electronic detonator into the blast hole in a top-charging structure as shown in Figure 8 c", and the other steps remain unchanged.

[0073] Example 3

[0074] Implemented in the same manner as in Example 1, except that in step (3) of Example 1, "Put 36 kg of dry ice, 4 kg of emulsion explosive and electronic detonator into the blast hole in the side wrapping structure as shown in Figure 8 b" is replaced with "Put 20 kg of dry ice, 20 kg of emulsion explosive and electronic detonator into the blast hole in the sandwich charging structure as shown in Figure 8 d", and other steps remain unchanged.

[0075] Comparative Example 1

[0076] Implemented in the same manner as in Example 1, except that no dry ice is added and 40 kg of emulsion explosive is added, and other steps remain unchanged.

[0077] Comparative Example 2

[0078] Implemented in the same manner as in Example 1, except that "the initiator is emulsion explosive" in Example 1 is replaced with "the initiator is thermite", and other steps remain unchanged.

[0079] Initiation result: Thermite and magnesium strip have good thermal conductivity, resulting in difficulty in igniting the magnesium strip, and a heat preservation layer is required to wrap the thermite. After being wrapped with the heat preservation layer, although the thermite is successfully ignited, the thermite burns rapidly, and the generated energy is difficult to be quickly transferred to the dry ice, and a large amount of heat is dissipated into the air, and the heat exchange efficiency between the thermite and the dry ice is low.

[0080] Comparative Example 3

[0081] Implemented in the same manner as in Example 1, except that "the initiator is emulsion explosive" in Example 1 is replaced with "the initiator is self-heating agent, and the self-heating agent is made of a mixture of lime, calcium carbonate and aluminum powder", and other steps remain unchanged.

[0082] Initiation result: The sublimation speed of the self-heating agent dry ice is much faster than that of the thermite, but there are pores in the mine rock, and the generated gas is easy to escape from the pores, so it is difficult for the self-heating agent to achieve the rock-breaking effect.

[0083] Test Example 1

[0084] In order to explore the magnitude of the work done by dry ice for rock breaking and the required usage amount of dry ice equivalent to explosives under the same work done, a blasting funnel experiment was carried out. The schematic diagram of the blasting funnel is as shown in Figure 1 shown, and the experimental results are as shown in Table 1 and Figures 2-3 shown.

[0085] Table 1

[0086]

[0087]

[0088] From the data in Table 1 and Figures 2-3 the results, it can be seen that the rock-breaking work ability of 30 g of dry ice is approximately equal to that of 10 g of explosive.

[0089] Test Example 2

[0090] The explosive used at the blasting site has a specified temperature range of use. In order to explore the temperature change of the explosive at each position with time and its influence on the explosive matrix when the simulated dry ice is in contact with the explosive in the blast hole, an experiment on the influence of the contact range between dry ice and explosive was conducted. The schematic diagram of the experimental temperature acquisition is as Figure 4 shown, and the experimental results are as Figure 5 shown.

[0091] From Figure 5 it can be seen that after the dry ice contacts the explosive, thermocouples are respectively placed at 1 cm, 3 cm, 5 cm, 7 cm, and 9 cm away from the dry ice to obtain the temperature change curve of the explosive. After 1.5 h, the temperature of the explosive basically remains stable, fluctuating around -74 °C, -44 °C, -10 °C, 2 °C, 10 °C, and 15 °C respectively. Although water gel explosives are generally used above 0 °C, temperatures lower than this will cause a decrease in blasting power, poor sensitivity, and poor detonation transmission, but from the above results, it can be seen that there will be no influence beyond 5 cm from the contact surface between dry ice and explosive, and the influence on the overall blasting effect is extremely small and can be ignored.

[0092] Test Example 3

[0093] In order to observe the situation of dry ice affecting the explosive emulsion matrix from a microscopic perspective, the microscopic morphology of the emulsion matrix was observed under a microscope after the dry ice contacted the explosive. The results are as Figure 6 shown.

[0094] At Figure 6 are the explosive morphologies at 0 cm, 1 cm, 3 cm, 5 cm, 7 cm, and 9 cm away from the dry ice respectively. It can be seen that the closer to the dry ice, the lower the matrix temperature and the more serious the ammonium nitrate crystallization. However, the range of dry ice affecting the crystallization of the emulsion matrix is limited. It can be seen that the explosive at 5 cm away from the dry ice is hardly affected, and 9 cm basically reaches the limit range of the influence of dry ice.

[0095] Test Example 4

[0096] Due to the action of dry ice, the temperature of the explosive will be affected. The temperature change will have an impact on the detonation velocity of the explosive. In order to explore the detonation velocity experiment by placing the emulsion explosive in a constant temperature environment of 25 °C, 15 °C, 5 °C, -5 °C, and -15 °C for 3 hours respectively. The results are as Figure 7 shown.

[0097] From Figure 7It can be seen that as the temperature of the explosive decreases, the detonation velocity of the explosive decreases somewhat, but it can be detonated smoothly within the tested temperature range.

[0098] Test Example 5

[0099] The charging method without dry ice in Comparative Example 1 and the three different charging structures in Examples 1 - 3 were used for on - site single - hole blasting experiments at the same site. The experimental results are as Figure 9 shown in a - d.

[0100] Among them, Figure 9 a shows the blasting result of only filling the emulsion explosive in Comparative Example 1, and it can be seen that there is a rock - breaking effect. Figure 9 b - d are the blasting effects of the three different charging structures in Examples 1 - 3 respectively. It can be seen that the side - wrapping charging structure in Example 1 has a more obvious rock - breaking effect compared with the top - type charging structure in Example 2 and the sandwich - type charging structure in Example 3.

[0101] Test Example 6

[0102] In order to explore the magnitude of blasting vibration under different dry - ice - amount blasting experiments, vibration tests were carried out on the blasting site. The test scheme and results are shown in Table 2 and Figures 10-11 as shown.

[0103] Table 2

[0104]

[0105] From the data in Table 2 and Figure 10 the content, it can be known that when keeping the total mass of dry ice + explosive unchanged, the explosion vibration velocity (maximum resultant velocity) shows a gradually decreasing trend with the increase of the dry - ice amount, indicating that adding dry ice can effectively reduce blasting vibration. The blasting vibration velocity of the pure - explosive blast hole (192 kg) is 2.867 cm / s, and the blasting vibration velocity of the dry - ice blast hole (84 kg dry ice + 132 kg explosive) is 1.999 cm / s, which can reduce the vibration by 30.3% compared with the pure - explosive blast hole.

[0106] Figure 11 a - c are the blasting effects of Groups 1 - 3 respectively. It can be seen that the overall blasting effects of Groups 1 - 3 are good. Considering the comprehensive situation of blasting effect, large - block rate, throwing distance, subsequent loading and cost for blasting with a drilling diameter of 140 mm, the charging structure of 132 kg explosive + 84 kg dry ice, that is, the mass ratio of dry ice is 38% is a better charging scheme; while Figure 11 d - f are the blasting effects of Groups 4 - 6 respectively. It can be seen that the blasted block size and large - block rate at the experimental site of Groups 4 - 6 meet the requirements, but the post - blasting vibration is obvious, and the rocks in the second row are obviously not thrown out, and the blasting effect is not ideal.

[0107] Combining the above data and descriptions, the method of explosive-dry ice synergistic blasting of the present invention has the following advantages:

[0108] 1. Reduce blasting hazards: effectively reduce harmful effects such as blasting vibration, shock wave, and dust, and reduce the impact on surrounding structures and the environment of the mine;

[0109] 2. Reduce carbon emissions: Using 1 ton of dry ice reduces carbon emissions by about 1.74 tons compared to emulsion explosives;

[0110] 3. Application in blasting restricted areas: It can be used as a blasting technical means in areas with protected structures;

[0111] 4. Promote the recycling of CO2: Promote the resource utilization of carbon dioxide at the tail of the cement kiln and empower the green development of the mining industry.

[0112] The preferred embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0113] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0114] Furthermore, any combination can be made between various different embodiments of the present invention as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A method for explosive-dry ice collaborative blasting, characterized in that, The method comprises the following steps: S1. Determine the hole pattern parameters according to the rock mass structure and the on-site environment of the pre-blasting area, and set the positions of blast holes, which include cut holes, auxiliary holes, caving holes and perimeter holes; S2. Calculate the charge amount Q required for a single blast hole according to formula (a): Q = q × S × L × n (a); Among them, Q is the charge amount per single hole, q is the unit explosive consumption in kg / m 3 , S is the cross-sectional area of the blast hole, L is the depth of the blast hole, and n is the blast hole utilization rate, which is the ratio of the effective charge in the blast hole to the hole depth; S3. Put dry ice, initiator and detonator into the blast hole and seal the blast hole; S4. Connect the detonator initiation network and initiate; Wherein, in step S3, the initiator is explosive.

2. The method according to claim 1, wherein In step S1, the hole pattern parameters include hole depth, hole diameter, minimum burden, hole spacing, row spacing, stemming length and overbreak depth.

3. The method according to claim 1 or 2, characterized in that, The explosive is selected from one or two or more of emulsion explosive, water gel explosive, ammonium nitrate fuel oil explosive, aluminized explosive, TNT and RDX.

4. The method according to any one of claims 1 to 3, characterized in that In step S3, the mass ratio of the dry ice to the initiator is 1:1 to 3.

5. The method according to any one of claims 1-4, characterized in that In step S3, the detonator is placed in the initiator, and the initiator is in contact with one or more sides of the dry ice; Preferably, the contact mode is to place the dry ice on the side and bottom of the initiator; and / or The contact mode is to place the dry ice on the top of the initiator; and / or The contact mode is to place the dry ice between two groups of initiators, and the two groups of initiators are respectively located at the top and bottom of the dry ice; Preferably, the two groups of initiators have the same mass.

6. The method according to any one of claims 1-5, characterized in that In step S3, the dry ice is granular; Preferably, the particle size of the dry ice is 1 to 10 mm.

7. The method according to any one of claims 1-6, characterized in that, In step S3, the method of sealing the blast hole includes manually sealing the hole with a hole-sealing material and / or using a mechanical hole-sealing device to seal the hole.

8. The method according to any one of claims 1-7, characterized in that, In step S3, the detonator is selected from one or two or more of digital electronic detonators, fire detonators, electric detonators and non-electric detonators.

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