Method for blasting sedimentary and metamorphic surface iron ore close to side and boundaries

Abstract

The invention discloses a side-to-boundary blasting method for sedimentary metamorphic surface iron ore, and relates to the technical field of iron ore blasting construction, which comprises the following steps of: drilling: selecting a proper drilling position according to a rock mass exploration result; charging: uniformly distributing ammonium nitrate fuel oil explosives in the drill hole by adopting a segmented charging mode, and installing a primer detonator; blocking: after charging is completed, cement paste and gravel are mixed to form a blocking material to tightly block the main blasting hole; detonating: transmitting a detonating signal, detonating the detonator, and enabling the explosive to explode in the main blasting hole; according to the method, the charge density of the presplitting line is adjusted to 0.5 kg / m from 0.7 kg / m, the presplitting line is segmented into 10 m sections, the single-shot charge is controlled to be 60 kg or below, the use amount of explosives is reduced, the propagation range and strength of shock waves and stress waves generated during blasting can be reduced, direct impact and damage to the side slope can be reduced, and the mode is beneficial to saving cost and generating economic benefits.

Description

Technical Field

[0001] The invention relates to the field of iron ore blasting construction, in particular to a sedimentary metamorphic open-pit iron ore blasting method. Background Art

[0002] Boundary blasting has its unique particularity and importance in open-pit iron ore mining. Its main purpose is to ensure the stability of the final slope through precise control of blasting during the mining process. This is crucial to preventing geological disasters such as slope landslides and collapses, and is directly related to the normal production of the mine, the safety of equipment and personnel, and the economic benefits of the mine.

[0003] However, at present, when the initial blasting is carried out in the mine to form the pre-cracking line, in order to avoid the disturbance of the slope caused by the blasting, the blasting intensity is controlled by reducing the charge amount. However, it is difficult to ensure that the blasting purpose is fully achieved while avoiding slope disturbance by simply adjusting the charge amount, resulting in poor final blasting effect. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art in that the slope is disturbed and the stability of the slope is destroyed, and a method for blasting a sedimentary metamorphic open-pit iron ore by blasting is proposed.

[0005] In order to solve the problems existing in the prior art, the present invention adopts the following technical solutions:

[0006] A method for blasting sedimentary metamorphic open-pit iron ore, comprising the following steps:

[0007] S1. Drilling: According to the rock mass investigation results, select the appropriate drilling location to ensure that the pre-crack distribution position forms pre-cracks in the subsequent steps;

[0008] S2. Charge: Use segmented charge method to evenly distribute the ammonium oil explosive in the borehole and install the detonator;

[0009] S3, plugging: After the charge is completed, cement slurry and gravel are mixed to form a plugging material to tightly plug the main blast hole to prevent gas leakage during the explosion of explosives;

[0010] S4. Detonation: Send out a detonation signal to detonate the detonator, causing the explosive to explode in the main blast hole.

[0011] As a preferred technical solution of the present application, the S1 drilling type includes pre-splitting holes and main blasting holes. The pre-splitting holes are arranged at a predetermined pre-splitting line, which is arranged 1m away from the bottom line of the slope, and the main blasting holes are arranged in the bottom area close to the slope.

[0012] As a preferred technical solution of the present application, when the S1 drilling is carried out, the pre-splitting hole blasting area has a width not exceeding two rows of main blasting holes and a length not exceeding 50m.

[0013] As the preferred technical solution of the present application, the S2 charge is initially sprayed in the pre-crack hole formed by the S1 borehole, the spraying agent is ammonium oil explosive, and the initial blasting is carried out to form certain cracks inside the rock mass to form a pre-crack line, the charge density of the pre-crack line is adjusted from 0.7kg / m to 0.5kg / m, and is segmented into 10m sections, and the single-shot charge amount is controlled to be below 60kg.

[0014] As a preferred technical solution of the present application, the plugging material used in the S3 plugging, the sum of the filling outer diameter of the plugging material and the outer diameter of the detonating cap installed with the S2 charge is matched with the inner diameter clearance of the main blasting hole, and when the plugging material is filled in the S3 plugging, a pressure-assisted method is used to increase the filling density.

[0015] As the preferred technical solution of this application, it also includes:

[0016] S5. Post-blasting inspection: After the blasting is completed, wait for 5 to 15 minutes, and after the blasting smoke and dust dissipate, enter the blasting area for inspection.

[0017] As the preferred technical solution of the present application, the S5 post-blast inspection includes environmental inspection and data inspection. The environmental inspection includes on-site blasting effect detection, and the data inspection includes particle vibration velocity peak value, main vibration frequency, vibration duration, maximum flying stone scattering distance and noise value.

[0018] As the preferred technical solution of this application, it also includes:

[0019] S6. Clearance and transportation: Clean up and transport the blast piles produced by blasting, and set up dust-proof nets in the blasting area.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. In the S2 charging step of the present invention, the main blast hole formed in the S1 drilling step is sprayed with explosives for the first time and the initial blasting is carried out to form certain cracks inside the rock mass, i.e., a pre-splitting line. The pre-splitting line is arranged 1 m away from the bottom line of the slope to prevent the formation of an umbrella eave after the pre-splitting. The charging density of the pre-splitting line is adjusted from 0.7 kg / m to 0.5 kg / m, and the pre-splitting line is segmented into 10 m sections, and the single-shot charge is controlled to be below 60 kg. That is, by changing the wiring position, charging density and charging amount, the propagation range and intensity of the shock wave and stress wave generated during the blasting are appropriately reduced, which helps to reduce the direct impact and damage to the slope. In addition, this method can reduce the amount of explosives used, and ensure the expected blasting effect while saving costs.

[0022] 2. In the S2 charging step of the present invention, the blasting area is controlled so that the width does not exceed two rows of main blasting holes and the length does not exceed 50 meters, so as to control the impact of blasting on the stability of the slope, maintain the stability of the slope, and further ensure safe operation.

[0023] 3. In the S2 charging step of the present invention, ammonium nitrate oil explosive is adopted, and the characteristics of its low density and low fierceness are utilized to make the blasting energy caused during the pre-splitting line blasting smaller, and the degree of damage to the slope is lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0025] Figure 1 It is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only embodiments of a part of the present invention, rather than all embodiments.

[0027] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work should fall within the scope of protection of the present invention.

[0028] As described in the background technology, blasting in mines is currently prone to disturbing the slopes, destroying the stability of the slopes, and in severe cases causing the slopes to slide or collapse. The sliding or collapse of the slopes may trigger a series of secondary disasters, such as mudslides, floods, etc. These disasters will further expand the scope of impact and pose a threat to the safety of life and property of surrounding residents.

[0029] Embodiment: This embodiment provides a method for blasting sedimentary metamorphic open-pit iron ore. Figure 1 , specifically, the following steps are included:

[0030] S1. Drilling: According to the rock mass investigation results, select the appropriate drilling location to ensure that the pre-crack distribution position forms pre-cracks in the subsequent steps;

[0031] S2. Charge: Use segmented charge method to evenly distribute the ammonium oil explosive in the borehole and install the detonator;

[0032] S3, plugging: After the charge is completed, cement slurry and gravel are mixed to form a plugging material to tightly plug the main blast hole to prevent gas leakage during the explosion of explosives;

[0033] S4. Detonation: Send out a detonation signal to detonate the detonator, causing the explosive to explode in the main blast hole.

[0034] In a preferred embodiment, the S1 drilling type includes a pre-splitting hole and a main blasting hole, the pre-splitting hole is set at a predetermined pre-splitting line, the pre-splitting line is set at 1m from the bottom line of the slope, and the main blasting hole is set near the bottom area of ​​the slope;

[0035] Specifically, the pre-splitting line is arranged 1m away from the bottom line of the slope to ensure the stability of the slope after blasting and prevent the formation of umbrella eaves after pre-splitting. The pre-splitting line is set to buffer, reflect or absorb the blasting energy generated by the main blasting area, thereby controlling the scope and direction of the blasting and protecting the surrounding environment and buildings from damage.

[0036] In a preferred embodiment, when the S1 drilling is performed, the pre-splitting hole blasting area has a width not exceeding two rows of main blasting holes and a length not exceeding 50m;

[0037] Specifically, by strictly controlling the blasting area of ​​the pre-splitting line, the main purpose of the pre-splitting blasting is to form a continuous crack between the main blasting area and the retained area to reduce the damage of the main blasting to the retained rock mass. Limiting the width of the pre-splitting line to within two rows of main blasting holes helps to ensure the continuity and quality of the pre-cracks. A pre-splitting line that is too long may produce greater blasting vibrations and have an adverse impact on the surrounding environment. Limiting the length of the pre-splitting line to within 50 meters helps to reduce the intensity of blasting vibrations and protect the safety of surrounding facilities and the environment.

[0038] In a preferred embodiment, the S2 charge is first sprayed in the pre-splitting hole formed by the S1 drilling, and the spraying agent is ammonium oil explosive, and the first blasting is performed to form certain cracks inside the rock mass to form a pre-splitting line, and the charge density of the pre-splitting line is adjusted from 0.7kg / m to 0.5kg / m, and the pre-splitting line is segmented into 10m sections, and the single-shot charge is controlled to be less than 60kg;

[0039] Specifically, reducing the charge density of the pre-splitting line from 0.7kg / m to 0.5kg / m means that the amount of explosives in the main blast hole per meter is reduced, reducing the shock wave and detonation gas pressure generated by the blasting. The reduction in charge density will also lead to a reduction in the width and depth of the cracks, which may reduce the destructive effect on the surrounding rock mass and help protect the stability of the slope.

[0040] Divide the blasting operation into 10m sections and control the charge per blast to less than 60kg. This segmented blasting method helps reduce the seismic effect caused by blasting.

[0041] The use of ammonium nitrate explosive takes advantage of its low density and low intensity, which makes the blasting energy caused by the pre-splitting line blasting smaller and the degree of damage to the slope lower.

[0042] In a preferred embodiment, the plugging material used in the S3 plugging, the filling outer diameter of the plugging material and the outer diameter of the detonator installed in the S2 charge are matched with the inner diameter of the main blast hole, and the pressure-assisted method is used to improve the filling density when the plugging material is filled in the S3 plugging;

[0043] Specifically, the plugging material prevents the escape of gas and debris generated by blasting by filling the voids in the main blast hole, thereby improving blasting efficiency.

[0044] Embodiment 2: Based on Embodiment 1, this embodiment further includes:

[0045] S5. Post-blasting inspection: After the blasting is completed, wait for 5 to 15 minutes, and after the blasting smoke and dust dissipate, enter the blasting area for inspection.

[0046] As the preferred technical solution of the present application, the S5 post-blast inspection includes environmental inspection and data inspection. The environmental inspection includes on-site blasting effect detection, and the data inspection includes particle velocity peak value, main vibration frequency, vibration duration, maximum flying distance of flying rocks and noise value.

[0047] Specifically, during data inspection, the peak value of particle velocity reflects the intensity of vibration generated by blasting, and is an important indicator for evaluating the impact of blasting on the surrounding environment (such as slope stability and adjacent buildings); the main vibration frequency is the main frequency component that characterizes the blasting vibration wave, which helps to analyze the propagation characteristics and attenuation laws of the vibration wave; the vibration duration is the time from the start to the end of the blasting vibration, which is used to evaluate the impact of vibration on long-term stability; the maximum scattering distance of flying rocks is used to evaluate the potential threat range of flying rocks to personnel and equipment; the noise intensity reflects the noise level generated by blasting, ensuring that the blasting operation complies with environmental protection regulations and standards; the actual blasting effect in the on-site blasting effect detection and whether the data in the data inspection meets the standards are combined to comprehensively evaluate the effectiveness of the blasting plan, and judge the specific links that cause the actual blasting effect to be insufficient based on the data in the data inspection.

[0048] Embodiment 3: Based on Embodiment 1, this embodiment further includes:

[0049] S6. Clearance and transportation: Clean up and transport the blast piles produced by blasting, and set up dust-proof nets in the blasting area.

[0050] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for blasting sedimentary metamorphic open-pit iron ore, comprising the following steps: S1. Drilling: According to the rock mass investigation results, select the appropriate drilling location to ensure that the pre-splitting hole distribution position forms the pre-splitting line in the subsequent steps; S2. Charge: Use segmented charge method to evenly distribute the ammonium oil explosive in the borehole and install the detonator; S3, plugging: After the charge is completed, cement slurry and gravel are mixed to form a plugging material to tightly plug the main blast hole to prevent gas leakage during the explosion of explosives; S4. Detonation: Send out a detonation signal to detonate the detonator, causing the explosive to explode in the main blast hole.

2. A sedimentary metamorphic open-pit iron ore blasting method according to claim 1, characterized in that: The S1 drilling type includes pre-splitting holes and main blasting holes. The pre-splitting holes are set at a predetermined pre-splitting line, which is set 1m away from the bottom line of the slope. The main blasting holes are set in the bottom area close to the slope.

3. The method for blasting sedimentary metamorphic open-pit iron ore according to claim 1, characterized in that: When the S1 drilling is carried out, the pre-splitting blasting area has a width not exceeding two rows of main blasting holes and a length not exceeding 50m.

4. The method for blasting sedimentary metamorphic open-pit iron ore according to claim 1, characterized in that: The S2 charge is first sprayed in the pre-crack hole formed by the S1 borehole. The spraying agent is ammonium oil explosive, and the initial blasting is carried out to form certain cracks inside the rock mass to form a pre-crack line. The charge density of the pre-crack line is adjusted from 0.7kg / m3 to 0.5kg / m3, and the pre-crack line is segmented into 10m sections, and the single-shot charge amount is controlled to be below 60kg.

5. The method for blasting sedimentary metamorphic open-pit iron ore according to claim 1, characterized in that: The plugging material used in the S3 plugging has a filling outer diameter, and the sum of the outer diameter of the detonating cap installed with the S2 charge is matched with the inner diameter clearance of the main blasting hole. When the plugging material is filled in the S3 plugging, a pressure-assisted method is used to improve the filling density.

6. The method for blasting sedimentary metamorphic open-pit iron ore according to claim 1, characterized in that: Also includes: S5. Post-blasting inspection: After the blasting is completed, wait for 5 to 15 minutes, and after the blasting smoke and dust dissipate, enter the blasting area for inspection.

7. A sedimentary metamorphic open-pit iron ore blasting method according to claim 6, characterized in that: The S5 post-blast inspection includes environmental inspection and data inspection. The environmental inspection includes on-site blasting effect detection, and the data inspection includes particle vibration velocity peak value, main vibration frequency, vibration duration, maximum flying distance of flying rocks and noise value.

8. The method for blasting sedimentary metamorphic open-pit iron ore according to claim 1, characterized in that: Also includes: S6. Clearance and transportation: Clean up and transport the blast piles produced by blasting, and set up dust-proof nets in the blasting area.

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