A method for demolishing a high concrete foundation pit of a large open-pit mine crushing station

Abstract

The present application belongs to the technical field of open-pit mine blasting demolition, and particularly relates to a large open-pit mine crushing station high and large concrete foundation pit demolition method, and the specific steps are as follows: S1: preparation work; S2: determining the concrete foundation pit parameters; S3: blasting design; S4: first blasting: (1) drilling operation; (2) charge and detonator arrangement; (3) blasting time difference; (4) observing the blasting effect; S5: second blasting: (1) drilling operation; (2) charge and detonator arrangement; (3) blasting time difference; (4) checking the demolition result. The method uses down-the-hole drilling and digital detonator precise control through layer blasting, greatly shortens the high and large concrete foundation pit demolition time, and improves the demolition efficiency; through precise control of drilling parameters, charge structure and blasting time sequence, using hole micro-difference blasting, drilling and step hole blasting time difference, effectively reduces the flying stone risk, reduces the influence on the surrounding facilities, and ensures the operation safety.

Description

Technical Field

[0001] This invention belongs to the field of open-pit mine blasting and demolition technology, and particularly relates to a method for demolishing a tall concrete foundation pit of a large open-pit mine crushing station. Background Technology

[0002] In large-scale open-pit mining operations, the demolition of tall concrete foundation pits for semi-mobile crushing stations is a challenging engineering task. Traditional demolition methods, such as mechanical crushing, are inefficient and costly, and take a long time to demolish foundation pits of 15m or more. Conventional blasting methods suffer from problems such as unreasonable drilling parameters and poor control of blasting time difference, which can easily lead to poor blasting results (such as insufficient crushing of the foundation pit and high risk of flyrock) and significant impact on surrounding facilities. Summary of the Invention

[0003] The purpose of this invention is to provide a method for demolishing tall concrete foundation pits in large open-pit mine crushing stations, which solves the problems of unreasonable drilling parameters, poor control of blasting time difference leading to poor blasting effect, and great impact on surrounding facilities caused by conventional blasting methods.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A method for dismantling a tall concrete foundation pit in a large open-pit mine crushing station, the specific steps of which are as follows: S1: Preparations Remove the crushing station's vehicle stopper, clear the original terrain, level the work site, install fall protection devices on the upper part of the pit, and reserve a 10-15m solid step around the pit.

[0005] S2: Determine the parameters of the concrete foundation pit The original topography of the concrete foundation pit and its surrounding area was measured. Based on the foundation pit construction drawings and geological maps, the geometric and structural parameters of the foundation pit were accurately determined, and the parameters of the backfill material between the foundation pit and the solid structure were determined. A three-dimensional model was drawn based on the parameters of the foundation pit, backfill material, and surrounding solid structure.

[0006] S3: Explosive Design The 3Dmine mining engineering software is used to design perforation and blasting based on three-dimensional graphics.

[0007] S4: First Detonation (1) Drilling operations; (2) Arrangement of explosives and detonators; (3) Detonation time difference; (4) Observe the blasting effect.

[0008] S5: Second Detonation (1) Drilling operations; (2) Arrangement of explosives and detonators; (3) Detonation time difference; (4) Inspect the demolition results.

[0009] Preferably, the specific content of the drilling operation in step S4 (1) is as follows: Drill holes in the upper part of the concrete foundation pit using a down-the-hole drill. The hole diameter is 115 or 140 mm, the hole spacing is 2-5 m, the row spacing is 2-5 m, the hole depth is 7-15 m, and the bottom of the hole should not exceed the depth limit.

[0010] Preferably, the specific details of the charging and detonator arrangement in step S4 (2) are as follows: Fill with ammonium nitrate fuel oil explosive, and backfill the top with crushed stone material for 2.5-5m; place two digital detonators in the hole, with the bottom detonator 1-2m from the bottom of the hole and the two detonators 3-5m apart vertically. Utilize micro-delay blasting in the hole, with the lower detonator detonating 20-30 milliseconds earlier than the upper detonator.

[0011] Preferably, the specific details of the blasting time difference in step S4 (3) are as follows: Arrange 2-4 rows of central holes on the step behind the foundation pit, with a hole spacing of 3-5m, a row spacing of 3-5m, and a backfill of 3.5-5m. Fill with ammonium nitrate oil explosives. The central holes and the foundation pit boreholes are detonated in sequence according to the time difference. Set the concrete foundation pit boreholes to be blasted 30-50 milliseconds ahead of the central holes on the step behind the foundation pit.

[0012] Preferably, the specific details of observing the blasting effect in step S4 (4) are as follows: After detonation, observe the blasting effect to confirm that the upper 10-15m of the foundation pit is sufficiently broken, the lower part of the foundation pit is undamaged, and the surrounding facilities are undamaged. Record the blasting parameters and effect data, and carry out the excavation work.

[0013] Preferably, the specific content of the drilling operation in step S5 (1) is as follows: After cleaning and leveling the concrete foundation pit, the borehole layout was re-established based on the outline of the foundation pit and the parameters of the borehole network from the first blasting. The second borehole was drilled to an extra depth of 1-2m, with the hole depth adapted to the demolition of the remaining structure in the foundation pit.

[0014] Preferably, the specific details of the charging and detonator arrangement in step S5 (2) are as follows: The ammonium nitrate fuel oil explosive is loaded. Following the detonator layout logic of the first blast, two digital detonators are used. The bottom detonator is 1-2m from the bottom of the hole, and the vertical spacing between the two detonators is 3-5m. Micro-delay blasting is used in the hole, with the lower detonator detonating 20-30 milliseconds earlier than the upper detonator. The details of the pit depth and structural adjustment are combined with the second blast.

[0015] Preferably, the specific details of the blasting time difference in step S5 (3) are as follows: Two to four rows of central holes are arranged on the bench behind the foundation pit, with a hole spacing of 3-5m, a row spacing of 3-5m, and a backfill of 3.5-5.5m. Ammonium nitrate oil explosives are loaded. The central holes and the foundation pit boreholes are detonated in sequence according to the time difference. The blasting of the concrete foundation pit is still 30-50 milliseconds ahead of the blasting of the central holes on the bench behind the foundation pit. This ensures coordination with the overall blasting rhythm of the mine and ensures continuous and orderly mining operations.

[0016] Preferably, the specific content of checking the demolition results in step S5 (4) is as follows: After detonation, the demolition results were checked to confirm that the foundation pit had been fully demolished and the surrounding facilities were undamaged. The blasting parameters and effect data were recorded, and the clearing and excavation work was carried out.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: (1) Compared with mechanical crushing, layered blasting utilizes down-the-hole drills and digital detonators for precise control, which greatly shortens the demolition time of tall concrete foundation pits and improves demolition efficiency. (2) By precisely controlling the drilling parameters, charge structure and blasting sequence, and utilizing the in-hole micro-delay blasting and the time difference between drilling and bench blasting, the risk of flying rocks can be effectively reduced, the impact on surrounding facilities can be minimized, and operational safety can be ensured. (3) Using the commonly used down-the-hole drilling equipment in open-pit mines, no additional large-scale demolition equipment is required; the cost of ammonium nitrate explosives is relatively controllable; layered blasting is compatible with the existing blasting material supply and usage system in mines, reducing the overall cost of demolition operations; (4) The timing of concrete pit blasting and bench blasting is coordinated to ensure smooth connection between mining and demolition operations, without additional interference with the mining production process, and to improve the overall operational efficiency of the mine. Attached Figure Description

[0018] Figure 1 This is a plan view and borehole layout diagram of the first demolition of blasted concrete in an embodiment of the present invention; Figure 2 This is a plan view and borehole layout diagram of the second demolition blasting of concrete in an embodiment of the present invention. Detailed Implementation

[0019] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments. Example 1

[0020] A large open-pit mine needs to demolish a 21m high semi-mobile crushing station concrete foundation pit. This invention provides a method for demolishing a tall concrete foundation pit of a large open-pit mine crushing station. The specific steps are as follows: S1: Preparations Remove the vehicle stopper at the crushing station, clear the original terrain, level the work site, install a fall arrest device on the upper part of the pit, and reserve a 15m solid step around the pit.

[0021] S2: Determine the parameters of the concrete foundation pit The original topography of the concrete foundation pit and its surrounding area was measured. Based on the foundation pit construction drawings and geological maps, the geometric and structural parameters of the foundation pit were accurately determined, and the parameters of the backfill material between the foundation pit and the solid structure were determined. A three-dimensional model was drawn based on the parameters of the foundation pit, backfill material, and surrounding solid structure.

[0022] S3: Explosive Design The 3Dmine mining engineering software is used to design perforation and blasting based on three-dimensional graphics.

[0023] S4: First Detonation (1) such as Figure 1 As shown, a down-the-hole drill was used to drill holes in the upper part of the foundation pit with a diameter of 115mm, a hole spacing of 3m, and a row spacing of 3m, with a drilling depth of 10m. (2) Fill the hole with ammonium nitrate explosive and backfill the top with 3m of crushed stone; place two digital detonators, with the bottom detonator 2m from the bottom of the hole and the two detonators 3m apart vertically, and set the lower detonator to detonate 20 milliseconds earlier than the upper one. (3) Two rows of central holes are arranged on the steps behind the foundation pit, with a hole spacing of 3m, a row spacing of 3m, and a backfill of 4m. Ammonium nitrate explosives are loaded. The central holes and the foundation pit boreholes are detonated in sequence according to the time difference. The first blast of the concrete foundation pit is set to be 40 milliseconds ahead of the blast of the central holes on the steps behind the foundation pit. (4) After detonation, observe the blasting effect, confirm that the upper 10m part of the foundation pit is fully broken, the lower part of the foundation pit is undamaged, and the surrounding facilities are undamaged. Record the blasting parameters and effect data, and carry out the excavation work.

[0024] S5: Second Detonation (1) such as Figure 2 As shown, after leveling the remaining surface of the foundation pit, a down-the-hole drill with a diameter of 115mm was used to drill a hole 12m deep, according to the hole network parameters of the first blasting, based on the scope of the foundation pit. (2) Repeated loading of ammonium nitrate oil explosives, backfilling, and detonator arrangement. Two digital detonators are used, with the bottom detonator 2m from the bottom of the hole and the vertical distance between the two detonators 3m. The micro-delay blasting inside the hole is utilized, and the lower detonator detonates 20 milliseconds earlier than the upper detonator. (3) Arrange three rows of central holes in the step behind the foundation pit, with a hole spacing of 3m, a row spacing of 3m, and a backfill of 4m. Fill them with ammonium nitrate explosives. The central holes and the foundation pit boreholes are detonated in sequence according to the time difference. Set the second blast of the concrete foundation pit to be 40 milliseconds ahead of the blast of the central holes in the step behind the foundation pit. (4) After detonation, check the demolition results, confirm that the foundation pit has been fully demolished and the surrounding facilities have not been damaged, record the blasting parameters and effect data, and carry out the clearing and excavation work.

[0025] S6: Overall Effect Verification The demolition time and cost (equipment usage, blasting materials, explosive consumption, etc.) were statistically analyzed, and the coordination between concrete foundation pit demolition blasting and mining production was evaluated. It was confirmed that this method can achieve efficient, safe and economical demolition in actual projects and can be promoted and applied.

Claims

1. A method for demolishing a high concrete foundation pit of a large open-pit mine crushing station, characterized in that, The specific steps are as follows: S1: Preparations Remove the car stopper at the crushing station, clear the original terrain, level the work site, install a fall protection device on the upper part of the pit, and reserve a 10-15m solid step around the pit. S2: Determine the parameters of the concrete foundation pit The original topography of the concrete foundation pit and its surrounding area was measured. Based on the foundation pit construction drawings and geological maps, the geometric and structural parameters of the foundation pit were accurately determined, and the parameters of the backfill material between the foundation pit and the solid structure were determined. A three-dimensional model was drawn based on the parameters of the foundation pit, backfill material, and surrounding solid structure. S3: Explosive Design Using 3Dmine mining engineering software to design perforation and blasting based on three-dimensional graphics; S4: First Detonation (1) Drilling operations; (2) Arrangement of explosives and detonators; (3) Detonation time difference; (4) Observe the blasting effect; S5: Second Detonation (1) Drilling operations; (2) Arrangement of explosives and detonators; (3) Detonation time difference; (4) Inspect the demolition results.

2. The method for demolishing a high concrete foundation pit of a large open-pit mine crushing station according to claim 1, characterized in that, The specific details of the drilling operation in step S4 (1) are as follows: Drill holes in the upper part of the concrete foundation pit using a down-the-hole drill. The hole diameter is 115 or 140 mm, the hole spacing is 2-5 m, the row spacing is 2-5 m, the hole depth is 7-15 m, and the bottom of the hole should not exceed the depth limit.

3. The method for demolishing a high concrete foundation pit of a large open-pit mine crushing station according to claim 2, characterized in that, The specific details of the charging and detonator arrangement in step S4 (2) are as follows: Fill with ammonium nitrate fuel oil explosive, and backfill the top with crushed stone material for 2.5-5m; place two digital detonators in the hole, with the bottom detonator 1-2m from the bottom of the hole and the two detonators 3-5m apart vertically. Utilize micro-delay blasting in the hole, with the lower detonator detonating 20-30 milliseconds earlier than the upper detonator.

4. The method for demolishing a high concrete foundation pit of a large open-pit mine crushing station according to claim 3, characterized in that, The specific details of the blasting time difference in step S4 (3) are as follows: Arrange 2-4 rows of central holes on the step behind the foundation pit, with a hole spacing of 3-5m, a row spacing of 3-5m, and a backfill of 3.5-5m. Fill with ammonium nitrate oil explosives. The central holes and the foundation pit boreholes are detonated in sequence according to the time difference. Set the concrete foundation pit boreholes to be blasted 30-50 milliseconds ahead of the central holes on the step behind the foundation pit.

5. The method for demolishing a high concrete foundation pit of a large open-pit mine crushing station according to claim 4, characterized in that, The specific details of observing the blasting effect in step S4 (4) are as follows: After detonation, observe the blasting effect to confirm that the upper 10-15m of the foundation pit is sufficiently broken, the lower part of the foundation pit is undamaged, and the surrounding facilities are undamaged. Record the blasting parameters and effect data, and carry out the excavation work.

6. The method for demolishing a high concrete foundation pit of a large open-pit mine crushing station according to claim 5, characterized in that, The specific details of the drilling operation in step S5 (1) are as follows: After cleaning and leveling the concrete foundation pit, the borehole layout was re-established based on the outline of the foundation pit and the parameters of the borehole network from the first blasting. The second borehole was drilled to an extra depth of 1-2m, with the hole depth adapted to the demolition of the remaining structure in the foundation pit.

7. The method for demolishing a high concrete foundation pit of a large open-pit mine crushing station according to claim 6, characterized in that, The specific details of the charging and detonator arrangement in step S5 (2) are as follows: The ammonium nitrate fuel oil explosive is loaded. Following the detonator layout logic of the first blast, two digital detonators are used. The bottom detonator is 1-2m from the bottom of the hole, and the vertical spacing between the two detonators is 3-5m. Micro-delay blasting is used in the hole, with the lower detonator detonating 20-30 milliseconds earlier than the upper detonator. The details of the pit depth and structural adjustment are combined with the second blast.

8. The method for demolishing a high concrete foundation pit of a large open-pit mine crushing station according to claim 7, characterized in that, The specific details of the blasting time difference in step S5 (3) are as follows: Two to four rows of central holes are arranged on the bench behind the foundation pit, with a hole spacing of 3-5m, a row spacing of 3-5m, and a backfill of 3.5-5.5m. Ammonium nitrate oil explosives are loaded. The central holes and the foundation pit boreholes are detonated in sequence according to the time difference. The blasting of the concrete foundation pit is still 30-50 milliseconds ahead of the blasting of the central holes on the bench behind the foundation pit. This ensures coordination with the overall blasting rhythm of the mine and ensures continuous and orderly mining operations.

9. A method for demolishing a high concrete foundation pit of a large open-pit mine crushing station according to claim 8, characterized in that, The specific details of checking the demolition results in step S5 (4) are as follows: After detonation, the demolition results were checked to confirm that the foundation pit had been fully demolished and the surrounding facilities were undamaged. The blasting parameters and effect data were recorded, and the clearing and excavation work was carried out.

Images