Surface mine stratified rock bench blasting charging structure and construction method thereof

Abstract

The invention relates to the technical field of surface mine blasting, and discloses a surface mine stratified rock bench blasting charging structure and a construction method of the surface mine stratified rock bench blasting charging structure. A large-diameter blast hole penetrating through a hard rock stratum and a weak intercalated layer is formed in the stratified rock mass of the surface mine in the vertical direction, the large-diameter blast hole comprises an orifice blank section, a hole bottom filling section and a charging section located between the orifice blank section and the hole bottom filling section, the horizontal position of the charging section corresponds to the hard rock stratum, and a detonating tube is arranged in the large-diameter blast hole. The detonating tube extends into the charging section on the bottommost layer from the hole opening blank section, a plurality of initiating explosive packages located in the charging section are arranged on the detonating tube, and the initiating explosive packages are used for detonating explosives filled in the charging section. According to the method, a more advanced borehole television system can be utilized, so that blast holes in a stope area are transparent, the stratified rock mass geologic structure is accurately known, the blasting effect is good, the boulder rate is reduced, and then the energy consumption of the whole operation link of a mine is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of open-pit mine blasting, and more particularly to an open-pit mine layered rock step blasting charge structure and a construction method thereof. Background Art

[0002] In open-pit mining, roads, water conservancy projects, construction and other projects, with the continuous improvement of drilling equipment and transportation equipment, deep hole step blasting has been widely used. In particular, in recent years, the blasting sharing theory has been proposed in the field of open-pit mining. This theory is to use precise blasting and scientific allocation to reduce rock blockiness and the control method of comprehensive energy consumption of the entire mining industry chain. This theory has played a significant role in improving the energy efficiency of multiple key links such as drilling, blasting, shoveling, transportation and mechanical crushing in mining operations. Based on the blasting sharing theory, the reasonable arrangement of the blasthole charge structure, the location of the detonation point and the detonation time can make the explosive energy reasonably distributed in time and space, ensuring the uniform distribution of blasting energy, and the quality of blasting directly affects the energy consumption of subsequent shoveling, transportation and mechanical crushing. During the blasting process, the more uniform and stable the properties of the blasting medium are, the better the blasting effect will be. However, for layered rock masses, the rock properties fluctuate greatly, and there may be weak interlayers between adjacent rock layers. Due to long-term geological and geostress effects, microscopic damage and macroscopic structural surfaces have been generated in the layered rock mass, and its deformation and strength have obvious anisotropic characteristics, resulting in extremely unbalanced energy distribution inside the layered rock mass during the blasting process, and the stress wave energy decays more rapidly, wasting the efficiency of the explosive gas. If traditional methods are used for blasting, it is difficult to control the blasting quality. In the traditional blasting technology, the difference of rock properties in the vertical direction of the layered rock structure is not taken into account. During the blasting process, the detonation gas is easy to leak in the weak interlayer, resulting in poor blasting effect. The phenomenon of high block rate, root, side pull, back pull, flying stone and irregular blast pile often occurs, resulting in high secondary crushing cost and difficult to ensure safety. However, the existing research results are difficult to realize the visualization of blasting and drilling. There are few studies on this issue, for example: [Application No.] 201710767717.2, [Application Date] 2017.0 8.31, [Name] Blast hole charging structure and method for deep hole step blasting of soft and hard mixed layered rock mass, this method uses drilling and coring to understand the rock formation, the operation is complicated and it is difficult to quickly and efficiently obtain rock formation information; for example: [Application number] 202011165174.5, [Application date] 2020.10.27, [Name] A mining method for accurate delayed in-situ blasting and crushing of layered rock mass, this method only relies on the original geological data of the mine to analyze the geological structure of the mining step, it is impossible to accurately understand the specific structure of the blast hole, and it is not universal. Therefore, there is an urgent need for a step blasting method with good blasting effect for layered rock mass. Summary of the invention

[0003] In view of this, in order to better solve the technical problem in the existing technical environment that in the deep hole blasting of layered rock steps, the blasting medium properties in the vertical direction of the rock mass fluctuate greatly, resulting in the leakage of detonation energy, resulting in poor blasting effect and high rate of large blocks, thereby affecting the total energy consumption of the subsequent shoveling and crushing processes, the present invention provides a layered rock step blasting charging structure and a construction method for an open-pit mine, which can utilize a more advanced drilling television system to make the blastholes in the mining area transparent, accurately understand the geological structure of the layered rock mass, achieve good blasting effect, reduce the rate of large blocks, and thus reduce the energy consumption of the overall operation of the mine.

[0004] To achieve the above-mentioned purpose, the present invention provides a step blasting charging structure for layered rock mass in an open-pit mine, comprising hard rock layers and weak interlayers alternately distributed in the vertical direction, wherein the layered rock mass in the open-pit mine is provided with large-diameter blastholes penetrating the hard rock layers and the weak interlayers in the vertical direction, wherein the large-diameter blastholes include a blank section at the orifice, a filling section at the bottom of the hole, and a charging section for filling explosives located therebetween, wherein the horizontal position of the charging section corresponds to the hard rock layer, and the number of the charging sections is equal to the number of layers of the hard rock layer, wherein two adjacent charging sections are separated by gun mud, and the vertical length of the gun mud covers the position of the weak interlayer, wherein a detonating cord is arranged in the large-diameter blasthole, wherein the detonating cord extends from the blank section at the orifice to the charging section at the bottom layer, wherein the detonating cord is provided with a plurality of detonating charges located in the charging section, and wherein the detonating charges are used to detonate the explosives filled in the charging section.

[0005] Preferably, the explosive at the top of the charging section is 2 to 5 cm away from the weak interlayer, and a non-explosion cavity area and a compaction area are provided on the weak interlayer to reduce the layer cracking effect of the rock mass containing the weak interlayer.

[0006] Preferably, a small diameter blast hole is arranged between two adjacent large diameter blast holes, the depth of the small diameter blast hole is one fifth of the depth of the large diameter blast hole, and the charge structure of the small diameter blast hole is the same as that of the large diameter blast hole.

[0007] The construction method of the layered rock step blasting charging structure in an open-pit mine provided by the present invention comprises the following steps: T1. Blast hole position marking and drilling: Mark the positions of blast holes in the layered rock area of ​​the open-pit mine, set up drilling machinery at the marked positions of the blast holes in the stope, and drill holes to obtain a corresponding number of large-diameter blast holes; T2. Collecting stratum conditions: The stratum conditions in the blasthole are collected through borehole television, including the layered rock structure, the thickness and occurrence of hard rock layers, whether there are weak interlayers between hard rock layers, and the integrity of hard rock layers; T3. Analyze the collected information: Analyze the images sent back by the borehole TV detection, and obtain the thickness of the layered rock mass, the inclination and dip of the joints and fissures, and whether there are weak interlayers based on the information collected by the borehole TV; T4. Charge: Charge large diameter blastholes according to the stratigraphic structure information obtained by the borehole TV. Charge sections are set at corresponding positions in each hard rock layer. Explosives are filled in the charge sections, and adjacent charge sections are separated by gun mud. T5. Blasting: After the large-diameter blastholes are charged, micro-difference blasting is carried out according to the detonation plan to complete the blasting operation. After the blasting is completed, the block size analysis is carried out on the blasted ore pile.

[0008] Preferably, step T2 comprises the following steps: Carry a drilling TV into the detection area. The drilling TV includes a drilling TV host, a transmission line, and a drilling TV probe. Connect the drilling TV probe, the transmission line, and the drilling TV host in sequence, and electrically connect the drilling TV probe to the depth recorder on the top of the supporting tripod. After the installation is completed, put the drilling TV probe into the borehole. The drilling TV probe is provided with an LED light and a camera electrically connected to the drilling TV host. The wall of the borehole is illuminated by the LED light, and then the camera records the reflected wall image and transmits it to the drilling TV host through the data transmission wire. The display of the drilling TV host can be used to perform real-time imaging and record the depth of the borehole; Preferably, the drilling television further comprises a drilling depth rotating winch and a stabilizing device. The drilling depth rotating winch is arranged between the transmission line and the drilling TV probe, and is used to release the transmission line at a uniform speed, so that the drilling TV probe slowly descends into the borehole. The stabilizing device is installed at the top of the borehole TV probe to ensure that the borehole TV probe always maintains a vertical state during the downward exploration process.

[0009] Preferably, step T3 comprises the following steps: The borehole television imager processes the acquired information of the borehole wall and depth of the large-diameter blasthole to form two kinds of borehole wall images, one is a three-dimensional image of the core, and the other is a two-dimensional unfolded tiled image of the borehole wall.

[0010] Preferably, step T4 comprises the following steps: According to the analysis results of the distribution of layered rock masses by drilling television, the charging structure of each large-diameter blasthole is set up, charging sections are set up at corresponding positions in each hard rock layer, explosives are filled in the charging sections, and gun mud is used to separate the charging sections, and the length of the separation covers the location of the weak interlayer.

[0011] Preferably, in step T5, a plum blossom-shaped or V-shaped detonation method is used for detonation.

[0012] Preferably, in step T1, small diameter blast holes are added between adjacent large diameter blast holes to reduce the bulk rate at the blank section of the orifice of the large diameter blast hole.

[0013] It can be seen from the above technical scheme that, compared with other existing layered rock blasthole charging methods, the layered rock step blasting charging structure and construction method disclosed in the present invention make the borehole transparent by using a drilling television, thereby reducing the high rate of large blocks, roots, side pulls, back pulls, flying rocks, and irregular blast piles caused by uneven blasting energy distribution and leakage during layered rock mining, thereby reducing the secondary processing cost. At the same time, the present invention also has the following beneficial effects: 1. Simple construction, the geological conditions of the layered rock mass in the blasthole can be obtained through drilling television, eliminating the complicated operation of drilling and coring; 2. The presentation effect is intuitive. Borehole TV can display the acquired stratum information and depth information in real time through two-dimensional or three-dimensional images; 3. Wide applicability. This method is not only suitable for rock drilling and blasting processes in open-pit mines, but can also be used for underground mines or other projects involving drilling and blasting. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0015] Figure 1 It is a schematic diagram of the working process of the construction method of the layered rock step blasting charging structure in an open-pit mine of the present invention; Figure 2 This is a schematic diagram of the installation of a TV with a drilled hole according to the present invention; Figure 3 It is a schematic diagram of the charge structure for step blasting of layered rock mass in an open-pit mine of the present invention; Figure 4 It is a partial enlarged view of the charge structure for step blasting of layered rock mass in an open-pit mine according to the present invention.

[0016] Explanation of the reference numerals: 1-drilling TV host; 2-transmission line winch; 3-transmission line; 4-tripod; 5-depth recorder; 6-drilling TV probe; 7-stabilizing device; 8-hard rock layer; 9-weak interlayer; 10-blank section at the hole mouth; 11-detonating cord; 12-explosive package; 13-gun mud; 14-bottom hole filling section; 15-charging section. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Please see attached Figure 1-4 , which is the open-pit mine layered rock step blasting charging structure and construction method disclosed by the present invention.

[0019] like Figure 3-4 As shown, the layered rock step blasting charging structure for an open-pit mine provided by the present invention includes a hard rock layer 8, a weak interlayer 9, a hole mouth blank section 10, a detonating cord 11, an explosive package 12, taphole mud 13, a hole bottom filling section 14, and a charging section 15.

[0020] The hard rock layer 8 and the weak interlayer 9 are alternately distributed in the vertical direction. The layered rock mass of the open-pit mine is provided with large-diameter blastholes penetrating the hard rock layer 8 and the weak interlayer 9 in the vertical direction. The orifice portion of the large-diameter blasthole at the upper end is a blank orifice section 10, and the bottom of the hole at the lower end is divided into a hole bottom filling section 14. The portion between the blank orifice section 10 and the hole bottom filling section 14 is formed into several sections of charging sections 15 for filling explosives and gun mud 13 for separating adjacent charging sections 15. The horizontal position of the charging section 15 corresponds to the hard rock layer 8, and the number of the charging sections 15 corresponds to the hard rock layer 8. The number of layers 8 is equal, and two adjacent charging sections 15 are separated by gun mud 13. The vertical length of the gun mud 13 covers the position of the weak interlayer 9. A detonating cord 11 is arranged in the large-diameter blasthole. The detonating cord 11 extends from the blank section 10 at the hole mouth to the charging section 15 at the bottom layer. In order to detonate the explosive filled in the charging section 15, a plurality of detonating packages 12 are arranged on the detonating cord 11. Each charging section 15 is correspondingly provided with a detonating package 12. Each detonating package 12 is ignited by the detonating cord 11, thereby detonating the explosive filled in each charging section 15.

[0021] It should be noted that the layered rock mass includes hard rock layers 8 and weak interlayers 9 between the hard rock layers 8. The hard rock layers 8 and the weak interlayers 9 are generally arranged alternately from bottom to top. The thickness and inclination angle of the rock layers can be measured by the drilling television. A charging section 15 is arranged in the middle of the hard rock layer 8. The charging section 15 is filled with medicine rolls or other types of explosives. A filling section is arranged between the charging sections 15 to ensure that the intervals between the hard rock layers 8 are not filled with explosives, so as to prevent the explosion energy from leaking through the intervals or the weak interlayers 9, resulting in low utilization of the blasting energy and a high rate of large blocks.

[0022] Specifically, in order to avoid the existence of air gaps or weak interlayers 9 between the hard rock layers 8 and the hard rock layers 8 in the layered rock mass, thereby pushing the surrounding rock mass under the action of the blasting load, causing the subsequent displacement of the surrounding rock mass, and the phenomenon of explosion rejection is prone to occur at the interlaced surface of the rock layers due to the distance between the upper and lower layers of explosives exceeding the sympathetic detonation distance, after using the in-hole television to obtain the rock layer information, the explosives can be accurately placed in the charging section 15 corresponding to the hard rock layer 8 and fixed with gun mud 13 to prevent displacement.

[0023] It should be noted that the distance between the explosive at the top of the charging section 15 and the weak interlayer 9 is 2 to 5 cm, and a non-explosion cavity area and a compaction area are set on the weak interlayer 9 to reduce or overcome the layer cracking effect of the rock mass containing the weak interlayer 9.

[0024] Specifically, the explosives of the charging section 15 should be appropriately away from the weak interlayer 9 when they are set. As the explosive package moves away from the weak interlayer 9, the explosion-free cavity area and the compaction area of ​​the weak interlayer 9 are continuously reduced. When the explosives at the top of the charging section are 2 to 5 cm away from the weak interlayer, the influence of the explosion-generated gas on the interlayer is effectively controlled, thereby reducing or overcoming the block-like layer cracking phenomenon of the rock mass containing the weak interlayer.

[0025] In order to further optimize the above technical scheme, a small-diameter blasthole is arranged between two adjacent large-diameter blastholes. The depth of the small-diameter blasthole is one-fifth of the depth of the large-diameter blasthole, and the charging structure of the small-diameter blasthole is the same or similar to that of the large-diameter blasthole. The purpose is to reduce the problem of insufficient blasting of the top rock mass, resulting in a high rate of large blocks.

[0026] like Figure 1 As shown, the construction method of the layered rock step blasting charge structure in an open-pit mine provided by the present invention performs in-hole detection by means of a borehole television in the early stage to obtain high-definition image information in the geological borehole, realizes the identification of the occurrence information of the rock joint surface, determines the layered rock structure, the thickness and occurrence of the hard rock layer, whether there are weak interlayers between the hard rock layers, the integrity of the hard rock layer, etc.; designs the blasthole charge according to the details of the stratum structure obtained by the borehole television, sets a charge section 15 at the corresponding position in each hard rock layer 8, fills the charge section 15 with explosives, and Adjacent charge sections 15 are separated by taphole mud 13 or other filling materials, and the main action area of ​​the detonation gas generated by the explosive blasting is controlled within the explosion cracks formed between the hard rock layers 8 due to the blasting action, so that most of the explosion energy acts on the broken rock mass instead of leaking through weak interlayers 9, primary structural surfaces and other weak surfaces; on the basis of the original hole network parameters, small-diameter blastholes are added between adjacent large-diameter blastholes to reduce the large block rate of the normal blasthole mouth part, and then the plum blossom or V-shaped detonation method is used for detonation. Specifically, the following steps are included: Step T1, blasthole position marking and drilling: Mark the positions of blastholes in the stope of the layered rock mass area of ​​the open-pit mine, so that the blastholes in the stope are divided into large-diameter blastholes and small-diameter blastholes for the convenience of drilling operations. The large-diameter blastholes are arranged according to the normal stope design, and the small-diameter blastholes are arranged between adjacent large-diameter blastholes. The depth of the blastholes is one-fifth of the depth of the large-diameter blastholes; Set up drilling machinery at the marked position of the blasthole in the stope to drill holes. After the drilling is completed, check the quality of the holes to see if there are any blockages or water seepage, and deal with them in time; It should be noted that small-diameter blast holes need to be supplemented between adjacent large blast holes based on actual conditions.

[0027] Step T2, collecting formation conditions: collecting formation conditions in the blasthole through the borehole television, including layered rock structure, hard rock layer thickness, occurrence, whether there are weak interlayers between hard rock layers, and hard rock layer integrity. The borehole television includes a borehole television host 1, a drilling depth rotating winch 2, a transmission line 3, and a borehole television probe 6.

[0028] Specifically, Figure 2 As shown, carry the drilling TV equipment into the detection area, connect the drilling TV probe 6, the transmission line 3, and the drilling TV host 1 in sequence, and electrically connect the drilling TV probe 6 to the depth recorder 5 on the top of the supporting tripod 4. After the installation is completed, put the drilling TV probe 6 into the borehole, rotate the winch 2 according to the borehole depth to release the transmission line 3 at a uniform speed, so that the drilling TV probe 6 slowly goes down into the borehole, and the top of the probe is equipped with a stabilizing device 7 to ensure that the probe always remains in a vertical state during the downward exploration process; the wall of the borehole is illuminated by the LED light on the drilling TV probe 6, and then the camera in the drilling TV probe 6 records the reflected wall image and transmits it to the observation drilling TV host 1 through the data transmission wire (transmission line 3), and the drilling TV host 1 display can be used to perform real-time imaging and record the depth of the borehole; after the detection work is completed, the transmission line 3 can be recovered by rotating the winch 2 according to the borehole depth, and the drilling TV probe 6 can be slowly taken out of the borehole; In order to further optimize the above technical solution, the release speed of the borehole television probe 6 should be controlled at 2 to 3 meters per minute during the lowering process. Too fast a speed will cause the generated geological information image to be blurred. The maximum detection depth of the borehole television can be changed according to the actual blasthole depth in on-site production. By increasing the length of the transmission line 3, it can adapt to blastholes of different depths. Usually, a bundle of winches can carry 50 meters of data cable.

[0029] Step T3, analyzing the collected information: Analyze the images sent back by the borehole TV detection. The borehole TV imager can process the collected borehole wall and depth information to form two types of borehole wall images. One is a three-dimensional image of the core, which can be rotated at any angle to observe the core, and the other is a two-dimensional unfolded flat image of the borehole wall. According to the data measured by the borehole TV, the thickness of the layered rock mass, the inclination and dip of the joints and fissures, and whether there are weak interlayers and other information can be obtained; It should be noted that the images transmitted back by the borehole TV can be directly reviewed in the borehole TV host 1, and the data can also be imported into a computer for more detailed identification. In the computer, not only can the existence of joints, cracks and voids be identified, but a schematic diagram of the borehole deviation can also be directly generated, which is more convenient for subsequent charging.

[0030] Step T4, charging: design the charging structure of each blasthole according to the analysis of the distribution of layered rock mass after drilling TV detection. The charging structure of the blasthole should follow the following principles: First, a charging section 15 is set at a corresponding position in each hard rock layer 8, and explosives are filled in the charging section; second, the charging sections are separated by taphole mud 13, and the length of the separation needs to cover the position of the weak interlayer 9; third, the distance between the top explosive of the charging section 15 and the weak interlayer 9 is 2 to 5 cm, and a non-explosion cavity area and a compaction area are set on the weak interlayer 9, which can reduce or overcome the layer cracking effect of the rock mass containing the weak interlayer 9; fourth, for the small-diameter blastholes between adjacent large-diameter blastholes, the charging structure is similar to that of the large-diameter blastholes, the purpose of which is to reduce the problem of insufficient blasting of the top rock mass, resulting in a high rate of large blocks; It should be noted that a hole bottom filling section 14 needs to be provided at the hard rock layer at the bottom of the blasthole.

[0031] In order to further optimize the above technical solution, if conditions permit, the taphole mud 13 used to separate the charging section 15 can be replaced with a water column bag. The water column bag can not only prevent the detonation gas generated by the explosion of the explosives from escaping with the weak interlayer and reducing the explosion energy loss, but also effectively suppress the dust pollution generated by the explosion.

[0032] Step T5, blasting: after the blasthole is charged, micro-difference blasting is performed according to the detonation plan to complete the blasting operation. The detonation can be performed in a plum blossom or V-shaped detonation mode. After the blasting is completed and the smoke is cleared and the safety alert is lifted, the block size of the blasted ore pile is analyzed to determine the blasting effect. In order to further optimize the above technical solution, the blasting network design can be carried out hole by hole, row by row, segmented within the hole, with the rear row facing the slope and the explosive charge on the top of the blast hole being detonated later.

[0033] It should be noted that: 1. Before using the drilling TV for drilling each time, the device needs to be fully charged in advance to prevent the construction progress from being slowed down due to insufficient power; 2. Before lowering the drilling TV probe into the blast hole, be sure to check the stability of the body connector and the connection between the release mechanism and the probe to avoid the probe equipment falling off during the lowering process, causing unnecessary economic losses.

[0034] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A charge structure for step blasting of layered rock mass in an open-pit mine, characterized in that: The invention relates to a layered rock mass of an open-pit mine, wherein the layered rock mass is provided with large-diameter blastholes penetrating the hard rock layer (8) and the soft interlayer (9) in the vertical direction. The large-diameter blastholes include a hole mouth blank section (10), a hole bottom filling section (14), and a charge section (15) for filling explosives therebetween. The horizontal position of the charge section (15) corresponds to the hard rock layer (8), and the number of the charge sections (15) corresponds to the number of layers of the hard rock layer (8). The two adjacent charge sections (15) are separated by gun mud (13), the vertical length of the gun mud (13) covers the location of the weak interlayer (9), a detonating cord (11) is arranged in the large-diameter blasthole, and the detonating cord (11) extends from the blank section (10) at the hole mouth to the charge section (15) at the bottom layer, and a plurality of detonating packages (12) located in the charge section (15) are arranged on the detonating cord (11), and the detonating packages (12) are used to detonate the explosive filled in the charge section (15).

2. The open-pit mine layered rock step blasting charging structure according to claim 1 is characterized in that: The explosive at the top of the charging section (15) is 2 to 5 centimeters away from the weak interlayer (9), and a non-explosion cavity area and a compaction area are provided on the weak interlayer (9) to reduce the layer cracking effect of the rock mass containing the weak interlayer (9).

3. The open-pit mine layered rock step blasting charging structure according to claim 1 is characterized in that: A small diameter blast hole is arranged between two adjacent large diameter blast holes, the depth of the small diameter blast hole is one fifth of the depth of the large diameter blast hole, and the charge structure of the small diameter blast hole is the same as that of the large diameter blast hole.

4. A construction method for a layered rock step blasting charge structure in an open-pit mine as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: T1. Blast hole position marking and drilling: Mark the positions of blast holes in the layered rock area of ​​the open-pit mine, set up drilling machinery at the marked positions of the blast holes in the stope, and drill holes to obtain a corresponding number of large-diameter blast holes; T2. Collecting stratum conditions: The stratum conditions in the blasthole are collected through borehole television, including the layered rock structure, the thickness and occurrence of hard rock layers, whether there are weak interlayers between hard rock layers, and the integrity of hard rock layers; T3. Analyze the collected information: Analyze the images sent back by the borehole TV detection, and obtain the thickness of the layered rock mass, the inclination and dip of the joints and fissures, and whether there are weak interlayers based on the information collected by the borehole TV; T4, charging: charging the large diameter blasthole according to the stratum structure information obtained by the borehole television, setting a charging section (15) at a corresponding position in each hard rock layer (8), filling the charging section (15) with explosives, and separating adjacent charging sections (15) with gun mud (13); T5. Blasting: After the large-diameter blastholes are charged, micro-difference blasting is carried out according to the detonation plan to complete the blasting operation. After the blasting is completed, the block size analysis is carried out on the blasted ore pile.

5. The construction method of the layered rock step blasting charge structure in an open-pit mine according to claim 4 is characterized in that: The step T2 comprises the following steps: Carry a drilling TV into the detection area. The drilling TV comprises a drilling TV host (1), a transmission line (3), and a drilling TV probe (6). The drilling TV probe (6), the transmission line (3), and the drilling TV host (1) are connected in sequence, and the drilling TV probe (6) is electrically connected to a depth recorder (5) on the top of a supporting tripod (4). After the installation is completed, the drilling TV probe (6) is placed inside the borehole. The drilling TV probe (6) is provided with an LED light and a camera electrically connected to the drilling TV host (1). The wall of the borehole is illuminated by the LED light, and then the camera records the reflected wall image and transmits it to the drilling TV host (1) through the data transmission wire. The display of the drilling TV host (1) can be used to perform real-time imaging and record the depth of the borehole.

6. The construction method of the layered rock step blasting charging structure in an open-pit mine according to claim 5, characterized in that: The drilling television also includes a drilling depth rotating winch (2) and a stabilizing device (7). The drilling depth rotating winch (2) is arranged between the transmission line (3) and the drilling TV probe (6) and is used to release the transmission line (3) at a uniform speed so that the drilling TV probe (6) slowly descends into the borehole. The stabilizing device (7) is installed at the top of the borehole television probe (6) and is used to ensure that the borehole television probe (6) always maintains a vertical state during the downward exploration process.

7. The construction method of the layered rock step blasting charge structure in an open-pit mine according to claim 4, characterized in that: The step T3 comprises the following steps: The borehole television imager processes the acquired information of the borehole wall and depth of the large-diameter blasthole to form two kinds of borehole wall images, one is a three-dimensional image of the core, and the other is a two-dimensional unfolded tiled image of the borehole wall.

8. The construction method of the layered rock step blasting charge structure in an open-pit mine according to claim 4, characterized in that: The step T4 comprises the following steps: According to the analysis results of the distribution of layered rock mass by the borehole television, the charging structure of each large-diameter blasthole is set, and a charging section (15) is set at a corresponding position in each hard rock layer (8). The charging section (15) is filled with explosives, and the charging sections (15) are separated by gun mud (13), and the length of the separation covers the position of the weak interlayer (9).

9. The construction method of the layered rock step blasting charge structure in an open-pit mine according to claim 4, characterized in that: In step T5, detonation is performed by using a plum blossom or V-shaped detonation method.

10. The construction method of the layered rock step blasting charge structure in an open-pit mine according to claim 4, characterized in that: In the step T1, small diameter blast holes are added between adjacent large diameter blast holes to reduce the bulk rate at the blank section (10) at the mouth of the large diameter blast holes.

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