A method for medium-length hole blasting with stepped charge structure

Abstract

The application discloses a kind of middle-deep hole blasting method with stepped charge structure, steps include being arranged in the rock drilling lane upwards multiple rows of blast hole groups and is divided into several blasting periods, each row of blast hole group is arranged several blast holes, the last row of blast hole of each blasting period adopts the charge structure of 5-8 meters of hole mouth leaving empty, the first row of blast hole of non-first blasting period adopts full-hole charge, the rest row normal charge, form the stepped charge structure of blast hole in single blasting period, each row of blast hole group is arranged in the order of middle first, then both sides, and the first explosion interval of adjacent row is 65ms, after blasting, 35-40% of ore is extracted, and the next operation period is entered.The application arranges the blast hole charge structure in single blasting period into stepped type and uses hole-by-hole blasting process, forms stepped eyebrow line in front of the first row of blast hole of next blasting period, has the characteristics of less ore during blasting, can concentrate, continuous blasting, concentrate ore, greatly reduces the recovery period, and has high operation safety and small influence on the outside world.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of mining, and particularly relates to a middle-deep hole blasting method adopting a step-type charging structure. BACKGROUND

[0002] The middle-deep hole blasting method is one of the most commonly used mining methods in underground mining. The conventional blasting mode of the middle-deep hole blasting method generally takes 3-4 rows as one blasting cycle, and each row of blast holes in each blasting cycle is blasted by using a full-height blasting charging structure, that is, the length of the charging of each blast hole is determined by the intersection point of the blasting U-shaped area with a certain preset radius, and the preset radius L of the U-shaped area is usually half of the preset maximum hole bottom distance value. However, this blasting mode usually has many defects in actual operation: first, due to the use of full-height blasting, the single-row blast hole charging amount is large, and the first row of blast holes of the next blasting cycle is easily damaged by the vibration wave of the previous blasting cycle, which reduces the stability of the brow line port (the intersection area of the blasted ore falling area and the unblasted area) and affects the safety of operation; second, the ore of the previous blasting cycle is easily accumulated in the brow line port and the drilling roadway at the brow line port, and usually 60-70% of the ore quantity of the current blasting cycle needs to be removed to make the first row of blast holes of the next blasting cycle have the conditions for charging operation. A large amount of ore removal often leads to the formation of a goaf above the brow line port, which is prone to the risk of falling or collapsing of the rock, and it is difficult to ensure the safety of the ore removal shovel personnel, equipment, and the charging personnel of the next blasting cycle, and safety accidents often occur. At the same time, a large amount of ore removal usually requires a long ore removal time, for example, if 3 rows are taken as one blasting cycle, it usually takes 3-4 days to remove 60-70% of the ore quantity of one blasting cycle, and other operations cannot be carried out during the ore removal period, which cannot realize continuous blasting, thereby prolonging the start time of the next blasting cycle, lengthening the single mine room recovery cycle, and reducing the mining efficiency and timeliness.

[0003] In addition, the existing middle-deep hole blasting method usually uses a 3-section blasting mode, and the single-row blasting is first performed on the middle 3-4 blast holes by low-position initiation, and then the two sides of the blast holes are initiated by using the interval 1-section detonator; when multiple rows of blast holes are blasted, the first blast section of the rear row of blast holes must be 3 section higher than that of the front row of blast holes, for example, if 3 rows are simultaneously initiated, the first row of detonator section is 1 section, 2 section and 3 section, the second row of detonator section is 4 section, 5 section and 6 section, and the third row of detonator section is 7 section, 8 section and 9 section. This initiation mode requires a long initiation cycle, a large amount of single blasting, a high single response, a large ground and ground building vibration, and frequent interruptions or impact on the mining operation schedule due to complaints from the public, which seriously restricts the mining efficiency. SUMMARY

[0004] In order to overcome the problems of poor eyebrow line stability, large ore output, low operation safety factor, long blasting cycle and poor timeliness of the existing medium-length hole blasting method, the present application provides a medium-length hole blasting method using a stepped charge structure, which has the advantages of less ore output in a cycle, concentrated blasting, continuous blasting, concentrated ore output, short stoping cycle, high operation safety, high production timeliness, low single response, small external influence and the like.

[0005] The present application is realized by the following technical solutions:

[0006] The present application provides a medium-length hole blasting method using a stepped charge structure, which comprises the following implementation steps:

[0007] S1, arranging blast holes: a plurality of rows of blast hole groups are drilled upward in the rock drilling roadway, and each row of blast hole groups is arranged with a plurality of blast holes;

[0008] S2, setting a blasting cycle: 3-4 rows of blast hole groups are taken as one blasting cycle, and all blast holes in a single blasting cycle complete charging operation and concentrated blasting at one time;

[0009] S3, first blasting cycle operation: the last row of blast hole groups is filled with explosives by using a charging structure of charging from the bottom of the hole to leaving a 5-8m empty space at the hole mouth, wherein the empty space length is determined according to the lithology, such as 5-6m deep for hard lithology, 6-7m for medium lithology, and 7-8m for broken lithology; the remaining rows of blast hole groups are filled with explosives by using a charging length mode determined according to the minimum overlap principle of the blasting area, forming a first-order charging structure of the first blasting cycle; after the blasting operation is started and the ore is dropped, the ore is discharged until the first row of blast holes of the next blasting cycle is exposed, and then the ore discharge is stopped;

[0010] S4, second blasting cycle operation: the first row of blast hole groups is filled with explosives by using a full-hole charging structure from the bottom of the hole to the hole mouth, the last row of blast hole groups is filled with explosives by using the same charging structure as the last row of blast hole groups in S3, and the remaining rows of blast hole groups are filled with explosives by using a charging length mode determined according to the minimum overlap principle of the blasting area, forming a two-order charging structure of the second blasting cycle; after the blasting operation is started and the ore is dropped, the ore is discharged until the first row of blast holes of the next blasting cycle is exposed, and then the ore discharge is stopped;

[0011] S5, repeating S4 until the last remaining blasting cycle;

[0012] S6, last blasting cycle operation: the first row of blast hole groups is filled with explosives by using the same charging structure as the first row of blast hole groups in S4, and the remaining rows of blast hole groups are filled with explosives by using a charging length mode determined according to the minimum overlap principle of the blasting area, forming a first-order charging structure of the last blasting cycle, and starting the blasting and ore dropping operation;

[0013] S7, ore discharge: after the ore is dropped in S6, the concentrated ore discharge of the entire stope is organized, and the stoping operation of the stope is ended.

[0014] Based on the above technical scheme, after each blasting cycle completes blasting and ore drawing, a step-shaped brow line opening can be formed in front of the first row of blast holes of the next blasting cycle, and ore drawing is performed at the next blasting cycle. On the one hand, most of the ore entering the drilling roadway can be left in the roadway below the step-shaped brow line opening, and a small amount of ore can reach the charging condition of the first row of blast holes of the next blasting cycle, thereby greatly compressing the blasting cycle. On the other hand, the step-shaped brow line opening can form a good protective barrier, so that the ore drawing operation and the charging operation of the next cycle are both in the roadway, avoiding exposure operations below the goaf, and the safety guarantee coefficient is high, effectively avoiding safety accidents.

[0015] Further, the ore drawing amount in steps S3 and S4 is 35-40% of the ore drawing amount of the current blasting cycle.

[0016] Further, the explosives filled in each blast hole in steps S3, S4 and S6 are emulsified granular ammonium oil explosives, and a detonation bullet is arranged at the bottom of the hole. The detonation bullet is assembled from a half emulsified explosive and a single digital electronic detonator, which realizes the bottom detonation of each blast hole, is beneficial to the superposition of explosion shock waves to improve the blasting effect and improve the blasting success rate. Further, the number of each row of blast hole groups in step S1 is determined according to the stope width and the preset hole bottom distance, and the angles of the two side holes (i.e. the outermost blast holes) are not less than 45°. The number of adjacent rows of blast holes is set to an adjacent value, and adjacent rows of blast holes are arranged in an odd-even row intersection manner.

[0017] Further, the angle of the two side holes is 50° so that the blasted rock can smoothly enter the drilling roadway, and the preset hole bottom distance is 2.6-2.8 m to minimize the amount of explosives used in blasting and to meet the requirement that the size of the blasted ore meets the requirements, thereby saving mining costs.

[0018] Further, the concentrated blasting mode in step S2 is a single-row blast hole group using a hole-by-hole blasting process, and an adjacent row of blast hole groups uses a delay blasting process to reduce the maximum single response and reduce the amount of ground vibration.

[0019] Further, when the number of single-row blast holes is odd, the hole-by-hole blasting process in step S2 is to first detonate a single blast hole at the center position, and then sequentially detonate the blast holes on the left and right sides of the center blast hole in a jumping manner.

[0020] Further, when the number of single-row blast holes is even, the hole-by-hole blasting process in step S2 is to first detonate two blast holes at the center position simultaneously, and then sequentially detonate the blast holes on the left and right sides of the center blast hole in a jumping manner.

[0021] Further, the interval of the left and right jumping detonation in the hole-by-hole blasting process is 20 ms.

[0022] Further, the delay blasting process in the step S2 is that the interval time of the first blasting of the adjacent row hole group in each blasting period is not less than 65 ms.

[0023] Advantages

[0024] One of the above technical solutions has the following advantages or beneficial effects:

[0025] 1) To solve the problems of poor stability of the eyebrow line port, low safety factor of operation and long recovery period and poor timeliness in the existing medium-length hole blasting method, the present application arranges the multiple rows of blast holes in each blasting period into a stepped charge structure and then performs blasting, so that after a small amount of ore is blasted out in a single period, a stepped eyebrow line port is formed in front of the first row of hole groups in the next blasting period. On the one hand, most of the ore entering the drilling roadway stays in the roadway below the stepped eyebrow line port, and 35-40% of the ore can reach the charging conditions for the next blasting, greatly compressing the blasting period and shortening the recovery period of the entire stope by 3-4 times, meeting the requirements of "strong mining, strong output, and strong charging; fast mining, fast output, and fast charging". On the other hand, the stepped eyebrow line port can form a good protective barrier, so that the ore extraction operation and the charging operation of the next period are all in a safe roadway, avoiding exposure operations below the goaf, and the safety factor of the operation is high, which can effectively prevent accidents from occurring, and has the characteristics of short blasting period, concentrated blasting and ore extraction, short recovery period, high operation safety, high production efficiency, and fast economic benefits.

[0026] 2) By cross-arranging the blast holes in odd and even rows, and using the hole-by-hole blasting process of first center and then two sides jump initiation for single-row blast holes, the single response during blasting operation is effectively reduced, the superposition effect of the blasting shock wave is weakened, and the vibration amplitude of the ground around the stope is reduced, so as to reduce the disturbance risk during continuous mining operation and ensure the continuity of the mining operation. BRIEF DESCRIPTION OF DRAWINGS

[0027] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0028] Figure 1 It is a schematic diagram of the overall stepped charge structure of the present application;

[0029] Figure 2 It is a schematic diagram of the eyebrow line port of a certain blasting period of the present application;

[0030] Figure 3 It is a schematic diagram of the blast hole arrangement in step S3 of the present application;

[0031] Figure 4 It is a schematic diagram of the blast hole arrangement structure in step S4 of the present application;

[0032] Figure 5 The schematic diagram of the hole mouth blank loading structure of the last row of blast holes of the present application;

[0033] Figure 6 The schematic diagram of the full hole loading structure of the first row of blast holes of the present application;

[0034] In the figure: rock tunnel 100; blast hole 10; stemming 1; blank section 2; emulsified granular ammonium oil explosive 3; detonator head 4. DETAILED DESCRIPTION

[0035] The present application will be further described in detail below in conjunction with examples, but the embodiments of the present application are not limited thereto.

[0036] The present application provides a kind of middle-deep hole blasting method using step type loading structure, comprising the following implementation steps:

[0037] S1, layout blast hole: a plurality of rows of blast hole groups are drilled upward in the rock tunnel, each row of blast hole group contains a plurality of blast holes, the number of each row of blast hole group is determined according to the width of the stope and the preset hole bottom distance, and the layout angle of the two side holes is not less than 45°, the number of blast holes in adjacent rows is set to adjacent value, and the blast holes in adjacent rows are arranged in an odd-even row crossing manner, that is, an odd number of blast holes are arranged in an odd row, and an adjacent even number of blast holes are arranged in an even row, or an even number of blast holes are arranged in an odd row, and an adjacent odd number of blast holes are arranged in an even row, the blast holes in the odd row and the even row are arranged with the rest of the blast holes in the two side holes, that is, the non-edge blast hole in the adjacent row is not overlapped, preferably, the layout angle of the two side holes is set to 50° so that the rock after blasting can smoothly enter the rock tunnel, and the preset hole bottom distance is set to 2.6-2.8 m to reduce the amount of explosive used as much as possible and meet the requirements of the size of the ore after blasting, thereby saving the mining cost.

[0038] S2, set the blasting period: 3-4 rows of blast hole groups are taken as one blasting period, all blast holes in a single blasting period complete the loading operation at one time and are blasted in a centralized manner, the centralized blasting mode is that single-row blast hole groups use the hole-by-hole blasting process, and adjacent row blast hole groups use the delay blasting process, wherein the hole-by-hole blasting process is: when the number of blast holes in a single row is odd, one blast hole at the center position of the low position is preferentially initiated, and then the two side blast holes are sequentially initiated in a left-right jumping manner with an initiation interval of 20 ms; when the number of blast holes in a single row is even, two blast holes at the center position of the low position are preferentially initiated at the same time, and then the two side blast holes are sequentially initiated in a left-right jumping manner with an initiation interval of 20 ms; the delay blasting process is: the first blasting interval time of adjacent two rows of blast holes in each blasting period is not less than 65 ms.

[0039] S3, first blasting cycle operation: the holes in the last row are filled with explosives with a charging structure that charges from the bottom to the hole opening, leaving 5-8 meters of no charge, and 50 cm of stemming is filled at the end of the explosive section of the hole opening, wherein the length of the left empty is determined according to the lithology, such as the length of the left empty can be 5-6 meters deep for hard lithology, 6-7 meters for medium lithology, and 7-8 meters for broken lithology; the holes in the remaining rows are filled with explosives with a charging length determined by the principle of minimum overlap of the blasting area (i.e. the full-height blasting charging structure described in the background art), forming a first-order charging structure of the first blasting cycle; the initiation network is set according to the initiation interval in step S2, and the hole bottom initiation operation is performed on each hole, and after the ore is dropped, 35-40% of the ore quantity of the current blasting cycle is removed, and the mining is stopped after the first row of holes of the next blasting cycle is exposed;

[0040] S4, second blasting cycle operation: the holes in the first row are filled with explosives with a full-hole charging structure from the bottom to the hole opening, and 50 cm of stemming is filled at the hole opening, the charging structure of the holes in the last row is the same as that of the holes in the last row in S3, and the holes in the remaining rows are filled with explosives with a charging length determined by the principle of minimum overlap of the blasting area, forming a two-order charging structure of the second blasting cycle; the initiation network is set according to the initiation interval in step S2, and the hole bottom initiation operation is performed on each hole, and after the ore is dropped, 35-40% of the ore quantity of the current blasting cycle is removed, and the mining is stopped after the first row of holes of the next blasting cycle is exposed;

[0041] S5, repeat S4 until the last remaining blasting cycle;

[0042] S6, last blasting cycle operation: the charging structure of the first row of holes is the same as that of the first row of holes in S4, and the charging structure of the remaining rows of holes is determined by the principle of minimum overlap of the blasting area, forming a first-order charging structure of the last blasting cycle, and the initiation network is set according to the initiation interval in step S2, and the hole bottom initiation operation is performed on each hole, and the ore is dropped;

[0043] S7, ore removal: after the ore is dropped in S6, the entire ore in the stope is removed, and the stoping operation of the stope is completed.

[0044] Further, in the above steps S3, S4 and S6, the explosives filled in each hole are emulsified granular ammonium oil explosives, and a detonator head is provided at the bottom of the hole, the detonator head is assembled by placing a half emulsion explosive and a single digital electronic detonator in the detonator head shell to realize the hole bottom initiation of each hole, which is beneficial to the superposition of explosive shock waves to improve the blasting effect and improve the blasting success rate;

[0045] A specific embodiment based on the above technical solution is:

[0046] S1, layout blast hole: drill a drill roadway 100 in a 15m wide stope, and drill a plurality of rows of blast hole groups upward along the axis direction of the drill roadway 100, each row of blast hole groups contains a plurality of blast holes 10, the number of each row of blast hole groups is determined as 9 and 10 according to the 15m stope width and the preset hole bottom distance of 2.6-2.8m, wherein the two side holes of each row of blast hole groups are laid out at an angle of 50°, and specifically, as shown in Figure 3 , Figure 4 , the number of blast holes in the odd row blast hole group is set to 9, and the number of blast holes in the even row blast hole group is set to 10;

[0047] S2, set the blasting period: as shown in Figure 1 , take 3 rows of blast hole groups as one blasting period, all blast holes in each blasting period complete charging operation at one time and concentrate blasting, the concentration blasting mode is that single row of blast hole groups adopt hole-by-hole blasting process, and adjacent rows of blast hole groups adopt delay blasting process, as shown in Figure 3 or Figure 4 , when the odd row blast hole group is blasted, the centermost blast hole 10 is set as 0ms initiation segment, low position initiation is preferentially performed, and then the initiation segment is set in the left-right-left-right mode in turn, one blast hole 10 is initiated at an interval of 20ms each time until the blasting of all blast holes 10 is completed; when the even row blast hole group is blasted, the two blast holes 10 close to the center are both set as 0ms initiation segment, low position initiation is performed at the same time, and then the initiation segment is set in the left-right-left-right mode in turn, one blast hole 10 is initiated at an interval of 20ms each time until the blasting of all blast holes 10 is completed; at the same time, the initiation time interval of the 0ms initiation blast hole (i.e. the first initiation segment) of adjacent odd and even rows of blast hole groups in the same blasting period is set to 65ms, as shown in

[0048] S3, first blasting period operation: the 1st-3rd row of blast hole groups are set as the first blasting period (i.e. Figure 1 S3 blasting period), as shown in Figure 3 , the 1st and 2nd row of blast hole groups are both determined by the intersection point of the blast U-shaped area with a radius of 1.2m to determine the charging length of each blast hole, then the emulsified granular ammonium nitrate fuel oil explosive 3 is filled, and a half of the emulsified explosive and a digital electronic detonator constitute an initiation bullet 4 at the bottom of the hole; as shown in Figure 5As shown, in the third row, all boreholes 10 are charged with explosives after the detonating warhead 4 is placed at the bottom of the hole, extending to a distance of 5-8 meters from the hole opening, and then sealed with 50cm of stemming material 1. A blank section 2 is left uncharged below the stemming material, forming a first-order charge structure for the first blasting cycle. A detonation network is set up according to the detonation interval in step S2, and bottom detonation is performed on each borehole 10. After the ore falls, 35-40% of the current ore volume is cleared until the charging conditions for the first row of boreholes 10 in the second blasting cycle are met, forming a structure as shown in the diagram. Figure 2 The stepped eyebrow line opening shown is 20;

[0049] S4. Second blasting cycle operation: Set up rows 4-6 of boreholes for the second blasting cycle (i.e., Figure 1 As shown in the S4 blasting cycle), such as Figure 6 As shown, after placing the detonating warhead 4 at the bottom of the fourth row of boreholes 10, the entire borehole from bottom to top is filled with emulsified granular ammonium nitrate explosive 3, and the borehole opening is sealed with 50cm of stemming mud 1. The fifth row of boreholes 10 adopts the same charging structure as the first row in S3, and the sixth row of boreholes 10 adopts the same charging structure as the third row in S3, forming a second-order charging structure for the second blasting cycle. The detonation network is set up according to the detonation interval in step S2, and bottom detonation is performed on each borehole 10. After the ore is dropped, 35-40% of the current ore volume is cleared until the charging conditions of the first row of boreholes 10 in the next blasting cycle are met, forming a structure as shown in the figure. Figure 2 The stepped eyebrow line opening shown is 20;

[0050] S5. Continue with a blasting cycle of 3 rows of blast holes (i.e.) Figure 1 (As shown in S5-1 and S5-n blasting cycles), repeat step S4 until the last blasting cycle remains, that is, until the last 3 rows of blasting holes 10 remain.

[0051] S6. Final Blasting Cycle Operation: The last three rows of boreholes are set as the final blasting cycle (i.e., Figure 1 As shown in S6 blasting cycle, the first row of boreholes in the final blasting cycle is filled with explosives according to the charging structure of the 4th row in S4, and the remaining rows of boreholes are filled with explosives according to the charging structure of the 1st row in S3, forming a first-order charging structure for the final blasting cycle. The detonation network is set up according to the detonation interval in step S2, and bottom detonation is performed on each borehole 10, waiting for the ore to fall.

[0052] S7. Mining: After the ore is extracted, organize the centralized extraction of all the ore in the entire mining area to end the mining operation in that mining area.

[0053] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A medium-deep hole blasting method employing a stepped charge structure, characterized in that... The implementation steps include the following: S1. Laying out blast holes: Several rows of blast hole groups are drilled upward in the rock drilling tunnel, and several blast holes are laid out in each row of blast hole groups. S2. Setting the blasting cycle: A blasting cycle consists of 3-4 rows of boreholes. Within a single blasting cycle, all boreholes are charged and blasted simultaneously. The concentrated blasting method involves blasting each borehole in turn for a single row, while adjacent rows of boreholes are blasted using a delayed blasting method. When the number of boreholes in a single row is odd, the blasting process involves first detonating the single borehole at the center position, and then sequentially detonating the boreholes on either side of the center borehole in a left-right skipping manner. When the number of boreholes in a single row is even, the blasting process involves first simultaneously detonating the two boreholes at the center position, and then sequentially detonating the boreholes on either side of the center borehole in a left-right skipping manner. S3. First blasting cycle operation: The last row of blast holes is loaded with explosives using a loading structure that starts from the bottom of the hole and leaves a 5-8 meter gap at the hole opening. The remaining rows of blast holes are loaded with explosives using the principle of minimum overlap of the blasting zone to determine the loading length. This forms the first-order loading structure for the first blasting cycle. Blasting operation is then started. After the ore is extracted, ore extraction is stopped once the first row of blast holes for the next blasting cycle is exposed. S4. Second blasting cycle operation: The first row of blast holes is filled with explosives using a full-hole charging structure from the bottom to the opening. The charging structure of the last row of blast holes is the same as that of the last row of blast holes in S3. The remaining rows of blast holes are filled with explosives according to the principle of minimum overlap of the blasting zone to determine the charging length, forming a second-order charging structure for the second blasting cycle. The blasting operation is started, and the ore is extracted after the ore is dropped. Extraction is stopped after the first row of blast holes of the next blasting cycle is exposed. S5. Repeat S4 until the last blasting cycle remains; S6. Final blasting cycle operation: The charge structure of the first row of blast holes is the same as that of the first row of blast holes in S4. The remaining rows of blast holes are filled with explosives according to the principle of minimum overlap of the blasting zone to determine the charge length, forming a first-order charge structure for the final blasting cycle, and the blasting and ore-dropping operation is started. S7. Mining: After the ore is mined in S6, organize the centralized mining of all the ore in the entire mining area and end the mining operation in that mining area.

2. The method for medium-deep hole blasting using a stepped charge structure according to claim 1, characterized in that: The ore output in steps S3 and S4 is 35-40% of the ore output in the current blasting cycle.

3. The medium-deep hole blasting method using a stepped charge structure according to claim 1, characterized in that: In steps S3, S4 and S6, the explosives filled into each borehole are emulsified granular ammonium nitrate explosives, and a detonating warhead is set at the bottom of the borehole. The detonating warhead is assembled from half a strip of emulsified explosive and a single digital electronic detonator.

4. The medium-deep hole blasting method using a stepped charge structure according to claim 1, characterized in that: In step S1, the number of borehole groups in each row is determined according to the width of the mining area and the preset bottom distance of the boreholes, and the angle of the side holes on both sides is not less than 45°. The number of boreholes in adjacent rows is set as adjacent values, and the boreholes in adjacent rows are arranged in an alternating pattern of odd and even rows.

5. A medium-deep hole blasting method using a stepped charge structure according to claim 4, characterized in that: The side holes are arranged at an angle of 50°, and the preset hole bottom distance is 2.6~2.8m.

6. A medium-deep hole blasting method using a stepped charge structure according to claim 1, characterized in that: The left-right jump detonation interval in the hole-by-hole blasting process is 20ms.

7. A medium-deep hole blasting method using a stepped charge structure according to claim 1, characterized in that: The delayed blasting process in step S2 involves an interval of no less than 65ms between the first blasts of adjacent blast hole groups within each blasting cycle.

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