A stope ore drawing method by combined blasting of pre-splitting blast holes and downward fan-shaped blast holes

Abstract

The present application discloses a stope ore drawing method for combined blasting of pre-splitting blast holes and downward fan-shaped blast holes. The method includes: dividing the ore body to be mined into stopes in two steps according to the mining sequence. In the two stopes, stope connecting laneways, drilling laneways and ore drawing laneways are respectively constructed, and a pre-support is provided by a long cable bolt and bolt support system. In the drilling laneway of the first-step stope, a cutting cross-heading and a bottom-drawing cross-heading are constructed, and a first cutting slot is formed by blasting, providing a necessary free face and compensation space for subsequent downward fan-shaped blast hole blasting. Downward fan-shaped blast holes and pre-splitting blast holes are constructed in the drilling laneway of the first-step stope, while only pre-splitting blast holes are constructed in the drilling laneway of the second-step stope. Explosives are loaded into the downward fan-shaped blast holes and each pre-splitting blast hole in the first-step stope, and blasting is carried out in sequence. After blasting, the stope is washed with the gas flowing through the ore drawing laneway to discharge the foul gas, and then the residual ore is removed and the goaf is backfilled.

Description

Technical Field

[0001] The present application relates to the technical field of metal mining, and in particular to a method for blasting ore in a stope by combining blasting of pre-splitting blastholes with downward fan-shaped blastholes. Background Art

[0002] At present, the open-pit subsequent filling mining method mainly adopts the method of downward vertical hole drilling and lateral blasting in the mining area. The downward vertical hole drilling has the advantages of uniform blasting energy distribution, small blasting block size, and controllable mining area blasting boundary, but it has the disadvantages of large exposed area of ​​the drilling chamber roof, great difficulty in controlling ground pressure, and poor drilling safety. Deep mining has become an important part of the mining industry. The mining of deep metal ores with thick and large ore bodies is mined under special conditions of strong disturbance and high ground pressure. If the traditional downward vertical hole drilling is still used for the mining of deep metal ores with thick and large ore bodies, it will lead to the collapse of the roof of the deep mining area drilling chamber, difficulty in support, and large loss and depletion of ore, which will seriously restrict the safe and efficient mining of deep mineral resources.

[0003] In recent years, with the development of rock drilling equipment, the rock drilling problem of downward fan-shaped holes has been solved. The use of downward fan-shaped hole drilling instead of downward vertical hole drilling will turn the top rock drilling chamber into a rock drilling tunnel. The rock drilling tunnel has the advantages of small roof exposure area and simple ground pressure control, which can greatly improve the safety of rock drilling operations and is more suitable for deep metal ore mining. In addition, downward fan-shaped hole drilling also has the advantages of small mining engineering volume, flexible blasthole arrangement, less movement of rock drilling equipment, short rock drilling auxiliary time, easy filling body bearing, and reduced stress concentration on the roof of the mining area. Therefore, downward fan-shaped hole drilling has important application prospects in deep metal ore mining.

[0004] However, downward fan-shaped hole drilling blasting has the problem of difficulty in controlling the blasting boundary of the stope, and the stope is seriously over-excavated and under-excavated. Summary of the invention

[0005] In view of this, an embodiment of the present application provides a method for dropping ore into a mine by combining blasting of pre-splitting blastholes with downward fan-shaped blastholes. By introducing the combined blasting technology of pre-splitting blastholes and downward fan-shaped blastholes, the advantages of pre-splitting blasting and downward fan-shaped blasting are fully utilized without adding additional mining approval engineering, thereby ensuring the smoothness of the mine boundary during the lateral blasting of the downward fan-shaped holes, reducing over-excavation and under-excavation of the mine, and reducing the disturbance of blasting vibration on both sides of the mine, so as to achieve the purpose of safe and efficient mining.

[0006] According to one aspect of the present application, a method for blasting a stope by combining pre-splitting blastholes with downward fan-shaped blastholes is provided, the method comprising:

[0007] The stopes to be mined are divided into one-step stopes and two-step stopes perpendicular to the direction of the ore body according to the mining sequence;

[0008] Construct the respective stope connecting roadways, drilling roadways, and ore-drawing roadways in the first-step stope and the second-step stope respectively, and use long cable bolts and bolt support systems to provide pre-support. Construct cutting crossheadings from the drilling roadway of the first-step stope and draw-in crossheadings from the ore-drawing roadway of the first-step stope;

[0009] Construct a first cutting raise connecting with the draw-in crossheading of the first-step stope in the cutting crossheading of the first-step stope, and use the first cutting raise as a free face and compensation space to blast the cutting crossheading of the first-step stope to form a first cutting slot, so as to provide a free face and compensation space for ore caving in the first-step stope through the first cutting slot;

[0010] Construct downward fan-shaped blast holes and presplitting blast holes in the drilling roadway of the first-step stope, and construct presplitting blast holes in the drilling roadway of the second-step stope;

[0011] Load explosives into the downward fan-shaped blast holes and each presplitting blast hole in the first-step stope, and blast each presplitting blast hole and the downward fan-shaped blast holes in the first-step stope in sequence;

[0012] Use the gas flowing through the ore-drawing roadway of the first-step stope to wash the first-step stope, so that the foul gas generated after washing flows into the stage roadway through the drilling roadway and stope connecting roadway of the first-step stope and is discharged. After removing the residual ore in the first-step stope, fill the first-step stope.

[0013] In an alternative embodiment, the length of the first-step stope is 20m - 40m, the width of the first-step stope is 12m - 20m, and the height of the first-step stope is the stage height; the length of the second-step stope is 20m - 40m, the width of the second-step stope is 12m - 18m, and the height of the second-step stope is the stage height.

[0014] In an alternative embodiment, construct the respective stope connecting roadways, drilling roadways, and ore-drawing roadways in the first-step stope and the second-step stope respectively, and use long cable bolts and bolt support systems to provide pre-support, including:

[0015] Construct an upper stope connecting roadway from the stage roadway to the first-step stope at the upper part of the stope. Arrange a drilling roadway along the stope stoping direction in the upper stope connecting roadway of the first-step stope, and use long cable bolts and bolt support systems to provide pre-support to maintain the stability of the upper stope connecting roadway and drilling roadway of the first-step stope. Among them, the drilling roadway of the first-step stope is arranged at the junction of the first-step stope and the second-step stope;

[0016] In the upper part of the stope, the upper stope connecting roadway is constructed from the stage roadway to the second-step stope. In the upper stope connecting roadway of the second-step stope, a drilling roadway is arranged along the stope extraction direction, and a long cable bolt and rock bolt support system is used to provide pre-support to maintain the stability of the upper stope connecting roadway and the drilling roadway of the second-step stope. Among them, the drilling roadway of the second-step stope is arranged at the junction of the first-step stope and the second-step stope, and the center line distance between the drilling roadway of the second-step stope and the drilling roadway of the first-step stope is the width of the first-step stope;

[0017] In the lower part of the stope, the lower stope connecting roadway is constructed from the stage roadway to the first-step stope. In the lower stope connecting roadway of the first-step stope, an ore-drawing roadway is arranged along the stope extraction direction, and a long cable bolt and rock bolt support system is used to provide pre-support to maintain the stability of the ore-drawing roadway of the first-step stope.

[0018] In an alternative embodiment, a first cut raise connected to the undercut crossheading of the first-step stope is constructed in the cut crossheading of the first-step stope, and the cut crossheading of the first-step stope is blasted to form a first cut slot with the first cut raise as the free face and compensation space, so as to provide a free face and compensation space for ore caving in the first-step stope, including:

[0019] Construct first downward parallel medium-length holes from the cut crossheading of the first-step stope, and use the medium-length hole blasting method to form a first cut raise based on the first downward parallel medium-length holes, so that the first cut raise is connected to the undercut crossheading of the first-step stope;

[0020] Second downward parallel medium-length holes are drilled in the cut crossheading of the first-step stope, and the first cut slot is formed by sectional sequential blasting based on the second downward parallel medium-length holes with the first cut raise as the free face and compensation space, so as to provide a free face and compensation space for ore caving in the first-step stope through the first cut slot.

[0021] In an alternative embodiment, downward fan-shaped blast holes and presplitting blast holes are constructed in the drilling roadway of the first-step stope, and presplitting blast holes are constructed in the drilling roadway of the second-step stope, including:

[0022] In the drilling roadway of the first-step stope, a rock drilling jumbo is used to construct downward fan-shaped blast holes and downward vertical holes as presplitting blast holes. Among them, the aperture of the downward fan-shaped blast holes is 165 mm, the row spacing is 3 m, the hole bottom distance is 3.5 m, the blast hole depth is 14 m to 52 m, the aperture of the presplitting blast holes in the first-step stope is 120 mm, the blast hole spacing is 1.2 m, and the blast hole depth is 46 m;

[0023] In the drilling roadway of the second-step stope, a drilling jumbo is used to construct downward vertical holes as pre-splitting blast holes. Among them, the aperture of the pre-splitting blast holes in the second-step stope is 120 mm, the hole spacing is 1.2 m, and the hole depth is 46 m.

[0024] In an alternative embodiment, explosives are loaded into the downward fan-shaped blast holes and each pre-splitting blast hole in the first-step stope, and each pre-splitting blast hole and the downward fan-shaped blast holes in the first-step stope are detonated in sequence, including:

[0025] Explosives are loaded into each pre-splitting blast hole using an axial continuous and radial decoupled charge structure, and each pre-splitting blast hole is detonated using the hole mouth forward initiation technique to form a pre-split crack;

[0026] Explosives are loaded into the downward fan-shaped blast holes in the first-step stope using a water column interval charge structure, and the downward fan-shaped blast holes in the first-step stope are detonated using the hole-by-hole delay and hole bottom reverse initiation techniques. Among them, the initiation time of the pre-splitting blast holes is 50 ms to 100 ms ahead of the initiation time of the downward fan-shaped blast holes.

[0027] In an alternative embodiment, the diameter of the explosives loaded into each pre-splitting blast hole is 45 mm, the blast hole delay time of each pre-splitting blast hole is 0 ms, and retreating mining is carried out from the cut groove to the stope end. According to the mining direction, 12 pre-splitting blast holes are detonated each time; the diameter of the explosives loaded into the downward fan-shaped blast holes in the first-step stope is 120 mm, the water column interval ratio is 30%, the blast hole delay time of the downward fan-shaped blast holes is 10 ms to 250 ms, and blasting is carried out in the V-shaped initiation sequence of first the middle and then both sides for the blast holes in the same row. Retreating mining is carried out from the cut groove to the stope end. According to the mining direction, two rows of blast holes are detonated each time.

[0028] In an alternative embodiment, after removing the residual ore in the first-step stope, the first-step stope is backfilled, including:

[0029] After removing the residual ore in the first-step stope, the steps of loading explosives into the downward fan-shaped blast holes and each pre-splitting blast hole in the first-step stope and detonating each pre-splitting blast hole and the downward fan-shaped blast holes in sequence are repeated until the first-step stope is completely mined, and then the first-step stope is backfilled.

[0030] In an alternative embodiment, after backfilling the first-step stope, the method further includes:

[0031] The second-step stope is mined and backfilled.

[0032] In an alternative embodiment, mining and backfilling the second-step stope includes:

[0033] In the lower part of the stope, the lower stope connecting roadway is constructed from the stage roadway to the second-step stope. The ore-drawing roadway is arranged along the stope mining direction in the lower stope connecting roadway of the second-step stope, and a long cable bolt and bolt support system is used to provide pre-support to maintain the stability of the ore-drawing roadway in the second-step stope;

[0034] The cutting crossheading is constructed from the drilling roadway in the second-step stope and the undercut crossheading is constructed from the ore-drawing roadway in the second-step stope;

[0035] The third downward parallel medium-length holes are constructed from the cutting crossheading in the second-step stope, and the second cutting raise is formed based on the third downward parallel medium-length holes by medium-length hole blasting method, so that the second cutting raise is connected to the undercut crossheading in the second-step stope;

[0036] The fourth downward parallel medium-length holes are drilled in the cutting crossheading in the second-step stope. Based on the second cutting raise as the free face and compensation space, the second cutting slot is formed by sectional sequential blasting based on the fourth downward parallel medium-length holes, so as to provide the free face and compensation space for the ore caving in the second-step stope through the second cutting slot;

[0037] The downward fan-shaped blast holes are constructed by using a rock drilling jumbo in the drilling roadway of the second-step stope. Among them, the diameter of the downward fan-shaped blast holes is 165 mm, the row spacing is 3 m, the hole bottom distance is 3.5 m, and the blast hole depth is 14 m to 52 m;

[0038] The explosive is loaded into the downward fan-shaped blast holes in the second-step stope by using the water column interval charging structure, and the downward fan-shaped blast holes in the second-step stope are blasted by using the hole-by-hole delay and hole bottom reverse initiation technology; among them, the diameter of the explosive loaded into the downward fan-shaped blast holes in the second-step stope is 120 mm, the water column interval ratio is 30%, the blast hole blasting delay time of the downward fan-shaped blast holes in the second-step stope is 10 ms to 250 ms, and the blasting is carried out according to the V-shaped initiation sequence of the middle first and then both sides in the same row of blast holes. Retreat mining is carried out from the cutting slot to the stope end. According to the mining direction, two rows of blast holes are blasted each time;

[0039] The second-step stope is cleaned by using the gas flowing through the ore-drawing roadway in the second-step stope, so that the dirty gas generated after cleaning is discharged into the stage roadway through the drilling roadway and the stope connecting roadway in the second-step stope. After removing the residual ore in the second-step stope, the steps of loading the explosive into the downward fan-shaped blast holes in the second-step stope and blasting the downward fan-shaped blast holes in the second-step stope in turn are repeated until the second-step stope is mined out, and then the second-step stope is backfilled.

[0040] With the above technical solution, a stope ore caving method using combined blasting of pre-splitting blast holes and downward fan-shaped blast holes provided by an embodiment of the present application is as follows. First, the ore body to be mined is divided into stopes in two steps according to the mining sequence, namely the first-step stope and the second-step stope, to ensure the orderly progress of mining operations. In the two stopes, stope crossheadings, drilling headings, and ore-drawing headings are respectively constructed, and a long cable bolt and rock bolt support system is used to provide necessary pre-support to enhance the stability and safety of the headings. In the drilling heading of the first-step stope, a cutting crossheading and a sill cutting crossheading are constructed, and a first cutting slot is formed by blasting, providing a necessary free face and compensation space for subsequent downward fan-shaped blast hole blasting. Downward fan-shaped blast holes and pre-splitting blast holes are constructed in the drilling heading of the first-step stope, while only pre-splitting blast holes are constructed in the drilling heading of the second-step stope. Explosives are loaded into the downward fan-shaped blast holes and each pre-splitting blast hole in the first-step stope, and blasting is carried out in sequence to achieve effective ore caving. After blasting, the stope is washed with the gas flowing through the ore-drawing heading to discharge the foul gas, and then the residual ore is removed, and the goaf is backfilled to prepare for subsequent mining operations. By introducing the combined blasting technology of pre-splitting blast holes and downward fan-shaped blast holes, the present application makes full use of the advantages of pre-splitting blasting and downward fan-shaped blasting without increasing additional development engineering, ensures the flatness of the stope boundary during the lateral blasting ore caving of the downward fan-shaped holes, reduces the overbreak and underbreak of the stope, and reduces the disturbance of blasting vibration to the two sides of the stope, so as to achieve the purpose of safe and efficient mining. At the same time, this solution also optimizes the mining process, improves the ore recovery rate and mining efficiency, and provides strong support for the safe and efficient mining of deep metal deposits.

[0041] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features, and advantages of the present application more obvious and understandable, the specific embodiments of the present application are specifically described below. Brief Description of the Drawings

[0042] The drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0043] Figure 1 A flow schematic diagram of a stope ore caving method using combined blasting of pre-splitting blast holes and downward fan-shaped blast holes provided by an embodiment of the present application is shown. Detailed Description of the Embodiments

[0044] The present application will be described in detail below with reference to the drawings and in combination with embodiments. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0045] In this embodiment, a stope ore caving method combining pre-splitting blast holes and downward fan-shaped blast holes is provided. As Figure 1 shown, the method includes:

[0046] Step 101: Divide the stope to be caved into a first-step stope and a second-step stope perpendicular to the ore body strike according to the mining sequence.

[0047] Optionally, the length of the first-step stope is 20 m to 40 m, the width of the first-step stope is 12 m to 20 m, and the height of the first-step stope is the stage height; the length of the second-step stope is 20 m to 40 m, the width of the second-step stope is 12 m to 18 m, and the height of the second-step stope is the stage height.

[0048] In the embodiment of the present application, in order to reasonably plan the mining sequence and ensure the orderly progress of mining operations. Dividing the stope into a first-step stope and a second-step stope can optimize the mining process according to the actual situation of the ore body and the mining conditions, reduce the mutual influence during the mining process, make the mining process more orderly, reduce the chaos and uncertainty during the mining process, and improve the mining efficiency.

[0049] Step 102: Construct the respective stope connecting roadways, drilling roadways, and ore-drawing roadways in the first-step stope and the second-step stope, and provide pre-support using a long cable bolt and rock bolt support system. Construct a cutting cross-heading from the drilling roadway of the first-step stope and a sill drift from the ore-drawing roadway of the first-step stope.

[0050] In the embodiment of the present application, in order to construct the roadway system required for mining and provide necessary support measures to ensure the safe progress of mining operations. The construction of the stope connecting roadways, drilling roadways, and ore-drawing roadways is the basis of mining operations, while the long cable bolt and rock bolt support system can provide a stable support effect and prevent the roof of the roadway from collapsing. Constructing the respective stope connecting roadways, drilling roadways, and ore-drawing roadways in the first-step stope and the second-step stope and providing pre-support using a long cable bolt and rock bolt support system improve the stability and safety of the roadway system, reduce the risk of roof collapse of the roadway, and ensure the safety of mining operations. In addition, construct a cutting cross-heading from the drilling roadway of the first-step stope and a sill drift from the ore-drawing roadway of the first-step stope for subsequent construction of a cutting slot in the first-step stope.

[0051] Step 103: Construct a first cutting raise connecting to the sill drift of the first-step stope in the cutting cross-heading of the first-step stope, and blast the cutting cross-heading of the first-step stope with the first cutting raise as the free face and compensation space to form a first cutting slot, so as to provide a free face and compensation space for ore caving in the first-step stope through the first cutting slot.

[0052] In the embodiment of the present application, in order to form a cutting slot in the first-stage stope to provide a free face and a compensation space for subsequent downward fan-shaped hole blasting. By constructing the first cutting raise in the first-stage stope and using it as a free face and a compensation space for blasting, the required cutting slot can be formed, providing the necessary free face and compensation space for downward fan-shaped hole blasting, improving the blasting effect, and reducing the overbreak and underbreak phenomenon.

[0053] Step 104: Construct downward fan-shaped holes and presplitting holes in the drilling roadway of the first-stage stope, and construct presplitting holes in the drilling roadway of the second-stage stope.

[0054] In the embodiment of the present application, downward fan-shaped holes and presplitting holes are arranged in the drilling roadway for subsequent blasting operations. The downward fan-shaped holes are used for the main ore caving operation, while the presplitting holes are used to control the blasting boundary, reduce the overbreak and underbreak phenomenon, and improve the flexibility and controllability of the blasting operation.

[0055] Step 105: Load explosives into the downward fan-shaped holes and each presplitting hole in the first-stage stope, and blast each presplitting hole and the downward fan-shaped holes in the first-stage stope in sequence.

[0056] In the embodiment of the present application, the ore caving operation is realized by blasting each presplitting hole and the downward fan-shaped holes in sequence. The blasting of the presplitting holes can control the blasting boundary, while the blasting of the downward fan-shaped holes is used for the main ore caving operation, realizing effective ore caving, and improving the safety and controllability of the blasting operation.

[0057] Step 106: Use the gas flowing through the ore-drawing roadway of the first-stage stope to wash the first-stage stope, so that the dirty gas generated after washing passes through the drilling roadway and the stope connecting roadway of the first-stage stope and converges into the stage roadway for discharge. After removing the residual ore in the first-stage stope, fill the first-stage stope.

[0058] In the embodiment of the present application, the dirty gas and residual ore in the stope are cleaned up and the filling operation is carried out to prepare for subsequent mining operations. By washing the stope, the dirty gas can be discharged, improving the working environment; removing the residual ore can improve the ore recovery rate; and filling can reduce the influence of the goaf on subsequent mining operations, providing good conditions for subsequent mining operations.

[0059] By applying the technical solution of this embodiment, first, the ore body to be mined is divided into stope for two steps according to the mining sequence, namely the first-step stope and the second-step stope, to ensure the orderly progress of mining operations. In the two stopes, stope crossheadings, drilling headings and ore-drawing headings are respectively constructed, and a long cable bolt and rock bolt support system is used to provide necessary pre-support to enhance the stability and safety of the headings. In the drilling heading of the first-step stope, a cutting crossheading and a undercut crossheading are constructed, and a first cutting slot is formed by blasting, providing a necessary free face and compensation space for subsequent downward fan-shaped hole blasting. Downward fan-shaped holes and pre-splitting holes are constructed in the drilling heading of the first-step stope, while only pre-splitting holes are constructed in the drilling heading of the second-step stope. Explosives are loaded into the downward fan-shaped holes and each pre-splitting hole in the first-step stope, and blasting is carried out in sequence to achieve effective ore caving. After blasting, the stope is washed with the gas flowing through the ore-drawing heading to discharge the foul gas, and then the residual ore is removed, and the goaf is backfilled to prepare for subsequent mining operations. By introducing the combined blasting technology of pre-splitting holes and downward fan-shaped holes, this application makes full use of the advantages of pre-splitting blasting and downward fan-shaped blasting without increasing additional development engineering, ensures the flatness of the stope boundary during the lateral blasting ore caving of the downward fan-shaped holes, reduces the overbreak and underbreak of the stope, and reduces the disturbance of blasting vibration to the two sides of the stope, so as to achieve the purpose of safe and efficient mining. At the same time, this solution also optimizes the mining process, improves the ore recovery rate and mining efficiency, and provides strong support for the safe and efficient mining of deep metal deposits.

[0060] In the embodiment of this application, optionally, the stope crossheadings, drilling headings and ore-drawing headings of the first-step stope and the second-step stope are respectively constructed, and a long cable bolt and rock bolt support system is used to provide pre-support, including:

[0061] The upper stope crossheading is constructed from the level heading to the first-step stope at the upper part of the stope. The drilling heading is arranged along the stope retreat direction in the upper stope crossheading of the first-step stope, and a long cable bolt and rock bolt support system is used to provide pre-support to maintain the stability of the upper stope crossheading and the drilling heading of the first-step stope, wherein the drilling heading of the first-step stope is arranged at the junction of the first-step stope and the second-step stope;

[0062] The upper stope crossheading is constructed from the level heading to the second-step stope at the upper part of the stope. The drilling heading is arranged along the stope retreat direction in the upper stope crossheading of the second-step stope, and a long cable bolt and rock bolt support system is used to provide pre-support to maintain the stability of the upper stope crossheading and the drilling heading of the second-step stope, wherein the drilling heading of the second-step stope is arranged at the junction of the first-step stope and the second-step stope, and the center line distance between the drilling heading of the second-step stope and the drilling heading of the first-step stope is the width of the first-step stope;

[0063] In the lower part of the stope, a lower stope connecting roadway is constructed from the stage roadway to the aforesaid first-step stope. An ore-drawing roadway is arranged along the stope stoping direction in the lower stope connecting roadway of the first-step stope, and a long cable bolt and rock bolt support system is adopted to provide pre-support so as to maintain the stability of the ore-drawing roadway of the first-step stope.

[0064] In this embodiment, in the upper part of the stope, an upper stope connecting roadway is constructed from the stage roadway to the first-step stope. Along the stope stoping direction, a drilling roadway is arranged below the upper stope connecting roadway. The drilling roadway is arranged at the junction of the first-step stope and the second-step stope, which is convenient for flexible drilling operations between the two stopes. The long cable bolt and rock bolt support system is adopted to pre-support the upper stope connecting roadway and the drilling roadway to ensure the stability and safety of the roadway. Similarly, in the upper part of the stope, an upper stope connecting roadway is constructed from the stage roadway to the second-step stope. Along the stope stoping direction, a drilling roadway is arranged below the upper stope connecting roadway. The drilling roadway is also arranged at the junction of the first-step stope and the second-step stope, and maintains a certain centerline distance (equal to the width of the first-step stope) from the drilling roadway of the first-step stope to avoid mutual interference. The long cable bolt and rock bolt support system is also adopted to provide pre-support. In the lower part of the stope, a lower stope connecting roadway is constructed from the stage roadway to the first-step stope. Along the stope stoping direction, an ore-drawing roadway is arranged below the lower stope connecting roadway. The ore-drawing roadway is used for the transportation and discharge of ore, and its stability and safety are crucial. The long cable bolt and rock bolt support system is also adopted to pre-support the lower stope connecting roadway and the ore-drawing roadway. By adopting the long cable bolt and rock bolt support system to pre-support the stope connecting roadway, the drilling roadway and the ore-drawing roadway in the embodiment of the present application, the stability and safety of the roadway can be significantly enhanced, which helps to reduce the risk of roof caving of the roadway and ensure the life safety and physical health of mining operation personnel. The drilling roadway is arranged at the junction of the first-step stope and the second-step stope, which is convenient for flexible drilling operations between the two stopes, helps to optimize the mining process and improve the mining efficiency.

[0065] In the embodiment of the present application, optionally, a first cutting raise connecting with the undercut crossheading of the first-step stope is constructed in the cutting crossheading of the first-step stope, and the cutting crossheading of the first-step stope is blasted to form a first cutting slot with the first cutting raise as the free face and compensation space, so as to provide the free face and compensation space for the ore caving of the first-step stope, including:

[0066] Construct first downward parallel medium-length holes from the cutting crossheading of the first-step stope, and form the first cutting raise based on the first downward parallel medium-length holes by medium-length hole blasting method, so that the first cutting raise is connected with the undercut crossheading of the first-step stope;

[0067] In the cut cross drift of the one-step stope, second downward parallel medium-deep holes are drilled. Using the first cut raise as the free face and compensation space, a first cut slot is formed by sectional sequential blasting based on the second downward parallel medium-deep holes, so as to provide a free face and compensation space for ore drawing in the one-step stope through the first cut slot.

[0068] In this embodiment, starting from the cut cross drift of the one-step stope, the first group of downward parallel medium-deep holes (referred to as the first downward parallel medium-deep holes) are constructed downward. The medium-deep hole blasting method is adopted, and blasting is carried out based on these medium-deep holes to form the first cut raise. This raise needs to be connected to the sill drift of the one-step stope to provide the necessary free face and compensation space for subsequent blasting operations. In the cut cross drift of the one-step stope, the second group of downward parallel medium-deep holes (referred to as the second downward parallel medium-deep holes) are drilled. Using the already formed first cut raise as the free face and compensation space, sectional sequential blasting is carried out based on the second downward parallel medium-deep holes, that is, the blasting will be carried out in stages according to a predetermined order to ensure that the formation of the cut slot meets the design requirements. Through this series of blasting operations, a first cut slot is finally formed in the cut cross drift. This cut slot will provide the necessary free face and compensation space for the ore drawing operation in the one-step stope, which helps to optimize the blasting effect and reduce the phenomenon of overbreak and underbreak. In the embodiment of the present application, by precisely designing and constructing the downward parallel medium-deep holes and using the first cut raise as the free face and compensation space for sectional sequential blasting, the blasting effect can be improved, providing favorable conditions for subsequent ore drawing operations. Using the cut slot as the free face and compensation space for blasting can more effectively control the blasting boundary, which helps to reduce overbreak and underbreak phenomena and improve the ore recovery rate and mining efficiency.

[0069] In the embodiment of the present application, optionally, downward fan-shaped blast holes and presplitting blast holes are constructed in the drilling drift of the one-step stope, and presplitting blast holes are constructed in the drilling drift of the two-step stope, including: using a rock drill in the drilling drift of the one-step stope to construct downward fan-shaped blast holes and downward vertical holes as presplitting blast holes. Among them, the aperture of the downward fan-shaped blast holes is 165 mm, the row spacing is 3 m, the hole bottom distance is 3.5 m, and the blast hole depth is 14 m to 52 m. The aperture of the presplitting blast holes in the one-step stope is 120 mm, the blast hole spacing is 1.2 m, and the blast hole depth is 46 m; using a rock drill in the drilling drift of the two-step stope to construct downward vertical holes as presplitting blast holes. Among them, the aperture of the presplitting blast holes in the two-step stope is 120 mm, the blast hole spacing is 1.2 m, and the blast hole depth is 46 m.

[0070] In this embodiment, for a one-step stope, in its drilling roadway, a drilling jumbo is used for construction. The construction content includes downward fan-shaped blast holes and downward vertical holes (used as pre-splitting blast holes). The specific parameters of the downward fan-shaped blast holes are as follows: hole diameter 165 mm, row spacing 3 m, hole bottom distance 3.5 m, and blast hole depth ranging from 14 m to 52 m. The parameters of the pre-splitting blast holes (downward vertical holes) are: hole diameter 120 mm, blast hole spacing 1.2 m, and blast hole depth 46 m. For a two-step stope, in its drilling roadway, the drilling jumbo is also used for construction. The construction content is downward vertical holes, which are used as pre-splitting blast holes. The specific parameters of the pre-splitting blast holes are: hole diameter 120 mm, blast hole spacing 1.2 m, and blast hole depth 46 m. Such a construction method ensures that in stopes of different steps, the arrangement of blast holes can meet the mining requirements, while ensuring the safety and efficiency of construction. By precisely controlling the hole diameter, spacing, and depth of the blast holes, the blasting range and effect can be effectively controlled, thus achieving the expected mining goal.

[0071] In an embodiment of the present application, optionally, explosives are loaded into the downward fan-shaped blast holes and each pre-splitting blast hole in the one-step stope, and each pre-splitting blast hole and the downward fan-shaped blast hole in the one-step stope are detonated in sequence, including: loading explosives into each pre-splitting blast hole using an axial continuous and radial decoupled charge structure, detonating each pre-splitting blast hole using the hole mouth forward initiation technique to form a pre-splitting crack; loading explosives into the downward fan-shaped blast holes in the one-step stope using a water column interval charge structure, and detonating the downward fan-shaped blast holes in the one-step stope using the hole-by-hole delay and hole bottom reverse initiation technique, wherein the initiation time of the pre-splitting blast hole is 50 ms to 100 ms ahead of the initiation time of the downward fan-shaped blast hole.

[0072] In this embodiment, an axially continuous and radially decoupled charge structure is adopted to load explosives into each pre-splitting blast hole. This charge structure helps to form a more flat pre-splitting crack during blasting and reduce the damage to the surrounding rock mass. The orifice forward initiation technique is used to blast each pre-splitting blast hole. Orifice forward initiation means that the initiating charge package is located at the orifice of the blast hole, which helps to ensure that the blasting wave can propagate uniformly along the axial direction of the blast hole, thus forming a continuous pre-splitting crack. The initiation time of the pre-splitting blast hole needs to be ahead of that of the downward fan-shaped blast hole, and the specific leading time is 50 ms to 100 ms. Such a time difference can ensure that the pre-splitting crack has been formed before the blasting of the downward fan-shaped blast hole, thus providing a necessary free face and compensation space for the blasting of the downward fan-shaped blast hole, which helps to control the blasting range and optimize the blasting effect. A water column interval charge structure is adopted to load explosives into the downward fan-shaped blast holes in the first-step stope. The water column interval charge structure helps to reduce the shock wave and vibration effects during blasting and improve the energy utilization rate of the explosives. The downward fan-shaped blast holes are blasted by using the hole-by-hole delay and bottom reverse initiation techniques. Hole-by-hole delay initiation means that there is a certain interval in the initiation time of each blast hole, which helps to control the propagation direction and range of the blasting wave and reduce the phenomena of over-excavation and under-excavation. Bottom reverse initiation means that the initiating charge package is located at the bottom of the blast hole, which helps to ensure that the blasting wave can more effectively break the rock mass. The blasting of the downward fan-shaped blast holes needs to be carried out in a predetermined order to ensure that the blasting wave can propagate uniformly and orderly, so as to achieve the expected mining effect.

[0073] In the embodiment of the present application, optionally, the diameter of the explosives loaded into each pre-splitting blast hole is 45 mm, the blast hole blasting delay time of each pre-splitting blast hole is 0 ms, and retreating from the cutting groove to the end of the stope, according to the mining direction, 12 pre-splitting blast holes are initiated each time; the diameter of the explosives loaded into the downward fan-shaped blast holes in the first-step stope is 120 mm, the water column interval ratio is 30%, the blast hole blasting delay time of the downward fan-shaped blast holes is 10 ms to 250 ms, and the blasting is carried out in a V-shaped initiation order with the middle hole first and the two side holes later in the same row of blast holes. Retreating from the cutting groove to the end of the stope, according to the mining direction, two rows of blast holes are blasted each time.

[0074] In this embodiment, the diameter of the explosive loaded in each pre-splitting blast hole is 45 mm, ensuring that the explosive can effectively explode in the blast hole while reducing excessive damage to the blast hole wall. The blast hole blasting delay time of each pre-splitting blast hole is 0 ms, and all the pre-splitting blast holes for each blast will be detonated simultaneously. Since the main purpose of the pre-splitting blast holes is to form smooth cracks in the rock mass, simultaneous detonation can ensure the continuity and flatness of the cracks. Mining retreats from the cut groove towards the end of the stope. According to the mining direction, 12 pre-splitting blast holes are detonated each time. Such a detonation sequence and quantity selection are to ensure that during the mining process, the cracks in the rock mass can expand in the predetermined direction while reducing unnecessary damage to the surrounding rock mass. The diameter of the explosive loaded in the downward fan-shaped blast holes of the one-step stope is 120 mm, and the water column interval ratio is 30%. The larger diameter of the explosive can provide stronger explosive force, while the water column interval helps to reduce the damage of the explosion shock wave to the blast hole wall and improve the energy utilization rate of the explosive. The blast hole blasting delay time of the downward fan-shaped blast holes is 10 ms to 250 ms. The delay time within this range can ensure that the blast waves between the blast holes do not interfere with each other, thus optimizing the blasting effect. Blasting is carried out in a V-shaped detonation sequence where the blast holes in the same row are detonated from the middle to both sides first. Such a detonation sequence can ensure that during the blasting process, the fragmentation of the rock mass can proceed more evenly and orderly, reducing overbreak and underbreak phenomena. Mining retreats from the cut groove towards the end of the stope. According to the mining direction, two rows of blast holes are detonated each time. Such a selection of the detonation quantity can, while ensuring the blasting effect, reduce unnecessary damage to the surrounding rock mass and help control the mining progress.

[0075] In an embodiment of the present application, optionally, after removing the residual ore in the one-step stope, filling the one-step stope includes: after removing the residual ore in the one-step stope, repeating the steps of loading explosives in the downward fan-shaped blast holes and each pre-splitting blast hole in the one-step stope, and sequentially detonating each pre-splitting blast hole and the downward fan-shaped blast holes until the one-step stope is mined out, and then filling the one-step stope.

[0076] In this embodiment, during the stoping process of the first-stage stope, as the ore is gradually mined, some residual ore will be left. These residual ores need to be removed by appropriate means to prepare for the subsequent filling work. The methods for removing residual ores may include mechanical excavation and other methods, and the specific selection depends on factors such as the nature of the ore, mining conditions, and cost-effectiveness. After removing the residual ores, it is necessary to repeat the process of loading explosives into the downward fan-shaped blast holes and each presplitting blast hole in the first-stage stope and then carry out blasting in sequence. The purpose of this step is to ensure that the ore in the stope is completely mined and at the same time form necessary blasting cracks to facilitate the subsequent filling work. When the ore in the first-stage stope is completely mined and the formed blasting cracks meet the requirements, the filling work can be carried out to support and manage the goaf, control the caving of surrounding rock and surface subsidence, and create safe and convenient conditions for the subsequent mining work. This process in the embodiment of the present application realizes the effective mining and filling management of the first-stage stope by precisely controlling steps such as charging, blasting, and filling. Such a process helps to optimize the mining effect, improve the ore recovery rate, and at the same time reduce the damage to the surrounding rock mass and mining costs.

[0077] In an embodiment of the present application, optionally, after backfilling the first-step stope, the method further includes: mining and backfilling the second-step stope. Specifically: constructing a lower stope connecting roadway from the stage roadway to the second-step stope at the lower part of the stope, arranging an ore-drawing roadway along the ore-drawing direction of the stope in the lower stope connecting roadway of the second-step stope, and using a long cable bolt and bolt support system to provide pre-support to maintain the stability of the ore-drawing roadway of the second-step stope; constructing a cutting cross-heading from the drilling roadway of the second-step stope and a bottom-drawing cross-heading from the ore-drawing roadway of the second-step stope; constructing third downward parallel medium-length holes from the cutting cross-heading of the second-step stope, and forming a second cutting raise by medium-length hole blasting based on the third downward parallel medium-length holes, so that the second cutting raise is connected to the bottom-drawing cross-heading of the second-step stope; drilling fourth downward parallel medium-length holes in the cutting cross-heading of the second-step stope, and forming a second cutting slot by sectional sequential blasting based on the fourth downward parallel medium-length holes with the second cutting raise as the free face and compensation space, so as to provide a free face and compensation space for ore caving in the second-step stope through the second cutting slot; using a rock drilling jumbo to construct downward fan-shaped blast holes in the drilling roadway of the second-step stope, wherein the diameter of the downward fan-shaped blast holes is 165 mm, the row spacing is 3 m, the hole bottom distance is 3.5 m, and the blast hole depth is 14 m to 52 m; loading explosives into the downward fan-shaped blast holes in the second-step stope by using a water column interval charging structure, and blasting the downward fan-shaped blast holes in the second-step stope by using the hole-by-hole delay and hole bottom reverse initiation technology; wherein, the diameter of the explosives loaded into the downward fan-shaped blast holes in the second-step stope is 120 mm, the water column interval ratio is 30%, the blast hole blasting delay time of the downward fan-shaped blast holes in the second-step stope is 10 ms to 250 ms, blasting is carried out in the V-shaped initiation sequence of first the middle and then both sides of the same row of blast holes, retreating mining from the cutting slot to the end of the stope, and blasting two rows of blast holes each time according to the ore-drawing direction; cleaning the second-step stope by using the gas flowing through the ore-drawing roadway of the second-step stope, so that the dirty gas generated after cleaning flows into the stage roadway through the drilling roadway and the stope connecting roadway of the second-step stope and is discharged, after removing the residual ore in the second-step stope, repeating the steps of loading explosives into the downward fan-shaped blast holes in the second-step stope and blasting the downward fan-shaped blast holes in the second-step stope in sequence until the second-step stope is mined out, and backfilling the second-step stope.

[0078] In this embodiment, regarding the stoping and filling process of the two-step stope, it specifically includes: constructing the lower stope connecting roadway from the stage roadway to the two-step stope at the lower part of the stope to provide a passage for subsequent ore-drawing roadway layout and mining work. Ore-drawing roadways are arranged along the stoping direction of the stope in the lower stope connecting roadway of the two-step stope. A long cable bolt and bolt support system is used to provide pre-support to maintain the stability of the ore-drawing roadway in the two-step stope and ensure safety during the mining process. The cutting crossheading is constructed from the drilling roadway in the two-step stope to provide a basis for subsequent medium-deep hole blasting and the formation of the cutting slot. The undercut crossheading is constructed from the ore-drawing roadway in the two-step stope to facilitate subsequent mining work. The third downward parallel medium-deep holes are constructed from the cutting crossheading in the two-step stope, and the second cutting raise is formed based on the third downward parallel medium-deep holes using the medium-deep hole blasting method, so that the second cutting raise is connected to the undercut crossheading in the two-step stope. The fourth downward parallel medium-deep holes are drilled in the cutting crossheading in the two-step stope. With the second cutting raise as the free face and compensation space, the second cutting slot is formed by sectional sequential blasting based on the fourth downward parallel medium-deep holes. The second cutting slot provides a free face and compensation space for ore caving in the two-step stope to ensure that the ore can collapse smoothly during the mining process. Downward fan-shaped blast holes are constructed using a rock drill in the drilling roadway in the two-step stope. The diameter of the downward fan-shaped blast holes is 165 mm, the row spacing is 3 m, the hole bottom distance is 3.5 m, and the blast hole depth is 14 m to 52 m. Explosives are loaded into the downward fan-shaped blast holes in the two-step stope using a water column interval charging structure. The diameter of the explosives is 120 mm, and the water column interval ratio is 30%. The blast hole blasting delay time is 10 ms to 250 ms, and blasting is carried out according to the V-shaped initiation sequence of blasting the middle hole first and then the two side holes in the same row. Stoping is carried out from the cutting slot towards the end of the stope. According to the stoping direction, two rows of blast holes are blasted each time. The two-step stope is washed using the gas flowing through the ore-drawing roadway in the two-step stope. The dirty gas generated after washing is discharged into the stage roadway through the drilling roadway and the stope connecting roadway in the two-step stope, and the residual ore in the two-step stope is removed to prepare for subsequent stoping and filling work. The steps of reloading explosives into the downward fan-shaped blast holes in the two-step stope and sequentially blasting the downward fan-shaped blast holes in the two-step stope are repeated until the two-step stope is completely stoped, and then the two-step stope is filled. In summary, this process in the embodiment of the present application realizes effective stoping and filling management of the two-step stope by precisely controlling steps such as stope preparation, construction of cutting crossheading and undercut crossheading, formation of cutting raise and cutting slot, construction and blasting of downward fan-shaped blast holes, stope washing and removal of residual ore, and repeated charging and blasting. Such a process helps to optimize the mining effect, improve the ore recovery rate, and at the same time reduce the damage to the surrounding rock mass and the mining cost.

[0079] The beneficial effects of using a stope ore caving method with combined blasting of pre-splitting blast holes and downward fan-shaped blast holes provided by the embodiment of the present application are as follows:

[0080] (1) Reduce overbreak and underbreak in the stope, and solve the problem of difficult control of the stope boundary in downward fan-shaped blast hole blasting. The pre-splitting blast holes can pre-form a relatively flat fracture surface, making the stope boundary relatively flat after the downward fan-shaped blast hole blasting.

[0081] (2) Reduce blasting vibration and lower the damage to surrounding rock. The pre-splitting blast holes are blasted first to form a pre-crack, which can serve as a barrier to reduce the impact of seismic waves generated during the subsequent downward fan-shaped blast hole blasting on the surrounding environment and lower the damage to the surrounding rock.

[0082] (3) Improve the blasting quality. The formation of the pre-crack can reduce the clamping effect of the surrounding rock during blasting, isolate the propagation of the blasting energy of the downward fan-shaped holes, make the rock mass fragments after the downward fan-shaped blast hole blasting more uniform, reduce the large block rate, improve the crushing degree of the ore, and is conducive to subsequent loading and transportation.

[0083] In summary, the combined blasting ore drawing technology of pre-splitting blast holes and downward fan-shaped blast holes has obvious advantages in improving the blasting effect, reducing overbreak and underbreak in the stope, reducing the mining and cutting cost, reducing blasting vibration, and ground pressure prevention and control. It is an advanced and worthy of popularizing blasting ore drawing technology in the deep metal mine mining.

[0084] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0085] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method for blasting a mine in a stope by combining pre-splitting blastholes with downward fan-shaped blastholes, characterized in that: The method comprises: The stopes to be mined are divided into one-step stopes and two-step stopes perpendicular to the direction of the ore body according to the mining sequence; The respective mine connection tunnels, rock drilling tunnels and mining tunnels are constructed in the first-step mine and the second-step mine respectively, and long anchor cables and anchor support systems are used to provide pre-support, and cross tunnels are cut from the rock drilling tunnel of the first-step mine, and bottom cross tunnels are constructed from the mining tunnel of the first-step mine, including: constructing an upper mine connection tunnel from the stage tunnel to the first-step mine at the upper part of the mine, arranging rock drilling tunnels in the upper mine connection tunnel of the first-step mine along the mining direction of the mine, and using long anchor cables and anchor support systems to provide pre-support to maintain the stability of the upper mine connection tunnel and rock drilling tunnel of the first-step mine, wherein the rock drilling tunnel of the first-step mine is arranged at the junction of the first-step mine and the second-step mine; constructing a rock drilling tunnel from the stage tunnel to the second-step mine at the upper part of the mine The upper stope joint tunnel is constructed, a rock drilling tunnel is arranged in the upper stope joint tunnel of the two-step stope along the stope recovery direction, and a long anchor cable and an anchor support system are used to provide pre-support to maintain the stability of the upper stope joint tunnel and the rock drilling tunnel of the two-step stope, wherein the rock drilling tunnel of the two-step stope is arranged at the junction of the one-step stope and the two-step stope, and the centerline distance between the rock drilling tunnel of the two-step stope and the rock drilling tunnel of the one-step stope is the width of the one-step stope; the lower stope joint tunnel is constructed from the stage tunnel to the one-step stope at the lower part of the stope, a mine exit tunnel is arranged in the lower stope joint tunnel of the one-step stope along the stope recovery direction, and a long anchor cable and an anchor support system are used to provide pre-support to maintain the stability of the mine exit tunnel of the one-step stope; Constructing a first cutting rise in the cutting cross tunnel of the first-step stope, which is connected with the bottom cross tunnel of the first-step stope, and blasting the cutting cross tunnel of the first-step stope with the first cutting rise as a free surface and compensation space to form a first cutting groove, so as to provide a free surface and compensation space for the ore falling in the first-step stope through the first cutting groove; Constructing downward fan-shaped blastholes and pre-splitting blastholes in the rock drilling tunnel of the first-step stope, and constructing pre-splitting blastholes in the rock drilling tunnel of the second-step stope; The method comprises: charging explosives into the downward fan-shaped blastholes and each pre-splitting blasthole of the first-step stope, and sequentially blasting each pre-splitting blasthole and the downward fan-shaped blasthole of the first-step stope, comprising: charging explosives into each pre-splitting blasthole by adopting an axially continuous radially uncoupled charge structure, and blasting each pre-splitting blasthole by adopting a hole mouth forward detonation technique to form pre-cracks; charging explosives into the downward fan-shaped blastholes of the first-step stope by adopting a water column interval charge structure, and blasting the downward fan-shaped blastholes of the first-step stope by adopting a hole-by-hole delay and a hole bottom reverse detonation technique, wherein the detonation time of the pre-splitting blastholes is 50ms to 100ms ahead of the detonation time of the downward fan-shaped blastholes; The first-step mine is cleaned by utilizing the gas flowing through the mining tunnel of the first-step mine, so that the dirty gas generated after cleaning is discharged through the rock drilling tunnel and the mine connecting tunnel of the first-step mine and the merging stage tunnel, and the first-step mine is filled after removing the residual ore in the first-step mine.

2. The method for blasting a stope using a combination of pre-splitting blastholes and downward fan-shaped blastholes according to claim 1, characterized in that: The length of the first-step mining area is 20m~40m, the width of the first-step mining area is 12m~20m, and the height of the first-step mining area is the stage height; the length of the second-step mining area is 20m~40m, the width of the second-step mining area is 12m~18m, and the height of the second-step mining area is the stage height.

3. The method for blasting a stope using a combination of pre-splitting blastholes and downward fan-shaped blastholes according to claim 1, characterized in that: A first cutting rise connected with the bottom pull-out lane of the first-step stope is constructed in the cutting lane of the first-step stope, and the cutting lane of the first-step stope is blasted to form a first cutting groove with the first cutting rise as a free surface and compensation space, so as to provide a free surface and compensation space for the ore falling in the first-step stope through the first cutting groove, including: Constructing a first downward parallel medium-long hole from the cutting horizontal roadway of the first-step stope, and forming a first cutting rise based on the first downward parallel medium-long hole by using a medium-long hole blasting method, so that the first cutting rise is connected with the bottom pulling horizontal roadway of the first-step stope; A second downward parallel medium-depth hole is excavated in the cutting horizontal tunnel of the first-step mining area, and a first cutting groove is formed by segmented sequential blasting based on the second downward parallel medium-depth hole with the first cutting shaft as the free surface and compensation space, so as to provide a free surface and compensation space for ore dropping in the first-step mining area through the first cutting groove.

4. The method for blasting a stope using a combination of pre-splitting blastholes and downward fan-shaped blastholes according to claim 1, characterized in that: Constructing downward fan-shaped blastholes and pre-splitting blastholes in the rock drilling tunnel of the first-step stope, and constructing pre-splitting blastholes in the rock drilling tunnel of the second-step stope, including: In the rock drilling tunnel of the first-step stope, a rock drilling vehicle is used to construct downward fan-shaped blastholes and downward vertical holes as pre-splitting blastholes, wherein the diameter of the downward fan-shaped blastholes is 165 mm, the row spacing is 3 m, the hole bottom distance is 3.5 m, and the blasthole depth is 14 m to 52 m; the diameter of the pre-splitting blastholes in the first-step stope is 120 mm, the blasthole spacing is 1.2 m, and the blasthole depth is 46 m; A rock drilling vehicle is used to construct downward vertical holes as pre-splitting blastholes in the rock drilling tunnel of the second-step stope, wherein the pre-splitting blastholes of the second-step stope have a hole diameter of 120 mm, a blasthole spacing of 1.2 m, and a blasthole depth of 46 m.

5. The method for blasting a stope using a combination of pre-splitting blastholes and downward fan-shaped blastholes according to claim 1, characterized in that: The diameter of the explosive loaded in each pre-splitting blasthole is 45mm, the blasting delay time of each pre-splitting blasthole is 0ms, and mining is withdrawn from the cutting groove to the end of the mining field. According to the mining direction, 12 pre-splitting blastholes are detonated each time; the diameter of the explosive loaded in the downward fan-shaped blastholes of the mining field in the first step is 120mm, the water column spacing ratio is 30%, the blasting delay time of the downward fan-shaped blastholes is 10ms~250ms, and blasting is carried out in a V-shaped detonation order of the middle and then the two sides of the same row of blastholes, and mining is withdrawn from the cutting groove to the end of the mining field. According to the mining direction, two rows of blastholes are blasted each time.

6. The method for blasting a stope using a combination of pre-splitting blastholes and downward fan-shaped blastholes according to claim 5, characterized in that: After removing the residual ore in the first-step stope, the first-step stope is filled, comprising: After removing the residual ore in the first-step mining area, repeat the steps of loading explosives into the downward fan-shaped blastholes and each pre-splitting blasthole in the first-step mining area, and blasting each pre-splitting blasthole and the downward fan-shaped blasthole in sequence until the first-step mining area is mined and the first-step mining area is filled.

7. The method for blasting a stope using a combination of pre-splitting blastholes and downward fan-shaped blastholes according to any one of claims 1 to 6, characterized in that: After filling the stope in the first step, the method further comprises: The two-step stope is mined and filled.

8. The method for blasting a stope using a combination of pre-splitting blastholes and downward fan-shaped blastholes according to claim 7, characterized in that: The two-step stope is mined and filled, including: Constructing a lower stope joint tunnel from the stage tunnel to the second-step stope at the lower part of the stope, arranging a mine exit tunnel along the stope recovery direction in the lower stope joint tunnel of the second-step stope, and using a long anchor cable and bolt support system to provide pre-support to maintain the stability of the mine exit tunnel of the second-step stope; Construction of a cutting cross tunnel from the rock drilling tunnel of the second-step stope and construction of a bottom cross tunnel from the mining tunnel of the second-step stope; Constructing a third downward parallel medium-long hole from the cutting horizontal roadway of the second-step stope, and forming a second cutting rise based on the third downward parallel medium-long hole by using a medium-long hole blasting method, so that the second cutting rise is connected to the bottom pulling horizontal roadway of the second-step stope; A fourth downward parallel medium-length hole is excavated in the cutting horizontal tunnel of the two-step stope, and a second cutting groove is formed by segmented sequential blasting based on the fourth downward parallel medium-length hole with the second cutting rise as a free surface and compensation space, so as to provide a free surface and compensation space for ore dropping in the two-step stope through the second cutting groove; A rock drilling vehicle is used to construct downward fan-shaped blast holes in the rock drilling tunnel of the second-step stope, wherein the diameter of the downward fan-shaped blast holes is 165 mm, the row spacing is 3 m, the hole bottom distance is 3.5 m, and the blast hole depth is 14 m to 52 m; The downward fan-shaped blastholes of the two-step stope are charged with explosives by adopting a water column interval charging structure, and the downward fan-shaped blastholes of the two-step stope are blasted by adopting hole-by-hole delay and bottom-of-hole reverse detonation technology; wherein the diameter of the explosives charged in the downward fan-shaped blastholes of the two-step stope is 120 mm, the water column interval ratio is 30%, the blasting delay time of the downward fan-shaped blastholes of the two-step stope is 10 ms to 250 ms, and the blasting is carried out in a V-shaped detonation sequence of the middle and then the two sides of the same row of blastholes, and the mining is withdrawn from the cutting groove to the end of the stope, and two rows of blastholes are blasted each time according to the mining direction; The second-step mine is cleaned by utilizing the gas flowing through the mine exit tunnel of the second-step mine, so that the dirty gas generated after cleaning is discharged through the rock drilling tunnel and the mine connecting tunnel of the second-step mine and the merging stage tunnel. After removing the residual ore in the second-step mine, the steps of loading explosives in the downward fan-shaped blast holes of the second-step mine and blasting the downward fan-shaped blast holes of the second-step mine in sequence are repeated until the second-step mine is mined and the second-step mine is filled.

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