Method for detecting material level in blast hole

Abstract

The invention discloses a method for detecting the material level in a blast hole, and relates to the field of blasting filler, and the method comprises the following steps: obtaining the material target filling depth of a target blast hole at the current material injection stage; the winding roll is unwound, so that the material level switch descends to a target measurement position corresponding to the target filling depth of the material; judging whether the filling material reaches the target measurement position or not; if the filling material does not reach the target measurement position, material injection and detection are continued; if the filling material reaches the target measurement position, judging whether a next material injection stage exists or not; if the next material injection stage exists, the material target filling depth of the next material injection stage of the target blast hole is updated to be the material target filling depth of the current material injection stage, the steps are repeated, and if the next material injection stage does not exist, material injection filling knots of the target blast hole are determined. According to the method provided by the invention, the real-time detection performance of material level measurement of the filler is high, and automatic filling of the blast hole of the strip mine field is realized.

Description

Technical Field

[0001] The invention relates to the field of blasting fillers, and in particular to a method for detecting material levels in blastholes. Background Art

[0002] In the process of open-pit blasting, charging operation is an indispensable part. Granular explosives are filled into the blast hole to complete the charging operation, and then the hole is sealed before blasting.

[0003] Currently, when the aperture of blastholes in open-pit mines is small, conventional non-contact level measuring instruments such as ultrasonic level meters or radar level meters are prone to inadvertent contact of sound waves or electromagnetic waves with the hole wall during testing, resulting in inaccurate material level measurement, making it difficult to meet the requirements for material level detection in blastholes with small apertures. Open-pit mine blastholes are dusty when materials are filled, and measurement methods based on laser and machine vision are easily interfered by dust, basically unable to meet the material level measurement needs in open-pit mines. Conventional contact level measuring instruments such as rotary paddle level meters or hammer level meters have been found to have long single test times when testing the material level in blastholes, resulting in low test efficiency and difficulty meeting the rapid construction needs of open-pit mines. Traditional manual blasthole measurement methods also have the disadvantages of large human measurement errors and repeatability errors, and the measurement is time-consuming, making them unsuitable for large-scale industrial production. In short, the existing technology cannot effectively detect and control the filling depth of granular explosives according to the actual situation on site, resulting in that when granular explosives are loaded into the blasthole, the granular explosives in the blasthole cannot be loaded to the specified depth, and it is easy for the granular explosives to be loaded too much or too little. If the amount of granular explosives loaded is large, it is easy to cause waste of explosives and uncontrollable explosion accidents; if the amount of granular explosives loaded is small, it is not conducive to the blasting work.

[0004] Therefore, in response to the above problems, it is necessary to propose a method for detecting the material level in the blasthole for explosive filling in the blasthole of the open-pit mine, so as to effectively detect the depth of the explosive filling, thereby solving or at least partially solving the above technical problems. Summary of the Invention

[0005] The method for detecting the material level in a blasthole provided by the present invention solves the technical problem that it is difficult to effectively detect the filling depth of explosives in a blasthole in existing open-pit mines.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows: A method for detecting a material level in a blasthole is used in a material level detection system in a blasthole. The material level detection system in the blasthole includes a material conveying pipeline, a force wheel frame, and a material level detection mechanism. The material conveying pipeline includes a plug-in material guide filling pipe and a material introduction and guide pipe obliquely arranged on the plug-in material guide filling pipe. The plug-in material guide filling pipe is arranged vertically. The force wheel frame is fixedly sleeved on the plug-in material guide filling pipe and is located below the material introduction and guide pipe. The material level detection mechanism includes a winding drum, a retractable cable, and a material level switch. The connecting end of the retractable cable is wound on the winding drum. The free end of the retractable cable is connected to the material level switch. The material level switch is arranged from the top of the plug-in material guide filling pipe through the plug-in material guide filling pipe. The method for detecting the material level in the blasthole comprises the following steps: S10, obtaining the target filling depth of the material in the current injection stage of the target blasthole; S20, unwinding the reel to lower the material level switch to the target measurement position corresponding to the target filling depth of the material; S30, delivering filling material into the target blasthole through the material delivery pipeline, and performing real-time material level inspection using a material level switch to determine whether the filling material has reached the target measurement position; S41, if the filling material does not reach the target measurement position, continue filling and testing; S42, if the filling material reaches the target measurement position, determine whether there is a next filling stage; S431, if there is a next injection stage, then the target material filling depth of the next injection stage of the target blasthole is updated to the target material filling depth of the current injection stage, and the process proceeds to steps S10 to S42; S432: If there is no next injection stage, the injection filling of the target blasthole is completed.

[0007] Furthermore, in step S30, determining whether the filling material reaches the target measurement position specifically includes the following steps: S31, determining whether a material level in place signal sent by a material level switch is received. If the filling material wraps around the material level switch, the material level switch sends a material level in place signal; S321, if the material level is in place signal is received, the reel is unwound to lower the material level switch by a preset length; S322, if the material level in place signal is not received, continue detecting until the material level in place signal is detected; S33, after a preset time interval, the winding reel causes the material level switch to rise by a preset length, and at the same time, obtains the winding tension value when the material level switch rises; S34, if the winding tension value is not less than the effective tension threshold, it is determined that the filling material reaches the target measurement position; S35: If the winding tension value is less than the effective tension threshold, proceed to step S31.

[0008] Furthermore, in step S30, before the filling material is transported into the target blasthole through the material transport pipeline, the following steps are further included: The mixed explosive of ammonium nitrate and diesel is transported into the material conveying pipeline according to the designed ratio, wherein the diesel ratio of the mixed explosive injected into the deeper hole is not less than the diesel ratio of the mixed explosive injected into the shallower hole.

[0009] Furthermore, the servo motor drives the cable reel to rotate around the central axis to reel in or unreel the cable, and one rotation of the cable reel is divided into P pulses corresponding to the servo motor, where P is a positive integer greater than 100. Using the formula Calculate the length of the unwinding cable when unwinding the nth turn, where: is the diameter of the cable ring corresponding to the kth unwinding circle; Using the formula Calculate the redundant length of the cable from the nth circle to the n+1th circle, where: is the diameter of the cable ring corresponding to the k+1th turn of unwinding; Determine the length of the suspension cable based on the arrangement elevation of the cable drum relative to the horizontal plane of the blasthole; The layout depth corresponding to the target measurement position is calculated using the formula: total hole depth minus the unwinding cable length and the cable redundant length.

[0010] Furthermore, the material level switch adopts a capacitive material level detection switch.

[0011] The present invention has the following beneficial effects: The method for detecting the material level in a blasthole provided by the present invention performs real-time material level detection during filling by hanging a material level switch in the blasthole to the current material target filling depth. The method adopts a contact material level measurement method. Compared with non-contact level measuring instruments such as ultrasonic material level meters or radar material level meters, and laser and machine vision measuring instruments, the method has higher reliability and more accurate detection results. At the same time, when the filling material reaches the current material target filling depth, the method automatically obtains the next current material target filling depth of the target blasthole, updates the next current material target filling depth to the current material target filling depth, and then fills the material in the next section, thereby realizing automated filling of blastholes in open-pit mines.

[0012] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings: Figure 1 1 is a schematic structural diagram of a blasthole material level detection system in a specific embodiment of the present invention; Figure 2 1 is a flow chart of a method for detecting material level in a blasthole in a specific embodiment of the present invention; Figure 3 yes Figure 2 A schematic diagram of a specific process for determining whether the filling material has reached the target measurement position.

[0014] Legend: 100. Material level detection system in the blasthole; 10. Material conveying pipeline; 20. Force-applying wheel frame; 30. Material level detection mechanism; 31. Cable reel; 32. Cable retracting and releasing; 33. Material level switch. DETAILED DESCRIPTION

[0015] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0017] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0018] In addition, the descriptions of "first", "second", etc. in the present invention are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0019] Please refer to Figure 1 and Figure 2 As shown, the present invention provides a method for detecting the material level in a blasthole, which is used in a material level detection system 100 in a blasthole. The material level detection system 100 in a blasthole includes a material conveying pipeline 10, a force wheel frame 20 and a material level detection mechanism 30. The material conveying pipeline 10 includes a jack material guide filling pipe and a material introduction and guide pipe obliquely arranged on the jack material guide filling pipe, the jack material guide filling pipe is arranged vertically, the force wheel frame 20 is fixedly sleeved on the jack material guide filling pipe and is located below the material introduction and guide pipe, the material level detection mechanism 30 includes a winding drum 31, a retractable cable 32 and a material level switch 33, the connecting end of the retractable cable 32 is wound on the winding drum 31, the free degree of the retractable cable 32 is connected to the material level switch 33, and the material level switch 33 is arranged from the top of the jack material guide filling pipe through the jack material guide filling pipe; The method for detecting the material level in the blasthole comprises the following steps: S10, obtaining the target filling depth of the material in the current injection stage of the target blasthole; S20, unwinding the wire reel to lower the material level switch to a target measurement position corresponding to the target filling depth of the material; S30, delivering filling material into the target blasthole through the material delivery pipeline, and performing real-time material level inspection using a material level switch to determine whether the filling material has reached the target measurement position; S41, if the filling material does not reach the target measurement position, continue filling and testing; S42, if the filling material reaches the target measurement position, determining whether there is a next filling stage; S431, if there is a next injection stage, then the target material filling depth of the next injection stage of the target blasthole is updated to the target material filling depth of the current injection stage, and the process proceeds to steps S10 to S42; S432: If there is no next injection stage, the injection filling of the target blasthole is completed.

[0020] The method for detecting the material level in a blasthole provided by the present invention performs real-time material level detection during filling by hanging a material level switch in the blasthole to the current material target filling depth. The method adopts a contact material level measurement method. Compared with non-contact level measuring instruments such as ultrasonic material level meters or radar material level meters, and laser and machine vision measuring instruments, the method has higher reliability and more accurate detection results. At the same time, when the filling material reaches the current material target filling depth, the method automatically obtains the next current material target filling depth of the target blasthole, updates the next current material target filling depth to the current material target filling depth, and then fills the material in the next section, thereby realizing automated filling of blastholes in open-pit mines.

[0021] It can be understood that when injecting material into the target blasthole, it can be divided into multiple working sections for step-by-step injection and filling, and the target filling depth of the material is calculated based on the bottom of the target blasthole.

[0022] Please refer to Figure 3 Furthermore, in step S30, determining whether the filling material reaches the target measurement position specifically includes the following steps: S31, determining whether a material level in place signal sent by the material level switch is received. If the filling material wraps the material level switch, the material level switch sends the material level in place signal. S321, if the material level signal is received, unwinding the wire reel to lower the material level switch by a preset length; S322, if the material level in place signal is not received, continue detecting until the material level in place signal is detected; S33, reeling the wire reel after a preset time interval to raise the material level switch by a preset length, and simultaneously obtaining a reeling tension value when the material level switch is raised; S34, if the winding tension value is not less than the effective tension threshold, determining that the filling material reaches the target measurement position; S35: If the winding tension value is less than the effective tension threshold, proceed to step S31.

[0023] It is understandable that in the solution of the present invention, the preset time interval is set according to actual conditions, and can be 1 second, or other time intervals such as 2 seconds or 5 seconds, and the effective tension threshold is set according to actual conditions.

[0024] Furthermore, in step S30, before the filling material is transported into the target blasthole through the material transport pipeline, the following steps are further included: The mixed explosive of ammonium nitrate and diesel is transported into the material conveying pipeline according to the designed ratio, wherein the diesel ratio of the mixed explosive injected into the deeper hole is not less than the diesel ratio of the mixed explosive injected into the shallower hole.

[0025] Furthermore, the servo motor drives the winding drum to rotate around the central axis to reel in or unreel the retractable cable, and one rotation of the winding drum is divided into P pulses corresponding to the servo motor, where P is a positive integer greater than 100; Using the formula Calculate the length of the unwinding cable when unwinding the nth turn, where: is the diameter of the cable ring corresponding to the kth unwinding circle; Using the formula Calculate the redundant length of the cable from the nth circle to the n+1th circle, where: is the diameter of the cable ring corresponding to the k+1th turn of unwinding; Determining the length of the suspension cable according to the arrangement elevation of the cable drum relative to the horizontal plane of the blasthole; The layout depth corresponding to the target measurement position is calculated using the formula: total hole depth minus the unwinding cable length and the cable redundant length.

[0026] In one embodiment of the present invention, one turn of the cable reel is divided into 10,000 pulse steps corresponding to the servo motor, and the winding method is to stack the turns one by one. The diameter of the innermost turn is 90 mm, and the outer diameter of the tensile cable (retractable cable) is 3.5 mm. If the total number of wound coils is m, the corresponding cable coil diameter when unwinding the kth turn is for mm.

[0027] Furthermore, the material level switch utilizes a capacitive level detection switch. In the present invention, the controller of the capacitive level detection switch detects the presence of material by measuring changes in capacitance caused by changes in the dielectric constant of the air in the material box. To detect these subtle changes, the sensor utilizes a detection circuit capable of operating at a relatively low frequency (6kHz). The capacitive detection principle is well-suited for detecting material levels within blastholes, as it overcomes unfavorable factors such as high dust levels and high airflow speeds within the blasthole. Specifically, if the filler material envelops the level switch, the switch emits a material level in-place signal.

[0028] In the solution of the present invention, a capacitive level detection switch is used, which is more suitable for detecting the material level in the blasthole than the electrode detection switch. Among them, the electrode detection switch uses the electrical conductivity of the material to measure the high and low liquid levels, and can also be used for liquids and wet solids with weak conductivity. Since the material in the blasthole is a dry solid with low electrical conductivity, the electrode measurement principle is not suitable for detecting the material level in the blasthole.

[0029] In the solution of the present invention, a paddle-rotor type material level inspection and detection switch is used. Compared with the paddle-rotor type detection switch, it is more suitable for detecting the material level in the blasthole. The paddle-rotor type blade is connected to the clutch by a transmission shaft. When it does not contact the material, the motor maintains normal operation. When the blade contacts the material and causes resistance, the motor will stop rotating, and the electrical output will simultaneously output a contact signal to measure the material level height. An indicator light can also be connected to display the status. Since the paddle-rotor type requires the paddle-rotor blade to keep rotating, and the material conveying speed and conveying airflow in the blasthole are relatively fast, the paddle-rotor blade may malfunction without sufficient contact with the material. Therefore, the measurement principle of the paddle-rotor type is also not suitable for detecting the material level in the blasthole.

[0030] In the solution of the present invention, a capacitive material level detection switch is used. Compared with a tuning fork detection switch, it is more suitable for detecting the material level in the blasthole. Among them, the tuning fork detection switch is designed by utilizing the damping effect of the medium on the tuning fork vibration and the principle of piezoelectric effect. The sensing part for detecting the material level is composed of a tuning fork, which itself has a fixed vibration frequency and amplitude. When the tuning fork is damped by the medium, the tuning fork stops vibrating, and the control circuit drives the relay to send a switching signal. Due to the vibration and amplitude generated by the material in the blasthole hitting the tuning fork in the high-speed airflow, the tuning fork detection principle is also not suitable for detecting the material level in the blasthole.

[0031] The present invention utilizes a capacitive level detection switch, which is more suitable for detecting material levels within blastholes than photoelectric detection switches. When the sensor tip of a photoelectric detection switch is in air, infrared light from the sensor tip is reflected back to a transistor detector. When the sensor tip is in liquid, the infrared light is refracted from the sensor tip, reducing the energy reaching the detector and enabling level detection. However, the large amount of dust within a blasthole significantly reduces the energy reaching the detector, making the photoelectric detection principle unsuitable for detecting material within blastholes.

[0032] In the solution of the present invention, a capacitive material level detection switch is used, which is more suitable for detecting the material level in the blast hole than the ultrasonic detection switch. The ultrasonic detection switch measures the horizontal position by calculating the duration and intensity of the high-frequency sound waves reflected back to the sensor from the liquid surface - the time required is relative to the distance between the sensor and the liquid. Similar to the analysis of the ultrasonic principle under the penetrating type, the ultrasonic detection principle under the non-contact type is also not suitable for material detection in the blast hole.

[0033] The present invention employs a capacitive level detection switch, which is more suitable for detecting material levels within blastholes than laser-based detection switches. A semiconductor laser emits a continuous or high-speed pulsed laser beam, which reflects off the surface of the object being measured and is then received by a laser receiver. The time difference between laser emission and laser reception is accurately recorded, thereby determining the distance from the laser radar to the object being measured. However, the high dust content within the blasthole significantly reduces the pulsed laser beam reflected from the material surface back to the laser receiver, leading to significant laser measurement errors. Similarly, the laser detection principle is not suitable for detecting material within blastholes.

[0034] In the solution of the present invention, a capacitive material level detection switch is used, which is more suitable for detecting the material level in the blasthole than a radar detection switch. The radar detection switch uses the principle of echo ranging. Its horn-shaped or rod-shaped antenna transmits microwaves to the surface of the material to be measured. When the microwaves propagate to the surface of materials with different relative dielectric constants, they are reflected and received by the antenna. The time difference between the transmitted wave and the received wave is proportional to the distance between the material surface and the antenna. The distance can be determined by measuring the propagation time. Due to the large amount of dust in the blasthole, the echo energy reflected from the material surface back to the radar antenna will be greatly reduced, resulting in large radar measurement errors. Similarly, the radar detection principle is not suitable for material detection in blastholes.

[0035] The present invention utilizes a capacitive level detection switch, which is more suitable for detecting material levels within blastholes than microwave-based detection switches. In microwave-based detection switches, if microwave-absorbing material is present in the same plane as the receiver, the microwave beam will not reach the receiver, and thus the receiver will not detect the microwave beam. When the receiver detects the microwave beam, a state change triggers a relay. However, the high dust content within the blasthole prevents the microwave beam from reaching the receiver, ultimately leading to large microwave measurement errors. Similarly, the microwave detection principle is not suitable for detecting material within blastholes.

[0036] It is understood that in the specific implementation of the blasthole material level detection method of the present invention, the system must first set the target measurement position for the target blasthole material level (target material filling depth) based on actual conditions. The servo motor then drives the cable reel to drive the reel-in and reel-out cable to move the material level switch to the specified target measurement position and issue a material level measurement ready feedback signal. The control system automatically sets the rotational speed of the three discharge valves at the bottom of the material tank in advance based on the set target measurement position. The larger the hole depth, the higher the discharge valve rotational speed is set, while the smaller the hole depth, the lower the discharge valve rotational speed is set. The hole depth setting can also affect the ratio of ammonium nitrate to diesel. When the hole depth is set higher, the system increases the speed of the diesel plunger pump, resulting in a greater proportion of diesel in the material and ultimately a greater explosive energy. When the hole depth is set smaller, the system decreases the speed of the diesel plunger pump, resulting in a smaller proportion of diesel in the material and ultimately a lower explosive energy. It is understood that in the scheme of the present invention, the depth of the injection hole is inversely proportional to the injection time.

[0037] In the solution of the present invention, a pneumatic conveying system is used to transport materials and fill target blastholes. When the pneumatic conveying system receives the material level measurement ready feedback signal, it starts to transport materials to the target blasthole through the material conveying pipeline. After the material reaches the material level switch position and completely wraps the probe of the material level switch, the material level switch will automatically send a material level in place signal to the system; after the system receives the material level in place signal sent by the material level switch, the system automatically controls the servo motor to move downward for a small displacement and delays to detect whether the tension exerted on the servo motor reaches the set effective tension threshold. If the effective tension threshold is reached, it is accurately judged that the material level switch is indeed surrounded by material. If the effective tension threshold is not reached, the system will continue to add material until the material level in place signal is received and the effective tension threshold received by the servo motor reaches the set effective tension threshold. The system will then send a material level measurement completion signal. After receiving the material level measurement completion signal, the system automatically drives the reel and the reel-and-reel cable through the servo motor to quickly pull the material level switch back to a position near the reel to prepare for the next material level measurement.

[0038] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for detecting material level in a blasthole, characterized in that: Used for a material level detection system in a blasthole, the material level detection system in the blasthole includes a material conveying pipeline, a force wheel frame and a material level detection mechanism, the material conveying pipeline includes a jack material guide filling pipe and a material introduction and guide pipe obliquely arranged on the jack material guide filling pipe, the jack material guide filling pipe is arranged vertically, the force wheel frame is fixedly sleeved on the jack material guide filling pipe and is located below the material introduction and guide pipe, the material level detection mechanism includes a winding drum, a retractable cable and a material level switch, the connecting end of the retractable cable is wound on the winding drum, the free degree of the retractable cable is connected to the material level switch, and the material level switch is arranged from the top of the jack material guide filling pipe through the jack material guide filling pipe; The method for detecting the material level in the blasthole comprises the following steps: S10, obtaining the target filling depth of the material in the current injection stage of the target blasthole; S20, unwinding the wire reel to lower the material level switch to a target measurement position corresponding to the target filling depth of the material; S30, delivering filling material into the target blasthole through the material delivery pipeline, and performing real-time material level inspection using a material level switch to determine whether the filling material has reached the target measurement position; S41, if the filling material does not reach the target measurement position, continue filling and testing; S42, if the filling material reaches the target measurement position, determining whether there is a next filling stage; S431, if there is a next injection stage, then the target material filling depth of the next injection stage of the target blasthole is updated to the target material filling depth of the current injection stage, and the process proceeds to steps S10 to S42; S432: If there is no next injection stage, the injection filling of the target blasthole is completed.

2. The method for detecting material level in a blasthole according to claim 1, wherein: In step S30, determining whether the filling material has reached the target measurement position specifically includes the following steps: S31, determining whether a material level in place signal sent by the material level switch is received. If the filling material wraps the material level switch, the material level switch sends the material level in place signal. S321, if the material level signal is received, unwinding the wire reel to lower the material level switch by a preset length; S322, if the material level in place signal is not received, continue detecting until the material level in place signal is detected; S33, reeling the wire reel after a preset time interval to raise the material level switch by a preset length, and simultaneously obtaining a reeling tension value when the material level switch is raised; S34, if the winding tension value is not less than the effective tension threshold, determining that the filling material reaches the target measurement position; S35: If the winding tension value is less than the effective tension threshold, proceed to step S31.

3. The method for detecting material level in a blasthole according to claim 1, wherein: In step S30, before the filling material is transported into the target blasthole through the material transport pipeline, the following steps are also included: The mixed explosive of ammonium nitrate and diesel is transported into the material conveying pipeline according to the designed ratio, wherein the diesel ratio of the mixed explosive injected into the deeper hole is not less than the diesel ratio of the mixed explosive injected into the shallower hole.

4. The method for detecting material level in a blasthole according to any one of claims 1 to 3, characterized in that: The servo motor drives the winding drum to rotate around the central axis to reel in or unreel the retractable cable, and one rotation of the winding drum is divided into P pulses corresponding to the servo motor, where P is a positive integer greater than 100; Using the formula Calculate the length of the unwinding cable when unwinding the nth turn, where: is the diameter of the cable ring corresponding to the kth unwinding circle; Using the formula Calculate the redundant length of the cable from the nth circle to the n+1th circle, where: is the diameter of the cable ring corresponding to the k+1th turn of unwinding; Determining the length of the suspension cable according to the arrangement elevation of the cable drum relative to the horizontal plane of the blasthole; The layout depth corresponding to the target measurement position is calculated using the formula: total hole depth minus the unwinding cable length and the cable redundant length.

5. The method for detecting material level in a blasthole according to any one of claims 1 to 3, characterized in that: The material level switch adopts a capacitive material level detection switch.

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