Deep-sea mining plume diffusion in-situ monitoring system and monitoring method thereof

Abstract

The invention provides a deep-sea mining plume diffusion in-situ monitoring system and a monitoring method thereof, the deep-sea mining plume diffusion in-situ monitoring system comprises a monitoring center node device and a portable monitoring node device, and mining plume diffusion in-situ monitoring can be carried out through a monitoring network. According to the method, in-situ monitoring of the plume of the sediment can be achieved, the method has important significance on mining environment influence evaluation, an in-situ means for effectively positioning three-dimensional space distribution of the plume is filled up, and the requirement for monitoring the deposition thickness of plume particles is met. The plume influence environment element change relation is constructed, and the blank of plume environment influence total element monitoring is filled. The establishment of the relationship between plume diffusion and environmental element change is beneficial to the quantitative evaluation of the mining environment influence. The system can monitor and analyze the physical and chemical process, biological diversity influence and the like of the surrounding environment of mining activities, observation data can provide effective real parameters for plume numerical simulation, data support can be provided for environmental parameter prediction and benthic organism class group influence prediction, and three-dimensional space distribution of plumes can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of seabed exploration and marine engineering geology, and in particular to an in-situ monitoring system and a monitoring method for deep-sea mining plume diffusion. Background Art

[0002] The different stages of deep-seabed resource development will have an impact on the marine environment. Mining vehicles remove solid minerals from the seabed, and giant benthic organisms will be directly affected by the mining vehicle operations; the stirred-up sediment particles spread with the bottom current to form plumes, and the particles adhere to the surface of large organisms, blocking their respiratory systems, and toxic substances such as heavy metals have a toxic effect on aquatic organisms; the fragile chemical environment at the interface between sediments and water bodies is disrupted, and interstitial water characterized by ionic states mixes with near-bottom water and spreads widely, which has a long-term impact on the function of the seabed ecosystem. In addition, light pollution and noise pollution will be generated during long-term mining operations. A large amount of waste generated during the processing of seabed minerals is discarded in the ocean, and a large number of pollutants generated by ships engaged in the transportation industry during transportation are directly discharged into the sea, which will cause pollution to the deep-sea environment. Since deep-sea resources are usually located in areas with complex geological structures and significant and concentrated fault activities, deep-sea mining is likely to induce earthquakes and cause geological disasters such as submarine landslides in the later stages. These links in the exploitation of deep-sea resources will have an impact on the deep-sea ecosystem. If deep-sea mineral resources are to be mined commercially, the environmental impact of deep-sea mining must be evaluated. Plume diffusion environmental monitoring is currently an important means of evaluating the degree of mining environmental impact.

[0003] At present, the commercial-scale mining system has not yet been finalized, and the intensity of its environmental disturbance cannot be judged. The extent of the environmental impact of commercial-scale mining is still unclear. There is a lack of research on the redeposition and diffusion of deep-sea plumes and their impact on the deep-sea bottom environment and biological groups. The severity and spatial scale of plumes formed by deep-sea mining are still controversial, and the response mechanism of plume disturbance redeposition is still unclear. At present, the in-situ monitoring methods for deep-sea mining plumes have incomplete and inaccurate assessment parameters, and it is impossible to conduct in-situ monitoring of the diffusion of seabed mining plumes for a long time. A technical method system for monitoring and evaluating the environmental impact of deep-sea mining has not yet been established, and it is impossible to provide technical and data support for the environmental impact assessment of commercial mining. There is an urgent need for an in-situ monitoring system for the diffusion of deep-sea mining plumes. Summary of the invention

[0004] In order to make up for the shortcomings of the prior art, the present invention provides an in-situ monitoring system and a monitoring method for deep-sea mining plume diffusion. The monitoring system includes a monitoring central node device and a portable monitoring node device, which can perform in-situ monitoring of mining plume diffusion through monitoring networking.

[0005] The present invention is implemented by the following technical solutions: an in-situ monitoring system for deep-sea mining plume diffusion, comprising a central monitoring node device, three type I portable monitoring node devices, three type II portable monitoring node devices, and a sea surface monitoring buoy; The central monitoring node device includes an instrument frame, which is divided into three parts: upper, middle and lower. The center position of the upper frame of the instrument frame is connected to one end of the first Kevlar cable, and the other end of the first Kevlar cable is connected to the deployment and recovery pressure-resistant buoy. The upper frame of the instrument frame is surrounded by a floating material installed on the outside, and the top of the floating material is installed with an acoustic releaser, an Iridium beacon, an optical beacon and an acoustic communication machine. Four groups of first seabed pressure-resistant buoys are installed at the four corners of the upper frame of the instrument frame. The main control cabin, dissolved oxygen sensor, binocular camera control cabin, and CTD sensor are placed clockwise inside the upper frame of the instrument frame. The plume particle monitoring device, plume environment image monitoring device and plume redeposition thickness monitoring device are installed clockwise on the bottom periphery of the upper frame of the instrument frame; four groups of seawater dissolved oxygen batteries are placed in the middle frame of the instrument frame, and the bottom frame of the instrument frame is composed of four supporting legs, and the bottom counterweight trays are installed at the bottom through the counterweight unhooking device; The type I portable monitoring node device includes a recovery beacon and a sediment trap, which are connected by a second Kevlar cable, four second glass floats are installed inside the recovery beacon, a second acoustic communication device is installed at the bottom of the recovery beacon, three plume three-dimensional diffusion monitoring systems are equidistantly installed on the second Kevlar cable, a sediment trap battery compartment is installed at the bottom of the sediment trap, the plume three-dimensional diffusion monitoring system includes a sensor outer compartment and a watertight plug connected to one end thereof, a circuit board and a collector are installed inside the sensor outer compartment, a wiring electrode is installed inside the watertight plug, the wiring electrode is a platinum electrode evenly distributed at four positions, the ratio electrode and the natural potential electrode are both made of titanium alloy-graphene material, the redox electrode is a platinum electrode, and each sub-node is collected sequentially by an AD acquisition to realize electrical parameter collection; The type II portable monitoring node device includes a third glass float and a node device frame, the third glass float and the node device frame are connected by a third Kevlar cable, a fourth pressure-resistant float is installed on the upper part of the node device frame, and a third acoustic communicator, an electrochemical sensor and a type II monitoring node control cabin are installed inside the node device frame; As a preferred solution, the plume redeposition thickness monitoring device includes a rotating motor cabin and an optical measurement cabin.

[0006] As a preferred solution, the plume environment image monitoring device includes a lighting unit and a binocular camera.

[0007] As a preferred embodiment, the plume electrochemical sensor includes a sensor housing, wherein an electrical sensor connector and an electrochemical sensor data connector are respectively installed at the left and right ends of the sensor housing, and an electrochemical sensor electrode, an electrochemical sensor circuit board and an electrochemical sensor data collector are installed inside the sensor housing, the electrochemical sensor electrode is electrically connected to the electrical sensor connector, and the electrochemical sensor data connector is electrically connected to the electrochemical sensor data collector.

[0008] A monitoring method for an in-situ monitoring system of deep-sea mining plume diffusion, characterized in that it specifically comprises the following steps: Step S1, platform deployment: the central monitoring node device is deployed through the ship-machine cable and arranged 50 m away from the mining vehicle in the actual mining operation area; Step S2, determining the flow direction: determining the plume flow direction according to the travel distance of the mining vehicle; Step S3, node deployment: First, deploy the central monitoring node device around the mining vehicle, deploy the type I portable monitoring node device on the back of the mining vehicle plume, and then deploy the type I portable monitoring node device and the type II portable monitoring node device every 1 km on both sides of the mining vehicle to cover the plume deployment range; the steps for deploying and recovering the central monitoring node device are as follows: Step S3-1, lowering with cable: using the geological compass of the mother ship to go down, hooking the cable with the help of the acoustic releaser, and then lowering the base, and then unhooking the acoustic releaser; Step S3-2, the equipment is powered by seawater dissolved oxygen batteries, and the lithium battery of the equipment itself is used as a backup for the plume particle monitoring system, plume redeposition thickness monitoring system, plume environment image monitoring device, and plume biochemical environment monitoring device carried by the central monitoring node to work continuously and uninterruptedly, collect and store data at any time, and perform wireless transmission; Step S4, network observation, according to the direction of travel and working model of the mining vehicle, the central monitoring node device, the type I portable monitoring node device, and the type II portable monitoring node device continue to perform network monitoring, gather data for general control, and transmit data through acoustics; Step S5: Data analysis: According to the analysis of the uploaded data, the plume three-dimensional diffusion in-situ monitoring sensor carried by the Type I portable monitoring node device uses natural potential, redox potential, and resistivity to jointly invert turbidity; The inversion formula is: Where ρ is the resistivity (Ω·m), S is the salinity (‰), T is the temperature (K), s is the type of suspended particles, and c is the concentration of suspended particles in seawater (g·L -1 ), k(S,T,s) is used to determine salinity S, temperature T, and plume particle type.x , the rate of change of resistivity ρ with plume concentration c. SP is the natural potential value (mV), S is the salinity, T is the temperature (K), x is the type of plume particles, Z is the water level height relative to the reference electrode (cm), and c is the concentration of suspended particles in seawater (g·L -1 ). Eh is the redox potential (mV), S is the salinity (‰), T is the temperature (K), x is the type of plume particles, pH is the acidity and alkalinity of the solution, and DO is the dissolved oxygen content of the solution (mg·L -1 ), c is the concentration of suspended particles in seawater (g·L -1 )、 j (S,T,s,pH,DO) is used to determine salinity S, temperature T, plume particle type x , solution pH, solution dissolved oxygen content DO, the redox potential Eh changes with plume concentration c The rate of change.

[0009] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art: 1. The present invention is an in-situ monitoring system for the diffusion of seabed mining plumes. The central monitoring node uses seawater dissolved oxygen batteries and self-contained energy storage batteries to supply energy. It can monitor sediment plumes in situ (high-resolution monitoring of particles in plumes, three-dimensional diffusion monitoring of plumes, and monitoring of plume redeposition thickness and sedimentation volume. It is of great significance to the environmental impact assessment of mining, fills the in-situ means of effectively locating the three-dimensional spatial distribution of plumes, and can meet the needs of monitoring the deposition thickness of plume particles. Compared with the existing technology, it is more comprehensive and has a higher resolution.

[0010] 2. The present invention is an in-situ monitoring method for the environmental impact of plumes, which can construct the relationship between the changes in environmental factors affecting the plume, filling the gap in the monitoring of all factors of the plume environmental impact. Changes in environmental factors are a direct manifestation of the environmental impact of sediment plumes. The migration and diffusion of sediment plumes will change parameters such as water temperature, salinity, Eh, pH, and Do. Establishing the relationship between plume diffusion and changes in environmental factors is helpful for the quantitative evaluation of mining environmental impacts. The present invention involves sensors that can collect long-term in-situ observation data to meet the needs of long-term in-situ observations in the deep sea.

[0011] 3. The present invention is reasonably designed. It relies on the monitoring center node device and the portable monitoring node device, and the deployment and recovery method is simple and effective. It realizes comprehensive and systematic in-situ monitoring and environmental impact assessment of mining environmental impacts. It can monitor and analyze the physical and chemical processes and biodiversity impacts of the environment around mining activities. The observation data can provide effective real parameters for the numerical simulation of plumes, provide data support for the prediction of environmental parameters and the impact on benthic biological groups, and obtain the three-dimensional spatial distribution of plumes.

[0012] Additional aspects and advantages of the present invention will become apparent from the following description or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 This is the overall structure diagram of the central monitoring node device; Figure 2 This is the internal structure diagram of the central monitoring node device; Figure 3 Cross-sectional view of the central monitoring node device platform Figure 4 This is a schematic diagram of a Type I portable monitoring node device; Figure 5 Schematic diagram of the in-situ monitoring sensor for plume three-dimensional diffusion; Figure 6 This is a schematic cross-sectional diagram of the sensor for in-situ monitoring of plume three-dimensional diffusion; Figure 7 This is a schematic diagram of a type II portable monitoring node device; Figure 8 is a schematic cross-sectional view of an electrochemical sensor; Fig. 9 This is a schematic diagram of the deployment of central monitoring nodes; Fig.10 This is a working mode diagram of the deep-sea mining plume in-situ monitoring system; in, Figures 1 to 10 The corresponding relationship between the mark and the component is: 1- First Kevlar cable, 2- First seabed pressure-resistant buoy, 3- Acoustic releaser, 4- Floating material, 5- Instrument frame, 6- Plume sediment thickness monitoring device, 7- Plume environment image monitoring device, 8- Seawater dissolved oxygen battery, 9- Counterweight unhooking device, 10- First bottom counterweight tray, 11- Iridium beacon, 12- Optical beacon, 13- Acoustic communication machine, 14- Plume particle monitoring device, 15- Main control cabin, 16- Dissolved oxygen sensor, 17- Binocular camera control cabin, 18- CTD sensor, 19- Recovery beacon, 20- Second seabed pressure-resistant buoy, 21- Second acoustic communication machine, 22- Second Kevlar cable, 23- Plume three-dimensional diffusion monitoring device, 24-sediment trap, 25-sediment trap battery compartment, 26-second bottom unhooking counterweight tray, 27-watertight plug, 28-sensor outer compartment, 29-wiring channel, 30-circuit board, 31-collector, 32-third pressure-resistant float, 33-third Kevlar cable, 34-fourth pressure-resistant float, 35-third acoustic communicator, 36-electrochemical sensor, 37-Type II monitoring node control compartment, 38-electrical sensor connector, 39-sensor housing, 40-electrochemical sensor electrode, 41-electrochemical sensor circuit board, 42-electrochemical sensor data collector, 43-electrochemical sensor data connector, 44-deployment and recovery of pressure-resistant float. DETAILED DESCRIPTION

[0014] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0015] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0016] Combine the following Figures 1 to 10 The deep-sea mining plume diffusion in-situ monitoring system and monitoring method thereof according to the embodiment of the present invention are specifically described.

[0017] like Figures 1 to 7 As shown, the present invention proposes an in-situ monitoring system for deep-sea mining plume diffusion, which is characterized by comprising a central monitoring node device, three type I portable monitoring node devices, three type II portable monitoring node devices, and a sea surface monitoring buoy; the type I and type II monitoring nodes are arranged in a hexagon around the central monitoring node, and the sea surface monitoring buoy is connected on the sea surface; like Figure 1As shown, the core monitoring node device includes an instrument frame 5, which is divided into three parts: upper, middle and lower. The center position of the upper frame of the instrument frame 5 is connected to one end of the first Kevlar cable 1, and the other end of the first Kevlar cable 1 is connected to the deployment and recovery pressure-resistant buoy 44. The upper frame of the instrument frame 5 is surrounded by a floating material 4 installed on the outside, and the top of the floating material 4 is installed with an acoustic releaser 3, an Iridium beacon 11, an optical beacon 12 and an acoustic communication device 13. Four groups of first seabed pressure-resistant buoys 2 are installed at the four corners of the upper frame of the instrument frame 5. The main control cabin 15 is placed clockwise inside the upper frame of the instrument frame 5. , dissolved oxygen sensor 16, binocular camera control cabin 17, CTD sensor 18, the bottom periphery of the upper frame of the instrument frame 5 is clockwise installed with plume particle monitoring device 14, plume environment image monitoring device 7 and plume redeposition thickness monitoring device 6; four groups of seawater dissolved oxygen batteries 8 are placed in the middle frame of the instrument frame 5. The seawater dissolved oxygen battery 8 is composed of carbon fiber as the positive electrode material and magnesium alloy rod as the negative electrode material. The positive and negative electrodes react to generate electricity. The system requires a total of 8 single-module batteries, which are connected in parallel to the energy storage battery. The monitoring platform equipment is powered by the discharge of the energy storage battery. The bottom frame of the instrument frame 5 is four supporting legs and the bottom counterweight tray 10 is installed at the bottom through the counterweight unhooking device 9; the plume redeposition thickness monitoring device 6 includes a rotating motor cabin and an optical measurement cabin. The plume environment image monitoring device 7 includes a lighting unit and a binocular camera. Each device in the central monitoring node device is hollowed out and not airtight in a clockwise direction. Each device has pressure-resistant seabed working conditions, and the equipment is intensively arranged and space is used rationally. It can carry a variety of equipment, and the instruments and equipment do not interfere with each other and cooperate with each other.

[0018] like Figure 4 As shown, the type I portable monitoring node device includes a recovery beacon 19 and a sediment trap 24, which are connected by a second Kevlar cable 22, four second glass floats 20 are installed inside the recovery beacon 19, a second acoustic communicator 21 is installed at the bottom of the recovery beacon 19, three plume three-dimensional diffusion monitoring systems 23 are equidistantly installed on the second Kevlar cable 22, and a sediment trap battery compartment 25 is installed at the bottom of the sediment trap 24.

[0019] like Figure 5 , as shown in FIG6 , the plume three-dimensional diffusion monitoring system 23 includes a sensor outer compartment 28 and a watertight plug 27 connected to one end thereof, a circuit board 30 and a collector 31 are installed inside the sensor outer compartment 28, and a wiring electrode 29 is installed inside the watertight plug 27. The wiring electrode 29 is a platinum electrode evenly distributed at four positions, the ratio electrode and the natural potential electrode are both made of titanium alloy-graphene material, the redox electrode is a platinum electrode, and each sub-node is collected by an AD acquisition to realize the sequential collection of electrical parameters; The electrical turbidity inversion technology involved in the plume three-dimensional diffusion monitoring device has been well verified by the electrical-turbidity inversion model constructed by artificial neural network technology. The plume three-dimensional diffusion monitoring system has a monitoring range of 30m and a resolution of 1m. The plume three-dimensional diffusion monitoring device adopts an electrical monitoring sub-node design to achieve data communication and reliable connection, and adopts the electrical turbidity inversion model construction technology based on artificial neural network technology.

[0020] like Figure 7 As shown, the type II portable monitoring node device adopts a submerged buoy design, which can receive instructions to float up, and each part works independently. The type II portable monitoring node device includes a third glass float 32 and a node device frame, the third glass float 32 and the node device frame are connected by a third Kevlar cable 33, a fourth pressure-resistant float 34 is installed on the top of the node device frame, and a third acoustic communicator 35, an electrochemical sensor 36 and a type II monitoring node control compartment 37 are installed inside the node device frame; like Figure 8 As shown, the plume electrochemical sensor 36 mainly has an independently developed integrated electrochemical parameter monitoring system to achieve in-situ long-term monitoring of pH, Eh and conductivity. The Ti / ternary nickel-cobalt-manganese oxide modification technology for pH electrodes, the preparation technology of anti-polarization solid Ag / AgCl porous electrodes and the preparation technology of Ti3Pt coating electrodes for redox potential are developed; the plume electrochemical sensor 36 includes a sensor housing 39, and the left and right ends of the sensor housing 39 are respectively equipped with an electrical sensor connector 38 and an electrochemical sensor data connector 43, and the sensor housing 39 is internally equipped with an electrochemical sensor electrode 40, an electrochemical sensor circuit board 41 and an electrochemical sensor data collector 42, the electrochemical sensor electrode 40 is electrically connected to the electrical sensor connector 38, and the electrochemical sensor data connector 43 is electrically connected to the electrochemical sensor data collector 42.

[0021] The master control system collects sensor data through analog and digital interfaces, completes data collection, transmission, storage, and power supply control for all sensors, and adopts key technologies such as time synchronization technology and low-power stable operation technology. The communication and control of the surface communication buoy-central monitoring node-Type I portable node is realized based on the underwater acoustic communication machine, and the surface communication buoy and the central monitoring node acoustic communication machine are "double-backed up".

[0022] A monitoring method for an in-situ monitoring system for deep-sea mining plume diffusion, comprising the following steps: Step S1, platform deployment: The central monitoring node device is deployed through the ship-machine cable and arranged 50 m away from the mining vehicle in the actual mining operation area. This distance prevents the mining vehicle from being disturbed and affecting the mining operation, and determines that the operation point is in the mining vehicle operation area; Step S2, determine the flow direction: determine the plume flow direction according to the distance traveled by the mining vehicle to facilitate layout; Step S3, node layout: first, a central monitoring node device is deployed around the mining vehicle, and a type I portable monitoring node device is deployed on the back of the mining vehicle plume. Then, type I portable monitoring node devices and type II portable monitoring node devices are deployed every 1 km on both sides of the mining vehicle. The type I monitoring nodes and type II monitoring nodes are arranged in a hexagonal shape around the central node, covering the plume deployment range; like Fig. 9 As shown, the central monitoring node device is equipped with in-situ monitoring instruments and equipment, seawater batteries, a master control system, an acoustic communication device and other functional instruments and equipment, and operates in the mode of "cable lowering - automatic monitoring - self-floating recovery"; like Fig.10 As shown, the portable node transmits data to the monitoring platform master control through underwater acoustic communication, which transmits the multiple element data collected on the seabed to the surface communication buoy through underwater acoustic communication equipment. Finally, the communication buoy transmits the data to the shore-based receiving and processing system (buoy receiving shore station) through satellite communication equipment. The specific steps for deploying and recovering the central node monitoring device are as follows: Step S3-1, lowering with cable: using the geological compass of the mother ship to go down, hook the cable with the help of the acoustic releaser 3, and then lower it to the bottom of the seat, and then the acoustic releaser 3 is unhooked; Step S3-2, the equipment is powered by the seawater dissolved oxygen battery 8, and the lithium battery of the equipment itself is used to back up the plume particle monitoring system, plume redeposition thickness monitoring system, plume environment image monitoring device, and plume biochemical environment monitoring device carried by the central monitoring node to work continuously and uninterruptedly, collect and store data at any time, and perform wireless transmission; Step S4, network observation, according to the direction of travel and working model of the mining vehicle, the central monitoring node device, the type I portable monitoring node device, and the type II portable monitoring node device continue to perform network monitoring, and the type I and type II portable nodes are arranged in a hexagonal shape around the central node as a whole, and the data is gathered for the main control and the data is transmitted through acoustics; The data transmission mode of the deep-sea mining plume in-situ monitoring system is that the monitoring master control system includes the monitoring platform and the master control in the portable node, collects sensor data through analog and digital interfaces, and completes the data collection, transmission, storage, and power supply control of all sensors and portable nodes. The portable node transmits the data to the monitoring platform master control through hydroacoustic communication, and the latter transmits the multiple element data aggregated on the seabed to the surface communication buoy through hydroacoustic communication equipment. Finally, the communication buoy transmits the data to the shore-based receiving and processing system (buoy receiving shore station) via satellite communication equipment.

[0023] Instructions are sent in the laboratory, overtime unit, and user end, which are received by the acoustic releaser, and then the jettisoned weight is discarded. This is because the jettisoned weight is disconnected from the central monitoring node device. The buoyancy of the central monitoring node is greater than the gravity, and then the equipment begins to float slowly and floats to the water surface for equipment recovery.

[0024] The working mode of the deep-sea mining plume in-situ monitoring system is related to the central monitoring node master control system responsible for the power supply, communication and control of the monitoring equipment, and all equipment is connected to this system. In the type I portable monitoring node, the sediment trap works independently, and the plume three-dimensional diffusion monitoring system, communication system, etc. are connected to the node master control; in the type II monitoring node, the sensor works independently without overall control.

[0025] The working mode of the in-situ monitoring system for deep-sea mining plumes is to study the safe and reliable deployment technology of seabed monitoring platforms, portable nodes and surface communication buoys, and the underwater high-precision positioning technology, and build a seabed monitoring network in the monitoring area; use seabed mining disturbance test equipment as the disturbance source to carry out in-situ long-term monitoring, and portable monitoring nodes are deployed at the front and rear of the mining plume disturbance, which can monitor the three-dimensional diffusion of the plume in all directions and space.

[0026] Step S5: Data analysis: According to the analysis of the uploaded data, the plume three-dimensional diffusion in-situ monitoring sensor carried by the Type I portable monitoring node device uses natural potential, redox potential, and resistivity to jointly invert turbidity; The inversion formula is: Where ρ is the resistivity (Ω·m), S is the salinity (‰), T is the temperature (K), s is the type of suspended particles, and c is the concentration of suspended particles in seawater (g·L -1 ), k(S,T,s) is used to determine salinity S, temperature T, and plume particle type. x , the rate of change of resistivity ρ with plume concentration c. SP is the natural potential value (mV), S is the salinity, T is the temperature (K), x is the type of plume particles, Z is the water level height relative to the reference electrode (cm), and c is the concentration of suspended particles in seawater (g·L -1 ). Eh is the redox potential (mV), S is the salinity (‰), T is the temperature (K), x is the type of plume particles, pH is the acidity and alkalinity of the solution, and DO is the dissolved oxygen content of the solution (mg·L -1 ), c is the concentration of suspended particles in seawater (g·L -1 )、 j (S,T,s,pH,DO) is used to determine salinity S, temperature T, plume particle type x, solution pH, solution dissolved oxygen content DO, the redox potential Eh changes with plume concentration c According to the physical and chemical environment of the plume and the corresponding seabed sediment type, relevant adjustment coefficients can be made to obtain the relevant plume concentration.

[0027] In the description of the present invention, the term "plurality" refers to two or more than two. Unless otherwise clearly defined, the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention; the terms "connection", "installation", "fixation", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0029] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An in-situ monitoring system for deep-sea mining plume diffusion, characterized in that , including a central monitoring node device, 3 Type I portable monitoring node devices, 3 Type II portable monitoring node devices, and a sea surface monitoring buoy; The central monitoring node device comprises an instrument frame (5), the instrument frame (5) being divided into three parts: an upper part, a middle part and a lower part. The center position of the upper frame of the instrument frame (5) is connected to one end of a first Kevlar cable (1), the other end of the first Kevlar cable (1) is connected to a deployed and recovered pressure-resistant buoy (44), the upper frame of the instrument frame (5) is surrounded by a buoyant material (4) installed on the outside, the top of the buoyant material (4) is installed with an acoustic releaser (3), an Iridium beacon (11), an optical beacon (12) and an acoustic communication device (13), and four groups of first seabed pressure-resistant buoys (2) are installed at the four corners of the upper frame of the instrument frame (5). The upper frame of the instrument frame (5) is provided with a main control cabin (15), a dissolved oxygen sensor (16), a binocular camera control cabin (17), and a CTD sensor (18) in a clockwise manner. The bottom periphery of the upper frame of the instrument frame (5) is provided with a plume particle monitoring device (14), a plume environment image monitoring device (7), and a plume redeposition thickness monitoring device (6) in a clockwise manner. Four groups of seawater dissolved oxygen batteries (8) are placed in the middle frame of the instrument frame (5). The bottom frame of the instrument frame (5) is provided with four supporting legs and a bottom counterweight tray (10) is provided at the bottom through a counterweight unhooking device (9). The type I portable monitoring node device comprises a recovery beacon (19) and a sediment trap (24), the recovery beacon (19) and the sediment trap (24) being connected via a second Kevlar cable (22), four second glass floats (20) being installed inside the recovery beacon (19), a second acoustic communication device (21) being installed at the bottom of the recovery beacon (19), three plume three-dimensional diffusion monitoring systems (23) being installed at equal intervals on the second Kevlar cable (22), and a sediment trap battery being installed at the bottom of the sediment trap (24). The plume three-dimensional diffusion monitoring system (23) comprises a sensor outer chamber (28) and a watertight plug (27) connected to one end thereof, a circuit board (30) and a collector (31) are installed inside the sensor outer chamber (28), and a wiring electrode (29) is installed inside the watertight plug (27), the wiring electrode (29) is a platinum electrode evenly distributed at four positions, the ratio electrode and the natural potential electrode are both made of titanium alloy-graphene material, the redox electrode is a platinum electrode, and each sub-node is collected by an AD acquisition to realize the sequential collection of electrical parameters; The type II portable monitoring node device comprises a third glass float (32) and a node device frame, wherein the third glass float (32) and the node device frame are connected via a third Kevlar cable (33), a fourth pressure-resistant float (34) is installed on the upper part of the node device frame, and a third acoustic communicator (35), an electrochemical sensor (36) and a type II monitoring node control compartment (37) are installed inside the node device frame.

2. A deep sea mining plume diffusion in-situ monitoring system and monitoring method according to claim 1, characterized in that The plume redeposition thickness monitoring device (6) comprises a rotating motor cabin and an optical measurement cabin.

3. A deep-sea mining plume diffusion in-situ monitoring system and monitoring method according to claim 1, characterized in that ,The plume environment image monitoring device (7) includes a lighting unit and a binocular camera.

4. A deep-sea mining plume diffusion in-situ monitoring system and monitoring method according to claim 1, characterized in that The plume electrochemical sensor (36) comprises a sensor housing (39), wherein the left and right ends of the sensor housing (39) are respectively provided with an electrical sensor connector (38) and an electrochemical sensor data connector (43), wherein the sensor housing (39) is provided with an electrochemical sensor electrode (40), an electrochemical sensor circuit board (41) and an electrochemical sensor data collector (42), wherein the electrochemical sensor electrode (40) is electrically connected to the electrical sensor connector (38), and the electrochemical sensor data connector (43) is electrically connected to the electrochemical sensor data collector (42).

5. The monitoring method of the deep sea mining plume diffusion in-situ monitoring system as claimed in any one of claims 1 to 5, characterized in that , specifically including the following steps Step S1, platform deployment: The central monitoring node device is deployed through the ship-machine cable and arranged 50 m away from the mining vehicle in the actual mining operation area; Step S2, determining the flow direction: determining the plume flow direction according to the travel distance of the mining vehicle; Step S3, node deployment: First, the central monitoring node device is deployed around the mining vehicle, and the type I portable monitoring node device is deployed on the back of the mining vehicle plume. Then, the type I portable monitoring node device and the type II portable monitoring node device are deployed every 1 km on both sides of the mining vehicle, in a hexagonal arrangement, covering the plume deployment range; the steps for deploying and recovering the central monitoring node device are as follows: Step S3-1, lowering with cable: using the geological compass of the mother ship to go down, hook the cable with the help of the acoustic releaser (3), and then lower it to the bottom of the seat, and then the acoustic releaser (3) is unhooked; Step S3-2, the device is powered by the seawater dissolved oxygen battery (8), and the lithium battery of the device itself is used to back up the plume particle monitoring system, plume redeposition thickness monitoring system, plume environment image monitoring device, and plume biochemical environment monitoring device carried by the central monitoring node to work continuously and uninterruptedly, collect and store data at any time, and perform wireless transmission; Step S4, network observation, according to the direction of travel and working model of the mining vehicle, the central monitoring node device, the type I portable monitoring node device, and the type II portable monitoring node device continue to perform network monitoring, and are recycled in a hexagonal arrangement, and the data is gathered for the main control, and the data is transmitted through acoustics; Step S5: Data analysis: According to the analysis of the uploaded data, the plume three-dimensional diffusion in-situ monitoring sensor carried by the Type I portable monitoring node device uses natural potential, redox potential, and resistivity to jointly invert turbidity; The inversion formula is: Where ρ is the resistivity (Ω·m), S is the salinity (‰), T is the temperature (K), s is the type of suspended particles, and c is the concentration of suspended particles in seawater (g·L -1 ), k(S,T,s) is used to determine salinity S, temperature T, and plume particle type. x , the rate of change of resistivity ρ with plume concentration c; SP is the natural potential value (mV), S is the salinity, T is the temperature (K), x is the type of plume particles, Z is the water level relative to the reference electrode (cm), and c is the concentration of suspended particles in seawater (g·L -1 ); Eh is the redox potential (mV), S is the salinity (‰), T is the temperature (K), x is the type of plume particles, pH is the acidity and alkalinity of the solution, and DO is the dissolved oxygen content of the solution (mg·L -1 ), c is the concentration of suspended particles in seawater (g·L -1 )、 j (S,T,s,pH,DO) is used to determine salinity S, temperature T, plume particle type x , solution pH, solution dissolved oxygen content DO, redox potential Eh with plume concentration c The rate of change.

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