Mine transient electromagnetic three-component detection method

Abstract

The invention relates to the technical field of mine electromagnetic detection, and discloses a mine transient electromagnetic three-component detection method, which comprises the following steps: S1, selecting and preparing equipment, selecting transmitting equipment, selecting receiving equipment which comprises three sets of receiving coils or antennas consistent with the measurement direction of a three-component electromagnetic field, and configuring data acquisition equipment with anti-interference capability; s2, laying and planning measuring points, dividing an exploration area according to geological data, and dividing the area into a plurality of measuring grids; s3, calibration and system inspection: carrying out system calibration on the transmitting and receiving equipment; s4, formal data acquisition; s5, data storage and backup; s6, data preprocessing; s7, performing inversion and modeling; s8, performing three-dimensional imaging and geological interpretation; and S9, compiling a report. The three-component data of the electromagnetic field is collected, the spatial change characteristics of the electromagnetic field are comprehensively captured, the position, shape and conductivity distribution of the underground anomalous body are detected more accurately, and the limitation caused by traditional single-component measurement can be effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of mine electromagnetic detection, in particular to a mine transient electromagnetic three-component detection method. Background Art

[0002] Mine transient electromagnetic method is an important geophysical exploration method, which is widely used in the detection of mines and underground ore bodies. Traditional transient electromagnetic detection methods usually rely on single-component electromagnetic field measurement, focusing mainly on the electromagnetic field changes of horizontal or vertical components.

[0003] However, the limitation of single-component measurement is that it cannot fully reflect the three-dimensional characteristics of complex underground geological structures. Especially in underground exploration in complex environments such as mines, the electromagnetic response information of a single component is often not sufficient to accurately locate and describe the position, shape and conductivity distribution of underground anomalies. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a mine transient electromagnetic three-component detection method to solve the problem that single-component measurement cannot fully reflect the three-dimensional characteristics of complex underground geological structures.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A mine transient electromagnetic three-component detection method, comprising the following steps:

[0006] S1: Equipment selection and preparation

[0007] Select the transmitting equipment and determine the type, power and frequency of the transmitting system according to the exploration depth and the conductivity range of the target body;

[0008] Select receiving equipment, including three sets of receiving coils or antennas consistent with the measurement direction of the three-component electromagnetic field, and configure data acquisition equipment with anti-interference ability;

[0009] S2: Measurement point layout and planning

[0010] Divide the exploration area according to geological data, divide the area into multiple measurement grids, and design the measurement point layout to cover the target area;

[0011] A transmitting coil is arranged at each measuring point, and its direction, position and height are adjusted to be consistent with the expected electromagnetic field propagation direction;

[0012] Use the measuring tool to calibrate the direction of the receiving coil so that the receiving direction is strictly aligned with the set three-component direction;

[0013] S3: Calibration and system check

[0014] Perform system calibration on the transmitting and receiving equipment to ensure that the transmitting power, receiving sensitivity and time synchronization of the equipment meet the measurement requirements;

[0015] Conduct background noise testing to identify and record noise sources that may affect measurement accuracy and adjust equipment settings to reduce noise effects;

[0016] S4: Formal data collection

[0017] Continuous transient electromagnetic field emission is performed at each measuring point, and the receiving equipment records the three-component attenuation signal of the electromagnetic field;

[0018] Repeat the measurement at each measuring point at least 3 times, superimpose multiple measurement results to improve the signal-to-noise ratio, and record the environmental conditions of each measurement;

[0019] S5: Data storage and backup

[0020] Transfer the measurement data to the data storage device and then perform data backup;

[0021] S6: Data preprocessing

[0022] Perform time correction and coordinate conversion on the original measurement data to unify the data processing benchmark;

[0023] Through smoothing filtering and denoising algorithms, environmental and instrument noise can be eliminated to extract effective signals;

[0024] Use background noise data for noise subtraction to further improve signal quality;

[0025] S7: Inversion and Modeling

[0026] Perform preliminary inversion calculations to obtain a preliminary distribution model of underground conductivity and adjust model parameters based on the results;

[0027] Through iterative inversion technology and combined with geological prior information, the model is refined to obtain a more accurate underground structure model;

[0028] S8: 3D imaging and geological interpretation

[0029] The inverted conductivity data is converted into a three-dimensional underground model, and the conductivity changes at different depths are displayed through three-dimensional imaging;

[0030] Conduct geological analysis on the 3D imaging results and compare them with geological data to identify the location, shape and nature of underground anomalies;

[0031] S9: Report Writing

[0032] Organize data and analyze results to write exploration reports, including measurement methods, data processing procedures, 3D imaging results and geological interpretation.

[0033] Preferably, in the step S2, the layout of the measuring points further includes selecting the spacing and density of the measuring point layout according to the specific geological structure characteristics in the mine, optimizing the detection resolution and effectively covering the underground structure of the target area.

[0034] Preferably, in step S6, the data preprocessing step further includes applying adaptive filtering technology to enhance the recognition of effective signals, thereby improving the accuracy and reliability of data by eliminating nonlinear noise and system errors.

[0035] Preferably, in step S7, the inversion and modeling step further includes comparative analysis using a variety of inversion algorithms, including but not limited to finite element method, integral equation method and Monte Carlo simulation method.

[0036] Preferably, in the step S8, the three-dimensional imaging and geological interpretation step further includes refining and classifying different conductivity intervals, and improving the recognition accuracy of specific target bodies through layered processing. The specific target bodies include ore bodies and aquifers.

[0037] Preferably, after the step S3, a preliminary signal test is performed:

[0038] Before formal measurement, test transmission is carried out to receive and analyze preliminary signals and check whether the system is in good working condition;

[0039] The emission parameters are adjusted according to the test emission results to optimize the signal strength and detection depth. The emission parameters include pulse width and frequency.

[0040] Preferably, the preliminary signal test further includes dynamically adjusting the current waveform and transmission frequency of the transmitting device according to the results of the test transmission to adapt to the changes in the conductivity of different underground media.

[0041] Preferably, after the step S8, result verification and optimization are performed:

[0042] The detection results are verified through drilling verification, and based on the verification results, the inversion model is optimized and the interpretation of the underground structure is adjusted.

[0043] Preferably, the result verification and optimization step further includes performing multi-source data fusion analysis on the detection results, and comprehensively interpreting the drilling data, seismic exploration data and electromagnetic detection data to construct a more complete underground structure model.

[0044] The present invention provides a mine transient electromagnetic three-component detection method, which has the following beneficial effects:

[0045] 1. The present invention collects three-component data of the electromagnetic field to comprehensively capture the spatial variation characteristics of the electromagnetic field, making the detection of the position, shape and conductivity distribution of underground anomalies more accurate, and can effectively solve the limitations brought by traditional single-component measurement.

[0046] 2. The present invention adopts adaptive filtering and background noise subtraction technology, which can effectively remove electromagnetic noise in the complex environment of the mine, improve the clarity and effectiveness of the data, and thus improve the reliability of the inversion results.

[0047] 3. Through the combination of multiple iterative inversions and multiple inversion algorithms, and combined with geological prior information, the present method can construct a more accurate underground conductivity model, effectively reduce the uncertainty and error in the inversion process, especially under complex geological conditions, showing significant superiority.

[0048] 4. The present invention utilizes refined processed three-component data to construct a three-dimensional conductivity distribution map that can accurately reflect the details of the underground structure, especially the description of the boundary, shape and depth of the ore body is clearer, providing a reliable scientific basis for mine exploration and resource development. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a flow chart of a mine transient electromagnetic three-component detection method of the present invention. DETAILED DESCRIPTION

[0050] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Please see attached Figure 1 The embodiment of the present invention provides a mine transient electromagnetic three-component detection method, comprising the following steps:

[0052] S1: Equipment selection and preparation

[0053] Transmitter equipment selection:

[0054] a) Select a 10kW high frequency pulse current transmitter capable of providing a pulse frequency of 500Hz, suitable for detecting underground ore bodies at depths up to 300 meters. The transmitter is designed with an adjustable pulse width function to optimize signal propagation under different geological conditions.

[0055] b) Select a transmitting cable with anti-interference ability. The length is determined according to the actual depth of the mine and the location of the measuring point, and it is equipped with a durable coil frame to ensure the stability of the transmitting coil.

[0056] Receiving equipment selection:

[0057] a) The receiving device selects a high-sensitivity three-component coil. The effective capture frequency band of the coil is 10Hz to 1kHz, which can accurately measure the changes in the electromagnetic field in the mine.

[0058] b) Data acquisition equipment: A high-resolution (24-bit) digital acquisition system is selected, which has an automatic time synchronization function and supports the superposition processing of multiple measurement data. The data acquisition system is also equipped with a large-capacity storage unit to support long-term continuous operation.

[0059] Power system preparation:

[0060] a) Choose a mobile power system with sufficient capacity to ensure that the transmitter can work stably for a long time. The power system should have a voltage stabilization function to prevent the influence of power fluctuations in the mine on the transmitter power.

[0061] b) Prepare backup power supplies and generators to deal with emergencies or power failures.

[0062] S2: Measurement point layout and planning

[0063] Exploration area division:

[0064] a) According to the geological survey report of the mine, the target area is divided into 50mx50m grids, and each grid intersection is set as a measuring point. When dividing the grid, it is necessary to consider the estimated size and shape of the ore body to ensure that the distribution of the measuring points can cover the entire area of ​​the ore body.

[0065] b) For known geological anomaly areas (such as fault zones and fissure areas), the measurement points should be appropriately increased and the spacing can be reduced to 20m to improve the resolution.

[0066] Transmitter coil layout:

[0067] a) At each measuring point, choose an area with a flat ground and no obvious metal interference to lay out the transmitting coil. During the coil layout, use a level to ensure that the coil is laid flat, and use wooden stakes to fix the coil position to prevent the coil from moving during measurement.

[0068] b) Adjust the direction of the coil so that it is parallel to the main structure of the mine to ensure that the electromagnetic field propagates efficiently in the target area.

[0069] Receiving coil layout:

[0070] a) The layout requirements of the receiving coil are the same as those of the transmitting coil, and it needs to be strictly aligned with the three-component direction (Ex: east-west direction, Ey: north-south direction, Ez: vertical direction).

[0071] b) Use a laser rangefinder and a compass to accurately position and align the coils in the Ex and Ey directions, respectively, to ensure the directionality of the received signal.

[0072] c) The height of the receiving coil should be set to avoid being close to ground interference sources (such as metal objects, cables, etc.). It is usually installed at a height of 0.5 to 1 meter from the ground and isolated with insulating materials.

[0073] S3: Calibration and system check

[0074] Transmitter system calibration:

[0075] a) Turn on the transmitter and output a standard current signal without load. Measure the output current with a test instrument to confirm that it is consistent with the set value.

[0076] b) Use a signal generator to simulate different current pulses, detect the response speed and output accuracy of the transmitting device, and ensure that the device performance meets the detection requirements.

[0077] Receiving system calibration:

[0078] a) Place the receiving coil in a known standard electromagnetic field, record its output signal, and compare it with the theoretical value to calibrate the sensitivity and response frequency of the receiving system.

[0079] b) Adjust the gain and filter settings of the receiving equipment to ensure that the effective signal and background noise can be clearly distinguished in the complex electromagnetic environment of the mine.

[0080] Background noise test:

[0081] a) Perform a background noise test after the equipment is calibrated, turn off the transmitting equipment, and record the noise level of the receiving equipment in a static environment.

[0082] b) If the background noise is too high, check the possible interference sources in the mine (such as ventilation system, power lines) and take measures to reduce their impact, such as adjusting the measurement point location or adding a shielding layer.

[0083] Further, conduct preliminary signal testing

[0084] Test launch operation:

[0085] a) Start the transmitting device and transmit a 500 Hz current pulse according to the standard parameter settings. The receiving device simultaneously records the initial response of the electromagnetic field.

[0086] b) Analyze the received preliminary signal, focusing on the signal shape, attenuation rate and noise level to ensure that the amplitude of each component signal is within the expected range.

[0087] Parameter adjustment:

[0088] a) Based on the preliminary signal test results, adjust the width and frequency of the transmitted pulse to optimize the signal penetration depth and sensitivity. For example, if the signal decays too quickly, increase the pulse width or reduce the frequency to increase the detection depth.

[0089] b) Fine-tune the filter settings of the receiving equipment to maximize the valid signal while suppressing noise and interference.

[0090] S4: Formal data collection

[0091] Data collection operation:

[0092] a) At each measuring point, multiple electromagnetic pulses are transmitted continuously according to the preset transmission parameters, and the electromagnetic field attenuation signal after each transmission is recorded in real time by the receiving device.

[0093] b) After each measurement, record the environmental conditions (such as temperature and humidity) so that the impact of these factors on the signal can be considered in subsequent data analysis.

[0094] Multiple measurements and superposition:

[0095] a) Repeat the measurement at each measuring point for at least 5 times and record the received signal each time. Use the superposition function in the data acquisition system to superimpose multiple measurement results to improve the signal-to-noise ratio.

[0096] b) Perform preliminary data analysis immediately after each measurement to confirm the signal quality. If the signal quality is poor, re-measure or adjust the transmission parameters.

[0097] S5: Data storage and backup

[0098] Data transmission:

[0099] a) After the measurement is completed, all raw data are transferred from the receiving device to the computer storage device on site. During the transmission process, ensure data integrity to avoid loss or damage.

[0100] b) Use dedicated data transmission software to ensure that data is not tampered with during transmission and generate data transmission logs for subsequent review.

[0101] Data backup:

[0102] a) After the original data is stored, make a data backup immediately and copy the data to multiple physical storage media (such as external hard disk, USB memory).

[0103] b) Upload data backup to the cloud storage platform through encrypted transmission to ensure that data can be quickly restored in unexpected situations (such as equipment damage, data loss).

[0104] S6: Data preprocessing

[0105] Time Correction:

[0106] a) Perform unified time correction on the data of all measurement points to ensure that the time base of all data is consistent. This step requires the use of high-precision time synchronization equipment combined with GPS timestamps for calibration.

[0107] b) Arranging the time-corrected data in a time series to generate a continuous electromagnetic field response sequence.

[0108] Noise Removal:

[0109] a) Use adaptive filtering technology to process the measured data, eliminate high-frequency noise and random interference signals, and extract effective electromagnetic field attenuation information.

[0110] b) Combined with the background noise data, the background noise subtraction algorithm is applied to correct the background noise of the data at each measuring point to improve the effectiveness of the signal.

[0111] Differential processing:

[0112] a) Perform differential calculation on the preprocessed data to further remove systematic errors and linear interference to ensure the accuracy of the data.

[0113] b) Generate the net electromagnetic field attenuation curve of each measuring point for subsequent inversion calculation.

[0114] S7: Inversion and Modeling

[0115] Preliminary inversion calculation:

[0116] a) Use the finite element method to perform preliminary inversion calculations on the data of each measuring point to generate a preliminary underground conductivity distribution model. In the inversion calculation, geological prior information (such as the layered structure of the mine and the location of the known ore body) needs to be considered as the initial condition.

[0117] b) Adjust the parameters of the preliminary model to improve the fit with the measured data. After the preliminary model is completed, generate the underground conductivity slice map of each measuring point.

[0118] Refined inversion:

[0119] a) Based on the preliminary inversion model, the model is refined using multiple iterative inversion techniques, taking into account the complex geological structures in the mine, such as fracture zones and folds.

[0120] b) Combined with the drilling data in the mine, local optimization is performed on the key areas of the inversion model to ensure the accuracy of the model.

[0121] Model Validation:

[0122] a) Compare the results of the inversion model with the known geological information to verify the rationality of the model. If obvious deviations are found, the model parameters need to be readjusted and the inversion calculation needs to be performed.

[0123] b) Generate the final three-dimensional distribution model of underground conductivity and export slices at different depths for geological interpretation.

[0124] S8: 3D imaging and geological interpretation

[0125] 3D Imaging:

[0126] a) Import the inverted conductivity data into the 3D imaging software to generate underground structure models at different depths in the mine. Different color codes are used in the model to represent different conductivity values, helping to intuitively identify ore bodies, aquifers and other abnormal bodies.

[0127] b) Adjust the viewing angle and slice position of the 3D model to focus on areas where ore bodies may exist and generate clear 3D images for analysis.

[0128] Geological analysis:

[0129] a) Conduct a detailed analysis of the abnormal conductivity areas in the 3D model and determine the ore bodies, faults or fissures that these areas may correspond to, based on the geological background of the mine.

[0130] b) Based on the analysis results, compare with the mine's existing mining plan, evaluate the mining feasibility of the ore body, and propose possible ore body boundaries, shapes and depths.

[0131] Report written by:

[0132] a) Prepare an exploration report based on the results of 3D imaging and geological analysis. The report content includes the purpose and method of exploration, data processing process, inversion and modeling results, 3D imaging map and geological interpretation.

[0133] b) The report should include detailed data and interpretation results of the inversion model, and provide charts and slice diagrams to help readers understand the specific results of the detection.

[0134] Further verification and optimization of the results

[0135] Drilling Verification:

[0136] a) Drill holes at key ore body locations shown in the 3D model to obtain actual geological samples. Verify the accuracy of the detection results by comparing the drilling data with the model data.

[0137] b) If there is a discrepancy between the drilling results and the model, analyze the cause and readjust the inversion model to ensure the credibility of the final results.

[0138] Data Fusion:

[0139] a) Fusion analysis of transient electromagnetic detection data with the results of other geophysical exploration methods (such as seismic exploration and gravity exploration) to integrate various types of data and improve the integrity and accuracy of underground structure models.

[0140] b) Use the data fusion results to finally optimize the inversion model and generate a unified underground 3D structural model for mine planning and mining.

[0141] S9: Report Writing

[0142] Full report written by:

[0143] a) All data processing, analysis processes and results are organized into a complete exploration report. The report structure includes: detection background, measurement methods, data processing steps, inversion and modeling, 3D imaging and geological interpretation, verification and optimization.

[0144] b) The report should include detailed data tables, model images, slice diagrams and geological analysis results to ensure that the report content is clear and comprehensive and provide strong support for subsequent mining decisions.

[0145] Report delivery and presentation:

[0146] a) Deliver the final exploration report and 3D model results to the mine management. To help non-professionals understand, a 3D dynamic display of the model can be prepared to illustrate the location, shape and depth of the ore body.

[0147] b) Provide necessary follow-up support during the delivery process, such as explaining the report content, answering technical questions, and providing further exploration or mining suggestions based on customer needs.

[0148] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A mine transient electromagnetic three-component detection method, characterized in that: The following steps are involved: S1: Equipment selection and preparation Select the transmitting equipment and determine the type, power and frequency of the transmitting system according to the exploration depth and the conductivity range of the target body; Select receiving equipment, including three sets of receiving coils or antennas consistent with the measurement direction of the three-component electromagnetic field, and configure data acquisition equipment with anti-interference ability; S2: Measurement point layout and planning Divide the exploration area according to geological data, divide the area into multiple measurement grids, and design the measurement point layout to cover the target area; A transmitting coil is arranged at each measuring point, and its direction, position and height are adjusted to be consistent with the expected electromagnetic field propagation direction; Use the measuring tool to calibrate the direction of the receiving coil so that the receiving direction is strictly aligned with the set three-component direction; S3: Calibration and system check Perform system calibration on the transmitting and receiving equipment to ensure that the transmitting power, receiving sensitivity and time synchronization of the equipment meet the measurement requirements; Conduct background noise testing to identify and record noise sources that may affect measurement accuracy and adjust equipment settings to reduce noise effects; S4: Formal data collection Continuous transient electromagnetic field emission is performed at each measuring point, and the receiving equipment records the three-component attenuation signal of the electromagnetic field; Repeat the measurement at each measuring point at least 3 times, superimpose multiple measurement results to improve the signal-to-noise ratio, and record the environmental conditions of each measurement; S5: Data storage and backup Transfer the measurement data to the data storage device and then perform data backup; S6: Data preprocessing Perform time correction and coordinate conversion on the original measurement data to unify the data processing benchmark; Through smoothing filtering and denoising algorithms, environmental and instrument noise can be eliminated to extract effective signals; Use background noise data for noise subtraction to further improve signal quality; S7: Inversion and Modeling Perform preliminary inversion calculations to obtain a preliminary distribution model of underground conductivity and adjust model parameters based on the results; Through iterative inversion technology and combined with geological prior information, the model is refined to obtain a more accurate underground structure model; S8: 3D imaging and geological interpretation The inverted conductivity data is converted into a three-dimensional underground model, and the conductivity changes at different depths are displayed through three-dimensional imaging; Conduct geological analysis on the 3D imaging results and compare them with geological data to identify the location, shape and nature of underground anomalies; S9: Report Writing Organize data and analyze results to write exploration reports, including measurement methods, data processing procedures, 3D imaging results and geological interpretation.

2. A mine transient electromagnetic three-component detection method according to claim 1, characterized in that: In the step S2, the arrangement of the measuring points further includes selecting the spacing and density of the measuring points according to the specific geological structure characteristics in the mine, optimizing the detection resolution and effectively covering the underground structure of the target area.

3. A mine transient electromagnetic three-component detection method according to claim 1, characterized in that: In the step S6, the data preprocessing step further includes applying adaptive filtering technology to enhance the recognition of effective signals and improve the accuracy and reliability of data by eliminating nonlinear noise and system errors.

4. A mine transient electromagnetic three-component detection method according to claim 1, characterized in that: In the step S7, the inversion and modeling step further includes comparative analysis using a variety of inversion algorithms, including but not limited to finite element method, integral equation method and Monte Carlo simulation method.

5. A mine transient electromagnetic three-component detection method according to claim 1, characterized in that: In the step S8, the three-dimensional imaging and geological interpretation step further includes refining and classifying different conductivity intervals, and improving the recognition accuracy of specific target bodies through layered processing. The specific target bodies include ore bodies and aquifers.

6. A mine transient electromagnetic three-component detection method according to claim 1, characterized in that: After the S3 step, a preliminary signal test is performed: Before formal measurement, test transmission is carried out to receive and analyze preliminary signals and check whether the system is in good working condition; The emission parameters are adjusted according to the test emission results to optimize the signal strength and detection depth. The emission parameters include pulse width and frequency.

7. A mine transient electromagnetic three-component detection method according to claim 6, characterized in that: The preliminary signal test further includes dynamically adjusting the current waveform and transmission frequency of the transmitting device according to the results of the test transmission to adapt to the changes in the conductivity of different underground media.

8. A mine transient electromagnetic three-component detection method according to claim 1, characterized in that: After the S8 step, the results are verified and optimized: The detection results are verified through drilling verification, and based on the verification results, the inversion model is optimized and the interpretation of the underground structure is adjusted.

9. A mine transient electromagnetic three-component detection method according to claim 8, characterized in that: The result verification and optimization step further includes performing multi-source data fusion analysis on the detection results, and comprehensively interpreting the drilling data, seismic exploration data and electromagnetic detection data to construct a more complete underground structure model.

Images