A hard rock type rare earth ore exploration method and system

Abstract

The application discloses a hard rock type rare earth ore exploration method and system, relates to the technical field of mineral exploration, and comprises the following steps: according to geological scientific data of a target region, a prospecting prospective area in the target region is delineated based on a regional metallogenic prediction model; large-scale geological mapping and ground gamma energy spectrum measurement are carried out in the prospecting prospective area, lithology-structure information is superimposed, and a high radioactivity value target area is screened out; portable XRF detection is arranged in the high value target area, a rare earth element semi-quantitative result is used as a basis, and an ore-hosting geological body is delineated; CSAMT measurement is implemented on the ore-hosting geological body, electromagnetic data inversion is carried out, and low-resistance mineralized bodies and ore-controlling structures are determined; and based on the low-resistance mineralized bodies and the ore-controlling structures, slot exploration and drilling engineering means are used for field system exploration. The application can improve the ore-prospecting efficiency and accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mineral exploration, in particular to a hard rock type rare earth ore exploration method and system. BACKGROUND

[0002] Rare earth ore is an important strategic mineral resource, and hard rock type rare earth ore is an important part of the global rare earth supply chain, especially in light rare earth supply, key metal security and high-tech industry application, which has irreplaceable strategic value. Hard rock type rare earth ore refers to a rare earth ore deposit type in which rare earth elements are hosted in primary rocks or minerals and need to be crushed and beneficiated by physical or chemical methods for extraction. This type of deposit is usually directly related to magmatic rocks, hydrothermal activity or metamorphism, and rare earth minerals exist in the form of independent minerals (such as bastnaesite, monazite, xenotime, etc.) rather than ion adsorption state. This type of rare earth ore is usually difficult to locate, and the ore body is often in vein or disseminated form, small in size and scattered in distribution, and mostly concealed, which brings great challenges to mineral exploration. How to achieve breakthrough in hard rock type rare earth ore exploration and improve exploration efficiency is a research hotspot today.

[0003] At present, there is no comprehensive technical method system for hard rock type rare earth ore exploration in the domestic and foreign market. SUMMARY

[0004] The purpose of the present application is to provide a hard rock type rare earth ore exploration method and system, which can significantly improve the efficiency and accuracy of exploration.

[0005] To achieve the above purpose, the present application provides the following solutions:

[0006] In a first aspect, the present application provides a hard rock type rare earth ore exploration method, comprising:

[0007] Obtaining geological scientific data of a target area.

[0008] Based on the regional metallogenic prediction model, the target area is delineated according to the geological scientific data of the target area.

[0009] Large-scale geological mapping and ground gamma-ray spectrometry are carried out in the prospecting prospective area, and lithology-structure information is superimposed to screen out high radioactivity target areas.

[0010] Portable XRF detection is deployed in the high-value target area, and based on the semi-quantitative results of rare earth elements, the ore-hosting geological body is delineated.

[0011] CSAMT measurement is carried out on the ore-hosting geological body, and through electromagnetic data inversion, low-resistance mineralized body and ore-controlling structure are determined.

[0012] Based on the low-resistance mineralization body and the ore-controlling structure, the field system exploration is carried out by using the trenching and drilling engineering means.

[0013] In a second aspect, the present application provides a hard rock type rare earth ore exploration system, comprising:

[0014] The data acquisition module is configured to acquire geological scientific data of a target region.

[0015] The prospecting prospective area determination module is configured to delineate a prospecting prospective area in the target region based on a regional ore-forming prediction model according to the geological scientific data of the target region.

[0016] The target area determination module is configured to perform large-scale geological mapping and ground gamma energy spectrum measurement in the prospecting prospective area, superimpose lithology-structure information, and screen out a high-value target area of radioactivity.

[0017] The ore-hosting geological body determination module is configured to deploy a portable XRF detector in the high-value target area, and delineate an ore-hosting geological body based on semi-quantitative results of rare earth elements.

[0018] The inversion module is configured to perform CSAMT measurement on the ore-hosting geological body, determine a low-resistance mineralization body and an ore-controlling structure through electromagnetic data inversion.

[0019] The exploration module is configured to perform field system exploration by using the trenching and drilling engineering means based on the low-resistance mineralization body and the ore-controlling structure.

[0020] According to the specific embodiments provided by the present application, the following technical effects are disclosed:

[0021] The present application provides a hard rock type rare earth ore exploration method and system. First, by acquiring geological scientific data of a target region, the ore-forming region can be scientifically predicted, the prospecting range can be reduced, blind exploration can be avoided, and the prospecting efficiency can be improved. Second, based on the geological scientific data, based on the regional ore-forming prediction model, the prospecting prospective area in the target region is delineated, and combined with large-scale geological mapping and ground gamma energy spectrum measurement, lithology-structure information is superimposed, which can accurately locate the prospecting prospective area and the high-value target area, further reducing the exploration range and improving the prospecting accuracy. Third, the semi-quantitative analysis of rare earth elements can be quickly carried out by using the portable XRF detector, which can provide accurate targets for subsequent electromagnetic measurement, and further improve the pertinence and efficiency of the exploration. Finally, by performing CSAMT measurement on the ore-hosting geological body and combining electromagnetic data inversion technology, the low-resistance mineralization body and the ore-controlling structure can be determined, which provides a reliable basis for field system exploration. On this basis, the trenching and drilling engineering means are used for verification, which can efficiently and accurately find the ore body, and significantly improve the prospecting efficiency and accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0023] Figure 1 A hard rock type rare earth ore exploration method flow chart is provided for an embodiment of the present application.

[0024] Figure 2 A technical roadmap is provided for an embodiment of the present application.

[0025] Figure 3 A ground gamma-ray spectrometry work flow chart is provided for an embodiment of the present application.

[0026] Figure 4 A ground gamma-ray spectrometry anomaly delineation result plan view is provided for an embodiment of the present application.

[0027] Figure 5 A portable XRF instrument test data physical map is provided for an embodiment of the present application.

[0028] Figure 6 A CSAMT work flow chart is provided for an embodiment of the present application.

[0029] Figure 7 A CSAMT observation device schematic diagram is provided for an embodiment of the present application.

[0030] Figure 8 AMTC-30 2025 is provided for an embodiment of the present application # Magnetic rod calibration amplitude-frequency and phase-frequency diagram.

[0031] Figure 9 2057 is provided for an embodiment of the present application # Host calibration amplitude-frequency and phase-frequency diagram.

[0032] Figure 10 2504 is provided for an embodiment of the present application # Host calibration amplitude-frequency and phase-frequency diagram.

[0033] Figure 11 2486 is provided for an embodiment of the present application # Host calibration amplitude-frequency and phase-frequency diagram.

[0034] Figure 12 PT1 profile comprehensive inference result is provided for an embodiment of the present application Figure 1 .

[0035] Figure 13The PT1 profile comprehensive inference result provided for an embodiment of the present application Figure 2 .

[0036] Figure 14 The functional module schematic diagram of a hard rock type rare earth ore exploration system provided for an embodiment of the present application. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0038] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0039] Embodiment one

[0040] As shown in the embodiment, the present embodiment provides a hard rock type rare earth ore exploration method, comprising: Figure 1

[0041] Step 101: Obtain geological scientific data of a target area.

[0042] Step 102: According to the geological scientific data of the target area, based on a regional metallogenic prediction model, delineate a prospecting prospective area in the target area.

[0043] Step 103: Perform large-scale geological mapping and ground gamma energy spectrum measurement in the prospecting prospective area, superimpose lithology-structure information, and screen out a high-value radioactive target area.

[0044] Step 104: Deploy a portable XRF detector in the high-value target area, based on semi-quantitative results of rare earth elements, delineate an ore-hosting geological body.

[0045] Step 105: Perform CSAMT measurement on the ore-hosting geological body, determine a low-resistance mineralized body and an ore-controlling structure through electromagnetic data inversion.

[0046] Step 106: Based on the low-resistance mineralized body and the ore-controlling structure, use trenching and drilling engineering means to perform field system exploration.

[0047] ​The application aims to provide a hard rock type rare earth ore exploration comprehensive technical method system establishment and application, the method adopts multi-level concealed ore body identification and verification exploration technology application of prospect delineation and screening, target area optimization and positioning, anomaly verification and verification, and the like, and by means of geological, geophysical, remote sensing and other multi-disciplinary and multi-field cross technical means, a set of applicable, efficient and perfect exploration technical method system is summarized and refined. The application can provide a basis for hard rock type rare earth ore concealed ore body prospecting and ore-forming feature research.

[0048] In some embodiments, when steps 101-106 are performed, as shown in Figure 2 , specifically, the following can be performed:

[0049] 1) The system collects regional geology, regional mineral resources, geophysical, geochemical, remote sensing and other data. Comprehensive analysis and research of La, Ce, Y, Nb, Ba (Br), Th (U), Pb, Mo, F and other element combination anomalies; analysis and research of regional geology, regional mineral resources, mineralization alteration and other characteristics, focusing on the analysis of regional fault zone characteristics; analysis and research of regional magmatic rock activity, focusing on the analysis and research of alkaline rock, carbonatite complex characteristics; analysis and research of airborne gamma radiation measurement anomaly characteristics; through rare earth metallogenic theory, based on comprehensive analysis, delineate and screen the prospecting prospect area.

[0050] Specifically, in the embodiment, the system collects regional geology, regional mineral resources, geochemistry, geophysics, remote sensing and other data. According to the 1:100,000 airborne radiation measurement, one anomaly is delineated, which is large in size, irregular belt-shaped, elliptical or oblate elliptical, about 8.8 km long, 1.5-2.0 km wide, with obvious anomaly center and large radiation intensity, good anomaly shape, especially the secondary anomaly in the south, which has typical ore-induced anomaly characteristics. The area is located in the west side of the southern section of Yishu fault zone, and the structure in the area is mainly fault, and the magmatic rock is mainly Mesozoic Yanshanian alkaline complex. Through analysis and research, the anomaly is generally 12γ-20γ, which is closely related to Yanshanian alkaline rock. The data formed by 1:200,000 geochemical exploration scanning shows that there is one La anomaly in the area, with an anomaly lower limit of 60.8×10 -6 , a maximum value of 500×10 -6 , an anomaly near the south-north direction, 8500m long from south to north, 3400m wide from east to west, wider in the south and narrower in the north, with an area of 26.97km 2La anomaly and airborne anomaly basically correspond, and are in good agreement. The southern part is a large heterolithic body, and the northern part is some small rock branches. The anomaly and Mesozoic alkaline magmatic rocks correspond well, and the widest part corresponds to the heterolithic body. Mineralization and alteration are developed in the area, mainly including silicification, fluoritization, pyritization, baritization, limonitization, sericitization (biotitization), carbonatization, etc., which are related to rare earth elements, gold and polymetallic mineralization. The most developed are multiple alterations along the fracture or fissure structure in the form of a belt. Based on the above analysis and research results, the area shows good prospecting prospects for rare earth minerals and great resource potential.

[0051] 2) In the range of the metallogenic prospect area, carry out large-scale fine geological mapping and ground gamma energy spectrum measurement. Through the delineation of radioactive comprehensive anomaly and superposition with geological map, screen high-value areas with lithology-structure coincidence, realize accurate selection and focusing of prospecting target area. As shown in the following table. Figure 3

[0052] 2.1) Large-scale fine geological mapping (1:10,000-1:2,000):

[0053] The key is to use the tracing method combined with the crossing method to trace and clarify the key areas, key geological boundaries, and important geological bodies. The core work task is to analyze the lithology-structure and to demarcate the contact zone of ore-bearing rock mass (carbonatite, alkaline rock, syenite-granite), primary fissure zone and alteration zoning, to identify the ore-controlling structures such as fracture intersection position, rock mass cold shrinkage joint, to divide the alteration types and zoning, and to record the mineral assemblage, structure, mineralization intensity and other mineralization characteristics.

[0054] Specifically, in this embodiment, 1:10,000 fine geological mapping is carried out, and the key areas, key geological boundaries, and important geological bodies are traced and clarified. The tracing method is mainly used, combined with the crossing method.

[0055] ​The target area is of medium structural complexity, and the number of geological points and routes is not limited, and the point-line density is not specifically required, with the purpose of reasonably controlling and clarifying the main geological bodies. For important sections such as mineralization and structural alteration zones, appropriate densification is made according to the specific circumstances to accurately reflect their characteristics. In the mapping, specimens of rocks, ores and other structural phenomena that are difficult to identify are collected and identified or studied in a timely manner, and sketches or photographs are taken of important geological phenomena. The geological mapping unit is a section, and the content of the geological point description mainly includes: rock assemblage characteristics, rock name, rock characteristics (color, weathering characteristics, mineral composition, structure, structure, etc.), alteration and mineralization phenomena, vein (layer), rock vein name, rock and mineral characteristics, occurrence, thickness, and penetration relationship; occurrence, nature, contact relationship, vertical and horizontal changes of geological bodies and geological structures (folds, faults, fracture zones, etc.). Important geological bodies, structures, contact zones, ore-bearing layers, and mineralized alteration zones are traced along the strike, and important mineralization clues are revealed using trench exploration projects.

[0056] 2.2) Ground gamma-ray spectrometry:

[0057] Combined with large-scale geological mapping results, suitable measurement grid is selected for ground gamma-ray spectrometry, which aims to further delineate the radioactive anomaly area related to rare earth minerals, identify the exact location of the anomaly source, and control the target geological body. The range of the center distance of the grid is 20-250 m, and the range of the point distance is 5-50 m.

[0058] 2.2.1) Equipment calibration:

[0059] Before the work is carried out, the equipment will be sent to the measurement station for calibration to ensure the accuracy and consistency of the equipment.

[0060] 2.2.2) Background measurement:

[0061] The water method is usually used. Before the work is carried out, a freshwater area with a water depth of more than 1.5 m, a water surface diameter of more than 2 m, and no radioactive pollution of water quality is selected. The spectrometer probe is wrapped with clean non-radioactive plastic film to make it waterproof, and then the probe is inserted into the water 40 cm deep in the center to measure. Single measurement time is 120 s, and measurement is performed for more than 30 times, and the average count rate of each channel is calculated as the radioactivity background of the channel.

[0062] 2.2.3) Consistency check:

[0063] After the instrument completes the calibration, all the ready-to-work spectrometers are organized to perform synchronous continuous measurement at the same measurement point, the observation curves are compared, and the mean square error of eU, eTh and K content is calculated to determine the consistency of each spectrometer meets the requirements.

[0064] 2.2.4) Short-term stability check:

[0065] The field short-term stability of the instrument is checked every other month. At the reference point in the survey area (within 5 m of no tall buildings), the measurement time is 120 s, and the measurement is repeated more than 100 times. The variance and average value of each channel are calculated, and the variance is compared. If the variance is less than the average value, it is considered that the counting error meets the radioactive statistical rules.

[0066] 2.2.5) Long-term stability check:

[0067] The long-term stability of the instrument in the field is checked before and after the instrument is used every day. A point is selected near the site (within 5 m of no tall buildings), and the eU, eTh, and K contents at the point are measured by the instrument before and after work every day. The counting time is 60 seconds each time, and the average of 5 readings is recorded. The measurement results of each time are plotted as eU, eTh, and K content scatter plots in chronological order. Ensure that the stability of all instruments meets the specification requirements. If there is an out-of-tolerance phenomenon (more than ± 15%), repeat the measurement, and stop the field work of the unqualified instrument; if the instrument is found to be unqualified after work, the measurement results of the instrument on that day are invalid.

[0068] 2.2.6) Working condition check:

[0069] Immediately check the voltage and stability spectrum of the instrument after finding abnormalities during field measurement to determine the reliability of the abnormalities and record them on the table to avoid data distortion caused by unstable instrument working conditions.

[0070] 2.2.7) Data collection:

[0071] Gamma-ray spectrometry is carried out in two-person teams, one person reading and one person recording. During measurement, the probe is straightened on a relatively flat bedrock outcrop or ground to ensure a radiation solid angle of 2π. The observation method, observation accuracy, and measurement geometry in the same survey area are consistent.

[0072] Content measurement is used, and the single measurement time is 60 seconds, with 1 reading. When encountering abnormalities, check the instrument voltage and stability spectrum to determine whether the abnormality is caused by geological bodies. If so, repeat the measurement 3 times to take the average value, and record the interference area, special terrain, ground objects, geological phenomena, and soil moisture. Stop observation immediately when it rains, and start work after the soil is dry.

[0073] All work results on the same day are arranged and self-checked and mutual checked in time after the work is completed every day. The working condition of the instrument is checked every day, and the instrument stability scatter plot is drawn.

[0074] 2.2.8) Quality check:

[0075] The check points are arranged in the abnormal area and the background area, the check proportion is greater than 10%, and the total point number is not less than 30; 100% of the abnormal points (zones) with doubts, mineralization and geological significance are checked, 50% of the general abnormal points (zones) are checked, and the background field is traced to 3-5 measuring points; the inspection line is arranged on the profile with geological significance or questionable work quality, and the mutual inspection or self-inspection method is used.

[0076] 2.2.9) Indoor data arrangement:

[0077] A, eU, eTh, K content calculation:

[0078] The instrument used can directly input the calibrated coefficient into the notebook for storage. In the field work, the notebook can directly calculate the U, Th, K and total content according to the saved parameters.

[0079] B, Actual material map compilation:

[0080] The topographic map with greater than or equal to the working precision is used as the base map of the actual material map, and the contents of the map include the measuring point number, eU, eTh, K content of each measuring point, inspection measurement position and number, rock sampling position and other work results.

[0081] C, Parameter statistics and determination of abnormal lower limit:

[0082] The eU, eTh, K and Tc content background value (X), standard deviation (S) and variation coefficient (CV) of the rock mass in the survey area are calculated.

[0083] The following formula is used to calculate each parameter:

[0084] .

[0085] .

[0086] .

[0087] In the formula: X is the background value, S is the standard deviation, C V is the variation coefficient, X i is the content value of the i-th measuring point element, and n is the sample number.

[0088] The characteristic parameters calculated from the geological background and geophysical survey data in the survey area are combined with the actual topographic and geological characteristics to determine the element abnormal lower limit (T) = background value (X) + 2 standard deviation (S).

[0089] D, Result map compilation

[0090] The isograms of eU, eTh, K and total content and the composite anomaly map of ground gamma-ray spectrometry are shown in the figure. The interval of isograms is determined according to the eU, eTh, K content and standard deviation of the whole survey area. The coloring refers to the order in Table 1, the background value area is colored blue, and the abnormal value area is colored red. The eU, eTh, K anomalies are plotted on one figure to form a composite anomaly which is closely related to the geological and ore-forming conditions of the multiple single anomalies. Specifically, the ground gamma-ray spectrometry anomaly delineation result plan view is shown in Figure 4 .

[0091] Table 1 Coloring requirements of content isograms

[0092]

[0093] In this embodiment, the scale of ground gamma-ray spectrometry measurement is 1:10000, the grid is 100m×20m, and the azimuth angle of the survey line is 110°. An ARD type portable multi-channel gamma-ray spectrometer is used. Before formal production, the project team members went to the Radioactive Measurement Exploration Metrology Station to calibrate the instrument. The short-term stability of the instrument is checked every two months. The long-term stability of the instrument is checked before and after using the instrument every day. A point is selected near the residence (there are no high buildings within a distance of 2m), and the eU, eTh, K content of the point is measured by the instrument before and after work every day. The counting time is 60" each time, and the average value of two readings is taken. The measurement results of each time are arranged in chronological order to make eU, eTh, K content. The working state of the instrument and the related parameters are checked every 2h during the field measurement and after the anomaly is found. Consistency measurement is carried out before and after formal work. Specifically, a profile with certain magnetic field variation is selected in the survey area, 34 observation points are arranged at equal distances on the profile, and the observation points are observed back and forth. The field production instrument is used for observation, and finally the consistency mean square error of the four instruments is calculated according to the following formula, and the formula for calculating the total mean square error is:

[0094] .

[0095] In the formula, v i is the difference between a certain observation value (including all values participating in the calculation of the average value) and the average of each observation value at the point; n is the sample number, i=1, 2, …n; m is the total number of observations, which is equal to the sum of all observation times at each check point.

[0096] The radioactivity background measurement is carried out by the water method. Then the data acquisition and quality inspection are carried out, the eU, eTh, K content calculation and parameter statistics (Table 2) are carried out, and the anomaly lower limit in the survey area is determined. Through calculation, the anomaly lower limits of each element are: TU=5.6×10 -6 , TTh=41.4×10 -6 , TK=5.4×10-2 TTc=39.0x10 -6 .

[0097] Table 2 Statistical table of characteristic parameters

[0098]

[0099] According to the achievement map preparation requirements, the isograms of eU, eTh, K and total path content and the comprehensive achievement map of ground gamma ray spectrum are prepared. Through the gamma ray spectrum measurement, it is found that the eTh content anomaly has good continuity and regular anomaly shape, so the radioactive anomaly is mainly delineated according to the anomaly delineation principle combined with the eTh content anomaly, and 4 radioactive anomalies are delineated in the survey area, among which the Dγ-1 anomaly is a combined anomaly with 4 obvious anomaly centers, and the anomaly peak is high, all of which are higher than 60x10 -6 Above all, the fracture structure in the anomaly area is developed, which is the main distribution area of alkaline complex rock mass. The lithology is mainly quartz syenite porphyry and aegirine augen porphyry, which corresponds to the anomaly DL-1 of the airborne anomaly. A large number of rare earth ore veins are found in the anomaly and its vicinity, and the anomaly shape is good.

[0100] 3) In the high value area of radioactive anomaly, alteration zone and mineralized outcrop, a portable XRF analyzer is used for rapid identification and semi-quantitative detection of rare earth elements, to realize rapid verification of the prospecting prediction target area, further reduce the prospecting target area, and delineate the ore-hosting geological body.

[0101] Specifically, in this embodiment, a portable XRF analyzer is used for rapid identification and semi-quantitative detection of rare earth elements in the high value area of radioactive anomaly, alteration zone and mineralized outcrop. Through rapid verification by the portable XRF analyzer, it is found that the ore body is mainly distributed in the interior and edge of the Mesozoic alkaline magmatic rock (syenite porphyry and diorite porphyrite) body, which is controlled by the north-west-west fault and fissure, thereby further reducing the prospecting target area and locking the ore-hosting geological body. The test data of the portable XRF instrument are shown in Table 2. Figure 5

[0102] 4) Rare earth mineralization is often related to alkaline rock / carbonatite, showing low resistance (<100Ω·m) or high resistance-low resistance transition zone. Controlled source audio frequency magnetotelluric sounding measurement (CSAMT) is carried out on the delineated ore-hosting geological body, after collecting electromagnetic data, using comprehensive inversion technology, combined with existing geological and geophysical information, the ore-controlling structure, the deep shape, scale, occurrence and depth of the concealed ore body are inverted and constrained.

[0103] As Figure 6 ​As shown, CSAMT by artificial emission audio electromagnetic signal (0.1 Hz ~ 10 kHz), measure the ground electric field (Ex) and magnetic field (Hy) component, calculate the Cagniard resistivity (ρ = |Ex / Hy| 2 / ωμ), inversion of the underground electrical structure. In rare earth ore exploration has the following advantages: effective detection depth 50 ~ 1500 m, suitable for concealed ore body positioning; vertical resolution can reach 5 ~ 10 m, can identify thin layer of mineralization; artificial source signal overcomes the problem of random noise of natural field source (such as MT method).

[0104] 4.1) Instrument equipment:

[0105] CSAMT work using the instrument equipment for Canada Phoenix Company produced V8 multifunctional electrical workstation, the main instrument includes SGC-34 generator (1), TXU-30 transmitter (1), V8-6R multifunctional receiver (1), RXU-3ER auxiliary receiver (2), AMTC-30 high frequency magnetic bar (1).

[0106] 4.2) Instrument test:

[0107] In the field of measurement area site, the instrument host and acquisition box are calibrated, on the one hand to check the performance of the instrument, instrument (channel) consistency test, on the other hand, the calibration results are used to correct the collected data in real time, to ensure the authenticity and reliability of the data.

[0108] 4.3) Working device and parameter selection:

[0109] The equatorial dipole measurement device is used, the scalar measurement method and the TM measurement mode are used. Scalar CSAMT measurement uses one field source to measure two components (Ex and Hy). The schematic diagram of CSAMT observation device is shown in Figure 7 .

[0110] The transmission field is moved synchronously with the measuring line to ensure that the observation point is arranged in a trapezoidal area formed by a 60° angle of the transmission dipole. The upper base of the trapezoid is the position of the AB transmission dipole, and the AB pole line direction is parallel to the measuring line direction. In order to ensure the observation in the far field area, the receiver-transmitter distance R is greater than three times the skin depth in the relatively small human interference measurement area.

[0111] According to the requirements of the working detection depth and the electrical characteristics of the exploration area, the receiver-transmitter distance R is determined to be 11 km through test, which meets the requirement of more than 3 times the skin depth. The transmission power dipole distance AB is 1.5 km, which can suppress interference and meet the 60° angle control of the receiving range. According to the detection target, the receiving pole distance MN is 20 ~ 40 m, and the point distance is 20 ~ 40 m. The effective frequency range of collection is 8533 Hz ~ 0.125 Hz.

[0112] 4.4) Field data collection:

[0113] 4.4.1) Field source installation:

[0114] The power supply electrode AB is laid parallel to the survey line direction, with an azimuth error of less than 3°. It is laid in a place with solid and moist soil and good grounding conditions. Low voltage and high current are used for power supply to avoid electromagnetic interference such as high-voltage lines. After laying, check that the insulation resistance of the power supply wires is greater than 3MΩ / km.

[0115] 4.4.2) Receiving device installation:

[0116] The receiving wires were laid close to the ground, with non-polarized electrodes used for the M and N poles. They were buried in hard soil and watered to reduce ground resistance. Appropriate offsets were applied to areas with high electromagnetic interference.

[0117] The magnetic probe was positioned perpendicular to the receiving electrode MN, with an azimuth error of less than 2°. The magnetic probe was placed horizontally and close to the ground. The distance between the magnetic probe and the receiver was greater than 10 meters, away from interference sources such as high-voltage power lines, roads, and vehicles. During observations, all personnel and vehicles were kept away from the magnetic probe and all communication equipment was stopped.

[0118] 4.4.3) Data Collection:

[0119] Before data collection begins, the GPS of the receiver and transmitter are synchronized. At the same time, ensure that the receiving electrode is well grounded, the magnetic probe is working properly, and the point and line numbers are entered correctly.

[0120] During field observations, record any geological phenomena, topography, and noise sources near the observation point that may affect the observation results for use in data processing. After work, promptly transfer the collected data to the computer.

[0121] 4.5) Data processing and interpretation:

[0122] 4.5.1) Data processing:

[0123] CSAMT data processing can be divided into two parts: data preprocessing and data inversion. The preprocessing software used is CMT.PRO, developed by Phoenix, Canada. It primarily involves inputting measurement point coordinates, removing distorted points, and exporting text data. It also performs terrain correction, using DEM data for constraints to avoid false valley / ridge anomalies. Data inversion uses WINGLINK, developed by GEOSYSTEM, Italy. First, a one-dimensional Occam inversion is performed to quickly obtain an initial model. Then, a two-dimensional nonlinear conjugate gradient inversion is performed, incorporating geological mapping constraints to improve resolution. Finally, the inverted resistivity grid file is generated, and resistivity contour profiles are generated.

[0124] 4.5.2) Comprehensive interpretation:

[0125] Combined with regional geological features, the geological bodies are interpreted by using the resistivity contour profile. The key electrical indicators in the interpretation are low resistivity anomaly (<300 Ω·m), which may indicate sulfide associated rare earth mineralization (e.g. Baiyune'obo in Inner Mongolia); the relatively low resistivity band in the high resistivity background, which reflects alteration or fluid activity (e.g. Maoniuping in Sichuan); and the electrical gradient zone, which often corresponds to the mineralization boundary (e.g. the contact zone of rock mass). The typical electrical response characteristics of the rare earth ore geological body are shown in Table 3. When interpreting, the gamma ray spectrometry (Th / U anomaly) and XRF (La / Ce anomaly) data are superimposed, and the relationship between the spatial distribution of low resistivity body and alteration zone is analyzed.

[0126] Table 3 Typical electrical response characteristics of rare earth ore geological body

[0127]

[0128] In particular, the ore body is usually present in the fault structure, and the interpretation features of the fault are as follows:

[0129] (1) When the fault is located at the contact zone of two different rocks with different electrical characteristics, due to the difference in lithologic resistivity on both sides, it is often reflected as a directional deep low resistivity band or an isopleth step anomaly on the CSAMT apparent resistivity section.

[0130] (2) When the fault develops in the shallow surface, the continuity of the original rock is destroyed, which destroys the continuity and stability of the electromagnetic field, causing the potential field to be distorted. The apparent resistivity contour is usually disturbed, and the fault is usually reflected as a low resistivity "U" or "V" shaped anomaly.

[0131] (3) When the fault develops in the same lithologic layer, it is reflected as a wide and sparse isopleth interval on the apparent resistivity section, which is curved downward synchronously, locally forms a saddle, and has a string of bead-shaped anomaly characteristics.

[0132] Specifically, in this embodiment, the controlled source audio frequency magnetotelluric sounding (CSAMT) is used to control the presumed ore-controlling structure, the known ore body and the deep shape, occurrence and depth of the concealed ore body according to the rock resistivity characteristics (Table 4). The CSAMT scalar data are collected in the field, the data are preprocessed and inverted, the inverted resistivity section is obtained, and then the geological body contact relationship, structure and deep extension of the ore body are interpreted by corresponding to the geological profile. Since the ore body in the area is mostly present in the altered tectonic fracture zone, the CSAMT work is good for interpreting the deep extension of the ore body.

[0133] Table 4 Statistical table of rock resistivity parameters

[0134]

[0135] The instrument equipment used is V8 multifunctional electric method workstation produced by Phoenix Company of Canada. The main instruments include SGC-34 generator (1), TXU-30 transmitter (1), V8-6R multifunctional receiver (1), RXU-3ER auxiliary receiver (2), and AMTC-30 high-frequency magnetic bar (1). According to the Figures 8-11 It can be seen that the main machine and the acquisition box are calibrated in the field of the survey area. All the calibration results meet the standard theoretical curve. The amplitude and phase curve shape is smooth and regular in the working frequency band. The frequency response of the instrument is normal and stable.

[0136] After setting the parameters such as transmitting-receiving distance, power supply electrode distance, receiving electrode distance, point distance, and working frequency, the field source and receiving device are laid out in the field. The collected data is preprocessed and inverted by CMT.PRO software and WINGLINK software. Finally, the resistivity grid file after inversion is provided, and the resistivity contour profile is generated.

[0137] According to the geological characteristics and corresponding geological profile in the area, the contact relationship of geological bodies, structure, and deep extension of ore bodies are interpreted. Taking PT1 controlled source audio magnetotelluric sounding profile as an example, the strike of PT1 profile is NNE, the azimuth angle is 20º, and the length is 1120 m. It is preliminarily inferred that there are two faults (F1 and F2) in the area. Figure 12 Figure 13 F1 fault is located at the position of 400. It shows low resistance in the shallow part and deep part, which is speculated to be the reflection of broken and water-filled. The deep part shows the characteristics of dense stepped zone. There is a mineralized body outcrop in the F2 fault on the ground. F2 fault is located near the position of 900. The characteristics are similar to those of F1 fault. It shows low resistance in the shallow part and deep part, and the deep part also shows the characteristics of dense stepped zone. The two faults show symmetrical characteristics and form a funnel-shaped local low-value anomaly area in the deep part.

[0138] According to the geological data, it is inferred that the low-value area of apparent resistivity formed between F1 and F2 faults corresponds to the invasiveness of the nepheline monzonite porphyry affected by Mesozoic magmatic movement. The nepheline monzonite porphyry of Cuijiagou unit of late copper sequence along the fault invades the quartz monzonite porphyry of early copper sequence of Dongmashan unit with high resistivity, forming a local low-value anomaly area of apparent resistivity.

[0139] 5) Through 1) to 4), the key sections are verified by using trenching and drilling engineering methods for field systematic exploration, realizing the breakthrough in rare earth ore prospecting.

[0140] Specifically, the drilling engineering is carried out for field systematic exploration verification of the ore-controlling structure circled in 4). According to the occurrence and deep extension trend of the interpreted F2 ore-controlling structure, three drill holes are constructed for deep verification, which achieves good ore prospecting effect, controls the extension of ore body and ore-controlling structure, and realizes the breakthrough in rare earth ore prospecting.​

[0141] 6) Through 1) ~ 5), finally establish a set of regional geological characteristics and aerial radioactive anomaly characteristics based on the delineation and screening of ore-forming prospective area, large-scale detailed geological mapping and ground gamma-ray spectrometry preferred focusing on ore-prospecting target area, using portable XRF analyzer field detection delineation of ore-bearing geological body, electromagnetic inversion constrained ore body shape, anomaly verification and engineering verification, etc. Multi-level concealed ore body identification and verification of exploration technology system.

[0142] Embodiment two

[0143] As Figure 14 shown, the embodiment provides a hard rock type rare earth ore exploration system, comprising:

[0144] The data acquisition module 1401 is configured to acquire geological scientific data of a target area.

[0145] The ore-prospecting prospective area determination module 1402 is configured to delineate an ore-prospecting prospective area in the target area based on a regional ore-forming prediction model according to the geological scientific data of the target area.

[0146] The target area determination module 1403 is configured to perform large-scale geological mapping and ground gamma-ray spectrometry in the ore-prospecting prospective area, superimpose lithology-structure information, and screen out a high-value radioactive target area.

[0147] The ore-bearing geological body determination module 1404 is configured to deploy portable XRF detection in the high-value target area, and delineate an ore-bearing geological body based on semi-quantitative results of rare earth elements.

[0148] The inversion module 1405 is configured to perform CSAMT measurement on the ore-bearing geological body, determine low-resistance mineralization bodies and ore-controlling structures through electromagnetic data inversion.

[0149] The exploration module 1406 is configured to perform field system exploration by using trenching and drilling engineering means based on the low-resistance mineralization bodies and ore-controlling structures.

[0150] The ore-prospecting prospective area determination module 1402 comprises:

[0151] The ore-prospecting prospective area determination unit is configured to analyze regional fault zone features, regional magmatic rock activity, research alkali rock, carbonatite complex characteristics, and aerial gamma radiation measurement anomaly characteristics in the target area based on a regional ore-forming prediction model according to regional geology, regional mineral resources, geophysical, geochemical and remote sensing data, and obtain an ore-prospecting prospective area in the target area.

[0152] To sum up, the present application has the following technical effects:

[0153] The application establishes a multi-method collaborative exploration technical system for identifying and verifying multi-level concealed ore bodies, which comprises the following steps: a set of prospecting areas are delineated and screened based on regional geological characteristics and aerial radioactive anomaly characteristics; a target area is focused by large-scale detailed geological mapping and ground gamma-ray spectrometry; a geological body hosting ores is delineated by on-site detection using a portable XRF analyzer; an ore body shape is constrained by electromagnetic comprehensive inversion; and anomaly verification and engineering verification are performed. The technical system can effectively solve the problems of concealed mineralization markers, deep prediction difficulty and high cost in hard rock type rare earth ore exploration. Through a progressive exploration process of "regional screening-target area focusing-deep positioning-engineering verification", the exploration goal of "rapid positioning and accurate attack" of hard rock type rare earth ore is achieved, and the efficiency and accuracy of prospecting are significantly improved. The method has the advantages of environmental friendliness, accurate control, energy saving and economy.

[0154] The technical features of the above embodiments can be combined in any manner. To make the description concise, all possible combinations of the technical features in the above embodiments are not described, but as long as the combinations of the technical features do not contradict, they should be considered as falling within the scope of the present disclosure.

[0155] The principles and implementation modes of the present application are described by using specific examples. The above descriptions of the embodiments are only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, the specific implementation modes and application ranges can be changed according to the idea of the present application. In summary, the content of the present description should not be understood as a limitation of the present application.

Claims

1. A hard rock rare earth mineral exploration method, characterized in that: include: Acquiring geological science data of the target area; the geological science data includes regional geology, regional mineral resources, geophysics, geochemistry and remote sensing data; Based on the geological data of the target area and the regional metallogenic prediction model, the prospecting areas in the target area are delineated; According to the geological data of the target area and based on the regional metallogenic prediction model, the prospecting areas in the target area are delineated, including: Based on regional geological, regional mineral, geophysical, geochemical and remote sensing data and a regional mineralization prediction model, the regional fault zone characteristics, regional magmatic rock activity, alkaline rock and carbonatite complex characteristics, and airborne gamma radioactivity measurement anomaly characteristics of the target area are analyzed to obtain prospective mineralization areas in the target area; Conduct large-scale geological mapping and ground gamma ray spectrum measurement in prospecting areas, overlay lithology-structure information, and screen out high-radioactivity target areas; The ground gamma ray spectrum measurement specifically includes: Based on the large-scale geological mapping results, a set measurement grid is selected to conduct ground gamma spectroscopy measurements to delineate radioactive anomaly areas associated with rare earth minerals, the exact location of anomaly sources, and target geological bodies. The large-scale geological mapping specifically includes: using a tracing method and a crossing method to describe the surface geological characteristics of a set area, a set geological boundary, and a set geological body in the target area to obtain large-scale geological mapping results. The scale of the large-scale geological mapping is 1:10,000 to 1:2,000. The grid centerline spacing ranges from 20 to 250 meters, and the point spacing ranges from 5 to 50 meters. The following formulas are used to calculate the background value, standard deviation and coefficient of variation of the eU, eTh, K and Tc contents of the geological bodies in the survey area: ； ； ； In the formula, X is the background value, S is the standard deviation, C V is the coefficient of variation, X i is the content value of the element at the i-th measuring point, and n is the number of samples; Deploy portable XRF testing in the high-value target area to delineate the ore-bearing geological body based on the semi-quantitative results of rare earth elements; Portable XRF testing was deployed in the high-value target area to identify the ore-bearing geological bodies based on the semi-quantitative results of rare earth elements, including: A portable XRF analyzer is used in high-value target areas to quickly identify and semi-quantitatively detect rare earth elements, and the ore bodies distributed inside and around the magmatic rock body are obtained; Based on the semi-quantitative results of rare earth elements and the geological background, the distribution characteristics of rare earth elements in the high-value target area are analyzed to determine the specific location and scope of the ore-bearing geological body; Carry out CSAMT survey on the ore-bearing geological body and identify the low-resistivity mineralized body and ore-controlling structure through electromagnetic data inversion; CSAMT measures the surface electric and magnetic field components by artificially emitting audio-frequency electromagnetic signals. It then calculates the Carnia resistivity and inverts the underground electrical structure using the formula ρ=|Ex / Hy|² / ωμ; Ex is the surface electric field and Hy is the magnetic field. Based on low-resistivity mineralized bodies and ore-controlling structures, field systematic exploration is carried out using trenching and drilling engineering methods.

2. A hard rock rare earth ore exploration system for implementing the hard rock rare earth ore exploration method according to claim 1, characterized in that: include: Data acquisition module, used to obtain geological science data of the target area; The prospecting area determination module is used to delineate the prospecting area in the target area based on the geological science data of the target area and the regional metallogenic prediction model; The prospecting prospect area determination module includes: The prospecting area determination unit is used to analyze the regional fault zone characteristics, regional magmatic rock activity, alkaline rock, carbonatite complex characteristics and airborne gamma radioactivity measurement anomaly characteristics of the target area based on regional geological, regional mineral, geophysical, geochemical and remote sensing data and the regional metallogenic prediction model, and to determine the prospecting area in the target area; The target area determination module is used to conduct large-scale geological mapping and ground gamma ray spectrum measurement in prospecting areas, superimpose lithologic and structural information, and screen out high-radioactivity target areas; The ore-bearing geological body determination module is used to deploy portable XRF detection in the high-value target area and delineate the ore-bearing geological body based on the semi-quantitative results of rare earth elements; The inversion module is used to perform CSAMT surveys on ore-bearing geological bodies and determine low-resistivity mineralized bodies and ore-controlling structures through electromagnetic data inversion; The exploration module is used to conduct field systematic exploration based on low-resistivity mineralized bodies and ore-controlling structures using trenching and drilling engineering methods.

Images