A pegmatite rare metal ore exploration method in high-cold and high-altitude areas

Abstract

This invention discloses a method for exploring rare metal deposits in pegmatites in high-altitude and cold regions, comprising: acquiring data on high-altitude and cold regions; using the acquired data to explore the ore-bearing strata, ore-controlling structures, distribution patterns of pegmatite veins, and the distribution range of ore-bearing and ore-free pegmatites within the mining area; based on the exploration results, comprehensively delineating surface ore-bearing geological bodies using remote sensing geological interpretation, geological mapping, and geochemical methods, and determining the spatial distribution morphology of ore-bearing geological bodies at depth using geophysical measurement methods; conducting deep verification using drilling methods; establishing a prospecting model based on the acquired data and exploration results; and combining the prospecting model to extract indicator information of favorable mineralization areas in the region and delineating prospecting target areas. This invention, by combining remote sensing geological interpretation, geological mapping, geochemical methods, and geophysical measurement methods, can accurately obtain the location information of rare metal deposits in pegmatites.

Description

Technical Field

[0001] This invention relates to the field of mineral exploration technology, and in particular to a method for exploring rare metal deposits in pegmatites in high-altitude and cold regions. Background Technology

[0002] Currently, the exploration of rare metal deposits in pegmatites in high-altitude and cold regions faces numerous challenges. These areas have complex terrain and harsh climates, making it difficult to conduct efficient operations and achieve rapid mineral discovery using conventional exploration methods. Traditional exploration methods often rely solely on geological surveying or geophysical and geochemical exploration, failing to simultaneously delineate surface ore-bearing geological bodies and detect deep spatial distribution, resulting in low exploration accuracy. Summary of the Invention

[0003] The purpose of this invention is to provide a method for exploring rare metal deposits in pegmatites in high-altitude and cold regions, in order to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides a method for exploring rare metal deposits in pegmatites in high-altitude and cold regions, comprising the following steps: S1. Obtain regional geological, geophysical and geochemical, and remote sensing data and mineral information for high-altitude and cold regions, and analyze the distribution patterns, ore-controlling factors, and physical characteristics of different geological bodies in dense pegmatite areas. S2. Using the acquired data, investigate the ore-bearing strata, ore-controlling structures, distribution patterns of pegmatite veins, and distribution range of ore-bearing and ore-free pegmatites in the mining area of ​​this high-altitude and cold region. S3. Based on the exploration results, remote sensing geological interpretation, geological mapping and geochemical methods are used to delineate the surface mineral-bearing geological bodies. Geophysical measurement methods are used to determine the spatial distribution of the mineral-bearing geological bodies in the deep part. Geophysical measurement methods include physical property sample measurement, audio-frequency magnetotelluric measurement (AMT) and gravity profile measurement. S4. Conduct deep drilling verification based on the above results; S5. Establish a mineral exploration model based on the acquired data and exploration results; S6. Conduct high-precision remote sensing geological interpretation and alteration information extraction at medium to small scales in this high-altitude and cold region. Combined with the mineral exploration model, extract the indicator information of favorable mineralization areas in the region and delineate the mineral exploration target area.

[0005] Preferably, in step S2, geological surveying methods are used to explore the ore-bearing strata, ore-controlling structures, distribution patterns of pegmatite veins, and distribution range of ore-bearing and ore-free pegmatites in the high-altitude and cold region. Specifically, a 1:10,000 geological surveying method is used to explore the mining area in the high-altitude and cold region. Mapping is mainly done by crossing the traverse method, supplemented by the tracing method for route geological observation. The mapping route is laid out at 150-meter intervals, and geological points are set at the contact points of different strata, structures, and pegmatite veins. A 1:2,000 geological surveying method is used to explore the vein groups in the mining area. Mapping is mainly done by the tracing method, supplemented by the crossing method. Geological points are set at the boundaries of the mapping unit, marker layers, ore body boundaries, and locations with representative occurrence elements.

[0006] Preferably, the geochemical measurement method in step S3 specifically includes: Based on the production practices in this high-altitude and cold region, the actual situation in the area, and the topographic and geological conditions, a stream sediment measurement was conducted in the mining area. The sample size ranged from -10 to +80 mesh, and the sampling density was 8 to 10 points per square kilometer. Based on the comprehensive geochemical anomaly enrichment characteristics of the mining area, combined with the results of spectral analysis and complete rock and mineral analysis, and considering the metallogenic geological conditions of the mining area, the elements selected for geochemical analysis were determined. Sampling points were set up in the primary, secondary and tertiary water systems, and multiple sampling points were combined into one sample. A clear map of the sampling point locations was drawn. Geochemical maps were drawn based on the sampling results.

[0007] Preferably, the remote sensing geological interpretation in step S3 includes: Remote sensing data corresponding to mining areas in high-altitude and cold regions are acquired, and the remote sensing data are preprocessed. The preprocessing includes geometric correction, radiometric correction, radiometric calibration, atmospheric correction, spatial resolution unification, and background information removal. Based on the principle of selecting bands with the largest possible variance in band radiance and the smallest possible correlation between bands, we selected a combination of bands from the remote sensing data that could highlight the differences between different lithologies. Based on the spectral characteristics of pegmatite, the bands in the band combination were screened to obtain the final bands; Principal component analysis was used to analyze the data in the final band, and an alteration information extraction model was constructed based on the analyzed data. The alteration of pegmatite was then extracted based on the alteration information extraction model.

[0008] Preferably, the gravity measurement method in step S3 includes: A total gravity baseline and gravity measuring points are set up in the mining area. The gravity value of the measuring point is the relative gravity value relative to the total baseline. The gravity of the measuring point is observed using the single-pass observation method. Gravity values ​​are calculated based on gravity observation data from measuring points. The calculations include corrections for normal field, height, Bouguer, topography, and solid tides. Topography corrections are applied to near, middle, and far-field regions. Near-field corrections are calculated using a cone formula, while middle and far-field corrections are calculated using a square domain method. The topography correction values ​​are obtained using the formula... 远 Calculate, where, , , , These represent the topographic correction values, near-field topographic correction values, mid-field topographic correction values, and far-field topographic correction values, respectively. The gravity calculation results are quality checked, and the accuracy is measured by the mean square error.

[0009] Preferably, the audio magnetotelluric method in step S3 includes: Acquire magnetotelluric sounding data within the mining area and preprocess the data, including editing, smoothing, and static correction; One-dimensional continuous medium inversion was performed on the preprocessed data to obtain sounding curves, apparent resistivity profiles, and phase profiles. Based on the one-dimensional continuous medium inversion results, a two-dimensional continuous medium inversion is performed; Geoelectric models are established based on the inversion structures of one-dimensional and two-dimensional continuous media. Geological interpretation is then performed based on the geoelectric models to obtain apparent resistivity and phase.

[0010] Preferably, in step S4, a mineral exploration model is established based on the DSI spatial interpolation algorithm.

[0011] Preferably, the prospecting model includes a three-dimensional surface and borehole model, a three-dimensional stratigraphic model, a three-dimensional geological body model, and a three-dimensional physical model, wherein the three-dimensional physical model includes a gravity model and an AMT model.

[0012] Therefore, the present invention adopts the above-mentioned method for exploring rare metal deposits in pegmatites in high-altitude and cold regions. By combining remote sensing geological interpretation, geological mapping, geochemical methods and geophysical measurement methods, the location information of rare metal deposits in pegmatites can be accurately obtained.

[0013] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0014] Figure 1 This is a flowchart of a method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a three-dimensional surface and borehole model according to an embodiment of the present invention, wherein (a) is a three-dimensional surface model and (b) is a borehole model; Figure 3 This is a schematic diagram of a three-dimensional stratigraphic model according to an embodiment of the present invention, wherein (a) is a model of the upper section of the middle formation of the mountain group, and (b) is a model of the lower section of the upper formation of the mountain group; Figure 4 This is a schematic diagram of a three-dimensional geological body model according to an embodiment of the present invention, wherein (a) is a model of intermediate-acidic intrusive rocks and granite pegmatite, (b) is a model of dioxane-monzogranite, (c) is a geological body location model, and (d) is a geological body model; Figure 5 This is a schematic diagram of a three-dimensional geophysical model according to an embodiment of the present invention, wherein (a) is the N-direction gravity anomaly model, (b) is the N-direction AMT model, (c) is the S-direction gravity anomaly model, and (d) is the S-direction AMT model. Figure 6 This is a schematic diagram of mineral exploration target area prediction according to an embodiment of the present invention, wherein (a) is a mineral exploration target area location model and (b) is a mineral exploration target area model. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can be arranged and designed in various different configurations, and therefore should not be construed as limiting the present invention.

[0016] Example like Figure 1 As shown, this invention provides a method for exploring rare metal deposits in pegmatites in high-altitude and cold regions. Taking a high-altitude and cold hard rock lithium-beryllium deposit as the research object, and targeting the key metallogenic geological bodies and structures in the 509 Road Maintenance Station West Mining Area, the method includes the following steps: S1. Obtain regional geological, geophysical and geochemical, and remote sensing data and mineral information for high-altitude and cold regions, and analyze the distribution patterns of dense pegmatite areas, ore-controlling factors, and physical characteristics of different geological bodies.

[0017] S2. Based on the full utilization of existing geological data, geological surveying methods were used to explore the ore-bearing strata, ore-controlling structures, distribution patterns of pegmatite veins, and distribution range of ore-bearing and ore-free pegmatites in the 509 Road Maintenance Station West Mining Area of ​​this high-altitude and cold region.

[0018] Specifically, the 1:10000 geological survey method was used to explore the western mining area of ​​the 509 Road Maintenance Station.

[0019] Mapping primarily employs the traversal method supplemented by the tracing method for geological observation along the route. Mapping routes are laid out at 150-meter intervals, with geological points located at the contact points of different strata, structural features, and pegmatite dikes, effectively controlling various stratigraphic boundaries and geological elements. Geological point records are continuous observation records, accurately and objectively reflecting the characteristics of geological bodies.

[0020] The 1:2000 geological survey method was used to explore vein groups I-IV within the mining area. Before geological mapping, a geological profile was first constructed. The profile location was selected in an area with a relatively complete stratigraphic sequence, simple structure, clear contact relationships, and good bedrock exposure. The profile azimuth was 216°, basically perpendicular to the strike of the strata, and the profile scale was 1:1000. During the profile measurement process, the material composition, structure, texture, deformation and metamorphic characteristics of the rocks (ores) needed to be observed and recorded in detail. Thin sections and bedrock spectral samples needed to be collected. Based on this, mapping units were divided.

[0021] Mapping primarily employs the tracing method, supplemented by the traversal method. During the work, in addition to arranging tracing or traversal geological routes in the main lithium-beryllium orebody distribution areas, detailed observation of existing trenching and artificial outcrops formed by road construction is required. The focus is on studying the characteristics of surface lithium-beryllium ore bodies, strata, structures, and dikes. Geological points are placed at the boundaries of the mapping unit, marker layers, orebody boundaries, and locations with representative occurrence elements. During the mapping process, all ore bodies with a width ≥1 meter and an extension ≥3 meters must be represented on the map. RTK measurements are used to locate orebody boundaries, engineering points, and various geological points.

[0022] S3. Based on the exploration results, remote sensing geological interpretation, geological mapping, and geochemical methods are used to comprehensively delineate the surface ore-bearing geological bodies. Geophysical measurement methods are used to determine the spatial distribution of the ore-bearing geological bodies at depth. Geophysical measurement methods include physical property sample measurement, audio-frequency magnetotelluric (AMT) measurement, and gravity profile measurement. Among them, gravity profiles are arranged on four exploration lines: 0, 7, 8, and 19, and audio-frequency magnetotelluric (AMT) profiles are arranged on nine exploration line profiles: 0, 7, 8, 19, 31, 39, 47, 51, and 59.

[0023] Geochemical methods include: Based on the production practices in this high-altitude and cold region, the actual situation in the area, and the topographic and geological conditions, a 1:25000 scale stream sediment survey was conducted in the mining area, with a sampling particle size of -10 to +80 mesh and a sampling density of 8 to 10 points per square kilometer.

[0024] Based on the comprehensive anomaly element enrichment characteristics of the 1:250,000 geochemical exploration in the mining area, combined with the results of spectral analysis and complete rock and mineral analysis, and considering the metallogenic geological conditions of the mining area, the selected analysis items for the 1:250,000 geochemical exploration in the mining area were determined. The selected elements include Li, Be, Rb, Cs, Nb, Ta, W, Sn, Ag, Pb, etc.

[0025] Sampling points were set up in the primary, secondary and tertiary water systems. A small number of sampling points were set up in the tertiary water system, and multiple sampling points (3-5 points) were combined into one sample. A clear map of the sampling points was drawn. Geochemical maps were created based on the sampling results. The geochemical maps use seven primary colors to increase the layers of the map and show the concentration trends of elements.

[0026] Remote sensing geological interpretation includes: WorldView-3 (WV-3) (16-band) remote sensing data corresponding to the mining area was acquired and preprocessed. WV-3 includes one panchromatic band (spatial resolution of 0.31m), eight visible-near-infrared bands (spatial resolution of 1.24m), and eight shortwave infrared bands (spatial resolution of 3.7m). WorldView-3 is a sun-synchronous near-polar orbit at an altitude of 617km and a revisit period of 97min. The WorldView-3 data used for the mining area was received at 5:34:36.7 AM GMT on August 31, 2023, with a solar azimuth of 145.500000°, a solar altitude of 58.800000°, a UTM projection coordinate system, Zone 44N, and a WGS-84 projection ellipsoid.

[0027] Preprocessing includes geometric correction, radiometric correction, radiometric calibration, atmospheric correction, spatial resolution unification, and background information removal. Specifically, the mining area is composed of two images. Using ENVI's seamless mosaic technology, the two image data are stitched together into a single image file. Finally, the shortwave infrared band and the visible and near-infrared bands are combined to form a 16-band remote sensing image with unified spatial resolution. Background information removal uses a band ratio method (band7 / band10) to create a mask to remove interference from ice and snow. Using (band2 / band14) > 1 as a criterion, images of shadowed areas and water bodies are eliminated.

[0028] Following the principles of maximizing the variance of band radiance and minimizing inter-band correlation, band combinations from remote sensing data that highlight differences between different lithologies were selected. The WorldView-3 data's R (band 8), G (band 9), and B (band 13) band combination contains the richest information and effectively highlights these differences. By establishing markers such as stratigraphy, intrusive rocks, and structures, remote sensing anomalies can be effectively delineated.

[0029] Remote sensing data revealed that the spectra of spodumene granite pegmatites exhibit high reflectance, with prominent H₂O absorption peaks at 1400 nm and 1900 nm, generally deeper than those of mineral-free granite pegmatites. Secondly, they possess a strong Al-OH absorption peak at 2197 nm, with a sharp peak shape and significant depth, clearly distinct from mineral-free pegmatites and intrusive bodies. Some samples show absorption peaks at 2340 nm, where Mg-OH and -OH absorption peaks are observed; this characteristic is also present in mineral-bearing pegmatites found in lithium deposits of the Huangyangling Group and Bayan Harshan Group.

[0030] Based on the spectral characteristics of pegmatite, the bands in the band combination were screened, and the VNIR-1, VNIR-7, SWIR-3, and SWIR-6 bands were selected.

[0031] Principal component analysis (PCA) was used to analyze the data within the final bands, and an alteration information extraction model was constructed based on the analyzed data. The alteration of pegmatite was then extracted using this model. Specifically, based on the spectral characteristics of altered minerals in spodumene-bearing granite pegmatite, these minerals exhibit absorption characteristics in the VNIR-7 and SWIR-6 bands, while showing reflection characteristics in the SWIR-3 band. Therefore, after PCA, the contribution coefficients of the VNIR-7, SWIR-6, and SWIR-3 bands in the principal component eigenvector matrix of this type of alteration should have different signs. Thus, three remote sensing anomalies were delineated when extracting this type of alteration.

[0032] Physical property measurements of specimens include: Physical property specimens are collected from trenches and borehole cores, covering the main lithologies in the area. Typically, 2-3 specimens are collected from each site, taken from fresh rock, with a weight of approximately 500 grams and dimensions ≥ 6×6×6 cm.

[0033] The magnetic susceptibility, resistivity, polarizability, and density parameters of rock and ore samples were measured.

[0034] Gravity measurement methods include: A general gravity baseline and gravity measuring points were established within the mining area. For the large-scale gravity measurement of the mining area, given its small area, a relative gravity measurement method was adopted. A general gravity baseline, designated G-1, was established in the mining area, with measured coordinates of x=39615915.917; y=3967674.591; h=4743.539. The gravity values ​​at the measuring points were relative to the general gravity baseline. Gravity observations at the measuring points were conducted using a single-pass observation method, with observation intervals greater than 5 minutes.

[0035] The gravity values ​​are calculated based on gravity observation data to obtain gravity calculation results. The calculations include normal field correction, height correction, Bouguer correction, topographic correction, and solid tide correction.

[0036] Normal field correction: Convert the measured kilometer grid coordinates to latitude and longitude, and calculate the gravity value on the geoid using the normal gravity formula in the geodetic reference system recommended by the International Union of Geodesy: ; In the formula, Indicates the latitude of the gravity measurement point. This represents the normal gravity value, in units of 10. -5 m / s 2 .

[0037] The height correction formula is: ; In the formula, Indicates the elevation of the gravity measuring point. This represents the height correction value of the gravity measuring point, in units of 10. - 5 m / s 2 .

[0038] Bouguer correction formula is: ; In the formula, This represents the corrected radius of the intermediate circular region, in meters (m). This represents the density value of the intermediate layer, in units of 10. 3 kg / m 3 , This indicates the elevation of the gravity measuring point (a negative value is given when the measuring point is below the elevation datum), and the unit is meters (m).

[0039] The Bouguer gravity anomaly formula is: ; In the formula, This represents the Bouguer gravity anomaly. The value of gravity at the measuring point. This indicates the normal gravity value. This is the Bouguer correction value; These are terrain correction values, all in units of 10. -5 m / s 2 .

[0040] Topographic correction includes corrections for near, middle, and far zones. The near zone correction radius is 0-20 meters, calculated using a cone formula, as follows: ; In the formula, The gravitational constant is (6.67 × 10⁻⁶). -11 m 3 / (kg·S 2 )); Topographic correction density, in units of 10. 3 kg / m 3 ; Let the radius of the circular region be the terrain correction radius (m). The slope angle of the terrain; The corrected azimuth number for the terrain is the number of small cones into which the near-ground terrain is divided with O as the vertex.

[0041] The land reform radius for the central area is 20-2000 meters, and the land reform radius for the far area is 2-20 kilometers. The corrections for the central and far areas are calculated using the square domain calculation method.

[0042] Terrain correction values ​​are calculated using a formula. 远 Calculate, where, , , , 远 These represent the topographic correction values ​​for the near-field, mid-field, and far-field areas, respectively, all in units of 10. -5 m / s 2 .

[0043] The quality of the corrected gravity calculation results is checked, and the accuracy is measured by the mean square error.

[0044] Audio magnetotelluric methods include: First, the deployment was carried out, including station setup, conductor laying, electrode grounding, leakage current inspection, and station observation. During deployment, four sets of V8 magnetotelluric sounding instruments were used (two sets of V8-6 main stations, two sets of RUX-3ER auxiliary stations, and four audio probes), operating at frequencies from 0.35Hz to 10400Hz.

[0045] Secondly, magnetotelluric sounding data within the mining area are obtained based on the deployed stations, and the data is preprocessed, including editing, smoothing, and static correction. The data acquisition time at each station is generally 90 minutes.

[0046] One-dimensional continuous medium inversion was performed on the preprocessed data to obtain sounding curves, apparent resistivity profiles, and phase profiles.

[0047] Based on the inversion results of one-dimensional continuous media, a two-dimensional continuous media inversion is performed.

[0048] Geoelectric models are established based on the inversion structures of one-dimensional and two-dimensional continuous media. Geological interpretation is then performed based on the geoelectric models to obtain apparent resistivity and phase.

[0049] S4. Conduct deep verification using drilling methods.

[0050] S5. Establish a mineral exploration model based on the acquired data and exploration results. Specifically, based on data such as satellite remote sensing images of the mining area, 1:25,000 geochemical anomaly maps, 1:10,000 geological maps, 1:2,000 geological maps, gravity measurement maps, and AMT audio-visual magnetotelluric profiles, a mineral exploration model is established using SUKA-GOCAD software based on the DSI spatial interpolation algorithm. This model includes a three-dimensional surface and borehole model, a three-dimensional stratigraphic model, a three-dimensional geological body model, and a three-dimensional physical model. The three-dimensional physical model includes a gravity model and an AMT model.

[0051] like Figure 2 The image shown is a schematic diagram of the three-dimensional surface and borehole model of the West Lithium Mine Area of ​​Road Maintenance Station 509. The three-dimensional surface is as follows: Figure 2 As shown in (a) above, the borehole model is as follows: Figure 2 As shown in (b) of the figure, 1 represents elevation; 2 represents the exploration line profile; 3 represents the mining area; and 4 represents boreholes. The exploration lines and model show that the mining area is located in a high-mountain to extremely high-mountain terrain, with an elevation ranging from 5550 to 4650 meters and a relative elevation difference of approximately 300 to 1200 meters. The overall terrain slopes from south to north and from west to east. The main ore body is located on the southern slope, with 25 exploration lines laid out from west to east, from line 59 to line 16. Among these, lines 39 to 15 were used for denser control of the thicker ore bodies. A total of 143 boreholes were drilled along these exploration lines, with depths ranging from 80.07 to 583.5 meters and an average depth of 238.29 meters, essentially achieving control over the shallow main ore bodies in the mining area.

[0052] like Figure 3 The image shows a schematic diagram of a three-dimensional stratigraphic model of the Xili mining area at the 509 Road Maintenance Station. Geological mapping and borehole drilling reveal that the strata within the mining area are primarily composed of the Triassic Bayan Har Mountains Group and Quaternary strata. This mountain group is further divided into the upper section of the middle formation and the lower section of the upper formation. The upper section of the middle formation is shown below. Figure 3 As shown in (a) above, the lower segment of the upper group is as follows: Figure 3As shown in (b) of the diagram. The upper section of the middle group is mainly distributed in the south-central part of the mining area, and is the main rare metal ore-bearing stratum in the area. It is about 1 km thick and extends in a northwest-southeast direction. It has an intrusive contact with the Late Triassic diorite-monzogranite body in the south and a conformable contact with the lower section of the upper group in the north. It is mainly divided into three lithological assemblages: the southern lithological assemblage is composed of gray-grayish-brown medium-thick layered metamorphic fine-grained feldspathic sandstone interbedded with metamorphic siltstone; the central lithological assemblage is composed of diopside hornfels interbedded with metamorphic fine-grained feldspathic sandstone; and the northern lithological assemblage is composed of grayish-brown medium-thick layered metamorphic fine-grained feldspathic sandstone and grayish-black thin layered metamorphic siltstone interbedded. More than 95% of the lithium ore bodies are distributed in this lithological section. The lower section of the upper group is mainly distributed in the north-central part of the mining area, and is the secondary rare metal ore-bearing stratum in the area. It is about 3.5 km thick. The rock formation extends in a northwest-southeast direction, and its main lithology consists of grayish-brown medium- to thick-bedded fine-grained feldspathic quartz sandstone interbedded with grayish-black thin-bedded siltstone and argillaceous siltstone. In the figure, 1 represents the Quaternary system; 2 represents the upper section of the middle formation of the Shanshan Group, consisting of metamorphic feldspathic sandstone interbedded with metamorphic siltstone; 3 represents the upper section of the middle formation of the Shanshan Group, consisting of diopside hornfels interbedded with metamorphic feldspathic sandstone; 4 represents the upper section of the middle formation of the Shanshan Group, consisting of alternating layers of metamorphic feldspathic sandstone and metamorphic siltstone; 5 represents the lower section of the upper formation of the Shanshan Group, consisting of feldspathic quartz sandstone interbedded with siltstone; 6 represents dioxane granite; 7 represents granite pegmatite; 8 represents the ore body; and 9 represents a secondary fault.

[0053] like Figure 4 The image shows a schematic diagram of a three-dimensional geological model of the Xili mining area at 509 Road Maintenance Station. In the diagram, 1 represents elevation; 2 represents dioxane granite; 3 represents granite pegmatite; and 4 represents the ore body and its number. The mining area mainly consists of Late Triassic intermediate-acidic intrusive rocks and granite pegmatite, such as... Figure 4 As shown in (a) of the diagram. Distributed in the southwestern part of the mining area, with an exposed area of ​​approximately 7.5 square kilometers. The rock mass extends in a northwest-southeast trending band, with its long axis aligned with the main tectonic line. The rock mass boundaries are relatively flat, and the lithology is mainly medium- to fine-grained mica-monzogranite and granite pegmatite. It intrudes into the upper part of the middle section of the Triassic Bayan Har Mountains Group, with an irregular contact boundary, mostly dipping northeast. The granite pegmatite is distributed within a 400-meter radius of the northeastern outer contact zone of the mica-monzogranite, extending in a northwest-southeast trend. It consists of large veins occurring in vein-like patterns.

[0054] A total of 130 ore bodies were delineated within the mining area, mainly located in the upper part of the middle formation, within 600-1500 meters of the outer contact zone of the monzogranite. Figure 4 As shown in (b) and (c), the modeling was only carried out for the eight main ore bodies: No. 11, 12, 14, 17, 8, 45, 50, and 52. Figure 4As shown in (d), ore body No. 12 is located between exploration lines 16 and 59, and is vein-like. It is stratiform. The controlling ore body is 3040 meters long and 5.32–18.37 meters thick, making it the largest ore body in the area. The ore body is partially exposed at the surface, but mostly concealed. Its morphology is stratiform and vein-like, with stable extension, generally trending northwest to southeast, with an average strike of 127° and an average dip of 35°. Ore body No. 11 is located between exploration lines 8 and 59, and is partially exposed at the surface, second in size only to ore body No. 12. The controlling ore body is 2880 meters long and 3.73–24.55 meters thick, trending northwest to southeast, with an average strike of 123° and an average dip of 35°. Ore body No. 14 is located along exploration lines 21–59, with localized surface exposure. It is 1560 meters long, 3.15–17.74 meters thick, with an average strike of 127°, dipping northeast at angles of 16–50°. Ore body No. 17 is located along exploration lines 19–39, with localized surface exposure. It is 1080 meters long, 2.23–9.69 meters thick, with an average strike of 128°, dipping northeast at angles of 16–44°. The remaining ore bodies No. 8, 45, 50, and 52 occur as veins, with controlled dip lengths between 480 and 960 meters, average thicknesses between 3.35 and 7.31 meters, average strikes between 123 and 125°, and average dip angles between 27 and 35°.

[0055] like Figure 5 The figure shows a schematic diagram of a three-dimensional geophysical model of the Xili mining area of ​​the 509 Road Maintenance Station. In the figure, 1 represents gravity and electrical anomalies; 2 represents the ore body. The gravity anomaly in the mining area generally exhibits a sloping characteristic, lower in the south and higher in the north. A gentle local gravity height is observed in the central part of the mining area. This local gravity height is mainly caused by lithium-bearing spodumene granite pegmatite, with an anomaly amplitude ranging from 0.1 to 0.5 × 10⁻⁶. -5 m / s 2 ,like Figure 5 As shown in (a) and (c) in the figure. Audio-frequency magnetotelluric (AMT) sounding is a geophysical exploration technique that uses natural alternating electromagnetic fields to detect geoelectric properties and anomaly distribution characteristics. It can quickly and accurately reflect the underground electrical structure characteristics that change with depth. From the model, the Triassic Bayan Har Mountains Group strata in the mining area correspond to a layered low-resistivity anomaly of 20–300 Ω·m, while the spodumene-bearing granite pegmatite corresponds to a layered medium-high resistivity anomaly of 800–3000 Ω·m. Granite, ore-free granite pegmatite, and diopside-altered hornfelsized silicified sandstone correspond to a massive high-resistivity anomaly of 3000–10000 Ω·m. Using AMT sounding to delineate medium-high resistivity and high-resistivity anomalies can effectively trace the depth of the ore zone, such as... Figure 5 As shown in (b)(d) in the text.

[0056] S6. Conduct high-precision remote sensing geological interpretation and alteration information extraction at medium to small scales in this high-altitude and cold region. Combined with the mineral exploration model, extract the indicator information of favorable mineralization areas in the region and delineate the mineral exploration target area.

[0057] Based on the results of three-dimensional geological and geophysical models, the density of spodumene-bearing granite pegmatite ranges from 2.62 to 3.05 × 10⁻⁶. -3 Kg / m 3 The resistivity ranges from 800 to 3000 Ω·m, exhibiting localized high gravity and medium-to-high resistivity anomalies. The density of the metamorphic sandstone and siltstone of the Bayan Har Mountains Group is between 2.45 and 2.46 kg / m³. 3 It exhibits low gravity anomaly characteristics, but the density of the diopside hornfels or silicified sandstone is increased, ranging from 2.75 to 2.76 × 10⁻⁶. -3 Kg / m 3 The density of the ore body is similar to that of the spodumene-bearing pegmatite, which causes some interference. However, the resistivity of all strata is around 20–300 Ω·m, indicating a low-resistivity anomaly, which is significantly different from the characteristics of the ore body. The gravity characteristics of the ore-free granite pegmatite and quartz diorite are similar to those of the spodumene-bearing pegmatite, indicating a medium-to-high gravity anomaly, but their resistivity is much higher, ranging from 3000 to 100000 Ω·m, which is a high-resistivity anomaly, and shows certain characteristics different from the spodumene-bearing pegmatite. Analysis suggests that in this mountain group, the resistivity of the ore body extending deeper is between 800 and 3000 Ω·m, and the density is between 2.62 and 3.05 × 10⁻⁶. -3 Kg / m 3 The area with medium to high resistivity and localized high gravity anomalies was designated as a prospecting target area. Based on these characteristics, a relatively favorable prospecting target area was delineated in the deep eastern part of the mining area, such as... Figure 6 As shown in (a) and (b), the surface is located at exploration lines 27–55, with a deep elevation of 4430–4950 m, a width of 60–120 m, and an east-west extension of approximately 1200 m. The predicted scientific research resource volume is 150,000 tons. Figure 6 In the diagram, 1 represents the Quaternary system; 2 represents the upper section of the middle formation of the Shanshan Group, consisting of alternating feldspar sandstone and alternating siltstone; 3 represents the upper section of the middle formation of the Shanshan Group, consisting of diopside hornfels interbedded with alternating feldspar sandstone; 4 represents the upper section of the middle formation of the Shanshan Group, consisting of alternating layers of alternating feldspar sandstone and alternating siltstone; 5 represents the lower section of the upper formation of the Shanshan Group, consisting of feldspar quartz sandstone interbedded with siltstone; 6 represents the dioxane granite; 7 represents the granite pegmatite; 8 represents the apparent resistivity value; 9 represents the ore body; and 10 represents the prospecting target area.

[0058] Therefore, the present invention adopts the above-mentioned method for exploring rare metal deposits in pegmatite in high-altitude and cold regions, thereby improving the exploration accuracy of rare metal deposits in pegmatite.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for exploring rare metal deposits in pegmatites in high-altitude and cold regions, characterized in that, Includes the following steps: S1. Obtain regional geological, geophysical and geochemical, and remote sensing data and mineral information for high-altitude and cold regions, and analyze the distribution patterns, ore-controlling factors, and physical characteristics of different geological bodies in dense pegmatite areas. S2. Using the acquired data, investigate the ore-bearing strata, ore-controlling structures, distribution patterns of pegmatite veins, and distribution range of ore-bearing and ore-free pegmatites in the mining area of ​​this high-altitude and cold region. S3. Based on the exploration results, remote sensing geological interpretation, geological mapping and geochemical methods are used to delineate the surface mineral-bearing geological bodies. Geophysical measurement methods are used to determine the spatial distribution of the mineral-bearing geological bodies in the deep part. Geophysical measurement methods include physical property sample measurement, audio-frequency magnetotelluric measurement (AMT) and gravity profile measurement. S4. Conduct deep verification using drilling methods; S5. Establish a mineral exploration model based on the acquired data and exploration results; S6. Conduct high-precision remote sensing geological interpretation and alteration information extraction at medium to small scales in this high-altitude and cold region. Combined with the mineral exploration model, extract the indicator information of favorable mineralization areas in the region and delineate the mineral exploration target area.

2. The method for exploring rare metal deposits in pegmatites in high-altitude and cold regions according to claim 1, characterized in that: In step S2, geological surveying methods are used to explore the ore-bearing strata, ore-controlling structures, distribution patterns of pegmatite veins, and the distribution range of ore-bearing and ore-free pegmatites in the high-altitude and cold region. Specifically, a 1:10,000 geological surveying method is used to explore the mining area in this high-altitude and cold region. Mapping is mainly done by crossing the traverse method, supplemented by the tracing method for route geological observation. The mapping route is laid out at 150-meter intervals, and geological points are set at the contact points of different strata, structures, and pegmatite veins. A 1:2,000 geological surveying method is used to explore the vein groups in the mining area. Mapping is mainly done by the tracing method, supplemented by the crossing method. Geological points are set at the boundaries of the mapping units, marker layers, ore body boundaries, and locations with representative occurrence elements.

3. The method for exploring rare metal deposits in pegmatites in high-altitude and cold regions according to claim 1, characterized in that, The geochemical measurement methods in step S3 specifically include: Based on the production practices in this high-altitude and cold region, the actual situation in the area, and the topographic and geological conditions, a stream sediment measurement was conducted in the mining area. The sample size ranged from -10 to +80 mesh, and the sampling density was 8 to 10 points per square kilometer. Based on the comprehensive geochemical anomaly enrichment characteristics of the mining area, combined with the results of spectral analysis and complete rock and mineral analysis, and considering the metallogenic geological conditions of the mining area, the elements selected for geochemical analysis were determined. Sampling points were set up in the primary, secondary and tertiary water systems, and multiple sampling points were combined into one sample. A clear map of the sampling point locations was drawn. Geochemical maps were drawn based on the sampling results.

4. The method for exploring rare metal deposits in pegmatites in high-altitude and cold regions according to claim 1, characterized in that, Step S3, remote sensing geological interpretation, includes: Remote sensing data corresponding to mining areas in high-altitude and cold regions are acquired, and the remote sensing data are preprocessed. The preprocessing includes geometric correction, radiometric correction, radiometric calibration, atmospheric correction, spatial resolution unification, and background information removal. Based on the principle of selecting bands with the largest possible variance in band radiance and the smallest possible correlation between bands, we selected a combination of bands from the remote sensing data that could highlight the differences between different lithologies. Based on the spectral characteristics of pegmatite, the bands in the band combination were screened to obtain the final bands; Principal component analysis was used to analyze the data in the final band, and an alteration information extraction model was constructed based on the analyzed data. The alteration of pegmatite was then extracted based on the alteration information extraction model.

5. The method for exploring rare metal deposits in pegmatites in high-altitude and cold regions according to claim 1, characterized in that, The gravity measurement method in step S3 includes: A total gravity baseline and gravity measuring points are set up in the mining area. The gravity value of the measuring point is the relative gravity value relative to the total baseline. The gravity of the measuring point is observed using the single-pass observation method. Gravity values ​​are calculated based on gravity observation data from measuring points. The calculations include corrections for normal field, height, Bouguer, topography, and solid tides. Topography corrections are applied to near, middle, and far-field regions. Near-field corrections are calculated using a cone formula, and the topography correction values ​​are obtained using the formula... 远 Calculate, where, , , , These represent the topographic correction values, near-field topographic correction values, mid-field topographic correction values, and far-field topographic correction values, respectively. The gravity calculation results are quality checked, and the accuracy is measured by the mean square error.

6. The method for exploring rare metal deposits in pegmatites in high-altitude and cold regions according to claim 1, characterized in that, The audio magnetotelluric method in step S3 includes: Acquire magnetotelluric sounding data within the mining area and preprocess the data, including editing, smoothing, and static correction; One-dimensional continuous medium inversion was performed on the preprocessed data to obtain sounding curves, apparent resistivity profiles, and phase profiles. Based on the one-dimensional continuous medium inversion results, a two-dimensional continuous medium inversion is performed; Geoelectric models are established based on the inversion structures of one-dimensional and two-dimensional continuous media. Geological interpretation is then performed based on the geoelectric models to obtain apparent resistivity and phase.

7. The method for exploring rare metal deposits in pegmatites in high-altitude and cold regions according to claim 1, characterized in that: In step S4, a mineral exploration model is established based on the DSI spatial interpolation algorithm.

8. The method for exploring rare metal deposits in pegmatites in high-altitude and cold regions according to claim 7, characterized in that: The prospecting model includes a three-dimensional surface and borehole model, a three-dimensional stratigraphic model, a three-dimensional geological body model, and a three-dimensional physical model. The three-dimensional physical model includes a gravity model and an AMT model.

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