Method for delineating prospective mineralization areas of three rare metals using aerial radiography and geochemical data

Abstract

The method of delineating the prospective mineralization areas of three rare metals by using aerial radiography and geochemical data belongs to the technical field of research on mining area determination methods. The present invention mainly uses two types of data, 1:50,000 aerial radiography and 1:200,000 geochemical measurement, to delineate the prospective mineralization areas. The above two types of data have the characteristics of not requiring a lot of money and time to complete. Among them, the 1:200,000 geochemical measurement covers almost all land areas and analyzes a wide variety of elements, almost covering most of the main types of three rare elements; the 1:50,000 aerial radiography data uses aircraft for aerial measurement, which has the characteristics of low cost and high speed, and many provinces have completed the work of full coverage of 1:50,000 aerial radiography.

Description

Technical Field

[0001] The present invention belongs to the technical field of research on mining area determination methods, and in particular relates to a method for delineating three rare metal mineralization prospective areas by using aerial radiography and geochemical data. Background Art

[0002] The European Union's 2018 report, "Critical Raw Materials and the Circular Economy," lists 27 types of critical metals, while the United States' 2017 report, "Critical Mineral Resources of the United States: Economic and Environmental Geology and Future Supply Outlook," lists 43. While the types and quantities of critical metals listed by different countries vary, the vast majority of these elements fall into the categories of rare metals (such as Li, Be, Rb, Cs, Nb, Ta, Zr, Hf, and W), rare earth metals (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Y), and dispersed metals (Ga, Ge, Se, Cd, In, Te, Re, and Tl), collectively referred to as the "three rare" elements. In the national mineral resources planning for 2016-2020, my country plans to designate oil, natural gas, shale, coal, coalbed methane, uranium, iron, chromium, copper, aluminum, gold, nickel, tungsten, tin, molybdenum, antimony, cobalt, lithium, rare earths, zirconium, phosphorus, potassium salt, crystalline graphite, fluorite, etc. as strategic minerals.

[0003] Rare earth elements (REEs) have irreplaceable and significant applications in emerging industries such as new materials, new energy, and information technology. In comparison, my country's exploration and research on rare earth elements (REEs) is low. Traditionally, mineral exploration in my country has primarily relied on 1:50,000 geochemical survey anomalies combined with 1:50,000 geological mapping results to delineate prospective mineralization zones. Since the utilization of these REEs has only rapidly increased in recent years with technological advancements, many provinces' 1:50,000 geochemical surveys have not included REE analysis, resulting in the failure to delineate prospective mineralization zones corresponding to these REE minerals. Re-conducting 1:50,000 geochemical surveys, sampling, and analysis would waste significant time and money. Traditional methods for delineating prospective mineralization zones primarily rely on 1:50,000 geochemical survey data. Due to a lack of prior attention and understanding of REEs in my country, most completed 1:50,000 geochemical surveys have omitted REE analysis. According to data released by the China Geological Survey in 2017, nearly all of the 1:50,000 geochemical survey work covering 3.33 million square kilometers has been completed nationwide. If 1:50,000 geochemical surveys were to be conducted over the entire 3.33 million square kilometers, the cost of such a survey, according to the 2020 China Geological Survey budget, would be approximately 2,000 yuan per square kilometer. This would require at least ten years of work and nearly 10 billion yuan from geological survey agencies nationwide to complete. Acquiring such data is both costly and time-consuming. In summary, rare earth elements such as niobium, tantalum, rubidium, and yttrium are the foundation of various emerging high-tech materials, and demand is high. Rapid and economical exploration of these rare earth minerals is imperative. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem that traditional methods require high capital costs and a long time to delineate prospective mineralization areas of three rare elements. A method for delineating prospective mineralization areas of three rare metals using aerial radioactivity and geochemical data is provided. The method uses 1:50,000 aerial radioactivity measurement with low capital cost and short time and 1:200,000 geochemical measurement data that has almost completed nationwide coverage as important basis to delineate prospective mineralization areas of three rare elements such as niobium, tantalum, rubidium and yttrium.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A method for delineating prospective mineralization areas of three rare metals using aerial radiography and geochemical data, the method steps are as follows:

[0007] Step 1: Collect 1:250,000 geological maps, 1:200,000 geochemical maps, and 1:50,000 airborne gamma ray spectrometry data of the study area, and analyze the three rare elements with high background in the study area; high background refers to high concentrations of elements;

[0008] Step 2: Vectorize the collected 1:250,000 geological maps and the selected 1:200,000 geochemical maps of the three rare elements with high background using MapGIS software, assign them spatial positions, and convert them into the same area and scale, using a 1:50,000 scale map;

[0009] Step 3: Create new line files on the vectorized geochemical maps of each element, circle the high background area, use the converted 1:50,000 scale geological map as the base map, and add the 1:200,000 geochemical high background area to the geological map;

[0010] Step 4: Convert the U and Th contour maps collected from the airborne geophysical survey of the study area to a scale of 1:50,000 and cut them into maps with the same area and location as the geological map; based on the mineralization characteristics of the three rare earth elements, use the U and Th contour maps to delineate the high U and Th value ranges that may be related to mineralization;

[0011] Step 5: The high-value ranges of geochemical elements and the high-value ranges of U and Th are all included in the geological map. Based on the geological characteristics, the overlapping areas of the high-value ranges of geochemical elements and the high-value ranges of U and Th from the aerial radiography are delineated as prospective mineralization areas. As the ore body may be affected by strata and shallow cover, the prospective area may be slightly larger than the anomaly area.

[0012] Step 6: Statistical analysis will be conducted on the aerial survey data within the prospective mineralization area. The U and Th values ​​at each point will be counted and the arithmetic average will be calculated to obtain the average U and Th values ​​within the prospective area. If the U average value / Th average value is less than 0.3, it is a Th anomaly. If the U average value / Th average value is 0.3-0.7, it is a mixed anomaly of U and Th. If the U average value / Th average value is greater than 0.7, it is a U anomaly. If it is a uranium-thorium mixed anomaly or a thorium anomaly, it preliminarily indicates the presence of a large-scale isomorphous phenomenon in the area.

[0013] Step 7: Select the area with the maximum U and Th values ​​in the 1:50,000 aerial survey within the area, and arrange the 1:10,000 area or profile ground gamma spectrum work. First, paste the measured U and Th data values ​​into the EXCLE table, and then import the table into the Jinwei software to obtain the mean value X and standard deviation S d ;Finally, follow "X+S d ”, “X+2S d ”, “X+3S d "The U and Th values ​​in the area were divided into high-field, high-field and abnormal values; the abnormal maps were circled according to the values ​​greater than the abnormal values, and the U and Th abnormal maps were circled;

[0014] Step 8: Conduct engineering exposure on U and Th anomalies. If industrial ore bodies or mineralization phenomena are found within the anomalies, the prospective area defined in step 5 can be determined as the xx mineralization prospective area.

[0015] Furthermore, in step 4, when delineating the scope of the high-value area, attention should be paid to delineating small areas of high background in large areas of medium and low background, linear high-value anomalies, areal high-value anomaly areas in the contact zone of geological bodies, and large areas of high-value anomaly areas corresponding to igneous rock bodies.

[0016] Furthermore, in step 4, when delineating high-value anomalies, there is no need to select a fixed high-value range, and a relatively high-value area can be selected according to the characteristics of the geological body.

[0017] The present invention offers the following advantages over existing technologies: It utilizes 1:200,000 geochemical surveys and 1:50,000 airborne radioactive data to replace 1:50,000 geochemical surveys for the delineation of prospective mineralization areas. The 1:200,000 geochemical survey data covered the entire country as early as the 1980s, analyzing a wide range of elements, including the major three rare earth elements (RASs). The 1:50,000 airborne radioactive data covers most of the country's territory, and even if some areas remain uncovered, the use of aircraft significantly reduces costs and time. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 For regional geological maps;

[0019] Figure 2 It is a regional geological and mineral map;

[0020] Figure 3 This is a 1:50,000 uranium content contour map;

[0021] Figure 4 This is a 1:50,000 thorium content contour map;

[0022] Figure 5 This is a 1:50,000 scale map of the high uranium content area;

[0023] Figure 6 This is a 1:50,000 map of the high-value thorium content area;

[0024] Figure 7 It is the superposition map of geophysical and geochemical anomalies;

[0025] Figure 8 Delineate prospective mineralization areas;

[0026] Figure 9 This is the Th anomaly map. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the spirit and scope of the technical solution of the present invention should be included in the scope of protection of the present invention.

[0028] This method primarily utilizes 1:50,000 aerial radiographic and 1:200,000 geochemical survey data to delineate prospective mineralization areas. These two types of data require little capital and time to complete. The 1:200,000 geochemical survey covers nearly the entire land area, while analyzing a wide range of elements, including most of the major three rare elements. The 1:50,000 aerial radiographic survey, conducted using aircraft, is low-cost and fast, and many provinces have already completed full coverage with 1:50,000 aerial radiographic surveys.

[0029] The key point of this invention is to apply the principle of isomorphism based on the physical and chemical properties of radioactive elements, indirectly imparting the geophysical characteristics of radioactive fields to the three rare elements, which are not radioactive. Simultaneously, by utilizing the regularity of the uranium-thorium ratio in geochemistry, the necessary parameters for thorium anomalies and uranium-thorium mixing anomalies are analyzed and determined, thereby enabling the delineation of prospective mineralization areas for the three rare elements.

[0030] The fundamental principle behind this method, which uses 1:50,000 aerial radiographic and 1:200,000 geochemical data instead of 1:50,000 soil geochemical data, is that rare earth elements (REMs) rarely form as single elements; instead, they form deposits as combinations of multiple elements. The main REM minerals include allanite, monazite, yttrium-tantalite, qubicurite, xenotime, spodumene, lepidolite, ferroleum mica, niobium-tantalite, ferroniite, ferroniite, ferroniite, ferroniite, ferroniite, ferroniite, pyrochlore, zircon, and hafnium-zircon. The occurrence states of REMs primarily include isomorphous, isolated minerals, organically bound, and adsorbed. Uranium, with its large ionic radius, readily undergoes isomorphic reactions with elements of similar ionic radius, such as Th, Ce, Zr, Ti, Nb, Ta, Mo, W, Ca, and REEs, forming uranium-rich pyrochlores, including thorium-thorium monazite, allanite, niobium-tantalite, and uranium-rich pyrochlore. This isomorphic interaction is widespread in rare earth (REE) deposits. Consequently, rare earth (REE) deposits often contain radioactive elements (such as U and Th). The presence of these elements can generate radioactive field lines, making the use of airborne radiometric measurements to identify prospective rare earth (REE) mineralization areas theoretically feasible. The fundamental cause of high radioactive fields is high concentrations of radionuclides such as U, Th, and K. These high concentrations can be caused by isolated U, Th, and K deposits, or by the formation of U- and Th-bearing minerals through isomorphic interactions. Therefore, the 1:200,000 geochemical survey data is used to determine whether the region has the geochemical background for the formation of three rare element minerals. The prospective mineralization areas for three rare element metal deposits can be delineated by combining the 1:50,000 aerial radiography and 1:200,000 geochemical survey data.

[0031] Example 1:

[0032] In Yichun, Heilongjiang Province, the method of the present invention was used to delineate a prospective niobium and rubidium mineralization area (niobium and rubidium are three rare elements), and through engineering verification, a niobium industrial ore body was discovered in the prospective area, proving the effectiveness of the method. The specific implementation is as follows:

[0033] ①Collect the 1:250,000 geological map, 1:200,000 geochemical map and 1:50,000 airborne gamma spectroscopy data of the study area; analyze and select the types of three rare elements with high background areas in the 1:200,000 geochemical map (high background areas can be directly observed in the collected data). After observation and screening, it was found that Nb and Rb elements have high background in this area.

[0034] ② First, use the MAPGIS software to vectorize the collected 1:250,000 geological map and 1:200,000 geochemical map of NbRb elements and assign them spatial positions; then, convert the selected maps into the same area and scale. It is recommended to use a 1:50,000 scale map;

[0035] ③ Create new NbRb line files on the 1:200,000 geochemical map of the vectorized elements and delineate the high background area. Use the converted 1:50,000 scale geological map as the base map ( Figure 1 ), add the 1:200,000 geochemical high background range to the geological map ( Figure 2 ).

[0036] ④ Collect the Yichun area aerial release contour map, convert its scale into 1:50,000 and cut it into Figure 1 Maps of the same area and location ( Figure 3 、 4 ). According to the mineralization characteristics of the three rare earth minerals, Figure 1 and Figure 3 By comparison and combining the physical characteristics of geological bodies, the high value range of U and Th that may be related to mineralization was preliminarily identified (such as Figure 5 、 6 When delineating the high-value area, attention should be paid to delineating small areas of high background in a large area of ​​medium-low background, linear high-value anomalies, areal high-value anomaly areas in the contact zone of geological bodies, and large areas of high-value anomaly areas corresponding to igneous rock bodies. When delineating high-value anomalies, there is no need to select a fixed high-value range, and relatively high-value areas can be selected according to the characteristics of the geological body.

[0037] ⑤ The high value ranges of Nb and Rb elements and the high value ranges of U and Th are all included in the geological map to form Figure 7 Combined with geological characteristics, the overlapping areas of geochemical high value range and aerial radiometric U and Th high value range are delineated as mineralization prospective areas ( Figure 8 Since the ore body may be affected by strata, shallow cover, etc., the prospective area may be slightly larger than the anomaly area.

[0038] ⑥ Statistical analysis of aerial radiometric data from survey points within the prospective mineralization area revealed that the U and Th values ​​at each point were calculated and averaged. The average U value for prospective area I was 1.8, the average Th value was 7.6, and the U / Th ratio was 0.23, indicating a thorium anomaly. The average U value for prospective area II was 2.7, the average Th value was 8.4, and the U / Th ratio was 0.32, indicating a uranium-thorium anomaly. High U / Th values ​​within the high-value range of aerial radiometric data within the prospective area, indicating the presence of a large-scale isomorphic phenomenon within the area.

[0039] ⑦ Select the U and Th maximum value area in the 1:50,000 aerial radiography within the initially delineated prospect area, and arrange the 1:10,000 area ground gamma spectrum work. First, paste the measured U and Th data values ​​into the EXCLE table, and then import the table into the Jinwei software to obtain X and S d ;Finally, follow "X+S d ”, “X+2S d ”, “X+3S d The U and Th in the area were divided into high field, high field and abnormal field. The division results are shown in Table 1. The abnormal map is circled according to the value greater than the abnormal value, and the U and Th abnormal maps are circled (as shown in the figure). Figure 9 ).

[0040] Table 1 Energy spectrum abnormality level

[0041]

[0042] ⑧ Comparative observations show that the delineated Th anomaly map is larger and more coherent than the U anomaly map, and the measured Th anomaly maximum is larger. Engineering excavation of the ThCO5 anomaly revealed chemical analysis of Nb and Rb industrial ore bodies (diagram xx). The discovery of these industrial ore bodies demonstrates the potential for NbRb mineralization in this area, arguing that it can be designated as a prospective mineralization zone.

Claims

1. A method for delineating prospective mineralization areas of three rare metals using aerial radiography and geochemical data, characterized by: The method steps are: Step 1: Collect 1:250,000 geological maps, 1:200,000 geochemical maps, and 1:50,000 airborne gamma ray spectrometry data of the study area, and analyze the three rare elements with high background in the study area; Step 2: Vectorize the collected 1:250,000 geological maps and the selected 1:200,000 geochemical maps of the three rare elements with high background using MapGIS software, assign them spatial positions, and convert them into the same area and scale, using a 1:50,000 scale map; Step 3: Create new line files on the vectorized geochemical maps of each element, circle the high background area, use the converted 1:50,000 scale geological map as the base map, and add the 1:200,000 geochemical high background area to the geological map; Step 4: Convert the U and Th contour maps collected from the airborne geophysical survey of the study area to a scale of 1:50,000 and cut them into maps with the same area and location as the geological map; based on the mineralization characteristics of the three rare earth elements, use the U and Th contour maps to delineate the high U and Th value ranges that may be related to mineralization; Step 5: The high-value ranges of geochemical elements and the high-value ranges of U and Th are all included in the geological map; based on the geological characteristics, the overlapping areas of the high-value ranges of geochemical elements and the high-value ranges of U and Th from the aerial radiography are delineated as prospective mineralization areas; Step 6: Statistical analysis will be conducted on the aerial survey data within the prospective mineralization area. The U and Th values ​​at each point will be counted and the arithmetic average will be calculated to obtain the average U and Th values ​​within the prospective area. If the U average value / Th average value is less than 0.3, it is a Th anomaly. If the U average value / Th average value is 0.3-0.7, it is a mixed anomaly of U and Th. If the U average value / Th average value is greater than 0.7, it is a U anomaly. If it is a uranium-thorium mixed anomaly or a thorium anomaly, it preliminarily indicates the presence of a large-scale isomorphous phenomenon in the area. Step 7: Select the area with the maximum U and Th values ​​in the 1:50,000 aerial survey within the area, and arrange the 1:10,000 area or profile ground gamma spectrum work. First, paste the measured U and Th data values ​​into the EXCLE table, and then import the table into the Jinwei software to obtain the mean value X and standard deviation S d ;Finally, follow "X+S d ”、"X+2S d ”、"X+3S d "The U and Th values ​​in the area were divided into high-field, high-field and abnormal values; the abnormal maps were circled according to the values ​​greater than the abnormal values, and the U and Th abnormal maps were circled; Step 8: Conduct engineering exposure on U and Th anomalies. If industrial ore bodies or mineralization phenomena are found within the anomalies, the prospective area defined in step 5 can be determined as the xx mineralization prospective area.

2. The method for delineating prospective mineralization areas of three rare metals using aerial radiography and geochemical data according to claim 1, characterized in that: In step 4, when delineating the high-value area, attention should be paid to delineating small areas of high background in large areas of medium and low background, linear high-value anomalies, areal high-value anomaly areas in the contact zone of geological bodies, and large areas of high-value anomaly areas corresponding to igneous bodies.

3. The method for delineating prospective mineralization areas of three rare metals using aerial radiography and geochemical data according to claim 2, characterized in that: In step 4, when delineating high-value anomalies, there is no need to select a fixed high-value range. Instead, a relatively high-value area can be selected based on the characteristics of the geological body.

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