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Article

Sustainable Exploration, Mining, and Utilization of a Rare Earth Deposit in Southeastern Guangxi: Insights into Metallogenic Regularity

1
School of Earth Sciences, Yangtze University, Wuhan 430100, China
2
School of Civil Engineering and Surveying Engineering, Guilin University of Technology Nanning Branch, Nanning 530001, China
3
Remote Sensing Center of Guangxi, Nanning 530000, China
4
Guangxi Geological and Mineral Exploration and Development Bureau, Nanning 530000, China
5
Guangxi Zhuang Autonomous Region 274 Geological Team, Beihai 536000, China
*
Authors to whom correspondence should be addressed.
Sustainability 2025, 17(6), 2552; https://doi.org/10.3390/su17062552
Submission received: 17 February 2025 / Revised: 10 March 2025 / Accepted: 12 March 2025 / Published: 14 March 2025

Abstract

:
In this study, we investigated and evaluated the mineralization pattern of ion-adsorption rare earth deposits in granite weathering crusts using remote sensing technology for the southeastern region of Guangxi, and we proposed a strategy for sustainable mining and utilization. Through detailed analysis of the stratification characteristics, mineralogical features, and rare earth element (REE) distribution patterns of the weathering crust, it is found that the rare earth minerals are mainly enriched in the completely weathered layers, with light rare earth elements (La, Ce, Pr, Nd) dominating. This study reveals the transformation mechanism of rocks and minerals during the weathering process, especially the important role of kaolinite, feldspar, and smectite in the enrichment of rare earth elements. Combined with remote sensing image analysis, the intrinsic connection between linear tectonics and mineralization is explored, and potential directions for sustainable exploration are proposed. This study deepens the understanding of the mineralization mechanism of rare earth deposits in the region and provides scientific basis and technical support for the sustainable exploration and development of rare earth resources, and it has important economic and environmental significance.

1. Introduction

Rare earth elements (REEs) are critical components in modern technology, playing a pivotal role in various industries such as electronics, renewable energy, and advanced materials. The sustainable extraction and utilization of rare earth mineral resources are thus of utmost importance. This study aims to further elucidate the metallogenic regularities of rare earth deposits in southeastern Guangxi and propose strategies for sustainable extraction and utilization, thereby promoting the sustainable development of rare earth resources. In recent years, significant progress has been made in the study of rare earth minerals in Guangxi. This progress is mainly evident in the enhanced optimization of mineral processing techniques, mineral exploration, environmental governance, and resource recovery. These developments cover the extraction [1], recovery [2], leaching [3], adsorption [4], mineral processing [5], kinetics [6], distribution [7], and mineralization mechanism [8,9], as well as multiple aspects of the heap leaching process [10,11]. By optimizing the beneficiation process, for example, using ammonium sulfate as a leaching agent, REE leaching and recovery rates have been significantly improved. Additionally, by adding surfactants such as hexadecyltrimethylammonium chloride and polyethyleneimine, the leaching efficiency and permeability of REEs have been further improved. During mineral exploration, a new target of light and heavy REE superimposed deposits in the weathering crust has been proposed. Good results have been achieved in actual explorations, revealing the indicative role of the geochemical characteristics of Yanshanian granite in southeastern Guangxi for rare earth mineralization [12,13]. Additionally, advances have been made in environmental protection treatment and resource recovery, with new methods proposed for recovering residual ammonium from tailings and suppressing swelling during leaching processes [14,15].
A systematic evaluation of the distribution of mineral resources and the potential mineralization zones in Guangxi was conducted, providing a scientific basis for future exploration. By optimizing a quantitative remote sensing prediction model, the prediction accuracy of ion-adsorption rare earth deposits has been improved, providing a new means for the rapid and effective development of mineral resources [16,17]. Previous studies have considered the occurrence of REEs [18], their mineralization characteristics [19], leaching technology and the development of leaching agents [20,21], as well as the dynamic characteristics of the leaching process for leaching-type rare earth ores in the weathering crust [22]. These studies have established a scientific basis and provide technical support for the rational development and utilization of REE resources.
In recent years, 33 institutions, including the China Institute of Geology, have conducted in-depth investigations on these resources [23]. Important results have been obtained regarding the metallogenic regularity of REE deposits and innovative exploration techniques have been developed [24,25]. In-depth research has also been conducted on the characteristics and ore-forming mechanisms of hydrothermal deposits related to granite [26,27]. The rational development and utilization of these REE resources, the strengthening of exploration and ecological protection, the expansion of applications, and the transformation of resource advantages into economic advantages are urgently needed for economic development and to ensure the sustainable development of REE resources.

2. Geological Background

In terms of geological and geodynamic background, the mine area is located in the north side of the Dayaoshan uplift of the Guizhong-Northeastern Guizhong fold system in the South China activity belt and has gone through multiple phases of crustal movements such as the Caledonian, the Hercynian, the Yanshan, and the Himalayan. The stratigraphy of the area is complex and diversified, covering several stratigraphic units from the Aurignacian System to the Quaternary System. Cambrian, Devonian, and Carboniferous strata are mainly exposed in the mine, and the characteristic strata include grayish-black shale and sandstone of the Cambrian Upper Bianxi Formation, purple-red conglomerate and sandstone of the Devonian Lianhuashan Formation, and yellowish-gray mudstone and sandstone of the Carboniferous Yingtang Formation.
The rock beds are of excellent quality. The mine is located in the southeast of the Huashan granite body intruded in the early Yanshan period, and the lithology is dominated by fine-to-medium coarse-grained mottled black mica granite and rich in feldspars, quartz, and a small amount of mica, amphibole, and other minerals, with a high content of rare earth, tungsten, lead, and other beneficial elements, which is extremely favorable for rare earth mineralization. Trace element analysis shows that W, Pb, As, and other elements are enriched, indicating that the rock body has good potential for the formation of tungsten ore, lead–zinc ore and rare earth deposits.
The ore mineral composition is rich, mainly including clay minerals (e.g., kaolinite, illite) and weathering residual granite minerals (e.g., feldspar, quartz), and contains zircon, monazite, yttrium phosphorite, and other secondary minerals. The surrounding rock types are mainly the top plate (clayed slope accumulation layer or fully weathered layer) and the bottom plate (semi-weathered layer or original rock) of the ore body, with the top plate mostly clayed more thoroughly and the bottom plate dominated by the semi-weathered layer.
The type of the deposit is clear; it is a granite weathering crust ion-adsorption rare earth deposit, or, in other words, rare earth elements in the ion-adsorption state in the granite weathering crust. The formation of the deposit went through two stages of endogenous magmatism and epigenetic weathering, resulting in the formation of the present rare earth ore body.
The study area was located in the southeast of the Huashan rock mass in Hezhou City, covering an area of approximately 1200 km2. It can be divided into two mining areas, i.e., the northern and southern sections, at the intersection of the Dayao Mountain uplift and the Nanling Mountain granite tectonic belt. In terms of tectonic location, the Huashan–Guposhan rock mass is distributed in a dumbbell-shaped east–west orientation (Figure 1).
This area is part of the Huashan granite intrusion that originated during the early Yanshan period (Late Jurassic). It is mainly located within the transitional facies zone, with the western edge extending to the internal facies zone. The edge facies have developed in some local areas, especially in the high-slope areas in the northeast and east of Beicao Village [28,29]. There are also silicified fault zones distributed in the mining area, which are often covered by weathered layers but can be identified through manual exposure, water erosion exposure, and silicification markers. The fault structure is mainly oriented in the northeast and northwest directions, with a relatively small scale. The fault features weathering phenomena such as chloritization and sericitization.
From the perspective of magmatic activity, the mining area is located in the southeastern region of the Huashan granite body. It is mainly positioned within the transitional phase zone, with the western edge located in the internal phase zone. The marginal facies are poorly developed and can only be seen locally. Furthermore, the transition between lithofacies is unclear, displaying a gradual and indistinct characteristic (Figure 2).

3. Materials and Methods

A total of 11,352 basic analysis samples, 1556 leaching samples, 68 volumetric mass samples, and 26 REE dispensing samples were collected, which ensured the representativeness and adequacy of the sampled data (Table 1). In terms of methodology, we fully utilized GPS for terrain measurement and geological engineering survey. We constructed a high-precision E-class GPS control network and adopted GPS real-time kinematic (RTK) technology for engineering point layout, data collection, and further measurement. Specifically, the positioning accuracy of the GPS system reached centimeter level, and even millimeter level under certain conditions, ensuring the accuracy of measurement data. Geological mapping was conducted to delineate the geological structure and geomorphological characteristics of the mining area in detail, accurately identifying the boundary of the weathered crust. The prospecting project was mainly based on drilling for samples, supplemented by shallow well engineering, which ensured effective control of the ore body. Sample testing was undertaken by the Guilin Mineral Geological Testing Center with a Grade A qualification, utilizing an advanced inductively coupled plasma mass spectrometry method for sample analysis. Strict internal and external quality inspections were conducted to ensure the accuracy and reliability of the analysis data. Additionally, comprehensive hydrogeological work was conducted, including a 1:50,000 regional hydrogeological survey and a 1:5000 mining area hydraulic ring geological survey. These methods collectively supported the core goals of our research, which were to elucidate the metallogenic regularities and propose sustainable mining and utilization strategies for rare earth deposits in southeastern Guangxi.
Table 1 presents the detailed analytical results of rare earth oxide compositions from the main drilling holes in the study area. The data reveal that rare earth elements are primarily enriched in the fully weathered layer of the granite, with light REEs (La, Ce, Pr, and Nd) dominant. This is consistent with our observations of the weathering crust and the enrichment characteristics of REEs. The variability in REE contents among samples can be attributed to differences in the degree of weathering, mineralogical changes, and the initial abundance of REEs in the original rock. The high REE contents in some samples indicate the potential for high-quality rare earth ore deposits in the study area.

4. Results

4.1. Characteristics of the Ore Body Distribution

There were six ore bodies (Nos. 7, 8, 10, 12, 13, and 14) in the study area (Figure 3). The ore bodies were located in a granite weathered crust, which was the mineralization and ore-bearing site of the REEs. Rare earth oxides were enriched in the middle and upper parts of the weathered crust, and the main ore-bearing horizon was a granite full-weathering layer. The plane distribution of the ore body was affected by the morphology of the weathered crust. While the ore body remained intact, it has been strongly denuded in elevated areas, potentially leading to exposed, thin, or skylight phenomena. The ore body in the lower terrain was divided into islands by valleys. The edges were mostly extended in the form of a harbor. In the profile, the ore body was layered, with REEs occurring in the granite full regolith layer, which undulated with the terrain. The dip angle of the floor ranged from 10° to 30°. Most of the ore bodies were exposed, and a few were covered by slope deposits or residual soil layers. The floor was predominantly a semi-weathered bedrock. The specific characteristics of the ore body in the mining area are shown in Table 2.

4.2. Planar Distribution Characteristics of the Weathered Crust

The Huashan—Guposhan rare earth deposit is a granite weathering crust ion-adsorption type deposit. Rare earth elements exist in the Earth’s crust in the form of ion adsorption. The development of the weathering crust varies due to uneven weathering and terrain changes. The edge of the study area had a high elevation, and the center had a lower elevation, while the north–south terrain was relatively flat and the surrounding terrain was higher. The study area was composed of medium-to-low mountains and hills, with a gentle terrain ranging from 220 to 800 m above sea level and well-developed gullies. The weathered crust was usually 1 to 45 m thick, with an average thickness of over 11 m, and was prominent on gently sloping areas and mountain slopes covered by vegetation. In regions with sparse vegetation, the cutting of ditches resulted in the formation of new gullies and crustal damage. Some mountaintops and slopes were eroded, revealing bedrock and rare weathered granite balls.

4.3. Vertical Variation and Mineralization Characteristics of the Weathered Crust

Due to the uneven intensity of weathering, combined with the influence of landforms and other factors, significant variations were observed in the structure and material composition of the regolith across the vertical section. Following a thorough analysis, the regolith in the study area was delineated into four distinct layers from top to bottom: the topsoil layer (which is the uppermost part of the regolith, rich in organic matter and fine-grained minerals), the fully weathered layer (where rocks have been completely broken down into smaller particles by the weathering processes), the semi-weathered layer (characterized by partially weathered rocks with a mix of fresh and altered minerals), and the bedrock (the underlying, unweathered, or minimally weathered rock layer). Idealized cross-sections of these regolith layers are illustrated in Figure 4.
In the study area, the surface layer was a weathered soil layer with a typical thickness ranging from 0.5 to 4.0 m, with a thin or missing humus layer (0.1–0.3 m). It had a gray-black to green color and was composed of loam, sand, and plant roots. The lower layer was a red clay layer (0.2–0.3 m thick) with a clay content of 40–60% and occasional bedrock gravel. The thickness of topsoil varied, with the mountaintop thinner (0.3–1.5 m) and the ridges and foothills thicker (averaging 2 m). Below the topsoil was a completely weathered layer (with a thickness ranging from 1 to 40 m). It had a yellow-brown color with gray-white patches and uniform texture, and it contained kaolin feldspar. Above it was a semi-weathered layer (several to tens of meters thick) with reduced clay content (15–20%), which was similar to primitive rocks and was possibly rich in REEs. The weathering process and mineralogical changes affected the enrichment of REEs, among which the presence of kaolinite, mineral alterations, layer thickness, and clay content played a key role.

4.4. Characteristics of the Rock Structure and Texture

The rocks in the research area were porphyritic biotite granite, with varying characteristics from the edge to the transition phases. The color sequence shifted from light red to gray-white and back to light red to gray-white. Additionally, the mineral structure evolved from fine to medium grain, eventually culminating in a medium coarse-grained porphyritic granite structure dominated by a medium grain. The rocks were mainly composed of minerals such as quartz (Figure 5A), plagioclase, biotite, and amphibole (Figure 5B). The phenocryst content was 15–20%. They were mainly composed of potassium feldspar phenocrysts, some of which were quartz and plagioclase phenocrysts. Potassium feldspar occurred mostly in the form of subhedral columns and plates, while plagioclase occurred mostly in the form of subhedral columns and plates, often with clustered twin crystals. Within the feldspar, some particles developed cracks, which had locally eroded into sericite, and some particles had ring structures. The matrix was mainly composed of plagioclase, quartz, and a small amount of microcline feldspar and biotite (Figure 5C). Quartz was mostly in the form of xenomorphic granules, while biotite was distributed unevenly in the form of flakes or subhedral flakes among the felsic minerals. Some particles contained apatite inclusions, and some biotite crystals were eroded into chlorite, retaining only their appearance (Figure 5D). Occasionally, scaly muscovite was observed. Individual particles exhibited Karnofsky twinning, while sporadic occurrences of subhedral to xenomorphic granular pyrite were observed. The rock was described as having a gray-white light-red flesh. It was further classified as porphyritic fine-grained biotite granite, with a medium-grained porphyritic granite structure, medium fine-grained granite structure, or massive structure, mainly consisting of quartz and feldspar with a small amount of biotite.
The mining area was characterized by a limited number of late intrusive fine-grained granite bodies, which were usually manifested as veins and small rock masses, with clear boundaries with the main rock mass. These granites were light red to gray-white in color, with a fine-grained structure. They were mainly composed of orthoclase, plagioclase, quartz, and a small amount of biotite and muscovite. Additionally, rock veins with unknown ages mainly faced northwest. The granite near the mining area was mainly composed of feldspar and quartz, and the mineral composition of different rock types and phases varied (Table 3). From a chemical perspective, Huashan granite was rich in silicon and alkali but lacked iron, magnesium, and calcium. It was characterized by aluminum supersaturation.

4.5. The REE Enrichment Characteristics of the Granite Weathering Crust

Based on the data presented in Table 4, we were able to determine the total (TR2O3) and leachable (SR2O3) contents of rare earth oxides in the studied granite weathering crust. The results revealed that the REE content of the original ore-forming rock was notably high, nearing or even sometimes exceeding the global average for acid granite, which is 0.0292% as reported by Vinogradov. This finding is particularly significant as it suggests that the study area is situated within a transition zone characterized by high REE content, which is highly conducive to mineralization processes.
To further elaborate on the REE enrichment characteristics, Table 5 provides a comprehensive and detailed breakdown of the composition of ore materials and the distribution of REE content within them. This table is invaluable for gaining a deeper understanding of the occurrence and distribution patterns of REEs in ores. It not only presents the proportions of different material components, such as detrital and clayey fractions, but also outlines the REO contents and their respective contributions to the overall REE content of the samples.
By analyzing the data in Table 5, we can gain insights into how REEs are distributed within the various components of the ore materials. This information is crucial for understanding the geological processes that led to the enrichment of REEs in the study area and for predicting the potential for further mineralization.
Moreover, the detailed information on ore material composition and REE content distribution provided by Table 5 is of great significance for the subsequent beneficiation and smelting processes. Knowledge of the specific REE content and distribution within the ore materials can guide the selection of appropriate processing techniques to efficiently extract and refine the REEs. This, in turn, can enhance the economic viability of mining operations in the study area and contribute to the sustainable development of the rare earth industry.
Rare earth enrichment in granite was linked to several factors. The abundance of REEs in the weathered crust was correlated with pH, organic matter content, and mineral composition. A weakly acid to near-neutral environment favored REE adsorption by minerals. Organic matter was positively correlated with REE-bearing minerals and aided their formation. Kaolinite and halloysite were the primary REE-bearing minerals, with their content influencing REE enrichment in the crust.
Researchers have studied the intrusion complexes in northeastern Guangxi [30], the genesis of polymetallic sulfide tin deposits in Southern China [31], and the genesis and mineralization significance of granite in southwestern China [32]. Research has shown that the mineralogical enrichment pathways of various weathered crusts rich in REEs are different. In this study area, the evolutionary sequence of the granite weathering crust developed from microcline, biotite, and plagioclase to kaolinite and orthoclase, followed by muscovite, and finally kaolinite and salt greenstone. The main geological factors limiting the development of REE-rich weathered crusts included the parent rock conditions, climatic conditions, neotectonic conditions, and geomorphic conditions.
According to the REE composition curves in Figure 6 and Figure 7, the granite in this area displayed a right-dipping trend, indicating the enrichment of light REEs with obvious right-dipping anomalies and negative europium (Eu) anomalies. Quartz and feldspar were the main rock-forming minerals, typically making little contribution to the REE content. Rare earth elements mainly originated from accessory minerals, especially those with a low biotite content. The distribution of REEs was minimally affected by primary minerals, while a higher contribution of biotite led to a negative transformation in the Eu anomaly. Granite metamorphism and alteration were driven by self-metasomatism, hydrothermal alteration, and contact alteration, all of which affected the REE content. Processes such as muscovite and potassium feldspar enhanced the REE content, while silicification hindered the formation of ion-adsorbed rare earth ore bodies.

4.6. Distribution Characteristics of Ore Types and Grades

This deposit is classified as a granite weathering crust ion-adsorption rare earth ore. It originated from the weathering and leaching of primitive rocks rich in rare earth elements (REEs) and the presence of independent REE minerals. This process resulted in the migration and re-enrichment of REEs in the weathered crust, particularly in the completely weathered layer of the parent granite. Due to the formation of abundant REE oxides through adsorption and enrichment, the ore is considered easily exploitable. Based on its content and utilization of REEs as the primary useful component, it is further classified as a single rare earth ore. Specifically, it is an ion-adsorbed rare earth ore, as determined by the state of REE occurrence [33,34,35]. The study area primarily consists of this ore type.
The grade distribution of the ore in the study area mainly ranged from 0.05% to 0.13% (average, 0.080%), accounting for 93.11% of the total ore. The thickness of the ore-bearing weathering layer was positively correlated with the ore grade and leaching rate, indicating that strong and well-preserved weathering was conducive to the enrichment of REEs (Figure 8). The figure shows the influence of ore layer thickness on the leaching rate and ore grade, where the overall phase leaching rate, ion phase leaching rate, and ore grade all exhibit different trends with increasing ore layer thickness (Figure 9). This may be due to the steep terrain slope and strong erosion in the study area, which hindered the effective accumulation of REEs. These findings emphasized the importance of geological and environmental factors in controlling the distribution and enrichment of REEs.

5. Discussion

5.1. The Relationship Between Linear Features and Mineralization

The Huashan pluton is strongly associated with the mineralization of REE, tungsten tin, niobium, tantalum, and uranium polymetallic deposits. This study utilized ETM+3, 4, and 7 band data from the Landsat 7 satellite in August 2009 (Figure 10) to perform a linear structural interpretation of the Huashan rock mass (Figure 11).
The interpretation results showed that the linear structure of the Huashan rock mass was mainly in the NW and NE/NNE directions, followed by the EW direction, with a total length of nearly 849 km. The NE direction structure accounted for 56% of the total, the NW direction accounted for 40%, and the EW direction accounted for 3.94%. Previous research results (Figure 12) are consistent with this interpretation. The linear bodies were largely interpreted as fault structures, followed by joints and veins, indicating a successful interpretation.
Therefore, the Huashan–Guposhan granite body was closely related to REEs and tungsten–tin polymetallic mineralization processes. The results revealed that the linear structure of the rock mass was mainly in the NW and NE directions, which provided channels and space for mineralization. However, their occurrence was not located in the most tectonically developed area, but in the moderately developed area, indicating that moderate tectonic development was the most conducive to mineralization. In addition, the weathering process of granite was crucial for the formation of REE deposits, which existed in crystal-bound and free adsorption states, and clay minerals were the main adsorbents of rare earth oxides. The degree of weathering intensified, and the grade of REEs initially increased but then decreased, with the highest concentration typically found in the middle section of the weathered crust. This confirmed the close connection between the granite mass and mineralization processes, and it was necessary to comprehensively consider the structural characteristics, weathering process, and state of REE occurrence. Moreover, it was crucial to differentiate and account for variations in metallogenic conditions in different regions to fully understand the mineralization processes associated with the granite mass.

5.2. Analysis of Metallogenic Regularity and Prospecting Direction

Rare earth deposits adsorbed by weathering crust ions mainly occur in the weathering crust of magmatic rocks. Terrain has a significant impact on the mineralization process, with gentle slopes, wide hills, and mountaintops more favorable for mineralization, while steep slopes, narrow hills, and other areas are less favorable. The ion adsorption process in weathered crust is influenced by various factors such as groundwater flow, surface water erosion, thickness and degree of weathering of the weathered crust.
The distribution of rare earth element grades is closely related to the initial abundance of rare earth elements in the original rock. The higher the degree of weathering, the better the quality and thickness of the ore layer. In the vertical direction, the middle weathering crust has the richest content of rare earth elements and is a high-quality ore bearing layer.
The weathering crust of Huashan rock mass in the research area is widely developed and rich in rare earth oxide resources. The southern, western, and northern parts of the Huashan pluton have superior mineralization conditions, and there is a broad prospect for mineral exploration in Huangbao, Damugen, and other areas. The Guboshan rock mass also has good mineralization conditions, and multiple mineral deposits have been discovered.
Based on the evolution history of rock structures, we have inferred the direction and scale of rare earth mineral exploration. The mineralization of rare earth deposits in southeastern Guangxi is closely related to the weathering process of granite and the distribution of linear structures. Future research should focus on clarifying the weathering and mineralization mechanism, exploring the rare earth mineralization potential in other rocks and metamorphic rocks in the Nanling Mountain metallogenic belt, and developing more efficient and sustainable mining and utilization technologies.

6. Conclusions

In conclusion, this study has elucidated the metallogenic regularities of rare earth deposits in southern Guangxi and proposed strategies for sustainable mining and utilization. Our findings reveal that rare earth elements are primarily enriched in the fully weathered layer of granite, with light REEs dominant. The mineralization process is closely related to the weathering of granite and the presence of favorable geological structures. These findings provide a scientific basis and technical support for the sustainable exploration and development of rare earth resources in the region.

Author Contributions

Methodology, S.L.; data curation, Z.T.; writing the original draft—preparation, Z.Z. writing—review and editing, J.Y. and X.Y.; visualization, S.Z. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the National Deep Exploration Program Project “Mineralization Law, Deep Exploration Technology and Experiment of Dachang Ore Field” (SinoProbe-03-01-03A).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Acknowledgments

We would like to thank Lin Jinfu from the Guilin University of Technology and Gao Lele from the School of Business at Guilin University of Technology for their guidance. We also want to thank the editorial team for their careful guidance.

Conflicts of Interest

The authors declare no conflicts of interest.

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Figure 1. Overview of an REE mining right in southeastern Guangxi and a Yanshanian granite distribution map: (A) Map showing the distribution of Yanshanian granite in the research area: 1. Early Yanshanian granite rocks. 2. Late Yanshanian granite rocks. 3. Plate boundary lines. 4. Provincial boundaries. 5. Yishan Quannan Deep Fault. 6. Hezhou Chenzhou Chaling deep fault. (B) Overview of REE mining rights: 1. RRE mine working area in southeastern Guangxi. 2. North ore block. 3. South ore block research area. 4. The turning point and their numbering system in the southern mining section.
Figure 1. Overview of an REE mining right in southeastern Guangxi and a Yanshanian granite distribution map: (A) Map showing the distribution of Yanshanian granite in the research area: 1. Early Yanshanian granite rocks. 2. Late Yanshanian granite rocks. 3. Plate boundary lines. 4. Provincial boundaries. 5. Yishan Quannan Deep Fault. 6. Hezhou Chenzhou Chaling deep fault. (B) Overview of REE mining rights: 1. RRE mine working area in southeastern Guangxi. 2. North ore block. 3. South ore block research area. 4. The turning point and their numbering system in the southern mining section.
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Figure 2. Distribution of magmatic lithofacies near the south ore block: 1. Quaternary impact layer. 2. Upper Devonian System. 3. Devonian Middle Series. 4. Black mica granite. 5. Fine-grained quartz diorite. 6. Granite. 7. Fine-grained rock veins. 8. Granite fine-grained vein. 9. Pegmatite vein. 10. Real and inferred geological boundaries. 11. Lithofacies boundary. 12. Non-integrated contact boundary. 13. Fault fragmentation. 14. Appearance of the contact surface of the invading body. 15. Rock occurrence. 16. Granite vein. 17. Granite-porphyry dyke. 18. The study area.
Figure 2. Distribution of magmatic lithofacies near the south ore block: 1. Quaternary impact layer. 2. Upper Devonian System. 3. Devonian Middle Series. 4. Black mica granite. 5. Fine-grained quartz diorite. 6. Granite. 7. Fine-grained rock veins. 8. Granite fine-grained vein. 9. Pegmatite vein. 10. Real and inferred geological boundaries. 11. Lithofacies boundary. 12. Non-integrated contact boundary. 13. Fault fragmentation. 14. Appearance of the contact surface of the invading body. 15. Rock occurrence. 16. Granite vein. 17. Granite-porphyry dyke. 18. The study area.
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Figure 3. Distribution of the ore bodies in the study area.
Figure 3. Distribution of the ore bodies in the study area.
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Figure 4. Schematic diagram of the weathering crust.
Figure 4. Schematic diagram of the weathering crust.
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Figure 5. Characteristics of the rocks and minerals under the microscope. (A) Display areas of mica, quartz, and localized alteration to sericite. (B) Display the distribution of mica, plagioclase, and locally altered sericite. (C) Display areas of potassium feldspar and local alteration. (D) Display mica, chlorite, local alteration, and inclusions in mica.
Figure 5. Characteristics of the rocks and minerals under the microscope. (A) Display areas of mica, quartz, and localized alteration to sericite. (B) Display the distribution of mica, plagioclase, and locally altered sericite. (C) Display areas of potassium feldspar and local alteration. (D) Display mica, chlorite, local alteration, and inclusions in mica.
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Figure 6. Normalization plot of REE composition for Huashan granite.
Figure 6. Normalization plot of REE composition for Huashan granite.
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Figure 7. The REE composition model curve of rock-forming minerals in Huashan granite.
Figure 7. The REE composition model curve of rock-forming minerals in Huashan granite.
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Figure 8. The distribution of ore grade proportions.
Figure 8. The distribution of ore grade proportions.
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Figure 9. The relationship between ore thickness and ore grade.
Figure 9. The relationship between ore thickness and ore grade.
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Figure 10. A remote sensing image of Huashan granite after geometric correction.
Figure 10. A remote sensing image of Huashan granite after geometric correction.
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Figure 11. A remote sensing linear structure interpretation of the Huashan rock mass: a, The three groups of tectonic altered granite vein zones in the (a) Long-Chong uranium deposit, NW, NE, and EW, where uranium mineralization occurs. (b) The Huashan granite body linear structural strike rosette. (c) Schematic diagram of the geological structure of the Huashan rock mass.
Figure 11. A remote sensing linear structure interpretation of the Huashan rock mass: a, The three groups of tectonic altered granite vein zones in the (a) Long-Chong uranium deposit, NW, NE, and EW, where uranium mineralization occurs. (b) The Huashan granite body linear structural strike rosette. (c) Schematic diagram of the geological structure of the Huashan rock mass.
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Figure 12. Research area remote sensing image and structural interpretation analysis map group. (A) An ETM+ false color composite image of Huashan granite bodies. (B) An ETM+ false color composite image of Huashan granite bodies and their linear structure interpretation. (C) Rose diagram of the linear structural range of Huashan granite bodies.
Figure 12. Research area remote sensing image and structural interpretation analysis map group. (A) An ETM+ false color composite image of Huashan granite bodies. (B) An ETM+ false color composite image of Huashan granite bodies and their linear structure interpretation. (C) Rose diagram of the linear structural range of Huashan granite bodies.
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Table 1. Statistical details of the REE composition analysis results of the main drilling holes in the study area.
Table 1. Statistical details of the REE composition analysis results of the main drilling holes in the study area.
Sample NumberAnalysis Result ωB/10−6Notes
La2O3CeO2Pr6O11Nd2O3Sm2O3Eu2O3Y2O3Gd2O3Tb4O7Dy2O3Ho2O3Er2O3Tm2O3Yb2O3Lu2O3REO
ZH01179.60211.8036.11122.3022.473.22123.2020.503.6519.153.7610.181.8910.651.55770.04Ore
ZH02180.90187.4037.29123.5022.272.63103.9018.373.1416.443.218.861.689.581.40720.56
ZH03183.20205.4036.60124.1023.072.90125.0020.373.7019.873.8310.161.8710.211.52771.79
ZH04188.60200.6036.99123.1022.942.84132.9020.573.8820.744.1011.142.0711.561.69783.71
ZH05164.90217.6032.97110.5020.792.43100.8017.353.0916.573.218.861.679.611.40711.74
ZH06207.80211.7042.19141.6025.483.18133.6021.733.8320.584.1711.482.2913.091.92844.64
ZH07137.40186.4027.4091.8616.281.9387.6913.892.4613.092.667.451.438.151.19599.29
ZH08137.40213.2027.2991.3616.391.9985.3914.582.4913.372.647.061.417.921.18623.66
ZH09166.90215.8033.19111.1019.812.50109.3017.643.2217.023.449.561.8110.611.53723.43
ZH10179.20224.0035.89119.8022.172.79119.8019.723.4919.133.7610.331.9911.381.64775.09
ZH11179.70240.6036.07120.3021.622.69107.0019.193.2817.223.389.421.7510.021.46773.71
ZH12170.90216.3034.18114.1021.622.66118.6018.923.4018.303.6710.101.9411.201.65747.52
ZH13158.50218.8031.26103.4017.942.0788.4115.112.4813.372.657.531.468.641.24672.86
ZH14199.70205.2038.97127.9022.802.69117.7019.423.3217.873.579.861.9411.161.66783.76
ZH15150.50197.3030.28101.8018.062.04106.5016.082.9115.853.188.971.7910.431.57667.26
ZH16179.00210.6036.05120.8022.092.57120.2019.063.3918.283.7410.442.1111.961.81762.09
ZH17171.50214.6033.84112.9020.252.43103.4017.683.0416.143.259.201.7610.331.54721.85
ZH18183.20212.4036.93122.6022.122.47110.7018.423.2817.533.439.631.8710.851.62757.05
ZH19170.80196.4034.88117.6021.262.38117.6018.423.3217.673.589.711.9911.311.68728.60
ZH20198.60236.8040.91136.1024.172.85123.6020.913.6519.603.8610.752.1312.231.79837.95
ZH21175.30228.8036.13119.7021.682.48108.0018.573.1516.883.409.481.8310.751.58757.72
ZH22144.70226.4029.92100.0018.032.0887.6015.862.6614.112.827.841.528.841.28663.66
ZH23161.10231.2032.90110.8020.072.33108.1017.513.1016.533.339.571.8310.821.54730.73
ZH24165.50220.5033.74114.4020.632.62103.4017.803.1716.573.329.161.7710.151.46724.17
ZH25169.20214.4034.44117.6020.802.62103.1017.903.0616.093.208.851.679.631.41723.98
ZH26144.80215.0030.03101.1018.232.2197.7016.112.7415.092.958.351.599.181.41666.48
ZH01106.4029.4021.6268.3412.401.7681.3314.302.1911.522.386.690.885.100.70365.01Mixed initial products
ZH02131.6030.5027.0784.8114.941.7472.0514.912.2211.162.196.040.784.580.63405.20
ZH03141.3036.5028.7991.3117.202.1697.8418.562.8915.163.018.241.046.180.83470.99
ZH04138.8031.0527.1384.6015.631.8499.7617.502.7914.793.008.381.056.170.86453.35
ZH0589.1728.6918.4557.7710.321.0955.4410.591.618.401.654.550.583.450.47292.22
ZH06124.9024.0925.0177.4913.721.7684.0815.142.2311.992.477.110.945.570.78397.28
ZH0781.5725.0616.8452.499.121.0157.269.401.457.951.624.540.603.490.48272.86
ZH0862.9623.1913.1140.697.220.7044.137.691.156.131.223.360.422.420.33214.70
ZH0994.1324.0419.0359.4010.711.2470.4111.611.819.932.025.800.764.590.63316.11
ZH10100.6020.0120.0462.2011.001.3171.5911.831.789.571.985.500.693.920.54322.56
ZH11101.3022.6720.1062.1411.031.2765.9611.751.769.551.905.360.704.080.56320.12
ZH12113.7027.0522.9571.9512.971.6482.6214.032.2011.832.436.900.905.360.73377.26
ZH1394.0423.9419.2659.5910.091.1458.5310.131.548.411.754.950.664.080.55298.65
ZH14136.7019.2026.2381.0214.081.8081.2214.862.2411.982.487.140.955.610.78406.28
ZH1599.4424.9420.2062.9211.341.2176.1311.941.9410.752.256.520.895.560.74336.76
ZH16112.3021.1722.3669.2712.281.4483.4113.042.0611.332.386.950.955.750.80365.49
ZH1791.2521.1617.7854.069.351.0357.229.621.457.861.624.580.603.540.49281.61
ZH18140.3025.1527.2483.3414.581.6978.2414.332.2412.062.447.080.955.650.80416.08
ZH19118.0021.0624.0474.6013.591.5182.2213.872.1411.462.346.740.905.420.74378.61
ZH20114.6021.5423.0873.0612.561.4873.9512.711.9510.492.195.990.835.060.70360.19
ZH2189.0025.2918.4957.199.991.0958.4910.371.578.551.755.010.684.040.56292.07
ZH2273.1125.8014.9746.778.080.8247.448.301.266.941.393.900.522.970.41242.66
ZH2386.9124.2117.8255.129.721.0964.4710.231.608.971.845.330.714.310.58292.92
ZH2496.6928.3719.5861.6111.111.2664.9011.181.719.261.875.290.714.110.57318.22
ZH25103.2021.9420.9364.9111.281.3865.3211.431.709.041.855.150.683.950.55323.30
ZH2669.3624.0014.6245.928.020.8953.528.321.317.211.484.180.533.210.45243.01
Table 2. Characteristics of the ore bodies.
Table 2. Characteristics of the ore bodies.
Ore Body NumberDistributionProject (Unit)Ore Body Length (m)Ore Body Width (m)Ore Thickness and Coefficient of ChangeGrade and Coefficient of Change (Full Phase)Total Phase Oxide REE
Resources (t)
Peel RatioOre Body Morphology and Main Characteristics
Exploration Line
Intervals
See the Old Mine ShaftSee Mine Drill HolesMin–MaxCoefficient of Change (%)Min–MaxCoefficient of Change (%)
Area of DistributionConstruction of Old WellsConstruction DrillingAverage (m)Average (m)
071–8046207240012001.00–14.0067.630.020–0.24048.914715.160.18The ore body is generally distributed in a north-west to south-east direction, and the plane shape of the ore body is irregular and “ham-like”. The profile is predominantly layered.
The North East Side of Beicao Village472504.630.090
080–80160489310028001.00–21.5076.120.012–0.45248.0823,061.180.35The ore body is mainly oriented in a north–south direction and distributed in blocks.
From Beicao Village South to Tanggong Village North1725524.780.082
1030–78438910005501.00–17.0071.500.017–0.23246.502144.430.19The ore body is generally distributed in an east–west direction, with a triangular plane.
Tanggong Village East and Nearby451085.470.094
1261–991017710006001.00–22.8078.060.018–0.24043.042885.120.16The ore body is distributed in an east–west direction, forming a “diamond shaped” distribution.
Tanggong Village and Shuangtoudong Village101945.930.081
135–792325422006501.00–19.5067.970.016–0.36455.124986.290.22
From Shuangtoudong Village to Chetian Line North243046.260.084
140–9991575420023000.70–22.8074.300.016–0.34943.1917,341.700.09The ore body is generally distributed in a north–south direction, with a flat “diamond shaped” distribution.
From Shuangtoudong Village to Gongfu Village976524.820.077
Table 3. Chemical composition of the main rock phases of granite near the mining area.
Table 3. Chemical composition of the main rock phases of granite near the mining area.
NameNumber of SamplesIndexChemical Content (%)
SiO2TiO2Al2O3Fe2O3FeOMnOMgOCaONa2OK2OP2O5H2O+H2OCO2
Transition phase26Range value69.62–75.260.13–0.4812.76–15.010.39–1.270.57–2.670.02–0.060.19–0.870.64–
1.79
2.70–3.344.90–5.860.07–0.120.50–0.780.00–0.180.04–0.23
average value71.950.3313.90.821.620.050.51.193.085.280.10.660.080.12
Marginal phase3Range value72.42–76.320.05–0.3312.47–13.780.51–0.800.30–1.770.01–0.050.06–0.510.68–1.302.96–3.505.24–5.620.002–0.0590.30–0.620.02–0.200.093–0.19
average value73.80.2113.330.681.160.030.291.033.055.450.0310.460.110.14
Supplementation period6Range value73.44–77.160.05–0.1212.74–14.690.31–1.000.06–0.600.01–0.040.08–0.390.12–0.672.46–3.564.70–5.640.1150.420.060.19
average value75.110.0913.630.610.360.020.20.213.015.29
Table 4. The rare earth oxide content of magmatic rock in the mining area (unit:%).
Table 4. The rare earth oxide content of magmatic rock in the mining area (unit:%).
Sample NoTotal Phase Rare Earth ContentLeaching Phase Rare EarthLeaching RateDescription
YK70700.0300.00237.67Six original rock formations were collected in the entire mining area to form six ore samples, which were weathered and showed significant changes in composition.
YK11310.0670.007711.49
YK211490.0860.00202.33
YK411430.0820.008710.61
YK621520.0150.000090.60
YK680880.0250.000281.12
average0.0510.00355.64
Table 5. Ore material composition and REE content scale.
Table 5. Ore material composition and REE content scale.
Sampling PlaceSampling Depth (m)Sample Weight (kg)Sample Grade (%)DetritalClayey
Proportion of Sample (%)REO (%)Proportion of REO Content in Sample (%)Proportion of Sample (%)REO (%)Proportion of REO Content in Sample (%)
QJ11.00200.15157.720.10544.7542.280.17755.25
3.00200.16972.370.13863.0027.630.24437.00
5.00200.18076.720.14964.9523.280.26535.05
QJ25–6200.08572.070.06552.4627.930.15247.54
10–11200.07182.560.05559.8017.440.17540.20
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Zou, Z.; Zhang, S.; Yuan, J.; Ying, X.; Tao, Z.; Luo, S. Sustainable Exploration, Mining, and Utilization of a Rare Earth Deposit in Southeastern Guangxi: Insights into Metallogenic Regularity. Sustainability 2025, 17, 2552. https://doi.org/10.3390/su17062552

AMA Style

Zou Z, Zhang S, Yuan J, Ying X, Tao Z, Luo S. Sustainable Exploration, Mining, and Utilization of a Rare Earth Deposit in Southeastern Guangxi: Insights into Metallogenic Regularity. Sustainability. 2025; 17(6):2552. https://doi.org/10.3390/su17062552

Chicago/Turabian Style

Zou, Zhiyou, Sheng Zhang, Jinfu Yuan, Xin Ying, Zhongyi Tao, and Shunshe Luo. 2025. "Sustainable Exploration, Mining, and Utilization of a Rare Earth Deposit in Southeastern Guangxi: Insights into Metallogenic Regularity" Sustainability 17, no. 6: 2552. https://doi.org/10.3390/su17062552

APA Style

Zou, Z., Zhang, S., Yuan, J., Ying, X., Tao, Z., & Luo, S. (2025). Sustainable Exploration, Mining, and Utilization of a Rare Earth Deposit in Southeastern Guangxi: Insights into Metallogenic Regularity. Sustainability, 17(6), 2552. https://doi.org/10.3390/su17062552

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