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17 pages, 8754 KiB

Open AccessArticle

Integrating Magnetic and Self-Potential Methods for Efficient Graphite Exploration: Insights from Ji’an, Northeast China

by Junchen Liu, Jiwei Yi, Chuncheng Li and Ci Gao

Minerals 2025, 15(1), 27; https://doi.org/10.3390/min15010027 - 28 Dec 2024

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Abstract

Graphite, known for its exceptional electrical and thermal conductivity as well as its lubricating properties, is a critical mineral resource for various industrial applications. Due to these unique properties, graphite has gained increasing importance across various technological and industrial fields. Northeast China, rich [...] Read more.

Graphite, known for its exceptional electrical and thermal conductivity as well as its lubricating properties, is a critical mineral resource for various industrial applications. Due to these unique properties, graphite has gained increasing importance across various technological and industrial fields. Northeast China, rich in graphite deposits, faces significant exploration challenges owing to dense vegetation and limited bedrock exposure. This study provides a comprehensive analysis of the geological strata in the region, utilizing magnetic exploration to identify ore-forming strata beneath the Quaternary sediment. Additionally, self-potential methods were used to delineate areas of potential graphite mineralization. The effectiveness of these methods was evaluated across two well-tested and thoroughly studied geological profiles. The magnetic anomaly revealed three magnetic anomaly areas, with the low magnetic anomaly zone associated the Huangchagou Formation, indicating strong potential for graphite ore. Then, a self-potential survey was conducted across this anomalous zone, revealing a nearly east–west trending banded anomaly, suggesting the presence of graphite deposits. Trenching and drilling operations were subsequently carried out, confirming the existence of graphite ore, with total reserves exceeding 50,000 kt. This research demonstrates that the combination of magnetic surveys and self-potential methods offers a cost-effective geophysical approach for graphite exploration. These methods provide a promising strategy for discovering graphite deposits, particularly in the challenging terrains of Northeast China. Full article

(This article belongs to the Special Issue Advances in Magnetic and Electromagnetic Techniques for Mineral Exploration: Enhancing Resource Discovery)

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14 pages, 5051 KiB

Open AccessArticle

Exploration of the Subsurface Three-Dimensional Structure in Rare Earth Ore Areas Using Electrical Resistivity Tomography: A Case Study in Changting, Fujian, China

by Yingchun Tang, Ping Liu, Shujing Jia, Yang Yang, Yajun Mo and Jie Zhu

Minerals 2024, 14(11), 1164; https://doi.org/10.3390/min14111164 - 17 Nov 2024

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Abstract

The development of fracture zones (broken zones) and underground karst rivers in underlying granite can significantly reduce the recovery rate of ion-adsorption-type rare earth ores. Additionally, leaching solutions flowing along unfavorable geological formations can lead to environmental pollution. Therefore, investigating the development of [...] Read more.

The development of fracture zones (broken zones) and underground karst rivers in underlying granite can significantly reduce the recovery rate of ion-adsorption-type rare earth ores. Additionally, leaching solutions flowing along unfavorable geological formations can lead to environmental pollution. Therefore, investigating the development of fracture zones (leakage channels) in granite basements is of great significance. In Changting, Fujian, China, several methods have been used in exploration areas (C1 and C2) to study the characteristics of rare ores. This study has focused on the stratigraphic and structural characteristics of the C2 exploration area. Twelve exploration profiles were designed to collect data using electrical resistivity tomography, and a deep electrical structure model of the study area was obtained through inverse calculations. The results indicated that the exploration profiles effectively delineated the thickness of the weathered granite layer and the spatial distribution characteristics of the deep-seated fault structures, which were consistent with the drilling results within the study area. These findings provide important reference materials for the assessment of ion-adsorption-type rare earth ore reserves, blocking leakage channels, and the layout of recovery tunnels. Full article

(This article belongs to the Special Issue Advances in Magnetic and Electromagnetic Techniques for Mineral Exploration: Enhancing Resource Discovery)

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15 pages, 9366 KiB

Open AccessArticle

Study of the Genesis Process and Deep Prospecting Breakthrough in the Gouli Ore Concentration of the East Kunlun Metallogenic Belt Using Audio Magnetotelluric Data

by Ji’en Dong, Peng Wang, Hua Li, Huiqing Zhang, Mingfu Zhao, Haikui Tong, Xiaoliang Yu, Jie Li and Binshun Zhang

Minerals 2024, 14(9), 930; https://doi.org/10.3390/min14090930 - 12 Sep 2024

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Abstract

The East Kunlun Orogenic Belt is an essential part of the Qin-Qikun composite orogenic system, the most crucial orogenic belt in Qinghai Province, and an important gold ore-producing area in China. The Gouli gold field in its eastern section is one of the [...] Read more.

The East Kunlun Orogenic Belt is an essential part of the Qin-Qikun composite orogenic system, the most crucial orogenic belt in Qinghai Province, and an important gold ore-producing area in China. The Gouli gold field in its eastern section is one of the most important gold fields discovered in the belt in recent years. The Mailong mining area is an important gold mining area in the Gouli ore-concentrated area. The area has experienced frequent and intense magmatic activity, with intrusive rock bodies extensively exposed and intersected by a complex network of fault structures, providing excellent geological conditions for the formation of gold deposits. However, it is difficult to explore due to high altitude, poor transportation, and shallow coverage. This study used an audio magnetotelluric sounding method to track the deep direction and inclination of known mineral belts in the Mailong mining area, and identified mineral exploration targets, providing a basis for mineral exploration. Subsequently, a gold ore body was discovered through drilling verification, achieving a breakthrough in deep mineral exploration. The electromagnetic exploration method works well for exploring structurally altered rock-type gold deposits in plateau desert areas, and combined with the results of this electromagnetic exploration, a metallogenic geological model and genesis process of the Mailong mining area has been constructed. Full article

(This article belongs to the Special Issue Advances in Magnetic and Electromagnetic Techniques for Mineral Exploration: Enhancing Resource Discovery)

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21 pages, 5593 KiB

Open AccessFeature PaperArticle

Moment Estimation from Time Domain Electromagnetic Data

by Marc A. Vallée and Mouhamed Moussaoui

Minerals 2024, 14(9), 888; https://doi.org/10.3390/min14090888 - 30 Aug 2024

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Abstract

Moment representations have been proposed to facilitate the interpretation of geophysical time domain electromagnetic responses. We present a new methodology for estimating these moments from field data for different system waveforms when on-time and off-time measurements are available. Quadrature impulse response moments are [...] Read more.

Moment representations have been proposed to facilitate the interpretation of geophysical time domain electromagnetic responses. We present a new methodology for estimating these moments from field data for different system waveforms when on-time and off-time measurements are available. Quadrature impulse response moments are estimated by a recursive relation involving moments of the input waveform and moments of the observed response. After adapting this method to time domain electromagnetic applications—in particular, MEGATEM and AeroTEM (AirTEM) airborne electromagnetic systems—we present the results from applying this method on synthetic and real data collected over the Reid–Mahaffy test site in northern Ontario, Canada. Full article

(This article belongs to the Special Issue Advances in Magnetic and Electromagnetic Techniques for Mineral Exploration: Enhancing Resource Discovery)

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21 pages, 12899 KiB

Open AccessArticle

Location Prediction Study of Fluorite Ore in Shallow Cover Area: Evidence from Integrated Geophysical Surveys

by Liu Cheng, Li Han, Yang Kai, Gao Yongbao, Tang Weidong and Yao Chuan

Minerals 2024, 14(8), 838; https://doi.org/10.3390/min14080838 - 19 Aug 2024

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Abstract

The Beishan region is a vital fluorite metallogenic belt in northwest China, characterized by favorable geological conditions for fluorite mineralization. However, being located in the Gobi Desert and affected by shallow cover layers, only a few outcrops can be observed on the surface. [...] Read more.

The Beishan region is a vital fluorite metallogenic belt in northwest China, characterized by favorable geological conditions for fluorite mineralization. However, being located in the Gobi Desert and affected by shallow cover layers, only a few outcrops can be observed on the surface. Therefore, comprehensive geophysical research is necessary to locate and predict regional metallogenic potential and the spatial distribution of veins beneath the cover. This study conducted a combination of ground magnetic method (GM), induced polarization (IP) surveys, portable gamma-ray (PGR), portable X-ray fluorescence analyses (PXRF), and audio Magnetotelluric (AMT) to conduct comprehensive exploration. The IP and GM effectively identified concealed ore-bearing space distributions and ground PGR- and PXRF-constrained mineralization anomalies, while AMT surveys constructed deep electrical structure models for ore deposits. This approach delineated concealed fluorite deposit locations as well as potential magmatic–hydrothermal migration pathways. Engineering verification confirmed the effectiveness of this method combination. This study established a comprehensive geological–geophysical positioning prediction technique that can serve as a reference for locating and predicting fluorite deposits in shallow-covered areas within the Gobi Desert. Full article

(This article belongs to the Special Issue Advances in Magnetic and Electromagnetic Techniques for Mineral Exploration: Enhancing Resource Discovery)

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14 pages, 5127 KiB

Open AccessArticle

Deep Geological Structure Analysis of the Dongyang Area, Fujian, China: Insights from Integrated Gravity and Magnetic Data

by Zhenyu Zhang, Yongbo Li, Liang Chen, Qiang Zhang and Yue Sun

Minerals 2024, 14(8), 837; https://doi.org/10.3390/min14080837 - 19 Aug 2024

Viewed by 607

Abstract

To explore the deep geological structure of the Dongyang area in Fujian, China, gravity data from the area and its surroundings were collected and processed. Additionally, a high-precision magnetic survey was conducted in the Zhongxian region of this area, with subsequent analysis of [...] Read more.

To explore the deep geological structure of the Dongyang area in Fujian, China, gravity data from the area and its surroundings were collected and processed. Additionally, a high-precision magnetic survey was conducted in the Zhongxian region of this area, with subsequent analysis of the magnetic anomalies. Through the integration of regional geological data, a comprehensive analysis was carried out on the characteristics of gravity–magnetic anomalies and deep geological structures in the Dongyang area. The study indicates that the primary portion of the Dongyang area lies southwest of the expansive circular volcanic structure spanning Dehua to Yongtai. Two significant residual gravity anomalies were identified within the region, interpreted as the Xiaoban-Shuangqishan and Dongyang-Lingtouping residual gravity-positive anomalies. In the Zhongxian region, the magnetic field exhibits complexity with notable amplitude variations. Positive anomalies predominate in the western and northern sectors, while localized positive anomalies are prominent in the eastern region. The central area portrays a circular and disordered mix of positive and negative anomalies. Particularly distinctive are the band-shaped and fan-shaped negative anomalies curving from northeast to southeast through the central region. Various positive and negative anomalies of varying strengths, gradients, and orientations overlay both positive and negative magnetic backgrounds in specific locales. Moreover, the Dongyang area showcases well-developed fault structures, primarily oriented in northeast and northwest directions. Leveraging the regional magnetic attributes in conjunction with regional geological data, 39 faults were deduced in the Zhongxian region of the Dongyang area, delineating three promising mineralization zones. Full article

(This article belongs to the Special Issue Advances in Magnetic and Electromagnetic Techniques for Mineral Exploration: Enhancing Resource Discovery)

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16 pages, 17436 KiB

Open AccessArticle

Airborne Natural Total Field Broadband Electromagnetics—Configurations, Capabilities, and Advantages

by Alexander Prikhodko, Andrei Bagrianski and Petr Kuzmin

Minerals 2024, 14(7), 704; https://doi.org/10.3390/min14070704 - 11 Jul 2024

Viewed by 1207

Abstract

The airborne electromagnetic system MobileMT exploits natural fields in a broadband frequency range with offset measurements of magnetic and electric field variations. It was introduced in 2018 and has since been developed in various configurations, each tailored to meet the demands of different [...] Read more.

The airborne electromagnetic system MobileMT exploits natural fields in a broadband frequency range with offset measurements of magnetic and electric field variations. It was introduced in 2018 and has since been developed in various configurations, each tailored to meet the demands of different exploration tasks, varied terrains, and geoelectrical conditions and support time-domain data with controlled primary field sources. There are four distinct airborne systems: the original MobileMT; the lighter configuration, MobileMTm; the configuration for a drone carrier, MobileMTd; and the innovative time-domain AFMAG hybrid, TargetEM. The paper describes the technical features of each system, their differences and inherent strengths, the optimal usage conditions, and insights into their applications under different conditions across various exploration tasks. Several field case studies are provided to support the natural field electromagnetics capabilities of recovering geological structures in a wide depth range, beginning from the near surface, and address the impact of parasitic IP effects on time-domain data. Full article

(This article belongs to the Special Issue Advances in Magnetic and Electromagnetic Techniques for Mineral Exploration: Enhancing Resource Discovery)

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16 pages, 7506 KiB

Open AccessArticle

Application of Integrated Geological and Geophysical Surveys on the Exploration of Chalcedony Deposits: A Case Study on Nanhong Agate in Liangshan, China

by Shengping Gong, Keqiang Zhao, Mingming Wang, Shengwu Yan, Yong Li and Jianzhou Yang

Minerals 2024, 14(7), 677; https://doi.org/10.3390/min14070677 - 28 Jun 2024

Cited by 1 | Viewed by 1046

Abstract

Nanhong agate, esteemed for its vivid color and natural shine, is experiencing a scarcity in supply despite its high demand. The primary deposits of agate, typically found near the surface, have not been extensively explored due to the predominance of traditional manual excavation [...] Read more.

Nanhong agate, esteemed for its vivid color and natural shine, is experiencing a scarcity in supply despite its high demand. The primary deposits of agate, typically found near the surface, have not been extensively explored due to the predominance of traditional manual excavation methods. This research examined the Nanhong agate deposits in the Zhaojue–Meigu region of Liangshan, China, employing the integration of geological and geophysical surveys. Field geological surveys allowed us to outline the general areas where agate is found. Following this, using magnetic surveys, vertical electrical sounding, and controlled-source audio magnetotellurics, agate deposits were located within the conglomerate layer of the second member of the Feixianguan Formation from the Lower Triassic period at depths of less than 100 m. Our results identify mineralized layers, Xuanwei Formation mudstone, and the underlying bedrock, thus supporting the creation of a mineral prediction map. This research provides essential insights and guidance for agate exploration and the development of associated mineral resources. Full article

(This article belongs to the Special Issue Advances in Magnetic and Electromagnetic Techniques for Mineral Exploration: Enhancing Resource Discovery)

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25 pages, 6929 KiB

Open AccessReview

Case Studies of Magnetic and Electromagnetic Techniques Covering the Last Fifteen Years

by Marc A. Vallée, Mouhamed Moussaoui and Khorram Khan

Minerals 2024, 14(12), 1286; https://doi.org/10.3390/min14121286 - 18 Dec 2024

Viewed by 867

Abstract

Magnetic and electromagnetic techniques have a long history of application in mineral exploration to detect deposits and their surroundings. Their implementation over the last fifteen years has been affected by strong variations in the mining market in parallel with important technological developments. During [...] Read more.

Magnetic and electromagnetic techniques have a long history of application in mineral exploration to detect deposits and their surroundings. Their implementation over the last fifteen years has been affected by strong variations in the mining market in parallel with important technological developments. During this period, both methods were the subject of numerous documented case studies all over the globe, which is a sign of popularity and longevity of these techniques. Through a review of case histories from the main geophysical journals, we analyze the principal usage of these methods when applied to mineral exploration, while the majority of documented cases originate from North America, Asia, and Australia. There are more case studies describing the use of the magnetic method and we attribute this popularity to direct and indirect use of this method for mineral exploration. In particular, there is an increasing number of magnetic surveys conducted with drones. Combining magnetic and electromagnetic techniques is also common. The number of magnetic and EM technique case histories range by descending order from gold, porphyry copper, polymetallic, massive sulfides, uranium, Ni-Cu-PGE, iron ore, kimberlite, and iron-oxide copper-gold, with a number of single continent-specific applications. Full article

(This article belongs to the Special Issue Advances in Magnetic and Electromagnetic Techniques for Mineral Exploration: Enhancing Resource Discovery)

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