Mineral Exploration Research Articles

Multi-stage magmatic fluid recharge and fluid mixing developed the Gongdongchong intermediate-sulfidation type epithermal Pb-Zn deposit, North Huaiyang, China: Constraints from petrography, fluid inclusion and in situ geochemistry studies of sphalerite

The Gongdongchong (GDC) lead and zinc deposit is located in the North Huaiyang (NHY) metallogenic belt, northern part of the Dabie orogen. Its Pb-Zn orebodies are predominately in the breccia pipe hosted by the Early Paleozic Foziling Group. Three stages of mineralization could be divided according to replacement relationships and petrography, and the ore and gangue mineral assemblages at the main base metal stage were recognized as combination of Fe-poor sphalerite + galena + pyrite + chalcopyrite + tetrahedrite with quartz and calcite. Three successive generations of sphalerite were distinguished through detailed petrographic observation on crystal-scale, namely Spc (core), Spm (mantle), and Spr (rim). Fluid inclusion petrography result shows that two-phase liquid-rich fluid inclusions are the dominant type in sphalerite. Microthermometric results show the homogenization temperatures and salinities of Spc ranged from 233 °C to 268 °C and 6.6 to 10.4 wt% NaCl equiv. While fluid inclusions in the Spm display homogenization temperatures of 241 °C to 284 °C, with salinities of 8.7 to 11.3 wt% NaCl equiv. This increasing trend may imply a magmatic fluid recharging from core to mantle. However, fluid inclusions in the Spr have homogenization temperatures of 231–254 °C, with salinities of 6.3–9.1 wt% NaCl equiv. A trend of mixing with meteoric water is manifested by the decrease of temperatures with decreasing salinities from mantle to rim. It suggests the combination of the magmatic fluid recharging and mixing of meteoric water should be the key mechanism responsible for the sphalerite precipitation at the GDC deposit. Meanwhile, the GDC deposit shows a similar range of homogenization temperatures and salinities with typical intermediate-sulfidation epithermal deposits, and these homogenization temperatures also correspond well with the geological thermometer results acquired by trace element concentrations of sphalerite. In addition, the sphalerite geochemical results obtained from trace elements as Mn, Co, In and Ge illustrate that the GDC Pb-Zn deposit shares a good consistence with epithermal Pb-Zn deposit.Based on the evidences presented above, combined with the geological and geochemical features, the GDC deposit can be classified as an intermediate-sulfidation epithermal deposit. Intermediate-sulfidation epithermal deposits usually share spatial and genetic relationships with porphyry deposits. This may provide new implication for the mineral exploration of porphyry deposits at depth in the NHY metallogenic belt.

Establishment of an Efficient and Rapid Regeneration System for a Rare Shrubby Desert Legume Eremosparton songoricum.

Eremosparton songoricum (Litv.) Vass. is a rare and extremely drought-tolerant legume shrub that is distributed in Central Asia. E. songoricum naturally grows on bare sand and can tolerate multiple extreme environmental conditions. It is a valuable and important plant resource for desertification prevention and environmental protection, as well as a good material for the exploration of stress tolerance mechanisms and excellent tolerant gene mining. However, the regeneration system for E. songoricum has not yet been established, which markedly limits the conservation and utilization of this endangered and valuable desert legume. Assimilated branches derived from seedlings were cultured on several MS mediums supplemented with various concentrations of TDZ or 6-BA in different combinations with NAA. The results showed that the most efficient multiplication medium was MS medium supplemented with 0.4 mg/L 6-BA and 0.1 mg/L NAA. The most efficient rooting medium was WPM + 25 g/L sucrose. The highest survival rate (77.8%) of transplantation was achieved when the ratio of sand to vermiculite was 1:1. In addition, the optimal callus induction medium was MS + 30 g/L sucrose + 2 mg/L TDZ + 0.5 mg/L NAA in darkness. The E. songoricum callus treated with 100 mM NaCl and 300 mM mannitol on MS medium could be used in proper salt and drought stress treatments in subsequent gene function tests. A rapid and efficient regeneration system for E. songoricum that allowed regeneration within 3 months was developed. The protocol will contribute to the conservation and utilization of this rare and endangered desert stress-tolerant species and also provide a fundamental basis for gene functional analysis in E. songoricum.

Advanced Processing of 2D Marine Reflection Seismic Data Using the Common Reflection Surface (CRS) Stack Method with K-L Filter Application

Data processing using the seismic reflection method is an important stage in the exploration of natural resources and minerals. This research was conducted to determine the effective and efficient stacking and filtering methods in reconstructing the subsurface geological structure of the earth from the results of data processing using ProMAX software. The data processing method used is the conventional stack and the Common Reflection Surface (CRS) stack. Aperture values of 0 ms – 50 m and 3000 ms – 150 m in the CRS stack process produce the most optimum seismic sections. Both methods produce a different quality of seismic cross-section display. The 2D cross-section model from the conventional stack method looks noisier than the results from the CRS stack method. In addition, the reflector pattern on the cross-section of the results of the CRS stack method is clearer and visible with a relatively large amplitude compared to the results of the conventional stack method. To maximize the quality of data display, data enhancement is applied, which is the K-L filter. The eigenimages value of 0.10% on the K-L filter with a horizontal window width of 120 is used to reduce random noise. Thus, an increase in the S/N ratio will be obtained in the seismic data so that the 2D cross-sectional model of the seismic reflection method can approach the original conditions of the subsurface geological structure.

Prediction of Au-Polymetallic Deposits Based on Spatial Multi-Layer Information Fusion by Random Forest Model in the Central Kunlun Area of Xinjiang, China

In recent years, there has been a growing emphasis on combining intelligent prospecting algorithms, such as random forest, with extensive geological and mineral data for the purpose of quantitatively predicting exploration geochemistry. This approach holds significant importance for enhancing the accuracy of target delineation. The central Kunlun area in Xinjiang possesses highly favorable ore-forming geological conditions, offering excellent prospects for mineral exploration. However, the depletion of shallow deposits coupled with a decade-long gap in geological exploration have presented increasing challenges in the quest to discover substantial metal resources. Consequently, there is now a severe shortage of reserve assets in the region, prompting an urgent need for the implementation of new theories, methods, and technologies in mineral resource investigation and evaluation efforts. The researchers used geological and regional geochemical data to construct a random forest metallogenic discriminant model for predicting the mineralization of gold polymetallic minerals in the central Kunlun area of Xinjiang and delineating the metallogenic target area. Two different sampling methods were compared to quantitatively predict gold polymetallic mineral resources. The results indicate that the selected training samples offer higher prediction accuracy and reliability by fully capturing the complex information of the original data. The random forest model using select training samples has valuable applications in metallogenic prospect prediction and potential division due to its ability to consider the actual exploration cost and identify small areas with high potential and a high proportion of ore. This study significantly improves prediction accuracy, reduces exploration risk, and expands the use of machine learning algorithms in mathematical geology in the central Kunlun area of Xinjiang.

Prediction of Au-Associated Minerals in Eastern Thailand Based on Stream Sediment Geochemical Data Analysis by S-A Multifractal Model

Conducted within the scope of geochemical exploration in eastern Thailand, this study aims to detect geochemical anomalies and potential mineral deposits. The objective was to interpret intricate spatial dispersion patterns and concentration levels of deposit pathfinder elements, specifically arsenic (As), copper (Cu), and zinc (Zn), using a comprehensive array of stream sediment geochemistry data. Methodologies involved integrating multifractal properties and traditional statistics, facilitated by the GeoDAS and ArcGIS platforms as instrumental analytical tools. In total, 5376 stream sediment samples were collected and evaluated, leading to the development of an in-depth geochemical map. The results indicated distinct geological units marked by substantially elevated average values of the aforementioned elements. Identification of geochemical anomalies was achieved through the spatial distribution method and the subsequent application of the spectrum-area (S-A) multifractal model. An intriguing link was found between high As concentrations and gold deposits in the area, suggesting As as a viable pathfinder element for gold mineralization. The anomaly maps, generated from the stream sediment data, spotlighted potential zones of interest, offering valuable guidance for future mineral exploration and geological inquiries. Nonetheless, it is vital to recognize that the increased values noted in these maps may be influenced by regional geological factors, emphasizing the necessity for a diverse set of analytical methods for accurate interpretation. This study’s significance lies in its pioneering use of the S-A multifractal model in geochemical data analysis. This innovative approach has deepened our comprehension of geochemical dispersion patterns and improved the precision of mineral exploration.

Kebijakan Dana Pemberdayaan 1% PT. Freeport Indonesia kepada Suku Amungme dan Kamoro Melalui LPMAK

Customary rights owners, investors and the state are working groups that must uphold the principles of justice in PTFI's mining business, the state, the Amungme and Kamoro communities are working partners in mining exploration in Mimika, Papua. Profit sharing between parties I, II and III is regulated in a humane work agreement and no injustice should occur. However, the problem is that customary landowners only receive a partnership trust budget (social budget), which varies annually. For example, from 1994-2003 or 23 years of existence, the social budgeting distribution from PTFI amounted to 1.3 billion US dollars (managed by LPMAK). Partnership budget distributions of $634 and $662 million also occurred (managed by PTFI's Non Community Affair Dept.). Trust and partnership budget reached USD 437.3 in 2006 and 2007 increased to USD 480.3 also distributed by PTFI. Decreased, reaching USD 400.0 in 2010. This research has both academic and practical purposes. It is useful for socially just budget distribution. Then, the methodology used is descriptive qualitative. Data collection was done through direct and indirect interviews. Samples, data analysis and management were conducted on the Amungme and Kamoro tribes as customary rights owners in Mimika, Papua. Research findings; PTFI, the state, the Amungme and Kamoro communities are not good partners in the mining business in Mimika, Papua.

Critical Minerals in the Context of Canada: Concepts, Challenges and Contradictions

Increased use of renewable energy, coupled with electrification of the economy, is considered important in efforts to limit future climate change. This energy transition is predicted to increase demands for some commodities, many of which are now labelled as critical mineral. The quest for such commodities is now a persistent theme for the resource industry and emerging government policies. This review for non-specialists explains several key concepts but also explores some challenges and apparent contradictions in the context of Canada. Canada now has a list of 31 critical minerals, but this includes some major commodities for which domestic production is significant and supply risk is low. The differences between our list and those of other jurisdictions reflect our more specific definitions. Most other commodities on Canada’s list are also identified by other countries and some are specifically linked to the energy transition. These include cobalt, lithium, manganese, nickel, graphite and vanadium (used in electric vehicle batteries and static energy storage), rare earth elements (REE; used for magnets in EV motors and wind turbines) and some rarer elements (e.g. germanium, gallium, indium and tellurium) used in photovoltaic (solar) energy systems. Some of these are potential primary products (e.g. lithium, graphite and REE) but many others (e.g. cobalt, platinum group elements and the photovoltaic elements) are byproducts from the production of major commodities, notably nickel, copper and zinc. The REE represent coproducts that are closely associated in nature and very hard to separate from each other; they are produced as a group. There are some specific challenges in exploring for and developing critical mineral resources. The end-use technology driving demand evolves on a timescale of years, but mineral exploration and development now typically take multiple decades. Material substitutions and unpredictable developments in technology complicate the exact prediction of future demands. The forecasts of overall relative demand growth are impressive, but for some key commodities global production will remain small in absolute terms, which may limit the potential for new discoveries. Simple measures of grade and tonnage are not always guarantees of viability, because deposits of some commodities (e.g. the REE) are mineralogically complex. Byproduct commodities cannot be produced in isolation, and many of these are only extracted in smelting and refining. Domestic production of these commodities is effectively lost if concentrates are exported for processing. The emissions and environmental impacts associated with production of critical mineral resources will also become important if such activity is to be linked to wider climate goals. This may present challenges in northern Canada, where renewable or low-carbon energy options are limited. Most draft Land Use Plans in the north presently emphasize large-scale land conservation, which could limit future exploration access before resource potential is fully assessed. Given the strong divisions of opinion about resource development, especially in the north, controversy and polarized debate will not easily be avoided. There are no simple answers to challenges that are political or jurisdictional rather than technical, but there is definitely a need for more public geoscientific information. This will help to identify areas of greatest potential, evaluate known deposits and contribute to future sustainable development. For many of the commodities on our critical mineral resources list, data for Canada remains incomplete, especially in more remote regions that are generally considered to have the highest potential.

Logistic regression for predicting the location of vegetable vendors in the city of Raipur, Chhattisgarh, India

Urban planning plays a pivotal role in guaranteeing the functionality, accessibility, and adaptability of cities to meet the needs of their diverse population and various official and informal economic activities. The primary objective of this work is to investigate the application of machine learning techniques in the identification of optimal places for vegetable vendors within the urban context of Raipur City, India. While logistic regression has been used in previous studies to address issues such as soil erosion, land susceptibility mapping, and identifying potential sites for health facilities and mining exploration, this model has yet to be applied to determining suitable locations for vegetable vendors. This gap in research could be beneficial if addressed, particularly in India, where many city residents rely heavily on vegetable vendors for their dietary needs. The paper’s main focus is on evaluating the reliability of the model and encouraging its implementation in similar scenarios, highlighting its efficiency and adaptability, which are also evaluated in this study. A stratified random sampling technique was implemented to collect data from four different regions of Raipur City. Subsequently, the gathered data was subjected to analysis employing the logistic regression machine learning technique, with the objective of making predictions. The results obtained from the analysis were highly impressive, as the model successfully predicted 44 out of the total 50 locations with an accuracy rate of 88%.

Mineral prospectivity modelling to delineate potential areas for gold deposits: a case study of Lupa Goldfield, South West Tanzania

ABSTRACT This study used the weight of evidence model to delineate prospective areas for gold deposits in the Lupa Goldfield. The method establishes a spatial relationship between known mineral deposits and evidential maps to create a mineral prospectivity map. Four evidential maps derived from geochemical, geological, geophysical, and topographical Digital Elevation Model (DEM) datasets were analysed and integrated to create a mineral prospectivity map. Results have revealed five classes ranked from the highest, high, medium, low, and lowest favourability patterns with probability values of 0.051, 0.0426, 0.0225, 0.0172, and 0.0091, respectively. The highest favourable areas have the best gold potentials based on the presence of predictor patterns from all four evidential maps. The posterior probability map revealed good prediction, existing gold deposits, such as Saza Mine and Shanta Gold Mine, were mapped. Results have shown that the weight of evidence model was successful and can be applied in mineral exploration targeting.

Mineral exploration and the green transition: Opportunities and challenges for the mining industry

In order to fulfill the rising demand for minerals to support global economic growth and create a sustainable future, the mining sector must simultaneously overcome hitherto unheard-of obstacles. In the framework of the green transition, this study discusses the advantages and disadvantages of mineral prospecting. We look at the years between 2015 and 2022 and concentrate on a sustainable mining model that takes into consideration the economic, social, and environmental effects of mineral exploration by employing CS-ARDL model. Our study is based on an examination of the mining sector in the Asian region, which is expanding quickly and making the transition to a greener economy. We highlight five significant findings from our study. First, by delivering the minerals required for low-carbon and renewable energy technologies, mineral exploration may be a key component of the green transition. Second, in order to lessen its influence on the environment, the mining sector must embrace sustainable practices and technology. Third, for mining operations to be successful, community involvement and social permission to operate are essential. Fourth, mining corporations are being held to higher standards of sustainability by financial institutions. Finally, technical advancements like big data and artificial intelligence may help the mining business remain viable.Overall, this research underscores how crucial it is for the mining sector to strike a balance between environmental, social, and economic goals. Mineral exploration must embrace sustainable techniques to be relevant in a world that is changing quickly. The green transition offers both possibilities and problems.

Geology, mineralogy, and alteration of the Cu-Pb veins, and their significance in mineral exploration: A case study in the Khajeh-Nezam area, SE Iran

Khajeh-Nezam area is situated within the Bam 1:100,000 geological sheet, SE Iran. The area was the subject of silt geochemical studies and consists of highly prospective Cu, Pb, Ba, and Fe veins and veinlets that demonstrate a northwest-southeast trend. A total of 149 silt samples were collected from the area and analyzed for 7 elements (As, Cu, Mo, Pb, Zn, Sb, Ba) using Inductively Coupled Plasma-Optical Emission Spectrometry. Univariate-multivariate statistical analysis the majority of variables demonstrate a distribution that is slightly too moderately positively skewed, which can be accurately explained using a log-normal model. Only Cu, Zn, and Pb demonstrate a normal distribution. The number-size (N-S) fractal model show that. The variables can be classified into two main groups. The first group comprises the main ore-forming elements, namely Cu, Ba, As, and Sb, which are associated with the epithermal system. On the other hand, Mo, Pb, and Zn demonstrate a stronger affiliation with vein and veinlet mineralization that could be linked to the margin of a possible hidden porphyry system. The geochemical halo in the southwestern part of the study area, which overlaps with volcanic rocks, has experienced significant alterations attributed to local intrusions, leading to a level of modification. A secondary weak anomaly, of relatively lesser significance, is observed in Pb, Zn, and Mo. Although these elements are not the primary constituents of the ore, they serve as pathfinder elements in marginal copper porphyry. The results obtained from the study have been utilized to identify concealed ore bodies using the classes defined by N-S classification model. Fieldwork conducted in the area confirms the presence of Fe oxide veins and veinlets that contain copper mineralization, along with carbonate Pb and Cu minerals. Various types of alteration have been identified, including argillic alteration accompanied by quartz and hematite in the vicinity of the veins and veinlets. The findings serve as probable evidence for the existence of a new copper porphyry system in the study area.

An Environmental Impact Framework for the Construction Stage of Municipal Solid Waste Landfill Mining: A Study on Piyungan Landfill in Indonesia

At present, the predominant method of urban waste management in Yogyakarta is centered around landfill disposal, resulting in a swift depletion of available capacity, notably at the Piyungan landfill site. Consequently, the exploration of landfill mining, a process that entails the retrieval of fully decomposed waste, is being contemplated as a potential alternative. Nevertheless, the execution of this initiative may give rise to environmental consequences. The objective of this study is to establish a comprehensive framework for assessing the ecological consequences of landfill mining operations in the initial stage of construction. The methodology encompasses a preliminary stage known as scoping, wherein potential impacts are identified and significant hypothetical impacts are assessed. Subsequently, a thorough assessment is conducted to examine the potential significant effects of the hypothetical scenario. This evaluation involves a detailed analysis of the various environmental elements and parameters associated with each activity that may serve as a potential source of impact. The present analysis employs a straightforward matrix and a flow chart. The assessment indicates that the implementation stage of landfill mining has the potential to generate substantial hypothetical effects on multiple facets of the environment, encompassing physical, chemical, biological, socio-economic, and cultural dimensions. The potential impacts encompass various factors such as air pollution, gas explosions, reduced surface air quality, odor problems, and unfavorable public attitudes and perceptions. These impacts collectively contribute to the overall consequences of the situation.

A Practical Approach to Constructing a Geological Knowledge Graph: A Case Study of Mineral Exploration Data

A Practical Approach to Constructing a Geological Knowledge Graph: A Case Study of Mineral Exploration Data

Mitigation of Mining Effects on the Environment

Editor’s note: The aim of the Geology and Mining series is to introduce early career professionals and students to various aspects of mineral exploration, development, and mining in order to share the experiences and insight of each author on the myriad of topics involved with the mineral industry and the ways in which geoscientists contribute to each. Abstract All human activities produce waste and affect our environment, including the solids and water involved during mining and metallurgical operations. The nature and characteristics of these impacts vary considerably depending on many factors, including the geology of the operation, type of mining and processing implemented, sensitivity of the local environment to the operation, and proximity to human settlements or sensitive environmental settings. Environmental challenges associated with mineral extraction and processing include impacts to land, air, water, soil, flora, fauna, and socioeconomic fabric. Mines can generate large land disturbances and can also result in sterilization of land through deposition of barren, nonreactive rock piles (termed waste) during production and after operation. Other mine waste piles can be chemically reactive and interact with precipitation and runoff, leading to metal and sulfate release into surface and ground water. Impacts on soils may result directly from weathering of mine waste or through interaction with affected waters. Interaction with the atmosphere may occur, with release of aerosol or airborne metals or minerals affecting air quality. In addition, the release of gases containing CO2, SOx, and NOx and halide gases can lead to acid rain or general lowering of air quality. These challenges can be predicted, quantified, and understood during the mine design and operations processes by application of geologic knowledge, geochemical and hydrogeological data, and mining experience. Such understanding can then identify appropriate solutions, including changes to operations through sequenced mining to reduce exposure of material with high metal or sulfide content; partial or full backfill of mine excavations; use of cemented waste backfill; modifications to water discharge designs; and treatment of water prior to discharge. A critical aspect of addressing environmental challenges and reducing environmental impact involves engagement with communities, government, and society. The confidence of society is essential to the delivery of long-term sustainable plans.

Study on the detection technology and response of isolated anomalous bodies in transient electromagnetic wave logging of formations

Transient electromagnetic wave logging is one of the key methods for detecting underground formations, especially for identifying anomalies near wells using higher frequencies and resolutions. In this paper, the 3D TDFD (three-dimensional time-domain finite-difference) simulation method is used to investigate the detection technique of wellbore anomalies based on the scattered field of transient electromagnetic waves and its significance in underground structure identification and localization. The research results show that isolated anomalies can be effectively characterized by extracting the scattering field response generated by block-shaped anomalies while eliminating the contribution of background media. Analyzing the measurement response caused by scatterers provides important information about the position, size, and response magnitude of the anomalies, offering an effective method for detecting and identifying wellbore anomalies. Applying this detection technique enriches the existing methods for wellbore anomaly detection, providing important theoretical and technical foundations for petroleum and solid mineral exploration, as well as the construction of underground defense engineering.

The Role of Non-Arctic Powers in the Arctic Geopolitical Space

The Arctic region is increasingly emerging as a pivotal factor in the geopolitical landscape of international relations. It serves as an arena where the interests of major global powers converge, encompassing vast mineral reserves, territorial disputes, and the ongoing development of the Northern Sea Route. Arctic nations are establishing frameworks for cooperation and regional development, resulting in the creation of international organizations such as the Arctic Council and the formulation of comprehensive programs for the sustainable development of northern territories. This article aims to assess the involvement of non-Arctic powers in the development of the Arctic. Notable emerging actors include the People’s Republic of China, India, South Korea, Japan, and the European Union. Our examination reveals their significant contributions to economic development, the establishment of scientific centers focused on ecological research and climate change, as well as mineral exploration. Furthermore, this research raises important questions regarding the legal status of the Arctic seas, particularly those through which commercial vessels navigate. In the foreseeable future, potential scenarios involve further modifications to the institutional governance of the Arctic region, an expansion of the Arctic Council’s authority and membership, and the negotiation of new international legal agreements to facilitate cooperative interstate development in the Arctic based on effective and trust-based partnerships.

Mapping of the Structural Lineaments and Sedimentary Basement Relief Using Gravity Data to Guide Mineral Exploration in the Denizli Basin

The Aegean Graben System is a complex tectonic structure in Western Anatolia and the Denizli Graben is a member of this system that hosts many geothermal springs, ore deposits, and travertine areas. In this study, the gravity data were analyzed to determine the subsurface geological structures and the depth model of the basin. The Bouguer gravity anomaly has a NW–SE pattern that is consistent with the general trend of the Denizli Basin. The pre-Neogene basement depths range from 0.1 km to 2.3 km. The Denizli Basin is composed of the Çürüksu Basin and the Laodikia sub-basin. The basins have undulated structures with many depressions; the deepest depression region is in the northern part of the Çürüksu Basin, which is close to the Pamukkale Fault Zone. In addition, the new gravity lineament map was obtained by using new-generation edge detection techniques: the tilt angle of the horizontal gradient amplitude (TAHG), and fast sigmoid-edge detection (FSED) of gravity data. The new proposed lineament map shows that the Denizli Basin has complex structures consisting of NW–SE, E–W, and NE–SE trending lineaments, and the major NW–SE trending faults and NE–SW trending lineaments control the main structural configuration. The uplifts and depressions in the basin deposit and the intersection area of lineaments are promising prospective areas for mineral deposits and have energy resource potential.

Integration of in‐mine seismic and GPR surveys to gain advanced knowledge of Bushveld Complex orebodies

AbstractImproving the exploration of deep‐seated mineral deposits and assessing the stability of the mine pillars require that geophysical techniques are deployed in a fast and cost‐effective manner with minimal environmental impact. This research presents results from in‐mine reflection seismic experiments and a ground penetrating radar (GPR) survey conducted at the Maseve platinum mine, South Africa. The research aims to develop and implement methods to image platinum group metal (PGM) deposits and geological structures near mine tunnels and assess the stability of pillars. The seismic experiments were conducted using a sledgehammer source (10 lb), conventional cabled geophones (14 Hz), and a landstreamer with 4.5 Hz vertical component geophones. The GPR survey was conducted using a Noggin 500 GPR system with 500 MHz centre frequency. An image of the underlying orebody and geological structures down to 100 m from the mine tunnel floor (∼500 m below ground surface) was produced. We correlated the coherent reflections beneath the tunnel floor with a known Upper Group (UG2) PGM orebody. The final seismic section shows that the UG2 mineralisation is dissected by near‐vertical dykes, faults and fractures. These structures, faults in particular, are interpreted to have been active post‐mineralisation, implying that they may have contributed to the current complex geometry of the deposit. Four GPR profiles were collected around a stability pillar adjacent to the seismic lines. The radargram sections were processed to improve the signal‐to‐noise ratio (S/N). The results show different patterns of fracturing and stress‐induced structures. These fractures were shown to be sub‐vertical and, possibly, constitute complex micro‐structures within the pillar, which could compromise the pillar stability and integrity. The study demonstrates that in‐mine seismic and GPR surveys can be cost‐effective and valuable for mineral exploration.

The REE-Zr-U-Th Minerals of the Maronia Monzodiorite, N. Greece: Implications on the Saturation and Segregation Mechanisms of Critical Metals in Intermediate–Mafic Compositions

This work delves into the presence of REE-Ti-Zr-U-Th minerals, in the mafic–intermediate rocks of the Maronia pluton, Greece, an Oligocene intrusion formed through arc-magmatism during subduction. In Maronia monzodiorite, critical metals are contained in three principal mineral groups, namely, the REE-Ti-Zr, REE-Ca-P, and U-Th assemblages. The REE-Ti-Zr group includes REE-ilmenite, chevkinite-like phases, zirconolite, and baddeleyite. The REE-Ca-P assemblage is represented by allanite-(Ce), monazite-(Ce), and huttonitic monazite-(Ce). The U-Th assemblage comprises thorite–coffinite and uraninite–thorianite solid solutions. The paragenetic sequencing of these minerals offers insights into their formation conditions and correlation with the pluton’s magmatic evolution. In the REE-Ti-Zr group, mineral formation progresses from REE-ilmenite to baddeleyite through chevkinite-like phases and zirconolite under oxidizing conditions. The REE-Ca-P sequence involves allanite-(Ce), followed by monazite-(Ce), late allanite-(Ce), and huttonitic monazite-(Ce). In the U-Th group, earlier thorite–coffinite phases are succeeded by uraninite–thorianite solid solutions, indicating Si-undersaturation at late magmatic stages. Fluctuations in Ca-activity induce alternating formations of allanite-(Ce) and monazite-(Ce). These mineral variations are attributed to early-stage interactions between high-K calc-alkaline and shoshonitic gabbroic melts, influencing critical metal enrichment and mineral speciation. The study’s insights into paragenesis and geological processes offer implications for mineral exploration in analogous geological settings.

A Multi-Objective Approach for Optimizing the Layout of Additional Boreholes in Mineral Exploration

Accurate subsurface exploration requires an optimal network of boreholes. This paper proposes a multi-objective approach to optimize the layout of additional exploratory boreholes. In order to illustrate this approach, geochemical analyses of core samples at the eastern part of the Kahang copper deposit, Central Iran, were used. A measure of the grade uncertainty (kriging standard deviation) and a confidence measure on the ore/waste classification were first calculated by implementing ordinary and indicator kriging. An ore value function was then determined to measure the total value of each block by considering the grades of all the effective variables and their ore membership degree derived from a fuzzy treatment of the grades. Finally, a misclassification cost is defined for each block based on the expected economic effects of ore loss and waste dilution. As a result, an index for the selection of additional boreholes was introduced in order to maximize the kriging standard deviation, the ore misclassification cost, and the ore value and to minimize the confidence measure. Applied to the Kahang copper deposit, this index allowed the prioritization of areas for infill sampling, leading to the recommendation for eight vertical and two directional additional boreholes.