Search Results (7)

Mineral exploration in the Iberian Pyrite Belt follows increasingly deeper targets. The present study introduces an innovative methodology for the detection and identification of blind metallic mineral deposits, in particular volcanogenic massive sulfides based on surface rock coatings. This approach follows the identification pathways of upward metal escape routes and metal distribution in rock fractures located in different anisotropic or isotropic planes above the Neves-Corvo VMS deposit ore lenses, using VP-SEM-EDS and XRD. Coatings are dominated by poorly crystalline to amorphous phases, with goethite and birnessite as the main Fe- and Mn-bearing minerals. Copper, zinc and lead are systematically enriched in coatings developed above or near the ore bodies, reflecting chalcopyrite, sphalerite and galena acidic leaching. Tin shows a restricted and heterogeneous distribution, while Ni and Co display no systematic relationship with the ore bodies. Barium and late Ba–Pb–(Zn) mineralization along fault zones record VMS mineralization. Lead isotopic coating signatures overlap those of IPB massive sulfide deposits, confirming a dominant VMS-derived contribution. Fe–Mn coatings were formed by precipitation from ascending meteoric fluids that leached metals from massive sulfides, their alteration halos, and surrounding lithologies, preserving the geochemical footprint of buried mineralization. This approach constitutes a new patented exploration tool. Full article

Magmatic nickel–copper–platinum group element (PGE) deposits hosted in mafic–ultramafic intrusions within volcanic arc systems are highly attractive targets for mineral exploration, yet their genesis remains poorly understood. This study investigates metagabbroic intrusions in the Paleoproterozoic Lynn Lake greenstone belt of the Trans-Hudson Orogen to identify the key factors, in the original gabbros, that control the formation of magmatic Ni-Cu-PGE deposits in volcanic arc systems. By examining the field relationships, geochemical and sulfur and oxygen stable isotope compositions, mineralogy, and structural fabrics, this study aims to explain why some intrusions host mineralization (e.g., Lynn Lake and Fraser Lake intrusions), whereas others remain barren (e.g., Ralph Lake, Cartwright Lake, and Snake Lake intrusions). Although both the fertile and barren gabbroic, likewise original, intrusions exhibit metaluminous, tholeiitic to calc-alkaline affinity with volcanic arc geochemical signatures, they differ significantly in shape, ranging from vertical and tube-like to tabular forms, reflecting distinct geological settings and magma dynamics. The gabbroic rocks of fertile intrusions exhibit erratic trace element profiles, lower (Nb/Th)_N and higher (Cu/Zr)_N ratios, as well as a larger range of δ³⁴S values than those in barren intrusions. Key factors influencing Ni-Cu-PGE mineralization include the degree of partial melting of the mantle, early sulfide segregation, and crustal contamination, particularly from volcanogenic massive sulfide deposits. These processes likely triggered sulfide saturation in the mafic magmas. Geochemical proxies, such as PGE concentrations and sulfur and oxygen stable isotopes, provide critical insights into these controlling factors. The results of this study enhance our understanding of the metallogenic processes responsible for the formation of magmatic Ni-Cu-PGE deposits in the gabbroic intrusions emplaced in an extensional setting due to slab rollback, during the geological evolution of the Lynn Lake greenstone belt, offering valuable guidance for mineral exploration efforts. Full article

Phytoremediation, a sustainable approach, is a hot topic, particularly for harsh mining environments. The Baiyin copper mine, a typical example of massive sulfide deposits, retains value as a national park after closure. Our research on it aimed to explore phytoremediation. By studying the plant community’s phyto-sociological attributes, we found that plants maintained long-term stability, with restoration potential. And the top-level dominant species, Lycium chinense and Nitraria tangutorum, were selected as candidate repair plants based on importance value. Then, we assessed soil heavy metals using pollution indices and found that Pb, As, and Cd were the primary contributors, along with Cu and Zn, causing pollution. Next, we determined the repair ability of two candidate repair plants through their accumulation effect and transport efficiency, finding that both had strong tolerance to these heavy metals and accumulated similar amounts, except for Cu, which was slightly lower than expected; however, Lycium compensated for this with its higher Cu conversion rate, leading to its final recommendation. Lycium has an uncommon advantage: during extraction of active ingredients, it can remove heavy metals as impurities, preserving economic value. This discovery provides the idea, theoretical basis, and pioneer plant for the phytoremediation of sulfide deposits like the Baiyin copper mine, particularly in northwestern China’s mining regions. Full article

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

Its properties make copper one of the world’s most important functional metals. Numerous megatrends are increasing the demand for copper. This requires the prospection and exploration of new deposits, as well as the monitoring of copper quality in the various production steps. A promising technique to perform these tasks is Laser Induced Breakdown Spectroscopy (LIBS). Its unique feature, among others, is the ability to measure on site without sample collection and preparation. In this work, copper-bearing minerals from two different deposits are studied. The first set of field samples come from a volcanogenic massive sulfide (VMS) deposit, the second part from a stratiform sedimentary copper (SSC) deposit. Different approaches are used to analyze the data. First, univariate regression (UVR) is used. However, due to the strong influence of matrix effects, this is not suitable for the quantitative analysis of copper grades. Second, the multivariate method of partial least squares regression (PLSR) is used, which is more suitable for quantification. In addition, the effects of the surrounding matrices on the LIBS data are characterized by principal component analysis (PCA), alternative regression methods to PLSR are tested and the PLSR calibration is validated using field samples. Full article

Fusion and analysis of thematic information layers using machine learning algorithms provide an important step toward achieving accurate mineral potential maps in the reconnaissance stage of mineral exploration. This study developed the Neuro-Fuzzy-AHP (NFAHP) technique for fusing remote sensing (i.e., ASTER alteration mineral image-maps) and geological datasets (i.e., lithological map, geochronological map, structural map, and geochemical map) to identify high potential zones of volcanic massive sulfide (VMS) copper mineralization in the Sahlabad mining area, east Iran. Argillic, phyllic, propylitic and gossan alteration zones were identified in the study area using band ratio and Selective Principal Components Analysis (SPCA) methods implemented to ASTER VNIR and SWIR bands. For each of the copper deposits, old mines and mineralization indices in the study area, information related to exploration factors such as ore mineralization, host-rock lithology, alterations, geochronological, geochemistry, and distance from high intensity lineament factor communities were investigated. Subsequently, the predictive power of these factors in identifying copper occurrences was evaluated using Back Propagation Neural Network (BPNN) technique. The BPNN results demonstrated that using the exploration factors, copper mineralizations in Sahlabad mining area could be identified with high accuracy. Lastly, using the Fuzzy-Analytic Hierarchy Process (Fuzzy-AHP) method, information layers were weighted and fused. As a result, a potential map of copper mineralization was generated, which pinpointed several high potential zones in the study area. For verification of the results, the documented copper deposits, old mines, and mineralization indices in the study area were plotted on the potential map, which is particularly appearing in high favorability parts of the potential map. In conclusion, the Neuro-Fuzzy-AHP (NFAHP) technique shows great reliability for copper exploration in the Sahlabad mining area, and it can be extrapolated to other metallogenic provinces in Iran and other regions for the reconnaissance stage of mineral exploration. Full article

Fault systems are characteristically one of the main factors controlling massive sulfide mineralization. The main objective of this study was to investigate the relationship between fault systems and host lithology with massive sulfide copper mineralization in the Sahlabad area, South Khorasan province, east of Iran. Subsequently, the rose diagram analysis, Fry analysis, lineament factor (LF) map analysis and multifractal technique were implemented for geological and geophysical data. Airborne geophysical analysis (aeromagnetometric data) was executed to determine the presence of intrusive and extrusive masses associated with structural systems. Accordingly, the relationship between the formation boundaries and the fault system was understood. Results indicate that the NW-SE fault systems are controlling the lithology of the host rock for copper mineralization in the Sahlabad area. Hence, the NW-SE fault systems are consistent with the main trend of lithological units related to massive sulfide copper mineralization in the area. Additionally, the distance of copper deposits, mines and indices in the Sahlabad area with fault systems was calculated and interpreted. Fieldwork results confirm that the NW-SE fault systems are entirely matched with several massive sulfide copper mineralizations in the area. This study demonstrates that the fusion of lineament factor (LF) map analysis and multifractal technique is a valuable and inexpensive approach for exploring massive sulfide mineralization in metallogenic provinces. Full article