Copper Mineralization Research Articles

Petrogenesis of the Hercynian Granite in the Shuangjianzishan Super‐large Ag Polymetallic Deposit, Inner Mongolia and its Metallogenic Significance: Evidence from Geochronology and Petrogeochemistry

AbstractThe Shuangjianzishan deposit is a typical magmatic‐hydrothermal deposit located in the southern Great Xing'an Range. Recent investigations have identified significant copper and tin mineralization at depth within the Shuangjianzishan deposit; however, the coupling relationship between magmatic emplacement and mineralization processes remains debated. This study presents whole‐rock geochemistry, zircon LA‐ICP‐MS U‐Pb dating, and zircon Hf isotope analyses of granite from the northern Shuangjianzishan deposit. The analysis results indicate the granite crystallized between 252.3 and 257.9 Ma, corresponding to Late Permian magmatic activity. The granite displays ɛHf(t) = 5.95‐14.87, and tDM2 = 333–900 Ma. Geochemically, the granite is rich in Si and Al, with high K, classified as a calc‐alkaline, weakly peraluminous rock. LREEs are enriched, while HREEs are depleted, and a slight negative Eu anomaly, all of which are consistent with A‐type granite characteristics. The Hercynian granite in the Shuangjianzishan deposit formed during the latter or post‐collisional stages of the collision orogeny following the closure of the Paleo‐Asian Ocean in the late Paleozoic era. The material source indicates a mixed origin, involving both crust and mantle contributions. The granite is also enriched in Cu, Pb, and Zn, suggesting its potential role as an ore‐forming material source for the Shuangjianzishan deposit. This study proposes a potential link between Hercynian magmatism and mineralization at the Shuangjianzishan deposit for the first time, suggesting that multistage metallogenesis may be a response to successive magmatic events from Hercynian to Yanshanian periods in the mining area.

Separation of iron and copper in skarn deposits from the Yueshan ore field, eastern China: The control of magma physicochemical conditions

Iron and copper mineralization in the Yueshan ore field is intricately linked to the Cretaceous Yueshan diorite intrusions, yet they frequently materialize as distinct deposits. Despite this, the key factors dictating the segregation of these metals remain poorly understood. To gain insights into the role of magma physicochemical conditions in this segregation, we conduct a comparative analysis of the U-Pb dating, whole-rock geochemistry, and mineral chemistry of the newly uncovered Zhuchong skarn iron deposit (Fe:Cu ratio = 197) and the Anqing skarn copper deposit (Fe:Cu ratio = 35), both situated within the Yueshan ore field of the Middle Lower Yangtze River Valley Metallogenic Belt (MLYB) in eastern China. The garnet U-Pb dating of the Zhuchong and Anqing deposits are 138.3 Ma and 137.2 Ma, respectively, which are consistent with the zircon U-Pb dating (138.3 Ma) of diorites from the Zhuchong and Anqing deposit. The emplacement of diorite intrusions and Fe-Cu mineralization occurred at 137 – 139 Ma, consistent with the Cu-polymetallic mineralization epoch (145 – 137 Ma) in the MLYB. The diorite samples from the Yueshan intrusion and the Zhuchong and the Anqing deposits exhibit typical characteristics of adakites, such as high Sr/Y (28 – 174) and (La/Yb)N (26 – 40), along with similar and enriched Sr-Nd (εNd(t) = − 7.95 ∼ − 7.33) and zircon Hf isotope (−14.9 ∼ − 6.4) compositions. This suggests that the magma source regions for the diorites from the three locations were all likely derived from the melting of sediment-rich subducted oceanic crust with the potential of copper mineralization. However, chemical compositions of zircon, apatite, and amphibole from diorites reveal that diorites in the Zhuchong and Anqing deposits were emplaced at different depth levels and physicochemical conditions. Specially, the diorite in the Zhuchong Fe deposit was emplaced at shallower levels (1.9 km), with higher oxygen fugacity (mean = ΔNNO + 1.9) and fluorine concentration (2096 ppm), water deficiency (3.3 ± 0.4 wt%), sulfur-poor conditions (avg = 494 ppm), lower pressure (49.2 MPa), temperature (746 ℃), and chlorine (945 ppm) concentration relative to the Anqing Cu deposit (Emplacement depth: 2.53 km; oxygen fugacity: ΔNNO + 1.5; F: 1720 ppm; H2Omelt: 3.9 ± 0.4 wt%; S: 816 ppm; P: 66.9 MPa; T: 778 ℃; Cl: 945 ppm).It is proposed that a shallower emplacement depth may have promoted extensive exsolution of magmatic fluids, leading to the outward migration of water, S, Cl, and Cu elements, which resulted in the high iron-copper ratio observed at the Zhuchong Fe deposit. This process could have led to the relative Cl-poor nature and smaller Cu size at the Zhuchong Fe deposit, as well as the widespread development of vein-type copper ore bodies in the region.

Southeastern extension of Singhbhum Shear Zone, Eastern Indian Shield: A detailed appraisal

Trans-crustal, northerly dipping, arcuate Singhbhum Shear Zone (SSZ) constituting the interface of Proterozoic North Singhbhum Mobile Belt (NSMB) and Singhbhum Craton (SC) is established over a strike length of about ∼200 km from Baharagorato Chakradharpur in the west beyond which it bifurcates around the wedge shaped Chakradharpur granite. Based on geological mapping and meso to micro scale structural analysis, present work examines the SSZ’s southeastern extension beyond Baharagora, indicating its southward continuation for about 50 km to Dubukidihi within the NSMB lithopackage. Bangriposi Shear Zone (BSZ) which defines the terrane boundary between the SC and NSMB in this sector, splays towards north as Bangriposi West Shear Zone (BWSZ) and both transects the Dhanjori Basin longitudinally. BSZ and BWSZ are interpreted to be cogenetic with SSZ. NSMB in this area comprises of pelitic and psamopelitic rocks intruded by mafic–ultramafic magmatism and granitoids. Considering a north to south compression regime during accretion of NSMB with SC, the study area, which forms the interface between the craton and mobile belt, is at an acute to obtuse angle with the direction of overall stress field. It is marked by several high strain zones characterized by N-S shear band cleavages with moderate easterly dips, and northerly pitching stretching/mineral lineation. Consistent westerly vergent folds on mylonitic plane and orientation of stretching lineation indicates top to WSW movement in the shear zones. Tectonically interleaved mafic–ultramafic schist within the Romapahari granite are sites of copper mineralization with enhanced nickel concentration pointing towards future exploration sites for epigenetic copper, uranium mineralization which is so characteristic of SSZ.

Processes controlling magma fertility at buenavista del cobre porphyry copper deposit (cananea, méxico): A new petrogenetic model based on zircon u-pb dating and apatite geochemistry

The Buenavista del Cobre is a world-class porphyry Cu-Mo deposit located in the Cananea Mining District, northern Sonora, México. Using zircon U-Pb dating, we show that the Proterozoic Cananea Granite, unconformably overlain regionally by Paleozoic limestones hosting skarn deposits underlies the present-day pit. We also present new crystallization ages for host rocks of copper mineralization in the District, dating for the first time a volcanic rock of the Henrietta Formation at 186.8 ± 1.1/3.0 Ma and the El Torre Syenite at 176.3 ± 1.1/2.9 Ma. Zircon U-Pb dating of the different porphyritic bodies reveals that the magmatic activity at Buenavista del Cobre lasted at least 4 Myr, from 59.7 ± 0.5/1.1 Ma to 56.1 ± 0.2/0.9 Ma. The deposit is composed by several porphyry intrusions referred to as “ore-rich” and “ore-poor” based on their individual metal contributions, which provides the opportunity to study the origin and processes enhancing magma fertility in an individual deposit. Combining our new geochronological dataset with geochemistry of apatite from the different porphyries allows us to propose a new petrogenetic model for the Buenavista del Cobre deposit. As the apatite Eu and Ce anomalies overlap with no clear difference between the ore-rich and ore-poor intrusions, we propose that the magmatic oxidation states of the magmas were similar. However, differences in apatite REE signatures, as well as variations in apatite Sr compositions between the two groups suggest that fractional crystallization processes in the parental magma influence the fertility of the porphyries. Additionally, apatite Cl contents of ore-rich porphyry intrusions are higher (>0.4 wt%) than the ore-poor intrusions (<0.2 wt%), suggesting an important role of the initial Cl content of the magmas in the mineralization process. These observations give new insights on the petrogenetic processes at origin of porphyry magma fertility. We propose that the evolution of the parental melt by fractional crystallization of hydrous minerals (hornblende) at upper crustal levels induced low H2O content of the residual magma, resulting in the formation of ore-poor porphyries. In contrast, we suggest that fractionation of anhydrous minerals (plagioclase) increased the H2O content in the residual melt, leading to the formation of ore-rich porphyries. Our new data allow us to propose an original genetic model for the Buenavista del Cobre deposit, which involves two cycles of supply, cooling and partial crystallization. This contribution shows that petrogenetic processes controlling porphyry copper magmas fertility are recorded in the composition of apatite at the deposit scale and highlights the importance of considering apatite geochemistry as an exploration tool.

Integrated remote sensing and geochemical studies for enhanced prospectivity mapping of porphyry copper deposits: a case study from the Pariz district, Urmia-Dokhtar metallogenic belt, southern Iran

Mapping hydrothermal alteration zones associated with porphyry copper deposits (PCDs) is crucial for identifying new exploration targets on a regional scale. Hydrothermal alteration indicator layers play a fundamental role in recognizing potential areas for PCDs, highlighting the need for precise delineation of these zones and their integration with geochemical and geological data to reduce uncertainty in mapping porphyry copper prospectivity. This study focuses on the Pariz district within the Urmia-Dokhtar Metallogenic Belt (UDMB) in southern Iran, a region known for its significant porphyry copper mineralization. First, logical operator algorithms (LOA) were applied to ASTER remote sensing data to map and distinguish argillic and phyllic alteration zones associated with PCDs. Subsequently, propylitic alteration zones associated with chlorite-epidote and propylitic alteration associated with calcite were also delineated, as were silica-rich hydrothermal alteration zones. Five evidence layers corresponding to these geologic features were generated and weighted with logistic functions, independent of expert judgment and without consideration of the spatial distribution of known mineral occurrences (KMOs). In addition, two layers of information were developed, including multivariate geochemical signatures and proximity to intrusive rocks. The geochemical analysis identified two significant factors associated with porphyry copper mineralization: Factor-I (Zn, Pb, Cu, Sn, B) and Factor-II (Mo, Cu). These factors contributed to a multivariate geochemical signature in addition to the alteration layers derived from remote sensing. Evaluation using prediction- area (P-A) plots and Normalized density index (ND) confirmed the effectiveness of all seven layers for mineral prospectivity mapping (MPM). Geometric average (GA), data-driven index overlay (IO), and deep autoencoder neural network (DEA) integrated these layers, with IO showing superior performance in identifying high potential zones, as indicated by higher prediction rates compared to other methods. Therefore, IO proves to be the most efficient approach for mapping the regional porphyry copper minerals in the Pariz district of the UDMB.

The Chemerpil gravimagnetic anomaly as a modern reflection of the unique Precambrian volcanic-plutonic magnetite-gold mineralisation structure of the Ukrainian Shield (Middle Bug area)

The article is devoted to the peculiarities of genesis and mineralogical potential of Chemerpol iron-magnetite structure, its difference from other similar objects of Central Bug area. As an independent geological-geophysical object it was established according to the data of gravimetric and magnetometric survey of medium scale as a complex localised maximum of subisometric shape with diameter of 1.7 km and area of 2.8 km2. In regional structural and tectonic terms, this maximum is confined to the Sinitsiv block of the Golovanovsk suture zone. As of today, the Chemerpol structure has been sufficiently investigated by mapping drilling and various geophysical methods at the level of the crystalline basement surface. Based on the obtained data, the main petrophysical complexes involved in its structure have been determined. The industrial and mineralogical potential of the Chemerpolska structure is estimated at 100 million tons of magnetite quartzites and carbonate formations, as well as 2 tons of exogenous gold in the weathering crust. No estimates have been made of the underlying gold deposits. Copper mineralisation, represented by the natural copper, chalcopyrite and chalcosine, has been identified in the weathering crust and crystalline basement. By structural and tectonic features, petrophysical and mineralogical diversity, the Chemerpolska structure can be attributed to local pipe volcanic-magmatic objects. Its closest well-studied geological analogues may be such Precambrian "stratified" iron-oxide-gold-copper deposits as Solobot and others of the Carajas ore district in Brazil. For geological verification of new conclusions about the peculiarities of the Chemerpol structure and its actual ore potential, it is necessary to continue its study based, first of all, on the data of targeted structural exploration drilling and deep seismic and electrical exploration methods. The economic efficiency of extraction of the main mineral components of the Chemerpolska structure - gold and magnetite iron - can be increased due to the accompanying use of non-metallic calcifiers for the manufacture of sintering flux, soil deoxidation, raw materials for road pavement.

Substantial in situ Ti isotope variations in rutile record source and fluid evolution of porphyry copper mineralization systems

Titanium (Ti) and its stable isotopes have been widely used as tracers for magmatic processes. However, our understanding of Ti isotope behavior in magmatic-hydrothermal systems remains limited. Hence, the in situ Ti isotope composition (δ49Ti) of magmatic titanite and hydrothermal rutile associated with magnetite and chalcopyrite mineralization was determined for the first time in four well-characterized porphyry copper deposits in southern Tibet. The rutile formed through the alteration of primary Ti-rich minerals during fluid-rock interaction in the early high-temperature magnetite and later moderate-temperature chalcopyrite stages of mineralization. Hydrothermal rutile, altered from magmatic titanite, exhibits δ49Ti values similar to those of residual magmatic titanite. This suggests that hydrothermal rutile inherited the Ti isotope composition of magmatic titanite. The average δ49Ti values of rutile are negatively correlated with whole-rock εNd(t) and zircon εHf(t) data, and positively correlated with whole-rock (87Sr/86Sr)i values, which suggests that the initial Ti isotope compositions of hydrothermal rutile in porphyry copper deposits primarily reflect their source. Rutile from the Qulong deposit sometimes exhibits fractionation of δ49Ti at levels exceeding 0.5‰, displaying a negative correlation with Zr and FeO, which may be attributed to the formation of magnetite and rutile at an early potassic alteration stage. Isotopically light Ti is preferentially incorporated into magnetite and rutile. Thus, the rutile associated with sulfide mineralization that formed from the remaining fluids during a later stage of phyllic alteration is enriched in heavy δ49Ti. These findings contribute to the understanding of how rutile fractionates Ti isotopes in hydrothermal systems related to porphyry copper deposits. In local contexts, the substantial crystallization of magnetite, along with the preferential incorporation of isotopically light Ti during the early stages, leads to a decrease in oxygen fugacity within the ore-bearing fluid. This, in turn, facilitates the formation of sulfides during later stages. The results of this study demonstrate the efficacy of in situ Ti isotope analysis as a powerful tool for tracking fluid and metal sources, and can be used to help interpret ore precipitation throughout different stages of magmatic-to-hydrothermal ore-forming processes.

Clinopyroxenite-Wehrlite Porya Guba Complex with Fe-Ti-V and PGE-Cu-Ni Mineralization in the Northeastern Part of the Fennoscandian Shield: Evidence of Post-Orogenic Formation from Sm-Nd Isotope System

The Porya Guba clinopyroxenite–wehrlite complex is located in the core of the Lapland–Kola collisional orogen (~2.0–1.9 billion years old) in the northeastern part of the Fennoscandian Shield and contains iron–titanium–vanadium and nickel–copper mineralization with platinum group elements (PGEs). The controversial geological position of the complex within the mafic granulites of the Kolvitsa mélange (pre-, syn- or post-orogenic) is clarified by Sm-Nd isotopic dating of the rocks and mineralization. The Sm-Nd age of the barren clinopyroxenites that dominate the complex is 1858 ± 34 Ma (εNd(T) = −1.5) and is interpreted as the time of its emplacement as evidenced by a sample from the largest intrusion, named Zhelezny. This age is younger than that of the peak of granulite metamorphism in the host rocks (1925–1915 Ma) and coincides within error with the age of rutile from granulites (1880–1870 Ma), indicating the time at which cooling to 450 °C occurs. Emplacement in the cooled rocks is confirmed by the detection of quenching zones in clinopyroxenites around granulite xenoliths. Magnetite ores, as well as mineralized pyroxenites with sulfide disseminations, are formed during a late stage of the complex development, as suggested by active assimilation of granulite xenoliths by these rocks. The isotopic age of mineralized pyroxenites enriched in PGEs is 1832 ± 35 Ma (εNd(T) = –2.0), while the age of magnetite ores is 1823 ± 19 Ma (εNd(T) = –2.5). Thus, the obtained isotopic data indicate that the emplacement of the Porya Guba complex and probably other small mafic–ultramafic intrusions in the Kolvitsa mélange granulites took place after the end of the Lapland–Kola collision.

Evaluation of Cyanide Leaching Behavior of Typical Associated Copper Minerals in Gold Concentrates Based on Solution Chemistry and Interfacial Physicochemical Properties Analysis

Evaluation of Cyanide Leaching Behavior of Typical Associated Copper Minerals in Gold Concentrates Based on Solution Chemistry and Interfacial Physicochemical Properties Analysis

Mining and urbanization affect river chemical water quality and macroinvertebrate communities in the upper Selenga River basin, Mongolia (revised version).

Mongolia is a country with a quickly growing economy mainly based on the mining of gold, copper, coal, and other minerals. Mining, urbanization, and agriculture impact the water quality in the upper Selenga River basin in northern Mongolia, which is the center of the Mongolian economy. Previous measurements of pollution loads were alarming, but restricted to chemical measurements. Here, for the first time, we combine freshwater biomonitoring and laboratory water quality data across a broad gradient of water quality and land use intensity. We track the effects of different types of pollution on aquatic invertebrates and test their use as bioindicators. We collected water samples, environmental parameters, and macroinvertebrates at 36 sampling sites at the rivers of Tuul, Kharaa, and Orkhon and their tributaries Sugnugur, Boroo, Sharyn Gol, Gatsuurt, and Yeröö. PCA of catchment water quality distinguished three groups of pollutants prevalent at the sites, (1) nutrients, (2) salt ions(Cl-, Na+, Mg2+, So42-, Ca2+) and mining by-products (B, Sr, U, Mo), and (3) (heavy) metals, which often exceeded regulatory standards. We recorded a total of 59 macroinvertebrate taxa belonging to 31 families in seven insect orders plus Amphipoda and Gastropoda. Species diversity declined with higher impact. Five environmental factors structured macroinvertebrate community composition in RDA: elevation of sample location, site total nitrogen, dissolved oxygen, electrical conductivity, and water chemistry. We conclude that macroinvertebrate communities are an appropriate and inexpensive tool for monitoring water quality in Mongolia and suggest government action to establish a long-term monitoring program.

Tectonic Inversion in Sediment-Hosted Copper Deposits: The Luangu Area, West Congo Basin, Republic of the Congo

Complex Neoproterozoic tectonic processes greatly affected the West Congo Basin, resulting in a series of dispersed copper deposits in the Niari Sub-basin, Republic of the Congo. Structural observation and analysis can help in understanding both the transportation pathways for copper accumulation and the detailed tectonic evolution processes. This study examines cases from four copper mine sites in the Luangu region of the Niari Basin, using a set of codes that consider the three regional tectonic regimes (extension, extrusion, and contraction) and three deformation criteria (maximum effective moment criterion, tensile fracture criterion, and the Coulomb criterion). By combining these two aspects, nine new codes are introduced: the extension maximum effective moment criterion (EM), extension tensile fracture criterion (ET), extension Coulomb criterion (EC), strike-slip maximum effective moment criterion (SM), strike-slip tensile fracture criterion (ST), strike-slip Coulomb criterion (SC), compression maximum effective moment criterion (CM), compression tensile fracture criterion (CT), and compression Coulomb criterion (CC). By analyzing and applying these codes to the selected sites, we show that the new codes can present a geometric coordination catering to an exhumation-related inversion process from extension, strike-slipping, to contraction. The existence of SM- and CM-related structures that occurred during regional extrusional and contractional events may indicate a deeper level of exhumation for layers related to copper deposits in the field sites. A new tectonic evolution model is presented, considering the hypothesis of vertical principal stress changes while the two horizontal principal stresses remain relatively constant during copper mineralization affected by the Western Congo Orogen. The application of the nine codes facilitates the determination of interrelations between different tectonic regimes.

Paleotectonic setting of basaltoid volcano-plutonic belts with porphyry copper deposits

The article considers geotectonic position and geological features of basaltoid volcano-plutonic belts (VPBs) associated with porphyry copper and gold-copper deposits. Three types of the belts, the oceanic, perioceanic, and riftogenic ones, are distinguished among these VPBs. The oceanic and peri-oceanic belts were incorporated into the composition of ensimatic island arcs and formed at a late stage of their development, after inversion of the basaltoid troughs. The riftogenic belts appeared in island-arc oceanic settings at a late stage of filling the spreading zones. VPBs of the first two types with porphyry gold-copper deposits are located over the convergent boundaries of tectonic plates in an above-subduction position, while belts of the third type form extended linear zones within individual rift structures and contain smallscale porphyry copper objects with poor gold and molybdenum contents. As examples of the structures, the Sunda, Philippine archipelago, New British, Solomon, Alaska, and Antilles ensimatic island arcs and the Irendyk and Novoalekseevsky belts of rift zones of the Southern Urals are described. Volcanic-plutonic associations participating in the structure of these VPBs (including those productive for porphyry copper mineralization), as well as structural-lithological complexes of their basement, are characterized. It is noted that repeated magmatism manifestations during the long-term development of the ensimatic island arcs lead to appearance of several basaltoid VPBs with porphyry gold-copper deposits, while basaltoid belts with porphyry copper objects in the rift settings are formed only once.

Replacive IOCG systems in the Ossa Morena Zone (SW Iberia): The role of pre-existing ironstones as a geochemical trap

The central Ossa Morena Zone (SW Iberia) hosts a regionally extensive ironstone level interbedded with bimodal volcanic rocks, limestone and shale of Lower-Middle Cambrian age. The stratabound ironstone includes dominant magnetite and hematite with locally abundant chert and barite. It is interpreted as being (sub-)exhalative at or near the seafloor and formed during a rifting event that postdated the Cadomian orogeny. In some places, such as in the Las Herrerías deposit, the ironstone is irregularly replaced by a chalcopyrite-rich ore; the Cu-rich mineralization is accompanied by the pervasive phyllic alteration of the hosting siliciclastic sediments. The highest copper grades are found when the ironstone is crosscut by WNW-ESE-trending late-Variscan extensional brittle-ductile structures that are interpreted as the feeder channels for deep hydrothermal fluids. A similar nearby copper-rich mineralization (Pallares) is is likely controlled by the tectonic contact between limestone and pyrite-rich black shale.Sr-Nd whole-rock isotope geochemistry data suggests that the Sr in the ironstone (87Sr/86Sri ≈ 0.7088) is close to isotopic equilibrium with the local exhalative barite (0.7084–0.7086) and Cambrian seawater. The ironstone has a significantly more crustal εNd initial signature (<-1.8) than the coeval volcanic rocks (+5.2 to + 7.9). The younger sulfide mineralization inherited the Nd isotope composition of the ironstone but shows a significant enrichment in 87Sr (87Sr/86Sr > 0.7091) that is interpreted as related with the input of genetically different and more crustally-derived hydrothermal fluids.39Ar-40Ar dating of the phyllic alteration suggest that the copper mineralization was formed at ca. 332–330 My. These ages are coeval with those of small peraluminous granite intrusions that host Cu-Au vein-like mineralization and dated at 331.8 ± 1.6 Ma (LA ICPMS U-Pb zircon). Our interpretation is that the copper-rich mineralization at the Las Herrerías area is the distal expression of an intrusion-related hydrothermal system.Numerical modelling shows that ironstone is an effective trap for copper precipitation due to the large changes in pH and fO2 that take place when copper-bearing acid and reduced fluids react with the brittle ironstone. The precipitation of chalcopyrite, however, is controlled by the amount of available reduced sulfur in the ore trap. The δ34S values of the sulfides (+12.6 to + 21.6 ‰) suggest that the most likely source for the reduced sulfur is the thermogenic reduction of aqueous sulfate equilibrated with the exhalative barite (δ34S, +31.4 to + 35 ‰) with some minor input of reduced sulfur leached from the metasediments.This system could be considered as a variant of the IOCG clan. The formation of the ironstone and the copper mineralization, however, are separated by more than 200 My. Probably, many IOCG systems have a similar origin as Las Herrerías, with an ironstone being just a passive geochemical trap for the copper–gold mineralization.

Mineralogy and geochemistry of gold and copper mineralization, Sultan Anouch, Malayer, West Iran

Mineralogy and geochemistry of gold and copper mineralization, Sultan Anouch, Malayer, West Iran

Electrochemical Performance of Ti Gr. 2 as Electrodes in Contact with Saline Suspension of Clays during the Electroflotation Process

The presence of clays in copper minerals has a significant negative impact during their processing, leading to low recoveries during the flotation process. In saline environments, the presence of these clays promotes operational problems associated with salinity, leading to decreases in the copper concentrate grade, alterations in the rheology of the mineral pulp, reduction in the selectivity of copper during the flotation process, declines in the quality of clarified water, and excessive corrosion of metallic components. This study explores the electroflotation of kaolinite and montmorillonite clays in NaCl solutions using a modified Hallimond tube coupled with Ti Gr. 2 electrodes for bubble generation via water electrolysis and the corrosion analysis of these electrodes applying the superposition model. The electroflotation results show recovery of clays close to 72.68% for kaolinite, 88.44% for montmorillonite, and 67.36% for a mixture of both clays. The presence of clays helps reduce the corrosive effects of Ti Gr. 2 from 0.069 A/m2 in NaCl to 0.0073 A/m2 in NaCl with montmorillonite clay.

Bio-mediated enhancement of supergene copper mineralization: Evidence from Cu isotope geochemistry

The relationship between microbial activity and the supergene modification of ore systems has been a major subject of debate. Here, we present isotopic evidence of microbial-driven secondary copper mineralization in the active cementation zone of the Las Cruces deposit, a volcanogenic massive sulfide deposit located in Iberian Pyrite Belt, Spain. Copper isotopic data show that the lower isotopic ratios (δ65Cu ≈ −9.2 ± 0.11 ‰, the lowest value measured worldwide in a supergene environment) are found in the upper part of the cementation zone, the same zone where the maximum copper grades are found and where there is direct evidence of extremophilic microbial activity. There is a tendency towards higher values downwards through the cementation zone (−9.2 ± 0.11 ‰ to + 1.67 ± 0.11 ‰ δ65Cu) and upwards into the former Cu-depleted gossan that originally capped the cementation zone (−7.79 ± 0.11 ‰ to −1.32 ± 0.11 ‰ δ65Cu). As microbes preferentially sequester the lighter isotope when incorporating intracellular Cu, this distribution indicates that microbes played a major role in the formation of the high-grade zones. Water arrives to the deposit enriched in isotopically heavy copper, likely because it has leached other ore bodies upstream. δ65Cu values of water currently flowing into the system are remarkably more positive than those in the ore, indicating that microbial activity is a major cause of copper isotope fractionation. At least half of the copper transported by the incoming waters remains within the ore body. Our best interpretation is that the large and high-grade cementation zone at Las Cruces is of biogenic origin, and that the primary mineralization acted as a trap for copper transported by groundwater, leading to the formation of an exotic mineralization distal to sub-eroded massive sulfides located upstream.

A hybrid framework for Detection of Multivariate porphyry Cu Signatures and Anomaly Enhancement: Incorporation of SFA, GMPI, and Grey Wolf Optimization

Geochemical data from stream sediment are commonly employed for regional scale mineral exploration, as they can be utilized to detect geochemical anomalies associated with mineralization processes. However, recognizing efficient multielement geochemical signatures related to target mineralization using stream sediment geochemical data can be challenging due to the intricate nature of mineralization events. To achieve this goal, this article proposes a combination of statistics, logistic functions and machine learning techniques. Initially, the staged factor analysis (SFA) approach was applied to the data to determine the geochemical footprints associated with porphyry copper mineralization in the Varzaghan area. Subsequently, the geochemical mineralization probability index (GMPI) was utilized to facilitate appropriate separation, more precise identification, and the transfer of data into a fuzzy space. By using a combination of SFA and GMPI, it was feasible to enhance the detection of geochemical halos and concealed anomalies. Ultimately, the output of these two approaches was subjected to an improved clustering technique known as GWO-K-means to detect geochemical anomalies. The findings indicated that there is a strong relationship between known mineral occurrences (KMOs) and the identified anomalous areas. The success rate curve demonstrated that the optimized model outperformed the K-means model, proposing that optimization can boost the accuracy in identifying geochemical targets. Overall, the outcomes of this study can be beneficial for proper planning of future exploration activities.

Lithophysical characteristics of productive strata of cupriferous sandstone within Zhezkazgan ore district in the Central Kazakhstan

Purpose. The paper concerns additional geological appraisal and identification of extra localization criteria of cupriferous mineralization of a stratiform type. The research is intended to define physical and geological factors influencing sandstone distribution within the north-end of Zhezkazgan synclinal in the Central Kazakhstan. Methods. A complex analysis of geological and mineralogical, geophysical, and geochemical data was carried out relying upon the information obtained from deep-hole wells. Modern methods to process and interpret the field data were applied. The analysis involved lithological dismemberment of the productive Taskuduk suite as well as determination of sulfide mine-ralization zone boundaries. Findings. The research has shown that the productive levels reach down to 1500-m depth. The data interpretation has helped specify the geological structure and develop a model of ore-promising bodies of cupriferous sandstones at great depth. The applied complex data analysis has increased potential to prospect new loci of productive cupriferous sandstone deposits of Zhezkazgan type. Originality. The research has contributed significantly to understanding of the physical and geological factors influencing the copper ore distribution in deep layers. New physical and geological criteria, determining deep copper mineralization localization, have been identified which were not considered by earlier similar studies. Practical implications. The obtained new data as well as the developed methods are important while deep drilling planning and implementing to identify promising copper mineralization sites. The findings may be used to optimize exploration within the north-end of Zhezkazgan synclinal, and other districts having analogous geological conditions.

ПЕРВЫЕ СВЕДЕНИЯ О МЕДНОЙ МИНЕРАЛИЗАЦИИ РУДОПРОЯВЛЕНИЯ ШАРОМСКОЕ, ЦЕНТРАЛЬНАЯ КАМЧАТКА

The report provides new data on the mineralogy of the ores of the Sharomskoye copper ore occurrence, the Kirganik-Sharom ore zone in Central Kamchatka. Copper ores are confined to the central part of the submeridional massif of subalkaline metasomatites. Mineralization is disseminated, less often vein-disseminated in nature.The studied ore samples, collected during field works in 2023, are represented by silicified metasomatites with developed sulfide mineralization. Among the vein and accessory minerals are quartz, chlorite, barite and apatite. Ore minerals are represented by magnetite, chalcopyrite and bornite. Hematite and malachite are the most common supergene minerals, while cuprite and hydroxides of Fe and Cu are less common. The established chalcopyrite-bornite mineral association of the Sharomskoye ore occurrence is considered typical of other copper mineral prospects in central Kamchatka and is characteristic of porphyry copper deposits.

The structural elements controlling the subsurface mineralization as deduced from the integration of magnetic and self-potential methods, Wadi Khosh El-Daba area, southern Sinai, Egypt

Significant copper mineralization are observed to be associated, in most cases, with some radioactive anomalies related to increased uranium and thorium contents in Southern Sinai, Egypt. These mineralizations are related to intense post-magmatic, structurally controlled hydrothermal activities in many localities. Wadi Khosh El-Daba area is one of these locations which is mainly composed of monzogranites dissected by andesite dyke and pegmatite vein. This work deals with the application of ground magnetic and self-potential methods to establish the magnetic sources governing the mineralization, to interpret the significant trends that affected the study area, and to delineate the mineralized zones. The magnetic data were processed, enhanced and interpreted using advanced techniques, such as the first-order vertical derivative (FVD), the tilt derivative (TD), Euler deconvolution (ED), and source parameter image (SPI). The main structural lineaments/contacts that control the distribution of hydrothermal alterations and mineral distributions are oriented to the NW–SE, NE–SW, and NNW–SSE directions. The self-potential (SP) data show that there are numerous mineralized zones; most of them are distributed mainly along the structural lineaments deduced from the magnetic study. The quantitative interpretation revealed that the mineralized bodies are at shallow depths ranging from 5.6 m to 12.7 m, with half-width from 5 m to 13 m. These bodies are shallow to moderate dipping towards the south and north directions. Based on this study an anomaly map is originated to locate the preferred structural elements that may be controlling the mineralization in the area for further future exploration.