The Cheshmeh-Hadi copper deposit is part of an Eocene volcano-sedimentary sequence located in the southern Sabzevar Zone. The lithostratigraphic sequence, from oldest to youngest, comprises basalt, basaltic andesite, andesite and pyroxene andesite, conglomerate, limestone, siltstone, gypsiferous marl, and Pliocene conglomerate. The mineralized one occurs within the conglomerate and at the contact between the conglomerate and andesite. The ore minerals consist of malachite-azurite, chalcocite, bornite, covellite and occasionally native copper. The associated hydrothermal fluids show moderate to high salinities, ranging from 3.09 to 13.39 wt.% NaCl equivalent, with homogenization temperatures between 89 and 387°C, indicating fluid mixing during ore formation. Chalcocite is rarely accompanied by quartz, suggesting low silica content in the ore-forming fluids. The δ³⁴S values of sulfide samples from the study deposit range from −24.1‰ to −2.6‰, while δ³⁴S values of hydrothermal H₂S range from −24.3‰ to −2.6‰. The δ¹⁸O values of hydrothermal fluids associated with mineralization fall within the range of basaltic rocks, meteoric waters, and sedimentary rocks. Geochemical variations in major and trace elements suggest the involvement of continental crustal contamination in the magmatic evolution. The studied volcanic rocks fall within the calc alkaline to shoshonitic fields, formed in a continental arc setting, and are derived from an enriched mantle source influenced by subduction-related fluids. These rocks are characterized by HREE depletion, moderate LREE enrichment, and a weak negative Eu anomaly. Based on the results, the Cheshmeh-Hadi deposit is classified as a stratabound copper sulfide deposit, formed in a volcano-sedimentary setting associated with a subduction-related magmatic arc environment.
This study investigates natural radioactive mineralization (uranium–thorium) in Mamuju, West Sulawesi, particularly within the fault-controlled Adang Volcanics, an area known for anomalous natural radiation. The objective was to evaluate vegetation stress as a proxy for radioactive mineralization by integrating satellite data and field validation. We processed Sentinel-2A data using band ratios (4/2 iron oxide, 4/3 ferric iron, 11/12 clay) and false colour composites to delineate alteration zones. The Red Edge Vegetation Index (REVI; B3, B4, B6) was calculated to detect vegetation stress. Fieldwork in December 2023 collected 68 SPAD chlorophyll measurements from ferns, interpolated with inverse distance weighting, and compared with independent radiation dose rates. The results show a strong correlation between REVI and SPAD (R² = 0.76), confirming the sensitivity of red-edge bands to chlorophyll variability. SPAD values decreased significantly in high-radiation zones, showing a strong negative correlation with dose rate (R² = 0.90). Values of 4–40 were typical in anomalous radiation areas, while >40 characterized lower exposure. Vegetation stress anomalies and satellite-derived Chlorophyll Index overlapped spatially with alteration zones and were concentrated in the Adang Volcanics along structural controls. Species differences among ferns indicated varied sensitivity to radiation. This integrated approach demonstrates the effectiveness of Sentinel-2 alteration composites, REVI, and SPAD validation as a rapid, lowcost framework for early exploration of radioactive minerals while also contributing to environmental radiation hazard assessment.
We present a hypocenter relocation analysis to examine the distribution of seismicity in the Central Java and Yogyakarta regions in Indonesia. The data were obtained from the BMKG earthquake database for the period August–October 2024, covering the area between 6.0˚–11.0˚ S and 108.5˚–111.6˚ E. The dataset was divided into three monthly groups to observe the spatial and temporal patterns of earthquake sources in the study area. The analysis was carried out by overlaying the relocated hypocenters onto active fault maps and the subduction pattern of southern Java, allowing for a clearer characterization of the earthquake sources. Data from August - October 2024, comprising 393, 424, and 276 earthquake events respectively, were analyzed using the Double - Difference relocation method based on 26,610 - 19,429 P-wave pairs and 21,447 - 15,933 S-wave pairs recorded by 28 seismic stations. The findings reveal significant activity along the Baribis - Kendeng Fault, Kebumen - Meratus Trend, and Progo - Muria Lineament, exhibiting diverse fault mechanisms and hypocenter depths from shallow to intermediate. Clustering near the Opak Fault Zone and associated structures indicates complex fault interactions with potential intersegment stress transfer, while offshore seismicity shows a steeply dipping subduction slab with intermediate- to deep-focus events (50-250 km). The combined occurrence of shallow crustal, intermediate, and deep intraslab earthquakes expands the regional hazard spectrum, highlighting risks of strong ground shaking, site amplification, and localized tsunamis. The findings highlight the importance of integrating multisource and multimechanism earthquake characteristics into probabilistic hazard models to improve spatial planning, infrastructure resilience, and community preparedness.
The Nawagai ophiolitic melange is present in the western part of the Main Mantle Thrust /Indus Suture Zone (MMT/ISZ) in northern Pakistan and is considered as a part of the fold belt that contains ophiolitic sequences. The studied manganese ore bodies are present in the Nawagai ophiolitic melange in the Mohmand District of Khyber Pakhtunkhwa, Pakistan. These ores are dislocated lenticular bodies of various size and are generally associated with the cryptocrystalline meta-chert. Both Mn-ores and the host meta-cherts are highly tectonized and are, therefore, subjected to metamorphism/ deformation. Mineralogically, the studied Mn-ores are dominantly composed of braunite with a lesser amount of pyrolusite and piemontite as Mn bearing phases while the gangue minerals are mainly cryptocrystalline quartz with a lesser amount of calcite. The Mn-phases are interlocked within the cryptocrystalline quartz; however, the cross cutting micro-veins of quartz and calcite are also noticed. At places the pyrolusite and piemontite are replacing braunite. Geochemically, the studied Mn-ores are highly variable in their grade. These are generally high-grade to low-grade but as a whole, from an economic perspective, these ores can be considered as low-grade ores on the basis of MnO, Fe2O3 and SiO2 contents. No correlation among the major elements has been found, however, significant positive correlation between SiO2 and MnO has been noted. The fractionation behaviour of Mn and Fe and the concentration of various major and trace elements suggest that the studied Mohmand area Mn-ores have been formed from the hydrothermal fluid distal to the source (vent) with the input from the pelagic sediments along the mid-ocean ridges within the Neo Tethys-Ocean. These have been obducted, as exotic bodies within ophiolitic sequences, on the Indian Plate due to the subduction of Indian Plate underneath the Kohistan Island Arc along the MMT/ISZ. These Mn-ores and the meta-cherts have attained severe metamorphism and deformation during and after the emplacement of the ophiolitic bodies in the existing position.
The Melawi region in Indonesia has been identified as a metamorphic-hosted uranium deposit. The occurrence of sedimentary formations in the downstream area suggests the potential for sandstone-type uranium deposits. Previous studies have concentrated on metamorphic-hosted mineralization, resulting in limited exploration of the sedimentary rocks. Geographic Information System (GIS) technology offers valuable support for mineral prospectivity analysis, including uranium exploration. Among various techniques, fuzzy logic has been demonstrated to be effective in generating prospectivity maps to guide uranium resource development. This research aims to develop a prospectivity map for a sandstone- type uranium deposit in the Melawi region. A GIS-based analysis is performed using available spatial datasets, including geological maps, digital elevation models, and uranium occurrences in Melawi. These datasets served as input for constructing a fuzzy logic model based on the genetic model of sandstone-type uranium deposits. The datasets were reclassified, assigned suitability scores, and operated within a fuzzy logic framework to generate a prospectivity map. The results indicate that 36.64% of the Melawi area is high prospectivity zones, 25.34% is medium prospectivity zones, and 38.02% is the low prospectivity zones. The northern part of Melawi exhibits the most favourability for sandstone-hosted uranium mineralization. This study demonstrates fuzzy logic as a practical tool to delineate the favourable area of a sandstone-type uranium deposit in Melawi. Nevertheless, incorporating more diverse spatial datasets and implementing systematic field validation is necessary to locate uranium deposits accurately.
Mining operations in underground coal mines, particularly those using the longwall method, require continuous progress and the avoidance of interruptions, as any stoppage can lead to roof collapse. Given the mechanization of coal mining and the underground extraction of this mineral, the use of powered supports is essential to prevent roof collapse. To maintain continuity in mining operations, increase production, and simultaneously control and reduce costs caused by downtime and failures of roof support systems, it is necessary to assess their reliability. This paper aims to analyze the reliability, maintainability, and availability (RAM) of powered support equipment. To achieve this, the hydraulic powered support system was selected for data collection and analysis. The results indicate that the time between failures (TBF) and time to repair (TTR) data of the subsystems followed a renewal process, except for the TBF data of the hydraulic subsystem, which followed a non-homogeneous Poisson process (NHPP). The reliability of the subsystems decreased to 85% after 25 hours. The maintainability analysis showed that most failures of the powered roof supports are repaired within 1 hour. Furthermore, the powered support systems operate under desirable conditions with 99.58% availability. However, in order to create an efficient and easy-to-manage maintenance schedule, it was suggested that preventive maintenance activities be performed at the end of each working day.
In the present study, we investigated the potential for enhancing the desorption of cobalt contamination in a sandy silty-clay soil contaminated with Cobalt(II)-chloride-hexahydrate. In soils containing silt–clay fractions, effective remediation is primarily prevented by strong surface binding and adsorption processes. Overcoming these limitations requires the establishment of favourable conditions for desorption. In contrast to industrial practices, the potential for desorption was investigated under gradually alkalinizing and reducing conditions. Based on the results, the decrease in the ORP of the saturated system, together with the increase in pH, initiated cobalt desorption. Consequently, within the range above a redox potential from 0 mV to -80 mV and above pH 7.8, the [Co(H₂O)₆]²⁺ cobalt-complex initially formed. Further alkalinization and decreasing redox potential led to the precipitation of the remaining contaminant as Co(OH)₂ cobalt hydroxide. As a result of treatment, an average of 7.33 mg of cobalt was desorbed from the silty-clay surface within 29 days from the initiation of the desorption treatment, corresponding to about 12% of the contaminant present in the system. Furthermore, a lognormal distribution-based prediction function series (average R² = 0.941) was fitted to the obtained concentration data. The results indicate, that the applied procedure is capable of desorbing approximately 15% of cobalt contaminant, which presumably indicates the desorption capacity of the system. The applied method is widely accessible, cost-effective, and environmentally friendly which qualities that are essential for industrial application. The proposed novel approach represents an efficient and effective complementary technique for the future remediation of certain heavy metal compounds.
The February 15, 1994 Mw 6.8 Liwa earthquake ruptured the southern Great Sumatran Fault (GSF), yet its static stress legacy and relation to subsequent seismicity remain weakly quantified. We integrate high-precision double-difference relocation with Coulomb failure stress (ΔCFS) modelling to evaluate post-1994 stress transfer along the Semangko sector. Using ~16,000 P/S picks and identical inversion settings, we test two 1-D velocity models; CRUST1.0 yields near-zero, narrow differential-time residuals (± 0.3–0.4 s) compared with broader heavy tails for AK135 (± 0.7–0.8 s) and are adopted for the final catalogue. Since phase archives are sparse before 2010, events from 1994 – 2009 are treated as background, whereas 2010–2024 earthquakes are relocated; quality control retains 416 events. Relocation suppresses the artificial ~10 km depth band and collapses epicenters into coherent clusters that delineate the West/East Semangko Faults and Semangko Bay. ΔCFS was computed for depths of 5–20 km and μ′ = 0.2–0.8. All scenarios produce the expected four-lobed right-lateral pattern with maxima >0.10 MPa around WSF-B, ESF-A, and the Kumering Fault. Relocated events preferentially occupy positively loaded regions: ~74% fall at ΔCFS > 0 and ~73% at ΔCFS ≥ 0.01 MPa (10 kPa), robust to μ′ and depth. The results indicate unresolved post-1994 loading on multiple Semangko branches and adjacent segments, highlighting the potential for cross segment triggering. We advocate expanding seismic and geodetic monitoring and targeted paleoseismic surveys in the Semangko–Kumering corridor to refine recurrence estimates and update physicsbased hazard models for southern Sumatra.
Coal-mining waste heaps represent a significant source of dissolved salts that can be mobilized by precipitation, posing risks to ecological safety and civil protection. This study focuses on the Chervonohrad Central Concentration Plant spoil heap in western Ukraine, where both thermally altered and unaltered argillite were tested. Laboratory column experiments were performed on 100 g samples flushed with deionised water to simulate leaching under controlled conditions. The cumulative leachate volumes reached approximately 432 L, allowing quantification of total dissolved solids and ionspecific contributions. We flushed 100 g columns for 24 h at 300 mL·min⁻¹ (8.5 L recirculated; ≈ 432 L passed), which yielded final filtrate total dissolved solids of 462 vs. 185 mg·L⁻¹ for burnt and unburnt argillite and cumulative leached masses of 3.93 vs. 1.57 g (≈ 2.5× higher for burnt). Early-time contrast was also strong: after 2 h (≈ 0.7 L), burnt reached 183 mg·L⁻¹ vs. 50 mg·L⁻¹ (≈3.7×). Physical observations were combined with a mathematical modelling approach to establish a precipitation-response relationship linking annual rainfall to total dissolved solids release. The results indicate a strong linear increase of annual salt release with precipitation, with burnt materials exhibiting markedly higher fluxes. This integrated framework demonstrates how laboratory data and simple models can be applied to anticipate pollutant releases, supporting ecological safety and informing civil protection measures in coal-mining regions prone to hydrological extremes.
CO₂ flooding has several advantages for enhancing oil recovery, including a reduction in crude oil viscosity, a decrease in interfacial tension, and an increase in oil volume through swelling. Although the mechanisms of oil swelling and extraction in CO₂–crude oil systems have been widely studied, the combined effects of temperature and oil composition on these mechanisms – and their influence on CO₂ displacement efficiency in porous media – remain insufficiently understood, especially under high reservoir temperatures. Therefore, this study investigates how temperature and crude oil composition affect swelling-extraction behaviour and CO₂ displacement efficiency. High-pressure and high-temperature (HPHT) PVT tests were conducted to evaluate swelling and extraction phenomena, while slim tube experiments were used to assess oil recovery performance. Tests were carried out at 70°C and 90°C using two light dead oils from an Indonesian field under varying injection pressures. Compositional analysis of produced oils was performed using Gas Chromatography (GC) and further interpreted through SARA fractions (saturates, aromatics, resins, and asphaltenes). Results show that lower temperatures enhance CO₂ extraction efficiency due to higher CO₂ density, leading to more pronounced swelling and miscibility effects. The miscibility was observed within the extraction region, emphasizing the role of hydrocarbon extraction in the miscibility mechanism. Higher temperatures were found to improve oil recovery, primarily due to viscosity reduction. Additionally, increasing CO₂ injection pressure reduced resin and asphaltene content, with evidence of asphaltene precipitation in the porous medium – particularly at lower temperatures. These findings provide valuable insight into how temperature and oil composition influence CO₂–oil interactions and support more effective implementation of CO₂ flooding at elevated reservoir temperatures.
This study investigates the 2023 Murghob Earthquake in Tajikistan (Mw 6.9) using modelling and multi-track InSAR techniques to analyze the surface deformation and fault dynamics. The modelling approach using Pyrocko produced observation, model, and residual images, each revealing aspects of the fault geometry and rupture characteristics. Our study identified a dominant right-lateral strike-slip event, with a calculated fault strike of 128°, dip of 67°, and rake of 177°, differing slightly from previous studies. Furthermore, the modelling also suggested mixed-slip faulting, incorporating normal faulting components along the Sarez Karakul Fault system and the Sarez-Murghab Thrust system. These findings indicate a more complex rupture process than previously emphasised in other models. Multi-track InSAR analysis supported these findings by providing high-resolution measurements of horizontal (dH) and vertical (dV) displacements. The horizontal displacements revealed significant strike slip movements (-0.53 to 0.12 meters) along the Aksu Murghab Fault system. Meanwhile, the vertical displacements indicated substantial uplift (-0.13 and 0.32 meters), likely due to normal and thrust faulting interactions. The results highlight the complexity of the region’s tectonic setting, which is influenced by multiple fault systems, including the Sarez-Karakul and Aksu Murghab faults. The study underscores the importance of integrating various geophysical methods to understand earthquake mechanisms better and improve seismic hazard assessments in tectonically active regions like Tajikistan.
Cave sediments are essential as they preserve valuable archives of past environmental and climate conditions that physical and chemical measurements can reveal. In this study, we explore the magnetic characteristics of the cave sediments collected from Solek Cave, West Sumatra, Indonesia to understand environmental processes within the cave. We employed rock magnetic methods, including magnetic susceptibility, isothermal remanent magnetization (IRM), anhysteretic remanent magnetization (ARM), and Curie temperature measurements. Additionally, we used X-ray diffraction (XRD) and scanning electron microscopy (SEM) in order to analyze the magnetic mineralogy and morphology of the cave sediments. The results show a high concentration of magnetic minerals, specifically ferrimagnetic groups, indicated by high magnetic susceptibility ranging between 210.7 and 1301.2 × 10-8 m3/kg, with a mean value of 602.7 × 10-8 m3/kg. The calculated χFD (%) values ranged from 0.2 to 6.6, mostly less than 2%, indicating coarse-grained, multidomain ferrimagnetic minerals. Moreover, results from IRM, ARM and XRD show that the magnetic minerals are dominated by coarsegrained magnetite with a grain size of around 20 to 110 μm. Curie temperature measurements also exhibit various titanium proportions, forming a titanomagnetite phase. The morphology and chemical compositions of the magnetic minerals, determined by SEM and energy-dispersive X-ray spectroscopy (EDS), also support the previous analyses, showing that titanomagnetite is the dominant phase, characterized by coarse grain size and angular shape. The uniformity of the magnetic characteristics and mineralogy suggests a titanomagnetite mineral source likely driven by lithogenic processes such as erosion and fluvial events.
The present study aims to compare the performance of data-driven and knowledge-driven Multi-Criteria Decision-Making (MCDM) in producing a mineral potential model in the Shahr e-Babak study area in south-eastern Iran. To achieve this goal, eight evidential layers, including geological, Cu signature, principal component analysis, argillaceous alteration, phyllic alteration, iron oxide alteration (Gossan), airborne geophysics layers, and linear structures, were preprocessed and produced. To produce the optimal model, first, all layers were scaled and shifted to the zero to one interval. To create the mineral potential model in the area, the Measurement Alternatives and Ranking according to Compromise Solution (MARCOS) method was introduced. For the exploration control layer weighting, two methods were used: the area prediction rate (P-A) method and the Analytic Hierarchy Process (AHP) method. Then, the results were compared with the Multi-Objective Optimization by Ratio Analysis (MOORA) method, which is a proven method in mineral potential assessment. To compare these methods, two methods – area prediction rate and the area under the curve (AUC) – were used. The findings show that the data-driven MARCOS approach provides the best performance and displays the best mineral potential model. The normalized density for the data-driven MARCOS, data-driven MOORA, knowledge-driven MARCOS, and knowledge-driven MOORA methods is equal to 3.00, 2.84, 2.7, and 2.57, respectively. The AUC for the data driven MARCOS, data-driven MOORA, knowledge-driven MARCOS, and knowledge-driven MOORA methods is equal to 0.939, 0.938, 0.933, and 0.932, respectively.
Selecting the optimal drilling fluid, defined by its weight and chemical type, is critical for preventing costly wellbore instability and catastrophic accidents. Traditional methods often rely on trial-and-error, past experience or simplified models that fail to capture the complex rock-fluid interactions. While data mining offers a promising alternative, a research gap exists in simultaneously predicting both mud weight and type. This study introduces a novel machine learning framework that concurrently predicts these essential properties. Utilizing a comprehensive dataset extracted from 50 years of daily drilling reports across 20 oil wells, we trained and compared three nature-inspired algorithms: Ant Colony (ACO), Bee Colony (BCO), and Emperor Penguins Colony (EPC) optimization. The results demonstrate that all models achieved high predictive accuracy, with the Bee Colony Optimization (BCO) algorithm emerging as the most precise, yielding a correlation coefficient (R²) of 0.9841 and a root-mean-square error (RMSE) of 0.0245. Furthermore, sensitivity analysis revealed that the Rate of Penetration (ROP) is the most influential parameter on mud properties, surpassing other drilling variables. A key practical finding was the consistent model consensus, with 79-87% confidence, that sea water-based mud with polymer and soltex additives (SW-PO-SX) is the optimal fluid for the studied field. This research provides a robust, data-driven solution that enables a systematic and proactive approach to drilling fluid selection, significantly enhancing operational safety and efficiency.
Undrained shear strength is considered as an essential factor to assess the stability of natural slopes and embankments. Traditionally, this parameter is determined through laboratory tests, which are often costly and time-consuming. Recently, geotechnical research has shifted toward using the Fall Cone Test (FCT) for short-term strength estimation. However, prior studies focusing on pure clay soils have often overlooked the combined impact of soil texture and stress conditions on the reliability of FCT-derived values. To address this gap, undrained shear tests were conducted using both the FCT and pocket vane shear devices on samples exhibiting various degrees of consolidation and different textures. The findings demonstrate that applying a constant cone factor of 0.8 in the FCT yields inconsistent results compared to vane shear tests, as this factor fails to reflect the soil’s consolidation state and the texture effect. To overcome this limitation, a new empirical expression for the cone factor, based on the overconsolidation ratio and fines content, is suggested. The results indicate that this approach significantly improves the accuracy of undrained resistance calculations by the FCT, thus providing a refined methodology for better risk management related to slope and embankments instability.
This article presents a comprehensive study on the management and optimization of frame-anchor support systems for seam preparatory excavations designed for the transportation of large-tonnage cargo via suspended monorail transport. With the intensification of underground mining operations and the increasing use of heavy mechanized transport, ensuring the stability and safety of mine workings under dynamic load conditions has become a critical challenge for engineering. The research proposes an innovative support technology based on the combined fastening of monorail systems to the crowns of metal arches and directly to the roof using deep-embedded anchors. This approach aims to reduce dynamic impacts on the excavation roof and improve the overall reliability of the support system. To evaluate the effectiveness of the proposed support design, a numerical modelling method was employed to simulate the interaction of components within the dynamic system “suspended monorail – support – rock mass.” The stress-strain behaviour of the frame-anchor structure under real load scenarios was analyzed using SolidWorks Simulation software. During the simulation, various parameters were systematically varied, including the spacing of support frames, the length and anchorage depth of the rock bolts, and the mechanical properties of the surrounding rock mass. The results of the analysis enabled the identification of rational design parameters that minimize deformation and enhance load-bearing capacity. In particular, optimal combinations of frame spacing and anchor configurations were found to significantly reduce stress concentrations and improve the stability of preparatory workings under dynamic loading from moving monorail trains. The study demonstrates that effective management of support system parameters can lead to improved safety, reduced material consumption, and faster development of mining panels. The findings have practical significance for the design of underground transport routes and can be incorporated into normative documents governing support systems in dynamically loaded mine environments.
Stope stability is a critical factor in underground mining, directly influencing safety, productivity, and overall mining efficiency. Traditional stope design methods often employ uniform stope lengths, disregarding geotechnical variability and thereby increasing the risk of instability or suboptimal dimensions. This study introduces an automated stability analysis approach that iteratively evaluates multiple stope dimension scenarios based on the Modified Stability Number (N’) to identify the optimum stable configuration. By conducting detailed stability assessments for each stope wall, the method provides a more accurate representation of geotechnical conditions compared to the conventional methods with uniform stope length. The case study demonstrates that this approach effectively reduces the total number of stopes while maintaining geotechnical stability, in contrast to conventional methods where 14%–40% of stopes exhibit instability. Furthermore, the optimization method achieves a balanced outcome between dilution control and operational efficiency resulted in lower stope production cost. The optimized configurations generated by the proposed method deliver the lowest total production cost, with estimated savings of approximately USD 1.6–2.4 million compared to conventional designs. These findings confirm that the optimization framework not only enhances geotechnical stability but also provides a demonstrable economic advantage, underscoring the importance of integrating geotechnical variability into stope design.
This study evaluates the effect of kaolinite addition on calcium carbonate water-based drilling fluids (WBM) through systematic laboratory testing. Kaolinite was incorporated at concentrations of 42.8 kg/m3 (15 lb/bbl), 85.6 kg/m3 (30 lb/ bbl), and 128.4 kg/m3 (45 lb/bbl) into a standard CaCO3-based WBM, and its influence on density, pH, filtration, rheology, and viscoelastic behavior was analyzed. The density of the base mud (10.15 g/cm3) increased to 11.00 g/c cm3 with 128.4 kg/m3 (45 lb/bbl) kaolinite, while pH rose proportionally with kaolinite content. Filtration tests at 93 degrees C (200 degrees F) and 2.07 MPa (300 psi) revealed that the base sample produced a filter cake thickness of 0.0098 in, which increased progressively with kaolinite addition. Rheological measurements showed Bingham plastic behaviour across all samples, with apparent viscosity increasing from 25 cP in the base mud to 33 cP at 128.4 kg/m3 (45 lb/bbl). Yield point and gel strength also exhibited consistent growth, indicating improved suspension capacity. Viscoelastic testing confirmed enhanced storage modulus (G') and gelling effect with higher kaolinite concentrations. These results demonstrate that kaolinite significantly enhances the density, filtration control, and rheological stability of CaCO3 WBMs, supporting its application as a cost-effective and multifunctional additive in drilling operations.
It is well known that in oil-producing countries with advanced industrial development, one of the most pressing unresolved challenges is protecting the internal surfaces of equipment and facilities from the effects of aggressive corrosive environments, thereby extending their operational life. Based on this, the present article explores the results of numerous laboratory tests on the effects of the newly developed organic MARZA-4 reagent and a composition provisionally named HAK-2 against hydrogen sulfide, carbon dioxide, and sulfate-reducing bacteria, which are primary causes of internal surface corrosion in the oil industry. For the first time, the MARZA-4 reagent was studied for its effectiveness against sulfate-reducing bacteria in aggressive corrosive environments such as neutral, acidic, and alkaline media, as well as in the “Postgate-B” nutrient medium. It was determined that the MARZA-4 reagent possesses bactericidal-inhibitor properties at an optimal concentration of 20 mg/L. At this concentration, its corrosion protective effect in neutral, acidic, and alkaline environments was found to be 98%, 98%, and 94%, respectively. In the “Postgate-B” nutrient medium, the bactericidal effect against Desulfovibrio desulfuricans and Desulfomicrobium cells was 78% and 81%, respectively.
This paper explores the optimization of in-situ uranium leaching efficiency through the application of oxygen as an oxidizing agent in the lixiviant. With this objective in mind, geological characteristics of the target site were examined, followed by a series of laboratory and pilot-scale experiments. The resulting data were systematically processed and analyzed. The influence of sulfuric acid concentration on the degree of oxygen enrichment in the lixiviant was established. Laboratory tests on core samples from the uranium deposit revealed consistent relationships between uranium concentration in the pregnant solution, the oxidation states of iron (Fe2+ and Fe3+) in lixiviant, and the level of oxygen saturation. Comparative results of uranium content in the pregnant solution over time were obtained for both the conventional and oxygen-enriched technologies. Laboratory results demonstrated a 23.0% increase in uranium concentration in the pregnant solution using an oxygen-enriched lixiviant over the control solution, indicating a potential reduction in recovery time and final metal production costs. Pilot-scale tests at a uranium mine confirmed the positive effect of oxygen-enriched lixiviant on iron oxidation and uranium concentration in the pregnant solution. All pumping wells within the test block showed increased or stabilized uranium concentration upon connecting a special injection system for oxidation in injection wells surrounding the pumping wells, and decreased uranium concentration after system disconnection.
