Search Results (338)

The aim of this study was to improve the efficiency of in situ uranium leaching by developing a specialized methodology for selecting rational parameters for the chemical treatment of production wells. This approach was designed to enhance the filtration properties of ores and extend the uninterrupted operation period of wells, considering the clay content of the productive horizon, the geological characteristics of the ore-bearing layer, and the composition of precipitation-forming materials. The mineralogical characteristics of ore and precipitate samples formed during the in situ leaching of uranium under various mining and geological conditions at a uranium deposit in the Syrdarya depression were identified using an X-ray diffraction analysis. It was established that ores of the Santonian stage are relatively homogeneous and consist mainly of quartz. During well operation, the precipitates formed are predominantly gypsum, which has little impact on the filtration properties of the ore. Ores of the Maastrichtian stage are less homogeneous and mainly composed of quartz and smectite, with minor amounts of potassium feldspar and kaolinite. The leaching of these ores results in the formation of gypsum with quartz impurities, which gradually reduces the filtration properties of the ore. Ores of the Campanian stage are heterogeneous, consisting mainly of quartz with varying proportions of clay minerals and gypsum. The leaching of these ores generates a variety of precipitates that significantly reduce the filtration properties of the productive horizon. Effective compositions and concentrations of decolmatant (clog removal) solutions were selected under laboratory conditions using a specially developed methodology and a TESCAN MIRA scanning electron microscope. Based on a scanning electron microscope analysis of the samples, the effectiveness of a decolmatizing solution based on hydrochloric and hydrofluoric acids (taking into account the concentration of the acids in the solution) was established for the destruction of precipitate formation during the in situ leaching of uranium. Geological blocks were ranked by their clay content to select rational parameters of decolmatant solutions for the efficient enhancement of ore filtration properties and the prevention of precipitation formation. Pilot-scale testing of the selected decolmatant parameters under various mining and geological conditions allowed the optimal chemical treatment parameters to be determined based on the clay content and the composition of precipitates in the productive horizon. An analysis of pilot well trials using the new approach showed an increase in the uninterrupted operational period of wells by 30%–40% under average mineral acid concentrations and by 25%–45% under maximum concentrations with surfactant additives in complex geological settings. As a result, an effective methodology for ranking geological blocks based on their ore clay content and precipitate composition was developed to determine the rational parameters of decolmatant solutions, enabling a maximized filtration performance and an extended well service life. This makes it possible to reduce the operating costs of extraction, control the geotechnological parameters of uranium well mining, and improve the efficiency of the in situ leaching of uranium under complex mining and geological conditions. Additionally, the approach increases the environmental and operational safety during uranium ore leaching intensification. Full article

The Mirim–Patos–Mangueira coastal lagoon system provides a wide range of ecosystem services. However, its vast territorial extent and the political boundaries that divide it hinder integrated assessments, especially during extreme hydrological events. This study is divided into two parts. First, we assessed the spatial and temporal patterns of water quality in the lagoon system using Sentinel-3/OLCI satellite imagery. Atmospheric correction was performed using ACOLITE, followed by spectral grouping and classification into optical water types (OWTs) using the Sentinel Applications Platform (SNAP). To explore the behavior of water quality parameters across OWTs, Chlorophyll-a and turbidity were estimated using semi-empirical algorithms specifically designed for complex inland and coastal waters. Results showed a gradual increase in mean turbidity from OWT 2 to OWT 6 and a rise in chlorophyll-a from OWT 2 to OWT 4, with a decline at OWT 6. These OWTs correspond, in general terms, to distinct water masses: OWT 2 to clearer waters, OWT 3 and 4 to intermediate/mixed conditions, and OWT 6 to turbid environments. In the second part, we analyzed the response of the Patos Lagoon to flooding in Rio Grande do Sul during an extreme weather event in May 2024. Satellite-derived turbidity estimates were compared with in situ measurements, revealing a systematic underestimation, with a negative bias of 2.6%, a mean relative error of 78%, and a correlation coefficient of 0.85. The findings highlight the utility of OWT classification for tracking changes in water quality and support the use of remote sensing tools to improve environmental monitoring in data-scarce regions, particularly under extreme hydrometeorological conditions. Full article

The objective of this paper is to evaluate the capability of various steel rope manufacturers to maintain the desired variability within the strength class of wires used in the production of steel ropes. From a service life perspective, it is optimal to achieve the narrowest possible strength class interval for wires integrated into steel ropes. However, the applicable EN 12385 standards permit a relatively wide interval of allowable strength class dispersion. The analysis encompasses 112 steel ropes tested over the period from 2000 to 2025. For the purpose of evaluating rope quality in terms of wire strength variability, the ropes were categorized into four quality classes. The assessment of wire strength was conducted using statistical quality control methods, specifically through the application of control charts. Based on these methods, the stability and capability of wire strength within each rope were verified. The results highlight the differences in wire strength performance across the evaluated quality classes. Full article

The worldwide expansion of geotourism and its ongoing development have captured the interest of numerous scholars, prompting them to investigate various theoretical dimensions within this emerging field. This paper explores the concept of geotourism products and the importance of comprehensively understanding this topic. A thorough review of the existing literature indicates that different researchers offer diverse definitions and interpretations of geotourism products. However, analysis of relevant publications reveals that these perspectives do not adequately incorporate the fundamental principles of geotourism alongside the well-defined and broadly accepted concept of tourism products in general. To facilitate the accurate analysis of research outcomes and to support the effective advancement of geotourism, this paper advocates for a clear and well-defined understanding of what constitutes a geotourism product. Full article

This study demonstrated the successful recovery of zinc, lead, and copper collective concentrates from historical metal-bearing mine tailings (sulfide–polymetallic ore with a composition of 7.38% Zn, 1.45% Pb, and 0.49% Cu) using froth flotation techniques, which were originally developed during uranium ore mining. Froth flotation techniques were used to justify suitability for recovering metals. The effects of a dosage of the foaming agent Polyethylene glycol (PEG 600) at 50 and 100 g t⁻¹, collector types Aerophine 3418A (AERO), Danafloat 067 (DF), and potassium ethyl xanthate (KEX) at 50 and 80 g t⁻¹, and a suspension density of 300 and 500 g L⁻¹ on froth flotation collective concentrates were investigated. The final collective concentrate achieved recoveries exceeding 91% for lead (Pb), 88% for copper (Cu), and 87% for zinc (Zn). The obtained concentrates were analyzed using Atomic Absorption Spectroscopy (AAS) and X-ray Fluorescence Spectrometry (XRF), while selected samples were further examined via Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS). The resulting sulfide concentrates can subsequently be treated using suitable hydrometallurgical techniques. The application of these concentrates in metal production would help reduce the environmental burden of mining activities. Full article

The mining industry faces increasing pressure to improve efficiency, reduce operational costs, and adapt to modern technological trends. Central to these challenges is digitalization. This paper compares the level of digitalization in the mining industry internationally and in Slovakia, raising the question of the feasibility of implementing digitalization tools in small-scale Slovak mining operations. The presented case study demonstrates the creation of a simulation model and 3D animation for the development of small and medium-sized open pit mines, using Tecnomatix Plant Simulation software version 2302.0004, empirical data collection, and programming with SimTalk 2.0. Internationally, digitalization through modeling and simulation is already at a much higher level, with advanced solutions such as digital twins. In contrast, digitalization in Slovak mining operations is limited to basic simulation approaches, with only a few documented attempts, highlighting substantial opportunities for further development. The simulation model developed in this study enables more efficient planning and management of logistics and transportation processes, with potential benefits for operational improvements, safety, and sustainability. Adopting digitalization, even in small-scale operations, can drive the future development of the Slovak mining industry. Full article

This study examines the formation of the clay mineral simonkolleite (Skl) in bentonites contaminated with zinc(II) chloride (ZnCl₂), a process that has been little documented in heterogeneous systems such as contaminated bentonites. We explain the contamination mechanisms and provide new insights into the mineralogical, structural, and physicochemical transformations occurring within these materials. The objective, explored for the first time, was to assess how the ZnCl₂-induced mineral phase formation influences the properties of bentonites used as sealing materials, particularly regarding changes in specific surface area and porosity. Three bentonites were analyzed: Ca-bentonite from Texas (STx-1b), Na-bentonite from Wyoming (SWy-3), and Ca-bentonite from Jelsovy Potok, Slovakia (BSvk). Treatment with ZnCl₂ solution led to ion exchange and the formation of up to ~30% simonkolleite, accompanied by a concurrent decrease in montmorillonite content by 9–30%. A suite of analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray fluorescence (XRF), and energy-dispersive X-ray spectroscopy (EDS), was employed to characterize these transformations. The contamination mechanism of ZnCl₂ involves an ion exchange of Zn²⁺ within the montmorillonite structure, the partial degradation of specific montmorillonite phases, and the formation of a secondary phase, simonkolleite. These transformations caused a ~50% decrease in specific surface area and porosity as measured by the Brunauer–Emmett–Teller (BET) nitrogen adsorption and Barrett–Joyner–Halenda (BJH) methods. The findings raise concerns regarding the long-term performance of bentonite-based barriers. Further research should evaluate hydraulic conductivity, mechanical strength, and the design of modified bentonite materials with improved resistance to Zn-induced alterations. Full article

Contemporary metropolises, particularly those in the Global South, grapple with the complex challenge of balancing urban development with environmental conservation. In such contexts, forest remnants often face constant threats from illegal urban encroachment and insufficiently defined boundaries, which undermine conservation efforts and hinder effective legal enforcement. This study explores cost-efficient, geographic-information-technology-driven solutions to improve the management of conservation units and incorporate them into cities’ multipurpose land cadastres. By employing tools such as a remotely piloted aircraft, total stations, and GNSS receivers, this work highlights the pivotal role of geotechnologies in safeguarding the urban natural heritage. These technologies not only address the pressures of urban expansion but also enable continuous monitoring and impact assessment through geographical information systems (GISs). To illustrate these applications, this study examines a case study from Rio de Janeiro, Brazil, the Darke de Mattos Municipal Park, to demonstrate how accurate geographic data can significantly enhance planning and management efforts while maintaining cost-effectiveness. Full article

Forage scarcity, intensified by climate variability and edaphoclimatic limitations in the Brazilian semiarid region, challenges regional livestock production. In this context, forage palm is a strategic alternative due to its drought resistance and environmental adaptability. However, little is known about the spatial and temporal dynamics of its cultivation. This study aimed to characterize the spatio-temporal dynamics of forage palm cultivation in Capoeiras-PE between 2019 and 2022 using remote sensing data and multitemporal analysis of the Normalized Difference Vegetation Index (NDVI), processed via Google Earth Engine. Experimental areas with Opuntia stricta (“Mexican Elephant Ear”) and Nopalea cochenillifera (“Miúda”) were monitored, with field validation and descriptive statistical analysis. NDVI values ranged from −0.27 to 0.93, influenced by rainfall, cultivar morphology, and seasonal conditions. The “Miúda” cultivar showed a lower coefficient of variation (CV%), indicating greater spectral stability, while “Orelha de Elefante Mexicana” was more sensitive to climate and management, showing a higher CV%. Land use and land cover (LULC) analysis indicated increased sparse vegetation and exposed soil, suggesting intensified anthropogenic activity in the Caatinga biome. Reclassified NDVI enabled spatial estimation of forage palm, despite sensor resolution and spectral similarity with other vegetation. The integrated use of satellite data, field validation, and geoprocessing tools proved effective for agricultural monitoring and territorial planning. Full article

For the European Union in the field of raw material policy, it is primarily important to ensure reliable, seamless, and unrestricted access to raw materials in all EU countries. An important aspect in assessing the European Union’s raw material policy is a detailed analysis of selected significant raw materials. This paper focuses on raw material policy within the European Union (EU). Specifically, it examines five types of raw materials: critical raw materials, metal ores, non-metallic minerals, fossil energy materials, and biomass. The research is oriented to analyzing the materials from the perspectives of consumption, mining, export, and import. The objective is to assess the European Union’s (EU) raw material policy by employing specific tools and statistical methodologies to analyze individual data. We aimed to assess the European Union (EU) raw material policy using selected statistical methods such as regression and correlation analysis, multivariate analysis, and pairwise correlation to reveal and describe the relationships between variables. Based on the examination of import and export data, it is evident that imports are on the rise while exports are declining. This trend underscores the EU’s continued reliance on raw materials sourced from other global regions. The results show that domestic production and consumption are sufficient; on the other hand, the EU remains dependent on imports of critical raw materials. The results are useful for the development of future EU raw material policy. Full article

The Coffea canephora market has grown significantly, driven by its economic relevance and improvements in beverage quality. Developing varieties adapted to local edaphoclimatic conditions is essential for supporting smallholder farmers, increasing productivity, and ensuring quality in the face of environmental challenges. This study evaluated 27 genotypes under two irrigation regimes using a split-plot design in a completely randomized block arrangement, with four replicates and three plants per plot. Growth and yield parameters were assessed. Genotypes 102, 103, 105, 106, 202, 209, 301, 303, and 305 showed significantly higher yields under full irrigation—up to 60% greater than under minimal irrigation—demonstrating strong responsiveness to water availability. In contrast, genotypes 203 and 206 performed better under minimal irrigation, with 29% higher yields, suggesting lower water requirements or greater drought tolerance. These findings highlight the potential for selecting genotypes suited to transitional altitudes that can benefit from targeted irrigation strategies. The combined use of irrigation and altitude-specific cultivation represents a viable and necessary approach to maximizing genetic potential, optimizing water use, and enhancing the sustainability of C. canephora cultivation in regions facing climate variability. Full article

The archaeological complex of the Benzú rock shelter and cave, located in Ceuta (Spain), represents a heritage site of significant scientific and historical value that is currently at risk due to natural processes and, in particular, the activity of a nearby quarry. This site has been occupied from the Palaeolithic to the Bronze Age and consequently has been the subject of systematic research since 2002, focusing on its stratigraphic sequence, lithic technology, exploitation of marine resources, and the connection between both shores of the Strait of Gibraltar. With the aim of preserving this endangered heritage, a methodology based on advanced digital technologies such as photogrammetry, 3D laser scanning, and GNSS georeferencing has been implemented. These tools have enabled the creation of high-precision, three-dimensional models of the rock shelter and the cave, which are useful for both documentation and monitoring of their structural condition. In addition, fracture networks have been identified, revealing a high degree of geotechnical vulnerability, exacerbated by blasting activities at the nearby quarry. The project has produced a digital twin of the site in an open access format, serving not only for preventive conservation but also for its enhancement through virtual tours, augmented reality, and accessible outreach activities. This digitalization has been essential to facilitate the access to heritage, particularly in areas that are physically difficult to access. Finally, the integration of these digital resources into institutional policies for the sustainable management of heritage is proposed, highlighting the importance of interdisciplinary approaches that combine archaeology, geotechnology, and scientific communication. The experience at Benzú is presented as a replicable model for the protection, interpretation, and dissemination of heritage sites located in fragile and threatened environments. Full article

The results of geotourism development in Slovakia do not correspond much to the idea of geotourism as a social priority, nor to the declared increased interest in all forms of responsible tourism. The development of geotourism, in the strict sense of the word, is a political phenomenon; here, it exists outside the legal framework. This paper examines the question of whether, to what extent, and in what manner the promotion of leading principles (such as the idea of sustainability and its manifestation in various forms of regulated tourism) should be enshrined in positive law, and what specific benefits this might bring for the development of geotourism in Slovakia. Given the questions posed are of a kind that jurisprudence may answer, the methods chosen are drawn from legal science, though also intersecting with several other social sciences. Accordingly, the approach is one of doctrinal interpretation, based on the scientific study of valid law. Slovak law as a whole, specifically as it relates to the implementation of sustainable development and regulated forms of tourism, thus sets the outer limits of the application of these interpretative methods (including linguistic, historical, and logical interpretation of law, among others). The article answers the question in the affirmative way and outlines prospects for positive change should current approaches be changed. Full article

In terms of climate change, while tourism’s natural resources may be considered climate vulnerable, a large part of tourism’s primary industries are high carbon consumers. With the growth of worldwide efforts to adopt climate resilience actions across all industries, Destination Management Organizations could become focal points for raising awareness and leadership among local tourism stakeholders. The manuscript communicates a simple, reproducible approach to observing and analyzing climate change at a high territorial granularity to empower local destinations with the capability to disseminate quantifiable information about past, current, and future climate projections. In relation to Slovakia’s 39 local destinations, the approach utilizes six sub-sets of the latest high-resolution Köppen–Geiger climate classification grid data. The main climate categories’ similarity for local destinations was measured across six periods through the Pearson Correlation Coefficient of Pairwise Euclidean Distances between the linkage matrices of hierarchical clusters adopting Ward’s Linkage Method. The Shannon Entropy Analysis was adopted for the quantification of the homogeneity of the DMOs’ main climate categories, and Weighted Variance Analysis was adopted to identify the main climate categories’ weight fluctuations. The current results indicate not only a major shift from destination climates classified as cold to temperate, but also a transformation to more heterogeneous climates in the future. Full article

Yield maps represent crop production output and are essential for evaluating within-field spatial variability. Managing this yield variability is critical for precision and digital agriculture to facilitate optimized crop yield and reduced environmental impact. This work evaluated the spatial and temporal variability in corn and soybean yield data from three conventionally managed agricultural fields, with nine, three, and four seasons’ data. The data variability was measured through standard deviation (SD) and coefficient of variation (CV%). After separately normalizing each year of the yield data set, the temporal variability (TSD and TCV%) was calculated by grid cell for each field across years. A new index is proposed in this paper, the yield performance index (YPI, the ratio of mean normalized yield (${\overline{Y}}_N$) to the TSD), as an index with a lower value for lower yield and higher temporal variability. Two, three, and four zones were delineated using only YPI. These zones were valuable for identifying areas needing particular attention, with consistently (i) high yields and low variability or (ii) low yields and high variability. Full article