Mining

Pathfinding algorithms allow for the numerical determination of optimal paths of travel across many applications. These algorithms remain poorly defined for additional consideration of outside parameters, such as fluid flow, while considering contaminant transport problems. We have developed a pathfinding algorithm based on the A* search algorithm which considers the effect of fluid flow behaviors in two dimensions. This search algorithm returns the optimal path between two points in a setting containing impermeable boundaries, allowing for a computational approach to the determination of the most likely path of travel for contaminants or hazards of concern due to fluid flow. This modified A* search algorithm has applications in the statistical modeling of airborne contamination distributions, providing a relative estimate of the statistical relationship between two points in an underground mine’s ventilation system. This method provides a significant improvement to the spatial resolution of minimum-cost path methods currently in use in mine ventilation network software. Full article

The undercutting process is a technique employed to initiate the caving of the ore mass in block caving, achieved by creating a basal cut on the block scheduled to be submerged. The effective execution of the undercutting process involves numerous variables, such as the undercut height and the vertical section’s undercut geometry, whose influence has often been overlooked. This research presents a methodology for determining the undercut height in a post-undercutting scenario, including variables such as the undercut level design, the extraction level design, and the air gap. Integral to this methodology is a parameterization that estimates the undercut height, from which design abacuses can be created to aid the assessment of present and future operations for any block/panel caving operation that employs the post-undercutting variant. Additionally, two examples demonstrate the application of this methodology, revealing how alterations in the dimensions of the crown pillar and drawbells significantly influence the undercut height. The calculation methodology outlined in this document delivers an undercutting height, providing an evaluation methodology for ongoing operations. Consequently, any height exceeding this suggests a conservative approach, potentially offering an opportunity for design improvement and alignment with the described parameters. Full article

This article explores operational challenges in mining, with a focus on energy management amid depleting ore grades and rising costs. The urgent need for innovative energy management systems and strategies is highlighted by analyzing the unexplored landscape of mine energy budgeting and forecasting and identifying gaps in current practices. Drawing from the literature, this paper offers new insights into energy budgeting and the evaluation of energy efficiency initiatives by integrating traditional and advanced measurement and verification (M&V) techniques. M&V practices are crucial for energy management, particularly in deep-level mines, with a focus on practical knowledge and advanced methodologies. Key findings from this study show that integrating advanced M&V techniques with unplanned events is crucial to improve the financial management of mines. By leveraging these key findings, this article proposes a roadmap of the next seven milestones needed in advanced M&V research to aid effective energy management in a mining environment. If executed successfully, a practical method for applying advanced M&V processes to deep-level mining operations can be constructed. Such a generic method will enhance mining companies’ energy efficiency initiatives and improve financial management practices on a global scale. Full article

In recent decades, artisanal and small-scale gold mining (ASGM) has spurred population and economic growth in the small rural communities in which it is located, along with causing contamination of the soil, air, and water with grave effects on human health due to the uncontrolled use of mercury for gold processing activities. This study analyzes the levels of mercury in Secocha, an ASGM community in Arequipa, Peru. A total of 44 soil samples were taken from two ASGM commercial-extractive zones (n = 18) and non-processing urban zones (n = 26). Soil mercury analysis with atomic absorption spectrometry revealed average mercury levels of 86.11 mg/kg in commercial-extractive zone I, where ore processing has occurred for about 17 years, and mercury levels of 43.81 mg/kg in commercial-extractive zone II, where processing has occurred for about 7 years. In the urban zone, the average mercury level was 9.53 mg/kg. The average mercury concentrations for each zone exceed the relevant environmental quality standards established by the Peruvian Ministry of the Environment. In addition, urine samples were obtained from 15 miners and 15 people from the general urban population (non-miners). The average mercury level in the urine of miners was 7.04 µg/L, and in the urine of non-miners it was 0.49 µg/L. In both cases, the mercury urine level did not exceed the limits established by WHO and the Peruvian Ministry of Health, though miners’ elevated levels do raise concerns. Full article

The exploration of Pb-Zn mineralization in carbonate complexes during field campaign is a challenging process that consumes high expenses and time to discover high prospective zones for a detailed exploration stage. In this study, multi-sensor remote-sensing imagery from Landsat-8, Sentinel-2, and ASTER were utilized for Pb-Zn mineralization prospectivity mapping in the Akhlamad carbonate complex area, Razavi Khorasan, NE Iran. Due to the presence of carbonate formations and various evidence of Pb-Zn mineralization, this area was selected. Band composition, band ratio, principal component analysis (PCA), and SAM techniques for mapping alteration minerals as well as lineament analysis were implemented. Subsequently, a fuzzy logic model for identifying the prospective zones of Pb-Zn mineralization using multi-sensor remote-sensing satellite images was designed. The weight of each exploratory layer was determined using the fuzzy hierarchical method and the integration process of the information layers was performed using fuzzy operators. Finally, the existing mineral indications were used to evaluate and validate the obtained mineral potential map. The outcome of this investigation suggested several high-potential zones for Pb-Zn exploration in the study area. Full article

This paper review presents a comparison between conventional leaching and advanced photochemical leaching processes and their potential for use in chalcopyrite leaching. Likewise, it presents an analysis of the differences between the advanced leaching processes, photoleaching and radical-leaching, indicating that the photochemical mechanisms (photooxidation/photoreduction and generation of radical oxygen species (ROS) and radical sulfur species (RSS)) would improve the oxidative dissolution of chalcopyrite, taking advantage of the high oxidizing power of free radicals. Initial experimental results of solar-assisted radical-leaching on chalcopyrite are presented, demonstrating that sulfate radicals (SO₄⁻) allow copper to be leached at a rate 4.7 times higher than in the absence of radicals and sunlight. With these results, a radical-leaching process is presented for the first time, with a perspective toward the future development of a new hydrometallurgical route: solar-assisted radical-leaching. Full article

This paper details the design, development, and evaluation of VulcanH, a computerized maintenance management system (CMMS) specialized in preventive maintenance (PM) and predictive maintenance (PdM) management for underground mobile mining equipment. Further, it aims to expand knowledge on trust in automation (TiA) for PdM as well as contribute to the literature on explainability requirements of a PdM-capable artificial intelligence (AI). This study adopted an empirical approach through the execution of user tests with nine maintenance experts from five East-Canadian mines and implemented the User Experience Questionnaire Plus (UEQ+) and the Reliance Intentions Scale (RIS) to evaluate usability and TiA, respectively. It was found that the usability and efficiency of VulcanH were satisfactory for expert users and encouraged the gradual transition from PM to PdM practices. Quantitative and qualitative results documented participants’ willingness to rely on PdM predictions as long as suitable explanations are provided. Graphical explanations covering the full spectrum of the derived data were preferred. Due to the prototypical nature of VulcanH, certain relevant aspects of maintenance planning were not considered. Researchers are encouraged to include these notions in the evaluation of future CMMS proposals. This paper suggests a harmonious integration of both preventive and predictive maintenance practices in the mining industry. It may also guide future research in PdM to select an analytical algorithm capable of supplying adequate and causal justifications for informed decision making. This study fulfills an identified need to adopt a user-centered approach in the development of CMMSs in the mining industry. Hence, both researchers and industry stakeholders may benefit from the findings. Full article

This research applies remote sensing methodologies for the first time to comprehensively explore the geological and mineralogical characteristics of the Jbel Bou Dahar region. An integrated approach with multi-sensor satellite images, including ASTER, Landsat-8, and Sentinel-2 was applied with the aim to discriminate the different lithological units in the study area. We implemented a suite of well-established image processing techniques, including Band Ratios, Principal Component Analysis, and Spectral Angle Mapper, to successfully identify, classify, and map the spatial distribution of carbonate minerals, OH-bearing minerals, and iron oxide minerals. Due to its high spectral resolution in the short-wave infrared region (SWIR), the ASTER sensor provided the most accurate results for mapping carbonate and OH-bearing minerals compared to the Sentinel-2 and Landsat-8 sensors. Conversely, Sentinel-2 offers high spectral and spatial resolution in visible and near-infrared (VNIR) corresponding to the regions where iron oxide minerals exhibit their characteristic absorption peaks. The results confirm the advantages of remote sensing technologies in the geological and mineralogical exploration of the study area and the importance of selecting the appropriate sensors for specific mapping objectives. Full article

Arsenic and antimony are impurities that reduce the economic value of concentrates due to the environmental problems they cause. The removal of these impurities by hydrometallurgical means has been highly studied for sulfide copper concentrates using different leaching agents in an alkaline medium (NaClO, H₂O₂, NaOH, Na₂S, NaHS, and S). For a lead–silver concentrate consisting of galena, sphalerite, and pyrite, it was possible to selectively reduce the arsenic content from 1.10% to 0.55% and antimony from 2.41 to 1.04% through the digestion-leaching technique that uses elemental sulfur as a leaching agent in alkaline medium. The adequate powdered sulfur and sodium hydroxide dosage were 336 and 342 kg/t, respectively. The process was carried out at 120 °C with a liquid/solid ratio of 2 in digestion and 5.67 in leaching; the appropriate digestion and leaching time were 20 and 30 min, respectively. The thermodynamics and kinetics of this process turned out to be very complex due to the great variety of simultaneous leaching and precipitation reactions. The digestion process exhibited a mixed kinetic control, where diffusion through the boundary layer and the chemical reaction were the controlling steps with an activation energy of 11.05 kcal/mol. Full article

The mining industry is the leading supplier of raw materials in modern society. This sector of human activity has experienced a severe crisis due to the energy transition and has been revived in recent years due to the need for critical metals that are essential in the post-coal era. In underground and open pit mining, processes such as extraction, transportation, safety, underground ventilation, waste management, and rehabilitation are of major importance, and their “design” is critical to the economic survival of the mine. All the above processes required to operate a mine are strongly reminiscent of an example of nature’s workman: the ant. The sympatric insect uses the same processes as the ones aforementioned during the creation of its nest. The ants dig to “extract material from the ground”, and they transport this material from the nest‘s site to the waste deposition location. The ants ensure the safety of the underground opening and the proper ventilation needed for them to live there for a long time. This article attempts to identify the relations between all the above processes and sub-processes, and how human mining and ant colony development correlate with each other. Furthermore, we examine how an ant colony has aided in the development of mining technology, and what more humans can learn and adopt from a “miner” that is 66 million years old, in order to improve their processes. Full article

This article describes a part of the POTENTIALS project promoted by the Research Fund for Coal and Steel (RFCS) of the EU, which, in general, has aimed to develop business models for the reuse of former industrial and mining sites in different European regions. The goal of this project focused on the creation of so-called eco-industrial parks to enable sustainable energy production and reduce waste and pollution on coal sites in transition. A key aspect was the development of a suitable territorial impact assessment (TIA), a new and complex policy tool for the assessment of the territorial impacts of EU policies and projects on territorial cohesion. Therefore, the special TEQUILA (Territorial Efficiency, Quality and Identity Layer Assessment) approach is used to describe the TIA for this case and emphasizes its application in assessing ex ante the impacts of the transition from a coal site to an eco-industrial park. It underlines the need for a differentiated understanding of the regional characteristics and potential impacts of transition policies or projects. Furthermore, the process and results of applying the TEQUILA methodology, a multicriteria analysis, in the context of regionalized impact models has shown how important it is to select well-defined, expert-based criteria, but at the same time, to establish a system that is flexible and adaptable to the needs of political decision makers and stakeholders considering the normative weights of the criteria. This has been illustrated by some examples. Full article

Integrated geo- and environmental monitoring in mining represents a high-dimensional challenge (location, altitude/depth, time and sensors). This is challenging for experts but poses great problems for a multitude of participants and stakeholders in building up a complete process understanding. The Epe research cooperation aims to elucidate the ground movement at the Epe cavern storage facility with a public participation process. The research cooperation was founded by the city of Gronau, the citizens’ initiative cavern field Epe, the company EFTAS, Münster, and the Research Center of Post-Mining at the Technische Hochschule Georg Agricola, Bochum. This research cooperation is the first in Germany to involve direct collaboration between science and the public. In the cavern field, which has been in operation since the 1970s, brine is extracted, and at the same time natural gas, crude oil and helium, as well as hydrogen in the future, are stored in the subsurface. The technical focus of this work was the development of a high-resolution spatiotemporal analysis of ground movements. The area is monitored annually by the mining company’s mine surveyor. The complexity of the monitoring issue lies in the fact that the western part is a bog area and a former bog area. Furthermore, the soils in the eastern part are very humus-rich and show strong fluctuations in the groundwater and therefore complex hydraulic conditions. At the same time, there are few fixed scatterers or prominent points in the area that allow high-resolution spatiotemporal monitoring using simple radar interferometry methods. Therefore, the SBAS method (Small Baseline Subset), which is based on an aerial method, was used to analyze the radar interferometric datasets. Using an SBAS analysis, it was possible to evaluate a time series of 760 scenes over the period from 2015 to 2023. The results were integrated with the mine survey maps on the ground movement and other open geodata on the surface, the soil layers and the overburden. The results show complex forms of ground movement. The main influence is that of mining. Nevertheless, the influence of organic soils with drying out due to drought years and uplift in wet years is great. Thus, in dry years, ground subsidence accelerates, and in wet years, ground subsidence not only slows down but in some cases also causes uplift. This complexity of ground movements and the necessary understanding of the processes involved has been communicated to the interested public at several public information events as part of the research cooperation. In this way, an understanding of the mining process was built up, and transparency was created in the subsurface use, also as a part of the energy transition. In technical terms, the research cooperation also provides a workflow for developing the annual mine survey maps into an integrated geo- and environmental monitoring system with the development of a transparent participatory geomonitoring process to provide resilience management to a mining location. Full article

Direct and indirect effects after mine operations cease operating must ideally be subjected to perpetual monitoring routines in order to detect possible risks or avoid adverse effects on the surrounding ecosystems at an early stage. In this contribution, mining subsidence lakes created inside the nature reserve Kirchheller Heide and Hilsfeld Forest are subjected to analysis for a long-term monitoring scheme. For this purpose, we employ high-resolution unmanned aerial system (UAS)-based multispectral and thermal mapping tools to provide a fast, non-invasive and multitemporal environmental monitoring method. Specifically, we propose to monitor vegetation evolution through multispectral analysis, biotypes identification using machine learning algorithms, and water surface extent detection, together with their thermal behavior. The aim of this contribution is to present the proposed workflow and first results to establish a baseline for future analyses and subsequent surveys for long-term multi-temporal monitoring. Full article

This study investigated the application of machine learning to optimise the pumping load shift of a complex dewatering system in a deep-level mine, aiming to reduce energy costs associated with the dewatering process, which consumes an average of 14% of the mine’s electricity. Traditional practices, reliant on human control and simulations, often lead to inconsistent savings and occasional losses. The study employed multivariate linear regression (MLR) and extreme gradient boosting (XGBoost) on a mine dewatering system, to identify important parameters influencing the pumping load shift performance. Critical parameters significantly impacting the energy consumption of the dewatering system were identified by the best-performing model, XGBoost. Implementing a pumping schedule based on XGBoost insights resulted in consistent load shifting and enhanced energy cost savings. These findings highlight the potential of machine learning in comprehending and optimising complex systems in deep-level mines, with the case study approach proving effective in quantifying and validating real-world impacts. This approach could offer substantial energy savings through data-driven decision-making. Full article

In rock blasting for mining production, stress waves play a major role in rock fracturing, along with explosive gases. Better energy distribution improves fragmentation and safety, lowers production costs, increases productivity, and controls ore losses and dilution. Blast outcomes vary significantly depending on the choice of the explosive and the properties of the rock mass encountered. This study analyzes the effects of rock mass and explosive properties on blast outcomes via numerical simulation using data from the case study, and later validates the simulation results from the field blast fragmentation. The findings suggest that, for a given set of rock properties, the choice of explosive has a major influence on the resulting fragmentation. Strong explosives (high VOD and detonation pressure) favor large fracture extents in hard rocks, while weaker explosives offer a better distribution of explosive energy and fractures. The presence of rock structures such as rock contacts and joints influences the propagation of stress waves and fractures depending on the structures’ material properties, the intensity and orientations, and the direction and strength of the stress wave. When the stress wave encounters a contact depending on its direction, it is enhanced when traveling from soft to hard and attenuates in the opposite direction. The ability of the stress wave to cause fracturing on the opposite side of the contact depends on the intensity of the transmitted wave and the strength of the rock. Transmitted wave intensity is a function of the strength of the incident wave and the impedance difference between the interface materials. The presence of joints in the rock mass affects the propagation of the stress wave, mainly depending on the infill material properties and the angle at which the stress wave approaches the joint. Less compressible, higher stiffness joints transmit more energy. More energy is also transmitted in the areas where the stress wave hits the joint perpendicularly. Joints parallel to the free face offer additional fracturing on the opposite side of the joint. Other parameters, such as the joint width, continuity, fracture frequency, and the distance from the charge, enhance the effects. To achieve effective fragmentation, the blast design should mitigate the effect of variability in the rock mass via explosive selection and pattern design to ensure adequate energy distribution within the limits of geometric design. Full article

Extractive waste (EW), including tailings, is produced in large quantities during mining activities. In recent years, the linear economic model (“take-use-and-throw” approach) has been replaced by a circular approach, emphasizing the sustainable use and recovery of EW. The development of innovative protocols, such as Best Available Techniques (BATs), which aim at the technological and process improvement of more sustainable mining activities and at the production of renewable, highly performing green materials, has led to technological advancements, expertise in sustainability, and a reduced ecological footprint, potentially causing positive economic and social impacts and reducing environmental ones. Extractive waste and tailings, if suitably characterized, can be used to improve and make sustainable the works connected to the management of mining activities. The qualitative–quantitative characterization of EW is essential for subsequent reuse and for assessing the risk to human health and the extent of environmental impacts in the various matrices. The application areas vary according to the type of waste and mining tailings, the morphological characteristics of the deposits, and the geological, geomorphological, and logistic context of the area. Integrated protocols for sustainable EW exploitation and positive impacts on the economic, environmental, and technological/social level are analyzed. The present paper aims at providing an overview of challenges and potentialities connected to extractive waste (EW) management and potential exploitation to recover raw materials (RM), critical raw materials (CRM), and secondary raw materials (SRM). Full article

Uranium, a cornerstone for nuclear energy, facilitates a clean and efficient energy conversion. In the era of global clean energy initiatives, uranium resources have emerged as a vital component for achieving sustainability and clean power. To fulfill the escalating demand for clean energy, continual advancements in uranium mining technologies are imperative. Currently, established uranium mining methods encompass open-pit mining, underground mining, and in situ leaching (ISL). Notably, in situ leaching stands out due to its environmental friendliness, efficient extraction, and cost-effectiveness. Moreover, it unlocks the potential of extracting uranium from previously challenging low-grade sandstone-hosted deposits, presenting novel opportunities for uranium mining. This comprehensive review systematically classifies and analyzes various in situ leaching techniques, exploring their core principles, suitability, technological advancements, and practical implementations. Building on this foundation, it identifies the challenges faced by in situ leaching and proposes future improvement strategies. This study offers valuable insights into the sustainable advancement of in situ leaching technologies in uranium mining, propelling scientific research and practical applications in the field. Full article

Navigating miners during an evacuation using smart evacuation technology can significantly decrease the evacuation time of an underground mine in case of emergency hazards. This paper presents a mathematical programming model to calculate the most efficient escape path for miners as a critical component of smart evacuation technology. In this model, the total evacuation distance of the crew is minimized and scenarios with blocked pathways and stamina categories for the miners are simulated. The findings revealed that all the tested scenarios were technically feasible. Using the feature that filters out blocked pathways has no downsides as safer routes are calculated and there is no penalty in the computation time. This paper also discusses the social and technical issues that must be resolved before the algorithm can be implemented as an actual escape solution. Full article

The geotechnical characterization of the subsurface is a key requirement for most soil investigations, incl. those for reclaiming landfills and waste dumps associated with mining operations. New sensor technology, combined with intelligent analysis algorithms, allow for a faster and less expensive acquisition of the necessary information without loss of data quality. The use of advanced technologies to support and back up common site investigation techniques, such as cone penetration testing (CPT), can enhance the underground characterization process. This study aims to investigate the possibilities of image analysis for material recognition to advance the geotechnical characterization process. The grey level co-occurrence matrix (GLCM) image processing technique is used in a wide range of study fields to estimate textures, patterns and structure anomalies. This method was adjusted and applied to process the video recorded during a CPT sounding, in order to distinguish soil types by its changing surface characteristics. From the results of the video processing, it is evident that the GLCM technique can identify transitions in soil types that were captured in the video recording. This enables the prospect of image analysis not just for soil investigations, but also for monitoring of the conveyor belt in the mining field, to allow for efficient preliminary decision making, material documentation and quality control by providing information in a cost effective and efficient manner. Full article