Large-scale Mining Operations Research Articles

Compound criticality of bauxite production: implications for sustainability and trade neo-colonialism

We describe bauxite as having compound criticality. 1, it is a critical raw material (CRM) from which alumina and thereby aluminium are produced, and aluminium has the highest production levels of all metals deemed significant to the Clean Energy Transition. 2, gallium is a by-product CRM, extracted during alumina refining. 3, multiple other CRM by-products could be extracted during alumina refining: scandium, lithium, cobalt, titanium and REE. 4, production is profoundly influenced by price inelasticity (for by-products), regime instability of bauxite production and supply chain bottlenecks. We review the geology of bauxite ore deposits as a function of complex CRM supply potential, and interrogate the trait of criticality using four of the world's dominant producer nations of bauxite and potential patterns of value addition from raw materials to refined products. Trade agreements and mitigation strategies to ensure security of supply in consumer regions prioritise removal of low-cost bauxite by large-scale mining operations and shipping of unprocessed ore at high CO 2 footprint from producer nations. Ore-refining nations have investments that are deemed extractive because they remove large quantities of raw material for export with minimal or no in-country processing and they can also place producer nations in debt. Opposition to neo-colonial debt-trap policies and extractive practices increases regime instability and thereby criticality. We highlight how societal-environmental-political interactions and the mineral-energy nexus in the bauxite-aluminium supply chain are subject to increasing turbulence, which may reshape the geographies of supply chains. Thematic collection: This article is part of The energy-critical metals for a low carbon transition collection available at: https://www.lyellcollection.org/topic/collections/critical-metals

Research on Pressure Relief and Anti-impact Technology for Segmental Hydraulic Fracturing in Directional Long Borehole in Roof

After large-scale underground mining operations in coal mines, the stress of the overlying strata above the goaf is transferred to the surrounding support areas, creating support pressures. These pressures can easily trigger dynamic disasters such as gas outbursts and roof collapses, seriously threatening mine safety and production. To ensure the safety of underground mining operations, directional long borehole segment hydraulic fracturing technology was used in the roof strata of the 2305 comprehensive caving working face of Cuijiagou Coal Mine in Shaanxi Province to conduct experimental research on the technology of directional long borehole segment fracturing for pressure relief and anti-impact. The hydraulic fracturing of the roof’s directional long borehole reduced the stress peak coefficient of the coal body in front of the working face (K≈2.9), blocked the propagation of mining stress and high stress in the goaf to the mining roadway, reduced the deformation of the mining roadway, and reduced the average working resistance of the working face support by 22% compared to the working face without any measures. The effective reduction of the length of the hanging roof, the improvement of the support resistance, and timely roof collapse during the working face mining period helped ensure the initial pressure did not form a strong impact. The initial pressure interval of the thick hard roof calculated theoretically was shortened by 53%, and the periodic pressure interval during normal mining was reduced by 27% compared with the 2303 working face under the same geological conditions. The experimental results show that the coverage of the directional long hole on the roof is extensive, with the utilization rate of segmented hydraulic fracturing wells reaching up to 80%. This technology effectively diminishes the strength of the roof above the coal seam on a large scale, thereby reducing the periodic pressure interval and intensity. As a result, it prevents the impact caused by the hanging roof during the mining period of the working face, ensuring a safe working environment for underground workers and facilitating the safe and efficient progress of mining operations.

A remote sensing based index for assessing long-term ecological impact in arid mined land

Large-scale mining operations in western China would accelerate the fragility and degradation to arid ecological environments. Remotely sensed monitoring and assessing of mining effects in long term change could provide sound understanding to guide mine ecological restoration and local ecosystem sustainability. This study's primary goal is to develop an arid mined land status (AMLS) index based on remote sensing data to assess ecological effects in mining areas of arid land. Furthermore, the performance of AMLS was contrasted with that of the remote sensing ecological index (RSEI) and the land surface ecological status composition index (LSESCI) in arid mines under various landscapes conditions. Eventually, the Sen + Mann–Kendall method was used to analyze the temporal and spatial land status variations in the mining effect between 2005 and 2020 based on Landsat time-series images. The following was revealed by the results: (1) AMLS had high correlation (r > 0.65) with each factor, including bare soil flatness, dryness, land surface temperature, and slope. (2) Comparing with LSESCI and RSEI, the proposed AMLS could characterize the mining area and surrounding natural bare soil and rock with different ecological status levels in three mines, hence indicated the mining directional heterogeneity and distance attenuation of ecological status. (3) Based on time series Landsat data, the AMLS demonstrated long-term ecological variability from 2005 to 2020 due to mining and reclamation in three mines.

Rock fragmentation size distribution control in blasting: a case study of blasting mining in Changjiu Shenshan limestone mine

Deep-hole bench blasting is the primary method for aggregate extraction in mines. However, factors such as complex geological conditions and suboptimal blasting parameters often result in uneven rock fragmentation and high fines content. This not only increases the cost and energy consumption of subsequent aggregate processing but also has adverse environmental implications. In this study, based on the Changjiu Shenshan limestone aggregate mining project in China, large-scale blasting experiments were conducted to investigate the influence of rock properties and blasting parameters on the size distribution of post-blast fragments and fines content. The results of the blasting experiments indicate that by controlling the size of the crushing zone and adjusting explosive performance, it is possible to significantly reduce fines content while improving mining efficiency. Recommended values for drilling and blasting parameters have been proposed based on geological conditions to more effectively control the generation of fines. The results highlight the importance of optimizing blasting parameters and charge structure for large-scale mining operations to achieve uniform rock fragmentation and low fines content. By adopting explosive performance adjustment methods based on reasonable control of the crushing zone, improving explosive performance can improve the economic benefits of mining operations, reduce energy consumption, and contribute to environmental protection.

Assessing the environmental impact of gold production from double refractory ore in a large-scale facility

Despite the strict environmental management regulations, there is still a considerable adverse impact on the ecosystem and human health when it comes to large-scale gold mining operations. Gold mining is an energy-intensive process that can discharge substantial quantities of chemicals combined with gaseous emissions into the environment. Considering gold mining's significant role in Nevada's economy and the growing concern about climate change, it's necessary to investigate the environmental burdens of this sector. To provide a comprehensive environmental perspective on the large-scale gold mining operations in Nevada, this study used a life cycle assessment (LCA) approach to evaluate the environmental burdens of gold production from double refractory ores in the roasting process. The Tool for Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI) method was used to evaluate the categories of acidification, ozone depletion, global warming, smog, carcinogenics, non-carcinogenics, respiratory effects, and fossil fuel depletion. Results showed that major contributors to greenhouse gas (GHG) emissions were grinding and off-gas treatment stages being responsible for 34.80 % and 56.10 % of the total global warming, respectively. The carbon footprint for producing one kg of gold was 12,200 kg CO2-eq. Sensitivity analysis was also employed on electricity to observe the influence of electricity on key contributor stages. A 10 % change in electricity reduced the GHG emissions in crushing and grinding by 12.2 % and 7.10 %, respectively, while delivering an insignificant effect on the off-gas treatment. Significantly, this study stands as the first initiative to apply LCA in the North American mining industry, with a unique focus on the off-gas treatment post-roasting and its associated emissions. Our findings can serve as a foundational database, aiding stakeholders in making informed decisions and enhancing sustainable practices in the gold mining industry.

Microbial communities from weathered outcrops of a sulfide-rich ultramafic intrusion, and implications for mine waste management.

The Duluth Complex (DC) contains sulfide-rich magmatic intrusions that represent one of the largest known economic deposits of copper, nickel, and platinum group elements. Previous work showed that microbial communities associated with experimentally-weathered DC waste rock and tailings were dominated by uncultivated taxa and organisms not typically associated with mine waste. However, those experiments were designed for kinetic testing and do not necessarily represent the conditions expected for long-term environmental weathering. We used 16S rRNA gene methods to characterize the microbial communities present on the surfaces of naturally-weathered and historically disturbed outcrops of DC material. Rock surfaces were dominated by diverse uncultured Ktedonobacteria, Acetobacteria, and Actinobacteria, with abundant algae and other phototrophs. These communities were distinct from microbial assemblages from experimentally-weathered DC rocks, suggesting different energy and nutrient resources in environmental samples. Sulfide mineral incubations performed with and without algae showed that photosynthetic microorganisms could have an inhibitory effect on autotrophic populations, resulting in slightly lower sulfate release and differences in dominant microorganisms. The microbial assemblages from these weathered outcrops show how communities develop during weathering of sulfide-rich DC rocks and represent baseline data that could evaluate the effectiveness of future reclamation of waste produced by large-scale mining operations.

A new model for the economic impact assessment of large-scale and deep open-pit mines

ABSTRACT This study focuses on examining economic impacts associated with deep and large-scale open-pit mining operations, which are often neglected in environmental impact assessments. Using Z-Fuzzy Delphi AHP and scenario-based techniques, 28 economic impacts were classified into seven categories and evaluated for the Sungun Copper mine in northwest Iran. Results indicated that socioeconomic factors had the highest weight (21.4%), while monetary factors had the lowest weight (7.5%). The economic sustainability score for the SCM was calculated to be 2.111, indicating poor economic performance. This research highlights the importance of considering economic impacts in mining operations for sustainable development.

Numerical investigation of seismic wavefield characteristics induced by a tensile source in a heterogeneous mining environment

Mining-induced tremors serve as the main dynamic stress source of coal bursts which represent one type of the most critical mining disasters in underground coal mines. To evaluate coal burst risks and comprehend the response of the coal-rock mass to seismic waves, microseismic monitoring stands as the principal method. By inferring the zones with elevated coal burst risks based on the seismic event clusters, valuable insights can be gained. However, because of limited seismic monitoring results generated from an individual seismic event, the recognition of the corresponding dynamic disturbance process remains ambiguous. The dynamic disturbance process presents immense complexity due to the focal mechanism and heterogeneous medium, particularly under the effect of structural heterogeneity induced by large-scale mining operations. In this study, forward numerical modelling was employed to gain the comprehension of seismic wave propagation affected by extraction zones. The findings revealed heightened intricacy of the wavefields and increased displacement concentrations around the working face. The characteristics of peak particle velocity (PPV) and displacement spectra were investigated in the near- and far-field zones, respectively. Owing to the existence of the extraction zone, both a significant amplification effect and the redistribution of PPV were observed around the near-field zone. The intricate wavefield caused by the focal mechanism and extraction zones resulted in more scattered distributions of the low-frequency spectral level, which can potentially cause an overestimation of source intensity. However, the impact of the complex wavefield on the corner frequency was limited. Through the analysis of the PPV attenuation law, as well as the distribution of both seismic moment and source radius, this study offered valuable insights for seismic risk assessment. The forward modelling approach facilitated the identification of high-risk potential areas resulting from seismic events, which deepened our comprehension of the dynamic disturbance process in the complex underground mine environment.

The arc loss challenge: A novel industrial benchmark for process analytics and machine learning

Rapid development in data-driven process monitoring has provided a rich selection of models and data preprocessing strategies for applications such as fault detection and diagnosis. However, the development, comparison, and selection of process monitoring algorithms can become complicated and unnecessarily onerous. As a result, numerous publicly available benchmark datasets have emerged in the literature. Unfortunately, benchmark literature often suffers from problems such as low fidelity, inconsistent usage, and lack of transparency. This paper presents a benchmark challenge based on a large-scale industrial dataset that aims to enhance the evaluation and comparison of learning algorithms and overall data preprocessing workflows. We introduce the arc loss challenge, a machine learning benchmark with data from a large-scale mining and pyrometallurgy operation. By providing a supervised learning challenge based on large quantities of raw industrial process data with transparent and consistent evaluation procedures, the arc loss challenge is a unique contribution to fault detection benchmarking.

Environmental Noise Impact Assessment for Large-Scale Surface Mining Operations in Serbia

Noise emissions are a significant environmental impact caused by the mining industry in all technological phases of surface mining, mineral processing, and waste disposal. This paper presents the role of noise impact assessment and control in large-scale surface mining operations. Mine planning develops the model of mining operations, ore excavation, and waste dumping scheduling and processing rates, including spatial distribution of mining activities. Such a level of mine planning requires an environmental impact assessment study. This can be achieved by applying noise impact assessment models. The described approach can be used to verify the effectiveness of the proposed protection measures to reduce or eliminate the identified negative impacts. This paper presents a case study of environmental noise impact assessment and control at the Serbia Zijin Copper DOO Bor mine, encompassing the analysis of the noise protection measures efficiency within the planning of large-scale mining operations at the open-pit mine Veliki Krivelj.

Факторы изменения сейсмического режима и локализации опасных зон при крупномасштабном техногенном воздействии

Large-scale mining operations over 90 years at the Khibiny apatite-nepheline deposits that are characterized with the conspicuous gravity-tectonic type of the stress-strain state have transformed the initial stress field of the rock massif, which has led to the recurrent occurrence of rockbursts. This problem retains its relevance due to constant increasing intensity of mining operations at the apatite mines during the last two decades and complicated mining, geological and geomechanical conditions. Accordingly, the dynamic rock pressure is increasing. We have retrospectively analyzed data on the manifestations of geodynamic events in the Khibiny rockburst-hazardous deposits and determined a set of factors that influence the changes in seismic behavior and localization of hazardous zones in complicated mining and engineering systems. We have systematized the data of long-term observations on dynamic rock pressure manifestations at the Khibiny apatite mines, taking into account the seismicity parameters, the scale of mine damage, the mining-induced stress fields, and geological and geomechanical features of the rock massif at specific time points. A structural scheme has been developed and ranking of factors has been carried out, considering the time of impact on the rock massif.

Assessing the Environmental and Social Impact of Large Scale Mining Operations in India: An Empirical Investigation

Since the inception of human society, there have been mining activities, and since the Stone Age, minerals have aided in advancing human civilization. The mining sector directly influences the macro economy by enhancing infrastructure, providing employment, fostering rural community development, and opening up new derivatives and downstream industries. Numerous vast deposits of numerous essential minerals and their small- to large-scale mining help India's economy thrive. In the past, with little regard for the environment, the local people, or development mining operations were conducted primarily for the advantage of the mining industry. However, even beyond the actual limits of individual mining leases, the extraction of coal and other minerals has resulted in varied degrees of social footprints through the destruction of the environment, implications for human health, and social displacement. It is the operating miners' duty to make sure that all pertinent problems and effects are recognized from the outset. The primary areas of environmental and social implications include impacts on biodiversity and habitat, problems with waste management, indirect effects, poverty alleviation, and wealth distribution.

Mining for the Bomb: The Vulnerability of Buried Plutonium to Clandestine Recovery

Efforts by the United States and Russia to bilaterally reduce their weapons plutonium stockpiles are currently stalled following a U.S. decision to dilute and bury excess plutonium in a geologic repository. Russia has derided this approach as impermanent and easily reversible. Conversely, many analysts contend that the recovery of buried plutonium would require large-scale mining operations, rendering it observable and preventable. Here, we show that the use of advanced mining techniques overlooked in prior analysis (namely, salt solution mining and in situ leaching) would enable the rapid, clandestine recovery of buried plutonium. Burial would therefore yield a novel plutonium geologic resource. We attribute the persistence of international technical controversy over the permanence of plutonium burial to state-level divergence in U.S. and Russian technological framings of plutonium and geologic repositories—distinct socially constructed understandings of the meanings, uses, and risks of these technologies.

Introduction: Quo Vadis , Latin America? Human Rights, Environmental Governance and the Sustainable Development Goals

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Searching for New Political Spaces: Negotiating Citizenship and Transnational Identities on Mongolia’s Mining Frontier

With two of the world’s largest mining projects, Mongolia has become one of Asia’s key mineral producers in the past 20 years. Mongolian pastoralist communities living in the South Gobi region in the vicinity of large-scale mining operations have recently turned to transnational dispute resolution arenas to lodge their grievances and seek redress. Notably, these pastoralists have sought to trigger international grievance mechanisms on the basis of being indigenous people, even though they are not recognised as such by their government. This article situates this contemporary mobilisation of pastoralist communities in relation to large-scale mining projects within a longer history of state (de)regulation of the pastoralist economy. It reflects on the role of non-state legal norms and mechanisms in introducing new forms of legal and political subjectivity into the milieu of discourses surrounding Mongolian pastoralist identity and livelihoods. The article reflects on the potential implications of extractive economy upon transnational identity formation, local/national political spaces, and strategic negotiations with state and corporate power.

“They are almost humans like us”: indigenous politics and policy dismantling under Bolsonaro’s government

This paper argues that three ongoing dismantling processes target the Brazilian indigenist policy under Bolsonaro’s government: (1) the dismantling of the land claims recognition policy and institutions; (2) the dismantling of the protection of indigenous lives due to the increasing violence against indigenous peoples and the COVID-19 pandemic; and (3) the dismantling of the integrity of traditional territories related to government plans to open indigenous lands to large-scale agricultural and mining operations. On the other hand, we point out that Brazilian indigenous movements’ contemporary strategies are developing to fight back against the dismantling of indigenist policy. We use primary and secondary data to investigate those topics, discussing them in depth using the policy-dismantling theoretical framework. We conclude by pointing to the fact that the ongoing dismantling may contribute to the genocide of Brazilian indigenous peoples.

DEVELOPMENT OF INDUCED SEISMICITY IN MINING TASHTAGOL IRON ORE DEPOSIT: RETROSPECTIVE ANALYSIS AND FORECAST

Using the example of the Tashtagol iron ore deposit, an approach has been implemented that makes it possible to reveal the space-time relationships between the parameters of random and deterministic processes of various physical nature, which occur in the rock mass during large-scale mining operations. The approach consists in cross correlation analysis of long time series “number and energy of weak and moderate dynamic events” and “variation of stress field parameters” in different areas of geomechanical space of the object under study. According to the data of automated microseismic control system of the mine (from 1989 to 2019) and calculation results based on the developed 3D model of the deposit, the values of correlation coefficients r between number N of seismic events with an energy of up to 3 kJ and increments of the maximum tangential T and average S stresses in different blocks were determined. The regression dependences N(T) and N(S) constructed for statistically significant r were verified by comparing the predicted and real values of N in 2020. The obtained dependences can be used for geomechanical justification of reserves mining using forward calculations of the stress state and, on this basis, for assessing seismic activity level using the found correlation dependences.

Seabed mining could come at a high price for a unique fauna.

The deep seafloor is teeming with life, most of which remains poorly known to science. It also constitutes an important reserve of natural resources, particularly minerals, that mining companies will start harvesting in the next few years (Nat Rev Earth Environ, 1, 2020, 158). In this context, broad biodiversity assessments of deep-sea ecosystems are urgently needed to establish a baseline prior to mining. However, significant gaps in our taxonomic knowledge and the high cost of sampling in the deep sea limit the effectiveness of conventional morphology-based surveys. In this issue of Molecular Ecology, Laroche et al. (Mol Ecol, 2020) capitalize on high throughput molecular methods to conduct one of the most detailed and rigorous surveys of the composition and biogeography of deep-seafloor metazoan communities to date. The authors show that deep seamounts in the Clarion Clipperton Zone are inhabited by rich metazoan communities that are distinct from those of the surrounding abyssal plains. These results have important conservation implications: if communities on deep seamounts were to persist after large-scale industrial mining operations on the surrounding plains, the seamounts would not serve as appropriate reservoirs to repopulate impacted areas.

Predicting the Geomechanical Properties of Hard Rocks Using Analysis of the Acoustic and Vibration Signals During the Drilling Operation

Evaluating the physical and mechanical properties of materials such as rock or concrete is among the most significant issues in engineering studies. Measurement of the properties of the rocks either in the laboratory or in the field needs the standards and specific methods. Also, most of these tests need time and a large number of rock samples. Therefore, finding a method that can be accurately, quickly, and reliably predict the properties of rocks will provide a great advance in the quality of studies before or during the projects. The purpose of this paper is to find a method for predicting and determining the geomechanical properties of hard rocks during the drilling operation. For this purpose, after the preparation of the rock samples, acoustic and vibration signals propagated during the drilling process were recorded and processed. After analysing the acoustic and vibration signals, statistical analysis for investigation of the relationship between the properties of the rocks and the acoustic parameters was performed. Sound Pressure Level (SPL), First Dominant Frequency (FDF), and Vibration Level (VL) were selected as predictor variables for measuring and predicting Uniaxial Compressive Strength (UCS), Brazilian Tensile strength (BTS) and Schmidt rebound number (SRN) by multivariable regression. Results of statistical analysis show that there is an acceptable correlation coefficient between rock properties and properties of acoustic and vibration signals of the rock drilling operation. Hence, this method can be used as a relatively inexpensive, non-destructive, reliable and real-time method in large-scale mining or civil operation for predicting the rock properties.

Artisanal Gold mining in Las juntas de Abangares, Costa Rica: Approaches and barriers to achieving sustainability objectives

Gold has been mined in the area surrounding the small town of Las Juntas de Abangares in Northwestern Costa Rica for over 100 years. Originally through large-scale foreign-based industrial mining operations, now gold is exclusively mined and processed by local, artisanal small-scale gold miners. With the increasing price of gold and the lack of alternative income generating activities over the past 20 years now more than 400 families in this region depend on artisanal gold mining as their only source of income. In this paper, I explore historical and current practices; and opportunities and barriers to achieving sustainability objectives regarding this mining activity within the context of the Sustainable Development Goals. Potential policy, technical, and community development efforts that protect the environment and public health while maintaining or improving income generation for this impoverished community are explored. These include the introduction of mercury-free processing techniques that also increase yield, the formation of cooperatives, vertical integration and product development, the development of gold related tourism, and sustainability certification programs.